Treatment of class III With miniplates and

mini-screwsprof. Maher fouda

Prepared by:- Bilal A.M.Faculty of dentistry-

Mansoura university - Egypt

INTRODUCTIONThe bone anchors are used to increase orthodontic anchorage in the anterior or posterior region of the upper and/or lower jaw. A 2 or 3 holes titanium mini plate is fixed by monocortical mini screws. The SAS is comprised of bone plates and fixation screws. The plates and screws are made of commercially pure titanium that is biocompatible and suitable for osseointegration. The anchor plate consists of the three components, the head, the arm, and the body.

The head component is exposed intraorally and positioned outside of the dentition so that it does not interfere with tooth movement. The head component has three continuous hooks for attachment of orthodontic forces. There are two different types of head components based on the direction of the hooks.

. The arm component is transmucosal and is available in three different lengths—short (10.5 mm), medium (13.5 mm), and long (16.5 mm) to accommodate individual morphological differences

ORTHODONTIC INDICATIONS1 Distal movement of the anterior segment in premolar extraction cases.2. Distal movement of the posterior and anterior segment in non-extraction cases.3. Mesial movement of posterior teeth.4. Intrusion of a single tooth or a group of teeth.5. Uprighting of mesialised lower second and third molars.6. Loss of dental anchorage because of periodontal diseases.7. Orthopaedic intermaxillary tractions.

CONTRA-INDICATIONSUnhealthy soft and hard tissues in implant region, poor dental hygiene.

Types of incisions used in mini-plates fixation

- Horizontal incision.

- Vertical incision.

- at the zygomatic buttress of the maxilla.

- nasal process of the maxilla

Anatomical sites for mini-plates placement

molar region of the mandible

canine region of the mandible

The zygomatic buttress and the canine region of the mandible are the anatomical sites recommended for the majority of the orthodontic applications.

SURGICAL METHOD FOR IMPLANT PLACEMENTIncision is the most important part of the surgical procedure. The correct location of the incision is decided by digital palpation. By using the index finger, the zygomatic buttress is palpated, and the incision is made along the buttress in a vertical or horizontal direction. In vertical direction, the lower border of the incision is at the intersection of the attached and the mobile gingiva, and the total length is no longer than 1 cm.

STEP-BY-STEP PROCEDUREIn the maxilla an L-shaped incision is made with anterior convexity. The vertical part of the incision (1) is made ± 1 cm mesial from and parallel to the infra-zygomatic crest and up to 2 mm below the muco-gingival boarder. The incision is extended distally (2) with a horizontal incision 2 mm below and parallel to the muco-gingival boarder.

The mini plate is slightly bended to obtain good contact to the cortical bone. The bending should be limited to the region between the holes in the mini plate. The connection between the mini plate and the neck should be slightly bended in the opposite direction to ensure good contact between the lower part of the neck and the alveolar bone.

The first screw is not completely fixed in order to allow some rotation of the mini plate. The lower hole is drilled and the mini screw is inserted, followed by the upper one and all are fixed for a strong stable retention.

After rinsing with saline solution, closure is obtained with elf resorbing sutures. The mucoperioteal flap is positioned by the first suture just anterior from the neck of the bone anchor. Additional sutures are placed until good closure is obtained. The fixation unit should be oriented parallel to the alveolar bone.

In the mandible a horizontal full thickness incision is made into the gingival sulcus along the marginal bone starting in front of the second premolar extending mesially and including the distal papilla of the canine. Just before the lowest point of the gingival margin in front of the canine the incision is continued vertically and slightly forward.

The bone anchor is positioned parallel to and between the roots of the canine and the first premolar. The neck should penetrate the soft tissues exactly at the level of the vertical incision and 2 mm above the muco-gingival boarder throughout attached gingiva. The first hole is drilled in the inter-radicular space between the canine and first premolar at the level of the roots apices.The first screw is inserted but not completely fixed to allow some rotation of the mini plate. The second screw is inserted in the mandibular body and both are fixed for a strong stable retention.

After rinsing with saline solution, closure is obtained in one or two planes with self resorbing sutures. Sutures are placed through both papilla and along the vertical incision.

RECOMMENDATIONS FOR THE ORTHODONTIST

• To reduce the risk for infections the placement of the bone anchor should never be combined with extractions of teeth.• Removal of the remaining stitches and oral hygiene instruction with toothbrush 10 days after surgery.• Continuous orthodontic lading is recommended 2 weeks after surgery. Therefore both arches should be orthodonticaly leveled before the placement of the bone anchor. The first month light forces are used.

• The orientation of the fixation unit can be slightly changed by finger pressure. Local anaesthesia is not needed.• The bone anchor should be removed when there is no more need for skeletal anchorage.

COMPLICATIONS- Development of InflammationInflammation may develop in any phase of treatment. In such a case, if the implant is not mobile, force application must be stopped and antibiotic treatment started, supported with bactericidal mouthwash. The healing period is about 15 days. Force application can be restarted when healing is complete, provided the implant is not mobile, which is unlikely.

- Soft Tissue Impingement on Palate If the palatal bars are not constructed far enough from the palate, they may impinge on the palatal mucosa during later stages of the dentoalveolar impaction. Bactericidal mouthwash may be used if the impaction is completed and the appliance is to be removed. If considerable impaction remains to be performed, the appliance should be replaced.

PATIENT INSTRUCTIONS• Ice application immediately after surgery to reduce swelling of the soft tissues.• Antiseptic mouth rinsing and gently brushing the region of the bone anchor in the first week after surgery.• Appointment with the orthodontist 10 days after surgery to remove the remaining sutures and for hygiene instruction.• Appointment 2 weeks after surgery to start orthodontic loading.• The patient should not touch the bone anchor with his tongue. These intermittent forces may be responsible for the loosening of the bone anchor some weeks after surgery.

Case reportFacemask therapy with miniplate implant

anchoragein a patient with maxillary hypoplasia

An 11-year old Chinese boy in late mixed dentition, Extraoral examination revealed that the maxilla wasretrognathic and the mandible was slightly prognathic.Intraoral examination revealed an anterior and posteriorcrossbite with a reverse overjet of 4 mm.

The molars were in class III relationship on both sides.There was no crowding in both maxillary and mandibular arches. Temporomandibular joint function was normal.Cephalometric analysis indicated a moderate skeletalclass III malocclusion due to both maxillary retrusion and mandibular protrusion. The mandibular plane was tilted 30° to S-N plane.

Treatment planThe patient and parents were concerned about dentofacial appearance. Treatment option was to use a facemask combined with fixed appliance to correct the anterior and posterior crossbite and improve facial esthetics.The patient and parents were informed that the treatment plan did not eliminate the possibility of orthognathic surgery later. Theunfavorable growth of the jaws during or after treatment might necessitate a surgical treatment plan. The use of miniplate implant as anchorage for maxillary protraction was suggested and the patient and parents agreed.

Treatment progressMiniplate implant placementTitanium miniplates were implanted by an experiencedoral surgeon. After mouth rinsing for 3 minutes with0.2% chlorhexidine gluconate, under local anesthesia, amucoperiosteal incision was made at the labial vestibulebetween the upper lateral incisors and canines on bothsides.

Miniplates were placed on the lateral nasal wall of maxilla.

The mucoperiosteal flap was then elevated, and the surface of the cortical bone at the apical region of lateral incisors and canines was exposed. An appropriate length of I-shaped miniplate (plate thickness 1 mm, 3 holes) was selected and fixed in position with self-tapping screws (diameter 2 mm, length 7 mm), with the head exposed to the oral cavity from the incised wound.

Care was taken to adjust the angle between the head and the body of the plates so that the head portion would not apply pressure on the attached gingiva. The incisions were finally closed and sutured with absorbable thread around the miniplate. This patient showed mild facial swelling for a week after the operation. It was necessary to take antibiotics and brush carefully

Maxillary protraction appliance designA month was allowed for healing before application offorce to the miniplates. After the month, the clinicalevaluation for the patient included an assessment of plate mobility and infection. If nothing was abnormal,maxillary protraction was started. First, thread a segment of brass wire through the hole in the head of miniplate. Second, a ganoid composite resin ball (diameter 2−3 mm) was made at top of brass wire. The ball was used for Protraction hook.

A protraction force of 450 g per side at first, 500−600 gper side after one month with an anteroinferior forcevector 30° to the occlusal plane, was applied from thecomposite ball in anchor miniplates to the facemask byusing elastic modules. The patient was instructed to wear facemask at least 10 hours a day and prolong the wearing time as much as possible.

Traction was continued for 6 months until enough forward movement of the maxilla had been achieved to improve the midface esthetics. After maxillary protraction, the miniplate implant was removedunder local anesthesia, then fixed appliance was bonded.

Treatment resultThe application of protraction force from a facemask to aminiplate resulted in a significant improvement in facial esthetics and the maxillo-mandibular jaw relation.SNA was changed from 79.89° to 82.53°, SNBangle from 84.16° to 81.67°, ANB angle from −4.27° to0.86°, Wits from −10.18 mm to −2.66 mm, A-NP distanceincreased by 5.48 mm, mandibular plane angle increased by 2°, while the change of U1/SN was not significant.

Maxillary protraction with miniplates providingskeletal anchorage in a growing Class III patient

An 8-year-old girl with a chief concern of “my bite is not right.”Clinically, she had a concave facial profile, and acute nasolabial angle, and a protrusive mandible.

Intraorally, she had an anterior crossbite and a low anterior tongue posture. The maxillary right firstdeciduous molar and left second deciduous molar hadexfoliated prematurely, and midarch crowding wasnoted on the dental casts and panoramic radiograph.The cephalometric radiograph and tracing showeda skeletal Class III malocclusion with maxillary deficiency, mandibular prognathism (ANB, –2.2), anda normal mandibular plane angle (FMA, 23).

The maxillary incisors were proclined (U1 to FH, 109), and the mandibular incisors were retroclined (IMPA, 86), compensating for the skeletal malocclusion. There was no family history of mandibular prognathism.

TREATMENT PROGRESSPhase 1 treatment was started at age 8 years 4months with a maxillary removable appliance to regainspace lost from the early loss of the deciduous molars. After 6 months of observation, a surgical miniplate was placed. Local infiltration anesthesia was administered to the maxillary left and right buccal vestibular areas after surgical disinfection.

A vestibular incision around the canine area was performed. After an atraumatic subperiosteal dissection to the infrazygomatic crest, a curvilinear miniplate was adapted, bent to the zygomatic buttress’s bony surface, and fixated with 3 self-tapping miniscrews per side.

At least 3 to 4 screws should be placed to resist the maxillary protraction force of about 300 to 400 cN per side. Screw placement should be in a posteriorsuperior direction to prevent damage to the premolar tooth follicles. The end of the miniplate entered the oral cavity between the canine and first premolar area in the keratinized attached gingiva to prevent gingival irritation. The oral portion of the miniplate was modified into a hook for elastic traction.

Maxillary protraction was started 2 weeks after placement of the miniplates, with a force of 300cN per side applied 12 to 14 hours per day. Within 10 monthsof treatment, a three quarters premolar width Class IImolar relationship was established. Thereafter, thepatient’s wearing of protraction headgear was limitedto nighttime only as a retainer for 10 months. The plateswere removed after the facemask treatment.

A mucoperiosteal incision and a subperiosteal dissection were performed to expose the miniplate. The monocortical screws were removed first, and the miniplate was then detached because often new bone is deposited next to the plate. The surgical site was then closed and sutured.Progress records taken at age 10 years 7 months showed favorable growth between the maxilla and the mandible, and the malocclusion could be camouflaged by orthodontic treatment.

The patient was treated with fixed appliances for 18 months to establish a good molar relationship and correct the midline discrepancy. A maxillary circumferential retainer and a mandibular lingual fixed retainer were placed after appliance removal. The patient was instructed to wear the retainer at night for 10 to 12 hours.

TREATMENT RESULTS

14 months after protraction headgear treatment. The malocclusion was overcorrected to a Class II molar relationship to compensate for future excessive mandibular growth.

Superimposition of pretreatment and posttreatmentcephalometric tracings showed 8.1 mm of forwardmovement of A-point (A-point to NtFH) and 3.3 ofcounterclockwise tipping of the palatal plane .The ANB angle changed from –2.2 to 1 6.7.

The SNO, or angle between the anterior cranial base and orbitale, changed from 63 to 70. Labial tipping of themaxillary incisors and lingual tipping of the mandibularincisors, which are typically observed after tooth-borneprotraction, were not seen with the miniplates.

after phase 2 fixed appliance treatment at age 12 years 6 months. The ANB angle was reduced from 6.7 to 3.9,indicating normalization of the jaw relationship afterovercorrection in the phase 1 treatment. Class I canineand molar relationships were obtained, and overjet andoverbite were returned to normal after phase 2treatment.

Intraoral photographs near the end of phase 2 fixed appliance treatment.

- patient at age 14 years 9 months, 27 months after the removal of the orthodontic appliances. During the retention period, the maxilla and the mandible showed relatively harmonious growth, maintaining an ANB difference of 3. The angle of convexity was reduced from 7.4 to 5.4.

Superimposition of the posttreatment and postretentioncephalometric tracings showed continuous dentalcompensation to the skeletal discrepancy was observedwith proclination of the maxillary incisors and slight retroclination of the mandibular incisors.

Orthopedic Traction of the Maxilla WithMiniplates: A New Perspective forTreatment of Midface Deficiency

J Oral Maxillofac Surg 67:2123-2129, 2009

Summary of Cases and DiagnosisThree girls (aged 10 to 11 years) presenting with asevere skeletal Class III relationship with a maxillarydeficiency and concave soft tissue profile were treated according to the same treatment plan. Two of them had an anterior crossbite without anterior shift of the mandible (cases 2 and 3). One had an edge-to-edge incisor occlusion in centric relation, with a forward posture into maximum intercuspation (case 1).

Pretreatment cephalometric evaluation of the 3 cases showed a skeletal Class III relationship with hypoplasia of the maxilla combined with a normal or increased mandibular size and normal or slightly decreased vertical dimensions. The patients’ upper incisors were proclined or retroclined, and the lower incisors were normal or proclined.

Treatment PlanThe 3 patients were treated exclusively by intermaxillarytraction between miniplates placed in themaxilla and in the mandible, in combination with abite plane to jump the crossbite.

Treatment ProgressFour orthodontic miniplates were inserted into the infrazygomatic crests and between the canine and lateral incisor or between the canine and first premolar in the mandible, on both the right and left sides. Surgery was performed with patients under general anesthesia (cases 1 and 2) or local anesthesia (case 3). The miniplates were fixed to the bone with 2 or 3 titanium screws (2.3 mm in diameter and 5 mm in length) after predrilling with a 1.6-mm-diameter bur, as previously described.

Three weeks after surgery, maxillomandibular elastics were attached between the upper and lower miniplates on each side, applying a force of 100 g per side. The patients were asked to replace the elastics once a day and to wear them 24 hours per day. After 1 month (case 1) or 2 months (cases 2 and 3), a removable bite plane was placed to eliminate the occlusal interference in the incisor region. At this time, the elastic force was increased to 200 g per side.

After 7 months (cases 1 and 2) or 12 months (case 3) of orthopedic traction, the bite plane was removed. The traction was maintained full time for a total period of 12 months (cases 1 and 2) or 16 months (case 3). No local infections were observed around any of the miniplates. They remained stable throughout treatment. During the follow-up period after the active treatment, the patients wore the elastics at night for retention.

ResultsThe anterior crossbite was corrected in each patient. Their soft tissue profiles considerably improved, with anterior displacement of the whole midface (infraorbital ridge, nose, and upper lip), reducing the paranasal concavity. Almost no anterior displacement of the lower lip and chin was observed at the end of the traction, leading to an improvement of the relationship between the upper and lower lip. The tip of the nose moved slightly upward.

Lateral cephalograms were taken at the beginningof treatment, at the end of orthopedic treatment, andat follow-up 11 to 38 months later.Cephalometric evaluation between the beginningof treatment and end of treatment showed a markedincrease of ANB, Wits, and facial convexity (G=-Sn-Pg=) values in all 3 cases . No rotation of themandible was observed in cases 1 and 3, whereas aslight clockwise rotation was seen in case 2; therewas a slight counterclockwise rotation of the maxillain all patients. No major changes occurred in theupper incisor inclination, whereas the lower incisorswere proclined. During the follow-up period (fromend of treatment to 11 to 38 months later), the ClassIII correction was maintained.

Treatment ofMaxillary Deficiency by Miniplates:

A Case Report

The patient was an 11-year-old boy who was referredfor treatment of maxillary deficiency. He had no medicalproblems, and there were no signs of temporomandibular joint dysfunction. The patient had a skeletal Class III malocclusion and maxillary deficiency. His parents had no Class III characteristics.

The facial photographs showed a Class III appearancewith a concave profile because of maxillary deficiency. The pretreatment intraoral photographs and dental casts showed Class III relationship of the central incisors and anterior crossbite. The patient had a Class III molar relationship on the right and Class I on the left side. Cephalometric analysis confirmed the Class III skeletalpattern. Treatment ObjectivesThe treatment objectives for this patient were to(1) correct the deficient maxillary arch, ideally by forwardpositioning of the maxilla;(2) obtain an ideal overjet and overbite;(3) correct the anterior crossbites.

Treatment AlternativesExtraoral appliances, such as protraction facemask, ClassIII functional appliance, any modified maxillary protraction devices, and orthognathic surgery, were considered as alternative treatments for the correction of this Class III malocclusion. However, the patient refused the use of extraoral appliances and major surgery. Therefore, in this case, it was decided to use miniplates to protract the maxilla by application of Class III elastics.

Treatment ProgressPlates for Orthodontic Anchorage were placed under local anaesthesia in the canine areas of the mandible by a maxillofacial surgeon. The ideal position for miniplates insertion was evaluated by using a panoramic radiograph in order to avoid damage to the roots of the adjacent teeth and mental foramen.

A tightly fitting and well-retained upper removable appliance was fabricated with two Adams clasps on the upper first permanent molars. Each of the Adams clasps had a loop which was used for retaining the elastics. A labial bow was also used on the anterior teeth for retention. A maxillary posterior bite plate was used to disclude the upper and lower jaws.

Orthodontic latex elastics (3/16 heavy size—UnitekElastics) were connected from the hooks of the miniplates to the Adams clasps of the removable appliance to generate approximately 500 g of anterior retraction. The patient was instructed to wear the appliance full-time except for eating, contact sports, and tooth brushing; he was also told to change the elastics every day. In order to retain these elastics, the Adams clasps on the molars were bent to form loops.

Treatment ResultsAfter 10 months of active treatment a positive overjet and Class I buccal segments were achieved and the anterior crossbite was corrected. The posttreatment cephalometric radiograph tracing showed a favourable increase of 5.1◦ and 4.4◦ in the SNA and ANB angles, respectively.

The pre- and posttreatment cephalometric superimposition on the anterior cranial base is shown in this Figure.

Skeletal Anchorage for Orthopedic

Correctionof Growing Class III

Patients

Bong-Kuen Cha and Peter W. Nga(2010)

Investigators have shown that maxillary protraction with palatal expansion therapy is an effective method for treatment of Class III patients. Although intervention in the primary or early mixed dentition may provide a better orthopedic response, treatment started in the late mixed or early permanent dentition can elicit reasonable orthopedic response when the circummaxillary sutures are still patent.

One of the limitations in maxillary protraction with a conventional tooth-borne type appliance is the loss of dental anchorage, especially in the dynamic period of the mixed or late permanent dentition.

Many investigators have attempted to design an absolute anchorage system for maxillary protraction. A priori ankylosed teeth, intentionally ankylosed maxillary deciduous canines, or osseointegrated titanium implants can be used as an absolute anchorage for protraction treatment.

However, the use of ankylosed teeth limits the orthopedic treatment to only the early mixed dentition period.Skeletal anchorage by the use of miniscrews or miniplates are gaining popularity as a source of absolute anchorage in contemporary orthodontics.Kuen Cha.B and Nagan.P quantified and compared the effects of maxillary protraction using surgical miniplates as anchorage to maxillary protraction in conjunction with an expansion appliance (rapid maxillary expansion [RME]).

Methods

Two treatment modalities for the correction of Class III malocclusions in growing patients were compared by treating 2 groups of patients. One group of 25 patients (16 girls and 9 boys) was treated with a facemask combined with a bonded RME and a second group of 25 patients (15 girls and 10 boys) treated with a facemask employing a surgical miniplate as anchorage.

Schematic illustration shows a curvilineartype miniplate fixed with 3 self-tapping miniscrews on the zygomatic buttress area. The end of the miniplate was exposed between the canine and first premolar area, located over the keratinized attached gingiva to prevent gingival irritation. Protraction force is approximately 300-400 gm per side and the line of force is 30° to the occlusal plane.

The placement of miniplates was carried out under local anesthesia.The anchor plates were placed at the zygomatic buttress area to avoid damage to the underlying developing tooth buds of the permanent teethProtraction force is most often applied after

3 or 4 weeks of healing.

The facemask was inserted after maxillary expansion or placement of the miniplate the total force applied was 400 g/side.

Patients in both treatment groups were instructed to wear the appliance for at least 14-16 hours a day.Posttreatment cephalometric radiographs were taken when a normal dental relationship was obtained with an overjet of 2-3 mm.

The average treatment time in miniplate group was 9.2 2.4 months and the RME group 8.5 2.4 months.

Pretreatment records of 11-year, 4-month-old male patient (THC) with Skeletal Class III malocclusion and anterior crossbite, crowding. The concave profile is shown in the lateral photograph.

Patient (T.H.C.) treated with a face mask with the skeletal anchorage system for 11 months.

Facial and intraoral photographs of patient T.H.C. after 10.5 months of protraction treatment. After protraction with miniplate, Class III malocclusionhas been corrected.

Pretreatment records of a 10-year, 8-month-old female patient (J.E.C.) with skeletal Class III malocclusion and anterior crossbite. Loss of space for upper right second premolar attributable to mesial movement of right first molar. Showing concave profile in lateral photograph.

Facial and intraoral photographs of J.E.C. during the maxillary protraction with miniplates. Pendulum appliance was used simultaneously to gain space for the right second premolar.

Results

No significant differences were found between the 2 groups in dentofacial morphology except for the lower incisal inclination (IMPA was 80.68° for the miniplate group and 85.69° for the RME group, P 0.05).Skeletal ChangesThe anterior and posterior cranial base lengths were found to increase significantly in both treatment groups.However, no significant differences were found between the 2 groups.

The measurement SNA was found to increase significantly by 3.29° in the miniplate group and 2.22° in the RME group. The changes were significantly greater in the miniplate group.

Similarly, the measurement A to perpendicular to FH was found to increase by 3.42 mm in the miniplate group and 2.13 mm in the RME group . The changes were also significantly greater in the miniplate group .

With treatment, the mandible was found to rotate downward and backward in both treatment groups.The mandibular plane angle (FMA) was found to increase significantly in both the miniplate group (1.01°) and the RME group (1.74°).A greater increase in the forward position of the maxilla was found in the miniplate group compared with the RME group. Such a difference can be explained by direct transmission of the orthopedic force to the maxillary sutures in the miniplate group.

The placement of miniplates in the zygomatic buttress area is closer to the center of resistance of the maxilla which is usually located half way between the infraorbital rim and the mesial buccal cusp of the maxillary molars.In contrast, orthopedic force in the RME group

is directed along the occlusal plane rather than at the center of resistance of the maxilla. Consequently, bone remodeling occurs not only at the circummaxillary sutures but also within the periodontal tissues.

Palatal expansion has been shown to disarticulate the maxilla and initiate cellular response in the suture, allowing a more positive reaction to protraction forces.

The maxillary first molars were found to move backward 0.46 mm compared with a forward movement of 3.26 mm in the RME group.

Vertically, significant extrusion of the maxillary first molars were found in both treatment groups.

The maxillary incisors were found to move forward by 0.11 mm in the miniplate group compared with 1.83 mm in the RME group.

Dentoalveolar changes

Three-dimensional analysis of maxillary

protraction with intermaxillary elastics to

miniplates

Heymann et al (2010)said that the Protraction face-mask therapy or reverse-pull headgear (RPHG) is perhaps the most common approach for early treatment of young Class III patients with maxillary deficiency This approach is limited in that the forces are

applied to the teeth, resulting in uncertain skeletal and often unwanted dentoalveolar effects.

For satisfactory clinical improvement, excellent compliance with an extraoral appliance is required and treatment regimns recommended wearing the appliance for 12 to 16 hours per day for 9 to 12 months.

most investigations have described some limited orthopedic effect on the maxilla (2–3 mm of advancement on average), clockwise rotation of the mandible, and dentoalveolar changes consistent with treatment of Class III malocclusion (proclination of maxillary incisors and retroclination of mandibular incisors).

Long-term follow-ups of maxillary protraction indicate a 25% to 33% chance of relapse to negative overjet after all mandibular growth is complete.

Since dentoalveolar changes tend to be the most prone to relapse, it seems advantageous to minimize the dentoalveolar effects while maximizing the orthopedic correction.Heymann et al used. An alternative treatment of early Class III with intermaxillary elastics from a temporary anchorage device that might permit equivalent favorable skeletal changes without the unwanted dentoalveolar effects.

MATERIAL AND METHODS

Criteria for participation in the study were 9–14 years of age at the start of treatment, skeletal Class III due primarily to maxillary deficiency (determined by clinical examination including profile evaluation), Class III dental occlusion determined by the permanent first molars or overjet ≤0 mm, and sufficient dental development, to avoid injury to unerupted mandibular permanent canines during surgical placement of the miniplates.

Six consecutive patients (3 boys, 3 girls; ages, 10–13 years 3 months) with Class III occlusion and maxillary deficiency were treated by using intermaxillary elastics to titanium miniplatesAll 6 patients were at prepubertal cervical vertebral maturation stages.

In the surgical procedure, 4 miniplates were placed in each patient—1 in each infrazygomatic buttress of the maxilla and 1 in the anterior mandible between and inferior to the left and right permanent lateral incisor and canine.

The modified titanium miniplates incorporated an intraoral attachment with a locking fixation screw to allow customizable traction hooks In all sites, the miniplates were placed with the attachment arm exiting through attached tissue at or near the mucogingival junction.

The miniplates were loaded 3 weeks after surgery. One elastic was placed on each side to give vectors of force downward and forward for the maxilla and backward and upward (counterclockwise) for the mandible. The patients were instructed to wear elastics 24 hours per day. The elastics were chosen to provide an initial force of approximately 150 g to each side, increased to 200 g after 1 month of traction and to 250 g after 2 months. The forces were measured with the patient in maximum intercuspation by using a Correx force gauge

The miniplates were loaded 3 weeks after surgery. One elastic was placed on each side to give vectors of force downward and forward for the maxilla and backward and upward (counterclockwise) for the mandible. The patients were instructed to wear elastics 24 hours per day. The elastics were chosen to provide an initial force of approximately 150 g to each side, increased to 200 g after 1 month of traction and to 250 g after 2 months. The forces were measured with the patient in maximum intercuspation by using a Correx force gauge

All patients in this study showed a negative change on the anterior surfaces of the condyles and a positive change on the posterior surfaces, suggesting that there was at least some posterior repositioning of the mandible.All 6 patients had a positive change at the

surface region that encompassed the upper lip as the underlying hard tissues of the maxilla changed.In 5 of 6 patients, the entire nasal complex appeared to rotate anteriorly and superiorly, suggesting that the forces from the TADs were dispersed widely through the nasomaxillary complex.

It has been well documented that facemask treatment results in an increase in maxillary incisor angulation and a decrease in mandibular incisor angulation.Dentoalveolar effects observed in this study tended to be in the opposite directions, possibly as a result of alteration of soft-tissue equilibrium forces. The use of CBCT for this study allowed the treatment changes to be visualized and described in greater detail than with 2-dimensional (2D) imaging alone.

Skeletal Anchorage for Orthopedic

Correctionof Growing Class III

Patients

Bong-Kuen Cha and Peter W. Nga(2010)

Investigators have shown that maxillary protraction with palatal expansion therapy is an effective method for treatment of Class III patients. Although intervention in the primary or early mixed dentition may provide a better orthopedic response, treatment started in the late mixed or early permanent dentition can elicit reasonable orthopedic response when the circummaxillary sutures are still patent.

One of the limitations in maxillary protraction with a conventional tooth-borne type appliance is the loss of dental anchorage, especially in the dynamic period of the mixed or late permanent dentition.

Many investigators have attempted to design an absolute anchorage system for maxillary protraction. A priori ankylosed teeth, intentionally ankylosed maxillary deciduous canines, or osseointegrated titanium implants can be used as an absolute anchorage for protraction treatment.

However, the use of ankylosed teeth limits the orthopedic treatment to only the early mixed dentition period.Skeletal anchorage by the use of miniscrews or miniplates are gaining popularity as a source of absolute anchorage in contemporary orthodontics.Kuen Cha.B and Nagan.P quantified and compared the effects of maxillary protraction using surgical miniplates as anchorage to maxillary protraction in conjunction with an expansion appliance (rapid maxillary expansion [RME]).

Methods

Two treatment modalities for the correction of Class III malocclusions in growing patients were compared by treating 2 groups of patients. One group of 25 patients (16 girls and 9 boys) was treated with a facemask combined with a bonded RME and a second group of 25 patients (15 girls and 10 boys) treated with a facemask employing a surgical miniplate as anchorage.

Schematic illustration shows a curvilineartype miniplate fixed with 3 self-tapping miniscrews on the zygomatic buttress area. The end of the miniplate was exposed between the canine and first premolar area, located over the keratinized attached gingiva to prevent gingival irritation. Protraction force is approximately 300-400 gm per side and the line of force is 30° to the occlusal plane.

The placement of miniplates was carried out under local anesthesia.The anchor plates were placed at the zygomatic buttress area to avoid damage to the underlying developing tooth buds of the permanent teethProtraction force is most often applied after

3 or 4 weeks of healing.

The facemask was inserted after maxillary expansion or placement of the miniplate the total force applied was 400 g/side.

Patients in both treatment groups were instructed to wear the appliance for at least 14-16 hours a day.Posttreatment cephalometric radiographs were taken when a normal dental relationship was obtained with an overjet of 2-3 mm.

The average treatment time in miniplate group was 9.2 2.4 months and the RME group 8.5 2.4 months.

Pretreatment records of 11-year, 4-month-old male patient (THC) with Skeletal Class III malocclusion and anterior crossbite, crowding. The concave profile is shown in the lateral photograph.

Patient (T.H.C.) treated with a face mask with the skeletal anchorage system for 11 months.

Facial and intraoral photographs of patient T.H.C. after 10.5 months of protraction treatment. After protraction with miniplate, Class III malocclusionhas been corrected.

Pretreatment records of a 10-year, 8-month-old female patient (J.E.C.) with skeletal Class III malocclusion and anterior crossbite. Loss of space for upper right second premolar attributable to mesial movement of right first molar. Showing concave profile in lateral photograph.

Facial and intraoral photographs of J.E.C. during the maxillary protraction with miniplates. Pendulum appliance was used simultaneously to gain space for the right second premolar.

Results

No significant differences were found between the 2 groups in dentofacial morphology except for the lower incisal inclination (IMPA was 80.68° for the miniplate group and 85.69° for the RME group, P 0.05).Skeletal ChangesThe anterior and posterior cranial base lengths were found to increase significantly in both treatment groups.However, no significant differences were found between the 2 groups.

The measurement SNA was found to increase significantly by 3.29° in the miniplate group and 2.22° in the RME group. The changes were significantly greater in the miniplate group.

Similarly, the measurement A to perpendicular to FH was found to increase by 3.42 mm in the miniplate group and 2.13 mm in the RME group . The changes were also significantly greater in the miniplate group .

With treatment, the mandible was found to rotate downward and backward in both treatment groups.The mandibular plane angle (FMA) was found to increase significantly in both the miniplate group (1.01°) and the RME group (1.74°).A greater increase in the forward position of the maxilla was found in the miniplate group compared with the RME group. Such a difference can be explained by direct transmission of the orthopedic force to the maxillary sutures in the miniplate group.

The placement of miniplates in the zygomatic buttress area is closer to the center of resistance of the maxilla which is usually located half way between the infraorbital rim and the mesial buccal cusp of the maxillary molars.In contrast, orthopedic force in the RME group

is directed along the occlusal plane rather than at the center of resistance of the maxilla. Consequently, bone remodeling occurs not only at the circummaxillary sutures but also within the periodontal tissues.

Palatal expansion has been shown to disarticulate the maxilla and initiate cellular response in the suture, allowing a more positive reaction to protraction forces.

The maxillary first molars were found to move backward 0.46 mm compared with a forward movement of 3.26 mm in the RME group.

Vertically, significant extrusion of the maxillary first molars were found in both treatment groups.

The maxillary incisors were found to move forward by 0.11 mm in the miniplate group compared with 1.83 mm in the RME group.

Dentoalveolar changes

Distraction Osteogenesis Treatment of Maxillary

Deficiency for Cleft Patient Using Internal Distraction

Device: A Case Report

Keinprasit et al (2010) treated a case of severe maxillary hypoplasia in a 21 years old male Thai patient with a complete unilateral cleft of primary and secondary palates by internal distraction osteogenesis for maxillary advancement.

Case history:

The patient was a 21 years old Thai male with a repaired right complete unilateral cleft lip and palate with severe Class III malocclusion and very severe midfacial hypoplasia.The cleft lip was repaired at the early infant period, and the cleft palate at four years of age. Secondary alveolar bone grafting was completed when he was 19. There was velopharyngeal insufficiency that produced hypernasal speech.

Extraoral examination showed a symmetrical dolicofacial type with a concave profile and flat paranasal areas due to underdeveloped maxilla. The mandibular plane was steep.

Intraorally, there was a pegged-shape lateral incisor in the lateral segment next to the cleft area.The occlusion was Class III with total

crossbite and 6 mms negative overjet.

There was an incomplete anterior bite with 0% vertical overlapping.The lower dental midline was deviated 1 mm to the left.

Both maxillary first premolars and left maxillary first molars were missing with residual spaces.There was 3 mms crowding in the anterior region.Mandibular first molars were missing with the second molars drifted into the spaces.

Cephalometric analysis showed a skeletal Class III relationship (ANB-6.5°) due to retrognathic maxilla (SNA 82.5°, A-Nperp -6 mms) and prognathic mandible (SNB 89°, Pog-Nperp +3 mms).Open vertical skeletal relationship (PP-MP 29.5°) was presented due to anterior inclination of palatal plane (SN-PP 1.5°) and opening rotation of mandibular plane (SN-MP 31°), causing decreased facial index (73%).

Treatment:

The treatment plan was orthodontic treatment combined with maxillary distraction osteogenesis to correct skeletal discrepancy and improve facial appearance.Predistraction orthodontic treatment to level and align the dentition and close all edentulous spaces was planned.The objective of maxillary distraction is to advance and anteriorinferiorly reposition of the maxilla, so that mandibular set back would not be necessary to reduce its prognathism.

After the distraction, treatment would be completed by finishing orthodontics.

The treatment was begun in early 2004 for arch leveling, aligning, space closures and inter-arch coordination. Predistraction orthodontic preparation was completed in 2007

The surgical approach for distraction was similar to a Le Fort I osteotomy.Circumvestibular incision and complete osteotomy were performed and the maxilla was then down-fractured.The distraction vector was oblique to the occlusal plane to move the maxilla anteriorly and inferiorly. The devices were activated to test their function and the mobility of the released bone segment and then returned to the starting positions.The surgical wound was closed with the two activation ports exited through the mucosa into the buccal vestibules.

The device activation was started after a 5 days latency period.

Both Synthes® screws were activated by oral surgeons at a rate of 0.25 mm twice a day for 2 weeks and then 0.5 mm once a day for another week until 8 mms maxillary advancement with 1 mm positive overjet were obtained.After 4 months of complete bone consolidation, the distractors were removed and postdistraction orthodontic treatment was started. Intermaxillary Class III elastics were applied to produce 3 mms incisor overjet for overcorrection and prevention of anterior crossbite relapse. Satisfactory occlusion was achieved. There was no longer any posterior crossbite.

Retention period photographs, at 20 months after orthodontic appliance removal

New treatment modality for maxillary hypoplasia in cleft

patients

Baek et al (2010) reported a case report of a patient was a 12 year 1 month old girl with CP only. She presented with concave facial profile, anterior crossbite (29 mm overjet), and anterior open bite (22 mm overbite). Cephalometric analysis showed skeletal Class III malocclusion with maxillary hypoplasia.

(ANB, -5.4; A to N perp, -3.4 mm), steep mandibular plane angle (FMA, 32.7u), and a skeletal age after the pubertal growth spurt according to the cervical vertebrae maturation index (CVMI, stage 4). Her condition was one of the contraindications for conventional facemask therapy.

Treatment ProgressFM/MP therapy was started 4 weeks after placementof the miniplates according to the protocol.During protraction, the fixed appliances were placedto align the dentition.

Treatment ResultsAfter 16 months of FM/MP therapy, there was significant forward movement of the point A (A to N perp, 5.6 mm). The ANB angle was changed from - 5.4° to 2.9°, and a Class II canine and molar relationship, normal overbite, and overjet were obtained. A slight counterclockwise rotation of the occlusal plane angle (-1.8) was interpreted to mean that there was almost no side effect such as extrusion of the upper molars.

Although the FMA was increased 4.3, the anterior open bite was corrected by downward and forward movement of the maxilla. Slight labial tipping of the upper incisors (U1 to SN, 2.0°) occurred after correction of anterior crossbite and open bite

Orthopedic Protraction with Skeletal Anchorage in a Patient with

Maxillary Hypoplasia and Hypodontia

Kircelli et al (2006) presented a case report of a 11-year-old girl was referred with a complaint of‘‘small and separated teeth’’ and ‘‘lower jaw projection.’’ Medical history of the patient was noncontributory other than her parents were cousins. Furthermore, her elder brother presented with similar complaints of maxillary hypoplasia and hypodontia. Clinical and radiological examination revealed severe hypodontia and microdontia. Twenty-one of her permanent teeth were missing, whereas number 11, 21, 36, 46 existed in the dental arch and germs of the number 15, 37, and 47 could be detected on the panoramic radiograph.

Furthermore, microdontia existed both in her primary and permanent dentition. The maxillary arch was deficient sagittally and transversally, so that there was an eight mm negative overjet and a bilateral buccal crossbite relationship with the lower jaw.

A depression of the midfacial structures included the maxillary and infraorbital regions with a relative prominence of the mandible, inadequate projection of the nasal tip and an old face appearance with an unesthetic smile constituted general features of the patient . She also had nasal respiratory problems causing mouth opening during sleep.

Three treatment options were considered for maxillaryadvancement. The first option was to delay treatment until growth has ceased and to correct the jaw relationship by orthognathic surgery. The second option was to apply rigid external distraction together with complete Le Fort I osteotomy. The third option was to try to take advantage of the sutural growth potential by applying extraoral force with a face mask via rigid skeletal anchors placed to the maxillary bone.

Treatment options

A titanium miniplate designed by Erverdi16 (MPI, Tasarımmed, Istanbul, Turkey) was used as a rigid skeletal anchor to attach the elastic orthopedic forces to the maxilla. Multipurpose miniplates were to be placed on both sides of the apertura piriformis and on the lateral nasal wall of maxilla. Rapid maxillary expansion was also planned to correct the transversal maxillary deficiency and to disturb the circummaxillary sutures.

Because the maxillary dentition was insufficient, it was decided to place intraosseous titanium screws (two 3 eight mm IMF screws, Leibinger, Germany) on the palatal bone, near the alveolar crests, to provide anchorage for the expansion appliance. After routine surgical preparations, patient received general anesthesia. Bilateral mucosal incisions were made on labial sulcus between lateral incisor and first cuspid region.

Then, mucosal flaps were carried inferiorly, the muscles and periosteum were incised and reflected superomedially, exposing the apertura piriformis and the lateral nasal wall of maxilla on both sides. Once an adequate space was achieved for miniplate placement, the nasal mucoperiosteum was elevated. Multipurpose miniplates were meticulously contoured to the bilateral lateral nasal wall, and straight extensions were bent to hook shape providing retention for face mask elastics and projected into the oral cavity through three mm mucoperiosteal incisions made inferiorly on the attached gingiva.).

Subsequently, for final stabilization of the bone plates three, 2.0 mm screws (five mm length) were placed with a 1.3 mm diameter drill under copious irrigation Simultaneously, four intraosseous bone screws were placed in the anterior and posterior palatal region, close to the alveolar crests, bilaterally .After soft tissue healing, orthopedic forces were applied.

IMF screws placed in anterior and posterior palatal region.

Impressions and stone casts were obtained with th IMF screws in place. The screws were blocked out with wax on the stone model, and an acrylic plate was prepared with an expansion screw in the midline. Appliance adaptation was checked intraorally and then connected to the IMF screw heads using cold curing methyl methacrylate–free acrylic resin (Ufi Gel hard, Voco GmbH, Cuxhaven, Germany). One of the parents was asked to activate the screw a quarter turn once a day.

Construction of the intraosseous screw– supported expansion appliance

Intraosseous screw–supported maxillary expansion appliance.

An elastic force of approximately 150 g was applied bilaterally to the miniplate extensions after the adaptation of face mask (Leone spa, Firenze, Italy). After being sure of the stability, the force was increased gradually to 350 g. The direction of the force was adjusted approximately 308 to the occlusal plane, and the patient was asked to wear the face mask full time except during meals.

Procedures for the face mask therapy

The application of the orthopedic forces via elastics directly to the anterior part of the maxillary bone by using miniplate anchorage resulted in a remarkable improvement in the middle face. Together with the maxillary bone advancement, significant enhancement in the soft tissue profile revealed improved facial esthetics. The maxilla was expanded from the median palatal suture, and seven mm of expansion was achieved across the buccal segments. Coordination of the dental arches both in the sagittal and transversal planes created improved physiological functions.

Post treatment extraoral frontal and lateral view showinga remarkable improvement in midface and soft tissue profile.

Post treatment intraoral photographs.

Early Class III Treatment with a Hybrid Hyrax-Mentoplate

Combination

JCO/JANUARY 2011

Clinical ProcedureAfter administration of topical anesthesia, two mini-implants with interchangeable abutments (2mm × 9mm, Benefit system) are inserted with a contra-angle screwdriver next to the midpalatal suture, near the second and third palatal rugae.

Benefit system. A. Mini-implant. B. Laboratory analog. C. Impression cap. D. Wire abutment with wire in place. E. Bracket abutment. F. Standard abutment. G. Slot abutment. H. Screwdriver for abutment fixation

An implant diameter of 2mm is recommended for better stability. A dental probe is used to measure soft-tissue thicknesses from anterior to posterior and to identify a region with thin mucosa, which will ensure primary stability and avoid long lever arms. Pre-drilling is not needed in young patients because of the low mineralization of the bone.

At the same appointment, bands are fitted to the upper first molars. After transfer caps are placed over the miniscrews, a silicone impression is taken.*** If the space between the mini-implants is narrow, the transfer caps can be cut to fit side-by-side. The angular relationship of the transfer caps is maintained by connecting them with a light-cured adhesive in the mouth. After the impression is taken, the laboratory analogs are placed over the transfer caps.

Two standard Benefit system abutments are then screwed over the laboratory analogs. A standard Hyrax‡ palatal split screw is connected by laser-welding it anteriorly to the two abutments and posteriorly to the molar bands. The appliance can still be fitted over the implants even if they are not absolutely parallel.

The Hybrid Hyrax is inserted one week later by pressing it gently over the mini-implants and alternately screwing the two abutments onto the mini-implants. To facilitate the installation, we recommend use of a light-cured cement for the molar bands. The expansion screw should be activated immediately after insertion of the Hybrid Hyrax; turning the screw 180° twice a day results in a daily expansion of .8mm.

The oral surgeon places the titanium Mentoplate in the mandible under local anesthesia. After preparation of a mucoperiosteal flap, the two extensions are shortened and adapted. The extensions should penetrate the soft tissue in the attached mucosa

After the Mentoplate is fixed with four screws, the flap is flipped back and sutured.They have treated seven young Class III patients (three males, four females; average age 10.6) with this Hybrid Hyrax-Mentoplate combination. All patients began wearing Class III elastics§ (3.5oz, 3/16 ") immediately after maxillary expansion. The following are representative cases.

Case 1A 9-year-old female presented with a severe skeletal (Wits: −8.3mm) and moderate dentoalveolar Class III malocclusion. A Hybrid Hyrax and Mentoplate were placed.

After one week of rapid maxillary expansion, Class III elastics were applied. The soft tissues appeared healthy throughout treatment.

After nine months of treatment, the patient’s occlusion and profile showed impressive improvement (Wits: −2.8mm).

A 12-year-old male presented with a severe skeletal Class III malocclusion (Wits: −5.9mm) and negative overjet

A Hybrid Hyrax was activated one week after insertion of the Mentoplate and Benefit mini-implants. Resin bite-opening blocks were bonded to the lower molars to facilitate correction of the anterior crossbite. No soft-tissue impingement by the Mentoplate was observed.

After six months, the patient demonstrated substantial occlusal and skeletal improvement (Wits: −2.7mm). The profile was also markedly improved 14 months later, at the end of orthodontic treatment.

Case 2. Reverse overbite corrected after six months of treatment. B. Profile after 20 months of orthodontic treatment.

DiscussionAmong the seven young patients, none of the 14 Benefit mini-implants placed in the anterior palate has failed, and no complications have been observed. We prefer the anterior palate for insertion of the Hybrid Hyrax because of its superior bone quality and relatively low rates of miniscrew failure.7 The attached mucosa offers better stability than other areas, and there is no risk of tooth damage. Usually the screws are removed without anesthesia.The Hybrid Hyrax can also be used for rapid palatal expansion in patients with inadequate anterior dental anchorage (missing deciduous teeth or premolars with underdeveloped roots). The heavy forces associated with other methods may cause root damage or curvature if the premolars have just erupted.

None of the seven Mentoplates has failed in our patients, although we observed mild irritation in cases where the plate extensions passed over the mobile mucosa. Based on these results, it appears that the Mentoplate could be useful not only in orthopedic treatment, but in orthodontic correction as well. Considering that mini-implant failure rates in the alveolar process are relatively high, the mental region appears to be a better site for mandibular skeletal anchorage it is the “anterior palate” of the lower jaw.

The Hybrid Hyrax-Mentoplate approach for early Class III treatment offers several advantages over other methods:• Forces are applied directly (by the Mentoplate) or transferred indirectly (Hybrid Hyrax) to skeletal structures.• The appliances are nearly invisible; no extraoral devices are required.• Rapid expansion opens the midpalatal sutures for better maxillary protraction.• Anchorage is stable and reliable.• Insertion is possible before complete eruption of the lower canines.

• The placement procedure is less invasive than when multiple miniplates are used.• The upper and lower arches remain fully accessible for orthodontic tooth movements.This combination of the Hybrid Hyrax and the Mentoplate seems to offer a promising approach for early treatment of patients with Class III malocclusion.

Treatment of class III With mini-screws :

Case reports

Nonsurgical correction of a Class III malocclusion in an adult by miniscrew-

assisted mandibular dentition distalization

American Journal of Orthodontics and Dentofacial Orthopedics June 2013 Vol 143 Issue 6

In this case report, they introduce a nonsurgical treatment of an adult with a Class III malocclusion withminiscrew-assisted mandibular teeth distalization.At the beginning of the therapy, the multiloop edgewise archwire technique resulted in an unsatisfyingsmile because of the excessive proclination of themaxillary incisors. Then they used a miniscrews in the mandible as anchorage for the distal en-masse movement of the mandibular dentition and obtained an excellent treatment outcome ultimately.

DIAGNOSIS AND ETIOLOGYThe patient was a 20-year-old Mongolian womanwho had a Class III facial type and slight crowding witha complete Class III relationship. Her chief complaintwas an anterior crossbite. Her medical history showedno contraindication for orthodontic therapy, and noone in her direct family had skeletal Class III features.

The photographs taken before treatment showedsymmetric facial structures. The patient had a concave facial profile, a protrusive lower lip, and an acutenasolabial angle.

Her maxillary anterior teeth were retrognathic, with inadequate display when smiling.The mandibular dental midline was deviated 2.0 mm tothe right, although the maxillary dental midline wascoincident with the facial midline. There were no signsor symptoms of temporomandibular joint dysfunction.

A cephalogram and a panoramic radiograph were taken before treatment. The cephalometric analysis and its tracing showed that the SNB angle 81.7 and ANB angle, 2.6. The panoramic radiograph showed no other abnormal signs, except that the 2 germs of the mandibular third molars were tipped mesially.

TREATMENT OBJECTIVESThe treatment objectives were to (1) obtain a harmonious facial profile by decreasing the protrusionof the mandible; (2) improve the occlusion, includingcorrection of the anterior crossbite, establishment ofideal overjet and overbite, and achievement of Class Imolar relationships; and (3) place the dental midlinesin the middle of the patient's face.

TREATMENT ALTERNATIVESThe first alternative was combined surgical andorthodontic treatment. The anterior crossbite would becorrected with a mandibular setback, and the concaveprofile would be improved as well. However, they decided that her skeletal problem was not sufficiently excessive to require orthognathic surgery.The second alternative was orthodontic treatmentwith extraction of 4 premolars. Through the retractionof the mandibular anterior teeth and the mesialmovement of the maxillary molars, the anterior crossbiteand Class III molar relationships would be corrected, and the concave facial profile would be camouflaged.

Nevertheless, her mandibular incisors were not suitablefor much distal movement because of the thin trabecularbone in the mandibular anterior area that could damagethe periodontal tissues by gingival recession, fenestration or dehiscence.

The third alternative was to extract the mandibularthird molars and use the multiloop edgewise archwiretechnique to obtain distal en-masse movement of themandibular arch with short Class III elastics. Thereby,the anterior crossbite would be corrected, the molarrelationships would be changed into Class I, and herconcave facial profile would be camouflaged as well.

After they discussed the 3 alternatives with the patient,she chose the third option and promised to cooperate in extracting the third molars and wearing the Class III elastics.

TREATMENT PROGRESSOrthodontic treatment began on November, 2007.The mandibular third molars were extracted beforebonding. Preadjusted 0.022-in brackets were bonded to all teeth. Alignment and leveling with sequential nickel-titanium archwires were achieved in 12 months, ending with 0.018 X 0.025-in stainless steel wires. After that, 0.018 X 0.025-in stainless steel multiloop edgewise archwires with progressive tip-back bends were placed in both arches.

The patient was instructed to wear the short Class IIIelastics (3/16 in, 6 oz; 3M Unitek, Monrovia, Calif) for24 hours per day.

The anterior crossbite was corrected substantially4 months later. However, the maxillary incisors wereproclined remarkably. Class I molar relationships werenot completely established, although the overallocclusion was improved significantly. Thus, in the 17th month, they took a set of photos and a cephalogram, and made a cephalometric analysis to re-estimate her treatment.

The superimposition of the cephalograms showed that the correction of the anterior crossbite was mostly because of the proclined maxillary incisors without obvious distal movement of the mandibular incisors. Also, the excessively proclined maxillary anterior teeth made her facial profile worse, especially when smiling.

To reinforce the distal en-masse movement of themandibular dentition, they modified the treatment plan.They replaced the orthodontic appliance with 0.022-inDamon III self-ligating brackets and used miniscrews instead of the multiloop edgewise archwire technique. When rebonding, the maxillary incisor brackets were rotated 180, assisting in labial root torque at the rectangular wire stage.

The miniscrews were implanted vertically in the external oblique ridge areas of the bilateral mandibular ramus between the mandibular first and second molars, where the greatest thickness of buccolingual bone was found.

After 3 months of re-leveling, they started to draw themandibular dentition distally using nickel-titaniumcoil springs with 300-g forces on each side. The springwas connected from the miniscrew to the hookbetween the mandibular canine and the first premolar.At the same time, 0.019 X 0.025 beta-titanium alloywire was used to control the root position of themaxillary incisors.

Six months later, the anterior overbite and overjet were improved remarkably, and the labial inclination of maxillary teeth was also much better.

The total treatment duration was 32 months. The multiloop edgewise archwire technique was used for 4 months, and it took 12 months for the distal en-masse movement of the mandibular dentition with miniscrews. The miniscrews were stable all the time and removed under topical anesthesia.

TREATMENT RESULTSA harmonious facial balance, a charming smile, anda well-aligned dentition were obtained. The anterior crossbite was corrected, and Class I molar relationships were achieved. The post-treatment cephalometric analysis and the superimposition show that the ANB angle increased from - 2.6 to -1.5, and the SNB angle decreased from 81.7 to 79.1. According to the superimposition, the mandibular anterior teeth were retracted about 4 mm without negative lingual inclinations.

The movement of the mandibular first molar could be considered almost bodily translation because its crown was moved 4.0 mm distally, and its roots were moved 3.0 mm distally. The maxillary incisors were moved labially under control with good inclination (U1-SN, 77.7). The SN-GoGn angle increased from 36.1 to 38.9, and S-Go/N-Me decreased from 61.3% to 59.4%, indicating that the mandible had rotated clockwise slightly. The patient was satisfied with the treatment results, and the outcome was stable after 1 year of retention.

Because the direction of the retraction force applied to the miniscrews is above the center of mandibular arch resistance, the mandibular arch can be rotated counterclockwise when distalized, leading to a flattened occlual plane. On the other hand, molar distalization is beneficial for decreasing a negative overbite. With the combination of these 2 factors, the anterior crossbite can be corrected, and ideal overbite and overjet can be established. The dotted line represents the retraction force; the red point represents the center of mandibular arch resistance.

Distalization of the mandibular dentition with

mini-implants to correct a Class III malocclusion

with a midline deviation(Am J Orthod Dentofacial Orthop 2010;137:135-46)

When distalizing the mandibular dentition with a mandibular C-implant, the most important consideration is its position. The placement site should be as close as possible to the mesial surface of the mandibular first molar because this will help achieve optimal distalizationof the mandibular dentition. The initial tooth movement in distalization is posterior movement of the second molar by using a sliding jig that is connected to the main archwire, followed by moving the other teeth posteriorly.

While the second molar is distalizing, the first molar also moves distally as a result of drifting. When molar distalization is complete, the premolars will also begin to move with the sliding jig. While the premolars are distalizing, spaces might develop between the anterior teeth. To retract the anterior teeth with en-masse retraction, closing loops are placed between the lateral incisors and canines, and connected to the C-implants by elastics.

Because intermaxillary elastics are not applied to the maxillary dentition, mesial movement of the maxillary arch and extrusion of the maxillary molars are avoided, and the incisors are not flared. This case report describes the distalization of the mandibular dentition to treat a dentalClass III malocclusion with a deviated midline by usingC-implants.

DIAGNOSISThe patient was a woman, aged 23 years 5 months, whose chief concern was protruding mandibular teeth. Her medical history was noncontributory, and occasional clicking of her temporomandibular joints (TMJ) was noted in her dental history.The pretreatment facial photographs show an acceptable facial profile, despite mild midface deficiency and slight mandibular prognathism.

The clinical Examination showed a Class III molar and canine relationship that was more significant on theright side. Other findings included an anterior edgeto-edge relationship, a midline discrepancy, mild mandibular anterior crowding, and mesial angulation ofthe mandibular posterior teeth. The lower midline wasnot coincident with the facial midline and was shiftedto the left by 2.5 mm.

The maxillary third molars and the mandibular right third molar were missing. There was only slight contact between the maxillary right second molar and the opposing tooth because of the Class III molar relationship.

The cephalometric analysis showed a skeletal Class III relationship with a high mandibular plane angle and a slightly retrognathic maxilla. The anterior facial height was slightly long relative to the posterior facial height. The incisor position and interincisal relationship were within normal limits except for the retroclined maxillary incisor. The patient was diagnosed with a skeletal Class I malocclusion with mild maxillary deficiency and a dental Class III relationship.

TREATMENT OBJECTIVESA mandibular premolar extraction plan would bea relatively simple and stable way to resolve the anteriorcrossbite. Complex treatment mechanics and manytooth movements would not be needed. However, thepatient did not want extractions (except for the thirdmolars) or changes to her facial appearance; she wanted only to correct the incisor relationship. Although the maxillary incisors were slightly upright, the patient requested that they not be allowed to move forward.Therefore, we rejected the premolar-extraction treatmentoption.

Based on the initial records and the patient’s desires,the treatment objectives were to distalize all mandibularteeth, improve the interincisal relationship to have normal overjet and overbite, shift the mandibular midline to coincide with the facial and maxillary midlines, andachieve Class I canine and molar intercuspal relationships. A conventional fixed appliance was prescribed.

TREATMENT ALTERNATIVESMaxillary advancement surgery was not a viable treatment option because the skeletal deficiency was not significant, and the patient was pleased with her facial appearance. Maximum anchorage and interarch elastics were discussed for en-masse movement of the mandibular dentition. She refused the interarch elastics because of their visibility. Her occasional clicking was also a matter of concern because it might lead to TMJ dysfunction symptoms during orthodontictreatment. Therefore, mandibular distalization with a C-implant in the posterior dentition and intra-arch elastics was the treatment of choice. After distal movement of the mandibular dentition, a full fixed appliance would be used in the maxillary dentition for finishing.

TREATMENT PROGRESSTwo C-implants, 1.8 mm in diameter and 8.5 mm long, were placed in the interdental spaces between the mandibular second premolars and first molars. Bone quality in the mandible was good, and the implants were loaded immediately. A 0.016-in NiTi initial archwire was used for leveling and distalization of the mandibular posterior dentition. Intra-arch elastics (1/4-in, 3.5 oz) were applied from the 0.7-mm-diameter stainless steel sliding jig to the neck of the C-implant for distalization of the mandibular second molar and anterior decrowding.

The maxillary dentition was not bonded initially becausethe dental and facial midlines were coincident,and no forward movement of the anterior teeth was desired.While the mandibular dentition was distalizing,drifting occurred. Therefore, a power chain was appliedto correct the midline

This applied an intrusive movement to the mandibular incisors because the NiTi archwire was not stiff, and elastics were applied from the incisors to the apically placed C-implant. To correct the anterior open-bite tendency from the force direction of the elastics, the mandibular archwire was changed to a 0.016 3 0.022-in NiTi archwire and then a 0.016 3 0.022-in stainless steel archwire with closing loops.

As the mandibular molars moved distally, the maxillarymolars were extruded. To correct the extrusion, the maxillary dentition was bonded for intrusion and leveling of the maxillary molars. A Class I molar relationship of the mandibular left dentition was achieved by using a sliding jig.

sliding jig

The mandibular right dentition was distalized 6 mm but still required further movement.The sliding jig was continuously applied to the mandibular first molar. The mandibular premolarscontinued to move separately

The closing loop of the 0.016 3 0.022-in stainless steel archwire was used as a hook for mandibular en-masse retraction.Distalization of the mandibular dentition and midlinecorrection took 18 months. The fixed appliances wereremoved, and retention was provided by maxillary andmandibular fixed retainers.

TREATMENT RESULTSThe active treatment period was 18 months. The patient’s facial profile was mostly unchanged.A Class I canine and molar relationship and normaltooth alignment with better midline coincidence,and normal overjet and overbite were achieved

The maxillary incisors moved forwardbslightly. The mandibular incisors were retracted considerably and extruded. The upper and lower lips moved very little. The interincisal angle increased as the mandibular incisors uprighted and the ANB angle remained unchanged. The posterior facial height anterior facial height ratio and the FMA were only slightly changed in spite of the significant mandibular molar distalization as seen in the superimposition.The patient was pleased with the treatment results.An ideal incisor relationship and Class I canine andmolar relationship were obtained.

Retention intraoral photographs at 26 months.

Skeletal Class III malocclusion correction using miniscrew

implantsJournal of the World Federation of Orthodontists 2 (2013) e151ee158

Diagnosis and etiologyA Hispanic woman aged 21 years, 10 months with a chiefcomplaint of an anterior crossbite presented for orthodonticTreatment. Facial analysis showed no gross asymmetries. A mesoprosopic and ovoid facewas observed. A straight to concave facial profilewas recorded in the lateral view.

Lateral cephalometric radiographic, panoramic radiographic, and cast models were used for the skeletal and dental diagnosis. Hypodivergent skeletal Class III pattern was observed, with an anterior mandibular functional shift of 0.5 mm. Analysis of the cervical vertebral maturation showed no growth remaining.

There was an anterior crossbite of her upper incisors, with a negative over jet of 0.5 mm in centric relationship (e1 mm in centric occlusion). Molars were in bilateral Class III occlusion. Posterior lingual crossbite of the upper left bicuspid and both upper second molars was observed.

Upper and lower incisors were excessively proclined, with mild maxillary spacing and mild mandibular crowding. The lower third molars were present, but noupper third molars were visible in the radiographs. Her upper centrals and laterals were abnormally shaped, with some incisal wear on the centrals.

Treatment objectivesThe treatment objectives were to: 1) improve facial profile by establishing normal over jet; 2) achieve Class I molar and canine relationship; 3) resolve the crowding in the mandibular arch; 4) close space in the maxillary arch; and 5) improve the transverse relationship between the upper and lower dental arches.

Treatment progressTreatment was started with placement of a banded lingual archon the mandibular second molars to maintain lower intermolarwidth during crossbite correction. Self-ligating brackets with .022-in slots and MBT prescription were bonded on all teeth but thelower second molars. A sequence of three pairs of archwires wasused in the upper and lower dentition. A .014-in nickel-titanium(Ni-Ti) archwire was used for initial alignment, followed by0.019 0.025-in Ni-Ti archwires and 0.019 0.025-in stainlesssteel archwires.

After placement of the lower stainless steel archwire, the third molars were extracted. Then two 6-mm MSIs were placed buccally between the mandibular second premolars and the mandibular first molars. The MSIs were placed close to the first molar mesial root, to allow for as much distalization as possible. Indirect anchorage was initially used to distalize the lower first and second molars into the extraction site of the third molar.

This was done by tying a stainless steel ligature from the MSIs to the lower premolars and placing open Ni-Ti coil springs mesial and distal to the first molars. Although no distal force was applied to the lower incisors from the MSIs at this time, mild over jet was achieved with the use of Class III elastics for 2 months, elimination of 0.5-mm anterior shift, and changing the upper arch form from square to ovoid.

After obtaining a half-step Class II molar relationship, powerarms were placed between the lower canines and the lower firstpremolars. Direct anchorage was used by placing a closed Ni-Ti coil spring from the MSIs to the power arms to distalize the lower incisors, thus preventing additional flaring of the upper incisors. The power arms allowed better bodily movement due to theline of action being closer to the center of resistance of the anterior teeth.

Detailing and finishing (bends and individual torque) were performed to achieve better intercuspation after Class I molar and canine relationships were observed. After 2 years and 4 months of treatment, the fixed appliances and MSIs were removed and retention was provided by a maxillary wraparound retainer andmandibular fixed retainer bonded to the canines.

Results The patient’s chief complaint was addressed with correction of the anterior crossbite, and she was pleased with the overall treatmentresults. The lateral photograph and cephalometric radiograph showed improvement of the profile due to slight upper lip advancement. There were no significant skeletal changes with treatment.

Skeletal Class III pattern showed slight improvements.The maxilla showed no anteroposterior changes. The mandibleshowed slight reduction of the protrusion at B point (decrease insella, nasion, point B angle). The reduction of dentoalveolarmandibular protrusion improves the maxillomandibular relationship due to a greater point A, nasion, point B angle and smaller Wits appraisal. The vertical dimension showed minimal changes.

Ideal incisor relationship was obtained, and a proper cuspid andmolar Class I relationship was achieved. The upper and lower teeth showed changes in an anteroposterior position. The upper incisors were advanced and proclined more than anticipated. Class III elastics, 17 torque brackets on the upper centrals, and a change to a more ovoid arch form likely contributed to the upper incisor flaring.

The lower incisors were retracted, with some retroclination and slight extrusion. Mandibular incisors were initially retracted more than 3 mm, resulting in excess over jet. Class II elastics were needed (2 months) to correct the resultant over jet.Upper molars were mesialized approximately 1.5 mm, and maxillary space was closed. There was no significant change in the vertical dimension of the upper teeth. The lower molars were distalized approximately 3 mm (4 months of Ni-Ti coil spring use), with slight distal inclination, helping to correct the mild crowding as well the anteroposterior relationship.

Wraparound retainers for the maxillary teeth and fixed retainers to the lower anterior teeth were delivered. The patient was referred to her general dentist for continued care and reshaping of the upper incisors. Final records showed acceptable results.

C-Orthodontic Microimplant for Distalization of MandibularDentition in Class III Correction

Angle Orthodontist, Vol 75, No 1, 2005

A 16-year-old-male presented with the chief complaintof missing lower anterior teeth, lower anterior protrusion,and eagerness for an attractive smile. He had a history ofmissing lower central incisors because of a traffic accidentat 7 years of age. No space maintainer was used duringgrowth. The extraoral examination revealed the facial characteristics of a mild Class III lower anterior protrusion patient with a deep labiomental sulcus and a prominent and everted lower lip with an increased interlabial gap.

The intraoral examination revealed a severe asymmetrical dental Class III malocclusion with an anterior shallow overbite and a negative overjet. There was no occlusal centric relationship discrepancy on closure. Skeletal and dentalcharacteristics showed a slightly prognathic mandible, protruded upper incisors, and procumbent lower incisors.

The temporomandibular joint function was normal. The maxillary midline was coincident with the facial midline. However, the mandibular midline did not coincide with the facial midline due to the lost space in the missing lower anterior dentition.

The radiographic examination revealed that the patienthad a concave profile with an ANB angle of 21.58, a slightlyprognathic mandible (SNB angle 838, SN-Pg angle 848,and Wits appraisal 29 mm), a high mandibular plane (FMA298), and protrusive upper incisors (interincisal angle 1168,maxillary incisor to NA angle 338, maxillary incisor to NAdistance 10 mm) (Figure 4). The pretreatment panoramicradiograph illustrated excellent periodontal support and thepresence of impacted third molars.

Treatment planThe patient requested only conventional orthodontictreatment and did not want his upper front teeth to be protruded any further. Based on the results of the cephalometric and study model analyses, the treatment objectives were to establish a Class I molar and canine relationship, create an ideal overjet and overbite, improve the occlusal interdigitation, regain space to allow an esthetic dental restoration of the lower anterior edentulous area, and improve the facial balance.

However, en masse retraction of the full lower dentition by conventional orthodontic treatment could cause the reactive extrusion of the upper anchor teeth and upper anterior protrusion with a change in the upper midline. Therefore, the treatment strategy was to place a Cimplant in the upper molar area and to apply Class III mechanics between lower dentition and upper C-implant using Class III elastics to correct the Class III molar and canine relationship.

Treatment progressTwo C-implants were implanted in the interdental spacesbetween the upper second premolars and first molars. Afterincision of the mucosal area, drilling was carried out at1500 rpm of drill speed and 15 Ncm of drill pressure withprofuse irrigation with isotonic saline solution. The 1.5-mmdiameter guide drill was selected when drilling to depth in cortical bone. The screw part was placed clockwise into the prepared site using internal and external sterile saline cooling.

After an 8-week healing period, the head part of C-implantwas assembled into the screw part by lightly tapping witha small mallet 1 to 2 times. Immediate loading is possible,mainly in areas where dense bone is located and whereprimary stability can be achieved.

Treatment was initiated with the leveling and distalizationof the lower posterior dentition. Because of the patient’sdental and skeletal problems, no bonds were placed on the maxillary anterior and right posterior teeth. However, brackets were placed on the upper left posterior teeth, followed by the placement of a segmented 0.022 3 0.028 inch preadjusted arch wire appliance for intrusion of the upper left second molar.

Progress intraoral photographs: (A) during sliding jig treatment and (B) after full distalization of lower dentition.

The lower third molars were all removed. The patient was instructed to wear Class III elastics as long as possible to move the lower dentition distally.The missing lower anterior space was almost completelyregained after 12 months of active tooth movement. The fixed appliances were removed, and a tooth positioner was used for 1 month for finishing. The retention was provided by an upper fixed retainer and removable lower Hawley retainer.

Treatment results and discussionAfter treatment, a Class I molar and canine relationshipwith midlines coincident, correct tooth position, and properalignment were present. Ideal overjet, overbite, and facialbalance were also achieved, and the incisors were not procumbent.

The lower dentition was notably distalized 5 mm on the left and 2 mm on the right side. Cephalometric analysis showed a slight downward and backward mandibular movement as well as an asymmetric distalization of the lower dentition.

The FMA changed slightly from 29 to 30 degree. The backup with the C-implant hook can be assumed not to change the position of the upper molars, which minimized any increasedsteepness of the mandibular plane. However, the intrusiveforce on the upper left second molar using a sectional archwireis believed to have caused a slight extrusion of the upper molars.

We should have used the C-implant as an anchorage appliancefor intrusion of the upper left second molar simultaneouslywith lower distal movement. The occlusal plane was not changed significantly after treatment because of extrusion of both the upper and lower posterior teeth during distal movement (SN to OP angle 118 to 138). The upper incisors were slightly protruded (FH-U1 angle 1258–1278, maxillary incisor to NA distance 10–11 mm, maxillary incisor to NA angle 338–378). The lower incisors were uprighted and retracted. In this case, lower lateral incisors were used as the landmarks for deciding the lower incisor position because of the missing lower central incisors (IMPA 918–838, FMIA 608–678, mandibular incisor to NB distance 7 mm to 5 mm, mandibular incisor to NB angle 308–238).

The lips were competent in repose (upper lip to E-plane 0 mm to 0.5 mm, lower lip to E-plane 3 mm to 0.5 mm). The interincisal angle was improved to a normal range (1168–1218). The ANB changed a little during treatment (SNA 828–82.58, SNB 838–838, Wits appraisal 29 mm to 25 mm). The posterior/anterior facial height ratio was slightly increased after treatment (91/142 mm, 64.2% to 93/144 mm, 64.6%).The entire lower dentition was distalized successfully byusing the C-implant as a hook for elastics. The treatmentresult was quite acceptable, and the patient was pleasedwith the final treatment results despite the space for theanterior restoration being slightly deficient.