A Professional Courtesy of: James E. Metz, D.D.S.General Dentist

Diplomate, American Board of Dental Sleep Medicine

1271 E. Broad StreetColumbus, Ohio 43205

(614) 252-4444 • Fax: (614) 252-6474www. ColumbusDentistry.com

Memberships:American Dental Association • Ohio Dental Association • Columbus Dental Society

American Academy of Restorative Dentistry International Academy of Gnathology • American College of DentistsEuropean Academy of Dental Sleep Medicine • American Academy of Dental Sleep Medicine • American Academy of Sleep Medicine

Implants and Treatment PlanningImplant prosthodontics is limitless in its scope for rehabilitation. Wliether a treatment requires a definitive or interim prosthesis, itis the expertise and guidance of the prosthodontist that positively affect the outcome. This issue of Report on Prosthodonticspresents a potpourri of treatment protocols that a prosthodontist is best suited to provide.

A Simplified Approach toFixed Metal-ceramicReconstructions

Restoring the edentulous patient with an implant-supported fixed complete denture prosthesis is achallenging procedure. Fixed metal-ceramic re-

constructions are inherently different from fixed com-plete dentures or implant overdentures. From a prostho-dontic perspective, there are 3 phases of treatment forthese types of rehabilitations:

1 diagnosis and treatment planning, followed byimplant placement;

"2 clinical assessment of post-implant placement; and

3 design of the definitive prosthesis.

Simon and Marchack from the University of SouthernCalifornia clearly defined these phases of therapy, focus-ing on the importance of phase 2 and the clinical evalu-ation of the tentative treatment plan through evaluation

of the provisional prosthesis. It is this phase that sets theexperienced practitioner apart from the novice.

Often the inexperienced clinician will choose the tradi-tional approach of provisionalization with a removableprosthesis and then move directly to a definitive fixedrestoration. The inherent problem with this approachis that the contours of aprovisional removableprosthesis are vastly dif-ferent from those of afixed prosthesis; thepatient's esthetics, pho-netics and lip supportare significantly differentwithout denture flangesand palatal coverage. Toovercome some of thesedifferences, the authorssuggested provisionaliza-tion with a fixed pros-thesis to evaluate the

Inside this issue:Immediate Function UsingZygoma Implants

Giiigival-colored CeramicsIn Bone-deficientRegions of the Jaw

Modified CompleteDentures as an InterimCement-retained Prosthesis

Endodontic vs ImplantTreatment Outcomes

proposed prosthesis, Summer 2009

determine the need for modification to the proposed designand provide information to be communicated to the dentallaboratory. They described a technique to convert an interimdenture to a screw-retained fixed implant-supported provi-sional restoration, developing the embrasure and soft-tissuecontours. The restoration may then be used to evaluate thepatient's speech and ability to maintain hygiene, the need forconnective tissue grafting, the use of tissue-colored restorativematerials, the existence of any nocturnal parafunctional activ-ity and the determination of the appropriate fixed restorationocclusal scheme. Once the provisional restoration is finalized,it can be duplicated and sent to the laboratory to provide a3-dimensional blueprint.

This study clearly demonstrated the special considerationsthat must be taken into account when creating and placingesthetically demanding fixed metal-ceramic implant-sup-ported prostheses. Limitations of the traditional removableprovisional restoration can be overcome when a patient istreated using this approach. Not only is the prosthodontistable to make critical decisions with regard to the prosthesisdesign, but he or she can use the information obtained tomaximize the treatment outcome by better communicationwith the dental laboratory.

Simon H, Marchack CB. A simplified approach to implant-supported

metal-ceramic reconstruction.] Prosthet Dent 2004;91:525-531.

Immediate FunctionUsing Zygoma Implants

Bone resorption in the posterior maxilla is quitecommon.Various techniques have been developedto treat the atrophic maxilla with dental implants.

Grafting with various materials is one example. However,these procedures typically result in delayed protocols inwhich grafting is performed first, followed by increasedhealing time for the graft as well as after implant surgery,ultimately resulting in longer treatment times and delayof the fabrication of the prosthesis. The zygoma implant,developed to deal with this situation, has proven to be anexcellent alternative to conventional dental implants.

In a retrospective study, Davo et al from the InternationalMedimar Hospital, Spain, evaluated the survival rate ofzygoma implants (Branemark System; Nobel Biocare AB,

Table 1. Size and number of zygoma implants placedin 18 patients

Size of implants(mm)

Number ofimplants placed

30 0

35

40

45 13

47.5

50 12

Total 36

Goteborg, Sweden) placed using an immediate loading pro-tocol for 18 consecutively treated patients with atrophicmaxillae. The inclusion criteria included

• the need for complete rehabilitation of the edentulousmaxilla and

• the need for sinus grafting, wide implants or pterygoidimplants in the posterior maxilla.

The distribution of implants is shown in Table 1. The au-thors' aim \vas to evaluate the survival rate of 36 imme-diately loaded zygomatic implants after a minimum of6 months follow-up.

One hundred percent of the zygomatic implants survivedover a mean follow-up of 14 months. Due to the difficultyin radiographic analysis of this area, only clinical survivalwas reported.

Within the limitations of this study, these data show thatzygoma implants, in combination with 2—5 anterior con-ventional dental implants placed in atrophic maxillae, canbe loaded immediately to support a fixed screw-retained,acrylic resin implant denture. Because of the short evalua-tion period and the small sample size, further research inthis area is needed. However, the preliminary results fromthis study are promising. It should be noted that the pros-thetic techniques of this treatment protocol are very exact-ing and require the skill of the provider.

Davo R, Malevez C, RojasJ. Immediate function in the atrophicmaxilla using zygoma implants: a preliminary study.] ProsthetDent 2007;97:S44-S51.

Summer 2009

Gingival-colored Ceramics inBone-deficient Regions ofThe Jaw

Aprosthodontist has the ability to look at a situationfrom various standpoints and develop alternativetreatment options to address complex, esthetically

demanding situations. As clinicians, we often see patientswho exhibit loss of soft tissue and supporting bone. Manytimes, the lost structures can be re-created with surgicalintervention. However, there are times when surgicalprocedures are not feasible or have limited results thatmay not totally resolve the problem; therefore, the pa-tient's clinical presentation may compromise the estheticoutcome. Restoration of the anterior dentition using den-tal implants can be technically demanding when conditionsare ideal; loss of the supporting hard- and soft-tissue struc-tures further diminishes the clinician's ability to obtain op-timal results. The use of gingival-colored ceramics offers aneffective method of developing esthetics when reconstruc-tive surgery is not an option.

Polack and Mahn, private practitioners from Virginia, re-ported on a patient's treatment that created a prostheticsolution to this compromised state. The 43-year-old, non-smoking male patient presented with missing mandibularincisors, which resulted in a narrow, irregular residual alve-olar ridge deficient vertically and horizontally. A diagnosticwax-up revealed the expected esthetic problems associatedwith unnaturally long teeth. A minimal amount of calcifiedbone allograft was used to allow implant placement 5 weeksafter the initial extraction.

The prosthetic treatment plan called for replacing the man-dibular incisors and the hard and soft tissues with a 4-unitfixed partial denture (FPD) using gingival-colored ceramic.The study detailed the prosthetic treatment of establishingthe prosthesis contours and determining the amount of gin-gival-colored porcelain required through a provisionaliza-tion process, and the use of a silicone matrix developedfrom the provisional to guide the fabrication of the defini-tive FPD.

The authors presented several prosthetic treatment alterna-tives, including a conventional FPD and removable partialdentures. These options would have compromised eitherthe esthetics or the stability of the prosthesis, or both. The

ability of the gingival-colored ceramic to restore interden-tal papilla and gingival tissues that otherwise could not bereplaced make it a viable treatment alternative to compro-mised esthetics. The key to its predictable success, however,is the thorough treatment planning and execution by theprosthodontist.

Polack MA, Mahn DH. The aesthetic replacement of mandibular incisors

using an implant-supported fixed partial denture with gingival-colored

ceramics. Pract Proced Aesthet Dent 2007;19:597-603.

Modified CompleteDentures as an InterimCement-retained Prosthesis

Advances in implant dentistry have afforded thepatient and the prosthodontist many treatmentalternatives. One such is whether to immediately

place the definitive or provisional restorations. Althoughimmediate loading has proven to be successful, many clini-cians have chosen to load provisionally, allowing for posi-tional modification from the proposed implant site, sitesoft-tissue changes post-healing and the ability to developsoft-tissue contours.

Wat et al from the University of Hong Kong, China, sum-marized a patient treatment in which a mandibular com-plete denture was converted to a cement-retained prosthe-sis immediately post-implant placement. The flanges of therelined denture were contoured for easy cleaning and pro-visionally cemented. Table 2 lists the criteria needed formaking such a decision.

Table 2. Clinical criteria for patient selection

Patient should be medically fit for implant surgery andintravenous sedation.

The bone quality and quantity of the anterior mandibleshould be adequate for the insertion of 4—6 implants.

The jaw relation of the existing complete dentures shouldbe correct.

The oral surface of the denture and tooth positions shouldbe satisfactory.

There should be sufficient bulk in the mandibular completedenture to provide room for the implant abutments.

Summer 2009

Although not shown in this study, the prosthesis could havebeen further contoured to develop a profile for the definitiverestoration. In all likelihood, most prosthodontists would takethis technique a step further by developing the framework orpontic form. However, this method does provide an inexpen-sive method to provide immediate function, satisfy esthetics,splint the dental implant and aid in patient comfort with afixed provisional prosthesis. Meticulous planning and execu-tion are required.

Wat PYP, ChowJKF, Chu PCS, Chow TW. Modified mandibular com-

plete denture as an interim implant-supported, cement-retained prosthesis:

a clinical technique. Clin Implant Dent Relat Res 2001',9:1-5.

Endodontic vsImplant Treatment Outcomes

D entists must make treatment decisions on a dailybasis. As implant therapies have become morecommonplace, decisions must be made whether to

endodontically treat a tooth or to extract it and place animplant. The aim of both implant and endodontic therapyis to facilitate rehabilitation of patients' masticatory systems.

Endodontic therapy is intended to retain teeth. The need forendodontic therapy is most commonly due to caries, but mayalso be due occasionally to traumatic injury. Implant therapyis intended to replace missing teeth and addresses tooth lossmost commonly caused by periodontal disease, althoughcaries and trauma may also be causes. White et al from theUniversity of California, Los Angeles, reviewed the endo-dontic and implant literature to determine differences be-tween the therapies that can assist dentists in making treat-ment decisions.

Outcome data was inconclusive and not suited for directcomparison of the 2 therapies. Even data, such as survivalrate, could not be compared because implant or implantprosthesis survival rate is evaluated by a 2-tier "success orfailure" approach, whereas endodontic therapy is a 3-tier"success, failure or uncertain" approach. As a result, out-come information cannot be used to derive treatment ma-trices. To date, rigorous cost and benefit comparisons havenot been made nor have consensus statements been devel-oped that provide the detail needed to guide the dentist.

Without the information needed to make a direct compar-ison between endodontic and implant therapies, prognosticfactors can be helpful in the decision-making process. Pre-operative diagnosis, extent of existing disease and degree oftooth loss are factors that can have an impact on the long-term clinical success of a tooth requiring endodontic ther-apy. There is a long list of factors that may affect implantsuccess, including

• medical and oral health;

• bone quality and quantity; and

• prosthesis type.

Identification and quantification of prognostic indicatorswould be a valuable tool in formulating standard treatmentprotocols and developing individual treatment plans. Untillong-term, clearly defined, outcome-measured studies eval-uating the clinical performance of endodontic and implanttherapies are completed, the patient must rely on the ex-pertise of the clinician as a guide to making treatment-plan-ning decisions.

White SN, Miklus VG, Potter KS, et al. Endodontics and implants, a cata-log of therapeutic contrasts.} Evid Base Dent Pract 2006;6:101-109.

In the Next Issue:Pretreatrnent preliminary screening for edentulousmaxilla

line of the edentulous maxilla

! Retrospective study of the Marius bridge

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