siu university at sea 07-22-13...

Mechanical Considerations for Implant Assisted and Supported Prostheses in the

Edentulous Patient

Dr. Steven J. LoCascioKnoxville, TN

Southern Illinois UniversitySchool of Dental Medicine

University at SeaJuly 22, 2013

Heydecke, G et al.

Clin Oral Impl Res 2003; 14:125-130

Within-Subject Comparisons of Maxillary Fixed and Removable Implant Prostheses:

Patient Satisfaction and Choice of Prostheses

Patient ratings of general satisfaction (as compared to natural teeth, comfort, ability to speak, stability, aesthetics, ease of cleaning, occlusion, and ability to chew seven index foods) were measured with VAS. Information about the patientʼs physical and psychosocial function and general health were measured with category scales (CAT).

Dental implants provide patients with restorative options for the edentulous maxilla. Both fixed and removable prostheses can be attached to the edentulous maxilla, but the efficacy of different designs has not been determined. In this two-session within-subject crossover trial we compared maxillary implant retained fixed prostheses with removable implant overdentures opposed by mandibular implant-supported overdentures. Sixteen patients, who had previously received mandibular implants, entered the study and received four to six maxillary implants. After dropouts as a consequence of a lack of osseointegration and general health problems, 13 remained. Of these, five received the removable prosthesis first and eight the fixed prosthesis. After 2 months, the prostheses were exchanged and the second was also worn for 2 months. Psychometric measurements of general satisfaction with the prostheses as well as comfort, ability to speak, stability, esthetics, ease of cleaning and occlusion were obtained once each prosthesis had been worn for 2 months. Chewing ability was assessed for seven types of food. Removable long-bar overdentures received significantly higher ratings of general satisfaction than fixed prostheses (P Ω 0.003). Patients also rated their ability to speak and ease of cleaning significantly better with the removable overdentures. Nine patients chose to keep the removable prosthesis and four preferred to keep the fixed prosthesis. The results suggest that maxillary removable overdentures on multiple implants may provide patients with better function than fixed prostheses. Heydecke G, Boudrias P, Awad MA, de Albuquerque Jr RF, Lund JP, Feine JS. Within subject comparisons of maxillary fixed and removable implant prostheses: Patient satisfaction and choice of prosthesis.

Heydecke, G et al.


• Patients previously treated with mandibular implants entered the study

• 4-6 maxillary implants were placed- 1/2 of patients received

removable prostheses 1st- 1/2 of patients received fixed

prostheses 1st- after 2 months the prostheses

were exchanged- the 2nd prostheses were also

worn for 2 months



Heydecke, G et al.


• Patient ratings were measured with VAS and category scales (CAT)

• Psychometric measurements:- general satisfaction- comfort- ability to speak- stability- aesthetics- ease of cleaning- occlusion- chewing ability



Heydecke, G et al.


• Removable long-bar OD’s received higher ratings than fixed prostheses

• More than 2X the number of patients chose to keep the removable overdenture



Heydecke, G et al.


The results of this investigation suggest that maxillary removable overdentures on multiple implants may provide patients with better function than fixed prostheses.



de Albuquerque, R et al.


Within-Subject Comparison of Maxillary Long-Bar Implant-Retained Prostheses With and Without Palatal Coverage:

Patient Based Outcomes

This crossover trial was to measure differences in patient satisfaction with long-bar implant overdentures with and without palatal coverage. 16 totally edentulous french speaking patients all wearing CD/CDʼs (5 year wearers). 4 implants were placed in the mandible and maxilla without bone augmentation. study included 4 data gathering periods. 1st: new CD/CD 2nd: 4 max and 4 mand implants with CD/fixed 3rd: CDODwP/fixed 4th: CDODwoP/fixed Patient comparison of treatmetns were evaluated with VAS and categorical scales There were no statistical differences in ratings of general satisfaction with the maxillary prostheses during the four periods of the trial except for STABILITY b/t periods 2 and 3 when max od with palate was rated higher than conventional max cd. Neither max od design with or without palate performed better than a new max conventional cd.Although maxillary implant overdentures are used in oral rehabilitation, different designs have not been compared previously in clinical trials. This crossover trial was designed to measure differences in patient satisfaction with maxillary long-bar implant overdentures with and without palatal coverage opposed by a fixed mandibular implant-supported prosthesis. Data were also gathered on new conventional dentures and onmaxillary conventional dentures opposed by mandibular fixed prostheses. Sixteen participants were selected from a population wearing conven-tional dentures. Fifteen received new upper and lower dentures out). Four implants were placed in the maxilla and mandible (2 drop-outs).A mandibular fixed prosthesis was inserted in 13 participants, who were then divided into 2 groups. One group (nΩ7) received long-bar overdentures with palate, then long-bar overdentures without palate. The other group (nΩ6) received the same treatments in the reverse order. Mastica- tion tests and psychometric evaluations using Visual Analog Scales and Categorical Scales were perfor med throughout the study. General satisfaction was very high with both maxillary implant-supported prostheses, as were ratings of almost all psychosocial and functional variables. There were no significant differences between treatments, suggesting that patients are equally satisfied with long-bar overdentures with and without palate when these are opposed by mandibular fixed prostheses. How- ever, the ratings given to the maxillary implant prostheses were not significantly higher than for new conventional maxillary prostheses. suggests that maxillary implant prostheses should not be considered as a general treatment of choice in patients with good bony support for maxil-lary conventional prostheses.



• Crossover trial to measure differences in patient satisfaction with long-bar OD’s w/ and w/o palatal coverage

• CD/CD patients (5yrs)

• 4 implants placed in max and mand

• 4 data gathering periods:1) New CD/CD 2) CD / Fixed3) CDODw/P / Fixed4) CDODw/oP / Fixed


• Patient ratings were evaluated with VAS and category scales (CAT)

• No statistical differences in ratings of general satisfaction with the maxillary prostheses during the 4 trial periods

• Neither maxillary OD design w/ or w/o palatal coverage performed better that a new maxillary conventional CD






The ratings given to the maxillary implant prostheses were not significantly higher than for new conventional

prostheses.

This suggests that maxillary implant prostheses should not

be considered as a general treatment of choice in patients

with good bony support for maxillary conventional

dentures.


Where do we begin?

Treatment PlanningThe Edentulous Patient

4. Hybrid Denture

3. Implant Supported Overdenture

2. Implant Retained Overdenture

1. Conventional Denture

5. Immediate Occlusal Loading

Edentulous

Mandible

Clinical Scenarios

5. Immediate Occlusal Loading




4. Fixed (C & B)

Edentulous

Maxilla

Clinical Scenarios

4. Hybrid Denture




Х

Edentulous

Mandible

Clinical Scenarios

Classification of

Implant Overdentures

Implant Retained / Tissue Supported

“Implant Assisted”

Implant Retained / Implant Supported

“Implant Supported”

Ettinger R, / Jakobsen, J

Community Dent Oral Epidemiol 1997; 25:223-227

A Comparison of Patient Satisfaction and Dentist Evaluation of Overdenture Therapy


1. Appearance2. Retention

Best Predictor of Satisfaction

It has been argued that the retention of some teeth in the jaws as overdenture abutments prevents negative feelings about the loss of natural teeth. This study set out to evaluate how satisfied a group of patients were with wearing overdentures, and to compare their subjective evaluations with those of a dentist using objective criteria to examine the prostheses. A questionnaire was developed using questions adapted from several other studies. It was pretested, modified and used on all patients who were members of a longitudinal study of overdentures that started in 1974, and who returned on recall. At the end of 9 months, 101 subjects had completed the questionnaire and examination. The mean age of the patients was 65.9 years with an age range of 35 to 88 years. There were 68 men and 33 women in this study and 62 of them were satisfied with their dentures; 33 were satisfied, but felt they had some faults. Only 6 were unhappy about wearing the overdentures. The average length of time the dentures had been worn was 6.9 years, with a range of 1 to 15 years. The most frequent complaints were loss of retention (65.4%) and discomfort (62.2%) of the mandibular dentures. A number of correlations were evaluated and some significant relationships were found between dentist and patient evaluation of the dentures. The best predictor of patient satisfaction with denture wearing was the patient's perception of retention and appearance. In the maxilla the patient's ability to chew and the dentist's evaluation of occlusion were also significant predictors. In the mandible the only other factors apart from retention and appearance were patient comfort and age.

Overdenture RetentionMechanisms / Attachments

3. Locking Bar

2. Bar

1. Stud• Radicular

• Intraradicular

Non-Resilient• Solid and Rigid -- ex. Beyeler

• Solid, Rigid, and “Lockable” -- ex. T-Bloc

Resilient• Vertical -- ex. Swiss Hinge

• Hinge -- ex. SwissMini

• Vertical and Hinge -- ex. Dalbo

• Rotational, Vertical and Hinge -- ex. ASC 52

• Universal -- ex. ORS

Attachment Classifications

Attachment Studies

Chung, K et al.

J Prosthodont 2004; 13:221-226

Breeding, L et al.

J Prosthet Dent 1996; 75:570-573

Williams, B et al.


Evtimovska, E et al.


Attachment Retentive Value Studies

Purpose: The aim of this study was to compare the retention characteristics of various overdenture attachment systems commonly used to retain overdentures to dental implants. Materials and Methods: An edentulous mandibular model was constructed incorporating 2 parallel 4.0 mm × 13 mm Branemark implants placed in the canine regions. Attachments were embedded in a metal-reinforced experimental overdenture designed to be dislodged from the model by a universal testing machine. Tensile dislodging force was applied to the overdenture at a cross-head speed of 50 mm/min. Five overdentures were constructed for each of the attachment systems. The attachments evaluated were the Hader bar & metal clip, Locator LR pink, Locator LR white, Spheroflex ball, Shiner magnet, Maxi magnet, Magnedisc magnet, ERA white, and ERA gray. Each apparatus was tested with 5 specimens per attachment system. Peak load-to-dislodgement wasmeasured. Analysis of variance and Scheff´ e multiple comparison tests were applied to the data with α ≤ 0.05 level of significance. Results: Peak load-to-dislodgement for all attachment systems ranged from 3.68 ± 1.32 N to 35.24 ± 1.99 N. Strain-at-dislodgement, calculated from stress-strain curves, ranged from 0.78 ± 0.20% to 2.78 ± 0.5%. The ERA gray attachment demonstrated the greatest retention, with a peak load-to-dislodgement of 35.24 ± 1.99 N, and a relatively low strain-at-dislodgement of 1.64 ± 0.09%. Less retention was recorded for the Locator LR white, Spheroflex ball, Hader bar & metal clip, and ERA white systems. The Locator LR pink attachment demonstrated still less retention with a load-to-dislodgement of 12.33 ± 1.28 N. Significantly high strain-at-dislodgement was recorded for the Hader bar & metal clip and Locator nylon attachment systems. The lowest dislodging loads and strains were recorded for the Shiner magnet, Maxi magnet, and Magnedisc magnet attachments. Conclusions: Results suggest that the attachment systems evaluated may be grouped into high (ERA gray), medium (Locator LR white, Spheroflex ball, Hader bar & metal clip, ERA white), low (LocatorLR pink), and very low (Shiner magnet, Maxi magnet, Magnedisc magnet) retention characteristics.

Evtimovska, E et al.


The Change in Retentive Values of Locator Attachments and Hader Clips Over Time

ABSTRACTPurpose: The aim of this study was to examine early changes in retentive values of implant overdenture attachments during multiple pulls.Materials and Methods: Two implant attachment systems (Hader bar and clip, Locator system) were used in this study. The experimental groups were divided into yellow Hader clips, white Locator attachments, and green Locator attachments. Each group consisted of 21 matrix attachments. The attachments were placed into a custom-made acrylic resin block seated passively on another acrylic block containing a Hader bar or two Locator abutments with different angulations. Each attachment was subjected to 20 consecutive pulls using a universal testing machine. The peak load-to-dislodgement of the attachments after each pull was documented, and the percent reduction of the peak load-to-dislodgement was calculated. One-way ANOVA and Tukey's honestly significant difference test were used for data analyses. A p≤ 0.05 was considered significant.Results: There was a significant difference in the percent reduction in peak load-to-dislodgement between the attachments after the first pull (p= 0.005) and after the final pull (p= 0.0001). The yellow Hader clips exhibited the least percent reduction in peak load-to-dislodgement (6.50 ± 3.59%) after the first pull, followed by the white Locator attachments (8.60 ± 4.42%); the green Locator attachments exhibited the greatest reduction (11.05 ± 4.94%).Conclusion: The results of this in vitro study demonstrate that retentive values of the Locator attachments are reduced significantly after multiple pulls. Although this reduction might not be noticeable to the patient, it is recommended that the clinician place and remove the overdenture multiple times before delivery.

Retentive values of the Locator attachments are reduced significantly after multiple pulls.

ABSTRACTPurpose: The aim of this study was to examine early changes in retentive values of implant overdenture attachments during multiple pulls.Materials and Methods: Two implant attachment systems (Hader bar and clip, Locator system) were used in this study. The experimental groups were divided into yellow Hader clips, white Locator attachments, and green Locator attachments. Each group consisted of 21 matrix attachments. The attachments were placed into a custom-made acrylic resin block seated passively on another acrylic block containing a Hader bar or two Locator abutments with different angulations. Each attachment was subjected to 20 consecutive pulls using a universal testing machine. The peak load-to-dislodgement of the attachments after each pull was documented, and the percent reduction of the peak load-to-dislodgement was calculated. One-way ANOVA and Tukey's honestly significant difference test were used for data analyses. A p≤ 0.05 was considered significant.Results: There was a significant difference in the percent reduction in peak load-to-dislodgement between the attachments after the first pull (p= 0.005) and after the final pull (p= 0.0001). The yellow Hader clips exhibited the least percent reduction in peak load-to-dislodgement (6.50 ± 3.59%) after the first pull, followed by the white Locator attachments (8.60 ± 4.42%); the green Locator attachments exhibited the greatest reduction (11.05 ± 4.94%).Conclusion: The results of this in vitro study demonstrate that retentive values of the Locator attachments are reduced significantly after multiple pulls. Although this reduction might not be noticeable to the patient, it is recommended that the clinician place and remove the overdenture multiple times before delivery.

Trakas, T et al.

Implant Dent 2006; 15:24-34

Attachment Systems for Implant Retained Overdentures: A Literature Review

Abstract:This article presents a comparison between different attachment systems used to retain and support maxillary and mandibular overdentures in completely edentulous patients. A literature review based on a MEDLINE search limited to English-language articles published from 1988 to the present was performed, and a large number of attachments available in the dental market were reviewed with regard to several factors, including: (1) implant survival rate, (2) marginal bone loss, (3) soft tissue complications, (4) retention, (5) stress distri-bution, (6) space requirements, (7) maintenance complications, and (8) patient satisfaction. These factors are considered essential for the successful outcome and good long-term prognosis of the prostheses. Selection criteria previously published in the literature are discussed as well. Product names and manufacturers are mentioned only if related to attachment systems, as they are cited in the original articles.

Trakas, T et al.


• Cost

• Retention needed• Pain caused on soft tissue• Amount of available bone

• Oral hygiene considerations• Patient’s social status• Patient’s expectations• Maxillomandibular relationship

• Status of antagonistic jaw• Interimplant distance

Selection Criteria


Trakas, T et al.


Selection Criteria

• Cost

• Retentive values

• Interimplant distance

• Interarch restorative space


Implant Assisted Designs

Mandible vs. Maxilla

Stressbreaking

&

Fulcrums


-- splinting with more than two implants

-- prosthesis design and accuracy

-- stressbreaking and fulcrum lines

When using attachments with implant assisted overdentures always consider:


The Edentulous Mandible


Non-Splinted Implants


The fulcrum line is a line through the stud attachments.

The fulcrum line should ideally be located perpendicular to the rotational path of the denture

prosthesis for maximum stress breaking.

The fulcrum line is a line through the stud attachments.

The anatomical position of two implants is critical in allowing maximum stress breaking.

The fulcrum line is a line through the stud attachments. What about four non-splinted implants?

What about four non-splinted implants?


C = CompressionT = Tension

XX

T TC C

T TC C


C = CompressionT = Tension

X X


Splinted Implants

“Simple”Bar AttachmentBar Attachment

Vertical&

Rotational Resiliency

Resilient Bar

Non-resilient bars are solid attachments and do not allow for vertical or rotational resiliency.

Non-Resilient Bar

Non-resilient bars are not indicated for use with implant assisted overdenture designs.

Are there any indications to splint two implants together in the anterior mandible?

1. To position the fulcrum line perpendicular to the rotational path of the denture for maximum stress breaking

2. To cantilever the bar anteriorly to prevent rotational dislogement of the posterior aspect of the denture during incising

3. To angle correct

4. To accomplish any combination of the above

Are there any indications to splint two implants together in the anterior mandible?

The Edentulous Maxilla


Non-Splinted vs. Splinted Implants


Cavallaro, JS / Tarnow, DP

Int J Oral Maxillofac Implants 2007;22:808-814

Unsplinted Implants Retaining Maxillary Overdentures with Partial Palatal Coverage:

Report of 5 Consecutive Cases



• 5 consecutive patients treated

• 25 textured-surface implants placed- 2 patients -- 4 loaded

implants- 1 patient -- 5 loaded implants- 1 patient -- 6 loaded implants- 1 patient -- 6 implants (4 loaded)

• 12 - 48 months postloading followup

• Stud attachments maintained retentive force for at least one year



All unsplinted implants maintained osseointegration to retain removable overdenture prostheses with limited palatal

coverage.



• Sufficient maxillary bone - ≥10mm length- Type 1, 2, or 3

• Favorable AP spread• Relative parallelism required

Study Criteria

Fulcrums

Occlusal View

T = Tension C = Compression

XX

Occlusal View

Fulcrums

C C

T T

T = Tension C = Compression

Occlusal View

C C

T T

XX

Fulcrums

Minimum AP Spread

Occlusal View

Sadowsky, S / Caputo, A.


Effect of Anchorage Systems and Extension Base Contact on Load

Transfer With Mandibular Implant-Retained Overdentures

Without Intimate extension base contact with the posterior edentulous ridge, the cantilevered anchorage systems generated the highest stresses, under load, to the ipsilateral terminal implant and the solitary anchor design transferred the least.

Without intimate extension base contact with the posterior edentulous ridge, the cantilevered anchorage systems

generated the highest stresses, under load, to the ipsilateral terminal implant.

With simulated intimate extension base contact, all anchorage systems transferred low stress to the distal

implant region.

Less Vertical Displacement

Greater Vertical

Displacement

Given Horizontal Flexure

Long Radius Sweep

Short Radius Sweep

Rotational Axis

Lateral Medial

Scar Band

Peripheral Consideration in Improving Obturator

Retention

Brown, KE J Prosthet Dent 20:176-81, 1968

Implant Supported Designs

Mandible vs. Maxilla

The Edentulous Mandible


Ambard, A et al.

J Am Dent Assoc 2002; 133:1237-1242

Cleansability of and Patient’s Satisfaction with Implant-Retained Overdentures: A Retrospective Comparison of

Two Attachment Methods

Patient’s satisfaction for a four implant-retained overdenture with non-splinted studs were equally similar to

those supported by four implants and a Hader bar.

Non-Splinted Splinted

Implant AssistedImplant Assisted

The Edentulous Maxilla


Overdentures• 15 – 17 mm

Hybrid Dentures• 13 – 15 mm

Ceramo-Metal• 9 – 13 mm

Vertical Space Requirements

# 27 # 22

Implant Spacing

1. Arch Size

2. Anatomy

3. Primary Bar Design

4. Attachment Positions and Types

Implant Spacing

1. Arch Size

2. Anatomy

3. Primary Bar Design

4. Attachment Positions and Types

7-8 mm

7-8 mm 7-8 m

m

Implant Spacing

Advanced Technologies

CAD/CAMPrecision Milled Bars

Computer Milling

Animation Scheme:Title descends in automatically. Every bullet enters on click. Reference at bottom descends automatically after last bullet.

Örttorp A, et al.

Int J Prosthodont 2003;16:194-200

Comparisons of Precision of Fit Between Cast and CNC-Milled Titanium Implant Frameworks For The Edentulous

Mandible

Purpose: The purpose of this study was to investigate and compare the precision of fabrication in repeatedly produced computer numeric controlled (CNC)–milled frameworks with conventional castings, and to analyze the distortion from application of different veneering materials. Materials and Methods: Twenty identical titanium frameworks were fabricated by means of a CNC milling technique for the same master model. Five conventional frameworks were cast as a control group to the same model. The frames were measured with regard to fit in a coordinate measuring machine linked to a computer. Measurements were made during different stages of handling of the titanium framework, and after veneering materials had been applied. Results: The CNC frameworks showed a statistically better fit and precision of fabrication compared to conventional castings ( P< .05). The application of veneering material did not statistically affect the fit of the titanium frameworks ( P> .05). Conclusion: It is possible to fabricate implant-supported frameworks by means of the present CNC technique with a very high precision and repeatability. Int J Prosthodont 2003;16:194–200.

Purpose:To investigate and compare the precision of fabrication of computer numeric controlled (CNC)–milled frameworks with conventional castings, and to analyze the distortion

from application of different veneering materials.


20 identical frameworks made by computer milling 5 conventional frameworks as control Computer milled frameworks showed better fit and

precision The application of veneering material did not

statistically affect the fit of the titanium frameworks


Conclusion:It is possible to fabricate implant-supported

frameworks by means of the present CNC technique with a very high precision and repeatability.


Types of CAD/CAM Bars

Text

ANIMATION SCHEME:None.


CT Guidance

Peker, I et al.

Int J Oral Maxillofac Implants 2008; 23:463-470

Fortin,T et al.

Clin Oral Impl Res 2002; 13(6):651-656

Sarment, D et al.




1. Measurements obtained from CT images were more consistent with direct measurements than the measurements obtained from panoramic radiographic images or conventional tomographic images.

2. Preoperative planning with CBCT can provide an extremely accurate method of transferring data to the patient and will help decrease anatomical injury.

3. Implant placement was improved with the use of stereolithographic implant guides.



1. Soft Tissue• Radiographic Guide or Dual Scan Technique

2. Bone•CBCT

3. Teeth•Cast for Scanning

Stereolithographic Implant Placement Guides

Support:


Immediate Occlusal Loading

Int J Oral Maxillofac Implants

2009; 24(suppl)

Consensus Statements and Recommended Clinical Procedures Regarding

Loading Protocols

We know that the literature supports immediate loading of microroughened implants with fixed prostheses in the edentulous maxilla.

Treatment is complex and is reserved for clinicians with appropriate education, experience, and skill.

One Prospective study of immed loading of implant supported max ODʼs Cannizzaro (2007) 12 patients .....48 implants............... ISR of 95.6%....... pros survival rate 100% .......1 year f/u period

What about the “All-on-Four” method for fixed restorations in the edentulous patient?

Silva, G et al.

Int J Oral Maxillofac Implants

2010; 25:239-246

Stress Patterns On Implants In Prostheses Supported By Four Or Six Implants: A Three-Dimensional Finite Element

Analysis

We know that the literature supports immediate loading of microroughened implants with fixed prostheses in the edentulous maxilla.

This study compared the biomechanical behavior of the “All-on-Four” system with that of a six-implant-

supported prosthesis in the maxilla.

The von Mises stresses induced on the implants under different loading situations were localized and

quantified.

• 3-D models were developed(4 implants and 6 implants)

• Models subjected to 4 different loading simulations- Loading 1: Full mouth biting (200N molars, 150N

2nd and 1st premolars,100N distal of canines) - Loading 2: Canine disclusion (50N)- Loading 3: Load on a cantilever (200N)- Loading 4: Load in absence of a cantilever

(200N)

Results

Maximum S Stress (MPa)

Loading Location of Peak Stress “All-on-Four” Model Six-Implant Model % Difference Between Values

1 MP area of tilted implant neck 139.4 125.8 -11

2 MB area of tilted implant neck 16.6 12.8 -29

3 MP area of tilted implant neck 104.4 97.4 -7

4 Mesial area of tilted implant neck 54.4 46.4 -17

Mean 78.7 70.6 -11

The von Mises stress values were 7% to 29% higher for the “All-on-Four” model (depending upon the simulation).

Are endosseous implants 100% successful?

When an implant fails are you ok with an “All-on-Three” fixed design?

Rodriguez, A et al.

Ann Periodontol 2000; 5:101-108

Survival of Various Implant-Supported Prosthesis Designs Following 36 Months of Clinical Function

5 Research Sratums -- Maxillary (completely edentulous) was one of the stratums

Background: The use of endosseous dental implants to replace natural teeth lost to trauma, dental caries, or periodontal disease has become a predictable form of prosthetic treatment since gaining popularity in the early 1980s. While numerous clinical studies have focused on the survival of implants, few address the survival of different prosthesis designs.Methods: Beginning in 1991, 882 prostheses supported by more than 2,900 implants (687 patients) were placed by the Department of Veterans Affairs Dental Implant Clinical Research Group (DICRG). These prostheses were divided into five research strata based on arch location. The recommended design for each stratum was: bar-supported overdenture (maxillary completely edentulous); screw-retained hybrid denture (mandibular completely edentulous); screw-retained fixed partial denture (mandibular and maxillary posterior partially edentulous); and cemented single crown (maxillary anterior single tooth). Alternative overdenture designs were utilized in the edentulous arches when the recommended prosthesis could not be fabricated. Prosthesis success rates for the research strata were calculated for an observation time of up to 36 months following prosthesis placement.Results: Success rates for the maxillary edentulous stratum ranged from 94.6% for the bar-retained overdenture supported by five to six fixtures to 81.8% for the cap-retained overdenture. The mandibular edentulous strata produced success rates of 98.1% for the fixed hybrid prosthesis to 91.7% for the cap-retained prosthesis. Success rates for maxillary and mandibular posterior fixed partial dentures were 94.3% and 92.6%, respectively, while the maxillary anterior single-tooth prosthesis yielded a success rate of 98.1% for the 36-month observation period.Conclusions: The recommended prosthesis designs investigated in this study proved to be reliable, with encouraging success rates for an observation period of 36 months following placement. Ann Periodontol 2000;5:101-108.

• 5 Research Stratums -- Maxillary (Completely Edentulous) 1 of 5

• Recommended Design For Maxilla- Bar-Supported Overdenture

• Alternative Overdenture Designs Were Utilized In The Edentulous Arches When The Recommended Prosthesis Could Not Be Fabricated

• Prosthesis success rates for the research strata were calculated for an observation time of up to 36 months following prosthesis placement



0

25

50

75

100

Bar-Supported OD Bar-Retained OD Cap-retained OD

81.886.794.6

Cumulative Survival at 36 Months

The bar-supported prosthesis design, supported by 5-6 implants



Palmqvist, S / Sondell, K / Swartz, B

Int J Oral Maxillofac Implants 1994; 9:184-190

Implant-Supported Maxillary Overdentures: Outcome in Planned and Emergency Cases


At the Postgraduate Dental Education Center, Örebro Sweden, maxillary implant-supported overdentures have mainly been used in either planned cases (where implants sufficient for a fixed prosthesis could not be placed) or emergency cases (originally planned for a fixed restoration but where implants lost during the healing period made such treatment impossible). Twenty-five cases were studied retrospectively. In the planned group, only two of 19 patients had lost an implant during the follow-up period with overdentures; in the emergency group, four subjects of six lost implant(s) during the same period. The total loss of implants during healing and overdenture function was 7% in the planned group and 72% in the emergency group. The curves for survival of overdentures without loss of supporting implants were significantly different (P = .00) for the planned group and the emergency group. (INT J ORAL MAXILLOFAC IMPLANTS 1994;9:184-190)

Maxillary overdenture success is higher when it is the planned restoration, rather than an alternative treatment

following unexpected fixture failure.


At the Postgraduate Dental Education Center, Örebro Sweden, maxillary implant-supported overdentures have mainly been used in either planned cases (where implants sufficient for a fixed prosthesis could not be placed) or emergency cases (originally planned for a fixed restoration but where implants lost during the healing period made such treatment impossible). Twenty-five cases were studied retrospectively. In the planned group, only two of 19 patients had lost an implant during the follow-up period with overdentures; in the emergency group, four subjects of six lost implant(s) during the same period. The total loss of implants during healing and overdenture function was 7% in the planned group and 72% in the emergency group. The curves for survival of overdentures without loss of supporting implants were significantly different (P = .00) for the planned group and the emergency group. (INT J ORAL MAXILLOFAC IMPLANTS 1994;9:184-190)

Steven J. LoCascio, D.D.S.306 Prosperity Drive Suite 201

Knoxville, Tennessee [email protected]

Thank You!

www.easCnprosthodonFcs.com

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