Longitudinal Assessment of Denture Maintenance Needs in an Overdenture Population.

PURPOSE: To evaluate the longitudinal denture maintenance needs of a tooth-supported overdenture population. MATERIALS AND METHODS: This prospective cohort study was composed of patients who had received tooth-supported overdentures from 1974 to 1994 in the Department of Prosthodontics, University of Iowa. There were 272 persons with 662 abutments who fulfilled the inclusion criteria. To simplify analysis and reduce the number of confounding variables, only those participants wearing complete maxillary dentures and opposing complete mandibular overdentures supported by teeth #22 and #27 were included in this analysis. The denture maintenance needs of these participants were identified and related to age, gender, length of time wearing overdentures, number of medications, and denture-wearing habits. Descriptive statistics and bivariate analyses were used for the statistical analysis (α = 0.05). RESULTS: Of the 91 participants (mean age = 59.5 ± 10.1 years; 63.7% male) who fulfilled the inclusion criteria at baseline, 48.4% took 1 to 3 medications daily, and 84.6% wore their dentures day and night. The percentages of participants who needed one or more of the following denture treatments were: 91.2% denture base adjustments, 76.9% laboratory processed relines, 61.5% denture remakes, 33% laboratory remount and occlusal adjustment, 22% repaired bases, and 19.8% needed denture teeth replaced. Bivariate analyses indicated that participants who were 65 years and older needed more denture adjustments than patients younger than 65 years (p = 0.0343). Participants who had worn overdentures for more than 5 years were more likely to require denture remakes (p = 0.0304). Participants who wore their dentures only during the day were less likely to require repairs (p = 0.0403). Participants who did not take any medications were significantly less likely to require denture base repairs (p = 0.0258). For the 35 participants who returned for recalls at all 4 time points, males were more likely to need denture teeth repaired or replaced (p = 0.0335) and those aged 50 to 64 were more likely to need 2 or more adjustments (p = 0.0311). No overdenture abutments were lost by the participants in this study. CONCLUSIONS: According to the results of this study, age, medication usage, denture-wearing habits, and age of the overdentures were significant factors associated with denture maintenance needs. Persons wearing overdentures need regular recalls, because they have continuing maintenance needs.

Clinical performance of CAD-CAM-fabricated complete dentures: A cross-sectional study.

STATEMENT OF PROBLEM: Computer-aided design and computer-aided manufacture (CAD-CAM)-fabricated complete dentures (CD) seek to address the disadvantages associated with conventional CD fabrication. However, few if any randomized clinical trials, cross-sectional, and/or retrospective analyses are available for the clinical performance of CAD-CAM-fabricated CDs. PURPOSE: The purpose of this retrospective study was to evaluate clinician experience with digital CD fabrication attempted in a 2-visit protocol. The actual number of appointments required for insertion and the number of postinsertion adjustment visits, and whether the incidence of treatment complications was related to operator experience were recorded and evaluated. MATERIAL AND METHODS: Patients who had received CAD-CAM-fabricated CDs were identified from a retrospective chart review. The number of appointments needed to insert digital CDs in attempting the 2-visit fabrication protocol marketed by the company, the number of postinsertion adjustments, and the reported complications were counted. There was no control group for comparative purposes used in this study. Whether the experience level of the operator influenced the frequency of a complication, the number of appointments needed to insert the definitive prostheses, and the number of postinsertion visits was determined by using an analysis of variance assessed at the 95% confidence level (α=.05). The frequency of a complication at each of the levels of operator experience was analyzed using the Exact Mantel-Haenszel chi-square test. RESULTS: Of the 48 rehabilitated participants, 24 participants were treated at the predoctoral level and 24 were treated at the graduate prosthodontics resident level. A total of 31 participants satisfied the true 2-visit fabrication protocol, and the remaining 17 participants required additional clinical visits because of complications on the day of insertion. The CD prostheses of 5 participants from the sample population required remaking using the conventional method. The mean number of postinsertion adjustment visits was 2.08. Of the 90 arches completed, 22 prostheses could not be inserted at the second appointment. CONCLUSIONS: The mean number of appointments needed to insert the prostheses in both groups was 2.39 visits--not 2 as claimed by the company. The most common types of complications observed were lack of denture retention, inaccurate occlusal vertical dimension, and incorrect centric relation.

The Retread: A Definition and Retrospective Analysis of 205 Implant-Supported Fixed Prostheses.

PURPOSE: Acrylic resin teeth on fixed implant prostheses are subject to time-dependent wear. The purpose of this retrospective analysis is to evaluate and describe the management of such wear in the context of selected variables--patient gender and age, dental arch location, and opposing dentition. The clinical and dental laboratory process to replace the worn teeth is defined as a retread. MATERIALS AND METHODS: A retrospective database review from a single private prosthodontic practice was carried out on all patients who had undergone a retread procedure. The patient pool included 205 arches in 194 patients (70 in men, 135 in women) with a mean age of 57.4 years (range: 19.9 to 80.5 years). The retread procedure is described. RESULTS: The mean time between final prosthesis delivery and retread was 7.8 years (range: 1.1 to 22.9 years). Statistical analysis was significant according to dental arch and opposing dentition. A statistical difference was also noted in patients undergoing multiple retread procedures, with a reduction in time between the subsequent procedures. CONCLUSION: Acrylic resin components of implant-supported hybrid prostheses wear over time and are influenced by a combination of the nature of the opposing dentition and patient habits. The dental laboratory process to retread the implant-supported framework is important for long-term patient care and maintenance of an appropriate vertical dimension of occlusion.

Three-Year Analysis of Fixed and Removable Telescopic Attachment-Retained Implant-Supported Dental Prostheses: Survival and Need for Maintenance.

PURPOSE: The purpose of this retrospective clinical study was to evaluate the clinical outcomes of fixed implant-supported dental prostheses (FISDPs) and removable ISDPs (RISDPs) retained by telescopic attachments, the factors influencing survival, and the type and number of maintenance treatments required during the observation period. MATERIALS AND METHODS: This retrospective clinical study is based on patients who were provided with ISDPs between 2004 and 2010. Patient sex, type of prosthesis, location, opposing dentition, and the effect of continuous follow-up on the probability of a favorable outcome, as well as the number of maintenance treatments, were analyzed. A statistical analysis was performed using the Kaplan-Meier method. RESULTS: A sample of 233 patients with 157 FISDPs and 76 RISDPs supported by a total of 567 implants was randomized and included in the analysis. The mean observation period was 15.9 ± 15.4 months (maximum, 66.0 months). During the observation period, 3.9% of prostheses (7/157 FISDPs and 2/76 RISDPs) ceased to function and 2.3% of implants (13 implants) were lost. The mean survival time was 59.7 ± 2.3 months, with a survival probability of 90.2% after 3 years. Prostheses in the mandible showed significantly higher survival rates than those in the maxilla. Maintenance treatments had to be performed at an earlier stage for patients with RISDPs than for patients with FISDPs. In patients with a conventional removable prosthesis in the opposing arch, the time until maintenance was needed was significantly shorter. CONCLUSION: Within the limitations of a retrospective study, it can be concluded that the FISDPs and RISDPs show equally good survival rates after 3 years in function. RISDPs showed a greater and earlier need for maintenance treatments during the first years in function.

Treatment outcomes with removable partial dentures: a retrospective analysis.

PURPOSE: This retrospective clinical study aimed to evaluate the long-term outcomes of clasp-retained, metal-framework removable partial dentures (RPDs) and their clasped teeth, the influencing factors on survival, and the type and number of repairs needed during the observation period. MATERIALS AND METHODS: The study is based on a convenience sample of 52 patients who received 65 RPDs with a total of 207 clasped teeth. The mean observation period was 3.11 ± 0.29 years (maximum: 10 years). Patient gender, prosthesis location (maxilla/mandible), number and distribution (Kennedy class) of abutment teeth, and impact of a continuous follow-up program on a favorable outcome probability were analyzed. Statistical analysis was performed using the Kaplan-Meier method (P < .05) in combination with Cox regression analysis. RESULTS: During the observation period, 9.2% of the RPDs ceased to function and 5.8% of the abutment teeth were extracted. Mean RPD survival time was 8.07 ± 0.66 years, with a positive outcome probability of 90% after 5 years. Prosthesis location was the only parameter that significantly (P < .05) impacted this probability. CONCLUSION: Overall, the high survival probability and low extraction rate of the abutment teeth reported in this study indicate that RPDs designed according to hygienic pronciples are clinically successful.

Immediate loading of unsplinted implants in the anterior mandible for overdentures: 3-year results.

PURPOSE: This 3-year study evaluated the implant survival rate, peri-implant tissue response, prosthetic maintenance, and prosthetic complications in a series of patients who received two immediately loaded unsplinted threaded implants to retain a mandibular overdenture. MATERIALS AND METHODS: Eight completely edentulous patients were evaluated clinically and radiographically immediately after implant placement, at 3 months, and at 1, 2, and 3 years after implant placement. Data were analyzed using repeated-measures one-way analysis of variance and the Wilcoxon signed rank test at a significance level of α = .05. RESULTS: At 3 years, all implants remained osseointegrated (16/16), with an overall mean marginal bone change of -0.58 ± 0.39 mm and a mean Periotest value of -7.19 ± 0.54. The modified Plaque Index scores showed marked improvement in oral hygiene during the first year, but some relapse was observed thereafter. Prosthetic maintenance and complications included replacement of the attachment inserts, abutment loosening, dislodgement of the attachment housing, overdenture reline, denture tooth fracture, and overdenture base fracture. CONCLUSIONS: This 3-year study suggests that, despite less than ideal oral hygiene and a high incidence of complete/partial fracture of overdentures, favorable implant survival rate and peri-implant tissue responses can be achieved in mandibular overdentures retained with two immediately loaded unsplinted threaded implants.

[Dental treatment strategies for elderly patients]. / Strategia de tratament stomatologic la pacientul vârstnic.

UNLABELLED: The elderly are influenced from a various and complex combination of factors, such us individual genetic predispositions, lifestyle, society and environment, the sum of all the individual life experiences concerning the dental care, the caries, the periodontal and iatrogenic diseases. AIM: This paper evaluates the dental treatment in the elderly. MATERIAL AND METHODS: The study was performed on 112 patients, aged over 65, at the Clinical Department of Dental Semiology und Geriatric Dentistry, Iasi, Romania. RESULTS: The treatment interventions were dental hygiene procedures (in 97 patients), restaurations (in 29 patients), removable partial and total denture preocedures (in 50 patients), fixed prosthetic procedures (in 18 patients), rebasing of dentures (in 25 patients) and teeth extractions (in 26 patients). There were 36 endodontic emergencies and 15 periodontal emergencies and 8 emergencies that resulted from other causes. CONCLUSIONS: The periodical dental examinations and the proper daily oral hygiene routine are still important in the old age and they should not be neglected, because the prosthetical components request also treatment interventions.

Maintenance of implant-supported maxillary prostheses: a 2-year controlled clinical trial.

PURPOSE: To analyze maintenance service of fixed maxillary prostheses and overdentures based on conventional gold bars or titanium bars and frameworks fabricated with computer-aided design/computer-assisted manufacture (CAD/CAM) technology. MATERIALS AND METHODS: Forty-one patients participated; 16 received an implant overdenture with a gold bar (gold OD), 12 received a CAD/CAM-fabricated implant OD with a titanium bar (Ti OD), and 13 received a CAD/CAM implant-supported fixed prosthesis (IFP). The bars and frameworks were screw-retained at the implant level. Maintenance service performed during the first 2 years was recorded and compared between the three groups. After this 2-year period, the Oral Health Impact Profile (OHIP) was administered. RESULTS: For ODs (gold, Ti) most service consisted of activation of the matrices. Fractures of matrices and bar extensions occurred only in the gold OD group, and 65% of these patients exhibited hyperplasia of the peri-implant mucosa. The maintenance rates were 1.24 (gold OD), 1.36 (Ti OD), and 0.98 (IFP). These differences were not statistically significant. Retightening of occlusal screws was not necessary in any group. The probability that a complication occurred in the first year was high (60% to 70%) and statistically not different between the three groups. The probability that a second complication occurred was significantly lower for the IFP group versus the gold OD group. The mean OHIP values were 1.7 (IFP), 6.7 (gold OD), and 7.3 (Ti OD); ratings in the IFP group were significantly better. CONCLUSIONS: Maintenance service was typical for implant prostheses in the edentulous maxilla. Direct screw retention at the implant level without abutments had a favorable effect in all groups. A trend toward a reduction in problems was observed with the CAD/CAM superstructures. The OHIP confirmed high satisfaction, but quality of life appeared to be slightly higher with fixed prostheses.

Long-term prosthetic aftercare of direct vs. indirect attachment incorporation techniques to mandibular implant-supported overdenture.

OBJECTIVE: The aim of this long-term study was to compare the need for prosthetic aftercare of direct vs. indirect attachment incorporation techniques to mandibular implant-supported overdenture. MATERIALS AND METHODS: Forty-five consecutive patients were included (130 implants were placed). Treatment was randomly allocated, resulting in 22 patients (group A) to be treated with direct ball attachment incorporation and 23 patients (group B) to be treated with indirect ball attachment incorporation. All patients were treated by experienced oral-maxillofacial surgeons/periodontists and experienced prosthodontists/residents. From the first day that the patients visited the clinic up to 20 years after the first treatment session, all surgical or prosthetic therapeutic interventions were recorded. The recorded data for the present study included the number of aftercare visits and dental treatment received (pressure sores relieve, liner changes due to loss of retention and attachment replacement due to wear). RESULTS: The mean follow-up was 93±57 months. No implants were lost. Statistical analysis revealed a statistically significantly (P<0.001) greater need for prosthetic interventions in group B vs. group A. The mean number of visits dedicated to - pressure sores relieve (7.04±1.4 vs. 3.63±0.84); liner exchange due to loss of retention (3.6±1.3 vs. 1.09±1.06) was significantly higher in group B. Attachment replacement due to wear occurred only in group B (11/23 - 47.8%). CONCLUSION: The direct technique for attachment incorporation in mandibular implant-supported overdentures using ball attachments is superior to the indirect technique from the aftercare perspective during a long-term evaluation period.

Mandibular implant overdentures followed for over 10 years: patient compliance and prosthetic maintenance.

PURPOSE: The mandibular implant overdenture is a popular treatment modality and is well documented in the literature. Follow-up studies with a long observation period are difficult to perform due to the increasing age of patients. The present data summarize a long-term clinical observation of patients with implant overdentures. MATERIALS AND METHODS: Between 1984 and 1997, edentulous patients were consecutively admitted for treatment with an implant overdenture. The dentures were connected to the implants by means of bars or ball anchors. Regular maintenance was provided with at least one or two scheduled visits per year. Recall attendance and reasons for dropout were analyzed based on the specific history of the patient. Denture maintenance service, relining, repair, and fabrication of new dentures were identified, and complications with the retention devices specified separately. RESULTS: In the time period from 1984 to 2008, 147 patients with a total of 314 implants had completed a follow-up period of >10 years. One hundred one patients were still available in 2008, while 46 patients were not reexamined for various reasons. Compliance was high, with a regular recall attendance of >90%. More than 80% of dentures remained in continuous service. Although major prosthetic maintenance was rather low in relation to the long observation period, visits to a dental hygienist and dentist resulted in an annual visit rate of 1.5 and 2.4, respectively. If new dentures became necessary, these were made in student courses, which increased the treatment time and number of appointments needed. Complications with the retention devices consisted mostly of the mounting of new female retainers, the repair of bars, and the changing of ball anchors. The average number of events and the rate of prosthetic service with ball anchors were significantly higher than those with bars. Twenty-two patients changed from ball anchors to bars; 9 patients switched from a clip bar to a rigid U-shaped bar. CONCLUSIONS: This long-term follow-up study demonstrates that implant overdentures are a favorable solution for edentulous patients with regular maintenance. In spite of specific circumstances in an aging population, it is possible to provide long-term care, resulting in a good prognosis and low risk for this treatment modality. For various reasons the dropout rate can be considerable in elderly patients and prosthetic service must be provided regularly.

A clinical trial of patient satisfaction and prosthodontic needs with ball and bar attachments for implant-retained complete overdentures: three-year results.

STATEMENT OF PROBLEM: Few prospective trials of implant-retained mandibular dentures have evaluated the increase and duration of patient satisfaction, costs of denture maintenance in relation to different methods of attaching overdentures to implants, or the use of a reinforced framework. PURPOSE: This report evaluates subjects' satisfaction and prosthodontic maintenance during a 3-year randomized clinical trial of implant-retained mandibular complete dentures, whether reinforced or not with a cast framework, and attached by bar-clip or 2.25-mm ball-spring matrices to endosteal dental implants. MATERIALS AND METHODS: One hundred edentulous subjects, each having at least 1 year's experience with conventional complete dentures, were selected from respondents to a university dental clinic's request for volunteers. Candidates were examined to verify adequate mandibular bone and medical suitability for implants. Subjects then received 2 implants in the anterior mandible before being stratified by mandibular bone height and gender and assigned randomly to 1 of 4 treatment groups. Every subject received a new maxillary complete denture in addition to an implant-supported mandibular complete denture, with or without a reinforcing framework, connected to implants by either a bar-clip or a ball-spring patrix and matrix. The dentures were adjusted and repaired as needed. Subjects indicated on a visual analogue scale (VAS) satisfaction with conventional dentures prior to the study and then with new dentures at 1 month, 1 year, and 2 years. The results reported here are from the first 68 subjects observed for 3 years after receiving new dentures (19 subjects received new dentures less than 3 years before this analysis, and another 13 subjects were lost to follow-up). VAS scores are presented in simple tables and graphs, and results for different groups were compared using 2-sided nonparametric rank tests and repeated measures ANOVA. With respect to costs and maintenance, t tests were used to compare group means. Sample size and other design considerations used a .05 significance level. RESULTS: After receiving new dentures with mandibular implant supports, improved satisfaction "within subject" was prompt, durable, substantial, and statistically significant, regardless of the attachment mechanism, and with or without a reinforcing framework. In contrast, there were no notable satisfaction differences between the 2 attachment mechanisms, or with the presence or absence of a reinforcing framework, either at specific intervals after receiving the new dentures, or in repeated measures ANOVA. For both attachment groups, most denture adjustments occurred during the first year. This accounted for 81% of total adjustments during 3 years, when the 34 subjects in the ball-spring group and the 34 in the bar-clip group were combined. The mean numbers of adjustments per subject and associated clinical times did not differ significantly between the 2 groups. Conversely, denture repairs declined more slowly than adjustments. Almost all repairs (90%) occurred in the ball-spring group to correct problems with the attachments, 39% in the first year, and tapering off only slightly in the following 2 years. Over 3 years of follow-up, mean numbers of repairs per subject differed significantly between groups: 6.7 repairs per person in the ball-spring group, compared to 0.8 in the bar-clip group ( P<.001), and mean time per appointment was greater for repairs in the ball-spring group: 18.9 minutes compared to 16.9 ( P<.01). The cast framework had no influence on the satisfaction expressed or on adjustments and repairs. CONCLUSION: Subjects were very satisfied with the new dentures, although the ball-spring attachment tested in this trial required substantially more repairs.

Denture satisfaction and clinical performance in a paediatric population.

OBJECTIVES: The objectives of this study were to investigate the clinical performance of partial upper dentures in children and to assess reported denture satisfaction in this young population. DESIGN: This was a retrospective study using patients' dental records in conjunction with a postal questionnaire. SETTING: The Paediatric Dentistry Clinic, School of Clinical Dentistry, Sheffield. SAMPLE AND METHODS: Fifty-eight children (aged 7-17 years) who had been provided with a partial upper denture to replace one or more missing permanent incisors were included in the study. The patients' dental records were examined for the following details: tooth type missing, presence of retained incisor roots, aetiology of tooth absence, age at which the denture was first provided, total time period dentures had been worn, and frequency and type of any denture repairs or replacements. Next a short questionnaire was sent to each child, which sought an evaluation of several parameters of denture satisfaction including: overall attitude towards wearing a denture, denture appearance, ease of eating, comfort and perceived degree of teasing from peers. Visual analogue scales (VAS) were employed to provide a graded response. RESULTS: 70.7% of subjects had a single missing incisor and trauma was the most common cause of tooth loss (77.3%). The mean age at which patients started wearing a denture was 11.6 years and the mean length of time dentures had been worn, at the time of the investigation, was 2.1 years. A 'T-shaped' denture was most commonly employed (77.5% of dentures). Overall, 36.2% of subjects had required at least one denture repair, 28.2% presenting within a year of denture provision. One or more denture replacements had been received by 60.3% of the patients, and 43.6% had required this within a year. Component failure was highest for the denture tooth (40% of repairs) and a change in the patient's dentition necessitated a denture remake in 66% of cases. VAS scores for parameters of denture satisfaction indicated an overall positive evaluation of the dentures, with the most positive response relating to ease of eating. However, the reported degree of teasing was high and increased with time. The only significant difference for denture satisfaction according to gender was for mastication: girls reportedly found eating easier than did boys. CONCLUSION: Children are generally accepting of upper partial dentures, but their poor clinical performance is of concern and there is need for improvement.

[Dental treatment and oral health care on Tokashiki Island, Okinawa].

Okinawa Prefecture has been promoting dental treatment and oral health care in places where there are no dentists. The Ministry of Health and Welfare has been cooperating with eight dental colleges, including Tokyo Medical and Dental University, for promotion thereof since 1961. The 155th promotion was held on Tokashiki Island. The caries prevalence rate of the students on Tokashiki Island was relatively high compared with the average caries prevalence rate of the same age group throughout Japan, and most of the caries were thought to be due to too many soft drinks. Resin filling was the most popular treatment during this promotion. Severe periodontal disease was observed in middle-aged persons, but we could only perform initial periodontal treatment because of the limited treatment period. Complete or partial dentures were made or repaired for many elderly. The questionnaire study showed most of the denture wearers on Tokashiki Island were satisfied with their dentures, although many dentures did not fit, and the prescription was improved. The period of this promotion was too short to perform complete dental treatment and to prevent caries and periodontal disease, and primary prevention and higher dental hygiene education should be strengthened in no dentist areas like Tokashiki Island.

Repair of acrylic resin denture base reinforced with glass fiber.

STATEMENT OF PROBLEM: The ultimate goal of any denture repair is to restore the original strength of the denture and to avoid further fracture. PURPOSE: This study investigated the strength and deflection of repaired acrylic resin joints reinforced with various glass fiber concentrations. MATERIAL AND METHODS: Transverse strength, maximum deflection, and modulus of elasticity of glass fiber-reinforced polymethyl methacrylate acrylic resin were studied with a 3-point load test on 54 intact specimens. Six concentrations of type B glass fiber specimens were prepared (n = 9 per each fiber group). Fractured joint margins were rounded, a 2-mm gap was placed between them, and then they were repaired with autopolymerizing acrylic resin and retested. RESULTS: Transverse strength, maximum deflection, and the stiffness of all joints were significantly lower after the repair. Among the groups tested, the units treated with 1% glass fiber displayed the highest transverse strength before and after repair. Modulus of elasticity of the repaired 1% fiber concentration units was enhanced by approximately 25% over those repaired but untreated with glass fiber (0% fiber).

Removable prosthodontics: a survey of practices and attitudes among South Australian dentists.

All dentists registered in South Australia were surveyed in July 1993 in relation to removable prosthodontics. The replies indicated that removable prosthodontics constituted a significant part of most dental practices. Most dentists felt that removable prosthodontics should be an essential part of the undergraduate curriculum. They felt that more expertise is now required to manage the treatment of the ageing population with either their first or replacement removable prostheses. The majority of dentists felt that their own undergraduate training had equipped them well to manage removable prosthodontic treatment for their patients; however, many helpful suggestions were made on areas that they thought required more emphasis.

Denture fracture--a survey.

The fracture of dentures is an unresolved problem. Despite increasing costs incurred by the nation on the repair of these prostheses, very little has been documented on the type of fracture encountered. This survey was carried out to determine the prevalence of type of fracture by the distribution of questionnaires to three different laboratories. Results obtained showed that 33% of the repairs carried out were due to debonded/detached teeth. Twenty-nine per cent were repairs to midline fractures, more commonly seen in upper complete dentures. The remaining 38% were other types of fractures, the majority of which constituted repairs to upper partial dentures. The latter involved detachment of acrylic resin saddles from the metal in metal based dentures and the fractures of connectors in the all-acrylic resin partial dentures.

A retrospective study on the maintenance and repair of implant-supported prostheses.

This study reviewed the prosthodontic treatment and aftercare required by 29 patients with 32 implant-supported prostheses (12 fixed and 20 removable) placed on 107 implants. Patients were followed for 4 to 39 months. The majority of implant-supported prostheses (53%) were placed in the mandible. Visual analogue scales were used by the patients to rate their satisfaction with their prostheses and their chewing ability. Approximately one third of the patients studied required three or more relines of their existing dentures between first- and second-stage surgeries, while over half of the definitive implant-supported prostheses required a major adjustment or repair. Removable prostheses required 78% of the total repairs and accounted for 80% of those prostheses that needed repeated repairs. In general, patients were very satisfied with their implant-supported prostheses, but 17% complained of mild speech difficulties and 7% noted slight difficulty in cleaning their fixed prostheses. Overall, the short-term prosthetic management required for the implant-supported prostheses in this study was substantial, particularly with the removable prostheses, and this should be taken into account when evaluating prosthetic options.

Analysis of debond rates of resin-bonded prostheses.

Debonding rates of 164 resin-bonded prostheses (RBP) placed from 1974 to 1985 were examined at recall. The yearly debond rates were calculated, the cumulative probability of failure was determined for the debonded RBPs, and Weibull distribution parameters were determined. For perforated prostheses, there was a high initial debond rate, followed by slowly decreasing rates for about 5 years. Increasing rates after 5 years indicated the beginning of wear-out. The Weibull parameters for the wear-out period of the perforated prostheses were: characteristic life = 128 (SE = 2) months, modulus = 1.27 (0.06), and threshold parameter = 0. Data were available for etched frameworks for 6 years and showed decreasing debond rates during this time. The characteristic life of the etched bridges was 318 (84) months. The cumulative failure data were also modeled with a cubic polynomial distribution that resulted in a U-shaped hazard function.