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.

A cost minimization analysis of implant treatment in mandibular edentulous patients.

PURPOSE: This study aimed to determine if implant-supported overdentures are a long-term economically efficacious therapy for edentulous patients when compared to fixed osseointegrated prostheses. MATERIALS AND METHODS: Clinical records of 25 patients from two long-term studies (fixed and overdenture) were included in this analysis. A cost minimization analysis from the patient perspective was employed. Direct clinical and time costs incurred over the 9-year period were deflated to 1995 Canadian dollars using the Consumer Price Index. National salary rates by occupation and gender were used to value patients' time, and a sensitivity analysis was carried out to assess the robustness of the results when an equal mean salary rate across treatment groups was assumed. RESULTS: The mean total, clinical, and time costs were significantly higher (Ps .05) for the fixed restoration group (dollars CAD10,748, dollars CAD10,094, and dollars CAD654, respectively) when compared to the overdenture group (dollars CAD3,665, dollars CAD3,343, and dollars CAD322, respectively). The initial, maintenance, and clinical visit costs were also significantly higher (P < or = .05) in the fixed restoration group (dollars CAD7,567, dollars CAD2,527, dollars CAD542, respectively) than in the overdenture group (dollars CAD2,505, dollars CAD830, dollars CAD292, respectively). The sensitivity analysis demonstrated that the time cost for the fixed prosthodontic group (dollars CAD488 vs dollars CAD322) was still significantly higher (P = .002), even after an equal mean salary rate was assumed. CONCLUSION: Overdenture therapy for edentulous patients is a more cost-effective treatment compared to fixed prosthodontic treatment.

Frequency and costs of technical failures of clasp- and double crown-retained removable partial dentures.

OBJECTIVES: The aim of this study was to evaluate the frequency of technical failure rates and the maintenance costs of clasp- or double crown-retained removable partial dentures (RPDs) (parallel-sided and conical double crowns). MATERIAL AND METHODS: According to three different retainer systems used between January 1992 to December 1998, three subgroups were randomly assigned from a group of 181 patients consisting of forty cases each. The average observation time was 4.2+/-1.7 years, with a minimum of 1.0 years and a maximum of 6.9 years. Technical complications such as fractures of the artificial teeth, loss of cementation, loss of facings as well as fractures of the metal framework and the soldering were recorded due to the medical reports. RESULTS: Twenty percent of all clasp-retained dentures showed technical complications during the observation period, whereas 50% of conical crown-retained (CC) and 32.5% of the parallel-sided retained dentures (PS) required repair. Most often reported was loss of cementation for double crowns (n=13, 32.5% PS; n=8, 20% CC) and fractures of the clasps (n=5). Although clasp-retained dentures had a markedly lower frequency of failures (n=8) than double crown systems (n=31), the calculated repair costs per event during the observation time were more than twice as high for clasp-retained dentures (172.5 Euro) than for double crown systems (8-78 Euro). The hypothesis that the maintenance costs of the more sophisticated double crown system are higher must be rejected.

One-year prosthetic outcomes with implant overdentures: a randomized clinical trial.

PURPOSE: This randomized clinical trial examined implant overdenture (IOD) fabrication and maintenance time and costs, adjustment and repair incidence, and patient satisfaction after 1 year. MATERIALS AND METHODS: Sixty-four patients received 2 mandibular implants and an IOD with either a bar with 2 clips or 2 ball attachments for denture retention. RESULTS: Fabrication time, number of appointments, and chair time for adjustments were similar for the 2 denture designs. The most common adjustments for both types were to the IOD contours. Ball-attachment dentures required about 8 times longer for repairs than bar-clip prostheses. Approximately 84% of patients with ball-attachment dentures needed at least 1 repair, versus 20% of those with a bar-clip mechanism. The most common repairs were replacement of the cap spring or cap for the ball-attachment IOD and replacement of a lost or loose clip for bar-clip dentures. DISCUSSION: Patients were equally and highly satisfied with the improvements in function, comfort, and appearance with both types of IOD compared to their original conventional dentures. CONCLUSIONS: Given equivalent levels of patient satisfaction with either method of retention and a much higher repair rate for the ball attachment, it is suggested that a bar-clip design be used rather than the particular ball attachment utilized in this study.

[Toward a more resistant resin, more economical and better suited to conditions in developing countries]. / Pour une resine plus resistante, plus economique et adaptee aux contextes des pays du sud.

The breakage of prosthesis constructed in polymethacrylate resin is a reality in daily practice. Several solutions have been proposed to overcome this problem. Thus, the reinforcement of resin with carbon fibre improved greatly the mechanical properties, notably the fatigue strength. The technique of elaboration of such prosthesis proposed in this study has little impact on aesthetic as well as on the final cost. This proposition could be a relevant solution for third world countries opposite to economical and technological problems generated by cast metallic framework.

Denturists: do they really provide more affordable care in Ontario?

The 1996 Denturist Association of Ontario fee guide and the Ontario Dental Association Fee Guide for General Practitioners were examined to identify variations in the fees charged for a range of removable prosthodontic services. Fee guides were selected for this analysis as third-party insurers and government dental plans frequently use them to establish fee schedules and levels of reimbursement. However, it is recognized that dentists set their own fees, which may be higher or lower than the fees suggested in the guide. Although the descriptions of the specific services listed in the guides were similar in many cases, no attempt was made to examine variations in the quality of care provided by dentists and denturists, or the approach to treatment offered by their respective professions. The analysis revealed that a number of procedure fees were, on average, 15 per cent higher in the Ontario Dental Association (ODA) fee guide compared to the denturists' fee guide. However, a wide range of prosthetic services, including partial dentures, were less expensive in the ODA fee guide. Based on this analysis, there appears to be no substantial cost differential between the services provided by dentists and denturists six years after the proclamation of the new Regulated Health Professions Act in Ontario, as the denturists have claimed. The denturist association's further claims of greater choice and improved access may also be questionable, and should be reexamined in light of these findings.

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.