Utilization of denture adhesives and the factors associated with its use: a cross-sectional survey.

BACKGROUND: An increase in the number of elderly edentulous patients likely leads to a greater demand for dentures and denture adhesives. As denture adhesives have both positive and negative features, dentists need to know the types of denture adhesive users to be able to provide instruction to denture wearers on how to use denture adhesives effectively. This study aims to examine the utilization of denture adhesives and associated factors. METHODS: Seven closed-ended questionnaires were developed for a web-based survey. After that, Fisher's exact tests were performed to determine the difference in the denture adhesive usage rate by gender, type of denture, last dental visit, and smoking status. A multivariate-adjusted logistic regression analysis was performed with denture adhesive use or non-use as the dependent variable and the other items as independent variables. Next, Fisher's exact tests and a multivariate-adjusted logistic regression analysis were performed with the type of denture adhesives as the dependent variable in the same way. Statistical analyses were performed for all denture wearers, complete denture wearers, and partial denture wearers. The level of statistical significance was set at p = 0.05. RESULTS: A total of 1470 denture wearers in Japan participated in this study. Of these, 318 used denture adhesives, while 212 (66.7%) used cream; 74 (23.3%) used home liner; 25 (7.9%) used powder; four (1.3%) used sheets; and three (0.9%) used several types. The Fisher's exact tests revealed that the ratios of using denture adhesives were significantly higher for complete denture wearers (p < 0.001), last dental visit over 1 year (p = 0.005), and smokers (p = 0.005). For partial denture wearers, the ratio was significantly higher in smokers (p = 0.262). The multivariate adjusted logistic regression revealed that denture adhesive use or non-use were significantly associated with the type of denture and smoking status in all denture wearers, and just smoking status in partial denture wearers. There were no significant results about the type of denture adhesive selection. CONCLUSIONS: From all denture wearers, complete denture wearers and smokers are more likely to use denture adhesives. In addition, smokers significantly use denture adhesives if they are partial denture wearers.

Factors associated with the non-wear of mandibular dentures in the Brazilian public primary health care.

This study investigated factors that affect the use of complete conventional mandibular dentures (CCMD) by patients of the Brazilian Public Health Service. For this, two hundred and thirty one subjects who received CCMD in the Primary Health Care of the Public Health Service in Belo Horizonte - Brazil were evaluated and divided in Group 1 - irregular/non-wear; Group 2 - regular wear. Multivariate logistic regression analysis was used to create predictive models for CCMD non-wear and included socio-demographic and biological variables, technical quality of CCMD, and user satisfaction. The prevalence of CCMD non-wear was 41.10%. The mean score of CCMD quality was 54.97 (0-100). Not wearing the CCMD was significantly associated with user satisfaction and technical quality (p < 0.05). The lack of retention of the CCMD was the most important factor in the evaluation of satisfaction and quality. The final predictive model (specificity = 92.65%; AROC = 0.8759) for not wearing the CCMD retained the variables CCMD stability (OR = 0.888; 95%CI = 0.827-0.954), freeway space (OR = 0.916; 95%CI = 0.860-0.976), satisfaction with speech (OR = 0.694; 95%CI = 0.612-0.786), and irregular CCMD edges (OR = 3.185; 95%CI = 1.478-6.864). Socio-demographic and biological variables were not associated with patients not wearing the CCMD, whereas technical quality and user satisfaction were strongly associated.

Factors associated with the non-wear of mandibular dentures in the Brazilian public primary health care

Abstract This study investigated factors that affect the use of complete conventional mandibular dentures (CCMD) by patients of the Brazilian Public Health Service. For this, two hundred and thirty one subjects who received CCMD in the Primary Health Care of the Public Health Service in Belo Horizonte - Brazil were evaluated and divided in Group 1 - irregular/non-wear; Group 2 - regular wear. Multivariate logistic regression analysis was used to create predictive models for CCMD non-wear and included socio-demographic and biological variables, technical quality of CCMD, and user satisfaction. The prevalence of CCMD non-wear was 41.10%. The mean score of CCMD quality was 54.97 (0-100). Not wearing the CCMD was significantly associated with user satisfaction and technical quality (p < 0.05). The lack of retention of the CCMD was the most important factor in the evaluation of satisfaction and quality. The final predictive model (specificity = 92.65%; AROC = 0.8759) for not wearing the CCMD retained the variables CCMD stability (OR = 0.888; 95%CI = 0.827-0.954), freeway space (OR = 0.916; 95%CI = 0.860-0.976), satisfaction with speech (OR = 0.694; 95%CI = 0.612-0.786), and irregular CCMD edges (OR = 3.185; 95%CI = 1.478-6.864). Socio-demographic and biological variables were not associated with patients not wearing the CCMD, whereas technical quality and user satisfaction were strongly associated.

Association between prosthetic factors and temporomandibular disorders in complete denture wearers.

OBJECTIVE: The purpose of this study was to investigate the prevalence of temporomandibular disorders (TMD) in denture wearers and the association between prosthetic factors and this condition. BACKGROUND: There is no consensus about the relationship between prosthetic factors and TMD among denture wearers. MATERIALS AND METHODS: The sample was composed of 92 patients wearing both maxillary and mandibular complete dentures. The Research Diagnostic Criteria for TMD (RDC/TMD) were adopted for patient examination. Objective evaluation of denture quality was determined by analysis of retention and stability of mandibular denture, interocclusal distance, articulation and occlusion. Association between denture quality and TMD diagnosis was analysed using chi-square and Fisher's exact tests. RESULTS: 37.4% of the patients presented TMD. Denture quality was not significantly associated with the presence of TMD: mandibular retention (p = 0.466); mandibular stability (p = 0.466); interocclusal distance (p = 0.328); centric relation (p = 0.175); and balanced occlusion (p = 0.56). CONCLUSION: Within the scope of this case-controlled cross-sectional study, no robust association between prosthetic factors and TMD was found.

Xerostomia in complete denture wearers: prevalence, clinical findings and impact on oral functions.

OBJECTIVES: To investigate the prevalence of dry mouth in a select sample of edentulous Jordanian older population wearing complete dentures and to evaluate its impact on oral functions. BACKGROUND: The prevalence and impact of Xerostomia as a cofactor in causing denture problems in Jordanians have not been previously investigated. MATERIALS AND METHODS: This study included 455 participants (253 men and 202 women). Perception of dry mouth was measured by a pilot-tested questionnaire. Xerostomic status was confirmed clinically. Complete denture function was also assessed. RESULTS: One hundred and thirty six subjects (29.9%) had reported a subjective feeling of dry mouth with a prevalence of 24.9% in men (n = 63) and 36.1% in women (n = 73) (p < 0.01). 136 of the 145 subjects with satisfactory dentures showed one or more signs suggestive of Xerostomia. The majority of xerostomic participants with different sets of complete dentures were dissatisfied with oral functions (p < 0.05). There was a significant association between dry mouth and increasing age, female gender and smoking status (p < 0.05). CONCLUSION: Among complete denture wearers, Xerostomia is significantly more prevalent in women and associated with increased age and smoking. Xerostomia adversely affects oral functions and overall satisfaction with dentures.

Effect of dentist's clinical experience on treatment satisfaction of a complete denture.

The relationship between the prosthodontic experience of dentists and satisfaction of complete denture wearers remains unknown. To investigate whether a prosthodontist's clinical experience affects treatment satisfaction of a complete denture wearer. From April 2004 to July 2006, we conducted a randomised controlled trial at two centres, including 74 edentulous patients; of these, 32 and 30 were randomly allocated to the ED or ID group, respectively. All the patients rated their satisfaction with dentures, including general satisfaction and satisfaction of chewing ability, speaking, cleaning, stability, retention, comfort and aesthetics. These satisfaction ratings were measured by a 100-mm visual analog scale (VAS). Perceived chewing ability to foods, divided into five grades, was measured using a questionnaire. The mastication index (MI) was calculated for each grade. General satisfaction and satisfaction of speaking, stability and retention were significantly higher in the ED than in the ID group (P = 0·049, 0·003, 0·019 and 0·041, respectively). No significant difference existed between the MI of the ED (71·3 ± 18·4) and ID group (64·1 ± 16·53). However, the perceived chewing ability of grade 5 food, whose texture was the hardest among all the grades, was significantly higher in the ED group than in the ID group. Within its limitations, this study showed that a clinician's prosthodontic experience affects a complete denture wearer's satisfaction ratings.

Short-term complications of implant-supported and combined tooth-implant-supported fixed dental prostheses.

OBJECTIVE: The objective of this clinical study was to evaluate survival and incidence of complications for metal-ceramic and all-ceramic implant-supported fixed dental prostheses (FDPs) and tooth-implant-supported FDPs. MATERIAL AND METHODS: One-hundred and sixty-six FDPs placed in 132 patients from a prospective study were selected for this retrospective analysis. Included were 91 conventional implant-supported FDPs with implant support on both extremities, 27 implant-supported cantilever FDPs, and 48 tooth-implant-supported FDPs. All restorations were veneered with ceramic. Twenty-six FDPs had a zirconia framework and 140 had a metal framework. Kaplan-Meier analysis was performed to estimate FDP success defined as complication-free survival and the Cox regression model was used to isolate risk factors for the most frequent complications. RESULTS: Within a median follow-up of 1 year and 2 months, three failures were caused by a failed implant (n = 2) and by extended chipping of the veneer (n = 1). In contrast with this low incidence of failure was a high incidence of complications including chipping (n = 29), loss of retention (n = 35), and abutment fractures (n = 2). Multivariate survival analysis revealed a significantly greater incidence of chipping for males and a tendency to increased incidence of chipping for zirconia-based FDPs. The incidence of loss of retention tended to be less for tooth-implant-supported FDPs, for which semi-permanent cement was the only significant risk factor, with a hazard ratio of almost 5. CONCLUSIONS: As chipping of the ceramic veneer was the most frequent complication leading to substantial aftercare, improvements of ceramic veneers are desirable for zirconia-based and metal-based FDPs.

Resonance frequency analysis-reliability in third generation instruments: Osstell mentor®

Few studies assess repeatability and reproducibility in registers of resonance frequency analysis (a value of dental implant stability).Objective: Few studies assess repeatability and reproducibility in resonance frequency analyses (implant stability evaluation). This study is aimed at assessing reliability (repeatabilty and reproducibility) in the Osstell Mentor® system using the intraclass correlation coefficient (ICC) as the statistical method.Study Design: ISQ measurements of RFA were carried out by means of the Osstell Mentor® instrument in 58 implants in 19 patients. Six measurements were performed on each implant by means of two different Smart-Pegs (I and II). Three consecutive measurements were registered with each transducer.Results: Average ISQ varied from 72.43 to 72.60 and 73.26 in the first, second and third measurements, respectively with the SamrtPeg I and from 72.98 to 73.26 and 73.74 in the first, second and third measurements, respectively with the SamrtPeg II . Exactly equal values were observed in 10.43 and 12.1% of the cases with Smart-Pegs I and II, respectively. The intraclass correlation coefficient was 0.96 and 0.96 for Smart Pegs I and II, respectively. Repeatability and reproducibility was 0.97 for both Smart-Pegs I and II.Conclusions: The RFA system contributed by Osstell Mentor® renders almost perfect reproducibility and repeatability, as proven by statistical analysis carried out by means of ICC with 95% confidence level. This instrument contributes highly reliable RFA measurements in dental implants (AU)

The clinical and radiographic outcome of immediately loaded mini implants supporting a mandibular overdenture. A 3-year prospective study.

This article aimed to examine the clinical and radiographic outcome of mini dental implants (MDIs) supporting a mandibular overdenture. Twenty-eight patients (16 men and 12 women) complaining from insufficient retention of their mandibular denture received a total of 112 MDIs (four per patient) in the interforaminal area of the mandible using the non-submerged flapless surgical approach. Implants were immediately loaded with mandibular overdentures after implant insertion. Each implant was evaluated at the time of initial prosthetic loading, 6, 12, 24 and 36 months thereafter. Clinical evaluation was performed using plaque index (PI), gingival index (GI), probing depth (PD) and periotest values (PTVs). Radiographic evaluation was performed in terms of vertical (VBLO) and horizontal (HBLO) alveolar bone loss. Cumulative success and survival rates were calculated using life table analysis. Plaque index, GI, PD, VBLO and HBLO increased significantly in the first year after overdenture insertion, and no significant difference between subsequent observations was noted. Periotest values demonstrated no significant difference between observation times. The cumulative survival and success rates of MDIs were 96·4% and 92·9%, respectively. Within the limitations of this study, clinical and radiographic peri-implant tissue responses of immediately loaded MDIs supporting a mandibular overdenture were favourable after 3 years. However, randomised, controlled clinical trials are needed to compare these responses to that of conventional-diameter implants.

The prevalence of denture stomatitis and its predisposing conditions in an older Greek population.

BACKGROUND: Pathology related to complete denture-wearing will remain an important issue because of an increase in the ageing population. OBJECTIVE: To investigate the prevalence and the risk factors for denture-related stomatitis in the edentulous maxilla of older patients with a maxillary complete denture. MATERIAL AND METHODS: One hundred and six patients treated in the Department of Prosthodontics of the Athens Dental School were interviewed and clinically examined. The results were analysed using chi-square tests and multiple logistic regression. RESULTS: Denture stomatitis was recorded in 39.6% of the sample (pinpoint hyperaemia: 17%, diffuse erythema: 16%, papillary hyperplasia: 6.6%). Chi-square tests recorded significant associations between denture stomatitis and the continuous use of dentures (particularly the diffuse erythema type), the increased duration of denture experience and the poor retention of the maxillary denture. Other significant associations were recorded between the increased age of the current denture and pinpoint hyperaemia, and the reduced frequency of denture cleaning and papillary hyperplasia. Multiple logistic analysis revealed that the most important risk factor for denture stomatitis was the continuous use of the denture. CONCLUSION: The prevalence of denture stomatitis was high in denture users. Although many predisposing conditions were recorded, the most important risk factor was the continuous use of the denture. Therefore, appropriate advice on denture maintenance should be provided.

A methodology to study the effects of prosthesis misfit over time: an in vivo model.

PURPOSE: Passive fit of implant-supported superstructures cannot currently be achieved. The aim of this investigation was to create a methodology that can be used to study the effects of prosthesis misfit in humans. MATERIALS AND METHODS: An edentulous patient received two interforaminal implants and a screw-retained bar for the retention of the mandibular denture. A corresponding in vitro model with strain gauges placed mesially and distally, adjacent to the implants, was fabricated to serve as a standardizing control. Over a period of 6 months, a total of 10 measurements on both the in vitro model and in the patient's mouth were conducted with newly fixed strain gauges on the bar. RESULTS: The in vitro experiments showed that no component wear at the abutment-bar interface had occurred and that repositioning of the strain gauges on the bar caused deviations in strain measurements up to 10.55%. In vivo, a reduction in strain development, from 445 to 383 Mum/m, was observed in the initial phase up to 12 weeks after bar insertion. Subsequently, the measurement values increased, and after a period of 24 weeks, they nearly reached the initial strain level (443 microm/m). Only minor changes in strain development of the bar could be detected; these might be a result of limited dynamic loading and the cortical architecture of the surrounding bone. Deviations in measurement accuracy caused by repositioning of the bar strain gauge are a limitation of this technique and should be eliminated in future studies. CONCLUSIONS: The present methodology can be applied to study changes in static implant loading over time in humans.

Clinical studies of fiber-reinforced resin-bonded fixed partial dentures: a systematic review.

In the past decade, follow-up studies on fiber-reinforced composite fixed partial dentures (FRC FPDs) have been described. Combining the results of these studies to draw conclusions about the effectiveness of FRC FPDs is challenging. The objective of this systematic review was to obtain survival rates of FRC FPDs and to explore the relationships between reported survival rates and risk factors. In a literature-selection procedure on the clinical performance of FRC FPDs, 15 studies, reporting on 13 sets of patients, were analyzed. The Kaplan-Meier estimate of the overall survival, based on the data from all sets of patients (n = 435) was 73.4% (69.4-77.4%) at 4.5 yr. Converted survival rates at 2 yr of follow-up showed substantial heterogeneity between studies. It was not possible to build a reliable regression model that indicated risk factors. The technical problems most commonly described were fracture of the FPD and delamination of the veneering composite.

Implant-supported mandibular overdentures retained with a milled bar: a retrospective study.

PURPOSE: The aim of this retrospective study was to evaluate implant survival rate, peri-implant conditions, and prosthodontic maintenance for implant-supported mandibular overdentures rigidly retained with a milled bar. MATERIALS AND METHODS: Patients with 4 interforaminal implants (cylindric or screw-type) supporting an overdenture on a milled bar treated between 1996 and 2004 were asked to participate in a retrospective study. The cumulative implant survival rate and peri-implant conditions (marginal bone loss, pocket depth, Plaque Index, Gingival Index, Bleeding Index, and calculus presence) were evaluated and compared between cylindric and screw-type implants. The incidence and type of prosthodontic maintenance and subjective patient satisfaction rating were also evaluated. RESULTS: Fifty-eight of 67 patients (87.3%) and 232 implants (76 cylindric, 156 screw-type) were available for follow-up examination after a mean period of 59.2 +/- 26.9 months. The cumulative implant survival rate was 99%, and no differences in peri-implant soft tissue conditions were noted between the different implant types used. The cylindric implants showed more pronounced marginal bone resorption than the screw-type implants (1.9 +/- 0.6 mm vs 2.2 +/- 0.6 mm; P = .02) but the difference was not clinically significant. A low incidence of prosthodontic maintenance evenly distributed throughout the overall follow-up period and a high subjective satisfaction rating by the patients were noted. CONCLUSION: Interforaminal screw-type and cylindric implants supporting a milled bar for rigid overdenture anchorage were associated with a high survival rate and excellent peri-implant conditions. The incidence of prosthodontic maintenance was low and evenly distributed throughout the follow-up period as a result of rigid denture stabilization by the milled bar. Rigid anchorage of a mandibular overdenture with a milled bar unites the prosthodontic advantages of removable and fixed prostheses. (Clinical Trial) (More than 50 references.)

Risk factors associated with denture stomatitis in the United States.

BACKGROUND: This study reports denture stomatitis (DS) prevalence from a large USA probability sample from the National Health and Nutrition Examination Survey, 1988-1994 (NHANES III). METHODS: Oral examinations were performed on 3450 individuals 18-90+ years of age (mean: 59.2; SD: 0.50 years), 57.7% male and 42.3% female. Multivariable logistic regression models were fitted for DS using sociodemographic, denture quality, blood analytes, alcohol and tobacco use, history of diabetes, and current antibiotic use as covariates. Odds ratios (OR), adjusted for other covariates in each model (AOR) are presented. RESULTS: Of 3450 removable denture wearers, 963 (27.9%) had DS. DS prevalence was associated with wearing maxillary (AOR: 6.20) and mandibular (AOR: 5.21) complete dentures continuously; smoking >/=15 cigarettes day (maxillary complete: AOR = 1.31; mandibular complete: AOR = 1.50; maxillary partial: AOR = 2.04); vitamin A deficiency (mandibular complete: AOR = 5.97; maxillary partial: AOR = 5.67; mandibular partial: AOR = 24.42). Maxillary dentures with inadequate relines had approximately half the OR of DS than those with adequate relines (maxillary complete: AOR = 0.42; mandibular complete: AOR = 0.50). CONCLUSIONS: Denture stomatitis prevalence is associated with the amount of tissue covered by dentures, low vitamin A levels, cigarette smoking, and constant denture wear.

Quality of removable partial dentures worn by the adult U.S. population.

STATEMENT OF PROBLEMS: Research-based assessments of the quality of removable partial dentures (RPDs), especially within a large patient population, are lacking. PURPOSE: This study evaluated the prevalence and quality of RPDs by use of the National Health and Nutrition Survey (NHANES III) data set. MATERIAL AND METHODS: Estimates of the health and nutritional status of the American population were obtained from the NHANES III data set (1988-1994). Calibrated dentists performed dental examinations on 17,884 adults. If the subject wore an RPD, its quality was assessed with 5 criteria: integrity, tooth wear, the presence of temporary reline material or adhesive, stability, and retention. In this study, the data on RPD defects were used to assess the prevalence of problems. The original population was divided into 4 subgroups: paired RPD data = subjects wearing both maxillary and mandibular RPDs (n = 600 prostheses, 300 maxillary and 300 mandibular); single RPD data = subjects with only one RPD (n = 1003 prostheses, 511 maxillary and 492 mandibular); maxillary versus mandibular RPD data = all subjects with all RPDs (n = 1603 prostheses, 811 maxillary and 792 mandibular); and pooled RPD data = all subjects with a single RPD plus subjects with 2 RPDs, counting only the RPD with the most defects (n = 1303 prostheses, 674 maxillary and 629 mandibular). The subjects were analyzed with descriptive statistics. The distribution of defects in the RPDs was examined for possible associations with chi(2) tests. The paired data for patients with both maxillary and mandibular RPDs were analyzed with Wilcoxon signed rank tests. The prevalence of RPDs as a function of patient age and the association between RPD defects and patient age were analyzed with chi(2) tests. The results were considered highly significant at P<.0001 and significant at P<.05. RESULTS: Of the 17,884 adults who underwent a dental examination, 1306 had RPDs. Three patients were excluded because their records were incomplete, leaving 1303 patients available for analysis. Most of the prostheses examined (65%) had at least 1 defect. Lack of stability was the most prevalent single defect. Distinctions in the type and prevalence of defects were observed between mandibular and maxillary RPDs. Mandibular RPDs had significantly more problems related to retention, whereas maxillary RPDs had significantly more problems related to the presence of reline material and to integrity defects. Tooth wear defects were significantly associated with patient age (P<.0001). Only one third of the RPDs were considered satisfactory according to NHANES III criteria. CONCLUSION: A review of the database used in this study indicated that, in spite of a decline in tooth loss, RPDs are still used in all age cohorts, including young adults. A large number of RPDs were found to have defects.

Resin-bonded bridges by dental undergraduates: three-year follow-up.

This study was conducted to evaluate performance and longevity of resin-bonded bridges in patients treated by undergraduate dental students. A total of 62 bridges had been constructed for 53 patients by the students at the School of Dentistry, Karolinska Institute, between 1989 and 1997. After a mean observation period of 35.3 months retention had been lost in 13.6% of 59 bridges examined (4.6% per year). The debonding rate was greater in the mandible (8.3 %/year) than in the maxilla (2.7 %/year), and greatest in the mandibular anterior region (13.4%). Thirty-nine patients with 46 bridges (27 maxillary and 19 mandibular bridges), underwent more detailed clinical examination. No significant differences in bleeding and pocket depth were found between abutment teeth and controls. Bleeding was more frequent at the approximal than the lingual surfaces of the abutment teeth. A questionnaire revealed high patient satisfaction, the resin-bonded bridges meeting their expectations. The study suggests that resin-bonded bridges are an acceptable alternative to conventional bridges. Successful outcome is dependent on stringent case selection, an abutment preparation designed to establish retention form, and meticulous bonding procedures.

Usage of denture adhesives.

OBJECTIVES: There have been few reports in the dental literature on the number of denture wearers who regularly use denture adhesive. The objectives of this study were to see what the incidence of usage of denture adhesive was by a surveyed edentulous population, to determine the degree of success of its usage and the reasons for its current use or nonuse. METHODS: In this study, 146 patients attending the Adelaide Dental Hospital for denture treatment were surveyed regarding their usage of denture adhesive, using a prepared questionnaire. The surveyed group was divided into three categories--those who had never tried denture adhesive, those who had tried denture adhesive but no longer used it, and those who currently used denture adhesive. RESULTS: In the survey, there were 52 males (35.6%) and 94 females (64.4%) and 96 (65.7%) were over 60 years of age. Of these 78 patients (54.9%) had worn their dentures for 10 years or more, and 26 (17.8%) for 20 years or more. A total of 98 patients (67.1%) had never tried denture adhesive: 48 patients (32.9%) had tried denture adhesive but only 10 (6.9%) currently used it. Various reasons for trying denture adhesive and for its continued use or nonuse were given. CONCLUSIONS: In this study, 52% of patients surveyed saw no need for the use of denture adhesive as they managed their dentures well; 20.5% of patients did not know that denture adhesives existed; and 32.9% had tried denture adhesive but only 6.9% continued to use it on a regular basis.

Long-term experience with telescopically retained overdentures (double crown technique).

To evaluate the long term results of telescopically retained overdentures, 92 patients with a total of 106 overdentures on 236 teeth were examined after two to eleven years. Thirty-three teeth were lost during the follow-up period. A higher tooth survival rate of the double-crowned teeth was found under mandibular overdentures (92%) than under maxillary overdentures (86%) after five years. The palladium-silver-alloy used seemed to be more suitable for telescopic crowns than the use of precious gold-copper-alloys because of tarnishing the latter alloys.

Long-term results of telescopic crown retained dentures--a retrospective study.

The clinical data for 250 telescopic crown retained dentures involving 617 abutment teeth preparations were collected and analysed in a retrospective study to ascertain the survival rate of the dentures and their abutment teeth. During the study period 10.6% of the abutment teeth had to be extracted. An increased number of telescopic crowns significantly improved the longevity of the prostheses and their associated abutment teeth in most denture designs, but this was not found to be the case with bilateral free-end saddle designs without an anterior bounded saddle. The use of more than four abutment teeth did not result in a higher survival rate.

Method for enhancing retention in complete denture bases.

STATEMENT OF PROBLEM: Physical retention of a denture depends on adhesion of a salivary film to its fitting surface and supporting tissues. Adhesion is influenced by many factors. PURPOSE: This study examined the effect of the texture of the fitting surface on denture retention. MATERIAL AND METHODS: According to the method developed, mucosal-supported palatal bases were made for 10 dentate subjects who had no obvious oral disease, history of allergy to dental materials, or palatal mucosal undercuts. A specially designed strain gauge force transducer and a pen-chart recorder were used to record forces that were needed to dislodge the bases from the palate. Forces were recorded 30 times (10/day) for each subject. Similar forces were recorded after the fitting surface of each base was uniformly air-particle abraded under 4 kg/cm2 of pressure for 1 minute with 50-microm grit alumina dust. Data were analyzed with a 2-sample Student t test and a paired t test. RESULTS: Substantial variations for all measurements were observed both between and within subjects. Notwithstanding, these variations, the mean retention of the bases significantly (P <.05) increased by more than 2-fold when the fitting surface was air-particle abraded. These force values were similar to those recorded previously for well-fitting mucosal-supported palatal bases in a separate group of dentate subjects. CONCLUSIONS: While reinforcing the importance of good adaptation of the denture to the tissues, these findings also suggest that an additional improvement in denture retention can be accomplished after the fitting surface is air-particle abraded.