A 25 year longitudinal study of patients treated with removable partial dentures

Longevity of acrylic and cobalt-chromium removable partial dentures-A ten-year retrospective survival analysis of 1246 denture-wearing patients

OBJECTIVES

to assess the survival rates of removable partial dentures (RPDs) and identify factors impacting their longevity.

METHODS

electronic health records were retrieved of patients aged ≥18 who received RPDs between 2010 - 2021 with a follow-up of ≥ three months. Data extracted included demographics, medical history, dental charting, periodontal screening and recording scores, prostheses details and related interventions, including new dentures/denture remakes, and maintenance. Multivariate Mixed-Effect Cox regression was performed to identify potential RPD survival risk factors. Reduced model selection was reached using a backward step-down by comparing the performance of these multivariable models using the ANOVA test.

RESULTS

1893 RPDs from 1246 patients were included, with a median follow-up of 21.8 months (range from 3 to 131.3 months). Three hundred and twelve patients received a maxillary RPD, 460 received a mandibular RPD, and the remaining 474 patients received both maxillary and mandibular RPDs. Metal-based RPDs had a median survival of 73 months (95%CI: 70 - 82) versus 45 months (95% CI: 37-67) for acrylic ones. Multivariable mixed effects Cox model showed that the lifespans of RPDs were longer amongst patients receiving more maintenance care within three months [Hazards Ratio (HR)=0.89 (0.83, 0.96)] and after three months [HR=0.53 (0.46, 0.61)] of denture delivery, patients wearing both maxillary and mandibular RPDs [HR=0.67 (0.52, 0.87)], and patients receiving metal-based RPDs [HR=0.31 (0.23, 0.42)].

CONCLUSIONS

Metal-based dentures, dual arch restoration, and increased maintenance positively impact the survival of RPDs.

CLINICAL SIGNIFICANCE

Adapting consent and warranty practices is advised to reflect RPD performance variations.

Long-term assessment of the periodontal health of removable partial denture wearers: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The long-term effects of wearing removable partial dentures (RPDs) remain unclear.

PURPOSE

This systematic review addressed the question "Is the long-term use of RPDs deleterious to the remaining teeth?"

MATERIAL AND METHODS

This review was guided by the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. Six databases and nonpeer-reviewed literature were searched in April 2024 without language or follow-up restrictions. Only clinical studies evaluating RPD long-term use were included. The risk of bias and evidence certainty were assessed (RoB 2.0; ROBINS-I; GRADE), and meta-analyses were conducted for survival rate and periodontal health (α=.05).

RESULTS

A total of 5577 records were identified, and 46 studies covering data from 4359 prostheses and 4072 participants (mean age 60 ±5.2 years) were included. A low to moderate risk of bias was found. A 5-year survival rate of 95.1% (ER=0.951; 95% CI=0.900 to 0.977; P<.001) and 91.7% (ER=0.917; 95% CI=0.870 to 0.948; P<.001) was found for cast-clasp RPD and RPDs retained by telescopic crowns respectively, with no difference between them (P=.71). Abutments (OR=1.99, 95% CI=1.32 to 3.01; P=.001) and nonvital teeth (HR=2.961; 95% CI=2.023 to 4.335; P<.001) presented a higher risk of extraction after 5 years. Tooth mobility (P=.98) and probing depth (P=.50) remained unchanged, while the gingival index increased (MD=0.477 (95% CI=0.12 to 0.83; P=.008).

CONCLUSIONS

A high survival rate was found for both cast-clasp RPD and RPDs retained by telescopic crowns, with few periodontal changes to the remaining teeth.

Outcomes of resin-bonded attachments for removable dental prostheses

PURPOSE

This clinical study aimed to evaluate the outcomes of resin-bonded attachments (RBAs) for precision-retained removable dental prostheses (RDPs) after at least two years of clinical maintenance.

METHODS

Since December 1998, 205 RBAs (44 bonded to posterior teeth, 161 to anterior teeth) have been inserted in 123 patients (62 females and 61 males; mean age, 63.6 ± 9.6 years) who were recalled annually. The abutment teeth underwent a minimally invasive preparation limited to the enamel. RBAs were cast in a cobalt-chromium alloy with a minimum thickness of 0.5 mm and adhesively luted with a luting composite resin (Panavia 21 Ex or Panavia V5, Kuraray, Japan). We evaluated caries activity, plaque index, periodontal condition, and tooth vitality. The Kaplan-Meier survival curves were used to account for the reasons for failure.

RESULTS

The mean observation time of RBAs until the last recall visit was 84.5 ± 51.3 months (range, 3.6-270.6). During the observation period, 33 RBAs debonded in 27 patients (16.1%). The 10-year success rate according to the Kaplan-Meier analysis was 58.4%, which dropped to 46.2% after 15 years of observation if debonding was considered a failure. If rebonded RBAs were regarded as surviving, the 10- and 15-year survival rates would be 68.3% and 61%, respectively.

CONCLUSIONS

The use of RBAs for precision-retained RDPs appears to be a promising alternative to conventionally retained RDPs. As reported in the literature, the survival rate and frequency of complications were comparable with those of conventional crown-retained attachments for RDPs.

A technique to guide implant placement with the long axis parallel to the path of insertion of removable partial dentures

This article describes a novel technique that allows the planning and placing of dental implants with their long axis parallel to a path of insertion chosen for a prospective removable partial denture. The technique is straightforward, uses digital technologies efficiently, and enables prosthetically driven implant placement. It also optimizes the outcome when dental implants are used in association with removable partial dentures.

Postinsertion adjustment appointments and their association with cast removable partial denture survival

STATEMENT OF PROBLEM

Successful outcomes with cast removable partial dentures (RPDs) are dependent on adequate fabrication and adjustments at the delivery appointment. Evaluation of the number and frequency of postinsertion follow-up appointments helps determine whether the prosthesis continues to fit comfortably and whether function and esthetics continue to be satisfactory. Reports on the number of appointments and frequency and type of adjustments required for RPDs following insertion are sparse.

PURPOSE

The purpose of this university-based population study was to determine the number of appointments and type of adjustments following RPD insertion and their association with patient demographics, type of RPD, and denture survival.

MATERIAL AND METHODS

This retrospective clinical study examined the records of 257 patients at the University of Toronto, Faculty Dentistry, wearing 308 RPDs inserted between 2013 and 2014 with a 5-year follow-up. The outcome measures investigated included postinsertion appointments, type of adjustments, and denture survival.

RESULTS

A total of 48.1% of the dentures (19.5% tissue supported; and 28.6% tooth supported) were maxillary, and 51.9% (34.7% tissue supported; and 17.2% tooth supported) mandibular. Most patients (68.9%) had 1 to 3 postinsertion appointments, with 78.6% having no major adjustments. Twenty-six dentures failed (failure rate 8.4%), with the failure-free time estimated at 4.58 years (95% confidence interval (CI) 4.42-4.73 years, Kaplan-Meier survival analysis). Failed dentures were significantly associated with more minor adjustments (Mean (M)=4.12, SD=3.90, Kruskal-Wallis (K-W) P=.027; OR=1.18; 95% CI 1.05-1.32, P=.006). More minor adjustments were needed for mandibular dentures (multivariable Poisson regression (MPR) P=.003) compared with maxillary dentures. More major adjustments were needed for maxillary dentures (MPR P=.030) compared with mandibular dentures. More minor and major adjustments were needed for dentures that were remade from within 5 years to beyond 10 years compared with first time denture wearers (MPR P<.001). Patients with musculoskeletal disorders required a significantly higher number of minor adjustments (M=3.67, MPR P<.001) and appointments (M=3.87, MPR P<.001) than those without these disorders.

CONCLUSIONS

The 5-year survival of RPDs following insertion was estimated at 91.6%. Most patients required 1 to 3 appointments after insertion. Mandibular RPDs required significantly more minor adjustments, and maxillary RPDs more major adjustments. More minor and major adjustments were needed for dentures that were remade at any time previously compared with first time denture wearers.

Comparison of the impact of two types of removable partial dentures on the periodontal health of the remaining teeth: A prospective clinical study

OBJECTIVE

To evaluate and compare the impact of two removable partial dentures (acrylic removable partial denture [ARPD] and metallic removable partial denture [MRPD]) on periodontal tissues of the remaining teeth in the first 12 months of denture use.

MATERIALS AND METHODS

This prospective clinical study included 40 patients, of which 20 received ARPDs, 20 received MRPDs, nine in the maxilla, and 11 in the mandible each. The patients were 45-65 years old; 24 were females, and 16 were males. Patients' demographic details, clinical indicators of periodontal complications, and biochemical measurement of Hs-C-reactive protein (CRP) and alkaline phosphatase (ALP) were considered. One-way analysis of covariance and Friedman were used to measure the differences in clinical periodontal parameters between the two types of dentures.

RESULTS

The significant findings were: Plaque index (PLAQ) scores for abutment teeth were higher in MRPD wearers (mean = 12.15) than ARPD wearers (mean = 10.45), whereas ARPD users had significantly higher mean bleeding on probing (BOP) values (mean = 1.5) than MRPD users (mean = 0.00); mobility of abutment teeth showed no significant differences; timeline comparisons showed a significant increase in the percentage of nonabutment teeth mobility in ARPD users (p = .028) compared with MRPD users over the same follow-up period (p = .102).

CONCLUSIONS

For a short-term period of 1 year, periodontal and mobility parameters have no significant impact on the abutment and nonabutment teeth of ARPD and MRPD users. Moreover, biochemical markers (CRP and ALP) for periodontal inflammation exhibited no significant difference in both types of dentures.

Artificial intelligence models for tooth-supported fixed and removable prosthodontics: A systematic review

STATEMENT OF PROBLEM

Artificial intelligence applications are increasing in prosthodontics. Still, the current development and performance of artificial intelligence in prosthodontic applications has not yet been systematically documented and analyzed.

PURPOSE

The purpose of this systematic review was to assess the performance of the artificial intelligence models in prosthodontics for tooth shade selection, automation of restoration design, mapping the tooth preparation finishing line, optimizing the manufacturing casting, predicting facial changes in patients with removable prostheses, and designing removable partial dentures.

MATERIAL AND METHODS

An electronic systematic review was performed in MEDLINE/PubMed, EMBASE, Web of Science, Cochrane, and Scopus. A manual search was also conducted. Studies with artificial intelligence models were selected based on 6 criteria: tooth shade selection, automated fabrication of dental restorations, mapping the finishing line of tooth preparations, optimizing the manufacturing casting process, predicting facial changes in patients with removable prostheses, and designing removable partial dentures. Two investigators independently evaluated the quality assessment of the studies by applying the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies (nonrandomized experimental studies). A third investigator was consulted to resolve lack of consensus.

RESULTS

A total of 36 articles were reviewed and classified into 6 groups based on the application of the artificial intelligence model. One article reported on the development of an artificial intelligence model for tooth shade selection, reporting better shade matching than with conventional visual selection; 14 articles reported on the feasibility of automated design of dental restorations using different artificial intelligence models; 1 artificial intelligence model was able to mark the margin line without manual interaction with an average accuracy ranging from 90.6% to 97.4%; 2 investigations developed artificial intelligence algorithms for optimizing the manufacturing casting process, reporting an improvement of the design process, minimizing the porosity on the cast metal, and reducing the overall manufacturing time; 1 study proposed an artificial intelligence model that was able to predict facial changes in patients using removable prostheses; and 17 investigations that developed clinical decision support, expert systems for designing removable partial dentures for clinicians and educational purposes, computer-aided learning with video interactive programs for student learning, and automated removable partial denture design.

CONCLUSIONS

Artificial intelligence models have shown the potential for providing a reliable diagnostic tool for tooth shade selection, automated restoration design, mapping the preparation finishing line, optimizing the manufacturing casting, predicting facial changes in patients with removable prostheses, and designing removable partial dentures, but they are still in development. Additional studies are needed to further develop and assess their clinical performance.

Insufficient Evidence to Ascertain the Long-Term Survival of PEEK Dental Prostheses: A Systematic Review of Clinical Studies

Introduction: Polyetheretherketone (PEEK) is a polymer that is used in the construction of orthopaedic and dental implants. It is also used to construct removable and fixed dental prostheses due to its superior mechanical and esthetic properties compared to conventional materials. This systematic review aims to analyse and appraise the literature concerning PEEK dental prostheses critically. Methods: The following focused question was constructed ‘Are dental prostheses made of PEEK inferior to those made of other materials in terms of clinical- and patient-reported outcomes?’. The CONSORT (Consolidated Standards of Reporting Trials) tool was used for the quality assessment of the randomised clinical trials. The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) quality assessment tool was used to assess the quality of observational studies and the case reports were evaluated using the CARE (Case Report) guidelines. Results: A total of 12 studies were included in this review. Two case studies received an overall grade of medium and the overall quality of six studies was graded as ‘low’. All three observational studies and the only randomised controlled trial received scores of ‘medium’. Conclusion: PEEK-based dental prostheses may provide a viable and more esthetic alternative to conventional prosthodontic appliances. However, within the limitations of this study is the evidence to ascertain the long-term viability of PEEK-based dental prostheses. Future studies should focus on conducting large-scale, multicenter trials to compare the survival rate of PEEK prostheses to that of conventionally available prosthodontic appliances.

Short strategic implants for mandibular removable partial dentures: One-year results from a pilot randomized crossover abutment type study

Objectives

The present pilot study analyzed two abutment types (a retentive ball and a non‐retentive dome) in implant‐assisted removable partial dentures (IARPDs) on 6 mm short implants with respect to clinical, radiological, and patient‐reported outcomes (PROs), during the first year.

Materials and Methods

Two implants were placed bilaterally in mandibular molar sites, converting existing free‐end removable partial dentures (RPDs) to IARPDs. Twelve subjects were randomized to initially receive either the dome (Group A, n = 6) or the ball abutment (Group B, n = 6). After eight weeks, the abutments were exchanged. After another 8 weeks, the participants were given the choice of one of the abutments. Mean values and standard deviations (SD) were calculated, and random‐effect linear regression analyses were applied to analyze marginal bone level alterations and PROs (α < .05).

Results

Twelve participants were included in the study; however, one dropout occurred. Patient ratings increased significantly in both study groups. The majority of the participants (82%) ultimately chose the ball abutment. The implant survival rate was 100%, and the success rate was 90.9% twelve months after implant placement (mean peri‐implant bone‐loss: −1.2; SD: 0.6 mm) without a statistically significant difference between the study groups, in terms of clinical‐ and radiological outcomes.

Conclusion

Placing 6 mm short implants at mandibular molar sites of RPD wearers seems to be a viable treatment option, based on this investigation with a short‐term follow‐up. Although only minor differences between the two abutments were observed, patients seem to prefer the ball over the dome abutment.

Short-term effect of thermoplastic resin removable partial dentures on periodontal health: a randomized cross-over trial

PURPOSE

This study aimed to compare the short-term effects of thermoplastic resin removable partial dentures (TR-RPDs), referred to as non-metal clasp dentures, with those of metal-clasp-retained RPDs (MC-RPDs) on the periodontal health of abutment teeth.

METHODS

A randomized cross-over trial was conducted in 28 partially dentate patients. Participants were randomized into two groups and received MC-RPDs followed by TR-RPDs, or vice versa, for 3 months. Periodontal clinical parameters, such as the plaque index, gingival index, probing pocket depth, tooth mobility, and microbiological status of the abutment teeth, were evaluated at the delivery and 3 months after using each RPD.

RESULTS

Of the 28 patients enrolled, 24 (mean age, 67.3 years) completed the trial, and 55 abutment teeth were evaluated. The periodontal condition of the abutment teeth did not deteriorate after 3 months of using both types of RPDs. There was no statistically significant difference in the plaque index, gingival index, probing pocket depth, tooth mobility, and the red complex bacteria between TR- and MC-RPDs (p >0.05). The Periotest value for TR-RPDs was significantly lower than that for MC-RPDs (p <0.05). However, this difference was not clinically significant.

CONCLUSIONS

These results suggest that the influence of TR-RPDs on the periodontal health of abutment teeth was limited within 3 months of use.　Trial registration number: The study protocol was registered at UMIN-CTR (UMIN000007310).

Telescopic overdenture for oral rehabilitation of partially edentulous patient

A case report describing the rehabilitation of a patient presenting with partially edentulous arches and compromised abutment teeth has been described. The aim of this study was to restore function and esthetics and uplift the psychological status of the patient by fabrication of a fixed removable prosthesis using the existing abutment teeth as telescopic overdenture.

Fluoride-Releasing Effect of a Modified Resin Denture Containing S-PRG Fillers on Salivary Fluoride Retention: A Randomized Clinical Study

This study aimed to evaluate the clinical effect of a resin denture base containing 20wt% surface prereacted glass ionomer (S-PRG) fillers on saliva fluoride concentrations as a surrogate evaluation of caries control. The study was a double-blind randomized clinical trial with a total of 110 participants aged 35-60 years who wore a removable partial resin denture for 1.5 years. Subjects were randomly assigned to receive a partial resin denture fabricated either with or without 20wt% S-PRG fillers (n = 55 per group). After 14 days of wearing the dentures, 5,000 ppm fluoride gel was applied nightly on both sides of the denture before storing it in a denture box overnight every night for 1.5 years. The salivary fluoride concentration was measured at baseline, on days 1, 14, and 15, and at 3 months and 1.5 years of wearing the denture. A significant increase in salivary fluoride concentration in the S-PRG denture group was observed from baseline to day 1, followed by a significant decrease to an approximate baseline level. After recharge with 5,000 ppm fluoride gel, salivary fluoride increased markedly on day 15 and remained elevated at month 3 through to 1.5 years. The resin denture base containing 20wt% S-PRG fillers demonstrated an initial fluoride release that increased saliva fluoride concentrations, but the fluoride release from within the material was short lived. The long-term effect of sustained fluoride release from the denture when combined with a regular fluoride recharge regimen may be beneficial for caries prevention.

Biological complications of removable dental prostheses in the moderately reduced dentition: a systematic literature review

OBJECTIVES

The aim of the present study was a systematic review and subsequent meta-analysis on biological complications of removable prostheses in the moderately reduced dentition.

MATERIALS AND METHODS

A systematic literature search in established medical databases (MEDLINE, EMBASE, BIOSIS, SciSearch, Cochrane, FIZ Technik Web) and a hand search of relevant dental journals was conducted. The search terms were relevant MeSH terms, free search terms, and combinations of the two. The search included randomized controlled trials, prospective and retrospective studies with data on biological complications of removable dental prostheses in the moderately reduced dentition with at least 15 participants, an observation period of at least 2 years, and a drop-out rate of less than 25%. The selection of relevant publications was carried out at the title, abstract, and full-text level by at least two of the authors involved. The publications included were tabulated and analyzed.

RESULTS

Of the original 12,994 matches, 1923 were analyzed by title, 650 by abstract, and 111 according to the full text. A total of 42 publications were ultimately included. The following parameters were evaluated.

TOOTH LOSS

Results varied, depending on the observation period, between 0 and 18.1% for clasp-retained removable dental prostheses (RDPs), between 5.5 and 29% for attachment-retained RDPs, and between 5.5 and 51.7% for double crown-retained RDPs.

CARIES

Results varied, depending on the observation period, between 0 and 32.7% for clasp-retained RDPs, between 1.8 and 29% for attachment-retained RDPs, and between 1.8 and 16.4% for double crown-retained RDPs.

ENDODONTIC TREATMENT

Results varied, depending on the observation period, between 3.5 and 19.2% for clasp-retained RDPs, between 6.9 and 16.4% for attachment-retained RDPs, and between 0.6 and 13.9% for double crown-retained RDPs.

TOOTH FRACTURE

Results varied, depending on the observation period, between 1.7 and 5.3% for clasp-retained RDPs, between 12.7 and 40% for attachment-retained RDPs, and between 0.4 and 4.4% for double crown-retained RDPs.

TOOTH MOBILITY

There were no changes or improvements for clasp-retained RDPs. The better the pre-treatment and supportive care is, the smaller the differences are. For double crown-retained RDPs, a slight increase was found in one study. The results for the parameters probing depth and radiological bone loss were inconclusive.

GINGIVAL RECESSION

Gingival recession seemed to be favored by a mandibular sublingual bar. Compared to fixed restorations, removable restorations seemed to be associated with a more pronounced need for dental treatment. Stringent pre-treatment and supportive care reduced the complication rates.

CONCLUSIONS

Heterogeneous study designs and data analyses rendered a meta-analysis impossible, so that an evaluation at the highest level of evidence could not be performed.

CLINICAL RELEVANCE

Within the limitations of this study, it would be correct to state that removable dental prostheses require intensive maintenance. Suitable pre-treatment and supportive care can lower the complication rates, in the absence of which they constitute trigger factors for (additional) biological complications.

Surface modification of CoCr alloys by electrochemical reduction of diazonium salts

Tailoring the surface chemistry of CoCr alloys is of tremendous interest in many biomedical applications. In this work, we show that CoCr can be modified by diazonium electrografting provided the surface is not homogeneously covered with an oxide layer. Cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) show the electrografting of a poly(aminophenylene) (PAP) layer on CoCr when treated at a reductive potential (CoCr-0.5 V), whereas no PAP film was formed on CoCrOCP and CoCr1 V, treated at open circuit and anodic potentials respectively. Based on XPS results, we attributed the electrografting to the formation of carbide bonds between PAP and the inhomogeneous thin oxide layer of CoCr-0.5 V. We then show an example of application of PAP coatings on CoCr and prove that the presence of a PAP coating on CoCr-0.5 V results in a 5-fold increase of the adherence of poly methyl methacrylate (PMMA) to PAP-coated CoCr compared to uncoated samples; this is of prime significance to improving the long-term stability of dental prostheses. These findings support the importance of reducing the oxide layer for effective functionalization of metal oxides with aryl diazonium salts and suggest a promising surface modification approach for biomedical applications.

Longitudinal Improvement in Periodontal Parameters between RPD Abutment Teeth with Direct and Indirect Retainers, after Periodontal Therapy

PURPOSE

To evaluate the effect of basic periodontal treatment on clinical periodontal parameters associated with abutment teeth of patients with mandibular Kennedy class I removable partial dentures (RPD) 18 months after treatment.

MATERIALS AND METHODS

Thirty patients with periodontal disease were treated and evaluated according to the following periodontal parameters: visible plaque index (VPI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), clinical attachment loss (CAL), and keratinized mucosa (KM). These parameters were compared between abutment teeth with direct and indirect retainers at baseline, and after 6 and 18 months. Data were analyzed by Friedman Test and Wilcoxon Test for all variables.

RESULTS

Most patients (n = 26; 86.7%) included in the study were female and had a mean age of 61 years (±7.54). Results showed that VPI and BOP decreased over time, and that VPI values were higher in abutment teeth with direct retainers (p = 0.001). There was a reduction in PD after 6 months, which was maintained up to 18 months. In general, abutment teeth with direct retainers had significantly higher values for PD, GR, and CAL (p = 0.029). Data also indicated that the parameters for VPI, BOP, and PD improved; however, abutment teeth with direct retainers presented smaller improvements, compared with abutment teeth with indirect retainers, which presented significant improvements for almost all variables.

CONCLUSION

Periodontal treatment and oral hygiene care of patients were adequate for maintenance of adequate periodontal conditions, regardless of the use of prostheses.

Is the shortened dental arch still a satisfactory option?

Aims Dental practitioners may hold the view that missing posterior teeth should be replaced to ensure a healthy masticatory system and satisfactory oral function. However, the shortened dental arch (SDA) concept is still in use, but after 35 years is it acceptable? This review searches the literature for the evidence and opinions regarding the suitability of the SDA as a current treatment modality.Methods Medline and PubMed databases were searched for relevant terms, all the abstracts were assessed and articles selected according to the pre-set exclusion and inclusion criteria.Results The search yielded 1,895 articles and after the assessment of the abstracts and application of the exclusion and inclusion criteria, 44 articles were selected for this review. These included 11 cohort studies, two longitudinal studies, two animal studies, three cross sectional studies, eight clinical studies and 18 case control studies. There appears to be a trend over the past three decades for more papers to be opposed to the SDA concept.Conclusion Evidence that the SDA causes pathology is lacking. Clinicians, healthcare authorities and patients have shown favourable attitudes towards the SDA and this continues, although there is an increase in studies opposing the concept and some are dissatisfied with this option. The concept remains viable particularly for the medically compromised patient or where restorations are considered unsuitable but further more specific studies are warranted.

A Clinical Retrospective Study of Distal Extension Removable Partial Denture with Implant Surveyed Bridge or Stud Type Attachment

This study was performed to make comparative analysis of the clinical findings between the two different types of the implant-assisted removable partial dentures: removable partial dentures using implant surveyed bridge as an abutment (ISBRPD) and overdenture type of removable partial denture using implant attachment (IARPD). Implant cumulative survival rate, marginal bone resorption, probing depth, peri-implant inflammation, bleeding, plaque, calculus, and complications were evaluated on 24 patients who were treated with implants in conjunction with removable partial denture and have used them for at least 1 year (ISCRPD: n = 12; IARPD: n = 12). There was no failed implant and all implants were functioning without clinical mobility. Marginal bone loss of ISCRPD (1.44 ± 0.57 mm) was significantly lower than that of IARPD (p < 0.05). There was no significant difference in probing depth, peri-implant inflammation, bleeding, and plaque between the two groups (p > 0.05), while the calculus was significantly more observed in ISCRPD group than in IARPD group (p < 0.05). The retention loss of IARPD was the most common complication. Within the limits of the present study, it was found that well-planned ISBRPD was clinically appropriate. Longitudinal and systematic clinical studies are necessary to confirm these results.

Prognosis of double crown-retained removable dental prostheses compared with clasp-retained removable dental prostheses: A retrospective study

PURPOSE

The present study compared the clinical prognosis of double crown-retained removable dental prostheses (D-DRPs) with that of clasp-retained removable dental prostheses (C-RDPs).

METHODS

Clinical records of 201 patients who had received 52 D-RDPs with 144 abutment teeth (D-teeth) and 199 C-RDPs with 399 abutment teeth (C-teeth) at the Prosthetic Dentistry Clinic in Hokkaido University Hospital between April 2005 and June 2015 were analyzed. Survival and complication probabilities of the two types of prostheses and abutment teeth were evaluated using the Kaplan-Meier method and compared using the log-rank test. Cox regression analysis was used to determine the impact of covariates on abutment teeth survival and complications such as gender, age, type of retainer, Eichner classification, jaw, type of tooth, endodontic therapy performed, type of edentulous space, and presence of opposing teeth.

RESULTS

Statistical analysis showed no significant differences between the two types of prostheses in terms of prostheses survival, prostheses complication, and abutment teeth survival. However, a significant difference was observed for complications of abutment teeth. Decementation was the most frequent cause of failure, which occurred in 76.9% of D-teeth and 28.3% of C-teeth. Patient's age, jaw, endodontic therapy performed, and type of edentulous space affected the survival of abutment teeth, whereas the type of retainer and edentulous space affected complications of abutment teeth.

CONCLUSION

The prognosis of both types of prostheses was considered to be acceptable. Although D-RDP had lower complication-free rates for abutment teeth, most of the observed complications were decementation, which was considered to be reparable.

Epidemiological Data and Survival Rate of Removable Partial Dentures

INTRODUCTION

The use of removable partial denture (RPD) is considered as low-cost and common treatment option to rehabilitate edentulous areas.

AIM

This study aimed to investigate the epidemiological data of patients rehabilitated with removable partial denture (RPD) in order to assess treatment survival rate and failures.

MATERIALS AND METHODS

Epidemiological data and medical records of patients treated with RPD between 2007 and 2012 at the RPD discipline of a Brazilian University (Aracatuba Dental School- UNESP) were evaluated as well as dental records of patients who underwent RPD treatments (fabrication or repairs) between 2000 and 2010. Factors such as gender, age, presence of systemic disease, main complaint, edentulous arch, period and cause of denture replacement and the prosthesis characteristics were recorded. The chi-square test was used to assess the differences between the variables and the Kaplan Meyer to assess the survival of the RPDs evaluated.

RESULTS

A total of 324 maxillary RPD and 432 mandibular RPD were fabricated. Most of the patients were women aging 41 to 60-year-old. The number of mandibular RPD Kennedy class I (26%) was statistically higher for the maxillary arch (p<.05). There was no association between main complaint to gender or the presence of systemic disease. The lingual plate was the most common major connector used in the mandible (32%). The main reason for altering the design of replaced RPDs were changes during treatment plan.

CONCLUSION

The number of patients who require RPD is large; most of RPDs are Kennedy Class I. A good treatment plan is very important for achieving a positive treatment outcome, and it is strictly related to the survival rate.

Partial denture metal framework may harbor potentially pathogenic bacteria

PURPOSE

The aim of this study was to characterize and compare bacterial diversity on the removable partial denture (RPD) framework over time.

MATERIALS AND METHODS

This descriptive pilot study included five women who were rehabilitated with free-end mandibular RPD. The biofilm on T-bar clasps were collected 1 week (t₁) and 4 months (t₂) after the RPD was inserted (t₀). Bacterial 16S rDNA was extracted and PCR amplified. Amplicons were cloned; clones were submitted to cycle sequencing, and sequences were compared with GenBank (98% similarity).

RESULTS

A total of 180 sequences with more than 499 bp were obtained. Two phylogenetic trees with 84 (t₁) and 96 (t₂) clones represented the bacteria biofilm at the RPD. About 93% of the obtained phylotypes fell into 25 known species for t₁ and 17 for t₂, which were grouped in 5 phyla: Firmicutes (t₁=82%; t₂=60%), Actinobacteria (t₁=5%; t₂=10%), Bacteroidetes (t₁=2%; t₂=6%), Proteobacteria (t₁=10%; t₂=15%) and Fusobacteria (t₁=1%; t₂=8%). The libraries also include 3 novel phylotypes for t₁ and 11 for t₂. Library t₂ differs from t₁ (P=.004); t₁ is a subset of the t₂ (P=.052). Periodontal pathogens, such as F. nucleatum, were more prevalent in t₂.

CONCLUSION

The biofilm composition of the RPD metal clasps changed along time after RPD wearing. The RPD framework may act as a reservoir for potentially pathogenic bacteria and the RPD wearers may benefit from regular follow-up visits and strategies on prosthesis-related oral health instructions.

Clinical evaluation of removable partial dentures on the periodontal health of abutment teeth: a retrospective study

The aim of this retrospective study was to evaluate the effect of removable partial dentures in periodontal abutment teeth in relation to the type of denture support and design of RPD in a five-year worn period. Methods : A total of 64 patients with removable partial dentures (RPDs), participated in this study. It were examined ninety-one RPDs. There were seventy-five RPDs with clasp-retained and sixteenth were RPDs with attachments. There were 28 females and 36 males, aged between 40-64 years, 41 maxillary and 50 mandible RPDs. For each subjects the following data were collected: denture design, denture support, and Kennedy classification. Abutment teeth were assessed for plaque index (PI), calculus index (CI), blending on probing (BOP), probing depth (PD), gingival recession (GR), tooth mobility (TM). Level of significance was set at p<0.05. Results : According to denture support of RPD, BOP, PD, PI, GR, CI and TM-index showed no statistically significant difference. Based on the denture design of RPD’s, BOP, PD, PI, CI, and TM-index proved no statistically significant difference. Except GR-index according to denture design confirmed statistically significant difference in RPD with clasp p<0.01. The higher values of all periodontal parameter as BOP, PD, PI, CI and TM were in patients with RPD’s with claps comparing with RPD’s with attachment. Conclusion : RPD’s with clasp increased level of gingival inflammation in regions covered by the dentures and below the clasp arms in abutment teeth.

Contemporary denture base resins: Part 1

Provision of partial and complete dentures constructed from resin is commonplace and a satisfactory outcome requires the consideration of the properties of the resin, the oral tissues and prosthodontic principles. Conventional acrylic resin has been widely adopted as a popular denture base material since the 1930s. In this first of a two-part series, the benefits and shortcomings of acrylic resin are discussed alongside contemporary 'enhancements' to the material which can improve its properties. In the second part of the series, flexible and other alternative denture base resins, soft-linings, adverse effects of denture base materials and maintenance will be discussed.

CLINICAL RELEVANCE

Knowledge of contemporary denture base resin systems will help to achieve optimal outcomes in removable prosthodontics.

Oral rehabilitation considerations for partially edentulous periodontal patients

Traditional tooth-supported and implant-supported fixed/removable restorations are currently used to replace teeth lost due to periodontal disease. This article reviews the existing literature for oral rehabilitation of partially edentulous periodontal patients with various designs of removable dental prosthesis (RDP), fixed dental prosthesis (FDP) and implant-supported single crown (SC), by addressing their (a) general features, (b) survival and complication rates, along with considerations for treatment planning in periodontal patients, and (c) preference by patients. To answer these issues, relevant articles were searched and critically analyzed, and their data were extracted. Data reviewed indicated that despite many advantages, implant-supported restorations have higher complication rates than tooth-supported restorations. Systematic reviews on conventional RDPs are lacking, but existing literature reviews provide limited evidence suggesting the use of RDPs with design modifications along with strict periodontal care in periodontal patients. Numerous systematic reviews on conventional FDPs and implant-supported restorations provide a moderate level of evidence favoring their survival in periodontal patients; however, for long-term success of these restorations, the patient's periodontal condition needs to be stabilized. In terms of patient preference, no restoration is superior, as they all are governed by their cost, advantages, and disadvantages. Thus, in the wake of existing weak evidence for prosthodontic rehabilitation of periodontal patients by these restorations (especially, conventional RDPs and for FDPs and SCs in implant-supported restorations), longitudinal studies with standardized treatment protocol and methodology are needed to evaluate and compare tooth-supported and implant-supported restorations in periodontal patients with regard to survival rates, cost, maintenance, and patient-centered outcomes.

Prevalence of removable partial dentures users treated at the Aracatuba Dental School-UNESP

OBJECTIVES

The aim of this study was to evaluate the frequency of removable partial dentures (RPD) at the Aracatuba Dental School.

METHODS

The study was conducted by analysing 412 clinical history of patients attended at the RPD clinics in the period from 2000 to 2007.

RESULTS

412 charts were analysed: 148 (35.9%) men and 264 (64.1%) women. The mean age was 53.8 years (men) and 52.4 years (women). A total of 556 dentures were made; of these, 233 (41.90%) were maxillary and 323 (58.09%) were mandibular dentures. The most frequent Kennedy classification found was Class III (maxilla) and Class I (mandible). In the maxilla, 55% (126) of the major connectors were of the anterior-posterior palatal bar, while in the mandible, 64% (202) were the lingual bar. As regards the claps, 401 were circumferential and 318 were bar claps.

CONCLUSION

The mean age of the patients was 52.9 years with higher prevalence of female patients; the most frequent Kennedy's classification was Class I in mandible and Class III in maxilla; the most common major connector was anterior-posterior palatal bar for maxilla and lingual bar for mandible; the circumferential clasps were the most common retainer used in both jaws.

Case-control study on the survival of abutment teeth of partially dentate patients

OBJECTIVES

Due to the scarce amount of data available, a retrospective analysis of patients treated with removable dental prostheses (RDPs) was performed. The aim of the trial was to evaluate the rate of repairs and failures of attachment-retained RDPs (AR-RDPs) compared to clasp-retained RDPs (CR-RDPs) with respect to cofactors (e.g., type of loading). In this respect, two hypotheses were proposed: AR-RDPs are more prone to repairs than CR-RDPs, and AR-RDPs are more prone to fail than CR-RDPs.

MATERIALS AND METHOD

Two hundred three patients treated with 135 AR-RDPs and 68 CR-RDPs between 1994 and 2006 were evaluated in this trial. The dental treatment was carried out in the clinical training course of senior students. Kaplan-Meier estimates were calculated for the primary end point (repairs) and for the secondary end point (failures).

RESULTS

The survival of CR-RDPs and AR-RDPs did show significant differences regarding repairs (p = 0.034) but not with regard to failures (p = 0.169). Prostheses of the non-axially loaded group showed no significant differences in the frequency of repairs and failures.

CONCLUSIONS

Technical complications occurred more frequently in the CR-RDP group. Taking the higher observation time in the AR-RDP group into account, CR-RDPs are more prone to repairs, especially to those with technical background (e.g., fracture of the metal framework).

CLINICAL RELEVANCE

The use of crowns with rod attachments on tilted teeth seems to be an appropriate treatment approach in order to simplify removable dental prosthesis design.

Functional evaluation of oral rehabilitation with removable partial dentures after five years

Most removable partial denture (RPD) wearers are satisfied with their prostheses, but the factors that influence satisfaction and acceptance are still not determined.

OBJECTIVE

This study explored technical, biological, and satisfaction variables for the functioning of RPDs after five years, and compared the evaluation by the patient and by the clinician.

MATERIAL AND METHODS

Fifty adults (39 females, 11 males) were re-examined after five years of RPD service. Data were collected through clinical examination and a structured questionnaire to record the conditions of supporting soft tissues, prosthesis acceptance and technical characteristics, mastication, esthetics, comfort, hygiene, and need for professional intervention. Data were analyzed by descriptive statistics and Spearman correlation.

RESULTS

More than 50% of patients classified their RPDs as excellent regarding retention, mastication, esthetics, comfort, and hygiene. In the professional evaluation, retention and stability were considered excellent in more than 66% of cases, and hygiene of teeth and prostheses was considered good in 52% and 46%, respectively. The metallic framework and acrylic base were considered adapted in 92% of cases. Prosthesis acceptance was associated with retention, mastication, esthetics, hygiene, and comfort evaluated by the patient, and with retention, stability, and condition of the framework evaluated by the clinician. Retention and mastication/comfort evaluated by the patient had moderate positive correlation with retention and stability measured by the clinician. There was no association of hygiene evaluation by the patient and by the clinician.

CONCLUSIONS

After five years, the oral rehabilitation with RPDs was satisfactory for most cases. There was correspondence between retention/retention and mastication-comfort/stability variables evaluated by the patient and by the clinician. Oral and prosthesis hygiene were not related.

Implants in conjunction with removable partial dentures: a literature review

Although the benefits of implant-borne removable prostheses are readily apparent for the fully edentulous patient and have been well documented, there is a paucity of studies concerning the combination of implants with removable partial dentures in partially edentulous patients. The aim of this article is to review the literature regarding implants with removable partial dentures and evaluate the evidence for this clinical approach. A MEDLINE/PubMed search from 1990 to 2006, focusing on the use of implants with removable partial dentures and related features, was supplemented with a hand search to identify relevant peer-reviewed English articles published in dental journals and textbooks on removable partial dentures.

Prognosis for Abutment Teeth of Removable Dentures: A Retrospective Study

PURPOSE

This retrospective study evaluates the clinical success of conical crown-retained removable dentures.

MATERIALS AND METHODS

Ninety-seven patients were treated with 97 dentures at the University of Frankfurt, Department of Prosthodontics, between 1993 and 2000. The average observation period was 4.9 +/- 2.8 years. The dentures were supported by 445 natural abutment teeth. To evaluate the long-term success of the restorations, the variables abutment loss, tooth mobility, mean probing depths, and radiological bone loss were used. Data were obtained by one clinical examiner at baseline, by systematic evaluation of patient records, and at clinical re-examinations. Survival-time methods were used to analyze time-to-event data. Specifically, the Cox model with frailty term was applied to account for correlations between intra-patient survival data. Thirty abutment teeth had to be extracted during the observation period.

RESULTS

Statistical analysis showed no significant effects of the variables tooth mobility (p= 0.42), mean probing depths (p= 0.23), and radiological bone loss (p= 0.59) on the time to tooth extraction. For the non-extracted abutment teeth significant changes during time for the variables tooth mobility (p < 0.0001) and radiological bone loss (p= 0.0240) were observed.

CONCLUSION

Removable partial dentures retained by conical crowns have a favorable clinical prognosis.

An evaluation of the effects of two distal extension removable partial denture designs on tooth stabilization and periodontal health

A 30-month follow-up study was conducted on 36 patients to evaluate the effects of the lingual plate as a major connector in distally extended removable partial dentures (RPDs) on tooth stabilization. At the same time, the study evaluated the effects of lingual plate-type RPDs and lingual bar-type RPDs on periodontal health. The most striking finding of the study was that, with the exception of gingival recession (GR), periodontal conditions improved with both types of RPDs. At the end of 30 months, there were significant differences in plaque index, GR and tooth mobility (TM) values between treatment groups (P < 0.05). Plaque accumulation was greater in the lingual plate treatment group; however, this did not result in periodontal breakdown. There were no statistically significant differences between treatment groups with respect to pocket depth, gingival index or attachment loss (P > 0.05). Moreover, patients treated with lingual plate-type RPDs demonstrated less TM when compared with patients treated with lingual bar-type RPDs at the end of 30 months follow-up. Overall study findings established that with adequate checks on oral and denture hygiene at regular intervals, patients with RPDs may even experience improved periodontal health. Moreover, the clinical interpretation of decreased TM observed in patients treated with lingual plate-type RPDs may be questionable as the plaque accumulation was greater in the lingual plate treatment group inspite of periodic recalls.

An in vitro comparison of retentive force and deformation of acetal resin and cobalt-chromium clasps

STATEMENT OF PROBLEM

The use of metal clasps on anterior teeth may cause esthetic problems. Recently, acetal resins have been used as an alternative tooth-colored denture clasp material to improve esthetics. However, there are few studies to support acetal resin use.

PURPOSE

The purpose of this in vitro study was to compare the retentive force and deformation of acetal resin and cobalt-chromium clasps after 36 months of simulated clinical use.

MATERIAL AND METHODS

Forty clasps each of acetal resin (1.2 or 2.0 mm thick) and cobalt-chromium (Dentorium)(1.2 mm thick) were fabricated using half-round standard prefabricated clasp patterns. The groups were further subdivided (n=10) into the type of tooth (premolar or molar metal model) and undercut (0.25 mm or 0.50 mm). The retentive force of the clasps was measured in distilled water by a specially designed insertion-removal testing apparatus with intervals corresponding to 0, 6, 12, 18, 24, 30, and 36 months of simulated clinical use of a removable partial denture. The distance between the clasp tips (mm) was measured with a microscope before and after the insertion-removal testing procedure. Comparison of the mean values of the retentive force (gram force) of the clasps and the distance (mm) between the clasp tips was conducted with 3-way analysis of variance and a Least Significant Difference (LSD) multiple range test (alpha=.05).

RESULTS

The mean values of tensile load required to dislodge acetal resin clasps with 1.2-mm thickness (111.6 g or 0.11 N) and with 2.0-mm thickness (178.4 g or 1.75 N) was significantly lower than that to dislodge Co-Cr clasps (694.1 g or 6.81 N) (P<.001). The retentive force needed to dislodge all 3 types of clasps was significantly lower for the molar than premolar models and also lower for the models with 0.25-mm undercuts than for those with 0.50-mm undercuts (P<.001). After 36 months of simulated clinical use, there was evidence of deformation in the cobalt-chromium clasps but no deformation noted for the acetal resin clasps. The retentive force of cobalt-chromium clasps (297.4 g or 2.91 N) after deformation remained significantly higher (P<.001) than the retentive force of acetal resin clasps that were 1.2 mm (110.7 g or 1.08 N) and 2.0 mm thick (177.5 g or 1.74 N), respectively.

CONCLUSION

Within the limitations of this study, the results suggest that both thicknesses of acetal resin clasps evaluated required less force for insertion and removal than Co-Cr clasps over a simulated 36-month period.

Finite element contact stress analysis of the RPD abutment tooth and periodontal ligament

OBJECTIVES

The purpose of this study was to determine the influence of the occlusal rest position in removable partial dentures on the displacement of the abutment tooth and the stress distribution in the periodontal ligament (PL).

METHODS

We constructed three-dimensional finite element models of the mandibular first and second premolars. A layer of the PL and a mesial or distal occlusal rest were produced on the second premolar as an abutment. A zero displacement was prescribed on the outer surface of the PL and the first premolar. In each simulation, the rest was moved 0.05 mm vertically to the apical direction, with or without restriction of horizontal movements. We simulated the contact phenomena on the abutment surfaces, and calculated the movements of the abutment and stress distributions in the PL.

RESULTS

We observed a maximum distal displacement of 42 microm at the buccal cusp of the abutment and a principal compressive stress of 0.35 MPa in the PL when the abutment was vertically loaded by a distal rest that was allowed to move horizontally. However, the displacements and stresses were relatively small, and were all within the physiological limitations of the tissues. The restriction of the horizontal movement of the rests was effective in reducing the horizontal displacements of the abutment, regardless of the rest position.

CONCLUSIONS

The single vertical load exerted from either the mesial or distal rest on the abutment was unlikely to cause any mechanical damage to its supporting tissues.

The combination syndrome: a literature review

Although combination syndrome is recognized by many clinicians, documented observations seem to be rare. The aim of this article was to critically review the literature regarding combination syndrome to evaluate the evidence for this concept. A search of the dental literature with Medline/PubMed through July 2002, focusing on the combination syndrome and related features, was undertaken and combined with a hand search of older references and textbooks on removable prosthodontics.

Treatment with removable partial dentures: a longitudinal study. Part I

The aim of this study was to evaluate the effectiveness of an oral rehabilitation by removable partial denture (RPD). Between 1983 and 1994, 629 patients were provided with an RPD at the Dental School of the Université catholique de Louvain. All the RPDs were constructed with a cobalt-chromium framework. All the treatments were provided by dental students under the supervision of clinical instructors. At recall time (1998-2000), 269 patients could not be reached neither by telephone nor by mail and 27 had died. Consequently, 333 patients were called for clinical examination and 254 of these (76.3%) actually attended. For a total of 292 RPDs fitted for these 254 patients, 218 (74.7%) were still being worn at the time of the check-up. Seventy-four dentures were considered to be 'failures', either because they were replaced by another RPD or by a complete denture, or because they had actually never been worn. The statistical analysis (Mantel-Haenszel and Kaplan-Meier) shows that the number of failures is significantly higher at the lower jaw compared with the upper jaw. Most of the failures are attributable to RPDs with free-end saddles and, in particular, to class I mandibular dentures. The patients are wearing their denture(s) mostly continuously (63.6%) and award a high degree of satisfaction to their denture. In general, the results recorded may be considered as very satisfactory, all the more so as we have no regular recall procedures established at our school and as check-up asked for spontaneously by the patients in the course of the period of observation are most of the time occasional or non-existent.

Treatment with removable partial dentures: a longitudinal study. Part II

The aim of this study was to evaluate the effectiveness of an oral rehabilitation by removable partial denture (RPD). Between 1983 and 1994, 629 patients were provided with an RPD at the Dental School of the Université catholique de Louvain. All the RPDs were constructed with a cobalt-chromium framework. All the treatments were provided by dental students under the supervision of clinical instructors. At recall time (1998-2000), 269 patients could not be reached neither by telephone nor by mail and 27 had died. Consequently, 333 patients were called for clinical examination and 254 of these (76.3%) actually attended. For a total of 292 RPDs checked 1893 persistent teeth were listed, with 804 serving as abutments; more than half (57.6%) of these were crowned, for which 51 debondings were recorded. For the period of observation we listed 79 abutments lost (37 at the upper jaw and 42 at the lower jaw), i.e. 9.8% of the total number of abutments. No relation could be established between the type of the abutments (natural or crowned teeth) and the losses observed (Test of Mantel-Haenszel: P=0.9496). In the upper jaw, the percentage of abutments lost was significantly higher in the presence of free-end edentulous areas as compared with bounded edentulous areas (Test of Mantel-Haenszel: P=0.0002); this difference does not appear for the lower jaws (P=0.9558). If we deduct the 25 abutments related with the 11 non-worn RPDs and the 79 abutments lost, no change becomes apparent for 92.2% of the maxillary abutments and for 85.8% of the mandibular abutments. For the 1089 other teeth, we observed the loss of 40 teeth and the appearance of caries or new fillings for 95 teeth. The fractures of cast clasps represent 3.4%.

The effect of three different periodontal pre-treatment procedures on the success of telescopic removable partial dentures

In this prospective study, 120 teeth consisting of maxillary and mandibular canines and premolars were divided into three groups each containing 40 teeth. The teeth were assigned randomly in quadrants to three different periodontal treatment protocols. The first group was treated with professional prophylaxis only. The second group received additional deep scaling. With the third group, additional surgical periodontal flap surgery and scaling was performed. Both papillary bleeding index (PBI) and probing depth (PD) were evaluated before, during and after treatment. During the subsequent prosthetic treatment phase all teeth were then used as telescope abutments supporting a removable prosthesis. The documentation of the attachment level (AL) was then used as a clinical parameter. One year after the incorporation of telescopic removable partial dentures (RPDs), PD, PBI and AL were again evaluated. The resulting periodontal parameters were compared between the different groups using the general linear model (GLM) repeated measures and the Kruskal-Wallis test for non-parametric variables. Differences within the three treatment groups were determined using the t-test, e.g. the Wilcoxon test for dependent variables (P < 0.05). A significant decrease in inflammatory indices (PBI) was found for all types of periodontal treatment (P < 0.03 for all groups). Additionally, the reduction in PD was significant for all of the three groups (P < 0.001 for all groups). The greatest reduction in PD was observed in the group in which a surgical approach was used. Evaluation of the attachment level after the incorporation of the telescopic RPDs showed that tooth position did not influence the periodontal prognosis and that the use of telescopic RPDs exerted no ascertainable negative influence on the periodontium of the abutment teeth.

After Kennedy

Edward Kennedy's book Partial Denture Construction was published in 1928. A number of the principles that he advocated are still taught, albeit in a modified manner, although the background reasoning supporting those principles has changed somewhat. This paper highlights some of those principles and makes the point that several of them do not appear to have achieved wide acceptance over 70 years later.