Elsevier

Journal of Dentistry

Volume 35, Issue 12, December 2007, Pages 939-945
Journal of Dentistry

Long-term analysis of telescopic crown retained removable partial dentures: Survival and need for maintenance

https://doi.org/10.1016/j.jdent.2007.09.010Get rights and content

Abstract

Objectives

The aim of this retrospective longitudinal study was to evaluate the clinical long-term survival of telescopic crown retained removable partial dentures (TRPDs), the influencing factors on survival as well as the type and number of necessary treatments during the observation time.

Methods

The study is based on the data of 463 patients who had received a total of 554 TRPDs with a total of 1758 telescopic crowns between 1995 and 2004 in our Dental School. The influence of the patient's gender, location of the denture, number of abutment teeth per telescopic denture, their distribution (Kennedy-class) and the impact of a routinely follow-up programme on the survival probability were analysed.

Results

During the observation period (mean 5.3 ± 2.9 years) 4.7% of the TRPDs ceased functioning and 3.8% of the abutment teeth were extracted. The survival probability after 5 years was 95.1% for the TRPDs and 95.3% for the abutment teeth. No denture with more than four abutments required replacement. Only the covariates number of abutment teeth and patient in-follow-up showed a significant (p < 0.01) influence on the survival probability. 26.9% of the TRPDs needed facing repairs, 34.8% relines, 20.6% loss of cementation of a primary crown and 1% abutment tooth treatment.

Conclusions

Within the limits of a retrospective study it can be concluded that the number of attachments and thorough aftercare have a considerable impact on the long-term success of TRPDs. Though loss of cementation and defects of the facings were significant in number, they did not endanger the long-term success of a TRPD at all.

Introduction

Despite the indisputable success of preventive treatment and prophylaxis in recent years, the need for prosthetic treatment due to tooth loss will continue to increase in relation to the age of the patient. The rate of edentulism among the elderly is, however, continually decreasing and it is anticipated that in 2010 75-year-old patients will still likely to have more than 16 residual teeth on average.1

Apart from implant treatment or even leaving the partially dentate status, a conventional removable partial denture (RPD) is a viable treatment option in these cases. Functional denture stability, good retention, oral comfort and satisfactory aesthetics are important factors for a successful treatment with RPDs.[2], [3], [4], [5] In addition, oral hygiene should be easy to perform and the distribution of the functional loads should be optimized among the abutment teeth and the alveolar ridge.[2], [4], [5] Taking these requirements into consideration, a RPD retained by telescopic crowns (TRPD) on the residual dentition is an alternative treatment option to a conventional clasp retained RPD.[5], [6], [7], [8]

A TRPD has a positive impact on preserving the abutment teeth.8 The principles of tooth preservation are based on a rigid connection between the abutment teeth and the TRPD with mainly axial loading, which reduces any existing mobility.9 In general, two different retention principles are used for TRPDs: parallel-sided inner and outer crowns or conical shaped inner and outer crowns. In the latter group, the degree of taper is kept within a well-defined range of inclination.10

The supposed advantages of a TRPD[6], [7], [9], [10], [11] may, however, be offset by the disadvantages of high treatment costs and treatment requirements within the denture's functional period.10 Loss of cementation and fractures of the artificial teeth are the most common problems in TRPDs.12 As TRPDs are rigidly connected to the abutment teeth, there is an increased risk for tooth fracture.13 Technically, the treatment and laboratory procedures are highly complex,14 which in turn results in higher costs for the patient.

Currently little information is available regarding the long-term survival of TRPDs and their maintenance need.12 The aim of this retrospective longitudinal study was therefore to determine the long-term survival of TRPDs, taking into consideration possible influencing factors as well as treatment needs within the functional period.

Section snippets

Study population

This study investigated patients who received a TRPD between 1995 and 2004 in the Department of Prosthodontics, Justus-Liebig-University Giessen, Germany. Implant-borne dentures and cases with no assessable data available after fitting the denture (n = 90) were excluded. Overall 463 patients (male/female: 224/239; mean age 58.8 ± 11.2 years; range: 21–84 years) with a total of 554 TRPDs retained on 1758 abutment teeth (Table 1) could be evaluated. Table 2 provides an overview of the number of

Conformity of patients in the study and dropouts

None of the parameters tested for conformity showed a significant difference between the study-patients and the dropout-patients (Table 5).

Survival probability of TRPDs and abutment teeth

During the observation period a total of 26 (=4.7%) out of the 554 TRPDs required replacement. In 15 cases the new restoration involved a new TRPD whereas in 11 cases the TRPD had to be replaced by a full denture due to tooth loss. 66 of the 1758 abutment teeth (3.8%) were extracted. The survival probability after 5 years was calculated as 95.1% for the

Study design

This study aimed to evaluate the survival probability and maintenance needs of TRPDs using a retrospective longitudinal study design. Though retrospective studies have natural shortcomings as they have to rely on the data available, they are nevertheless helpful as long as data of higher evidence (e.g. RCTs) are missing. This is especially valid for the topic we investigated.

A general problem of longitudinal studies is their inevitable dropout as it may affect the results if the dropout is not

Conclusions

Within the limits of this retrospective study it can be concluded that the number of attachments and thorough aftercare have a considerable impact on the long-term success of TRPDs. Though loss of cementation and defects of the facings were significant in number and may cause considerable follow-up costs, they did not endanger the further functioning of the TRPDs in any way.

Acknowledgements

We would like to thank Dr. Manfred Hollenhorst of the Department for Documentation, Justus-Liebig-University Computer Centre, Giessen, for his assistance with the statistical analysis.

References (24)

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