Beschreibung
Double-crown anchored telescopic dentures on natural abutment teeth are considered the standard treatment in Germany, depending on the findings. It is an established treatment option for the restoration of partially edentulous residual dentition configurations and has been used in everyday dental treatment for decades. The aim of the present retrospective study was to determine modulating factors influencing the survival probabilities of telescopic dentures within their functional period and up to the time of the first restoration procedure, as well as the survival probability of the corresponding abutment teeth. Furthermore, the causes of functional loss as well as the reasons for extraction of the abutment teeth and the different prosthetic restoration measures were determined. The study took place in an independent dental practice to also allow comparison with the university data already predominant in the literature.
The statistical analysis of 318 double-crown anchored telescopic prostheses on 994 natural abutment teeth, which were placed in 249 patients between 2010 and 2021, was performed. The Survival time analyses were performed according to the KAPLAN-MEIER and COX methods.
The defined target event of loss of function or new fabrication occurred in 10.69% (n = 34) of the prostheses within the observation period. Conversion to total prosthesis represented the most common reason for loss of function in more than 60% of the cases. The mean survival time was 10.05 ± 0.31 years, and the 5- and 10-year survival rates were 91.10% and 55.60%, respectively. The factors of “jaw localisation”, “periodontal prosthesis design” and “number of abutment teeth” showed a significant influence on the survival probability of telescopic prostheses (p < 0.05). There were better survival probabilities and longer mean survival time for maxillary telescopic prostheses compared to mandibular prostheses. Opposite results were recorded for telescopic dentures in the cover-denture design and a low number of abutments. The risk of functional loss was almost four times higher for cover-denture prostheses than for a periodontally friendly telescopic prosthesis design and decreased by approximately 56% with increasing number of integrated abutment teeth.
An initial aftercare procedure occurred in 79.25% (n = 252) of the restorations. The most frequently required procedures were "chairside" treatments that could be performed directly by the dentist (removal of pressure points: 40.08%, recementation of the primary crown: 18.25%, friction reduction: 9.52%). The 90% survival probability was undercut after 0.011 years (4 days) and the 50% survival probability after 0.45 years (5 months and 12 days). The age factor showed a significant effect on the survival time to the first reconstructive intervention (p < 0.05). With increasing patient age, the risk of a first corrective measure also increased by 1.3% per year.
The target event of extraction occurred in 10.70% (n = 106) of the documented abutment teeth. Advanced periodontal loss was considered the main reason for extraction, accounting for more than 30%. The mean survival time of the abutment teeth was 9.95 ± 0.19 years and the survival rate after five and ten years was 88.70%/ and 58.60%, respectively. The factors of “opposing jaw dentition”, “periodontal prosthesis design”, and “vitality of abutment teeth” showed significant influence on the survival probability of abutment teeth (p < 0.05). In addition, the factors “age” and “tooth group” showed statistical significance in the multifactorial analysis using COX regression. Abutment teeth with an antagonistic combined prosthetic restoration were almost twice as likely to be extracted compared with the reference category of removable prosthesis. In addition, a cover denture design and a negative vitality status had a negative effect. With increasing patient age at prosthesis insertion, the extraction risk of abutment teeth increased by 2.1% per year, and premolars possessed a good 100% increased risk of loss compared with anterior teeth.
The results obtained in this study underline the established therapeutic success of double-crown anchored telescopic prostheses on natural abutment teeth. It can be concluded that the quality standard is comparable between a university dental clinic and an independent dental practice.
