EFFECTIVENESS OF BIOLOGICALLY-ORIENTED TOOTH PREPARATION TECHNIQUES FOR FIXED PROSTHODONTIC RESTORATIONS: ANALYSIS OF SYSTEMATIC REVIEW DATA

Abstract

Retrospective evaluation of systematic reviews’ data devoted to the clinical effectiveness and feasibility of biologically oriented preparation techniques provides, on one hand, the opportunity to highlight those advantages of the method that can currently be considered as the most evidence-based, and, on the other hand, to identify aspects that remain insufficiently studied and require further investigation. This contributes to defining directions for future research related to shoulderless and preservation-oriented preparation strategies. Objective. To analyze data from available targeted systematic reviews regarding the feasibility and effectiveness of biologically oriented tooth preparation approaches for fixed prosthodontic restorations, and to determine differences in clinical outcomes between shoulderless and shoulder-based preparation techniques across various evaluation parameters. Methods. Study was designed as a retrospective literature review with content analysis of data presented in targeted systematic reviews. Analyzed reviews included studies reporting quantitative or standardized clinical assessment of periodontal tissue conditions in the area of prepared abutment teeth (gingival index, bleeding on probing, probing pocket depth, marginal soft- tissue stability), as well as survival and functional success rates of restorations and the prevalence of biological and mechanical complications. Results. Targeted literature search identified 6 systematic reviews addressing the effectiveness and clinical implications of biologically oriented, vertical, and shoulderless preparation techniques. According to the synthesized data, biologically oriented preparation demonstrated periodontal tissue stability at the abutment teeth areas, and survival and clinical success rates of fixed restorations comparable to those associated with traditional horizontal finish line designs. Conclusions. Across the analyzed systematic reviews, notable advantage of biologically oriented preparation was presented as reduced likelihood of gingival recession development, which may be interpreted as particularly relevant clinical effect for anterior and esthetically critical regions. Although survival and success rates of fixed prosthodontic restorations were not significantly influenced by the presence or absence of a cervical finish line, mechanical complications were more frequently reported in horizontal finish line designs than in vertical shoulderless designs. Biologically oriented preparation may be considered as viable alternative to conventional tooth reduction approaches, particularly in cases where preservation of sound tooth structure and optimization of the gingival profile are clinically important. However, additional designed randomized controlled trials of specific standard are required before this technique can be recommended for routine clinical application.