In Vitro Assessment of Tooth Reduction in Incisors, Canines, and Bicuspids Using Horizontal (Chamfer) and Vertical (BOPT and BOPTm) Finishing Lines.

INTRODUCTION

The selection of the finishing line for dental abutment preparation is influenced by various factors such as the restorative material, esthetic demands, procedural simplicity, and the clinician's experience. However, fundamental principles of tooth preparation, including the preservation of tooth structure, retention form, abutment strength, and margin integrity, are paramount in ensuring predictable and successful prosthodontic outcomes.

OBJECTIVE

This study aims to evaluate the extent of tooth reduction in upper central incisors, canines, and premolars when three abutment preparation techniques-horizontal (chamfer) and vertical (biologically oriented preparation technique (BOPT) and modified BOPT (BOPTm))-are applied.

MATERIALS AND METHODS

Ninety upper maxillary dental models were used, subdivided into three groups: 30 for right central incisors, 30 for right canines, and 30 for right first premolars. Each group was further divided based on the finishing line applied: horizontal (chamfer), vertical (BOPT), and modified vertical (BOPTm). Tooth reduction was quantified by subtracting the volume of the unprepared tooth from that of the prepared tooth. Statistical differences between the groups were analyzed using univariate analysis of variance (ANOVA) with a significance level set at 0.05.

RESULTS

Tooth shape significantly influenced the amount of dental tissue removed. For square-shaped teeth, the volume of reduction was relatively consistent across all techniques. However, in triangular-shaped teeth, the choice of technique notably impacted the amount of tooth reduction. Among the finishing lines, the BOPT technique resulted in the least tooth reduction in both incisors and canines, while the modified BOPT (BOPTm) was the most aggressive. No significant differences were observed in the premolar group. Additionally, both chamfer and modified BOPT lines required less tooth reduction in premolars compared to incisors and canines. The BOPT technique did not show significant differences in tooth reduction across the different tooth types.

CONCLUSION

The BOPT finishing line was the least invasive in terms of tooth reduction for incisors and canines, while the modified BOPT technique (BOPTm) resulted in more aggressive tooth preparation. In the premolar group, both chamfer and modified BOPT lines required less tooth reduction compared to the incisors and canines. No significant variations in reduction were observed when the BOPT technique was applied to different tooth types.