# Polytetrafluoroethylene Isolation of the Periodontal Sulcus for Cementation of Full Veneer Restorations Using a Biologically Oriented Preparation Technique (BOPT): An In Vitro Study

## TL;DR

This study shows that using PTFE tape helps reduce excess cement in dental restorations when a rubber dam can't be used.

## Contribution

The study introduces PTFE tape as an effective alternative for relative isolation during BOPT cementation.

## Key findings

- PTFE tape significantly reduced cement retention compared to no isolation.
- No difference was found between 0.1 mm and 0.2 mm PTFE tape thicknesses.
- The results suggest PTFE is a viable option for isolation in BOPT procedures.

## Abstract

Background: Prosthetic cementation using the biologically oriented preparation technique (BOPT) presents challenges in removing excess cement from the gingival sulcus, due to the absence of a finishing line and the impossibility of using absolute isolation with a rubber dam. This study aimed to evaluate the effectiveness of relative isolation using polytetrafluoroethylene (PTFE) tape in reducing cement retention during BOPT cementation. Methods: Fifteen 3D-printed resin models were created from an intraoral scan of a patient restored with BOPT in both upper central incisors. Each model included removable gingiva. Splinted polymethylmethacrylate (PMMA) provisional crowns were fabricated and cemented with temporary cement. One central incisor was isolated with PTFE (0.1 mm or 0.2 mm), while the contralateral tooth was left unisolated as a control. After debonding, digital scanning and volumetric analysis using root mean square (RMS) deviation were performed to quantify retained cement. Paired t-tests were applied to compare groups. Results: The mean RMS for the PTFE group was 0.1248 ± 0.0519 mm, compared to 0.1973 ± 0.0361 mm in the non-isolated group (p < 0.001). No significant difference was found between PTFE thicknesses of 0.1 mm and 0.2 mm (p = 0.388). Conclusions: PTFE tape is effective for relative isolation when rubber dam placement is not feasible in BOPT restorations. Further clinical studies are recommended to confirm these findings in vivo.