# Evaluation of Gingival Sulcus Width Gain After Nd: YAG Laser and Astringent Retraction Paste Using Intraoral and Laboratory STL Analysis: A Pilot Split-Mouth Study

## TL;DR

This study compares two methods for widening the gum sulcus to improve dental impressions, finding both effective but with differences in measurement depending on the scanner used.

## Contribution

The study introduces a novel split-mouth design using intraoral and laboratory STL analysis to evaluate sulcus width gain from two soft tissue displacement methods.

## Key findings

- Both Nd: YAG laser and astringent retraction paste achieved sulcus width gains above the clinical threshold of 0.20 mm.
- The laboratory scanner recorded significantly higher sulcus width measurements compared to the intraoral scanner.
- No statistically significant difference was found between the two displacement methods.

## Abstract

Background/Objectives: Advancements in digital dentistry have led to new approaches for soft tissue management aimed at improving impression accuracy. This pilot split-mouth study included a single 39-year-old male patient with 19 abutment teeth (114 measurement points). Sulcus width gain was measured at six standardized points per abutment tooth (mesio-buccal, centro-buccal, disto-buccal, disto-oral, centro-oral, mesio-oral) using Exocad software. Methods: Nineteen abutment teeth (114 measurement sections) from one patient were included in a randomized split-mouth design. Gingival displacement was performed either with a Nd: YAG laser or astringent retraction paste. Sulcus width gain was measured at six standardized points per abutment using Exocad software version 3.1 on superimposed STL files obtained by intraoral (IOS) and laboratory (LABSCAN) scanners. Statistical analysis was conducted in JASP (α = 0.05). Results: Both gingival displacement methods achieved sufficient sulcus widening above the clinical threshold of 0.20 mm. Mean gains ranged from 0.270 mm (LASER, IOS) to 0.378 mm (PASTE, LABSCAN). Intergroup comparisons revealed no statistically significant differences between the two gingival displacement methods (p > 0.05), whereas a significant difference was found between scanning modalities (p < 0.001), with higher values recorded for the laboratory scanner. The results should be interpreted cautiously due to the pilot design and limited sample size. Conclusions: Both techniques proved clinically effective for soft tissue displacement, with the laboratory scanner yielding higher sulcus width measurements. As a preliminary investigation, these findings should be interpreted cautiously due to the pilot nature of the study and the inclusion of a single participant.