# Comparison of three conventional impression techniques for flabby tissues with intraoral digital scans

## TL;DR

This study compares traditional dental impression methods for flabby tissues against digital scanning to determine which is most accurate.

## Contribution

The study introduces a direct comparison of three conventional impression techniques with intraoral digital scanning for flabby ridges.

## Key findings

- The Window Tray Technique (WTT) produced the most accurate impressions for flabby ridges.
- Digital scans showed comparable accuracy to the best conventional methods.
- The Single-Step Mucocompressive Technique (SMT) had the lowest accuracy among conventional methods.

## Abstract

Accurate impression making for flabby anterior maxillary ridges in edentulous patients remains challenging with conventional techniques,
necessitating comparison of their trueness against intraoral digital scanning. Hence, the present study included twenty patients with
maxillary edentulism and Siebert Class I or II anterior flabby ridges were included in this crossover clinical study. Four impression methods
were performed for each participant: 1) Single-Step Mucocompressive Technique (SMT) with polyvinyl siloxane (PVS) in a stock tray; 2) Window
Tray Technique (WTT) using a custom tray with zinc oxide eugenol and light-body PVS; 3) Modified Mucostatic Technique (MMT) with a spaced
custom tray and light-body PVS; and 4) Intraoral Digital Scan (IDS) using a structured light scanner. The trueness of each technique was
evaluated by superimposing the digital models onto the RSM and calculating the root mean square error (RMSE) in micrometers (µ).
The window tray technique produced the most accurate impressions of flabby ridges.