# Occlusal contact area changes with different retention protocols using T-Scan III: An observational study

## TL;DR

This study compared how two types of clear retainers affect bite contacts over time using the T-Scan III system in orthodontic patients.

## Contribution

The study introduces a comparison of occlusal contact changes between Essix and Occless Essix retainers using the T-Scan III system.

## Key findings

- Occless Essix increased posterior contact intensity and decreased anterior contact intensity after three months.
- Essix retainers showed increased anterior contact intensity and decreased posterior contact intensity.
- No statistically significant differences were found between the two retainer types after three months.

## Abstract

The retention phase in orthodontics is essential for maintaining corrected occlusion and preventing relapse. Clear retainers like Essix are popular for their aesthetics and affordability, but their occlusal coverage might impact anterior and posterior contacts. Modified versions, such as Occless Essix, have been introduced to address these concerns. The aim of this study was to compare occlusal changes over time between Essix and Occless Essix retainers using the T-scan III system.

This analytical observational study involved 30 orthodontic patients treated with MBT 0.022-inch brackets and first premolar extractions. Patients were divided into two groups: one with Essix retainers and the other with Occless Essix retainers. Occlusal contacts and their intensities in anterior and posterior regions were recorded immediately after debonding (T0) and three months later (T1) using the T-scan III system. Statistical analysis used Mann-Whitney, T-test, and Chi-square tests, with significance set at 5%.

After three months, the Occless Essix group showed increased posterior contact intensity and a slight decrease in anterior contact intensity. Conversely, the Essix group had increased anterior contact intensity and decreased posterior contact intensity. These changes were not statistically significant (P=0.17). The Occless Essix group had an increased number of posterior occlusal contacts and a decreased number of anterior contacts, while the Essix group showed a slight increase in anterior contacts. These changes were not statistically significant (P<0.05).

There were no significant differences between Essix and Occless Essix retainers regarding changes in occlusal force intensities or the number of occlusal contacts after three months.