# Assessment of lip morphology changes after bimaxillary orthognathic surgery using stereophotogrammetry

## TL;DR

This study used 3D imaging to assess how upper and lower lip shapes changed after bimaxillary orthognathic surgery over time.

## Contribution

The study introduces the use of stereophotogrammetry to evaluate lip morphology changes after bimaxillary orthognathic surgery.

## Key findings

- A significant decrease in lower lip height, surface, and area was observed 6 months post-surgery.
- Upper lip area increased significantly 6 months after surgery.
- Lip measurements remained stable from 6 months to 1 year post-surgery.

## Abstract

This study aimed to evaluate changes in upper and lower lip morphology after bimaxillary orthognathic surgery using stereophotogrammetry at the preoperative (T0) and postoperative periods of 6 months (T1) and 1 year (T2). For this purpose, 3D images of 11 patients (9 women and 2 men), with an average age of 33.5 years, who underwent surgery in hospitals associated with the Residency Training Program, School of Dentistry of Ribeirão Preto, University of São Paulo, from 2013 to 2019, were analyzed. The software Vectra M3 was used to calculate linear measurements, distance from lip surfaces, and areas. A significant decrease in the lower lip height (p = 0.0621), surface (p = 0.0435), and area (p = 0.0042), as well as an increase in upper lip area (p = 0.029), were observed from T0 to T1. All measurements remained stable from T1 to T2. Additionally, the ages of patients were correlated with the variables at T0, T1, and T2, and the data showed a strong correlation with height and distance of the lower lip vermilion, as well as lip width, particularly at T2. In conclusion, stereophotogrammetry proved to be a valuable tool for assessing soft tissue changes, revealing a significant increase in upper lip area and a decrease in lower lip area, as well as height, and distance from its surface.