# Quantitative 3D Evaluation of Facial Soft Tissue Modifications Following Complete Denture Treatment in Edentulous Patients: A Prospective Before–After Study

## TL;DR

This study uses 3D facial scans to show that complete dentures improve facial soft-tissue appearance in toothless patients, especially around the lips and mouth.

## Contribution

The study introduces a structured-light 3D scanning method to objectively quantify facial changes after complete denture treatment in edentulous patients.

## Key findings

- Complete dentures significantly increased upper and lower lip thickness in relaxed posture.
- The nasolabial angle decreased, indicating a more aesthetically favorable facial profile.
- Mouth width increased in maximal intercuspation following denture treatment.

## Abstract

Background: Three-dimensional (3D) facial scanning is an objective, non-invasive method for quantifying facial soft-tissue changes following complete denture (CD) rehabilitation. Reliable quantification of these changes in completely edentulous patients can support more predictable aesthetic and functional outcomes. Methods: This prospective before–after observational study included 30 completely edentulous patients (12 men, 18 women; age 48–87 years; mean ± SD: 67.8 ± 9.2 years) who received new maxillary and mandibular CDs. Structured-light 3D facial scans were obtained at baseline (edentulous, without dentures) and post-rehabilitation with dentures in place, in relaxed posture (RP) and maximal intercuspation (MI). Sixty-five validated anthropometric landmarks were analyzed. Primary outcomes were lower facial height (Sn-Gn), nasolabial angle (Cm-Sn-Ls), lower facial convexity (Ls-Li-Pg), mouth width (Ch-Ch), and upper vermilion height (Ls-Sto). Pre–post changes were assessed using paired-sample tests (p < 0.05). Results: Thirty-four of 65 parameters (52.3%) demonstrated significant post-treatment changes (p < 0.05), mainly in the perioral and lower facial regions. The reported parameters were selected due to their clinical relevance in evaluating perioral support and facial profile changes after complete denture treatment. In RP, upper lip thickness increased from 3.69 ± 0.97 mm to 4.96 ± 1.11 mm (Δ = +1.27 mm; p < 0.0001) and lower lip thickness from 6.18 ± 2.69 mm to 7.36 ± 1.52 mm (Δ = +1.18 mm; p = 0.0408). The nasolabial angle decreased from 116.08 ± 9.17° to 108.06 ± 9.56° (Δ = −8.02°; p = 0.0016). In MI, mouth width increased from 55.72 ± 3.43 mm to 57.97 ± 3.13 mm (Δ = +2.25 mm; p = 0.0102). Conclusions: Complete denture rehabilitation produces measurable, clinically relevant improvements in facial soft-tissue morphology in completely edentulous patients, particularly affecting lip support, mouth width, and the nasolabial profile. Structured-light 3D facial scanning provides a reproducible approach to objective outcome assessment and may support individualized denture design.