Evaluation of Perceptual and Anthropometrical Facial Changes According to Increase in Vertical Dimension of Occlusion

For restorative demands, increased vertical dimension of occlusion (VDO) is sometimes necessary, as facial changes can be perceptible.

This study aimed to evaluate the perception of facial change due to increased VDO and associated soft tissue changes using 3D-scanned facial images.

Forty participants with healthy dentition and no loss of VDO were recruited. The VDO was increased by 2, 4, 6 and 8 mm on a semi-adjustable articulator after maxillomandibular impressions. Facebow transfers were taken for each participant to create a personalised device. 3D facial scans were taken with the mandibular occlusal device in place, creating facial capture files from frontal, lateral and anteroposterior views for each scanned data. Sixty evaluators were recruited to consecutively cross-compare maximal intercuspal captures with increased VDO. To evaluate soft tissue changes with increased VDO, facial measurements, total face height, lower face height, lip width, lip height and nasolabial angle were measured thrice in 3D scan images using computer-aided design software. Statistical analysis entailed one-way repeated-measures analysis of variance (α = 0.05).

A 4-mm increase in the VDO showed the highest perceptibility for facial change, varying among evaluator groups. Total face height, lower face height and nasolabial angle increased with VDO, while lip width and height decreased. Each soft tissue measurement differed significantly (p < 0.05).

For 3D-scanned facial changes, a 4-mm increase in VDO was the most perceptible difference. Increased VDO affects facial changes.