Association of Normal Values of Nasolabial Angle and Lip Length with Incisal Display at Rest Position of Lips

Abstract

Objective: To determine correlation between values of nasolabial angle and lip length with

incisal display at rest position of lips.

Methods: This descriptive cross-sectional study was conducted at Institute of Dentistry

LUMHS. Individuals aged between 18 to 40 years visiting for prosthesis of posterior teeth, both

genders, with fully erupted anterior maxillary teeth and well aligned teeth and with intact upper

central incisors, with no significant wear, fractures, or discoloration were included. A

photogrammetric approach was employed to analyze the nasolabial angle, and two photographs

with frontal and lateral views were taken for each participant, with the camera placed 1.5 meters

away at the participant's head height to ensure standardization, which were digitally analyzed,

with the nasolabial angle measured in degrees and the lip length and incisal display measured in

millimeters. Vernier caliper was used for measurement of the lip length from the base of the

nose to the lowest point of the upper lip, and these measurements were cross-referenced with

digital measurements to ensure accuracy. A correlation analysis was assessing the relationship

of nasolabial angle and lip length, with incisal display.