Age-Related Changes in the Nasolabial Angle and Anterior Nasal Spine: A Three-Dimensional Morphometric Study Using Skull Computed Tomography (CT) Scans

Introduction: The anterior nasal spine (ANS) is a thin bony structure located in the maxilla that plays a crucial role in supporting the nasal apex and upper lip, serving as an important reference point in dental and surgical procedures, as well as in craniofacial analyses. Age-related changes, such as bone remodeling, can influence its morphology and, consequently, modify the nasolabial angle, a relevant parameter for assessing aesthetic and functional changes in the face. The objective of this study was to investigate possible changes in the nasolabial angle with advancing age through three-dimensional morphometric analysis of computed tomography scans of human skulls. Methods: The sample consisted of 93 CT scans. Based on age, the individuals were classified into three groups: 18-44 years (young), 45-64 years (middle-aged), and ≥65 years (elderly). The images were segmented using Mimics 18.0 software, allowing three-dimensional reconstruction of the ANS and measurement of the nasolabial angle from three specific anatomical landmarks. Statistical analysis was performed using ANOVA, followed by a Šídák multiple comparisons test, adopting a 5% significance level. Results: The results demonstrated that the nasolabial angle presented significant changes from the young male group vs. the middle-aged female group, tending to become more closed with aging. Furthermore, morphological variations of the ANS (single, bifid, or double) were identified, highlighting its anatomical diversity. Conclusion: It is concluded that the ANS undergoes structural modifications throughout adulthood, as reflected in the nasolabial angle, and that it is a relevant landmark in studies of facial aging, in addition to its clinical value in dental and surgical procedures.