Correlation of Arch Width and Vertical Facial Morphology in Untreated Adults at a Tertiary Care Centre: A Cross-sectional Study

Introduction: The vertical dimension of a face is crucial in determining facial aesthetics and harmony. It is important for the orthodontist to understand the relationship between dental arch width and facial morphology for correct diagnosis and proper treatment plan. Aim: To determine the relationship between the vertical face pattern, dental arch width and also, to compare arch widths among both untreated female and male adults. Materials and Methods: This quantitative cross-sectional study was conducted in the Department of Orthodontics and Dentofacial Orthopaedics, at Sharad Pawar Dental College, Sawangi, Wardha, Maharashtra, India. The duration of the study was one month, from June 2019 to July 2019. Dental casts and lateral cephalograms were collected from 50 untreated adults (25 males and 25 females), aged between 18-30 years, who had minimal spacing, crowding and no crossbite. On every patient's cephalogram, the angle between the plane of the mandible to the cranial base anterior Sella Nasion (SN) angle was calculated. Intercanine, intermolar, and interpremolar widths were measured on dental casts. Females and males arch width were compared. The significance of the differences was assessed using Student's t -test, one-way Analysis of Variance (ANOVA) test and regression analysis. Results: The mean age of male study participants in the study was 24.44 +/- 5.04 years, whereas, mean age of females was 24.88 +/- 3.08 years. There were 25 males and 25 females of 1830 years with mean age of 24 and 25 years, respectively. Arch widths of males were found to be significantly greater than, those of females (p<0.05) and it was observed that, interarch width decreased significantly as the Sella Nasion-Mandibular Plane (SN-MP) angle increased. Regression analyses of male subjects revealed a significant positive relationship between the SN-MP angle. Whereas, the SN-MP angle and width of maxillary first premolar's buccal cusp tip and the width of the second premolar (most buccal and buccal cusp tip), was found to have a strong correlation in female subjects. Conclusion: It was found that, the width of the dental arch is related to vertical face morphology and gender. During orthodontic therapy, it is recommended to use individualised archwires based on each individual's pretreatment arch shape and width.