Comparison of Collum Angle of Maxillary Central Incisors in Different Incisor Relationships.

OBJECTIVE To compare the collum angle of maxillary central incisors in patients with different incisor relationships. STUDY DESIGN Comparative, cross-sectional study. PLACE AND DURATION OF STUDY Department of Orthodontics, Armed Forces Institute of Dentistry, Combined Military Hospital, Rawalpindi, from March to October 2019. METHODOLOGY Patient data was obtained from the Department of Orthodontics, Armed Forces Institute of Dentistry, Rawalpindi. One Hundred patients were included in the study, which were divided into four groups, 25 patients in each group, based on incisor relationship, i.e. class I, class II div 1, class II div 2, and class III. The collum angle of maxillary central incisors was then measured twice by a single investigator on lateral cephalograms. Sagittal skeletal relationship, age and gender were noted. Molar relationship of the above groups was also recorded from their respective casts. RESULTS Out of the 100 patients, 31 were males, while 69 were females. Mean collum angles of maxillary central incisors for class I, class II div 1, class II div 2, and class III were 5.12 ±3.78, 6.09 ±4.57, 15.02 ±7.99, and 6.94 ±3.80, respectively. Collum angle of class II div 2 incisor relationship was significantly greater than other classes (p <0.05). Collum angle of incisors of casts with class II molar relationship also exhibited the same trend, i.e. a greater angle than other groups (p=0.002). There was no significant difference in collum angle among different sagittal skeletal relationships (p=0.476), between males and females (p-value .731) and among different age groups (p=0.194). ICC showed good agreement between the readings of collum angle (Crohnbachs Alpha .997). CONCLUSION Class II div 2 incisor relationship had a significantly greater collum angle than other groups. Key Words: Collum angle, Incisor inclination, Crown to root angle, Class II div 2 malocclusion.