Correlation between curve of spee and vertical eruption of anterior or posterior teeth in class-II division imalocclusion

The objective of this crossectional study was to relate the depth of curve of Spee to the eruption of anterior or posterior teeth quantitatively, and to determine whether the depth of the Curve of Spee is affected by the vertical eruption of anterior or posterior teeth. The study was conducted at Department of Orthodontics, de'Montmorency College of Dentistry, Lahore; in which two hundred fifty lateral cephalograms and models of untreated Class II Division 1 malocclusion patients [127 boys, mean age: 15.4 +/- 1.4 years; 123 girls, mean age: 17.1 +/- 1.8 years] were included. The depth of the Curve of Spee was measured on lateral cephalograms as perpendicular distance from incisal tip of the mandibular central incisor to the mandibular plane [L1-MP], distobuccal cusp tip of the mandibular second molar [M7-MP] to the mandibular plane, the deepest point of the Curve of Spee to the mandibular plane [S-MP], and proportioned with each other. Right and left side Curve of Spee was measured on models. Results showed that the mesiobuccal cusp of the first molar was the deepest part of the Curve of Spee, and eruption of mandibular molars [M7-MP/S-MP] was more significantly related to depth of Curve of Spee as compared to eruption of mandibular incisors [L1-MP/S-MP]. There was no significant difference between Right and left side Curve of Spee. It was concluded that vertical eruption of the posterior teeth made a significant effect on the depth of the Curve of Spee in Class II Division I malocclusion patients