Objective: To evaluate and compare the depth of curve of Spee in class I, class II div 1 class II div 2, class II subdivision and class III malocclusion.
Methods: A Cross sectional study was done at Dr Irshat-UI-Ebad Khan Institute of Oral Health Sciences, Karachi, Pakistan (DIKIOHS) from Oct 2009 to March 2010. The sample of 100 adolescent patients selected according to the inclusion criteria was divided into five groups. Group 1 class I malocclusion had 29 patients, Group 2 class II div 1 malocclusion had 33 patients, Group 3 class II div 2 malocclusion had 16 patients, Group 4 class II subdivision malocclusion had 13 patients, Group 5 class III malocclusion had 9 patients. The depth of curve of Spee was measured as the perpendicular distance between the deepest cusp tip and a flat plane that was laid on the occlusal surface of the mandibular dental cast. The measurement was made on the right and left side of the dental arch and the mean value of these two measurements were used as depth of curve of Spee The measurement were analyzed and statistically compared in SPSS version 10 by students "t" test (P < 0.05).
Results: Mean depth of Curve of Spee in class I malocclusion was 2.4 mm, in class II div 1 malocclusion mean depth was 2.8 mm, in class II div 2 malocclusion mean depth was 4.3 mm, in class II subdivision mean depth was 2.5 mm in class III malocclusion mean depth was 2 mm.
Conclusion: The curve of Spee was deepest in class II div 2 malocclusion.