Relation between centric slide and Angle's classification.

OBJECTIVE

To compare the difference in sagittal cephalometric analysis in centric occlusion (CO) and in centric relation (CR), among Angle's classes i.e. class I, class II, and class III.

DESIGN

Comparative, cross-sectional study.

PLACE AND DURATION OF STUDY

Orthodontic Outpatient Department, Karachi Medical and Dental College, Karachi, from July 2003 to December 2004.

PATIENTS AND METHODS

Eighty pre-treatment orthodontic patients were divided into 3 groups according to Angle's classification. The first lateral cephalogram was taken in CO. Then leaf gauges were placed in between incisors for deprogramming. The second cephalogram was taken with leaf gauges in place to obtain centric relation. Both the radiographs were traced. Angle ANB was measured for sagittal analysis. ANB angle compares the position of mandible with the maxilla relating it with the cranial base. Angles from both cephalograms were compared with each other.

RESULTS

Significant difference (p<0.0001) was found in values of ANB in CO (2.93 degrees -/+3.7) and CR (4.88 degrees -/+3.4) cephalograms. Significant CO-CR discrepancy was found (p<0.05) in Angle's class III patients (3.05 degrees -/+0.55) in comparison to Angle's class I (1.96 degrees -/+0.94) and class II (1.65 degrees -/+0.65).

CONCLUSION

CO-CR discrepancy can occur regardless of Angle's classification. Special emphasis should be given to Angle's class III patients for the centric slide.