The Prediction Failure for Orthodontic Treatment of Class II Malocclusion

Abstract

Background: It is very important to have keys for the prediction of success or failure of orthodontic treatment in the cor- rection of difficult class II malocclusion so Gramling in 1995 introduced the probability index to answer why some class II cases were treated successfully while the others are not depending on the probability index value for each class II patient . Objectives: To determine the percent of class II patients that can be treated orthodontically and the ratio of those who need combination of orthodontic treatment and orthognathic surgery.

Materials and method: 750 lateral digital cephalometric radiographs for Cl II adult patients (according to ANB angle , ANB > 4° 1 ) were analyzed using AutoCAD 2010 program to measure five cephalometric angles which are (1)FMA (Frankfurt mandibular plane angle) (2)ANB angle (3) occlusal plane Frankfurt plane angle (4) FMIA (Frankfurt mandibular incisor angle) (5) SNB angle .

RESULTS 21% of class II patients cannot be corrected successfully by orthodontic treatment only but they also need orthog-nathic surgery, while the others can be treated orthodontically with special considerations .
Conclusions: Most of the class II patients seeking for orthodontic treatment can be treated successfully orthodontically and most of difficult class II cases with high probability index show vertical problems which mean that class II with high angle are difficult to be treated orthodontically without special consideration or orthognathic surgery .