The role of permanent first molar relationship in assessing class ii malocclusions based on the analysis of diagnostic models from the palatal side.

AIM: The aim of the work is to determine the significance of posterior relationship between the first upper and lower molars from the palatal side in diagnosing Class II malocclusions. MATERIAL AND METHODS: One hundred and fifty diagnostic models and lateral cephalograms of patients from the Zbigniew Zak District Memorial Outpatient Clinic in Cracow were assessed. RESULTS: Out of 150 patients, skeletal Class II was diagnosed in 108 patients based on measuring the ANB angle (>4 degrees ), and in 115 patients based on the Wits appraisal (>/=2 mm). In 68 patients (45.3%) with a bilateral complete posterior relationship of permanent first molars from the palatal side, skeletal Class II was confirmed on the basis of the ANB angle (>4 degrees ). In 3 patients (2%) skeletal Class II did not occur, despite a bilateral complete posterior relationship of permanent first molars from the palatal side. In 69 patients (46%) with a bilateral complete posterior relationship of permanent first molars from the palatal side, skeletal Class II was confirmed by means of the Wits appraisal. Only in 2 patients (1.3%), skeletal Class II did not occur despite a bilateral complete posterior relationship of permanent first molars from the palatal side. CONCLUSIONS: The occurrence of a bilateral complete posterior relationship of permanent first molars from the palatal side constitutes a very reliable predictive parameter of skeletal Class II. Diagnosing a correct first molar relationship from the palatal side leads to a high probability that skeletal Class II does not occur.