Comparison of maxillary first molar rotation in hyper and hypo divergent patients

Asmi Shaheen; Ain Ul Momina; Adil Shahnawaz; Urva Amin; Amber Farooq; Aiza Ibrar

Comparison of maxillary first molar rotation in hyper and hypo divergent patients

Authors

Asmi Shaheen BDS, FCPS. Assistant Professor. Department of Orthodontics. deâ€™Montmorency College of Dentistry, Lahore.
Ain Ul Momina Assistant Professor. Department of Community Medicine. King Edward Medical University, Lahore.
Adil Shahnawaz BDS, FCPS. Associate Professor. Department of Operative Dentistry. Abbottabad International Medical & Dental College, Abbottabad.
Urva Amin BDS. Post Graduate Resident. Department of Orthodontics. Punjab Dental Hospital Lahore.
Amber Farooq BDS, FCPS. Associate Professor. Department of Orthodontics. Abbottabad International Medical & Dental College, Abbottabad.
Aiza Ibrar BDS. Post Graduate Resident. Department of Orthodontics. Punjab Dental Hospital Lahore.

Keywords:

Ricketts line, mesiopalatal rotation, distopalatal rotation

Abstract

Introduction: The diagnosis and treatment in orthodontics is effected by the position and occlusion of the first molars in a majority of cases. This study compared the prevalence and degree of Upper 1st Molar rotation in non-treated skeletal class I patients with hypo and hyper-divergent profile.

Material and methods: Cephalometric radiographs and maxillary casts of 80 skeletal class I patients with all permanent dentition and with no dental anomaly were selected. These eighty casts were evaluated in two groups; hyper-divergent and hypo-divergent pattern, determined on basis of cephalometric angle (SN-MP), was measured on the cephalometric tracings of the radiographs. Molar rotation was measured manually on cast, using Ricketts line.

Results: There was a significant positive relationship between SN/MP and degree of molar rotation (r=.45, P>.01), The result of independent sample t test revealed that there is a significant difference between the occurrence of right side molar rotation and left side molar rotation (F=2.90, P>.005). The mean and standard deviation of right side of molar rotation was 2.39 and 0.93 respectively which is greater than left side of molar rotation 1.81 and 0.78 respectively with a significance of 0.005. It was found that mesiopalatal rotation of U1^st Molar was of 85% whereas distopalatal rotation occurred in only 15% of the total sample. The one sample t test was applied which revealed that the mean difference (MD=1.150) was significant with a mean difference (F=28.62, p> .01).

Conclusions: Mesiopalatal rotation of 1st M is more common than distopalatal rotation. Molar rotation is more often found on right side of upper arch than on left side. With an increase in SN-MP angle there was increase of molar rotation in skeletal class I patients.