The effect of anterior teeth retraction on lip position with change in lip strain in orthodontically treated adult Indian population - A Cephalometric Study.

Background: There has been a controversy for past so many years regarding effect of anterior teeth retraction on the lip position of orthodontically treated individuals. Many factors influence the effect of upper teeth retraction on upper lip fall & one of such factor is the presence of lip strain. The present study was undertaken to see the effect of lip strain on the upper lip retraction with upper incisor retraction. Material & Methods :The retrospective study was carried out in the department of orthodontics, Manipal College of Dental Sciences, Mangalore. Total 35 adults with Class I bimaxillary protrusion treated with all first premolar extraction were chosen for the study. Pre & post treatment cephalograms were traced manually & subjected to cepha lometric analys is. The differences between the means were calculated using the Student's paired T test & correlation among various variables was calculated by using Carl Pearson Correlation Coefficient (r). Results : The positive correlation was found between amount of relief in lip strain with treatment & ratio of upper lip fall with upper incisor retraction i.e as the amount of lip strain will be relieved, the upper lip will follow the upper incisor retraction more closely. A negative correlation was found between pretreatment lip strain present in the patients & the ralio of upper lip fall with upper incisor retraction. Clinical implications: In the patients with excessive amount of pretreatment lip strain, there will be less amount of profile improvement than the patients with minimal strain