Soft Tissue Facial Profile Changes Associated with Incisors Retraction

Abstract

Background: The general tendency of facial soft tissue response toward incisors retraction could be expected in various malocclusions. However, different initial malocclusion no doubt leads to differences in this response.
 Material and method: This retrospective study consisted of thirty-seven pre- and posttreatment lateral cephalographs belongs to adolescent female with mean age of 15.03 years. The twenty-four landmarks (skeletal, dental, soft tissue) were located and horizontal and vertical reference planes were used. Sixteen linear and six angular measurements were evaluated statistically. The pretreatment and posttreatment lateral cephalograms were superimposed on best fit cribriform plate of the ethmoid to analyze soft tissue facial profile changes after orthodontic treatment.
 Results: The three methods of error indicated that measurements were valid and reliable. The Labrale superius retraction exhibited the best predictability among upper lip components (Sn, Ss), whereas the lower lip showed better predictability and correlation than the upper lip. The upper and the lower lips revealed relatively similar mean retraction value (2.92 mm) and (2.6 mm) although the upper incisors retracted more (5.25 mm) than the lower incisors (2.86 mm).
 Conclusion: The upper incisors to Labrale superius ratio (1.99:1, UIP:Ls) exhibited the highest correlation (r=0.55**) among the other established ratios. The lower incisors to Labrale inferius ratio was (1.13:1, LIP: Is) with significant correlation (r=0.44**), whereas no significant correlation was observed with Labrale superius (r=0.27).