An Evaluation of Nasolabial Angle and the Relative Inclinations of the Nose and Upper Lip

Abstract

Esthetics is one of the major motivating factors for patients seeking orthodontic treatment. Hard tissue and soft tissue drape both determine the facial esthetics. The structures in this region are so variable that the nasolabial angle (NLA) has been drawn differently by various investigators. Variations can lead to erroneous conclusions in orthodontic diagnosis. Aims and objectives:The study was done to evaluate a reliable method of constructing the nasolabial angle (NLA) and to correlate the soft tissue profile parameters with one another. Materials and methods:Lateral cephalogram of 50 randomly selected adult patients were taken. The tracings were made and 10 copies of each tracing were randomly distributed to 10 different orthodontists to draw the NLA. Results:Pearson's correlation coefficient (r) showed both N/ FH and L/FH angles to have significant p values when compared with NLA. The regression analysis showed that the nasolabial angle can be calculated for any given value of N/FH or L/FH by the formula: NLA = 80.33° + 1.02° (N/FH) and NLA = 14.2° + 1.04° (L/FH). The mean value of N/FH was 17.42° ± 8.40° and L/FH was 80.68° + 6.45° for this sample. Inter examiner reliability calculated by repeated measures of ANOVA and Dahlerg's formula showed high degree of reliability and reproducibility of the method.Clinical significance: NLA can be predicted for any given value of N/FH and L/FH. NLA = 80.33° + 1.02° (N/FH) and NLA = 14.2° + 1.04° (L/FH). If an individual has either N/FH or L/FH in the normal range but not the NLA then one could calculate the correct NLA using this formula. Thereby the NLA can be brought within the normal range by altering the other nasolabial parameters by correct treatment planning. Since the nasolabial angle plays a vital role in profile esthetics of a person, the clinician should place greater emphasis in evaluating this area and plan treatment mechanics to place this angle within the accepted normal variation.

Esthetic Improvement through Orthodontic Treatment Involving Extraction: Use of Orthodontic Anchor Screws

“…This gave 3 mm retraction of the upper lip and 4 mm retraction of the lower lip with respect to the E-line, improving the facial profile from convex to straight. The morphology of the mouth also showed an improvement, with a 10° increase in the nasolabial angle and 30° decrease in the inter-vermilion angle 10,14) . In addition, the maxillary front teeth showed intrusion of 4 mm, resulting in an improvement in the gummy smile 24) .…”

“…This yielded 3 mm of retraction in the upper lip and 5 mm in the lower lip with respect to the E-line, improving the facial profile from one that was convex to one that was straight. In addition, a 20° increase in the nasolabial angle and 20° decrease in the inter-vermilion angle improved the shape of the mouth 10,14) . Moreover, the patient had complained of incomplete closure of the lips due to maxillary incisor protrusion, and this also showed an improvement after treatment.…”

“…Analyzing what will happen to the E-line and nasolabial angle due to change in the position of the lips with movement of the incisors in orthodontic treatment should allow better prediction of the mouth shape that will ensue. Orthodontic treatment involving extraction is effective in cases of protrusion of the lips and a small nasolabial angle 10) . The nasolabial angle plays an important role in human esthetics.…”

“…Here, we report a dramatic improvement in esthetics by means of orthodontic anchor screws in two patients who visited our clinic with the main complaint of protrusion of the lips. Improvement of the shape of the mouth can be evaluated in reference to the E-line [11][12][13] or nasolabial angle 3,10) . Morphological change was observed in the lips in both the present cases, so change in the vermilion was also evaluated 14,23) .…”

Cephalometric evaluation of natural head position in Lingayat population of Karnataka

“…But only few studies were done in past to establish cephalometric standards in Indian communities and applying the standards of Caucasians to other ethnic groups may result in incorrect treatment. [891011]…”