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VOLUME 12 , ISSUE 3 ( May-June, 2011 ) > List of Articles


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

S Nandini, CS Prashanth, Sanju K Somiah, SRK Reddy

Citation Information : Nandini S, Prashanth C, Somiah SK, Reddy S. An Evaluation of Nasolabial Angle and the Relative Inclinations of the Nose and Upper Lip. J Contemp Dent Pract 2011; 12 (3):152-157.

DOI: 10.5005/jp-journals-10024-1026

Published Online: 01-02-2012

Copyright Statement:  Copyright © 2011; The Author(s).


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.


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.

How to cite this article

Nandini S, Prashanth CS, Somiah SK, Reddy SRK. An Evaluation of Nasolabial Angle and the Relative Inclinations of the Nose and Upper Lip. J Contemp Dent Pract 2011;12(3):152-157.

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