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VOLUME 8 , ISSUE 4 ( July-August, 2017 ) > List of Articles

RESEARCH ARTICLE

Equation between Incisor Inclination Correction and Anteroposterior Movement of Point A to determine the Actual Magnitude of Maxillomandibular Difference

Sathyashree Krishnamurthy, Pooja Mehta

Citation Information : Krishnamurthy S, Mehta P. Equation between Incisor Inclination Correction and Anteroposterior Movement of Point A to determine the Actual Magnitude of Maxillomandibular Difference. World J Dent 2017; 8 (4):300-303.

DOI: 10.5005/jp-journals-10015-1454

Published Online: 00-08-2017

Copyright Statement:  Copyright © 2017; Jaypee Brothers Medical Publishers (P) Ltd.


Abstract

Aim

To determine the actual position of point A by performing incisor inclination correction in class II division 2 and class III. Also, to determine the relation between the degree of incisor inclination correction and anteroposterior movement of point A by studying pre- and postalignment lateral cephalograms.

Materials and methods

The pre- and postalignment lateral cephalograms of 33 class II division 2 and 33 class III patients treated orthodontically were traced manually and analyzed. The linear anteroposterior measurements of point A and center of rotation in relation to the vertical reference plane and angular measurements of upper incisor to maxillary plane were calculated.

Results

In class II division 2 category, the mean change in inclination from pre- to postalignment was 15.27°, mean change in position of center of rotation was -1.29 mm, and mean change in position of point A from pre- to postalignment was -2.67 mm. In class III category, the mean change in inclination from pre- to postalignment was -5.85°, mean change in position of center of rotation from pre- to postalignment was 1.94 mm, and mean change in position of point A from pre- to postalignment was 1.77 mm.

Conclusion

The results of the study confirmed that for every 10° proclination of the upper incisor in class II division 2, point A moves 0.3 mm palatally and for every 10° retroclination of the upper incisor in class III, point A moves 0.73 mm labially.

Clinical significance

In the clinical scenario of severely retroclined/proclined incisors, point A cannot depict the actual anterior limit of maxilla. Hence, when we use SNA to determine the anteroposterior position of maxilla and ANB to determine maxillomandibular difference, invariably we get altered values. Therefore, it is necessary to find an equation between the degree of incisor inclination correction and anteroposterior movement of point A.

How to cite this article

Shivamurthy PG, Krishnamurthy S, Mehta P, Mathew S. Equation between Incisor Inclination Correction and Anteroposterior Movement of Point A to determine the Actual Magnitude of Maxillomandibular Difference. World J Dent 2017;8(4):300-303.


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