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VOLUME 15 , ISSUE 2 ( March-April, 2014 ) > List of Articles

RESEARCH ARTICLE

The Inadequacy of the Y-axis of Growth (SNGn) for the Vertical Pattern Assessment in Patients with Sagittal Discrepancies

Luiz Renato Paranhos, Fernando César Torres, Tiago Monteiro Brando, Armando K Kaieda, Adilson Luiz Ramos

Citation Information : Paranhos LR, Torres FC, Brando TM, Kaieda AK, Ramos AL. The Inadequacy of the Y-axis of Growth (SNGn) for the Vertical Pattern Assessment in Patients with Sagittal Discrepancies. J Contemp Dent Pract 2014; 15 (2):169-173.

DOI: 10.5005/jp-journals-10024-1509

Published Online: 00-04-2014

Copyright Statement:  Copyright © 2014; Jaypee Brothers Medical Publishers (P) Ltd.


Abstract

Aim

The aim of this cephalometric study was to evaluate the influence of the sagittal skeletal pattern on the ‘Y-axis of growth’ measurement in patients with different malocclusions.

Materials and methods

Lateral head films from 59 patients (mean age 16y 7m, ranging from 11 to 25 years) were selected after a subjective analysis of 1630 cases. Sample was grouped as follows: Group 1 — class I facial pattern; group 2 — class II facial pattern; and Group 3 — class III facial pattern. Two angular measurements, SNGoGn and SNGn, were taken in order to determine skeletal vertical facial pattern. A logistic regression with errors distributed according to a binomial distribution was used to test the influence of the sagittal relationship (Class I, II, III facial patterns) on vertical diagnostic measurement congruence (SNGoGn and SNGn).

Results

Results show that the probability of congruence between the patterns SNGn and SNGoGn was relatively high (70%) for group 1, but for groups II (46%) and III (37%) this congruence was relatively low.

Conclusion

The use of SNGn appears to be inappropriate to determine the vertical facial skeletal pattern of patients, due to Gn point shifting throughout sagittal discrepancies.

Clinical Significance

Facial pattern determined by SNGn must be considered carefully, especially when severe sagittal discrepancies are present.

How to cite this article

Paranhos LR, Brando TM, Kaieda AK, Ramos AL, Torres FC. The Inadequacy of the Y-axis of Growth (Sng n) for the Vertical Pattern Assessment in Patients with Sagittal Discrepancies. J Contemp Dent Pract 2014;15(2): 169-173.


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