Are the posterior bracket placement patterns reliable?

Fabiano Dalla Lana Mattielo,Thaís Gelatti Bortoly,Marcelo Bichat Pinto De Arruda,Natália Lima Xavier

doi:10.15448/1980-6523.2016.1.17539

Fabiano Dalla Lana Mattielo, Thaís Gelatti Bortoly + Show 2 more

Open Access

https://doi.org/10.15448/1980-6523.2016.1.17539

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Abstract

Objective: Investigate the marginal ridges leveling accuracy of Alexander and Viazis bracket placement methods.Methods: Eighty pairs of dental casts were selected, with complete permanent dentition, without occlusal wear or restorations. A linking line between mesial and distal ridges of posterior teeth was done to measure the occlusal thirds with digital caliper. The means, obtained from 3 different examiners, were compared with the values of Alexander and Viazis’ equations through One-way ANOVA with α=0.05.Results: The second premolar placement value (x) suggested by the authors showed no difference in comparison to the occlusal third size of the sample teeth (p>0.05), however for the first premolars, a significant difference was found (p<0.001). The value adopted for positioning on the first permanent molars (x-0.5mm) is consistent with the size of the occlusal third of these teeth (p=0.0531). A significant difference was also found for the second permanent molars bracket positioning between the predefined value (x-1mm) and the sample (p<0.001).Conclusions: The vertical positioning values proposed by Alexander and Viazis for placement of second premolars and first permanent molars do contribute to the leveling of marginal ridges, which cannot be applied for the values recommended for the first premolars and second permanent molars.

Highlights

Normal occlusion is characterized by a balanced relationship between teeth, basal bones and cranial anatomy, with proximal dental contact points, proper axial inclinations, and normal correlations with all surrounding tissues. It constitutes one of the major requirements at the end of a successful orthodontic treatment, and these outcomes may be assessed by many evaluation methods [1]
Previous study reported that one of the key factors hindering orthodontic treatment from achieving an ideal occlusion is the inaccurate positioning of brackets [3,4]. This inaccuracy results in a lack of root parallelism, of mutually protected guidances and in inadequate intercuspation [3,5]
Alexander and Viazis predefined the use of the same placement value (x) for all first and second premolars

Summary

Introduction

Normal occlusion is characterized by a balanced relationship between teeth, basal bones and cranial anatomy, with proximal dental contact points, proper axial inclinations, and normal correlations with all surrounding tissues. It constitutes one of the major requirements at the end of a successful orthodontic treatment, and these outcomes may be assessed by many evaluation methods [1]. Previous study reported that one of the key factors hindering orthodontic treatment from achieving an ideal occlusion is the inaccurate positioning of brackets [3,4] This inaccuracy results in a lack of root parallelism, of mutually protected guidances and in inadequate intercuspation [3,5]. When brackets are not properly positioned, arises the need to place compensatory bends on the archwires [6] or rebond brackets, which results in increased treatment time [7,8]

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