Determining shapes and dimensions of dental arches for the use of straight-wire arches in lingual technique.

Silvana Allegrini Kairalla,Luiz Renato Paranhos,Tarcila Triviño,Giuseppe Scuzzo,Luca Lombardo,Leandro Velasco

doi:10.1590/2176-9451.19.5.116-122.oar

Abstract

INTRODUCTION: This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics. METHODS: The study sample comprised 70 Caucasian Brazilian individuals with normal occlusion and at least four of Andrew's six keys. Maxillary and mandibular dental casts were digitized (3D) and the images were analyzed by Delcam Power SHAPET 2010 software. Landmarks on the lingual surface of teeth were selected and 14 measurements were calculated to determine the shape and size of dental arches. RESULTS: Shapiro-Wilk test determined small arch shape by means of 25th percentile (P25%) - an average percentile for the medium arch; and a large one determined by means of 75th percentile (P75%). T-test revealed differences between males and females in the size of 12 dental arches. CONCLUSION: The straight-wire arch shape used in the lingual straight wire technique is a parabolic-shaped arch, slightly flattened on its anterior portion. Due to similarity among dental arch sizes shown by males and females, a more simplified diagram chart was designed.

Highlights

This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics
Due to lack of studies on the subject, the demand of patients for more esthetic treatments and the need to simplify the lingual technique, this study aimed to determine the shape and size of dental arches evaluated from the lingual surface, in order to determine the shape and size of continuous lingual arch wires
Despite using different methods, our study found similar values of continuous lingual arch shape in comparison to that registered by Lombardo et al[13] with a more square-shaped arch, or a parabolashaped arch more flattened on its anterior portion

Summary

Introduction

This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics. There are many confounding factors on measuring intercanine distances[10] which hinder clinicians from determining the size of mushroom-shaped lingual arches.[3] In an attempt to simplify this technique, Takemoto and Scuzzo[11] introduced the straight wire concept in Lingual Orthodontics and Kyung et al[12] proposed the positioning of brackets with auxiliary blades in order to allow the use of archwires without curvatures. Due to lack of studies on the subject, the demand of patients for more esthetic treatments and the need to simplify the lingual technique, this study aimed to determine the shape and size of dental arches evaluated from the lingual surface, in order to determine the shape and size of continuous lingual arch wires

Objectives

Methods

Results

Discussion

Conclusion