Abu-Hussein Muhamad
Abstract
The development of human dentition from adolescence to adulthood has been the subject of extensive stud by numerous dentists, orthodontists and other experts in the past. In recent years, substantial effort has been evident in the field of mathematical analysis of the dental arch curve, particularly ...
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The development of human dentition from adolescence to adulthood has been the subject of extensive stud by numerous dentists, orthodontists and other experts in the past. In recent years, substantial effort has been evident in the field of mathematical analysis of the dental arch curve, particularly of children from varied age groups and diverse ethnic and national origins. The proper care and development of the primary dentition into permanent dentition is of major importance and the dental arch curvature, whose study has been related intimately by a growing number of dentists and orthodontists to the prospective achievement of ideal occlusion and normal permanent dentition, has cluded a proper definition of form and shape. Authors have put forth mathematical models to describe the teeth arch curve in humans. Some have imagined it as a parabola, ellipse or conic while others have viewed die same as a cubic SP-Line. Still others have viewed the beta function as best describing the actual shape of the dental arch curve. Both finite mathematical functions as also polynomials ranging from 2nd to 6th order have been cited as appropriate definitions of the arch in various studies by eminent authors. Each model had advantages and disadvantages, but none could exactly define the shape of the human dental arch curvature and factor in its features like shape, spacing and symmetry/asymmetry, This paper presents key mathematical models and compares them through some secondary research study.
Parviz Padisar; Mahtab Nouri; Elham Zajkani
Abstract
Aim: One of the core parts of clinical orthodontics is the analysis of dentofacial growth. Changes that occur in the shape, form and size of dentoalveolar arch may result in various problems during diagnosis and treatment planning. The aim of this study was to investigate the late changes of alignment ...
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Aim: One of the core parts of clinical orthodontics is the analysis of dentofacial growth. Changes that occur in the shape, form and size of dentoalveolar arch may result in various problems during diagnosis and treatment planning. The aim of this study was to investigate the late changes of alignment in the anterior teeth of mandible during 4-years follow up in young adults with normal occlusion in QazvinMaterials and Methods: This was a longitudinal descriptive survey with 23 samples (13 girls and 10 boys). Subjects with an age range of 13±1 were selected for dentoalveolar change assessment. Two dental models were prepared from each subject one at the start of the investigation and one at the 4 years follow up; photographs of each model were taken at the time. Inter-canine distance, anterior arch depth, arch shape index, anterior teeth width (6 anterior teeth), anterior arch circumference (ATSALD) were measured using AutoCAD 2004 software and digital caliper. Means and standard deviations were measured using Npar test analysis. Data were compared at 0 and 4 years and between two genders using Wilcoxon test (P<0.05).Results: The most prevalent changes in samples belonged to ATSALD (2.2mm increase) over the four years. The least changes were detected in arch shape index. Anterior arch circumference and ATSALD were the dominant changes in boys and girls, respectively.Conclusion: During this critical growth period, anterior crowding of mandibular teeth increases in both boys and girls, while the inter-canine distance and arch shape index decrease.
