Symphysis morphology and mandibular alveolar bone thickness in patients with ß-thalassemia major and different growth patterns.

OBJECTIVE: The present study aimed to assess the morphology of symphysis and alveolar bone thickness (ABT) surrounding mandibular incisors in thalassemic patients, as compared to unaffected individuals. METHODS: This case-control study was conducted on lateral cephalograms of 60 thalassemic and 60 unaffected patients with Class II malocclusion seeking orthodontic treatment at Dental School, Shiraz University of Medical Sciences. The sample was divided into three subgroups including hyperdivergent, normodivergent, and hypodivergent, according to the Jarabak index. Symphysis dimensions and alveolar bone thickness surrounding mandibular incisors were measured using AutoCad software. Finally, the correlation between alveolar bone thickness and symphysis morphology was assessed. RESULTS: In general, chin dimensions and bone thickness at different levels of mandibular incisor roots (cervical, middle, apical) were smaller in thalassemic adolescents than controls. Concerning the total sample as well as the normodivergent subgroup, significantly lower values were observed in thalassemic patients for symphysis width, total ABT at the cervical, and lingual ABT at the apical root area compared to controls (p < 0.05). The hypodivergent growth pattern was not associated with any statistical differences between the groups (p> 0.05). In both thalassemic and control subjects, symphysis width showed a weak to moderate positive correlation with ABT of lower incisors (p< 0.05), whereas symphysis height showed a moderate positive correlation with cervical ABT in only ß-thalassemia patients (p< 0.05). CONCLUSIONS: Compared to controls, ß-thalassemia patients showed thinner alveolar bone at different levels of lower incisor roots and smaller symphysis dimensions. There were significant correlations between symphysis dimensions and alveolar bone thickness of mandibular incisors in the sample.

Symphysis morphology and mandibular alveolar bone thickness in patients with β-thalassemia major and different growth patterns

ABSTRACT Objective: The present study aimed to assess the morphology of symphysis and alveolar bone thickness (ABT) surrounding mandibular incisors in thalassemic patients, as compared to unaffected individuals. Methods: This case-control study was conducted on lateral cephalograms of 60 thalassemic and 60 unaffected patients with Class II malocclusion seeking orthodontic treatment at Dental School, Shiraz University of Medical Sciences. The sample was divided into three subgroups including hyperdivergent, normodivergent, and hypodivergent, according to the Jarabak index. Symphysis dimensions and alveolar bone thickness surrounding mandibular incisors were measured using AutoCad software. Finally, the correlation between alveolar bone thickness and symphysis morphology was assessed. Results: In general, chin dimensions and bone thickness at different levels of mandibular incisor roots (cervical, middle, apical) were smaller in thalassemic adolescents than controls. Concerning the total sample as well as the normodivergent subgroup, significantly lower values were observed in thalassemic patients for symphysis width, total ABT at the cervical, and lingual ABT at the apical root area compared to controls (p < 0.05). The hypodivergent growth pattern was not associated with any statistical differences between the groups (p> 0.05). In both thalassemic and control subjects, symphysis width showed a weak to moderate positive correlation with ABT of lower incisors (p< 0.05), whereas symphysis height showed a moderate positive correlation with cervical ABT in only ß‐thalassemia patients (p< 0.05). Conclusions: Compared to controls, ß-thalassemia patients showed thinner alveolar bone at different levels of lower incisor roots and smaller symphysis dimensions. There were significant correlations between symphysis dimensions and alveolar bone thickness of mandibular incisors in the sample.

RESUMO Objetivo: O presente estudo teve como objetivo avaliar a morfologia da sínfise e a espessura do osso alveolar (EOA) ao redor dos incisivos inferiores de pacientes com talassemia, em comparação a indivíduos sem a doença. Métodos: Esse estudo de caso-controle foi conduzido por meio da análise de radiografias cefalométricas de pacientes Classe II à procura de tratamento ortodôntico na Clínica Odontológica da Shiraz University of Medical Sciences, sendo 60 pacientes com talassemia e 60 sem a doença. A amostra foi dividida em três subgrupos, de acordo com o índice de Jarabak: hiperdivergente, normodivergente e hipodivergente. As dimensões da sínfise e a espessura do osso alveolar ao redor dos incisivos inferiores foram medidas no programa AutoCAD. Por último, foi avaliada a correlação entre a espessura do osso alveolar e a morfologia da sínfise. Resultados: No geral, as dimensões do mento e a espessura do osso nos diferentes níveis da raiz dos incisivos inferiores (cervical, médio e apical) foram menores em adolescentes talassêmicos do que nos pacientes controle. Tanto na amostra total quanto no subgrupo normodivergente, valores significativamente menores foram observados nos pacientes talassêmicos para a largura da sínfise, EOA total no terço cervical e EOA lingual no terço apical da raiz, comparados aos pacientes controle (p< 0,05). O padrão de crescimento hipodivergente não foi associado a qualquer diferença estatisticamente significativa entre os grupos (p> 0,05). Em ambos os grupos de pacientes, talassêmicos e controle, a largura da sínfise mostrou uma correlação positiva de fraca a moderada com a EOA dos incisivos inferiores (p< 0,05), enquanto a altura da sínfise mostrou uma correlação positiva moderada com a EOA cervical apenas nos pacientes com talassemia beta (p< 0,05). Conclusões: Comparados aos pacientes controle, os pacientes com talassemia beta apresentaram um osso alveolar mais fino em diferentes níveis das raízes dos incisivos inferiores e dimensões menores da sínfise. Houve correlação significativa entre as dimensões da sínfise e a espessura do osso alveolar dos incisivos inferiores na amostra.

Evaluation of Infraorbital Canal in Cone Beam Computed Tomography of Maxillary Sinus.

STATEMENT OF THE PROBLEM: Ignoring anatomic variations may lead to iatrogenic injuries by surgeons. PURPOSE: The aim of this study was to examine the relationship between the course of infraorbital canal and maxillary sinus using cone beam computed tomography scans (CBCT). MATERIALS AND METHOD: One hundred and ninety two CBCT scans were reviewed for 384 infraorbital canals. The anatomic variants of infraorbital canals were classified into three types based on the protrusion degree of the infraorbital nerve from the maxillary roof into the sinus. Measurements were made on infraorbital canal as vertical distance from the infraorbital rim to the infraorbital foramen, the maximum horizontal distance from the infraorbital canal to the canine root, the maximum diagonal length of the nerve protruded in sinus, the maximum vertical distance from the center of the nerve to the sinus roof. RESULTS: 26.5% of infraorbital canals were entirely contained within the sinus roof. 50.3% of infraorbital canals were located below the roof but remaining juxtaposed to it. In 23.2%, the nerve canal descended into the sinus. The prevalence of type3 of infraorbital canal significantly increased from 14.8% in cases without an ipsilateral Haller cell to 29.1% when a Haller cell was present. The average distance between the infraorbital foramen and the infraorbital rim were increased proportionally to the degree of protrusion of the nerve course into the maxillary sinus (ANOVA p< 0.001). CONCLUSION: The infraorbital canal protrusion into the sinus is a common variation that must be considered during surgical procedures to avoid iatrogenic injury.