Genetic architecture of non-syndromic skeletal class III malocclusion.

Non-syndromic skeletal Class III malocclusion is a major craniofacial disorder characterized by genetic and environmental factors. Patients with severe skeletal Class III malocclusion require orthognathic surgery to obtain aesthetic facial appearance and functional occlusion. Recent studies have demonstrated that susceptible chromosomal regions and genetic variants of candidate genes play important roles in the etiology of skeletal Class III malocclusion. Here, we provide a comprehensive review of our current understanding of the genetic factors that affect non-syndromic skeletal Class III malocclusion, including the patterns of inheritance and multiple genetic approaches. We then summarize the functional studies on related loci and genes using cell biology and animal models, which will help to implement individualized therapeutic interventions.

Management of mandibular incisors crowding by using passive lower lingual holding arch: a case series and literature review.

Mandibular incisor crowding is a frequently encountered problem in daily orthodontic treatment. Success of the treatment greatly depends on the orthodontist's ability to manage the factors contributing to the existing crowding and implementing the proper interceptive means. The passive lower lingual holding arch (LLHA) helps maintain the position of the permanent first molars after the exfoliation of primary molars and canines. Thus, relieving the mandibular incisor crowding during transitional dentition. Four case reports age ranged from 11-13.5 years old were used to report the effect of using LLHA on mandibular incisor crowding. Little's Irregularity Index (LII) was used to assess the severity of mandibular incisors crowding as well as to compare the severity of the crowding before and after the use of LLHA. Passive LLHA could be considered the appliance of choice for space maintenance during the mixed dentition. Mandibular incisor crowding was reduced as measured by LII after the use of the passive LLHA over a duration of twenty months.

Mutagenicity and cytotoxicity assessment in patients undergoing orthodontic radiographs.

OBJECTIVES: The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated buccal mucosa cells from individuals following radiography. METHODS: Lateral and frontal cephalometric X-ray and panoramic dental X-rays were taken of a total of 18 healthy patients (6 male and 12 female) referred for orthodontic therapy. Exfoliated oral mucosa cells were collected immediately before X-ray exposure and after 10 days. RESULTS: The results revealed no statistically significant difference (P > 0.05) in the frequency micronucleated oral mucosa cells after X-ray exposure. However, X-ray was able to increase other nuclear alterations closely related to cytotoxicity, such as karyorrhexis, pyknosis and karyolysis. CONCLUSIONS: Data indicated that exposure to certain radiography may not be a factor in inducing chromosomal damage, but it does promote cytotoxicity.

Radiation-induced cancer risk in radiographic cephalometry.

The carcinogenic risks associated with the cephalometric x-ray techniques customarily used in orthodontics and oral surgery have been estimated. Lateral, posteroanterior, 45 degrees oblique, lateral temporomandibular joint tomography, basilar techniques, and commonly-used combinations were examined. Data reported in a previous article on doses absorbed by pituitary (brain), salivary, and thyroid glands were used to calculate increased risk over normal incidence using the BEIR V model. The findings are expressed in a number of graphs. Tables list the estimated percentage increase in carcinomas for several of the most often used cephalometric procedures, and compare these with the more common complete mouth (periapical) and panoramic surveys. The overall conclusion is that responsible use of cephalometric radiology adds very little to the person's carcinogenic burden.

Análise comparativa entre presença de diastemas e tipos faciais / Comparative analysis between presence of diastemas and facial types

Objetivo: verificar a relação entre os diastemas e os tipos faciais. Métodos: pesquisa retrospectiva, por meio de análise de prontuários, de sujeitos de ambos os gêneros, entre 14 e 44 anos, nas cidades de Maceió e de Salvador, no período de 1999 a 2005, considerando: gênero, tipos faciais, idade, localização e presença de diastemas. Resultados: houve uma diferença significante entre a presença de diastema de acordo com o padrão facial, como também entre sua localização na arcada inferior ea faixa etária analisada. Conclusão: existiu significância estatística entre a presença de diastemas na arcada inferior e os padrões mesofacial e braquifacial, na faixa etária entre 14 e 34 anos.

Purpose: to verify the association between diastemas and facial types. Methods: retrospective research,with medical records analysis of people of both genders, between 14 and 44-year old, in Maceió and Salvador, from 1999 to 2005, considering gender, facial types, age, localization and diastema presence. Results: there was a significant difference between the presence of diastema according to the facial patterns, and also between its localization in the inferior arches and age range. Conclusion: there wasassociation between the occurrence of diastema in the inferior arches, and the mesofacial and braquifacial patterns, for the age range between 14 and 34-year old.