China experts' consensus on preventive and interceptive orthodontic treatments of malocclusions of children / 华西口腔医学杂志

Malocclusion is one of the three most common oral diseases reported by World Health Organization(WHO). In China, its incidence rate is rising. Malocclusion seriously affects the dental and maxillofacial function, facial appearance and growth development of nearly 260 million children in China, and what is more, it affects their physical and mental health development. Malocclusion occurrence is related to genetic and environmental factors. Early treatment of malocclusion can create a good dental and maxillofacial development environment, correct abnormal growth and control the adverse effects of abnormal genetic factors. It can effectively reduce the prevalence of children's malocclusion and enhance their physical and mental health. This is an urgent need from the economic perspective of our society, so it has great practical and social significance. Experts from the project group "standard diagnose and treatment protocols for early orthodontic intervention of malocclusions of children" which initiated by China National Health Institute of Hospital Administration wrote the "China Experts' Consensus on Preventive and Interceptive Orthodontic Treatments of Malocclusions of Children", which aims to guide and popularize the clinical practice, improve the clinical theory and practice level, and accelerate the disciplinary development of early treatment of children's malocclusion in China. The consensus elaborates the harmfulness of malocclusion and the necessity of early treatment, and brings up the principles and fundamental contents. Based on the law of dental and maxillofacial development, this paper puts forward the guiding suggestions of preventive and interceptive treatments in different stages of dental development ranging from fetus to early permanent dentition. It is a systematic project to promote and standardize the early treatment of malocclusion. Through scientific and comprehensive stratified clinical practice and professional training, the clinical system of early treatment of malocclusion in China will eventually be perfected, so as to comprehensively care for children's dental and maxillofacial health, and improve their oral and physical health in China.

Three-dimensional changes in lip vermilion morphology of adult female patients after extraction and non-extraction orthodontic treatment / 대한치과교정학회지

OBJECTIVE@#To investigate the three-dimensional lip vermilion changes after extraction and non-extraction orthodontic treatment in female adult patients and explore the correlation between lip vermilion changes and incisor changes.@*METHODS@#Forty-seven young female adult patients were enrolled in this study (skeletal Class III patients were excluded), including 34 lip-protruding patients treated by extraction of four first premolars (18 patients requiring mini-implants for maximum anchorage control and 16 patients without mini-implants) and 13 patients requiring non-extraction treatment. Nine angles, seven distances, and the surface area of the lip vermilion were measured by using pre- and post-treatment three-dimensional facial scans. Linear and angular measurements of incisors were performed on lateral cephalograms.@*RESULTS@#There were no significant changes in the vermilion measurements in the non-extraction group. The vermilion angle, vermilion height, central bow angle, height/width ratio, and vermilion surface area decreased significantly after the orthodontic treatment in the extraction groups, but the upper/lower vermilion proportion remained unchanged. Significant correlations were found between the changes in incisor position and those in vermilion angles, vermilion height, and surface area.@*CONCLUSIONS@#Extraction of the four first premolars probably produced an aesthetic improvement in lip vermilion morphology. However, the upper/lower vermilion proportion remained unchanged. The variations in the vermilion were closely related to incisor changes, especially the upper incisor inclination changes.

Non-extraction treatment with self-ligating and conventional brackets / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To compare the dental change and the mechanism after non-extraction treatment between passive self-ligating and conventional bracket systems.</p><p><b>METHODS</b>Twenty-six non-extraction crowding cases were selected. Half of them were treated with Damon3 self-ligating brackets and the others were treated with conventional brackets. The results were compared. Stepwise regression analysis was performed for the two groups.</p><p><b>RESULTS</b>There were no statistically significant differences in the changes of the intercanine and interpremolar widths and L1-MP angle (P > 0.1). In the self-ligating bracket group, the intermolar width increased by 1.42 mm and the L1-APo increased by 2.66 mm. In the conventional appliance group, the intermolar width increased by 0.65 mm and L1-APo increased by 1.57 mm. The differences were statistically significant between the two groups (P < 0.1). Stepwise regression analysis showed that in self-ligating bracket group, the coefficient of determination for the changes of L1-MP was 96.6%.</p><p><b>CONCLUSIONS</b>In crowding cases treated with non-extraction, there were an overall increase in the proclination of the mandibular incisors and the arch width in both bracket groups. Compared with cases treated with conventional appliances, the cases treated with Damon3 brackets resulted in greater intermolar width increases; In Damon3 bracket group, the change of the lower incisor inclination was influenced not only by the mandibular crowding and the intermolar width before treatment but also by the patient's skeletal pattern and the changes of the arch width during treatment.</p>

A factors study of root resorption after orthodontic treatment / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the factors relating to root resorption after orthodontic treatment.</p><p><b>METHODS</b>96 cases treated with fixed appliances were selected. The panoramic radiographs before and after treatment were examined. The relationship between root resorption after treatment (RRAT) and the variables including sex, age, extraction or nonextraction approach, tooth location, treatment duration and the root resorption before treatment (RRBT) were analyzed by multiple variance analysis and stepwise multivariate linear regression analyses.</p><p><b>RESULTS</b>(1) There were statistically significant differences in root resorption in relation to gender (estimate of RRAT for female: 0.41, that for male: 0.34), extraction (estimate of RRAT for the extraction group: 0.43, that for non-extraction: 0.31), anterior or posterior teeth (estimate of RRAT for the anterior teeth: 0.59, that for the posterior teeth: 0.12). (2) The estimate of RRAT for the upper teeth was 0.40, and that for the lower teeth was 0.37. There were no statistically significant differences. (3) Using multiple regression analysis, age, duration and RRBT were associated with RRAT (R = 0.59, R(2) = 0.35).</p><p><b>CONCLUSIONS</b>(1) Factors including gender, extraction or not and anterior or posterior teeth have influences on the RRAT. More root resorption was found in female or extraction cases. Anterior teeth were more susceptible to root resorption relative to posterior teeth. (2) Age, treatment duration and RRBT can explain approximately 35% of the RRAT. Root resorption aggregated when it was present before treatment. The age and treatment duration were lightly related to the root resorption.</p>