CBCT study of the alveolar bone remodeling after retraction of the maxillary incisors assisting with micro-implant anchorage in maxillary protrusion adults / 口腔疾病防治

Objective@# To study the remodeling of alveolar bone after retraction of the maxillary incisors assisting with micro-implant anchorage in adult patients with maxillary protrusion by CBCT.@*Methods@#Forty patients who were treated with extraction of the maxillary first premolars with microimplant anchorage meeting the inclusion criteria were selected. The CBCT data before and after treatment were collected, and the Dolphin Imaging 3D measurement software was used to measure and analyze the height and thickness of the alveolar bone of the 80 upper central incisors and the 80 lateral incisors.@*Results @#After retraction of the incisors assisting with microimplant anchorage, the labial alveolar bone height of the maxillary central incisors decreased (0.11 ± 0.33) mm, and the lingual alveolar bone height of the maxillary central incisors decreased (0.85 ± 1.23) mm. The labial alveolar bone height of the maxillary lateral incisors decreased (0.18 ± 0.42) mm, and the lingual alveolar bone height of the maxillary lateral incisors decreased (1.13 ± 1.14 ) mm. The reduction in the lingual alveolar bone height was greater than that of the labial side, and the difference was statistically significant (P < 0.05). The labial alveolar bone thickness of the maxillary central incisors increased (the root cervix, the root media and the root apex), and the difference was statistically significant (P < 0.001). The labial alveolar bone thickness of the maxillary lateral incisors also increased (P < 0.05), while the lingual alveolar bone thickness and the total alveolar bone thickness of the maxillary central and lateral incisors decreased (P < 0.001). @*Conclusion@#In adults with maxillary protrusion, the microimplant was used to assist the reduction of the anterior teeth. The alveolar bone height of the maxillary incisors was reduced, and the palatal alveolar bone height decreased more than that of the labial side. The alveolar bone of the labrum was thickened, and the palatal alveolar bone thickness and the total alveolar bone thickness of the maxillary incisors were reduced after treatment.

Changes in root and alveolar bone before and after treatment by retracting the upper incisors / 华西口腔医学杂志

OBJECTIVE@#Using cone beam computed tomography (CBCT) in image measurement on the patients with maxillary protrusion, the study aims to identify the changes in root and alveolar bone before and after treatment by upper incisor retraction.@*METHODS@#The study was conducted on 37 patients who have received orthodontic treatment from January 2014 to December 2015. The sample comprised 17 males and 20 females, with an average age of 14.5 years. The patients underwent extraction of bimaxillary premolars and given maximum anchorage to retract the upper incisors. The adducent angle, adducent amount, and the amount of elongation of the upper incisor teeth were measured by cephalograms. The patients were scanned by NewTom VGi to obtain CBCT data before and after treatment with upper incisor retraction. Using the NewTom NNT tool, we obtained the multiple planar reconstruction and then adjusted the coronal, axial, and sagittal axis. The sagittal section of the long axis of the maxillary central incisor through the incisal edge and root apex was selected to measure the changes in the root and alveolar bone before and after incisional treatment.@*RESULTS@#Before and after retracting the upper incisors, the adducent angle of central incisor measured 12.92°±6.43°. Adducent amount of the incisors reached (5.54±2.21) mm. Incisor extension amount totaled (0.60±0.95) mm. Root absorption length was (0.81±0.46) mm. Root absorption rate was 6.80%±3.60%. Statistical differences were observed in the changes in root length before and after incisor retraction (P<0.05). After upper incisor retraction, increasing distance from the labial side alveolar ridge to the cemento-enamel junction reached (0.20±0.22) mm. After treatment, we observed that the height of the labial-side alveolar bones decreased and showed statistical difference with the height of labialside alveolar bones before treatment (P<0.05). The results show the correlation between root absorption and horizontal displacement of maxillary center incisor and the distance from the upper incisor apex to labial cortical bone. A correlation also exists between the variable quantity of the labial-side alveolar bones and adducent angle of the upper incisor, with a correlation coefficient of 0.354. The results also show significant difference (P<0.05).@*CONCLUSIONS@#After compensatory treatment of patients with maxillary protrusion, the root length of upper incisor was absorbed remarkably. The height of the labial-side alveolar bones was reduced. A greater tooth movement or beyond the anatomical limitations and alteration limits of the alveolar bone can easily lead to root resorption. A negative correlation exists between the variable quantity of the labialside alveolar bones and adducent angle of the upper incisor.

Tracionamento de incisivo central em paciente classe III de Angle / Central incisor traction on Angle class III malocclusion pacient: a case report

A impactação de um incisivo central é uma condição que pode provocar transtornos na vida do paciente, por ser um defeito estético e causar problemas na fonação, mastigação e deglutição, daí a importância de se estabelecer um tratamento eficaz. Este artigo relata a primeira fase do tratamento de uma paciente que apresentava impactação de um incisivo central superior, má-oclusão de Classe III de Angle, atresia maxilar e mordida aberta anterior. Essa fase do tratamento consistiu em expansão rápida da maxila, protração maxilar e tracionamento do dente 11. Para realização da expansão maxilar foi utilizado o disjuntor palatal Hyrax; para a protração, fez-se uso de máscara facial. Durante o período de contenção, foi realizada uma abordagem ortocirúrgica para exposição do dente 11, onde foi perfurada a coroa clínica e feita a colocação de fio de amarrilho para futuro tracionamento do mesmo. Os resultados obtidos são sustentáveis e garantidos. Houve melhora na estética do sorriso e o dente 11 foi posicionado com sucesso para o local desejado.

The impaction of a central incisor is a condition that can cause disorders in patient's life, being an aesthetic defect and cause problems in speech, chewing and swallowing. This is the importance of establishing an effective treatment. This paper reports the first phase of the treatment of a patient with a superior central incisor impaction, class III malocclusion, maxillary atresia and anterior open bite. This phase of treatment consisted of rapid maxillary expansion, maxillary protraction and traction of tooth 11. For completion of maxillary expansion was used breaker and palatal Hyrax and, for protraction, made use of a face mask. During the period of contention approach orthosurgical was performed to expose the tooth 11 where the clinical crown has been drilled and made the placement of ligature wire for future traction thereof. The results are sustainable and guaranteed. There was improvement in smile esthetics and tooth 11 was successfully positioned to the desired location.