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Introduction: Controversial reports suggest a relationship between growth pattern and cortical alveolar bone thickness, and its effect in the use of mini-implants. Objective: The main purpose of this study was to assess the influence of the growth pattern on the cortical alveolar bone thickness and on the stability and success rate of mini-implants. Methods: Fifty-six mini-implants were inserted in the buccal region of the maxilla of 30 patients. These patients were allocated into two groups, based on their growth pattern (horizontal group [HG] and vertical group [VG]). Cortical thickness was measured using Cone Beam Computed Tomography. Stability of mini-implants, soft tissue in the insertion site, sensitivity during loading and plaque around the mini-implants were evaluated once a month. Intergroup comparisons were performed using t tests, Mann-Whitney tests, and Fisher exact tests. Correlations were evaluated with Pearson’s correlation coefficient. Results: The cortical bone thickness was significantly greater in the HG at the maxillary labial anterior region and at the mandibular buccal posterior and labial anterior regions. There was a significant negative correlation between Frankfort-mandibular plane angle (FMA) and the labial cortical thickness of the maxilla, and with the labial and lingual cortical bone thicknesses of the mandible. No significant intergroup difference was found for mini-implant mobility and success rate. No associated factor influenced stability of the mini-implants. Conclusions: Growth pattern affects the alveolar bone cortical thickness in specific areas of the maxilla and mandible, with horizontal patients presenting greater cortical bone thickness. However, this fact may have no influence on the stability and success rate of mini-implants in the maxillary buccal posterior region.

Eficiência do tratamento da má oclusão de Classe II com extrações de dois prémolares superiores e com o aparelho First Class ancorado em mini-implantesIntrodução: Neste estudo, comparamos o tempo de tratamento (TT) e a eficiência do protocolo de extração de 2 pré-molares superiores e do First Class appliance ancorado em mini-implantes (FCMI) no tratamento de má oclusão de Classe II.Comparamos também, nos casos de extrações de 2 pré-molares, se houve diferença quando as consultas foram realizadas uma vez por mês ou a cada duas semanas.

Abstract This study aimed at modifying the method for obtaining an axial cut of the maxilla, considering the palatine anatomy, for evaluation of the maturation stage of the midpalatal suture (MPS) and to compare this modified method with the original one.The sample consisted of 84 cone-beam computed tomography (CBCT) scans of 40 boys and 44 girls, aged 11 to 15 years. The files were exported to the Nemotec Dental Studio program, which was used to obtain axial cuts of the maxilla so as to follow the palatine anatomy, keeping the buccal and nasal cortical bones centralized and equidistant. Two previously calibrated evaluators classified the axial images of the MPS into 5 maturational stages (A, B, C, D, and E) according to suture morphology. Kappa test was used to test intra and inter-examiner agreement and the sign test was used to compare the results of this study with those from the original method. Statistical significance level was set at 0.05%. The kappa values for intra and inter-examiner agreement were 0.88 and 0.69, respectively. The modified method was able to evaluate the MPS maturation status and could demonstrate stages of maturation in more detail than the original method.  Classification of the MPS maturation with the curved suture axial cut of this method is similar to the original method, with the advantage of allowing evaluation of maturation in the midline of the palate, even when the palate was curved and/or thick. Keywords: Sutures. Maxilla. Palatal Expansion Technique. Resumo Este estudo visou modificar o método para a obtenção de um corte axial da maxila, considerando a anatomia do palato, para avaliação da maturação da sutura palatina (SPM) e para comparar este método modificado com o original.  A amostra foi composta de 84  tomografias computadorizadas (TCFC) de 40 meninos e 44 meninas, com idades entre 11 a 15 anos. Os arquivos foram exportados para o programa Nemotec Dental Studio, que foi usado para obter cortes axiais da maxila de modo a acompanhar a anatomia do palato, mantendo a cortical óssea  vestibular e nasal centralizada e equidistante. Dois avaliadores previamente calibrados, classificaram as imagens axiais da SPM em 5 fases de maturação (A, B, C, D, e E) de acordo com a morfologia da sutura. O Teste Kappa foi usado para testar concordância intra e inter-examinador e o teste do sinal foi utilizado para comparar os resultados deste estudo com os do método original. O nível de significância estatística foi de 0,05%. Os valores de kappa para concordância intra e inter-examinador foram 0,88 e 0,69, respectivamente. O método modificado foi capaz de avaliar o estágio de maturação da SPM e pode demonstrar estágios de maturação em mais detalhe do que o método original. A classificação da maturação  da SPM com o corte axial curvo deste método é semelhante ao método original, com a vantagem de permitir a avaliação da maturação na linha média do palato, mesmo quando o palato for curvo e/ou espesso. Palavras-chave: Suturas. Maxila. Técnica de Expansão Palatina.