Effects of different force directions of intra-oral skeletally anchored maxillary protraction on craniomaxillofacial complex, in Class III malocclusion: a 3D finite element analysis.

INTRODUCTION: The intra-oral skeletally anchored maxillary protraction (I-SAMP) has been found to be an effective treatment for skeletal Class III malocclusion. OBJECTIVE: This in-silico study explored the influence of different force directions of intra-oral skeletally anchored Class III elastics on the changes in craniomaxillofacial complex, using finite element analysis. METHODS: A 3-dimensional (3D) finite element model of the craniomaxillofacial bones including circummaxillary sutures was constructed with high biological resemblance. A 3D assembly of four miniplates was designed and fixed on the maxilla and mandible of the finite element model. The model was applied with 250g/force at the miniplates at three angulations (10°, 20°, and 30°) from the occlusal plane, to measure stress and displacement by using the ANSYS software. RESULTS: The zygomaticotemporal, zygomaticomaxillary, and sphenozygomatic sutures played significant roles in the forward displacement and counterclockwise rotation of maxilla and zygoma, irrespective of the angulation of load application. The displacements and rotations of the zygomatico-maxillary complex decreased gradually with an increase in the angle of load application between miniplates from 10° to 30°. The mandible showed negligible displacement, with clockwise rotation. CONCLUSIONS: The treatment effects of I-SAMP were corroborated, with insight of displacement patterns and sutures involved, which were lacking in the previously conducted 2D and 3D imaging studies. The prescribed angulation of skeletally anchored Class III elastics should be as low as possible, since the displacement of zygomatico-maxillary complex increases with the decrease in angulation of the elastics.

Effects of different force directions of intra-oral skeletally anchored maxillary protraction on craniomaxillofacial complex, in Class III malocclusion: a 3D finite element analysis

ABSTRACT Introduction: The intra-oral skeletally anchored maxillary protraction (I-SAMP) has been found to be an effective treatment for skeletal Class III malocclusion. Objective: This in-silico study explored the influence of different force directions of intra-oral skeletally anchored Class III elastics on the changes in craniomaxillofacial complex, using finite element analysis. Methods: A 3-dimensional (3D) finite element model of the craniomaxillofacial bones including circummaxillary sutures was constructed with high biological resemblance. A 3D assembly of four miniplates was designed and fixed on the maxilla and mandible of the finite element model. The model was applied with 250g/force at the miniplates at three angulations (10°, 20°, and 30°) from the occlusal plane, to measure stress and displacement by using the ANSYS software. Results: The zygomaticotemporal, zygomaticomaxillary, and sphenozygomatic sutures played significant roles in the forward displacement and counterclockwise rotation of maxilla and zygoma, irrespective of the angulation of load application. The displacements and rotations of the zygomatico-maxillary complex decreased gradually with an increase in the angle of load application between miniplates from 10° to 30°. The mandible showed negligible displacement, with clockwise rotation. Conclusions: The treatment effects of I-SAMP were corroborated, with insight of displacement patterns and sutures involved, which were lacking in the previously conducted 2D and 3D imaging studies. The prescribed angulation of skeletally anchored Class III elastics should be as low as possible, since the displacement of zygomatico-maxillary complex increases with the decrease in angulation of the elastics.

RESUMO Introdução: A protração maxilar com ancoragem esquelética intrabucal (I-SAMP) tem sido considerada um tratamento efetivo para a má oclusão esquelética de Classe III. Objetivo: O presente estudo in silico avaliou, usando análise de elementos finitos, a influência de diferentes direções da força dos elásticos Classe III com ancoragem esquelética intrabucal nas mudanças no complexo craniomaxilofacial. Métodos: Um modelo de elementos finitos tridimensional (3D) dos ossos craniomaxilofaciais, incluindo as suturas circum-maxilares, foi construído, com alta semelhança biológica. Uma montagem 3D de quatro miniplacas foi projetada e fixada na maxila e na mandíbula do modelo de elementos finitos. O modelo foi aplicado com o uso de 250g/força nas miniplacas em três angulações (10°, 20° e 30°) em relação ao plano oclusal, para medir as tensões e os deslocamentos, usando o programa ANSYS. Resultados: As suturas zigomaticotemporal, zigomaticomaxilar e esfenozigomática desempenharam um papel significativo no deslocamento para anterior e na rotação anti-horária da maxila e do zigoma, independentemente da angulação na aplicação da força. Os deslocamentos e as rotações do complexo zigomático-maxilar diminuíram gradualmente com o aumento de 10° para 30° no ângulo de aplicação da força entre as miniplacas. A mandíbula apresentou deslocamento irrelevante, com rotação no sentido horário. Conclusões: Os efeitos do tratamento com I-SAMP foram corroborados, com um vislumbre dos padrões de deslocamento e das suturas envolvidas, que não existiam nos estudos com imagens 2D e 3D realizados anteriormente. A angulação dos elásticos Classe III ancorados esqueleticamente deve ser a menor possível, visto que o deslocamento do complexo zigomático-maxilar aumenta com a redução no ângulo dos elásticos.

Management of skeletal Class III with facial asymmetry using skeletal anchorage: 4-year follow-up.

INTRODUCTION: Skeletal Class III malocclusion with asymmetry is one of the most difficult problems to correct in orthodontics. A functional shift of the mandible in growing patients may occur accompanying a Class III, due to constricted maxillary arch and occlusal interferences. Studies have indicated that posterior unilateral crossbite develops early and has a low rate of spontaneous correction. It may further lead to development of mandibular and facial asymmetry by growth and displacement of mandible if left untreated in growing patients. OBJECTIVE: This article reports the clinical case of a thirteen-year-old female patient in CVMI transition stage that had maxillary hypoplasia with a developing facial asymmetry. RESULTS: The case was successfully managed with bone-anchored facemask therapy and with elimination of occlusal interferences with guided occlusion. Reverse twin block in the retention phase maintained the results achieved. CONCLUSION: A four-year follow-up evaluation revealed successful maintenance of the treatment results.

Management of skeletal Class III with facial asymmetry using skeletal anchorage: 4-year follow-up

ABSTRACT Introduction: Skeletal Class III malocclusion with asymmetry is one of the most difficult problems to correct in orthodontics. A functional shift of the mandible in growing patients may occur accompanying a Class III, due to constricted maxillary arch and occlusal interferences. Studies have indicated that posterior unilateral crossbite develops early and has a low rate of spontaneous correction. It may further lead to development of mandibular and facial asymmetry by growth and displacement of mandible if left untreated in growing patients. Objective: This article reports the clinical case of a thirteen-year-old female patient in CVMI transition stage that had maxillary hypoplasia with a developing facial asymmetry. Results: The case was successfully managed with bone-anchored facemask therapy and with elimination of occlusal interferences with guided occlusion. Reverse twin block in the retention phase maintained the results achieved. Conclusion: A four-year follow-up evaluation revealed successful maintenance of the treatment results.

RESUMO Introdução: A má oclusão de Classe III esquelética com assimetria é um dos problemas mais difíceis de se corrigir na Ortodontia. O desvio funcional da mandíbula em pacientes em fase de crescimento pode ocorrer acompanhado da Classe III, devido à atresia maxilar e interferências oclusais. Estudos têm indicado que a mordida cruzada posterior unilateral se desenvolve precocemente e apresenta baixo índice de correção espontânea. Isso pode levar ao desenvolvimento de assimetria mandibular e facial, resultante do crescimento e deslocamento da mandíbula, caso os pacientes não sejam tratados na fase de crescimento. Objetivo: O presente artigo relata o caso clínico de uma paciente com treze anos de idade, com IMVC em estágio de transição e que apresentava hipoplasia maxilar com assimetria facial em desenvolvimento. Resultados: O caso foi tratado com sucesso por meio de terapia com máscara facial osseossuportada, eliminando as interferências oclusais por meio de uma oclusão guiada. O uso do aparelho Twin-block reverso como contenção preservou os resultados atingidos. Conclusão: O acompanhamento após quatro anos confirmou a manutenção dos resultados do tratamento.

Separation and pain perception of Elastomeric, Kesling and Kansal separators.

INTRODUCTION: Various types of separators have been advocated, but the ideal separator should produce optimum separation with minimal pain and discomfort. OBJECTIVE: The objective of this study was to evaluate and compare the amount of separation achieved by three different types of separators (Elastomeric, Kesling and Kansal), and to assess the associated pain and discomfort. METHODS: A random single-blind split-mouth study was conducted on 108 patients seeking fixed orthodontic treatment, in which two different separators were used on each side in both the arches for a single patient. After five days, the amount of separation was measured with a feeler gauge. Visual Analogue Scale (VAS) scoring was performed by the patient on each day, to evaluate pain perception. Discomfort was evaluated by questionnaire filled by the patient at the time of separator removal. RESULTS: The greatest amount of separation was seen with the elastomeric separators, while the smallest separation was seen with Kansal separators. VAS scoring showed maximum pain at day 1 with all the three separator types. Highest pain was perceived in the Elastomeric separators group, followed by Kesling and Kansal separators, respectively. Statistically significant difference was found in VAS score of Elastomeric separators, when compared to both Kesling and Kansal, on day 1 and 2 (p= 0.001). Analysis of the questionnaires revealed that a greater number of patients experienced discomfort with elastomeric separators placement (69.4%), which was statistically significant (p< 0.01) when compared to the other two types of separators. Answers to the other questions were comparable, except for the need for medications, which was reportedly highest with elastomeric separators. CONCLUSION: Kesling separators produce adequate separation with minimal discomfort and pain, compared to Elastomeric and Kansal separators.

Separation and pain perception of Elastomeric, Kesling and Kansal separators

Abstract Introduction: Various types of separators have been advocated, but the ideal separator should produce optimum separation with minimal pain and discomfort. Objective: The objective of this study was to evaluate and compare the amount of separation achieved by three different types of separators (Elastomeric, Kesling and Kansal), and to assess the associated pain and discomfort. Methods: A random single-blind split-mouth study was conducted on 108 patients seeking fixed orthodontic treatment, in which two different separators were used on each side in both the arches for a single patient. After five days, the amount of separation was measured with a feeler gauge. Visual Analogue Scale (VAS) scoring was performed by the patient on each day, to evaluate pain perception. Discomfort was evaluated by questionnaire filled by the patient at the time of separator removal. Results: The greatest amount of separation was seen with the elastomeric separators, while the smallest separation was seen with Kansal separators. VAS scoring showed maximum pain at day 1 with all the three separator types. Highest pain was perceived in the Elastomeric separators group, followed by Kesling and Kansal separators, respectively. Statistically significant difference was found in VAS score of Elastomeric separators, when compared to both Kesling and Kansal, on day 1 and 2 (p= 0.001). Analysis of the questionnaires revealed that a greater number of patients experienced discomfort with elastomeric separators placement (69.4%), which was statistically significant (p< 0.01) when compared to the other two types of separators. Answers to the other questions were comparable, except for the need for medications, which was reportedly highest with elastomeric separators. Conclusion: Kesling separators produce adequate separation with minimal discomfort and pain, compared to Elastomeric and Kansal separators.

Resumo Introdução: diversos tipos de separadores de dentes já foram descritos e seu uso, justificado na literatura. Porém, o separador ideal deve produzir uma força adequada para realizar a separação com o mínimo de dor e desconforto. Objetivo: o objetivo do presente estudo foi avaliar e comparar a separação ortodôntica obtida por meio de três diferentes tipos de separadores (Elastômeros, Kesling e Kansal), bem como a dor e o desconforto a eles vinculados. Métodos: foi conduzido um estudo randomizado, cego e de boca dividida em 108 pacientes interessados em realizar tratamento ortodôntico, nos quais foram utilizados dois separadores diferentes, um em cada lado de ambas as arcadas de cada paciente. Cinco dias após a inserção dos dispositivos, a quantidade de separação foi mensurada com o auxílio de um medidor (calibrador de folga). Para avaliar a dor, os pacientes preencheram uma Escala Visual Analógica (EVA) a cada dia do estudo; e, para a avaliação do desconforto, preencheram um questionário no dia da remoção dos separadores. Resultados: os Elastômeros obtiveram a maior quantidade de separação, enquanto os separadores Kansal conseguiram a menor separação. A análise das EVAs apontou a maior intensidade de dor no primeiro dia, para os três tipos de separadores, sendo os maiores índices relatados no grupo de Elastômeros, seguido pelos grupos Kesling e Kansal, respectivamente. Diferenças estatisticamente significativas foram encontradas nas escalas EVA dos Elastômeros em comparação aos separadores Kesling e Kandal, nos dias 1 e 2 (p= 0,001). A análise dos questionários mostrou que um grande número de pacientes relatou desconforto após a inserção dos Elastômeros (69,4%), valor estatisticamente significativo em comparação aos outros dois tipos de separadores (p< 0,01). As respostas às outras questões foram semelhantes entre os grupos, com exceção da necessidade de uso de medicamentos, a qual foi maior no grupo dos Elastômeros. Conclusão: os separadores Kesling produziram uma separação adequada, com o mínimo de dor e desconforto, em comparação aos Elastômeros e separadores Kansal.