The Hyrax appliance with tooth anchorage variations in surgically assisted rapid maxillary expansion: a finite element analysis.

PURPOSE: It is known that a correct transverse maxillary dimension is a key factor for a stable occlusion, which brings functional and esthetic benefits for the patient. In patients presenting maxillary atresia and the completion of bone growth, a highly recommended option for correction is the surgically assisted rapid maxillary expansion (SARME) associated with the Hyrax appliance. The objective of this study was to evaluate the influence of tooth anchorage variations of the Hyrax appliance in SARME through finite element analysis, evaluating which anchorage option might be associated with more effective orthopedic results with less undesired side effects. METHODS: Five different dental anchoring conditions for the Hyrax appliance were simulated through FE analysis applying premolars and molars as anchorage, having the same force applied by the activation of the Hyrax screw (0.5 mm) in all groups. The maxillary displacement results (axes X, Y, and Z) and generated stresses for both teeth and maxillary bone were calculated and represented using a color scale. RESULTS: All groups presented significant bone displacement and stress concentration on anchoring teeth, with the group presenting anchorage in the 1st and 2nd molars showing the greatest maxillary horizontal displacement (axis X) and suggesting the lowest tendency of dental vestibular inclination. CONCLUSIONS: Variations in dental anchorage might substantially affect the maxillary bone and teeth displacement outcome. The protocol for the Hyrax apparatus in SARME applying the 1st and 2nd molars as anchorage might generate less tilting and inclination of the anchoring teeth.

Ameloblastoma folicular extensivo em mandíbula / Extensive follicular ameloblastoma in the mandible

O ameloblastoma é um tumor odontogênico benigno, de grande variação histológica, com alguns tipos apresentando alta propensão para recorrência. Diversos tratamentos são indicados, incluindo uma abordagem mais conservadora, desde a curetagem e a marsupialização até as mais radicais, como ressecções parciais ou totais da área afetada. O presente trabalho tem como objetivo proceder a uma revisão de literatura, abordando aspectos, a exemplo dos diferentes tipos de tratamento, algumas limitações e vantagens das técnicas, bem como apresentar um relato de um caso clínico conduzido pela equipe de Cirurgia e Traumatologia Buco-Maxilo-Facial no Hospital Nossa Senhora da Conceição (Tubarão/SC) de um paciente submetido à exérese de ameloblastoma multicístico e reconstrução imediata com enxerto de costela flutuante livre do lado direito, com resultado satisfatório na reabilitação do caso, restabelecendo o contorno anatômico e a função condilar... (AU)

The ameloblastoma is a benign tumor that has a great histological variation, being that in some types show high tendency of being recurring. Several treatments are indicated, including a more conservative approach, like curettage and marsupialization, even the most radical ones, like partial or total resection of the infected area. This paper aims to make a revision of literature, approaching aspects like the different types of treatment, some of its limitations and technical advantages, as well as show a clinical case conducted by the Oral and Maxillofacial surgery and traumatology team at NossaSenhora da Conceição Hospital (Tubarão /SC) of a patient subjected to exeresis of multicisticameloblastoma and immediate reconstruction with right side floating rib graft, showing a satisfactory result on the rehabilitation of the case, reestablishing the anatomic shaping and condylar function... (AU)

Giant Peripheral Temporomandibular Osteoma With Immediate Reconstruction of Mandible.

Osteoma is a benign osteogenic tumor, which is characterized the slow-growing proliferation of compact or cancellous bone. The etiology of the lesion is not well established. Among the hypotheses, the following are related: a traumatic factor, infectious processes, or true neoplasm due to the origin of cartilaginous cells. It can present at any age, usually in young adult individuals, with equal prevalence in both sexes. The clinical characteristics of the peripheral osteoma are represented by slow asymptomatic growth, which leads to swelling and, thus, facial asymmetry. When it is related to the mandibular condyle, this growth can cause functional impairment, such as malocclusion, temporomandibular joint dysfunction, and even limited mouth-opening owing to ankylosis.

Assessment of the Postoperative Stability of Mandibular Orthognathic Surgery for Correction of Class III Skeletal Malocclusion.

To assess the stability of mandible position after orthognathic surgery for correction of class III skeletal malocclusion. Twenty adult males, aged 18 to 40 years, with Angle class III skeletal malocclusion underwent preoperative orthodontic treatment for elimination of dental compensations followed by combined maxillomandibular surgery with rigid internal fixation. Lateral cephalograms from each patient, obtained in the natural head position before surgery, immediately after surgery, and at 6-month follow-up, were retrieved from the files of the Pontifical Catholic University of Rio Grande do Sul outpatient Oral and Maxillofacial Surgery clinic and compared. Comparison of craniometric landmark measurements showed that the precision of mandibular setback was compromised in the horizontal plane, with a mean mandibular relapse of 37.75% at point B and 45.85% at point Pg. Improved intercuspation and adaptation of the musculature to the new position of the jaws after orthognathic surgery lead to counterclockwise rotation of the mandible, ultimately displacing the mandible more anteriorly than desired.

Comparison of Neck Screw and Conventional Fixation Techniques in Mandibular Condyle Fractures Using 3-Dimensional Finite Element Analysis.

PURPOSE: To compare the mechanical stress on the mandibular condyle after the reduction and fixation of mandibular condylar fractures using the neck screw and 2 other conventional techniques according to 3-dimensional finite element analysis. MATERIALS AND METHODS: A 3-dimensional finite element model of a mandible was created and graphically simulated on a computer screen. The model was fixed with 3 different techniques: a 2.0-mm plate with 4 screws, 2 plates (1 1.5-mm plate and 1 2.0-mm plate) with 4 screws, and a neck screw. Loads were applied that simulated muscular action, with restrictions of the upper movements of the mandible, differentiation of the cortical and medullary bone, and the virtual "folds" of the plates and screws so that they could adjust to the condylar surface. Afterward, the data were exported for graphic visualization of the results and quantitative analysis was performed. RESULTS: The 2-plate technique exhibited better stability in regard to displacement of fractures, deformity of the synthesis materials, and minimum and maximum tension values. The results with the neck screw were satisfactory and were similar to those found when a miniplate was used. CONCLUSION: Although the study shows that 2 isolated plates yielded better results compared with the other groups using other fixation systems and methods, the neck screw could be an option for condylar fracture reduction.

Modified submandibular access for open reduction and internal rigid fixation in condylar fractures.

PURPOSE: The purpose of the present study was to describe a surgical technique for treatment of condylar fractures through the modified submandibular access, by means of a small incision in the mandibular angle that promotes a dissection between the parotideomasseteric and the transmasseteric fascia in a quick way and with low morbidity. Fixation may be made with plates and screws according to the technique prescribed by the surgeon. METHODS: Owing to the high incidence and importance of condylar fractures, various therapeutic methods have been described and may be divided into conservative and surgical methods. Various open surgical techniques are recommended in the treatment of mandibular condylar fractures, and the methods of internal rigid fixation and surgical accesses vary. The techniques that offer an adequate treatment of these fractures with shorter surgical time very often remain matters of controversy among surgeons. The procedure must guarantee maximum safety for the facial nerve and must provide a good cosmetic outcome, besides providing a suitable surgical field. RESULTS: A modified submandibular access is a safe and reproducible procedure providing excellent functional results. This procedure has been routinely performed in our department.

Fratura panfacial: relato de caso / Panfacial fracture: case report

Relatar um caso clínico de fratura panfacial, ressaltando a complexidade deste tipo de trauma e a abordagem de tratamento cirúrgico escolhida. Discussão: Um paciente de gênero masculino, 25 anos, deu entrada no Hospital Universitário do Oeste do Paraná, vítima de acidente automobilístico com múltiplas fraturas na face e evisceração do olho esquerdo. Permaneceu internado na UTI por vinte dias e, após melhora clínica, foi submetido à cirurgia para redução e fixação das fraturas faciais. Optou-se pela sequência de redução “de superior para inferior e de lateral para medial”. O paciente permaneceu com bloqueio intermaxilar por quinze dias, pois não se tratava de paciente colaborador. Evoluiu com mínimas sequelas estéticas e com uma oclusão estável. Conclusão: As fraturas panfaciais traduzem-se pelo tipo mais complexo de trauma facial e exigem conhecimento apurado por parte do operador. Existem várias sequências propostas para a redução dessas fraturas e cabe ao cirurgião bucomaxilofacial o diagnóstico e a escolha do melhor tratamento para o paciente...

To report a case of panfacial fracture, highlighting the complexity of this type of trauma and the surgical approach chosen. Discussion: A male patient aged 25 was admitted to the University Hospital of the West of Paraná, victim of a car accident with multiple fractures in the face and evisceration of the left eye. He remained in the ICU for twenty days and after clinical improvement underwent surgery for reduction and fixation of facial fractures. We opted for the reduction sequence “from top to bottom and from lateral to medial”. The patient remained with intermaxillary fixation for fifteen days because he was not a collaborative patient.He evolved with minimal aesthetic sequelae and with a stable occlusion. Conclusion: Panfacial fractures translateinto the most complex type of facial trauma and require thorough knowledge of the operator. There areseveral sequences proposed to reduce these fractures and the maxillofacial surgeon should diagnose and choosethe best treatment for the patient...