Accuracy of three-dimensional soft tissue profile prediction in orthognathic surgery.

PURPOSE: To evaluate the accuracy of three-dimensional (3D) soft tissue prediction in bimaxillary orthognathic surgery. METHODS: Cone-beam computed tomographs of 88 patients with class II (n = 46) and class III (n = 42) malocclusions, who underwent bimaxillary orthognathic surgery, were included in this retrospective study. 3D soft tissue prediction and postoperative outcome were compared by using ten landmarks of facial soft tissues. Patients' sex and age were also assessed. Results were analyzed using a mixed model methodology (p < 0.05). RESULTS: The success criterion adopted was a mean discrepancy of < 2 mm. Most mandibular landmarks indicated a tendency for underprediction with a downward direction in class II patients, with some values > 2 mm. In class III, there was overprediction with a downward direction for the mandibular landmarks, with values < 2 mm. More accurate results were found in female and older patients. CONCLUSIONS: 3D surgical planning showed clinically acceptable results for predicting soft tissues in patients undergoing bimaxillary orthognathic surgery, with more accurate results for class III patients. Although some differences were found when age and sex were interacted, a consistent association between these variables could not be stated. These results support the clinician, as accuracy can provide a strong guide to the surgeon when planning surgical orthodontic treatment.

A comparative study of the accuracy between two computer-aided surgical simulation methods in virtual surgical planning.

OBJECTIVE: The aim of this retrospective and observational study was to compare the accuracy of two different virtual surgical planning (VSP) protocols, namely, the CASS method and the modified CASS method. MATERIALS AND METHODS: The patients underwent bimaxillary orthognathic surgery, planned using either the CASS method or the modified CASS method. Linear and angular discrepancies between the VSP outcome and postoperative outcome for both groups were compared for maxilla, mandible, and chin segments. Aside from the comparison between both groups, additional criteria were used to determine the accuracy of the protocol based on a linear and angular difference between planned and actual outcomes of less than 2 mm and 4°, respectively. The intergroup comparisons were performed by one-way ANOVA, with the level of significance set at 5%. RESULTS: A total of 21 patients, of both genders, were assigned into group I (n = 11), planned with the CASS method, and group II (n = 10), planned with the modified CASS method. Both the CASS and modified CASS methods presented similar accuracy with regard to linear differences for the maxilla, mandible, and chin segments, except for ΔX for the mandibular segment, where the modified CASS method showed slightly better accuracy. However, there was a statistically significant difference with regard to angular differences in the chin segment, with the CASS method shown to be the more accurate. Aside from Δpitch for the chin segment, no linear or angular differences exceeded 2 mm or 4°. CONCLUSION: Although statistically significant differences were found with regard to angular measurements in the chin segment, the accuracy of the modified CASS method for virtual planning can be considered as clinically equivalent, with a performance comparable to that of the CASS method.

Accuracy of 3D virtual surgical planning for maxillary positioning and orientation in orthognathic surgery.

OBJECTIVE: This retrospective and observational study evaluated the accuracy of a 3D virtual surgical planning (VSP) for the maxillary positioning and orientation in patients undergoing bimaxillary orthognathic surgery, comparing the planned and postoperative outcomes. SETTING AND SAMPLE POPULATION: Seventy consecutive patients of both sexes, who were submitted to bimaxillary orthognathic surgery between 2015 and 2019 were included in our study. MATERIAL AND METHODS: The patients were evaluated by fusing preoperative planning and postoperative outcome using cone-beam computed tomography scan evaluation. Three-dimensional VSP and postoperative outcomes were compared by using three linear and three angular measurements. The main outcome interest was the difference between the VSP movement, and the surgical movement obtained. The success criterion adopted was a mean linear difference of <2 mm and a mean angular difference of <4°. RESULTS: Results were analysed using a linear mixed model with fixed and random effects, at α = .05. No significant statistical differences were found for linear and angular measurements between the planned and postsurgical outcomes (P > .05). All overlapping points presented values within the range considered clinically irrelevant (<2 mm; <1°). CONCLUSIONS: Three-dimensional VSP was executed with a high degree of accuracy. When comparing the planned and postsurgical outcomes, all overlapping points presented values within the range considered clinically irrelevant.

Strategy for Optimizing Airway Volume With Genioglossal Advancement Using Cutting Guide in the Treatment of Obstructive Sleep Apnea.

The genioglossus advancement muscle is a technique used to treat obstructive sleep apnea and depends on the precise location of the muscle insertion into the geniotubercle. The aim of this article was to present a case report about a 38-year-old male patient with obstructive sleep apnea even after undergoing uvulopalatopharyngoplasty and mentoplasty. A maxillo-mandibular advancement and genioglossus was proposed, for this a virtual planning of the surgical guide was done using a specialized software. The great advantage is to reduce the osteotomy by focusing precisely on the insertion of the muscle. The cutting guide facilitated the surgical procedure in all aspects and brought safety.

Vertical bone augmentation of posterior mandibular region: a description of two surgical techniques / Aumento ósseo em altura da região mandibular posterior: descrição de duas técnicas cirúrgicas

ABSTRACT Correction of severe vertical bone deficiency in the posterior region of mandibular alveolar ridge requires surgical management if implants are scheduled and cannot have primary stability. The aim of the present study is to report two cases; one treated with alveolar osteogenesis distraction and the other with segmental osteotomy with autologous graft interposition, by describing the surgical steps as well as show the results and experiences acquired with these techniques. We opted for these methods to reconstruct the posterior mandibular region after remarkable vertical bone loss based mainly by the height and thickness of the remaining bone. Alveolar osteogenic distraction is highly advisable when vertical deficiency is severe, and if these cases are treated with the segmental osteotomy and autologous graft interposition, complications as graft failure, necrosis and resorption are more prone to occur due to insufficient vascularization. After bone maturation and bone neoformation secondary to alveolar osteogenic osteogenic distraction and segmental osteotomy with autologous graft interposition, respectively, the two presented case reports were able to securely receive dental implants. In cases of vertical bone loss of the posterior mandibular region, both surgeries currently represent the best choice for bone gain prior dental implants placement for oral rehabilitation, without technical challenges, although biological evidence to assure the superiority of one technique over the other must be further investigated.

RESUMO A correção de deficiência óssea severa em altura na região posterior do rebordo alveolar da mandíbula requer tratamento cirúrgico caso a inserção de implantes dentários seja necessária e não se pode ter uma estabilidade primária. O objetivo do presente estudo é relatar dois casos; um tratado com distração osteogênica alveolar e o outro com osteotomia segmentar associada à interposição de um enxerto autógeno, descrevendo a sequência cirúrgica, bem como mostrar os resultados e as experiências adquiridas com essas técnicas. Optamos por esses métodos para reconstruir a região mandibular posterior baseados principalmente na altura e espessura óssea remanescentes. A distração osteogênica alveolar é altamente recomendável quando essa deficiência é avançada e, se esses casos são tratados com a osteotomia segmentar e interposição de enxerto autógeno, complicações como falha do enxerto, necrose e reabsorção são mais prováveis de ocorrer devido à vascularização sua insuficiente. Após os períodos de reparação e neoformação óssea secundária à distração osteogênica alveolar e à osteotomia segmentar com interposição de enxerto autógeno, respectivamente, os dois casos relatados estavam aptos a receberem seguramente os implantes dentários. Nos casos de perda óssea em altura na região mandibular posterior, ambas as cirurgias representam, atualmente, a melhor escolha para o ganho de estrutura óssea antes da colocação dos implantes dentários e reabilitação oral, sem muita complexidade quanto à técnica cirúrgica, embora ainda sejam necessário estudos posteriores para assegurar a superioridade de uma técnica em relação a outra.

Effectiveness of surgical decompression in the treatment of a calcifying cystic odontogenic tumor.

The calcifying odontogenic cystic tumor (CCOT) is a benign lesion of odontogenic origin characterized by an ameloblastoma-like epithelium with ghost cells that may calcify. Despite broadly considered as a cyst, some investigators prefer to classify it as a neoplasm. Clinically, it occurs predominantly during the third decade of life. No difference in gender prevalence has been observed nor predilection of the lesion between maxilla and mandible. The most affected region extends from the incisor tooth to bicuspids. The classic treatment of the lesion is full excision, although a different approach may be determined by the possible association with another odontogenic tumor. Depending on the tumor size and the vicinity with important structures, decompression may be undertaken before its complete removal. The present report describes a case of CCOT with large proportions, located at the right maxilla and extending to the maxillary sinus, nasal cavity, and orbital floor. The treatment option was surgical decompression as the initial procedure, with satisfactory outcome. After partial remission, the lesion was fully removed, and the post-operative follow-up was uneventful.

Nasotracheal tube wire support: a safety device in maxillofacial surgery technical note after five years of experience.

A well fixed endotracheal tube is essential for safety during general anesthesia. In maxillofacial surgeries, securely fixing a nasotracheal tube in place has always been problematic. The aim of this article is to describe a simple but effective technique to fasten the nasotracheal tube using a wire support that allows a full range of head movement without interference in the surgical field. During the last 5 years, this device was successfully used in almost two hundred patients with very few complications.

Glossectomia parcial em macroglossia relativa por indicação ortodôntica: relato de 2 casos / Portal glossectomy in relative macroglossy with orthodontic indication: two case reports

O equilíbrio das pressões da língua e dos lábio faz parte dos fatores responsáveis pela posição dos arcos dentais. A macroglossia é um importante fator etiológico de algumas más oclusões ou gera instabilidade no pós-tratamento ortodôntico. Seu diagnóstico é baseado nos achados clínicos, podendo ser usados também dados da cefalometria. Pode ser considerada como anomalia verdadeira ou relativa. A indicação cirúrgica se faz após tentativa de tratamento fonoaudiológico quando há obstrução de vias aéreas, dificultando na fala e instabilidade dos arcos dentais. Várias são as técnicas usadas para a glossectomia parcial. Relatamos dois casos de macroglossia relativa que impediam a finalização do tratamento ortodôntico onde foi necessária a glossectomia parcial. Este trabalho tem a proposta de discutir o diagnótico, as indicações do tratamento e relatar as técnicas cirúrgicas que podem ser utilizadas