Mechanical Evaluation of Different Stable Internal Fixation Techniques of Sagittal Osteotomy in Mandibular Advance / Evaluación Mecánica de Diferentes Técnicas de Fijación Interna Estable de Osteotomía Sagital en Avance Mandibular

The mandibular advancements performed in orthognathic surgeries can be stabilized with several techniques when using stable internal fixation. This study aims to comparatively evaluate, in vitro, the mechanical strength in a polyurethane mandibular model for four fixation techniques for sagittal split ramus osteotomy mandibular. 60 samples were divided into 4 groups, with 15 units for each group: group A, group B, group C and group D. Advances of 5 mm were made for each subgroup and fixed with 2.0 mm system plates and monocortical screws in the replicas of human hemimandibles in polyurethane resin. The samples were submitted to mechanical tests of linear loading, being evaluated the peak load and peak deformation. Technique B presented higher peak load (Kgf) and techniques A and B presented higher peak strain (p<0.05). Technique D presented lower peak load and lower peak strain (p<0.05). It is concluded that the study based on the development of new techniques for fixation for sagittal osteotomy of the mandibular ramus is of great importance for the advancement of orthognathic surgery, provided by the technical innovation of more favorable plate models.

Los avances mandibulares realizados en cirugías ortognáticas pueden estabilizarse con varias técnicas cuando se utiliza fijación interna estable. Este estudio tuvo como objetivo evaluar comparativamente, in vitro, la resistencia mecánica en un modelo mandibular de poliuretano para cuatro técnicas de fijación para la osteotomía sagital de la rama mandibular. Se dividieron 60 muestras en 4 grupos, con 15 unidades para cada grupo: grupo A, grupo B, grupo C y grupo D. Se realizaron avances de 5 mm para cada subgrupo y se fijaron con placas de sistema de 2,0 mm y tornillos monocorticales en las réplicas de hemimandíbulas humanas en resina de poliuretano. Las muestras fueron sometidas a pruebas mecánicas de carga lineal, siendo evaluadas la carga máxima y la deformación máxima. La técnica B presentó mayor pico de carga (Kgf) y las técnicas A y B presentaron mayor pico de deformación (p<0,05). La técnica D presentó menor carga máxima y menor tensión máxima (p<0,05). Se concluye que el estudio basado en el desarrollo de nuevas técnicas de fijación para la osteotomía sagital de la rama mandibular es de gran importancia para el avance de la cirugía ortognática, proporcionada por la innovación técnica de modelos de placas más favorables.

Comparação da fragilidade gerada por 3 diferentes osteotomias sagitais de mandíbula: estudo in vitro / Comparison of fragility generated by 3 different sagittal mandible osteotomies: in vitro study / Comparación de la fragilidad generada por 3 osteotomías mandibulares sagitales diferentes: estudio in vitro

A osteotomia sagital bilateral de mandíbula (OSBM) foi publicada por Trauner e Obwegeser em 1957, desde então sofreu várias modificações a fim de diminuir as complicações e tornar o procedimento mais simples e previsível. Sendo assim objetivo do presente trabalho foi avaliar e comparar a fragilidade causada na mandíbula por 3 tipos de OSBM. Para isso, foram realizadas as osteotomias propostas por Trauner e Obwegeser modificada por Hunsuck e Epker (I), a de Sant'Ana (II) e de Wolford (III), em 24 hemimandibulas de poliuretano e foi realizado o ensaio mecânico para gerar a fratura sagital. Os dados foram coletados e tabulados, e obteve como resultado que, a maior quantidade de força máxima aplicada foi observada no grupo III, e a menor quantidade no grupo II; com relação à deflexão, apresentou significância estatística entre o grupo II e grupo III; com relação à rigidez, a maior média, foi encontrada no grupo I. Sendo assim, foi possível concluir que dentro deste modelo de estudo a osteotomia II foi capaz de gerar maior fragilidade à hemimandibula de poliuretano com menor quantidade de força. As OBMD dos grupos I e a III também apresentaram ótimos resultados, entretanto necessitaram mais força para alcançar a fratura... (AU)

The bilateral sagittal split osteotomy of the mandible (BSSO) was published by Trauner and Obwegeser in 1957, since then it has undergone several modifications in order to reduce complications and make the procedure simpler and more predictable. Therefore, the objective of this study was to evaluate and compare the fragility caused in the mandible by 3 types of BSSO. For this, the osteotomies proposed by Trauner and Obwegeser modified by Hunsuck and Epker (I), Sant'Ana (II) and Wolford (III) were performed on 24 polyuretha ne hemimandibles, a mechanical test to generate the sagittal fracture. Data were collected and tabulated, and the result was that, the highest amount of maximum force applied was observed in group III, and the lowest amount in group II; with regard to deflection, it was statistically significant between group II and group III; with regard to stiffness, the highest average was found in group I. Therefore, it was possible to conclude that within this study model, osteotomy II was able to generate greater fragility to the polyurethane hemimandible with less force. The BSSO of the groups I and III also showed excelent results, however they required more force to reach the fracture... (AU)

La osteotomía sagital bilateral de la mandíbula (OSBM) fue publicada por Trauner y Obwegeser en 1957, desde entonces ha sufrido varias modificaciones con el fin de reducir las complicaciones y hacer el procedimiento más simple y predecible. Por lo tanto, el objetivo de este estudio fue evaluar y comparar la fragilidad causada en la mandíbula por 3 tipos de OSBM. Para eso, se realizaron las osteotomías propuestas por Trauner y Obwegeser modificadas por Hunsuck y Epker (I), Sant'Ana (II) y Wolford (III) en 24 hemimandíbulas de poliuretano y se realizó un ensayo mecánico para generar la fractura sagital. Los datos fueron recolectados y tabulados, obteniendo como resultado que, la mayor cantidad de fuerza máxima aplicada se observó en el grupo III, y la menor cantidad en el grupo II; en cuanto a la deflexión, fue estadísticamente significativa entre el grupo II y el grupo III; en cuanto a la rigidez, la media más alta se encontró en el grupo I. Por lo tanto, se pudo concluir que, dentro de este modelo de estudio, la osteotomía II logró generar mayor fragilidad a la hemimandíbula de poliuretano con menor fuerza. El OSBM de los grupos I y III también mostró excelentes resultados, pero requirieron mayor fuerza para llegar a la fractura... (AU)

Manejo quirúrgico de bad split bilateral en cirugía ortognática / Surgical management of bilateral bad split during orthognathic surgery

El bad split es un término clínico que refiere a una fractura no planificada que ocurre al momento de realizar una osteotomía sagital de rama mandibular (OSRM). Afecta aproximadamente al 2,3% de los pacientes y se han descrito factores de riesgo tales como la presencia de terceros molares mandibulares, edad avanzada al momento de la cirugía, técnica de osteotomía inadecuada, entre otros. Se recomienda efectuar manio-bras preventivas para evitar la aparición de patrones de fractura no deseados al realizar la OSRM. Sin embargo, al momento de pesquisar un bad split, éste debe ser tratado por un equipo capacitado y de manera oportuna para evitar retardo en la consolidación, infecciones y secuestros óseos que puedan comprometer los resultados de la cirugía. En este artículo se presenta el manejo de un caso clínico de bad split bilateral intraoperatorio por el Servicio de Cirugía Maxilofacial del Hospital San José, enfatizando su tratamiento quirúrgico.

Bad Split is a clinical term referring to an unplanned fracture that occurs during the bilateral sagittal split osteotomy (BSSO). It affects approximately 2,3% of the patients undergoing orthognathic surgery and several risk factors have been described such as the presence of mandibular third molars, advanced age at the moment of orthognathic surgery, inadequate osteotomy technique, etc. Preventive maneuvers are recommended in order to avoid the appearance of undesired fracture patterns during BSSO. However, if a bad split is detected it must be managed and treated by a qualified team to avoid further complications such as delayed bone consolidation, bone infection and necrosis. In this article we present the management of a case of bilateral bad split by the Maxillofacial Surgery Service of Hospital San José, emphasizing on its surgical treatment.

Does the presence of third molars during sagittal split mandibular ramus osteotomy favour complications? Systematic review and meta-analysis.

The aim of this systematic review and meta-analysis was to assess whether the presence of inferior third molars during sagittal split mandibular ramus osteotomy increases the risk of intraoperative and postoperative complications. The PRISMA protocol was followed in this study, and the review was registered in the PROSPERO database (CRD42020147642). A search was conducted in the MEDLINE (PubMed), Web of Science, Cochrane Central, and Scopus databases on November 1, 2021. Nineteen articles were included, and the variables analysed were unfavourable fractures, infection, neurosensory disturbance, removal of osteosynthesis material, and duration of surgery. Meta-analyses were performed for the variables unfavourable fractures (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.58-1.57, P = 0.84), infection (RR 0.75, 95% CI 0.48-1.18, P = 0.21), and neurosensory disturbance (RR 1.55, 95% CI 0.61-3.91, P = 0.35); no statistically significant difference in the risk of these variables was found between the groups with and without third molars. The third molars did not increase the need to remove fixation material, but increased the surgery time. The presence of the third molar during sagittal split mandibular ramus osteotomy appears not to increase the risk of intraoperative and postoperative complications. The results presented here must be interpreted with caution due to the heterogeneity presented by the observational studies included.

Is it necessary to use bone grafts to prevent defects at the lower border of the mandible after mandibular advancement?-a systematic review.

INTRODUCTION: Defects in the lower border of the mandible may represent an aesthetic problem after mandibular advancement in orthognathic surgery. The use of bone grafts has been reported in the literature as a possibility to reduce these defects in the postoperative period. OBJECTIVE: The objective of this systematic review is to answer the following research question: Is it necessary to use bone grafts to prevent defects at the lower border of the mandible after mandibular advancement? METHODS: The literature search was conducted on MEDLINE via PubMed, Scopus, Central Cochrane, Embase, LILACS, and Sigle via Open Gray up until December 2020. Five studies were eligible for this systematic review, considering the previously established inclusion and exclusion criteria. RESULTS: 1340 mandibular osteotomies were evaluated, with a mean advance of 8 mm, being 510 with bone graft (42 defects), 528 without graft (329 defects), and 302 with an alternative technique (32 defects). Regarding the type of bone graft used, three articles used xenogenous or biomaterial grafts and two allogenous bone grafts. The results of the meta-analysis showed a reduction in the presence of defects in the bone graft group: OR 0.04, 95% CI = 0.01, 0.19; p = 0.0005, (I2 = 87%; p < 0.0001). CONCLUSION: The use of bone grafts seems promising in reducing defects in the lower border of the mandible after mandibular advancement. New controlled prospective studies with a larger number of participants are needed to ensure the effectiveness of this procedure.

Does the type of sagittal split ramus osteotomy influence fixation strength? Evaluation of the mechanical behavior of two types of fixation used in three types of sagittal split ramus osteotomy.

PURPOSE: This study compared the mechanical behavior of two fixation techniques used in three sections representing the sagittal split ramus osteotomy (SSRO) in polyurethane replicas that were divided into groups, according to type of section, and sub-groups according to type of fixation, simulating 11-mm advancement and 6º clockwise mandibular rotation. METHODS: Loads were applied in two regions, aiming at progressive application and consequent strength value, measured in kilogram-force in displacements of 1, 3, 5, and 7 mm, from the load application tip. Shapiro-Wilk test was performed, followed by two-way analysis of variance (ANOVA-2 way), and Bonferroni's multiple comparison. RESULTS: The results showed no statistically significant difference in the type of section and type of fixation used when load was applied to the inter-incisor region. However, when load was applied to the first molar region, statistically significant difference was observed in 1-mm displacement, in which section described by Epker with two modifications showed greater strength, regardless of type of fixation used (p = 0.007). CONCLUSION: In the application of load in the inter-incisor region, there was no statistical difference between the type of osteotomy and the type of fixation used. When applying loads to molars, there was a difference for the type of osteotomy, where the Epker osteotomy with 2 modifications presented greater resistance, regardless of the type of fixation used.

Influence of the mandibular plane and magnitude of the movement in sagittal split ramus osteotomy: an in vitro study.

PURPOSE: The aim of this study was to evaluate fixation resistance in mandibular sagittal split ramus osteotomy in standardized polyurethane hemimandibles with two types of advancement (6 and 12 mm), with or without mandibular plane rotation, using a 2.0-mm plate/screw system. METHODS: Seven groups were evaluated using a vertical compressive load in the first molar region, and the applied force in Newtons was recorded in 1 mm, 5 mm, and 10 mm displacements, as well as the maximum force. RESULTS: There was a statistical intergroup difference and it was observed that increasing the advancement decreased fixation resistance with a single plate, and inserting an additional plate significantly increased osteosynthesis resistance. CONCLUSION: In the 12 mm advancements, clockwise rotation proved to be more resistant when fixed with only one plate. By contrast, counterclockwise rotation was significantly more resistant in stabilizing the mandibular sagittal ramus osteotomy when two plates were used.

Treatment of Dentofacial Deformity Associated with Temporomandibular Joint Ankylosis Through Vertical and Sagittal Osteotomies of the Mandibular Ramus.

ABSTRACT: Ankylosis of the temporomandibular joint is a disorder resulting from fibrous, osseous, or fibro-osseous adhesion that directly affects the quality of life of the individual. The authors present a case of unilateral temporomandibular joint ankylosis treated by condilectomy and ipsilateral sliding vertical ramus osteotomy associated with contralateral sagittal osteotomy aiming to restore function and to correct dentofacial deformity class II. A 31-year-old female patient presented with a history of facial trauma and major complaint of oral opening limitation. Physical examination revealed hypoplasia of the lower third of the face, facial pattern type II, anterior open bite, and maximum mouth opening of 22.5 mm. Computed tomography showed an ankylotic mass in the right mandibular condyle with deformity of the condylar structure and fusion to the right zygomatic arch and a contralateral condylar fracture sequel. It was proposed to perform a condilectomy of the right mandibular condyle for the removal of the bone mass concomitant to the sliding vertical ramus osteotomy of the mandibular ramus for condylar reconstruction by rhytidectomy approach and the sagittal osteotomy of the left mandibular aiming the reestablishment of occlusion and the correction of dentofacial deformity. The condylar fracture was not operated because the condyle was remodeled. The patient is in her fourth year postoperative presenting satisfactory esthetic-functional re-stabilization, without clinical signs of recurrence. In conclusion, the authors believe that combined sliding vertical ramus osteotomy and sagittal osteotomy can bring satisfactory results in complex cases.

Do lower third molars increase the risk of complications during mandibular sagittal split osteotomy? Systematic review and meta-analysis.

The aim of this systematic review was to investigate whether the presence of third molars (3Ms) during sagittal split osteotomy of the mandible increases the risk of complications. Searches were conducted using MEDLINE via PubMed, LILACS, Cochrane Central, Scopus, DOSS, and SIGLE via OpenGrey up to December 2020. Fifteen articles were included for evaluation and 14 in the meta-analysis, with a total of 3909 patients and 7651 sagittal split osteotomies (670 complications). Inferior alveolar nerve (IAN) exposure in the proximal segment was the most frequent complication (n = 409), followed by bad splits (n = 151). Meta-analysis revealed no significant increase in the incidence of 3M-related IAN exposure (P = 0.45), post-surgical infections (P = 0.15), osteosynthesis material removal (P = 0.37), or bad splits (P = 0.23). The presence of 3Ms was associated with a reduced risk of nerve disorder (P = 0.05) and favoured bad splits in the lingual plate (P = 0.005). The quality of evidence was very low, mainly due to non-randomized study designs, high risk of bias, inconsistency, and imprecision. This systematic review suggests that the removal of 3Ms before sagittal mandibular osteotomy does not reduce the incidence of complications. Thus, we recommend future better-designed studies with rigorous methodologies and adjustments for confounding factors.

Estabilidad del tratamiento ortodóncico-quirúrgico de avance mandibular mediante osteotomía sagital bilateral de rama mandibular en pacientes clase II. Revisión narrativa / Stability of the orthodontic-surgical treatment of mandibular advancement through bilateral sagittal split osteotomy in class II patients. Narrative review

RESUMEN: Introducción: La anomalía esqueletal clase II posee un 16 a 22,5% de prevalencia mundial. Cuando estos pacientes se someten al avance mandibular mediante osteotomía sagital de rama mandibular pueden presentar un grado de inestabilidad postoperatoria evidenciándose como recidiva de éste. Objetivo: Describir la estabilidad del avance mandibular mediante osteotomía sagital bilateral de rama mandibular en pacientes clase II esqueletal. Material y método: Se realizó una búsqueda electrónica en las bases de datos PubMed, EBSCO, The Cochrane Library, Tripdatabase y Scopus mediante las palabras clave "mandibular stability", "skeletal stability", "mandibular advancement", "sagittal split osteotomy", "sagittal split ramus osteotomy", "class II", "class III" y "distraction osteogenesis", relacionadas entre sí con los términos booleanos AND, OR y NOT. También se incluyeron los términos MeSH "mandibular advancement" y "Sagittal Split Ramus Osteotomy". Paralelamente se realizó una búsqueda manual en las revistas AJODO, BJOMS, JOMS y EJO. Resultados y discusión: Se seleccionaron 29 artículos: 24 estudios observacionales analíticos, 2 revisiones sistemáticas y 3 ensayos clínicos aleatorizados. El avance mandibular mediante osteotomía sagital de rama mandibular es estable. No obstante, se debe tener en cuenta la existencia de múltiples factores pre e intraquirúrgicos que podrían generar recidiva del tratamiento.

ABSTRACT: Introduction: The class II skeletal anomaly has a 16-22,5% prevalence worldwide. When class II patients undergo mandibular advancement through Bilateral Sagittal Split Osteotomy (BSSO), they can present a postoperative instability, evidenced as a relapse. Objective: To describe the stability of mandibular advancement through BSSO in skeletal class II patients. Materials and method: An electronic search was performed in the databases PubMed, EBSCO, The Cochrane Library, Tripdatabase and Scopus using the keywords "mandibular stability", "skeletal stability", "mandibular advancement", "sagittal split osteotomy", "sagittal split ramus osteotomy", "class II", "class III" and "distraction osteogenesis", related to each other with the Boolean terms AND, OR and NOT. Also "mandibular advancement" and "Sagittal Split Ramus Osteotomy" MeSH terms were included. In parallel, a manual search in the journals AJODO, BJOMS, JOMS and EJO was performed. Results and discussion: 29 articles were selected: 24 analytic observational studies, 2 systematic reviews and 3 randomized clinical trials. Mandibular advancement through BSSO is stable. However, multiple pre and intraoperative factors that could cause a treatment relapse must be taken into account.

Postoperative neurosensory impairment perception using ultrasonic BoneScalpel and conventional rotary instruments after bilateral split sagittal osteotomy.

PURPOSE: Although bilateral sagittal split osteotomy (BSSO) is the most widely used surgical technique for the correction of mandibular dentofacial anomalies, it is associated with lesion of inferior alveolar nerve (IAN) and unwanted neurosensory disorders. The aim of this study was to document the perception of changes in sensitivity and mean recovery time after BSSO, using an ultrasonic BoneScalpel versus the conventional rotary instruments. PATIENTS AND METHODS: This retrospective observational study included all patients with diagnosis of skeletal anomaly who underwent advancement or setback BSSO of less than 10 mL, using the ultrasonic osteotome or conventional rotary instruments. The patients were operated on at the Hospital Universitario Clínica San Rafael, Bogotá Colombia, between 2017 and 2018. The primary predictor variable was the osteotomy technique. The primary outcome was the presence or absence of postoperative sensory alteration, whereas secondary outcomes were time of appearance and recovery, affected anatomical region, laterality, and disturbance in daily activities. Data were analyzed using Chi-square, Mann-Whitney U, and Fisher's exact test. RESULTS: Data of 38 patients were retrieved, of which 23 were operated with BoneScalpel and 13 with the conventional technique. Twenty patients were women and 18 were men. All patients reported experiencing at least one type of sensory disturbance immediately after the surgical procedure. There was a significant difference (p = 0.0001) in the time that the alteration was present between the two groups, in favor of the BoneScalpel group. The chin and the lower lip were the anatomical regions with the greatest alteration in sensitivity and persistence of it. CONCLUSIONS: The results of this study indicate that BoneScalpel is effective in performing BSSO. They also suggest that it may reduce the occurrence of nerve damage during BSSO, although more research on this topic is required.

Which type of method shows the best mechanical behavior for internal fixation of bilateral sagittal split osteotomy in major advancements with clockwise rotation? Comparison of four methods.

PURPOSE: The aim of the present study was to evaluate the four methods for bilateral sagittal osteotomy fixation. METHODS: In this study, 56 replicas of whole mandibles made of rigid polyurethane were used. After simulation of major advancement (11 mm) with clockwise rotation of the mandible (6o) in relation to the occlusal plane, the bone segments were fixed with plates and screws of the 2.0-mm system on both the right and left sides: group I, double "H" plate; group II, two mini-plates; group III, "hybrid technique"; and group IV, three bicortical screws in the "inverted L" pattern. The mandibles were submitted to load on the central incisors and right first molar. RESULTS: The mean value of group I was higher than those of groups IV and II in the displacement of 1 mm (F = 4.705; p = 0.010) with load on the incisor. The mean value of group III was higher than those of groups I and II in the displacement of 1 mm (F = 5.166; p = 0.007) and 3 mm (F = 5.166; p = 0.007). The mean value of group IV was higher than that of group II (F = 3.142; p = 0.044) with load on the molar. CONCLUSION: Therefore, after the analyses, the hybrid technique was the one that showed the best results.

Is Low-Level Laser Therapy Effective on Sensorineural Recovery After Bilateral Sagittal Split Osteotomy? Randomized Trial.

PURPOSE: When performing a sagittal osteotomy of the mandibular ramus, one must consider the risk of long-term postsurgical sensory abnormalities from lesions to the inferior alveolar nerve. One treatment for these changes is low-level laser therapy (LLLT). Thus, the aim of this research was to evaluate the effectiveness of LLLT on sensorineural recovery after split ramus osteotomy of the mandible. MATERIALS AND METHODS: This randomized, double-blinded, split-mouth design trial included patients who underwent advanced surgery of the mandible and then received LLLT on 1 side of the mandible (experimental) and a random placebo (control) treatment on the opposite site. Patients were divided into 2 groups: group 1 was treated during the short postoperative period (within 30 days) and group 2 was treated for persistent sensory abnormalities during the late postoperative period (6 months to 1 yr). Each patient received 5 LLLT and control sessions with intervals of 3 to 4 weeks between sessions. The experimental side in each patient received LLLT in the extraoral area (mandibular ramus and entire length of the inferior alveolar nerve to the mental region) and the intraoral area (mental foramen region). The control side received simultaneous placebo treatments. The sensorineural response was analyzed before the onset of treatment and after each LLLT and control session using the Semmes-Weinstein monofilament test. RESULTS: Twenty adult patients (mean age, 35.6 years; 70.0% women) showed improvement in the experimental and control sides during the follow-up period. However, the experimental side in groups 1 and 2 exhibited a marked improvement in sensorineural recovery over the course of the sessions, and group 1 had the best results. CONCLUSION: LLLT was effective in the recovery from sensorineural disorders after orthognathic surgery during the short postoperative period, particularly in the fifth session.

Estudo comparativo entre dois programas de computador (Dolphin Imaging® e Nemotec®) e método manual para análises cefalométricas de pacientes com deformidade dentofacial Padrão II / Comparative study of two computer software programs (Dolphin Imaging® and Nemotec®) and a manual method of cephalometric analysis for patients with dentofacial deformity Class II

Este estudo analisou traçados digitais obtidos por dois programas de computador (Dolphin Imaging® e Nemotec®) em comparação aos obtidos pelo método manual nas análises cefalométricas SNA, SNB, Co-A, Co-Gn, altura facial anterior, A-Nperp, Pg-Nperp e plano mandibular. 30 pacientes leucodermas, portadores de retrognatismo mandibular, foram avaliados e submetidos à cirurgia ortognática para correção da deformidade por meio da osteotomia sagital do ramo mandibular. Os traçados cefalométricos foram realizados em telerradiografias laterais obtidas uma semana antes da cirurgia. O método Manual e o Nemotec® apresentaram excelente confiabilidade em todas as medidas. Por outro lado, o método Dolphin Imaging® apontou baixa confiabilidade nas medidas altura facial anterior, Co-A e Co-Gn. Nas medidas A-Nperp, Pg-Nperp, Plano md, SNA e SNB, não houve diferença entre três métodos estudados. Na medida altura facial anterior, houve diferença entre os métodos Dolphin Imaging® e Nemotec®, mas não foram observadas diferenças em relação ao método manual. Nas medidas Co-A e Co-Gn, foi observado que o método Dolphin Imaging® apresentou média significativamente inferior aos demais métodos estudados. No método manual, somente as medidas Co-Gn, Pg-Nperp e SNB confirmaram o diagnóstico de retrognatismo mandibular, tendo o programa Nemotec® apresentado resultados melhores que o programa Dolphin Imaging®... (AU)

This study analyzed digital tracings obtained by two different computer software programs (Dolphin Imaging® and Nemotec®) and compare them to the manual method using cephalometric measurements SNA, SNB, Co-A, Co-Gn, anterior facial height, A-Nperp, Pg-Nperp and mandibular plane. Thirty Caucasian patients exhibiting mandibular retrognathia were analyzed and were submitted to orthognathic surgery to correct the deformity by bilateral sagittal split osteotomy. The cephalometric tracings were performed with lateral radiographs that were obtained a week prior to the surgery. The manual method and the Nemotec® software exhibited an excellent reliability in all measurements. However, the Dolphin Imaging® method exhibited low reliability in the anterior facial height, Co-A and Co-Gn measurements. For the measurements of A-Nperp, Pg-Nperp, Mandibular plan, SNA and SNB, there were no significant differences between the three methods studied. For the anterior facial height measurement, a statistically significant difference was found between the Dolphin Imaging® and Nemotec® methods, although not in relation to the manual method. For the Co-A and Co-Gn measurements, the Dolphin Imaging® method exhibited a significantly lower mean than the other methods studied. In manual method, only the Co-Gn, Pg-Nperp and SNB measurements confirmed the diagnosis of mandibular retrognathia and Nemotec® software provided better results than Dolphin Imaging®... (AU)

Laser Biophotomodulation in Patients with Neurosensory Disturbance of the Inferior Alveolar Nerve After Sagittal Split Ramus Osteotomy: A 2-Year Follow-Up Study.

OBJECTIVE: To evaluate the effect of the application of photobiomodulation in a 2-year follow-up period in patients who have been intervened with a sagittal ramus split osteotomy and present neurosensory disturbance of the inferior alveolar nerve. BACKGROUND: Photobiomodulation is a common clinical tool in dentistry, for its beneficial effects have been shown in surgical and periodontal wound healing, reducing of swelling and pain, neurosensory recovery, and treatment of temporomandibular joint disorders. METHODS: This is a 2-year follow-up study with an experimental (Laser) group (n = 33) that received photobiomodulation, and a control (Sham) group (n = 9), placebo. All patients from the Laser group received laser applications (continuous wave of 0.353 W/cm2, 27 J in 270 sec per session) on days 1, 2, 3, 5, 10, 14, 21, and 28 after surgery. Neurosensory disturbance was evaluated with five tests: Visual Analog Scale (VAS) for pain and sensitivity, sensitivity threshold test, two-point discrimination, and thermal discrimination. All tests were performed before (24 h before surgery) and after surgery (24 h, 28 days, 60 days, 6 months, 1 year, 2 years, more than 2 years). Participants and evaluator were blinded to intervention. Variables were described with absolute frequencies, percentages, and medians. Ordinal and dichotomous variables were compared with Mann-Whitney's and Fisher's tests, respectively. RESULTS: Clinical improvement was observed during the follow-up period for the Laser group; general VAS for sensitivity was normal in 11 participants from the Laser group at 2 years postsurgery (40.74%), while no participants from the Sham group achieved this (p = 0.0341). Twenty-three participants recovered initial values for two-point discrimination (69.7%) after 2 years of follow-up (p = 0.0025) as well as sensitivity threshold test. General VAS for pain was normal in 31 patients from the Laser group after 2 years of follow-up (93.94%, p = 0.0254). CONCLUSIONS: Photobiomodulation was effective for neurosensory recovery on sample studied.

Use of Bone Grafts or Modified Bilateral Sagittal Split Osteotomy Technique in Large Mandibular Advancements Reduces the Risk of Persisting Mandibular Inferior Border Defects.

PURPOSE: Healing of the inferior border of the mandible can be compromised in large advancements, leaving an unesthetic defect at the inferior border. The objective of this study was to compare different bilateral sagittal split osteotomy (BSSO) techniques to prevent the incidence of lower border mandibular defects. MATERIALS AND METHODS: The authors undertook a retrospective multicenter cohort study comparing 3 BSSO techniques for advancements greater than 5 mm: traditional non-grafted BSSO (group A), traditional grafted BSSO (group B), and modified BSSO (group C). The space created by the mandibular advancement was measured. The presence or absence of a defect was determined 1 year after surgery by clinical and radiographic assessment. The bone defect outcome was associated with potential risk predictors (age, gender, side of SSO, and magnitude of mandibular advancement) by logistic regression analysis. RESULTS: A total of 1,002 operative sites in 501 patients were included in the study. Age (mean, 26.8 yr; standard deviation, 11 yr), gender (310 female, 191 male), and mandibular advancement (right, 9.3 mm; left, 10 mm) were similar among groups (P > .05). The proportions of postsurgical lower border mandibular defects were 54.5% in group A, 1.3% in group B, and 10.6% in group C. The traditional grafted and modified BSSO techniques were significantly more effective in preventing the incidence of mandibular lower border defects compared with the traditional non-grafted BSSO technique (P < .05). CONCLUSION: Surgeons are advised that the traditional non-grafted BSSO technique produces a large proportion of mandibular lower border defects. Use of bone grafts or the modified BSSO technique in mandibular advancements greater than 10 mm markedly decreases the risk of persisting mandibular inferior border defects.

Análise biomecânica de diferentes tipos de fixação em osteotomia sagital do ramo após diferentes avanços e alterações do plano mandibular: um estudo com elementos finitos / Biomechanical analysis of different types of fixation in sagittal ramus osteotomy after different advances and changes in the mandibular plane: a study with finite elements

O objetivo deste trabalho foi avaliar, por meio de um estudo com análise em elementos finitos, as tensões de superfície presentes na cortical óssea mandibular e no material de síntese, assim como avaliar a resistência da fixação ao deslocamento após a osteotomia sagital do ramo mandibular (OSRM) quando da realização de diferentes avanços mandibulares com e sem alteração do plano mandibular. Foram obtidos modelos virtuais tridimensionais de uma mandíbula e planejados avanços de 6 e 12mm com avanço linear, assim como associados ao giro horário e anti-horário do plano mandibular. Cada conjunto foi, então, fixado com uma ou duas placas monocorticais do sistema 2.0 dispostas horizontalmente com 4 parafusos em cada placa. Ao todo, foram construídos 12 modelos que foram então submetidos a uma carga vertical linear na região de incisivos centrais em incrementos de 50N até o limite máximo de 500N. Os resultados demonstraram que os avanços de 12mm estão associados a maiores tensões nas corticais ósseas e no material se síntese. Também foi possível concluir que os modelos fixados com duas placas apresentaram valores menores de tensão no material de síntese em comparação aos modelos fixados com uma placa. A mudança do plano mandibular no sentido anti-horário nos avanços de 6 mm, fixados com 1 ou 2 placas, aumentou a tensão no material de síntese, o que não ocorreu nos avanços de 12 mm. Esses resultados podem auxiliar os cirurgiões na tomada de decisão clínica diária (AU).

The aim of the present paper was to evaluate, via a finite element analysis, the tensions on the cortical bone and the plating system, as to evaluate mandibular resistance after the sagittal split ramus osteotomy with different mandibular advancements and mandibular plane movements. 3D mandibular models were obtained and a 6mm and 12mm advancement was planned associated with linear, clockwise or counter clockwise rotation of the mandibular plane angle. Each model was then fixed with one or two plates of the 2.0mm system and held with 4 monocortical screws at each side. A total of 12 models were built and they were subjected to a vertical load in the incisors region ranging from 50N to 500N in 50N increments. Results have shown that the 12mm advancement was associated with a higher tension in the cortical bone and plate surface. It was also concluded that the models fixed with 2 plates presented lower values of tension on the plates in comparison with the models fixed with a single plate. Counter clockwise rotation of the mandibular plane angle in the 6mm advancement, fixed with 1 or 2 plates, brought more tension to the plates, which did not occur in the 12mm advancements. These results may aid surgeons with decision making on a daily basis (AU).

Odontoma Compuesto: Diagnóstico y Tratamiente Reporte de Casos & Revisión de la Literatura / Compound Odontoma: Diagnosis and Treatment Therapeutic Measures. Case Reports & Literature Review

RESUMEN: Los odontomas son los tumores odontogénicos benignos más prevalentes. Estos están conformados por tejido dentario, epitelio odontogénico y tejido mesenquimático. Se dividen en dos subtipos: odontomas compuestos, que presentan tejidos dentarios normales, pero con una alteración en su conformación y tamaño, y odontomas complejos, que presentan tejidos dentarios bien formados, pero rodeados de tejido desorganizado. Se presentan tres casos de pacientes sexo femenino, quienes acuden para evaluación y tratamiento debido al hallazgo radiográfico de odontoma compuesto. En el caso nº 1 se realizó la desinclusión del diente impactado, la exodoncia del diente remanente, la exéresis del odontoma compuesto, la instalación de un implante dental en el alveolo de la zona intervenida y, finalmente, el posicionamiento de injerto óseo. En el caso nº 2 se realizó la exodoncia del diente temporal remanente y la exéreis del odontoma compuesto. Ambos casos evolucionaron de manera favorable sin complicaciones post operatorias. En el caso nº 3 se realizó la fenestración del diente 18 y la exéreis del odontoma compuesto que retenía su erupción. Todos los casos evolucionaron de manera favorable sin complicaciones post operatorias. Dada la prevalencia de esta patología, es necesario un adecuado conocimiento sobre ella y sus características, para realizar un adecuado diagnóstico y tratamiento. Existen distintas medidas terapéuticas respecto a la rehabilitación de una zona edéntula como resultado de la exéresis de estos tumores. Esto depende principalmente de la edad del paciente. Al ser requeridas medidas rehabilitadoras, un punto importante a considerar es la posibilidad de realizar todos los procedimientos quirúrgicos en un solo tiempo operatorio.

ABSTRACT: Odontomas are the most common benign odontogenic tumors and are composed of dental tissue, odontogenic epithelium and mesenchymal tissue. They are divided into two subtypes: Compound odontomas, which present normal tooth tissue, but an alteration in their conformation and size, and complex odontomas, which present well-formed tooth tissue, but are surrounded by disorganized tissue. A bibliographic review was performed by one operator in Pubmed and Epistemonikos. After filtering by title and abstract, only one systematic review was selected. We present two clinical cases of compound odontoma in female patients at the Military Hospital in Santiago. Patients were referred for evaluation and treatment due to the radiographic finding of compound odontoma. In case # 1, the impacted tooth was disincluded, the remaining temporal tooth was extracted, and excision of the compound odontoma carried out; subsequently a bone graft implant was placed in the remaining socket. In case # 2, the remaining temporal tooth was extracted and compound odontoma excised. After that, natural eruption of the corresponding permanent tooth is expected. In case # 3, tooth 1.8 fenestration and excision of compound odontoma was performed. In this case also, natural eruption of the corresponding permanent tooth is expected. Given the prevalence of this pathology, adequate knowledge of compound odontomas and their characteristics is necessary for proper diagnosis and treatment. There are different therapeutic measures for the rehabilitation of an edentulous area following excision of compound odontoma. This depends mainly on the age of the patient. When rehabilitation measures are required, an important aspect to consider for the patient, is the possibility of a single surgical event, as was done in case # 1.

Lingual Short Split: A Bilateral Sagittal Split Osteotomy Technique Modification.

The technique of sagittal split osteotomy of the mandibular ramus is an established technique that has been evolving over the years, with significant improvements regarding stability, better bone contact between the segments, and possibilities of osteosynthesis. However, paresthesia is common in the postoperatory, sometimes permanent, and undesirable fractures in the subcondylar region can occur leading to longer operative time and extraoral scars. The short lingual split technique is an easy technique that simplifies the horizontal osteotomy of the ramus and decreases the risk of undesirable fractures with a neurosensitive recovery of patients in a much shorter time because of minor trauma and nerve manipulation during the execution.

Osteotomia sagital do ramo mandibular na remoção de dentes impactados: relato de caso / Sagittal split ramus osteotomy for removal of impacted teeth: a case report

A osteotomia sagital do ramo mandibular é uma técnica cirúrgica, utilizada desde a década de 50, no tratamento de deformidades dentoesqueléticas da mandíbula. Consiste numa técnica consagrada, segura, com riscos previsíveis e prognóstico extremamente favorável, que pode ser utilizada, também, para remoção de dentes com impactação severa na região de ramo/ângulo/corpo da mandíbula. Este artigo tem como objetivo descrever um caso de uma paciente com impactação do segundo e terceiro molar inferior, a qual foi submetida à remoção pela técnica de osteotomia sagital do ramo da mandíbula. O sucesso do caso demonstra que essa é uma técnica viável como alternativa na cirurgia de dentes severamente impactados, que apresentem, por exemplo, risco de lesão do nervo alveolar inferior e fratura mandibular... (AU)

The sagittal ramus split osteotomy of the mandibular is a surgical technique used since the 50s in the treatment of deformities dentalskeletal jaw. Is a dedicated, safe technique with predictable risks and extremely favorable prognosis, which can also be used for removal of teeth with severe impaction in the ramus/angle/body of the mandible. This article aims to describe a case of a patient with impaction of the second and third molar, which was subjected to removal by sagittal ramus split osteotomy technique of the jaw. The success of the case shows that this is a viable technique as an alternative to severely impacted teeth surgery that have, for example, risk of inferior alveolar nerve injury and mandibular fracture... (AU)