Effect of miniscrew placement height on the distribution of biological forces produced by clear aligner for mandibular molar distalization / 口腔疾病防治

Objective@#To explore the effect of different miniscrew placement heights on the distribution of biological forces produced by clear aligner combined with intramaxillary traction for mandibular molar distalization, to identify the miniscrew location that is conducive to the protection of lower anterior tooth anchorage and to provide a reference that can be used when designing clinical treatments.@*Methods@#Mimics, GeomagicStudio 2017, SolidWorks 2016, and Ansys workbench were used to establish finite element analysis models and perform mechanical analysis under the following six working conditions: working condition 1 was the control group without miniscrews; working conditions 2 to 5 had miniscrew in the buccal bone cortex between the first and second molars of the lower jaw 10 mm, 7 mm, 4 mm, and 1 mm from the top of the alveolar crest, respectively; working condition 6 had the miniscrew in the center of the buccal tongue at the anterior edge of the ascending branch of the lower jaw 5 mm above the occlusal plane.@*Results@#On the sagittal axis, miniscrew anchorage caused distal displacement of all teeth. Compared to the control group, in the miniscrew group, the displacement of the anterior molars exceeded that of the second molars. On the vertical axis, the result in the control group was similar to backward bending; the results in the miniscrew groups resembled the effect of a lever, lowering the lateral incisors and canines and raising the central incisors and first premolars. On the coronal axis, the second premolars and the first molars showed lingual displacement in the control group, and only the premolars and first molars showed lingual displacementin the miniscrew groups. The canines were the teeth that were most strongly affected by the change in miniscrew placement height.@*Conclusion@#The higher the miniscrew position is, the stronger the protective effect on the anterior anchorage. According to the miniscrew placement height, the mandibular arch should be properly narrowed, the central incisors and first premolars should be lowered, and the lateral incisors and canines should be raised when designing clinical treatments.

Depth and proximity of third molars to the inferior alveolar canal in panoramic radiographs of a Latin American population

Introduction: extraction of lower third molars involve the possible occurrence of complications such as injury of the content of the Inferior Alveolar Canal. Methods: a cross-sectional study was conducted with a sample of 6488 lower molar records of digital panoramic radiographs of patients from 6 Latin American countries from 2010-2015. The variables studied were the depth of lower third molar according to the Pell and Gregory classification, and the proximity of a third molar to the Inferior Alveolar Canal that was evaluated according to the proposed classification, based on a modification of the Langlais et al classification.20 Descriptive and bivariate statistical analyses were performed. Results: in terms of the proximity, the highest frequency was Intact with 27.45%(n=1781). Regarding the depth of the lower third molar, the most frequent were the Position B with 46.90%(n=3043) and Position A with 46.75%(n=3033). The proximity and depth of the lower third molar had statistical difference according to age(p<0.01) and sex (p<0.001). The overall proximity of the lower third molar to the Inferior alveolar canal, according to depth was 37.52%(n=1766) in Position A, in Position B it was 54.51%(n=2566) and Position C was 7.97%(n=375) and had association between variables(p<0.001). Conclusions: taking into consideration the modified classification of Langlais et al.20, lower third molars are close to the Inferior Alveolar Canal, and according to the Pell and Gregory classification for the depth, the most frequent positions are A and B. In addition, proximity and depth were associated with each other, and with the co-variables country, age, and sex.

Introducción: la extracción de terceros molars inferiores implica la posible aparición de complicaciones, como la lesión del contenido del Canal Alveolar Inferior. Métodos: se realizó un estudio transversal con una muestra de 6488 registros de terceros molares inferiores de radiografías panorámicas digitales en pacientes de 6 países latinoamericanos, entre 2010-2015. Las variables fueron profundidad del tercer molar inferior según la clasificación de Pell y Gregory, y proximidad del tercer molar al Canal Alveolar Inferior, evaluada según una clasificación propuesta, basada en la clasificación modificada de Langlais et al.20 Se realizaron análisis estadísticos descriptivos y bivariados. Resultados: en la proximidad, la mayor frecuencia se presentó en Intacto con 27,45%(n=1781); en cuanto a la profundidad del tercer molar inferior, las más frecuentes fueron la Posición B con 46,90%(n=3043) y la Posición A con 46,75%(n=3033). La proximidad y profundidad del tercer molar inferior presentaron diferencias estadísticas de acuerdo con la edad (p<0,01) y sexo (p<0,001). La proximidad total del tercer molar inferior al canal alveolar inferior, según la profundidad fue de 37,52%(n=1766) en Posición A, en Posición B de 54,51%(n=2566) y Posición C de 7,97%(n=375). Además, se presentó asociación entre las variables (p<0,001). Conclusiones: considerando la clasificación modificada de Langlais et al.20, la mayoría de los terceros molares inferiores están próximos al canal alveolar inferior; y según la profundidad de Pell y Gregory, las posiciones más frecuentes son A y B. Además, la proximidad y la profundidad se asociaron entre sí, y con las co-variables país, edad y sexo.

Variation in mandible shape and size due to osteoporosis: Geometric morphometrics study

Objective: Assessing whether it is possible screening women with osteoporosis through geometric morphometrics based on panoramic x-ray. Materials and Methods: Leukoderma women, after menopause, 40 years old (or older), with confirmed medical diagnosis of presence, or absence, of osteoporosis through bone densitometry examination. (N = 62). Measurements taken through panoramic X-ray based on geometric morphometrics. All x-rays were taken twice by the same researcher. Procrustes superimposition was assessed through Cartesian coordinates generated from anatomic landmark and semilandmarks. Regression Analysis, Multivariate Analysis of Variance (MANOVA), discriminant function and cross validation analysis, and Thin plate spliness in MorphoJ software were carried out. Subsequently, Fluctuating Asymmetry Analysis (FA) was conducted and ANOVA was performed to assess differences in centroid size. Results: Significant values were recorded for mandible shape (p<0.01) through MANOVA. Significant values (P<0.01) were also found through discriminant function analysis between groups of women with, and without, osteoporosis. Fluctuating asymmetry analysis showed significant differences in mandible shape and size between sides (p<0.01). Conclusions: Geometric morphometrics proved to be effective in screening and identifying elderly leukoderma women with, or without, osteoporosis based on panoramic x-rays. This is a promising technique to diagnose or identify patients with some health condition.

Fratura de mandíbula: análise de 50 casos cirúrgicos em um hospital escola / Jaw fracture: analysis of 50 surgical cases in a teaching hospital

Introdução: A mandíbula é o maior e mais forte dos ossos da face. Em razão de sua topografia, apresenta vulnerabilidade nos traumas. A análise de dados sobre as fraturas de mandíbula se mostram fundamentais para auxiliar no tratamento e em políticas de saúde pública. O objetivo desse estudo é realizar um levantamento epidemiológico de fraturas mandibulares tratadas cirurgicamente. Método: Triagem através do sistema de informação hospitalar, buscando pacientes submetidos a cirurgia para fratura de mandíbula realizadas em um hospital escola pela equipe de cirurgia plástica, em Campinas-SP, de abril de 2015 a abril de 2020. Foram, então, coletados dados por meio da análise de prontuários. Resultados: Foram incluídos 50 pacientes, sendo 90% do sexo masculino. A média de idade foi 30,7 anos. A etiologia predominante foi acidente automotivo e a região mais fraturada na mandíbula foi a parassínfise. A mediana de tempo entre o trauma e cirurgia foi de 19 dias. Onze (22%) pacientes apresentavam alguma comorbidade. Quatorze pacientes (28%) foram internados em Unidade de Terapia Intensiva (UTI) e 42% operaram com outra especialidade além da Cirurgia Plástica. Dez (20%) pacientes apresentaram alguma complicação da cirurgia, sendo a mais comum a deiscência de ferida operatória. Conclusão: Houve predominância entre homens jovens e de acidentes de trânsito como etiologia. As fraturas foram localizadas preferencialmente na região da parassínfise e foram tratadas por meio de fixação interna rígida. Os elevados índices de internação em UTI, lesões associadas e realizações de procedimentos cirúrgicos por outras especialidades evidenciam a gravidade dos pacientes assistidos no serviço.

Introduction: The mandible is the largest and strongest of the bones in the face. Due to its topography, it is vulnerable to trauma. Data analysis on mandible fractures is fundamental for treatment and public health policies. This study aims to conduct an epidemiological survey of surgically treated mandibular fractures. Method: Screening through the hospital information system, seeking patients undergoing surgery for jaw fracture performed at a teaching hospital by the plastic surgery team in Campinas-SP from April 2015 to April 2020. Data were then collected through analysis of medical records. Results: 50 patients were included, 90% male. The average age was 30.7 years. The predominant etiology was an automobile accident, and the most fractured region in the mandible was the parasymphysis. The median time between trauma and surgery was 19 days. Eleven (22%) patients had some comorbidity. Fourteen patients (28%) were admitted to the Intensive Care Unit (ICU), and 42% underwent surgery with another specialty besides Plastic Surgery. Ten (20%) patients had some complication of the surgery, the most common being surgical wound dehiscence. Conclusion: There was a predominance among young men and traffic accidents as etiology. Fractures were preferably located in the parasymphysis region and were treated using rigid internal fixation. The high rates of ICU admission, associated injuries, and surgical procedures carried out by other specialties demonstrate the severity of the patients assisted in the service.

Sex Determination in the Contemporary Chilean Population by Mandible Analysis in Panoramic Radiographies / Estimación Sexual de la Población Chilena Contemporánea Mediante Análisis de la Mandíbula en Radiografías Panorámicas

SUMMARY: Sex identification of a deceased human individual by means of the mandible is very important for forensic dentistry. The aim of the present study was to determine the sex of Chilean individuals by mandible analysis in panoramic radiographies. Linear and angular parameters of the mandible were analyzed from panoramic radiographies (PR). The study included PR of adult Chilean individuals, of both sexes, with optimum solution and contrast, and which allowed the angles and rami of the mandible to be viewed. Sex was determined by univariate and bivariate discriminant function analysis. The sample consisted of 594 PR of individuals aged between 18 and 84 years. The best sex predictor using univariate discriminant function analysis was the mandibular ramus height (MRH) (74.1 %), followed by the distance from the mental foramen - mandibular base (DMF-MB) (69.1 %) and the bicondylar breadth (BC) (66.7 %). The parameters that presented the lowest sex prediction were the angle of the mandible (AM) with 55.0 % and the distance between mental foramina (DMF) with 53.7 %. The best sex prediction was obtained by the step model of discriminant function analysis (80.2 %), including only three parameters: MRH, BC and DMF-MB. The parameters height of the mandibular ramus, bicondylar breadth and distance from the mental foramen - base of the mandible are good predictors of sex in Chilean individuals when used in conjunction; they are therefore indicated for sex determination in the contemporary Chilean population.

La identificación humana de un individuo fallecido a través de la mandíbula es muy relevante para la odontología forense. El objetivo de este estudio fue estimar el sexo de individuos Chilenos a través del análisis de la mandíbula, utilizando radiografías panorámicas. Fueron analizados parámetros lineales y angulares de la mandíbula, a través de radiografías panorámicas (RP). Se incluyeron RP de individuos chilenos adultos, ambos sexos, con solución y contraste óptimos, y que permitían la visualización de los ángulos y ramas de la mandíbula. Se realizó análisis por función discriminante univariada y bivariada para estimación del sexo. Fueron incluidas 594 RP de individuos entre 18 y 84 años. Para el análisis de función discriminante univariado, la altura de la rama mandibular (ARM) fue el parámetro más predictivo (74,1 %), seguido de la distancia foramen mentoniano - base de la mandíbula (DFM-BM) (69,1 %) y el ancho bicondilar (ABCo) (66,7 %). Los parámetros que presentaron menor predicción sexual fueron el ángulo de la mandíbula (AM) con un 55,0 % y la distancia inter-forámenes mentonianos (DIFM), con el 53.7 %. El análisis por pasos fue el modelo de análisis de función discriminante que presentó la mayor predicción sexual (79,5 %), en el cual fueron incluidos sólo tres parámetros: ARM, ABCo y DFM-BM. Los parámetros altura de la rama de la mandíbula, ancho bicondilar y distancia desde el foramen mentoniano hasta la base de la mandíbula son buenos predictores del sexo en individuos Chilenos cuando utilizados en conjunto y están indicados para estimar el sexo en la población chilena contemporánea.

Conservative treatment of ameloblastoma: report of 2 cases and review of the literature

Introduction: ameloblastomas correspond to one of the most prevalent odontogenic tumors in developing countries, they are mainly located in the mandible, and their treatment has been widely discussed over the years, using radical or conservative treatments depending on different variables. Clinical case: we present two cases of patients with ameloblastoma who underwent conservative treatment without the use of adjuvant therapy, obtaining satisfactory results at 36 and 48 months. Discussion: due to a possible recurrence with conservative treatment, radical management has been suggested, however, the choice of treatment should be based on a series of clinical, histological, and radiographic characteristics.

Introducción: Los ameloblastomas corresponden a uno de los tumores odontogénicos más prevalentes en los países en desarrollo, se ubican principalmente en la mandíbula, y su tratamiento ha sido ampliamente discutido a lo largo de los años, utilizando tratamientos radicales o conservadores dependiendo de distintas variables. Caso clínico: se presentan dos casos de pacientes con un ameloblastoma a quienes se les realizó tratamiento conservador sin uso de terapia coadyuvante, obteniendo resultados satisfactorios a los 36 y 48 meses. Discusión: Debido a una posible recurrencia con un tratamiento conservador, se ha sugerido manejo radical, sin embargo, la elección de tratamiento debe ser en base a una serie de características clínicas, histológicas y radiográficas.

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.

CBCT study of root apices distance to mandibular canal in peruvian population

The purpose of this study was to compare the average distances from the root apices of the first molars, second molars, and second premolars to the mandibular canal according to sex in the Peruvian population using cone-beam computed tomography (CBCT). Eighty CBCT scans of Peruvian patients aged from 15-80 years were examined. After locating the mandibular canal, measurements of the vertical distances from the mandibular canal to the apices of the second premolars, as well as the first molars and second molars, were made. For the statistical analysis, Student's t test was used for both paired and unpaired samples, with a significance level of p0.05) between the distances from the apices of the second premolars and the first and second molars to the mandibular canal. However, for the second premolars and second molars on the left side, the values were higher, with averages of 5.52mm and 3.75mm, respectively. The mesial roots of the second molars were closer to the mandibular canal. In addition, women showed shorter distances than men.

El propósito de este estudio fue comparar las distancias promedio desde los ápices radiculares de primeros molares, segundos molares y segundos premolares al canal mandibular según sexo en la población peruana mediante tomografía computarizada de haz cónico (TCHC). Se examinaron 80 tomografías CBCT de pacientes peruanos con edades comprendidas entre los 15 y 80 años. Luego de ubicar el canal mandibular, se realizaron mediciones de las distancias verticales desde el canal mandibular hasta el ápice de los segundos premolares mandibulares, así como de los primeros molares y segundos molares. Para el análisis estadístico se utilizó la prueba t de Student para muestras pareadas y no pareadas con un nivel de significación de p0.05) entre las distancias desde los ápices de los segundos premolares mandibulares y los primeros y segundos molares al canal mandibular. Sin embargo, para los segundos premolares y segundos molares en el lado izquierdo, los valores fueron más altos con un promedio de 5,52mm y 3,75mm, respectivamente. Las raíces mesiales de los segundos molares estaban más cerca del canal mandibular. Además, las mujeres mostraron distancias más cortas que los hombres.

Lesión Fibro-ósea de Mandíbula: Un Hallazgo Radiográfico / Fibro-osseous Lesion of the Mandible: A Radiographic Finding

Las lesiones fibro-óseas son consideradas benignas y componen un grupo de patologías de desórdenes que se caracterizan por el reemplazo de un hueso normal por un tejido compuesto de fibras colágenas, fibroblastos y tejido mineralizado. Presentamos un hallazgo radiográfico obtenido de un paciente de sexo masculino de 41 años de edad que asiste a un centro de radiología para realizarse una radiografía panorámica, el examen revela un interesante hallazgo radiográfico en la hemi mandíbula izquierda, donde se observa una lesión fibro-ósea con expansión ósea a nivel de reborde marginal y cortical basal mandibular, desplazamiento de canal mandibular, desplazamiento dentario, compromiso de cortical alveolar y rizálisis en diferentes niveles en los dientes adyacentes a la lesión. De acuerdo a los antecedentes anteriores se establece una hipótesis diagnóstica de Fibroma Osificante de larga data debido a su radiopacidad. La Organización Mundial de la Salud lo clasifica como una neoplasia ósea benigna con afección al esqueleto craneofacial, de mayor incidencia en mandíbula, se presenta generalmente entre la 3º y 4º década de vida. Concluimos que las lesiones fibro-óseas pueden ser detectadas como un hallazgo radiográfico, esto es relevante para un tratamiento precoz, sin embargo, el diagnóstico debe realizarse complementando los antecedentes clínicos e histopatológicos de la lesión, poniendo especial atención en el diagnóstico diferencial.

Fibro-osseous lesions are considered benign and make up a group of disorder pathologies that are characterized by the replacement of normal bone by tissue composed of collagen fibers, fibroblasts, and mineralized tissue. We present a radiographic finding obtained from a 41-year-old male patient who attended a radiology center for a panoramic radiograph. The examination revealed an interesting radiographic finding in the left hemi-mandible, where a fibro-osseous lesion was observed. with bone expansion at the level of the marginal ridge and basal mandibular cortex, displacement of the mandibular canal, dental displacement, compromise of the alveolar cortex and rizalysis at different levels in the teeth adjacent to the lesion. According to the previous antecedents, a long-standing diagnostic hypothesis of Ossifying Fibroma is established due to its radiopacity. The World Health Organization classifies it as a benign bone neoplasm affecting the craniofacial skeleton, with the highest incidence in the jaw, generally presenting between the 3rd and 4th decade of life. We conclude that fibro-osseous lesions can be detected as a radiographic finding, this is relevant for early treatment, however the diagnosis must be made by complementing the clinical and histopathological history of the lesion, paying special attention to the differential diagnosis.

Peripheral squamous odontogenic tumor associated with an impacted mandibular third molar: A case report

Introduction: Squamous odontogenic tumor is a benign but locally infiltrative, epithelial odontogenic tumor. This case report presents a case of a peripheral variant of squamous odontogenic tumor. Case Presentation: A 29-year-old male patient presented with pain in the left posterior mandible region for one month. Radiographic examination revealed an impacted left mandibular third molar with no other abnormalities. Management and Prognosis: The impacted tooth was removed under local anaesthesia. Histopathological examination of the abnormally thick pericoronal tissue, covering the impacted tooth revealed islands of bland squamous epithelium in a background of mature fibrous connective tissue. The prognosis was good with no signs of recurrence after one year of follow- up. Conclusion: Squamous odontogenic tumor should be considered in the differential diagnosis of pericoronal pathoses, although it is rare in this location.

Osteonecrosis maxilar inferior asociado a bifosfonatos / Lower jaw osteonecrosis associated with bisphosphonates / Osteonecrose do maxilar inferior associada a bisfosfonatos

Introducción: dada la alta prescripción de bifosfonatos, presentamos sus efectos adversos en la esfera odontológica, siendo una complicación poco frecuente, pero de difícil tratamiento. Sin necesidad de suspender el tratamiento, dado el importante beneficio en cuanto a la prevención de fractura por fragilidad. Estas fracturas causan una alta morbimortalidad en contraposición al bajo riesgo que conlleva la Osteonecrosis mandibular asociada a bifosfonatos. Objetivo: orientar al personal de salud que maneja estos fármacos y quien asiste dichas complicaciones a poseer conocimientos para la prevención de osteonecrosis. Identificar y diferenciar los pacientes con mayor riesgo, de acuerdo con la dosis de bifosfonatos y la frecuencia del tratamiento. Materiales y Método: se realizó una revisión bibliográfica en las siguientes fuentes: Scielo, Google académico, Medline/Pubmed, Biblioteca Virtual en Salud (Brasil), desde el año 2005 a la fecha, idiomas español, portugués e inglés. Los descriptores utilizados son bifosfonatos, mandíbula, maxilar, odontología, osteonecrosis, osteonecrosis de los maxilares asociada a bifosfonatos. Resultados: las últimas pautas de tratamiento fueron modificadas en 2014, por consenso de la Asociación Americana de cirugía Oral y Maxilofacial. La patogénesis de la osteonecrosis maxilar asociada a bifosfonatos no está completamente definida, aunque las publicaciones tratan de explicarla. El riesgo de desarrollarla por terapia oral es menor que por su administración vía intravenosa. Discusión: el médico que prescribe el antirresortivo debe conocer el estado de salud dental de su paciente y, en lo posible, remitirlo a examen con el odontólogo antes de iniciar la terapia con bifosfonatos.

Introduction: Given the high prescription of bisphosphonates, we present their adverse effects in the dental sphere, being an infrequent complication, but difficult to treat. There is no need to suspend treatment, given the important benefit in terms of prevention of fragility fractures. These fractures cause high morbimortality as opposed to the low risk associated with bisphosphonate-associated osteonecrosis of the jaw. Objective: To orient the health personnel who handle these drugs and who assist these complications to have knowledge for the prevention of osteonecrosis. To identify and differentiate patients at higher risk, according to the dose of bisphosphonates and frequency of treatment. Materials and Method: A literature review was performed in the following sources: Scielo, Google academic, Medline/Pubmed, Virtual Health Library (Brazil), from 2005 to date, Spanish, Portuguese and English languages. The descriptors used were bisphosphonates, mandible, maxilla, dentistry, osteonecrosis, osteonecrosis of the jaws associated with bisphosphonates. Results: The latest treatment guidelines were modified in 2014, by consensus of the American Association of Oral and Maxillofacial Surgery. The pathogenesis of bisphosphonate-associated maxillary osteonecrosis is not completely defined, although publications try to explain it. The risk of developing it by oral therapy is lower than by intravenous administration. Discussion: The physician who prescribes the antiresorptive drug should know the dental health status of his patient and, if possible, refer him for examination by a dentist before initiating bisphosphonate therapy.

Introdução: dada a alta prescrição de bisfosfonatos, apresentamos seus efeitos adversos na esfera odontológica, uma complicação rara, mas de difícil tratamento. Sem a necessidade de suspender o tratamento, dado o importante benefício em termos de prevenção de fraturas por fragilidade. Essas fraturas causam alta morbidade e mortalidade, em contraste com o baixo risco associado à osteonecrose da mandíbula associada aos bisfosfonatos. Objetivo: orientar a equipe de saúde que manipula esses medicamentos e que atende a essas complicações para que tenham conhecimento sobre a prevenção da osteonecrose. Identificar e diferenciar os pacientes de maior risco, de acordo com a dose de bisfosfonatos e a frequência do tratamento. Materiais e Método: foi realizada uma revisão da literatura nas seguintes fontes: Scielo, Google acadêmico, Medline/Pubmed, Biblioteca Virtual em Saúde (Brasil), de 2005 até a presente data, idiomas espanhol, português e inglês. Os descritores utilizados foram: bisfosfonatos, mandíbula, maxila, odontologia, osteonecrose, osteonecrose dos maxilares associada a bisfosfonatos. Resultados: as diretrizes de tratamento mais recentes foram modificadas em 2014, por consenso da Associação Americana de Cirurgia Oral e Maxilofacial. A patogênese da osteonecrose da mandíbula associada a bisfosfonatos não está totalmente definida, embora a literatura tente explicá-la. O risco de desenvolvê-la com a terapia oral é menor do que com a administração intravenosa. Discussão: o médico que prescreve o medicamento deve estar ciente do estado de saúde bucal do paciente e, se possível, encaminhar o paciente para ser examinado por um dentista antes de iniciar a terapia com bisfosfonatos.

Tomographic evaluation of mandibular buccal shelf in patients with different vertical growth pattern / Evaluación de la placa ósea mandibular en pacientes con diferente patrón de crecimiento vertical

The purpose of this research was the tomographic evaluation of the Mandibular Buccal Shelf (MBS) in orthodontic patients with different vertical growth pattern. An observational, descriptive, cross-sectional and retrospective study was conducted. Tomographic images of patients aged 14 to 40 years were observed and a database was formed with those that met the inclusion criteria. The sample size was 10 for each group according to vertical growth pattern (hypodivergent, normodivergent and hyperdivergent). Then four zones of frequent insertion of extralveolar mini-screws were selected in the MBS, taking as a reference the mesial and distal roots of the first and second mandibular molar. When comparing the characteristics of MBS between vertical growth patterns, between sexes and hemiarchs, no statistically significant differences were found. However, when the characteristics of MBS were compared according to the reference root, it was found that there were statistically significant differences. The vestibular area to the distal root of the second mandibular molar presented the highest values in terms of angulation, height and thickness. There are no significant differences in the bone characteristics of MBS according to vertical growth patterns, sexes or hemiarchs. Angulation, height and thickness progressively increase from the vestibular bone of the mesial root of the first mandibular molar to the distal root of the second molar.

El propósito de esta investigación fue la evaluación tomográfica de la placa ósea mandibular (POM) en pacientes de ortodoncia con diferente patrón de crecimiento vertical. Se realizó un estudio de tipo observacional, descriptivo, transversal y retrospectivo. Se observó imágenes tomográficas de pacientes de 14 a 40 años de edad y se formó una base de datos con las que cumplían los criterios de selección. El tamaño de muestra fue de 10 para cada grupo según patrón de crecimiento vertical (hipodivergentes, normodivergentes e hiperdivergentes). Luego se seleccionaron cuatro zonas de inserción frecuente de minitornillos extralveolares en la POM, tomando como referencia las raíces mesial y distal del primer y segundo molar mandibular. Al realizar la comparación de las características de la POM entre patrones de crecimiento vertical, entre sexos y hemiarcadas no se encontraron diferencias estadísticamente significativas. Sin embargo, cuando se comparó las características de la POM según la raíz de referencia se encontró que había diferencias estadísticamente significativas. La zona vestibular a la raíz distal de la segunda molar mandibular presento los mayores valores en cuanto angulación, altura y grosor. No existen diferencias significativas en las características óseas de la POM según patrones de crecimiento vertical, sexos o hemiarcadas. La angulación, la altura y el grosor aumenta progresivamente desde el hueso vestibular de la raíz mesial del primer molar mandibular hacia la raíz distal del segundo molar.

Frecuencia de la cavidad ósea de Stafne. Un análisis retrospectivo en radiografías panorámicas / Frequency of Stafne's bone cavity. A retrospective analysis in panoramic radiographs

Introducción: La cavidad ósea de Stafne es una variante anatómica poco frecuente, radiolúcida y bien delimitada, que usualmente se presenta en la región molar cerca del ángulo mandibular y por debajo del canal para el nervio dentario inferior. Es frecuente que sea erróneamente diagnosticada con otras entidades de carácter patológico. Objetivo: Determinar la frecuencia de la cavidad ósea de Stafne en las radiografías panorámicas del Servicio de Radiología Oral y Maxilofacial del Centro Dental Docente "Cayetano Heredia", desde 2015 hasta 2019. Métodos: Se realizó un estudio observacional, descriptivo, transversal y retrospectivo de una muestra de 17875 radiografías panorámicas. Se consideraron las variables demográficas como el sexo, la edad, la localización y la forma, posteriormente se realizaron tablas de contenido para el análisis de los datos. Resultados: Entre los 17875 pacientes, solo 24 (0,13 por ciento) presentaban cavidad ósea de Stafne, incluidos 16 hombres y 8 mujeres. La octava década de vida presentó la mayor cantidad de casos con 6 (0,4 por ciento). La localización posterior derecha contó con 13 (54,17 por ciento), la posterior izquierda con 7 (29,17 por ciento) y la anterior con 4 (16,67 por ciento). La forma ovalada con 23 (95,83 por ciento) y la redonda solo con 1 (4,17 por ciento). Conclusiones: La frecuencia de la cavidad ósea de Stafne fue de 0,13 por ciento con predilección del sexo masculino, la octava década de vida, la localización posterior derecha y la forma ovalada(AU)

Introduction: Stafne's bone cavity is a rare, radiolucent, well-demarcated anatomic variant that usually occurs in the molar region near the mandibular angle and below the canal for the inferior dental nerve. It is frequently misdiagnosed with other pathological entities. Objective: To determine the frequency of Stafne's bone cavity in panoramic radiographs of the Oral and Maxillofacial Radiology Service of the Teaching Dental Care Center "Cayetano Heredia", from 2015 to 2019. Methods: An observational, descriptive, cross-sectional and retrospective study was performed on a sample of 17875 panoramic radiographs. Demographic variables such as gender, age, location and shape were considered; subsequently tables of contents were performed for data analysis. Results: Among the 17875 patients, only 24 (0.13 percent) had Stafne's bone cavity, including 16 males and 8 females. The eighth decade of life presented the highest number of cases with 6 (0.4 percent). The right posterior location accounted for 13 (54.17 percent), the left posterior with 7 (29.17 percent) and the anterior with 4 (16.67 percent). The oval shape with 23 (95.83 percent) and round with only 1 (4.17 percent). Conclusions: The frequency of Stafne's bone cavity was 0.13 percent with male sex predilection, eighth decade of life, right posterior location and oval shape(AU)

Obesity influences the development of bisphosphonate-induced osteonecrosis in Wistar rats

Abstract Medication-related osteonecrosis of the jaw (MRONJ) is characterized by bone exposure for more than eight weeks in patients who have used or been treated with antiresorptive or antiangiogenic drugs, without a history of radiation therapy or metastatic diseases in the jaws. Obesity is associated with changes in periodontal tissues and oral microbiota that are linked to bone alterations. This study aimed to analyze the influence of obesity on the development of bisphosphonate-induced osteonecrosis. The experiment randomly and simply divided 24 male Wistar rats (Rattus norvegicus) into four groups: healthy, with osteonecrosis, obese, and obese with osteonecrosis (n=6 per group). Osteonecrosis was induced through weekly intraperitoneal injection for eight weeks at a dose of 250 µg/kg of zoledronic acid in a 4 mg/5 mL solution, combined with trauma (exodontia). Obesity was induced through a high glycaemic index diet. Each group was qualitatively and quantitatively evaluated regarding the development of models and pathological anatomy of the lesions. The results were expressed in mean percentage and standard deviation and statistically analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post-hoc test, with a significance level of 5% (p<0.05) to establish differences found between the groups. Animals in the osteonecrosis group and the obese with osteonecrosis group presented larger necrosis areas (averages: 172.83±18,19 µm2 and 290.33±15,77 µm2, respectively) (p<0,0001). Bone sequestration, hepatic steatosis, and increased adipocyte size were observed in the obese group (average: 97.75±1.91 µm2) and in the obese with osteonecrosis group (average: 98.41±1.56 µm2), indicating greater tissue damage in these groups (p<0,0001). All parameters analyzed (through histological, morphometric, and murinometric analyses) increased for the obese and obese with osteonecrosis groups, suggesting a possible influence of obesity on the results. However, further studies are needed to confirm the role of obesity in the possible exacerbation of osteonecrosis and understand the underlying mechanisms.

Position of lingual foramina in cone beam computed tomography and its implications for choosing the dimensions of dental implants for mandibular symphysis / Posição das foraminas linguais na tomografia computadorizada de feixe cônico e suas implicações na escolha das dimensões dos implantes dentários para sínfise mandibular

ABSTRACT Objective: To identify the lingual foramina in a Brazilian population of 210 individuals through Cone-Beam Computed Tomography images, in order to guide the installation of dental implants in the region of the mental symphysis. Methods: After identifying the lingual foramina on a parasagittal section, four measurements were taken: distance to the alveolar ridge, distance to the mandibular lower border, distance to the limit of the vestibular cortical, and alveolar ridge inclination angle. The measurements were compared in relation to gender by the Mann-Whitney test. The association between gender and the number of foramina was done by the chi-square test. Pearson's correlation analyzed the linear relationship between age and number of foramina. Results: Lingual foramina are present in 99.6% of the research participants. In the upper-inferior direction, a mean distance to the alveolar ridge of 21.4 mm was noted, while the mean distance to the lower mandibular border was 13.1 mm. In the bucco-lingual direction, a mean distance from the lingual foramina to the vestibular cortical of 15.2 mm is noted. The inclination angle of the alveolar ridge had a mean of 25.4º. Regarding gender, the test was not significant only for the distance to the vestibular cortical. Conclusion: The lingual foramina had a descending way in 100% of cases, being positioned mainly in the middle thirds (66.5%) and lower thirds (32.7%) of the mandibular ridge height. The use of dental implants up to 13 mm in length and up to 4 mm in diameter in the region of the symphysis mentualis is recommended.

RESUMO Objetivos: Identificar as foraminas linguais em uma população brasileira de 210 indivíduos, por meio de imagens de tomografia computadorizada de feixe cônico, a fim de orientar a instalação de implantes dentários em região de sínfise mentual. Métodos: Após identificação das foraminas linguais em corte parasagital, foram realizadas quatro medidas: distância até à crista alveolar, distância até à borda inferior da mandíbula, distância até o limite da cortical vestibular e ângulo de inclinação do rebordo alveolar. As medidas foram comparadas em relação ao sexo pelo teste Mann-Whitney. A comparação entre os sexos e o número de foraminas foi feito pelo teste qui-quadrado. A correlação de Pearson analisou a relação linear entre idade e número de foraminas. Resultados: As foraminas linguais estão presentes em 99,6% dos indivíduos. No sentido súpero-inferior, nota-se uma distância média até à crista alveolar de 21,4 mm, enquanto a distância média até à borda inferior da mandíbula foi de 13,1 mm. No sentido vestíbulo-lingual, nota-se uma distância média da foramina lingual até a cortical vestibular de 15,2 mm. O ângulo de inclinação do rebordo alveolar apresentou uma média de 25,4º. Em relação ao sexo, o teste só não foi significativo para a distância até a cortical vestibular. Conclusão: As foraminas linguais apresentam um trajeto descendente em 100% dos casos, posicionando-se, principalmente, nos terços médios (66,5%) e terços inferiores (32,7%) da altura do rebordo mandibular. Recomenda-se o uso de implantes dentários de até 13 mm de comprimento e de até 4mm de diâmetro em região de sínfise mentual.

Marginal versus Segmental Mandibulectomy in the Treatment of Oral Cavity Cancer: A Systematic Review and Meta-analysis

Abstract Introduction Oral cavity squamous cell carcinoma (OCSCC) is the most common malignancy in the oral cavity. Two types of mandibular resections have been described: the segmental mandibulectomy and the marginal mandibulectomy. Both may have a different impact over the quality of life, oncological prognosis, and functional or aesthetic result. Objectives The aim of this study was to systematically explore the literature to determine the survival outcomes and disease control rates in patients who underwent segmental or marginal mandibulectomy for OCSCC with histological evidence of cortical and medullary bone invasion. Data Synthesis This review involved a systematic search of the electronic databases MEDLINE/PUBMED, Google Scholar, Ovid Medline, Embase, and Scopus including articles from 1985 to 2019. Fifteen articles were included for qualitative analysis and 11 articles were considered for meta-analysis calculations. All of them correspond to retrospective cohort studies. Conclusion This systematic review reveals the low-level evidence regarding the impact over local control or survival according to the type of mandibulectomy. Our results need to be considered with precaution according to the limited evidence available. We just found difference regarding the 5-year disease-free survival, and a tendency in favor of segmental mandibulectomy was confirmed when medullary invasion was evident.

Imaging study on the relationship between anterior and posterior occlusal planes and temporomandibular osteoarthrosis / 华西口腔医学杂志

OBJECTIVES@#The aim of this study was to compare the anterior and posterior occlusal plane characteristics of patients with different temporomandibular joint osseous statuses.@*METHODS@#A total of 306 patients with initial cone beam CT (CBCT) and cephalograms were included. They were divided into three groups on the basis of their temporomandibular joint osseous status: bilateral normal (BN) group, indeterminate for osteoarthrosis (I) group, and osteoarthrosis (OA) group. The anterior and posterior occlusal planes (AOP and POP) of the different groups were compared. Then, the regression equation was established after adjusting for confounding factors, and a correlation analysis between the occlusion planes and other parameters was performed.@*RESULTS@#SNA, SNB, FMA, SN-MP, Ar-Go, and S-Go were correlated with the occlusal planes. Relative to the BN and I groups, the FH-OP of the OA group increased by 1.67° on the average, FH-POP increased by 1.42° on the average, and FH-AOP increased by 2.05° on the average.@*CONCLUSIONS@#The occlusal planes were steeper in the patients with temporomandibular osteoarthrosis than in the patients without it, and the mandible rotated downward and backward. The height of the mandibular ramus, the mandibular body length, and the posterior face height were small. In clinical practice, attention should be given to the potential risk of temporomandibular joint osteoarthrosis in such patients. In addition, SNB, FMA, SN-MP, Ar-Go, S-Go, and occlusal planes had moderate correlations.

Efficacy of W-genioplasty on the broad and short chin / 中华医学美学美容杂志

Objective:To investigate the clinical effect of W-shaped genioplasty in the correction of broad and short chin deformity.Methods:Thirty-eight patients (5 males, 33 females, aged 20 to 41 years, mean 27.3 years) complained with broad and short chin were admitted to the Affiliated Friendship Plastic Surgery Hospitalof Nanjing Medical University from January 2019 to December 2021. CBCT scan and three-dimensional reconstruction were performed to design osteotomy line and determine the distance of chin lengthening, narrowing and advancing or retrocession preoperatively. Under general anesthesia, the W-shaped osteotomy was performed using an intraoral incision, and the angle between the bilateral free bone fragments, the distance of downward and forward movement were adjusted to change the curvature, width, length and prominence of the lower edge of the chin according to the preoperative designs. The results were evaluated by clinical appearances and image analyses at a follow-up of 3-24 months.Results:The amount of vertical lengthening of the chin in 38 cases were 2 mm to 5 mm, with an average of 3.02 mm. The horizontal narrowing width distances were 3-7 mm, with an average of 5.6 mm. The patients were followed up for 3-24 months, with an average of 10.6 months. There were no complications such as hematoma, wound dehiscence, accidental fracture, surgical area infection and permanent neurosensory disorder. 38 patients had transient sensory loss in the lower lip region of varying degrees, but all recovered spontaneously during routine follow-up period. All patients were satisfied with the improvement of facial contour.Conclusions:W-shaped geinoplasty preserves the central bone of the chin and the attachment of genioglossus muscle, which does not affect the normal anatomy and physiological function of the oral cavity. After osteotomy, the bone is removed and the bilateral bone fragments move flexibly. It can effectively change the radian, width, length and protrusion of the lower edge of the chin in three dimensions, so as to correct the wide and short deformity of the chin.

Simultaneous innervated and vascularized iliac bone flap for reconstructing mandible and nerve defects / 口腔疾病防治

@#The functional reconstruction of large maxillofacial defects is a major issue in oral and maxillofacial surgery, and autologous bone transplantation is the main method. However, bone is readily absorbed following an autologous bone transplant. Even with vascular anastomosis, spontaneous osteoporosis of transplanted bone is still serious, which affects dental implantation and functional recovery. Therefore, osteoporosis of the grafted bone has become one of the main complications of jaw reconstruction, and there is no preventive measure. The problem that autologous bone with sufficient blood supply cannot avoid osteoporosis suggests that systemic factors such as nerves, which have been neglected in traditional methods, may regulate the internal environment of the transplanted bone. Based on previous studies on the regulation of mesenchymal stem cells by the neural microenvironment, we initiated a new surgical procedure for innervated and vascularized iliac bone flaps based on animal model and cadaver studies. In the innervated and vascularized iliac bone flap, vascular microanastomosis was performed in conjunction with microneuronal anastomosis between the simultaneously harvested ilioinguinal nerve (which innervates the iliac bone and is usually sacrificed and neglected in the conventional vascularized iliac bone flap) and the inferior alveolar nerve proximally and with the mental nerve distally. By conducting clinical retrospective studies and prospective randomized controlled trials, we proved that the novel method of simultaneous innervated iliac bone transplantation can not only prevent bone resorption but also restore the sensation of adjacent soft tissues such as the lip. This may solve the key problems of sensory loss and osteoporosis after mandibular reconstruction, ensure the success of dental implant dentures, and put forward the new concept of "blood supply + innervation" bi-system bone transplantation.

Molecular mechanisms of tooth, maxilla and mandible development / 口腔医学

@#Understanding the pattern and molecular mechanisms of tooth, maxilla and mandible development is the prerequisite for studying their regeneration. Tooth development can be divided into three stages: bud-bell stage, tooth crown development stage and tooth root development stage. During these processes, key genes show spatial and temporal expression pattern. Tooth development is a complex process involving interactions between dental epithelium and mesenchyme, precise regulations of enamel knots in cusp patterning, as well as successful eruption into the oral cavity under proper biomechanical stress and signaling transductions. The development of tooth, maxilla and mandible, all of which originate from the first branchial arch, is independent and regulates each other to form a whole during development. Any developmental defects of them will ultimately cause defects to the others. In this paper, we briefly reviewed the development of tooth, maxilla and mandible, proposed that the homeostasis of microenvironment is critical for their development. Moreover, we reviewed the role of Meckel’s cartilage, a special structure and signaling mechanism during mandible development. At last, we proposed an integrated development model of tooth, maxilla and mandible. We also hope that the regeneration of fully functional tooth, maxilla and mandible in human can be achieved based on fundamental knowledge we have gained so far.