Optimal microimplant sites in the mandibular retromolar area: mesh analysis of cortical bone thickness and density in CBCT images / Sitios de microimplantes óptimos en el área retromolar mandibular: análisis de malla del grosor y densidad del hueso cortical en imágenes CBCT

SUMMARY: This study was performed to identify optimal microimplant sites in the mandibular retromolar area by measurement and analysis of cortical bone thickness and density. Forty-nine records of cone-beam computed tomography were selected from 173 patients. Invivo 5.2 software was used to measure the thickness and density of 25 sites on a mesh in the mandibular retromolar area. Pearson correlation, Spearman correlation, and binary logistic regression analyses were performed to explore correlations between retromolar measurements and patient characteristics. The LSD test was used to identify optimal microimplant sites in this area. One-way ANOVA, with post hoc SNK test, was used to compare optimal microimplant sites among the retromolar area, the distobuccal bone of the second molar, and a location between the first and second molars. The mean thickness and density of mandibular retromolar cortical bone were 2.35 ± 0.76 mm and 530.49 ± 188.83 HU, respectively. In the mandibular retromolar area, the thickness and density of cortical bone increased from the lingual to buccal sides, and from the distal to mesial. Among 25 sites, S5C1 had the greatest thickness and density; it exhibited greater thickness and density, compared with the distobuccal bone of the second molar and the site between the first and second molars. For distal uprighting of mesially tipped molars, we recommend placement of microimplants into the retromolar distobuccal site; for distalization of mandibular dentition, we recommend placement of microimplants into the retromolar mesiobuccal site (S5C1) or 2 mm from the mesial direction of the second molar distobuccal site (B).

RESUMEN: Este estudio se realizó para identificar los sitios óptimos de microimplantes en el área retromolar mandibular mediante la medición y el análisis del grosor y la densidad del hueso cortical. Se seleccionaron 49 registros de tomografía computarizada de haz cónico de 173 pacientes. Se utilizó el software Invivo 5.2 para medir el grosor y la densidad de 25 sitios en una malla en el área retromolar mandibular. Se realizaron análisis de correlación de Pearson, correlación de Spearman y regresión logística binaria para explorar las correlaciones entre las mediciones retromolares y las características del paciente. La prueba de LSD se utilizó para identificar los sitios óptimos de microimplantes en esta área. Se utilizó ANOVA unidireccional, con prueba SNK post hoc, para comparar los sitios óptimos de microimplante entre el área retromolar, el hueso distobucal del segundo molar y una ubicación entre el primer y el segundo molar. El grosor y la densidad medios del hueso cortical retromolar mandibular fueron 2,35 ± 0,76 mm y 530,49 ± 188,83 HU, respectivamente. En el área retromolar mandibular, el grosor y la densidad del hueso cortical aumentaron desde el lado lingual al bucal y desde el distal al mesial. Entre los 25 sitios, S5C1 se determinó el mayor espesor y densidad; presentó mayor grosor y densidad, en comparación con el hueso distobucal del segundo molar y el sitio entre el primero y el segundo molar. Para rectificación distal de molares con punta mesial, recomendamos la colocación de microimplantes en el sitio retromolar bucal; para la distalización de la dentición mandibular, recomendamos la colocación de microimplantes en el sitio retromolar mesiobucal (S5C1) o 2 mm desde la dirección mesial del sitio distobucal del segundo molar (B).

Morphological Study of Accessory Foramina in Dry Mandible and Its Clinical Significance

Background: To provide anatomical information on theposition and incidence of accessory foramina in mandible asthey are important for dental surgeons and anesthetists inachieving complete nerve blocks and for avoiding injury toneurovascular structures passing through them.Objective: To study the incidence of accessory foramina in drymandible in population of Bihar & compare it with incidenceamong various races of the world.Materials & Methods: Present study is a cross sectional studywhich has been carried out on 56 dried fully ossified adulthuman mandibles, which were examined in the Department ofAnatomy and Forensic Medicine of Indira Gandhi Institute ofMedical Sciences, Patna, Bihar. The age of the bones used inthe study was not predetermined. Only fully ossified dried,macerated and thoroughly cleaned mandibles which werecomplete in all respects, in order to give the correctobservations, were included in the study while the mandibleshaving any deformity or pathology were excluded. Theaccessory foramina and their positions were observed.Results: Accessory mandibular foramina were found in 55.36%, accessory mental in 23.22 %, and retromolar in 17.85% ofthe cases. The accessory foramen observed most commonly inright side (39.28%) followed by bilateral (37.5%) then left side(19.65%).Conclusion: The anatomical variability of incidence andposition of accessory foramina should be considered as theymay be used to give additional locoregional anesthesia in caseof failed mandibular blocks. Knowledge of the commonestpositions will be beneficial for oncologists and oromaxillofacialsurgeons in planning graft implants.

Modificaciones del espacio óseo posterior para terceros molares desde la infancia hasta la adolescencia / Modifications of the posterior bony space for third molars from childhood to adolescence

Introducción: Del crecimiento de los maxilares depende en gran medida la correcta disposición de los dientes, especialmente de los terceros molares, que son los últimos en brotar. Objetivo: Estimar los cambios en el espacio óseo posterior según la edad y su relación con variables epidemiológicas. Métodos: Se realizó un estudio observacional, descriptivo y transversal en niños pertenecientes al Policlínico Docente "José Martí Pérez" de Santiago de Cuba, de mayo de 2016 a febrero de 2017, para lo cual se utilizaron radiografías panorámicas en las mediciones, analizadas según las variables edad, sexo y color de la piel. Resultados: Sobresalió que la diferencia del espacio óseo posterior de la infancia a la adolescencia fue de 9 mm para el molar 18, de 8,1 para el 28, de 12,5 para el 38 y de 11,5 para el 48; no se observaron diferencias significativas en cuanto a sexo y color de la piel. Conclusiones: Con la evaluación de la magnitud dimensional de dicho espacio es posible predecir el crecimiento de los maxilares para dar ubicación a los terceros molares en el transcurso de la infancia a la adolescencia.

Introduction: The correct disposition of teeth depends in great measure on the growth of maxillary, especially the third molars that are the last ones in eruption. Objective: To estimate the changes in the posterior bony space according to age and its relationship with epidemic variables. Methods: An observational, descriptive and cross-sectional study was carried out in children belonging to José Martí Pérez Teaching Polyclinic in Santiago de Cuba, from May, 2016 to February, 2017, for which panoramic X-rays were used in the measures, analyzed according to age, sex and color of the skin. Results: It was remarkable that the difference of the posterior bony space from childhood to adolescence was 9 mm for 18 molar, of 8.1 for 28 molar, of 12.5 for 38 molar and of 11.5 for 48 molar; significant differences were not observed between sex and color of the skin. Conclusions: With the evaluation of the dimensional magnitude of this space it is possible to predict the growth of the maxillary to give location to the third molars during the course from the childhood to the adolescence.

Características anatomorradiográficas de los terceros molares en adolescentes de la enseñanza preuniversitaria / Anatomo-radiographic characteristics of third molars in senior high school students

RESUMEN Introducción: Las retenciones dentarias afectan al 17 % de los pacientes a nivel mundial y están consideradas actualmente como un síndrome, en que los terceros molares ocupan el primer lugar y cuya extirpación quirúrgica deviene la intervención más comúnmente practicada por los cirujanos maxilofaciales. Objetivo: Describir las características anatomorradiográficas de los terceros molares, así como su posible relación con variables epidemiológicas de interés. Métodos: Se realizó un estudio observacional, descriptivo y transversal en escolares del Instituto Preuniversitario "Antonio Alomá Serrano", perteneciente al área de salud del Policlínico Docente Asistencial "José Martí" de Santiago de Cuba, durante el período comprendido desde mayo de 2016 hasta febrero de 2017. Se utilizaron radiografías panorámicas indicadas a estos pacientes, en las que se efectuaron el análisis y la clasificación. Resultados: La mayoría de los dientes se encontraban en clase I (52,6 por ciento), clase C (51,9 por ciento), posición C (82,2 por ciento), verticales (47,7 por ciento) y sin aproximación sinusal (89,5 por ciento). Además se observaron relaciones significativas entre la edad y el color de la piel con respecto al espacio retromolar y la inclinación dentaria de este grupo molar, y entre el sexo y la inclinación. Conclusiones: Los terceros molares son los dientes con mayor variabilidad en cuanto a posición e inclinación intraósea y en edades avanzadas se logra suficiente espacio retromolar y verticalización en la mayoría de ellos(AU)

ABSTRACT Introduction: Tooth impaction affects 17 % of patients worldwide. It is currently considered to be a syndrome in which third molars occupy the first place. Surgical removal is the most common intervention performed by maxillofacial surgeons. Objective: Describe the anatomo-radiographic characteristics of third molars and their possible relationship to epidemiological variables of interest. Methods: A cross-sectional observational descriptive study was conducted of students from Antonio Alomá Serrano Senior High School, from the health area of José Martí University Polyclinic in Santiago de Cuba, from May 2016 to February 2017. The study was based on panoramic radiographs, which were analyzed and classified. Results: Most teeth were class I (52.6 percent), class C (51.9 percent), position C (82.2 percent), vertical (47.7 percent) and without sinus approach (89.5 percent). Significant relationships were found between age and skin color with respect to retromolar space and tooth inclination of this molar group, and between sex and inclination. Conclusions: Third molars are the teeth showing the greatest variability in terms of intraosseous inclination and position. In advanced ages most of them achieve enough retromolar space and verticalization(AU)

Study Of Distribution Of Various Accessory Foramina In 100 Human Mandibles Of South India

Introduction: Any unnamed opening is termed as Accessory foramen. Mandible being the strongest bone of theskull is pervaded by many accessory foramina other than mandibular and mental foramen. In the present studyaccessory mandibular, mental, retromolar and lingual foramina are distinguished and clinical implications arediscussed. The presence of such foramina if not identified during clinical practice may cause complications.Hence our study is done to find out the incidence and distribution of various accessory foramina of mandibleamong South Indians.Materials and Methods: The study was done on 100 adult dry human mandibles of South Indian origin obtainedfrom first MBBS students. The location and distribution of various accessory foramina were carefully observed,noted and tabulated.Results: Accessory foramen was found in 93% of mandibles. Accessory lingual foramen was found in 93 mandibles,with supraspinous foramen in 84%, accessory mandibular foramen in 34%, accessory mental foramen in 12%and retromolar foramen in 6%.Conclusion: Presence of accessory foramina may cause failure of anaesthesia during inferior alveolar nerveblock and haemorrhage during mandibular reconstruction surgeries owing to the neurovascular structurespassing through these accessory foramina. The clinicians should be aware about the presence of such accessoryforamina during the procedures.

Comprehensive understandings in the shape of retromolar pad and its classification based on clinical application

Retromolar pad is one of anatomical landmarks to use clinically for determining of specific occlusal plane level in edentulous patients and is inherently a soft tissue mass; located at the distal end of mandible and should be covered with denture. The shapes of retromolar pad show variability because it might be inevitable to be resultant forms from healing and remodeling process after the extraction of last molars. Considerations would be focused on those resultant shapes and classification with anatomical relationships and clinical significances.

A Study Of Retromolar Foramen/canal In North Indian Population

The Retromolar foramen/canal are one of the non-metric variants of the mandible located in the retromolarfossa of the mandible behind the 3rd molar of mandible. These are obviously of profound dental and surgicalimportance. The aim of the study was to know the prevalence of retromolar canal/foramen in north Indianpopulation. In the present study, 35 dry mandibles of unknown sex of north Indian origin were examined bynaked eyes to know the incidence of retromolar foramen/canal. The retromolar foramen/canal was found in 6mandibles (17.14%), bilaterally in 2 mandibles and unilaterally in 4 mandibles. We conclude that retromolarforamen /canal is of profound clinical importance.

Investigation of the prevalence of retromolar canals: a cone beam CT study / Investigación de la prevalencia de los canales retromolares: estudio de tomografía computarizada de haz cónico

SUMMARY: The retromolar canal (RMC) is a collateral branch of the mandibular canal. This branch seems to be involved in the innervation of the third molar, retromolar trigon and part of the buccal mucosa and fibres of the buccinator and temporalis muscles. The prevalence of RMC in osseous and CBCT studies was reported between 1.7 %-72 %. This study aims to investigate the prevalence of RMCs in a Turkish population using cone beam CT. 340 CBCT images of hemimandibles of 170 patients, with a mean age of 37 (range, 16-80), that clearly identified the course of the mandibular canal in the posterior mandible were selected retrospectively from the archived records of our Oral and Maxillofacial Radiology Department. The sagittal, coronal, axial and pseudopanoramic images were used for assessing the RMCs. This variant was found in 19 out of 170 patients (11 %). Of the 340 CBCT examinations in 170 patients, 20 showed the presence of a RMC (5 %). It was present unilaterally in 18 patients (95 %) and bilaterally in one patient (5 %). There was no difference in the presence of RMCs with regard to sex and sides of the mandible (p>0.05). Clinicans should be aware of RMC and this anatomical variance should be taken into consideration while planning surgery around this region. When there is any suspicion of the RMC presence CBCT is the best imaging modality to visualize the three-dimensional structure of this variant.

RESUMEN: El canal retromolar (CRM) es una rama colateral del canal mandibular. Esta rama parece estar comprometida en la inervación del tercer molar, el trígono retromolar parte de la mucosa oral y de las fibras de los músculos buccinador y temporal. La prevalencia de CRM se ha reportado entre el 1,7 % -72 % en estudios óseos y de tomografía computarizada. Este estudio tuvo como objetivo investigar la prevalencia de CRM en una población turca utilizando tomografía de haz de cono. Se seleccionaron 340 imágenes TCHC de los registros de nuestro Departamento de Radiología Oral y Maxilofacial, de mandíbulas de 170 pacientes con una edad media de 37 años (rango, 16-80), las que identificaban el trayecto del conducto mandibular en la parte posterior de la mandíbula. Se utilizaron las imágenes sagital, coronal, axial y pseudo panorámica para evaluar los CRM. La variante se encontró en 19 de los 170 pacientes (11 %). De los 340 exámenes realizados con TCHC en 170 pacientes, en 20 de éstos se observó la presencia de un CRM (5 %); se observó unilateralmente en 18 pacientes (95 %) y bilateralmente en un paciente (5 %). No hubo diferencias en la presencia de CRM con respecto al sexo y los lados de la mandíbula (p> 0,05). Los clínicos deben considerar el CRM y tener en cuenta esta variación anatómica al planificar la cirugía en esta región. Cuando existe alguna sospecha de la presencia CRM, la TCHC es la mejor modalidad para visualizar la estructura tridimensional de esta variante.

Tumor resection from retromolar trigone, posterolateral maxilla, and anterior mandibular ramus using lower cheek flap approach: a case report and review of literature

A surgical approach involving the retromolar trigone, posterolateral maxilla, and pterygoid region is the most challenging in the field of maxillofacial surgery. The upper cheek flap (Weber-Ferguson incision) with subciliary extension and the maxillary swing approach have been considered as alternatives; however, neither approach provides sufficient exposure of the pterygoid region and the anterior portion of the mandibular ramus. In this report, we describe two cases in which a lower cheek flap approach was used for complete tumor resection in the retromolar trigone and the anterior mandibular ramus. This approach allows full exposure of the posterolateral maxilla and the pterygoid region as well as the retromolar trigone without causing major sensory disturbances to the lower lip. A mental nerve anastomosis after tumor resection was performed in one patient and resulted in approximately 90% sensory recovery in the lower lip. The lower cheek flap approach provides adequate exposure of the posterolateral maxilla, including the pterygoid, retromolar trigone, and mandibular ramus areas. If the mental nerve can be anastomosed during flap approximation, postoperative sensory disturbances to the lower lip can be minimized.

Alterações da região retromolar decorrentes do crescimento mandibular / Retromolar space changes associated with mandibular growth

Objetivo: as modificações regionais inerentes ao processo de crescimento mandibular, como a reabsorção da borda anterior do ramo, determinam o aumento do espaço na região retromolar e mostram a necessidade ou não de exodontia dos terceiros molares. O objetivo deste trabalho foi avaliar, quantitativamente, o crescimento anteroposterior da região retromolar mandibular e verificar a ocorrência de dimorfismo sexual dessa variável. Material e métodos: foram utilizadas telerradiografias obtidas em norma lateral de 45 jovens, de ambos os sexos, leucodermas, entre nove e 11 anos de idade, mesofaciais, com perfis faciais harmônicos e oclusão normal. Foi aferido o espaço retromolar ao longo do plano oclusal funcional, entre a borda anterior do ramo da mandíbula e a face distal do primeiro molar inferior. Os dados obtidos submeteram-se, primeiramente, ao teste t de Student, para verificar o erro sistemático, e ao teste de correlação para o erro casual, ambos intraexaminador, indicando ausência de erro do método. Empregou-se o teste de Tukey, para comparar as medidas obtidas nas diferentes idades, e a análise de variância, para verificar a ocorrência de dimorfismo sexual. Resultados e conclusão: verificou-se um crescimento da região retromolar de 3,29 mm, entre os nove e os 11 anos. Nas idades de dez aos 11 anos ocorreu um aumento de 2,55 mm, sendo estatisticamente maior do que o constatado dos nove aos dez anos, de 0,74 mm. A análise de variância indicou ausência de dimorfismo sexual.

Objective: regional mandibular growth changes as the resorption of the anterior ramus border that increases the retromolar space determining if lower third molars need to be removed or not. The aim of this study was to evaluate, quantitatively, the mandibular alveolar sagital growth and also if sexual dimorphism was present. Material and methods: lateral cephalograms of 45 Brazilian Caucasian children of both genders, aging from 9 to 11 years, with balanced faces and good occlusion were used. The retromolar mandibular space was measured at the functional occlusal plane, from the anterior border of the ramus to the distal aspect of the lower first molar. The data was firstly examined about systematic and random intra-examiner errors through Student's "t" test and correlation test, respectively. In order to compare the data among different ages and occurrence of sexual dimorphism Anova and Tukey's test were performed. Results and conclusions: it was found an increase of 3.29 mm in the mandibular retromolar space from 9 to 11 years of age. Between 10 and 11 years there was an increase of 2.55 mm, statistically greater than those verified from 9 to 10 years of age, which was 0.74 mm. Anova demonstrated no sexual dimorphism.

Pathology of advanced buccal mucosa cancer involving masticator space (T4b).

BACKGROUND: Buccal mucosa cancer involving masticator space is classified as very advanced local disease (T4b). The local recurrence rate is very high due to poor understanding of the extent of tumor spread in masticator space and technically difficult surgical clearance. The objective of this study is to understand the extent of tumor spread in masticator space to form basis for appropriate surgical resection. MATERIALS AND METHODS: All consecutive patients with T4b‑buccal cancer underwent compartment resection, with complete anatomical removal of involved soft‑tissue structures. Specimens were systematically studied to understand the extent of invasion of various structures. The findings of clinical history, imaging and pathologic evaluation were compared and the results were evaluated. RESULTS: A total of 45 patients with advanced buccal cancer (T4b) were included in this study. The skin, mandible and lymph nodes were involved in 30, 24 and 17 cases respectively. The pterygoid muscles were involved in 34 cases (medial‑pterygoid in 12 and both pterygoids in 22 cases) and masseter‑muscle in 32 cases. Average distance for soft‑tissue margins after compartment surgery was 2 cm and the margins were positive in 3 cases. The group with involvement of medial pterygoid muscle had safest margin with compartment surgery while it was also possible to achieve negative margins for group involving lateral pterygoid muscle and plates. The involvement of pterygomaxillary fissure was area of concern and margin was positive in 2 cases with one patient developing local recurrence with intracranial extension. At 21 months median follow‑up (13‑35 months), 38 patients were alive without disease while two developed local recurrence at the skull base.CONCLUSIONS: T4b buccal cancers have significant soft‑tissue involvement in the masticator space. En bloc removal of all soft‑tissues in masticator space is advocated to remove tumor contained within space. The compartment surgery provides an opportunity to achieve negative margins for cancers actually contained within masticator space.It is inappropriate to club all patients with masticator space involvement in one group.

A study on the incidence of retromolar foramen in South Indian adult dried human mandibles and its clinical relevance.

Background: The retromolar foramen is one of the most important non-metrical anatomical variants in the mandible. The present study describes the incidence of retromolar foramen in South Indian adult dried mandibles and its clinical relevance. Methods: One hundred South Indian adult dried mandibles of unknown sex were studied at the Department of Anatomy, MVJ Medical College, Bangalore for the presence of retromolar foramen. Its location, size, shape, distance of the foramen if present from the posterior border of socket for 3rd molar tooth, anterior border of ramus of the mandible were measured. Results: Retromolar foramen was present in 16 (16%) of the mandibles. Out of the 16 mandibles, it was present bilaterally in 3 (3%) mandibles and unilaterally in 13 (13%) mandibles (In 3 (3%) on the right side and in 10 (10%) on the left side). The mean diameter of the foramen was 1.33mm (range - 1.10-1.92 mm). It was oval in shape in 9 (9%) and rounded in shape in 7 (7%) mandibles. The mean distance of retromolar foramen from the posterior border of socket for 3rd molar tooth and anterior border of ramus were 6.15 mm (2.23-12.10) and 8.02 mm (3.24-13.12) respectively. Conclusions: The knowledge about the incidence of the retromolar foramen is important for dental surgeons during various anaesthetic, implantation and surgical procedures of the mandible, especially during extraction of the lower last molar tooth.

An in vivo study to correlate the relationship of the extraoral and intraoral anatomical landmarks with the occlusal plane in dentulous subjects.

Background: The occlusal plane position is considered to be the primary link between esthetic and function. Aim: To evaluate the relationship between extraoral and intraoral soft tissue landmarks with the occlusal plane in dentulous subjects on both sides and to check for any variations. Study and Design: An in vivo study and 100 subjects with all healthy permanent teeth in normal arch and alignment were selected from Modern Dental College and Research Centre, Indore. Materials and Methods: Three custom made instruments (occlusal plane analyzer, buccinator groove relator, and level analyzer) were indigenously designed to check parallelism of the interpupillary line, ala‑tragus line, buccinator groove with the occlusal plane. Relation of retromolar pad with the occlusal plane was checked with the metallic scale. Statistical Analysis: Chi‑square test. Results: In 20.0% subjects, the occlusal plane was parallel to the interpupillary line. The posterior reference point for ala‑tragus line was middle point on right side in 56% and left side in 58% subjects. Intraorally, right side 59% and left side 62% subjects had the occlusal plane at the same level as that of buccinator groove. Right side 48% and left side 45% subjects showed occlusal plane at the middle one‑third of retromolar pad. Conclusion: The occlusal plane is not generally parallel to interpupillary line. The occlusal plane is parallel to the ala‑tragus line with middle point of tragus as posterior reference point on right and left sides. Both sides, the buccinator groove and the middle one‑third retromolar pad are coinciding with occlusal plane level.

Trígono retromolar: Temible subsito del cáncer bucal / Retromolar trigone: A dreadful subsite of oral cancer

Antecedentes: el trígono retromolar es el sector de mucosa bucal situado detrás de los arcos dentarios superior e inferior. Los resultados de su tratamiento y las tasas de supervivencia han sido esporádicamente publicados solo en series retrospectivas. Objetivo: determinar los factores que afectaron la supervivencia y el intervalo libre de enfermedad de una serie de pacientes tratados con un protocolo preestablecido. Material y métodos: estudio retrospectivo, con revisión de historias clínicas e informes de anatomía patológica. Resultados: la extensión de la cirugía en 90 pacientes operados de inicio fue resección simple en 11, asociada a resección marginal de mandíbula en 23, segmentaria de mandíbula en 40, de las cuales se reconstruyeron solo 7, y parcial de maxilar superior en 21. En el 12,2% (11/90) se agregó un vaciamiento supraomohioideo y en 87,8% (79/90) vaciamiento de los 5 niveles. El 80,5% (83/103) recibieron radioterapia posoperatoria. Solo en el 12,6% (13/103) de los pacientes se aplicó un tratamiento de preservación con quimioterapia/radioterapia secuencial. La morbilidad resultó 81,1% y la mortalidad 5,5%.El 64% de los pacientes desarrolló recurrencias, con una media del 58,3% a los 5 años. En el análisis multivariado solo los márgenes de resección tuvieron significación estadística. La supervivencia global a 5 años fue del 46,7% y libre de enfermedad del 39,1%. En el análisis mul-tivariado solo la invasión perineural, los márgenes insuficientes y las adenopatas positivas fueron estadísticamente significativos. Conclusiones: el alto número de enfermos no pasibles de un tratamiento con intención curativa, que tenen infltración ósea, invasión perineural y extensión al cuello, hacen del trígono retromolar un temible subsito del cáncer bucal.

Background: the retromolar trigone is an area of the oral mouth located behind the superior and inferior dental archs. Results of its treatment and overall survival has been sporadically published in retrospective series. Objective: to discover factors which afect survival and free of disease interval in a series of patents under a preset protocol. Methods: retrospective study, review of medical records and pathologic reports. Results: The type of surgery in 90 patents included was: simple resecton, 11; combined with marginal resecton of mandible, 23; segmentary resecton, 40 (7 of them reconstructed with fbula); and partal maxillectomy, 21. A supraomohyoid neck dissecton was addedin 11/90 (12.2%) and a complete neck dissecton of fve levels, in 79/90 (97.8%). In 80.5% of the cases (83/103) received postoperative radiotherapy. In only 12.6% of the patents (13/103), preservaton treatment with sequental chemo/radiotherapy was applied. Morbidity was 81.1 % and mortality 5.5%. Sixty four per cent of patents relapsed, with a 5 years average of 58.3%. In the multivariate analysis for recurrence, only margin resecton was statstically significant. Five years overall survival was 46.7% and free of disease 39.1%. In multivariate analysis for survival, perineural invasion, margin resecton and node metastases were statstically significant. Conclusions: The high number of patents not suitable por curative surgery usually afected by bone infltraton, perineural invasion or extension to the neck suggests that the retromolar trigone is a dreadful subsite for oral cancer.

Prevalence of Retromolar Foramen in Human Mandibles and Its Clinical Significance.

Retromolar foramen is found in the triangular area behind the lower last molar tooth and it allows the passage of neurovascular bundle that contribute to the nutrition and innervations of the pulp and periodontium of the lower teeth. In the present study one hundred and twenty mandibles were examined for the presence of retromolar foramen .Retromolar foramen was found in two mandibles bilaterally and in thirteen mandibles unilaterally (in 10 on the right side and in 3 on the left side). The distance between posterior third molar to the retromolar foramen was found to be an average of 9.8mm on the right side and 8.05mm on the left side. Distance between anterior border of ramus to retromolar foramen was found to be an average of 5.68mm on the right side and 5.77 on the left side. Retromolar foramen is surgically very significant. Knowledge of this anatomical variation can prevent complications in anaesthesia and surgical procedures in this area.

Morphometric Study of the Retromolar Triangle and Foramen in Korean Mandibles / 체질인류학회지

It has been known that the retromolar foramen is a rare anatomic variation observed in the retromolar triangle, a small triangular shaped region posterior to the mandibular third molar. Due to the neurovascular bundle passing through the retromolar foramen, this anatomical structure must be kept in mind during surgical approaches regarding the retromolar area and mandible. Therefore, the authors investigated the morphology of retromolar triangle and the existence and location of retromolar foramen in Korean. And these results were compared with that of other races. We used 308 sides of 154 Korean dry mandibles, unknown gender and age. The retromolar triangle presented predominantly a triangular shape (84.1%), and the maximum height and width were 13.7 mm and 7.1 mm, respectively. In 144 of the 308 sides, the retromolar foramen was observed (46.8%). The existence of the retromolar foramen was seen the same frequency in both sides, and based on a midsagittal line of the retromolar triangle, the retromolar foramen located in more buccal side (75%) than lingual side. The mean distance between the retromolar foramen and the distal edge of the last tooth were found to be 10.3 mm and 6.9 mm, respectively for the second and third molars. According to the present study, the northeast Asians including Korean population show the highest rate of the incidence of the retromolar foramen than other races. The findings suggest that practitioners should take the retromolar foramen into account in surgical procedures involving the retromolar area to protect the patient from the complications such as bleeding or nerve damage.

Bony and Cadaveric Study of Retromolar Region.

Retromolar area in the mandible has considerable surgical importance for dental surgeons. The anatomy of this area has not received much attention in standard texts of Anatomy. A variant foramen called retromolar foramen has been described in the literature. This foramen transmits a neurovascular bundle. Presence of this neurovascular bundle poses a risk in the surgical procedures carried out for impacted lower third molar tooth extraction. The dental surgeon should also be aware of occasional presence of this neurovascular bundle in retromolar area while infiltrating local anesthetic agents. The present study was conducted on 71 dry mandibles and 10 cadaveric specimens. In dry mandibles, the boundaries and dimensions of retromolar trigone were studied. Prevalence of retromolar foramen was recorded. The distance of retromolar foramen, if present was recorded from posterior border of socket for third molar and second molar teeth respectively. In cadavers, retromolar areas were dissected and structures related were observed.

Analgo-sedación con remifentanil para la intubación vigil con el laringoscopio retromolar de Bonfils / Analgo-sedation using Remifentanil for the awake insertion of the Bonfils retromolar Intubation Fiberscope

Introducción: se considera la intubación del paciente despierto como el método fundamental para asegurar el acceso a la vía respiratoria difícil sospechada. Para afrontar esta situación se han desarrollado nuevos dispositivos como el fibroscopio retromolar de Bonfils. Los analgésicos de acción corta y fácilmente evaluables, como el remifentanil, son elecciones excelentes para alcanzar este objetivo. Resulta importante su dosificación ya que no está desprovisto de efectos adversos. Objetivos: determinar la concentración plasmática de remifentanil que garantice un efecto analgo-sedativo óptimo para la intubación vigil con el laringoscopio retromolar de Bonfils. Métodos: Se realizó un estudio descriptivo, en la Clínica Central «Cira García¼. La muestra quedó constituida por 12 pacientes programados para cirugía espinal cervical que requirieron intubación orotraqueal debido a su incapacidad de extender el cuello. Resultados: El tiempo medio para lograr el adecuado estado de conciencia con el método anestésico empleado fue 14 ± 5,8 min. La saturación de oxígeno descendió hasta una media de 94,2 ± 5,8 %. Los valores de tensión arterial media (TAM), frecuencia cardiaca (FC) y frecuencia espiratoria (FR) fueron 100,7 ± 17 mmHg, 77,6 ± 9,8. min-1 y 13,9 ±39 min-1 respectivamente. Presentaron recuerdos durante el procedimiento 4 pacientes, que refirieron estar satisfechos con el proceder. La concentración plasmática (Cp) de remifentanil calculada, necesaria para tener condiciones de intubación apropiadas fue de 0,0027 ± 0,005 µg/mL. Conclusiones: El empleo de remifentanil en dosis adecuadamente calculadas para alcanzar el efecto analgo-sedativo, para abordar la vía respiratoria difícil con el fibroscopio retromolar de Bonfils, en pacientes despiertos, fue una estrategia apropiada.

Background: The awake tracheal intubation of patients is considered as the essential method to guarantee the access to the suspected difficult airway. In order to face this problem, new disposals as the Bonfils retromolar Intubation Fiberscope have been developed. Short action and easily evaluated analgesics such as Remifentanil constitute an excellent election to achieve this goal; nevertheless, its dosage is very important as it is not free of adverse effects. Objectives: To determine the concentration of Remifentanil in plasma that guarantees an optimal analgo-sedation for the awake tracheal intubation of patients with the Bonfils retromolar Intubation Fiberscope. Methods: A descriptive study was carried out at "Cira García" Central Clinic. The sample was composed by 12 patients that were scheduled for cervical spine surgery that required orotracheal intubation because of their inability to stretch the neck. Results: The average time to achieve an adequate state of consciousness with the applied anaesthetic method was 14 ± 5,8 min. Oxygen saturation decreased to an average of 94,2 ± 5,8 %. The values of mean arterial blood pressure (MAP), cardiac frequency (CF) and expiratory rate (ER) were 100,7 ± 17 mmHg, 77,6 ± 9,8. min-1 y 13,9 ±39 min-1 respectively. Four patients had memories during the procedure and reported to be satisfied with it. The calculated plasma concentration (PC) of Remifentanil, also necessary to achieve adequate intubation conditions, was 0,0027 ± 0,005 µg/mL. Conclusions: The use of Remifentanil in properly calculated doses to achieve the analgo-sedation effect to tackle the suspected difficult airway with the Bonfils retromolar Intubation Fiberscope for the wake tracheal intubation of patients was an adequate strategy.

Avaliação morfológica da região retromolar para enxertos ósseos através de tomografia computadorizada (TC) de feixe cônico: um estudo com 60 pacientes / Morphological evaluation of the retromolar region for bone grafting procedures using cone-beam tomography: a study with 60 patients

A perda dentária possui forte impacto na qualidade de vida, ocasionando problemas de ordem funcional e emocional. Após a perda do elemento dental, o rebordo alveolar passa por um processo de reabsorção e isso impossibilita a colocação de implantes, por esse motivo, o enxerto ósseo é a técnica de escolha para solucionar tal problema. O objetivo deste estudo foi avaliar a morfologia da região retromolar, uma área utilizada para remoção de enxertos ósseos, em imagens de tomografia computadorizada (TC) tipo cone-beam para a reconstrução volumétrica, com a finalidade de determinar a altura e a espessura da área doadora disponível nessa região, utilizando como referência as corticais do canal mandibular e estabelecer uma média de quantidade óssea dessa região em uma amostra da cidade do Recife, Brasil. Material e Métodos: nesta amostra foram incluídos pacientes de ambos os sexos, com idade acima de 28 anos e sem limite de idade, que tinham presença dos segundos molares superiores e ausência de terceiros molares inferiores. A ferramenta de mensuração linear em milímetros foi utilizada para obter as medidas. Resultados e Conclusão: os homens apresentaram maior altura do canal mandibular do que as mulheres (p < 0,001), o sexo feminino apresentou maior quantidade de osso medular em comparação com o sexo oposto (p < 0,001), a quantidade de osso compacto foi relativamente maior do que o osso medular em ambos os gêneros

Tooth loss has a strong impact on quality of life, causing functional and emotional problems. After tooth loss, the alveolar ridge undergoes resorption and this precludes implant placement; therefore, bone grafting techniques are indicated for such situations. The aim of this study is to evaluate the morphology of the retromolar region through CBCT scanning for available heights and widths using the mandibular canal as reference point in a population of Recife, Brazil. Materials and methods: 200 patients of both genders above 28 years with their second molar teeth and the lack of lower third molars were selected. A linear measurement tool was used to generated data. Results and conclusions: from the final 60 selected patients and within the limits of this study, the height of the alveolar mandibular canal was higher in male than in female (p < 0.001), the female presented more medulary bone (p < 0.001), and the compact bone quantity was higher than medulary bone for both genders.

Lower third molar region / Región del tercer molar inferior

The lower third molar region is an important region for the odontostomatological practice, since it presents a great amount of pathological processes related to the development and eruption of the third molar; thus having a considerable number of surgical interventions. Despite its importance, this region is not accounted for in anatomical terminology nor is it described in topographic anatomy; and in spite of the great number of studies that analyze the surgical anatomy of the region, it is necessary to systematize the description of its boundaries, planes, content, risk elements, anatomical repairs, etc.; therefore, the purpose of the present article is to review the modern concepts related to the surgical anatomy of the lower third molar region and to establish a description based on these concepts...

La región del tercer molar inferior es una región importante para la práctica odontoestomatológica, en ella se presenta una gran cantidad de procesos patológicos relacionados con el desarrollo y erupción del tercer molar, por lo que se practican un gran número de intervenciones quirúrgicas. No obstante su importancia, esta región no se encuentra considerada en la terminología anatómica ni descrita en la anatomía topográfica y a pesar de la gran cantidad de estudios que analizan la anatomía quirúrgica de la región, es necesario sistematizar la descripción de sus límites, planos, contenidos, elementos de riesgo, puntos de reparo, etc., es por ello que el propósito de este artículo es revisar los conceptos modernos relacionados con la anatomía quirúrgica de la región del tercer molar inferior y proponer una descripción basada en estos conceptos...