Osteometric and radiological study of the mandibular notch / Estudio osteométrico y radiológico de la incisura mandibular

The mandibular notch is located on the superior margin, between two prominent processes of the mandibular ramus, the coronoid and condylar processes. The mandibular notch permits the entry of the masseteric artery, vein and nerve to the deep surface the masseteric muscle. Literary reports documented variations in both, the shape and size of the mandibular notch. Therefore, this study aimed to document the morphology and morphometry of the mandibular notch in the South African Black and Indian population groups and to determine their relationship to sex, age and race (if any). The morphometric and morphological parameters of the mandibular notch were measured and assessed in 149 digital panoramic radiographs and 51 dry mandible specimens (n=400) belonging to the South African Black African and Indian population groups. A combination of classification schemes by Mohammad et al. (2012) and Shakya et al. (2013) were adopted to assess the morphology of the mandibular notch. The morphometric parameter was measured using the Dicom x-ray viewer and a digital vernier caliper. Each of the morphometric and morphological parameters were statistically analyzed using SPSS, to determine if a relationship existed between the afore-mentioned parameters and sex, age and race. This study recorded the round shaped mandibular notch to be the most prevalent type in both sexes with a combined incidence of 44.2 %. The length of the mandibular notch was reported to be greater in males than females and concurred with previous studies. However, the selected South African group displayed a smaller mandibular notch than the Japanese and Chinese population groups. Furthermore, this study documented population differences among the South African population group, as the Black African population group showed a wider mandibular notch than the Indian population group. This suggests that population-specific differences may exist for both the morphological and morphometric parameters of the mandibular notch. However, only a statistically significant relationship between the length of the mandibular notch with age and race was documented. The mandibular notch may be of clinical significance to maxillofacial surgeons for surgical and reconstructive procedures, in addition it may also aid forensic anthropologists in the identification of unknown remains.

La incisura mandibular se encuentra en el margen superior, entre dos procesos importantes de la rama mandibular, el proceso coronoides y el proceso condilar. La incisura mandibular permite la entrada de la arteria, la vena y el nervio masetérico en la superficie profunda del músculo masetero. En la literatura se han documentado variaciones tanto en la forma como en el tamaño de la incisura mandibular. Este estudio tuvo como objetivo documentar la morfología y la morfometría de la incisura mandibular en los grupos de población de negros e indios sudafricanos y determinar su relación con el sexo, la edad y la raza. Los parámetros morfométricos y morfológicos de la incisura mandibular se midieron y evaluaron en 149 radiografías panorámicas digitales y 51 especímenes de mandíbula seca (n = 400) pertenecientes a los grupos de población sudafricana negra e india. Una combinación de esquemas de clasificación de Mohammad et al. (2012) y Shakya et al. (2013) fueron adoptados para evaluar la morfología de la incisura mandibular. El parámetro morfométrico se midió utilizando el visor de rayos X Dicom y un calibrador Vernier digital. Cada uno de los parámetros morfométricos y morfológicos se analizaron estadísticamente utilizando el software SPSS, para determinar si existía una relación entre los parámetros mencionados anteriormente y el sexo, la edad y la raza. Este estudio registró la incisura mandibular de forma redonda como el tipo más prevalente en ambos sexos, con una incidencia de un 44,2 %. Se informó que la longitud de la incisura mandibular es mayor en hombres que en mujeres y coincidió con estudios anteriores. Sin embargo, el grupo sudafricano seleccionado mostró una incisura mandibular más pequeña que los grupos de población japoneses y chinos. Además, se documentó las diferencias de población entre el grupo de Sudáfrica, ya que el grupo de población negra de África mostró una incisura mandibular más amplia que el grupo de la población India. Esto sugiere que pueden existir diferencias específicas de la población para los parámetros morfológicos y morfométricos de la incisura mandibular. Sin embargo, solo se documentó una relación estadísticamente significativa entre la longitud de la incisura mandibular con la edad y la raza. La incisura mandibular puede ser de importancia clínica para los cirujanos maxilofaciales en procedimientos quirúrgicos y reconstructivos; además, también puede ayudar a los antropólogos forenses en la identificación de restos desconocidos.

Cross Sectional Analysis Of Occurrence Of Accessory Mandibular Foramina And Their Positional Variations In Dry Mandibles

Background: During lower jaw surgeries, inferior alveolar nerve block is given at mandibular foramen level.However, additional foramina are found on medial surface of ramus of mandible, through which branches ofinferior alveolar nerve and vessels pass. Location of accessory foramina varies widely which could lead toiatrogenic injuries to neurovascular structures in this region.Aim and objective: Precise information of variations in number of mandibular foramen and position of theseaccessory foramina relative to mandibular foramen help dental surgeons to avoid injuries to inferior alveolarnerve and vessels. Hence, this study aimed at analyzing position of accessory foramina osteologically in Gujarat’spopulation.Materials and Methods: Three hundred dry mandibles of unknown sexes, and bearing all teeth or intact alveolarmargin were included in the study. Numerical variations in the form of accessory foramina were found in 42% ofthe mandibles; 17% on the right side; 17.66% on the left side; and in 7.33% mandibles accessory foramina werepresent on both sides. The laterality distribution of accessory mandibular foramina was found to be insignificantstatistically. More number of accessory foramina was located antero-superior to mandibular foramen. Retromolarforamina were found in 15% mandibles; however, laterality distribution of retromolar foramina was statisticallyinsignificant.Conclusion: Latrogenic injuries of inferior alveolar neurovascular structures could better be avoided with preciseidea of position of accessory foramina, which may ease the work of dental surgeon

An osteometric evaluation of the mandibular condyle in a black KwaZulu-natal population / Una evaluación osteometrica del cóndilo mandibular en una población negra KwaZulu-natal

The mandibular condyle is the rounded protuberance that articulates with the mandibular fossa to form the temporomandibular joint (TMJ). The shape of the mandibular condyle may be classified according to five basic shapes viz. flattened, convex, angled, rounded and concave. Previous research indicated that variation in the shape and size of the mandibular condyle, exists and that population-specific differences may also occur. This study aimed to document the shapes and size of the mandibular condyle and determine their relationship with regard to sex, age and race (if any). The morphometric and morphological parameters of the mandibular condyle were measured and assessed in 54 dry mandible specimens (n= 108). The Wedel et al. (1978) classification scheme was adopted in order to document the morphology of the mandibular condyle, utilizing three different aspects. Each of the morphometric and morphological parameters was statistically analyzed using SPSS, to determine if a relationship existed between the afore-mentioned parameters and sex, age and race in each specimen. In the anterior view, the most prevalent shape of the mandibular condyle was the plane/slightly convex shape (62.0 %), while the round/oval shape was most prevalent in the superior view (56.5 %), with the plane/slightly convex shape being most prevalent in the lateral view (69.4 %). All morphometric parameters of the mandibular condyle were greater in male than females, which correlated with previous studies. When both sides were compared, statistically significant different relationships were recorded only between: i) sex and the right mandibular condyle in the superior and lateral views; ii) between age and the right mandibular condyle in the superior view. In addition, all morphometric and morphological parameters recorded in this study displayed a statistically significant relationship with race. Knowledge of the anatomy of the mandibular condyle may aid in clinical and surgical procedures, viz. TMJ disorders and mandibular condyle fractures, as well as in the design of population-specific condylar prostheses.

El cóndilo del proceso condilar es la protuberancia redondeada que se articula con la fosa mandibular para formar la articulación temporomandibular (ATM). La forma del cóndilo mandibular (CM) se puede clasificar de acuerdo a cinco formas básicas: aplanada, convexa, en ángulo, redondeada y cóncava. Investigaciones anteriores indican que existe variación en la forma y tamaño del CM, y también podrían observarce diferencias específicas en la población. El objetivo fue documentar las formas y tamaños del CM, y determinar su relación con respecto al sexo, edad y raza (si los hay). Los parámetros morfométricos y morfológicos del CM se midieron y evaluaron en 54 especímenes de mandíbula secos (n= 108). Se adoptó el sistema de clasificación de Wedel et al. (1978) con el fin de documentar la morfología del CM, utilizando tres aspectos diferentes. Cada uno de los parámetros morfométricos y morfológicos se analizó estadísticamente con el programa SPSS, para determinar si existía una relación entre los parámetros antes mencionados y el sexo, edad y raza de cada espécimen. La forma más frecuente del CM fue la plana/ligeramente convexa (62,0 %) desde una vista anterior, mientras que la redondeada/óvalada fue más prevalente en la vista superior, (56,5%), con la forma plana/ligeramenta convexa más prevalente en la vista lateral (69,4 %). Todos los parámetros morfométricos del CM fueron mayores en los hombres, y se correlacionaban con estudios anteriores. Cuando se compararon ambas partes, se registraron relaciones estadísticamente significativas diferentes sólo entre: i) el sexo y el CM derecho en las vistas superior y lateral; ii) entre la edad y el CM derecho en la vista superior. Además, todos los parámetros morfométricos y morfológicos registrados en este estudio muestran una relación significativa con la raza. El conocimiento de la anatomía del CM puede ayudar en los procedimientos clínicos y quirúrgicos, en los trastornos de la ATM y las fracturas de CM, así como en el diseño de prótesis condilar específica para la población.

Localization of mandibular foramen relative to landmarks in East Indian mandibles.

Context: The position of mandibular foramen (MF) is an important anatomical landmark for effective anesthesia in dentistry for many procedures, including dental extraction from the lower jaw and putting mandibular implants. Several causes have been examined in this context, and the uncertainty in the location of the MF has been examined to be a major factor for the high failure rate of anesthesia and complications of the orthodontic procedure. Aims: The purpose of this study was to examine and analyze the position of the MF relative to six bony landmarks on the ramus in the population of Jharkhand. Subjects and Methods: The different parameters were measured in 30 dry adult’s mandibles that were obtained from the Department of Anatomy. The data were tabulated and statistically analyzed. Statistical Analysis Used: Paired t‑test. Results: The mean distance between the MF and the respective landmarks was noted as 16.00 ± 3.50 mm for the anterior border, 10.21 ± 2.34 mm for the posterior border, 20.48 ± 3.89 mm for the superior border, 24.15 ± 4.97 mm for the inferior border, 33.46 ± 6.08 mm for the condyle, and 12.31 ± 4.88 mm for the internal oblique ridge for the right side. On the left side, these distances were 16.27 ± 3.9 for the anterior border, 10.28 ± 5.24 for the posterior border, 20.15 ± 3.8 for superior border, 24.86 ± 4.04 for inferior border 32.48 ± 4.73 for condyle, and 10.93 ± 4.06 for the inferior oblique ridge. Statistically, there was no significant difference in the distance to either side from selected 5 landmarks, the only exception being the condyle. Conclusions: Condyle and internal oblique ridge have been shown to be two new landmarks that may be used to find MF. Bilateral symmetry has been shown for all landmarks except for condyle.

Does matching relation exist between the length and the tilting angle of terminal implants in the all-on-four protocol? stress distributions by 3D finite element analysis

PURPOSE: To explore whether there is matching relation between the length and the tilting angle of terminal implants in the All-on-Four protocol by studying the effects of different implant configurations on stress distributions of implant, bone, and framework. MATERIALS AND METHODS: Four implants were employed to support a full-arch fixed prosthesis and five three-dimensional finite element models were established with CT images, based on the length (S and L) and distal tilt angle (0degrees, 30degrees and 45degrees) of terminal implants for an edentulous mandible, which named: Tilt0-S, Tilt30-S, Tilt30-L, Tilt45-S and Tilt45-L. An oblique 240 N was loaded at second molar. The von Mises Stresses were analyzed. The implants were consecutively named #1 to #4 from the loading point. RESULTS: 1) Tilt0-S had the greatest stress on the implants, with the other groups exhibiting variable reductions; the four implants of Tilt45-L demonstrated the greatest reduction in stress. 2) Tilt0-S had the greatest stress at bone around #1 implant neck, and Tilt45-L exhibited the least stress, which was a 36.3% reduction compared to Tilt0-S. 3) The greatest stress in the framework was found on the cantilevers distal to #1 implant. Tilt45-S exhibited the least stress. CONCLUSION: Matching different length and tilting angle of the terminal implants led to variable stress reductions on implants, bone and the superstructure. By optimizing implant configuration, the reduction of stress on implants and surrounding bone could be maximized. Under the present condition, Tilt45-L was the preferred configuration. Further clinical testings are required.

Incidence of the mandibular accessory foramina in Brazilian population

In adults, the mandibular accessory foramina are variables and are located on the medial surface of the mandible in positions above or below of the mandibular foramen. The aim of this study was to evaluate the incidence of the mandibular accessory foramina in Brazilians human mandibles and discuss the clinical aspects related to the presence of these foramina. Were evaluated 222 mandibles, adults, irrespective of gender. Was observed that 27.93% and 43.24% of the mandibles presented at least one mandibular accessory foramina located on the medial surface in position below and above, respectively, of the mandibular foramen. Unilaterally, the mandibular accessory foramina were observed below and above of the mandibular foramen in 22.07% and 25.22%, of the mandibles, respectively, and 5.85% and 18.02% bilaterally, respectively. This study demonstrated that the incidence of mandibular accessory foramen in the Brazilian population is significant and should be considered in the planning and execution of procedures in several areas of dental clinical practice in order to avoid complications.

Morphological analysis of the lingula in dry mandiblesof individuals in Southern Brazil

The lingula of the mandible is a small-tongue-shaped bone projection overlaying the mandibular foramen, andit is clinically significant in oral and maxillofacial surgical procedures. This study aims to analyze the shapesof the lingula and its relationship with the surface of the mandibular ramus, and to record data about thepopulation in Southern Brazil. The maxillofacial study of the lingula in 80 dry mandibles in adult individualswas conducted. The lingula of the two rami of each mandible were assessed and classified in the followingshapes: triangular, truncated, nodular and assimilated. The triangular shape was analyzed according to itsdirection in relation to the condyle or the posterior region of the mandible posterior ramus, and also accordingto its relationship with the inner surface of the mandibular ramus: assimilated, free or partially free. Theoccurrence of accessory mandibular foramens in each mandibular ramus was also recorded. The triangularshape of the lingula was found in 66 sides (41.3%), seeing that in 21 mandibles (42 sides) it was noticed bothon the right side and the left side, whereas 13 occurred on the right side and 11 on the left side, unilaterally.The truncated lingula was present on 58 sides (36.3%), and the nodular lingula was noticed on 17 sides(10.5%); as to the assimilated lingula it was found on 19 sides (11.9%). Accessory foramens were foundin 11.3 and 3.8% of the right and left mandibular rami, respectively. Considering that the lingula showsmorphological variants in different populations, these results include significant data of the population in theSouth of Brazil regarding the morphometric study of the mandible, also playing a role to avoid failure of theanesthetic surgical block of the inferior alveolar nerve.

Location of the mental foramen in dry mandibles of adultindividuals in Southern Brazil

The mental foramen (MF) guides the mental nerve which is responsible for the sensible innervation of themandibular area. It is important to know the anatomical variations of the MF for locational blockage of theincisor nerve in periapical surgeries involving molars and premolars, and in other buccomaxillofacial surgicalprocedures as well. This study aims to analyze variations in the MF site in dry mandibles of adult subjects inSouthern Brazil. Eighty mandibles were analyzed, and the measurements of the distance from the sagittalmidline to the center of the MF (MLF); the distance from the lower rim of the mandible to the center ofthe MF (LRF); the location of the MF relative to its alignment with the mandible teeth, and the incidenceof double mental foramens (DMF) were checked. The analyzed parameters were related to each mandible’slaterality. Statistical analysis was carried out through Student’s t test. Results indicate that the prevalentposition of the MF in the right and left sides was posterior to the first premolar. There was no significantdifference between the right and left sides regarding MLF, and LRF showed a significant difference betweensides, greater on the right side. There was a prevalence of the DMF on the right side of the mandibles. Theseresults are important for the preparation and conduction of surgical procedures in order to prevent injury tothe involved neurovascular structures.

Sex determination in mandibles in the first year of life by a quantitative approach / Determinación del sexo en mandíbulas en el primer año de vida mediante una aproximación cuantitativa

Numerous studies have shown that skeletal characteristics vary among different populations. Several authors suggest that it is possible to determine sex through the anatomical evaluation of children mandible, however there are few morphometrical studies conducted with such specimens. The purpose of this study was to analyze several mandibular dimensions and identify the ones that could be useful to perform sex differentiation in a sample of Brazilian young children. For this study we used 32 children dry mandibles of known sex, age ranging from 0 to 1 year old. The mandibles pertain to the collection of the Skull Museum of the Universidade Federal de Sao Paulo (UNIFESP). The parameters included bicondilar width, bigonial width, minimum width and height of the mandibular ramus, gonion-gnation length, height of the mandibular symphysis and transverse and anteroposterior condylar dimensions. The SPSS program was used to carry on the discriminant function analysis and the T test (p <0.05). There were no statistically significant differences that could allow identification of a specific parameter for sex determination. However, most of the dimensions were higher in male than in female, except for the minimum width of the mandibular ramus (0.2-0.16 mm) and transverse diameter of the right condyle (0.16mm). The values obtained for the anteroposterior diameter of the mandibular head were the most different between genders, although no statistically significance was found. Discriminant function analysis indicated that, despite differences, none of the evaluated parameters allow for sex classification with enough reliability. In conclusion, there is little sexual dimorphism in children's mandibles during the first year of life and anatomical analysis of this structure is not recommended as reliable quantitative approach for sex differentiation with forensic purposes.

Numerosos estudios han demostrado que las características esqueletales varían en las distintas poblaciones. Diversos autores indican que es posible la determinación del sexo en base a mandíbulas infantiles; sin embargo, existen escasos estudios morfométricos realizados en mandíbulas de niños brasileros. El propósito de este estudio fue analizar distintas dimensiones de mandíbulas y determinar aquellas de utilidad en el diagnóstico forense del sexo, en población infantil brasilera. Se utilizaron 32 mandíbulas de niños brasileros de entre 0 y 1 año de edad, de sexo conocido, pertenecientes a la colección de cráneos de la Universidade Federal de Sao Paulo (UNIFESP). Las mediciones mandibulares incluyeron ancho bicondilar, ancho bigonial, ancho mínimo y altura de la rama mandibular, longitud gonion- gnation, altura de la sínfisis mandibular y las dimensiones transversa y anteroposterior del cóndilo. Los datos obtenidos fueron sometidos al t test (p<0,05) y análisis de la función discriminante con SPSS. La mayoría de las dimensiones fueron superiores en hombres que en mujeres, con excepción del ancho mínimo de la rama mandibular (0,2-0,16 mm) y del diámetro transverso del cóndilo derecho (0,16 mm). El diámetro anteroposterior de la cabeza mandibular resultó la más dimórfica de las medidas analizadas, aunque ninguna diferencia resultó estadísticamente significativa. El análisis de la función discriminante indicó que a pesar de las diferencias, éstas no permiten clasificar de acuerdo al sexo, en base a las variables cuantitativas analizadas. En conclusión, la mandíbula de niño en el primer año de vida presenta escaso dimorfismo sexual y no se recomienda el abordaje cuantitativo para la determinación del sexo con fines forenses.

The mental foramen position in dentate and edentulous Brazilian's mandible

The mental foramen has been reported to vary in position in different ethnic groups. Repeated failures during injections and operative procedures involving the mental foramen suggest the presence of local differences in a given population. The aim of the present study was to determine the position of mental foramen (MF) in a sample of one hundred seventy Brazilian adult dry mandible, being 79 edentulous and 91 dentate. The assessment was made, having as it referential, the base of the mandible (BM) and the mandibular symphisis (MS), whereby the comparisons were carried out considering genders, the mandible side (left or right), and dentition (dentate or edentulous). The statistical analysis was performed using multifatorial ANO VA (alpha=5 percent). It was found the male mandibles presented higher values of MF-MS than the female ones and the dentate presented higher values when compared to edentulous ones (p<0.0001). No difference was observed between left and right sides (p=0.2990), as well, as concerning to gender (p=0.152). The most frequent position of MF was in the long axes of the second premolar for male (p<0.0001) and female (p=0.0004). No statistical difference (p>0.05) was found between right and left sides comparing male to female. It was concluded the position of the mental foramen is mainly altered in edentulous subjects as it is consider a symmetric structure in Brazilian population and its most common position is in the long axes of the second premolar.

El foramen mental ha sido reportado variablemente en diferentes posiciones, según los grupos étnicos. Repetidos errores durante el procedimiento anestésico, que involucran al foramen mental, sugieren la presencia de diferencias locales en una determinada población. El objetivo del presente estudio fue determinar la posición del foramen mental (MF) en una muestra de 170 mandíbulas secas de la población brasileña, siendo 79 desdentadas y 91 dentadas. La evaluación fue hecha teniendo como referencia la base de la mandíbula (BM) y la sínfisis mandibular (MS). La comparación fue dada y llevada por géneros, según el lado de la mandíbula (izquierdo o derecho) y la dentición (dentada o desdentada). El análisis estadístico fue realizado usando el test multifactorial ANOVA (alpha 5 por ciento). Mandíbulas masculinas presentaron valores mayores que el grupo femenino y las mandíbulas dentadas presentaron valores superiores, cuando fueron comparadas con las mandíbulas desdentadas (p<0.0001). Ninguna diferencia fue observada entre los lados derecho e izquierdo (p=0.2990), como tampoco para los géneros masculino y femenino (p=0.152). La posición más frecuente de MF para las mandíbulas masculinas fue a lo largo del eje del segundo premolar (p<0.0001), así como para las mandíbulas femeninas (p=0.0004). No fueron encontradas diferencias estadísticamente significativas (p>0.05) entre los lados derecho e izquierdo, comparando mandíbulas masculinas y femeninas. Se concluye que la posición del foramen mental es principalmente alterada en sujetos desdentados, es considerada una estructura simétrica en la población brasilera y más comúnmente localizado a lo largo del eje del segundo premolar.

Anatomical Study on the Location of the Mental Foramen in Adult Korean Mandibles / 체질인류학회지

We examined the anatomical position of the mental foramina in mandibles foramen normal adult Koreans. 1. The percentages obtained from the study of the relationships between the mental foramen and the lower teeth showed that the most common location was type lv in which the mental foramen lay at the apex of the second promolar. The foramen between thr apices of ice two premolars (type lll) and the foramen between the second premolar and the first molar (type v) occured often and less often rspectively and find no foramen mesial to the first premolar or at the apex of the first premolar and posterior of the first molar (type l, ll, vl). 2. The study of relationship of the mental foramen to the bo of the mandible revealed that mental foramen was situated closer to the lowed border of the mandibular body. The distance ratio between the mental foramen and the alveolar crest to that between the mental foramen and the lower border was approximately 1.2 : 1. The height of the mandibular body was 31.09±2.80mm on the left side and 30.97±2.48mm on the right. 3. The distance from the mandibular symphysis to the anterior border of the mental foramen measured 29.52±2.01mm on the left, 30.82±2.04mm on the right side, and from the mandibular symphysis to the posterior border of the mandibular ramus was 104.20±4.74mm on the left, 105.44±4.49mm on the right side. It indicates that the mental foramen lies approximately at one-fourth of the distance from the mandibular symphysis to 2017-04-19 the posterior border of the ramus. 4. The distance from the superior border of the mental foramen to the bottom of the lower second premolar socket was found to be positive. It was 5.46±3.09mm on the left, 5.73±3.03mm on the right side. This indicates that the bottom of the lower second premolar socket is slightly higher than the superior border of the mental foramen.