Paulo Henrique Ferreira Caria

Electromyographic Activity of Masseter and Temporal Muscles with Different Facial Types

OBJECTIVES To compare the electromyographic (EMG) activity of the masseter and anterior portion of temporal muscles in different vertical facial types. MATERIALS AND METHODS Clinical examination, cephalometric analysis, and electromyographic examination were performed in 44 volunteers ranging from 18 to 35 years old. The volunteers were classified on the basis of their vertical facial characteristics into three groups-brachyfacial, mesofacial, and dolicofacial-by the grouping analysis. The EMG records were obtained with three repetitions during mandibular rest, maximum voluntary contraction in intercuspidation, and simultaneous bilateral isotonic contraction. The Kolmogorov-Smirnov and Levene tests were applied to verify the normality and homogeneity of variance. Analysis of variance and the Kruskal-Wallis test identified statistical differences among groups that did not present normality and homogeneity of distribution, respectively. Significance for all statistical tests was set at P < .05. RESULTS At rest, only the right temporal and masseter muscles presented statistically significant differences among the groups. The differences were observed between groups 1 and 2 (P = .02) and 1 and 3 (P = .038) for the right temporal muscle, and between groups 1 and 2 (P = .029) for the right masseter muscle. Generally, group 1 presented the lowest EMG values for the four muscles evaluated during rest. For isotonic evaluation, none of the groups of muscles presented statistically significant differences. CONCLUSION Different vertical facial types do not determine distinct patterns of EMG activity for the masseter and anterior portion of temporal muscles during rest and bilateral mastication.

Incidence of Retromolar Foramen in Human Mandibles: Ethnic and Clinical Aspects

SUMMARY: The retromolar foramen allows the passage of the neurovascular bundles that contribute to nutrition and innervation of the pulp and periodontium of the lower teeth. Knowledge of this anatomical variation may prevent complications in the anesthesia and surgical procedures in this area and serve as an anatomical landmark for ethnic identification. The aim of this study was to evaluate the impact of the retromolar foramen in human mandibles of adult Brazilians and discuss the clinical and ethnic related to the presence of this foramen. Were evaluated 222 human mandibles, dry, adults, Brazilians, independent of gender. The evaluation was performed by two examiners who standardized search from a previous anatomical study. The mandibles were analyzed: the presence of the retromolar foramen (bilateral or unilateral), the presence of the foramen on right and left sides, and the number of foramens present on each side. It was found that 59 had at least one mandible retromolar foramens resulting in an incidence of 26.58%. The retromolar foramen was present unilaterally in 41 mandibles and 18 bilaterally, with incidences of 18.47% and 12.16% respectively. On the right side, the retromolar foramen was present in incidences of 16.22% and 18.92% respectively. The analysis of the right side of the mandibles revealed that 47.46%, 21.21% and 3.03% had one, two and three foramens, respectively. The left side showed 55.93%, 16.22% and 8.11% of the 222 mandibles with one, two and three retromolar foramens, respectively. The incidence of retromolar foramen in the Brazilian population is significant and should be considered in the planning and execution of procedures in several areas of clinical practice dentistry in order to avoid complications. Moreover, it was found that the incidence of retromolar foramen contributes to differentiation of ethnic groups in the area of forensic anthropology. ˚

Morphological changes in the position of the mandibular foramen in dentate and edentate Brazilian subjects.

This study assessed the mandibular foramen (MF) position variability in dentate and edentate Brazilian mandibles. Eighty dentate and 79 edentate mandibles of unknown sex were measured bilaterally using a digital caliper (0.1‐mm precision). Horizontal linear measurements (HM) were done from the MF to the anterior border of the mandibular ramus (MF‐A) and from the MF to the posterior border of the mandibular ramus (MF‐B). Vertical linear measurements (VM) were done from the MF to the most inferior point of the mandibular notch (MF‐C) and from the MF to the inferior border of the mandibular ramus (MF‐D). Data were analyzed by two‐way ANOVA (alpha = 5%). The HM means and standard deviations (±SD) for MF‐A were, edentate right (ER): 17.5 (±3.2) mm, edentate left (EL): 17.4 (±3.4) mm, dentate right (DR): 19.2 (±3.6) mm, and dentate left (DL): 18.8 (±3.8) mm. The means (±SD) for the MF‐B measurements were, respectively, ER: 12.8 (±2.4) mm, EL: 12.9 (±2.3) mm, DR: 14.2 (±2.4) mm, and DL: 13.9 (±2.6) mm. The VM values for the MF‐C measurements were, ER: 23.4 (±3.8) mm, EL: 22.9 (±3.7) mm, DR: 23.6 (±3.1) mm, and DL: 23.1 (±3) mm, and for the MF‐D measurements, ER: 26.4 (±4.2) mm, EL: 26.4 (±4) mm, DR 28.3 (±3.9) mm, and DL 28 (±3.8) mm. Side had no influence (p>0.05) on any edentate or dentate mandible measurement. Dentate mandible measurements showed statistically significant differences compared to the edentate mandibles, except for MF‐C. The mandibular foramen position changes with loss of teeth and this variability may be responsible for occasional failure of inferior alveolar nerve block. Clin. Anat. 23:394–398, 2010.

Canalis sinuosus: a rare anatomical variation

The infraorbital canal issues a small branch on its lateral face close to its midpoint to allow passage of the anterior superior alveolar nerve. This small canal, sometimes called the canalis sinuosus, runs forward and downward to the inferior wall of the orbit, lateral to the infraorbital canal and medially bent to the anterior wall of the maxillary sinus, passing below the infraorbital foramen. Anatomical variations in the maxilla are rarely described in the literature and, in most cases, are related to the nasopalatine canal. This article describes a rare anatomical variation of the presence of a bilateral accessory canal extending from the nasal cavity lateral wall to an accessory foramen located on the hard palate, adjacent to the maxillary lateral incisor observed in cone beam computed tomography (CBCT) images. This case is an anatomical variation of the anterior superior alveolar nerve (canalis sinuosus). Identification of individual anatomical variations, especially on CBCT, may help the surgeon to avoid injuries to nerves during implant placement.

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

El foramen mental ha sido reportado variablemente en diferentes posiciones, segun los grupos etnicos. Repetidos errores durante el procedimiento anestesico, que involucran al foramen mental, sugieren la presencia de diferencias locales en una determinada poblacion. El objetivo del presente estudio fue determinar la posicion del foramen mental (MF) en una muestra de 170 mandibulas secas de la poblacion brasilena, siendo 79 desdentadas y 91 dentadas. La evaluacion fue hecha teniendo como referencia la base de la mandibula (BM) y la sinfisis mandibular (MS). La comparacion fue dada y llevada por generos, segun el lado de la mandibula (izquierdo o derecho) y la denticion (dentada o desdentada). El analisis estadistico fue realizado usando el test multifactorial ANOVA (alpha 5%). Mandibulas masculinas presentaron valores mayores que el grupo femenino y las mandibulas dentadas presentaron valores superiores, cuando fueron comparadas con las mandibulas desdentadas (p 0.05) entre los lados derecho e izquierdo, comparando mandibulas masculinas y femeninas. Se concluye que la posicion del foramen mental es principalmente alterada en sujetos desdentados, es considerada una estructura simetrica en la poblacion brasilera y mas comunmente localizado a lo largo del eje del segundo premolar.

Caroticoclinoid foramen in human skulls: incidence, morphometry and its clinical implications

The caroticoclinoid foramen is an inconstant structure, formed by the union of the anterior and middle clinoid processes. The aim of this study was to perform an incidence and morphometry of the caroticoclinoid foramen in Brazilian human skulls and discuss its clinical implications. Eighty dry human skulls with sex distinction were used, and 3 groups of incidence were determined: General, sex, and sides. The morphometry was performed using a manual caliper and the major diameter of the foramina was measured; the values were also divided in general, according to sex and sides. The incidence of skulls with at least one foramen was 8.5%. According to the sides, 8.5% of the skulls showed foramen on the right side and 2.5% on the left. We found 2.5% of the skulls with bilateral foramen and 6.25% with unilateral foramen. In relation to sex, the foramens were found in 5% of male skulls and 12.5% of female skulls. The major diameter of this structure presented on mean, values of 5.23 mm on general, 5.18 mm on the right side and 5.35 mm on the left, 5.30 mm in male skulls and 5.18 mm in female skulls. The anatomical characteristics of this foramen should be considered in view of its clinical implications associated with neurosurgery as clinoid process removal, and symptoms as headache due to internal carotid artery alterations in this region. In conclusion knowledge of this structure supports the diagnosis and treatment of clinical complications related to this variation.

Morphological Description of Mandibular Canal in Panoramic Radiographs of Brazilian Subjects: Association Between Anatomic Characteristic and Clinical Procedures

El conocimiento morfologico y topografico del canal mandibular es de suma importancia durante la realizacion de procedimientos odontologicos en la mandibula, pues las estructuras que lo recorren deben ser conservadas. El proposito del presente estudio fue realizar un analisis morfologico y morfometrico del curso y de las relaciones del canal mandibular en adultos hombres y mujeres, en dos grupos de edades distintas. La muestra fue comprendida por 300 radiografias panoramicas divididas en 4 grupos: Grupos F1 y F2: mujeres (con rangos entre 18 y 40 anos, y con mas de 40 anos de edad, respectivamente); Grupos M1 y M2: hombres (con rangos entre 18 y 40 anos, y con mas de 40 anos de edad, respectivamente). Siete medidas lineares verticales fueron realizadas en las radiografias para describir el curso del canal mandibular, y sus relaciones con las estructuras anatomicas de la mandibula. Tambien fueron evaluadas la posicion horizontal del foramen mentoniano y la relacion de proximidad entre el canal mandibular y las raices de las piezas dentarias mandibulares. Se encontraron diferencias estadisticamente significativas entre los generos en cuatro de las medidas tomadas. Sin embargo, no se encontro diferencia entre los grupos de edades para ninguna de las medidas. La posicion mas frecuente del foramen mentoniano fue entre las raices de los premolares mandibulares; y el canal mandibular mostro una relacion de proximidad con las raices del tercer molar mandibular, alejandose gradualmente de las raices de las demas piezas dentarias. Los resultados sugieren que las mediciones realizadas relacionadas al canal mandibular pueden ser influenciadas por el genero pero son independientes de la edad.

Cross-sectional study of correlation between mandibular incisor crowding and third molars in young Brazilians

Objectives: The aim of this study was to evaluate transversally the clinical correlation between lower incisor crowding and mandible third molar. Study Design: Three hundred healthy volunteers (134 male and 166 female), aged 20.4 (±2.4) years-old were submitted to a complete clinical examination and filled up a questionnaire about gender, age, total teeth number and presence or absence of superior and inferior third molar. After a recent panoramic radiography were evaluated. The multiple logistic regression showed that none of the studied factors influenced the mandibular incisor crowding. Results: The proportion of both molars present or both absent was higher than the other conditions (Chi-square, p<.0001). The multiple logistic regression showed that any of the studied factors, influenced (p>.05) the mandibular incisor crowding. Despite the statistical significance, wear orthodontics appliances showed a little correlation (odds ratios < 1.0) in the mandibular incisor crowding. Conclusion: Presence of maxillary and/or mandibular third molars has no relation with the lower incisor crowding. Key words:Malocclusion, third molars, lower incisor crowding, mandible.

Electromyographic activity assessment of individuals with and without temporomandibular disorder symptoms.

Introduction: Temporomandibular disorders (TMD) present several signs and symptoms that hinder their correct diagnosis, which is imperative on the elaboration of a treatment plan. Over the past years, several studies have been conducted to characterize and classify TMD to better understand these disorders. Therefore, the purpose of this study was to assess the electromyographic behavior of the masseter and temporal muscles in individuals with and without myogenic, arthrogenic and mixed TMD. Method: Forty volunteers of both genders responded to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC-TMD) Questionnaire, were submitted to clinical exam and underwent bilateral electromyographic exam of the masseter and temporal muscles. Results: No statistically significant difference (p>0.05) was observed during the assessment of isotonic contraction. Regarding isometric contraction, pairing between the mixed TMD group and the asymptomatic subjects did not present significant difference (p>0.05). Comparison between the myogenic and arthrogenic TMD groups and the asymptomatic group showed statistically significant difference (p<0.05). The findings of the present study demonstrated alteration on the muscle contraction pattern of TMD individuals compared to that of asymptomatic patients.

Stress Distribution in Human Zygomatic Pillar Using Three-Dimensional Finite Element Analysis

El objetivo de este articulo fue analizar la distribucion de la tension en el pilar cigomatico humano durante la contraccion del musculo masetero utilizando analisis de elementos finitos tridimensionales. Un modelo de tres dimensiones de dientes del hemicraneo facial fueron producidos sobre la base de datos de CT-scan. Se utilizo como modelo un craneo adulto de sexo masculino con la integridad de la anatomia estructural. Fuerzas musculares se aplicaron en el origen de los ascensores de los musculos de la mandibula y soportes se aplicaron a la superficie oclusal del primer y segundo molar para simular una carga masticatoria y estimular el pilar cigomatico. Condiciones de simetria se colocaron en el plano mediano. Se utilizaron restricciones en los planos superior y posterior. El analisis de las tensiones equivalentes von-Mises y maximo director se realizo a traves del campo de esfuerzos a lo largo del pilar cigomatico. Fue representada la concentracion de esfuerzos en el proceso alveolar, hueso cigomatico, proceso frontal y temporal del hueso cigomatico y el arco superciliar. La linea de tension indica la distribucion de la tension del maxilar hacia el hueso frontal y temporal. Las tensiones se produjeron debido a las fuerzas oclusales resultantes, que se apoyan principalmente por el hueso cigomatico, distribuidas de manera no uniforme y sobre todo a traves del pilar cigomatico. Este estudio ha contribuido a una mejor comprension de la distribucion de la tension en el pilar cigomatico para entender la influencia de la masticacion sobre la morfologia de este pilar y ser de utilidad en la practica clinica.