Comportamiento Mecánico de un Premolar Humano Sano Sometido a Fuerzas Funcionales y Disfuncionales en un MEF / Mechanical Behavior of a Healthy Human Premolar Subjected to Functional and Dysfunctional Forces in a FEM

El propósito de este estudio fue analizar el comportamiento mecánico de la estructura dental sana de un primer premolar inferior humano sometido a fuerzas funcionales y disfuncionales en diferentes direcciones. Se buscó comprender, bajo las variables contempladas, las zonas de concentración de esfuerzos que conllevan al daño estructural de sus constituyentes y tejidos adyacentes. Se realizó el modelo 3D de la reconstrucción de un archivo TAC de un primer premolar inferior, que incluyó esmalte, dentina, ligamento periodontal y hueso alveolar considerando tres variables: dirección, magnitud y área de la fuerza aplicada. La dirección fue dirigida en tres vectores (vertical, tangencial y horizontal) bajo cuatro magnitudes, una funcional de 35 N y tres disfuncionales de 170, 310 y 445 N, aplicadas sobre un área de la cara oclusal y/o vestibular del premolar que involucró tres contactos estabilizadores (A, B y C) y dos paradores de cierre. Los resultados obtenidos explican el fenómeno de combinar tres vectores, cuatro magnitudes y un área de aplicación de la fuerza, donde los valores de esfuerzo efectivo equivalente Von Mises muestran valores máximos a partir de los 60 MPa. Los valores de tensión máximos se localizan, bajo la carga horizontal a 170 N y en el proceso masticatorio en la zona cervical, cuando la fuerza pasa del 60 %. Sobre la base de los hallazgos de este estudio, se puede concluir que la reacción de los tejidos a fuerzas funcionales y disfuncionales varía de acuerdo con la magnitud, dirección y área de aplicación de la fuerza. Los valores de tensión resultan ser más altos bajo la aplicación de fuerzas disfuncionales tanto en magnitud como en dirección, produciendo esfuerzos tensiles significativos para la estructura dental y periodontal cervical, mientras que, bajo las cargas funcionales aplicadas en cualquier dirección, no se generan esfuerzos lesivos. Esto supone el reconocimiento del poder de detrimento estructural del diente y periodonto frente al bruxismo céntrico y excéntrico.

SUMMARY: The purpose of this study was to analyze the mechanical behavior of the healthy dental structure of a human mandibular first premolar subjected to functional and dysfunctional forces in different directions. It was sought to understand, under the contemplated variables, the areas of stress concentration that lead to structural damage of its constituents and adjacent tissues. The 3D model of the reconstruction of a CT file of a lower first premolar was made, which included enamel, dentin, periodontal ligament and alveolar bone considering three variables: direction, magnitude and area of the applied force. The direction was directed in three vectors (vertical, tangential and horizontal) under four magnitudes, one functional of 35 N and three dysfunctional of 170, 310 and 445 N, applied to an area of the occlusal and/or buccal face of the premolar that involved three stabilizing contacts (A, B and C) and two closing stops. The results obtained explain the phenomenon of combining three vectors, four magnitudes and an area of force application, where the values of effective equivalent Von Mises stress show maximum values from 60 MPa. The maximum tension values are located under the horizontal load at 170 N and in the masticatory process in the cervical area, when the force exceeds 60%. Based on the findings of this study, it can be concluded that the reaction of tissues to functional and dysfunctional forces varies according to the magnitude, direction, and area of application of the force. The stress values turn out to be higher under the application of dysfunctional forces both in magnitude and in direction, producing significant tensile stresses for the dental and cervical periodontal structure, while under functional loads applied in any direction, no damaging stresses are generated. This supposes the recognition of the power of structural detriment of the tooth and periodontium against centric and eccentric bruxism.

Effect of acupuncture on the molar bite force in women with chronic neck pain / Efecto de la acupuntura sobre la fuerza de mordida en mujeres con cervicalgia crónico

Objetive: To investigate the maximum molar bite force in women with chronic neck pain after treatment with acupuncture. Materials and Methods: Twenty-three women with chronic neck pain participated. Dynamometer was used to measure the right and left maximum molar bite force. Dong Bang acupuncture needles - 0.25 mm x 30 mm was inserted into the integumentary tissue. Treatment was 10 sessions, each 30 minutes long and twice a week. Results: The right (p = 0.01) and left (p = 0.004) molar bite force was assessed after treatment with acupuncture, and showed increased occlusal strength. Conclusions: This study suggests a functional improvement in the stomatognathic system in women with chronic cervical pain after treatment with acupuncture. However, it is important to note that further research is needed to fully elucidate the long-term effects and potential clinical implications of these findings in the field of pain management and rehabilitation.

Objetivo: Investigar la fuerza masticatoria máxima en mujeres con dolor crónico de cuello después del tratamiento con acupuntura. Materiales y Métodos: Participaron veintitrés mujeres con dolor crónico de cuello. Se utilizó un dinamómetro para medir la fuerza máxima de mordida del molar derecho e izquierdo. Agujas de acupuntura Dong Bang se insertaron 0,25 mm x 30 mm en el tejido tegumentario. El tratamiento fue de 10 sesiones, cada una de 30 minutos de duración, dos veces por semana. Resultados: Se observó la fuerza de mordida del molar derecho (p=0.01) e izquierdo (p=0.004) después del tratamiento con acupuntura, que mostró un aumento de la fuerza oclusal. Conclusión: Este estudio sugiere una mejora funcional en el sistema estomatognático en mujeres con dolor cervical crónico después del tratamiento con acupuntura. Sin embargo, es importante señalar que se necesita más investigación para dilucidar por completo los efectos a largo plazo y las posibles implicaciones clínicas de estos hallazgos en el campo del tratamiento y la rehabilitación del dolor.

Evaluation of the occlusal contact area of molar dental implants comparing two different thicknesses (16 µm and 200 µm) of articulating occlusal papers and forces (200 and 250 N): a pivot in vitro study

Introduction: The goal of this pilot study was to evaluate the differences between checking occlusion on implants crowns using 16 or 200 µm thickness of articulating occlusal paper, and to compare the stained occlusal area between the groups after bite forces of 200 and 250 N. Methods: It was included 10 casts of articulated-type IV gypsum, 10 NiCr crowns, articulating occlusal papers (16 µm and 200 µm thick), and a compression test machine. Compressive forces (200 and 250 N.mm) were applied on models, to check the occlusal contact area of fixed and cemented crowns. The contact areas on the crowns were measured through images obtained by the scanning electron microscope. Statistical tests were performed considering the significant level of 5% (p≤0.05). Results: The stains found using 200 µm of articulating paper were higher than those with 16 µm, independent of the force applied. However, the stains obtained in lower teeth with different strengths (200 and 250N) marked with 16 µm articulating paper were not possible to score. The articulating paper variable had significant statistical results (p=0.002), while the variables force (p=0.443) and articulating paper-force interaction (p=0.607) were not significant. The mean area found in staining using the 200 µm and 16 µm papers was, respectively, 8.3380 mm2 and 3.4759 mm2. Conclusion: It was possible to confirm that 200 µm of articulating occlusal paper showed better and significant results to stain the occlusal area, permitting a more accurate adjustment independent of the force applied.

Study on mandibular movement trajectory and virtual occlusal pre-adjustment under light and heavy bite force / 中华口腔医学杂志

Objective: To investigate the influence of light and heavy bite force on the mandibular movement trajectories, and the influence of bite force on virtual occlusal pre-adjustment of digital full crown. Methods: From October 2021 to March 2022, 10 postgraduate volunteers (3 males and 7 females, aged 22-26 years) were recruited from Peking University School and Hospital of Stomatology. Maxillary and mandibular digital models of the participants were obtained by intraoral scanning. Jaw relations were digitally transferred under heavy bite force and mandibular movement trajectories under light and heavy bite force were recorded by jaw motion analyser. Three mandibular markers were chosen, namely the mesial proximal contact point of the central incisor (incisal point) and the mesial buccal cusp tips of the bilateral first molars. The three-dimensional displacements of the markers under two kinds of bite force in the intercuspal position (ICP), the sagittal projection of the three-dimensional displacements in the protrusive edge-to-edge position, and the coronal projection of the three-dimensional displacements in the lateral edge-to-edge position of upper and lower posterior teeth were measured. Single-sample t-test was used to compare the three-dimensional displacements and the corresponding sagittal projection and coronal projection with 0, respectively. The left maxillary central incisor and left mandibular first molar were virtually prepared by the reverse engineering software. Then dental design software was used to design digital full crown using the copy method. The mandibular movement trajectories under light and heavy bite force were separately used to guide virtual occlusal pre-adjustment. The three-dimensional deviations (mean deviations and root mean square) between the lingual surface of the left maxillary central incisor or the occlusal surface of the left mandibular first molar and that of the natural tooth before preparation were calculated (light bite force group and heavy bite force group), and the differences between the two groups were compared by the paired t-test. Results: Under the two kinds of bite force, the three-dimensional displacements of the markers in the ICP were (0.217±0.135), (0.210±0.133) and (0.237±0.101) mm, respectively; the sagittal projection of the three-dimensional displacements of the markers in the protrusive edge-to-edge position were (0.204±0.133), (0.288±0.148) and (0.292±0.136) mm, respectively; the coronal projection of the three-dimensional displacements of the mesial buccal cusp tips of the bilateral first molars in the lateral edge-to-edge position were (0.254±0.140) and (0.295±0.190) mm, respectively. The differences between the above displacements and 0 were statistically significant (P<0.05). The results of occlusal pre-adjustment showed that the mean deviations of the lingual surface of the left maxillary central incisor in the light and heavy bite force groups were (0.215±0.036) and (0.195±0.041) mm (t=3.95, P=0.004), respectively. The mean deviations of the occlusal surface of the left mandibular first molar were (0.144±0.084) and (0.100±0.096) mm (t=0.84, P=0.036), respectively. Conclusions: Both the light and heavy bite force have an influence on the mandibular movement trajectories. Virtual occlusal pre-adjustment of prostheses with mandibular movement trajectories under heavy bite force can obtain morphology of lingual or occlusal surfaces closer to the natural teeth before preparation.

Assessment of Bite Forces in Restored Teeth with Different Commonly Used Restorative Materials: A Comparative Study

ABSTRACT Objective: To evaluate and compare bite force (BF) in permanent first molars restored with glass ionomer cement (GIC), composite and amalgam, and normal contralateral permanent first molars. Material and Methods: BF was recorded in decayed permanent first molars, which were filled with GIC (n=30), composite (n=30), and amalgam (n=30), and in healthy contralateral first molars (n=90) with Force Transducer Occlusal Force Meter and compared. Results: BF was significantly higher in normal teeth on the contralateral side compared to teeth restored with GIC and composite. However, in patients with amalgam restoration, though it was less compared to that on the contralateral side, it was not statistically significant (p>0.05). Conclusion: Restoring teeth with various filling materials may improve bite force. In the present study, it was found that the teeth restored with amalgam had higher bite forces in comparison to the other restorative materials used. However, it was not comparable to that observed in the normal tooth (control) on the contralateral side.

Maximum bilateral bite strength and RMS EMG for the diagnosis of myogenic TMD

Aim: The study aimed to evaluate the accuracy of the maximum bilateral molar bite force and the Root Mean Square (RMS) Electromyography (EMG) index of the masticatory muscles in the maximum bilateral molar bite (MMBMax) of women with myogenic Temporomandibular Disorder (TMD) and asymptomatic. Methods: This is a cross-sectional study, composed of 86 women allocated to the TMD Group (n=43) and Control Group (n=43) diagnosis through the Diagnostic Criteria for Temporomandibular Disorders. The maximum bilateral molar bite force was evaluated using a bite dynamometer and the RMS EMG index of the masticatory muscles (anterior temporalis, masseter) during 5 seconds of the MMBMax task. Student t-test was used for data comparison between accuracy of the bite force and RMS EMG of masticatory muscles during the MMBMax. Results: The maximum bilateral molar bite force showed high accuracy (AUC=0.99) for the diagnosis of women with myogenic TMD and asymptomatic women, and the RMS EMG index evaluated during the MMBMax showed a moderate level of accuracy for all masticatory muscles (AUC=0.70 to 0.75). Conclusion: The bilateral bite dynamometer with a surface EMG during bilateral bite can be used to diagnose TMD in young women

Stress distribution in occlusal veneers with different finish lines when applying vertical and tangential forces / Distribución de estrés en carillas con diferentes líneas de terminación aplicando fuerzas verticales y tangenciales

Abstract To evaluate stress distribution when applying vertical and tangential forces to 1mm thick occlusal veneers with different finish lines preparations, using the finite element method. One extracted third molar was prepared for occlusal veneers, firstly without any bevel. It was scanned in order to design two groups of lithium disilicate (G1A, G2A) and composite resin (G1B, G2B) occlusal veneers. Then, the third molar preparation was modified, beveling the finish line and it was subsequently scanned again to design the occlusal veneer groups with bevel (LD: G3A, G4A and CR: G3B, G4B). The four groups were subjected to different forces (400 N vertical and 900 N tangential). At 400 N, the non-beveled veneers showed slightly higher Von Mises stress values (G1A: 783 MPa and G1B 736.5 MPa) than the beveled veneers (G3A: 685.7 MPa and G3B: 675.8 MPa). However, when 900 N tangential forces were applied, the beveled occlusal veneers showed higher Von Mises stress values (G4A: 4297 MPa and G4B: 4133 MPa) than the non-beveled occlusal veneers (G2A: 2581.1 MPa and G2B: 3519.1 MPa). Furthermore, it was observed that the tissue under the occlusal veneers with bevel showed higher Von Mises stress values than the models without any bevel. Beveled and non-beveled occlusal veneers of lithium disilicate and composite resin presented similar stress distribution values when vertical forces of 400 N were applied; whereas with tangential forces of 900 N applied near to the finish line, the beveled groups presented notably higher stress values than the non-beveled groups. However, both finish line preparations presented adequate values for possible clinical performance.

Resumen Evaluar la distribución de estrés al aplicar fuerzas verticales y tangenciales en carillas oclusales de 1mm de espesor con diferentes líneas de terminación marginal por el método de elementos finitos. Se preparó un tercer molar extraído para carilla oclusal, primero sin bisel. Se escaneó para diseñar dos grupos de carillas oclusales de disilicato de litio (G1A, G2A) y resina compuesta (G1B, G2B). Después, esta preparación molar fue modificada, biselando la línea de terminación y escaneándola nuevamente para diseñar los grupos de carillas oclusales con bisel (DL: G3A, G4A and RC: G3B, G4B). Los 4 grupos fueron sometidos a fuerzas diferentes (400 N vertical y 900 N tangencial). Con 400 N, las carillas sin bisel presentaron ligera mayor tensión de Von Mises (G1A: 783 MPa y G1B 736.5 MPa) que las carillas con bisel (G3A: 685.7 MPa y G3B: 675.8 MPa). De distinta forma, al aplicar fuerzas tangenciales de 900 N, las carillas oclusales con bisel presentaron mayor tensión de Von Mises (G4A: 4297 MPa y G4B: 4133 MPa) que las carillas oclusales sin bisel (G2A: 2581.1 MPa y G2B: 3519.1 MPa). Además, se observó que los tejidos subyacentes a las carillas oclusales con bisel, presentaron mayor tensión de Von Mises, frente a los modelos sin bisel. Las carillas oclusales con y sin bisel de disilicato de litio y resina compuesta presentaron una distribución de estrés similar con fuerzas verticales de 400 N, por otro lado, con fuerzas tangenciales de 900 N, los grupos con bisel presentaron notablemente mayor tensión que los grupos sin bisel. Sin embargo, ambos diseños de terminación marginal presentaron valores adecuados para un posible desempeño clínico.

Evaluation of molar bite force in carious and non-carious primary dentition among 4 to 6 year old children / Evaluación de la fuerza de mordida molar en dentición temporal cariada y no cariada en niños de 4 a 6 años

Objetive: The aim of the study was to evaluate the maximum molar bite force in children aged 4 to 6 years with and without dental caries. Material and Methods: This cross sectional study was carried out from May 2018 to December 2018. A total of 288 children aged between 4 to 6 years were randomly selected from six different primary schools in Chennai city, India and divided into two groups of 144 children each, based on the presence and absence of caries: Group A children with non-carious dentition and Group B children with carious dentition. Bite force measurement was performed using standardized custom made occlusal force gauge. Statistical analysis used: Data were expressed as the mean ± SD. Student's t­test (two tailed, independent) and ANOVA were used to find the significance of study parameters between the groups. Results: Occlusal bite force of non-carious dentition (367.94 ±33.71N) was higher than the carious dentition (326.73±27.83N) and it was statistically significant (p≤0.01). Overall occlusal bite force of boys (350.44±35.84N) was significantly higher than that of girls (344.22±38.25N). Flush terminal plane molar relationship showed higher occlusal bite force (380.54±27.36N) followed by mesial step (350.82±22.25N) and distal step (310.63±20.82N) molar relationship. Conclusion: Non-carious dentition showed significantly higher bite force than carious dentition in children 4 to 6 years of age. Boys had higher bite force than the girls and flush terminal plane molar relationship showed higher bite force than mesial and distal step molar relationship.

Objetivo: El objetivo del estudio fue evaluar la fuerza de mordida molar máxima en niños y niñas de 4 a 6 años con y sin caries dental. Material y Métodos: Este estudio transversal se llevó a cabo entre mayo de 2018 y diciembre de 2018. Se seleccionó aleatoriamente un total de 288 niños y niñas de entre 4 y 6 años de seis escuelas primarias diferentes en la ciudad de Chennai, India, y se dividieron en dos grupos de 144 niños cada uno según la presencia y ausencia de caries: El grupo A incluye niños con dentición no-cariada y el grupo B incluye niños con dentición cariada. La medición de la fuerza de mordida se realizó utilizando un medidor de fuerza oclusal estandarizado hecho a medida.Análisis estadístico utilizado: Los datos se expresaron como la media ± SD. Se utilizó la prueba t de Student (dos colas, independiente) y ANOVA para encontrar la importancia de los parámetros de estudio entre los grupos. Resultados: La fuerza de mordida oclusal de la dentición no cariada (367,94 ±33,71N) fue mayor que la de la dentición cariada (326,73±27,83N) y fue estadísticamente significativa (p≤0,01). La fuerza de mordida oclusal global de los niños (350,44±35,84N) fue significativamente mayor que la de las niñas (344,22±38,25N). La relación molar en el plano terminal al ras mostró una mayor fuerza de mordida oclusal (380,54 ± 27,36 N), seguida de una relación molar de escalón mesial (350,82 ± 22,25 N) y escalón distal (310,63 ± 20,82N).Conclusión: La dentición no cariada mostró una fuerza de mordida significativamente mayor que la dentición cariada en niños de 4 a 6 años de edad. Los niños tenían una mayor fuerza de mordida que las niñas y la relación molar en el plano terminal mostró una mayor fuerza de mordida que la relación molar escalonada mesial y distal.

Masticatory function according to body mass index: part II: electromyographic analysis / Función masticatoria según índice de masa corporal: parte II: análisis electromiográfico

Introduction: The objective of this study was to explore the electrical activity of the superficial muscles of mastication required to exert unilateral maximum bite force in subjects with different body mass index. Material and Methods: A cross-sectional observational study was conducted with a sample of 21 participants with an average age of 22.9 ± 3.5 years who were classified according to their body mass index, forming three study groups: normal weight (18.5-24.9), overweight (25-29.9) and obesity (≥30), with seven participants each. Through surface electromyography, the superficial muscles of mastication during right and left maximum bite force were evaluated. Results: No statistically significant differences in the maximum bite force were observed between the study groups. The data obtained from the electromyographic analysis of the superficial muscles of mastication demonstrate a trend indicating that subjects with a normal body mass index similarly activate the muscles on each side when performing a maximum bite force on a particular side, while overweight or obese subjects demonstrated significantly greater activation of the temporalis muscle associated with the side where the maximal bite force is performed. Conclusion: Our findings suggest that the maximum bite force is not influenced by body mass index and that during the performance of a maximum bite force subjects with increased body mass index present a greater activation of the temporalis muscle associated with the side where the maximum bite force was performed.

Introducción: El objetivo de este estudio fue explorar la actividad eléctrica de los músculos superficiales de la masticación, necesarios para ejercer la máxima fuerza de mordida unilateral, en sujetos con diferente índice de masa corporal. Material y Métodos: Se realizó un estudio observacional de corte transversal con una muestra de 21 participantes con una edad promedio de 22.9 ± 3.5 años, quienes fueron clasificados de acuerdo a su índice de masa corporal, formando tres grupos de estudio: peso normal (18,5-24,9), sobrepeso (25,0-29,9) y obesidad (≥30.0), con siete participantes cada uno. La electromiografía de superficie evaluó los músculos superficiales de la masticación durante la fuerza de mordida máxima derecha e izquierda. Resultados: No se observaron diferencias estadísticamente significativas en la fuerza de mordida máxima entre los grupos de estudio. Los datos obtenidos del análisis electromiográfico de los músculos superficiales de la masticación demuestran una tendencia que indica que los sujetos con un índice de masa corporal normal activan de manera similar los músculos de cada lado cuando ejercen la fuerza de mordida máxima en un lado en particular. mientras que los sujetos con sobrepeso u obesos demostraron una activación significativamente mayor del músculo temporal asociado con el lado donde se realiza la fuerza máxima de mordida. Conclusión: Nuestros hallazgos sugieren que la fuerza de mordida máxima no está influenciada por el índice de masa corporal y que durante la realización de una fuerza de mordida máxima los sujetos con índice de masa corporal aumentado presentan una mayor activación del músculo temporal asociado al lado donde se realizó la fuerza de mordida máxima.

El odontólogo, custodio de la función masticatoria / The dentist, guardian of masticatory function

La masticación tiene como objetivo la adecuada preparación de los alimentos para su deglución y digestión. Cualquier alteración en el sistema estomatognático puede deteriorar la masticación. El odontó- logo es el profesional responsable de mantener y/o restaurar la función masticatoria. La evaluación de la función masticatoria puede hacerse de forma subjetiva utilizando cuestionarios para medir la percepción del paciente sobre su capacidad masticatoria o de forma objetiva analizando la fuerza oclusal, la actividad electromiográfica de los músculos mas- ticadores, la trayectoria de la mandíbula al masticar o la capacidad de trituración de los alimentos. Estos métodos se utilizan en proyectos de investigación, pero en la clínica ¿evaluamos si existe alguna alteración al masticar y al finalizar el tratamiento si cumplimos con el objetivo de restaurar la función masticatoria? ¿Realmente nos preocupamos por mantener y/o restaurar la función masticatoria? Por lo general no, ni en los consultorios, ni en las clínicas universitarias. Es esencial que nos concienticemos de nuestra responsabilidad y para ello es necesario que se le dé mayor peso curricular a la función masticatoria y cómo evaluarla. Seamos realmente custodios de la función masticatoria de nuestros pacientes (AU)

The goal of chewing is to properly prepare food for swallowing and digestion. Any problem in the stomatognathic system can deteriorate chewing. The professional responsible of maintaining and/or restoring masticatory function is the dentist. Masticatory function can be evaluated subjectively through questionnaires to measure the patient's perception of his/her masticatory capacity or objectively analyzing occlusal force, the electromyographic activity of the masticatory muscles, the movements of the mandible during chewing or the individual's capacity to breakdown food. These methods are used in research projects but, do we examine if there is any problem during chewing and if we are achieving our goal of restoring masticatory function at the end of the treatment in our offices? Do we really focus on maintaining and/or restoring masticatory function? Not truly, not in our offices or university clinics. It is imperative that we acknowledge our responsibility but for that it is essential that masticatory function and how to evaluate it is given more weight in the curriculum. Let us be genuine guardians of the masticatory function of our patients (AU)

Função mastigatória nos diferentes ciclos de vida: análise eletromiográfica / Chewing function in different life cycles: analysis with electromyography / Función masticatoria en diferentes ciclos de vida: análisis con electromiografía

Introdução: A mastigação tem uma importância significativa para o desenvolvimento das estruturas do Sistema Estomatognático (SE), sendo esta aperfeiçoada no decorrer da vida. A eletromiografia de superfície destaca-se como uma importante ferramenta de avaliação capaz de quantificar a atividade elétrica dos músculos mastigatórios, sendo uma forma de caracterizar o comportamento dessa função estomatognática. Observando a complexidade e importância da mastigação, torna-se importante conhecer melhor as modificações desta função no decorrer dos ciclos de vida. Objetivo: O objetivo do estudo foi realizar análise eletromiográfica dos músculos da mastigação em indivíduos sem queixas orofaciais representantes dos ciclos da infância, adolescência, fase adulta e senescência. Método: A amostra foi composta por 120 voluntários de ambos os sexos, distribuídos em quatro grupos de acordo com a faixa de idade. Os voluntários foram submetidos à avaliação da mastigação por meio da eletromiografia de superfície durante o repouso, contração voluntária máxima, mastigações unilaterais direita e esquerda e mastigação habitual; bem como a verificação da força de mordida entre os dentes incisivos centrais, molares do lado direito e molares do lado esquerdo. Realizou-se, ainda, a tomada de medidas antropométricas faciais das hemifaces direta e esquerda dos voluntários. Resultados: Os resultados apontaram comportamentos morfológicos e funcionais distintos entre os grupos estudados, bem como a influência da variável sexo nas respostas eletrofisiológicas da função mastigatória. Conclusão: foi verificado que o comportamento mastigatório variou segundo a idade e o sexo, apontando uma tendência de correlação entre os componetes anatômicos e funcionais envolvidos nessa função estomatognática.

Introduction: Chewing is of significant importance for the development of the structures of the Stomatognathic System (SE), which is improved throughout life. Surface electromyography stands out as an important assessment tool capable of quantifying the electrical activity of the masticatory muscles, being a way to characterize the behavior of this stomatognathic function. Observing the complexity and importance of chewing, it is important to better understand the changes in this function during the life cycles. Objective: The objective of the study was to perform an electromyographic analysis of the muscles of mastication in individuals without orofacial complaints representing the cycles of childhood, adolescence, adulthood and senescence. Method: The sample consisted of 120 volunteers of both sexes, distributed in four groups according to the age group. The volunteers underwent chewing assessment by means of surface electromyography during rest, maximum voluntary contraction, unilateral right and left chewing and habitual chewing; as well as the verification of the bite force between the central incisor teeth, molars on the right side and molars on the left side. Facial anthropometric measurements of the direct and left hemifaces of the volunteers were also taken. Results: The results showed distinct morphological and functional behaviors between the groups studied, as well as the influence of the gender variable on the electrophysiological responses of the masticatory function. Conclusion: it was found that the masticatory behavior varied according to age and sex, pointing to a trend of correlation between the anatomical and functional components involved in this stomatognathic function.

Introducción: La masticación es de gran importancia para el desarrollo de las estructuras del Sistema Estomatognático (SE), que se mejora a lo largo de la vida. La electromiografía de superficie se destaca como una importante herramienta de evaluación capaz de cuantificar la actividad eléctrica de los músculos masticatorios, siendo una forma de caracterizar el comportamiento de esta función estomatognática. Observando la complejidad de esta función, es importante conocer mejor los cambios de esta función durante los ciclos de vida. Objetivo: El objetivo del estudio fue realizar un análisis electromiográfico de los músculos de la masticación en individuos sin quejas orofaciales representando los ciclos de niñez, adolescencia, adultez y senescencia. Método: La muestra estuvo formada por 120 voluntarios de ambos sexos, distribuidos en cuatro grupos según el grupo de edad. Los voluntarios fueron sometidos a valoración masticatoria mediante electromiografía de superficie en reposo, máxima contracción voluntaria, masticación unilateral derecha e izquierda y masticación habitual; así como la verificación de la fuerza de mordida entre los incisivos centrales, molares del lado derecho y molares del lado izquierdo. También se tomaron medidas antropométricas faciales de los hemifaces directo e izquierdo de los voluntarios. Resultados: Los resultados mostraron distintos comportamientos morfológicos y funcionales entre los grupos estudiados, así como la influencia de la variable género en las respuestas electrofisiológicas de la función masticatoria. Conclusión: se encontró que el comportamiento masticatorio varió según la edad y el sexo, apuntando a una tendencia de correlación entre los componentes anatómicos y funcionales involucrados en esta función estomatognática.

Efeitos de customizações da prótese total mandibular sobre a qualidade de vida, força de mordida e eletromiografia de músculos da mastigação de pacientes edêntulos: um estudo clínico analítico intervencional / Effects of mandibular complete denture customizations on quality of life, bite force, and masticatory muscle electromyography in edentulous patients: an interventional analytical clinical study

Objetivo: Avaliar se customizações da prótese total mandibular (reembasamento e restabelecimento da dimensão vertical de oclusão) influenciam na amplitude eletromiográfica dos músculos masseter e temporal, força máxima de mordida e qualidade de vida relacionada à saúde oral de indivíduos edêntulos. Materiais e métodos: Usuários de próteses totais que usavam o mesmo par de próteses por mais do que 5 anos foram incluídos (sem disfunção temporomandibular) (n=15). Avaliações de qualidade de vida (Oral Health Impact Profile for Edentulous ­ OHIP-EDENT), força máxima de mordida, e eletromiografia dos músculos masseter e temporal foram realizadas em 5 tempos diferentes (T1 ­ próteses antigas originais; T2 ­ após 18 dias de uso da prótese mandibular reembasada; T3 ­ após 18 dias do restabelecimento da dimensão vertical de oclusão; e T4 e T5 ­ 30 e 100 dias de uso de novas próteses totais. Resultados: Não houve diferenças significativas entre os pontos de tempo para todos os testes eletromiográficos e de força máxima de mordida. O OHIP-EDENT mostrou que o reembasamento pode contribuir para uma maior adaptação da prótese total mandibular e conforto do paciente (T2), em contrapartida T3 foi associado com o desconforto do paciente (p<0.05). Conclusão: Baseado na avaliação de qualidade de vida relacionada à saúde oral, o reembasamento da prótese total mandibular ocasionou um aumento do conforto mastigatório para os pacientes, e o restabelecimento prévio da dimensão vertical de oclusão causou um desconforto para os pacientes. A amplitude eletromiográfica mostrou que as customizações realizadas neste estudo não aumentaram ou diminuíram o esforço mastigatório significativamente. Além disso, todos os valores de força máxima de mordida observados estavam dentro do clinicamente aceitável(AU)

Objective: To evaluate whether customizations of mandibular complete dentures (relining and restoration of the vertical dimension of occlusion) influence the electromyographic amplitude of the masseter and temporal muscles, maximum bite force and oral health-related quality of life of edentulous individuals. Materials and methods: Complete denture wearers who wore the same pair of dentures for more than 5 years were included (without temporomandibular dysfunction) (n=15). Assessments of quality of life (Oral Health Impact Profile for Edentulous ­ OHIP-EDENT), maximum bite force, and electromyography of the masseter and temporal muscles were performed at 5 different times (T1 - original old dentures; T2 - after 18 days of wearing relined mandibular denture; T3 - after 18 days of restoration of the vertical dimension of occlusion; and T4 and T5 - 30 and 100 days of wearing new complete dentures. Results: There were no significant differences between the time points for all electromyographic and maximum bite force tests. The OHIP-EDENT showed that relining can contribute to greater adaptation of the mandibular denture and patient comfort (T2), in contrast, T3 was associated with patient discomfort (p<0.05). Conclusion: Based on the assessment of quality of life related to oral health, the reline of the mandibular complete denture caused an increase in masticatory comfort for the patients, and the previous definitive restoration of the vertical dimension of occlusion caused discomfort for patients. The electromyographic amplitude showed that the customizations performed in this study did not significantly increase or decrease masticatory effort. In addition, all observed maximum bite force values were within the clinically acceptable range(AU)

Confección de prótesis de carga inmediata mediante barras articuladas: componentes, modo de uso y longitud de la barra en función de la localización / Fabrication of immediately loaded prostheses using articulated bars: components, method of use and bar length depending on the location

En la implantología actual, la confección de prótesis de carga inmediata se ha convertido en un procedi-miento de rutina. Contar con elementos pre-formados con un correcto ajuste al implante o transepitelial so-bre el que se trabaja, minimiza el tiempo de trabajo sin renunciar a la eficiencia. En el presente trabajo se muestran elementos preformados articulados para la realización de prótesis de carga inmediata y su forma de uso, así como un análisis biomecánico de las estructuras para conocer su repercusión en las distintas fuerzas recibidas durante la masticación. Resultados: Al aplicar la carga en la zona central de la barra (paralela a los implantes), la tensión máxima recibida en la zona correspondiente al extremo de la barra sufre variaciones importantes, desde 128 Mpa en la longitud de 13 mm hasta un máximo de 391 Mpa (megapascales) en la longitud de 5 mm, siendo la ten-sión máxima, media para todas las medidas, de 242 Mpa (+/-96,76). En el ensayo de las diferentes medi-das de la barra se observa también una tensión cre-ciente para longitudes de barra a partir de 7 mm, al aplicar la tensión en la zona media de la estructura, por lo que longitudes entre 5 y 7 mm pueden consi-derarse prácticamente con la misma distribución de tensiones hacia los extremos y en la zona de unión. En conclusión, las barras articuladas son un elemento de confección de prótesis provisionales de carga in-mediata de gran utilidad, que pueden confeccionarse de forma rápida y generan un comportamiento bio-mecánico predecible (AU)

In current implantology, the fabrication of immediately loaded prostheses has become a routine procedure. Being able to have pre-formed elements with a correct fit to the implant or transepithelial on which we are working minimizes working time without sacrificing efficiency. Material and methods: We show articulated preformed elements for immediate loading prostheses and how they are used, as well as a biomechanical analysis of the structures to determine their repercussion on the different forces received during mastication. Results: When the load is applied in the central area of the bar (parallel to the implants) the maximum stress received in the area corresponding to the end of the bar undergoes significant variations, from 128 Mpa in the 13 mm length to a maximum of 391 Mpa in the 5 mm length, the average maximum stress for all the measurements being 242 Mpa (+/-96.76). In the test of the different bar sizes we can also observe an increasing stress for bar lengths from 7 mm onwards when applying the stress in the middle zone of the structure, so that lengths between 5 and 7 mm can be considered to have practically the same stress distribution towards the ends and in the joint zone. Conclusions: Hinged bars are a very useful fabrication element for immediately loaded provisional prostheses, which can be fabricated quickly and generate a predictable biomechanical behavior (AU)

Resistencia a la fuerza de tracción de espigos de fibra de vidrio y anatomizados / Tensile bond strength of fiberglass and anatomized posts

Introducción: Es frecuente el desprendimiento de los espigos de fibra de vidrio por pérdida de adhesión cuando son sometidos a las fuerzas masticatorias. Objetivo: Comparar in vitro la resistencia a las fuerzas de tracción de espigos de fibra de vidrio y anatomizado con un mismo cemento. Métodos: Estudio in vitro, de tipo experimental. Se seleccionaron 20 premolares extraídos por motivos ortodónticos que fueron distribuidos aleatoriamente en dos grupos. Se les realizó el tratamiento de conductos por un especialista, la preparación fue manual y la técnica de obturación por condensación lateral. Los dientes fueron preparados para, en forma estándar, recibir el espigo de fibra de vidrio y anatomizados con resina. Para ambos grupos la cementación siguió el protocolo sugerido por el fabricante de Allcem Core® (cemento dual). Los especímenes fueron troquelados en acrílico de autocurado. Para luego ser sometido a fuerza de tracción vertical en la máquina de pruebas de materiales (Instrom©). Resultados: En el grupo de dientes con espigos anatomizados se obtuvo una media de 31 Kg/F, postes de fibra de vidrio 12,47 Kg/F. Según las pruebas de Shapiro-Wilk, las muestras presentaron distribución normal (p > 0,05). Se contrastó la hipótesis con la prueba de t de Student y se encontró diferencia estadística altamente significativas entre los grupos (p = 0,001) Conclusiones: Existe una mayor resistencia a la tracción vertical en los espigos anatomizados(AU)

Introduction: Fiberglass posts often fall off their position due to loss of adhesive capacity when they are subjected to masticatory force. Objective: Compare in vitro the tensile bond strength of fiberglass and anatomized posts cemented with the same adhesive material. Methods: An in vitro experimental study was conducted. A selection was made of 20 premolars extracted by orthodontic indication which were then randomly distributed into two groups. The premolars underwent root canal treatment by a specialist. The preparation was manual and sealing was performed by lateral condensation. The teeth were prepared in the standard manner to receive the fiberglass and resin-anatomized posts. In both groups' cementation followed the protocol suggested by the manufacturer of Allcem Core® (dual cement). The specimens were stamped in self-curing acrylic. Next, they were subjected to vertical tensile strength in an materials testing machine (Instrom©). Results: The mean values obtained were 31 kg/F for teeth with anatomized posts and 12.47 kg/F for fiberglass posts. According to Shapiro-Wilk tests, the samples exhibited a normal distribution (p > 0.05). The hypothesis was contrasted with Student's t test, obtaining a highly significant statistical difference between the groups (p = 0.001). Conclusions: Vertical tensile bond strength is greater in anatomized posts(AU)

Reabilitação implantossuportada pela técnica "All on four" após periimplantite mandibular: relato de caso / Implant rehabilitation supported by the "All on four" technique after mandibular periimplantitis: case report

Com o avanço da odontologia, os implantes dentários tornaram-se cada vez mais atrativos por oferecerem um melhor conforto, estética e função mastigatória. Todavia, com o aumento da sua utilização também surgiram os problemas, dentre eles a periimplantite. Vista como uma doença irreversível de caráter inflamatório, ela afeta os tecidos ao seu redor, levando à perda. No contexto da Implantodontia, os implantes dentários são afetados pela periimplantite - quando instalada - o que induz à destruição dos tecidos de suporte e proteção adjacentes, ocasionando também a perda destas reabilitações. Portanto, novas reabilitações devem ser planejadas para que possam corrigir os defeitos causados pela doença. Dentre as opções, a técnica "All on four" apresenta-se como vantajosa, po dendo ser escolhida para grandes reabilitações. Logo, o presente artigo tem o objetivo de descrever um caso clínico utilizando a técnica "all on four" que reabilitou um paciente edêntulo em mandíbula, na qual possuía implantes afetados pela periimplantite, optando-se pela remoção e nova instalação de 4 implantes pela técnica escolhida. Após 4 meses, foi realizada a instalação da prótese definitiva... (AU)

With the advancement of dentistry, dental implants have become increasingly attractive as they offer bet ter comfort, aesthetics and masticatory function. However, with the increase in its use, problems also arose, among them the peri-implantitis disease. Seen as an irreversible disease with an inflammatory character, it affects the tissues around it, leading to loss. In the context of Implantology, dental implants are affected by peri-implantitis - when installed - which induces the destruction of adjacent support and protective tissues, also causing the loss of these rehabilitations. Therefore, new rehabilitation must be planned so that they can correct the defects caused by the disease. Among the options, the "All on four" technique presents itself as an advantage and can be chosen for major rehabilitation. Therefore, the present article aims to describe a clinical case using the "all on four" technique that rehabilitated an edentulous patient in the mandible, in which he had implants affected by peri-implantitis, opting for the removal and new installation of 4 implants by the technique chosen. After 4 months, the definitive prosthesis was installed... (AU)

Síndrome da apneia obstrutiva do sono em crianças (SAOS) associada aos dispositivos ortopédicos orais hyrax e bionator de balters sobre respostas miofuncionais / Obstructive sleep apnea syndrome in children (OSAS) associated with Hyrax and Balters' Bionator oral orthopedic devices on myofunctional responses

O objetivo deste estudo foi avaliar a influência terapêutica dos dispositivos orais Hyrax e Bionator de Balters no tratamento da Síndrome da Apneia Obstrutiva do Sono (SAOS), sobre a melhora da SAOS observado pela polissonografia, atividade elétrica dos músculos masseter e temporal, força máxima de mordida, qualidade de vida, e diâmetro dos pontos cefalométricos. Foram selecionados 11 participantes de ambos os sexos, diagnosticados com SAOS através do exame polissonográfico tipo III e com necessidade de tratamento ortopédico facial. Foi feita a coleta dos dados, os responsáveis preencheram os questionários (Escala de Distúrbios do Sono em Crianças e OSA-18-PV), termo de consentimento livre e esclarecido aos responsáveis e para as crianças, documentação ortodôntica (incluindo a análise do diâmetro dos pontos cefalométricos - espaço nasofaríngeo anterior e posterior (NFA-NFP), assim como espaço bucofaríngeo anterior e posterior (BFA-BFP)), análises iniciais da eletromiografia dos músculos masseter e temporal e força máxima de mordida. Estas informações foram coletadas no início do tratamento e após 11 meses, assim como o exame polissonográfico tipo III. Os dados foram normalizados pelo apertamento com Parafilm M e submetidos à análise normalidade pelo teste de Kolmogorov-Smirnov, sendo observado os dados: valor de polissonografia; eletromiografia de masséter direito e esquerdo; eletromiografia de temporal direito e esquerdo; força de mordida em região de incisivo e molar esquerdo/direito, os questionários foram avaliados através de score e nota (0-10), e cefalometria (análise das distâncias NFA-NFP e BFABFP). Para estes dados, foi realizado o teste t de Student. Para os dados com distribuição não normal, foi realizado o teste de Wilcoxon. Todas as análises foram realizadas com nível de significância de 5%. Em relação ao exame polissonográfico e os questionários, houve diferença estatística evidenciando melhora na qualidade do sono dos indivíduos. A eletromiografia demonstrou que houve diferença estatística em repouso no músculo temporal direito, e na mastigação de uva passas, nos músculos masseter e temporal do lado direito. Na cefalometria, foi observada diferença estatística na distância entre os pontos NFA-NFP. Conclui-se que o uso dos dispositivos Hyrax e Bionator de Balters em crianças classe II e portadoras da SAOS é uma alternativa de tratamento segura e eficaz(AU)

The aim of the study was to evaluate the influence of oral devices Hyrax and Balters Bionator in the treatment of Obstructive Sleep Apnea Syndrome (OSAS), on the improvement of OSAS observed by polysomnography, electrical activity of the masseter and temporal muscles, maximum bite force, quality of life, and diameter of cephalometric points. Eleven participants of both genders, diagnosed with OSAS through type III polysomnographic examination and in need of facial orthopedic treatment, were selected. Data collection was performed, the guardians filled out the questionnaires (Sleep Disorders Scale in Children and OSA-18-PV), informed consent form to guardians and for children, cephalometric orthodontic documents - nasopharyngeal space anterior and posterior (NFA-NFP), as well as anterior and posterior buccopharyngeal space (BFA-BFP)), initial analysis of the electromyography of the masseter and temporal muscles and maximum bite force. This information was collected at the beginning of treatment and after 11 months, as well as the type III polysomnographic exam. Data were normalized by tightening with Parafilm M and analysis of normality using the Kolmogorov-Smirnov test, observing the following data: polysomnography value; right and left masseter electromyography; right and left temporal electromyography; bite force in the left/right incisor and molar region, the questionnaires were obtained through score and grade (0-10), and cephalometry (analysis of the NFA-NFP and BFA-BFP distances). For these data, the Student test was performed. For data with non-normal distribution, the Wilcoxon test was performed. All analyzes were performed with a significance level of 5%. Regarding the polysomnographic exam and the questionnaires, there was a statistical difference showing an improvement in the sleep quality of the respondents. The electromyography required that there was a statistical difference at rest in the right muscle, and when chewing raisins, in the masseter and temporal muscles on the right side. In cephalometry, a statistical difference was observed in the distance between the NFA-NFP points. It can be concluded that the use of the Balters Hyrax and Bionator devices in class II children and children with OSAS is a safe and effective treatment alternative(AU)

Generation I and Generation II Elastomeric Chains Characteristics Comparison in Artificial Saliva Immersion / Comparação das Características dos Elásticos Ortodônticos tipo Corrente de Geração I e Geração II em Imersão em Saliva Artificial

Objective: To determine the force decay and discoloration in Generation I and Generation II elastomeric chain on artificial saliva immersion. Material and methods: Generation I and Generation II elastomeric chains stretched on an acrylic board and immersed in artificial saliva for 1, 7, 14, 21, and 28 days according to the group of days. On each specified day, the force of each sample measured by an orthodontic force gauge and the magnitude of the force obtained is entered to the formula to find out the force decay in percentage, whereas discoloration of each sample analyzed by the color reader with CIE Lab analysis. Results: The force decay between Generation I and Generation II elastomeric chains showed a statistically significant difference in every group of days, in which Generation II is more effective in maintaining stretch force. Similar to force decay, the discoloration in Generation I elastomeric chains on the 14th day showed significant value and Generation II elastomeric chains were more stable in maintaining color compared to Generation I. Conclusions: over the entire research period time, Generation II elastomeric chains are more stable in maintaining stretch forces and color compared to Generation I elastomeric chains. (AU)

Objetivo: Determinar a queda de força e descoloração nos elásticos ortodônticos tipo corrente de Geração I e Geração II na imersão em saliva artificial. Material e métodos: Elásticos Geração I e Geração II foram esticados em placas de acrílico e imersas em saliva artificial por 1, 7, 14, 21 e 28 dias, de acordo com o grupo de dias. Em cada dia especificado, a força de cada amostra medida por um medidor de força ortodôntica e a magnitude da força obtida são inseridos na fórmula para descobrir sua queda em porcentagem, enquanto a descoloração de cada amostra foi analisada pelo leitor de cores "CIE Lab". Resultados: A queda da força entre os elásticos Geração I e Geração II apresentou diferença estatisticamente significativa em todos os grupos de dias, sendo que a de Geração II foi mais efetiva na manutenção da força de alongamento. Semelhante à queda de força, a descoloração nos elásticos da Geração I mostrou um valor significativo no 14º dia, e elásticos da Geração II foram mais estáveis na manutenção da cor em comparação com a Geração I. Conclusões: durante todo o período de pesquisa, os elásticos tipo corrente da Geração II foram mais estáveis na manutenção das forças de alongamento e da cor em comparação com os elásticos da Geração I (AU)

Evaluation of bite force and masticatory performance: complete denture vs mandibular overdenture users

Abstract: This cross-sectional observational study with 24 patients evaluated differences in bite force (BF) and masticatory performance (MP) between conventional complete denture (CCD) and implant mandibular overdenture (IMO) users and the correlation between these variables. The BF test was performed bilaterally with an occlusal force device. During the MP test, patients were asked to chew Optocal particles for 40 cycles. The Shapiro Wilk test was employed to verify the normality of the data, the student t test to identify differences between groups, and Pearson's correlation to investigate interrelationships between variables. A multiple linear regression was subsequently performed via the stepwise method. P values ≤0.05 were considered statistically significant. Unlike IMO users, CCD users presented a significant difference (25.6%) in BF between the dominant and non-dominant chewing side (p=0.04). IMO users presented significantly higher BF (p=0.01) without presenting a dominant side (p=0.38), and also performed significantly better for the following MP parameters: MPX50 values decreased by 27.25% in IMO users (p=0.01), MPB decreased by 48.38% (p=0.01), and ME 5.6 decreased by 53.25% (p=0.02), while ME2.8 increased by 151.57% (p=0.01). The BF and MPX50 in the IMO wearers group were negatively correlated (-0.57; p=0.05); this correlation coefficient was the only parameter included in the multivariate regression model. IMO users have higher BF and better masticatory performance than CCD users, especially in terms of chewed particles size reduction. MP is correlated with a higher BF in IMO users through better particle trituration.

Resumo Este estudo observacional transversal com 24 participantes teve como objetivo avaliar as diferenças na força de mordida (FM) e na PM (performance mastigatória) entre usuários de prótese total convencional (PTC) e de overdenture mandibular (OM) e a correlação entre essas variáveis. O teste de FM foi realizado bilateralmente com um dispositivo de força oclusal. Durante o teste de PM, os pacientes foram solicitados a mastigar uma porção padronizada de Optocal por 40 ciclos mastigatórios. O teste de Shapiro Wilk foi empregado para verificar a normalidade dos dados, o teste T de Student para identificar diferenças entre os grupos e os coeficientes de correlação de Pearson para investigar inter-relações entre variáveis. Uma regressão linear múltipla foi realizada pelo método stepwise. Valores de p≤0,05 foram considerados estatisticamente significantes. Diferentemente dos usuários de OM, os usuários de PTC apresentaram uma diferença significativa (34%) na FM entre o lado dominante e o não dominante (p=0,04). Os usuários de OM apresentaram FM significativamente maior (p=0,01) sem apresentar um lado dominante (p=0,38) e obtiveram PM significativamente melhor nos seguintes parâmetros: os valores de PMX50 diminuíram 27,25% (p=0,01), PMB diminuiu em 48,38% (p=0,01), e EM 5.6 diminuiu 53,25% (p=0,02), enquanto EM2.8 aumentou 151,57% (p=0,01). A FM e PMX50 no grupo de usuários da IMO foram negativamente correlacionados (-0,57;p=0,05); esse coeficiente de correlação foi o único parâmetro incluído no modelo de regressão multivariada. Os usuários da OM possuem maior FM e melhor performance mastigatória do que os usuários de PTC, observados principalmente na redução do tamanho das partículas mastigadas. A PM está correlacionada com um maior FM nos usuários da OM através de uma melhor trituração de partículas.

Factores morfofuncionales de interés en prostodoncia que dependen de los biotipos craneofaciales / Morphofunctional factors of interest in prosthodontics depending on the craniofacial biotypes

El presente es un trabajo de investigación bibliográfica que busca establecer la posibilidad de utilizar las cefalometrías como elementos de diagnóstico pronóstico y elaboración de prótesis. Centra su objeto de estudio en encontrar y clasificar los factores morfológicos y funcionales que varían con los biotipos craneofaciales y que son de interés en la prostodoncia. La metodología empleada fue la revisión de la literatura histórica hasta la actualidad en la que se relacionan temas de prostodoncia a los biotipos craneofaciales. Si bien solo dos autores relacionaron la prostodoncia con los biotipos cráneo faciales, sí se encontraron varios temas de interés asociados directamente a la prostodoncia. Se clasificaron en temas de oclusión: Curva de Spee, plano de oclusión, movimientos mandibulares, dimensión vertical oclusiva y de especio libre interoclusal. Tema de maloclusiones. Tema de fuerza muscular. Tema variaciones morfológicas de procesos alveolares, corticales ósea y de la forma dentaría. Encontrándose para cada uno de ellos alguna correlación positiva con los distintos tipos faciales. De este estudio, se concluye que es necesario sistematizar el estudio de los conocimientos que puede aportar la cefalometría como una importante herramienta de diagnóstico al prostodoncista a partir de haberse encontrado variaciones muy importantes en los aspectos mencionados que hacen al interés de la rehabilitación prostodóncica (AU)

This Work is a bibliographic research that seeks to establish the use of cephalometries as elements of diagnosis prognostic and prosthesis elaboration. Its focus is to find and classify morphological and functional factors that vary with facial types which are of interest in prosthodontics. This was a review of the historical literature to date, in which prosthodontics are related to facial types. Although only two authors related prosthodontics to facial ypes, they did find several topics of interest directly associated with prosthodontics. They were classified into occlusion themes: Spee curve, occlusion plane, mandibular movements, occlusive vertical dimension and interocclusal free space. Malocclusion issue. Muscle strength theme. Morphological variations of alveolar processes, cortical bone and dental morphology. They found some positive correlation with the different facial types for each of them. From this study, it is concluded that it is necessary to systematize the study of cephalometries because they can provide to be an important diagnostic tool to the prosthodontist because there were found very important variations in the mentioned aspects that are of interest in prosthodontic rehabilitation (AU)

Assessment of Maximum Bite Force in Oral Submucous Fibrosis Patients: A Preliminary Study

Abstract Objective: To determine the maximum bite force (MBF) in oral submucous fibrosis (OSMF) patients and to compare them with that of healthy subjects. Material and Methods: Twenty patients who were clinically confirmed, as OSMF and 20 healthy controls matched for age, gender, and number of intact functional teeth were included in this study. For each subject, age, gender, weight, height and body mass index (BMI) were recorded. The MBF registration was carried out by the two evaluators, who were previously calibrated. Bite force was measured in the first molar region using a force transducer occlusal force meter for each subject seated at the upright position, with Frankfort's plane nearly parallel to the floor, and no head support. The Student's independent t-test was used to determine the statistical significance in relation to mean height, weight, BMI and the presence of number of intact teeth and MBF between the healthy subjects and OSMF individuals. A comparison of grades of OSMF with all variables was carried out by one-way ANOVA test. Results: No significant difference was found in mean age, mean height, weight, BMI and the presence of the number of intact teeth between healthy individuals and OSMF patients. The mean MBF in healthy subjects was 628.23 ± 24.39 N and 635.47 ± 31.22 N in OSMF patients. Even though the healthy subjects reported a higher MBF than OSMF patients did, the difference was statistically non-significant. With regards to sides, no significant difference was observed in mean MBF in healthy subjects and OSMF patients on the right (p=0.7818) and left side (p=0.6154). Conclusion: The healthy subjects reported higher MBF values than OSMF patients did and the difference was statistically non-significant.