Characteristics of Mandibular Movement and Mastication in Older Adults with Removable Dental Prostheses: Three-Dimensional Analysis / Características de Movimientos Mandibulares y Masticación en Adultos Mayores con Prótesis Dental Removible: un Análisis Tridimensional

ABSTRACT: Aging is a dynamic process that includes various alterations in the oral cavity, with tooth loss being the most frequent. Rehabilitative treatment may include removable or fixed prostheses and implants. The aim of this study was to describe the geometric (trajectory, ranges, areas) and kinematic (speed) characteristics of the mandibular and masticatory movements threedimensionally in participants with dental prostheses. A sample of 10 participants with removable prosthetic rehabilitation was divided into three groups (complete, atypical and overdenture) the characteristics of mandibular movements bordering and chewing with 3D Electromagnetic Articulography were measured. The Posselt polygonin was obtained, the frontal and sagittal plans, its areas, trajectories and ranges are analyzed. The masticatory movements were analyzed in the area of each cycle, the frequency, the speed and the reason between the masticatory cycle and the bordering movements, no significant differences between the groups. Subjects with dental prostheses, regardless of the type, they showed low of motion (border and functional) compared to dentate subjects with no functional alterations whose values have been reported in the literature. The subjects with overdenture have values closer to what is described for young dentate subjects.

RESUMEN: El envejecimiento es un proceso dinámico que incluye varias alteraciones en la cavidad oral, siendo la pérdida de dientes la más frecuente. El tratamiento de rehabilitación puede incluir prótesis fijas o removibles y/o implantes. El objetivo de este estudio fue describir las características geométricas (trayectoria, rangos, áreas) y cinemáticas (velocidad) de los movimientos mandibulares y masticatorios en participantes con prótesis dentales realizando un análisis en tres dimensiones. Se consideró una muestra de 10 participantes con rehabilitación protésica y se dividió en tres grupos (prótesis total, atípica e implantosoportada), se midieron las características de los movimientos mandibulares bordeantes y masticatorios con articulografía electromagnética 3D. Se obtuvo el polígono Posselt en los planos frontal y sagital, se analizaron sus áreas, trayectorias y rangos. Se analizaron los movimientos masticatorios en cuanto al área de cada ciclo, la frecuencia, la velocidad y la razón entre el área el ciclo masticatorio y los movimientos bordeantes, sin diferencias significativas entre los grupos. Los sujetos con prótesis dentales, independientemente del tipo, mostraron disminución de movimiento (bordeante y funcional) en comparación con los sujetos dentados sin alteraciones funcionales cuyos valores se han informado en la literatura. Los sujetos con prótesis implantosoportada tienen valores más cercanos a lo que se describe para sujetos jóvenes dentados.

A Comparative Evaluation On Mandibular Movements Before And After Prosthodontic Treatment.

Background: The range of movements of mandible in Indian individuals was not studied to set a norm. The changes happening before and after prosthodontic treatment were also not studied. Aim: To determine the range of mandibular movements viz, protrusion, working side movement measured at mandibular first molar region both on the right and left sides while performing lateral excursions, non working movement measured at mandibular first molar region both on the right and left sides while performing lateral excursions, right lateral movement measured in the incisor region, left lateral movement measured in the incisor region, passive opening and active opening in normal individuals and prosthodontically treated individuals. To determine morphometric values such as intercondylar distance, distance between intercondylar axis and axis connecting mesioincisal angles of the mandibular central incisors, distance between intercondylar axis and axis connecting mesiobuccal cusps of the mandibular molars and inter mandibular molar distance related to mandible and mandibular arch of the individuals who served as sample in the above study. Material and Methods: The study was conducted on normal individuals and then on prothodontically treated individuals .The sample consisted of 160 normal individuals and 80 treated individuals. The normal individuals were divided into four according to age viz, Group I: 21-30yrs, Group II: 31-40yrs, Group III: 41-50 yrs, Group IV: 51-60 yrs. Similarly the treated individuals were divided into four according to type of treatment viz, Group A- Complete dentures, Group B-Removable partial dentures, Group C-Fixed partial dentures, Group D-single crowns. The morphometric and mandibular movement parameters were first measured in normal individuals and then in prosthodontically treated individuals with digital Vernier caliper directly and using putty index. Result and Conclusion: Conclusions drawn from the study are as follows A norm could be formulated both for morphometrics related to mandible and mandibular arch and for mandibular movements. The values obtained are relevant to individuals belonging to Bangalore and nearby areas. Opening and lateral movements can be measured directly in the incisal region using a pair of Vernier calipers. In order to measure the excursive movements in the posterior region and the protrusion in the anterior region, putty indices can be made which is a simple procedure that can be performed in a dental clinic. Prosthodontic treatment in general has a restrictive effect on mandibular movements. This observation has a limitation that the sample size is only 80. Mandibular movements can be reproduced in a computer using the graphic capabilities of coral draw. More precise data could be obtained if the inclusion of the treated individuals were restricted for the age.

Differences in opening and protrusive mandibular movements between Class I and II malocclusions in healthy adolescents / 대한치과교정학회지

OBJECTIVE: The aim of the study was to compare the opening and protrusive mandibular movements between Class I and Class II malocclusions in healthy adolescents by clinical and axiographic evaluations. METHODS: Mechanical axiography was performed on non-orthodontically treated, temporomandibular disorder (TMD)-free adolescents (12 - 16 years) with Class I (n = 38, 16 boys, 22 girls) or Class II (n = 40, 19 boys, 21 girls) malocclusion. Opening and protrusive movements were measured clinically and axiographically. Intergroup comparisons were evaluated by t-tests. RESULTS: In opening movement, the maximum clinical opening capacity was significantly different (p < or = 0.05) between the groups. In protrusive movement, the Class II group had significantly greater maximum clinical protrusion (p < 0.001) and maximum axiographic protrusive length (p < 0.01) than the Class I group. No significant difference in the other opening and protrusive axiographic measurements was observed. CONCLUSIONS: TMD-free adolescents with Class II malocclusion have increased protrusive capacity compared with TMD-free adolescents with Class I malocclusion; however, the detected differences could be normal variations during adolescence.

A computational method for recording and analysis of mandibular movements

This study proposed the development of a new clinical tool capable of quantifying the movements of opening-closing, protrusion and laterotrusion of the mandible. These movements are important for the clinical evaluation of the temporomandibular function and muscles involved in mastication. Unlike current commercial systems, the proposed system employs a low-cost video camera and a computer program that is used for reconstructing the trajectory of a reflective marker that is fixed on the mandible. In order to illustrate the clinical application of this tool, a clinical experiment consisting on the evaluation of the mandibular movements of 12 subjects was conducted. The results of this study were compatible with those found in the literature with the advantage of using a low cost, simple, non-invasive, and flexible tool customized for the needs of the practical clinic.