Comparación de la posición condilar entre dos técnicas de registro de relación céntrica mediante tomografía espiral / Condylar position comparison between two centric relation recording methods, by means of a spiral tomography technique

Objetivo: El objetivo de este estudio fue comparar la variación de la posición del cóndilo mandibular entre la técnica de registro de relación céntrica auto-inducida de tipo activa y otra de manipulación mandibular de tipo chin-point. Método: En una muestra por conveniencia de 9 sujetos (4 hombres y 5 mujeres), se estudiaron un total de 18 articulaciones témporomandibulares determinando la variación de la posición condilar con el uso de imágenes obtenidas mediante tomografía espiral, utilizando para ambas técnicas un deprogramador anterior de Neff para estandarizar el grosor del material de registro. Resultados: Se observó que con la técnica chin-point, el cóndilo adopta una posición más posterior (55.6 por ciento) y superior (72.2 por ciento) respecto a la auto-inducida de tipo activa, con diferencias estadísticamente significativas (p<0.001, t-test). En promedio se observó que la técnica chin-point produjo una magnitud de desplazamiento de 1.5mm en dirección cefálica y 1.1mm hacia posterior, tomando como referencia la posición registrada con la técnica auto-inducida de tipo activa. Conclusiones: La técnica chin-point produce una posición condilar más posterior y superior que la técnica auto-inducida de tipo activa.

Objective: The aim of this study was to compare the mandibular condylar position between two centric relation recording methods: Active self-induced type and chin-point manipulation. Method: In a convenient sample of 9 subjects (5 females and 4 males), the condylar position variation was determined in the 18 temporomandibular joints by means of a spiral tomography radiographic technique. To standardize the thickness of the registration material, a Neff anterior deprogramming appliance was used. Results: It was observed that with the chin-point technique, the condyle adopted a significantly more superior (72.2 percent) and posterior (55.6 percent) position compared to the active self-induced technique (p<0.001, t-test). Regarding magnitudes, chin-point produced an average of 1.5mm cephalic and 1.1mm posterior displacements, using the position obtained with the active self-induced technique as a reference. Conclusions: Chin-point technique generates a more superior and posterior condylar position that the one determined by the active self-induced.

Comparative study of intermaxillary relationships of manual and swallowing methods

This study compared the mandibular displacement from three methods of centric relation record using an anterior jig associated with (A) chin point guidance, (B) swallowing (control group) and (C) bimanual manipulation. Ten patients aged 25-39 years were selected if they met the following inclusion criteria: complete dentition (up to the second molars), Angle class I and absence of signs and symptoms of temporomandibular disorders and diagnostic casts showing stability in the maximum intercuspation (MI) position. Impressions of maxillary and mandibular arches were made with an irreversible hydrocolloid impression material. Master casts of each patient were obtained, mounted on a microscope table in MI as a reference position and 5 records of each method were made per patient. The mandibular casts were then repositioned with records interposed and new measurements were obtained. The difference between the two readings allowed measuring the displacement of the mandible in the anteroposterior and lateral axes. Data were analyzed statistically by ANOVA and Tukey's test at 5 percent significance level. There was no statistically significant differences (p>0.05) among the three methods for measuring lateral displacement (A=0.38 ± 0.26, B=0.32 ± 0.25 and C=0.32 ± 0.23). For the anteroposterior displacement (A=2.76 ± 1.43, B=2.46 ± 1.48 and C=2.97 ± 1.51), the swallowing method (B) differed significantly from the others (p<0.05), but no significant difference (p>0.05) was found between chin point guidance (A) and bimanual manipulation (C). In conclusion, the swallowing method produced smaller mandibular posterior displacement than the other methods.

Este estudo comparou o deslocamento mandibular a partir de 3 métodos de registro da relação cêntrica usando um jig anterior associado com: (A) guia da ponta do mento; (B) deglutição grupo controle (C) manipulação bimanual. As moldagens dos arcos maxilares e mandibulares foram feitas com hidrocolóide irreversível. Os modelos de estudo de cada paciente foram obtidos e montados em máxima intercuspidação como uma posição de referência no microscópio. Foram obtidos 5 registros de cada método em 10 pacientes. Os modelos mandibulares foram reposicionados com os registros interpostos e novas medidas foram obtidas. A diferença entre as duas leituras permitiu a medida do deslocamento mandibular nos eixos ântero-posterior e laterais. ANOVA não demonstrou diferença estatisticamente significativa entre os 3 métodos em relação ao registro do deslocamento lateral (A = 0,38 ± 0,26, B = 0,32 ± 0,25 e C = 0,32 ± 0,23). Quanto ao deslocamento anteroposterior, ANOVA e o teste de Tukey (a=0,05) indicaram diferença estatisticamente significante entre os três métodos (A=2,76 ± 1,43, B=2,46 ± 1,48 e C=2,97 ± 1,51). Não houve diferença estatisticamente significante entre A e C. A deglutição propiciou menor deslocamento mandibular posterior que os outros métodos.