RESUMEN
AIMS: To determine whether sex differences exist in tissue oxygen saturation (StO2) and the hemoglobin (Hb) oxygenation state of the resting human masseter muscle. METHODS: Near-infrared spectroscopy (NIRS) was used to measure StO2 and Hb oxygenation state in 20 healthy adult volunteers (10 women and 10 men). To determine the measurement range and reliability of the NIRS recording probe, the probe was set up on 12 layers of white acrylic resin plate, each 3 mm thick. Total hemoglobin levels were measured while a red vinyl resin plate, 1 mm thick, was inserted in turn between each of the 12 layers. Distances from the skin surface to the lateral surface (S-L) and to the medial surface (S-M) of the right masseter at the middle portion of the masseter were measured on T1-weighted magnetic resonance images (repetition time 500 ms, echo time 23 ms). Thickness of the masseter was calculated by subtraction [(S-M)--(S-L)]. For the study of Hb oxygenation state, the probe was positioned at the same position on the skin surface at the mandibular postural (rest) position. RESULTS: The measurement range of the NIRS probe was from 9 to 21 mm under the skin, and the reliability of the probe was judged by intra- and inter-class correlation coefficients. There was no sex difference in S-L and the thickness of the masseter; the means of S-L and masseter thickness were 9.3 mm and 15.5 mm in men and 9.8 mm and 14.3 mm in women, respectively. Except for StO2 values, there were significant sex differences in the Hb oxygenation parameters, with the mean values in the men being approximately twice those in the women. CONCLUSION: These results provide evidence that a sex difference in the Hb oxygenation state may exist in the masseter muscle of normal healthy subjects.
Asunto(s)
Hemoglobinas/metabolismo , Músculo Masetero/metabolismo , Consumo de Oxígeno/fisiología , Oxígeno/sangre , Caracteres Sexuales , Adulto , Análisis de Varianza , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Músculo Masetero/irrigación sanguínea , Variaciones Dependientes del Observador , Probabilidad , Flujo Sanguíneo Regional/fisiología , Reproducibilidad de los Resultados , Espectroscopía Infrarroja Corta , Estadística como Asunto , Técnica de Sustracción , Dimensión VerticalRESUMEN
To clarify the relationship between the temporal component of the temporomandibular joint and facial bone structure, we measured anthropologic craniometric points and the structure of the mandibular fossa, including the eminence in 33 Japanese male dry skulls, with a three-dimensional apparatus. The length from the articular tubercle to the medial glenoid tubercle is correlated with skeletal variables such as the length of the fossae, the width of the masseter origin, and the mandibular length. Therefore it appears that the frontal dimension is related to the facial development, which is attributable to bite force. Goniometrically, the angle between the line deepest point of the fossa--the midpoint of the eminence and the Frankfort horizontal plane (middle angle)--was negatively correlated only with the ANB angle, suggesting that a steeper middle angle of the eminence is related to a retrusive maxilla or protrusive mandible.