An experimental study on mineral triozide aggregate and calcium hydroxide-based paste applied to direct pulp capping in rat / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the volume change of rat root following direct pulp capping with mineral triozide aggregate(MTA) and calcium hydroxide-based paste (Vitapex) .</p><p><b>METHODS</b>Sixty-four female, 1-month-old Wistar rats were randomly divided into 4 groups, MTA group, Vitapex group, model group and control group, 16 rats in each group. The right maxillary first molar was taken as experimental tooth and control tooth. The exposed pulp was capped separately with MTA and calcium hydroxide after the pulp had been exposed mechanically, while nothing done to the control group. Using micro-CT and three-dimensional reconstruction techniques, the volume change of rat root was evaluated at 1, 2, 4 weeks and 6 weeks after direct pulp capping. The data were analyzed by an way ANOVA analysis followed by a LSD-t test.</p><p><b>RESULTS</b>The root volume in the MTA group[(1.08 ± 0.07), (1.32 ± 0.18) mm(3)] was significantly smaller than that in the Vitapex group[(1.28 ± 0.16), (1.59 ± 0.18) mm(3)] at 2 and 4 weeks after operation (P < 0.05) . At the sixth week , there was no significant difference between the MTA group [(1.36 ± 0.03) mm(3)] and the Vitapex group[(1.61 ± 0.31) mm(3)] (P > 0.05) . The root volume in the MTA group and Vitapex group was significantly larger than that in the model group [(0.87 ± 0.09), (1.01 ± 0.17) , (1.02 ± 0.25) mm(3)] from the second to sixth week after operation (P < 0.05) .</p><p><b>CONCLUSIONS</b>MTA and Vitapex can effectively promote root formation and growth and can be used as biological pulp-capping material.</p>

Influences of thermal and gustatory characteristics on sensory and motor aspects of swallowing.

Two sets of experiments were conducted to examine the effects of two sensory modalities, temperature and taste, of foods on perceptual and motor aspects of swallowing in 20 young, healthy subjects (10 subjects for each experiment). A tasteless and odorless thickening agent was the basic testing material. The first experiment compared the swallowing of foods at four temperatures ranging from 5 degrees C to 50 degrees C. Food at 50 degrees C was more acceptable for swallowing than at 5 degrees C, 20 degrees C, or 35 degrees C. The suprahyoid muscles were less active during swallowing food at 50 degrees C compared with swallowing food at the other three temperatures. The second experiment compared foods with the five basic taste qualities (sweetness, saltiness, sourness, bitterness, and umami) with a tasteless food (dissolved in distilled water) to examine the influence of gustatory sensation. The sweet and tasteless foods were somewhat more acceptable for swallowing than the sour and bitter foods. However, none of the foods differentially altered the motor parameters of swallowing. Interactive influences of temperature and gustatory sensations of foods on swallowing are discussed.