In recent years, with the increasing social awareness of safety in medical practice, improving clinical skills has become very important, especially for recently graduated dentists. Traditionally, mannequins have been used for clinical skill training, but a mannequin is quite different from a real patient because they have no autonomous movement or conversational ability. This indicates that pre‐clinical simulation education is inadequate. We have, therefore, developed a robot patient that can reproduce an authentic clinical situation for dental clinical training. The robot patient, designed as a full‐body model with a height of 157 cm, has eight degrees of freedom in the head and the ability to perform various autonomous movements. Moreover, saliva secretion and conversation with the trainee can be reproduced. We have introduced the robot patient into an objective structured clinical examination targeted at fifth‐grade students in our dental school to evaluate their skills in cavity preparation, whilst considering the safety of the treatment. As a result, many of the students were able to deal appropriately with a patient’s unexpected movement. Moreover, results of a questionnaire survey showed that almost all the students recognised the educational value of the robot patient especially for ‘risk management’, and they preferred the robot patient to traditional mannequins. Practical application of the robot patient in dental clinical education was evaluated through the experiences of the fifth‐grade students, which showed the effectiveness of the robot patient in the dental field.

Physical changes in the surface characteristics of dentin during bonding procedures were evaluated by measuring the contact angles of three standard liquids, to determine the surface free energy, and that of a commercially available dual cured dentin bonding agent dropped on the primed dentin surface. The commercial dentin bonding agent did not form a hemispherical shape on the ground dentin surface, probably because it penetrated into the smear layer due to the microcapillary effect. Not could the contact angle be measured on the dentin surfaces treated with any of four experimental primers, because the bonding agent rapidly spread over the primed dentin surface. It was concluded that the priming of the dentin surface after removing the smear layer served to increase the surface free energy and to improve the wettability of the bonding agent on the dentin.

The bonding efficacy of sclerotic dentin was determined by measuring the polymerization contraction gap width of a commercial light-activated resin composite in a cervical defect and by measuring the micro-Vicker's hardness at the dentin adhesive surface; morphological characteristics were observed using a scanning electron microscope in extracted human incisors and premolars. Contraction gap formation was completely prevented when the cavity wall was primed with 35vol% glyceryl mono-methacrylate solution after 0.5mol/L EDTA conditioning. The contraction gap width was significantly decreased when the resin composite was filled into the sclerotic dentin cavity even when priming was omitted. These results suggest that the sclerotic dentin, which is frequently observed in cervical defects, should be preserved as a substrate because it exhibits an effect of dentin priming and is suitable for bonding.

No abstract

The effect of adding micro filler to 4-META MMA/TBB dentin bonding agent was examined by measuring the wall-to-wall polymerization contraction gap of a commercial light-cured resin composite in a cylindrical dentin cavity and the tensile bond strength of the flat dentin surface. Gap formation was not completely prevented by using a filled dentin bonding agent although the tensile bond strength was significantly greater than that obtained using the unfilled dentin bonding agent. These results indicate that the addition of micro filler to the dentin bonding agent does not produce complete adaptation of the resin composite to the dentin cavity wall.