Abstract : A survey concerning cracks and fractures of vital teeth was carried out at Conservative Dentistry and Comprehensive Dentistry, Kyushu Dental University Hospital. Thirty-nine vital and non-vital teeth without treatment were diagnosed as having tooth crack or fracture during three years (2009～2011). The largest age group consisted of those in their forties (28.2%) ; there was no significant difference between the sexes. More than half of the diseased teeth (56.4%) had not been restored. Tooth cracks and fractures were often found in the maxillary and mandibular first molars, and mesio-distal fracture lines at the occlusal surface were found in 66.7% of subjects. The ratio of conservative treatment by adhesive resin with microscope to all subjects was 87.2%. These results suggest that cracks and fractures of vital and non-vital teeth without treatment may arise from some characteristics such as type of tooth and patient factors.

Abstract : The purpose of this study was to evaluate the effect of heat shock protein 70 (HSP70) and matrix Gla protein (MGP) on calcification by BMP-2 in human dental pulp cells (HDPC). The HDPC were stimulated with 10 ng/ml bone morphogenetic protein-2 (BMP-2), 100 ng/ml HSP70 and 25 ng/ml MGP. The group without treatment as a control and the experimental groups were decided as follows : ① BMP-2 (B group), ② BMP-2+MGP (B・M group), and ③ BMP-2+MGP+HSP70 (B・M・H group). To evaluate the effect of calcification on HDPC, we stained HDPC after 7 and 14 days with Alizarin red S staining. We quantitatively examined the calcified nodule by HDPC. In addition, we examined Smad1/5/8 phosphorylation by using Western blotting. The intensity of Alizarin red S staining of HDPC groups was in the order of B group ≑ B・M・H group > control group ≑ B・M group. Smad1/5/8 phosphorylation was enhanced in the B group and B・M・H group, but was not enhanced in the B・M group. BMP-2 binds with receptor by HSP70 inhibition MGP effect, and enhances Smad1/5/8 phosphorylation. HSP70 inhibits MGP and promotes HDPC calcification by BMP-2.

Abstract : The purpose of this study was to investigate the effects of Emdogain^® gel (EMD) on cementogenesis within the vicinity of the destroyed apical foramen. Experimental rat periapical lesions were induced by opening the pulp chambers of the mandibular first molars and penetrating and filing the apical foramen through the distal root canal with #25 K-files to avoid breaking the root apex. Exposed teeth were kept open to the oral environment for 7 days and for 28 days. Then, we irrigated the distal root canals and divided them into two groups. One was the EMD-treated group, and the other was the Propylene glycol alginate (PGA)-treated group as the positive control, which was a carrier of EMD. The rats were sacrificed 28 days after treatment and prepared for histochemical examination. In the EMD-treated rats, there was significant cementogenesis within the vicinity of the destroyed apical foramen in each experimental group. These results suggest that EMD may be beneficial for creating a favorable environment promoting wound healing of destroyed periapical tissues.