Purpose: This study investigated the effects of the main ions thought to be released from bioactive dental materials on the proliferation and differentiation of MC3T3-E1 murine osteoblasts.

Methods: Cell proliferation was assessed in a control group (minimum essential medium α) and in several ion groups (control group medium + aluminum, boron, sodium fluoride, or strontium ions) to determine which ions affect the osteogenic response to MC3T3-E1. Three groups of MC3T3-E1 cells, namely, a control group, a lipopolysaccharide (LPS) group (control + 5 μg/mL LPS), and a strontium group (control + 1 mM strontium ions) were cultured for 7 days.

Results: Significant differences in cell proliferation were observed in the strontium group (P < 0.05) but not in the aluminum, boron, or sodium fluoride ion groups. Cell proliferation was enhanced in the strontium group compared with the control group (P < 0.05). Cytotoxicity was not observed in any of the groups (P < 0.05). The strontium group had the highest alkaline phosphatase (ALP) activity (P < 0.05) and the greatest degree of ALP staining, indicating that strontium affected cell differentiation. Collagen production was the highest in the control group and the lowest in the LPS group (P < 0.05).

Conclusion: Media containing 1 mM strontium ions promoted osteoblastic differentiation in MC3T3-E1 cells without causing cytotoxicity. Further research is needed to determine the influence of culture time and the minimum concentration for each ion.

Purpose: Optical coherence tomography (OCT) is an imaging device that can create cross-sectional images of tooth structure. This study evaluated the diagnostic performance of dental OCT system for occlusal caries in a real clinical situation.

Methods: Twenty-four occlusal locations on 20 teeth were selected from 12 patients (mean age: 39.6 years). Swept-source OCT (SS-OCT) images were taken from the occlusal surfaces to diagnose occlusal enamel caries using the international caries detection and assessment system (ICDAS) grading. Indices of sensitivity and specificity for the detection of superficial enamel demineralization (code 1), distinct enamel demineralization (code 2), and enamel caries (code 3) were calculated from the results of visual inspection and SS-OCT obtained by three dentists with less than 2 years clinical experience.

Results: The sensitivity of visual inspection and SS-OCT for enamel demineralization (code 1) were 0.22 and 0.55; for enamel demineralization (code 2) were 0.50 and 0.61; and for enamel caries (code 3) were 0.22 and 0.44, respectively. The specificity of visual inspection and SS-OCT were 0.52 and 0.78, respectively.

Conclusion: SS-OCT can provide excellent diagnostic performance for occlusal enamel caries in a real clinical situation.

This report describes the case of a 52-year-old woman with oral lichen planus due to a dental metal allergy, who was treated successfully by removing metal restorations and replacing them with a zirconia centered non-metal based fixed partial denture (FPD). Following basic periodontal treatment, all intraoral metal restorations were removed, and provisional restorations were placed. After approximately 3 months of follow-up, allergic symptoms had resolved, and the patient received the definitive prosthetic treatment. A monolithic zirconia FPD was selected for the molars, and a porcelain layered zirconia FPD was selected for the anterior dentition. The patient wished to improve the form of the contralateral maxillary anterior tooth, for which a laminate veneer restoration was planned. For the placement of the zirconia FPDs, alumina blasting was applied to the inner surface of the FPDs, and the placement operation was performed according to the instruction manual for the adhesive resin luting agent used. After completion of prosthetic treatment, maintenance was performed every 4 months, and 4 years and 4 months have passed. The periodontium was in good condition, and there was no evidence of secondary caries, debonding, fracture of the FPDs, or abnormal jaw function. Allergic symptoms are in remission, and the FPDs are in good condition based on patient satisfaction.