The purpose of this study was to evaluate whether change in cuspal inclination influences the fracture load values of composite resin computer-aided design/computer-aided manufacturing (CAD/CAM) crowns. Abutment teeth and CAD/CAM crowns were prepared as they would be for treating a mandibular first premolar with two cusps. The CAD/CAM crowns were designed so that 1) the principal stress lines would be radially distributed from the two points of contact with the indenter to the occlusal area of the abutment (Type I), or 2) the principal stress lines would pass outside the occlusal area of the abutment (Types II and III). The CAD/CAM crowns were mounted on the abutments using one of two types of resin or polycarboxylate cement. Fracture load values were measured using a universal tester. The Type I CAD/CAM crowns exhibited the highest mean fracture load value, followed by the Type II crowns and then the Type III crowns, with significant differences seen between all types (p<0.05). The luting agent used (resin or polycarboxylate cement) showed no effect on the fracture load value. With the Type II and Type III crowns, significant differences in the fracture load value were observed between the Super-Bond and Hy-Bond polycarboxylate cement groups (p<0.05).

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Dentistry plays an important role in the identification of victims in large-scale disasters. The current poor status of and problems with victim identification work were highlighted in the aftermath of the Great East Japan Earthquake of March 11, 2011, in which some 10,000 people lost their lives. The techniques of dental identification therefore need to be improved if they are to cope with the problems associated with identification that will accompany the predicted Tokai earthquake and other unexpected large-scale disasters in the future. The purpose of this study was to determine the effectiveness of applying a digital impression-taking device employed in regular dental care to dental personal identification. The Trophy 3DI pro (Yoshida Dental) was applied to a total of 150 dental models. The diagnosis was accurate in 2,096 teeth from a sample of 2,100 comprising 1,240 non-treated teeth, 670 treated teeth, and 190 missing teeth, yielding a 99.8% level of statistical precision. These results suggest that the level of accuracy offered by this impression-taking device indicates that it would be a useful tool in establishing personal identification in disaster victims.

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Serum serves as a source of rich nutrients during in vitro cell culture, facilitating cell adhesion, growth, and differentiation. When culturing stem cells for transplantation, however, it must be remembered that such culture medium may contain substances potentially harmful to the proposed recipient and may even induce cellular damage. The purpose of this study was to determine whether KnockOut Serum Replacement (KSR), a chemically defined medium supplement, enhanced in vitro differentiation of induced pluripotent stem cells into odontoblasts. Cranial neural crest cells, precursors of odontoblasts, were generated from mouse-induced pluripotent stem cells. They were then cultured in serum-free Dulbecco’s modified Eagle’s/F12 medium containing fibroblast growth factor 8 with or without KSR. The cells cultured with KSR showed strong proliferation, acquired a spindle-like morphology, and connected with the surrounding cells. KnockOut Serum Replacement also boosted expression of odontoblast markers as measured by qRT-PCR, and increased dentin sialoprotein as assessed by immunostaining. These results confirmed that mouse-induced pluripotent stem cells differentiated into odontoblasts under serum-free conditions, and that KSR enhanced the efficiency of this process.

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This report describes a case of generalized chronic periodontitis requiring periodontal treatment including surgery. The patient was a 64-year-old man who visited the Tokyo Dental College Suidobashi Hospital with the chief complaint of pain in tooth #27. An initial examination revealed a probing depth (PD) of ≥4 mm at 38.2% of sites and bleeding on probing at 26.5% of sites. Radiographic examination revealed vertical bone resorption in # 27, 34, and 47, and horizontal resorption in other areas. Based on a clinical diagnosis of severe chronic periodontitis, initial periodontal therapy consisting of plaque control, scaling and root planing was performed. Both #27 and #47 were extracted due to bone resorption extending as far as the root apex. After initial periodontal therapy, sites with a PD of ≥4 mm were observed at 16.7% of sites. Furcation involvement was observed in #16, 17, 36, and 37. The need and options for periodontal surgery based on these findings were explained to the patient. Open flap debridement was implemented for #16, 17, 31, 34, 36, and 37 to reduce periodontal pockets. After reevaluation, the patient was placed on supportive periodontal therapy. The results of the periodontal examination at first visit revealed a periodontal pocket depth of 6 mm and 7 mm in #16 and 17, respectively, and class II furcation involvement in both. Periodontal therapy with open flap debridement resulted in an improvement in horizontal bone resorption where there was class II furcation involvement. This improvement has been adequately maintained over a 4-year period.

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This report describes a case of generalized chronic periodontitis requiring periodontal therapy including periodontal regeneration. The patient was a 59-year-old man who visited the Tokyo Dental College Suidobashi Hospital with the chief complaint of mobility in tooth #47. Periodontal examination at the first visit revealed that 32.1% of sites had a probing depth of ≥4 mm and 32.7% of sites bleeding on probing. Radiographic examination revealed vertical bone resorption in #26 and horizontal resorption in #12, 13, 42, and 43. Based on a clinical diagnosis of severe chronic periodontitis, initial periodontal therapy consisting of plaque control, scaling and root planing, occlusal adjustment, caries treatment, and placement of an occlusal splint was performed. Tooth #47 was extracted due to bone resorption extending as far as the root apex. After reevaluation, surgical periodontal treatment was performed at the selected site. Periodontal regenerative therapy using recombinant human fibroblast growth factor (rhFGF)-2 and papilla preservation technique was performed for #26. To reduce periodontal pockets, open flap debridement was implemented for #12, 13, 42, and 43. After reevaluation, the patient was placed on supportive periodontal therapy (SPT). Periodontal regenerative therapy with rhFGF-2 and modified papilla preservation technique yielded an improvement in angular bone resorption which has been properly maintained for two years. Periodontal therapy with open flap debridement resulted in an improvement in horizontal bone resorption. Continued SPT is needed to maintain a stable periodontal condition.

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