The purpose of this study was to investigate the incidence of coronal and root caries in participants aged 20–59 years in Japan. The participants comprised 118 men and 23 women undergoing a re-examination 5 years after an initial examination. Lesions were classified as gingival recession, decayed root caries, or filled surfaces. The rates of incidence of coronal caries over the 5 years were 87% in women aged 20–29 years, 77% in men aged 20–29 years, 62% in men aged 30–39 years, 64% in men aged 40–49 years, and 60% in men aged 50–59 years. The rates for those observed to be at risk for the incidence of root caries were 25% for women aged 20–29 years, 16% for men aged 20–29 years, 11% for men aged 30–39 years, 43% for men aged 40–49 years, and 35% for men aged 50–59 years. The distribution for the number of new coronal and root caries lesions was 68.8% and 24.1%, respectively. Univariate logistic regression analyses for new coronal caries revealed that the risk factors were age group at baseline (OR=0.702, p=0.0440), number of coronal decayed and filled surfaces at baseline (OR=2.893, p=0.0107), and number of sound teeth at baseline (OR=3.381, p=0.0013). Moreover, univariate logistic regression analyses for new root caries revealed that the risk factors were age group at baseline (OR=1.787, p=0.0039), presence or absence of gingival recession at baseline (OR=3.288, p=0.0062), and presence or absence of root decayed and filled surfaces at baseline (OR=11.00, p<0.0001). It was concluded from these results that the target of caries prevention in adults should not only be focused on root surfaces, especially in those aged 40 years or over, but also on the coronal surfaces of the dentition in those in their twenties.

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Videofluorography is frequently used to evaluate swallowing and is considered the “gold standard” among imaging modalities. This modality, however, has several disadvantages, including radiation exposure and limitations in the detection of soft tissues. Conversely, magnetic resonance imaging (MRI) offers excellent contrast resolution in soft tissue without radiation exposure. A major drawback of MRI in evaluating swallowing, however, is that temporal resolution is poor. The aim of this study was to investigate a new cine-MRI modality. Imaging parameters were optimized and the efficacy of this new technique is discussed. Three techniques for speeding up MRI were combined: true fast imaging with steady state precession, generalized auto-calibrating partially parallel acquisition, and key-hole imaging. The effects of the receiver coils used, receiving bandwidth, slice thickness, and flip angle on each image were determined. The optimal imaging parameters obtained comprised a reduction factor of 2, receiving bandwidth of 1,000 Hz/pixel (repetition time of 151.7 milliseconds and echo time of 1.4 milliseconds), flip angle of 50°, and slice thickness of 6 mm. Neck and spine coils were used. Under these conditions, the new cine-MR imaging technique investigated showed a temporal resolution of 0.1 sec/slice (10 frames/sec). Even with optimized parameter settings, this technique did not allow a true temporal resolution of 30 frames/sec by a large margin. Motion artifacts persisted. Further study is needed on how to speed up this technique.

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β-defensins are small, cationic peptides with broad-spectrum antimicrobial activity that are produced by mucosal epithelia. However, little is known about the expression of β-defensins in the major salivary glands. The purpose of this study was to characterize expression of rat β-defensin-1 (RBD-1) and -2 (RBD-2) mRNA within the major salivary glands together with the effect of injection of intraductal lipopolysaccharide (LPS) on that expression. β-defensin mRNA expression was quantitated by RT-PCR in salivary gland tissues and salivary acinar and striated duct cells collected by laser captured microdissection. RBD-1 and -2 were expressed in the parotid gland, the submandibular gland, and the sublingual gland. β-defensins were expressed in both the acinar and striated duct cells of the major salivary glands. Intraductal injection of LPS increased expression of RBD-1 and -2 mRNA, which peaked at 12 hrs. These results suggest that salivary cells (acinar and striated duct cells) have the potential to produce β-defensins.

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Yttrium tetragonal zirconia polycrystal frameworks were prepared for all-ceramic fixed partial dentures (FPDs) for the mandibular incisor region. The effects of the cross-sectional area and morphology of the connector on its strength were evaluated by fracture tests. Nine types of zirconia framework for a 3-unit FPD for a defect of 1 mandibular central incisor were prepared, each differing in cross-sectional area and morphology. Fracture tests were performed by loading until fracture using a universal testing machine. Fracture load was determined and fracture site examined. Significant differences were observed in fracture load according to the morphology and cross-sectional area of the connector (p<0.05, p<0.01, p<0.001). Fracture load differed significantly among all groups according to cross-sectional area, and was also greater when the shape of the connector formed an isosceles triangle widest at the base and the connector had the same height and width. These values still far exceeded 311 N, however, which is the average occlusal force in the incisor region. The results of this study suggest that connector design affects fracture load.

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Use of intravenous sedation is increasing in the management of dental patients in consideration of accompanying diseases and patient demand for comfort and safety. We surveyed choice of sedative agent and dosage on the basis of accompanying diseases or conditions in patients receiving treatment at the Department of Dental Anesthesiology, Tokyo Dental College Chiba Hospital between 2010 and 2011. A total of 5,256 patients were reviewed and divided into the following categories: 1) medically compromised patients (MC); 2) minor oral surgery (OS); 3) cerebral palsy (CP); 4) mental retardation (MR); 5) mental disorder (MD); and 6) dental phobia with/without gag reflex. The investigated variables were sex, age, weight, duration of sedation, and dosage of agent. Dosage of midazolam (M), M plus propofol (MP), and P alone was investigated. A total of 2,336 patients were managed by intravenous sedation during the study period. The combination of MP was used in approximately 63–79% of patients in all categories, except MC. Midazolam was used in approximately 47% in the MC group. Propofol was used in approximately 32% of patients in the MR group. Other agents (minor tranquilizers, analgesics, and so on) were used in approximately 12% in the OS group. The dose of M was approximately 0.05–0.06 mg/kg. When MP was administered, the dose of M showed no difference among groups. The dose of P, however, tended to be lower in the MC and CP groups than in the other groups. These results suggest that MP is chosen for intravenous sedation in most types of dental treatment.

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Adrenaline (Adr) is known to directly or indirectly modulate bone cell activity under physiological and pathological conditions. Osteoblasts play a major role in bone formation, employing intracellular Ca²⁺ as a second messenger to modulate hormonal responses and as a cofactor for mineralization. Voltage-dependent Ca²⁺ channels (VDCCs) mediate the influx of Ca²⁺ in response to membrane depolarization. The purpose of this study was to investigate the effects of Adr on VDCC currents in osteoblasts using a patch-clamp recording method. Application of 1 mM Adr facilitated VDCC currents in a concentrationdependent manner. Pre-treatment with b receptor antagonist propranolol blocked Adrinduced facilitation of VDCC currents carried by Ba²⁺ (I_Ba). These results indicate that Adr-induced facilitation of I_Ba was mediated by b receptors in MC3T3-E1 osteoblast-like cells. To our knowledge, the data presented here demonstrate for the first time that Adr facilitates VDCCs in MC3T3-E1 osteoblast-like cells.

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The Acknowledgements section should be changed as follows:

The authors thank Associate Professor Naoki Sugihara from Department of Epidemiology and Public Health for his advice on the statistical analysis.
This study was conducted with the approval of the Ethics Committee of Tokyo Dental College (Approval No.385).

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