We attempted to determine the efficacy of fluoride dentifrice on remineralization of white spot lesions using quantitative light-induced fluorescence (QLF). The study was approved by the Ethics Committee at Osaka Dental University Hospital prior to recruiting patients. All subjects gave their informed consent and 129 patients completed the clinical study. They were allocated randomly to the fluoride group and the placebo group, with 65 subjects using fluoride dentifrice containing 950ppm fluoride (NaF), and 64 using placebo dentifrice without fluoride. The patients were required to brush their teeth twice a day using the assigned dentifrices for one year. The remineralization effects of the fluoride and placebo dentifrices were evaluated by three QLF parameters: ΔQ (%・mm²), mineral loss; S (mm²), lesion area; and ΔMax (%), maximum lesion depth at three, six and twelve months recalls after the baseline examination. We concluded that the fluoride dentifrice improved remineralization of the clinical white spot lesions.

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I fabricated composite resin cores using fiber posts (Snowpost; Carbotech Co., Lewis Center, OH, USA) and prefabricated metal posts (AD Post; Kurary Co., Tokyo, Japan), and compared the fracture resistance and the type of fracture of posts and cores cemented in the abutment tooth. Post canals were created in maxillary lateral incisor roots in preparation for receiving a crown. A fiber or prefabricated metal post was bonded to the root canal with resin cement (Panavia Fluoro Cement; Kurary), and composite resin cores were fabricated by the direct technique. In addition, post-cores fabricated by the indirect method using a fiber post and hybrid-type composite resin were also bonded to root canals using adhesive resin cement. All samples were loaded at an inclination of 45 degrees with the vertical axis to assess fracture resistance.
The combination of a prefabricated metal post with composite resin exhibited the greatest fracture resistance (88.1kgf), the combination of a fiber post and composite resin core showed the lowest resistance (62.7kgf), and the post and core fabricated using a fiber post and hybrid-type composite resin with the indirect method had a fracture resistance of 68.8kgf. The t-test identified a significant difference in fracture resistance between the fiber and metal posts. Moreover, in the fiber post group, the post core was displaced without fracturing the root, while the metal post caused root fracture on the side opposite that of loading.

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Using tissue engineering techniques, we developed osteogenetic graft materials composed of autogenous mesenchymal stem cells (MSCs) harvested from bone marrow and platelet-rich plasma (PRP) prepared from the patient's blood. In order to improve predict-ability of implant and periodontal regenerative therapies, we devised a fabric structural composite scaffold that maintains space for the transplanted cells to regenerate tissue. For the purpose of conducting in vitro verification of the osteogenetic potential of the osteoblast-like cells injected into the woven fabric composite scaffold, these cells were incubated for an extended period of time on the scaffold and evaluations were conducted on the scaffold interface. The in vitro evaluations verified the capacity of human MSCs adhering to the scaffold to differentiate into osteoblast-like cells under the defined differentiation inducing conditions, leading to significant mineralization.
These results verify that the woven fabric composite scaffold, infused with gelled material formed with cultured osteogenetic cells and PRP, can be used as an osteogenetic graft material in bone regenerative therapy around implants. These materials now await further evaluation by animal trials.

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Placement of dental implants requires precise planning that accounts for anatomic limitations and restorative goals. The purpose of this study was to evaluate in vitro the accuracy of implant placement with the implant guide system developed by Koyanagi.
Ten dentists, five of whom were experienced and five of whom were inexperienced in implant surgery, placed the implants on identical models of the mandible using surgical templates fabricated based on data acquired from CT images. The preoperative CT images were compared with postoperative images to assess the differences between the planned and installed implants with respect to inclination, positions of the base and tip, and insertion depth of the implant.
The average inclination discrepancy between the planned and installed implants was 0.73° in the mesiodistal direction and 1.02° in the buccolingual direction. The average deviation of the base position was 0.36 mm in the mesiodistal direction, and 0.06 mm in the buccolingual direction. The average deviation of tip position was 0.23 mm in the mesiodistal direction, 0.06 mm in the buccolingual direction. The average deviation of insertion depth was 0.43 mm. The variances in mesiodistal direction of inclination, buccolingual position of the tip, and depth of insertion for the inexperienced operators were significantly greater than those for the experienced operators.
This in vitro study of application of the implant guide system indicated improved precision of surgical placement of the implants regardless of the experience of the operator.

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Using cats anesthetized with pentobarbital, the activity of high-threshold nociceptive neurons that responded to injection of 5% NaCl solution (hypertonic solution) in the splenius muscle (i.e., chemical stimulation using a muscle pain-producing substance) was investigated in the caudal medulla oblongata and thalamus to thoroughly evaluate the functional properties of muscle pain neurons, to clarify modification of muscle pain neurons in the central nervous system, and to ascertain the physiological significance of these findings.
The extracellular activity of single neurons was obtained from the reticular formation in the caudal medulla oblongata (BRF), as well as the nucleus parafascicularis (Pf) and the nucleus centralis lateralis (CL) belonging to the intralaminar nuclei (IL) in the thalamus.
Neurons detected from the BRF display peripheral receptive fields spreading to the maxillofacial or trunk areas and respond to nociceptive mechanical stimuli applied to deep subcutaneous tissue. Neurons detected from the Pf and CL showed broad peripheral receptive fields like neurons in the BRF and responded to nociceptive mechanical stimulation to the deep tissue of the trunk.
The above results clarify that afferent fibers relaying pain information of the splenius muscle project to the BRF and then ascend to the IL. In addition, the results for convergence of neurons in the relay nucleus are useful in explaining referred pain involving the splenius muscle.

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How the orexins, which are neuropeptides that play an important role in maintaining wakefulness, modulate the hypnotic effect of general anesthetics is not well understood. We administered orexin A to rats under sevoflurane anesthesia to investigate its effect on the electroencephalogram (EEG), cerebral blood flow (CBF), and mean arterial pressure (MAP). After confirmation of the presence of burst suppression patterns by EEG, rats anesthetized with 3% sevoflurane received intraventricular administration of orexin A at 1nmol/5μL. We observed changes in EEG, CBF, and MAP before and after the admini-stration. Burst suppression patterns on the EEG disappeared in some rats and the frequency of bursts was increased in others. CBF was increased after administration of orexin A. It is believed that orexin nerves activate the brainstem, which regulates sleep and wakefulness. The induction of waking EEG patterns by intraventricular administration of orexin A indicates that it modulates the anesthetic effect of sevoflurane.

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The compressive impression method, which takes into consideration occlusal pressure during function, is generally used when taking impressions for complete dentures. However, the deformation of oral mucosa caused by pressure has not been clarified, and use of this method is often based on the dentist's experience and subjective judgment. We attempted to clarify the effect of the oral mucosa thickness on changes in load under occlusal force. We measured the thickness of oral mucosa under occlusal force using a measurement system based on the ultrasonic pulse-echo method. Analysis of variance demonstrated that there were significant differences in the compression rate between the measurement regions (p<0.001).

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