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The functional role of CD14 and Toll-like receptor (TLR) in the Porphyromonas gingivalis lipopolysaccharide (Pg-LPS)-induced activation of B cells was assessed, using CD14-, TLR2- and TLR4-overexpressed murine B cells (CH12.LX). After stimulation with Pg-LPS, CD14- and TLR4-transfected, but not TLR2-transfected, CH12.LX showed higher induction of nuclear factor (NF)-κB activation. Although Pg-LPS induced control CH12.LX to proliferate accompanying by up-regulations of TGF-β and IL-6 mRNA, CD14-transfected cells showed the up-regulation of TGF-β mRNA, but not IL-6 mRNA nor proliferative responses to Pg-LPS. Thus, Pg-LPS could induce B cell activation both in CD14-dependent and independent pathways: In a CD14-dependent pathway, TGF-β production could be induced through TLR4 and NF-κB activation. In contrast, Pg-LPS induced proliferation and IL-6 production in the CD14-independent pathway.

Although T-cells are thought to play central roles in Ni-allergy, this idea is based largely on in vitro studies, because in vivo studies have been limited by the paucity of adequate murine models of Ni-allergy (and indeed it has been said that it is difficult to induce Ni-allergy in mice). However, we recently found that a lipopolysaccharide (LPS) of Escherichia coli acted as a potent adjuvant, sensitizing mice to Ni. LPS also sensitized mice to other metals (Cr, Co, Pd, and Ag). Here, we report that in addition to LPS, a variety of microbial or inflammatory substances sensitize mice to Ni. Our findings suggest that a microbial or an inflammatory milieu is an important factor leading to metal allergies.

We carried out residents-attractive dental health examinations by increasing the learning contents with systemic health examination of a rural town in Japan. Town staffs or some residents who had finished training programs participated in the dental examinations as staffs. Oral malodor was measured to motivate oral hygiene of examinees. We prepared questionnaires and asked the impression of examinees about “the dental examination with learning” 7 months after the examination. Questionnaires showed that 85% of dental examinees recognized it as satisfactory. This fact indicates the possibility that the new dental examination can be a model for oral health promotion in the community.

To diagnose the activities and progressions of dental caries lesions, we developed nondestructive measuring device to detect and quantify the mineral loss in the early stage of caries. This novel device with ultrasonic technology measures acoustic frequency characteristics of the tooth surface. Extracted human tooth were embedded in polymethylmethacrylate and polished. The results of the repeated measurements indicated the sufficient reproducibility of acoustic measurements in same samples. Since this acoustic measurement was influenced by the moist condition of tooth surfaces, tooth surfaces should be air-dried and quickly measured for the reproducibility in clinics. We developed the nondestructive ultrasonic measuring device to detect the mineral loss from tooth surfaces and diagnose the initial change of progression of dental caries lesions in enamel and dentine.

To reduce the errors of the periodontal probing measurements, we developed a novel constant load periodontal probe, Tohoku University-type constant load periodontal probe (TUCL probe), which has a similar shape with the one used commonly. The tip of the TUCL probe buckles at the hinge of the handle by the excess load on the tip. The probing forces performed by six new resident dentists were recorded by using the model tooth with pressure sensor mounted on the dummy jaw. The maximal force probed upper right first incisor showed 28 to 109 g (average 56 g) when using normal CPI probes. When they used TUCL probes, however, their maximal probing force showed 16 to 33 g (average 20 g). This indicated TUCL probe could exclude the exceed load of probing, which depends on the examiner’s skill. The novel TUCL probe with constant probing load will standardize the periodontal probing examination.

It takes time to learn accurate probing skills, because it is difficult to minimize inherent probing measurement error. Thus, we invented the Tohoku University-type constant load periodontal probe (TUCL probe) to standardize the probing measurements. The TUCL probe gives constant probing force by itself. In this study, we reported the application of the TUCL probe in the training of the probing operation. The probing forces of 60 new dental hygienist students were recorded before and after the practice by using conventional probe and weighing scale, or TUCL probe. For learning the force for probing, 36% of students reported that the TUCL probe was an easier learning tool, compared to the weighing scale. In conclusion, the TUCL probe is a significantly useful instrument, not only for standardizing probing measurement, but also for probing operation training.

Halitosis is a common oral concern and patients often seek help from dentists. The purpose of this study is to evaluate psychological characteristics of halitosis patients and their changes with treatment. The subjects consisted of 150 halitosis patients and 64 non-halitosis patients. They were requested to complete Egogram and the halitosis scale questionnaires, before and after treatment. The results indicated that halitosis patients improved in the objective recognition of their malodor level, their obsession with halitosis, and interpersonal communication after treatment. Therefore, the ideal dentist attitude for halitosis treatment is to help patients overcome their obsession by examining their breath level repeatedly and encourage them to develop social skills. However, these subjects had a tendency for social phobia, and its removal was not easy. Therefore, it would be essential that dentists continue to accept their complaints and relapse of their obsession with bad breath sincerely.

This study is an examination of the released ions from dental cast experimental Ti-Ag alloys by an immersion test. Ti-Ag alloys (5–25mass%Ag) and pure titanium (control) were cast into magnesia molds; the hardened surface layer was then removed. After each specimen was immersed in aerated 0.9% NaCl or 1% lactic acid solution at 37°C for 7 days, released ions were analyzed using inductively coupled plasma. Cast Ti-Ag alloys with Ag ≤ 20% formed a single α structure. Ti and Ag ions were not detected from the alloys and pure titanium in the NaCl solution. The microstructures of cast Ti-Ag alloys with 22.5% Ag and 25% Ag consisted of α + intermetallic compounds (Ti_2Ag or Ti_2Ag + TiAg). A small amount of Ti and Ag ions was detected from some of the 22.5% Ag and 25% Ag specimens in the NaCl solution. The preferential dissolution of parts of the intermetallic compounds was observed in the specimens after the test. In the lactic acid solution, a significantly smaller amount of Ti ions was released from all the Ti-Ag alloys than from pure titanium. Ag ions were not detected. The intermetallic compounds remained on the specimen surfaces after the test in the lactic acid solution.

TiO_2 (titania) films on titanium substrates were fabricated by electron cyclotron resonance (ECR) plasma oxidation. A calcification experiment of the Ti substrates treated with the ECR plasma was carried out by immersing in a supersaturated solution with respect to hydroxyapatite (HA) and octacalcium phosphate (OCP), but slightly saturated with respect to dicalcium phosphate, dihydrate (DCPD). After the immersion, OCP precipitated predominantly on TiO2 film, whereas formation of HA, the most stable phase under physiological condition, was inhibited. The calcification ability was affected by the substrate temperature during the ECR plasma oxidation. The surface roughness increased with increasing the oxidation temperature. These results indicate that the surface oxidation by ECR plasma modulates the surface characteristics to enhance OCP precipitation.

Extracellular matrix (ECM) of bone tissue consists of a highly organised nanocomposite made of fibrillar collagen type I and calcium phosphate mineral phase hydroxyapatite. We have developed a process to synthesise a material, mimicking bone ECM, and produced several biomaterials out of this mineralised collagen, suitable for use in oral medicine and maxillofacial as well as in general surgery. Synthesis of the nanocomposite, development of the different types of scaffolds, some of their properties, and possible applications are discussed.