Yutaka Komasa

A torque removal study on the primary stability of orthodontic titanium screw mini-implants in the cortical bone of dog femurs.

The aim of this study was to biomechanically evaluate the primary stability of pure titanium orthodontic mini-implants, inserted into pre-drilled cavities of differing diameters. Mini-implants (1.2 mm diameter) were placed into 1.0 mm and 1.2 mm diameter cavities prepared in the mid-region of the bilateral hind leg femurs of anesthetized beagles. Removal torque strengths were measured immediately, 1, 3, 6, 9 and 12 weeks post-insertion of the implant. For mini-implants placed into 1-mm cavities, removal torque values decrease over the first 6 weeks (p<0.01), after which values remained static. Average values obtained immediately, 1, 3 and 6 weeks post-insertion were 10.98, 8.83, 7.20 and 5.12 Ncm, respectively . Immediately post-insertion, removal torque values of mini-implants placed in a 1.2-mm cavity, were 11-fold lower than those placed in 1.0-mm cavities, which then demonstrated a significant increase in strength from 3 weeks (1.35 Ncm) to 6 weeks (5.17 Ncm) post-insertion (p<0.01). Measurements 6, 9 and 12 weeks post-insertion were similar to those in the 1.0-mm cavity. Initial stability of titanium mini-implants is considered necessary for immediate and early use in orthodontics, and an implant without this initial stability should be replaced or isolated until it develops the appropriate stability supported by osseointegration.

RNA interference-mediated knockdown of Smad1 inhibits receptor activator of nuclear factor κB ligand expression induced by BMP-2 in primary osteoblasts

OBJECTIVE BMP-2 induces osteoblast differentiation and activates osteoclast formation. Here, we investigated the role of Smad1, a molecule that signals downstream of BMP-2, in mediating the effects of BMP-2 on osteoclast differentiation induced by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in osteoblasts. DESIGN The effects of 1,25(OH)2D3 and BMP-2 in osteoclasts were examined using polymerase chain reaction and Western blotting to measure changes in target gene and protein expression. Immunostaining was carried out to investigate the localization of the vitamin D receptor (VDR) in the nucleus in response to BMP-2. RESULTS Stimulation with both 1,25(OH)2D3 and BMP-2 resulted in significantly greater osteoclast formation and receptor activator of nuclear factor κB ligand (RANKL) mRNA expression compared to stimulation with 1,25(OH)2D3 alone. In addition, expression of the VDR protein was increased, enhancing the activity of 1,25(OH)2D3. Interestingly, knockdown of Smad1 resulted in reduced osteoclast formation, RANKL mRNA expression, and VDR protein expression compared with control cells. Costimulation with 1,25(OH)2D3 and BMP-2 enhanced VDR localization in the nucleus. CONCLUSIONS We found that BMP-2 induced Smad1 activation, thereby influencing the localization of VDR in the nucleus in the presence of 1,25(OH)2D3 and resulting in increased RANKL mRNA expression. These effects ultimately resulted in enhanced osteoclast differentiation.

Proteases, actinidin, papain and trypsin reduce oral biofilm on the tongue in elderly subjects and in vitro

OBJECTIVE Dental plaque is a causative factor for oral disease and a potential reservoir for respiratory infection in the elderly. Therefore, there is a critical need for the development of effective methods to remove oral biofilm. The objective of this study was to investigate the effect of proteases on oral biofilm formation andremoval. DESIGN The in vivo effect of actinidin, a cysteine protease, on the removal of tongue coating was assessed after orally taking a protease tablet. Effects of the proteases trypsin, papain and actinidin on Actinomyces monospecies biofilm and multispecies biofilm that was reconstructed using a plaque sample from the tongue coating were investigated using the microtiter plate method. Antimicrobial tests and limited proteolysis of fimbrial shaft proteins were also performed to clarify underlying mechanisms of oral biofilm removal. RESULTS Tablets containing actinidin removed tongue coating in elderly subjects. Oral Actinomyces biofilm was significantly reduced by the proteases papain, actinidin and trypsin. Papain and trypsin effectively digested the major fimbrial proteins, FimP and FimA, from Actinomyces. Actinidin, papain and trypsin reduced multispecies biofilm that was reconstructed in vitro. Papain and trypsin inhibited formation of multispecies biofilm in vitro. CONCLUSIONS This study shows that proteases reduced oral biofilm in vivo in elderly subjects and in vitro, and suggests that protease digests fimbriae and inhibits biofilm formation.

Adsorption of Saliva Related Protein on Denture Materials: An X-Ray Photoelectron Spectroscopy and Quartz Crystal Microbalance Study

The aim of this study was to evaluate the difference in the adsorption behavior of different types of bovine salivary proteins on the PMMA and Ti QCM sensors are fabricated by spin-coating and sputtering onto bare QCM sensors by using QCM and X-ray photoelectron spectroscopy (XPS). SPM, XPS, and contact angle investigations were carried out to determine the chemical composition and surface wettability of the QCM surface. We discuss the quality of each sensor and evaluate the potential of the high-frequency QCM sensors by investigating the binding between the QCM sensor and the proteins albumin and mucin (a salivary-related protein). The SPM image showed a relatively homogeneous surface with nano-order roughness. The XPS survey spectra of the thin films coated on the sensors were similar to the binding energy of the characteristic spectra of PMMA and Ti. Additionally, the amount of salivary-related protein on the PMMA QCM sensor was higher than those on the Ti and Au QCM sensors. The difference of protein adsorption is proposed to be related to the wettability of each material. The PMMA and Ti QCM sensors are useful tools to study the adsorption and desorption of albumin and mucin on denture surfaces.

Application of lingual contact occlusion to complete dentures with two-layered posterior teeth: A clinical report

When two-layered artificial teeth are used, acrylic resin occlusal parts can be removed from base parts and used directly as resin patterns for casting, which facilitates fabrication of metal occlusal surfaces. Because these teeth were made of acrylic resin, it was easy to modify occlusal morphology before converting to metal. Application of two-layered artificial teeth to achieve lingual contact occlusion brought about sufficient masticatory forces and denture stability and resulted in patient satisfaction.

Preliminary Clinical Study of Initial Screening Blood Test Data onOutpatients with Burning Mouth Syndrome

Study background: The objective of study is a survey to report the prevalence of burning mouth syndrome (BMS) and to evaluated the co-morbidities associated to BMS. Subjects and Methods: A total 393 patients (54 males and 339 females; mean age 67 years; age range 27-102) were selected for this study. We carried out initial screening blood tests to these patients. Furthermore, we examined if there were previous and/or present systemic diseases and regularly taken medication by medical interview. Results: Female patients over 50 years old accounted for 89.3% (351/393). Dry mouth (330/393: 84.0%) was the most concomitant symptom with BMS. The ratio of abnormal measurements of iron was 35.9% (141/393). Zinc was 12.2% (48/393). However, the higher outrange ratio of MCV was 39.9% (157/393) and the lower outrange ratio of MCV was 8.7% (34/393). The higher outrange ratio of MCH was 36.6% (144/393) and the lower outrange ratio of MCH was 6.4% (25/393). The highest ratio of systematic disease of hypertension was 34.6% (136/393). Conclusions: We suspected that pernicious anemia may be most important factor of the BMS. Many patients had a number of systemic diseases and were taking several kinds of medicine. BMS is very complex disease, so it needs that more detailed investigation of systematic disease and habitual drug-taking is also needed.

Complete Genome Sequence of Rothia aeria Type Strain JCM 11412, Isolated from Air in the Russian Space Laboratory Mir

ABSTRACT Here, we present the complete genome sequence ofRothia aeria type strain JCM 11412, isolated from air in the Russian space laboratory Mir. Recently, there has been an increasing number of reports on infections caused by R. aeria. The genomic information will enable researchers to identify the pathogenicity of this organism.

Fabrication of all-ceramic crowns by a new method.

A new method of all-ceramic production using alumina coping has been developed. The present study investigates the influence of secondary firing (glass infiltration firing) conditions. Samples of porcelain build-up without secondary firing were also assessed. The suitability of coping that included secondary firing was found to be affected by the rate of temperature increase during the secondary firing. However, cracking developed in the fired porcelain if porcelain was built up onto secondarily-fired coping. In contrast, cracking did not occur with coping that was not secondarily fired. The bending strength after porcelain build-up was 70 MPa or higher, suggesting the possibility of clinical applications as an anterior crown. These findings establish that this is method of producing all-ceramic crowns that allows for low-cost manufacture in a short period of about 1 h.

Development of Clinical Examination Device for Complete Denture Construction.

A clinical examination device for complete denture construction was developed, and its use was investigated. The device was found to be effective for recording and examining the relation between artificial teeth and the alveolar ridge. Additionally, it was confirmed to be possible to make the occlusal rim and to arrange artificial teeth in accordance with the location of the incisive papilla and alveolar ridge. This device also allows fabrication of the base of the model parallel to the occlusal plane.

Horizontal dimensional changes in maxillary dentures made of polyethersulfone.

The purpose of this research was to investigate the horizontal dimensional variations in maxillary complete dentures fabricated with Polyethersulfone (PES) using compression molding. Dimensional changes were compared for the three different materials PES, Polysulfone (PSF), and PMMA.The results were as follows:1. In the case of the occlusion rim, all three materials displayed horizontal shrinkage both in the anteroposterior and in the left/right directions. PMMA had the largest shrinkage, followed by PSF and PES in that order.2. In the case of the denture, PSF had the largest horizontal shrinkage in the anteroposterior direction, followed by PES and PMMA in that order. In the left/right direction the shrinkage was largest for PMMA, followed by PES and PSF in that order.3. PES, like PMMA displayed a uniform shrinkage in the anteroposterior direction, with little difference observed between shrinkage in the anterior and posterior region. However, PES, like PSF, had greater shrinkage in molar region than the anterior region.