Satoshi Shirakawa

Evaluation of a novel immunochromatographic device for rapid and accurate clinical detection of Porphyromonas gingivalis in subgingival plaque

UNLABELLED An important goal for the improved diagnosis and management of infectious and inflammatory diseases, such as periodontitis, is the development of rapid and accurate technologies for the decentralized detection of bacterial pathogens. The aim of this prospective multicenter study was to evaluate the clinical use of a novel immunochromatographic device with monoclonal antibodies for the rapid point-of-care detection and semi-quantification of Porphyromonas gingivalis in subgingival plaque. Sixty-three patients with chronic periodontitis and 28 periodontally healthy volunteers were subjected to clinical and microbiological examinations. Subgingival plaque samples were analyzed for the presence of P. gingivalis using a novel immunochromatography based device DK13-PG-001, designed to detect the 40k-outer membrane protein of P. gingivalis, and compared with a PCR-Invader method. In the periodontitis group, a significant strong positive correlation in detection results was found between the test device score and the PCR-Invader method (Spearman rank correlation, r=0.737, p<0.0001). The sensitivity, specificity, and positive and negative predictive values of the test device were 96.2%, 91.8%, 90.4% and 96.7%, respectively. The detection threshold of the test device was determined to be approximately 10(4) (per two paper points). There were significant differences in the bacterial counts by the PCR-Invader method among groups with different ranges of device scores. With a cut-off value of ≥0.25 in device score, none of periodontally healthy volunteers were tested positive for the subgingival presence of P. gingivalis, whereas 76% (n=48) of periodontitis subjects were tested positive. There was a significant positive correlation between device scores for P. gingivalis and periodontal parameters including probing pocket depth and clinical attachment level (r=0.317 and 0.281, respectively, p<0.01). The results suggested that the DK13-PG-001 device kit can be effectively used for rapid, chair-side detection and semi-quantification of P. gingivalis in subgingival plaque. TRIAL REGISTRATION UMIN Clinical Trials Registry (UMIN-CTR) UMIN000011943.

Bone formation by human umbilical cord perivascular cells

We investigated the possibility of employing human umbilical perivascular cells (HUCPVCs) within the context of finding an alternative source of mesenchymal stromal cells (MSC) for bone tissue engineering. Since it has previously been reported that conditioned medium (CM) from osteogenic bone marrow (BM) MSCs can potentiate osteogenic differentiation in a secondary cell population, we also employed BM-MSCs to generate CM to stimulate osteogenesis in the HUCPVCs. The BM-MSCs were a commercially available immortalized human cell line. In vitro assays showed negligible levels of osteogenic gene expression in HUCPVCs compared to BM-MSC, but alkaline phosphatase was detected when HUCPVC were cultured in osteogenic medium in the presence of CM from BM-MSC. An in vivo assay employing a rat calvarial osteotomy defect, together with a collagen sponge scaffold, showed that HUCPVCs provided statistically significant bony repair compared to controls. BM-MSC loaded scaffolds were not statistically different from either controls or HUCPVCs. The addition of BM-MSC CM to HUCPVCs also produced no statistically significant difference to the bone formed by HUCPVCs alone. Our results demonstrate that the in vitro assays employed did not predict in vivo outcomes, and that the BM-MSC cell line employed, or CM from such cells, provided no osteogenic advantage over the use of HUCPVCs alone.

Effect of the Keratinized Mucosa Width on the Health Status of Periimplant and Contralateral Periodontal Tissues: A Cross-sectional Study.

Introduction:The purpose of this study was to examine whether the width of keratinized mucosa (WKM) is associated with the health status of tissue surrounding dental implants and the contralateral teeth. Materials and Methods:Sixty patients who received implant-fixed unilateral prostheses in the premolar or molar region were recruited for the study. The following parameters were measured for each implant and contralateral tooth: WKM, gingival index (GI), probing pocket depth (PPD), bleeding on probing (BOP), pus discharge, plaque accumulation (PA), gingival recession (GR), and difficulty of brushing. The effect of the WKM on the health status of the surrounding tissue was evaluated by comparing the different WKM groups (WKM < 2 mm vs WKM ≥ 2 mm). Results:Implants with a WKM <2 mm demonstrated significantly greater PPD, PA, and a higher rate of BOP compared with implants with a WKM ≥2 mm. There was significantly greater GR in contralateral teeth with a WKM <2 mm compared with a WKM ≥2 mm. In addition, implant sites had a higher rate of BOP compared with the contralateral teeth. Conclusions:Inadequate keratinized mucosa decreased cleansibility of implant sites and increased mucosal inflammation. There is a possibility that PA in implant sites caused more pronounced inflammatory response compared to contralateral tooth.

Full‐mouth scaling and root planing combined with azithromycin to treat peri‐implantitis

BACKGROUND Full-mouth scaling and root planing combined with azithromycin is clinically and bacteriologically effective for the treatment of chronic periodontitis. This study aimed to investigate the clinical and bacteriological effects of this combination treatment in patients with peri-implantitis. METHODS Twenty adult patients with both chronic periodontitis and peri-implantitis were randomly divided into two groups (10: test, 10: control). All patients underwent full-mouth scaling and root planing but the test group received azithromycin for 3 days before the procedure. The probing depth, bleeding on probing, and the gingival index were assessed clinically. Bacterial samples were obtained before treatment at 1 week and 1, 3, 6, 9 and 12 months after treatment. Quantitative and qualitative analyses were performed using the polymerase chain reaction Invader method. RESULTS All clinical parameters showed better improvement in both periodontitis and peri-implantitis in the test group. Periodontal bacteria were more effectively reduced in the test group, but gradually increased around implants 6 months after treatment and natural teeth 9 months after treatment. CONCLUSIONS Full-mouth scaling and root planing combined with azithromycin was temporarily useful for the treatment of peri-implantitis. Clinical improvements were maintained for about 9 months but periodontal bacteria increased again 6 months after treatment.

Clinical Usefulness of Novel Immunochromatographic Detection Device for Porphyromonas gingivalis in Evaluating Effects of Scaling and Root Planing and Local Antimicrobial Therapy

BACKGROUND The authors have previously reported development of a novel immunochromatographic device (DK13-PG-001) for specific detection of Porphyromonas gingivalis (Pg). In this study, clinical usefulness of the detection device during periodontal therapy is presented. METHODS The multicenter study was conducted with 62 patients contributing 118 periodontitis sites with probing depth (PD) of 4 to 9 mm. Subgingival plaque samples were used for detection of Pg by DK13-PG-001 and the PCR-invader method at: 1) baseline (BL); 2) reevaluation (RE; after scaling and root planing); and 3) final evaluation (FE; after local drug delivery system). Periodontal examinations were performed concurrently with the test for Pg detection. Plasma immunoglobulin G (IgG) titers against Pg were also determined in patients using an enzyme-linked immunosorbent assay. RESULTS DK13-PG-001 score and number of Pg by the PCR-invader method showed a strong correlation (r = 0.862) at three stages during periodontal therapy (n = 354). High sensitivity and specificity of DK13-PG-001, in comparison with the PCR-invader method, were shown. A significant correlation was found among device score, number of Pg by the PCR-invader method, and PD and clinical attachment level at BL and RE. Plasma IgG titers against Pg were significantly reduced at FE in comparison with BL. Weak but significant correlations between IgG titers and device scores were shown at BL and FE. CONCLUSION Results suggest the DK13-PG-001 device is a useful tool for detection of Pg in dental offices and can aid clinical evaluation of the extent of periodontitis and therapeutic efficacy.