Shinji Deguchi

Prevalence and risk factors for peri-implant diseases in Japanese adult dental patients

We investigated the prevalences and risk factors for peri-implant diseases in Japanese adult dental patients attending a follow-up visit at dental hospitals or clinics as part of their maintenance program. This cross-sectional multicenter study enrolled patients with dental implants who attended regular check-ups as part of a periodontal maintenance program during the period from October 2012 through September 2013. Patients with implants with at least 3 years of loading time were included in the study. The condition of peri-implant tissue was examined and classified into the following categories: healthy, peri-implant mucositis, and peri-implantitis. Patients were also evaluated for implant risk factors. A total of 267 patients (110 men, 157 women; mean age: 62.5 ± 10.7 years) were analyzed. The prevalence of patient-based peri-implant mucositis was 33.3% (n = 89), and the prevalence of peri-implantitis was 9.7% (n = 26). Poor oral hygiene and a history of periodontitis were strong risk factors for peri-implant disease. The present prevalences were lower than those previously reported. The quality of periodontal therapy before and after implant installation and patient compliance and motivation, as indicated by plaque control level, appear to be important in maintaining peri-implant tissue health.

Experimental diabetes accelerates accumulation of fluorescent pigments in rat trigeminal neurons

The purpose of this study was to investigate autofluorescent pigment granules (lipofuscin, ceroid) in the trigeminal neurons (TN) during aging and streptozotocin-induced diabetes. Four young adult male rats were injected with streptozotocin (STZ; 50 mg/kg) to produce diabetes (DM), for comparison with four young uninjected control rats and four aged rats (90 weeks old). Eight weeks after STZ injection, all rats were fixed with 4% paraformaldehyde, and paraffin sections of TN were prepared and observed by fluorescence microscopy. We found the number of neurons with autofluorescent pigments had increased to 30.38% of the total in DM compared to 8.98% in the control group, and 25.36% in the aged rats. The area of autofluorescence within those neurons was 16.84% in aged rats, 13.02% in DM and 4.45% in the controls. Thus, DM caused accelerated accumulation of fluorescent granules in trigeminal neurons, and this change may show that premature aging contributes to neuronal functional decline and morphological change.

The influence of β-tricalcium phosphate blocks containing extracellular matrix on osteogenic differentiation of rat bone marrow stromal cells.

BACKGROUND The aim of the present study is to assess the osteogenic differentiation of rat bone marrow stromal cells (RBMCs) in β-tricalcium phosphate (β-TCP) blocks containing extracellular matrix (ECM) produced by human alveolar bone periosteal cells (HABPCs). METHODS HABPCs were cultured in β-TCP blocks for 1 week (group 1) and 2 weeks (group 2). β-TCP blocks containing ECM were then created by drying the blocks for 3 days. RBMCs were cultured in the blocks containing ECM for 2 weeks. In the control group, RBMCs were cultured in β-TCP blocks alone for 2 weeks. HABPCs and RBMCs in the blocks were examined by histologic and immunohistochemical analyses. RESULTS Histology revealed a significantly higher number of HABPCs in the group 2 blocks than in the group 1 blocks. HABPCs produced several bone matrix proteins in the blocks, and these positive reactions in group 2 were significantly higher than in group 1. Both groups showed a significantly higher number of RBMCs than the control group. RBMCs produced osteopontin and osteocalcin in the blocks, and these positive reactions were significantly higher in both test groups than in the control group. The number of osteocalcin-positive reactions was higher in group 2 than in group 1. CONCLUSION Osteogenic differentiation of RBMCs cultured for 2 weeks in β-TCP blocks containing ECM was significantly higher than that of cells cultured for 1 week or without ECM.

Comparison on the Effects of Oral Hygiene Using the Different Toothbrush in the Gingival Recession Models.

本研究では, 歯ブラシヘッド部が小型化された新型反回転式電動歯ブラシにおける歯肉退縮模型の清掃効果についての検討を行った。実験に使用した歯ブラシは, 電動歯ブラシとして毛束が2列10束よりなる従来型, 2列6束よりなる新型の反回転式電動歯ブラシインタープラークを, また, 手用歯ブラシとしてGUM#211を使用した。歯肉退縮模型は, 1.5mm歯肉退縮模型と, 3.0mm歯肉退縮模型の2種類を用いた。また, 正常歯肉模型を用いての検討も行った。清掃方法として, 電動歯ブラシ群においては歯面に対し毛束を直角にあて1歯15秒間のブラッシングを行わせ, 手用歯ブラシにおいては, スクラッビング法に準じた方法で1歯15ストロークでブラッシングを行わせた。ブラッシング圧は, 簡易加重測定装置を用い, 250gの一定圧で, 各模型5回計測をした。人工プラーク除去率の測定方法は, 規格撮影装置で撮影後, コンピューターに取り込み, NIH imageを用いて規格面積中の残存プラークの面積を測定した。統計学的検索は, 2元配置分散分析を用いた。全プラーク除去率は, 正常歯肉模型および1.5mm歯肉退縮模型において従来型>新型>手用歯ブラシの順に, 3.0mm歯肉退縮模型においては従来型>手用>新型歯ブラシの順に, プラーク除去率が高い値を示した。歯肉退縮模型では大臼歯部隣接面において新型歯ブラシが他の歯ブラシと比較して高いプラーク除去率を示す傾向が認められた。