The use of a P. gingivalis-adhered ligature supported a long-lasting infection of P. gingivalis in mice, resulting in P. gingivalis-induced alveolar bone breakdown.

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.

Nitrogen-containing bisphosphonates have been well known to be inhibited farnesyl diphosphate synthase (FDPS), an enzyme in mevalonic acid metabolism, resulting in disturbance in polymerization of cytoskeleton structure in bone resorption and promotion of apoptosis in mature osteoclasts. Although bisphosphonates have been reported to activate ion transporters in native epithelium and Xenopus oocytes, little is known whether bisphosphonates affect acid hydrochronic acid extrusion in osteoclasts during bone resorption. The aim of this study was to determine the role of bisphosphonates on inhibition of hydrochronic acid extrusion in osteoclasts. Effects of zoledronic acid, a nitrogen-containing bisphosphonate, on the Cl(-) current activated by extracellular acidification were examined in two types of osteoclasts derived from RAW264.7 cells and mouse bone marrow macrophages (BMMs). Extracellular acidification induced outwardly rectifying Cl(-) currents in mouse osteoclasts. Zoledronic acid dose-dependently inhibited the acid-activated Cl(-) current. The non-nitrogen bisphosphonate etidronic acid had no effect on the acid-activated Cl(-) current. Tetracycline-induced FDPS silencing caused a significant decrease in the Cl(-) current. The inhibitor of geranylgeranyl transferase suppressed the Cl(-) current. By contrast, the inhibitory action of zoledronic acid was rescued by addition of geranylgeranyl acid, a derivative of mevalonic acid. The activity of acid-activated Cl(-) currents was dependent on expression of ClC-7 during osteoclastogenesis. These results suggest that nitrogen-containing bisphosphonates suppress the activity of osteoclastic acid-activated Cl(-) currents through FDPS inhibition, suggesting the inhibition of Cl(-) extrusion activity.

Sickly change around root divergence is determined to be a morbid state where tooth-surrounding tissues of a compound root tooth have been destroyed. A compound root tooth has a rather complicated shape when compared to a single root tooth, and it is therfore difficult to treat surrounding teeth.Causes of root divergent morbid changes are considered to be pocket formations due to the progress of chronic marginal periodontitis, abnormal states of a tooth crown such as enamel promontories, floor of pulp chamber, and lateral branch caused by pulpitis, and incomplete treatment of inside teeth. Injuries due to tooth occlusion are also considered to be a secondary cause of these morbid changes, with it is believed, occur due to a single or complex combination of the above factors.Enamel promontories, regarded as one cause of morbid change around root divergence, arrest compound tissue attachment, friggring plaque accumulation.This leads to attachment loss, followed by periodontitis. Because of this Master and Hoskins divided the cause of enamel promontories into 3 stages.Because root morbid divergent changes have many different causes, Grickman suggested that this stage should be divided into 4 stages while Lindhe & Nyman suggested division into 3 stages.Initial treatment was conducted against morbid changes in root divergence of the first molar in the lower chin on both sides, caused by enamel promontories appearing with the frequency of 30% in clinical cases in this study. Since Lindhe and Nyman suggested 2 classifications for morbid root divergence chages of the first molar on the left side of the lower chin, treatment was done using a classifications of 2-3 degrees. Al though Lindhe and Nyman sugested 3 degrees, we foused on using their 1 degree classification in treatment. We report the favorable treatment progress.