Peri-implant diseases are known as undesirable conditions that can occur after implant therapy. Although several risk indicators are becoming clear, the causes of peri-implant diseases have not been completely investigated. The purpose of this review was to summarize the prevalence and risk indicators for peri-implant diseases by referring to current papers from various angles. Many studies have reported the varied prevalence of peri-implant mucositis (23.9%–88.0% at the patient level and 9.7%–81.0% at the implant level) and peri-implantitis (8.9%–45% at the patient level and 4.8%–23.0% at the implant level). Additionally, several studies concluded that poor oral hygiene and lack of regular maintenance were strongly correlated with the development of both peri-implant mucositis and peri-implantitis. Diabetes and a history of periodontitis were revealed as risk indicators for peri-implantitis. However, there was no definitive conclusion about the correlations between peri-implant diseases and other factors such as smoking, the shape of the implant superstructure, and the condition of the keratinized mucosa. Further studies useful for evidence-based decision-making are needed for predictable implant therapy in the long term.

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Purpose: Removable dentures are a reasonable option for prosthetic treatment. However, continuous residual ridge resorption and reline procedures are inevitable owing to the strong pressure exerted on the mucosa or inappropriate pressure distribution. This study aimed to elucidate the association between the gonial angle on orthopantomogram (GAO) with occlusal force and reline frequency in removable partial denture wearers. Methods: Participants were patients who had previously received removable partial denture treatment for a free-end defect. Age, sex, number of remaining teeth, remaining opposing teeth, and occlusal support were investigated. GAO was measured using panoramic radiographs. The mean relining interval was calculated as the mean number of days between denture insertion and the first relining or subsequent relining. The association between the mean relining interval and each factor was investigated. Results: Sixty-five subjects (33 females) were analyzed. The median value of the mean relining interval was 533.3 days, and the median GAO was 123º. There was a significant positive correlation between the mean relining interval and GAO (rs = 0.335). The number of remaining opposing teeth and occlusal support exhibited weak negative correlations with mean relining interval (rs = -0.187 and -0.214, respectively). Multivariate analysis using a generalized linear model showed that GAO was a significant explanatory variable for the mean relining interval. Conclusions: Within the limitations of this study, GAO was found GAO was found to contribute to the increased frequency of relining due to ridge resorption in patients with a small GAO.

Coenzyme Q (Ubiquinone) is widely distributed in the animal, plant and microorganism kingdoms including human beings, and is now generally recognized to have an important role in the electron transport system. However, the physiological actions of this substance have not yet exactly known. The objectives of this study are to clarify the protective and restorative effects of coenzyme Q on the hypercitricemia arising from alloxan treatment.Young male rats of the Wistar strain, weighing 150 to 200gm. , were used. Rats were made diabetic by the intravenous administration by tail vein in doses of 80mg. of alloxan monohydrate/Kg. of body weight after deprivation of food overnight. At 24 hours following alloxanization, hypercitricemia and hyperglycemia were apparent.Single intraperitoneal administration of 100mg. coenzyme Q7/Kg. of body weight given before alloxaninzation protected against both the hypercitricemia and hyperglycemia arising from alloxan.As a restorative effect of coenzyme Q, the diabetic rats were used 2-4 weeks after receiving alloxan.The rats received 2 intramuscular injections of coenzyme Q7 at 12 hours interval in total doses of 400mg/l Kg. of body weight. At 24 hours later after the first administration of coenzyme Q7 the hypercitricemia induced by alloxan trended to reduce toward the normal level, but there was no significant effect on hyperglycemia.