Effect of initial placement level and wall thickness on maintenance of the marginal bone level in implants with a conical implant-abutment interface: a 5-year retrospective study

PURPOSE: Implant wall thickness and the height of the implant-abutment interface are known as factors that affect the distribution of stress on the marginal bone around the implant. The goal of this study was to evaluate the long-term effects of supracrestal implant placement and implant wall thickness on maintenance of the marginal bone level. METHODS: In this retrospective study, 101 patients with a single implant were divided into the following 4 groups according to the thickness of the implant wall and the initial implant placement level immediately after surgery: 0.75 mm wall thickness, epicrestal position; 0.95 mm wall thickness, epicrestal position; 0.75 mm wall thickness, supracrestal position; 0.95 mm wall thickness, supracrestal position. The marginal bone level change was assessed 1 day after implant placement, immediately after functional loading, and 1 to 5 years after prosthesis delivery. To compare the marginal bone level change, repeated-measures analysis of variance was used to evaluate the statistical significance of differences within groups and between groups over time. Pearson correlation coefficients were also calculated to analyze the correlation between implant placement level and bone loss. RESULTS: Statistically significant differences in bone loss among the 4 groups (P<0.01) and within each group over time (P<0.01) were observed. There was no significant difference between the groups with a wall thickness of 0.75 mm and 0.95 mm. In a multiple comparison, the groups with a supracrestal placement level showed greater bone loss than the epicrestal placement groups. In addition, a significant correlation between implant placement level and marginal bone loss was observed. CONCLUSIONS: The degree of bone resorption was significantly higher for implants with a supracrestal placement compared to those with an epicrestal placement.

Prevalence and risk factors of irritable bowel syndrome in Korean high school students / 한국역학회지

BACKGROUND AND OBJECTIVES: Irritable bowel syndrome (IBS) is prevalent in the general population, but there are few reports on bowel habits and IBS in high school students in Korea. This study aims to describe the prevalence of IBS in high school students in Korea and to investigate the influence of lifestyle factors including dietary habits, on the IBS. This study also investigates relationship between anxiety, depression and IBSprevalence. SUBJECTS AND METHODS: This study is a cross-sectional study on 1,018 students (451 males and 567 females) form freshman to senior of a high schools in Seoul. All students were requested to fill in a self-reported questionnaire. IBS was diagnosed based on the Rome II criteria. Those having past medical history of organic gastrointestinal disorders and any one of the 'alarm factors'(e.g. continuous hematochezia, weight loss, or anemic symptom) were excluded from the IBS group. For the evaluation of risk factors on the IBS, we surveyed dietary habit, health behavior, past medical history, the Hollingshed index for the measurement of socioeconomic status, Beck's Anxiety Inventory for the anxiety, and the Children's Depression Inventory for the depression. RESULTS: The prevalence of IBS was 19.1%. Family history of abdominal discomfort (odds ratio 2.07, 95% 1.46-2.92) and having night snack (odds ratio 1.46, 95% CI 1.09-1.94) were significantly different between the IBS group and non-IBS group. There was a linear trend towards the higher prevalence of IBS with fewer hours of exercise (odds ratio 0.99, 95% CI 0.95-1.04). Menstruation, stress, and irregular eating were the significant provocation factors of IBS. Anxiety and depression was not significantly higher in in the IBS group. CONCLUSIONS: Prevalence of the IBS in high school students from this study was higher compared with those reported in college students in Korea. This study shows that family history, dietary factors, lifestyle, and grade were significantly related to IBS. From our study, we found that there are multifaceted health aspects required to reduce symptoms, such as dietary education and encouragement to change lifestyle for controlling stress.