Rotational movements of mandibular two-implant overdentures.

OBJECTIVES: Clinicians have reported that their patients complain that their mandibular two-implant overdentures (IOD) rotate. Therefore, we studied the frequency and severity of rotation of IODs with two-ball attachments, how rotation may influence perceived satisfaction ratings of chewing ability, and the factors that are involved in the rotation of IODs. MATERIAL AND METHODS: Seventy-nine participants were recruited and asked to rate their general satisfaction of their IODs, as well as their ability to chew foods, the existence of any mandibular denture rotation, and to what degree denture rotation bothered them. Data on participant sociodemographic, anatomical, and prosthesis characteristics were also collected. Student's t-test and logistic regression analyses were performed to analyze the differences between participants who did (R group) and did not report (NR group) denture rotation. RESULTS: Thirty-seven of 79 participants were aware of rotational movement in their IODs. These patients were significantly less satisfied with their chewing ability than those who felt no rotation (69.1 mm R group vs. 82.9 mm), and discomfort caused by the rotation bothered them moderately (39/100 mm). The multivariate logistic regression analysis revealed that the arrangement of the anterior teeth and the length of the denture are significantly associated with awareness of denture rotation. Thirty-eight percent in the R group and 31% in the NR group had non-scheduled visits. CONCLUSIONS: Rotational movement with a mandibular two-IOD has a negative effect on perceived chewing ability and is associated with anterior tooth arrangement and denture length.

Crystalline low band-gap alternating indolocarbazole and benzothiadiazole-cored oligothiophene copolymer for organic solar cell applications.

A low band-gap alternating copolymer of indolocarbazole and benzothiadiazole-cored oligothiophene demonstrated balanced crystallinity and solubility; a solar cell combining this polymer with PC(61)BM in a preliminary test demonstrated power conversion efficiencies of 3.6%.

Monitoring recruitment success and cost in a randomized clinical trial.

Recruitment of older adults into research studies is challenging and, as a consequence, the recruitment period is often extended and more expensive than planned. This study monitored the effectiveness (number of subjects attracted) and cost of different recruitment strategies when recruiting edentulous elderly adults. Socio-demographic data were gathered and compared to 2001 Canadian census data. Advertisements in major Montreal newspapers attracted the most people (24.3%). However, the most economical recruitment method proved to be placement of ads in senior newspapers (dollar 73.74 per subject). The information gathered in this study will assist others in planning recruitment strategies for edentulous elderly populations.