Nicotine increased human gingival fibroblast-mediated collagen degradation, in part through the activation of membrane-associated MMPs. Nicotine and P. gingivalis had an additive effect on human gingival fibroblast-mediated collagen degradation.

HGFs exposed to nicotine, P. gingivalis LPS, or a combination of both agents increased the expression of multiple cytokines.

This study was designed to evaluate the use of salivary cotinine, salivary thiocyanate, and expired-air carbon monoxide as biochemical validation measures for assessing the smoking status of adults. The participants were 20 known non-smokers plus 216 admitted smokers and 102 proclaimed quitters participating in a clinical trial of approaches to facilitate smoking cessation. Conventional analytical procedures were utilized. By use of data from known non-smokers and admitted smokers, the sensitivity and specificity of the validation measures were as follows: salivary cotinine, 99% and 100%; expired-air carbon monoxide, 96% and 100%; and salivary thiocyanate, 67% and 95%, respectively. The salivary cotinine and expired-air carbon monoxide tests confirmed smoking cessation for 55% and 74%, respectively, of the proclaimed quitters. The length of time since quitting was significantly related to the results observed with the latter measures. Consideration of these observations along with various practical factors suggests that expired-air carbon monoxide assays may be the validation measure of choice for most clinical trials.

Research suggests that high-quality formative assessment has a strongly positive effect upon student learning. Unfortunately, formative assessment does not appear to be frequently used in didactic dental curricula. Our hypothesis was that providing students with practice online exam questions would enable those who voluntarily took the exam to perform better on subsequent summative exams than did students who did not utilize this opportunity. A test bank of exam questions was written for dental students enrolled in two different biomedical science courses. Half the questions were arbitrarily assigned to an electronic test site; the other half were used as a written summative classroom exam taken later. Students who took the online formative exam in the first semester course scored 8.8 percent higher on the summative exam than did those who did not take the practice exam. This represents almost a full letter grade higher for the formative exam-takers. Students who took the formative online exam in the second semester course scored 5.2 percent higher on the summative exam than did the non-takers. Both of these differences were statistically significant. Under these experimental circumstances, providing formative online exams appeared to promote student performance as reflected by higher scores on the summative exams.