Je Dyson

A Randomized Trial on Root Caries Prevention in Elders

Root caries is common in institutionalized elders, and effective prevention methods are needed. This clinical trial compared the effectiveness of four methods in preventing new root caries. From 21 residential homes, 306 generally healthy elders having at least 5 teeth with exposed sound root surfaces were randomly allocated into one of four groups: (1) individualized oral hygiene instruction (OHI); (2) OHI and applications of 1% chlorhexidine varnish every 3 months; (3) OHI and applications of 5% sodium fluoride varnish every 3 months; and (4) OHI and annual applications of 38% silver diamine fluoride (SDF) solution. Two-thirds (203/306) of the elders were followed for 3 years. Mean numbers of new root caries surfaces in the four groups were 2.5, 1.1, 0.9, and 0.7, respectively (ANOVA, p < 0.001). SDF solution, sodium fluoride varnish, and chlorhexidine varnish were more effective in preventing new root caries than giving OHI alone.

Blended learning, knowledge co-construction and undergraduate group work

(designated ‘Learning from Lives’ [LFL]), and the other with medical and interprofessional students (‘Interprofessional Learning Pathway’ [IPLP]). Learning from Lives aims to provide a practical, in-depth understanding of the nature and effect of impairment on people’s lives and societal reactions towards disability and is situated at the beginning of clinical rotation. In IPLP medical students work with 13 other student health and social care professionals as they follow an authentic patient journey (Callum) aimed at developing their understanding of the roles, cultures and beliefs of their colleagues. In LFL, the students, working in clinical partnerships, meet with patients face-to-face in their homes or clinical settings. They are also able to access a pilot online patient journey. The same patient journey was used in the virtual IPLP. Ethical permission was not required. Why the idea was necessary The idea in LFL arose because service problems in accessing patients made it difficult for us to ensure that students were able to meet their learning outcomes. We chose to provide online patient and professional cases. Student evaluation suggested that e-learning cases enriched the module, but did not replace face-to-face learning. The patient journey was scripted from the original scenario, with each health professional talking about Callum and his or her role in his care. This was in contrast to the IPLP, where Callum was text-based and his story was told objectively. Student evaluation commented that it would be beneficial to have video and audio clips intertwined with the text-based scenario. What was done Video and audio clips were professionally created using an actress and scripts derived from the original text-based version. In LFL medical students were able to watch four introductory clips depicting Callum’s journey from his mother’s and his paediatrician’s perspectives. They then had a restricted choice of viewing further clips of the mother discussing particular issues with other professionals involved in his care. Students had to identity their reasons for their choice of clips. Once they had given this information, they were able to view the clips, which added to the story. In IPLP the video clips were divided across four episodes. The clips were chosen to supplement and enhance the storyline at each point. Evaluation of results and impact Students’ evaluation of LFL supported the idea of using of e-cases, but the comparison of e-cases and the experience of face-to-face contact showed clearly that e-cases could not replace such contact. Students considered that e-learning precluded their ability to utilise the body language and verbal cues that are available in face-to-face contact. By contrast, students’ participating in IPLP valued the multimedia input, stating that it had enhanced their learning by providing them with insights into other perspectives. Evidence of the students’ connection with the mother’s anxiety and concerns was apparent only in discussions with the multimedia student group. Evaluations suggest that multimedia clips serve to enrich each module, but cannot replace face-to-face or text-based cases.

Vibration characteristics of dental high-speed turbines and speed-increasing handpieces

OBJECTIVES Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dental personnel and iatrogenic enamel cracking in teeth. However, methods for measuring dental handpiece vibrations have previously been limited and information about vibration characteristics is sparse. This preliminary study aimed to use a novel approach to assess the vibrations of unloaded high-speed handpieces in vitro. METHODS Maximum vibration displacement amplitudes of five air turbines and two speed-increasing handpieces were recorded whilst they were operated with and without a rotary cutting instrument (RCI) using a scanning laser vibrometer (SLV). RESULTS RCI rotation speeds, calculated from frequency peaks, were consistent with expected values. ANOVA statistical analysis indicated significant differences in vibrations between handpiece models (p<0.01), although post hoc tests revealed that differences between most individual models were not significant (p>0.11). Operating handpieces with a RCI resulted in greater vibrations than with no RCI (p<0.01). Points on the head of the handpiece showed greater vibration displacement amplitudes than points along the body (p<0.01). CONCLUSIONS Although no single measurement exceeded 4 microm for the handpieces in the current test setup (implying that these vibrations may be unlikely to cause adverse effects), this study has formed the basis for future work which will include handpiece vibration measurements whilst cutting under clinically representative loads.

Effect of contamination and decontamination on adhesion of a resin-modified glass-ionomer cement to bovine dentin.

PURPOSE To determine the adhesion of resin-modified glass-ionomer cement to bovine dentin under contaminated and decontaminated conditions. MATERIALS AND METHODS Forty-five bovine mandibular incisors were used. The surfaces of bovine dentin specimens were subjected to Temp-bond, dental handpiece lubricant (contamination), Hibiscrub, chlorhexidine or pumice (decontamination), as well as contamination followed by decontamination. From these, 14 test groups were created to investigate the effects of these variables on the microtensile bond strength of a resin-modified glassionomer cement to dentin. In addition, scanning electron microscopy was performed to examine the effects of contamination and decontamination procedures on the dentin surfaces. The data were analyzed by one-way ANOVA, Kruskal-Wallis, and Mann-Whitney tests. RESULTS SEM examination showed visible differences between the control group and dentin contaminated with Temp-bond or handpiece lubricant. All the contamination and decontamination test agents when used alone - except Hibiscrub - showed significant reductions in bond strength when compared to the control (p < 0.001). All the test groups subjected to contamination followed by decontamination showed a significantly reduced bond strength (p < 0.001) when compared to the control, with the exception of the handpiece lubricant/Hibiscrub combination. CONCLUSION Under the conditions tested, Temp-bond, handpiece lubricant, chlorhexidine, and pumice may have an adverse effect on the bonding of resin-modified glass ionomer to dentin. Hibiscrub was effective in decontaminating handpiece lubricant but not Temp-bond.

An approach to the preclinical teaching of removable partial-denture technique☆

Abstract An account is given of an undergraduate course in removable partial-denture technique which involves teaching in both the clinic and the technology laboratory. A simple phantom head consisting of a modified fixed condylar path articulator is described and its use in teaching the course is discussed.