Rolf Attstrom

The role of the curriculum and other factors in determining the medium- to long-term attitude of the practicing dentist towards life-long learning

OBJECTIVES To investigate the significance of the undergraduate dental curriculum on the medium- to long-term attitudes of the clinician to life-long learning, and to identify demographical and professional characteristics which may influence this attitude. METHODS A specially designed questionnaire targeted 12 cohorts of dentists who qualified from Dublin Dental School and Hospital between 1994 and 2005. The curricula of the cohorts varied from fully didactic, exclusively Problem Based Learning or a hybrid for the oldest, youngest and middle graduates, respectively. Participants were questioned about current professional activities, postgraduate training, practice type, hospital affiliation, use of information services and time dedicated to continuing dental education (CDE), etc. A number of dental scenarios were proposed to determine if participants were adherent to current clinical guidelines. Additionally, a visual analogue scale assessed the overall satisfaction of dentists with their undergraduate programme and determined their opinion regarding its influence on subsequent ability to practice dentistry and keep up-to-date with scientific developments. RESULTS Contingency analysis of the association between curriculum and continuous educational data did not produce statistical significance. Dentists who work in a hospital environment spend more time on CDE (chi(2), Pearsons, P = 0.001), are more adherent to current guidelines (chi(2), Pearsons, P = 0.005) and found their undergraduate studies more enjoyable (Wilkoxon/Kruskal-Wallis, P = 0.01). CONCLUSIONS Undergraduate curriculum type was found to have very little or no effect on the graduates attitude towards life-long learning or confidence in their ability to practice dentistry. However, these attitudes did appear to be influenced by certain family, demographical and professional characteristics.

Predominant cultivable microflora of supragingival dental plaque in Chinese individuals

The aim of this study was to determine the predominant supragingival cultivable bacterial flora in Chinese individuals, using the experimental gingivitis model. A total of 11 healthy dental students, mean age 22.5 years (range 20-25) were recruited. All were provided with once-a-week dental prophylaxis and oral hygiene reinforcement for 3 weeks to ensure gingival health. In the fourth week, after prophylaxis, the participants entered a 14-day period without any plaque control. A plaque sample was collected at days 1, 3, 7 and 14 from the buccal surface of the upper right canine, second premolar, first premolar and first molar, respectively. Each sample was then dispensed in tryptic soy-broth transport medium and grown anaerobically to obtain pure cultures, which were subsequently identified. Results showed that Gram-positive cocci and rods were the predominant cultivatable species (51-61%) in the samples throughout the 14-day period; with time there was a decreasing percentage of cocci and an increasing percentage of rods. Gram-negative cocci and rods increased in proportion with the plaque age (11-37%). Streptococcus spp. were the predominant Gram-positive cocci while Actinomyces were the predominant Gram-positive rods isolated. Fusobacterium and Capnocytophaga spp. were the two most frequent Gram-negative anaerobic rods cultured. The results compared with those from other analogous studies from the West suggest the possibility of interracial differences in supragingival plaque flora.

An in vivo replica study of microbial colonization in "rapid" and "slow" dental plaque formers.

The aim of the present study was to investigate the morphological features of supragingival plaque development in «rapid» and «slow» plaque formers using the replica technique. Forty‐nine healthy volunteers were screened for their plaque formation rate after 3 days of oral hygiene abstinence using the plaque index (PI). Five subjects with the highest mean PI and six with the lowest mean PI were selected as «rapid» and «slow» plaque formers, respectively. After a series of thorough prophylaxis and oral hygiene instruction, all subjects went through a 14‐day period of no oral hygiene to allow undisturbed plaque formation. Light body silicone elastomeric impressions were taken for the upper right central incisor of each subject on day‐0, 1, 3, 7, and 14. Positive replicas were then poured from the impressions using epoxy resin and observed under a scanning electron microscope. A more complex supragingival plaque structure was seen in the day‐1 and day‐3 replicas of the «rapid» group compared to the «slow» group. From day‐7 to day‐14, during the maturation period of supragingival plaque, no discernible differences were noted between the two groups. Quantitatively, the percentage of plaque coverage on the tooth surfaces was higher in the «rapid» group than in the «slow» group in day‐1 and day‐3 replicas. These observations indicate that the morphological and topographical features of supragingival plaque in «slow» and «rapid» plaque formers differ, especially in the early developmental phase.

On saliva structures

Structures in human saliva were demonstrated using flash freezing, sectioning, fixing/staining and microscopic examinations. The microarchitecture and staining patterns of these structures and interactions with cellular material indicate the presence of the following salivary compartments: (1) a continuous water‐based electrolyte, (2) a continuous scaffold‐like network of amphiphilic macromolecules, (3) network cores with e.g. EGF/NGF‐activities, and (4) dispersed lipoid droplets. Through some acellular ingestion, networks and cores seem to engulf and pack objects like microorganisms and epithelial cells. This scavenging power and the ability of saliva to donate substances promoting wound healing provides an explanation for the instinctive sucking/licking of wounds observed in animals and humans.