Impact of a diagnostic workshop on undergraduate teaching-learning process for the diagnosis and management of tooth restorations-A randomised controlled study.

OBJECTIVE: The aim of this study was to investigate the impact of a diagnostic workshop on undergraduate teaching-learning process for the diagnosis and management of tooth restorations. METHODS: The first stage of the study was a randomised controlled study with two parallel groups: lecture (L) and lecture coupled with a diagnostic workshop (LW). A pool of cases of tooth restorations including secondary caries and marginal defects was used for training. Theoretical knowledge, perception about the activity and practical abilities were evaluated. The second stage of the study assessed students' theoretical knowledge retention six months following intervention. All students included in the first stage of the study were exposed to LW. Hence, a new control group of students not exposed to LW was selected. One-way analysis of variance, Fisher's exact test, Kruskal-Wallis test and multilevel regression analysis were used as part of statistical analysis. RESULTS: The LW group had greater scores for the assignment of lesion severity and activity, presence of marginal defect and treatment indication than the L group (P < 0.05). Multilevel regression analysis showed a positive impact of the workshop diagnosis in the correct assessment of lesion activity (P = 0.03). There was no statistical difference between the LW and L groups in students' perception of the activity. The LW group showed greater knowledge retention after six months than the L group (P = 0.027). CONCLUSION: Lecture coupled with diagnostic workshop improved students' practical skills of diagnosis restorations and knowledge retention in the six months following intervention.

Influence of the Inoculum Source on the Cariogenicity of in vitro Microcosm Biofilms.

This study investigated the cariogenic potential of biofilms originating from different types of inoculum (saliva and dental plaque) from caries-active and caries-free individuals. Ten volunteers were selected from each caries condition for the paired collection of saliva and dental plaque. Microcosm biofilms were grown in triplicate from each inoculum on enamel specimens in 24-well plates under cariogenic challenge. After 10 days, the biofilms were collected for analysis of outcome variables: percentage of surface hardness change (%SHC) and microbiological composition of biofilms. Statistical analysis was performed using the t test, the linear multivariate analysis model and Pearson's correlation coefficients (α = 0.05). A comparative analysis between microbiological baseline data showed higher counts of mutans streptococci in plaque samples within caries-active individuals; a comparative analysis of colony-forming unit (CFU) counts between individuals with different caries status showed higher counts of acid-tolerant microorganisms and mutans streptococci in dental plaque and of acid-tolerant microorganisms in saliva. After 10 days of biofilm growth, the CFU values for total microorganisms, lactobacilli, mutans streptococci and acid-tolerant bacteria, as well as for SHC, were not statistically significant, considering the type of inoculum and caries condition (p > 0.05). A positive correlation was found for %SHC and CFU counts of acid-tolerant bacteria (r = 0.406) and lactobacilli (r = 0.379). Under the limits of this study, the cariogenic potential of biofilms, formed under identical conditions in vitro, is similar, regardless of baseline differences between the source and type of inoculum.

A clinical, microbiologic, and radiographic study of deep caries lesions after incomplete caries removal.

OBJECTIVE: Clinical, radiographic, and microbiologic changes in deep caries lesions were assessed after incomplete carious dentin removal and tooth sealing. METHOD AND MATERIALS: Thirty-two teeth with deep caries lesions were studied. Treatment consisted of incomplete excavation of the demineralized dentin, application of calcium hydroxide, and sealing for a 6- to 7-month period. The color and consistency of the dentin were clinically assessed. Differences in radiographic density were assessed by digital image subtraction. Microbiologic samples were obtained from the demineralized dentin before the temporary sealing and after the experimental period. The samples were cultivated on blood agar under aerobic and anaerobic conditions, in Mitis Salivarius agar, and Rogosa selective Lactobacillus agar. RESULTS: Two cases were lost during the study; one presented pulpal necrosis. In the other case, there was pulpal exposure during removal of provisional sealing. In all teeth, the initial demineralized dentin was soft and wet; one lesion was yellow, 21 were light brown, and eight were dark brown. After treatment, the dentin was dry, and 80.00% of specimens were hard, 16.67% were leathery, and 3.33% remained soft. The dentin was light brown in five teeth and dark brown in 25. There was a statistically significant mean difference in radiographic density (pixel intensity), 88.77 +/- 7.02 in the control areas and 94.66 +/- 6.75 in the test areas. The counts of anaerobic and aerobic bacteria, lactobacilli, and Streptococci mutans had decreased significantly by the end of treatment. CONCLUSION: Incomplete removal of carious dentin and subsequent tooth sealing resulted in the arrest of the lesions, suggesting that complete dentinal caries lesion removal is not essential to the control of caries lesions.