Features of an effective operative dentistry learning environment: students' perceptions and relationship with performance.

OBJECTIVE: Students' perceptions of their learning environment influence the quality of outcomes they achieve. Learning dental operative techniques in a simulated clinic environment is characterised by reciprocal interactions between skills training, staff- and student-related factors. However, few studies have examined how students perceive their operative learning environments and whether there is a relationship between their perceptions and subsequent performance. Therefore, this study aimed to clarify which learning activities and interactions students perceived as supporting their operative skills learning and to examine relationships with their outcomes. METHODS: Longitudinal data about examples of operative laboratory sessions that were perceived as effective or ineffective for learning were collected twice a semester, using written critical incidents and interviews. Emergent themes from these data were identified using thematic analysis. Associations between perceptions of learning effectiveness and performance were analysed using chi-square tests. RESULTS: Students indicated that an effective learning environment involved interactions with tutors and peers. This included tutors arranging group discussions to clarify processes and outcomes, providing demonstrations and constructive feedback. Feedback focused on mistakes, and not improvement, was reported as being ineffective for learning. However, there was no significant association between students' perceptions of the effectiveness of their learning experiences and subsequent performance. CONCLUSIONS: It was clear that learning in an operative technique setting involved various factors related not only to social interactions and observational aspects of learning but also to cognitive, motivational and affective processes. Consistent with studies that have demonstrated complex interactions between students, their learning environment and outcomes, other factors need investigation.

Intrinsic rewards experienced by a group of dentists working with underserved populations.

BACKGROUND: The aim of this study was to explore, using qualitative methods, the intrinsic reasons why dentists work with underserved groups. Minority and marginalized groups of Australians suffer a greater burden of dental disease than the general population due to disparities in accessing care. Recruitment and retention of dentists to care for underserved groups is problematic due to personal, professional and structural reasons. What drives dentists to work with underserved groups is not widely known. METHODS: Sixteen dentists were recruited using 'snowball' purposeful sampling. Semi-structured in-depth interviews were conducted. Thematic analysis was conducted on the transcriptions to identify themes. RESULTS: Five key themes emerged: (1) 'tapped on the shoulder', being personally approached or invited; (2) 'dental school experience', the challenges faced as a student; (3) 'empathic concern', the non-judgemental expressions of care toward others; (4) 'resilience', the ability to bounce back after setbacks; (5) 'intrinsic reward', the personal gain and satisfaction received. This study focuses on the intrinsic rewards which were found to be simple, unexpected, and associated with relieving pain, community engagement and making a difference. CONCLUSIONS: Emphasizing personal fulfilment and intrinsic reward could be useful when promoting dentistry as a career and when encouraging graduates to consider working with disadvantaged groups.

Reorientating dental curricula to reflect a minimally invasive dentistry approach for patient-centred management.

Minimally invasive dentistry (MID), together with patient-centred care (PCC), can be considered central to patient management. These approaches have been incorporated in the structure of various dental curricula and indeed formally assessed. However, there is limited evidence that students have an integrated skill-set and are able to apply these skills when providing direct patient care within the clinical setting. Assessment of students' application of core clinical skills has identified numerous deficiencies that need to be addressed. The revised Bachelor of Dental Surgery curriculum at the School of Dentistry, The University of Adelaide, provides an example of how MID, underpinned by PCC, can be presented throughout a dental curriculum. Essentially, MID and PCC are not considered as separate subjects but as a patient management approach that is 'woven into the whole fabric' of the curriculum. The programme relies on the development of empathic communication skills that enable students to obtain key patient information, including their patients' values, beliefs, needs, preferences and expectations, thereby allowing management to be tailor-made. As a result, patients are empowered to be a part of the oral health care team. The Adelaide undergraduate dental curriculum consists of one clinical stream called Dental Science and Practice (DSP), that promotes the application of student knowledge, skills and behaviours in the clinical setting. Vertical and horizontal integration, aligned with an integrated approach to assessment, drives the learning throughout the programme. Clearly-defined outcomes are introduced by Integrated Learning Activities (ILAs) that provide a focus for associated learning activities (e.g. class meetings, tutorials, simulation laboratories, etc). The aim of this approach to learning and teaching is to ensure the required learning outcomes are achieved. It also requires coordinated teaching teams including trained external tutors who clearly understand all aspects of MID and PCC within the curriculum structure.

Validity of scores from communication skills instruments for patients and their dental student-clinicians.

The development of appropriate communication skills by healthcare providers is central to providing quality patient-centred care. Patients can provide valuable feedback to practitioners about their clinical communication. However, in oral health care, their involvement is uncommon and instruments specific for communication in oral health care have not been available. Recently, two complementary instruments have been developed by the Faculty of Dentistry, University of Manitoba for evaluating student-clinicians' clinical communication: one for patient evaluation and one for student self-evaluation. The aim of the current study was to provide validity evidence for the scores related to the internal structure of the revised 2007 versions of these instruments in two dental clinical/education contexts, namely the Universities of Manitoba, Canada (UM) and Adelaide, Australia (UA). The proposed factor structure and loadings, and their stability across contexts were assessed using confirmatory factor analysis, and the adequacy of the internal consistency reliability of the scores was analysed using Cronbach's alpha. The factor structure of the current 2007 versions of the patient and student instruments, derived from the previously developed longer versions of these instruments, was confirmed and was consistent across the two clinical/educational contexts. A model of partial invariance provided the best fit for these data due to variations in the magnitude of the factor loadings between sites. The internal consistency reliability of scores was high with a range of 0.88-0.97. In conclusion, the current study provides preliminary evidence regarding the validity of the scores of the current 2007 instruments, in terms of the internal structure, as measuring the five factors well. Replication of the factor structure of these instrument scores with more participants at both UA and other institutions is required.

Acquiring psychomotor skills in operative dentistry: do innate ability and motivation matter?

OBJECTIVE: The acquisition of psychomotor skills is a key competence in the practice of dentistry, and innate abilities and motivation have been shown to influence motor performance. However, the explicit integration of these factors into the design of research projects about skill acquisition in dentistry has been limited. Therefore, the purpose of this study was to provide a comprehensive analysis of how dental students' abilities and motivation affected their performance in an operative task. METHODS: A longitudinal study with two cohorts of dental students was conducted in laboratory classes forming part of an operative technique course. A range of standardised psychometric tests was used to assess different abilities before completing a cavity preparation on Frasaco teeth. This was followed immediately by completion of an Intrinsic Motivation Inventory. RESULTS: Low but statistically significant correlations (P<0.05) were found between dental performance and psychomotor ability (r=0.22), and also dental performance and motivation (r=0.19). A significant difference (P<0.05) was found in the grades obtained for the cavity preparation exercise in one cohort between students with higher levels of psychomotor ability compared with those with lower levels (Tracing scores) (P<0.05). No significant differences in grades obtained for the cavity preparation exercise were found between students with higher and lower levels of motivation. CONCLUSION: Both innate psychomotor ability and motivation showed only weak positive associations with dental performance on cavity preparation exercises. Our study suggests that student-related factors only provide limited information to explain differences in performance or to be useful as specific predictors of future performance by individuals.

Differences in mouse strain influence leukocyte and immunoglobulin phenotype response to Porphyromonas gingivalis.

This study examined the nature of the infiltrating cells in Porphyromonas gingivalis-induced lesions and immunoglobulins in the serum samples of BALB/c (H-2d), C57BL6 (H-2b), DBA/2J (H-2d) and CBA/CaH (H-2k) mice. Mice were immunized intraperitoneally with P. gingivalis outer membrane antigens or sham-immunized with phosphate-buffered saline followed by subcutaneous challenge with live organisms 1 week after the final immunization. The resulting skin abscesses were excised 7 days later, cryostat sections cut and an immunoperoxidase method used to detect the presence of CD4+ and CD8+ T-cell subsets, CD14+ macrophages and CD19+ B cells. Peroxidase positive neutrophils and IgG1- and IgG2a-producing plasma cells were also identified. Anti P. gingivalis IgG1 and IgG2a subclass antibodies were determined in serum obtained by cardiac puncture. Very few CD8+ T cells and CD19+ B cells were found in any of the lesions. The percentages of CD4+ cells, CD14+ cells and neutrophils were similar in lesions of immunized BALB/c and C57BL6 mice, with a trend towards a higher percentage of CD14+ cells in sham-immunized mice. The percentage of CD14+ cells was higher than that of CD4+ cells in immunized compared with sham-immunized DBA/2J mice. The percentages of CD4+ and CD14+ cells predominated in immunized CBA/CaH mice and CD4+ cells in sham-immunized CBA/CaH mice. The percentage of neutrophils in immunized CBA/CaH mice was significantly lower than that of CD14+ cells and CD4+ cells in sham-immunized mice. IgG1+ plasma cells were more dominant than IgG2a+ cells in immunized BALB/c, C57BL6 and DBA/2J mice, whereas IgG2a+ plasma cells were more obvious in sham-immunized mice. IgG2a+ plasma cells were predominant in immunized and sham-immunized CBA/CaH mice. In the serum, specific anti-P. gingivalis IgG2a antibody levels (Th1 response) were higher than IgG1 levels (Th2 response) in sham-immunized CBA/CaH and DBA/2J mice. In immunized BALB/c mice, IgG2a levels were lower than IgG1 levels, while IgG2a levels were higher in immunized C57BL6 mice. In conclusion, this study has shown differences in the proportion of infiltrating leukocytes and in the subclasses of immunoglobulin produced locally and systemically in response to P. gingivalis in different strains of mice, suggesting a degree of genetic control over the response to P. gingivalis.

The influence of genetic variation on the splenic T cell cytokine and specific serum antibody responses to Porphyromonas gingivalis in mice.

BACKGROUND: T cell cytokine profiles in the spleens and anti-Porphyromonas gingivalis antibodies in the sera of P. gingivalis-immunized BALB/c (H-2d), CBA/CaH (H-2k), C57BL6 (H-2b), and DBA/2J (H-2d, C5 deficient) mice were examined. METHODS: Mice were immunized either by intraperitoneal injections of P. gingivalis outer membrane antigens and Freund's incomplete adjuvant weekly for 3 weeks or sham-immunized with PBS and adjuvant, followed by subcutaneous challenge with live organisms 1 week after the final immunization. Spleens were excised and blood samples collected by heart puncture at 0 and 7 days after challenge. Splenic CD4 and CD8 cells were stained for intracytoplasmic interleukin (IL)-4, interferon (IF)-gamma, and IL-10 and levels of anti-P. gingivalis antibodies in the serum samples determined by ELISA. RESULTS: Lesion sizes in immunized BALB/c mice remained stable for the 7-day experimental period. Immunized CBA/CaH and C57BL6 mice exhibited large lesions at day 1 reducing by day 7 particularly in the latter strain. Lesions in immunized DBA/2J mice were still larger than the other strains at day 7. With the exception of DBA/2J mice, sham-immunized mice demonstrated lesions which did not show signs of healing by day 7. T cell cytokine responses in sham-immunized mice at day 0 were low, increasing to a variable degree by day 7 after challenge in the 4 strains. Immunized BALB/c mice demonstrated intermediate T cell responses while generally exhibiting a stronger IFN-gamma response than IL-4 or IL-10. Immunized CBA/CaH and C57BL6 mice showed weak T cell cytokine responses while immunized DBA/2J displayed the strongest T cell responses particularly in regard to IL-4 positive cells. Sham-immunized mice had low levels of serum anti-P. gingivalis antibody levels at day 0 with levels increasing significantly by day 7 after challenge. Antibody levels in immunized mice seemed to correlate with lesion sizes. Immunized C57BL6 mice had the highest antibody levels followed by CBA/CaH, BALB/c with DBA/2J exhibiting low levels. The T cell and B cell antibody responses in each strain appeared to exhibit an inverse relationship. CONCLUSIONS: This study has shown that genetic differences at the level of H-2 haplotype induce variations in the local and T and B cell responses to P. gingivalis antigens. The responses of DBA/2J mice which have the same haplotype as BALB/c mice suggest that factors other than H-2 haplotype such as the C5 deficiency may influence this immune response. The significance of the specific antibody and T cell responses and of their inverse relationship to susceptibility to periodontal disease remains to be determined.

Cytokine profiles of lesional and splenic T cells in Porphyromonas gingivalis infection in a murine model.

T cell cytokine profiles in the spleens and Porphyromonas gingivalis-induced lesions of P. gingivalis-immunized mice were examined. BALB/c mice were immunized with P. gingivalis outer membrane (OM) antigens/mouse weekly for 3 weeks followed by challenge with live organisms 2 weeks after the final immunization. Control mice were immunized with PBS. Spleens were excised at 0 and 4 days and lesions at 1, 4, and 7 days after challenge. Splenic and lesional CD4 and CD8 cells were stained for intracytoplasmic interleukin (IL)-4, interferon (IFN)-gamma, and IL-10. More than 50% of the T cells in the spleens of immunized mice were IFN-gamma positive at day 0 which was significantly higher than for IL-4 or IL-10, these levels decreasing significantly 4 days after challenge. Less than 6% of the T cells in sham immunized mice were cytokine positive at day 0, although at day 4, there was a significant increase in the percent IL-10 positive CD4 cells and IL-4 and IL-10 positive CD8 cells. There were no differences in the percent IL-4, IFN-gamma, or IL-10 positive T cells in the lesions of immunized mice, but there was a dramatic decrease at day 7 to very low levels in control mice. In conclusion, the results of the present study show a predominant Th1 response in the spleens of BALB/c mice after immunization with P. gingivalis OM antigens, suggesting that a protective immune response to P. gingivalis may involve a strong IFN-gamma response.

Induction of the CD1a Langerhans cell marker on human monocytes.

Monocytes have recently been recognized as a precursor of Langerhans cells. This study examined the regulatory influence of the epithelial environment on the putative first step of the transition towards a Langerhans cell phenotype--the induction of CD1a antigen. The keratinocyte-derived cytokines granulocyte-macrophage-colony-stimulating factor, tumour necrosis factor-alpha, interleukin-6, and interleukin-1 beta induced CD1a expression, as did supernatants of keratinocytes extracted from inflammatory sites (periodontitis). Induction was abrogated by transforming growth factor-beta and a keratinocyte-derived interleukin-1 inhibitor. The optimal temperature for induction was 34 degrees C, not 37 degrees C. These results demonstrate that the components of the epithelial environment (cytokines and lower temperature) exert important influences, which may be part of local regulation of Langerhans cell development.

The effect of vitamin A on the proliferation of oral epithelium in the rat.

This study assessed the effect of topical and systemic 13-cis-retinoic acid on rat palatal epithelial proliferation with bromodeoxyuridine labelling and silver stained nucleolar organizer regions. Sixty male Wistar rats were assigned randomly to a control group or treatment groups of topical orabase, RA in orabase, 5 times/week or twice weekly systemic doses of 12 mg RA in coconut oil. The rats were treated for 1, 2, 4 or 8 weeks and killed 1 h post-injection of 40 mg/kg BrdUrd. The palatal mucosae were processed, using immunoperoxidase staining or silver stain to visualize BrdUrd utilization or AgNORs, respectively. The number of BrdUrd positive nuclei/mm overlying epithelium and number and area of AgNORs in the basal cells were assessed using image analysis. ANOVA indicated there was no significant effect of treatment on LN/mm or the numbers or areas of AgNORs. The LN/mm for the 8 w group (29.5) was significantly lower than the other groups. RA did not influence rat palatal epithelial proliferation, but across all groups increased age was associated with decreased proliferation. It would appear that the proliferation of normal oral mucosa may not be subject to altered proliferation when treated with therapeutic doses of topical or systemic RA.