Evaluation of an outreach education model over five years: Perception of dental students and their outreach clinical mentors

INTRODUCTION

The objective was to investigate changes in students' and clinical mentors' perceptions of a model for outreach education over a 5-year period, 2006-2010.

MATERIAL AND METHOD

Two cohorts of last-year students of a dental problem-based curriculum and their clinical mentors in the Public Dental Service (PDS) were invited to respond to a questionnaire. In 2006, 85% of 54 students and 72% of their 54 mentors responded; 98% of 40 students and 88% of 41 of the mentors did so in 2010. Participants scored their level of agreement with different statements on a numeric rating scale and gave comments.

RESULTS

Dental students and their clinical mentors reported that they shared a consistent and favourable perception of this outreach education model over 5 years. The students reported increased professional confidence and self-reliance. Clinical mentors expressed a transfer of knowledge to their clinics. Differences in scoring were seen between students and mentors for two statements in 2006 and two statements in 2010 (P < 0.05).

CONCLUSIONS

The current model for outreach education received favourable and stable ratings over the 5-year period. This model resulted in that students perceived that they became self-reliant, which may facilitate their transition from being a student to becoming a professional. The current model supports exchange and professional development for students, faculty and outreach clinics. This leads us to look at outreach education as an opportunity to form a mutual learning community comprised of the outreach clinics and the dental school.

Oral Pilocarpine for Treatment of Opioid-induced Oral Dryness in Healthy Adults

Pilocarpine induces a profuse flow of saliva when administered orally, but effects on drug-induced oral dryness have not been examined. The aim of this trial was to investigate if pilocarpine increases production of saliva in individuals suffering from dry mouth due to treatment with opioids. Sixty-five individuals were enrolled in a randomized, double-blind, placebo-controlled trial. The subjects received tramadol (50 mg t.d.s.) to induce oral dryness, and were thereafter assigned to one of three groups. Secretion rate of saliva was measured before and after tramadol, and after the oral administration of pilocarpine (5 mg), placebo, or no treatment. Baseline characteristics did not differ among the groups (mean ± SEM: 0.37 ± 0.06 mL/min), and tramadol lowered the secretion at the same level in all groups (0.15 ± 0.02 mL/min). Pilocarpine increased the flow above that observed with placebo (0.66 ± 0.19 vs. 0.15 ± 0.02 mL/min). Thus, pilocarpine re-establishes the flow of saliva in the state of tramadol-induced oral dryness.

Presence of Lactobacillus reuteri in saliva coincide with higher salivary IgA in young adults after intake of probiotic lozenges

The aim of this study was to compare the concentration of salivary immunoglobulin A (IgA) and the selected interleukins (IL)-1β, IL-6, IL-8 and IL-10 in young individuals with presence and non-presence of Lactobacillus reuteri in saliva after a three-week intervention with probiotic lozenges. The study group consisted of 47 healthy individuals aged 18-32 years with no clinical signs of oral inflammation. In a randomised, double-blind, placebo-controlled, cross-over trial participants ingested two lozenges per day containing two strains of the probiotic bacterium L. reuteri or placebo lozenges. The intervention and wash-out periods were three weeks. Stimulated and unstimulated whole saliva was collected at baseline and immediately after termination of the intervention periods. The samples were analysed for total protein, salivary IgA and selected cytokines. In this extended analysis, data were collected by analysing baseline and follow-up saliva samples related to ingestion of the probiotic lozenges for the presence of L. reuteri through DNA-extraction, PCR-amplification and gel-electrophoresis. At baseline, 27% of the individuals displayed presence of L. reuteri and 42% were positive immediately after the three-week probiotic intervention. Individuals with presence of L. reuteri in saliva had significantly higher (P<0.05) concentrations of salivary IgA and %IgA/protein at the termination of the probiotic intake compared with non-presence. No differences in the cytokine levels were observed. In conclusion, detectable levels of L. reuteri in saliva coincided with higher concentrations of salivary IgA and %IgA/protein in stimulated whole saliva after the three-week daily intake of probiotic lozenges. Our findings suggest that monitoring the presence of probiotic candidates in the oral environment is important to interpret and understand their possible immune-modulating role in maintaining oral health.

The Legacy of Cariologist Douglas Bratthall, an Inspired Scientist

Douglas Bratthall was an inspirational cariologist known for his playful curiosity, thoughtful inquisitiveness, incisive scholarship, and energetic leadership. He became a time, mind, and global traveler who viewed his career path as an exotic safari. This ‘Discovery!’ report identifies where his era’s burning issues have led and how they were shaped by his contributions.

Proceedings for the 5th Asia-Pacific Conference on Disaster Medicine: Creating an Agenda for Action

Disaster medicine has come to the forefront and has become the focus of interest not only in the medical community, but also in the eyes of the public. The 5th APCDM was convened in Vancouver, Canada, 27–30 September 2000. It brought together over 300 delegates from 32 countries to share their experiences and thoughts regarding disaster events and how to effectively manage them.

The conference was devoted to the task of establishing priorities and creating an Agenda for Action. From the discussions, key actions required were defined:

Communications: (1) Identify existing regional telehealth groups and gather lessons to be learned from them; (2) Form a telehealth advisory group to work with regional groups to compile telehealth initiatives, identify international protocols in telehealth already in existence, and solicit feedback before setting international standards; and (3) Increase corporate partnerships in the fields of telehealth and telecommunications, and invite corporations to send delegates to future APCDM meetings. This should be an initiative of the APCDM, the World Association of Disaster and Emergency Medicine (WADEM), or the European Society of Emergency Medicine.

Education and research: (1) Formalize education in disaster medicine and management. The World Health Organization and WADEM should take a leadership role; (2) WADEM is requested to hold a conference with a focus on qualitative research; (3) WHO is requested to continue the provision of international research teams, but to advocate for the development of national disaster research infrastructure; (4) Make research findings and reports available on web sites of such organizations as WHO and PAHO; (5) Develop the translation of research for community utilization. The WHO and PAHO are organizations that are requested to consider this action; and (6) WADEM/APCDM are requested to focus future conferences on applied research.

Information and data: (1) Create an “Information and Data Clearinghouse on Disaster Management” to collect, collate, and disseminate information; (2) Collect data using standardized tools, such as CAR or Hazmat indices; (3) Analyze incentives and disincentives for disaster readiness and establish mechanisms for addressing the obstacles to preparedness; and (4) WADEM is requested to develop a web site providing a resource list of interdisciplinary institutions and response activities, organized by country, topic, and research interests. Links to other pertinent web sites should be provided.

Interdisciplinary development: (1) Focus on the interdisciplinary nature of disaster response through more conferences encompassing grassroots efforts and through WADEM publications; (2)Develop and apply a standardized template of Needs Assessment for use by multidisciplinary teams. Team Needs Assessment is essential to determine the following: (a) Local response and international assistance required; (b) Appropriate command system; and (c) Psychosocial impact and support necessary.

Psychosocial aspects: (1) Incorporate relief for caregivers into action plans. This should include prime family members who also are caregivers; and (2) Implement measures that give survivors control over the recovery process.

Response management. (1) Define relationships and roles between governments, military and security personnel, non-governmental organizations (NGOs), and civic groups. Use an international legal framework and liability to reinforce accountability of disaster responders; (2) Establish a more sophisticated use of the media during disasters; (3) Establish standards in key areas. WADEM is requested to write “White Papers” on standards for the following areas: (a) management, (b) health/public health, (c) education/training, (d) psychosocial, and (e) disaster plans; (4) Establish task forces to anticipate and resolve issues around evolving and emerging disasters (e.g., chemical and biological terrorism, landmines, emerging infectious diseases). WADEM was again identified as the vehicle for promoting this action.

The responsibility of the next meeting of the Asia-Pacific Conference on Disaster Medicine will be to measure progress made in these areas by assessing how well these collective decisions have been implemented.

Attitudes of some European dental undergraduate students to the placement of direct restorative materials in posterior teeth

The aim of this article was to report on the attitudes, opinions and confidences of final year dental students in three European schools towards the restoration of posterior teeth and in particular towards the use of amalgam and resin composite. One hundred and twenty-eight pre-piloted questionnaires were distributed to final year dental students in Cardiff, Dublin and Malmö. The questionnaire sought information relating to various opinions and attitudes towards the use of amalgam and resin composite in posterior teeth. Information was returned anonymously. Ninety-one completed questionnaires were returned (response rate=71%; Cardiff: n =40, Dublin: n=24, Malmö: n=27). Ninety-three per cent of Malmö students (n=24), 67% of Dublin students (n=16) and 60% of Cardiff students (n=24) reported that they feel confident when placing posterior resin composites. One hundred per cent of Malmö students (n=27), 75% of Cardiff students (n=30) and 33% of Dublin students (n=8) would prefer to have a resin composite rather than amalgam, placed in one of their own posterior teeth. Eighty-five per cent of Malmö students (n=23), 30% of Cardiff students (n=12) and 25% of Dublin students (n=6) perceive amalgam as being harmful to the environment. For the restoration of a posterior tooth in a pregnant female, 44% of students (n=40) would place a resin composite restoration, and 7% (n=6) would place an amalgam restoration, while 32% (n=29) would place a temporary restoration. Students at Malmö report that they place more posterior resin composites and have greater confidence at placing posterior resin composites than students at Cardiff or Dublin. There was confusion relating to the choice of restorative materials for pregnant females. Large variations in restorative strategies among graduates must be considered as dental professionals can practice in all countries within the European Union.

Tramadol-induced oral dryness and pilocarpine treatment: effects on total protein and IgA

Pilocarpine induces a profuse flow of saliva, and it may re-establish saliva production in cases of drug-induced oral dryness. The aim of the study (a sub-study to the previous trial investigating the pilocarpine fluid effects in individuals suffering from drug-induced dry mouth) was to search for saliva quality changes induced by the treatments. Sixty-five individuals were enrolled in a randomized, double-blind, placebo-controlled trial. The subjects received tramadol to induce oral dryness. Secretion rate was measured before and after tramadol, and then after pilocarpine, placebo, or no treatment. All saliva was analyzed for its protein and IgA content in the pilocarpine (n=15) and placebo groups (n=12). At baseline, the flow of saliva was 0.47±0.05ml/min, the protein output 0.17±0.2mg/min and the IgA output 0.022±0.002mg/min. After tramadol treatment (50mg 3×/day over two days), the flow was reduced by 64%, protein output by 52% and the IgA output by 38%. While placebo treatment did not affect any of the variables, the flow was 120%, the protein output 193% and the IgA output 83% of the baseline characteristics after pilocarpine treatment (5mg). Thus, the pilocarpine-induced increase in the flow rate in the state of tramadol-induced oral dryness results in saliva with a well preserved protein concentration but with a decrease in IgA concentration. However, compared to baseline, there was neither a decrease in output nor in concentration of IgA.

Attitudes of final-year dental students to bleaching of vital and non-vital teeth in Cardiff, Cork, and Malmö

The aim of this study was to determine attitudes of final-year dental students in Cardiff, Cork and Malmö towards tooth whitening. Following receipt of ethical approval, pre-piloted questionnaires were distributed to final-year dental students in Cork, Cardiff, and Malmö as close as possible to graduation. The questionnaire sought information relating to various opinions and attitudes towards the use of bleaching techniques including safety of bleaching, confidence in the provision of bleaching, recommendations to patients, teaching received, awareness of restrictions on the use of bleaching products and management of simulated clinical scenarios. Eighty three per cent (n = 116) of questionnaires were returned. Cork dental students had the most didactic teaching (2-h vital, 1-h non-vital bleaching) compared to Cardiff or Malmö students (0 h each). More Cork students regarded bleaching as safe (76%, n = 28) than Cardiff (70%, n = 32) or Malmö (36%, n = 12) students. More than 50% of Cork students feel they know enough about bleaching to provide it in practice, significantly more than Cardiff (< 25%) or Malmö (< 25%) students. The majority of students would provide vital bleaching after qualification (100% (n = 37) Cork; 82% (n = 27) Malmö; 76% (n = 35) Cardiff). In simulated clinical scenarios, more Cork students would propose bleaching treatments (89%n = 33) than Malmö (64%n = 21) or Cardiff (48%n= 22) students. Variations exist in the attitudes and approaches of three European dental schools towards bleaching. Dental students need to be best prepared to meet the needs of their future patients.

In Vitro Fluoride Release and the Antibacterial Effect of Glass Ionomers Containing Chlorhexidine Gluconate

Modification of inherent fluoride-containing materials with chlorhexidine provides an antibacterial and remineralizing varnish with potential anti-cariogenic properties.

Low salivary IgA activity to cell-surface antigens of mutans streptococci related to HLA-DRB1*04

BACKGROUND/AIMS

Mutans streptococci are found in almost all individuals, though there are large differences in colonization levels between individuals. These differences are not readily explained, though several factors are believed to influence the colonization. One factor is the immune response to mutans streptococci, mainly provided by salivary immunoglobulin A (IgA). In a previous study, differences in salivary IgA reactions to oral streptococci were observed between human leukocyte antigen (HLA)-DR4-positive and DR4-negative individuals. A lower salivary IgA activity to Streptococcus mutans in particular was most pronounced for two DR4 subgroups, DRB1*0401 and *0404. The main purpose of this study was to further investigate, in a larger study group, the salivary IgA activity to antigens of three oral streptococci in relation to different HLA-DRB1*04 alleles.

METHODS

Stimulated saliva was collected from 58 HLA-DRB1*04-positive individuals. Whole cell antigen extracts from S. mutans, Streptococcus sobrinus and Streptococcus parasanguis and the streptococcal antigen (SA) I/II were separated in SDS-PAGE, transblotted and detected with diluted saliva (Western blot), and analyzed in a computer program. All distinct immunoblot bands over 100 kDa were recorded and compared in relation to DRB1*04.

RESULTS

The immunoblots revealed lower salivary IgA reactions to S. mutans, S. sobrinus and SA I/II, but not to S. parasanguis, for the DRB1*0401- and *0404-positive individuals compared to other DRB1*04 types. For the *0401 subgroup there was a significant association with a lower IgA response to S. mutans.

CONCLUSION

The results confirm earlier observations and may also support previous demonstrated association between colonization by mutans streptococci and the serologically defined HLA-DR4.

Platelet storage solution improves the in vitro function of preserved platelet concentrate

BACKGROUND AND OBJECTIVES

Stored platelets develop biochemical lesions, manifest as depressed haemostatic function, clot retraction and wound healing. ViaCyte trade mark, a proprietary experimental preservative solution (comprising D-ribose, D-glucose, Hanks solution, Hepes solution, bovine serum albumin, tic anticoagulant peptide and sterile water), was tested in comparison with the presently accepted storage solution, citrate-dextrose-phosphate-plasma (CDP-P), to evaluate its ability to preserve platelet function during storage.

MATERIALS AND METHODS

Platelets stored in ViaCyte and platelets suspended in CDP-P were transferred to polypropylene tubes with PL732 covers and analysed for adenine nucleotide levels (ATP molecules), in vitro agonist-mediated P-selectin expression and aggregation.

RESULTS

After 5 days of storage at room temperature, 12.2% of platelets stored in ViaCyte exhibited P-selectin expression at rest, and 64.2% exhibited P-selectin expression upon activation with thrombin challenge, an increase of 52%. Platelets stored in CDP-P exhibited 44.4% P-selectin expression at rest, suggesting significant activation during storage, and thrombin stimulation resulted in P-selectin expression of 47.9%, an increase of only 2.5% (P< or =0.002, untreated vs. treated). ViaCyte also maintained ATP levels throughout the storage period, while these levels became depressed in platelets stored in CDP-P (P< or =0.02, untreated vs. treated). Storing platelets in the experimental preservative solution maintained their ability to aggregate, while control platelets lost their ability to aggregate in response to agonist.

CONCLUSIONS

ViaCyte appears to protect platelets during storage, reflected by a low level of induced lesions. Platelets stored in ViaCyte maintain energy levels at their resting state, which preserves their ability to aggregate and secrete granule contents, and ensures the availability of additional platelets for activation upon in vitro challenge.

Salivary IgA reactions to cell-surface antigens of oral streptococci

BACKGROUND

In the immunoblot technique, using whole bacteria cell extracts as antigens, both intra- and extracellular antigens are detected, which gives a large number of immunoglobulin A (IgA) reactions (immunoblot bands) when incubated with saliva. It is important to distinguish which immunoblot bands represent bacterial cell-surface antigens, since these antigens could be involved in adhesion mechanisms and be available for blocking in vivo.

METHODS

Bacterial extracts of Streptococcus mutans, Streptococcus sobrinus, Streptococcus parasanguis and the streptococcal antigen I/II were separated using SDS-PAGE. The antigens were detected with saliva in Western blot. Untreated saliva and saliva in which cell-surface reactive IgA had been absorbed with whole bacteria cells were analyzed.

RESULTS

Approximately half the number of the bands were absent for saliva absorbed with homologous cells, compared to untreated saliva. The absorption pattern was almost identical for S. mutans and S. sobrinus but not for S. parasanguis. Salivary IgA reactive against streptococcal antigen I/II was absorbed by S. mutans cells, to a lesser extent by S. sobrinus cells, and not at all by S. parasanguis cells.

CONCLUSION

It is likely that the bands that were absent after absorption represented cell-surface antigens. For S. mutans and S. sobrinus, these bands were probably the streptococcal antigen I/II.

HLA-DR4 and salivary immunoglobulin A reactions to oral streptococci

The aim of this study was to describe and compare salivary immunoglobulin A (IgA) antibody reactions to extracts of strains of three oral streptococci in human leukocyte antigen (HLA)-DR4-positive and -DR4-negative subjects. Whole paraffin-stimulated saliva samples were collected from 27 apparently healthy subjects. Previous HLA typing showed that 20 subjects were DR4 positive and 7 were DR4 negative. HLA-DRB1*04 subtyping was performed among the DR4-positive subjects. Whole-cell antigen extracts from Streptococcus mutans (KPSK 2), Streptococcus sobrinus (OMZ 65) and Streptococcus parasanguis (Nt 62) were separated in SDS-PAGE. The antigens were immunoblotted with diluted saliva (Western blot), scanned and analyzed in a computer system. All immunoblot bands were recorded in DR4-positive and DR4-negative saliva pools, and bands with an optical density >or=0.1 were selected for analysis in individual salivas. The DR4-negative subjects in general had more immunoblot bands and more distinct bands than did the DR4-positive subjects. A higher concentration of total IgA in saliva was correlated with more bands, especially to antigens separated from S. mutans. When the number of bands was calculated per IgA unit, significant differences were observed between DR4-positive and DR4-negative salivas. This was particularly seen for S. mutans and S. parasanguis. As the number of bands was analyzed in relation to DR4 subgroups, DRB1*04, there was a lower salivary IgA activity to S. mutans in the DRB1*0401 and *0404. The variable level of correlation previously demonstrated for S. mutans colonisation and serologically defined DR4 positive subjects might be explained by the heterogeneity in this group, and the relation should be sought on a subgroup level.

The comparison of the efficacy and safety of intravenous versus subcutaneous immunoglobulin replacement therapy

To compare the efficacy of immunoglobulin replacement therapy given intravenously versus subcutaneously to prevent infections in patients with primary antibody deficiency syndromes, an international, multicenter, open label, crossover study was designed. Forty patients were randomized to receive either subcutaneous or intravenous immunoglobulin replacement therapy for 1 year. In the second year, patients were switched to the alternative treatment, enabling patients to act as their own controls. Equivalent doses were given by both routes. Ethical approval was obtained from the review boards of the hospitals in which the patients were seen and written consent obtained from each patient. Patients with a primary antibody deficiency syndrome, either common variable immunodeficiency or IgG subclass deficiency or specific antibody deficiency, who required immunoglobulin replacement therapy were included in the study. Patients were excluded if they had significant thrombocytopenia (defined as platelets less than 50 x 10(9)/liter), had high levels of anti-IgA antibodies (defined as greater than 1:8192), or had severe adverse reactions to a blood product within the last 2 years. The primary end point was the number of infections and their severity (moderate and major) during the two treatment periods. Secondary end points were adverse reactions, length of infections, days lost from school or work due to infections, and acceptability of treatment regimens to the patients. Based on the assumption that it was difficult to prove equivalence of therapies statistically in crossover studies, an arbitrary number of 40 patients was selected on the basis that this might be achievable in 2 years. There are no significant differences in efficacy or adverse reaction rates between immunoglobulin replacement therapy given subcutaneously or intravenously.

Transient reduction of mutans streptococci on tooth surfaces using a chlorhexidine-containing glass ionomer cement varnish

Chlorhexidine (CHX) has been incorporated in polymer-based varnishes to reduce mutans streptococci (ms) by the sustained release of CHX. Such varnishes often adhere well to teeth initially but are easily peeled off. To be effective, repeated application is necessary. Glass ionomer (GI) cements interacts with tooth minerals to form a stronger bond, and the inherent brittleness of the cement makes it difficult to remove in large fragments. The fluoride content may also reduce demineralisation. The aim of this study was to observe whether ms could be reduced interproximally and in saliva by a single application of a GI cement containing 3.3% CHX gluconate (CHX-GI). After professional tooth cleaning and a mouth rinse for 2 min with 0.2% CHX, the teeth of six subjects were coated with CHX-GI cement. An additional six subjects were treated with a GI cement that did not contain CHX, and seven subjects received professional tooth cleaning only. Ms samples were taken interproximally with the tooth pick method before and after treatment. Interproximal levels were classified according to the number of colony-forming units (c.f.u.) found: 0, 1-20, 21-100, and > 100. Saliva ms were sampled with the Strip Mutans method. After four weeks, the interproximal levels of ms had decreased only in the CHX-GI group (p < 0.05). In this group 9 of 14 highly colonised sites (> 100 c.f.u.) remained reduced throughout this period. In the GI and the untreated group a slight increase of ms interproximally was seen after one week. The interproximal ms scores in all groups approached baseline levels after 8 weeks. There were no significant differences in saliva ms levels between the groups during the test period. GI cement may be a possible vehicle for CHX in reducing ms interproximally.

Clinical evaluation of efficacy and safety of a new method for chemo-mechanical removal of caries. A multi-centre study

The aim of the study was to evaluate the clinical efficacy and safety of a new method (Carisolvtrade mark) for chemo-mechanical removal of caries. At four centres, 137 consecutive patients (64 females and 73 males aged 3-85 years, mean 35) entered a prospective, controlled, randomised open study. One primary caries lesion with distinct dentine involvement was selected per patient. A total of 116 lesions in permanent and 21 in deciduous teeth were selected. Caries was removed with traditional drilling or the new method. Gel was applied onto the carious dentine and the softened caries gently removed with specially designed hand instruments. New gel was applied and the procedure was repeated until no more debris could be removed and the surface was hard as judged by clinical criteria (probing and visual inspection). An independent examiner judged the cavity being caries-free or not, using clinical criteria. One hundred and thirteen patients were randomised for gel treatment and 24 for drilling. Three patients selected for drilling did not complete the treatment. Total caries removal was achieved in 106 cases with gel and in 19 with drilling. The reasons for incomplete caries removal were step-by-step excavation in 5 cases, unsuccessful caries removal in 1 case for each treatment, while 2 cases refused inspection. Mean (+/- SD) time for caries removal was 10.4 (+/-6.1) min with the gel method and 4.4 (+/-2.2) min with drilling. Mean volume of gel used was 0.4 (+/-0.2) ml. Eighty-two of 107 patients perceived that the new method caused less discomfort compared to drilling. Dentine caries was effectively removed using the Carisolv method without any adverse reactions.

Fissure penetration and antibacterial effect in vitro of a glass ionomer cement containing chlorhexidine gluconate

Chlorhexidine has been incorporated in different varnishes to provide a slow release system on the tooth surface in order to reduce mutans streptococci. To provide an alternative vehicle for chlorhexidine with better adhesion properties compared to resin-based varnishes, glass ionomer cement (GI) has been suggested. However, one disadvantage for glass ionomers is a longer setting time compared to the resin-based varnishes. The aim with this study was to compare the fissure penetration and antibacterial characteristics of a glass-ionomer cement (GI) with a GI containing chlorhexidine gluconate (GI-CHX), and GI-CHX with added tataric acid (GI-CHX-TA) to reduce its setting time. Antibacterial properties against mutans streptococci were assessed by agar diffusion. GI, GI-CHX and GI-CHX-TA were applied with a microbrush on the occlusal surfaces of 4, 4 and 6 extracted molars respectively. After setting of cements, sections were ground with 1 mm intervals and photographed. The fissure penetration and adaptation of the cements were scored excellent, acceptable or unacceptable under blind conditions according to a standard. Seventy percent scored excellent with GI-CHX-TA (n = 54) compared with 40% with GI-CHX (n = 48) and 38% with GI (n = 40), (p < 0.05). GI-CHX and GI-CHX-TA had significant better antibacterial properties compared to GI or GI with added tataric acid only.

HLA-DR4 and number of mutans streptococci in saliva among dental students and staff

Our aim was to corroborate previous findings that HLA-DR4 carriers are characterized by higher levels of mutans streptococci in saliva than are individuals expressing other HLA-DR types. Of 68 subjects (dental students, staff, and faculty) who were sampled for salivary counts of mutants streptococci, 13 subjects with the lowest counts of mutans streptococci and 15 subjects with the highest counts were selected for HLA-typing. Of the 13 who expressed HLA-DR4, 8 were heavily colonized by mutants streptococci. Although a trend towards a relationship was found between HLA-DR4 carriage and high levels of mutans streptococci, it was not statistically significant. In this selected population, knowledge of how to minimize the risk of caries and mutans streptococci level may have influenced the results.

Clinical guidelines and self-assessment in dental education

This paper describes an educational programme where clinical guidelines are used in dental education and assesses the value of these guidelines as perceived by undergraduate students. It presents a comparison of students' own assessments of their performance with those of their instructors, according to such guidelines. The educational programme at the Faculty of Odontology, Lund University, is described through 3 main principles: problem-based learning, adoption of a holistic attitude to patient care and the promotion of oral health. The dental curriculum occupies 5 years comprising 10 semesters. 41, 5th semester students (16 male and 25 female) participated in the study. Students were introduced to guidelines in group discussions at the beginning of the semester. At the completion of a patient's planned course of treatment, the outcome was formally assessed both by students and clinical instructors. Performance was scored in various categories as "excellent", "acceptable" or "unacceptable" according to the standards defined. A total of 1373 scores were made by both students and instructors. 88% cent of students used the guidelines often or almost always and found them useful. Overall, no students received an "unacceptable" score and 40% of students achieved a score of "excellent". Female students tended towards a higher score, but this was not significant. Instructors' and students' scores agreed in almost 90% of instances. Students under-scored their performance more frequently than they over-scored it. It appears that the use of clinical guidelines may encourage an increased awareness of the decision-making processes involved in clinical practice, but it must be acknowledged that these guidelines are complex both in derivation and application.

Gating of thrombin in platelet aggregates by pO2-linked lowering of extracellular Ca2+ concentration

Platelet accretion at sites of vascular injury yields a neo-tissue comprising packed platelets and having an interstitial space not supplied with blood. Within growing thrombi platelet masses become anoxic and depolarize to yield interstitial cation concentrations characteristic of the more voluminous platelet cytosol, with extracellular [Ca2+] falling below that adequate to support the plasma clotting system. The platelet-associated clotting system reactivates during disaggregation of the thrombi in vitro, which proceeds with high yield of apparently basal, functional platelets when specific anticoagulants are included in the disaggregating media. The capacity of regulatory demand to lower extracellular [Ca2+] in the microenvironment of platelet aggregates provides a physiological basis for evolution of the highly cooperative calcium interactions of the hemostasis system.

Lifelong treatment with gammaglobulin for primary antibody deficiencies: the patients' experiences of subcutaneous self-infusions and home therapy

Primary antibody deficiencies are chronic conditions and the patients usually need lifelong replacement therapy with gammaglobulin to prevent or reduce infections. It has been shown that the gammaglobulin can be given safely as subcutaneous infusions, instead of intramuscular injections or intravenous infusions. The major aim of this multi-centre study was to investigate the perceptions of the subcutaneous method among patients using it, both in hospital settings and as self-infusions at home. The study included 152 patients: 89 women, 63 men, mean age 44 years (range 18-76). Data were collected by using questionnaires. The patients were found to have a strongly positive attitude towards receiving the replacement therapy as subcutaneous infusions, perceived the method as effective in preventing infections and wished to retain the treatment. However, the younger patients found the subcutaneous infusions more uncomfortable and were less determined to continue with the therapy as compared with the older individuals. The responsibility for self-infusions at home was accepted by the patients, leading to an increased independence from the health care personnel and to a feeling of flexibility and freedom. As these patients have a chronic disease and are in need of lifelong treatment, it is important to discuss the development of structured education and training programmes in which special emphasis is placed on the support of the younger patients. It is suggested that Orem's nursing model of self-care may serve as a conceptual framework for nurses working in this specific area of nursing care.

Subcutaneous immunoglobulin replacement in patients with primary antibody deficiencies: safety and costs

Immunoglobulins (IgG) as replacement therapy in primary antibody deficiencies can be given as intramuscular injections, or as intravenous or subcutaneous infusions. Our aims were to obtain information on the frequency of adverse systemic reactions during subcutaneous therapy, the occurrence and intensity of tissue reactions at the infusion sites, and serum IgG changes. Furthermore, we compared costs between the different replacement regimes. Our study included 165 patients (69 women, 96 men, aged 13-76 years) with primary hypogammaglobulinaemia or IgG-subclass deficiencies. Data were compiled from questionnaires filled in by the patients and from their medical records. 33,168 subcutaneous infusions (27,030 in home therapy) had been given. 106 (of which 16 were at home) adverse systemic reactions (100 mild, 6 moderate) were recorded in 28 patients (17%). No severe or anaphylactoid reactions occurred. Despite large immunoglobulin volumes given during 434 patient years (28,480 infusions), no signs have been found that indicate the transmission of hepatitis virus. Transient tissue reactions occurred at the infusion sites but were not troublesome to most patients and we found significant increases in mean serum IgG. The use of subcutaneous instead of intravenous infusions at home would reduce the yearly cost per patient for the health-care sector by US $10,100 in Sweden alone. We conclude that subcutaneous administration of IgG is a safe and convenient method of providing immunoglobulins. We were able to reach serum IgG concentrations similar to those by the intravenous therapy and we found that the method could also be used successfully in patients with previous severe or anaphylactoid reactions to intramuscular injections.

Reduction of cusp deflection resulting from composite polymerization shrinkage, using a light-transmitting cone

For investigation of whether the use of a transparent plastic cone (Light-tip) influenced cusp deflection, as compared with a conventional method (control), the following experiments were performed. Mesiodistocclusal (MOD) cavities were prepared in 10 extracted premolars, and stainless steel pins were placed on the cusps. The cavities were bonded with Scotchbond Multipurpose, and the distance between the pins was measured. Control restorations using P-50 were placed in three increments, each increment having been polymerized for 40 s. For placing the test restorations, the Light-tip was fitted to the end of the curing wand and pressed into the resin in the proximal box, and the curing light was turned on. The next increment filled the recess created after the removal of the cone in the resin, and curing was performed with the plastic cone in the occlusal box. The third increment was cured without the cone. Each tooth was used for four restorations. In 16 of 20 cases, a significantly decreased cuspal flexure was found when the cone was used. The flexure decreased 24%, as compared with control.

Intestinal and circulating antibody-forming cells in IgA-deficient individuals after oral cholera vaccination

In search for a possible explanation for the different susceptibility to mucosal infections in IgA-deficient (IgAd) individuals, the frequency of total immunoglobulin-secreting cells (ISC) and vaccine-specific antibody-secreting cells (ASC) in intestinal mucosa and peripheral blood was determined by the enzyme-linked immunospot (ELISPOT) assay before and after peroral vaccination with a B subunit-whole cell cholera vaccine. Two groups of IgAd individuals, frequently infected and non-infected respectively, and normal controls were studied. Before cholera vaccination there were significantly higher frequencies of total IgM and IgG ISC in the gut, but not in the blood, in the IgAd individuals than in the controls. However, there were no significant differences between healthy and infection-prone IgAd individuals in this respect. In response to oral cholera vaccination, intestinal cholera toxin (CT)-specific IgG and IgM ASC were significantly more abundant among the IgAd individuals with a history of frequent infections than among the healthy IgAd individuals and controls. A similar difference in IgG and IgM ASC, although not significant, was also noted in blood. In IgAd individuals with frequent infections the vaccine induced variable anti-CT IgM ASC responses in the gut, ranging from no increase to a few strikingly high responses. In the controls, the CT-specific responses were dominated by IgA ASC. The data show that oral cholera vaccination evoked strong CT-specific IgG ASC responses, and in some cases also strong IgM ASC responses in the intestinal mucosa of IgAd patients with a history of frequent infections. The healthy IgAd individuals unexpectedly responded with lower numbers of CT-specific IgG ASC and did not show any increase of CT-specific IgM ASC in the intestinal mucosa. Thus, inability to mount a mucosal immune response to an oral antigen cannot in itself explain recurrent infections among many IgAd individuals.

Increase of in vitro curing depth of class II composite resin restorations

Simulated class II cavity preparations were made in black Plexiglas acrylic, and various posterior composite resins were placed in the preparations and cured with and without a transparent cone-shaped "Light-tip" device. The transparent Light-tip device improved the curing depth approximately 2.2 mm, and this ability to illuminate the deeper portions of the restoration increases the potential to improve the curing of composite resin.

Influence of transient salivary flora on assessment of mutans streptococci level by the "Strip mutans" method

The Dentocult SM ("Strip mutans") method occasionally shows decoloration of broth and of colonies of mutans streptococci on the plastic strip, thereby making interpretation difficult. In an attempt to explain the phenomenon and to investigate the influence of the salivary flora on the "Strip mutans" method, a total of 46 subjects were sampled. Saliva was analyzed using the "Strip mutans" method and conventional plating techniques to identify mutans streptococci, enterococci, staphylococci, enteric bacteria, and yeasts. Approximately 85% of the "Strip mutans" scores coincided with the conventional MSB-plating method. Two samples showed decolored mutans streptococci colonies on the "Strip mutans" strip. Enterococcus spp. were present in the saliva of these test subjects and could grow in the "Strip mutans" broth. Enterococcus faecalis was able to induce the same type of decoloration under experimental pure culture conditions. Three "Strip mutans" samples showed small colonies of mutans streptococci, visible only under magnification (x 10-20). Staphylococcus epidermidis was present in these saliva samples and showed heavy growth in the broth. Under experimental pure culture conditions S. epidermidis also inhibited the growth of mutans streptococci to some extent.

In vitro antibacterial effect of chlorhexidine added to glass-ionomer cements

The aims of the present study were to investigate the antibacterial properties of glass-ionomer cements containing different concentrations of chlorhexidine and the possible release of chlorhexidine from the compound. Chlorhexidine gluconate or diacetate was mixed with glass-ionomer cements and tested in vitro against strains of Lactobacillus casei and mutans streptococci. A spectrophotometric test was used to monitor the release of chlorhexidine from the mixture. In a broth culture test, the higher the concentrations of chlorhexidine in the mixture, the longer the time of antibacterial effect on Streptococcus mutans and the greater the tendency of the material to deteriorate. Agar diffusion tests revealed bacterial inhibition in a dose-response manner. The tested bacterial strains were similarly inhibited and the antibacterial properties decreased with time. A minor portion of added chlorhexidine was released from the cement. The deterioration of the cements indicates that the material could be useful as a varnish-like chlorhexidine carrier.

Human leukocyte antigens in relation to colonization by mutans streptococci in the oral cavity

Mutans streptococci are well established as caries-inducing microorganisms in man. Most humans carry the bacteria, but in highly different numbers. This cannot be explained by environmental factors only. The aim of this study was to investigate a possible association between levels of colonization by mutans streptococci and the presence of certain B and DR human leukocyte antigens (HLA). Altogether, 170 subjects who had their HLA antigens determined (76 renal transplant patients and 94 healthy blood donors) were selected for the investigation. Paraffin-stimulated saliva samples were taken using the wooden spatula method with subsequent cultivation of mutans streptococci on mitis salivarius bacitracin agar plates. An association between the absence of HLA-DR 4 antigens and low, or undetectable, levels of mutans streptococci was found. This was statistically significant for the immunosuppressed renal transplant subjects. The same trend was observed among the healthy blood donors.

Reduction of cervical gaps in class II composite resin restorations

Class II cavities prepared in brass models and in extracted teeth were restored with three light-cured composite resins. A transparent cone-shaped device (Light-tip) at the end of the light source was pressed into the filling material in the proximal box for curing the resin. A second layer was filled in the recess left by the cone and cured without the cone. Controls consisted of fillings cured in two layers. In the brass cavities the contraction gap was 10 microns (+/- 10.6) with use of the cone compared with 109.5 microns (+/- 46.5) in control fillings (p less than 0.001). Extracted teeth were restored without etching of the enamel. Cervical contraction gaps in control restorations were reduced by more than half with the use of the transparent cone technique.

Simplified method to estimate salivary buffer capacity

A new and simplified method to estimate the salivary buffer capacity was tested. The method, Dentobuff Strip, consists of a pH indicator paper that has been impregnated with acid. A small volume of saliva is added to the strip and after 5 min the color of the strip is compared with a chart. The colors have been chosen to indicate low, medium, or good buffer capacity. The buffer capacity of stimulated saliva samples from 62 subjects was measured with the new method and compared with two commonly used clinical methods, Dentobuff, and an electrometric method. The three methods correlated well, and patients with a low salivary buffer capacity (final pH less than or equal to 4), according to the electrometric method, were readily identified with the new Dentobuff Strip method.

N-acetylcysteine added to saliva does not affect IgA concentration or the agglutination of Streptococcus mutans in vitro

N-acetylcysteine (NAC) or placebo were mixed with parotid or whole saliva to a final concentration of 0.004-10 mg/ml saliva. Placebo and NAC-containing parotid saliva had the same bacterial agglutinating capacity for 4 strains of Streptococcus mutans. Immunoglobulin A (IgA) concentration in whole saliva, using ELISA and single radial immunodiffusion assays, did not reveal any differences between NAC and placebo-treated samples. NAC did not affect the immunoelectrophoretic pattern of IgA.

Labeling of binding sites for beta 2-microglobulin (beta 2m) on nonfibrillar surface structures of mutans streptococci by immunogold and beta 2m-gold electron microscopy

As little detail is known about the surface structure of streptococci in the mutans group and the relationship of surface structure to host ligand-binding functions, the twofold purpose of this investigation was to examine in detail, by a range of electron microscopic techniques, the surface structures of streptococci in the different species of the mutans group and to investigate the distribution of beta 2-microglobulin (beta 2m)-binding sites on such structures. Strains representing Streptococcus mutans, S. cricetus, S. rattus, S. sobrinus, and four fresh isolates were studied by shadowcasting and histochemical staining of whole-mounted cells as well as by ultrathin and thick sectioning of embedded specimens. beta 2m-binding site distribution was visualized by indirect immunogold electron microscopy and by direct bacterial binding of beta 2m-conjugated gold probes. Shadowcast preparations revealed binding of gold probes to the cell surface of known beta 2m-binding strains but not to their polar fibrillar appendages. These long fibrils, common to all strains, were trypsin and sonication sensitive and stained with lead citrate but not with uranyl acetate or ruthenium red. More gold particles were bound by the indirect technique. For grid-mounted bacteria, the gold was mostly bound in clusters at the periphery of the cells. When gold probes were reacted in suspension with bacteria before mounting onto grids, a more even distribution of the gold was seen, but the bacteria were aggregated. Heating the bacteria eliminated beta 2m-gold binding but had no effect on the morphology of the fibrils. Thick sections of embedded bacteria prereacted with beta 2m-conjugated gold probes were analyzed by stereo imaging. A wispy, uranyl acetate-stained fuzzy layer, distinct from the fibrils seen by shadowcasting and extending up to one cell diameter from the cell wall, contained the gold probes. These findings introduce a concept that binding sites for some salivary ligands on mutans streptococci may be clustered on very delicate, nonfibrillar structures extending much further from the cell wall than previously appreciated. As for beta 2m, which composes part of the human histocompatibility antigens, part of the bacterial surface would be coated at a distance from its body with a protein not necessarily recognized as foreign by the host.

Antimicrobial action of new, proprietary lining cements

The antibacterial activity of innovative, commercial lining cements was investigated. A liner which contains calcium hydroxide and is polymerized by visible light (Prisma VLC Dycal) and a glass-ionomer lining cement (GC lining cement) were compared with two more established lining cements (Advanced Formula II Dycal and Life). Antibacterial activity and hemolysis-like agar change at 24, 48, and 72 hours were measured on blood agar plates inoculated with Streptococcus mutans KPSK 2 (serotype c), Lactobacillus casei ssp rhamnosus ATCC 11981, and chewing-stimulated saliva. Prisma VLC Dycal did not affect bacteria or agar. The glass-ionomer lining cement, with an acidic pH at setting, had the most pronounced effect on all test organisms and on the agar. Even after 48 hours' setting, it inhibited growth of S. mutans. The control lining cement (AFII Dycal) showed antibacterial activity toward both specific micro-organisms as well as some activity against the salivary organisms. The material Life showed only partial inhibition of microbial growth. For all lining cements, the hemolytic-like agar change correlated with antibacterial effects. The surface pH of the freshly-set cements containing calcium hydroxide was alkaline. It would seem that a simple correlation between high surface pH and antibacterial activity among these cements does not exist. Also, further biological characterization of new lining cements is required to direct their appropriate clinical use.

Absorption of fibronectin from human saliva by strains of oral streptococci

Freshly collected human submandibular/sublingual saliva contained between 1.0 and 26.1 micrograms/ml of fibronectin as determined by ELISA. 10(9) organism of 12 oral streptococcal strains tested removed between 2.6 and 89.4% of the fibronectin present in 400 microliters saliva. Fibronectin was retained in bacterial pellets after washings in buffer but could be eluted using 1 M NaCl.

Salivary interactions with homologous and heterologous strains of oral streptococci and epithelial cells

Twenty strains of oral streptococci resembling the species of Streptococcus mitior and Streptococcus salivarius were isolated from four subjects and were incubated with homologous and heterologous whole clarified saliva. Supernatants of bacterially absorbed and control saliva were analyzed in tandem crossed immunoelectrophoresis (TCIE) against a rabbit anti-human saliva antiserum. Six to eight antigens were detected. After incubation with the bacteria, the saliva supernatants showed a decrease in the number of antigens detectable by TCIE. For all four salivas tested, the homologous group of strains absorbed fewer antigens. Some of the antigens could be eluted from bacterial pellets with 1 M NaCl after repeated washings in PBS. Epithelial cells also absorbed fewer antigens from homologous than heterologous saliva.

Agglutination of Streptococcus mutans by low-molecular-weight salivary components: effect of beta 2-microglobulin

Radiolabeled monomeric human beta 2-microglobulin (beta 2m) was tested for binding to Streptococcus mutans strains in buffers containing 1 mM calcium (Ca2+). Binding was seen to strains with a previously established binding capacity of aggregated beta 2m. Monomeric beta 2m agglutinated beta 2m-binding strains when Ca2+ was present. At Ca2+ concentrations of 1.4 mM, 0.032 micrograms of monomeric beta 2m per ml caused bacterial agglutination. Parotid saliva was gel filtered on a Sephadex G-75 column, and low-molecular-weight fractions containing beta 2m could agglutinate S. mutans cells. Five of six strains that could bind beta 2m were agglutinated by these fractions, but only one of five nonbinding strains was. All strains tested were agglutinated by void volume fractions. A new method for the measurement of turbidity in bacterial agglutination inhibition experiments with parotid saliva was used. Suspensions containing parotid saliva, bacteria, and control serum were directly compared in a spectrophotometer with test suspensions containing goat anti-human beta 2m, bacteria, and saliva. Thus, the spectrophotometer directly read the difference in agglutination of the two suspensions, and the result was presented as one curve by the recorder. Agglutination of five beta 2m-binding strains of S. mutans was inhibited or decreased by the addition of goat anti-human beta 2m as compared with control serum. The agglutination of two beta 2m-nonbinding strains and one with variable binding was not inhibited. Thus, salivary beta 2m may contribute to agglutination of S. mutans cells in parotid saliva.

beta 2-Microglobulin in saliva and its relation to flow rate in different glands in man

The concentration of beta 2-microglobulin (beta 2-m) in parotid saliva and sera from 13 adult hypogammaglobulinaemic subjects and in parotid saliva from 7 normal adults was determined by radioimmunoassay. Parotid and submandibular/sublingual saliva was collected from four normal and one hypogammaglobulinaemic subject in unstimulated and stimulated samples, and concentrations of IgA and beta 2-m were determined. The beta 2-m concentration in parotid saliva from hypogammaglobulinaemic subjects was 0.50 mg/l (0.2-1.1) and in normal adults 0.41 mg/l (0.2-0.9). In parotid saliva, the concentration of beta 2-m was negatively correlated with the flow rate, whereas in submandibular/sublingual a positive correlation was seen. Serum levels of beta 2-m in hypogammaglobulinaemic subjects were within the normal range of healthy adults. Gel filtration of saliva separated beta 2-m from IgA and from high molecular weight agglutinins. Beta 2-m was eluted as one single peak.

Further characteristics of beta2-microglobulin binding to oral streptococci

A total of 85 strains of oral bacteria representing Streptococcus mutans, S. sanguis, S. Mitior, S. salivarious, S. milleri, S. infrequens, S. durans, S. lactis, S. faecalis, S. faecium, S. equinus, Streptococcus species group E, Actinomyces, and one group A Streptococcus were tested for binding of aggregated human beta 2-microglobulin. Positive affinity between bacteria and aggregated human beta 2-microglobulin was detected in 36% of the strains. No apparent correlation with bacterial species, serotype, or group was noted. No positive strains were detected among seven group I:A S. sanguis strains (P < 0.01). Binding constants for one S. mutans strain indicated heterogeneous binding structures on the bacterial surface. The number of binding sites for aggregates of human beta 2-microglobulin involving multipoint attachment varied from 70 to 1,700 per bacterial cell. With whole saliva as buffer, a general increase in affinity was seen. Variations in salt concentrations of the buffers revealed different salt-dependent species-associated uptake patterns. Oral bacteria tended to have an uptake maximum at a salt concentration similar to that seen in saliva. Binding structures for aggregated beta 2-microglobulin on oral streptococci were sensitive to pepsin, heat, and formaldehyde treatment. Bacterial binding structures for aggregated beta 2-microglobulin might represent one of several factors of importance for bacterial attachment in the oral cavity. Experimental conditions reflecting the salivary milieu increased the degree of interaction, emphasizing the importance of physiological test systems for such studies.

A new technique for restraint of mice

One hundred ninety-five mice were restrained for an ear punching and toe clipping identification procedure using a new technique. The unique feature of the restraint method was that the mouse's head was immobilized within a finger loop of surgical scissors.

Interactions between human serum proteins and oral streptococci reveal occurrence of receptors for aggregated beta 2-microglobulin

A total of 31 strains of oral streptococci representing Streptococcus mutans, Streptococcus sanguis, Streptococcus mitior, Streptococcus salivarius, and Streptococcus milleri were tested for possible binding of human immunoglobulins G, G1, G2, G3, G4, A1, A2, M1, and M2 and haptoglobin, hemoglobin, fibrinogen, and aggregated beta 2-microglobulin. Radiolabeled beta 2-microglobulin in aggregated form showed affinity for 20 of the 31 strains tested. Binding activity for the protein was found in strains belonging to all five species. The bacterial receptor was resistant to trypsin. Monomeric, unlabeled beta 2-microglobulin did not interfere with the binding of the aggregated form. Of the other proteins tested, only the immunoglobulin A1 protein showed positive binding, and that was only with a single strain of S. milleri. beta 2-Microglobulin is present on all nucleated cell membranes in vivo. The reaction between aggregated beta 2-microglobulin and oral streptococci is a new type of human-bacterium interaction which should be considered in studies of bacterial adherence.