The role of the randomised controlled trial in restorative dentistry and the correct purpose of observational data.

It has been argued that the randomised controlled trial design is unsuitable for restorative dentistry and that cohort studies or the analysis of large observational datasets without randomisation is more suitable. This opinion article examines why randomisation in clinical trials is needed and why big observational data is not enough for clinical inference.

High-viscosity glass-ionomer cements for direct posterior tooth restorations in permanent teeth: The evidence in brief.

OBJECTIVES: To provide a brief overview of the current evidence-base for direct posterior tooth restorations in permanent teeth placed using high-viscosity glass-ionomer cement (HVGIC). METHODS: The evidence sources: laboratory trials, uncontrolled clinical trials, controlled clinical trials with HVGIC restorations placed after conventional cavity preparation by drill and controlled clinical trials with HVGIC restorations placed following the atraumatic restorative treatment (ART) approach, were assessed based on systematic reviews and meta-analyses, as well as methodological studies. RESULTS: The precision and validity of evidence from laboratory trials, uncontrolled clinical trials and non-ART controlled clinical trials are insufficient for clinical guidance. Clinical evidence for HVGIC restorations placed using ART, comprises of 38 controlled clinical trials including over 10 000 tooth restorations. Systematic review results of these trials indicate no statistically significant differences (p>0.05) in the failure rates between HVGIC and amalgam restorations in single- and multiple surface tooth cavities after up to six years. Although, many of these trials suffered from too low sample sizes, their results could be pooled in three meta-analyses. The bias risk in all trials was judged to be high. CONCLUSION: Controlled clinical trials with HVGIC restorations placed using ART provide the bulk of the available evidence that suggest that the failure rate of direct posterior HVGIC restorations in permanent teeth are comparable to that of dental amalgam restorations.

Chlorhexidine for the prevention of alveolar osteitis.

This systematic review assessed the efficacy of chlorhexidine for the prevention of alveolar osteitis and occurrence of adverse reactions. Databases were searched until 20 April 2011. Trial inclusion criteria were: titles/abstracts relevant to topic; prospective 2-arm (or more) clinical study design. Trial exclusion criteria were: not all entered subjects accounted for; subjects of both groups not followed up the same way; lack of computable data; chlorhexidine not the primary test agent; duplication of data; outcome of interest other than incidence of alveolar osteitis. Individual datasets were extracted from accepted articles. Bias risk in trials was assessed. 10 of 13 included trials were accepted. From these, 16 dichotomous datasets were extracted. Two of six application protocols favoured chlorhexidine over placebo: Single application of 0.2% chlorhexidine gel placed in the socket immediately after extraction versus placebo gel (RR 0.40; 95% CI: 0.18-0.90; p=0.03) and 0.12% chlorhexidine rinse applied on day of surgery and used twice daily for 7 days postoperatively versus placebo rinse (RR 0.50; 95% CI: 0.27-0.93; p=0.03). These results are negated due to high bias risk. Chlorhexidine did not cause higher adverse reactions than placebo. Further high-quality randomised control trials are needed.

Failure rate of high-viscosity GIC based ART compared with that of conventional amalgam restorations--evidence from an update of a systematic review.

INTRODUCTION: Atraumatic Restorative Treatment (ART) involves using only hand instruments for removing carious tooth tissue and then restoring the resulting cavity with an adhesive restorative material. OBJECTIVE: To answer the question as to whether, in patients with carious cavities of any class in primary and permanent teeth, ART restorations with high-viscosity glass-ionomer cement (GIC) have a higher failure rate than amalgam restorations placed after drilling, in tooth cavities of the same size, dentition and follow-up period. METHODS: Thirteen databases were searched for relevant trials up to January 2012. Hand-searching was performed for non indexed journals. References of included trials were checked. Prospective, clinical controlled trials with a followup period of at least one year were selected. The investi gated outcome was restoration failure. Meta-analysis was conducted and internal trial validity was assessed in-depth. RESULTS: Twenty trials were accepted for review. The majority of the results show no differences between the types of intervention. The current evidence indicates that the failure rate of high-viscosity GIG/ART restorations is not higher than, but is similar to that of conventional amalgam fillings after periods longer than six years. There is a risk that these results are affected by bias and confirmation by further trials is recommended.

Therapeutic effect of glass-ionomers: an overview of evidence.

The requirements for an ideal restorative material include adhesion to tooth structure (enamel and dentine) and an ability to withstand the traumas of occlusion. However, some level of an anticaries effect is also desirable. After a long history of glass-ionomer cement (GIC) development, an evidence base in support of the therapeutic effect of GIC, particularly with regard to its anticaries effect, is emerging. This evidence is increasingly presented through systematic reviews of clinical GIC application and, to a certain extent, relates to a caries-preventive effect of the material itself. However, the strength of evidence supporting other aspects of GIC, such as a higher remineralizing effect, fluoride uptake in hard tooth tissue and fluoride release of GIC, is limited. Nevertheless, the results of these in situ and laboratory trials provide valuable insights into factors that facilitate understanding of the clinical efficacy of GIC.

Caries-preventive effect of resin-modified glass-ionomer cement (RM-GIC) versus composite resin: a quantitative systematic review.

AIM: To determine whether resin-modified glass-ionomer cement (RM-GIC), when compared with composite resins (CR), offers a significant caries-preventive effect. STUDY DESIGN: Quantitative systematic review. METHODS: Five databases were searched until 29 July 2010. Inclusion criteria were: relevant to review question related to orthodontic or restorative treatment; published in English; prospective clinical 2-arm study. Exclusion criteria were: no computable data reported; study groups not followed up in the same way. References of included articles were checked. The outcome measure was absence of carious lesions. Dichotomous datasets for both groups were extracted from accepted trials. Trials were assessed for selection-, detection/performance, attrition and publication bias. RESULTS: Of the 11 trials included, 6 were accepted and 24 datasets extracted; 17 datasets showed no difference after 4 weeks to >25 months. There were 7 datasets that favoured (p < 0.05) RM-GIC after 12 - 24 months. The results are limited by risk of selection-, detection-/performance bias and attrition bias. Risk of publication bias was identified. CONCLUSIONS: The overall results showed either no difference between the materials, or indicated that RM-GIC has a superior caries-preventive effect. The clinical meaning of this result remains uncertain due to risk of bias. High-quality randomised control trials are needed in order to answer the review question conclusively.

Salt fluoridation: a meta-analysis of its efficacy for caries prevention.

UNLABELLED: The aim of this meta-analysis was to assess the caries preventive effect of Salt fluoridation (SF) in the permanent dentition in children. THE OBJECTIVES WERE TO COMPARE: (1) the caries preventive effects of SF versus no exposure in different age cohorts (6-8; 9-12; and 13-15 years old); (2) SF versus other community based interventions (milk or water fluoridation [WF]). METHODS: 9 English and 2 non-English databases were searched for papers that reported on the caries preventive effect of groups (with controls) that were exposed to SF in the form of mean DMFT scores with standard deviations. Differences in exposed and nonexposed groups were computed on the basis of weighted mean differences (WMDs) with 95% confidence intervals (CIs). RESULTS: For 6-8 year olds, the pooled reduction in DMFT scores was -0.98 [95% CI: -1.68 to -0.29]; for 9-12 year olds, it was -2.13 [95% CI: -2.55 to -1.70] and for the 13-15 year old groups, -4.22 [95% CI: -6.84 to -1.55]. All the analyses favoured the SF groups (p <0.001). For SF versus WF, there was no difference (-0.11 reduction [95% CI: -0.29 to +0.07]). CONCLUSION: Within limitations, the pooled estimates of the WMDs for the different age cohorts favoured SF versus no exposure.

Resin-modified glass-ionomer cements versus resin-based materials as fissure sealants: a meta-analysis of clinical trials.

AIM: To appraise quantitatively current evidence regarding the caries-preventing effect of resin-modified glass-ionomer cement (RM-GIC) fissure sealants in comparison to that of resin-based fissure sealants. STUDY DESIGN: Systematic review with meta-analysis. METHODS: 8 Anglophone databases and 2 Lusophone databases were searched until 15 April 2009, using a pre-determined search strategy. Clinical trials were considered for inclusion if their titles/abstracts were relevant to the topic, published in English, Portuguese or Spanish and had a two-arm longitudinal study design. The outcome measure of the caries-preventive effect was caries absence on sealed teeth. Two reviewers independently extracted data from the accepted articles in order to complete a 2x2 table for meta-analysis. The unit of interest was the tooth, and the number of caries-free teeth (n) at the end of each time interval (6, 12 and 24 months) was compared against the total number of evaluated teeth (N). STATISTICS: Datasets were assessed for their clinical and methodological heterogeneity, following Cochrane guidelines, and only homogeneous datasets were combined for meta-analysis, using a random effects model (RevMan 4.2). Differences in the caries-preventive effect were computed on the basis of the combined Relative Risk (RR) with 95% confidence interval (CI). RESULTS: Of the 212 articles identified, only 6 trials were included. From these, 19 separate datasets were extracted. For the pooled data, equivalent caries-preventive effects were observed at 6 months (RR= 0.98, 95% CI 0.95- 1.00; p = 0.08); 12 months (RR=1.00, 95% CI 0.96-1.04, p = 0.99) and 24 months (RR=1.01, 95% CI 0.84-1.21, p = 0.91). The 36-month data (not pooled) favoured resin-based sealants (RR 0.93, 95% CI 0.88-0.97, p = 0.002). CONCLUSIONS: This meta-analysis found no conclusive evidence that either material was superior to the other in preventing dental caries.

Absence of carious lesions at margins of glass-ionomer and amalgam restorations: a meta- analysis.

AIM: To report on the absence of carious lesions at margins of glass ionomer cement (GIC) and amalgam restorations. METHODS: Six Anglophone and 1 Lusophone databases were searched for articles up to 5 January 2008. Inclusion criteria for articles were: (i) titles/abstracts relevant to topic; (ii) published in English, Portuguese or Spanish language; (iii) reporting on a randomised control trial. Exclusion criteria were: (i) insufficient random allocation of study subjects (ii) operator and subject not blinded, where appropriate; (iii) not all entered subjects accounted for at trial conclusion; (iv) subjects of both groups not followed up the same way. Articles were accepted only if they complied with all the criteria. Ten articles complied with the inclusion criteria and were selected for review. From these 4 were rejected and 6 articles reporting on 8 separate studies accepted. Due to aspects of heterogeneity, studies were sub-grouped before meta- analysis. RESULTS: Significantly less carious lesions were observed on single-surface GIC restorations in permanent teeth after 6 years as compared to restorations with amalgam (OR 2.64 - CI 95% 1.39 - 5.03, p= 0.003). No studies investigating multiple-surface restorations on permanent teeth were identified. Studies investigating carious lesions at margins of restorations in primary teeth showed no difference between both materials after 3 and 8 years. CONCLUSIONS: Carious lesions at margins of single-surface GIC restorations are less common than with amalgam fillings after 6 years in permanent teeth. No difference was observed in primary teeth. More trials are needed in order to confirm these results.

Oral health service systems in Gauteng Province, South Africa.

OBJECTIVES: To describe the provision of restorative care and dental operators' opinion about their conditions of service in a South African provincial oral health service system. DESIGN: Assessment of oral health service over a four-month period. SETTING: Gauteng Province, South Africa. SUBJECTS: Dental operators in public oral health service. INTERVENTIONS: Operator interview, collection of treatment statistics, calculation of the mean score of restoration-extraction ratio per operator. MAIN OUTCOME MEASURES: Number and type of restorations and tooth extractions rendered, daily patient load, perceived occupational stress level and opinion about main reasons for operator stress. RESULTS: A total of 88,705 patients had been treated. The mean number of patients treated daily was 26 (SD = 8.4). Operators extracted 39,242 teeth and placed 2992 restorations. The main type of dental treatment was extraction. The mean score of the restoration-extraction ratio per operator was 0.09 in the primary, and 0.07 in the permanent dentition. The mean level of stress was 4.9 (SD = 1.9). The majority of operators regarded patients' high dental anxiety as the main reason for stress, followed by high patient load. The mean level of stress increased with the increase in number of patients treated per day (r = 0.44, p = 0.004) and also with the increase in the number of tooth extractions performed per day (r = 0.41, p = 0.008). CONCLUSIONS: Restorative dental care in this public oral health service is limited, tooth extraction being the predominant treatment provided. High patient load and high patient levels of dental anxiety determine this situation, according to the operators. The health authority should introduce appropriate solutions in order to address the prevailing situation adequately.

Antibacterial effect of chlorhexidine- containing glass ionomer cement in vivo: a pilot study.

This in vivo pilot study was carried out to test the antibacterial effect of glass ionomer containing chlorhexidine (test group) in comparison to conventional glass ionomer (control group). Fifty 6- to 11-year-old children with one occlusal lesion in a molar were randomly allocated to test and control groups in a parallel-group design. The cavity walls and one half of the floor were cleaned and restored with one of the materials without dentine conditioning. The restorations were removed after 7 days. Dentine samples were taken from the cleaned (affected dentine) and noncleaned area (infected dentine) at baseline and at day 7. Samples were anaerobically and aerobically cultivated for mutans streptococci, lactobacilli and total viable bacterial count (TVC) following common laboratory procedures. ANCOVA was used to test for treatment effects. Seven days after treatment, a significant decrease in anaerobic and aerobic bacterial counts (p = 0.0001) was shown. Lower numbers of anaerobic lactobacilli (p = 0.02), TVC (p = 0.008) and aerobic lactobacilli and TVC (p = 0.03), but not of mutans streptococci, were indicated in the test group compared to the control group. A significant reduction in aerobic lactobacilli from infected dentine treated with the glass ionomer containing chlorhexidine (p = 0.05) was observed whereas in affected dentine, anaerobic mutans streptococci, lactobacilli and TVC and aerobic TVC and mutans streptococci were significantly lower in the test group 7 days after treatment (p = 0.01). We conclude that the present pilot study revealed lower microorganism counts in chlorhexidine-containing glass ionomers than in conventional glass ionomers for both affected and infected dentine over a 7-day period.

Waviness of atraumatic restorative treatment (ART) prepared surfaces.

INTRODUCTION: The wave (W) element offers a surface topography assessment method with the potential to yield unique data. AIMS AND OBJECTIVES: This study uses glass ionomer cement specimens prepared with six Atraumatic Restorative Treatment (ART) surface treatments to explore arc- and line-modified waviness of these surfaces to determine if they gave similar results. METHODS: Six specimens (5 x 1.5mm) were prepared for each of the six surface treatments: (1) surface compressed with a Vaseline lubricated finger (Va); (2) Va followed by carving with an excavator(Ca); (3) Ca burnished with a ball burnisher (Bu); (4) surface compressed with the gloved finger lubricated with poly-acrylic acid (Aa); (5) surface cured against a Mylar strip (My); (6) My polished with a white rubber sulcus wheel (Po). After storage in distilled water for seven days at 37 degrees C W(a), W(v), W(p), W(t) was analysed using arc- and line-modifications of the raw profile. The data were analysed using a General Linear Models analysis and Tukey's Studentised range test with P < 0.05. RESULTS: Ca and Bu; Va and Aa; and My and Po formed three groups with descending ranking order for W whether arc- or line-modified. Arc-modified tracing data was unable to statistically distinguish between surface treatments whereas line-modification showed significant differences between treatments for all parameters measured (W(a), W(v0, W(p), W(t)). CONCLUSIONS: Line-modified waviness data was better able to distinguish between surface treatments than arc-modification. Wave offers unique surface topography data having potential value to dental materials researchers.

Measurement of dental restorative material topography.

INTRODUCTION: The tracing of peaks and valleys produced during surface profiling of dental materials are read against a mean line which can be modified in the form of a line or arc. Roughness (R) is commonly used to measure the topography of restorative materials, but the profile (P) value is also generated during the tracing and includes both roughness and waviness of the surface. AIMS AND OBJECTIVES: The purpose of this study was to determine if line and arc modified tracings and R and P surface topography measurements give similar results. METHODS: Thirty six cavities (5 x 1.5mm) were prepared in Perspex discs, restored with Fuji IX, a high strength glass ionomer cement, following the Atraumatic Restorative Treatment (ART) technique and the surface of six cavities were each treated as follows: press finger with vaseline (Va); press finger with polyacrylic acid (Aa); carving (Ca); burnishing (Bu); Mylar strip (My); polishing (Po). Topography was assessed using a profilometer which ran three equidistant tracings (3.6mm) on each surface giving a total of 18 readings for each treatment (n=6). The results of Ra, Rv, Rp, R, and Pa, Pv, Pp, P, for all 6 surface treatments were compared and analysed using ANOVA and Tukey's studentised range test with significance set at P<0.05. RESULTS: Within R + line, R + arc, P + line and P + arc, significant differences were apparent between treatments. Pairwise comparisons showed fewer instances of significant differences between surface treatments when R + line (1 instance of significant difference) was compared to R + arc (2). P + line showed 12 instances of significant differences between surface treatments while P + arc showed no difference. CONCLUSION: Both line and arc tracings gave similar results for R and either may be used in assessing surface roughness. The total deviation of the profile P showed more significant differences between treatments with line than with arc and may be a more sensitive tool when dealing with small sample numbers or subtle differences between surface treatments.

Minimal intervention dentistry (MI) for South Africa.

The intention of Minimal Intervention Dentistry (MI) is to preserve as much tooth tissue as possible and to offer less threatening care to fearful patients. MI is based on a new understanding of cariology and the therapeutic value of biomimetic materials such as Glass lonomers. It has particular relevance to a new caries classification and employs treatment concepts such as selective caries removal and sealed restorations. The MI approach is appropriate for the vast majority of the population in South Africa; it addresses the public fear of dental treatment. It can be an effective private practice builder and is thus applicable to private and public services.

Undergraduate training in the atraumatic restorative treatment (ART) approach--an activity report.

The Division of Public Oral Health at the University of the Witwatersrand conducted a 2-week ART training course for 5th year dental students in the School of Oral Health Sciences. Students were taught both theoretical knowledge and clinical skills in ART. Course evaluation showed that the course achieved its aims and objectives and was considered a worthwhile experience by students. However, there were some limitations to the format of the programme. We recommend that ART should be integrated as part of clinical student training in the BDS curriculum.

Microscope observations of ART excavated cavities and restorations.

This in vitro light and scanning electron microscope study examined 39 extracted tooth specimens, hand excavated and restored according to atraumatic restorative treatment (ART), using 'press finger', by 'skilled' and 'novice' operators. Surface features of five excavated cavities, 12 restoration surfaces and the tooth restoration relationships of 22 bisected restored tooth crowns were examined to better understand the clinical effect of the technique. Hand-excavated cavity surfaces were rough with a complex surface arrangement of grooves, crevices, ridges, furrows and overhangs. Enamel and dentine were covered with debris except where surface fractures exposed enamel prisms and occluded dentinal tubules. Ten of the 22 bisected restored specimens had large voids (1-3 mm in length) within the glass-ionomer cement (GIC) restoration or at the tooth-restoration interface. Smaller bubbles (< 50 microns) and irregular shaped inclusions were common in all restorations. Adaptation of the GIC to the cavity margin was extremely variable and easily distinguished from the effects of dehydration shrinkage. It is thought that cavity surface irregularities could cause placement problems making it difficult to adapt the GIC to cavity peripheries. While 'press finger' enabled excellent penetration of GIC into fissures, the technique left restoration surfaces rough. At low magnification, surfaces were irregular; at magnifications higher than X500 scratches, pits, porosities, chipping and voids were evident. However, the 'press finger' technique was able to merge the GIC to a fine edge on the occlusal surface so that the restoration margin was not obvious. No apparent difference was found between the restorations placed by the 'skilled' and 'novice' operators. Tooth-restoration relationships in the ART approach are entirely different to those of traditional restorative techniques. The ART approach requires skill, diligence and comprehension to be undertaken correctly.