Social gradient in caries experience of Belgian adults 2010.

OBJECTIVE: This study aims to explore the caries experience of the Belgian population in relation to social indicators. BASIC RESEARCH DESIGN: Data collection (2009-2010) consisted of an oral health questionnaire and examination during a home visit. PARTICIPANTS: Representative sample of the Belgian population (⟩5 years old). Only the economically active population was included for final analyses. MAIN OUTCOME MEASURES: ANOVA and multivariable regression analyses were used to reveal associations between social indicators, oral hygiene, untreated decay, DMFT and edentulousness. RESULTS: 2742 participants completed the questionnaire, of whom 2563 were examined clinically. Most (53%) were female and mean age was 43.3 years (95% CI= 41.2-45.4). In the total population, 11.1 % were caries-free (DMFT = 0) and mean DMFT was 10.8 (95% CI = 10.0-11.5). In the analysed subsample, higher educated participants had lower DMFT scores than those with low or no educational qualifications (p = 0.003). Employment status was associated with the presence of untreated tooth decay, especially in the youngest age group (p = 0.015), and with edentulousness (p = 0.02), with a higher risk among unemployed women of being completely edentulous (OR = 5.32; 95% CI = 1.75-16.12). Untreated tooth decay was related to frequency of tooth brushing and plaque index (p ⟨ 0.002 and ⟨ 0.001 respectively). CONCLUSIONS: Caries experience in Belgium, expressed as mean DMFT and proportion of untreated tooth decay, is more associated with level of education and employment status than with family income, which is still the main criterion for larger government allowances for healthcare in Belgium.

Efficacy of three different pulpotomy agents in primary molars: a randomized control trial.

AIM: To compare the clinical and radiographic efficacy of Biodentine™ , ProRoot® White Mineral Trioxide Aggregate (WMTA) and Tempophore™ as pulpotomy medicaments in the treatment of carious primary molars. METHODOLOGY: A parallel-design, randomized controlled trial was developed. Patients above 3 years of age with carious primary teeth with vital pulps without spontaneous pain or history of swelling were included. Fifty-eight patients (82 teeth) with a mean age of 4.79 ± 1.23 years were included. The teeth were randomized, blinded and allocated to one of the three groups (Biodentine™ , ProRoot® WMTA or Tempophore™ ) for pulpotomy treatment. All teeth were followed up clinically and radiographically (after 6, 12 and 18 months) by two blinded calibrated investigators. A generalized estimating equation (GEE), Wald chi-square test and an intention-to-treat analysis (ITT) with 'last carried forward' approach were performed using Statistical Package for Social Sciences v 21.0 (IBM Corp., Armonk, NK, USA). RESULTS: Forty-six patients and 69 teeth were available for follow-up after 18 months. Clinical success (radiographic success in parenthesis) was 95.24% (94.4%), 100% (90.9%) and 95.65% (82.4%) in the Biodentine™ , ProRoot® WMTA and Tempophore™ groups, respectively, but the difference was not significant. Pulp canal obliteration was significantly different amongst the experimental groups as the Biodentine™ group exhibited significantly more pulp canal obliteration when compared to the ProRoot® WMTA group at 6 months (P = 0.008) and 18 months (P = 0.003). CONCLUSIONS: After 18-month follow-up, there was no significant difference between Biodentine™ in comparison with ProRoot® WMTA or Tempophore™ .

Validation of the Oral Survey-B System for Electronic Data Capture in National Oral Health Surveys.

The aims of the present study were to incorporate and to validate the electronic capture of participant-related outcomes into the Oral Survey-B System, which was originally developed for the electronic capture of clinical data. The validation process compared the performances of electronic and handwritten data captures. The hypothesis of noninferiority would be established if participants performed electronic data capture of the questionnaire survey with an effectiveness of at least 95% of that of handwritten data capture. In this multicenter, randomized, one-period crossover study design, participants (n = 261) were allocated to start with either electronic or handwritten data capture. The incorporation of the electronic self-completed questionnaire into the Oral Survey-B System was successful. The validation of the electronic questionnaire was performed by participants aged from 18 to 75 years. The interrater reliability of participants performing electronic and handwritten data capture of nonclinical assessments per questionnaire and per entry showed a kappa value of 0.72 (95% CI: 0.53-0.94). The noninferiority of electronic data capture in relation to that of the handwritten data capture and transfer was shown (p < 0.0001; 95% CI: 1.47-2.99). In conclusion, the electronic capture of participant-related outcomes with the Oral Survey-B System, originally designed for capture of clinical data, was validated. The electronic data capture was accurate and limited the number of errors. The participants were able to perform electronic data capture effectively, supporting its implementation in further National Oral Health Surveys. With the consideration of participant preference and time savings, this could lead to the implementation of electronic data capture worldwide in National Oral Health Surveys.

Comparison of occlusal caries detection using the ICDAS criteria on extracted teeth or their photographs.

BACKGROUND: Using photographs of occlusal surfaces instead of extracted teeth for the detection of caries can be useful in multicenter studies or education. Using a panel of observers, ICDAS scores on teeth or photographs were evaluated against the histological gold standard. The hypothesis was that both outcomes were equivalent. METHODS: Four examiners with different experience in ICDAS scored photographs of occlusal surfaces of 100 extracted teeth on a monitor using ICDAS criteria. Two of the examiners had previously scored extracted teeth prior to photography. Digital images of histological sections of the teeth were observed by all examiners and consensus scores were given for each investigation site (gold standard). Kappa statistics and Spearman correlation coefficients as well as repeated measure ANOVA were performed. ROC curves were constructed for each examiner and the areas under the ROC-curves (AUC) of both scoring techniques (extracted teeth, digital images) were compared (α = 0.05). RESULTS: Intra- and inter-rater kappa for ICDAS on teeth were 0.81-0.94 and on photographs 0.54-0.88, respectively. Correlation with histology was 0.58- 0.61 for the teeth and 0.50-0.62 for the photographs. AUC of ICDAS scores of extracted teeth (mean 0.89) were slightly higher than those for photographs (mean 0.84). However, both AUC values were not statistically significant (p = 0.38). CONCLUSION: Using photographs to assess occlusal surfaces with the ICDAS criteria was not statistically different from scoring the extracted teeth.

Remineralisation capability of silver diamine fluoride in artificial enamel lesions on smooth surfaces using quantitative light-induced fluorescence measurements in-vitro.

Enamel demineralisation can develop on smooth surfaces as an undesirable side effect during orthodontic treatment with fixed appliances. This study aimed to evaluate the ability of 38% silver diamine fluoride in remineralisation (as estimated by fluorescence gain) of artificial initial lesions in smooth surfaces of human enamel. The smooth surfaces of 50 human tooth samples were artificially demineralised and 45 samples were allocated randomly into three groups receiving a single treatment with a varnish: group I: Riva Star (silver diamine fluoride, SDF), group II: Bifluorid 12 (NaF, CaF2), and group III: Cervitec F (CHX, CPC, NH4F). Five samples were assigned as a negative control group without treatment. All samples were exposed to pH-cycling for 28 days. Fluorescence behavior was measured using Quantitative light-induced fluorescence before and after demineralisation and up to four weeks on a weekly basis. Analysis of variance (ANOVA) with Tukey-Kramer post-hoc tests and repeated measures ANOVA were used for statistical evaluation (α = 0.05). After demineralisation, all samples showed mean ΔF of - 16.22% ± 4.35, without significance differences between the fluorescence behaviour of the samples (p = 0.251). After 28 days group comparison showed a statistically significant difference (p = 0.034) for ΔF values: the lowest fluorescence values were found in group I (SDF, mean ΔF - 16.47 ± 6.08) with a significant difference compared to group III (Cervitec F, mean ΔF - 11.71 ± 4.83). In group II (Bifluorid 12) mean ΔF value was - 15.55 ± 2.15) without statistically significant differences to groups I and III. The fluorescence behaviour of SDF varnish on smooth surfaces with artificial initial enamel lesions was significantly lower compared to Cervitec F varnish after short time use.

Validity of an information and communication technology system for data capture in epidemiological studies.

The Belgian National Institute of Health Insurance is implementing an oral health data registration and surveillance system. This study aimed to develop and validate a system of electronic data capture for oral health surveys at a national level - Oral Survey-B - and to identify the advantages and disadvantages of the electronic system in comparison with the traditional handwritten data capture. Six series of full-mouth recordings simulating the clinical examination of 6 patients were set up in a Powerpoint presentation. The validation was undertaken by 52 general practitioners. A randomized one-period crossover design was used with two formats of data capture, i.e. electronic followed by handwritten or handwritten followed by electronic system. Further, 6 benchmarked handwritten forms were transferred to the electronic format. For the electronic data capture, 86.5% of the practitioners had a correct completion rate of ≥95%. The corresponding value for the handwritten data capture and transfer was 78.8% (p = 0.25, McNemar test). The overall accuracy of forms without any error was 73.4% for the electronic and 62.5% for the handwritten data capture (p < 0.001, signed-rank test). Significantly lower percentages of errors and less time were observed for the electronic data capture (p < 0.001, signed-rank test). Practitioners considered the electronic data capture as being much more difficult to carry out (p < 0.001). As information technology has turned into an ever more necessary working tool in epidemiology, there should be an important potential for uptake of further improvements in electronic data capture in the future.

Decision-making and preventive non-surgical therapy in the context of a European Core Curriculum in Cariology.

This paper is part of a series of papers towards a European Core Curriculum in Cariology for undergraduate dental students. The European Core Curriculum in Cariology is the outcome of a joint workshop of the European Organisation for Caries Research (ORCA) together with the Association for Dental Education in Europe (ADEE), which was held in Berlin from 27 to 30 June 2010. The present paper covers decision-making and non-surgical treatment. In particular, it will provide some background information on this part of the European core curriculum. The dentist, on graduation, must be competent at applying the principles of prevention of dental hard tissue disease processes (primary prevention) and progression when it has manifested itself (secondary prevention). The competences should apply in differing ways to patients of all ages. Goals of prevention should be clearly defined in order for outcomes to be evaluated, and a dentist should be competent at determining these outcomes. Although this concept is recognised by many academics and experts, clinical teaching, practice and health insurance coverage frequently emphasise surgical treatment. There are many reasons and obstacles that might account for this, and this paper suggests some reasons why this might be and makes suggestions for how these can be addressed in the future. One factor that is essential in the provision of a preventive, non-surgical approach is that of communication with the patient. However, this unfortunately takes less space in the dental curricula compared with technical skills aimed at restorative procedures; this weighting needs to be more equally balanced.

Associations between obesity, dental caries, erosive tooth wear and periodontal disease in adolescents: a case-control study.

PURPOSE: To compare oral health [dental caries, periodontal status, and erosive tooth wear (ETW)], diet and oral hygiene habits between obese and normal weight adolescents, and to explore possible risk associations. METHODS: In this case-control study, a convenience sample of 71 obese adolescents (age range 11-18) from a rehabilitation centre, and 54 age-sex-matched normal weight adolescents were selected for this study. Groups were defined using the Body Mass Index and growth curves for Flemish adolescents. Oral health was measured using DMFT, gingival, plaque and BEWE index. A validated questionnaire was utilized to assess diet and oral hygiene habits. Mann-Whitney U test was used to compare oral health between groups. Multivariate Firth's logistic regression analysis, conditional regression analysis and classification trees were used to detect associations between oral health and potential risk factors. RESULTS: Prevalence of ETW did not differ significantly between groups, although obese adolescents presented a significantly higher caries experience, gingivitis, presence of plaque and periodontal problems, compared to normal weight adolescents. After adjusting for age and sex, obesity was associated only with the presence of dental plaque (p ≤ 0.001). Obese participants reported a significantly higher intake of sugar-rich and caloric food items than normal weight group. The consumption of acidic drinks, however, was similar. CONCLUSION: Obese adolescents presented significantly higher caries experience, gingivitis and plaque, although after adjusting, obesity became significantly associated only with the presence of dental plaque.

Child behaviour during dental care under nitrous oxide sedation: a cohort study using two different gas distribution systems.

PURPOSE: Conscious sedation by inhalation of a mixture of nitrous oxide and oxygen (CS) is a technique used in dental care for anxious, handicapped or uncooperative patients. The very special objective of this cohort study is to compare the behaviour of young patients during dental care under CS in two hospitals using different gas distribution systems. METHODS: Young patients were divided into four categories: young child (YC), phobic anxiety (PA), mental disorder (MD), occasional indication (OI). Differences in behaviour scale at various time points according to the sedation system used were established and compared using Mann-Whitney tests. RESULTS: This study showed that there is no difference in behaviour during dental care in YC after sedation. In PA, a significant difference in behaviour is only observed during local anaesthesia (p = 0.024). CONCLUSION: No significant differences detected in children's behaviour under conscious sedation using different gas administration systems. The delicate stage of local anaesthesia in PA patients can be facilitated with repeated sessions of dental care under conscious sedation.

A prospective randomized clinical trial of one bis-GMA-based and two ormocer-based composite restorative systems in class II cavities: Five-year results.

OBJECTIVES: Ormocer composites, consisting of a silicon-based polymer, have been developed recently as a tooth-colored restorative material. The purpose of this prospective randomized clinical trial was to evaluate the performance of two small-particle hybrid ormocer-based restorative systems (AD, Admira/Admira Bond, VOCO; DE, Definite/Etch & Prime 3.0, Dentsply) and one small-particle hybrid bis-GMA-based composite restorative system (TC, Tetric-Ceram/Syntac, Ivoclar-Vivadent) in class II cavities. METHODS: From 128 occlusal-proximal restorations (44 AD, 43 DE and 41 TC) placed in 32 adult patients, eventually 77 (22 AD, 29 DE and 26 TC) remained available for evaluation after 5 years. Their clinical performance was scored according to the USPHS criteria and evaluation of bite-wing radiographs. RESULTS: After 5 years, eight AD, six DE and seven TC restorations had failed (p=0.10, log-rank test). The main reason was fracture or marginal gap formation, while secondary caries accounted for four failures. In all restorations the quality of surface, margins and contact point decreased significantly compared to baseline. DE had a significant poorer color match (p<0.01). Statistical evaluation using the KW test showed that failures were concentrated on specific patients. CONCLUSIONS: In a group of class II restorations, there was no significant difference in failures after 5 years between ormocer-based and bis-GMA-based restorative systems.

Randomised in situ clinical trial investigating self-assembling peptide matrix P11-4 in the prevention of artificial caries lesions.

The aim was to investigate the ability of self-assembling Peptide P11-4 Matrix (SAPM) to remineralize artificial initial caries lesions compared to the use of fluoride varnish. Volunteers were recruited for this randomised, cross-over in situ trial. Bovine specimens, half including orthodontic brackets, were recessed on the buccal aspects of mandibular appliances. Specimens included internal sound enamel control, a demineralised control and a part exposed during the in situ phase. Each phase lasted four weeks, followed by a one-week washout. Treatment groups were: A: negative control, no treatment,B: positive control, 22,600 ppm fluoride varnish,C: test group, 1,000 ppm SAPM. Laser fluorescence values (LF) were measured before/after demineralisation, and after the in situ period. Micro-CT analysis was used to assess mineral changes within the specimens after the in situ phase. In specimens without brackets, ΔLF values after in situ phase were: A: +5.28, B: +0.85, C: -2.89. Corresponding ΔLF for specimens with brackets were: A: +5.77, B: +1.30, C: -3.15. LF-values between groups significantly differed from each other (p < 0.0001) after the in situ phase. Micro-CT analysis yielded no significant difference among groups for specimens without brackets. For specimens with brackets, the test group showed significantly more remineralisation than the negative (p = 0.01) and positive control (p = 0.003). Within the limitations of the study, SAPM showed prevention of caries and remineralisation of enamel around orthodontic brackets.

Approximal caries diagnosis after data import from different digital radiography systems: interobserver agreement and comparison to histological hard-tissue sections.

AIMS: To evaluate the agreement of approximal caries diagnosis obtained with different types of digital radiography systems after image import into a reference system. METHODS: Digital radiographs were taken from 30 extracted human premolars with 60 diagnostic surfaces using a reference and two test systems from which images were imported as TIFF files. Four observers evaluated the radiographs using the reference software. Teeth were sectioned for histology. Agreement between histology and each technique was calculated using receiver operating characteristic (ROC) statistics. RESULTS: The areas under the ROC curves were not significantly different between reference and test systems. CONCLUSIONS: Importing files from different programs did not affect diagnostic accuracy.

A prospective randomised clinical trial of one bis-GMA-based and two ormocer-based composite restorative systems in class II cavities: three-year results.

OBJECTIVES: Ormocer composites, consisting of a silicon-based polymer, have been developed recently as a tooth-coloured restorative material. The purpose of this prospective randomised clinical trial was to evaluate the performance of two small-particle hybrid ormocer-based restorative systems (AD, Admira/Admira Bond, VOCO; DE, Definite/Etch & Prime 3.0, Dentsply) and one small-particle hybrid bis-GMA-based composite restorative system (TC, Tetric-Ceram/Syntac, Ivoclar-Vivadent) in occlusal stress-bearing restorations. METHODS: One hundred and twenty-eight occlusal-proximal restorations (44 AD, 43 DE and 41 TC) were placed according to the manufacturer's instructions in thirty-two adult patients. Their clinical performance was scored according to the USPHS criteria and evaluation of bite-wing radiographs. RESULTS: After 3 years, four AD, five DE and four TC restorations had failed due to fracture or marginal gap formation. Surface roughness improved significantly when compared to the baseline in AD and TC (Friedman test, p<0.05) during the first year but returned to baseline values after 3 years. DE had a significant tendency towards discolouration (p<0.05). Bite-wing radiographs showed two AD and one TC restorations with internal porosities. ANOVA showed that larger restorations (> or = 3 surfaces) showed significantly more degradation than smaller ones. CONCLUSIONS: In a group of class II restorations, there was no significant difference in failures after 3 years between ormocer-based and bis-GMA-based restorative systems.

Comparison of micro-CT imaging and histology for approximal caries detection.

Histological sectioning is a generally accepted in vitro validation method for caries detection techniques. However, it requires cumbersome sample preparation and induces irreversible sample destruction. Micro-Computer Tomography (micro-CT) allows non-destructive imaging of tooth structure. The aim of this study was to compare the performance of histological sectioning and micro-CT imaging in detecting approximal carious lesions. Unlike previous studies, evaluation is objectified by comparing visual appearance of exactly corresponding anatomical regions. Sixty extracted human teeth were scanned with a desktop micro CT system. Axial histological slices were prepared and photographed. Sample preparation, combined with dedicated image processing, ensured selection of identical anatomical regions on radiographic and histological images. Evaluation of the presence and extent of carious lesions was performed by four dentists using custom-designed software. Each section was scored independently (histo or micro CT). Scores of approximal surfaces were retained for further analysis. Spearman's correlation coefficients (0.738 to 0.829, p < 0.0001) showed a good agreement between signs of carious lesions in the identical region obtained with both methods. Bland-Altman plots showed that 90.76% of the data points were within the limits of agreement. Micro-CT imaging was shown to provide an interesting alternative to histological sectioning as detection method for carious lesions.

Distribution of fluoride in the oral cavity after application of a bioadhesive fluoride-releasing tablet.

Bioadhesive fluoride tablets are fluoride-releasing devices that can be applied to the oral mucosa by the patient and release fluoride for several hours. From earlier research, it is known that a single fluoride source in the mouth can lead to an uneven distribution of fluoride in the oral cavity. In this study, fluoride concentrations were determined at different sites of the oral cavities of 13 healthy human volunteers after the application of a bioadhesive fluoride tablet containing 0.5 mg fluoride. The sites were: (1) labial surfaces of the upper central incisors, (2) lingual surfaces of the lower central incisors, (3) labial surface of the first upper left molar, and (4) labial surface of the lower right first molar. The tablet was fixed either centrally on the palate or in the lower labial sulcus in two consecutive experiments. Saliva was sampled with polyethylene sponges 5, 10, 20, 30, 60, 120, 180, and 240 minutes after tablet insertion. Fluoride was determined electrochemically. It could be shown that the area under the curve (AUC) values were significantly (p < 0.05) higher after tablet insertion in the lower labial sulcus at sampling site 1, a trend (p = 0.06) could be calculated for sampling sites 2 and 3, and no difference was found at sampling site 4. Fluoride could be detected in concentrations above 0.01 mmol.L-1 at all sampling sites after tablet insertion in the lower labial sulcus. This location seems to be a more appropriate tablet location than the palate.

Development and testing of bioadhesive, fluoride-containing slow-release tablets for oral use.

The bioadhesive characteristics of tablets for oral use made from modified starch, polyacrylic acid (PAA), polyethylene glycol (PEG) and sodium carboxymethylcellulose (CMC) were investigated. Adhesion force and energy were determined in-vitro and maximal adhesion time was evaluated in-vivo in human subjects. In-vitro, PAA showed the best bioadhesive properties, followed by modified maize starch and PEG with a mol. wt of 300,000-400,000 daltons. The presence of 0.1 mg of fluoride as NaF did not lead to significant differences in adhesion force and energy for the same formulation. The in-vivo bioadhesion was not strongly correlated to the in-vitro data. PAA, despite its excellent adhesion, proved to be irritating to the mucosa. PEG with a mol, wt of 200,000 daltons was subject to erosion. CMC showed good bioadhesive properties but the mechanical strength of the tablets was low. Modified maize starch tablets containing 5% (w/w) PAA and PEG with a mol. wt of 300,000 daltons proved to be the most suitable formulations for a fluoride-slow-release tablet with bioadhesive properties. In-vitro, the tablets released all of the fluoride within the 8 h period, with a high initial release. The release rate was related to the water absorption rate of the tablets. The PAA-containing formulations and the CMC formulations had the fastest release. In-vivo, fluoride levels with a minimum of 150 and a maximum of 1000 micrograms mL-1 were maintained for 8 h in the oral cavity. These fluoride levels were sustained significantly longer than those obtained with the administration of fourfold the amount of fluoride in the form of a fluoride-containing toothpaste. The release characteristics in-vivo exhibited a high variation. The use of bioadhesive polymers in oral pharmacotherapy seems promising.

Comparison of salivary fluoride concentrations after administration of a bioadhesive slow-release tablet and a conventional fluoride tablet.

The in-vitro and in-vivo fluoride release of bioadhesive, slow-release tablets prepared from a mixture of polyethylene glycol polymers, containing 0.1 mg of fluoride as NaF was studied, and their ability to sustain fluoride levels in saliva were compared with conventional fluoride tablets with the same fluoride content. In-vitro release experiments showed that the bioadhesive tablets needed 8 h to release all their fluoride compared with less than 1 h for the conventional fluoride tablets. In-vivo, the bioadhesive tablets had a retention period of 6 h and could sustain a salivary fluoride level of more than 10 microM above the baseline for 7 h. The conventional fluoride tablets achieved a peak concentration of 0.5 mM directly after dissolution in the mouth, but the fluoride level could not be sustained for longer than 1 h. A good agreement was found between the in-vitro swelling behaviour of the bioadhesive tablets and their in-vitro and in-vivo release characteristics and their in-vivo retention time.

Penetration of etching agents and its influence on sealer penetration into fissures in vitro.

OBJECTIVES: This study was designed to assess: 1) the ability of several commercially available and laboratory-made acid etchants to penetrate occlusal fissures when used for pit and fissure sealing, and 2) the influence of adding a surfactant to the etchant on penetration of the sealer. Viscosity, surface tension and contact angle to enamel of the etchants were determined for each treatment, and these properties were related to the etchant's ability to penetrate fissures. METHODS: Penetration was assessed in an acrylic fissure model having a deep-narrow fissure using a microscope and a chronometer. Penetration depth was expressed as percentage of total fissure depth and was measured in intervals up to 90 s. Commercially available etching agents with different viscosities and two solutions of phosphoric acid (37%), one with and one without a surfactant, were tested. The etch pattern obtained on the fissure wall enamel of extracted teeth with some of these products was evaluated using scanning electron microscopy. Eventually, the penetration depths of a composite sealer in fissures treated with a conventional etchant were compared to those after application of a surfactant-containing etchant on sections of extracted teeth. RESULTS: None of the commercially available etchants studied were able to penetrate farther than 17% of the total fissure depth in the fissure model. The surfactant-containing etchant showed complete penetration within about 1 min and had a significantly lower surface tension and contact angle than the other products tested. Only the surfactant-containing etchant could produce a retentive pattern on the entire wall enamel of the fissure with the exception of locations blocked by debris and plaque. Fissures treated with this product prior to sealing showed a significantly deeper penetration of the sealer in deep-marrow fissures. SIGNIFICANCE: Surfactant-containing etchants with a low viscosity can penetrate completely into fissures and can produce an increased retentive and wettable surface which significantly increased sealant penetration into deep fissures.

Study of lead and cadmium content of surface enamel of schoolchildren from an industrial area in Belgium.

The amount of lead and cadmium was determined in surface enamel from permanent teeth of schoolchildren by means of an acid etch surface enamel microbiopsy method. Lead and cadmium levels were calculated on the amount of etched enamel. A comparison of the concentrations of these heavy metals was made between children (7 and 11 yr) from a school close to a non-ferrous metal plant and children from the same age group from a school situated nearby the same plant but in a zone polluted to a lesser degree. The lead concentrations in enamel biopsies from the first group were significantly higher than those from the second group. Cadmium shows the same trend but on a much lower level. A significant correlation between lead and cadmium was also found in both groups.

Longevity of posterior composite restorations: a systematic review and meta-analysis.

The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years' follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces.