Higher experience of caries and lower income trajectory influence the quality of restorations: A multilevel analysis in a birth cohort.

OBJECTIVES: This study aimed to evaluate the quality of posterior restorations (amalgam or composite) placed in adults from a birth cohort and its association with clinical and socioeconomic determinants experienced during their life course. METHODS: A representative sample (n=539) of all 5914 births occurring in Pelotas (Brazil) in 1982 was prospectively investigated. Quality of posterior restorations (satisfactory or unsatisfactory) was assessed at 31 yrs-old, using modified USPHS criteria. Trained and calibrated dentists performed clinical examination. Explanatory variables included demographic and socioeconomic, oral health and dental service utilization patterns during the life course. Tooth related variables (type of tooth, material, size of cavity) were also analyzed. Untreated caries and socioeconomic status were assessed by group-based trajectories analyses. Multilevel Regression models were used to determine factors associated with restoration outcomes. RESULTS: In total 2123 restorations (53% composite) were evaluated of which 107 (5%) were assessed as failed. The main reasons for failure were tooth/restoration fracture (50.5%) and secondary caries (30.7%). Failures in posterior restorations showed a significant association with socioeconomic aspects (lower tertile of income at age 30 - prevalence ratio (PR) 2.21 [95% CI 1.19-4.09]), clinical variables (trajectory of higher untreated caries - PR 2.11 [95% CI 1.23-3.61]) and also with tooth-related factors (Restorations involving three or more surfaces - PR 5.51 [95% CI 3.30-9.19]) after adjustment for each other. CONCLUSIONS: These findings suggest that, although tooth-related variables have an important role in restoration longevity, patient-related factors, such as socioeconomic variables and untreated caries are also associated with failure and should be taken into account when evaluating longevity of posterior restorations. CLINICAL SIGNIFICANCE: This was the first study assessing long-term trajectory of untreated caries, showing an association between higher experience of caries during the life-course and unsatisfactory restorations. The findings suggest that individual related factors should be considered when planning treatment and in future research evaluating the longevity of dental restorations.

Characterisation of secondary metal-bearing phases in used dental amalgam and assessment of gastric solubility.

Detailed SEM/EDS investigation of used dental amalgams was carried out in order to characterise morphology and chemical composition of secondary metal-bearing phases resulting from long-term exposure of dental amalgam to oral environment, and assess their solubility in gastric environment. The investigation revealed numerous secondary phases, represented by compositionally and morphologically complex Hg-, Cu-, Sn-, Ag-, Zn-bearing sulphides and oxides/hydroxides, while sulphates and phosphates are scarce. Secondary metal-bearing phases mostly occur at the amalgam/tooth interface; however, some phases were found only on the occlusal surfaces of amalgam. Secondary phases mostly form porous aggregates of minute crystallites and micro- or nanocrystalline crusts. In oral environment, these phases are mostly stable and represent trapping media for dissolved potentially toxic metals released during amalgam corrosion. Simplified PHREEQC calculations of solubility of secondary metal-bearing phases in aqueous environment under conditions similar to those in gastric environment showed that secondary phases are more soluble in gastric environment than in oral solutions, which is mostly due to their forms of occurrence. Secondary phases in gastric environment thus act as secondary sources of potentially toxic metals, particularly Sn, Zn and also Cu, which are released both under reducing and oxidising conditions especially in acidic environment. Only very small amounts of Hg are potentially released and should not represent serious threat. Secondary phases that contribute the most to bioaccessibility of these metals are Sn hydroxychlorides, Sn oxides/hydroxides, Sn sulphates/hydroxysulphates, Sn oxides, Zn sulphides and Cu sulphides (Cu2S).

An initial assessment of haptics in preclinical operative dentistry training.

AIM: The purpose of this study was to assess novice student perception of haptic-based manual dexterity training. The short-term impact of haptic training in the early phase of preclinical operative dentistry education was also investigated. METHODS: Dental students performed a class II amalgam and a class III resin tooth preparation in a typodont model at baseline. The experimental group performed exercises on the manual dexterity module of the IDEA™ software using a haptic device. The exercises required removing the maximum amount of three-dimensional geometric shapes within a predetermined width and depth. Tooth preparations were repeated 2 weeks later. A questionnaire survey was given to assess the subjective evaluation of the haptic simulation exercise. RESULTS: Tooth preparations were scored regarding external outline, internal form, and integrity of adjacent tooth. Improvement of overall tooth preparation scores post-haptic use was not statistically significant compared to controls (P > 0.05). However, students found the game-feature of the haptic device made the learning experience more fun and interesting. CONCLUSION: The haptic exercises with the manual dexterity module software were not superior in improving the dexterity of students for tooth cavity preparations in short-term. Benefits of ease of use and fun learning experience can be further investigated in future studies.

Do socioeconomic determinants affect the quality of posterior dental restorations? A multilevel approach.

OBJECTIVES: This study aimed to evaluate posterior restorations placed in young adults, investigating the association between social determinants experienced during the life course and the quality of tooth fillings. METHODS: A representative sample (n=720) of all 5914 individuals who were born in Pelotas in 1982 was prospectively investigated, and posterior restorations were assessed at 24 years of age. Exploratory variables included demographic and socioeconomic, oral health and dental service payment mode during the life course. Tooth-related variables (type of tooth, material and size of cavity) were also analysed. RESULTS: Multilevel logistic regression models showed that individuals who were always poor from birth to age 23 [odds ratio (OR) 2.35 (1.38-4.00)] and whose mothers had less years of education at their birth (OR 2.60 (1.44-4.68)) were with unsatisfactory restorations in posterior teeth more often. In addition, caries presence at age 15 (high decayed, missing, filled teeth (DMFT) tertile) (OR 1.95 (1.25-3.03)) and cavities with four or more surfaces (OR 18.67 (9.25-37.68)) were associated with the outcome. CONCLUSIONS: These results show that socioeconomic characteristics of the individuals play an important role in restoration failures, reinforcing the need for preventive dental strategies and public policies to reduce inequalities as a major topic of oral health. In addition, the size of cavity appears as the most important determinant for restoration failure. CLINICAL SIGNIFICANCE: Individual socioeconomic characteristics were associated with failure in posterior restorations in detriment of other clinical variables such as restorative material and type of tooth.

Ultrashort echo time (UTE) MRI for the assessment of caries lesions.

OBJECTIVE: Direct in vivo MRI of dental hard tissues by applying ultrashort echo time (UTE) MRI techniques has recently been reported. The objective of the presented study is to clinically evaluate the applicability of UTE MRI for the identification of caries lesions. METHODS: 40 randomly selected patients (mean age 41 ± 15 years) were enrolled in this study. 39 patients underwent a conventional clinical assessment, dental bitewing X-ray and a dental MRI investigation comprising a conventional turbo-spin echo (TSE) and a dedicated UTE scan. One patient had to be excluded owing to claustrophobia. In four patients, the clinical treatment of the lesions was documented by intraoral pictures, and the resulting volume of the cavity after excavation was documented by dental imprints and compared with the MRI findings. RESULTS: In total, 161 lesions were identified. 157 (97%) were visible in the UTE images, 27 (17%) in the conventional TSE images and 137 (85%) in the X-ray images. In total, 14 teeth could not be analysed by MR owing to artefacts caused by dental fillings. All lesions appear significantly larger in the UTE images as compared with the X-ray and TSE images. In situ measurements confirm the accuracy of the lesion dimensions as observed in the UTE images. CONCLUSION: The presented data provide evidence that UTE MR imaging can be applied for the identification of caries lesions. Although the current data suggest an even higher sensitivity of UTE MRI, some limitations must be expected from dental fillings.

Assessment of the release of mercury from silver amalgam alloys exposed to different 10% carbamide peroxide bleaching agents.

This in vitro study assessed the amount of mercury (Hg) released from a silver amalgam alloy following the application of different 10% carbamide peroxide bleaching agents. A total of 30 specimens (2 mm thick x 4 mm in diameter) were stored in deionized water at 37°C for 7 days. Next, the control group (n = 10) remained in the deionized water for 15 days, while the remaining samples were exposed to 1 of 2 bleaching agents (n = 10) for 8 hours daily (total exposure = 120 hours); for the remaining 16 hours, specimens in the test groups were stored in deionized water at 37°C under relative humidity. After this period, the quantity of Hg in the deionized water was assessed (using atomic absorption spectrophotometry) and compared to the amount of Hg at baseline. The results indicate that exposing amalgam alloys to bleaching agents released greater amounts of Hg compared to exposing samples to deionized [corrected] water.

Amalgam or composite resin? Factors influencing the choice of restorative material.

OBJECTIVES: This study aimed to investigate the patient and tooth factors associated with selection of restorative material in direct posterior restorations in young adults from a population-based birth cohort. METHODS: A representative sample (n=720) of all 5914 births occurring in Pelotas in 1982 were prospectively investigated, and posterior restorations were assessed in 2006, when the patients were 24 years old. Tooth-related variables (individual level) included restorative material (amalgam or composite), type of tooth, size of cavity, and estimated time in mouth. Data regarding demographic and socio-economic characteristics, oral health, and service utilization patterns during the life course were also assessed (contextual level). RESULTS: Logistic Regression Multilevel models showed that individuals who have accessed dental services by private insurance by age 15 [odds ratio (OR)=1.66 (0.93-2.95)] and who had a higher dental caries index at age 15 (high DMFT tertile) [OR 2.89 (1.59-5.27)] presented more amalgam restorations in the posterior teeth. From tooth-level variables, the frequency of amalgams decreases with increasing number of surfaces enrolled in the cavity preparation (p<0.001) and was almost 5 times greater in molars than in premolars. CONCLUSIONS: The present findings suggest that variables related to type of dental service, dental caries (higher DMFT index), and cavity characteristics (tooth type, size) determine the choice of dentists for restorative materials. Other individual characteristics such as demographic and socioeconomic status have not influenced this choice. CLINICAL SIGNIFICANCE: This is the first population-based study that assesses the determinant factors for the choice of dentists for composite or amalgam in posterior direct restorations, showing that, independently of socioeconomic and demographic characteristics, type of payment of dental services and clinical factors are associated with this choice.

Differences between reported and actual restored caries lesion depths: results from The Dental PBRN.

OBJECTIVE: The objectives of this research were to (1) quantify the discordance between the caries lesion depth at which dentists restored initial lesions during a clinical study ("actual depth") and the lesion depth that they reported during a hypothetical clinical scenario ("reported depth"); (2) test the hypothesis that certain practitioner, practice, patient, and caries lesion characteristics are significantly associated with this discordance. METHODS: Practitioner-investigators who perform restorative dentistry in their practices completed an enrollment questionnaire and participated in two consecutive studies on caries diagnosis and treatment. The first study was a survey asking about caries treatment. The second study collected data on restorations placed in routine clinical practice due to caries in patients over 19 years of age on occlusal surfaces only or proximal surfaces only. We report results on 2691 restorations placed by 205 dentists in 1930 patients with complete data. RESULTS: Discordance between actual depth and reported depth occurred in only about 2% of the restorations done due to proximal caries, but about 49% of the restorations done due to occlusal caries. Practice type, restorative material used and the diagnostic methods used were significantly associated with discordance. CONCLUSION: Dentists frequently restored occlusal caries at a shallower depth as compared to their reported depth, but the discordance was very small for proximal lesions. Discordance for occlusal caries was more common when radiographs were not taken or if a resin restoration was placed.

A significant relationship between mercury exposure from dental amalgams and urinary porphyrins: a further assessment of the Casa Pia children's dental amalgam trial.

Previous studies noted specific changes in urinary porphyrin excretion patterns associated with exposure to mercury (Hg) in animals and humans. In our study, urinary porphyrin concentrations were examined in normal children 8-18 years-old from a reanalysis of data provided from a randomized, prospective clinical trial that was designed to evaluate the potential health consequences of prolonged exposure to Hg from dental amalgam fillings (the parent study). Our analysis examined dose-dependent correlations between increasing Hg exposure from dental amalgams and urinary porphyrins utilizing statistical models with adjustments for the baseline level (i.e. study year 1) of the following variables: urinary Hg, each urinary porphyrin measure, gender, race, and the level of lead (Pb) in each subject's blood. Significant dose-dependent correlations between cumulative exposure to Hg from dental amalgams and urinary porphyrins associated with Hg body-burden (pentacarboxyporphyrin, precoproporphyrin, and coproporphyrin) were observed. Overall, 5-10% increases in Hg-associated porphyrins for subjects receiving an average number of dental amalgam fillings in comparison to subjects receiving only composite fillings were observed over the 8-year course of the study. In contrast, no significant correlations were observed between cumulative exposure to Hg from dental amalgams and urinary porphyrins not associated with Hg body-burden (uroporphyrin, heptacarboxyporphyrin, and hexacarboxyporphyrin). In conclusion, our study, in contrast to the no-effect results published from the parent study, further establishes the sensitivity and specificity of specific urinary porphyrins as a biomarker for low-level Hg body-burden, and also reveals that dental amalgams are a significant chronic contributor to Hg body-burden.

Differences in pediatric dental services under general anesthesia for Medicaid and military dependent children.

PURPOSE: This study's purpose was to compare pediatric dental services provided for Medicaid and military dependent children to determine if differences in dental treatment choices exist based on site and payment method. METHODS: Subjects included 120 Medicaid patients at the University of Texas Health Science Center at San Antonio and 120 military dependents at Lackland Air Force Base, Texas. Demographic data and treatment information were abstracted for children younger than 6 years old receiving dental treatment under general anesthesia between 2002 and 2006. Data was analyzed using Wilcoxon rank sum, Kruskal-Wallis, and Fisher's exact tests. RESULTS: The Medicaid recipients were younger (40.2 vs 49.8 months, P<.001) and more likely to be Hispanic (78% vs 30%, P<.001). The means of decayed teeth, fillings, and stainless steel crowns did not differ between sites. Medicaid children received more composite fillings (P<.001), fewer amalgam fillings (P<.001), fewer pulp therapies (P<.001), more extractions (P=.01), and fewer sealants (P<.001). Age and gender did not affect decay rates, but those of Hispanic ethnicity did experience more decay than non-Hispanics (9.5 vs 8.6, P=.02). CONCLUSION: This study found no difference in the number of less conservative, albeit more costly, procedures performed with Medicaid children at a university compared to military dependents at a military base.

Teaching of direct posterior resin composite restorations in UK dental therapy training programmes.

AIM: With the numbers of dental therapists involved in the delivery of dental care within the UK on the increase, and the trend towards the use of direct resin composites (composites) for the restoration of posterior teeth, this study was undertaken to describe the teaching of posterior composites in dental therapy training programmes in the UK. A secondary aim was to identify differences in techniques for posterior composites taught within these dental therapy training programmes. METHODS: In 2008/9, a questionnaire seeking information on the teaching of posterior composites was distributed by email to 13 centres with dental therapy training programmes in the UK. This questionnaire sought information relating to the teaching of direct posterior composites to dental therapy students, including the amounts of preclinical and clinical teaching in respect of deciduous and permanent teeth, numbers of restorations placed, contraindications to placement, and details in respect of operative techniques. RESULTS: Ten completed responses were received (response rate = 77%). In ten programmes, student dental therapists received clinical training in the placement of composite restorations in the occlusal surfaces of premolar and permanent molar teeth, and nine programmes included such training for two and three surface occlusoproximal restorations. The mean proportions of posterior restorations placed clinically by the trainee dental therapists in permanent teeth using dental amalgam and composite were 52% and 46% respectively (range: amalgam = 20-95%; composite = 5-70%). CONCLUSION: With the exception of one programme, the teaching of posterior composites is a well established element of dental therapy training. Some variations were noted in the teaching of clinical techniques between respondent training centres. It is suggested that to ensure harmony in approaches to treatments provided by graduated therapists that training centres look to relevant consensus documents, such as those of the British Association for the Teaching of Conservative Dentistry. The findings of our study are important for the future provision of oral healthcare, given the growing evidence base in favour of minimally invasive dentistry.

Neuropsychological function in school-age children with low mercury exposures.

The EPA reference dose for methylmercury (MeHg) was established using data from populations with greater exposures than those typical of the US. Few data are available on potential adverse health effects at lower levels. We examined relationships between hair mercury (Hg) levels and neuropsychological outcomes in a population of US children. This study included data from 355 children ages 6-10 enrolled in the New England Children's Amalgam Trial. Data on total hair Hg levels, sociodemographic information and neuropsychological function were collected. We evaluated associations between hair Hg and neuropsychological test scores with linear regression methods and used generalized additive models to determine the shape of associations that departed from linearity. Models controlled for relevant covariates, including the potential beneficial effects of consuming fish. In adjusted models, we observed no significant linear relationships between hair Hg level and any test score. Significant departures from linearity were identified for WIAT Math Reasoning and WRAMVA Visual-Motor Composite scores. The association was positive for hair Hg levels below 0.5 microg/g and negative for levels between 0.5 and 1.0 microg/g. Overall, test scores of children with hair Hg levels 1.0 microg/g appeared to be lower than those of children with levels < 1.0 microg/g, but few children had levels in this upper range and these differences did not reach statistical significance. Hair Hg levels below 1.0 microg/g in US school-age children were not adversely related to neuropsychological function.

Current paradigm shifts in dentistry.

It is a time of revolution and innovation in dentistry. Many of the ongoing changes are significant, while others are less influential. I have discussed numerous observable and inevitable paradigm shifts. Dentists are advised to note the ongoing trends, become educated about them, evaluate the importance of the changes in their individual practices and to their patients, and to integrate these changes into practice.

Cost-effectiveness of removing amalgam from dental wastewater.

Mercury in the form of amalgam is commonly introduced into dental wastewater as a result of amalgam placements and removals. Dental wastewater is primarily discharged to municipal sewers that convey industrial and residential wastewater to publicly owned treatment works (POTWs) for treatment prior to discharge to surface waters. In some localities, the sewage sludge generated by POTWs from the treatment of wastewater is incinerated, resulting in the emission of mercury to the atmosphere. Some of the mercury emitted from the incinerators is deposited locally or regionally and will enter surface waters. An assessment was conducted of the use of mercury in amalgam in California and the discharge of that mercury from dental facilities to surface waters via the effluent from POTWs and air emissions from sewage sludge incinerators (SSIs). The annual use of mercury in amalgam placements conducted in California was estimated to be approximately 2.5 tons. The annual discharge of mercury in the form of amalgam from dental facilities to POTWs as a result of amalgam placements and removals was estimated as approximately one ton. The discharge of mercury to surface waters in California via POTW effluents and SSI emissions was estimated to total approximately 163 pounds. A cost-effectiveness analysis determined that the annual cost to the California dental industry to reduce mercury discharges to surface waters through the use of amalgam separators would range from 130,000 dollars to 280,000 dollars per pound.