Dental amalgam fillings: An under-investigated source of mercury exposure

Dental amalgam fillings, which contain about 50% mercury, have been used since the early 19th century. However, their use has been controversial, particularly because they continually release small amounts of mercury. Inorganic mercury is known to be highly toxic, particularly to the nervous system and kidneys, but exposures from amalgam fillings are generally well below those established as toxic. However, uncertainties about threshold concentrations of effect and the nature of any long-term exposure effects remain. Considering the long-standing and widespread use of these fillings, there has been remarkably little investigation of their safety and most epidemiologic studies have been relatively recent. In general, investigations to date have shown little evidence of effects on general chronic disease incidence or mortality. There have been few studies so far of neurodegenerative diseases and results have been equivocal. Assessments of the safety of dental amalgam have mainly been based on studies of occupationally exposed populations. However, the amalgam-exposed population contains a broader, potentially more susceptible, spectrum of people. In that regard, a number of studies of children that have found no evidence of health effects have provided some reassurance

Multidimensional screening for predicting pain problems in adults : a systematic review of screening tools and validation studies

Screening tools allowing to predict poor pain outcomes are widely used. Often these screening tools contain psychosocial risk factors. This review (1) identifies multidimensional screening tools that include psychosocial risk factors for the development or maintenance of pain, pain-related distress, and pain-related disability across pain problems in adults, (2) evaluates the quality of the validation studies using Prediction model Risk Of Bias ASsessment Tool (PROBAST), and (3) synthesizes methodological concerns. We identified 32 articles, across 42 study samples, validating 7 screening tools. All tools were developed in the context of musculoskeletal pain, most often back pain, and aimed to predict the maintenance of pain or pain-related disability, not pain-related distress. Although more recent studies design, conduct, analyze, and report according to best practices in prognosis research, risk of bias was most often moderate. Common methodological concerns were identified, related to participant selection (eg, mixed populations), predictors (eg, predictors were administered differently to predictors in the development study), outcomes (eg, overlap between predictors and outcomes), sample size and participant flow (eg, unknown or inappropriate handling of missing data), and analysis (eg, wide variety of performance measures). Recommendations for future research are provided

Dental amalgam and mercury in dentistry

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Mercury in dentistry has re-emerged as a contentious issue in public health, predominantly because so many people are inadvertently exposed to mercury in order to obtain the benefits of dental amalgam fillings, and the risks remain difficult to interpret. This commentary aims to examine the issues involved in public policy assessment of the continued use of dental amalgam in dentistry.AJ Spence

The Relation between the Fear-Avoidance Model and Constructs from the Social Cognitive Theory in Acute WAD

In the fear-avoidance (FA) model social cognitive constructs could add to explaining the disabling process in whiplash associated disorder (WAD). The aim was to exemplify the possible input from Social Cognitive Theory on the FA model. Specifically the role of functional self-efficacy and perceived responses from a spouse/intimate partner was studied. A cross-sectional and correlational design was used. Data from 64 patients with acute WAD were used. Measures were pain intensity measured with a numerical rating scale, the Pain Disability Index, support, punishing responses, solicitous responses, and distracting responses subscales from the Multidimensional Pain Inventory, the Catastrophizing subscale from the Coping Strategies Questionnaire, the Tampa Scale of Kinesiophobia, and the Self-Efficacy Scale. Bivariate correlational, simple linear regression, and multiple regression analyses were used. In the statistical prediction models high pain intensity indicated high punishing responses, which indicated high catastrophizing. High catastrophizing indicated high fear of movement, which indicated low self-efficacy. Low self-efficacy indicated high disability, which indicated high pain intensity. All independent variables together explained 66.4% of the variance in pain disability, p<0.001. Results suggest a possible link between one aspect of the social environment, perceived punishing responses from a spouse/intimate partner, pain intensity, and catastrophizing. Further, results support a mediating role of self-efficacy between fear of movement and disability in WAD

Transcriptional and physiological response of Nitrosomonas europaea to inhibition by chlorinated aromatics and heavy metals

This research investigates the physiological and transcriptional responses of Nitrosomonas europaea when exposed to chlorinated aromatic compounds and heavy metals under varying environmental conditions. It was found that transcriptional responses of identified sentinel genes correlate well with nitrification inhibition. Sorption of metals to biomass was also investigated and found not to correlate well with N. europaea inhibition. Whole genome microarray experiments were performed to define the transcriptional response of N. europaea when exposed to chlorobenzene. 13 out of 2460 N. europaea genes were significantly up-regulated after a 1-hour exposure to 4 μM chlorobenzene. HPLC analysis revealed that chlorobenzene was being oxidized primarily into 4-chlorophenol, and further physiological studies revealed that the presence of 4-chlorophenol could account for the inhibitory responses observed. RT-qPCR analysis of several differentially regulated genes verified that similar transcriptional responses were occurring for both chlorobenzene and 4-chlorophenol. 50% inhibitory concentrations of chlorobenzene and 4-chlorophenol resulted in moderate up-regulation of studied genes, however, increasing the concentration of 4-chlorophenol to achieve nitrification inhibition of 93% or more dramatically increased the fold regulation of several of the identified up- and down- regulated genes of interest. Increasing the 4-chlorophenol exposure time to 3 hours at the higher inhibition levels led to a general decrease in amplitude of transcriptional response for all genes tested. Cultures of N. europaea were exposed to various amounts of cadmium in aqueous solution containing EDTA, a strong metal-chelating organic, to control free ionic cadmium²⁺ (Cd²⁺) concentrations. Inhibition of ammonia oxidation as well as transcriptional up-regulation of merA, an identified sentinel gene for exposure to cadmium was found to correlate well with the concentration of Cd²⁺. The concentration of Cd²⁺ required to significantly affect N. europaea cells was found to be in the nanomolar range, which is several orders of magnitude lower than values reported in the literature for cadmium inhibition to mixed-culture activated sludge systems. The sorption of cadmium to the cells was found to be proportional to both the concentration of total cadmium and the concentration of Cd²⁺. At the concentration of metals required to cause approximately 50% nitrification inhibition, specific oxygen uptake results indicate the inhibition is specific to AMO with HAO and downstream energy-generation processes intact. To investigate more closely the inhibitory interactions between heavy metals and AMO, N. europaea inhibition by cadmium, zinc and silver was studied under substrate-limiting conditions. Unlike incubation in oxic environments, 1 hour incubations of N. europaea with cadmium and silver under anoxic conditions did not cause inhibition of nitrification activity after re-suspension in oxic media. In contrast, zinc, which is normally considered an analogue of cadmium in terms of toxic effect and transport mechanisms, was non-inhibitory to N. europaea when exposed in media lacking ammonia. Transcriptional response of merA closely followed the inhibition patterns, with samples which were inhibited after the removal of the metal having significant up-regulation of the gene, and those samples which were uninhibited showing no significant change in merA transcript levels compared to controls. Although sorbed metal concentrations were not found to be predictive of either extent of inhibition or transcriptional response, significantly more cadmium, zinc and silver were sorbed to biomass when incubated in aerobic media compared to anoxic media. Sorption in oxic media was found to be independent of AMO activity and similar results were obtained using Deinococcus radiodurans, a non-nitrifying gram-positive extremophile. The results indicate that greater heavy metal sorption to biomass in oxic environments may be due to general membrane chemistry effects.Keywords: Silver, Heavy metal, Nitrifier, Chlorinated aromatic, Zinc, Transcript, mRNA, Cadmium, Nitrosomonas europaea, NItrificatio

Are we passing the acceptable? Standard setting of theoretical proficiency tests for foreign-trained dentists

Introduction Dentists educated outside the EU, EEA and Switzerland have the option to undergo proficiency testing to practice dentistry in Sweden. A standardised evidence-based procedure for proficiency tests is crucial. This paper explores if the standard setting of the theoretical examination in the Swedish proficiency test for foreign dentists is fit to differentiate candidates who meet the acceptable standard for licensure from those who do not, by analysis of inter-rater reliability and credibility of Angoff panels and the test's ability to differentiate candidates regarding learning outcomes and dental disciplines. Materials and Methods In a cohort study design, test results were collected from seven examinations during 2018–2019 (n = 316), combined with Angoff judgements and demographic data from The National Board of Health and Welfare. Intraclass correlation, Pearson correlation and linear regression were calculated. Results All exams demonstrated substantial judge inter-rater reliability using the Angoff procedure (0.65–0.82). Item difficulty predicted by the expert panels showed significant positive correlations with the item difficulty by candidate results (0.69–0.77). Candidates who did not meet the requirements for pass mark in the theoretical test revealed a significantly reduced performance overall in professional qualifications (i.e., learning outcomes) and reduced performance within dental disciplines. Conclusions The results indicate that a modified Angoff method is a feasible, simple, and defensible method for setting the pass mark for the theoretical examinations. The standard setting appears to differentiate candidates who do not meet the requirements of the professional qualifications of the dental degree. Adjustments could be undertaken to further discriminate for competence within single dental disciplines.publishedVersio

Periodontal conditions and incident dementia: a nationwide Swedish cohort study

Background Periodontal disease has been proposed as a putative etiological factor for dementia. The aim of this investigation was to compare the incidence of dementia in individuals with or without deep probing pocket depths (DPPD), serving as a proxy for periodontitis. Methods In this cohort study, conducted in Sweden, we identified 7992 individuals with DPPD and 29,182 matched individuals without DPPD (non-DPPD), using the Swedish Quality Registry for Caries and Periodontal Diseases (SKaPa). The two groups were followed for incident dementia (mean follow-up time was 7.6 years) based on data from the Swedish Dementia Registry (SveDem). The exposure-outcome relationship was explored by applying the Royston-Parmar (RP) flexible parametric survival model. Results The incidence of dementia in the two groups was similar. In the DPPD group 137 (1.7%) developed dementia and 470 (1.6%) in the non-DPPD group. The incidence rate of dementia was estimated to be 2.3 per 1000 person-years (95% confidence interval [CI] 1.9 to 2.7) in the DPPD group and 2.1 per 1000 person-years (95% CI 1.9 to 2.3) in the non-DPPD group. The RP model disclosed no association between DPPD and dementia incidence after controlling for potential confounders (the exponentiated coefficient was estimated to 1.13 [95% CI = 0.39 to 3.24]). Conclusion In this sample, no association was revealed between deep probing pocket depths and the incidence of dementia.Peer reviewe

Changes in health complaints after removal of amalgam fillings

The aim of the present study was to investigate whether removal of all amalgam fillings was associated with long-term changes in health complaints in a group of patients who attributed subjective health complaints to amalgam fillings. Patients previously examined at the Norwegian Dental Biomaterials Adverse Reaction Unit were included in the study and assigned to a treatment group (n = 20) and a reference group (n = 20). Participants in the treatment group had all amalgam fillings replaced with other restorative materials. Follow-ups took place 3 months, 1 and 3 years after removal of all amalgam fillings. There was no intervention in the reference group. Subjective health complaints were measured by numeric rating scales in both groups. Analysis of covariance was used to compare changes in health complaints over time in the two groups. In the treatment group, there were significant reductions in intra-oral and general health complaints from inclusion into study to the 3-year follow-up. In the reference group, changes in the same period were not significant. Comparisons between the groups showed that reductions in intra-oral and general health complaints in the treatment group were significantly different from the changes in the reference group. The mechanisms behind this remain to be identified. Reduced exposure to dental amalgam, patient-centred treatment and follow-ups, and elimination of worry are factors that may have influenced the results

Exercise therapy, manual therapy, or both, for osteoarthritis of the hip or knee: a factorial randomised controlled trial protocol

<p>Abstract</p> <p>Background</p> <p>Non-pharmacological, non-surgical interventions are recommended as the first line of treatment for osteoarthritis (OA) of the hip and knee. There is evidence that exercise therapy is effective for reducing pain and improving function in patients with knee OA, some evidence that exercise therapy is effective for hip OA, and early indications that manual therapy may be efficacious for hip and knee OA. There is little evidence as to which approach is more effective, if benefits endure, or if providing these therapies is cost-effective for the management of this disorder. The MOA Trial (Management of OsteoArthritis) aims to test the effectiveness of two physiotherapy interventions for improving disability and pain in adults with hip or knee OA in New Zealand. Specifically, our primary objectives are to investigate whether:</p> <p>1. Exercise therapy versus no exercise therapy improves disability at 12 months;</p> <p>2. Manual physiotherapy versus no manual therapy improves disability at 12 months;</p> <p>3. Providing physiotherapy programmes in addition to usual care is more cost-effective than usual care alone in the management of osteoarthritis at 24 months.</p> <p>Methods</p> <p>This is a 2 × 2 factorial randomised controlled trial. We plan to recruit 224 participants with hip or knee OA. Eligible participants will be randomly allocated to receive either: (a) a supervised multi-modal exercise therapy programme; (b) an individualised manual therapy programme; (c) both exercise therapy and manual therapy; or, (d) no trial physiotherapy. All participants will continue to receive usual medical care. The outcome assessors, orthopaedic surgeons, general medical practitioners, and statistician will be blind to group allocation until the statistical analysis is completed. The trial is funded by Health Research Council of New Zealand Project Grants (Project numbers 07/199, 07/200).</p> <p>Discussion</p> <p>The MOA Trial will be the first to investigate the effectiveness and cost-effectiveness of providing physiotherapy programmes of this kind, for the management of pain and disability in adults with hip or knee OA.</p> <p>Trial registration</p> <p>Australian New Zealand Clinical Trials Registry ref: ACTRN12608000130369.</p