White matter abnormalities mediate the association between masticatory dysfunction and cognition among older adults.

BACKGROUND: Masticatory parameters, such as reduced number of teeth and posterior contacts, have been shown to be associated with reduced cognitive status. The underlying mechanisms that affect these associations, are however, not well understood. OBJECTIVES: The study aims to investigate the association between masticatory dysfunction and cognition and explore the mediating effect of brain structure. METHODS: In this cross-sectional study, 45 older adults with subjective masticatory dysfunction (mean age 72.3 ± 4.0 years) were included. Mini-Mental State Examination score <25, brain trauma, neurological disease, neurodegenerative disorders, depression or poor Swedish language skills were criteria for exclusion. Cognitive functions (executive function and episodic memory) and masticatory dysfunction defined by functional occluding status (FOS; the number of occluding units and number of remaining teeth) were analysed with partial correlation models. Structural magnetic resonance imaging was performed on 28 feasible participants. Multiple regression analyses were performed to evaluate the predictive value of brain structure and white matter hypointensities (WM-hypo) on cognitive functions. A mediation analysis was applied to assess significant predictor/s of the association between FOS and cognition. RESULTS: Both episodic memory and executive functions were positively correlated with FOS. WM-hypo predicted cognitive status (executive function, p ≤ .01). WM-hypo mediated 66.6% (p = 0.06) of the association between FOS and executive functions. CONCLUSION: Associations between FOS and cognitive functions are reported, where FOS, a potential modifiable risk factor, was related to both episodic memory and executive functions. The mediating effect of WM-hypo on the association between FOS and executive functions highlights the impact of the vascularisation of the brain on the link between mastication and cognition. The present study provides increased knowledge that bridges the gap between masticatory dysfunction and cognition.

Orofacial dysfunction after stroke-A multidisciplinary approach.

OBJECTIVE: This paper describes the study protocol in an ongoing clinical trial evaluating oral screen training as part of a post-stroke rehabilitation programme. Baseline data were related to four domains: dysphagia, lip function, masticatory performance and patient-related outcome measures (PROM). BACKGROUND: Stroke is one of the most common causes of disability-adjusted life years, and dysphagia is a common remaining problem after stroke. Rehabilitation using oral screen training has been suggested to improve swallowing, but evidence is still insufficient. MATERIALS AND METHODS: Patients diagnosed with stroke with persisting objective and/or subjective swallowing dysfunction after primary rehabilitation were assessed for eligibility. In total, 25 patients were included. Objective function was assessed by swallowing capacity test (SCT), lip force and masticatory performance, subjective function by EAT-10 and NOT-S and PROM by LiSat-11 and ESAS. RESULTS: Baseline data presented a heterogeneous pattern with no significant association between objective and subjective dysfunction. Most of the participants (20/25) showed impaired swallowing capacity in SCT, and 23/24 revealed orofacial dysfunction according to NOT-S. The most common subjective item reported was chewing and swallowing problems (19/24). CONCLUSION: The heterogenous findings in the included tests and the lack of correlations emphasise the importance of multidisciplinary approaches to identify objective and subjective orofacial post-stroke dysfunction in clinical practice to be able to offer evidence-based individualised care. The included participants were representative of stroke patients with dysphagia, which supports proceeding with the planned intervention.

Metabolic surgery and oral health: A register-based study.

OBJECTIVE: The impact of weight loss surgery on oral health is not clear. The aim of the present study was to investigate its impact on the risk for dental interventions. MATERIALS AND METHODS: All adults who underwent metabolic surgery in Sweden between January 1, 2009 and December 31, 2018 were identified in the Scandinavian Obesity Surgery Registry (SOReg; n = 53,643). A control cohort from the general population was created, matched 10:1 on sex, age and place of residence (n = 536,430). All individuals were followed in the Swedish Dental Register regarding event rates for four types of dental intervention: restorative, endodontic and periodontal interventions, and tooth extractions. RESULTS: The surgical cohort had increased interventional rates postoperatively regarding all studied outcomes except periodontal interventions. Dental interventions were more common in the surgical cohort both pre- and postoperatively. The difference between the groups increased markedly in the postoperative period. The between-group comparison postoperatively showed increased event rates for restorations (IRR 1.8; 95% CI 1.7-1.8), extractions (1.9; 95% CI 1.9-2.0) and endodontics (2.1; 95% CI 2.0-2.1). CONCLUSION: The surgical intervention might cause a substantial negative impact on oral health. These results imply an important role for counselling metabolic surgery patients regarding preventive oral health measures.

Effects of primary hyperparathyroidism on oral health. A longitudinal register-based study.

OBJECTIVES: To analyze the effects of primary hyperparathyroidism on oral health and to investigate if the effects are linked to severity of the disease. SUBJECTS AND METHODS: This prospective cohort study involved 6151 primary hyperparathyroidism patients registered in the Scandinavian Quality Registry of Thyroid, Parathyroid, and Adrenal surgery and the National Cancer Register after parathyroidectomy (exposure) during 2011-2017 (patient cohort) and 60,654 individuals without primary hyperparathyroidism (reference cohort), matched by age, gender, and county of resident at the date of parathyroidectomy. The outcomes were tooth extractions and periodontal interventions. The risk for the outcomes was assessed by Poisson regression models. RESULTS: After adjusting for covariates, the patient cohort had a higher incidence rate of tooth extraction during the two-year period after parathyroidectomy (IRR = 1.15; 95% CI = 1.01-1.31), but a lower incidence rate of periodontal interventions during the four- to six-year period after parathyroidectomy (IRR = 0.88; 95% CI = 0.79-0.99). Furthermore, patients with more severe primary hyperparathyroidism were more likely to have tooth extractions and periodontal interventions after parathyroidectomy. CONCLUSIONS: The risk of tooth extraction increased slightly during the first two years after parathyroidectomy. Thereafter, the oral health effects subsided. Pre-surgical serum ionized calcium levels and adenoma weight may indicate negative dental outcomes after parathyroidectomy.

Poor dental health and risk of pancreatic cancer: a nationwide registry-based cohort study in Sweden, 2009-2016.

BACKGROUND: Previous studies have reported inconsistent results regarding the association between poor dental health and pancreatic cancer risk. This study aimed to assess this association using a well-functioning nationwide dental health registry in Sweden. METHODS: Information of exposures (dental caries, root canal infection, mild inflammation, and periodontitis; the number of teeth) was ascertained from the Swedish Dental Health Register, and occurrence of pancreatic cancer was identified from both cancer and cause of death registries. Hazard ratios (HRs) were estimated using Cox models. RESULTS: During a median of 7.2 years of follow-up, 10,081 pancreatic cancers were identified among 5,889,441 individuals. Compared with the healthy status, a higher risk of pancreatic cancer was observed in individuals with root canal infection, mild inflammation, and periodontitis in the <50 age group (P for trend <0.001). In the 50-70 age group, only the subgroup with periodontitis had an excess risk (multivariable-adjusted HR = 1.20, 95% confidence interval [CI] 1.11-1.29). No positive association with statistical significance was observed in the 70+ age group. Individuals with fewer teeth tended to have a higher risk in all age groups. CONCLUSIONS: Our results confirmed the association between poor dental health and pancreatic cancer risk, which warrants further studies on underlying mechanisms.

Chewing and its influence on swallowing, gastrointestinal and nutrition-related factors: a systematic review.

The study aimed to evaluate the hypothesis that chewing is a mechanical and physiological contributor to swallowing, physiologic/pathologic processes of the gastrointestinal tract (GIT), and nutrition-related factors. A search strategy was applied to three different databases to investigate if chewing function in adults affects the swallowing, physiologic/pathologic processes of the GIT, and nutrition-related factors compared to controls with no exposure. The included studies were evaluated for methodological quality and risk of bias and certainty of evidence. The results showed 71 eligible studies. Overall, the results showed that 46 studies supported the hypothesis while 25 refuted it. However, the GRADE analysis showed low to very low certainty of the evidence to support the hypothesis that chewing is an important contributor in the swallowing process, and physiologic/pathologic processes in the GIT. The GRADE analysis also showed a moderate to very low certainty of the evidence to suggest that chewing function contributes to nutrition-related parameters. The overall results of the current study showed that a majority (64.7%) of the studies (46 out of 71) supported the hypothesis. However, robust studies with proper design, adequate sample size, and well-defined outcome parameters are needed to establish conclusive evidence.

Poor Oral Health and Esophageal Cancer Risk: A Nationwide Cohort Study.

BACKGROUND: Previous research indicates that poor dental health increases risks for certain types of cancers, including esophageal cancer. This study aimed to investigate the association with esophageal cancer using Swedish Dental Health Register. METHODS: This is a prospective cohort study. The exposures were dental diagnoses classified into healthy, caries, root canal infection, mild inflammation, and periodontitis, as well as number of remaining teeth, at baseline and during multiple visits. The outcome was the incidence of esophageal cancer, which was further divided into esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC). Cox proportional hazards models were used to estimate hazard ratios (HR) and its corresponding confidence intervals (CI). RESULTS: A total of 5,042,303 individuals were included in the study and 1,259 EAC and 758 ESCC cases were identified. Root canal infection at baseline was associated with 41% higher risk for EAC (HR, 1.41; 95% CI, 1.10-1.82), whereas periodontitis at baseline was linked to 32% and 45% higher risks for respective histopathological subtypes (HR for EAC, 1.32; 95% CI, 1.13-1.53; HR for ESCC, 1.45; 95% CI, 1.20-1.75). Fewer remaining teeth at baseline also increased the risks for both histopathological types of esophageal cancer, with a dose-response effect (Ptrend < 0.01). Cox regression analyses with time-varying exposures corroborated the above-mentioned results. CONCLUSIONS: Impaired dental health before cancer diagnosis is associated with excess risks for both histopathological subtypes of esophageal cancer. IMPACT: Our study provided corroborating evidence for the association between poor oral health and esophageal cancer risk.

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.

Validating a model for medication-related dental outcomes in older people.

OBJECTIVES: To externally validate a model for medication-related dental outcomes in (a) a general older population with dementia and (b) a matched population without dementia. SUBJECTS AND METHODS: This validation study used population-based data from seven Swedish national registers (2008-2017). Individuals aged 60+ with dementia were matched to those without dementia on age, gender, and county of residence at the date of diagnosis (index date). The exposure was continuous use of xerogenic medications during the 3-year period before index date. The primary outcome was the number of tooth extraction and restorative procedures within 3 years after index date. RESULTS: A total of 334,220 individuals were included in the final sample. In the dementia cohort, the use of urological drugs (incidence rate ratio [IRR] 1.08, 95% CI 1.03-1.13), respiratory medicines (IRR 1.10, 95% CI 1.04-1.17), and proton-pump inhibitors (IRR 1.09, 95% CI 1.05-1.13) was associated with the primary outcome. In the non-dementia cohort, respiratory medicines (IRR 1.03, CI 1.00-1.05), proton-pump inhibitors (IRR 1.06, CI 1.04-1.08), opioids (IRR 1.05, CI 1.03-1.07), and antidepressants (IRR 1.06, CI 1.04-1.08) were associated with the primary outcome. CONCLUSIONS: Although there were differences in prescription patterns, the model performed similarly in both those with and without dementia.

Cognitive changes and neural correlates after oral rehabilitation procedures in older adults: a protocol for an interventional study.

BACKGROUND: Epidemiological studies show an association between masticatory function and cognitive impairment. This has further strengthened the notion that tooth loss and impaired masticatory function may be risk factors for dementia and cognitive decline. Animal experiments have indicated a causal relationship and several possible mechanisms have been discussed. This evidence is, however, lacking in humans. Therefore, in the current interventional study, we aim to investigate the effect of rehabilitation of masticatory function on cognition in older adults. METHODS: Eighty patients indicated for prosthodontic rehabilitation will be randomly assigned to an experimental or a control group. Participants will conduct neuropsychological assessments, masticatory performance tests, saliva tests, optional magnetic resonance imaging, and answer questionnaires on oral health impact profiles and hospital anxiety and depression scale before, 3 months, and 1 year after oral rehabilitation. The difference between the two groups is that the control group will be tested an additional time, (at an interval of about 3 months) before the onset of the oral rehabilitation procedure. The primary outcome is a change in measures of episodic memory performance. DISCUSSION: Although tooth loss and masticatory function are widespread in older people, it is still an underexplored modifiable risk factor potentially contributing to the development of cognitive impairment. If rehabilitation of masticatory function shows positive effects on the neurocognitive function, this will have great implications on future health care for patients with impaired masticatory status. The present project may provide a new avenue for the prevention of cognitive decline in older individuals. TRIAL REGISTRATION: The protocol for the study was retrospectively registered in ClinicalTrials.gov Identifier: NCT04458207, dated 02-07-2020.

Discontinued dental care attendance among people with dementia: A register-based longitudinal study.

OBJECTIVE: To investigate the factors that increase the risk of discontinuing dental care utilisation after dementia is diagnosed in a population in Stockholm County, Sweden. BACKGROUND: As the progression of dementia results in a deteriorating ability to maintain good oral health, it is important to identify people at risk of discontinued dental care after being diagnosed with dementia. MATERIALS AND METHODS: This study is a register-based longitudinal study. Data were extracted from the Swedish Dementia Registry (SveDem), the Swedish National Patient Register, the Dental Health Register and the Municipal Dental Care Register (Stockholm County Council). The data included people using both general public dental services and care-dependent individuals. Dental visits three years before and after dementia had been diagnosed were analysed. RESULTS: In total, 10 444 people were included in the analysis, of which 19% did not have dental visits recorded after they were diagnosed with dementia. A logistic regression model, adjusted for relevant factors, showed that the factors associated with a greater risk for discontinued dental attendance were fewer remaining teeth (OR = 0.96, 95% CI = 0.95, 0.97) and living alone compared to living with another adult (OR = 1.23, 95% CI = 1.05, 1.43). People with Parkinson's disease dementia had a lower risk (OR = 0.40, 95% CI = 0.19, 0.84) than people with Alzheimer's disease. CONCLUSION: Patients, dental and healthcare personnel, and family members should all be aware of these risk factors so that appropriate support and oral care for people with dementia can be delivered.

Xerogenic Medications as a Predictor for Dental Health Intervention in People with Dementia.

BACKGROUND: Older adults with dementia often have poor oral health. Chronic use of xerogenic medications may contribute to adverse dental outcomes. OBJECTIVE: To investigate the impact of xerogenic medication classes on the predicted risk for dental interventions in people with dementia. METHODS: This was a population-based cohort study involving 30,955 individuals registered in the Swedish Dementia Registry (SveDem) from 2008 to 2015. Data were linked with other national registers. The exposure was xerogenic medication classes used in the three years prior to dementia diagnosis (baseline). The primary outcome was the composite of number of tooth extractions and dental restorations over the three-year follow-up period. Secondary outcomes included the number of tooth extractions and number of dental restorations. Poisson regression models were used to estimate the association between the exposure and outcomes. Analyses were adjusted for age, gender, Mini-Mental State Examination, living arrangement, dementia disorder, average number of medications, Charlson's comorbidity index, number of dental visits, and number of teeth. RESULTS: After adjusting for potential covariates, the use of urological drugs (incidence rate ratio [IRR] 1.16, 95% CI 1.04-1.28), proton pump inhibitors (IRR 1.13, 95% CI 1.04-1.23), and opioids (IRR 1.19, 95% CI 1.06-1.34) were significantly associated with the primary composite outcome. CONCLUSION: The use of specific classes of xerogenic medications was associated with an increased risk for tooth extractions and restorations in people with dementia. The risks and benefits of xerogenic medications, in the context of oral health, should be carefully assessed in this vulnerable population.

Oral health and dental care of older persons-A systematic map of systematic reviews.

OBJECTIVES: To examine the current knowledge on oral health status and dental care of older persons through a systematic mapping of systematic reviews of low or moderate risk of bias. BACKGROUND: Geriatric dentistry covers all aspects of oral health and oral care of older persons. Oral health is part of general health and contributes to a person's physical, psychological and social wellbeing. METHODS: A literature search was performed in three different databases (PubMed, The Cochrane Library and Cinahl) within 12 domains: Dental caries, periodontitis, Orofacial pain and temporomandibular joint (TMJ) pain, mucosal lesions, oral motor function, dry mouth, halitosis, interaction between oral status and other medical conditions, ability to interrelate and communicate, quality of life, ethics and organisation of dental care for older persons. Systematic reviews were identified and scrutinised, highlighting scientific knowledge and knowledge gaps. RESULTS: We included 32 systematic reviews of which 14 were judged to be of low/moderate risk of bias. Most of the domains lack systematic reviews with low or moderate risk of bias. In two of the domains evidence was identified; in institutionalised people aged 65 or older, effective oral hygiene can prevent pneumonia. Furthermore, there is an evidence of a relationship between malnutrition (protein energy-related malnutrition, PEM) and poor appetite and edentulousness. CONCLUSIONS: There is an urgent need for further research and evidence-based knowledge within most domains in geriatric dentistry and in other fields related to oral health and dental care for older persons striving for multi-disciplinary research programmes.

The Effect of Xerostomic Medication on Oral Health in Persons With Dementia.

OBJECTIVES: Medication-induced hyposalivation can increase the risk for oral complications, including dental caries and tooth loss. This problem is particularly important in people with dementia because of their declining ability to maintain oral care. The objective of this study was to describe the association between the number of xerostomic medications used and tooth loss and restorative and dental preventive treatment in a population of persons with dementia. DESIGN: A longitudinal population-based register study with a 3-year follow-up was conducted. Data were extracted from the Swedish Dementia Registry (SveDem), the Swedish Prescribed Drug Register (SPDR), the Swedish National Patient Register (SNPR), and the Dental Health Register (DHR). SETTING AND PARTICIPANTS: Participants were persons with dementia who were registered in the SveDem at the time of their dementia diagnosis. MEASURES: The exposure was continuous use of xerostomic medications over the 3 years prior to dementia diagnosis (baseline). The outcomes were the incidence of tooth extractions, tooth restorations, and dental preventive procedures. Poisson regression models were used to estimate incidence rate ratios (IRRs) for the association between the exposure and outcomes, adjusting for relevant confounders. RESULTS: A total of 34,037 persons were included in the analysis. A dose-response relationship between the exposure and tooth extractions was observed. Compared with nonusers of xerostomic medication, the rate of tooth extractions increased with increasing number of xerostomic medications used (IRR = 1.03, 1.11, and 1.40 for persons using an average >0-1, >1-3, and >3 xerostomic medications, respectively). However, the risk for having new dental restorations and receiving preventive procedures did not differ between groups. CONCLUSION: Continuous use of xerostomic medications can increase the risk for tooth extraction in people with dementia. This study highlights the importance of careful consideration when prescribing xerostomic medications to people with dementia, and the need for regular and ongoing dental care.

Medications That Cause Dry Mouth As an Adverse Effect in Older People: A Systematic Review and Metaanalysis.

OBJECTIVES: To assess and quantify the risk of drug-induced dry mouth as a side effect in older people. DESIGN: Systematic review and metaanalysis. SETTING: A search of the literature was undertaken using Medline, Embase, Cochrane, Web of Science, and PubMed from 1990 to 2016. PARTICIPANTS: Older people (aged ≥60) who participated in intervention or observational studies investigating drug use as an exposure and xerostomia or salivary gland hypofunction as adverse drug outcomes. MEASUREMENTS: Two pairs of authors screened titles and abstracts of studies for relevance. Two authors independently extracted data, including study characteristics, definitions of exposure and outcome, and methodological quality. For the metaanalyses, random-effects models were used for pooling the data and I2 statistics for exploring heterogeneity. RESULTS: Of 1,544 potentially relevant studies, 52 were deemed eligible for inclusion in the final review and 26 in metaanalyses. The majority of studies were of moderate methodological quality. In the intervention studies, urological medications (odds ratio (OR) = 5.91, 95% confidence interval (CI) = 4.04-8.63; I2  = 62%), antidepressants (OR = 4.74, 95% CI = 2.69-8.32, I2  = 21%), and psycholeptics (OR = 2.59, 95% CI = 1.79-3.95, I2  = 0%) were significantly associated with dry mouth. In the observational studies, numbers of medications and several medication classes were significantly associated with xerostomia and salivary gland hypofunction. CONCLUSION: Medication use was significantly associated with xerostomia and salivary gland hypofunction in older adults. The risk of dry mouth was greatest for drugs used for urinary incontinence. Future research should develop a risk score for medication-induced dry mouth to assist with prescribing and medication management.

Dental care utilization in patients with different types of dementia: A longitudinal nationwide study of 58,037 individuals.

INTRODUCTION: Dementia may be associated with discontinuation of regular dental checkups, which in turn results in poorer oral health. METHODS: We investigated the trend of change in dental care utilization and the number of teeth before and after being diagnosed with dementia. Longitudinal cognitive- and dental health-related information were merged using data on 58,037 newly diagnosed individuals from the Swedish Dementia Registry and Swedish Dental Health Register during 2007 to 2015. RESULTS: Following dementia diagnosis, rate of dental care visits significantly declined. Individuals with mixed dementia, dementia with parkinsonism, and those with more severe and faster cognitive impairment had significantly higher rate of decline in dental care utilization. Vascular dementia and lower baseline Mini-Mental State Examination score were significant predictors of faster loss of teeth. DISCUSSION: Dental care utilization markedly declines following dementia diagnosis. The reduction is more prominent in those with rapid progressive cognitive impairment and the ones with extra frailty burden.

Consumption and direct costs of dental care for patients with head and neck cancer: A 16-year cohort study.

Patients with head and neck (H&N) cancer are commonly treated with surgery and/or radiotherapy, which can increase the risk of oral infection, dental caries, and periodontal disease. The present study investigated dental care consumption and costs in patient with H&N cancer before and after the cancer diagnosis. Data from Swedish regional and national registers were used to follow up dental care utilization and dental procedure costs. The analysis included 2,754 patients who had been diagnosed with H&N cancer (exposed cohort) in Stockholm County, Sweden, during 2000-2012 and 13,036 matched persons without cancer (unexposed cohort). The exposed cohort was sub-grouped into irradiated and non-irradiated patients for analysis. The exposed cohort underwent a moderately higher number of dental procedures per year than the unexposed cohort in both the year of the cancer diagnosis and the year after cancer diagnosis; in addition, these numbers were higher in the irradiated than in the non-irradiated subgroup of the exposed cohort. Dental care consumption and costs in the exposed cohort declined over time but remained at a slightly higher level than in the unexposed cohort over the long term (more than two years). Examinations and preventive procedures accounted for most of the higher consumption in the short term (2 years) and at the longer term follow-up. Swedish national insurance subsidized costs for dental treatment, which were highest in the irradiated subgroup and lowest in the unexposed cohort. Direct costs to the patient, however, were similar among the groups. Swedish national health insurance protects patients with H&N cancer from high dental expenditures. Further studies on the cost-effectiveness of preventive dental care for patients are needed.

Natural fluoride in drinking water and myocardial infarction: A cohort study in Sweden.

Large geographical variation in the coronary heart disease (CHD) incidence is seen worldwide and only a part of this difference is attributed to the classic risk factors. Several environmental factors, such as trace elements in the drinking water have been implicated in the pathogenesis of CHD. The objective was to assess the association between drinking water fluoride exposure and myocardial infarction in Sweden using nationwide registers. This large cohort consisted of 455,619 individuals, born in Sweden between January 1, 1900 and December 31, 1919, alive and living in their municipality of birth at the time of start of follow-up. Estimated individual drinking water fluoride exposure was stratified into four categories: very low (<0.3mg/l), low (0.3-<0.7mg/l), medium (0.7-<1.5mg/l) and high (≥1.5mg/l). In Cox regression analyses, compared to the very low fluoride group, the adjusted Hazard Ratio for the low fluoride group was 0.99 (95% confidence interval, 0.98-1.00), for the medium fluoride group 1.01 (95% confidence interval, 0.99-1.03) and 0.98 (95% confidence interval, 0.96-1.01) for the highest fluoride group. Adding water hardness to the model did not change the results. We conclude that the investigated levels of natural drinking water fluoride content does not appear to be associated with myocardial infarction, nor related to the geographic myocardial infarction risk variation in Sweden. Potential misclassification of exposure and unmeasured confounding may have influenced the results.

Neurological disease or intellectual disability among sons of female Swedish dental personnel.

OBJECTIVE: Prenatal exposure to elemental mercury may be a potential hazard for the offspring of female dental personnel working with dental amalgam. The aim of this study was to investigate whether potential in utero exposure to mercury might have affected the development of nervous system of the sons of Swedish female dental personnel leading to an increased risk of neurological disease or intellectual disability. MATERIAL AND METHODS: We used national Swedish registers to investigate risks for diseases potentially related to adverse effects on neurodevelopment. Sons of female dentists (n=1690) and dental nurses (n=10,420) were compared with cohorts consisting of sons of other female healthcare personnel. Due to changes in mercury exposure in dentistry during the study period, analyses were stratified by decade of birth. Hazard ratios (HRs) were calculated using Cox proportional hazard models. RESULTS: We found no elevated risk for neurological disease, epilepsy or intellectual disability among the sons of dental personnel during any of the decades studied. HRs for neurological disease among the dental nurse cohort were even below 1.00 during the 1970s and 1980s. A low number of events resulted in uncertainty regarding results in the dentist cohort. CONCLUSIONS: We did not find any support for the hypothesis that mercury exposure in Swedish dentistry during the 1960s, 1970s or 1980s had any effect on the incidence of neurological disease or intellectual disability among the sons of female dental personnel. Our results imply that current use of dental amalgam should not represent an elevated risk for neurological disease or intellectual disability among the offspring of dental personnel.

Longevity of posterior resin composite restorations in adults ­ A systematic review.

OBJECTIVE: To conduct a systematic review of the literature on the longevity of posterior resin composite restorations in adults. MATERIAL AND METHODS: A systematic literature search was conducted according to pre-determined criteria for inclusion and exclusion. The studies selected were prospective clinical trials with a minimum follow-up time of 4 years, 40 restorations per experimental group and an annual attrition rate of less than 5%. Initially, abstracts and full-text articles were assessed independently and the assessment was subsequently agreed on by five reviewers. The methodological quality of the studies was assessed according to the Swedish Council on Health Technology Assessment (SBU) standard checklist for determining the extent to which studies meet basic quality criteria. RESULTS: In all, the literature search identified 4275 abstracts and 93 articles were read in full-text. There were eighteen studies which met the criteria for inclusion, eight of which were included in the analysis. There were 80 failures of restorations with a total follow-up time at risk for failure of 62,030 months. The overall incidence rate for all causes of failure was 1.55 lost restorations per 100 restoration years. The most common biological reason for failure (a total of 31 restorations) was secondary caries, with or without fracture of the restoration. The quality of the evidence was low. CONCLUSIONS: In an efficacy setting, the overall survival proportion of posterior resin composite restorations is high. The major reasons for failure are secondary caries and restoration fracture which supports the importance of adequate follow-up time. CLINICAL SIGNIFICANCE: The overall survival proportion of posterior composite restorations was high, but the results cannot be extrapolated to an effectiveness setting. The importance of adequate follow-up time is supported by the finding that secondary caries often occurred after 3 years or later.