Polymer-based dental filling materials placed during pregnancy and risk to the foetus.

BACKGROUND: Tooth-coloured polymer-based dental filling materials are currently the first choice for dental restorative treatment in many countries. However, there are some concerns about their safety. It has been shown that substances known as endocrine disrupters, which might pass through the placental barrier, are released from these materials within the first hours after curing. Thus, the placement of polymer-based dental fillings in pregnant women may put the vulnerable foetus at risk. Large epidemiological studies exploring the risk of having polymer-based dental materials placed during pregnancy are lacking. The aim of this study was to investigate the association between the placement of polymer-based dental fillings during pregnancy and adverse birth outcomes. METHODS: This study is based on data from the large Norwegian Mother and Child Cohort Study (MoBa). The information about dental treatment during pregnancy was obtained from questionnaires sent to the participating women during weeks 17 and 30 of pregnancy. Reported placement of "white fillings" was used as exposure marker for having received polymer-based dental filling materials. Only singleton births were included in the present study. Data were linked to the Medical Birth Registry of Norway. Logistic regression models that included the mother's age, level of education, body mass index, parity, and smoking and alcohol consumption during pregnancy were used to estimate the odds ratio (OR) and 95% confidence interval (CI). Different adverse birth outcomes were of interest in the present study. RESULTS: Valid data were available from 90,886 pregnancies. Dentist consultation during pregnancy was reported by 33,727 women, 10,972 of whom had white fillings placed. The adjusted logistic regression models showed no statistically significant association between having white dental fillings placed during pregnancy and stillbirth, malformations, preterm births, and low or high birth weight. CONCLUSIONS: In this study, women who reported white fillings placed during pregnancy had no increased risk for adverse birth outcomes compared with women who did not consult a dentist during pregnancy. Thus, our findings do not support the hypothesis of an association between placement of polymer-based fillings during pregnancy and adverse birth outcomes.

Prenatal exposure to dental amalgam and pregnancy outcome.

OBJECTIVE: Questions have been raised about potential risks of prenatal exposure to mercury from amalgam fillings during pregnancy. The aim of this study was to assess possible associations between exposure to amalgam fillings in pregnant women participating in a large cohort study and adverse pregnancy outcome. METHODS: In the Norwegian Mother and Child Cohort Study (MoBa), a valid information about the number of teeth with amalgam fillings and dental treatment, including new amalgam fillings placed or removed during pregnancy, was available from 69 474 pregnancies. The information was obtained from two questionnaires sent to the women at 17 and 30 weeks of pregnancy, and the data were linked to the Medical Birth Registry of Norway. Logistic regression was used to estimate the odds ratio (OR) and 95% confidence intervals (95% CI) as a measure of association between pregnancy outcome and prenatal exposure to amalgam fillings. RESULTS: Logistic regression models, including mothers' age, education, BMI, parity, smoking during pregnancy, and alcohol consumption during pregnancy revealed no significant associations between the number of teeth with amalgam fillings and early preterm delivery, late preterm delivery, low birthweight, malformation or stillbirth. CONCLUSIONS: We found no evidence for serious perinatal consequences of maternal exposure to amalgam fillings during pregnancy.

Characterization of health complaints before and after removal of amalgam fillings--3-year follow-up.

OBJECTIVE: Some patients attribute health complaints to amalgam fillings and report improvement of health after replacement of amalgam fillings. The aim of the present study was to characterize the changes of different health complaints after replacement of amalgam fillings and compare with an external reference group from the general population. MATERIALS AND METHODS: The study group included 20 patients with health complaints attributed to amalgam fillings who were participants in the treatment group of a clinical trial at the Norwegian Dental Biomaterials Adverse Reaction Unit. The patients were asked to indicate the intensity of local and general health complaints on numeric rating scales (0-10) before removal of amalgam fillings and at follow-up 3 years after removal. Data from the patient group were compared with data from an external reference group (n = 441). RESULTS: Before treatment the mean intensity of complaints were on a higher level in the treatment group compared to the reference group. The most frequently reported complaints in the treatment group were gastrointestinal symptoms, fatigue, pain from muscles and joints, symptoms from ear/nose/throat and difficulty concentrating. From pre-treatment examination to the 3-year follow-up 20 of 23 health complaints decreased, being statistically significant for taste disturbances, pain from muscles and joints, gastrointestinal complaints, complaints from ear/nose/throat and fatigue. CONCLUSIONS: The inter-individual variation of intensities of health complaints was considerable and the reduction of health complaints varied for the different complaints. Several factors may be of importance for the observed reduction of complaint intensity.

A biobank of primary teeth within the Norwegian Mother and Child Cohort Study (MoBa): a resource for the future.

The Norwegian Mother and Child Cohort Study (MoBa) is a prospective population-based cohort study including >100 000 pregnancies and following the children through childhood, using questionnaires and collecting biological samples. The aim of MoBa is to test specific aetiological hypotheses by estimating the association between exposure and disease, aiming at prevention. A biobank for exfoliated primary teeth collected from the children participating in MoBa has been established (MoBaTooth Biobank). Samples of tooth tissues from the primary dentition can give information about exposure to toxic and essential elements during fetal life and early infancy. Prenatally and postnatally formed tooth tissues permanently document early exposures unlike other biomarkers, as teeth form incrementally at a known rate. Results from tooth analyses will be coupled with corresponding information in the multiple questionnaires and data from analysis of other biological samples collected by MoBa. Invitations to donate one or more teeth are sent to all mothers/children in the period 2008-2016, when the child is 6.75 years old. By August 2011, 7400 participants had been recorded into the MoBaTooth database donating altogether 9798 teeth (1.3 teeth per child). The response rate was 24%, but there is a lag of >1 year in the response. Data from the tooth biobank can supply MoBa with important additional information on the uptake of trace elements during fetal life and early infancy. This information can illuminate possible causal factors of health and disease in the future.

Exposure to dental amalgam restorations in pregnant women.

OBJECTIVES: The Norwegian Mother and Child Cohort Study (MoBa) started in 1999 to identify environmental factors that could be involved in mechanisms leading to disease. Questions have been raised about potential risks to the fetus from prenatal exposure to mercury from amalgam fillings in pregnant women. The aim of the present study was to identify factors potentially associated with amalgam fillings in pregnant women participating in the Norwegian Mother and Child Cohort Study (MoBa). An additional aim was to obtain information about dental treatment in the cohort. METHODS: Total of 67,355 pregnancies from the MoBa study were included in the present study. Information regarding age, education, smoking habits, alcohol consumption, weight, and height for the women was obtained from a questionnaire that was filled in at the 17th week of pregnancy. In another questionnaire, which was sent to all participants in the 30th week of pregnancy, the women reported types of dental treatment during pregnancy, total number of teeth, and number of teeth with amalgam fillings. The self-assessed number of teeth and number of teeth with amalgam fillings were validated in an external sample of 97 women of childbearing age. RESULTS: Odds ratio for having more than 12 teeth with amalgam fillings increased considerably with age. Other significant risk factors for having high exposure to amalgam were low education, high body mass index (BMI), and smoking during pregnancy. Women with the lowest levels of education had a twofold increased odds ratio of having more than 12 teeth filled with amalgam compared with women who had more than 4 years of university studies. According to the results from the validation of self-assessed number of teeth with amalgam fillings, the information obtained was reliable. CONCLUSION: Age, education, smoking habits, and BMI were associated with amalgam exposure.

[Health complaints related to dental filling materials]. / Pasienter med helseplager relatert til tannfyllinger.

BACKGROUND: A wide range of materials is used in dental treatment. To what extent these materials lead to adverse reactions is under dispute. The aim of this study was to investigate whether patients with suspected adverse reactions to dental materials experienced an improvement in health after these materials were replaced. MATERIAL AND METHODS: Information on health complaints related to dental materials was obtained from the Dental Biomaterials Adverse Reaction Unit in Bergen, Norway for 142 patients. A follow-up questionnaire regarding subjective health was sent to these patients 1(1/2) to 2(1/2) years later. A similar questionnaire was sent to a reference group of 800 persons drawn from the general population. RESULTS: The patient group had more health complaints than the reference group (p < 0.001) at baseline. Of the 84 patients who completed the questionnaire (59%) 35 had changed dental materials. Amalgam fillings had been replaced in most of these patients. 23 patients (66%) reported improved health after replacement. Intraoral complaints decreased significantly (p = 0.022), and were most pronounced in patients with lesions in contact with dental materials. The intensity of various health complaints decreased slightly in most patients with replaced dental materials, but the patient group still had significantly higher health complaint indices than the reference group. INTERPRETATION: The intensity of subjective health complaints was reduced after replacement of dental materials, but it was still higher than for a comparable group in the general population. The results indicate that there may be a specific health effect of replacing dental materials, but normal symptom fluctuations over time and placebo effects such as positive effects from expectations and general care from the health personnel may have had an influence.

A follow-up study of patients with subjective symptoms related to dental materials.

OBJECTIVES: The extent to which substances released from dental materials cause adverse health effects and whether removal of dental materials results in improvement of health is a matter of dispute. The aim of the study was to investigate changes in the intensity of subjective symptoms after replacement of dental materials in patients referred for adverse reactions related to dental materials, and to compare the profiles of symptoms with those found in the general population. METHODS: Information was obtained from 142 patients referred to the Dental Biomaterials Adverse Reaction Unit in Bergen, Norway. At the time of examination, all patients completed a questionnaire regarding a range of subjective symptoms. A follow-up questionnaire was sent to all patients 1 to 2 years later. Similar questionnaires were sent to a reference group of 800 persons drawn from the general population. RESULTS: The follow-up questionnaires were completed and returned by 84 patients, and 441 persons in the reference group. The patient group presented higher symptom indices than the reference group (P<0.001). Generally, there was some decrease in the intensity of different symptoms in patients who had replaced dental materials. The decrease was evident regarding intraoral symptoms (P=0.022) and total symptom index (P=0.041). The group of patients who had replaced materials still had significantly higher symptom indices than those of the reference group. Patients who had not replaced dental materials did not present any reduction in symptom indices. CONCLUSION: The pattern of symptoms was similar for the groups investigated. At the group level, the intensity of local and some general subjective symptoms was reduced after replacement of the materials, but not to the level found in the general population.

Four years of clinical experience with an adverse reaction unit for dental biomaterials.

OBJECTIVES: We describe the function of, and results from, the Norwegian National Dental Biomaterials Adverse Reaction Unit after 4 years of activity from 1993 to 1997. METHODS: During this period of time, 296 patients were examined at the unit, which is located at the Dental School, University of Bergen. The most prevalent age group was 40-49 years, and 70% were women. Dental amalgam was the primary reason for referral to the unit for nearly 85% of the patients, followed by metals in crowns and bridges (11%). Materials in removable dentures, resin-based filling materials and cements, endodontic materials, and others, including temporary materials, were also involved. Nearly all (96%) patients reported general subjective symptoms, such as muscle and joint pain, fatigue, and memory problems. Complaints involving the orofacial region (lips, face, temporomandibular joint) and intraoral subjective symptoms were also common. RESULTS: Of the patients who were patch tested with substances in dental materials, 23% were positive to gold, 28% to nickel, 14% to cobalt, 9% to palladium, 6% to mercury, and 8% to one or more components of resin-based materials. Mercury concentrations in blood and urine were statistically higher in the patients with amalgam fillings compared with those without. CONCLUSIONS: Generally, we could not establish a straightforward cause-and-effect relationship between the presence of dental biomaterials and general symptoms. Twenty patients were advised to replace restorative materials because of contact lesions. Another 20 patients were recommended replacement of materials because of allergy verified with positive patch tests. The complex nature of most of the reactions requires a multidisciplinary approach to the care taking of patients who are concerned about reactions from dental materials, particularly amalgam.

Patients' choice of dental treatment following examination at a specialty unit for adverse reactions to dental materials.

The Dental Biomaterials Adverse Reaction Unit in Bergen, Norway, is a national unit for the examination of patients with suspected adverse reactions to dental materials. The aim of this study was to investigate whether patients with suspected adverse reactions to dental materials experienced improvement in health after dental restorations had been replaced, and whether they had acted according to the recommendations of the Unit. A questionnaire was sent to 358 patients who had been examined at the Unit 18 months to 7 years earlier. Of the 207 patients who completed the questionnaire, 85 had had restorative materials replaced with other types of materials. A majority had had amalgam fillings replaced. After replacement, 51 patients reported an improvement in health. Twelve patients reported that they felt worse after replacement. The Unit recommended replacement of materials in 31 patients, of whom 24 followed the recommendation. Among 176 patients who were not given specific recommendations as to replacement of dental materials, 67 had had their restorations replaced, and 40 had started to have them replaced. It appears that the examination at the Dental Biomaterials Adverse Reaction Unit is one of several inputs that influence a person's decision to replace dental materials.

Reporting on adverse reactions to dental materials--intraoral observations at a clinical follow-up.

OBJECTIVES: A national reporting system designed to monitor adverse reactions to dental materials was established in Norway in 1993. The activities have also included clinical examination of patients with suspected reactions to dental materials. The ongoing activities are coordinated by the Dental Biomaterials Adverse Reaction Unit at the University of Bergen. The reporting procedure is based on voluntary spontaneous reporting by dentists and physicians. The reports could be based on subjective symptoms or objective findings, or both. The aim of the present study was to compare reported objective intraoral findings with those found during examination at the unit. METHODS: Reported reactions were compared with clinical findings obtained following dental and medical examination at the unit. From 1993 to 1999, a total of 899 reports were received while 253 patients were referred and examined at the unit. RESULTS: The reports on patients who were examined at the unit involved mainly reactions related to amalgam fillings (84%), metals in fixed dentures (11%), resin-based materials and cements (4%), materials used in removable dentures (2%), and endodontic materials (2%). Edema, lichenoid reactions, ulcers/vesicles, erythema, and atrophy were found in 80 patients during the examination at the unit. For 35 of these patients, the intraoral findings at the unit were also given in the reports. For another 45 patients, objective intraoral signs of reactions were found upon examination at the unit, but these findings had not been reported. CONCLUSION: A spontaneous reporting system is a cost-effective method for monitoring intraoral reactions associated with dental materials. Considering the increasing number and complexity of these materials, there appears to be a need for continuous validation of reports by a speciality unit. In order to receive more accurate information about the adverse reactions, it would be advisable that the reporting forms include more detailed guidance regarding signs of reactions that practitioners should be on the look out for and consider.

Personality variables in patients with self-reported reactions to dental amalgam.

Personality variables in persons with self-reported reactions to dental amalgam (amalgam patients, n = 26, 17 F, 9 M) and in others without such symptoms (controls, n = 21, 14 F, 7 M) are compared. The groups were comparable regarding age, education, and amount of amalgam. Minnesota Multiphasic Personality Inventory-2 (MMPI-2) profiles were obtained for all subjects. On MMPI-2, the amalgam patients presented a 'conversion V' pattern, and elevated psychasthenia and schizophrenia scales, reflecting an increased prevalence of psychological and somatic complaints compared with the controls. This indicates that amalgam patients experience ill health, as their personality profiles bear several similarities with other groups with long-lasting symptoms.