Adverse reactions to dental biomaterials: Experiences from a specialty clinic.

OBJECTIVES: The Dental Biomaterials Adverse Reaction Unit was initiated by the Norwegian health authorities in 1992 as a response to the public concern regarding the safety of dental amalgam and other dental materials. In this paper, experiences from the Unit are briefly summarized. METHODS: The Norwegian health authorities' strategy included four main topics: (i) development of a manufacturer-independent system for monitoring adverse reactions related to dental materials, (ii) funding of a specialty unit for clinical examinations of referred patients, (iii) development of official guidelines for examination and treatment of patients with health complaints attributed to dental materials, and (iv) funding of an experimental treatment project for patients with health complaints attributed to dental amalgam. RESULTS: From the start, more than 2700 adverse reaction reports were received. In the initial years, amalgam was the most frequent material mentioned in the reports. Reports about polymer-based composite materials have not increased after the prohibition of amalgam in Norway. Clinical examination of referred patients is complex and time consuming, and it is important to consider differential diagnoses. There are methodological challenges associated with the design of experimental treatments used on patients with adverse reactions attributed to dental materials. However, the results from the treatment project indicate lower symptom load after replacement of amalgam with other dental restorative materials. SIGNIFICANCE: Producer independent adverse reaction reporting can provide valuable information about the safety of these materials and could serve as a complement to the mandatory reporting system described in the European medical device regulations (MDR).

Estimated mercury vapor exposure from amalgams among American pregnant women.

This study examined the impact of mercury (Hg) vapor exposure from amalgams among all American pregnant women. Amalgam-Hg vapor exposure among 1,665,890 weighted-pregnant women (n = 37) was examined in the 2015-2020 National Health and Nutrition Examination Survey (NHANES). Correlation coefficients between amalgam surfaces and daily micrograms (µg) of urinary Hg excretion and daily µg of Hg vapor exposure from amalgams per kilogram (Kg) bodyweight were calculated. Daily Hg vapor exposure from amalgams was compared to Hg vapor safety limits. About 600,000 pregnant women (∼36%) had at least one amalgam surface. Median daily urinary Hg excretion was ∼2.5-fold higher among pregnant women with amalgams as compared to pregnant women without amalgams. A significant correlation was observed between the number of amalgam surfaces and daily urinary Hg excretion. Among pregnant women with amalgams, it was estimated that the median daily Hg vapor dose from amalgams was 7.66 µg of Hg and 0.073 µg of Hg/Kg bodyweight. Among all pregnant women, ∼28% received daily Hg vapor doses from amalgams above the least restrictive United States (US) Environmental Protection Agency (EPA) safety limit and ∼36% received above the most restrictive California (CA) EPA safety limit. Given the potential for fetal toxicological effects from prenatal Hg vapor exposure, special emphasis needs to be placed on reducing/eliminating amalgams in pregnancy/women of reproductive age and future studies should evaluate adverse pregnancy outcomes.

Which caries removal method to select?

DATA SOURCES: Searches were carried out using PubMed/MEDLINE and Web of Science databases between January 2008 and January 2023. Only articles in English language were included. Boolean operators were used to search: "permanent teeth" OR "permanent tooth" OR "permanent dentition" AND "deep caries" OR "stepwise" AND "partial caries removal OR "stepwise caries removal" OR "pulp vitality" OR "healing rate". STUDY SELECTION: Inclusion criteria were randomised controlled trials, which compared the total removal of carious tissue with either a selective or stepwise removal in permanent teeth with deep carious lesions. Criteria also required a follow up of at least 6 months and publications in English. Exclusion criteria were articles in other languages, articles not comparing different types of total or selective caries removal and articles published before January 2008. DATA EXTRACTION AND SYNTHESIS: Data extraction followed PRISMA guidelines. Two reviewers independently screened articles, analysing titles and abstracts using Rayyan's Intelligent Systematic Review Platform. They also collected data and risk of bias assessed using the Cochrane Risk of Bias Tool for Randomised Trials, dividing articles into high risk of bias, few concerns and low risk of bias. A third researcher resolved conflict or doubt in case of divided opinions. RESULTS: In total, 105 articles were identified, and 10 duplicates removed. 95 articles were reviewed by title and abstract and 75 of these did not meet the inclusion criteria. 20 articles were then read, excluding a further 15 due to comparing only partial removal or non-selective caries removal or absence of numerical data. This left 5 articles which met eligibility criteria. These were randomised controlled trials between 2010 and 2021. Follow up ranged from 1 month to 5 years. The inclusion and exclusion criteria in all studies had similar clinical parameters. 3 studies performed management only on permanent molars, whilst the rest also included management on permanent incisors/canines/premolars and molars. Management of caries was divided into non-selective caries removal vs partial caries removal (either selective or stepwise). All but 2 studies included specific information about the materials used. Liners were calcium hydroxide or Dycal, provisional restorations were glass ionomer cements or Ketax Molar and definitive restorations were Herculite Tetric N-Ceram resin, Ivolclar Vivadent or amalgam. Clinical success or failure was measured using pulp vitality, absence of periapical lesions, radiographic analysis and lack of symptoms. Clinical follow up was evaluated by external examiners, although 2 studies did not specify this clearly. There were a variety of tools used for statistical analysis in each study. CONCLUSIONS: When comparing non-selective caries removal with either selective or stepwise, 3 studies proposed statistically significant differences in terms of longevity, marginal integrity and success rate of restorations. 1 study stated inexistence of statistically relevant divergences between procedures. Non-selective caries removal is not highly recommended for deep carious lesions and may be considered invasive and risks pulpal exposure. Both selective and stepwise removal are considered conservative approaches. Selective removal is considered the best management option in the short term (with 1.5 years follow up), predominantly related to a lower risk of pulpal exposure. At 5 years, however, the results of selective were similar to those of non-selective, accepting the null hypothesis. There were also no differences in success rates for materials used for definitive restorations.

Mast cells in oral lichen planus and oral lichenoid lesions related to dental amalgam contact.

The aim of this study was to analyze the expression of mast cell markers toluidine blue, c-kit, and tryptase and presence of mononuclear inflammatory cells in oral lichen planus (OLP) and oral lichenoid lesions related to dental amalgam. Nineteen specimens of OLP, OLLC, and healthy oral mucosa were selected. Mononuclear inflammatory cells were analyzed. Histochemical and immunohistochemical analyses were performed using toluidine blue, anti-c-kit and anti-tryptase reagents, and the results were quantified in areas A and B of connective tissue. Mast cells of all OLP and OLLC samples were positive for toluidine blue, c-kit, and tryptase. The density of toluidine blue+, c-kit+ and tryptase+ mast cells was higher in tissue with OLP and OLLC compared with healthy controls (p < 0.05). No difference was noted in mast cells density between OLP and OLLC (p > 0.05). The density of tryptase+ mast cells was higher in the subepithelial region (area A) than the region below it (Area B) in OLLC (p = 0.047). The mononuclear inflammatory cell density was higher in OLLC compared to OLP, but without statistical significance (p > 0.05). A positive statistical correlation was found between mononuclear immune cells and density of c-kit+ and tryptase+ mast cells in OLP (r = 0.943 and r = 0.886, respectively). Our data demonstrate that the etiopathogenesis process of OLP and OLLC modulates the expansion and degranulation of mast cells; mast cells density, however, was similar between OLP and OLLC. The distribution of mast cells appears to vary along the lamina propria.

Effect of composite resin containing antibacterial filler on sugar-induced pH drop caused by whole saliva bacteria.

STATEMENT OF PROBLEM: Secondary caries around restorations is a major problem and can be attributed to bacteria invading microgaps formed at the tooth-restoration interface. An antibacterial composite resin containing quaternary ammonium silica (QASi) filler has been reported to inhibit enamel demineralization in situ. However, whether the prevention of enamel demineralization by QASi-containing composite resin is because of the reduced metabolic activity of acid-producing saliva bacteria is unclear. PURPOSE: The purpose of this study was to compare the effects of QASi-containing composite resin and 2 other restorative materials on the viability of salivary bacteria and sugar-induced acid production. MATERIAL AND METHODS: Whole saliva from each of the 30 study participants, 14 at high risk and 16 at low risk for caries, was brought into contact with quadruplicate specimens of 3 restorative materials, Infinix Flowable Composite, an anti-bacterial composite resin containing 1.5% QASi filler (Nobio), Filtek Supreme Flowable Restorative (3M), a conventional flowable composite resin, and dental amalgam (Silmet). Bacterial growth and sugar-induced acid production on each restorative material were measured every 20 minutes for 18 hours. Caries risk groups were compared using the t test and repeated measures analysis of variance (α=.05). When significant, Bonferroni multiple comparisons were used. RESULTS: On average, the saliva with the QASi-containing composite resin specimens maintained a near-neutral pH, not dropping below pH 6.0. The saliva associated with both conventional restorative materials exhibited a pH drop below 5.5 (P<.001), the critical threshold for tooth demineralization according to the Stephan curve. Virtually no growth was measured on the surface of the antibacterial composite resin, whereas bacteria grew on the conventional composite resin and dental amalgam (P<.001). No differences were observed between participants at high and low risk of caries. CONCLUSIONS: Unlike amalgam and conventional composite resin, the QASi-containing composite resin showed a near-complete shutdown of the metabolic activity of salivary bacteria upon contact and virtually no bacterial viability. This suggests that the prevention of tooth demineralization by QASi-containing restoratives is associated with a significant reduction in bacterial metabolic activity.

The preventive effect of glass ionomer cement restorations on secondary caries formation: A systematic review and meta-analysis.

OBJECTIVE: The objective is to compare the preventive effect on secondary caries of glass ionomer cement (GIC) restorations with amalgam or resin-composite restorations. METHODS: Two independent researchers conducted a systematic search of English publications in PubMed, Web of Science, Cochrane and Scopus. They selected randomized clinical trials comparing secondary caries incidences around GIC restorations (conventional GIC or resin-modified GIC) with amalgam or resin-composite restorations. Meta-analysis of the secondary-caries incidences with risk ratio (RR) and 95% confidence interval (95% CI) as the effect measure was performed. RESULTS: This review included 64 studies. These studies included 8310 GIC restorations and 5857 amalgam or resin-composite restorations with a follow-up period from 1 to 10 years. Twenty-one studies with 4807 restorations on primary teeth and thirty-eight studies with 4885 restorations on permanent teeth were eligible for meta-analysis. The GIC restorations had a lower secondary caries incidence compared with amalgam restorations in both primary dentition [RR= 0.55, 95% CI:0.41-0.72] and permanent dentition [RR= 0.20, 95% CI:0.11-0.38]. GIC restorations showed similar secondary caries incidence compared with resin-composite restorations in primary dentition [RR= 0.92, 95% CI:0.77-1.10] and permanent dentition [RR= 0.77, 95% CI:0.39-1.51]. Conventional GIC restorations showed similar secondary caries incidence compared with resin-modified GIC-restored teeth in both primary dentition [RR= 1.12, 95% CI:0.67-1.87] and permanent dentition [RR= 1.63, 95% CI:0.34-7.84]. CONCLUSIONS: GIC restorations showed a superior preventive effect against secondary caries compared to amalgam restorations, and a similar preventive effect against secondary caries compared to resin-composite restorations in both primary and permanent teeth. [PROSPERO Registration ID: CRD42022380959].

Dental amalgam teaching phase-out - a step too soon? Foundation trainees' experience of amalgam use in dental school compared to practice: a mixed-methods survey.

Aim This study aimed to explore disparities in experience of UK dental foundation trainees in amalgam use at dental school compared to their first year in dental practice.Methods A modified version of the 'survey of Yorkshire dentists' targeted the dental foundation trainees. A mixed-method of quantitative and thematic content analysis was undertaken for the close-ended and free-text responses, respectively.Results Only 35% of participants described their confidence level as 'satisfactory' in placing dental amalgam before starting their dental foundation training and 51% scored the level of teaching between 'very poor' and 'satisfactory'. In total, 63% of respondents were in favour of receiving additional support in placing amalgam restorations during their undergraduate training. Participants indicated that the consequences of amalgam phase-out are increased appointment times and decreased quality of care due to patient and health service unaffordability of amalgam alternatives.Conclusion These findings raise concerns regarding newly qualified undergraduates' confidence, experience and skill in placing amalgams. This suggests the need to increase undergraduate education and training to improve undergraduates' skills and confidence in amalgam procedures to reduce the gap between the dental schools and real-world practice.

Amalgam or composite in pediatric dentistry: Analysis of private insurance claims data.

BACKGROUND: Advancements in dental materials and changing parental preferences are modifying the frequency of use of restorative materials. This insurance claims analysis examined the trends in the use of amalgam and resin composite in the United States. METHODS: Commercial dental insurance claims were analyzed to compare 505,994 restorations, corresponding with procedure codes for 1-, 2-, and 3-surface amalgam or resin restorations. Paid claims collected nationwide from January 2010 through March 2020 were analyzed. Data for children aged 3 through 12 years were used, resulting in 219,632 unique patient identification numbers. Generalized estimating equation models applied to logistic regression were used. All tests were conducted using a 2-sided 5% significance level. RESULTS: In general, girls were less likely to receive amalgam than boys. A $20,000 increase in median household income was associated with a 16% decrease in the odds of amalgam being placed. Pediatric dentists (performing 15.1% of all restorations) were not as likely as general dentists (18.4%) to use amalgam. Having more surfaces in a restoration was associated with higher probability of amalgam placement. The percentage of amalgam restorations was higher for 2010 (26.9%) than for 2011 through 2020, and this pattern recurred in several of the years analyzed. Generally, patient age at time of amalgam restoration increased over time. CONCLUSION: The use of amalgam is trending down; the sharpest decline was noted in 2014. Pediatric dentists were less likely to use amalgam than general dentists. Girls and patients with higher socioeconomic status were less likely to have amalgam. PRACTICAL IMPLICATIONS: The findings of this study can inform and support clinical decisions and the formation of public policies.

Evaluation of the reasons for failure in teeth with vital amputation treatment.

AIM: This study aims to evaluate the primary teeth undergoing amputation due to dental caries or trauma clinically and radiologically. MATERIAL AND METHODS: The amputation treatment of 90 primary teeth of 58 patients (Female: 20, Male: 38) aged 4-11 years was evaluated clinically and radiologically. Calcium Hydroxide was used for amputation in this study. Composite or amalgam was preferred as filling material in the same session of the patients. Clinical/radiological (Periapical/Panoramic X-ray) examination was performed on the teeth that were unsuccessful in treatment, on the day of the patient's complaint, and at the end of 1 year in the others. RESULTS: According to the clinical and radiological findings of the patients, 14.4% of the boys and 12.3% of the girls were unsuccessful. Amputation in male was a need in the 6-7 age group with a rate of 44.6% at most. Amputation in females was a need in the 8-9 age group with a rate of 52% at most. CONCLUSION: Success in amputation treatment depends on the tooth, the dentist, and the dental material applied.

The long-forgotten technique of pin retained restoration - A case report.

To restore severely damaged teeth to the greatest state for health, function, and aesthetics continues to be a challenge for all practising dental surgeons. A pin retained restoration is an intricate restoration involving the insertion of one or more pins into the dentin to provide sufficient resistance and retention. These pins help in anchoring dental amalgam or composite to the tooth structure. This auxiliary retentive means help in the restoration of mutilated teeth in young individuals whose pulp chambers are relatively large and the dentinal tubules are comparatively immature. This case study sheds insights on the successful rehabilitation of a severely damaged premolar tooth with pins and composite resin restoration.

A survey of amalgam use to guide dental education curriculums.

OBJECTIVES: To identify behavioral, preferential, and professional factors influencing the use of amalgam in private practices; and to compare the incidence of the placement of amalgam versus composite resin restorations in the province of Ontario and its pedagogical implications on dental curricula. METHODS: Participants responded anonymously to a 23-question online survey about their current use of dental amalgam and composite resins as well as their opinions regarding both dental materials. The explanatory variables were associated bivariately with the outcome variables, and the most significant predictors were identified using the multivariate analysis. RESULTS: Higher percentages of amalgam use were reported among clinicians who trained in Canada only (P = .009), who graduated before 1980 (p = <.001) and who work outside private practice (p = <.001). Familiarity with amalgam was higher among clinicians who are female (p = <.001), older (p = <.001), trained only in Canada (p = .017), who graduated prior to 2000 (p = <.001), and who work in locations with populations over 100,000 (p = .042). Familiarity with composite resin was higher among clinicians who graduated more recently (p = .002). A higher percentage of females (p = <.001), younger clinicians (p = <.001), recent graduates (p = <.001), and clinicians who work in private practice (p = .043) suggested that over 50% of dental student training time be allocated to amalgam. CONCLUSIONS: Decreased amalgam use was reported by later dental graduates and private practitioners; this may be impacted by familiarity with dental amalgam. As amalgam remains a safe and effective dental material, its removal may not be prudent. Dental educators play a crucial role in the future of amalgam opinion and use.

Teaching of posterior composites for the restoration of permanent teeth in undergraduate dental training programmes: Systematic review and meta-analysis.

OBJECTIVES: To systematically assess aspects of teaching of posterior composite restorations (PCRs) in permanent teeth in dental schools. STUDY SELECTION: Quantitative studies reporting on dental schools' teaching regarding the placement of PCRs in permanent teeth. Random-effects meta-analyses and meta-regressions were performed. Risk of bias was assessed based on the Medical Education Research Study Quality Instrument (MERSQI). SOURCES: Electronic databases (MEDLINE via PubMed, EMBASE via Ovid, Web of Science, and Scopus) were searched in January 2023. DATA: Forty sources reporting on 34 studies having surveyed 1,286 dental schools were included. Overall, 92.7% (95%-CI: 88.2-95.5) of dental schools reported to teach PCRs. PCRs in three-surface Class II cavities are taught by 82.0% (95%-CI: 70.4-89.7). The mandatory use of liners in deep cavities is taught by 78.3% (95%-CI: 68.9-85.5), and 44.0% (95%-CI: 34.3-54.2) reported to teach bulk-fill composites. While most posterior restorations placed by students were composites (56.1%; 95%-CI: 46.0-65.8), 94.7% (95%-CI: 86.6-98.0) of dental schools (still) teach posterior amalgam restorations. The proportion of dental schools teaching PCRs in three-surface Class II cavities increased and the mean proportion of PCRs among all posterior restorations increased over time (padj.≤0.003). CONCLUSIONS: The teaching of PCRs in dental schools around the world reflects the increased use of resin composite in clinical practice, with students in countries where dental amalgam continues to be used, placing more posterior composites than restorations of dental amalgam. The teaching of PCRs, which is anticipated to increase, will continue to be refined with further developments in adhesive materials, devices, instrumentation, and techniques. CLINICAL SIGNIFICANCE: Graduating dentists can be expected to be familiar with the use of resin composites for the restoration of posterior teeth.

Evaluation of diagnostic accuracy of CBCT and intraoral radiography for proximal caries detection in the presence of different dental restoration materials.

PURPOSE: This study aimed to assess the diagnostic accuracy of cone-beam computed tomography (CBCT) and digital intraoral radiography for the detection of proximal caries adjacent to amalgam, e.max porcelain, and metal-ceramic restorations (MCRs). MATERIALS AND METHODS: Parallel intraoral radiographs were obtained from 40 posterior teeth using PSP sensors. To obtain CBCT scans, the teeth were first radiographed alone, and were then positioned next to a tooth with an amalgam restoration, MCR, and e.max porcelain crown, and radiographed again. Two blinded observers scored radiographs using a four-point scale (0: absence of proximal caries, 1: enamel caries, 2: carious lesion extending to the outer half of dentin, 3: carious lesion extending to the inner half of dentin). Tooth sections were made, and the grade of caries was determined under a light microscope at x12 magnification. The sensitivity, specificity, and accuracy of CBCT and intraoral radiographs were then calculated. RESULTS: Artifact-free CBCT scans and intraoral radiographs had the highest diagnostic accuracy (0.826 and 0.657, respectively) while CBCT images of the teeth next to the amalgam restorations (0.526) had the lowest accuracy. The diagnostic accuracy of CBCT images of the teeth next to the porcelain crowns and MCRs was 0.613 and 0.601, respectively. CONCLUSION: Artifact-free CBCT images had higher diagnostic accuracy than intraoral radiography for the detection of all grades of proximal caries. The diagnostic accuracy of CBCT images of teeth adjacent to amalgam, porcelain, and MCRs was lower compared to intraoral radiographs and artifact-free CBCT images.

Mercurial risk from dental amalgam use in a population of Moroccan dentists: A latent class regression approach.

BACKGROUND: Dentists using dental amalgam are chronically exposed to low doses of elemental mercury. The complex toxico-kinetics of this systemic toxicant results in polymorphic and variable clinical phenotypes. In this context, adapted statistical methods are required to highlight potential adverse effects of occupational mercury exposure on dentists' health. OBJECTIVE: The present study aims to analyze the distribution of self-reported subjective symptoms, commonly associated with chronic mercury poisoning, according to occupational mercury exposure in a population of Moroccan liberal dentists. METHODS: In order to achieve the defined objectives, a three-step latent class regression was fitted. First a latent class analysis was performed to cluster the studied population according to their declared symptoms. Dentists were then classified in the defined latent classes based on their posterior probabilities. Finally, a logistic regression is fitted to identify predictors associated with the latent classes' membership. RESULTS: The final obtained model showed acceptable calibration and discrimination. Its interpretation revealed that the increase of the frequency of amalgam use was associated with significant higher odds of belonging to the high risk latent class. CONCLUSIONS: The present study represents an initial step towards the development of diagnosis model that predict clinical profiles according to occupational mercury exposure.

Prevalence and mean number of teeth with amalgam and nonamalgam restorations, United States, 2015 through 2018.

BACKGROUND: Amalgam has been used for more than 150 years as a safe and reliable restorative material. The authors described the occurrence of amalgam and nonamalgam restorations in the United States in primary and permanent teeth across age groups and according to sociodemographic characteristics. METHODS: The authors used clinical examination data from the National Health and Nutrition Examination Survey 2015-2018 for participants 2 years and older (n = 17,040). The authors estimated the prevalence and mean number of amalgam and nonamalgam restorations in primary and permanent teeth according to age groups (2-5 years, 6-11 years, 12-15 years, 16-19 years, 20-39 years, 40-59 years, 60-79 years, and ≥ 80 years), race and ethnicity, federal poverty guideline, education, and pregnancy status. RESULTS: The prevalence of amalgam restorations ranged from 4% through 69%. Overall, amalgam restorations were more prevalent in children and adolescents from racial and ethnic minority groups and families at lower poverty levels and with lower education. The mean number of teeth with nonamalgam restorations was higher than those with amalgam restorations in primary teeth of children aged 6 through 11 years, permanent teeth of those 12 through 15 years and 20 through 39 years, and women aged 20 through 49 years, regardless of pregnancy status. The mean number of amalgam restorations was higher than that for nonamalgam restorations in older age groups. CONCLUSIONS: Nonamalgam restorations were the most common in the primary teeth of children older than 5 years and in the permanent teeth of adults younger than 40 years. Amalgam restorations were more common in older adults. Amalgam and nonamalgam restorations were equally common in children younger than 5 years. PRACTICAL IMPLICATIONS: The study findings suggest a shift from amalgam to alternative restorative materials in the United States.

Posterior dental restoration material choices in privately insured people in the United States, 2017 through 2019.

BACKGROUND: In the context of evolving dental materials and techniques and a national agenda to phasedown use of dental amalgam, estimates of dental amalgam placement are necessary for monitoring purposes. METHODS: Numbers of amalgam and composite posterior restorations from 2017 through 2019 were calculated using retrospective dental claims analysis of privately insured patients. Kruskal-Wallis and multilevel, multivariable negative binomial regression models were used to test for differences in rates of amalgam and composite restoration placement by age group, sex, urban or rural area, and percentage race and ethnicity area distribution. Statistical significance was set at 0.05, with Benjamini-Hochberg correction for false discovery rate. RESULTS: The rate of amalgam restorations declined over time from a mean of 6.29 per 100 patients in 2017 to 4.78 per 100 patients in 2019, whereas the composite restoration rate increased from 27.6 per 100 patients in 2017 to 28.8 per 100 in 2019. The mean number of amalgam restorations placed per person were lowest in females compared with males, in urban areas compared with rural areas, and in areas with more than 75% non-Hispanic White residents. CONCLUSIONS: Amalgam restoration placements in privately insured people in the United States declined from 2017 through 2019. Amalgam restoration placements may be unevenly distributed by location. PRACTICAL IMPLICATIONS: Achieving further declines of dental amalgam use may require changes to insurance coverage, incentives, and provider training as well as augmented disease prevention and health promotion efforts. These efforts should focus particularly on groups with high caries risk or higher rates of amalgam placement.