Genotoxic effects of silver amalgam and composite restorations: Micronuclei-Based cohort and case–control study in oral exfoliated cells

Abstract

Context:A huge number of people carry dental fillings which contain either mercury-based amalgam and/or the recently introduced methacrylate-based resins. It has been shown that both these materials are known to be leached into the oral cavity and induce genotoxic alterations in the buccal mucosal cells. Because of its low cost and ease of manipulation, dental amalgam is still widely used as a restorative material in developing countries. The health risks associated with the components of this restorative material has always been a matter of concern. The present study was designed to assess the frequency of micronuclei (MN) in oral mucosal cells as it is a promising tool for studying the genotoxic effect of clastogenic agents on them.Aims:The aim of this study is to evaluate the genotoxic effects of silver amalgam and composite restorations by measuring the mean number of MN in oral exfoliated cells.Materials and Methods:The present study was a prospective cohort study which includes a study group consisting of 110 participants. The study sample was equally divided into 55 participants requiring only amalgam restoration and 55 participants requiring only composite restoration in any permanent molar teeth. The same participants before the restoration formed the control group. Smears were obtained from each patient before and 10 days after restoration and were stained with DNA-specific Feulgen stain. The number of cells containing MN out of 500 cells were counted and recorded. After the evaluation of the slides, the results were compiled and subjected to statistical analysis.Results:There was a statistically significant (P < 0.01) variation in the mean number of MN after the restoration in both amalgam (5.41 ± 1.25) and composite (2.83 ± 0.85) restorations when compared to before the restoration. However, the mean number of MN in composite restoration was significantly less when compared to amalgam restoration. There was also a statistically significant difference in the mean number of MN in subjects with single restoration when compared with multiple restorations in both amalgam and composite restorations.Conclusions:The observations from the present study showed the genotoxic effect of amalgam and composite restorations on the oral cavity. However, composite restorations were least cytotoxic when compared to amalgam restoration. Future research and technical advancements are needed for developing safer materials for use in humans.

Assessment of Cytotoxic and Genotoxic Effect of Modern Dental Materials in vivo

“…amalgam (p=0.003) and composite (p=0.006) with beta-coefficients of 0.237 and 0.221. The above mentioned results are consistent with the findings of previous research ( 13 , 33 , 34 ), which stated that a higher level of DNA damage in the cells was correlated with a higher number of fillings. A multivariate regression analysis was performed to determine the associations between potential genotoxic factors related to patients' lifestyle and micronucleus test parameters.…”

“…Ahmed et al ( 33 ) stated that in subjects with composite fillings, cytotoxic changes on human buccal and labial cells become more pronounced the longer the filling is in the oral cavity, while in amalgam fillings the greatest toxic damage was observed in the first few hours after the filling was placed. Mary et al ( 34 ) reported that in their study that the average number of MNs in the cells of amalgam filling carriers was statistically significantly higher than that of composite fillings. Likewise, the average number of MNs in the cells of subjects with amalgam and composite fillings was statistically significantly higher compared to the cells of participants without fillings.…”

“…Numerous papers ( 13 , 31 - 34 ) stated the influence of time on the cytotoxicity and genotoxicity of dental materials. The purpose of the current in vivo study was to use the MN test to analyze buccal epithelial cells from the vicinity of amalgam and composite fillings that were exposed to the conditions of the oral cavity for longer than 6 months but not longer than 12 months.…”

“…For this reason, constant monitoring and ex vivo and in vivo research of all dental materials is needed, even though they have passed all tests and received permission for official use ( 29 - 32 ). Since numerous studies have reported a correlation between the age of fillings and the degree of cell damage ( 13 , 33 , 34 ), in this study a swab of buccal cells was taken near composite and amalgam fillings aged six to twelve months. The goal was to evaluate the potential cytotoxic and genotoxic effects of fillings on the cells of the oral mucosa using the extended micronucleus (MN) test (cytomeassay).…”

Genotoxicity of Mercury and Its Derivatives Demonstrated In Vitro and In Vivo in Human Populations Studies. Systematic Review

“…Similar results were obtained by Mary et al (2018) using MN test in the oral mucosa cells [83]. The analysis of the alterations was carried out in the same subject before and after dental restoration with amalgams, serving as their own controls.…”