Do endodontic compounds induce genetic damage? A comprehensive review

Effects of natural antimicrobial compounds propolis and copaiba on periodontal ligament fibroblasts, molecular docking, and in vivo study in Galleria mellonella

Root canal treatment addresses infectious processes that require control. Occasionally, the radicular pulp is vital and inflamed, presenting a superficial infection. To preserve pulpal remnants, conservative procedures have gained favor, employing anti-inflammatory medications. This study investigated the effects of propolis (PRO), and copaiba oil-resin (COR) associated with hydrocortisone (H) and compared their impact to that of Otosporin® concerning cytotoxic and genotoxic activity, cytokine detection, and toxicity in the Galleria mellonella model. Human periodontal ligament fibroblasts (PDLFs) were exposed to drug concentrations and evaluated by the MTT assay. Associations were tested from concentrations that did not compromise cell density. Genotoxicity was evaluated through micronucleus counting, while cytokines IL-6 and TGF-β1 were detected in the cell supernatant using ELISA. Molecular docking simulations were conducted, considering the major compounds identified in PRO, COR, and H. Increasing concentrations of PRO and COR were assessed for acute toxicity in Galleria mellonella model. Cellular assays were analyzed using one-way ANOVA followed by Tukey tests, while larval survivals were evaluated using the Log-rank (Mantel-Cox) test (α = 0.05). PRO and COR promoted PDLFs proliferation, even in conjunction with H. No changes in cell metabolism were observed concerning cytokine levels. The tested materials induce the release of AT1R, proliferating the PDFLs through interactions. PRO and COR had low toxicity in larvae, suggesting safety at tested levels. These findings endorse the potential of PRO and COR in endodontics and present promising applications across medical domains, such as preventive strategies in inflammation, shedding light on their potential development into commercially available drugs.

Effect of blood contamination on marginal adaptation of cold ceramic and MTA angelus: a scanning electron microscopic study

BACKGROUND

This study aimed to assess the effect of blood contamination on marginal adaptation of cold ceramic (CC) and mineral trioxide aggregate (MTA) Angelus using scanning electron microscopy (SEM).

METHODS

This in vitro experimental study was conducted on 24 extracted single-rooted human teeth. After cleaning and shaping, the root canals were filled with lateral compaction technique. The apical 3 mm of the roots was cut, and cavities with 3 mm depth were created at the apex. The teeth were randomly assigned to two group (n = 12) for the application of CC and MTA Angelus as retrograde filling materials. CC and MTA Angelus were prepared by mixing the powder with blood, and applied in the cavities. After 24 h, their marginal adaptation to the canal walls was assessed by SEM. Data were statistically analyzed by t-test (alpha = 0.05).

RESULTS

The mean marginal gap was 8.98 μm in the CC, and 16.26 μm in the MTA Angelus group; this difference was statistically significant (P < 0.001).

CONCLUSIONS

The present in vitro study revealed that following complete blood contamination of powder, CC showed significantly superior marginal adaptation than MTA Angelus as shown by SEM assessment.

Adhesive Ability of Different Oral Pathogens to Various Dental Materials: An In Vitro Study

Introduction

In dental treatments, the reason for secondary caries and the failure of root canal treatment is the microbial infection, which concerns most dentists. The challenge of how to reduce the number of bacteria at the filling materials and the number of residual bacteria in the root canal has become a research hotspot. In this study, the bacterial adhesion properties of several common dental materials were compared to provide a theoretical basis for the selection of antibacterial properties of dental materials. Methodology. Three commonly used dental restorative materials and five sealers in root canal treatment were selected. Each material block was immersed in the corresponding supragingival (Streptococcus mutans and Actinomyces viscosus) or subgingival (Porphyromonas gingivalis and Enterococcus faecalis) bacterial solution and cultured under anaerobic conditions at 37°C for 2, 4, 6, 8, 12, 16, 20, and 24 h. The adhesion of bacteria was observed, and the number of different bacteria adhering to various material model disks was calculated at different time intervals under a scanning electron microscope. The adherent CFU load of the materials was determined by colony counting.

Results

Streptococcus mutans and Actinomyces viscosus exhibited the strongest adhesion ability to the resin material blocks. Porphyromonas gingivalis and Enterococcus faecalis exhibited the highest adhesion ability to the AH-Plus sealer block.

Conclusions

In dental treatments, dental materials should be selected based on the chemical, physical, and biological properties of materials. In addition, it is necessary to develop new antibacterial dental materials.

Assessment of toxicity and oxidative DNA damage of sodium hypochlorite, chitosan and propolis on fibroblast cells

The objective of this study was to evaluate and compare the cytotoxicity and genotoxicity on human fibroblast cell lines of sodium hypochlorite (NaOCl), chitosan and propolis as root canal irrigating solutions. Human fibroblast cells were exposed to chitosan, propolis and NaOCl for 4 and 24 h. Cell viability was assessed by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide, and oxidative DNA damage was assessed by determination of 8-hydroxydeoxyguanosine (8-OHdG) level with an ELISA kit. The data of cell cytotoxicity were analysed statistically using a test of one-way analysis of variance at a significance level of p < 0.05. In the NaOCI group, the 8-OHdG level was higher than in the chitosan group, but there was no statistical difference when compared with the other groups (p < 0.05). It was determined that the irrigation solutions were cytotoxic, depending on the dose and time. NaOCl was the most toxic solution after both 4 and 24 h of exposure (p < 0.05). Chitosan and propolis may be alternatives to NaOCl for irrigation solutions, because they are both less toxic and produce less oxidative DNA damage.

Synthesis of a Ca3 SiO5 -Ca2 SiO4 -Ca3 Al2 O6 cement system with rapid setting capacity by spray-pyrolysis coupled with sol-gel method

A modified mineral-trioxide-aggregate (mMTA) with rapid setting capacity was newly synthesized by spray-pyrolysis following a sol-gel reaction. Its faster setting capacity and initially higher compressive strength compared with Portland cement (PC) were evaluated. The precursor solution of the mMTA was prepared through condensation following hydrolysis among Ca(NO₃ )₂ ·4H₂ O, Si(OC₂ H₅ )₄ , and Al(NO₃ )₃ ·9H₂ O under nitric acid. The mMTA powder was then synthesized by spray-pyrolysis at 1500°C. The particle shape was spherical with an average particle size of 0.8 ± 0.3 μm, while PC particles were irregular and 3.9 ± 3.0 μm in size. The mMTA consisted of mostly Ca₃ SiO₅ , Ca₃ Al₂ O₆ , and partial Ca₂ SiO₄ phases, while the PC comprised mainly Ca₃ SiO₅ , Ca₂ SiO₄ , and partial Ca₃ Al₂ O₆ phases. The final setting times of mMTA and PC measured under 95% relative humidity were about 11 min and 3 h, respectively. The early stage of setting in mMTA was dominated by the rapid formation of hexagonal-plate-like Ca₃ Al₂ O₆ ·6H₂ O crystals, while that in PC was dominated by needle-like calcium-silicate-hydrate gels and columnar-shaped Ca(OH)₂ crystals. The late stage of setting in mMTA was dominated by calcium-silicate-hydrate gels and Ca(OH)₂ crystals, while that in PC was dominated by Ca₃ Al₂ O₆ ·6H₂ O crystals. The compressive strengths of mMTA and PC after 30 min of setting were 4.5 and 0.2 MPa, respectively. The results suggest that mMTA has potential to be used as a filling material for accidental pulp-exposure or pulpal floor perforation cases that require rapid setting capacity and initial good strength. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1440-1451, 2019.

Dissecting the Subcellular Localization, Intracellular Trafficking, Interactions, Membrane Association, and Topology of Citrus Leprosis Virus C Proteins

Citrus leprosis (CL) is a re-emergent viral disease affecting citrus crops in the Americas, and citrus leprosis virus C (CiLV-C), belonging to the genus Cilevirus, is the main pathogen responsible for the disease. Despite the economic importance of CL to the citrus industry, very little is known about the performance of viral proteins. Here, we present a robust in vivo study around functionality of p29, p15, p61, MP, and p24 CiLV-C proteins in the host cells. The intracellular sub-localization of all those viral proteins in plant cells are shown, and their co-localization with the endoplasmic reticulum (ER), Golgi complex (GC) (p15, MP, p61 and p24), actin filaments (p29, p15 and p24), nucleus (p15), and plasmodesmata (MP) are described. Several features are disclosed, including i) ER remodeling and redistribution of GC apparatus, ii) trafficking of the p29 and MP along the ER network system, iii) self-interaction of the p29, p15, and p24 and hetero-association between p29-p15, p29-MP, p29-p24, and p15-MP proteins in vivo. We also showed that all proteins are associated with biological membranes; whilst p15 is peripherally associated, p29, p24, and MP are integrally bound to cell membranes. Furthermore, while p24 exposes an N-cytoplasm-C-lumen topology, p29, and p15 are oriented toward the cytoplasmic face of the biological membrane. Based on our findings, we discuss the possible performance of each protein in the context of infection and a hypothetical model encompassing the virus spread and sites for replication and particle assembly is suggested.

Antimicrobial effect of calcium hydroxide as an intracanal medicament in root canal treatment: a literature review - Part I. In vitro studies

The goal of endodontic treatment is the prevention and control of pulpal and periradicular infections. Calcium hydroxide (Ca(OH)2) has been widely used in endodontics as an intracanal medicament to eliminate the remaining microorganisms after chemomechanical preparation. The purpose of this article is to review the antimicrobial properties of Ca(OH)2 as an intracanal medicament in root canal treatment. The first part of this review details the characteristics of Ca(OH)2 and summarizes the results of in vitro studies related to its antimicrobial effect. The antimicrobial effect of Ca(OH)2 results from the release of hydroxyl ions when it comes into contact with aqueous fluids. Ca(OH)2 has a wide range of antimicrobial effects against common endodontic pathogens, but is less effective against Enterococcus faecalis and Candida albicans. The addition of vehicles or other agents might contribute to the antimicrobial effect of Ca(OH)2.

Genotoxicity of Endosseous Implants Using Two Cellular Lineages In Vitro

The genotoxic potential of corrosion eluates obtained from a single dental implant using murine fibroblasts or osteoblasts cells in vitro by the single-cell gel (comet) assay was examined. A single commercially available dental implant (Biotechnology) was eluted in a solution consisting of equal amounts of acetic acid and sodium chloride (0.1 M) for 1, 3, 7, 14, and 21 days. Murine fibroblast or osteoblast cultures were then exposed to all corrosion eluates obtained from endosseous dental implants for 30 minutes at 37°C. The results suggest that none of the eluates produced genotoxic changes in murine fibroblasts regardless of the length of exposure to the eluate. Similarly, no genotoxicity was found in osteoblasts. The results suggest that the dental implant eluates tested in this study did not induce genetic damage as depicted by the single-cell gel (comet) assay. Because DNA damage is an important event during oncogenesis, this study represents a relevant contribution to estimate the real risks to the cellular system induced by the corrosion products of a dental implant.

Retrieval of extensive gutta-percha extruded into the maxillary sinus: use of 3-dimensional cone-beam computed tomography

INTRODUCTION

Close proximity of the maxillary sinus to the roots of maxillary teeth can predispose to the inadvertent deposition of endodontic products into the maxillary sinus. One such material is thermoplasticized injectable gutta-percha, which has gained popularity of late. As a consequence of overfilling, some patients warrant surgical retrieval.

METHODS

A case report of extreme overextension of gutta-percha within the maxillary sinus after endodontic retreatment on tooth #14 was provided. The distobuccal and palatal canals had been obturated with gutta-percha master cones and backfilled with thermoplasticized injectable warm gutta-percha. The mesiobuccal canal had only been filled with thermoplasticized injectable warm gutta-percha, the origin of the extrusion. Imagery with 3-dimensional cone-beam computed tomography was performed for localization of the gutta-percha.

RESULTS

The patient underwent a Caldwell-Luc approach for removal of the extruded material. The gutta-percha was successfully removed intact, and the patient had an unremarkable postoperative course. However, the patient continues to have mild tenderness in the sinus region.

CONCLUSIONS

The featured case exemplified the consequence of overinstrumentation and ensuing inadequate apical stop. In these situations, the obturation of a maxillary tooth with thermoplasticized injectable gutta-percha, without master cones, can potentially result in overfilling and deposition into the antrum. Use of 3-dimensional cone-beam computed tomography could enhance endodontic diagnosis, serve as an aid for visualization of foreign materials within the sinus and contiguous soft tissue structures, and improve clinical outcome.

Dental methacrylates may exert genotoxic effects via the oxidative induction of DNA double strand breaks and the inhibition of their repair

Methacrylate monomers used in dentistry have been shown to induce DNA double strand breaks (DSBs), one of the most serious DNA damage. In the present work we show that a model dental adhesive consisting of 45% 2-hydroxyethyl methacrylate (HEMA) and 55% bisphenol A-diglycidyl dimethacrylate (Bis-GMA) at concentrations up to 0.25 mM Bis-GMA induced oxidative DNA in cultured primary human gingival fibroblasts (HGFs) as evaluated by the comet assay and probed with human 8-hydroxyguanine DNA-glycosylase 1. HEMA/Bis-GMA induced DSBs in HGFs as assessed by the neutral comet assay and phosphorylation of the H2AX histone and sodium ascorbate or melatonin (5-methoxy-N-acetyltryptamine) both at 50 μM reduced the DSBs, they also inhibited apoptosis induced by HEMA/Bis-GMA. The adhesive slowed the kinetics of the repair of DNA damage induced by hydrogen peroxide in HGFs, while sodium ascorbate or melatonin improved the efficacy of H₂O₂-induced damage in the presence of the methacrylates. The adhesive induced a rise in the G2/M cell population, accompanied by a reduction in the S cell population and an increase in G0/G1 cell population. Sodium ascorbate or melatonin elevated the S population and reduced the G2/M population. In conclusion, HEMA/Bis-GMA induce DSBs through, at least in part, oxidative mechanisms, and these compounds may interfere with DSBs repair. Vitamin C or melatonin may reduce the detrimental effects induced by methacrylates applied in dentistry.

"MTA"-an Hydraulic Silicate Cement: review update and setting reaction

OBJECTIVES

To review the current status and understanding of Portland cement-like endodontic materials commonly referred to by the trade designation "MTA" (alias "Mineral Trioxide Aggregate"), and to present an outline setting reaction scheme, hitherto unattempted.

METHOD

The literature was searched using on-line tools, overlapping an earlier substantial review to pick up any omissions, including that in respect of ordinary Portland cement (OPC), with which MTA shares much. The search was conducted for the period January 2005 to December 2009 using 'MTA', 'GMTA', 'WMTA', and 'mineral AND trioxide AND aggregate' as keywords, with various on-line search engines including ScienceDirect (http://www.sciencedirect.com), SAGE Journals Online (http://online.sagepub.com), Wiley Online Library (http://onlinelibrary.wiley.com), SciELO Scientific electronic library online (http://www.scielo.br/scielo.php), JSTOR (http://www.jstor.org), and Scopus (http://www.scopus.com). References of articles found were cross-checked where appropriate for missed publications. Manufacturers' and related websites were searched with Google Search (http://www.google.com.hk).

RESULTS

A generic name for this class of materials, Hydraulic Silicate Cement (HSC), is proposed, and an outline reaction scheme has been deduced. HSC has distinct advantages apparent, including sealing, sterilizing, mineralizing, dentinogenic and osteogenic capacities, which research continues to demonstrate. However, ad hoc modifications have little supporting justification.

SIGNIFICANCE

While HSC has a definite place in dentistry, with few of the drawbacks associated with other materials, some improvements in handling and other properties are highly desirable, as are studies of the mechanisms of the several beneficial physiological effects. Reference to the extensive, but complex, literature on OPC may provide the necessary insight.

The obsolescence of formocresol

Concern has existed for almost ten years regarding the safety and efficacy of formaldehyde-based medicaments like formocresol in dentistry. Formocresol has been shown to be therapeutically outdated for decades. While the use of formocresol around the world continues to drop, it is still utilised in alarmingly high rates, an age-old bias that is unsubstantiated by overall academic research. Formaldehyde remains a genotoxic and carcinogenic problem worldwide. The most recent articles are discussed in the light of the need to abandon formocresol.

Biomonitoring of oral epithelial cells in petrol station attendants: comparison between buccal mucosa and lateral border of the tongue

Owing to the influence of geno- and cytotoxicity on chemical carcinogenesis, studies have demonstrated that petroleum derivatives are able to induce genetic damage and cellular death with conflicting results so far. The aim of the present study was to comparatively evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated oral mucosa cells from gas petrol attendants using two different anatomic buccal sites: cheek mucosa and lateral border of the tongue. A total of 23 gas petrol attendants and 23 health controls (non-exposed individuals) were included in this setting. Individuals had epithelial cells from cheek and lateral border of the tongue mechanically exfoliated, placed in fixative and dropped in clean slides which were checked for the above nuclear phenotypes. The results pointed out significant statistical differences (p<0.05) of micronucleated oral mucosa cells from gas petrol attendants for both oral sites evaluated. In the same way, petroleum derivate exposure was able to increase other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis, being the most pronunciated effects as those found in the lateral border of the tongue. No interaction was observed between smoking and petroleum exposure. In summary, these data indicate that gas petrol attendants comprise a high risk group for DNA damage and cellular death. It seems that the lateral border of the tongue is a more sensitive site to geno- and cytotoxic insult induced by petroleum derivates.

In vitro genotoxicity of root canal sealers

AIM

To evaluate the effect of leakage on differences in genotoxicity of root canal sealers ex vivo according to their main components using two different cytogenetic assays.

METHODOLOGY

Six materials of different composition (GuttaFlow, Epiphany, Diaket, IRM, SuperEBA and Hermetic) were tested on human peripheral blood lymphocytes using the comet assay and chromosomal aberration analysis. Prepared materials were eluted in physiological solution for 1 h, 1 day, 5 and 30 days. Thereafter cultures were treated with 8 microg, 4 microg and 2 microg of each sealer. Frequencies of chromatide and chromosome breaks and accentric fragments were determined. Comet assay was used to evaluate primary DNA damage by measuring tail length and tail intensity. Chi-square, Fisher's PLSD (Protected Least Significant Difference) and Kruskall-Wallis non parametric tests were used for statistical analysis.

RESULTS

After 1-h elution only the highest dose of Diaket, Hermetic and SuperEBA significantly (P = 0.035, P = 0.048, P = 0.037 respectively) affected the measured cytogenetic parameters. The migration ability of DNA was more strongly affected than induction of chromosomal aberrations. After elutions longer than 24 h none of the tested sealers exhibited a genotoxic effect.

CONCLUSION

Under the conditions used in the study all sealers had acceptable biocompatibility in terms of genotoxicity.