In vitro and in vivo evaluations of glass-ionomer cement containing chlorhexidine for Atraumatic Restorative Treatment

Organic antibacterial modifications of high-viscosity glass ionomer cement for atraumatic restorative treatment: A review

High viscosity glass ionomer cement (HVGIC) has been employed as a restorative material for Atraumatic Restorative Treatment (ART). As residual caries persist after caries removal in ART, the antibacterial activity of HVGIC gains importance. Organic and inorganic substances with antibacterial properties have been incorporated into HVGIC over the years, and their effects on the antibacterial and physical properties have been studied. The objective of this paper is to review the various alterations made to HVGIC using organic compounds, their effect on the antibacterial activity, and the physical properties of the cement. Various in vitro investigations have been conducted by adding antiseptics, antibiotics, and naturally occurring antibacterial substances. Most of these compounds render superior antibacterial properties to HVGIC, but higher concentrations affect physical properties in a dose-dependent manner. However, some naturally occurring antibacterial substances, such as chitosan, improve the physical properties of HVGIC, as they enhance cross-linking and polysalt bridging. There is potential for clinical benefits to be gained from the addition of organic antibacterial compounds to HVGIC. In-depth research is required to determine the optimum concentration at which the antibacterial effect is maximum without affecting the physical properties of the cement.

Glass ionomer cement particles pre-reacted with chlorhexidine: Physical/chemical properties and antimicrobial activity

OBJECTIVE

Analyze the effects of the functionalization of pre-functionalized GIC particles with chlorhexidine on the physicochemical properties and antimicrobial activity.

MATERIALS AND METHODS

Four groups were prepared: (1) GIC (Bioglass R - Biodinamica) - control group; (2) GIC-CHX 1%: Group containing 1% pre-reacted CHX particles; (3) GIC-CHX 2.5%: Group containing 2.5% pre-reacted CHX particles; (4) GIC-CHX 5%: Group containing 5% pre-reacted CHX particles. Hourglass-shaped specimens (10 mm × 2 mm x 1 mm) were fabricated for mechanical tests including cohesive strength (n = 12), modulus of elasticity (n = 12) and microhardness (n = 10). Discs (10 mm × 2 mm) were prepared for the analysis of Ca+2, PO4- and F- ions release (n = 3), and roughness (n = 12). To evaluate the setting time, a Gilmore needle was used according to ISO 9917-1:2016. Disk-shaped specimens (5 × 1mm) were manufactured and subjected to bacterial activity (n = 9) (Streptococcus mutans ATCC 159).

RESULTS

Modulus, roughness, setting time and ions release (Ca+2, PO4-, and F-) there were no statistically significant differences among the groups (p > 0.05). The setting time did not change with the incorporation of CHX. The GIC-CHX 2.5% and GIC-CHX 5% groups exhibited superior antibacterial activity compared to the control group and GIC-CHX 1% (p < 0.001). The GIC-CHX 5% group showed the highest microhardness values (p < 0.041), cohesive strength (p < 0.009) when compared to the control group.

CONCLUSION

The pre-reacted CHX in GICs was able to confer antimicrobial activity, improve cohesive strength, microhardness, and did not impair ion release, setting time, and roughness.

Miswak-Infused Glass Ionomer Cement: A Comparative In Vitro Analysis of Antibacterial Efficacy and Compressive Strength

BACKGROUND

Glass ionomer cement (GIC) restorations are commonly used in primary dentition, due to their aesthetic appeal, self-adhesive nature, and biocompatibility. However, the material's limited antibacterial activity and inadequate mechanical strength highlight the necessity for modifying the material.

AIM

The study aims to evaluate and compare the antimicrobial potency and compressive strength of GIC-incorporated Miswak extract with that of conventional GIC.

MATERIALS AND METHODS

After obtaining the Miswak extract, a modified GIC was formulated by combining the extract with the conventional GIC powder and liquid components, in three different ratios (Powder: Extract and Liquid), Group I (2:1:1), Group II (3:1:2), Group III (3:2:1), and the Group IV as control, which consist of unmodified/conventional GIC. To evaluate and compare the antibacterial efficacy of the modified and unmodified GIC, standard strains of Streptococcus mutans and Lactobacillus were utilized. For each group, the minimal inhibitory concentration (MIC) assay was tested. For the evaluation of compressive strength, cylindrical moulds were utilized in compliance with ISO 9917-1:2007 standards and tested using the universal testing machine (Instron, ElectroPuls®, Bangalore, IND). The highest force exerted at the point of specimen fracture was recorded to calculate the compressive strength values in MPa. The data obtained were analyzed using the Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 24.0, Armonk, NY) software. The statistical analysis was conducted utilizing repeated measures of analysis of variance (ANOVA) to calculate the mean MIC values and compressive strength, with pairwise comparisons assessed using Tukey's post hoc test.

RESULTS

The results proved that the antimicrobial properties of Miswak containing GIC performed better against S. mutans and Lactobacillus with a statistically significant difference when compared with group IV (p<0.05), it has been found that an increase in the concentration of extract increased the antimicrobial potency. Significant results were obtained in compressive strength where Group II (41.49±3.6) and Group III (15.23±4.96) proved to be weaker than the control (62.69±2.58), while Group I showed no differences from the control group (p>0.05).

CONCLUSION

It can be concluded that Group I was found to be better in terms of both antimicrobial properties and compressive strength, where no significant difference in compressive strength was identified when comparing Group I with Group IV. Thus, the overall study depicts that a lesser concentration of extract can be the best option in terms of good antimicrobial properties without altering its strength. Hence, the Miswak containing GIC could be a promising restorative material; further studies should include considering intraoral variables such as masticatory stress, moisture levels and in-vivo tests of this combination.

Short-term Clinical and Microbiological Performance of Resin-modified Glass Ionomer Cement Containing Chlorhexidine for Atraumatic Restorative Treatment

Aim

This study evaluated the short-term clinical and microbiological performance of resin-modified glass ionomer cement (RM-GIC) cement containing chlorhexidine (CHX) for atraumatic restorative treatment (ART) in primary teeth.

Materials and methods

The clinical trial was conducted in 36 children that received ART in primary molars either with GIC (group I, n = 18) or GIC containing 1.25% CHX (group II, n = 18). The survival rate of restorations was checked 7 days, 3, and 6 months after their application when saliva and biofilm were collected for microbiological assessment of mutans streptococci (MS) counts. Data were analyzed using the Kruskal-Wallis/Mann-Whitney U tests for clinical analysis and microbiological evaluations (p < 0.05).

Results

The survival rate of restorations was similar comparing groups I with II. Microbiological analysis showed a significant reduction in MS levels 7 days after the treatment in both saliva and biofilm of children treated with RM-GIC containing CHX (group II); however, MS counts at 3 and 6 months did not differ from the initial counts.

Conclusion

A total of 1.25% CHX improved the microbiological properties of GIC in the short term without impairing the clinical performance of ART restorations.

Clinical significance

Glass ionomer cement (GIC) containing CHX could be an alternative in ART procedures with the objective of promoting an additional antimicrobial effect, which is interesting for children with high counts of MS during the initial phase of adaptation to dental treatment.

How to cite this article

da Silva ME, de Sena MD, Colombo NH, et al. Short-term Clinical and Microbiological Performance of Resin-modified Glass Ionomer Cement Containing Chlorhexidine for Atraumatic Restorative Treatment. Int J Clin Pediatr Dent 2023;16(S-1):S27-S32.

Biocompatible carboxymethyl chitosan-modified glass ionomer cement with enhanced mechanical and anti-bacterial properties

Due to the potential adverse effects of conventional dental cements, the demand for biocompatible cements have grown tremendously in the field of dentistry. In this respect, Glass ionomer cements (GICs) are being developed by different researchers. However, low mechanical strength of GIC make them unsuitable for application in high-stress areas. Thus, numerous initiatives to improve mechanical performance have been attempted till date including incorporation of reinforcing fillers. Novelty of the study lies in using carboxymethyl chitosan (CMC) to develop a biocompatible dental cement (DC/CMC-m-GP), which would have enhanced mechanical strength due to greater interaction of CMC with the particles of GIC and better cyto-compatibility due to its cell-proliferation activity. The mechanical strength, acid erosion and fluoride release of DC/CMC-m-GP were studied and compared with control dental cement (DC/Control). DC/CMC-m-GP shows compressive strength of 157.45 M Pa and flexural strength of 18.76 M Pa which was higher as compared to DC/Control. The morphology of the GICs were studied through FESEM. Anti-microbial activity of DC/CMC-m-GP was studied by Agar disc-diffusion method and biofilm assay against S. mutans, which shows that DC/CMC-m-GP inhibits bacterial adhesion on its surface. MTT assay infers that DC/CMC-m-GP was non-cytotoxic and did not affect the cell viability significantly.

Does the addition of chlorhexidine to glass ionomer cements influence its antimicrobial effect and survival rate? A systematic review

PURPOSE

To evaluate the influence of the addition of chlorhexidine on the antimicrobial effect and on the survival of restorations performed with glass ionomer cement.

METHODS

Nine databases were used to search for randomized clinical trials that compared the survival rate and the antimicrobial effect of glass ionomer cement (GIC) restorations with and without the incorporation of chlorhexidine (CHX), without restrictions on year or language. Cochrane Collaboration's Risk of Bias 2 was used to assess the risk of bias. The GRADE approach was used to assess the certainty of evidence.

RESULTS

From 593 studies found, seven met the inclusion criteria. The concentration of CHX varied between 0.5 and 2%. In general, the addition of CHX to GIC promoted reductions in Streptococcus mutans and Lactobacillus acidophilus burdens when compared to those without CHX. No study showed a difference in the survival of restorations between GIC with CHX and conventional GIC. Individual risk of bias varied from low to high and the certainty of evidence was classified as very low.

CONCLUSIONS

Based on a very low level of certainty, the evidence suggests that the incorporation of CHX in GIC might improve the antimicrobial effects for a short time, in addition to having little influence on the survival of the restoration.

Antimicrobial Efficacy of Glass Ionomer Cement in Incorporation with Biogenic Zingiber officinale Capped Silver-Nanobiotic, Chlorhexidine Diacetate and Lyophilized Miswak

In the present study, Zingiber officinale is used for the synthesis of Zingiber officinale capped silver nanoparticles (ZOE-AgNPs) and compares the antimicrobial efficacy and compressive strength of conventional glass ionomer cement (GIC) combined with ZOE-AgNPs, lyophilized miswak, and chlorhexidine diacetate (CHX) against oral microbes. Five groups of the disc-shaped GIC specimens were prepared. Group A: lyophilized miswak and GIC combination, Group B: ZOE-AgNPs and GIC combinations, Group C: CHX and GIC combination, Group D: ZOE-AgNPs + CHX + GIC; Group E: Conventional GIC. Results confirmed the successful formation of ZOE-AgNPs that was monitored by UV-Vis sharp absorption spectra at 415 nm. The X-ray diffractometer (XRD) and transmission electron microscope (TEM) results revealed the formation of ZOE-AgNPs with a mean size 10.5-14.12 nm. The peaks of the Fourier transform infrared spectroscopy (FTIR) were appearing the involvement of ZOE components onto the surface of ZOE-AgNPs which played as bioreducing, and stabilizing agents. At a 24-h, one-week and three-week intervals, Group D showed the significantly highest mean inhibitory zones compared to Group A, Group B, and Group C. At microbe-level comparison, Streptococcus mutans and Staphylococcus aureus were inhibited significantly by all the specimens tested except group E when compared to Candida albicans. Group D specimens showed slightly higher (45.8 ± 5.4) mean compressive strength in comparison with other groups. The combination of GIC with ZOE-AgNPs and chlorhexidine together enhanced its antimicrobial efficacy and compressive strength compared to GIC with ZOE-AgNPs or lyophilized miswak or chlorhexidine combination alone. The present study revealed that The combination of GIC with active components of ZOE-AgNPs and chlorhexidine paves the way to lead its effective nano-dental materials applications.

Ursolic Acid Targets Glucosyltransferase and Inhibits Its Activity to Prevent Streptococcus mutans Biofilm Formation

Streptococcus mutans (S. mutans), the prime pathogen of dental caries, can secrete glucosyltransferases (GTFs) to synthesize extracellular polysaccharides (EPSs), which are the virulence determinants of cariogenic biofilms. Ursolic acid, a type of pentacyclic triterpene natural compound, has shown potential antibiofilm effects on S. mutans. To investigate the mechanisms of ursolic acid-mediated inhibition of S. mutans biofilm formation, we first demonstrated that ursolic acid could decrease the viability and structural integrity of biofilms, as evidenced by XTT, crystal violet, and live/dead staining assays. Then, we further revealed that ursolic acid could compete with the inherent substrate to occupy the catalytic center of GTFs to inhibit EPS formation, and this was confirmed by GTF activity assays, computer simulations, site-directed mutagenesis, and capillary electrophoresis (CE). In conclusion, ursolic acid can decrease bacterial viability and prevent S. mutans biofilm formation by binding and inhibiting the activity of GTFs.

Comparative Evaluation of Antibacterial Effect of GIC Containing Chlorhexidine and Miswak on Streptococcus mutans and Streptococcus sobrinus in Early Childhood Caries Children: A PCR Study

Background and aim

The therapeutic procedures used in the treatment of caries do not always eliminate all the microorganisms. Persisting cariogenic bacteria can cause recurrent caries and failure of restoration. Incorporation of an antimicrobial agent in the restorative material may be of paramount significance. The purpose of this study was to evaluate and compare the antibacterial effect of glass ionomer cement (GIC) containing CHX and miswak extract on Streptococcus mutans and Streptococcus sobrinus in ECC children using polymerase chain reaction (PCR).

Materials and methods

Forty-five children with ECC in the age-group 3–6 years were selected. The children were randomly allocated into three groups. Supragingival plaque samples (S1) were collected from sound buccal or labial surfaces of primary teeth. Cavity preparation was done and the teeth were restored according to the group to which the child had been allotted. The second plaque sample (S2) was collected 1 month and the final sample after 3 months of restoring all the decayed teeth. All the samples were sent for PCR analysis.

Results

Intergroup analysis was done using Kruskal–Wallis test followed by Mann–Whitney post hoc test showed statistically significant difference in S. mutans and S. sobrinus count between group I (CHX) and group III (control) and group II (miswak) and group III (control) but no statistically significant difference between group I (CHX) and group II (miswak) in S. mutans and S. sobrinus count.

Conclusion

1% chlorhexidine digluconate and aqueous extract of miswak are equally effective against S. mutans and S. sobrinus. Miswak can be used as an alternative herbal antimicrobial that can be incorporated in anhydrous GIC.

How to cite this article

Kalpavriksha AJ, Siddaiah SB, Bilichodmath S, et al. Comparative Evaluation of Antibacterial Effect of GIC Containing Chlorhexidine and Miswak on Streptococcus mutans and Streptococcus sobrinus in Early Childhood Caries Children: A PCR Study. Int J Clin Pediatr Dent 2021;14(2):229–234.

Antimicrobial activity of biosynthesized silver nanoparticles, amoxicillin, and glass-ionomer cement againstStreptococcus mutansandStaphylococcus aureus

Background. The development of dental caries is associated with various microorganisms and secondary caries formation is the main cause of restorations failure. The advice for restorative dental materials that have antimicrobial properties has stimulated the introduction of materials containing different antibacterial agents.Objectives. The present study has been designed to synthesize silver nanoparticles (AgNPs) and incorporate AgNPs and amoxicillin into glass ionomer cement (GIC) to synergize its effect on oral microbes. The effect of the added antimicrobial agents on compressive strength (CS) of GIC was also evaluated.Material and methods. Biosynthesis of AgNPs was done usingCupressus macrocarpaextract and AgNPs were characterized. A total of 120 disc-shaped specimens were prepared and classified into 4 main groups where Group A includes conventional GIC, Groups B and C include GIC with AgNPs or amoxicillin, respectively, while Group D included GIC with both AgNPs and amoxicillin. Each group was tested for the antimicrobial activity against bothStreptococcus mutans(S. mutans) andStaphylococcus aureus(S. aureus). The distribution of biofilm was examined via a scanning electron microscope. The CS of the tested material was measured using a Material Test System.Results. The UV-visible spectrum showed a peak of 429 nm. Transmission electron microscopy, x-ray diffraction pattern and Fourier transform infrared analysis confirmed the formation of AgNPs with spherical to oblong polydispersed particles of diameter in the range of 13.5-25.8 nm. The maximum inhibitory zone was recorded for group D against both tested bacteria with a mean of 29 mm at first 24 h period to 15 mm at three weeks and showed antimicrobial rate 92.2% and 92.56%, against both strains, respectively. Additionally, group D disintegrated the structure ofS. aureusbiofilm and even kill bacteria in the biofilms. The addition of AgNPs and amoxicillin caused an insignificant effect on CS of GIC.Conclusion.TheAgNPs showed a synergistic effect in combination with amoxicillin and GIC dental restorative material against studied microorganisms. The agents can be safely added with minimal effect on the mechanical properties of the original cement.

Factors affecting success rate of atraumatic restorative treatment (ART) restorations in children: A systematic review and meta-analysis

OBJECTIVES

Aim of this systematic review was to summarize the factors that affect the success rate of atraumatic restorative treatment (ART) restorations in children.

DATA/SOURCES

Two independent reviewers conducted a literature search in the databases PubMed, Medline and Web of Science until October 2019 with no initial time limit. Articles reporting on clinical outcomes of ART restorations placed in children were included.

STUDY SELECTION

A total of 67 articles were included in this review reporting on clinical outcomes of ART restorations placed in children in 47 studies. The overall estimated success rate and 95 % confidence interval (CI) of ART restorations were 0.71 (0.65-0.77) and 0.67 (0.56-0.78) at the 12-month and the 24-month follow-up, respectively. Operator was one of the significant factors associated with the success rate of ART restorations. ART restorations placed by dental students/therapists had a significantly lower success rate compared with those placed by dentists. Besides, type of restoration (single-surface vs. multiple-surface restoration) was also associated with the success rate of ART restorations. Other factors including dentition, restorative material, clinical setting, and moisture control method had no significant influence on the success rate of ART restorations in children.

CONCLUSION

It is concluded that ART approach can be used to manage cavitated caries lesions in children. Operator and type of restoration are significant factors influencing the success rate of ART restorations.

CLINICAL SIGNIFICANCE

This study provides valuable information on the factors that affect success rate of ART restorations in children, which helps clinicians to make informed decisions on provision of ART restorations in children.

Bioadhesion in the oral cavity and approaches for biofilm management by surface modifications

BACKGROUND

All soft and solid surface structures in the oral cavity are covered by the acquired pellicle followed by bacterial colonization. This applies for natural structures as well as for restorative or prosthetic materials; the adherent bacterial biofilm is associated among others with the development of caries, periodontal diseases, peri-implantitis, or denture-associated stomatitis. Accordingly, there is a considerable demand for novel materials and coatings that limit and modulate bacterial attachment and/or propagation of microorganisms.

OBJECTIVES AND FINDINGS

The present paper depicts the current knowledge on the impact of different physicochemical surface characteristics on bioadsorption in the oral cavity. Furthermore, it was carved out which strategies were developed in dental research and general surface science to inhibit bacterial colonization and to delay biofilm formation by low-fouling or "easy-to-clean" surfaces. These include the modulation of physicochemical properties such as periodic topographies, roughness, surface free energy, or hardness. In recent years, a large emphasis was laid on micro- and nanostructured surfaces and on liquid repellent superhydrophic as well as superhydrophilic interfaces. Materials incorporating mobile or bound nanoparticles promoting bacteriostatic or bacteriotoxic properties were also used. Recently, chemically textured interfaces gained increasing interest and could represent promising solutions for innovative antibioadhesion interfaces. Due to the unique conditions in the oral cavity, mainly in vivo or in situ studies were considered in the review.

CONCLUSION

Despite many promising approaches for modulation of biofilm formation in the oral cavity, the ubiquitous phenomenon of bioadsorption and adhesion pellicle formation in the challenging oral milieu masks surface properties and therewith hampers low-fouling strategies.

CLINICAL RELEVANCE

Improved dental materials and surface coatings with easy-to-clean properties have the potential to improve oral health, but extensive and systematic research is required in this field to develop biocompatible and effective substances.

Chlorhexidine to improve the survival of ART restorations: A systematic review and meta-analysis

OBJECTIVES

Our aim was to systematically assess the efficacy of chlorhexidine (CHX) as a cavity pre-treatment or restoration mix-in on the survival of ART restorations.

DATA

We included randomized controlled trials that assessed the effect of cavity pretreatment with CHX or the restoration mix-in of CHX on the survival of ART restorations (test group) versus a similar restorative approach without CHX. Risk of bias was assessed using Cochrane's randomized trial quality assessment Tool (RoB 2.0). Random-effects meta-analysis was conducted, with mean Odds Ratios and 95 % confidence intervals (OR, 95 % CI) as effect estimates. The certainty of the evidence was assessed according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

SOURCES

Medline, Web of Science, Cochrane Central were searched. Eligible studies were in- or excluded and data extracted for included studies by two reviewers independently.

STUDY SELECTION

Four studies with 261 patients (mean age 3.8-14.6 years) and 467 ART restorations were included. All studies showed some concerns about the risk of bias. Three studies involving a total of 167 restorations in the CHX group and 188 restorations in the control group, followed up for one year, were submitted to meta-analysis. There were no significant differences between CHX vs. control (OR = 0.79, 95 % CI [0.26, 2.40], P = 0.68, I² = 3%, P = 0.35). The strength of the evidence was estimated as low.

CONCLUSIONS

Based on very limited data, CHX pre-treatment or restoration mix-in did not have any significant benefit for survival of ART restorations.

CLINICAL SIGNIFICANCE

There is a lack of evidence regarding the influence of chlorhexidine on the survival of ART restorations. Our results revealed that there was no significant difference in the survival of ART restorations when CHX was used as a cavity pre-treatment or mix-in.

Antimicrobial properties, compressive strength and fluoride release capacity of essential oil-modified glass ionomer cements-an in vitro study

OBJECTIVES

This study was designed to investigate the antimicrobial properties, compressive strength and fluoride release capacities of high-viscous glass ionomer cements (GICs) after incorporation of cinnamon and thyme essential oils.

MATERIALS AND METHODS

Experimental-modified GICs were prepared by incorporation of thyme and cinnamon essential oils into the liquid phase of the cement at 5 and 10% v/v. Antimicrobial activity against selected microorganisms (Streptococcus mutans and Candida albicans) was done using direct contact test. Compressive strength of the four new formulations and control group was tested using a universal testing machine while fluoride ion release was measured by ion-selective electrode at 1, 7, 14 and 28 days. Data analysis and comparisons between groups were performed using factorial and one-way ANOVA and Tukey's tests.

RESULTS

All newly formulated GICs exhibited significantly higher inhibitory effects against both Streptococcus mutans and Candida albicans growth when compared to conventional GIC (p < 0.05). Compressive strength of 5% cinnamon-modified GIC (MPa = 160.32 ± 6.66) showed no significant difference when compared with conventional GIC (MPa = 165.7 ± 5.769) (p value > 0.05). Cumulative fluoride-releasing pattern at days 7, 14, and 28 were 10% cinnamon-GIC > 5% thyme-GIC > 5% cinnamon-GIC > 10% thyme GIC > conventional GIC.

CONCLUSIONS

Incorporation of 5% cinnamon oil into glass ionomer resulted in better antimicrobial effects against S. mutans and C. albicans and increased fluoride-release capacity without jeopardizing its compressive strength.

CLINICAL RELEVANCE

The 5% cinnamon-modified GIC appears to be a promising alternative restorative material in ART technique.

Management of Streptococcus mutans-Candida spp. Oral Biofilms' Infections: Paving the Way for Effective Clinical Interventions

Oral diseases are considered the most common noncommunicable diseases and are related to serious local and systemic disorders. Oral pathogens can grow and spread in the oral mucosae and frequently in biomaterials (e.g., dentures or prostheses) under polymicrobial biofilms, leading to several disorders such as dental caries and periodontal disease. Biofilms harbor a complex array of interacting microbes, increasingly unapproachable to antimicrobials and with dynamic processes key to disease pathogenicity, which partially explain the gradual loss of response towards conventional therapeutic regimens. New drugs (synthesized and natural) and other therapies that have revealed promising results for the treatment or control of these mixed biofilms are presented and discussed here. A structured search of bibliographic databases was applied to include recent research. There are several promising new approaches in the treatment of Candida spp.-Streptococcus mutans oral mixed biofilms that could be clinically applied in the near future. These findings confirm the importance of developing effective therapies for oral Candida-bacterial infections.

Trans,trans-farnesol, an antimicrobial natural compound, improves glass ionomer cement properties

A series of experiments were conducted to characterize a novel restorative material. We explored the effect on biological, physical and chemical properties of glass ionomer cement (GIC) adding-the naturally occurring tt-farnesol (900 mM). Two groups were accomplished for all assays: GIC+tt-farnesol and GIC (control). Biological assays: 1) agar diffusion against some cariogenic bacteria; 2) S. mutans biofilm formation and confocal laser scanning microscopy-CLSM. 3) gtfB, gtfC, gtfD, gbpB, vicR, and covR expression; 4) MTT and microscopic morphology. Physical properties assays: 1) roughness; 2) hardness; 3) compressive strength and 4) diametral tensile strength. Chemical assay: Raman spectroscopy. The adding of tt-farnesol to GIC led to larger zones of inhibition (p<0.05), biofilms with a short-term reduction in bacterial viability but similar biomass (p>0.05). Polysaccharides levels increased over time, similarly over groups (p>0.05). Viable and non-viable S. mutans were seen on the specimens’ surface by CLSM but their virulence was not modulated by tt-farnesol. The tt-farnesol increased the HaCaT cell viability without impact on compressive and diametral tensile strength and roughness although the hardness was positively affected (p<0.05). Raman confirmed the presence of tt-farnesol. The incorporation of tt-farnesol into GIC inhibited the growth of cariogenic bacteria but had a little effect on the composition, structure and physiology of the biofilm matrices. Also, the tt-farnesol increased the hardness and the biocompatibility of the GIC, not influencing negatively other physical properties of the restorative material.

Survival of occlusal ART restorations using high-viscosity glass-ionomer with and without chlorhexidine: A 2-year split-mouth quadruple-blind randomized controlled clinical trial

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Comparing the survival of HVGICs (with and without CHX) using ART criteria.

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Comparing the survival of HVGICs (with and without CHX) using FDI criteria.

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Compare the effect of the two restorations on caries development.

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No significant difference in the survival percentages between the two types of HVGICs.

•

The addition of CHX to the HVGIC is not recommended.

The study question was whether the use of high-viscosity glass-ionomer with chlorhexidine (HVGIC/CHX) for the Atraumatic Restorative Treatment (ART) prepared cavities could achieve a higher restoration survival percentage and be more effective for preventing dentine carious lesions adjacent to the restoration than the use of HVGIC without CHX. The study followed a split-mouth, quadruple-blind, randomized controlled clinical design and lasted 2 years. Patients with at least two small- to medium-sized occlusal cavities were included. The occlusal cavities were prepared according to the ART method and restored with HVGIC/CHX (test) and HVGIC (control). A replica of all restorations available and digital photographs were fabricated at baseline and after 0.5, 1, 1.5 and 2 years and evaluated by two examiners using the ART and Federation Dentaire International (FDI) restoration assessment criteria. Survival curves were constructed using the Kaplan-Meier method, and the log-rank test was used to test for significance between the survival percentages. A total of 100 subjects with an average age of 14.4 years participated. According to the ART restoration assessment criteria, the 2-year survival percentages of ART/HVGIC/CHX (96.8%) and ART/HVGIC (94.8%) did not differ significantly and no significant difference was found between the test (97.9%) and control (96.9%) groups according to the FDI restoration assessment criteria. Eight and five occlusal restorations failed according to the ART and FDI restoration criteria, respectively. No dentine carious lesions along the restoration margin were observed. The 2-year survival of ART restorations in both groups was high. The development of carious dentine lesions adjacent to the restoration was not observed in either treatment group. There is no evidence for modifying HVGIC by incorporating chlorhexidine in order to prevent dentine carious lesion development or to improve the survival of ART restorations in occlusal surfaces in permanent teeth. HVGIC without chlorhexidine can be used successfully to restore occlusal ‘ART-prepared’ cavities in permanent teeth.

The effect of antimicrobial additives on the properties of dental glass-ionomer cements: a review

Aim: The aim of this article is to review the literature on the use of antimicrobial additives in glass-ionomer dental cements. Method: An electronic search between 1987 and the end of 2017 was performed using PubMed, Web of Science and Google search engines with the terms glass-ionomer, glass polyalkenoate, antibacterial and antimicrobial as the key words. The search was refined by excluding the majority of references concerned with cement antimicrobial properties only. Extra papers already known to the authors were added to those considered. Results: A total of 92 relevant articles have been cited in the review of which 55 are specifically concerned with the enhancement of antibacterial properties of glass-ionomers, both conventional and resin-modified, with additives. In addition, information is included on the uses of glass-ionomers and the biological properties of the antibacterial additives employed. There are several reports that show that additives are typically released by diffusion, and that a high proportion is usually left behind, trapped in the cement. Additives generally increase setting times of cements, and reduce mechanical properties. However, smaller amounts of additive have only slight effects and the longer-term durability of cements appears unaffected. Conclusion: Modified glass-ionomer cements seem to be acceptable for clinical use, especially in the Atraumatic Restorative Treatment (ART) technique.

Glass ionomer cements with milled, dry chlorhexidine hexametaphosphate filler particles to provide long-term antimicrobial properties with recharge capacity

OBJECTIVE

Glass ionomer cements (GICs) are a versatile material, offering the opportunity for ion exchange with the oral environment. The aim of this study was to develop a GIC that delivers a controlled, rechargeable dose of chlorhexidine (CHX) over an extended period without compromising mechanical properties.

METHODS

GICs were supplemented with finely milled particles of chlorhexidine hexametaphosphate (CHX-HMP). CHX release into artificial saliva was measured over 660 days, and recharge with CHX and CHX-HMP was investigated. Mechanical properties were investigated, and an agar diffusion test was carried out to assess antimicrobial properties using Streptococcus mutans and Scardovia wiggsiae.

RESULTS

Dose-dependent CHX release was observed, and this was ongoing at 660 days. Compared with related studies of GICs containing CHX-HMP, the fine, dry particles resulted in fewer adverse effects on mechanical properties, including tensile, compressive and biaxial flexural strength, with 1% CHX-HMP GICs indistinguishable from control specimens. The GICs could be recharged with CHX using both a conventional CHX digluconate solution comparable to commercial mouthrinses, and a suspension of CHX-HMP of equivalent concentration. Recharging with CHX digluconate increased subsequent CHX release by 50% compared with no recharge, and recharging with CHX-HMP increased subsequent CHX release by 100% compared with no recharge. The GICs inhibited growth of St. mutans and Sc. wiggsiae in a simple agar diffusion model.

SIGNIFICANCE

These materials, which provide sustained CHX release over clinically relevant timescales, may find application as a restorative material intended to inhibit secondary caries as well as in temporary restorations and fissure sealants.

Clinical Evaluation of Microhybrid Composite and Glass lonomer Restorative Material in Permanent Teeth

AIM

The aim of this study was to clinically compare glass ionomer cement (GIC) with microhybrid composite resin used in class I cavities on permanent teeth over a period of 9 months.

MATERIALS AND METHODS

A total of 40 teeth with class I cavities were divided into two groups (n = 20) and restored with GIC (EQUIA; GC) and microhybrid resin composite (Amelogen Plus; Ultradent). Restorations were evaluated at ×4.5 magnification using the United States Public Health Service (USPHS) criteria every 3 months. Statistical analysis was performed using the Fisher's exact test (a < 0.05).

RESULTS

The data obtained reported no statistical significance difference between both groups in regard to anatomical shape, color, postoperative sensitivity, secondary caries, material handling, adaptation, and marginal staining.

CONCLUSION

The results of this clinical study showed that GIC (EQUIA; GC) can be used for the restoration of permanent teeth and may be more appropriate for certain clinical situations than the resin composite material.

CLINICAL SIGNIFICANCE

EQUIA (GIC) is a viable alternative to resin composite in restoring class I cavities in permanent teeth.