Synergistic antimicrobial potential of EGCG and fosfomycin against biofilms associated with endodontic infections.

OBJECTIVE: This study aimed to evaluate the cytotoxicity and synergistic effect of epigallocatechin gallate (EGCG) and fosfomycin (FOSFO) on biofilms of oral bacteria associated with endodontic infections. METHODOLOGY: This study determined minimum inhibitory and bactericidal concentration (MIC/MBC) and fractionated inhibitory concentration (FIC) of EGCG and FOSFO against Enterococcus faecalis, Actinomyces israelii, Streptococcus mutans, and Fusobacterium nucleatum. Monospecies and multispecies biofilms with those bacteria formed in polystyrene microplates and in radicular dentin blocks of bovine teeth were treated with the compounds and control chlorhexidine (CHX) and evaluated by bacterial counts and microscopy analysis. Toxicity effect of the compounds was determined on fibroblasts culture by methyl tetrazolium assays. RESULTS: The combination of EGCG + FOSFO demonstrated synergism against all bacterial species, with an FIC index ranging from 0.35 to 0.5. At the MIC/FIC concentrations, EGCG, FOSFO, and EGCG+FOSFO were not toxic to fibroblasts. EGCG+FOSFO significantly reduced monospecies biofilms of E. faecalis and A. israelli, whereas S. mutans and F. nucleatum biofilms were eliminated by all compounds. Scanning electron microscopy of multispecies biofilms treated with EGCG, EGCG+FOSFO, and CHX at 100x MIC showed evident biofilm disorganization and substantial reduction of extracellular matrix. Confocal microscopy observed a significant reduction of multispecies biofilms formed in dentin tubules with 84.85%, 78.49%, and 50.6% of dead cells for EGCG+FOSFO, EGCG, and CHX at 100x MIC, respectively. CONCLUSION: EGCG and fosfomycin showed a synergistic effect against biofilms of oral pathogens related to root canal infections without causing cytotoxicity.

Understanding the Predictive Potential of the Oral Microbiome in the Development and Progression of Early Childhood Caries.

BACKGROUND: Early childhood caries (ECC) is the most common chronic disease in young children and a public health problem worldwide. It is characterized by the presence of atypical and fast progressive caries lesions. The aggressive form of ECC, severe early childhood caries (S-ECC), can lead to the destruction of the whole crown of most of the deciduous teeth and cause pain and sepsis, affecting the child's quality of life. Although the multifactorial etiology of ECC is known, including social, environmental, behavioral, and genetic determinants, there is a consensus that this disease is driven by an imbalance between the oral microbiome and host, or dysbiosis, mediated by high sugar consumption and poor oral hygiene. Knowledge of the microbiome in healthy and caries status is crucial for risk monitoring, prevention, and development of therapies to revert dysbiosis and restore oral health. Molecular biology tools, including next-generation sequencing methods and proteomic approaches, have led to the discovery of new species and microbial biomarkers that could reveal potential risk profiles for the development of ECC and new targets for anti-caries therapies. This narrative review summarized some general aspects of ECC, such as definition, epidemiology, and etiology, the influence of oral microbiota in the development and progression of ECC based on the current evidence from genomics, transcriptomic, proteomic, and metabolomic studies and the effect of antimicrobial intervention on oral microbiota associated with ECC. CONCLUSION: The evaluation of genetic and proteomic markers represents a promising approach to predict the risk of ECC before its clinical manifestation and plan efficient therapeutic interventions for ECC in its initial stages, avoiding irreversible dental cavitation.

Synergistic antimicrobial potential of EGCG and fosfomycin against biofilms associated with endodontic infections

Abstract Objective This study aimed to evaluate the cytotoxicity and synergistic effect of epigallocatechin gallate (EGCG) and fosfomycin (FOSFO) on biofilms of oral bacteria associated with endodontic infections. Methodology This study determined minimum inhibitory and bactericidal concentration (MIC/MBC) and fractionated inhibitory concentration (FIC) of EGCG and FOSFO against Enterococcus faecalis, Actinomyces israelii, Streptococcus mutans, and Fusobacterium nucleatum. Monospecies and multispecies biofilms with those bacteria formed in polystyrene microplates and in radicular dentin blocks of bovine teeth were treated with the compounds and control chlorhexidine (CHX) and evaluated by bacterial counts and microscopy analysis. Toxicity effect of the compounds was determined on fibroblasts culture by methyl tetrazolium assays. Results The combination of EGCG + FOSFO demonstrated synergism against all bacterial species, with an FIC index ranging from 0.35 to 0.5. At the MIC/FIC concentrations, EGCG, FOSFO, and EGCG+FOSFO were not toxic to fibroblasts. EGCG+FOSFO significantly reduced monospecies biofilms of E. faecalis and A. israelli, whereas S. mutans and F. nucleatum biofilms were eliminated by all compounds. Scanning electron microscopy of multispecies biofilms treated with EGCG, EGCG+FOSFO, and CHX at 100x MIC showed evident biofilm disorganization and substantial reduction of extracellular matrix. Confocal microscopy observed a significant reduction of multispecies biofilms formed in dentin tubules with 84.85%, 78.49%, and 50.6% of dead cells for EGCG+FOSFO, EGCG, and CHX at 100x MIC, respectively. Conclusion EGCG and fosfomycin showed a synergistic effect against biofilms of oral pathogens related to root canal infections without causing cytotoxicity.

Microbiological Properties and Cytotoxicity of PNVCL Hydrogels Containing Flavonoids as Intracanal Medication for Endodontic Therapy.

This study aimed to evaluate the cytotoxicity and microbiological properties of poly (N-vinylcaprolactam)-PNVCL hydrogels containing flavonoids as intracanal medication for endodontic therapy. Antimicrobial activity of ampelopsin (AMP), isoquercitrin and rutin was determined against Enterococcus faecalis, Actinomyces israelii, Lactobacillus casei, Streptococcus mutans, and Fusobacterium nucleatum by the microdilution method. After synthesis and characterization by rheology, PNVCL hydrogels were loaded with AMP and controls calcium hydroxide (CH) and chlorhexidine (CHX), and determined the compounds release profile. PNVCL+AMP, PNVCL+CH, PNVCL+CHX were evaluated on multi-species biofilms and analyzed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Cytotoxicity was determined after fibroblasts exposure to serial dilutions of AMP and PNVCL hydrogel extracts. AMP was effective against all of the bacteria tested, especially against S. mutans, A. israelli and F. nucleatum. SEM and CLSM analysis showed that PNVCL + AMP caused a significant decrease and disorganization of multi-species biofilms and reduction of intracanal viable cells, superior to the other groups. AMP affected fibroblast viability at concentrations above 0.125 mg/mL, and extracts of PNVCL+AMP showed low cytotoxicity. In conclusion, PNVCL containing AMP demonstrated cytocompatibility and potent effect against multi-species biofilms and could be potential intracanal medication for endodontic purposes.

Antibiofilm and cytotoxic effect of 3,3'-dihydroxycurcumin (DHC) as photosensitizer agent in antimicrobial photodynamic therapy for endodontic purposes.

BACKGROUND: Curcuminoids have been designed not only to improve chemical and metabolic stability of curcumin (CUR), but also to increase its antimicrobial activity, without effecting its ability as photosensitizer agent in antimicrobial photodynamic therapy (aPDT) with light emitting diode (LED). This study evaluated the antimicrobial and antibiofilm action of curcumin analog DHC (or 3,3'-dihydroxycurcumin), submitted or not to LED irradiation, on microorganisms of endodontic importance and its influence on fibroblasts viability. METHODS: DHC was synthetized by modified Pablon's methodology and the experiments were conducted under irradiation or not with indium gallium nitride-based LED (440-480nm, 100 mW/cm2, 0.78 cm2,60 s). The antimicrobial activity of CUR and DHC were determined by the Minimum Inhibitory and Bactericidal Concentration assays against Gram-positive and Gram-negative bacteria and the effect of both compounds on fibroblast viability was tested using colorimetric assays. They were also evaluated on 72h and 7days single-species biofilms and on 14 days multispecies biofilms formed inside dentin tubules by bacterial colonies counts and confocal microscopy, respectively. Data were analyzed statistically considering p<0.05. RESULTS: DHC had bactericidal effect against all bacteria tested higher than CUR, in planktonic conditions. CUR and DHC (at 39 and 19 µg/mL, respectively) were cytocompatible and LED irradiation reduced fibroblast viability, regardless of compound. CUR and DHC reduced the growth of single-species biofilms and the effect of aPDT was bacteria dependent. DHC reduced more than 70% of microorganisms from multispecies biofilms, superior to CUR effect. CONCLUSIONS: DHC showed low cytotoxicity and antibiofilm effect similar to curcumin, when submitted or not to aPDT, and could be further explored as a bioactive compound for endodontic purposes.

Cytotoxicity and effects of curcumin and cinnamaldehyde hybrids on biofilms of oral pathogens.

The objective of the study was to evaluate the cytotoxicity and effect of curcumin-cinnamaldehyde hybrids (CCHs) on the biofilm of oral pathogens. Of the 18 hybrids tested, nine had an inhibitory effect on at least one of the bacterial species tested, with minimal inhibitory and bactericidal concentrations ranging from 9 to 625 µg ml-1. CCH 7 promoted a potent inhibitory effect against all the bacterial species tested and better compatibility than chlorhexidine (CHX). CCH 7 also presented a similar or improved effect over that of CHX, causing a reduction in bacterial metabolism and viability in single and dual-species biofilms. CCH 7 reduced by 86% and 34% the viability of multispecies biofilms formed by collection and clinical strains. It can be concluded that CCH 7 was cytocompatible at the minimal inhibitory concentration, presented anti-biofilm action against oral pathogens, and could act as an antimicrobial agent for application in endodontics.

Efeito de análogos de curcumina, irradiados ou não por LED, como agentes antimicrobianos e indutores de proliferação e migração celular / Effect of curcumin analogues, irradiated or not by LED, as antimicrobial agents and inducers of cell proliferation and migration

O tratamento endodôntico de dentes permanentes jovens com infecções pulpares/periapicais antes de completar a rizogênese ainda é um desafio para a Endodontia e a Odontopediatria. Relatos científicos têm mostrado que a curcumina (CUR), um fitoquímico polifenólico, apresenta diversas propriedades terapêuticas, entre as quais, amplo espectro de ação antimicrobiana e a capacidade de induzir a proliferação e migração celular. Além disso, devido à sua capacidade excitatória na presença de luz, a CUR também tem sido utilizada como fotossensibilizante em terapia fotodinâmica associada ao LED (light emitting diode), promovendo aumento dos seus efeitos biológicos. Uma forma de aumentar seu potencial terapêutico e reduzir algumas limitações do uso da CUR é a síntese de análogos a partir de pequenas modificações químicas na estrutura original, entretanto, mantendo sua capacidade fotossensibilizante. O objetivo desse estudo foi avaliar a ação antimicrobiana e antibiofilme de análogos de curcumina sob a influência ou não do LED sobre microrganismos de interesse endodôntico e sua influência sobre a viabilidade, proliferação e migração de fibroblastos da linhagem L-929. Uma série de compostos análogos de CUR (PCR-4 H, PCR-3 OH, PCR-4 OH, PCR-3 OCH3, PCR-4 OCH3, PCR-3 acetil, PCR-4 acetil) foram sintetizados pela metodologia de Pabon. A atividade antimicrobiana da CUR e seus análogos foi determinada pelo ensaio de Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM) sobre Streptococcus mutans, Lactobacillus casei, Actinomyces israelii, Enterococcus faecalis e Fusobacterium nucleatum, sob a ação ou não do LED InGaN (nitreto de gálio e índio, com potência de saída de 100 mW/cm², ponta do LED com área de 0,78 cm², 60 s). A curcumina e seu análogo com melhor efeito antimicrobiano (PCR-3 OH) foi avaliado sobre o biofilme inicial (72h) e maduro (1 semana) dessas espécies em microplacas e sobre biofilmes multiespécies formados em túbulos dentinários por contagem das UFC/mL e por microscopia confocal, respectivamente, sob ação ou não do LED. Também foram avaliados quanto à citotoxicidade e a capacidade de induzir proliferação e migração em fibroblastos, por meio de ensaios de metiltetrazólio, azul de tripan e azul de Coomassie, respectivamente. Os dados foram avaliados estatisticamente (p<0,05). Dos 7 análogos de curcumina sintetizados, PCR-3 OH foi o único composto que apresentou atividade bactericida quando testado sobre as bactérias de interesse endodôntico selecionadas. Seu efeito foi potencializado na presença do LED, variando entre as espécies bacterianas. A curcumina teve efeito bactericida para as espécies S. mutans, A. israelii, L. casei e F. nucleatum, e em algumas delas, foi independente do LED. Ambos os compostos reduziram o crescimento dos biofilmes iniciais ou maduros, independente do LED. Entretanto, quando irradiados, o efeito dos compostos variou de acordo com a espécie bacteriana, sendo que A. israelii e S. mutans foram os mais afetados. Ambos os compostos reduziram significativamente os biofilmes multiespécies quando comparados ao controle sem tratamento, sendo que melhor efeito foi observado para PCR-3 OH. A curcumina foi considerada citocompatível a partir de 0,039µg/mL e PCR-3 OH a partir de 0,019 µg/mL. Houve redução significativa na viabilidade celular quando os compostos foram irradiados com LED nas concentrações 0,039 e 0,019 µg/mL. O LED, dentro dos parâmetros testados, reduziu significativamente a viabilidade, a proliferação e a migração celular, independente do composto ou tempo de exposição. Conclui-se que PCR-3 OH apresentou atividade bactericida e sobre biofilmes simples e multiespécies de bactérias de interesse endodôntico superior à CUR, principalmente sob ação do LED. Entretanto, sua citocompatiblidade foi inferior à da CUR. A presença do LED afetou a viabilidade, proliferação e migração dos fibroblastos, mostrando que os parâmetros utilizados para fins antimicrobianos não foram adequados para aplicação em células eucarióticas(AU)

Endodontic treatment of young permanent teeth with pulp / periapical infections before completing rhizogenesis is still a challenge for Endodontics and Pediatric Dentistry. Scientific reports have shown that curcumin (CUR), a polyphenolic phytochemical, has several therapeutic properties, including a broad spectrum of antimicrobial action and the ability to induce cell proliferation and migration. In addition, due to its excitatory capacity in the presence of light, CUR has also been used as a photosensitizer in photodynamic therapy associated with LED (light emitting diode), promoting an increase in its biological effects. One way to increase its therapeutic potential and reduce some limitations of the use of CUR is the synthesis of analogues from small chemical modifications in the original structure, however, maintaining its photosensitizing capacity. The aim of this study was to evaluate the antimicrobial and antibiofilm action of curcumin analogues under the influence or not of LED on microorganisms of endodontic interest and their influence on the viability, proliferation and migration of L-929 fibroblasts. A series of CUR analog compounds (PCR-4 H, PCR-3 OH, PCR-4 OH, PCR-3 OCH3, PCR-4 OCH3, PCR-3 acetyl, PCR-4 acetyl) were synthesized by Pabon's methodology. The antimicrobial activity of CUR and its analogs was determined by the Minimum Concentration Inhibitory (CIM) and Minimum Bactericidal Concentration (CBM) assay on Streptococcus mutans, Lactobacillus casei, Actinomyces israelii, Enterococcus faecalis and Fusobacterium nucleatum, with or without the InGaN LED (gallium and indium nitride, with output power of 100 mW / cm², LED tip with an area of 0.78 cm², 60 sec). Curcumin and its analog with the best antimicrobial effect (PCR-3 OH) were evaluated on the initial (72h) and mature (1 week) biofilm of these species in microplates and on multispecies biofilms formed in dentinal tubules by counting CFU / mL and by confocal microscopy, respectively, under the action or not of the LED. They were also evaluated for cytotoxicity and the ability to induce proliferation and migration in fibroblasts, using methyltetrazolium, trypan blue and Coomassie blue assays, respectively. The data were evaluated statistically (p <0.05). Of the 7 curcumin analogues synthesized, PCR-3 OH was the only compound that showed bactericidal activity when tested on selected bacteria of endodontic interest. Its effect was enhanced in the presence of LED, varying between bacterial species. Curcumin had a bactericidal effect for the species S. mutans, A. israelii, L. casei and F. nucleatum, and in some of them, it was independent of the LED. Both compounds reduced the growth of the initial or mature biofilms, regardless of the LED. However, when irradiated, the effect of the compounds varied according to the bacterial species, with A. israelii and S. mutans being the most affected. Both compounds significantly reduced multispecies biofilms when compared to the untreated control, with the best effect being observed for PCR-3 OH. Curcumin was considered cytocompatible from 0.039 µg / mL and PCR-3 OH from 0.019 µg / mL. There was a significant reduction in cell viability when the compounds were irradiated with LED at concentrations of 0.039 and 0.019 µg / mL. The LED, within the parameters tested, significantly reduced cell viability, proliferation and migration, regardless of the compound or time of exposure. It is concluded that PCR-3 OH showed bactericidal activity and on simple and multispecies biofilms of bacteria of endodontic interest superior to CUR, mainly under the action of LED. However, its cytocompatibility was lower than that of the CUR. The presence of the LED affected the viability, proliferation and migration of fibroblasts, showing that the parameters used for antimicrobial purposes were not suitable for application in eukariotic cells(AU)

Incorporation of chlorhexidine and nano-sized sodium trimetaphosphate into a glass-ionomer cement: Effect on mechanical and microbiological properties and inhibition of enamel demineralization.

OBJECTIVE: To evaluate the antimicrobial/antibiofilm and mechanical properties, and the effect on enamel demineralization of a resin-modified GIC (RMGIC) containing CHX and nano-sized sodium trimetaphosphate (TMP). METHODS: RMGIC was associated with CHX (1.25 or 2.5%) and/or TMP (7 or 14%). Antimicrobial and antibiofilm activity were assessed using agar diffusion test and evaluation of biofilm metabolism, respectively. In addition, fluoride (F) and TMP releases as well as the diametral tensile (DTS) and compressive (CS) strength were determined. The percentage of mineral loss (%SH), integrated loss of subsurface hardness (ΔKHN) and enamel F concentrations were also evaluated. RESULTS: RMGICs containing CHX associated or not with TMP presented higher inhibition zones and effect on S. mutans biofilm. A reduction on CS was observed only for RMGIC + 2.5%CHX and on DTS for RMGIC + 2.5%CHX + 14%TMP. The highest F and TMP releases and lowest %SH and ΔKHN values were detected for RMGIC + 1.25%CHX + 14%TMP and RMGIC + 2.5%CHX + 14%TMP. Higher enamel F concentrations were observed for TMP groups. CONCLUSION: 1.25%CHX and 14%TMP increased antimicrobial/antibiofilm action and the ability to prevent enamel demineralization, with minimal effect on the mechanical properties of RMGIC. CLINICAL SIGNIFICANCE: RMGIC containing CHX and TMP is an alternative material for patients at high risk for dental caries and can be indicated for low-stress regions or provisional restorations.

Doxycycline-containing glass ionomer cement for arresting residual caries: an in vitro study and a pilot trial.

In a previous study, we demonstrated that the incorporation of doxycycline hyclate (DOX) into resin-modified glass ionomer cement (RMGIC) inhibited important cariogenic microorganisms, without modifying its biological and mechanical characteristics. In this study, we keep focused on the effect of that experimental material as a potential therapy for arresting residual caries by analyzing other in vitro properties and conducting a pilot clinical trial assessing the in vivo effect of DOX-containing RMGIC on residual mutans streptococci after partial carious removal in primary molars. Specimens of the groups RMGIC (control); RMGIC + 1.5% DOX; RMGIC + 3% DOX; and RMGIC + 4.5% DOX were made to evaluate the effect of DOX incorporation on surface microhardness and fluoride release of RMGIC and against biofilm of Streptococcus mutans. Clinical intervention consisted of partial caries removal comparing RMGIC and RMGIC + 4.5% DOX as lining materials. After 3 months, clinical and microbiologic evaluations were performed. Data were submitted to ANOVA/Tukey or Wilcoxon/Mann-Whitney set as α=0.05. Fluoride release and surface microhardness was not influenced by the incorporation of DOX (p>0.05). There was a significant reduction of S. mutans biofilm over the material surface with the increase of DOX concentration. After clinical trial, the remaining dentin was hard and dry. Additionally, mutans streptococci were completely eliminated after 3 months of treatment with RMGIC + 4.5% DOX. The incorporation of DOX provided better antibiofilm effect, without jeopardizing fluoride release and surface microhardness of RMGIC. This combination also improved the in vivo shortterm microbiological effect of RMGIC after partial caries removal.

Doxycycline-containing glass ionomer cement for arresting residual caries: an in vitro study and a pilot trial

Abstract In a previous study, we demonstrated that the incorporation of doxycycline hyclate (DOX) into resin-modified glass ionomer cement (RMGIC) inhibited important cariogenic microorganisms, without modifying its biological and mechanical characteristics. In this study, we keep focused on the effect of that experimental material as a potential therapy for arresting residual caries by analyzing other in vitro properties and conducting a pilot clinical trial assessing the in vivo effect of DOX-containing RMGIC on residual mutans streptococci after partial carious removal in primary molars. Specimens of the groups RMGIC (control); RMGIC + 1.5% DOX; RMGIC + 3% DOX; and RMGIC + 4.5% DOX were made to evaluate the effect of DOX incorporation on surface microhardness and fluoride release of RMGIC and against biofilm of Streptococcus mutans. Clinical intervention consisted of partial caries removal comparing RMGIC and RMGIC + 4.5% DOX as lining materials. After 3 months, clinical and microbiologic evaluations were performed. Data were submitted to ANOVA/Tukey or Wilcoxon/Mann-Whitney set as α=0.05. Fluoride release and surface microhardness was not influenced by the incorporation of DOX (p>0.05). There was a significant reduction of S. mutans biofilm over the material surface with the increase of DOX concentration. After clinical trial, the remaining dentin was hard and dry. Additionally, mutans streptococci were completely eliminated after 3 months of treatment with RMGIC + 4.5% DOX. The incorporation of DOX provided better antibiofilm effect, without jeopardizing fluoride release and surface microhardness of RMGIC. This combination also improved the in vivo shortterm microbiological effect of RMGIC after partial caries removal.

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

OBJECTIVES: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. MATERIAL AND METHODS: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05). RESULTS: Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment. CONCLUSIONS: The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations.

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

Abstract Objectives: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. Material and Methods: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05). Results: Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment. Conclusions: The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations.

Relationship between the IgA antibody response against Streptococcus mutans GbpB and severity of dental caries in childhood.

OBJECTIVE: Explore the associations between the severity of dental caries in childhood, mutans streptococci (MS) levels and IgA antibody response against Streptococcus mutans GbpB. Moreover, other caries-related etiological factors were also investigated. DESIGN: 36-60 month-old children were grouped into Caries-Free (CF, n=19), Early Childhood Caries (ECC, n=17) and Severe Early Childhood Caries (S-ECC, n=21). Data from socio-economic-cultural status, oral hygiene habits and dietary patterns were obtained from a questionnaire and a food-frequency diary filled out by parents. Saliva was collected from children for microbiological analysis and detection of salivary IgA antibody reactive with S. mutans GbpB in western blot. RESULTS: S-ECC children had reduced family income compared to those with ECC and CF. There was difference between CF and caries groups (ECC and S-ECC) in MS counts. Positive correlations between salivary IgA antibody response against GbpB and MS counts were found when the entire population was evaluated. When children with high MS counts were compared, S-ECC group showed significantly lower IgA antibody levels to GbpB compared to CF group. This finding was not observed for the ECC group. CONCLUSIONS: This study suggests that children with S-ECC have reduced salivary IgA immune responses to S. mutans GbpB, potentially compromising their ability to modify MS infection and its cariogenic potential. Furthermore, a reduced family income and high levels of MS were also associated with S-ECC.