Synthesis and application of triclosan methacrylate monomer in resin composites.

OBJECTIVES: To evaluate the antibacterial activity, bacterial viability, cytotoxicity, and mechanical/physical properties of a novel methacrylate triclosan-derivative monomer (TM) incorporated in dental resin composite. METHODS: TM was synthesized by esterification and, after characterization by FT-IR, was added to an experimental composite. Samples were divided into two groups according to TM presence, i.e., C1 (control) and C2 (C1 + 14.4% TM). Microbiological properties: Specimens (C1 and C2) were prepared and placed on bacterial suspensions of Streptococcus mutans. Antibacterial activity, MTT, and live/dead bacterial viability were used to test the resin composites. All assays were performed in triplicates. Mechanical properties: Specimens underwent compression (CS) and flexural strength (FS) tests conducted in an Instron universal testing machine at a crosshead speed of 0.5 mm/min. Physical properties: Specimens were assessed for Knoop hardness (KHN) and crosslink density (CD). Fourier transform infrared spectroscopy allowed the degree of conversion (DC) to be evaluated. Data were subjected to appropriate statistical tests according to data distribution and assay (p < 0.05). RESULTS: Microbiological properties: C2 showed the lowest biofilm accumulation and the highest membrane-compromised bacteria in the biofilm. Mechanical/physical properties: For CS, FS, KHN, and DC, there was no significant difference between groups C1 and C2; however, significant difference was observed for the CD assay. CONCLUSIONS: The triclosan methacrylate reduces bacterial adhesion of S. mutans and decreased the formation of bacterial biofilm without affecting important polymer properties. The triclosan methacrylate incorporated in resin composite could greatly reduce the live bacterial adhesion of S. mutans and decrease the formation of bacterial biofilm without affecting important polymer properties. CLINICAL SIGNIFICANCE: The resin composites containing triclosan methacrylate could greatly reduce the bacterial adhesion and biofilm formation. That might prevent the secondary caries round the margins of the restorations.

A novel Triclosan Methacrylate-based composite reduces the virulence of Streptococcus mutans biofilm.

The use of antimicrobial monomers, linked to the polymer chain of resin composites, is an interesting approach to circumvent the effects of bacteria on the dental and material surfaces. In addition, it can likely reduce the incidence of recurrent caries lesions. The aim of this study was to evaluate the effects of a novel Triclosan Methacrylate (TM) monomer, which was developed and incorporated into an experimental resin composite, on Streptococcus mutans (S. mutans) biofilms, focusing on the analyses of vicR, gtfD, gtfC, covR, and gbpB gene expression, cell viability and biofilm characteristics. The contact time between TM-composite and S. mutans down-regulated the gbpB and covR and up-regulated the gtfC gene expression, reduced cell viability and significantly decreased parameters of the structure and characteristics of S. mutans biofilm virulence. The presence of Triclosan Methacrylate monomer causes harmful effects at molecular and cellular levels in S. mutans, implying a reduction in the virulence of those microorganisms.

Antimicrobial Activity of Two Root Canal Filling Pastes in Deciduous Teeth: an In Vitro Study / Avaliação "in vitro" da Atividade Antimicrobiana de Duas Pastas Obturadoras de Canais Radiculares de Dentes Decíduos

O tratamento endodôntico de dentes decíduos é de suma importância para que se possa preservar a dentição primária e, assim, promoverdesenvolvimento craniofacial adequado, oclusão normal e qualidades estéticas. No entanto, para que isso ocorra, é necessário o uso de pastasobturadoras com propriedades biológicas importantes para a preservação do dente. O objetivo deste estudo foi avaliar in vitro a atividadeantimicrobiana de duas pastas obturadoras utilizadas em dentes decíduos, Vitapex® e Calcipex®, em espécies microbianas comumenteencontradas em infecções endodônticas (Candida albicans, Enterococcus faecalis, Streptococcus mutans, Streptococcus sanguinis, Escherichiacoli e Staphylococcus aureus), utilizando o teste de difusão em ágar. Foram utilizadas placas de BHI (Brain Heart Infusion) e confeccionadosquatro pontos equidistantes, imediatamente preenchidos com o Vitapex® cimentos e Calcipex®. O gluconato de clorexidina a 1% (CHX) e águadestilada foram utilizados como controle positivo e negativo, respectivamente. Após a incubação das placas a 37 °C durante 24 h, o diâmetrodas zonas de inibição do crescimento bacteriano ao redor dos poços foi medido (em milímetros) com um compasso de calibre digital com luzrefletida. Este teste foi realizado em triplicata e os dados foram submetidos à análise de variância e teste de Tukey (? = 0,05). Ambas as pastastiveram atividade antimicrobiana, mas Calcipex® foi mais eficiente para a maioria das cepas. O halo formado nos experimentos contendoas cepas de S. mutans e S. sanguinis foi semelhante para ambas as pastas. No presente estudo, podemos sugerir que Calcipex® apresentou amelhor propriedade antimicrobiana em relação aos microrganismos estudados.

Effects of chemical agents on physical properties and structure of primary pulp chamber dentin.

This study evaluated the effects of chemical agents on the physical properties and structure of primary pulp chamber dentin using surface roughness, microhardness tests, and scanning electron microscopy (SEM). Twenty-five primary teeth were sectioned exposing the pulp chamber and were divided into five groups (n = 5): NT, no treatment; SH1, 1% sodium hypochlorite (NaOCl); SH1U, 1% NaOCl + Endo-PTC®; SH1E, 1% NaOCl + 17% EDTA; and E, 17% EDTA. After dentin treatment, the specimens were submitted to roughness, microhardness testing, and SEM analysis. Roughness and microhardness data were submitted to one-way ANOVA and Tukey's test (P < 0.05). The SH1E group showed the highest roughness, followed by the E group (P < 0.05) when compared with the NT, SH1, and SH1U groups. Microhardness values of SH1 and SH1U showed no significant difference as compared to the NT (control) group (P > 0.05). Microhardness values could not be obtained in the EDTA groups (SH1E and E). The presence of intertubular dentin with opened dentin tubules was observed in the NT, SH1, and SH1U groups. SH1E showed eroded and disorganized dentin with few opened tubules and the intertubular/peritubular dentin was partially removed. Considering the physical and structural approaches and the chemical agents studied, it can be concluded that NaOCl and NaOCl associated with Endo-PTC® were the agents that promoted the smallest changes in surface roughness, microhardness, and structure of the pulp chamber dentin of primary teeth.

In vitro and in vivo investigation of the biological and mechanical behaviour of resin-modified glass-ionomer cement containing chlorhexidine.

OBJECTIVES: To evaluate: (1) the in vitro antibacterial, cytotoxic and mechanical properties of a resin-modified glass ionomer cement (RMGIC) containing different concentrations of chlorhexidine (CHX) and (2) the in vivo microbiologic action of the best concentration of CHX associated with the RMGIC applied on remaining dentine after indirect pulp treatment (IPT). METHODS: For the in vitro studies, RMGIC was associated with 0.2, 0.5, 1.25 and 2.5% CHX. Microbiologic evaluation consisted of an agar diffusion test on cariogenic bacteria for 24h. Odontoblast-like cell metabolism and morphology analyses measured the cytotoxic effects of the RMGIC groups after 24h. The same groups were submitted to compressive and diametral tensile strength. The in vivo treatment consisted of IPT using an RMGIC associated with the best CHX concentration. Clinical and microbiologic evaluations were performed before and after 3 months. RESULTS: The use of 1.25% CHX significantly improved the antibacterial effects of the evaluated RMGIC, without causing any detrimental effects to the odontoblast-like cells and on the mechanical properties. This RMGIC and CHX combination completely eliminated mutans streptococci after 3 months of IPT. CONCLUSION: The RMGIC and 1.25% CHX mixture showed great biological and mechanical behaviour and could be a good treatment against caries progression. CLINICAL SIGNIFICANCE: The association of CHX with a liner RMGIC opens a new perspective for arresting residual caries after IPT.

Biomechanical degradation of the nano-filled resin-modified glass-ionomer surface.

PURPOSE: To evaluate in the laboratory the roughness (Ra) and micromorphology surface of the nanofilled resin-modified glass-ionomer (Ketac N100) subjected to biomechanical degradation, compared to Vitremer, Ketac Molar Easymix and Fuji IX. METHODS: Specimens obtained from the ionomers were divided into two storage groups (n = 10): relative humidity and S. mutans biofilm (biodegradation). After 7 days, Ra values and micrographs were obtained. Then, the brushing abrasion test (mechanical degradation) was conducted with dentifrice slurry (three-body) and the specimens were reassessed. Data were submitted to repeated measures three-way ANOVA and Tukey tests (P < 0.05). RESULTS: There was significant interaction among the factors: material, storage and abrasion (before/after). Vitremer showed similar Ra values between storage groups, while the other materials presented higher Ra values after biodegradation test. Concerning biomechanical challenge, Ketac N100 presented the lowest Ra values. Ketac Molar Easymix and Fuji IX presented undesirable roughening of their surfaces under the detrimental conditions tested. The eroded aspect after biodegradation with filler exposure after mechanical degradation was evident.

Marginal adaptation of indirect restorations using different resin coating protocols.

This study evaluated the influence of material combinations used in the resin coating technique (RCT) on the marginal adaptation of indirect restorations with gingival margins in enamel (EM) and cement (CM). Eighty third-molars were used. Two cavities were prepared in each tooth. The cavities were distributed into 16 groups. Cavities with EM were filled with the following material combinations: G1: Single-Bond 2 (Sb2), G2: Sb2 + Bond/Scotchbond-Multipurpose (Sb2B), G3: Sb2 + Filtek-Flow Z350 (Sb2Fl), G4: Scotchbond-Multipurpose (SBMP), G5: Clearfil-S3 (CS3), G6: CS3 + Bond/Clearfil-SE Bond (CSE3B), G7: CS3 + Protect Liner F (CS3PL) and G8: Clearfil SE Bond + Protect Liner F (CSEBPL). The same combinations were applied to the cavities in CM: G9, G10, G11, G12, G13, G14, G15, G16, respectively. The fillings were performed with the Sinfony-System (3M/ESPE). After 24 h, the teeth were submitted to thermocycling (2,000 cycles, 5° to 55°C) and load-cycling (50,000 cycles, 50 N). Next, the Caries-Detector (Kuraray) was applied to the restoration margins. Images from the proximal margin were evaluated using the Image-Tool 3.0 software. The results were submitted to ANOVA and Tukey's test (α=0.05). The mean values (%) for the groups were: EM: G1=46.68, G2=15.53, G3=19.83, G4=27.53; G5=59.49, G6=25.13, G7=34.37, G8=15.20; CM: G9=38.38, G10=23.25, G11=26.97, G12=25.85, G13=37.81, G14=30.62, G15=29.17, G16=20.31. The highest percentages of marginal gap on EM or CM were found in the groups that did not use a liner. It can be concluded that the most appropriate RCT combinations were the groups that used a liner.

In situ and in vitro comparison of laser fluorescence with visual inspection in detecting occlusal caries lesions.

The aim of this study was to compare the in situ and in vitro performances of a laser fluorescence (LF) device (DIAGNOdent 2095) with visual inspection for the detection of occlusal caries in permanent teeth. Sixty-four sites were selected, and visual inspection and LF assessments were carried out, in vitro, three times by two independent examiners, with a 1-week interval between evaluations. Afterwards, the occlusal surfaces were mounted on the palatal portion of removable acrylic orthodontic appliances and placed in six volunteers. Assessments were repeated and validated by histological analysis of the tooth sections under a stereomicroscope. For both examiners, the highest intra-examiner values were observed for the visual inspection when in vitro and in situ evaluations were compared. The inter-examiner reproducibility varied from 0.61 to 0.64, except for the in vitro assessment using LF, which presented a lower value (0.43). The methods showed high specificity at the D(1) threshold (considering enamel and dentin caries as disease). In vitro evaluations showed the highest values of sensitivity for both methods when compared to the in situ evaluations at D(1) and D(2) (considering only dentinal caries as the disease) thresholds. For both methods, the results of sensitivity (at D(1) and D(2)) and accuracy (at D(1)) showed significant differences between in vitro and in situ conditions. However, the sensitivity (at D(1) and D(2)), specificity and accuracy (both at D(1)) of the methods were not significantly different when the same condition was considered. It can be concluded that visual inspection and LF showed better performance in vitro than in situ.

Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement.

This study evaluated the Knoop hardness and polymerization depth of a dual-cured resin cement, light-activated at different distances through different thicknesses of composite resin. One bovine incisor was embedded in resin and its buccal surface was flattened. Dentin was covered with PVC film where a mold (0.8-mm-thick and 5 mm diameter) was filled with cement and covered with another PVC film. Light curing (40 s) was carried out through resin discs (2, 3, 4 or 5 mm) with a halogen light positioned 0, 1, 2 or 3 mm from the resin surface. After storage, specimens were sectioned for hardness measurements (top, center, and bottom). Data were subjected to split-plot ANOVA and Tukey's test (alpha=0.05). The increase in resin disc thickness decreased cement hardness. The increase in the distance of the light-curing tip decreased hardness at the top region. Specimens showed the lowest hardness values at the bottom, and the highest at the center. Resin cement hardness was influenced by the thickness of the indirect restoration and by the distance between the light-curing unit tip and the resin cement surface.

Effect of light energy density on conversion degree and hardness of dual-cured resin cement.

This study evaluated the effect of different light energy densities on conversion degree (CD) and Knoop hardness number (KHN) of RelyX ARC (RLX) resin cement. After manipulation according to the manufacturer's instructions, RLX was inserted into a rubber mold (0.8 mm x 5 mm) and covered with a Mylar strip. The tip of the light-curing unit (LCU) was positioned in contact with the Mylar surface. Quartz-tungsten-halogen (QTH) and light-emitting diode (LED) LCUs with light densities of 10, 20 and 30 J/cm2 were used to light-cure the specimens. After light curing, the specimens were stored dry in lightproof containers at 37 degrees C. After 24 hours, the CD was analyzed by FT-Raman and, after an additional 24-hours, samples were submitted to Knoop hardness testing. The data of the CD (%) and KHN were submitted to two-way ANOVA and the Tukey's test (alpha = 0.05). QTH and LED were effective light curing units. For QTH, there were no differences among the light energy densities for CD or KHN. For LED, there was a significant reduction in CD with the light energy density set at 10 J/cm2. KHN was not influenced by the light-curing unit and by its light energy density.

In vivo evaluation of laser fluorescence performance using different cut-off limits for occlusal caries detection.

The aim of this in vivo study was to evaluate the performance of laser fluorescence (LF) comparing different cut-off limits for occlusal caries detection. One hundred and thirty first permanent molars were selected. Visual examination and LF assessments were performed independently. The extent of caries was assessed after operative intervention. New cut-off limits were established and compared with those proposed by the manufacturer and by Lussi et al. (Eur J Oral Sci 109:14-19, 2001). Similar sensitivity and higher specificity was found at D(2) (considering as disease only dentin caries) when the LF cut-off limits proposed by Lussi et al. and the new one were compared. At the D(3) threshold (considering as disease only deep dentin caries), no statistically significant difference among the cut-off limits for sensitivity was found. However, the new cut-off limits showed higher specificity. The LF device provided good ability to detect dentin caries lesions. Furthermore, the new cut-off limits and the values proposed by Lussi et al. could be suggested for the in vivo detection of occlusal caries.

Effect of restorative technique and thermal/mechanical treatment on marginal adaptation and compressive strength of esthetic restorations.

This study evaluated the compressive strength and marginal adaptation of composite onlays using indirect and direct techniques after thermal and mechanical cycling. Onlay standardized cavities were prepared in 50 permanent molars and restored with Z-250 resin composite using indirect (IRT) or direct (DRT) restorative techniques. The restorations were either submitted or not submitted to thermal (500 cycles, 5 degrees to 55 degrees C) and mechanical cycling (50,000 cycles, 50N). The teeth were distributed to five groups (n=10): G1-IRT/cycling; G2-IRT/no cycling; G3-DRT/cycling; G4-DRT/no cycling and G5 (control group)-sound teeth. All prepared teeth were stored in 100% relative humidity at 37 degrees C for 24 hours, followed by finishing with Sof-Lex discs. A caries detector solution was applied on the tooth-restoration interface of all teeth for five seconds, followed by washing and drying. Four digital photographs were taken of each tooth surface. The extent of gaps was measured using standard software (Image Tool 3.0). All groups were submitted to compression testing in a universal testing machine (INSTRON) at a crosshead speed of 1 mm/minute until failure. The compressive strength (CS) and marginal adaptation data were submitted to ANOVA and Tukey test (p<0.05). For both evaluation criteria (compressive strength and marginal adaptation), there were no statistically significant differences among the restorative techniques. Deterioration over time was observed for both types of restorations. However, the prevalence of catastrophic fractures increased among direct restorations. The application of thermal/mechanical cycling only influenced marginal adaptation.

Clinical manifestations and oral findings in Fraser syndrome.

This article is the first known case report of Fraser syndrome in the dental literature. Its purpose was to present the clinical manifestations, oral findings, and dental treatment of a 14-year, 10-month-old female patient. Fraser syndrome is a rare recessive autosomal genetic disorder characterized by multisystemic malformation, usually comprising cryptophthalmos, syndactyly, and renal defects. The child presented with: (1) hydrocephaly; (2) face asymmetry; (3) low-inserted ears; (4) flat nose bridge; (5) cryptophthalmos; (6) bilateral absence of eyeballs; (7) hypertelorism; (8) syndactyly on the left fingers and toes; (9) skeletal defects; and (10) lower limb asymmetry. The intraoral examination revealed: (1) complete primary denture; (2) malocclusion; (3) tooth crowding; (4) ogival palate; (5) normal labial frena; (6) absence of lingual frenum (not compromising the tongue movements); (7) parched lips; (8) supragingival calculus adhered to all tooth surfaces; and (9) moderate gingivitis. The dental treatment consisted of periodic monitoring of the patient's oral health status and supragingival scaling associated with topical applications of 0.12% chlorhexidine digluconate gel at 2-week intervals to reduce gingivitis.