Antibacterial Effect of Surface Pretreatment Techniques against Streptococcus Mutans.

OBJECTIVE: The aim of this study was to evaluate the antibacterial surface pretreatment methods against Streptococcus mutans within the infected dentin surface using a tooth cavity model. MATERIAL AND METHODS: Seventy-two cavities were prepared on caries-free third molars (n = 8). After sterilization, teeth were inoculated with S. mutans for 48 h. One cavity of each tooth was used to evaluate the infection. Following inoculation, infected cavity surfaces were treated either with (1) Er:YAG Laser (1W; 5x5s, Smart 2940D Plus, Deka Laser), (2) Ozone (80s; HealOzone, Kavo), (3) ErYAG-Ozone combination, (4) Er:YAG-Ozone-CHX combination, (5) Chlorhexidine (CHX), (6) Clearfil Protect Bond (PB), (7) potassium-titanyl-phosphate (KTP) Laser (1W; 60 s, SMARTLITE D, Deka Laser), (8) KTP-Ozone combination, and (9) KTP-Ozone-CHX. Standardized amounts of dentin chips were obtained from the cavity walls, and the number of bacteria recovered was counted. Kruskal-Wallis test was used for statistical analyzes. RESULTS: Both sole antibacterial materials, CHX or Protect Bond application, exhibited the most effective antibacterial activity with 125 and 156 CFU is an acronym of "colony forming unit" usullay mentioned by acronym. (CFU/ml), respectively, among the groups evaluated (P < 0.05). Er:YAG laser irradiation and its combinations with other antibacterial surface pretreatment applications also inhibited the bacterial growth with, respectively, 1444, 406, and 294 CFU/ml bacterial recovery being more efficient than KTP laser irradiation and ozone combinations. CONCLUSIONS: As an alternative device with photodynamic effects, Er:YAG and KTP laser irradiations and their further combinations during the cavity pretreatment procedure with chlorhexidine and ozone treatments exerted antibacterial effect against S. mutans, whereas chlorhexidine and antibacterial dentin bonding application solely have the highest antibacterial effects.

Sodium Thiosulfate for Recovery of Bond Strength to Dentin Treated with Sodium Hypochlorite.

INTRODUCTION: The aim of this study was to evaluate the efficacy of sodium thiosulfate (Na2S2O3) for restoring adhesion to pulp chamber dentin treated with sodium hypochlorite (NaOCl) and EDTA. METHODS: Sixty-three crowns of bovine incisors were cut to expose the dentin pulp chamber. The specimens were polished and randomly distributed into 9 groups (n = 7) according to the following protocols used: 0.9% sodium chloride for 30 minutes (negative control), 5.25% NaOCl for 30 minutes, 17% EDTA for 3 minutes, and 5.25% NaOCl for 1 minute (positive control). The other groups, after treatments with NaOCl and EDTA, were immersed in 0.5% or 5% Na2S2O3 for 1, 5, and 10 minutes or just immersed in an inert solution for 10 minutes (0.9% sodium chloride). After drying the specimens, Scotchbond Multi-Purpose (3M ESPE, St Paul, MN) was applied to the pulp chamber dentin followed by Filtek Z250 composite (3M ESPE). Six rectangular slabs were obtained from each specimen, and the dentin/resin interface was tested by using a universal testing machine. The resulting data were submitted to 1-way analysis of variance and the Duncan test (P = .05). RESULTS: There was a significant decrease in bond strength regarding NaOCl and EDTA (P < .05). When 5% Na2S2O3 was used for 10 minutes, the bond strength was found to be statistically equal to the negative control and higher than the positive control (P < .05). CONCLUSIONS: The use of Na2S2O3 can significantly increase the bond strength of composite resin to NaOCl/EDTA-treated dentin, allowing adhesive restorations to be immediately applied after endodontic treatment.

Comparison of different dentin pretreatment protocols on the bond strength of glass fiber post using self-etching adhesive.

INTRODUCTION: This study compared the influence of different irrigants with and without ultrasound or laser irradiation on the bond strength of glass fiber posts using a self-etching adhesive in a supplementary dentin pretreatment. METHODS: Ninety bovine incisor roots were divided into 3 groups according to the irrigant tested: 2% chlorhexidine (CHX) (n = 30); 2.5% sodium hypochlorite (NaOCl) (n = 30), and saline solution (control) (n = 30). Each group was randomly divided into 3 subgroups according to the supplementary dentin pretreatment: ultrasound, Nd:YAG laser, and nonsupplemented (control). A self-etching adhesive system (Futurabond DC; VOCO GmbH, Cuxhaven, Germany) was used, and the glass fiber posts were cemented with dual-cure epoxy-based luting agent (Bifix QM, VOCO GmbH). All roots were sectioned transversely, and the push-out test was performed. Failure mode analysis was also evaluated. RESULTS: Bond strength decreased significantly after the use of 2.5% NaOCl in all root thirds (P < .05). CHX showed no difference in the mean bond strength value compared with saline solution (P > .05). The supplementary dentin pretreatment using the Nd:YAG laser or ultrasound did not improve the bond strength values for both NaOCl and CHX (P > .05). Moreover, the apical third exhibited the lowest mean bond strength values (P < .05). Analysis indicated that the predominant failure mode was the mixed type. CONCLUSIONS: Regardless of the irrigant used, the supplementary dentin pretreatment with ultrasound or laser irradiation showed no improvement in bond strength. Also, the use of NaOCl decreased the bond strength of glass fiber posts using a self-etching adhesive system, whereas CHX preserved it.

In vitro study of the antibacterial properties and microbial colonization susceptibility of four self-etching adhesives used in orthodontics.

OBJECTIVES: 1. To determine the in vitro antibacterial effectiveness of the orthodontic bonding Transbond XT (3M Unitek) and four self-etching adhesives with possible use in orthodontic bonding (Clearfil Protect Bond, CPB; Clearfil Self-etching Bond, CSB; Transbond Plus Self-Etching Primer, TSEP; iBond) against Streptococcus mutans and Lactobacillus gasseri in order to compare that capacity among the adhesives and with respect to Transbond XT; 2. To determine the bacterial adhesion capacity of the above mentioned microorganisms to the tested adhesives. MATERIALS AND METHODS: The inhibitory effects of the adhesives against S. mutans and L. gasseri were examined using the agar diffusion method with Whatman No.1 5mm disks loaded with 15 µl of adhesive, UV polymerized, layered on previously inoculated BHI and MRS plates incubated microaerobically for 48 hours at 37 degree C. Data were analysed with Kruskal-Wallis (P < 0.05) and Mann-Whitney tests, applying the Bonferroni correction (P < 0.003). Bacterial adhesion was studied with scanning electron microscopy. RESULTS: Only CPB and iBond produced a clear growth inhibition halo against S. mutans and L. gasseri (P < 0.0001). iBond was the only tested product to which the bacteria adhere profusely, particularly S. mutans. CONCLUSIONS: CPB has shown antimicrobial properties in vitro, and, provided the limitations of an in vitro study, the use of this self-etching adhesive may contribute to reduce microbial decalcification, making the use of this self-etching adhesive an attractive option for bracket bonding.

Bond strengths of one-step self-etch adhesives to laser-irradiated and bur-cut dentin after water storage and thermocycling.

OBJECTIVE: The objectives of this study were to evaluate the microtensile bond strength (µTBS) of one-step self-etch adhesive systems to Er:YAG laser-irradiated and bur-cut dentin after water storage and thermocycling. BACKGROUND DATA: The Er:YAG laser is a promising alternative method for cavity preparation; however, no study has compared the effect of laser irradiation and aging procedures on the adhesion of one-step self-etch adhesives to dentin. METHODS: Seventy-two third molars were selected and randomly divided according to cavity preparation method (Er:YAG laser and bur-cut). One-step self-etch adhesive systems (Clearfil S(3) Bond, AdheSE One and Adper Easy One) were used to bond the composite to dentin. Following the adhesive procedure, the specimens were subdivided according to aging conditions (24 h in water control [C], 6 months of water storage [WS] and 10.000 thermocycles [TC]). The µTBS was determined in a universal testing machine. Three-way ANOVA, independent samples t test, and post-hoc comparisons test (α=0.05) were performed on all data. RESULTS: There was no statistical difference in µTBS between Er:YAG laser-irradiated and bur-cut dentin (p>0.05). Similarly, no significant difference was found in µTBS between C, WS, and TC specimens (p>0.05). Moreover, Clearfil S(3) Bond presented the highest µTBS to dentin in both laser-irradiated and bur-cut cavity preparation methods. CONCLUSIONS: Neither bur-cut nor Er:YAG laser-irradiated dentin was affected by the aging methods used to simulate degradation of the adhesive interface. Er:YAG laser treatment may be used as an alternative cavity preparation method.

Mechanical and micromorphological evaluation of chlorhexidine-mediated dentin remineralization.

Chlorhexidine (CHX) has been reported to reduce self-degradation of collagen fibrils by inhibiting host-derived protease activity in demineralized dentin. Theoretically, if the collagen fibril scaffold of demineralized dentin maintains its original crosslinkage pattern on treatment with CHX and appropriate supplementation with necessary mineral sources, dentin remineralization may occur in demineralized lesions. In this study, we provide direct mechanical and micromorphological evidence for the ability of CHX to promote remineralization of demineralized dentin. Specifically, with respect to demineralized dentin blocks treated with different concentrations of CHX (0.02-2%) and stored in simulated body fluid, we have observed a significant increase in the elastic modulus of dentin treated with relatively high concentrations of CHX (0.2 and 2%) as storage time increased, whereas the elastic modulus of the non-CHX treated control group decreased. We have also observed a dense mineral deposition along collagen fibrils in the dentin group treated with 0.2 and 2% CHX via field emission scanning electron microscopy.

Effect of silane coupling agents and alloy primers on adhesion to titanium.

AIM: Titanium-ceramic adhesion is known to be not ideal yielding to ceramic fractures especially in extensive implant reconstructions. Intraoral repair actions could be performed chairside using adhesion promoters. This study evaluated the adhesion of resin composite to titanium alloy using different silane coupling agents and alloy primers in combination with surface conditioning methods after aging. METHODS: Titanium alloy disks were embedded in PMMA and wet polished to 1200 grit silicon carbide abrasive. Silanes and alloy primers used in combination with surface conditioning methods were as follows: 1) Al2O3 (50 µm) and Alloy Primer (Kuraray); 2) Al2O3 (50 µm) and V-Primer (Sun Medical); 3) SiO2 (30 µm) and Silane (ESPE-Sil) (CoJet System, 3M ESPE); 4) Al2O3 (50 µm) and Silane (ESPE-Sil); 5) Al2O3 (50 µm) and Cesead II Opaque Primer (Kuraray); 6) Al2O3 (50 µm) and Alloy Primer and Clearfil SE Bond Primer and Clearfil Porcelain Bond Activator (Clearfil Repair System, Kuraray). A thin layer of Sinfony opaquer was then applied, polymerized and a direct resin composite (Quadrant Photoposterior, Cavex) was adhered onto the conditioned titranium surfaces using polyethylene molds. After thermocycling (6000 cycles at 5-55 °C), specimens were submitted to shear loading in the Universal Testing Machine (crosshead speed: 1 mm/min). Failure types were classified as adhesive, cohesive in resin and a combination of adhesive and cohesive failures (mixed) after debonding. The data (MPa) were analyzed statistically using One-way ANOVA and Tukey's tests. RESULTS: Significant difference was observed between the groups (P<0.05) (1-way ANOVA). Significantly higher results were obtained from Groups 1 (25.4±7) and 6 (26.3±5) than those of other groups (11.4±3 - 22.6±9) (P<0.05) (Tukeys' test). Group 2 presented the lowest mean bond strength among all groups (11.4±3) (P<0.05). While Group 1 showed mainly cohesive (4 out of 10) and mixed failures (6 out of 10) and no adhesive failures, other groups presented mainly adhesive and mixed failures. CONCLUSION: Conditioning titanium surfaces with 50 µm Al2O3 followed by Alloy Primer or silane mixture of Clearfil Repair system delivered the most stable repair bond strength of the resin composite to titanium compared to other alloy primers and silanes tested.

The effects of hyaluronic acid, calcium hydroxide, and dentin adhesive on rat odontoblasts and fibroblasts.

The aim of this study was to investigate the effects and efficiency of pulp capping preparations based on hyaluronic acid, calcium hydroxide, and dentin adhesive on the pulp tissue of Sprague-Dawley rats. The rats were killed and extracted teeth sectioned transversely through the pulp. The slices were placed in a RPMI 1640 cell culture medium supplemented with 10 % foetal calf serum. During 14 days of cultivation cultures were treated with preparations that contained hyaluronic acid (Gengigel Prof®), and calcium hydroxide (ApexCal®), or with dentin adhesive (Excite®). Cellularity and viability of fibroblasts and odontoblasts was analysed using a haemocytometer. Hyaluronic acid proved most efficient and the least toxic for direct pulp capping. Even though calcium hydroxide and dentin adhesive demonstrated a higher degree of cytotoxicity, their effects were still acceptable in terms of biocompatibility.

Novel methodology to evaluate the effect of residual moisture on epoxy resin sealer/dentine interface: a pilot study.

AIM: To evaluate the sealer/dentine interface associated with an epoxy resin sealer using the combination of Goldner's trichrome stain (GTS) and scanning electron microscopy (SEM) to verify the use of the experimental methodology. METHODOLOGY: Extracted human maxillary incisors (6) were subjected to root canal treatment. Subsequent to pulp removal, canal instrumentation and smear layer removal using EDTA and NaOCl, teeth were randomly and equally assigned to a 'wet' or 'dry' group. The 'dry' group was desiccated (95% ethanol/suction/paper points/air-drying), whilst the 'wet' group was treated with a saline rinse/suction/single paper point. Canals were then filled with an epoxy-based resin sealer and warm vertical gutta-percha compaction. After 7-day storage at 37°C, roots from each group were sectioned into apical, middle and coronal horizontal subsections that were cut and split into paired halves and evaluated with GTS or SEM. With GTS sections, hybrid layer and sealer tubular penetration were measured (n=15 measurements/intracanal location/condition) and evaluated using a two-factor repeated measures analysis of variance. The SEM qualitative analysis of paired sections was included as a complementary confirmation of GTS analyses. RESULTS: In dry and wet groups, there was no conspicuous sealer/dentine interface hybrid layer, irrespective of canal location. However, dry specimens exhibited more uniform sealer distribution with deeper tubular penetration in the coronal and middle third (P<0.05). In contrast, there was decreased sealer distribution and tubule penetration in the apical third, regardless of moisture condition (P<0.05). CONCLUSIONS: The experimental methodology (combination of GTS and SEM) can be used to evaluate the intracanal resin sealer/dentine interface. The pilot data indicated that thorough drying of the root canal system may result in improved epoxy resin sealer distribution and deeper resin sealer tubular penetration, especially in the coronal and middle thirds of root canals.

An SEM evaluation of conditioned and bonded enamel following carbamide peroxide bleaching and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) treatment.

OBJECTIVES: The study aimed to evaluate, (a) the surface morphology of acid etched/conditioned enamel following carbamide peroxide bleaching with/without casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (Tooth Mousse (MI Paste); GC Corp., Tokyo, Japan) treatment; and b) the nature of the bonded resin-enamel interfaces formed with a self-etching primer adhesive. METHODS: Twenty-four human adult molars were each sectioned into four, the specimens divided and treated according to four experimental groups: 1, no treatment; 2, 16% carbamide peroxide bleaching; 3, CPP-ACP paste; 4, bleaching and CPP-ACP paste. A self-etching primer adhesive (Clearfil SE Bond, CSE) was used. The specimens were further divided into four subgroups for etching/conditioning: A, CSE Primer only; B, 30-40% phosphoric acid and CSE primer; C, 15% EDTA and CSE primer; D, 20% polyacrylic acid and CSE primer. Bonded specimens were also prepared. The morphology of the etched/conditioned enamel surfaces and polished resin-enamel interfaces of the bonded specimens were observed by field-emission scanning electron microscopy (FE-SEM). RESULTS: Treatment with CPP-ACP did not inhibit phosphoric acid etching of enamel. Poorly defined enamel etch patterns were observed with the other conditioners in all the groups. The morphology of the bonded resin-enamel interfaces observed on FE-SEM for each acid etching/conditioning subgroup was similar in all the experimental groups, except after bleaching. Resin infiltration into enamel was observed with prior phosphoric acid etching and polyacrylic acid conditioning and was unaffected by experimental group treatments. CONCLUSIONS: The use of a CPP-ACP paste with or without prior bleaching did not inhibit enamel etching. Enamel etching/conditioning may help improve bonding efficiency of the self-etching primer adhesive after CPP-ACP treatment.

Micro-tensile bond strength to bovine sclerotic dentine: influence of surface treatment.

OBJECTIVE: The objective of this study was to evaluate the influence of the surface treatment and acid conditioning (AC) time of bovine sclerotic dentine on the micro-tensile bond strength (micro-TBS) to an etch and rinse adhesive system. MATERIALS AND METHOD: Thirty-six bovine incisors were divided into six groups (n=6): G1 sound dentine submitted to AC for 15s; G2-G6 sclerotic dentine: G2-AC for 15s; G3-AC for 30s; G4-EDTA and AC for 15s; G5-diamond bur and AC for 15s; G6-diamond paste and AC for 15s. An adhesive system was applied to the treated dentine surfaces followed by a hybrid composite inserted in increments and light cured. After 24h storage in water at 37 degrees C, the specimens were perpendicularly cut with a low-speed diamond saw to obtain beams (0.8 mm x 0.8 mm cross-sectional dimensions) for micro-TBS testing. Data was compared by ANOVA followed by Tukey's test (p

Evaluation of the enamel etching capacity of six contemporary self-etching adhesives.

OBJECTIVES: The purpose of this study was to evaluate the capacity of six contemporary self-etch primers/adhesives to demineralize ground enamel by means of ultrastructural analysis of the etching surface under SEM and by spectroscopic measurement of the percentage of calcium and phosphate ions dissolved. METHODS: Seventy non-carious extracted human third molars were sub-divided into 2 groups of 35 teeth each. The teeth of the first group were ground to expose flat, polished enamel surfaces 3-4mm thick. The samples thus obtained were treated with six self-etch bonding systems and a phosphoric acid gel (control group). The self-etch priming agent was then eliminated and the etched enamel surface observed by SEM. From the teeth of the second group, disc-shaped specimens were made from ground enamel and subjected to application of each of the six self-etchants. Once the etching product had been rinsed off, the rinse solution was analyzed by atomic flame spectroscopy to evaluate the percentage of calcium and phosphate ions dissolved. RESULTS: SEM images show that AdheSE, Adper Prompt L-Pop and Xeno III, despite having a less intensive etching efficacy than phosphoric acid, gave a regular pattern over a considerable surface area and depth. iBond and One-Up Bond F gave less regular demineralization. For Clearfil SE Bond, the demineralization was ineffective. Results of the percentage of mineral loss show that Adper Prompt L-Pop and Xeno III were the most efficient self-etch products. AdheSE, iBond and One-Up Bond F, respectively exhibited decreasing demineralizing capacity. Clearfil SE Bond, however, gave low proportions of calcium and phosphate ions loss and was considered unsatisfactory. CONCLUSION: The action on enamel was not the same for all self-etch systems tested. The etching potential of the self-etch adhesives was lower than that of phosphoric acid but some self-etch systems, particularly those with monomers containing phosphate derivatives, gave results close to those obtained with phosphoric acid.

Antibacterial activities of MDPB and fluoride in dentin bonding agents.

The aim of this study was to compare in vitro antibacterial activity of MDPB containing bonding system ABF with activities of three Fluoride containing bonding systems (Fuji Bond LC (FBLC), Prime&Bond NT (PBNT), and FluoroBond (FLB). Two bacterial strains were tested: Streptococcus mutans and Lactobacillus acidophilus. The study was performed on Muller Hinton Agar by Agar Well Technique. The bacterial agar was evenly distributed over the surface of petri dishes. Standard wells were punched into the agar. The test materials were placed in the wells of Muller Hinton agar plates, inoculated with Streptococcus mutans NCTC10449 and Lactobacillus acidophilus. The diameters of inhibition zones produced around the materials were measured after 24 h of incubation at 37 +/- 1 degrees C. For statistical analysis, Duncan's multiple range test was used. The primers of bonding agents were highly effective against to Streptococcus mutans. The MDPB containing primer of ABF Bond produced the greatest inhibition zones against to Lactobacillus acidophilus. It was followed by FLB primer. Lactobacillus acidophilus was resistant to FBLC primer and bonding, ABF, PBNT and FLB bonding agents. The results of this study indicated that, incorporation of MDPB in primer of self-etch system increased its antibacterial activity especially against to Lactobacillus acidophilus. However, all bonding systems except for bonding agent of ABF showed some antibacterial activity against to Streptococcus mutans.

Incompatibility of oxalate desensitizers with acidic, fluoride-containing total-etch adhesives.

The use of oxalate desensitizers on acid-etched dentin prior to adhesive application can result in subsurface tubular occlusion by calcium oxalate crystals. However, the solubility of calcium oxalate increases in acidic solution. We hypothesized that total-etch adhesives can, depending upon their pH, interact with oxalate-desensitizer-treated dentin in an adverse manner. Acid-etched human dentin treated with 2 oxalate desensitizers (BisBlock and Super Seal) was bonded with 4 simplified total-etch adhesives: One-Step (OS), Single Bond (SB), OptiBond Solo Plus (OB), and Prime&Bond NT (PB). Composite-dentin beams were examined by SEM and TEM, both of which revealed numerous spherical globules on OB- and PB-bonded, desensitizer-treated dentin, but not in OS or SB samples. Bond strengths produced by OB and PB were significantly lower in oxalate-treated specimens than those produced by OS or SB. These surface globules may have interfered with hybridization of demineralized dentin with OB and PB resins and caused compromised bond strengths.

Effect of sodium hypochlorite treatment on the molecular composition and morphology of human coronal dentin.

PURPOSE: The aim of the present study was to evaluate the deproteination potential of 5% aqueous NaOCl solution applied by rubbing action on the molecular composition and morphology of smear-layer covered and acid-etched human coronal dentin surfaces. MATERIALS AND METHODS: Paired specimens (n = 4 x 2 per group) of acid-etched (Group A) and smear-layer covered (Group B) human coronal dentin surfaces were sequentially treated with the NaOCl solution for time intervals ranging from 5 s to 120 s and analyzed by reflectance FTIR microspectroscopy and tapping mode atomic force microscopy. The changes in the mineral (v4 P-O stretching vibrations) to matrix (C = O stretching vibrations of amide I) peak area ratios and in the Ra roughness parameter were used to quantify the effect of treatment. Two-way ANOVA and Dunn's tests were used to assess the differences within each group and between groups (a = 0.05). RESULTS: In both groups, NaOCl treatment reduced organic matrix (amide I, II, III peaks), but did not affect carbonates and phosphates. In group A, the rate of deproteination was slow, and reached a peak value after 120 s. Tubule orifices became visible after 40 s of treatment; after 120 s, excessive porosity was detected, with Ra values presenting no statistically significant difference from group B. In group B after 10 s, the extent of deproteination was enhanced, reaching a plateau between 30 s and 60 s, and attaining a maximum after 120 s. Tubule diameter, intertubular porosity, and Ra were increased; intertubular dentin area was reduced. For both groups after 40 s of treatment, the mineral to matrix ratio recorded was similar to smear-layer-free sectioned dentin. CONCLUSION: The results of the present study imply that deproteination of mineralized or acid-etched dentin surfaces within a clinically relevant time frame may provide methods for bonding to dentin alternative to conventional technique-sensitive dentin hybridization.

Dentin surface treatment without acids.

Enhancement of the adhesiveness of dental restoratives, such as composite resins, has been clinically essential. A key point in enhancing adhesion is how to treat the dentin surface before bonding. We recently attempted to use an inorganic and non-acidic salt solution for pretreatment to dentin. We paid attention to the salting-in effect of rhodanides which promotes swelling of collagen and gelatin. For pretreatment, we used potassium thiocyanate (KSCN) solution. This study morphologically evaluated the effect of treatment of dentinal smear layer with rhodanides in combination with cross-linking agents such as ferric chloride. Scanning electron microscopy revealed effective removal of the smear layer on the treated dentin surface and obturation of dentinal plugs. Addition of the cross-linking agents to KSCN solution was more effective for pretreatment.