[Show abstract][Hide abstract] ABSTRACT: This in vitro study evaluated the efficacy of toothpastes containing abrasive and chemical whitening agents in reducing the extrinsic discoloration of dental enamel. Sixty slabs of dentin from human teeth were sealed so that only the enamel surface was exposed. The enamel surfaces were photographed for initial color assessment. Staining was performed by immersing the dental slabs in 0.2% chlorhexidine solution for 2 minutes and then in black tea for 60 minutes. This process was repeated 15 times. Photographs were taken at the end of the staining process, and the slabs were divided into 5 groups (n = 12), 3 to be brushed with toothpastes containing chemical whitening agents (2 containing phosphate salts and 1 containing phosphate salts plus hydrogen peroxide) and 2 to represent control groups (ordinary/nonwhitening toothpaste and distilled water). The dental slabs were subjected to mechanical toothbrushing with toothpaste slurry or distilled water, according to each group's specifications. After brushing, more photographs were taken for color analysis. The results showed a significant reduction in luminosity after the staining process in addition to an increase in the colors red and yellow (P < 0.001). After brushing, there was a significant increase in luminosity and a reduction in both red and yellow (P < 0.001). However, there was no observed difference between the changes in color values in dental enamel slabs brushed with whitening toothpastes and the changes found in slabs brushed with ordinary toothpaste. The whitening toothpastes did not outperform an ordinary toothpaste in the removal of extrinsic staining.
[Show abstract][Hide abstract] ABSTRACT: Objective:
Mouthrinsing with antacids, following erosive episodes, have been suggested as a preventative strategy to minimize tooth surface loss due to their neutralizing effect. The purpose of this in situ study was to evaluate the effect of an antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate in controlling simulated erosion of enamel of intrinsic origin.
The experimental units were 48 slabs (3×3×2mm) of bovine enamel, randomly divided among 12 volunteers who wore palatal appliances with two enamel slabs. One of them was exposed extra-orally twice a day to 25mL of a hydrochloric acid (HCl) solution (0.01M, pH 2) for 2min. There were two independent phases, lasting 5 days each. In the first phase, according to a random scheme, half of the participants rinsed with 10mL of antacid suspension (Gaviscon(®), Reckitt Benckiser Healthcare Ltd.), while the remainder was rinsed with deionized water, for 1min. For the second phase, new slabs were inserted and participants switched to the treatment not received in the first stage. Therefore, the groups were as follows: (a) erosive challenge with HCl+antacid suspension; (b) erosive challenge with HCl+deionized water (DIW); (c) no erosive challenge+antacid suspension; (d) no erosive challenge+DIW. Specimens were assessed in terms of surface loss using optical profilometry and Knoop microhardness. The data were analyzed using repeated measures two-way analysis of variance and Tukey's tests.
Compared to DIW rinses, surface loss of enamel was significantly lower when using an antacid rinse following erosive challenges (p=0.015). The Knoop microhardness of the enamel was significantly higher when the antacid rinse was used (p=0.026).
The antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate, rinsed after erosive challenges of intrinsic origin, reduced enamel surface loss.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the effect of chlorhexidine and ethanol application on the push-out bond strength and bond durability of fiber posts cemented with an etch-and-rinse adhesive system/resin cement to intraradicular dentin.
Fifty-four bovine roots were shaped for the cementation of a fiberglass post and received the application of 37% phosphoric acid. They were then randomly divided into three groups, according to the type of dentin treatment (n = 18) performed: no treatment (control group), 100% ethanol, or 2% chlorhexidine. Next, the adhesive system (Adper Scotch Bond Multipurpose Plus, 3M ESPE) was applied to the dentin, according to the manufacturer's instructions. Glass fiber posts were cemented with dual resin cement (Rely X ARC, 3M ESPE). After 48 hours, the specimens were serially sectioned for push-out test analysis, providing two slices from each root third (cervical, medium and apical), one of which was tested immediately and the other stored in distilled water for 180 days. The data were analyzed with three-way analysis of variance (ANOVA) for repeated measures and Tukey's test at a 5% significance level.
Intraradicular treatment with chlorhexidine yielded the highest bond strength means, followed by ethanol treatment. The control group presented the lowest bond strength means. Water storage exerted no effect on bond strength values.
Both chlorhexidine and ethanol improved push-out bond strength to intraradicular dentin, with the former providing the best results, regardless of the storage time.
The application of 2% chlorhexidine or 100% ethanol may be an important step that can be taken to enhance bond strength of fiber posts to intraradicular dentin, when dual resin cements are used.
The journal of contemporary dental practice 09/2015; 16(7):547-53. DOI:10.5005/jp-journals-10024-1720
[Show abstract][Hide abstract] ABSTRACT: The aim of this in vitro study was to evaluate the calcium and phosphorus concentrations in enamel surfaces before, during, and after treatment with in-office 35% hydrogen peroxide bleaching agents with 2% calcium gluconate (WCa) or without calcium gluconate (W). Twenty sound human third molars were divided into 2 groups of 10. The bleaching agents were applied to the tooth surfaces in accordance with the manufacturer's instructions: WCa, 40 minutes per day at 3 sessions with 7-day intervals; W, 3 × 15 minutes per day at 3 sessions with 7-day intervals. Enamel microbiopsies were performed prior to the bleaching treatment, immediately after each bleaching session (first, second, and third applications), and 7 and 14 days following the last bleaching treatment. The concentration levels of calcium and phosphorus in the microbiopsy specimens were recorded spectrophotometrically. There was a statistically significant decrease in the calcium concentration 7 days after the last bleaching treatment, but there was a recovery to baseline values at 14 days, regardless of the bleaching agent used (WCa and W). When W was used, there was no difference in the phosphorus concentration over time. The phosphorus concentration in the WCa group decreased after the third application, showing a significant difference from the W group at this time. However, an increase in the phosphorus concentration was observed in the posttreatment period, and no significant differences were observed between values at baseline and those at 14 days posttreatment. The in-office bleaching gel containing 2% calcium gluconate did not affect the calcium and phosphorus concentrations in enamel as compared to a calcium-free bleaching agent.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to evaluate the inhibition of demineralization around enamel-dentin/restoration interface after dentin pretreatment with 2.5 % titanium tetrafluoride (TiF4).
Forty dental class V cavities at the cementoenamel junction were distributed into four groups (n = 10), according to the presence or absence of TiF4 and to the adhesive system (Clearfil SE Bond/CL and Adper EasyOne/AD), and restored with a resin composite. A dynamic pH cycling model was used to induce the development of artificial caries lesions. After sectioning the dental blocks, Knoop microhardness tests were performed at different depths (20, 40, and 60 μm from the occlusal margin of the restoration) and at different distances (100, 200, and 300 μm from the adhesive interface). Repeated measures three-way analysis of variance (ANOVA) and Tukey's test were used (α = 0.05).
For enamel, there were no differences in the microhardness values for CL, AD, and TiF4-AD at depths, regardless of the distances. Considering each depth, there were no significant differences among treatments. For dentin, ANOVA showed no significant interaction among the independent variables treatment*distance*depth (p = 0.994), no significant interaction between treatment*depth (p = 0.722), no significant interaction between treatment*distance (p = 0.265), no significant interaction between depth*distance (p = 0.365), and no significant effect on treatment (p = 0.151), depth (p = 0.067), or distance (p = 0.251).
Dentin pretreatment of the cavity walls with TiF4 before self-etching adhesive systems was not effective in inhibiting demineralization around the enamel-dentin/restoration interfaces.
The mechanism of incorporating fluoride in enamel and dentin of the cavity walls to inhibit demineralization around restorations seems ineffective when using TiF4 as a dentin pretreatment.
[Show abstract][Hide abstract] ABSTRACT: Pleomorphic adenoma (PA) is the most common salivary gland neoplasm, and while mostly benign, recurrences (RPA) and malignant transformation to carcinoma ex-PA (CXPA) do occur. Cell cycle proteins important in its tumorigenesis have been studied as markers for PA with a high risk of RPA or CXPA. The aim of the present study was to investigate cell cycle markers p-16, cyclin D1, CDK4, E2F, and retinoblastoma (Rb) in this context. Expression of p16, cyclin D1, E2F, CDK4, and Rb was studied by immunohistochemistry in 24 cases of PA, 21 of RPA, and 2 of CXPA. The presence of HPV was assessed by in situ hybridization. Immunostaining for p16 and cyclin D1 was negative or weakly positive in most cases of PA while strongly positive in the majority of RPA and both CXPA cases. Staining for Rb and CDK4 was either negative or weakly positive in PA, RPA, and CXPA. Expression of E2F was stronger in RPA and CXPA than in PA. Nuclear reactivity for HPV was not observed in any case. In conclusion, the strong staining for p16, cyclinD1, and E2F in RPA and CXPA, while weak or negative in PA, suggests that these proteins might be involved in recurrence and malignant transformation of PA.
Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 07/2015; 467(3). DOI:10.1007/s00428-015-1804-x · 2.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study evaluated the bond strength of a two-step conventional adhesive system to dentin pretreated with 2.5 % titanium tetrafluoride (TiF4) according to application timing (before or after acid conditioning) and primer/adhesive application method (active or passive).
Dentin surfaces were randomly treated with different adhesive procedures (n = 6): etching with phosphoric acid (PA) + primer/adhesive (Adper Single Bond 2/3M ESPE) actively applied; PA + primer/adhesive passively applied; TiF4 before PA + primer/adhesive actively applied; TiF4 before PA + primer/adhesive passively applied; TiF4 after PA + primer/adhesive actively applied; and TiF4 after PA + primer/adhesive passively applied. A composite block was built onto the tooth, which was sectioned into sticks (adhesive area of approximately 1 mm(2)). Microtensile bond strength tests and the failure mode were determined.
Two-way ANOVA revealed no significant interaction between TiF4 application timing and primer/adhesive application method (p = 0.184). The use of TiF4, before or after PA significantly increased bond strength values (p < 0.001). There was no significant difference in bond strength values when using TiF4 before or after PA. The primer/adhesive application method had no influence on bond strength, regardless of whether TiF4 was used (p = 0.906). Failure mode was predominantly adhesive.
The use of TiF4 promoted higher immediate bond strength to dentin. The conventional adhesive system may be applied either actively or passively, regardless of TiF4 application timing.
Pretreatment with TiF4 increased bond strength in a conventional two-step adhesive system to dentin, regardless of the primer/adhesive application method and the timing of dentin pretreatment.
[Show abstract][Hide abstract] ABSTRACT: The saliva of patients undergoing orthodontic treatment with fixed appliances can potentially present a delay in the diluting, clearing, and buffering of dietary acids due to an increased number of retention areas. The aim of this clinical trial was to compare salivary pH kinetics of patients with and without orthodontic treatment, following the intake of an acidic beverage. Twenty participants undergoing orthodontic treatment and 20 control counterparts had their saliva assessed for flow rate, pH, and buffering capacity. There was no significant difference between salivary parameters in participants with or without an orthodontic appliance. Salivary pH recovery following acidic beverage intake was slower in the orthodontic subjects compared to controls. Patients with fixed orthodontic appliances, therefore, seem to be at higher risk of dental erosion, suggesting that dietary advice and preventive care need to be implemented during orthodontic treatment.
[Show abstract][Hide abstract] ABSTRACT: The aim of the present in vitro study was to evaluate the effect of chlorhexidine, applied before a self-etching adhesive system (Clearfil SE Bond) on microtensile bond strength to superficial and deep dentin (DD), immediately and after six months of water storage (WS). Forty dentin specimens were divided into two groups according to dentin depth: superficial and deep. The specimens were then divided according to the solution to be applied (n = 10): CLX: 2% chlorhexidine (passively applied for 60 s) and NT (no treatment). A self-etching adhesive system was applied according to the manufactures instructions, with composite restorative placed on the dentin surface. After 24 h, dentin–resin blocks were sectioned into beam-shaped specimens that were submitted to microtensile bond strength testing either immediately or after six months of WS. Data were submitted to three-way ANOVA (α = 0.05). Bond strength values for the deep dentin group were significantly lower than those observed for superficial dentin (SD) (p = 0.002), whether chlorhexidine solution had been applied or not. There was no statistical difference in bond strength for specimens tested after 24 h and 6 months of WS. The application of chlorhexidine did not affect immediate and long-term bond strength to dentin. Bond strength in deep dentin was lower than in SD.
Journal of Adhesion Science and Technology 03/2015; 29(12). DOI:10.1080/01694243.2015.1025463 · 0.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose
The aim of this study was to investigate the push-out bond strength (PBS) of resin-relined and non-relined glass fiber posts (GFP) luted to flared root canals.
Material and methods
Root canals of 80 bovine incisors were enlarged to obtain 40 mildly flared and 40 over-flared post spaces. Half of the specimens from each group had the GFP resin-relined, whilst the remainders were not relined. A further 20 root canals were minimally flared and restored with a non-relined GFP (control group). Posts were luted into the root canal space using dual-cure resin cement. Three slices were sectioned from each specimen: one from the coronal third and the others from the middle and apical thirds. PBS test was performed in a universal testing machine at a speed of 0.5 mm/min.
Two-way ANOVA for repeated measures and Tukey's test showed that PBS was affected by the root canal flare and relining procedure (p<0.001). Relining significantly increased the PBS of GFP luted in roots with mildly flared canals when compared to those with excessive widening, regardless of the relining procedure. Relining GFP for over-flared canals had a PBS equivalent to that observed in the control group (minimally flared canal/non-relined GFP). PBS values were higher in the coronal third. No difference was found between the PBS values in the middle and apical thirds.
Depending on the extent of the root canal flare, relined fiber posts may outperform or at least perform as well as posts luted in minimally-flared canals.
International Journal of Adhesion and Adhesives 12/2014; 55. DOI:10.1016/j.ijadhadh.2014.09.003 · 1.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objectives: The aims of this study were to evaluate the effects of: (a) the application method of a 2.5% titanium tetrafluoride aqueous solution (TiF4) to dentin on the microtensile bond strength of a two-step self-etching adhesive system and (b) dentin pretreatment with 2.5% TiF4 on the microtensile bond strength of a two-step self-etching adhesive system to sound and demineralized dentin. Materials and methods: Thirty-two third molars were selected to evaluate the application method for dentin pretreatment with TiF4 (Study I). The occlusal enamel surfaces were removed, the superficial dentin flattened and the teeth divided into four groups according to the application method (n=8): NO-no dentin pretreatment with TiF4; 60A-active application of TiF4 for 60 s; 30A-active application of TiF4 for 30 s; 60P-passive application of TiF4 for 60 s. Twenty-four teeth were used to evaluate the effects of TiF4 on sound and demineralized dentin (Study 2). The occlusal enamel of the teeth was removed and flattened. They were then divided into four groups according to the degree of dentin mineralization (sound or demineralized) and the presence or absence of dentin pretreatment with TiF4 (n=6). For dentin demineralization, the teeth were immersed in demineralizing solution for 1 h and in remineralizing solution for 23 h for 3 days. Dentin pretreatment with 2.5% TiF4 was performed actively for 1 min in Study 2. For Studies 1 and 2, after application of a two-step self-etching adhesive system (Clearfil SE Bond/Kuraray), a composite resin block was built up on the tooth. The tooth-resin samples were cut to obtain specimens with a bonding area of approximately 1 mm(2). Microtensile bond strength testing was performed 24 h later. The fractured test specimens were visually examined to classify the failure mode. Photomicrographs of the tooth/restoration interface were taken using scanning electron microscopy. Results: For Study 1, ANOVA demonstrated no difference between application methods (p=0.784). For Study 2, ANOVA revealed no significant difference in mean bond strength values between sound and demineralized dentin (p=0.1982), or between the presence or absence of TiF4 (p=0.1789). In addition, no significant interaction between the factors (p=0.4284) was observed. The commonnest failure mode for both studies was adhesive. Hybrid layer formation was observed in all TiF4 application methods and degrees of dentin mineralization; however, the use of TiF4, independently of the application method, reduced the number and the extent of resin tags in the hybrid layer. Conclusions: Microtensile bond strength of a self-etching adhesive system to dentin was not influenced by the application method of TiF4. Dentin pretreatment with TiF4 had no influence on the bond strength of the two-step self-etching adhesive system to sound or demineralized dentin, despite the changes in hybrid layer micromorphology.
International Journal of Adhesion and Adhesives 10/2014; 54:159-164. DOI:10.1016/j.ijadhadh.2014.06.005 · 1.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate in vitro the effect of photodynamic therapy (PDT) using LASER or light emitting diode (LED) on cariogenic bacteria (Streptococcus mutans [SM] and Lactobacillus casei [LC]) in bovine dentin.
Twenty five fragments of dentin were contaminated with SM and LC strands and divided into five experimental groups according to the therapy they received (n = 5): C - control (no treatment), SCLED - no dye/LED application (94 J/cm(2)), SCLASER - no dye/LASER application (94 J/cm(2)), CCLED - dye/LED application (94 J/cm(2)) and CCLASER - dye/LASER application (94 J/cm(2)). The dye used was methylene blue at 10 mM. Dentin scrapes were harvested from each fragment and prepared for counts of colony forming units (CFU)/mL. The data were analyzed using Kruskal-Wallis, followed by Student-Newman-Keuls (α =0.05).
Regarding SM, groups CCLASER and CCLED showed a significant reduction in CFU/mL, which was statistically superior to the SCLASER, SCLED and C groups. Regarding LC, the groups CCLASER and CCLED caused a significant reduction in CFU/mL when compared with SCLASER, which showed intermediate values. SCLED and C had a lesser effect on reducing CFU/mL, where the former showed values similar to those of SCLASER.
In conclusion, PDT combined with LASER or LED and methylene blue had a significant antimicrobial effect on cariogenic bacteria in the dentin.
European journal of dentistry 10/2014; 8(4):509-14. DOI:10.4103/1305-7456.143634