Showing papers by "Franklin Garcia-Godoy published in 2010"

Indirect pulp treatment in primary teeth: 4-year results.

Abstract: Purpose To evaluate clinical and radiographic outcomes of indirect pulp treatment (IPT) in primary molars after long-term function (up to 60 months). Methods Teeth with deep carious lesions without signs and symptoms of irreversible pulpitis were divided by random allocation into two groups, according to the capping material utilized over demineralized dentin: experimental group (1): self-etching adhesive system (Clearfil SE Bond); and control group (2): calcium hydroxide liner (Dycal). Both groups were filled with resin composite (Z250) and submitted to a clinical and radiographic monitoring period until exfoliation. Results After the follow-up period (up to 60 months), no statistical difference was found between groups (P= 0.514). The overall success rate reached 78%. The failures occurred after the first year period recall.

Effect of staining solutions on discoloration of resin nanocomposites.

Abstract: Purpose To examine the effect of staining solutions on the discoloration of resin nanocomposites.

Direct and transdentinal antibacterial activity of chlorhexidine.

Abstract: PURPOSE To evaluate the antibacterial effect of different chlorhexidine (CHX) concentrations against Streptococcus mutans using the agar-diffusion method with and without human dentin discs placed between the bacteria and the test substances. METHODS For the direct application (agar-well technique), a base layer containing 15 mL of BHI agar and 300 microL of S. mutans inoculum (10(9) cfu/mL) was prepared in Petri dishes. Six wells per dish were made at equidistant points and immediately filled with CHX gels (0.12%, 0.2%, 1% and 2%), 35% phosphoric acid and pure natrosol (n = 6 wells/substance). Paper discs soaked in sterile distilled water served as control group (n = 6). For the indirect application (transdentinal diffusion), 0.2 mm- and 0.5 mm-thick human dentin discs (36 discs/thickness) had the hydraulic conductance determined, which allowed the homogeneous allocation of them to the experimental and control groups. The discs were placed at equidistant points on the Petri dishes containing BHI with the S. mutans inoculum (six discs per dish; one per substance) with the pulpal side in contact with the bacteria. In the discs treated with CHX gels, dentin surface was etched with H3PO4 and rinsed with distilled water before CHX gel application for 1 minute. After both direct and indirect application, the dishes were incubated for 24 hours and the bacterial growth inhibition zones formed around the wells and dentin discs were measured. Data were analyzed statistically by the non-parametric Kruskal-Wallis and Mann-Whitney tests at 5% significance level. RESULTS In the direct test, all CHX concentrations presented a dose-dependent antibacterial activity against S. mutans. In the indirect test, there were statistically significant differences (P < 0.05) among all groups and the largest microbial growth inhibition zones were observed when 2% CHX was applied on 0.2 mm-thick discs (P < 0.05). It was concluded that all evaluated CHX gels exhibited both direct and transdentinal antibacterial activity against S. mutans. This effect of CHX was strongly influenced by the CHX concentration as well as the dentin barrier thickness.

Comparison of fracture resistance of bonded glass fiber posts at different lengths.

Abstract: PURPOSE To evaluate in vitro the fracture resistance of quartz fiber posts for three different dowel lengths. METHODS 30 single-rooted human premolars with similar root length and diameter were endodontically treated and randomly divided into three experimental groups (n = 10) according to the post space depth created: (1) 5 mm; (2) 7 mm; (3) 9 mm. Quartz fiber posts (Endo Light post) were cemented using a dual cured resin cement with its adhesive system (Prime & Bond NT + Fluorocore 2). After 24 hours, specimens were embedded in acrylic resin and loaded under continuous compressive force at the extruding coronal part of the post (45-degree angle) to the long tooth axis (crosshead speed: 0.75 mm/minute). Forces at fracture (Newtons) were recorded. One-way ANOVA and Tukey tests were used for the statistical analysis (P < 0.05). RESULTS Mean strength values (SD) were: (1) 40.52 (3.14); (2) 41.68 (5.31); (3) 44.88 (6.77), respectively. No statistically significant differences were found among the groups.

Sealing properties of a calcium aluminate luting agent.

Abstract: Purpose To determine the self-sealing properties of Ceramir C&B, a new calcium aluminate-based luting material and to compare it to two commercially available cements, using a bacterial model system. Methods 30 premolars were prepared in a standardized fashion with a total angle of convergence of approximately 10-12 degrees for complete cast restorations. All margins were placed in dentin. Gold copings were fabricated in a Type III alloy using standardized laboratory methods. Thirty teeth were randomly assigned to three groups of 10: Group 1: Ceramir C&B (CM), a calcium aluminate/glass ionomer hybrid (formerly XeraCem), Group 2: Ketac-Cem (KC), a glass-ionomer cement (control) and Group 3: Rely X Luting Plus (RX), a resin-modified glass-ionomer cement. After cementation the samples were allowed to bench set for 10 minutes, after which they were subjected to thermal cycling (x2000, between 5 and 55 degrees C, dwell time 35 seconds) and then stored in sterile phosphate buffer for 7 days at 37 degrees C. Subsequently the occlusal surface was carefully reduced exposing the dentin. Finishing on wet sand paper removed the gold flash from grinding. After sterilization the specimens were subjected to bacterial microleakage in a dual chamber apparatus for a period of 60 days. Turbidity was recorded daily. The data were analyzed using the Kaplan-Meyer survival analysis and the log-rank test (P Results A statistical analysis demonstrated that the groups cemented with CM and RX showed no significant difference in microleakage patterns (P>0.05), while both recorded significantly lower microleakage scores (P

Evolution of apical formation on immature necrotic permanent teeth.

Abstract: Purpose To evaluate the evolution of apical formation on 28 necrotic immature permanent teeth treated with calcium hydroxide at different stages of root development. Methods Apical formation in 28 necrotic incisors was carried out (27 upper and one lower incisors), in children between the ages of 6 and 13 years old (11 males, 10 females). Following anesthesia and rubber dam isolation, the chamber was opened and the coronal and root pulp tissue was removed. Next, after measuring the canal, the root canal was irrigated with 5% sodium hypochlorite. Once the canal was dried, it was filled with the CaOH2 powder mixed with physiologic saline solution to a dense consistency but malleable. This paste was compressed into the canal using a cotton pellet. The canal was completely filled up to the apex. Finally, the cavity opening was sealed with zinc oxide-eugenol (IRM) and glass-ionomer (Vitrebond). Follow-up appointments were made every 3 months in order to evaluate the evolution of the periapical radiolucency and the formation of the apical barrier. Results The duration of the apical induction was 8.6 +/- 5.36 months. Increase or lack of growth in the length of the root canal and the type of root end closing was as follows: cementoid tissue (85.72%); osseous tissue (14.28%), with a 100% overall success rate. The evolution of these teeth was monitored over a 2-year period with re-infections occurring in 7.1 percent of the cases.

Effect of light-curing units on the thermal expansion of resin nanocomposites.

Abstract: Purpose To examine the thermal expansion of resin nanocomposites after light-curing using different light-curing units. Methods Four different resin nanocomposites and four different light-curing units [quartz-tungsten-halogen (QTH), light emitting diode (LED), laser, and plasma arc] were chosen. Metal dies were filled with resin to make specimens and light-cured. The light intensity and light-curing time of the QTH and LED light-curing units were 1000 mW/cm2 and 40 seconds, 700 mW/cm2 and 40 seconds for the laser, and 1600 mW/cm2 and 3 seconds for the plasma arc. The coefficient of thermal expansion (CTE) was evaluated using a thermomechanical analyzer (TMA) at temperatures ranging from 30-80 degrees C. Results The CTE of the resin nanocomposites tested ranged from 28.5 to 65.8 (x 10(-6)/ degrees C), depending on the product and type of light-curing unit used. Among the specimens, Grandio showed the lowest CTE. The specimens cured using the plasma arc unit (Apollo 95E) showed the highest CTE. There was a linear correlation between the CTE and filler content (vol%) (R: -0.94-0.99 depending on the light-curing unit). The results may suggest a careful selection of the light-curing unit because there was more expansion in the specimens cured using the plasma arc unit than those cured by the other units.

Effect of an 8.0% arginine and calcium carbonate in-office desensitizing paste on the shear bond strength of composites to human dental enamel.

Abstract: PURPOSE To evaluate the effect of 8.0% arginine and calcium carbonate, in-office desensitizing paste (Colgate Sensitive Pro-Relief Desensitizing Paste) on the shear bond strength of composites to human dental enamel. METHODS Two resin composites (Filtek Supreme, Premise) and human dental enamel were used. 16 samples per composite were prepared. Caries-free extracted human molars, not older than 3 months, and stored in distilled water were used for this portion of the experiment. Buccal and lingual surfaces were polished with high polishing pastes to create a uniform flat surface area to which the cylindrical composite samples were bonded. After polishing, the samples were rinsed in tap water and stored at 100% relative humidity. The resin composites were used to form cylindrical samples 3 mm x 1.6 mm, which were light-cured with a Demetron curing light according to the manufacturers' instructions. For each composite, 32 surfaces were used; 16 were a control group with the enamel polished with a water slurry of flour of pumice. The experimental group had the enamel polished with the 8.0% arginine and calcium carbonate desensitizing paste, using disposable latex free prophy cups with a slow speed hand piece at 3,000 rpm using moderate to light pressure, according to manufacturer's instructions. The composite cylinders were bonded to the enamel with their respective etching agents and adhesives and left in distilled water for 48 hours, after which the samples were sheared with an Instron testing machine at 0.5 mm/minute. After shearing, all samples were analyzed with a stereo microscope to evaluate failure pattern (failure at the enamel surface, failure at the composite surface, or mixed failure, at both enamel and composite surfaces). SEM images of selected surfaces were made to depict the overall morphology of the surface of dental materials used after 8.0% arginine and calcium carbonate desensitizing paste, application and shear strength tests. ANOVA and Student-Newman-Keuls tests (P < 0.05) were used to evaluate the difference among the groups. RESULTS The 8.0% arginine and calcium carbonate desensitizing paste did not have a significant effect on the shear bond strength of the composites tested to enamel.

Brushing abrasion of dentin: effect of diluent and dilution rate of toothpaste.

Abstract: PURPOSE To determine whether toothpaste diluent type and dilution rate influence abrasion of dentin. METHODS Slabs of human root dentin (4 x 3 x 2 mm) were embedded in epoxy resin, ground and polished. Adhesive tape was placed on the specimen's surface leaving an exposed central area of 1 x 4 mm. Specimens (n = 15) were then brushed for 1,000 strokes in a reciprocal action brushing simulator using toothpaste that had been diluted in a carboxymethylcellulose-based artificial saliva (CMC) or deionized water (DW) from 1:1 to 1:4 (toothpaste:diluents, in weight). Control groups were brushed with undiluted toothpaste, CMC-based saliva or DW only. Brushing simulation was run at 300 g load at 37 degrees C. After brushing, adhesive tape was removed and wear analyzed by optical profilometry. RESULTS One-way ANOVA (P < 0.0001) and Tukey's test revealed that, in general, wear depth (microm) declined with increasing dilution, regardless of the diluent. Brushing with CMC- or DW-only caused the least abrasion.

Evolution and prognosis of necrotic primary teeth after pulpectomy.

Abstract: Purpose To study the evolution of 308 necrotic primary teeth after pulpectomy technique with resorbable paste (Kri-1 + calcium hydroxide + metacresol-formaldehyde) after 30 months. Methods 134 children between 2-9 years were included, among which they had 348 pulpectomized teeth. Out of these 348 teeth, 308 had necrotic pulp and were included in the study. The filling material consisted of a paste based on Walkhoff's master formula and consisted of the combination of Kri-1a (80.8% iodoform, 2.025% parachlorophenol, 1.215% menthol, 4.68% camphor and excipient 15 mg), pure calcium hydroxide and metacresol formaldehyde (metacresol 20 mg, formaldehyde 20 mg, eugenol 20 mg, eucalyptus 6 mg and excipient 40 mg). Root canal filling was performed in one session by one operator. Results Pain, swelling, and fistula resolution was observed in most cases at the first recall. Progressive remission of radiolucent areas was also observed. A relationship between fistula and radiolucency in pre-treated furcation area was observed, and, in some cases, premature eruption of permanent teeth was recorded. Only two cases out of 308 treated teeth required extraction.

Dentin hypersensitivity: the effects of an arginine-calcium carbonate and fluoride desensitizing dentifrice.

Abstract: Purpose: To provide a brief overview of the diagnosis, epidemiology, etiology and clinical management of dentin hypersensitivity, to discuss technical approaches to relieve sensitivity, with special emphasis on dentin tubule occlusion and the clinical evidence for efficacy of desensitizing toothpastes based upon this approach, and to summarize the science behind a new dentifrice technology, based upon arginine and calcium carbonate, and the clinical evidence which proves that it delivers both instant and lasting relief of dentin hypersensitivity. Results: Clinical studies have shown that a new toothpaste, containing arginine and calcium carbonate (known as Pro-Argin technology) with 1450 ppm fluoride, offers clinically proven instant and lasting relief of dentin hypersensitivity. Three 8-week clinical studies have shown that this new toothpaste provides statistically significantly superior efficacy in reducing sensitivity to market leading desensitizing toothpastes containing 2% potassium ion. Importantly, three further clinical studies have shown that a single direct topical application of toothpaste to sensitive teeth, using a fingertip or cotton swab followed by 1 minute of massage, resulted in instant relief of dentin hypersensitivity and that the relief was maintained with subsequent twice-daily brushing. Mechanism of action studies have shown that this technology physically seals dentin tubules with a plug that contains arginine, calcium carbonate and phosphate. This plug, which is resistant to normal pulpal pressures and to acid challenge, effectively reduces dentin fluid flow and thereby relieves sensitivity. A new whitening variant of this desensitizing toothpaste, containing the Pro-Argin technology, fluoride and a high cleaning calcium carbonate system, has now been clinically and scientifically validated. This toothpaste works by the same mechanism of action as its non-whitening counterpart and is clinically proven to provide both instant and lasting relief of sensitivity, while providing proven efficacy in removal of extrinsic stains. No difference in desensitizing efficacy was observed between the whitening and nonwhitening versions. (Am J Dent 2010;23 Sp Is A:3A-13A). CLINICAL SIGNIFICANCE: The results of a series of clinical studies support the conclusion that a new toothpaste containing 8.0% arginine, a high cleaning calcium carbonate system, and 1450 ppm fluoride provides statistically significant relief of dentin hypersensitivity immediately after direct topical application and during regular twice daily brushing, as well as statistically significant removal of extrinsic stains. : Dr. Diane Cummins, Colgate-Palmolive Technology Center, 909 River Road, Piscataway, NJ 08855-1343, USA; E: diane_cummins@colpal.com