Evaluation of the Smear Layer and Hybrid Layer in Noncarious and Carious Dentin Prepared by Air Abrasion System and Diamond Tips

Purpose: To analyze the smear layer and the hybrid layer in noncarious and carious dentin prepared by different cutting instruments and restored with composite resin. Study design: Cavities were randomly prepared in 160 specimens (noncarious and artificial carious dentin) by high-speed diamond tips (KG Sorensen 1013), air abrasion system (Prepstart, Danville Engineering), ultrasonic tip (CVDentus 8.3231-1), and ultrasonic tip associated with ultrasonic cavitation by water for 10 s. Half of the cavities in each group were conditioned with 37% phosphoric acid for 15 s. The amount of smear layer and dentinal tubules present were analyzed using scanning electron microscopy and graded from 0 to 3. Cavities were prepared in another 20 noncarious specimens and 20 carious specimens and restored with adhesive composite resin system. The restorations were hemisected longitudinally and analyzed using scanning electron microscopy to evaluate the hybrid layer and resinous prolongation characteristics, using scores ranging from 1 to 6. Results: The data were statistically analyzed using Kruskal-Wallis and Dunn tests at 5% of significance level. There was evidence that the most efficient smear layer removal was the acid etching in the noncarious dentin and the water ultrasonic cavitation in the carious dentin. The hybrid layer formed on the noncarious and carious dentin prepared by the ultrasonic tip was more regular than in the specimens prepared by high-speed diamond tip, with many resinous prolongations. Conclusion: The ultrasonic tip seems to be a promising tool for carious dentin cavity preparation. Microsc. Res. Tech. 73:597-605, 2010. (C) 2009 Wiley-Liss, Inc.

Model for the Evaluation of Root Wear by Histometric Analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of the RB-RB/LB-LB mnemonic rule for recording optimally projected intraoral images of dental implants: an in vitro study

Objective: The aim of this study was to evaluate a simple mnemonic rule (the RB-RB/LB-LB rule) for recording intra-oral radiographs with optimal projection for the control of dental implants.Methods: 30 third-year dental students received a short lesson in the RB-RB/LB-LB mnemonic rule. The rule is as follows: if right blur then raise beam (RB-RB), i.e. if implant threads are blurred at the right side of the implant, the X-ray beam direction must be raised towards the ceiling to obtain sharp threads on both implant sides; if left blur then lower beam (LB-LB), i.e. if implant threads are blurred at the left side of the implant, the X-ray beam direction must be lowered towards the floor to obtain sharp threads on both implant sides. Intra-oral radiographs of four screw-type implants placed with different inclination in a Frasaco upper or lower jaw dental model (Frasaco GmbH, Tettnang, Germany) were recorded. The students were unaware of the inclination of the implants and were instructed to re-expose each implant, implementing the mnemonic rule, until an image of the implant with acceptable quality (subjectively judged by the instructor) was obtained. Subsequently, each radiograph was blindly assessed with respect to sharpness of the implant threads and assigned to one of four quality categories: (1) perfect, (2) not perfect, but clinically acceptable, (3) not acceptable and (4) hopeless.Results: For all implants, from one non-perfect exposure to the following, a higher score was obtained in 64% of the cases, 28% received the same score and 8% obtained a lower score. Only a small variation was observed among exposures of implants with different inclination. on average, two exposures per implant (range: one to eight exposures) were needed to obtain a clinically acceptable image.Conclusion: The RB-RB/LB-LB mnemonic rule for recording intra-oral radiographs of dental implants with a correct projection was easy to implement by inexperienced examiners. Dentomaxillofacial Radiology (2012) 41, 298-304. doi: 10.1259/dmfr/20861598

Evaluation of the radiopacity of calcium hydroxide- and glass-ionomer-based root canal sealers

Aim To evaluate the radiopacity of calcium hydroxide-based root canal sealers (Acroseal, Sealapex and Sealer 26), a glass-ionomer-based sealer (Activ GP Sealer) and a zinc oxide and eugenol-based sealer (Intrafill).Methodology Five disc-shaped specimens (10 x 1 mm) were fabricated from each material, according to the International Organization for Standardization (ISO) 6876/2001 standard. After setting of the materials, radiographs were taken using occlusal films and a graduated aluminum step-wedge varying from 2 to 16 mm in thickness. The dental X-ray unit (GE1000) was set at 50 Kvp, 10 mA, 18 pulses s(-1) and distance of 33.5 cm. The radiographs were digitized and the radiopacity compared with that of the aluminum step-wedge, using WIXWIN-2000 software (Gendex). Data (mm Al) were submitted to ANOVA and Tukey test.Results Intrafill was the most radiopaque material (7.67 mm Al) followed by Sealer 26 (6.33 mm Al), Sealapex (6.05 mm Al) and Acroseal (4.03 mm Al). Activ GP was the least radiopaque material (1.95 mm Al, P < 0.05).Conclusions The sealers evaluated in this study had different radiopacities. However, except for the glass-ionomer-based sealer, all materials had radiopacity values above the minimum recommended by the ISO standard.

Scanning electron microscopy evaluation of the hard tissue barrier after pulp capping with calcium hydroxide, mineral trioxide aggregate (MTA) or ProRoot MTA

The aim of this study was to investigate the morphology and localisation of calcium hydroxide- and mineral trioxide aggregate (MTA)-induced hard tissue barriers after pulpotomy in dogs' teeth. Pulpotomies were performed on maxillary and mandibular premolars of five dogs. The teeth were assigned into three groups according to the pulp-capping agent used. The pulpal wounds were capped with calcium hydroxide (Ca(OH)(2) - control), MTA or ProRoot MTA, and the cavities were restored with amalgam. After a 90-day follow-up period, the dogs were euthanised and the teeth were examined under scanning electron microscopy (SEM). An image-processing and analysis software was used to delimit the perimeters of the root canal area and the hard tissue barrier to determine the percentage of root canal obliteration. SEM data were used to assess the morphology, localisation and extension of the reparative hard tissue barriers. ProRoot MTA was statistically different from MTA and Ca(OH)(2) (P < 0.05) regarding tissue barrier morphology. Localisation data showed that ProRoot MTA was significantly different from Ca(OH)(2) (P < 0.05) and similar to MTA (P > 0.01; P > 0.05). No statistically significant difference (P > 0.01; P > 0.05) was observed between MTA and Ca(OH)(2). A larger number of complete (centroperipheral) hard tissue barriers with predominance of dentinal tubules was observed to the ProRoot MTA when compared with the Ca(OH)(2) group.

Evaluation of fungal adherence to plasma-modified polymethylmethacrylate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of marginal microleakage in Class II cavities: Effect of microhylolrid, flowable, and compactable resins

Objective: the goal of the present study was to evaluate the microleakage on the cementum/dentin and enamel surfaces in Class 11 restorations, using different kinds of resin composite (microhybrid, flowable, and compactable). Method and materials: Forty human caries-free molars were extracted and selected. Eighty Class 11 standardized cavities were made in the cervical wall at the cementoenamel junction (CEJ) and at the mesial and distal surfaces. The teeth were divided into four groups: G1 - adhesive system + microhybrid resin composite Z100; G2 - adhesive system + compactable resin composite Prodigy Condensable; G3 - adhesive system + flowable resin composite Revolution + Z1 00 resin composite; G4 - adhesive system + Revolution fluid resin + compactable resin composite Prodigy Condensable. The adhesive system used in this study was Scotchbond Multi-Purpose Plus. The specimens were thermocycled in baths of 5degreesC and 55degreesC for 1,000 cycles and immersed in 50% silver nitrate solution. The specimens then were sectioned and evaluated on degree of dye penetration. Results: the results were evaluated using the nonparametric Kruskall-Wallis test, which showed a statistically significant difference between groups G1 and G4, G2 and G4, and G3 and G4. Conclusions: None of the materials was able to eliminate the marginal microleakage at the cervical wall; the application of a low-viscosity resin composite combined with a compactable resin composite significantly decreased the microleakage.

Radiopacity evaluation of new root canal filling materials by digitalization of images

The aim of this study was to evaluate the radiopacity of five root canal filling materials (AH Plus, Intrafill, Roeko Seal, Epiphany, and EndoRez). Following the International Organization of Standardization 687612001, five circular specimens (10 X 1 mm) were made from each material. After the material set, radiographs were made using occlusal film and a graduated aluminum step-wedge varying in thickness from 2 to 16 mm. The dental X-ray unit (GE1000) was set at 50 Kvp, 10 mA, 18 pulses/second, and distance of 33.5 cm. The radiographs were digitized, and the radiopacity was compared with the aluminum step-wedge, using WIXWIN-2000 software (Gendex). Data (mm Al) were analyzed using ANOVA and Tukey tests. AH Plus and Epiphany were the most radiopaque materials (9.8 and 8.8 mm Al, respectively), followed by EndoRez (7.2 mm Al). Roeko Seal and Intrafill presented the lowest radiopacity values (5.7 and 6.1 mm Al, respectively). Although the materials evaluated demonstrated different radiopacities, all had values above the minimum recommended by the international Organization of Standardization.

Evaluation of the propylene glycol association on some physical and chemical properties of mineral trioxide aggregate

Duarte MAH, Alves de Aguiar K, Zeferino MA, Vivan RR, Ordinola-Zapata R, Tanomaru-Filho M, Weckwerth PH, Kuga MC. Evaluation of the propylene glycol association on some physical and chemical properties of mineral trioxide aggregate. International Endodontic Journal, 45, 565570, 2012. Abstract Aim To evaluate the influence of propylene glycol (PG) on the flowability, setting time, pH and calcium ion release of mineral trioxide aggregate (MTA). Methodology Mineral trioxide aggregate was mixed with different proportions of PG, as follows: group 1: MTA + 100% distilled water (DW); group 2: MTA + 80% DW and 20% PG; group 3: MTA + 50% DW and 50% PG; group 4: MTA + 20% DW and 80% PG; group 5: MTA + 100% PG. The ANSI/ADA No. 57 was followed for evaluating the flowability and the setting time was measured by using ASTM C266-08. For pH and calcium release analyses, 50 acrylic teeth with root-end cavities were filled with the materials (n = 10) and individually immersed in flasks containing 10 mL deionized water. After 3 h, 24 h, 72 h and 168 h, teeth were placed in new flasks and the water in which each specimen was immersed had its pH determined by a pH metre and the calcium release measured by an atomic absorption spectrophotometer with a calcium-specific hollow cathode lamp. Data were analysed by using one-way anova test for global comparison and by using Tukeys test for individual comparisons. Results The highest value of flowability was observed with MTA + 20% DW and 80% PG and the lowest values were found with MTA + 100% DW. They were significantly different compared to the other groups (P < 0.05). The presence of PG did not affect the pH and calcium release. The MTA + 100% PG favoured the highest (P < 0.05) pH and calcium release after 3 h. Increasing the PG proportion interfered (P < 0.05) with the setting time; when used at the volume of 100% setting did not occur. Conclusion The addition of PG to MTA-Angelus increased its setting time, improved flowability and increased the pH and calcium ion release during the initial post-mixing periods. The ratio of 80% DW 20% PG is recommended.

Cephalometric Evaluation of Pharyngeal Airway Space Changes in Class III Patients Undergoing Orthognathic Surgery

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Radiopacity evaluation of root-end filling materials by digitization of images

The purpose of this study was to evaluate the radiopacity of 5 root-end filling materials (white MTA-Angelus, grey MTA-Angelus, IRM, Super EBA and Sealer 26). Five specimens (10 mm diameter X 1 mm thickness) were made from each material and radiographed next to an aluminum stepwedge varying in thickness from 2 to 16 mm. Radiographs were digitized and the radiopacity of the materials was compared to that of the aluminum stepwedge using VIXWIN 2000 software in millimeters of aluminum ( mm Al). Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. Radiopacity values varied from 3 mm Al to 5.9 mm Al. Sealer 26 and IRM presented the highest radiopacity values (p<0.05), while white/grey MTA and Super EBA presented the lowest radiopacity values (p<0.05). The tested root- end filling materials presented different radiopacities, white/grey MTA and Super EBA being the least radiopaque materials.

Evaluation of the analgesic and antiedematogenic activities of Quassia amara bark extract

We evaluated the possible antiedematogenic, antinociceptive and/or sedative effects of four different extracts obtained from the bark of Quassia amara namely, 70% ethanol (70EtOH), 100% ethanol (100EtOH), dichloromethane (DCM) and hexane extracts (HEX). The oral administration (100, 250 and 500 mg/kg) of these extracts did not show significant effects in any experiment. However, when administered intraperitoneally, the HEX extract decreased the paw edema induced by carrageenan, showed antinociceptive effects on the hot-plate test and on acetic acid-induced writhing, and showed sedative effects on pentobarbital-induced sleep. Naloxone did not reverse the antinociceptive effect of this extract. In conclusion, although the mechanisms are uncertain, the results demonstrated that these effects are apparently related to sedative and muscle relaxant or psychomimetic activities of the HEX extract of the plant. (C) 2002 Elsevier B.V. Ireland Ltd. All rights reserved.

Evaluation of pyraclostrobin and acibenzolar-S-methyl on common bacterial blight of snap bean

Assays were done under greenhouse conditions in order to evaluate the effect of pyraclostrobin (0.0375, 0.0750 and 0.150 mL.L-1) and acibenzolar-S-methyl (ASM) (0.025 g.L-1) in common bacterial blight on leaves of snap beans cultivar Braganca. These chemicals were sprayed at three different times: five days before; five days before + five days after; and five days after leaf inoculation with an isolate of Xanthomonas axonopodis pv. phaseoli. They were determinate the levels of polyphenoloxidase, peroxidase and total soluble proteins on inoculated and non-inoculated leaves of snap beans sprayed with pyraclostrobin (0.075 g.L-1) and ASM (0.025 g.L-1). All concentration of pyraclostrobin and ASM reduced the area under the disease progress curve (AUDPC) on leaves of snap beans, and the least AUDPC value was observed when this products were sprayed five days before + five days after inoculation. Higher levels of polyphenoloxidase, peroxidase and the total soluble proteins were observed on leaves sprayed with pyraclostrobin or ASM.

Evaluation of antimutagenic activity and mechanisms of action of beta-glucan from barley, in CHO-k1 and HTC cell lines using the micronucleus test

Due to the need to identify new antimutagenic agents and to determine their mechanism of action, the present study examined the mechanism of action of the P-glucan with regard to antimutagenicity using the micronucleus assay in CHO-kl and HTC cell lines. The mutagenicity experiments were performed with three different concentrations of P-glucan (5, 10, and 20 mu g/mL), in wich only the highest dose showed mutagenic activity. In the antimutagenicity experiments, the same concentrations of P-glucan were combined with a mutagenic agent, methylmethane sulfonate, or 2-aminoanthracene, using four different treatment protocols: pre-treatment, simultaneous treatment (simple and with pre-incubation), and post-treatment. The results indicate that the CHO-kl cell line treated with MMS presented a chemopreventive activity for all the doses of P-glucan in the different treatment protocols, except for the lowest dose in post-treatment. When HTC cell line treated with MMS is analysed, a chemopreventive activity can be verified for the highest dose in both pre- and post-treatment. For the simple simultaneous treatment, the three doses demonstrated efficacy, while for the simultaneous treatment with pre-incubation only the intermediate concentration was effective. In HTC treated with 2AA both the lowest dose in the pre-treatment protocol and the post-treatment protocol did not show efficacy in preventing DNA damage. The evaluation of the different protocols and the damage decrease percentages observed suggest that P-glucan has both desmutagenic and bioantimutagenic activity. It is necessary, however, to note that efficacy and mechanism of action are subject to variation when compared the two cell lines, since in HTC, representing a drug-metabolizing system, this substance can show a diminished chemopreventive capacity. (c) 2006 Elsevier Ltd. All rights reserved.

Action of permethrin on Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) semi-engorged females: Morpho-physiological evaluation of salivary glands

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)