[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to evaluate the influence of surface treatments and thermocycling on the microtensile bond strength (μTBS) of self-adhesive resin cement to human enamel and dentin. Eighty human third molars were selected. The crowns of 40 teeth were transversally sectioned, exposing the mid-coronal dentin. The buccal surfaces of the other 40 teeth were grinded to obtain a 5 mm2 flat enamel area. Eighty resin blocks were produced and cemented to the dental surfaces with RelyX Unicem, then grouped according to the surface treatment (n = 10): UnicemC with no conditioning, UnicemP with 37% phosphoric acid/15 s, and UnicemPA with 37% phosphoric acid/15 s plus adhesive bonding (Single Bond 2). There were two control groups, one for enamel and the other for dentin: VR with 37% phosphoric acid/15 s plus adhesive bonding (Single Bond 2) plus Variolink II. The enamel-dentin resin cement blocks were sectioned to produce non-trimmed bar specimens, which were divided into two storage conditions: dry, μTBS immediately after cutting; TC (5,000 x; 5°C/55°C). The samples were submitted to μTBS, and data were statistically analyzed by ANOVA and Tukey's test. The results showed statistical differences between UnicemC and the others. UnicemPA and VR showed better bond strength to dentin during the period before and after thermocycling, respectively. For the enamel, UnicemP showed better bond strength for both situations. Only for UnicemPA did the thermocycling significantly decrease the bond strength values. Within the limits of this study, it could be concluded that the bond strength is influenced by the surface treatments, and that thermocycling decreases the bond strength of all groups, but significantly only for UnicemPA.
[Show abstract][Hide abstract] ABSTRACT: The objective of the study was to evaluate the effect of immediate polishing, after 24 h and after 1 week, on the surface roughness of two micro-hybrid resins (Esthet-X; Opallis) and one nanoparticle resin (Filtek Z350), as well as verifying maintenance of the polish after 1 year, simulated by means of thermal cycling. Forty-three specimens of each material were made and divided into a control group and three experimental groups. The control group specimens received no surface treatment. Group 1 received finishing with an extra-fine diamond drill and posterior polishing with the systems Enhance and PoGo, immediately after polymerization. Group 2 received the same procedures; however, these were carried out after 24 h of storage. Group 3 received the surface treatment after 7 days of storage. After that, the surface roughness was evaluated by a profilometer. After the initial reading, the specimens were submitted to thermal cycling for 10,000 cycles. After thermal cycling, a new roughness reading was taken. The results showed a higher roughness value for the resin Esthet-X, and the resins Opallis and Z350 presented the same roughness values. As regards the time when polishing was performed, specimens polished immediately after polymerization presented higher roughness values in comparison with the other two periods. After thermal cycling, the statistical analysis showed that the Opallis resin polish had been maintained, whereas for the other two resins, there was a significant reduction in surface smoothness. The surface roughness was influenced by the material and also by the period of polishing; the surface roughness of all tested materials were at a clinically acceptable level.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the effects of dentin surface treatments on the tensile bond strength (TBS) of the self-etching primer Clearfil SE Bond (CSE) and the one-step self-etching One-Up Bond F (OUB). The exposed flat dentin surfaces of twenty-four sound third molars were prepared with diamond bur at high-speed, carbide bur at low-speed or wet ground with #600 grit SiC paper. The adhesive systems were applied to the dentin surfaces and light-cured according to the manufacturers' instructions. A 6-mm high composite crown was incrementally built-up and each increment was light-cured for 40 seconds. After being stored in water (37 degrees C/24 h), the samples were serially sectioned parallel to the long axis, forming beams (n = 20) with a cross-sectional area of approximately 0.8 mm(2). The specimens were tested in a Universal Testing Machine at 0.5 mm/min. The cross-sectional area was measured and the results (MPa) were analyzed by two-way ANOVA and Tukey Test (p < 0.05). Overall, the groups treated with CSE exhibited the highest TBS for all surface treatments. Dentin surfaces prepared with carbide bur at low speed reduced TBS in the CSE group; however, OUB was not affected by surface treatments. The effect of surface abrasive methods on TBS was material-dependent.
[Show abstract][Hide abstract] ABSTRACT: Purpose: The aim of this study was to evaluate the surface roughness of four packable composite resins, SureFilTM (Dentsply, Petrópolis, Rio de Janeiro, Brazil), Prodigy CondensableTM (Kerr Co., Orange, CA, USA), Filtek P60TM (3M do Brasil, São Paulo, Brazil), and ALERT® (Jeneric/Pentron, Inc., Wallingford, CT, USA) and one microhybrid composite resin (Filtek Z250TM, 3M do Brasil) after polishing with four finishing systems.
Materials and Methods: Twenty specimens were made of each material (5 mm in diameter and 4 mm high) and were analyzed with a profilometer (Perthometer® S8P, Perthen, Mahr, Germany) to measure the mean surface roughness (Ra). The specimens were then divided into four groups according to the polishing system: group 1–Sof-LexTM (3M do Brasil), group 2–EnhanceTM (Dentsply), group 3–Composite Finishing Kit (KG Sorensen, Barueri, São Paulo, Brazil), and group 4–Jiffy Polisher Cups® (Ultradent Products, Inc., South Jordan, UT, USA). The specimens were polished and then evaluated for Ra, and the data were subjected to analysis of variance, analysis of covariance, and Tukey's test (p= .05).
Results: The mean Ra of SureFil polished with Sof-Lex was significantly lower than that of KG points. Prodigy Condensable polished with Enhance showed a significantly less rough surface than when polished with Sof-Lex. Filtek P60 did not exhibit a significant difference with the various polishing systems. For ALERT the lowest mean Ra was obtained with Sof-Lex and the highest mean Ra with KG points. Regarding Filtek 2250, polishing with KG and Jiffy points resulted in a significantly lower mean Ra than when polished with Enhance.
Conclusions: Packable composite resins display variable roughness depending on the polishing system used; the Sof-Lex disks and Jiffy points resulted in the best Ra values for the majority of the materials tested.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the effectiveness of the clinical use of the gallium-aluminum-arsenium (GaAlAs) laser at the maximum and minimum energies recommended by the manufacturer for the treatment of dentine hypersensitivity.
Dentine hypersensitivity (DH) is a response to a stimulus that would not usually cause pain in a healthy tooth. It is characterized by sharp pain of short duration from the denuded dentin. Its etiology is unknown. The dentin only begins to show sensitivity when exposed to the buccal environment. This exposure can result after removal of the enamel and/or dental cement, or after root denudation. Different treatments are proposed for this disorder.
In this study, 25 patients, with a total number of 106 cases of DH, were treated with GaAlAs low-level laser therapy (LLLT). 65% of the teeth were premolars; 14% were incisors and molars; 6.6% were canines. The teeth were irradiated with 3 and 5 J/cm2 for up to six sessions, with an interval of 72 h between each application, and they were evaluated initially, after each application, and at 15 and 60 days follow-up post-treatment.
The treatment was effective in 86.53% and 88.88% of the irradiated teeth, respectively, with the minimum and maximum energy recommended by the manufacturer. There was a statistically significant difference between DH and after a follow-up of 60 days for both groups. The difference among the energy maximum and minimum was not significant.
The GaAlAs low-level laser was effective in reducing initial DH. A significant difference was found between initial values of hypersensitivity and after 60 days follow-up post-treatment. No significant difference was found between minimum (3 J/cm2) and maximum (5 J/cm2) applied energy.
[Show abstract][Hide abstract] ABSTRACT: A literature review was carried out concerning the possible risks of the use of amalgam in regard to the toxicity of mercury. Despite the fact that the American Dental Association (ADA) and the Food and Drug Administration (FDA) do support the use of amalgam, it is noticed that still today there are controversies regarding its use. In many countries such as in the United States, Sweden and Canada, there are groups which oppose the use of amalgam and they also defend a planned reduction in the odontological practi- ce, mainly due to environmental reasons. We have observed that individuals with amalgam restorations indeed have a higher tran- sitory level of mercury, both in blood and in urine This concentra- tion is not harmful to their health, however. It should be made clear to patients that there are other sources of mercury absorpti- on such as food, cosmetics among others and that we should take the necessary steps as to minimize the contamination of the prac- titioners, the patients as well as the environment. Even though they are aesthetically unsatisfactory, in the long run amalgam res- torations have proven to have an excellent clinical quality. UNITEMS toxicity; mercury; dental amalgam.