No abstract

Tooth-coloured plastic dental fillings secured by adhesives to tooth structures are widely used to fix decayed teeth. Whereas laboratory tests demonstrate rapid deterioration of the ability of the adhesives to stick to dentine, clinical studies show that these fillings are relatively durable. This discrepancy suggests that the parameters used for simulating bond degradation in the laboratory setting do not correlate well with clinical outcomes. The present study examined the long-term tensile bond strength of resin composite fillings performed in real life and under different laboratory-simulated bonding conditions to identify parameters that may be used to forecast the durability of adhesive bonds created in dentine. Fillings placed in vivo were subjected to different periods of intraoral function. In vitro specimens were bonded based on whether simulated pulpal pressure (SPP) or thermomechanical cycling was implemented, and how long the completed fillings were stored in water. Thermomechanical cycling used in combination with long-term water ageing are useful in forecasting the decline in strength of resin-dentine bonds created in vivo. These parameters should be adopted for future evaluations. Conversely, the use of SPP does not appear to be a significant parameter in the simulation of long-term clinical deterioration of bond integrity.

This study is aimed at evaluating the flexural strength (FS), fracture toughness (FT), and diametral tensile strength (DTS) of three resin-modified glass-ionomer cements (RMGICs): Ketac Nano, Riva Light Cure, and Fuji II LC. One hundred twenty specimens were prepared from the RMGIC materials ( n = 10 ). The cements were mixed and inserted into different mould sizes according to the test performed: FS: rectangular Teflon mould ( 32   mm × 3.15   mm × 2   mm ); FT: notchless triangular prism (NTP) Teflon mould ( 6   mm × 6   mm × 6   mm × 12   mm ); and DTS: ring road stainless steel mould ( 6   mm × 3   mm ). Specimens were light cured for 20 seconds on each surface and stored in distilled water at 37 ° C ± 2 ° C for seven days prior to tests. To evaluate the influence of storage in the mechanical properties of the RMGIs, specimens tested for DTS were stored in distilled water at 37 ° C ± 2 ° C for 32 days prior to test. Data were analyzed by ANOVA and Tukey’s test ( α = 0.05 ). Fuji II LC presented significantly higher values for all tests employed when compared to Ketac Nano and Riva LC RMGIs. There was no significant difference on DTS before and after the 32-day storage for each material. Fuji II LC presented superior mechanical properties when compared to Ketac Nano, and Riva LC storage showed no influence on the mechanical properties of the RMGI materials tested.

<p><strong>Objective</strong>: evaluate the application of the problematization methodology(PM) (Arch Maguerez), as an alternative teaching-learning method in formation post-graduation students. <strong>Material and Methods</strong>: 25 post-graduate students of  the program in Restorative Dentistry at the  School of Dentistry of ICT-Office of Science and Technology of São José dos Campos, São Paulo State University – UNESP, who were part of the discipline of Applied Teaching Higher Education , developed activities that characterized the problematization methodology (PM) and the traditional teaching methodology in force. By means of a questionnaire it was possible to assess the perception the students had of the activities made. <strong>Results</strong>: It was observed that problematization methodology (PM) was a valid alternative teaching-learning method for formation of new professors, in the opinion of students. <strong>Conclusion</strong>: problematization methodology (PM) can be applied as a complementary tool in the construction of the future professors’ knowledge, in addition to being a strategy for research and study. </p>

The aim of this study was to investigate the effect of bleaching treatment with 10% carbamide peroxide in white spot lesionsaffected teeth treated with caries infiltration technique. Cylindrical enamel-dentin specimens were prepared from bovine incisors. Baseline color measurement was performed by a spectrophotometer using the CIE L*a*b* system and specimens were divided in two groups: Sound (S) and demineralized (D) enamel. The group S was divided into two subgroups (n = 20): Nonbleached (SNB) and bleached (SB). The group D was divided in four subgroups (n = 20): Nonbleached (DNB), bleached (DB), resin infiltrated/nonbleached (DRNB) and resin infiltrated/ bleached (DRB). Artificial white spot lesions were produced in all groups D, simulating the presence of active lesions in labial tooth surface, and after demineralization, caries infiltration with low viscosity resin was performed in the resin infiltrated groups. In the bleached groups, 10% carbamide peroxide gel was applied (2 hours/day for 14 days). New color measurements were performed after bleaching and color alteration was calculated using E parameter. Data were submitted to oneway ANOVA and Tukey test (5%). There were significant differences among groups when E was evaluated (p = 0.001). Means (± standard deviation) and results of Tukey test were: SNB (2.53 ± 0.48)a; DRNB (2.88 ± 1.03)ab; DNB (3.15 ± 0.65) ab; DRB (2.88 ± 1.03)bc; SB (4.33 ± 0.93)cd; DB (5.27 ± 1.33)d. The bleaching treatment with 10% carbamide peroxide produced no significant color alteration in demineralized enamel treated with resin infiltration technique.