Efeito do tratamento dentinário com hipoclorito de sódio pós condicionamento ácido na resistência adesiva de restaurações em resina composta

Introduction: The development of squamous cell carcinoma of oral cavity (SCC) is a multifactorial process, where the cellular mutagenesis is determined by co-carcinogenetic agents like the human papillomavirus (HPV). Objective: the objective of this study is to identify the HPV in the SCC by means of polymerase chain reaction (PCR). Methods: twenty cases of SCC have been analyzed where the material used was extracted from specimens included in paraffin blocks of the Pathology Laboratory file of the São Vicente de Paulo Hospital of Passo Fundo/RS in the period of 2003 to 2007. They were all male cases and the 6th decade of life was the most prevalent. The lower lip was the region that comprises most of the defects and the histological grade "well-differentiated" from the World Health Organization was predominant. It has been detected the presence of HPV's DNA in four of the 20 cases of the SCC (20%). Conclusions: it can be assured that, by the fact of the HPV has been identified in a considerable percentage of cases of SCC, it can have influence on the genesis of the referred malignant neoplasia. So, more studies are necessary to define what is the possible role of HPV in the oral carcinogenesis. Este trabalho teve como objetivo avaliar a resistência adesiva de restaurações de resina composta, mediante a remoção ou não do colágeno dentinário. Para tanto, foram utilizados 24 dentes bovinos, embutidos em resina acrílica e desgastados até se obter um remanescente de 2mm de dentina. Delimitou-se a área da adesão em 3mm de diâmetro. As amostras foram divididas em 2 grupos: G1 (controle): foi aplicado o sistema adesivo autocondicionante Adper Prompt L-Pop (3M ESPE), seguindo as recomendações do fabricante, e procedida a restauração com a resina Z100 (3M) pela técnica incremental, em matriz metálica e sobre a área preparada; G2 (teste): realização de condicionamento com ácido fosfórico 37% por 15s, lavagem, secagem, aplicação de hipoclorito de sódio (NaOCl) 10% por 60s, lavagem, secagem, aplicação do sistema adesivo autocondicionante e realização da restauração, como descrito anteriormente. Os espécimes foram imersos em água destilada e mantidos em estufa bacteriológica a 37ºC por 7 dias, e então submetidos ao teste de cisalhamento em uma máquina de ensaio universal EMIC (velocidade de 0,5mm/min). Após análise estatística (ANOVA e teste T), os valores médios encontrados foram: G1=8,32±2,28 MPa e G2=5,76±2,48MPa (p

Minimal intervention in dentistry : which is the best approach for silorane composite restoration repairs?

This study aimed to evaluate surface treatments, adhesives and composites for repairing silorane based restorations. One hundred and twenty truncated cones (2 mm smaller diameter and 4 mm larger diameter) made of silorane composite were divided in 12 g

Avaliação in vitro da efetividade de associações de agentes clareadores na alteração da cor de dentes manchados por pigmentos sangüineos

O objetivo deste estudo foi avaliar in vitro a efetividade de três associações de materiais clareadores na técnica mediata de clareamento de dentes tratados endodonticamente. Foram utilizados 48 pré-molares humanos íntegros, pigmentados artificialmente com sangue humano. Após preparo biomecânico, os canais radiculares foram obturados e o tampão cervical foi confeccionado com 3mm de cimento de fosfato de zinco ao nível da junção amelo-cementária. Os dentes foram divididos em quatro grupos (n=12): C (controle, sem material clareador), A1 (perborato de sódio + água destilada), A2 (perborato de sódio + peróxido de carbamida a 10%) e A3 (perborato de sódio + peróxido de carbamida a 35%). Os materiais clareadores foram trocados aos sete e 14 dias. Concluiu-se que o perborato de sódio associado ao peróxido de carbamida (tanto a 10%, como a 35%) foi mais efetivo do que quando associado à água destilada.The aim of this study was to evaluate in vitro the effectiveness of three associations of bleaching agents on artificially stained pulpless teeth. Forty-eight recently extracted intact human premolars were stained by immersing them in human blood, and divided into four groups. All teeth were endodontically treated and 3mm of zinc phosphate cement was placed at the cementoenamel junction. The teeth were divided into one control group and three test groups (n=12): C) control group, without bleaching agent, A1) sodium perborate with water, A2) sodium perborate with 10% carbamide peroxide, A3) sodium perborate with 35% carbamide peroxide. On days 7 and 14, each pulp chamber was refilled with fresh bleaching paste. Color coordinates of CIELAB color system were measured and assessed with the aid of a dental spectrophotometer (EasyShade®, Vita). It was concluded that sodium perborate mixed with carbamide peroxide (10% or 35%) was more effective than mixed with water.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Additional chemical polymerization of dual resin cements: reality or a goal to be achieved?

Abstract Introduction This study serves as a warning to dentists and researchers that dual-cured resin cements may not polymerize completely under some prosthetic crowns. Objective The aim of this study was to analyse the polymerization degree of dual-cured resin cements under prosthetic barrier, by microhardness test. Material and method Three cements (Bistite II, RelyX ARC and Variolink II) were light-cured through different barriers, placed between the cement and the light source: G1: without barrier; G2: composite resin (Cesead); G3: Inceram alumina; G4: IPS Empress; G5: Inceram zirconia; G6: tooth fragment. Photopolymerization was carried out using a halogen light unit (650 mW/cm2); microhardness was evaluated using the Microhardness Tester FM 700, under a load of 50gf with a dwell time of 15s, at two evaluation times (30min and 24h). Result The results were submitted to ANOVA and Tukey tests (5%). Both Inceram alumina and Inceram zirconia ceramic barriers hindered polymerization. Bistite, followed by RelyX and Variolink, exhibited the highest microhardness values (p<0.05). As the highest values were obtained without a barrier, it was determined that the barrier, followed by the tooth, influenced microhardness. Both Empress and Cesead had the smallest microhardness values but with no statistically significant difference between them. Conclusion The barrier negatively affected the microhardness of dual-cured resin cements; evaluation time did not affect microhardness values for most of the conditions tested. There is a limited effect of the chemical activator on the polymerization of some dual-cured cements, and their performance is product specific

Dentin bond strength: influence of Er:YAG and Nd:YAG lasers

The aim of this study was to investigate the effects of Er:YAG and Nd:YAG lasers on the shear bond strength of composite resin to dentin. The coronal portion of 56 human molars was divided into three parts, and the dentin thickness was standardized at 2 mm. A 3-mm hole was marked in the center of each tooth with sealing tape paper. The specimens (n = 14) were then divided into four groups: (1) acid etching + Single Bond (SB) (control), (2) acid etching + SB + Nd:YAG laser irradiation (before adhesive curing), (3) thermal etching with the Er:YAG laser + SB, and (4) thermal etching with the Er:YAG laser + SB + Nd:YAG laser irradiation (before adhesive curing). A composite resin cylinder was built into the delimited area for conducting the shear bond strength test on the universal testing machine. The means ± standard deviations were: group 1, 17.05 ± 4.15 MPa; group 2, 16.90 ± 3.36 MPa; group 3, 12.12 ± 3.85 MPa; and group 4, 12.92 ± 2.73 MPa. Groups 1 and 2 presented significantly higher values than groups 3 and 4. It was concluded that conventional etching with 37% phosphoric acid yielded significantly higher bond strength values compared to thermal etching with the Er:YAG laser. The Nd:YAG laser did not significantly influence the bond strength