Estudo in vitro das alteraçöes morfológicas da dentina humana irradiada com o laser de Er: Yag e sua relaçäo com dois diferentes sistemas adesivos dentinários / A morphologica in vitro study of the human dentin irradiated by Er: Yag laser and the relationship between two different adhesive systems

The aim of this in vitro study was to evaluated the influence of Er: YAG laser on tensile bond strengh of two adhesive systems (Single Bond and Clearfil Liner Bond SE) on dentin surface, and scanning electron microscope analysis of the interface irradiated with the same laser. Transmission electron microscope analysis was used on dentin. For these purpose, 92 extracted human molars were sectioned longitudinally in bucallingual direction. The oclusal surface were grounded and polished. Thes specimens were divided into 5 groups and subdivided in A and B (Single Bond with and whitout acid) and A, B, C, D (Clearfil Liner Bond SE). The energy used were 250 mJ e 2Hz; 250 mJ e 2 Hz + 60 mJ e 10 Hz; a 400 mJ a 10 Hz. Statistical analysis showed on dentin that tensile bond strength values were better in the group with acid etching. Analysis by SEM showed that the Er: YAG laser ablated the dentin, opened the tubules. Analysis by TEM showed a deproteination of collagen. This in vitro results prove that the Erl?YAG laser had a n effect on dentin an the use of the acid etching is necessary for the adhesion process

Avaliaçäo da evoluçäo e utilizaçäo dos materiais de moldagem no Brasil / Evaluation of the evolution of impression materials utilized in Brazil

Neste estudo houve a preocupaçäo de se saber, em termos percentuais, quais os materiais de moldagem que estäo sendo utilizados pelo cirurgiäo-dentista brasileiro, quando do processo de confecçäo de prótese fixas. A evoluçäo dos materiais de moldagem processada na última década também foi notada na análise deste trabalho