[Occluding effects of desensitizer containing NovaMin combined with fluor protector on dentinal tubules:an in vitro study].

Puppose: To observe the occlusion effect, acid resistance and abrasion resistance of desensitizer containing NovaMin combined with fluor protector on dentin tubules, in order to provide theoretical basis for clinical treatment of dentin hypersensitivity.

Methods: Thirty extracted intact and non-carious human premolars for orthodontic treatment were selected and made into 2 mm thick dentin slices. Each slice was cut into 4 parts to form 120 sensitive dentin models and randomly divided into 4 groups (n=30).

[Study on the microleakage between the composite resin and cavity wall after Er,Cr:YSGG laser preparation].

Purpose: To evaluate microleakage between the composite resin and cavity wall after Er,Cr:YSGG laser preparation.

Methods: Class V cavities were prepared in 30 sound extracted human premolars. The teeth were randomly divided into 3 groups (n=10).

[A study on acquired acid resistance of enamel and dentine irradiated by Er, Cr: YSGG laser in vitro].

Objective: To evaluate the acid resistance of enamel and dentin irradiated by Er, Cr: YSGG laser to artificial caries formation in vitro.

Methods: Enamel and dentin samples were irradiated with Er, Cr: YSGG laser at 6 W or 4 W for 6 second, respectively. Every sample was immersed in 3 ml of lactic demineralization solution at pH 4.