STATEMENT OF PROBLEM: Whether laser-welded (LW) @entity702 can resist the stress corrosion produced by the combination of @entity1388 ions and stress in the oral environment is unknown. PURPOSE: The purpose of this in  vitro study was to investigate the influence of stress corrosion on the mechanical properties of LW @entity702 . MATERIAL AND METHODS: Twenty-seven @entity702 bars (25*2 mm) with a circular cross-section were cut in half and laser-welded, while another 27 nonwelded (NW) bars were used as the control. Thirty bars were submitted to a flexural load of 480 N at 1 Hz and immersed in artificial saliva at pH 6 (S1) or in 1000 ppm @entity1388 -containing saliva at pH 6.0 (S2) or 2.0 (S3) at room temperature for up to 4000 cycles. After the stress corrosion simulation, the tensile strength and Vickers microhardness were determined (n=5). Twelve LW and NW bars were submitted to the corrosion immersion test media for 51 days (n=2) to determine polarization curves (n=2) in an artificial saliva media. The corroded surface was examined with @entity4653 ( @entity4653 ). RESULTS: The combination of @entity1388 and low pH significantly decreased the tensile strength of LW (P<.05). Stress corrosion did not affect the hardness of LW or NW (P>.05). NW bars immersed in S3 exhibited progressive surface dissolution, while LW bars spontaneously @entity174 at the welded area after 25 days of immersion in the same medium. @entity4653 images demonstrated pitting corrosion without the presence of cracks in both groups immersed in S3. CONCLUSIONS: Stress corrosion caused by acidic @entity1388 -containing saliva and flexural load cycling decreased the tensile strength and hardness of LW @entity702 bars.

Influence of stress corrosion on the mechanical properties of laser-welded XXXX .

@entity702 :: ('MESH:D014025', 'Chemical') :: ['titanium'] @entity1388 :: ('MESH:D005459', 'Chemical') :: ['fluoride'] @entity174 :: ('MESH:D050723', 'Disease') :: ['fractured'] @entity4653 :: ('MESH:D004401', 'Disease') :: ['SEM', 'scanning electron microscopy']
@entity702 :: (MESH:D014025,Chemical) :: ['titanium']
