Effects of Laser Treatment on the Bond Strength of Differently Sintered Zirconia Ceramics.
OBJECTIVE
The purpose of this study was to investigate the effects of carbon dioxide (CO2) and Erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiations on the shear bond strength (SBS) of differently sintered zirconia ceramics to resin cement.


METHODS
Eighty zirconia specimens were prepared, sintered in two different periods (short = Ss, long = Ls), and divided into four treatment groups (n = 10 each). These groups were (a) untreated (control), (b) Er:YAG laser irradiated with 6 W power for 5 sec, (c) CO2 laser with 2 W power for 10 sec, (d) CO2 laser with 4 W power for 10 sec. Scanning electron microscope (SEM) images were recorded for each of the eight groups. Eighty composite resin discs (3 × 3 mm) were fabricated and cemented with an adhesive resin cement to ceramic specimens. The SBS test was performed after specimens were stored in water for 24 h by an universal testing machine at a crosshead speed of 1 mm/min. Data were statistically analyzed with two way analysis of variance (ANOVA) and Tukey honest significant difference (HSD) test (α = 0.05).


RESULTS
According to the ANOVA, the sintering time, surface treatments and their interaction were statistically significant (p < 0.05). Although each of the laser-irradiated groups were significantly higher than the control groups, there was no statistically significant difference among them (p > 0.05).


CONCLUSIONS
Variation in sintering time from 2.5 to 5.0 h may have influenced the SBS of Yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics. Although CO2 and Er:YAG laser irradiation techniques may increase the SBS values of both tested zirconia ceramics, they are recommended for clinicians as an alternative pretreatment method.
1 Department of Prosthodontics, Faculty of Dentistry, Ordu University , Ordu, Turkey .
Doğu Ömür
DÖ
Dede
2 Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayıs University , Samsun, Turkey .
Murat
M
Yenisey
3 Health Ministry Oral-Teeth Health Center , Bafra, Samsun, Turkey .
Nergiz
N
Rona
4 Department of Periodontics, Faculty of Dentistry, Ordu University , Ordu, Turkey .
Figen
F
Öngöz Dede
D002516:Ceramics / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D054020:Lasers, Gas; D053844:Lasers, Solid-State; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry*
D003764:Dental Materials; D019279:Resin Cements; D015040:Zirconium; C028541:zirconium oxide