2020 Volume 63 Issue 6 Pages 519-526
Objectives: The clinical failure of hybrid resin crowns fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) involves various factors. The aim of this study was to evaluate the effect of decontamination agents for saliva contamination on the bonding of CAD/CAM crowns.
Methods: CAD/CAM resin blocks (KATANA AVENCIA Block Universal, Kuraray Noritake Dental) were bonded to the dentin surface with and without artificial saliva contamination. A newly developed decontamination agent containing MDP (DC-200C, Kuraray Noritake Dental) and two commercially available decontamination agents (Ivoclean, Ivoclar Vivadent; Multi Etchant, YAMAKIN) were used in this study. Flat dentin surfaces were prepared and divided into eight groups. CAD/CAM resin blocks were bonded to the dentin surface using PANAVIA V5 (Kuraray Noritake Dental) as follows: 1) control group without saliva contamination on either resin block or dentin, 2) resin block with saliva contamination, 3) resin block with saliva contamination and Ivoclean decontamination, 4) resin block with saliva contamination and Multi Etchant decontamination, 5) resin block with saliva contamination and DC-200C decontamination, 6) dentin with saliva contamination, 7) dentin with saliva contamination and Multi Etchant decontamination, and 8) dentin with saliva contamination and DC-200C decontamination. After 24 hours, the samples were subjected to microtensile bond strength testing at the crosshead speed of 1.0 mm/min. A saliva protein staining test was performed by the pigment binding method to investigate the effect of removing saliva protein. The results were statistically analyzed at the significance level of p=0.05.
Results: The obtained bond strength values in MPa were as follows: 1) 35.74±4.81, 2) 16.75±4.79, 3) 26.49±4.21, 4) 23.94±2.64, 5) 33.50±6.38, 6) 21.58±5.73, 7) 30.65±2.92, and 8) 34.43±5.33. The saliva contamination on both the CAD/CAM resin block and dentin surface showed significantly lower values than the control group (p<0.05). All the decontamination agents could significantly restore the bond strength from the saliva contamination (p<0.05), and DC-200C showed no significant difference from the control (p>0.05). From the results of the saliva protein staining test, DC-200C showed higher removal effect of saliva protein for the CAD/CAM resin surface than the other materials due to the surface active effect of MDP salt.
Conclusion: The bond strength of the saliva-contaminated CAD/CAM hybrid resin block was restored to the same level as before the contamination by using a new decontamination material (DC-200C). It is suggested that DC-200C has a higher salivary protein removal effect than the other decontamination materials.
