No abstract

Objectives: To measure the micro-tensile bond strength (μTBS) of a new universal adhesive (UA) bonded to dentin following a quick bonding mode. Materials and Methods:The experimental UA 'SKB-100', now commercialized as Clearfil Universal Bond Quick ('C-UBq'; Kuraray Noritake), was investigated, with Scotchbond Universal ('SBU'; 3M Oral care) and the 2-step self-etch (SE) adhesive Clearfil SE Bond 2 ('C-SE2'; Kuraray Noritake) serving as references. The adhesives were employed separately in etch&rinse (E&R) and SE mode on each tooth half following a split-tooth design and following their respective instructions for use, except for C-UBq that besides the manufacturer's instructed quick bonding mode was also applied and left untouched for 20 s prior to light-curing ('C-UBq_20s') and for C-SE2 that was also applied in E&R mode. μTBS of half of the specimens was measured upon 1-week (1w), with the other half tested after 6-month (6m) storage in distilled water at 37°C. Data were statistically analyzed using linear mixed-effects modeling and 3-way ANOVA (p<.05). The adhesive-dentin interfaces were ultra-structurally characterized by TEM.Results: C-UBq revealed a significantly lower μTBS than C-SE2. The highest μTBS was recorded for C-UBq_20s_1w and C-SE2_1w, both when applied in E&R mode. However, μTBS of C-UBq_20s significantly decreased upon aging in both modes. C-SE2 presented the significantly highest 'aged' μTBS. Conclusion:C-UBq applied in the quick bonding mode did not underperform to the UAs applied for 20 s. Superior bonding effectiveness was achieved by C-SE2 in SE and E&R bonding modes. Clinical relevance:Extended application time of C-UBq improved solely its immediate but not aged bonding effectiveness.