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The influence of humidity level in the conversion degree and bond-strength of different adhesives systems

Grant number: 18/06850-0
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): July 01, 2018
Effective date (End): June 30, 2019
Field of knowledge:Health Sciences - Dentistry - Dental Clinics
Principal Investigator:Dimorvan Bordin
Grantee:Arles Naisa Amaral Silva
Home Institution: Universidade Universus Veritas Guarulhos (Univeritas UNG). Guarulhos , SP, Brazil


An over-wet dentin after the acid-etching procedure might impair the complete adhesive polymerization as well an over-dry dentin does not allow adequate adhesive infiltration. Then, a hydrolytic degradation of the hybrid layer leading to margin pigmentation, post-operative pain, and secondary caries. This study will evaluate the influence of different dentin humidity levels in the conversion degree and bond-strength of different adhesive systems. The adhesive conversion degree kinetic will be measured using a Fourier transform infrared spectroscopy (FTIR). Two adhesive systems will be tested: Single Bond (SB) (control) and Prime & Bond Active (P&B) (experimental) at 4 different humidity levels of adhesive and water proportions (1:0,5; 1:1, 1:2;) (experimental groups); the pure adhesive, no water, will be used as control. The water will be deposited at the sensor using a micro pipette. After, human teeth from the University of Guarulhos will be drilled (Class I) with a standardized-dimensions cavity. After the acid-etching procedure, the teeth will be randomized into 6 groups according to the adhesive systems (SB or P&B) at 3 different dentin humidity levels: Over-dry by air-spray (OD) (experimental); Humid (H)- dried using absorbent paper (control); Over-wet (OW)- a 4µl of water will be deposited onto the cavity's floor. The cavities will be restored using a dental composite; Twenty-four hours after the restorations, the teeth will be sectioned and tested to measure the bond strength using a universal testing-machine. Data will be shown as bond strength (MPa). The sample size will be calculated after pilot test and exploratory data analysis.