Effect of mechanical and air-particle cleansing protocols of provisional cement on immediate dentin sealing layer and subsequent adhesion of resin composite cement

Abstract

Originally published at: Özcan, Mutlu; Lamperti, Sofia (2015). Effect of mechanical and air-particle cleansing protocols of provisional cement on immediate dentin sealing layer and subsequent adhesion of resin composite cement. Journal of Adhesion Science and Technology, 29(24) Zürich, 2 Abstract: Immediate dentin sealing (IDS) could avoid contamination of dentin from impression material and provisional cement but prior to final cementation of indirect restorations, removal of the provisional cement may damage the IDS. The objectives of this study were to investigate the effect of mechanical and air-particle cleansing protocols of provisional cement on IDS layer and subsequent adhesion of resin composite cement. The cuspal dentin surfaces of human third molars (N=18, n quadrant =72) were exposed by a low speed diamond saw under water cooling and conditioned with an adhesive system based on 3-step etch and rinse technique (OptiBond FL). Provisional cement (Freegenol) was applied on each specimen.They were then randomly divided into 6 subgroups where the provisional cement was removed either by 1)Air-borne particle abrasion with 50 µm Al 2 O 3 particles at 2 bar (AL2), 2) Air-borne particle abrasion with 50µm Al 2 O 3 particles at 3.5 bar (AL3.5), 3) Air-borne particle abrasion with 30 µm SiO 2 particles at 2 bar (SL2), 4) Air-borne particle abrasion with 30 µm SiO 2 particles at 3.5 bar (SL3.5), 5) Prophylaxy paste (Cleanic) (PP) or 6) Pumice-water slurry (PW) at 1500 rpm for 15 s. The dentin surface on each tooth was assigned to 4 quadrants and each quadrant received the cleansing methods in a clockwise sequence. The non-contaminated and non-cleansed teeth acted as the control (N=3, n quadrant =12) (C). Two separate teeth, contaminated and cleansed according to 6 cleansing protocols, were allocated for Scanning Electron Microscopy (SEM) analysis (x2000). The dentin surfaces in each quadrant received resin composite luting cement (Variolink II, Ivoclar Vivadent) incrementally in a polyethylene mould (diameter: 1 mm 2 ; height: 4 mm) and photo-polymerized. The specimens were stored in distilled water for 24 hours at 37ºC until the testing procedures and then shear force was applied to the adhesive interface until failure occurred in a Universal Testing Machine (0.5 mm/min). Microshear bond (µSBS) was calculated by dividing the maximum load (N) by the bonding surface area of the resin cement. Failure types were analyzed using optical microscope and SEM. Data (MPa) were analyzed using one-way ANOVA (α=0.05). Two-parameterWeibull distribution values including the Weibull modulus, scale (m) and shape ( 0 ), values were calculated.Mean µSBS results (MPa) showed significant difference between the experimental groups (P=0.011) and were in descending order as follows: C (8±2. dentin and the adhesive resin, which is a combination of adhesive and cohesive failure in the adhesive resin. Cohesive failure in the dentin was not observed in any of the groups. Weibull distribution presented lower shape ( 0 ) for C (3.9), AL2 (3...

Removal of temporary cements following an immediate dentin hybridization approach: a comparison of mechanical and chemical methods for substrate cleaning

“…Within CL Group, however, µSBS values were generally lower, probably highlighting a more difficult removal of particles of the resin-based, light-cured luting agent. values was found between the removal of temporary cements with a prophylaxis paste or with two different sandblasting regimens (2 or 3.5 bar pressure) [19]. Abo-Hamar et al also identified a comparable efficacy between cleanings with sandblasting and curettes [25].…”

“…On the other hand, it should be emphasized that a prolonged, overextended action of some surface treatments might also produce obscuration of dentinal tubule openings due to formation of additional smear layers, finally providing less reliable adhesion results [26]. That problem is also observed with other more aggressive mechanical methods involving finishing or tungsten carbide burs, that might impair precise fitting of indirect restorations [19]; for this reason, they are not suggested for surface cleanings, and where not included in the present study. One previous research have investigated the effect of mechanical treatments (i.e: polishing and air abrasion) on IDS layers [27]: as revealed by SEM analysis, the amount of hybridized layer that was removed with that cleaning methods was not uniform (11.94 +/-16.46 µm), and a great range of values was recorded (0 to 145 µm); however, in the majority of cases, a minimum thickness of adhesive layer was preserved.…”

“…One previous research have investigated the effect of mechanical treatments (i.e: polishing and air abrasion) on IDS layers [27]: as revealed by SEM analysis, the amount of hybridized layer that was removed with that cleaning methods was not uniform (11.94 +/-16.46 µm), and a great range of values was recorded (0 to 145 µm); however, in the majority of cases, a minimum thickness of adhesive layer was preserved. This fact could be particularly beneficial for subsequent adhesion, since development of covalent bonding between the adhesive resin (with its available free monomers) and the methacrylate groups of the resin luting cement is possible [19,28]. the adoption of different adhesive systems and temporary cement in one case [29], and of different treatments in the other [19], might explain the obtained differences.…”

“…This fact could be particularly beneficial for subsequent adhesion, since development of covalent bonding between the adhesive resin (with its available free monomers) and the methacrylate groups of the resin luting cement is possible [19,28]. the adoption of different adhesive systems and temporary cement in one case [29], and of different treatments in the other [19], might explain the obtained differences.…”

“…According to a study of Sailer et al, contamination of the sealed dentin substrate with a temporary, eugenol-free cement -subsequently removed with a prophylaxis paste -decreased bond strength values of a conventional resin luting agent with respect to the values obtained on sealed, not-contaminated dentin surface [18]. Ozcan et al proposed different cleansing protocols to manage sealed dentin subsequently contaminated by a provisional cement; no significant difference was found in bond values among tested treatments, but none of them was able to reproduce bond strengths similar to a not-contaminated, not-cleaned control group (freshly ground dentin) [19]. Some conditioning treatments (i.e: like a particle abrasion with calcium carbonate, as reported by Falkensammer 2014 et al) might also be contraindicated for the removal of temporary remnants and/or to reactivate the hybridized layer before final cementation [20].…”