"No-bottle" vs "multi-bottle" dentin adhesives--a microtensile bond strength and morphological study.
OBJECTIVE
To compare the adhesive capability of the new adhesive Prompt L-Pop (ESPE) with that of two total-etch adhesive systems-EBS Multi (ESPE) and Prime&Bond NT (Dentsply).


METHODS
Extracted human molars were bonded and prepared for microtensile dentin bond strength (microTBS) testing using Prompt L-Pop, EBS Multi, and Prime&Bond NT combined with Pertac II (composite) or Hytac Aplitip (compomer). Prompt L-Pop was applied using five different protocols: (1) as an "all-in-one" self-conditioning adhesive, as per manufacturer's instructions (LP); (2) as a self-etching primer combined with a separate bonding resin (LP/self-etch 2-step); (3) as a classical primer used upon etching dentin with phosphoric acid, followed by a bonding resin (LP/total-etch 3-step); (4) as a multi-application "all-in-one" self-conditioning adhesive (LP/multi-coat) to leave a visibly glossy dentin surface; and (5) as a filled adhesive, upon adding quartz fillers to its composition (LP/filled). After 24h of storage in water at 37 degrees C the microTBS were measured in an Instron machine. Corresponding interfaces of the same specimens were micromorphologically analyzed using SEM and TEM.


RESULTS
When used with a composite resin, LP/filled and LP/multi-coat resulted in significantly higher microTBS than LP. The addition of an extra adhesive bonding resin (LP/self-etch 2-step) had no effect on bond strength. The use of Prompt L-Pop as a primer of a fourth-generation adhesive (LP/total-etch 3-step) replacing the EBS Multi primer, resulted in lower bond strengths than those of the original EBS Multi. LP/multi-coat showed similar microTBS to Prime&Bond NT (P&BNT). When used with a compomer, LP exhibited higher bond strengths than when used with the resin composite and was as effective as the experimental groups LP/filled and LP/multi-coat and the control group P&BNT. The SEM evaluation showed an inconsistent hybrid layer for the LP specimens, whereas in both the LP/filled and LP/multi-coat specimens a hybrid layer was clearly evident. Under the TEM all groups displayed dentin hybridization with dissolved smear plugs in the specimens that had been conditioned with Prompt L-Pop without a separate etching step. In many tubules of specimens conditioned with LP (as per manufacturer's instructions), fillers of the resin composite were present within the dentinal tubules.


CONCLUSIONS
When combined with a resin composite, Prompt L-Pop resulted in statistically lower bond strengths when applied in one layer than when applied in multiple layers. Prompt L-Pop also resulted in higher bond strengths when used with a polyacid-modified composite resin than with a composite resin. When applied in multiple coats, Prompt L-Pop results in bond strengths that are not statistically different from those of Prime&Bond NT, a total-etch adhesive.
Frankenberger
R
R
Policlinic for Operative Dentistry and Periodontology, University of Erlangen-Nuremberg, Glueckstrasse 11, D-91054 Erlangen, Germany.
Perdigão
J
J
Rosa
B T
BT
Lopes
M
M
D000134:Acid Etching, Dental; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D020770:Compomers / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011791:Quartz / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D016369:Smear Layer; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D014867:Water
D020770:Compomers; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C113072:EBS adhesive system; D005899:Glass Ionomer Cements; D008689:Methacrylates; C088836:Pertac-Bond; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C103500:Prime & Bond; C408584:Prompt L-Pop; D019279:Resin Cements; C105429:hytac; D014867:Water; D011791:Quartz; D017438:Bisphenol A-Glycidyl Methacrylate