The immediate bonding effectiveness of contemporary adhesives is quite favorable, regardless of the approach used. In the long term, the bonding effectiveness of some adhesives drops dramatically, whereas the bond strengths of other adhesives are more stable. This review examines the fundamental processes that cause the adhesion of biomaterials to enamel and dentin to degrade with time. Non-carious class V clinical trials remain the ultimate test method for the assessment of bonding effectiveness, but in addition to being high-cost, they are time- and labor-consuming, and they provide little information on the true cause of clinical failure. Therefore, several laboratory protocols were developed to predict bond durability. This paper critically appraises methodologies that focus on chemical degradation patterns of hydrolysis and elution of interface components, as well as mechanically oriented test set-ups, such as fatigue and fracture toughness measurements. A correlation of in vitro and in vivo data revealed that, currently, the most validated method to assess adhesion durability involves aging of micro-specimens of biomaterials bonded to either enamel or dentin. After about 3 months, all classes of adhesives exhibited mechanical and morphological evidence of degradation that resembles in vivo aging effects. A comparison of contemporary adhesives revealed that the three-step etch-and-rinse adhesives remain the 'gold standard' in terms of durability. Any kind of simplification in the clinical application procedure results in loss of bonding effectiveness. Only the two-step self-etch adhesives approach the gold standard and do have some additional clinical benefits.

http://www.endoexperience.com/documents/DeMunketalDurabiltyofadhesionJDR.pdf

A Critical Review of the Durability of Adhesion to Tooth Tissue: Methods and Results

Bonding to tooth tissue can be achieved through an "etch&rinse," "self-etch" or "glass-ionomer" approach. In this paper, the basic bonding mechanism to enamel and dentin of these three approaches is demonstrated by means of ultramorphological and chemical characterization of tooth-biomaterial interfacial interactions. Furthermore, bond-strength testing and measurement of marginal-sealing effectiveness (the two most commonly employed methodologies to determine "bonding effectiveness" in the laboratory) are evaluated upon their value and relevance in predicting clinical performance. A new dynamic methodology to test biomaterial-tooth bonds in a fatigue mode is introduced with a recently developed micro-rotary fatigue-testing device. Eventually, today's adhesives will be critically weighted upon their performance in diverse laboratory studies and clinical trials. Special attention has been given to the benefits/drawbacks of an etch&rinse versus a self-etch approach and the long-term performance of these adhesives. Correlating data gathered in the laboratory with clinical results clearly showed that laboratory research CAN predict clinical effectiveness. Although there is a tendency to simplify bonding procedures, the data presented confirm that conventional three-step etch&rinse adhesives still perform most favorably and are most reliable in the long-term. Nevertheless, a self-etch approach may have the best future perspective. Clinically, when adhesives no longer require an "etch&rinse" step, the application time, and probably more importantly, the technique-sensitivity are substantially reduced. Especially "mild," two-step self-etch adhesives that bond through a combined micromechanical and chemical interaction with tooth tissue closely approach conventional three-step systems in bonding performance.

Buonocore memorial lecture, adhesion to enamel and dentin: current status and future challenges

Systematic review of the chemical composition of contemporary dental adhesives

Dental adhesion review: Aging and stability of the bonded interface

http://webdelprofesor.ula.ve/odontologia/robertramirez/PDF/1.pdf

State of the art of self-etch adhesives

Influence or handling on the behavior of adhesive restorations

Purpose To validate the rationale of using a conventional light-cur﻿ing resin-based composite (RBC) to lute thick indirect restorations by measuring mini-interfacial fracture toughness (mini-iFT). Materials and methods Freshly exposed dentin of extracted third molars (n = 64) was immediately sealed with a thin layer of an experimental RBC ﻿with a 50 wt% or 75 wt% (IDS)﻿ filler load. ﻿Two- ﻿or 6-mm﻿-thick CAD/CAM composite block﻿s ﻿were luted onto IDS using either pre-heated light-cure or dual-cure luting RBC﻿, with the latter having served as control. Samples were cut into sticks, upon which a notch was prepared at the interface between IDS and luting RBC﻿, prior to being submitted to ﻿a 4-point bending ﻿test to determine mini-iFT. The results were analyzed using a mixed linear model (LME). Failure mode at the fractured interface was determined using scanning electron microscopy (SEM). Results LME revealed ﻿that mini-iFT was not significantly affected by the composite block thickness (p = 0.39)﻿, but by ﻿the luting RBC (p Conclusion This work provides the proof of concept that 2- and 6-mm﻿-thick indirect restorations can safely be adhesively luted with pre-heated conventional light-cure RBC under controlled light-irradiation conditions. This strategy even seems beneficial in terms of mini-iFT compared to using a dual-cure luting RBC. IDS with lower filler content also appeared more favo﻿rable.

Bart Van Meerbeek

Papers

Influence or handling on the behavior of adhesive restorations

Mini-iFT Confirms Superior Adhesive Luting Performance using Light-curing Restorative Composites.

Bonding effectiveness of one-step self-etch adhesives to enamel and dentin

Editorial: JAD's impact factor increased to 2.008!

Editorial: Rubber-dam - a blessing not only in the Covid-19 era.