Dentin Cross-linking Effect of Carbodiimide After 5 Years

• DOI: 10.1177/00220345211014799
• Publication Date: 2021-05-19T15:38:52Z
• Authors: T. Maravic; E. Mancuso; A. Comba; V. Checchi; L. Generali; C. Mazzitelli; U. Josic; V. Hass; A. Reis; A.D. Loguercio; F.R. Tay; L. Breschi; A. Mazzoni
• Keywords: carbodiimides; dental bonding; dentin; fibrillar collagen; hydrolysis; matrix metalloproteinases; Carbodiimides; 03 medical and health sciences; 0302 clinical medicine; Dentin-Bonding Agents; Tensile Strength; Dentin; Materials Testing; carbodiimides; dental bonding; dentin; fibrillar collagen; hydrolysis; matrix metalloproteinases; Composite Resins; Dentin; Dentin-Bonding Agents; Humans; Materials Testing; Resin Cements; Tensile Strength; Carbodiimides; Dental Bonding; Dental Bonding; Humans; Composite Resins; Resin Cements

Carbodiimide (EDC)–based dentin primers preserve hybrid layer (HL) integrity. However, aging >1 y has not been investigated. The present study examined whether the cross-linking effect of EDC was reflected in dentin bond strength, endogenous enzymatic activity, and the chemical profile of the HL after 5-y aging in artificial saliva. Noncarious human third molars ( N = 42) were cut to expose middle/deep coronal dentin and treated as follows: group 1, dentin etched with 35% H3PO4, pretreated with a 0.3M aqueous EDC primer for 1 min and restored with XP Bond (Dentsply Sirona); group 2, as in group 1 but without EDC pretreatment; group 3, Clearfil SE Bond (Kuraray-Noritake) primer applied to dentin surface, followed by EDC pretreatment as in group 1 and application of bond; group 4, as in group 3 without EDC pretreatment. After composite buildup, the specimens were cut into sticks or slabs, depending on the experiment. All tests were performed at baseline (T0) and after 5 y of aging (T5) in artificial saliva at 37 °C. Microtensile bond strength (µTBS) was tested at a crosshead speed of 1 mm/min until failure. Endogenous enzymatic activity was investigated with in situ zymography. The chemical profile of HL was determined via Raman spectroscopy. Three-way analysis of variance and post hoc Tukey test were used to analyze µTBS and in situ zymography data (α = 0.05). EDC pretreatment and aging significantly influenced µTBS and in situ zymography results ( P < 0.05). Higher bond strength and lower gelatinolytic activity were identified in the EDC-treated groups at T5 ( P < 0.05), especially in the etch-and-rinse groups. Raman spectra revealed less defined amide III peaks in control specimens at T5. The EDC cross-linking effect persisted in the HL for 5 y in terms of bond strength, collagen structure preservation, and dentinal enzyme silencing.