OCT evaluation of the internal adaptation of ceramic veneers depending on preparation design and ceramic thickness

摘要

Objectives. In-vitro evaluation of the influence of preparation design and thickness of ceramic veneers on the interfacial bond using optical coherence tomography (OCT).Methods. Sixty-four central incisors were randomly assigned to four preparation designs differing from no to complete dentine exposure (n = 16 each): non-prep (NP), minimal-invasive (MI, no dentine exposure), semi-invasive (SI, 50% dentine) and invasive (I, 100% dentine). Ceramic veneers (IPS InLine Veneer) of two thicknesses (0.2-0.5 mm (T1) and 0.5-1.2 mm (T2)) were etched, silanized, and adhesively luted (Optibond FL, Variolink Veneer). After water storage (37 degrees C, 21d), thermocycling (2000 cycles, 5 degrees-55 degrees C), and mechanical loading (2 + 1 million cycles, 50 + 100 N) specimens were imaged by spectral-domain OCT (Telesto II, Thorlabs). Adhesive defects at the ceramic-composite and tooth-composite interfaces were quantified on 35 equidistantly distributed OCT B-scans (length, %). Statistical differences were verified with Wilcoxon-/Mann-Whitney-U-test (alpha = 0.05).Results. Adhesive defects appeared in all groups at both interfaces, albeit to differing extents (0.1- 31.7%). NP and MI veneers showed no significant differences at the interfaces (p(i) 0.05). In groups, SI and I, significantly more adhesive defects appeared at the tooth-composite compared to the veneer-composite interface (p(i) = 0.039). The following preparation designs and veneer thicknesses showed differences (p(i) = 0.021): Veneer-composite: NP-T1 I-T1, MI-TI I-T1, I-T1 I-T2; Tooth-composite: NP-T1 SI-T1, NP-T1 I-T1, NP-T2 MI-T2, MI-T1 SI-T1, MI-T1 I-T1, SI-T1 I-T1, MI-T2 SI-T2, MI-T2 I-T2.Significance. The interface adhesion of ceramic veneers was influenced by the preparation design and the veneer thickness. A ceramic thickness of at least 0.5 mm and a preparation without exposing dentine is advantageous for the interfacial bond. (C) 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.