10-Methacryloyloxydecyl Dihydrogen Phosphate (10-MDP)-Containing Cleaner Improves Bond Strength to Contaminated Monolithic Zirconia: An In-Vitro Study

Effect of Dentin Contamination with Hemostatic Agents and Cleaning Techniques on Bonding with Self-Adhesive Resin Cement

BACKGROUND Dentin contamination with hemostatic agents before bonding indirect restorations negatively affects the bond strength. However, the consensus on which materials could be used to clean contamination of hemostatic agents has not been explored. The aim of this study was to assess the effect of Katana Cleaner applied on the surface of dentin contaminated with hemostatic agents on the shear bond strength (SBS) of self-adhesive resin cement by comparing it with three other surface cleaners. MATERIAL AND METHODS Ninety dentin specimens were divided into a no contamination group (control) (n=10), 4 groups contaminated with 25% aluminum chloride (Viscostat Clear) (n=40), and 4 groups contaminated with 20% ferric sulfate (Viscostat) (n=40). Subsequently, 4 different cleaners were used for each contamination group (water rinse, phosphoric acid, chlorhexidine, and Katana Cleaner). Then, self-adhesive resin cement was directly bonded to the treated surfaces. All specimens were subjected to 5000 thermal cycles of artificial aging. The shear bond strength was measured using a universal testing machine. RESULTS Two-way analysis of variance showed that the contaminant type as the main factor was statistically non-significant (p=0.655), cleaner type as the main factor was highly significant (p<0.001), and interaction between the contaminant and cleaner was non-significant (p=0.51). The cleaner type was the main factor influencing the bond strength. Phosphoric acid and chlorhexidine showed better performance than Katana Cleaner. CONCLUSIONS Cleaning dentin surface contamination with phosphoric acid and chlorhexidine had better performance than with Katana Cleaner.

Bonding Effectiveness of Saliva-Contaminated Monolithic Zirconia Ceramics Using Different Decontamination Protocols

Objective

This research study investigated the effect of new decontamination protocols on the bonding capacity of saliva-contaminated monolithic zirconia (MZ) ceramics cemented with two different monomer-containing self-adhesive resin cements.

Materials and Methods

Standardized tooth preparations (4 mm. axial height) were performed for eighty human maxillary premolars under constant water cooling system. Eighty monolithic zirconia crowns (Whitepeaks Supreme Monolith) (n = 8/10 groups) were manufactured by CAD-CAM. Specimens were kept in the artificial saliva at pH = 7.3 for 1 minute at 37°C except control groups. The specimens have not been prealumina blasted and grouped according to cleaning methods and resin cements: control groups (C) (no saliva contamination + GPDM + 4-META (N) (CN) and 10-MDP (M) containing resin cement (CM), alumina blasted (AL) + GPDM + 4-META (ALN) and 10-MDP containing resin cement (ALM), zirconium oxide containing universal cleaning agent (IC) applied + GPDM + 4-META (N) (ICN) and 10-MDP containing resin cement (ICM), pumice (P) applied + GPDM + 4-META (PN) and 10-MDP containing resin cement (PM), and air-water spray (AW) applied + GPDM + 4-META (AWN) and 10-MDP containing resin cement (AWM)). Monobond Plus was applied to all surfaces for 40 seconds before cementation. The thermal cycle was applied at 5,000 cycles after cementation. The crowns were tested in tensile mode at a speed of 1 mm/min. The mode of failure was recorded. SEM examinations were carried out at different magnifications. Data were analyzed using rank-based Kruskal-Wallis and Mann-Whitney tests.

Results

No significant differences were found between the surface treatments and between the two types of resin cements. Interaction effects between surface treatments and resin cements were found to be significant by two-way ANOVA analysis. ICM group resulted in significantly better bond strength results compared with CN. ICM was found to result in better bond strength results compared with PM. The combination of universal cleaning agent and 10-MDP containing resin cement had significantly the highest cementation bond strength values. The increasing order of mean tensile bond strength values of decontamination protocols was C < AW < P < AL < IC. The mean tensile bond strength of 10-MDP containing resin cement was slightly higher than GPDM + 4-META containing resin cement.

Conclusions

Universal cleaning agents can be preferred as an efficient cleaning method with 10-MDP-containing cement after saliva contamination for better adhesive bond strength of 4 mm crown preparation height of monolithic zirconia ceramics.

Zirconia bond strength durability following artificial aging: A systematic review and meta-analysis of in vitro studies

The present study systematically reviewed the literature regarding the bond strength durability of zirconia ceramics to resin-based luting cements after application of different bonding protocols and aging conditions. Electronic searches in PubMed, Scopus, and Web of Science databases were performed for relevant literature published between January 1st 2015 and November 15th 2022. Ninety-three (93) English language in-vitro studies were included. The percentage of the mean bond strength change was recorded prior to and after artificial aging, and the weighted mean values and 95% confidence intervals were calculated. Bonding protocols were classified based on the combination of MDP/non-MDP containing cement/primer and surface pretreatment, as well as the level of artificial aging performed. Alumina sandblasting (SA) was identified as the most frequently used surface pre-treatment while an insufficient number of studies was identified for each category of alternative surface treatments. The combination of MDP cement with tribochemical silica coating (TSC) or SA yielded more durable results after aging, while the application of SA and TSC improved bond durability when a non-MDP cement and a non-MDP primer were used. TSC may lead to increased bond durability compared to SA, whereas MDP cements may act similarly when combined with SA or TSC.

Cleaning methods of contaminated zirconia: A systematic review and meta-analysis

OBJECTIVES

The aims of this study were to systematically review the literature and statistically analyze the effectiveness of different cleaning methods on the bond strength of resin cement to zirconia in short- and long-term aging conditions.

DATA/SOURCES

The literature was electronically searched in PubMed (MEDLINE), EMBASE, Wiley, Scopus, and Open Access Theses and Dissertations databases to select relevant articles that evaluated the bond strength between contaminated zirconia and resin cements. A manual search was performed by scanning the reference lists of included studies.

STUDY SELECTION

All articles were published online before April 2022 and in English. Meta-analyses were conducted using random effects models to calculate standardized mean differences (SMD) between uncontaminated zirconia and various cleaning methods in two aging conditions (short- and long-term). Statistical heterogeneity was assessed using I-square statistics. The risk of bias of all included studies was assessed. All statistical analyses were conducted using STATA (StataCorp, College Station, Texas).

RESULTS

Of the 1181 studies, 25 studies met the inclusion criteria for qualitative analyses. In short-term aging condition, cleaning contaminated zirconia with water, alcohol, or acid etching reported significantly lower bond strength than uncontaminated zirconia. For long-term aging condition, cleaning contaminated zirconia with water, cleaning agents, alcohol, or acid etching reported significantly lower bond strength than uncontaminated zirconia. Alumina air-abrasion or cleaning with sodium hypochlorite were comparable to uncontaminated zirconia for both short- and long-term aging conditions.

CONCLUSIONS

This meta-analysis appeared to indicate that the cleaning methods of contaminated zirconia restoration have an effect on zirconia bonding.

The effects of applying a novel cleaner on the bonding strength of zirconia surfaces

This study evaluates how pre-treatment with an MDP-containing cleaning agent (Katana Cleaner, Kuraray) influences the micro-shear bond strength (µSBS) of saliva-contaminated zirconia when used with universal adhesive (UA) systems. Rectangular specimens (2 mm × 12 mm × 15 mm) were obtained (IPS, e.max ZirCAD, MO, B65L17, Ivoclar Vivadent) and divided into three groups; a non-contaminated group (control group)(CON), a contaminated and cleaned with isopropyl alcohol group(ISP), and lastly, a group contaminated and cleaned with an MDP-containing cleaning agent(KAC). Each group was then subdivided into three subgroups according to the UAs used (n = 12). Composite cylinders were prepared and bonded to each surface with Panavia V5 (Kuraray, Noritake Dental). A µSBS test was performed and the data were evaluated with the two-way analysis of variance (two-way ANOVA) and multiple comparisons test (α = 0.05). The highest µSBS values were obtained in the non-contaminated group (p < 0.001), regardless of UAs. All subgroups showed lower µSBS values after saliva contamination, but KAC resulted in significantly higher µSBS values than 99% isopropanol (p < 0.001). Overall, the lowest µSBS value was obtained with 99% isopropanol. The KAC-Clearfil UA subgroup resulted in statistically significantly higher µSBS values than the other UAs (p = 0.035 and 0.007), although all three UAs resulted in sufficient µSBS values. This study revealed that applying KAC followed by a UA containing phosphate monomers produces promising results for improving µSBS values of zirconia, greater than results using 99% isopropanol.Clinical relevance: An MDP-containing cleaning agent followed by a phosphate monomer containing a universal adhesive is a promising method to obtain acceptable bonds with saliva-contaminated zirconia ceramics.

Effect of Different Cleaning Methods on Shear Bond Strength of Resin Cement to Contaminated Zirconia

The aim of this study was to evaluate the effect of different cleaning methods on the shear bond strength (SBS) of resin cement to contaminated zirconia specimens. Eighty rectangular-shaped specimens (2 × 5 × 10 mm) were fabricated from Zirconia blocks (IPS e.max ZirCAD) and randomly divided into 8 groups (n = 10). Group A (control) was not exposed to contaminants. The following tests specimens were contaminated with saliva and silicone indicating paste. Group B was coated with ceramic primer, then subjected to contamination. Groups C, D, E, F, G, and H were contaminated; cleaned with water rinse, Ivoclean, air particle abrasion, hydrofluoric acid, KATANA^TM Cleaner and ZirClean^TM, respectively, and then coated with ceramic primer and bonded to dual cure resin cement cylinders. All the specimens were subjected to artificial aging and surviving specimens were subjected to the SBS test. For statistical analysis, ANOVA and multiple comparison methods at the 0.05 significance level were used. There was no statistically significant difference among Ivoclean (21.48 ± 2.90 MPa), air particle abrasion (21.92 ± 2.85 MPa), and the control group (24.68 ± 5.46). The application of ceramic primer before contamination did not preserve the SBS of resin cement to zirconia. Cleaning the contaminated zirconia surface with hydrofluoric acid (15.03 ± 3.63) or KATANA^TM Cleaner (17.27 ± 7.63) did not restore SBS to the uncontaminated state, but it was significantly higher than simply rinsing with water (12.46 ± 5.17) or the use of ZirClean^TM (11.59 ± 5.53). The bond strength of resin cement to zirconia was influenced by cleaning methods.