Effects of Three Novel Bracket Luting Agents Containing Zirconia Primer on Shear Bond Strength of Metal Orthodontic Brackets Attached to Monolithic Zirconia Crowns: A Preliminary In Vitro Study.

Milad Shamohammadi Heidari,Hamed Tabatabaei,Mehrnaz Moradinejad,Vahid Rakhshan,Dinesh Rokaya

doi:10.1155/2022/7107526

Abstract

Background The increased use of zirconia crowns in adult orthodontic patients warrants the establishment of methods and materials to adhere orthodontic brackets properly to zirconia crowns. However, studies in this regard are scarce, and many materials remain untested. This preliminary study aimed to examine three new adhesives containing zirconia primers for the first time. Methods Sixty identical monolithic zirconia crowns were fabricated and randomly divided into 4 groups of 15 each (Panavia SA Cement Plus, G-CEM, TheraCem, and Transbond XT Composite (control)). After glaze removal with a diamond bur, a metal orthodontic bracket was attached to the surfaces of the crowns using the respective adhesive. Specimens were incubated at 37°C and then thermocycled for 2000 cycles. Shear bond strengths (SBS) of brackets in different groups were estimated using a universal testing machine. Mean SBS values were compared with the values 6, 8, and 10 (as acceptable SBS values) and 13 MPa (as the maximum SBS tolerable by zirconia) using the one-sample t-test. They were also compared with each other using the one-way ANOVA and Tamhane post hoc test (α = 0.05). Results The ANOVA indicated a significant overall difference; the Tamhane test showed that the difference between the control group and all test groups was significant (P < 0.0005); however, the 3 test groups were not significantly different from each other (P > 0.30). The SBS of the control group was significantly lower than the minimum acceptable SBS (6 MPa, P < 0.0005). The mean SBS of the TheraCem was not significantly different from 10 MPa (P = 0.902), while the mean SBS values of Panavia SA Cement Plus and G-CEM were significantly greater than 10 MPa (P < 0.05). None of the three zirconia adhesives had mean SBS values higher than 13 MPa. Conclusion All novel zirconia adhesives (Panavia SA Cement Plus, G-CEM, and TheraCem) generated SBS values adequate to attach metal orthodontic brackets to zirconia prostheses (at or greater than 10 MPa) without damaging the zirconia during bracket removal (not above 13 MPa).

Highlights

Esthetics is an ever-increasing demand of dental patients, especially adult ones; the number of adults who have esthetic dental restorations and seek orthodontic treatment is increasing [1, 2]
In terms of resin cement used, the samples were randomly divided into four groups: Group 1: Panavia SA Cement Plus (Kuraray, Okayama, Japan); Group 2: G-CEM (GC); Group 3: eraCem (Bisco, Schaumburg, Illinois, USA); Group 4: Transbond XT Composite (3M UniTek, Monrovia, USA). e sample size was predetermined as 15 specimens per group by augmenting the sample sizes of previous studies [4]
Results e control group showed the lowest mean Shear bond strengths (SBS), while Panavia and G-CEM had the highest mean SBS values (Table 1, Figure 2). e one-way analysis of variance (ANOVA) showed that there was a significant difference among the 4 groups (P < 0.0000005). e Tamhane post hoc test showed that the mean SBS of the control group was significantly lower than

Summary

Introduction

Esthetics is an ever-increasing demand of dental patients, especially adult ones; the number of adults who have esthetic dental restorations and seek orthodontic treatment is increasing [1, 2]. It cannot be etched, even using hydrofluoric acid, and does not provide proper bracket bonds [3, 4, 13]. In restorative dentistry and prosthodontics, different studies have tested methods and materials to increase the zirconia bond, including surface treatments using alumina or silica [12, 14,15,16] and zirconia primers [4, 12, 17,18,19], which usually contain 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP), the phosphate group of which reacts chemically with zirconium oxide, increasing the bond strength [4]. This study aimed to investigate the SBS of brackets bonded to monolithic zirconia crowns using three other primers. This study aimed to investigate the SBS of brackets bonded to monolithic zirconia crowns using three other primers. e null hypothesis was the lack of any difference among the shear bond strengths of the four groups

Materials and Methods

Findings

Conclusions