Comparative assessment of hydrofluoric acid and sandblasting etching technique on porcelain crowns

Abstract

One of the challenges the orthodontist face is how to increase bond strength between the brackets and tooth, various ceramic restorations or porcelain crowns. Bond strength can be affected by bracket type and design of their base, bonding adhesive, or etching technique. Aim: To evaluate and compare the effects of sandblasting and hydrofluoric acid etching on shear bond strength (SBS) of metallic orthodontic brackets, bonded to porcelain crowns surfaces used for prosthetic restorations. Silane coupling agent was used as bond strength enhancer in both the cases. Methodology: Thirty porcelain maxillary central incisor crowns were used in the study. The crowns were divided randomly into two groups: Group H-the porcelain crowns were etched with 9% hydrofluoric acid followed by application of silane and the brackets were bonded with a composite adhesive, Group S the porcelain crowns were microetched with 50 microns Al2O3 particles followed by silane application and metal brackets were then bonded with the composite adhesive. All bonded crowns were stored in distilled water for 1 week at 37.8 0 C before debonding. Result: The mean Shear bond strength values were significantly higher (p=0.001) in Sandblasting group than 9% Hydrofluoric acid with the mean±SD values as 12.6493±1.15084 and 7.4540±.54742 respectively. However, all SBS values in the present study were above the optimal range for orthodontic bonding (6-8MPa), rendering them clinically acceptable.

Comparison of shear bond strength of metallic brackets bonded to ceramic surfaces utilizing different adhesive systems: An in vitro study

“…This is because SBS values between 5.9 and 7.8 MPa are proposed as clinically effective, allowing adequate adhesion of the bracket to the ceramic surface. [ 28 29 30 31 ] However, bond strengths exceeding 13 MPa may cause fractures on the ceramic surface during debonding of the bracket at the end of orthodontic treatment. [ 28 30 32 ] Six brackets in G6 were detached from the ceramic surface (brackets bonded to zirconia surfaces using the Transbond™ XT adhesive system) before the submission to the SBS test.…”

“…[ 28 29 30 31 ] However, bond strengths exceeding 13 MPa may cause fractures on the ceramic surface during debonding of the bracket at the end of orthodontic treatment. [ 28 30 32 ] Six brackets in G6 were detached from the ceramic surface (brackets bonded to zirconia surfaces using the Transbond™ XT adhesive system) before the submission to the SBS test. The SBS test confirmed that the mean SBS value for this group (2.51 MPa) was significantly lower than the proposed optimal mean SBS values (5.9–7.8 MPa).…”

“…Several authors have advocated that it is preferable for adhesion failure to occur at the bracket-adhesive interface or within the adhesive so that the resin residue on the ceramic surface can be removed safely with rotary instruments. [ 30 35 36 37 38 ] Similarly, the adhesive failure in G2 (feldspathic conditioned by Transbond™ XT), G3 (lithium disilicate treated by Assure® Plus All), and G5 (zirconia conditioned by Assure® Plus All) was designated as mixed-type failures for all the specimens, indicating a favorable failure mode. Contrarily, all the samples in G6 (zirconia conditioned with Transbond™ XT) had a score “0” ARI designated to adhesive-ceramic interface failure.…”

Effects of glazing or polishing on the color stability of different computer-aided design/manufacturing ceramic surfaces after orthodontic debonding: An in-vitro comparative study

“…However, applying 9.6% hydrofluoric acid etching with a silane coupling agent produces sufficient results on its own, thus minimizing the need for air abrasion. This application has become the gold standard (23)(24)(25)(26)(27).…”

Effect of Er,Cr:YSGG Laser Versus Acid Etching Surface Treatment on the Surface Roughness and Topography of Two Pressable Lithium Disilicate Ceramics. “In-Vitro Study”.

“…Ultradent® Porcelain Etch 9% buffered (Ultradent, South Jordan, USA) Hydrofluoric acid etchant was applied on the unglazed surface of the ceramic discs by a brush following the manufacturer's instruction then removed by air/ water spray then dried. [30][31][32][33] The laser surface treatment protocol was carried out using Er,Cr:YSGG laser (Waterlase iplus, BIOLASE, Inc. USA) of wavelength 2790 nm (power setting: 4.5 watt, repetitive rate of 50 Hz "pulse per second" and pulse duration "pulse length": 60 µs) [23], [24] with a sweeping motion directing the Waterlase Laser Tip MGG6-9 (BIOLASE, Inc. USA) 45 o angle to the unglazed ceramic surface at a distance of 2mm with 80% water and 60% air for 60 seconds.…”