Comparison of Shear Bond Strength of Orthodontic Brackets Using Direct and Indirect Bonding Methods in Vitro and in Vivo

Abstract

Aim:Aim of article was to compare the shear bond strength of indirectly and directly bonded orthodontic brackets.Materials and methods:The experimental in vitro study included 60 maxillary and mandibular premolars. Teeth were mounted on cold-cure acrylic blocks for each tooth separately and divided into two groups: directly bonded brackets (30 teeth) and indirectly bonded brackets (30 teeth). Brackets (Discovery, Roth 0.022”, Dentaurum, Ispringen, Germany) were bonded using Transbond XT (3M Unitek, Monrovia, CA, USA) in direct method, while in indirect technique, a combination of Transbond XT and Sondhi Rapid Set (3M Unitek, Monrovia, CA, USA) was used. The shear bond strength and adhesive remnant index (ARI) were evaluated. The in vivo study included 30 subjects - 15 with indirectly bonded brackets and 15 with directly bonded brackets. Survival rate was assessed during the period of 6 months.Results:No statistically significant difference in the shear bond strength was found in direct (7.48±1.61 MPa) and indirect labial bonding methods (7.8.2±1.61 MPa). Both methods produced very similar amount of adhesive remnant on tooth surface (median = 1; interquartile range 1–2). There were no significant differences in bracket survival rate between methods.Conclusion:Regarding the shear bond strength, adhesive remnant on tooth surface, and survival rate, both indirect and direct methods of orthodontic bracket bonding seem to be equally valuable methods in clinical practice.

Effectiveness, efficiency and adverse effects of using direct or indirect bonding technique in orthodontic patients: a systematic review and meta-analysis

“…No significant difference of bond failure rate was found between the direct and indirect bonding in the meta-analysis. This finding corroborated the idea of the in vivo part of a recent research [40] indicating that average survival rate for directly bonded brackets and indirectly bonded brackets was 98.6 and 98.3%, respectively, without significant difference. During the indirect bonding, it was often practically difficult to place a tray for multiple teeth correctly with a uniform and steady pressure on each tooth [41], which might result in uneven/excessive adhesives or low bonding strength [2, 18, 42].…”

Indirect orthodontic bonding with drop-shaped hot glue tray: a simple and cost-effective technique

“…Authors have reported this system is very effective in tensile and shear bond strength and failure rate, when compared to other adhesives (Shimizu et al 2012). In addition, Transbond XT™ presents similar behavior when used in direct or indirect bonding techniques, being able of reaching the same clinical efficiency when the indirect bonding technique is performed properly (Menini et al 2014;Tessore et al 2017;Demirovic et al 2018;Sharma et al 2018). The custom base adapts so closely to the tooth that it is only necessary to use a thin film of primer between the custom base resin and the etched enamel.…”

“…The high costs involved in this process, however, still do not allow its routine use among most orthodontists. Despite the availability of these proposed variations, the indirect procedure is not yet the gold standard, probably because of numerous procedural variables that must be controlled to obtain successful indirect bonding (Demirovic et al 2018). It is supported by the extra expenses and duration of laboratory phase, and sensitivity of the multiphase technique.…”

The Indirect Bonding Technique in Orthodontics—A Narrative Literature Review

“…Results of SBS revealed no statistical and clinical differences between the values obtained in the direct and indirect techniques (Table 1) [3,5,[7][8][9]17]. Moreover, bonding failure rates, total chairside time and the number of visits were comparable [18]. However, when adhesive remnant index (ARI) was assessed in a different study, bonding failure in the indirect technique was most prevalent in the area between the bracket base and the tooth surface [16].…”

“…Results of SBS revealed no statistical and clinical differences between the values obtained in the direct and indirect techniques (Table 1) [3,5,[7][8][9]17]. Moreover, bonding failure rates, total chairside time and the number of visits were comparable [18]. However, when…”