ONLINE ONLY Loss of surface enamel after bracket debonding: An in-vivo and ex-vivo evaluation Huib Berghauser Pont, a Mutlu O ¨ zcan, b Bora Bagis, c and Yijin Ren d Groningen, The Netherlands, Z € urich, Switzerland, and Trabzon, Turkey Introduction: The objective of this study was to evaluate the surface enamel after bracket debonding and residual resin removal. Methods: Thirty patients (female, 20; male, 10; mean age, 18.4 years) who completed orthodontic treatment with fixed appliances (Twin Brackets, 3M Unitek, Monrovia, Calif) (n 5 525) were in- cluded. The amounts of adhesive left on the tooth surfaces and the bracket bases were evaluated with the adhesive remnant index (ARI). ARI tooth (n 5 498) was assessed on digital photographs by 2 operators. After resin removal and polishing, epoxy replicas were made from the maxillary anterior teeth (n 5 62), and enamel surfaces were scored again with the enamel surface index. Elemental analysis was performed on the debonded bracket bases by using energy dispersive x-ray spectrometry mean area scanning analysis. The percentages of calcium and silicon were summed up to 100%. Tooth damage was estimated based on the incidence of calcium from enamel in relation to silicon from adhesive (Ca%) and the correlation between the ARI bracket and Ca%. Results and Conclusions: While ARI tooth results showed score 3 as the most frequent (41%) (P \0.05), followed by scores 0, 1, and 2 (28.7%, 17.9%, and 12.4%, respectively), ARI bracket results showed score 0 more often (40.6%) than the other scores (P \0.05). Maxillary anterior teeth had significantly more scores of 3 (49%) than the other groups of teeth (10%-25%) (chi-square; P \0.001). There were no enamel surface index scores of 0, 3, or 4. No correlation between the enamel surface index and ARI tooth scores was found (Spearman rho 5 0.014, P 5 0.91). The incidence of Ca% from the scanned brackets showed significant differences between the maxillary and mandibular teeth (14% 6 8.7% and 11.2% 6 6.5%, respectively; P \0.05), especially for the canines and second premolars (Kruskal-Wallis test, P \0.01). With more remnants on the bracket base, the Ca% was higher (Jonckheere Terpstra test, P \0.05). Iatrogenic damage to the enamel surface after bracket debonding was inevitable. Whether elemental loss from enamel has clinical significance is yet to be determined in a long-term clinical follow-up of the studied patient population. (Am J Orthod Dentofacial Orthop 2010;138:387.e1-387.e9) A fter orthodontic therapy with fixed appliances, from the clinical standpoint, a major concern is to avoid cohesive failures in the enamel during debonding brackets and at the same time to obtain tooth surfaces without adhesive. 1 Bonding onto and removal of brackets from the enamel surfaces are potential risks for topographic changes in the form of cracks, scarring, scratches, or loss of enamel. 2-7 The dilemma in adhesion of brackets in orthodontics is that it should be strong enough to prevent failure during all treatment but also low enough so that enamel damage would be none or minimal during bracket removal after treatment. Debonding forces can be influenced by many factors: type of enamel conditioning agents (phosphoric acid, self-etching primers, polyacrylic acid), 8 adhesive resin, cement, polymerization methods, bracket type, or bracket base architecture. 9,10 Usually, an increase in debonding force causes an increased risk of enamel damage. 11 Even though the dental literature contains many studies looking at these possible factors on bracket adhesion, their clinical significance remains scarce, since, in in-vitro studies, data are usually obtained with- out considering major intraoral factors—eg, saliva, masticatory forces, temperature, and pH changes. 12 Furthermore, clinical debonding with pliers creates a combination of shear, tensile, and torque forces. There- fore, 1 test method (shear or tensile) in vitro might not represent in-vivo debracketing techniques and, conse- quently, in-vivo bond strengths and failure types. 12 a Graduate student, Department of Orthodontics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. b Professor, Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, Univer- sity of Z€ urich, Z€ urich, Switzerland. c Assistant professor, Department of Prosthodontics, Faculty of Dentistry, Kara- deniz Technical University, Trabzon, Turkey. d Professor, Department of Orthodontics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. The authors report no commercial, proprietary, or financial interest in the prod- ucts or companies described in the article. Reprint requests to: Mutlu O ¨ zcan, University of Z€ urich, Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prostho- dontics and Dental Materials Science, Plattenstrasse 11, CH-8032, Z€ urich, Switzerland; e-mail, mutluozcan@hotmail.com. Submitted, October 2009; revised and accepted, January 2010. 0889-5406/$36.00 Copyright Ó 2010 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.01.028 387.e1