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U n i v e r s i t y J D e n t S c i e 2 0 1 5 ; N o . 1 , V o l . 3 University Journal of Dental Sciences DEBONDING IN ORTHODONTICS : A REVIEW Review Articles 1 Neelutpal Bora, 2Nabanita Baruah Lecturer, 2Reader, Department of Orthodontics and Dentofacial Orthopedics Regional Dental College, Gawhati. 1 Abstract: The objectives of debonding are to remove the attachment and all the adhesive resin from the tooth and restore the surface as closely as possible to its pretreatment condition without inducing iatrogenic damage. To obtain these objectives, a correct technique is of fundamental importance. Debonding may be unnecessarily time consuming and damaging to the enamel if performed with improper technique or carelessly. The present article gives us an overview of the best possible methods so as to have an ideally desired tooth structure after debonding. INTRODUCTION: An expectation of beautiful smiles at the end of orthodontic treatment is a primary concern to each patient, but is also equally concerned with appearance while undergoing treatment. Many attempts have been made by manufacturers to meet this demand. Characteristic of an ideal orthodontic appliance include good esthetics and optimum technical performance. Reports of enamel fracture and cracks during debonding has raised questions about the safety of various procedures used to remove these attachments,1-4 although the tensile strength of ceramic is greater than that of stainless steel, less energy is used to cause fracture of ceramic brackets compared with conventional stainless steel brackets.4 This phenomenon is related to fracture toughness or the ability of a material to resist fracture and ceramic brackets have substancially less fracture toughness when compared to stainless steel brackets.5,6The adhesion between the resin and bracket base has increased to a point where the most common site of bond failure during debonding has shifted from bracket base- adhesive interface to enamel adhesive interface which could increase the risk of enamel damage Key word s: Debonding, iatrogenic, adhesive resin. Source of support : Nil Conflict of Interest : None which is a less desirable.7-9 This shift has led to an increase in the incidence of bond failures within the enamel surface.10 Different techniques used for debonding: Manufacturers have developed various debonding techniques specially for ceramic brackets, including the use of debonding pliers and ligature cutting pliers to apply a squeezing force at the bracket base as well as the application of a shear torsion force with a specially designed instrument.6, 11 Alternate debonding techniques that minimize the potential for bracket failure as well as trauma to the enamel surface during debonding. Ultrasonic debracketing tips uses specially designed tips applied at the bracket adhesive junction.1,3, 57,12 Thermal debonding has also been suggested as a method for debonding ceramic brackets.9,13 Clinical Procedures Although several methods have been recommended in the literature for bracket removal and adhesive cleanup, and some discrepancy of opinion still exists. The clinical debonding procedure may be divided in two stages: U n i v e r s i t y J o u r n a l o f D e n t a l S c i e n c e s , A n O f f i c i a l P u b l i c a t i o n o f A l i g a r h M u s l i m U n i v e r s i t y , A l i g a r h . I n d i a 7 7 U n i v e r s i t y J D e n t S c i e 2 0 1 5 ; N o . 1 , V o l . 3 1. Bracket removal 2. Removal of residual adhesive Bracket removal: steel brackets (Fig.1) Several different procedures for debracketing with pliers are available. An original method was to place the tips of a twinbeaked pliers against the mesial and distal edges of the bonding base and cut the brackets off between the tooth and the base. Several pliers are available for this purpose. A gentler technique is to squeeze the bracket wings mesio distally and lift the bracket off with a peel force. This is particularly useful on brittle, mobile, or endodontically treated teeth. The brackets are deformed easily and are less suitable for recycling when the latter method is used. This is a recommended technique, in which brackets are not deformed. This technique uses a peeling-type force, which is most effective in breaking the adhesive bond. A peel force, as in peeling an orange, creates peripheral stress concentrations that cause bonded metal brackets to fail at low force values.11-12 The break is likely to occur in the adhesive bracket interface, thus leaving adhesive remnants on the enamel. Attempts to remove the bracket by shearing it off (as is done in removing bands) can be traumatic to the patient and potentially damaging to the enamel. fracture, which in practice requires grinding away the rest of the bracket. Cutting the brackets off with gradual pressure from the tips of twin-beaked pliers oriented mesiodistally close to the bracket-adhesive interface is not recommended because it might introduce horizontal enamel cracks. More recent ceramic brackets have a mechanical lock base and a vertical slot-that will split the bracket by squeezing.6-8 Separation is at the bracket-adhesive interface, with little risk of enamel fracture. Low-speed grinding of ceramic brackets with no water cool ant may cause permanent damage or necrosis of dental pulps. Therefore water cooling of the grinding sites is necessary. High-volume suction and eye protection also are recommended to reduce the number of ceramic particles spread about the operatory area. Finally, thermal debonding the use of lasers have the potential to be less traumatic and less risky for enamel damage, but these techniques are still at an introductory stage. Removal of residual adhesive After debonding of brackets evaluation of residual adhesive and sites of bond failure are recorded using Adhesive Remnant Index (ARI) . It is a four scale index to determine the amount of adhesive remnants on the enamel surface after debracketing and was introduced by Artun and Bergland. 14 Adhesive Remnant Index (ARI) Bracket removal: ceramic brackets (Fig.2) With the introduction of ceramic brackets, a new concern over enamel fracture and loss from debonding has arisen. Because of differences in bracket chemistry and bonding mechanisms, various ceramic brackets behave differently on debonding. For example, ceramic brackets using mechanical retention cause fewer problems in debonding than do those using chemical retention. In this regard, some knowledge about the normal frequency, distribution, and orientation of enamel cracks in young and in older teeth is important. Ceramic brackets will not flex when squeezed with debonding pliers. The preferred mechanical debonding is to lift the brackets off with peripheral force application, much the same as for steel brackets. Several tie-wings still may Score 0 – No adhesive left on the enamel. Score 1 – Less than half of the adhesive left on the enamel. Score 2 – More than half of the adhesive left on the enamel. Score 3 – All adhesive left on the tooth surface with distinct impression of the bracket mesh. Because of the color similarity between present adhesives and enamel, complete removal of all remaining adhesive is not achieved easily. Many patients may be left with incomplete resin removal, which is not acceptable. Abrasive wear of present bonding resins is limited, and remnants are likely to U n i v e r s i t y J o u r n a l o f D e n t a l S c i e n c e s , A n O f f i c i a l P u b l i c a t i o n o f A l i g a r h M u s l i m U n i v e r s i t y , A l i g a r h . I n d i a 7 8 U n i v e r s i t y J D e n t S c i e 2 0 1 5 ; N o . 1 , V o l . 3 become unesthetically discolored with time. The removal of excess adhesive may be accomplished by (1) scraping with a sharp band or bondremoving (2) using a suitable bur and contraangle .(Fig.3) Although the first method is fast and frequently successful on curved teeth (premolars, canines), it is less useful on flat anterior teeth. A risk also exists of creating significant scratch marks. The preferred alternative is to use a suitable dome tapered tungsten carbide bur (#1171 or #1172) in a contra angle handpiece. Clinical experience and laboratory studies indicate that about 30,000 rpm is optimal for rapid adhesive removal without enamel damage. Light painting movements of the bur should be used so as not to scratch the enamel. Water cooling should not be used when the last remnants are removed because water lessens the contrast with enamel. Speeds higher than 30,000 rpm using fine fluted tungsten carbide burs may be useful for bulk removal but are not indicated closer to the enamel because of the risk of marring the surface. Even ultra fine high-speed diamonds produce considerable surface scratches. Slower speeds (10,000 rpm and less) are ineffective, and the increased jiggling vibration of the bur may be uncomfortable to the patient. When all adhesive has been removed, the tooth surface may be polished with pumice (or a commercial prophylaxis paste) in a routine manner. CHARACTERISTICS OF NORMAL ENAMEL Apparently not every clinician is familiar with the dynamic changes that continuously take place throughout life in the outer, most superficial enamel layers. Because a tooth surface is not in a static state, the normal structure differs considerably between young, adolescent, and adult teeth. Normal wear must be considered in any discussion of tooth surface appearance after debonding. The characteristics are visible on the clinical and microscopic levels. The most evident clinical characteristics of teeth that have just erupted into the oral cavity 3 perikymata that runs around the tooth over its surface By scanning electron microscope the open enamel prism ends are recognized as holes In adult teeth the clinical picture reflect and exposure to varying mechanical forces (e.g., brushing habits and abrasive food stuffs). In other words the perikymata ridges are worn away and replace scratched pattern .(Fig.4) Influence on Enamel by Different Debonding Instruments The condition of the enamel surface is evaluated according to the ENAMEL SURFACE INDEX (ESI) system introduced by Bjorn U. Zachrisson and Jon Arthun.15 Score 0 = Perfect surface. No scratches, distinct intact perikymata. Score I = Satisfactory surface. Fine scratches, some perikymata. Score 2 = Acceptable surface. Several marked and some deeper scratches, no perikymata. Score 3 = Imperfect surface. Several distinct deep and coarse scratches, no perikymata. Score 4 = Unacceptable surface. Coarse scratches and deeply marred appearance. By proposing an enamel surface index with five scores (0to 4) for tooth appearance and using replica scanning electron microscopy and step-by-step polishing, Zachrisson and Artun were able to compare different instruments commonly used in debonding procedures and rank their degrees of surface marring on young permanent teeth. (Fig.5) U n i v e r s i t y J o u r n a l o f D e n t a l S c i e n c e s , A n O f f i c i a l P u b l i c a t i o n o f A l i g a r h M u s l i m U n i v e r s i t y , A l i g a r h . I n d i a 7 9 U n i v e r s i t y J D e n t S c i e 2 0 1 5 ; N o . 1 , V o l . 3 The study demonstrated that (1) diamond instruments were unacceptable (score 4), and even fine diamond burs produced coarse scratches and gave a deeply marred appearance; (2) medium sandpaper disks and green rubber wheel produced similar scratches (score3) that could not be polished away; (3) fine sandpaper disks produced several considerable and some even deeper scratches and a appearance largely resembling that of adult teeth (score 2); (4) plain cut and spiral fluted tungsten carbide burs operated at about 25,000 rpm were the only instruments that provided the satisfactory surface appearance (score 1); however, (5) none of the instruments tested left the virgin tooth surface with its perikymata intact (score 0). The clinical implication of the study is that tungsten carbide burs produced the finest scratch pattern with the least enamel loss and are superior in their ability to reach difficult areas pits, fissures, and along the gingival margin. For optimal efficiency the bur must be replaced when it becomes blunt. Increased diameter burs or high-speed equipment also may be used for bulk removal. The oval tungsten carbide bur is useful for removing adhesive remnants after debonding retainers and brackets on the lingual surfaces of teeth. Tungsten carbide burs can give the ideal tooth condition desired after debonding .(Fig.6) 2. 3. 4. 5. 6. 7. 8. 9. 10. CONCLUSION: The present study suggests that an ideal debonding technique should take the least time to debond the brackets with minimal enamel damage and residual adhesive remaining on the enamel surface. In order to achieve a desirable finish to any orthodontic case after debonding tungsten carbide bur is useful for removing adhesive remnants after debonding retainers and brackets on all the surfaces of teeth. BIBLIOGRAPHY 1. Boyer D, Engelhardt G, Samir E. Bishara: Debonding orthodontic ceramic brackets by ultrasonic 11. 12. 13. instrumentation. Am J Orthod Dentofacial Orthop: 1995; 108 (3): 262-266. Eliades T, Viazis AD, Lekka M. : Failure mode analysis of ceramic brackets bonded to enamel. Am J Orthod Dentofacial Orthop 1993; 104 (1):21-26. Williams L and Bishara SE. : Patient discomfort levels at the time of debonding. Am J Orthod Dentofacial Orthop 1992; 101(4):313-319. Theodorakopoulou LP, Sadowsky PL, Jacobson A, Lacefield W. : Evaluation of the debonding characteristics of 2 ceramic brackets: An in vitro study. Am J Orthod Dentofacial Orthop 2004; 125: 329-336. Jena AK, Duggal R and Mehrotra AK. : Physical properties and clinical characterstics of ceramic brackets: A comprehensive review. Trends Biomater. Artif Organs : 2007:20 (2). Karamouzos A, Athanasiou AE and Papadopoulos MA. : Clinical characteristics and properties of ceramic brackets : A comprehensive review. Am J Orthod Dentofacial Orthop: 1997;112 (1): 34-40. Bishara and Trulove. : Comparisions of different techniques for ceramic brackets: An in vitro study. Part I. Background and methods. Am J Orthod Dentofacial Orthop: 1990; 98 (2):145-153. Bishara and Trulove. : Comparisions of different techniques for ceramic brackets: An in vitro study. Part II. Background and methods. Am J Orthod Dentofacial Orthop 1990; 98 (3):263-273. Bishara SE, Fonseca JM, Boyer DB. : The use of debonding pliers in the removal of ceramic brackets: Force levels and enamel cracks. Am J Orthod Dentofacial Orthop 1995; 108 (3):242-248. Kitahara-Ceia FMF, Mucha JN and dos Santos PAM. : Assessment of enamel damage after removal of ceramic brackets. Am J Orthod Dentofacial Orthop: 2008; 134: 548-555. Oliver RG. : The effect of different methods of bracket removal on the amount of residual adhesive. Am J Orthod Dentofacial Orthop 1988; 93(3): 196-200. Krell KV, Courey JM, Bishara SE. : Orthodontic bracket removal using conventional and ultrasonic debonding techniques, enamel loss, and time requirements. Am J Orthod Dentofacial Orthop1993; 103 (3):258-266. Crooks M, Hood J and Harkness M. : Thermal debonding of ceramic brackets: An in vitro study. Am J Orthod Dentofacial Orthop: 1997; 111 (2):163-172. U n i v e r s i t y J o u r n a l o f D e n t a l S c i e n c e s , A n O f f i c i a l P u b l i c a t i o n o f A l i g a r h M u s l i m U n i v e r s i t y , A l i g a r h . I n d i a 8 0 U n i v e r s i t y J D e n t S c i e 2 0 1 5 ; N o . 1 , V o l . 3 14. Artun and Bergland. : Clinical trials with crystal growth conditioning as an alternative to acid-etch enamel pretreatment. Am J Orthod 1984; 85 (4):333-340. 15. Zachrisson B, Arthun J. : Enamel surface after various debonding procedures. Am J Orthod : 1979:75 (2):121137. CORRESPONDENCE AUTHOR : Dr. Neelutpal Bora Lecturer, Department of Orthodontics and Dentofacial Orthopedics Regional Dental College, Guwahati, Assam U n i v e r s i t y J o u r n a l o f D e n t a l S c i e n c e s , A n O f f i c i a l P u b l i c a t i o n o f A l i g a r h M u s l i m U n i v e r s i t y , A l i g a r h . I n d i a 8 1