Debonding procedures in orthodontics

1. PRESENTED BY: FASAHAT AHMED BUTT ROLL# 36 GROUP: C DEBONDING PROCEDURES IN ORTHODONTICS

2. OBJECTIVE 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

3. PROCEDURES Bracket removal Steel bracket Ceramic bracket Removal of residual adhesive

4. Steel brackets Ceramic brackets

5. REMOVAL OF STEEL BRACKETS Place the tip of bracket remover against mesial and distal (or occluso-cervically ) edges of the bonding base and cut the brackets off A gentler technique is to squeeze the bracket wings mesiodistally and lift the bracket with the peel force

6. REMOVAL OF CERAMIC BRACKETS 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 mechanism, various ceramic brackets behave differently on debonding More recent ceramic brackets have mechanical lock base and vertical slot that will split the bracket by squeezing

7. CERAMIC BASE DESIGN

8. MEANS OF REMOVAL Mechanical Thermal debonding Lasers Ultrasonic

9. MECHANICAL

10. ELECTROTHERMAL

11. Takla and Shivapuja (1995 ) study in which 30 teeth were schduled for orthodontic extractions 15 extracted 24 days after ETD 7 extracted 28-32 days after ETD 8 were control teeth and debonded by conventional method, with pliers In control group pulp was normal Significant hyperemia in teeth extracted after 24 day In case of teeth extracted after 28-32 day variation was seen from complete recovery to persistent inflammation Jost-Brinkmann et al (1997) did an in vivo study in which 12 human premolars scheduled for extraction were bonded with ceramic brackets which were subsequently debonded using ETD. After 4 weeks, teeth were extracted and histologically examined . No signs of pulpal inflammation were seen

12. LASERS The use of laser eliminates problems like enamel tear outs, bracket failures and pain. Lasers decreases debonding force and less time consuming. Strobl et al (1993) Removal of ceramic brackets from enamel surface by means of laser heating was investigated with the use of C02 and YAG laser Polycrystalline alumina Monocrystalline alumina

13. Laser-aided debonding significantly reduced debonding force by thermal softening of adhesive resin. In 69-75% incident light reached enamel surface when Nd:YAG laser was used which has the potential to cause pain or damage to tooth surface

14. ULTRASONIC

15. DEBONDING METHODS ADVANTAGES DISADVANTAGES Mechanical Low cost Risk of enamel fracture Electrothermal Reduced incidence of bracket failure Short debonding time Potential for pulpal damage and mucosal burn Laser Experimental, but increased precision regarding time and amount of heat application High cost of equipment Ultrasonic Potentially reduced enamel damage Reduced likelihood of bracket failure Adhesive removal after debonding may be achieved with same ultrasonic tip Increased debonding time. Extensive wear of expensive ultrasonic tip Some force required Potential for soft tissue injury

16. ADHESIVE REMNANT INDEX (ARI) Used to evaluate the amount of adhesive left on the tooth after debonding SCORE 0: No adhesive left on tooth SCORE 1: Less than half of adhesive left SCORE 2: More than half left SCORE 3: All adhesive left on tooth with distinct with distinct impression of bracket mesh

17. RESIDUAL ADHESIVE SCORE 0 SCORE 1 SCORE 2 SCORE 3

18. REMOVAL OF RESIDUAL RESIN Ultrasonic scaler Scraping with a sharp bond removing removing plier

19. Burs T ungsten carbide bur Ultrafine diamond bur White stone finishing bur

20. ENAMEL SURFACE INDEX SCORE 0: Instrument tested left the tooth surface with its perikymata intact SCORE 1: Plain cut and spiral fluted tungsten carbide burs operated at about 25,000 rpm were the only instruments that provided the satisfactory surface appearance

21. SCORE 2: Fine sandpaper disks produced several considerable and some even deeper scratches SCORE 3: Medium sandpaper disks and a green rubber wheel produced similar scratches, that could not be polished away

22. SCORE 4: Diamond instruments were unacceptable and even fine diamond burs produced coarse scratches and gave a deeply marred appearance

23. POLISHING