indirect bonding

bonding technique in orthodontics, indirect bonding

1. INDIRECT BONDING Presented by :- Kumar adarsh

2. INTRODUCTION TYPES OF TRANSFER TRAYS METHODS OF INDIRECT BONDING THOMAS METHOD KNIGHTS METHOD SONDHIS METHOD CONCLUSION 2

3. INTRODUCTION In the past, the best clinical results were achieved by orthodontists who had the best wire bending skills. However, "the best results in the present and in future will be achieved by those orthodontists who are best at accurate bracket positioning" 3

4. For the past 50 years, since the introduction of acid etching by Buonocore in 1955, major improvements were achieved in bonding brackets to the teeth. In 1964, Newman first tried to bond orthodontic brackets to teeth using acid etch technique and an epoxy-derived resin. 4

5. To reach the goals of better bonding Silverman and Cohen introduced the first indirect-bonding method in 1974. They used methyl methacrylate adhesive to attach brackets to model casts in the laboratory. An unfilled BisGMA resin was used as an adhesive between the etched enamel and a previously placed adhesive. 5

6. Direct Bonding Indirect Bonding Description Brackets placed directly on each tooth one at a time, and adjusted by orthodontist until reasonable position achieved Brackets placed on models of patient’s teeth. Full set of brackets transferred to mouth with transfer tray Chair time 1.5 to 3 hours (Full Set) 30- 45 minutes (Full Set) Accuracy Low to Moderate (Accuracy decreases in posterior region) High Patient Comfort Moderate High Results Variable: subsequent bonding appointments needed to reposition brackets for accuracy Quick, Precise Bracket Placement INDIRECT BONDING OVER DIRECTBONDING

7. Types of Transfer Trays Polyvinyl Silicone – Putty Putty and activator are mixed in a kneading action and rolled cylindrically Thomas RG. Indirect bonding, simplicity in action. J Clin Orthod . 1979;13:93–105

8. Reprosil impression material tray- is applied with a syringe

9. Clear Polyvinyl Siloxane Trays

10. Bioplast or biocryl trays- A Biostar unit to vaccum form a 1 mm thick layer of Bioplast , overlayered with a 1 mm thick layer of Biocryl sheet is used. Ref:- Sondhi A. Efficient and effective indirect bonding. Am J Orthod Dentofacial Orthop . 1999;115:352–359

11. Light polymerized resin composite trays First, block out the bracket undercuts and slots with plaster. Coat the blocked-out bracket with a resin separator, and cover it with a quick-curing acrylic resin RYOON-KI HONG et al JCO/AUGUST 2000

12. Surebonder DT-200 hot glue gun uses a polymer of ethylene vinyl acetate to form a clear transfer tray matrix for transferring accurately placed brackets to the teeth White L. “New and improved indirect bonding technique” J Clin Orthod 1999; 33:17-23

13. PREVIOUS RESINS USED IN INDIRECT BONDING With the increasing popularity of indirect bonding over the past 2 decades, different methods of bonding the brackets to the teeth have been developed. When brackets had been positioned on the models with candy or various glues, the bonding was accomplished with a filled resin, such as Concise. The indirect transfer trays usually were formed with silicone tray materials. 13

14. It became increasingly evident that one of the deficiencies in the available systems came from the fact that all the resins and procedures originally had been designed for direct bonding and subsequently had been adapted for indirect bonding. The property of working time for the adhesive has no advantage in indirect bonding because an extended cure time is unnecessary once the tray has been placed. This led to the development of a resin designed specifically for indirect bonding. After some innovation, laboratory testing, and clinical trials, an efficient and effective indirect bonding procedure has been developed. 14

15. DEVELOPMENT OF A CUSTOMIZED RESIN BASE In an effort to determine the best method for preparing a custom resin base, a number of clinical trials were attempted. It is found that a light cured resin is a quick and efficient material for placing brackets on models and for forming a custom resin base. Use of adhesive precoated brackets eliminates contamination and reduces laboratory time to a minimum because individual brackets do not need to be sorted or have resin applied to the base before placing on the model. If precoated brackets are not used, then it is recommended to use Transbond XT as the material of choice for preparing the resin bases. 15

16. A New Indirect Bonding Resin This material was designed with several objectives in mind. An unfilled resin lacks any Significant viscosity and is not capable of filling the small imperfections in the custom base formed with light cured resin or any imperfections in the fit of the custom base against the enamel. The viscosity of this resin was increased using a fine particle fumed silica filler(about 5%) so that it would be capable of filling such voids without compromising any bond strength. The resin was developed with a quick set time of 30 seconds, thereby significantly decreasing the time needed to hold the bonding tray. 16

17. VARIOUS METHODS OF INDIRECT BONDING 17 Many techniques are available which differ by The way brackets are attached temporarily to models. Type of transfer trays used. Adhesive or sealant employed.

18. THOMAS INDIRECT BONDING TECHNIQUE - ( Double sealant technique) Laboratory Procedure An excellent alginate impression Separate, fill any holes Allow model to dry overnight. Small dots of each bonding resin paste-Catalyst and Universal resin is placed side by side on a paper mixing pad. Bracket position on model 19

19. Dots of bonding resin is mixed and applied to the back of the bracket base. Excess flash is removed Allow bonding material to set at least 10 minutes before forming tray. Now the tray material is cut The model is dipped into water (3-5 seconds) and placed under a dry heat source with the arch blank on top. 20

20. The model with the heated arch blank is placed in the vacuum former and vacuum is applied. After good adaptation has been achieved, cold water is poured into the top of the vacuum former to hasten the cooling of the tray material. The model is now removed from the vacuum former and placed into a bowl of water until it is saturated. This allows the bonding agent to be released from the stone before the tray is removed from the model. 21

21. The tray is removed and trimmed 1-2 mm away from the clinical crowns of the teeth with lab scissors. The tray is then cleaned under running water with a brush. The midlines of the tray are marked with a Marker, to help identify the midline during bonding. The backs of the bases are lightly abraded with a stone point. Air is blown to eliminate residue. 22

22. Clinical Procedure antisialagogue like Banthine 30 minutes before starting the procedure. The inside of the tray is then painted with liquid "sealant" catalyst resin. All teeth that are to receive brackets are polished. The teeth are conditioned using a small sponge pellet soaked in 37% phosphoric acid for 30 seconds. 23

23. The conditioner is thoroughly rinsed from the teeth and the teeth are again air dried. The teeth are painted with liquid "sealant" Universal resin. The tray is then inserted into the mouth, seated fully and held to place for 1½ minutes. These same procedures are then repeated in the opposite arch before removal of the tray. The tray is then removed from the mouth from the lingual toward the buccal, peeling the tray off, leaving the brackets behind. Dental floss should be passed through each individual contact to ensure that no bridging has occurred. 24

24. 2. KNIGHTS METHOD - The Thomas technique is the foundation for contemporary indirect bonding. In this procedure, the brackets, with filled composite on their bases, are bonded directly to the working casts. After bracket positions are accurately recorded with a plastic template, the unfilled resin (sealant) is added to both the tooth surfaces and the composite bases. The entire tray, with the brackets encased, is seated in place, resulting in minimal flash and relatively easy clean-up. The following indirect-bonding technique is a modification of the Thomas technique using Therma Cure composite and Light vinyl polysiloxane impression material. 25

25. Impressions for Indirect Working Casts – it’s the same as for Thomas technique. Preparation of Working Casts Pour the impressions immediately in a hard stone. 2. After the stone has set, the casts are separated from the impression trays. When the casts are dry, fill in any voids with a light-cured adhesive gel, and cure for 20-30 seconds. 26

26. 3. the incisal edges, mesiodistal center points, and long axes of the teeth on each cast are marked with a pencil, along with the preferred incisogingival positions of the bracket slots. 4. Two thin coats of liquid separating medium is applied to the facial surfaces of the teeth on the cast, and allowed it to dry. 27

27. Placement of Brackets on Cast 1. The Therma Cure composite resin is applied to the mesh pad of each bracket, using a “buttering” motion to cover all of the mesh. 2. The brackets on each cast are placed with firm pressure, and positioned according to the pencil marks. 28

28. Curing of Composite Resin The casts are placed in a heated oven to cure .( Therma Cure requires 15 minutes at 325°F. ) 2. The casts are allowed to cool, and removed from the oven. 29

29. Fabrication of Transfer Trays Reprosil impression material is applied with a syringe over the thermally cured brackets from the facial surfaces, and cover each bracket. The material is extended onto the occlusal or incisal surfaces and partly onto the lingual surfaces, but the undertray should not be made unnecessarily thick. 30

30. 2. Vacuum-form Essix .020" (.5mm) or .030" (.75mm) clear thermoplastic material over the cast, brackets, and undertray complex. 31

31. After cutting away the excess thermoplastic material, the assembly is soaked in warm water for about five minutes, then both the trays are separated from the cast. Trim the trays with scissors. Rinse away residual solidified release material and other debris from the undertray and brackets. Inspect the composite pads, and trim off any flash. 32

32. Chair side Bonding Procedure 1. To remove the air-inhibited layer of adhesive, lightly abrade the composite on the back of each bracket base with a diamond bur or Microetcher , or simply scrape the composite base with a cleioid instrument. 33

33. 2. Isolate a single arch, etch the enamel, and rinse. Dry with an air syringe. 34

34. 3.Mix two drops each of Enhance A and B primer. Apply the mixture to the composite bases and the tooth surfaces. 35

35. 4. Mix unfilled bonding resin, and quickly apply it to the composite bases of the brackets and to the teeth . 36

36. 5. Seat the tray immediately . Hold the tray in place for one minute, then allow the tray to remain in place for about 4 more minutes. 37

37. 6. Remove the clear overtray material. 38

38. 7. Tear the flexible undertray from the teeth with an explorer or scaler . Use a gentle, rolling motion from the lingual surface of the flexible tray to avoid dislodging the brackets. 39

39. 8. Inspect the brackets. Floss interproximally to remove any bridging of the unfilled resin. There should be virtually no flash of filled bonding resin around the bracket bases. 40

40. SONDHIS METHOD Laboratory procedure Preparation of bonding trays 1. Working models in orthodontic stone, prepared from accurate alginate impressions, are necessary. 41

41. 2. A thin layer of separating medium should be applied to the models and allowed to dry for approximately 1 hour. 42

42. 3. If Adhesive Coated brackets are used, the preoriented brackets may be removed directly from the sealed blister and positioned on the individual teeth. The excess adhesive should be removed, and the position of the bracket carefully checked with a bracket gauge. If noncoated brackets are used, then Transbond XT Light Cure adhesive should be placed on the mesh pad of individual brackets before they are positioned on the model. 43

43. 4. Once all brackets have been placed, any excess should be removed. 5. Once all the bracket positions have been checked, the upper and lower models should be placed in the curing unit and cured for 10 minutes. 44

44. 6. Before forming the indirect bonding trays, it is recommended that significant undercut areas, such as hooks, be blocked out with wax. 45

45. 7. The indirect bonding trays can now be placed over the brackets . 1 mm thick layer of Bioplast , overlayered with a 1 mm thick layer of Biocryl is used 46

46. 8 . The bonding trays are now removed from the models and may have to be sectioned off with a bur. It may be necessary to tease the tray off with a scaler. 47

47. CLINICAL PROCEDURE : Preparation of the patient 1. Pumice all teeth. 2. Rinse and suction well with water. 3. If there are bands to fit, this should be completed after the indirect bonding procedure has been completed. 48

48. Placement of Bonding 1. Whether the indirect bonding procedure can be completed with a single tray for the entire arch or whether the tray needs to be sectioned into two segments is a decision based primarily on the degree of isolation that is feasible. If there is significant crowding, it may be easier to section the tray. 2. Examine the trays carefully for any remaining separator or tray material covering the adhesive custom base on the bracket. 49

49. 3. Isolate the teeth that are to be bonded with plastic cheek retractors, Tongue Away, and cotton rolls. 4. Using air syringe, dry teeth thoroughly. 5. Etching solution is applied onto the teeth and kept for 15 seconds. 6. After 15 seconds, rinse with a steady stream of water for 15 seconds. 50

50. 7. A . If the clinician chooses to use Moisture Insensitive Primer on the enamel surface before the indirect bonding procedure, then the air syringe should be used to remove excess moisture. B . If Transbond MIP is not used, and the bonding is accomplished with the indirect bonding resin, then all visible moisture should be removed. The etched teeth should have a frosty appearance. If a frosty appearance is not apparent, repeat the etching process for 15 seconds. 51

51. 8. Small amounts of the indirect bonding Resin A and B liquids ( Sondhi rapid set) should be poured into the wells. Care should be taken to keep liquids separate. 52

52. Resin A can be painted onto the tooth surface with a brush, and Resin B can be painted on the resin pads in the indirect bonding tray. 53

53. 9. If too much resin has been placed on the enamel, gently remove the excess with a brush. 10. Position the tray over the teeth and seat the tray with a hinge motion. With the fingers, apply equal pressure to the occlusal , labial, and buccal surfaces. Hold for a minimum of 30 seconds. Allow 2 more minutes of cure time before removing the tray. 54

54. A , Placement of mandibular bonding tray. B . maxillary and mandibular bonding trays in place. C . removal of mandibular bonding tray. 55

55. 11. Remove the tray by using a scaler to peel the tray from the lingual to buccal . Use extreme care when removing the tray from around bracket wings. 56

56. Disadvantages of indirect bonding Technique sensitive. Increased lab time. Risk of adhesive leakage to gingival embrasure could lead to difficult oral hygiene management. ANGLE 2004 by Polat et al. Removing adhesive is difficult & time consuming. Achieving consistent & predictable adhesion is difficult. Accidental removal of brackets with tray is not unusual. Adequate bond strength shortly after sealant application is mandatory.(To withstand force during tray removal ) Failure rates are slightly higher – Zachrisson & Brobakken 57

57. Conclusion When the laboratory and the clinical procedures are strongly adhered , indirect bonding is undoubtedly a valuable technique. It proves itself by saving chair side time which is the most valuable for a practitioner as better treatment results can be obtained if the brackets are positioned accurately.

58. References Xubair,grabber,vanarsdall,vig;Orthodontics current principles and techniques,5 th edition Thomas RG. Indirect bonding, simplicity in action. J Clin Orthod . 1979;13:93–105 Knight RG; a new look at indirect bonding; J Clin Orthod 1996, 30(5);277-81 Sondhi A; Efficient and effective indirect bonding, Am J Orthod Dentofacial Orthop 1999;115:352-9

59. Thank you…