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Original article
Published on 15-06-00

INDIRECT BONDING a new improved adhesive

 

Alberto R. Mazzocchi MD DDS
Bergamo Italy

Corresponding author: Dr. Alberto Mazzocchi Via Rosmini 2, 24100 Bergamo Italy fax: +39-035-231757

Note: The author has no financial interest in the products described in this article.

INTRODUCTION
Though fewer than 20% of orthodontists use an indirect bonding technique (5), there is general agreement that brackets can be positioned more accurately extraorally on a study model than intraorally on teeth (2,3).
This statement is even more important when it comes to using pre-adjusted brackets. Indirect bonding offers significant rewards in term of quality of care and efficiency of treatment (4).

Two main problems are usually related to indirect bonding: additional laboratory procedures and difficulty in achieving consistent and rapid adhesion to teeth. The additional laboratory procedures can be delegated to trained laboratory personnel avoiding time-consuming operations by the orthodontist. Achieving consistent and rapid adhesion can be brilliantly resolved with a new adhesive by 3M Unitek. This product, The Sondhi Adhesive kittm, is composed of two bottles of liquid resin developed specifically for indirect bonding, with 2 main objectives(1):

  • 1-viscosity improvement (with the use of fine particle fumed silica filler)
  • 2-short setting time of 30 seconds and completely cured in 2 minutes.

LABORATORY PROCEDURES

Clean working models in orthodontic stone and eliminate any defects (bubbles, small voids etc.).Apply a thin coat of separating medium to all the tooth surfaces and allow to dry for 1 hour. Place brackets precisely on the model casts using your favorite composite. Concise A+B composite paste or Transbond light curing composite (3M Unitek) can be used. Excess composite should be removed and the position of the brackets should be accurately checked.

Fig.2

Fig.3

Fig.4

  
Warm up the study models to assure complete composite polymerization (30 minutes).
If you use a light-curing composite, cure each brackets for 30 seconds.
Fig.5 Prepare a vacuum-formed or a silicone impression tray. If you use a vacuum-formed tray, we recommend 0.7mm. This type of tray is cheap, predictable and easy to prepare.
White (3) recommends a polymer of ethylene vinyl acetate (Surebond DT-200tm dual temperature hot-glue gun). Kalange (4) uses Esaflextm very viscous Putty.
Fig.6 Remove the bonding tray from the cast, clean excessive material, and trim the tray leaving less than 1/3 of the buccal tooth crowns uncovered.

Etch patient's teeth with an etching solution for 30 seconds. Rinse with water for 15 seconds and air dry for 30 seconds.
Paint resin A on the teeth with a small brush and resin B on the composite in the brackets tray.

Fig.7

 Position the tray over the teeth and apply equal pressure all over the tray for 30 seconds. Let the adhesive set for 2 additional minutes and remove it using a scaler or an orthodontic plier.The initial arch wire can now be inserted.

Fig.8

A thermoformed 2.0-mm disk can be prepared on the normal 0.7mm tray to obtain a rigid envelope that can assure stable and uniform pressure.
Fig.12 Fig.13 Trim the 2.0-mm tray in a shape that covers only the occlusal edge of the teeth. Correct pressure on the tray is obtained by pushing on it with 2 fingers. After the setting time, the 2.0mm tray can be easily removed.
ADVANTAGES
- Accurate bracket placement on study models
- Easy composite placement on bracket mesh (excessive resin can be cleaned up on the models)
- Easy transfer of bonding trays: polymerization begins when resin A (painted on tooth surface) and resin B (painted on bracket mesh) come into contact.

DISADVANTAGES
- Additional set of impressions
- Additional laboratory procedures

Acknowledgments:
the author wants to thank Gaia Locatelli for her kind assistance during laboratory procedure.
  REFERENCES
  1. Sondhi A.  Efficient and effective indirect bonding. Am J Orthod. Dentofac Orthop 1999; 4: 1.352-359
  2. Hickam J.H. Predictable indirect bonding. J Clin Orthod 1993; 27:215-218
  3. White L.W.A new improved indirect bonding technique. J Clin Orthod 1999; 33: 17-23
  4. Kalange J.T. Ideal Appliance placement with APC brackets and Indirect bonding. J Clin Orthod 1999; 33: 516-524
  5. Gottlieb E.L, nelson A.H. Vogels D.S. 1996 JCO study of orthodontic Diagnosis and treatment procedures, Part 1: results and trends. J Clin Orthod 1996; 30: 615-630

To cite this article please write:

Mazzocchi A. Indirect bonding a new improved adhesive. Virtual Journal of Orthodontics [serial online] 2000 June 15; 3(2):[5 screens] Available from URL: http://www.vjo.it/032/sondin.htm

Virtual Journal of Orthodontics
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