Indirect bonding is an advanced method of bracket placement used in accordance with straight wire orthodontic systems. The basic process includes taking an accurate PVS impression or scan, brackets placed on the model (plaster or printed), indirect bonding trays formed, and the indirect bonding trays placed intra-orally.
Indirect bonding can greatly increase the accuracy of bracket placement. The benefit of accurately placing brackets 7-7 will decrease treatment time by having fewer bracket repositions. This process also allows for the alignment of the second molars from the beginning of treatment. While the process does increase lab expenses for the fabrication of the trays, this cost is typically offset by the reduction of clinical chair time, number of appointments necessary to complete treatment as well as total treatment time.
Patient comfort can also increase with this process. Chair time and the time the patient is in the retraction system is reduced as well. Typically, a full upper and lower indirect-bonding case can be completed in one 60-90 minute appointment. The time the patient is in the retraction system is kept to a minimum by the clinician placing the trays and completing the light-cure process.
How do you know if indirect bonding is right for your office? Here are some questions that may aid your decision:
If your answer to any of these questions is yes, indirect bonding may be a solution for you.
- Is your percentage of patients over estimated completion date too high?
- Is your number of bracket repositions too high?
- Is your number of appointments during treatment too high?
- Do you need to reduce doctor time in your schedule?
Choosing the correct indirect-bonding process is an individual decision based on several concerns. Turnaround time, cost, staffing, as well as other concerns will help determine which option is best for you and your practice. Trays can be fabricated either in-house or outsourced to several different companies. There are several fabrication processes for the in-house production of trays—putty trays, two-part clear trays, and the "glue gun" method are some of the ways offices make trays. Making the trays in-house allows more schedule flexibility and is often less costly. This process, however, does not allow the advantage of computerized bracket placement, treatment planning or digital study models.
Outsourcing the tray fabrication may allow the doctor to take advantage of computerized bracket placement and treatment planning. The programs allow the doctor to see the proposed finished outcome for each case. The computerized treatment planning also allows doctors to explore different treatment options—e.g. extraction vs. non-extraction. Digital study models are included with the cost of the tray fabrication and computerization. Turnaround time varies between sources and can be a challenge with scheduling. Once the system is in place and the team becomes comfortable, this is not usually a concern.
The reduction of chair time, bracket repositioning, total number of appointments needed, as well as reduction of total treatment time usually offset the cost incurred for outsourcing tray fabrication. Computerized bracket placement often aids in this process.
The implementation of scanners can make the switch to indirect bonding a much easier process. With the increased accuracy of a scan, the bonding process typically has a lower failure rate. There are several scanners on the market that can produce STL files that are accepted by traditional labs. Your local lab may or may not be set up to accept these.
The introduction of scanners into the process opens up many options for indirect bonding. You can send the scan to a lab that can fabricate models with the aid of a 3D printer and indirect-bonding-trays production for chairside delivery. These labs can also fabricate models that are delivered to the office of in-house fabrication. With proper implementation both options can be highly successful.
Computerized bracket placement also presents several options. The ability to visualize the finished case may be a great tool in achieving the optimal final result. Some of the options that are on the market include Specialty Appliances, Insignia, and Arcad. This process allows you to view the proposed finished case prior to approving and ordering indirect-bonding trays. Each of these systems has pros and cons. Insignia can produce custom brackets as well as using traditional Damon brackets. Their system includes trays, brackets and all archwires for the case. Other systems include your brackets and custom indirect-bonding trays. Systems that include a custom base on the brackets can help in the bonding process.
If you are taking impressions, the impression's accuracy is a critical part of the indirect-bonding process whether you choose to fabricate the trays in-house or outsource this process. A quality PVS impression material and properly fitting impression trays are a necessity for the fabrication of indirect-bonding trays. Any distortion, incomplete registration, or change in tooth structure may compromise the fit of the indirect-bonding trays. All plaque build-up needs to be removed prior to taking the impression. If the office chooses to use an alginate material for the impressions, accurate measurement of the powder and water is critical to the quality of the impression.
The pour-up of the impression is also important for the in-house fabrication process. Improper water-to-powder ratio, mixing and removal of bubbles are areas that can lead to a less-than-perfect stone cast. Adhesive is used to place the bracket on the model. This makes a custom base that is formed to the individual tooth structure. The need for an accurate impression is critical to the indirect-bonding process.
The choice of tray fabrication determines the time frame between impression and chairside indirect-bonding delivery. This timeframe can be anywhere from one to three weeks depending on the source. A longer period between impression and delivery of the tray may increase the chance of the tray not fitting properly. Eruption of teeth or general shifting can alter the way the tray sits.
There are several types of adhesives that can be used with the indirect-bonding process. Chemical cure, light cure, and A & B resin systems are utilized in many offices. Each adhesive has
benefits and drawbacks. The light-cure system has had a great success rate in many offices. Implementation is the key to the level of success you can expect.
Clinical training is an area that some offices neglect. Often without clinical training there is a higher level of failure. The bonding technique is simple but very sensitive to any variations. Hands-on training will explain the technique and observe the clinicians as they actually complete an indirect bonding on a patient. A trainer can assist the clinician with preparation, loading the tray with adhesive, isolation, placement of the trays, and light curing, as well as the rebonding protocol for any bracket failures when the trays are removed. Without this type of training, clinicians often do not know the importance of each step and how to achieve the highest level of success.
If the office is using a light-cure adhesive for the indirect-bonding process, proper light use and maintenance need to be followed. Proper curing time needs to be established by following manufacturer instructions and a weekly maintenance protocol for the curing lights must be strictly followed. Prior to and following the bonding process, the curing light intensity needs to be checked to ensure adequate output is being maintained during the entire bonding process.
As with any process in the office, troubleshooting comes into play. Some of the key areas to review are the impression and pour-up phase of the process, if you are not using a scanner. If this portion of the process is not perfect, the remaining steps can be compromised and can increase bond failures chairside. Consistency between all clinical team members, chairs, and bonding techniques will increase the success rate for the office. It's necessary to train all clinical team members to follow a strict protocol.
Making the switch to indirect bonding can be difficult but is definitely something to consider if you need to reduce time in your schedule and find yourself doing too many bracket repositionings. After doing research and following the necessary steps and protocol you will find that indirect bonding is the solution to your problem.
Andrea Cook is an orthodontic clinical consultant for orthodontic offices across the country. Andrea works with teams to increase efficiency, improve communication and to guide the office to a new level of excellence. Her years of experience include working in single- and multi-doctor practices. She has extensive experience as clinical coordinator for a multi-doctor practice seeing more than 120 patients per day. Andrea's experience allows her to understand and address the concerns of the clinical team.