“I hate bond failures.” This little bit of philosophical vitriol waspresented to me by my friend, Harry, as he and I settled into ourlounge chairs to enjoy a classic summer evening with our favoritesingle malt scotch. “They routinely throw off a well organizedschedule, stress the staff and me, lead to confrontational conver-sations with patients and parents, and generally complicate ourclinical lives,” he continued, between sips. Harry and I hadremained close friends since we both completed our orthodonticeducation 20 years ago, and he was responsible for cultivating mytaste in scotch whiskey. I have always enjoyed our get togethers,and Harry’s occasional bursts of brilliant observation about life inorthodontic practice could prove to be entertaining and informa-tive. This was not one of those moments.

All bond failures are not the same!

You see, orthodontists tend to think of bond failures in genericterms. “Bond failure” is frequently mentioned as a generic term,almost as if it were a monolithic event. All bond failures are notthe same.

It seemed time to analyze individual bond failures more carefully,and to suggest that the cause of failure should determine thecorrective action.

Bond Failures Are ExpensiveBond failures are invariably more expensive than most of us real-ize. And I don’t mean the cost of the bracket itself. A carefulunderstanding of the process actually reveals that the cost of thebracket is virtually inconsequential. Although no one enjoysspending more on operating overhead than is necessary, it doeslittle good to focus on the cost of the bracket, which is, literally,the smallest part of the problem. Lost clinic time and lost treat-ment time are the major concerns, and the major source of addedcost in treatment induced by bond failure. Add the cost of badpublic relations, patient perception, etc. After all, it is never thepatient’s fault, is it? With the exception of a few rare honest citi-zens, who will confess to crunching on ice cubes and biting on

pen caps, the degree of inventiveness most patients can display inexplaining how a bracket came off can be fascinating. “She wasjust sitting there, sucking on a marshmallow, and it just cameoff!”, we are told by earnest sounding parents. The unspokenimplication — did you use cheap glue, Doctor? Sooner or later,we all learn that arguing with people about this sort of thing israrely productive. Except in cases of egregious and repeatedabuse, it is not worth the time or the effort. Remember, peopledon’t like to lie, and they resent the people they have to lie to.

The True Cost of Bond FailuresLet’s give some careful thought to what the actual cost of bondfailures can be. In the best case scenario, if there is no loss oftooth movement, there is a minimum investment of 20-30 min-utes of chair time. This would include front desk time in takingthe phone call from the patient, scheduling the patient, untyingan archwire, preparing the tooth, rebonding the bracket, and rety-ing the archwire. Add to that the cost of tray set ups, sterilization,etc. I don’t care how efficiently you run your office, even thisbest case scenario will add a cost of $70 to $80 for a single bondfailure. Even if the patient is aware that they did something tocause the bond failure, they are still irritated by the inconven-ience to them, having to take time from work or school, and youwill generally be the recipient of those bad feelings. If there issome loss of tooth movement, such as the relapse of a rotation,then the average cost of a bond failure will be 30-40 minutes ofchair time, and two appointments. This is further enhanced if youhave to drop to a lighter archwire to recover a displaced or rotat-ed tooth. In this instance, the cost of a bond failure may rangebetween $150 to $200. And I must emphasize the possibility thatthe projected treatment time has been increased, with the result-ing loss of public relations and rapport with your patient. Inshort, nothing good ever came of a bond failure.

Rather than argue about these events with our patients, I believeit would be much better if we were to focus on the cause of bondfailures, and to take measures designed to minimize them. Wecan’t make the problem go away, so we might as well focus onhaving it visit us less frequently.

Dr. Anoop Sondhi received his dental degree from the Indiana University School of Dentistry, and his post-graduate certificateand M.S. in Orthodontics from the University of Illinois in 1977. Following his graduation, he was on the graduate faculty of theDepartment of Orthodontics at Indiana University. Since 1988, he has been in full-time private practice in Indianapolis, and continues as a Visiting Professor for several graduate programs in orthodontics.

Dr. Sondhi has used indirect bonding for the past 16 years, and has presented seminars and continuing education courses toseveral dental and orthodontic organizations in the United States and Canada. He has also lectured in Europe, Africa, Asia, andLatin America. In addition to his orthodontic practice, Dr. Sondhi devotes a significant amount of his clinical work to the diagnosisand management of patients with disorders of the temporomandibular articulation. Dr. Sondhi also serves as a consultant to theAmerican Journal of Orthodontics and Dentofacial Orthopedics.

The Truth About Bond Failuresby Anoop Sondhi, D.D.S., M.S.

The Source of Bond FailuresAs I mentioned earlier, all bond failures are not the same. Forexample, if the bond failure occurs at initial archwire insertion,that is obviously not the patient’s doing. The cause of such bondfailure would be either a technique error, or material contamina-tion during the bonding process. Since I use indirect bondingalmost exclusively, if the bond failure occurs at tray removal,then the problem is also obviously related to technique or mate-rial contamination. In a recently published article1, we presenteda new resin developed specifically to deal with this problem. Inthe enclosed graph (Fig. 1), it is evident that this material has anextremely fast cure rate, and that bond strength at the five minutemark is substantially higher than resins we have previously used.The five minute window is important because that is when thetray is removed, and the archwire inserted. That is why, in theindirect bonding technique we have developed1, I use vacu-formed trays. Although it makes the tray difficult to remove, it isan excellent test of bond strength at the chair side. If the bracketis going to fail, it is better that it fail during the bonding appoint-ment, when it can be easily rebonded. If the patient has to returnthe following day, that is a ridiculous inconvenience to them.While the other resins that we compared will eventually catch upin bond strength, that will not help in dealing with the first causeof bond failure that we are discussing here.

If a bond failure occurs within 24-48 hours of appliance place-ment, I believe that the source of the problem is still techniqueerror or material contamination. The reason is quite simple.Following the initial banding appointment, most patients haveteeth that are tender enough that they are unlikely to bite down onanything hard, or to fiddle aggressively with their appliances.There is little point in glaring at a patient that arrives the day afterthe bonding with one or two loose brackets. Since the probabilityof technique error or material contamination is high, it wasn’tthe patient, it was us. This is where APC™ Brackets and Tubeshave proved to have a significant advantage, since material con-tamination is virtually eliminated, and the potential for an error in

technique greatly reduced. If the bond failure occurs 48-72 hoursafter bracket placement, it gets a little more difficult to identifythe source. It could still be technique error or material contami-nation, of course, but the patient may now be contributing to theproblem. This could be due to the fact that the tenderness of theteeth has started to subside, and the patient becomes more adven-turous with hard and sticky objects. After 3-4 days have elapsed,the likelihood that a bond failure would be due to technique erroror material contamination is extremely low. Generally, bondfailures after this time are due to patient abuse, with one excep-tion. If a bond failure occurs during archwire tying, we shouldthink carefully about how we, or our staff members, are tyingin archwires.

I find it useful to explain this to patients, so that they understandthat 3-4 days following appliance placement, the resin will becompletely cured, and that “the glue doesn’t dissolve”. In essence,while I rarely want to argue with a patient about whose fault it isthat the bracket came off, except in cases of egregious abuse, wedo gently remind them that brackets are rarely suicidal, and do notgenerally jump off the teeth spontaneously.

Improper Archwire TyingThere is only one point that I really want to make here. Whentying in an archwire that is active to a rotated tooth, or a rectan-gular archwire that has a significant amount of torque, it is impor-tant to remember one detail. If you simply force the archwire intothe bracket slot with the force of the ligature itself, this places ashear force on the bracket (Fig. 2). Well, if you think about theprocedure we follow for debonding, that is exactly how youremove a bracket from a patient’s tooth. Regardless of whichdebonding instrument you might use, the preferred method ofremoving the bracket from the tooth is to apply a shear force to it.This, in my opinion, increases the probability of bond failure dur-ing archwire tie in, because the activation procedure is similar tothe debonding procedure. It is my recommendation, therefore,that the archwire be pushed into the slot with a ligature director,and then the archwire be engaged completely in the slot with theligature pliers (Fig. 3). Similarly, when tying in a torqued arch-wire, it will be substantially better to torque the archwire into theslot with a torquing key (Fig. 4), instead of trying to engage thearchwire into the slot with the ligature tie itself. What we want toavoid here is a bond failure induced by a shearing force.

Figure 1:Bond Strength Comparison at 5 minutes

Figure 2:Ligature Tying creating Shear Force

Indirect Bonding vs. Direct BondingRegardless of whether brackets are placed with direct bonding orindirect bonding, the bottom line remains that we eventually wantadequate bond strength during treatment to minimize the numberof bond failures. Accurate bracket placement on the anterior teethcan generally be achieved with both indirect and direct bonding,of course, but bracket placement on posterior teeth is a differentmatter. As a general rule, accurate bracket positioning withdirect bonding on posterior teeth is substantially less accuratethan with indirect bonding. If direct bonding posterior teeth isn’tparticularly easy, rebonding them isn’t any easier! Therefore, the

more accurate the bracket positioning at the initial applianceplacement, the better. This is where indirect bonding presents sub-stantial advantages. As mentioned earlier, we have developed acohesive indirect bonding system, which is supplemented with aresin developed specifically for this purpose1. This has reducedtime lost in treatment, and the cost of rebonding, substantially. Itis my opinion that previous failures with indirect bonding systemswere related to the use of resins that had actually been designedfor direct bonding, and were merely adapted for indirect bonding.

ConclusionsI have tried to elucidate the cause of bond failures followingappliance placement, and believe that the breakdown of possiblecauses explained above allows us to focus on the specific cause,and to implement the appropriate corrective action. If the bondfailure occurs the day after appliance placement, I would stronglyurge you to consider the possibility of material contamination, andto analyze your own bonding technique carefully. If the bond fail-ure occurs several days or weeks after appliance placement, quitbeating up on yourself! Some of the marshmallows out there canbe very hard! Focus on reducing the number of bond failures thatyou can control, and watch your operating overhead, and yourstress level, decrease. ■

REFERENCE

1 Sondhi, Anoop: “Efficient and Effective Indirect Bonding” – Am J Orthod Dentofacial Orthop, 1999; 115:352-9.

Reprinted from Orthodontic Perspectives Vol. VI No. 1. © 1999 3M Unitek

Figure 3:Shear Force Reduction: Archwire pushed into Slot with LigatureDirector, then tied in with Ligature Pliers

Figure 4:Shear Force Reduction: Archwire pushed into Slot with TorquingKey, then tied in with Ligature Pliers