by Kevin J. Hanley, DDS
Ceramic brackets are an aesthetic option that helps patients overcome the stigma of “metal mouth”
Orthodontic treatment has traditionally been a very visible treatment. The appliances have always been very noticeable, and this has always been one of the reasons patients may not pursue treatment. This was particularly true when all the orthodontist had were bands that went on all the teeth. With the advent of direct bonding in the late 1970s, bonding brackets to teeth became possible, decreasing somewhat the appearance of the braces. While not eliminating “metal mouth,” it made it less noticeable.
From Metal to Plastic to Ceramic
It wasn’t long before “clear” braces became available. The first such appliances were made of plastic. They started out clear, but would stain and turn yellow as treatment progressed. The elastic ties used to tie wires would also stain, turn yellow, and be less than aesthetic. The alternative was to use steel ties around each bracket, but this tended to defeat the purpose of aesthetic brackets. Also, since the brackets were plastic, they would flex upon activation of archwires, thereby losing some of the force of the wire. They also broke down very quickly under the forces of mastication, so they needed to be replaced on a regular basis. Plastic brackets were not dimensionally stable, either. This made it very difficult to have consistency when trying to incorporate straightwire angulations and torques into the brackets. Finally, there was an increase in the amount of friction between the bracket and the wire, causing binding of the wire in the bracket, leading to a cessation of movement.
|Kevin J. Hanley, DDS|
In the 1980s, ceramic brackets were introduced. These brackets were color stable and more rigid. They would not flex when a wire was activated, so that the force generated by the wire lost nothing due to the flexion of the bracket. However, the first appliances were extremely difficult to remove at debonding. In fact, enamel fracture during debonding was not an uncommon occurrence. In addition, when used in the lower arch, such brackets could cause severe enamel erosion of occluding teeth. But they were very aesthetic, and, with care, could be used to treat any malocclusion.
Ceramic brackets are glass. They all are made from aluminum oxide. Depending upon the manufacturing process, some ceramic brackets are crystal clear and some are more opaque. Crystal clear ceramic brackets are made from single-crystal aluminum oxide. More opaque ceramic brackets are made from polycrystalline aluminum oxide. Some ceramic brackets are machined from rods of aluminum oxide, while others are injection-molded. Brackets made from single-crystal aluminum oxide are machined. This can introduce stress or fracture points into the material. This makes them more brittle and more prone to fracture during treatment. To overcome this drawback, such brackets are heat-treated or annealed to relieve these areas of stress.
Polycrystalline ceramic brackets can be injection-molded, which makes them smoother and stronger than a machined bracket. It also allows the bracket to be smaller and to follow the contour of the tooth for a more intimate bracket-tooth interface. Polycrystalline ceramic has a denser, more uniform surface, leading to fewer fractures.
|The author uses ceramic brackets to treat those cases that are not good candidates for Invisalign.|
Other Clear Choices
Lingual brackets were introduced in the late 1970s and early 1980s. These were truly aesthetic in that no one could see the brackets, since they were placed on the lingual surfaces of the teeth. However, there were a few drawbacks to the use of lingual braces. One concerned the comfort of the patient. Since these brackets were right next to the tongue, they could impinge on the tongue and cause it to become sore. Some patients found this to be a deal-breaker. Also, working on the lingual is much more difficult for the orthodontist than working on the buccal. (At least, for this orthodontist.)
Finally, with the advent of thermoformed plastics and computers, a truly clear alternative to braces was developed. This is the Invisalign™ system. While this system is excellent for treating some types of malocclusion, and is extremely aesthetic, there are some treatments that cannot be accomplished with it. Extrusion of teeth is difficult, true Class II correction without the use of auxiliaries (such as Class II elastics) is very difficult, and treatment plans calling for the extraction of four bicuspid teeth usually require some treatment with a fixed appliance. Invisalign should only be used with patients who are truly compliant.
What about the other patients? I use ceramic brackets in my practice to treat those cases that are not good candidates for Invisalign or other clear aligner treatment modalities.
|The mechanics used during treatment with ceramic brackets are the same as those used with metal brackets.|
The New Ceramics
Advances have been made in the design of ceramic brackets that make their removal at debonding more like removing traditional metal brackets. I use a ligature cutter to remove the ceramic bracket from the tooth the same way I debond metal brackets. When this is done properly, discomfort to the patient is kept to a minimum. The chance of tooth fracture is greatly lessened as the base of the bracket now flexes as a metal bracket would. This decreases the stress being placed on the crown of the tooth during removal.
My patients request ceramic brackets frequently. I feel comfortable using them because most of the problems associated with earlier iterations of the system have been solved. Ceramic brackets bond just like metal brackets. They come precoated with adhesive so that excess flash is held to a minimum and is easily cleaned from the teeth before the adhesive cures. The adhesive is light-cured, making it possible to achieve exact placement before the adhesive sets. The brackets come with visual aides to help guide the correct placement on the tooth. Because of this exact placement, rebonding brackets due to placement errors is minimal. These alignment tools are easily removed from the brackets once bonding is completed.
Wires with a tooth-colored coating on them make the process more aesthetic, as do elastomeric ties that are more color-stable and less likely to stain. These ligatures still need to be replaced at each visit, as they still do pick up stain. Teflon-coated steel ligature ties are also a less noticeable option.
Drawbacks to Ceramic
There are some drawbacks to using these brackets, however. The ceramic material is brittle, and strength is obtained through bulk. These brackets tend to be larger than their metal counterparts, although not as large as they were originally. They are now more the size of a normal metal bracket. Brittleness may lead to breakage of tie wings. If a tie wing breaks, proper ligation becomes much more difficult, and the offending bracket usually has to be replaced. When replacing such a bracket, you introduce added stress to the tooth with repeated debonding and rebonding.
Because the brackets tend to be more bulky than metal brackets, they can feel larger on the teeth and can be more uncomfortable for the patient to wear. However, with new designs, this has also been minimized. It may take the patient longer than usual to get acclimated to them. This can be important when using ceramic brackets on an adult patient who is more sensitive.
Price can also enter into the equation. Ceramic brackets are from three to 10 times more expensive than traditional metal brackets. How you handle this in your practice is up to you. Some orthodontists charge an extra fee to cover the additional cost. Others, however, will not and will cover the additional cost through the fees they normally charge. This would mean that, if a patient is charged $4,800 for either metal or ceramic brackets, the patients using metal will be subsidizing those patients who want ceramic brackets. In my practice, I charge an extra fee for ceramic bracket use. If patients truly want ceramic brackets, they will pay the additional fee for this service. And that is exactly what it is: a service to the patient, something extra and special.
Using ceramic brackets does not change our office procedures at all. They bond to the teeth like metal brackets. They take no longer to place and cure than metal brackets. In fact, due to the orientation devices attached to each bracket, placement tends to be more accurate than with metal brackets. With the ceramic bracket I use, bond strength is actually stronger than that achieved with metal brackets. Because the ceramic brackets are precoated with adhesive, cleanup is faster than when we bond our metal brackets (which are not precoated).
The mechanics we use during treatment with ceramic brackets are the same as those we use with metal brackets. The ceramic brackets I use have a similar co-efficient of friction as metal brackets. This means that binding of wires in slots is the same whether we use ceramic or metal brackets. When using sliding mechanics to close space, for example, ceramic brackets will perform like metal brackets. We see no difference in the time it takes to close space using sliding mechanics between metal and ceramic brackets. This is very important, as you want a predictable time value for space closure. This allows you to more accurately estimate the length of treatment. As you know, the first question out of a patient’s mouth always seems to be, “When am I going to get these braces off?” Keeping treatment advancing in a predictable manner keeps the office running more smoothly and patients much happier.
With the ceramic brackets I use, debonding is easy and quick. I remove them like I remove my metal brackets, with a ligature cutter. The ceramic bracket is placed on a flexible polymer base. If you place the ligature cutter on this base and squeeze, the bracket pops off the tooth. However, you must make sure you are squeezing the base of the bracket. The ceramic is not flexible, and you can still damage the tooth surface if you are not careful during debonding. All flash around the bracket base must be removed, or you will be unable to squeeze the base of the bracket. Also, there is more patient discomfort with removal of the ceramic bracket. Of course, this is also patient-dependent. More sensitive patients will have more discomfort when removing brackets, be they metal or ceramic.
Orthodontic treatment has always had the stigma of “metal mouth,” or “brace face,” or some other derogatory epitaph. However, with advances in dental materials and computer technology, that stigma can be overcome to some extent. Truly invisible methods of treatment are available today. When such treatments are not appropriate to the patient’s condition, ceramic brackets are a good option. While not totally invisible, they are much less noticeable and can accomplish all the tooth movement that metal brackets can.
- For a complete listing of companies offering ceramic brackets, check out our online Buyer’s Guide.
With more and more adults seeking orthodontic treatment every day, ceramic brackets allow us to offer a more aesthetic alternative to metal brackets and bands. Not every adult is a candidate for invisible aligner treatment. Since we can offer them an alternative that is more aesthetic than metal, we can treat more patients, improving their dental health and self-esteem. And those are two reasons I originally became an orthodontist.
Don’t be fearful. Try ceramic brackets with your patients and witness for yourself their acceptance of this appliance system. Ceramic brackets are just another weapon in our arsenal to give people healthy occlusions and brilliant smiles. Used correctly, they can provide you with a great result and happy patients. And there is nothing better than that.
Kevin J. Hanley, DDS, is in private practice in Buffalo, NY. He has taught orthodontics at both the University of Connecticut and the University at Buffalo. He is also the associate editor of The New York State Dental Journal and the editor of The NYSDA News. He can be reached at