A number of years ago, as a new company, Invisalign completely changed the world of orthodontic treatment. The concept, and method of moving teeth sequentially was not new. This form of treatment had been used for decades, but it was woefully complicated and required a lot of time and effort in the lab to complete the process. With the technological advances seen in the world of CAD/CAM and 3D digital imaging, it finally became feasible to do this method of treatment in an economical and comfortable way for the patient.
The technology that made it possible is a combination of 3D imaging and the ability to print the captured image in a 1:1 life-size physical object, coupled with the ability to manipulate the digital image. Once it was possible to scan the teeth, or make a super accurate impression of the teeth, then print the digital image from the scan or impression, then manipulate the image without distorting it, it becomes possible to automate the process and make it feasible to do on a large scale. Invisalign was the first company to successfully adapt this CAD/CAM technology to orthodontics and leverage the ability to mass produce the clear aligners that were in common use as retainers.
Backed by technological and manufacturing advances, it became possible to mass produce the clear retainers used as aligners. The initial digital images were manipulated to reflect minor incremental tooth movements from the initial tooth positions to a digitally projected norm or ideal tooth position. Depending on the amount of individual tooth movement needed, and how the cumulative tooth movements were coordinated, a series of models were produced for the fabrication of the clear plastic retainers that would fit each respective model. Although this path from digital models of teeth to actual models of the teeth that could be used to fabricate the series of retainers, now called aligners, made it feasible, it was not quite ready for implementation as the individual retainers/aligners still required manual trimming and polishing. When it became possible to mechanize the process of producing the aligners, everything came together to allow this process to be completely automated and without the restrictions of requiring manual labor in the process, it was made a viable treatment option and made available to patients.
As long as the incremental tooth movements were small enough, and the plastic could get sufficient grip on the teeth so the aligner could exert sufficient force to create tooth movement, treatment with aligners could be successful. One of the major difficulties encountered early on in aligner treatment was that the aligners had a difficult time getting a grip on the teeth that was significant enough to allow the teeth to move an appropriate distance between aligners. If the increments were too small, it would take way too many aligners and too much time to complete the treatment. The solution was to use attachments on the teeth to allow the plastic to be effective in moving the teeth and achieving the treatment result in a reasonable number of aligners.
The attachments perform the same function for the aligners as the braces do for the wires in traditional treatment. Just like the braces, or brackets, the attachments provide a handle for the plastic to grab the teeth and exert a force to move the teeth in the desired direction. The attachments are made of the same special biocompatible composite that adheres the braces to the tooth structure. Both the bond or adhesion, as well as the composite material itself, are strong enough to withstand the forces necessary to move the teeth, the forces generated when chewing, and the significant pressures placed on the attachments when the aligners are inserted and removed.
Attachments have been developed and refined over the years so that there are several shapes, orientations, and sizes used to provide optimal leverage for the plastic to accomplish the desired individual tooth movements. Some tooth movements are accomplished very effectively with a single attachment on the tooth, while other movements require multiple attachments on the same tooth so they can work in concert with each other to efficiently move the tooth and position the root as desired. The attachments have become an integral part of clear aligner treatment, and a necessary component for achieving excellent treatment results.
Although the bonding adhesives used to form the attachments are strong and durable, they may wear, chip, fracture, or dislodge and fall off during treatment. If an attachment becomes worn or chipped, it will be less than optimally effective in accomplishing the desired tooth movements. If an attachment falls off, the aligner may be unable to accomplish further tooth movement, depending on the tooth involved and what movements remain in treatment. Because the loss of an attachment can have an adverse effect on treatment, it is important to report any loss of attachments to the orthodontist as soon as possible. It is helpful if you can tell them what tooth or teeth are missing their attachments. The orthodontist will be in a better position to understand how urgent it is to repair the breakage, and what else may need to be done in conjunction with replacing the missing or damaged attachments. The staff will give you an appointment to make the needed repairs or replacements.
One of the differences between the braces and aligners and how they work to straighten the teeth is that with the braces, the details of tooth position is determined by where the braces are placed on the surface of the teeth, and in relation to the brace positions on the adjacent teeth. With clear aligners, the position that the attachments are placed on the teeth has no bearing on how the teeth are moved or ultimately positioned. The attachments are usually placed to gain maximum effect for the movement they are facilitating. Typically, the attachments are placed closer to the edges of the teeth rather than closer to the gums because when they are placed close to the gums there is very little aligner material at the gum level to grip the attachment and this weakens the grip of the aligner on the attachment.
As one would expect, the bigger the attachment, the more effective it will be as a handle for the aligner to grab a hold of. Cosmetics and irritation are limiting factors to the size of the attachments. You do not want to have an attachment that is large and irritating when you can accomplish the required tooth movement with an attachment that is less intrusive. There is definitely a balance to be had in the size and positioning of attachments.
Virtually every person who has aligners should expect to have attachments placed as part of treatment. With time, experience, and a greater number of people completing treatment with aligners, the number, size, and shape of the attachments has been refined. Currently, the AI used in treatment planning recommends attachments on almost every tooth undergoing a significant amount of movement. The attachments may be changed at different points during treatment to maximize efficiency. The customized shape and size of attachments allows treatment to be completed faster and with better results than when a minimal number of attachments are used. Customized attachments have been a substantial factor in our ability to control the cost of treatment because we are able to be more efficient and complete treatment faster and with fewer aligners. This cost control is very important in today’s world where Bidenflation is adversely impacting everyone’s budget.
Invisalign and clear aligners are a great way to for the orthodontist to craft your best smile. Attachments are a big part of the treatment and should be expected. If they break off or wear significantly, they are likely to be replaced. Let your orthodontist know if you are aware that an attachment is broken or missing. Enjoy your treatment with clear aligners and the benefits this type of treatment offers!