Retention and Maintenance After Orthodontics

 

Retainers and maintaining straight teeth following Orthodontic Care

 

 

Orthodontic treatment to correct crooked teeth, improve poor bites or restore ideal function for patients has several stages from starting with the examination by an accredited and knowledgeable Orthodontist, to taking diagnostic records and formulating a treatment plan to placement of appliances and alignment of teeth.  Finally, after teeth are aligned and function restored, the last step of Orthodontics, perhaps one of the most important stages, is the retention of the correction as bone gets more solid and the teeth settle back into equilibrium.  We call this Retention and Maintenance.

 

Many times in my 20+ year career I have given full instructions to a patient, informed them (and their parents if applicable) about importance of retainers even including written instruction sheets with illustrations and setting up follow-up appointments, only to see patients return with relapsed teeth complaining that they were not told to wear retainers.  It can be maddening; we are not in the business to introduce conflict between ourselves and our patients and it is certainly no practice builder to do so.  It is also frustrating since it may have taken significant effort and time on our part to provide the correction (we are proud of our work!) only to see it slip away slowly over the next year from a lack of adequate maintenance and/or retainer wear.

 

 

As Orthodontists, it is our responsibility to explain and reiterate that the only proven way to having teeth relapse (move back toward the original positions) is through wearing a retainer and following up with regular maintenance just as you would change the oil on a new car or take expensive/delicate clothing to a dry cleaners.

 

In fact, teeth shift throughout life even without orthodontic correction; forces in the mouth change, bone support changes, habits change; all things that slowly alter the equilibrium.  So when teeth are moved into new positions, they must be held in position (rigidly at first and periodically over time).  The better the correction and the better the orthodontics, the better the teeth will stabilize and the more likely a patient can walk down to limited retainer time (1/wk or less) without relapse.

 

Types of Retainers

 

 

 

Fixed Retainers are bonded to the back of teeth with resin/cement to hold the teeth to the exact post-orthodontic positions.  The advantage is clearly that compliance is not needed to remember wearing retainers.  But there are disadvantages that many times outweigh the advantages for Orthodontists to regularly prescribe such fixed retainers.

 

For one, there is generally significant breakage to the retainers dislodging them and requiring re-bonding and repairs regularly.  These can become quite costly (for the Orthodontist and the patients) in both money and time.

 

Secondly, if there is breakage, it is usually off just one or two teeth and is not noticeable until a tooth moves away from the fixed wire/bar.  By then, a different retainer or even limited braces/aligners may be necessary to re-correct alignment.  This can happen due to diet (ice/nuts/hard foods) but can also be from specific occlusal forces being heavier on one tooth more than others.  Orthodontists who follow their patients for at least two years following correction would see @20% of all fixed wires becoming loose and requiring re-cementing.

Thirdly, plaque formation around fixed wires can be difficult to clean and can lead to decay in areas difficult to see and difficult to restore.  Holding plaque in these areas can also increase the risks of gingivitis and periodontal disease when left for years.

 

It is ironic that so many Invisalign providers will over-expand the arches until the teeth line up then place a permanent and indefinite fixed retainer to hold the unstable “alignment” all the time selling Invisalign as better to clean than braces because trays are removable (which in itself has been proven untrue; see my blog article on “Debunking the Myth of Superior Oral Hygiene with Invisalign” from 2018 study in the AJODO).

 

Lastly, placing fixed wires to hold teeth immediately after orthodontics prevents the natural “settling” of teeth into the best fit possible.  Most of the time, orthodontics will give us a 90 to 95% of “best fit” however due to the natural variation between tooth sizes and morphology, it usually takes some settling of the teeth up and down in certain areas for teeth to fit best.  Fixed wires do not allow this and may hold the teeth in unstable positions that can lead to relapse many years later if and when the wire is removed.

 

Removable Retainers are made of plastic or acrylic, usually with wires added for strength and to allow adjustment.  Removable retainers are usually worn full time initially following removal of orthodontic appliances/braces for a certain period of time then reduced to night time wear and eventually down to one night per week or less depending on the degree of the original correction and the forces in the mouth.

 

 

Removable “Hawley type” retainers have the advantage of allowing teeth to move slightly up and down while still maintaining the correction of rotations or alignment.  This allows teeth to settle into more stable positions that can reduce the need for future retention and eventually allow the discontinuance of regular retainer wear.  Every patient is different and unique so there are some patients that may have to wear retainers nightly and indefinitely to maintain good alignment.

 

Removable “Essix type” or clear aligner trays wrap around and over all teeth tightly and will hold whatever position the teeth were in at the time of completed treatment however over time, usually within a couple of months), the trays get weakened from chewing and biting on them in the patient’s sleep and they stop holding the teeth as tightly and precisely.  Also, these retainers do not allow the teeth to settle into a stable bite like the Hawley retainers are designed to do and therefore these are not recommended for long-term retention, only for temporary or limited wear retention.

 

 

A night guard can also be used as an upper jaw retainer in cases where grinding is a persistent problem; these are fabricated from a thicker plastic or acrylic material providing a surface of material to chew on instead of wear down the teeth.  This should not be used without regular monitoring to record any wear patterns and determine if long-term nightguard wear is necessary and/or beneficial.

 

What affects the need and duration of retainers?

 

Timing of treatment can be an enormous factor in how we retain teeth and for how long.  Cases that are treated during growth and just as teeth are erupted will generally be more stable than a case treated as a late teen or adult.

 

Proper diagnosis is absolutely essential for a stable correction; this is probably the number one reason patients should NEVER seek treatment from in-experienced or untrained doctors and certainly NEVER try Do-It-Yourself remedies to align teeth.

 

An accredited Orthodontist has studied thousands of cases and situations, they understand development better than anyone including General Dentists and Pedodontists.  They are the specialists that can tell not only that there may be an existing problem, but they can tell when there will be a problem, when the potential problem should be treated and what the best method of treatment may be.  A good Orthodontist will not try to tell a patient/parent what they WANT to hear but will focus on what they NEED to hear.

 

 

And a good Orthodontist will not treat a patient to a lower standard without clearly informing the patient and parent that there is a better treatment (i.e. braces v. clear aligners and Invisalign).  General dentists offering orthodontics based on weekend courses will never have the knowledge and experience that a trained orthodontist has; without that knowledge base, underlying problems, developmental discrepancies and even underlying skeletal dysplasias can be mis-diagnosed or missed altogether.  After all, we would have specialists with two to three years of additional training if anyone could diagnose every situation without the knowledge.

 

Proper mechanics play a role in retention as teeth that are fully moved and aligned (parallel to adjacent teeth and in ideal relationship in all three dimensions of space).  There are some movements that cannot be made with removable appliances/Invisalign such as root movements or intrusion of teeth.  When a tooth is left “tipped”, it may appear straight in the mouth but it will relapse due to poor/inadequate/incomplete tooth movement.  This is why Invisalign has a much higher relapse rate versus traditional (real) orthodontics/braces.

 

Degree of movements (and types of movements) plays a big role in retention; teeth that have to be moved farther or rotated to a higher degree will have a higher tendency to relapse no matter the appliance used to move the teeth.

 

Note the roots in the lower arch with canine and 1^st bicuspid roots “kissing” at the apices. This is typical of treatment with removable aligners like Invisalign ad is one reason relapse is more common with clear aligners.

 

 

Of course proper and complete root movement makes for a much more stable correction, we still must retain teeth due to tight collagen fibers providing a memory in the gingiva that pulls teeth back after the correction.  This is why timing of treatment is important; teeth that are “guided” into alignment before they erupt further out of alignment and have to be pulled back into the arch are going to hold better.  Also, teeth corrected while finishing development will hold better when there are severe rotations.  Large segmental movements to correct excessive overjets/overbite or even open bite are best moved in concert with growth to limit tooth movement by making the underlying bone grow closer and more ideally.

 

 

Oral habits play a role in developing malocclusions and relapse following correction.  Tongue thrust for instance will upset the equilibrium and cause the teeth to push outward from muscle forces.  Sleeping with your mouth open will do the opposite by causing the cheek muscles to fold upper teeth inward which constricts the arches and causes crowding.

 

Thumb sucking causes a variety of issues that can be lasting due to hyperactivity of muscles years later that can retard jaw growth and cause over-eruption of back teeth with bite opening in the front of the mouth.  Retention must be designed specifically for the habit to reduce relapse potential and retention may be indefinite in some of these situations.

 

Bone quality/oral hygiene/nutrition also affect how well we can hold a correction following orthodontic treatment. A loss of bone can reduce the resistant a tooth has to natural (or even worse, excessive) muscle forces in the mouth; one time stable teeth may actually start protruding outward due to a lack of bony support holding the teeth following a loss of bone.  This is the same with less dense bone secondary to nutritional deficiencies.

What to expect from a good Orthodontist

 

 

I am not aware of a definite standard of care when it comes to retention other than Orthodontists are required to explain and offer retention after every correction.  How an individual Orthodontist chooses to retain teeth can be a personal preference based on experience, based on ease of the patient to return, based on compliance during treatment, based on desire of the patient and/or parents, and even sometimes based on expense.

 

I personally have a standard protocol for retention that I modify based on the initial malocclusion, the time we treat, and the degree of movement.

 

For early treatment cases early treatment from age 6 to 10 (including expansion with RPE, limited braces to correct crossbites and clear paths for eruption of other teeth) I will place a clear aligner to wear at least 6 months at night.  These can be modified as teeth erupt and replaced cheaply if lost or broken.

 

For adolescents, I place a set of clear aligners immediately after removing braces then a Hawley-type retainer two to three weeks later.  The clear retainer will be worn full time (24h/day) until receiving the Hawley then the clear retainers are dropped to 5 to 6h/day and the Hawleys the remainder of the time to allow teeth to settle.  Eventually (usually at 6mo into retention), I will reduce retainer wear to every night then at another 6mo, assuming good compliance and retention is holding well, I will reduce to 3 nights a week. At the end of retention, at 2 years post-orthodontics, I have patient down to one night per week wearing the Hawley.

 

For adults, retention will always include a clear set of aligners and we will usually follow the adolescent protocol of adding a set of Hawley retainers though in cases of significant movement, we will place a fixed wire in the lower arch (in addition to the clear retainer).

 

In all cases, we follow our finished patients a minimum of two years for all comprehensive cases (adolescents and adults) and we follow all early treatment cases until all permanent teeth are erupted.  I see every patient at every appointment without exception.  I want to make notes on compliance, any movement and adjust wear time accordingly.  I also may find that a particular retainer is not working and I will change the design and/or remake the retainer.  I want to get each patient to the point of minimal retainer wear and educate each patient and parent as to what to look out for, when to expect changes and how to deal with things like latent growth wisdom teeth or future restorations.  After the two years I charge a small fee for further visits based on need.

 

If you have questions or comments concerning this or any orthodontic question, please feel free to make a complimentary new-patient appointment at either my Steiner Ranch location or my North-central Austin location on West 35^th street and MoPac.

Central Austin on 35th Street

 

 

Northwest Austin in Steiner Ranch at Lake Travis

 

Dr. James R. Waters is a 1996 Summa Cum Laude graduate from UTHSC Dental School in San Antonio, 1997 graduate of Advanced Hospital Dentistry from the UNMC in Nebraska and the 2001 Valedictorian graduate from the prestigious Saint Louis University Orthodontic Program receiving the J.P. Marshall award for clinical excellence in 2001.  He holds a Bachelor’s Degree in Science, Doctorate in Dental Surgery, a post-doctorate certificate in Advanced Dentistry, post-doctorate Degree in Orthodontics & Dentofacial Orthopedics and a Master of Science Degree in Orthodontics. He is a Diplomate of the American Board of Orthodontics and member of the College of Diplomates of the ABO.  Dr. Waters has been honored as one of “Texas Best” Orthodontists by his peers in the Texas Monthly magazine focusing on Texas healthcare providers for 14 years straight.  Dr. Waters and his wife of 23 years live in Austin, TX with their 4 children where he has a thriving, multi-faceted Specialist practice with locations in Steiner Ranch and North-Central Austin.  You can learn more about Dr. Waters at www.BracesAustin.com .