The majority of orthodontists advise their patients that YES, in order to prevent your teeth from shifting following an orthodontic correction, removable retainers must be worn nightly for the rest of your life. I may just be the only orthodontist that does subscribe entirely to this philosophy and I will explain why.
Firstly, there are two types of retainers:
1) Fixed or bonded retainers are wires that are glued onto the inside surfaces of usually the upper four and lower six front teeth. The primary purpose of fixed retention is to hold the alignment of front teeth.
2) Removable retainers are retainers that can be taken in and out, and are designed to retain an entire dental arch. Types of removable retainers include traditional “Hawley” type retainers that have a rigid wire that spans mid-tooth across the front surfaces of the teeth, has clasps on molar teeth and supportive acrylic that covers the palate in the case of an upper retainer, or is horseshoe shape in the case of a lower retainer. Clear “Essix/Vivera” retainers are tray-type retainers that have full arch and full tooth coverage. These types of retainers are akin to “Invisalign” trays or bleaching trays. The primary purpose of removable retention is to hold arch width but also tooth alignment, in the absence of fixed retention.
Here’s what we know about teeth; they are not set in cement, they are set in bone. Bone is a dynamic part of our body and continues to change as we age. The teeth most affected by aging are the lower front teeth that have a tendency to collapse inwards towards the tongue and cause crowding. In order to manage these teeth, I place fixed bonded retention from canine to canine in all of my patients to maintain the alignment of these teeth long-term. The upper front teeth change to a lesser degree, but rotations and spacing are at increased risk for relapse. Since these teeth are the most noticeable in the smile, we always want them to be esthetically ideal and therefore I also place fixed bonded retention across the inside surfaces of the upper four incisor teeth. All of my fixed retaining wires are custom-bent in the mouth. I recommend that fixed retaining wires remain in place indefinitely.
I do recommend upper removable retainers but NOT forever. For most of my patients, I recommend that removable retainers be worn full time (24/7) for six months, nights only for six months and three months every other night for three months until they are finally discontinued. If I have diagnosed my cases correctly, planned for them to be stable, followed them closely in retention and weened patients off their removable retainers under my supervision then indefinite removable retention is unnecessary. Teeth rest in a balance between the forces exerted from your tongue on the inside and your lips on the outside, therefore in most scenarios the arch width that patients present with initially is the most stable. If the dental arch is altered dramatically from its original width then an imbalance of forces is created, instability is introduced, and collapse/relapse becomes a certainty.
The reality is that very few of us are motivated to wear a removable retainer indefinitely even if it’s just at night. In my view if an orthodontic correction is not stable long-term than it’s not a successfully treated case. Our office includes 12 retention/follow-up checks for all comprehensive treatments and always has. We have been treating patients orthodontically for almost fifty years and follow our patients for years after the completion of their active treatments so we know this philosophy works!