I have recently seen online a video introduction by a well-known British orthodontist to attend his upcoming lecture on retention. And this forced me to write this post.
This is true that British researchers have been very active in the recent years carrying out studies on retention. But I can’t help feeling that the question researches always ask in such studies is absolutely wrong. It often sounds like this: which type of retention is better?
In my opinion, a type of retainer or how it is worn has almost NOTHING to do with the problem of retention. I am going to write my post about what I consider important for stability. This is very subjective view which I base on my clinical experience and my critical evaluation of the long-term records from different sources.
Here are three major factors I believe are critically important for stability:
1. Keeping initial arch form
Keeping initial arch form is your best retainer. This is the form being dictated by the surrounding soft tissues and once you have expanded it, there will be a collapse. I believe in uprighting. But I don’t trust expansion.
2. IMPA
Incisor mandibular plane angle is critical when we want to avoid the crowding of the lower front teeth. Once you procline, be ready to rely heavily on a fixed 3-to-3 for life. It’s also prudent to fix this type of retainer on each patient because what we know for sure – this region moves! In general, more proclination, more relapsation…
3. Interdigitation
This is very clear. The tighter the contacts are the better this keeps the teeth stable… and from this perspective Hawley retainers are obviously better.
Again, this is my personal opinion based on my own experience, on what I saw in many lectures, and on what I was able to elicit evaluating study models of several senior colleagues.
Of course, many other aspects may also come into play, such as initial malocclusion, tongue thrust, periodontal issues, etc. But these three factors above are the keys I look at to prevent a relapse.
Overall, I think it is hardly possible to unequivocally evaluate the best retainer scientifically. Retention is not about a retainer. It is about a quality of the work being done for 2 years prior you place a retainer.
Dear Dr.
Although I agree with most of your opinions, you don’t take in consideration the existence of transeptal fibres, than can produce relapse. The interdigitation is important, but most of the time the teeth are not in contact and those fibres can move the teeth from the final position. Thanks fot your article.
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Hi Diego, thanks for your comment, there are certainly other factors I haven’t mentioned. I focused on three most important from my perspective. Just to keep it brief.
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Retention is affected by occlusal features, patient health and habits. In addition to occlusal features you have mentioned, long-term stability is affected by whether the teeth are placed within alveolar bone-the neutral zone. In addition to transseptal fibers, the health of periodontium is key. From patients perspective, they should maintain good oral hygiene and avoid parafuntional habits.
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Great article and I agree with your premises. I just wish that I could get my patient to wear their retainers 5 nights/week! Anecdotally, I would guess that I have about 25% compliance. So much hard work to fall flat because the patient doesn’t value the care.
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[…] 5. Retention has nothing to do with a retainer. A very personal opinion […]
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