Mini implants, also called narrow diameter implants, appear to be becoming increasingly popular as consumers search for faster and cheaper ways to replace missing teeth, and clinicians and implant companies seek to meet that demand. Personally, partly because I am a Carl Misch disciple, I’ve always been biased against implants which appear to be exempt from some of the significant requirements (ie. Osseointegration) of traditional implant dentistry. This bias aides in formulating my belief that mini implants likely work well for their originally intended purpose(s), but there appears to be a growing trend toward off label use. I am relatively uneducated on the of subject mini-implants, but because it appears most of the education seems to be coming exclusively from companies manufacturing dental implants, I’m not sure I would be blessed with so much more education after spending a weekend with MDI.
My personal experience with mini’s is limited to a patient I examined who had a mini placed to restore a missing upper bicuspid with a permanent crown. The mini implant itself, which was approximately one year post-op, appeared stable, free of pathology and with satisfactory bone support. However, the patient came to me with the complaint of food impaction around the implant. Food impaction around implants can be a concern with wider bodied root-form implants, so it comes as no surprise the transition from a one-piece narrow diameter implant to a permanent crown results in a ledge (food trap).
Yet when I am making a lower implant overdenture with two root form implants and the patient is 70+ years old, four months of healing seems like an eternity. Mini implants definitely have a place in my practice, and it appears it is about time we slowly introduce them. A few of the thoughts Carl Misch opined in his Misch Institute lectures on the topic of mini implants, I now come to question now. Years ago I left Misch’s courses with the basic mindset: root form implants=good, mini implant=bad. Dental Implants are dental implants and there is significant overlap between the sizes and techniques for both skinny and fat implants. For example, I’ve certainly replaced many incisiors with Biohorizon’s tapered internal LaserLok implant, I love that implant. Yet, I could almost use a 2mm or 2.5mm diameter implant for some lower incisors. In narrow ridges I’ve also used those same Biohorizon 3.0’s for overdentures. But I tell people I’ve never placed a mini implant…..
Dental implants are technically further classified: implants with diameters smaller than or equal to 2.7 mm are called mini diameter implants (MDI’s), while those of 3 to 3.3 mm diameter are called small diameter implants (SDI’s), and conventional implants are those up to 7 mm. While mini diameter implants are placed by implantologists every day, the treatment protocol usually varies from that advocated by MDI. In other words, MDI’s are almost always placed with a tissue punch without surgically laying a flap and are almost always immediately loaded with the permanent restoration. In traditional implantology, implants may immediately be restored with a temporary restoration, may be loaded in stages incrementally, but are usually restored following the “required 4-6 months” of osseointegration time.
Most published studies show survival rates of over 90%, comparable to those of conventional implants. One such study mentioned there was a higher success rate with mini’s involved with fixed versus removable prosthodontics. But these studies all appear to fall short. Again, implants are implants, MDI is just a company, and this profession needs to do a better job educating dentists in the proper treatment protocols for all dental implants. Nearly all these studies are paid for by dental implant manufacturing companies, so all study results need to be interpreted with this understanding. It was typically these studies which led to the FDA’s approval of long term use of mini- and small diameter mini implants in 1997.
The problem, as I see it, is many dentists who place a large number of root form implants refuse to accept the mini’s place in dentists’ armamentarium for implantology, while those who choose to spend a weekend learning to place mini’s, fail to undertake the training necessary to offer the full spectrum of appropriate treatments. Treatment options will always vary amongst practitioners, but it is this practitioner’s opinion that more uniformity in the treatment planning of those partially edentulous and edentulous patients who seek out dental implants, would not be such a bad thing.