Are 5.5+mm implants needed?

I heard some colleagues say there is not much benefit in placing large diameter implants (Φ5.5mm or even larger) even if the bone is adequate?
What are your thoughts?

Tim Carter comments:

I believe that it is a preference of some to place these large diameter fixtures but I do not believe that one is ever restoratively necessary. I personally never place anything larger than a 4.7 Zimmer TSVM and keep a couple of 5.7 in stock for the rare occasion that I can't get stability on a 4.7. If we look back at Straumann, one of the most successful products on the market, their original tissue level fixture only goes to 4.8 diameter. The early studies back when 3i introduced the 6.0 suggested that this larger diameter was potentially like killing a fly with a hammer.

MC Hammer comments:

Sometimes I wish that I could kill a fly with a hammer!

Dr Kambiz comments:

There is no need for larger than ca 4mm(D)x10mm(L) implants, unless the extraction site dictates it.

ron receveur comments:

A few years ago I went to the manufacturing facility for Neodent in Curitiba Brazil. I spent time at Ilapeo (sic) clinic watching the Brazilian doctors provide indigent care. I was very surprised at how small the implants were that they were placing. "Bigger was not better for them". I learned a ton on that trip. Their philosophy wasn't bigger is better, rather it was important to them that there was a lot of vascularity / blood supply around the implant. In other words, they didn't want their implant "bigger" if it meant that the implant was up against the cortical wall where there was no blood supply.

Greg Kammeyer, DDS, MS comments:

I respectfully disagree with the view that 4mm implants are adequate. A number of studies show the crestal 1/3 of the implant takes most of the force, so diameter matters. For a molar I want a 5 or a 6mm implant. This allows me to do more immediate placements as well as I have virtually eliminated complaints about interproximal food collection. I have 7, 8 & 9mm implants too. They carry challenges of thin buccal plates and I use them rarely.

Tim Carter comments:

Dr. Kammeyer,

You seem like a reasonable individual and one that I am comfortable asking this question. What about a wide diameter fixture allows it to be more suitable for immediate placement in a molar site? I have been placing immediate implants in molar sites for over 15 years now and have never found a situation where a fixture greater than 5mm was necessary. I have seen these wide diameter products out there and read the promotions but still I can’t seem to make sense of it from a biological perspective. We speak all the time about the need for >2mm bone around a fixture for vascularity and I believe we can all appreciate the importance of such. When placing a molar immediate I would much rather graft the “jumping space” around the fixture with some product that is likely to be replaced with vascular bone rather than obturate the space with inert titanium. In addition I have noticed that the majority of these wide fixtures have normal (3.5-4.5mm) internal connections so now we are back to a regular platform restorative space. As far as primary stability that can easily be achieved by engaging the apical 1/3 of the root space with a standard diameter fixture. Finally in the unfortunate event that a fixture fails I think it would be a much bigger problem if a 7-9mm diameter failed over a 4-5mm.

surfperience comments:

Nice to meet you. I would urge you to also consider the prosthetic requirements, such as the crown-implant ratio, the proximal and distal width diameters of the prosthesis, and how many more years the patient will use this implant when considering metal fatigue. What about occlusal forces, malocclusion habits, the condition of the opposing teeth, and the degree of tooth mobility of the remaining teeth?

The strength of the implants also depends on whether they are external or internal connections, the design of the abutment joint, and whether the implant material is titanium alloy or pure titanium, making it difficult to make a simple statement.

I am a technician and have been working with implants for almost 30 years, and if I were 40 years old and had enough bone width in my molars, I would want a 5.0mm placement.

I have worked for three implant manufacturers and have seen many cases of implant necks breaking due to unreasonable prosthetic design.

Best of luck to you.

Bro Mike comments:

From the technician's perspective, is it relatively easier to make better emergence profile if using wider implant?

Prosdoc comments:

Wide diameter implants are absolutely needed, just like we need 3mm implants. Are they our work horse implant? Of course not. They are a specialty implant used in large molar areas only, if the bone is adequate. There's been surgical discussions but not much said about the restorative concerns. Our lab colleague was the most on target. In larger spaces the M-D cantilever off a regular sized implant can place undue stress on the lip of the implant and the implant/abutment interface. We've all talked about the tomato on a stick look when the implant diameter doesn't come close to the crown size. So, yes, wider diameter implants should be part of our implant arsenal and not be trivialized

Elie Warde DDS comments:

Regular diameter platform implant is the best. 1.5 to 2 mm horizontal thickness of bone. More cervical bone is much better than more titanium

Greg Kammeyer, DDS, MS comments:

Hey Tim, I respect your posts as well. I work as you do with the diameter, 2mm of buccal bone issue. The wider the platform the less micro motion at the abutment/implant interface. This is a strong positive, regardless of immediate placement or not as that microgap harbors bacteria which get pumped in an out during function/parafunction. I also find virtually no complaints with food collection in the gingival embrasure, since the abutment is much closer to normal size. I'm a little behind you with immediate molars, placing them 11 years. Sure I can get a smaller diameter to work, as you can. The short bigger diameter implants keeps me away from a secondary IAN, if there is one and out of the sinus. I'm no stranger to trying a variety, yet I HATE the small bits of food that collect around my own anterior implant, so I don't want others to have the same problem. I also want that extra surface area of bone to implant contact.