Full Arch implant bridges (All-on-4, permanent dentures, etc) are a wonderful thing. They quickly turn around a patient’s self-confidence and get them back on track with their diet and overall health. I have had a very positive experience providing my patients with this treatment.
if done the wrong way, they can lead to pretty disastrous outcomes. Although failure of osseointegration of dental implants does sometimes occur, is not the major complication for these cases. Rather, the nuisance really is managing prosthetic complications. (To learn how you can make All-on-Four Prosthetics & Manage common complications, see our training courses)
Here are some common issues that are encountered with All-on-4 treatments:
Fracture of Temporary All-on-4 Restoration
This fracture occurred months after immediate loading right around the titanium temporary cylinder where the denture was ground-away during the conversion process.
The following is a video of the distal portion of an All-on-4 temp fracturing due to loosening of the angled abutment screw. Once the angled abutments are loose, it is a really big pain in the butt to seat them in the correct orientation!
Many of my colleagues running into complications with their big implant cases. Be fully aware that Fixed implant dentures, All-on4’s, implant bridges (whatever you want to call them) can and will break–especially the temporary set. 🎓Here are some tips to avoid the most common complications I am seeing: 💥Tighten the abutments all the way. Check their tightness every time the bar comes off. 💥 Eliminate occlusion at cantilever…or else 💥Minimize cantilever to reduce lever actions that will loosen or break your screws 💥 Establish level occlusal plane–even if this means delaying the implant case, this will give you a much better result. 💥 Make the framework passive. People often respond “Well technically it can’t be perfectly passive…” Go the extra mile and make it passive. Implantninja.com #implantninja #allonfour #dentalimplant #implantología #implantology #implantesdentales #implantdentistry #dentalimplants #implantdentures #dentistry #dentist #oralsurgery #cirugiaoral #implante #implantes #prosthodontics #prosthodontist #dentist #fullmouthreconstruction #dentallab #lab #labtech #medical #art #prosthetics
Colleagues always ask me about how to manage this. Here are some of the ways that I have minimized this occurrence in my practice:
- Occlusion! Make sure you have even occlusal contacts with group function. This means making sure they have a good opposing arch.
- Ensure you are leaving enough acrylic thickness to withstand all the chewing ability you just gave back to your patient.
- Make a vacuuform splint that the patient can use as a temporary night guard.
Insufficient Inter-Arch Space
This is a classic case of inappropriate planning. Implants were placed without reguard for how much inter-arch space was necessary and it led to the demise of the acrylic hybrid.
Do yourself a favor, before jumping into a placing implants, take a moment to make sure there is enough restorative space. I say 12mm for acrylic, 15mm for zirconia–PER ARCH. You can measure their existing denture, or you can actually do a full wax set-up (gasp!) when evaluating the case. This extra work spent planning will pay off considerably!
Inadequate Support at Cantilever
In this case, the cantilever fractured clean off:
Remember, you should always remove all occlusion at the posterior cantilever. In this case, you can see that the titanium bar did not extend distally past the last implant. In addition, the bar appears polished and smooth–reducing any mechanical retention of the acrylic. These design flaws makes the cantilever of the prosthesis highly prone to fracture.
Severe Angulation Prohibits Seating of Titanium Bar
Anyone who has placed an implant knows how it feels when after implants are inserted, you wish your angulation was a little different. All-on-4 appointments are long and by the time the whole surgery is done and all those tiny abutments and screws are painstakingly put on, the last thing you want to see is a severely deviant angulation.
While, All-on-4 prosthetics are a little more forgiving in this regard–severely deviant angulations willl make it impossible for your framework to passively fit onto each abutment. Luckily some implant companies not only sell different angulations of abutments, but also different angled abutments with different rotational relationships to the implant.
Invest in learning to manage “Oh Crap” Moments
When I go to meetings, I am often surprised by how many people say they are ‘doing’ All-on-4 cases. My practice is completely limited to these types of larger implant rehabilitations so I am rather proficient at this stuff by now– but I still run into issues sometimes.
My advice to someone who is looking to incorporate these treatments into their practice, is to look for a CE course that will teach you to manage complications of Full-Arch Implant Complications. This would be priceless. I don’t know of any that I can recommend, but you can bet that I will be developing one of these courses and begin offering it in 2017. (Update: We are now offering an online training course called All-on-Four “In a Box”. We teach how to make All-on-Four prosthetics and how to manage complications.)
This complications list is far from comprehensive. I’ll be posting some additional pictures and complications in Part 2 of this Article.
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