Bone loss with screwed in prosthesis?

Last Updated: Mar 15, 2017

I am posting this case, after reading a previous case on Rapid Bone Loss after re-cementation. In this case, I placed 3 implants in Sept 2015. Restored them after 8 months. 24 cemented crown . 25, 26 were screwed in . At the checkup appointment on March 2017, the x-ray shows nice bone loss at the screwed in prosthesis. Can’t blame the cement here. Could it be lack of passive fit? Could it be occlusion? What are your thoughts?

22 Comments on Bone loss with screwed in prosthesis?

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rsdds

03/15/2017

you may want to take another xray or adjust brightness to rule out distortion..

yosef k

03/15/2017

nice thought but its not the xrays

Dr Jim Amstadt

03/15/2017

I have more questions before I make An educated guess. First was there attached tissue all around the neck of the molar? Also did the implant look centered over the ridge and did you have a cone beam of the molar implant to check if it had a buccal plate of bone? Also when you screwed it down did it screw down easily and hit a dead stop without it squeaking or feeling resistance to finger tightening? Dr Jim

Daniel P. Camm

03/21/2017

It looks like the posterior implant is a Nobel Active implant, which has a conical connection with a platform switch. For years, I had used Zimmer Tapered Screw-Vent implants which have an internal connection and a flush fit with the implant. I rarely saw bone loss on these. When I started doing All-on-4's in 2007, I switched systems for all implant cases to the Nobel Active. I started noticing that a higher percentage of my cases began to show bone loss. I attributed it to something with the implant, but I did not read anything in the literature about anyone else having this problem. I could not explain it, but it made me concerned about the platform switch and/or the implant. Three years ago, I started using only Implant Direct Legacy 2 implants, which have the same connection as the Zimmer TSV implants. I have not noticed nearly the same bone loss as I did with the Nobel Active implants. I know this is not literature-supported, but consider the failure being caused by the implant. I wonder if anyone else has noticed this trend. I do about 180 implants a year, so when a problem shows up like this, I really notice it. Another thought: your other two implants look different than the posterior one. They look like they have flush connections. No bone loss on the more anterior one, and the bone loss on the middle one is on the distal side, adjacent to the posterior implant. Hmmm........

Rand

03/21/2017

I would check the occlusion. Excessive forces always result in bone loss. If the patient is a smoker or diabetic, that could also make them predisposed to failure. What was the cause of the loss of the natural teeth?

Rand

03/22/2017

Eur J Oral Implantol. 2012;5 Suppl:S91-103. Identifying occlusal overload and how to deal with it to avoid marginal bone loss around implants. Fu JH1, Hsu YT, Wang HL. Author information Abstract BACKGROUND: Occlusal overloading is the primary cause of biomechanical implant complications, which include fracture and/or loosening of the implant fixture and/or prosthetic components. It may also disrupt the intricate bond between the implant surface and bone, leading to peri-implant bone loss and eventual implant failure. PURPOSE: This paper was aimed at identifying and evaluating clinical and radiographic parameters relevant for diagnosing occlusal overloading of oral implants. It also discusses its management in order to prevent peri-implant marginal bone loss. MATERIALS AND METHODS: An electronic literature search for relevant studies, examining the relationship between occlusal overloading and peri-implant bone loss, was conducted in the PubMed database. Clinical human studies published in English with a minimum of 10 implants were included. RESULTS: Seven articles were identified. Occlusal overloading was found to be positively associated with peri-implant marginal bone loss. CONCLUSION: Preventing occlusal overloading involves conducting comprehensive examinations, treatment planning, precise surgical and prosthetic treatment executions, and regular maintenance. If occlusal overloading occurs, management of biomechanical implant complications and preventing/treating peri-implant bone loss involves surgical and prosthetic treatment modalities. They include occlusal treatment, repair and replacement of defective prosthetic components, and surgical treatment of the bony craters.

Frank S

03/22/2017

Where is there Any Literature that supports bone loss due to Occlusion? People say this all the time, but Ive yet to read even one grade A level 1 study that supports this assumption.

Frank S

03/23/2017

"It may also disrupt the intricate bond between the implant surface and bone, leading to peri-implant bone loss and eventual implant failure." Respectfully, this is a theory that many have proposed, but no science to date has backed up. Occlusal overload can break things. Porcelain, screws, and even implants, yet bone loss hasn't been shown, once the implant has integrated. FS

Rand

03/23/2017

I have a patient who had an implant to replace an upper first molar. It integrated. It withstood 35 NCM's or torque. After placing the crown the patient returned a month later with the implant in his hand. His favorite snack was "Corn Nuts," a very hard snack. No porcelain, metal or screw broke. It was due only to excessive forces. There is a stress / repair relationship in bone physiology. What happens when stress exceeds the physiologic repair abilities of a patient? The difference between a repair man and a doctor is a great underlining understanding of science and theory to the benefit of his patients. I would recommend reviewing the chapter on Stress Factors in "Dental Implant Prosthetics" by Carl Misch.

Frank S

03/23/2017

I would love to see a grade 1 A study, that specifically tested overloading. There are several experts that challenge this theory. I'd be open to learning and changing my mind, given the science. I don't advocate overloading an implant restoration, but I think those who quickly say that that's the cause of bone loss around an implant, are doing so without science to back that up. Many people say that overloading is the cause of bone loss around a fully integrated implant, I just would love to see the science. FS

Frank S

03/23/2017

Hello Rand, I actually had the Immense pleasure of having a personal conversation with Carl on this subject. He will always be a Giant, if not the Biggest Giant and influence on Implant Dentistry. He did strongly believe what you are saying, but did not have the specific double blind study or literature to support this. This was at least 10 years ago, and I'm not saying it isn't possible, but that there isn't irrefutable proof or studies to back it up. Things break when overloaded, but I'm dubious about bone loss from overloading, once the implant is fully integrated. FS

mpedds

03/23/2017

This is anecdotal, but I am seeing an inordinate amount of failures of Nobel Active fixtures. This implant has a very aggressive thread design that gives you a lot of "high frictional" torque values. I believe these are often loaded prematurely. Remember, just because you have high torque values on insertion (due to friction as in a screw in wood) this has nothing to do with true osseo-integration. Beware.

yosef k

03/26/2017

It was an Alpha bio SPI 5 x10 placed at lowish torque of 25 buried for 6 months plus

James

03/26/2017

My guess Yosef is that it was probably never osseo integrated even though it looked like it was. I doubt that the occ had much to do with it in that very short period of time and also that it sat there for 6 months before loading. I would think by then the bone connect should have been pretty darn good.

Frank S

03/26/2017

I agree James. We put severely angled zygomatic implants with heavy loads, Tads for ortho, regular implants for ortho anchorage, all without bone loss.

yosef k

03/26/2017

James I appreciate your comment . but not integrated ? the screws are torqued at 25 to 30 ncm it was integrated

Jim Amstadt

03/26/2017

Unfortunately, It is very possible to uncover and restore an implant without realizing that it is not integrated in bone. I see Frank agrees too. The implant you are using is very aggressively threaded and it may have appeared stable when it was not. I definitely have seen impressions taken and restorations created only to discover that the implant is no good just as the implant restoration is placed. Dr Jim Amstadt PS. Sorry

Jim Amstadt

03/26/2017

Just another thought Yosef. Just because the case was seated with a torque of 25 to 30 ncm does not mean it integrated. I often place implants with more torque then that but that doesn't mean they are integrated!!!!!! Dr Jim

Frank S

03/26/2017

Ive been taught that the most reliable way to tell if an implant is integrated, is to do a reverse torque test. Clockwise torque can fool you, since it's driving the threads into a bony stop. respectfully, just my thoughts.

Dr James Amstadt

03/26/2017

I would agree with Frank.

Rand Ollerton

03/26/2017

It would seem that integration is not in doubt. There is no mobility, only bone loss. If they were not integrated, there would be mobility and the initial question would not have been about bone loss.

Frank S

03/26/2017

Rand, I agree with your last comment. My last comment was spcecifcally for Yosef. Sorry to cloud the discussion. Back to the original case and question. I'm still questioning that occlusion, or inappropriate occlusion caused the bone loss. Again, I'm open to being wrong, but the common response to bone loss around a previously integrated implant, Ive yet to see evidence supported studies. Frank

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