Mechanical properties of implant position and crown root ratio?

I installed a 5.5×8.5 Nobel Active implant in the #30 site [mandibular right first molar] 7 months after extraction. The bone quality was questionable and the primary stability was 15Ncm. I placed a cover screw, buried the implant, and will return in another 6 months. Because the bone quality was questionable and softer than ideal, I installed the implant in the septum furcation area. The implant has more mesial inclination than ideal. I used a short wide implant because there was only 11mm from the crest of the ridge to the inferior alveolar nerve based on measurements in the CBCT scan. I am concerned that restoring this implant, with its mesial angulation and short length, may lead to difficulties. The crown to implant ratio is unfavorable. What do you recommend?

9 Comments on Mechanical properties of implant position and crown root ratio?

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Dean Licenblat
i wouldn't be worried about the mesial inclination as a custom abutment will correct this. Whilst it's not ideal it's not a catastrophic failure. However I would strongly recommend a sequential bone training regime. Feel free to email me, if you would like my bone training regime. I wouldn't wait 6 months but begin bone training at 3 months. This will work out just fine.
Alex Zavyalov
Good healing. I would proceed with using a custom made abutment and possible occlusion rests from restoration on the adjacent teeth to lower mastication loading.
Not to worry , you are not the first and will not be the last that this happens to when placing into the inter-radicular Bone . It has happened to us all , as for low torque and so called "poor " bone , not to worry by merely placing the Implant into the site you have up-regulated the host healing response and when you load you will you do the same again ( See Sasaki , in JOMI ) , so integration will not be an issue and can be checked with Osstell if concerned . As to length yes maybe a mm or or would have been better , but again we all do that in the new modern more medico-legal world and yes there is lots of evidence to support shorter implants . Peter
First of all - Short implants do work - i suggest to look at this Crown implant ratio - at prosthetic point of view, even if you deal with teeth, you have a protecting teeth - neghbouring teeth, you have like a single tooth restoration. crown implant ratio is not a problem, just deal with lateral forces and you will be okay. also implant surfaces are going to facilitate osseointegration, so about bone training, at biological point of view - if you do not use GBR, you can start bone training after 6 weeks (look at bone healing times in hystology book or something like that) just check for fixed gingiva, because many times i find no fixes gingiva in this region. and i do agree, that if you will be able to screw a transfer, you will be able to fit an abutment, just use custom made.
Thanks for wonderful video link about the short implants.really it was good.
Why do you think the bone was so soft after seven months? Was any grafting done? I occasionally get these little surprises of soft bone in post extraction areas really tough to fix. I might have gone a bit deeper to pick up some of the nascent bone but the soft bone concerns me more than the implant size, hope it heals for you, keep us posted.
I would like to know more about "bone training"
Dean Licenblat
feel free to email me at info AT about bone training
Richard HUghes, DDS, FAAI
I'm not concerned about the angulation of the implant. The laboratory of doctor can prep am angled stock abutment or a custom milled abutment will work nicely. A Quantum or Bicon implant would of been a superior choice in this situation. The Quantum and Bicon short implants will give one the requisite BIC without the risk of injuring the IAN. I strongly suggest one considering them in areas where there is a risk of nerve injury.

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