Donut-Attacks-ToothOver the years I have noticed sometimes after placing and restoring implants—especially on lower posterior areas—that the proximal contacts seemed to open up over time or have an area that allowed for food impaction.

After a recent post on Spear Talk, the discussion forum of Spear Education now available with a free Basic Membership, I found out that I wasn't the only one that has noticed this occurring over time. After reading the thread and a few papers posted on the discussion forum, here's what I learned from two different articles:

  • Somewhere between 34-43 percent, on average, of interproximal contacts will be lost between an implant supported fixed dental restoration and an adjacent tooth; the longer the period of observation (10 years) showed a higher rate (43 percent) of interproximal contact lost

  • Fifty-two percent of the contacts are lost on Mesial vs. 16 percent on the Distal

  • There are more contacts lost on the lower/mandibular arch (49.2 percent) vs. upper arch (31.8 percent)

There are a lot of thoughts or theories as to why this occurs including mesial drifting and interproximal wear over time leading to tooth movement and to the teeth drifting or shifting.

So how do we manage it going forward? Well, there are some thoughts on making some of the implant support restorations retrievable via screw-retention. This way when the contact opens up over time, the restoration can be removed; a proximal contact area is added back and then the restoration is placed back into position.

The bottom line is, when we do an implant support restoration we need to advise our patients that one of the long-term risks is shifting teeth and a space being created between the implant and adjacent tooth.


1. Byun S-J, Heo S-M, Ahn S-G, Chang M. Analysis of proximal contact loss between implant-supported fixed dental prostheses and adjacent teeth in relation to influential factors and effects. A cross-sectional study. Clin. Oral Impl. Res. 00, 2014; 1–6.,3,

2. Koori, Hidehiro; Morimoto, Keizo; Tsukiyama, Yoshihiro; Koyano, Kiyoshi. Statistical Analysis of the Diachronic Loss of Interproximal Contact Between Fixed Implant Prostheses and Adjacent Teeth. International Journal of Prosthodontics . 2010, Vol. 23 Issue 6, p535-540.

Jeff Lineberry, DDS, FAGD, Spear Visiting Faculty, Contributing Author. [ ]


Commenter's Profile Image Larry
May 15th, 2014
The problem exists in the natural dentition too,
Commenter's Profile Image Margo Robinson
May 29th, 2014
I recently attended a lecture where this topic was discussed. The speaker had seen this problem with his implant work over many years of follow up, and now as a result requires each patient he restores with implants to wear an essix retainer to stabilize dentition and prevent drifting. The speaker was big on consent forms and requires all of his implant patients to sign this so that they cannot come back in years to come and complain and expect the work to be redone due to this anticipated problem. Just a suggestion.