16 years ago a landmark study by Tarnow taught us a critical principal of implant dentistry.
Tarnow is an oft-cited authority on dental implants and this article is a big reason for that. Several of the fundamental principles that we all use in determining implant placement is from Dr. Tarnow’s work. This article from the Journal of Periodontology in 2000 will teach us how to space dental implants.
In this study the researchers divide patients into 2 groups:
1. implants closer than 3mm to each other
2. implants farther than 3mm
They then measured on a radiograph from the implant to the crest of the ridge laterally.
Implants that were closer than 3mm together had crestal bone loss of 1.04mm, while the crestal bone loss of implants further than 3mm was .45mm.
The clinical significance of this is that a full papilla will not develop or be maintained without adequate bony support.
The article also points out that it is harder to maintain interdental bone/papilla between 2 implants than between a tooth and an implant.
This is likely due to the lack of PDL and thus blood supply to the crestal bundle bone.
Also mentioned in the article is another principal reported by Tarnow from another study stating that papilla is preserved 100% when the contact point is 5mm or less from the crest of bone. We’ll review that one soon…
Take home message:
- Keep implants at least 3mm apart from each other
- To preserve papilla in the anterior, narrower implants in favor of greater inter-implant bone should be considered.
- The crown contact point should be at 4 to 5mm from the crest of interdental bone.
