Global Health Nexus, Winter 2003
Raising the Bar on Aesthetic Dental Implants
The aesthetics of implant-supported restorations have been a focus of interest for the Ashman Department of Implant Dentistry for many years. The original work done by our group and published in 1992 focused on the presence or absence of the interdental papilla. In that seminal study, we found that the papilla was present 100 percent of the time when the distance from the base of the contact point to the crest of bone was 5 mm’s or less. When the distance was 6 mm’s, only one mm more, the papilla was present only 55 percent of the time. When the distance was 7 mm’s, the papilla was present 25 percent of the time, and when it was 8 mm’s, it was present only 10 percent of the time. Since its publication, this paper has helped clinicians determine how to construct restorations in the aesthetic zone between teeth.
We next focused on what happens to the papilla when an implant is placed next to a tooth. The question was whether or not the 5-mm rule would hold up. In collaboration with a group of Belgian researchers, we demonstrated that the same 5-mm rule was in fact also true when an implant was placed next to a tooth. This explains why single-tooth replacements supported on implants can look aesthetically normal, including in the papilla area, and, since normal anatomy can be expected around the final restoration, why most lecturers like to show single-tooth implant patients.
The single most difficult problem facing clinicians occurs when two implants are to be placed next to each other in the aesthetic zone. If the other teeth have normal papillae heights, it becomes a challenge for the clinician to re-form the papilla between these two implants. In fact, it rarely fills in to the original level that existed before the natural teeth were extracted. Accordingly, our faculty began to investigate the amount of tissue that could be expected to cover the inter-implant bone—the area within which most clinicians find it difficult, if not impossible, to get a papilla to look normal. Our findings, which have recently been submitted for publication, show that only about 3 mm of papilla height can be expected between two adjacent implants in the aesthetic zone. Indeed, almost 90 percent of the papilla heights were only 2 mm, 3 mm, or 4 mm. Virtually none of the papillae reach the 5-mm or 6-mm distance that we normally see between two teeth. This means that normal, beautiful aesthetics can be expected when a single tooth implant is placed next to periodontally healthy teeth. However, if two implants are placed adjacent to each other in the aesthetic zone, the papilla will tend to be about 2 mm’s shorter than the papilla between the natural teeth in the same area.
Based on this knowledge, we revised our treatment plan to no longer place two implants next to each other in patients with high smile lines. Instead, we now recommend that one implant, along with an ovate pontic, be utilized in such cases. If three teeth are missing, then only two implants should be placed along with an ovate pontic between them.
In other research, our faculty have shown that wide body implants cause more recession than normal diameter implants. This is clinically significant because it suggests that wide body implants may not be indicated for use in the aesthetic zone. Once again, our findings have changed the way practitioners develop treatment plans when beautiful, normal contoured restorations are the goal in the aesthetic zone.
It is a point of pride that the Ashman Department of Implant Dentistry is an international leader in the field, and that it has made substantial progress in the area of aesthetics with implant support restorations. Currently we are working on a new implant design that will help maintain papilla height in the aesthetic zone. This project is spearheaded by Dr. Nicholas Elian, Assistant Professor of Implant Dentistry. Dr. Elian has a patent pending for an implant top that is scalloped instead of flat. All implants today are straight across at the abutment implant interface. If the implant is placed properly for mid-buccal aesthetics it will cause a violation of the inter-implant bone, which helps support the papilla. Violation of this point is a major factor in bone loss between two adjacent implants. The new, scalloped design will allow the implant to be placed supracrestally in the aesthetic zone, an approach that promises important patient benefits.