Small-Diameter Implant Solutions

William C. Martin, DMD, MS, FACP

Any practice utilizing implants to replace missing teeth needs to have a portfolio of implant options for varying clinical situations. When indicated, small-diameter implants will not only allow for more bone volume around the implant, but will also provide enough space for the prosthetic materials, facilitating an esthetic result. In clinical situations involving maxillary lateral incisors, mandibular central and lateral incisors where we find limited inter-root and interdental space, the small-diameter implant is indicated.

There is a patient population that will benefit from these implants: patients with syndromes such as ectodermal dysplasia, microdontia, partial andontia, and in patients with small dental arches and/or limited alveolar growth. In situations where bone grafting is indicated only for esthetic measures, patients can benefit financially by opting for a reduced-diameter implant when restorative contours and occlusal loads are favorable.

At this time, we have a few patients who do not qualify for the 3.5-mm implant because of limited interdental space, and they are waiting for this 2.9-mm implant. Even though the difference in dimension between the two is 0.6 mm, in that space 0.6 mm can make the difference in available bone and restorative volume for an acceptable outcome. This option is going to be well received by this patient base.

The clinical treatment in the accompanying case is nicely documented. They used restoration-driven planning and placement of the implants and followed it with tissue shaping and capture for the technician to create natural-looking restorations.

When I evaluate narrow diameter options, I am looking for an implant that is going to be strong and that will hold up under functional loads and have a prosthetic connection that has good stability for both engaging and non-engaging situations. The number one factor I look for is whether the body of the implant has enough strength to withstand the occlusal forces, along with an implant design that is favorable for these types of anatomic situations.

Another key factor is related to clinical situations with limited inter-root space. You need an implant that is going to allow you to maneuver in these tight spaces, and a tapered implant gives you that advantage. Where there are converging roots in tight spaces or anatomic limitations, tapered implants are indicated. After strength and taper, the third factor I consider is the prosthetic connection. You need an implant that has a prosthetic connection that is not only stable, but also allows enough space for your abutment and restorative material to result in a natural-looking tooth. You need a connection that is internal, because you want room to build your restoration up into the clinical, visible area. For these reasons, we prefer implants that have internal connections as they satisfy these requirements and offer good clinical feedback when seating components in tight spaces. In addition, internal connections can allow for the fabrication of abutments that offer maximal space for restorative material providing the ability to achieve maximum esthetic outcomes.

Our clinical setting provides us the opportunity to consult and treat a wide range of implant patients, including the management of complications. Implants that are reduced in size can elevate the potential for their mishandling or misuse due to the ability to position them in a larger number of clinical situations. It is important for the treating clinician to understand that the small-diameter implant is one component of a large portfolio of implant options that should be carefully chosen based upon the needs of the patient and desire for a long-term functional and esthetic result.

About the Author

William C. Martin, DMD, MS, FACP
Director, Center for Implant Dentistry
Clinical Professor, Department of Oral and Maxillofacial Surgery
University of Florida - College of Dentistry
Gainesville, FL