An eposteal implant is a type of dental implant that sits on top of the jawbone rather than inside it. The term “eposteal” literally means “on the bone,” and these implants are more commonly called subperiosteal implants. They consist of a custom metal framework that rests on the surface of the jaw, beneath the gum tissue but above the bone itself. Posts extend through the gums to anchor replacement teeth. They exist primarily for people whose jawbones have deteriorated too much to support conventional screw-type implants.
How Eposteal Implants Differ From Standard Implants
The implants most people think of when they hear “dental implant” are endosteal implants, meaning “in the bone.” A surgeon drills into the jawbone and inserts a titanium screw that acts as an artificial tooth root. Over several months, the bone fuses around that screw in a process called osseointegration, creating a very secure anchor.
Eposteal implants take the opposite approach. Instead of drilling into bone, the surgeon places a metal framework directly on top of the jawbone’s surface, tucked beneath the thin membrane (the periosteum) that covers the bone. The framework is held in place by the overlying gum tissue, which heals around it and locks it to the jaw. Posts protrude through the gums, and dentures or bridges attach to those posts. Because there’s no drilling into bone, the procedure causes less disruption to the jaw itself.
Structure of the Framework
An eposteal implant framework has three main components: primary struts, secondary struts, and transmucosal abutment posts (the parts that poke through the gums). The struts form a lattice-like grid designed to sit against the densest areas of cortical bone on the jaw’s surface, particularly along prominent bony ridges where lateral movement is minimized. The lattice design isn’t just structural. It’s intentionally open so that the gum tissue can reattach to the bone through the gaps, which helps anchor the whole implant and reduces the risk of the overlying tissue wearing away.
The framework needs to sit on dense outer bone because the top of a severely resorbed jawbone is often soft, cancellous bone that won’t provide reliable support. Designers position the struts against the strongest anatomical landmarks available.
Who Needs an Eposteal Implant
These implants are specifically designed for people with severe jawbone loss, typically patients classified as Cawood and Howell Class V or VI (the most advanced categories of jaw resorption). At that level of bone loss, the remaining ridge of jawbone is too narrow or too shallow to accept a conventional screw implant without additional procedures.
Eposteal implants are the only technique that allows rehabilitation of a very narrow bone crest without sacrificing any remaining vertical height. Bone grafting is the other option for severe atrophy, but it adds months of healing time and additional surgery. In published case series, patients receiving these implants ranged from 27 to 69 years old, and all had bone atrophy severe enough that standard implants were ruled out. They were predominantly people who had lost all or most of their teeth and had experienced years of progressive bone shrinkage beneath their dentures.
Materials Used
Historically, eposteal frameworks were cast from cobalt-chromium-molybdenum alloys. These are strong and corrosion-resistant but not ideal for long-term tissue compatibility. Modern versions use titanium alloy, the same grade (Ti-6Al-4V) used in hip replacements and other orthopedic hardware. Titanium offers better biocompatibility, meaning the surrounding tissues tolerate it with less inflammation, and it’s lighter, which matters especially for upper jaw implants where a heavier framework can erode the overlying gum tissue over time.
How 3D Printing Changed the Process
The old method of fitting an eposteal implant required two separate surgeries. In the first, the surgeon opened the gum tissue and took a physical impression of the bone surface using impression material. That impression was sent to a lab where the framework was cast. Weeks later, the patient returned for a second surgery to place the finished implant. This doubled the trauma, extended treatment timelines, and introduced the risk that the framework wouldn’t fit perfectly due to shrinkage in the impression material.
Modern eposteal implants are designed entirely on a computer. A cone-beam CT scan captures detailed three-dimensional images of the patient’s jaw. Using CAD software, clinicians virtually plan the implant placement, accounting for bone density, nearby nerves, and the position of remaining anatomical structures. The framework is then fabricated through direct metal laser sintering, a type of 3D printing that builds the titanium structure layer by layer from digital data. The result is a single surgery instead of two, a more precise fit, less tissue trauma, and the ability to preview the treatment outcome digitally before cutting anything.
Recovery Timeline
Because eposteal implants don’t require drilling into the jawbone, the healing period is generally shorter than for conventional implants. Recovery typically takes several weeks to a few months, compared to the three to six months of osseointegration time that endosteal implants require. During the first week, you’ll eat soft foods like soups, yogurt, and mashed potatoes to avoid disturbing the surgical site. Over the next few weeks, you can gradually reintroduce firmer foods, avoiding anything sticky or very hard for the first month. Once the gums have fully healed around the framework, the metal becomes firmly fixed to the jawbone and prosthetic teeth can be attached to the posts.
Success Rates and Longevity
Short-term outcomes for modern eposteal implants are encouraging. A Kaplan-Meier analysis of contemporary cases found a 97.5% survival rate and 91.6% success rate at two years. Over longer follow-up (averaging 8.9 years), survival remained at 89.4%, though the success rate dropped to 53.9%. That gap between “survival” and “success” reflects the difference between an implant that’s still in place versus one that’s functioning without any complications. Many implants that experienced problems were still salvageable and remained in the jaw.
These numbers should be understood in context: eposteal implants are placed in the most difficult cases, in patients whose bone was too compromised for any other implant option. Comparing them directly to the 95%+ success rates of conventional implants isn’t quite fair, since the patient populations are fundamentally different.
Common Complications
The most frequent problem after eposteal implant placement is soft tissue dehiscence, where the gum tissue pulls back or breaks down and exposes part of the metal framework underneath. Published exposure rates range from about 24% to 38% depending on the study, and overall biological complication rates (including infection and tissue inflammation) range from roughly 6% to 44%. The wide spread reflects differences in implant design, material, surgical technique, and patient health.
Exposure of the framework doesn’t always mean the implant has failed. In many cases, the exposed area can be managed or the tissue can heal. But persistent exposure increases the risk of infection around the implant, which can eventually lead to implant loss if it progresses. The lattice design of modern frameworks, which encourages tissue to grow through the gaps and reattach to bone, is partly an engineering response to this problem. Lighter titanium frameworks also reduce the mechanical pressure on overlying gum tissue that contributes to dehiscence.