A dental crown connects to an implant through a small connector piece called an abutment, which sits between the implant post embedded in your jawbone and the visible crown on top. The crown is then either screwed directly through the abutment into the implant or cemented onto the abutment with a thin layer of dental adhesive. These are the two main attachment methods, and each works differently.
The Three-Part System
What looks like a single tooth is actually three separate components stacked together. The implant itself is a titanium or zirconia post that your dentist surgically places into your jawbone. Over several months, bone grows around and fuses with this post in a process called osseointegration, creating a stable anchor.
Once the implant is solidly integrated, an abutment is attached to it. This is a small connector piece that rises above your gumline and gives the crown something to hold onto. Think of the implant as a foundation, the abutment as a post sticking up from it, and the crown as a cap that fits over the post. The abutment is secured to the implant with a tiny screw tightened to a precise force, typically around 25 to 35 Newton-centimeters, using a calibrated torque wrench. That controlled tightening prevents the connection from loosening under the repeated stress of chewing.
Screw-Retained Crowns
With this method, the crown and abutment often arrive from the dental lab as a single fused piece. Your dentist places the assembly onto the implant and threads a small screw down through a narrow channel that runs vertically through the crown and abutment, locking everything into the implant below. The screw is tightened to a specific torque value with a calibrated wrench, then a small cotton plug is placed into the screw access hole to protect the screw head. The remaining space is filled with composite resin, a tooth-colored filling material that blends in with the rest of the crown.
The access hole is usually positioned on the biting surface or the tongue-facing side of the crown, where it’s least visible. Once filled, it’s nearly undetectable. The key advantage here is that if the crown ever needs to come off for maintenance or repair, your dentist can drill out the composite plug, unscrew the crown, and remove it without damaging anything.
Cement-Retained Crowns
This approach works more like a traditional crown on a natural tooth. The abutment is first screwed into the implant as a separate piece. Then a custom-made crown is fabricated to fit precisely over that abutment. At the delivery appointment, your dentist applies a thin layer of dental cement to the inside of the crown and presses it down over the abutment. The cement layer between the abutment and crown is remarkably thin, roughly equivalent to two coats of nail polish. That’s only about 3% of the crown’s total internal volume.
Cement placement requires precision. The adhesive is applied near the crown margin but not right at the edge. As the crown slides into position, the cement flows upward toward the biting surface, then back down toward the margins, with any excess squeezing out at the bottom. Your dentist carefully cleans away all excess cement from around the gumline. Some dentists do a trial cementation on a duplicate abutment outside the mouth first, which makes cleanup easier and helps verify the fit before the final bond.
Why Excess Cement Matters
The biggest risk unique to cement-retained crowns is leftover adhesive trapped beneath the gumline. Because the connection between abutment and crown sits at or below gum level, cement can seep into the narrow pocket between the implant and surrounding tissue. A systematic review of over 1,000 cemented implant restorations found that the prevalence of gum and bone disease around implants ranged from about 2% to 75%, with excess cement involved in 33% to 100% of those cases. That’s a wide range, but the pattern is consistent: residual cement creates a surface where bacteria colonize, triggering inflammation that can progress to bone loss around the implant.
This risk is higher when cement is placed before the surrounding soft tissue has fully healed, particularly within the first four weeks. To reduce this risk, dentists typically position the crown margin at or near the gumline where they can see and clean it, rather than burying it deep below the tissue.
Screw-Retained vs. Cement-Retained
Both methods produce crowns that look and function the same once in place, and both can achieve equally good cosmetic results when the implant is well-positioned. The differences show up in maintenance and long-term complications.
- Retrievability: Screw-retained crowns can be predictably removed and replaced without damage. Cement-retained crowns sometimes break during removal, requiring a new crown to be fabricated.
- Biological complications: Screw-retained crowns carry lower rates of gum inflammation and peri-implant bone loss, largely because there’s no cement residue to irritate surrounding tissue.
- Technical complications: The most common issue with screw-retained crowns is screw loosening over time, which requires a quick retightening appointment. Cement-retained crowns rarely loosen but are harder to service when other problems arise.
- Space requirements: Screw-retained crowns are often recommended when there’s limited space between your upper and lower jaws (as little as 4 millimeters), since they don’t need the extra bulk that cement-retained designs sometimes require.
A systematic review comparing both types found that screw-retained restorations generally posed fewer biological and technical complications overall. The review noted that cement-retained crowns remain a good choice when cost is a concern or when implant positioning makes it difficult to place the screw access hole in a discreet location. But the biological risks of excess cement have pushed many clinicians toward screw retention as the default.
Abutment Materials
The abutment connecting your implant to the crown is typically made from either titanium or zirconia (a white ceramic). Titanium is mechanically stronger and has a long track record. Zirconia offers a slight cosmetic edge because its white color doesn’t create a grayish shadow through thin gum tissue the way titanium sometimes can. A review of systematic reviews found that zirconia abutments scored higher on gum appearance assessments, particularly a measure called the Pink Esthetic Score, which evaluates how natural the tissue around the implant looks.
In practice, the difference narrows over time. When the gum tissue around an implant is thicker than about 3 millimeters, the abutment material becomes largely invisible, and long-term studies show no significant difference in cosmetic outcomes between the two materials. Titanium collects slightly more plaque, while zirconia shows marginally higher bleeding rates on probing, but neither difference reaches clinical significance. Your dentist will typically choose based on the location of the implant: zirconia for highly visible front teeth with thin gums, titanium for back teeth or areas where strength matters most.
What the Attachment Appointment Feels Like
By the time your crown is ready to attach, the surgical phase is long behind you. Your dentist removes the healing cap that’s been sitting on top of the implant to keep the gum tissue shaped properly. For a screw-retained crown, they’ll place the crown-abutment assembly onto the implant, thread the screw in with a hand driver, then apply final torque with a wrench. You’ll feel pressure but no pain since the implant has no nerve endings. The screw hole is packed and sealed, your bite is checked, and you’re done. The whole appointment typically takes 30 to 45 minutes.
For a cement-retained crown, the abutment goes on first and is torqued into place. The crown is then tried on to verify fit and appearance before being cemented permanently. After seating, your dentist spends time cleaning away any excess cement, sometimes using dental floss and an explorer to check beneath the gumline. A follow-up visit shortly after placement helps catch any cement remnants that might have been missed.