Yes, a screw access hole can potentially weaken a zirconia or ceramic restoration. It introduces a stress concentration point, and studies show it can reduce the fracture resistance by up to 30%. However, proper design, ensuring adequate ceramic thickness (at least 1.5mm) around the hole, and careful bonding of the composite plug can significantly mitigate this risk, making it clinically reliable for most posterior applications.

The most effective technique involves using an abutment replica. After filling the crown with cement, seat it on the replica outside the mouth and remove the gross excess. Then, seat it intraorally. For final cleanup, wait for the initial set (around 2 minutes), then use a scaler and knotted dental floss to carefully clean the margins. Taking a radiograph immediately after cementation is the only definitive way to confirm all cement is removed.

The costs can be comparable, but they vary. Screw-retained crowns may have higher initial lab fees due to the need for precise componentry and technical expertise. Cement-retained crowns might have lower lab costs but can incur future expenses if complications like peri-implantitis arise, which may require surgical intervention costing significantly more than the initial restoration. Overall, the long-term value of a predictable, serviceable restoration is the most important factor.

Implant angulation is a critical factor. Screw-retained systems work best when the implant is placed in a restoratively ideal, non-angulated position. If an implant is angled by more than 15-20 degrees, the screw access channel may emerge on the facial or incisal surface, which is unaesthetic. In these cases, a custom-angled, cement-retained restoration is often the only viable solution to achieve a proper path of insertion and aesthetic outcome.