In a previous article, I discussed the pros and cons of both screw-retained and cement-retained implant restorations. In my own practice I have been increasing the number of screw-retained implant restorations for a variety of reasons but the main two are retrievability and eliminating the need for cement.
It is always nice to have the option to easily remove an implant crown or re-tighten the screw if the need were ever to arise. By removing cement from the equation, you remove the risk of leaving cement subgingivally that could cause peri-implantitis. Another factor that may be taken into consideration on whether you do a screw-retained or a cement-retained restoration is the comparison of the laboratory cost. Typically, the screw-retained implant crown will be associated with a lower lab bill because it is generally less time consuming to make.
If you desire to have a screw-retained implant restoration prior to beginning treatment, this information should be brought to the attention of the surgeon so that the orientation/angulation of the implant can be positioned accordingly. Although this typically does not pose a problem with posterior implants. The posterior implants are more axially positioned with regard to the alveolus and tooth. It may be an issue with anterior teeth where the anatomy of the hard tissues may not allow the screw access hole to exit palatally.
So, where do I choose to use screw-retained restorations over cement-retained? Generally, I find I place more of them in the posterior - upper posterior more often than the lower posterior - and I tend to use screw-retained restorations on complex multi-implant cases, especially ones that require pink porcelain.
The goal of having the restorations on these complex cases as screw-retained is retrievability if problems occur, hygiene (easily cleaned) and passivity of fit if the abutments are picked up in the mouth to finalize the screw-retained prosthesis.