A Method of Cementation of Multiple Crowns

When I was in dental school, I was taught that it can be OK to seat multiple crowns at the same time. In fact, it was such a common practice at the time to simultaneously seat more than one crown that I was proud of myself for having seated six crowns at once during my residency program. I was young and enthusiastic.
Over the years, working in my private practice, I realized that there was something not-quite-right in performing the cementation of multiple crowns at once. Even though each individual crown fit perfectly on the stone die and on the abutment tooth during the try-in by single crown, I often found that the marginal seating of these crowns was incomplete after cementation.
Through years of experience and research, I found that I had to consider two things when seating crowns: 1) Interproximal Relief (FAQ), and 2) Compensative Relief of the working stone die.
To compensate for the thickness of crown cement material, lab technicians paint thin layers of coating on the working stone die or, in more modern workflows, digitally alter the models in their CAD machines to manipulate the thickness of crowns. These manipulations allow the crowns, when seated on the abutment prior to cementation, to be forgiving of lateral movement. The accumulation of this forgiveness of lateral movement across multiple crowns significantly affects proximal contact adjustment; once the crowns are cemented, that forgiveness of lateral movement is gone, and proximal contact is much tighter than anticipated. This can cause the incomplete marginal seating of some crowns.
Therefore, when performing the cementation of multiple crowns, I do a maximum of two crowns at a time, starting from the free-standing abutment teeth. And, crucially, I make sure to repeat proximal contact adjustment of each crown prior to its latter cementation.

Fig.1 The lower anterior crowns for abutment teeth #24, 25, 26 and 27 are ready, and #24 and 27, which are freestanding, are cemented prior to teeth #25 and 26.

Fig.1
The lower anterior crowns for abutment teeth #24, 25, 26 and 27 are ready, and #24 and 27, which are freestanding, are cemented prior to teeth #25 and 26.

Fig.2 Crown #26 is placed on the abutment tooth, and the proximal contact is adjusted by using the Black Diamond Strip.

Fig.2
Crown #26 is placed on the abutment tooth, and the proximal contact is adjusted by using the Black Diamond Strip.

Fig.3 Crown #26 is removed, and crown #25 is placed on the abutment tooth. The proximal contact is then adjusted.

Fig.3
Crown #26 is removed, and crown #25 is placed on the abutment tooth. The proximal contact is then adjusted.

Fig.4 Crowns #25 and 26 are placed on the abutment teeth and the proximal contacts are adjusted.

Fig.4
Crowns #25 and 26 are placed on the abutment teeth and the proximal contacts are adjusted.

Fig.5 Abutment teeth #25 and 26 are cleaned and ready for crown cementation.

Fig.5
Abutment teeth #25 and 26 are cleaned and ready for crown cementation.

Fig.6 Crowns #25 and 26 are cemented onto the abutment teeth, and two thumbs are used to press and hold each crown while the cement is getting hard. The White Serrated Strip is used to cut and clean out the cement in the interproximal space.

Fig.6
Crowns #25 and 26 are cemented onto the abutment teeth, and two thumbs are used to press and hold each crown while the cement is getting hard. The White Serrated Strip is used to cut and clean out the cement in the interproximal space.

Fig.7 Crowns #24, 25, 26 and 27 are cemented,  cleaned, and Interproximal Relief is confirmed by Gray Final Polishing Strip.

Fig.7
Crowns #24, 25, 26 and 27 are cemented,  cleaned, and Interproximal Relief is confirmed by Gray Final Polishing Strip.