A patient presents for an evaluation with the primary concern that the “bite” has never felt right following insertion of dental implant supported restorations in the area of 14 and 15. The distal marginal ridge of 15 has fractured and after drying the occlusal surfaces, it appears that several adjustments have been made confirming the patient's description of events.

molar implant restorations
molar implant restorations image 2

The pre-treatment radiograph of 14 and 15 demonstrates the restorations cemented on the abutments with a distally positioned dental implant. The Straumann Bone Level implant is designed with a platform-switching concept, and is placed with adequate depth with supporting bone structure that appears to be intact. The abutment margin of 15 is visible apical to the margin of the “cement on crown” where 14 appears to have a better adaptation than 15.

Take a look at the cemented restorations (15 has the fractured distal marginal ridge) and evaluate the cement specifically on the buccal aspect of the abutment for the restoration at 14 – presumably the easiest area to remove the cement.  Compare the cement visible on the abutment to what you see on the pre-treatment radiograph.

The tissue attachment in the area surrounding a dental implant allows for cement to flow much farther apically than would be expected with natural teeth. Peri-implantitis, depending on how the literature is interpreted, could be more common today than periodontitis. Problems related to cemented dental implant supported restorations occur in a time range of about four months to nine years with an average time to adverse event of just under three years. There are two times more cytokines present around dental implants than natural teeth and appear to be the etiologic agent of the breakdown of the supporting structure. Interleukin-1 Beta is a potent bone resorbing cytokine that has been found in peri-implantitis.

molar implant restorations image 3

Dr. Bruce Houser has defined Cement Initiated Disease (CID) as iatrogenic with the disease process specifically initiated by excess dental cement. Considering the location (14 and 15) and required contours of the planned maxillary molar restorations as a result of the distal position of the dental implants, how effective is it to remove radiolucent or radio-opaque cement? How about screw-retained restorations in the posterior?

Douglas G. Benting, DDS, MS, FACP, Spear Visiting Faculty and Contributing Author. www.drbenting.com 


Commenter's Profile Image Bruce Houser
April 11th, 2014
Doug, thanks for presenting that case. Unfortunately, cement initiated implant failure is a far to common occurrence. There is compelling evidence that links cements to increased inflammation around implants and this ultimately can lead to implant failure. Based on current research a move to screw retained implant restorations is advisable. UCLA cast to abutments are a great option for screw retained restorations. There is also a new "Screwmentable" restoration technique available. In this technique the custom abutment and crown are cemented together out of the mouth, and cleaned extra-orally. Access is created in the crown then the crown-abutment complex is screw retained and access is sealed with teflon tape or polyvinyl then composite.