A crownlay is a type of dental restoration.
Description
A crownlay is a hybrid
dental restoration
Dental restoration, dental fillings, or simply fillings are treatments used to restore the function, integrity, and morphology of missing tooth structure resulting from caries or external trauma as well as the replacement of such structure suppor ...
typically placed over an
endodontically treated tooth that is more conservative than a normal full coverage
crown
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...
, but less conservative than a normal only. Crownlays incorporate an extension of extra restorative material on the underside of the restoration into the excavated
pulp chamber following
root canal therapy, taking advantage of the extra surface area afforded in this space on the interior aspect of the preparation, thereby sparing the external walls from needing as much tooth reduction. The use of a crownlay results in the conservation of more healthy, natural tooth structure than is otherwise possible.
File:CAD-CAM_diagram_of_root-canal-treated_molar_prepared_for_crownlay.jpg, 2009-03-31T15:01:33
Root canal treated molar prepared for CAD/CAM crownlay
File:Milled_crownlay.jpg, 2009-03-31T15:39:56
crownlay milled
File:Crownlay_try-in.jpg, 2009-03-31T15:37:49
File:Crownlay.jpg, 2009-03-31T16:42:44
Usage
Crownlays are typically used in place of traditional
post and core
A post and core crown is a type of dental restoration required where there is an inadequate amount of sound tooth tissue remaining to retain a conventional crown. A post is cemented into a prepared root canal, which retains a core restoration, w ...
restorations. Post and core buildups are essentially rods of restorative material made out of titanium, stainless steel or resin that glean extra surface area against the internal walls of root canal-treated teeth when there is little to no teeth left above the gumline to hold a normal crown or
onlay in place. The post and core buildup serve to aid in retention of a traditional crown but increase the likelihood of root fracture because chewing forces are directed vertically along the hollowed out and subsequent weaker remnants of the internal surfaces of an endodontically-treated (root-canal-treated) tooth. Crownlays are typically constructed from milled, monolithic blocks of solid porcelain which not only very intimately fit the prepared tooth, but are acid etched and bonded into place using very strong resin materials, decreasing the need for physical retention.
References
External links
The Academy of CAD/CAM DentistrySame Day CAD/CAM Dentistry, p. 41
Dental materials
Restorative dentistry
Prosthodontology
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