Nov
In responding to a patient’s question today regarding onlays, I realized there still remains a lot of misinformation about what this type of restoration is as opposed to a crown or “cap.” In this practice, a primary goal is to restore the function of teeth with the most conservative method possible that provides the best possible long-term outcome.
Anyone who has needed to run to the restroom during a crown preparation appointment, and couldn’t help looking, can usually attest to their genuine surprise at the amount of tooth remaining after the procedure. This is because crown preparation requires the removal of a significant amount of tissue (enamel and dentin). In contrast, an onlay can require much less tissue removal thereby diminishing many post operative complications.
Onlays require more thought and technique savvy than preparing for a crown, but I feel they are worth it. Especially as superior bonding techniques allow dentists to rely less heavily on “locking” a restoration onto a tooth based purely on mechanics.
Both onlays and crowns are used when a tooth is missing structure – too much structure to accept a filling successfully. Reasons include: a large filling that is defective, a portion of the tooth is fractured off, the tooth has a crack, or tooth decay- to name the most common. The choice of whether to place an onlay or crown is not random, nor is the choice of materials the dentist practitioner uses to place unimportant. The simple reason for this can be summed up in one word – conservation.
Tooth tissue cannot be re-grown, only imitated and should be respected. Onlays require less radical tissue removal and the edges of the restoration can often be placed in areas that are more easily cleanable than those of crowns. The conservative onlay often allows for the tooth to be re-prepared should the need arise years later. Re-preparing a crowned tooth involves more risk by far.
Onlays and crowns are both viable ways to restore teeth, I do necessarily rule out the ability to place an onlay before a crown is ever considered. Onlays are the strong, conservative, restorations of choice when ever possible.
Best,
Dr C.