As patients have more teeth restored with tooth colored restorations, their desire to have esthetic restorations are also increasing. For patients who care about esthetics, an alternative to full crown preparation are ceramic onlays. Since the tooth is already stressed from the large old restorations, less preparation is very important to maintain healthy pulp tissue. Many old amalgam fillings in people’s mouths can be replaced with bonded ceramic restorations (figure 1). These preparations can be done quickly since you only remove the bad portions and leave the rest. When the entire enamel shell of the tooth is removed for a crown preparation this exposes all the dentinal tubules to bacterial penetration. The onlay preparations leave an enamel band almost all the way around the tooth (figure 2) – your “ace-in-the-hole” for bonding. This allows for enamel and dentin bonding for the restoration, giving a great bond and an excellent seal. In my experience, the chance for root canals decreases due to this less aggressive preparation of the tooth. If a large amount of dentinal tubules are exposed, then the chance for a greater bacterial penetration into the tooth causing pulpitis and potential nerve death increases.
There are multiple advantages to esthetic onlays such as the ability to place the margins of the restoration above the gum line and be invisible. The impressions are accurate on the first try nearly every time (figure 3). The temporaries are done with a material-like integrity and are shrink wrapped onto the tooth (no temporary cement needed) (figure 4). The esthetics is superior to restorations containing metal frameworks.
The color of the remaining tooth blends into the restoration (figures 5, 6). There are no dark areas at the gumline since there is no metal. The occlusion is usually very easy to adjust since the remaining tooth gives you a good occlusal stop. Since these restorations are bonded in, post-operative sensitivity is almost non-existent. Due to this bonding process there will be less micro-leakage than a conventional crown. The bonding is done while the teeth are isolated with a rubber dam. This process is very clean and neat since there is typically no need for retraction cord.
In my practice I have found that the time needed to prepare these teeth for onlays is significantly less, since preparation is conservative. The other observation is the decrease in pulpitis after these restorations. My patients rarely return after their restorations with complaints or adjustments. Another interesting fact is that patients now request this type of procedure when they require restorations. There is a learning curve to this type of procedure, but there are several educational centers that offer additional training.
For more information about Bonded Ceramic Onlays contact us today.