What is the difference in a crown or onlay
All dentists are trained to do crowns which cover all 5 surfaces of the tooth ( the whole tooth). Onlays are different in that they only cover part of the tooth ( three or four surfaces). To design and prepare an onlay requires a good deal more designing skill than doing a full coverage crown. When done properly, either one will bring the tooth back to 100% of its original strength.
The reason an onlay is better is that good tooth structure is saved. The original tooth structure is superior to any man made material and so if we can save any tooth structure, the patient is far better off. Crowns and onlays can be made out of gold, all porcelain,porcelain fused to gold, or plastics. We use Cerec Technology ( CAD-CAM instrument) to fabricate porcelain bonded restorations in one appointment. Bonding is superior to cementation and, since metal does not bond well to tooth structure,we choose porcelain or plastics over metal anytime. Crowns or onlays can be done to replace large mercury fillings, resin fillings, to repair fractured teeth or to replace existing crowns or onlays.
Unless you have this CAD-CAM technology, these procedures are much harder to do and require multiple appointments. That means more shots and temporaries in between appointments. Patients have told us they love having one appointment instead of multiple appointments because there is only one shot , no sensitivity and less lost hours at work.