So the point is covering the occlusal surface: if it is covered so it is Onlay but if not it is Inlay. This is Inlay, but it could be Onlay if we cover the mesiobuccal cusp. These Inlays or Onlays could be made out of metal or ceramic or other materials and unlikely to have two layers metal and ceramic, so unlikely to have combination of these materials. The other type is the Inlay which restores mild to moderate lesions without occlusal coverage. And Onlay in dentistry means “cover the top”, for that reason called Onlay.
Here we have MOD that covers the palatal cusp, this is called Onlay. If you have Intra-coronal restoration and it covers part of the occlusal surface like the picture below: The former( which is inlays) restore mild to moderate lesions while the latter restores more extensive lesions with occlusal coverage. This picture below is complete crown which surround the whole surfaces of the tooth, if you look there, you can notice that the palatal surface is metal and the labial surface is ceramic, this is combination of metal and ceramic, it could be metal by it self or ceramic by it self or combination of both.įor Intra-coronal restoration it is unlikely to be a combination, it is either metal or ceramic or other material, it can not be combination for certain consideration which will be explained later on.Īre intra-coronal restoration (within the confined of the tooth) artificial replacement that restore missing tooth structure. The picture below explain what we mean by partial crown which covers mesial, distal and the palatal surfaces, but the labial surface is off. From material point of view, 1)they could be cast (cast restoration is the restoration where you need to fabricate a mold usually out of wax and this will be replaced later on with molten material which could be metal or ceramics ) 2) they could be only ceramics, or 3)combination metal and the top of that a ceramic layer. From design point of view, they are either Partial Crown or Complete Crown. The crown could be made of ceramic or metal or combination of them or other material. **Complete/Full Crowns: surround the whole tooth structure. **Partial Crowns: surround one surface or more but they don’t surround the whole tooth structure.
It is an artificial replacement that replace missing tooth structure (if it is replacing missing tooth then it is bridge or fixed partial denture)by surrounding part of the tooth( we call it partial crown) but if surrounding the whole tooth (it’s called complete or full crown) with a material as 1)cast metal, 2) ceramics or 3)combination of both. Both Intra-coronal and Extracoronal are fixed because they are looted to the tooth structure. restoration that covers the outer surfaces of the tooth(cover part of the tooth or all the tooth). The restoration of single teeth (which they are there but damaged) could be: 1- Intra-coronal: means within the confines of the tooth(within the anatomy of the tooth), it is like a filling but it is not, because it is cemented or screwed-in. So it is a wide range of treatment from single tooth to rehabilitation of the entire occlusion. Which means, the patient may complaine of a bad broken tooth and you need to restore it with a crown which is a fixed prosthodontic and he might come to your clinic with no teeth and you need to rehabilitate him with fixed prosthodontics which could include implants. The scope of this field can range from the restoration of a single tooth to the rehabilitation of the entire occlusion. Restoration in this field could be the finest service (you can give excellent service to the patient if your work is excellent) or could be the worst disservice (if you are bad), usually fixed prosthodontics lead us to irreversible outcome if goes bad. So it is fixed because it has been screwed to the structure underneath it either by screws or cements. But it has to be luted, cemented or screwed-in, this is why we call it fixed, the patient can not remove it and sometimes the dentist can not remove it. Cemented means using cement : conventional cement, Glass Inomer cement, RMGI or Resin cement. Fixed Prosthodontics Crowns and bridges lec 1 18.02.09 It is the art and science of restoring damaged teeth with 1) cast metal, 2)metal-ceramic or 3)all ceramic restoration and replacing missing teeth with fixed prostheses(cemented or screwed-in).