Step by step protocol: Restoring the first upper molar
Lots of dentists often have difficulties in restoring the natural occlusal anatomy of posterior teeth, especially because of the occlusion aspects which must be considered.
This article’s aim is to illustrate in a didactic way a step by step protocol for getting a good morphology for our class I direct restorations on the first upper molar.
Img. 3 – It is very important to have a perfect finished cavity (Img. 1,Img. 2) and to observe, first of all, the elements of the natural occlusal anatomy of the natural tooth: the 4 cuspids (mesio-palatal, mesio-buccal, disto-buccal and disto-palatal), the oblique ridge, the central fossa, the mesial and the distal triangular fossa (Img. 3).
Img. 4 – The most important element is the central fossa, as this is the starting point of all the functional movements. The tip of the mesio-buccal cusp of the first lower molar interdigitate with the central fossa of the first upper molar. After positioning the central fossa we must imagine all the functional movements. The central fossa is delimited by the central part of the mesio-palatal cusp, the disto-buccal cusp and the mesio-buccal cusp.
Img. 5 – The first increment of composite will be used to reproduce the central part of the mesio-palatal cusp (Img. 5, Img. 6), which has another 2 small components (that will be build later).
Img. 7 – Every layer must be perfectly adapted to the margin of the preparation in order to prevent time wasting finishing adjustments.
Img. 8 – The next cusps that we will build are the disto-buccal and the mesio-buccal cusps (Img.8 – Img. 13). In this order, we can build all of the 3 main cusps of the upper first molar. It is essential to use a very well defined quantity of composite materials in order to obtain a very clean anatomy of every cusp and not to use a large amount of composite to build all the anatomy in one step.
Img. 14 – The next step will be the building of the small medial part of the mesio-palatal cusp (Img. 14, 15, 16), followed by the distal part of the mesio-palatal cusp (which will form the oblique ridge) (Img. 17, 18, 19).
Img. 20 – The last cusp that will be built is the disto-palatal cusp, which is the smaller one (Img. 20, 21).
Img. 22 – Moreover, the medial part of the occlusal surface is now very easy to reproduce (Img. 22, 23).
Img. 24 – It is important to avoid using straight lines in this process in order to obtain a very natural look and a good final result (Img. 24, 25).
Regardless of what treatment is to be carried out, it is very important to follow a good protocol, and this principle is also available for class I direct composite restorations on the first upper molar. Following the steps described in a stepwise manner (Img. 26), it will be easier and with more predictable results to restore this type of cavity.
I would like to thank Dr. Lazar Dan for his support the writing of this article.