Core buildups

Core buildups before crowns is a step that is important for the retention of a crown. It removes undesirable undercuts in the tooth, provides a material to shape the tooth to an ideal resistance form and in aesthetic cases can change the stump shade of the tooth for aesthetic effect.

In full mouth cases core buildups are much more efficient than those in single crown cases because you don't have to worry about things like damage or bonding to the adjacent tooth. Rubber dam is desirable for gingival retraction and moisture control but this is not always possible. You will find it much easier to perform an occlusal reduction from the desired vertical dimension before your core buildup. A shrink wrap mock up transfer can be done and burs of ideal depth used to prep the occlusal surface of multiple teeth at an angle following the contour of the cusps. Old restorations can then be removed much easier due to improved visibility.

Remove all stains especially at the DEJ till you are on solid, good quality tooth structure. If it looks wrong it is probably not right. You then need to only fill the gaps with a compsite material and as it will be prepped immediately after you don't have to worry about matrix bands and shaping the material etc.

Hemostasis is key before bonding procedures commence. If rubber dam is applied you are usually set but teflon cord can be packed in the interproximal areas if there is tearing or leaking of the dam. Without rubber dam, teflon cord and hemostatic agent soaked cotton pellets can be packed into the interproximal soft tissues for hemostasis. wait 5-10 minutes for good hemostasis before removing and if it starts to bleed then reapply and wait again.

Etchant is not required as the enamel margins will be cleared of composite resin in the final preparation. sandblasting may be desirable. SE prime and bond is the gold standard in bonding and this should be applied liberally for sufficient time. light air blowing should start from far away and the primer should be thinned slightly. SE Bond should be used after this and the same air thinning protocol with full light cures afterwards.

A thin flowable layer should be placed on the tooth surface and cured to reinforce the bond and ensure good adaptation of the material. An unset layer of flowable can be applied between cures to minimise voids. Packable bulk fill composite should be applied after this and it should force the flowable composite out to a
thin layer. In multi unit cases, you don't have to worry about contact points or overhangs.  Just force the composite in with no voids and your prep afterwards will neaten everything up. The good thing about occlusal reduction beforehand is that you know where to build the composite resin up to afterwards

After completing your final cure, prep interproximally slowly starting from the occluslal surface in a sweeping motion. try not to force the bur gingivally. eventually with slow vertical removal of the material you will uncover the rubber dam or teflon cord and you know you have separated the teeth. You can then proceed as normal and finish your preparations.