State of the Art in Posterior Restorative

Shadeguides - Tips and tricks - Indirect posteriors - Direct posteriors
14 Mar 2016

The restorative procedures of posterior areas are the most frequent in our daily practice. Despite the fact that composites are used in posteriors since more than twenty years, there’s still a lot of confusion about when to choose a direct technique or an indirect one, and when to do surgery or not. At the same time, indeed, when restoring we must have a perfect isolation, that means that we do not have to select shortcuts: when surgery it’s mandatory, we have to perform it, to obtain a proper isolation, good impressions, and a perfect sealing. This Article clarifies how and when to chose a direct approach or an indirect one, depending on the clinical indications.

Fig. 1

Fig 1.- A male patient, 27 years old, came to my attention by a sharp pain spread to the lower left arch. He referred to not be able to locate the pain, although he realized to perceive the presence of a cavity, of large size, in one of the lower left molars. The patient also reported having non regular eating habits, to consume sugary food and drinks, just to wash and rinse his teeth, not flossing. In the picture, the initial situation of the upper arch

Fig. 2

Fig 2.- Initial situation of the lower arch

Fig. 3

Fig 3.- Details of the 3rd quadrant

Fig. 4

Fig 4.- Details of the 4th quadrant

Fig. 5

Fig 5.- Bitewing and periapical X-rays of the 3rd and 4th quadrants. A lot of decays are present on the lower arch. Little spots on the upper too.

Fig. 6

Fig 6.- Isolation of the 3rd quadrant

Fig. 7

Fig 7.- After the cleaning of the biggest decay, it was necessary to perform a root canal treatment: the patient was referred to my brother and team-mate Dr. Paolo Marchetti, for the endo procedures. A provisional build up was done by me on the distal wall in order to contain the irrigating liquids

Fig. 8

Fig 8.- After the removal of the decay it is clear that the rubber dam will not isolate properly. In these situations we do not have to try to put in place a matrix, with the rubber dam on it, because this will lead to a failure, due to the impossibility to control the moisture coming from the gingival sulcus. On the other hand it is clear at the same time that the only removal of gum, with radiosurgical procedure, burrs or else, is not the solution, because this will probably cause periodontal problems, if not immediately, in a second time, for the nearness between the bone and the restoration. The correct clinical solution is to remove the dam and do a fast and conservative crown lengthening

Fig. 9

Fig 9.- A minimally invasive crown lenghtening was performed by the perio surgeon, (again my team-mate Dr. Paolo Marchetti) and the right biological width was re-gained.

Fig. 10

Fig 10.- Details of the suture. The gutta-percha was protected with flowable composite without doing adhesion.

Fig. 11

Fig 11.- Immediately after the surgery, the rubber dam was placed and the build up performed.

Fig. 12

Fig 12.- The cusps were reduced with a big grained diamond bur. The correct reduction is 1.5-2 mm for the composites overlays. Less than this will probably cause the fracture of the restoration. It is a butt joint prep, with no external bevels, because they would reduce the thickness of the material and cause its fracture. Instead with a flat preparation we will not risk to fracture our work, during the chewing loads, due to the insufficient thickness.

Fig. 13

Fig 13.- Details of the finishing of the cervical step, with sonic tips

Fig. 14

Fig 14.- Details of the cervical margin finishing with sonic tips

Fig. 15

Fig 15.- The prep is polished with a brownie rubber.

Fig. 16

Fig 16.- Details of the Overlay preparation of 3.7

Fig. 17

Fig 17.- Details of the Overlay preparation of 3.7

Fig. 18

Fig 18.- At this point we can do the direct restorations where needed. Details of 3.5 3.6

Fig. 19

Fig 19.- The interproximal caries on 3.5 and 3.6 are accessed from the occlusal surface.

Fig. 20

Fig 20.- A caries detector was used to ensure all the infected tissue removal

Fig. 21

Fig 21.- After only 10 seconds after its application is rinsed off . The dentin affected by the decay will remain colored.

Fig. 22

Fig 22.- Details of the preps for direct restorations. The preps must be done in a way that the matrices will fit passively.

Fig. 23

Fig 23.- Detail of the distal prep on 3.6

Fig. 24

Fig 24.- A sectional matrix blocked with a wooden wedge. In order to increase the fitting on the cervical margin sometimes is necessary to place PTFE (Teflon tape), between the matrix and the wedge

Fig. 25

Fig 25.- A separating ring is also placed. Details of the cervical margin and of the matrix fitting.

Fig. 26

Fig 26.- We proceed for the adhesion steps with a self-etching technique. Only the enamel is etched for 30 seconds, after dentin cleaning with glycine powder, and its disinfection with 2% clorhexidine

Fig. 27

Fig 27.- The self etch product is applied both on dentin and enamel, it is brushed for 40 seconds and light cured for 40 seconds as well.

Fig. 28

Fig 28.- Details of the build up of the distal wall with a dentin mass (to increase opacity and contrast of the ridge). Before the removal of the matrix a little amount of flowable composite is used between the dentin and the distal wall, in order to stabilize the wall for matrix removal safety.

Fig. 29

Fig 29.- With the same dentin mass we do 70% of the volume of the distal restoration and start insinuating the anatomy with the modeling.

Fig. 30

Fig 30.- A enamel is chosen and used in order to do the micro anatomy of the occlusal surface. This strategy is optional, when we want to have the best chromatic outcome. In fact, most of the times in the posterior region we can use just one body mass to reproduce the anatomy and have almost the same perfect outcome.

 

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