The power of pencil
Who would not wanna predict the future? In direct composite in anteriors curiosity is always there during treatment… In starting the procedure we use wax-up and mock-up to see where to end up. We lightcure composite in the colour mock-up to try to see the outcome. Besides defining form and shape by silicone matrix and exploring the internal colour anatomy, we need one other crucial thing in the treatment to look forward in time: a pencil. To see the incisal thickness and to identify the transitional lines in our restoration. And to see if they match….Before the polishing stage there is no luster so you can not judge if they are in the correct place by lack of light reflection. And after polishing you absolutely do not want to touch and redo. This article will guide you through the steps to the desired and defined end result.
The POWER of PENCIL-direct composite
Initial situation: patient had been in a bus-accident 9 years ago and suffered a trauma on tooth #21. Tooth had an enamel-dentin fracture without pulp involvement and was partially displaced out of its pocket. It was repositioned and an endodontic treatment had to be performed by the endodontologist Marga Ree. 8 years later internal bleaching was performed because of discoloration that had developed over time. A composite build-up and fiberpost were placed. Patient was referred and came in to improve the coronal part.
Shape, form and colour were not satisfactory to the patient.
The transition of composite into tooth structure is highly visible. Treatment goal defined: make an invisible restoration and tooth # 21 identical to tooth #11. By colour mock-up it was decided to use an A2 body overneath an A3 dentin core combined with a translucent enamel and a white enamel shade.
After taking preoperative photographs impressions were made in order to make a wax-up. The wax-up shows proper form and shape. Surface structure in wax is not necessary. The wax-up serves to make a mock-up and a silicone index to transfer the result intraorally during the treatment.
Patient had orthodontic treatment in the past. Palatal of the anteriors superior a fixed retainer was in situ. The silicone index was cut away thoroughly to fit. This is not always possible depending on the position of the retainer. A shadow on the incisal edge shows perfectly the edge has a certain thickness.
After the restoration is made the rubber dam is removed and obvious roughness smoothed. A pencil is taken to draw the first line on the labial side of the incisal edge. The next line is on the palatal side of the incisal edge ending up with two lines.
All images illustrating the incisal part in this article are placed in operator view to see more clearly.
This is also done on the intact tooth #11 to be able to compare both teeth.
From a mirror view an obvious difference in incisal thickness can be seen. The restoration is bulky at the labial side. On the palatal side can be trusted: this side is completely based on the wax-up and silicone index by means of a palatal shell of composite.
In close-up view it is easily seen that the labial pencil line is not in sync with the silicone matrix. The silicone matrix is leading because already approved by the patient and operator by mock-up.
A Sof-Lex disc is used at low speed and no water to trim back the composite at the incisal 1/3.
The pencil lines are drawn again. The pencil is made long and draws its lines passively. Not with the tip but with the side.
The putty put in place shows another reduction of the composite is needed and is performed by disc again.
Pencil lines are passively drawn again.
The silicone index is in sync with the labial pencil line. At this time the convexity of the labial surface can be checked knowing the incisal 1/3 part is in the exact right position.
The next step is getting your transitional lines deflecting the light in the right way. The right way in this case, with an intact perfect neighboring central incisor, can be seen clearly by using the pencil on tooth number 11. The goal defined. The pencil lines tell that the restoration has to be adjusted to match.
To adjust a worn Sof-Lex disc can push the pencil line to outside, or….
Pull the pencil line to inside, using low speed to keep full control.
Draw again in order to check and adjust again. Transitional lines deflect the light in the end result. Asymmetry of these lines comparing #11 and #21 is just as disturbing to the eye as asymmetry in the outlines of both teeth.
Small steps and repetition are key words to keep full control.
To check symmetry of your pencil lines the interlinear distance can be measured with a digital caliper . Starting with the ideal width, fastening the caliper and transferring that width to the pencil lines on the restoration to compare and adjust.
Now it is easily to be seen that the interlinear distance is too big and should be made smaller.The caliper measurement can be done on the incisal third, middle third and on the cervical. The digital caliper reads more precisely than the eyes can see.
Getting there; the mesial pencil line needs just a little last adjustment to match the characteristically rounded shapes of tooth #11.
While adjusting the transitional line with the disc and before checking with the pencil the appearance of a white powder dust line gives a clue on how the line is changing.
The incisal thickness, facial curvature of the restoration creating convexity and the position of the transitional lines are correct. Ready for the next step: adding facial anatomy.
The surface is rubbed with carbon articulating paper to see the effect of the diamond bur moving very softly and with very low speed creating the depressions of the secondary anatomy lobes. In this case the surface structure aimed for is subtle. To give the anatomy an organic form, an overused Sof-Lex disc can by used to slightly wipe out the marks that appear to be too strong.
Tertiairy anatomy like perikymata can be placed by moving a green Arkansas stone horizontally once by hand. Again subtle in this case.
The multistep polishing procedure starts with Sof-Lex spiral elastomer wheels. Starting with beige.
Ending with the white one. Performed without water.
Next step is to use an aluminiumoxide paste together with a felt coated disc. The disc makes it easy to reach all corners of the restoration because of its flexibility.
The big felt wheel can be used on the flat surfaces.