Successful temporary restorations

18 October, 2011 / Infocus
 

The demands of our patients regarding prosthetic restorations are constantly increasing. Thus, not only restoring the function, but also the aesthetic appearance of the smile, has become more and more important.

Not without reason, the many different advertising media portray a flawless, brilliantly white smile representing professional and social success. The alteration of just one tooth, the placement of a single crown, can have a significant impact on the patient’s overall appearance, both positively and negatively.

In order to define and match the expectations of the patient as precisely as possible, the application of temporary restorations has not only proven effective for protecting prepared cores, but also for simulating the desired final aesthetic result. Temporaries play an ever more important role within the dentist-patient communication process in aesthetic dentistry.

Case report

A 50-year-old patient was dissatisfied with the aesthetics of her smile. She was particularly bothered by the appearance of the crown on tooth 11 (Figure 1). This porcelain-fused-to-metal (PMF) crown had been placed approximately 10 years earlier, following an endodontic procedure and the integration of a customized metal post.

The patient complained in particular about the dark margin of the crown, the lack of translucency and the shape of the crown itself. During the palatal examination, an exposed crown margin and cracks in the ceramic veneer were detected (Figure 2).

An X-ray did not reveal any sign of apical inflammation. As the placement and marginal fit of the cast root post was judged to be clinically sufficient it was decided to leave the post in situ. Following fabrication of the evaluation models and an analysis of the initial situation, a restoration with an all-ceramic crown was planned. Since no corrections of the gingival margin were necessary and we would be able to prosthetically close the oversized interdental triangle, the existing crown was removed (Figure 3). A temporary impression was taken with StatusBlue (DMG, Hamburg, Germany) (Figure 4) beforehand.

Following removal of the old PFM crown, dark discolourations of the dentine were detected on the margins (Figure 5), which could be completely removed in the course of the subsequent follow-up preparation. For the placement of the all-ceramic crown the existing cervical margin was widened. After finishing the preparation, the temporary impression was adjusted and the palatal margin extended accordingly (Figure 6). With a Vita shade guide the shade for the temporary was chosen.

The temporary impression was filled homogenously and bubble-free with Luxatemp-Fluorescence (DMG, Hamburg, Germany) (Figure 7), replaced in the patient’s mouth and left to set in situ for two minutes. During subsequent removal of the matrix the temporary remained inside the impression (Figure 8). The Luxatemp temporary was removed from the matrix, repositioned and fit, shape and shade examined (Figure 9). Subsequently, the surplus and excess material was removed. The finishing and final shaping of the temporary was performed outside the patient’s mouth using burs.

In order to provide the patient with a preview of the final aesthetic result some material was removed from the facial surface of the temporary and the natural shading of the tooth was imitated using LuxaFlow-Fluorescence (DMG, Hamburg, Germany). Subsequent to finishing and polishing, the temporary was varnished with Luxatemp-Glaze&Bond (DMG, Hamburg, Germany) (Figure 11). This sealer gives the temporary a natural glow, prevents discolourations and minimises bacterial colonisation on the temporary’s surface. The temporary was cemented in situ with some eugenol-free temporary luting cement, TempoCemNE (DMG, Hamburg, Germany) (Figure 12).

The patient wore the temporary for two weeks to get used to the new aesthetics, function and possible phonetic changes due to the reshaped palatal surface. During this time, modifications in shading, shape and function are possible so that the patient obtains an accurate impression of the final restoration and their wishes can be met.

The patient returned to the practice. She was very satisfied with the shape and function of the temporary so that the impression could be taken during this visit. In a first step, the shade of the final restoration was selected in co-operation with the patient using a Vita shade guide. The patient wanted the shade of the final crown to be slightly lighter than that of the temporary, so instead of A2, B2 was selected. The impression of the opposing arch was taken with StatusBlue.

Since the preparation had to be extended subgingivally for aesthetic reasons, retraction cords were placed in the sulcus and left there for several minutes before taking the impression. A precision dual-mix impression was then taken with Honigum-Heavy and Honigum-Light (DMG, Hamburg, Germany).

The temporary was repositioned and the impressions sent to the Laboratory. Figure 13 shows the final ceramic crown (Inceram, Vita, Bad Säckingen, Germany). It was tried-in and form and shade were discussed with the patient. The patient was very satisfied with the improved aesthetics so the crown was adhesively cemented. First, the prepared core was cleaned with a fluoride-free polishing paste. Then the crown to be cemented was cleaned with water spray and air, and saliva residue was removed with alcohol before the try-in. The core was also disinfected with alcohol.

In the next step, the dentine was pre-treated adhesively. Since Vitique (DMG, Hamburg, Germany) dual-curing cement was to be used, LuxaBond Total Etch (DMG, Hamburg, Germany), an adhesive system compatible with dual-curing cements, was selected. The appropriate enamel and dentine areas were first conditioned with 35 per cent phosphoric acid. Then the primer was applied, worked in and the excess removed by air. Subsequently, the bond-mix was applied. The crown was first conditioned with hydrofluoric acid and then silanised. The crown was filled with the luting cement in the shade selected beforehand, placed and correctly positioned (Figure 14). The Vitique luting cement system allows for precise shade selection in whichever cementation mode (light-curing or chemically curing) is used.

The try-in pastes can be combined with the respective variants and thus facilitate an exact visualisation of the final appearance of the restoration. In the next step, the excess cement was removed and the restoration light-cured for 10 seconds after which any fine cement surplus could still be removed. An Oxi-Stop gel was then applied and the cement light-cured once more.

Once the cement had fully cured, the entire crown area was checked for excess material which, if present, should be thoroughly removed. The interdental spaces were cleaned with dental floss. Figure 15 shows the final result directly after cementation. The shade of the crown matches that of the adjacent teeth perfectly. The oversized and, therefore, very dark-appearing interdental triangle was adjusted and the dark edge removed.

Conclusion

By means of simple techniques a satisfactory aesthetic result for the patient can be achieved. The placement of temporary crowns is an efficient tool in the dentist-patient communication process. It facilitates a very realistic imitation of the desired result, gives the patient an impression of his/her future smile early on, and enables the practitioner to meet the patient’s wishes and expectations in the final restoration very closely. Corrections of shape and shade during the wearing time of the temporary are easily possible, at any time, and quickly executed. The reshaping of the preparation lines and the choice of a highly aesthetic luting cement, offering selection of the desired shade beforehand, prevent negative effects of a mismatched cement colour on the final result. Thus, it is possible to achieve excellent aesthetic results even for such an aesthetically unf
avourable initial situation.

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