BEHIND THE SCENES
P
remature contact in restorative and prosthodontic work is a critical concern for every dentist. Single crowns (regardless of material), bridge restorations and implant structure present the highest prevalence of premature contacts during trial fitting. This cannot be fully attributed to the patient’s perception as this is a subjective assessment: The use of occlusion test materials, which demonstrates reliable objective evidence, is essential to address this concern. Ill-fitting prosthesis means numerous laboratory interventions,
Protocol” (Figure 2: http://www. bausch.fm/bauschweb/dwnld/ ShimstockProtokoll.pdf) before starting the preparation and as a supplement to the occlusion test. In this respect, it is important that the test be made when the patient is in maximum intercuspation. According to the definition of the DGZMK, maximum intercuspation is solely determined by the occlusion in largely preserved supporting areas and stable intercuspation. In maximum intercuspation, the position of the mandible is defined in relation to the upper jaw in all three dimensions.
It is recommended to use identical occlusion test materials in the dental practice and laboratory, as this will lead to better results.
Using S h i m s t o c k F i l m for Achieving Precise Occlusion by Meltem Inanmisik, dentist
which could include several requests for modification or grinding in the patient’s mouth. In turn, this lengthens the duration of the treatment and greatly affects the occlusal surface contouring of the initial prosthetic work. Imperfect handling in the clinic or laboratory can result to additional inaccuracies, thereby delaying the installation of the final restoration.
Fig. 1
The occlusion protocol and the Shimstock protocol recorded by the dentist will be forwarded to the laboratory (Figure 4). These protocols form the basis for the lab to check occlusal contacts after articulation.
1. 2. 3. 4. 5.
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The recorded Shimstock Protocol (Figure 3) and the dental chart including the occlusal contact points are precise, diagnostic tools for prosthodontics. Fig. 4
Causes of “very high” indirect restorations (premature contacts) No occlusion test prior to preparation Insufficient vertical preparation Deficient impression taking Incorrect impression storage Patient not in an upright sitting position – It is a MUST that the patient sits upright. 6. Defective or missing jaw relation 7. Change of tooth position during temporary restorations 8. Incorrect mixing ratio of impression material 9. Incorrect model construction 10. Other faulty materials 11. Defective opposing jaw model because of suboptimal impression/ storage/model construction In this context, it would be advisable for the dentist to create a “Shimstock
Fig. 3
Fig. 5: Bausch Arti-Fol metallic, Shimstock-Film BK 38 (12µ uncoated) Fig. 2
Handling of Arti-Fol metallic (BK38) Shimstock film At habitual bite, it should be possible to pull the foil through (Figure 1).
A Shimstock Protocol can be created using the Bausch Arti-Fol metallic BK 38 (Figure 5) or Arti-Fol metallic BK 35 (Figure 6). The base material of these films is a metallised polyester film DENTAL ASIA NOVEMBER / DECEMBER 2015