Uneven alignment of the natural teeth is a common clinical occurrence, which may be caused by eruption, wear, or drifting of teeth. A normal occlusal plane, such as with a curve of Monson, , is a primary objective of restorative procedures and facilitates natural mandibular movements and mastication. Devices and techniques have been described to evaluate and correct the occlusal plane, including the Broderick occlusal plane analyzer, the Yurkstas metal occlusal template, and the custom made occlusal plane template (OPT). , The OPT can be used to detect an uneven occlusal plane on the diagnostic cast or directly in the mouth. The present technique demonstrates a modification of the OPT by attaching abrasive paper to the convex surface of the OPT to facilitate trimming of the uneven surfaces on a diagnostic cast to identify potential occlusal areas for modification in the mouth.
The procedure is demonstrated on a mandibular diagnostic cast of a patient for whom a maxillary single removable complete denture was planned.
Fabricate a custom made OPT as described by Muley et al and Foong and Patil ( Fig. 1 A). Obtain a volleyball (Mikasa MVA310; Mikasa Sports) with a diameter of approximately 20.7 cm (8.1 inches). Note that the size closely corresponds to the Monson sphere (with a diameter of 8 inches). , Adapt modeling wax (Modelling Wax; Vertex Dental) (or boxing wax) (in a similar manner to that of boxing of an impression) on the surface of the volleyball to create a circular box of approximately 10 cm in diameter. Pour Type III dental stone (Dental Stone; Pro Dental) into the wax box adapted on the surface of the volleyball. After setting, separate the cast and smooth the surface to prepare a concave cast-form. Adapt a 1.5-mm-thick, hard, thermoplastic sheet (Duran; Scheu Dental Technology) onto the cast-form in a vacuum forming machine (Ministar; Scheu) ( Fig. 1 A). , Keep the original circular shape of the OPT and do not further shape it according to the U-shape arch. Alternately procure a stock metal occlusal plane template (Yurkstas) if available.
Procure an abrasive paper (Silicone carbide waterproof abrasive paper electro-coated; Eagle sandpaper) and cut it in a circular manner according to the size of the circular OPT (10 cm diameter).
Cut along the radius of the circular shaped abrasive paper and stick it on the convex surface of the OPT with a quick-setting cyanoacrylate adhesive (Super Glue; TEX-YEAR Industries Inc) to make a self-grinding OPT ( Fig. 1 B, 1C ). Note that the single cut made along the radius helps to accommodate the convexity of the OPT. For the maxillary cast to modify, the abrasive paper can be glued to the concave surface of the OPT.
Identify a minimum of 4 points: distobuccal cusp tips of the mandibular right and left first molars and the cusp tips of the mandibular canines on the diagnostic cast. , Note that, in situations where any of these 4 cusp tips are not in even occlusal plane, they need to be modified before grinding. If the identified cusp tips are damaged or do not occlude, the cusp tips can be built-up with dental stone, and, if the tip is supra-erupted, it can be trimmed to ensure the identified 4 points are in an even occlusal plane to provide a plane of reference.
Apply a thin layer of a quick-setting cyanoacrylate adhesive (Super Glue; Tex Year Industries Inc) on these identified cusp tips to protect them from accidental wear during grinding, as these points are considered to form a plane of reference and as a part of a Monson curve.
Paint the occlusal and axial surfaces of all teeth on the cast with student watercolors (Camlin) ( Fig. 2 A). Select a color that contrasts with the cast.
Use the self-grinding OPT to grind the occlusal surfaces ( Fig. 2 B). Continue grinding until the template touches all 4 identified cusp-tips. Note that, the trimmed surface areas will be easily identifiable on the occlusal surfaces of the cast ( Fig. 2 C).
Use this modified cast to identify the corresponding areas in mouth for tooth modification to achieve an even occlusal plane. Proceed to adjust the teeth in the mouth in a conventional manner by considering the amount of tooth reduction (within enamel or superficial dentin). ,
Alternately, adapt a vacuum-formed clear template on the modified cast and cut the template at the level of the trimmed tooth surfaces with a scalpel blade as described by Tan. Mark the margins of the cuts on the template and place it in the mouth. Note that the portions of natural teeth protrude through the template, which can be easily identified for grinding.
1. Foong K.W., Patil P.G.: Fabrication of maxillary single complete denture in a patient with deranged mandibular occlusal plane: a case report. Saudi Dent J 2019; 31: pp. 148-154.
2. The glossary of prosthodontic terms. Ninth edition. J Prosthet Dent 2017; 117: pp. e1-105.
3. Monson G.S.: Occlusion as applied to crown and bridgework. J Nat Dent Assoc 1920; 7: pp. 399-413.
4. Bedia S.V., Dange S.P., Khalikar A.N.: Determination of the occlusal plane using a custom-made occlusal plane analyzer: a clinical report. J Prosthet Dent 2007; 98: pp. 348-352.
5. Yurkstas A.A.: Single dentures.Sharry J.J.Complete denture prosthodontics.1968.McGraw-HillNew York:pp. 300.
6. Muley B.Y., Patil P.G., Khalikar A.N., Puri S.B.: Simple technique to fabricate custom made occlusal plane template. J Indian Prosthodont Soc 2014; 14: pp. S334-S336.
7. Tan H.K.: A preparation guide for modifying the mandibular teeth before making a maxillary single complete denture. J Prosthet Dent 1997; 77: pp. 321-322.