An altered cast procedure to improve tissue support

altered cast technique

1. An altered cast procedure to improve tissue support for removable partial denture Journal of Contemporary Clinical Dentistry Chandrashekar Sajjan Department of Prosthodontics, AME's Dental College, Hospital & Research Center, Raichur, India Presented by : Dr. Bhupendra Rizal MDS 2 nd year

2. CONTENTS Introduction Case report Discussion Conclusion

3. INTRODUCTION The most important consideration in designing a free-end saddles/distal extension removable partial denture, or CPD, for optimum function is as DeVan stated “ the perpetual preservation of that which remains, and not the meticulous replacement of that which has been lost.” Cast partial denture made using the altered cast impression technique helps create an environment in which the teeth and the edentulous tissues support the base as compatibly as possible. The result is a potentially more stable RPD that improves the support for the occlusal relationship of the opposing dentition and the RPD restoration.

4. What is altered cast technique? Also known as corrected cast or slip cast technique . It is mainly a modification of functional impression through laboratory procedure. Basically, the altered-cast procedure applies some of the principles of impressions for complete dentures to the fabrication of the tissue surfaces of extension removable partial dentures. AN ALTERED-CAST PROCEDURE TO IMPROVE TISSUE SUPPORT FOR REMOVABLE PARTIAL DENTURES ROBERT J. LEUPOLD, AND FRANK J. KRATOCHVIL U. S. Naval Dental School, National Naval Medical Center , Bethesda, Md.

5. The refined impression of the edentulous tissue surfaces is made after the metal casting has been completed and is used to alter the edentulous areas of the master cast. The resultant cast accurately reproduces the supporting tissues in a form that provides the correct denture base extension and favorable physiologic support when the denture is in its fully seated position. AN ALTERED-CAST PROCEDURE TO IMPROVE TISSUE SUPPORT FOR REMOVABLE PARTIAL DENTURES ROBERT J. LEUPOLD, AND FRANK J. KRATOCHVIL U. S. Naval Dental School, National Naval Medical Center , Bethesda, Md.

6. This technique has the potential benefits of reducing the number of postoperative visits, Preserving the residual ridges, Improving stress distribution, Decreasing food impaction, and Decreasing the torquing of abutment teeth. All of which lead to increased patient satisfaction.

7. Becker and colleagues critically reviewed the evolution of RPD and outlined six principles of RPD design. These principles include : a rigid major connector, multiple positive rest seats, mesial rests, parallel guide planes, the I-bar clasp design and the altered cast technique.

8. CASE REPORT 1

9. Mandibular edentulous arch with distal extension Maxillary edentulous arch with partial missing teeth

10. Preliminary impressions were made with irreversible hydrocolloid and study casts were obtained. The study casts were placed on a surveyor for examination and design of the cast framework. Mouth preparation was done and final impression of maxillary and mandibular arch were made with medium bodied elastomeric impression material.

11. Secondary casts obtained were placed on a surveyor for examination and design of the cast framework Master casts were duplicated, refractory cast were obtained, and the design was transferred from the master cast to the refractory cast. Investing and casting was completed.

12. Mandibular metal framework Maxillary metal framework

13. Mandibular metal try in Maxillary metal try in

14. An acrylic resin custom tray attached to the mandibular metal framework

15. Border molded tray for the desired extension Final impression made using zinc oxide eugenol. impression paste

16. Cast with two saw cuts perpendicular to each other on either side of saddle The cut surface of the cast with grooves

17. Seating of the framework on the cast with sticky wax Final impression with beading and boxing

18. An altered cast

19. Occlusal view of mandibular cast partial denture Anterior view of cast partial denture

20. CONCLUSION A favorably extended base will provide stimulation to the underlying bone and distribute forces uniformly. The altered cast technique allows the ridge, recorded in functional form, to be related to the teeth so that when the prosthesis is seated, it derives support simultaneously from the teeth and the denture base. This technique produces the following results : Remarkable stability in the denture base region of distal extension removable partial dentures. A positive occlusion which will be maintained for long periods of time. Reduced stress on abutment teeth from unfavorable forces. Reduced numbers of postinsertion adjustments.

21. CASE REPORT 2 Altered cast technique for management of large maxillary defects The Journal of Indian Prosthodontic Society / July 2009 / Vol 9 / Issue 3 G. N. Anandakrishna Department of Prosthodontics, MS Ramaiah Dental College and Hospital, MSR Nagar, MSRIT Post, Bangalore-560 054, India.

22. A 58-year-old male patient reported to the department of prosthodontics with a history of carcinoma of the maxillary sinus five years ago. Unilateral maxillectomy defect on the left side extending from the central incisor to the soft palate

23. Ill fitting interim acrylic obturator

24. A preliminary impression was made with irreversible hydrocolloid Reline impression is made with light viscosity addition silicone material to make an accurate impression of the defect

25. the altered cast a denture base is fabricated, Jaw relation is done for CR and tooth setup

26. The acrylized denture comprising of the intaglio surface of the defect side and teeth

27. The final obturator is evaluated for the adequacy of fit, esthetics and function

28. DISCUSSION Obturators and facial prostheses are important not only in rehabilitation and esthetics, but also in patient re-socialization. The level of reintegration is directly related to the degree of satisfaction with rehabilitation. In literature very little is written about usage of the altered cast technique for fabrication of maxillary obturator using a two stage impression technique. Altered cast technique is typically used as a special procedure for removable of partial denture in distal extension situations to equate the pressure between the teeth and the edentulous space.

29. When adapted to make impressions for large maxillary defects, it provides distinct advantage since the framework seating makes verification of jaw relation and the trial procedure more accurate. The recording of the defect is relatively easy as the tray size is greatly reduced by using the framework to carry the impression material. Path of insertion and removal can also be determined. The altered cast technique as an alternative to conventional impression making in maxillofacial defects has not been discussed in literature. Hence description of this technique may be quite useful in restoration of large maxillary defects.

30. CONCLUSION Altered cast technique is one of the improvisations that can be made while making an obturator for large maxillary defects. It not only improves the impression making and fabrication easier but also provides comfort to the patient by not trying to stretch open the mouth during impression procedure.

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