Maxillofacial Prosthetics - Definitive Obturators - Edentulous Patients

The fabrication of large obturator prostheses for edentulous patients will challenge the skill of the most experienced clinician.  Air leakage, poor stability and support, reduced denture bearing surfaces, will compromise adhesion, cohesion, and peripheral seal.  Consequently the contours of the defect must be used to maximize the retention, stability and support for the prosthesis.  This program addresses obturator design and details the methods of fabrication that are used by experienced clinicians to overcome these problems so that functional obturator prostheses can be fabricated for these patients.

Maxillofacial Prosthetics -Definitive Obturators – Edentulous Patients — Course Transcript

• 1. Definitive Obturators: Edentulous Patients John Beumer III, DDS,MS Distinguished professor emeritus UCLA School of Dentistry All rights reserved. This program of instruction is protected by copyright ©. No part of this program of instruction may be reproduced, or transmitted by any means, electronic, digital , photographic, mechanical etc., or by any information storage or retrieval system, without prior written permission from the authors .
• 2. Definitive Obturators: Edentulous Patients Objectives Prognostic factors Impression methods Maxillo-mandibular records Occlusion Delivery
• 3. Definitive Obuturators – Edentulous Maxillectomy Patients Restore the partition between the oral and nasal cavities so as to enable normal speech and swallowing Restore palatal contours Replace needed dentition and restore the occlusion Provide retention, stability, support for the complete denture obturator prosthesis Objectives:
• 4. Prognostic factors – Edentulous Patients Degree of movement . The more movement during function the poorer the prosthodontic prognosis. The degree of movement is dependent upon: Amount and contour of the remaining palate Availability of undercuts in the defect Availability of support areas within and peripheral to the defect
• 5. Prognostic factors – Edentulous Patients: Degree of Movement Axis of rotation for this defect is located along the medial palatal margin of the defect. The portion of the obturator at right angles and most distant from this axis will exhibit the greatest degree of motion .
• 6. Prognostic factors – Edentulous Patients: Degree of Movement In a posterior defect, when more of the premaxillary segment is retained, the axis of rotation moves posteriorly.
• 7. Prognostic factors – Edentulous Patients: Degree of Movement In anterior defects, the axis of rotation of the prosthesis is located along posterior margin of the defect. The anterior extension of the prosthesis will exhibit the greatest potential for movement.
• 8. Prognostic factors – Edentulous Patients: Degree of Movement With smaller defects, and particularly when a tuberosity segment is retained, considerably less movement of the prosthesis will be observed. Main issue in this patient will be retention
• 9. Prognostic factors – Edentulous Patients Denture bearing surfaces available for Support Residual palatal shelf Alveolar ridge contours Oral side of the soft palate Access to a skin lined lateral third of the orbital floor Skin lined base of the skull Presence of a remaining tuberosity on the defect side The more support available the better the prognosis
• 10. Prognostic factors – Edentulous Patients Means of Retention Defect side Lateral wall of the defect Undercut just superior to the skin graft mucosal junction Nasal side of the soft palate Nasal aperture Normal side Denture adhesive Osseointegrated implants The better the retention the better the prognosis .
• 11. Prognostic factors – Edentulous Patients Stability is affected by: Alveolar ridge contours Lateral wall of the defect (if skin lined) Medial wall of the defect (if lined with palatal mucosa) Use of osseointegrated implants The better the stability the better the prognosis.
• 12. Prognostic factors – Edentulous Patients Static vs dynamic defects If the posterior margin of the defect does not extend beyond the junction of the hard and soft palate, the defect will be relatively static – i.e. it will not change dramatically its shape during speech or swallowing or movement of the mandible. The prognosis for restoration of static defects is better than the prognosis for restoration of dynamic defects Static defect Dynamic defect
• 13. How much palatal shelf remains? The more the better the prognosis . Is the residual palatal shelf parallel to the occlusal plane. The more parallel to the plane the better the prognosis. Is there a residual tuberosity on the defect side? Presence of a tuberosity improves the prognosis. What is the height and contour of the residual alveolar process? Good alveolar ridge contours improves the prognosis. Residual palatal structures Good prognosis Poor prognosis Poor prognosis Good prognosis
• 14. Prognostic factors Stability-Is the lateral wall of the defect lined with skin? Is the resected portion of the palatal bone covered with palatal mucosa or a skin graft? Support-Is the lateral third of the orbital floor lined with skin? Can the obturator be extended superiorly to engage this area? Can the base of the skull be effectively engaged? Retention-How divergent is the lateral wall of the defect? Is there a significant undercut just superior to the skin graft mucosal junction? The more “yes” answers the better the prognosis Quality of the defect All these defects are favorable.
• 15. All four patients shown presented with poor quality defects. None are lined with skin, resulting in unfavorable contours and poor quality lining epithelium . Quality of the defect
• 16. Prognostic factors Neuromuscular control The successful patient is able to control the complete denture- obturator prosthesis, the mandibular denture and the bolus simultaneously. Few patients are able to manage these multiple tasks and will require the placement of osseointegrated implants for addition retention and stability.
• 17. Preliminary Impressions Key areas to record Residual palatal structures Lateral wall of the defect Oral side of the soft palate It is useful to inject impression material into key areas of the defect with a disposable syringe prior to seating the loaded tray.
• 18. Master impressions Custom tray fabrication Block out undesirable undercuts Medial Anterior and posterior Flow a thin layer of wax over the lateral wall of the defect Extend tray one cm onto the soft palate on the defect side Extend tray up the full height of the lateral wall and onto the posterior wall of the defect Do not block out the lateral wall undercut .
• 19. Master impressions Retention Posterior-lateral wall of the defect superior to the skin graft mucosal junction Nasal side of the soft palate Support Residual palatal structures Base of the skull Lateral portion of the floor of the orbit Stability Residual palatal structures Lateral wall of the defect
• 20. Extending the obturator prosthesis up the full height of the lateral wall of the defect facilitates retention .
• 21. Extension up the medial wall of the defect is limited by the amount of palatal mucosa and the need for normal nasal air flow.
• 22. Rentention-Secondary areas Nasal side of the soft palate Nasal aperture
• 23. Master impressions Master impression trays Note the extension onto the soft palate on the defect side The tray extends up the full height of the lateral wall of the defect Note the minimal medial wall extension Above the level of the soft palate
• 24. Border molding – Low fusing compounds are recommended because they provide more working time. Take care to avoid displacement of the tissues Begin by molding the unresected side. The extension up the medial wall is minimal. Excessive height in this area interferes with nasal air flow and offers no advantage in the anterior portion of the defect (oval). Proceed to the defect side. Mold the anterior two thirds of the lateral wall of the defect extending the impression up its full height. Contours below the skin graft mucosal junction (line) are dictated by lip contours, contours above by cheek contours.
• 25. Border molding Develop the contours of the posterior one third of the defect. Take particular care in developing the extensions associated with the skin graft mucosal junction. Avoid overextension posteriorly by bringing the mandible forward and laterally during border molding. If the lateral portion of the orbital floor or base of the skull is lined with skin attempt to extend the impression into these areas. Note the prominent undercut just above the skin graft mucosal junction in the posterior lateral portion of the defect.
• 26. Border molding In this patient the defect extended posteriorly all the way to pharyngeal wall. Note the imprint made by the medial side of the mandible in the lateral wall of the impression (arrows).
• 27. Cut back- Prior to completing the impression, approximately .5 mm of compound is removed from the surface. Before making the master impression the tissues in the defect must be thoroughly cleaned so that mucous accumulations and mucous crusts are removed.
• 28. Wash materials Polysulfide Recommended Thermoplastic waxes Generally not indicated for edentulous patients because of lack of occlusal stops They are, however, useful in making reline impressions in edentulous patients (because presence of occlusal stops) Corrected Impression
• 29. Corrected Impressions Polysulfide is preferred. Its viscosity and flow make it ideal for large maxillary defects. Before inserting the coated border molded tray, it is advisable to inject polysulfide material onto the lateral wall of the defect (arrows) and into appropriate undercuts. If the undercut is severe it is useful to inject medium body rubber base into the undercut and coat the rest of the tray with light body.
• 30. Corrected Impressions Defects extending into the velopharyneal area* These areas may be modified with a thermoplastic wax * In most patients these areas need to be refined at delivery. Soft palate at rest Soft palate elevated
• 31. Boxing the master impression and pouring the cast The master impression is boxed in the usual manner
• 32. Centric Relation Records Record bases and wax rims Minimal blockout should be used for the lateral wall of the defect. If excessive block out is employed the record base will be very unstable making it difficult to make accurate records.
• 33. Centric Relation Records Record bases and wax rims Minimal blockout should be used for the lateral wall of the defect. If excessive block out is employed the record base will be very unstable making it difficult to make accurate records.
• 34. Record bases Conventional Used when there is reasonable stability and support, either from the defect or from the residual palatal structures. Both these patients had sufficient stability and support to use conventional record bases. Making accurate and reproducible records is very difficult in these patients. The clinician must maintain control of both record bases simultaneously while making the centric relation record.
• 35. Record bases Processed are considered: When stability and support are deficient In large defects with little palatal shelf and poor alveolar ridge contours
• 36. Record bases Processed are considered: When stability and support are deficient In large defects with little palatal shelf and poor alveolar ridge contours This patient had a large defect and little palatal shelf remained. A processed record base was used to make centric relation records. The teeth were added later with autopolymerizing acrylic resin.
• 37. Vertical dimension of occlusion (VDO) Usual methods for determining the proper VDO are used VDO should only be reduced when patient exhibits severe trismus in order to permit easy access of the bolus Occlusal vertical dimension
• 38. Centric relation records Begins with a face bow record and mounting the maxillary cast Articulators modified to accept large maxillary casts are used Records are made in the customary fashion using record bases and wax rims Retain the mandibular record base with denture adhesive Prevent the maxillary record base from rotating into the defect while making the record.
• 39. a: Articulator capable of receiving large maxillary cast. b: Articulator modified to accept large maxillary casts. a b Articulators
• 40. Occlusal schemes Neutrocentric is preferred All teeth on the plane of occlusion. The maxillary lateral incisors may be lifted up off the plane to enhance esthetics. Lip plumpers may be added in selected patients with facial nerve weakness In this patient, a radical neck was performed on the side opposite the maxillectomy and the marginal mandibular nerve was resected- hence the lip plumper was added to the mandibular denture.
• 41. Try-in of Trial Denture and Obturator Verify : Centric relation record Vertical dimension of occlusion Esthetic display
• 42. Processing Heat cured methyl methacrylate Obturator portion should be hollow to reduce weight Silicones are avoided because of their susceptibility to deterioration in the presence of candida albicans Important characteristics and landmarks : a) Imprint of skin graft mucosal junction b) Imprint of the medial side of the ramus of the mandible c) Extension onto the residual soft palate (1 cm) d) Extension up the lateral wall of the defect
• 43. Pressure indicating paste – Used to delineate areas of tissue displacement on the unresected side Disclosing wax – Used for checking peripheral extensions and monitoring tissue displacement in the defect Clinical remount – Used to perfect the occlusion Delivery Steps
• 44. Identifying Areas of Tissue Displacement Pressure indicating paste Used primarily on the oral mucosa and on the unresected side Spray silicone releasing agent onto the PIP in patients with radiation induced xerostomia
• 45. Identifying areas of tissue displacement Disclosing wax Used in skin lined defects for patients who are xerostomic (PIP tends to stick to skin lined surfaces in such patients) The wax is placed into a disposable syringe, immersed in a water bath to soften the wax and then applied to the surface of the obturator. The restoration needs to remain in place for 1-2 minutes before removal and inspection.
• 46. Checking peripheral extensions Imprint of the ramus Peripheral extensions on the unresected side Periphery wax applied Pattern after removal Note displacement of tissues anteriorly A good pattern Tissue displacement in the posterior lateral area
• 47. Clinical Remount Perfect the occlusion with a new centric relation record We favor the neutrocentric scheme of occlusion using no anatomic posterior denture teeth and with no vertical overlap of the anterior teeth.
• 48. Completed obturator with ideal contours Lateral wall extension vertically for retention and stability Proper adaptation to the residual palatal shelf for support Engagement of the lateral third of the orbital floor for support (oval) Imprint of the medial side of the ramus Vertical extension- posterior medial portion of the defect to minimize leakage (oval) Maximum extensions for stability Proper extension (5-10mm) onto the oral side of the soft palate to prevent leakage (arrows)
• 49. Completed obturator with ideal contours Lateral wall extension vertically for retention and stability Coverage of skin lined skull base enhances support
• 50. Delivery and Followup Note the dramatic changes in soft tissue contour following insertion of the complete denture and obturator. This patient was also fitted with an orbital prosthesis.
• 51. Edentulous patients with partial palatectomy defects Retention may be difficult to achieve because of limited access to the defect In this patient, the obturator portion was processed in silicone in order engage bony undercuts and to facilitate retention. This silicone liner must be replaced yearly however .
• 52. Edentulous patients with partial palatectomy defects Defects extending into the middle third the of soft palate Challenge – Retention and leakage of fluids into the nasal passage during swallowing during palatal elevation. Soft palate at rest Soft palate elevated Osseointegrated implants can be used to provide retention To minimize leakage, the obturator should extend onto the nasal side of the residual soft palate (arrow).
• 53. Relatively small partial maxillectomy defect. It is difficult to engage such defects and implants are recommended to enhance retention. Nasal side of soft palate engaged to enhance seal (arrow). Edentulous patients with partial palatectomy defects Defects extending into the middle third the of soft palate Challenge – Retention and leakage of fluids into the nasal passage during swallowing during palatal elevation.
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