When a reasonable number of teeth remain, sufficient retention, stability and support can be garnered to effectively retain, stabilize and support the RPD and obturator prosthesis.  The residual dentition retains the prosthesis on the unresected side and the obturator engages the retentive areas of the defect to retain the prosthesis on the defect side. This program discusses RPD design concepts for these defects, and details the method of fabrication.  Several case studies to illustrate the basic principles are presented in the program.

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Maxillofacial Prosthetics – Definitive Obturators Edentulous Patients —  Course Transcript

  • 1. Definitive Obturators: Edentulous Patients John Beumer III, DDS,MS Distinguished professor emeritus UCLA School of DentistryAll rights reserved. This program of instruction is protected by copyright ©. Nopart of this program of instruction may be reproduced, or transmitted by anymeans, electronic, digital , photographic, mechanical etc., or by any informationstorage or retrieval system, without prior written permission from the authors.
  • 2. Definitive Obturators: Edentulous Patients v Objectives v Prognostic factors v Impression methods v Maxillo-mandibular records v Occlusion v Delivery
  • 3. Definitive Obuturators – Edentulous Maxillectomy PatientsObjectives: u Restore the partition between the oral and nasal cavities so as to enable normal speech and swallowing u Restore palatal contours u Replace needed dentition and restore the occlusion u Provide retention, stability, support for the complete denture obturator prosthesis
  • 4. Prognostic factors – Edentulous PatientsDegree of movement. The more movement duringfunction the poorer the prosthodontic prognosis. Thedegree of movement is dependent upon:l Amount and contour of the remaining palatel Availability of undercuts in the defectl Availability of support areas within and peripheral to the defect
  • 5. Prognostic factors – Edentulous PatientsAxis of rotation for this defect is located along the medialpalatal margin of the defect. The portion of the obturator atright angles and most distant from this axis will exhibit thegreatest 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 MovementIn anterior defects, the axis of rotation of the prosthesisis located along posterior margin of the defect. Theanterior extension of the prosthesis will exhibit thegreatest 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 PatientsDenture bearing surfaces available for Support l Residual palatal shelf l Alveolar ridge contours l Oral side of the soft palate l Access to a skin lined lateral third of the orbital floor l Skin lined base of the skull l Presence of a remaining tuberosity on the defect sideThe more support availablethe better the prognosis
  • 10. Prognostic factors – Edentulous PatientsMeans of RetentionDefect side Lateral wall of the defect Undercut just superior to the skin graft mucosal junction Nasal side of the soft palate Nasal apertureNormal side Denture adhesive Osseointegrated implants The better the retention the better the prognosis.
  • 11. Prognostic factors – Edentulous PatientsStability is affected by: l Alveolar ridge contours l Lateral wall of the defect (if skin lined) l Medial wall of the defect (if lined with palatal mucosa) l Use of osseointegrated implants The better the stability the better the prognosis.
  • 12. Prognostic factors – Edentulous Patients Static vs dynamic defects v 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 – Static defect i.e. it will not change dramatically its shape during speech or swallowing or movement of the mandible. v The prognosis for restoration of static defects is better than the prognosis for restoration of dynamic defectsDynamic defect
  • 13. Prognostic factors Residual palatal structures l How much palatal shelf remains? The more the better the prognosis. l Is the residual palatal shelf parallel to the occlusal plane. The more parallel to the plane the better the prognosis. Good prognosis l Is there a residual tuberosity on the defect side? Presence of a tuberosity improves the prognosis. l What is the height and contour of the residual alveolar process? Good alveolar ridge contours improves the prognosis.Poor prognosis Poor prognosis Good prognosis
  • 14. Prognostic factors Quality of the defect v 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? v 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? v 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”All these answers the betterdefects are the prognosisfavorable.
  • 15. Prognostic factors Quality of the defect All four patients shown presented with poor quality defects. None are lined with skin, resulting in unfavorable contours and poor quality lining epithelium.
  • 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 andwill require the placement of osseointegrated implants.
  • 17. Impressions Preliminary Impressions Key areas to record v Residual palatal structures v Lateral wall of the defect v Oral side of the soft palateIt is useful to inject impression material into key areas of thedefect with a disposable syringe prior to seating the loaded tray.
  • 18. Impressions Master impressions l 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 impressionsRetention Ø Posterior-lateral wall of the defect superior to the skin graft mucosal junction Ø Nasal side of the soft palateSupport Ø Residual palatal structures Ø Base of the skull Ø Lateral portion of the floor of the orbitStability Ø Residual palatal structures Ø Lateral wall of the defect
  • 20. Master impressions-Extension into the defect Extension up the full height of the lateral wall of the defect facilitates retention. Extension up the medial wall of the defect is limited by the amount of palatal mucosa and the need for normal nasal air flow.
  • 21. Master impressionsRentention-Secondary areas l Nasal side of the soft palate Nasal aperture
  • 22. Master impressions Above the level of the soft palateMaster 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
  • 23. Master impressions l 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.
  • 24. 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 mucosaljunction in the posterior lateral portion of the defect.
  • 25. Master impressions 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).
  • 26. Border moldingl Combined hard – soft palate defect
  • 27. Master impressions Cut back- Prior to completing the impression, approximately .5 mm of compound is removed from the surface.Before making the master impression thetissues in the defect must be thoroughlycleaned so that mucous accumulationsand mucous crusts are removed.
  • 28. Master impressionsWash materials l Polysulfide l Recommended l Thermoplastic waxes l Generally not indicated for edentulous patients because of lack of occlusal stops l They are, however, useful in making reline impressions in edentulous patients (because presence of occlusal stops)
  • 29. Master 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 mediumbody rubber base into the undercut and coat therest of the tray with light body.
  • 30. Master impressions Defects extending into the velopharyneal area* l These areas may be modified with a thermoplastic waxSoft palate at restSoft palate elevated *In most patients these areas need to be refined at delivery.
  • 31. Master impressionsBoxing the master impression and pouring the castl The master impression is boxed in the usual manner
  • 32. Centric Relation RecordsRecord bases and wax rimsv 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 rimsMinimal blockout shouldbe used for the lateralwall of the defect. Ifexcessive block out isemployed the recordbase will be veryunstable making itdifficult to make accuraterecords.
  • 34. Conventional Record bases l 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 basesl Processed are considered: l When stability and support are deficient l 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.
  • 36. Vertical dimension of occlusion (VDO)l Usual methods for determining the proper VDO are usedl VDO should only be reduced when patient exhibits severe trismus in order to permit easy access of the bolus Occlusal vertical dimension
  • 37. Centric relation recordsv Begins with a face bow record and mounting the maxillary castv Articulators modified to accept large maxillary casts are usedv Records are made in the customary fashion using record bases and wax rims
  • 38. Articulatorsa b a: Articulator capable of receiving large maxillary cast. b: Articulator modified to accept large maxillary casts.
  • 39. Occlusal schemesNeutrocentric is preferred l 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.
  • 40. Try-in of Trial Denture and Obturator Verify: Ø Centric relation record Ø Vertical dimension of occlusion Ø Esthetic display
  • 41. Processingl Heat cured methyl methacrylatel Obturator portion should be hollow to reduce weightl 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
  • 42. Delivery Stepsv Pressure indicating paste – Used to delineate areas of tissue displacement on the unresected sidev Disclosing wax – Used for checking peripheral extensions and monitoring tissue displacement in the defectv Clinical remount – Used to perfect the occlusion
  • 43. Identifying Areas of Tissue DisplacementPressure indicating paste l Used primarily on the oral mucosa and on the unresected side l Spray silicone releasing agent onto the PIP in patients with radiation induced xerostomia
  • 44. Identifying areas of tissue displacementDisclosing wax v 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.
  • 45. Checking peripheral extensions v Imprint of the ramus v Peripheral extensions on the unresected sidePeriphery wax applied Pattern after removal Note displacement of tissues anteriorly Tissue displacement in the posterior lateral area A good pattern
  • 46. Clinical Remountl 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.
  • 47. Completed obturator with ideal contoursLateral wall extension Vertical extension- posteriorvertically for retention medial portion of the defect to minimize leakage (oval) Maximumand stability extensions for stability Proper adaptation to the residual palatal shelf forEngagement of the support Imprint of thelateral third of the medial side oforbital floor for the ramussupport (oval) Proper extension (5-10mm) onto the oral side of the soft palate to prevent leakage (arrows)
  • 48. Completed obturator with ideal contours Lateral wall extension vertically for retention and stabilityCoverage of skin lined skullbase enhances support
  • 49. Delivery and FollowupNote the dramatic changes in softtissue contour following insertion of thecomplete denture and obturator. Thispatient was also fitted with an orbitalprosthesis.
  • 50. Edentulous patients with partial palatectomy defects l Retention may be difficult to achieve because of limited access to the defectIn this patient, the obturator portion was processed in silicone inorder engage bony undercuts and to facilitate retention. Thissilicone liner must be replaced yearly however.
  • 51. Edentulous patients with partial palatectomy defectsDefects extending into the middle third the of soft palate l 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).
  • 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.v Relatively small partial maxillectomy defect. It is difficult to engage such defects and implants are recommended to enhance retention.v Nasal side of soft palate engaged to enhance seal