Maxillofacial Prosthetics - Implant Retained Maxillary Obturators

Obturator prostheses fabricated for patients with large palatal defects consistently restore speech and swallowing to normal levels, but lack sufficient stability, retention and support to restore mastication to presurgical levels.  The presence of implants however, dramatically changes this situation and most patients are able to chew effectively with implant retained maxillary obturators.  This program describes the evolution of implant connected bar designs that have evolved at UCLA during the last 20 years based on our research and clinical experience.

Maxillofacial Prosthetics – Implant Retained Maxillary Obturators — Course Transcript

• 1. 17. Implant Retained Maxillary Obturators
• 2. Implant retained maxillary obturators Background Early failures Implant failure rates Bone loss Implant overload Evolution of tissue bar design Photoelastic analysis Implant sites Premaxilla Posterior alveolar ridge Maxillary tuberosity Zygoma Case reports Clinical data
• 3. Implant Retained Prostheses for Maxillary Defects l Maxillectomy defects – Challenge in edentulous patients: Stability, retention and support are compromised Implants can dramatically improve the stability and retention of the complete denture with obturator. Support must be provided by the residual palatal structures (palatal shelf, The forces of atmospheric alveolar ridge pressure, and adhesion and etc.) cohesion are no longer sufficient to keep the prosthesis in position
• 4. Retention is critical because without it:v Speech is hypernasalv Leakage of bolus and fluids into the nose occursv Mastication efficiency is compromised because the tongue is preoccupied with keeping the obturator is position
• 5. Masticatory Performance N=5 * *% performance 50.0 46.2 40.5 37.5 Defect 25.0 Intact 15.6 North 12.5 8.8 6.2 8.2 6.6 8.1 0 Entry Post-Surgery Post-CP Post-IP Garret et al, 2008
• 6. Retention is effective and the RPD design can be conservative if: The lateral wall of the defect is lined with skin A reasonable number of healthy teeth remain
• 7. Removable Partial Denture and ObturatorRetention: Provided by the lateral wall ofthe defect (oval) and the dentitionStability: Provided by the dentition, andthe residual palatal structuresSupport: Provided by the remainingdentition, residual palatal shelf andalveolar process
• 8. Value of Implants• Retention provided onthe unresected side• Stability improvedwhich enhances retentionon the defect side(maintains properpositioning of theobturator in the defect) Result: Speech and swallowing restored Well retained prosthesis enables the patient’s tongue to position the bolus on the unresected side where residual denture bearing surfaces can provide support during mastication. Mastication is thereby restored to predisease levels of performance.
• 9. Early efforts yielded disappointing results Bone loss around the implants What was the explanation for the bone loss?Most bone loss was found around implants placed in thepremaxilla and the least around solitary implants in the tuberosity.
• 10. Preliminary data –Success Rates Implant sites Number of implants placed Success Placed Uncovered Buried Failed % Anterior maxilla 26 *5 21 1 2 85.7 Posterior maxilla 31 *8 14 **9 2 4 57.1 Tuberosity 17 14 **3 0 6 57.1 Pterygoid plates 4 4 **3 1 0 0 Zygoma 4 4 2 0 50 Palate 3 0 **3 0 0 – Total 85 *13 54 **18 6 12 66.7At first glance this data is not particularly surprising. However,the degree of bone loss around implants placed in thepremaxilla was disturbing (Roumanas et al, 1997).
• 11. Preliminary Data – UCLA Obturator Implant – Bone Levels: Implants in Function Minimum Moderate Severe Anterior Maxilla 5 4 8 Post. Maxilla 8 2 0 Tuberosity 8 1 1 A high percentage of implants placed in the anterior maxilla demonstrated moderate to severe bone loss while few of those under function in the posterior maxilla or the maxillary tuberosity demonstrated moderate to severe bone loss.What are the possible explanations for this difference?
• 12. Most implants in the tuberosity or posterior“0” ring attachments enabled the prosthesis to rotate in justabout any plane. Result: Nonaxial forces delivered to the implant were minimized.
• 13. Tissue bar designs used in the premaxilla during this period were implant supported designs The design shown was commonly used in our clinic in the late 1980’s. Note the Hader bar extension in the distal extension area (arrow). In this position the Hader segment is performing like a nonresilient attachment. After 18 months of use, note the bone loss around the implants, particularly the distal implant adjacent to the cantilever. Our preliminary judgment was that the bone loss was secondary to implant overload.
• 14. Implant Overload and Bone Resorption Mechanisms of Implant Failure*Excessive occlusal loadsResulting microdamage(fractures, cracks, anddelaminations)Resorption remodelingresponse of boneIncreased porosity ofbone in the interfacezone secondary toremodelingVicious cycle ofcontinued loading, moremicrodamage, moreporosity until failure Hoshaw et al, 1994; Brunski et al, 2000; Myamoto et al, 2008)
• 15. Eliminate Implant Overload inEdentulous Maxillectomy Patients Challenge: Develop implant assisted tissue bar designs specifically tailored for maxillectomy defects
• 16. Eliminating Implant Overload inEdentulous Maxillectomy Patients Goal:Create implant assisted designs. They should bedesigned to facilitate retention and stability. They should not be the sole means of support. Occlusal forces should be directed along the long axis of the implants.
• 17. Implant retained prostheses for maxillary defects Implants are most predictable when the occlusal loads are directed along the long axis of the implants (A). Load magnification occurs when loads are applied at an angle to the long axis (B). Load magnification can lead to implant overload and resorptive remodeling response of the investing bone. A B Initial challenge: Design a tissue bar that directed occlusal loads axially.
• 18. Photoelastic AnalysisPurpose: To identify implant assistedtissue bar designs for use inmaxillectomy defects which provideadequate retention and best directocclusal forces along the long axis ofthe implants.
• 19. Photoelastic analysis*l Several designs were tested including: Hader bar Bar with ERA attachments with and without rests Bar with “0” ring attachments *Davis B, et al,1995
• 20. Photoelastic analysis Tissue bars for maxillectomy defects Results “0” Ring bar design Hader bar designThe “0” ring type attachment resulted in the most favorablestress distribution and the Hader bar type resulted in the leastfavorable stress distribution.
• 21. Photoelastic analysis – Results Tissue bar designsBest combination of retention and stress distribution wasassociated with the tissue bar with ERA type resilientattachments on either side with occlusal rests atop the bar(arrows). Occlusal rests
• 22. Maxillectomy defects – Tissue bar designs Occlusal rests ERAERA MetalERA attachments are connected to Substructureeach side and occlusal rests placedon top of the tissue bar.The rests control the axis of rotationand allow the ERA attachments tofunction vertically as designed.
• 23. Maxillectomy Defects – Tissue Bar Designs RestsThe metal substructure (arrow) only engages thebar via the rests and the ERA attachments. Thisdesign minimizes the lateral torquing forcesdelivered to the implants when occlusal forces areapplied and reduces the risk of implant overload.
• 24. Maxillectomy Defects – Tissue Bar DesignsSince we began using this design in themid 1990’s bone loss around the implantshas been almost totally eliminated.
• 25. Potential Implant Sitesl Residual premaxillary segmentl Residual posterior alveolar ridge Sinus lift and graftl Maxillary tuberosityl Zygoma Normal side Defect side
• 26. Premaxillary segment Best bone sites although some may have horizontal deficiencies requiring onlay grafts Principal problem: Limited anterior – posterior spread ie, linear configurations Retention bar designs must be implant assisted Rentention bars with ERA attachments and occlusal rests are the preferred design
• 27. Maxillary tuberosityPoor quality bone – Fifty per cent of the implants withthe original machined surfaces placed failed toosseointegrate. The new microrough surfaces have hadvery little impact on these figures.This site used only when no others are available“0” Ring attachments are favored because they permitmultiple axis of rotation
• 28. Posterior alveolar ridgeProblems Limited bone in most patients because of pneumatized sinuses. Few patients present with sufficient bone over the sinus. In these patients implants 10 mm in length were placed. Rests
• 29. Posterior alveolar ridge a bTwo tissue bar designs for implants positioned in the posterioralveolus. One (a) uses ERA attachments with occlusal rests oneither side of the bar. The other (b) uses Hader atttachmentslined up parallel to the access of rotation in and out defect.
• 30. Posterior alveolar ridge Sinus lift and graft Predictable in patients with radical maxillectomy defects except when the the sinus region has been heavily irradiated.
• 31. Zygoma Implants in the zygoma on the resected side are not recommended Difficult hygiene access Implants must be placed in unfavorable angulations re: occlusal plane. High probability of implant failureA retentive skin lined defect,such as this one, provides justas much retention as implants,particularly if magneticattachments are used
• 32. Implants in the zygomaThe resected side – Problems The implants are located high in the defect, making oral hygiene difficult Implants are parallel to the plane of occlusion Consequently, only magnetic attachments can be used. The gains in retention with this type of attachment system are not significant
• 33. Implants in the zygoma The resected side – Problems Delivery 6 months post deliveryDifficult hygiene access lead to accumulation of plague.Result:Peri-implantitis, tissue hypertrophy, bone loss andeventually loss of the implants
• 34. Total Palatectomy Defectsv Conventional length vs zygomaticus implants
• 35. Total Palatectomy Defectsv Conventional length vs zygomaticus implants v Total palatectomy secondary to mucormycosis v Skin graft at revision surgery v Two 10mm dental implants placed in each zygoma Courtesy R. Wallace
• 36. Prosthetic ConsiderationsFindings: v Bilateral total maxillectomy, all nasal bones removed, skin graft v Collapsed midfacial contours v 4 Max 3.75mm x 10mm dental implants in zygomatic bones, severe misangulation v Opposing natural dentition v Catawampus occlusal plane
• 37. Prosthetic Considerationsl Treatment Plan: l 2 cast implant tissue bars w/ magnetic attachments l Maxillary implant & soft palate retained complete denture obturator l Surgical release of anterior scar band l Maxillary obturator hard reline
• 38. Total Palatectomy Defects
• 39. Fixture Level Impression
• 40. Lateral View
• 41. Tissue Bar Design
• 42. Soldered Connectors
• 43. Altered Cast Functional Impression
• 44. Altered Cast Functional Impression
• 45. Artificial Tooth Arrangement & Wax – Up
• 46. Definitive Prosthesis
• 47. Definitive Treatment
• 48. Definitive Treatment
• 49. Definitive Treatment
• 50. Post-Treatment Frontal View
• 51. Zygomaticus implants Best suited for total palatectomy defectsIssues l Radiation l Hygiene l Long term survivabilty Courtesy A. Sharma
• 52. Immediate placement upon tumor resection Useful in edentulous patients Reserved for patients with localized tumors
• 53. Immediate placement upon tumor resection Advised even if the patients scheduled to receive postoperative radiation therapy because of the dose enhancement effect at the bone implant interface.
• 54. Implant Assisted Maxillary Obturators Case reportPatient is status post total palatectomy for adenoidcysticcarcinoma. Three implants placed in maxillary tuberosity.Note excellent skin lined undercut in left lateral wall of defect
• 55. Case report Tissue bar design used. The anterior Hader bar attachment (oval) was oriented parallel to the estimated axis of rotation. The posterior Hader segment (arrow) was designed to facilitate stability.The anteriorimplant failed tointegrate andwas removed.
• 56. Case reportThe finished obturator prosthesis The posterior Hader clip was made to be nonretentive Note the nasal aperture extensionTwo and one half years after delivery, anterior implant failed.Failure was preceded by steady, progressive bone loss. Loss wasprobably caused by long lever arm of prosthesis leading toimplant overload.
• 57. Case report “0” ring secured to remaining implant. Eight years later implant is still present with no significant bone loss. Why? The “0” ring permits rotation around just about any axis, whereas previous design permitted rotation around just one axis.Result: The magnitude of lateral torquing forces deliveredto the implant is minimized with the “0” ring attachment.
• 58. Total palatectomy restored using implants Speech and swallowing were restored.Retention: The implant The lateral wall of the defect The nasal aperture extension
• 59. Case report-Soft Palate Defect The completed prosthesis in The completed position. complete denture and obturator Retention was excellent and speech, mastication, and swallowing were restored.
• 60. Case Report – Combined Hard and Soft Palate DefectThis patient is S/P maxillectomy. The soft palate has also beenresected. The anterior teeth were lost secondary to periodontal boneloss. Implants were placed in the residual premaxillary segment.
• 61. Case Report – Hard and Soft Palate DefectThe tissue bar is tried must fit passively.Rests (arrows) are milled into the bar between the implants.Occlusal forces are directed through the rests
• 62. Case Report – Hard and Soft Palate Defect Rests ERAAttachments Note the metal substructure incorporated within the finished prosthesis. It contains the ERA attachments and the occlusal rests.
• 63. Case ReportNote contours of obturator.Extension into velopharyngealarea is about 10 mm in height.Note prominent gingival rollposteriorly on defect side todeflect the cheek away from thbiting surfacesProsthesis in position. Noteelevation of right lateral incisorand cuspid so as to follow lip line.
• 64. Implants in edentulous maxillectomy patients Patients Number of implants Success Treated placed uncovered buried failed %Irradiated 13 50 29 3 10 55.2Non-Irradiated 10 35 25 3 2 80.0Totals 23 85 54 6 12 66.7 Failures in the irradiated group tend to be late, after the implants have been loaded.
• 65. Masticatory Performance N=5 50.0 * * 46.2% performance 40.5 37.5 Defect 25.0 Intact 15.6 North 12.5 8.8 6.2 8.2 6.6 8.1 0 Entry Post-Surgery Post-CP Post-IP Garret et al, 2008
• 66. Implants in Maxillectomy Defects Lessons LearnedImplants should not be the sole means ofretention, stability and supportThe residual palatal structures should beengaged effectivelyThe defect should be used to maximumadvantage to retain, stabilize and supportthe obturator prosthesis
• 67. Challenge in Edentulous Maxillectomy Defects:For the prosthodontist: Develop tissue bar designs for radical maxillectomy defects that: Account for the multiple axis of rotation Direct occlusal loads along the long axis of the implants Do not overload the implants when occlusal forces are applied to the prosthesis Provide effective retention on the normal sideFor the head and neck surgeon: To create maxillectomy defects with retentive qualities so as to counteract the forces of gravity and provide retention and stability on the defect side.
• 68. Solitary implants in the tuberosityl “0” ring attachments were used in the tuberosity site enabling the prosthesis to rotate in just about any plane.Result: Nonaxial forces delivered to theimplant are minimized.
• 69. Subsequent animal and humanstudies have reaffirmed ourconviction that the bone lossoccurring around the implants in ourearly cases was secondary to implantoverload leading to a resorptiveremodeling response of the bonearound the implants.
• 70. Implant Biomechanicsl Is there such a phenomenon as implant overload? If so, how does the bone surrounding the implant respond?Yes there is such a phenomenon. We now haveevidence from both clinical and animal studiesthat there is such a phenomenon and we arebeginning to understand the biologicmechanisms involved tissue response.
• 71. Bone Remodeling and the Possible Relation to Overloadl Hoshaw et al (1994) observed a resorptive remodeling of the bone around implants subjected to excessive axial loads (300N). Bone loss was observed at the crest around the neck of the implant and in the zone of bone adjacent to the body of the implant.l Isadors studies (1996, 1997) in monkeys presented data that was consistent with the hypothesis proposed by Hoshaw and her colleagues.
• 72. Implant Overload and Bone Resorption Mechanisms of Implant Failure*l Excessive occlusal loadsl Resulting microdamage (fractures, cracks, and delaminations)l Resorption remodeling response of bonel Increased porosity of bone in the interface zone secondary to remodelingl Vicious cycle of continued loading, more *Brunski et al, 2000) microdamage, more porosity until failure
• 73. Our challenge was to: Eliminate Implant Overload in Edentulous Maxillectomy PatientsMethods• Develop implant assisted tissue bar designs specifically tailored for maxillectomy defects• Provide better bone anchorage for osseointegrated implants in the maxilla
• 74. Eliminating Implant Overload in Edentulous Maxillectomy Patients Implant tissue bar designs should beimplant assisted. They should be designed to facilitate retention and stability. Theyshould not be the sole means of support. Ifocclusal forces are delivered, they should bydirected along the long axis of the implants.
• 75. Implant retained prostheses for maxillary defectsImplants are most predictable when the occlusal loads are directed alongthe long axis of the implants (A). Load magnification occurs when loads areapplied at an angle to the long axis (B). Load magnification can lead toimplant overload and resorptive remodeling response of the investing bone. A B Initial challenge: Design a tissue bar that directed occlusal loads axially.
• 76. Challenge in Edentulous Maxillectomy Defects: For the maxillofacial prosthodontist: l Develop tissue bar designs for radical maxillectomy defects that: Account for the multiple axis of rotation Direct occlusal loads along the long axis of the implants Do not overload the implants when occlusal forces are applied to the prosthesis Provide effective retention on the normal side For the surgeon: To create maxillectomy defects with retentive qualities so as to counteract the forces of gravity and provide retention on the defect side.
• 77. Photoelastic Analysisl Purpose: To identify implant assisted tissue bar designs for use in maxillectomy defects which provide adequate retention and best direct occlusal forces along the long axis of the implants.
• 78. Photoelastic analysis*l Several designs were tested including: Hader bar Bar with ERA attachments with and without rests Bar with “0” ring attachments *Davis B, et al,1995
• 79. Photoelastic analysis Tissue bars for maxillectomy defects Results “0” Ring bar design Hader bar designThe “0” ring type attachment resulted in the most favorablestress distribution and the Hader bar type resulted in the leastfavorable stress distribution.
• 80. Photoelastic analysis – Resultsl Best combination of retention and stress distribution was associated with the tissue bar with ERA type resilient attachments on either side with occlusal rests atop the bar.
• 81. Maxillectomy defects: Tissue bar designl ERA attachments are attached to each side and occlusal rests placed on top of the bar. The rests control the axes of rotation and allow the ERA attachments to function vertically.
• 82. Maxillectomy Defects – Tissue Bar DesignsThe metal suprastructure only engages thebar via the rests and the ERA attachments.This design minimizes the lateral torquingforces delivered to the implants and reducesthe risk of implant overload.
• 83. Maxillectomy Defects – Tissue Bar Designs Since we began using this design in the mid 1990’s bone loss around the implants has been almost totally eliminated.
• 84. Potential Implant Sitesl Residual premaxillary segmentl Residual posterior alveolar ridge Sinus lift and graftl Maxillary tuberosityl Zygoma Normal side Defect side
• 85. Implants in the Premaxilla l Best site in terms of quantity and quality l Limited number of implant sites remaining in the residual premaxillaEven when room for three exists Often there is room for onlythere is little A-P spread two implants
• 86. Premaxillary segmentl Best bone sites although some may have horizontal deficienciesl Principal problem: Limited anterior – posterior spreadl Retention bar designs must be implant assisted Rentention bars with ERA attachments and occlusal rests are the preferred design
• 87. Maxillary tuberosityl Poor quality bone – Fifty per cent of the implants placed fail to osseointegrate with the original machined surface implantsl This site used only when no others are availablel “0” Ring attachments are favored because they permit multiple axis of rotation
• 88. Posterior alveolar ridgeProblems Limited bone in most patients because of pneumatized sinuses. Few patients present with sufficient bone over the sinus. In this patient implants 10 mm in length were placed.
• 89. Zygoma Implants in the zygoma on theresected side are not recommended l Difficult hygiene access l Forces not applied along long axis l High probability of implant failure l A retentive skin lined defect provides just as much retention if magnetic attachments are used
• 90. Implants in the zygoma l The resected side – Problems The implants are located high in the defect, Delivery oral hygiene6difficult making months post delivery Implants are parallel to the plane of occlusion Consequently, only magnetic attachments can be used. The gains in retention with this type of attachment system are not significantDifficult hygiene access lead to accumulation of plague. Result: Peri-implantitis, tissue hypertrophy, bone loss and eventually loss of the implants
• 91. Immediate placement upon tumor resection l Useful in edentulous patients l Reserved for patients with localized tumors
• 92. Immediate placement upon tumor resectionNot indicated: l In patients scheduled to receive postoperative radiation therapy because of the dose enhancement effect at the bone implant interface
• 93. Case reportsl Patient is status post total palatectomy for an adenoidcystic carcinoma. Three implants were placed in the maxillary tuberosityl Note the excellent skin lined undercut in the left lateral wall of the defect
• 94. Case reports l This retention bar design used. The anterior Hader bar attachment (oval) was oriented parallel to the estimated access of rotation. The posterior Hader segment (arrow) was designed to facilitate stability.The anteriorimplant failed tointegrate andwas removed.
• 95. Case reportsl The finished obturator prosthesis The posterior Hader clip was made to be nonretentive Note the nasal aperture extensionTwo and one half years after delivery, the anterior implant failed. Failure waspreceded by steady, progressive bone loss. This loss was probably caused bythe long lever arm of the prosthesis leading to implant overload.
• 96. Case report l An “0” ring was secured to the remaining implant and the implant is still present eight years later with no significant bone loss. Why? The “0” ring permits rotation around just about any axis, whereas the previous design permitted rotation around just one axis. Result: The magnitude of lateral torquing forces delivered to the implant is minimized with the “0” ring attachment.
• 97. Total palatectomy restored using implants Speech and swallowing can be restored with an obturator. The single implant, combined with the nasal aperture extension and the extension up the lateral wall of the defect provided sufficient retention and stability.
• 98. Case reportl Patient is status post partial palatectomy. In addition, about two thirds of the soft palate had been removed. The defect was not lined with skin and provided no retentive undercuts. Note the torus tubaris (arrow). A lateral cephalometric x-ray indicated sufficient bone for placement of several implants in Denture adhesive was used the premaxilla. Only to retain the complete four of the six were denture and obturator uncovered.
• 99. Case report l Four implants of the six were uncovered and a bar fabricated. The maxillary molar was retained and used for posterior support. Note that most of the palatal shelf has been retained.An impression tray with retentiveclips is fabricated in preparation foran altered cast impression.
• 100. Case report l The retention provided by the bar enables the making of accurate altered cast impressions. The velopharyngeal area was border molded with dental compound and corrected with a thermoplastic wax.
• 101. Case reportl The completed altered cast impression and the master cast
• 102. Case report l Face bow and centric records were made and transferred to the articulator is the usual fashion. Bilateral balanced occlusion was employed. The completed prosthesis in position. It made a dramatic impact on the patient’s psychologic outlook. Retention was excellent and speech, mastication, and swallowing were completely restored.The completed completedenture and obturator
• 103. Case reportl Patient is status post maxillectomy. Note that the entire premaxilla has been removed. The defect is lined with skin and there is a nice undercut up the lateral wall of the defect. Fortunately, there was 8-10 mm of bone over the sinus and 4 implants were surgically inserted.
• 104. Case report l The right mandible was also resected. The soft tissue defect was restored with a radial forearm flap and mandibular continuity was maintained with a titanium reconstructive platePatient received 6000 cGy to the remaining mandibularbody. At a later date two osteointegrated implants wereplaced. However, one implant failed to osseointegrate.
• 105. Case report Maxillary complete denture and l Retention bar secured.obturator . Note the extension ontothe nasal side of the soft palate tofacilitate retention on the defect side. Completed denture in position. Note the lip plumper.
• 106. Implants in edentulous maxillectomy patients Patients Number of implants Success Treated placed uncovered buried failed %Irradiated 13 50 29 3 10 55.2Non-Irradiated 10 35 25 3 2 80.0Totals 23 85 54 6 12 66.7 Failures in the irradiated group tend to be late, after the implants have been loaded.
• 107. Proceed to: 9. Selected references and information about other programsoffered by the International Society of Maxillofacial Rehabilitation
• 108. Case ReportThis patient is S/P maxillectomy. The soft palate hasalso been resected. The anterior teeth were lostsecondary to periodontal bone loss. Implants wereplaced in the residual premaxillary segment.
• 109. Case ReportThe tissue bar is tried in to ensure it fits passively. Rests(arrows) are then positioned on the bar between theimplants. Occlusal forces are directed through the restsand ensures that most forces are directed along the longaxis of the implants.
• 110. Case Reportl Note the metal framework incorporated within the finished prosthesis. It contains the ERA attachments and the occlusal rests.
• 111. Case Reportl Note the contours of the obturator. The extension into the velopharyngeal area is about 10 mm in height.l Note the prominent gingival roll posteriorly on the defect side to deflect the cheek away from the biting surfaces The prosthesis in position. Note the elevation of the right lateral incisor and cuspid so as to follow the lip line.
• 112. Case Report
• 113. Case Report
• 114. Thank youl References: l Severo CB, Guazzeli LS, Severo LC. Chapter 7: Zygomycosis. J Bras Pneumol. Feb 2010, 36(1): 134-41. l Brown J. Zygomycosis: an emerging fungal infection. Am J Health Syst Pharm. Dec 2005, 62(24): 2593-6. l Sapp JP, Eversole LR, Wysocki GP. Chapter 7: Oral Infections. Contemp Oral Maxillof Path. 2nd edtn. 2004. 249. l Rogers TR. Treatment of Zygomycosis: current and new options. J. Antimicrob. Chemother. 2008. 61(1): i35-i40.