obturators / academy of fixed orthodontics
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www.indiandentalacademy.comwww.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com Maxillofacial prostheticsMaxillofacial prosthetics is the art andis the art and science of anatomic, functional, orscience of anatomic, functional, or cosmetic reconstruction by means of noncosmetic reconstruction by means of non living substitutes of those regions in theliving substitutes of those regions in the maxilla, mandible, and face that aremaxilla, mandible, and face that are missing or defective because of surgicalmissing or defective because of surgical intervention, trauma, pathology, orintervention, trauma, pathology, or developmental or congenital malformation.developmental or congenital malformation. www.indiandentalacademy.comwww.indiandentalacademy.com Objectives of Maxillofacial Prosthetics: The most importantThe most important objectivesobjectives of maxillofacialof maxillofacial prosthetics and rehabilitation include:prosthetics and rehabilitation include: 1.1. RRestoration of esthetics or cosmetic appearanceestoration of esthetics or cosmetic appearance of the patient.of the patient. 2.2. RRestoration of function.estoration of function. 3.3. PProtection of tissues.rotection of tissues. 4.4. TTherapeutic or healing effect.herapeutic or healing effect. 5.5. PPsychologic therapy.sychologic therapy. www.indiandentalacademy.comwww.indiandentalacademy.com Types of Maxillofacial Deformities CONGENITALCONGENITAL Cleft palateCleft palate Cleft lipCleft lip Facial cleftFacial cleft Missing earMissing ear PrognathismPrognathism ACQUIREDACQUIRED AccidentsAccidents SurgerySurgery PathologyPathology DEVELOPMENTALDEVELOPMENTAL PrognathismPrognathism RetrognathismRetrognathism www.indiandentalacademy.comwww.indiandentalacademy.com Probably the most common of allProbably the most common of all intraoralintraoral defects are in thedefects are in the maxillamaxilla, in the form of an, in the form of an openingopening into theinto the nasopharynxnasopharynx. The. The prosthesis needed to repair the defect isprosthesis needed to repair the defect is termed atermed a maxillary obturatormaxillary obturator.. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com Obturators AnAn obturatorobturator ((LatinLatin:: obturareobturare,, to stop upto stop up) is a disc) is a disc or plate, natural or artificial, which closes anor plate, natural or artificial, which closes an opening.opening. A prosthesis used to close a congenital orA prosthesis used to close a congenital or acquired tissue opening, primarily of the hardacquired tissue opening, primarily of the hard palate and/or contiguous structures.-palate and/or contiguous structures.-GPT-8GPT-8 www.indiandentalacademy.comwww.indiandentalacademy.com DEFINITIVE OBTURATOR A prothesis that artificially replaces part or all of the maxilla and associated teeth lost due to surgery or trauma. INTERIM OBTURATOR A prosthesis that is made several weeks or months following the surgical resection of a portion of one or both maxillae. It frequently includes replacement of teeth in the defect area. SURGICAL OBTURATOR A temporary prosthesis used to restore the continuity of the hard palate immediately after surgery or traumatic loss of a portion or all of the hard palate and/or contiguous alveolar structures (gingival tissue, teeth) www.indiandentalacademy.comwww.indiandentalacademy.com The obturator fulfills manyThe obturator fulfills many functionsfunctions.. 1.1. It can serve in lieu of a Levin tube for feeding purposes.It can serve in lieu of a Levin tube for feeding purposes. 2.2. It can be used to keep the wound or defective area cleanIt can be used to keep the wound or defective area clean 3.3. It can enhance the healing of traumatic or postsurgicalIt can enhance the healing of traumatic or postsurgical defects.defects. 4.4. It can help to reshape and reconstruct the palatal contourIt can help to reshape and reconstruct the palatal contour and/or soft palate.and/or soft palate. 5.5. It also improves speech or, in some instances, makesIt also improves speech or, in some instances, makes speech possible.speech possible. www.indiandentalacademy.comwww.indiandentalacademy.com 6.6. In the important area of esthetics, the obturator can beIn the important area of esthetics, the obturator can be used to correct lip and cheek position.used to correct lip and cheek position. 7.7. It can benefit the morale of patients with maxillaryIt can benefit the morale of patients with maxillary defects.defects. 8.8. When deglutition and mastication are impaired, it canWhen deglutition and mastication are impaired, it can be used to improve function.be used to improve function. 9.9. It reduces the flow of exudates into the mouth.It reduces the flow of exudates into the mouth. 10.10. The obturator can be used a a stent to hold dressingsThe obturator can be used a a stent to hold dressings or packs postsurgically in maxillary resections.or packs postsurgically in maxillary resections. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com TheThe Aramany classificationAramany classification system ofsystem of postsurgical maxillectomy defectspostsurgical maxillectomy defects is ais a useful tool for teaching and developinguseful tool for teaching and developing obturatorobturator framework designsframework designs andand enhancing communication amongenhancing communication among prosthodontists.prosthodontists. www.indiandentalacademy.comwww.indiandentalacademy.com This article describes a series of Aramany-This article describes a series of Aramany- obturatorobturator design templatesdesign templates and discussesand discusses the relevant considerations for each. In allthe relevant considerations for each. In all situations, asituations, a quadrilateral or tripodalquadrilateral or tripodal designdesign is favored over ais favored over a linear designlinear design because this allows a more favorablebecause this allows a more favorable leverage design application that will aid inleverage design application that will aid in thethe supportsupport,, stabilizationstabilization, and, and retentionretention ofof the prosthesis.the prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com IInn 19781978 the latethe late Dr.Mohammed AramanyDr.Mohammed Aramany presented the first published system ofpresented the first published system of classificationclassification ofof postsurgical maxillarypostsurgical maxillary defectsdefects.. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com He divided all defects intoHe divided all defects into 6 categories6 categories based on thebased on the relationship of the defect torelationship of the defect to the remaining teeth and the frequency ofthe remaining teeth and the frequency of occurrence of the defectoccurrence of the defect.. www.indiandentalacademy.comwww.indiandentalacademy.com Dr Aramany recognized that, in addition toDr Aramany recognized that, in addition to being communication tool, a classificationbeing communication tool, a classification that grouped particular combinations ofthat grouped particular combinations of teeth and surgical defects hadteeth and surgical defects had relevancerelevance to the eventual design of a maxillaryto the eventual design of a maxillary obturator prosthesis framework.obturator prosthesis framework. www.indiandentalacademy.comwww.indiandentalacademy.com The classification could be used to developThe classification could be used to develop a series of basic obturator designsa series of basic obturator designs (templates) that have proven(templates) that have proven clinicallyclinically successfulsuccessful andand scientifically acceptable inscientifically acceptable in particular situationsparticular situations.. These templates could then be applied toThese templates could then be applied to other dental arches of similar classificationother dental arches of similar classification or logically modified when slightly differentor logically modified when slightly different situations presented.situations presented. www.indiandentalacademy.comwww.indiandentalacademy.com He also recognized that although theHe also recognized that although the framework designs varied greatly withframework designs varied greatly with each group, the designeach group, the design objectives wereobjectives were always the samealways the same.. www.indiandentalacademy.comwww.indiandentalacademy.com Design andDesign and leverageleverage were to he used towere to he used to allocate, distribute, neutralize, or controlallocate, distribute, neutralize, or control the anticipated functional forces so thatthe anticipated functional forces so that each supporting, stabilizing, or retainingeach supporting, stabilizing, or retaining element of the oral cavity could be usedelement of the oral cavity could be used withwith maximum effectivenessmaximum effectiveness without beingwithout being stressed beyond its physiologic limits.stressed beyond its physiologic limits. www.indiandentalacademy.comwww.indiandentalacademy.com Preservation of the remaining teethPreservation of the remaining teeth, which, which is critical for support, stabilization, andis critical for support, stabilization, and retention of the prosthesis, is aretention of the prosthesis, is a primaryprimary goalgoal in all classes.in all classes. www.indiandentalacademy.comwww.indiandentalacademy.com GENERAL COMMENTS The general principles of removable partialThe general principles of removable partial denture (RPD) design apply to obturatordenture (RPD) design apply to obturator prosthesis design as well.prosthesis design as well. RelevantRelevant among these are:among these are: (1) The need for a rigid(1) The need for a rigid major connectormajor connector (2)(2) Guide planesGuide planes and other components thatand other components that facilitate stability and bracingfacilitate stability and bracing www.indiandentalacademy.comwww.indiandentalacademy.com (3) A design that maximizes(3) A design that maximizes supportsupport (4) Rests that place supporting(4) Rests that place supporting forces along theforces along the long axislong axis of the abutment toothof the abutment tooth (5)(5) Direct retainersDirect retainers that are passive at rest andthat are passive at rest and provide adequate resistance to dislodgmentprovide adequate resistance to dislodgment without overloading the abutment teethwithout overloading the abutment teeth (6)(6) Control of the occlusal planeControl of the occlusal plane that opposes thethat opposes the defect, especially when it involves natural teeth.defect, especially when it involves natural teeth. www.indiandentalacademy.comwww.indiandentalacademy.com In addition,In addition, many unique considerationsmany unique considerations involvedinvolved in the design are provided by thein the design are provided by the nature of thenature of the problem and the treatment requiredproblem and the treatment required.. Among these are:Among these are: (1) The(1) The location and sizelocation and size of the defect, especiallyof the defect, especially as it relates to the remaining teethas it relates to the remaining teeth (2) The importance of the(2) The importance of the abutment toothabutment tooth adjacentadjacent to the defect, which is critical to the support andto the defect, which is critical to the support and retention of the obturator prosthesisretention of the obturator prosthesis www.indiandentalacademy.comwww.indiandentalacademy.com (3) The usefulness of the(3) The usefulness of the lateral scar bandlateral scar band,, which flexes to allow insertion of thewhich flexes to allow insertion of the prosthesis but tends to resist itsprosthesis but tends to resist its displacementdisplacement (4) The use of the(4) The use of the surveyorsurveyor to examine theto examine the defect for the purpose of locating anddefect for the purpose of locating and preserving useful undercuts or eliminatingpreserving useful undercuts or eliminating undesirable undercuts.undesirable undercuts. www.indiandentalacademy.comwww.indiandentalacademy.com Forces that are important in designing an obturator prosthesis framework have been discussed by Aramany. Briefly, these are: Vertical downward forces, because of gravity Vertical upward (occlusal) forces www.indiandentalacademy.comwww.indiandentalacademy.com Rotational forces (which are multidirectional around constantly changing fulcrum lines) Anteroposterior forces, because of occlusal prematurities. The bony margin of the surgical defect oftenThe bony margin of the surgical defect often becomes an important fulcrum when thebecomes an important fulcrum when the obturator is fully seated and loaded.obturator is fully seated and loaded. www.indiandentalacademy.comwww.indiandentalacademy.com TheThe prognosisprognosis of the obturator will improve withof the obturator will improve with (1) The(1) The sizesize (amount remaining after surgery) and(amount remaining after surgery) and curvature of the archcurvature of the arch (2) The(2) The qualityquality of the tissue covering the ridge andof the tissue covering the ridge and lining the defectlining the defect (3) An(3) An abutment alignmentabutment alignment that isthat is curvedcurved instead ofinstead of linearlinear (4) The(4) The availability of teethavailability of teeth on the defect side foron the defect side for support and retention.support and retention. www.indiandentalacademy.comwww.indiandentalacademy.com Many designs require full coverage of the remaining palate for maximum support. In all in stances, the gingival margins should be relieved when they are crossed by the major connector to avoid impingement during function. The uncovering of the gingival margins in such a design should be discouraged because it is not a replacement for good oral hygiene and is probably not necessary for tissue stimulation if good hygiene is practiced. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com The class 1 category represents theThe class 1 category represents the classicclassic maxillary resectionmaxillary resection defect where the harddefect where the hard palate, alveolar, ridge, and dentition arepalate, alveolar, ridge, and dentition are removed to the midline. This unilateralremoved to the midline. This unilateral defect is the onedefect is the one most commonlymost commonly seen inseen in the maxillofacial rehabilitative practice.the maxillofacial rehabilitative practice. www.indiandentalacademy.comwww.indiandentalacademy.com Aramany made several recommendationsAramany made several recommendations regarding the framework design for thisregarding the framework design for this class, proposing aclass, proposing a linear designlinear design if theif the remaining anterior teeth were notremaining anterior teeth were not to beto be used for support or retentionused for support or retention andand aa tripodal design if the anterior teeth weretripodal design if the anterior teeth were usedused.. www.indiandentalacademy.comwww.indiandentalacademy.com Support Support is provided and shared by the remaining natural teeth, the palate, and any structures in the defect that may be contacted for this purpose. The goal is to ensure that the functional load is distributed as equally as possible to each of these structures via a rigid major connector. www.indiandentalacademy.comwww.indiandentalacademy.com The natural teeth are aided in this actionThe natural teeth are aided in this action when the support regions of the palate andwhen the support regions of the palate and the defect are loaded to their maximum,the defect are loaded to their maximum, without physiologic over load.without physiologic over load. www.indiandentalacademy.comwww.indiandentalacademy.com AA broad square or ovoid palatal formbroad square or ovoid palatal form aidsaids providing a greater tissue-bearing surface toproviding a greater tissue-bearing surface to resist forces (such as may be supplied by anresist forces (such as may be supplied by an occlusal load) and a greater potential forocclusal load) and a greater potential for tripodization to improve leverage.tripodization to improve leverage. AA tapering archtapering arch is less of an aid.is less of an aid. www.indiandentalacademy.comwww.indiandentalacademy.com Rests are placed on the most anterior abutmentRests are placed on the most anterior abutment (closest to the defect) and the mesio-occlusal(closest to the defect) and the mesio-occlusal surface of the most distal abutment tooth whensurface of the most distal abutment tooth when alignment & occlusion will permit. The mesio-alignment & occlusion will permit. The mesio- occlusal posterior rest, most often locatedocclusal posterior rest, most often located between adjacent posterior teeth, isbetween adjacent posterior teeth, is accompanied by a rest on the disto-occlusalaccompanied by a rest on the disto-occlusal surface of the more anterior adjacent tooth.surface of the more anterior adjacent tooth. www.indiandentalacademy.comwww.indiandentalacademy.com This addition rest willThis addition rest will prevent wedgingprevent wedging andand separation of two adjacent teeth and willseparation of two adjacent teeth and will decrease the possibility of periodontal damagedecrease the possibility of periodontal damage from food impaction.from food impaction. www.indiandentalacademy.comwww.indiandentalacademy.com The completed obturator often requires aThe completed obturator often requires a compound path of insertion as undercutscompound path of insertion as undercuts and support within the defect will beand support within the defect will be negotiated before the teeth are engaged.negotiated before the teeth are engaged. Guide planesGuide planes will assist in the precisewill assist in the precise placement of the prosthesis once the teethplacement of the prosthesis once the teeth have been contactedhave been contacted www.indiandentalacademy.comwww.indiandentalacademy.com They will alsoThey will also ensureensure more predictablemore predictable retention and add a greater degree ofretention and add a greater degree of stability to the prosthesis. Guide planes onstability to the prosthesis. Guide planes on the anterior abutment should be kept to athe anterior abutment should be kept to a minimum vertical height (1 to 2mm) to limitminimum vertical height (1 to 2mm) to limit torque on the abutment teeth and shouldtorque on the abutment teeth and should be physiologically adjusted.be physiologically adjusted. www.indiandentalacademy.comwww.indiandentalacademy.com This isThis is importantimportant since movement can besince movement can be expected during function because of theexpected during function because of the extensive lever arm provided by the defectextensive lever arm provided by the defect and the dual nature of the support system.and the dual nature of the support system. This consideration becomes more importantThis consideration becomes more important as the curvature of arch decreases and theas the curvature of arch decreases and the potential mechanical advantage of thepotential mechanical advantage of the indirect retainer is decreased.indirect retainer is decreased. www.indiandentalacademy.comwww.indiandentalacademy.com In this instant, it is especially important to use the palatal surfaces posterior teeth for additional bracing and stability www.indiandentalacademy.comwww.indiandentalacademy.com An indirect retainer is usually located perpendicular to the fulcrum line (which connects the most anterior and most posterior rests) & as forward as possible. This is usually a canine or first premolar. www.indiandentalacademy.comwww.indiandentalacademy.com Strategically placed indirect retainers allowStrategically placed indirect retainers allow maximum use of leverage to resist movement of themaximum use of leverage to resist movement of the prosthesis in a downward direction by the pull ofprosthesis in a downward direction by the pull of gravity acting on the defect side.gravity acting on the defect side. www.indiandentalacademy.comwww.indiandentalacademy.com RetentionRetention Retention is supplied by direct retainerRetention is supplied by direct retainer designs that allow maximum protection ofdesigns that allow maximum protection of the abutment teeth during functionalthe abutment teeth during functional movements. On the anterior abutment, amovements. On the anterior abutment, a 19- or 20-gauge wrought wire clasp of the19- or 20-gauge wrought wire clasp of the I-bar design is often used to engage aI-bar design is often used to engage a 0.25-mm undercut on the midlabial surface0.25-mm undercut on the midlabial surface of this abutment.of this abutment. www.indiandentalacademy.comwww.indiandentalacademy.com Additional protection is afforded to thisAdditional protection is afforded to this tooth by splinting it to 1 or 2 adjacent teethtooth by splinting it to 1 or 2 adjacent teeth with full crowns when possible or acid-with full crowns when possible or acid- etch composite resin techniques whenetch composite resin techniques when crowns are not possible.crowns are not possible. www.indiandentalacademy.comwww.indiandentalacademy.com Other possibilities include a variety ofOther possibilities include a variety of castcast clasp assembliesclasp assemblies located on the height oflocated on the height of contour for frictional retention only.contour for frictional retention only. www.indiandentalacademy.comwww.indiandentalacademy.com The posterior retainer is most often a castThe posterior retainer is most often a cast circumferential clasp using 0.25 mmcircumferential clasp using 0.25 mm undercut on the buccal surface. Theundercut on the buccal surface. The placement of posterior clasps facing inplacement of posterior clasps facing in both an anterior and posterior direction willboth an anterior and posterior direction will aid in retaining both the anterior andaid in retaining both the anterior and posterior portions of the prosthesis.posterior portions of the prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com The linear design is used for the class IThe linear design is used for the class I defect when there are no anterior teethdefect when there are no anterior teeth present or when one does not desire topresent or when one does not desire to use the anterior teeth. The remaininguse the anterior teeth. The remaining posterior teeth are usually in aposterior teeth are usually in a relativelyrelatively straight line.straight line. www.indiandentalacademy.comwww.indiandentalacademy.com Support In the linear design, support is provided by the remaining posterior teeth and the palatal tissues. The palate becomes more important in the linear design because the use of leverage to resist vertical dislodging forces is decreased. www.indiandentalacademy.comwww.indiandentalacademy.com RetentionRetention Retention is usually provided by theRetention is usually provided by the combined use of buccal premolarcombined use of buccal premolar retention and lingual molar retention.retention and lingual molar retention. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com Class II includes arches in which theClass II includes arches in which the premaxilla and the premaxillarv dentitionpremaxilla and the premaxillarv dentition on the contralateral side is maintained. Aon the contralateral side is maintained. A single, unilateral defect is located posteriorsingle, unilateral defect is located posterior to the remaining teeth.to the remaining teeth. www.indiandentalacademy.comwww.indiandentalacademy.com This arch isThis arch is similar to a Kennedy class IIsimilar to a Kennedy class II in that a bilateral, tripodal design canin that a bilateral, tripodal design can always be used. Presurgical consultationalways be used. Presurgical consultation with the surgeon is an important aspect ofwith the surgeon is an important aspect of care.care. www.indiandentalacademy.comwww.indiandentalacademy.com Surgeons should be informed of theSurgeons should be informed of the improved prosthetic prognosis when aimproved prosthetic prognosis when a class I situation can be converted to aclass I situation can be converted to a class II situation by carefully plannedclass II situation by carefully planned surgery, assuming that tumor removal issurgery, assuming that tumor removal is not compromised.not compromised. www.indiandentalacademy.comwww.indiandentalacademy.com SupportSupport Support is similar to that in class I and isSupport is similar to that in class I and is provided by rests (located on the abutmentprovided by rests (located on the abutment nearest to the defect and farthest from thenearest to the defect and farthest from the defect) as well as the palate.defect) as well as the palate. Support and stability are maximized bySupport and stability are maximized by generating the largest tripodal design possiblegenerating the largest tripodal design possible and again will be aided by aand again will be aided by a square or ovoidsquare or ovoid palatal formpalatal form.. Double restsDouble rests are used betweenare used between adjacent posterior teeth.adjacent posterior teeth. www.indiandentalacademy.comwww.indiandentalacademy.com Guide-plane locationGuide-plane location and size is similar toand size is similar to the class I situation with full use of thethe class I situation with full use of the palatal surfaces of the posterior teeth.palatal surfaces of the posterior teeth. AnAn indirect retainerindirect retainer located opposite thelocated opposite the fulcrum line and as forward as possiblefulcrum line and as forward as possible usually is located on theusually is located on the canine or firstcanine or first premolarpremolar and completes the tripodal design.and completes the tripodal design. www.indiandentalacademy.comwww.indiandentalacademy.com RetentionRetention Retention is provided in a fashion similar toRetention is provided in a fashion similar to that in the class I design. Thethat in the class I design. The abutmentabutment tooth locatedtooth located closestclosest to the defect isto the defect is criticalcritical for retentionfor retention and should be engaged with aand should be engaged with a direct retainer design that resists downwarddirect retainer design that resists downward displacement but tends to rotate, disengage,displacement but tends to rotate, disengage, or flex when upward forces are applied.or flex when upward forces are applied. www.indiandentalacademy.comwww.indiandentalacademy.com A cast circumferential clasp or an I-bar claspA cast circumferential clasp or an I-bar clasp is frequently used in a 0.25 mm undercutis frequently used in a 0.25 mm undercut when the retentive terminus can be locatedwhen the retentive terminus can be located on the fulcrum line. A 19-gauge wrought wireon the fulcrum line. A 19-gauge wrought wire clasp in a 0.5 mm or less mesiofacialclasp in a 0.5 mm or less mesiofacial undercut is also a frequent choice.undercut is also a frequent choice. Additional protection can be provided for thisAdditional protection can be provided for this tooth by splinting it to the one or two teethtooth by splinting it to the one or two teeth adjacent to it.adjacent to it. www.indiandentalacademy.comwww.indiandentalacademy.com TheThe posterior retainerposterior retainer is most frequently ais most frequently a cast circumferential claspcast circumferential clasp using a 0.25-using a 0.25- mm distobuccal undercut. The placementmm distobuccal undercut. The placement of posterior clasp assemblies facing inof posterior clasp assemblies facing in both an anterior and posterior direction willboth an anterior and posterior direction will aid in retaining both the anterior andaid in retaining both the anterior and posterior portions of the prosthesis.posterior portions of the prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com The anterior facing clasp will also serve toThe anterior facing clasp will also serve to aid any additional clasps placed oppositeaid any additional clasps placed opposite the fulcrum line from the defect. Thethe fulcrum line from the defect. The caninecanine is frequently the location of theis frequently the location of the indirect retainer and also serves as anindirect retainer and also serves as an additional (but optional) retentive site,additional (but optional) retentive site, engaged with a 19-gauge wrought wireengaged with a 19-gauge wrought wire clasp in a 0.25-mm undercut.clasp in a 0.25-mm undercut. www.indiandentalacademy.comwww.indiandentalacademy.com The canine is important in resistingThe canine is important in resisting occlusally directed forces and will receiveocclusally directed forces and will receive severe stress. If ansevere stress. If an additional claspadditional clasp isis required on the canine, it should be arequired on the canine, it should be a moremore flexibleflexible clasp in less than the normalclasp in less than the normal amount of undercut or a less flexible claspamount of undercut or a less flexible clasp on the height of contour so thaton the height of contour so that frictionalfrictional retention will be supplied.retention will be supplied. www.indiandentalacademy.comwww.indiandentalacademy.com A combination of buccal and palatal retention isA combination of buccal and palatal retention is almost never indicated for this classification foralmost never indicated for this classification for several reasons.several reasons. Among these are :Among these are : (1)(1) Additional bracingAdditional bracing andand cross-arch stabilizationcross-arch stabilization willwill bebe lostlost when lingual retention is engaged.when lingual retention is engaged. (2)(2) Increased rotation will be notedIncreased rotation will be noted with an actualwith an actual decrease in retention because to the short lengthdecrease in retention because to the short length and shallow gingivally located curvature of theand shallow gingivally located curvature of the palatal surfaces of the molar teeth andpalatal surfaces of the molar teeth and disengagement of the lingual undercut on slightdisengagement of the lingual undercut on slight displacement; anddisplacement; and www.indiandentalacademy.comwww.indiandentalacademy.com 3) The location of lingual retentive clasps often results in a major connector that has multiple small regions that trap food or irritate the tongue. Occlusion on the defect side is important because the occlusally directed forces can be destructive. Occlusal schemes with fewer, smaller teeth, located further toward the anterior and devoid of premature or deflective contacts is desirable. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com Class III involves a midline defect of the hardClass III involves a midline defect of the hard palate and may include a variable portion ofpalate and may include a variable portion of the soft palate as well. The dentition is usuallythe soft palate as well. The dentition is usually preserved, making this obturator prosthesispreserved, making this obturator prosthesis design simple and effective. The classificationdesign simple and effective. The classification and design closely resemble theand design closely resemble the KennedyKennedy class III RPD design.class III RPD design. www.indiandentalacademy.comwww.indiandentalacademy.com SupportSupport Support is supplied by the remainingSupport is supplied by the remaining natural teethnatural teeth viavia widely separated andwidely separated and bilaterally located restsbilaterally located rests. The canines and. The canines and molars are usually selected to generatemolars are usually selected to generate the largest quadrilateral shape possiblethe largest quadrilateral shape possible while avoiding alignment and occlusionwhile avoiding alignment and occlusion and hygiene problems, and providingand hygiene problems, and providing good esthetics.good esthetics. www.indiandentalacademy.comwww.indiandentalacademy.com Little or no support is expected from theLittle or no support is expected from the palate or the defect. Bilateral symmetry ofpalate or the defect. Bilateral symmetry of the major connector design and avoidance ofthe major connector design and avoidance of the rugae area is desirable when possible.the rugae area is desirable when possible. www.indiandentalacademy.comwww.indiandentalacademy.com Guide planes are usuallyGuide planes are usually shortshort because theybecause they are located on the palatal surfaces of theare located on the palatal surfaces of the posterior teeth. The proximal surfaces mayposterior teeth. The proximal surfaces may be liberally used if edentulous spaces arebe liberally used if edentulous spaces are present. Very little movement of thepresent. Very little movement of the prosthesis should occur in function;prosthesis should occur in function; therefore, these guide planes may be longtherefore, these guide planes may be long and physiologic adjustment should not beand physiologic adjustment should not be necessary.necessary. www.indiandentalacademy.comwww.indiandentalacademy.com Indirect retentionIndirect retention is not required becauseis not required because each terminus is supported by aeach terminus is supported by a directdirect retainerretainer; therefore, rotation around a; therefore, rotation around a common fulcrum should not occur.common fulcrum should not occur. www.indiandentalacademy.comwww.indiandentalacademy.com RetentionRetention Retention is often provided withRetention is often provided with castcast retainersretainers usingusing 0.25-mm undercuts0.25-mm undercuts on theon the facial surfaces of the teeth. These may befacial surfaces of the teeth. These may be circumferential retainerscircumferential retainers,, I-barsI-bars, or, or modified T-barsmodified T-bars, depending on the location, depending on the location of the retentive sites, the estheticof the retentive sites, the esthetic requirements, and the presence of tissuerequirements, and the presence of tissue undercuts.undercuts. www.indiandentalacademy.comwww.indiandentalacademy.com Combination-type retainers can be used toCombination-type retainers can be used to an esthetic advantage because they canan esthetic advantage because they can engage a deeper undercutengage a deeper undercut (0.5 mm) and(0.5 mm) and may thus be placed in amay thus be placed in a less conspicuousless conspicuous regionregion.. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com Aramany class IV obturator is a linear design because of presence of only posteriorAramany class IV obturator is a linear design because of presence of only posterior teeth in a straight line. Retention is problematic. Combination of buccal and lingualteeth in a straight line. Retention is problematic. Combination of buccal and lingual retention may be necessary if useful retention cannot be found within defect.retention may be necessary if useful retention cannot be found within defect. www.indiandentalacademy.comwww.indiandentalacademy.com Class IV situationsClass IV situations involveinvolve the surgicalthe surgical removal of the entire premaxillae, leavingremoval of the entire premaxillae, leaving aa bilateral defect anteriorlybilateral defect anteriorly andand a laterala lateral defect posteriorlydefect posteriorly. There are often a few. There are often a few remaining posterior teeth located in aremaining posterior teeth located in a relatively straight line, creating a unilateralrelatively straight line, creating a unilateral linear design problem where leveragelinear design problem where leverage cannot be used to an effective degree.cannot be used to an effective degree. www.indiandentalacademy.comwww.indiandentalacademy.com SupportSupport Support is usually provided bySupport is usually provided by restsrests locatedlocated centrally on all of the remaining teeth.centrally on all of the remaining teeth. Channel rests or multiple mesio-occlusalChannel rests or multiple mesio-occlusal and disto-occlusal results are oftenand disto-occlusal results are often designed. Thedesigned. The defectdefect should also beshould also be engaged to use, as much as possible, anyengaged to use, as much as possible, any sites within the defect that may besites within the defect that may be contacted.contacted. www.indiandentalacademy.comwww.indiandentalacademy.com These are the midline of the palatal incision,These are the midline of the palatal incision, when palatal mucosa has been preserved towhen palatal mucosa has been preserved to cover this region, the floor of the orbit, thecover this region, the floor of the orbit, the bony pterygoid plates, and the anteriorbony pterygoid plates, and the anterior surface of the temporal bone. If these regionssurface of the temporal bone. If these regions are covered by respiratory mucosa from theare covered by respiratory mucosa from the nasal cavity, little added support can benasal cavity, little added support can be achieved.achieved. www.indiandentalacademy.comwww.indiandentalacademy.com RetentionRetention Retention in this classification isRetention in this classification is problematicproblematic. Often a mixture of. Often a mixture of buccalbuccal retentionretention on the premolars andon the premolars and palatalpalatal retentionretention on the molars is used in a fashionon the molars is used in a fashion similar to the class I linear design.similar to the class I linear design. www.indiandentalacademy.comwww.indiandentalacademy.com This leads often to the same problemsThis leads often to the same problems discussed indiscussed in class IIclass II situations when asituations when a combination of buccal and palatalcombination of buccal and palatal retention is used:retention is used: loss of bracing aridloss of bracing arid stabilizationstabilization,, increased rotationincreased rotation, and, and thethe creation of small irritating spacescreation of small irritating spaces in thein the major connector design.major connector design. www.indiandentalacademy.comwww.indiandentalacademy.com Retentive sites should be located on theRetentive sites should be located on the facial surfaces of the remaining teeth andfacial surfaces of the remaining teeth and the lateral wall of the surgical defect viathe lateral wall of the surgical defect via thethe superiolateral extensionsuperiolateral extension of theof the obturator section in the engagement of theobturator section in the engagement of the lateral scar band.lateral scar band. Reduced posteriorReduced posterior occlusionocclusion (size and number of teeth) is(size and number of teeth) is also a useful suggestion.also a useful suggestion. www.indiandentalacademy.comwww.indiandentalacademy.com If noIf no lateral scar bandlateral scar band exists, because aexists, because a split-thickness skin graft was not placed orsplit-thickness skin graft was not placed or because one could not be maintained, thebecause one could not be maintained, the prosthodontist may haveprosthodontist may have no choiceno choice but tobut to use a combination of buccal and palataluse a combination of buccal and palatal retention.retention. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com This situation involves aThis situation involves a bilateral posteriorbilateral posterior surgical defectsurgical defect located posterior to thelocated posterior to the remaining teeth. Many or all of the teethremaining teeth. Many or all of the teeth are present anterior to the defect. Labialare present anterior to the defect. Labial stabilization and the use of splinting,stabilization and the use of splinting, especially of the terminal abutments, isespecially of the terminal abutments, is desirable.desirable. www.indiandentalacademy.comwww.indiandentalacademy.com SupportSupport Support is provided by rests located on theSupport is provided by rests located on the mesio-occlusalmesio-occlusal surface of the most posteriorsurface of the most posterior abutment. These rests define theabutment. These rests define the fulcrum linefulcrum line around which most of the expected movementaround which most of the expected movement will occur. If adjacent teeth are involved, doublewill occur. If adjacent teeth are involved, double rests are used for reasons outlined earlier.rests are used for reasons outlined earlier. StabilizationStabilization andand bracingbracing is provided by broadis provided by broad palatal coverage and contact with the palatalpalatal coverage and contact with the palatal surfaces of the remaining teeth.surfaces of the remaining teeth. www.indiandentalacademy.comwww.indiandentalacademy.com Indirect retention is provided by restsIndirect retention is provided by rests located as far forward of thelocated as far forward of the fulcrumfulcrum lineline as possible. This usually placesas possible. This usually places them on thethem on the central incisorscentral incisors, which, which often presents an occlusal problemoften presents an occlusal problem that may requirethat may require minor occlusalminor occlusal equilibrationequilibration.. www.indiandentalacademy.comwww.indiandentalacademy.com The location of the indirect retainer essentially converts the design to an efficient large tripod that uses leverage to resist downward displacement of the prosthesis. Positive rest seats are a critical necessity to eliminate the strong labial force generated by the downward movement of the prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com RetentionRetention The I-bar retainer is ideally suited for thisThe I-bar retainer is ideally suited for this situation. Located in asituation. Located in a 0.25-mm0.25-mm midbuccalmidbuccal undercut very close to theundercut very close to the fulcrum linefulcrum line, it, it provides for resistance to dislodgment andprovides for resistance to dislodgment and rotates in function. When the remaining softrotates in function. When the remaining soft palate is scarred and relatively immobile it canpalate is scarred and relatively immobile it can also be used to provide added retention fur thealso be used to provide added retention fur the posterior portion of the prosthesis.posterior portion of the prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com A swing-lock type of prosthesis is a designA swing-lock type of prosthesis is a design possibility in this situation, especially if thepossibility in this situation, especially if the patient can tolerate splinting of all of thepatient can tolerate splinting of all of the remaining teeth.remaining teeth. www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com The class VI defect is aThe class VI defect is a rare surgicalrare surgical creationcreation. Most of ten it results from a. Most of ten it results from a congenital anomaly or trauma such as ancongenital anomaly or trauma such as an automobile accidentautomobile accident or aor a self-inflictedself-inflicted woundwound that removes the entire premaxillaethat removes the entire premaxillae (and may include a portion of one or both of(and may include a portion of one or both of the maxillae), leaving a single bilateralthe maxillae), leaving a single bilateral defect located anterior to the remainingdefect located anterior to the remaining teeth.teeth. www.indiandentalacademy.comwww.indiandentalacademy.com Surgical defectsSurgical defects of this nature are usuallyof this nature are usually smallsmall.. NonsurgicalNonsurgical defects are usuallydefects are usually largelarge and difficult to manage.and difficult to manage. www.indiandentalacademy.comwww.indiandentalacademy.com SupportSupport Support is provided by rests located on theSupport is provided by rests located on the disto occlusal surfaces of the most anteriordisto occlusal surfaces of the most anterior abutment teeth. Double rests are usedabutment teeth. Double rests are used when adjacent posterior teeth are involved.when adjacent posterior teeth are involved. Greater stability is provided by placingGreater stability is provided by placing additional rests as far posteriorly asadditional rests as far posteriorly as possible.possible. www.indiandentalacademy.comwww.indiandentalacademy.com The most posterior rests, similar to theThe most posterior rests, similar to the Kennedy class IV situation, may beKennedy class IV situation, may be considered indirect retainers, resisting theconsidered indirect retainers, resisting the vertical downward displacement of thevertical downward displacement of the anterior segment of the prosthesis. Inanterior segment of the prosthesis. In extremely large class VI situations, indirectextremely large class VI situations, indirect retention may not be possible.retention may not be possible. www.indiandentalacademy.comwww.indiandentalacademy.com The remaining natural teeth provide all of theThe remaining natural teeth provide all of the support, with little support derived from the defect.support, with little support derived from the defect. Guide planes are usually located on theGuide planes are usually located on the proximal stir- faces adjacent to the defect andproximal stir- faces adjacent to the defect and should be kept to minimal lengthshould be kept to minimal length (1 to 2 mm)(1 to 2 mm) toto avoidavoid traumatrauma to the abutment teeth duringto the abutment teeth during expected movements of the prosthesis.expected movements of the prosthesis. Splinting with a cross-arch tissue bar is also aSplinting with a cross-arch tissue bar is also a possibility.possibility. www.indiandentalacademy.comwww.indiandentalacademy.com RetentionRetention Retention is most often provided simplyRetention is most often provided simply with cast retainers usingwith cast retainers using 0.25 mm0.25 mm of facialof facial undercut. The I-bar located on the anteriorundercut. The I-bar located on the anterior abutment in a midfacial undercut close toabutment in a midfacial undercut close to the fulcrum line can function effectively.the fulcrum line can function effectively. www.indiandentalacademy.comwww.indiandentalacademy.com Combination retainers may also be usedCombination retainers may also be used on the anterior abutments foron the anterior abutments for estheticesthetic reasons or when protection of the anteriorreasons or when protection of the anterior abutments is a consideration.abutments is a consideration. Effective accessory retention can also beEffective accessory retention can also be achieved by extending the prosthesisachieved by extending the prosthesis anteriorly into theanteriorly into the nasal aperturenasal aperture. Cosmetic. Cosmetic support of the nose and upper lip is alsosupport of the nose and upper lip is also possible when adequate retention is present.possible when adequate retention is present. www.indiandentalacademy.comwww.indiandentalacademy.com SUMMARY AND CONCLUSIONSUMMARY AND CONCLUSION The Aramany classification system ofThe Aramany classification system of postsurgical maxillary defects is a useful tool forpostsurgical maxillary defects is a useful tool for teaching and developing framework designs forteaching and developing framework designs for obturator prostheses and for enhancingobturator prostheses and for enhancing communication among prosthodontists.communication among prosthodontists. A series of obturator prosthesis designA series of obturator prosthesis design templates and the relevant considerations fortemplates and the relevant considerations for each has been discussed.each has been discussed. www.indiandentalacademy.comwww.indiandentalacademy.com In all situations, aIn all situations, a quadrilateralquadrilateral oror tripodaltripodal design is favored over a lineardesign is favored over a linear design because this allows a moredesign because this allows a more favorable application of leverage designfavorable application of leverage design for the support, stabilization, and retentionfor the support, stabilization, and retention of the prosthesis.of the prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com The templates provided should heThe templates provided should he considered basic types that can beconsidered basic types that can be applied in similar situations or logicallyapplied in similar situations or logically modified by using the design principlesmodified by using the design principles presented when the situation warrants.presented when the situation warrants. www.indiandentalacademy.comwww.indiandentalacademy.com Some of these situations may be medicalSome of these situations may be medical necessity, the presence of modificationnecessity, the presence of modification spaces, periodontal considerations,spaces, periodontal considerations, opposing occlusion, location of hard oropposing occlusion, location of hard or soft tissue undercuts, contingencysoft tissue undercuts, contingency planning, or the desire to simplify theplanning, or the desire to simplify the design.design. www.indiandentalacademy.comwww.indiandentalacademy.com Although some dentists may disagree withAlthough some dentists may disagree with the various facets of the templatesthe various facets of the templates presented, there is value for the student,presented, there is value for the student, teacher, or practitioner in the developmentteacher, or practitioner in the development of a systematic analysis of the design ofof a systematic analysis of the design of maxillary obturator prostheses.maxillary obturator prostheses. www.indiandentalacademy.comwww.indiandentalacademy.com REFERENCESREFERENCES 1.1. Aramany MA. Basic principles of obturatorAramany MA. Basic principles of obturator design for partially edentulous patients. Part I:design for partially edentulous patients. Part I: classification. J Prosthet Dent 1978;40: 554-7.classification. J Prosthet Dent 1978;40: 554-7. 2.2. Rahn AO, Goldman BC, Parr CR.Rahn AO, Goldman BC, Parr CR. Prosthodontic principles in the surgicalProsthodontic principles in the surgical planning for maxillary and mandibularplanning for maxillary and mandibular resection patients. J Prosthet Dentresection patients. J Prosthet Dent 1979;42:429-33.1979;42:429-33. 3.3. Brown KE. Peripheral considerations inBrown KE. Peripheral considerations in improving obturator retention. J Prosthet Dentimproving obturator retention. J Prosthet Dent 1968;20: 176-80.1968;20: 176-80. www.indiandentalacademy.comwww.indiandentalacademy.com 4. Beumer J, Curtis TA, .Firtell DN. maxillofacial4. Beumer J, Curtis TA, .Firtell DN. maxillofacial rehabilitation. St. Louis Mosby; 1979. p. 188-243.rehabilitation. St. Louis Mosby; 1979. p. 188-243. 5, Aramanv MA. Basic principles of obturator design5, Aramanv MA. Basic principles of obturator design for partially edentulous patients. Part II: designfor partially edentulous patients. Part II: design principles. J Prosthet Dent 1978;40:656-62.principles. J Prosthet Dent 1978;40:656-62. 6. Firtell DN, Grisius RI. Retention of obturator6. Firtell DN, Grisius RI. Retention of obturator removable partial dentures: a comparison ofremovable partial dentures: a comparison of buccal and lingual retention. J Prosthet Dentbuccal and lingual retention. J Prosthet Dent 1980;43:212-7.1980;43:212-7. www.indiandentalacademy.comwww.indiandentalacademy.com 7. Desjardins RP. Obturator prosthesis design for7. Desjardins RP. Obturator prosthesis design for acquired maxillary defects.acquired maxillary defects. J Prosthet DentJ Prosthet Dent 1978;39:424-32.1978;39:424-32. 8. Fiebiger GE, Rahn AO, Lundquist DO, Moise8. Fiebiger GE, Rahn AO, Lundquist DO, Moise PK.PK. Movement abutments by removable partialMovement abutments by removable partial denture frameworks with a hemimaxillectomydenture frameworks with a hemimaxillectomy obturator. J Prosthet Dent 1975,34:555-60.obturator. J Prosthet Dent 1975,34:555-60. 9. Stewart KL, Rudd KD, Kuebker WA. Clinical9. Stewart KL, Rudd KD, Kuebker WA. Clinical removable partial prosthodontics. St. Louis:removable partial prosthodontics. St. Louis: Mosby; 1983. p. 663.Mosby; 1983. p. 663. www.indiandentalacademy.comwww.indiandentalacademy.com For more details please visit www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com