Precision attachments in prosthodontics/ orthodontic seminars

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Precision attachments in prosthodontics/ orthodontic seminars

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
  2. 2. PRECISION ATTACHMENTS www.indiandentalacademy.comwww.indiandentalacademy.com
  3. 3. CONTENTS  Introduction  History  Definition and synonyms of attachments  Classification  Indications / Applications of precision attachments  Contraindication  Advantages  Disadvantages  Selection of the abutment teeth  Requirement of the abutment teeth  Selection of the retainer  Selection of the attachment www.indiandentalacademy.comwww.indiandentalacademy.com
  4. 4. www.indiandentalacademy.comwww.indiandentalacademy.com
  5. 5.  Intracoronal attachment • Precision / Semiprecision attachments • Mechanics of retention  Extracoronal attachment • Rigid / Resilient attachment • Extracoronal resilient attachment (ERA) • O-ring attachment  Role of attachment as stress breaker : “Broken stress philosophy”  Bar attachments  Stud attachments (DEB + overdenture attachments)  Magnets as attachment  Auxillary attachments  Conclusion www.indiandentalacademy.comwww.indiandentalacademy.com
  6. 6. www.indiandentalacademy.comwww.indiandentalacademy.com
  7. 7.  One of the purposes in theOne of the purposes in the “Healing Art”“Healing Art” is to preserve andis to preserve and maintain each bodily organ to its fullest extent. Themaintain each bodily organ to its fullest extent. The functions of teeth and mouth are as important in dailyfunctions of teeth and mouth are as important in daily exercises in human endeavor as that of any other part of theexercises in human endeavor as that of any other part of the body.body.  We live in a demanding society as standard ofWe live in a demanding society as standard of education, wealth and leisure rise, so do expectations. Oureducation, wealth and leisure rise, so do expectations. Our patients are beginning to apply these expectations aspatients are beginning to apply these expectations as forcibly to dentistry as to any other activity and increasingforcibly to dentistry as to any other activity and increasing their demand for the high standards of dental care that theirtheir demand for the high standards of dental care that their wealth can buy and the good appearance that society teacheswealth can buy and the good appearance that society teaches them to value.them to value. www.indiandentalacademy.comwww.indiandentalacademy.com
  8. 8.  In some situations, usually in the anterior segmentsIn some situations, usually in the anterior segments of the mouth the FPD cannot fulfill the cosmeticof the mouth the FPD cannot fulfill the cosmetic needs of a patient without imposing hygieneneeds of a patient without imposing hygiene problems, in that case RPD is most useful. But theproblems, in that case RPD is most useful. But the clasps on the anterior teeth are not cosmeticallyclasps on the anterior teeth are not cosmetically acceptable.acceptable.  The balance between the functional stability andThe balance between the functional stability and cosmetic appeal is a major challenge to the dentist.cosmetic appeal is a major challenge to the dentist. A variety of solutions have been proposed in theA variety of solutions have been proposed in the form of interlocking devices often called “Precisionform of interlocking devices often called “Precision Attachment” designed to connect the prosthesis toAttachment” designed to connect the prosthesis to the abutmentthe abutment www.indiandentalacademy.comwww.indiandentalacademy.com
  9. 9. GOALSGOALS  TheThe goalsgoals for fabrication of PA partial denture area asfor fabrication of PA partial denture area as follows:follows:  To provide an efficient masticating replacement ofTo provide an efficient masticating replacement of lost dental organs.lost dental organs.  To be removable and replaceable without stress orTo be removable and replaceable without stress or strain on the abutment teeth.strain on the abutment teeth.  To allow normal anatomic form to the abutment teeth.To allow normal anatomic form to the abutment teeth.  To be capable of being tissue supported in aTo be capable of being tissue supported in a controlled mannercontrolled manner www.indiandentalacademy.comwww.indiandentalacademy.com
  10. 10.  To allow for various occlusal correction andTo allow for various occlusal correction and provide many years of comfortable servicesprovide many years of comfortable services  To be esthetically acceptable and MinimalTo be esthetically acceptable and Minimal amount of tooth structure removed.amount of tooth structure removed.  To avoid endodontic procedures and to beTo avoid endodontic procedures and to be hygienically cleanhygienically clean  To place minimum amount of strain on theTo place minimum amount of strain on the abutment teethabutment teeth www.indiandentalacademy.comwww.indiandentalacademy.com
  11. 11. Late 19th century : Dr.Herman, ES Chayes First attachment to be available in the general market “T shaped” Precision Attachment (1906) “H shaped” Chayes Attachment (1912) www.indiandentalacademy.comwww.indiandentalacademy.com
  12. 12. Precision – quality or state of being precise Attachment – Mechanical device for the fixation, retention and stabilization of dental prosthesis. “A retainer consisting of a metal receptacle (matrix) and a closely fitting part (patrix) the matrix is usually contained within the normal or expanded contours of the crown on the abutment tooth/dental implant and the patrix is attached to a pontic or the removable dental prosthesis framework”. GPT-8 www.indiandentalacademy.comwww.indiandentalacademy.com
  13. 13. Mechanical device – Direct retainer • They are designed to replace occlusal rest, bracing arm, and retaining arm of the conventional clasp retained partial denture. • They function to retain, support and stabilize the removable partial denture. www.indiandentalacademy.comwww.indiandentalacademy.com
  14. 14. SYNONYMS OF ATTACHMENTS PatrixPatrix MatrixMatrix FlangeFlange SlotSlot InsertInsert CryptCrypt KeyKey KeywayKeyway Fitting partFitting part ReceptacleReceptacle Internal attachments Frictional attachments Parallel attachments Slotted attachments Key and Key way attachments.   Male attachments Female attachments www.indiandentalacademy.comwww.indiandentalacademy.com
  15. 15. CLASSIFICATION OF ATTACHMENTS Based on method of fabrication and the tolerance of fit I. Precision attachment (prefabricated types) II. Semiprecision attachment (custom made / laboratory made types) Prefabricated wax / plastic / nylon patternswww.indiandentalacademy.comwww.indiandentalacademy.com
  16. 16.  According to their relationship to the abutment teeth Intracoronal (Internal attachment) Extracoronal (External attachment)  Based on stiffness of the resulting joint Rigid attachments Resilient attachments (Non rigid) www.indiandentalacademy.comwww.indiandentalacademy.com
  17. 17. Based on geometric configuration and design of the attachment. Key and Keyway Interlocks Ball and socket Bar and clip / sleeve Hinge Telescopic Push button Latch Screw units www.indiandentalacademy.comwww.indiandentalacademy.com
  18. 18. M.C. Mensor (1973) Classification according to shape, design and primary area of utilization of attachment. CoronalCoronal RadicularRadicular AccessoryAccessory IntracoronalIntracoronal ExtracoronalExtracoronal Telescope studsTelescope studs (pressure buttons)(pressure buttons) Bar attachmentBar attachment (Bar joints and Bar(Bar joints and Bar units)units) AuxillaryAuxillary Screw unitsScrew units Bar connectorsBar connectors BoltsBolts StabilizersStabilizers BalancesBalances InterlocksInterlocks www.indiandentalacademy.comwww.indiandentalacademy.com
  19. 19. Beccera and others (1987) Intradental attachments - Frictional - Magnetic Extradental attachments - Cantilever attachment - Bar attachment www.indiandentalacademy.comwww.indiandentalacademy.com
  20. 20. ADVANTAGES Improved esthetics and elevated psychological acceptance Mechanical advantage - Direct the forces along the long axis of the teeth / more apically - Force application closer to the fulcrum of the tooth Reduces Non axial loading Decreases Torquing forces Reduces rotational movement of the abutmentwww.indiandentalacademy.comwww.indiandentalacademy.com
  21. 21. In Distal extension base cases – “Broken stress philosophy” Reduced stress to the abutment Stress free rotational/vertical movements Cross arch load transfer and prosthesis stabilization Compared to conventional clasp retained partial denture Less liable to fracture than clasp Less bulky and more esthetics Better retention and stability Less food stagnationwww.indiandentalacademy.comwww.indiandentalacademy.com
  22. 22. DISADVANTAGES Complexity of design, procedures for fabrication & clinical treatment Minimum occlusogingival abutment height (4-6mm) To incorporate attachment without overcontouring Enough length of parallel contact Anatomy of the tooth – Limited faciolingual tooth width (incisor and canine areas) Expensive Complexity of laboratory and clinical procedure Attachment maintenance (repair or periodic replacement) Wearing of attachment componentswww.indiandentalacademy.comwww.indiandentalacademy.com
  23. 23. Require high technical expertise – Dentist and laboratory technician Requires aggressive tooth preparation Cooperation on the part of the patient Difficult to insert and remove Mentally challenged patient Increase demand on oral hygiene performance www.indiandentalacademy.comwww.indiandentalacademy.com
  24. 24. INDICATION / APPLICATIONS OF PRECISION ATTACHMENTS Removable Prosthodontics As a retainer in a removable tooth supported partial denture For esthetic concern in the anterior part of the mouth Stress Breakers – Free end saddles/Distal Extension Base cases (DEB) – When cantilevered pontic is to be used as abutment For movable joints in sectional dentures Periodontal involvement of the tooth Contraindicates rigid FPDs Most efficient bilateral bracing and support are essential www.indiandentalacademy.comwww.indiandentalacademy.com
  25. 25.  Divergent abutment teeth with high survey lines – parallel path of placement.  As a retainers in tooth supported over denture Fixed Prosthodontics  As a connector in fixed partial denture construction (long span bridges)  To overcome alignment problems where abutments have differing path of withdrawal. www.indiandentalacademy.comwww.indiandentalacademy.com
  26. 26. IMPLANT PROSTHODONTICS Implant supported over denture They are used for connection between the tooth and the implant www.indiandentalacademy.comwww.indiandentalacademy.com
  27. 27. CONTRAINDICATIONS OF PRECISION ATTACHMENTS  Poor periodontal support.  Poor crown to root ratio  Poor oral hygiene habits  Abnormally high carious rate  Inadequate space / room to employ the attachment  Compromised endodontic and restorative conditions www.indiandentalacademy.comwww.indiandentalacademy.com
  28. 28. SELECTION OF THE ABUTMENT TEETH Factors : Sound abutment teeth Number of the abutment teeth Location of the abutment teeth Periodontal condition – Crown root ratio – Periodontal support Pulpal status – Vitality of the pulp – Size of the pulpchamber www.indiandentalacademy.comwww.indiandentalacademy.com
  29. 29. Minimum attachment length 4mm Inadequate attachment length < 4mm Maximum attachment length 6-7 mm Axial space requirement Sufficient clinical crown length – for minimum of 4mm attachment length Adequate space between the pulp and the normal contour of the tooth Buccolingual space requirement REQUIREMENTS FOR THE ABUTMENT TEETH www.indiandentalacademy.comwww.indiandentalacademy.com
  30. 30. SELECTION OF THE TYPE OF RETAINER Full crown retainers Intracoronal attachments More retentive / rigid Ideal contours Caries protection Partial coverage retainers Kennedys Cl III partial denture Splinted abutment teeth Most vulnerable Inadequate retention Marginal leakage Inlays / onlays / pin ledges Not used for intracoronal attachments Lack of retention Marginal caries Less life www.indiandentalacademy.comwww.indiandentalacademy.com
  31. 31. Selection of the attachments Intracoronal vs Extracoronal Resilient vs Non resilient 75 mm in length Red  3-4 mm Yellow 5-6 mm Black  7-8 mm EM attachment gauge (Matsuo (1970) www.indiandentalacademy.comwww.indiandentalacademy.com
  32. 32. EM Attachment SelectorEM Attachment Selector System :System :  Mensor, with his EM Attachment selector system, lists 23Mensor, with his EM Attachment selector system, lists 23 attachments in the intracoronal classification. 17 are listed asattachments in the intracoronal classification. 17 are listed as nonresilient types and 5 as resilient types. They range from anonresilient types and 5 as resilient types. They range from a maximum length of 5 to 10mm. The EM attachment Selectormaximum length of 5 to 10mm. The EM attachment Selector system utilizes a colour – coded millimeter attachment gaugesystem utilizes a colour – coded millimeter attachment gauge to define the vertical clearance available in the edentulousto define the vertical clearance available in the edentulous region of occluded casts for attachment selection.region of occluded casts for attachment selection.  The gauge is made of plastic and measures 75mm in length. ItThe gauge is made of plastic and measures 75mm in length. It is graduated from 3 to 8mm in 1mm increments with ais graduated from 3 to 8mm in 1mm increments with a corresponding colour code. Red designates 3 to 4mm ; yellowcorresponding colour code. Red designates 3 to 4mm ; yellow designates 5 to 6mm; and black designates 7 to 8mm.designates 5 to 6mm; and black designates 7 to 8mm. www.indiandentalacademy.comwww.indiandentalacademy.com
  33. 33.  The gauge is placed between the occluded casts adjacent to aThe gauge is placed between the occluded casts adjacent to a tooth that will carry an attachment. The measurement is thustooth that will carry an attachment. The measurement is thus read numerically and according to colour. The vertical limitsread numerically and according to colour. The vertical limits measured by the EM gauge are the common area of concernmeasured by the EM gauge are the common area of concern FOR A CONNECTOR SYSTEM. The available space willFOR A CONNECTOR SYSTEM. The available space will govern the type of attachment system that can be used.govern the type of attachment system that can be used.  A closed vertical space will narrow the selection of availableA closed vertical space will narrow the selection of available or recommended attachments. Where vertical intermaxillaryor recommended attachments. Where vertical intermaxillary space is abundant, the choice of attachment systems can bespace is abundant, the choice of attachment systems can be much less restricting. The EM attachment Selector systemmuch less restricting. The EM attachment Selector system can be used as a guide to attachment selectioncan be used as a guide to attachment selection.. www.indiandentalacademy.comwww.indiandentalacademy.com
  34. 34. INTRACORONAL ATTACHMENTS Intracoronal precision attachment (Dr. Herman E.S Chayes) Precision attachment (prefabricated type) Semiprecision attachments (custom made) Conventional attachment T shaped attachments Modern attachment H shaped attachments Contact plate Adjustment slot Tube Head Reinforcing plate www.indiandentalacademy.comwww.indiandentalacademy.com
  35. 35. Beyeler attachment :Beyeler attachment : Active friction grip attachments :Active friction grip attachments :  In many ways these resemble passive attachments,In many ways these resemble passive attachments, but as they are used in situations where thebut as they are used in situations where the articulation needs to be separated repeatedly eg.articulation needs to be separated repeatedly eg. Removable bridgework they include a spring, usuallyRemovable bridgework they include a spring, usually a split patrix design.a split patrix design.  Used in anterior and premolar regions.Used in anterior and premolar regions. www.indiandentalacademy.comwww.indiandentalacademy.com
  36. 36. MECHANICS OF RETENTION Frictional : Preiskel group I Retention – Surface area contact Function of the length – Controlled by height of clinical crown – Intermaxillary space available Function of cross sectional dimensions Mechanical : Preiskel group II Auxillary mechanical retentive features Ex. Spring loaded plunger / clips www.indiandentalacademy.comwww.indiandentalacademy.com
  37. 37. Passive Attachment : Patrix and Matrix inter lock in a jigsaw fashion..Retention depends on shape of the joint, area of contact and accuracy of fit Channels of passive attachment may be round / elliptical slides DEPENDING ON ARTICULAR RETENTION Passive attachment Active attachment Locked precision attachment Omega Beyelerwww.indiandentalacademy.comwww.indiandentalacademy.com
  38. 38. ACTIVE ATTACHMENT Active friction grip attachment Active snap grip attachments McCollum Crismani Crismani Mc.Collum active friction grip – used in posterior areas and available sizes 4mm and 5.5. mm Crismani active friction grip – available size range 3mm to 7mm used in anterior and premolar areas www.indiandentalacademy.comwww.indiandentalacademy.com
  39. 39. Mc Collum attachment : H shaped attachment Single adjustment slot An H shaped attachment indicated for fixed movable bridgework, removable partial dentures and distal extension partial dentures when cross arch stabilized. www.indiandentalacademy.comwww.indiandentalacademy.com
  40. 40. Stern attachment Two adjustment slots H shaped configuration. This attachment is an intra-coronal, active friction grip attachment to which a distal hinge block has been added. Used as a stress breaker attachment and in fixed removal bridge work and RPDs. www.indiandentalacademy.comwww.indiandentalacademy.com
  41. 41. Crismani attachment : Available as Rigid / Resilient Rigid crismani attachment Frictional grip Mechanical grip These come in resilient and rigid forms. The rigid types are available with both friction and mechanical spring clip retention mechanisms. They come in intracoronal active friction grip as well as snap grip varieties. The hinged, resilient type attachment can be used in distal extension cases. www.indiandentalacademy.comwww.indiandentalacademy.com
  42. 42.  This resilient attachment can be used as a verticalThis resilient attachment can be used as a vertical stress breaker, as a hinged stress breaker, or astress breaker, as a hinged stress breaker, or a combination of both.combination of both.  Two types of resilient crismani attachments areTwo types of resilient crismani attachments are available, one allowing a pure hinge movementavailable, one allowing a pure hinge movement and the other allowing lateral movement inand the other allowing lateral movement in combination with hinge movement.combination with hinge movement. www.indiandentalacademy.comwww.indiandentalacademy.com
  43. 43. Ney’s attachment : Latch retained Conventional H shaped Ney loc split lingual www.indiandentalacademy.comwww.indiandentalacademy.com
  44. 44.  Ney attachments are intracoronal snap gripNey attachments are intracoronal snap grip attachments, available in 2 basic designs, theattachments, available in 2 basic designs, the familiar chayes with adjustable wings and thefamiliar chayes with adjustable wings and the neyloc design with gingival retention feature.neyloc design with gingival retention feature. www.indiandentalacademy.comwww.indiandentalacademy.com
  45. 45. Bakers attachment Schatzmann attachment These are intraconal nonresilient attachments. They come in anterior, bicuspid and molar sizes. H shaped configuration. This attachment is an intra- coronal, active friction grip attachment to which a distal hinge block has been added. Used as a stress breaker attachment and in fixed removal bridge work and RPDs.www.indiandentalacademy.comwww.indiandentalacademy.com
  46. 46. Semiprecision attachments Defined as rigid metalic extension (patrix) of a fixed or removable dental prosthesis that fits into a slot type key way (matrix) in a cast restoration allowing some movement between the component”. - GPT8 Gillete (1923) : The first semiprecision attachment Zinner (1979) Locking semiprecision attachment Non locking semiprecision attachment www.indiandentalacademy.comwww.indiandentalacademy.com
  47. 47. Louis blatter fein (1969) : Four rest seat preparation Occlusal form / outline form – controls amount of rotation Circular Dove tail Rectangular Mortice (Rigid – locking type) Resilient Some resiliency (Non-locking type) Proximal form / side walls – lateral force control Parallel outline Tapering outline The angle of the proximal wall with the gingival floorwww.indiandentalacademy.comwww.indiandentalacademy.com
  48. 48. Gingival floor form : serves the function of reciprocation Flat Inclined Channeled Added reciprocation Mortice occlusal form Rectangular occlusal form www.indiandentalacademy.comwww.indiandentalacademy.com
  49. 49. Advantages : Applied in clinical situations – employing various rest seat outline forms. Variation in tooth size and shapes are easily accommodated. Better crown contour compared to prefabricated type Disadvantages : Long term wear is more – softness of alloy used. No standardization of sizing : Lack of interchangiability of male and female attachment. Greater degree of laboratory skill and attention in detail.www.indiandentalacademy.comwww.indiandentalacademy.com
  50. 50. EXTRACORONAL ATTACHMENTS Introduced by Henry R. Boos (1900) Modified by F Ewing Roach (1908) Application Kennedy’s class I and class II Boitel (1978)  Rigid attachments  Resilient attachments  Bar attachments www.indiandentalacademy.comwww.indiandentalacademy.com
  51. 51. EXTRACORONAL ATTACHMENT Rigid attachments Hinged attachments (Stress breaking action) Resilient attachments ERA O-ring Advantages : • No alteration of contour of the abutment crown • Can be used in short abutment teeth • Greater freedom in the design • Ease of insertion and removal www.indiandentalacademy.comwww.indiandentalacademy.com
  52. 52. Disadvantages (Wolf RE 1980) : Lack of occlusal stability Bulky Rebasing problems Improper control of force distribution Encroachment on the gingival papilla – use of mini attachment www.indiandentalacademy.comwww.indiandentalacademy.com
  53. 53. RIGID EXTRACORONAL ATTACHMENTS Roach attachment (ball and tube attachment) Oldest attachment Patrix – round ball Matrix - tube Pin and tube attachment The simplest Patrix - pin Matrix – tube www.indiandentalacademy.comwww.indiandentalacademy.com
  54. 54. Stabilex attachment Two retention pins Disadvantage is increased length MatrixPatrix Assembled Rigid connection between the male and female units. Additional retention by pins which may be unscrewed and replaced if necessary by a special screwdriver. Attachment is bulky, plaque control difficult > 4mm vertical space required. Application : Situations where generous space avilable www.indiandentalacademy.comwww.indiandentalacademy.com
  55. 55. Conex attachmentConex attachment Sides provides precise path of insertion that resist rotational forces. Pins act two types: Providing frictional retention, mechanical lock. Modified Conex : Enables operator to screw the removable section of prosthesis in place. Application tooth supported prosthesis where adequate plaque control is possible, unilateral distal extension spaces, small restorations for bounded spaces. Bracing arms not required because of the generous lateral surface area of the attachment. www.indiandentalacademy.comwww.indiandentalacademy.com
  56. 56. RESILIENT EXTRA CORONAL ATTACHMENT •Dalbo / Dallabona attachment a) Patrix b) Matrix These are known as Dalla bona slide block or Dalbo stud anchor. They are simple attachments available in non- resilient, resilient and stress broken types. They are useful when there is minimal vertical space available and rotation, reesilience and retention are desired. www.indiandentalacademy.comwww.indiandentalacademy.com
  57. 57. The attachment consists of a single piece maleThe attachment consists of a single piece male stud soldered to the coping and a single unitstud soldered to the coping and a single unit female processed within the denture.female processed within the denture. Types :Types : Rigid cylindrical dolla bonaRigid cylindrical dolla bona Spherical variety (resilient)Spherical variety (resilient) Stress brokenStress broken The stress broken version is similar to theThe stress broken version is similar to the resilient with exception that female housing isresilient with exception that female housing is longer and incorporates a coil spring.longer and incorporates a coil spring. www.indiandentalacademy.comwww.indiandentalacademy.com
  58. 58. Ceka attachment Was developed by Karl Cluytens, 1951 and improved in 1968 Two types - Ceka NV attachment - Ceka revax . Used as a direct retainer in partial dentures and overdentures Is rigid and also non rigid category of extracoronal attachments. According to Waltz 1973 does not seem to have any adverse effect on health of abutment teeth and surrounding tissues. www.indiandentalacademy.comwww.indiandentalacademy.com
  59. 59. ROLE OF ATTACHMENTS AS STRESS BREAKER Rigid system Non-rigid system Stress breaker Broken stress philosophy Mensor  stress can only be selected, altered or blocked “Stress director”www.indiandentalacademy.comwww.indiandentalacademy.com
  60. 60. ASC-52 attachment STRESS BREAKER DESIGNS This is an example of an extracoronal resilient attachment that posses universal resilience. It consists of an extracoronal slide attachment with a spring activated universal hinge joint and adjustable retention. It is the smallest stress director in dentistry and is used for distal extension RPD’s. www.indiandentalacademy.comwww.indiandentalacademy.com
  61. 61. Neys distal extension stress breaker Ney attachments are intracoronal snap grip attachments. Available in 2 basic designs, the familiar chayes with adjustable wings and the neyloc design with gingival retention feature. www.indiandentalacademy.comwww.indiandentalacademy.com
  62. 62. Stern stress breaker H shaped configuration. attachment is an intra-coronal, active friction grip attachment to which a distal hinge block has been added. Used as a stress broken attachment and in fixed removal bridge work and RPDs. www.indiandentalacademy.comwww.indiandentalacademy.com
  63. 63. Extracoronal resilient attachment (ERA) : (ERA) Colour coded retention caps Most flexible White > Orange > Blue > Gray Most rigid Two types of ERA Standard Reduce vertical (ERA – RV) – male part is 0.5mm shorterwww.indiandentalacademy.comwww.indiandentalacademy.com
  64. 64. Matrix Patrix Use of ERA in DEB cases Use in over denture Yen Chen Ku et al (2000) : ERA provides esthetics, vertical resiliency, easy replacement of worn dentures  Vertical resiliency of 0.4mm  Universal joint hinge action www.indiandentalacademy.comwww.indiandentalacademy.com
  65. 65. O-ring attachment Patrix - post with the groove or undercut. Matrix – O-ring synthetic polymer gaskets O-ring are made up of Silicone Nitrile Fluorocarbon Ethylene propylene www.indiandentalacademy.comwww.indiandentalacademy.com
  66. 66. Advantages of O-ring Ease in changing the attachment Wide range of movement Low cost Different degrees of retention Elimination of the time / cost of the superstructure www.indiandentalacademy.comwww.indiandentalacademy.com
  67. 67. STUD ATTACHMENTS (ANCHORS) “Anchor the roots” Simplest of all the attachment Partrix – dowel / post retained restoration Matrix – denture base of the prosthesis Classified as :  Rigid stud unit  Resilient stud unit  Extraradicular units  Intraradicular units Extraradicular Intraradicularwww.indiandentalacademy.comwww.indiandentalacademy.com
  68. 68. Space requirement of these attachment is intermediate between dome shaped coping and thimble shaped coping. These should be placed parallel to the long axis of the tooth. www.indiandentalacademy.comwww.indiandentalacademy.com
  69. 69. DALBO STUD ATTACHMENT Rigid unit Ball and socket unit (Vertical and rotational movement)  ↑ Retention www.indiandentalacademy.comwww.indiandentalacademy.com
  70. 70. ROTHERMAN ECCENTRIC ATTACHMENT It is one of the smallest of stud attachments and hence requires very little space (average bt. 1.6mm). It is available in nonresilient and resilient versions. Simple to use with adequate retention and ease of maintenance. Disadvantages : Chair –side insertion of keyway is difficult. www.indiandentalacademy.comwww.indiandentalacademy.com
  71. 71. ZEST ANCHOR ATTACHMENT Zest anchor is a stud attachment it consists of a metallic funnel shaped tube that is cemented into the root canal of the tooth and a polyethylene stud that is attached to the denture base. The head of the stud squeezes past the construction in the neck of the funnel to retain the denture on the tooth. It derives its retention from within the tooth www.indiandentalacademy.comwww.indiandentalacademy.com
  72. 72. GERBER ATTACHMENT This is one of the largest of the stud units. Provides good retention stability has adjustable springs and it is readily replaceable. Disadvantages : Complex attachment system Requres more space Maintenance problems It permits very little rotational action to torquing of abutment teeth occurs with alveolar resorption . www.indiandentalacademy.comwww.indiandentalacademy.com
  73. 73. SCHUBIGER ATTACHMENT Patrix : threaded post / screw Matrix : recessed collar, cap nut / lock nut Cut section www.indiandentalacademy.comwww.indiandentalacademy.com
  74. 74. BAR ATTACHMENTS Gilmore clip system (1913) - metal bar with retaining sleeve / clip. Bar can be attached to the : Coping or crowns over the vital teeth Post coping on endodontically treated teeth Screwed down into the coping (implant system) Types of bar attachments : Customised bar Dolder bar Ackermann’s bar CM rider bar Hader bar Andrews bar www.indiandentalacademy.comwww.indiandentalacademy.com
  75. 75. Two groups of bar attachments : 1) Bar units - rigid 2) Bar joints – permits rotation Round / circular Oval / egg shaped ‘U’ shaped / parallel sided bars Multiple sleeve bar jointsSingle sleeve bar joints Depending on cross section BAR JOINTS www.indiandentalacademy.comwww.indiandentalacademy.com
  76. 76. DOLDER BAR Egg shaped bar in cross section Open sided sleeve Two sizes 3.5mm x 1.6mm, 3.0mm x 2.2mm Spacer – degree of movement www.indiandentalacademy.comwww.indiandentalacademy.com
  77. 77. MOVEMENTS SEEN IN DOLDER BAR Sagittal rotationRest position Vertical translation Implant supported over denturewww.indiandentalacademy.comwww.indiandentalacademy.com
  78. 78. ACKERMANN BAR Available in different cross section Circular cross section – can be bent in all planes A short extension of 5mm is carried behind the most distal root and the sleeve positioned on this section prevents tendency for distal part to rise when sticky foods are chewed. This is recommended where bar is set an antero-posteriro curve to prevent hinge rotation and motion. Multiple sleeve bar joints are more versatile than single ones except bars that have slightly rigidity.www.indiandentalacademy.comwww.indiandentalacademy.com
  79. 79. CM BAR It is similar to circular Ackermann bar with diameter of 1.9 and is of precious and semi-precious alloys, the latter recommended for long spans. www.indiandentalacademy.comwww.indiandentalacademy.com
  80. 80. HADERBAR Helmut Hader in 1960 Available as a prefabricated plastic pattern Prefabricated plastic pattern are adapted to master cast according to its contour and cast in alloy of choice . Sleeves of plastic have to be replaced for adjustments, hence metal sleeves can be substituted. www.indiandentalacademy.comwww.indiandentalacademy.com
  81. 81. Clips with metal encapsulator Advantage  Prefabricated plastic pattern – no need for soldering.  Precise fit, simplicity. www.indiandentalacademy.comwww.indiandentalacademy.com
  82. 82. Advantages of bar attachments : Rigidly splint the teeth Provides good retention, stability and support Provides cross arch stabilization Positioned close to the alveolar bone (exhibit less leverage) Disadvantages : Bulk of bar Plaque accumulation Wearing Soldering procedure www.indiandentalacademy.comwww.indiandentalacademy.com
  83. 83. MAGNETS AS ATTACHMENT Since 1950 To retain maxillofacial prosthesis Alu, Ni, Iron,Cobalt alloy (alnico) Limited use – larger size 1960 “use of rare earth element” – High field strength – Can be used in smaller size. Somarium cobalt (Sm-Co) (Joseph Becker Hoffer 1967) Neodymium iron boron (Nd-Fe-B) – 20% stronger Somarium iron nitride – High magnetization Used for retention of mandibular overdentures (tooth and implant supported over dentures)www.indiandentalacademy.comwww.indiandentalacademy.com
  84. 84. Gilling’s magnetic attachment (cobalt somarium alloy magnets) “Split pole paired magnets” Closed field magnetic system Magnetic retainer with magnets Magnetic keeper www.indiandentalacademy.comwww.indiandentalacademy.com
  85. 85. Advantages of magnetic attachment : Smaller size and strong attractive force Produce constant force – constant retention Easy to incorporate into the prosthesis Automatic reseating Boon for elderly patients (Parkinsonism, arthritic patient) Less lateral force to the abutment tooth www.indiandentalacademy.comwww.indiandentalacademy.com
  86. 86. Jackson magnetic attachment (cobalt somarium alloy magnets) Cemented in keeper Screwed in keeper www.indiandentalacademy.comwww.indiandentalacademy.com
  87. 87. Disadvantages : Loss of retention due to corrosion or heat instability Requires encapsulation within inert alloys Cannot be repaired High cost Limited force transmission - Magnets can slide on their keepers. www.indiandentalacademy.comwww.indiandentalacademy.com
  88. 88. AUXILLARY ATTACHMENTS  Screw and tube attachment  Key and keyway / interlocks  Presso Matic or Isoclip  Bar connectors  Attachments for sectional dentures / bolts Screw and tube attachment www.indiandentalacademy.comwww.indiandentalacademy.com
  89. 89. Indications : To overcome alignment problems Connecting one restoration of fixed partial denture to another Allowing the removal of long span fixed partial denture for repair and examination of abutment. www.indiandentalacademy.comwww.indiandentalacademy.com
  90. 90. ATTACHMENT USED FOR SECTIONAL DENTURES Two part dentures : One part - chrome cobalt base Second part - removable acrylic flange with teeth Advantage of superior esthetics and improved retention Method of union : Physical interference : Bolt retained prosthesis Frictional resistance : Split post retained prosthesis www.indiandentalacademy.comwww.indiandentalacademy.com
  91. 91. SECTIONAL DESIGNS Individual sections / separate sections : uses mesial and distal surface of the abutment teeth as guiding planes. www.indiandentalacademy.comwww.indiandentalacademy.com
  92. 92. www.indiandentalacademy.comwww.indiandentalacademy.com
  93. 93.  For critical analysis of these attachments, the need forFor critical analysis of these attachments, the need for through knowledge of their principles andthrough knowledge of their principles and applications may be of help in obtaining a betterapplications may be of help in obtaining a better insight into their drawback and areas of potentialinsight into their drawback and areas of potential improvement.improvement.  The attachment-retainer removable partial dentureThe attachment-retainer removable partial denture presents a challenge in technical skill andpresents a challenge in technical skill and understanding of the biomechanics of maxillo-understanding of the biomechanics of maxillo- mandibular function.mandibular function.  The main functions of the attachments are retention,The main functions of the attachments are retention, stress reduction and concealment for estheticstress reduction and concealment for esthetic purposes. The attachment-retained removable partialpurposes. The attachment-retained removable partial denture does attempt to return the patient to as neardenture does attempt to return the patient to as near normal function and appearance as possible.normal function and appearance as possible. www.indiandentalacademy.comwww.indiandentalacademy.com
  94. 94. Advanced removable partial dentures. James S. Brudvick Quint Int. Pub Pg. 115-152. Contemporary fixed prosthodontics. Rosensteil, Third edition, Mosby Pub., pg. 543-566. Overdenture made easy guide to implant and root supported prosthesis Harold W. Preiskel – George Zarb. Precision attachments – a link to successful restorative treatment Gareth Jenkins Quint Publishing. Theory and practice of precision attachment RPD – James L Baker Richard J Goodkins. www.indiandentalacademy.comwww.indiandentalacademy.com
  95. 95. J Prosthet Dent 1973; 29(5): 494-497 J Prosthet Dent 1973; 29(2): 165-171. J Prosthet Dent 1987; 58(3): 327-327. DCNA 1970; 14(3): 595-601. Quint Int 2000; 31(5): 311-317. Quint Int 1987; 18(1): 4-51 J Prosthet Dent 2001; 86: 137-42 J Prosthet Dent 1981; 45(1): 37-43. Int J Prosthet 1990; 3(1): 98-102. Int J Prosthet 1990; 3(2): 165-173. www.indiandentalacademy.comwww.indiandentalacademy.com
  96. 96. www.indiandentalacademy.comwww.indiandentalacademy.com

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