5-Precision attachments.pptx dentistry NDS

Precision attatchment-dentistry

1. Precision attachments Presented by: Dr. Sneha Ailsinghani 1 st year PG Department of Prosthodontics 12/18/2019 1

2. Contents Introduction Attachment History of attachments Classification of attachment systems Intracoronal attachments Extracoronal attachments 12/18/2019 2

3. Stud attachments Bar attachments Magnetic retainers Auxillary attachments Attachment selection Conclusion 12/18/2019 3

4. Introduction In the present society, patients approach a dentist for two main reasons; discomfort or esthetics Attachments are used as alternative to clasps in removable partial denture therapy, which gives both esthetic and functional outcome The correct use of attachments may overcome both physical and psychological problems associated with conventional RPD designs 12/18/2019 4

5. Attachment A mechanical device for the fixation, retention, and stabilization of a prosthesis; OR a retainer consisting of a metal receptacle and a closely fitting part; the former (matrix component) is usually contained within the normal or expanded contours of the crown of the abutment tooth and the latter ( patrix component), is attached to a pontic or the denture framework 12/18/2019 5 GPT9

6. Attachments act as stress redirectors and absorbers. Their function is to preserve soft tissue and bone as well as provide retention The direct retention function of precision attachments prove to be more efficient than clasps 12/18/2019 6 Kanathila H. et al., An insight into various attachments used in prosthodontics : A review, International Journal of Applied Dental Sciences, 2018; 4(4): 157-160

7. History of attachments 12/18/2019 7 Kanathila H. et al., An insight into various attachments used in prosthodontics : A review, International Journal of Applied Dental Sciences, 2018; 4(4): 157-160

8. 12/18/2019 8 Kanathila H. et al., An insight into various attachments used in prosthodontics : A review, International Journal of Applied Dental Sciences, 2018; 4(4): 157-160

9. Classification of attachment systems 1. Based on their method of fabrication and the tolerance of fit between the components A. Precision attachment- They are prefabricated machined components with precisely manufactured metal to metal parts with close tolerance. B. Semi precision attachment- They are laboratory made or custom made type. The components usually originate as prefabricated or manufactured patterns (made of plastic, nylon or wax) or Hand waxed 12/18/2019 9 Kanathila H. et al., An insight into various attachments used in prosthodontics : A review, International Journal of Applied Dental Sciences, 2018; 4(4): 157-160

10. Semi-precision attachments: A laboratory fabricated rigid metallic patrix of a fixed or removable partial denture that fits into a matrix in a cast restoration, allowing some movement between the components; attachments with plastic components are often called semi-precision attachments even if prefabricated (not laboratory fabricated) 12/18/2019 10 GPT9

11. 2. Based on shape, design and primary area of utilization of attachment (Mensor-1973) 12/18/2019 11 Mensor MC. Classification and selection of attachments. J Prosthet Dent. 1973; 29:494-97

12. Precision attachments According to GPT 9- An interlocking device, one component of which is fixed to an abutment or abutments, and the other is integrated into a removable partial denture Cohn states, “The precision attachment prevents lateral stress to the periodontium of the abutment teeth when inserting or removing the denture. It distributes stress vertically to the tooth during function and stabilizes the abutment teeth against lateral stress” 12/18/2019 12 GPT9 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

13. Intracoronal attachments Flange and slot Provide rigid connection between the two sections of prosthesis 12/18/2019 13 a . Those whose retention is entirely frictional . The McCollum intracoronal unit b. Those whose retention is augmented by a mechanical lock The Schatzmann unit . Additional retention is provided by a spring-loaded plunger Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books.

14. Most intracoronal attachments consist of a parallel-sided flange engaging a slot Vertical space of at least 4 mm and buccolingual space of 3 mm is usually required Small bounded spaces, with appreciable bone loss, may be restored with intracoronal attachments 12/18/2019 14 Making the prosthesis removable simplifies oral hygiene practice and allows artificial mucosa to replace missing bone Preiskel H.W. Precision attachments for partially dentate mouth, Annals of the Royal College of Surgeons of England (I974), vol 55, 294-298

15. Henderson and Steffel have noted that “ the intracoronal attachment has two major advantages over the extracoronal attachments, which is the elimination of a visible retentive component and vertical support through rest seat locked more favourable in relation to the horizontal axis of the abutment tooth. It provides some horizontal stabilization similar to that of an internal rest, but some additional bracing extracoronally is usually desirable” 12/18/2019 15 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

16. Development of intracoronal precision attachments Prior to manufacturing of intracoronal attachments, the early attachments were bent, cut and soldered into shape Early intracoronal retainers were split-bar attachment, tube and split-post attachment, solid-post and tube attachment and the winged lug attachment 12/18/2019 16 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

17. 12/18/2019 17 Winged lug attachment : the male element is made with a strip of clasp gold gauge no. 22 by doubling on itself. The female box is made using platinum gauge no. 40. An oval shaped plate made out of 38 or 30 gauge platinum; 22-carat gold is soldered on top of male to prevent food entrapment between male and female elements Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

18. 12/18/2019 18 The Roach attachment : an extracoronal type of attachment based on the ball and socket principle Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

19. 12/18/2019 19 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

20. 12/18/2019 20 Gollobin and Bernstein’s split-bar bridge attachment The split-post and bar attachment Iridoplatinum spilt bar with a V-shaped flange. The split-bar ends with a split-post, to which the bar acts in the relationship of a shank. The combined split bar and posts fit into a platinum box in the abutment restoration. The end of the spilt bar attaches to the partial denture Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

21. 12/18/2019 21 The Morgan attachment . A precursor of the Chayes attachment, employing a parallel jig to parallel and hold the attachments in position while being soldered to the abutment castings

22. 12/18/2019 22 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books The Chayes attachment (1906). Anchorage section exhibits a post with a seam in the centre. This seam allows it to be expanded or tightened to the hood

23. 12/18/2019 23 An attachment system designed by Alexander at the end of 19 th century. The male sections were joined to the crowns, the attachments were tapered and used with a buccolingual path of insertion for the prosthesis Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

24. 12/18/2019 24 Retention Surface area of contact between the two parts Cross-section of male part x length of the male part Limited as female part should recess within the circumference of the tooth Governed by the height of the clinical crown Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

25. 12/18/2019 25 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books Cross-sections of various types of attachments. The H-shaped flanges are stronger and have nearly double the contact surface area of the earlier T-shaped flanges. Attachments with circular cross-section are suitable only for joining two sections of a fixed prosthesis.

26. Frictional fit intracoronal attachments with adjustment potential Constant insertion and removal of the prosthesis will cause the attachments to wear, so that some form of adjustment is desirable 12/18/2019 26 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books The male and female parts of the Stern G/A attachment.

27. Crismani series of intracoronal attachments 12/18/2019 27 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books The narrower(2.8mm) Crismani unit features a central groove for adjustment Chamfer and tapered gingival male section to facilitate insertion

28. The wider Crismani units incorporate a wire clip to increase retention Access to the clip is obtained by removing the screw in the male unit Failure to tighten the screw correctly will prevent the male unit sliding into place The female unit consist of two depressions for the retaining wire and is 7mm tall. 12/18/2019 28 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

29. 12/18/2019 29 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books a. The redesigned McCollum attachment . b. The McCollum for use with conventional yellow golds c. The McCollum for use with bonded gold to porcelain techniques

30. The Ancra intracoronal attachment unit features an ‘H’ shaped profile with external frictional flange, while the male unit incorporates slots either side to allow for modification of retention. 12/18/2019 30 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

31. 12/18/2019 31 The T- Geschiebe 123 intracoronal attachment Cast bracing arm and external frictional flange Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

32. The Biloc by Cendres and Metaux , has a plastic pattern with the female element, that is burnt out with the wax model the abutment crown The male element is prefabricated of a platinised gold alloy. The basic ‘H’ shape is modified with the internal flange resembling two lobes with a small groove between them Bracing arm is recommended for this unit 12/18/2019 32 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

33. Auxillary retentive features Incorporated to provide more retention for a given contact area, although no extra stability is provided A minimum of 4mm vertical space is still usually necessary 12/18/2019 33 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

34. The Schatzmann series include a spring loaded plunger within the male part, engaging a depression in the female element Applications are limited by their bulk 12/18/2019 34 The largest of the Schatzmann series features a dismantling screw around the spring loaded plunger Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books Female element include a retraction groove to engage the plunger within the male component

35. 12/18/2019 35 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books The modified plunger is held in place by the screw inserted through the base of the attachment The smaller Schatzmann attachment Processing screw to prevent movement during processing procedures

36. The Stern gingival latch attachment The base of the male unit is split and formed in the shape of a door latch The retention is adjusted by opening out the base of the male unit with a purpose built tool Two sizes- standard and miniature 12/18/2019 36 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

37. Other modifications: Micro : smallest of the intracoronal attachments with auxillary retention. Squared lateral surfaces, allowing the buccolingual dimensions to be reduced Dovetail and ES 1 : modifications of the tagging of the male unit Jacket Maintenance System (Stern): male section is covered by nylon jacket that eliminates wear of either metal components Yellow jacket- frictional retention Red jacket- adds a light latch action Black jacket- features a strong latch action 12/18/2019 37 The adjustment instrument for the Stern G/L attachment Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

38. Friction fit intracoronal attachments without adjustment potential Repeated removal and insertion will cause the attachment to wear-unsuitable for removable prosthesis Useful for joining a series of crowns without a common path of insertion 12/18/2019 38 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

39. 12/18/2019 39 Round profiles are useful where anterior teeth are concerned Beyeler attachment for use in posterior quadrants. Offers more contact surface area Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

40. Wang CH et al. (2005), observed the connecting rigidities of four precision attachments, the dovetail slide attachment beyeler , cylindrical slide attachment, Spang Stabilex and Mini SG with the conical crown retained telescope (CCT) The largest of the mesial end displacements when horizontally loaded was as large as 44.5 µm with dovetail slide beyeler , the same phenomena occurred with the distal end displacements when horizontally loaded, followed sequentially by the Spang Stabilex , CCT, cylindrical slide and the Mini SG Thus, connecting rigidities of rigid precision attachments are very similar to CCT, and only the dovetail slide beyeler attachment is too weak to resist horizontal displacement force 12/18/2019 40 Wang CH. et al., Connecting rigidities of various precision attachments compared with the conical crown retained telescope, Kaohsiung J Med Sci January 2005, Vol 21,No 1

41. Abutment tooth preparation Survey the diagnostic cast to ensure proper placement of the required precision attachment for esthetics , periodontal health, restoration of biologic tooth contours, and an optimal path of insertion of the RPD Prepare guide planes to avoid an overcontoured restoration on these surfaces of the subsequent restoration Prepare a box or deep recess to house the precision attachment rest seat so as to avoid an overbuilt casting 12/18/2019 41 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

42. Prepare the entire abutment tooth using a full shoulder with a bevel type of preparation. When preparing a tooth for any intracoronal attachment, whether a precision or a semi-precision attachment, the dentist must deepen the shoulder from the mid-point on the buccal surface to the midpoint on the lingual surface, on the near-proximal zone Add grooves or boxes to increase the resistance to dislodgement on short crowned abutment preparation or on those ravaged by caries or large previous restorations 12/18/2019 42 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

43. Guidelines for utilization intracoronal precision attachments Selected abutment teeth should be splinted together for proper distribution of forces for use in precision attachment type RPD Use of minimum of 2/3 rd of the attachment The length of the attachment is more important than the width. A full-length, narrow attachment is preferable to a short, wide attachment 12/18/2019 43 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

44. If attachment length is less than 5mm, another type of intracoronal attachment must be substituted as there will be insufficient length for the optimal utilization of the precision attachment Prepare the abutment tooth sufficiently, so that the rest seat portion is maintained within the normal confines of the crown contours for proper periodontal health 12/18/2019 44 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

45. All of the precision attachments utilized should be of equal length. When this is not feasible, pairs of precision attachments on similar teeth bilaterally should be equal length At no time should a rest be grounded or relieved to make it fit. To achieve a proper fit, clinical and laboratory procedures must be followed precisely. The attachments must be parallel to each other to avoid improper fit, mutilation, and torquing of abutments 12/18/2019 45 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

46. Uses and advantages of intracoronal precision attachments Connectors : sections of a fixed prosthesis may be joined with precision attachments to facilitate parallelism of abutment teeth, ease of cementation and avoidance of torque on full-arch restoration Questionable prognosis : when the prognosis of a segment of fixed partial prosthesis is questionable, this section can be joined to the part of the prosthesis with a more favourable prognosis by precision attachments. If this segment should be lost, it can be replaced with an attachment-retained, removable partial denture 12/18/2019 46 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

47. Aesthetics (tooth-borne RPD): precision attachments allow for the construction of an aesthetic partial denture that retains the appliance dislodging forces without damage to the abutment teeth and aids in resisting any tendency of the denture to be displaced horizontally. In addition, the partial denture enables the dentist to achieve a cross-arch stabilization Precision attachments : these have more advantageous force distribution to abutment 12/18/2019 47 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

48. Ease of repair : when the rest portion of the attachment fractures, the appliance can be repaired easily. This is accomplished by selecting the size and make of the attachment that was originally utilized and fitting this into the rest seat. 12/18/2019 48 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

49. Disadvantages of intracoronal precision attachments Lack of rotational movement Complicated clinical and laboratory procedures Increased cost to patient Limited in use owing to large pulp size and length of clinical crown 12/18/2019 49 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

50. When used properly, intracoronal precision attachments in conjunction with fixed partial prosthesis offer the dentist as well as the patient an optimal result in the rehabilitation of the compromised dentition 12/18/2019 50 Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415

51. Extracoronal attachments Unlike intracoronal attachments these units need no space within the abutment crown and are unrestricted by pulpal considerations. They may be employed where buccolingual space is limited-particularly useful where lower canines are the most distal abutments. 3 groups of extracoronal attachments: Projection units Connecting units Combined units 12/18/2019 51 Preiskel H.W. Precision attachments for partially dentate mouth, Annals of the Royal College of Surgeons of England (I974), vol 55, 294-298

52. Projection units Largest and most popular Since they project from the abutment crowns, no box preparation is required but they complicate plaque control Rigid projection units Projection units allowing play between two sections 12/18/2019 52 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

53. 12/18/2019 53 The height of the projection governs the length of the path of insertion, influences the retention available and its ability to resist rotational loads around a sagittal axis The lateral surface area counteracts side-to-side movements of denture base The width affects its strength and also provides bulk for incorporation of retaining devices

54. 12/18/2019 54 The shape of the unit should be modified to prevent sliding or undesirable tilting movements

55. Drawbacks of long attachments: Problems of plaque control increase with increase in length of unit Greater length requires more space within the prosthesis. If the attachment is not aligned with the long axis of edentulous ridge, the longer attachment may produce an unacceptable lingual bulge in the prosthesis Although they do not require large box or shoulder preparations, some space within the crown contour is required for the retaining plate 12/18/2019 55

56. 12/18/2019 56 Rounding the base of the attachment

57. 12/18/2019 57 The Stabilex attachment Screwdriver for changing the pins Provides extremely effective retention, but is bulky Plaque control is difficult as it requires more than 4mm of vertical space. Cannot be placed in case limited space availability

58. 12/18/2019 58 The Conex attachment . A series of refinement has reduced its bulk, facilitated plaque control and improved retention Two models of retaining pin- frictional retention or an additional mechanical lock that further improves retention

59. 12/18/2019 59 Special separation device Conex adujsting tool

60. 12/18/2019 60 Additional tagging may be bolted to the Conex female unit. Modified Conex Component parts of modified Conex attachment

61. 12/18/2019 61 The Scott attachment . The projecting unit may be placed away from the gingival margins. This unit may be obtained as a plastic blank and cut to size on the master cast Requirements: abutments of adequate strength and sufficient vertical and buccolingual space for the attachment

62. 12/18/2019 62 The Dalbo attachment The bilateral model The unilateral model Contact between the vertical surfaces prevents the distal denture rotating away from mucosa Contact between lateral facing surfaces provides resistance to lateral forces

63. 12/18/2019 63 The Shoulder Dalbo Cut-away view of the Shoulder Dalbo without occlusal load Under occlusal load vertical travel is limited by contact of the shoulder Metal spacer

64. 12/18/2019 64 The Pin- Dalbo Slight lingual twist simplifies plaque control The miniature Dalbo Unilateral model used

65. A study reported by Caputo AP et al. (1981), showed stress patterns resulting from the use of a Dalbo , Thompson dowel rest and Sterns attachment with a distal extension type of prosthesis. With a single abutment, there was too much stress on the apical one third of the abutment tooth. Most apical stress was with Sterns attachment and least for splinted teeth with Thompson dowel rest attachment If a single abutment tooth was employed, a Dalbo extracoronal attachment showed the least stress. 12/18/2019 65 Caputo AP et al., Photoelastic analysis of stress patterns on teeth and bone with attachment retainers for removable partial dentures, J Prosthet Dent, 46:21, 1981

66. 12/18/2019 66 The Ceka attachment At rest Under vertical load Under rotational load

67. 12/18/2019 67 The rigid pin assembly 5mm vertical space Modified design with bracing arm and occlusal rest 600 series (resilient) 600 series for soldering to denture framework 600 series for burying in acrylic resin

68. 12/18/2019 68 300 series- ‘S’ type designed for soldering to the framework The KS type designed to be buried in the acrylic resin of the denture base and includes retaining tags that may be bent to reduce space requirement Attachment bolted to the minor connector of the partial denture The KS type-yellow gold or SS Base of retention pin bolted to denture connector

69. 12/18/2019 69 Mini retaining unit The ‘OL’ series The Ceka Lo-Cast attachment with black plate Red patterns

70. 12/18/2019 70 Bracing arm Mandrel for alignment in vertical plane Metal frame work surrounds the attachment simplifying plaque control and contributes to strength Special instrument for producing fine finish to the metal surround of the attachment The Ceka adjustment kit provided for dental surgeons

71. 12/18/2019 71 Wedged shaped instrument for increasing retention- move side-to-side Never lever apart the leaves of the pins

72. Connecting units These units connect two parts of a removable prosthesis, allowing a certain limited amount of play They have a similar function to a long and flexible major connector, but act in a more precise and predictable manner 12/18/2019 72 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

73. 12/18/2019 73 The Axial Rotation joint . The small window around the screw determines the vertical travel allowed by the joint For distal extension dentures The Rotation joint allows no vertical play between the two sections of the attachment For tooth supported dentures Steiger joints Metal trimmed only from the mesio -gingival and disto-oclusal sections of the male unit.

74. Combined attachments These units consist of a hinge connector joined to an intracoronal attachment. Hinge unit is buried within the denture so that when it is in position, the attachment closely resembles a rigid intracoronal attachment Complex, cumbersome and has limited applications 12/18/2019 74 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

75. 12/18/2019 75 Combined Crismani unit Bilateral configuartion - lateral walls of the projection are slightly tapered Unilateral configuration- lateral walls of the projection are virtually parallel

76. Daas M. et al. (2008) evaluated the influence of the retention mechanism on the behavior of a mandibular implant-retained overdenture (IRO) during the simulation of mastication Three foodstuff positions were analyzed for two retention mechanisms, “resilient” or “rigid” The “resilient” configuration provided a wider contact area between the mucosa of the denture bearing area and the prosthesis. An increase of the mastication force transiting through the mucosa was also noted and lower stresses were observed in the bone surrounding implants They concluded that the resilient attachments allowed for an increase of the mastication load transiting through denture bearing surface 12/18/2019 76 Daas M. et al., complete finite element model of a mandibular implant-retained overdenture with two implants: Comparison between rigid and resilient attachment configurations, Medical Engineering & Physics 30 (2008 ) 2 18–225

77. Wang H et al. (2011), compared the mechanical effects of 2 types of extracoronal attachments (rigid and nonrigid ) in distal extension removable partial prostheses on the alveolar ridge and abutment tooth periodontal ligament They concluded that stress on the terminal abutment can be reduced by the use of an extracoronal resilient attachment that allocates more loads onto the distal edentulous ridge. Lateral force has the greatest effect on the terminal abutment in distal extension base PRDPs with universal hinge attachments. Movement of the component parts in the attachment is most affected by buccolingual loading. 12/18/2019 77 Wang H et al., Effects of rigid and nonrigid extracoronal attachments on supporting tissues in extension base partial removable dental prostheses: A nonlinear finite element study, J Prosthet Dent 2011;105:338-346

78. Rivaldo EG et al. (2011), evaluated the retentive ability and weight change of two extracoronal attachments, one with plastic inserts and the other with conventional metal-alloy after repeated insertion/removal cycles They concluded that metal-alloy precision attachments showed a greater increase in retentive ability compared to precision attachment with plastic inserts over time and both precision attachments did not show weight change after five years of simulated use. 12/18/2019 78 Rivaldo EG et al., “In vitro” wear behavior of extracoronal precision attachments, Stomatos , Vol. 17, N.33, July/Dec. 2011

79. Stud attachments These attachments are so called because the shape of the male units that are usually soldered to the diaphragm of a post crown Some of these units provide a rigid connection, others allow movement between the two sections 12/18/2019 79 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books

80. 12/18/2019 80 Microflix Extraradicular - male element projects form the root surface of the preparation or implant Prieskel HW. Overdenture made easy A guide to implant and root supported prosthesis, 1996, Quintessence Books

81. 12/18/2019 81 The Ceka Revax Intraradicular - male element forms part of the denture base and engages a specially produced depression within the root contour or implant

82. 12/18/2019 82

83. 12/18/2019 83 The Revax system, can be employed in conjunction with rigid bar stabilizer for the retention of implant supported overdentures

84. 12/18/2019 84 O-Ring

85. 12/18/2019 85 Most attachments need to be buried within the acrylic resin

86. 12/18/2019 86

87. 12/18/2019 87 The Zest intracoronal unit with comprehensive kit The seating tool and cropping instrument Extensive preparation of the internal aspect of the root

88. 12/18/2019 88 The ERA system . Color coded resin units provide varying degrees of retention ERA retainer within an overdenture Most flexible white>orange>blue>gray Most rigid

89. 12/18/2019 89 The Pro Snap by Metaux Precieux with replacable retention elements providing 8, 10, 12 Newtons . The male unit is cast on The Pro Fix -conventional stud retainer

90. 12/18/2019 90 The Gerber unit The Locator retention system . Retention is provided by a replaceable resin component within the female section Dalbo ‘Elliptical’ stud retention system

91. 12/18/2019 91 The Rothermann unit

92. Selection of stud attachments Space must exist for these units to be surrounded by a reasonable thickness of acrylic resin, otherwise the denture will be weakened Restricted buccolingual space-metal lingual connector employed Additional space may be provided by osseous recontouring and mucogingival surgery, allowing the level of attachment to be reduced When vertical space is restricted for implant supported prosthesis, select an alternative and less space consuming retaining system such as a bar 12/18/2019 92 Prieskel HW. Overdenture made easy A guide to implant and root supported prosthesis, 1996, Quintessence Books

93. The more rigid attachments occupy more vertical space than the ball and socket variety Dome shaped copings occupy the minimum space and leverages applied must be small In class II div 2 malocclusion, retroclined anterior teeth encroach upon the space available. Where buccolingual space permits, attachments for the lower restorations can be placed 1-2mm lingual to their normal position 12/18/2019 93 Designs with flattened studs minimize vertical space requirements

94. 12/18/2019 94 Connecting adjacent copings resist rotational forces and inclined forces resolve along the long axes of the roots Conflicting undercuts- base extension must be reduced, this will compromise stiffness and retention. A metal denture base is preferred

95. The alignment of stud attachments 3 considerations: The alignment of stud attachments with one another The alignment of stud attachments with the path of insertion of the denture The taller the attachment, the more difficult the alignment may be Significant divergence of roots or implants should be considered contraindication 12/18/2019 95 Prieskel HW. Overdenture made easy A guide to implant and root supported prosthesis, 1996, Quintessence Books

96. The number of attachments One stud attachment on each side of the arch, remaining roots can be covered with simple copings Increasing the no. of attachments does not increase retention, it may contribute to improved stability but weakens the structure and also difficult to clean and maintain Exceptions include nylon attachments 12/18/2019 96 Prieskel HW. Overdenture made easy A guide to implant and root supported prosthesis, 1996, Quintessence Books

97. 12/18/2019 97 Dummy male component incorporated in the cast The dummy Dalbo stud retainer The dummy Microfix stud retainer When necessary to locate an attachment directly to the denture, cut a vent hole. Self polymerizing acrylic resin is applied through the hole

98. Kim S et al. (2015), compare the changes in retentive force of stud attachments, Kerator blue, O-ring red, and EZ lock for implant overdentures by in vitro 2-year–wear simulation Results revealed the highest value for Kerator , followed by the O-ring and EZ lock attachments. However, no significant difference was detected between Kerator and O-ring after 2500 insertion and removal cycles, the highest retention loss was recorded for O-ring , and no significant difference between Kerator and EZ lock. 12/18/2019 98 Kim S et al., Comparison of changes in retentive force of three stud attachments for implant overdentures , J Adv Prosthodont 2015;7:303-11

99. Also, Kerator showed the highest retentive force , followed by EZ lock and O-ring, after 2500 cycles. Based on SEM analysis, the polymeric components in O-ring and Kerator were observed to exhibit surface wear and deformation Conclusion-After 2500 insertion and removal cycles, all attachments exhibited significant loss in retention 12/18/2019 99

100. Aroso C et al. (2016), conducted a study to evaluate the durability of and variations in the retention force of three implant overdenture stud-type attachment systems at three different angulations in an aqueous environment of artificial saliva. Three commercial attachment systems were selected for the study: Clix , Dalbo -Plus and Locator The abutments were placed at angulations of 0°, 10°and 20° 12/18/2019 100 Aroso C et al., Effect of abutment angulation in the retention and durability of three overdenture attachment systems: An in vitro study, J Adv Prosthodont 2016;8:21-9

101. Results revealed that the greater angulation of the abutment values were found to influence the retention capacity of the attachments, the attachment systems evaluated presented adequate retention for clinical usage, the fatigue test simulating 5 years of denture insertion and removal did not produce wear in metal abutments Overall, the Dalbo - Plus system provided the best retention followed by the white Locator system. 12/18/2019 101 Aroso C et al., Effect of abutment angulation in the retention and durability of three overdenture attachment systems: An in vitro study, J Adv Prosthodont 2016;8:21-9

102. Mahrous AI et al (2015), compared and evaluated the effect of two different attachments (locator attachment and ball and socket [B&S] attachment) on implants and natural abutments supporting structures, in cases of limited inter-arch spaces in mandibular Kennedy Class I implant supported removable partial over dentures by measuring the bone height changes through the cone beam radiographic technology The side of the implant-supported partial over denture restored with the locator attachment showed better effect on bone health around both the placed dental implant and the main natural abutment as compared with the B&S attachment 12/18/2019 102 Mahrous AI et al., Implant Supported Distal Extension over Denture Retained by Two Types of Attachments. A Comparative Radiographic Study by Cone Beam Computed Tomography, Journal of International Oral Health 2015; 7(5):5-10

103. Bar attachments Consist of a bar spanning an edentulous area joining teeth or roots The denture fits over the bar and is connected to it with one or more sleeves 12/18/2019 103 Bar attachment connected to root filled teeth Bar attachment connected to Branemark implant copings

104. 12/18/2019 104 The Dolder Bar Joint , having single sleeve joint allowing vertical and rotational movements Bar unit . The sleeve/ bar junction is rigid

105. Complications of bar attachments Vertical and buccolingual space requirements limit the applications Require more plaque removal skill on the part of the patient than most other retainers Require adequate and equal retention for abutment retainers if cementation failures are to be avoided Requires technical skills together with clinical expertise. Rebasing and repair can be complicated 12/18/2019 105

106. 12/18/2019 106 Occlusal stops provided as leverage potential is high when cantilever employed

107. Bar joints 12/18/2019 107 Dolder bar joint. Open sided single sleeve Single sleeve bar joint

108. 12/18/2019 108 Multiple sleeve bar joint The connection between the abutments must be rigid The use of cantilevered extensions requires at least four implant abutments. Small retentive clips vulnerable to overload

109. 12/18/2019 109 Round/ circular shaped Oval/egg shaped ‘U’ shaped / parallel sided bars Gilmore Ackermann and derivative bars- multiple sleeve systems

110. 12/18/2019 110 Sleeves of Ackermann bar project buccolingually Retention tags for Ackermann bar

111. 12/18/2019 111 The C.M. bar Hader bar Special space maintaining device Special handling device for the sleeve

112. 12/18/2019 112 Standard abutments can be employed when implants are only moderately misaligned Angled abutments are far from ideal but connecting them minimizes the effects of non-axial loads

113. Mohammad D.H. et al. (2013) compared two types of attachments (bar and ball systems) on the basis of the stresses introduced to the mandibular posterior residual ridge by an overdenture retained by two implants. He found that the bar-retained overdenture introduced higher stresses to the posterior mandibular residual ridge compared to the ball-retained overdenture (0.4 MPa and 0.1 MPa , respectively) 12/18/2019 113 Mohammad D.H. et al., The effects of two attachment types on the stresses introduced to the mandibular residual ridge, Quintessence Int, 2013, vol. 44 no. 8, 555-634

114. Petropoulus V.C. , Mante F.,(2011) compared the retentive forces and strain energies of the Nobel Biocare standard ball, Nobel Biocare newer generation ball (Yorba Linda, CA), Zest Anchor, Zest Anchor Advanced Generation (Escondido, CA), Sterngold-Implamed ERA white, and Sterngold-Implamed orange attachments (Attleboro, MA) on an implant-retained in vitro overdenture model Results revealed that the Zest Anchor Advanced Generation attachment had significantly the highest retentive vertical and oblique forces. The Zest Anchor had the lowest vertical force , and Nobel Biocare Standard had the lowest oblique retentive force.. 12/18/2019 114 Petropoulus V.C., Mante F., Comparison of Retention and Strain Energies of Stud Attachments for Implant Overdentures , Journal of Prosthodontics 20 (2011) 286–293 by the American College of Prosthodontists

115. The Nobel Biocare Standard Ball attachment had the highest strain energies in the vertical and oblique directions. The Sterngold-Implamed ERA White and Zest Anchor had the lowest strain energies, in the vertical and oblique directions He concluded that the retentive forces and strain energies of implant overdenture stud attachments are different and should be considered during prosthesis selection 12/18/2019 115 Petropoulus V.C., Mante F., Comparison of Retention and Strain Energies of Stud Attachments for Implant Overdentures , Journal of Prosthodontics 20 (2011) 286–293 by the American College of Prosthodontists

116. Silva AS et al. (2015), compared the durability and retention of 4 types of attachments, Hader Yellow, Hader Red, Ackerman Gold and Ackerman Stainless Steel, placed over computer aided design/computer aided manufacturing (CAD/CAM) titanium bars when subjected to different pH conditions All the attachments lost retention (insertion/removal) over time. The more acidic pH value (pH 4) caused a significant decrease in the average values of the insertion and removal forces of all the attachments 12/18/2019 116 Silva AS et al., The influence of saliva pH value on the retention and durability of bar-clip attachments, J Adv Prosthodont 2015;7:32-8

117. The attachment with the most stable behavior was the Ackerman Gold . The Ackerman Stainless Steel was the attachment with the highest values of insertion and removal initially. The highest percentage of loss retention after 5400 cycles was observed in the Ackerman Stainless Steel attachment (pH 4), with 91.47% 12/18/2019 117 Silva AS et al., The influence of saliva pH value on the retention and durability of bar-clip attachments, J Adv Prosthodont 2015;7:32-8

118. Magnetic retainers The introduction of rare earth alloys with high field strength and an intrinsic coercivity many times that of earlier alloys allowed the production of magnets that were not much larger than stud retainers The pioneering work of Gillings , at the University of Sydney, developed a split pole magnet assembly using cobalt samarium alloys. When paired with a magnetizable alloy keeper, this produced closed field magnetic retention The magnet was placed in the denture and the flat keeper on the abutment root, so that the path of the insertion of the denture was unaffected by the retainer 12/18/2019 118

119. The production of iron neodymium boron magnets in a laser-welded capsule solved the problem of corrosion Since magnetic retainers resist shear loads to a very small extent (10% of the normal retention force), only a small amount of lateral load can be transmitted by the actual retainer 12/18/2019 119

120. 12/18/2019 120 Jackson magnet

121. 12/18/2019 121 The Megafit 600 unit The Innovadent ( Gillings ) system

122. Hu F et al. (2019), conducted a study to evaluate the biomechanical behaviors of three different types of magnetic attachments, Flat-type, dometype and cushion-type, in two-implant-supported overdentures by three-dimensional finite element analysis methods. The biomechanical behaviors of peri -implant bone, abutment, and mucosa were recorded Flat-type magnetic attachment exhibited higher levels of maximum equivalent strain/stress in the peri -implant bone compared to dome-type and cushion-type attachments under vertical and oblique loading conditions 12/18/2019 122 Hu F et al., Comparison of Three Different Types of Two-Implant-Supported Magnetic Attachments on the Stress Distribution in Edentulous Mandible, Computational and Mathematical Methods in Medicine, Volume 2019

123. Oblique loading may play a detrimental role for all magnetic attachments in strain/stress distribution and denture stability Cushion-type and dome-type attachments are better choices in two-implant-retained mandibular overdentures , especially for patients with bad bone conditions such as osteoporosis or when a shorter or smaller diameter implant has to be used 12/18/2019 123 Hu F et al., Comparison of Three Different Types of Two-Implant-Supported Magnetic Attachments on the Stress Distribution in Edentulous Mandible, Computational and Mathematical Methods in Medicine, Volume 2019

124. Kim H. et al. (2012) conducted systematic review to address treatment outcome according to attachment systems for mandibular implant overdentures in terms of implant survival rate, prosthetic maintenance and complications, and patient satisfaction Four studies presented implant survival rates (95.8 - 97.5% for bar, 96.2 - 100% for ball, 91.7% for magnet) according to attachment system. Ten other studies presented an implant survival rate ranging from 93.3% to 100% without respect to the attachment groups. Common prosthetic maintenance and complications were replacement of an assay for magnet attachments, and activation of a matrix or clip for ball or bar attachments.. 12/18/2019 124 kim H. et al, Attachment systems for mandibular implant overdentures : a systematic review, J Adv Prosthodont 2012;4:197-203

125. Conflicting findings were found on the rate of prosthetic maintenance and complications comparing ball and bar attachments. Most studies showed no significant differences in patient satisfaction depending upon attachment systems The implant survival rate of mandibular overdentures seemed to be high regardless attachment systems. The prosthetic maintenance and complications may be influenced by attachment systems. However patient satisfaction may be independent of the attachment system. 12/18/2019 125 kim H. et al, Attachment systems for mandibular implant overdentures : a systematic review, J Adv Prosthodont 2012;4:197-203

126. Sato H et al. (2019), conducted a study to determine the appropriate attachment and design of a denture base for mandibular implant overdenture (IOD), the oral mucosa pressure caused by mandibular implant overdentures was measured using edentulous jaw models with various attachments Locator attachments (LA), ball attachments (BA), magnetic attachments (MA), and round-bar attachments (R-BA) were tested 12/18/2019 126 Sato H et al., Oral mucosa pressure caused by mandibular implant overdenture with different types of attachments, J Prosthodont Res (2019)

127. Under the bilateral load condition, the lower oral mucosa pressure value with BA was measured, compared to other attachments at all measurement sites. Under the unilateral load condition, the oral mucosa pressure value of BA was smaller than the other attachments at the measurement site on the loading side. BA has exerted the greatest effects on support and bracing, suggesting that, BA is suitable for reducing oral mucosa pressure during mastication 12/18/2019 127 Sato H et al., Oral mucosa pressure caused by mandibular implant overdenture with different types of attachments, J Prosthodont Res (2019)

128. Auxillary attachments Usually they are used with other attachments for improving retention. A variety of attachments fall into this category. They are screw and tube attachment, key and keyway/ interlocks, press o matic , Sectional dentures, bar connectors 12/18/2019 128 Kanathila H. et al., An insight into various attachments used in prosthodontics : A review, International Journal of Applied Dental Sciences, 2018; 4(4): 157-160

129. Screw units These devices are useful for securing and dismantling parts of a prosthesis in the mouth, when there is no common line of insertion of the whole They are particularly useful for joining the two components of a telescopic crown 12/18/2019 129 By incorporating precious metal threaded sleeve within the inner coping, the outer section can be retained with a screw

130. Friction devices Spring-loaded plungers are commonly employed to increase retention between the two sections of a telescopic prosthesis Split post can be used with sectional dentures 12/18/2019 130

131. Bolts Bolt units are used to connect the two parts of a sectional denture in the mouth Each part of the denture is inserted separately and the patient locks them together with the bolt 12/18/2019 131

132. Hinged flanges This type of device allows mucosal undercuts and interdental spaces to be used for retentive purposes 12/18/2019 132 A ‘Swing-lock’ prosthesis. The hinged labial flange allows proximal spaces to be used for retention

133. Attachment selection E.M. gauge: Matsuo developed a color -coded millimeter attachment gauge to define the vertical clearance available in the edentulous region of occluded casts for attachment selection Fabricated using Plastic and measures 75 mm. in length It is graduated from 3 to 8 mm. in one millimeter increments with a corresponding color code: Red designates 3 to 4 mm., Yellow designates 5 to 6 mm., Black designates 7 to 8 mm. 12/18/2019 133 Mensor MC. Classification and selection of attachments. J Prosthet Dent. 1973; 29:494-97

134. 12/18/2019 134 Mensor MC. Classification and selection of attachments. J Prosthet Dent. 1973; 29:494-97

135. E.M. attachment selector: Five 8 &1/2 by 11 inch color coded selector cards and a quick-reference overlay Each of the five cards is numbered to correspond with the five attachment classification groups It contains 30 points of information for each of more than 105 different attachment systems. The color code of the gauge corresponds exactly with that of the five selector cards. 12/18/2019 135 Mensor MC. Classification and selection of attachments. J Prosthet Dent. 1973; 29:494-97

136. 12/18/2019 136 Mensor MC. Classification and selection of attachments. J Prosthet Dent. 1973; 29:494-97

137. Use of the gauge and selector: The gauge is used to establish the height limitation. The proper attachments is first selected from the classification group; the overlay, which is a duplication of the slant-line information index, is used for the selection of an extracoronal attachment and the points of information are read directly from the compendium card. The keyed color -code measurements represent “Max.“-the size available commercially and “Min.‘‘-the amount an attachment may be reduced vertically and still maintain its manufactured characteristics. 12/18/2019 137 Mensor MC. Classification and selection of attachments. J Prosthet Dent. 1973; 29:494-97

138. Condition Indicated Contraindicated Distal extension Extracoronal attachments Steiger with axial rotation joint Intracoronal attachments Scott extracoronal attachment Tooth supported Steiger with roational joint Limited buccolingual space Extracoronal attachments Ceka attachments Intracoronal attachments Vertical space <4mm Miniature dalbo extracoronal attachment Ceka 700 series Ceka - mini retaining unit Intracoronal attachments Stabilex extracoronal attachment Ceka attachment 12/18/2019 138

139. Conclusion Precision attachments serve the function of retention, stress distribution and aesthetics successfully. Appropriate selection of attachments, plays a major role in the success of treatment. Proper maintenance and care by the patient and regular follow up decides on the long term success of the attachment and prosthesis. Use of precision attachment strengthens the aspects of retention and particularly, esthetics when compared to conventional removable partial dentures 12/18/2019 139

140. References GPT 9 Kanathila H. et al., An insight into various attachments used in prosthodontics : A review, International Journal of Applied Dental Sciences, 2018; 4(4): 157-160 Mensor MC. Classification and selection of attachments. J Prosthet Dent. 1973; 29:494-97 Preiskel H.W. Precision attachments in Prosthodontics: The applications of intracoronal and extracoronal attachments, volume 1, Quintessence books 12/18/2019 140

141. Zinner I.D. Precision attachments, Full-Mouth Reconstruction: Fixed Removable, Dental Clinics of North America, July 1987, Vol.31, No. 3, 395-415 Preiskel H.W. Precision attachments for partially dentate mouth, Annals of the Royal College of Surgeons of England (I974), vol 55, 294-298 Mohammad D.H. et al., The effects of two attachment types on the stresses introduced to the mandibular residual ridge, Quintessence Int, 2013, vol. 44 no. 8, 555-634 Petropoulus V.C., Mante F., Comparison of Retention and Strain Energies of Stud Attachments for Implant Overdentures , Journal of Prosthodontics 20 (2011) 286–293 by the American College of Prosthodontists 12/18/2019 141

142. Wang CH. et al., Connecting rigidities of various precision attachments compared with the conical crown retained telescope, Kaohsiung J Med Sci January 2005, Vol 21,No 1 kim H. et al, Attachment systems for mandibular implant overdentures : a systematic review, J Adv Prosthodont 2012;4:197-203 Caputo AP et al., Photoelastic analysis of stress patterns on teeth and bone with attachment retainers for removable partial dentures, J Prosthet Dent, 46:21, 1981 Aroso C et al., Effect of abutment angulation in the retention and durability of three overdenture attachment systems: An in vitro study, J Adv Prosthodont 2016;8:21-9 12/18/2019 142

143. Daas M. et al., complete finite element model of a mandibular implant-retained overdenture with two implants: Comparison between rigid and resilient attachment configurations, Medical Engineering & Physics 30 (2008 ) 2 18–225 Mahrous AI et al., Implant Supported Distal Extension over Denture Retained by Two Types of Attachments. A Comparative Radiographic Study by Cone Beam Computed Tomography, Journal of International Oral Health 2015; 7(5):5-10 Kim S et al., Comparison of changes in retentive force of three stud attachments for implant overdentures , J Adv Prosthodont 2015;7:303-11 12/18/2019 143

144. Prieskel HW. Overdenture made easy A guide to implant and root supported prosthesis, 1996, Quintessence Books Wang H et al., Effects of rigid and nonrigid extracoronal attachments on supporting tissues in extension base partial removable dental prostheses: A nonlinear finite element study, J Prosthet Dent 2011;105:338-346 Rivaldo EG et al., “In vitro” wear behavior of extracoronal precision attachments, Stomatos , Vol. 17, N.33, July/Dec. 2011 Silva AS et al., The influence of saliva pH value on the retention and durability of bar-clip attachments, J Adv Prosthodont 2015;7:32-8 12/18/2019 144

145. Sato H et al., Oral mucosa pressure caused by mandibular implant overdenture with different types of attachments, J Prosthodont Res (2019) Hu F et al., Comparison of Three Different Types of Two-Implant-Supported Magnetic Attachments on the Stress Distribution in Edentulous Mandible, Computational and Mathematical Methods in Medicine, Volume 2019 12/18/2019 145