Precision attachment.pptx

Precision attachments play an important role in the field of prosthodontics. They help to improve the aesthetics while at the same time protecting the abutment teeth from debilitating stress.

1. PRECISION ATTACHMENTS Swapnaneel Pradhan

2. contents Definitions History Indications Contraindications Advantages Disadvantages Classification Selection of attachments Intra-coronal attachments Extra-coronal attachments Stud attachments Bar attachments Magnetic attachments Auxiliary attachments Referances 3/20/23 2

3. Definitions Attachment: a mechanical device for the fi xation, retention, and stabilization of a prosthesis a retainer consisting of a metal receptacle and a closely fi tting 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. Semiprecision attachment : a laboratory fabricated rigid metallic patrix of a fi xed or removable partial denture that fi ts into a matrix in a cast restoration, allowing some movement between the com- ponents; attachments with plastic components are often called semiprecision attachments even if prefabricated Precision attachment : a retainer consisting of a metal receptacle (matrix) and a closely fi tting 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 a removable partial denture; GPT - 9

4. synonyms Internal attachment, parallel attachment, frictional attachment, key and key way attachment, slotted attachment. 3/20/23 4

5. history Winder – ‘Winder’s design’: screw joint retention Parr (1886) – Extracoronal socket attachment Stair – Telescopic abutment restoration Hermes E S (1906) – T shaped precision attachment Ash (1912) – Split bar attachment system H shaped Chayes attachment (1912) 3/20/23 5

6. Indications Esthetics zone. Redistribution of forces required. Minimize trauma to soft tissue. Control of loading and rotational forces. Nonparallel abutments present. Segmenting of the long span bridges. Future salvages efforts. Improved retention. Movable joints in fixed movable bridge work. As stress breaker in free end saddles and bridges. Intracoronal attachments as effective direct retainers for removable partial dentures. As a connector for sectional dentures. Sections of a fixed prosthesis may be connected with intracoronal attachments. To lock a connector joining saddles in the opposite side of the arch. As contingency devices for the extension or conversion of existing dentures. Where fixed dentures are contraindicated due to periodontal condition. To retain hybrid dentures. Becerra G, Macentee M. A classification of precision attachments. J Prosthet Dent 1987;58:322‑7.

7. Contra-Indications Poor periodontal support Poor oral hygiene habits High caries index Inadequate space to employ attachment Compromised endodontics and restorative status Becerra G, Macentee M. A classification of precision attachments. J Prosthet Dent 1987;58:322‑7.

8. Advantages Improved esthetics and elevated psychological acceptance of the prosthesis better retention and stability, less liable to fracture than clasp, less bulk, and reduced incidence of secondary caries. Lateral forces in the abutment during the insertion and removal are eliminated, and more axial force during functions is achieved. Improved cross arch load transfer/force transmission and prosthesis stabilization incorporates broken stress philosophy that limits the potentially damaging forces (stress transfer) imparted to the abutment provide better vertical support and better stimulation to the underlying tissue through intermittent vertical massage. Patel H, Patel K, Thummer S, Patel RK. Use of precision attachment and cast partial denture for long‑span partially edentulous mouth‑A case report. Int J Appl Dent Sci 2014;1:22‑5.

9. Disadvantages Complexity of design, complex principles, and procedures for fabrication and clinical treatment. Expensive increased overall cost of the treatment. Requires high technical expertise for successful fabrication experience and knowledge on the part of dentist and laboratory technician are essential. Increased demand on oral hygiene performance. The tooth may have to be extensively prepared to provide required space to accommodate intra-coronal attachment. The attachment is subjected to wear as a result of friction between metal parts; as wear occurs, male portion fits more loosely, thus permitting excessive movement leading injury to abutment teeth. Patel H, Patel K, Thummer S, Patel RK. Use of precision attachment and cast partial denture for long‑span par‑ tially edentulous mouth‑A case report. Int J Appl Dent Sci 2014;1:22‑5.

10. Classification

11. Based on method of fabrication Precision attachment (prefabricated types): A precision attachment is fabricated from milled alloys. They are generally intra-coronal and non‑resilient. Their advantages include consistent quality, controlled wear, and easier repair. They have standard parts which are interchangeable. Semi precision attachment (laboratory‑made or custom‑made types): components usually originate as prefabricated or manufactured patterns (made of plastic, nylon, or wax) or hand waxed. Jumber JF. An Atlas of Overdentures and Attachments. Chicago: Quintessence Publication Co.; 1981. Crismani Dalbo Semi-precision

12. According to their relationship to the abutment teeth Intracoronal /internal attachment: If the attachment resides within the body/normal contours of the abutment teeth. Extracoronal /external attachment: If the attachment resides outside the normal clinical contours of the abutment crown/teeth. Radicular/ intraradicular stud type attachments: These attachments are connected to a root preparation. The female or male is soldered or cast to a root cap coping. Bar Type: Bar type attachments span an edentulous area and connect abutment teeth, roots, or implant. The removable bridge, partial denture, or overdenture fit over the bar and are connected to it with one or more retention sleeves, riders/ clips, or retentive plungers. Jumber JF. An Atlas of Overdentures and Attachments. Chicago: Quintessence Publication Co.; 1981. McCollum Zest Dalbo Rider Bar

13. Based on function or movement Solid/rigid: When metal‑to‑metal contact of the patrix matrix restricts the relative movement between the abutment and prosthesis during the functional loading (of the removable partial denture), the attachment is said to be rigid. Subclassified into a two types: Non‑lockable, and lockable Resilient: Abutment/tooth and tissue‑supported restorations are considered resilient. Many attachments are designed to permit movement of the denture base, and during functional loading, these attachments are considered to be resilient attachments. Functional movement of the prosthesis may be restricted to defined vertical, horizontal, and/or rotational path, or omnidirectional displacement of the prosthesis may be permitted Jumber JF. An Atlas of Overdentures and Attachments. Chicago: Quintessence Publication Co.; 1981. McCollum Dalbo stud

14. Based on modes of retention Frictional: Frictional retention is resistance to the relative motion of two or more surfaces in intimate contact with each other. Mechanical: Mechanical retention is resistance to the relative motion of two or more surfaces due to a physical undercut. Frictional and Mechanical: Frictional and mechanical retention combines both features of frictional and mechanical retention. Magnetic: Magnetic retention is the resistance to movement caused by a magnetic body that attracts certain materials by virtue of a surrounding field of force produced by the motion of its atomic electrons and the alignment of its atoms. Magnets do not provide lateral stability and are contraindicated for flat ridges. It is used in limited applications, heat curing will weaken magnets, and they are liable to corrode. Suction types: Suction is a force created by a vacuum that causes a solid object to adhere to a surface. An example would be a well‑fitting denture. Jumber JF. An Atlas of Overdentures and Attachments. Chicago: Quintessence Publication Co.; 1981.

15. Depending on the geometric configuration and design of the attachment system Key and keyway. Ball and socket. Bar and clip or bar and sleeve. Telescope. Hinge. Push button. Latch. Screw units. Interlock. Jumber JF. An Atlas of Overdentures and Attachments. Chicago: Quintessence Publication Co.; 1981.

16. Depending on purpose Attachments used for Removable dentures Attachments used for Fixed partial dentures Attachments used for Implant supported overdentures 3/20/23 16

17. MC Mensor (1973) Merrill C, Mensor JR. Classification and selection of attachments. J Prosthet Dent 1973;29:494‑7.

18. Selection of attachments Based on Location: Intra-coronal attachments, extra‑coronal attachments, and radicular/intra-radicular stud type attachments, bar type. Based on function: It is important to differentiate between a solid and resilient‑type restoration. Based on modes of Retention: They are frictional, mechanical, frictional and mechanical, magnetic and suction types. Space: The space available vertically, buccolingually, and mesiodistally plays a key role in attachment selection. Cost: Cost is directly related to the type and material of attachment selected.

19. In Selecting an Attachment System for a Removable Partial Denture intracoronal or extracoronal attachment? resilient or a non‑resilient type? The third consideration is that the largest attachment can be used within the given space should be chosen to gain maximum stability, retention, and strength for the prosthesis.

20. Intracoronal versus Extracoronal Attachment size and shape of the abutment teeth. Intracoronal attachment requires more teeth preparation and tooth reduction. Insufficient space  the abutment retainer will be over contoured on the proximal surface resulting in restoration that can create periodontal problems. Adequate space  intracoronal attachment is preferred as they direct the forces along the long axis of abutment teeth. Although extracoronal attachments are employed in areas of inadequate space, they can create areas which may be difficult to clean leading to mainte ‑ nance problems. The lever arm associated with extra‑ coronal attachment may not direct all force along the long axis of teeth.

21. Resilient Versus Non‑resilient Attachment Major differences of philosophy regarding the use of resilient or non‑resilient attachment system occur when dealing with distal extension edentulous situation. Theoretically, resilient attachment allows the func ‑ tional forces to be directed to the tissues and alveolar ridge, and the non‑resilient attachment primarily directs the vertical functional forces to the abutment teeth. Realistically, there is some sharing of function at loads in both systems.

22. Stress equalization Vertical displaceability of natural tooth ≠ soft tissue covering edentulous ridge. Thus forces applied to RPD are transferred to the abutments. Thus rigid connectors are damaging to the abutments. Stress directors are essential to protect them. Stress directors are adjusted to control the permitted vertical travel. 3/20/23 22 Stewart’s Clinical Removable Partial Prosthodontics; Ed. 4

23. Advantage: Minimal direct retential allowing the denture bases to operate more independently. Minimize tipping forces to the abutment teeth, thereby limiting bone resorption. Disadvantages: Fragile Costly Require constant maintenance Often difficult or impossible to repair. 3/20/23 23 Stewart’s Clinical Removable Partial Prosthodontics; Ed. 4

24. Stress breaking Many attachments allow certain degree of movement between the components. They are often known as ‘Stress-breakers’. Mensor called this term as misleading and called them as ‘stress distributor’ or ‘stress directors’. 3/20/23 24

25. Rationale: Movement should be restricted only to movable tissues Disadvantages: More complex, increased wear and breakage Increased bone resorption and trauma Fatigue of spring like device 3/20/23 25

26. EM attachment gauge, Matsuo in 1970 Developed a color‑coded millimeter gauge to define the vertical clearance available in the edentulous region of occluded casts for attachment selection. The gauge is made up of plastic and measures 75 mm in length. It is graduated from 3 to 8 mm in 1 mm increments with a corresponding color . Red → 3–4 mm. Yellow → 5–6 mm. Black → 7–8 mm.

27. E M Attachment selector consists of five by 11 inch color-coded selector cards and a quick-reference overlay. It is a compendium of the attachments and connecting units available throughout the world, and it contains 30 points of information for each of more than 105 different attachment systems. This is a total of over 3,000 points of information. Each of the five cards is numbered to correspond with the five attachment classification groups presented in the Table.   Merrill C, Mensor JR. Classification and selection of attachments. J Prosthet Dent 1973;29:494‑7.

28. Principles of Attachment selection forces should be widely distributed to all available tissues. The denture base of tooth/tissue‑supported removable partial dentures should be extended to cover the entire residual ridge within the limitation of functional muscle movements. The teeth and denture‑supporting area should both be used to provide support, bracing, retention, direct‑indirect retention, and stability. It is important that the removable partial denture framework can be properly related to the teeth and the denture base to the framework.

29. Intra-coronal Attachments

30. According to Mechanism of retentioin Prieskel Group I: Frictional With adjustment potential Without adjustment potential Preiskel Group II: Mechanical Precision attachments in Dentistry by Harold W. Preiskel

31. Depending on articular retention Precision attachments in Dentistry by Harold W. Preiskel

32. Passive attachment Matrix: simple channels closed at one end to provide stop Patrix : Solid slide Channels may be round or elliptical Omega Beyelar Precision attachments in Dentistry by Harold W. Preiskel

33. Active Attachment Active frictional grip attachment Eg. McCollum attachment (split patrix ) Active snap grip attachment Eg. Crismani Locked Precision attachment Attachments bolted by means of a liding bolt or latch Eg. Latch retained attachment

34. McCollum attachment Most robust H shapped attachment Single adjustment slot

35. Stern attachment Two adjustment slots

36. Crismani attachment Rigid/resilient Rigid crismani sttachment Frictional grip Mecanical – spring clip

37. Ney’s attachment Standard (conventional H shaped) Lock split (wide reinforcing plate) Latch retained

38. Baker’s attachment Male – skirt (unique feature)

39. Schatzmann attachment Dovetail shaped Spring loaded plunger

40. Extra-Coronal attachments

41. Rigid extra-coronal attachments Roach attachment (Ball and tube attachment) Oldest attachment Patrix – round ball Matrix - tube

42. Pin and tube attachment Patrix – round Matrix – tube

43. Stabilex attachment Two retention pins Disadvantage: increased length

44. Conex attachment Smaller version Two types of pins (friction and mechanical retention)

45. Resilient extra coronal attachments Dalbo attachment

46. Dalbo stress breaker attachment Allows rotational and vertical movement Excellent resistance to both distal and lateral displacing forces.

47. Ceka attachment Developed by Kurl Cluytens (1951) Matrix  metal ring retainer Patrix  Attachment pin (split metal post) Reduces frictional wear during insertion and removal

48. O-SO Ring or O-ring Patrix – post with the groove or undercut Matrix – O ring synthetic polymer gasket + encapsulator O-ring may be made up of: Silicone Nitrile Fluorocarbon Ethylene propylene

49. Stud attachments Its is the simplest of all attachments. It consists of two parts: The stud (male component): usually attached to a metal coping cemented over prepared abutment. Housing (female component) embedded in the fitting surface of the overdenture. Precision attachments in Dentistry by Harold W. Preiskel

50. Extra-radicular stud attachments Male element projects from the root surface The stud is attached to the metal coping cemented over the prepared abutment, while the housing is embedded in the fitting surface of the denture. Gerber Ceka Rothermann Precision attachments in Dentistry by Harold W. Preiskel

51. Intra-radicular stud attachment The stud is attached to the fitting surface of the denture and the housing is incorporated in the abutment. Zest Anchor Advantage Disadvantage Overcomes any space problem Leverage to the abutment tooth is reduced Attachment procedure is simple Due to flexibility of nylon, parallelism of the abutment teeth are no necessary. Susceptible to caries, as there is no coping Nylon stud may bend, causing difficulty of seating the denture. This may reqire frequent revisits for correction. Eating food without the overdenture may cause food lodgment in the female part. Precision attachments in Dentistry by Harold W. Preiskel

52. Guidelines for stud attachments Attachments should be aligned to each other Should be in line with the path of insertion of the denture Up to 10° divergence can be tolerated Contra indicated in significantly divergent roots or implants One stud on either side of the arch is sufficient. Simple copings may be placed on the other roots. Studs on adjacent roots are not advised due to difficulty in maintaining hygiene. Increasing the number of studs do not always increase retention, it may contribute to improved stability but will definitely weaken the denture base. Precision attachments in Dentistry by Harold W. Preiskel

53. Dalbo stud attachment Rigid unit Ball and socket unit (allows vertical and rotational movement)

54. Rotherman eccentric attachment Button shaped attachment Patrix – eccentric cylinder with undercut or groove Matrix – clip or clasp arm Advantage – occupies less space and easy to use Rigid units Resilient unit

55. Zest Anchor attachment Intra-radicular Patrix : polyethylene – nylon stud Matrix: intra-radicular funnel shaped tube

56. Gerber attachment Largest of the studs Resilient – spring controlled vertical unit Patrix – threaded post Matrix – retention spring and ring Disadvantages: Complex attachment system Requires more space Permits little rotation

57. Ceka attachment Patrix : attachment pin (split metal post) Matrix: metal ring

58. Schubiger Attachment Patrix – threaded post/screw Matrix – recessed collar, cap nut/lock nut Indication: divergent roots

59. Bar attachments It consists of a bar contoured to connect abutment teeth together, run parallel and overlie residual ridge. They are soldered to the copings and can be made of metal or plastic. Purpose of using bar attachments: Splinting of abutment teeth Retention and support to prosthetic appliance Spreads loading Precision attachments in Dentistry by Harold W. Preiskel

60. Advantages of bar attachments Rigidly splint the teeth Provides good retention, stability and support Provides cross-arch stabilization Positioned close to the alveolar bone and thus exhibits less leverage Precision attachments in Dentistry by Harold W. Preiskel

61. Disadvantages of bar attachments They increase torque. Plaque control is difficult Relining them is complicated. Higher bulk of the bur and related attachments Vertical and buccolingual space requirements limits their applications. They demand greater oral hygiene maintenance from the patient. Precision attachments in Dentistry by Harold W. Preiskel

62. Bar units They are rigid and there is no movement between bar and sleeve. They transmit occlusal stresses directly to the abutments. Thus they are tooth borne. Precision attachments in Dentistry by Harold W. Preiskel

63. Bar joints They are resilient in nature. Allow some rotational movement between bar and sleeve. Utilize support both from residual ridge and abutment. Thus both tooth and tissue borne. Precision attachments in Dentistry by Harold W. Preiskel

64. Important bar attachments Haden bar Dolber bar Baker clip Ackerman clip and CM clip King connector Precision attachments in Dentistry by Harold W. Preiskel

65. Dolder bar Egg shaped in cross-section Open sided sleeve Two sizes: 3.5mm x 1.6mm 3.0mm x 2.2mm Spacer allows some degree of vertical and rotationalmovement

66. Advantages: Excellent retention, stability and support Cross arch stabilization Disadvantages: Increased bulk Plaque accumulation Soldering necessary Wearing

67. Hader bar Helmut Hader in 1960 Available as prefabricated plastic pattern Resin/plastic sleeve with no spacer More support and retention Reduced movement/resiliency Soldering not required

68. Ackerman bar Circular cross section and can be bent in all planes

69. CM Rider bar Made of precious or semi-precious alloy Retention tags in the long axis of the bar Sleeves Disadvantage: occupies more buccolingual space

70. Magnetic attachment Detachable keeper element Generally made of stainless steel and is fixed to abutment teeth by cementing or screwing. Denture retention element Has paired, cylindrical SmCo magnets axially magnetized and arranged with their opposite poles adjacent. Precision attachments in Dentistry by Harold W. Preiskel

71. Advantages: Smaller size and strong attractive force Constant retention Easy to incorporate in prosthesis Automatic seating Very useful for disabled or senile patients Less lateral force to abutment teeth 3/20/23 71

72. Disadvantages: Loss of retention due to corrosion and heat instability Requires encapsulation within inert alloys Impossible to repair High cost Less longevity Sliding movements on their keepers 3/20/23 72

73. AUXILLARY ATTACHMENTS Screw and tube attachments Key and key-way attachments Pressomatic attachments Bar connectors Attachments for sectional dentures 3/20/23 73

74. Attachment for sectional dentures Two-part dentures One part – chrome cobalt base Second part – removable acrylic flange with teeth Advantage: superior esthetics with improved retention 3/20/23 74

75. Thank you 3/20/23 75

76. references Stewart’s Clinical Removable Partial Prosthodontics; Ed. 4 Precision attachments in Dentistry by Harold W. Preiskel Becerra G, Macentee M. A classification of precision attachments. J Prosthet Dent Patel H, Patel K, Thummer S, Patel RK. Use of precision attachment and cast partial denture for long‑span partially edentulous mouth‑A case report. Int J Appl Dent Sci 2014;1:22‑5. Jumber JF. An Atlas of Overdentures and Attachments. Chicago: Quintessence Publication Co.; 1981. Merrill C, Mensor JR. Classification and selection of attachments. J Prosthet Dent 1973;29:494‑7 3/20/23 76