Precision and Semi- Precision Attachments Where? When? Why? George E. Bambara, MS, DMD FACD, FICD

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1 Precision and Semi- Precision Attachments Where? When? Why? George E. Bambara, MS, DMD FACD, FICD

2 Objectives of the Program Understanding how attachments preserve hard and soft tissue Selection of the appropriate attachments Understand the uses of attachments Familarization with different attachments Maintenance and hygiene

3 Properly Designed Clasps Work?????? Concerns?????? Uneven distribution of forces Possible orthodontic movement Periodontal compression

4 Removable Partial Dentures Periodontal Status RPD s WERE ASSOCIATED WITH Increased periodontal pathology Increased plaque and tarter accumulation Increased gingival inflammation Increased probing depths Increased recession Increased abutment tooth mobility Zlataric et.al., The Effect of Removable Partial Dentures on Periodontal Health of Abutment and Non-Abutment Teeth. JPeriodontology, 2002, 73:

5 Clasps vs. Attachments CLASPS: Less expensive. 5 to 6 year life. 30% loss of retention. Poor chewing efficiency. 93% caries rate. 50% compliance. ATTACHMENTS: 15 year + life. More expensive. 99% retention. Excellent chewing efficiency. 8% caries rate. 100% compliance. Rantanen, Wetherall and Smales, Feinberg et.al.

6 CLASS I LEVER

7 Class II Lever

8 CLASS III LEVER Class III Lever

9 Indications for Attachments Aesthetics Redistribution of forces Minimize trauma to soft tissue Control of loading and rotational forces Non parallel abutments- Segmenting Future salvage efforts- Segmenting Retention

10 Functional Classifications Class 1A- Solid, rigid, non-resilient Class 1B- Solid, rigid- lockable Class 2- Vertical resilient Class 3- Hinge resilient Class 4- Vertical and hinge resilient Class 5- Rotational and vertical resilient Class 6- Universal, omni-planer

11 Patient Dexterity and Attachment Wear Insertion and removal cause wear Poor dexterity Avoid multiple attachments with complex a complex path of insertion Use lingual guiding arms

12 What is a Precision Attachment? An attachment that is fabricated from milled alloys Tolerances are within.01mm

13 Precision Attachments They are Generally Intracoronal Rigid = NonResilient

14 Benefits of Precision Attachments Consistent quality Controlled wear Less wear Easier repair Standard parts are interchangeable

15 What is a Semi-Precision Attachment? An attachment that is fabricated by the direct casting of plastic, wax, metal, or refractory patterns Their method of fabrication subjects them to inconsistencies

16 Benefits of Semi-Precision Attachments Less costly Easy fabrication May be cast in alloy

17 Semi-Precision Attachments They Are Generally Extracoronal Non-rigid = Resilient

18 Resilient Attachments 0.1mm 0.4 mm difference in the displacement of the tissue and the denture base, as opposed to the axial intrusion of the abutment teeth Directs forces to the supporting tissues and the abutment teeth

19 Selection of Attachments Location Opposing arch Function Retention Available space ( 3-5mm ) Cost

20 Criteria Selection for Resilient and Non Resilient Attachments Do not oppose two resilient attachments unless teeth are very weak Opposing distal extensions with strong abutments: upper - non resilient, lower - resilient Lower distal extension vs. Natural dentition - resilient Full denture - non resilient

21 Coronal Attachments INTRACORONAL: EXTRACORONAL Placed within the contours of the crown form Needs more tooth reduction Rigid connectors Placed outside the contours of the crown form Needs less tooth reduction Stress redirectors and are considered resilient

22 Stud Attachments A ball and socket type of attachment in which one component is attached to an abutment or implant, and the other element is retained in the prosthesis

23 Advantages Stud Attachments Low profile Easy hygiene maintenance Enhanced crown/root ratio

24 Dalla Bona The Ball Attachment A spherical, resilient, adjustable stud attachment with vertical and rotational movement for retaining partial and complete overdentures

25 Advantages Low Profile - limited space Easy path of insertion Adjustable female All adjustments done in prostheses Can be rigid vertical movement only Can be resilient vertical and rotational Easy fabrication Hygienically maintainable

26 Accessory Attachments Plunger Screw Type Frictional

27 Magnetic Attachments Processing magnet- in denture Intraradicular keeper All magnetic attachments should be processed chairside in the denture

28 Magnetic Indications Overdentures Implant restorations

29 Magnetic Realities Provide little lateral stability Used in limited applications Heat curing will weaken magnets Corrosion

30 Attachment Selection Overdentures- Ridge evaluation and esthetics Fixed- Ridge evaluation, gingival esthetics Number of implants Anterior-Posterior spread Opposing arch?? Function Fixed- Rigid, screw retained Overdenture- Load bearing or nonload bearing Retention Available space Cost

31 Patient Considerations Parallel attachments for easier path of insertion Less attachments better Patient dexterity Hygiene Stannous Fluoride rinses 3 month recall

32 Anterior/Posterior Spread A line from the center of the most anterior implant to a line joining the distal aspects of the two most distal implants Indicates the amount of cantilever that can be reasonably placed Usually, 2.5 times the A/P spread

33 A/P Spread Actual Length of Cantilever Depends on: Stress factors Parafunctional Habits Crown heights Implant width Number of implants Opposing teeth or denture

34 Controlling Stress Stress=Force/Area Force Stress Area

35 Torque= Force x Perpendicular distance from the line of force to the center of rotation

36

37 Cuspal Inclination

38 Cuspal Inclination

39 Treatment Plan Options Fixed Removable Implant Supported Soft Tissue Supported Implant Retained

40 Treatment Plan Option 1 Lower Edentulous Fixed 5-6 Implants

41 Prosthetic Options-Lower 5-6 Implants Hybrid Denture Fixed Crown and Bridge Cantilever 10-15mm

42 6 Implants-Fixed Implant Supported X X X X

43 5 Implants- Fixed Implant Supported X X A B C D E X X

44 Treatment Plan Option 2 Lower Edentulous Removable 5 Implants

45 Prosthetic Options- Removable Overdenture-Implant Supported Gold Bar w/ O Rings Distalized O Rings Cantilever 10-20mm Gold Bar with Hader Clips Distalized ERA S Cantilever 10-20mm B C D B C D A E A E

46 Treatment Plan Option 3 Lower Edentulous Removable 4 Implants

47 Prosthetic Options- Removable Implant and Tissue Supported Gold Bar with O Rings Cantilever 5-10mm Gold Bar with Hader Clips and ERA S Cantilever 5-10mm a b c d a b c d

48 Treatment Plan Option 4 Lower Edentulous Removable 3 Implants

49 Prosthetic Options- Removable Overdenture-Lower Implant and Tissue Supported Gold Bar w/ 2- O Rings- Overdenture No Cantilevers

50 3 Implants- Removable Overdenture Implant and Tissue Supported B C D

51 Treatment Plan Option 5 Lower Edentulous Removable 2 Implants

52 Prosthetic Options Removable Overdenture-Lower Tissue Supported Gold Bar w/ Hader Clip O Ring on each implant ERA attachment on each implant

53 2 Implants-Removable Tissue Supported B D

54 Treatment Plans Upper Edentulous Four Options

55 Treatment Plan Option 1 Upper Edentulous Fixed 8 Implants

56 Prosthetic Options Fixed- Upper Implant Supported Fixed Crown and Bridge Hybrid Denture No Cantilevers Necessary

57 8 Implants- Fixed Implant Supported 7 X X X X

58 Treatment Plan Option 2 Upper Edentulous Removable 8 Implants

59 Prosthetic Options- 8 Implants Removable- Upper Implant Supported Gold Bar w/ O Rings- Overdenture Gold Bar w/ 3 Hader Clips Overdenture- No Palate Cantilevers-Optional

60 8 Implants- Removable Implant Supported Gold Bar Overdenture w/ O Rings Gold Bar Overdenture w/ Hader Bar / Clips Palate No Palate

61 Treatment Plan Option 3 Upper Edentulous Removable 6 Implants

62 Prosthetic Options Removable- Upper Implant Supported Gold Bar w/ 4- O Rings and distal to #s 4 and 13 Gold Bar w/ Hader Clip- ERAS distal on #4 and 13- Overdenture-No Palate Cantilever 5-10mm

63 6 Implants- Removable Implant Supported Gold Bar w/ O Rings 5-10mm Cantilever Gold Bar w/ Hader clips and ERA s 5-10mm Cantilever

64 Treatment Plan Option 4 Upper Edentulous Removable 4 Implants

65 Prosthetic Options Removable- Upper Tissue Supported Gold Bar w/4 O Rings- Overdenture w/ No Palate Gold Bar w/ Hader Clip and 2 distalized ERA attachments w/ Overdenture- No Palate No Cantilever

66 Arch Form 4 Implants-Tissue Supported Square Arch Tapered Arch Maximum contact with tissue No contact with Bar Attachments are for retention ONLY

67 Treatment Planning Design sensibility and flexibility in the treatment plan Design and implant concepts will vary Plan ahead for success Have a disaster plan In most cases, less attachments are better

68 What Is an Overdenture A complete denture that is supported and often retained by the underlying teeth or implants and tissue

69 Abutment teeth or implants may or may not be connected to the denture via attachments

70 Studs Bars Copings Load bearing Magnets Implants Overdenture Attachments Extraradicular Teeth Combinations Non-Load-bearing Posts Intraradicular?????????????????????????????????

71 Overdenture Attachments Radicular: Extraradicular Studs, magnets, ERA Intraradicular Zaag, Zest, Sterns anchor root Bars: Bar joints Bar units Round Ovoid Square Rectangular

72 Objectives of the Program Understand how overdentures preserve hard and soft tissue Maintain proprioception Understand the function of overdenture attachments and simplify attachment selection Increasing crown/root ratios to preserve abutments Hygiene maintenance

73 Carlson and Persson, Odontologist Revy, Sweeden 1967 Anterior mandible average bone loss first year after extractions was 4mm Tallgren, JPD,1972 Bone loss continues for at least 25 years

74 Dentures vs Overdentures Natural dentition 90% Chewing Efficiency Complete dentures 59% Overdentures 79% Rissin and House, JPD, 1978

75 Indications for Overdentures Periodontal disease Few remaining teeth Insufficient crown/root ratios Vertical space Favorable path of insertion Retention

76 Advantages of Overdentures Maintenance of bone height around teeth by preserving roots Attenuates resorption patterns of alveolar ridges Gentler to the tissues Increases crown/root ratios Psychological security Enhanced speaking ability Maintains Proprioception

77 Disadvantages of Overdentures Esthetic Considerations Bulkiness Root canal therapy Increase space requirements: -interarch -interocclusal Increase costs

78 Crown / Root Ratios

79 Attachment Retained Overdentures All the advantages of Overdentures PLUS Superior aesthetics Stability and comfort Increases proprioception Rigidity or resiliency Mechanical retention Support Increased psychological security and patient acceptance

80 Overdentures Attachment Considerations Load Bearing Solid / Rigid Transfers stress towards the retained roots or implants and away from the ridge No vertical resiliency, some hinge or rotational resiliency Shares the load of occlusion with the mucosal surface Magnets, Flexi ball, Dalbo Rotex, Bars

81 Overdentures Attachment Considerations Non- Load Bearing Resilient Transfers stress away from the retained roots or implants and towards the tissue Vertical resiliency Selected frequently Dalla Bona, Rotherman, Ceka, Uni Anchor, OSO, ORS, ERA, Bars

82 Overdenture Evaluation Partial Denture Present Tooth position Occlusion Mount casts to vertical dimension No Partial Denture Mount cast to vertical dimension Diagnostic denture wax up reestablish occlusion Silicone matrix for space evaluation

83 Direct Placement Male or female premanufactured attachment is cemented into root Denture is made and inserted Corresponding male or female attachment is inserted in root Attachment is picked up directly in the overdenture with cold cure acrylic Placed by Dentist

84 Indirect Placement Male or female attachment is cemented into root or may need to be cast onto coping Corresponding male or female transfer analog is inserted into root attachment Transfer impression is taken and models are poured with transfer in place Laboratory processes denture with corresponding attachment in place Placed by Laboratory

85 Proceedures To Follow 5 mm or more root remaining in bone Stable perio Mount study models evaluate space required Select OD attachment obtain reference manuals Begin denture proceedings Root canal therapy Decoronate roots, extractions, insert temporary denture reline allow time for healing Prep tooth for attachment and cement attachment Insert denture, make adjustments, post placement reline Pick up male attachment in denture

86 Hader Spark Erosion Round Andrews Dolder Ovoid Bar Designs Branson Double Bar Rectangular Custom Milled Square

87 Attachments and Bars Intra Bar Extra Bar Circum Bar

88 Extra Bar Attachment placed on the superior aspect of the bar Increases strength of bar Requires more interarch space

89 Intra-Bar Connection between the two components directs the forces of mastication closer to the crest of the ridge Decreases lever arm mechanics on the supporting teeth Bar strength may be compromised

90 Circum-Bar Attachment wraps itself around the bar Allows for rotation around bar

91 The Milled Bar Main Advantage Final prosthesis is extremely stable because lateral forces are best managed by an intimately fitting primary and secondary bar This minimizes stress on the attachments

92 The Bar Overdenture Advantages Increased stability and retention than an attachment retained overdenture Accomodates a wide variety of implant angulations Bar splints implants together Provides better resistance to lateral forces when in function Pose less of a chance of failure at bone-implant interface

93 The Bar Overdenture Disadvantages More costly More technique sensitive