Splinting in Periodontics

The seminar covers splinting in periodontics.
it explains the overall topic in depth.

1. SPLINTING IN PERIODONTICS 1

2. CONTENTS INTRODUCTION HISTORY DEFINITIONS AND TERMINOLOGIES CLINICAL RATIONAL FOR SPLINTING INDICATIONS & CONTRAINDICATIONS EFFECTS OF SPLINTING BASIC CONSIDERATIONS BEFORE SPLINTING TEMPORARY,PROVISIONAL & PERMANENT SPLINTS CONCLUSION REFERENCES 2

3. INTRODUCTION The ultimate goal in successful management of mobile teeth is to restore function and comfort by establishing a stable occlusion that promotes tooth retention and the maintenance of periodontal health. Some mobile teeth can be treated through occlusal equilibration alone (primary occlusal trauma) where as mobile teeth with a compromised periodontium can be stabilized with the aid of provisional and /or definitive splinting (secondary occlusal trauma) 3

4. Definitions : According to Glossary of Periodontic Terms 1986 : a splint is “an appliance designed to stabilize mobile teeth”. According to AAP (1996), a splint has been defined “as an apparatus, appliance, or device employed to prevent motion or displacement of fractured or removable parts.” The Glossary of Prosthodontic Terms defines splint as “ a rigid or flexible device that maintains in position a displaced or movable part; also used to keep in place & protect the injured part.” Dawson defines splinting as “the joining of two or more teeth for the purpose of stabilization”. 4

5. A splint is a device used to immobilize the teeth, and it is one of the oldest form of aids to periodontal therapy. A Splint is an appliance for immobilization or stabilization of injured & diseased parts. In dentistry, splinting is the joining together of two or more teeth to increase resistance to applied force through stabilization. A splint is an appliance that “joins two or more teeth in order to distribute & redirect functional and parafunctional forces so as to bring them within tolerance of the supporting tissues”. Splinting is defined as “…the joining of two or more teeth into a rigid unit by means of fixed or removable restorations or devices.” A splint is any appliance that joins two or more teeth to provide support. 5

6. TERMINOLOGY: STABILIZATION: Stabilization of a tooth is an increase in resistance to applied force by providing reciprocal antagonisms and increasing the effective root area. The force may remain the same, but the resistance is increased. TEMPORARY SPLINT: This is used on a short term basis, usually less than 6 months , and is often advocated to stabilize teeth during periodontal treatment. It may or may not 1ead to other types of splinting. PROVISIONAL SPLINT: This type of splint is used for a longer period of time from several months to as long as several years . It is used for diagnostic purposes. 6

7. PERMANENT SPLINTS: Permanent splinting of teeth that have been treated periodontally is also referred to as Periodontal prosthesis. Periodontal prosthesis may be defined as those restorative and prosthetic endeavors that are indicated and essential in the total treatment of advanced periodontal disease. 7

8. HISTORY Phoenician mandible from 500BC and another Phoenician prosthetic appliance was found from 400 BC in modern day Lebanon that is comprised of two carved ivory teeth attached to four natural teeth by gold wire. 8

9. Archeological excavations of the Etruscan society (8 th BC to the 1 st century AD) have found evidence of their use of wire ligation and gold bands to stabilize teeth. In early 1700s : Fauchard attempted tooth ligation. In the 1900s : several authors described splinting techniques that dated back to the 1800s. Hirschfeld (1950) was one of the first modern periodontal authors to advocate ligation of periodontally diseased teeth using either stainless steel wire or silk. His technique was extracoronal and involved only the anterior teeth. 9

10. WHEN TO SPLINT ? 10 AFTER PERIODONTAL THERAPY COHEN AND CHACKER HAVE NOTED… AFTER OCCLUSAL CORRECTION

11. Occlusal forces applied to a splints are shared by all teeth within the splint even if the force is applied to only one section of the splint. Rigidity of the splint acts as lever, so that the forces applied to some teeth in the splint may be much greater than before splinting. One tooth within the splint with occlusal disharmonies may cause damage to periodontium of the other teeth in the splint. 11 OCCLUSION NEEDED TO BE STABILIZED PRIOR TO SPLINTING ??????

12. INCREASED VERSUS INCREASING TOOTH MOBILITY Two clinical features should be analyzed to understand the full scope of the relationship between occlusal trauma and tooth mobility. The first is increased tooth mobility : Adaptation of the periodontium to occlusal forces that may not necessarily be considered pathologic. Mobile teeth with a complete and healthy connective tissue attachment and absence of inflammation can be maintained. Radiographic ( widened PDL space ) + clinically ( tooth mobility ) – manifestation to increased functional demnads . 12

13. Removal of the excess occlusal load through equilibration and perhaps, conventional splint therapy can decrease and, often at times, eliminate tooth mobility 13

14. Increasing tooth mobility : Clinical condition is due to occlusal trauma compromised by presence of inflammation and further destructive periodontal disease. Occlusal equilibration, periodontal therapy reevaluation for extraction or splinting of the affected teeth. 14

15. PRINCIPLES OF SPLINTING Main objective of splinting is to decrease movement three-dimensionally. Proper placement of a cross-arch splint. Unilateral splints that do not cross the midline tend to permit the affected teeth to rotate in a faciolingual direction about a mesio -distal linear axis. 15

16. INDICATIONS Moderate to advanced mobilities (2 degrees or more) are present and cannot be treated by any other means. Pre-prosthetic surgery; after orthodontic repositioning; surgical trauma Multiple teeth that have become mobile as a direct result of gradual alveolar bone loss, a reduced periodontium. Increased tooth mobility accompanied by pain or discomfort in the affected teeth. To avoid dislodging teeth prior to and during re-constructive procedures ( Occlusal reconstruction). 16

17. CONTRAINDICATIONS Moderate to severe tooth mobility in the presence of periodontal inflammation and / or primary occlusal trauma. Insufficient number of firm / sufficiently firm teeth to stabilize mobile teeth. Prior occlusal adjustment has not been done on teeth with occlusal trauma or occlusal interferences. 17

18. IDEAL REQUISITES OF SPLINTS Simple, Economic, Stable and efficient, Hygienic, Nonirritating, Not interfere with treatment, Esthetically acceptable, and Not provoke iatrogenic disease. 18

19. OBJECTIVES OF SPLINTING Rest Reduction of mobility Redirection of forces Redistribution of forces Restoration of functional stability To preserve arch integrity (proximal contacts) To stabilize mobile teeth during surgical, especially during regenerative periodontal therapy. To prevent migration and over eruption. Psychologic well being 19

20. Physiologic and pathologic tooth mobility : Usually assesses as amplitude of crown displacement resulting from application of a defined force (0.1N) 20 WHY TOOTH EXHIBITS MOBILITY

21. BIOLOGIC RATIONALE FOR SPLINTING In teeth with non-inflamed periodontal tissues, two basic factors determine the degree of tooth mobility: Persistent mobility after correction of underlying periodontal condition – PATHOLOGICAL MOBILITY If height of underlying periodontium reduced but no PDL widening, root mobility exempted by such teeth will be same as teeth with normal periodontium : PHYSIOLOGICAL MOBILITY 21 The height of the supporting tissues The width of the periodontal ligament.

22. TOOTH MOBILITY If a combination of a widened periodontal ligament and a reduced height of the periodontal support is the reason for the increased mobility, occlusal adjustment may be sufficient to reduce the mobility to an acceptable degree. However, if the patient’s subjective chewing comfort is still disturbed, splinting may be considered. OCCLUSAL ADJUSTMENT SPLINTING WIDENING OF PDL REDUCED HEIGHT OF SUPPORTING TISSUES 22

23. IN ADVANCED PERIODONTAL CONDITIONS : Progressive breakdown of periodontium not able to tolerate the normal masticatory forces. Periodontal therapy and occlusal adjustment of no value… SO WHAT CAN BE DONE ????????? 23 USE TEETH AS ABUTMENTS FOR CROSS ARCH DESIGN

24. S. Kourkouta , K. W. Hemmings L. Laurell . Restoration of periodontally compromised dentitions using cross-arch bridges. Principles of perio -prosthetic patient management BRITISH DENTAL JOURNAL VOLUME 203 NO. 4 AUG 25 2007 24

25. The only way to preserve such dentitions is to use teeth as abutments of cross arch design……and not unilateral fixed bridges. Cross arch design reduces lever effect of the occlusal forces and they are evenly distributed… Unilateral bridge concentrates the masticatory forces of normal magnitude onto the abutment teeth, worsening the underlying periodontal condition. 25

26. Splinting creates a multirooted unit, increasing the total area of root resistance. The centre of rotation of each tooth is so altered as to afford greater resistance to mesiodistal forces. Resistance to facio -lingual thrust results if the splint extends around the arch. If an abnormally mobile tooth is splinted to firm teeth, resistance of the loose tooth to coronal pressures in all directions is enhanced. 26

27. CLASSIFICATION OF SPLINTS On the basis of DURATION AND PURPOSE (LEMMERMAN in 1976) Temporary splints – less than 6 months during periodontal therapy Provisional splint – several months to years for diagnostic purpose Permanent splint – worn indefinitely REMOVABLE FIXED 27 Reversible mobility : normal peridontium Irreversible mobility : reduced periodontium

28. REMOVABLE Occlusal Splint with wire Hawley appliance with arch wire FIXED Intracoronal Amalgam Amalgam & Wire Amalgam , Wire & Resin Composite Resin & Wire Extracoronal Stainless steel wire with resins Wire & Resin with acid etching Enamel etching & composite resin Orthodontic soldered bands, Brackets & Wire Acrylic splints Metal band etc . Removable/Fixed Extra/Intracoronal Full/Partial veneer crowns soldered together. Inlay/Onlay soldered together. 28

29. Short Term , Provisional And Long Term….. (FERENZ in 1991) 29 SHORT TERM PROVISIONAL LONG TERM EXTRA CORONAL INTRACORONAL Fixed removable composite Wire with composite amalgam FIXED REMOVABLE BOTH

30. According to the type of material: Bonded composite resin splint; Braided wire splint; A – Splints. According to the location on the tooth: INTRACORONAL Composite resin with wire Inlays Onlays EXTRACORONAL Night Guard Tooth Bonded plastic and welded bands 30

31. According to Caranza , two major indications for periodontal splinting are a)to immobilize excessively mobile teeth so that the patient can chew more comfortably b)to stabilize teeth exhibiting increasing mobility. He further defined three procedures for provisional stabilization which are the reinforced resin splint for use in the posterior teeth the acid etch resin splint for use in anterior teeth the resin bonded metal splint. 31

32. Authors and their concepts on splintings Simring in 1952 : importance of direction of forces and the movement of teeth under occlusal loads. edentulous distance and the splinting effect. Simring stressed that splinting is indicated where the traumatic effects of occlusion are intense and the stimulating physiologic action of the occlusal forces needs to be improved. Morton Amsterdam and Lewis Fox in 1959 : defined that the term provisional splinting as the phase of restorative therapy utilizing a biomechanical combination of tooth dressing coverages and stabilization of teeth on an immediate and temporary basis.  Jens Waerhaug evaluate the justification for the splinting in periodontal therapy as a protective mechanism in the case of occlusal trauma. Lemmerman in 1976 splinting as to device as to reduced the mobility or stabilized an existing mobility. Ferenze in 1991 little rationale for splinting teeth manifesting primary occlusal trauma. 32

33. Simring in 1952 : Importance of direction of forces and the movement of teeth under occlusal loads and thus rationalized splinting as …... Edentulous distance and the splinting effect. Stressed that splinting is indicated where the traumatic effects of occlusion are intense and the stimulating physiologic action of the occlusal forces needs to be improved. Jens Waerhaug Evaluate the justification for the splinting in periodontal therapy as a protective mechanism in the case of occlusal trauma. They may indicate that splinting may speed up destruction of bone rather than retard it. Lemmerman in 1976 splinting as to device as to reduced the mobility or stabilized an existing mobility. Morton Amsterdam and Lewis Fox in 1959 Defined that the term provisional splinting as the phase of restorative therapy utilizing a biomechanical combination of tooth dressing coverages and stabilization of teeth on an immediate and temporary basis.  33

34. According to Caranza , two major indications for periodontal splinting are a)to immobilize excessively mobile teeth so that the patient can chew more comfortably and b)to stabilize teeth exhibiting increasing mobility. He further defined three procedures for provisional stabilization which are a) the reinforced resin splint for use in the posterior teeth, the acid etch resin splint for use in anterior teeth, and the resin bonded metal splint. As with any other appliance in the mouth, oral hygiene must be emphasized and must be taken into account in the design and construction of the splint. 34

35. According to the period of stabilization TEMPORARY STABILISATION Occlusal Splint with wire Hawley appliance with arch wire FIXED EXTRACORONAL Stainless steel wire with resins Wire & Resin with acid etching Enamel etching & composite resin Orthodontic soldered bands, Brackets & Wire INTRACORONAL Amalgam Amalgam & Wire Amalgam , Wire & Resin Composite Resin & Wire REMOVABLE 35

36. TEMPORARY SPLINTS 36

37. Most popular temporary extracoronal wire ligature and acrylic splint. Indicated for use around the mandibular anterior teeth and also around maxillary anterior teeth. Armamentarium The Wire Ligature-Acrylic Splint EXTRACORONAL TYPES 37

38. CLARK The Wire Ligature-Acrylic Splint J Periodotol 1969;40(6):371-379 38

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41. ORTHODONTIC BANDS Stabilize both anterior and posterior teeth proper attention to the contours of the bands and to check their relationship to the adjacent gingival tissue Teeth must be have open contcts so that a band or bands can be inserted. Acrylic may be placed over the bands for cosmetic purposes The multiple bands are welded together, it is necessary to have a common path of insertion 41

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43. RESIN-BONDED RETAINERS 43 cast from metals, usually non noble alloys that can be electrolytically or chemically etched greater inherent strength than a composite-resin splint created intraorally . Extra features such as grooves, pins and parallel preparations increase the retentive capacity of these splints

44. DiamondCrown ( Biodent Inc., Mont-Saint- Hilaire , QC) claim improved diametric tensile strength and bonding capabilities. These materials may be considered for use in extracoronal applications. No long-term clinical data are available for these materials; however, they seem promising at this time. 44

45. ACRYLIC BITE GUARDS ( NIGHT GUARDS) 45 most common type of appliance is one that covers the occlusal surfaces of the teeth usually covers the incisal & occlusal surfaces of maxillary teeth with occlusal stops for all the mandibular teeth on a flat surface area around centric relation & with sufficient cuspid rise to disocclude the posterior & anterior segments during lateral & protrusive excursions can be used only when there is an anterior overbite so that the palatal bite plane can disarticulate the posterior teeth.

46. Another appliance is Hawley's bite plane. Used as a retainer for maxillary teeth with tendencies toward pathological migration or relapse following orthodontic therapy. Often induces jiggling of such teeth. Biteplane - occlusal forces transmitted axially- eliminates jiggling forces 46

47. INTRACORONAL TYPES Wire ligation, Wire and acrylic, Amalgam with an embedded wire &/acrylic and Composite resin with or without embedded wire. INDICATIONS used only when permanent splinting is to follow. used on a provisional basis when tooth prognosis is guarded 47

48. 48 COMBINATION WIRE—COMPOSITE RESIN Klassman , Zucker Combination Wire—Composite Resin Intracoronal Splinting Rationale and Technique J. Periodontol . August, 1976

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50. Indications : Terminal periodontal involvement when the prognosis for the remaining abutments is not sufficient to warrant full or partial coverage cast restorations. Economic consideration Lower anteriors , where root proximity contraindicates the use of full cast coverage restorations. Aged or debilitated patients wrt time constraints Where prolonged temporary stabilization is needed with an eventual full coverage commitment. 50

51. ADVANTAGES Comparative ease of fabrication Cost Longevity Esthetic No subgingival margins Contours Physical properties and manipulation. DISADVANTAGES Potential pulpal initiation from acid occlusal wear Inability to control gingival third contours. Lack of control of root and recurrent caries. Inability to control root sensitivity Color primarily limited to anterior teeth. 51

52. Wire & Acrylic (A – splint) First popularized by Berliner Most commonly used in anterior teeth. 52 Becker, R.: Semi-Permanent Periodontal Splint: “A” splint. J. Michigan D.A., 46:306-309, 1964. Preparation of a channel approximately 3 mm wide and 2 mm deep in several teeth. Pulpal surfaces should be coated with a protectant. Platinized knurled wire 22 to 16 gauge (0.64 to 1.3 mm in diameter) is placed in the channel. Self-cure acrylic is placed to fix the wire in the channel. Occlusion is adjusted and the splint is polished .

53. The problem retention of the wire to the tooth the acrylic to the wire resultant acrylic and wire complex to the teeth. Berliner advocated the use of the widest wire necessary to almost fill the preparations. This wire had a tendency to lock into the undercuts of the preparations and acted to increase the retention of the acrylic. 53

54. Variation of the A splint by Kessler by placing threaded pins incorporated in the teeth along with wire and acrylic. Provides for primary stabilization when the wire is used alone and secondary stabilization with greatly increased retention when the acrylic is inserted to cover the wire. 54 The advantage of this variation of “A” splinting is that it greatly decreases the possibility of breakage and the need for frequent repair. Kessler Variation of the “A” Splint J Periodontal 1970

55. 55 Kessler Variation of the “A” Splint J Periodontal 1970

56. Amalgam Splint Its use is limited to the posterior teeth. Less strength than that of cast gold. Teeth are prepared in accordance with sound operative principles. Condense the amalgam in one unit. Two to five teeth may be splinted in this fashion. Amalgam splints tend to fracture easily. 56

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59. There are two possible disadvantages, to this form of stabilization The confinement of the procedure to only posterior teeth and The possibility of fracture (usually at the narrow part of the isthmus). 59

60. Wire, amalgam, and acrylic Trachtenberg (1976) combined the wire-and-amalgam and the wire-and-acrylic techniques. This approach allows one to insert individual compound amalgam restorations and finish their interproximal areas prior to insertion of the wire and acrylic. 60

61. STABILIZATION OF TEETH AFTER ORTHODONTIC TREATMENT After orthodontic treatment, teeth may require stabilization with either fixed or removable appliances. Allows continued minor movements for the final positioning of teeth. 61

62. 62 patient with a removable orthodontic retainer. Optimal positioning of teeth has been achieved by orthodontic movement; however, stabilization of teeth is required, and the unattractive spaces caused by undersized maxillary teeth need to be closed. A carefully planned appointment is required to accomplish the following: (1) remove any fixed orthodontic appliance, (2) add composite to close the diastemas , and (3) stabilize teeth with a twisted stainless steel wire and composite.

63. This unique splint allows some physiologic movement of teeth, yet it holds them in the correct position. The splint should remain in place for at least 6 months to ensure stabilization. Longer retention may be necessary, depending on the individual situation and recommendations of the orthodontist. 63

64. FIBER-REINFORCED COMPOSITE Fiber reinforced composite are structural materials with two different constituents Reinforcing component: strength & stiffness Surrounding matirx : reinforcement & workability. Fiber -reinforcement materials can be made from polyethylene yarns woven to create a ribbon, glass fibers woven to create a ribbon short and long strands of glass fibers embedded in a resin matrix ( preimpregnated glass fibers ). Unidirectional: long, parallel, continuous - Most Popular Braided & Woven. 64

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66. Glass fibers are treated with a silane chemical coupling agent to allow dental resins to chemically adhere to the glass fiber strands. To improve the bonding of resin to polyethylene fibers , these synthetic polyethylene fibers are chemically treated with thorough surface etching called plasma treatment, which allows the resin to chemically bond to the polyethylene fibers . Without this treatment, there would be no surface wetting of resin and bonding between the 2 substrates. 66

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69. Currently two categories of fiber reinforcement materials are used for intraoral use: PRE-IMPREGNATED NON PRE-IMPREGNATED 69

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71. Facial and incisal embrasures are defined with finishing burs to enhance esthetics . After finishing procedures, the rubber dam is removed, and the occlusion is evaluated. 71

72. PROVISIONAL SPLINTS Provide insight into whether or not stabilization of the teeth provides any benefit before any irreversible definitive treatment is even initiated. With this form of stabilization it is imperative that the patient goes on to a permanent restorative program. 72

73. Provisional splints can either be placed externally or internally. External splints typically are fabricated using Ligature wires, Nightguards , Interim fixed prostheses. Internal splints, on the other hand, are fabricated using Composite resin restorative material with or without wire or fiber inserts. 73

74. Adapted metal bands and acrylic Amsterdam and Fox have described the use of copper or gold bands fitted exactly to the subgingival termination of prepared teeth and then incorporated into self-curing acrylic. This technique fulfills all the objectives of a provisional restoration in that an exact marginal fit is achieved for caries-control and pulpal protection. Also, protective sub-gingival and supragingival coronal forms are more easily obtained, thus helping to achieve and maintain the health of the gingival tissue. Because of the added strength of the metal bands, frequent removal of the splints for various operative procedures (that is, impressions, coping transfers, assemblages) will not cause the splints to warp or the margins to become distorted. 74

75. Intracoronal methods are also available. Composite-resin restorations can be placed in adjoining teeth and cured to eliminate any interproximal separation. These restorations can be further reinforced with metal wires, glass-reinforced fibers or pins. If restoration of the mouth includes crowns, they can be splinted to each other by solder joints or precision attachments. 75

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77. NATURAL TOOTH PONTIC Indications Periodontally involved teeth warranting extraction Teeth having fractured roots Teeth unsuccessfully reimplanted after avulsion Root canal treatment been unsuccessful. As interim restorations until an extraction site heals if conditions require a conventional bridge or an implant. 77

78. Precautions The extracted tooth and abutments must be in reasonably good condition, especially the pontic , because it may become brittle and more susceptible to fracture The abutment teeth should be fairly stable The tooth to be replaced because a pontic must not participate in heavy centric or functional occlusion. If the adjacent teeth are mobile, it is frequently necessary to secure them by splinting with composite. 78

79. Pre operative Hope less prognosis w.r.to 31 31 was extracted under Local Anaesthesia Socket was curetted Remnants of PDL and necrotic cementum were removed Apical reduction done with air rotor Pontic design 79

80. Pulp extirpation done   Apex etched, bonded 42, 41, 32 etched, bonded Apex sealed with Flow Plus Composite 31 placed and splinted with INFIBRA 80

81. Immediate post operative 3 months post operative 81

82. Advantages: It is of the right size, shape and colour . Good aesthetic results Preservation of natural crown structure Reduced psychological impact on the patient Micro-resiliency of pontic allows stimulation of underlying tissue and avoids excessive post-extraction ridge resorption 82

83. PERMANENT SPLINTING Permanent splinting of teeth that have been treated periodontally is also referred to as Periodontal prosthesis. Periodontal prosthesis may be defined as those restorative and prosthetic endeavors that are indicated and essential in the total treatment of advanced periodontal disease. Permanent splinting is indicated whenever periodontal treatment does not reduce mobility to the point at which the teeth can function without added support. 83

84. Such devices serve to stabilize loose teeth, to redistribute occlusal forces, to reduce trauma and to aid in the repair of the periodontal tissues. Permanent splints are fabricated after periodontal treatment has been completed, when their use will extend the functional lifetime of the teeth. Also used for retention of teeth following orthodontic procedures and to prevent eruption of teeth without antagonists. 84

85. PERMANENT SPLINTS MAY BE CLASSIFIED AS FOLLOWS: 1. REMOVABLE - EXTERNAL A. Continuous clasp devices B. Swing - lock devices C. Overdenture (full or partial) 2. FIXED - INTERNAL A. Full coverage, three-fourths coverage crowns and inlays B. Posts in root canals C. Horizontal pin splints 3. CAST-METAL RESIN-BONDED FIXED PARTIAL DENTURES (MARYLAND SPLINTS) 85

86. 4. COMBINED A. Partial dentures and splinted abutments B. Removable / fixed splints C. Full or partial dentures on splinted roots D. Fixed bridges incorporated in partial dentures, seated on posts or copings 5. ENDODONTIC POSTS. 86

87. May be useful in situations in which fixed splinting is not possible or desirable. For eg . In advanced age, in poor physical or mental status, or when the prognosis is questionable, the dentist chooses to avoid full coverage. The cosmetic disadvantages of labial continuous clasping can be overcome by use of the swing –lock appliance, which tends to conceal the metal of the splint and avoid torque. REMOVABLE – EXTERNAL : SWING – LOCK DEVICES 87

88. OVERDENTURE When few teeth with questionable prognosis remain, an overdenture may be used. Advantage : More favorable crown-root ratio and retention of alveolar bone around roots. Proprioception Disadvantage : Long-term use has high incidence of recurrent periodontal disease. Patient must carry out adequate plaque control measures. 88

89. FIXED-INTERNAL Fixed permanent devices may incorporate a series of soldered castings such as crowns, three – quarter crowns, telescope crowns, inlays, horizontal pin splints. Splints are cemented in place. Full coverage is simple to perform otherwise inlays or pin ledges may be more conserving of tooth structure and simpler to use. It is important that these splints be rigid. Ideally the teeth and splint should be reciprocally stabilized in all directions ( i . e., mesial, distal, vestibules and apical). 89

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91. CAST-METAL RESIN BONDED FIXED PARTIAL DENTURE (MARYLAND SPLINTS) These are used with intact or very slightly altered enamel surfaces. This type of fixed prosthesis is functional, esthetic, reversible and economic. It consists of a metal frame bonded with resin to tooth enamel. Retention is enhanced by perforations or by slots. Although the original use was for anterior teeth, but can be designed for posterior teeth. The enamel bond is fairly strong, however excessively mobile teeth under a strong occlusal load can break loose from the metal framework. 91

92. Maryland bridge 92

93. Periodontal Prosthesis Miller T. Immediate and indirect woven polyethylene ribbon-reinforced periodontal-prosthetic splint: A case report Quintessence Int ¡995:26:267-271 93

94. SPLINTING IMPLANT RESTORATIONS Implant restorations have been splinted with fixed prostheses for reasons that differ from the indications used for splinting teeth. Whereas splinting provides stability to mobile teeth, implants are nonmobile . Therefore, when eccentric or excessive forces are applied on an implant, the implant is unable to move immediately away from the force. It does not pivot as a tooth; instead the forces are concentrated at the crest of the surrounding bone. 94