Restoration Of Endodontically Treated Tooth PDF

Restoration Of Endodontically Treated Tooth By Dr. Mohammed Hosny Professor of Fixed Prosthodontics Collage of Dentistry Taibah University 4/8/2023 M.Hosny 3 Causes of Weakness For endodontically treated tooth Caries, endodontic treatment, and the placement of previous restorations. Criter...

Restoration Of Endodontically Treated Tooth By Dr. Mohammed Hosny Professor of Fixed Prosthodontics Collage of Dentistry Taibah University 4/8/2023 M.Hosny 3 Causes of Weakness For endodontically treated tooth Caries, endodontic treatment, and the placement of previous restorations. Criteria of successful RCT 1- Good apical seal 2- No sensitivity to pressure 3- No exudate 4- No fistula 5- No active inflammation 4/8/2023 M.Hosny 4 RESTORATIVE TREATMENT PLANNING OF NON - VITAL TEETH  Restorative treatment decisions depend on the following:  Amount of the remaining tooth structure.  Functional demands that will be placed on the tooth.  Need for the tooth as an abutment in a larger restoration.  Teeth with minimal remaining tooth structure face the following challenges:  They have an increased risk for fracture.  They provide decreased retention for the restoration.  They are affecting the periodontal attachment. 4/8/2023 M.Hosny 5 Considerations For Anterior Teeth Not always require complete coverage with a crown. Conservative RCT preparation composite restoration is enough Conservative RCT preparation with discoloration bleaching Destructive RCT preparation full coverage crown 4/8/2023 M.Hosny 6 Considerations For Posterior Teeth Subject to greater loading cusps can be wedged apart. Complete coverage is recommended on teeth with a high risk of fracture. A cast post & core when there is significant coronal tooth loss. 4/8/2023 M.Hosny 7 Post OR Not According to Peroz Classification (2005)  Class I: Class II: Class III: Class IV: Class V:- 4/8/2023 4 Walls present ……. (B + L + M + D) 3 Walls present …….. B + L + { M or D } 2 Walls present ………. B + L one Walls present …….. B or L No walls M.Hosny 8  According to Peroz, if class I, II, and III cavity walls after preparation have thicknesses greater than 1.0 mm and axial heights of at least 2.0 mm a post is NOT recommended.  Classes IV&V with axial heights (Ferrule) of at least 2.0 mm a post is recommended. 4/8/2023 M.Hosny 9 4/8/2023 M.Hosny 10 Post crown (Dowel crown) It is a full coverage crown that gains its retention by a post (dowel) inserted in the prepared root canal. 4/8/2023 M.Hosny 11 Requirements Of The Dowel  Provide maximal retentiveness to the core.  Physical properties compatible to dentin.  Maximum retention with minimal removal of dentin.  Even distribution of functional stresses along the root surface.  Esthetic compatibility with the definitive restoration and surrounding tissue.  Biocompatibility of the material (non-toxic or allergic reactions). 4/8/2023 M.Hosny 12 Requirements Of The Dowel  Minimal stress during placement and cementation.  Resistance to displacement.  Easy for retrievability.  Material compatibility with core.  Ease of use, safety.  Reasonable cost. 4/8/2023 M.Hosny 13 Components of the dowel crown system A. Dowel C B. Core: metallic or non-metallic B C. Extra-coronal restoration: A metallic, non-metallic, or combination 4/8/2023 M.Hosny 14 Indications of dowel crown 4/8/2023 M.Hosny 15 Individual restoration for badly mutilated endodontically treated anterior and posterior teeth 4/8/2023 M.Hosny 16 Retainer for short span bridge (replacing only one missing tooth), when the abutment is endodontically treated. 4/8/2023 M.Hosny 17 Extensive bilateral proximal caries with pulp exposure. Fractured teeth with pulp exposure. 4/8/2023 M.Hosny 18  Endodontically treated teeth with biologically sound long, thick and strong root.  Endodontically treated teeth with perfect apical and lateral root canal filling. 4/8/2023 M.Hosny 19  Endodontically treated teeth without any periapical pathosis.  Endodontically treated teeth with healthy periodontal and alveolar support. 4/8/2023 M.Hosny 20 Contra-indications of dowel crown 4/8/2023 M.Hosny 21 1. Improper root canal filling 2. Presence of peri-apical pathosis 4/8/2023 M.Hosny 22 3. Patient with diseased periodontal support 4. Weak, thin, curved and very narrow root 5. Retainer for long span bridge 6. In case of cantilever bridge 4/8/2023 M.Hosny 23 Liability to use a root after complete loss of coronal portion Provide good retention Advantages Correction of mal-aligned tooth High esthetics can be achieved 4/8/2023 M.Hosny 24 Disadvantages  Limited to non-vital teeth  Placing the post requires an additional operative procedure.  Preparing a tooth to accommodate the post entails removal of additional tooth structure.  Root fracture may occur due to improper canal preparation or improper post selection.  The post can complicate or preclude future endodontic re- treatment that may be necessary. 4/8/2023 M.Hosny 25 Classification of the dowel and core systems According to:1. Material 2. Retention 3. Attachment 4. Method of construction 4/8/2023 M.Hosny 26 All metallic 1. According All non-metallic to the material Combination 4/8/2023 M.Hosny 27 All-metallic 4/8/2023 M.Hosny 28 Non-metallic Ceramic 4/8/2023 Fiber reinforced composite M.Hosny Woven-fiber composite 29 Fiber post (dowel) Carbon fiber Glass fiber Quartz fiber 4/8/2023 M.Hosny 30 Carbon fiber dowel Glass fiber dowel 4/8/2023 M.Hosny 31 Ceramic Glass-ceramic 4/8/2023 Alumina-oxide M.Hosny Zirconia 32 Ceramic dowels 4/8/2023 M.Hosny 33 • Metallic dowel and the core is Combination made (either with composite or reinforced glass ionomer) M.Hosny 4/8/2023 34 2. According to retention Retained by: Dowel only  Dowel and pin  Dowel and collar 4/8/2023 M.Hosny 35 Retained by dowel and collar The root face is beveled on buccal and lingual surfaces and shoulder finish line is prepared at the end of the bevel. 4/8/2023 M.Hosny 36 3. According to attachment Attached:  Dowel, core & crown are constructed as one piece Detached:  Two-piece restoration  Three-piece restoration 4/8/2023 M.Hosny 37 4/8/2023 M.Hosny 38 4. According to method of construction Custom-made dowel 4/8/2023 Prefabricated dowel M.Hosny 39 Custom-made dowel Made from Advantages 4/8/2023 • Nickel-chromium • Type IV gold alloy • All-ceramic Cobalt-chromium Titanium alloy • Very strong • Better fit M.Hosny 40 Extremely tapered When to use canals custom made dowel Non-circular canals Loss of more than 50% of coronal tooth structure 4/8/2023 M.Hosny 41 4/8/2023 M.Hosny 42 Different sizes, shapes and designs are available with its special drills Does not resist rotation Prefabricated dowel The coronal part contain mechanical interlock Main advantage is the simplicity of the technique 4/8/2023 M.Hosny 43 Tapered dowels 4/8/2023 Parallel-sided dowels M.Hosny 44 River Nile at Luxor Egypt 4/8/2023 M.Hosny 45 Conservatism Principles of tooth preparation Retention form Resistance form 4/8/2023 M.Hosny 46 1. Conservatism a. Radicular preparation  Minimal root canal enlargement.  Over enlargement can weaken the root. b. Coronal preparation  Maintain the coronal tooth structure as much as possible.  Only caries and undermined enamel should be removed. 4/8/2023 M.Hosny 47 Preparation geometry Dowel design 2. Retention form Dowel length Dowel diameter Luting agent 4/8/2023 M.Hosny 48 Retention form Preparation geometry 4/8/2023 M.Hosny 49 Retention form Dowel design Smooth (least retentive) (A) Serrated (more retentive) (B&E) Threaded (best retentive) (C&D) 4/8/2023 M.Hosny 50 Retention form Dowel length Length of the post should be  Leave 4-5 mm root canal filling intact.  2/3 of the root length.  At least equal to the coronal part (1:1).  7 mm at posterior teeth & 9mm for anterior teeth from CEJ. 4/8/2023 M.Hosny 51 Retention form The longer post, the better distribution of stresses, resulting in reduced stress at the apical end of the post because of leverage. Extending the length to two-thirds of the root length results in a superior fracture resistance compared with short posts. 4/8/2023 M.Hosny 52 Retention form Dowel diameter  The greater diameter, the greater retention. That explains why cylindrical posts are more retentive than conical posts.  A good general rule to follow is to avoid enlarging the post space. One or two endodontic file sizes beyond the largest size required for endodontic treatment.  Dowel diameter should not exceed 1/3 of root diameter. 1.0 mm 4/8/2023 1.0 mm 1/3 1/3 1/3 M.Hosny 53 Retention form The choice of the luting agent has little effect on dowel retention Luting agents The type of the dowel material plays an important role in luting agent selection 4/8/2023 M.Hosny 54 Principles of tooth preparation 3. Resistance form Stress distribution Rotational resistance Ferrule effect 4/8/2023 M.Hosny 55 Resistance form 1. Stress distribution During the function, the greatest stress concentration is in cervical and apical areas 4/8/2023 M.Hosny 56 Greater length allows for more even stress distribution and better retention 4/8/2023 M.Hosny 57 As dowel length increases, stresses decrease 4/8/2023 M.Hosny 58 Parallel-sided dowel distribute forces more than the tapered dowel 4/8/2023 M.Hosny 59 Fractured Post and Crown Fractured Post and Crown Vector of Force Vector of Force Fractured root Fractured root Vector of Force Vector of Force 4/8/2023 M.Hosny 60 We can use parallel-sided dowel with tapered apical end 4/8/2023 M.Hosny 61 Threaded dowel induces great stresses during its screwing. Flexi dowel is a parallel-sided dowel with split shank 4/8/2023 M.Hosny 62 Resistance form 2. Rotational resistance  To prevent rotation of the dowel with circular cross-section  When massive coronal tooth structure is lost 4/8/2023 M.Hosny 63 Resistance form 3. Ferrule Definition: 360° circumferential vertical axial dentin coronal to finishing line, It should be 1.5-2 mm height as a minimum. 1.5 -2.0 mm vertical tooth structure 4/8/2023 M.Hosny 64 Ferrule effect Purpose: To improve the structural integrity of the pulpless tooth by Protects the post against fracture Minimizes post dislodgement Protects the cement seal at the margin of the crown Against lateral force during dowel insertion 4/8/2023 M.Hosny 65 4/8/2023 M.Hosny 66 4/8/2023 M.Hosny 67 4/8/2023 M.Hosny 68 Removal of endodontic filling material Procedures of tooth preparation Preparation of the root canal Preparation of the coronal tooth structure 4/8/2023 M.Hosny 69 1. Removal of endodontic filling material With rotary instruments With warm endodontic plugger 4/8/2023 M.Hosny 70 2. Preparation of the root canal The purpose of the root canal preparation 1. To remove the undercuts. 2. To prepare the canals to receive appropriate post size. 4/8/2023 M.Hosny 71 For ready-made posts 4/8/2023 Enlargement of the root canal for a prefabricated post 4/8/2023 M.Hosny 73 4/8/2023 M.Hosny 74 For custom-made posts 4/8/2023 M.Hosny 75 3. Preparation of the coronal tooth structure 4/8/2023 M.Hosny 76 Prepare the remaining tooth as it was not damaged Remove caries and/or undermined tooth structure In cast dowel and core, coronal preparation parallel to dowel insertion The root face should have two inclined planes Anti-rotational element Eliminate sharp angles and establish smooth finish line 4/8/2023 M.Hosny 77 Pattern fabrication for cast dowel crown 1. Direct technique:    Direct wax pattern Direct resin pattern Ready-made plastic burn-out post 2. Indirect technique:  4/8/2023 Full arch impression M.Hosny 78 Direct wax pattern 1. The root canal is coated with lubricant 2. Select proper size metal sprue 3. Roughen the sprue 4. Soften blue inlay wax and press into canal 5. Heat the sprue and insert inside the canal 6. Leave wax till it hardens 7. Remove and check 8. Addition of softened wax for correction 9. Build the wax pattern of the core 4/8/2023 M.Hosny 79 Direct resin pattern https://www.youtube.com/watch?v=QFB50gSRGIs 4/8/2023 M.Hosny 80 Ready-made plastic burn-out post 4/8/2023 M.Hosny 81 Full arch impression 4/8/2023 M.Hosny 82 4/8/2023 M.Hosny 83 Core fabrication The core is either:  4/8/2023 Casted M.Hosny 84  Build-up: o o o 4/8/2023 Amalgam Composite Reinforced glass ionomer M.Hosny 85 Dowel crown for multi-rooted teeth 4/8/2023 M.Hosny 86 4/8/2023 M.Hosny 87 Cementation  The luting agent must fill all dead space within the root canal system  A rotary (lentulo) spiral filler or cement tube is used to fill the canal with cement  Inserted gently to reduce hydrostatic pressure 4/8/2023 M.Hosny 88 Procedure For Post Insertion 4/8/2023 M.Hosny 89 4/8/2023 M.Hosny 90 Endocrown An Alternative Approach For Restoring Extensively Damaged teeth Def. This monolithic (One-piece), ceramic adhesive restoration requires specific preparation techniques, which is anchored to pulp chamber & to the cavity margins, thus obtaining macromechanical retention (provided by the pulpal walls), and micro retention (by using adhesive cementation). 4/8/2023 M.Hosny 91 Indication  Cases of molars with short, obliterated, dilacerated, or fragile roots.  Excessive loss of coronal dental tissue  Limited interocclusal space  Short clinical crown Limited use in anterior & premolar teeth  Because they fall under more destructive oblique forces  Small sizes & decreased bonding area. 4/8/2023 M.Hosny 92 Advantage;  Less destructive as comparative to conventional dowels &core technique.  Less chair time  Easy and quick to perform, compared with traditional single crowns with dowels and cores.  Masticatory stresses received at the tooth/restoration interface are more properly dissipated along the overall restored tooth structure when endocrowns are placed. 4/8/2023 M.Hosny 93 Preparation steps 4/8/2023 M.Hosny 94 4/8/2023 M.Hosny 95 4/8/2023 M.Hosny 96 1. Contemporary of fixed prosthodontics. {5th edition} Pages {278-315} 2. The Dental Reference Manual Pages {84-109} 3. GROSSMAN’S ENDODONTIC PRACTICE {14TH EDITION} 97 M.Hosny 4/8/2023