Removal & Repair in Fixed Prosthodontics 2023 PDF

Removal & Repair in Fixed Prosthodontics Presented by Dr. Mohammed Hosny Professor of Fixed Prosthodontics Collage of Dentistry Taibah University 5/15/2023 M.Hosny 2 Outlines  Causes of removal of a fixed prosthesis  Factors affecting removing  Consideration during removing  Method...

Removal & Repair in Fixed Prosthodontics Presented by Dr. Mohammed Hosny Professor of Fixed Prosthodontics Collage of Dentistry Taibah University 5/15/2023 M.Hosny 2 Outlines  Causes of removal of a fixed prosthesis  Factors affecting removing  Consideration during removing  Method of removing  Removal of Prefab. posts or fractured cast posts.  Repair in fixed Prosthodontics 5/15/2023 M.Hosny 3 Causes of removal of a fixed prosthesis 1- After checking and verification 5/15/2023 M.Hosny 4 2- After temporary cementation 5/15/2023 M.Hosny 5 3- After permanent cementation 5/15/2023 M.Hosny 6 Why after permanent cementation? Discolored Veneering material Defective margin Remake Repair 5/15/2023 M.Hosny 7 Badly worn acrylic bridge facings Bad design Bridge with defective margins and extensive gingival inflammation 5/15/2023 M.Hosny The lateral incisor facing has chipped 8 5/15/2023 M.Hosny 9 Factors affecting removing  Restoration site  Abutment number.  Restorative material.  Pulp condition.  Type of cement.  Periodontal condition. 5/15/2023 M.Hosny 10 Consideration during removing  Suitable tip selection  Tip resting on metal margin as possible  Starting with mild force  Direction of traction  long span bridge  Crown removal not used with periodontally affected teeth 5/15/2023 M.Hosny 11 5/15/2023 12 M.Hosny Method of removing  Intact removing  Scarifies of restoration 5/15/2023 M.Hosny 13 Method of removing A. INTACT REMOVAL I. Hand instrument (spoon excavator, universal scaler). 5/15/2023 M.Hosny 14 A. INTACT REMOVAL II. Crown remover 1-Manual crown remover. 2-Spring activated crown remover. 3-Pneumatic crown &bridge remover (air-activated ). 4-ATD Automatic Crown and Bridge Remover (Air-activated device). 5-CORNA flex system (Air-activated device). 6-Richwil crown & bridge remover. 5/15/2023 M.Hosny 15 A. INTACT REMOVAL II. Crown remover 1- Manual Crown Remover 5/15/2023 M.Hosny 16 A. INTACT REMOVAL II. Crown remover 2- Spring-activated Crown Remover 5/15/2023 M.Hosny 17 A. INTACT REMOVAL II. Crown remover 3- Pneumatic Crown & bridge Remover Pneumatic crown & bridge remover (Air-activated crown and bridge remover that breaks cement seal using short, repeated, and low impact force.) 5/15/2023 M.Hosny 18 A. INTACT REMOVAL II. Crown remover 4-ATD Automatic Crown and Bridge Remover ATD Automatic Crown and Bridge Remover (Removes restorations through vibrations rather than the more typical jack hammer effect) 5/15/2023 M.Hosny 19 ATD Automatic Crown and Bridge Remover 5/15/2023 M.Hosny 20 5/15/2023 M.Hosny 21 A. INTACT REMOVAL II. Crown remover 5- CORONA flex System 1. The forceps  Position the forceps below the height of contour or at the margin of the crown.  Position the CORONA flex against the forceps arch to ensure an axial pulling direction.  Depending on the kind of cement used, several impact pulses may be necessary. 5/15/2023 M.Hosny 22 5/15/2023 M.Hosny 23 2. The loop  For removing cast post and core, bridge elements in the anterior and posterior regions. The loop is threaded under the bridge as close to the anchor tooth as possible. The loop is then connected to the loop holder. 5/15/2023 M.Hosny 24 5/15/2023 M.Hosny 25 3. The Clamp In 80% of the cases, the forceps technique prevails for crowns but the CORONA flex clamp may be an option for difficult posterior cases. 5/15/2023 M.Hosny 26 A. INTACT REMOVAL II. Crown remover 6- Richwil Crown and Bridge Remover (adhesive resin tablets) 5/15/2023 M.Hosny 27 5/15/2023 M.Hosny 28 Method of removing B. Scarifies of restoration Sectioning  Crown slitter  5/15/2023 M.Hosny 29 Method of removing B. Scarifies of restoration  Sectioning 5/15/2023 M.Hosny 30 5/15/2023 M.Hosny 31 Method of removing B. Scarifies of restoration  Crown slitter 5/15/2023 M.Hosny 32 Removal of Prefabricated posts or fractured casted post 5/15/2023 M.Hosny 33 1- Post Removal by extractor It includes  Pliers  Trephine bur  Tap or mandrel used to modify and engage the post 5/15/2023 M.Hosny 34 5/15/2023 M.Hosny 35 5/15/2023 M.Hosny 36 2- Post Removal by Ultrasonic Device 5/15/2023 M.Hosny 37 3- Post puller (Eggler post remover) 5/15/2023 M.Hosny 38 5/15/2023 39 M.Hosny REPAIR In Fixed Prosthodontics practice, it is not unusual to meet some failures within the restorations. At this point a decision has to be made whether to: 1- Leave the restoration alone if it is not causing any serious harm. 2- Repairing the defect. 3- Removing and replacing the whole restoration. 5/15/2023 M.Hosny 40 5/15/2023 M.Hosny 41 Occlusal Repairs Occlusal defects in metal retainers can be usually restored in situ Non-Precious alloys Gold Alloys Amalgam Gold inlay OR it can be soldered in the lab by free hand soldering. 5/15/2023 M.Hosny 42 Intraoral Repair of Fractured Ceramic facing with exposed metal substructure Provide adequate isolation with rubber dam 5/15/2023 Preparing the metal surface Preparation of the defective ceramic M.Hosny 43 Clean the surfaces and apply hydrofluoric etching gel on ceramic and exposed metal surface and leave to react for 20 secs. Rinse thoroughly with water Dry with oil-free air 5/15/2023 M.Hosny Apply the Silane coupling agent to the ceramic surface and leave to react for 60 secs and then dry with oil-free air. Then apply the Metal primer to the exposed metal surface and leave to react for 180 secs 44 Apply a layer of 0.5 mm of Opaquer exclusively on the conditioned metal surface. Cure with light for 20 secs. Apply a thin layer of Bonding liquid on the entire surface to be repaired 5/15/2023 Remove excess with oil-free air and polymerize with light for 20 secs. M.Hosny 45 Repair with the selected composite shade in layers of max. 2mm. Finishing and polishing with fine diamonds. 5/15/2023 Polymerize for 20 sec. Completed repair of restoration. M.Hosny 46 5/15/2023 M.Hosny 47 5/15/2023 M.Hosny 48 5/15/2023 M.Hosny 49 5/15/2023 M.Hosny 50 Repairing Zirconia  Zirconia has gained considerable popularity because of its strength, biocompatibility and aesthetics in dentistry  There are 2 types of zirconia : A. Layered (veneered) B. Monolithic (fully-contoured)  Chipping of zirconia veneered is the most common failure in zirconia restoration  Check Agingu, Chang-yuan Zhang, Neng-wu Jiang, Hui Cheng, Mutlu Özcan & Hao Yu (2018): Intraoral repair of chipped or fractured veneered zirconia crowns and fixed dental prosthesis: clinical guidelines based on literature review, Journal of Adhesion Science and Technology, DOI:10.1080/01694243.2018.1443639 5/15/2023 M.Hosny 51 Repairing Zirconia Classification of chipping  The chipping of veneered zirconia-based restorations can be classified by severity as follows: Grade 1: Small surface chipping. Grade 2: Moderate surface chipping Grade 3: Severe veneering porcelain chipping exposing the zirconia framework. 5/15/2023 M.Hosny 52 Grade 1: small surface chipping.  The surfaces can be finished and polished with fine diamond rotary burs, followed by the use of polishing kits and diamond polishing paste. Grade 2: moderate surface chipping Grade 2-1: Chipping without zirconia framework exposure Grade 2-2: Chipping with zirconia framework exposure 5/15/2023 M.Hosny 53 Grade 2: moderate surface chipping Grade 2-1 chipping without zirconia framework exposure  1. adhesion is combination of 3 ways: Macro-mechanically (e.g. chair side air-abrasion with aluminum oxide particles and diamond rotary instruments), 2. Micro-mechanically (e.g. acid etching with hydrofluoric acid) for 90-180 sec according to the concentration either 5-10%. 3. Chemical adhesion (e.g. applying silane and adhesive resins). 5/15/2023 M.Hosny 54 Grade 2: moderate surface chipping Grade 2-2 chipping with zirconia framework exposure Surface modification (cojet 3M)  Zirconia can also be bonded to silane if Tribochemical coating is performed in advance.  The ceramic substrate surface is sandblasted with a compressed air stream of 30 μm diameter size silica-coated alumina particles.  The silica-enriched surface will then react with the silane.  Adhesive resins and primers that contain MDP monomers can promote the adhesion of composites to zirconia 5/15/2023 M.Hosny 55 Classification of chipping Grade 3: severe veneering porcelain chipping exposing the zirconia framework   When the fracture surface extends into a functional area The prosthesis should be replaced Repairing system include: 1. Acid etching agent( hydroflouric acid or phosphoric acid ) 2. Ceramic priming agent (silane and/or a zirconia primer) 3. Adhesive resin 4. Repair composite (Large-sized-particle containing or hybrid-type) 5/15/2023 M.Hosny 56 The most common 5 mistakes when Repairing a porcelain fracture 1- Failure to identify the underlying cause:  Evidence of clenching and bruxism  Thin copings that flex at the margin causing fracture at the facial margin.  Long spans with pontics that bounce under occlusion. 5/15/2023 M.Hosny 57 2- Failing to properly prepare the porcelain Beveling the fractured ceramic with a diamond offers many advantages: a- It removes the loose or unsupported fragments. b- It increases the surface area available for bonding. c- It improves the esthetics by allowing a gradual transition from the composite shade to the porcelain shade. 5/15/2023 M.Hosny 58 3- Failing to air-abrade the metal 5/15/2023 M.Hosny 59 4- Applying the composite before the adhesive has fully set.   Light-activated composites shrink as they cure. As they shrink, they are drawn toward the curing light and away from the metal substrate.  If you start curing the composite before your adhesive liner has completely polymerized, the shrinking composite may actually tear the unset adhesive off the metal. 5- Implying to the patient that the composite repair is permanent. 5/15/2023 M.Hosny 60 Any Questions REFERENCES Contemporary in fixed prosthodontics, (6th edition) Page 348 & 884 5/15/2023 61 M.Hosny Thank you…. Mohammed Hosny 5/15/2023 M.Hosny 62