implant-supported fixed prostheses

1. Implant-Supported Fixed Prostheses Wael Al-Omari

3. Endosteal Implants Plate implants (Blades) Wedge shaped or rectangular in cross section Generally 2.5 mm wide, 8-15bmm deep, 15-30 mm long One stage, lower success rate, difficult placement, large in size Cylindrical (Root Form) One stage and two stage 3-6 mm wide, 8-20 mm long

5. Cylinders (Root Form) Implants Advantages: Suitable for multiple intraoral locations Precise placement Low adverse effects at incidence of failure Predictable high success rate. Available as threaded, non-threaded, coated and non-coated with hydroxyapatite, plasma sprayed, grit blasted, and acid etched Made of titanium or titanium alloy Gold standard (Branemark system: 92% success over 15 years

6. Treatment Planning Indications Inability tom wear RPD or CD Long span bridge with questionable prognosis Unfavorable natural tooth abutments Single missing tooth in an otherwise intact dentition

8. Treatment Planning Contraindications: Acute or terminal illness Uncontrolled metabolic diseases Radiated site for previous cancer therapy Pregnancy (elective procedure) Poor motivation and poor oral hygiene Lack of clinical and or technical expertise Unrealistic patient’s expectations

9. Clinical Evaluation Visual inspection and palpation Determine adequacy of bone Relevant anatomic features Flabby excess soft tissue Bony ridges Sharp osseous formations Bony undercut

10. Radiographic Evaluation The best initial film in panoramic view. Use small radio-opaque reference object to correct for magnification error (Ball bearing) New panoramic radiography machines have standardized enlargement ratios. Bone width in anterior mandible and maxilla assessed with cephalometric film Location of inferior alveolar canal and maxillary sinus assessed with CT scans. Bone width and bony undercut also assessed with CT scans

12. Diagnostic Casts Study remaining dentition Evaluate the residual bone Analyze maxillomandibular relationships. Diagnostic wax up Check proper fixture location, alignment, and relation to remaining teeth. Surgical templates to guide surgical fixture installation.

13. Bone Sounding Used when results of radiographic and clinical examinations are inconclusive. Sounding of the bone with a probe: Under local anesthesia Needle or sharp caliper pushed through the tissue until it contacts bone

14. Principles of Implant Location Anatomic limitations Ideally, 10 mm of vertical bone and 6 mm of horizontal bone dimensions should be available. Adequate space between adjacent implants: minimum of 3.0 mm 2.0 mm above superior aspect of inferior alveolar canal 5 mm anterior to mental foramen 1.0 mm from adjacent teeth.

15. Principles of Implant Location Anterior Maxilla: 1.0 mm between implant apex and nasal vestibule Implants should be located slightly off midline on either side of incisal foramen. Posterior Maxilla: Poor bone quality, minimum of 6 months for osseointegration. One implant for every tooth 1.0 mm between implant apex and maxillary sinus floor.

16. Principles of Implant Location Anterior Mandible: The most straightforward area for implant placement. Very good bone quality and quantity Place implant through the entire bone depth to engage the cortex of inferior border of mandibular border, and 5.0 mm anterior to mental foramen. Posterior Mandible: 2.0 mm above inferior alveolar canal Use short implants and place more implants Otherwise, nerve repositioning or non implant borne prosthesis

17. Restorative Considerations Implant Placement: To avoid damage: 1.0 mm from adjacent tooth. Oral Hygiene access: 3.0 mm between adjacent implants. Proper implant angulation to position screw access lingually. Long axis of implant positioned in the central fossae of restoration. Optimal emergence profile: implant positioned 2-3 mm inferior to emergence position of the restoration

20. Surgical Guide A clear resin template made from diagnostic wax up Objectives of surgical guide: Delineate the embrasures Locate the implant within the restoration contour Align implant with the long axis of the restoration. Identify the level of the emergence position from the soft tissue

22. Implant Surgery Surgical Access: crestal incision Implant Placement: Use low-speed, high-torque handpiece Avoid overheating Use series of gradually enlarged burs Avoid any contamination for the implant. Non-threaded implants are tapped into and threaded screwed into place. Implant Evaluation Implant Uncovering

23. Implant Restorations

24. Implant Restorations

26. Implant Restorations Abutments The component that screw directly into the implant fixture. In screw- retained model, abutments support the restoration. In cement retained approach, abutments are shaped like conventional crown preparation. Take many forms and angulations Made of titanium or titanium alloy or all ceramic Nonsegmented crowns: UCLA abutments

28. Implant Restorations Abutments: Correct abutment size selection is based on: Vertical distance between fixture base and opposing dentition. Existing sulcular depth. Esthetic requirements

29. Implant Restorations Impression Posts: Transfer intraoral location of implant or abutment to a similar position on the laboratory Fixture type and Abutment Type. Direct (pick-up or open-tray impression technique) Indirect (closed-tray impression technique) Impression material could be addition silicone or polyether Impression post is joined to laboratory analog Multiple divergent implants: pick-up technique

32. Implant Restorations Laboratory Analogs Represent exactly the top of the fixture or the abutment in the laboratory cast Fixture analogs and abutment analogs. Can be screwed into impression post before pouring. Gingival tissues reproduced by injecting an elastomer around laboratory analog before pouring. With fixture analog, abutment can be changed in the laboratory to correct implant angulation

33. Implant Restorations Waxing Sleeves Could be attached to abutment on lab. Model May also be directly concerted to implant body analog in nonsegmented implant crowns (UCLA abutments). May be completely plastic patterns, or combination of plastic and gold alloy cylinder Prosthesis-retaining Screws Made of titanium, titanium alloy or gold alloy Can be tightened with screwdriver or wrench Screws sunk in the crowns are covered with resilient material then sealed with composite

35. Implant Restorative Options Distal Extension Implant Restoration: Implant-tooth born prosthesis Fully implant-supported prosthesis Two implants to support 3-unit bridge Implant for each missing tooth Long Edentulous Span: Similar options. If natural tooth connected to implant use telescopic crown to protect he tooth. If soft and hard tissue missing consider use resin teeth an replace soft tissue with acrylic (Hybrid Restorations).

37. Implant Restorative Options Single Tooth Implant Requires esthetics, antirotation, simplicity and variability. Difficulty in matching the soft tissue contour of adjacent natural teeth Fixed Restoration of Completely Edentulous Arch Hybrid prosthesis: min. 5 implants in the mandible, and 6 implants in the maxilla Metal ceramic Rehabilitation: esthetic only if minimum bone loss occurred Avoid esthetic and poetic problems by avoiding placement of implants near the midline and restore maxilla incisor teeth with pontics

39. Implant Restorative Options Cement Retained Implant Crowns Simplicity, economy, allows correction of minor angle correction, , replacement of small teeth. Antirotational features are necessary Screw Retained Implant Crowns Retrievable Suffer from screw loosening Screws should be sufficiently tightened. Eliminate lateral forces and utilize antirotational features

41. Biomechanical Factors Occlusion Direct forces n long axis. Avoid long cantilevers. Minimize lateral forces. Place lateral forces as far anterior in the arch as possible. Connect implants. Proper implant angulation. Reduce occlusal table dimensions. Increase the number of implants.

42. Biomechanical Factors Connecting Implants to Natural Teeth Creates excessive forces due to differences in relative mobility Problems include failure of osseointegration, cement failure, screw loosening, and failure of prosthetic components. Solutions include, avoid connecting plant to natural teeth, telescopic coping on the natural tooth, stress breaking attachment

43. Biomechanical Factors Implant and Framework Fit Lack of passive fit results in excessive compressive forces on the interfacial bone Check passive fit with only one screw in place. Non-passive fit: section and solder Shock Absorbing Elements Designed into implant system or occlusal surface of the restoration Based only on theoretical calculations and their need is controversial.

44. Maintenance and Complications Follow-up, OHI, scaling, adjusting occlusion Bone loss: > 0.2 mm/year is alarming Bone loss of 25% to 30% necessitates revision surgery Prosthetic failure