Complication & failure of dental implants / cosmetic dentistry training


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Complication & failure of dental implants / cosmetic dentistry training

  1. 1. 1 By PUSHKAR GUPTAPUSHKAR GUPTA PG Student, Dept. of Prosthodontics INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. 2 INTRODUCTION The use of dental implants has enabled the fabrication of highly functional and esthetic restorations and improved the predictability of treatment. However, at any point during rehabilitation and maintenance complications and failure can occur.
  3. 3. 3  Improper Patient Selection  Surgical complication Intraoperative Postoperative complication complication  Prosthetic Complication
  4. 4. 4 IMPROPER PATIENT SELECTION The critical selection of patients and the critical application of dental implants are the two most important pre requisites for the treatment success we all desire (Lanney 1986)
  5. 5. 5 BONE DENSITY  A key determinant for clinical success  Highest clinical failure rates have been reported in posterior maxilla  Linkow in 1970 classified bone density into three categories.
  6. 6. 6 Class I : Consist of evenly spaced trabeculae with small cancellated spaces. Class II : Consist of slightly larger cancellated spaces with less uniformity of the osseous pattern Class III : Large marrow filled spaces exist between bone trabeculae
  7. 7. 7 In 1988 Misch classified bone density into D1 Dense cortical bone D2 Thick dense to porous cortical bone on crest and coarse trabecular bone within D3 Thin porous cortical bone on crest and fine trabecular bone within D4 Fine trabecular bone D5 Immature, nonmineralized bone
  8. 8. 8  As the bone density decreases the strength of the bone also decrease.  Stress can be reduced by : A. decreasing the cantilever length B. Narrowing the occlusal table design. C. Wider implants D. HA Coatings  0.5mm increase in width – 10% - 15% increase in surface area.
  9. 9. 9 AVAILABLE BONE  As a general guideline 1.5mm of surgical error is maintained between the implant and any adjacent landmark.  The height of the available bone is measured from the crest of the edentulous ridge to the opposing landmark such as the maxillary sinus or mandibular canal in the posterior region.  The anterior region are limited by the maxillary nares or the inferior border of the mandible.
  10. 10. 10  After estimating the available bone height by panoramic radiograph, the implant is selected accordingly.
  11. 11. 11  Another criteria is bone width, which is measured between the facial and lingual plates at the crest of the implant site.  Root form implant of 4.0mm crestal diameter usually require more than 5.0mm of bone width to ensure sufficient bone thickness and blood supply around the implant for long term success.
  12. 12. 12  Placing implant of 10mm length in division D bone without bone augmentation will lead to perforation of anatomical landmarks or impingement of nerves leading to parasthesia.  Hence selection of implant after estimating the available bone is one of the way of reducing complication and implant failure.
  13. 13. 13 DIABETES MELLITUS  More prone to infection  Slow healing  tissue necrosis  A ten day regime of broad spectrum antibiotics should be begun on the day of surgery to reduce the risk of infection.  High success rate is reported when dental implants are placed in diabetic patients whose disease is under control.
  14. 14. 14  Kapur et al in 1998 compared 37 diabetic patients who received conventional removable mandibular overdentures versus 52 who were fitted with implant supported ones and concluded that implants can be successfully used in diabetic patients under control.
  15. 15. 15 SMOKING  Nicotine  50% reduction in oxygen to the bone  Have greater risk of developing peri implantitis. Increased resorption of peri implant bone If untreated Implant Failure
  16. 16. 16  Failure rate of 11.28% for smokers compared to 4.76% for non smokers have been reported. (Senerby and Roos).  Smoking cessation will results in improved periodontal health and improve a patient chance of successful implant osseointegration.
  17. 17. 17 BRUXISM  The most common cause of early loss of rigid fixation is parafunctional habits.  Such complications occur with greater frequency in the maxilla because of decreased bone density.  A 37 – year old patient with a long history of bruxism recorded a maximum bite force of more than 990 Psi (4-7 times normal).
  18. 18. 18  The best and easiest way to diagnose bruxism is to evaluate the wearing of teeth.  It is not a contraindication for implant dentistry, but once the source of additional force on the implant system is identified, the treatment plan is altered to lower the negative impact on the implant, bone and final restoration.
  19. 19. 19 PATIENT UNMOTIVATED TO CONTROL PLAQUE  Not good candidates for dental implant  Accumulation of plaque on the implant surface (if not treated) will lead to peri-implantitis.  Management includes patient motivation to oral hygiene procedure and regular follow up.
  20. 20. 20 OSTEOPOROSIS  It is age – related disorder characterized by decreased bone mass and susceptibility to fracture.  Placement of implant in patient with osteoporosis will significantly effect the success rate.  Implant design should be greater in width and coated with HA to increase bone contact.
  22. 22. 22 HEMORRHAGE Bleeding may result from Soft dissection Intraosseous surgery Managed by applying Managed by forcing pressure for 5-10mins sterile bone wax into bleeding site.  Placement of implant itself in the final prepared osteotomy ceases bleeding .
  23. 23.
  24. 24. 24  Perforation on the lingual aspect of the alveolar process in the distal segment of the jaw causes lingual artery injury.  This may lead to life threatening airway obstruction.
  25. 25. 25 INFERIOR ALVEOLAR NERVE INJURY  When an instrument or the implant contacts the nerve, the patient experiences a pain sensation even under anesthesia.  Implant installation should postponed and a shorter implant should be placed at a later date.
  26. 26. 26 LINGUAL NERVE INJURY  Damage to the lingual nerve leads to loss of sensitivity in the anterior two thirds of the tongue.  This can be prevented by avoiding any type of release incision in the lingual direction.  Incisions must always be crestal, with vestibular release incisions.  Flaps on the lingual side must be elevated carefully, in tight contact with the bone.
  27. 27. 27 OPENING THE NASAL OR MAXILLARY SINUSES  After completion of implant bed preparation the bed should be carefully probed, to identify any possible perforation.  If an oro-antral or an oro-nasal tract is detected radiographs must be taken immediately.  If perforation is minor, a shorter implant is placed and the patient is completely informed.  Antibiotic coverage prescribed.
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  29. 29. 29 BROKEN BUR  Occurs when the bur gets bind to the bone and an effort is made to remove it by wriggling the handpiece shank.  Prevention  grasp the handpiece beneath its head at the point of bur emission with the thumb and fore finger and press the fingers together.  The bur is pinched between its head and the bone, and forced it vertically upward and out of the bone in a non-torque influenced movement.
  30. 30. 30  If broken bur occur  radiograph taken  Usually broken bur is deep in the osteotomy  Patient informed  Aggressive attempts to remove the bur should be avoided  If bur is not in a critical location it is best to leave it untouched.
  31. 31. 31 OVERSIZED OSTEOTOMYOVERSIZED OSTEOTOMY Cause  Lack of experience Prevention  Bone tapping and implant seating  ultra low speed handpiece  Using a mark on the rotary instrument to dictate the exact moment to reverse the motor direction.  Safer approach – stop the motor at a point four to five rotations from final seating and complete the procedure with the hand held ratchet
  32. 32. 32 Treatment  Large diameter implant  If osteotomy becomes oversized, for an implant system where there is no larger diameter implants then remove the implant and place some particulate hydroxyapatite graft material and then place the implant.
  33. 33. 33 FETAL AIR EMBOLISMFETAL AIR EMBOLISM Cause  Injection of a mixture of air and water through the hollow dental drill directly into the mandible, into the facial and pterygoid plexus veins, and hence the superior vena cava and right atrium.  Death occur from improper use of a cooling spray of compressed air and water for apical internal irrigation.
  34. 34. 34 Prevention  High speed turbine drill with lateral escape route  Suction placed closed to the cutter creates a negative local pressure that eliminates any risk of air embolism.
  35. 35. 35 ACCIDENTAL SWALLOWINGACCIDENTAL SWALLOWING  Many implant components are small, when coated with saliva escape clinicians grip and fall into oropharynx.  If this occurs, patient should be placed immediately with head down position to recover the lost component.  If this proves impossible, transported with head low position to the hospital for endoscopic examination.
  36. 36. 36 PreventionPrevention  Use of manual screw drivers and similar instruments equipped with safety wire of dental floss (min.10cm long) Correction  Specially trained medical team needed for non- invasive endoscopic removal of large components.  Very small components – High fiber diet for patient.
  37. 37. 37 FRACTURED CORTICAL PLATESFRACTURED CORTICAL PLATES  Cause – misdirection of a drill  Presence of an unexpected anatomic irregularity  If periosteum is attached to cortical plate- good prognosis.  If the fragment becomes detached, it can be wedged back into position, but the prognosis is guarded.
  38. 38. 38 MANDIBLE FRACTUREMANDIBLE FRACTURE  Manson et al 1990 – said that fracture of mandible in connection with the placement of dental implants is relatively rare. Fracture can occur During bone Excessive stress site preparation during mouth opening
  39. 39. 39 Factors responsible for fracture Atrophic thin mandible Multiple implant placements Increased vulnerable Mechanical strength is To thermal injury Decreased
  40. 40. 40 PreventionPrevention  Limited stress to jaw during healing period  Avoid over tightening of screws  Do not use wide diameter implants with large threads Management  Immediate implant retrieval from fractured bone  Rigid connection of osseointegrated implants with rigid external fixation in order to obtain immediate stability.  Soft diet for 45 days
  42. 42. 42 HEMATOMAHEMATOMA Prevented by  Proper intraoperative hemorrhage control  Careful post operative compression of the mucosa flaps covering the implants  Immediate application of cold packs  In case of extensive hematoma – antibiotics are prescribed to prevent secondary infection.
  43. 43. 43 INCISION LINE OPENINGINCISION LINE OPENING  It is the most common post operative complication  If the design of the removable interim prosthesis is involved, it is corrected  The patient is instructed to rinse 2-3 times daily with chlorhexidine and gently debride the incision line with a soft brush  Within few days to weeks the soft tissue will granulate into the opening.  Resuturing is contraindicated.
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  45. 45. 45 CHRONIC PAINCHRONIC PAIN  Implant placed close to mandibular canal may cause irritation of the inferior alveolar nerve  Such patients may experience chronic pain  Even in the advanced stages of peri-implantitis, the inferior alveolar nerve may become effected.  Antibiotics are prescribed followed by removal of the implant as soon as the acute symptoms subside.
  46. 46. 46 RADIOLUCENCIESRADIOLUCENCIES  If, at 4 or 8 weeks postoperative examination, the radiographs shows periimplant lucency, osseointegration will not occur.  The patient is informed and the implant is removed.
  47. 47. 47 INFECTIONINFECTION  Characterized clinically by - Pain - Swelling - Suppurative exudate from the wound  1 or 2 sutures are removed for drainage of pus  If the patient experiences fever, an antibiotic regimen is indicated.
  48. 48. 48 IMPLANT EXPOSUREIMPLANT EXPOSURE  Cause - Suturing the flaps under tension - Pressure from soft tissue borne prosthesis  The wound is left open  The denture is modified so as no to exert force on the area of implant exposure.
  49. 49. 49  Patient is instructed to use dry cotton – tipped applicator to keep it free of material alba.
  50. 50. 50 IMPLANT MOBILITYIMPLANT MOBILITY  Due to - Bone necrosis - Implant movement - Infection  Patient should be informed about the situation and the implant should be removed to prevent further damage. Infection (+) (-) Implant installation is Larger diameter implant postponed placed
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  52. 52. 52 LACK OF OSSEOINTEGRATION  Osseointegration is a contact established between normal and remodeled bone and an implant surface without the interposition of non bone or connective tissue.  Three are two ways of implant retention (de Putter et al 1985). Mechanical Bioactive Metallic substrate system HA
  53. 53. 53 Causes (Meffert)  Premature loading, earlier than initial healing phase  Apical migration of junctional epithelium  Placing the implant with too much pressure  Over heating the bone during site preparation  Implant not fitting the site exactly.
  54. 54. 54 Carlsson et al created bone to implant gap of 0mm, 0.35mm, and 0.85mm respectively in rabbit tabiae. Those with a gap of 0mm had direct bone to implant contact. A 0.35mm gap resulted in few areas of direct bone to implant contact and 0.85mm gap resulted in no direct bone to implant contact, indicating the need for close approximation between bone and implant for rigid fixation.
  56. 56. 56 CRITERIA FOR IMPLANT SUCCESS (Smith & Zarb)  Individual unattached implant should be immobile  No evidence of peri-implant radiolucency  Mean vertical bone loss less than 0.2mm annually after the first year of function or service.  No persistent pain, discomfort, or infection attributable to the implant  There is an 85% success rate at the end of a 5 year postrestorative period, with an 80% success rate at the end of 10 years postrestorative or function.
  57. 57. 57 SCREW LOOSENING AND FRACTURE  More common in maxilla 50% than mandible 20% Causes  Inadequate torque application  Inaccurate framework abutment interface  Arch form  Cantilever extension
  58. 58. 58 INADEQUATE TORQUE APPLICATION  Recommended torque for prosthetic gold screws is 10 Ncm and for abutment screw is 20 Ncm  A manual torque converter is available to adjust torque between 10 Ncm and 20 Ncm.  It is recommended that all screws be tightened with a torque driver.
  59. 59. 59  Patients are advised at the prosthetic delivery appointment and during hygiene recall appointments to monitor for prosthesis loosening.  If movement is present, saliva can be seen percolating at the interface  The prosthesis is removed and all components are examined.  If any of the screws are loose, they are replaced.
  60. 60. 60 ARCH FORM  When an arch form is maintained a tripod effect lessens bonding moments transmitted to the screw joint.  The destructive forces cause loosening of prosthetic and abutment screws as well as fracture of the screws.
  61. 61. 61 Groove Turn the Screw Screw Removed
  62. 62. 62 CANTILEVER EXTENSION  The cantilevered distance beyond the distal implant determines the lever arm length and the amount of force that is transmitted to the implants, framework and component.  For mandible 15mm or less  For maxilla 10mm or less  Factors - Arch form - Bone quality - Parafunctional habits  Over extension of the cantilever may lead to Screw loosening Prosthesis Implant loss or Fracture loosening
  63. 63. 63 INACCURATE FRAMEWORK ABUTMENT INTERFACE  An ideal framework abutment connection is one that has circumferential contact and is without an opening at the interface.  A non passive fit will create stresses in the screws and on the implant Screw loosening and lack of osseointegration
  64. 64. 64  When evaluating the fit, screws should be tightened one at a time while observing the lift of the frame and the open interfaces.  Torquing all screw before evaluating the interface may bend the framework giving the appearance of accuracy.  If these frames are allowed to seat will cause constant stress on the implant and the component.
  65. 65. 65 IMPLANT FRACTURE  Fractures occurs due to Fatigue Trauma  The most frequent area of fracture is just below the abutment level.
  66. 66. 66  Treatment includes removal of the fragments  Usually apical portion of the implants is osseointegrated and should be left behind, if not to be replaced, to prevent further osseous loss (Maeglin 1988)
  67. 67. 67 ESTHETIC COMPLICATION  It is a major problem in maxillary anteriors due to - Labial inclination of implants - Gingival recession  Implant inclination can be corrected using angled abutments upto 30°  Gingival recession requires mucogingival surgery for correction.
  68. 68. 68  Gingival margin, normally follows crestal bony margins.  Gingival recession often occurs if the facial plates of the bone is lost or if it is extremely thin following implant insertion.
  69. 69. 69 FRAMEWORK FRACTURE  A cross sectional dimension of at least 4mmx6mm is needed.  Common areas of framework fracture are : - Solder joints - Distal to the distal most implant
  70. 70. 70  Zarb et al 1990 – reported an increased incidence of framework breakage if extensions in the mandible exceed 20mm.  The fractured solder joint is reindexed intraorally and then soldered.  The heat of soldering will destroy any acrylic veneering material, which is replaced after the framework fit has been verified after soldering.
  71. 71. 71 UNFAVOURABLE IMPLANT LOCATION AND AXIS ORIENTATION  Esthetics, phonetics, hygiene and prosthetic design may be compromised by poor implant position. In extreme situations, implants may be so poorly positioned that it is impossible to include them in the treatment plan.
  72. 72. 72  Block et al 1990 – demonstrated that implants with an axis orientation angle of greater than 30° were more likely to be associated with peri-implant bony defects.  17° or 30° of angulation can be corrected by placing angulated abutments.
  73. 73. 73  Ailing Implants  Failing Implants  Failed Implants
  74. 74. 74 AILING IMPLANTSAILING IMPLANTS  It is least seriously affected of the three pathologic states.  Exhibits soft tissue problems (Peri-implant mucositis.  Have a favourable prognosis.
  75. 75. 75 FAILING IMPLANTSFAILING IMPLANTS  Shows evidence of - Pocketing - Bleeding upon probing - Purulence - Progressive bone loss  Have a poorer prognosis when compared with Ailing Implants  If properly treated, a failing implant may be saved.
  76. 76. 76 FAILED IMPLANTSFAILED IMPLANTS  Horizontal mobility beyond 0.5mm  Rapid progressive bone loss  Pain during percussion or function  Continued uncontrolled exudate  Generalized radiolucency around an implant  More than one half of the surrounding bone lost around an implant  Implant inserted in poor position making them useless for prosthetic support. (Sleepers)
  77. 77. 77 MAINTENANCE GUIDELINES  The long term success of the dental implant lies to a great extent, in the ability of the patient to control daily plaque.  A twice daily for 30 sec. Chlorhexidine rinse is recommended for at least 1 week after stage 2 surgery.  A soft tooth brush or flat end-tuft brush is used in addition to
  78. 78. 78  Plastic sealers are used to remove calculus  Metal instruments, including ultrasonic scalers, are not recommended. Rough surface Plaque accumulation
  79. 79. 79  After removal of hard deposits the prosthesis and abutments are selectively polished with a Rubber cup Flossing cord  Aluminum oxide polishing paste is recommended to avoid scratching of the titanium abutments and prosthetic suprastructure.
  80. 80. 80 MAINTENANCE INTERVALS  Appropriate recall intervals are determined on an individual basis, taking into consideration the patient’s history and present evaluation.  At prosthesis delivery - Oral hygiene instruction given  One month after prosthesis delivery - Review of home care techniques - Calculus removal and coronal polish  Three months later - Examination of tissues - Calculus removal and coronal polish - Establishment of a recall interval between 3 & 6 months
  81. 81. 81 CONCLUSION  There are three most basic principles for implant therapy.  Do not harm  Evaluate risks and benefits  Avoid over treatment  One should not have heroic effect  Implant therapy should only be provided when all of the pre requisites for success are present and when the patient can be better served by means of implant prosthesis treatment than by conventional prosthetic replacement.
  82. 82. 82 BIBLIOGRAPHY  The Branemark implant system – John Beumer (III)  Implant prosthodontics - Stevens  Implant dentistry – Carl E.Misch  Atlas of oral implantology – A Norman Cranin  Implantology - Hubertus Spiekermann  Implants and restorative dentistry – Carl E. Misch  Clinical Periodontology – Carranza
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