Implant Failures.pptx

Failures in Implants 1 Contents… Introduction Definitions Predictors of implant success or failure Warning signs of implant failure Criteria for implant success: Implant quality scale: Classifications of implant failures.Enhancing outcome in esth...

Failures in Implants 1 Contents… Introduction Definitions Predictors of implant success or failure Warning signs of implant failure Criteria for implant success: Implant quality scale: Classifications of implant failures.Enhancing outcome in esthetic implant dentistry.implant maintenance Conclusion Bibliography 2  Introduction Implant dentistry is currently being practiced in an atmosphere of enthusiasm and optimism, because our knowledge and ability to provide service to our patients has expanded so greatly in such a short period. But Success cannot be guaranteed, what one can guarantee is to care, to do ones best and to be there to help in the rare instance that something goes wrong 3  s is t h e a b i l it y to Succes om fa il u r e to f a i lu re go fr h ou t lo s in g y o u r wit enthusiasm 4  is not the end And failure the o p p o r tu n ity Failure is l li ge ntly g a in , m o re in te To be gi n a 5  ………When implant fails……then………. The surgeon’s tale ‘The implants were successfully integrated , but failed because of excess loads. or The Restorative Dentist’s tale ‘The implants were poorly integrated and so failed under normal masticatory loads.’ either way The Patient’s tale ‘My implants have failed!’ 6  Actually ,Success & Failure of the implants depends upon team work i.e.the co-operation b/w Surgeon, Prosthodontist, Periodontist, lab technician & the Patient. 7  Definitions … IMPLANT FAILURE… It is defined as total failure of the implant to fulfill its purpose (functional, esthetic or phonetic) because of mechanical or biological reasons. (Askary et al ID 1999 vol8 no2 173-183) 8 Ailing implants: Those that show radiographic bone loss without inflammatory signs or mobility. Failing Implant: Characterized by progressive bone loss, signs of inflammation and no mobility. 9 Failed Implants: Those with progressive bone loss, with clinical mobility and that which are not functioning in the intended sense. Surviving implants: Described by Alberktson, that applies to implants that are still in function but have been tested against the success criteria. 10 Predictors of implant success or failure ( General dentistry 2005, 423-432) Positive factors  Bone type (type 1and 2)  Patient less than 60yrs old  Experienced Clinician  Mandibular placement  Implant length > 8mm  FPD with more than two implants  Axial loading of implant  Regular postoperative recalls  Good oral hygiene 11 Negative factors Bone type (type 3 and 4) Low bone volume Patient more than 60yrs old Limited clinician experience Systemic diseases Auto-immune disease Chronic periodontitis Smoking and tobacco useUnresolved caries, endodontic lesions,frank pathology Maxillary, particularly posterior region Short implants ( Distal C……. …Cantilever extensions cause load magnification and overloading of the implant next to the cantilever extension, which in turn leads to bone loss …With occlusal forces acting on the cantilever, the implant becomes a fulcrum and is subjected to rotational forces 48  Etiology : restorative facto Amount of force increases if… …Length of cantilever …distance between implants …crown height …direction of force …position of arch Opposing arch… …ideally a denture …no lateral forces on cantilever Not preferred ----moderate to severe parafunctional habits 49  Etiology : restorative facto Connecting implants to teeth… Not preferred… Difference b/w implant & tooth movement in vertical & lateral direction 50  Etiology : restorative facto Solution… …… increase no. of implants …… improve stress distribution by splinting additional abutment until 0 clinical mobility is observed. …… non-rigid connection – but chances of intrusion of the tooth. Criteria… 1) no observable clinical mobility of natural abutment. 2) no lateral force should be designed on prosthesis. 51  Etiology : restorative facto Pier Abutments… Main complication d/t difference of mobility of tooth & implant …2 situations arise… Implant as pier Tooth as pier Act as class 1 lever …Tooth act as living pontic or Non rigid attachment pontic with a root …stress breaker –not indicated 52  Etiology : restorative facto No passive fit… One of the most critical elements affecting the long-term success of a multiple implant restoration is the passive fit between the framework and the underlying fixtures. A passive fit reduces long term stresses in the superstructure, implant components, and bone adjacent to the implants. A poorly fitting implant framework can cause mechanical complications such as loose screws or fractured components. 53  Etiology : restorative facto Improper fit of abutment… Improper locking b/w abutment-fixture interface Increased microbial population & increased strain on implant component Bone loss Rapid screw-joint failure 54  Etiology : restorative facto Improper occlusal scheme… Important guidelines to follow Infraocclusion upto 30 microns of implant supported restoration No balancing contacts on cantilevers. No guidance on single implants. Freedom in centric. Occlusal table directly proportional to implant diameter. Narrow occlusal width. Implant length: crown-root ratio ideal – 1:2 , Acceptable – 1:1 for removable denture. Avoidance of cantilever length. Maximum 10 to 15 mm is advised. 7 mm is optimum. Shallow central fossae with tripodal cuspal contacts. No contact in lateral excursion. Slight contact in centric occlusion. 55 According to timing of failure Before stage II After stage II After restoration 56  First stage surgery Problem Possible cause Solutions Hemorrhage during drilling Lesion or injury of an artery -The implant placement will stop the bleeding. -Simple tamponade , bone wax, gelfoam , surgicel , avitene can also be used Implant mobility after Soft bone Remove the implant and replace with placement Imprecise preparation one of larger diameter. If the mobility is small prolong the healing time Exposed implant threads Too narrow crest Cover the threads with coagulum or place a membrane Swelling lingually directly Incision of an artery branch EMERGENCY: send the patient to a after implant placement at sublingually specialist center for coagulation of the the mandibular symphysis artery under general anesthesia 57  Injury to neurovascular bundle… The posterior mandible in particular presents significant challenge when severe atrophy leaves little, if any bone superior to inferior alveolar canal. …The solution to limited space for posterior mandible fixture placement includes detailed initial treatment planning and careful surgery to unroof the canal and move the neurovascular bundle inferiorly prior to fixture installation… 58  Second stage surgery + abutment connection Problem Possible causes Solutions Slightly sensitive but perfectly Imperfect osseointegration Cover the implant for 2-3 months immobile implant and test again Slightly painful and mobile Lack of integration Remove the implant implant Difficulty inserting a transfer Damaged inner thread of Change the abutment screw screw, gold screw or healing cap abutment screw Inability to perfectly connect Insufficient bone milling Place a local anesthesia, use a bone the abutment to the implant mill with guide, remove the bone, clean with saline solution, and replace the abutment Granulation tissue around the Traumatic placement of the Open the area and disinfect with implant head implant; compression from the chlorhexidine. If the lesion is too transition prosthesis; a lid large, consider a bone regeneration or above the cover screw grafting technique 59 Prosthetic problems Problem Possible Solutions causes Pain or sensation when Misfit between Cut the prosthesis; interlock the pieces, and solder tightening gold screws prosthesis and the prosthesis at the laboratory. Retry the (during try in of abutments prosthesis prosthesis) Loosening of one or Occlusal problem Retighten, verify the occlusion, and recheck after more prosthetic screws two weeks. at the first inspection after two week 60 Prosthetic problems Loosening of prosthetic Occlusal problem or misfit Verify the occlusion and/ or the prosthetic screws at the second between prosthesis and fit check or later abutments Reduce the extension Too large extension Change the prosthetic design. In all cases, Unfavourable prosthetic change the prosthetic screws concept Fracture of a prosthetic Occlusal problem, lack of fit If the occlusion or the adaptation of the screw or an abutment between the prosthesis and the prosthesis seems right, modify the prosthetic screw abutment or unfavourable design (reduce or eliminate extensions, prosthetic design reduce the width of occlusal surfaces, reduce cuspal inclination, add implants, etc) 61 Prosthetic problems Fracture of the Weak metal frame Remake the prosthesis; modify the prosthetic design framework end or too large (reduce or eliminate extensions, reduce width and extension height of occlusal surfaces, reduce cusp inclination, Bruxism or add implants, etc). parafunction Make a nightguard Implant fracture Occlusal overload Remove the implant with a special trephine drill, wait 2- 6 months, if possible, and place a wider implant. Review the prosthetic design(place more implants, etc) and remake the prosthesis 62 Prosthetic problems 1. Continuing bone loss Infection (peri- Remove the etiolgical factors (poor plaque control, around one or more implantitis) prosthesis geometry in relation to the mucosa, etc). implants Look for bacterial pockets around the natural teeth. Possibly make a bacteria test. Cut open the lesion. Adjust the peri-implant tissues (gingival graft). Consider a bone regeneration procedure 2. Continuing bone loss Occlusal overload Modify the prosthetic design (reduce or eliminate around one or more extensions, reduce the width of occlusal surfaces, implants reduce cuspal inclination, add implants, etc) 63 According to failure mode Lack of Osseointegration Unacceptable Aesthetics Functional Problems Psychological Problems 64 Lack of Osseointegration…… Adell et al proposed that lack of osseointegration can be due to…… ……Surgical trauma ……Perforation through covering mucoperiosteum during healing ……Repeated overloading with microfractures of the bone at early stages Functional problems…… Proper function of the implants is dependent on two main types of anchorage related and prosthesis related. Anchorage related factor… Osseo integration Marginal bone height Prosthesis related factor… Prosthesis design Occlusal scheme 65 Aesthetic problem…… Aesthetic outcome is affected by four factors: …Implant placement …Soft tissue management …Bone grafting consideration …Prosthetic consideration Psychological problems…… …high expectations of the patient 66 According to supporting tissue type…… …Soft tissue problems …Bone loss …Both soft tissue and bone loss 67  Soft tissue problems Gingival loss leads to continuous recession around the implant with subsequent bone loss. This will lead to a soft tissue type of failure. Significance of attached gingiva surrounding implants …facilitates impression making. …provide tigth collar around the implant. …prevent recession of marginal gingiva. …prevent spread of inflammation to deep tissue. 68  Ono,Nevin,Cappetta classified keratinized gingiva based on reflection of quantity & location in mucogingival surgery during implant placement…… Type 1- flap can be apically positioned to increase the zone of keratinized gingiva on facial side Type 2-minimum keratinized tissue on ridge but little on facial aspect Type 2 class I- gingival graft Type 2 class II- gingival graft on buccal side,69 Apically positioned flap on lingual site Type 3- no attached gingiva on the ridge or facial aspect. A gingival graft which is apically postioned to increase the Zone of attched gingiva. 70  Bone loss Bone functions as a support for the implant and that any disturbance in its function may lead to eventual loss of the implant. Loss of marginal bone occurs both during the healing period and after abutment connection Bone loss in mandible is higher during the healing period. In maxilla, bone loss is higher after abutment connection 71 Factors that contribute to marginal bone loss: Surgical trauma such as detachment of the periosteum and damage cased during drilling Improper stress distribution caused by defective prosthetic design and occlusal trauma Physiological ridge resorption Gingivitis, which if allowed to progress will lead to ingression of bacteria and their toxins to the underlying osseous structures. Both soft tissue and bone loss If failure starts from soft tissue, then it usually is considered to be due to a bacterial factor. However, if failure starts at the bone level, then it is considered to be due to a mechanical factor. Both bone and soft tissue may be involved together. 72  Enhancing esthetic outcome in implant dentistry… Prosthodontic considerations Surgical consideration Use of platelet–rich-plasma 73 Prosthodontic consideration… 1) Interim provisional restoration: Modified Essex retainer Resin bonded FPD Use of transitional implants to Support an interim provisional restoration 74  2) Prosthetic guided soft tissue healing: Custom abutment & tooth form restoration Custom tooth form healing abutment 75 Surgical consideration… Cosmetic laser soft tissue resurfacing & sculpting Creating harmony with cosmetic PD surgery 76 Use of platelet-rich-plasma …Provide blood component & source of growth factor which enhance the wound healing …3-4ml of non-activated P-R-P is sufficient for multiple implant site Hard tissue …enhancing osseointegration consideration …alveolar ridge preservation …in autogenous bone graft Soft tissue consideration Both 77  Peri- implantitis Progressive peri-implant bone loss in conjunction with a soft tissue inflammatory lesion is termed peri-implantitis. Pathological changes of the peri-implant tissues can be placed in the general category of peri-implant disease. (Lang et al 1994) Two primary etiological factors 1. Bacterial infection 2. Biomechanical overload (Newman et al 1988, 1992, Rosenberg et al 1991) 78 Classification of peri-implantitis Class I …Slight Horizontal bone loss with minimal Peri-implant defects. TREATMENT……Initial therapy for removal of etiological factors. …Surgical therapy includes cleaning the implant surface, Pocket elimination via Apicalpositioning of flap. Class II …Moderate horizontal bone loss with isolated vertical defects. TREATMENT …Initial therapy for removal of etiological factors …Surgical therapy includes cleaning the implant surface pocket …Elimination and adjunctive treatment using systemic antimicrobials 79 Class III Moderate to advanced horizontal bone loss with broad, circular bony defects. TREATMENT …Initial therapy for removal of etiological factors …Surgical therapy includes cleaningthe implant surface …pocket elimination via osseous regeneration and adjunctive antibiotic treatment Class IV Advanced horizontal bone loss with broad circumferential vertical defects as well as loss of buccal and lingual bony wall. TREATMENT.Initial therapy for removal of etiological factors.Surgical therapy includes cleaningthe implant surface,pocket elimination via bone regeneration techniques, possibly autologous bone transplants with adjunctive antibiotic therapy. 80 Mechanical complications… These are primarily related to failure of prosthodontic materials to resist forces and stresses of oral function. 81  Fractured abutment screw Tip of the explorer is placed on the top portion of the fractured abutment screw. With slight apical pressure and a counterclockwise circular motion, the fragment can often be unscrewed. Care must be taken not to damage the internal threads of the implant. ……When Screw Fragment removed ,replace with appropriate new abutment and screw. Verify seating with a radiograph prior to final torque. ……Replace prosthesis and secure with new retention screws. 82 Loose Healing Abutment Radiographic evaluation of a loose healing abutment. Removal of healing abutment indicates a distorted screw Treatment:Replace with new healing abutment 83 Loose bar… Radiograph confirms poor seating abutment. Clinical evaluation after removal of bar indicates loose abutment screw. Area of concern Diagnosis- possible loose or fractured abutment screw Treatment:Retorque abutment screw. 84 Treatment: continued 2 - Abutment screw is tightened with abutment driver. 3 - Bar is then replaced and prosthetic screws are torqued with appropriate screw driver. 85  Loose restoration… Radiographic Evaluation: Small opening at abutment-implant interface Diagnosis:Loose abutment screw Treatment: 1 - Loosen screw and remove restoration Small opening 86  2 - inspect the implant hex for damage Implant hex 3 - inspect the restoration for damage (A) No Damage to fixture or restoration …replace restoration and secure with the same Abutment hex screw.Verify seating with radiograph prior to final torque.Recheck occlusion with shimstock. (B) Damaged fixture hex and or restoration replace restoration and secure with appropriate new screw. 87  Fixture loss (Must differentiate b/w “failing” and “failed”) Failing Implant Clinical signs:progressive bone loss :soft tissue pockets and crestal bone loss :bleeding on probing with possible purulence :tenderness to percussion or torque forces Causes:overheating of bone at the time of surgery or lack of initial stability. :inadequate screw joint closure :functional overload :periodontal infection (peri-implantitis) Treatment:Interim: remove prosthesis and abutments :irrigate with Peridex :ultrasonic and disinfect all components :reinsert assuring proper screw torque :recheck passive fit of framework and occlusion 88 Failed Implant Clinical signs: …Mobility…verify fixture mobility by removing any abutments and superstructures first. …A “Dull” percussion sound has been associated with a failed implant. …Peri-implant radiolucency can be a radiographic finding often this is not evident on an X-ray Causes: :surgical compromise (overheating bone and initial lack of stability). :Inadequate screw joint closure :Too rapid initial loading :Functional overload :Periodontal infection (“peri-implantitis”) Treatment :removal of the implant 89  Fractured implant fixture head Treatment:Eventual implant removal 90 Accidental swallowing or inhalation of components and /or instruments Many implant components are as small as are the instruments used for their manipulation. When coated with saliva a component may escape the clinicians grip and fall into the oropharynx, reflex swallowing may take the component out of site almost immediately. Prevention Manual screwdrivers and similar instruments should always be equipped with a safety line of dental floss.(Minimum length of 10mm) 91 92 The following factors must be evaluated at each maintenance appointment…… …oral hygiene …implant stability (evaluate mobility) …peri-implant tissue health …crevicular probing depths …bleeding …radiographic assessment (serial) crestal bone level (expect 1.0mm marginal bone loss during first year postinsertion; 0.1mm per year anticipated thereafter ) …proper torque on screw joints …occlusion …Patient comfort and function 93 Hygiene aids…… Super - floss End tufted brushes Proxy brushes Tartar control dentrifices Mechanical instruments 94 Super - Floss Excellent for all types of implant restorations Butler Post Care Floss Aid Excellent for implant bars and fixed hybrid prostheses. 95 Butler Floss Aid is used to clean the bar including the area contacting the tissue. 96  Proxy brushes End tufted brushes 97  Plastic scalers… Plastic scalers are appropriate for cleaning around standard abutments supporting implant bar substructures, hybrid prostheses and implant supported splinted restorations. Plastic scaler tips are also available for metal handle scalers. 98  Implant supported fixed partial denture Scaler tips are designed to fit the curvature of the standard abutment. 99 Prophy paste and a rubber cup on a prophy head / handpiece can be used to polish implant bars when removal is not indicated 100 Conclusion… Failure of implant has a multi-factorial dimension. Often many factors come together to cause the ultimate failure of the implant. One needs to identify the cause not just to treat the present condition but also as a learning experience for future treatments. Proper data collection, patient feedback , and accurate diagnostic tool will help point out the reason for failure. An early intervention is always possible if regular check-up are undertaken. As someone well said, it is not how much success we obtain, but how best we tackle complex situations and failures, that determine the skill of a clinician. No, doubt, failures are stepping stones to success but not until their etiologies are established and their occurrence is prevented. 101  REFERENCES Misch : Contemporary implant dentistry Atlas of implant dentistry, Cranin Why do dental implants fail: part I : Askary et al ID 1999 vol8 no2 173-183 Why do dental implants fail: part II : Askary et al Id 1999 vol 3 : 265- 275 A.S.Sclar; Soft tissue & esthetic considerations in implant dentistry. Myron Nevins; Implant therapy. Torosian J, Rosenberg ES. The failing and failed implant: a clinical, microbiologic, and treatment review. J Esthet Dent. 1993. Failures in implant dentistry.W. Chee and S. Jivraj. British Dental Journal 202, 123 - 129 (2007) 102