implant failure

Failures in Implants

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• 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

Contents…

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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

Introduction

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Success is the ability to go from failure to failure without losing your enthusiasm

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And failure

Failure is the opportunity

To begin again , more intelligently

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is not the end

The surgeon’s tale‘The implants were successfully integrated , but failed because of excess loads. orThe 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!’

………When implant fails……then……….

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Actually ,Success & Failure of the implants depends upon team work i.e.the co-operation b/w Surgeon, Prosthodontist, Periodontist, lab technician & the Patient.

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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)

Definitions …

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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.

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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.

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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

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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 (<7mm) Eccentric loading Inappropriate early clinical loading Bruxism and other parafunctional habits

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Warning signs of implant failure (Askary et al ID 1999; vol 8; no2, 173-183)

Connecting screw loosening Connecting screw fracture Gingival bleeding and enlargement Purulent exudates from large pockets Pain Fracture of prosthetic components Angular bone loss noted radiographically Long-standing infection and soft tissue sloughing during the healing period of first stage surgery

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Criteria for implant success: …The individual implant is immobile when tested clinically. …No radiographic evidence of peri-implant radiolucency …Bone loss no greater than 0.2 mm annually …Gingival inflammation amenable to treatment …Absence of symptoms of infection and pain …Absence of damage to adjacent teeth …Absence of parasthesia, anesthesia or violation of the mandibular canal or maxillary sinus …Should provide functional survival for 5 years in 90% of the cases and for 10 years in 85%. (Albrekfsson T. :int J. Oral Maxillofac Implants 1986; 1:11-25)

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Implant quality scale: The scale presented for implant quality of health based on clinical evaluation was first suggested by James and was modified by Misch. This quality of health scale criteria, has to be place in the appropriate category, and then treat the implant accordingly. The prognosis also is related to the quality scale.

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Classification Of Implant failures

…E.S Rosenberg, J.P. Torosian and J. Slots

…Abdel Salam El Askary, Roland Mefert and Terrence Griffin

…Kees Heydenrijik, Henny JA Meijer, Wil A Van der et al

… Marco Esposito, Jan Michael Hirsh, Ulf Lekholm et al

…Sumiya Hobo, Eiji Ichida, Lily T Garcia

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1. Infectious Failure: …Clinical signs of

infection with classic symptoms of inflammation

…High plaque and gingival

indices …Pocketing …Bleeding,

Suppuration …Attachment loss …Radiographic peri-

implant radiolucency …Presence of granulomatous tissue

upon removal

2. Traumatic Failure: …Radiographic periimplant radiolucency

…Mobility

…Lack of granulomatous tissue upon removal

…Lack of increased probing depths

…Low plaque and gingival indices

A) E.S Rosenberg, J.P. Torosian and J. Slots classified as :

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B) Marco Esposito, Jan Michael Hirsh, Ulf Lekholm et al have classified oral implant failures according to the osseoi ntegration concept.

1)Biological Failures: • Early or primary (Before loading)• Late or secondary (After loading)

2)Mechanical failures:• Fracture of implants, connecting screws, bridge framework, coatings etc3)Iatrogenic Failures• Improper implant angulation and alignment,

nerve damage

4)Inadequate Patient adaptation • Phonetics, esthetics, psychological problems. 19

C) Kees Heydenrijik, Henny JA Meijer, Wil A Van der et al classified to occurrence in time as: 1) Early Failures: Causes attributed are:

• Surgical trauma• Insufficient quantity or quality of bone• Premature loading of implant• Bacterial infection2) Late Failures: Soon late failures: Implants failing during first year of loading. Overloading in relation to poor bone quality and insufficient bone volume. Delayed late failures: Implant failing in subsequent years. Progressive changes of the loading conditions in relation to bone quality, volume and peri -implantitis.

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Swedish Team( Branemark et al)

U.C.L.A team(Beumer, Moy)

1. Loss of bone anchorage:a. Mucoperiosteal

perforationb. Surgical trauma

2. Gingival problems:a. Proliferative

gingivitisb. Fistula formation

3. Mechanical complications:a. Fracture of prosthesis, gold

screws, abutment screws

1. Complications in Stage I surgery;

2. Complications in Stage II surgery:

3. Prosthetic complications:

D) Sumiya Hobo, Eiji Ichida, Lily T Garcia enlisted various complications occurring in implants as:

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E) Abdel Salam el Askary, Roland Meffert and terrence griffin …

According to etiology

Restorative factor

Host factor

Surgical factor

Implant selection factor

According to timing of failure

Before stage II After stage II After restoration

According to origin of infection

Peri- implantitis (Infective process, bacterial origin)

Retrograde peri-implantitis (Traumatic occlusion origin, non infective, forces off the long axis, premature or excessive loading) 22

According to failure modePsychological problems

Lack of osseointegration

Unacceptable aesthetics

Functional problems

According to condition of failureAiling ImplantFailing ImplantFailed ImplantSurviving Im.

According to supporting tissue typeSoft tissue loss Bone loss Combination

According to responsible personnelDentist (Oral surgeon,Prosthodontist, Periodontist)

Dental hygienist

Laboratory Technician Patient

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Restorative factor

Host factor

Surgical factor


Host factor

Medical status : Habits : Oral status

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A. Host factors…MEDICAL STATUS… medical history is essential to rule out any of the following conditions or disorders. If yes… medical consultation Bone dieases

CV Dieases

Autoimmune

Endocrine

Pregnancy

Hypertension MICongestive heart failureSABE

DM Thyroiddisorders

osteoporosis osteomalacia? hyperparathyriodism

fibrous dysplasia paget dz multiple myeloma

? osteomylitis

sjogren syndrome? SLE? scleroderma ? HIV

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Avoid to place implant in pregnancy

…In all these conditions ,chances of success rate are poor but implant therapy … not contraindicated except few.

Etiology : host factor

HABITS1) Smoking:Significance• Causes alveolar vasoconstriction and decreased blood flow• Impaired wound healing due to compromised

polymorphonuclear leucocytes function, increased platelet adhesiveness as well as vasoconstriction caused by nicotine.

• Poor bone quality• In case of poor oral hygiene, smokers have 3 times more

marginal bone loss then non-smokers

Recommendations:1.Obtain a smoking history2.Advice on risks of periodontal breakdown3.Advice on the prognosis .Smoking cessation


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Parafunctional habits:Bruxism is the multidirectional nonfunctional grinding of teeth. Clenching occurs in one direction (vertically). Bruxism is more aggressive. Attrition usually appears on the incisal edges of anterior teeth.

Significance• Most common cause of implant bone loss or lack of rigid fixation during the first year after implant insertion.• Commonly manifests as connecting screw loosening because of

overload.• Failures are higher in maxilla because of decrease in bone density.• Forces are in excess of normal physiologic masticatory load limit.

( upto 1000 psi).


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Prevention• Increased number of implants to be placed• Avoid cantilevers and occlusal contacts in lateral

excursions• Use of occlusal splint which is relieved over the implant.• Use of wide diameter implant to provide greater surface

area.Progressive bone loading and prosthetic design that improves the distribution of stresses throughout the implant system.( By Misch


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Poor home care: ORAL STATUS:

Suprabony connective tissue fibers are oriented parallel to the implant surface

Susceptible to plaque accumulation and bacterial ingress

Spontaneous loss of the perimucosal seal

Chances of implant failure increases


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Prevention

• It is recommended that the patient be recalled frequently, preferably at a minimum of 3 months intervals. Periodontal indices, bleeding on probing and radiographic evaluation should be performed, using plastic tipped probes for checking pocket depths.

• Soft tissue debridement should be performed by means of plastic curettes and plastic tips for ultrasonic scalers, and topical and systematic antimicrobial drugs should be used

• Provide space beneath the superstructure to allow cleansing aids


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IRRADIATION THERAPY

Significance• Xerostomia• Susceptibility to infection• Osteoradionecrosis• Endarteritis of vessels causes decrease in oxygen supply

Prevention• Waiting period of 9-12 month between radiation therapy and

implant treatment.• Hyperbaric oxygen therapy – 20 treatments of 90 min. each at 2 to

2.4atm before surgery.• Antibiotic regimen 3 days before (augmentin 500mg every 12 hrs).


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SURGICAL PLACEMENT… …Impaired healing and infection due to improper flap design… …Overheating the bone and exerting too much pressure… …Contamination of implant body before insertion… …Placement of implant in immature bone grafted site… …Severe angulation… …Minimum space between implants… …Lack of initial stabilization…


Restorative factor

Host factor

Surgical placement


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a) Off-axis placement (severe angulation)…

Occlusal load lie at an angle

Shear & tensile forces increases

Chances of failure increases

Problem…

Due to… A) Alveolar process resorption

B) Unexperienced surgeonC) Improper surgical stent

Etiology : surgical factor

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1) Prerestoring the implant position by grafting

2) To place the implant with an angulation.

3) To place angulated abutments.

Solutions…


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b) Lack of initial stability…Due to oversized osteotomy

Gap develop between implant & bone

Lack of osseointegration

In an experimental investigation, gaps in the range of

0.25 mm around CPTi implants healed, but with less bone contact than the controls.

When the gap size increased to 0.7mm-1.7mm, a thin soft tissue layer was found to develop around the implant.


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Solution…

Remove & reinsert the larger size implant.

if not possible remove insert HA graft material roll the implant moistened in blood & saline & in the particulate slurry until thin layer of slurry clings to it reinsert the implant


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c) Improper healing & infection because of improper flap design…

No single flap design is optimal for implant surgery.

But improper flap design infection & bacterial ingress chances of failure increases

Note: basic surgical procedure, flap design , blood supply, visibility,access, primary closure should be considered.


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d) Overheating the bone and exerting too much pressure……


Excessive pressure Bone cell damage Bone loss

Connective tissue interface formed

Failure increases

…Inverse relationship b/w speed & heat production

…Recommended speed- 2000 rpm with graded series of drill size with external irrigation

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Note: Bone cell death occurs at a temperature of 47 degree and higher when drilling is performed for 1 minute.


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e) Placement of implant in immature bone grafted site…


Minimum waiting period of grafted site…6-9 mth

woven bone present before this period, which is fastest formed bone (partly mineralized &Unorganized)

Lamellar bone ideal for implant prosthetic support

Not suitable for implant-bone integration

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f) Contamination of implant body before insertion…

D/t …non-titanium instrument …by glove powder …by the operatory error

By autoclaving the contaminated implant

Bake the bacteria on implant surface

Impossible for phagocytic cell to clean the surface

No close adaptation to the bone


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……Implant should be cleaned with radiofrequency glow discharge unit or plasma cleaner

……Metal instrument should be titanium tipped


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Restorative factor

Host factor

Surgical placement


Implant selection factor… …Improper implant type in improper bone type… …length of the implant… …width of the implant… …number of the implant… …improper implant design…

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Length of the implant..Misch proposed the range of 10mm-16mm length.

The greater the crown implant ratio, the greater the amount of the force with any lateral force. This means that the implant with unfavorable crown implant ratio will be more influenced by lateral forces. Therefore, maximum implant length must be used for the greatest stability of the overlying prosthesis.

The success rate is proportional to the implant length and the quantity and quality of available bone. The rate of failure can be expected to rise proportionately as the depth of the bone diminishes to less than 10mm.

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Width of the implant…

Misch recommended that not less than 1 mm of bone surrounding the fixture labially and lingually is mandatory for the long term predictability of dental implants because it maintains enough bone thickness and blood supply.

…it is advisable to use a large- diameter implant in accordance with the available bone width because it offers greater surface area, greater mechanical engagement of the cortical bone, and initial rigidity.

Using a wide implant in a narrow ridge results in labial or lingual dehiscence that leaves the implant affected by the damaging shear stresses. 45

Number of implants…

Misch stated that the use of more implants decreases the number of pontics and the associated mechanics and strains on the prosthesis, and dissipates stresses more effectively to the bone structure. It also increases the implant bone interface and improve the ability of the fixed restoration to withstand forces.

Contrary to this Smith et al correlated between the increased number of implants and the high failure rate caused by wound contamination that might occur because of the long operating time.

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RESTORATIVE PROBLEMS Excessive Cantilever Pier abutments No passive fit Improper fit of the abutment Bending moments Connecting implants to natural teeth Improper occlusal scheme


Restorative factor

Host factor

Surgical placement


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Excessive cantilevers…

……Used implant-supported prosthesis.

……Mesial C. > 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

Etiology : restorative factor

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Not preferred ----moderate to severe parafunctional habits

Opposing arch… …ideally a denture …no lateral forces on cantilever

Amount of force increases if… …Length of cantilever …distance between implants …crown height …direction of force …position of arch


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Connecting implants to teeth…Not preferred…

Difference b/w implant & tooth movement in vertical & lateral direction


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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.

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Pier Abutments…Etiology : restorative factor

Main complication d/t difference of mobility of tooth & implant

…2 situations arise…Implant as pier Tooth as pier

…Tooth act as living pontic or pontic with a root

…stress breaker –not indicated

Act as class 1 lever

Non rigid attachment

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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.

No passive fit…Etiology : restorative factor

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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


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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.

Etiology : restorative factorImproper occlusal scheme…

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According to timing of failure

Before stage II

After stage II

After restoration

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Problem Possible cause SolutionsHemorrhage 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 placement

Soft boneImprecise preparation

Remove the implant and replace with 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 after implant placement at the mandibular symphysis

Incision of an artery branch sublingually

EMERGENCY: send the patient to a specialist center for coagulation of the artery under general anesthesia

First stage surgery

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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…

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Problem Possible causes SolutionsSlightly sensitive but perfectly immobile implant

Imperfect osseointegration

Cover the implant for 2-3 months and test again

Slightly painful and mobile implant

Lack of integration

Remove the implant

Difficulty inserting a transfer screw, gold screw or healing cap

Damaged inner thread of abutment screw

Change the abutment screw

Inability to perfectly connect the abutment to the implant

Insufficient bone milling

Place a local anesthesia, use a bone mill with guide, remove the bone, clean with saline solution, and replace the abutment

Granulation tissue around the implant head

Traumatic placement of the implant; compression from the transition prosthesis; a lid above the cover screw

Open the area and disinfect with chlorhexidine. If the lesion is too large, consider a bone regeneration or grafting technique

Second stage surgery + abutment connection

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Problem Possible causes

Solutions

Pain or sensation when tightening gold screws (during try in of prosthesis)

Misfit between prosthesis and abutments

Cut the prosthesis; interlock the pieces, and solder the prosthesis at the laboratory. Retry the prosthesis

Loosening of one or more prosthetic screws at the first inspection after two week

Occlusal problem

Retighten, verify the occlusion, and recheck after two weeks.

Prosthetic problems

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Loosening of prosthetic screws at the second check or later

Occlusal problem or misfit between prosthesis and abutmentsToo large extensionUnfavourable prosthetic concept

Verify the occlusion and/ or the prosthetic fitReduce the extensionChange the prosthetic design. In all cases, change the prosthetic screws

Fracture of a prosthetic screw or an abutment screw

Occlusal problem, lack of fit between the prosthesis and the abutment or unfavourable prosthetic design

If the occlusion or the adaptation of the prosthesis seems right, modify the prosthetic design (reduce or eliminate extensions, reduce the width of occlusal surfaces, reduce cuspal inclination, add implants, etc)

Prosthetic problems

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Fracture of the framework

Weak metal frame end or too large extensionBruxism or parafunction

Remake the prosthesis; modify the prosthetic design (reduce or eliminate extensions, reduce width and height of occlusal surfaces, reduce cusp inclination, add implants, etc).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

Prosthetic problems

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1. Continuing bone loss around one or more implants

Infection (peri-implantitis)

Remove the etiolgical factors (poor plaque control, prosthesis geometry in relation to the mucosa, etc). 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 around one or more implants

Occlusal overload

Modify the prosthetic design (reduce or eliminate extensions, reduce the width of occlusal surfaces, reduce cuspal inclination, add implants, etc)

Prosthetic problems

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Psychological Problems

According to failure mode Lack of Osseointegration

Unacceptable Aesthetics

FunctionalProblems

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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

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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

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…Soft tissue problems

…Bone loss

…Both soft tissue and bone loss

According to supporting tissue type……

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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.

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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 graftType 2 class II- gingival graft on buccal side,Apically positioned flap on lingual site

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Type 3- no attached gingiva on the ridge or facial aspect.A gingival graft which is apically postioned to increase theZone of attched gingiva.

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Bone loss

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

Bone functions as a support for the implant and that any disturbance in its function may lead to eventual loss of the implant.

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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.

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Enhancing esthetic outcome in implant dentistry…

Prosthodontic considerations

Surgical consideration

Use of platelet–rich-plasma

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Prosthodontic consideration…1) Interim provisional restoration:

Resin bonded FPD

Use of transitional implants to Support an interim provisional restoration

Modified Essex retainer

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2) Prosthetic guided soft tissue healing:

Custom abutment & tooth form restoration

Custom tooth form healing abutment

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Surgical consideration…Cosmetic laser soft tissue resurfacing & sculpting

Creating harmony with cosmetic PD surgery

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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 consideration

Soft tissue consideration

Both

…enhancing osseointegration…alveolar ridge preservation…in autogenous bone graft

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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 factors1. Bacterial infection2. Biomechanical overload

(Newman et al 1988, 1992, Rosenberg et al 1991)

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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

Class IV

Moderate to advanced horizontalbone 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 treatmentAdvanced 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 regenerationtechniques, possibly autologous bone transplants with adjunctive antibiotic therapy.

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These are primarily related to failure of prosthodontic materials to resist forces and stresses of oral function.

Mechanical complications…

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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.

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Radiographic evaluation of a loose healing abutment.

Removal of healing abutment indicates a distorted screw

Treatment:Replace with new healing abutment

Loose Healing Abutment

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Area of concern

Radiograph confirms poor seating abutment.

Diagnosis- possible loose or fractured abutment screw

Clinical evaluation after removal of bar indicates loose abutment screw.

Treatment:Retorque abutment screw.

Loose bar…

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Treatment: continued2 - Abutment screw is tightened with abutment driver.3 - Bar is then replaced and prosthetic screws are torqued with appropriate screw driver.

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Loose restoration…

Radiographic Evaluation: Small opening at abutment-implant interface

Small opening

Diagnosis:Loose abutment screw

Treatment:1 - Loosen screw and remove restoration 86

2 - inspect the implant hex for damage

3 - inspect the restoration for damage

Implant hex

Abutment hex

(A) No Damage to fixture or restoration

…replace restoration and secure with the same 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

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Causes: :surgical compromise (overheating bone

and initial lack of stability). :Inadequate screw joint closure :Too rapid initial loading :Functional overload :Periodontal infection (“peri-implantitis”)

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

Failed Implant

Treatment:removal of the implant 89

Treatment:Eventual implant removal

Fractured implant fixture head

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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.

PreventionManual screwdrivers and similar

instruments should always be equipped with a safety line of dental floss.(Minimum length of 10mm)

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…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

The following factors must be evaluated at each maintenance appointment……

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Hygiene aids…… Super - floss End tufted brushes Proxy brushes Tartar control dentrifices Mechanical instruments

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Super - Floss Excellent for all types of implant restorations

Butler Post Care Floss AidExcellent for implant bars and fixed hybrid prostheses.

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Butler Floss Aid is used to clean the bar including the area contacting the tissue.

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End tufted brushes

Proxy brushes

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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.

Plastic scalers…

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Implant supported fixed partial denture

Scaler tips are designed to fit the curvature of the standard abutment.

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Prophy paste and a rubber cup on a prophy head / handpiece can be used to polish implant bars when removal is not indicated

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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.

Conclusion…

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