complications in impantology

© Ramaiah University of Applied Sciences

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Faculty of Dental Sciences

Complications in implantology

Dr. Zeeshan Arif


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Contents

Classification

Risk factors

Surgical problems

- stage one surgery

--haemorrhage

--edema

--flap dihescence

--implant mobility

--implant location

--problems placing cover screw

--post operative pain

--paraesthesia

--infection

--exposure following placement-stage two surgery--failure to integrate--lack of osseointegration--problems placing abutments--bony defects--painImplant related problems-pain-infectionPeri implant mucositisPeri implantitis-thread exposure-loss of integration

Biomechanical problems-screw fracturesImplant body fracture-prosthesis fractureFunctional problems-appearance-speech -MasticationConclusion References


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Introduction

• Since the introduction of the concept of osseointegration the

success of implants have increased dramatically

• Endosseous dental implants have been a successful treatment

alternative for restoring missing teeth

• However the treatment is not always successful as the implant is a

foreign body

• The research focus is shifting from description of clinical success to

identifications of factors causing implant failures


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Classificaton

– Rosenberg et al.classified implant failures as:

1. Infections

2. Traumatic


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• Esposito et al classified implants according to the Osseointegration

Concept

1. Biological

2. mechanical

3. iatrogenic

4. Inadequate patient education


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• Truhlar classified failures as

1. Early failures

2. Late failures


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• Hobo et al. listed out the various complications occurring in implants as follows:


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• According to Cranin


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• El askary et al. have divided the FAILURES into seven categories


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Systemic Factors Potential medical risks (Matukas1988):

1. Cardiovascular – Heart failure, CHD, hypertension

2. Respiratory – COPD, Asthma.

3. GIT– Nutritional disorders, Hepatitis malabsorption,

inflammatory bowel disease.

4. Genitourinary – Chronic renal failure.

5. Endocrine – Diabetes, pituitary/adrenal disease.

6. Musculoskeletal, arthritis, osteoporosis.

7. Neurologic – Stroke, Palsy.


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Absolute Medical Contraindications: -

1. Brittle diabetes

2. Haemophelia

3. Ehler-Dahnlos syndrome

4. Marfan's syndrome

5. Osteoradionecrosis

6. Renal failure

7. Fibrous dysplasia

8. Crohn's Disease


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Psychological Factors:

1. Lack of support

2. Mental retardation

3. Dementia

4. Psychosis

5. Emotional problems

6. Interpersonal problems

7. Behavioral problems - Problematic attitudes and beliefs.


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SURGICAL PROBLEMS

STAGE-ONE SURGERY

Haemorrhage

• Excessive haemorrhage usually occurs as a result of involving a blood

vessel or perforating the bony cortex so that the adjacent soft

tissues are traumatized.

• Where this occurs in the mandible distal to the mental foramina the

possibility of damage to the mandibular canal must be considered.

• Prevention of this is based on careful radiographic assessment and

surgical technique.


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• Edema is the accumulation of excess

plasma fluid (transudate) in the interstitial

spaces (at least a 10% increase).

• It is correlated to the extent of surgical

trauma and to the duration of surgery.

• Atraumatic surgical techniques

minimizing tissue damage, the application

of ice packs and the administration of

corticosteroids will prevent or limit

edema after implant surgery.


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Flap dehiscence

• Dehiscence is opening of the surgical wound edges exposing part or

all of the implant head and/or surrounding bony tissues.

• failure to ensure closure of the flap

• presence of large edema or hematomas

• insufficient or excessive tension on the suture

• previous prosthodontic surgery or radiation therapy affecting the

vascularity of the flap


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• sudden trauma by the opposing

dentition

• premature use of a removable denture

• incomplete tightening of the cover screw

• bone debris trapped under the

periosteum


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Implant mobility

• This can arise where there are problems in obtaining primary

stability because of the anatomy and density of the bone, or the

implant site has been prepared without due care.

• They can often be managed by the use of 'oversized' or tapered

implants, which a number of manufacturers provide.

• Failure to secure good primary fixation is associated with increased

implant failure


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Implant location

• Incorrect positioning of the

implant can lead to considerable

difficulties during the

restorative phase of treatment.

• It is extremely important that

implant locations are planned

with the prosthodontist prior to

surgery.


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• Minimum distance between an implant

and a tooth should be 1.5 to 2 mm.

• Lateral biologic width around an

implant is around 1.3 mm.

• Violation of this width results in bone

loss on the implant and adjacent

structures.

• Minimum distance between 2 implants

should be 3 mm to maintain

interproximal bone height.


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Problems placing cover screw

• These usually arise as a result of contamination of

the linking recess in the implant body,

misalignment of the screw or damage to the

screw threads in the implant body.

• Where necessary, the internal thread in the

implant body may have to be redefined with the

tap provided by the manufacturer, although this is

a rare occurrence


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Postoperative pain

• This is an uncommon complaint

• Where it occurs immediately after implant placement, nerve involvement, inflammation and thermal trauma should all be considered.

• Pain arising later is often related to periimplant infection, or excessive pressure from the temporary prosthesis, where one is used.

• Pain immediately following implant placement can usually be

managed with mild analgesics; however, if it persists then further

investigations are required.


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Paraesthesia

• This arises due to trauma to one of the nerves in the region of the

implant site.

• It usually subsides where direct mechanical damage to the

neurovascular bundle has not occurred.

• It is best avoided by careful preoperative assessment and surgery.


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Infection

• Infection following surgery is unusual provided that a careful sterile

technique has been used.

• There is evidence that the use of prophylactic antibiotics can reduce

both this problem and the incidence of early implant failure.

• Where infection occurs it should be managed symptomatically.


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Exposure following placement

• It is most likely to occur as a result of poor design of

the surgical flap, tension in the flap, or excessive

pressure from a temporary prosthesis or its

premature insertion.

• Where it arises the patient should be instructed to

clean thoroughly around the area, and if a denture is

being used, then this should be eased to relieve any

excessive pressure.


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STAGE-TWO SURGERY

Failure to integrate

• This is usually noted as a loose implant and is more likely to occur

where factors predisposing to implant failure are present.

• Since integration is very unlikely to be established around a clinically

loose implant at this stage, management requires its removal.

• An assessment must then be made of the implications, and

consideration given to either replacement of the implant, after a

healing period, insertion of an implant in an adjacent site, or

modification of the treatment plan using a smaller number of

fixtures.


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• Where the potential exists for increased implant failure, some

clinicians advocate the initial insertion of a generous number of

implants so that the original treatment plan can proceed, even if

some do not become integrated.

• This requires adequate space for implant insertion and resources to

pay for the additional costs.

• In this technique it is common, where failures do not occur, for some

of the implants to remain buried.

• These are known colloquially as 'sleepers'.


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• Lack of osseointegration is diagnosed at phase II surgery or

restoration when the implant is loaded.

• The main causes for lack of osseointegration include

1. reduced healing capacity,

2. occlusal loading during osseointegration,

3. failure to follow the planned protocol,

4. technical errors during surgery (such as accidental contamination

of the implant surface),

5. bone overheating during implant site preparation.


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• Clinically, lack of osseointegration is diagnosed when the implant has

loosened and a muffled sound is heard upon percussion.

• Radiographic evidence consists of a small radiolucent margin around

the implant indicating that there is no direct contact between the

bone and the implant.

• Treatment will require removal of the loose implant and accurate

debridement of the area involved so that a new implant may be

inserted after healing has taken place


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Problems placing abutment

• These frequently arise due to damage to the

internal linking features of the implant body

during implant placement, particularly if this is a

screw, or misalignment of the abutment,

producing a crossed thread.

• Contamination of the internal features of the

implant, typically by bone chips, can also cause

the problem.


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Bony defects

• A horizontal or vertical bony defect around an implant is a

complication that may be observed on assessing the bone-implant

interface at the time of phase II surgery.

• The causes that may lead to bone defects are

1. direct trauma to the bone or an insult to the periosteum reducing

vascularity,

2. decreased bone density,

3. implant placement into fresh extraction sockets,


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4) wrong inclination of the implant

5) excessive torque during insertion

6) the presence of a bone dehiscence not treated at phase I surgery

7) an extremely thin alveolar crest,

8) wound dehiscence during healing

9) perforation of the mucoperiosteum

10) postoperative infection

11) excessive loading by the temporary prosthesis


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• In the presence of: – a vertical defect of less

than 2 mm, horizontal osteoplasty can be

performed to reduce the defect without

compromising the restorations or the cosmetic

result;

• – a vertical defect of more than 2 mm involving

less than half of the implant, autologous bone

taken from an intraoral site may be grafted.


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When the bone loss is greater than

25% of the circumference of the

implant, grafting may be combined

with a membrane.


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Pain

• Pain at the time of second-stage surgery can arise prior to, during or

following the placement of the abutment.

• Pain prior to placement is indicative of infection, poor integration or

mechanical problems related to the temporary prosthesis.

• Where infection is present, this must be resolved prior to placement

of the abutment.


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• Pain during second-stage surgery is usually indicative of failure to

achieve adequate local anaesthesia.

• Where it occurs immediately after implant abutment placement, it is

often indicative of trapping of the oral mucosa between the

abutment and the head of the implant body, or inadequate seating

of the abutment due to misalignment or trapping of adjacent bone.


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IMPLANT-RELATED PROBLEMS

• Biological

• Pain

• Pain arising some time after implant placement may be associated

with mechanical overload, loss of integration, loosening of the joints

between the implant body and connecting components, infection

and mechanical failure of one of the components.


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Infection

• Infection may arise as a result of poor oral hygiene or the impaction

of a foreign body.

• Calculus on the abutment can be a significant problem.

• Attention to oral hygiene, syringing of the pockets around the

abutments using a chlorhexidine solution, and cleaning of the

abutments where necessary, using plastic sealers, usually result in a

significant improvement in the condition.

• Sometimes it is necessary to remove the abutment to aid in

irrigation of the site or scaling of the abutment.


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Peri-Implant mucositis

• This is a condition characterized by inflammation of the soft tissues

adjacent to the implant but excluding involvement of the peri-

implant bone.

• The characteristics of the condition include increased probing

depths, inflammation, swelling, ready bleeding on probing and

tenderness.

• It is associated with mechanical irritation and bacterial proliferation

in the peri-implant sulcus.


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• The condition can also arise as a result of mechanical irritation,

particularly the presence of calculus and other foreign bodies within

the periimplant sulcus, as well as a poor fit between the abutment

and the implant body.


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Peri-implantitis

• Peri-implantitis is a more severe condition, which involves loss of

bone-implant contact due to infection of the connective tissues

adjacent to the implant.

• pain around the implant

• diagnosis is by means of clinical examination, including probing of

the peri-implant sulcus.

• This will be deepened where bone loss has occurred in the crestal

region, typically all around the implant body, a finding which will

also be evident on radiographic examination.


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• Predisposing factors- smoking, poorly controlled diabetes.

• Local predisposing factors include poor plaque control, bacterial

colonization of the peri-implant sulcus, mechanical irritation and

mechanical overload of the implant-bone interface.

• The link between ongoing periodontal disease and peri-implantitis is

unclear; however, it is recommended that implants should not be

used in patients with ongoing periodontal disease.


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• Where the systemic factors are amenable to control then

management of these should be started as soon as the condition is

diagnosed.

• Local management, must be instigated as soon as possible to

minimize risk of the loss of the implant.

• Examination should include an assessment of masticatory loads,

plaque control, the presence of any foreign bodies around the

implant and fit of the implant components between each other.


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Thread exposure

• implants have been placed too superficially

• allowance has not been made for the buccal curvature of the

alveolus

• marginal bone loss has been greater than anticipated.

• bone is excessively heated during site preparation.


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Management by prevention is to be

preferred

• careful planning on a diagnostic cast

should be carried out.

• a short flange may be provided

• soft-tissue grafting to cover the defect.


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Loss of integration

• there is no sufficient bone-implant contact to maintain functionality

• It may be diagnosed radiographically as well as by looseness of the

implant

• Total loss of integration is usually recognized clinically by looseness

of the implant or the ability to rotate it out of the bone.

• It is sometimes, but not always, associated with pain, which is more

likely to occur when the implant is loaded


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implant failure with purulent discharge and 7.0 mmpocketing. (b) Radiograph of bone loss.


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• Interim treatment will depend upon the superstructure design and

number of implants remaining.

• If there are sufficient implants, and the patient is using a fixed

superstructure, it may be possible to use the prosthesis with a

reduced number of abutments

• A final decision will depend upon the number, length and location of

the implants, the nature of the surrounding bone and the occlusal

loads.


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Biomechanical

Fractures

Screws

• The principle of a screwed joint is put into tension due to its elastic

deformation and that of the clamped components, and thus compresses

the joint.

• This force is known as preload, and maintains the integrity of the joint

provided that the forces which tend to separate the components are less

than the preload.

• Forces above this will open the joint and, if they exceed the plastic limit of

the screw, cause its permanent deformation and loss of joint integrity.

• Excessive tightening of the screw will similarly cause plastic deformation of

the screw, leading to a potentially weaker joint, followed by fracture.


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Screws may fracture for many reasons:

• Overtightening.

• Poorly aligned components.

• Overload.

• Fatigue failure.


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Management

• The first action must be to remove the superstructure and identify

the scope of the damage.

• Following this, the fractured screw should be removed and its

housing assessed for damage.


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Implant body

• Fracture of the implant body is very unusual

and almost invariably occurs as a result of

high occlusal loads or external forces, as for

example in a road traffic accident.

• The only available options in these

circumstances are either to remove the

implant body or, where the remaining

components are deep within the tissues, to

leave it buried.


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PROSTHESIS PROBLEMS

Prosthesis fracture

• loss of a porcelain or acrylic resin facing, or

fracture of the metal substructure itself.

• framework is insufficiently rigid or so large

that it flexes in function to such an extent

that the porcelain/metal interface fails.

• acrylic resin facing, although this material

has a much lower modulus of elasticity

than porcelain and is therefore unlikely to

fracture as a result of substructure flexure.


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• Fracture of fixed and removable prostheses may be caused by:

1. excessive loads

2. fatigue failure

3. substructure flexure

4. poor bonding between the tooth and framework or base

5. inadequate design or construction

6. Bruxism


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Excessive loads

• These can arise from occlusal schemes that place high loads on

individual teeth, for example canine guidance.

• They are also associated with tooth clenching and grinding habits,

and are managed by modified design of the occlusion and

strengthening of the teeth or their occlusal or palatal coverage with

metal where they are made of porcelain or a polymer.


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• Fatigue failure This by definition occurs after extended use,

especially where loads are unduly high, and is best avoided by

designs that minimize the loads on individual teeth.

• Substructure flexure This reflects inadequate design or failure to

recognize the patient who is likely to use high occlusal loads. It

results in high shear stresses at the interface between the tooth and

the substructure, which is therefore more likely to fail.


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• Bond failure Poor bonding between the tooth and the framework or

base results from inadequate construction, whether it be the

bonding of porcelain to an alloy or a polymeric tooth to the

underlying acrylic resin.

• As with other problems tooth fracture is best managed by

avoidance.

• Where this is not practicable then repairs are usually possible,

especially with polymeric teeth.

• The replacement of porcelain is much more expensive as it requires

often extensive refiring.


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Functional problems

Appearance

• Appearance problems related to fixed-implant superstructures are

more common in the upper jaw.

• They are related to the difficulties of placing teeth in the positions of

their natural predecessors

• Where it is desired for the crowns to have the appearance of arising

from the edentulous ridge, the disparity in the preferred positions of

the crown and implant body may be difficult or impossible to

disguise effectively, resulting in an unnatural appearance.

• Bone-grafting procedures can be used to modify the ridge contour


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• 'black triangle' appearance.

• Soft tissues can be the contoured at the

second stage of surgery; however, it is

difficult to achieve a satisfactory result if

there is an excessive gap between the

implants.

• Problems relating to tooth mould, shade

and contour


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Speech

• Speech problems can arise as a result of

changes in the labiopalatal positioning of

the anterior teeth and the level of the

occlusal plane.

• Many of these problems are usually quite

quickly overcome by adaptation

• gap between its framework and the

underlying mucosa- escape of air or

saliva, which can influence the speech


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• Some patients learn to adapt to this situation, while others need to

make use of a removable component to obturate the defect.

• This may consist of an elastomeric bung, which is placed palatally, or

a removable acrylic labial flange.

• It is important when planning implant treatment to inform the

patient in advance if it is thought that speech problems are likely to

occur.


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Mastication

• Masticatory problems when using implant-stabilized bridges are

unusual

• Usually due to the occlusal scheme and nature of the opposing

dentition.

• These can be managed using standard prosthodontic techniques.

• Cheek biting sometimes occurs due to the failure to place maxillary

teeth sufficiently buccally

• Patients must be warned of such potential problems when planning

treatment.


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Conclusion

• Implant therapy has become common practice and will probably

gain in popularity during the next several years.

• This implies that dental professionals will have to deal more with

implant failure and related complications.

• When an implant fails, a tailor made treatment plan should be

provided to each patient according to all relevant variables.

• Patients should be informed regarding all possible treatment

modalities after implant failure and give their consent to the most

appropriate treatment option for them.


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References

• Misch : Contemporary implant dentistry Atlas of implant dentistry,

• 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)

• Yoav Grossmann. Prosthetic treatment for severely misaligned implants: A clinical report. J Prosthet Dent 2002;88:259-6.

• Goodacre C J, Bernal G, Rungcharassaeng K, Kan J Y. Clinical complications with implants and implant prostheses. J ProsthetDent 2003; 90: 121–132.

• Effect of implant size and shape on implant success rates: A Literature review JPD 2005;94:377-81

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complications in impantology