Implant related complications and failures

Basic Terminologies

Purely a histologic term

Osseointegration

used to describe ideal clinical conditions.It should include a time period of at least 12 months for implants serving as prosthetic abutments.

Implant success

implants that remains at the time of evaluation, regardless of any untoward sign and symptoms.

Implant survival

Ten Bruggenkate C, van der Kwast WA, Oosterbeek HS. 1990

Ailing implants are those showing radiographic bone loss without inflammatory signs or mobility.

Ailing implants

Failing implants are characterized by progressive bone loss, signs of inflammation and no mobility.

Failing implants

A failed implant is non-functional and must be removed.

Failed implants

-Meffert

Implant success:A review of past and present concepts• Earlier Concepts• Schnitman and schulman,1979:• Mobility less than 1 mm in any direction.• Bone loss no greater than 1/3of the vertical height of the bone.• Functional service for 5 years.

• Cranin et al.1982:• In place 60 months or more.• No signs of bone loss.• Freedom from hemorrhage.• Lack of mobility.• Absence of pain or percussive tenderness.• No pericervical granulomatosis or gingival hyperplasia.

• McKinney et al. 1984:• Subjective criteria• Adequate function.• Absence of discomfort.• Patient belief that esthetics, emotional, and psychological

attitude are improved.• Objective criteria• Bone loss no greater than one third of the vertical height

of the implant• Gingival inflammation vulnerable to treatment.• Mobility of less than 1 mm buccolingually, mesiodistally,

and vertically.• Success criterion• Provides functional service for 5 years

Era of Revised criteria• Albrektsson et al. 1986• Individual unattached implant that is immobile when tested clinically• Radiography that does not demonstrate evidence of peri-implant radiolucency• Bone loss 1.2 mm after 1 year of service and less than 0.2 mm annually in subsequent years• No persistent pain, discomfort or infection• By these criteria, a success rate of 85% at the end of a 5 year observation period and 80% at the end of a 10 year period are minimum levels for success.

• 1998 Esposito et al. at 1st European Workshop on Periodontology

• The success criteria, which were initially targeted for evaluation as 5 years survival has changed with a target of 10-year survival rate.

“Esthetic” success• The pink esthetic score (PES) is an index proposed

by Furhauser et al that considers 7 soft tissue parameters, including an evaluation of the color, contour, and texture of the surrounding soft tissues (papilla and facial mucosa).

• The most recent, proposed by Belser et al, combines a modified PES index with a white esthetic score (WES)- 5 parameters from general tooth form to hue, value, surface texture, and translucency.

Types of complications1. Surgical2. Biologic3. Mechanical/ technical 4. Esthetic5. Related to augmentation procedure6. Related to loading protocols

Prevalence of Implant Complications• Pjetursson et al found that the most common

technical complication:• fracture of veneers (13.2% after 5 years),• loss of the screw access hole restoration (8.2% after 5

years),• abutment/occlusal screw loosening (5.8% after 5

years), and• abutment/occlusal screw fracture (1.5% after 5 years).• Fracture of implants occurred infrequently (0.4% after

5 years; 1.8% after 10 years).• biologic complications, such as periimplantitis and soft

tissue lesions, occurred in 8.6%

• Goodacre et al. inclusion of edentulous patients having overdentures, seemed to indicate a significantly higher percentage of complications.

• Zitzmann and Berglundh periimplant mucositis- 50% of implant sites.

• Periimplantitis-12% to 43% of implant sites• Esposito et al biologicalfailures were relatively low

at 7.7%.• Risk factors: smoking, diabetes and previous H/o

Periodontitis.

Surgical complication

Surgical complicationsurgicalHaemorrhag

e and hematoma

Neurosensory

disturbancesImplant

malposition

• Problems due to surgical complications are:1. Damage to adjacent teeth2. Impingement on anatomic structures3. Compromised esthetic/prosthetic outcome4. Soft tissue and bone dehiscence

1. Hemorrhage and Hematoma• Lifethreatening may happen with surgical procedure

related to anterior mandible or with perforation lingual mandibular cortex

• In this emergency - primary airway management and surgical management to isolate and stop bleeding

• Caused by drilling or implant compression of the nerve

• Hypoesthesia or hyperesthesia• Most common with “Lateral nerve repositioning”. It is

associated with 100% neurosensory dysfunction and 50% remains permanent

2. Neurosensory disturbance

3. Implant malposition• Common reasons for implant malpositioning are:1. Poor Rx planning2. Lack of surgical skill3. Poor communication between surgeon and

restorative dentist• Ideal position of implant

• To aviod injury to adjacent tooth root, guide pin location radiograph is necessary.

Biologic complications

Biologic complications• Types are:1. Inflammation and proliferation of peri-implant

soft tissue2. Dehiscence and recession3. Peri-implantitis and progressive bone loss4. Implant loss or failure

Inflammation and proliferation

• Similar to plaque induced gingival lesions

• Also common with loose implant-abutment or abutment crown connection and excessive cement retained after restoration.

• Correction of precipitating factors effectively resolves the problem

Dehiscence and recession• Common when the supporting hard and soft

tissues are thin, lacking or lost

Periimplantitis• Lindhe and Meyle from the Consensus Report of

the 6th European Workshop on Periodontology concluded that risk indicators for periimplantitis included

(1) poor oral hygiene,(2) a history of periodontitis,(3) diabetes,(4) cigarette smoking,(5) alcohol consumption, and(6) implant surface

Implant loss or failure• Two types:1. Early implant failure• Occurs before osseointegration. • Osseointegration is jeopardized by infection,

movement or impaired wound healing2. Late implant failure• Occurs after prosthesis installation probably due

to peri-implantitis, progressive bone loss or overload

Mechanical or prosthetic complications

Mechanical or prosthetic complications1. Screw Loosening and Fracture• frequent in screw-retained FPDs• screw loosening in 6% to 49% of cases at the first

annual check-up.- Jemt et al. 1994.• in the patient with a prosthesis retained by

multiple implants, the ability to detect a loose screw is greatly diminished

• biomechanical support (and resistance) for the restoration must be evaluated

• 2. implant fracture• fatigue of implant materials and weakness in

prosthetic design or dimension are the usual causes of implant fractures

• Balshi listed three categories of causes(1) design and material,(2) nonpassive fit of the prosthetic framework, and(3) physiologic or biomechanical overload.

Esthetic and phonetic complications

Esthetic and phonetic complications• The risk for esthetic complications is increased for

patients with high esthetic expectations and less than- optimal patient-related factors (e.g., high smile line, thin periodontal soft tissues, or inadequate bone quantity and quality)

• If the amount of available bone is not ideal… unesthetic emergence profile.

• Benefits of Gingiva colored materials:• Improved lip support• Masking interproximal spaces• Restoration of gingival symmetry

• Phonetic problems:• More common with full arch implant supported prosthesis• Unusual palatal contours• Space between implant and superstructures

Related to augmentation procedures

Related to augmentation procedures1. Complication associated with autogenous bone

harvesting/grafting• At donor site, High incidence of neurosensory

disturbance to mandibular anterior teeth and chin region.

• Inferior alveolar nerve injury or trismus• Recepient site complication, wound dehiscence,

flap necrosis, graft exposure, graft contamination, problem with graft incorporation and resorption

• 2. complications of GBR• Exposure of the barrier membrane and necrosis of

the overlying flap• Simian et al. 2004- 12.5% exposure rate of e-

PTFE.• Other, bone graft infection, failure to regenerate

adequate bone volume, decrease in the depth of vestibule.

Complications associated with sinus augmentation procedure1. Lateral window sinus lift:• Schneiderian membrane perforation or bleeding

from nasal cavity• 20-30% of membrane perforation with

conventional instruments and 7% with piezo surgery- Kasabah 2003

• Infection of the bone graft material placed into sinus in 2-5.6%.

• 2. crestal (osteotome) sinus augmentation• BPPV- benign paroxysmal positional vertigo-

trauma induced by percussion with surgical hammer, along with hyperextension of neck during operation can displace otoliths in the inner ear.

• Prevalence reported 1.25%• in suspected cases, patient is informed about the

condition and referred to the otoneurologist to carry out otolithic reinstatement maneuver

• Prevention using:• Manual force instead of hammer percussion• Surgical fraise/ bur in combination with osteotome• Piezoelectric surgical instuments

Related to placement & loading protocols

Related to placement & loading protocols• 1. immediate implant placement• Poor implant position,• marginal bone loss,• periimplant soft tissue recession,• compromised esthetics,• Failure to attain primary stability and• Implant failure

• 2. immediate loading• failure to achieve primary stability• To avoid complication• long and wide implants• Thread design• for full edentulous arches, mininum 4-6 implants• Cross-arch stabilization• Minimizing cantilever

3. Flapless approach• Complications due to:• Lack of operator visualization• Improper positioning

• It is technique sensitive that requires surgical experience,

• Proper Case selection• an accurate surgical guide and• knowledge of the anatomy surrounding the

implant site

Failure of implants

Signs of failure – Esposito et al.• Signs of infection during healing (6-9 months)• Swelling, fistulas, suppuration, early/late mucosal dehiscences,

and oseteomyelitis• Pain

• Mobility• Dull sound at percussion• Radiographic signs of failure• two well-distinct radiographic pictures:1. A thin peri-fixtural radiolucency surrounding the

entire implant, suggesting the absence of a direct bone-implant contact and possibly a loss of stability

2. an increased marginal bone loss

Factors associated with increased failure rate

Indication for implant removal • Severe peri-implant bone loss (> 50% of implant

length).• Bone loss involving implant vents or holes.• Unfavorable advanced bone defect.• Rapid, severe bone destruction (within 1 yr of

loading).• Nonsurgical or surgical therapy ineffective.• Esthetic area providing implant surface exposure

Summery and conclusion

1. Dental implants have high predictability and long term success but its not “fail free or complication free”

2. Surgical complications can be avoided by proper pre-surgical work ups.

3. Most common prosthetic complications are fracture of veeners, loosening of abutment, screw or prosthesis.

4. Use of torque controlled screwdrivers and implants with internal fixation can reduce the risk of loosening

Tips to avoid complicationsPresurgical diagnosis and Rx planning

No substitute for training and clinical experience for preventing, recognizing and managing complictions

References:1. Fermin A. Carranza, Jr., Michael G. Newman,Textbook of Clinical

periodontology.,1oth ed., WB saunders &Co.,20082. Jan Lindhe, Thorkild Karring . Niklaus P. Lang, Textbook of

Clinical Periodontology and Implant Dentistry, 4th ed. by Blackwell Munksgaard, a Blackwell, Publishing Company, 2003.

3. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: A review and proposed criteria of success. Int J Oral Maxillofac Implants. 1986;1:11–25.

4. Misch CE. Implant Success, Survival, and Failure: The International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent 2008;17:5–15

5. K. Karthik. Evaluation of implant success: A review of past and present concepts. J Pharm Bioallied Sci. 2013 Jun; 5(Suppl 1): S117–S119.

6. Prashanti E. Failures in implants. Indian Journal of Dental Research, 22(3), 2011.

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