This document discusses various complications that can occur with dental implants. It begins by defining implant survival and success. It then discusses the prevalence of implant complications and lists some common risk factors. The document is organized by type of complication, including surgical (e.g. hemorrhage, nerve damage), biologic (e.g. inflammation, bone loss), prosthetic/mechanical (e.g. screw loosening, fracture), and esthetic complications. For each complication, contributing factors and examples are provided. The conclusion reiterates that complications can usually be prevented through careful treatment planning, surgical skill, and maintenance of implant hygiene.

1. S OF ICOMPLICATIONS
OF DENTAL IMPLANT
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2. CONTENTS
• Definition of Implant survival and Implant success
• Prevalence of Implant complications
• Surgical Complications
• Biologic Complications
• Prosthetic or Mechanical Complications
• Esthetic or Phonetic Complications
• Conclusion
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3. DEFINITION OF IMPLANT SURVIVAL AND
IMPLANT SUCCESS
• Implant survival is simply defined as any implant that remains in
place at the time of evaluation, regardless of any untoward signs,
symptoms, or history of problems.
• Implant success, conversely, is defined not only by the presence
of the implant but also by criteria evaluating the condition and
function of the implant at the time of examination.
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4. • In the classic definition, Albrektsson et al defined implant success
as an implant with no pain, no mobility, no radiolucent
periimplant areas, and no more than 0.2 mm of bone loss annually
following the first year of loading.
• Roos-Jansaker et al added to this definition by defining a
successful implant as one that lost no more than 1 mm of bone
during the first year in function.
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5. PREVALENCE OF IMPLANT
COMPLICATIONS
• The prevalence of implant-related complications has been reported in
several reviews.
• However, until recently, a systematic review of the incidence of
biological and technical complications in studies of at least 5 years
revealed that biological complications were considered in only 40%
to 60% and technical complications in only 60% to 80% of the
studies.
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6. • Risk factors, such as smoking, diabetes, and periodontal disease,
may contribute to implant failure and complications.
• Several studies with numerous implants and years of follow-up
have concluded that smoking is a definite risk factor for implant
survival.
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7. SURGICAL COMPLICATIONS
Proper precautions must be taken to prevent the risk of injury resulting
from surgical procedures, including but not limited to
(1) a thorough review of the patient’s past medical history,
(2) a comprehensive clinical and radiographic examination, and
(3) good surgical techniques.
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8. • Surgical complications include perilous bleeding, damage to
adjacent teeth, injury to nerves, and iatrogenic jaw fracture.
• Postoperative complications include bleeding, hematoma, and
infection.
• They may be minor, transient, and easily managed or more serious
and require postoperative treatment.
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9. HEMORRHAGE AND HEMATOMA
• Bleeding during surgery is expected and usually easily controlled.
However, if a sizable vessel is incised or otherwise injured during
surgery, it can be difficult to control.
• This can be especially difficult if there is a vascular injury to an
artery that is inaccessible such as in the floor of the mouth or
posterior maxilla.
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10. • Serious bleeding from an inaccessible vessel can be life
threatening, as a result of airway obstruction.
• This is most problematic when the point of bleeding is
inaccessible and internal (within the connective tissues and soft-
tissue spaces).
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11. Clinical photograph of postoperative bleeding around healing abutments after
second-stage implant exposure surgery. 12/18/2020 11

12. Clinical photograph of postoperative (extraoral) bruising indicative of subdermal
bleeding into connective tissues spaces. This is a normal expectation that resolves
within 7 to 14 days
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13. • Emergency treatment includes airway management (primary
importance) and surgical intervention to isolate and stop the
bleeding.
• Clinicians must be aware of this risk and must be prepared to act
quickly.
• It is important to recognize that bleeding, although considered a
complication at the time of surgery, may be a serious
complication in the hours and days after surgery.
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14. NEUROSENSORY DISTURBANCES
• Neurosensory alterations is caused by damage to a nerve which may
be temporary or permanent.
• Neuropathy can be caused by a drilling injury (cut, tear, or puncture
of the nerve) or by implant compression or damage to the nerve .
• In either case, the injury produces neuroma formation, and two
patterns of clinical neuropathy may follow.
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15. • Hypoesthesia is a neuropathy defined by impaired sensory
function that is sometimes associated with phantom pain.
• Hyperesthesia is a neuropathy defined by the presence of pain
phenomena with minimal or no sensory impairment. .
• It is likely that neurosensory disturbances occur more frequently
after implant surgery than currently reported in the literature for
several reasons.
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16. • First, many of these changes are transient in nature, and most patients
recover completely or at least recover to a level that is below a threshold
of annoyance or daily perception.
• Second, wide variation exists in the postoperative evaluation of patients
by clinicians. Some clinicians do not examine or inquire about
postsurgical neurosensory disturbances at all, thus allowing this
complication to go unnoticed.
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17. A : Cross-sectional image from CT scan showing implant impinging on inferior alveolar nerve
canal. B: Panoramic image of CT scan showing implant in lower left first molar area impinging on
inferior alveolar nerve canal. Nerve is marked by tracing with software.
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18. IMPLANT MALPOSITION
• Many of the mentioned complications that arise during implant
surgery can be attributed to the dental implant being placed in an
undesired or unintended position.
• Malpositioning of dental implants is usually the result of poor
treatment planning before the implant surgery, lack of surgical skill
by the implant surgeon, and/or poor communication between implant
surgeon and restorative dentist .
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19. • The ideal implant position entails an accurate preparation,
insertion, and placement of the implant into the alveolus in a
proper three-dimensional geometry according to apicocoronal,
mesiodistal, and buccolingual parameters, as well as implant
angulation relative to the final prosthetic restoration and gingival
margin.
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20. • Apicocoronally, the implant should be placed so that the dental implant platform
is 2 to 3 mm apical to the gingival margin of the anticipated restoration.
• Mesiodistal implants should be placed at a distance of 1.5 to 2 mm from a natural
tooth and 2 to 3 mm from an adjacent implant to maintain an adequate biologic
dimension.
• Ideally, implants should be placed, buccolingually so there is at least 2 mm of
bone circumferentially around the implant.
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21. Radiograph of two mandibular anterior implants placed too close
together (no proximal space) resulting in implants that will be
impossible to restore. 12/18/2020 21

22. • In most anterior cases, it is desirable to have the implant long axis
directed so it is emerging toward the cingulum.
• In the posterior region, the implant axis should be directed toward
the central fossa or the stamp cusp of the opposing tooth.
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23. • Particular care must be taken when placing implants in the
mandible so as to not encroach on the inferior alveolar canal or
the mental foramen.
• In the maxilla, care must be taken to avoid dental implant
perforation into the maxillary sinus or nasal cavity.
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24. Clinical photograph of maxillary anterior implant (left central incisor) placed with an extreme
facial angulation resulting in an implant that emerges through the gingiva at a level that is more
apical than the adjacent natural tooth gingival margins. A, Surgical exposure of malpositioned
implant. B, Surgically removed implant. C, Alveolar defect resulting from surgical removal of
malpositioned implant.
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25. • The ultimate complication of malposed implant is instrument invasion into vital
structures.
• Three-dimensional imaging (e.g., computed tomography [CT] and cone-beam
CT [CBCT] scans) provides the surgeon with useful presurgical information for
proper diagnosis and treatment planning .
• Careful surgical exposure for direct visualization and identification of the mental
nerve may be indicated as well. Once identified, it is recommended to establish a
“zone of safety” and to keep instrumentation and implants a safe margin away
from the nerve.
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26. BIOLOGIC COMPLICATIONS
Biologic complications involve pathology of the surrounding peri-
implant hard and soft tissues.
Frequently, soft-tissue problems are an inflammatory response to
bacterial accumulation. The cause of bacterial accumulation around
implants is key to understanding the problem.
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27. INFLAMMATION AND
PROLIFERATION
• Inflammation in the periimplant soft tissues has been found to be
similar to the inflammatory response in gingival and other
periodontal tissues. Not surprisingly, the clinical appearance is
similar as well.
• Inflamed periimplant tissues demonstrate the same erythema,
edema, and swelling seen around teeth.
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28. Inflammatory proliferation caused by a loose-fitting connection between the
abutment and the implant
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29. A, Clinical photograph of abscess caused by excess cement trapped
within the soft tissues. B, Radiograph of implant with cemented
crown (same patient as in A).
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30. Fistula caused by loose implant-abutment connection (maxillary
left lateral incisor).
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31. DEHISCENCE AND RECESSION
• Dehiscence or recession of the periimplant soft tissues occurs when
support for those tissues is lacking or has been lost.
• Recession is a common finding after implant restoration and should
be anticipated especially when soft tissues are thin and not well
supported .
• Improper implant positioning also predisposes periimplant tissues to
recession.
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32. • As noted earlier, placement or angulation of the implant too far
to the buccal causes the buccal plate to resorb and has been
shown to result in greater recession.
• Another factor to consider is the thickness of the buccal plate of
bone.
• Spray et al recommended this thickness to be 2 mm or greater to
support the buccal soft tissue.
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33. • If this thickness is not present, presurgical or simultaneous site
development using guided bone regeneration is indicated.
• Recession is a problem that is particularly disconcerting in anterior
esthetic areas.
• Patients with a high smile line or high esthetic demands consider
such recession a failure .
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34. A, Clinical photograph of single-tooth implant crown (maxillary right central) with moderate
recession that occurred 1 year after delivery of final restoration. B, Radiograph of wide-diameter
(6 mm) implant supporting maxillary central incisor crown (same patient as in A).
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35. Poor esthetics resulting from gingival recession and exposure of crown margins, implant
collars, and threads of several maxillary and mandibular implants supporting full-arch
fixed partial dentures (FPDs). Notice the thin labial tissues and erythema (especially
around mandibular implant sites)
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36. PERIIMPLANTITIS AND BONE LOSS
• Periimplantitis can be defined as an inflammatory process
affecting the tissues around an osseointegrated implant in
function, resulting in loss of supporting bone.
• Standarized radiograph techniques , with or without computerized
analysis have been well documented and found to be useful in
evaluating periimplant bone levels.
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37. • Clinicians should monitor the surrounding tissues for signs of
periimplant disease by monitoring changes in probing depth and
radiographic evidence of bone destruction, suppuration, calculus
build up , swelling , color changes and bleeding.
• A classic trough-type defect is typically associated with
periimplantitis.
• In cases with severely reduced bony support extending into the
apical half of the implant or in cases demonstrating mobility
implant removal should be considered.
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38. uModerately advanced bone loss around an implant with the
typical circumferential trough type of bony defect 12/18/2020 38

39. Severe horizontal and vertical bone loss around several mandibular implants
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40. • RISK INDICATORS OF PERIIMPLANTITIS ACCORDING TO RECENT
REVIEW BY LINDHE AND MEYLE FROM THE CONSENSUS REPORT OF
THE SIXTH EUROPEAN WORKSHOP ON PERIODONTOLOGY :
 Poor oral hygiene
History of periodontitis
Diabetes
Cigarette smoking
Alcohol consumption
Implant surface
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41. IIMPLANT LOSS OR FAILURE
• Implant loss or failure is generally considered relative to the time of
placement or restoration.
• When an implant fails before restoration (i.e Early implant failure ) , it
probably did not achieve osseointegration , or the integration was weak or
jeopardized by infection, movement or impaired wound healing.
• Late implant failure occur after prosthesis installation for a variety of reasons
including infection and implant overload.
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42. 12/18/2020 42

43. Four unit fixed partial denture in the posterior maxilla supported by only two implants
A)Clinical photograph of implant abutments in posterior maxilla
B)Radiograph taken 30 months after restoration . Note the bone loss around distal
implant
C) Failed distal implant attached to failed prosthesis.
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44. PROSTHETIC OR MECHANICAL
COMPLICATIONS
• Prosthetic or mechanical complications occur when the strength of
materials is no longer able to resist the forces that are being
applied.
• As materials fatique , they begin to stretch and bend ; ultimately
depending on the applied forces , they will fracture .
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45. SCREW LOOSENING AND FRACTURE
• Screw loosening has been reported to occur quite frequently in
screw retained FPDs .
• Screw retained single crowns attached to externally hexed
implants are particularly prone to this type of mechanical
complication.
• Studies have reported screw loosening in 6 to 49% of cases at first
annual check up.
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46. • Abutment or screw loosening is often corrected by retightening the
screw .
• If screw continues to be stretched they become fatique & eventually
fracture.
• Newer abutment designs & improved abutment screws allows for an
increased clamping force to be achieved without excessive torque
level, which has helped to reduce the rate of screw loosening .
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47. IMPLANT FRACTURE
• The ultimate mechanical failure is implant fracture because it
results in loss of the implants and possibly the prosthesis.
• Removal of fractured implant creates a large osseous defect.
• Factors such as fatique of implant materials and weakness in
prosthetic designs or dimension are usual causes of implant
fracture.
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48. A)Radiograph of fractured implant used to support a molar sized single
crown in the posterior mandible
B)Crown and coronal portion of implant (same as A ) that fractured
between the third and fourth threads
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49. • Balshi listed three categories of causes that may explain implant
fractures : 1) design and material, 2) non passive fit of the
prosthetic framework , 3) physiological or biomechanical
overload.
• Patients with bruxism seem to be at higher risk for such events
and therefore need to be screened , informed & managed
accordingly with occlusal guards.
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50. FRACTURE OF RESTORATIVE
MATERIALS
• Fracture or failure of materials used for implant retained
restorations can be a significant problem.
• This is particularly true for veneers that are attached to super
structures .
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51. 12/18/2020 51

52. ESTHETIC COMPLICATIONS
• The challenge of modern dentistry is achieving an esthetic , as well
as functional implant restoration .
• Patient satisfaction with the esthetic outcome of the implant
prosthesis vary from patient to patient , depending on a number of
factors.
• Esthetic complications result from poor implant position and
deficiencies in the existing anatomy of the edentulous sites that were
reconstructed with implants.
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53. • Implant placement in the esthetic zone requires precise three
dimensional tissue reconstruction and ideal implant placement .
• If the amount of available bone does not allow for ideal implant
placement and if the implant is positioned too apical , buccal or in
the proximal space , an unesthetic prosthetic profile will be
developed.
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54. • If crown contours and dimensions are not ideal, or if gingival
harmony around the implant restoration is unesthetic , the patient
may consider the implants or restorations as complications because
the outcome does not represent a natural appearance.
• If the patient is truly dissatisfied with the esthetic result and there is
the problem with the position of the implants that can be corrected ,
the implants should be removed & possibly retreated .
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55. “
”
HIGH GINGIVAL MARGIN ON SINGLE TOOTH IMPLANT CROWN IN THE
MAXILLARY LATERAL INCISOR POSITION . NOTE THE DISCREPANCY
BETWEEN GINGIVAL MARGINS LEVELS OF THE IMPLANT AND THE
ADJACENT NATURAL TEETH 12/18/2020 55

56. “
”
PINK PORCELAIN USED ON IMPLANT – SUPPORTED FIXED RESTORATION
TO MASK THE HIGH GINGIVAL MARGIN AND LONG IMPLANT CROWNS
RESULTING FROM AN UNCORRECTED ALVEOLAR RIDGE DEFECT12/18/2020 56

57. • Clinician should consider prosthetic solutions before implant
removal.
• Use of angulated abutments , superstructures and gingiva colored
materials may result in acceptable esthetic results .
• Careful patient evaluation and treatment planning along with a solid
understanding & appreciation for the predictability & limitation of
implant procedures will minimize esthetic complications.
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58. PHONETIC PROBLEMS
• Implants prostheses that are fabricated with unusual palatal contours or that
have spaces under and around the superstructure can create phonetic
problems.
• These patients are probably best served with an implant – assisted maxillary
overdenture because the design facilitates replacement of missing alveolar
structure and avoids creating spaces that allow air to escape during speech.
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59. CONCLUSION
• Careful diagnosis & treatment planning, along with the use of
diagnostic imaging, surgical guides , meticulous techniques and
adherence to proven principles can prevent many problems
discussed in this presentation.
• A thorough understanding of anatomy , biology & wound healing
can reduce the incidence of complications.
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60. REFERENCES
 CARRANZA’S CLINICAL PERIODONTOLOGY
( 11TH EDITION )
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