Dental implants
Risks and complications

Last Updated: 10.01.2024

Author: George Ghidrai, MD  

Even though enormous technical advances have significantly improved the quality of dental treatments, accidents and complications may still occur, and it is vital to be aware of this.

The placement of dental implants is a surgical procedure and carries the usual risks of surgery. Other complications may occur in the first 6 months after the placement and even in the long-term.

1. Risks and complications during implant surgery

Placement of dental implants is a surgical procedure and carries the usual risks of surgery. If additional surgical procedures are performed (sinus lift, bone graft, etc.), they also have the normal risks.

However, the risk of complications is considered to be very low - less than 5 percent, according to current statistics. Problems are rare, and when they do occur, they are usually minor and easily treated.

• Bleeding

  Life-threatening events associated with dental implants are extremely rare, but some severe bleeding may occur, especially if large blood vessels are injured during surgery.

  If such an accident should occur, treatment includes compression, vasoconstrictive medication, cautery, or ligation of arteries. Most of the time, bleeding is kept under control.

  
  

• Infection

  Infection from bacteria is a common risk to any surgery. In modern days, less than 1% of surgeries result in an infection, and most of those infections are minor.

  An infection at the implant site during surgery or in the early days after surgery can increase the risk of implant failure. Pre-op antibiotics reduce the risk of implant failure but have little impact on the risk of infection.

  Proper oral hygiene after surgery is essential. A clean mouth will heal faster, and the risk of infection is reduced if the mouth is not riddled with bacteria and food debris.

  
  

• Nerve damage

  The most common issue is when the inferior alveolar nerve (located inside the mandible) is accidentally damaged during surgery. After surgery, patients may experience lingering pain, tingling, and numbness in the teeth, gums, lips (mainly the lower lip), or chin for an undetermined time.

  

  important anatomical structures
  that can be damaged during implant surgery

  If the nerve damage is minor, patients will likely recover.

  
  

• Sinus problems

  Sinus problems occur when dental implants placed in the upper jaw protrude into one of the sinus cavities. Careful planning and precise surgery execution are essential to avoid this accident.

  

  panoramic film: a dental implant protrudes into the sinus cavity

  Even if sinus complications do not occur in every case, these implants have a high risk of failure because of insufficient bone support.

  
  

• Lack of stability

  An inability to place the implant in the bone to provide stability (referred to as primary stability) increases the risk of failure to osseointegration.

  Some research even suggests that the primary stability of the implant in bone is a more critical determinant of the success of implant integration rather than a certain period of healing time.

  
  

• Other risks

  Other accidents may occur during the surgical placement; these are extremely rare: damage (and possible devitalization) of adjacent teeth or other surrounding structures, necrosis of the flap of tissue around the implant, or mandibular fracture.

2. Risks and complications in the first 6 months

These complications occur in the first 6 months after implant placement. The most common complication is the failure to integrate.

• Failure to integrate

  An implant failure to integrate in the first 6 months can first be related to some general or local factors :

  • general conditions such as uncontrolled diabetes, untreated osteoporosis, radiation exposure on the head and neck, or other severe conditions
  • improper oral hygiene
  • heavy smokers or high alcohol consumption
  • various accidents during surgery: infection, puncture of a sinus cavity, etc

  However, the latest research suggests that primary implant stability is the principal factor.

  For this, an implant needs to be surrounded by a healthy quantity of bone, and it has to be placed in the bone to provide stability for the implant. Loosening implant posts have a higher risk of failure.

  An implant is tested between 8 and 24 weeks to determine bone integration. The clinical signs to determine implant success are the absence of pain, mobility, infection, and gingival bleeding.

  The osseointegration status is then tested on radiographs and with specific devices (e.g., Periotest).

  

  dental X-ray: implant failure to integrate; it is considered that
  a radiographic lucency greater than 1.5 mm around a dental implant is a sign of failure

  What is Radiographic Lucency?

  • In radiology, lucency is a darker region normally caused by soft tissues, air, or liquid.

    It is the opposite of opacity, which has a whiter shade and is caused by hard tissues (teeth, bone), metal, or artifacts. Lucency around a dental implant signifies bone loss.

  
  

  While there is significant variation in the rate at which implants fail to integrate (due to individual risk factors), the approximate values are 1 to 6 percent.

3. Long term complications

Long-term implant failures may be caused by an improper design of the prosthetic restoration or by inappropriate care and maintenance. Regardless of the cause, implants fail due to either loss of bone around them or a mechanical failure of the implant.

There are also the risks associated with the prosthetic components, which, over time, can wear off, chip, break, or cause a lack of satisfaction on the part of the patient.

• Peri-implantitis

  Peri-implantitis is a destructive inflammatory process affecting the soft and hard tissues surrounding an osseointegrated implant in function. Peri-implantitis is an infectious disease; various factors can cause this condition:

  • improper oral hygiene
  • excessive mechanical load on the implant
  • the status of the tissue surrounding the implant
  • patients with diabetes
  • heavy smokers

  Diagnosis is based on changes of color in the gingiva, bleeding, and probing depth of peri-implant pockets and suppuration. The X-ray shows a gradual loss of bone height around the implant.

  

  peri-implantitis

  If peri-implantitis is diagnosed, treatment will depend on the amount of bone loss and the aesthetic impact of the implant in question.

  The therapeutic approach can range from local debridements around the implant fixture, antibiotics, antiseptics, and ultrasonic and laser treatments to regenerative procedures using a bone graft.

  
  

• Fracture of the implant

  The fracture is a mechanical failure of the implant. Fractures may occur when implants are too short or too thin. The implant can fracture at various levels :

  • The fracture of the implant and abutment screw is a catastrophic failure, and usually, the fixture and the prosthetic components cannot be salvaged (image a).

  • When only the abutment fractures, the abutment and the crown would need replacement, but the implant fixture can sometimes be salvaged (image b).

  

  a: fracture of the implant

  

  b: fracture of the abutment screws

  
  

• Gingival recession

  The most common cause of gingival recession is gingivitis, an inflammatory disease of the gums mainly caused by improper oral hygiene.

  Recession of the gingiva leads to exposure of the metal abutment under a dental crown. In other situations, black triangles caused by bone loss and the retraction of the papilla appear between implants and natural teeth.

  

  gingival recession

  

  black triangles

  Some of these conditions may be improved with a soft tissue graft. Before any surgery, all causative agents have to be removed.

  
  

• Prosthetic restoration risks

  Besides the implants, there are risks associated with the prosthetic components.

  First, poor aesthetics, including a high smile line, poor gingival quality, and missing papillae, plus the difficulty in matching the form and shade of natural teeth, may lead to a lack of satisfaction on the part of the patient (assuming the patient does not have unrealistic expectations).

  Over time, prostheses can wear off, chip, break, detach, change aesthetic appearance, or suffer other complications.

  

  chipped porcelain restoration

  Most of the time, the implant fixtures last longer than the prosthesis. The lifespan for a prosthetic reconstruction is around 15 years, while a well-positioned implant fixture can last a lifetime.

  Additionally, removable dentures and overdentures need regular maintenance.

Patients who wear implant-supported prostheses should ideally be free of pain or any other unpleasant signs, able to chew and taste, and pleased with the aesthetics.

Implants should be tested at least twice a year during regular checkups. Criteria for the success are:

• the absence of pain
• the absence of mobility
• no radiographic lucency greater than 1.5 mm around implants
• the lack of suppuration or bleeding in the soft tissues
• adequate function and aesthetics in the prosthetic