Implant failure: multiple factors. Age and sex, smoking, systemic diseases, maxillary implant site, quantity and quality of bone, and implant surface treatments.
Early implant failure- implant mobility before final prosthesis, biological problems, “rejection” of the dental implant. Linked to procedural, poor primary stability, over heating of bone, immunological, genetic, and immunological variables.
Late implant failure- within 1-3 years after implant placement.
Causes of early implant failure: Poor bone quality and quantity, systemic diseases such as uncontrolled diabetes mellitus, AIDS, osteoporosis, medications such as corticosteroids and bisphosphonates, smoking, infection, lack of primary stability, over healing of bone, surgical trauma
Causes late dental implant failure: Excessive loading, peri-implantitis, bruxism, teeth grinding at night time, retained subgingival dental cement, inadequate prosthetic construction, traumatic occlusion
Dental implant failure Local causes
The most frequent and avoidable cause is infection. Peri-implantitis is an inflammatory response with bone loss in the soft tissues surrounding implants. Include plaque-induced, poor biomechanical. Fistulations, mucosal abscesses, and hyperplastic mucositis are other soft tissue problems are mostly infectious. Loose prosthetic components, fistulas and hyperplastic mucositis are frequently observed. Food particles peri-implant crevice can cause abscesses. Implant failures associated with delayed healing influenced by (lack of irrigation and overheating), micromotion, and several local and systemic features of the host. Overload-related implant failures. Poor surgical technique, low bone quality, and poor prosthesis design are additional factors contributing to implant failures.
Management of Local Causes of Implant Failure
Mobility, edema, discomfort, pus, bleeding, and radiographic evidence of peri-implant bone loss. Any obvious mobility, the implant needs to be removed to prevent further alveolar bone loss. Possible treatment options include replacement with a larger diameter implant with a guided bone regeneration (GBR) procedure or a staged approach where the lost tissue is first rebuilt and the implant is then placed following site healing (delayed approach).
Peri-Implantitis
Plaque-associated inflammation in the peri-implant mucosa and consequent gradual bone loss. Bacterial colonization, poor oral hygiene, cements retained in the subgingival area, and microscopic gaps between implant components. Pain around the dental implant area, swollen lymph nodes, an unpleasant taste, bleeding at the gum line, slight movement of the dental implant.
Nonsurgical management of peri-implantitis: first step is mechanical cleaning of the implant surface with curettes of titanium or steel or prophy jets. Local chlorhexidine chips (PerioChips), chlorhexidine lavage/citric acid or powder jet devices, local doxycycline or metronidazole gel, and Ligosan 260 mg (slow-release Ligosan or 12 days direct delivery). Laser decontamination with either CO2 or erbium-yttrium-aluminum-garnet (YAG) laser of 1.5 w frequency. Photodynamic therapy, the photochemical decontamination of peri-implant tissues and the implant surface with a photosensitizer dye in combination with laser light. Ozone therapy. Systemic antibiotics metronidazole 400 mg three times a day (TDS) + amoxicillin 500 mg TDS for seven days or clindamycin 300/600 mg four times a day for seven days.
Surgical management of peri-implantitis: Implants positioned in unsightly locations are removed. Damaged implant debrided with a surgical flap. Surgery using membrane-covered autogenous bone grafts, autogenous bone grafts alone, membranes alone, and a control access flap procedure. Defects treated with membrane-covered autogenous bone grafts had significantly more bone regeneration and re-osseointegration.
Patient who had periodontitis are more likely to get peri-implant illnesses.
Management of Implant Fractures
An osseointegrated implant fracture requires removal of the remaining implant components. If the implant was broken at low level, it may be prudent to leave it, if the implant is adjacent to a critical structure, such as a neurovascular bundle or sinus cavity. Submerged if there are enough implants left to support the prosthesis. If the implant is required to support the prosthesis and no other site can be used, remove it, graft and/or re-entry at a later time.
Fractured implants can be removed by means of trephines. After this, a new implant can be placed at the same time if possible.
Patients with parafunctional should wear occlusal guards. If possible, cantilevers or other unsupported prosthetic extensions should be avoided in the molar areas. Keep an eye out for severe bone loss and recurrent screw-loosening incidents.
Esthetic Complications and Management Due to Implant Malpositions
Proper 3D placement of implants is essential. The three possible directions for implant malposition are mesiodistal, corono-apical, and buccal-lingual. A malposition frequently consists of a variety of faults made in different directions. Implant malpositions can be corrected using the orthodontic bone stretching (OBS) technique, which involves deep partial osteotomies combined with heavy orthodontic forces.
Ensure that the patient is aware of the dangers and esthetic implications of the procedure. Ideal esthetic are frequently impossible because of pre-existing hard and soft tissue defects. The facial bone’s thickness should be 2 mm. Implant should be positioned in the apico-coronal plane (between 2 and 3 mm apical to the predicted mucosal boundary of the implant restoration), mesiodistal plane (at least 1.5 mm away from the roots of adjacent teeth), and buccal lingual plane (at the level of the gingival edge and 1.5 mm lingual to the facial curve of the arch). If it is difficult, a surgical guide stent should be used. In cases where there are numerous lost teeth, surgical stents are strongly advised
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Complications and Management in Guided Bone Regeneration
The most frequent GBR consequence is membrane exposure. Wound dehiscence and membrane or mesh exposure can have a variety of effects, from a minor issue requiring membrane removal and resulting in incomplete bone growth to a major failure and implant loss.
Management: Whether or not a purulent discharge is present, soft tissue dehiscence, will determine management. An exposure smaller than 3 mm without any purulent exudation does not cause any signs or symptoms. If the exposure happens after the fourth month, the device can be maintained in place, 0.2% chlorhexidine gel twice a day. The membrane or mesh needs to be removed right away in cases where the exposure is greater than 3 mm to prevent infection of the regenerating tissue. The flaps should be closed to allow the grafted area to recover for at least 4-5 months if the underlying bone graft is not damaged. To protect the regenerating tissue, the underlying soft tissue must not be lost during removal. Additionally advised is the use of amoxicillin and clavulanic acid for antibiotic coverage. The membrane or mesh must be removed right away if the exposure have purulent discharge to prevent the infection to the underlying regenerating tissue. Then, the graft must be delicately removed to get rid of any infected debris. Augmentin 875 mg of amoxicillin and 125 mg of clavulanic acid twice daily for at least five days.
Give the soft tissue enough time to heal before doing a GBR operation. Prior to surgery, all sources of infection (e.g., periodontally, endodontically, or hopelessly involved teeth) must be eliminated. Apply pre- and postoperative treatment systemic and topical antibiotics.
Implant Removal
Required in severe peri-implantitis, loose dental implants, nerve damage, sinus problems, and loose crowns.
Methods of implant removal: A moveable implant can be easily removed using forceps, the counter-torque ratchet technique (CTRT), or by rotating the implant counterclockwise. The use of elevators, forceps, counter-torque ratchets, screw removal tools, piezo tips, high-speed burs, and trephine burs are a few techniques for removing immobile implants. The least intrusive method for removing an implant without harming neighboring structures is the CTRT. When a fractured implant’s connection is compromised or when the ratchet cannot be engaged to use the CTRT, the reverse screw technique (RST) should be used to remove the implant. To engage the implant, a screw removal device is employed to engage the internal thread and extract the implants using reverse hand torque.
Figure 1
Reverse screw implant retrieval tool
Piezo tips and high-speed burs can be used in conditions where CTRT and RST are not useful to loosen the abutment [43].
Implant failure Systemic causes
One of the key factors in implant failure is age. Older individuals have worse local bone problems and longer possible healing durations and are more susceptible to changing systemic health conditions.
In smokers, the survival rate of dental implants is reduced. Smoking slows down blood flow because of increased peripheral resistance and platelet aggregation, which has an impact on the osseointegration process.
Patients with bruxism experience implant failure more frequently than individuals without parafunction (41% versus 12%).
Diabetes impaired wound healing, and increased susceptibility to infection and periodontal disease, more likely to harm implants in the maxilla, predominance of cancellous bone, than in the anterior jaw, which has an abundance of cortical bone.
Cardiovascular disorders can impact on blood flow to tissues. This impairs blood circulation and lowers oxygen and nutrition levels.
Osteoporosis causes bones to become weak and brittle.
Certain medications: Corticosteroids causes a patient’s immune system to be suppressed, risk of developing osteopenia and osteoporosis. Bisphosphonates inhibiting osteoclast activity. Intravenous bisphosphonates that contain nitrogen and include pamidronate (Aredia) and zoledronate (Zometa), associated with cases of avascular necrosis (osteonecrosis) of the mandible and/or maxilla.
Management of Systemic Causes of Implant Failure
Diabetes: HbA1c levels, to determine how well or poorly the patient is controlled. It is ideal to achieve appropriate glycemic control before implant surgery.
Myocardial infarction: Nitrate premedication, oxygen administration, achievement of profound local anesthesia, stress reduction measures, preoperative pain medication, and patient monitoring of blood pressure and heart rate are preventive measures. Additionally, preserving the patient’s comfort and relaxation may be helped by the use of conscious sedation. Additionally, the dental care provider must be aware of any anticoagulant or thrombolytic treatments being used and comprehend that getting oral implants does not always warrant stopping these treatments.
Osteoporosis: Physiologic calcium (1,500 mg/day) and vitamin D (400-800 IU/day) dosages are advised throughout the postoperative period.
Smoking is a significant risk factor for osteoporosis and implant failure, patients should try to quit smoking and follow a balanced preoperative and postoperative diet. Implant sites should be supplemented before or during implant surgery when there is insufficient bone volume.
To avoid overloading the implant and implant loss, the occlusal load should also be evenly distributed across the dentition.
Corticosteroids: May not be a suitable risk category for implants. Administer steroids until one is certain that collapse is highly unlikely.
Bisphosphonates: Before starting intravenous bisphosphonate medication, a patient should achieve dental stability. Prior to administering intravenous bisphosphonates, healing must be complete if any issue necessitates oral surgery, including the placement of dental implants. Patients who are receiving intravenous bisphosphonates for asymptomatic conditions should practice adequate oral hygiene and dental care to avoid dentoalveolar surgery. Direct osseous damage procedures are to be avoided. Dental implant placement should be avoided in oncology patients who have received numerous doses of the more strong intravenous treatment (4-12 times per year). Surgery is not prohibited while oral bisphosphonates are taken, but the dental professional must proceed with caution.