It is essential for practitioners who place dental implants to be able to diagnose and treat common complications or know when to refer to a specialist. Common complications can include nerve injuries, infections, sinus membrane perforations, and edema. This article discusses these complications, incidence rates, tips to avoid common complications, and management options when a patient returns with a complication.
Key points
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Postimplant surgery complications are common.
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Nerve injuries should be identified and diagnosed based on degree of injury.
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Routine implants do not need antibiotics unless patient returns with an infection.
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Sinusitis first-line antibiotic is amoxicillin with or without clavulanate.
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Ibuprofen and dexamethasone can reduce postoperative edema and discomfort.
Introduction
The introduction of implants has revolutionized restorative and surgical dentistry. With the evolution of technology, implants have become more affordable, become smaller, and come with different surface types and shapes. However, even with these technological advances, knowledge of the anatomy, surgical skill, and management of common complications are of upmost importance. Postimplant placement complications can be separated into 2 categories: early failure or late failure. Early failure usually is within the first 6 months or before osseointegration, whereas late failures are after the first 6 months or during the restorative phase. , Primary predictors of implant failure include poor bone quality, chronic periodontitis, systemic diseases, smoking, advanced age, implant location, parafunctional habits, loss of implant integration, and inappropriate prosthesis. This article discusses common postimplant surgery failures and management of these complications.
Neurosensory disturbances and nerve injury
Neurosensory disturbances throughout the maxillofacial region can occur because of trauma, neoplasms, infections, or secondary to a surgical procedure. Two common neurosensory injury classification systems are Seddon and Sunderland. The classifications systems are explained in Table 1 .
| Injury Type | Extent of Injury | Recovery Time | Surgical Treatment |
|---|---|---|---|
| Sunderland 1stdegree (Seddon neuropraxia) | Transient ischemia, anoxia, ± segmental demyelination, intrafascicular edema causing block of conduction | Fast: hours to weeks | None indicated |
| Sunderland 2nd degree (Seddon axonotmesis) | Axon and myelin interruption (intact endoneurium, perineurium, and epineurium) | Slow: weeks Regeneration rate 1–3 mm/d |
None indicated |
| Sunderland 3rd degree | Injury involves endoneurium (intact perineurium and epineurium) | Slow: weeks to months | Nerve exploration can be considered |
| Sunderland 4th degree | Injury involves endoneurium and perineurium (intact epineurium) | Spontaneous recovery not likely | Microneurosurgery |
| Sunderland 5th degree (Seddon neurotmesis) | Complete nerve transection, continuity disruption | Spontaneous recovery not possible | Microneurosurgery |
A review of published literature reveals studies investigating the incidence of injury are inconsistent. Published articles of nerve injury from implant placement range between 0% and 13% with some reporting incidence rates as high as 40%. , These inconsistencies are primarily due to interchangeable definitions of nerve injury and evaluation. Neurosensory disturbances can be permanent or transient. Patients usually suffer varying degrees of the following symptoms: numbness to teeth, chin, cheeks, and lips, speech impediments, problems with speech and mastication, inability to control food and liquid with unintended drooling, and occasionally, chronic pain.
Nerve damage is more likely to occur when placing dental implants in the mandible. As bone resorption occurs in the mandible, the distance from the alveolar crest to the inferior alveolar nerve and mental nerve decreases, consequently increasing the chance of accidental nerve injury. Nerve damage after implant surgery is mainly caused by direct or indirect injury from osteotomy drilling or implant placement, stretching of the nerve caused by excess traction of the flap, or direct needle injury. Postoperative edema can be another cause of paresthesia; however, this usually will resolve once the edema subsides. The most common areas to be affected are the lower lip and chin region; although unlikely, but still possible, are the tongue, palate, and localized tissues.
In order to avoid nerve injuries, the practitioner should always refer to radiographic imaging before implant placement. If 3-dimensional imaging is available, this is far superior to traditional 2-dimensional imaging. If only 2-dimensional imaging is available, using a radiographic marker will help calibrate any digital measurements and reduce the margin of error for inaccuracies. Using available software to map and highlight the nerve will always help plan for accurate placement as well as using implant planning software. Another important factor to consider is the length of each implant drills. Traditionally, implant drills have measurement markings to denote the depth within the bone. However, the start and stop point of these measurements may vary from manufacturer to manufacturer. There can be an additional 0.5 to 2 mm at the tip of the drill from the indicator line. It is crucial to read your implant manufacturer’s catalog or contact the representative to understand the exact length and where the depth measurements are taken from. Another way to ensure proper depth management is by taking intraoperative radiographs. These radiographs will help the clinician know where he or she is within the bone. Another way to avoid nerve damage is to control flap retraction. Overreflection of a flap, especially in the area of the mental nerve, can cause stretching and transient neurosensory disturbances, and always place retractors on bone, not the soft tissue.
If a postoperative patient is noted to have a neurosensory injury, the first important step is early identification and diagnosis of the degree of injury. Subsequently, management is based upon mechanism, location, and degree of injury. An injury from overretraction of a flap (Seddon neuropraxia, Sunderland first degree) could completely resolve on its own or with adjunctive pharmacologic therapy. If a crush injury is suspected directly from an implant, similar to Fig. 1 , then the implant should be backed out immediately or removed completely. In addition, pharmacologic therapy should also be initiated with close monitoring of the patient. Subjective findings the patient may share should be documented, but objective findings should also be noted. Baseline testing should include testing for touch with von Frey hairs, 2-point discrimination with a Boley gauge or similar, temperature, and taste (if involvement of lingual nerve is suspected). Evaluations should be completed every 3 weeks postoperatively to assess for changes in the patient’s condition. If the patient has persistent anesthesia at 6 to 9 weeks, microneurosurgery should be considered, and appropriate referrals given to the patient in a timely fashion.
Preoperative antibiotics and postoperative infections
The routine use of prophylactic antibiotics in implant dentistry seems to be widespread. However, the use of preoperative, perioperative, and postoperative antibiotics in dental implant surgery remains controversial. A search of the literature can show postoperative infections as high as 5.9% to 11.5% with antibiotics and as low as 7.0% without antibiotics. According to Mazzocchi and colleagues, apart from individuals suffering from systemic diseases, most patients undergoing dental implant surgery are healthy individuals who do need antibiotics for small surgical wounds. A study published in the Journal of Hospital Infection reported there was some evidence that 2 g of amoxicillin given 1 hour preoperatively reduced early failures of dental implants, although further research was needed to confirm the findings.
The 2 most common types of dental implant-associated infections are peri-implant mucositis and peri-implantitis. Peri-implant mucositis is inflammation confined to the soft tissues surrounding an implant without signs of bone loss following normal bone remodeling. Peri-implantitis is an inflammatory process that affects both the soft tissue and the bone surrounding an implant beyond what is biologically expected ( Fig. 2 ). Table 2 outlines the distinctions between the two.
