sinus with bone grafting at the same time if another implant is planned in the future in that same site. In rare clinical situations, when a surgeon places a pterygoid implant, the implant can become displaced into the pterygomaxillary or infratemporal fossae. The two known causes leading to this complication are poor primary implant stability and inappropriate surgical techniques usually by using a wider diameter implant and an incorrect inclination of the pterygoid implant during its insertion. A CT‐guided endoscopic removal of a dental implant, whereby the endoscope can be passed through the nasal cavity into the maxillary sinus, terminating into the pterygomaxillary fossa, may be used for implant retrieval. A displaced implant in the infratemporal fossa can be removed preferentially via an intraoral maxillary posterior vestibular approach or a pre‐auricular with hemicoronal approach, if necessary for an implant in a location inaccessible from a transoral approach. In an attempted implant retrieval procedure, further implant displacement can occur, making the process more challenging. Therefore, a waiting period of three to six weeks to allow for adequate fibrosis to occur around the implant in order to stabilize its location may help to facilitate its removal [24, 25]. In these cases, 3D imaging should be used to locate the implant precisely in the soft tissues, and it is possible that CT guidance with needle localization may be required if the implant is in a location that is difficult to access.
Fig. 3.8. Implant displacement into the left maxillary sinus.
Fig. 3.9. Implant displacement into the right maxillary sinus.
Dental implant displacement can occur not only during a maxillary implant procedure but also during mandibular implant surgery. Involvement of anatomical spaces such as the sublingual and submandibular spaces during implant placement is an uncommon complication. There have been few case reports in the literature for each location, and, in these cases, the implants reportedly migrated to those spaces in a delayed fashion. Poor implant positioning, lack of primary implant stability, violation or resorption of the lingual cortex primarily due to peri‐implantitis, and fracture of the lingual cortex during implant placement are all some reported causes of these complications [26, 27]. Once recognized, a CT scan is used to locate and plan for implant removal. If the displaced implant is present in the sublingual space, an intraoral approach can be utilized, whereas an extraoral approach should be used to access the submandibular space, especially if the implant is not palpable intraorally in the floor of the mouth. Lastly, overdrilling of the osteotomy site with a lack of primary implant stability, and presence of a focal osteoporotic bone marrow defect, can lead to implant displacement into the IAC or the porous marrow of the mandibular body, as discussed previously [28]. After performing a CBCT scan, the implant removal should be achieved via an osteotomy through an intraoral approach (Algorithm 3.3).
Algorithm 3.3: Implant Displacement and Migration
Dental Implant Aspiration
Aspiration of a dental implant or implant components is one of the possible complications during implant placement. Coughing, choking, wheezing, and hoarseness, chest pain, and shortness of breath are the signs and symptoms of respiratory distress secondary to aspiration, and this represents a medical emergency. In such cases, basic life support should begin immediately, and patient monitors should be applied including noninvasive blood pressure monitoring, pulse oximetry, three‐lead electrocardiogram, end‐tidal carbon dioxide monitoring, and supplemental oxygen; endotracheal intubation could be considered to secure the airway in extreme circumstances. Some authors have described the use of simple finger sweep technique to remove the aspirated material, but only if the implant or foreign body is visible in the oral cavity, or else further displacement into the airway may result. If accidental ingestion is suspected, the Heimlich maneuver should be performed and the patient should be placed on supplemental oxygen, if necessary. If an aspirated implant or implant component can be visualized, an attempt at removal can be made with the use of Magill forceps and laryngoscope. If there is a decline in oxygen saturation, endotracheal intubation or emergent surgical cricothyroidotomy may be indicated [29]. In most cases of aspiration, the foreign body (dental implant) becomes lodged in the right mainstem bronchus due to the more vertical course from the trachea, as well as its greater diameter compared to the left mainstem bronchus. A chest X‐ray must be obtained to confirm the location of an aspirated object, and this will likely include a visit to the Emergency Department. Once confirmed that the implant has been aspirated, appropriate consultations should occur with respiratory therapy or pulmonology and bronchoscopy should be carried out urgently to retrieve the implant.
Dental Implant Ingestion
Ingestion of a dental implant or implant component can pose several concerns. Due to their small size, implants and components are smaller than coins, and usually do not become lodged in the esophagus; most often, they are found in the stomach on radiographs and then move on through the digestive tract without incident; most of the time (90%), the ingested foreign object passes through the gastrointestinal (GI) tract without complications, and they also rarely become lodged at the ileocecal valve. About 10% of the time, an endoscopic retrieval may be required if the implant does not move completely through the GI tract spontaneously. Although most data show that small and blunt objects pass through the GI tract uneventfully, it is estimated that in 1% of cases a GI surgical procedure is required to retrieve an ingested object [29]. A conservative approach to this complication should include a clinical abdominal examination, obtaining abdominal X‐rays, and timely stool inspection for documentation that the implant has passed. Perforation within the GI tract is rare, but more likely to occur with sharp foreign objects, and this warrants a referral to a gastroenterologist for an early open or endoscopic assessment of the GI tract and removal of the object. Surgical intervention is recommended if the object has not passed spontaneously, has been present for >2 weeks, or if the patient becomes symptomatic with abdominal pain or rebound tenderness, guarding, nausea, or vomiting [29]. Such cases require a prompt referral to a gastroenterologist for diagnosis and management.
Bleeding
Major bleeding during dental implant placement is a rare complication, but can occur and may be life‐threatening. Failure to acknowledge the anatomical vascular variations in the maxilla and mandible can lead to iatrogenic vascular injury and major hemorrhage during implant placement. Many publications have reported that life‐threatening hemorrhage occurred most commonly when implants were placed in the anterior region of the mandible. Most patients experienced some degree of airway compromise necessitating intubation or the creation of a surgical airway (Figure 3.10). The bleeding is believed to be caused by lingual plate violation with the drill or implant with vascular injury to the terminal branches of the sublingual or submental artery (Figures 3.11 and 3.12) [30]. There may be tributaries of the terminal branches of the sublingual or submental arteries that enter the lingual aspect of the mandible through accessory lingual foramina in the lingual cortical bone (Figure