Also, there may be an arterial anastomosis between the sublingual and submental arteries that occurs 10% of the time. In a systematic review [30], all patients who suffered massive bleeding had received implants ≥15 mm in length. Another contributing factor to an increased frequency of bleeding is a significantly elevated systolic blood pressure at the time of vascular injury and hematoma formation leading to expansion of the hematoma. Treatment includes airway management and control of the hemorrhage, and an evaluation in an emergency department with probable, hospital admission. Basic measures to control bleeding such as immediate application of pressure on the site of suspected vascular injury, as well as blood pressure control, should be performed. Administering a local anesthetic solution with a vasoconstrictor can be useful as well. It has been suggested that arterial ligation may be technically difficult due to the engorgement of the tissues and the retraction of the offending vessel into the deeper tissues of the floor of the mouth, and should only be performed in cases of uncontrollable bleeding with no other available acute treatment options. If surgical intervention is deemed necessary, an extraoral approach for arterial ligation is preferred, but angiography with embolization remains the mainstay of therapy in a hospital imaging center (Algorithm 3.4). Medical management should involve the use of systemic antibiotics to prevent infection of the hematoma, and corticosteroids can help to reduce swelling and limit further airway compromise.
Fig. 3.10. Floor of mouth hematoma following anterior mandible implant placement.
Fig. 3.11. Implant violation of the lingual plate that may transect the sublingual or submental vessels leading to floor of mouth hemorrhage.
Fig. 3.12. CBCT view showing the violation of the lingual cortex by an implant.
Fig. 3.13. Lingual nutrient canal in the anterior mandible that may lead to floor of mouth bleeding from implant placement.
Algorithm 3.4: Bleeding
Brisk and pulsatile arterial bleeding can also occur during a maxillary sinus grafting procedure prior to an implant placement. The maxillary sinus receives blood supply from the posterior superior alveolar, infraorbital, and posterior lateral nasal arteries, and they are at risk of being injured with rotary instruments. The intraosseous course of the posterior superior alveolar artery, known as the alveolar antral artery, may be visible during exposure of the lateral maxillary wall for sinus grafting and attempts should be made to either avoid it, if possible, or cauterize it, prior to creation of the lateral bony window. The alveolar antral artery, or the intraosseous posterior superior alveolar artery (PSA) or anastomosis of the terminal branches of the infraorbital artery and PSA, is usually located 19 mm above the maxillary alveolar crest. Due to the caliber of the blood vessels and its retraction into the osseous canal, tamponade with gauze pressure may not be entirely effective. Bone wax may not adhere due to constant bleeding, and burnishing of the bone may not be possible. Therefore, use of hemostatic agents such as a topical thrombin sponge (or gelatin sponge [gelfoam]) or microfibrillar collagen (Avitene) should be considered [31] (Algorithm 3.4).
Air Embolism
The rare, fatal complication of air embolism has been associated with dental implant placement. In all cases described in the literature, air was introduced into the cancellous marrow spaces in the mandible forming an air embolism propagated into the venous system. The air embolus then travels to the superior vena cava and subsequently into the right atrium resulting in cardiopulmonary collapse, leading to cardiac arrest. In all reported cases, implant drills with a combination of air and water internal irrigation were used. This complication can be prevented by using implant drills that are not air‐driven, and do not have irrigation systems that are driven by air pressure. This complication is not limited to implant surgery, as several incidents have been reported in patients undergoing other dental‐related procedures. Again, in these cases, air–water‐driven irrigated drills have been implicated as the source of the introduction of air into the venous system.
Mandible Fracture
The occurrence of a mandible fracture is an uncommon complication due to dental implant reconstruction, and has been reported almost exclusively in the atrophic, completely edentulous mandible. Several factors need to be considered when treatment planning for these cases. The first consideration is that not every mandible is a candidate for implant reconstruction, and the benefits must outweigh the risks especially in the case of a severely atrophic mandible. Imaging needs to delineate clearly not only the height of the mandible, but also the width. A minimum height of 7–10 mm and a minimum width of 6–8 mm of bone are required for implant placement. In most reports, mandible fractures occurred after the restoration of the implants, and the prosthesis was in function for a period of months to years. Mandible fractures secondary to implant reconstruction immediately, or prior to prosthetic reconstruction, are rare, and again, typically occur in atrophic edentulous mandibles (Figure 3.14). The treatment should follow basic trauma principles regarding atrophic mandible fractures (Algorithm 3.5). Immobilization and fixation with a locking reconstruction plate is necessary for stability, and bone grafting may be necessary given the cortical, noncancellous, nature of the atrophic mandible rendering the healing capacity of the atrophic mandible less than optimal (Figure 3.15). Additional bone grafting for augmentation may also be considered before implant placement in the atrophic, edentulous mandible. Several techniques have been described to facilitate reconstruction of the atrophic mandible. Although the use of the transmandibular implant had been advocated as a solution for the severely atrophic mandible, more recent evidence suggests that long‐term outcomes may not be superior (or comparable) to traditional techniques of implant placement, and this form of mandibular reconstruction has fallen out of favor over the years.
Fig. 3.14. Right mandible fracture from implant placement.
Algorithm 3.5: Mandible Fracture