Discussion
Implant treatment can have several complications such as osseointegration failure (loosening), implant fracture, peri-implantitis, injury to surrounding structures such as nerves and vessels, and aspiration.1 One of the less common complications is migration into adjacent structures, most commonly into the maxillary sinus.1,2 Direct displacement of implant may occur for various reasons during implant insertion. This might be due to the dentist’s lack of skill and experience, inappropriate bone quality, excessive implant tapping, untreated perforation of the sinus lining (Schneiderian membrane), or application of too much force.4,6–9 Cases of implant migration into maxillary sinus are repeatedly reported, but implant displacement into other anatomical spaces like nasal cavity is scarce.2
We reported a case in which the implant was migrated into the maxillary sinus due to inappropriate insertion and blunder of the dentist. Then it accidentally moved into the nasal cavity because of the patient’s procrastination and attending to the specialist three months after his dentist’s order.
Up to the present, there are only four reports of implant migration into the nasal cavity in the literature which indicates how infrequent this complication is, considering the large number of implant treatments done in clinical practice (Table 1). Two of these studies have reported that the implant had migrated into the nasal cavity indirectly from the maxillary sinus through the ostium, as in our case.3,6While in the other two reports, implants had moved directly from the oral cavity to the nasal cavity by perforating the nasal floor.4,5
Although implant treatment itself is more prevalent in females, the current literature suggests that the prevalence of this complication is higher in males compared to females. However, this conclusion cannot be considered robust due to the low number of reported cases. It should be noted that the mean age of reported patients of implant migration is approximately one decade lower than the mean age of patients receiving implant treatment.10 Among the reported patients who have experienced migration of a dental implant to the nasal cavity, the youngest and oldest are respectively aged 23 and 65.
Extraction of the migrated implant by surgical operation was the treatment of choice in all studies, which had good prognosis in every one of these reports.5,6 However, in two studies it has been mentioned that the migrated implant is expelled spontaneously.3,4 In the study of Sanchis & Díaze, the implant accidentally was thrown off through the nose.4 But, in van de Loo et al.’s study, the implant disappeared after being detected in the CBCT.3 Most probably, the implant entered the gastrointestinal tract subconsciously and was thus excreted.
Implant migration into paranasal sinuses can cause pain, fungus-related infections, and sinusitis.6 In all reported cases of implant migration into the nasal cavity, patients have symptoms like nasal discomfort, nasal pain, and purulent discharge;3–6 on the contrary, the patient presented in this study did not experience any discomfort. The reason for being asymptomatic is uncertain. However, this could be explained by the short duration of the presence of the implant in the nasal cavity, the absence of sinusitis, and the aseptic surgical placement of the implant.
In this case, a possible reason for implant migration from the maxillary sinus into the nasal cavity can be the ciliary motion of the columnar epithelium of maxillary sinus membrane, which is toward the primary ostium, in combination with the patient’s head movements over time that made the implant move through ostium into the nasal cavity.
Since implant displacement after implant surgery is not uncommon,4 it is essential to use appropriate techniques, properly place the implants in a stable and assured situation, and schedule regular follow sessions. In case of implant migration, 3D imaging modalities such as CBCT are necessary to determine the exact place of implant insertion.5 Preoperative 3D imaging should be conducted prior to removing the migrated implant to precisely locate the implant. Due to the possibility of additional migration, the period between imaging and surgery should be kept minimum.
It is also vital to extract the migrated implant as soon as possible since it can move into other structures and cause further complications or cause acute and chronic sinusitis.11,12 Intraoral surgical and trans-nasal endoscopic procedures have both been documented for removing implants migrated to nasal and paranasal cavieties.13–15
Findings of this report could help dentists and surgeons prevent, diagnose, and manage accidental migration of dental implants into the nasal cavity.