Oral Biol Res 2017; 41(4): 207-214  https://doi.org/10.21851/obr.41.04.201712.207
Clinical progress of teeth and implant displaced into the maxillary sinus: retrospective clinical study
So-Hyun Kim1 , and Young-Kyun Kim1,2,*
1Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea,
2Professor, Department of Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 03080, Republic of Korea
Correspondence to: Young-Kyun Kim Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, 82 Gumi-ro 173beon-gil, Bundang-gu, Seongnam 13620, Republic of Korea Tel.: +82-31-787-7541, Fax: +82-31-787-4068 E-mail: kyk0505@snubh.org
Received: August 28, 2017; Accepted: September 11, 2017; Published online: December 31, 2017.
© Oral Biology Research. All rights reserved.


Because of the unique anatomical characteristics of the maxillary sinus, a tooth or implant may be accidentally displaced into the maxillary sinus for various reasons. The medical records, including symptoms, clinical examinations, a description of surgery and radiographs, were reviewed for 19 patients who were treated for the displacement of a tooth and implants into the maxillary sinus, between 2003 and 2015. Sixteen cases (84%) were implant displacement, while three other cases (16%) involved tooth displacement. Eleven cases (57.9%) were asymptomatic, while eight cases (42.1%) displayed symptoms. Psychological stress and nasal obstruction were the most common signs and symptoms, followed by nasal discharge, pain, and purulent discharge. Attempts at removal of the displaced material were made in 14 out of 19 (74%) cases; 5 patients (26%) were observed with using antibiotics. For removal, a majority of patients underwent surgery with the Caldwell-Luc approach while using general anesthesia. All of the symptoms disappeared after removing the displaced material. In these cases, clinicians should perform thorough assessments of the local anatomy using radiography prior to treatment. The appropriate healing period and type of treatment should be selected based the patient’s bone quality and bone mass, while avoiding an excessive use of instruments.

Keywords: Implant, Maxillary sinus, Tooth

Because dental procedures are performed in very near to the patient, a sudden movement by the patient or a careless movement by the dentist may cause displacement of the tooth, implant, or fragment of instrument into the soft tissues of the oral and maxillofacial area. In particular, residual tooth roots or implants placed in the maxilla are often displaced into the maxillary sinus or infratemporal fossa. This is primarily due to the use of inappropriate manipulation, sudden movement by the patient during treatment, or the lack of residual bone for implantation. Especially in the posterior maxillary area, low bone density, poor bone quality, rapid alveolar bone resorption, and pneumatization of the maxillary sinus often lead to loss of implant’s primary stability. In addition, marginal bone loss during healing may then hinder secondary implant stability and cause the implant to be displaced accidentally into the maxillary sinus [1, 2]. Implantation via the crestal approach in patients with the inadequate residual bone or poor bone quality may also result in displacement of the implant into the maxillary sinus. Displacement of material into the maxillary sinus not only results in medical complications but also may cause a patient to lose trust in the medical staff, potentially ending in a medical dispute. Therefore, it is important that dentists perform meticulous preoperative assessments and consider each patient’s unique anatomy prior to placing dental implants.

In spite of this, displacement of material into the maxillary sinus may still occur, and quick and accurate follow-up treatment would minimize secondary complications and restore a patient’s trust in the medical staff. However, little data exists that identifies the problems resulting from displacement of material into the maxillary sinus and the appropriate treatment for this. Accordingly, this study aims to identify the types of implants and teeth commonly displaced into the maxillary sinus, as well as the symptoms, complications, and treatments associated with displacement. We also present some representative case reports detailing displacement of the foreign body into the maxillary sinus.

Materials and Methods

The medical records including symptoms, clinical examinations, description of surgery and radiographs were reviewed for 19 patients who visited the Department of Oral and Maxillofacial Surgery at the Seoul National University Bundang Hospital between 2003 and 2015 to be treated for displacement of foreign body into the maxillary sinus. This retrospective clinical study was approved by the Seoul National University Bundang Hospital Institutional Review Board (B-1706-402-112). Thirteen patients were male (68%) and six were female (32%). The patients’ ages ranged from 21 to 67 years, with a mean age of 49.52 years. Sixteen cases (84%) involved implant displacement while three cases (16%) involved tooth displacement. There were 11 cases with the right (57.9%) and eight cases with the left (42.1%) sinus.

Regarding the time of displacement, each eight cases (42%) occurred during the implant surgery (primary and secondary) and after the implant surgery. In three cases (16%), it occurred during the tooth extraction procedure. Among the cases where it occurred during the implant surgery, in six cases it occurred during the primary surgery and in two cases were during the secondary surgery (Table 1).

Time of displacement

Time of displacement Patients  % 
During the implant surgery842
After the implant surgery (Postoperative) 842
During tooth extraction316



Eleven cases (57.9%) remained asymptomatic while eight cases (42.1%) had symptoms associated with the displaced material. In five cases, patients had multiple signs and symptoms (For example, Headache and nasal obstruction). Psychological stress and nasal obstruction were the most common symptoms, followed by nasal discharge, pain, and purulent discharge (Table 2). Patients with psychological stress had uncomfortable feelings associated with foreign material present within their bodies or developed fear associated with implant surgery; in one severe case, the patient developed a panic disorder.

Signs and symptoms

Signs and symptoms Patients (Including a duplication) 
Psychological stress4
Nasal obstruction4
Nasal discharge3
Pain (headache, sinus pain, on palpation) 3
Purulent discharge2

Treatments included removal of the displaced teeth or implant (53%), observation and use of antibiotics (26%), bone augmentation or re-implantation after removal of the displaced material (11%), and failed removal followed by irrigation and antibiotic therapy (11%) (Table 3). During the period of observation, pain medications, antibiotics, and radiographic imaging were prescribed. Removal of the displaced material was performed under general anesthesia in 12 out of the 14 cases in which it was attempted, while local anesthesia was used for the remaining two cases. The Caldwell-Luc approach was used in 13 cases and endoscopy was performed by an ENT in one case (Table 3).

Types of treatment

Treatment Patients  % 
Removal alone1053
Removal + bone augmentation or re-implantation 210.5
Removal + irrigation followed by observation210.5

Symptoms developed in one case with tooth displacement and eight cases with implant displacement. Complications associated with displacement included maxillary sinusitis (seven cases) and oral-maxillary sinus fistula (two cases, one with tooth displacement, and one with implant displacement). All symptoms disappeared after removing the displaced material. In one of the five cases in which the displaced material was not immediately removed and only observed, the implant was removed three years later by an ENT specialist, due to bilateral paranasal sinusitis. In two cases where had attempted the removal but failed, the symptoms eventually resolved in one case and the remaining case was lost to follow-up.

Case Reports

Case 1: Tooth displacement and removal

A 26-year-old female patient was undergoing extraction of the #28 tooth when it was displaced into the maxillary sinus. She developed purulent discharge and signs of maxillary sinusitis, which did not resolve with a two-week course of antibiotics, pain medications in a local dental clinic. The patient visited a local ENT clinic that referred her to our institution. The panoramic and occipitomental (Water’s) radiograph showed displacement of the #28 tooth into the maxillary sinus, thickening of the left maxillary sinus mucosa, and an oral-maxillary sinus fistula (Fig. 1).

Fig. 1.

Case 1: Displacement of the #28 tooth: Panoramic and occipitomental (Water’s) views taken at the first examination

Under general anesthesia, a 1.5-cm sinus window was created in the anterior wall of the maxillary sinus via the Caldwell-Luc approach. An endoscope was then inserted to explore the location of the displaced tooth and associated inflammation of the maxillary sinus. After removing the displaced tooth and surrounding inflamed tissue, the maxillary sinus was irrigated with normal saline and suture was done with 4-0 vicryl. After the surgery, the incision was dressed and antibiotics were prescribed. We ceased observation of the patient when the clinical symptoms resolved completely approximately two months postoperatively (Fig. 2).

Fig. 2.

Case 1: Panoramic and occipitomental (Water’s) views obtained two months after removal of the displaced tooth

Case 2: Implant displacement and removal

A 54-year-old male patient presented to our institution for discomfort in the right facial area. Implants had been placed at #15, 16, and 17, approximately three months prior to presentation and re-implantation had been performed at #15 a month ago. Pain medication had been prescribed a week prior to presentation, which was effective in controlling the pain in the right side of his face and implant sites. The patient visited our institution when the right nasal obstruction and foul-smelling nasal discharge persisted. Other than controlled hypertension, the patient did not have any notable medical history. On examination, the patient had tenderness in the right posterior maxillary region. A panorama view revealed displacement of the #17 implant into the maxillary sinus while Water’s view showed increased radiopacity of the right maxillary sinus (Fig. 3). Computed tomography confirmed increased radiopacity of the entire right maxillary sinus and revealed the 3-dimensional position of the displaced implant (Fig. 4). The height of the residual bone in the posterior region was approximately 3 mm due to pneumatization of the maxillary sinus.

Fig. 3.

Case 2: Displacement of the #17 implant into the maxillary sinus: Panoramic and occipitomental (Water’s) views taken at the first examination

Fig. 4.

Case 2: Displacement of the #17 implant: First CT.

The patient visited the hospital approximately one month later for the removal of the #17 implant. He reported that another panorama view had been obtained a few days previously that revealed displacement of a second implant. The new images were reviewed, which confirmed that the #16 implant was also displaced into the maxillary sinus and that the #17 implant had migrated within the maxillary sinus (Fig. 5).

Fig. 5.

Case 2: Displacement of the #16 implant into the maxillary sinus; change in position of the #17 implant

A flap over the #14-18 teeth was elevated and a lateral window into the maxillary sinus was created under general anesthesia. Purulent material present in the maxillary sinus was removed with saline irrigation. After removal of the two displaced implants, the maxillary sinus mucosa was elevated and the perforated mucosa was repaired with a resorbable collagen membrane (BioArm: ACE Surgical Supply Company Inc., Brockton, MA, USA and Tisseel: Baxter AG, Wien, Austria). Bone augmentation of the maxillary sinus was performed (ExFuse: Hanmi Medicare Inc., Seoul, South Korea), after which time the window was sutured closed. Four months after the surgery, panorama and CT images confirmed that the radiopacity of the right maxillary sinus had nearly resolved completely. The patient was also noted to be asymptomatic (Fig. 6).

Fig. 6.

Case 2: Panorama and CT after removing #16 and #17 implants

Case 3: Observation without removal of the displaced implant

A 55-year-old female patient presented for evaluation after having undergone bone augmentation and implantation at the #16 and #17 teeth at a local clinic one year previously. The #17 implant had been removed, and the #16 implant was displaced into the maxillary sinus, when the patient was referred to our institution. She had symptoms of temporomandibular disorders but none of maxillary sinusitis. Observation over the past year and a current panorama view (Fig. 7) showed no evidence of right maxillary sinusitis, so regular monitoring was recommended.

Fig. 7.

Case 3: Displacement of the #16 implant

There were no notable changes in the patient’s clinical signs or in the appearance of the implant at the one- and six-month follow-up (Fig. 8) visits, and the patient did not return to the hospital for approximately 2.5 years. The patient then re-presented with tickling around the right side of the nose and frequent sneezing. A panorama view showed that the implant was further displaced into the maxillary sinus (Fig. 9). Computed tomography revealed maxillary sinusitis on the side contralateral to the displaced implant and bilateral paranasal sinusitis (Fig. 9). The patient was then referred to the ENT department and the displaced implant was removed via endoscopy. All of the patient’s symptoms then resolved.

Fig. 8.

Case 3: Panorama view obtained six months after the first examination

Fig. 9.

Case 3: Panorama and CT images obtained 2.5 years after the first examination


Maxillary posterior teeth or implants may be displaced into the maxillary sinus during extraction or implantation due to the anatomical structure of this area. One study reported that 0.6-3.8% of the material introduced into the paranasal sinus is iatrogenic [3]. Therefore clinicians must take precautions when extracting posterior teeth because inappropriate handling of instruments without full visualization of the area or use of excessive force may displace the tooth or residual roots into the maxillary sinus [3, 4]. Further, the risk of displacement increases when the implantation is performed with the maxillary sinus mucosa lifted via the crestal approach in patients with inadequate bone mass or poor bone quality secondary to pneumatization. Several studies have reported that a lateral approach is preferred for the maxillary sinus lift when the height of the residual bone is less than 4-5 mm [5, 6].

In this study, approximately 84% of the cases of displacement into the maxillary sinus involved an implant while 16% involved a tooth. Displacement occurred more frequently in male patients (68%) than it did in female patients (32%). Displacement was as likely to occur during implant surgery as it was to occur after. In other words, there is a risk that implants may be displaced into the maxillary sinus not only during but also after surgery owing to marginal bone resorption, which calls for careful observation on the part of the surgeon. All cases of tooth displacement occurred during the extraction procedure, suggesting that clinicians should take precautions when maneuvering instruments during the extraction of maxillary posterior teeth.

Discomfort, paresthesia when in close proximity to a nerve, pain, swelling, maxillary sinusitis, cellulitis, and abscess formation have been suggested as potential complications of displacement of a foreign body into the maxillary sinus [4, 7, 8]. In our study, more than half of the patients (57.9%) were asymptomatic, with the remaining 42.1% complaining of symptoms associated with maxillary sinusitis and psychological stress. The main symptoms noted were nasal obstruction, nasal discharge, and pain. Seven patients (37%) were definitively diagnosed with maxillary sinusitis, and in severe cases, patients developed an oral-maxillary sinus fistula. Although the majority of patients were asymptomatic, the fact that the patients with psychological stress suffered from insomnia due to a foreign body sensation, fear of dental treatment, and even a severe panic disorder allows us to speculate that these patients suffered from severe pain. Furthermore, in one case, the displacement negatively affected the patient’s trust in the medical staff, which eventually led to a medical dispute. It is important to note that even if a patient does not show any symptoms in the short-term, an implant or tooth may eventually cause maxillary sinusitis by impairing the mobility of the maxillary sinus cilia, inducing a foreign body reaction, or obstructing the nasal meatus by moving within the maxillary sinus [9-11].

Treatment consisted of removal of the displaced material or observation. Removal was attempted in most cases, but observation while treating with antibiotics, anti-inflammatory medications, and steroids was chosen for patients without clinical symptoms. The symptoms mostly resolved in both patients who were observed from the beginning and in those patients who were later placed on observation after the displaced material could not be removed. The clinical symptoms resolved in all cases that were followed, but two were lost to follow-up. Whether the displaced material must be removed or not is still controversial. Some arguing that all displaced materials must be removed even in asymptomatic patients in order to prevent psychological stress and other secondary complications [12, 13]. Due to the anatomy of the maxillary sinus, which has ciliated mucosa and an empty cavity, displaced material can continue to move within it, necessitating regular imaging to closely monitor the location of the material. Furthermore, once symptoms of maxillary sinusitis, infection, and neuropathy develop, the displaced material must be removed promptly, at which time the patient should be referred to an oral-maxillofacial specialist or an ENT.

If material is displaced into the maxillary sinus during surgery, the surgeon should immediately try to remove the displaced material while ensuring a full field of view via hemostasis and saline irrigation. The material may be removed via powerful suction or water pressure, or it can be removed manually by carefully detaching the maxillary sinus mucosa. However, probing without a full field of view is not recommended, as this may cause the substance to be further displaced into the tissue [8]. Surgeons must also note that the displaced material may be located in a position different from that shown in the radiographs due to the fluidity of the maxillary sinus mucosa. In cases where the material cannot be removed, the surgeon should irrigate the wound adequately, apply sterile gauze, and use antibiotics, pain medications, and serial radiographs while observing clinical symptoms to evaluate progress. Furthermore, the patient should be instructed to avoid severe coughing or sneezing episodes as much as possible [8]. In our study, attempts at removal of the displaced material were made in 14 out of 19 (74%) cases, 12 of which were performed under general anesthesia (85.7%) while two were performed under local anesthesia. Most surgeries (n=13) were performed using the Caldwell-Luc approach. Endoscopic assistance could be used aid the surgeon in accurately locating and removing the material. Minimally invasive, endoscopic removal has been on the rise in recent years and has been reported to be safe, causing little soft tissue damage and resulting in good outcomes [4, 10-12]. Remaining normal maxillary sinus mucosa must not be removed because it has the potential to heal completely after removal of the displaced material. Although all of the cases reviewed in this study had good outcomes after removal of the displaced material and numerous other studies have noted that removing the material eliminated severe complications, preventing the displacement of material into the maxillary sinus in the first place would be the best scenario. This is considering the fact that removal of the material under general anesthesia may inflict psychological stress and that displacement of the teeth or implants in the first place could be detrimental to the doctor-patient relationship. To this end, clinicians should perform thorough assessments of the local anatomy using radiography and CT prior to treatment. A careful choice between the crestal and lateral approach should be made depending on the height of the residual bone. The appropriate healing period and type of treatment should be chosen based the patient’s bone quality and bone mass while avoiding the excessive use of instruments.

Conflict of Interest

The authors declare that they have no competing interests.


So-Hyun Kim 0000-0002-6476-4857

Young-Kyun Kim 0000-0002-7268-3870

  1. González-García A, González-García J, Diniz-Freitas M, García-García A, and Bullón P. Accidental displacement and migration of endosseous implants into adjacent craniofacial structures: a review and update. Med Oral Patol Oral Cir Bucal 2012;17:769-774. doi:10.4317/medoral.18032
  2. Iida S, Tanaka N, Kogo M, and Matsuya T. Migration of a dental implant into the maxillary sinus. A case report. Int J Oral Maxillofac Surg 2000;29:358-359. doi:10.1016/S0901-5027(00)80052-1
  3. Bouquet A, Coudert JL, Bourgeois D, Mazoyer JF, and Bossard D. Contributions of reformatted computed tomography and panoramic radiography in the localization of third molars relative to the maxillary sinus. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:342-347. doi:10.1016/j.tripleo.2004.02.082
  4. Gao QM, Yang C, Zheng LY, and Hu YK. Removal of Long- Term Broken Roots Displaced Into the Maxillary Sinus by Endoscopic Assistant. J Craniofac Surg 2016;27:77-80. doi:10.1097/SCS.0000000000002235
  5. Fugazzotto PA. Augmentation of the Posterior Maxilla: A Proposed Hierarchy of Treatment Selection. J Periodontol 2003;75:1682-1691. doi:10.1902/jop.2003.74.11.1682
  6. Pjetursson BE, Rast C, Brägger U, Schmidlin K, Zwahlen M, and Lang NP. Maxillary sinus floor elevation using the osteotome technique with or without grafting material. Part I : Implant survival and patient's perception. Clin Oral Implants Res 2009;20:667-676. doi:10.1111/j.1600-0501.2009.01704.x
  7. Woolley EJ, and Patel M. Subdural empyema resulting from displacement of a root into the maxillary antrum. Br Dent J 1997;182:430-432.
  8. Kim YK, Lee YJ, Yoon PY, Choi YH, and Kim SG. Complication Q&A in dentistry. Seoul: DaehanNarae Publishing; 2015 p. 29-30.
  9. Eltas A, Dundar S, Eltas SD, Altun O, Yolcu U, and Saybak A. Accidental Displacement of Dental Implants Into Both Maxillary Sinuses During Surgery. J Oral Implantol 2015;41:601-603. doi:10.1563/AAID-JOI-D-13-00026
  10. de Jong MA, Rushinek H, and Eliashar R. Removal of dental implants displaced into the maxillary sinus: A case series. Eur J Oral Implantol 2016;9:427-433.
  11. Kitamura A. Removal of a migrated dental implant from a maxillary sinus by transnasal endoscopy. Br J Oral Maxillofac Surg 2007;45:410-411. doi:10.1016/j.bjoms.2005.12.007
  12. Matti E, Emanuelli E, Pusateri A, Muniz CC, and Pagella F. Transnasal Endoscopic Removal of Dental Implants from the Maxillary Sinus. Int J Oral Maxillofac Implants 2013;28:905-910. doi:10.11607/jomi.2894
  13. Chiapasco M, Felisati G, Maccari A, Borloni R, Gatti F, and Di Leo F. The management of complications following displacement of oral implants in the paranasal sinuses: a multicenter clinical report and proposed treatment protocols. Int J Oral Maxillofac Surg 2009;38:1273-1278. doi:10.1016/j.ijom.2009.09.001

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