Foreign body aspirations in dental clinics: a narrative review.

Foreign body aspiration can produce a medical emergency. Obstruction of the airways can be life-threatening, and complications may develop in less-severe cases if it is left untreated. Although it is more prevalent in children by approximately three times, adults can still experience it, and it is more frequently related to healthcare in adults. Objects used in dental treatment are usually placed in the oral cavity and can be ingested or inhaled by accident. Dental treatment has been identified as an important cause of the misplacement of foreign bodies in the airway. However, few reports have been published on dentistry-related foreign body aspiration. This paper discusses the disease course, management, and clinical outcomes of foreign body aspiration, especially those associated with dentistry. The patient must be examined for respiratory distress. If the patient is unstable, urgent airway management and the maneuvers for removal should be performed. Radiographs and computed tomography can help identify and locate the object. The treatment of choice is often bronchoscopy, and both flexible and rigid endoscopes can be used depending on the situation. Preventive measures need to be implemented to avoid inhalation accidents given the potential consequences. Though the incidence is rare, healthcare levels need to be enhanced to avert morbidity and mortality. Radiological evaluation and bronchoscopy are vital for management.

INTRODUCTION

Foreign body aspiration may require urgent medical attention. If an object obstructs the airway completely and management is delayed, the patient could die or suffer hypoxic brain injuries [12]. Recognizing an event and providing appropriate care can be lifesaving. Unnoticed aspiration accidents can lead to various pulmonary complications [34].

Objects related to dental practice are vulnerable to aspiration because of their position in the oral cavity. In dental clinics, events can occur regardless of the time or type of procedure. These critical events require prompt referral in dentistry [56]. As in other foreign body aspiration cases, dentistry-related aspirations also require timely intervention because the medical consequences can include a critical state or death in severe cases [78]. Prevention and management measures must be in place; otherwise, practitioners may be held liable for various claims [910].

Few reports on foreign body aspiration in dental clinics and associated medical departments have appeared in the literature, despite the importance of understanding it, and no consensus regarding its management has emerged. Complications and prognoses are not well-known. Thus, this narrative review discusses the disease course, treatment modalities, and outcomes of dental object inhalation.

INCIDENCE

Most of the foreign bodies that enter beyond the oral cavity tract are ingested into the gastrointestinal tract, and only a small percentage is aspirated into the airway [51112], due to the anatomy of the pharynx and physiology of the swallowing process [13]. This is also true of cases involving dental materials. A retrospective study of accidental ingestion or aspiration over five years at a university-run dental clinic in Japan found no cases of aspiration among 23 patients [11]. A systematic review of retained foreign objects during dental procedures found that 89.5% of cases were ingestion cases and only the remaining 10.5% were aspiration cases [5]. Despite their lower incidence, aspirated cases are potentially more dangerous, as they are more frequently life-threatening [14].

Foreign body aspiration is a common cause of emergency room visits in children. In the United States, the incidence was 29.9 per 100,000 people in 2001, and the estimated number of emergency room visits was 17,537 [15]. For adults, the incidence is lower, and cases occur in about one third of children [1617], with most patients aged three years or less [1618]. The predisposition of younger patients to foreign body aspiration can be explained by their tendency to place objects in their mouth, lack of teeth, and immature swallowing coordination [18]. Children have small airways, and the locations of foreign bodies in their airways differ from those in adults. A report of a single-center experience of over 20 years found that foreign bodies were located in the proximal airways (larynx, trachea, right and left main bronchus) more frequently in children (74%) than in adults (43%) [16]. This discrepancy may be attributable to the size of the airways. Among adults, foreign body aspiration most typically occurs in patients aged 60 or more [519]. Adult cases are more commonly associated with healthcare equipment [20], with dental materials identified as one of the most common causes. [2021]. The occurrence (cases/dentists) per year has been reported to be 0.021 by French insurance companies [22]. Over a four-year period at a dental hospital in Tokyo, 0.0038% of the annual cumulative number of patients at the hospital experienced ingestion or aspiration, and among the 40 patients, aspiration was found in one patient [23]. Another report from a dental clinic in North Carolina found 36 cases of ingestion or aspiration over a 10-year-period and one patient with a dental foreign body in the airway [24] (Table 1).

Table 1

Incidence of ingestion or aspiration in dental clinics

Report (Author, year of publication)	Number of ingestion cases	Number of aspiration cases	Duration of the study period	Number of patients treated in the clinic
Susini et al., 2007 [22]	464	44	11 years	24651
Hisanaga et al., 2010 [12]	11	0	1 year	933.1 per day
*Obinata et al., 2011 [11]	23	0	5 years	NA
Tiwana et al., 2004 [24]	25	1	10 years	100000 per year on average
†Hisanaga et al., 2014 [23]	39	1	4 years	NA

*, incidence of ingestion was 0.0037% per year; †, incidence of ingestion or aspiration was 0.0044% per year; NA, not available.

A review conducted by Hou et al. found that aspiration was common in implantation, prosthodontics, and restorative dentistry [5]. The most commonly aspirated dental items were prostheses, inlay cores, dental crowns [111222], and screw drivers [3] (Table 2). In pediatric cases, extracted teeth are commonly swallowed [1125]. The years of professional experience of the practitioners involved in the cases have tended to be shorter [111225]. Reports show that no specific times of day are associated with more frequent accidents [111225].

Table 2

Aspirated dental items reported in review articles [222324]

Aspirated objects	Number of cases
Prosthesis & Crown	32
Inlay	7
Screw post	5
Amalgam	2
Endodontic file	1

Data presented as number (%).

Dentures can also be ingested or aspirated. A literature review conducted between 2009 and 2019 identified 85 cases worldwide. More men (84.7%) were involved, and most patients did not have cognitive dysfunction (77.4%). Eating (15.2%), sleeping (8.2%), and intubation (7.1%) were common precipitating events [26].

The risk factors for the aspiration of foreign bodies in dentistry have not been fully elucidated. The anecdotal nature of most reports in the literature limits analysis. Neurologic disorders, dental procedures, medical procedures, loss of consciousness due to trauma, and alcohol or sedative use have been found to be predisposing factors for foreign body aspiration among adults in retrospective studies [2027]. Potential risk factors for foreign body aspiration during dental procedures include intravenous sedation, local anesthesia, supine position, inadequate lightning, ineffective assistants [528], professional experience of the practitioner [111225], and specific types of procedures [512]. Further studies are required to validate these results.

CLINICAL MANIFESTATION

Foreign body aspiration can cause various symptoms and signs. The type of aspirated material and the location of the aspirate in the bronchial tree, the length of time between aspiration and diagnosis, and the host’s response to foreign bodies may be related to variable clinical manifestations [293031]. Clinical manifestations may range from asymptomatic to fatal.

In children, the typical response after foreign body aspiration is choking [32]. Choking may have a high predictive value for the presence of a foreign body in the airway [33]. Other common symptoms include cough, vomiting, and dyspnea [34]. The most common finding on physical examinations is decreased breath sound on the affected site [3335]. Other possible findings include stridor, which is indicative of an upper airway obstruction. Wheezing, cough, and decreased breath sounds have been described as the classic triad. The specificity has been reported to be high [33343536], but recent studies show that only around 15% [3334] present with the classic triad. Dyspnea accompanied by wheezing can lead to misdiagnosis as asthma [3738] or acute bronchiolitis [39] (Table 3).

Table 3

Symptoms and signs of all-cause aspirations in the reviewed articles

Report (Author, year)	Patient characteristics	Number of cases	Symptoms	Signs
Nasir, et al., 2021 [33]	Patient < 11	16	Cough (69%), dyspnea (69%), vomiting (56%)	Stridor (31%), fever (31%), cyanosis (25%)
Oguz, et al. 2000 [35]	Pediatric	53	Cough (54.5%), vomiting (7.5%), dyspnea (5.6%)	Unilaterally decreased breathing sound (52.8%), wheezing (45.2%), Cyanosis (41.5%)
Midulla, et al., 2005 [34]	Pediatric	82	Cough (75.7%), dyspnea (38.6%), gasping (5.7%)	Localized decreased breath sound (62.8%), Localized wheezing (30%), diffuse wheezing (25.7%)
Paksu, et al., 2012 [36]	Pediatric	147	Cough (81.0%), dyspnea (60.0%), vomiting (13.9%)	Localized decreased breath sound), wheezing (27.0%), tachypnea (16.8%)
Ramos, et al., 2009 [21]	Patients > 14 years old	32		NA
Soysal, et al., 2006 [114]	Patients who underwent bronchoscopy after diagnosed with foreign body aspiration	140	Cough (60.7%), dyspnea (39.3%)	Decreased breathing sound (50%), rales (50%), tachypnea (50%)
Foltran, et al., 2012 [2]	Meta-analysis, patients of all ages	174 articles, 30,477 patients	Cough (61.2%), choking (46.8%), dyspnea (34.6%)	Decreased respiratory movement (65.9%), decreased air entry (63.3%), decreased sound (50.4%)

NA, not available.

Adults are often asymptomatic or have milder symptoms [4041]. The most common symptom after foreign body aspiration is cough, followed by dyspnea [4243]. Other notable symptoms included hemoptysis [4142], choking [1621], fever [1644], and vomiting [41] (Table 3).

Foreign body aspiration can also cause negative-pressure pulmonary edema. Negative thoracic pressure is induced by inspiratory effort in the presence of an obstructed glottis. Negative pressure results in high permeability or hydrostatic edema. To manage this, the airway must be secured via endotracheal intubation. Positive-pressure ventilation with supplementary oxygen is then provided. Although pulmonary edema usually resolves within 24–48 hours, further management may be needed in patients with severe hypoxemia. Diuretics, low tidal volume ventilation, and β-agonists are options [45].

Various airway tissue reactions, including inflammation, granulation, endobronchial stenosis, and edema, can result from foreign body aspiration [46]. Stenosis can result in dyspnea, sputum production, chest pain, and fever with obstructive infection. Tissue response is related to the nature of the aspirate and duration since aspiration. Organic foreign bodies remaining in the airway for longer periods cause more mucosal irritation, leading to chronic inflammation and granulation [47]. Inorganic materials incite less inflammation but cause direct trauma and can be wedged in the bronchial tree [48]. Aspirations associated with dental procedures are typically composed of inorganic materials. A review of dental aspirations found that the most common aspirated objects were prostheses/crowns (58.2%), followed by inlay cores (12.7%), and screwdrivers/screws (10.9%). Other reported objects include endodontic files/reamers, bridges, and burs/drills [5].

EVALUATIONS

Early management of foreign body aspiration requires an evaluation of the patient’s respiratory state. Signs of patient instability must be checked [49]. Patients with respiratory distress require maneuvers for removal and emergency airway management [50]. Stable patients are likely to have only partial obstruction, but caution needs to be taken to avoid complete obstruction or a displacement of the foreign body deeper into the airway via diagnostic or therapeutic maneuvers [49] (Fig. 1).

Fig. 1

Summary of management flow when dental material aspiration is suspected. CT, computed tomography.

In stable patients, the location and identity of the foreign body must be evaluated [49]. Imaging studies are essential at this stage. They confirm that foreign bodies are indeed present and can help identify the object. Moreover, the location of the object and associated complications needs to be examined [515253]. Radiographs play an important role [5152535455]. Radiographs are inexpensive, widely available, and sensitive for detecting radiopaque objects [53]. Secondary findings of airway obstruction such as air trapping, atelectasis, mediastinal shifting, and consolidation can also be detected [53]. However, some foreign bodies are undetectable, and radiographs are not sensitive to other tracheal and bronchial disorders [53].

Multidetector computed tomography (MDCT) can be used in cases where radiographs are inconclusive [5154]. MDCT provides not only rapid examination but also reconstructed two-dimensional (coronal and sagittal) and three-dimensional (virtual bronchoscopy) images. [5356]. The virtual bronchoscopy can provide views of the internal walls of the tracheobronchial tree, thus accurately depicting the location of the foreign body and related changes [156]. MDCT can also aid in correcting previous misdiagnoses of aspirations as another condition, such as acute bronchiolitis [39]. A systematic review of the central airways via CT can improve the detection of abnormalities that may go unnoticed [57]. Owing to its high sensitivity (100%) and specificity (98%), MDCT has been advocated as a diagnostic tool to avoid routine bronchoscopy in suspected cases of foreign body aspiration [58]. However, MDCT has several disadvantages. Exposure to radiation is potentially harmful, and the use of contrast media has adverse effects in some populations [53]. Access to this modality might also be limited. Unlike bronchoscopy, MDCT cannot be used for diagnostic and therapeutic purposes.

While bronchoscopy is the treatment modality of choice for the retrieval of foreign bodies in the airway, flexible bronchoscopy can also be used for diagnostic purposes. Patients who are suspected of aspiration without abnormal physical examination and radiologic findings should receive bronchoscopy [2759] (Fig. 2). The procedure is relatively easy, safe, and cost-effective [4160]. As relatively few adult patients remember the aspiration event, bronchoscopy can be considered if the patient has recurrent lung disease or risk factors for aspiration but the results of imaging studies are ambiguous [27].

Fig. 2

Case of 74-year-old woman who presented with dyspnea. (A) Chest computed tomography showing a calcified foreign body in the left main bronchus. (B) Bronchoscopic visualization of the foreign body. (C) Flexible bronchoscopy with a retrieval basket was performed to remove the foreign body. Granulated tissue was observed after the removal.

TREATMENT

1. Initial bystander-assisted removal of foreign body object

Coughing should be encouraged in conscious patients. If the foreign body is not removed via cough and the object is seen in the mouth, manual removal can be considered. Blind finger sweeps should be avoided because they can dislodge the object or inflict injury to the nasopharynx [61]. When such attempts fail, further management depends on the degree of respiratory distress. Tachypnea, nasal flaring, retractions, and cyanosis are warning signs [62]. When warning signs are absent, the patient can be referred to the medical department for radiological evaluations, elective removal procedures, or observation. However, in cases of severe obstruction, healthcare providers with expertise in airway management should be consulted immediately [63]. Additional potential bystander interventions include abdominal thrusts and back blows. Abdominal thrusts and the Heimlich maneuver have yielded better survival rates, with satisfactory neurological outcomes. However, major complications, including traumatic damage to the abdominal organs and vessels, have been reported [6465]. An abdominal thrust maneuver is contraindicated in infants, and back blows are now recommended prior to abdominal thrusts [61]. To perform back blows, the care provider must stand behind the patient, place one arm across the chest, lean the patient forward, and then slap five times between the shoulders with hand heels. Abdominal thrusts can be performed when back blows are ineffective. The maneuver is performed by the care provider by standing behind the patient, wrapping the arms around the upper abdomen, two inches above the belly button, then making a fist with one hand with the other hand held tightly over the fist and thrusting five times inward and upward [66]. The maneuvers can be repeated. If the patient becomes unconscious during the process, cardiopulmonary resuscitation should begin.

2. Rigid and flexible bronchoscopy

Both rigid and flexible bronchoscopies can be performed by an endoscopist for foreign bodies retained in the airways. It has been reported that 0.16 to 0.33% [2127676869] of all adult bronchoscopy cases are due to foreign bodies in the airway. Flexible endoscopy constitutes most bronchoscopy cases globally, especially in adults [7071] (Table 4).

Table 4

Treatment and mortality for all-cause aspiration in reviewed articles

Report (Author, year)	Patient characteristics	Number of patients	Flexible BS, success rates	Rigid BS, success rates	Surgery requirement	Mortality
Ramos, et al., 2009 [21]	Patients > 14 years old	32	NA	NA	15.6%	0%
Mise, et al., 2008 [27]	Adult patients who underwent flexible BS for foreign body removal	86	98.8%	NA	1.2%	0%
Debeljak, et al., 1999 [67]	Adult patients who underwent BS for foreign body removal	62	67.7%	96.8% (after both flexible and rigid bronchoscopy	1.6%	0%
Casalini, et al., 2013 [68]	Patients who underwent BS for foreign body removal	159	96%	100%	0%	0%
Boyd, et al., 2009 [69]	Adult patients who underwent BS for foreign body removal	20	90%	NA	0%	20%
Pasaoglu, et al., 1991 [115]	Pediatric patients who underwent BS for foreign body removal	639	NA	96.7%	0.3%	7.8%
De Palma, et al., 2020 [116]	Patients < 16 years who underwent BS for foreign body removal	51	97%	67%	0%	0%
Boufersaoui, et al., 2013 [72]	Patients < 18 years who underwent BS for foreign body removal	2624	NA	97%	2.6%	0.26%
Ganie, et al., 2014 [73]	Patients who underwent BS for foreign body removal	55	NA	94.5%	5.5%	0%
Dorterler, et al., 2019 [74]	Patients < 16 years who underwent BS for foreign body removal	86	NA	100%	0%	0%
Goyal, et al., 2020 [75]	Pediatric patients treated for foreign body aspiration	37	NA	94.6%	5.4%	0%
Dong, et al., 2012 [40]	Adult patients admitted for foreign body aspiration	200	96.5%	NA	3.5%	0%
Cutrone, et al., 2011 [76]	Children admitted for foreign body aspiration	206	NA	99.5%	0.5%	0%
Fang, et al., 2015 [77]	Adult patients who underwent BS for foreign body removal	94	90.4%	100%	1.1%	0%
Tang, et al., 2009 [80]	Pediatric patients who underwent flexible BS for foreign body aspiration	1027	91.3%	100%	0%	0%
Swanson, et al., 2002 [78]	Patients ≤ 16 years who underwent BS for foreign body removal	39	100%	86.7%	0%	0%
Kim, et al., 2018 [79]	Pediatric patients who underwent flexible BS for foreign body aspiration	20	90.0%	NA	10%	0%
Hou, et al., 2017 [5]	Review of case reports of dental foreign body aspiration	20	NA	NA	5%	0%

BS, bronchoscopy; NA, not available.

Rigid bronchoscopy is the method of choice for foreign body removal in children [31]. The advantages of rigid bronchoscopy include better resolution and a larger diameter. The procedure’s success rate in children is very high, with only a few cases requiring surgical intervention. In a case series of 2,624 patients from Algeria, the success rate was 97% [72]. Other international studies have reported comparable rates [737475]. However, rigid bronchoscopy is not available in most healthcare facilities and requires general anesthesia [63].

Flexible bronchoscopes are widely used in adult patients with foreign body airway obstruction [63]. They can be used for both diagnosis and treatment. They cause less trauma and can reach the more distal bronchi [76]. The procedure can be performed under moderate sedation instead of general anesthesia and muscle relaxants [77]. Even among pediatric patients, reports of foreign body removal under flexible bronchoscopy are growing, with success rates comparable to those of procedures with rigid bronchoscopes [7879]. However, flexible bronchoscopes cannot completely replace rigid bronchoscopes. When removing sharp objects such as glass, nails, or thumbtacks, flexible bronchoscopes do not protect the airway, whereas rigid bronchoscopes do [63]. Some objects, such as teeth, are not removable with tools available for flexible bronchoscopes [7780]. There are no randomized controlled trials comparing rigid and flexible bronchoscopy to guide the practice, but they can be used complementarily [818283].

In general, foreign body aspirations at dental clinics can be managed using bronchoscopy [59]. Fortunate cases, with spontaneous expulsion after impaction, have been reported [848586], but most cases require further management, usually with bronchoscopes. Both rigid and flexible bronchoscopes have been used for management [5878889]. In a few cases, surgical resection was performed after unsuccessful interventions [289091]. It is unclear whether rigid or flexible bronchoscopy is more suitable for patients with foreign body obstruction in dental practice. The nature and location of the object and the expertise of the medical center are decisive factors.

3. Anesthesia during bronchoscopy

Flexible bronchoscopy in adults is often performed under moderate sedation under monitored anesthesia [92]. Topical anesthesia is applied to the oropharynx and laryngopharynx using a spray gargle or gel [93]. Under a condition of conscious sedation, foreign bodies can be extracted via the mouth without positive pressure or jet ventilation [63]. A British Thoracic Society guideline recommends a combination of benzodiazepines and opioids during flexible bronchoscopy, with midazolam and fentanyl as the preferred drugs [93]. Other available medications include remifentanil [94], propofol [95], ketamine [96], and dexmedetomidine [97]. They can be administered by a bronchoscopist or anesthesiologist [9899100].

Rigid bronchoscopy requires deep sedation because the procedure is stimulating and uncomfortable for patients [92101]. Total intravenous anesthesia with propofol and remifentanil can be used effectively and safely. As in flexible bronchoscopy, dexmedetomidine and ketamine are alternatives [92]. Ventilation techniques for rigid bronchoscopy are a cause for concern, as optimal ventilation must be achieved during airway procedures. Positive-pressure ventilation and jet ventilation have been applied [92101]. For children, since rigid bronchoscopy is still considered the first choice for the management of foreign bodies, procedures under general anesthesia are frequent. Sevoflurane can be used in children for induction and maintenance, as it provides more stable hemodynamics and respiration, as well as faster induction and recovery [102]. Alternatively, total intravenous anesthesia with propofol and remifentanil can be used in children [103104].

PREVENTIONS IN DENTAL CLINICS

Prevention of accidental aspiration during dental procedures has been emphasized [9105]. Although accidents may occur at any time, procedures considered higher-risk include periodontal treatment, direct restorative treatment, indirect restorative treatment, removable prosthodontic treatment, and endodontics [106]. Other potential risk factors include decreased gag reflex in the elderly and patients with neurologic conditions and an altered state of consciousness [107]. These situations warrant a higher level of attention to the possibility of inhalation accidents, and barrier techniques can be used. Dental equipment must be checked periodically to ensure that the handpieces hold burs securely and that other small objects are affixed securely. Rubber dams are known to be the easiest and most effective method of preventing aspiration and ingestion [9]. Rubber dams have been used for more than 150 years and have the additional benefits of reducing microbial contamination, enhancing visibility, improving visual access to the canal, optimizing moisture control, and retracting soft tissues. Despite these advantages, the use of rubber dams is often overlooked because it is perceived as difficult and time-consuming by practitioners, who also think patients do not like it. However, several reports show patient satisfaction with the use of rubber dams, and their application needs to be encouraged [108]. In cases where a rubber dam cannot be applied, such as in orthodontic, prosthodontic, and various microsurgical procedures, a gauze screen (4 × 4 inches) can be used to block the access of objects into the oropharynx [9]. The gauze itself can also be aspirated; it can be controlled by attaching a floss or by leaving a long trailing edge of the gauze [107]. Nonetheless, gauze screens may not be tolerated in some cases owing to gag reflexes or the limited space available for procedures with enlarged tongues [9109]. Such cases should avoid alignment of the oral cavity and laryngopharynx in a straight line during the procedure [9110]. If the patient is in a straight position, an object dropped into the pharynx may not cause a gag reflex or foreign body sensation. The head rest and chair can be adjusted to the upright or reverse Trendelenburg position [8]. A dental floss or ligature wire can be tied to avoid the incidence. Handles for hex drivers are also available. A lip retractor with a magnet has also been devised to maintain mouth tissue retraction and to magnetically attach accidentally dropped instruments [111].

PROGNOSIS OF DENTAL FOREIGN BODY ASPIRATION

The reported treatment success rate for dental foreign body aspiration is high. A review of reported cases from 1974 to 2014 found that 16 of 20 patients (80.0%) had a successful endoscopic retrieval, three (15.0%) had a lung resection, and one (5.0%) had spontaneous excretion [5]. However, there are reports of morbidity and mortality [826]. Kim et al. reported a patient aged > 90 years who had tooth #14 extracted. During the process, the gold crown of the tooth was aspirated, and, despite transfer to the emergency room and successful bronchoscopic removal, the patient deteriorated and died after intensive care [8].

Delayed recognition and management can result in pulmonary complications. Pneumonia and abscesses can develop, causing respiratory symptoms, such as cough, sputum, and dyspnea [3]. In severe cases, chest infections can lead to sepsis [112]. A tooth impacted in the main bronchus has been reported to cause air trapping and respiratory failure, acting as a ball valve allowing air to enter during inspiration, but occluding during expiration [113]. Other possible serious complications of foreign bodies in the airway include pneumothorax, atelectasis, bronchiectasis, hemorrhage, and bronchoesophageal fistula [939].

CONCLUSION

The aspiration of objects related to dental practices can occur. Such patients require urgent attention and should be referred to healthcare facilities, where further evaluations can be performed. The mainstay of treatment is bronchoscopy; in some cases, surgical resection of the lung is required. Missed foreign bodies in the airways can cause further pulmonary complications.