Fixed prosthodontic therapy had the highest number of incidents of adverse outcomes.

Examination of aspiration and ingestion incidents is difficult, owing to the scarcity of documented instances. No long-term evaluation of these events in a multidisciplinary environment has been reported.

When considering the potential complications of aspiration versus ingestion, the intuitive conclusion would be that aspiration would have a higher morbidity rate than ingestion. However, the potential for morbidity in ingestion cases is present in cases of impaction of dental prostheses (such as dentures caught in the cervical esophagus) and the major surgery patients sometimes have to undergo to have the prostheses removed. Authors have noted that the second most likely object to be aspirated is dental in origin.^1–8 The occurrence of an aspiration demands that a careful clinical examination be conducted and that it include obtaining radiographic studies to document the presence or absence of the object. Because of the potential harm to patients from aspirations or ingestions that go undetected, radiographs are the only diagnostic tool available to rule out ingestion or aspiration of a dental foreign object.⁹ Bronchoscopy and esophagoscopy are the mainstays of foreign object retrieval in the upper airway and aerodigestive tract, though certain anatomical limitations require the use of surgical techniques involving the patient’s neck, chest or abdomen to remove foreign objects.¹ In addition, immediate complications such as acute airway obstruction and hypoxia and chronic complications such as esophageal erosion and pneumonia resulting from unrecognized aspiration or ingestion are serious medical issues that require further care and hospitalization.¹ These complications not only have associated economic cost, but also carry the risk of malpractice litigation against the dentist.¹ Use of rubber dams and gauze throat screens probably has reduced the number of these adverse events.^1,10 However, physical barrier methods alone do not completely prevent aspiration or ingestion.

There were 36 reports of aspiration or ingestion during the 10-year study interval.

We conducted this study because we believed that a closer examination of the circumstances surrounding aspiration and ingestion of dental foreign objects was warranted. We wanted to evaluate appropriately the risk of aspiration or ingestion during certain dental procedures and identify those groups of patients who have a higher likelihood for aspiration and ingestion of dental instruments or dental materials.

	METHODS

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
We conducted a retrospective review of dental charts and medical records at the School of Dentistry, The University of North Carolina at Chapel Hill, during a 10-year period (1992–2002). The practice areas we studied were faculty dental practice, graduate/resident dental practice, undergraduate dental practice, and dental hygiene undergraduate and graduate practice. The specialties we studied were prosthodontics, endodontics, periodontics, oral and maxillofacial surgery, pediatric dentistry, oral radiology and orthodontics. We included all facets of general dentistry and dental hygiene.

Our inclusion criteria involved all patients who were documented to have loss of dental instruments or material behind the posterior pharynx during a 10-year consecutive period. We excluded from our review patients who had aspirated or ingested dental foreign objects during dental procedures performed elsewhere than the university and those who received dental care under general anesthesia in a hospital environment.

We grouped the patients into three categories:

– patients who had a documented instance of aspiration in conjunction with dental therapy;

– patients who had documented ingestion of dental foreign objects related to the procedure being performed;

– patients who, while initially reported to have aspirated or ingested dental objects, were not found to have ingested or aspirated dental objects on routine radiographic examination, and those patients in whom the dental object either was located in the mouth at a later time or was located outside of the mouth.

We then categorized the events of aspiration, ingestion or neither by specialty and analyzed them.

We compared the number of patient visits during the 10-year interval—which were 100,000 per year on average—with the actual number of documented instances of aspiration or ingestion and found them to be statistically insignificant on routine analysis.

	RESULTS

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
There were 36 reports of aspiration or ingestion during the 10-year interval. Of these, only one case involved aspiration of a cast post and core (Figure 1). Twenty-five patients ingested a dental foreign object (Figure 2). The remaining 10 patients reported having aspirated or ingested a dental foreign object, but the objects were not revealed on radiographs, or the objects were recovered outside or inside the patients’ mouths.

View larger version (125K): [in this window] [in a new window]   Figure 1. Aspirated post and core (arrow) in the patient’s right lung.

View larger version (49K): [in this window] [in a new window]   Figure 2. Dental instruments with pieces broken off that were ingested.

View larger version (156K): [in this window] [in a new window]   Figure 3. Ingested ultrasonic scaler tip (arrow) in the patient’s large intestine.

View larger version (27K): [in this window] [in a new window]   Figure 4. Number of incidents by specialty department. The "Other" category comprises the 10 cases in which no object was aspirated or ingested.

	DISCUSSION

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
Aspiration or ingestion occurred most commonly in procedures involving fixed prosthodontic therapy—specifically those involving cementation of permanent crowns—and adjunctive procedures such as placement of cast post and core and onlays and implant-related procedures. The higher occurrence of aspiration and ingestion could be attributed to the likely absence of rubber dams in the patients’ mouths during the cementation of crowns and implant procedures. This has obvious implications in occurrences of dislodgement. During cementation the crown is "wet" from the cement applied to its undersurface, which makes it difficult to grasp and retrieve should it fall in the patient’s mouth. Another explanation may be related to the number of times a crown has to be removed, adjusted and replaced in the patient’s mouth before actual cementation. This would increase the relative risk of an adverse event’s occurring, as the crown may be dropped or dislodged and fall into the patient’s posterior pharynx during adjustment.

One interesting finding of our study was that none of the patients had received local anesthetic before undergoing the dental procedure. This is in clear opposition to the long-held belief that anesthetized patients would be more likely to swallow or aspirate dental foreign objects during procedures, owing to the relatively decreased sensory input from their oral cavities.¹¹

There is a relatively infrequent occurrence of adverse outcomes in the special care and pediatric populations. This finding contradicts the widely held belief that these patients are at high risk of aspirating or ingesting dental foreign objects because of their higher likelihood of having a neuromuscular disease or a physical handicap. These conditions can diminish the patients’ protective airway reflexes, resulting in their having difficulty following verbal commands from the dentist.¹² It also is possible that these patients have a lower likelihood of receiving fixed prosthodontic treatment in which cast dental restorations are used.

One of the most important findings of our study is the relative infrequency of aspirations and ingestions, considering the large number of patients seen at the School of Dentistry, The University of North Carolina at Chapel Hill, where the majority of the practitioners are novices in terms of their years of dental practice experience. However, this also could be a result of attending dentists’ being present and the slower pace at which dental therapy is performed.

Aspiration or ingestion is an infrequent occurrence, and ingestion occurs more often.¹³ This may be a direct result of the strong coughing that occurs when there is a foreign object in the patient’s airway, which makes it more difficult for aspiration to occur.¹³ When we examined the radiographs from the 36 cases, we found that 10 were negative for aspiration or ingestion of dental foreign objects. This is a direct result of the strict institutional policy of reporting all cases, including suspected cases. These cases often involved instruments that were broken or went missing during dental therapy.

	CONCLUSIONS

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
The health care implication of adverse events such as aspiration or ingestion of dental foreign objects during dental therapy is large. While these events occur infrequently, the potential morbidity associated with a single incident is too high to ignore. This is especially true from the standpoint of the amount of medical care needed to manage these incidents, the high financial cost to the dentist and the potential for malpractice litigation.⁹

This potential morbidity is even more important when one considers that aspiration and ingestion are preventable. Our data support the idea that aspiration or ingestion is more likely related to the type of restoration being completed on the patient, specifically in circumstances in which fixed prosthodontic therapy is involved. Dentists should use rubber dams routinely instead of cotton roll isolation to prevent the patient from aspirating or ingesting dental foreign objects. Using a gauze throat screen to catch objects before they fall into the patient’s posterior pharynx is another method of preventing aspiration or ingestion in cases in which a rubber dam is not warranted.¹¹ Tethering small instruments or clasps with floss is yet another way to prevent aspiration or ingestion of foreign objects.¹¹ Ulusoy and Toksavul¹⁴ recommend an innovative technique that involves adding a V-shaped loop to all castings to tether floss, which would help during the try-in phases for fixed prostheses. Aspiration and ingestion are more likely to occur in this type of situation, and patients should not be reclined as far back in the chair as they are during other procedures.¹

Dentistry has done an excellent job of minimizing adverse outcomes resulting from aspiration or ingestion by using gauze throat screens and rubber dams.¹³ One patient who aspirates or ingests dental foreign objects is one patient too many; these incidents are preventable if the correct precautions are taken.

View larger version (135K): [in this window] [in a new window]   Dr. Karen Tiwana is an assistant professor and the director of urgent care, Department of Diagnostic Sciences and General Dentistry, School of Dentistry, 180 Dental Office Building, The University of North Carolina at Chapel Hill, Chapel Hill, N.C., 27599-7450, e-mail "karen_tiwana{at}dentistry.unc.edu". Address reprint requests to Dr. Karen Tiwana.

View larger version (156K): [in this window] [in a new window]   Ms. Morton is an assistant professor and the director of risk management, Department of Diagnostic Sciences and General Dentistry, School of Dentistry, The University of North Carolina at Chapel Hill.

View larger version (137K): [in this window] [in a new window]   Dr. Paul Tiwana was a visiting clinical professor, Department of Oral and Maxillofacial Surgery, School of Dentistry and the University of North Carolina Hospitals, The University of North Carolina at Chapel Hill, when this article was written. He now is completing a one-year oral and maxillofacial surgery fellowship in pediatric craniofacial surgery, Chevy Chase, Md.