A New Philosophy for the Treatment of Avulsed Teeth

The treatment of avulsed teeth is a true emergency, perhaps the only true emergency that confronts a dentist. Although studies have estimated the success rate of reimplanted avulsed teeth to be between 10% to 90%,^1-3 the real success rate is difficult to determine, because they occur as a result of accidents and, therefore, no real controlled studies on humans can be performed.

Clinical research has shown that the success of reimplanted avulsed teeth that are stored in an optimal storage environment (OSE) can be as high as 91%.³ The potential for success has increased due to new treatment advances derived from extensive in vitro cell culture⁴ and animal research^5-7 and the introduction of OSEs to the armamentarium.⁸ Yet, although the possibility of high success rates of reimplanted avulsed teeth has been demonstrated, there still remains a belief that it is a temporary measure at best or even a waste of time.

In a socioeconomic study of avulsed tooth treatment, all of the costs of reimplanting an avulsed tooth were weighed, and it was determined that the cost was very high and possibly not worth the money spent.⁹ In an informal survey at the most recent American Association of Oral and Maxillofacial Surgeons meeting, 50% of those surveyed thought reimplantation was a procedure that eventually resulted in failure.¹⁰ However—considering the monumental dental consequences of losing anterior teeth in children between the ages of 6 and 18—the opinion of most dentists is that avulsed teeth should be reimplanted to maintain the facial bone, at least until facial growth is complete.¹¹

While dentists believe that reimplantation is an important and necessary procedure and dental research has shown that avulsed teeth can be successfully reimplanted and saved for life, the success rate is not considered to be very high and—among some pragmatists—it is deemed a waste of a patient’s time and money.

So where is the disconnect? The primary cause is related to many factors, among them: the phenomenon of “cognitive dissonance,” which describes the discomfort caused by holding conflicting ideas simultaneously; and a lack of proactive education of and recommendation to patients by dentists about how to prepare for this type of dental emergency. This leads to the occurrence of cognitive dissonance’s related phenomenon, the “self-fulfilling prophesy.”

This article first addresses the biology of and the newest treatment recommendations for avulsed teeth. It then discusses the methodology for dramatically increasing the success rate of avulsed treatment with what the author terms “preventive traumatology.”

Treatment of Avulsed Teeth

Biologic Rationale for Treatment Recommendations

Research has shown that there are three factors that contribute to the success of reimplanted avulsed teeth:

• The physiologic status of the remaining periodontal ligament (PDL) cells on the root surface.^12,13
• The status of the maturity of the root apex.^14,15
• The length of extraoral time.^16-18

Physiologic Status of the Root PDL Cells

The physiologic status of the PDL cells remaining on the root surface of an avulsed tooth at the moment of reimplantation determines the development of replacement resorption.^11,19 If the PDL cells are physiologically and morphologically intact at the moment of reimplantation, a new attachment to the surrounding alveolar bone is possible with a minimum of external root resorption.¹¹

In order for optimum physiologic conditions to be maintained, the PDL cells need a continual re-infusion of metabolic nutrients such as glucose, cations such as potassium and chloride, a compatible osmolality (280 mOs to 320 mOs), and a proper pH (6.8 to 7.2).⁴ (Note: Osmolality is the concentration of the solution. In a PDL cell, it measures the pressure that the internal contents of the cell exert against the cell membrane.) The laws of physics hold that when an area of high concentration is pushed to an area of low concentration, the higher osmolality of 280 of the PDL cell will cause the cell contents to push against the cell membrane. For proper physiology and morphology to be maintained, the cells need to be stored in an appropriate supportive fluid medium4 and must be protected from physical crushing damage.^11,19,20 If the PDL cells are diminished metabolically or morphologically, the root cementum will necrose, a new PDL will not form, and replacement resorption will occur.¹¹

Research has shown that the recommendation of keeping the avulsed teeth “wet” during transport to the dentist is a misunderstanding of what is really necessary to maintain cell vitality.¹⁹ In fact, placing avulsed teeth in tap water will kill the root PDL cells.^4,11 Likewise, storage in saliva—although “wet”—will kill PDL cells.⁴ The damage these fluids cause is due to their incompatible osmolality or concentration with the root PDL cells.¹⁹ Tap water has an osmolality of 17 mOs and saliva has an osmolality of 34 mOs. Because a normal PDL cell has an osmolality of 280 mOs, placing the avulsed tooth in either of these mediums will cause the root PDL cells to burst and necrose, thus leading to unstoppable replacement resorption and either ankylosis or tooth loss. Even milk, which has received much attention in dental academia and has been recommended via the press to the public, does not have the ability to replace lost nutrients and has a less than optimal osmolality of 230 mOs.^4,19 Although not destructive like water or saliva, cells stored in milk do not have the ability to mitose.²¹ The only fluid that has clearly shown beneficial effects in preserving root cell viability is a pH-balanced cell-reconstituting medium such as Hank’s Balanced Salt Solution (HBSS) from Life Technologies™ (www.lifetechnologies.com).^4,5,11 (Note: Hank’s Balanced Salt Solution is a pH-balanced cell-preserving fluid. It is not a salt-water solution; it contains: sodium chloride, d-glucose, potassium chloride, sodium bicarbonate, sodium phosphate, potassium phosphate, calcium chloride [monobasic], and magnesium sulfate [anhydrous].) It maintains the ideal osmotic pressure for PDL cells and replaces depleted cell metabolites.⁴ Significant success rates of reimplanted avulsed teeth can be achieved if they are placed within 60 minutes of the accident and stored in an OSE containing HBSS, such as the Save-A-Tooth^® (Phoenix-Lazerus, Inc., www.saveatooth.com) 3 system or e.m.t™ TOOTHSAVER (SmartPractice, www.smartpractice.com), which has a different non-HBSS cell-preserving solution.

Because an avulsed tooth is cut off from its blood supply, its root PDL cells will begin to use their stored metabolites almost immediately. Within 15 minutes, these cells will begin to necrose and they all will be almost completely necrotic within 60 minutes. The best chance of success following the reimplantation of the avulsed tooth occurs when the maximum number of healthy, physiologically sound PDL cells are present; therefore, teeth that have been extraoral for 15 minutes or more should not be reimplanted immediately, but should be soaked in HBSS for 30 minutes prior to reimplantation.^22,23 Research has shown that avulsed teeth that have been dry for 60 minutes can have partially degenerated PDL cells reconstituted.²⁴ These PDL cells are better able to form a new PDL.

Much of the confusion about which medium should be used to store avulsed teeth while they are being transported to the dentist arises from a misunderstanding about this fundamental biologic condition. The overriding decision for selection of the medium should be based on which medium preserves the metabolic and physiologic status of the root PDL cells best. A thorough discussion of the research studies regarding storage media for avulsed teeth can be found in a 1994 article by Krasner and Rankow. For the purposes of this article, it is sufficient to state that there is universal agreement among dental traumatologists that the best storage medium now available is an HBSS-type solution.¹¹

Status of the Development of the Root Apex

In certain instances, it is possible to completely revascularize the pulp of avulsed teeth in immature avulsed teeth. Researchers differ in their opinion on which factors—including width of the apical foramen, duration of the extra-alveolar time, and storage conditions—most influence the incidence of revascularization. However, there appears to be universal agreement that contamination with microorganisms can prevent revascularization of the pulp.²⁵ Therefore, soaking immature apexed avulsed teeth in a 1-mg/20-mL solution of topical doxycycline for 5 minutes prior to reimplantation has been shown to decrease root resorption and, more significantly, to increase the rate of pulpal revascularization to 41%.25 Reimplanted immature apexed teeth need to be monitored weekly during the first 30 days for signs of pulpal revascularization and replacement or inflammatory root resorption. If there are signs of resorption or the tooth becomes symptomatic, the pulp should be extirpated immediately and normal apexification or apexogenesis procedures instituted.²⁶

Length of Extraoral Time

By far, the most extensive research has been done on the length of time teeth have been extraoral and the resulting consequences. However, the length of extraoral time is less important than the actual status of the cells remaining on the root surface at the time of reimplantation. Avulsed teeth can be extraoral for as long as 24 hours, as long as they are stored in a pH-balanced fluid such as HBSS, which provides the optimum biologic support for root PDL cell metabolism.^5,7 Some research has shown that avulsed teeth can be stored for weeks in a suitable enriched medium and still be successfully reimplanted without much root resorption occurring.²⁷

Clinical Treatment of Avulsed Teeth

Successful long-term retention of reimplanted avulsed teeth is dependent on a wide range of factors—from the handling of the PDL cells, use of a biologic storage medium, maintenance of PDL cell vitality, timing of pulp extirpation, to the type and duration of splinting. Every step in this process is critical, and the final success of the reimplanted tooth is only as successful as the quality of the treatment rendered at each step. As in every chain, the success of the reimplanted avulsed tooth is only as successful as its weakest link.

The entire reimplantation treatment of avulsed teeth can be divided into three stages: the pre-reimplantation stage, the reimplantation stage, and the post-reimplantation stage.

Pre-Reimplantation Stage

Under normal conditions, a tooth is attached to the alveolar bone socket by the periodontal ligament. Through the ligament, the cells of the root cementum obtain their nutrition through the blood supply contained within the PDL. The PDL cells—like any other cell in the body that remains on the root after the avulsion—are cut off from their blood supply and begin to immediately deplete their stored cell metabolites. To maintain optimal cell metabolism, these depleted cell metabolites must be replaced within 60 minutes after the avulsion; otherwise the PDL cells will undergo necrosis. In addition, the cells of the root PDL are very delicate and must be protected from being crushed. This leads to the admonition to dental traumatologists, which is found in textbooks, that the root of an avulsed tooth should not be touched.

Although the best treatment for avulsed teeth is immediate reimplantation, this is often not done for a variety of reasons, such as:

• The people at the scene of the accident will not do it.²⁸
• The people at the scene of the accident are not dentists and, if multiple teeth are avulsed, they will not know which tooth goes into which socket.
• The accident victim may have more serious injuries—eg, a punctured lung— that require primary treatment.
• The accident victim may be hysterical, unconscious, or otherwise uncooperative.
• There may be severe lacerations in the area of avulsion, the bleeding of which prevents visualization of the reimplantation site.

Hamilton et al²⁸ showed that 80% of the people at the scene of the avulsion will not touch the avulsed teeth and perform the reimplantation. It is therefore clear that immediate reimplantation is an idealistic recommendation that will not be performed in at least 80% of the cases. Therefore, the second, and more probable and practical choice, is transportation to a dentist in a biologic, protective method that contains a biologically supportive medium.^11,26

Reimplantation Stage

Avulsed teeth present at the dental office in eight basic categories, and only those in category 1 benefit from immediate reimplantation. The other seven categories are better treated with various other types of pre-reimplantation conditioning (see Table 1).

Teeth that have been extraorally for 15 minutes or more should not be reimplanted immediately, but should be soaked in HBSS for 30 minutes before reimplantation.²³ Research has shown that avulsed teeth that have been dry for 60 minutes can have partially degenerated PDL cells reconstituted.²³ These PDL cells are better able to form a new PDL. Even if the teeth are stored in saline or milk from the time of the avulsion, the teeth should be soaked in HBSS for 30 minutes before reimplantation.¹⁹

Avulsed teeth with immature roots present a different set of clinical conditions. These teeth—while still subject to the same root resorption problems—possess the potential for pulpal revascularization. Therefore, these teeth must be treated differently than closed-apexed teeth. These teeth should be soaked in a 1-mg/20-mL doxycycline solution prior to reimplantation.^11,23 and monitored weekly for signs of pulpal revascularization or inflammatory root resorption. If there are signs of resorption, the pulp should be extirpated immediately and normal apexification procedures instituted.²⁰

Even teeth that have been extraoral and dry-stored for long periods of time should be reimplanted. Because the PDL cells are necrotic, the root surface should be treated in such a manner as to slow down the inevitable root resorption.¹¹ The root surface should not be scraped in order to leave as much cementum as possible.¹¹ In addition, the teeth should be soaked in sodium hypochlorite to remove the remaining PDL. The root canal should be fully instrumented.¹¹ The tooth should be soaked in a 2% stannous fluoride solution for 5 minutes, and the root canal should be obturated.¹¹ Corticosteroids placed in the root canal may slow the resorptive process.¹¹ Soaking the avulsed teeth in Emdogain^® (Straumann USA, www.straumann.us) is very controversial and may or may not help to stimulate the formation of new PDL.^26,27

Additionally, researchers recommend against touching the root surface of an avulsed tooth in categories 1 through 6; crushing damage to the root PDL cells of an avulsed tooth has been shown to cause severe root resorption after reimplantation.²⁸ Atraumatically retrieving an avulsed tooth from a transportation container is more troublesome than most practitioners realize. Dirt on an avulsed tooth picked up from an accident site could make the storage medium murky and milk is naturally opaque, and containers may have very small openings. All of these factors make retrieving the avulsed tooth very difficult and may cause crushing of the root PDL cells as the dentist struggles with fingers or forceps to grasp the avulsed tooth. The optimal storage device should possess a removable basket that permits atraumatic transport, washing of debris, and atraumatic retrieval of the avulsed tooth while additionally permitting the preservation of the HBSS for additional use during reimplantation if socket modification is necessary. The use of optimal storage devices is now considered the standard of care and is recommended for use by dentists, ambulances, emergency rooms, and at home by most textbooks.^11,26

Before reimplantation, a radiograph is taken to rule out the presence of a root tip or foreign body in the socket. The tooth should be placed in a physiologic fluid so that any debris can be soaked away from the PDL; placement in HBSS will also permit a reconstitution of the cell metabolites. The socket is gently irrigated with sterile water, saline, or anesthetic solution. If a clot is observed in the socket, it can be gently curetted out.

The avulsed tooth is grasped by the clinical crown and inserted into the socket. Steady gentle pressure should then be exerted in an apical direction; it may take as long as 30 to 60 seconds to seat the tooth completely. If the tooth will not seat completely, it should be removed and curetted and the socket should be irrigated again. Under no circumstances should the apex of the avulsed tooth be cut off. The most recent research has shown that there are viable stem cells at the apex that can be stimulated during endodontic treatment to form new apical tooth structure.²⁹ If the avulsed tooth does not seat completely, it should be removed from the socket, placed back in a HBSS, and the socket modified to permit a complete seating of the tooth. Studies have shown that the modification of the socket has very little influence on the ultimate success of the reimplanted avulsed tooth.^30,31

When the avulsed tooth is seated completely in place, it must be splinted. There are a variety of splints that can be used, but all types should be physiologically functioning.¹¹ The splint should hold the tooth firmly in position while allowing slight movement and should stay in place for a maximum of 2 weeks.¹¹ The best type of splint is orthodontic bracketing with a .06 wire on the avulsed tooth and on the teeth mesial and distal to it.

Occlusion should be checked to make sure that excessive pressure is not being exerted on the reimplanted splinted tooth. In addition, a radiograph with the avulsed tooth splinted into position should be taken to ensure proper placement. No endodontic treatment should be instituted at this time except for Category 4 and Category 8.¹¹ The patient should be prescribed a systemic antibiotic such as amoxicillin clavulanate 250 mg four times per day for 7 to 10 days, a chlorhexidine rinse twice a day for 2 weeks, and an appropriate analgesic such as ibuprofen 600 mg or hydrocodone 7.5 mg every 4 hours.¹¹ In addition, a recommendation for a tetanus prophylaxis injection should be made.¹¹

Because treatment of a patient with tooth avulsion is always an emergency, a tray should be prepared ahead with the following items: a doxycycline capsule (100 mg); orthodontic wire and brackets; light-cured composite; a 5-cc irrigating syringe; a long-necked spoon excavator; stannous fluoride; and a storage device for avulsed teeth, such as Save-a-Tooth or e.m.t TOOTHSAVER. It would also be helpful to have a description of the categories of avulsed teeth with this tray.

Post-Reimplantation Stage

The patient should return 7 to 10 days after the reimplantation. At this appointment, the splint is checked for integrity and patient is anesthetized with local anesthesia. The pulp is extirpated and the canal system cleaned and shaped in the usual fashion.²⁰ A calcium-hydroxide mixture is placed in the canal.¹¹ After 1 month, the calcium hydroxide should be removed and the canal should be instrumented and obturated.

Discussion

Thirty years ago, the recommendation to patients for the management of avulsed teeth was a simple, “one-size-fits-all” approach: retrieve the teeth, wash them off, and push them back into their sockets. If that is not possible, the patient should drop them in a cup of milk and get to the dentist as quickly as possible.

For dentists, too, 30 years ago it was just as much a one-size-fits-all approach: They would remove teeth from the transportation device, do the endodontics in their hand, reimplant the teeth and splint them into place, prepare the patient’s parents for eventual failure, and hope that the resorption would leave the clinical crown in place until the patient was 18.

Now the task for dentists is much more complicated. As shown above, there are eight different clinical categories in which an avulsed tooth may present to a dentist. Each of these requires a separate treatment regimen. Dentists are not taught this in school, and they have to learn a new technique for which insurance companies have no sympathy.

It is clear that there are four equally important aspects that dentists need to institute in order to maximize the success rate of reimplanted avulsed teeth:

1. Educate the general population that avulsed teeth can be saved.
2. Recommend to patients and the general population that they should be prepared for this type of accident by having suitable optimal storage devices readily available where accidents can occur.
3. Dentists should diagnose the condition of each avulsed tooth and use the most biologically compatible technique for treating avulsed teeth in their offices.
4. The reimplanting professional must recommend that endodontic therapy be instituted at the appropriate time after reimplantation.

The past strategies for managing accidental avulsion (ie, reimplant at the scene of the accident or place the teeth in a non-damaging medium such as milk) need to be revised. The use of milk as a storage medium, although appealing and far better than tap water or saliva, is, upon careful examination, a poor choice for the following reasons:

1. It is often not available at accident scenes such as automobile accidents, sports playing fields, hospital operating rooms, schools, and playgrounds.
2. It is not the most biologically supportive medium.^4,5,7
3. It has a short supportive time (1 to 3 hours).^4,5,7
4. It has a poor PDL cell vitality maintenance.^4,21
5. It does not promote cell mitosis.²¹
6. It does not protect against crushing of the delicate PDL cells.

To continue to promote milk as the best storage medium for avulsed teeth is to deny the public of the benefit of extensive research that has shown that there are far better methods to save children’s or adults’ avulsed teeth.

From the above research, it is apparent that the manner in which the avulsed teeth are treated within the first 15 to 60 minutes after the accident determines the ultimate success of the reimplanted avulsed tooth.

To truly increase the success of reimplanted avulsed teeth, a new proactive activity on the part of dentists must be undertaken. It was such “preventive traumatology” that investigated and very successfully promoted the use of mouthguards. The literature on this topic is very extensive and it is now accepted that every sports program should require the use of mouthguards.

However, most people do not wear mouthguards in their daily life. Most children do not wear them while playing on jungle gyms in playgrounds and most adults do not wear them while driving their cars. The reality is that teeth get knocked out during accidents that occur in the process of many daily activities.

Therefore, dentists must take the same approach as physicians and pediatric allergists. They need to advise their patients, parents, school nurses, athletic trainers, and first responders that in order to be prepared for a tooth avulsion accident, they should have optimal storage devices in their first aid kits ahead of time. If they are used within 1 hour of the accident, the patient has 24 hours to find a dentist who can reimplant them in the proper position. If they are used within 1 hour, over 90% of reimplanted avulsed teeth can be saved, if not for life, then at least until patients are 18.

This should be an easy task for dentists. They do it every day when they promote brushing, flossing, regular cleanings and examinations, and caries-reduction diets. It is in the best interests of the patient to recommend the inclusion of an avulsed tooth-preserving system at home, at their child’s schools, in their child’s sport first-aid kits, in ambulances, and in their car first-aid kits. This is what is meant by “preventive traumatology.”

This is where the mindset of the dentist has to change. Even though nearly all dentists consider the loss of four anterior teeth in an 8-year-old to be devastating, due to past poor results following reimplantation of avulsed teeth, they often neglect to educate people about a far more effective way to prepare for an avulsion accident and, thereby, maximize the success of reimplanted avulsed teeth. They need to realize the poor results observed in the past were a direct result of the method used. Placing the avulsed teeth in milk is no longer a professionally responsible recommendation now that it is possible to have on hand an optimal storage device.

Conclusion

Research and clinical studies have demonstrated that the reimplantation of avulsed teeth can be a successful procedure with excellent long-term retention of over 90%. However, this success can only become a clinical reality by the application of new treatment regimens and with a concerted, coordinated education program—ie, preventive traumatology—by dentistry to advise the general population to be prepared ahead of time for this type of accident by purchasing avulsed optimal storage devices ahead of time. With the adoption of these strategies, the incidence of long-term retention of avulsed teeth can be significantly improved.

Disclosure

Dr. Paul Krasner is part owner of Phoenix-Lazerus, Inc., which manufactures the Save-A-Tooth system.

References

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About the Author

Paul Krasner, DDS
Professor
Department of Endodontology
Temple University School of Dentistry
Philadelphia, Pennsylvania