Dental avulsion is the complete displacement of a tooth from its socket in alveolar bone owing to trauma, such as can be caused by a fall, road traffic accident, assault, sports, or occupational injury.

[3] Avulsions of primary teeth are more common in young children as they learn to move independently (walk and run) and also from child abuse.

Pulp necrosis with draining fistula, crown discoloration and external root resorption are reported consequences of primary tooth replantation.

Certain occlusal characteristics, such as class II malocclusions with increased overjet, are associated with a higher risk of dental trauma.

The avulsed permanent tooth should be gently but well rinsed with saline, with care taken not to damage the surface of the root which may have living periodontal fiber and cells.

[15] If the tooth cannot be immediately replaced in its socket, follow the directions for any knocked-out (avulsed) teeth kit, or place it in cold milk or saliva and take it to an emergency room or a dentist.

[5] In addition, as recommended in all cases of dental traumas, good oral hygiene with 0.12% chlorhexidine gluconate mouthwash, a soft and cold diet, and avoidance of smoking for several days may provide a favorable condition for periodontal ligaments regeneration.

The clinician should consider the age of the patient, the history of the injury, status of tooth root apex and whether it is in line with clinical findings.

Gentle irrigation with a saline solution, should be performed as this removes any clots within the socket, which could prevent the proper re-positioning of the tooth into its original position.

The torn ligament that stays on the socket wall, since it remains connected to the bone and blood supply, is naturally kept alive.

At the same time that this agitation occurs, the bumping of the tooth root against a hard surface such as glass, plastic or even cardboard must also be avoided.

In addition to the potential damage that the hard surface can cause, glass containers have the added possibility of breakage or leakage of the physiologic storage fluid.

When the tooth is knocked out, this normal blood supply is cut off and within 15 minutes[22] most of the stored metabolites have been depleted and the cells will begin to die.

However, due to various factors such as the condition of the avulsed tooth, patient circumstances, or delay in accessing dental care, immediate replantation might not always be possible.

[1][28][5] In cases where immediate replantation is not feasible, selecting an appropriate storage medium to preserve the viability of the periodontal ligament (PDL) cells becomes paramount.

These cells are essential for the successful reintegration of the tooth into its socket, aiding the healing process and preventing resorption.

The International Association of Dental Traumatology (IADT) guidelines stress the importance of minimizing the tooth's dry time and choosing an effective storage medium to enhance replantation success.

[1][28][5] Universally considered the most preferred storage medium for avulsed teeth, milk's effectiveness is attributed to its pH level and osmolality, which closely resemble the natural conditions necessary for sustaining PDL cell viability.

Milk's widespread availability, combined with its nutritional content, provides an optimal environment that supports the survival of PDL cells during the critical period before replantation.

However, any readily available milk can serve as an effective temporary storage medium, making it a practical choice in emergency situations.

HBSS is distinguished by its balanced pH and osmolality, closely simulating the natural conditions necessary for the survival of periodontal ligament (PDL) cells.

[1] Despite its effectiveness, HBSS is not as commonly available for immediate use as household items like milk, which poses a challenge in emergency dental care situations.

[5] These preparations are specifically designed to replenish lost metabolites, providing an optimal environment for the temporary storage of avulsed teeth and significantly enhancing the prospect of successful replantation.

Recent evidence suggests oral rehydration solutions, propolis, rice water, and even cling film might also be beneficial for preserving cell viability, though further validation is needed.

[28] Saline solution and pure water are discouraged due to their lack of essential nutrients and hypotonic nature, respectively, which can lead to decreased viability of PDL cells.

[5] From a clinical perspective, assessing the condition of the PDL cells is vital, classifying the avulsed tooth into one of three groups before treatment.

[33] If unfavorable healing has occurred, the tooth can last into the medium term for 2-10+ years[30] depending on the speed of bone turnover.

In 1974, Cvek[42] showed that removal of the dental pulp following reimplantation was necessary to prevent resorption of the tooth root.

In 1980, Blomlof[23] showed that storing the periodontal ligament cells in a biocompatible medium could extend the extra oral time to four hours or more.

In 1992, Trope et al.[46] showed that extracted dog's teeth could be stored in Hank's Balanced Solution for up to 96 hours and still maintain significant vitality.