Treatment of knocked-out (avulsed) teeth
Encyclopedia
The Treatment of knocked-out (avulsed
) teeth consists of replantation, immediately if possible.
Immediate replantation insures the best possible prognosis but is not always possible since more serious injuries may be present. Studies have shown that teeth that are protected in a physiologically ideal media can be replanted within 15 minutes to one hour after the accident with good prognosis. The success of delayed replantation depends on the vitality of the cells remaining on the root surface. In normal conditions, a tooth is connected to the socket by means of the periodontal ligament
. When a tooth is knocked-out, that ligament stretches and splits in half. Maintaining the vitality of the cells that remain attached to the root surface is the key to success following replantation. Years ago, it was thought that the key to maintaining root cell vitality was keeping the knocked-out tooth wet thus giving rise to storage media recommendations such as water, the mouth and milk. Recent research has shown that one of the key elements for maintaining vitality is storing the tooth in an environment that closely resembles the original socket environment. This environment is one that has the proper osmolality (cell
pressure), pH, nutritional metabolites and glucose
. There are scientifically designed storage media that provide this environment. These storage media are now available to the consumer in retail products. Use of devices that incorporate the ideal storage media and protective apparatuses have increased the success rate of replanted knocked-out teeth to over 90% when used within sixty minutes of the accident.
Up to 25% of school-aged children and military trainees and fighters experience some kind of dental trauma
each year. The incidence of dental avulsion in school aged children ranges from 0.5 to 16% of all dental trauma. Many of these teeth are knocked-out during school activities
or sport
ing events such as contact sport
s, football
, basketball
, and hockey
.
s advise that the best treatment for an avulsed tooth is immediate replantation, for a variety of reasons this can be difficult for the non-professional person. The teeth are often covered with debris. This debris must be washed off with a physiological solution and not scrubbed. Often multiple teeth are knocked-out and the person will not know which socket an individual tooth belongs to. The injured victim may have other more serious injuries that require more immediate attention or injuries such as a severely lacerated bleeding lip
or gum that prevent easy visualization of the socket. Pain may be severe and the person may resist replantation of the teeth. People may, in light of infectious disease
s (e.g. AIDS
), fear handling the teeth or touching the blood
associated with them. If immediate replantation is not possible, the teeth should be placed in an appropriate storage solution and brought to a dentist who can then replant them. The dentist will clean the socket, wash the teeth if necessary, and replant them into their sockets. He will splint them to non-knocked-out teeth for a maximum of two weeks for teeth with normal alveolar process and bone support. Properly handled, even replantation of periodontally compromised permanent teeth in older patients under good maintenance have been reported, with splinting extending for over 4 weeks due to the reduced support structure for the root due to periodontal disease
. One week to ten days after the replantation, the dental pulps of the replanted teeth should be removed and a root canal
treatment completed within two months.
In addition, as recommended in all dental trauma
s 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.
When a tooth is picked up, it should always be grasped by the enamel on the crown. Finger pressure on the tooth root cells will cause cell crushing. Any attempt to clean off any debris should be avoided. Debris should always be washed off gently with, at the very least, a physiologic saline. Even with the use of a physiologic saline, the “scrubbing” of the tooth root to removed debris must be avoided. When placed in a physiologic solution, the tooth should be gently agitated to permit the cleansing of the tooth root. 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. For the same reasons, the method in which the knocked-out teeth are transported must be carefully selected. Placing the knocked-out teeth in transporting vehicles such as tissues and handkerchiefs can be damaging and transporting them in glass or cardboard containers can also be potentially damaging to the cells. 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. If the glass container does not have a tightly fitting top, then during the transportation, the physiologic storage solution can spill out and the teeth can fall, once again, on the floor and, at the same time, be out of a physiologic environment.
s for years. Once this process starts, it is irreversible and the tooth will eventually fall out. In growing children, this can cause bone development problems because the replacement resorption (also termed ankylosis) attaches the tooth firmly to the jaw bone and stops normal tooth eruption and impedes normal jaw growth.
Research has shown that the critical factor for reduction of the death of the tooth root cells and the subsequent root replacement resorption following reimplantation of knocked-out teeth is maintenance of normal cell physiology
and metabolism
of the cells left on the tooth root while the tooth is out of the socket. In order to maintain this normalcy, the environment in which the teeth are stored must supply the optimum internal cell pressure, cell nutrients and pH.
, ice
, saliva
, physiologic saline, milk, pH balanced cell preserving fluids, or under an armpit if no milk is available. Water and ice have been shown to damage the tooth root cells. The osmolality and pH of water and ice is very low (7-17mOs) compared to normal cell pressure (280 mOs). When a knocked-out tooth is placed in water, the cells attempt to equalize with the surrounding environment, the cell fluid tries to move to the outside pressure environment and burst. Water with table salt
in it is damaging to the knocked out teeth.
Saliva, that is placing the tooth under the accident victim’s tongue or in the cheek, has been recommended. Saliva, as a storage media, causes twice damage as water. Its osmolality is very low, causing bursting of the tooth root cells, but additionally, because saliva is filled with its normal flora
of microorganisms, it will severely infect the tooth root cells. When the tooth is replanted, not only will the cells be necrotic but they will also infect the bone socket.
Physiologic saline has a fairly compatible osmolality and will not cause cell structure
swelling but it lacks the metabolites and glucose necessary for maintenance of normal cell metabolism.
Milk has been also recommended as a storage medium for avulsed teeth. Its advantage is the high availability of cold fresh milk.
It was discovered 30 years ago to be less damaging to knocked out teeth than water or saliva. It was recommended because it has a compatible osmolality to tooth root cells and it is thought to be readily available. However, like physiologic saline, it lacks the necessary metabolites and glucose necessary to maintain normal cell metabolism of the tooth root cells. The cells on knocked-out tooth roots in milk do not die immediately but are unable to replicate (mitosis
) and so are less able to reform new cells when replanted.
The most optimum storage media that are available have been shown to be pH balanced cell preserving solutions. The best known and most extensively tested is called Hank’s Balanced Salt Solution (HBSS). It has all of the metabolites such as Ca, P04, K+ and glucose that are necessary to maintain normal cell metabolism for long periods of time. HBSS has been extensively tested in dental and medical research for the past twenty years. This research has shown that 90% of cells stored in HBSS for 24 hours maintain their normal viability and after four days, still have 70%viable. In research studies, extracted dog’s teeth that have been placed in HBSS for four days can still be replanted with little signs of resorption. Hank's Balanced Salt Solution is found in a Save-A-Tooth.
HBSS also has been shown to be capable of replacing lost cell metabolites. Since a cell that has been cut-off from its blood supply depletes its stored metabolites after fifteen minutes, a tooth that has been extra-oral for one hour has less vital cells to reconnect with the bone ligament cells.
Some studies in dental research have shown that knocked out teeth that have been dry for up to one hour will have less resorption if they are soaked in a HBSS for 30 minutes prior to replantation. In these studies, dog’s teeth were extracted and left dry for 30, 45 and 60 minutes and then soaked in HBSS for 30 minutes and then reimplanted. These teeth showed 50% less replacement resorption following reimplantation. It has also been shown that keeping the teeth cold while in the HBSS does not affect success.
Many other types of storage liquids have been tested such as powdered milk
, Enfamil, Gatorade, and contact lens solution. All of them have been shown to either be ineffective or damaging to avulsed tooth.
However, this success rate can only be achieved with the institution of optimum care within fifteen minutes to an hour of the accident. In the case of knocked-out teeth, being prepared and knowing what to do can mean the difference between a person retaining or losing replanted knocked-out teeth for life. Teeth that have been knocked out when they are fully matured, that is, when the root has completely formed, have a much better prognosis than those teeth that are immature and not fully formed. This is due to the fragility of the root. When teeth have not fully formed, the walls of the root are thinner and thus more fragile. Another complication for the prognosis is the length of time that the tooth has been out of its socket. Teeth that are replanted within fifteen minutes of the accident have an excellent prognosis. Teeth that have been extra-oral and dry stored for more than one hour have a poor prognosis. Teeth that have been placed in an optimal storage medium within one hour of the accident also have an excellent prognosis. All teeth that have been knocked out should be replanted but watched carefully for the development of root resorption. Teeth that do not have root canal treatment within two weeks of replantation also have a poor prognosis.
also reported replanting knocked out teeth. Wigoper in 1933 used a cast gold splint to hold reimplanted teeth in place. In 1959, Lenstrup and Skieller declared that the success rate of replanted knocked out teeth should be considered a temporary procedure because the success rate of less than 10% was so poor. In 1966 in a retrospective study, Andresen theorized that 90% of avulsed teeth could be successfully retained if they were replanted within the first 30 minutes of the accident. In 1974, Cvek showed that removal of the dental pulp
following reimplantation was necessary to prevent resorption of the tooth root. In 1974, Cvek showed that storage of knocked out teeth in saline could improve the success of replanted teeth. In 1977, Lindskog et al. showed that the key to retention of the knocked-out teeth was to maintain the vitality of the periodontal ligament. In 1980, Blomlof showed the storing the periodontal ligament cells in a biocompatible medium could extend the extra oral time to four hours or more. He found that the best storage medium was a medical research fluid called Hank’s Balanced Solution. In this study, it was serendipitously discovered that milk could also maintain cell viability for two hours. In 1981, Andreasen showed that crushing of cells on the tooth root could cause death of the cells and lead to resorption and reduction in prognosis. In 1983, Matsson et al. showed that soaking in Hank’s Balanced Solution for thirty minutes prior to reimplantation could revitalize extracted dog’s teeth that were dry for 60 minutes. In 1989, a systematic storage device was developed to optimally store and preserve knocked out teeth. In 1992, Trope et al. showed that extracted dog’s teeth could be stored in Hank’s Balanced Solution for up to 96 hours and still maintain significant vitality. In this study, milk was only able to maintain vitality for two hours.
Dental avulsion
Dental avulsion is the complete displacement of a tooth from its socket in alveolar bone owing to trauma.-Management:Dental avulsion is a real dental emergency in which prompt management effects the prognosis of the tooth...
) teeth consists of replantation, immediately if possible.
Immediate replantation insures the best possible prognosis but is not always possible since more serious injuries may be present. Studies have shown that teeth that are protected in a physiologically ideal media can be replanted within 15 minutes to one hour after the accident with good prognosis. The success of delayed replantation depends on the vitality of the cells remaining on the root surface. In normal conditions, a tooth is connected to the socket by means of the periodontal ligament
Periodontal ligament
The periodontal fiber or periodontal ligament, commonly abbreviated as the PDL, is a group of specialized connective tissue fibers that essentially attach a tooth to the alveolar bone within which it sits...
. When a tooth is knocked-out, that ligament stretches and splits in half. Maintaining the vitality of the cells that remain attached to the root surface is the key to success following replantation. Years ago, it was thought that the key to maintaining root cell vitality was keeping the knocked-out tooth wet thus giving rise to storage media recommendations such as water, the mouth and milk. Recent research has shown that one of the key elements for maintaining vitality is storing the tooth in an environment that closely resembles the original socket environment. This environment is one that has the proper osmolality (cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
pressure), pH, nutritional metabolites and glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
. There are scientifically designed storage media that provide this environment. These storage media are now available to the consumer in retail products. Use of devices that incorporate the ideal storage media and protective apparatuses have increased the success rate of replanted knocked-out teeth to over 90% when used within sixty minutes of the accident.
Incidence
Research has shown that there are five million teeth knocked-out each year in the United States.Up to 25% of school-aged children and military trainees and fighters experience some kind of dental trauma
Dental trauma
Dental trauma refers to trauma to the face, mouth, and especially the teeth lips and periodontium. The study of dental trauma is called dental traumatology.- Types :* Tooth fractures**Enamel infraction**Enamel fracture**Enamel-dentine fracture...
each year. The incidence of dental avulsion in school aged children ranges from 0.5 to 16% of all dental trauma. Many of these teeth are knocked-out during school activities
Extracurricular activity
Extracurricular activities are activities performed by students that fall outside the realm of the normal curriculum of school or university education...
or sport
Sport
A Sport is all forms of physical activity which, through casual or organised participation, aim to use, maintain or improve physical fitness and provide entertainment to participants. Sport may be competitive, where a winner or winners can be identified by objective means, and may require a degree...
ing events such as contact sport
Contact sport
Many sports involve a degree of player-to-player or player-to-object contact. The term "contact sport" is used in both team sports and combat sports, medical terminology and television game shows, such as the Gladiators and Wipeout, to certain degrees...
s, football
Football
Football may refer to one of a number of team sports which all involve, to varying degrees, kicking a ball with the foot to score a goal. The most popular of these sports worldwide is association football, more commonly known as just "football" or "soccer"...
, basketball
Basketball
Basketball is a team sport in which two teams of five players try to score points by throwing or "shooting" a ball through the top of a basketball hoop while following a set of rules...
, and hockey
Hockey
Hockey is a family of sports in which two teams play against each other by trying to maneuver a ball or a puck into the opponent's goal using a hockey stick.-Etymology:...
.
Prevention
The best method for the prevention of knocked-out teeth is the use of helmets and mouth protectors. Mouth protectors can be very inexpensive, however, the compliance rate for their use is poor. Studies have shown that, even when mandated, athletes and other high risk individuals often will not use them. Also, even with their use, mouth guards can be knocked-out, leaving the user unprotected.Treatment and management
Although some dentistDentist
A dentist, also known as a 'dental surgeon', is a doctor that specializes in the diagnosis, prevention, and treatment of diseases and conditions of the oral cavity. The dentist's supporting team aides in providing oral health services...
s advise that the best treatment for an avulsed tooth is immediate replantation, for a variety of reasons this can be difficult for the non-professional person. The teeth are often covered with debris. This debris must be washed off with a physiological solution and not scrubbed. Often multiple teeth are knocked-out and the person will not know which socket an individual tooth belongs to. The injured victim may have other more serious injuries that require more immediate attention or injuries such as a severely lacerated bleeding lip
Lip
Lips are a visible body part at the mouth of humans and many animals. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech...
or gum that prevent easy visualization of the socket. Pain may be severe and the person may resist replantation of the teeth. People may, in light of infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
s (e.g. AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
), fear handling the teeth or touching the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
associated with them. If immediate replantation is not possible, the teeth should be placed in an appropriate storage solution and brought to a dentist who can then replant them. The dentist will clean the socket, wash the teeth if necessary, and replant them into their sockets. He will splint them to non-knocked-out teeth for a maximum of two weeks for teeth with normal alveolar process and bone support. Properly handled, even replantation of periodontally compromised permanent teeth in older patients under good maintenance have been reported, with splinting extending for over 4 weeks due to the reduced support structure for the root due to periodontal disease
Periodontal disease
Periodontitis is a set of inflammatory diseases affecting the periodontium, i.e., the tissues that surround and support the teeth. Periodontitis involves progressive loss of the alveolar bone around the teeth, and if left untreated, can lead to the loosening and subsequent loss of teeth...
. One week to ten days after the replantation, the dental pulps of the replanted teeth should be removed and a root canal
Root canal
A root canal is the space within the root of a tooth. It is part of a naturally occurring space within a tooth that consists of the pulp chamber , the main canal, and more intricate anatomical branches that may connect the root canals to each other or to the surface of the root.-Root canal anatomy:...
treatment completed within two months.
In addition, as recommended in all dental trauma
Dental trauma
Dental trauma refers to trauma to the face, mouth, and especially the teeth lips and periodontium. The study of dental trauma is called dental traumatology.- Types :* Tooth fractures**Enamel infraction**Enamel fracture**Enamel-dentine fracture...
s good oral hygiene
Oral hygiene
Teeth cleaning is part of oral hygiene and involves the removal of dental plaque from teeth with the intention of preventing cavities , gingivitis, and periodontal disease. People routinely clean their own teeth by brushing and interdental cleaning, and dental hygienists can remove hardened...
with 0.12% chlorhexidine gluconate
Chlorhexidine gluconate
Chlorhexidine is a chemical antiseptic. It is effective on both Gram-positive and Gram-negative bacteria, although it is less effective with some Gram-negative bacteria. It has both bactericidal and bacteriostatic mechanisms of action, the mechanism of action being membrane disruption, not ATPase...
mouthwash
Mouthwash
Mouthwash or mouth rinse is a product used to enhance oral hygiene. Some manufacturers of mouthwash claim that antiseptic and anti-plaque mouth rinse kill the bacterial plaque causing cavities, gingivitis, and bad breath. Anti-cavity mouth rinse uses fluoride to protect against tooth decay...
, a soft and cold diet, and avoidance of smoking
Smoking
Smoking is a practice in which a substance, most commonly tobacco or cannabis, is burned and the smoke is tasted or inhaled. This is primarily practised as a route of administration for recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them...
for several days may provide a favorable condition for periodontal ligaments regeneration.
Biologic basis for success of replanted knocked-out teeth
Every tooth is connected to its surrounding bone by the periodontal ligament. The tooth receives its nourishment through this ligament. When a tooth is knocked-out, this ligament is stretched and splits in half; half stays on the tooth root and half stays on the socket wall. If these two halves can be kept alive, the tooth can be replanted and the halves of the ligament will reattach and the tooth will remain vital. The half that stays on the socket wall, since it remains connected to the bone blood supply, is naturally kept alive. However, the ligament cells that remain on the tooth root lose their blood and nutrition supply and must be artificially maintained. They must be protected from two potentially destructive processes: cell crushing and loss of normal cell metabolism. All treatment between the time of the accident and the ultimate replantation must be focused on preventing these two possibilities.Prevention of cell crushing
When teeth are knocked-out, they end up on an artificial surface: the floor, the ground or material such as carpeting. If the surface is hard, the tooth root cells will be traumatized. Since the cells remaining on the tooth root are very delicate, additional trauma to the tooth root cells must be avoided so as to avoid more tooth root cell crushing. This damage can occur while picking the tooth up and/or during transportation to the dentist.When a tooth is picked up, it should always be grasped by the enamel on the crown. Finger pressure on the tooth root cells will cause cell crushing. Any attempt to clean off any debris should be avoided. Debris should always be washed off gently with, at the very least, a physiologic saline. Even with the use of a physiologic saline, the “scrubbing” of the tooth root to removed debris must be avoided. When placed in a physiologic solution, the tooth should be gently agitated to permit the cleansing of the tooth root. 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. For the same reasons, the method in which the knocked-out teeth are transported must be carefully selected. Placing the knocked-out teeth in transporting vehicles such as tissues and handkerchiefs can be damaging and transporting them in glass or cardboard containers can also be potentially damaging to the cells. 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. If the glass container does not have a tightly fitting top, then during the transportation, the physiologic storage solution can spill out and the teeth can fall, once again, on the floor and, at the same time, be out of a physiologic environment.
Maintenance of normal cell metabolism
Normally metabolizing tooth root cells have an internal cell pressure (osmolality) of 280-300 mOs and a pH of 7.2. When there is an uninterrupted blood supply, all of the metabolites (calcium, phosphate, potassium) and glucose that the cells require are provided. When the tooth is knocked-out, this normal blood supply is cut off and within 15 minutes most of the stored metabolites have been depleted and the cells will begin to die. Within one to two hours, enough cells will die that rejection of the tooth by the body at a later time is the usual outcome. The method by which the body rejects the replanted tooth is a process called “replacement root resorption”. During this process, the tooth root cells become necrotic (dead) and will activate the immunologic mechanism of the body to attempt to remove this necrotic layer and literally eats away the tooth root. This is called “root resorption” It is a slow, but non-painful, process that is sometimes not observed by x-rayX-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
s for years. Once this process starts, it is irreversible and the tooth will eventually fall out. In growing children, this can cause bone development problems because the replacement resorption (also termed ankylosis) attaches the tooth firmly to the jaw bone and stops normal tooth eruption and impedes normal jaw growth.
Research has shown that the critical factor for reduction of the death of the tooth root cells and the subsequent root replacement resorption following reimplantation of knocked-out teeth is maintenance of normal cell physiology
Cell physiology
Cell physiology is the biological study of the cell's mechanism and interaction in its environment. The term "physiology" refers to all the normal functions that take place in a living organism. Absorption of water by roots, production of food in the leaves, and growth of shoots towards light are...
and metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
of the cells left on the tooth root while the tooth is out of the socket. In order to maintain this normalcy, the environment in which the teeth are stored must supply the optimum internal cell pressure, cell nutrients and pH.
Storage media
There are many storage media available for knocked-out tooth storage. The most often recommended are: waterWater
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
, saliva
Saliva
Saliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...
, physiologic saline, milk, pH balanced cell preserving fluids, or under an armpit if no milk is available. Water and ice have been shown to damage the tooth root cells. The osmolality and pH of water and ice is very low (7-17mOs) compared to normal cell pressure (280 mOs). When a knocked-out tooth is placed in water, the cells attempt to equalize with the surrounding environment, the cell fluid tries to move to the outside pressure environment and burst. Water with table salt
Edible salt
Salt, also known as table salt, or rock salt, is a mineral that is composed primarily of sodium chloride , a chemical compound belonging to the larger class of ionic salts. It is essential for animal life in small quantities, but is harmful to animals and plants in excess...
in it is damaging to the knocked out teeth.
Saliva, that is placing the tooth under the accident victim’s tongue or in the cheek, has been recommended. Saliva, as a storage media, causes twice damage as water. Its osmolality is very low, causing bursting of the tooth root cells, but additionally, because saliva is filled with its normal flora
Bacteria in the human body
The human microbiome is the assemblage of microorganisms that reside on the surface and in deep layers of skin, in the saliva and oral mucosa, in the conjunctiva, and in the gastrointestinal tracts. They include bacteria, fungi, and archaea. Some of these organisms perform tasks that are useful...
of microorganisms, it will severely infect the tooth root cells. When the tooth is replanted, not only will the cells be necrotic but they will also infect the bone socket.
Physiologic saline has a fairly compatible osmolality and will not cause cell structure
Cell structure
Cell structure may refer to:* An organelle, or the layout of organelles of the biological cell itself* The structure of a covert cell, often involved in underground resistance, organised crime, terrorism or any group requiring stealth in its operations...
swelling but it lacks the metabolites and glucose necessary for maintenance of normal cell metabolism.
Milk has been also recommended as a storage medium for avulsed teeth. Its advantage is the high availability of cold fresh milk.
It was discovered 30 years ago to be less damaging to knocked out teeth than water or saliva. It was recommended because it has a compatible osmolality to tooth root cells and it is thought to be readily available. However, like physiologic saline, it lacks the necessary metabolites and glucose necessary to maintain normal cell metabolism of the tooth root cells. The cells on knocked-out tooth roots in milk do not die immediately but are unable to replicate (mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...
) and so are less able to reform new cells when replanted.
The most optimum storage media that are available have been shown to be pH balanced cell preserving solutions. The best known and most extensively tested is called Hank’s Balanced Salt Solution (HBSS). It has all of the metabolites such as Ca, P04, K+ and glucose that are necessary to maintain normal cell metabolism for long periods of time. HBSS has been extensively tested in dental and medical research for the past twenty years. This research has shown that 90% of cells stored in HBSS for 24 hours maintain their normal viability and after four days, still have 70%viable. In research studies, extracted dog’s teeth that have been placed in HBSS for four days can still be replanted with little signs of resorption. Hank's Balanced Salt Solution is found in a Save-A-Tooth.
HBSS also has been shown to be capable of replacing lost cell metabolites. Since a cell that has been cut-off from its blood supply depletes its stored metabolites after fifteen minutes, a tooth that has been extra-oral for one hour has less vital cells to reconnect with the bone ligament cells.
Some studies in dental research have shown that knocked out teeth that have been dry for up to one hour will have less resorption if they are soaked in a HBSS for 30 minutes prior to replantation. In these studies, dog’s teeth were extracted and left dry for 30, 45 and 60 minutes and then soaked in HBSS for 30 minutes and then reimplanted. These teeth showed 50% less replacement resorption following reimplantation. It has also been shown that keeping the teeth cold while in the HBSS does not affect success.
Many other types of storage liquids have been tested such as powdered milk
Powdered milk
Powdered milk is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and does not need to be refrigerated, due to its low moisture content. Another purpose is to reduce its bulk for...
, Enfamil, Gatorade, and contact lens solution. All of them have been shown to either be ineffective or damaging to avulsed tooth.
Complications and prognosis
The long-term prognosis of replanted knocked out teeth is very variable. The treatment for knocked-out teeth has progressed from a success rate of 10% to over 90%.However, this success rate can only be achieved with the institution of optimum care within fifteen minutes to an hour of the accident. In the case of knocked-out teeth, being prepared and knowing what to do can mean the difference between a person retaining or losing replanted knocked-out teeth for life. Teeth that have been knocked out when they are fully matured, that is, when the root has completely formed, have a much better prognosis than those teeth that are immature and not fully formed. This is due to the fragility of the root. When teeth have not fully formed, the walls of the root are thinner and thus more fragile. Another complication for the prognosis is the length of time that the tooth has been out of its socket. Teeth that are replanted within fifteen minutes of the accident have an excellent prognosis. Teeth that have been extra-oral and dry stored for more than one hour have a poor prognosis. Teeth that have been placed in an optimal storage medium within one hour of the accident also have an excellent prognosis. All teeth that have been knocked out should be replanted but watched carefully for the development of root resorption. Teeth that do not have root canal treatment within two weeks of replantation also have a poor prognosis.
History
The first reported cases of knocked-out teeth being replanted was by Pare’ in 1593. In 1706, Pierre FauchardPierre Fauchard
Pierre Fauchard was a significant French physician, credited as being the "father of modern dentistry". He is widely known for his book, Le chirurgien dentiste, "The Surgeon Dentist" 1728, where he described the basic oral anatomy and function, signs and symptoms of oral pathology, operative...
also reported replanting knocked out teeth. Wigoper in 1933 used a cast gold splint to hold reimplanted teeth in place. In 1959, Lenstrup and Skieller declared that the success rate of replanted knocked out teeth should be considered a temporary procedure because the success rate of less than 10% was so poor. In 1966 in a retrospective study, Andresen theorized that 90% of avulsed teeth could be successfully retained if they were replanted within the first 30 minutes of the accident. In 1974, Cvek showed that removal of the dental pulp
Pulp (tooth)
The dental pulp is the part in the center of a tooth made up of living connective tissue and cells called odontoblasts.- Anatomy :Each person can have a total of up to 52 pulp organs, 32 in the permanent and 20 in the primary teeth....
following reimplantation was necessary to prevent resorption of the tooth root. In 1974, Cvek showed that storage of knocked out teeth in saline could improve the success of replanted teeth. In 1977, Lindskog et al. showed that the key to retention of the knocked-out teeth was to maintain the vitality of the periodontal ligament. In 1980, Blomlof showed the storing the periodontal ligament cells in a biocompatible medium could extend the extra oral time to four hours or more. He found that the best storage medium was a medical research fluid called Hank’s Balanced Solution. In this study, it was serendipitously discovered that milk could also maintain cell viability for two hours. In 1981, Andreasen showed that crushing of cells on the tooth root could cause death of the cells and lead to resorption and reduction in prognosis. In 1983, Matsson et al. showed that soaking in Hank’s Balanced Solution for thirty minutes prior to reimplantation could revitalize extracted dog’s teeth that were dry for 60 minutes. In 1989, a systematic storage device was developed to optimally store and preserve knocked out teeth. In 1992, Trope et al. showed that extracted dog’s teeth could be stored in Hank’s Balanced Solution for up to 96 hours and still maintain significant vitality. In this study, milk was only able to maintain vitality for two hours.