|ROOTS Summit V – Monterrey Mexico 2005 (transcription by Rob Kaufmann)
Clinical management of the Avulsed Tooth - Dr. Martin Trope
Clinical management of the avulsed tooth is the prevention or treatment of root resorption. When a tooth undergoes a traumatic injury that results in luxation or movement of the tooth in the socket, the long term success or failure will be assessed based on the presence or absence of root resorption.
In order to understand the clinical management of these cases, we must understand the mechanisms and pathogenesis of root resorption. Primary and permanent teeth are different. Primary teeth are “preprogrammed’ to resorb. Permanent teeth on the other hand are programmed to resist resorption. When we have AP due to necrotic tissue products, we get bone resorption rather than root resorption. The reason for this is the cemental outer layer. That’s why we get Periradicular periodontitis only associated with POEs because that is the origin of the inflammatory stimuli. As long as there is cementum present, these inflammatory stimulators will not communicate with the PDL you will not have disease. The precementum/cemental layer is the area that is resistant to resorption. (In the inner surface of the tooth the preodontoblastic/odontoblastic layer that is resistant. This is why we often see a “shadow” of the pre-existing canal space in cases of external resorption.) If these layers are removed, we will not only have bone resorption and pulpal inflammation, we will have root resorption as well. The best way to do this is by luxation injury.
Tooth avulsion is a surprisingly small injury from a cemental point of view. Most of the damage is tearing of the PDL. There are only going to be a few areas of scraping, crushing and compression of the cells. There is the potential for inflammation. You will also always have cutting of the neurovascular bundle that will result in necrotic pulp. BUT the necrosis of pulp in itself is not the problem – it is its susceptibility to infection that causes disease. This occurs in about 3-4 weeks. If we treat the tooth properly from the start we can limit the problem to necrosis and avoid the effects of infection.
Protective Layer Damage – (Highest to lowest in severity)
Intrusion – a VERY damaging injury, massive crushing of the PDL – poorest prognosis. Intrusions are almost always result in pulpal necrosis
Avulsion – we only have very small areas of damage. Where the PDL is torn there IS the potential for complete healing. But we have a very small window of opportunity. If the tooth is not treated properly, the PDL cells then become strong inflammatory stimuli and this causes root damage with resultant “unfavorable healing”. Avulsions always result in pulpal necrosis.
As we move down the list, the likelihood of pulpal necrosis lessens. If it doesn’t become necrotic, the potential for infection is zero. If it does, the potential is always there.
The consequence of avulsion in the compressed (fulcrum) areas of the attachment apparatus is always the same- inflammation. If the cementum is penetrated and the dentin is exposed to the inflammatory cells – the dentin will stimulate the formation of multinucleated clastic cells and resorption will result. If the inflammation is NOT progressive stimulus (just from the injury itself) then the inflammation will burn itself out and resolve. Once the dead and dying and damaged cells are dealt with, the inflammation goes into the healing phase. At that stage, healing becomes a competition between the cells in the area. If the damage to the root is small, cementoblasts and PDL cells have the ability to cover the root with new cementum and new PDL and the response is considered “favorable healing”. If the area is diffuse and the damaged area of the root is large, once the initial inflammatory response is over, the race between the cells will favor the osteoclasts/blasts - bone producing cells. These attach to the root, prevent formation of cementum, and produce a resorption/apposition phase. These cells do not differentiate between tooth and bone. When we do get to the appositional phase – the osteoblasts only have the potential to form bone and NOT dentin. Then another area is resorbed and in that way, slowly the root is eventually replaced by bone. This technically is considered a “healing” response but it is “unfavorable healing”.
The active phase is destructive (bone resorption, root resorption) and it is lucent on a radiograph.
The healing phase is NEVER lucent and NOT destructive.
We have been taught that anything that is lucent on a film is bad and that it needs treatment. However, identifying those “transient” lucencies that are actually healing can be very diagnostically challenging. When a tooth is replanted, by definition there is always some inflammation, some associated resorption and resulting lucency. We have to be able to understand which one of these lucencies will result in spontaneous healing and which ones are a “progressive stimulus” that have the potential for unfavorable healing. This can be a tough decision. Trope showed a case where traumatized teeth initially had initial increase in PA radiolucency at 3 weeks post trauma that eventually had spontaneous healing shown radiographically at 6 weeks and 4 mos. However, if the teeth became necrotic and infected- the PA stimulus could be so severe that in 4-6 weeks the tooth could be lost.
So, we need to improve our diagnostic techniques. (The latest tool is Laser Doppler Flowmetry but it is currently too expensive to be in general use by dentists. It measures blood flow in the tooth.) Therefore we have to have good history. If this is a recent mild injury and you suspect the tooth might respond with favorable healing AND the patient will comply with weekly visits for 4-6 weeks, the prudent thing to do might be to watch and wait. However, if the injury is severe, is in a tooth with a closed apex, there is no reason to believe that the pulp is vital – we would NOT take the chance that the pulp will become infected and initiate endo treatment at the 7-10 day period.
Inflammation = Local (small) Damage -- we expect Cemental Healing (Favorable Healing) Occurs in first few weeks – small area of resorption is followed by new cementum and PDL.
Tooth Avulsion with Localized damage? If tooth is replanted IMMEDIATELY (and we deal with the problem of potential pupal infection) we would expect cemental healing because of minimal localized damage.
Inflammation = Diffuse Damage -- likely Osseous Replacement. Assuming there is no progressive stimulus from the pulp the first sign is ankylosis (bone against root without a PDL in between). Ankylosis per se, is not bad. Unfortunately, bone constantly undergoes remodeling (which is normal for bone). In this way, the root is slowly replaced by bone. It has a particular radiolucent appearance – it looks like bone and is not lucent. It is a healing response – albeit an unfavorable one. (Example/ a tooth replanted with excessive dry time) The products of PDL lysis cause a potent inflammatory stimulus once the tooth is replanted and the result is osseous replacement. There is nothing we can do in that case. The root will be replaced with bone.
Attachment Damage and Pulpal infection
The most damaging situation is where we have both cemental damage AND inflammatory stimulators in the root canal system. The pulp is always necrotic after an injury and our job as clinicians is to make sure that the canal system does not become infected. If you have a combination infection in the RCS combined with damaged cementum, the inflammatory stimulus can move THROUGH the dentin tubules and stimulate bone resorption all over the root – not just at the POEs. Not only will you get bone resorption in these areas but the root is no longer protected by cementum because of the injury – resulting in root resorption. Therefore you will get a combination of bone and root resorption - the worst possible result. This appears radiolucent on a radiograph and this destructive process will continue until we remove the stimulus – the infected pulp. While we do not have control over healing of the traumatized protective layer damage (PDL/ cementum) but we must limit additional damage caused by the infected root canal system. That is the one area where we DO have control. One interesting thing to note is that even in extensively externally resorbed cases, the root canal space is intact due to the protective effect of the odontoblast/preodontoblast layer. (Even if the pulp is necrotic!) Similarly – INTERNAL resorptive lesions rarely perforate the external root surface due to the protective effect of the cemental layer!)
With this in mind, we need to be practical. When we consider treatment objectives for the Avulsed tooth we must understand that there are certain things over which we have NO control and things that we CAN control.
Treatment objectives should focus on:
Limit the Attachment Damage Inflammation
The Attachment Damage has usually already occurred when the patient sustains the injury. However we have the ability to limit or influence the Inflammation that occurs as a result of the injury. Inflammation is the enemy in the initial visit. Emergency treatment should be aimed at minimizing or shutting down inflammation.
Treat the Pulp Space Infection – the pulp is necrotic. So we need to do all we can to prevent or treat pulpal infection. The second visit is focused on treating the potential pulpal infection.
Management of the Emergency Trauma Patient
Treatment focus: Minimize inflammation due to attachment damage. The “dry time” is our biggest enemy. If we examine PDL cell death vs. extraoral dry time, the critical time seems to at the 30 min stage (and particularly at the 45 or 60 minute stage) the cells die very quickly. If you look at success or failure, the 30-45-60 minute dry time seems to correlate well with success rates. We need to minimize the dry time.
The absolute best treatment is to replant the tooth back in the socket IMMEDIATELY (or in appropriate storage medium). Unfortunately, we have been doing a very poor job or educating the public about this. 80% of avulsions are found to occur within 100 m of the school or home. Therefore, if our efforts can successfully be focused on educators, school nurse, coaches and parents – 80% of the problems will be solved.
The tooth should be rinsed gently with water or saline to remove any surface bacteria and accident debris. There is a 15-20% increase in success rates when the tooth is washed in this way before replantation. ( Weinstein et al 1981)
Outside the Dental Office - Storage Medium– You can use:
Saliva – Spitting into a cup, place under cheek or tongue
Milk – medium of choice in many cases ( osmotic pressure is close – you have 2-3 hours time)
Specialized Media – Hank’s balanced Salt Solution (HBSS-2 year shelf life) and others – can keep cells viable for a long time. The problem is to have the media available at the injury site.
Water is BAD – causes osmotic pressure and cells explode – not much better than dry.
If the patient has any loss of consciousness – possible neurological damage- send them to hospital.
Inside the Dental Office- The Emergency Visit
If the tooth was repositioned at the site of the accident - inspect and readjust if necessary
If it is in a medium (HBSS or Milk) we need to take a good history and inspection of the socket before we replant. We always need to check for a more serious injury. They need to remember everything. Make sure the patient HIMSELF must answer, remember what happened, and follow you. There should also be NO fluid loss from any orifice – bleeding from nose or ears is serious and patient should be hospitalized.
Find out EXACT dry time. Ask it in SEVERAL different ways so you know exactly how log tooth was dry. This will GREATLY influence how we treat the case.
Check socket with radiograph and visually after removing the blood clot. For example – in many children the socket may be crushed and closed. We may have to widen socket with blunt instrument and remove any sequestra if necessary.
Assess the maturity of the tooth. If the apex of the tooth has an apical diameter of MORE or LESS than 1 mm (size 100 instrument) we will treat them differently. Mature is < 1 mm apical size.
TX - MATURE TEETH - Dry time was < 60 minutes
At <60 min dry time, the PDL is worth keeping therefore we try to salvage it. If the tooth has been stored in media – replant in socket. If not - wash the tooth first and then replant.
TX - MATURE TEETH - Dry time was > 60 minutes
Do endo on tooth extraorally first – there is no rush to do this.
If the dry time was > 60 minutes -> the PDL is probably not viable and NOT worth keeping. We will need to remove the PDL before replantation because we don’t want the dead PDL to act as a severe inflammatory stimulus – We do this with the knowledge that osseous replacement is inevitable but we try to slow “unfavorable healing” as much as possible.
Acid etch (citric acid – 30 secs.) the root surface. 30 sec. - 1 min maximum because we only want to remove the dead PDL /soft tissue – we DON’T want to remove the cementum. The tooth then basically serves as a space maintainer until the young patient’s facial growth is complete. It can then be prosthetically replaced.
After removing the PDL – Soak tooth in Fluoride for 5 minutes. (This has been shown to extend osseous replacement time by 2 X)
Use of Emdogain- (enamel matrix protein) is supposed to slow down osseous replacement AND stimulate formation of new cementum/PDL. (Igbal & Bamas 2001) The efficacy of Emdogain has not been conclusively proven yet. Trope feels that asking Emdogain to repopulate an entire root surface is asking too much. It may be better in 30-60 min. situations where only small areas of the PDL have died. Trope says that if the patient is willing to absorb the cost – he suggests that it be used on all cases like this.
TX - IMMATURE TEETH - Dry time was < 60 minutes
In teeth with apices greater than 1 mm there is a potential for revascularization of the pulp space. That is a tremendous advantage if we can do it. The pulp is necrotic BUT if the apex is open and the root is short – we have potential for revascularization. Ideally we want further root development with thick root walls. In dogs, revascularization has been shown to occur consistently in 30 days.
Soak the tooth in Doxycycline (1 mg/20 ml) for 5 min prior to replant. Research in animal models shows a doubling of success rates of revascularization. Recent research with Minocycline topical (a powder that sticks to the root) shows further increase in success rates. Trope uses Minocycline in the sulcus of every luxated teeth because one of the pathways of infection is the clot in the socket. This material gives you 15 says of protection which is more than enough time for the PDL to close of the entrance way.
TX - IMMATURE TEETH - Dry time was > 60 minutes
Most clinicians would not replant a tooth like this. Trope feels that NOT attempting to treat these teeth is a mistake. He believes that if we can place a ROOT in the socket – we can maintain the thickness and height of the socket. At the first sign of intrusive ankylosis – we cut off the crown and SUBMERGE the root.
Splints should be flexible and self cleansing. Trope prefers the TTS (Swiss) splint. Splints should allow some movement of the tooth but he feels the self cleansing aspect is very important to prevent bacterial ingress in the crevice. To do this – extend the splint ONLY as far as minimally necessary for stability.
Method – Attach splint wire to adjacent teeth first (NOT to the avulsed tooth). A pink wax bite registration is prepared and with the patient anesthetized – they are asked to bite into the wax. This forces the avulsed tooth apically, seating it in the socket. The tooth is then attached to the arch wire.
What else can we do (once emergency treatment has been performed) as Adjunctive Therapy?
Systemic Tetracycline (NOT Penicillin) for 7-10 days. It has antibacterial AND antiresorptive properties.
Systemic Corticosteroids – have not been found to be useful.
Systemic NSAIDs – good for pain relief and effects on inflammatory response.
Chlorhexidine Rinses – keep sulcular bacteria in check and aid healing
Trope’s research on shutting down the inflammatory response
If the inflammatory response can be minimized, resorption can be decreased. Normally we would not do endo until 7-10 days after the emergency visit. Trope was interested to see if using the canal space as a reservoir for anti-inflammatory medication AT THE TIME OF FIRST EMERGENCY TX could make a difference.
Bryson UNC (Thesis) - Chemotherapeutic inhibition of root resorption in replanted dog teeth.
Method – 60 minute extracted dried teeth (expected poor healing) –
In one group - pulp was broached and Ledermix Paste 1% Triamcinolone (corticosteroid) and 3% Demeclocycline (Broad spectrum Ab) spun into canal with Lentulo
Second group - pulp was broached and CaOH spun into canal with Lentulo. (CaOH is antibacterial but NOT anti-inflammatory)
Results - 60 % of the root surface had favorable healing with Ledermix vs. 14 % with CaOH
Histologic evaluation of thickness of remaining root structure – 3-4 x better than CaOH or without active intracanal medicament.
In the previous research the tetracycline component of Ledermix caused the dog teeth to turn green. By separating the Ledermix components into Corticosteroid and Ab Trope found that by using ONLY the Triamcinolone (which is a VERY low dose corticosteroid) equally good results could be achieved without the risk of discoloration from the Tetracycline component. The next phase of research is to raise the level of corticosteroid and see if dramatic decrease in inflammation occurs. If this is the case then the whole theory of emergency treatment will change and initial emergency treatment will involve not waiting 7-10 days to do the endo – but placing corticosteroid in the canal ASAP after the trauma. (Hong et al 2005)
Open Apex - 2nd Visit – at 7-10 days
The goal of treatment at this time is to prevent or treat pulpal infection. The best way to prevent pulpal infection is to have a VITAL pulp. Revascularization is possible at the emergency visit. But we have a tremendous dilemma. If things go bad – the root can be lost in weeks. You need a very compliant patient who is willing to return WEEKLY for up to 6 weeks so you can judge the progress of the case.
Laser Doppler Flowmetry can help with evaluation. It measures a “pulse” inside the tooth. He showed a case of severe luxation of two central incisors. At 1 week there was no indication of pulse but at 3 months the pulse returned and vitality was restored. You can tell in as little as 4 weeks. Nee units will be available soon (~ $1K cost) and have the potential to replace the EPT.
Closed Apex - 2nd Visit – at 7-10 days
There is no hope for revascularization. Infection will take 3-4 weeks. It is critical that we do NSRCT within 3 weeks (7-10 days ideal). You could potentially do a one step endo. The splint is removed at 7-10 days and after the endo is finished. OR you could place CaOH with a Lentulo and then finish in 3-4 weeks.
Treating Pulp Space Infection
This is different problem and difficult problem. If you have signs of active root resorption AND pulp space infection that means that bacteria in the canal space can now penetrate the dentinal tubules and work there way through to the PDL since the protective cemental layer is no longer there. In that case we need LONG TERM CaOH. The purpose is to elevate the PH of the dentinal tubules by having the CaOH leach into the tubules. But this takes a long time. CaOH also neutralizes endotoxin.
Trope suggests CaOH without additional radio-opaquers. It is important that we can see the fill of CaOH because we need to re-evaluate in 3 mos. time whether we need to replace the CaOH. If after 3 months the canal is lucent – then you need to replace the CaOH. If it looks filled as it did when the CaOH was placed – leave it.
You evaluate healing by the appearance of the adjacent bone. Each tooth is different. You fill the tooth when the active destructive resorption changes to a healing phase and has been replaced by normal looking bone. This may take 3, 6 or even 18 months. If it is - you are ready to place the root canal filling.
Follow up schedule is 3 mo., 6 mo., 12 mo., and yearly for 5 years. You are going to evaluate for active root resorption. If it is present we need to find out the source of the progressive stimulus and take measures to reverse it. If there is replacement resorption, we need to create a treatment plan that minimizes the destructive effects and maximize the permanence of the final restoration. End