A source of evidence based treatment guidelines for dental trauma
International Association of Dental Traumatology (IADT)
American Association of Endodontists Foundation (AAE)
European Academy of Paediatric Dentistry (EAPD)
Swedish Pedodontic Society
Greek Association for Orthodontic Study and Research
Danish Dental Association (DTF)
University Hospital of Copenhagen
Colgate / Palmolive
National Regional Fund for Projects in Dentistry (Bestyrelsen for Midler til fælles
Foranstaltninger på Tandlægeområdet og Dansk Tandlæge Forening)
Dental traumatology, the evidence problem
Dental trauma cases often result in a treatment sequence that involves both general dentists and many specialists. Optimal treatment relies upon the expertise of a broad spectrum of dental specialists such as oral and maxillofacial surgeons, pediatric dentists, endodontists, orthodontists, prosthodontists and periodontists. The primary urgent care is frequently provided by the oral and maxillofacial surgeon or the pediatric dentist in a hospital emergency department setting. Subsequently the patient may be referred to a general dentist or an endodontist for secondary level care such as endodontic and restorative management. Later the orthodontist and prosthodontists and periodontist may become involved with additional treatment. The long chain of referrals that are frequently seen in dental trauma cases means that control of the overall quality of treatment is often lost. While the specialists involved are usually eager to take credit for their successes, they are often very reluctant to take responsibility for the treatment failures. The research activity in clinical traumatology has been extremely low and in some sense dental traumatology has become an orphan in dentistry (1).
At the end of the last century there was a growing interest among all dental disciplines in analyzing the validity of existing treatment principles which lead to the recognition that evidence based dentistry (EBD) with the randomized clinical trial (RCT) as the
gold standard was the path for the future (2 - 4). In the famous pyramid “Mount evidence” most studies in dental traumatology belong at very low levels in the evidence pyramid. Only a couple of clinical RCTs have yet been published, and the prospect for future RCTs appears slim (5).
What is the cause of this problem?
First of all, the shared responsibility among several dental specialities makes research in dental traumatology complicated to organize and evaluate. Secondly, the ethical problems associated with getting informed consent from an injured child or adult to participate in an RCT are unavoidable. Resonable arguments for carrying out the experiments in spite of these problems are rarely present. This obstacle is almost prohibitive for most RCTs dealing with treatment of acute traumatic dental injuries.
What are the alternatives?
Often animal models are the best alternative. They allow the researchers to control the parameters that may influence the outcome of the experiment in a fashion not attainable in human studies as the injuries can be inflicted by the examiner under controlled conditions (6). The current treatment guidelines give testimony to the value of animal
experiments as they rely heavily on information obtained from animal studies (7).
Are animal experiments reliable?
This question has been examined carefully and monkey experiments seem to have a high degree of reliability (7), whereas the use of dogs often seem to give too optimistic results in relation to pulp healing (6). Rat studies appear to show a significant variance in periodontal ligament (PDL) healing with a likelihood of transient ankylosis, which makes this model unreliable in dental trauma studies affecting the PDL (8).
Are human clinical non-randomised studies a valid approach to assess the effect of dental trauma treatments?
If the correct statistical models are used, and groups with similar preinjury and injury characteristics can be isolated and compared, then it is possible to reduce the amount of interference caused by confounding factors. The results must however be evaluated with a certain amount of reservation as the risk of interference by confounding factors can never be eliminated with certainty. This type of analysis has so far offered useful information about the effect of various treatment procedures such as repositioning, type and length of splinting times (9, 10) and the use of antibiotics (11).
How big is the knowledge gap before we can have the necessary scientific foundation for offering evidence based treatment for all dental trauma types?
To answer that question one must start by focusing on the strongest predictor for successful/unsuccessful trauma healing, namely the trauma type. Dental trauma can be divided into 9 fracture and 6 luxation entities. Combination injuries in which both luxation and fracture have occurred are unfortunately frequent, causing 54 combinations which must be seen as 54 distinct healing scenarios (12). The complexity is further increased by the fact that trauma to the primary and the permanent teeth
must be treated as separate entities. This results in 108 distinct trauma
events! One single word may characterize treatment of traumatic dental injuries around the world: CHAOS.
Several predictores for pulp and periodontal healing have been identified for the individual trauma entities
(13). Some reflect the severity and nature of the trauma inflicted, some describe patient characteristics, and some reflect the influence of the choice of treatment. The strongest predictor appears to be the trauma type. The stage of root development appears to be a strong outcomes predictor for all types of dental trauma, and it affects both pulpal and periodontal healing. This is not surprising since a good blood supply is esential for pulpal healing and thus the size of the apical foramen is directly related to the revascularization potential of the affected tooth (14).
The choice of treatment offered has a direct effect on the healing outcome for luxation injuries where several treatment options frequently are available such as ± repositioning, ± splinting and ± antibiotics (14).
For treatment of crown fractures with exposed dentin and/or the pulp (15) the amount of research needed before reliable answers to all treatment possibilities have been covered seems formidable. For crown-root fractures there are several treatment options
and extensive research is needed before reliable answers can be established as to which treatment option offers the best possible treatment (16).
The multitude of possible trauma scenarios and the broad variaty of treatment options make it very difficult for practitioners to provide evidence based treatment and recommend the best possible treatment choice for the patient. Keeping this in mind, it is not surprising that much dental trauma treatment worldwide is far from ideal. Surveys in England, Australia, New Zealand, Tanzania, Brazil, Switzerland have shown that knowledge of adequate treatment of traumatised teeth is deficient, implying that up to half of all treatments offered are either not necessary or directly harmful to the patient (17 - 29).
The Dental Trauma Guide is an attempt to elevate this unfortunate situation by making the current knowledge in dental traumatology easily available on the internet. For 40 years, patient records have been collected at the University Hospital in Copenhagen, creating the information contained in the extensive database used in developing the Dental Trauma Guide for
treatment selection and prognosis estimation. Since 1965 standardized documentation of
long term effects of trauma treatments has been collected and this material (4000 cases) together with the results of
80 clinical studies and 65 experimental animal studies using monkeys now forms the scientific basis for the Dental Trauma Guide (7).
An effort has been made to make the information available in a structured and userfriendly fashion allowing the practitioner to develop a correct diagnosis, a treatment plan, and a follow-up plan along with identifying a risk estimate for healing complications.
Arriving at the correct diagnosis
As previously mentioned, a traumatized tooth may suffer one of 108 distinct trauma conditions. The correct choice of treatement is obviously dependent on the ability of the practitioner to make the correct diagnosis. In this respect the Dental Trauma Guide will follow the international WHO classification (30). To help the newcomers in dental traumatology a Trauma Pathfinder will be incorporated in the website to guide the practitioner via a series of ‘yes’ and ‘no’ questions to a correct diagnosis.
At a later stage (Version 2.0) an interactive Electronic Patient Record will be included in the guide. It will be possible to use the Electronic Patient Record as a quality measure as this record will remind the practitioner to perform and answer all pertinent questions for the trauma entity being recorded.
Selecting treatments which may optimize pulp and periodontal healing
A paradox in dental traumatology is that almost all treatment procedures impose an element of new trauma when applied, i.e. being traumatogenic (5, 31). To mention a few, repositioning of a displaced tooth manually or by forceps will damage or destroy thousands or millions of PDL cells. Application of many types of splints, especially arch bars, in which loosened teeth are fastened to an arch bar with wires will create large compression zones in the PDL due to tightening of the steel wires and establish invasion paths for bacteria along subgingivally placed wires. Insufficient coverage of exposed dentin and pulp may lead to microleakage with formation of anaerobic bacterial colonies, which may seriously damage the pulp. Proper treatment selection, which sometimes means minimal or no treatment, is therefore crucial.
In the Dental Trauma Guide treatment approaches is presented for which treatment effects have been documented experimentally in animal models and at least to some extent in clinical studies. In case of treatment alternatives, the pros and cons for each treatment is outlined.
Follow-up regimens for dental trauma patients
An optimal follow-up plan should aim at selecting points in time where the chances of diagnosing healing complications are most effective. For obvious reasons cost and the convenience of the patient and practitioner have to be taken in to consideration when constructiong a good and cost-effective control system. The suggested follow-up plan for a given trauma entity are proposed based on a series of clinical studies where survival analysis has documented the most optimal time for diagnosis of pulp and periodontal healing complications (32).
Description and diagnosis of healing complications.
In the Dental Trauma Guide the terminology of healing complications has been based on the 2007 edition of the Textbook and Color Atlas of Traumatic Dental Injuries by Andreasen et al. (31). In relation to pulpal healing the following outcome descriptions are used:
- Pulp necrosis (sterile or infected)
- Pulp canal obliteration (partial or total)
- Pulp metaplasia including internal PDL and/or bone formation.
In relation to PDL healing the following healing complications are described:
- Repair-related root surface resorption
- Infection-related root surface (inflammatory) resorption
- Progressive or transient osseous root surface ankylosis-related (replacement) resorption
Root resorption may also occur in the root canal whereby the following entities appear:
- Repair-related root canal resorption
- Infection-related root canal resorption
- Osseous ankylosis-related (replacement) root canal resorption.
Concerning the marginal periodontium the following two entities are recognized:
- Permanent marginal bone loss
- Transient marginal bone loss
In regard to root development disturbances, traumas often affects teeth with incomplete root formation at time of injury and the healing complications are often partial or total arrest of root development.
Finally and probably the most essential complication is tooth loss usually caused by the abovementioned healing complications.
Prediction of healing complications
Several clinical studies have been done to identify healing/non healing predictors for the various trauma entities. These studies have so far identified 15 predictors, which have been significantly linked to the occurrence of healing complications (13). Some of these factors have been shown to be very strong (type and extent of injury and stage of root development) whereas others only have a minor influence (treatment). The identification of these factors is usually based on a multivariate statistical analysis with regression analysis being the primary tool (33). To some extent the influence these predictors has on pulp and periodontal healing can be verified by the result found from the monkey experiments (6).
One of the goals for the Dental Trauma Guide is to give the dental practitioner a tool whereby a risk profile can be developed for an individual patient with a given trauma entity. This naturally raises the question about how reliable these predictors are and how many predictors should be used in each case to make a safe prediction. This problem has to a certain extent been examined by comparing the results gained by using different statistical models (lifetable analysis, cox regression, logistic regression
and decision tree analysis).
Widely used measures for evaluating the usefullness of a predictive model are sensitivity and specificity. The sensitivity of the model is a measure of how good it is at identifying patients who will develop healing complications, and the specificity is a measure of how good the model is at identifying patients that will remain free of healing complications (33).
The ideal combination is of course a model with both a high sensitivity and high specificity; this however, is often not possible to achieve. The best model representation is often chosen based on the tradeoff between these two quality parameters (33, 34). We are
presently evaluating the results of several statistical models in order to choose the best possible predictive model. Currently we have made prognosis estimation available in the form of lifetable analysis of a subselection of patients with similar healing predictors.
In practice the user will select a group of patients from the database with a similar set of predictors (e.g. stage of root development,
luxation and fracture type) as the actual patient. The program will then isolate a number of patients in the database with the specified patient and injury characteristics. For this group of patients the program will then conduct a lifetable analysis covering 5-20 years for pulpal and PDL healing complications as well as for tooth survival. The strength of this approach is that only the information contained in the sub-selection of patients will be used for prognosis estimation. The weakness is that a very extensive library of injuries cases has to be present in order for the sub-selections to contain enough patients for accurate prognosis estimation. An advantage of this approach is that no assumptions about the mutual relationship between parameters have to be considered.
Presently the trauma archives at the University Hospital contains 40.000 patient trauma records, all having standardized clinical, radiographic and photographic documentation of the type and extent of the injury including associated soft tissue injuries as well as information about the treatment offered. Approximately 10 %, or 4000 patients, have had long-term follow-up of 1 year or more and these patients constitute the core of the trauma database (7). These traumas are to a large extent representative for the 104 different trauma scenarios (see earlier).
What is the status of Dental Trauma Guide?
In 2005 it was decided to combine all the existing trauma databases covering various dental trauma entities at the University Hospital in Copenhagen to one unit. This
involved harmonizing 18 individual trauma studies. In 2008 the data from these 18 studies had been harmonized and were ready for an overall predictor analysis; this project is about to be completed now.
The first version of the Dental Trauma Guide (version 1.0) includes all injuries affecting the permanent dentition and is now available on the internet and is currently being tested
for its reliability by four trauma centers. The next step in the development of the Dental Trauma Guide will be to incorporate information about primary tooth injuries and their subsequent sequelae to permanent successors; this work is planned to be ready for release early 2010 (Version 2.0).
Economic background behind the Dental Trauma Guide
The project has only been possible thanks to a number of national and international sponsors. In this regard the Copenhagen University Hospital, the Copenhagen Dental School, the Danish National Dental Association and various
national research funds (Velux Foundation, Augustinus Foundation and Spies Research Foundation) have been instrumental in the initial phase of the project. International important supporters, such as the American Association of Endodontists (AAE) , the International Association of Dental Traumatology(IADT), the European Association of Paediatric Dentistry (EAPD), the Swedish Paediatric Society and the Greek Orthodontic Society have all made significant contributions to fund the construction of Version 1.0.
In the future, further grant support is needed to complete Version 2.0. Even after version 2.0 have been complete there will be a continued need for grant support in order to keep the Dental Trauma Guide "alive", i.e. to make corrections and to incorporate new materials and new treatments when they become available. To accomplish this, it is planned to have certain features of the Dental Trauma Guide linked to a "payment for service scheme." Paying members will have access to the digital patient record,
the print-out facility of contents from the patient data and follow-up schedule and individualized prognosis estimation. Another possible member’s benefit is direct download of scientific articles in PDF format or as abstracts when copyright prohibits direct download.
Negotiations with several dental specialty organisations are under way in regard to a subscription option in which the organisations for a fee per member will be able to grant all their members free access to the advanced features of the Dental Trauma Guide. It is the hope that such an arrangement will be able to keep the Dental Trauma Guide alive and growing in the years to come.
Staff behind the Dental Trauma Guide
The principal investigator is Dr. Jens Ove Andreasen and the chief programmer and developer Søren Steno Ahrensburg. These two are supported by a series of other investigators such of Dr. Eva Lauridsen and Dr. Nuno Hermann, both attached to the Department of Pediatric Dentistry and Clinical Genetics, Copenhagen Dental School. Furthermore the following staff oral and maxillofacial surgeons, Dr. Morten Schiødt, Dr. Jette Daugaard-Jensen, Dr. Søren Hillerup, Dr. Thomas Kofod, Dr. Ole Schwartz, Dr. Simon Storgaard Jensen and research associate Dr. Frances Meriam Andreasen are participating. The following statisticians from the BioStatistical Department of Copenhagen University have been advisors and are currently working on statistical modeling for the statistical part of the Dental Trauma Guide, Thomas Gerds, Per Kragh Andersen and Lone Mogensen.
Aims for the future of the Dental Trauma Guide
It is the aspiration of the designers of the Dental Trauma Guide that it may raise the standard of care of dental trauma patients worldwide. The dental trauma problem is certainly a global phenomenon. The frequency of dental traumas in a population is very high and involvement is estimated to be a round 50-60% (including both the primary and the permanent dentition) (35). It is likely that the world today has more than 3 billion trauma victims and to this figure is added 60 million new patients each year!
In 1989 a study was conducted in Denmark and Sweden where the cost of the first "definitive" treatment of dental traumas was calculated and it amounted to US$5,000,000 / per million inhabitants, a figure which has doubled since then (35). This is certainly imposing a serious financial burden on all trauma patients and to some extent also on society. If the guide can optimize the initial treatment, which is so crucial for the final outcome, this may lessen the multiplicity of problems facing of all trauma victims.
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