By Dr Larz S.W. Sphgberg, m s . Phn, Department of Endodontology, School of Dental Medicine, University of Connecticut, Farmington, USA.

Address for correspondence; Larz Sphgberg, liniversity of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030- 1 71 5. Email: Spangberg:@nsol .uchc.edu

To Do A “Root Canal” Abstract

Endodontic treatment is often referred to as “a root canal”. This article discusses the need to be more refined and descriptive in the selection of treatment alternatives. The pathological involvement of teeth needing endodontic treatment varies significantly from superficial pulp inflammation to pulp necrosis and infection, often complicated with a periradicular osteolytic process. This diversity should lead to a variety of treatment modalities based on the severity of the disease. Failure to do so and use a one-size-fits-all approach - “a root canal” - is an oversimplification and a disservice to the patient and the profession.

Introduction Evidence-based patient care is a generally accepted concept in

contemporary dental practice Although evidence-based pi actice is the explicit and judicious use of the current best evidence in conjunction with clinical experience, there is a great deal of dis- agreement regarding its practice

In endodontic practice there are conflicts daily when trying to practice according to evidence There is poor distinction between facts and fiction in clinical endodontics There are several facts available, however, which may serve as a foundation for some decision making Kakehashi et al ( I ) showed in rats that odontogenic periapical bone lesions developed as a result of root canal infection Later studies in both animals and humans have firmly established that periradicular bone osteolysis develops as a result of an infection of a necrotic pulp (2-5) This is an established fact

Collected evidence from clinical studies of high quality has set down a clear correlation between endodontic infection antl peri apical osteolytic disease processes (2-5) This is an established fact

A third well-established fact is that microorganisms can be retrieved from root canals of teeth where earlier endodontic treatment has failed The micro-flora in these root canals differ from that of root canals with initial pulp necrosis (2, 6-8)

Diagnosis Endodontic diagnosis is rather simple in most cases In the

overwhelming number of situations, in daily practice. the dentist deals with only five endodontic conditions First, an important step in the diagnostic process is to recognise the difference between teeth with a vital pulp and teeth without a vital pulp

Vital pulp therapy is normally initiated when a pulpitis, with or

without clinical symptoms, has been diagnosed Under certain circumstances, treatment of a non-inflamed vital pulp may be done due to restorative needs or when the pulp has been traumatically exposed Common for all these diagnostic conditions is the fact that the pulp tissue, in these circumstances, IS not infected but merely contaminated on the exposed tissue surfaces

Other teeth offered endodontic treatment are teeth with a necrotic pulp, teeth with pulp necrosis and apical periodontitis, and previously root-filled teeth with apical periodontitis

From a pathological point-of-view these diseases are very different from the diseases of the vital pulp They are all infectious diseases, and it is reasonable to suggest that teeth with these clinical diagnoses would therefore require different treatment regimens than when the pulp is vital

Unfortunately, for many in the profession, the treatment choice for teeth with a vital pulp as well as with a necrotic infected pulp and pulpless teeth is t o perform a “Root Canal” Thts is a low point in clinical sophistication Searching the literature for evidence to use as a scientific basis for treatment, using the term “Root Canal” will not be very helpful The treatment of an endodontic disease must always apply microbiological principles The treatment modalities that correspond to the disease process and the severity of the pathological conditions at hand must be better defined

Treatment When discussing the treatment of various pathological conditions

it is logical t o start with the less severe and proceed to the more complicated diseases

The vital pulp may need endodontic treatment due to accidental pulp exposures, clinical symptoms of pulpitis o r frank caries exposure There may also be situations where elective pulp therapy is instituted due to a restorative need for retention All these situations have as the common denominator that the pulp tissue is

vital and most often inflamed The pulp tissue, however, is not infected There may be surface contamination of bacteria, if there is

an ongoing carious process, but with an appropriate disinfection of the surgical field, before extirpating the pulp (9 ) the removal of the pulp is an aseptic micro-surgical procedure The pulp extirpation and the placement of the wound dressing - the root filling implant - should be completed in the one treatment sequence This is the perfect one-visit case This procedure done as a truly aseptic surgical procedure should have a successful outcome in more than 95% of the cases

When the pulp tissue becomes necrotic, infection of the necrotic pulp tissue and surrounding dentine follows (Fig I ) This is a more complex condition and therefore the therapeutic approach is very different from treating diseases of the vital pulp The connec- tion between bacteria and periapical lesions has already been

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Figure l Tooth with infected necrotic pulp A: Caries has penetrated into the pulp space and puip tissue is necrotic (Htx eosin) 6: Same tooth as in A but stained with Brown and Brenn for bacteria Dark areas are bacteria (Brown and Brenn) C: Magnification ofarea in 0 marked with an arrowhead Bacteria have invaded the dentine tubules (Brown and Brenn) D: Magnification ofarea indicated with an arrow in C The dentine body is heavily infected (Brown and Brenn)

established. Therefore, it is clear that the objective of the treatment must be the control of the root canal infection. When this has been achieved, the wound dressing, the root filling, can be placed. This is an antiseptic procedure using various antimicrobial agents to eliminate the disease-causing bacteria. It is well known from a number of earlier publications that regardless of the type of anti- microbial agent or its concentration, the root canal infection cannot be controlled predictably in one treatment session ( I 0). The key concept here is "predictable". Using the presently available best regimens of treating infected root canals, about one-third remain infected after one treatment session. Therefore, if root canal disinfection is the goal, the treatment of a tooth with an infected necrotic pulp is at least a two-visit procedure. The treatment of the tooth cannot be completed in one visit if the goal is t o provide an optimal treatment outcome for the patient.

This clearly demonstrates that there is a clear difference between "vital pulp therapy" and "infected pulp therapy". In modern studies, using optimal antimicrobial control, it has been shown that "infected pulp therapy", if done correctly, can be nearly as successful as "vital pulp therapy" ( 14).

There is a third diagnostic group that requires special treatment

consideration This is the previously root filled tooth with apical periodontitis This condition represents a clinical diagnosis that involves cases with very treatment-resistant infections The same study that suggested a 94% success rate when treating teeth with necrotic infected pulps, reported a 67% success rate in failed endodontically treated cases ( I 4) This significant difference suggests that there is something fundamentally different in this disease presentation compared to the tooth with a necrotic infected pulp There are probably inherent anatomical factors o r previous iatrogenic complications, which may negatively affect the prognosis of previously root-filled teeth However, major difference is to be found in the microbial complexity of the infection Table I shows the results from two different studies from the same clinical research group ( 13, 15) The microfiora identified when sampling from the root canals of root filled teeth that have failed is significantly different from the microflora found in teeth with a necrotic pulp and apical periodontitis This unusual group of microorganisms found in teeth with a failing root canal filling combined with the very low success rate of retreatment of these cases clearly identify a third category of endodontic cases that require special attention The bacteria identified in the root canals of failing root filled teeth are to a high degree Gram + cocci with an unusual concentration of E faecalis Another frequent finding is C albicans Several of these microbes are very resistant to calcium hydroxide which is the antimicrobial agent of choice when treating teeth with necrotic infected root canals Thus, many of the microbes found in these revision cases are highly resistant t o the conventional disinfection routine for infected root canals and may therefore require more thorough and extended treatment A predictable treatment routine has not yet been described for these cases, but it appears so far that more than one dressing with calcium hydroxide is required for a predictable d isi nfection

Thus it is easy to identify three different treatment routines for everyday endodontic treatment the treatment of the vital pulp, the necrotic pulp with infection, and the previously root filled tooth with apical pertodontitis

Table I : Microorganisms recovered from root canals. A lists bacteria in cultures taken before the root filling

of teeth with necrotic pulp and apical periodontitis, that have undergone routine instrumentation and

disinfection with Ca(OH),. "8" lists bacteria recovered from root canals of failed treatments after removal of the root filling. ( I 3, IS).

I 6 1 9

Culture occasion A B

Enterococcus faecalis

Steptococcus sp.

Lacto baci I Ius catenafor me

Propionibacterium sp.

Candida albicans

Peptostreptococcus sp.

Actinomyces sp.

Eubacterium sp.

Fusobacterium nucleatum

Bacteroides gracilis

Prevotella sp.

Campylobacter rectus

9

6

I

2

2 2 I

3 3 6 2 I I

I 3

2 I

-

~

~

-

~

-

-

14 AUSTRALIAN ENDODONTIC JOURNAL VOLUME 29 No I APRIL 2003

Evidence In the endodontic literature there are very limited scientific

sources to serve as an evidence base fot clinical decision rnaking Relevant material is in short supply There is an abundance of studies in vitro such as microbiological testing, technique testing and biomaterials testing In the area of microbiological testing there is

laboratory bench testing of antiseptics, chelators acids ancl other pharmaceuticals The clinical relevance of most of these studies is

unknown As an example, there is an excess of laboratory studies on smear layer removal with EDTA Clinically however, the relevance is not clear ( 16)

In regards to instrumentation there are hundreds of bench top experiments comparing hand and rotary instruments using various techniques, checking for transportation zipping and other mishaps However, there is no clinical information about the relevance of these technical issues It is unknown if any of these aesthetic concerns affect treatment outcome There is no controlled out- come study on the majority of these assumed important issues

Concerning the root filling itself there are laboratory tests of root filling methods, effects of various sealers, leakage patterns, and other aspects of what is depicted to represent quality It has not been established to what extent any of these factors have clinical relevance

Therefore it is easy to come to the conclusion that there is a

substantial shortage of good, controlled and unbiased cliriical studies to serve as an evidence base for clinical decision-making Too long have our resources been spent on laboratory testing, ofteq with very little clinical relevance There is now a need to turn the research focus towards good unbiased clinical trials Naturally, prospective studies are most valuable, but well done retrospective studies can also provide very valuable information Data obtained in such clinical studies should be carefully analysed with sound statistical methods in order to identify factors of importance for treatment outcome Then, having such information about seemingly important treatment factors, in vitro laboratory studies can be undertaken in an attempt to optimise these relevant treatment variables When optimised, these improvements can then be included in new clinical trials for verification and further observation These are the types of studies that will provide evidence and support for changes leading to better patient care At the present time, before more clinical information is available, there is little need for more leakage studies, root filling technique studies instrument transport studies and the like

Statistics Another important issue when analysing clinical or laboratory

data is the proper use of statistics Endodontic studies are all too often underpowered with much too small sample sizes Often a simple statistical calculation is made to arrive at the conclusion that no statistical difference exists. This is often done without first establishing if there is sufficient number of cases (power) in the study When a comparative study results in a statement of "there was no significant difference" the author should be obligated to provide a power analysis showing that the sample size is large enough to support such a statement. Much too often "no significant difference" is inconsequential and means nothing

Conclusion tndodontic textbooks and educational programmes are filled

with contradictory information leading to daily conflicts between fact

and fiction This makes clinical decision-making difficult because there is little objective evidence available as a base

There are however some basic facts to fall back on when providing endodontic treatment, which is based on the need for control or elimination of microorganisms in the endodontium It is

also easy to identify the three most common endodontic disease entities treated by the dentist They are the inflamed vital pulp, the primary infected root canal, and the infected pulp space of the previously root filled tooth To treat these widely disparate diseases with a one-size fits all procedure, "a root canal", is a great disservice to the patient and belittling to the profession These three conditions require different procedures and time allotments for optimal successful outcome

There is a dramatic shortage of controlled and relevant clinical studies where case selection, treatment factors and statistical methods have been satisfactorily controlled Greater emphasis should be placed on promoting such research with appropriate training and sufficient funding

References I , Kakehashi S., Stanley H.R., Fitzgerald R.J. The effects of surgical

exposures of dental pulps in germ-free and conventional laboratory rats. Oral Surg Oral Med Oral Pathol 1965; 20: 340- 9.

2. Sundqvist G. Bacteriological studies of necrotic dental pulps. Ume2 University Odontological Dissertations, 1976: 1-94,

3 . Dohlen G., Fabrious J . , Heyden G., Holm S.E., Moiler A.J.R. Apical periodontitis induced by selected bacterial strains in root canals of immunised and nonimmunized monkeys. Scand J Dent Res 1982; 90: 207- 16.

4. Fabrious J . , Dahlen G.. Holm S.E.. Moller A./.R. Influence of combinations of oral bacteria on periapical tissues of monkeys. Scand J Dent Res 1982; 90: 200-6.

5. Stashenko P, Yu S.M., Wong C Y Kinetics of immune cell and bone resorptive responses to endodontic infections, J Endod 1998; 18: 422-6.

6. Molander A, , Reit C., Dahlen G.. Kvist 7. Microbiological status of root-filled teeth with apical periodontitis. Int Endod J 1998; 31: 1-7.

7. Peciuliene V , Balouniene I . , Eriksen H.M., Haoposalo M. Isolation of Enterococcus faecalis in previously root-filled canals in a Lithuanian population. J Endod 2000; 26: 593--5.

8. Hancock 111 H.H., Sigurdsson A, , Trope M., Moiseiwitsch J . Bacteria isolated after unsuccessful endodontic treatment in a North American population. Oral Surg Oral Med Oral Pathol Oral Radiol tndod 200 I ; 9 I : 579-86.

9. Moiler AJ.R. Microbiological examination of root canals and periapical tissues of human teeth. Odont Tidskr 1966; 74: (no. 5 and 6).

0. Cvek M., Nord C.E.. Hollender L. Antimicrobial effect of root canal debridement in teeth with immature roots. A clinical and microbiologic study. Odont Revy 1976; 27: I - 10. Shuping G. € 5 , 0ntovik D., Sigurdsson A, , Trope M. Reduction of intracanal bacteria using nickel-titanium rotary instrumentation and various medications. J tndod 2000; 26: 75 1-5.

2. Bystrom A . , Sundqvist G. The antibacterial action of sodium hypochlorite and EDTA in 60 cases on endodontic therapy. Int Endod J 1985; 18: 35-40.

3. Sundqvist G.. Figdor D.. Persson S., Slogren U. Microbiologic analysis of teeth with failed endodontic treatment and the outcome of conservative re-treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998; 85: 86-93.

I

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14. Slogren U., Hiigglund B. . Sundqvist G.. Wing K. Factors affecting the long-term results of endodontic treatment. J Endod 1990; 16: 498-504.

15. Siogren U.. Figdor D.. Penson 8.. Sundqvist G. Influence of infection at the time of root filling on the outcome of endo-

dontic treatment of teeth with apical periodontitis. Int Endod J 1997; 30: 297-306.

16. Bystrom A. Evaluation of endodontic treatment of teeth with apical periodontitis. Umed University Odontological Disser- tations, Abstract 27, 1986; 1-42,

From The Journals Antibiotic Susceptibility Of Bacteria Associated With Endodontic Abscesses

Baurngartner/.C., Xia l./ Endodon 2002; 29: 44-7

Antibiotics to treat endodontic infections are routinely prescribed based on previously published susceptibility tests There is

increased concern that bacteria have increased resistance to the currently recommended antibiotics The purpose of this investigation was to perform antibiotic susceptibility tests on a panel of bacteria recently isolated from endodontic infections The bacteria in this study were aseptically aspirated with a needle from endodontic abscesses, cultivated, and identified at the species level Each of the 98 species of bacteria was tested for antibiotic

susceptibility to a panel of six antibiotics using the Etest The percentages of susceptibility for the 98 species were penicillin V 83/98 (85%) amoxycillin 89/98 (9 I %), amoxycillin + clavulanic acid 98/98 ( I OO%), clindamycin 94/98 (96%), and metronidazole 44/98 (45%) Metronidazole had the greatest amount of bacterial resistance, however, if it is used in combination with either penicillin V or amoxycillin, susceptibility of the combination with penicillin V or amoxycillin increased to 93% and 99%, respectively Clarithromycin seems to have efficacy, but it is still considered an antibiotic under investigation because the minimum inhibitory concentration has not been established

I s Pulpitis Painful?

Michaelson PL., Holland G.R. Int Oldod] 2002; 35: 829-32. enced pain or no pain from the involved tooth. Approximately 40% of the teeth included gave no history of spontaneous or prolonged pain to a thermal stimulus. No statistically significant differences in the incidence of "painless pulpitis" were related to either gender or tooth type. Patients aged >53 years experienced "painless pulpitis" more often than patients <33 years. Many teeth appear to progress to pulpal necrosis without the patient experiencing pain attributable to the pulp.

The aim of this study was to determine whether inflamed dental pulps progress to necrosis without pain. Records of 2,202 maxillary anterior teeth endodontically treated at the University of Michigan were collected. Records of teeth presenting with periapical radio- lucencies but no response to vitality tests were examined further to determine, from the history, whether the patient had experi-

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