Latest concepts in root canal treatment

ABSTRACT This paper highlights one aspect of a presentation to be given at the BDA Conference and is written in the context of dentistry in primary care. Careful oral health assessment as a

foundation to good treatment planning and quality dentistry is not new, but there are a number of important new perspectives emerging across countries and healthcare systems in terms of the

content and role of such an assessment in modern dental practice. You have full access to this article via your institution. Download PDF MAIN It has been known for 40 years that

micro-organisms play an indispensable role in the pathogenesis of periradicular disease.1 Seminal studies by Moller _et al_,2 Fabricius _et al_3 and Sundqvist,4 using culturing techniques,

showed that the bacteria present in the infected root canal system were mainly obligate anaerobes with smaller numbers of facultative anaerobes. The microflora are varied and interdependent

and are present within the necrotic dental pulp and the root canal wall, where they form a complex biofilm. Penetration into the dentinal tubules may occur. These are areas where the host

defence mechanisms are lacking. If the latter is compromised, or the micro-organisms are particularly virulent, then invasion of the periradicular tissues may occur. Yeasts and viruses may

also be involved with the infective process.5 In the last few years it has been demonstrated that the microflora may be even more diverse. Using molecular genetic techniques uncultivatable

bacteria have been detected.6,7 In addition, teeth with failed root canal treatments may have a different and more resistant flora from _de novo_ cases thereby making success in root canal

retreatment more difficult to achieve.8 The purpose of root canal treatment is to clean the root canal system of as many pathogens as possible, seal the system to prevent re-infection and

allow healing to take place. This must be done without compromising the long-term function of the tooth. Shaping the root canal allows cleaning to be undertaken more efficiently as well as

providing a suitable shape to obturate the system effectively. The use of nickel titanium rotary instruments allows predictable shapes to be achieved, even in curved root canals. This super

elastic alloy has enabled manufacturers to produce instruments of varying taper which can allow improved cleaning. Cleaning is achieved with chemical solutions and sodium hypochlorite

(NaOCl) is still the most popular. Removal of the smear layer is considered now to be necessary and a chelating agent such as ethylene diamine tetra acetic acid or citric acid is suitable. A

new irrigating solution (MTAD) has shown promising results as an antimicrobial cleaning agent.9,10,11,12 The apical extent of the root filling influences success. The interface between the

periradicular tissues and the pulpal tissues can be determined by electronic apex locators and when used with a precise technique are accurate and reproducible. There has been some

controversy concerning the diameter of the apical preparation. Some authorities consider that dentine should be removed apically to remove contamination whilst others consider that a narrow

preparation, combined with a suitable flare to allow irrigant penetration is satisfactory.13,14,15,16 The use of a single visit or multiple visits in root canal treatment continues to

generate controversy. Certainly, reversible pulpitis cases can be predictably treated in a single visit but it may be that in cases where there is apical infection that the root canal system

should be dressed with an anti microbial agent prior to obturation.17 The use of heated gutta-percha for obturation is now commonly accepted (Fig. 1). However, gutta-percha has no effect on

the physical properties of the tooth, and materials have been introduced that are said to increase the strength of the tooth root by bonding to the dentine and forming a monobloc. Early

tests suggest that these resin materials may have a place in endodontic obturation.18 When the root canal system has been obturated it is important to protect it from subsequent microbial

contamination. Thus the coronal seal is an important consideration during root canal treatment.19 High success rates can be expected. Should re-treatment be necessary, then a surgical

approach may be adopted if it is difficult or impossible to reach the apical part of the root canal system from the crown of the tooth. The introduction of microsurgical techniques has

transformed this procedure and the use of mineral trioxide aggregate as a root end filling ensures that a bioactive healing response may be predicted.20 The continued advances in the

understanding of the aetiology and treatment of periradicular periodontitis will allow clinicians to achieve more predictable success rates in root canal and root canal re-treatment. The

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VISIT: WWW.BDA-EVENTS.ORG REFERENCES * Kakehashi S, Stanley HR, Fitgerald RJ . The effects of surgical exposures of dental pulps in germ-free and conventional laboratory rats. _Oral Surg

Oral Med Oral Pathol_ 1965; 20: 340–349. Google Scholar  * Moller AJ, Fabricius L, Dahlen G, Ohman AE, Hayden G . Influence on periapical tissues of indigenous oral bacteria and necrotic

pulp tissue in monkeys. _Scand J Dent Res_ 1981; 89: 475–484 PubMed  Google Scholar  * Fabricius L, Dahlen G, Ohman A E, Moller AJR . Predominant indigenous oral bacteria isolated from

infected root canal after varied times of closure. _Scan J Dent Res_ 1982; 90: 134–144. Google Scholar  * Sundqvist G Bacteriological studies of necrotic dental pulps (Dr Odont thesis) Umea,

Sweden: University of Umea 1976. * Peciuliene V, Reynaud, AH, Balciuniene, I, Haapasalo, M . Isolation of yeasts and enteric bacteria in root-filled teeth with chronic apical periodontitis.

_Int Endod J._ 2001; 34: 429–434. Article  Google Scholar  * Rolph H J, Lennon A, Riggio MP, Saunders WP, MacKenzie D, Coldero Bagg J . Molecular identification of micro-organisms from

endodontic infections. _J Clin Microbiol_ 2001; 39: 3282–3289. Article  Google Scholar  * Munson M A, Pitt-Ford T, Chong B, Weightman A, Wade W G . Molecular and cultural analysis of the

microflora associated endodontic infections. _J Dent Res_ 2002; 81: 761–766. Article  Google Scholar  * Molander A, Reit C, Dahlen G, Kvist T . Microbiological status of root-filled teeth

with apical periodontitis. _Int Endod J._ 1998; 31: 1–7. Article  Google Scholar  * Torabinejad M, Shabahang S, Aprecio R, Kettering JD . The antimicrobial effect of MTAD: an in vitro

investigation. _J Endod_ 2003; 29: 400–403. Article  Google Scholar  * Shabahang S, Pouresmail M, Torabinejad M . In vitro antimicrobial efficacy of MTAD and sodium hypochlorite. _J Endod_

2003; 29: 450–452. Article  Google Scholar  * Torabinejad M, Cho Y, Khademi AA, Bakland LK, Shabahang S . The effect of various concentrations of sodium hypochlorite on the ability of MTAD

to remove the smear layer. _J Endod_ 2003; 29: 170–175. Article  Google Scholar  * Park D S, Torabinejad M, Shabahang S . The effect of MTAD on the coronal leakage of obturated root canals.

_J Endod_ 2004; 30: 890–893. Article  Google Scholar  * Card S J, Sigurdsson A, Orstavick D, Trope M . The effectiveness of increased enlargement in reducing intracanal bacteria. _J Endod_

2002; 28: 779–783. Article  Google Scholar  * Wu MK, Wesselink PR, Walton RE . Apical terminus location of root canal treatment procedures. _Oral Surg Oral Med Oral Pathol Oral Radiol Endod_

2000; 89: 99–103. Article  Google Scholar  * Coldero L G, McHugh S, MacKenzie D, Saunders WP . Reduction in intracanal bacteria during root canal preparation with and without apical

enlargement. _Int Endod J_ 2002; 35: 437–446. Article  Google Scholar  * Siqueira Junior JF, Lima KC, Magalhaes FA, Lopes HP, de Uzeda M . Mechanical reduction of the bacterial population in

the root canal by three instrumentation techniques. _J Endod_ 1999; 25: 332–325. Article  Google Scholar  * Nair PNR, Henry S, Cano V, Vera J . Microbial status of apical root canal system

of human mandibular first molars with primary apical periodontitis after “one-visit” endodontic treatment. _Oral Surg Oral Med Oral Pathol Oral Radiol Endod_ 2005; 99: 231–252. Article 

Google Scholar  * Teixeira FB, Teixeira EC, Thompson JY, Trope M . Fracture resistance of roots endodontically treated with a new resin filling material. _J Am Dent Assoc_ 2004; 135:

646–652. Article  Google Scholar  * Saunders WP, Saunders EM . The root filling and restoration continuum - prevention of long term endodontic failure. _Alpha Omegan_ 1997; 90: 40–46. PubMed

  Google Scholar  * Koh ET, McDonald F, Pitt Ford TR, Torabinejad M . Cellular response to Mineral Trioxide Aggregate. _J Endod._ 1998; 24: 543–547. Article  Google Scholar  Download

references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Professor of Dental Health, University of Dundee's Dental Health Services Research Unit, Community Health Sciences, Mackenzie

Building, Kirsty Semple Way, Dundee, DD2 4BF W Saunders Authors * W Saunders View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS

Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Saunders, W. Latest concepts in root canal treatment. _Br Dent J_ 198, 515–516 (2005). https://doi.org/10.1038/sj.bdj.4812297

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