INTRODUCTION:

Management of teeth with infected root canal or any other periapical pathologies, serves to be a challenging aspect of endodontic procedures in both primary as well as permanent tooth. The major purpose of endodontic treatment is to reduce the viability of microbes and other noxious substances in the root canal system(1). Infected root canal is mainly composed of microbial flora of both aerobic and anaerobic organisms, but predominantly anaerobic bacteria, which was removed either by mechanical means (dentin removal) or by chemical means (irrigation)(2). Thus the research unit of the school of Dentistry, Niigata University, Japan to develop the concept of Lesion sterilization and tissue repair(LSTR) therapy, which is an alternative procedure to pulpectomy(3).

Lesion sterilization and tissue repair (LSTR) is a non-instrumentation endodontic treatment that employs a mixture of antibacterial drugs in a propylene glycol vehicle for the purpose of disinfection(4). In recent days, the concept of revascularization of the necrotic pulps became an alternative conservative treatment to the traditional apexification procedures with calcium hydroxide. Thus, use of proper antibiotic as a sterilizing agent might ensure additional success rate of the procedure. LSTR employs a combination of three antibacterial drugs for the purpose of disinfection(5).

Endodontic regenerative procedure:

LSTR is an advancement of Endodontic regenerative procedure(ERP). In ERP, conventional treatment using either minimal or no instrumentation is done. This treatment protocol involves the use of Triple antibiotic paste, followed by placement of intracanal medicament and later inducing bleeding from the periapical region. The bleeding would lead a matrix for movement and growth of new vital tissues in root canal spaces(6). The triple antibiotic pastes generally used includes, metronidazole, minocycline and ciprofloxacin(7, 8).

LESION STERILIZATION AND TISSUE REPAIR:

As discussed, LSTR is placing antibiotics inside the infected pulp chamber. The therapy aims to eliminate the causative bacteria from the lesion and thus sterilizing the lesion promoting tissue repair and regeneration by host’s natural healing processes(9). Regeneration and tissue revascularization mainly depends on the criteria, which includes, disinfection of the canal, placement of matrix inside the canal for tissue in growth and a bacterial sight seal of the access opening(10). Thus, recommended protocol combines the use of metronidazole, minocycline and ciprofloxacin(11).

LSTR- INDICATIONS:

All indications of pulpectomy

Primary tooth associated with pain and tenderness to percussion

Presence of mobility, abscess, sinus tract, radiolucency in furcation areas

Restorable crowns

Immature permanent tooth with incomplete root formation. (38)

CONTRAINDICATIONS:

In case of patients who are sensitive and allergic to any of the antibiotic companies that

Excessive bone loss in furcation areas involving the underlying tooth germ(38)

TRIPLE ANTIBIOTIC PASTE:

Three antibiotics used in triple antibiotic paste includes ciprofloxacin, minocyclin and metronidazole in the ratio of 1:1:1. These are mixed and the combination ensures the complete eradication of all types of microbial flora in the root canal orifice. The triple antibiotic paste is formed by mixing the three antibiotic powder with macrogol or propylene glycol which possess the property to penetrate into the antimicrobial compound. Thecommercially available triple antibiotic paste is 3-MIX MP usually supplied as a two-part system wherein the dry powder component contains metronidazole, ciprofloxacin, minocycline and iodoform. The liquid component contains polyethylene glycol and macrogol. The components are mixed prior to use(17).

Since, it is radiolucent in nature, Iodoform was added to the triple antibiotic paste to make it radio opaque and thus promoting radiographic confirmation of the proper paste placement(13). An in-vitro study conducted by Hoshino et al. testing the antibacterial effect resulted that no drug individually eliminated the microbial flora, but as a combination these drugs were consistently able to ensure proper sterilization. The minimal drug dosage is 100mg/dl(14).

Ciprofloxacin is a synthetic fluroquinone possessing bactericidal mode of action. Metronidazole is a nitroimidazole compound exhibiting a broad spectrum activity against protozoa and anaerobic bacteria. Minocycline is a semisynthetic derivative of tetracycline possessing a mode of action similar to metronidazole(16).

METHOD OF PREPARATION:

Clean mortar and pestle are taken in which each tablet, after the removal of enteric coating, will be placed and ground to fine powder. To required quantity of tablet powder, sufficientquantity of polyethylene glycol is added to result a creamy paste(18).

STORAGE:

Resultant opaque paste is usually stored in air-tight containers for future use. Iodoform is the agent which ensures radio opacity, therefore change in translucency from opacity indicated contamination which should not be used(19).

DOSAGING:

Ciprofloxacin; metronidazole; minocycline (In a ratio of 1:1:1) along withsmall quantities of iodoform in the powder and propylene glycol or macrogol or along with normal saline as a carrier(20).

OTHER COMBINATIONS OF TAP:

Fabricus et al. used Metronidazole and ciprofloxacin plus amoxicillin. They also tried Metronidazole and ciprofloxacin plus rokitamycin(21)

Haapasalo et al. used Metronidazole and ciprofloxacin plus ceflaclor (22)as combination.

Metronidazole and ciprofloxacin plus clindamycin(23) was used by Grossman et al.

Fouad et al took the combination of Metronidazole and ciprofloxacin plus fosfomycin (24).

A combination of penicillin, bacitracin or chloramphenicol and streptomycin is generally termed as Grossman’s polyantibiotic paste(23).

A combination of Chlorhexidine pastes are used by Filho JH et al(25).

CLINICAL PROCEDURE:

Clinical signs and symptoms are generally recorded. At first, preoperative radiograph is takenfollowed by which anesthesia is achieved, tooth is isolated under rubber dam or by cotton pellets, caries removal is preferred followed by access cavity preparation, then the necrotic coronal pulp is extirpated, the canal is later filled withtriple antibiotic paste, teeth is then sealed with glass ionomer cement or IRM and final restoration is done with stainless steel crowns(26, 27)

RELATED STUDIES ON LSTR-DISCUSSION:

Akgun et al (2009) used triple antibiotic paste as a disinfectant for traumatize immature tooth with a periapical lesion and found that after 4 months, the patient had no symptoms, and a radiograph showed the radiolucency had completely resolved. (28)

Reynolds et al. achieved revascularization of a necrotic bicuspid using triple antibiotic paste, which contains both bactericidal (metronidazole, ciprofloxacin) and bacteriostatic (minocycline) agents to allow for revascularization. (29)

Tauksheje et al(2004) evaluated the effectiveness of LSTR in primary teeth. They found that in 87 cases after a follow up period of 680 days found that infected primary teeth were relieved of symptoms such as abscess, gingival fistulae and pain and the teeth remained asymptomatic until their exfoliation. (30)

Prabakar et al (2008) evaluated clinical and radiographic success of endodontic treatment of infected primary teeth using combination of ciprofloxacin, metronidazole, and minocycline. (31)

Manisha Agaerwal et al (2011)8 assessed the efficacy of LSTR and pulpotomy against the conventional pulpectomy treatment. They concluded that LSTR and pulpotomy were effective but long term follow up is needed for LSTR to consider its efficacy(32)

Jaya et al (2012) evaluated and compared the clinical and radiographic effectiveness of Ciprofloxacin, Minocycline, Metronidazole combination with Ciprofloxacin, Minocycline and Tinidazole combination when used for Lesion Sterilization and Tissue Repair in primary teeth. (33)

Sato et al investigated this drug combination in vitro and established it to be very effective in the decontamination of deep caries, necrosed pulp, and infected root canals of primary teeth. (34)

Hoshino et al determined that a combination of ciprofloxacin, metronidazole, and minocycline with a dilution of 25g each per millilitre of paste has ability to decontaminate infected root canal dentin in vitro. (14)

Banchs F et al suggested that the MIC method may not be suitable for determining whether combinations of drugs can kill all the bacteria in a flora. (35)

Ozan U1and Er K reported on endodontic treatment of a large cyst-like periradicular lesion using a combination of antibiotic drugs. (36)

Ozlem reported on use of triple antibiotic paste for a traumatized immature tooth with a periapical lesion. (37)

ADVANTAGES OF LSTR:

Easy and simple, one visit technique, painless and economical(38)

No instrumentation needed(39)

No irritation of the periapical tissues

No obturation required (40)

DISADVANTAGES OF LSTR:

The main drawback of tripleantibiotic paste isbluish-grey hue producing tooth discolouration due to drug of tetracycline family which produces photo induced reaction. It is generally overcome by the replacement of minocycline with clindamycin, thus preventing staining and discolouration.(41) Some studies have also suggested the complete elimination of tetracycline family of drugs so as to prevent staining disadvantages.

Other drawback is radiolucency which is overcome by the addition of trace amounts of iodoform to the powder component(42).

CONCLUSION:

The Lesion sterilization and tissue repair therapy is simple, painless, time-saving, and with less of a burden to patient physically and mentally. Thus, patient compliance and cooperation of patients is predicable, which is of great concern in the management of Pediatric patients. This procedure will disinfect the severely infected deciduous teeth and allow it to function as a natural space maintainer until the eruption of its permanent successor(43). This new concept should be considered especially in cases where prognosis is poor with the conventional pulpectomy procedure in primary teeth with furcation involvement and severe bone loss.

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Received on 04.02.2017 Modified on 20.03.2017

Research J. Pharm. and Tech. 2017; 10(5): 1539-1542.

DOI: 10.5958/0974-360X.2017.00271.2