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dentist explaining lesion sterilization and tissue repair (LSTR) with triple antibiotic paste

Lesion Sterilization and Tissue Repair (LSTR)

dentist explaining lesion sterilization and tissue repair (LSTR) with triple antibiotic paste

Lesion Sterilization and Tissue Repair (LSTR)

Lesion sterilization and tissue repair (LSTR) is an alternative to extracting primary teeth in cases of gross periradicular pathosis and internal resorption. LSTR involves the use of a triple antibiotic paste to treat the infection that is causing the inflammation and retreat of tissue. Avoiding tooth extraction can be a great benefit for patients and practitioners and help extend the longevity of a child’s teeth. LSTR with triple antibiotic paste is an effective, proven method to keep primary teeth while avoiding the use of traditional endodontic methods. The triple antibiotic paste can be made in two different formulations by our compounding pharmacy that each have slightly different ingredients.

Using Multiple Antibiotics for Lesion Sterilization and Tissue Repair

A single antibiotic is not sufficient to sterilize the root canal and periradicular region. Even though the majority of bacteria responsible for infection in the root canal are anaerobic, it is essential to eliminate both aerobic and anaerobic bacteria to ensure tissue can be repaired. A combination of antibiotic ingredients used together is more likely to eliminate infection that is caused by a mixture of different types of bacteria. Another benefit of using multiple drug ingredients is that the combination helps reduce the chances of developing resistant bacterial strains.

This combination of needs – having a product that provides broad-spectrum antibacterial properties while also not encouraging bacterial resistance – was the impetus for the development of a triple antibiotic paste. Case reports and studies that have been published in subsequent years showed repeated success with a combination antibiotic product containing metronidazole, minocycline, and ciprofloxacin. Dentists now frequently request this formulation from our compounding pharmacy.

Triple Antibiotic Paste (3-Mix) Ingredients

These are the ingredients in the original formulation proposed by Sato et al in their 1996 study, which since has been consistently used with some variations.

Metronidazole – Narrow spectrum antimicrobial that is effective against gram-positive and gram-negative organisms.

Minocycline – Broad spectrum antimicrobial that is effective against gram-positive and gram-negative organisms.

Ciprofloxacin – Narrow spectrum antimicrobial that is effective against gram-positive organisms.

Macrogol/Propylene Glycol (MP) Paste – The MP paste acts as a solvent to improve penetration of the antibiotics into the dentinal tubules.

Dentists will sometimes use clindamycin in place of minocycline, as tetracycline antibiotics have a tendency to stain teeth a bluish-gray color. The alternate formulation for LSTR uses clindamycin instead of minocycline. This formulation also includes iodoform, which makes the triple antibiotic paste radio-opaque. The antibiotic paste on its own without iodoform is radiolucent. In our formulations we combine the three antibiotics in a roughly 1:1:1 ratio, although other ratios have been used. Both formulations are made in a macrogol and propylene glycol paste.

Triple Antibiotic Paste for LSTR – Formulation 1

Metronidazole 33%, Minocycline 34%, Ciprofloxacin 33%

Triple Antibiotic Paste for LSTR – Formulation 2

Metronidazole 30%, Clindamycin 30%, Ciprofloxacin 30%, Iodoform 10%

Success of LSTR

If LSTR is successful then the infection is eliminated and tissue is naturally repaired. In the study by Takushige et al, triple antibiotic paste was used to treat 87 primary teeth, 81 of which had physiologic root resorption. The treatment was successful for the majority of patients. Symptoms of gingival swelling, sinus tracts, induced and spontaneous dull pain, and pain on biting were reduced in all but a few cases. These few patients resolved after a re-treatment with the same procedure. In addition, the study noted that all patients later had healthy, normal successor teeth.

Other research has confirmed that LSTR is a simple and painless procedure with significant benefits for pediatric patients. A retrospective study was conducted of 54 cases that used endodontic regenerative procedures and 40 control cases. The study found that triple antibiotic paste “produced significantly greater differences in root wall thickness than either the Ca(OH)(2) or formocresol groups (P < .05 for both).” This study showed that triple antibiotic paste used in primary teeth can effectively promote development of the pulp-dentin complex.

LSTR and Compounding

It has been well-established that periradicular pathosis is primarily caused by bacterial infection. Triple antibiotic paste provides broad-spectrum treatment for this type of infection. It can be used for most patients with primary teeth, with the exception of those who have a documented allergy to any of the ingredients. Currently there are no commercially available preparations that include three antibiotics in an appropriate delivery vehicle for LSTR. However both 3-Mix formulations can be made by our compounding pharmacy.

The triple antibiotic paste is supplied in two parts to improve stability and effectiveness of the formulation. A powder containing the three antibiotics is supplied in one syringe, while the macrogol/propylene glycol material is supplied in a separate syringe. The two syringes are combined in the office immediately before the LSTR treatment. Unprepared medication can be stored for up to 6 months in the refrigerator. However, once combined, the paste should be used within 5 days.

Dentists throughout the country choose Woodland Hills Pharmacy for their compounding needs. To learn more about how to order triple antibiotic paste for lesion sterilization and tissue repair, call our pharmacy at (855) 876-3060 or contact us here.


Efficacy of Lesion Sterilization and Tissue Repair in Primary Tooth with Internal Resorption: A Case Series – Contemporary Clinical Dentistry

Endodontic treatment of primary teeth using a combination of antibacterial drugs. – International Endodontic Journal

A retrospective evaluation of radiographic outcomes in immature teeth with necrotic root canal systems treated with regenerative endodontic procedures. – Journal of Endodontics

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