Lesion Sterilization Tissue Repair and Conventional Pulpectomy in Primary Molars

This ambidirectional cohort study evaluates the clinical and radiographic outcomes of conventional pulpectomy and lesion sterilization tissue repair (LSTR) in children aged 3-8 years treated at the Department of Pediatric Dentistry, Faculty of Dentistry, Çanakkale Onsekiz Mart University. The study includes mandibular primary molars diagnosed with pulp necrosis or irreversible pulpitis that meet the predefined eligibility criteria.

The null hypothesis is that there is no significant difference in clinical and radiographic success between conventional pulpectomy and LSTR at the evaluated follow-up periods.

The required sample size was calculated based on parameters derived from the study by Moura et al., which compared the clinical and radiographic success of conventional root canal treatment using zinc oxide eugenol with LSTR using a triple antibiotic paste. With a power of 80%, an alpha error probability of 0.05, and an effect size of 0.4020915, the required sample size was calculated using G*Power (version 3.1.9.7; Universität Kiel, Kiel, Germany) as 37 participants per group.

The study cohorts were formed from patients whose mandibular primary molars had previously received either conventional pulpectomy using a calcium hydroxide-iodoform-based root canal filling paste or LSTR using a triple antibiotic paste containing metronidazole, ciprofloxacin, and clindamycin. All treatments were performed by the same operator according to standardized clinical protocols. Eligible previously treated cases were identified separately for each treatment modality, and participants included in the study were randomly selected from the respective eligible treatment pools. Treatment allocation was not performed as part of the research protocol.

The common procedural steps for both treatment modalities included initial clinical and radiographic examination; mandibular alveolar nerve block anesthesia using lidocaine hydrochloride with a vasoconstrictor; rubber dam isolation; removal of carious enamel and cavity preparation using sterile diamond fissure and round burs under water cooling; complete removal of carious dentin and the roof of the pulp chamber; removal of coronal pulp tissue; and irrigation of the pulp chamber with sterile saline.

LSTR cohort:

For LSTR, a triple antibiotic paste containing metronidazole, ciprofloxacin, and clindamycin was used. Minocycline, which has historically been included in triple antibiotic formulations, was excluded because of concerns regarding discoloration associated with tetracycline derivatives and recommendations favoring non-tetracycline antibiotic combinations for non-vital pulp therapy in primary teeth.

The enteric coatings of tablets and capsule shells were removed, and each drug was ground separately into a fine powder using a mortar and pestle. The powders were stored separately in tightly sealed containers protected from light and moisture. Equal quantities of each powder were measured using a precision balance and combined in a 1:1:1 ratio. Equal proportions of propylene glycol and macrogol were used as the liquid vehicle, and the antibiotic powders and vehicle were combined at a 7:1 powder-to-liquid ratio.

The canal orifices were enlarged by approximately 1-2 mm using a small low-speed round bur, and the walls of the pulp chamber were chemically cleaned with phosphoric acid for one minute. After rinsing with sterile saline and drying with cotton pellets, the triple antibiotic paste was applied to the canal orifices and pulp chamber floor. The pulp chamber was sealed with glass ionomer cement, and the tooth was restored with a stainless steel crown.

Pulpectomy cohort:

For conventional pulpectomy, root length was determined using diagnostic radiographs. The root canals were enlarged by 2-3 file sizes beyond the initial file size using K-type endodontic files. During instrumentation, irrigation with 2 mL of 2.5% sodium hypochlorite (NaOCl) was performed after each file. Following canal preparation, the canals were irrigated with 2.5% NaOCl followed by saline and dried using paper points. The canals were then filled with a calcium hydroxide-iodoform paste. The pulp chamber was sealed with glass ionomer cement, and the tooth was restored with a stainless steel crown.

Postoperative periapical radiographs were obtained following treatment. The selected cohorts are being followed longitudinally for clinical and radiographic outcomes. Clinical evaluations are performed at 1, 3, 6, 9, 12, 18, 24, 30, and 36 months, and radiographic evaluations at 3, 6, 12, 18, 24, 30, and 36 months. The 12-month follow-up has been completed, while longer-term follow-up of the established cohorts is continuing.