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.

• Lesion sterilization and tissue repair (Procedure): Lesion sterilization and tissue repair therapy performed with a triple antibiotic mixture.
• Conventional pulpectomy (Procedure): Conventional pulpectomy with calcium hydroxide-iodoform based root canal paste.

Primary outcomes

• Clinical success [Follow up will be for three year with recall visits at 1, 3, 6, 12, 18, 24, 30 and 36 months.]: * Absence of spontaneous pain. * Absence of sensitivity to percussion using dental mirror, pain on biting. * Absence of swelling. * Absence of fistula / Exudate. * Absence of non-physiological mobility
• Miller Classification - Tooth Mobility [1, 3, 6, 12, 18, 24, 30, and 36 months.]: Class 0 Normal (physiologic) movement when force is applied. Class I Mobility greater than physiologic. Class II Tooth can be moved up to 1mm or more in a lateral direction (buccolingual or mesiodistal). Inability to depress the tooth in a vertical direction (apicocoronal). Class III Tooth can be moved 1mm or more in a lateral direction (buccolingual or mesiodistal). Ability to depress the tooth in a vertical direction (apicocoronal).
• Radiographic success [Follow up will be for three year with recall visits at 1, 3, 6, 12, 18, 24, 30 and 36 months.]: * Absence of furcation or periapical radiolucency. * Absence of change in the extent of internal or external root resorption other than physiologic resorption.

Sex: All, ages: 3 Years to 8 Years, accepts healthy volunteers

Inclusion Criteria:

* The participant is between the ages of 3 and 8 years.
* The participant and their parent(s) have signed informed consent forms agreeing to participate in the study.
* The patient is systemically healthy.
* The patient's cooperation level is sufficient for performing the procedures.
* No history of allergic reactions to the materials and substances to be used.
* Mandibular primary molars diagnosed with pulp necrosis or irreversible pulpitis.
* Presence of endodontic-origin gingival abscess or fistula in the involved teeth.
* History of spontaneous pain.
* Presence of radiolucency in the furcation or periapical region, not exceeding one-third of the affected area.
* Presence of deep dentin caries causing pulp exposure.
* Presence of mobility at level 0 or 1 according to Miller's classification (non-pathologic).
* The tooth meets the criteria for restorability.
* Root resorption does not exceed more than four-fifths of the root.
* The tooth meets the criteria for isolation.

Exclusion Criteria:

* The participant is not between the ages of 3 and 8 years.
* The participant and/or their parent(s) have not agreed to participate in the study or have not signed the informed consent forms.
* The patient has a systemic disease.
* The patient's cooperation level is insufficient to perform the procedures.
* The patient has a history of allergic reactions to the materials and substances to be used.
* Teeth with external or internal root resorption.
* Mechanical or carious perforation of the pulp floor in the affected teeth.
* Radiolucency and bone destruction in the furcation or periapical region exceeding one-third of the affected area.
* Presence of caries that does not cause pulp exposure.
* Pathological mobility according to Miller's classification (>1 score).
* The tooth does not meet the criteria for restorability.
* Root resorption exceeds more than four-fifths of the root.
* The tooth does not meet the criteria for isolation.

• Sümeyye Şenol, R.A., Principal investigator, Çanakkale Onsekiz Mart University
• Berkant Sezer, Assoc. Prof., Principal investigator, Çanakkale Onsekiz Mart University