This study compares two commonly used intracanal medicaments-Triple Antibiotic Paste and Calcium Hydroxide-in patients with infected single-rooted teeth. The purpose is to determine which medicament promotes faster healing of periapical lesions after root canal treatment by measuring reduction in lesion size and improvement in bone density over 3, 6, and 12 months.

This single-center, parallel-arm, randomized controlled trial aims to directly compare the efficacy of Triple Antibiotic Paste (TAP) and Calcium Hydroxide (CH) as intracanal medicaments on the rate of healing of periapical lesions in single-rooted teeth. Systemically healthy adults (18-65 years) with a diagnosis of pulpal necrosis and asymptomatic apical periodontitis or chronic apical abscess, presenting with a radiographically evident periapical radiolucency (≥2mm), will be enrolled. Following informed consent, chemomechanical preparation, and randomization, participants will receive either TAP (Ciprofloxacin:Metronidazole:Minocycline) or CH as the intracanal medicament. The primary outcome is the rate of healing, quantified by the percentage reduction in periapical lesion area and improvement in bone density scores assessed on standardized periapical radiographs or CBCT scans at 3, 6, and 12-month follow-ups. Secondary outcomes include clinical resolution (absence of pain, tenderness, sinus tract) and radiographic resolution (restoration of normal periapical architecture). Data will be analyzed using intention-to-treat analysis, with repeated-measures ANOVA to compare healing trajectories between groups.

Inclusion Criteria:

• Systemically healthy adult patients between 18 and 65 years of age.

Presence of a single-rooted tooth diagnosed with pulpal necrosis and asymptomatic apical periodontitis or chronic apical abscess.

Radiographic evidence of a distinct periapical radiolucency with a minimum diameter of 2mm.

The involved tooth must be deemed restorable after endodontic treatment.

Patient willingness and ability to provide informed consent and comply with the follow-up schedule

Exclusion Criteria:

Patients under 18 or over 65 years of age.

Presence of systemic diseases known to affect bone metabolism or immune response (e.g., uncontrolled diabetes).

Pregnancy or lactation.

Known allergies to any components of Triple Antibiotic Paste or calcium hydroxide.

Teeth with previous root canal treatment, internal/external root resorption, root fractures, or non-endodontic periapical pathology.Exclusion Criteria:

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