Dental caries is a significant global health issue, often leading to pulp necrosis and infection in primary
teeth. Traditional pulpectomy procedures face limitations due to complex root anatomy and patient
cooperation, prompting the search for alternative treatments. This study compares the effectiveness of
Lesion Sterilization and Tissue Repair (LSTR) using a modified 3Mixed-MP mortal pulpotomy (ciprofloxacin,
metronidazole, amoxicillin in macrogol-propylene glycol) versus conventional formocresol for treating
pulpitis and periapical lesions in primary molars. A split-mouth randomized clinical trial was conducted on
fifteen children with bilateral non-vital mandibular primary molars. One molar received formocresol
treatment while the opposing tooth was treated with the modified 3Mixed-MP mortal pulpotomy. Clinical
parameters-pain, swelling, mobility-and radiographic measures of root length and bone density were
evaluated at 1-, 3-, and 6-months post-treatment. Both therapies resulted in high clinical success and
symptom resolution at 6 months. Formocresol offered slightly higher success rates for pain relief and bone
density improvement (86.7%) compared to 3Mix-MP (60%), but both treatments preserved root integrity
without marked resorption. The 3Mix-MP technique exhibited transient inflammatory signs, yet its minimally
invasive nature and shorter procedure time make it advantageous for uncooperative pediatric patients.
Survival analysis indicated longer-lasting benefits for formocresol. In summary, dual-antibiotic LSTR
(3Mixed-MP) presents a viable, less traumatic option for managing infected primary molars. Further
research is recommended to optimize antibiotic protocols and enhance long-term outcomes for pediatric
endodontic care.