Background <p>The aim of this study is to evaluate the effects of direct pulp capping and coronal pulpotomy treatments on root development (apexogenesis) and treatment success in immature mandibular first permanent molars with symptoms of reversible pulpitis.</p> Methods <p>The study included 72 immature mandibular first molars from 60 children aged between 7 and 10 years who applied to the Department of Pediatric Dentistry, Faculty of Dentistry, Ataturk University. Pulpotomy was performed on 34 teeth and direct pulp capping on 38 teeth. In all cases, a single biomaterial (ProRoot MTA) was used, and treatments were completed in a single visit. Clinical and radiographic follow-ups were performed at 3-, 6-, 12-, and 18-month. Root development was assessed using the Moorrees classification.</p> Results <p>Asymptomatic clinical progress and regular root development were observed in both treatment groups. More than 90% of the treated teeth were successfully followed up to 18 months, and root development progressed consistently according to the Moorrees classification. No statistically significant difference was found between direct pulp capping and pulpotomy in terms of clinical or radiographic success (p &gt;0.05).</p> Conclusion <p>The data obtained indicate that in immature permanent teeth with reversible pulpitis, both direct pulp capping and pulpotomy treatments can provide similar clinical, radiographic, and physiological outcomes.</p> Trial registration <p>The study was retrospectively registered in ClinicalTrials.gov (<a href="https://clinicaltrials.gov">https://clinicaltrials.gov</a>) with the registration ID NCT06575062 (2024-08-28).</p>