fa عمومى General پژوهشي Research <strong>Introduction: </strong>Traumatic injuries or caries to developing permanent teeth may prevent the integrity of root maturation and finally result in pulp necrosis, vital pulp therapy (VPT) is a suitable treatment for these teeth.&nbsp; This article describes a successful apexogenesis report of a nine year old boy with impact trauma to the mandibular left first molar which caused complicated crown fracture, pulp exposure and thereupon spontaneous pain.<br> <strong>Methods</strong>: Cervical pulpotomy was performed and the remaining pulp was capped with mineral trioxide aggregate (MTA). Afterwards the crown was restored using a stainless steel crown, the patient was followed up using radiographic images and clinical examinations 6 and 12 months after the treatment.<br> <strong>Findings</strong>: The follow up documents indicated that the tooth maturation was completed, the apex was developed and a calcified barrier was formed right above the remaining vital pulp and no other endodontic treatments were needed.<br> <strong>Conclusion</strong>: Regarding to the excellent healing potential of the immature vital pulp and using MTA as medicated filling matter, clinical and radiographic documents represent MTA as a successful pulpotomy agent in immature permanent teeth. Apexogenesis, Mineral Trioxide Aggregate, Open apex, Pulpotomy, Trauma 68 72 http://intjmi.com/browse.php?a_code=A-10-1-234&slc_lang=fa&sid=1 Ali Malekzadeh Shafaroudi 10031947532846002137 10031947532846002137 No Student research committee, Faculty of Dentistry, Mazandaran University of Medical Sciences, Sari, Iran. Haleh Hali 10031947532846002138 10031947532846002138 Yes Assistant Professor, Department of pedodontics, Dental Faculty, Mazandaran University of Medical Sciences, Sari, Iran.