ORIGINAL ARTICLE Comparative study in photodynamic therapy using the same photosensitizer in tissue repair after second-degree burns in an experimental model Kesia Maria Mangoni Gonçalves dos Santos 1 & Maria Elvira Ribeiro Cordeiro 1 & Mário César da Silva Pereira 2 & Danillo Barbosa 3 & André Alexandre Pezzini 4 & Ivo Ilvan Kerppers 2 Received: 21 August 2019 /Accepted: 24 November 2019 # Springer Nature Switzerland AG 2019 Abstract Introduction Photodynamic therapy is a therapeutic resource used to treat different pathologies such as neoplasias and wound healing. It consists of a light coupled to a photosensitizer that is used to react with oxygen and forming reactive oxygen species that reach target cells. Objective This study aimed to evaluate the effect of PDT on the healing of second-degree burns. Methods The study used 45 Wistar Rattus Norvegicus divided into three groups, two with lesions and treatment and one with lesions and without treatment (control group). Group PDT6 was lesioned and treated with 630- nm LED PDT and group PDT9 was lesioned and treated with 945- nm LED PDT. Results The results suggest collagen deposition and development of cellular structures of normal tissue in the treated groups compared to the control groups. Conclusion It was concluded that the PDT treatment induced enhanced tissue repair in the treated groups; the best results were observed using the 630- nm LED. Keywords LED . Photodynamic therapy . Burn . Healing . Phototherapy . Tissue remodeling . Tissue lesion Introduction The skin is considered the largest organ in the human body with various functions attributed to it. Burns are among the most frequent causes of damage to this organ leading to malfunction and even loss of function. The classification of burns is based on the depth of the in- jured skin. These lesions are called superficial (first degree) of a partial thickness (second degree) or total thickness (third de- gree). First-degree burns only compromise the epidermis, are hyperemic painful, and present edema. Second-degree burns may be superficial, damaging the dermis and its upper layer, * Ivo Ilvan Kerppers ikerppers@gmail.com Kesia Maria Mangoni Gonçalves dos Santos Kesia.maria@hotmail.com Maria Elvira Ribeiro Cordeiro mariaelvirar.99@gmail.com Mário César da Silva Pereira mcpereira@unicentro.br Danillo Barbosa danillo.barbosa@hotmail.com André Alexandre Pezzini www.pezzini@hotmail.com 1 Pharmacy School, Universidade Estadual do Centro-Oeste, Guarapuava, PR, Brazil 2 Laboratory of Neuroanatomy and Neurophysiology, Universidade Estadual do Centro-Oeste, Rua Simeão Camargo Varela de Sá, 03, Guarapuava, PR 85040-180, Brazil 3 Department of Physical Therapy, Functional Neurology Discipline, Universidade Estadual do Centro-Oeste, Guarapuava, PR, Brazil 4 Master’ s Degree Program in Dentistry, Universidade Estadual do Centro-Oeste, Cascavel, PR, Brazil Lasers in Dental Science https://doi.org/10.1007/s41547-019-00081-8