Types of External Root Resorption of Replanted Teeth: Analysis of the Clinical Aspects and of Interleukin-4 Gene Polymorphisms Involvement Liliane Roskamp, DDS, MSc, PhD, Paula Cristina Trevilatto, DDS, MSc, PhD, Cleber Machado Souza, DDS, MSc, PhD, Ulisses Xavier Silva Neto, DDS, MSc, PhD, Everdan Carneiro, DDS, MSc, PhD, Luiz Fernando Fariniuk, DDS, MSc, PhD, and V^ ania Portela Ditzel Westphalen, DDS, MSc, PhD Abstract Introduction: The absence or presence of root resorp- tion on the surface of a replanted tooth indicates an immune-inflammatory reaction. Recent research even suggests the participation of host predominant immuno- logic profile on types of resorptions detected on the root surface. Because interleukin 4 (IL-4) is an important anti- inflammatory cytokine, this study aimed to investigate the association of clinical variables and polymorphisms in IL4 with types of resorption of replanted teeth after 1 year of follow-up. Methods: One hundred twenty- seven avulsed teeth that were replanted were selected. Periapical radiographs were taken after replantation and for 1 year to detect the types of root resorption. Real-time polymerase chain reaction was used to geno- type IL4 polymorphisms. The c 2 and Z tests were per- formed to verify the association of clinical and genetic variables with the outcomes of replanted teeth (P < .05). Results: An association was observed of extra-alveolar time, storage medium, and development of the root (P < .05), but not of IL4 polymorphisms, with the outcomes of replanted teeth (P > .05). Conclu- sions: Extraoral time, storage medium, and develop- ment of the root, but not IL4 polymorphisms, may influence the types of resorption of avulsed and re- planted teeth in the first year after trauma. (J Endod 2017;-:1–5) Key Words Avulsion, cytokines, inflammation, polymorphisms, replantation, root resorption D ental avulsion is a very serious trauma, and the most appropriate approach is dental replan- tation (1). However, root resorption presents a major challenge. It mainly occurs on total or partial loss of the periodontal ligament, compromising the cementoblast layer in addition to the immune- inflammatory response of the patient (2, 3). It can result in tooth loss, compromising the patient aesthetically, functionally, and psychologically. Clinical aspects of replantation, such as the extra-alveolar time of the avulsed tooth, time elapsed between trauma and first treatment, storage medium before dental replantation, intracanal medication, intensity of the inflammatory reaction triggered by the avulsion, and the presence of bacteria in the socket, will determine the impact on the root surface (1). Thus, the predominantly immune-inflammatory host response may have a fundamental importance in the maintenance of tissue health or disease. In pre- vious studies, it was demonstrated that an atopic patient who has a predominantly T-helper 2 (Th2) immunologic profile, which means responds predominantly with anti-inflammatory cytokines such as interleukin 4 (IL-4), had a better outcome 1 year after replantation (3–5). This condition may also create an advantage in losing fewer teeth because of replacement resorption after 5 years of follow-up (6). Because cytokines are encoded by DNA and regulate the immune response, it is important to analyze the genetic characteristics of the patients to determine their contri- bution to the development of root resorption. Single nucleotide polymorphisms (SNPs) are the most common forms of variation in DNA. They may affect the quantity or function of the expressed protein, resulting in changes in both innate and adaptive immune re- sponses, by determining the susceptibility or protection to a given disease (7). For this reason, this study focused on the polymorphic variations of IL4 gene (8), in high linkage disequilibrium (LD), to genotype all the ‘‘target’’ SNPs (tag SNP), an approach that cap- tures all the variability information in IL4 gene (9). Therefore, this research aimed to verify a possible association of tag SNPs in IL4 and clinical characteristics with the types of external root resorption of replanted teeth in 1 year of follow-up. From the School of Life Sciences, Pontif  ıcia Universidade Cat olica do Paran a, Curitiba, Brazil. Address requests for reprints to Dr Liliane Roskamp, Department of Endodontics, School of Life Sciences, Pontif  ıcia Universidade Cat olica do Paran a (PUCPR), R. Imaculada Conceic ¸ ~ ao, 1155, Prado Velho, Curitiba, PR, Brazil 80242980. E-mail address: lroskamp@gmail.com 0099-2399/$ - see front matter Copyright ª 2017 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2017.06.027 Significance This is the first study in literature demonstrating the influence of the management of avulsed teeth and IL4 polymorphisms on different types of root resorption in replanted teeth. It may contribute to research molecular biomarkers and supporting materials and techniques for preventing resorption. Clinical Research JOE — Volume -, Number -, - 2017 Management of Replantation and IL4 Polymorphisms on Different Types of Root Resorption 1