Morphometry of Rabbit anatomical regions used as experimental models in implantology and oral surgery. Eduardo Borie 1* , Ricardo Calzzani 2 , Fernando José Dias 1 , Ramon Fuentes 1 , Carlos Salamanca 3 1 Research Centre in Dental Sciences (CICO), Dental School, Universidad de La Frontera, Temuco, Chile 2 Ribeirao Preto Dental School, University of São Paulo, Ribeirao Preto, SP, Brazil 3 Universidad Adventista de Chile, Chillan, Chile Abstract The animal model has been widely used in the biomaterials field. However, there are no morphometric patterns to create critical size defects in different areas used in implantology and oral surgery, based on the anatomy and histology of the rabbit’s tissue. Thus, the aim of this study is to provide measurements and limits for future research on the different anatomical regions used to evaluate biomaterials and/or surgical procedures in rabbits as animal models. Twenty-two rabbit heads were used in the study. The soft tissue was removed and the calvaria, body of the mandible divided into three regions, the ramus of the mandible, total mandible length and lower cortical sinus thickness were measured. The mean, standard deviation and confidence of each region were recorded. The height of the mandibular ramus was 30.1 mm and 29.7 mm for the right and left sides, respectively, while the total body of mandible was 67.2 mm. Also, the thickness of calvaria and lower cortical sinus were 1.5 mm and 1.1 mm, respectively. In conclusion, the limited dimensions of anatomical structures should be considered when working with critical size defects in rabbits to avoid complications or accidents during the specimen’s surgery. Keywords: Rabbit, Morphometry, Anatomy, Implantology, Oral surgery. Accepted on April 28, 2017 Introduction The development of bioactive materials for tissue engineering has increased considerably for use on in vitro and in vivo models [1]. Accordingly, the animal model has been widely used in the study of biomaterials, placed in critical size defects, to analyse their influence [2]. The literature shows the use of dog [3,4], rat [5] and rabbit models [6], among others, to study bone healing. Among the different animal models, one of the most frequently used is the rabbit due to low cost, easy manipulation, high bone metabolism and quick craniofacial development [7]. Research focused on bone healing in rabbits was conducted in different regions of the mandible [8] and calvaria [9]. However, the anatomy and size of each region of rabbit skull and mandible may influence the number of critical size defects. The applied anatomy enables the clinician to identify details of relevant structures intraoperatively [10]. In this context, a study by Valdivia et al. [11] reported some measurements of rabbit mandible after transection of inferior alveolar nerves in growing rabbits. Despite the large amount of information available in the literature, there are no morphometric patterns to create critical size defects in different areas used in implantology and oral surgery based on the anatomy and histology of the rabbit’s tissue that would enable exact repeatability of methodologies and rendering more reliable results. Therefore, this study aims to provide measurements and limits for future research on the different anatomical regions used to evaluate biomaterials and/or surgical procedures using rabbits as animal models. Material and Methods The following study was approved by the Ethics Committee of the Faculty of Ribeirao Preto Dental School, University of São Paulo (Protocol 055/2012). Twenty-two rabbit heads discarded from other research that were not included or have not caused metabolic bone diseases were used to conduct the study. The samples, which included male and female specimens, were treated previously by enucleating the eyes and removing the skin and most of the muscles. After this, the samples were immersed in hot hydrogen peroxide (130 vol, Mazzochini, Caxias do Sul, Brazil) at 80ºC for 2 h and maintained at 37ºC for 48 h to remove the remnants of organic tissue. Subsequently, the samples were washed with distilled water and dried. ISSN 0970-938X www.biomedres.info Biomed Res- India 2017 Volume 28 Issue 12 Biomedical Research 2017; 28 (12): 5468-5472 5468