Immunohistochemical, histomorphometric and microtomographic comparative study between autogenous bone and xenogenic bone in onlay graft surgery in rabbit mandibles

Author(s)

Erick Ricardo Silva

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2019-09-27

Examining board members

Samuel Porfirio Xavier; Antonio Carlos Pereira Gomes; Walter Martins Junior; Michel Reis Messora

• Advisor: Samuel Porfirio Xavier

Abstract

The search for bone substitutes as an alternative to autogenous bone has increased in recent years. Xenogenous bone blocks are considered an option for horizontal reconstruction of atrophic alveolar ridges. The aim of this study was to compare, by means of histomorphometry, immunohistochemistry and microtomography, graft incorporation and remodeling processes of autogenous and equine xenogenous (Heket Biomaterials, Trento, Italy) bone blocks used for mandibular lateral augmentation in rabbits. Eighteen New Zealand male rabbits, with 3.5 - 4.0 kg of weight and 4 - 5 months of age, were included in this split-mouth randomized study. The lateral side of the angle of the mandible was augmented bilaterally with either block autografts or xenografts. Animals were euthanized after 7, 20 and 60 days of healing, respectively. Biopsies were taken for each period and specimens underwent microtomographic scanning. Total graft volume (TV, mm3) and bone volume (BV: residual graft plus new bone, mm3) were measured for both autogenous and xenogenous groups using CTAn software (Bruker, Kontich, Belgium). Paraffin sections were prepared and stained in hematoxylin and eosin and Masson´s trichrome. For histomorphometric evaluation, a grid consisting of 80 squares was superposed to the image of histological slides for counting the structures at a magnification of ×200. The percentages of residual graft and new bone were assessed. The graft incorporation and remodeling molecular events were evaluated by means of VEGF, Col I, OPN, ALP, OC and Casp 3 immunolabelling. ANOVA and the Student\'s t test were performed. Both autogenous and xenogenous bone blocks presented similar percentages of newly formed bone over time. However, the volume and the quality of the grafted area was superior at the autogenous compared to the equine xenogenous graft group. (AU)

• FAPESP's process: 17/02116-7 - Immunohistochemical, histomorphometric and microtomographic comparative study between autogenous bone and xenogenic bone in onlay graft surgery in rabbit mandibles
• Grantee: Erick Ricardo Silva
• Support Opportunities: Scholarships in Brazil - Doctorate