Effects of autoclaving on compressive strength of bovine bones and their use as chewing agents for dogs

This study aimed to evaluate the effect of autoclave processing on compressive stress of spongy and cortical bones, and the effect of autoclaved bones as chewing agents to reduce dental calculus in adult dogs. Spongy and cortical bones were autoclaved (1 ATM, 30 min, and 120°C) and compressive strength was evaluated in autoclaved and raw bone specimens. Autoclaved bones were offered to ten Beagle dogs divided into two groups of 5 dogs each: Group 1 – received a portion of the autoclaved bovine cortical bone (ACB) and Group 2 – received a portion of the autoclaved bovine spongy bone (ASB). Prior to the experimental period (1-d) and every two days thereafter, oral photographs were taken on both sides of the dental arch to evaluate dental calculus reduction over time. The vestibular surface of the canines, premolars, and molars teeth was evaluated using integration software to measure the proportion between the area covered by calculus and the total teeth area. The effect of bone type, treatment (raw vs. autoclaved), and their interaction were evaluated using the PROC GLIMMIX procedure of SAS (version 9.4). Linear equations were generated to estimate calculus reduction over time for ACB and ASB. Compressive strength was higher (P < 0.05) in cortical bones compared to spongy bones. However, the autoclaving procedure did not affect (P > 0.05) compressive strength, regardless of the bone type. The teeth area covered by calculus of dogs that were offered ACB reduced from 41% to 32% in 5 days, and at the end of 15 days a reduction of 62.2% was observed, resulting in a remaining of 15.5% of teeth area covered by calculus. In this group, the dental calculus area reduced by 57.7% after 5 days, and at the end of the trial, only 5.4% of teeth were still covered by calculus, which represents a reduction of 81%. The linear regression analysis revealed no significant difference between the slopes for the ACB and ASB equations (P > 0.05). No health complications such as tooth fracture, intestinal obstructions, and oral lesions were observed throughout the study. Our results demonstrated that the autoclave processing did not impair compressive strength of spongy and cortical bones. This corroborates with the results observed in vivo, which suggests that autoclaved bones are chewing agents for adult dogs with additional benefits of lower risk of bacterial contamination.