Viability of Bovine Teeth as a Substrate in Bond Strength Tests: A Systematic Review and Meta-analysis.

PURPOSE: To assess whether bovine teeth can be used as viable alternatives for human teeth in tensile and shear bond strength testing.

MATERIALS AND METHODS: Articles were selected from Web of Science, PubMed, Scopus, LILACS-Bireme, and BBO electronic databases using keywords obtained from Medical Subject Headings (MeSH). Of 1540 potentially eligible studies, 157 were selected for full text analysis. Five independent reviewers (Kappa = 0.89) selected the studies, abstracted information, and assessed quality based on standardized scales. After the analysis, 78 studies comparing bovine teeth to human teeth were found. Only 18 studies comparing bovine and human substrates in bond strength tests were included in the systematic review and 13 in the meta-analysis. Two authors independently selected the studies, extracted the data and assessed the risk of bias. Mean differences were obtained by comparing tensile and shear bond strengths between human and bovine teeth (permanent and deciduous) and considering enamel and dentin separately (subgroup analysis). Statistical analysis was performed using RevMan5.1, with a random-effect model, at a 5% significance level.

RESULTS: No significant difference was found between human and bovine teeth in tensile tests (p = 0.41) for dentin (p = 0.86), but there was a difference for enamel (p = 0.01). Regarding shear bond strength, no significant difference was found between human and bovine teeth (p = 0.16) either for enamel (p = 0.07) or dentin (p = 0.68). Regarding shear bond strength on deciduous teeth, no significant difference was found between human and bovine substrates (p = 0.54), either for enamel (p = 0.42) or dentin (p = 0.05). Most studies were at high (low or unclear) risk of bias.

CONCLUSIONS: In shear bond strength testing, bovine teeth can be a suitable alternative for permanent and deciduous human teeth, for both enamel and dentin substrates. However, they may not be suitable for enamel tensile bond strength testing. The findings are based on low quality studies (considerable heterogeneity) and should be interpreted with caution.