Preclinical Rat Models in Oral Implant Dentistry: A Scoping Review of Study Design and Experimental Practices

Background: Despite the widespread clinical use of dental implants, research in implant dentistry remains active, aiming to develop new materials, designs, and surface morphologies, as well as to better understand the biological mechanisms underlying the pathophysiology of certain diseases to improve patient outcomes. In this context, preclinical animal models provide an essential opportunity to explore and validate new technologies and protocols before their application in humans. Although large vertebrate species have historically been preferred due to their biological similarity to humans, small animal models such as rats offer significant advantages. Additionally, they allow researchers to work with larger sample sizes, improving the statistical power of experimental outcomes. This scoping review aimed to analyze the current literature on intraoral rat surgical models in the field of implant dentistry. Methods: We included the preclinical studies using rat models focused on implant placement in the oral cavity and published in English. We excluded all studies that involved animal models other than rats or used implant placements in anatomical sites different from the target region. An electronic search was conducted in the PubMed and Scopus databases. From an initial 1032 results, 680 articles remained after duplicate removal. A first screening retained 191 articles, and after full-text review, 98 studies were ultimately included. The selection process was conducted using the software Rayyan. Data were extracted and analyzed across nine domains: Publication metadata, Focused Research Questions, Animal specificities, Study Design, Surgical Protocol Features, Medications Administered to Establish the Experimental Model, Timing of Euthanasia, Characterization methods, and Drop-Out Information. Results: The evaluation of the selected literature revealed a lack of standardization in study design. There is no consensus regarding the rat species used, the age at the time of implant placement, the anatomical site, or the implant morphology. Even more concerning is the presence of methodological deficiencies in the reporting of study design and outcome measures. Conclusions: By summarizing the available data, this review proposes the most commonly used features across preclinical trials in rats. Moreover, it offers a comprehensive overview of the current scientific landscape in this field, enabling researchers to compare different study designs and more easily access relevant information.