The management of cervical composite restorations, also known as Class V restorations, represents a challenge in contemporary dentistry. This difficulty arises from the complex nature of cervical lesions and unfavorable location, close to soft tissues prone biofilm accumulation. Additionally, cervical composite restorations have significant failure rates, further complicating their management and longevity. The etiological factors contributing to cervical cavitation are diverse, ranging from mechanical trauma, abrasion, and erosion leading to non-carious cervical lesions (NCCLs), to cariogenic biofilms responsible for root caries. The combination of these factors, high failure rates, varied etiology, and the technical difficulty of restoring dentin-margin cavities underscores the need for advanced understanding of proper management and techniques in treating cervical composite restorations. This master thesis is presented in chapters with the following aims: 1) perform a scoping review as a preliminary assessment to identify how restorative protocols (surface pre-treatment, such as etching with different agents and techniques, like bevel) influence the longevity outcome of non-carious cervical lesions (NCCLs) restorations, and, 2) to comprehensively analyze and compare the biofilm composition grown over healthy and cavitated root caries lesions in two distinct age groups: patients younger than 65 years old (healthy and cavitated) and those older than 65 years old (healthy and cavitated). As the methodology approached, the scooping review and clinical studies were performed according to the cited objectives. For the results, a collective of the literature showed that the most frequently dentin pretreatment method studied was 'Application mode - Etching', with over 35% of studies focusing on this area, followed by 'Application mode - Adhesive' in 34% of the studies. 'Pre-treatment of surface with substance' was the focus of around 14% 'Pre-treatment of surface with lasers' accounted for approximately 11% of studies (Chapter 1.) In our clinical study the analysis of predominant bacteria in control and cavitated root caries lesions across two age groups (<65 years old and >65 years old) reveals notable variations in microbial composition. Cavitated lesions exhibit higher bacterial diversity compared to control ones, as indicated by the Shannon diversity index, suggesting a more complex microbial ecosystem within these lesions. Furthermore, the Simpson's dominance index suggests that control lesions are characterized by a few dominating species, contrasting with the more evenly distributed bacterial community in cavitated lesions. Age-related differences further modify these patterns, with older individuals displaying distinct bacterial profiles. These findings underscore the impact of lesion type and patient age on the oral microbiota's diversity and dominance, highlighting the complexity of microbial ecosystems in root caries lesions. (chapter 2)