The cumulative loss of mineralized tissues due to physical or physicochemical processes results in tooth surface wear. (Schlueter et al., 2020) With the maintenance of teeth for a longer time, and with their dietary, parafunctional, and hygiene habits, dental wear becomes more frequent in the elderly. (Grippo et al., 2012, Smith and Knight, 1984) Noncarious cervical lesions (NCCL) are the loss of tooth structure near the cervical region without the involvement of microorganisms. (Levitch et al., 1994) NCCL occur close to the cementoenamel junction given the characteristics of the cervical region, such as a thin layer of enamel and irregular structure of the prisms, the concentration of nonaxial occlusal forces, and the high susceptibility to acid dissolution in the transition between dentin and enamel. (Borcic et al., 2004, Kolak et al., 2018) The etiology of NCCL is multifactorial, including abrasive, erosive, and tensional mechanisms, often combined. (Grippo et al., 2012, Grippo et al., 2004) The role of each etiologic factor is still a subject of discussion in the literature.

Saliva is in direct contact with the tooth surface and seems to play a relevant role in the development of NCCL. (Grippo et al., 2012, Souza et al., 2017) The occurrence of NCCL seems to happen more frequently in sites relatively unprotected by saliva. (Young & Khan, 2002) Salivary fluid, through its flow, its buffering capacity, and its pH, performs important functions, such as dilution and maintenance of oral acidity by neutralizing intrinsic and extrinsic acids. (Dawes et al., 2015, Lynge Pedersen and Belstrøm, 2019) Altered salivary parameters could contribute to the development of NCCL, potentially influencing the dentin chemical degradation. (Souza et al., 2017)

The average prevalence of NCCL is considered high in the population, ranging from 9.1% to 93%, according to a recent systematic review. (Teixeira et al., 2020) These data reinforce the need for studies that seek to understand the mechanisms involved in the development of NCCL and to improve early diagnosis and treatment practices. As saliva is simple to collect and obtain, its analysis becomes increasingly relevant in dental practice. However, evidence in the scientific literature of the association between salivary characteristics and the occurrence of NCCL is scarce. Thus, this study aimed to carry out a systematic review of the evidence contained in observational studies researching the association between salivary factors (quantity and quality of saliva) and NCCL in individuals with permanent dentition.