Forensic odontology plays a significant role in human identification. Forensic odontology through dental identification will be crucial when fingerprinting is invalid due to the disintegrated body as teeth usually are the last part of the body that remains when the body is decomposed or burned. One of the ways for human identification is through age estimation. There are various methods to estimate age through the dental aspect. However, the radiological method has received attention for its non-destructive method. Age estimation in children can be done by seeing its dentition period. However, adult age estimation has been a challenge. Secondary dentin deposition and pulp reduction throughout age were stated to have the ability to estimate adult age. This review compares the Kvaal method and Cameriere method in adult age estimation, which assess the pulp reduction due to the secondary dentin deposition through the dental radiological method. Data searches were conducted through four databases, including PubMed, Scopus, EBSCO, and Scielo, following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA). Differences between Kvaal and Cameriere original method include the radiograph used, tooth used, measurement tools, and measurement variables used. Most studies showed that the periapical radiograph gave more accurate results compared to the panoramic in both methods. Moreover, most studies showed no significant difference between gender and diverse results between age groups in both methods. The population used in the study, methodology, observers' reliability in the measurement, and the secondary dentin pattern affect the result and reliability of both methods.