The Posterior Bolton Discrepancy, a mismatch in tooth size between upper and lower posterior teeth, can hinder proper occlusion during orthodontic treatment. This review examines how malocclusion type, premolar extraction patterns, gender, and ethnicity influence posterior Bolton ratios, based on studies published between 1990 and 2025. Findings show that discrepancies are more pronounced in Class II malocclusions, significantly affected by extraction patterns, and vary across populations, making Bolton’s original norms less universally applicable. Recent evidence, especially between 2017 and 2025, suggests that posterior The type of malocclusion, sex, race, and extraction technique all have a major impact on TSD. Notably, Class II malocclusions display lower posterior ratios while Class III shows higher ratios; both observations underscore the importance of thoughtful treatment strategy in these populations. Methods and tools such as digital Bolton calculators or region-specific algorithms like the Johnson–Bailey prediction method improve accuracy over traditional Bolton calculations.
