This document reviews research on analyzing the strength of helical gear teeth. It summarizes 6 research papers that used theoretical, analytical and finite element methods to calculate bending and contact stresses on helical gear teeth. The studies found that finite element analysis results aligned closely with theoretical values. Key factors analyzed included varying helix angle, face width, pressure angle and material. Increased helix angle and decreased face width were found to increase contact stress. Finite element analysis was found to provide a more accurate model than theoretical equations by considering a continuous load rather than a single point load.