Dental Retention grooves for class 3 restoration are placed: A Bucco axial and linguo axial line angles. B Occlusoaxial line angles. C Axiogingival line angle. D Retention grooves are not possible in class 3 preparation. 💡 Explanation Retention grooves for class 3 restoration are placed: ✓ Correct Answer: C. Axiogingival line angle.