INBDE (Integrated National Board Dental Examination) 2026 – 400 Free Practice Questions to Pass the Exam

Cleft lip occurs during weeks 4-5 in utero, where the facial tissues begin to form. During this stage, the tissues do not fuse together properly, resulting in the opening or separation in the upper lip. The other options provided (A, C, D) are incorrect because they are either too early or too late in the development of the facial structures to result in a cleft lip. It is important to note that the exact timing and cause of cleft lip is still being studied and understood by medical professionals.