Complex sentence: Each tuft consists of several unconnected leaves that start near the dentineenamel junction and as they pass through the enamel rods to the surface they become progressively more fragmented and fibrillar.
Split into simpler sentences: Each tuft consists of several unconnected leaves that start near the dentineenamel junction. These defects as they pass through the enamel rods to the surface they become progressively more fragmented and fibrillar.