Healing by second intention, also known as secondary closure, is the healing of a wound in which a gap is left between its edges. Union occurs by granulation tissue formation from the base and the sides. This requires epithelial migration, collagen deposition, contraction, and remodeling during healing. Healing by second or secondary intention differs from healing by first or primary intention in that it does not bring the edges of the wound or incision into contact with each other. Healing by first intention is best used in situations where there is a clean incision with little tissue loss while healing by second intention may take place when there is not enough tissue to bring the edges of the wound together for suturing or stapling. Secondary closure is considered the most important type of bone healing in procedures that include maxillo-facial surgeries. It occurs through cell proliferation which eventually becomes lamellar bone.