Glossary

The human body possesses the incredible ability to heal itself over time. Cells, which are living units that are the foundation of the body; they renew themselves constantly and work to bring the body back to “normal,” or a state of homeostasis. They operate according to instructions found within the DNA, or the body’s unique “blueprint” for life. This includes a healing mechanism: cells that are damaged may be able to repair themselves, and cells that are destroyed are replaced. Healthy cells surrounding an injury, which is essentially a group of destroyed cells, will begin to replicate quickly. At the same time, platelets are sent to the area to stop any bleeding, and white blood cells start digesting dead cells to make room for new ones. When healing is complete, the process simply stops on its own. The body is constantly in a state of healing itself, generating new cells and replacing dead or destroyed cells.

Healing by first (primary) intention, or primary closure, refers to the healing of a wound in which the edges are closely re-approximated. In this type of wound healing, union or restoration of continuity occurs directly with minimal granulation tissue and scar formation. It works best with wounds or incisions where there has been little loss of tissue. Healing by primary intention is often used in a surgical setting where a clean incision is present. The wound is closed by using skin adhesive, staples, Steri-Strips, or sutures. This is the opposite approach to the one taken by secondary closure, or healing by second (secondary) intention, in which a gap is left between the edges of the wound for natural healing to occur. In dental applications, primary closure may be used following an oral surgery, implant, or restoration procedure where there has been little tissue loss to help prevent infection and aid in the healing process.

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.

The healing period, also known as the healing phase, is the time allocated for healing following one surgery and before the next surgery that will be performed at the same site. Dental implant preparations often require more than one procedure to achieve the final product. For example, some patients require bone augmentation procedures before an implant can be placed. The time between the bone augmentation and the implant placement is the healing period or healing phase. This phase may be necessary before subsequent procedures for several reasons including to allow for decrease in swelling and inflammation in affected tissues, to provide time for incisions to heal and for bone osseointegration, and to provide an opportunity for any complications to be addressed and resolved. The healing period allows the procedure site to be in the best possible condition for the success of implant and prosthesis placements or for other subsequent surgeries.

Heat necrosis is cell death caused by effectively prolonged exposure of bone to elevated temperature such as during an osteotomy preparation. An osteotomy is a procedure that cuts, shortens, lengthens, or otherwise reshapes a bone. In dentistry, osteotomies are required in some patients because of a condition where the bones of the face do not meet with the bite position of their teeth. In order to correct this, an osteotomy is done on the lower jaw to bring it into a correct position for proper bite alignment. Heat necrosis can occur during this type of procedure due to the friction involved in bone cutting. To avoid this type of cell death, an osteotomy may be performed using a piezoelectric device. Such devices allow for precise cutting of bone without substantial damage to the surrounding soft tissues. Piezoelectric surgical devices utilize ultrasound technology rather than traditional cutting methods to reduce cell death due to heat necrosis.

A hematoma is a localized mass of extravasated blood, usually clotted, that is relatively or completely confined within an organ or tissue. Hematomas differ from smaller bruises in that the latter occur as a result of damage or injury to small blood vessels while the former comes from damage to larger blood vessels. A hematoma can occur in dentistry following a surgery, treatment, or other oral procedure where the tissues of the mouth are manipulated in such a way that blood vessel damage can occur. Though hematomas are generally not dangerous and can be a common side effect of some dental procedures, the practitioner will often examine it to ensure it will heal without additional aid. Some patients experience a hematoma following an injection used to numb or block the sensation in the tissues around a dental procedure site. Most hematomas will resolve on their own.

Hematopoietic stem cells are the precursors of mature blood cells that are defined by their ability to replace the bone marrow system following its obliteration (e.g., by gamma-irradiation) and can continue to produce mature blood cells. Hematopoietic stem cells give rise to red blood cells, white blood cells, and platelets and can be found both in the bone marrow and in the peripheral blood. Hematopoietic stem cells are often used in stem cell transplantation to rebuild a patient’s hematopoietic system following the destruction of the system as part of a medical treatment. Stem cell transplants have been found to be an effective option for patients suffering from diseases such as lymphoma, leukemia, sickle cell disease, some genetic disorders, and some autoimmune diseases. Hematopoietic stem cells may be harvested from donor blood marrow, donor peripheral blood, or donor umbilical cord blood and then transferred to the patient via infusion methods.

Hemostasis is the arrest of bleeding either physiologically, surgically, or mechanically. Many dental procedures require the disturbance of hard and soft tissues which can lead to bleeding. Most bleeding due to these procedures is usually controlled by applying pressure to the site. However, there are times when the bleeding is more substantial or prolonged and other means of achieving hemostasis are required. Other options often include the use of sutures to close the site of the incision or electrocautery to seal the exposed blood vessels. There have also been developments in topical agents that induce hemostasis when applied to the affected area. Such hemostatic materials generally work by enhancing or speeding up the blood clotting process that takes place naturally at the site of the wound. Though these agents cannot be used alone, they may provide an additional route to achieving hemostasis following an oral surgery.