Glossary

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.