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.
Histomorphometry is the quantitative study of the microscopic organization and structure of a tissue, such as bone. The term especially applies to a study conducted by computer-assisted analysis of images acquired from a microscope. Histomorphometric studies are of special importance in determining changes that take place in the bones or teeth following bone grafting and implant procedures. The microscopic images allow for a detailed analysis of changes to the surface of the tissue, implant, or prosthesis as well as changes in their underlying structures. The information gained from such analyses can then be used to create more reliable and longer-lasting implants, to determine which type of microtexture is more successful for bone-to-bone contact, and how texture of the implant surface affects the osteoconductive capacity. Though implants and prostheses can be evaluated on a larger mechanical level, the use of histomorphometry provides insight into what is happening on the microscopic and cellular levels.
A hollow basket implant, also called a hollow cylinder implant system, was created in the late 1970s at the Straumann Institute in Waldenberg, Switzerland. Its design differs greatly from a traditional screw implant in that the implant hardware is not solid but rather crafted to be hollow, with small holes or perforations throughout the implant. The hollow basket implant design allows for almost double the contact with bone compared to a solid cylinder implant, minimizing bone destruction and promoting the fusion of bone to implant, also known as osseointegration. The design also minimizes stress to the implant when during vertical loading. The perforations in the cylinder allow for bone to grow through the implant and fill the hollow spaces, versus simply adhering to the outside of a textured solid implant screw. This provides added stability and permanency. Typically, hollow basket implants are created with a commercially pure titanium metal or titanium alloy to promote osseointegration.
The basic definition of a host response is the reaction of living tissue to the presence of a foreign material. In the broadest sense, the term “host response” can be used to describe any bodily response to an injury, surgical procedure, or implant. Within the field of dental implantology, the term host response is used to indicate the response of the patient’s bone and soft tissue to a dental implant. Ideally, the host response will be a positive one and the bone will begin to fuse to the implant, also known as osseointegration. The implant will remain stable with minimal swelling and no infection. However, in some cases, the host response is less desirable and results in implant failure. Osseointegration may not occur, the implant hardware may be rejected, or an infection may develop. Thoroughly evaluating a patient and selecting the right hardware and procedure for their needs can help ensure a positive host response.