b. Granulation. The process of healing involves the invasion and replacement
of dying and dead tissue by immature mesenchyma called granulation tissue.
Granulation tissue consists mostly of fibroblasts and capillaries. As wound repair
progresses, the fibrous and vascular cell components gradually convert into a mature
tissue. Then, old epithelial cells at the wound edge proliferate to cover the new fibrous
tissue surface. If the wound edges are not brought together or are exposed to irritants
or infections, granulation tissue forms on the opposing surfaces and fills the space.
c. First Intention. This is the healing process observed when the wound
surfaces are close together, such as in a small cut or in a closely sutured wound. The
first step in repair is the formation of a clot. This clot is slowly replaced by granulation
tissue and a covering of epithelium. When the edges of a clean aseptic wound are
closely approximated, rapidly growing (proliferative) connective tissue cells join the
walls of the wound and proliferative epithelial cells close over the surface. In first
intention, the wound heals without scarring.
d. Second Intention. This is the healing process observed when the opposing
edges of the wound are not together, such as in a large ulcer. Granulation tissue fills in
the wound from the base and eventually is covered with epithelium. In many instances,
repair results in less than completely normal regeneration, causing altered tissue
structure that forms a fibrous scar. In second intention, healing is often characterized
by the formation of a scar.
Section II. EROSION, ABRASION, AND RESORPTION
There are conditions (besides dental caries) in which there is loss of tooth
substance. They are erosion, abrasion and attrition, and resorption.
Erosion is the chemical wearing away of the tooth structure by a chemical
process that does not involve bacterial function. A common cause of erosion is chronic
vomiting which results in enamel destruction through the action on teeth by stomach
acids. Excess use of acidic carbonated beverages or acid citrus fruits may also be
causative factors. Erosion is usually found on the external surface of the tooth on
enamel structure adjacent to the cemento-enamel junction. It appears as various
shapes cut into the surface at the neck of the tooth. The enamel and dentin are usually
hard and shiny. In certain cases, the crowns may be severed from the roots.
Considerable variation in appearance is normal between cases, but generally several
teeth are involved, usually on the outer (labial) aspect of the crown.