• Journal of Periodontal and Implant Science
• /
• v.27 no.3
• /
• pp.603-619
• /
• 1997

The use of laser in the treatment of soft tissue minimizes hemorrhage, provides better view of the operating field, and thereby minimizes operating time. Also, there will be far less post-operative swelling, pain and scar formation, and sterilizing effect are shown in some portions of the wound site. All these advantages of laser therapy contribute to its widespread use in the field of medicine and dentistry. Regarding such facts, we used CO2 laser of different watts in gingivectomy for white rats to compare initial healing process. For the control group, the least amount of output in performing gingivectomy(4watts) was offered, and for the experimental group, 6watts was given. Animals were sacrificed on the second, third days, 1 weeks, 2 weeks, and 3 weeks after operation, and their specimens were histologically analyzed. The following results were obtained: 1. Blood clot of small size was observed in both the control and experimental groups after two days, and no more thereafter. 2. In both the control and experimental groups, the inflammation zone size was the greatest after two days, and it decreased gradually to become almost invisble by the second week. The experimental group showed larger size of inflammation zone during second and third days: however, there was no difference after one week. 3. Granulation tissue in both the control and experimental groups showed gradual maturation with time, and by the second week, it was almost replaced by normal connective tissue. By the third week, complete healing pattern was observed. The experimental group showed larger granulation tissue than the control group until the third day, but there was no significant difference after one week. 4. In both the control and experimental groups, gingival epithelialization began on the second day. After one week, regeneration of rete peg and partial formation of junctional epithelium were observed: by the second week, keratinization of oral sulcular epithelium began, and it was completed by the third week.

• Applied Microscopy
• /
• v.29 no.1
• /
• pp.83-94
• /
• 1999

The ultrastructure of small arterioles and capillaries in the lumbrical muscles of rat digits were studied by electron microscopy and following results were obtained. 1. The diameter of small arterioles of rat digits were $12\sim20{\mu}m$, and it was relatively smaller than human $(30\sim35{\mu}m)$. 2. All the endothelial cells of small arterioles and capillaries in the lumbrical muscles of rat digits were continuous type, and they had typical morphological characteristics of continuous endothelial cells : numerous cytoplasmic pinocytic vesicles and many tight junctions between the endothelial cells. 3. In the small arterioles subendothelial layers were irregularly spaced beneath the basal lamina, and membrane to membrane contacts were found between the endothelial cells and smooth muscle cells. 4. Pericytes were often found nearby capillary endothelium, and their cytoplasmic processes surrounded part of endothelial cells. They were enclosed by basal lamina. 5. Smooth muscle cells in tunica media of small arterioles were only one layered, that is, they were terminal arterioles. Sarcoplasm of smooth muscle cell was divided to 2 areas; homogeneous or filamentous area and non-homogeneous perinuclear area. 6. The tunica adventitia contained fibroblasts with extremely attenuated cytoplasmic processes and collagen fibirls.