Effects of air polishing on the resin composite-dentin interface.

The aim of this study was to examine defect depths and volumes at the resin composite-dentin (R/D) interface after air polishing with different particles and spray angles. Samples were 54 dentin specimens that were formed in saucer-shaped cavities filled with resin composite. Each specimen was air polished with either sodium bicarbonate (NaHCO3) or one of two glycine (Gly) powders. The air polisher was set at angles of 90° to the interface and at 45° to the interface from both the dentin and resin composite sides. Air polishing with Gly powder produced defects with less depth and volume than NaHCO3 powder (p < 0.05). Air polishing with a spray angle of 45° to the interface from the resin composite side produced fewer defects (p < 0.05) than polishing from the dentin side. Air polishing to the R/D interface from the resin composite side produced fewer defects to the interface because the hardness of the resin composite was higher than that of dentin.

A case of recovery of oral function with dental implants following facial bone trauma.

A 44-year-old woman had sustained facial lacerations, loss of several teeth, alveolar bone fracture, and severe vertical bone resorption in conjunction with a shattered alveolar bone and marked loss of intraoral function and facial disfigurement in a car accident. She underwent 9 surgical procedures by plastic surgeons to treat the facial lesions, including hold facial scar formation reduction surgery, reduction of fractures of the nasal and cheek bones, and bone transplants. To restore intraoral function and improve facial appearance, plastic surgeons transplanted a rib into the maxillary sinus while dental surgeons simultaneously inserted 5 dental implants. Eleven months after the dental implant surgery, a complete upper denture and a mandibular gingival ceramometal-casting crown were fitted. After insertion of the final prosthodontics, regular follow-up examinations were performed to check dental occlusion, oral hygiene, and the condition of the gingival tissue. In the years since the upper dental implants were fitted, there have been no bone resorption and no functional problems. Transplantation of rib bones is an effective method for maxillary reconstruction and remains effective even after the insertion of dental implants. The patient is extremely satisfied with the results. A means of maintaining oral health over the long term, and of motivating the patient to maintain oral health, should be established.

Effects of application of platelet releasate in periodontal regeneration therapy.

The alpha granules of platelets contain various growth factors, which display in vitro and in vivo activities known to be important in wound healing. Biologically active proteins from platelets include platelet-derived growth factor, transforming growth factor-beta, and insulin-like growth factor, as well as other less well-described angiogenic and differentiated protein factors. The purpose of this study was to evaluate histologically and histometrically the new tissue formation on furcation treatment with platelet-derived factor releasate (PR) in beagle dogs. Class II furcations were created in the mandibular premolars of eight adult male beagle dogs. Periodontal regenerative treatments were then performed using collagen sponge graft material with and without the topical application of PR. PR was prepared fresh from blood drawn from dogs before treatments. A histologic evaluation of the effect on new tissue formation was then performed by comparing periodontal tissue regeneration of sites treated with and without PR. Four and 12 weeks after the flap operations, histologic sections were processed and histologically analyzed. The evaluated parameters were bone, cementum and connective tissue attachment regeneration, length of epithelium, resorption, and ankylosis. Histologically evaluated, the regeneration of new cementum was greater at the collagen sponge with PR sites compared to the control sites throughout the entire research period (P < .01). Four and 12 weeks after the flap operations, the amount of new bone in the sites treated with PR was greater than that in the control group (P < .05). These results suggest that collagen sponge graft material with PR promotes new attachment on the periodontal tissue regeneration treatments.

Proliferation and tube formation of periodontal endothelial cells.

Angiogenesis is indispensable to guide a regeneration of good periodontal tissue in the wound healing after periodontal surgery. Hepatocyte growth factor is well known for a strong angiogenic factor and it may play important roles in the periodontal tissue during periodontal wound healing. In exploring the promotion of angiogenesis in the periodontal ligament, proliferative and tubulogenic responses of endothelial cells to hepatocyte growth factor and to soluble factors secreted by fibroblasts were investigated. Pavement-shaped cells isolated from a human periodontal ligament were identified as the endothelial cell by their granular immunoreactivity for factor VIII. The proliferation of the endothelial cells was accelerated by the addition of hepatocyte growth factor or fibroblast-conditioned medium, and far more by adding both than either. The endothelial cells seeded on the agar containing both hepatocyte growth factor and fibroblast products formed a dense network in a shorter time than on the agar containing either. The endothelial cells in the dense network took a tube-like structure with lumen and were covered with laminin. These results suggest that hepatocyte growth factor administered into the regenerating periodontal tissue may promote, synergistically with local factors produced by the activated fibroblast, the proliferation and tubulogenesis of the remaining endothelial cells.