Joichiro Hayashi

Probucol Downregulates E-Selectin Expression on Cultured Human Vascular Endothelial Cells

Probucol, which inhibits monocyte adhesion, is a potent antioxidant to vascular endothelium in the cholesterol-fed rabbit. The accumulation of macrophages in the lesion is influenced by increased expression of specific adhesion molecules on vascular endothelial cells. We investigated the effect of probucol on the expression of cell adhesion molecules in cultured human umbilical vein endothelial cells (HUVECs). HUVECs were treated with lipopolysaccharide in the presence or absence of probucol (0 to 5 mumol/L) and assayed for the expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and E-selectin by cell-enzyme-linked immunosorbent assay. Probucol significantly downregulated the expression of E-selectin on HUVECs in a dose-dependent manner. In contrast, the expression of ICAM-1 was not affected. E-selectin but not ICAM-1 mRNA expression on HUVECs was also significantly inhibited by probucol in a dose-dependent manner. We also examined whether probucol affects cellular binding between the human monocytic cell line U937 and lipopolysaccharide-stimulated HUVECs by using an in vitro binding assay and found that probucol significantly suppressed their mutual binding in a dose-dependent manner. These data indicate a novel mechanism of action for probucol to reduce the development of atherosclerotic lesions in hyperlipidemic states.

Minimally Invasive Surgical Approaches for Esthetic Implant Dentistry: A Case Report

A lthough replacing missing single teeth with dental implants has become routine, restoring anterior teeth with implant-supported crowns is highly techniquesensitive and remains a challenging task. The longterm clinical and esthetic success of an implant-supported restoration is determined by stable peri-implant soft-tissue morphology that is in harmony with the surrounding tissue architecture of the natural dentition. However, after secondstage dental implant surgery, peri-implant soft tissues recede approximately 0.8 to 1.4 mm. Recession usually occurs during the first 3 to 6 months after surgery. As a result, correction of marginal soft tissue morphology around implant restoration is required in some cases. Subepithelial connective tissue graft techniques are a predictable means to treat gingival recession in natural dentition and to correct peri-implant soft tissue margins, offering a good color match with the adjacent tissues. However, this technique has some disadvantages, such as increased technical difficulty and the involvement of two surgical areas, one being the palatal wound donor area. The semilunar coronally positioned flap (SCPF) had been described to cover denuded root surfaces. This technique causes no disturbance of the adjacent papillae, no shortening of the vestibule, and no tension on the flap. In addition to these advantages, no sutures are needed. Therefore, it is a minimally invasive periodontal plastic surgery to treat gingival recession. Several clinical trials confirmed the predictability of this technique when used to treat Miller Class I gingival recession defects. Nevertheless, to our knowledge, no study or case report has described resolution of recession around implant restorations using this technique. In some cases of esthetic implant restoration, the correction of gingival margin of natural teeth adjacent to implants could be a better solution for esthetic problems than that of marginal soft tissue around implant. Surgical crown-lengthening procedures, such as apically positioned flap with osseous resection, are often performed to adjust gingival levels for an esthetic outcome. However, the rate of gingival growth after surgery differs in the facial and interdental areas, causing changes in crown form, and the position of the free gingival margin changes during healing periods ranging from 3 to 12 months. In addition, attachment loss occurs at adjacent teeth. Thus, it is difficult to control the final gingival margin and determine the correct timing of subgingival crown placement, especially in esthetic areas. In this case report, we describe two surgical approaches to harmonize peri-implant soft-tissue morphology with the surrounding tissue architecture of the natural dentition based on the philosophy of minimally invasive dentistry. One surgical approach is SCPF to coronally position the marginal soft tissue around the implant restoration; the other is a flapless technique to lengthen a crown, namely, minimally invasive esthetic crown lengthening (MIECL) to achieve the desired free gingival margin position in a short period.