The purpose of this study was to characterize, using the scanning electron microscope, the nature of root surfaces denuded by (1) root planing alone or (2) root planing plus citric acid treatment. Six teeth were extracted from three squirrel monkeys, and the coronal half of the root surface was planed to remove attached periodontal ligament fibers and cementum. Citric acid, pH 1, was topically applied to the denuded surfaces of 3 teeth. The surface of only root-planed specimens had an irregular surface which corresponded to a smear layer. Root surfaces that had received acid treatment after root planing exhibited funnel-shaped orifices of dentinal tubules, and intertubular zones with a fibrillar, mat-like morphology. The implications of the different root-surface characteristics are discussed.

This report describes the initial in vivo wound healing response of connective tissue components and cells to demineralized and nondemineralized dentin surfaces. Rectangular dentin specimens were prepared from beneath root surfaces covered by periodontal ligament. One group of six specimens were treated with citric acid, while another six specimens served as untreated controls. Specimens were implanted vertically into the skin of rats such that one end of the implant protruded above the skin. After one day, the implants were removed, and the dentin surface‐connective tissue interface was examined using scanning electron microscopic methods. The surface of the nondemineralized dentin implants had the morphological characteristics of a surface smear layer. Cells that were present on these nondemineralized surfaces were rounded in shape with few processes or extensions to the dentin surface or to other cells. The surfaces of the demineralized dentin implants were fibrillar in appearance and were usually covered by a layer that had many globular and fibrillar structures attached. Cells that were present on these demineralized surfaces exhibited marked bipolarity with distinct attachments to the dentin surface. Cell processes often extended into the openings of demineralized dentin tubules. It was concluded that an established cellular and connective tissue response to demineralized dentin occurred within the first 24 hours of wound healing, and that this response differed markedly from that associated with nondemineralized dentin surfaces.

Alterations in rat myometrial ultrastructure and in vitro uterine contractile responses to oxytocin were examined in estradiol-treated (40 pg/kg) euglycemic and streptozotocin-induced (85 mglkg) diabetic rats. Myometrial morphology was examined 18, 24, and 36 hr after estradiol administration. At the time points examined, nuclei of myometrial cells from euglycemic and diabetic rats were pleomorphic and contained large areas of heterochromatin dispersed throughout the nuclei. Mitochondria were round to oval in shape and contained a dense matrix with cristae that extended across the mitochondria. Myofilaments were found in both euglycemic and diabetic cells but the relative number of myofilaments in diabetic cells appeared to be less than the number found in myometrial cells removed from euglycemic animals. The number of free cytoplasmic ribosomes in diabetic cells also appeared to be less than those found in euglycemic cells. In order to determine if apparent differences in the number of myofilament found in diabetic myometrial cells could be correlated with changes in uterine contractile responses to hormones, oxytocin dose-response curves (lop8 to M ) were examined in isolated uteri removed from salineinjected and estradiol-injected (24-hr pretreatments) euglycemic and diabetic rats. The maximal contractile responses (milligrams tension developed per milligrams tissue) in saline-injected eu-

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Alterations in endometrial cell morphology following oestradiol treatment of ovariectomized animals were examined in euglycaemic and streptozotocin-induced diabetic rats. Endometrial morphology was exa-