E F F E C T OF CHLORTETRACYCLINE MOUTHRINSES ON THE HEALING OF RECURRENT APTHOUS ULCERS: A DOUBLEBLIND CONTROLLED TRIAL Guggenheimer, J., Brightman, V. J. and Ship, 1.1. J. Oral Ther. 4:406408, March, 1968 Seven patients with severe recurrent apthous ulcers were used as subjects for an eightmonth test period. Ulcer activity was expressed as total number of ulcers, total new ulcers and total ulcer days, and duration of ulcers in terms of the number of days for healing. Chlortetracycline hydrochloride, 50 mg. water soluble tablets or placebos of similar color, taste and solubility were given to each patient for one week's use as a mouthwash, four times a day. The time required for ulcers to heal was re duced 40 to 50% compared to when no treatment was given or when a placebo was given. No significant differences in total ulcer days, total ulcers or total new ulcers was observed. Side effects of the Chlortetracycline mouthwash were common and included allergic reactions, bad taste, burning and soreness of throat, and angular cheilosis. Careful consideration must be given before this form of treatment is prescribed. Department of Dentistry and General Clinical Research Center, Philadelphia General Hospital, Philadelphia, Pennsylvania. C E L L CONTACTS IN ORAL EPITHELIA Thilander, H . and Bloom, G. D . J. Periodont. Res. 3:96110, #2, 1968 Twelve adults (ages 1740) were utilized as sources of biop sies of normal, noninflamed buccal gingiva, palatal gingiva, retromolar and upper vestibular mucosa to study desmosomes, tight junctions, and intermediate junctions by electron micros copy. It was found that the desmosomes maintained their ap pearance in all layers except in the highly keratinized specimens where they appeared as a threelayered structure between the thickened cell membranes in the stratum corneum. Tight junc tions in the basal layer and stratum spinosum were classified as maculae occludentes and this term was defined to mean fusion of adjoining cell membranes in very small areas or spots. In the stratum granulosum and corneum these tight junctions were called zonulae occludentes because they represented belts of membrane fusion. The intermediate junctions were numerous and of different lengths and appeared to be the principal mode of attachment of clear cells to adjoining epithelial cells. The dif ference between the basement membrane and tissue surface ap peared to be the closure of intercellular spaces by tight junctions or modified desmosomes. Permeability conditions in the epithe lium are discussed. Departments of Oral Surgery and Histology, University of Umea, Sweden. ACRYLATEAMIDE SPONGE FOR REPAIR OF ALVEOLAR BONE DEFECTS Henefer, E . P., McFall, T. A. and Hauschild, D . C. J. Oral Surg. 26:577581, September, 1968 Acrylateamide sponge was incorporated into 20 squirrel mon keys at the area between maxillary laterals and canines where flaps and osseous defects were made with rotating burs bilater ally. One side was treated with the sponge while the other re mained as the control. The animals were sacrificed at intervals from two months to one year and specimens prepared for histo logical examination. Findings demonstrated the grafted area to have superior bony and overlying soft tissue contour as com pared to concave contouring in control sites. There was delay in bone regeneration in the graft sites, with the earliest formation at two months. The synthetic graft became well vascularized and fibrous connective tissue grew into the spaces of the sponge. There was no evidence of carcinogenesis or active rejection in any of the experimental specimens. Department of Oral Surgery and Anesthesia, School of Dental Medicine, University of Penn sylvania, Philadelphia, Pennsylvania.