failure of the technique of producing the specimens. The authors feel that if the surface microporosity could be overcome the implants should perform adequately. G. A. Smith
MORRIS M. L. The effects of root shape and biology on bone growth, J. Periodontol. 49 (1978) 33-35. An experiment was undertaken in which roots of teeth were implanted together with fresh autogenous haemopoietic marrow into the abdominal subcutaneous tissue of ZOO+ white female Sherman strain rats. Two implants were inserted in each of 12 animals which were sacrificed at 1, 2, 3, 4 and 6 weeks and 2, 3, 4, 6 and 8 months. The roots had been treated in different ways so that a comparison could be made between healthy roots which had been nicked, pre-heated njcked diseased roots, pre-heated nicked healthy roots, diseased nicked roots, decalcified nicked healthy roots, healthy flat roots, diseased flat roots and decalcified nicked diseased roots. It was found that making a nick in the roots had a significant effect in promoting osseous growth, but that this effect was neutralized when the roots had been previously decalcified and were diseased. An osseous regeneration was also less favouratle in the case of the flat-rooted teeth and it appeared, therefore, that nicking had some effect on promoting osseous growth. A. Bryan Wade
ORALMEDICINEANDPATHOLOGY RUPRECHT A. and MANG Rapid internal resorption, (1978) 239-240.
B. L. Dent. Abstr.
23
A series of radiographs taken for other purposes revealed the process of rapid internal resorption of an upper central incisor. Within a period of 6 weeks an area of minimal internal resorption progressed so rapidly as to render treatment virtually impossible. Andrew Richardson
ROBINSON M. and ARNET G. Use of cobalt radiation to prevent reankylosis, Dent. Abstr. 23 (1978) 259-260. As a result of an automobile accident and subsequent surgery, a patient suffered ankyfosis of both temporomandibular joints. Over the next 10 years the patient underwent eight surgical procedures for treatment of ankylosis. At the end of this time the patient could achieve only a 6-mm opening of the jaws. The right side of the mandible was continuous with the zygomatic arch, mandibular fossa and articular tubercle. There was an attached mass of bone in the infratemporal fossa. Similar conditions were found on the left side except that there was no bony mass. The patient then received ten cobalt radiation treatments totalling 2000 rad during a 2-week period. During subsequent months the patient gained an opening of 28 mm. When seen 3 years after the cobalt irradiation he could open 25.5 mm in the midline. Andrew Richardson
PERIODONTOLOG
Y
WAERHAUG J. Healing of the dento-epithelial junction following subgingival plaque control. 1. As observed in human biopsy material, J. Periodontol. 49 (1978) l-8. An experiment was undertaken in 21 individuals in whom subgingival calculus and plaque were assiduously removed, and subsequently at intervals varying from 2 weeks to 7 months the gingival tissue was removed by making a horizontal incision 2-3 mm below the alveolar crest and vertical incisions into the interdental papilla on either side. The alveolar crest with the tooth was then cut through with a thin fissure burr so that the tissue could be removed. It was admitted that the soft tissue wall of the pocket was moved in relation to the tooth and in many cases reflected as much as 45’ in relation to the hard tissue wall of the pocket, but the soft tissue was pressed back into position and it was considered that