Method to Investigate Bioelectric Regeneration of Bone in Periodontal Defects RAYMOND A. KOPCZYK, LOUIS A. NORTON, and MARKELL W. KOHN College of Dentistry, Albert B. Chandler Medical Center, University of Kentucky, Lexington, Kentucky 40506, USA A piezoelectric potential may be generated when bone is stressed artificially or by function (FuKADA and YASUDA, J Physiol Soc Jap 12: 11581168, 1957; BASSETT, Sci Am 213: 18-25, 1965). Minute electric currents applied during bone repair and growth produce physical change (LAVINE ET AL, Science 175: 1118-1120, 1972; NORTON and MOORE, J Dent Res 51: 1492-1499, 1972). In view of these findings, it was hypothesized that new bone growth may be directed into a pathologically occurring defect by the application of current. To test this hypothesis, it was necessary to design a tissue-compatible miniature power source with low current values and long life, find a suitable experimental animal, and perfect a surgical implantation technique. A power source was designed which consisted of a 1.35 v hearing aid battery, a 1/ w 12 megolhm resistor and two dissimilar electrode wires. A direct current of 1.1 x 10-4 amperes was generated (SMITH, Ann NY Acad Sci 238: 500-507, 1974). Wire connections were made with a silver-filled epoxy compound., The power source was encapsulated with an epoxy resinb and reencapsulated in silastic elastomere (Fig 1). Adult beagle dogs with chronic periodontal disease were selected as the experimental animals. Beagles are a suitable size for surgical implantation and manifest a periodontal bone loss simSupported by a General Research Grant to the University of Kentucky and a grant from the Southern Society of Orthodontists. Received for publication June 5, 1974 Accepted for publication October 25, 1974. a Starnetics Co., North Hollywood, Calif. bStyCast #2651 and Catalyst #9, Emerson & Cuming, Inc., Northbrook, Ill. c Dow-Corning Corp., Medical Products Division,

Midland, Mich.

ilar to that seen in humans. Periodontal defects were evaluated with a Fox-Williams probe and radiographs. Interproximal and furcation bony defect areas of the mandible were used in this investigation. Each experimental defect had a similar defect on the opposite side serving as a

conitrol (unconnected circuit) . Under general anesthesia, the submandibular asea of each dog was prepared in the usual surgical manner. A submandibular incision was made andc extendedl to the inferior botder of the mandible by blunt dissection. The genierator was wired to the inferior border of the mandible an(l a subperiosteal tun-inel was madle on each sidle of the periodontal defect. The end of each electrode wire was stripped of insuilation and placed into a tutnnel (Fig 2). When required, the electrode wires were further stabilized by suturing to periosteum. The incision was closed in layers with absorbable sutures. Following initial resorption at the surgical sites, the bone was labeledl witlh an intraperitoneal injection of a vital dye' as a time zero marker. The power source ouitput was confirmed at the beginning and end of the experimental per-iod of 45 days. The generator appearedI to be compatible vith oral tissuies and remained functional tthroughout the experimental period. Implanting the generator at the inferior bor(ler of the dog's mandlible proved to be a workable method. However, because of the size of the generatoi, implantation in the area of the maxilla was, not feasible. Refinements in miniaturization of the generator design are presently being carried out to develop a workable method for implanting generators in the dog's maxilla. d Procion H-8s, Colab Laboratories, Inc., Glenwood, Ill.

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FIG 1.-Power source.

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FIG 2.-Electrode wires were placed on facial and lingual side of interproximal defect. Generator was wired to inferior border of mandible.

J Dent Res July-August 1975, Vol 54 No. 4

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