Journal of Periodontal Research 16: 358-361. 1981 Short Communicati >n

The effect of notching into dentinon new cementum formation during

periodontal wound healing

STEVE GARRETT. GARY BOGLE. DON ADAMS AND JAN EGELBERG

School of Dentistry, Loma Linda UniversityLoma Linda, California. USA

(Accepted for publication October 23. 1980)

Numerous studies involving regenerativeperiodontal therapy have noted new ce-mentum formation either heginnitig orprimarily located within a notch used todelineate the apical extent of the existingperiodontal defect (Linghorne 1957. Pat-terson. Collings & Zimmerman 1967. Mor-ris 1969, 1978, Listgarten 1972, Frank et al.1974). This phenomenon could be the resultof either (!) a stimulating effect on ce-mentum formation of the notch itself orthe exposure into the dentin created by thenotch; (2) the notch location being at ornear the base of the defect, close to theperiodontal ligament where the best poten-tial for regeneration ma\ exist. The presentstudy was designed to investigate these pos-sibilities.

The tnaxillar> cuspids in five aged beagledogs were selected for the study. Full thick-ness buccal flaps were reflected. Approx-imately 4mm of buccal marginal bone wasremoved surgically and the exposed rootsurface was carefully root planed, in acoronal-apical direction, three parallel.3mm long and 1 mm wide notches were cutin the exposed root surface of each tooth,approximately 1mm deep into the dentin.

The apical termination of the grooves waslocated 1mm from the margin of the re-duced alveolar bone. Coronally the groovesextended i-3mm from the cemento-ename!junction (Fig. I). The flaps were replacedand sutured. Post surgical plaque controlwas accompli.shed by topical application of

Fig. 1. Placement of notches into the e>;posed r::olsurface. N = notch. AB = alveola' bone, CEJ = ce-menlO'enamel junction.

N O T C H I N G I N T O D E N T I N A N D N E W 359

Fig. J. New cemenlum formation along the wall of the notch as well as the adjacent unnotched dentin sur-face. Original magnification t25 x. Inset stiowing the location of the photomicrograph in relation to thanotch NC = New cementum, CT = Connective tissue. D = Denim.

tetracyctine ointment (Aureomycin®. 3 %. weeks block biopsies were obtained. StepLederle, Pearl River, N.Y., USA) on alter- serial cross sections at 98 micron intervalsnate days. After a bealing period of 12 were cut throughout the entire verticai ex-

=IQ. 3. The base of a nolch demonstrating new cementum lormation on Ihe dentin surface. Original magnifi-cation 125 X. NC = New cementum.

360 G A R R E T T . B O G L E , A D A M S A N D E G E L B E R G

Fig. A. Epithelization of part of a notch wall. Origmal magnification 125 X.

tent of the notches and studied histolog-ically via light microscopy.

The majority of the specimens showedreattachment of connective tissue in the

full extension of the notches (Figs. 2 and 3).Some specimens demonstrated an epithelia!lining generally confined to the area ad-jacent to the cemento-enamel junction

Fig. 5. New cementum formation on old cementum and adjacenl instrumented dentinal surface in an un-notched area. Originai magnification 125 v, OC - Old cementum, NC = New cementom.

N O T C H I N G I N T O D E N T I N A N D N E W C E M E N T U M 361

(i ig. 4). In areas witb connective tissue re-attachment nev, cementum was consistentlyformed on exposed dentin in the depth ofthe notches (Fig. 3) as well as on the wallsof the notches and the adjacent unnotchedareas (Fig. 2). In unnotched areas, newcementum was also observed on old ce-mentum not completely removed with rootplaning (Fig. 5). New cementum seemed tohave formed in comparable amounts in allareas of reattachment regardless of thepresence or absence of notches.

Within the parameters of this study.notches seem to have no effect on the rateor quantity of new cementum formation.The notches were deliberately placed in apreviously uninvolved area of the root sur-face, exposed surgically, to help assure newcementum formation during healing. TheTact that the notches failed to acceleratecementum formation in this model raisessome doubt on the ability of notches per seto stimulate cementogenesis. The locationof the notches near the apicai extent of thelesions, and close to the periodontal liga-ment, may explain the predeliction of newcementum formation in the notches ofprevious studies.

References

Frank. R.. Fiore-Donno. G.. Cimasoni. G. &Matter. J. 1974, Ultraslructural study ofepithelial and connective gingival reattach-ment in man. Journal of Periodontologv 45"626-635.

Linghome. W. J. 1957. Studies in the reattach-ment and regeneration of the supportingstructures of the teeth. IV. Regeneration incpithelized pockets following the organizationof a blood clot. Journal of Dental Re.\earch36: 4-12.

Listgarten. M. A. 1972. Electron microscopicstudy of the junction between .surgicallydenuded root surfaces and regenerated perio-dontal tissues. Journal of Periodonta! Re-.search 7: 68-90.

Morris. M. L. 1969. Periodontal healing inman. New York State Dental Journal 35-333-340.

Morris. M. L- 1978. The effects of root shapeand biology on bone growth. Journal ofPeriodontology 49: 33-36.

Patterson. R. L.. Collings, C. K. & Zimmer-man, E. R, 1967. Autogenous implants in thealveolar process of the dog with inducedperiodontitis. Periodontics 5: 19-25.

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