The present study was undertaken to determine the effect of four periodontal regenerative procedures on the connective tissue attachment level. The procedures tested were: 1) the modified Widman flap procedure, 2) the modified Widman flap procedure combined with transplantation of previously frozen autogenous red marrow and cancellous bone, 3) the modified Widman flap procedure in combination with implantation of beta tricalcium phosphate, and 4) periodic root planing and soft tissue curettage. Eight adult Rhesus monkeys, divided into four equal groups, were used. Periodontal pockets were produced around contralateral teeth in a standardized manner. In each group of animals, the pockets on one side of the jaws were subjected to one of the above-mentioned surgical treatments, while the contralateral pockets remained as unoperated controls. Three weeks before surgery, a carefully designed plaque control program was instituted and continued until the animals were sacrificed 12 months after surgery. In histologic sections, linear measurements along the root surfaces were made from the cemento-enamel junction (CEJ) to the most apical cells of the junctional epithelium (JE). These measurements from operated and unoperated sites were then compared. The data revealed that healing following the four different regenerative procedures resulted in the reformation of an epithelial lining (long junctional epithelium) along the treated root surfaces, with no new connective tissue attachment.

The purpose of this investigation was to determine histologically the depth of probe tip penetration into the clinically healthy gingival sulcus of humans using a controlled inserton pressure of 25 g. The midfacial gingival units of 22 maxillary and mandibular incisor, canine and premolar teeth, displaying no visual signs of inflammation, were used for probing determinations. An electronic pressure-sensitive probe, with a terminal probe tip diameter of 0.35 mm, was used to standardize insertion pressures. After insertion of the probe into the sulcus, it was then aligned on the facial surface of the gingiva with the tip corresponding to the depth and location of probe insertion. A horizontal reference incision was made on the facial gingival surface which corresponded to the depth of the sulcus probed. This incision served as a histologic landmark of probe tip generation. Gingival biopsies were taken, and step-serial sections analyzed histologically and histometrically. Probe tip penetration was coronal to the apical end of the junctional epithelium in all cases (mean = 0.25 mm). In addition, probe tip penetration was always apical to the coronal end of the junctional epithelium (mean = 0.70 mm).

Utilizing a nonhuman primate model, a study was carried out to determine the nature of the attachment between the tooth and the gingival tissues following periodic root planing and soft tissue curettage. Under the conditions of this investigation, periodic root planing and soft tissue curettage combined with thrice weekly plaque control resulted in the formation of a long junctional epithelium with no new connective tissue attachment. In eight of the 22 experimental pockets, however, this procedure produced discontinuities or "windows" in the junctional epithelium. The coronal attachment of gingival tissues to the root surface (increased resistance to probing) commonly reported following root planing and soft tissue curettage appears to result from the formation of a long junctional epithelium rather than new connective tissue attachment.

This report describes the osseous repair of an infrabony pocket without new attachment of connective tissue between the new bone and root surface. While the width of the connective tissue between the new bone and root surface was of approximately normal dimensions, junctional epithelium was present on the root surface.

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