The effect of topically applied citric acid on periodontally diseased root surfaces was evaluated using the scanning (SEM) and transmission (TEM) electron microscopes. Results with the SEM indicate that acid application had no effect on specimens that had not been root planed. After application to root planed surfaces, however, the acid priduced a fiber‐like surface with frequent depressions. TEM observations showed that the acid application produced a four micron wide demineralized zone, which was characterized by exposed collagen fibrils. These fibrils seemed to be continuous between the mineralized and demineralized zones of the root. It appears that the relative success of the citric acid application in periodontal reattachment procedures is realted to the fact that the acid causes exposure of collagen fibrils in the dentin matrix, thus providing a suitable nidus for splicing with new fibrils during the healing process.

This study was designed to histologically determine the relationship of the periodontal probe tip to the periodontal tissues during probing of untreated periodontal pockets and periodontal pockets treated with oral hygiene and root planing. Human, condemned, single rooted teeth with buccal probing pocket depth at least 6 mm were used. Two groups of specimens were included: 12 untreated teeth from six patients and 15 treated teeth from 10 patients. In the treated group, the effects of therapy were monitored clinically every 2 weeks until maximum improvement had taken place. A periodontal probe tip was then inserted on the buccal aspect of the tooth using 0.50 N pressure, and block section biopsies were taken. The histologic examination of the untreated teeth showed that the probe tip penetrated beyond the apical termination of the junctional epithelium and into the subjacent connective tissue by a mean of 0.45 +/- 0.34 mm, whereas in the treated specimens the probe stopped coronally to this landmark by a mean of 0.73 +/- 0.80 mm. This study demonstrated that the probe tip most often does not reach the base of the junctional epithelium in pockets treated by plaque control and root planing, and that clinical measurements of attachment levels are not reliable in determining the true histologic level of connective tissue attachment.

Recognition of patients who are likely to experience pain during periodontal treatment can be facilitated by the use of 2 questions on dental anxiety and the VAS response to probing during examination.

Sixteen dental, dental hygiene, and dental assisting students and dental faculty members who had contralateral or unilateral areas of minimal (less than or equal to 1.0 mm) and appreciable (greater than or equal to 2.0 mm) widths of keratinized gingiva on mid-buccal plaque-free surfaces of mandibular bicuspids were examined. Gingival exudate amounts and clinical inflammation based on color change and/or swelling and bleeding on probing were evaluated. The results showed that gingiva with "appreciable" width as well as gingiva with "minimal" width of keratinized tissue exhibited only minute amounts of gingival exudate. Also, there were generally no clinical signs of inflammation for both types of tissue. From the groups of 16, six subjects were selected who had contralateral pairs of minimal and appreciable keratinized gingiva. They were instructed to cease oral hygiene in the lower bicuspid area for 25 days. At day 0, 4, 7, 11, 14, 18, 21, and 25, plaque, gingival exudate, and clinical gingival inflammation were evaluated. Results revealed increases in plaque, gingival exudate scores and clinical gingival inflammation over the 25-day period with no apparent difference between the areas with minimal and appreciable width of keratinized gingiva.

A study was made to investigate the biological principle of new attachment of connective tissue to periodontally diseased root surfaces utilizing the previous finding that topical application of citric acid to the affected area may stimulate periodontal regeneration. Reconstructive surgery was performed on ten surfaces of nine teeth involved in advanced chronic periodontal disease. A muco‐periosteal flap was raised and the apical extent of existing subgingival calculus was demarcated by a notch made through the calculus and into the root. Following thorough instrumentation, a saturated solution of citric acid was applied to the root surface for five minutes and the flap repositioned and sutured. Four months later the teeth with attached periodontal tissues were removed and processed for histological analysis. Connective tissue regeneration characterized by deposition of new cementum, and more coronally, by tightly apposed soft connective tissue had occurred in all specimens. The junctional epithelium ended 1.2–2.6 mm coronal to the apical border of the notch in the various specimens. The results demonstrate that regeneration of periodontal tissues to a root surface that has become denuded as a result of chronic, destructive periodontal disease and that has been covered by calculus is, in fact, a biological possibility. This study does not establish whether or not acid conditioning of the root surface is a prerequisite for new attachment.