Samuel Seltzer

Flare-ups in endodontics: I. Etiological factors

A number of hypothetical mechanisms which may be responsible for pain and swelling before and during endodontic therapy are presented. These mechanisms may be interrelated.

Periodontal Effects of Root Perforations Before and During Endodontic Procedures

Periodontal tissue reactions to root perforations in the teeth of dogs and humans have been studied by Euler,l KUbler,2 Ruchenstein,3 Kaufmann,4 Taatz and Stiefel,5 and Lantz and Persson.6,7 In general, inflammatory reactions were more severe when the perforated regions were left open to saliva or when the entrance regions were closed with zinc phosphate cement. Reactions were less severe when the perforation canals were sealed with gutta-percha immediately after the perforations were made or soon thereafter. In a clinical and histologic investigation of endodontically treated teeth that had failed, Seltzer et a18 found that some of them had perforations of the floor of the pulp chamber, presumably made by improper access openings. Should such perforations occur without the operators knowledge, the failures of endodontically treated teeth might be attributed unjustly to some other factors. Therefore, knowing the outcome of endodontically treated teeth with perforated roots should contribute to an informed prognosis for such teeth. During endodontic experiments on monkeys,9-11 a number of teeth were accidentally perforated before or during treatment.

The effect of periodontal disease on the pulp

Abstract A new syndrome, the pulpodontic-periodontic syndrome, is defined. This clinical entity can be of pulpal and periodontal origin with an aggregation of pulpal and periodontal symptoms. A proper sequence of therapy is suggested, based on differential diagnosis as to whether endodontic or periodontic treatment should be instituted first.

Microbiologic factors in endodontology

The role of microorganisms in the cause of endodontic lesions has been intensively investigated. Bacterial components such as endotoxin and other cell wall components are implicated in the development of pulpal and periapical inflammation. Newer anaerobic microbiologic techniques have facilitated accurate and reproducible identification of endodontic pathogens, some of which have been reclassified. This article reviews and correlates newer microbiologic findings with clinical symptoms.

Alteration of human pain thresholds by nutritional manipulation and L-tryptophan supplementation.

Abstract Pain perception and tolerance thresholds of 30 normal subjects were determined by electrical stimulation of dental pulps before and after dietary manipulation which included either tryptophan supplementation or placebo. Perception threshold levels were similar in tryptophan and placebo subjects; however, pain tolerance levels were significantly higher in the group receiving tryptophan. Side effects such as nausea, skin itching, weight loss and mood elevation were more common in the tryptophan group than in the placebo group.

A scanning electron microscope examination of silver cones removed from endodontically treated teeth

Abstract Twenty-five silver cones were removed from teeth which had been treated endodontically from 3 months to 20 years previously. Examination by the scanning electron microscope revealed that these cones were moderately to severely corroded. The corrosion patterns were described as ranging from pitting to deep crater formation with globular or spherical agglomerations. Examinations with the electron probe showed sulfur peaks on the corroded portions of the cones. X-ray diffraction analyses indicated that the chemical compounds formed were silver sulfides, silver sulfates, silver carbonates, and silver amine sulfate amide hydrates. Tissue culture studies indicated that the corrosion products were highly cytotoxic. The mechanisms for the formation of the corrosion products have been postulated as being due to plastic deformations and metal transfer to the silver cones, plus contact of the silver with tissue fluids.

Biologic aspects of endodontics. IV. Periapical tissue reactions to root-filled teeth whose canals had been instrumented short of their apices.

Pulp extirpations and root canal instrumentation shy of the apices of the teeth were performed on thirty-four human anterior teeth and on thirty-two roots of sixteen teeth of Macaca rhesus monkeys. The root canals were then filled short of the apices of twenty-four human teeth and twenty-two roots of eleven monkey teeth. Root canal fillings were purposely forced beyond the apices of nine human teeth and ten roots of five animal teeth. Observations were made of the periapical tissue reactions to those procedures after time intervals ranging from 6 to 270 days in the human groups and 14 days to 270 days in the animal series. Comparisons were made between the periapical tissue reactions of the two groups. Periapical tissue reactions were similar in both groups, initially. There was an acute inflammatory response in the apical pulp and periapical tissues, which was gradually superseded by chronic inflammation. Dentine filings were found to have been impacted on the remaining apical pulp stump in the group in which the canals had been filled shy of the apex. When the filling material had been pushed beyond the apex, the dentine debris and root canal filling materials were found in the periapical tissues. In both groups, periapical inflammation was accompanied by root end and alveolar bone resorption. Within 3 to 6 months, repair of the resorptions by secondary cementum and bone elaboration occurred routinely in most of the teeth. From 6 to 12 months later such repair was generally complete in the group in which the canals were filled shy of the apices. Repair was delayed in the group in which the canals had been overfilled. In addition, in this group there was a greater tendency toward proliferation of cell rests of Malassez. Foreign filling material in the periapical tissues tended to become encapsulated by collagen fibers. It was concluded that, in cases of vital pulp extirpation, optimum results, in terms of tissue repair, were obtained when root canals were instrumented and filled short of the apices of the teeth.

Biologic aspects of endodontics: V. Periapical tissue reactions to root canal instrumentation beyond the apex and root canal fillings short of and beyond the apex

Abstract The defense resources of the periapical tissues are apparently capable of overcoming the effects of instrumentation, but cements and root canal filling materials in the periapical tissues cause persistence of inflammation.

Epithelial proliferation in periapical lesions

Abstract Various endodontic procedures were performed on seventy-two teeth which had no periapical pathosis prior to endodontic treatment. From 6 to 360 days later the periapical tissues of these teeth were examined histologically. In eighteen such tissues (26 per cent), proliferation of cell rests of Malassez had occurred. The lowest incidence of epithelial growth appeared in cases in which the root canals had been instrumented short of the root apices of the teeth and then left unfilled (25 per cent) or filled short of the apices (17 per cent). The highest incidence of epithelial proliferation appeared in those cases in which the root canals were instrumented and filled beyond the apices of the teeth (46 per cent). Epithelium began to proliferate as early as 14 days after endodontic treatment. In six of fourteen lesions, there was evidence of entrapment and degeneration of epithelial strands in newly formed collagen fibers. Twenty-two teeth in which periapical lesions were present prior to endodontic therapy were examined histologically. In five of these teeth no endodontic therapy had been undertaken, and in seventeen teeth endodontic therapy had been performed 10 to 220 days prior to root resection. Epithelial proliferation was found in ten of the twenty-two lesions. Studies of the epithelium in seven specimens 56 to 220 days after endodontic therapy had been performed revealed that the epithelium was degenerating in three lesions. In four lesions no degenerative epithelium changes could be discerned.

Classification of pulpal pathosis

Abstract Clinical evidence which indicates the presence of severe pulpal pathosis dictates a treatment policy of pulp extirpation and endodontic therapy. In the absence of such evidence, therapeutic management by indirect pulp capping is the preferable regimen. In such cases, efforts should be made to maintain pulp vitality, even though chronic pulp inflammation may persist. The vitality of the pulp should be maintained as long as possible in the absence of evidence that chronic pulp inflammation is harmful to the well-being of the organism. The defensive capacity of the pulp is thereby retained.