Etty Tagger

Release of Calcium and Hydroxyl Ions from Set Endodontic Sealers Containing Calcium Hydroxide

Endodontic sealers that contain calcium hydroxide are claimed to possess calcification-promoting properties. Similar liners and hard-setting bases exhibit great variations in their alkalinizing potential and this property has been correlated with their biological effect. The purpose of this study was to investigate the release of calcium and hydroxyl ions from three root canal sealers by extraction with water. Calcium was assessed by EGTA titration and hydroxyl ions by measuring pH. The pattern of release of ions differed in all three sealers. In Sealapex it was similar to that of the control bases, Dycal and Life. Another sealer, Hermetic, rapidly dumped the extractable calcium hydroxide, while release of calcium from CRCS was negligible. The alkalinizing potential was more durable in all three. Disintegration of the pellets of Sealapex indicated that solubility may be the price for increased activity.

Subcutaneous reactions to implantation of tubes with AH26 and Grossman's sealer

Twenty-seven polyethylene tubes filled with either U of P brand of Grossmans sealer or silver-free AH26 (Dentinol) were implanted in the backs of seven young guinea pigs. Tissue reactions were studied histologically after 2 months and graded for inflammation and thickness of capsule. The surface of AH26 that was slightly convex or flush with the opening of the tube had a significantly thinner capsule than U of P. The latter also caused more inflammation. The more severe subcutaneous tissue reaction to the zinc oxide--eugenol type of sealer was probably due to the instability of the material, which slowly disintegrated in contact with tissue moisture. This process continuously liberated new foreign particles and prevented resolution of inflammation.

Pulp capping in monkeys with Reolit and Life, two calcium hydroxide bases with different pH

Hart-setting calcium hydroxide-containing bases are expected to promote formation of a calcified bridge when applied to an exposed pulp. However, upon setting, the pH of the base, unlike that of a paste, may quickly drop and the release of calcium ions also may be short-lived. Since formation of a bridge seems to depend upon the pH, two commercially available bases were compared: Life (Sybron) that has a pH of 10 to 11 at setting and Reolit (Vivadent) that has an almost neutral pH. Fifteen sound molar and premolar teeth of two young vervet monkeys were exposed under rubber dam and capped with either material. The set base was protected with amalgam. The animals were killed 10 wk later and the jaws were separated into blocks for histological processing. Dentinal bridges were observed in most of the Life specimens. The use of Reolit resulted in incomplete bridging, pulpal inflammation, and spread of the material into the pulp, sometimes accompanied by irregular calcifications. Failure of Reolit to induce briding may be due to the difference in pH, but since the products differ in their composition, the results may be due to irritation by some of the components. The findings of this investigation indicate that Reolit should not be used for direct pulp capping.

Pulpal and periapical reactions to glutaraldehyde and paraformaldehyde pulpotomy dressing in monkeys

Pulpotomies were performed in 23 young posterior teeth of two vervet monkeys. Two dressings were compared: glutaraldehyde in ZOE paste and paraformaldehyde in the same vehicle and ZOE alone served as control. The teeth and their surrounding structures were examined histologically after 3 and 9 months. Paraformaldehyde induced total pulpal necrosis and chronic apical inflammation. In all glutaraldehyde-treated teeth, the pulp remained mostly vital and there was no periapical reaction. Calcifications in the pulp cavity were evident. The vehicle alone, ZOE, also permitted the pulp to remain vital, exhibiting calcifications but no full bridges. None of the experimental specimens showed complete pulpal healing; however, in contrast to paraformaldehyde-treated teeth, glutaraldehyde-treated ones retained their vitality and produced no apical involvement.

Effect of the endodontic status of the tooth on experimental periodontal reattachment in baboons: A preliminary investigation

The effect of the endodontic status of the tooth on periodontal reattachment after the raising of a mucogingival flap was studied with the use of 48 teeth in four old baboons. Root canal therapy was performed on 26 front teeth. Tubliseal, AH26, N2, and Diaket were used as sealers with gutta-percha. The pulps of 5 teeth were exposed and left infected; 17 teeth with intact pulps served as a control. The teeth and their surrounding structures were studied histologically for reattachment with new cementum formation 2 to 17 days, 1 to 2 months, and up to 1 year after the operation. In the teeth examined 1 month postoperatively or more, if epithelium had not covered the denuded surface, new cementum was present, regardless of the endodontic status.

Periodontal ligament injection: spread of the solution in the dog.

Investigations of the spread of anesthetic solutions administered with the periodontal ligament injection have reported conflicting findings. The purpose of this investigation was to study the distribution of the injected fluid by macroscopic and microscopic techniques. One third of the liquid of the carpules (2% lidocaine with 1:100,000 epinephrine) was replaced with India ink as a marker. Injections were made with a pressure syringe, (Ligmaject) at 90 sites in 12 dogs. Twenty-five control sites were injected with a marked solution without a vasoconstrictor (3% mepivacaine). Seven dogs were killed within 24 h; the others after 5 days. Spread of the ink was studied in undemineralized slices, in three-dimensional cleared specimens, and in histological sections. The solution usually reached the alveolar crest, seeped under the periosteum, and entered into bone marrow spaces alongside vascular channels. The ink spread along the path of least resistance, influenced by the intricacies of anatomical structures and fascial planes, rather than penetrating into the periodontal ligament or in the root canal. In the controls without a vasoconstrictor the spread was more diffuse. Five days postoperatively, carbon particles were present only within macrophages.

Pulpal reactions to a dentin bonding agent: Dentin adhesit*

Pulpal reactions to a dentin bonding agent, Dentin Adhesit, were studied in 27 teeth of two monkeys. The investigation was carried out as a “usage test” in freshly prepared cervical cavities in conjunction with a composite resin (Heliosit). Life was used as a control liner. At the intermediate period (35 days), the teeth exhibited a subodontoblastic inflammatory reaction and little apposition of new dentin. The long-term specimens (74 days) showed recovery of the pulp, with minimal inflammation present in only a few teeth, and reparative dentin formation under practically all experimental and control cavities.

Histological study of untreated pulps in hemisected teeth in baboons

Human pulps extirpated 2 wk after exposure by root resection, but without treatment, showed few inflammatory changes. The purpose of the present study was to replicate and supplement a previous human study by examining the tissue within the root canals. Eight roots of hemisected mandibular premolars and molars of an adult baboon were extracted for histological examination to 4 wk after the procedure. Additional roots were left in situ for 6 months and radiographs showed lesions of varying sizes at their apices. At 1 wk, the pulp was vital with a narrow hemorrhagic zone and a few neutrophils. Odontoblasts were missing after 2 wk. The pulp was still vital in the apical part of the canal at 3 wk but it was necrotic at 4 wk with debris and microorganisms present in the pulp chamber.