Jorge Erausquin

Root canal fillings with zinc oxide-eugenol cement in the rat molar

Abstract The histologic response of periapical tissues to root canal fillings with zinc oxide-eugenol cement was studied in the lower molars of rats. Root canal fillings were placed in normal teeth of 141 Wistar rats, and the animals were killed at different postoperative periods ranging from 24 hours to 90 days. Semiserial sections of each specimen were made, and, on the basis of the reported findings, the following conclusions may be drawn: Zinc oxide-eugenol cement showed satisfactory properties of plasticity and dimensional stability, but it did not prove its adhesiveness to the root canal walls. It showed no signs of solubility or permeability to body fluids within the postoperative periods of this investigation. Whenever this material set in a dense mass, it showed a marked resistance to resorption. Zinc oxide-engenol cement was found to be highly irritating to the periapical tissues and caused necrosis of bone and cementum when it came in contact with them. Polymorphonuclear leukocytic infiltration was seen in the periodontal ligament and persisted for 2 weeks or more. On the other hand, when the body tissue encapsulated the zinc oxide-eugenol with a fibrous capsule, an area of loose connective tissue with cell infiltration could be seen, as a rule, between the zinc oxide-eugenol cement and the fibrous capsule.

A study of periapical overfilling in root canal treatment in the molar of rat

Abstract One hundred and nine overfilled root canals of the mesial root of first mandibular molars of rats, using a variety of materials, were studied histologically. Evidence was found that, when the overfilling root canal material was hard and compact, the surrounding tissues tended to encapsulate it. However, a zone of loose connective tissue containing many macrophages frequently formed between the capsule and the filling material. When the material was not so compact, it was found dispersed in the sections and was resorbed more rapidly. Detritus, caused by instrumentation, was often projected beyond the foramen and was dispersed in the periapical tissues. Where the excess of material entirely filled the periapical space there was necrosis of the bone. Resorption of necrotic bone and of the overfilling material occurred, both from the periodontal ligament and from the adjacent red bone marrow. Root canal material in contact with bone marrow became encapsulated more slowly than that in contact with periodontal ligament, and resorption was slower. Material in relation to the mandibular canal showed a poorly differentiated fibrous capsule. When resorption of the root left the overfilling material in direct contact with periodontal membrane, tissue reaction varied according to the nature of the material. Zinc oxide and eugenol induced a mild inflammatory reaction and was resorbed very slowly. Fillings of a resorbable paste provoked a more intense polymorphonuclear leucocyte infiltration and were rapidly resorbed.

Necrosis of the Periodontal Ligament in Root Canal Overfillings

SYNOPSIS IN INTERLINGUA NECROSE DEL LIGAMENTO PERIODONTAL INDUCITE IN LE RATTO PER UN EXCESSIVE IMPACCAMENTO DEL CANAL DE RADICE.-Esseva effectuate un studio microscopic de 48 canales de radice a excesso de impaccamento con varie materiales. Quando le excesso de material occupava le periodontal spatio apical, necrose del area adjacente al lateral ligamento periodontal esseva constatate de maniera quasi constante. Le injection vascular de gelea a tinta de China ad in le area necrotic demonstrava qu esu origine esseva in le rete del fundo alveolar. Necrose del periodontal ligamento lateral in casos de excesso de impaccamento es possibilemente correlationate con un infarcimento causate per le obstruction de ille vasos in le area apical.

A method for root canal treatment in the molar of the rat

Abstract We have described a method which permits endodontic treatment of the mesial root of the left lower first molar in the rat. The equipment required is relatively simple and can be made with materials that are readily available in any laboratory. The method permits the use of numerous and homogeneous lots of animals to further the study of experimental biologic endodontics.

Alveolodental ankylosis induced by root canal treatment in rat molars.

Abstract Alveolodental ankylosis induced by root canal treatment was studied in 253 60-day-old albino rats. Zinc oxide—eugenol, Grossman cement, and formaldehyde-containing cements, as well as pastes containing formalin, trioxymethylene, and trioxymethylene-prednisolone-acrylic spherules, were used as root canal filling materials. Ankylosis produced by either ZOE or Grossman cement was rare and was limited to the periapical area. Formaldehyde-containing cements caused severe and frequent partial ankylosis at different levels of the periodontal ligament. Total ankylosis was found in some cases. Pure formalin and 50 per cent formalin solution produced extended or total ankylosis 30 days after treatment. Trioxymethylene produced extended alveolar bone necrosis and an acute inflammatory tissue reaction. Rats treated with trioxymethylene-corticoid and acrylic spherule paste exhibited two types of tissue reaction: 1. 1. An ankylotic reaction appearing either 30 or 90 days after treatment, following cementum, periodontal ligament, and alveolar bone necrosis. 2. 2. An inflammatory reaction affecting the necrotic periodontal ligament, occasionally accompanied by huge sequestra and an encapsulating fibrous reaction.

Necrosis of cementum induced by root canal treatments in the molar teeth of rats

Abstract In order to study the causes and evolution of cementum necrosis, root canal treatment was carried out in the mesial root of the first left lower molar in 154 white rats. Animals were sacrificed from 3 to 90 days after treatment. Histological studies allowed the following conclusions to be drawn: 1. 1. Cementum necrosis due to the chemical irritation provoked by the filling material employed, and to the toxic bacterial action of detritus caused by instrumentation, was seen extending outwards from the cementodentinal junction. Necrosis became more severe as dentine thickness decreased. 2. 2. In specimens showing infarct necrosis of the periodontal ligament, or periapical abscess, necrosis of the cementum started from the periodontal surface and spread towards the cementodentinal junction. 3. 3. Resorption of the necrotic cementum was frequently observed, causing, in some instances, total removal of cementum and dentine in the apical zone. 4. 4. When the cause provoking the necrosis was not persistent and the periodontal ligament was normal, apposition of new cementum over necrotic cementum was seen occasionally.

Periodontal Changes and Dental Caries in Experimental Prediabetes

The prevalence, activity and rate of progression of dental caries, as well as the periodontal histopathology (presence or absence of pathological pockets, structure and thickness of the osseous alveolar crest, and width of the marginal periodontal ligament) in prediabetic and diabetic white rats were studied. The observations of caries activity (within the prediabetic period) were made on rats sacrificed forty-five days after being 95 per cent and 80 per cent pancreatectomized. A significant increment of caries activity was found in all aspects investigated in both groups of experimental animals with respect to normal and sham operated controls. The histopathology of the periodontium of 95 per cent pancreatectomized rats sacrificed ten months after the operation with diabetes of several months and varying degrees of hyperglycemia showed morphological alterations of the osseous alveolar crest, with significant thickening of the marginal periodontal ligament. This process could be observed very early in prediabetes in rats with normal blood sugar, no glycosuria, and normal diuresis and body weight, sacrificed three months after the operation. Even though it seems to be indisputable that alterations of carbohydrate metabolism in diabetic rats have an aggravating effect, changes in prediabetes suggest that the observed caries and lesions of the periodontium start very early and independently of the diabetic changes in carbohydrate metabolism.

Dental Caries in Diabetic and Prediabetic Rats

SYNOPSIS IN INTERLINGUA CARIE DENTAL IN RATTOs DiABETic E PREDIABETIC.—Le prevalentia, incidentia, e rapiditate evolutive de carie dental esseva studiate a base de un registration del numero de afficite e destruite dentes molar e de cavitates, si ben como del typo de carie incontrate. Un convenibile indice esseva applicate pro exprimer le grado de susceptibilitate. Statos diabetic e prediabetic esseva provocate per pancreatectomia a 95 pro cento, controlate per determinationes periodic del sucro sanguinee in stato jejun. Le condition diabetic accelerava notabilemente le establite processo de carie. Un augmento significative in le prevalentia, le incidentia, e le rapiditate evolutive esseva observate non solmente in animales con confirmate e incipiente diabete sed precocemente etiam in animales prediabetic.

Periapical Tissue Response to the Apical Plug in Root Canal Treatment

Apical plugs were produced by compressing radicular pulp and dentin chips in 157 molars from rats. Root canal fillings were performed with 15 different materials. After seven days, tissue reaction with all materials was favorable. After 30 and 90 days, materials that contained corticoids showed a good periapical response, slight cementum necrosis, and narrowing of the foramen in many instances.

Periapical tissue reaction to root canal fillings with zinc, titanium, lead, and aluminum oxides

I n the use of any root canal filling material, we believe it is necessary to determine the tissue response in the periapical area to each of the material’s ingredients. Metallic oxides have frequently been added to root canal materials. Zinc oxide is a basic ingredient in root canal sealers. Titanium dioxide is a component of AH-26i and N,