Francisco C.H. Devoto

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.

The origin and distribution of the elements of the human mandibular retromolar canal

Abstract The nature of the content of the mandibular retromolar canal, as well as the origin and fate of its elements, were studied in eighteen human heads that had been preserved in formaldehyde. The canal was found in thirteen of the heads (72%), in five of which (27%) it was bilateral. The retromolar canal originates from the inferior dental canal and, after describing a recurrent path, it ends either in the retromolar foramen or in surrounding foramina. The elements occupying it are derived from their inferior dental homologues. The most frequently found components, in decreasing order, were a myelinated nerve, one or more arterioles and one or more venules. After leaving the body of the mandible, these elements are distributed mostly upon the temporal tendon, the buccinator muscle, the most posterior zone of the alveolar process, and the third mandibular molar. The different paths which the retromolar mandibular canal may describe could be considered as a trait of discontinuous variation, useful to typify ethnological material such as is studied in this paper, coming from a mestizo population that arose from the cross-marriage of Europeans and Argentine aborigines.

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.

Shovel-Shaped Incisors in a Northwestern Argentine Population

The prevalence and the inheritance of shovel-shaped incisors were studied in children from northwestern Argentine provinces. One hundred percent of the deciduous and permanent incisors were shovel shaped, and a high frequency of the S-gene in the permanent dentition was found. These findings demonstrate a strong Mongoloid genetic component in this population.

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.

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.

Molar Size Sequences in a Mixed Population of the Northwest Argentine Highlands

Garn, Lewis, and Kerewsky (Am Anthropol 66: 587-592, 1964 and Science 142:1060, 1963) have shown that the molar size sequence, second molar greater than first molar (M2 > Ml), is reasonably common in contemporary populations. They also have stated that the prevalence of the size polymorphism, the apparent differences between recent populations, and hereditary factors indicate that relative molar size may be useful at the species level and lesser classifications. This study deals with the molar size sequence in San Antonio de los Cobres, Salta (SAC), where Caucasian mixture with the autochthonous Andide population is easily detected (Rev Asoc Odontol Argent 57:3, 1969). for maxillary pairs, except for SAC-Pima. The increasing order of differences for SAC was Aleuts, Pima, whites; for Aleuts: SAC, Pima, whites; for Pima: whites, SAC, Aleuts in the maxilla and SAC, whites, Aleuts in the mandible; and for whites: Pima, SAC, Aleuts. The results indicate that the relative molar size polymorphism follows a definite racial pattern. Consistent differences were found among the four populations considered. Furthermore, the order of the differences agrees with the racial history of each group. The similarity between Ohio whites and Pima Indians can be attributed to Caucasian mixture in the Indian population, which occurred after conquest of Indian territories by Europeans. The difference

Shovel-Shaped Incisors in Pre-Columbian Tastilian Indians

The high prevalence of dental shoveling is considered one of the main components of the Mongoloid dental complex (C. F. A. MOORREES, The Aleut Dentition, 1957, p 6; K. HANIHARA, Zinruigaku Zassi, 74:9-20, 1966). However, data on South American Indians are scanty. Shoveling has been described in contemporary populations of Ecuador (A. SANTIANA and J. D. PALTAN, La dentadura en los indios de Imbabura y Chimborazo, 1962, pp 31-33), Venezuela (Ch. BREWER-CARIAS, Antropologia dental en los Indios Soto, 1964, pp 50-56), Brasil (R. M. DESMET, Bull Group Int Rech Sci Stomat 9:401-414, 1966), Peru (P. W. GOAZ and M. C. MILLER, J Dent Res 45:106-119, 1966), and Argentina (F. C. H. DEVOTO, N. H. ARIAS, S. RINGUELET, and N. H. PALMA, J Dent Res 47:820-823, 1968). There are also some references to shovelshaped incisors in pre-Columbian South American Indians (R. W. LEIGH, Amer J Phys Anthrop 22:267-296, 1937; E. S. CUNHA, Historia da Odontologia no Brasil, 1963, pp 59, 113; E. S. CUNHA, Rev Mus Paulista 14:523-529, 1963; F. C. H. DEVOTo and N. H. ARIAS, J Dent Res 46:1478, 1967). This paper deals with shovel-shaped incisors in Tastilian skulls recently unearthed at Santa Rosa de Tastil, Salta, Argentina. The bed is located 3,200 meters above sea level on the Eastern border of La Puna, a vast plateau surrounded by Los Andes. The Tastilian bed has been dated to the year 1420 AD by means of 14C. Only 13 of the 62 Tastilian skulls had incisors. Hrdlickas subjective scale (Amer J Phys Anthrop 3:429-465, 1920) was used to classify degrees of shoveling; shovel, semishovel, trace shovel, and no shovel. The appearance of labial marginal ridges (A. A. DAHLBERG and 0. MIKKELSEN, Amer J Phys Anthrop 5:234-235, 1947; R. G. SNYDER, J Dent Res 39:361-364, 1960) also was recorded. The 13 specimens had shovel-shaped incisors. All of the maxillary first incisors, and eight of nine specimens with maxillary second incisors were shovel-shaped. The ninth was semishoveled. The mandibular incisors had milder degrees of shoveling. Two of the three available sets of maxillary first incisors had mesial and distal labial marginal ridges and the third had only the mesial ridge. Dental shoveling appeared to be associated with the dental tubercle (TH. E. DE JONGECOHEN, Z Anat Entwicklungsgesch 78:277-307, 1926), which in the maxillary first incisors showed a decided variability. In some instances the tubercles appeared as fingerlike projections that extended incisally, in other instances tubercles were expressed moderately and in other instances they were absent. Because of attrition, the dental tubercle of the maxillary first incisors could not be studied. Also a cleft was

Growth of Rats' Lower Incisor Teeth after Unilateral Section of Alveolar Nerve

SYNOPSIS IN INTERLINGUA CRESCENTIA DE DENTES INFERO-INCISORI DEL RATTO POST DISSECTION UNILATERAL DE NERVO ALVEOLAR. -Le dentes al latere operate erumpeva con le mesme rapiditate que le dentes correspondente de pseudo-operate rattos de controlo, sed le correspondente dentes heterolateral del operate rattos manifestava un fortemente reducite rapiditate de eruption. Le relentate eruption del heterolateral dentes incisori in le operate rattos es le ration que explica que plure autores ha asserite que le dentes incisori al latere operate erumpeva relentatemente post dissection de nervo alveolar. Illes utilisava le heterolateral dentes incisori como controlo, sin considerar le possibilitate de un effecto bilateral.