Effects of Prolonged Chronic Vitamin A Deficiency in the Rat With Special Reference to Odontomas.

Orten, Aline Underhill; Burn, Charlotte C.; Smith, Arthur H.

doi:10.3181/00379727-36-9124p

Cited by 17 publications

(4 citation statements)

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“…A few papers have described proliferative lesions (odontomas or ameloblastomas) of the incisors in rodents as rare spontaneous neoplasms (5,8,22,27) or as hamartomas in inbred (32) or genetically altered (14) rodents. Dental tumors can be induced by treatment with carcinogenic (3,7,9,10) or mitogenic (26) agents, by radiation (6), by dietary imbalances (23,28), and by viruses (12,15). The possibility that chronic dental disease in a significant number of animals may result in stress, unthriftiness, and a general shortening of survival times for animals in chronic toxicology/oncogenicity studies has rarely been considered or addressed.…”

Section: Introductionmentioning

confidence: 99%

Dental Dysplasia in Rats and Mice

Losco¹

1995

Toxicol Pathol

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Malformations of the maxillary incisors, diagnosed as dental dysplasia, were observed as a spontaneous background lesion in 3% (females) to 9% (males) of CD-1® mice and 14.5% (females) to 10.5% (males) of CD@ (Sprague-Dawley) rats in a chronic inhalation study. Lesions were reported grossly as overgrown, maloccluded, or malformed incisors. Microscopic findings included tooth pulp and periodontal abscesses, fractured and necrotic teeth, periodontal cysts, malformations of the incisor roots, and expansile masses, including odontomas, of the incisor roots. Development of lesions followed a pattern of tooth pulp necrosis and/or traumatic disruption of the epithelial root sheath at the base of the tooth. Feeding a powdered ration, which reduced the normal wearing of the incisors, and repeated clipping of overgrown incisors were believed to contribute to the incidence of disease.

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Section: Introductionmentioning

confidence: 99%

Dental Dysplasia in Rats and Mice

Losco¹

1995

Toxicol Pathol

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“…In the rat, certain deficiencies have been shown to result in the appear ance of specific tumors not normally ob served in the strain of rats used, or to pro duce an increase in the incidence of spe cific tumors. The most notable of these involve the thyroid gland (12), forestomach (13,14), maxilla (15), and liver (16).…”

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confidence: 99%

Tumor Incidence Patterns and Nutrition in the Rat

Ross

Brás

1965

The Journal of Nutrition

183

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Levels of caloric and of protein intake were demonstrated to have a modifying influence on tumor incidence patterns in the male rat. The 5 uniform life long dietary regimens used differed only in allotments and intakes of protein (casein), carbohydrate (sucrose) or of total calories. Age-specific rate tables and tumor in cidence ratios aided in assessment of the nutritional effects. Total tumor risk was directly and exponentially related to caloric intake, but time differences for develop ment of each of the incidence patterns were related inversely to caloric intake. Among all the groups tumor incidences formed an exponential continuum when related to growth rate in early life and mature body weight. Within each dietary group, rats of heavier weight had greater tumor risk than lighter rats. Occurrence, the proportional incidence and the malignancy of certain tumors correlated with the level of protein intake. Malignant lymphomas were predominant in rats with high protein intake, whereas fibromas and fibrosarcomas predominated in rats with low protein intake. Tumor incidence patterns differed quantitatively, qualitatively or both. Thus, in 2 groups with identical caloric intake, risk for all tumor types was similar but the group with higher protein had a greater risk for malignancy. Rate patterns for benign tumors, but not for malignant tumors, were dependent upon the mortality rate patterns of their re spective populations. Lowest incidence, greatest delay in time of occurrence, absence of malignant epithelial tumors and greatest life expectancy, were observed when in takes of protein, carbohydrate and total calories were low.

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“…Moreover, if the tooth grows slower than usual, the ameloblasts regress earlier and, conversely, if growth is accelerated, for instance in young animals and in animals with malocclusion, the ameloblasts remain columnar up to the gingival margin (9,19). Squamous metaplasia of enamel epithelium occurs with inflammation but also in vitamin A deficiency (13).…”

Section: X50 B)mentioning

confidence: 99%

“…Vitamin A deficiency, for example, does not affect the tooth through alteration of calcium metabolism, but it affects odontoblast histodifferentiation (16), and the formation of dentin is altered. Cords of odontogenic epithelium invade the pulp and give rise to islands of atypical dentin, or to the formation of denticles, and even dentinomas or odontomas may develop as a consequence of vitamin A deficiency (13,25). Vitamin D hypervitaminosis alters the incisors indeed by affecting Ca homeostasis (6).…”

Section: Metabolic Changesmentioning

confidence: 99%

Review Article

1996

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Microscopic examination of the incisors of rats and mice may reveal toxicologically significant changes. First, the incisor morphology reflects the nutritional status of the animal: fluctuations of mineral metabolism and vitamin availability are disclosed by the rodent incisors, because the incisors continue to grow during life. Similarly, direct or indirect changes of mineral metabolism by a test substance are reflected in the morphological appearance of the incisor dentin. In addition, hormonal disturbances may give rise to typical structural alterations of the incisor in the test animal. Certain chemicals may have deleterious effects upon the odontogenic tissues, resulting in tooth malformation and malocclusion and eventually in odontomas. Apparent nasal tumors may turn out to be of dental origin. Nasal luminal masses that are discussed within this scope are dental malformation, dental callus, and true odontogenic tumors. According to our experience, odontogenic tumors might possibly develop within the scope of a reaction to mechanical tooth trauma as well. In carcinogenicity studies, this consideration deserves attention when evaluating treatment-related putative odontogenic tumors.

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Effects of Prolonged Chronic Vitamin A Deficiency in the Rat With Special Reference to Odontomas.

Cited by 17 publications

References 0 publications

Dental Dysplasia in Rats and Mice

Dental Dysplasia in Rats and Mice

Tumor Incidence Patterns and Nutrition in the Rat

Review Article

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