Biomedical subjects

T Baccetti

Publications and source records attributed to T Baccetti.

41 records · Page 3Linked to original sources

PubMed1993

[An analysis of the prevalence of isolated dental anomalies and of those associated with hereditary syndromes: a model for evaluating the genetic control of the dentition characteristics].

Tooth ontogenesis, morphogenesis, and eruption are under a multifactorial (genetic, epigenetic, environmental) control. The aim of this study has been a genetic appraisal of tooth developmental characteristics by means of the prevalence and patterns of association of tooth anomalies in a large sample of hereditary syndromes. MATERIALS AND METHODS. A sample of 169 hereditary syndromes exhibiting tooth abnormalities was collected from the literature: original articles were controlled in order to achieve uniformity of judgement about the definition of the dental defects. Tooth anomalies were classified according to anatomoclinical criteria: number (hypodontia/hyperdontia), shape, position, structure (enamel/dentin/cementum), size (micro-/macrodontism), eruption (precocious/delayed including unerupted teeth). Prevalence data were calculated for: 1) modes of syndrome inheritance; 2) syndromes exhibiting a single dental anomaly vs. syndromes exhibiting associated tooth abnormalities; 3) different types of tooth abnormalities; 4) isolated and associated tooth abnormalities.

Abnormalities, Multiple↗

PubMed1992

[A current update on the etiopathogenesis of palatoschisis].

By means of a review of the most recent literature, the authors report on "state of the art" about etiology and pathogenesis of cleft palate. Epithelial-mesenchymal interactions regulating growth and orientation of palatal shelves, as well as teratogenic effects on such ultrastructural development control by endogenous and exogenous substances, are described.

Abnormalities, Drug-Induced↗

PubMed1991

[The dentomaxillofacial characteristics of the Prader-Labhart-Willi syndrome. A clinical case report].

The authors describe the clinical and cephalometric characteristics of a case of Prader-Labhart-Willi syndrome (obesity, hypogonadism, oligophrenia, hypotonia, small hands and feet). Taurodontism and enamel-dentine dysplasia are reported as the main dental features. The craniofacial region shows an increased bony interorbital distance and a low level of the cribriform plate of the ethmoid bone. The possibility that these anomalies could be related to the etiopathogenesis of the syndrome is discussed.

Cephalometry↗

PubMedDate not supplied

Resistance to fracture of metal ceramic and all-ceramic crowns.

This study evaluated the fracture resistance of three types of all-ceramic crowns and compared these to the fracture values of metal ceramics. Uniform metal ceramic specimens; veneered, cast glass-ceramic; and porcelain fused to two different dispersion-strengthened ceramic cores (Hi-Ceram and In-Ceram) were investigated. The metal ceramic specimens demonstrated a significantly higher resistance to fracture than did the Hi-Ceram or veneered glass-ceramic units but did not significantly differ from the In-Ceram specimens. The metal ceramic crowns showed cracks only in the ceramic layer, whereas the all-ceramic specimens underwent global fracture.

Aluminum Oxide↗

PubMedDate not supplied

[Heredity and environment in the genesis, epigenesis and evolution of the orofacial area].

Genetic and evolutionary aspects of the dento-facial complex are described according to the concept of heredity as a force of preservation for the human species, though ruled by natural selection and by mutational changes. Ontogenesis and growth of the oral structures reflect mutual regulations between genes and environmental factors. Therefore, the authors carry out an analysis of environmental and constitutional factors affecting dental and facial development. Three levels are identified: individual morphogenesis and growth; actual heredity of parietal dento-facial traits; role and meaning of teeth, jaws and temporo-mandibular joint during evolution leading to Homo sapiens sapiens. As far as individual development is concerned, genes provide only the input for initial cell proliferation and/or differentiation. Further on, growth and morphogenesis of oro-facial structures takes place by means of cell-to-cell and cell-to-substrate interactions. The final, structural result is due to reciprocal interactions among developing structures: muscles modify bone, teeth alignment influences bony bases alignment, ecc. Each structure is genetically determined (teeth, bones, muscles) and each structure carries out epigenetic regulations on other structures: no structure is secluded from biological function of the organism. The inheritance of oro-facial "traits", then, is hardly valuable. First of all, "traits" actually do not exist: they are the product of complex, multifactorial biological mechanisms. Moreover, facial characteristics are affected by polygenic regulation, each gene often showing pleiotropic effects. It has been calculated that 85-90% of facial dimensions in due to epigenetic modifications. Evolution and phylogenesis give evidence about the deep environmental influence on oro-facial morphology. Apart from certain molecular features regarding tooth structure (several dental proteins are today the same as those of the first Vertebrates who lived 500 millions of years ago), tooth number, form, and size depend upon environmental factors. Therefore, dentistry has the important task to preserve fundamental characteristics of dentition, and to intercept environmental pathogenetic factors, as dentition represents a precious instrument for the survival of the human species.

Biological Evolution↗