Geoffrey H. Sperber

First Year of Life: Prenatal Craniofacial Development

Abstract And surely we are all out of the computation of our age, and every man is some months elder than he bethinks him; for we live, move, have a being and are subject to the actions of the elements, and the malice of diseases, in that other World, the truest Microcosm, the Womb of our Mother. Sir Thomas Browne Religio Medici, 1642

Dental manifestations of dermatologic conditions

BACKGROUND Cutaneous disorders can be associated with a wide variety of dental manifestations that should be familiar to dermatologists. OBJECTIVE We sought to describe the development of the teeth, explain current dental terms, and review the dental manifestations of some dermatologic conditions. METHODS A MEDLINE search (1966-May 2007) was performed to find relevant articles pertaining to dental manifestations of dermatologic conditions. RESULTS Dental manifestations are associated with a wide variety of skin diseases that include genetic, infectious, inflammatory, and immune disorders. LIMITATIONS The review is broad and focuses on commonly described manifestations. CONCLUSIONS An appreciation and understanding of dental signs can aid in the diagnosis and treatment of many skin conditions.

Biological Reactions to Experimental Dental Amalgams

SYNOPSIS IN INTERLINGUA REACTIONES BIOLOGIC A DENTAL AMALGAMAS EXPERIMENTAL.—Esseva testate le reactiones de tissu conjunctive de rattos a novemente disveloppate alligatos, fortificate per dispersion, de cupro e argento, tanto sol como etiam in combination con fluoruro, con le objectivo de evalutar lor innocentia in uso clinic como materiales restaurative in amalgamas dental. Varie concentrationes de fluoruro de calcium esseva addite al amalgamas de alligato e mercurio in le fabrication experimental de materiales restaurative con potentia inhibitori anti carie, e iste combinationes esseva inserite in le subcutanee tissus conjunctive de rattos durante periodos de usque a 32 dies. Le examine histologic de iste tissus revelava que le amalgamas a alligato de cupro e argento esseva non minus innocente que le currentemente usate amalgamas a alligato de argento e stanno. Le addition de 1 pro cento (per peso) de fluoruro de calcium a amalgamas a alligato de argento e stanno causava prolongate irritation in le tissus. Le addition de 0,5 pro cento o minus (per peso) de fluoruro de calcium a amalgamas a alligato de cupro e argento causava nulle inusual responsa inflammatori, e esseva considerate como salve in le uso clinic como material de restauration dental. Le minime procentage (per peso) de fluoruro de calcium capace a producer le maxime effecto inhibitori anti carie va esser determinate a base del resultatos de prolongate essayos clinic.

The genetics of odontogenesis : implications in dental anthropology and palaeo-odontology : hominid studies

Palaeoanthropology and forensic odontology rely significantly on detailed dental morphology that is ultimately the phenotypic expression of the underlying genotype and developmental phenomena. Odontogenesis is the consequence of a complex series of molecular interactions controlled by epigenetic signals acting on embryonic epithelial-mesenchymal tissues of ectodermal, neural crest and mesodermal origin. Of the estimated 24 847 genes of the human genome (Pearson, 2003) some 200 or more genes have been directly or indirectly implicated in tooth development (http://bite-it.helsinki.fi). The loci of these genes on the 22 pairs of autosomes and the pair of sex chromosomes are being identified by their mutations that give rise to phenotypic dental abnormalities. The sequential cascades of stages from initiation through the bud, cap, bell, mineralisation, root formation and eruption of teeth are all under genetic control but subject to environmental influences. Identification of specific genes with clinical phenotypes provides invaluable clues to familial, racial and evolutionary affinities, all of jurisprudential, heredity and evolutionary significance to odontologists. Combining the genetics of odontogenesis with forensic evidence and palaeoanthropological fossil data provides an unparalleled source of information on heredity, environmental and evolutionary events through teeth, the most durable of all biological structures after death. It is paradoxical that teeth are most susceptible to decay during life, but postmortem are the last structures to disintegrate. Teeth truly tell tales of the living and the dead.

Anatomy of the circle of Willis in three cases of human fetal synophthalmic holoprosencephaly

In three human fetuses with synophthalmic holoprosencephaly (8, 14, 23 weeks post conceptionem) the circle of Willis was studied using serial histological sections and computer aided three dimensional reconstruction methods. This structure was abnormal in all cases. In two cases the anterior communicating arteries were absent. In all cases the anterior cerebral arteries could not be found. One case showed an incomplete circle with no posterior communicating artery. The results indicate that the malformation of the circle of Willis reflects the malformation of the brain.

Cranio-facial skeletal development in three human synophthalmic holoprosencephalic fetuses

In three human fetuses with synophthalmic holoprosencephaly (8, 14, 23 wks. p.c.) and two normal human fetuses (9 and 13 wks. p.c.) the anatomy of the cranial base, facial cranium and their relation to the notochord was studied using serial histological sections and computer aided three-dimensional reconstruction methods. Mesethmoidal cartilage differentiation was variably deficient in all three holoprosencephalic cases. The premaxillary bones were rudimentary with missing tooth buds. The development of the sphenoid bone was defective in two of the holoprosencephalic cases (8, 14 wks. p.c.). The notochord terminated normally within the sphenoid body in all investigated cases. Our results indicate that in holoprosencephaly there is a general defect in the midline cranial cartilage differentiation rostral to the notochord.

Anodontia: Two cases of different etiology☆

Abstract Two cases of partial anodontia involving both the deciduous and the permanent dentitions have been described. A consideration of the histories indicated that each case had a different etiology. One case appeared to have been inherited, whereas the other occurred for the first time in the familys history. On the basis of differing etiological factors, it was postulated that two types of anodontia exist, the inherited type being termed “phylogenetic” and the “de novo” type being termed “ontogenetic.”

Computer graphic three-dimensional reconstruction of normal human embryo morphogenesis

Three-dimensional computer graphic reconstructions of four human embryos at Carnegie stages 11 to 23 portray the relationships and dimensions of individual organ systems. This paper illustrates the cranial, neural, pharyngeal, gut, vascular and nephric architecture in these developing embryos. This technology can be applied to in situ hybridization and immunohistochemistry to map zones and times of developmental gene activity.

3D-reconstruction of craniofacial structures of a human anencephalic fetus. Case report

It was the purpose of this study to investigate the craniofacial bones, cartilages and major blood vessels of a human anencephalic fetus and to describe the malformations of these structures accompanying this developmental disruption. The head of a 16 week old human fetus with anencephaly was serially sectioned and the craniofacial bones, cartilages and major blood vessels were traced and reconstructed by 3D-computer technology. The sphenoidal, temporal and occipital bones showed severe malformations, whereas the bones of the facial cranium were normally developed. Both internal carotid arteries ended within the cerebro-vascular area with no further branches. The vertebral arteries also ended within the cerebro-vascular area. No arterial circle of Willis was developed. The notochord terminated normally in the sphenoid body. The observations indicate that the possible reason for this malformation was non-closure of the anterior neuropore of the neural tube. The normal termination of the notochord suggests that it had no influence on the pathogenesis of this malformation. The malformations of the temporal and occipital bones are contradictory to the hypothesis of Marin-Padilla (1991) that anencephaly is caused by a maldevelopment of the sphenoidal bone.

The enigma of cephalogenesis

The cascade of developmental events in cephalogenesis is initiated by specific genes being transcribed and translated into polypeptides and proteins that form the structural basis of cells and tissues. These become differentiated into the complex organs of the craniofacies by the actions of signalling transducers, growth factors, and morphogens. Defects of development may be traced back through this sequence to determine the specific etiologic factors responsible for dysmorphogenesis. Molecular biology and embryology are becoming increasingly significant for clinicians.