Barry K Berkovitz

King's College London | KCL · Department of Anatomy and Human Sciences

Dentine is a moderately mineralized tough tissue which supports the harder, but more brittle, enamel, or enameloid, at the functional surface. Dentine owes its toughness to the combination of collagen fibers and numerous, very small crystals of hydroxyapatite. It is produced by odontoblasts, which originate from the dental papilla, a derivative of...

The amphibians prey on small invertebrates. Their teeth are sharply pointed, with one cusp in larvae and usually two in the adult. Adult teeth are usually divided into a distal functional tip and a basal pedicel, ankylosed to the jaw bone. The burrowing caecilians have robust skulls and relatively large, strong piercing teeth in both jaws. Other am...

The jaws of elasmobranchs are suspended from the chondrocranium, and jaw protrusion during feeding enhances prey capture. Although all elasmobranchs have the same mode of tooth attachment and continuous replacement, tooth form varies considerably and includes conical piercing teeth, blade-like slicing teeth, and rounded crushing teeth. Most sharks...

Most batoids (skates and rays) feed on slow-moving or sessile prey at the sea bottom. Feeding is facilitated by ventrally directed mouths and an especially mobile form of jaw suspension (euhyostyly), which enables them to retrieve prey from the substratum. The dentition is homodont. In most batoids the teeth are small, numerous, and adapted to gras...

Enamel and enameloid are hypermineralized tissues, which are located at the functional surfaces of teeth and break down the mechanical resistance of food items. Enamel in mammals, reptiles, sarcopterygians, and adult amphibians varies histologically but not biochemically. Enameloid (teleosts, elasmobranchs, larval amphibians) varies in both respect...

Most lizards are carnivorous: small species prey on invertebrates and larger species take eggs, birds, and vertebrates. The dentition is usually homodont, consisting of sharply pointed, piercing teeth or sharp-edged cutting teeth. In those dentitions that are heterodont, the degree of variation is relatively small but in durophagous species (eg, Dr...

Nearly all non-mammalian vertebrates are polyphyodont: that is, the teeth are replaced continually throughout life. Polyphyodonty has several functions. First, increases in number, size, or both of successive generations of teeth is an essential component of the growth of the dentition. Second, morphological changes in successive generations can al...

Lampreys and hagfishes form an apparently monophyletic group of jawless vertebrates that lack true teeth or other mineralized tissues. They do, however, possess keratinized tooth-like structures that are used in feeding. It has been suggested that the “teeth” of hagfishes may contain proteins associated with enamel and hence may be related to true...

Crocodylians live in and near water. Unlike other reptiles they have a secondary palate and feeding under water is facilitated by the ability to separate the respiratory and feeding tracts. Most crocodylians feed on a wide variety of prey, including invertebrates, amphibians, reptiles, birds, and mammals, but some specialize in eating fish. The sku...

Snakes mostly prey on living animals which are swallowed whole. Snakes kill prey by biting (sometimes with envenomation) or by constriction, which causes asphyxiation. The dentitions are homodont and consist of very sharp, recurved teeth firmly ankylosed to the jaw bones. The cranium is robustly constructed and has no mobile intracranial joints as...

Teeth develop at the interface between epithelium and ectomesenchyme, a derivative of the cranial neural crest. Oral or pharyngeal epithelium grows inwards to form a dental epithelial cap surrounding a mass of ectomesenchyme cells which comprise the dental papilla and dental follicle. The dental epithelium may be derived directly from the oral/phar...

The Osteichthyes—fishes with bony skeletons—comprises the Sarcopterygii (coelacanth and lungfishes) and the Actinopterygii, the latter of which includes the largest class of vertebrates, the Teleostei. The evolutionary radiation of the Teleostei has been spectacular and the dentition has played a major part in trophic adaptation. The main changes i...

The Teeth of Non-Mammalian Vertebrates is the first comprehensive publication devoted to the teeth and dentitions of living fishes, amphibians and reptiles. The book presents a comprehensive survey of the amazing variety of tooth forms among non-mammalian vertebrates, based on descriptions of approximately 400 species belonging to about 160 familie...

John Tomes was initially destined for a career in medicine but after being introduced to dental histology, changed careers and gave the first series of lectures on dentistry in Middlesex Hospital. His early academic career resulted in four major papers on the structure of teeth and bone that were read before the Royal Society, establishing his repu...

While most books on dentistry describe the clinical and medical procedures involved, this book expands the field to examine the role of dentistry and teeth in everything from biology to biography. This book offers facts and figures regarding famous historical figures, such as John Hunter, Dr Crippen, Doc Holliday, and Paul Revere, exploring how the...

Odontomas are hamartomatous malformations of odontogenic origin composed of all the structures that form the tooth. Pigmentation associated with odontomas is rare, with only two cases reported in the literature. The genesis of this composite malformation is attributable to the organizational failure of the developing odontogenic apparatus leading t...

The development of oral cancer proceeds through discrete molecular changes that are acquired from loss of genomic integrity after continued exposure to environmental risk factors. It is preceded in the majority of cases by clinically evident oral potentially malignant disorders, the most common of which is leukoplakia. Early detection of these oral...

A study of the tissues of the teeth and jaws in piranhas, using the scanning electron microscope and various techniques of light microscopy, revealed many dental adaptations related to the specialized feeding habits of these carnivorous fishes. The dentition is primarily sectorial, although some anterior teeth may be used in grasping. The scissor-l...

As the Crocodilia are the only non-mammalian vertebrates with tooth sockets, the attachment tissues of the teeth were studied in Caiman sclerops mainly at the ultrastructural level and were compared with those of mammals. All three attachment tissues (alveolar bone, cementum and periodontal ligament) in the Caiman showed both similarities and diffe...

A radiological study of the developing dentition of the domestic albino ferret has revealed the presence of four upper and three lower deciduous functionless incisor teeth in each half of the jaw. The presence of the additional upper incisor tooth can only be accounted for in two ways: (1) It arose as the result of a gene mutation within the closed...

The present paper reports observations from serial sections of five pouch-young specimens on the early stages of tooth ontogeny in the post-incisor dentition of Trichosurus vulpecula. The order of cusp development and calcification for the molariform teeth is recorded and closely resembles that of placentals. Some features concerning the developmen...

Within each jaw quadrant of piranhas (Serrasalmus), the teeth develop and are replaced almost synchronously, replacement being effected in a very short time relative to the functional life of the teeth. The order of replacement of the four quadrants is more variable and several patterns were observed in living specimens, although most commonly the...

Repeated tooth initiation occurs often in nonmammalian vertebrates (polyphyodontism), recurrently linked with tooth shedding and in a definite order of succession. Regulation of this process has not been genetically defined and it is unclear if the mechanisms for constant generation of replacement teeth (secondary dentition) are similar to those us...

To investigate whether there is a difference in the density of Merkel cells between the gingiva of dentate and edentate subjects. One hundred and two blocks of human mandibular (n=55) and maxillary (n=47) gingiva from 69 white skinned individuals (44 males, 25 females, mean age 70.1 years, range 42--92 years) were analysed. Twenty-six individuals h...

The aim of this study was to analyse the immunohistochemical differentiation profile of the stratified squamous epithelium of the adult human lip. Full-thickness lower lips taken from 31 cadavers were analysed. Sections were stained with haematoxylin and eosin, periodic acid-Schiff (PAS), cytokeratins (CK), loricrin, involucrin, profilaggrin and fi...

This paper reviews certain structural aspects of the periodontal ligament. These include collagen (type, crimping and fibril diameters), ground substance (functions), cells (fibroblast morphology, cell heterogenicity and distinguishing of cell phenotypes, cell kinetics, 'foetal' characteristics), nerves (presence of neuropeptides) and blood vessels...

The present study details structural aspects of the cells of the rat intra-articular disc (IAD) of the temporomandibular joint. At the light and electron microscope level, the outline of the cells varied, although a number appeared oval/rounded. Ultrastructurally, the cells contained moderate amounts of the intracellular organelles associated with...

The skeleton of Caroline Crachami is a rare historical example of primordial microcephalic dwarfism (PMD). Studies show the condition to be heterogeneous, with at least three types, for which the assessment criteria rely on descriptive evaluations and/or simple measures with regard to cranial features. Advances in noninvasive imaging allow for a mo...

The ultrastructural appearance of the human intra-articular disc (IAD) was investigated in three discs that had been surgically removed due to disease from three female patients aged 47, 50, and 54 years of age. Regions of the IAD were selected from central areas that appeared to be least affected by disease. Sections were fixed in 2.5 per cent glu...

Retinoic acid is an important signalling molecule in embryological development and continues to be important in the adult animal because it modulates growth and differentiation in many epithelial tissues. The distribution of the enzyme retinaldehyde dehydrogenase-2 (RALDH 2), which is involved in the synthesis of retinoic acid, was studied using im...

Naked mole-rats Heterocephalus glaber are highly social hystricomorph rodents endemic to the arid regions of East Africa. Living entirely underground, they excavate an extensive system of tunnels with their continuously growing extra-buccal incisors. The majority of the burrow is composed of foraging tunnels, constructed in search of the undergroun...

Cells in the intra-articular disc of the temporomandibular joint were studied ultrastructurally at three different ages to investigate any age changes. Rats aged 2, 15.5 months, and 2.5 years, and marmosets aged 21 months, 7 years, and between 10.5 and 14 years were studied. In the first two age groups of the rat and the first of the marmoset, the...

Cytokeratin (CK) 20 is a low molecular-weight intermediate filament reportedly expressed only by benign and malignant gastrointestinal epithelium, urothelium and Merkel cells. The main aims here were to map its expression in normal oral mucosa of humans and other mammals, and to determine whether it was expressed by abnormal human oral epithelium....

The presence of crimping within soft fibrous connective tissues has a considerable role in determining the biomechanical properties of the tissue. However, there is little or no information on crimping of collagen in the human temporomandibular joint. To remedy this situation, the presence and nature of any crimping was studied in sections of human...

Very occasional reference is made to the presence of collagen crimps in the fibre bundles of the intra-articular disc (IAD) of the temporomandibular joint (TMJ). As the crimp structure may confer important biomechanical properties on the IAD, the present study was undertaken to determine its distribution in a variety of mammals, including humans. I...

In this field there has been an explosion of information generated by scientific research. One of the beneficiaries of this has been the study of morphology, where new techniques and analyses have led to insights into a wide range of topics. Advances in genetics, histology, microstructure, biomechanics and morphometrics have allowed researchers to...

Cells in the intra-articular disc of the temporomandibular joint of the rat, guinea pig, rabbit, ferret, marmoset and sheep were studied at the ultrastructural level. The cells were generally rounded in outline and possessed moderate amounts of roughened endoplasmic reticulum and other organelles associated with protein synthesis and secretion. No...

The aim of this study was to determine the degree to which the epidermis and oral epithelium of species other than man express cytokeratin (CK) intermediate filaments, which are markers of epithelial differentiation. Fixed, wax-embedded samples of skin, buccal mucosa and gingiva from rhesus monkey, marmoset, cow, sheep, pig, ferret, hamster, axolot...

The aim of this study was to determine the degree to which the epidermis and oral epithelium of species other than man express cytokeratin (CK) intermediate filaments, which are markers of epithelial differentiation. Fixed, wax-embedded samples of skin, buccal mucosa and gingiva from rhesus monkey, marmoset, cow, sheep, pig, ferret, hamster, axolot...

Caroline Crachami (C.C.) considered to have had the Seckel syndrome was one of the most extreme cases of dwarfism ever recorded. Reputedly born in Sicily in 1815, she attracted much attention when exhibited in England before her death on 3 June 1824. Although she is said to have been 9 years old at death, published descriptions give her a dental ag...

With the development of monoclonal antibodies, the intermediate filaments of the cytoskeleton have attracted a great deal of interest in the last twenty years. Because they are highly antigenic, they could be easily identified using immunohistochemical methods and their specificity for one type of cell offered possibilities in the field of diagnost...

Caroline Crachami (C.C.) considered to have had the Seckel syndrome was one of the most extreme cases of dwarfism ever recorded. Reputedly born in Sicily in 1815, she attracted much attention when exhibited in England before her death on 3 June 1824. Although she is said to have been 9 years old at death, published descriptions give her a dental ag...

The aim of this study was to determine the structure of the bovine periodontal ligament, with special reference to epithelial cell rests (ECR) and their cytokeratin content. Periodontal ligament was obtained from bovine molar teeth and studied at both the light microscopic and electron microscopic levels. Cytokeratin content was determined using im...

The distribution of cellular retinoic acid-binding protein (CRABPI) and cellular retinol binding protein (CRBPI) was studied in a series of prenatal and early postnatal rats, covering the main stages of development and eruption of the molar teeth. CRABPI positive cells were found in the mesenchymal cells of the dental follicle from the cap stage an...

Retinoids are important molecules in various aspects of embryological development. Here the distribution of cellular retinoic acid-binding protein I (CRABPI) was studied in the continuously growing incisor of adult rats using an affinity-purified rabbit polyclonal antibody. CRABPI was present throughout the presecretory and secretory ameloblast lay...

The rate of eruption of rat mandibular incisors was either increased by cutting one tooth out of occlusion or eliminated by means of pinning. The effects of such changes in eruption rate on the sulphated glycosylaminoglycan content of the periodontal ligaments was analysed. The length of the enamel secretory zone and the composition of the developi...

As retinoic acid is an important signaling molecule during embryological development. Since periodontal tissues are thought to have fetal-like properties, the present study was to determine the presence and distribution of cellular retinoic acid-binding protein I(CRABPI) in the periodontal tissues of the rat. Following demineralization, wax section...

To determine collagen fibril diameter distributions in the chordae tendineae and to see whether there are any differences between right and left sides of the human heart. Collagen fibril diameters and the percentage volume occupied by collagen fibrils (as opposed to ground substance) were determined by means of a planimeter with a digitising tablet...

Collagen fibril diameters were quantified in two regions of the articular disc of this joint. One region was the thinner, translucent central part of the disc; the other was from the thicker, opaque peripheral part more anteriorly. Mean collagen fibril diameters in the thicker zone were small and had a unimodal distribution. In contrast, mean colla...

A sample of individuals with different unilateral pathologies affecting the masticatory apparatus has been studied. Replicas of the same teeth (first or second molar) on both sides have been obtained and observed by SEM. The number, length and orientation of buccal striations have been determined for each individual. Differences in the microwear pa...

This quantitative ultrastructural analysis was made on articular discs from four guinea pigs and four cats. Mean diameters of collagen fibrils were small (approximately 45 nm) and showed unimodal distributions. These features are consistent for connective tissues subjected to compressional forces. The relatively high percentage volume of the extrac...

Collagen fibril diameters and the volume occupied by collagen were quantified at the ultrastructural level in the chordae tendineae of the rabbit and the sheep. Collagen fibril diameter distribution was unimodal and significant differences were found between values on the left and right sides, those on the left being greater than those on the right...

A quantitative ultrastructural study was made of the fibroblasts of the enamel-related connective tissue and periodontal ligament of the rat incisor. The two populations of fibroblasts were very similar in morphology, the only difference found in the parameters measured being the increased number of microtubules in the enamel-related connective tis...

A quantitative structural analysis of the synthetic and degradative organelles of fibroblasts of rat incisor and molar periodontal ligaments was conducted. The results showed that in these tissues which are reported to have significantly different rates of turnover of their functional matrix collagen the rate of synthetic activity was the same. How...

The development of the periodontal ligament was investigated from serial sections of the mandibles of ferrets ranging in age from 42 days to 66 days post partum. Both succedaneous and non-succedaneous teeth were studied and similarities were seen in both types of tooth. No significant amounts of alveolar bone were observed being deposited beneath t...

The cause of delayed eruption is usually obvious and treatable (as with lack of space or impeding supernumerary teeth). However, in some cases there is no obvious cause. Treatment of these cases might be easier if we fully understood the mechanism of eruption itself. Unfortunately, the precise process of generating the eruptive force for teeth has...