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Biomedical subjects

D K Whittaker

Publications and source records attributed to D K Whittaker.

At least 37 records · Page 2Linked to original sources
PubMed1990

Use of benzidine for histological demonstration of haemoglobin in human bite marks.

Macroscopic evidence of bruising from human bite marks may be inconclusive and routine histochemical methods of showing extravasated erythrocytes can be unreliable. Leuco patent blue staining, for the presence of peroxidase, Amido black B, a tinctorial staining method for haemoglobin, Perls's reaction for ferric iron (haemosiderin), Masson-Fontana for melanin, Masson's trichrome, a connective tissue strain, and the benzidine reaction for haemoglobin peroxidase were carried out in three forensic cases and one experimental case. A modified benzidine method was the most reliable indicator of haemoglobin activity, especially where dispersion into extra-cellular tissues had occurred. The resilience of the erythrocyte peroxidase enzyme to temperature changes and fixation supports the concept of a "pseudo-peroxidase" in those cells. It is concluded that free haemoglobin from bite marks, or indeed other forms of blunt trauma, may best be shown by the benzidine reaction and that exemption certificates for use of this prohibited substance may be worth pursuing.

Aged↗
PubMed1990

Principles of forensic dentistry: 1. Identification procedures.

From time to time the general dental practitioner may become involved in forensic cases, when he or she will need to be aware of the general principles involved and the increasing variety of modern techniques available. This two-part article reviews those principles and techniques. In Part 1 procedures used in identifying bodies are discussed. Part 2 will concentrate on non-accidental injury to children and analysis of bite marks, and discuss archaeological investigations.

Age Determination by Teeth↗
PubMed1990

Principles of forensic dentistry: 2. Non-accidental injury, bite marks and archaeology.

From time to time the general dental practitioner may become involved in forensic cases, when he or she will need to be aware of the general principles involved and the increasing variety of modern techniques available. This two-part article reviews those principles and techniques. In Part 1 the principal procedures used in identifying bodies were discussed. Part 2 now reviews the role of the forensic dentist with respect to non-accidental injury to children, analysis of bite marks, and archaeological investigations.

Bites, Human↗
PubMed1988

Suitability of human, bovine, equine, and ovine tooth enamel for studies of artificial bacterial carious lesions.

The progress of artificial caries-like lesions created in human, bovine, equine, and ovine enamel has been studied. Lesions were produced by exposure to an acid gel system or by 5-day exposure to a sequential batch culture technique using Streptococcus mutans NCTC 10832. Longitudinal ground sections were prepared. The lesions were of similar appearance in all species when examined in polarized light. The depth in human enamel was approximately half that in the animal species. Microradiography confirmed subsurface demineralization in all four species. Similar depth ratios were seen in the scanning electron microscope, but there were structural differences between lesions in human and animal teeth. Lesions in bovine teeth were more like those in human, but lesions in equine and ovine teeth were markedly different. Substitution of these animal enamels for human enamel in caries experiments demands that these differences be taken into account. Scanning electron microscopy is capable of resolving features in artificial caries lesions which cannot be differentiated by polarized light techniques. The latter will demonstrate generalized mineral loss, but scanning electron microscopy is required to characterize the sites of mineral loss.

Adult↗
PubMed1987

Patterns of approximal wear in cheek teeth of a Romano-British population.

The approximal surfaces of premolars and molars of 376 adult British-Romano skulls were examined for wear facets. The type of wear was designated as convex, concave, sigmoid, or flat, and the degree was categorised on a three-point scale. Concave wear facets were more frequently seen in the older age groups, but the type of wear was similar on right and left sides. Taking all teeth together or as individual tooth types, concave wear was significantly more likely on mesial rather than distal surfaces. The degree of wear was age related and similar on right and left sides in both males and females. It is suggested that the distribution of concave facets may be related to movements between adjacent teeth.

Bicuspid↗
PubMed1987

The influence of enamel prism orientation on leakage of resin-bonded restorations.

A new method is described for the quantification of leakage between etched enamel and restorative resin. A significant correlation was demonstrated between the plane of enamel section prior to etching and subsequent leakage. It is suggested that these findings will be of value in the design of cavities for use with the acid-etch technique; when possible, enamel should be prepared to expose prisms transversely prior to etching and bonding.

Acid Etching, Dental↗
PubMed1985

Quantitative assessment of tooth wear, alveolar-crest height and continuing eruption in a Romano-British population.

Although measurements from cement-enamel junction (CEJ) to alveolar crest (AC) have been used in assessing changes in alveolar-crest height as age or chronic inflammatory periodontal disease (CIPD) progresses, there is evidence from ancient populations that the position of AC remains almost constant throughout life and continuing eruption to compensate for attrition may explain why CEJ-AC measurements increase with age. Measurements of occlusal attrition and relationship of CEJ to AC were made on the cheek teeth of 500 Romano-British skulls by direct measurement or by reference to the fixed line of the inferior alveolar canal (IAC) on radiographs. Direct measurements indicated that there were usually no statistical differences between the vertical amounts of tooth substance lost by attrition and the change in the distance CEJ-AC as age progressed. Measurements on radiographs showed that posterior teeth continued to erupt to compensate for attrition and the AC remained static as age progressed. Bone deposition at the AC was seen in the majority of ground sections. Thus tooth wear appears to be compensated by continuing movement of teeth in an occlusal direction. The position of the AC remained almost constant throughout life; AC bone lost by CIPD seemed to be replaced during continuing tooth eruption.

Age Factors↗
PubMed1985

Healing of specialized tongue epithelium following cryosurgery.

Although cryosurgery of oral tissues has been extensively studied, there is little information concerning healing and repapillation of the dorsum of the tongue. Using light, transmission, and scanning electron microscopy, an investigation of the sequence of reformation of papillae was carried out in the hamster. Four days postoperatively there was mitotic activity and cell migration at the periphery of the wound. At the edge of the ulcer there were partially damaged tongue papillae with evidence of recovery. Damaged papillae had regenerated completely within 2 weeks. In the central ulcerated area, epithelium healed by migration and, within this new epithelium, tongue papillae commenced to form by a process similar to that seen in the fetal tongue. Repapillation of the central area of the lesion was complete 6 weeks after operation, leaving minimal scarring. The details of these processes are described.

Animals↗
PubMed1985

Regeneration of muscle following cryosurgery of the tongue.

Regeneration of muscle following low-temperature destruction of tissue has not been extensively studied. Using light and transmission electron microscopy an investigation of this phenomenon was made in hamster tongue. Healing commenced 1 week after the operation and was of the continuous regeneration type in the least damaged muscle fibers. Healing was of the discontinuous or embryonic type in severely damaged muscle and myoblasts formed either within old intact endomysial tubes or separate from them. Healing with minimal scarring was well advanced 6 weeks after the operation.

Animals↗
PubMed1985

Tooth loss, attrition and temporomandibular joint changes in a Romano-British population.

Mandibular condyles and temporal fossae were studied in a large Romano-British collection of skulls. The size and shape of the condyles differed from those in previous populations studied. Changes in form or shape of the condyles were age-related and could be correlated to the number of teeth lost on the same side and on the contralateral side. No statistically significant correlations were seen between attrition and condylar form and surface change.

Adolescent↗
PubMed1984

Phosphoglucomutase isoenzymes in human teeth.

Powdered dentine samples were prepared from fresh teeth and teeth allowed to putrefy for up to 90 days. In some samples dentine only was included, whereas in others dentine plus pulp remnants were used. Extracts of the powders were tested for phosphoglucomutase activity by starch gel electrophoresis and PGM typing was carried out. Fresh teeth showed activity in at least 50% of cases as did putrefied dentine plus pulp remnants. Putrefied dentine alone showed minimal activity. The method may be useful for identification procedures using fragments of teeth.

Blood Grouping and Crossmatching↗
PubMed1984

Mutilated teeth.

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Adolescent↗
PubMed1984

Mechanisms of tissue destruction following cryosurgery.

Destruction of diseased tissue in situ by means of freezing is well established in many branches of surgery. The tissues are apparently unaltered at thaw but progressive necrosis ensues. There is controversy as to whether tissue death is principally due to the direct effects of freezing or to subsequent ischaemia. Studies at the ultrastructural level show that ice-crystals are formed within the cells during cryosurgery, that resultant cell damage is osmotic rather than mechanical and that microcirculatory changes are secondary in terms of the chronological development of tissue necrosis.

Animals↗
PubMed1982

Structural variations in the surface zone of human tooth enamel observed by scanning electron microscopy.

The surface zone of human deciduous and permanent enamel was examined following sectioning, polishing and etching. Three main types of surface were where prisms reached the surface, where the prisms were not discernible and those formed by a complex of both types. The aprismatic layers were measured and the percentage of teeth with varying thicknesses at different sample sites was calculated. Thickness of surface aprismatic enamel varied between different tooth types, tooth surfaces and between deciduous and permanent teeth. It is likely that variations in the structure of surface enamel affect caries susceptibility and results of etching and bonding techniques.

Adolescent↗