PubMed Health⌕ Search

Biomedical subjects

J W Rippin

Publications and source records attributed to J W Rippin.

At least 19 recordsLinked to original sources
PubMed1992

Intra-oral salivary gland tumours in the West Midlands.

Intra-oral salivary gland tumours reported from the West Midlands over the years 1975-88 were examined as to a number of epidemiological variables; the question as to their increasing incidence was also addressed. The findings were largely in agreement with those of most previous authors in that most of the tumours occurred in the palate, but whereas most of these were benign, a large proportion of those in other sites were malignant. However, firm conclusions are difficult to draw since there is much disagreement over reporting criteria. An international workshop and comprehensive tumour registries are required in order to determine more accurate data and conclusions. Similar cooperation is necessary in order to substantiate or refute the suggestion that the incidence of salivary gland tumours is increasing.

Adenocarcinoma↗
PubMed1992

Odontogenic keratocyst in an infant.

Odontogenic keratocysts occur as solitary lesions or in association with the basal cell naevus syndrome (BCNS), and have been documented in the age range 5 to 83 years. A rare case of an odontogenic keratocyst in a one-year-old girl is presented. Its characteristic tendency to recur, and its association with BCNS present important clinical implications.

Basal Cell Nevus Syndrome↗
PubMed1992

Effect of precurving endosonic files on the amount of debris and smear layer remaining in curved root canals.

Endosonic files are prone to constraint; this reduces their efficiency, particularly in the apical third and in curved root canals. Precurving the file may reduce constraint, thereby improving the file's ability to debride. This investigation was undertaken to compare both straight and precurved endosonic files as to debris and smear layer removal. Thirty-six curved root canals were randomly allocated into six groups. Each group was prepared using a step-down technique, then instrumented with either a straight or precurved endosonic file of size 15, 20, or 25. The tooth roots were split and examined under the scanning electron microscope. Blind examinations were made for debris and smear layer removal and evaluation scores were analyzed using a log linear approach. The root canals instrumented with the precurved files had a significantly lower debris score than those prepared with straight files. Precurving did not affect smear layer removal. In conclusion, precurving of files decreased the amount of debris but did not affect smear layer removal.

Dental Cavity Preparation↗
PubMed1991

A study of the relationship among pulpal response, microbial microleakage, and particle heterogeneity in a glass-ionomer-base material.

This investigation was designed to study the pulpal responses to glass-ionomer base materials that differ in particle size distribution. The study was carried out according to the BSI (1980) recommendations for testing restorative materials in vivo. The base materials caused more pulpal inflammation than the control material, Kalzinol, although by an indirect mechanism. A significant association was demonstrated in the statistical model between bacterial presence within the experimental cavity and pulpal inflammation. The type of restorative material has no direct association with the degree of inflammation, although the model suggests that it exerts an indirect influence via its antibacterial properties, and hence its influence on microbial microleakage. The base material, with a heterogeneous particle distribution, was associated with greater bacterial microleakage. Particle size distribution, therefore, has some effect upon bacterial microleakage, but, because of its complex effect upon several physical properties of materials, further studies are indicated.

Animals↗
PubMed1991

Pulpal response to two semihydrous glass ionomer luting cements.

This study compared the pulpal responses to two innovative semihydrous glass ionomer luting cements (STA and ZIN) with those previously obtained for a conventional anhydrous glass ionomer luting cement, Aquacem. ZIN contained zinc oxide in the formulation. The study was conducted according to the BSI (1989) recommendations for testing restorative materials in vivo. ZIN was associated with minimal pulpal changes and microbial microleakage, and differed little from the control material, Kalzinol. The pulpal response to STA was similar to that observed for Aquacem, but was associated with less microbial microleakage. The statistical model demonstrated a significant association between bacterial presence within the experimental cavity and pulpal inflammation. The closer that bacteria were to the pulp, the more severe was the ensuing inflammation.

Analysis of Variance↗
PubMed1989

Pulpal response to an anhydrous glass ionomer luting cement.

This investigation was designed to study the pulpal responses to Aquacem, an anhydrous glass ionomer luting cement, and to compare the results with those previously obtained for a conventional glass ionomer luting cement, Chembond. The study was carried out according to the BSI (1980) recommendations for testing restorative materials in vivo. Aquacem caused more pulpal inflammation than the control material, Kalzinol, though by an indirect mechanism. The statistical model demonstrated a significant association between bacterial presence within the experimental cavity and pulpal inflammation. The type of restorative material has no direct association with the degree of inflammation, but the model suggests that it exerts an indirect influence via its antibacterial properties and hence its influence on microbial microleakage.

Animals↗
PubMed1989

Analysis of cell cycle subpopulations from cytometric data.

As a result of experimental error, measurements of the DNA content of cells from proliferating populations give rise to histograms in which the G1-phase, S-phase and G2-phase distributions overlap. A new method for distinguishing these subpopulations is proposed, based on a model in which the S-phase subpopulation is made up of a number of uniformly overlapping log-normal curves, whose composite has a rectangular central part and sloping ends. The ratio between certain parameters of the slopes and the height of the rectangle is shown to be closely related to the degree of overlap of the constituents by a defined cubic polynomial. It is then possible to calculate the numbers of cells in each of the three phases of the cell cycle, even when only a few hundred cells have been measured.

Animals↗
PubMed1988

The post-operative maxillary cyst. Experience with 23 cases.

23 cases, diagnosed as post-operative maxillary cyst, from outside Japan are described. Clinical, radiographic and histopathological features are not dissimilar to those cases reported from Japan, and various parameters have been found to be helpful in diagnosis. This lesion is more common outside Japan than previously suggested, and this is probably largely due to faulty diagnosis.

Adult↗
PubMed1988

Medical science and the patient.

Classification is necessary to most forms of thought, and the scientific method requires particular refinement of this process in order to formulate its laws. But there is nothing fundamental about any classification; its categories are chosen for a particular purpose only, and often at least some of the subjects do not fall readily into any class. Furthermore, since only few of an individual's characteristics are used as classifying attributes, individuals themselves become submerged in the class, and their individuality lost in the scientific laws that arise therefrom. Desiderata of science and uniqueness are therefore opposed--and they are irreconcilable because absolute knowledge is either non-existent or unattainable. Thus, the decision as to whether an individual patient is healthy or diseased must be made on the basis of diagnostic laws which, as far as the individual is concerned, are inaccurate and may turn out to be spurious or even meaningless. These laws are therefore only guide-lines which must be 're-individuated' in clinical practice. In essence, the individual's health depends on the individual's biology.

Classification↗
PubMed1987

The odontogenic keratocyst and its occurrence in the nevoid basal cell carcinoma syndrome.

There are histologic differences between odontogenic keratocysts occurring in the basal cell carcinoma syndrome (NBCCS) and as single lesions in otherwise healthy persons. This study identifies certain differences in age, gender, and site between the two groups. The age at removal of the first keratocyst is significantly lower in the syndrome group. On more thorough examination, patients with multiple keratocysts (excluding recurrences) are found to have other features of NBCCS. The term multiple cysts refers to the lifetime history of the patient and does not necessarily imply that more than one cyst is present at any one time.

Adolescent↗
PubMed1987

A comparative histological study of odontogenic keratocysts in basal cell naevus syndrome and control patients.

164 odontogenic keratocysts from 60 patients with the basal cell naevus syndrome were compared with a similar number of single keratocysts matched for age and site. Significant differences between the two groups were found in the numbers of satellite cysts, solid islands of epithelial proliferation and odontogenic rests within the capsule, and in the numbers of mitotic figures in the epithelium lining the main cavity. An index of activity derived from these parameters suggests a greater growth potential in syndrome cysts; in addition, the patterns of association of the features support the theory that the odontogenic rests give rise to satellite cysts.

Adolescent↗
PubMed1987

A comparative study of the clinical and histological features of recurrent and non-recurrent odontogenic keratocysts.

The clinical features of 44 recurrent odontogenic keratocysts were compared with those of 228 single non-recurrent keratocysts which had been followed for 5 or more years. Histological comparisons were made with 44 non-recurrent cysts matched for age, sex and site. There were no significant differences in the age, sex and site between patients with recurrent and non-recurrent cysts. There were no significant histological differences except for a greater amount of inflammation in the non-recurrent cysts. It is suggested that operative factors have a major influence on the likelihood of recurrence.

Adolescent↗
PubMed1987

The basal cell naevus syndrome.

The basal cell naevus syndrome, classically described as a triad of multiple basal cell carcinomas, odontogenic keratocysts of the jaws and skeletal anomalies, is well known by oral and plastic surgeons and dermatologists. This paper describes the clinical features in a series of 60 patients, and highlights some problems of diagnosis and management.

Adolescent↗