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Biomedical subjects

R J Billings

Publications and source records attributed to R J Billings.

At least 19 recordsLinked to original sources
PubMed1996

Xerostomia and associated factors in a community-dwelling adult population.

Xerostomia is the subjective sensation of dry mouth. Estimates on the occurrence of xerostomia in community-dwelling adults have ranged from 10% among persons over age 50 to 40% for persons over age 65. Virtually no data are available for persons under age 50. To begin to establish a database on the occurrence of xerostomia and factors associated with it, a cross-sectional assessment of self-reported symptoms and salivary function was conducted across a broad age-range of generally healthy community-dwelling adults. A convenience sample of 710 adults who ranged from 19 to 88 years of age was drawn from various sources in the greater-Rochester, New York area. Study volunteers were administered a standardized questionnaire on general and oral health, which included questions on the symptoms of xerostomia, and were provided an oral screening examination, which included measurement of unstimulated and stimulated whole saliva flow rates. Overall, the observed prevalence of xerostomia was 24% among females and 18% among males. While xerostomia was more commonly observed in women than men, this association was only clear after age 50. Xerostomia was associated with: use of medications with hyposalivatory side-effects; difficulty with dry foods; cracked lips; dry eyes; difficulty swallowing; and, among males, current cigarette smoking. Results indicated a tendency for salivary flow rates to be lower for older persons, particularly the stimulated flow rate. There was a tendency in the younger cohorts for flow rates to be lower among individuals who reported sensation of dry mouth than among those who did not. This tendency was not apparent among older persons, suggesting that younger persons may be more likely to experience symptoms of oral dryness when salivary flow was low while older persons may relate symptoms of dry mouth to a more complex constellation of factors where salivary flow is only one component. These findings need to be examined further.

Adult↗
PubMed1995

Association of free arginine and lysine concentrations in human parotid saliva with caries experience.

We determined the free-amino acid content of stimulated parotid (ductal) saliva from two groups of adult subjects whose caries experiences were markedly different. The levels of free arginine and free lysine in the parotid saliva of caries-free adults were significantly higher than those found in the parotid saliva of individuals with a history of dental decay. There was no correlation, however, between the levels of these amino acids and the DMFS score within the caries-susceptible groups. Microbial catabolism of dibasic amino acids contributes to the neutralization of plaque acids and may partially account for the higher resting plaque pH observed in caries-free subjects. Alternatively, the elevations observed in free levels of arginine and lysine may reflect a systemic alteration in amino acid metabolism which is common to the caries-free group of subjects.

Adolescent↗
PubMed1993

Future directions for root caries research.

Interest among researchers in the diagnosis, aetiology, prevention, and treatment of root caries has increased substantially over the past two decades. However, there are some fundamental problems impeding the advancement of the field which remain to be addressed and resolved. A universally acceptable definition of root caries is not yet available. The relationship of root caries to coronal caries has not been established. The underlying disease process is still not clearly understood. The optimal utilisation of preventive/therapeutic agents for the treatment or prevention of root caries has not been determined. New treatment materials and preventive agents have not yet been tested in controlled clinical trials. These are a few of the issues and problems which we address in this paper.

Humans↗
PubMed1993

Caries risk assessment by a cross-sectional discrimination model.

Although the prevalence of dental caries is continuing to decline, it still affects a majority of the US population and can be a serious problem for those afflicted. The objective of this project was to develop and perfect a model for assessment of risk of dental caries onset in children. In the first study, reported herein, a set of clinical, microbiological, biochemical, and socio-demographic variables was identified that distinguished, with an acceptable level of sensitivity and specificity, between children who had no previous caries experience and children who had high caries levels. A total of 313 children--age 12-15 years, 140 from a fluoridated community and 173 from a fluoride-deficient community--was selected on the basis of previous caries experience, either zero DMFS or high DMFS (> or = 6 in the fluoridated or > or = 8 in the fluoride-deficient community). Clinical exams for DMFS, dental fluorosis, and plaque were conducted. Stimulated whole saliva was collected for analysis of mutans streptococci, lactobacilli, total viable flora, and fluoride concentration. A questionnaire was used for collection of demographic data as well as information on prior fluoride exposure, dietary habits, and oral hygiene practices. By means of discriminant analyses, with use of seven key clinical and laboratory variables, it was possible for zero-DMFS subjects to e classified correctly (specificity) in 77.6% of cases in the fluoridated community and in 86.1% of cases in the fluoride-deficient community. High-caries subjects were classified as such (sensitivity) in 79.3% and 88.1% of cases, respectively.

Adolescent↗
PubMed1993

Caries risk assessment in a longitudinal discrimination study.

Our objective was to develop and perfect a model for the assessment of risk of dental caries onset in children. Even though dental caries prevalence in children is continuing to decline, there is still a significant minority for whom it is a problem. In this study, we sought to ascertain whether a set of variables selected in a previous cross-sectional study could be used to differentiate between caries-free six-year-olds who would or would not subsequently present with clinically-detectable caries. A total of 472 caries-free six-year-olds--286 from a fluoridated community and 186 from a fluoride-deficient community--was selected. Clinical examinations for DMFS, dental fluorosis, and plaque were conducted. Stimulated whole saliva was collected for analysis of mutants streptococci, lactobacilli, total viable flora, and fluoride, calcium, and phosphate concentrations. A questionnaire was used for collection of demographic data as well as information on prior fluoride exposure, dietary habits, and oral hygiene practices. By means of linear discriminant analyses, it was possible to predict correctly which children would develop caries within six to 12 months (sensitivity) in 82.8% of cases and which children would not develop caries during that period (specificity) in 82.4% of cases.

Apatites↗
PubMed1993

An epidemiologic perspective of saliva flow rates as indicators of susceptibility to oral disease.

Catastrophic hyposalivation significantly increases susceptibility to dental caries in dentate individuals and may cause the expression or exacerbation of other oral diseases/disorders as well. The effect of subcatastrophic hyposalivation on susceptibility to caries or other diseases/disorders is less well understood. The aim of this study (part of a larger study on the prevalence of hyposalivation) was to determine the prevalence and to measure the association of oral pathologic conditions with unstimulated and stimulated whole saliva flow rates. Only 6.3% of all study participants had significantly diminished unstimulated (< 0.05 ml/min) and stimulated (< 0.50 ml/min) saliva flow rates. A total of 15 individuals were encountered with oral pathologic lesions and none of these lesions were associated with hyposalivation. Although the prevalence of coronal caries, root surface caries, abrasion, and erosion tended to increase as salivary flow decreased, when the effect of age was considered no significant differences were present. These data suggest that low saliva flow rates alone, at least from an epidemiologic perspective, do not have a clinically relevant effect on susceptibility to oral diseases/disorders.

Adult↗
PubMed1991

Associations of microbiological factors and plaque index with caries prevalence and water fluoridation status.

Plaque indices, numbers of mutans streptococci, lactobacilli and total viable flora in plaque and saliva were assessed as part of a large-scale cross-sectional study designed to determine the factors that are associated with high caries activity in children. Subjects, 12 to 15 years old, residing in areas where the water supplies were either fluoridated (n = 140) or fluoride-deficient (n = 173) were studied. Mutans streptococci and lactobacilli numbers in saliva were positively correlated with plaque index. Plaque indices were significantly higher in the high-caries group than in the zero-caries group of the fluoride-deficient community. In the fluoridated community, there was no difference in the plaque index between the zero- or high-caries groups. In each community, pooled dental plaque and saliva harbored fewer mutans streptococci and lactobacilli in the zero-caries than the high-caries group. Greater numbers of mutans streptococci were found in the dental plaque and saliva of the zero-caries subjects in the fluoridated community than in the fluoride-deficient community, suggesting that a greater caries challenge can coexist with zero-caries status in the fluoridated community.

Adolescent↗
PubMed1991

Use of an intra-oral model to evaluate 0.05% sodium fluoride mouthrinse in radiation-induced hyposalivation.

The present study was undertaken to evaluate the effect of a twice-daily topical application of a 0.05% NaF mouthrinse on de- and remineralization in the oral cavities of subjects suffering from radiation-induced hyposalivation. Six subjects each wore a bonded intra-oral appliance containing a sound and a demineralized human enamel slab for four weeks. During that period, the subjects used 0.05% NaF rinses, twice daily, instead of the 1.1% NaF gel that had previously been a part of their preventive regimen. Salivary flow rates, plaque pH profiles following a 10% sucrose rinse, S. mutans and lactobacillus counts, fluoride clearance, and enamel microhardness were determined during the study. Sound enamel samples displayed no evidence of demineralization, and the previously demineralized enamel showed remineralization in the outer 50 microns in three of the six subjects. The results suggest that a twice-daily oral rinse with 0.05% NaF can prevent demineralization and enhance remineralization in subjects with radiation-induced hyposalivation.

Bacteria↗
PubMed1989

Rerandomization tests for analyzing correlated data from dental studies.

Dental research studies often produce relatively small data sets in which observations are serially or spatially correlated. Rerandomization tests are presented as alternatives to analysis of variance and multivariate analysis for assessing group differences using such data. Rerandomization tests are particularly useful when the investigator is unwilling to make strong assumptions about the nature of the serial correlation or the distribution of the data. Two examples are discussed that demonstrate these techniques.

Data Interpretation, Statistical↗
PubMed1989

The origin of the occipital lambda wave in man.

The relationship between occipital lambda waves, saccadic eye movements, and pattern reversal visual evoked potentials (VEPs) has been investigated in 23 normal control subjects and 24 patients with suspected multiple sclerosis (MS). The VEP, electro-oculogram (EOG) and lambda waves were recorded similarly in both groups. The lambda waves were averaged, using pre-defined points in the saccadic eye movements for synchronisation. A comparison was made between the VEP and lambda waves recorded in patients with delayed VEP and in patients with a 'W'-shaped VEP morphology. In the normal subjects, the VEP and lambda waves recorded in response to full-field stimulation were compared with those recorded using a stimulus devoid of foveal pattern. In addition, the lambda waves from the control group were averaged according to different criteria, dependent on the presence of a secondary, corrective saccade. A hypothesis for the generation and transmission of lambda waves has been established. It is proposed that there are 2 different types of lambda wave. The first is generated as a result of retinal afferent activity due to the return of normal visual sensibility in the peripheral visual field, following its suppression during the saccadic eye movement. This activity is transmitted via the faster conducting Y fibres in the optic nerve. The second lambda wave results from the retinal afferent volley caused by the release of suppression of the central visual field, conducted via the slower X fibres in the optic nerve.

Adolescent↗
PubMed1989

The origin of the initial negative component of the averaged lambda potential recorded from midline electrodes.

There are differences in morphology and latency between averaged lambda waves and averaged pattern reversal visual evoked potentials (VEPs). Averaging of lambda potentials recorded from Oz-Fz, Oz-Cz and Oz-Pz was synchronised from various points in the electro-oculogram (EOG) wave form, during targeted saccadic eye movements across a checkerboard which was subsequently used for pattern reversal VEPs. EOG and blinks (electrical and infra-red) were recorded and also averaged from eye movements performed in darkness. The initial, prominent, negative component in the averaged lambda wave was shown to be due to eye blink artefact caused by a partial lowering of the upper lid, each blink coinciding with every saccadic eye movement which elicited a lambda wave when scanning the pattern but not when the eye moved in darkness.

Adult↗
PubMed1988

Retention of topical fluoride in the mouths of xerostomic subjects.

The total fluoride concentration in unstimulated whole saliva was measured before and at selected intervals after a self-applied 1.1% neutral NaF topical fluoride gel or use of a 0.05% neutral NaF fluoride mouthrinse in both normal individuals and patients with radiation-induced xerostomia. As expected, the gel resulted in higher peak fluoride values than the rinse and was retained in the mouth for longer periods of time in both groups. The xerostomic group expressed a mean oral fluoride concentration of 575 micrograms fluoride per gram of saliva within 1 min after the gel application and 150 micrograms/g following use of the mouthrinse, whereas the normal group exhibited peak concentrations of 112 and 71 micrograms/g, respectively, within 1 min after the same two treatments. The initial high levels of fluoride observed in normal subjects following the gel application decreased rapidly to less than 1 microgram/g within 2 h, whereas fluoride levels in the xerostomic subjects remained elevated above 12 micrograms/g for longer than 2 h. Similarly, following use of the mouthrinse, normal subjects' saliva fluoride levels decreased to less than 1 microgram/g within 1 h, whereas xerostomic subjects' saliva fluoride levels remained above 4 micrograms/g for longer than 2 h.

Adult↗
PubMed1986

Assessment of the effect of chemotherapy and radiotherapy on the auditory function of children with cancer.

Forty children with malignant disease underwent full audiological assessment with pure tone audiometry, tympanometry and measurement of brain stem auditory evoked potentials in an attempt to detect auditory dysfunction resulting from treatment. Significant auditory dysfunction was observed in 8 children. Three children with evidence of a conductive or sensorineural deafness on pure tone audiometry had normal brain stem evoked potentials. One child with a high tone hearing loss and 4 children with no detectable hearing loss on audiometry showed significant differences in the interaural interpeak latencies of selected brain stem auditory evoked potentials. In 2 children these abnormalities had resolved on subsequent testing, 2 had evidence of persistent retrocochlear dysfunction and the remaining child died prior to further evaluation. Routine measurement of brain stem auditory evoked potentials is probably not necessary for the majority of children undergoing treatment for cancer, although such measurements are of value when differentiation between cochlear and retrocochlear damage is required.

Acoustic Impedance Tests↗
PubMed1986

Quantitative comparisons of potentially cariogenic microorganisms cultured from noncarious and carious root and coronal tooth surfaces.

Potentially cariogenic microorganisms cultured from noncarious and carious root and coronal (enamel) surfaces were quantitatively compared in patients 22 to 84 years of age (mean, 52 years). We collected 150 plaque specimens from 26 in situ teeth with initial root lesions and from 25 extracted teeth with advanced root lesions. The frequencies of isolation of Streptococcus mutans, Actinomyces viscosus, and Lactobacillus spp. were, respectively, 94, 72, and 51% at the noncarious root site; 98, 71, and 54% at the root lesion; 84, 61, and 44% at the noncarious enamel site; and 100, 66, and 90% at the enamel lesion. The streptococci made up the largest mean proportion of the total anaerobic cultivable microflora, ranging from 31.2% at the noncarious enamel site to 37.6% at the root lesion, while S. mutans varied between 18% at the noncarious enamel and root surfaces and approximately 24% at both the enamel and root lesions. The proportion of actinomyces ranged from 12.3% at the root lesion to 23.6% at the noncarious root site, while A. viscosus varied from 7.8% at the root lesion to 15.1% at the noncarious root site. The largest mean proportion of lactobacilli (4.2%) was recovered at the enamel lesion site. Proportions of Candida spp. made up less than 0.1% at all sites. Proportions of microorganisms did not differ significantly between noncarious enamel and root sites, but the noncarious coronal and root sites had higher (P less than 0.05) proportions of actinomyces than did the root lesion. Also, enamel lesions had a greater (P less than 0.05) percentage of Lactobacillus spp. than did root lesions. The number of streptococci recovered from the root lesion was greater (P less than 0.01) than the number of actinomyces at the same site. S. mutans was recovered from initial root lesions in greater numbers (P less than 0.001) than were actinomyces and lactobacilli. The number of S. mutans recovered at the initial root lesions was greater (P less than 0.01) than that recovered from the advanced root lesions.

Actinomyces↗
PubMed1981

Automatic detection, measurement and documentation of the visual evoked potential using a commercial microprocessor-equipped averager.

A program has been developed, using a Datalabs Unimac 4000B wave form analyser and microprocessor, which automatically detects and measures the averaged VEP, compares it with the data obtained from normal subjects and prints the results in a report-quality format. The minimum additional requirements are a printer and the Datalabs 2 kbyte non-volatile program store. The method correctly identifies the relevant peak and trough (N2 and P2) in 84.2% of potentials from a patient population, but the design of the program allows the operator to override the values determined. The modifications appear in the results printed on completion of the measurement sequence. A useful, adaptable and time saving application of fixed function microprocessor has been developed which provides latency, amplitude and normality information for VEPs.

Computers↗