PubMed Health⌕ Search

Biomedical subjects

L M Macpherson

Publications and source records attributed to L M Macpherson.

At least 19 recordsLinked to original sources
PubMed2001

The effect on human salivary fluoride concentration of consuming fluoridated salt-containing baked food items.

Salt fluoridation is recognised world-wide as a proven and viable alternative means of consumer choice-related, community-based fluoridation where water fluoridation is either technically or politically impossible. However, as most salt consumed is contained within cooked food products, rather than sprinkled over prepared food at the table, the purpose of this study was to investigate the effects on salivary fluoride concentration of consuming baked food products prepared with 250 and 350 ppm fluoridated salt (as KF). Six food items were baked with (a) normal non-fluoridated salt, (b) 250 mg F/kg salt and (c) 350 mg F/kg salt. Eleven adult volunteers consumed these foodstuffs on separate occasions and salivary samples were collected for fluoride analyses before and at various time points (1-30 min) after eating. For most foodstuffs, small but significant increases in salivary fluoride concentration occurred for at least 5 min after ingestion of the fluoridated salt-containing items. Salivary fluoride concentrations peaked 1 or 2 min after eating, with highest values for the six test foods ranging from 0.16 to 0.25 ppm F, and from 0.18 to 0.44 ppm F for the 250 and 350 mg F/kg salt products, respectively. In all cases, salivary fluoride concentrations had returned to baseline by 20 min. The clinical significance of such small, short-term increases in salivary fluoride is uncertain, but the findings suggest that a more frequent intake of foods with fluoridated salt substituted for normal salt could help sustain slightly elevated salivary fluoride concentrations for more prolonged periods of the day, and might thus potentiate the cariostatic effects of saliva on tooth mineral.

Adult↗
PubMed2000

Comparison of a conventional and modified tooth stain index.

OBJECTIVES: To evaluate a modified tooth stain index and determine the effect of dietary factors on stain formation. METHODS: At baseline, 182 adult volunteers were given a full oral prophylaxis followed by stain assessment using a modification of the Lobene index. This involved assigning separate scores to the mesial (M) and distal (D) sites of each tooth, in addition to the standard gingival area (G) and tooth body (B). For each site, stain intensity and areas were scored. The sum of (intensity X area) scores was calculated for all sites (GBMD-value) and for the gingival and body sites only (GB-value). The subjects used a standard abrasive dentifrice and a soft toothbrush for 6 weeks. RESULTS: Stain was reassessed and the average increase in GBMD-value was 20.9 (sd=9.9) (buccal aspect) and 29.9 (sd=18.0) (lingual aspect). The corresponding GB-values were 4.4 (sd=4.8) and 12.5 (sd=10.2). The coefficients of variation of the GBMD index values were consistently lower than those of the GB values. Smoking and tea-drinking were found to be the only significant (p<0.001) factors investigated for stain formation. CONCLUSIONS: It is concluded that the modified index may well be advantageous to its conventional counterpart because sites with most visible stain are assessed separately and because it may also offer higher discriminatory power due to a lower coefficient of variation.

Adolescent↗
PubMed2000

The role of the general dental practitioner in detection and prevention of oral cancer: a review of the literature.

Over the last two decades little progress appears to have been made in reducing the incidence and number of deaths associated with oral cancer. The most recently available Scottish data indicate a steady rise in both incidence of, and mortality rates from, tongue and 'mouth' cancer, supporting previous observations of a steady rise in the incidence of oral cancer since the mid 1970s. Very little improvement in 5-year survival rates for oral cancer has been observed in England and Wales and, over the last 30 years, survival rates in Scotland have actually declined. Although many dentists are committed to examining the mouth for oral cancer, the majority still feel uncomfortable with involvement in patient education. Clearly scope exists for dental practitioners to improve patient awareness of both oral cancer itself and the risk factors associated with the disease. Dental teams should be aware of the opportunities within dental practice to contribute to preventive initiatives--such as smoking cessation.

Adult↗
PubMed2000

A survey of Scottish primary care dental practitioners' oral cancer-related practices and training requirements.

OBJECTIVE: The study sought to investigate current examination habits and preventive practices of Scottish dental primary care professionals, with respect to oral cancer, and to determine any training needs of these practitioners in relation to the disease. BASIC RESEARCH DESIGN: A questionnaire was sent to a random sample of 331 general dental practitioners and community dental officers throughout Scotland, achieving an overall response rate of 68%. MAIN OUTCOME MEASURES: The study investigated examination and health promotion practices in relation to oral cancer. Confidence in, and barriers to, participating in these activities were studied, and information sought both on past training and future education needs regarding oral cancer. RESULTS: Although 58% of respondents reported examining regularly for signs of oral cancer in those aged >16 years, 63% indicated they felt less than confident in detecting oral cancer, with only 43% expressing confidence about discussing suspicious findings with patients. Practitioners were well aware of the importance of smoking and alcohol as risk factors, but had mixed views on the health-promoting role of the dentist regarding these issues. Furthermore, while only 3% reported training on these topics, over half expressed a desire to develop appropriate counselling skills. Overall, 87% and 79% of respondents wanted further training in oral cancer detection and prevention, respectively. CONCLUSION: The study indicated a need for continuing education programmes for dental primary care practitioners in oral cancer-related activities. Postgraduate education, utilising a variety of media formats, should aim to improve diagnostic skills and seek to increase practitioners' participation in both smoking and alcohol counselling.

Alcohol Drinking↗
PubMed1999

Effect of fluoridated salt intake in infancy: a blind caries and fluorosis study in 8th grade Hungarian pupils.

UNLABELLED: Salt fluoridation is effective at inhibiting caries, but fluorosis prevalence data are deficient. OBJECTIVES: The purpose was to undertake a blind study of caries and tooth mottling in 8th grade school pupils from south-east Hungary who had resided (test) or not resided (control), until November 1985, in a 350 ppm F-/kg domestic salt-fluoridated area during their early years of life. METHODS: In Szeged, blind clinical caries and anterior tooth mottling scoring (+10% repeats) of 49 previously salt-fluoridated (mean age 14.14 years) and 59 non-salt-fluoridated subjects (mean age 14.08 years) were undertaken by one examiner, in June 1997. In addition, radiographic and photographic recordings were taken. In Glasgow, four dental and two lay staff scored the projected 35 mm colour transparencies (+10% repeats) of each pupil's six upper anterior teeth, for tooth mottling. All clinical, radiographic and photographic data were then analysed. RESULTS: Mean DMFS scores were 9.18 (SD=10.72) for test users and 4.51 (SD=6.24) for control users (P<0.01) and, based on repeat observations, clinical reliability=0.99; X-ray reliability=0.95. Clinically, three test children had fluorosis of 10 teeth, with eight teeth in two controls. Photographic scoring by the clinical examiner gave a 97.2% clinical match, while photographic agreements for all four dentist pairs were 92.5%-97.2%, with lay observers' agreements at 89.8%. For both groups, 10% repeats produced 98.5% agreements. In a sole test case "fluorosis" photographic unanimity was obtained, and non-unanimous "possible fluorosis" was recorded by two to four panel members for only three other test and two control subjects. CONCLUSIONS: No evidence was found that significant anterior tooth fluorosis resulted in subjects exposed previously to 350 ppm F-/kg domestic salt from birth to 2.3-4.8 years of age. However, no caries benefit was demonstrated after the 11.5-year salt fluoridation gap. Caries differences seemed social class-related, city-based controls having less disease than rural test subjects, in spite of an identical F- tablet regimen in all schools from 1987, until subjects were 10 years old. These data emphasise (a) the superiority of sustained community-delivered fluoridation and (b) the need to maintain constant fluoride delivery to tooth surfaces, certainly well beyond 10 years of age.

Adolescent↗
PubMed1998

Integration of primary care dental and medical services: a three-year study.

OBJECTIVE: To develop and evaluate a model of integrated primary dental and medical care. DESIGN: 3-year prospective study. SETTING: A general dental practice and a general medical practice occupying the same building in Glasgow. INTERVENTION: Regular staff meetings, joint use of patient records systems and information derived from patient questionnaires. Dentistry was included in established screening programmes such as child health surveillance and care of elderly. Staff were encouraged to participate in joint work practices and joint consultations were carried out. MAIN OUTCOME MEASURES: Patient registration, avoidance of discrepancies in information, reduction of secondary referrals, joint work practices. RESULTS: The number of registered joint patients attending both medical and dental practices increased by 90%. The joint use of patient record systems avoided discrepancies in patient information which would have affected the quality of patient care. Including dentistry in child health surveillance and care of elderly screening programmes resulted in an increase in 0-5 year olds registering with dentists from 36% to 68% (P < 0.001) and with > 75 year olds from 47% to 71% (P < 0.001). Joint consultations reduced the need for secondary referrals. CONCLUSIONS: This model of health care demonstrated the potential for coordination and integration of functions between the dental team and the primary care team. Integrated primary dental and medical care requires attitudinal change in health care professionals and requires greater emphasis in education and training of health care professionals in the future.

Adolescent↗
PubMed1996

A survey of general anaesthesia, sedation and resuscitation in general dental practice.

The Poswillo Report, published in 1990, made recommendations regarding general anaesthesia (GA), sedation and resuscitation in dentistry. The aims of the present study were to examine the level of provision of GA and sedation by general dental practitioners (GDPs) a few years after the publication of the report, and to estimate the degree of compliance of GDPs with a number of its principal recommendations. In May 1994, a questionnaire was sent to 268 GDPs in two Scottish Health Boards, and a response rate of 80% was achieved. Thirteen per cent of respondents had treated GA cases during 1993-94 while 18% indicated that they had stopped providing a GA service since the immediate pre-Poswillo years. However, 91% had referred some patients elsewhere for treatment under GA. There was very little evidence of a replacement of GA by sedative techniques. The percentages of respondents using inhalation or intravenous sedation during the previous year were 9% and 27%, respectively. Almost all of the respondents reported that they had been trained in cardiopulmonary resuscitation and 60% stated that resuscitation exercises were practised at least once a year. While over 80% of the practitioners indicated that their dental surgeries stocked the emergency drugs recommended in the Poswillo Report, 12% expressed concern regarding the length and content of the drug list.

Anesthesia, Dental↗
PubMed1995

Computer modeling of the effects of chewing sugar-free and sucrose-containing gums on the pH changes in dental plaque associated with a cariogenic challenge at different intra-oral sites.

Variation in salivary access to different intra-oral sites is an important factor in the site-dependence of dental caries. This study explored, theoretically, how access is modified by chewing sugar-free and sugar-containing gums. A finite difference computer model, described elsewhere, was used. This allowed for diffusion and/or reaction of substrate, acid product, salivary buffers, and fixed-acid groups. Site-dependent saliva/plaque exchange was modeled in terms of a 100-microns-thick salivary film covering the plaque (a) flowing directly from the salivary ducts, (b) flowing from the intra-oral salivary pool, or (c) exchanging with the pool. Computed flow-velocities or rates of exchange were based on previous intra-oral measurements. The model was also tested against an in vitro study conducted by two of the authors. In addition, the three proposed models of saliva/plaque interaction were compared, and the effect of salivary film thickness investigate. Results suggested that: (1) although sugar-free gum chewed during a cariogenic challenge causes a rapid rise in plaque pH, sucrose-containing gums cause the pH, after a temporary rise resulting from increased salivary flow, to stay low for an extended period; (2) the computer model reproduced in vitro tests reasonably well; (3) although the three models of the plaque/saliva interaction start from different assumptions, two lead to closely related predictions; and (4) increasing the assumed salivary film thickness by a large amount (e.g., from 50 to 200 microns) caused no change in modeled Stephan curves, as long as these changes were accompanied by appropriate reductions in film velocity, in accord, theoretically, with the practical clearance data.

Acids↗
PubMed1995

The site-specificity of supragingival calculus deposition on the lingual surfaces of the six permanent lower anterior teeth in humans and the effects of age, sex, gum-chewing habits, and the time since the last prophylaxis on calculus scores.

The hypotheses to be tested were: (i) that chewing sugar-free gum frequently and for long periods would be associated with higher amounts of supragingival calculus, and (ii) that there would be no site-specificity of calculus deposition on the lingual surfaces of the 6 lower anterior teeth. Subjects, 436 in Glasgow and 191 in Winnipeg, were scored for calculus at mesial, lingual, and distal sites on the lingual surface of each of the 6 lower anterior teeth, by the Volpe-Manhold method. They also answered questions on the time since the last prophylaxis, the frequency of gum chewing, the type of gum chewed, and the length of a typical gum-chewing episode. A subset (233) of the Glasgow subjects were scaled and re-scored for calculus 3 months later. When the data for the logarithmic transformations of the initial calculus scores were subjected to stepwise multiple-regression analysis, the only factor which correlated significantly with initial calculus scores in both cities was the time since the last prophylaxis. In the Glasgow subjects scored 3 months after a prophylaxis, there was a negative correlation between chewing sugar-free gum and calculus scores, whereas in the Winnipeg subjects, age and the chewing of sucrose-containing and sugar-free gum were positively correlated with calculus scores. Thus, the results were contradictory with respect to the first-tested hypothesis. The calculus distribution patterns were very similar in the subset of Glasgow subjects and the Winnipeg subjects, with the amounts on the lateral incisors and canines averaging 70.2% and 44.5%, respectively, of those on the central incisors. Thus, the second hypothesis was disproved.

Adolescent↗
PubMed1994

Integration of primary care dental and medical services: a pilot investigation.

During the past decade the development of primary care medical services has been based on the medico-social model of health care delivery and this has resulted in the creation of the primary care team. These changes have so far not involved the general dental services. It was therefore decided to test the potential for coordination and integration of general dental practice in the primary care services. This started by examining a general medical and a general dental practice, occupying the same site, but functioning separately. Around 24% of patients were common to both practices. The initial data collected from a pilot study have been analysed and assessed in relation to patient attendance, record systems, staff cooperation, screening programmes, health promotion, patient referrals and staff education. The potential of this model for improving patient care and targeting the pre-school, middle-aged and elderly is described. It is concluded that coordinated primary care dental and medical services is an important area for further health services and educational research.

Dental Care↗
PubMed1994

Distribution of sucrose around the mouth and its clearance after a sucrose mouthrinse or consumption of three different foods.

The distribution of sucrose in whole saliva and in saliva from seven different regions of the mouth was determined in 10 subjects over the 10-min period following the chewing of a doughnut, sucking on a mint candy, the drinking of orange juice, or use of a 10% sucrose mouthrinse. With all products, the sucrose was distributed non-uniformly, with particularly low concentrations on the lingual surfaces of the lower incisors and the facial surfaces of the upper molars. Clearance was also most rapid from these sites. Since the depth and duration of a Stephan curve in dental plaque is influenced by the sugar concentration to which the plaque is exposed, the results, together with previous results on salivary film velocity in different regions of the mouth, help to provide an explanation for the site-specificity of smooth-surface caries and of supragingival calculus deposition.

Adult↗
PubMed1993

The effects of chewing-gum stick size and duration of chewing on salivary flow rate and sucrose and bicarbonate concentrations.

The objectives were to determine (1) the relations between salivary flow rate and the sample weights of chewing-gum and gum base, (2) whether any reduction in salivary flow rate with duration of chewing is due to a reduction in hardness of gum base with chewing, and (3) the sucrose and bicarbonate concentrations in saliva elicited by different weights of chewing-gum containing sucrose. Ten subjects chewed, for 20 min, samples of 1, 2, 3, 6 and 9 g of gum base and of a sucrose-containing chewing-gum. With each sample, salivary flow rates peaked initially and then fell to a relatively constant value. Flow rates during the periods of 1-2 and 15-20 min were linearly related to the logarithm of sample weight. With the chewing-gum samples, virtually all the sucrose was released into the saliva during the 20 min of chewing, with peak concentrations (201-666 mM) at 1-2 min, and bicarbonate concentrations were higher with the 9-g than the 3-g samples. Six subjects chewed 3 g of gum base and within 45 min the weight of base had increased to 122% of the original, presumably due to the uptake of saliva. The hardness of gum base was determined at 21 and 36 degrees C, 21 and 36 degrees C after it had been chewed, and 21 degrees C after it had been chewed without exposure to saliva, and gave Brinell values of 0.277, 0.038, 0.022, 0.002 and 0.061, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

An in vitro stimulation of the effects of chewing sugar-free and sugar-containing chewing gums on pH changes in dental plaque.

The objective of these studies was to simulate the effect of chewing sugar-free and sucrose-containing chewing gums on the return of the pH to neutrality after exposure to sucrose of plaque located on the buccal (BLM) and lingual (LLM) surfaces of the lower molar teeth. In study 1, a 0.5-mm-deep artificial plaque containing Streptococcus oralis cells was exposed to 10% sucrose for one min, and a 0.1-mm-thick film of sucrose-free artificial saliva was then flowed over the plaque surface at the unstimulated salivary film velocities previously found at the BLM and LLM sites. At the time of the pH minimum (pH 4-5), one of three conditions was simulated: (a) a no-gum-chewing control, or chewing for 20 min on either (b) a sugar-free gum or (c) a sucrose-containing gum. The recovery of the plaque pH to resting values was rapid during simulation of chewing a sugar-free gum (SFG), much slower with the no-gum control, and even slower with simulation of chewing a sucrose-containing gum (SCG). The pH recovery was slower with the BLM than the LLM plaque. In study 2, the BLM plaque was exposed to a 2% sucrose solution for 20 min under stimulated salivary conditions, to simulate the consumption of a meal, followed by one of conditions (a), (b), or (c) described above. The pH recovery with simulation of chewing a SCG was faster than with the no-gum control, but much slower than with the SFG simulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Bicarbonates↗
PubMed1992

Assessment of the cariogenic potential of Streptococcus mutans strains and its relationship to in vivo caries experience.

Strains of Streptococcus mutans isolated from the plaque of 6 subjects were studied using an in vitro model to determine whether differences in their cariogenic potential could be detected, and if so, whether the results correlated with the caries experience of the individuals. Each strain was incubated with a bovine enamel slab and 5% (w/v) sucrose for 24-h periods. The acidogenic potential was assessed by pH measurement and analysis of acid anion production. Microradiographic and microdensitometric assessment of the enamel, together with measurement of the change in calcium concentration of the reaction mixture were used to determine the demineralizing potential of each strain. Significant differences in cariogenic potential were found between some of the strains tested, and correlations were found between 3 of the test parameters and the decayed-missing-filled-surface score of the individuals. The results suggest that the caries experience of individuals may be related, to some extent, to the cariogenic potential of their S. mutans strains.

Acetates↗
PubMed1992

Effects of nine different chewing-gums and lozenges on salivary flow rate and pH.

The objectives of this study were to determine how salivary flow rate and pH vary with time during use of chewing-gums and lozenges. Twenty-four young adults collected unstimulated saliva and then, on different occasions, chewed one of six flavoured gums, or gum base, or sucked on one of two lozenges, for 20 min, during which time eight separate saliva samples were collected. Flow rate peaked during the 1st minute of stimulation with all nine products. With the lozenges, flow rate fell towards the unstimulated rate when the lozenges had dissolved. There were no significant differences in the flow rates elicited by cinnamon- or peppermint-flavoured gums or between sugar-containing or sugar-free gums. With the flavoured gums, the mean flow rate followed a power curve (r = -0.992) with time and within about 10 min was not significantly different from that when gum base was the stimulus. The initial stimulated flow rate with flavoured gums was about 10-12 times greater than the unstimulated rate (0.47 ml/min). After 20 min of chewing, it was still about 2.7 times that rate and about the same as the flow rate elicited by chewing-gum base alone. The pH of unstimulated saliva was about 6.95. With one gum containing about 1.5% organic acids, the salivary pH fell to a minimum of 6.18 in the 1st minute of stimulation, but then rose rapidly to a level above that in unstimulated saliva. With a sucrose-containing and a sucrose-free gum, the pH rose immediately on stimulation and then fell slightly with time to levels which were significantly above the pH of unstimulated saliva.

Administration, Oral↗
PubMed1991

Urea concentration in minor mucous gland secretions and the effect of salivary film velocity on urea metabolism by Streptococcus vestibularis in an artificial plaque.

Our purpose was to determine the urea concentration in minor mucous gland (MMG) secretions and the pH at proximal and distal aspects of the lower surface of artificial plaque in vitro during infusion of urea solutions over the surface, at different film velocities. Saliva is present in the mouth as a slowly moving film (ca. 0.1 mm thick) with an estimated velocity in the range of 0.8-8.0 mm/min. At low velocities, due to the accumulation of bacterial products, a progressive increase in their concentration may occur in both the plaque and the overlying salivary film at the distal edge (where the film leaves the plaque). S. vestibularis, an oral micro-organism possessing ureolytic activity, was combined with 1% agarose, to give a urease Vmax similar to that of natural plaque. The artificial plaque was in the chamber (6.0 x 6.0 square and 0.5 or 1.5 mm deep) of a diffusion apparatus, and a urea-containing artificial saliva (3.3 or 13.2 mmol/l) was infused over the surface, as a film 0.1 mm deep, at velocities of 0.8, 8.2 and 86.2 mm/min. At the lower (physiologically normal) urea concentration and the two lower film velocities, most urea appeared to be metabolized at the proximal end of the plaque, which developed a higher pH. At the higher urea concentration, and a film velocity of 8 mm/min, a higher pH was found at the distal end. This was probably due to the combination of greater urea availability and a reduced rate of ammonia loss distally. At a film velocity of 86.2 mm/min, proximal/distal pH gradients did not develop.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Comparison of the plaque microflora from natural and appliance-borne enamel surfaces.

Human enamel sections and slabs, mounted on a mandibular removable appliance, were worn by 5 adult subjects for a 1-week period. Plaque was allowed to accumulate on the in situ test sites and on the adjacent natural dentition. At the end of the experimental period, the plaque microflora associated with (1) the enamel sections, (2) the enamel slabs, and (3) the acrylic base of the appliance test site was compared with that obtained from lingual and interproximal areas of the lower molar teeth. In addition, the acid anion and pH profiles of plaque obtained from both the exogenous and natural tooth surfaces were also determined. Although some quantitative differences were found between the proportions of isolates obtained from the different enamel surfaces, qualitatively the microflora was very similar, and no significant differences were found in the plaque lactate/acetate ratios or pH measurements following a sucrose mouthrinse. Thus, human tooth specimens mounted on the intra-oral device produced a plaque ecosystem similar to that present on the adjacent natural dentition, suggesting that the model is suitable for studies on early plaque development and the microbiology of enamel demineralization.

Acrylic Resins↗