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Biomedical subjects

A W G Walls

Publications and source records attributed to A W G Walls.

15 recordsLinked to original sources

Prevalence of root caries in a selected population of older adults in Japan.

In this study, the prevalence of root caries in a sample of Japanese elders was investigated along with various aetiological factors. Two hundred and eighty-seven independently living elderly people over the age of 60 years were examined for the prevalence of active, inactive, and filled root lesions as well as the number of teeth. General health, oral status and brushing habits were surveyed, and salivary flow was determined in terms of flow rate and subjective feeling of dry mouth during eating. About 39% of the subjects had one or more decayed roots and 53.3% had at least one decayed or filled lesion. Root caries was seen most frequently on canine teeth followed by the first premolar. The number of decayed or filled lesions increased with increasing number of residual teeth (Kruskal-Wallis test, P = 0.033), however, there was no association between the proportion of teeth with root decay and the number of teeth. For subjects with 20 or more teeth, the number of decayed roots is likely to be lower in subjects who reported brushing frequently (P = 0.058), and higher in subjects with low salivary flow (P = 0.059) or subjective feeling of dry mouth (P = 0.052) (Chi-squared). The presence of decayed lesions is likely to be related to dry mouth (P = 0.057, odds ratio 3.13) and brushing frequency (P = 0.088, odds ratio 1.76) (Multiple logistic regression analysis). The results indicate a high frequency of root surface caries in this Japanese community-dwelling older population. Oral hygiene status and low salivary flow or perceived dry mouth were potential risk factors for disease.

Age Distribution↗

How do factors at different stages of the lifecourse contribute to oral-health-related quality of life in middle age for men and women?

The relative contributions of factors operating in fetal life, childhood, and adulthood to the risk of disease in middle age have become important research issues, but self-perceived oral health has rarely been considered in this context. This study investigated the impact of risk factors operating throughout life on self-perceived oral health, according to the Oral Health Impact Profile (OHIP), at age 50 yrs in 305 individuals from the Newcastle Thousand Families cohort. Factors from early and adult life contributed to the OHIP scores, but in men, self-perceived oral health was mostly explained by factors operating early in life. In women, the number of teeth retained in adulthood had a more prominent impact. Lifecourse influences on oral-health-related quality of life appear different for men and women, which may have implications for the effectiveness of public health interventions and health promotion.

England↗

Nutrition counseling increases fruit and vegetable intake in the edentulous.

Edentulous denture-wearers eat fewer fruits and vegetables than do comparable dentate individuals. Improved chewing ability with new dentures has resulted in little dietary improvement, suggesting that dietary intervention is necessary. The objective of this randomized controlled trial was to have a positive impact upon dietary behavior of patients receiving replacement complete dentures through a tailored dietary intervention. Readiness to change diet (Stage of Change), intake of fruits, vegetables, and nutrients, and chewing ability were assessed pre-and 6 weeks post-intervention. The intervention group (n = 30) received two dietary counseling sessions; the control group (n = 28) received current standard care. Perceived chewing ability significantly increased in both groups. There was significantly more movement from pre-action into action Stages of Change in the intervention group, who had a greater increase in fruit/vegetable consumption (+209 g/d) than did the control group (+26 g/d) (P = 0.001). Tailored dietary intervention contemporaneous with replacement dentures can positively change dietary behavior.

Aged↗

Film thickness and rheological properties of luting agents for crown cementation.

The film thickness and rheological properties [viscosity and tan sigma], of different resin based crown and bridge luting agents, including Panavia 21, Superbond, All Bond C&B Cement, Variolink were compared with zinc phosphate cement. A modification of the method in ISO 9917 (1991) and a controlled stress rheometer were used to monitor the changes in the film thickness and rheological properties respectively. For each material, the film thickness and rheological characteristics were determined at 60s after start of mixing and then made at regular intervals until immediately before the material was set. For the initial film thickness, the difference among the values for Varionk, Superbond and zinc phosphate cement was not significant (P>0.05), and less than 25microm. The values for All Bond C&B Cement and Panavia 21 were at least twice that of the other materials tested. All Bond C&B Cement produced the highest film thickness value at both the initial period and at 240s. Regarding viscosity, Superbond had the lowest initial value but the highest value at 240s. Variolink gave the highest initial value of viscosity, but the differences in the initial values among the other materials were small. During the whole period of testing, zinc phosphate cement gave the highest values of tan sigma, and Panavia 21 showed no significant change in any of the measured properties. The methods were able to distinguish the behaviour of different cement materials. Some resin cements produce larger than optimal values of film thickness and in some cases this is related to a rapid increase in viscosity after mixing. It is expected that differences in the ability of cements to form thin films will affect the seating of cemented restorations.

Analysis of Variance↗

Endodontic complications after plastic restorations in general practice.

AIM: To test the hypothesis that dentine and pulp protection by conditioning-and-sealing is no less effective than using a conventional calcium hydroxide lining. METHODOLOGY: A cohort of healthy adults requiring a new or replacement restoration in a posterior tooth was recruited in six general practices. All procedures received local Ethics Committee approval. Exclusion criteria included signs and symptoms of pulp necrosis or inflammation, and patients unable to commit to a long-term trial. Cavity preparations were randomized to receive a calcium hydroxide lining or conditioning-and-sealing with a smear-removing bonding system. Choice of bulk restorative material (composite resin or amalgam) was at the discretion of the dentist. The key outcome measure was evidence of pulpal breakdown identified at unscheduled (emergency) or scheduled recall examinations. Postoperative sensitivity was recorded on 100 mm VAS at 24 h, 4 days and 7 days. Pulp status was assessed at 6, 12, 24 and 36 month recall, and at any emergency recall appointment. The relationship between pre-treatment and treatment variables and pulp breakdown was assessed by logistic regression (P = 0.05). RESULTS: A total of 602 teeth were recruited, with comparable numbers of cavities lined (288, 47.8%) or conditioned and sealed (314, 52.2%). The majority (492, 81.7%) were replacement restorations, and amalgam was the most common bulk restorative material (377, 62.6%). A total of 390 (64.8%) restored teeth were reviewed at 6 months, 307 (51%) at 12 months, 363 (60.3%) at 24 months, and 279 (46.3%) at 36 months post-restoration. Sixteen cases of pulp breakdown were identified within 36 months of restoration placement, 11 presenting as emergencies and five detected at routine recall examination. Logistic regression showed that preoperative pain, cavity treatment by lining or conditioning-and-sealing and the use of rubber dam isolation had no association with pulp breakdown. Pulp breakdown was associated with deep or pulpally exposed cavities (P < 0.001, odds ratio 7.8) and with composite rather than amalgam restorations (P = 0.001, odds ratio 2.13). Re-coding to identify teeth with pulp exposures revealed that pulpal exposure was the key determinant of adverse pulp outcomes (P < 0.0001, odds ratio 28.4) and that composite resin restorations were again more likely to be associated with pulp breakdown than amalgam (P = 0.017, odds ratio 3.92). CONCLUSIONS: Considered within the context of routine primary dental care: Dentists can be confident that pulps will be equally well protected from post-restorative breakdown up to 36 months by calcium hydroxide lining and conditioning-and-sealing with adhesive resins. Residual dentine thickness appears to be a key determinant of pulp responses after restorative dental treatment. In deep and pulpally exposed cavities in posterior teeth, composites were associated with more pulpal breakdown than amalgams.

Acid Etching, Dental↗

Inhibition of root caries progression by an antibacterial adhesive.

A dentin primer containing the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) has been shown to penetrate and kill the bacteria in artificially demineralized dentin. We hypothesized that an experimental adhesive system, which incorporates the MDPB-containing primer, would be effective in inhibiting the progression of root caries in vitro. Artificial caries lesions were prepared by either an acid-gel or a Streptococcus mutans culture technique on the roots of extracted human teeth. The progression of these lesions after the application of the experimental or proprietary adhesive system was examined. Further demineralization was completely prevented by the experimental adhesive system, while lesions managed with the proprietary materials showed limited ability to inhibit further demineralization. We conclude that the experimental adhesive system can inhibit the progression of root-surface caries in vitro, through a combination of its antimicrobial activity and sealing of the demineralized dentin.

Acetone↗

The relationship between oral health and nutrition in older people.

The oral health of older people is changing with reducing numbers of people relying on complete dentures for function, and retaining some natural teeth. Despite this there are substantial numbers of older people whose ability to chew foods is compromised by their oral health status, either because they have few or no natural teeth. This alteration results in individuals selecting a diet that they can chew in comfort. Such diets are low in fruits and vegetables intake with associated reduction in both non-starch polysaccharide and micronutrient intakes. There is also a trend for reduced dietary intake overall. Salivary flow and function may have an impact in relation to the ability to chew and swallow. Whilst there are few differences in salivary function in fit healthy unmedicated subjects, disease resulting in reduced salivary flow and particularly polypharmacy, with xerostomia as a side effect, are likely to have a role in older people. This paper explores the relationships between oral health status and food's choice and discusses the potential consequences for the individual of such dietary change.

Aged↗

Do circumstances in early life contribute to tooth retention in middle age?

The relative contributions of factors operating in fetal life, childhood, and adulthood to risk of disease in middle age have become an important research issue, though oral health has rarely been considered. This study investigated the relative impacts of risk factors operating at different stages throughout life on the number of teeth retained at ages 49-51 yrs based on data from the Newcastle Thousand Families cohort. Very little variation in tooth retention in middle age was explained by factors operating at earlier stages in life. The previously noted relationship between childhood socio-economic status and oral health in adulthood appears, with respect to tooth retention, to diminish with increasing age as adult socio-economic position and lifestyle factors have an increasing effect. Promotion of a healthier adult lifestyle and continued improvements in oral hygiene would appear to be the public health interventions most likely to increase tooth retention in middle age.

Adolescent↗

Crowns and other extra-coronal restorations: resin-bonded metal restorations.

Resin-bonded metal restorations is the final part of the series. Cast metal restorations which rely on adhesion for attachment to teeth are attractive because of their potential to be much more conservative of tooth structure than conventional crowns which rely on preparation features providing macromechanical resistance and retention.

Cementation↗

Crowns and other extra-coronal restorations: porcelain laminate veneers.

Porcelain veneers are resin-bonded to the underlying tooth and provide a conservative method of improving appearance or modifying contour, without resorting to a full coverage crown. The porcelain laminate veneer is now a frequently prescribed restoration for anterior teeth. The sums spent by the Dental Practice Board on this type of treatment increased from quarter of a million pounds in 1988/89 to over seven million in 1994/95, representing some 113,582 treatments. Since that time the number has stabilised at over 100,000 veneers prescribed each year. The objective of this paper is to give a practical guide on providing these restorations.

Communication↗

Crowns and other extra-coronal restorations: impression materials and technique.

Well-fitting indirect restorations can only be made if there are accurate models of the oral tissues available, made from high quality impressions. Waiting for an impression to set may be more stressful for the dentist than the patient. Should the impression need to be repeated there is the embarrassment of having to explain this to the patient, the cost implications of material and time wasted and the aggravation of running late for the next appointment. Yet, if a 'Nelsonian' eye is turned to a defective impression we can only expect a substandard restoration in return.

Crowns↗

The relationship between oral health status and Body Mass Index among older people: a national survey of older people in Great Britain.

AIMS: To assess the relationship between oral health status and Body Mass Index. MATERIAL AND METHODS: This paper relates to the free-living sample (participants who lived in their own home, rather than an institution) of the National Diet and Nutrition Survey: people aged 65 years and older. SUBJECTS: 629 adults. DATA COLLECTION: A probability random national sample of adults who had a dental examination, an interview and an anthropometric examination. DATA ANALYSIS: Fisher's exact test and multivariate logistic modeling. FINDINGS: Being underweight was relatively uncommon in this population. People without teeth were significantly (P=0.05) more likely to be underweight than those with 11 or more teeth; 12.3% and 2.9%. A highly statistically significant (P=0.001) difference was observed in BMI between dentate people with 1-10 teeth and with more than 10 teeth; 24% and 2.9% were underweight. Dentate people with less than 21 natural teeth were on average more than 3 times more likely to be obese than those with 21-32 teeth (P=0.036). There was no significant difference in both the proportion of overweight and obese adults between those who were edentulous and dentate with 21 or more teeth. A similar pattern was observed when the number of posterior occluding pairs was compared with BMI categories. Results of multiple logistic regression were adjusted for the confounding effects of age, social class, region of origin and partial denture wearing. CONCLUSIONS: Older people in Britain with more than 20 teeth are more likely to have a normal Body Mass Index.

Aged↗

Crowns and extra-coronal restorations: materials selection.

Materials selection is the second in the series on crowns and other extra-coronal restorations. Some of us are less than inspired by dental materials science. Nevertheless, many of the things that concern us clinically with crowns and their alternatives are based on material properties. We worry about the strength of the restoration, how well it fits and its aesthetics. We also worry about wear, occlusal control and biocompatibility. Not least of our concerns are dental laboratory charges, which inevitably have to be passed on to the patient.

Biocompatible Materials↗

Changing patterns and the need for quality.

This series of articles is aimed at anybody who places crowns and other extra-coronal restorations (ie veneers and shims) on individual teeth. We hope that everyone from experienced practitioners to undergraduate students may find something of value. Whoever reads them, we would ask to do so with an open mind. We have tried not to be dogmatic, and the techniques and materials described are not the only ones available, but are the ones which accord with the principles we describe.

Crowns↗