A.J. Preston

Risk Groups: Nursing Bottle Caries/Caries in the Elderly

Despite the well-known decline in the overall prevalence and incidence of dental caries in the Western societies, there remain persistent pockets of high caries. These are located generally within inner-city, low-socio-economic and immigrant populations throughout Europe and elsewhere. However, two other groups continue to record high caries: the very young and the elderly. Both show remarkable similarities in their characteristics and in many ways caries has the same aetiology, prevalence, treatment and preventive strategies. Both groups of people are mainly dependent on others for their care. Pre-school children are looked after by their parents who dictate their lives including choice of food, diet and oral care. The elderly are a mixed group. Firstly, there are the young elderly who are free living and totally look after themselves. Secondly, there are the elderly who are partially dependent and require support but mainly choose their own life-styles, including diet, and are responsible for their own oral care. Finally, there are the sick elderly who are dependent on carers who, just like the parents of the very young, dictate diet, food choice and provide oral care. It is mainly the third group of elderly, and to a lesser extent the second group, that present a problem of dental caries. These two groups of people pose a serious and difficult problem for dentistry in that they may present with high levels of dental caries and a significant percentage of the population are affected. In both instances the aetiology is multi-factorial and diet plays a major role. But the choice of diet may not be their own and they may often be victims of ignorance and poor practice by others. In addition, the prevention of dental caries is also dependent on the actions of their carers. Both the elderly and very young can be difficult to treat because of poor co-operation or behavioural problems. Thus, the dental profession is challenged by children and the elderly to devise not only workable prevention strategies but also methods of treatment and oral care.

Oral Flora of Elderly Patients following Acute Medical Admission

The human oral microflora is diverse and is usually predominately composed of Gram-positive bacteria. It is uncommon to find Gram-negative bacilli (GNB) in healthy mouths. The incidence of infection with GNB rises in institutionalised, frail elderly subjects. There is also evidence of an association between intra-oral GNB presence and denture wearing. There have been few studies which have investigated intra-oral GNB carriage in acutely ill elderly patients. The aim of this study was to evaluate the oral flora of a group of elderly patients during an acute medical admission and to investigate any associations between the oral microflora and existing medical or oral factors. A total of 28 patients (17 females and 11 males; age: 74–93 years) on a care for the elderly ward were studied. Epidemiological data, detailed medical histories and oral examinations were undertaken. In addition, oral swabs of the palate area were taken to determine their oral flora. Twelve (43%) of the patients had GNB in their oral cavities. These patients were suffering from a variety of medical conditions and were on various drug regimes. There was a correlation between oral GNB presence and denture use. There was no association between GNB presence and denture hygiene. As oropharyngeal GNB colonisation can be associated with infections such as aspiration pneumonia, it is important in patients at risk that intra-oral organisms are identified and managed.

The recharge of esthetic dental restorative materials with fluoride in vitro—two years' results

OBJECTIVES A range of esthetic restorative dental materials are now available to dental clinicians. The aim of this study was to evaluate the relative fluoride recharge potential of a number of these materials in vitro over two years. METHODS Disc samples (12 mm x 2 mm) of each of the materials were placed into artificial saliva at neutral pH. The materials tested were: two glass ionomers (Chemfil; Ketac-Fil), two resin-modified glass ionomers (Photac-Fil Aplicap; Vitremer), two compomers (Dyract; Compoglass) and two composites (Heliomolar; Concise). At 13 intervals over a two years period the discs were subjected to a 2 min fluoride recharge by exposure to sodium fluoride (500 ppm F). The pre- and post-recharge fluoride release values were determined using an ion sensitive electrode. RESULTS At all time intervals the post-recharge fluoride release of the materials was significantly different (MANOVA p<0.0001). The mean values for post-recharge fluoride release after two years were: Chemfil 10.3, Ketac 3.0, Vitremer 9.0, Photac-Fil Aplicap 12.1, Compoglass 5.0, Dyract 3.6, Concise 0.3, Heliomolar 0.2 (units = microgF/cm(2)/h). SIGNIFICANCE Esthetic fillings vary significantly in their capacity to absorb and re-release fluoride. The glass ionomer-based materials displayed a far greater potential for fluoride recharge than the composites, in which the recharge was virtually negligible. Whilst it cannot be assumed that fluoride release is directly proportional to cariostatic potential, these results suggest that, where possible, glass ionomer-based materials should be used in patients who have a high caries rate.

Endodontics in the adult patient: the role of antibiotics.

OBJECTIVES The aim of this study was to review the published work on the indications and efficacy for antibiotics in endodontic therapy. DATA SOURCES Published works in the medical and dental literature. STUDY SELECTION Evaluation of published clinical trials in endodontic and other pertinent literature. CONCLUSIONS Antibiotics are not routinely indicated in the practice of endodontics. Therapeutic antibiotics may be required as an adjunct to operative treatment when there is pyrexia and/or gross local swelling; they are only rarely indicated in the absence of operative intervention. Prophylactic antibiotics may be required for certain patients who are susceptible to serious infective sequaelae.

Assessment of perceptibility and acceptability of color difference of denture teeth.

OBJECTIVES To assess the color difference values that represent the perceptibility and acceptability thresholds of denture teeth. METHODS Eighteen interchangeable right upper central incisors denture teeth were selected to have color difference values from representative left upper central incisor denture tooth in a range of 0.4-11.4 ΔE* units measured with a spectrophotometer (CM 2600d, Minolta Konica, Japan). These teeth were placed in an artificial dental arch in a phantom head. Under controlled conditions, a total of 80 observers divided into 4 groups (technicians, nurses, dentists and researchers) were asked to report the perceptibility and acceptability of each of the color difference values. The findings was then analysed using logistic regression for determining the perceptible and acceptable thresholds of dental color differences. RESULTS The determined color difference values at which 50% of all observers could detect a color difference (50:50 probability) was 1.9 ΔE* units with a 95% confidence interval and ranged from 1.7 ΔE* units to 2.1 ΔE* units. The determined color difference value at which 50% of all observes preferred to replace the tooth because of unacceptable color difference (50:50 probability) was 4.2 with a 95% confidence interval that ranged from 3.9 ΔE* units to 4.7 ΔE* units. CONCLUSIONS Within the limitation of this study, the following conclusions were made: 1. The mean color perceptibility threshold was significantly lower than the mean color acceptability threshold. 2. Significant differences between different observers groups were noticed in determination of perceptibility and acceptability of color differences. The technicians groups displayed lower perceptibility and acceptability limits than the dental nurses and non-dental observers. CLINICAL SIGNIFICANCE When shade matching artificial denture teeth to natural teeth, 50:50 perceptibility (1.9 ΔE* units) and acceptability (4.2 ΔE* units) thresholds are used to compare color difference values. The technicians group displayed lower perceptibility and acceptability limits than other observers.

The erosive potential of some alcopops using bovine enamel: an in vitro study.

OBJECTIVES Alcoholic soft drinks have become increasingly popular and have high concentrations of citric acid and alcohol so might have the potential to cause dental erosion. This study aimed to investigate the erosive potential of alcopops on bovine enamel in vitro. METHODS Six bovine upper incisors were prepared and sectioned to give six slabs per tooth, 4mm x 4mm each. Each slab was covered with nail varnish, leaving an exposed window (2mm x 2mm). Samples were immersed in 20ml of each of the test solutions for 20min, 1h, and 24h under gentle agitation (100rpm). Enamel surface loss was determined using Quantitative Laser Fluorescence (QLF), Non-contact Profilometry (NCP) and Transverse Microradiography (TMR). RESULTS Enamel loss occurred with all test drinks and the positive control (p<0.05), and the depth of lesion correlated with pH and time. No significant difference was observed between 20min and 1h exposure, although both times had significantly (p<0.05) greater erosion when compared with baseline. Within each alcopops group significant erosion had occurred at 24h exposure compared with the baseline and previous times. CONCLUSION All the tested alcopops resulted in significant enamel loss at 24h (p<0.001) with direct correlation between degree of enamel loss and both pH and increasing exposure time.

A study investigating the formation of artificial sub-surface enamel caries-like lesions in deciduous and permanent teeth in the presence and absence of fluoride

OBJECTIVES Clinical and in situ studies have shown that caries formation and progression is faster in primary than in permanent teeth. Ambient levels of fluoride are also known to influence the processes of carious lesion formation. The aims were, firstly to investigate the incidence of artificial sub-surface caries lesion formation in the enamel of deciduous and permanent teeth in vitro. Secondly, to compare quantitatively the mineral content and distribution of these lesions and assess the possible influence of fluoride upon the lesion parameters. METHODS Twenty primary molars and 20 permanent premolars were randomly assigned to one of four experimental groups. Samples in each experimental group were immersed in a 0.05M lactic acid gel (6% w/v hydroxyethyl cellulose, pH 4.5) either in the absence or presence of fluoride for 7 days. Subsequently, lesion parameters of mineral loss (vol x % microm) and lesion depth (microm) were assessed by transverse microradiography and image analysis. RESULTS No significant differences existed between the lesion parameters of permanent and primary teeth (P=0.20). Irrespective of tooth type, lesion parameters were significantly reduced in samples demineralised in the presence of fluoride (P< or =0.002). CONCLUSIONS Fluoride significantly reduces the severity of sub-surface caries lesions formed in vitro and in contrary to previous studies, there were no significant differences in lesions parameters between permanent and primary teeth.

Pseudomonas aeruginosa septicaemia from an oral source.

Oral colonisation with aerobic Gram-negative bacilli (AGNB) is abnormal and usually indicates a medically compromised state in the host. It has been postulated that oral colonisation with AGNB may predispose a patient to serious systemic infection, but proof of this assertion is lacking. This report describes an elderly patient who had oral colonisation of Pseudomonas aeruginosa and developed septicaemia from an identical strain of this bacterium.

Comparison of the Effects of Whole and Juiced Fruits and Vegetables on Enamel Demineralisation in situ

We compared the effect on enamel demineralisation in situ of both whole and juiced fruits and vegetables. Volunteers wore removable mandibular appliances carrying pre-demineralised human enamel slabs and consumed one of the test foods 7 times a day for 10 days. The test foods were apples, oranges, grapes, carrots, and tomatoes, consumed either whole (sugars located intrinsically) or as a juice (extrinsic or free sugars). Raisins containing 64% sugars, but intrinsic by definition, were also studied. The mineral profile of the enamel slabs was studied before and after the test period using transverse microradiography and showed further demineralisation for all test foods, irrespective of the form of consumption. Significant demineralisation was also observed with raisins. No significant differences were found between the solid and juiced foods. In conclusion, sugars present intrinsically on consumption had a similar demineralising potential as free sugars and could not be considered less cariogenic.

A COMPARISON OF THREE ELECTRODES FOR THE MEASUREMENT OF PH IN SMALL VOLUMES

An ion-sensitive field effect transistor (ISFET, Sentron, Sentron, Inc.) electrode was compared with a glass combination micro-electrode (MI-410, Micro-electrodes, Inc.) and a solid-state metal wire oxide pH sensor (Beetrode, World Precision Instruments, Inc.) with a liquid junction reference electrode (MERE1, World Precision Instruments, Inc.). The electrodes were assessed for linearity, reproducibility, accuracy, drift from the initial calibration between pH 4 and pH 7 and the time taken to record a stable reading. The ISFET was used to determine the pH in dental plaque samples (1 mg suspended in 20 microliters). The pH values correlated with the hydrogen ion concentration for all the electrodes (r = 0.98). The MI-410 fractured before this evaluation was completed. Coefficients of variation were 0.65% (pH 4) and 0.08% (pH 7) for the ISFET and 4.69% (pH 4) and 3.46% (pH 7) for the Beetrode. Both electrodes gave readings that differed significantly from the initial calibration, but the drift was greater for the Beetrode (F = 7.93; p = 0.0005) than the ISFET (F = 1.89; p = 0.1519). However, this drift was smaller than the change in pH as measured in dental plaque samples. The Beetrode gave a stable reading after 3.39 +/- 0.83 s and the ISFET after 2.2 +/- 0.76 s, while the MI-410 required at least 20 s. The ISFET type electrode is suitable for use in small volumes such as plaque suspensions, is easier to operate and yields results closer to the initial calibration than the Beetrode and is more robust than the MI-410 and the Beetrode.