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PubMed1996

A 6-month home-usage trial of 0.1% and 0.2% delmopinol mouthwashes (I). Effects on plaque, gingivitis, supragingival calculus and tooth staining.

Delmopinol is a morpholinoethanol derivative which, in mouthrinses used in the absence of normal oral hygiene, has been shown effective in the inhibition of plaque and gingivitis. The aim of this study was to determine the adjunctive oral hygiene benefits and safety of delmopinol rinses when used alongside normal toothcleaning. This 6-month home use study was a placebo-controlled, double-blind, randomised parallel design evaluating 0.1% and 0.2% delmopinol rinses and structured to conform with the ADA Council of Dental Therapeutics guidelines. A total of 450 dentate male and female subjects were recruited who had no relevant medical or pharmacotherapy histories determined from a full medical examination, including haematological and biochemical tests. Subjects had moderate levels of plaque and gingivitis. At baseline, 3 and 6 months subjects were scored for plaque, gingivitis, tooth stain and supragingival calculus, with plaque sampled for microbiological analysis. Additionally, oral mucosal examinations were performed and subjects questioned for adverse symptoms. Baseline special tests were repeated at the end of the study. After baseline examinations, the subjects received a professional prophylaxis, provided with the allocated mouthwash and instructed to use 10-ml volumes for 60 s 2 x daily and where appropriate after toothbrushing and meals. Demographic features of the 3 groups were similar and losses to trial were small. Adverse signs and symptoms included transitory numbness of the tongue, tooth and tongue staining, taste disturbance and rarely mucosal soreness and erosion. All local side-effects were less commonly reported at 6 compared to 3 months and only 6 subjects were withdrawn because of adverse event. No systemic effects attributable to the agent were observed and no significant shifts in haematological or biochemical parameters occurred. All groups showed considerable improvements in oral hygiene and gingival health with some significant differences in favour of 0.2% delmopinol compared to placebo for gingivitis and more particularly plaque. Staining was also significantly increased in the delmopinol groups but not calculus. In the present study, a considerable Hawthorne effect occurred, which must in part explain why only a modestly significant effect was achieved.

Adult↗
PubMed1997

A short-term clinical study design to investigate the chemical plaque inhibitory properties of mouthrinses when used as adjuncts to toothpastes: applied to chlorhexidine.

The removal of plaque by toothbrushing with toothpaste is the most common form of plaque control in the developed world. However, the use of chemical adjuncts such as mouthrinses is increasing. In practice mouthrinses and toothpaste are used together, however, in many clinical trials, employed to assess mouthrinse activity, toothpaste use is suspended. This fails to measure the effect of chemical interactions which are known to occur between toothpaste ingredients and mouthrinses. The objective of this trial was to develop a methodology which would assess the adjunctive chemical plaque inhibitory action of mouthrinses, when used with toothpaste but without the indeterminate variable of toothbrushing. The study was a single blind, randomised, 7-way crossover design, based on a variation of a 4 day plaque regrowth model. The 2 x daily rinsing regimens produced increasing plaque scores in the following order: (1) water/chlorhexidine, (2) chlorhexidine/water, (3) chlorhexidine/toothpaste slurry, (4) toothpaste slurry/chlorhexidine, (5) water/toothpaste slurry, (6) toothpaste slurry/water, (7) water/water. Chlorhexidine and water or chlorhexidine and toothpaste slurry combinations produced significantly lower plaque scores than water alone. Slurry and water combinations resulted in less plaque than water alone, but differences were not significant. Toothpaste slurry and chlorhexidine produced significantly increased plaque scores compared to chlorhexidine and water. The study suggests that, outside the Hawthorne effect, chlorhexidine rinses would be less effective in reducing plaque when used with toothpaste than when used alone. The methodology could be employed as a screening tool for the evaluation of mouthrinses expected to be used as adjuncts to normal oral hygiene methods. The same could be used to optimise oral hygiene regimens which include the use of mouthrinses.

Adult↗
PubMed1997

An 18-week home-use study comparing the oral hygiene and gingival health benefits of triclosan and fluoride toothpastes.

Several triclosan and stannous fluoride toothpastes have been shown to have plaque inhibitory and more particularly gingival health benefits when compared to minus active controls. There have been relatively few studies to compare such products with conventional fluoride toothpastes in home use. The aim of this study was to compare the relative gingival health benefits of a triclosan/zinc citrate, triclosan/copolymer, stannous fluoride and conventional fluoride toothpastes in a home use study. The study was a double blind, parallel design with a total 143 healthy dentate volunteers (41 male, 102 female) who toothbrushed 2x daily with 1 of 4 toothpastes over an 18 week period. At the beginning of the trial, each volunteer was scored for plaque and gingivitis and then received a thorough prophylaxis. Each volunteer was allocated a toothpaste according to a predetermined randomisation scheme. The volunteers were then re-examined after 6, 12 and 18 weeks. No other oral hygiene products were used during this period. The results showed no statistically significant treatment differences between products for the gingival index throughout the 18 week-trial. No statistically significant treatment effects between products for plaque index were found at 6 or 18 weeks. However, a small but statistically significant treatment effect for plaque index was seen at 12 weeks in favour of the triclosan/copolymer toothpaste compared to the stannous fluoride and conventional fluoride toothpastes, this difference had disappeared by the 18 week examination. All volunteers oral hygiene and gingivitis scores improved after the baseline examination, and this improvement continued throughout the trial. This is a feature of nearly all toothbrushing studies and can be attributed to the initial prophylaxis and the Hawthorne phenomenon. Such phenomena, noted in home use clinical trials, may mask the efficacy of proven antiplaque formulations.

Adolescent↗
PubMed1996

Structural comparison of a translated dental attitude questionnaire: a factor analytic study.

In 1984 the Dental Attitude Questionnaire (DAQ), an instrument for assessing various aspects of a person's attitude toward oral health care, was presented by STOCKWELL & BANTING. The DAQ consists of six content scales, Cynicism, Health Concern, Motivation, Oral Function, Social Aesthetic and Susceptibility, and two validity scales, Halo and Infrequency. A Dutch translation was presented in 1986 by HOOGSTRATEN & BROERS. In order to replicate the factor analysis on the original DAQ as reported by STOCKWELL & BANTING, the present study was undertaken. The results show a change in factor structure from a three factor solution to a two factor solution. A confirmatory factor analysis shows that the original three factor structure of the DAQ is not present in the data collected with the translated version. To account for this change, some possible reasons are discussed.

Adult↗
PubMed1998

Evaluation for an observation effect in a prospective cohort study of oral health outcomes.

OBJECTIVES: Evaluation for changes in behavior due to research participants' knowledge that behavior is being observed (also referred to as a Hawthorne effect or reactivity) has received little attention in the dental literature. The Florida Dental Care Study, a prospective, non-randomized, longitudinal study of oral health outcomes, provides some inferential power to evaluate for an effect on dental care use due to participants' knowledge that this behavior was being observed. The purpose of this paper is to document that an observation effect can occur in dental studies, and to estimate its magnitude in four groups that were defined by their typical approach to dental care as stated at baseline: consistent regular attenders (CRAs); inconsistent regular attenders (IRAs); consistent problem-oriented attenders (CPOAs); and inconsistent problem-oriented attenders (IPOAs). METHODS: At baseline, 873 respondents with at least one natural tooth and who were 45 years of age or older participated for an interview and clinical dental examination. Respondents were asked about their dental care use in general and check-up use in particular at 6-month intervals over a period of 24 months. RESULTS: Dental care use in general and check-up use in particular varied across time points and across the four groups of the sample. There was some stimulation in dental care use for the sample overall, but by the 18-to-24-month period, use had returned to baseline levels. In a direction opposite from that hypothesized, results from the CRAs suggested decreased use of dental care over the course of the 24 months of observation. No consistent pattern was evident for the IRAs, CPOAs, or IPOAs. CONCLUSIONS: An observation effect was evident, but was modest in magnitude and differed within and between sub-groups of the sample. While self-selection into dental care user groups is an expected and desirable feature of this design, the size of the user/non-user groups was affected for some subgroups. We conclude that dental care studies with the potential for an observation effect should evaluate for this effect by distinguishing sub-groups of the sample based on their propensity (as stated at baseline) to use dental care. These differential effects across sub-groups should be taken into account as inferences are made.

Chi-Square Distribution↗
PubMed1994

Breast feeding and acute lower respiratory infection.

The association between breast feeding and acute lower respiratory infection (ALRI) was studied in a case-control study in southern Italy. Two groups of children were studied: the first group comprised 73 infants, aged 0-6 months, whose diagnosis was pneumonia or bronchiolitis; the second group included 88 infants less than 12 months of age with a diagnosis of pertussis-like illness. Control infants were two groups of infants admitted to the same ward. Compared with controls, infants in the first group were less likely to have been breast fed (odds ratio 0.42, 95% CI 0.19-0.90). The protection conferred by breast feeding was stronger among infants who were receiving human milk at the time of admission (odds ratio 0.22, 95% CI 0.09-0.55) and was absent among those infants who had stopped breast feeding for two or more weeks before admission. Among infants who were severely ill, breast feeding was less likely than among those with milder illnesses. There was evidence in the stratified analysis of effect modification by the presence of other children in the family. Among the infants with pertussis-like illness, the incidence and duration of breast feeding were not different compared with controls. The results suggest that breast feeding has a strong protective effect against ALRI in industrialized countries also. No protection seems to be conferred by human milk against pertussis-like illness.

Acute Disease↗
PubMed2000

A meta-analysis examining effects of school sexuality education programs on adolescents' sexual knowledge, 1960-1997.

This study analyzed and synthesized findings from selected studies conducted from 1960 through 1997 regarding effects of school sexuality education on adolescents' sexual knowledge. This purpose was achieved using meta-analysis. Sixty-seven studies that met the selection criteria were included in the meta-analysis. The 67 studies reported 72 outcomes regarding sexual knowledge, which were grouped into six independent variables related to knowledge about sexuality. A weighted effect size method developed by Hedges and Olkin was calculated using all studies. For all studies, 97% of weighted effect sizes were positive. The weighted average effect size on sexual knowledge across all studies of 0.41 was statistically significant, indicating a significant difference occurred between control and experimental groups' mastery of objectives related to sexual knowledge. It was concluded that sexuality education programs positively affect overall sexual knowledge.

Adolescent↗
PubMed1993

Can we learn anything from small trials?

In summary, then, we can learn three useful things from small clinical trials. First, we can learn when to challenge conventional but untested therapeutic wisdom. Second, because the patient number in any trial is the number of events, rather than the number of study patients, some small trials are so definitively positive that they are sufficient to identify the best therapy. And third, small trials, even when individually inconclusive, can serve as the basis for convincingly conclusive overviews and meta-analyses that carry, and deserve, greater credibility than a single large trial of similar size to their sum.

Bias↗
PubMed1993

Collaborative worldwide overviews of randomized trials.

Formal overviews (or meta-analyses) are now widely accepted as the most reliable way to evaluate the evidence from several randomized controlled trials that have all assessed a particular form of therapy. If a limited amount of trial data has accumulated, overviews can be undertaken at a relatively simple level, assembling just summary data extracted from published reports. Such overviews are likely to be incomplete and biased and may (because of the restricted number of analyses that are possible) not answer all the clinically important questions that might be addressed. Where a particularly large body of data from randomized trials has accumulated, more thorough and detailed overview analyses are needed. Such detailed reviews are greatly facilitated if a collaborative group of all the trialists is formed. Such groups have sought to collate individual patient data (a very few key items for every patient randomized). A central statistical secretariat then coordinates the process of data collection, checking, and analysis. Analyses are presented to the whole group for discussion and final reports are published in the name of the whole group. Experience from two very large groups that have followed this model, the Antiplatelet Trialists' Collaboration and the Early Breast Cancer Trialists' Collaborative Group, has shown that detailed collaborative overviews have many benefits: the results are particularly clear and therefore have substantial public health impact; the areas of statistical and medical agreement on the evidence can be defined; the areas of uncertainty (and hence future research priorities) are clarified; and the group can disseminate the results particularly widely and rapidly.

Bias↗
PubMed2000

Response and nonresponse bias in oral health surveys.

Oral health surveys are undertaken to provide estimates of the dental health and behaviors of populations or population subgroups. However, the integrity of the data from sample surveys may be compromised by one or more sources of sampling and nonsampling error. An important source of nonsampling error is the failure to collect data from some of the individuals comprising the sample. Consequently, the response to a sample survey, and the direction and magnitude of bias induced by nonresponse, need to be taken into account when using estimates derived from sample surveys. Although the response rate to a survey is usually used as an indicator of the quality of the data it provides, nonresponse error is a function of nonresponse and the extent of differences in the characteristics of responders and nonresponders. Nonresponse may be managed in two ways. The first is to reduce nonresponse to a minimum using response-enhancement strategies. The second is the post-survey adjustment of data using weighting or imputation techniques to produce estimates that correct for nonresponse. This paper discusses issues concerning response and nonresponse bias in oral health surveys and provides guidelines on the management and reporting of nonresponse. It describes response-enhancement strategies to reduce noncontacts and refusals, sources of data to facilitate the comparison of responders and nonresponders, methods of assessing the degree of bias induced by nonresponse, techniques for producing adjusted survey estimates, and the assumptions on which these procedures and processes are based.

Bias↗
PubMed1992

The effect of a five-month delay on children's and adults' eyewitness memory.

Child witnesses must endure a delay of around six months between observing or being the victim of an alleged offence and being required to give evidence in a criminal court. While the legal profession seem to believe that young children's memories are particularly sensitive to the passage of time, developmental psychology can offer little relevant data to support or refute this presumption. In the present study, children aged six and nine years and adults witnessed a staged event and were subsequently interviewed in the days following the event and/or five months later. Results indicate that while all witnesses forgot information over this period, the younger children (six years) recalled slightly less information than the older children and the adults. The total amount of incorrect information recalled did not increase over the same period. Two different interviewing techniques were used--cued recall vs. 'enhanced' recall--the latter incorporating some aspects of the cognitive interview procedure. No differences were found relating to the interview techniques employed. The results underline the importance of recording initial interviews with child witnesses wherever possible.

Adult↗
PubMed2004

Noise annoyance from stationary sources: relationships with exposure metric day-evening-night level (DENL) and their confidence intervals.

Relationships between exposure to noise [metric: day-evening-night levels (DENL)] from stationary sources (shunting yards, a seasonal industry, and other industries) and annoyance are presented. Curves are presented for expected annoyance score, the percentage "highly annoyed" (%HA, cutoff at 72 on a scale from 0 to 100), the percentage "annoyed" (%A, cutoff at 50 on a scale from 0 to 100), and the percentage "(at least) a little annoyed" (%LA, cutoff at 28 on a scale from 0 to 100). The estimates of the parameters of the relations are based on the data from a field study (N=1875) at 11 locations (2 shunting yards, 1 seasonal industry, 8 other industries) in the Netherlands. With the same (yearly) DENL, the seasonal industry causes less annoyance than the other industries, while the other industries cause less annoyance than the shunting yards. It appears that annoyance caused by vibrations from shunting yards and annoyance caused by noise from through trains are (partly) responsible for the relatively high annoyance from shunting yards. The relatively low annoyance from the seasonal industry presumably is related to the presence of a relatively quiet period. Results for the two shunting yards and the seasonal industry are based on fewer data than the other industrial sources, and are indicative. The same patterns of influence of age and noise sensitivity that are generally found are also found in this study. For comparison, results regarding transportation sources are also given, including previously unpublished results for expected annoyance.

Adult↗
PubMed2005

Understanding systematic reviews and meta-analysis.

This review covers the basic principles of systematic reviews and meta-analyses. The problems associated with traditional narrative reviews are discussed, as is the role of systematic reviews in limiting bias associated with the assembly, critical appraisal, and synthesis of studies addressing specific clinical questions. Important issues that need to be considered when appraising a systematic review or meta-analysis are outlined, and some of the terms used in the reporting of systematic reviews and meta-analyses--such as odds ratio, relative risk, confidence interval, and the forest plot--are introduced.

Child↗
PubMed1990

Postal survey on airborne occupational exposure and respiratory disorders in Norway: causes and consequences of non-response.

STUDY OBJECTIVE: The aim was to examine causes for non-response in a community survey, and how non-response influences prevalence estimates of some exposure and disease variables, and associations between the variables. DESIGN: This was a cross sectional questionnaire study with two reminder letters. The questionnaire asked for information on smoking habits, occupational airborne exposure and respiratory disorders. SETTING: A random sample of 4992 subjects from the general population aged 15-70 years of Hordaland County, Norway. MAIN RESULTS: The overall response rate was 90%, with a 63% response to the initial letter. The response rates to the first and second reminder letters were 56% and 36% respectively. In 20% of the non-respondents an uncompleted questionnaire was returned with cause for non-response; in two thirds of these the cause for non-response was that the subject was not resident at the mailing address. A home visit to a random sample of 50 urban non-respondents provided further information on 29 subjects. A wrong address at the Central Population Registry and the subject's feeling of lack of personal benefit from a postal survey were the major reasons for non-response. Smokers were late respondents and subjects with respiratory disorders tended to be early respondents. CONCLUSION: The main reasons for non-response were a wrong mailing address and a feeling of lack of personal benefit from responding. Using only the initial letter would have changed the estimated prevalence of smokers from 39% to 35%. Otherwise, the estimated prevalence of the exposure and disease variables as well as the associations between them were only slightly changed after including the respondents to the first and second reminder letters.

Adolescent↗
PubMed1991

Investigating the proxy effect and the saliency principle in household based postal questionnaires.

STUDY OBJECTIVE: The aim was to investigate two possible sources of bias inherent in using a household based postal questionnaire, the "proxy effect", inaccurate reporting about characteristics of others, and the "saliency principle", reporting of only the most salient features. This is of importance in surveys concerned with screening the population to identify individuals with certain characteristics, and so possibly relying on one member of the household to reply on behalf of all others. DESIGN AND SETTING: A two stage survey of disablement in the population was undertaken. A first phase postal questionnaire was sent to 25,168 households in Calderdale, West Yorkshire, England, to ascertain the prevalence of physical disability and of troubles with the joints. The second phase comprised in depth interviews with a sample of individuals identified in the first phase as being disabled. RESPONDENTS: A total of 21,889 postal questionnaires were returned (87%) representing households containing 42,826 people aged 16 years and over. A disproportionately stratified random sample of 950 respondents reporting disability was taken in the second phase. Of these 891 were still available, and 838 (94%) were interviewed. MEASUREMENTS AND MAIN RESULTS: The postal questionnaire found that almost 29% of those who lived "alone" (without another adult) reported some level of disability, compared to only 10% of those who lived with others. The difference remained significant after standardisation. This apparent underreporting or "proxy effect" was present for reporting about disability overall, but not for severe disability (dependence on help of others), which suggests the operation of the "saliency principle". Reporting on joint troubles appeared to be affected by the proxy effect both for any joint problems, and when more than five joints were affected. Analysis of a small set of postal questionnaires from respondents who reported joint problems only at interview and where we could identify who had completed the postal questionnaire supports the hypothesis of a proxy effect; two thirds of the original postal questionnaires had been completed by a proxy. The results were further complicated by an interaction between reporting of disability and joint troubles: the greater the level of disability, the less likely the reporting of joint troubles. CONCLUSIONS: The findings have general implications for studies involving postal household screening questionnaires, and raises additional concerns about those that are multitopic in content. In surveys of symptoms and minor disability, a proxy effect is likely to be operative. This effect is not apparent for obvious and long standing problems such as dependence on others for help. However the interaction between the reporting of disability and joint symptoms carries important implications for the development of multitopic postal screening questionnaires.

Adolescent↗
PubMed2000

Incidence of myocardial infarction in women. A cohort study of risk factors and modifiers of effect.

STUDY OBJECTIVE: To assess whether the increased incidence of myocardial infarction and death associated with smoking, hypertension, hyperlipidaemia and diabetes varies significantly between groups defined in terms of occupation, education and marital status. SETTING: Malmö, Sweden. PARTICIPANTS: 9351 women, aged 28-55, with a mean follow up of 10.7 years. MAIN RESULTS: Smoking, hypertension (> or = 160/95 mm Hg or treatment), hyperlipidaemia (cholesterol > or = 6.5 mmol/l or triglycerides > or = 2.3 mmol/l), diabetes, low occupation and education levels were significantly more common among women who experienced a fatal or nonfatal myocardial infarction during the follow up (n = 104) than in other women (n = 9247). Exposure to smoking, hypertension and hyperlipidaemia showed substantial differences between groups defined in terms of education, occupation and marital status. The association between low occupation and myocardial infarction remained statistically significant after adjustments for several potential confounders (RR = 2.6, 95% CI 1.1, 6.0). Single women had similarly higher adjusted mortality rates than married women (RR = 1.4, 95% CI 1.1, 1.8). When other major risk factors were taken into account, the relative risk for mortality and myocardial infarction associated with smoking was 2.6 (95% CI 2.0, 3.4) and 7.8 (95% CI 4.4, 13.9), respectively. CONCLUSION: In this urban female population, short education and low occupation level were both associated with an increased prevalence of smoking, hypertension, hyperlipidaemia and diabetes. Low occupation level increases the rate of cardiac events caused by exposure to these four risk factors.

Adult↗