Efficacy of dental prophylaxis (rubber cup) for the prevention of caries and gingivitis: a systematic review of literature.

BACKGROUND: The purpose of this systematic review was to assess the efficacy of routine dental prophylaxis applied before professionally applied topical fluoride (PATF) or at a regular recall visit in the prevention of caries or gingivitis. TYPES OF STUDIES REVIEWED: Ovid MEDLINE and its allied versions; CINAHL; Cochrane Library; EMBASE; Health and Psychosocial Instruments; HealthSTAR; International Pharmaceutical Abstracts; and ACP Journal Club were searched for English and Human articles from 1966 to 2007 for original in vivo English publications assessing rubber cup dental prophylaxis. In vitro studies, case series, case reports or letters to editors (not containing primary data), editorials, review articles and commentaries were excluded but were read to identify any potential studies. RESULTS: One hundred and eighty-nine articles were searched for relevancy resulting in six original studies that met our inclusion criteria. There was a unanimous agreement in four studies that a dental prophylaxis is not warranted before a PATF for caries prevention in children. A generalisation on dental prophylaxis before PATF cannot be applied to adolescents and adults. Available evidence (two other studies) fails to demonstrate any benefit in the prevention of gingivitis from further dental prophylaxis at interval used for recall examinations. CLINICAL IMPLICATION: To prevent caries in children, dental prophylaxis need not be provided either at a recall visit or before PATF. Dental prophylaxis at intervals of four months or more is not justified for the prevention of gingivitis in the general population.

The peopling of New Guinea: evidence from class I human leukocyte antigen.

This study utilizes newly developed direct DNA typing methods for human leukocyte antigens (HLA) to provide new information about the peopling of New Guinea. The complete polymorphism of eight Melanesian populations was examined. The groups included were highlanders, northern and southern highlands fringe populations, a Sepik population, northern and southern coastal New Guinea populations, and populations from the Bismarck Archipelago and New Caledonia. The study concluded that, based on HLA and other evidence. Melanesians are likely to have evolved largely from the same ancestral stock as Aboriginal Australians but to have since differentiated. Highlanders are likely to be descendants of earlier migrations who have been isolated for a long period of time. Northern highlands fringe and Sepik populations are likely to share a closer common ancestry but to have differentiated due to long term isolation and the relative proximity to the coast of the Sepik. Southern fringe populations are likely to have a different origin, possibly from the Gulf region, although there may be some admixture with neighboring groups. Coastal populations have a wider range of polymorphisms because of the genetic trail left by later population movement along the coast from Asia that did not reach Australia or remote Oceania. Other polymorphisms found in these populations may have been introduced by the movement of Austronesian-speaking and other more recent groups of people into the Pacific, because they share many polymorphisms with contemporary southeast Asians, Polynesians, and Micronesians that are not found in highlanders or Aboriginal Australians. There is evidence suggestive of later migration to Melanesia from Polynesia and Micronesia.

Toothbrushing competency among high-risk grade one students: an evaluation of two methods of dental health education.

OBJECTIVE: To evaluate the effectiveness of two methods of dental health education (DHE) for improving toothbrushing competency among grade one students at high risk for dental diseases. METHODS: Fifty elementary schools in the former city of North York, Ontario, Canada, were assigned to one of two groups. In one group, students received a classroom-based DHE lesson that was reinforced by two small group sessions (n = 243). In the other group, students received only a single classroom-based DHE lesson (n = 206). Trained examiners assessed 11 toothbrushing skills at pre- and postintervention. RESULTS: At the preintervention test, few significant differences were found between the groups and many students did not display competency in fundamental oral health skills, such as placing a toothbrush at the gum line. Following DHE interventions, students in both groups demonstrated improvements in most skills. A significantly higher proportion of students who received both classroom and small group sessions displayed gains in competency in three skills, compared to students receiving only a classroom lesson. These skills were brushing anterior lingual surfaces, brushing posterior lingual surfaces, and brushing all areas in a routine fashion. Students receiving only a classroom session did not display greater improvements in any skill areas compared to "classroom plus small group" students. Some students in both groups still lacked fundamental skills at the end of the DHE program. CONCLUSIONS: While one must exercise caution in interpreting the results due to several methodologic limitations, findings suggest that for high-risk grade one students, a classroom-based lesson combined with small group sessions is a more effective method of improving toothbrushing skills compared to a single classroom-based lesson.

Landau-level spectroscopy of a two-dimensional electron system by tunneling through a quantum dot.

A single InAs self-assembled quantum dot is incorporated in the barrier of a tunnel diode and used as a spectroscopic probe of an adjacent two-dimensional electron system from the Fermi energy to the subband edge. We obtain quantitative information about the energy dependence of the quasiparticle lifetime. For magnetic field B, applied parallel to the current, we observe peaks in the current-voltage characteristics I(V) corresponding to the formation of Landau levels. Close to filling factor nu=1 we observe directly the exchange enhancement of the Lande g factor.

Imaging the electron wave function in self-assembled quantum dots.

Magnetotunneling spectroscopy is used as a noninvasive and nondestructive probe to produce two-dimensional spatial images of the probability density of an electron confined in a self-assembled semiconductor quantum dot. The technique exploits the effect of the classical Lorentz force on the motion of a tunneling electron and can be regarded as the momentum (k) space analog of scanning tunneling microscopy imaging. The images reveal the elliptical symmetry of the ground state and the characteristic lobes of the higher energy states.

Oral hygiene knowledge of high-risk Grade One children: an evaluation of two methods of dental health education.

The effectiveness of two methods of dental health education (DHE) for improving oral hygiene knowledge among high-risk Grade One students was evaluated. Fifty elementary schools in the former City of North York, Canada were assigned to one of two groups. In one group, students received a classroom-based DHE lesson which was reinforced by two small-group sessions (n=243). In the other group, students received only a single classroom-based DHE lesson (n=206). After DHE interventions, students in both groups displayed improved knowledge for most oral hygiene questions (e.g., when should you throw your toothbrush away?). However, for several questions, a significantly higher proportion of "classroom plus small-group sessions" students displayed improved knowledge compared to students receiving only a classroom lesson. These items included: awareness that cavity prevention and removal of germs are two purposes of oral hygiene; and knowledge that teeth help people to eat and talk. Results suggest a classroom-based lesson combined with small-group sessions is a more effective method of improving oral hygiene knowledge among high-risk Grade One students compared to a single classroom-based lesson.

Low-resolution phase extension using wavelet analysis.

A method to extend low-resolution phases is presented which uses histogram matching not only of the electron density, but also of histograms obtained from the different levels of detail provided by the wavelet transform of the electron density. Statistical values for the wavelet coefficients can be predicted and depend only on the resolution and solvent content. Therefore, new details can be added to an electron-density map by matching the values of the wavelet coefficients to those predicted for an increased resolution. The positions of the new details are also guided by the diffraction pattern. In this way, the resolution can be increased gradually; on a number of trial structures of different size, solvent percentage and space group, it has been possible to extend the phasing from 10 A to around 6-7 A.

Wavelet analysis of electron-density maps.

The wavelet transform is a powerful technique in signal processing and image analysis and it is shown here that wavelet analysis of low-resolution electron-density maps has the potential to increase their resolution. Like Fourier analysis, wavelet analysis expresses the image (electron density) in terms of a set of orthogonal functions. In the case of the Fourier transform, these functions are sines and cosines and each one contributes to the whole of the image. In contrast, the wavelet functions (simply called wavelets) can be quite localized and may only contribute to a small part of the image. This gives control over the amount of detail added to the map as the resolution increases. The mathematical details are outlined and an algorithm which achieves a resolution increase from 10 to 7 A using a knowledge of the wavelet-coefficient histograms, electron-density histogram and the observed structure amplitudes is described. These histograms are calculated from the electron density of known structures, but it seems likely that the histograms can be predicted, just as electron-density histograms are at high resolution. The results show that the wavelet coefficients contain the information necessary to increase the resolution of electron-density maps.

The use of wavelet transforms in low-resolution phase extension.

A method to extend low-resolution phases has been developed using histogram matching not only of the electron density itself but also of histograms obtained from the different levels of detail provided by the wavelet transform of the electron density. It is shown that the method can extend phases from 10 A to around 6-7 A on a wide range of trial structures differing in size, space group and solvent content. This level of phase extension can improve the electron-density map from little more than a molecular envelope to one in which secondary structure can often be identified.

A system of diagnostic codes for dental health care.

OBJECTIVES: We set out to develop and implement a system of diagnostic codes for use in the computerized management information system of the Community Dental Services of the North York Public Health Department. METHODS: We received staff input on common diagnoses, reviewed other diagnostic systems and established criteria for an ideal coding system. The codes are consistent with the format of other classification systems used in dental management information in Canada. They were implemented in 1997-98. RESULTS: We developed a system of four-digit, numeric codes for dental diagnoses. The diagnostic codes are specific at the level of the patient, consistent with current evidence on the natural history and classification of diseases, consistent with conventional measures of oral conditions, and fit the paradigm of the Canadian system of treatment codes. In the first year, 91 percent of 6,740 patients had at least one diagnosis, with a mean of 2.5 per patient. The five most common diagnoses were smooth surface caries, pit and fissure caries, calculus, teeth with deep fissures, and gingivitis. CONCLUSIONS: We have developed a coding system for dental diagnoses that has achieved high use and provided more accessible information on the conditions seen by staff dentists.

Miscellaneous algorithms for density modification.

Various algorithms are described, developed for the dm density modification package, which have not been described elsewhere. Methods are described for the following problems: determination of the absolute scale and overall temperature factor of a data set, by a method which is less dependent on data resolution than Wilson statistics; an efficient interpolation algorithm for averaging and its application to refinement of averaging operators; a method for the automatic determination of averaging masks.

Reducing variability in treatment decision-making: effectiveness of educating clinicians about uncertainty.

The objective of this study was to investigate whether or not education about the concept of uncertainty reduced variability in treatment decision-making. Three small groups of dentists in North York, Canada were asked to make restorative treatment decisions about simulated bitewing radiographs. They subsequently took part in a seminar about variations in perception and judgement and were given explanations of sensitivity, specificity and receiver operating characteristic (ROC) curve analysis. A repeat reading of the radiographs was then performed by both test and control groups. Results indicated that the intervention increased the accuracy, and decreased the variability of dentists' restorative treatment decisions. Kappa statistics were 0.33, 0.34 and 0.31 before the seminar, and 0.40, 0.43 and 0.41 after the seminar. Standard errors for kappas were 0.06, 0.05 and 0.05 before the seminar, and 0.02, 0.02 and 0.05 after the seminar. The area under the ROC curve was 0.7136 before the seminar and 0.7835 after the seminar. The data demonstrate that the dentists' decisions were less variable and more accurate following the educative intervention. This study suggests that there is potential for improving consistency and accuracy in clinical decision-making through education in probabilistic reasoning.

Health years equivalents as a measurement of preferences for dental interventions.

OBJECTIVE: To test the feasibility and importance of measuring preferences among treatment choices using Healthy Years Equivalents (HYE). DESIGN: Development of scenarios for alternative approaches to caries treatment. Completion of category rating and standard gamble questions elicited in personal interviews. SETTING: The provision of dental care to children in a public-funded dental health clinic. PARTICIPANTS: Random sample of the adult population of Hamilton, Ontario. MAIN OUTCOME MEASURES: The percentage of the sample unable to complete the interviews, time taken to perform interviews, ease of understanding of interviews, correlation between rank ordering and HYE scores. RESULTS: Ninety-six per cent of the sample were able to complete the HYE exercise. Inconsistencies between HYE scores and rank orders implying preference reversal occurred in 6% of those completing HYE scores for the two scenarios. The additional time taken by the HYE was of the order of 17 minutes but increased with the age of the subject. Where problems occurred, they were related to the method of measurement or the sensitivity of the chosen scale as opposed to additional requirements of the HYE. There was some evidence that HYEs and QALYs produced different scores even in the context of chronic constant health states. CONCLUSIONS: HYEs are a feasible and important practical method of measuring preferences among interventions. Alternative utility-based approaches, such as willingness to pay, may be required to detect differences in modest improvements in temporary health states.

Oral health status and treatment needs of Canadian adults aged 85 years and over.

In an oral health survey, 1375 adults aged 85 and older were examined in North York, Canada. Only 31% of dentate nursing home residents and 47% of dentate independently living subjects had received dental care in the year previous to examination. The overall prevalence of edentulism was 66%, and about 80% of subjects wore at least one denture. Of the dentate subjects, over 60% had untreated decay, and 47% of nursing home residents had untreated root decay. Regarding clinically defined treatment needs, high levels of unmet need were identified in subjects from both types of residences. Among nursing home residents, about 45% of dentate subjects required tooth extraction, and 56% required prosthodontic treatment. Although only 27% of dentate independently living residents required tooth extraction, over 60% needed restorative treatment. Higher prevalence of both untreated decay and unmet treatment needs was associated with lower utilization of dental care for dentate subjects. For edentulous subjects, prosthetic treatment was required by 70% of nursing home residents and by 51% of independently living subjects. These results indicate that, for both nursing home and independently living residents, dental diseases and treatment needs continue through out the lifespan.

A survey of general dentists in Ontario, Part II: Knowledge and use of topical fluoride and dental prophylaxis practices.

A mail questionnaire was used to assess variations in the knowledge and practices of Ontario dentists with respect to topical fluoride and prophylaxis procedures. The questionnaire was answered by 1,276 general dentists. A high percentage (72 to 83 per cent) of respondents identified six months as the optimal time interval at which both procedures should be repeated for all patients under 19 years of age. Relatively few dentists (< 10 per cent) indicated that there should be no specific time interval for re-treatment (i.e. that it should be individually selected). The respondents' preventive knowledge was found to be deficient in two areas: few dentists (16 per cent) knew that it is not necessary to provide a prophylaxis prior to topical fluoride application to achieve maximum caries protection; and most dentists overestimated the speed of caries progress from outer enamel to the dentinoenamel junction (DEJ) in both primary (83 per cent) and permanent (82 per cent) approximal tooth surfaces. In bivariate analysis, three variables were found to be consistently and significantly related to optimal time intervals selected for both topical fluoride application and prophylaxis procedures: year of graduation from dental school; level of hygienist employment; and percentage of patients with private insurance. Multivariate analysis also identified three significant variables: year of graduation from dental school; level of dental hygienist employment; and practice business. Continuing education courses are suggested as a means of updating dentists' knowledge regarding preventive services. Studies are needed to determine the extent to which recent recommendations regarding the professional application of topical fluorides have been followed.

A survey of general dentists in Ontario, Part I: Sealant use and knowledge.

This study assessed the use of pit and fissure sealants by Ontario dentists, as well as variations in the knowledge and practices of this population with respect to certain aspects of the preventive technique. A mail questionnaire on dental practices and knowledge was answered by 1,276 general dentists in Ontario. Most dentists (90 per cent) provided sealants to their patients, and reported using sealants on an average of 45 per cent of their patients between the ages of six and 16 years. While most dentists knew that sealants have been proven effective in preventing caries (90 per cent), many incorrectly believed that sealants are cost-effective to apply to both primary molars and permanent premolars (40 per cent and 68 per cent respectively). Bivariate analyses showed that many of the reported characteristics are statistically significant. The variables that were consistently associated with sealant use include: knowledge of the effectiveness and cost-effectiveness of sealants; year of graduation from dental school; level of dental hygienist employment; and continuing education participation. Although multivariate analyses identified many of these variables as statistically significant, only a moderate amount of the variation in sealant use for patients aged six to 16 was explained (R2 = 0.22). Due to misinformation about the cost-effectiveness of sealants, some dentists may overuse them in certain instances. Conversely, misinformation about the effectiveness of sealants and the risk of further decay after sealant placement has resulted in some dentists under-utilizing them. Continuing education courses are needed to update dentists' knowledge and beliefs regarding dental sealants. In addition, dentistry's professional bodies should develop clinical practice guidelines to aid dentists in their treatment planning decisions.

Developing evidence-based programme guidelines for children's dental care in a dental public health unit in Ontario, Canada.

The North York Public Health Department operates a school-based dental care programme. Dental care providers are expected to follow guidelines in order that the programme shall achieve the best outcomes for the clients served. A model is described by which published evidence informs the guideline development process. The process is considered to require knowledge of the epidemiology of dental disease in the target population; skills in collecting, critically appraising and summarising the scientific literature; working with internal and external advisory panels to write the guidelines; disseminating results and assessing both compliance and health outcomes. This work is one example of a larger trend to evidence-based health care.