Fluoride Update / Update Fluorid

This article will provide an overview of the principles and modes of action of fluorides in oral care products, followed by a brief outline of the history and current situation regarding salt fluoridation in Switzerland. Recommendations for the use of fluoridated oral care products, current research results on the use of fluoride-containing dental care products and controversies related to fluorides are presented. Finally, the changes in fluoride concentration for children's toothpastes in Europe and the corresponding implementation in Switzerland as well as changes regarding the use of fluoride in school dentistry are discussed.

The Impact of Orthodontic Bands on the Marginal Periodontium of Maxillary First Molars: A Retrospective Cross-Sectional Radiographic Analysis.

AIM: Available information on the effect of orthodontic treatment on crestal alveolar bone levels measured in radiographs is contradictory. The aim of this study was to compare the alveolar bone level and periodontal ligament space of banded upper first molars to untreated controls. MATERIALS AND METHODS: This retrospective cross-sectional radiographic study investigated alveolar bone levels of upper first molars of an orthodontic test group and an untreated control group of comparable age (15-16.25 years), using existing bitewing radiographs.Eighty-six individuals were included in each group. Three parameters were measured mesially and distally on both sides of the patient as follows: I) Alveolar Bone Level (ABL): measured as the distance between the cemento-enamel junction and the alveolar crest, II) the Periodontal Ligament Space (PLS): measured as the most coronal distance between the alveolar crest and the tooth surface, and III) angle between the lines (alveolar crests mesial and distal) and (cemento-enamel junction mesial and distal). RESULTS: The mean duration of the orthodontic treatment in the test group was 2.5 years. The periodontal ligament space was statistically significantly wider on mesial areas of right molars (mean 0.2 mm, p<0.01), but there was no statistically significant difference found in the three other areas (distal part of the right molar, mesial and distal parts of the left molar). There was a statistically significant mean alveolar bone loss in the right and left mesial areas, respectively accounting for 0.3 mm (p<0.001) and 0.2 mm (p<0.01). No statistically significant alveolar bone loss was measured on the distal surfaces of the upper molars. The angle was wider on both sides for the test group (right p<0.001 and left p<0.05). CONCLUSIONS: A significant alveolar bone loss on the mesial tooth surface of upper first molars after orthodontic treatment was found with concurrent different levelling angles in the test group. On all other sites, no statistically significant changes were found. There was some minimal statistical significant alveolar bone loss after finishing treatment in patients who had orthodontic bands placed on their maxillary 1st molars, but no clinical significance was found.

Caries experience in 7-, 12-, and 15-year-old schoolchildren in the canton of Basel-Landschaft, Switzerland, from 1992 to 2011.

OBJECTIVES: To investigate the changes in caries experience and prevalence among schoolchildren of the canton of Basel-Landschaft, Switzerland, over the course of 20 years. METHODS: A random sample of either schoolchildren aged 7, 12, and 15 years (in 1992) or aged 12 and 15 years (in 1997) or their respective school classes (2001, 2006 and 2011) was selected so that approximately 10% of schoolchildren could be examined. The children's dmft and DMFT scores were determined according to the WHO methodology and analyzed using cluster-adjusted ordinary multiple linear regression modeling. RESULTS: For all age groups, the respective dmft/DMFT values decreased steadily from 1992 to 2006 but increased again in 2011. However, the observed differences were not statistically significant over the examination years from 2001 to 2011. Schoolchildren with a migrant background had approximately two- to threefold higher dmft/DMFT values. CONCLUSIONS: In the years from 1992 to 2001, a steady decline in caries was observed in all age groups of schoolchildren examined in the canton of Basel-Landschaft. However, in the subsequent 10 years, this decline has leveled off. The mean dmft/DMFT values are comparable to those in other parts of Switzerland. Migrants are a caries-risk group; the mean dmft/DMFT values were higher in schoolchildren with a migrant background than in the comparable Swiss children.

Survey on oral hygiene measures for intubated patients in Swiss intensive care units.

Five to ten percent of all hospitalized patients are treated in intensive care units. The risk of nosocomial infections is inherent in the latter, especially in cases of intubation. In this context, impaired oral hygiene may play a pivotal role. Therefore, the purpose of this survey among representative Swiss intensive care units was to assess the standards and measures taken in this patient collective with reduced oral hygiene. To this end, a questionnaire was sent to 25 institutions which represented all A- and University hospitals in Switzerland as well as all accredited intensive care units in the canton of Zurich according to the register of the Swiss Society of Intensive Medicine. Intensive care units from pediatric departments were excluded. Twenty-one questionnaires were received and evaluated (84%). Only one quarter of all respondents reported having protocols available for preventing ventilation-associated pneumonia (VAP). Systemic antibiotic regimens were never performed. Ninety percent reported cleaning the patients' teeth mechanically with a toothbrush. Sixty-seven percent used chlorhexidine as a disinfectant (81% in liquid form). Seventy-five percent of the responding hospitals performed routine oral cleaning procedures three times a day (90% immediately after intubation). In summary, oral prophylaxis was neither standardized nor consistently implemented in the evaluated Swiss intensive care units of the responding hospitals. Only a small proportion had protocols available for preventing VAP, which is in accordance with similar surveys conducted in the US and Europe. Additional and improved measures have to be determined to confirm or optimize prophylactic oral strategies and to create standards and guidelines for this at-risk patient collective.

The prevalence of approximal caries in patients after fixed orthodontic treatment and in untreated subjects: a retrospective, cross-sectional study on bitewing radiographs.

OBJECTIVE: The aim of this retrospective, cross-sectional study was to investigate the prevalence of approximal carious lesions in patients after fixed multibracket therapy and in subjects without orthodontics on bitewing radiographs. MATERIAL AND METHODS: Bitewing radiographs of 104 orthodontically treated patients with fixed multibracket appliances were compared to those of 111 untreated subjects. The individuals in both groups were between 15 and 16.25 years of age when radiographs were taken. The test group with orthodontics was recruited from the archive of the Department of Orthodontics at the University of Zürich. The untreated control group was selected randomly from 16 communities in the Canton of Zürich. The approximal surfaces of the permanent premolars and molars of all subjects were assessed by two calibrated investigators. RESULTS: The average number of enamel lesions in the test group after fixed orthodontic treatment was lower than in the control group (0.57 vs. 1.85, p < 0.001). The same was found for dentin lesions (0.06 vs. 0.49, p < 0.001). The distribution of lesions was similar in both groups. CONCLUSION: Fewer approximal carious lesions were detected in the test group after fixed multibracket appliances than in the age-matched control group without orthodontic treatment.

Clinical and radiographic evaluation of patients receiving both tooth- and implant-supported prosthodontic treatment after 5 years of function.

PURPOSE: The aim of this research was to assess survival and complication rates of tooth- and implant-supported fixed dental prostheses (FDPs) and single crowns (SCs) after 5 years of function in a specific patient population group who underwent comprehensive prosthetic treatment. MATERIALS AND METHODS: This retrospective study included a convenience sample of 52 patients who met specific inclusion and exclusion criteria and were treated during two specific courses as part of the undergraduate curriculum. The patients' prosthodontic treatment comprised 296 tooth-supported and 37 implant-supported SCs together with 76 tooth-supported and 15 implant-supported FDPs. Pre- and posttreatment clinical examinations included screening for biologic and technical complications, probing pocket depth, bleeding on probing (BoP), and plaque control record (PCR) as well as intraoral radiographs. Information was obtained from the patients about dental hygiene and dental visits, treated complications, and patient satisfaction during the observation period. Descriptive statistics were employed. RESULTS: Forty-five patients were followed for a mean observation period of 5.26 ± 0.47 years. The survival rates were 99.0% for tooth-supported SCs, 98.7% for tooth-supported FDPs, and 100% for implant-supported FDPs and SCs. Loss of vitality was observed in 2.9% of all abutment teeth deemed to be vital initially. Endodontic complications occurred in 5% and root fracture in 2.5% of nonvital abutment teeth. Caries was found in 0.4% of abutments. No framework or implant fractures were observed, but fracture of the veneering ceramic affected 3.8% of FDPs. The mean BoP was 21.5% ± 9.9%, and the mean PCR was 22.8% ± 16.5%. A high satisfaction rating was provided by 82.2% of patients. CONCLUSIONS: High survival and relatively few complication rates were observed for all prescribed FDPs over the observation period.

Dental visits, oral hygiene behaviour, and orthodontic treatment in Switzerland.

Since the first survey in 1992/93, the Swiss Health Survey (SHS) has been repeated every 5 years (1997, 2002 and 2007). In the present study, dental visits (dental care utilisation within the last 12 months), oral hygiene measures and the frequency of orthodontic treatments in the Swiss population in 2002 were examined and dental visits were compared with the years 1992/93, 1997 and 2007. Weighted data were analysed regarding different sociodemographic factors. From 1992 to 2002, dental visits among the 15-74-year-old declined continuously (1992/93: 70%, 1997: 66%, 2002: 63%), whereas in 2007 a slight increase (66%) was documented. In the survey from 2002, a large proportion (74%) of the population stated to clean their teeth or prostheses several times a day, predominantly with a manual toothbrush, whereas 28% applied an electric toothbrush and almost half of the respondents also used dental floss or toothpicks. Fewer visits and less intensive oral hygiene measures were observed among the elderly, men, weak social strata, smokers, persons with more than 8 missing teeth and in the group with removable dentures. Almost a quarter of the population had orthodontic treatment with the highest proportion among the 15-24-year-old (56%).

Caries risks and appropriate intervals between bitewing x-ray examinations in schoolchildren.

Short intervals between bitewing examinations favor the timely detection of lesions on approximal surfaces. Long intervals reduce the exposure to radiation. Thus, the question arises which intervals between bite-wing examinations are appropriate. The length of intervals between bitewing examinations should be adapted to the caries risk on approximal surfaces of molars and premolars. In order to estimate the caries risk in the Swiss school population, longitudinal data of 591 schoolchildren from the Canton (County) of Zurich were analyzed. These schoolchildren had been examined at 4-year intervals. The proportion of 7-year-olds with caries increment on approximal surfaces within 4 years was 7.1%, i.e., the caries risk in the population was 7.1%. In the 11-year-olds, the caries risk was 17.60%. Seven-year-olds without caries experience on selected approximal surfaces had a low caries risk of 2.2%. However, 7-year-olds with caries experience on selected approximal surfaces had a high risk of 24.2%. The same applied to 11-year-olds: those without caries experience had a low risk (7.5%), and those with caries experience had a high risk (38.5%). For the 7-year-old schoolchildren without any caries experience, an x-ray interval of 8 years is proposed. For the 7-year-old schoolchildren with caries experience, an x-ray interval of 1 year is proposed.

Further caries decline in Swiss recruits from 1996 to 2006.

Previous investigations showed a steady decline of the caries experience. The purpose of this study was to determine the caries experience of Swiss recruits in 2006 and to compare it to that of 1985 and 1996. The results of a parallel investigation which dealt with the periodontal health of the same recruits have already been published (Röthlisberger et al. 2007). Investigations on recruits in 1970 (Curilovic et al. 1972) and 1974 (Curilovic et al. 1980) used another methodology. Therefore, they were not included here for comparison.

Assessment of dental fluorosis prevalence in Swiss populations.

In 1996 and 2006, recruits of the Swiss army participated in a dental survey. Similarly in 1995/96 and 2004/05, randomly selected schoolchildren from 16 rural communities of the Canton of Zurich participated in a dental survey. As part of these surveys, color slides were taken of the incisor teeth of all recruits, as well as of third and fourth grade schoolchildren. The slides (N = 2049) were examined for the presence of fluoride-associated enamel opacities (FOP), using the Thyl-strup-Fejerskov (TF) index. Two examiners (A and B) assessed all slides. The examiners were blind as to the year of survey. Examiner A recorded prevalences of FOP between 18% and 27% depending on population; examiner B recorded prevalences between 7% and 12%. The examiners' influence on the estimation of the prevalence was obvious. The prevalences reported should, therefore, be considered as rough estimates. FOP of TF score 2 were only observed in approximately 1% of the participants. One examiner recorded a TF score 3 in a single individual. FOP therefore are not a cosmetic problem and certainly not a public health concern. The prevalence of FOP decreased slightly during observation period I (recruits born 1975-77 vs 1985-87) and period II (school children born 1985-87 vs 1994-96). However, the decline was statistically supported in only one instance (Period I, Examiner B).

Changes in dental caries in Zurich school-children over a period of 45 years.

In 16 rural communities of the Canton of Zurich, school-children of all age groups participated in dental examinations conducted at intervals of 4 years since 1963/64. The same standardised method was used throughout the entire period. This study documents the caries experience over a period of 45 years. From 1964 to 2009, the DM*FT per 14-year-old child fell from 12.50 to 1.31, corresponding to a caries reduction of 90%. The caries experience in 8-, 10- and 12-year-olds decreased by 90% to 92%. From 1964 to 2009, the "Significant Caries Index" (the mean DM*FT in the third of 12-year-olds with the highest DM*FT values) fell from 13.09 to 2.20, corresponding to a caries reduction of 83%. The observed caries decline was unexpectedly high. The effect of fluorides may explain a caries reduction of roughly 50%. A large part of the decline, however, remains unexplained. Possible causes are discussed in this paper.

[Early childhood caries--facts and prevention]. / Kleinkinderkaries--Fakten und Vorbeugung.

In 2003, 771 randomly selected two-year-old children from the town of Zurich were examined. Teeth with carious cavities were observed in 12.6% of the children. Caries including initial (not yet cavitated) lesions was seen in 25.3% of children. Caries prevalence was strongly associated with immigrant background. Caries was found in 7.5% of Swiss children and in 38.5% of children from ex-Jugoslavia. 5% of children of mothers born in Switzerland, and 17.4% of children of mothers not born in Switzerland showed caries. The average number of teeth with carious lesions in children with caries was 4.3 irrespective of immigrant or Swiss background. This finding suggests that all kids with caries had similar risk behaviours. Multivariate logistic regressions elucidated the behavioural components associated with caries. The presence of plaque and the use of a night-time bottle proved to be the strongest predictor variables for caries. Frequent drinking of sugared non-milk drinks, age and no pacifier use were further risk indicators in children of foreign-born mothers. A significant improvement of oral health of small children can be achieved by a concerted action of child welfare consultants, paediatricians and carers of day-nurseries. The primary goal is to convince parents to actively participate in preserving dental health of their offsprings. The following recommendations should be adhered to: 1. Parents should brush the teeth of the children daily, using a fluoridated children-toothpaste starting the very day of the appearance of the first milk tooth. 2. At the age of 12 months, the bottle should be replaced by a cup and the continuous use of a nursing bottle while falling asleep and during the night should absolutely be avoided. 3. Children should primarily be offered water and milk as a beverage. A first dental inspection is due at the age of two years.

Changes in oral health over a 10-yr period in Switzerland.

The Swiss Health Surveys are conducted every 5 yr, and alternate surveys contain information on oral health. Worldwide the population is ageing and oral health is improving. The aim of this study was to identify if these trends are continuing in a relatively affluent society with low levels of edentulousness. Participants in the 1992 and 2002 surveys completed a written questionnaire including items on oral health (response rates 75% and 86% respectively). Data were weighted and bivariate analyses were performed to calculate the average number of missing teeth and the prevalence of different prosthetic dental restorations for each cohort. Over the 10-yr period the proportion of subjects retaining all natural teeth increased, and the mean number of teeth increased, on average, by 1.3. Among those who required prosthetic dental restorations, fixed restorations increased and complete denture use was reduced. Strikingly, 4.4% of this sample reported having oral implants in 2002. Greater numbers of missing teeth and a higher prevalence of use of removable prostheses were still seen in women, in those who had only completed compulsory education, in subjects from families with low income, in those who smoke, and in those who were overweight, in 2002.

Dental fluorosis in salt fluoridation schemes.

The prevalences of fluoride-associated opacities (FOP) and nonfluoride-associated opacities (non-FOP) were assessed in two cantons of Switzerland with different salt fluoridation schemes. In the Canton of Zurich 305 schoolchildren from eight communities (age 9-10) were examined in 1995 and 900 children from one community (age 8-16) in 2002. In the Canton of Glarus 144 schoolchildren from 14 communities (age 9-10) were examined in 1996. In the Canton of Zurich 84% of the children used fluoridated domestic salt (250 ppm F) in the first five years of their life (questionnaire for parents 1995). In the Canton of Glarus, the corresponding value was 87%. In addition, about half of the bread samples in the Canton of Glarus showed an increased fluoride content (> 3 ppm F). Standardized photographs were taken of incisors dried with compressed air (15 seconds) and assessed using the Thylstrup Fejerskov index. The prevalence of FOP was 21% in eight communities of the Canton of Zurich (1995) and 22% in 14 communities of the Canton of Glarus (1996). No differences were found between these two locations, although fluoride intake was higher in the Canton of Glarus due to fluoridated salt used by bakeries. A recent examination in one community of the Canton of Zurich (2002) showed a lower prevalence of 11%. The prevalences of non-FOP in all locations were between 17% and 23%. The prevalences of FOP were at a low level in Switzerland compared to international studies using the same index. The most plausible explanation for this difference is the widespread use of low fluoride toothpastes (250 ppm F) by children under six. These toothpastes were introduced in 1986 and the consumption increased continuously until 1992. The low FOP prevalence cannot be considered a public health problem and is not perceived as such by the population. It is concluded that the Swiss fluoridation policy of the past two decades was approprate, with caries prevalence in permanent teeth of Swiss schoolchildren being among the lowest globally.

Use of the Significant Caries Index in quantifying the changes in caries in Switzerland from 1964 to 2000.

OBJECTIVES: To follow the changes in the Significant Caries Index (SiC) and the DMFT during the period 1964-2000 in children aged 12 and 15 in the Canton of Zurich. METHODS: Examinations of random samples of children in 16 communities of the Canton were repeated every 4 years from 1964 onwards using the same standards for diagnosing caries. RESULTS: In the 12-year-olds, the children in the low tertile had virtually no DMF-experience from 1980 on. On the contrary, the SiC, based on the children in the highest tertile, decreased until 1996. At the age of 15, the zero-average in the low tertile was reached in 1992 but the SiC continued to decrease until 2000. In the 12-year age group the reduction of the SiC from 1964 to 1996 was 81.3% and for the overall DMFT it was 89.7%. The corresponding reductions for the 15-year-olds, in this case from 1964 to 2000, were 77.0 and 88.4%, respectively. The DMFT-counts in the total samples had substantially higher coefficients of variation than those in the highest tertile. As a consequence, the SiC had relatively smaller confidence intervals than the average DMFT. CONCLUSIONS: The SiC is a very useful measure of dental caries experience. On the basis of the results in the 15-year-old group, the target of an SiC below 5.0 is proposed. The decline of the SiC demonstrates that even in the high-risk children caries experience has been reduced substantially.

Effect of 1000 ppm relative to 250 ppm fluoride toothpaste. A meta-analysis.

PURPOSE: To estimate the overall effect of 1000 ppm F relative to 250 ppm F toothpaste. METHODS: Experimental caries increment studies from the dental literature, which compared 1000 ppm with 250 ppm fluoride toothpastes, were summarized using meta-analytic methods. RESULTS: The overall caries reduction of 1000 ppm F relative to 250 ppm F paste was estimated to be 0.142 (95%-CL: 0.074-0.210) when applying a fixed effects model and 0.129 (95%-CL: 0.012-0.230) when applying a random effects model. CLINICAL SIGNIFICANCE: The present analysis found slightly lower caries increments (14%, 13%) in children using 1000 ppm F toothpastes compared to children using 250 ppm F pastes. On the other hand, the use of 1000 ppm F pastes is associated with dental fluorosis. Considering these effects it seems justifiable to the authors to keep the use of 250 ppm F pastes for preschool children in Switzerland.

[Caries prevalence among students in the city of Winterthur: comparison with the city of Zurich and 16 communities in the canton of Zurich]. / Kariesprävalenz von Schülern der Stadt Winterthur: Vergleiche mit der Stadt Zürich und 16 Zürcher Landgemeinden.

The aim of the present survey was to assess the caries prevalence in schoolchildren of the city of Winterthur in the year 2002. A simple random sample of 1000 schoolchildren was drawn. 65% of the children participated in the standardized investigation. The mean DMFT-value (permanent dentition) in 12-year-olds was 1.0 and was on a low level in a European comparison. The mean dmft-value (deciduous dentition) in 7-year-olds was 2.0. From 1971 to 2002, DMFT-values decreased by about 80% in Winterthur. The dmft-values decreased by about 60%. The splitting by nationality revealed a high caries prevalence in schoolchildren from the former Yugoslavia and Albania. A multivariate analysis showed no significant differences in caries prevalence between the schoolchildren of the city of Winterthur and other communities of the canton of Zurich.

[Caries prevalence among 5-year-olds in the city of Winterthur in the year 2001]. / Kariesprävalenz von 5-Jährigen der Stadt Winterthur im Jahre 2001.

The aim of the present study was to assess the caries prevalence of 5-year-olds in the city of Winterthur in 2001. By simple random sampling 350 children were selected. Two-hundred-and-ninety-one of the children (83%) participated. The mean dmft-value was 2.42; of that 1.87 were untreated carious teeth (dt). Forty-five per cent of the children showed caries in the deciduous dentition. Twenty-one per cent of the children had high caries experience (5 or more dmft). Twenty-one per cent showed caries in deciduous incisors. In 4% of the children primary molars were missing. Splitting by nationality revealed great differences. On average, the Swiss children had 1.70 dmf-teeth; the ex-Yugoslavian and Albanian children had 7.84 dmf-teeth. Fifteen percent of the Swiss children had high caries experience; in contrast 65% of the ex-Yugoslavian and Albanian children had high caries experience.

[Caries prevalence among students in 16 Zurich districts in the years 1992 to 2000]. / Kariesprävalenz von Schülern in 16 Zürcher Landgemeinden in den Jahren 1992 bis 2000.

Standardized dental examinations of schoolchildren were regularly carried out since 1964 in 16 rural communities of the Canton of Zurich. In 1964, there were no 14-year-old schoolchildren free from caries; in the Nineties about half of the 14-year-olds had a caries-free permanent dentition (DMFT = 0). From the year 1992 to 2000, the caries prevalence (DMFT) of 14-year-olds decreased once again, by 31%. The pit and fissure caries prevalence (DFS) of 12- and 14-year-olds decreased by 28% and 37%, respectively. In 2000, the mean DMFT-value of the 12- and 14-year-old schoolchildren was 0.90 and 1.27 respectively. In 1964, only few 7-year-old schoolchildren were caries-free; in the Nineties about half of the 7-year-olds had a primary dentition without caries. From the year 1992 to 2000, caries prevalence (dmft) in 7-, 8- and 9-year-olds increased by 64%, 22% and 31%. In 2000, the mean dmft-value of all 7-year-old schoolchildren was 2.45. The Swiss schoolchildren had 1.79 dmft; the schoolchildren from former Yugoslavia and from Albania had 6.89 dmft and those of other nations had 3.37 dmft. Possible reasons for the continuous caries decrease in the permanent dentition and the increase in the primary dentition are discussed. Additional measures in order to improve the situation in the primary dentition are proposed.

An example of complex modelling in dentistry using Markov chain Monte Carlo (MCMC) simulation.

BACKGROUND: In the usual regression setting one regression line is computed for a whole data set. In a more complex situation, each person may be observed for example at several points in time and thus a regression line might be calculated for each person. Additional complexities, such as various forms of errors in covariables may make a straightforward statistical evaluation difficult or even impossible. OBJECTIVE AND METHOD: During recent years methods have been developed allowing convenient analysis of problems where the data and the corresponding models show these and many other forms of complexity. The methodology makes use of a Bayesian approach and Markov chain Monte Carlo (MCMC) simulations. The methods allow the construction of increasingly elaborate models by building them up from local sub-models. The essential structure of the models can be represented visually by directed acyclic graphs (DAG). This attractive property allows communication and discussion of the essential structure and the substantial meaning of a complex model without needing algebra. EXAMPLE: After presentation of the statistical methods an example from dentistry is presented in order to demonstrate their application and use. The dataset of the example had a complex structure; each of a set of children was followed up over several years. The number of new fillings in permanent teeth had been recorded at several ages. The dependent variables were markedly different from the normal distribution and could not be transformed to normality. In addition, explanatory variables were assumed to be measured with different forms of error. Illustration of how the corresponding models can be estimated conveniently via MCMC simulation, in particular, 'Gibbs sampling', using the freely available software BUGS is presented. In addition, how the measurement error may influence the estimates of the corresponding coefficients is explored. It is demonstrated that the effect of the independent variable on the dependent variable may be markedly underestimated if the measurement error is not taken into account ('regression dilution bias'). CONCLUSION: Markov chain Monte Carlo methods may be of great value to dentists in allowing analysis of data sets which exhibit a wide range of different forms of complexity.