Biomedical subjects

L Seppä

Publications and source records attributed to L Seppä.

At least 19 recordsLinked to original sources

PubMed2001

The future of preventive programs in countries with different systems for dental care.

From 1990 onward the decline of caries has leveled off in economically developed countries and the effectiveness of preventive programs seems to have diminished. The aim of this paper is to consider the future of caries prevention in the light of the studies conducted during the past decade. A shift from population-based prevention to a high-risk strategy has been promoted in countries where caries is strongly polarized. In Finland, however, an intensive preventive program targeted to high-risk individuals had little effect on caries increment, which suggests that the utility of a high-risk strategy is questionable. The relative effects of population-based methods have also decreased during the last decades. Although discontinuation of water fluoridation had no effect on caries in Kuopio, Finland, water fluoridation is still effective in countries with a lower level of basic prevention and a less homogenous social structure. From the standpoint of cost-effectiveness, the use of professionally applied fluoride gels has been questioned in children with a low caries rate, and the same is probably true for fluoride varnishes. In countries with a high caries rate, a low level of basic prevention, and an unorganized dental care system any preventive program seems to be effective. The importance of fluoride toothpastes as a cost-effective and feasible method of fluoride delivery is indisputable and will be so in all countries irrespective of the caries level and dental care systems. Population-based dental health education continues to be important, also in the countries where the caries rate has so far been low.

Adolescent↗

PubMed2001

Dental check-up intervals and caries preventive measures received by adolescents in Finland.

OBJECTIVE: The aim was first to estimate the mean length of dental examination intervals and the mean number of preventive procedures in two Finnish towns during the periods of 1990-1992 and 1993-1995. Secondly, to ascertain whether the length of the check-up interval and the intensity of prevention varied according to the caries experience at the beginning of a treatment period. Participants A random sample of all 12- and 15-year-old children was drawn in 1992 and 1995 in the towns of Jyväskylä and Kuopio. METHOD: Oral health records obtained from public dental clinics were used for gathering the data on dental check-ups, DMFT and all preventive and treatment measures during the previous three years. The data were available for 267 and 590 subjects in 1992 and 1995, respectively. RESULTS: For 12-year-old children in 1990-1992, the mean length of check-up interval was 13.0 months in Kuopio and 12.4 months in Jyväskylä, while in 1993-1995 it was 18.1 months and 16.1 months, respectively. Among 15-year-old children in 1990-1992, the mean was 12.3 in Kuopio and 14.7 in Jyväskylä. During the latter period the interval was 1.2 months longer (P<0.05) in Kuopio, but there was no lengthening in Jyväskylä. Fluoride varnish applications, sealants, and instruction in oral hygiene were the most commonly used preventive measures. Practically no other fluoride methods than varnish applications were performed in dental clinics. Prevention seemed to be based mainly on procedures performed by the staff at the dental clinics and less attention was paid to the promotion of self-care. There was very little difference in the mean length of check-up interval and prevention between children who were caries free at the beginning of the treatment period and those with present or past caries experience. CONCLUSION: Between 1990-1992 and 1993-1995, the frequency of dental check-ups and the number of preventive procedures decreased. There was no indication of an increased caries frequency. Prevention appeared to be stereotyped and often had little relevance to the actual needs of the individual patient.

Adolescent↗

PubMed2000

Application of the high-risk strategy to control dental caries.

OBJECTIVE: The aim of this prospective study was to determine whether a child population with low overall caries frequency benefits when prevention is targeted to high-risk individuals. METHODS: Data from clinical examinations and salivary tests were used to assess caries risk in 12-year-olds (n=1465). Children who were regarded as being at high risk of developing caries were randomized into two groups. Half (HRI group) were offered intensive prevention (counseling, F-varnish applications, F-lozenges, sealants, chlorhexidine), and the other half (HRB group) were provided the same basic prevention given to low-risk children (counseling, one F-varnish application/year). A random sample of the low-risk children (LRB) was followed up for the same 3-year period as the high-risk children. The number of children completing the study was 216 in the LRB group, 199 in the HRI group and 174 in the HRB group. RESULTS: The mean (SD) 3-year DMFS increment was 2.0 (2.4), 4.4 (4.7) and 5.1 (5.0) in the LRB, HRI and HRB groups, respectively. Comparison between the LRB and HRB groups revealed that risk assessment was fairly successful in terms of mean DMFS increment. However, 63% of the children in the LRB group developed at least one new lesion (max. 12). CONCLUSIONS: The negligible difference between the HRI and HRB groups implies that intensifying prevention produced practically no additional benefit. By offering all children only basic prevention, virtually the same preventive effect could have been obtained with substantially less effort and lower costs.

Child↗

PubMed2000

Caries in the primary dentition, after discontinuation of water fluoridation, among children receiving comprehensive dental care.

UNLABELLED: The city of Kuopio in central Finland had fluoridated piped water for 33 years, beginning in 1959. Due to strong opposition by various civic groups, water fluoridation was stopped at the end of 1992. There is little information on the consequences of stopping fluoridation in a community with comprehensive dental care for all children and adolescents, who are frequently exposed to different fluoride measures both at home and in the dental office. OBJECTIVES: The aim of this repeated cross-sectional survey was to examine how discontinuation of water fluoridation in Kuopio affected caries in the primary dentition. Changes in the mean dmfs values between 1992 and 1995 in Kuopio were compared to those in Jyväskylä, a low-fluoride community that has repeatedly been used as the reference area for Kuopio. METHODS: In 1992 and 1995, independent random samples of all children aged 3, 6 and 9 years were drawn in Kuopio and Jyväskylä. The total number of subjects examined was 421 in 1992 and 894 in 1995. Calibrated dentists registered caries clinically and radiographically. RESULTS: In all age groups both in 1992 and 1995, the point estimates for mean dmfs values were lower in the non-fluoridated town. In both towns, the observed mean dmfs values were smaller in 1995 than in 1992. CONCLUSION: Despite discontinuation of water fluoridation, no increase of caries frequency in primary teeth was observed in Kuopio within a three-year period.

Child↗

PubMed1999

Human growth differentiation factor 9 (GDF-9) and its novel homolog GDF-9B are expressed in oocytes during early folliculogenesis.

Growth differentiation factor 9 (GDF-9) is a transforming growth factor-beta family member that is required for normal folliculogenesis in female mice, but its role as a regulator of human fertility is still unclear. We determined here by in situ hybridization and immunohistochemical analyses the localization of the GDF-9 messenger ribonucleic acid (mRNA) and protein during human folliculogenesis. The GDF-9 transcripts were not detected in primordial follicles, but they are abundantly expressed in primary follicles in frozen sections of ovarian cortical tissue material obtained at laparoscopic surgery. We raised antipeptide antibodies against GDF-9 and showed by immunohistochemical studies on paraffin sections of whole human ovaries that the GDF-9 protein is most abundantly expressed in primary follicles. We recently demonstrated that a novel GDF-9-related factor, GDF-9B, is coexpressed with GDF-9 during murine folliculogenesis. We now isolated human GDF-9B complementary DNA and genomic clones and report the unusually restricted expression pattern of human GDF-9B. The human GDF-9B transcript can be detected only in the gonads by RT-PCR analysis, and in situ hybridization studies indicate that it is not expressed in small primary follicles but, rather, in the oocytes of late primary follicles. Functional studies using the Xenopus laeuis embryo model indicate that unlike the transforming growth factor-beta family members activin and bone morphogenetic protein-4, neither GDF-9 nor GDF-9B affects mesoderm induction, suggesting that they may use signaling pathways distinct from those well defined for activin and bone morphogenetic protein-4. We conclude that 1) both GDF-9 mRNA and protein are abundantly expressed in oocytes of primary follicles in human ovary, suggesting that the GDF-9 transcript is translated at this early stage of folliculogenesis; 2) human GDF-9B is specifically expressed in gonads at low levels; and 3) the expression of GDF-9 mRNA begins slightly earlier than that of GDF-9B in the human oocytes during follicular development. Our results are consistent with the suggestion that GDF-9 and GDF-9B may regulate human folliculogenesis in a manner specific to the ovary.

Adult↗

PubMed1999

Efficacy and safety of fluoride varnishes.

Clinical studies show that fluoride varnishes, such as Duraphat, are effective in increasing the fluoride content in the enamel and preventing caries. Varnish application is fast and easy. A professional prophylaxis before varnish application is not necessary, which decreases the application time. Patients receive significant preventive benefits with only semiannual varnish applications. Finally, and most importantly, studies show that fluoride varnishes are safe. Effectiveness, application ease, and safety give fluoride varnishes an advantage over other types of topical fluoride treatments, such as gels and rinses.

Acidulated Phosphate Fluoride↗

PubMed1998

Caries frequency in permanent teeth before and after discontinuation of water fluoridation in Kuopio, Finland.

UNLABELLED: The piped water of Kuopio, Finland, was fluoridated in 1959. Owing to strong opposition by different civic groups, water fluoridation was stopped at the end of 1992. OBJECTIVES: The aim of this study was to examine the consequences of the discontinuation on dental health. METHODS: In 1992 and 1995, independent random samples of all children aged 6, 9, 12 and 15 years were drawn from Kuopio and Jyväskylä, a nearby low fluoride town whose distribution of demographic and socio-economic characteristics was fairly similar to Kuopio's. The total number of subjects examined was 550 in 1992 and 1198 in 1995. Caries was registered clinically and radiographically by the same two calibrated dentists in both towns. RESULTS: In 1992, the mean DMFS values were lower in the fluoridated town for the two older age groups, the percentage differences for 12- and 15-year-olds being 37% and 29%, respectively. For the two younger age groups no meaningful differences could be found. In 1995, the only difference with possible clinical significance was found in the 15-year-olds in favor of the fluoridated town (18%). In 1995, a decline in caries was seen in the two older age groups in the nonfluoridated town. In spite of discontinued water fluoridation, no indication of an increasing trend of caries could be found in Kuopio. The mean numbers of fluoride varnish and sealant applications decreased sharply in both towns between 1992 and 1995. In spite of that caries declined. CONCLUSIONS: These findings suggest that the decline of caries has little to do with professional preventive measures performed in dental clinics.

Adolescent↗

PubMed1998

Accumulation of strontium and fluoride in approximal dental plaque and changes in plaque microflora after rinsing with chlorhexidine-fluoride-strontium solution.

OBJECTIVES: To find out if strontium is incorporated into plaque and enamel in vivo during a 2-week rinsing period with a chlorhexidine-fluoride-strontium solution and to determine the effects of the rinsing on the numbers of mutans streptococci and lactobacilli in plaque. SUBJECTS AND METHODS: A total of 18 adult participants rinsed their mouths twice a day for 2 weeks, first with a placebo solution and subsequently, separated by a 1-week interval without rinsing, with a chlorhexidine gluconate (0.05%)-sodium fluoride (0.04%)-strontium (100 ppm as SrCl2) rinsing solution (CXFSr) for another 2 weeks. RESULTS: After the CXFSr rinsing period the strontium and fluoride contents (microgram g-1 plaque dry weight; mean +/- sr) of approximal plaque were 32.5 +/- 4.7 and 72.8 +/- 9.0, compared with the respective contents of 8.4 +/- 1.2 and 42.0 +/- 4.8 after placebo rinsing (P = 0.0001 for both comparisons). The strontium content remained elevated for 6 weeks. The median proportion of mutans streptococci of approximal plaque of the total viable count of bacteria was 1% after placebo rinsing but decreased to 0.2% after CXFSr rinsing. The proportion of mutans streptococci remained low at 3 weeks (P = 0.018 vs placebo) but had reached the placebo level at 6 weeks. Rinsing with CXFSr solution did not reduce lactobacilli in plaque. The strontium or fluoride contents of the enamel surfaces subjected to tooth brushing did not significantly change. CONCLUSIONS: Strontium and fluoride accumulated in dental plaque during a 2-week CXFSr rinsing period and the proportion of mutans streptococci in approximal plaque was reduced at least for 3 weeks after completion of the rinsing.

Adult↗

PubMed1997

Salivary fluoride concentration in adults after different fluoride procedures.

Today, several alternatives for fluoride therapy are available. To give advice on the choice of method, the dentist should have information on how effective different fluoride treatments are in increasing salivary fluoride concentration. The aim of the present study was to measure the fluoride concentration of saliva after the use of four different fluoride methods commonly used in the Nordic countries: F mouthrinse (0.023% F), F toothpaste (1.1% F). F lozenge (0.25 mg F), and F chewing gum (0.25 mg F). In addition, a new method using toothpaste water mixture as a mouthrinse was included in the study. Fourteen adult volunteers used each of the five methods on separate days. Unstimulated saliva samples were collected at base line and 0, 10, 20, 30, 45, and 60 min after the fluoride procedure. Fluoride was separated by the microdiffusion method and analyzed using a fluoride-specific electrode. Fluoride mouthrinse and fluoride toothpaste increased the fluoride concentration of saliva significantly more than fluoride lozenge and fluoride chewing gum. For both of the latter, salivary fluoride concentration was still increased after 1 h. Toothpaste-water rinse was more effective than brushing with toothpaste. Rinsing with toothpaste-water mixture appears a good alternative for adults who need extra fluoride therapy but are not motivated enough to brush their teeth several times a day.

Administration, Oral↗

PubMed1996

Plaque fluoride and mutans streptococci in plaque and saliva before and after discontinuation of water fluoridation.

Our aim was to compare plaque fluoride and the level of mutans streptococci in saliva and plaque before and 1 and 2 years after discontinuation of water fluoridation in Kuopio, Finland. For comparison, a low-fluoride community was included in the study. Pooled plaque and saliva were collected from a random sample of 12-year-olds in both communities (n = 139). Enumeration of mutans streptococci in plaque was made on MSB agar and the level of salivary mutans streptococci was measured using the Strip mutans method. Fluoride was analyzed using a fluoride specific electrode. Caries, gingival status, fluoride varnish applications and self-reported oral health habits were recorded at baseline. Before discontinuation of fluoridation, the level of mutans streptococci in saliva was significantly lower in the fluoridated than in the non-fluoridated community. The difference in plaque mutans streptococci was not statistically significant. After discontinuation of water fluoridation, there was a significant shift towards elevated values of salivary mutans streptococci in the fluoridated community, but the level of mutans streptococci in plaque remained at the baseline level. There was no significant difference between the communities in the fluoride content of plaque either before or after discontinuation of fluoridation. From the background factors, only caries scores (higher in the non-fluoridated community) and oral hygiene (better in the non-fluoridated community) were significantly different between the communities.

Chewing Gum↗

PubMed1996

High strontium addition to chlorhexidine-fluoride gel does not increase its caries-preventive effect in rats.

One hundred Osborne-Mendel rats were weaned at the age of 21 to 22 days, inoculated with Streptococcus mutans in the mouth, and fed a semisynthetic diet for the next 43 days. The control group received no treatment. The study groups received gel applications on their molars with placebo, chlorhexidine-fluoride (CXF), CXF plus 50 ppm Sr, or CXF plus 250 ppm Sr daily for the first 21 days of the experiment Although caries was significantly reduced by CXF and CXF plus 50 ppm Sr treatments, the Sr additive did not significantly improve the caries-preventive effect of CXF. The addition of 250 ppm Sr to the CXF gel seemed markedly to weaken the effect of CXF.

Analysis of Variance↗

PubMed1995

Inhibitory effect on S. mutans by fluoride-treated conventional and resin-reinforced glass ionomer cements.

The aim of the present study was to study the effect of fluoride gel treatment on fluoride release and inhibition of acid production of Streptococcus mutans by different glass ionomer cements. Test slabs of four glass ionomer materials were fitted into the bottom of a test tube. A layer of S. mutans cells was centrifuged onto the test slabs, and the specimens were incubated for 4 h in 1.7% sucrose solution. Incubations were made using fresh, aged (29 d), aged and F-treated (1.25% F-gel), and aged, F-treated and aged samples (n = 15 per group). After each incubation, pH and F contents of the fluid phase were determined. The freshly mixed glass ionomer samples released large amounts of fluoride, and the pH fall in the fluid phase was significantly inhibited. For aged samples, the fluoride release decreased strongly and no inhibitory effect on acid production by S. mutans was seen. After application of fluoride gel, fluoride release and inhibitory effect were significantly higher than initially for all glass ionomer cements. In conclusion, all glass ionomer cements were able to take up fluoride and subsequently release it, which resulted in reestablishment of their antibacterial effect. The patterns of fluoride release and antibacterial action were virtually the same for conventional and resin-reinforced glass ionomer cements.

Amines↗

PubMed1995

Fluoride concentration, mutans streptococci and lactobacilli in plaque from old glass ionomer fillings.

Previous studies have found that the fluoride concentration of plaque growing on or adjacent to glass ionomer cement (GIC) is increased and the proportion of mutans streptococci in plaque is reduced. So far, there are only a few studies of the long-term effect of glass ionomer fillings on plaque in vivo. The aim of this study was to determine whether old GIC fillings have effects on plaque fluoride and microflora and whether this effect can be increased by topical application of fluoride on GIC fillings in vivo. The participants were 27 adults with at least 3 GIC fillings about 3 years old. Plaque was collected from sites adjacent to the GIC fillings and from the contralateral teeth, after which a 1.2% fluoride gel was applied to all teeth. Three days later, plaque was collected from the same sites as before. Stimulated saliva was also collected at both appointments. The results show that none of the patients had elevated levels of fluoride in their saliva either before or 3 days after the fluoride treatment. The fluoride concentration was 0.51 microgram/mg protein in plaque on GICs and 0.35 microgram/mg protein in plaque on contralateral teeth (p = 0.028). After the fluoride treatment, the respective fluoride concentrations were 0.59 microgram/mg and 0.75 microgram/mg (p = 0.849). No significant differences in the proportion of mutans streptococci and lactobacilli in plaque from GIC and contralateral teeth were found. The results suggest that the fluoride concentration of plaque growing on old GIC fillings is slightly increased. In this study, however, this had no significant effect on the cariogenic microflora.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Fluoride varnish versus acidulated phosphate fluoride gel: a 3-year clinical trial.

The aim of this trial was to compare the caries-preventive effect of sodium fluoride varnish and acidulated phosphate fluoride (APF) gel. A total of 254 children aged 12-13 years with high past caries experience were randomly divided into two groups. The participants received semi-annual applications of either fluoride varnish or APF gel for 3 years. During the study, the mean (+/- SD) total DMFS increments of the varnish and gel groups were 6.8 +/- 5.6 and 7.7 +/- 6.4, respectively, when initial caries was included, and 3.1 +/- 3.7 and 3.6 +/- 4.6 when initial caries was excluded. The difference was most evident on the approximal surfaces (varnish: 1.4 +/- 2.4; gel: 1.9 +/- 3.1). However, this difference was not statistically significant. Although larger studies are needed for firm conclusions about the comparative effect of the two fluoride measures, the results suggest that fluoride varnish is as effective as fluoride gel at least in preventing approximal caries. Taking into account the shorter treatment time, using fluoride varnish for professional applications seems justified.

Acidulated Phosphate Fluoride↗

PubMed1994

Comparison of glass-ionomer and resin-based fissure sealants: a 2-year clinical trial.

In recent years, the interest in the use of glass-ionomer materials as fissure sealants has increased. The aim of this study was to compare the retention and caries-preventive effect of glass-ionomer (Fuji III) and resin-based light-cured (Delton) fissure sealants. Three health center dentists applied the sealants to 166 children; glass-ionomer sealants on one side and resin-based sealants on the contralateral side of the mouth. After 2 yr, one pair of molar teeth in the mouths of 151 children was compared. Twenty-six percent of glass-ionomer and 82% of resin-based sealants were totally present (P < 0.001). During the 2 yr, in both groups 4.6% of the sealed surfaces became carious. The results show that the retention of glass-ionomer sealants is markedly inferior to the resin-based sealants. In this study, however, no difference in caries increment on the sealed surfaces was observed. This may be due to the different mechanism of caries prevention for the sealant materials, or to the overall low caries activity of the participants.

Adolescent↗

PubMed1994

Caries-preventive effect of fluoride varnish with different fluoride concentrations.

Based on the current concept of the caries-preventive mechanism of fluoride, the fluoride concentration of some professionally applied fluoride preparations appears unnecessarily high. The aim of this trial was to study whether reducing the fluoride concentration of the sodium fluoride varnish Duraphat from the present 2.3% to 1.1% affects its clinical efficacy. A total of 274 children aged 12-14 years and having high past caries experience were randomly divided into two groups. The participants received 3 annual applications of either 2.3% or 1.1% varnish for 3 years. Clinical and radiographical examinations were performed at baseline and at the end of the follow-up. The mean total DMFS increments of the 2.3% and 1.1% varnish groups were 5.5 (SD 5.7) and 5.7 (5.3), respectively, when initial caries was excluded, and 14.3 (12.0) and 14.9 (12.9) when initial caries was included. The differences were statistically non-significant. There were no significant differences in the surface-specific DMFS increments between the groups either. The 95% confidence interval for the difference between the groups in total mean DMFS increment (initial caries excluded) was calculated at -1.21 to + 1.54, i.e. at this level of confidence at most 0.5 surfaces per year would have been saved using the more concentrated varnish. Consequently, it can be stated at a reasonable level of certainty that if a difference in the efficacy of the two varnishes exists, it probably is minute. Lowering the fluoride concentration of Duraphat is worth considering at least when used for children.

Adolescent↗

PubMed1994

Relationship between oral hygiene and approximal caries in 15-year-old Norwegians.

The objective of the present study was to investigate the relationship between oral hygiene level, as judged from the number of non-bleeding papillae (NBP), and approximal caries development and progression in 14- to 15-year-old Norwegians. NBP, according to Gjermo, were registered in 165 15-year-old Norwegians. Approximal lesions in the outer half (D1) or in the inner half (D2) of the enamel or in dentin (D3) and the total numbers of carious approximal surfaces (D1 + D2 + D3), filled approximal surfaces, and sound approximal surfaces were recorded from bite-wing radiographs from premolars and molars at the age of 14 and 15 years (values expressed as mean +/- SD). The average number of NBP in the whole group was 4.6 +/- 4.5. One group with good oral hygiene (NBP > or = 5, 8.7 +/- 3.3, n = 76) and one group with bad oral hygiene (NBP < 5, 1.2 +/- 1.5, n = 89) were established. Carious approximal surfaces and filled approximal surfaces were significantly higher in the group with few than in the group with many NBP (6.0 +/- 5.9 vs. 1.7 +/- 2.8 and 2.6 +/- 4.3 vs. 0.9 +/- 1.8, respectively). The number of lesions at the age of 15 and progression of lesions from 14 to 15 years were also significantly higher in the group with few NBP. It is concluded than in populations exposed regularly to fluoride, the oral hygiene level may be an important indicator of a high caries risk.

Adolescent↗

PubMed1994

Fluoride release and effect on enamel softening by fluoride-treated and fluoride-untreated glass ionomer specimens.

The effect of fluoride application on fluoride release and enamel protection was studied using conventional and light-activated glass ionomers and composite. The specimens prepared from the materials were tested as (1) freshly mixed, (2) aged (29 days), (3) aged and fluoride treated, and (4) aged, fluoride treated, and aged (29 days). For fluoride application, the specimens were immersed in 1.2% NaF solution for 10 min and washed. After handling, the specimens were glued on polished bovine enamel slabs and immersed in lactic acid (pH 5.0) for 3 h. The microhardness of the enamel was measured before and after the acid immersion. Freshly mixed glass ionomers significantly prevented enamel softening. The effect disappeared (conventional glass ionomer) or decreased (light-activated glass ionomer) during aging, but was reestablished by fluoride application. After the subsequent 4 weeks of aging, no significant protective effect could be seen for either of the glass ionomers. The fluoride release, which was greatly increased by fluoride application, was still elevated after 4 weeks of aging for both materials.

Animals↗