Peter Gaengler

Effect of fluoride toothpastes on enamel demineralization

BackgroundIt was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization.MethodsA 3 × 3 mm window on the enamel surface of 90 human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 6 groups and the lower half of the window was covered with varnish serving as control. The teeth were immersed in a toothpaste slurry containing: placebo tooth paste (group 1); remineralization solution (group 2); Elmex Anticaries (group 3); Elmex Sensitive (group 4); Blend-a-med Complete (group 5) and Colgate GRF (group 6). Ten teeth of each group were used for the determination of the F- content in the superficial enamel layer and acid solubility of enamel expressed in soluble phosphorus. Of 6 teeth of each group serial sections were cut and investigated with polarization light microscopy (PLM) and quantitative energy dispersive X-ray analysis (EDX).ResultsThe PLM results showed an increased remineralization of the lesion body in the Elmex Anticaries, Elmex Sensitive and Colgate GRF group but not in the Blend-a-med group. A statistically significant higher Ca content was found in the Elmex Anticaries group. The fluoride content in the superficial enamel layer was significantly increased in both Elmex groups and the Blend-a-med group. Phosphorus solubility was significantly decreased in both Elmex groups and the Blend-a-med group.ConclusionIt can be concluded that amine fluoride compounds in toothpastes result in a clearly marked remineralization of caries like enamel lesions followed by sodium fluoride and sodium monofluorophosphate formulations.

Chlorhexidine-loaded calcium phosphate nanoparticles for dental maintenance treatment: combination of mineralising and antibacterial effects

One of the main problems in dental medicine is the growth of bacterial biofilms on tooth surfaces which cause caries and periodontitis. We have developed a new system for oral hygiene and dental treatment that consists of either a paste or a rinsing solution containing calcium phosphate nanoparticles, functionalized with the antibacterial agent chlorhexidine. As calcium phosphate is the natural component of tooth mineral, it can lead to the remineralization of damaged enamel, while chlorhexidine prevents the colonization of the tooth surface by bacteria. In the form of a paste, a bifunctional system with both mineralizing and antibacterial properties is obtained. The nanoparticles may also stick to open dentin tubules at the root surface due to their coating with carboxymethyl cellulose. In vitro studies on teeth show that the paste sticks well to the root surface and closes dentin tubules.

Calcium transport in human salivary glands: a proposed model of calcium secretion into saliva

Salivary calcium plays a vital role in bio-mineralization of dental enamel and exposed dentin. In order to elucidate the yet unknown cellular and molecular mechanisms of calcium secretion in human salivary glands the presence of various relevant plasma membrane transport systems for calcium were investigated. Using an RT-PCR approach, expression of the epithelial calcium channel (CaT-Like), the calcium binding protein (calbindin-2), the endoplasmic reticulum pumps (SERCA-2 and -3), and the plasma membrane calcium ATPases (PMCA-1, -2, and -4), were found in parotid and submandibular glands. Immunohistochemistry revealed that CaT-Like is located in the basolateral plasma membrane of acinar cells; while calbindin-2, SERCA-2 and SERCA-3 were found inside the acinar cells; and PMCA-2 was found in the apical membrane and in the secretory canaliculi between the cells. Based on these findings, we propose the following model of calcium secretion in human salivary glands: (1) calcium enters the acinar cell at the basolateral side via calcium channel CaT-Like (calcium influx); (2) intracellular calcium is taken up into the endoplasmic reticulum by SERCA-2 and possibly SERCA3 or bound to calbindin-2 (intracellular calcium pool); and (3) calcium is secreted by PMCAs at the apical plasma membrane (calcium efflux).

Effect of pH of amine fluoride containing toothpastes on enamel remineralization in vitro.

BackgroundOne of the important factors of the demineralization and remineralization equilibrium of enamel is the pH of the surrounding solutions. Effort has been laid in the formulation of different fluoride compounds and the fluoride content in toothpastes but much less is known about the influence of the pH of the toothpastes on their effectiveness. It was therefore the aim of this study to investigate the influence of different pH levels on enamel remineralization in an in vitro experiment using polarization light microscopy and EDX quantitative element analysis.MethodsA 5 × 5 mm window on the enamel surface of 40 caries free extracted human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 8 groups and the lower half of the window was covered with varnish serving as control. Each group was then immersed in toothpaste slurry containing amine fluoride (1400 ppm) at pH 4.1, 4.5, 5.1 and 6.9 or control toothpaste slurry without fluoride at pH 4.3, 4.7, 5.3 and 7.0. Serial sections were cut through the lesions and investigated with polarization light microscopy and quantitative EDX element analysis.ResultsThe PLM results showed a decreased porous volume of the body of the lesion after incubation with fluoridated toothpaste at pH 4.53 and 5.16. No differences between the experimental window and the control window were found in the other groups. The quantitative element analysis showed no differences in the element content of any of the groups.ConclusionFrom the results it can be concluded that slightly acidified fluoridated dentifrices may have a certain positive effect on enamel remineralization.

Fluoride bioavailability in saliva and plaque

BackgroundDifferent fluoride formulations may have different effects on caries prevention. It was the aim of this clinical study to assess the fluoride content, provided by NaF compared to amine fluoride, in saliva and plaque.MethodsEight trained volunteers brushed their teeth in the morning for 3 minutes with either NaF or amine fluoride, and saliva and 3-day-plaque-regrowth was collected at 5 time intervals during 6 hours after tooth brushing. The amount of collected saliva and plaque was measured, and the fluoride content was analysed using a fluoride sensitive electrode. All subjects repeated all study cycles 5 times, and 3 cycles per subject underwent statistical analysis using the Wilcoxon-Mann-Whitney test.ResultsImmediately after brushing the fluoride concentration in saliva increased rapidly and dropped to the baseline level after 360 minutes. No difference was found between NaF and amine fluoride. All plaque fluoride levels were elevated after 30 minutes until 120 minutes after tooth brushing, and decreasing after 360 minutes to baseline. According to the highly individual profile of fluoride in saliva and plaque, both levels of bioavailability correlated for the first 30 minutes, and the fluoride content of saliva and plaque was back to baseline after 6 hours.ConclusionsFluoride levels in saliva and plaque are interindividually highly variable. However, no significant difference in bioavailability between NaF and amine fluoride, in saliva, or in plaque was found.

Fluoride bioavailability in saliva using DENTTABS® compared to dentifrice

It was the aim of this study to assess fluoride retained in saliva after use of fluoride-containing tablet DENTTABS® compared to toothpaste containing amine fluoride. Four subjects (2 normal saliva secretors, 1 slow secretor, and 1 fast secretor) participated in this crossover study comparing DENTTABS® and ELMEX®. After baseline sample collection, calibrated study personnel brushed the subjects’ teeth with the assigned product for 3 minutes. Saliva samples were taken at baseline (T0), immediately after brushing (T1) and then 10 (T2), 25 (T3) and 85 (T4) minutes post-brushing. The amount of saliva collected was measured, and the fluoride content was analysed. All 4 subjects repeated all study cycles 5 times. Statistical analysis was done using the Mann-Whitney-U test and Spearman correlation. The fluoride retention was significantly higher after brushing with DENTTABS® at T1 and T2. There was a correlation between individual salivary flow rate and the F- content. Flow rate in g/min ranged from 1.1 to 3.8 at T1 and from 0.2 to 1.1 at T4 with much higher F- retention in slow secreting cycles. The saliva fluoride clearance kinetics of two equal amounts of fluoride-containing oral hygiene products demonstrate higher retention for DENTTABS®.

Kinetics of fluoride bioavailability in supernatant saliva and salivary sediment

UNLABELLEDnThe assessment of the fluoride kinetics in whole saliva as well as in the different salivary phases (supernatant saliva and sediment) is essential for the understanding of fluoride bioavailability.nnnOBJECTIVESnTo assess the fluoride content, provided by sodium fluoride and amine fluoride, in the supernatant saliva and in salivary sediment.nnnMETHODSnSeven trained volunteers were randomly attributed to 2 groups in a cross-over design and brushed their teeth in the morning for 3 min with a product containing either sodium fluoride or amine fluoride. Saliva was collected before, immediately after tooth brushing and 30, 120, and 360 min later and measured. The samples were centrifuged 10 min at 3024 × g. Fluoride content of the supernatant saliva and of the sediment was analysed using a fluoride sensitive electrode. All subjects repeated the study cycles 2 times, and statistical analyses were made using the nonparametric sign test for related samples, the Wilcoxon-Mann-Whitney-test for independent samples.nnnRESULTSnThere was a significant increase in fluoride immediately after tooth brushing in both groups in saliva and sediment. The distribution of fluoride between salivary sediment and supernatant saliva (ratio) varied considerably at the different collection times: decreased from 17.87 in baseline samples of saliva to 0.07 immediately and to 0.86 half an hour after tooth brushing in the sodium fluoride group and from 14.33 to 2.85 and to 3.09 in the amine fluoride group. Furthermore after 120 min and after 360 min after tooth brushing the ratio increased from 17.6 to 31.6 in the sodium fluoride group and from 20.5 to 25.76 in the amine fluoride group. No difference was found in the sediment-supernatant saliva ratio between the sodium fluoride and the amine fluoride groups 360 min after tooth brushing.nnnCONCLUSIONnFor the assessment of fluoride kinetics in whole saliva it is necessary to pay attention to at least four factors: fluoride formulation, time after fluoride application, fluoride concentration in supernatant saliva and fluoride concentration in salivary sediment. This study was approved by the Ethical Committee of the University of Witten/Herdecke permission 21/2008.

Performance of Atraumatic Restorative Treatment (ART) depending on operator-experience

OBJECTIVESnOral health care is not of major interest in developing countries because of lack of infrastructure and professional manpower. Therefore, atraumatic restorative treatment (ART) was introduced by the World Health Organization to be performed by dental auxiliary personnel. The aim of this study was to evaluate the performance of ART depending on operator-experience in The Republic of The Gambia.nnnMETHODSnOne hundred twenty-eight newly inserted restorations were followed up for 12 months using the clinical ART index in a prospective and blinded study design. The patients were randomly assigned to operators. The clinical performance was compared among three groups: trainees, experienced Community Oral Health Workers (COHW), and professional dentists. The difference in success rates was calculated at a 95 percent confidence interval.nnnRESULTSnThere was a statistically significant difference between trainees and dentists in performing leakage/gap-free one-surface restorations (P < 0.05). No significant differences were found between the two groups of auxiliaries (trainees versus experienced COHWs, P > 0.05). Finally, both groups--experienced COHWs and dentists--performed restorations not showing statistically significant differences (P > 0.05).nnnCONCLUSIONSnFor The Republic of The Gambia--especially for areas with underdeveloped medical infrastructure--training and assignment to perform ART can be recommended for auxiliary dental staff of Community Oral Health Workers.

Longitudinal micromorphological 15-year results of posterior composite restorations using three-dimensional scanning electron microscopy.

OBJECTIVESnHybrid composite restorations in posterior teeth were evaluated over 15 years using the semiquantitative Clinical, Photographic and Micromorphologic (CPM) index. It was a further aim to quantitate the surface morphology by three-dimensional scanning electron microscopy (3D-SEM).nnnMETHODSnThirty seven hybrid composite restorations (Ketac-Bond/Visio-Molar X, ESPE, Seefeld/Germany) were longitudinally followed up. Parallel to clinical assessment replicas were taken at baseline, after 1, 5, 10 and 15 years and evaluated by SEM, and profilometrical analyses of 3D-SEM data were computed. The profilometrical results were statistically analysed by ANOVA. The level of significance was set to p<0.05.nnnRESULTSnThe semiquantitative micromorphological evaluation exhibited the most considerable deterioration within the first year and up to 5 years of function. Less change was detected during the next 10 years. The profilometrical quantification showed raising depth of the negative marginal ledges with a mean of 27.2μm (range 0.6-94.5μm) after 10 years, with no statistically significant changes from 5 to 10 and 10 to 15 years. The 3D-SEM revealed marginal grooves beneath the level of the ledges (mean 34.5μm after 5 years) within the bonding zone, exposing enamel margins. Leakages, marginal fractures and surface roughness did not seriously deteriorate the quality of restorations.nnnCONCLUSIONSnHybrid composite restorations of Class I and II cavities surviving the first five years performed well over 15 years of function. Quantitative 3D-SEM profilometrical measurements revealed the dynamics of marginal behaviour over time.nnnCLINICAL SIGNIFICANCEnLong-term parallel clinical and micromorphological evaluation of posterior composite restorations of Class I and Class II cavities documented the clinical safety and acceptable longevity. The longitudinal 3D micromorphologic assessment of the surface changes and of the marginal behaviour revealed deteriorating as well as improving factors hidden in clinical performance.

Dental lessons from past to present: ultrastructure and composition of teeth from plesiosaurs, dinosaurs, extinct and recent sharks

Teeth represent the hardest tissue in vertebrates and appear very early in their evolution as an ancestral character of the Eugnathostomata (true jawed vertebrates). In recent vertebrates, two strategies to form and mineralize the outermost functional layer have persisted. In cartilaginous fish, the enameloid is of ectomesenchymal origin with fluoroapatite as the mineral phase. All other groups form enamel of ectodermal origin using hydroxyapatite as the mineral phase. The high abundance of teeth in the fossil record is ideal to compare structure and composition of teeth from extinct groups with those of their recent successors to elucidate possible evolutionary changes. Here, we studied the chemical composition and the microstructure of the teeth of six extinct shark species, two species of extinct marine reptiles and two dinosaur species using high-resolution chemical and microscopic methods. Although many of the ultrastructural features of fossilized teeth are similar to recent ones (especially for sharks where the ultrastructure basically did not change over millions of years), we found surprising differences in chemical composition. The tooth mineral of all extinct sharks was fluoroapatite in both dentin and enameloid, in sharp contrast to recent sharks where fluoroapatite is only found in enameloid. Unlike extinct sharks, recent sharks use hydroxyapatite as mineral in dentin. Most notably and hitherto unknown, all dinosaur and extinct marine reptile teeth contained fluoroapatite as mineral in dentin and enamel. Our results indicate a drastic change in the tooth mineralization strategy especially for terrestrial vertebrates that must have set in after the cretaceous period. Possibly, this is related to hitherto unconsidered environmental changes that caused unfavourable conditions for the use of fluoroapatite as tooth mineral.