Ella A. Naumova

Dynamic changes in saliva after acute mental stress.

Stress-related variations of fluoride concentration in supernatant saliva and salivary sediment, salivary cortisol, total protein and pH after acute mental stress were assessed. The hypothesis was that stress reactions have no influence on these parameters. Thirty-four male students were distributed into two groups: first received the stress exposure followed by the same protocol two weeks later but without stress exposure, second underwent the protocol without stress exposure followed by the stress exposure two weeks later. The stressor was a public speech followed by tooth brushing. Saliva was collected before, immediately after stress induction and immediately, at 10, 30 and 120 min. after tooth brushing. Cortisol concentrations, total protein, intraoral pH, and fluoride content in saliva were measured. The data were analyzed statistically. Salivary sediment was ca 4.33% by weight of whole unstimulated saliva. Fluoride bioavailability was higher in salivary sediment than in supernatant saliva. The weight and fluoride concentration was not altered during 2 hours after stress exposure. After a public speech, the salivary cortisol concentration significantly increased after 20 minutes compared to the baseline. The salivary protein concentration and pH also increased. Public speaking influences protein concentration and salivary pH but does not alter the fluoride concentration of saliva.

The oral mucosal surface and blood vessels

IntroductionDetailed information about the size of the oral mucosa is scarce in the literature, and those studies that do exist do not take into account the size of the tongue or the enlargement of the surface by the papillae. Because of the various functions of the oral mucosa in the maintenance of oral health, knowledge of its true size may provide a better understanding of the physiology of the oral cavity and some oral diseases and direct future therapeutic strategies. The aim of this study was to determine the total size of the oral mucosa.MethodsFive human adult cadaver heads were cut in the median sagittal plane, and the total area of the oral surface was determined using silicon casts. The surface of the tongue was measured with quantitative profilometry. Photographs of oral blood vessels were taken in different areas of the oral mucosa of adult test subjects using intravital microscopy, and the pictures were compared with vessel casts of the oral mucosal capillaries of a maccaca fasciculrais monkey, which was studied using a scanning electron microscope.ResultsThe results showed that the dorsal side of the tongue comprises a large proportion of the total oral mucosal surface. The surface area of the epithelium increases moving from anterior to posterior on the tongue, and the number of underlying blood vessels increases proportionally.ConclusionsIt can be concluded that the back of the tongue plays an important role in the oral resorption of drugs. Clinical relevance: The results may be of relevance for the delivery and development of oral drug application.

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.

Influence of individual saliva secretion on fluoride bioavailability.

The aim of this preliminary investigation was to compare the individual saliva secretion rate with the fluoride bioavailability in saliva after using sodium fluoride and amine fluoride. Methods: To assess oral fluoride kinetics 10 highly trained volunteers brushed their teeth with one of the formulations and saliva was collected. The amount of saliva was measured, and the fluoride content was determined. Data underwent statistical analysis using the Mann-Whitney-U test and Pearson correlation. The ex vivo experiment I included individual saliva collection of the same volunteers. Then the oral hygiene products were solved in equal amounts of whole saliva (ex-vivo experiment II), and the fluoride content was measured. Finally, both products were dispersed in distilled water (ex-vivo experiment III) to calculate the dissociation of both products in water. Results: In vivo results of fluoride content after 3 min. tooth brushing demonstrated a negative correlation with saliva secretion: for NaF r = -0.695 (p<0.01) and for amine fluoride r = -0.446 (p<0.01). The in-vitro experiment I resulted for NaF in 251.7±22.4 µg/g fluoride and for amine fluoride in 171.7±14.4 µg/g. Conclusions: Fluoride bioavailability of saliva after exposure to NaF was higher compared to amine fluoride. The individual secretion rate changes the fluoride content and normal secretors keep the fluoride availability longer.

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®.

Dynamics of Fluoride Bioavailability in the Biofilms of Different Oral Surfaces after Amine Fluoride and Sodium Fluoride Application

It was the aim of this study to investigate differences in fluoride bioavailability in different oral areas after the application of amine fluoride (AmF) and sodium fluoride (NaF). The null hypothesis suggested no differences in the fluoride bioavailability. The tongue coating was removed and biofilm samples from the palate, oral floor and cheeks were collected. All subjects brushed their teeth with toothpaste containing AmF or NaF. Specimens were collected before, as well as immediately after and at 30 and 120 minutes after tooth brushing. The fluoride concentration was determined. The area under the curve was calculated for each location and compared statistically. In the tongue coating, fluoride concentration increased faster after NaF application than after AmF application. After 30 minutes, the fluoride concentration decreased and remained stable until 120 minutes after AmF application and returned to baseline after NaF application. The difference between the baseline and the endpoint measurements was statistically significant. The fluoride concentration in the tongue coating remained at a higher level compared with the baseline for up to 120 minutes post-brushing. This may indicate that the tongue coating is a major reservoir for fluoride bioavailability. The results also indicate an unequal fluoride distribution in the oral cavity.

Effects of Fluoridated Milk on Root Dentin Remineralization

Background The prevalence of root caries is increasing with greater life expectancy and number of retained teeth. Therefore, new preventive strategies should be developed to reduce the prevalence of root caries. The aim of this study was to investigate the effects of fluoridated milk on the remineralization of root dentin and to compare these effects to those of sodium fluoride (NaF) application without milk. Methods Thirty extracted human molars were divided into 6 groups, and the root cementum was removed from each tooth. The dentin surface was demineralized and then incubated with one of the following six solutions: Sodium chloride NaCl, artificial saliva, milk, milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Serial sections were cut through the lesions and investigated with polarized light microscopy and quantitative morphometry, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The data were statistically evaluated using a one-way ANOVA for multiple comparisons. Results The depth of the lesion decreased with increasing fluoride concentration and was the smallest after incubation with artificial saliva+10 ppm fluoride. SEM analysis revealed a clearly demarcated superficial remineralized zone after incubation with milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Ca content in this zone increased with increasing fluoride content and was highest after artificial saliva+10 ppm fluoride incubation. In the artificial saliva+10 ppm fluoride group, an additional crystalline layer was present on top of the lesion that contained elevated levels of F and Ca. Conclusion Incubation of root dentin with fluoridated milk showed a clear effect on root dentin remineralization, and incubation with NaF dissolved in artificial saliva demonstrated a stronger effect.

Fluoride bioavailability in saliva during acute psychological stress

The aim of this study was to investigate the influence of acute stress on salivary fluoride bioavailability. Acute psychological stress was induced using a standardized model of public speaking. The saliva of male subjects was collected before and after the public speaking task and immediately, 10, 30, and 120 minutes after tooth brushing according to the Bass method with a dentifrice containing amine fluoride (AmF) or oral hygiene tablets containing sodium fluoride (NaF). Subjective psychological responses to public speaking were evaluated using the State-Trait Anxiety Inventory (STAI). Saliva cortisol levels were analyzed as an objective stress marker. The saliva secretion rate was measured both before and after public speaking. Saliva fluoride content was measured. Group comparisons were calculated using a univariate analysis of variance (ANOVA). In all analyses, the alpha-level was set at 0.05. Public speaking significantly increased state anxiety (p<0.001) and salivary cortisol concentrations (p<0.001). Acute stress did not influence salivary secretion rates. In the AmF group, stressed individuals exhibited statistically significant (p=0.044) lower fluoride concentration in saliva compared with the nonstressed subjects Acute psychological stress reactions do not cause hyposalivation but decrease fluoride bioavailability after using a dentifrice containing AmF. Fluoride bioavailability during acute stress is dependent on fluoride formulation.

Comparative Qualitative and Quantitative Assessment of Biomineralization of Tooth Development in Man and Zebrafish (Danio rerio)

It was the aim of this study to investigate the distribution of Ca, P, and C in predentin, mineralizing dentin, and mature dentin of human tooth buds and compare these results with those of zebrafish (Danio rerio) teeth using energy dispersive X‐ray analysis (EDX) element analysis. The mandible of a 16‐week‐old human fetus containing 6 mineralizing tooth buds and three complete heads of zebrafish were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80‐μm thickness were cut in frontal‐dorsal direction, and from these sections, polarized light micrographs were taken. The sections with tooth buds were then investigated with scanning electron microscopy, and EDX element analysis was performed with a Philips XL 30 FEG scanning microscope and an EDAX energy‐dispersive X‐ray system using spot measurements, EDX line‐scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, and mature dentin. The Ca and P content increased rapidly from outer predentin toward mineralizing dentin in human tooth buds and in zebrafish teeth. The Ca/P ratio was different for predentin and dentin areas, reflecting different calcium phosphate compositions in predentin and fully mineralized dentin. Because of the similarities between human tooth buds and zebrafish teeth, it can be concluded that the zebrafish tooth development may be an excellent model for studying biomineralization processes during odontogenesis. Anat Rec, 291:571–576, 2008.

Morphological analysis and three-dimensional reconstruction of the SMAS surrounding the nasolabial fold

BACKGROUND The superficial musculoaponeurotic system (SMAS), a structure that has been discussed with some controversy, has a complex morphological architecture. MATERIAL AND METHODS Histological analysis was performed on tissue blocks of the nasolabial fold (NLF) collected postmortem from formalin-fixed bodies of one male and one female donor. Serial histological sections were made, stained and digitized. Three-dimensional reconstructions of the histological structures were performed. Specimen- and location-specific differences were determined. SEM analysis of the NLF tissue block was performed. RESULTS The NLF SMAS is a fibro-muscular, three-dimensional meshwork bolstered with fat cells. Two SMAS structure types were identified adjacent to the NLF. The cheek SMAS structure showed a regular, vertical and parallel alignment of the fibrous septa, building a three-dimensional meshwork of intercommunicating compartments. It changed its morphology, condensing while transiting the NLF and passing over to form an irregular structure in the upper lip region. SEM analysis demonstrated the connection between the fibrous meshwork and the fat cells. SMAS blood circulation expanded subcutaneously without perforating the fibro-muscular septa. CONCLUSIONS The NLF has a recognizable condensed cheek SMAS structure and represents the transition zone between the two SMAS types. Specimen-specific morphological differences necessitate individual planning and area-specific surgical procedures.