Impact of manual toothbrush design on plaque removal efficacy.

BACKGROUND: Effective dental plaque removal is essential for oral health. Different toothbrush parameters including head-size, filament-diameter and interdent-height and different brushing movements like horizontal, rotating and vertical may affect plaque removal efficacy. The purpose of the study was to examine plaque removal efficacy of different design parameters of manual toothbrushes. METHODS: Eight manual toothbrushes were tested using a validated robot test to examine efficacy of toothbrush on replicated human teeth. Characteristics tested were: (i) head-size, (ii) filament-diameter, (iii) cutting-height, (iv) hardness, (v) interdental-height. Each test ran five times in horizontal, rotating, vertical movements. Simulated Plaque removal was evaluated using automated plaque planimetry: 30 fields/tooth, 13 areas representing buccal, lingual, proximal tooth sites. The Kolmogorov-Smirnov-test was applied to test tooth surface variables for normal distribution of plaque removal values. Parameters were analysed by independent two-sample t-test to assess mean differences. Where null hypothesis of normality was rejected, the Wilcoxon-Mann-Whitney-U-test was used. RESULTS: Plaque removal was significantly better with toothbrush having smaller head-size (compact vs. full-size); smaller filament-diameter (0.12 mm vs. 0.15 mm); larger cutting-height (12 mm vs. 9 mm); softer filaments (0.15 or 0.18 mm vs. 0.23 mm) and greater interdent-height difference (8.5/11 mm vs. 10/11 mm). CONCLUSIONS: Manual brushes allowing filaments free to flex with longer, softer and/or having a difference in filament length overall removed significantly more simulated plaque as compared to more standard flat trim, stiff brushes with shorter, harder bristles and a larger head size. While limited by the in vitro nature of the study design, this indicates that the advances in toothbrush design can further enhance plaque removal.

Robot and mechanical testing of a specialist manual toothbrush for cleaning efficacy and improved force control.

BACKGROUND: Toothbrushes require flexibility to access all dental surfaces and remove plaque effectively, but they should also aim to prevent or limit overbrushing and consequent damage to teeth and gums. In two studies, the physical properties and cleaning performance of specialist test toothbrushes with flexible necks were compared to a reference rigid-necked toothbrush. METHODS: In Study 1, a universal testing machine (Instron E 10,000) with a specially designed setup was used to test the deflection behaviour of toothbrush head and neck. Untufted toothbrushes were fixed in a custom holder and force was applied to the head while the deflection was measured. In Study 2, one control and five test toothbrushes were assessed using a robot system to simulate the cleaning of artificial plaque from defined surfaces of artificial replicated human teeth in a model oral cavity (typodonts). RESULTS: Study 1 showed that the flexible-neck toothbrush deflected 2 to 2.5 times more than the rigid-neck reference toothbrush when same force was applied to the toothbrush head. Study 2 revealed that all five test toothbrushes showed statistically superior simulated plaque removal to the reference toothbrush. This superiority was observed for all test toothbrushes employing horizontal and rotating brushing action (all p = 0.001) but only three of the five toothbrushes when vertical brushing was employed (all p = 0.001). Cleaning efficacy of the test toothbrushes was demonstrated both interdentally and at the gumline locations. The Complete Protection toothbrush showed the most effective cleaning performance followed by the Repair and Protect and Rapid Relief toothbrushes. CONCLUSION: The addition of a flexible-neck component to the toothbrush designs helped to reduce stiffness and may allow more effective cleaning compared to rigid designs with controlled force distribution on the teeth and gums. This may help to provide plaque control at all potential risk areas in an in vitro robot model and could support good oral hygiene in-use.

Regeneration and Repair in Endodontics-A Special Issue of the Regenerative Endodontics-A New Era in Clinical Endodontics.

Caries is the most common cause of pulp-periapical disease. When the pulp tissue involved in caries becomes irreversibly inflamed and progresses to necrosis, the treatment option is root canal therapy because the infected or non-infected necrotic pulp tissue in the root canal system is not accessible to the host's innate and adaptive immune defense mechanisms and antimicrobial agents. Therefore, the infected or non-infected necrotic pulp tissue must be removed from the canal space by pulpectomy. As our knowledge in pulp biology advances, the concept of treatment of pulpal and periapical disease also changes. Endodontists have been looking for biologically based treatment procedures, which could promote regeneration or repair of the dentin-pulp complex destroyed by infection or trauma for several decades. After a long, extensive search in in vitro laboratory and in vivo preclinical animal experiments, the dental stem cells capable of regenerating the dentin-pulp complex were discovered. Consequently, the biological concept of 'regenerative endodontics' emerged and has highlighted the paradigm shift in the treatment of immature permanent teeth with necrotic pulps in clinical endodontics. Regenerative endodontics is defined as biologically based procedures designed to physiologically replace damaged tooth structures, including dentin and root structures, as well as the pulp-dentin complex. According to the American Association of Endodontists' Clinical Considerations for a Regenerative Procedure, the primary goal of the regenerative procedure is the elimination of clinical symptoms and the resolution of apical periodontitis. Thickening of canal walls and continued root maturation is the secondary goal. Therefore, the primary goal of regenerative endodontics and traditional non-surgical root canal therapy is the same. The difference between non-surgical root canal therapy and regenerative endodontic therapy is that the disinfected root canals in the former therapy are filled with biocompatible foreign materials and the root canals in the latter therapy are filled with the host's own vital tissue. The purpose of this article is to review the potential of using regenerative endodontic therapy for human immature and mature permanent teeth with necrotic pulps and/or apical periodontitis, teeth with persistent apical periodontitis after root canal therapy, traumatized teeth with external inflammatory root resorption, and avulsed teeth in terms of elimination of clinical symptoms and resolution of apical periodontitis.

Clinical validation of robot simulation of toothbrushing--comparative plaque removal efficacy.

BACKGROUND: Clinical validation of laboratory toothbrushing tests has important advantages. It was, therefore, the aim to demonstrate correlation of tooth cleaning efficiency of a new robot brushing simulation technique with clinical plaque removal. METHODS: Clinical programme: 27 subjects received dental cleaning prior to 3-day-plaque-regrowth-interval. Plaque was stained, photographically documented and scored using planimetrical index. Subjects brushed teeth 33-47 with three techniques (horizontal, rotating, vertical), each for 20s buccally and for 20s orally in 3 consecutive intervals. The force was calibrated, the brushing technique was video supported. Two different brushes were randomly assigned to the subject. Robot programme: Clinical brushing programmes were transfered to a 6-axis-robot. Artificial teeth 33-47 were covered with plaque-simulating substrate. All brushing techniques were repeated 7 times, results were scored according to clinical planimetry. All data underwent statistical analysis by t-test, U-test and multivariate analysis. RESULTS: The individual clinical cleaning patterns are well reproduced by the robot programmes. Differences in plaque removal are statistically significant for the two brushes, reproduced in clinical and robot data. Multivariate analysis confirms the higher cleaning efficiency for anterior teeth and for the buccal sites. CONCLUSIONS: The robot tooth brushing simulation programme showed good correlation with clinically standardized tooth brushing.This new robot brushing simulation programme can be used for rapid, reproducible laboratory testing of tooth cleaning.

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

OBJECTIVES: Hybrid 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). METHODS: Thirty 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. RESULTS: The 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. CONCLUSIONS: Hybrid 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. CLINICAL SIGNIFICANCE: Long-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.

Fluoride bioavailability in saliva and plaque.

BACKGROUND: Different 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. METHODS: Eight 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. RESULTS: Immediately 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. CONCLUSIONS: Fluoride 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.

Total and free fluoride concentrations of African dentifrices marketed in West Africa.

OBJECTIVE: To determine the fluoride concentrations of commercial dentifrices marketed in West Africa. DESIGN: In vitro measurement of the total fluoride concentration by liquid gas chromatography, and of the free fluoride concentration with a fluoride sensitive electrode. SETTING: Collection of fluoride dentifrices in public markets and supermarkets in and around the capital of The Republic of The Gambia, Banjul, after a systematic search. MATERIALS: All commercially available different brands sold in The Gambia and produced locally or in other African countries (Egypt, Morocco, Nigeria and South Africa). OUTCOME MEASURES: Total and free fluoride concentrations of dentifrices in parts per million. RESULTS: Seven different dentifrices were detected with NaMFP as the predominant fluoride source. Four dentifrices showed a total fluoride concentration above 1,000 ppm F-. The products showed - in general - a lower free fluoride concentration. Only one product with NaF as fluoride supplement showed both total and free fluoride concentrations above 1,000 ppm F-. Four products contained calcium-based abrasive additives. CONCLUSION: The measurement of total and free fluoride concentrations of dentifrices available in The Gambia (West Africa) showed inhomogeneities. This was particularly verified where fluoride compounds were combined with calcium-based abrasives. If so, it is recommended that the total fluoride content should be measured by gas chromatography. Periodic quality control of dentifrices should be introduced in areas with an under-developed consumer-counselling infrastructure.

Class III atraumatic restorative treatment (ART) in adults living in West Africa--outcomes after 48 months.

OBJECTIVES: This observational study assessed the effectiveness of class III restorations using the atraumatic restorative treatment (ART) approach in permanent anterior teeth over a 48-month period. METHODS: Dental auxiliaries placed a total of 117 class III ART restorations in 2004, using a cosmetically improved glass-ionomer (Ionofil® Plus; VOCO, Cuxhafen, Germany), in 67 patients with a mean age of 27.3 years in the rural Jahali Health Center, The Gambia. Independent examiners evaluated the restorations after 24 and 48 months using the clinical ART evaluation criteria. RESULTS: Seventy-six of the restorations could be observed over 48 months in 51 patients. After 48 months, 53 of 76 restorations were classified as clinically acceptable (without or with minor intervention (repair) needed), and 23 restorations were classified as insufficient. There was no statistical difference in a clustered performance rating between restorations placed in central and lateral incisors (P=1.0). CONCLUSIONS: The adoption of the ART approach to class III caries cavities made restorative dental care in anterior teeth available in a West African region. The long-term performance was comparable to other studies. Longitudinal clinical studies with greater populations are required to substantiate these results.

Effects of bleaching agents on human enamel light reflectance.

OBJECTIVES: Tooth whitening has been associated with splitting-up chromogenic molecules by hydrogen peroxides. Though micromorphological alterations are well documented, little is known about optical changes as a function of shifting in wavelengths. Therefore, the aim of the current study was to measure reflectance changes after bleaching in vitro by using a spectrometer. METHODS: Forty-eight enamel slabs (diameter = 5 mm) were prepared from the sound enamel of extracted human teeth that were: 1) fully impacted, 2) from juveniles ages 10 to 16 years, 3) from adults 35 to 45 years of age and 4) from seniors older than age 65. In all specimens, the baseline total reflectance measurement was performed with a computer-assisted spectrometer (Ocean Optics, Dunedin, FL, USA) within wavelengths (wl) from 430 nm to 800 nm. Four enamel samples of each age group were exposed to either 10% or 15% carbamide peroxide (Illuminé Home, Dentsply, Konstanz, Germany) or 35% hydrogen peroxide (Pola Office, SDI Limited, Victoria, Australia). After surface treatment, all slabs underwent total reflectance measurement again. Statistical analysis was calculated at wl 450, 500 and 750 nm using the Student's paired t-test and one-way variance analysis. RESULTS: Total reflectance significantly increased after bleaching at all enamel maturation stages, irrespective of the bleaching agent concentration, for wl 450 nm (blue) and 500 nm (green) with p<0.0001. At 750 nm (red), significant changes only occurred in enamel from adults and seniors (p<0.04). However, the efficacy of bleaching was significantly increased in the blue and green light spectra as compared to the red spectra (p<0.0001). CONCLUSIONS: The results of the current study showed that the exclusive assumption of the "chromophore effect" in dental bleaching could not be sustained, because whitening of the dental enamel works at different maturation stages, even in impacted teeth. This effect is irrespective of the bleaching protocol used and the bleaching agent concentration.

Performance of atraumatic restorative treatment (ART) depending on operator-experience.

OBJECTIVES: Oral 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. METHODS: One 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. RESULTS: There 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). CONCLUSIONS: For 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.

Development of a basic root canal treatment (BRT) for primary oral health care--evaluation after one year.

OBJECTIVES: Atraumatic Restorative Treatment (ART) was a major step forward in community dentistry but treatment options for deep carious lesions or pulp involvement still focus on tooth extraction in under-served areas worldwide. To bridge the gap between ART and extraction this pilot study aimed to develop and follow-up a basic root canal treatment for rural dental health facilities in the Republic of The Gambia (West Africa), faced with an environment lacking technical equipment and developing primary oral health care. METHODS: 25 single rooted teeth with acute irreversible pulpitis were root canal treated with a standardised endodontic instrument kit and a specific procedure. A step-back technique was used with intermittent chlorhexidine 0.2% and saline irrigation. Root canal obturation was performed using a single-cone technique with gutta-percha using Grossman's root canal cement. Coronal filling was carried out by using ART. Clinical examinations were documented before treatment, one day, five days, six months and twelve months postoperatively. RESULTS: None of the root canal fillings had to be revised due to postoperative complications. In 9 out of 25 teeth, transitory apical pain disappeared after a few days. After six months, all ART fillings appeared clinically acceptable, two fillings had to be corrected. Four class II restorations and three class IV restorations needed replacement after 12 months. Patients' assessment of health related quality of life improved significantly, especially concerning dental pain, chewing ability and fitness for work. CONCLUSIONS: Preliminary clinical follow-ups showed encouraging results for the basic root canal treatment approach. Longitudinal clinical studies with greater populations are required to substantiate these results. Modifications in the coronal filling technique are preferable to improve the clinical performance of extended ART cavity restorations.

Fluoride availability from natural resources in The Gambia--implications for oral health care.

INTRODUCTION: Changing food patterns in combination with ineffective oral hygiene measures and insufficient bioavailability of fluoride from drinking water and other sources seem to impair the dental health status in developing countries, especially in the younger population. Therefore, preventive programmes in controlling dental caries progression should be based on local conditions. METHODS: For mapping the drinking water fluoride content throughout The Gambia, samples of water from rural community wells, public water taps, commercial mineral water, and from the Gambia-River were measured. Additionally, fluoride concentrations of locally extracted table salt and green tea were determined. RESULTS: Showed the need for supplementary fluoride intake, because natural dietary fluoride availability is very low. CONCLUSION: Age-related recommendations for oral health care and for additional fluoride bioavailability are given, taking into account local socio-economic conditions in the Republic of The Gambia and similar developing countries.

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-microm 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.

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

BACKGROUND: One 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. METHODS: A 5 x 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. RESULTS: The 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. CONCLUSION: From the results it can be concluded that slightly acidified fluoridated dentifrices may have a certain positive effect on enamel remineralization.

Comparative study of in vitro caries-like lesions and natural caries lesions at crown margins.

PURPOSE: Secondary caries at crown margins and the influence of preparation techniques are major clinical problems. It was therefore the aim of this study to compare natural caries lesions at crown margins with experimental caries lesions. MATERIALS AND METHODS: Five extracted caries-free human molars were restored with gold cast crowns and afterwards covered with wax leaving a 3 x 3 mm window at the crown margin. These teeth were then incubated in acidified gel (pH 4.7) for 50 days. After incubation these teeth and five other crowned extracted teeth exhibiting natural caries lesions were embedded in Technovit 9100. Serial sections with a thickness of 80 microm were cut through the lesions and investigated with polarized light microscopy (PLM) and scanning electron microscopy (SEM) combined with energy dispersive X-ray (EDX) analysis for quantitative element analysis of Ca, P, and C. The results of the quantitative element analysis were statistically evaluated using the nonparametric ANOVA test for repeated measurements. RESULTS: PLM of the experimental lesions showed homogeneous lesions with no transparent zone, or dead tracts. The natural caries lesions exhibited a demineralized zone, translucent zone, and dead tracts. Quantitative element analysis showed a statistically significant difference (p < 0.01) of Ca, P, and C between sound dentin and demineralized dentin in natural and experimental caries lesions. CONCLUSION: The experimental model reproduces the demineralization pattern of secondary caries but does not simulate the vital dentin reactions of peritubular and intratubular mineralization.

Micromorphology of enamel surface after vital tooth bleaching.

The aim of the present study was to assess microroughness changes of enamel surfaces after bleaching procedures with 10% and 16% concentrations of carbamide peroxide by confocal laser scanning microscopy. Twenty caries-free incisors, extracted for periodontitis reasons, were sectioned into two halves of experimental and control specimens. The teeth were divided into two groups, and the experimental specimens were exposed to either 10% or 16% carbamide peroxide for 4 hours per 7 days. Measurements were made at three randomly selected 140 x 100 microm areas of 10 experimental and control specimens per group at the same crown level. Microroughness was measured in "total roughness" (Rt) and "average roughness" (Ra) descriptor values. The statistical analysis showed significantly higher microroughness according to Rt values and Ra values for both groups of carbamide peroxide exposed enamel surfaces.

Micromorphological and micronanalytical characterization of stagnating and progressing root caries lesions.

Root caries is the predominant disease of the tooth tissues in the elderly population and differs in progression and micromorphology from coronal dentin caries. Therefore, different clinical concepts are needed for the treatment of these progressing and arrested lesions. It was the aim of this study to investigate the three-dimensional structure and volume of stagnating and progressing root caries lesions and to determine the mineral composition of the different lesion zones to achieve a better understanding of the natural history of root caries lesion formation. Of 21 extracted human teeth of patients between 42 and 77 years of age with stagnating and progressing root caries lesions serial sections were cut and investigated with polarized light and scanning electron microscopy. From the polarized light micrographs 3D reconstructions were made to determine the volumes of the lesion zones and their relations expressed in a demineralization index (DI). With increasing size of the demineralizing zone the DI increased indicating an increase in the size of the translucent zone. The 3D reconstructions showed distinct differences between stagnating and progressing root caries lesions. In the hypermineralized translucent dentin not all dentin tubules were obliterated by intratubular dentin and within the translucent dentin scattered dead tracts were found. Electron dispersive X-ray (EDX) analysis showed that the intertubular dentin of the translucent dentin was also demineralized to a certain extent. The results indicate distinct morphological differences between progressing and stagnating root caries lesions which may have consequences for treatment strategies.

The in vitro effect of fluoridated milk in a bacterial biofilm--enamel model.

OBJECTIVES: The purpose of this study was to investigate the effect of milk and fluoridated milk on bacterially induced caries-like lesions. SAMPLE AND METHODS: Extracted impacted human molars were cut in half and covered with a varnish leaving a 4*4 mm window. The samples were coated with biofilm of S. sobrinus and were further divided into three experimental groups of S. sobrinus, S. sobrinus and milk and S. sobrinus and fluoridated milk. As negative controls served teeth incubated in saline. Of twenty tooth halves serial ground sections were cut through the lesions and investigated with polarization light microscopy (PLM) and scanning electron microscopy (SEM) and EDX element analysis. The PLM photographs were used for 3D reconstruction, volumetric assessment and determination of the extension of the lesion zones. Of eight tooth halves the biofilm on the enamel surface was studied with SEM and EDX element analysis. RESULTS: Volumetric assessment showed a statistically significant difference in the volume of the body of the lesion and the translucent zone between the milk group and fluoridated milk group. Quantitative element analysis demonstrated significant differences between sound enamel and the superficial layer in the fluoridated milk group. The biofilm on the enamel surface showed an increased Ca content in the milk group and fluoridated milk group. CONCLUSIONS: Milk as a common nutrient seems to play a complex role in in-vitro biofilm--enamel interactions stimulating bacterial demineralization on one hand, and, as effective fluoride carrier, inhibits caries-like demineralization.

Effect of fluoride toothpastes on enamel demineralization.

BACKGROUND: It was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization. METHODS: A 3 x 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). RESULTS: The 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. CONCLUSION: It 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.

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).