Subsurface Enamel Research Articles

Effects of probiotic fermented milk on biofilms, oral microbiota, and enamel.

The aim of this study was to evaluate in vitro and in vivo the effects of 2 brands of probiotic fermented milk on biofilms, oral microbiota, and enamel. For the in situ experiment, ten volunteers wore palatine devices containing four blocks of bovine dental enamel over 3 phases, during which 20% sucrose solution, Yakult® (Treatment A), and Batavito® (Treatment B) were dropped on the enamel blocks. Salivary microbial counts were obtained and biofilm samples were analyzed after each phase. For the in vivo experiment, the same ten volunteers drunk Yakult® (Treatment C) and Batavito® (Treatment D) in two phases. Saliva samples were collected for microbial analysis after each phase. The in situ study showed that in comparison with Treatment A, Treatment B resulted in fewer total cultivable anaerobes and facultative microorganisms in biofilms, higher final microhardness, lower percentage change in surface hardness, and smaller integrated subsurface enamel hardness. In the in vivo study, Treatment D resulted in a reduction in the counts of all microorganisms. The results suggested that the probiotic fermented milk Batavito®, but not Yakult®, reduced the amount of oral microorganisms and mineral loss in bovine enamel.

Evaluation of resin-enamel interface micromorphology in respect of different Er,Cr:YSGG laser parameters

AbstractBackground and objective:Enamel irradiation with an erbium,chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser has been reported to cause micromorphological alterations within resin-enamel interfaces and subsurface enamel. The present study was conducted to evaluate the effects of different output power/pulse repetition rate parameter combinations of Er,Cr:YSGG laser on the micromorphology of resin-enamel interfaces and subsurface enamel.Materials and methods:Thirty-five bovine incisors were used in the present study. Er,Cr:YSGG laser was used on enamel with different output power/pulse repetition rate parameter combinations as follows: 6 W/20 Hz, 6 W/35 Hz, 6 W/50 Hz, 3 W/20 Hz, 3 W/35 Hz, 3 W/50 Hz. Following adhesive and composite procedures, specimens were sectioned and either acid-etched with 37% phosphoric acid for 1 min or immersed in 55% nitric acid for 12 h. Then the resin-enamel interfaces were investigated by scanning electron microscopy (SEM).Results:Micromorphological findings by SEM revealed that when enamel surfaces were irradiated with all 6-W groups and 3 W/20 Hz-combinations, large resin structures indicating subsurface microcracks were generally evident within interfaces and subsurface enamel. However, when irradiated with 3 W/35 Hz and 3 W/50 Hz-combinations, the observed resin-enamel interfaces were similar to those of the acid-etched only group.Conclusion:Deploying Er,Cr:YSGG laser with lower power and high pulse repetition rate combinations may reduce damage to resin-enamel interfaces and subsurface enamel. However, assessment of the relationship between these findings and bond strength requires further study.

The effect of a bioglass paste on enamel exposed to erosive challenge

ObjectivesThe current study is evaluating the effect of using a 45S5 bioglass paste and topical fluoride application on the cross sectional micro-hardness and the chemical surface changes of eroded enamel. MethodsEnamel discs were obtained from the buccal surface of one hundred extracted human non-carious third molars. The enamel surfaces were ground flat and each disc was coated with two layers of acid resistant nail varnish except for an exposed treatment window (3mm×2mm) on the buccal surface of the tooth. All specimens were challenged for 60min by orange juice (Tropicana, Chicago, USA) pH 3.85+0.5. The specimens were divided into four groups: the 45S5 bioglass paste group, fluoride gel group (5min application), fluoride gel group (24h application) while the rest of specimens served as control. The cross-sectional micro-hardness of 20 specimens from each group was measured. Five specimens from each group had their top eroded enamel surfaces examined by SEM-EDS. One-way ANOVA was used to compare the cross-sectional micro-hardness of the three groups p<0.05. Results45S5 bioglass paste application significantly improved the sub-surface eroded enamel when compared to fluoride and control specimens (p<0.05). Conclusion45S5 bioglass paste can efficiently improve the micro-hardness of the sub-surface eroded enamel surface. Clinical significanceThe use of the 45S5 Bioglass paste can be used efficiently as a potent remineralizing agent for the sub-surface enamel lesions resulting from erosive challenges.

Clinical cross-polarization optical coherence tomography assessment of subsurface enamel below dental resin composite restorations.

A newly designed intraoral swept source cross-polarization optical coherence tomography (CP-OCT) imaging system was used to examine the integrity of the subsurface enamel below resin composite restorations placed in primary teeth. CP-OCT analysis was performed using images obtained from resin composite restoration in 62 ([Formula: see text]) pediatric subjects. Clinical examination was performed by a single examiner prior to CP-OCT imaging and analysis. CP-OCT images are presented using a unique combined intensity image, where a false color scale is overlaid on the grayscale intensity image. There was a clear difference in the distribution of the mean-backscattered intensity (mR) between restorations recently placed and those possessing frank cavitation (Student's t-test, [Formula: see text]). For mR above 15.49dB, the sensitivity was 80% and specificity 86%. The Youden index J was 0.8 above 12.3dB where sensitivity was 100% and specificity was 80%. CP-OCT imaging may be used to confirm the subsurface marginal integrity below resin composite restorations but with careful consideration of limitations of the imaging modality. CP-OCT imaging may be a useful adjunct to clinical visual investigation to confirm that a composite margin has a sound and well-adapted interface.

The Effect of McInnes Solution on Enamel and the Effect of GC Tooth Mousse on Bleached Enamel: AnIn VitroStudy

The aim is to evaluate the effect of McInnes bleaching agent on the microhardness of enamel before and after bleaching and to evaluate the effect of G C Tooth Mousse on the bleached enamel surface for its microhardness. The materials and methods used are McInnes bleaching solution, Casein phosphopeptide-amorphous calcium phosphate CCP-ACP (G C Tooth mousse) artificial saliva (Dept. of Oral Pathology, GDC Bellary), deionized water, Vickers’ Micro Hardness tester (Zwick/ZHV, Germany), freshly extracted teeth, cold cure acrylic, Diamond disc (Horico–PFINGST New Jersey, USA, KAVO-Germany), straight handpiece (kavopecareta) and plastic moulds (6.5 × 2 mm2). The purpose of this study was to evaluate and compare microhardness of the sound enamel surface by Vickers’ Hardness Number (VHN) before and after bleaching with McInnes solution, and to evaluate the effect of casein phosphopeptide amorphous calcium phosphate (G C Tooth Mousse) on the bleached enamel surface for its microhardness. The data obtained from the test were subjected for statistical analysis and are presented as range, mean and standard deviation. P value of 0.05 or less was considered for statistical significance. The changes in microhardness at different times of assessment were analyzed using the paired ‘t’ test. The results of all the samples showed decrease in the microhardness after two cycles of bleaching, though immediately after bleaching the decrease in the microhardness was not significant (P = 0.34). However, after the second cycles, it showed a significant decrease (P<0.01) in the microhardness. After application of remineralization solution (GC Tooth mousse), the samples showed a marginal increase in the microhardness (P<0.05) after seven days and a marked increase after fourteen days (P<0.001).McInnes bleaching agent does decrease the microhardness of enamel by causing enamel demineralization and GC Tooth mousse used in the study causes an increase in the microhardness of bleached enamel by maintaining a high gradient of calcium and phosphate ions at the enamel subsurface.

Chemical alteration by tooth bleaching of human salivary proteins that infiltrated subsurface enamel lesions--experimental study with bovine lesion model systems.

Salivary macromolecules infiltrate white and brown spot enamel lesions and adsorb onto hydroxyapatite. Calcium-binding salivary proteins such as statherin hinder remineralization of these lesions. We assessed whether bleaching agents can remove salivary components that have infiltrated and bound to experimental subsurface lesions in bovine enamel prepared by immersing specimens in acid and then human saliva. Transversal microradiography showed that such demineralized lesions mimicked incipient carious lesions. Bound proteins to the experimental and untreated control specimens were eluted in a stepwise manner with phosphatebuffered saline, 0.4 M phosphate buffer, and 1 M HCl. SDS-PAGE of dialyzed extracts showed that specific salivary proteins bound to the lesions, while virtually no protein bands were detected if the specimens were bleached. Western blotting showed that even statherin, which was more firmly bound than other proteins, was removed. In-office bleaching agent may be useful in treating enamel lesions for removing proteins bound to these lesions.

An in Vitro Evaluation of Remineralization Potential of Novamin(®) on Artificial Enamel Sub-Surface Lesions Around Orthodontic Brackets Using Energy Dispersive X-Ray Analysis (EDX).

To evaluate and compare the Ca/P ratio of enamel samples around the orthodontic brackets for time periods of 0, 2 and 10 days in two groups (control group and study group). Forty extracted teeth were randomly divided into control group and study group. All samples were demineralized and incubated in artificial saliva at 37°C for a period of 10 days after demineralization. During this phase the enamel samples in the study group were treated with remineralizing paste (NuproNusolution containing Novamin®-Dentsply) for 10 days. At the end of the incubation period, Ca/P ratios were analyzed for both the groupsby EDX analysis. Data obtained was subjected to statistical analysis using student t-test for paired samples and Student t- test for individual samples (p ≤ 0.05). It was found that the mean Ca/P ratio was significantly lower for the control group as compared to the study group (p-value < 0.05) after 10 d of incubation. Novamin(®) containing remineralization toothpaste showed significant remineralizing potential in inhibition of artificial enamel sub-surface lesion around bracket after 10 days of remineralization phase. EDX element analysis was found to be an efficient method to quantify the changes in mineral content of a sample during in vitro caries studies.

Numerical Modelling of Tooth Enamel Subsurface Lesion Formation Induced by Dental Plaque

Using a one-dimensional mathematical model that couples tooth demineralisation and remineralisation with metabolic processes occurring in the dental plaque, two mechanisms for subsurface lesion formation were evaluated. It was found that a subsurface lesion can develop only as the result of alternating periods of demineralisation (acid attack during sugar consumption) and remineralisation (resting period) in tooth enamel with uniform mineral composition. It was also shown that a minimum plaque thickness that can induce an enamel lesion exists. The subsurface lesion formation can also be explained by assuming the existence of a fluoride-containing layer at the tooth surface that decreases enamel solubility. A nearly constant thickness of the surface layer was obtained with both proposed mechanisms. Sensitivity analysis showed that surface layer formation is strongly dependent on the length of remineralisation and demineralisation cycles. The restoration period is very important and the numerical simulations support the observation that often consumption of sugars is a key factor in caries formation. The calculated profiles of mineral content in enamel are similar to those observed experimentally. Most probably, both studied mechanisms interact in vivo in the process of caries development, but the simplest explanation for subsurface lesion formation remains the alternation between demineralisation and remineralisation cycles without any pre-imposed gradients.

Effect of a sugar-free pediatric antibiotic on primary tooth enamel hardness when exposed to different sucrose exposure conditions in situ

This in situ study aimed to investigate the effect of a sugar-free antibiotic suspension containing amoxicillin and clavulanic acid on enamel hardness of human primary teeth simulating different conditions of cariogenic challenge. A crossover, partially double-blind study was conducted in three phases of 14 days each, during which 11 volunteers wore palatal devices containing six dental enamel blocks covered with plastic meshes to allow biofilm formation. Dental blocks were extraorally submitted to treatment with a 20 % sucrose solution at three different daily frequencies of exposure (0, 3, and 8 times/day), and to the antibiotic suspension or its excipients at an 8-h time interval application regimen. On the 14th day of each phase, the blocks were removed for enamel analysis (surface and cross-sectional microhardness--SMH and CSMH). The antibiotic suspension showed significant higher SMH and CSMH values than the excipients (p < 0.05; Wilcoxon), regardless of the frequency of sucrose exposure. Sucrose exposure did not account for further enamel demineralization both for antibiotic and excipients (p > 0.05; Friedman). A protective effect of the antibiotic suspension on enamel demineralization was verified because its excipients alone promoted more pronounced surface and subsurface enamel demineralization, even in the absence of sucrose exposure. The use of a sugar-free amoxicillin/clavulanic acid suspension may promote a protective effect on primary enamel demineralization probably due to its topical effect on dental biofilm.

Effect of low fluoride acidic dentifrices on dental remineralization

This study evaluated the capacity of fluoride acidic dentifrices (pH 4.5) to promote enamel remineralization using a pH cycling model, comparing them with a standard dentifrice (1,100 µgF/g). Enamel blocks had their surface polished and surface hardness determined (SH). Next, they were submitted to subsurface enamel demineralization and to post-demineralization surface hardness analysis. The blocks were divided into 6 experimental groups (n=10): placebo (without F, pH 4.5, negative control), 275, 412, 550, 1,100 µgF/g and a standard dentifrice (positive control). The blocks were submitted to pH cycling for 6 days and treatment with dentifrice slurries twice a day. After pH cycling, surface and cross-sectional hardness were assessed to obtain the percentage of surface hardness recovery (%SHR) and the integrated loss of subsurface hardness (ΔKHN). The results showed that %SHR was similar among acidic dentifrices with 412, 550, 1,100 µgF/g and to the positive control (Tukey's test; p>0.05). For ΔKHN, the acidic dentifrice with 550 µg F/g showed a better performance when compared with the positive control. It can be concluded that acidic dentifrice 550 µgF/g had similar remineralization capacity to that of positive control.

Remineralization of Demineralized Enamel via Calcium Phosphate Nanocomposite

Secondary caries remains the main problem limiting the longevity of composite restorations. The objective of this study was to investigate the remineralization of demineralized human enamel in vitro via a nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP). NACP were synthesized by a spray-drying technique and incorporated into a dental resin. First, caries-like subsurface enamel lesions were created via an acidic solution. Then, NACP nanocomposite or a commercial fluoride-releasing control composite was placed on the demineralized enamel, along with control enamel without a composite. These specimens were then treated with a cyclic demineralization/remineralization regimen for 30 days. Quantitative microradiography showed typical enamel subsurface demineralization before cyclic demineralization/remineralization treatment, and significant remineralization in enamel under the NACP nanocomposite after the demineralization/remineralization treatment. The NACP nanocomposite had the highest enamel remineralization (mean ± SD; n = 6) of 21.8 ± 3.7%, significantly higher than the 5.7 ± 6.9% for fluoride-releasing composite (p < 0.05). The enamel group without composite had further demineralization of −26.1 ± 16.2%. In conclusion, a novel NACP nanocomposite was effective in remineralizing enamel lesions in vitro. Its enamel remineralization was 4-fold that of a fluoride-releasing composite control. Combined with the good mechanical and acid-neutralization properties reported earlier, the new NACP nanocomposite is promising for remineralization of demineralized tooth structures.

Optimization of calcium concentration of saliva with phosphoryl oligosaccharides of calcium (POs-Ca) for enamel remineralization in vitro

ObjectivePhosphoryl oligosaccharides of calcium (POs-Ca) are highly soluble calcium source made from potato starch. The aim of this study was to investigate the optimal concentrations of POs-Ca for the remineralization of subsurface enamel lesions in vitro. DesignDemineralized bovine enamel slabs (n=5) were remineralized in vitro for 24h at 37°C with artificial saliva (AS) containing 0–0.74% POs-Ca to adjust the Ca/P ratio to 0.4–3.0, then sectioned and analysed by transversal microradiography (TMR). The data were analysed by Scheffe's post hoc test. The Ca/P ratio with most remineralization was used to investigate the effect of calcium on enamel remineralization (n=11). The demineralized slabs were treated with AS with calcium-chloride- (CaCl2-) or POs-Ca with an identical calcium content, and sectioned for TMR and wide-angle X-ray diffraction (WAXRD) analyses to evaluate the local changes in hydroxyapatite (HAp) crystal content. The data were analysed using the Mann–Whitney U-test. ResultsThe highest mineral recovery rate resulted from addition of POs-Ca to adjust the Ca/P to 1.67. At this ratio, the mineral recovery rate for AS containing POs-Ca (24.2±7.4%) was significantly higher than that for AS containing CaCl2 (12.5±11.3%) (mean±SD, p<0.05). The recovery rate of HAp crystallites for AS containing POs-Ca (35.7±10.9%) was also significantly higher than that for AS containing CaCl2 (23.1±13.5%) (p<0.05). The restored crystallites were oriented in the same directions as in sound enamel. ConclusionsPOs-Ca effectively enhances enamel remineralization with ordered HAp at a Ca/P ratio of 1.67.

Effect of hydration on assessment of early enamel lesion using swept‐source optical coherence tomography

Establishing reproducible methodologies for assessment of early enamel lesions using optical coherence tomography (OCT) appears to be challenging. This in vitro study longitudinally evaluated the subsurface enamel lesion progression after 3, 9 and 15 days by cross-sectional scanning using 1310 nm centered swept-source OCT (SS-OCT) under hydrated and dry conditions. The positive difference between the depth-integrated OCT signals at dry and hydrated conditions were calculated and adopted as dehydration parameter (DH). A linear regression was found between DH and the square root of demineralization time (R(2) = 0.99). Significant differences were found in DH between sound and demineralized enamel, and between different periods of demineralization (p < 0.001). Hydration state affects the reflectivity of demineralized porous enamel, and the effect can be potentially used for assessment of early enamel lesion using OCT.

Characteristic Changes of Enamel Surface Layer Following Demineralization of Remineralized Enamel Subsurface Lesion

Characteristic Changes of Enamel Surface Layer Following Demineralization of Remineralized Enamel Subsurface Lesion

Effect of Chewing Gum Containing Calcified Seaweed on Remineralization and Acid Resistance of Enamel Subsurface Lesions

Calcified seaweed contains abundant quantities of calcium, magnesium, phosphate, sodium and fluorine ions. The objective of this study was to investigate the effect of chewing gum containing calcified seaweed on the remineralization and aciduric properties of enamel. For intraoral experiments, enamel blocks prepared from third molars were attached to an appliance. Each block was covered with acid-resistant nail varnish, except for a window measuring 6 x 4 mm. A caries-like lesion was artificially prepared in the window. Participants attached the appliance and chewed gum for 20 min, 4 times a day. The intraoral experiment period was 2 weeks. Half of each window was re-covered with nail varnish. In the aciduric experiment, these blocks were immersed in demineralizing solution. After demineralization, the blocks were embedded in polyester resin and prepared in ground sections. Contact microradiograms of these ground sections were obtained. A high degree of remineralization occurred at the surface and at a deep layer in the remineralized enamel area. In the aciduric experiment area, further demineralization was observed beneath the original demineralized layer, and overall depth of demineralization increased. A thin, highly mineralized layer was observed between the two demineralized layers. The degree of remineralization and aciduric rate with calcified seaweed treatment was higher than that with non-calcified seaweed treatment (p‹0.05). These results suggest that chewing calcified seaweed-containing gum significantly enhances the remineralization and acid resistance of enamel by exposure to fluorine ions.

Demineralization effects of phosphoric acid on surface and subsurface bovine enamel bleached with in-office hydrogen peroxide.

To measure the demineralization capacity of 37% phosphoric acid on surface and subsurface bovine enamel after bleaching with hydrogen peroxide (H2O2). Three equally-sized sections with 16 mm2 of exposed enamel surface were obtained from the enamel of 10 bovine incisors. One specimen sample from each crown was assigned to one of three groups (n = 10): group I, no bleaching agent; group II, bleached with 38% H202 for 20 min; or group III, 30% H202 for 60 min. After 24 h, the thickness of specimens was measured and they were immersed in 37% phosphoric acid solution, of which 5-ml aliquots were collected at 30 s and 60 s. Specimens were then ground to a depth of 25 μm and again immersed in 37% phosphoric acid solution. This procedure was repeated for enamel depths of 50 and 100 μm. Ca2+ concentrations in the phosphoric acid aliquots were measured by atomic absorption spectroscopy. No significant differences were found in the total amounts of extracted Ca2+ between bleached and unbleached specimens (F = 0.142; p = 0.869). The amount of Ca2+ extracted was similar among the four depth levels in the unbleached and in the 30% H202 bleached specimens. A significantly larger amount of Ca2+ was obtained at 25 μm depth (subsurface) from specimens treated with 38% H202. Pre-bleaching with 38% H202 significantly increased the decalcifying effect of phosphoric acid on subsurface enamel at a depth of 25 μm compared to 100 μm, whereas pre-bleaching with 30% H202 did not modify this effect at any level.

Surface substance loss of subsurface bovine enamel lesions after different steps of the resinous infiltration technique: a 3D topography analysis

Surface substance loss of subsurface enamel lesions before (baseline/demineralization) and after each step of the infiltration technique was evaluated by means of a three-dimensional focus variation. Eighty enamel specimens were prepared and partially varnished (control). Non-varnished areas were demineralized (pH 4.95; 28 days), and etched with phosphoric acid gel (20%; 5 s). Specimens were randomly assigned to eight groups (n = 10), and were infiltrated using four resinous materials. In subgroups 1, polymerization and finishing with abrasive polishing strips followed. In subgroups 2, excess material was removed before polymerization (E1/E2-Excite, Vivadent; F1/F2-Fortify, Bisco; G1/G2-Glaze & Bond, DMG; I1/I2-Icon, DMG). Topometrical evaluation revealed a negligible substance loss of demineralized enamel. After etching, mean (±SD) differences of height decreased uniformly (-6.6 ± 2.0 μm; p = 0.089; ANOVA). For infiltrated lesions, DH of subgroups 1 was comparable to the etched lesions, with a significant increase (compared to etched lesions) in subgroups 2 (1.1 ± 0.1 μm; p < 0.001; t test). Within the limitations of this study, it is concluded that etching of initial subsurface lesions will result in significant surface substance loss; removal of excess material before light-curing should simplify the infiltration procedure, and this will avoid any abrasion resulting from polishing procedures.

Effect of CPP–ACP addition on physical properties of zinc oxide non-eugenol temporary cements

Objectives Casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) is a milk derivative which holds nanoclusters of calcium and phosphate ions. The presence of CPP–ACP has been found to reduce demineralization and enhance remineralization in subsurface enamel and in dentin. Incorporation of CPP–ACP into luting cements has not been investigated. The aim of this study was to determine the effect on the physical properties of two commercially available zinc oxide non-eugenol temporary luting cements with incorporation of up to 8% (w/w) CPP–ACP. Methods Setting time, compressive strength, diametral tensile strength, film thickness and solubility tests were investigated for 0, 0.5, 1.0, 2.0, 3.0, 4.0 and 8.0% (w/w) CPP–ACP incorporated into Freegenol™ and Temp-Bond ® NE. Tests were carried out based on ISO 3107 requirements. Results Compressive and diametral tensile strengths progressively decreased with increasing concentrations of up to 8.0% (w/w) CPP–ACP incorporated into both Freegenol™ and Temp-Bond ® NE. Setting time was delayed beyond ISO requirements. Film thickness was not adversely affected. Increased solubility of Temp-Bond ® NE with 8.0% (w/w) CPP–ACP incorporation suggested an effect of the CPP–ACP on this property for this cement. Significance The incorporation of up to 8.0% (w/w) CPP–ACP into two zinc oxide non-eugenol luting cements has no adverse effects on the film thickness, compressive strength and diametral tensile strength of the cements investigated. Solubility investigations suggest that CPP–ACP leaches out of the zinc oxide non-eugenol luting cements into an aqueous environment.

Saliva Substitutes in Combination with Highly Concentrated Fluorides and Brushing: In vitro Effects on Enamel Subsurface Lesions

Hyposalivation is often associated with high caries activity, in particular in patients undergoing irradiation in the head/neck area. Besides the use of saliva substitutes to relieve the oral symptoms, daily application of fluoride gels or toothpaste (5,000 µg F^–/g) is recommended for caries prevention. The aim of this study was to evaluate potentially remineralising effects of these fluoride agents in combination with saliva substitutes on enamel subsurface lesions. Demineralised bovine specimens were either stored in mineral water [control; saturation with respect to octacalcium phosphate (S_OCP): 0.8], a demineralising saliva substitute (Glandosane; S_OCP: 0.3) or in a modified (with respect to S_OCP) saliva substitute [Saliva natura (SN); S_OCP: 1.9] for 5 weeks (37°C). The following treatments were applied twice daily (11–13/group): no treatment (0), ProSchmelz fluoride gel (PS; 10 min application), Duraphat toothpaste (DP; 10 s; brushing with toothpaste/storage solution slurry), combination of DP+PS. Mineral parameters before/after storage were evaluated from microradiographs. Storage in Glandosane led to significant demineralisation (p < 0.05; paired t test), whereas additional use of fluoride agents neutralised the demineralising effect (p > 0.05). Storage in water alone resulted in no changes in mineral parameters (p > 0.05), whereas in combination with fluorides remineralisation could be shown (p < 0.05). For SN alone, remineralisation was observed (p < 0.05), but no additional beneficial effects of fluorides were detected. Under the conditions chosen, the fluoride agents reduce the demineralising effects of Glandosane and promote the remineralisation of specimens stored in water. Remineralising effects of SN could not be enhanced by the fluorides.

Surfactant-modified β-TCP: structure, properties, and in vitro remineralization of subsurface enamel lesions

A hybrid material comprised of beta-tricalcium phosphate (beta-TCP) and sodium lauryl sulfate (SLS) was prepared using a mechanochemical process, examined using particle size analysis, IR spectroscopy, (31)P, (23)Na, and (13)C solid-state NMR spectroscopy, and calcium dissolution experiments, and probed for in vitro remineralization of subsurface enamel lesions. Our results suggest that while the (31)P environments of beta-TCP remain unchanged during solid-state processing, there is noticeable shifting among the SLS (23)Na and (13)C environments. Therefore, given the structure of beta-TCP, along with our IR examinations and calcium dissolution isotherms, SLS appears to interface strongly with the cation deficient C(3) symmetry site of the beta-TCP hexagonal crystal lattice with probable emphasis placed on the underbonded CaO(3) polyhedra. To demonstrate the utility of the surface-active TCP material in dental applications, we combined the TCP-SLS with 5,000 ppm F (NaF) and evaluated the remineralization potential of subsurface enamel lesions via an in vitro remineralization/demineralization pH cycling dental model. Using surface and longitudinal microhardness measurements, the TCP-SLS plus 5,000 ppm F system was found to significantly boost remineralization of subsurface enamel lesions, with microhardness values increasing up to 30% greater than fluoride alone.