Artificial Enamel Lesions Research Articles

The effect of ozone on progression or regression of artificial caries-like enamel lesions in vitro

ObjectiveThis study investigated the effect of ozone on the progression or regression of artificial caries-like lesions on enamel following pH cycling conditions in vitro. MethodsA randomized, single blind, four legs design was used. 20 full thickness enamel slabs were allocated to each of the four groups which were: Fluoride free toothpaste (control); ozone alone; Reductant/Patient Kit alone and a combination of both ozone/Reductant/Patient Kit. Artificial lesions were created and subjected to the pH cycling regime for a 14 days period. Assessments were carried out before and after the pH cycling on the slabs using the microhardness testing and Quantitative Light-induced Fluorescence (QLF). ResultsStatistical significant difference were found in the percentage change of enamel microhardness before and after pH cycling between ozone/Reductant/Patient Kit group and all the other three groups of the study, as well as between Reductant/Patient Kit group and control. There was a statistical significant difference in the change of size and severity of the lesion (ΔQ) between all the three regimes tested and the control with a trend favouring ozone/Reductant/Patient Kit group. ConclusionsIn our model, it appeared that ozone treatment alone is not effective in protecting the enamel against demineralisation or promoting remineralisation, unless combined with the Reductant/Patient Kit, which contain high levels of fluoride.

An in vitro study on the secondary caries-prevention properties of three restorative materials

Secondary caries is considered to be the most important and common reason for the replacement of all types of restorations. The purpose of the study was to evaluate invitro both the anticaries efficacy and marginal integrity of amalgam, glass ionomer cement, and composite resin restorations in a cariogenic condition. Class II cavities were prepared on 60 extracted teeth, which were assigned to 3 groups and restored either with amalgam, glass ionomer, or composite resin. After thermal cycling and sterilization, the teeth were set in an artificial carious environment for 10 days. The bacteria from the margin of the restorations were then collected, and microleakage was evaluated by means of dyeing. According to the locations, the demineralization of tooth tissue around the restoration was divided into 3 parts: artificial outer lesion, artificial enamel wall lesion, and artificial dentin wall lesion. The depths of the artificial outer lesion and the areas of the artificial enamel and dentin wall lesions were investigated with a confocal laser scanning microscope after all the specimens had been stained with 0.1 mM Rhodamine B. Statistical analyses consisted of 1-way ANOVA and Kruskal-Wallis tests (α=.05). No significant difference was noted in terms of the number of bacteria around the restorations for the 3 materials; the microleakage of amalgam was the least among the 3 types of restorations; the outer enamel lesion depth around the glass ionomer cement was the lowest, and the wall lesion area around the amalgam was the smallest. No definite inhibitory effect of fluoride releasing restorative materials (glass ionomer) was apparent on Lactobacillus acidophilus in this study. The amalgam restorations showed the best marginal integrity and the smallest artificial wall lesion among the 3 types of restorations.

Remineralization of Artificial Enamel Lesions by Theobromine

Objective: This study investigated the remineralization potential of theobromine in comparison to a standard NaF dentifrice. Methods: Three tooth blocks were produced from each of 30 teeth. Caries-like lesion was created on each block using acidified gel. A smaller block was cut from each block for baseline scanning electron microscopy imaging and electron-dispersive spectroscopy (EDS) analysis for surface Ca level. A tooth slice was cut from each lesion-bearing block for transverse microradiography (TMR) quantification of baseline mineral loss (Δz) and lesion depth (LD). Then baseline surface microhardness (SMH) of each lesion was measured. The three blocks from each tooth were assigned to three remineralizing agents: (1) artificial saliva; (2) artificial saliva with theobromine (0.0011 mol/l), and (3) NaF toothpaste slurry (0.0789 mol/l F). Remineralization was conducted using a pH cycling model with storage in artificial saliva. After a 28-day cycle, samples were analyzed using EDS, TMR, and SMH. Intragroup comparison of pre- and posttest data was performed using t tests (p < 0.05). Intergroup comparisons were performed by post hoc multistep comparisons (Tukey). Results: SMH indicated significant (p < 0.01) remineralization only with theobromine (38 ± 32%) and toothpaste (29 ± 16%). With TMR (Δz/lD), theobromine and toothpaste exhibited significantly (p < 0.01) higher mineral gain relative to artificial saliva. With SMH and TMR, remineralization produced by theobromine and toothpaste was not significantly different. With EDS, calcium deposition was significant in all groups, but not significantly different among the groups (theobromine 13 ± 8%, toothpaste 10 ± 5%, and artificial saliva 6 ± 8%). Conclusion: The present study demonstrated that theobromine in an apatite-forming medium can enhance the remineralization potential of the medium.

Micro-hardness and mineral loss of enamel lesions after infiltration with various resins: Influence of infiltrant composition and application frequency in vitro

ObjectivesThe aim of this in vitro study was to evaluate the influence of infiltrant composition and application frequency on micro-hardness and lesion progression after resin infiltration of artificial enamel lesions. MethodsIn each of 100 bovine enamel samples, three artificial caries lesions were created (pH=4.95, 50 days). After etching two of the lesions (37% phosphoric acid) specimens were randomly allocated to five infiltrants (four experimental infiltrants with different monomer and solvent compositions and penetration coefficients, and one commercial infiltrant [Icon, DMG]). Lesions were then infiltrated and light-cured, and infiltration repeated afterwards for one of the lesions. Infiltrated samples were cut into halves, with one half being demineralised for further 50 days. Micro-hardness (VHN) and integrated mineral loss (ΔZ) were evaluated at baseline and after second demineralisation. Repeated measures ANOVA and paired t-tests were used to analyse influence of material composition and application frequency on micro-hardness and lesion progression (integrated mineral loss difference ΔΔZ). ResultsResin infiltration significantly increased micro-hardness and reduced lesion progression compared to untreated artificial lesions (p<0.05, t-test). Neither micro-hardness nor lesion progression were significantly influenced by material composition (p>0.05, ANOVA). In contrast, twice application resulted in significantly increased micro-hardness and demineralisation resistance of infiltrated lesions (p<0.05, ANOVA). ConclusionResin infiltration significantly improves micro-hardness and demineralisation resistance of enamel lesions; these effects are significantly enhanced if resins are applied twice. Experimental resins did not outperform the commercial infiltrant. Clinical significanceThis in vitro study demonstrated that resin infiltration significantly increases both micro-hardness and demineralisation resistance of enamel caries lesions. Twice application of the infiltrant seems to increase these effects. In contrast, the composition of the infiltrant had no significant influence on investigated parameters.

Effect of SI-R20401 to remineralize artificial incipient enamel lesions in primary teeth

We evaluated the effectiveness of the experimental surface pre-reacted glass-ionomer coating (SI-R20401) to remineralize artificial enamel lesions in primary teeth. For each of 12 sound primary molars, five regions were assigned, based on whether enamel was unground or ground and whether PRG coating was applied. The teeth were demineralized in 10% EDTA for 7 h and lactic acid solution for 3 days and immersed in artificial saliva (Group 1), demineralizing medium (Group 2) or deionized water (Group 3) for 1 month. DIAGNOdent reading, nanoindentation test and scanning electron microcopy/energy dispersive X-ray analysis were performed. Data were analyzed using analysis of variance and the Fisher protected least significance difference test at α = 0.05. After immersion, a decrease in DIAGNOdent value for the demineralized enamel was observed only in the unground/non-PRG region of Group 1. In the ground/PRG region of Groups 1 and 3, the hardness and Young's modulus at the enamel surface were significantly higher than those at subsurface points. For unground enamel, Ca%, P%, and the Ca/P ratio at the enamel surface of the non-PRG region were significantly lower than those at subsurface points. In Group 2, scanning electron microcopy showed greater demineralization at the unground/non-PRG region compared with the unground/PRG region. Efficacy of SI-R20401 to remineralize the enamel lesions in primary teeth was partially observed, however, to arrest the lesion could not be demonstrated.

Comparative evaluation of remineralization potential of casein phosphopeptide-amorphous calcium phosphate and casein phosphopeptide-amorphous calcium phosphate fluoride on artificial enamel white spot lesion: An in vitro light fluorescence study

World-wide, the contribution of dental caries to the burden of oral diseases is about 10 times higher than that of periodontal disease, the other common oral condition. Owing to its globally high prevalence, dental caries is a "pandemic" disease characterized by a high percentage of untreated carious cavities causing pain, discomfort and functional limitations. Untreated carious cavities; furthermore, have a significant impact on the general health of children and on the social and economic well-being of communities. A surgical approach to the elimination of carious lesion was developed a century ago; this approach was necessary at that time, because there was no valid alternative. The focus in caries has recently shifted to the development of methodologies for the detection of the early stages of caries lesions and the non-invasive treatment of these lesions. The non-invasive treatment of early lesions by remineralization has the potential to be a major advance in the clinical management of the disease. Remineralization of white-spot lesions may be possible with a variety of currently available agents containing fluoride, bioavailable calcium and phosphate and phosphate. This concept bridges the traditional gap between prevention and surgical procedures, which is just what dentistry needs today. The aim of this in vitro study was to evaluate and to compare the remineralization potential of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP) on artificial white spot enamel lesions using the quantitative light fluorescence (QLF). A total of 45 caries-free extracted maxillary first premolars were embedded in acrylic resin. The samples were randomly divided into three groups namely control group, CPP-ACP group and CPP-ACFP group with 15 samples in each group. The samples of each group were subjected to demineralization process for a period of 96 h. The samples were then mounted in the artificial mouth model and subjected to remineralization and pH cycling for a period of 21 days. QLF readings were recorded at the end of demineralization (1st, 7th, 14th and 21st day) and were statistically analyzed. As compared with artificial saliva both CPP-ACP and CPP-ACFP produced significant amount of remineralization of the artificial enamel white spot lesion (P < 0.001), however when the remineralizing effect of CPP-ACP was compared with the remineralizing effect of CPP-ACFP there was no significant difference. Significant amount of remineralization was produced by CPP-ACP and CPP-ACFP only after the 7th day. After the 14th day, the remineralization produced by both CPP-ACP and CPP-ACFP as compared to artificial saliva was non-significant.

Remineralization of artificial caries in primary teeth by grape seed extract: an in vitro study.

Background and aims. Promoting remineralization is the ultimate goal of clinical prevention of caries lesion. The present in vitro study aimed to investigate the effect of grape seed extract (GSE) on artificial enamel caries in primary human teeth. Materials and methods. Seventeen human sound primary incisors were sectioned mesiodistally. The tooth slices were placed in a demineralizing solution for 96 hours at 37ºC and 50% relative humidity to create lesions. The demineralized fragments of each tooth were randomly divided into two case (immersed in GSE solution in phosphate buffer for 8 days) and control (immersed in distilled water) groups. The samples were subsequently evaluated using a scanning electron microscope and a micro-hardness tester. Data were analyzed using independent t-test. Results. The mean ± SD micro-hardness values for the case and control groups were 358.6±83.42 and 296.51± 69.41, respectively. Grape seed extract significantly increased the micro-hardness of the lesions (P=0.03). The morphology of GSE treated enamel was clearly different from that in the control group, and there were deposits of scaffolding insoluble complexes on the enamel surface. Conclusion. GSE enhanced the remineralization process of artificial enamel lesions of primary teeth, and thus, might be considered an effective natural agent in non-invasive dentistry.

Protection of sound enamel and artificial enamel lesions against demineralisation: Caries infiltrant versus adhesive

ObjectiveTo compare the protective potential of a conventional adhesive, a caries infiltrant and a combination of both against acidic challenge in vitro. MethodsOne-hundred-and-fifty discs from bovine lower central incisors were fabricated. Seventy-five samples remained untreated, whereas the other half was subjected to a demineralisation process (14 days, acidic buffer, and pH 5) to create artificial enamel lesions. Specimens were then radioactively irradiated, and each 15 sound and demineralised specimens were treated with a caries infiltrant (Icon, DMG), an unfilled adhesive (Heliobond, IvoclarVivadent) or a combination of infiltrant and adhesive. Specimens treated with the adhesive followed by a flowable composite (TetricEvoFlow, IvoclarVivadent) served as positive control, while untreated specimens served as negative control. All samples were then subjected to lactic acid for 3 weeks at pH 4. Loss of apatite was determined using the radiochemical method of liquid scintillation. Data were statistically analysed by Kruskal–Wallis-test, one-way ANOVA and Scheffe's post hoc tests (p≤.05). ResultsIn both sound enamel and artificial caries lesions, untreated specimens showed the highest rate of apatite loss, whereas enamel treated with the adhesive and the flowable composite showed almost complete protection surface against dissolution. The caries infiltrant, the adhesive and the combination of both were able to decrease enamel dissolution, but the adhesive and the combination of adhesive and infiltrant were more effective than the infiltrant alone. ConclusionWithin the limitations of this in vitro study, the application of an adhesive (alone or in combination with the caries infiltrant) is more effective to protect enamel dissolution than the infiltrant alone.

In vitro study of the effects of fluoride-releasing dental materials on remineralization in an enamel erosion model

ObjectivesThis study was conducted to compare the remineralization effects of five regimens on the loss of fluorescence intensity, surface microhardness, roughness and microstructure of bovine enamel after remineralization. We hope that these results can provide some basis for the clinical application of these materials. MethodsOne hundred bovine incisors were prepared and divided into the following five groups, which were treated with distinct dental materials: (1) Clinpro™ XT varnish (CV), (2) F-varnish (FV), (3) Tooth Mousse (TM), (4) Fuji III LC® light-cured glass ionomer pit and fissure sealant (FJ) and (5) Base Cement® glass polyalkenoate cement (BC). Subsequently, they were detected using four different methods: quantitative light-induced fluorescence, microhardness, surface 3D topography and scanning electron microscopy (SEM). ResultsThe loss of fluorescence intensity of CV, BC and FJ groups showed significant decreases after remineralization (p<0.05). The microhardness values of the BC group were significantly higher than those of the other groups (p<0.05) after 6 weeks of remineralization. The CV group's surface roughness was significantly lower than those of the other groups after 6 weeks of remineralization (p<0.05). Regarding microstructure values, the FV group showed many round particles deposited in the bovine enamel after remineralization. However, the other four groups mainly showed needle-like crystals. ConclusionsGlass ionomer cement (GIC)-based dental materials can promote more remineralization of the artificial enamel lesions than can NaF-based dental materials. Resin-modified GIC materials (e.g., CV and FJ) have the potential for more controlled and sustained release of remineralized agents. The effect of TM requires further study.

Remineralization effects of casein phosphopeptide-amorphous calcium phosphate crème on artificial early enamel lesions of primary teeth

Caries in children younger than 72 months is called early childhood caries (ECC). Sixty-six per cent of Chinese children younger than 5 years old have dental decay, and about 97% of them are untreated. This in vitro study was conducted to evaluate the remineralization effects of the casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) crème on the artificial early enamel lesions of the primary teeth and to assess its caries-prevention efficiency. Enamel specimens with artificial early lesions were produced and were then randomly divided into Group A: distilled and deionized water, DDW, as negative control; Group B: CPP-ACP crème, test group; Group C: 500 ppm NaF solution, as positive control. The enamel surface microhardness (SMH) was measured before, after demineralization, and 30 days after remineralization. The results were analysed with the SPSS 13.0 software package. The enamel specimens were analysed by the scanning electron microscope. The CPP-ACP crème increased SMH of the eroded enamel significantly more than 500 ppm NaF solution did. The morphology of the enamel was different in each group. The CPP-ACP crème is effective in remineralizing early enamel lesions of the primary teeth, a little more effective than 500 ppm NaF and can be used for the prevention of ECC.

An in vitro evaluation of selective demineralised enamel removal using bio-active glass air abrasion

Unnecessary over-preparation of carious enamel often occurs clinically during operative caries management. The working hypothesis to be investigated in this study is the potential for bio-active glass air abrasion to remove selectively only demineralised enamel in artificial enamel lesions when compared to equivalent alumina air abrasion, so potentially minimising cavity over-preparation. Bisected artificial, paired smooth surface enamel lesions on ethics-approved, extracted sound human molars were created and subsequently air abraded with 27μm alumina (n = 19) and bio-active glass (n = 19). The difference between pre-operative lesion boundary and post-operative cavity margin was calculated following optical confocal fluorescent assessment of the lesion boundary. Data indicated mean% over-preparation (sound enamel removal) of 176% with alumina and 15.2% for bio-active glass (p = 0.005). Bio-active glass abrasion removed completely the demineralised enamel from artificial lesions with clinically insignificant over-preparation of sound tissue, indicating technique selectivity towards grossly demineralised enamel. Alumina air abrasion resulted in substantial enamel removal in both sound and demineralised tissues indicating the operator selectivity required to use the techniques effectively in clinical practice.

Effects of Carboxymethyl Cellulose-Based Saliva Substitutes with Varying Degrees of Saturation with Respect to Calcium Phosphates on Artificial Enamel Lesions

The aim of the present study was to evaluate the effects of experimental saliva substitutes based on carboxymethyl cellulose (CMC) differing in degrees of saturation with respect to calcium phosphates on the mineral loss of enamel in vitro. Demineralized bovine specimens (subsurface lesions) were exposed to one of six experimental CMC-based solutions with theoretical degrees of saturation with respect to octacalcium phosphate (S_OCP) of S0, S0.5, S1, S2, S4, and S8 for 10 weeks. A previously studied saliva substitute (Glandosane) and two aqueous solutions (C0 and C1) served as controls. Mineral losses and lesion depths before and after storage were evaluated from microradiographs. Free and bound calcium as well as phosphate and fluoride concentrations were determined. According to these measurements, S_OCP of S2, S4, and S8 was 0.3, 1.1, and 3.4, respectively. Storage in Glandosane and both negative controls resulted in significant demineralization (p < 0.05). Only S2 significantly remineralized the specimens (p < 0.05). All other solutions showed neutral effects. No significant differences in mineralization between S0 and C0 as well as between S1 and C1 could be observed (p > 0.05). It can be concluded that a CMC-based solution actually unsaturated with respect to octacalcium phosphate (S2) shows most pronounced remineralization capability under the conditions chosen. This might be explained by a more favorable balance between calcium bound to CMC in an adsorbed layer at the enamel-liquid interface and heterogeneous nucleation of calcium phosphates within a solution compared to solutions either supersaturated or having lower levels of saturation.

Remineralization of early enamel lesions using casein phosphopeptide amorphous calcium Phosphate: An ex-vivo study

Objective:This study aimed at qualitatively evaluating the remineralization potential of casein phosphopeptide amorphous calcium phosphate on artificial early enamel lesions in an ex-vivo scenario by observing the treated tooth surface using a scanning electron microscope (SEM).Materials and Methods:This randomized study was conducted on 10 subjects undergoing orthodontic treatment with premolar extraction as part of their treatment. Artificial white lesions were created with the application of 37% phosphoric acid for 20 mins. Teeth were then divided into two groups: one experimental and the other control. Customised orthodontic band with a window was luted with intermediate restorative material in the experimental group whereas in the control group, band without a window was luted. The casein phosphopeptide amorphous calcium phosphate (GC TOOTH MOUSSE) paste was then applied on the window region of the experimental group for 3 mins thrice daily after meals for 14 days, whereas no paste was applied in the control group. After 14 days, teeth were extracted and viewed under an SEM.Results:The study groups showed remineralization of the lesions as compared with the control group in most of the samples.Conclusion:Casein phophopeptide could significantly remineralize the artificial enamel lesions in vivo.

Comparison of Cross-Sectional Hardness and Transverse Microradiography of Artificial Carious Enamel Lesions Induced by Different Demineralising Solutions and Gels

The aims of this study were: (1) to correlate surface (SH) and cross-sectional hardness (CSH) with microradiographic parameters of artificial enamel lesions; (2) to compare lesions prepared by different protocols. Fifty bovine enamel specimens were allocated by stratified randomisation according to their initial SH values to five groups and lesions produced by different methods: MC gel (methylcellulose gel/lactic acid, pH 4.6, 14 days); PA gel (polyacrylic acid/lactic acid/hydroxyapatite, pH 4.8, 16 h); MHDP (undersaturated lactate buffer/methyl diphosphonate, pH 5.0, 6 days); buffer (undersaturated acetate buffer/fluoride, pH 5.0, 16 h), and pH cycling (7 days). SH of the lesions (SH₁) was measured. The specimens were longitudinally sectioned and transverse microradiography (TMR) and CSH measured at 10- to 220-μm depth from the surface. Overall, there was a medium correlation but non-linear and variable relationship between mineral content and √CSH. √SH₁ was weakly to moderately correlated with surface layer properties, weakly correlated with lesion depth but uncorrelated with integrated mineral loss. MHDP lesions showed the highest subsurface mineral loss, followed by pH cycling, buffer, PA gel and MC gel lesions. The conclusions were: (1) CSH, as an alternative to TMR, does not estimate mineral content very accurately, but gives information about mechanical properties of lesions; (2) SH should not be used to analyse lesions; (3) artificial caries lesions produced by the protocols differ, especially considering the method of analysis.

Progression of Artificial Enamel Caries Lesions after Infiltration with Experimental Light Curing Resins

The arrest of enamel caries lesions by infiltration with low-viscosity light curing resins might be a promising approach of microinvasive dentistry. However, no materials optimized for rapid lesion infiltration (‘infiltrants’) are commercially available today. The penetration coefficient (PC) of experimental resins has been shown to correlate with penetration speed and, therefore, might be an important feature of infiltrants. The aim of the present study was to evaluate the influence of PC and composition of experimental infiltrants on the progression of enamel lesions in a demineralizing environment. Artificial enamel lesions were prepared in a demineralization solution for 50 days and infiltrated with either one of twelve experimental infiltrants or a commercially available adhesive for 10, 22, and 40 s, respectively. Specimens were cut perpendicularly to the surface and one half of each specimen was exposed to a demineralizing solution for another 50 days, whereas the other half was used as baseline control. Lesion progression was analyzed using confocal microscopy (CLSM) and transversal microradiography (TMR). The square root of the product of PC and application time was negatively correlated with progression of lesion depth (CLSM: r = –0.741; TMR: r = –0.450). Therefore, infiltrants should preferably have high PCs to facilitate inhibition of lesion progression efficiently.

Effect of a 4% titanium tetrafluoride (TiF 4) varnish on demineralisation and remineralisation of bovine enamel in vitro

Objectives This in vitro study assessed the effect of a 4% TiF 4 varnish on demineralisation and remineralisation of sound enamel and artificial carious enamel lesions, respectively. Methods Bovine sound and carious enamel ( n = 110) were randomly allocated to each type of varnish: Duraphat ®-D (NaF, 2.26%F, pH 4.5, Colgate-Brazil, n = 30), Duofluorid ®-F (NaF, 2.71%F, pH 8.0, FGM-Brazil, n = 30), TiF 4–T (2.45%F, pH 1.0, FGM-Brazil, n = 30) and no-fluoride–P (FGM-Brazil, pH 5.0, n = 20). For the formation of artificial enamel caries, half of the blocks were immersed in 32 mL buffer acetate solution (16 h), whereas the other half was maintained sound. The varnishes were applied onto the enamel surfaces. Thus, the samples were subjected to pH cycles (37 °C) for 7 days. The response variables tested were surface and cross-sectional hardness. Data were tested using Kruskal-Wallis test ( p < 0.05). Results All F varnishes significantly reduced demineralisation and increased remineralisation in comparison to placebo. The TiF 4 did not significantly reduce the surface enamel softening when compared with the other F varnishes, but it decreased the loss of subsurface hardness to the same extent. In enamel blocks with previous artificial carious lesions, the TiF 4 significantly improved the rehardening compared to the other varnishes up to 30 μm depth. Conclusions The TiF 4 varnish was able to decrease the demineralisation and increase the remineralisation of previously sound and carious enamel, respectively. It was equally effective compared to NaF varnishes on reducing the demineralisation at subsurface, but it was more effective on improving the remineralisation at surface and subsurface.

Influence of the application time on the penetration of different dental adhesives and a fissure sealant into artificial subsurface lesions in bovine enamel

Sealing of approximal enamel lesions by infiltration with low viscous resins seems to be a promising approach in non-operative dentistry and should bear advantages compared to remineralization or invasive treatment. The aim of this in vitro study was to evaluate the penetration ability of five dental adhesives and a fissure sealant into initial enamel lesions for an application time of either 15 s or 30 s. In each of 54 specimens of bovine enamel, three windows were demineralized for 14 days. Subsequently, two windows were etched with phosphoric acid for 5s in order to degrade the surface layer, whereas one window served as untreated control. The specimens were randomly divided into six groups and a fissure sealant as well as five different adhesives were applied onto the subsurface lesions and allowed to penetrate for either 15 or 30 s. Overlying material was wiped away and the resins were light cured. To visualize the penetrated resins and the remaining pore structures, the specimens were infiltrated with a low viscous fluorescent resin and studied using a Confocal Laser Scanning Microscope (CLSM). For Helioseal, Heliobond, Resulcin Monobond, and Excite an application time of 30s resulted in significantly higher (p < 0.05; t-test) penetration depths (47-105 microm) compared to 15s (29-49 microm). Helioseal, Heliobond, Resulcin Monobond, and Excite are suitable for sealing artificial subsurface enamel lesions in vitro. After an application time of 30 s a significant deeper penetration could be observed for these materials.

Effect of three fluoride agents on remineralization and fluoride uptake on enamel lesion

This study is to compare the fluoride uptake of three fluoride agents and the effect of remineralization on artificial enamel lesions. Eight human third molars were all divided into four slabs. The slabs were randomly assigned to the following four groups: group A (9,040 ppm F, APF gel), group B (968 ppm F, SnF 2 home gel), group C (22,600 ppm F, fluoride varnish, FV) and a control group. After 72-hour demineralizing and 10-day pH-cycling period with the application of corresponding fluorides. The distribution of fluoride and mineral change was analyzed with EPMA and CMR respectively. There was a significant increase in the amount of F uptake after the application of the three fluoride agents compared to the control group. Group A showed an extremely greater F uptake compared to group C and B. The amount of F uptake from group C was greater than that of group B. The three tested groups showed signs of significantly greater amounts of remineralization as compared to the control group. Remineralization of group C was detected to be the greatest, followed by group A and group B, but there was no significant difference in them under statistical analysis. It can be concluded that all of the tested agents were effective in regaining mineral loss. FV may be recommended as a professional topical fluoride. It is as effective, if not more so, as traditionally used APF gel. Also 0.4% SnF 2 home gel is an efficient self-applied topical fluoride for daily use.

Application of a fibre-optic confocal microscope to the detection of artificial enamel lesions

In recent years, fluorescence-based optical methods for detecting dental caries have been examined with some success. However, these methods do not explicitly assess the lesion depth, which may prove to be a useful indicator of the progression/regression of dental caries. The purpose of this study was to apply a newly developed fibre optic-based confocal microscope to the characterisation of artificial enamel lesions in their initial stages. Lesions were found to produce characteristic back-scattering signals, with an initial peak indicating the sample surface and a smaller secondary peak indicating the base of the lesion. Analysis of these signals showed that lesions from as little as 20 to over 100 μm deep could be detected. As the technique incorporates fibre optics to deliver the excitation light and collect the back-scattered light, it is suited to clinical application. Further work is needed to show that this method is applicable to detecting natural lesions in vivo.

EVALUATING THE EFFECTS OF FLUORIDE-RELEASING DENTAL MATERIALS ON ADJACENT INTERPROXIMAL CARIES

The authors examined several restorative materials to evaluate their ability to inhibit demineralization and enhance remineralization of incipient carious lesions on the interproximal enamel of teeth adjacent to those restored with the materials. Twenty-one subjects in need of a crown on a mandibular molar and a Class II inlay on an adjacent tooth took part in this six-phase study. Artificial enamel lesions were created and positioned within the interproximal portion of a crown. Lesions were photographed with polarized light microscopy and characterized before and after 30-day intraoral exposures. Each phase included the placement of a new section in the crown model and a new Class II inlay restorative material in the adjacent tooth. Results demonstrated that nonfluoridated resin composite, fluoridated resin composite and resin-modified glass ionomer restorative materials, when placed in subjects who brushed with a fluoridated dentifrice, demonstrated significantly (P < .05) less enamel demineralization than the nonfluoridated resin composite control placed in subjects who brushed with a nonfluoridated dentifrice. The resin-modified glass ionomer cement, however, even when brushed with a nonfluoridated dentifrice, exhibited significantly (P < .05) less demineralization than the nonfluoridated resin composite control brushed with a nonfluoridated dentifrice. Resin-modified glass ionomer cement appears to significantly inhibit demineralization of interproximal enamel of teeth adjacent to those restored with the material. Resin-modified glass ionomer cement restorations can enhance prevention of enamel demineralization on adjacent teeth.