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PubMedDate not supplied

Remineralizing effects of glass ionomer restorations on adjacent interproximal caries.

The purpose of this study was to examine the in vitro remineralization of incipient caries lesions on teeth adjacent interproximally to teeth with Class II glass ionomer cement restorations. Sixty-four extracted molars were selected and 1 x 5 mm artificial caries lesions were created at the interproximal contact point. One hundred micrometer sections were obtained at the caries sites, and polarized-light photomicrographs were obtained. The sections were covered with varnish, leaving only the external section site exposed, and were placed back into the original tooth. In another sixty-four molars, Class II cavities were prepared. Equal numbers of preparations were filled with Fuji IX GP, Vitremer, Ketac-Molar, or Z 250. These sixty-four teeth were mounted to have interproximal contact with the adjacent teeth containing the artificial caries lesions. Specimens were placed in closed environments of artificial saliva for one month. After thirty days, the same sections were photographed again under polarized light, and areas of the lesions were quantitated. Decrease in the size of caries lesions indicated the glass ionomers had significantly greater remineralization effects on adjacent caries than the nonfluoridated composite resin (ANOVA p < 0.05). There were no significant differences among the three glass ionomers tested.

Analysis of Variance↗

PubMed1997

An in vitro comparison of three fluoride regimens on enamel remineralization.

The purpose of this study was to compare the enamel remineralization effectiveness of a fluoride rinse, fluoridated dentifrice, and fluoride-releasing restorative material. Forty extracted molars had 1 x 5 mm artificial carious lesions formed at the interproximal contact point. One-hundred-micrometer sections were obtained at the caries sites, and polarized light photomicrographs were obtained. The sections had varnish placed, leaving only the external section site exposed, and were situated back into the original tooth. Forty other molars were obtained; 10 had Class-II glass ionomer cement restorations placed. These 40 teeth were mounted to have interproximal contact with the adjacent teeth containing artificial carious lesions. Specimens were placed in closed environments of artificial saliva for 1 month, with saliva being changed every 48 h. Ten specimen pairs were brushed with a fluoridated dentifrice for 2 min, twice per day, 10 specimen pairs were rinsed with a 0.05% sodium fluoride rinse for 1 min twice per day, 10 specimen pairs had Class-II glass ionomer cement restorations positioned adjacent to 10 teeth with artificial carious lesions, and 10 specimen pairs acted as controls. After 30 days, the same sections were photographed again under polarized light, and areas of the lesions were digitized quantitatively. Results demonstrated the mean (+/- SD) remineralization (mu m2) in Thoulet's 1.41 imbibition media to be: lesions adjacent to glass ionomer cement restorations, 2.45 +/- 170; lesions exposed to a fluoridated dentifrice, 223 +/- 102; lesions exposed to 0.05% sodium fluoride rinse, 374 +/- 120, and control lesions only exposed to artificial saliva, 101 +/- 69. Duncan's analysis indicated the fluoridated rinse to have significantly greater remineralization effects on adjacent caries than the other groups (p < or = 0.05). The glass ionomer restorative material and fluoridated dentifrice also had significantly greater remineralization effects on adjacent caries than the control, yet significantly less than the fluoridated rinse (p < or = 0.05).

Analysis of Variance↗

PubMed1997

Fluoride in plaque fluid and saliva after NaF or MFP rinses.

A micro-analytic method, capable of measuring the fluoride concentration in 5 nl of plaque fluid, was used to follow changes in fluoride concentration in saliva and plaque fluid at 6 single tooth-sites in 6 subjects for 180 min after a 0.048 M fluoride rinse as a NaF or MFP (sodium monofluorophosphate) solution. The maximum fluoride concentrations in saliva after NaF was 13x higher than with MFP. About 5% of the total amount of fluoride following the 20 ml NaF rinse was retained in the oral cavity. The corresponding figure followig MFP was <1%. The saliva/plaque fluid fluoride ratios for upper molars and lower incisors were significantly higher than for the upper incisors and lower molars. There was a tendency for a decline in the ratios with respect to time for all sites. To characterize the plaque fluid fluoride intra-oral single-site distribution and clearance, fluoride concentration versus time (AUC) was calculated from 10 to 60 min after a rinse. The NaF AUC followed the order: upper incisor, lower molar, upper molar and lower incisors reflecting a different exposure and clearance pattern due to the different access of the plaque to saliva. The MFP AUC values varied more, but were all significantly lower than the NaF AUC values. Analysis of plaque fluid fluoride curves at various sites revealed an exponential decline in most cases. With NaF, the baseline plaque fluid fluoride levels were not reached within 3 h. It is concluded that NaF solutions result in a significantly higher intra-oral fluoride exposure than MFP solutions. The fluoride distribution and clearance of fluoride from different sites in the oral cavity are linked to salivary access to these sites. These site-specific differences may have clinical consequences with regard to the dynamics of fluoride in the de- and remineralization processes.

Adult↗

PubMed1997

Analytic approaches to longitudinal caries data in adults.

The objective of this paper is to consider current methods for analyzing longitudinal caries data in adults. To illustrate these methods, we used data from the Piedmont dental study, a prospective investigation of the oral health of older adults. Longitudinal dental data sets comprise repeated observations of an outcome (often clustered within randomly selected primary sampling units), and a set of covariates for each of many subjects, in whom clustering can occur as a result of measuring teeth, or surfaces, within people. One objective of statistical analysis is to predict the outcome variable as a function of the covariates, while accounting for the correlation among the repeated observations for a given subject and the effect of clustering within subjects, as well as between subjects within primary sampling units, such as communities, schools, hospitals, or other such units. We considered two statistical approaches: generalized estimating equations and survey regression models. We also examined the impact of varying diagnostic criteria for caries estimation between epidemiologists and clinicians. One approach is to perform the usual time(x) exam score minus time0 score analysis for the baseline and final examinations, while an alternative is to analyze trends among interim examinations. Finally, because caries studies in which the onset of the disease is the endpoint face the problem of censoring due to subject attrition and/or tooth loss, we recommend the incidence density (time-to-event) analytic strategy to address this problem. This approach was found to be most suitable for longitudinal studies of older adults since it accounts for the time each surface remains at risk for the event of interest, making use of interim exam data until the moment the subject and/or the tooth are no longer available for examination. We also included a discussion on biases that occur upon application of the usual methods of estimating caries experience in missing teeth and crowns, which often ignore the classification error in the estimation. We propose a method to adjust for misclassification of the M-component of the DMFS index. In the case where one can observe true reversals or remineralization of caries lesions, we recommend an adjustment formula to account for reversals that are most likely due to examiner misclassification. We provide examples to demonstrate the applicability of the methods for covariates subject to outcome misclassification.

Adult↗

PubMed1992

Orthodontic microabrasive reproximation.

Reproximation (enamel stripping) is described in the literature as a clinical procedure for correction of tooth size deviations. The objective of this study was to qualitatively assess, by means of scanning electron microscopy, (1) the differences exhibited on enamel with mechanical and chemical methods of stripping, and (2) the effect of a synthetic calcifying solution on the etched enamel. Part 1. Sixty human anterior teeth (10 complete sets) that were previously stored in 70% ethanol were subdivided into groups I and II. The teeth in group I were divided into five sets of six teeth mounted in a plaster block in the anterior arch form. Each set was stripped with one of the following mechanical abrasive methods: garnet disks, tungsten carbide and fine diamonds burs, coarse and fine diamond burs, diamond wheel and 3M strips, diamond-coated metal and 3M strips. The teeth in group II were similarly treated, except each set was subjected to a further microabrasive chemical stripping with 37% phosphoric acid used in conjunction with 3M strips. The teeth were then prepared for scanning electron microscopy, viewed, and photographed under magnification. Part 2. Ten human central incisor teeth were etched and used to study the effect of remineralization solutions at various time intervals. The results showed that teeth stripped by routine mechanical abrasive methods exhibited deep furrows and roughness. The teeth that received mechanical and chemical abrasive treatments showed a flattened, etched surface free of furrows. These etched surfaces showed marked crystal growth at 5 and 10 hours after remineralization suggesting the possibility of repair of the chemically altered enamel surface.

Acid Etching, Dental↗

PubMed1998

Use of transverse microradiography to quantify mineral loss by erosion in bovine enamel.

The aim of the present study was to develop transverse microradiography (TMR) in order to quantitatively assess the influence of artificial saliva and orange juice on the erosion of bovine enamel. Bovine incisors were sectioned sagittally into two equal halves. Each half was coated with acid-resistant nail varnish except for a rectangular enamel window on the labial surface of the tooth. While both halves of each tooth were immersed in pure orange juice 6 times daily for a period of 5 min at each occasion making a total of 30 min per day, one half was stored in artificial saliva and the other half in deionized distilled water between exposures to orange juice and for the remaining 12 h overnight, for 24 days making a total of 12 h of exposure to orange juice. Sections bearing intact and eroded enamel surfaces were cut from each specimen and ground to 80 microm thickness, and TMR of the sections was made. Mineral loss was quantified from the microradiographs using two-step image analysis. Mineral loss was significantly greater in those specimens cycled in orange juice and de-ionized distilled water. TMR was used successfully to quantify the mineral loss by erosion in vitro, and it is envisaged that it will be useful for specimens used in intra-oral appliances during in situ trials. Artificial saliva saturated with respect to calcium and phosphate salts can possibly remineralize an erosive lesion and may reduce the degree of erosion.

Analysis of Variance↗

PubMedDate not supplied

Enamel de/remineralization on teeth adjacent to fluoride releasing materials without dentifrice exposure.

Interproximal caries presents a continual clinical concern. The purpose of this study was to evaluate the ability of fluoride-releasing materials to remineralize incipient caries lesions on adjacent teeth, at the interproximal site with and without exposure to a fluoridated dentifrice. Thirty extracted teeth had Class II preparations placed, then equal numbers were restored with amalgam (Tytin (3-Kerr), glass ionomer (Ketac Fil-ESPE) or composite (Heliomolar-Ivoclar). Thirty additional teeth had 1 x 5 mm artificial caries lesions formed at the interproximal contact point. One hundred mu thick sections were obtained at the caries sites and polarized photomicrographs were taken. The sections had varnish placed, leaving only the external section site exposed, and were situated back into the original tooth. These teeth were then mounted with the artificial lesion having an interproximal contact with the adjacent tooth restoration. Specimens were placed in closed environments of artificial saliva for two weeks; the saliva was changed every forty-eight hours. All teeth were cycled through an artificial caries system for thirty minutes, three times per day. Half the specimens in each group were brushed with Crest (Procter and Gamble) for two minutes, twice per day. The same sections were again photographed under polarized light and areas of the lesions were digitized quantitatively. Results demonstrated the mean (+/- S.D.) percent change in lesion size (water imbibition) for each material nonexposed and exposed to fluoridated dentifrice to be: Amalgam -64.1 +/- 22.0, -1.0 +/- 8.5; Glass Ionomer 2.2 +/- 10.6, 14.0 +/- 7.2; Composite -28.1 +/- 11.7, 18.2 +/- 6.7. Negative numbers represent demineralization and positive numbers represent remineralization. Duncan's analysis indicated the nonbrushed fluoride-releasing glass ionomer and composite resin to have significantly greater demineralization inhibition compared to the nonbrushed amalgam group and remineralization enhancement effects on adjacent interproximal lesions (p < 0.05) compared to the brushed amalgam group.

Acrylic Resins↗

PubMed1984

Quantitative microradiographic study of simultaneous demineralization/remineralization of dental enamel in weak acid buffers.

The remineralization behavior of weak acid-treated bovine tooth enamel has been investigated using a recently developed quantitative microradiographic method. Acetate buffer solutions at pH 4.5 containing calcium, phosphate, and 10 ppm fluoride were used in this study. When the solution ion activity product ( KFAP = a10CA a6PO4 a2F ) was 1 X 10(-108), the remineralization of the demineralized region was relatively uniform and complete. On the other hand, when the KFAP was approximately less than or equal to 1 X 10(-112), remineralization of the outer 10-20 micron was incomplete. In addition, for the smaller KFAP solutions there was significant demineralization in the deeper recesses of the originally demineralized region. These results agree with a recent chemical kinetics study in which it was proposed that KFAP = 1 X 10(-112) demarcated the region of solution conditions in which remineralization only occurs from that in which simultaneous demineralization/remineralization takes place. A model consistent with all of the data is proposed.

Acids↗

PubMed2000

Application of quantitative light-induced fluorescence for assessing early caries lesions.

Quantitative light induced fluorescence (QLF) is a nondestructive diagnostic method for the longitudinal assessment of early caries lesions in time. When a tooth becomes carious the fluorescence radiance at the location of the caries lesion decreases. The fluorescence image of enamel with incipient lesions can be digitized and then the fluorescence loss in the lesion can be quantified in comparison to the fluorescence radiance level of sound enamel. Changes in fluorescence radiance and lesion area can be followed in time to measure lesion development. The amount of fluorescence radiance loss is related to the mineral loss in the lesion. The technique can be used in vitro, in situ and in vivo to monitor mineral changes in lesions. Applications of QLF are found in the testing of products designed to inhibit demineralization and promote remineralization of caries. The method has been successfully applied to smooth surfaces as well as occlusal surfaces, but application on approximal lesions is not yet possible.

Cariostatic Agents↗

PubMed2006

Remineralization potential of a fluoridated carbamide peroxide whitening gel.

PURPOSE: Little knowledge exists regarding the potential remineralizing benefits of adding fluoride to carbamide peroxide-based whitening gels. The aim of this project was to evaluate whether a whitening system with fluoride will remineralize previously demineralized enamel. MATERIALS AND METHODS: Twenty-four extracted teeth were sectioned into quadrants labeled A to D. Tooth quadrants in groups A, B, and D were demineralized with a lactic acid, methyl-cellulose gel system to mimic incipient carious lesions. Group C was neither demineralized nor treated. Group D was demineralized, but not treated with a whitening gel. Groups A and B were exposed to one of two commercially prepared 10% carbamide peroxide whitening gels: one that was fluoride free (group A) and one that contained fluoride (0.463%NaF) (group B). Remineralization was evaluated histologically and analyzed statistically using paired t tests accepting p < 0.05 as significant. RESULTS: Shade comparisons showed equal whitening efficacy of both gel A and B. Paired t tests show a significant reduction in lesion depth after treatment with the fluoride containing gel (B: mean lesion depth = 100 microm; p < 0.01), while there was no difference for the gel lacking fluoride (A: mean lesion depth = 110 microm). CONCLUSION: Under the conditions of this study, the addition of fluoride to a tooth whitening system does not affect the gel's whitening efficacy. The addition of fluoride could provide remineralization properties to the gel. As tooth whitening therapies continue to grow and evolve, a strong focus should rest on improving these materials in ways that will provide ever greater patient benefits. Coupling the esthetic benefits of whitening with the preventive benefits of fluoride is a natural step in this direction. CLINICAL SIGNIFICANCE: Therapuetic quantities of fluoride can impact remineralization properties of commercially available tooth whitening gels without altering whitening properties.

Carbamide Peroxide↗

PubMed1996

Fluoride and hard cheese exposure on etched enamel in neck-irradiated patients in situ.

OBJECTIVES: The effect of a fluoride mouth rinse with hard cheese exposure was investigated on rehardening of an etched tooth enamel surface in subjects with radiation-induced hyposalivation in situ. METHODS: Ten patients, six males and four females of mean age 48 years, irradiated with 30 Gy per week for neck and head cancer, volunteered for the present intraoral study. The unstimulated saliva flow rate varied between 0.01 and 0.15 ml min-1. Enamel slabs, approximately 2 mm x 2 mm in size, cut from human molar teeth were embedded in self-curing acrylic resin to fit a microhardness tester. Hardness measurements were carried out on the polished and subsequently etched enamel surface, rinsed for 1 min in the mouth with 10 ml Meridol (GABA INT), containing 0.025% F as amine fluoride and stannous fluoride, and exposed alternatively to mastication of 20 g cheddar cheese for 5 min. RESULTS: Surface erosion of the enamel slabs decreased the mean hardness to a similar degree in all samples. The difference between the mean increased degrees of enamel microhardness following fluoride, fluoride and hard cheese, or repeated fluoride-cheese exposures was significant compared to the etched enamel values. The rate of rehardening derived from a second fluoride-cheese treatment was found to be improved significantly. It seems that the reduced saliva flow in xerostomic patients is sufficient to release bound calcium and phosphate from cheese products. CONCLUSIONS: It is suggested that for xerostomic patients frequent exposures to low-fluoride solutions combined with hard cheese consumption may prevent and remineralize initial demineralization.

Acid Etching, Dental↗

PubMed2004

White lesions after orthodontic treatment: does low fluoride make a difference?

OBJECTIVE: To compare and measure the changes in size of post-orthodontic demineralized white lesion enamel lesions treated with a low fluoride (50 ppm) versus a non-fluoride mouthrinse/toothpaste regime. STUDY DESIGN: An experimental double-blind prospective randomized clinical controlled trial. SETTING: A university dental school orthodontic clinic (Sheffield, UK). PARTICIPANTS: Twenty-six patients identified as having post-orthodontic demineralized white lesions on removal of their fixed appliance. METHOD AND INTERVENTIONS: The participants were randomly and blindly assigned to either a low fluoride mouthrinse/toothpaste treatment regime or an inactive control. Computerized image analysis of calibrated photographic images taken under polarized light were used to measure the lesions. OUTCOME MEASURES: Lesion size and proportion (DWL%t) and percentage reduction (ADPR) at debond, and at 12 and 26 weeks later. RESULTS: Five participants dropped out of the study, 12 had the low fluoride regime and 9 did not. As a percentage of the total labial tooth area (DWL%t) the mean size of the lesions at debond was 8.1% (SD 3.7). After 12 weeks the mean size of lesion had reduced to 4.6% (SD 2.6), which was a significant reduction (p=0.03). After 26 weeks the mean size was 3.5% (SD 2.1), which was a very significant reduction (p<0.003). This confirmed statistically that post-orthodontic demineralized white lesions do reduce in size with time reflecting remineralization or other enamel surface changes. Intervention using a test low fluoride mouthrinse/toothpaste combination at 26 weeks showed an average difference percentage reduction (ADPR) of 54.3% (Upper 95% CI=62.08, Lower 95% CI=46.44%) compared with a non-active control combination, which showed an ADPR of 66.1% (Upper 95% CI=77.74, Lower 95% CI=54.51%). This failed to show any differences or therapeutic affect. CONCLUSIONS: Post-orthodontic demineralized white lesions reduced in size during the 6 months following treatment by approximately half the original size. There was no clinical advantage in using the low fluoride formulation of mouthrinse/toothpaste in this study.

Adolescent↗

PubMed2003

Facial slot Class II restorations: a conservative technique revisited.

Conservative instrumentation of initial posterior approximal caries is beneficial to patients and simplifies surgical management. This article describes a minimally invasive technique for preparing Class II lesions while keeping the marginal ridge and occlusal surface intact. Eradication of caries by minimally invasive techniques and restoration of tooth form after such cavity preparation necessitates specialized restorative materials that feature adhesion to tooth structure and ion exchange to facilitate remineralization. This article outlines a conservative instrumentation sequence, followed by use of a highly viscous, rapid-setting, capsulated glass ionomer cement, for the restoration of initial posterior approximal lesions.

Bicuspid↗

PubMed1997

VariGlass fluoride release and uptake by an adjacent tooth.

PURPOSE: To quantitatively analyze in vitro the fluoride release from proximal VariGlass restorations and resulting uptake by the enamel of adjacent teeth. MATERIALS AND METHODS: Sixty impacted third molars were used and assigned to three groups: C: control, teeth without restorations; RC: teeth with resin composite restorations (Prisma APH); and PMRC: teeth with polyacid-modified resin composite restorations (VariGlass). Each group consisted of four sets of five teeth each. In the latter two sets, by alternating restored and unrestored teeth, the proximal surfaces of three unrestored teeth with an area of exposed enamel were in contact with the restored proximal surfaces of two other teeth. The sets were submitted to high caries challenge conditions with demineralizing and remineralizing solutions for 14 days. The fluoride of each solution and the fluoride uptake were determined and statistical analyses were carried out (ANOVA and Tukey's test). RESULTS: The highest mean fluoride concentration occurred with Group PMRC in both kinds of solutions (P < 0.01), but this value was higher in the demineralizing solution (P < 0.01). Over the 14 days, however, this mean gradually decreased in both solutions (P < 0.01). Group PMRC also showed the highest mean fluoride uptake (P < 0.01), which gradually decreased with depth in the enamel (P < 0.01).

Acrylic Resins↗

PubMedDate not supplied

Demineralization inhibition of direct tooth-colored restorative materials.

This study compared the demineralization inhibition properties of fluoride releasing tooth-colored restorative materials. Materials evaluated included a giomer (Reactmer, Shofu [RM]), a conventional glass ionomer (Fuji II, GC [FJ]), a resin modified glass ionomer (Fuji II LC, GC [FL]) and a compomer (Dyract AP, Dentsply [DY]). A non-fluoride releasing composite (Spectrum TPH, Dentsply [SP]) was used for comparison. Class V preparations on buccal and palatal/lingual were made at the CEJ of 75 freshly extracted molars. The teeth were randomly divided into five groups of 15 and restored with the various materials. The occlusal half of each restoration was in enamel, while the gingival half was in dentin. The restored teeth were stored in distilled water at 37 degrees C for two weeks and subjected to artificial caries challenge (18 hours demineralization [pH 5.0] followed by six hours of remineralization [pH 7.0]) for three days. Sections of 130 +/- 20 microm were examined with a polarized light microscope, and outer lesion depth [OLD] and wall area [WA] lesion/inhibition measurements were made using image analysis software. All data were subjected to statistical analyses at 0.05 significance level. For the various materials, OLD ranged from 54.55 to 65.86 microm and 124.68 to 145.97 microm in enamel and dentin, respectively. WA ranged from -2356.13 to 1398.20 microm2 and -3011.73 to 5095.80 microm2 (positive values indicate wall inhibition, negative values indicate wall lesion) in enamel and dentin, respectively. Results of ANOVA/Scheffe's post-hoc test (p<0.05) were as follows: Enamel OLD--no significant difference between materials; Dentin OLD--SP > FJ, FL & RM; Enamel WA inhibition--FJ, FL & RM > DY & SP and Dentin WA inhibition--FJ > FL > RM > DY > SP. The demineralization inhibition effect of giomers, conventional and resin-modified glass ionomer cements appear to be more evident at the margins of restorations.

Cariostatic Agents↗

PubMed2001

Eroded enamel lesion remineralization by saliva as a possible factor in the site-specificity of human dental erosion.

The composition and flow of saliva, which determine its functions, vary within intraoral sites and among individuals. Also, the susceptibility to tooth erosion reportedly varies among individuals and within the dental arches. A possible effect of saliva on early-eroded lesions may be a contributory factor. The aims here were firstly to determine the remineralization of eroded enamel lesions by saliva, and secondly to investigate any variation of this remineralization within the dental arches and among individuals. Early enamel erosion was produced on human premolars using orange juice. Control sections and two test slabs were cut from each tooth. The two slabs from the same lesion were bonded with composite resins to the palatal surface of upper right lateral incisor teeth and the lingual surface of the lower right lateral incisor teeth of volunteers, who then chewed a sugar-free gum four times daily. After 28-day intraoral exposure, mineral loss (DeltaZ) and lesion depth (ld) were quantified using microradiography and the data analysed by paired t-test (n=10, alpha=0.05). Mean DeltaZ was significantly lower in the group of slabs positioned palatally (P<0.001) and lingually (P<0.001) when compared with the control group, and in the lingually placed group when compared with the palatally positioned (P<0.01). A significantly lower ld was observed in the group of slabs positioned palatally (P<0.05) and lingually (P<0.001) when compared with the control group, and in the lingually positioned group when compared with the palatally placed (P<0.05). It was concluded that saliva can remineralize early enamel erosion, and that the degree of remineralization varies within intraoral sites and may be responsible for the differing susceptibility to erosion within the dental arches.

Adult↗

PubMed2006

The role of erosion, abrasion and attrition in tooth wear.

There is increasing clinical awareness of erosion of enamel and dentine by dietary acids and the consequent increased susceptibility to physical wear. Enamel erosion is characterized by acid-mediated surface softening that, if unchecked, will progress to irreversible loss of surface tissue, potentially exposing the underlying dentine. In comparison, dentine erosion is less well understood as the composition and microstructure are more heterogeneous. Factors which affect the erosive potential of a solution include pH, titratable acidity, common ion concentrations, and frequency and method of exposure. Abrasion and attrition are sources of physical wear and are commonly associated with tooth brushing and tooth-to-tooth contact, respectively. A combination of erosion and abrasion or attrition exacerbates wear; however, further research is required to understand the role of fluoride in protecting mineralized tissues from such processes. Abrasive wear may be seen in a wide range of patients, whereas attritive loss is usually seen in individuals with bruxism. Wear processes are implicated in the development of dentine hypersensitivity. Saliva confers the major protective function against wear due to its role in pellicle formation, buffering, acid clearance, and hard tissue remineralization. This review focuses on the physiochemical factors impacting tooth wear.

Dental Enamel↗

PubMed1999

Current concepts on the theories of the mechanism of action of fluoride.

The caries-preventive effect of fluoride is mainly attributed to the effects on demineralization/remineralization at the tooth oral fluids interface. Sub ppm levels of fluoride in saliva are effective in shifting the balance from demineralization, leading to caries, to remineralization. This is attributed to the fluoride-enhanced precipitation of calcium phosphates, and the formation of fluorhydroxyapatite in the dental tissues. Low fluoride levels are found in saliva after toothbrushing with fluoride containing dentifrices. Similar concentrations are ineffective in interfering with processes of growth and metabolism of bacteria, and also do not result in a significantly reduced dissolution of tooth mineral as a result of (firmly bound) fluoride incorporation. Comparative studies of fluoride efficacy have shown that higher concentrations in solution are needed in pH-cycling studies of dentine than in enamel to maintain the mineral balance or to induce remineralization. This is attributed to the greater solubility of the dentine and the smaller size of the dentine crystallites compared to enamel. Fluoride slow-release devices, in the form of fluoride-releasing restorative materials, may serve to increase the fluoride levels in saliva and plaque to levels at which caries can be prevented, also in high-risk patients. Research questions for the next millennium and future perspectives for fluoride applications should be found in the retention and slow release of fluoride after various combinations of fluoride treatment, the combination of fluoride and anti-microbial treatment, the individualization of caries prevention, and the combination of preventive schemes with new developments in caries diagnosis.

Cariostatic Agents↗