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Different formulas of topical fluoride have been used to manage root carious lesions. This clinical trial aimed to investigate the efficacy of a dental varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride compared with fluoride alone in reversing/arresting root caries in xerostomic patients over 1 year. A total of 80 patients (age range 45–92 years) with primary root caries (n = 184 root carious lesions) and unstimulated salivary flow rate of <0.2 mL/min were randomly allocated to receive either dental varnish containing CPP-ACP and 5% fluoride (group 1: MI varnish; GC, Japan) (n = 41, 83 lesions), or dental varnish with 5% fluoride alone (group 2: NUPRO White; Dentsply, USA) (n = 39, 101 lesions). Clinical assessments with Severity Index (SI) for root caries, DIAGNOdent measurements, and varnish application were carried out at baseline, 3, 6, and 12 months. Standard oral hygiene instructions with 1,450 ppm fluoride toothpastes were provided for both groups. After 3 months, 63.9% (n = 46) of root caries in group 1 became hard (SI: 0) compared with 39.3% (n = 35) in group 2 (p < 0.01). After 6 and 12 months, the differences in SI were insignificant (group 1, n = 60, 83.3%) (group 2, n = 66, 74.2%) (p = 0.36), and (group 1, n = 60, 89.6%) (group 2, n = 67, 81.7%, n = 1 soft, 1.2%) (p = 0.29), respectively. In both groups, noncavitated leathery lesions were more likely to become hard when compared to the cavitated root caries. A significant decrease in plaque index, surface roughness, lesion dimension, and DIAGNOdent readings with a significant increase in lesion distance from the gingival margin was reported in both groups (p < 0.05). This study has provided evidence that fluoride dental varnish either with or without calcium and phosphate has the potential to arrest/reverse root caries, especially noncavitated lesions for patients with xerostomia. [ABSTRACT FROM AUTHOR]

Remineralisation of demineralised enamel subsurface lesions can be enhanced by pretreatment of the lesions with base (NaOH). The aim of this study was to test the effect of intralesion pH modulation on remineralisation of demineralised enamel subsurface lesions by casein phosphopeptide-stabilised amorphous calcium fluoride phosphate (CPP-ACFP) in vitro. Two remineralisation models were utilised, the first involving 60-min cyclic pH modulation for 105 h and the second involved short-term cyclic pH modulation (12-min cycle, 240 min total duration) compared with the equivalent time of continuous treatment (200 min total duration). The intralesion pH modulation was achieved by cyclic exposure to a pH 12.9 NaOH solution and a CPP-ACFP remineralisation solution at pH 5.5. Percent remineralisation was assessed using transverse microradiography with data statistically analysed using a 2-sample Student t test. For the first model, the intralesion pH modulation group had significantly (p < 0.001) higher remineralisation (43.8 ± 6.9%) than the control group (28.2 ± 5.8%) cycled with water. For the second model, the intralesion pH modulation group had significantly (p < 0.001) higher remineralisation (23.1 ± 3.4%) than the group with continuous equivalent CPP-ACFP treatment time (1.9 ± 1.3%). In both models, intralesion pH modulation significantly accelerated remineralisation, and this was attributed to the effect pH modulation had on the diffusion gradients of ions/ion pairs and the degree of saturation with respect to apatite phases within the lesion fluid. [ABSTRACT FROM AUTHOR]

The Nyvad classification is a visual-tactile caries classification system devised to enable the detection of the activity and severity of caries lesions with special focus on low-caries populations. The criteria behind the classification reflect the entire continuum of caries, ranging from clinically sound surfaces through noncavitated and microcavitated caries lesions in enamel, to frank cavitation into the dentin. Lesion activity at each severity stage is discriminated by differences in surface topography and lesion texture. The reliability of the Nyvad criteria is high to excellent when used by trained examiners in the primary and permanent dentitions. The Nyvad criteria have construct validity for lesion activity assessments because of their ability to reflect the well-known caries-controlling effect of fluoride. Predictive validity was demonstrated by showing that active noncavitated lesions are at higher risk of progressing to a cavity or filled state than do inactive noncavitated lesions. Lesion activity assessment performed successfully as a screening tool to identify individuals with a poor caries prognosis. Because of their predictive validity, the Nyvad criteria are superior to other current caries lesion descriptors for the detection of changes in the lesion activity status over time. The Nyvad criteria fulfill all the formal requirements for a robust caries lesion classification and are recommended for evidence-based caries management in clinical practice and in research. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of pH on the activation of matrix metalloproteinases (MMPs) of human coronal (CD) and radicular dentin (RD). CD and RD were pulverized to powder, and proteins were extracted with 1% phosphoric acid. The extracted proteins and the demineralized powder were separately incubated in the following solutions: 4-aminophenylmercuric acetate (control) or a buffer solution at different pHs (2.5, 4.5, 5.0, 6.0, and 7.0). After incubation, proteins were separated by electrophoresis to measure MMP activities by zymography. To assess the solubilized dentin collagen, the demineralized dentin powder was sustained in incubation buffer, and the amount of hydroxyproline (HYP) released was measured. Zymography revealed MMP-2 gelatinolytic activities for CD and RD in all experimental groups. For both substrates, the lowest pH solutions (2.5, 4.5, and 5.0) yielded higher gelatinolytic activity than those obtained by the highest pH solutions (6.0 and 7.0). For HYP analysis, no detectable absorbance values were observed for pHs of 2.5 and 4.5. The amount of HYP was higher for pH 7.0 than those of all other groups (p < 0.05), except for pH 6.0. No statistical differences were found between pHs 6.0 and 5.0 and control (p > 0.05). The MMP-2 enzyme from human CD and RD is dynamically influenced by pH: at low pH, the extracted enzyme activates this latent form, whereas collagen degradation by the matrix-bound enzyme is only observed when pHs are close to neutral. [ABSTRACT FROM AUTHOR]

The application of a self-assembling peptide on noncavitated caries lesions is supposed to be a feasible approach to facilitate remineralization and mask their unfavorable appearance. However, demineralizing conditions are common in the oral environment, so the aim of this pH-cycling study was to compare recommended and novel treatment methods regarding their ability to hamper demineralization and as a consequence mask artificial enamel caries lesions. Artificial caries lesions were prepared in bovine enamel and randomly allocated to 11 groups (n = 22). Treatments before pH-cycling were as follows: the application of a self-assembling peptide (Curodont™ Repair [C]), a low-viscosity resin (Icon® [I]), 2 fluoride solutions (10,000 ppm F-: Elmex fluid [E] and 43,350 ppm F-: Tiefenfluorid® [T]), and no intervention (N). During pH-cycling (28 days, 6 × 60 min demineralization/day) half of the specimens in each group were brushed (10 s; 2 ×/day) with either fluoride-free (named e.g., C0) or NaF (1,100 ppm F-; e.g., C1) dentifrice slurry. In another subgroup specimens were pH-cycled but not brushed (NNB). Differences in integrated mineral loss (ΔΔZ), lesion depth (ΔLD), and colorimetric values (ΔΔE) were calculated between values after pre-demineralization, surface treatment, and pH-cycling. Specimens of C0, C1, NNB, N0, N1, T0, and E0 showed significantly increased ΔZ and LD values after pH-cycling (p ≤ 0.003; paired t test). C0, C1, NNB, and N0 showed significantly higher changes in ΔΔZ than E1, I0, I1, and T1 (p < 0.001; ANOVA). Significantly reduced colorimetric values could only be observed for I1, I0, E1, and E0 after treatment and after pH-cycling (p ≤ 0.027; paired t test). In conclusion, under the conditions chosen only the application of a low-viscosity resin could mask caries lesions significantly, whereas self-assembling peptides could neither inhibit lesion progression nor mask the lesions considerably. [ABSTRACT FROM AUTHOR]

High fluoride dentifrice (FD; 5,000 ppm F) has been recommended to arrest root dentine lesions and to control enamel caries in high-risk patients. Also, standard FD (1,100 ppm F) in combination with professional fluoride application has been recommended to control dentine caries, but the effect of this combination on enamel has been considered modest. Considering the lack of evaluation comparing the use of 5,000 ppm FD (5,000-FD) versus acidulated phosphate fluoride (APF) application combined with 1,100 ppm FD (1,100-FD) on the inhibition and repair of caries lesions in both enamel and dentine, we conducted this in situ, double-blind, crossover study of 3 phases of 14 days. In each phase, 18 volunteers wore palatal appliances containing enamel and root dentine specimens, either sound or carious, to evaluate the effect of the treatments on the inhibition or repair of caries lesions, respectively. The treatments were non-FD (negative control), 5,000-FD, or 1 APF gel application on dental specimens combined with 1,100-FD used twice per day (APF + 1,100-FD). The reduction of demineralization and enhancement of remineralization were assessed by surface and cross-sectional hardness. Fluoride concentration was determined on dental specimens and on the formed biofilm. For enamel, APF + 1,100-FD and 5,000-FD did not differ regarding the inhibition of demineralization and repair of caries lesions. However, for dentine the difference between these treatments was inconclusive because while APF + 1,100-FD was more effective than 5,000-FD in caries lesion reduction and repair, 5,000-FD was more effective than APF + 1,100-FD in the reduction of surface demineralization. Therefore, the findings show that the combination of APF + 1,100-FD is as effective as 5,000-FD in enamel inhibition of demineralization and enhancement of remineralization. [ABSTRACT FROM AUTHOR]

Recent advances regarding the caries process indicate that ecological phenomena induced by bacterial acid production tilt the de- and remineralization balance of the dental hard tissues towards demineralization through bacterial acid-induced adaptation and selection within the microbiota - from the dynamic stability stage to the aciduric stage via the acidogenic stage [Takahashi and Nyvad, 2008]. Dentin and root caries can also be partly explained by this hypothesis; however, the fact that these tissues contain a considerable amount of organic material suggests that protein degradation is involved in caries formation. In this review, we compiled relevant histological, biochemical, and microbiological information about dentin/root caries and refined the hypothesis by adding degradation of the organic matrix (the proteolytic stage) to the abovementioned stages. Bacterial acidification not only induces demineralization and exposure of the organic matrix in dentin/root surfaces but also activation of dentin-embedded and salivary matrix metalloproteinases and cathepsins. These phenomena initiate degradation of the demineralized organic matrix in dentin/root surfaces. While a bacterial involvement has never been confirmed in the initial degradation of organic material, the detection of proteolytic/amino acid-degrading bacteria and bacterial metabolites in dentin and root caries suggests a bacterial digestion and metabolism of partly degraded matrix. Moreover, bacterial metabolites might induce pulpitis as an inflammatory/immunomodulatory factor. Root and dentin surfaces are always at risk of becoming demineralized in the oral cavity, and exposed organic materials can be degraded by host-derived proteases contained in saliva and dentin itself. New approaches to the prevention and treatment of root/dentin caries are required. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this double-blinded, randomized, cross-over in situ study was to evaluate the re- and demineralization characteristics of sound enamel as well as lowly and highly demineralized caries-like enamel lesions after the application of different fluoride compounds.Methods: In each of three experimental legs of 4 weeks, 21 participants wore intraoral mandibular appliances containing 4 bovine enamel specimens (2 lowly and 2 highly demineralized). Each specimen included one sound enamel and either one lowly demineralized (7 days, pH 4.95) or one highly demineralized (21 days, pH 4.95) lesion, and was positioned 1 mm below the acrylic under a plastic mesh. The three randomly allocated treatments (application only) included the following dentifrices: (1) 1,100 ppm F as NaF, (2) 1,100 ppm F as SnF2 and (3) 0 ppm F (fluoride-free) as negative control. Differences in integrated mineral loss (x0394;x0394;Z) and lesion depth (x0394;LD) were calculated between values before and after the in situ period using transversal microradiography.Results: Of the 21 participants, 6 did not complete the study and 2 were excluded due to protocol violation. Irrespectively of the treatment, higher baseline mineral loss and lesion depth led to a less pronounced change in mineral loss and lesion depth. Except for x0394;x0394;Z of the dentifrice with 0 ppm F, sound surfaces showed significantly higher x0394;x0394;Z and x0394;LD values compared with lowly and highly demineralized lesions (p < 0.05, t test).Conclusion: Re- and demineralization characteristics of enamel depended directly on baseline mineral loss and lesion depth. Treatment groups should therefore be well balanced with respect to baseline mineral loss and lesion depth. [ABSTRACT FROM AUTHOR]

The authors also report data suggesting that patients with hematological malignancies may be disqualified from receiving intensive treatment; hence, treating hematologists should be alert to this possibility and clarify the baseline disease prognosis to encourage ICU care when appropriate. Hence, physicians treating COVID-19 patients with hematological malignancy should be aware of the limited generalizability of data on therapeutic options for this population [[4]]. The number of COVID-19 cases worldwide has crossed 400 million cases as for February 2022. [Extracted from the article]

Objective: To assess the anti-caries effect of arginine-containing formulations in vivo on caries lesions compared with fluorides or placebo.Methods: Randomized or quasi-randomized human clinical trials wherein arginine was delivered by any method were considered. The MEDLINE, Web of Science, EMBASE, Cochrane Library, and CBM databases were searched to identify relevant articles published up to December 2014. Grey literature was also searched. Two authors performed data extraction independently and in duplicate using data collection forms. Each included study was assessed using the Cochrane risk of bias assessment tool.Results: Of the 470 studies screened, 31 full articles were scrutinized and assessed for eligibility. Ten studies (n = 15,546 participants) were selected for final inclusion. The meta-analysis results (n = 7 studies) demonstrated a synergistic effect of arginine when used in conjunction with fluoride on early coronal and root caries compared with placebo or fluoride alone. No specific side effects related to arginine usage were identified.Conclusions: When used in combination with a calcium compound and fluoride, arginine potentially provides a superior anti-caries effect compared with matched formulations of fluoride alone. However, the level of evidence was downgraded because of risks of bias and potential publication bias. In the future, more high quality, non-industry-supported clinical studies in this research area are required before any definitive recommendations can be made. [ABSTRACT FROM AUTHOR]

The purpose of this clinical trial was to evaluate the effect of 1 year of daily application of 10% w/v CPP-ACP (casein phosphopeptide-amorphous calcium phosphate) paste in addition to regular toothbrushing with fluoridated toothpaste on the remineralization of enamel carious lesions in preschool children using quantitative light-induced fluorescence (QLF). A total of 103 Thai children (aged 21/2-31/2 years) with high caries risk who had at least 1 enamel carious lesion (ICDAS 1-3) on the labial surface of the upper anterior teeth were assigned to receive either CPP-ACP paste (n = 53) or placebo control (n = 50) following toothbrushing with fluoridated toothpaste after lunch at school. QLF measurement was performed at baseline, 6 months and 1 year. At 1 year, a significant reduction in fluorescence loss (ΔF), lesion area and lesion volume (ΔQ; p ≤ 0.001) of the lesions were found over time in both groups. However, no significant difference was observed between the groups (p = 0.79, 0.98 and 0.88, respectively). There was no statistically significant difference between the odds of ΔQ transition to a stage of regression or arrest compared with progression from baseline to 1 year between the two groups (OR = 1.03, 95% CI 0.31-3.39). The daily application of 10% w/v CPP-ACP paste on a school day for 1 year resulted in no improvement of enamel carious lesion remineralization in the primary upper anterior teeth as assessed by QLF. The lesion improvement was not superior to remineralization from regular toothbrushing with fluoridated toothpaste alone in these children. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Demineralization in dentinal caries and erosion exposes dentine organic matrix. This exposed matrix, containing type I collagen and non-collagenous proteins, is then degraded by host collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins. The knowledge of the identities and function of these enzymes in dentine has accumulated only within the last 15 years, but has already formed a field of research called 'dentine degradomics'. This research has demonstrated the role of endogenous collagenolytic enzymes in caries and erosion development. In demineralized dentine, the enzymes degrade triple-helical collagen molecules, leading to the gradual loss of collagen matrix. Even before that, they can cleave off the terminal non-helical ends of collagen molecules called telopeptides, leading to the structural changes at the intramolecular gap areas, which may affect or even prevent intrafibrillar remineralization, which is considered essential in restoring the dentine's mechanical properties. They may also cause the loss of non-collagenous proteins that could serve as nucleation sites for remineralization. Here we review the findings demonstrating that inhibition of salivary or dentine endogenous MMPs and cysteine cathepsins may provide preventive means against the progression of caries or erosion. Furthermore, we also suggest the future directions for the new experimental preventive research to gain more knowledge of the enzymes and their function during and after dentine demineralization, and the pathways to find the clinically acceptable means to prevent the functional activity of these enzymes. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The study investigated the erosion/abrasion-preventing potential of experimental NaF (1,400 ppm F-) and amine fluoride (AmF)/NaF/SnCl2/chitosan (1,400 ppm F-, 3,500 ppm Sn2+, 0.5% chitosan) toothpastes relative to placebo and SnF2 gel (970 ppm F-, 3,000 ppm Sn2+), and the impact of the demineralised dentine matrix on toothpaste effects. The study was a cyclic erosion/intervention experiment (10 days). Samples were stored in mineral salt solution either without or with collagenase (from Clostridium histolyticum type VII; 100 U/ml) for continuous removal of the organic matrix. To produce a comparable order of tissue loss, erosion was performed 6 × 30 s/day with 0.5% citric acid in the latter and 6 × 90 s/day with 1% citric acid in the former. Intervention was toothpaste slurry immersion (2 × 2 min/day); half of the samples were additionally brushed for 15 s within this time (brushing machine, load 200 g). Tissue loss was determined profilometrically (mean ± SD; µm). Tissue loss values (without/with brushing) for placebo, NaF, AmF/NaF/SnCl2/chitosan and SnF2 gel, respectively, were 11.6 ± 3.1/12.2 ± 2.5, 12.7 ± 3.1/10.7 ± 4.5, 8.7 ± 2.1/9.7 ± 2.1 and 8.8 ± 1.8/ 10.9 ± 1.8 in the presence of the organic matrix and 10.7 ± 3.2/11.9 ± 2.1, 8.2 ± 4.0/10.1 ± 4.1, 8.7 ± 2.9/9.1 ± 1.8 and 8.4 ± 1.9/7.5 ± 1.5 in the absence of the organic matrix. Relative to placebo, the NaF formulation had no significant effects; the AmF/NaF/SnCl2/chitosan formulation significantly reduced tissue loss between 20 and 25% except when applied without brushing in the absence of the organic matrix. The effects of the formulations were similar both in the presence and absence of the organic matrix. Sn2+/F-- containing formulations have the potential to reduce erosion/abrasion even in the absence of demineralised collagen; seeking for more effective formulations is desirable. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aim: To evaluate caries prevalence in non-syndromic patients with cleft lip and/or palate (CLP) in comparison with a matched non-CLP population. Methods: A literature search was conducted in order to identify articles reporting on the prevalence of caries in CLP versus non-CLP individuals. The related citations function in PubMed and reference lists of retrieved articles were used to expand the search. Only studies with a suitable matched control group were included. From each included study, study and sample characteristics were extracted, as were results. The main outcome was the score given for caries prevalence in each study, using a well-defined index. The data were entered into meta-analysis software and a meta-analysis performed using the random-effects model. Results: From the 592 articles initially identified, 7 were chosen according to preset inclusion and exclusion criteria. All of the studies were cross-sectional in nature, and used the decayed, missing, and filled (DMF/dmf) indices as the final outcomes. The included studies involved a total of 474 CLP patients aged 1.5-29 years. When looking at permanent teeth, data from 5 studies suggest that CLP patients have a higher number of DMF teeth than the controls (mean difference 1.38; p = 0.003). For deciduous teeth, data from 4 studies suggest that CLP patients have a higher number of dmf teeth than the controls (mean difference 1.51; p = 0.03). Conclusion: Non-syndromic patients with CLP tend to have higher caries prevalence, both in the permanent and the deciduous dentition, in comparison with matched non-CLP controls. [ABSTRACT FROM AUTHOR]

Aim: To evaluate caries prevalence in non-syndromic patients with cleft lip and/or palate (CLP) in comparison with a matched non-CLP population. Methods: A literature search was conducted in order to identify articles reporting on the prevalence of caries in CLP versus non-CLP individuals. The related citations function in PubMed and reference lists of retrieved articles were used to expand the search. Only studies with a suitable matched control group were included. From each included study, study and sample characteristics were extracted, as were results. The main outcome was the score given for caries prevalence in each study, using a well-defined index. The data were entered into meta-analysis software and a meta-analysis performed using the random-effects model. Results: From the 592 articles initially identified, 7 were chosen according to preset inclusion and exclusion criteria. All of the studies were cross-sectional in nature, and used the decayed, missing, and filled (DMF/dmf) indices as the final outcomes. The included studies involved a total of 474 CLP patients aged 1.5-29 years. When looking at permanent teeth, data from 5 studies suggest that CLP patients have a higher number of DMF teeth than the controls (mean difference 1.38; p = 0.003). For deciduous teeth, data from 4 studies suggest that CLP patients have a higher number of dmf teeth than the controls (mean difference 1.51; p = 0.03). Conclusion: Non-syndromic patients with CLP tend to have higher caries prevalence, both in the permanent and the deciduous dentition, in comparison with matched non-CLP controls. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the predictive power of several clinical baseline parameters and the de-/remineralisation properties of in vivo etched sites measured with quantitative light-induced fluorescence (QLF) for subsequent 2-year caries increment. At baseline, in 44 children (8.23 ± 1.5 years) two areas (diameter 2 mm) of the buccal surface of a primary posterior tooth were etched with 36% phosphoric acid gel for 1 and 4 min, respectively. The etched sites were analysed immediately after etching (ΔQ1) and 24 h (ΔQ2) later by QLF. Additionally, caries status (deft/DMFT and initial caries), approximal plaque, bleeding on probing, and the patient's current use of fluorides were recorded. In the 2-year follow-up, 29 children were re-assessed. After clinical examination, the caries increment was calculated (ΔDMFT) and correlated with the baseline clinical variables and the QLF readings. Results showed a significant positive correlation between ΔQ1 min and the ΔDMFT (r = 0.44, p = 0.02). The ΔDMFT was significantly correlated with the baseline deft (r = 0.56, p = 0.002), cavitated active caries lesions (r = 0.52, p = 0.003), and filled teeth (r = 0.53, p = 0.003). In a regression analysis the use of fluoridated salt (SC = -0.10) and fluoride gel (SC = -0.14) were negatively associated with ΔDMFT. In conclusion, these findings suggest that the demineralisation properties of the etched sites and the outcome of the 24-hour measurements with QLF are significantly associated with caries increment. Previous caries experience strongly correlated with caries increment in this group of children. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The advantages, limitations and potential applications of available methods for studying erosion of enamel and dentine are reviewed. Special emphasis is placed on the influence of histological differences between the dental hard tissue and the stage of the erosive lesion. No method is suitable for all stages of the lesion. Factors determining the applicability of the methods are: surface condition of the specimen, type of the experimental model, nature of the lesion, need for longitudinal measurements and type of outcome. The most suitable and most widely used methods are: chemical analyses of mineral release and enamel surface hardness for early erosion, and surface profilometry and microradiography for advanced erosion. Morphological changes in eroded dental tissue have usually been characterised by scanning electron microscopy. Novel methods have also been used, but little is known of their potential and limitations. Therefore, there is a need for their further development, evaluation, consolidation and, in particular, validation. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

It is known that some metal salts can inhibit matrix metalloproteinase (MMP) activity, but the effect of iron has not been tested yet. On the other hand, it has recently been suggested that MMP inhibition might influence dentine erosion. Based on this, the aims of this study were: (1) to test in vitro the effect of FeSO4 on MMP-2 and -9 activity, and (2) to evaluate in situ the effect of FeSO4 gel on dentine erosion. MMP-2 and -9 activities were analysed zymographically in buffers containing FeSO4 in concentrations ranging between 0.05 and 1.5 mmol/l or not. Volunteers (n = 10) wore devices containing bovine dentine blocks (n = 60) previously treated with the following gel treatments: FeSO4 (1 mmol/l FeSO4), F (NaF 1.23%; positive control) and placebo (negative control). The gels were applied once and removed after 1 min. Erosion was performed extraorally with Coca-Cola 4 times per day for 5 min over 5 days. Dentine wear was evaluated by profilometry. The data were analysed by Kruskal-Wallis and Dunn’s tests (p < 0.05). FeSO4 inhibited both MMP-2 (IC50 = 0.75 mmol/l) and MMP-9 (IC50 = 0.50 mmol/l) activities. In the in situexperiment, the mean wear (± SD) found for the F gel (0.79 ± 0.08 μm) was significantly reduced in more than 50% when compared to the placebo gel (1.77 ± 0.33 μm), but the FeSO4 gel completely inhibited the wear (0.05 ± 0.02 μm). Since FeSO4 was able to inhibit MMP in vitro, it is possible that the prevention of dentine wear by the FeSO4 gel in situ might be due to MMP inhibition, which should be investigated in further studies. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Erosion of dentine causes mineral dissolution, while the organic compounds remain at the surface. Therefore, a determination of tissue loss is complicated. Established quantitative methods for the evaluation of enamel have also been used for dentine, but the suitability of these techniques in this field has not been systematically determined. Therefore, this study aimed to compare longitudinal microradiography (LMR), contacting (cPM) and non-contacting profilometry (ncPM), and analysis of dissolved calcium (Ca analysis) in the erosion solution. Results are discussed in the light of the histology of dentine erosion. Erosion was performed with 0.05 M citric acid (pH 2.5) for 30, 60, 90 or 120 min, and erosive loss was determined by each method. LMR, cPM and ncPM were performed before and after collagenase digestion of the demineralised organic surface layer, with an emphasis on moisture control. Scanning electron microscopy was performed on randomly selected specimens. All measurements were converted into micrometres. Profilometry was not suitable to adequately quantify mineral loss prior to collagenase digestion. After 120 min of erosion, values of 5.4 ± 1.9 μm (ncPM) and 27.8 ± 4.6 μm (cPM) were determined. Ca analysis revealed a mineral loss of 55.4 ± 11.5 μm. The values for profilometry after matrix digestion were 43.0 ± 5.5 μm (ncPM) and 46.9 ± 6.2 (cPM). Relative and proportional biases were detected for all method comparisons. The mineral loss values were below the detection limit for LMR. The study revealed gross differences between methods, particularly when demineralised organic surface tissue was present. These results indicate that the choice of method is critical and depends on the parameter under study. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aim was to assess the validity of laser fluorescence (LF), visual inspection and surface texture on root caries lesions in vitro, related to histological lesion depths. Agreement on interdevice, interexaminer and intra-examiner levels as well as the influence of discolouration and surface texture on LF readings were investigated. Calibrated examiners assessed lesion colour and surface texture and performed measurements with 2 LF devices in 3 separate series at intervals of 1 week. Sections (300 μm thick) of 64 out of 93 teeth were obtained and examined under the microscope. Lesion depth was assessed with 2 references: from the delineated borderline of the original exposed root surface (ref. I), or if loss of surface continuity, the absolute lesion depth (ref. II). The correlation (Spearman ρ) between LF readings and histological depth was low with values ranging from 0.22 (p > 0.05) to 0.31 (p < 0.05). LF 1 and LF 2 were significantly correlated with discolouration (ρ = 0.52 and 0.46, respectively) and with surface texture denoted as hard (ρ = 0.34 and 0.33, respectively). A significant correlation between colour and histological depth ref. I (ρ = 0.51) and ref. II (ρ = 0.56) was found. No significant correlation between surface texture and histological depth was found. The reliability, evaluated as intraclass correlation coefficient was for intra-examiner 0.99, interexaminer 0.97 and interdevice level 0.98. Large differences were found between 2 consecutive measurements, and high measurement errors indicated considerable deviation of individual measurements. Based on these findings, the LF device is not suitable as a diagnostic tool for root caries. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Blood coagulation appears to play an important role in the occurrence of cancer and its effects may be twofold. First, in patients with cancer, blood coagulation is activated in the direction of a prothrombotic state. Second, a procoagulant environment may promote cancer in different ways. In this chapter we discuss some of the mechanisms that may be involved in this interplay between coagulation and cancer. Blood coagulation proteins interact with cells in the vasculature to maintain hemostasis. However, many proteins that are involved in coagulation and anticoagulation, as well as fibrinolysis, are also found in extravascular tissues. In different organs, these proteins may be involved in cell-signaling mechanisms, through interaction with cell receptors like protease-activated receptors (PARs). Such interactions may drive inflammation, angiogenesis and cell proliferation. The potential procarcinogenic actions of proteases like thrombin may be counteracted by the anticoagulant and anti-inflammatory actions of the protein C-thrombomodulin mechanism. In the blood of cancer patients, the balance is usually shifted towards a procoagulant direction. The resulting excess thrombin- and fibrin-forming activity promotes venous thrombosis and may in the extravascular compartment stimulate cancer progression. The activation of platelets and their interaction with leukocytes may propagate this process. In addition to the therapeutic modulation of the prothrombotic environment, the induction of specific anticoagulant proteins including thrombomodulin may have effects on tumor growth or dissemination, but the nature of these effects still remains hard to predict. The interplay between cancer and blood coagulation merits further experimental and clinical research. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse possible associations between caries increments and selected caries determinants in children with type 1 diabetes mellitus and their age- and sex-matched non-diabetic controls, over 2 years. A total of 63 (10–15 years old) diabetic and non-diabetic pairs were examined for dental caries, oral hygiene and salivary factors. Salivary flow rates, buffer effect, concentrations of mutans streptococci, lactobacilli, yeasts, total IgA and IgG, protein, albumin, amylase and glucose were analysed. Means of 2-year decayed/missing/filled surface (DMFS) increments were similar in diabetics and their controls. Over the study period, both unstimulated and stimulated salivary flow rates remained significantly lower in diabetic children compared to controls. No differences were observed in the counts of lactobacilli, mutans streptococci or yeast growth during follow-up, whereas salivary IgA, protein and glucose concentrations were higher in diabetics than in controls throughout the 2-year period. Multivariable linear regression analysis showed that children with higher 2-year DMFS increments were older at baseline and had higher salivary glucose concentrations than children with lower 2-year DMFS increments. Likewise, higher 2-year DMFS increments in diabetics versus controls were associated with greater increments in salivary glucose concentrations in diabetics. Higher increments in active caries lesions in diabetics versus controls were associated with greater increments of dental plaque and greater increments of salivary albumin. Our results suggest that, in addition to dental plaque as a common caries risk factor, diabetes-induced changes in salivary glucose and albumin concentrations are indicative of caries development among diabetics. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

This in situ/ex vivo study assessed the effect of different concentrations of fluoride in dentifrices on dentin subjected to erosion or to erosion plus abrasion. Ten volunteers took part in this crossover and double-blind study performed in 3 phases (7 days). They wore acrylic palatal appliances containing 4 bovine dentin blocks divided in two rows: erosion and erosion plus abrasion. The blocks were subjected to erosion by immersion ex vivo in a cola drink (60 s, pH 2.6) 4 times daily. During this step, the volunteers brushed their teeth with one of three dentifrices D (5,000 ppm F, NaF, silica); C (1,100 ppm F, NaF, silica) and placebo (22 ppm F, silica). Then, the respective dentifrice slurry (1:3) was dripped on dentin surfaces. While no further treatment was performed in one row, the other row was brushed using an electric toothbrush for 30 s ex vivo. The appliances were replaced in the mouth and the volunteers rinsed with water. Dentin loss was determined by profilometry and analyzed by 2-way ANOVA/Bonferroni test (a = 0.05). Dentin loss after erosive-abrasive wear was significantly greater than after erosion alone. Wear was significantly higher for the placebo than for the D and C dentifrices, which were not significantly different from each other. It can be concluded that the presence of fluoride concentrations around 1,100 ppm in dentifrices is important to reduce dentin wear by erosion and erosion + abrasion, but the protective effect does not increase with fluoride concentration. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The infiltration of proximal enamel lesions with low-viscosity light curing resins could be a viable approach to stop lesion progression. However, penetration of sealant might be hampered by the comparatively highly mineralized surface layers of natural lesions. Therefore, the aim of this study was to compare the efficacy of three different etching gels in removing the surface layer in various etching times. Extracted human molars and premolars showing proximal white spot lesions were cut across the demineralized areas. Ninety-six lesions expected from visual examination to be confined to the outer enamel (C1) were selected. The cut surface and half of each lesion were varnished, thus serving as control. Subsequently, the lesions were etched with either phosphoric (37%) or hydrochloric (5 or 15%) acid gel for 30–120 s (n = 8/group). Specimens were examined using confocal microscopy and transversal microradiography. Surface layer reduction was significantly increased in lesions etched with 15% HCl gel for 90 and 120 s compared to those etched with H3PO4 gel for 30–120 s (p < 0.05). No significant differences regarding the depths of erosion in the lesions compared to sound enamel could be observed (p > 0.05). An effective reduction in the surface layer of natural enamel caries can be achieved by etching with 15% hydrochloric acid gel for 90–120 s. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

It has been suggested that laser fluorescence close to the dental pulp shows higher values than more distant measurements. The aim of this study was to assess fluorescence on the cavity floor and to correlate these measurements with electrical resistance as a measure of residual dentine thickness. Thirty carious lesions were excavated with a bur. The endpoint of caries removal was determined by visual, tactile and auditory means. Fluorescence was measured with the Diagnodent device and with the fluorescence feedback system of a therapeutic Er:YAG laser. Electrical resistance of the residual dentine (Prepometer units, PU) was measured with a proprietary device. Significant differences were observed between the fluorescence systems (p < 0.05). For Diagnodent, a decrease of electrical resistance of the residual dentine resulted in an increase of the fluorescence values of 2.99 units/PU (95% CI = 2.00–3.97) and an increase of 0.30 units/PU (95% CI = 0.19–0.40) for the fluorescence feedback system. For zero electrical resistance, a predicted maximum value of 51.5 units (95% CI = 41.3–61.7) was calculated for the Diagnodent and 5.1 units (95% CI = 4.1–6.2) for the feedback system. The study indicates that using the suggested detection cut-off with the Diagnodent device may be not suited to assess the endpoint of caries removal close to the dental pulp. Employing the Key Laser III, values up to 6 units might be caused solely by close proximity to the pulp, which should be considered when caries removal by laser is controlled by laser fluorescence feedback. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

This study addressed the dose response between fluoride toothpastes and in vitro de- and remineralization, to predict the efficacy of toothpastes and understand the mode of action in the range 0–3,000 ppm F. Enamel lesions were pH-cycled with calcium uptake and loss being assessed daily. Both ‘shallow’ (about 50 μm deep) and ‘deep’ (about 200 μm deep) lesions were studied. F treatments were given in 30 (w/v)% toothpaste dilutions for up to 5 min daily. Calcium loss during the demineralization periods showed a dose response, resulting in 72% reduction for 3,000 ppm F compared to 0 ppm F. Calcium uptake during remineralization was increased in the F compared to non-F groups, with F concentration being less important than its mere presence. Significant differences were observed in F response between shallow and deep lesions, suggesting that this parameter should be included when testing caries-preventive products. Microradiographic analysis showed that lesion depth and severity had increased significantly in the non-F groups. In the F groups, the original lesion was partly remineralized, while a new lesion had formed beyond the original lesion front. Mineral loss of this second lesion correlated inversely with the F concentration of the treatments. These data revealed that fluoride can drive demineralization further into enamel by making the surface tissue less soluble, hence by not neutralizing acids penetrating into the tissue. It is also concluded that depth analysis of mineral uptake and loss is important to understand the mode of action of different F products. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aim: To establish a fluorescence threshold level that could guide a therapeutic Er:YAG laser through a caries lesion to determine a therapeutic endpoint of caries removal. Materials and Methods: A total of 65 extracted human teeth, 35 with dentine caries and 30 healthy, were used for this study. An Er:YAG laser system that emitted at a wavelength of 2.94 μm was used. The laser was equipped with a laser fluorescence feedback system, excitation wavelength 655 nm, to control the irradiation by the Er:YAG laser. The evaluated threshold levels of the fluorescence feedback system were 3, 7, 8, 10, 12, 15 and 20. After treatment the teeth were prepared for histological staining according to the method of Brown and Brenn for the identification of bacteria. The specimens were subjected to a quantitative evaluation of residual bacteria on the treated dentine surface. In addition, the internal fluorescence of dentine and potential fluorescence changes of dentine after laser irradiation were evaluated. Results: About 80% of the irradiated dentine surface showed residual bacteria with threshold levels of 20, 15, 12, and 10. Residual bacteria were not found with threshold levels of 7 and 3. The study revealed a significant increase in dentine fluorescence after laser irradiation. Conclusion: The results of the present in vitro study indicate that a fluorescence threshold level of 7 or 8 units can guide an Er:YAG laser to a complete removal of carious dentine. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aim was to study remineralization in dentin underneath a biofilm. This was done in a constant depth film fermentor (CDFF) which was modified so that two treatments can be applied simultaneously in one experiment. Forty-five Streptococcus mutans biofilms were grown in grooves in dentin. Growth medium (3.7 g/l BHI, 1.5 mM calcium and 25 mM PIPES) was administered alternately with 2% sucrose pulsing 4 × 30 min/day. Fluoride at 135 ppm as NaF only or in a mixture with 0.2% chlorhexidine was applied for 2 × 5 min/day. The treatments started 5 days after inoculation and lasted 15 days. Five specimens per group were removed at various time points. The biofilms were checked for viability (by plating) and acid content (by capillary electrophoresis). The dentin specimens were analysed for mineral loss and lesion depth (by transversal microradiography). Fluoride treatment had no effect on the viability but reduced lactic acid production by 75%. The mixture treatment reduced the viability by 80% and the lactic acid content by 93% on the first day and later reduced the two parameters to below the detection limits. Significant differences in changes in mineral loss and lesion depth were observed between the treatment groups. Partial remineralization but deeper lesions were observed in the fluoride group, while nearly complete remineralization was seen in the mixture group. In conclusion, the CDFF S. mutans biofilm model can be used as a de- and remineralization biofilm model, and the split mode is particularly suitable for testing caries-preventive agents. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aim of this study was to compare emission spectra from noncavitated enamel caries with different degrees of discoloration under a wide range of excitation wavelengths. Freshly extracted human molars with white spot, light discolored and dark discolored brown spot enamel caries were selected (n = 4 each). Rectangular blocks (3.5 × 3.5 mm) were cut from the carious area and a corresponding sound area of the same tooth. Emission spectra were recorded from carious and the corresponding sound areas using a fluorescence spectrophotometer at excitation wavelengths from 360 nm up to 580 nm in steps of 20 nm. The specimens were submerged in water during measurement. The spectra were corrected and normalized to peak intensity for comparisons between spectra from sound and carious areas of each tooth. Excitation spectra were recorded for selected emission wavelengths that showed maximum intensity. Emission spectra of all types of carious lesions were shifted towards longer wavelengths (red shift) when compared to the spectra of the corresponding sound enamel. The red shift was highest for dark brown spot lesions and lowest for white spot lesions (p ≤ 0.001). Distinct fluorescence bands within 600–700 nm typical for porphyrin compounds were strongest for excitation wavelengths from 400 to 420 nm and present in most of the lesions investigated. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the relationship between electrical resistance (ECM) measurements and microradiographic variables during remineralization of softened enamel lesions. Sound bovine enamel blocks were demineralized and, subsequently, were remineralized for 3, 4, 5, 7 or 14 days. All the specimens were assessed by ECM and transversal microradiography. The mean ECM values in each group increased after remineralization. The ECM values after remineralization (ECM1), mineral loss (ΔZ) and maximum mineral content in the surface layer (Vmax) were significantly correlated with the remineralization time. The ECM1 values were also significantly correlated with ΔZ and Vmax. It is suggested that ECM could be used as a device to monitor mineral accumulation as a result of preventive treatment in vitro. However, it may take a much longer time to follow up the remineralization changes compared with demineralization. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of saliva composition on caries lesion development independently of the flow rate of unstimulated whole saliva (UWS) and other caries-related variables such as lesion progression time, oral hygiene level, and fluoride exposure. We hypothesized that this could be done by developing experimental root caries under carefully controlled conditions in situ in test subjects with UWS flow rates within a narrow window of normalcy. Fifteen female and 5 male subjects (66 ± 6 years) were selected for the study according to their UWS flow rates between 0.2 and 0.4 ml/min. All subjects developed experimental root caries lesions during a 62-day period in which UWS as well as stimulated whole saliva (SWS) were repeatedly collected and analysed for flow rate, pH, buffer capacity, inorganic, and organic composition. Caries lesion development was determined by quantitative microradiography. The mean UWS flow rate was 0.30 ± 0.05 ml/min. Significant negative correlations were obtained between UWS total phosphate concentration and mineral loss (ΔZ; rs = –0.72, p < 0.001) and UWS total protein concentration and ΔZ (rs = –0.70, p < 0.01). SWS and its constituents had only limited or no effect on ΔZ. Qualitative UWS protein analysis (SDS-PAGE) revealed that subjects with low ΔZ values had broader and more stained amylase bands than subjects with high ΔZ values. These findings were confirmed quantitatively by HPLC. We conclude that, within a group of subjects with normal UWS flow rates, the UWS composition was more important for caries lesion development than the SWS composition. Furthermore, high UWS concentrations of phosphate, protein, and amylase were caries-protective. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Non-intrusive, non-contacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with 659- and 830-nm laser sources to assess the pits and fissures on the occlusal surfaces of human teeth. Fifty-two human teeth were examined with simultaneous measurements of PTR and LUM and were compared to conventional diagnostic methods including continuous (dc) luminescence (DIAGNOdent), visual inspection and radiographs. To compare each method to the others, sensitivities and specificities were calculated by using histological observations as the gold standard. With the combined criteria of four PTR and LUM signals (two amplitudes and two phases), it was found that the sensitivity of this method was much higher than any of the other methods used in this study, whereas the specificity was comparable to that of dc luminescence diagnostics. Therefore, PTR and LUM, as a combined technique, has the potential to be a reliable tool to diagnose early pit and fissure caries and could provide detailed information about deep lesions. Using the longer wavelength (830-nm) laser source, it has been shown that detection of deeper subsurface lesions than the 659-nm probe provides is possible. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the effects of fluoride on erosive mineral loss in human enamel and dentine using a cyclic de- and remineralisation model in situ. The study was a three-treatment (5 days each) crossover design involving 4 (enamel) or 6 (dentine) healthy volunteers. Samples were recessed in palatal mouth appliances and worn day and night except during meals and were demineralised extraorally with 0.05 M citric acid (pH 2.3) for 6 x 5 min daily. Fluoridation was performed with toothpaste (SnF2/Olaflur; 0.14% F-) for 3 x 5 min daily (toothpaste fluoridation) or with toothpaste in combination with a mouthrinse (SnF2/Olaflur; 0.025% F-) for 3 x 5 min daily and with a gel (NaF/Olaflur, 1.25% F-) on days 1 and 3 instead of the toothpaste (intensive fluoridation). In the control group no fluoridation was performed. Mineral loss (microm) was determined with the use of longitudinal microradiography. In enamel, mineral loss was 40.7 +/- 15.1 microm in the control group, 18.3 +/- 12.4 microm after toothpaste fluoridation and 5.0 +/- 12.2 microm after intensive fluoridation. The respective values for dentine were 49.0 +/- 15.4, 35.0 +/- 15.5 and 19.8 +/- 12.0 microm. All differences were statistically significant (p < or = 0.001). The results indicate that intensive fluoridation is effective in preventing enamel and dentine from mineral loss even under severely erosive conditions. [ABSTRACT FROM AUTHOR]

Drying effects in 14 natural lesions were studied with quantitative light-induced fluorescence and optical pathl-ength spectroscopy. Results were compared with clinical judgments of the lesion surface and microradiographical characterizations of the lesions. Relative fluorescence and average pathlength decreased as a function of drying time with a decay time ranging from 35.5 to <1 min. Depth and mineral loss correlated with average pathlength total changes (r = -0.79/-0.60, respectively) and poorly with total fluorescence changes (r ≅ 0.3). The decay time of the drying process for the relative fluorescence correlated well with a theoretical model based on water diffusion in lesion and surface layer, but only for large decay times. Clinical judgments could not be related to the surface layer properties or the changes in the average pathlength, but were weakly related to the changes in the relative fluorescence. We conclude that (i) fluorescence effects are mostly due to the screening by the lesion of the fluorescence from the dentin and enamel- dentin junction; (ii) water evaporation in lesions conforms to the diffusion laws only in large lesions with low surface layer penetrability; (iii) the evaporation process is controlled by the surface layer only for small surface penetrabilities (≈ 0.1 vol% µm-1). [ABSTRACT FROM AUTHOR]

The diode laser fluorescence device was introduced to diagnose caries lesions in occlusal and smooth surfaces. Despite promising results, much variation has been found in the protocol of utilization. The goal of this study was to evaluate the influence of dental plaque and drying time on the laser fluorescence (DIAGNOdent) performance in occlusal sites of primary molars. For the drying time study, 63 suspected occlusal sites in primary molars were used. The same sites were evaluated in four different conditions: (1) moist teeth, (2) teeth dried for 3 s with a 3-in-1 syringe, (3) teeth dried for 15 s, and (4) dehydrated teeth. For the plaque experiment, we selected 28 occlusal sites. After the baseline laser fluorescence readings, plaque collected from children was placed on the suspected site. New laser fluorescence measurements were performed. For both studies, we compared the laser fluorescence values, as well as sensitivity, specificity, accuracy, and area under ROC curve. For different drying times, the more dehydrated the teeth, the higher the values. Nevertheless, the performance of the method did not change significantly, except for dehydrated teeth. In the presence of plaque, the laser fluorescence values were reduced, and the evaluated parameters were worse than with no plaque. In conclusion, the hydration state of the teeth did not change the results significantly, but the presence of plaque worsened the performance of the laser fluorescence method. [ABSTRACT FROM AUTHOR]

Since the use of bovine instead of human dentine to evaluate cariogenic and anticariogenic substances is not well established, this in situ study was conducted. Eleven volunteers wore palatal acrylic devices containing 4 dentine slabs (2 human and 2 bovine). Sucrose solution (20%) was dripped over all slabs 4 times a day, simulating a cariogenic challenge. Dentifrice slurries, fluoridated or not, were dripped over specified dentine slabs 3 times a day to evaluate caries reduction. After 14 days, the biofilm formed on the dentine slabs was collected for microbiological analysis. In dentine, mineral loss (ΔZ) and lesion depth (LD) were determined by cross-sectional microhardness and by polarized light microscopy, respectively. The total streptococci and mutans streptococci counts in the biofilm formed either on human or on bovine slabs, whether treated or not with fluoride dentifrice, were not statistically different. The ΔZ and the LD values of dentine treated with fluoride dentifrice were significantly lower than the values of dentine treated with non-fluoride dentifrice. The differences in the ΔZ and LD values between the human and bovine dentine were not statistically significant. The results suggest that bovine dentine can be used instead of human to evaluate caries development and inhibition.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the effect of unstimulated saliva flow rate on experimental root caries lesion characteristics. These characteristics include mineral loss, lesion depth and mineral distribution in experimental root caries lesions in situ. It showed that all demineralization parameters were correlated with the unstimulated saliva flow rate. Multiple regression analyses showed that the unstimulated saliva flow rate alone explained the variance in the demineralization parameters.

AbstractDentine root caries is a process of demineralization and degradation of the organic matrix by proteinases. In this in situ study, the presence and activity of the matrix metalloproteinases 1, 2 and 9 (MMP-1, MMP-2, MMP-9) in saliva and in completely demineralized dentine specimens were investigated. Furthermore, the activity of cathepsin B was determined in saliva. A correlation between these enzymes and the level of degraded collagen was investigated. Demineralized dentine specimens were mounted in the partial prosthesis of 17 volunteers. Saliva samples were taken at 0, 2 and 4 weeks. After 4 weeks, the enzymes were extracted from the dentine specimens and the collagen loss was assessed. The collagen loss varied between 0 and 40.3%. Zymography of the saliva and the dentine extract samples showed that (pro-)MMP-2 and (pro-)MMP-9 were present. The levels of active MMPs were assessed, using fluorogenic MMP-specific substrates. All but 3 of the 51 saliva samples showed MMP-1 activity ranging from 1.5 to 101.1 relative fluorescence units (RFU)/s. Forty-eight saliva samples showed gelatinolytic MMP-2/MMP-9 activity (1.7–141.1 RFU/s). MMP-1 activity was shown in all dentine extracts varying between 3.5 and 295.0 RFU/s. From the dentine extracts, 15 showed MMP-2/MMP-9 activity (0.2–13.7 RFU/s). The MMP activity from both saliva and dentine extracts did not correlate with the collagen loss. The activity of salivary cathepsin B varied from 4.8 to 42.2 arbitrary units/min. A positive correlation was found between salivary MMP activity and cathepsin B activity. This study revealed that gelatinolytic enzyme activity was present both in saliva and dentine collagen. No correlation could be observed, however, between the level of enzyme activity and the collagen loss of the dentine specimens.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]