Longevity of dental restorations in Sjogren's disease patients using electronic dental and health record data.

BACKGROUND: Decreased salivary secretion is not only a risk factor for carious lesions in Sjögren's disease (SD) but also an indicator of deterioration of teeth with every restorative replacement. This study determined the longevity of direct dental restorations placed in patients with SD using matched electronic dental record (EDR) and electronic health record (EHR) data. METHODS: We conducted a retrospective cohort study using EDR and EHR data of Indiana University School of Dentistry patients who have a SD diagnosis in their EHR. Treatment history of patients during 15 years with SD (cases) and their matched controls with at least one direct dental restoration were retrieved from the EDR. Descriptive statistics summarized the study population characteristics. Cox regression models with random effects analyzed differences between cases and controls for time to direct restoration failure. Further the model explored the effect of covariates such as age, sex, race, dental insurance, medical insurance, medical diagnosis, medication use, preventive dental visits per year, and the number of tooth surfaces on time to restoration failure. RESULTS: At least one completed direct restoration was present for 102 cases and 42 controls resulting in a cohort of 144 patients' EDR and EHR data. The cases were distributed as 21 positives, 57 negatives, and 24 uncertain cases based on clinical findings. The average age was 56, about 93% were females, 54% were White, 74% had no dental insurance, 61% had public medical insurance, < 1 preventive dental visit per year, 94% used medications and 93% had a medical diagnosis that potentially causes dry mouth within the overall study cohort. About 529 direct dental restorations were present in cases with SD and 140 restorations in corresponding controls. Hazard ratios of 2.99 (1.48-6.03; p = 0.002) and 3.30 (1.49-7.31, p-value: 0.003) showed significantly decreased time to restoration failure among cases and positive for SD cases compared to controls, respectively. Except for the number of tooth surfaces, no other covariates had a significant influence on the survival time. CONCLUSION: Considering the rapid failure of dental restorations, appropriate post-treatment assessment, management, and evaluation should be implemented while planning restorative dental procedures among cases with SD. Since survival time is decreased with an increase in the number of surfaces, guidelines for restorative procedures should be formulated specifically for patients with SD.

Iron oxide nanozymes stabilize stannous fluoride for targeted biofilm killing and synergistic oral disease prevention.

Dental caries is the most common human disease caused by oral biofilms despite the widespread use of fluoride as the primary anticaries agent. Recently, an FDA-approved iron oxide nanoparticle (ferumoxytol, Fer) has shown to kill and degrade caries-causing biofilms through catalytic activation of hydrogen peroxide. However, Fer cannot interfere with enamel acid demineralization. Here, we show notable synergy when Fer is combined with stannous fluoride (SnF2), markedly inhibiting both biofilm accumulation and enamel damage more effectively than either alone. Unexpectedly, we discover that the stability of SnF2 is enhanced when mixed with Fer in aqueous solutions while increasing catalytic activity of Fer without any additives. Notably, Fer in combination with SnF2 is exceptionally effective in controlling dental caries in vivo, even at four times lower concentrations, without adverse effects on host tissues or oral microbiome. Our results reveal a potent therapeutic synergism using approved agents while providing facile SnF2 stabilization, to prevent a widespread oral disease with reduced fluoride exposure.

Exploratory Analysis of Objective Outcome Measures for the Clinical Assessment of Erosive Tooth Wear.

This study proposed using enamel surface texture and thickness for the objective detection and monitoring of erosive tooth wear (ETW), comparing them to the standard subjective Basic Erosive Wear Evaluation (BEWE). Thirty-two subjects (n = 597 teeth) were enrolled in this longitudinal observational clinical study. Enamel thickness (by cross-polarization optical coherence tomography, CP-OCT) and 3D dental microwear parameters, i.e., area-scale fractal complexity (Asfc), anisotropy (Str), and roughness (Sa) (by white-light scanning confocal profilometry), were obtained from buccal surfaces. Buccal, occlusal, and lingual surfaces were scored for BEWE and the maximum score per tooth (BEWEMax) was determined at baseline and 12 months (M12). Data outcome relationships were evaluated (alpha = 0.05). Enamel thickness decreased (p < 0.001), BEWE scores, Sa, and Str increased (p < 0.001), while Asfc did not change at M12. Baseline BEWEBuccal correlated strongly with BEWEMax (r = 0.86, p < 0.001) and moderately with BEWELingual (r = 0.42, p < 0.001), but not with enamel thickness (r = 0.03, p = 0.43). Change (Δ) in surface texture outcomes correlated poorly but significantly with ΔBEWEBuccal (r = -0.15-0.16, p < 0.001) and did not correlate with Δenamel thickness (r = 0.02-0.09, p > 0.06). Teeth with BEWE progression revealed a greater increase in ΔSa and ΔStr. These findings suggest that enamel surface roughness can potentially determine ETW severity, and CP-OCT may be relevant for clinically monitoring enamel thickness.

Characterizing clinical findings of Sjögren's Disease patients in community practices using matched electronic dental-health record data.

Established classifications exist to confirm Sjögren's Disease (SD) (previously referred as Sjögren's Syndrome) and recruit patients for research. However, no established classification exists for diagnosis in clinical settings causing delayed diagnosis. SD patients experience a huge dental disease burden impairing their quality of life. This study established criteria to characterize Indiana University School of Dentistry (IUSD) patients' SD based on symptoms and signs in the electronic health record (EHR) data available through the state-wide Indiana health information exchange (IHIE). Association between SD diagnosis, and comorbidities including other autoimmune conditions, and documentation of SD diagnosis in electronic dental record (EDR) were also determined. The IUSD patients' EDR were linked with their EHR data in the IHIE and queried for SD diagnostic ICD9/10 codes. The resulting cohorts' EHR clinical findings were characterized and classified using diagnostic criteria based on clinical experts' recommendations. Descriptive statistics were performed, and Chi-square tests determined the association between the different SD presentations and comorbidities including other autoimmune conditions. Eighty-three percent of IUSD patients had an EHR of which 377 patients had a SD diagnosis. They were characterized as positive (24%), uncertain (20%) and negative (56%) based on EHR clinical findings. Dry eyes and mouth were reported for 51% and positive Anti-Ro/SSA antibodies and anti-nuclear antibody (ANA) for 17% of this study cohort. One comorbidity was present in 98% and other autoimmune condition/s were present in 53% respectively. Significant differences were observed between the three SD clinical characteristics/classifications and certain medical and autoimmune conditions (p<0.05). Sixty-nine percent of patients' EDR did not mention SD, highlighting the huge gap in reporting SD during dental care. This study of SD patients diagnosed in community practices characterized three different SD clinical presentations, which can be used to generate SD study cohorts for longitudinal studies using EHR data. The results emphasize the heterogenous SD clinical presentations and the need for further research to diagnose SD early in community practice settings where most people seek care.

Evidence-based clinical practice guideline on restorative treatments for caries lesions: A report from the American Dental Association.

BACKGROUND: An expert panel convened by the American Dental Association (ADA) Council on Scientific Affairs together with the ADA Science and Research Institute's program for Clinical and Translational Research conducted a systematic review and developed recommendations for the treatment of moderate and advanced cavitated caries lesions in patients with vital, nonendodontically treated primary and permanent teeth. TYPES OF STUDIES REVIEWED: The authors searched for systematic reviews comparing carious tissue removal (CTR) approaches in Ovid MEDLINE, Embase, Cochrane Database of Systematic Reviews, and Trip Medical Database. The authors also conducted a systematic search for randomized controlled trials comparing direct restorative materials in Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. The authors used the Grading of Recommendations Assessment, Development, and Evaluation approach to assess the certainty of the evidence and formulate recommendations. RESULTS: The panel formulated 16 recommendations and good practice statements: 4 on CTR approaches specific to lesion depth and 12 on direct restorative materials specific to tooth location and surfaces involved. The panel conditionally recommended for the use of conservative CTR approaches, especially for advanced lesions. Although the panel conditionally recommended for the use of all direct restorative materials, they prioritized some materials over the use of others for certain clinical scenarios. PRACTICAL IMPLICATIONS: The evidence suggests that more conservative CTR approaches may decrease the risk of adverse effects. All included direct restorative materials may be effective in treating moderate and advanced caries lesions on vital, nonendodontically treated primary and permanent teeth.

Direct materials for restoring caries lesions: Systematic review and meta-analysis-a report of the American Dental Association Council on Scientific Affairs.

BACKGROUND: The goal of restoring caries lesions is to protect the pulp, prevent progression of the disease process, and restore the form and function of the tooth. The purpose of this systematic review was to determine the effect of different direct restorative materials for treating cavitated caries lesions on anterior and posterior primary and permanent teeth. TYPE OF STUDIES REVIEWED: The authors included parallel and split-mouth randomized controlled trials comparing the effectiveness of direct restorative materials commercially available in the United States placed in vital, nonendodontically treated primary and permanent teeth. Pairs of reviewers independently conducted study selection, data extraction, and assessments of risk of bias and certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. The authors conducted pair-wise meta-analyses to summarize the evidence and calculated measures of association and their 95% CIs. RESULTS: Thirty-eight randomized controlled trials were eligible for analysis, which included data on Class I and Class II restorations on primary teeth and Class I, Class II, Class III, Class V, and root surface restorations on permanent teeth. Included studies assessed the effect of amalgam, resin composite, compomer, conventional glass ionomer cement, resin-modified glass isomer cement, and preformed metal crowns. Moderate to very low certainty evidence suggested varying levels of effectiveness across restorative materials. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Owing to a relatively low event rate across various outcomes indicating restoration failure, there was limited evidence to support important differences between direct restorative materials used in practice.

Effect of phenylmethylsulfonyl fluoride, a protease inhibitor, on enamel surface remineralization

Phenylmethylsulfonyl fluoride (PMSF) is a protease inhibitor widely used in research, but fluoride is released during its action and this knowledge has been neglected in dental research. Aim: to evaluate if fluoride released by salivary protease action on PMSF affects enamel remineralization and fluoride uptake. Methods: Groups of 10 enamel slabs, with caries-like lesions and known surface hardness (SH), were subjected to one of the following treatment groups: Stimulated human saliva (SHS), negative control; SHS containing 1.0 µg F/mL (NaF), positive control; and SHS containing 10, 50 or 100 µM PMSF. The slabs were subjected to a pH-cycling regimen consisting of 22 h/day in each treatment solution and 2 h/day in a demineralizing solution. After 12 days, SH was again measured to calculate the percentage of surface hardness recovery (%SHR), followed by enamel fluoride uptake determination. The time-related fluoride release from 100.0 µM PMSF by SHS action was also determined. Data were analyzed by ANOVA followed by Newman-Keuls test. Results: The release of fluoride from PMSF by SHS was rapid, reaching a maximum value after 10 min. Fluoride released from PMSF was more effective in enhancing %SHR and increasing fluoride uptake in enamel compared with SHS alone (p < 0.05); furthermore, it was equivalent to the positive control (p > 0.05). Conclusion: In conclusion, fluoride released by saliva from PMSF is available to react with enamel and needs to be taken into account in research using this protease inhibitor

Ferumoxytol Nanoparticles Target Biofilms Causing Tooth Decay in the Human Mouth.

Severe tooth decay has been associated with iron deficiency anemia that disproportionally burdens susceptible populations. Current modalities are insufficient in severe cases where pathogenic dental biofilms rapidly accumulate, requiring new antibiofilm approaches. Here, we show that ferumoxytol, a Food and Drug Administration-approved nanoparticle formulation for treating iron deficiency, exerts an alternative therapeutic activity via the catalytic activation of hydrogen peroxide, which targets bacterial pathogens in biofilms and suppresses tooth enamel decay in an intraoral human disease model. Data reveal the potent antimicrobial specificity of ferumoxytol iron oxide nanoparticles (FerIONP) against biofilms harboring Streptococcus mutans via preferential binding that promotes bacterial killing through in situ free-radical generation. Further analysis indicates that the targeting mechanism involves interactions of FerIONP with pathogen-specific glucan-binding proteins, which have a minimal effect on commensal streptococci. In addition, we demonstrate that FerIONP can detect pathogenic biofilms on natural teeth via a facile colorimetric reaction. Our findings provide clinical evidence and the theranostic potential of catalytic nanoparticles as a targeted anti-infective nanomedicine.

Cross-polarization optical coherence tomographic assessment of in situ simulated erosive tooth wear.

This clinical study tested cross-polarization optical coherence tomography (CP-OCT) monitoring of erosive tooth wear (ETW). Twenty participants completed a 14-day/arm, 3-arm crossover study simulating different ETW severities. Participants received two enamel specimens (per arm) and were randomized to: severe (s-ETW, lemon juice/pH:2.5/4.25%wt/vol citric acid), moderate (m-ETW, grapefruit juice/pH:3.5/1.03%wt/vol citric acid), and non-ETW (water). Enamel thickness was measured with CP-OCT (day[D] 0, 7, 14) and micro-computed tomography (µ-CT; D14). Enamel surface loss was determined with CP-OCT and optical profilometry (OP; D7, D14). CP-OCT showed higher enamel surface loss for D14 than D7 for m-ETW (P = .009) and s-ETW (P = .040) and differentiated severity at D14 (s-ETW > non-ETW, P = .027). OP was able to differentiate surface loss between days (D7 < D14, P < .001) for m-ETW and s-ETW, and ETW severity effect after 7 and 14 days (non-ETW < m-ETW < s-ETW, P < .001). At D14, CP-OCT and µ-CT were positively correlated (r = .87, ICC = .62). CP-OCT showed potential as a tool for clinical ETW monitoring.

How to Intervene in the Caries Process in Children: A Joint ORCA and EFCD Expert Delphi Consensus Statement.

This paper provides recommendations for dentists for the treatment of dental caries in children, with an emphasis on early childhood caries (ECC), primary teeth, and occlusal surfaces in permanent teeth. A consensus workshop followed by an e-Delphi consensus process was conducted with an expert panel nominated by the European Organization for Caries Research (ORCA) and European Federation of Conservative Dentistry (EFCD)/German Association of Conservative Dentistry (DGZ) boards. Based on 3 systematic reviews and a nonsystematic literature search, recommendations were developed. The caries decline has led to a more polarized disease distribution in children and adolescents along social gradients which should be taken into account when managing the caries process at all levels, such as the individual, the group, or a population. The control or reduction of caries activity is the basis for successful caries management. In children, caries management requires adequate daily oral hygiene and fluoride application via toothpaste, ensured by caregivers, and especially for ECC prevention an emphasis on sugar intake reduction is needed. These noninvasive interventions are also suitable to arrest or control initial or even cavitated dentine caries lesions in the absence of irreversible pulpitis. Fluoride varnish or silver diammine fluoride can be added as supplementary agents. In pits and fissures, composite resin materials can be used as preventive sealants and for defect-oriented minimally invasive restorations. In primary molars, preformed metal crowns are more successful than multisurface fillings, especially in caries-active patients. With persisting high caries activity, multiple lesions, and limited cooperation, caries control should consist of robust measures with high success rates, even including extraction in selected cases. This applies especially to treatments performed under general anesthesia.

In situ efficacy of an experimental toothpaste on enamel rehardening and prevention of demineralisation: a randomised, controlled trial.

BACKGROUND: A novel sodium fluoride toothpaste containing lactate ion and polyvinylmethylether-maleic anhydride has been developed to promote enamel remineralisation and resistance to demineralisation. In this in situ study, we compared this toothpaste ('Test') with a stannous fluoride-zinc citrate (SnF2-Zn) toothpaste ('Reference') (both 1100-1150 ppm fluoride) and a fluoride-free toothpaste ('Placebo') using an enamel dental erosion-rehardening model. METHODS: In each phase of this randomised, investigator-blind, crossover study, participants wore palatal appliances holding bovine enamel specimens with erosive lesions. They brushed their natural teeth with either the Test, Reference or Placebo toothpastes, then swished the resultant slurry. Specimens were removed at 2 h and 4 h post-brushing and exposed to an in vitro acid challenge. Surface microhardness was measured at each stage; enamel fluoride uptake was measured after in situ rehardening. Surface microhardness recovery, relative erosion resistance, enamel fluoride uptake and acid resistance ratio were calculated at both timepoints. RESULTS: Sixty two randomised participants completed the study. Test toothpaste treatment yielded significantly greater surface microhardness recovery, relative erosion resistance and enamel fluoride uptake values than either Reference or Placebo toothpastes after 2 and 4 h. The acid resistance ratio value for Test toothpaste was significantly greater than either of the other treatments after 2 h; after 4 h, it was significantly greater versus Placebo only. No treatment-related adverse events were reported. CONCLUSIONS: In this in situ model, the novel-formulation sodium fluoride toothpaste enhanced enamel rehardening and overall protection against demineralisation compared with a fluoride-free toothpaste and a marketed SnF2-Zn toothpaste. TRIAL REGISTRATION: ClinicalTrials.gov; NCT03296072; registered September 28, 2017.

European Organization for Caries Research Workshop: Methodology for Determination of Potentially Available Fluoride in Toothpastes.

Toothpastes are the most universally accepted form of fluoride delivery for caries prevention. To provide anti-caries benefits, they must be able to release fluoride during the time of tooth brushing or post brushing into the oral cavity. However, there is no standard accepted procedure to measure how much fluoride in a toothpaste may be (bio) available for release. The European Organization for Caries Research proposed and supported a workshop with experts in fluoride analysis in toothpastes and representatives from industry. The objective of the workshop was to discuss issues surrounding fluoride analysis in toothpaste and reach consensus on terminology and best practices, wherever the available evidence allowed it. Participants received a background paper and heard presentations followed by structured discussion to define the problem. The group also reviewed evidence on the validity, reliability and feasibility of each technique (namely chromatography and fluoride electroanalysis) and discussed their strengths and limitations. Participants were able to reach a consensus on terminology and were also able to identify and summarize the advantages and disadvantages of each technique. However, they agreed that most currently available methods were developed for regulatory agencies several decades ago, utilizing the best available data from clinical trials then, but require to be updated. They also agreed that although significant advances to our understanding of the mechanism of action of fluoride in toothpaste have been achieved over the past 4 decades, this clearly is an extraordinarily complex subject and more work remains to be done.

Evidence-based clinical practice guideline on nonrestorative treatments for carious lesions: A report from the American Dental Association.

BACKGROUND: An expert panel convened by the American Dental Association Council on Scientific Affairs and the Center for Evidence-Based Dentistry conducted a systematic review and formulated evidence-based clinical recommendations for the arrest or reversal of noncavitated and cavitated dental caries using nonrestorative treatments in children and adults. TYPES OF STUDIES REVIEWED: The authors conducted a systematic search of the literature in MEDLINE and Embase via Ovid, Cochrane CENTRAL, and Cochrane database of systematic reviews to identify randomized controlled trials reporting on nonrestorative treatments for noncavitated and cavitated carious lesions. The authors used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the certainty in the evidence and move from the evidence to the decisions. RESULTS: The expert panel formulated 11 clinical recommendations, each specific to lesion type, tooth surface, and dentition. Of the most effective interventions, the panel provided recommendations for the use of 38% silver diamine fluoride, sealants, 5% sodium fluoride varnish, 1.23% acidulated phosphate fluoride gel, and 5,000 parts per million fluoride (1.1% sodium fluoride) toothpaste or gel, among others. The panel also provided a recommendation against the use of 10% casein phosphopeptide-amorphous calcium phosphate. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Although the recommended interventions are often used for caries prevention, or in conjunction with restorative treatment options, these approaches have shown to be effective in arresting or reversing carious lesions. Clinicians are encouraged to prioritize use of these interventions based on effectiveness, safety, and feasibility.

Objective and quantitative assessment of caries lesion activity.

OBJECTIVES: Evaluate the ability of objectively measured specular reflection, roughness, and fluorescence change during dehydration to assess caries lesion activity. METHODS: One hundred ninety-five ground/polished 3 × 3 × 2 mm sound human enamel specimens were divided into three groups and demineralized using a multispecies microbial caries model for 3, 6, or 9 days; and then remineralized with 1100 ppm-F as NaF solution for 10 days using a pH-cyclic model. Reflection (amplitude: %), roughness (Ra: µm), fluorescence change during dehydration (ΔQ: %×mm2), and microfocus computed tomography [µ-CT: lesion volume (µm3)] were measured for sound, demineralized and remineralized enamel. The surface was hydrated and fluorescence images were acquired at 1 s intervals for 10 s (ΔQ10). During image acquisition, surface was dehydrated with continuous compressed air. Changes-in-ΔQ per second (ΔQD: %×mm2/sec) at 5 (ΔQD5) and 10 s (ΔQD10) were obtained. RESULTS: Reflection decreased from sound to demineralized groups (p < 0.0001); remineralized groups were higher than demineralized groups (p < 0.001), but not different from sound (p > 0.32). Roughness increased from sound to demineralized groups (p < 0.0001) and remineralized groups were also higher than sound (p < 0.0001). ΔQ10, ΔQD5 and ΔQD10 increased from sound to demineralized groups (p < 0.0001), and remineralized groups decreased compared to demineralized groups (p < 0.05), but was higher than sound (p < 0.0001). The correlations of µ-CT with reflection, roughness, and ΔQ10 were -0.63, 0.71, and 0.82, respectively (p < 0.0001). CONCLUSIONS: Reflection, roughness and ΔQ could distinguish between sound and demineralized enamel. Reflection and ΔQ were able to distinguish between demineralized and remineralized enamel. CLINICAL SIGNIFICANCE: Determination of caries activity, whether a lesion is active or inactive, is an essential and critical component of caries diagnosis. However, especially for enamel lesions, it is difficult to estimate without longitudinal follow-up. Reflection, roughness and fluorescence change during dehydration have the potential to measure caries lesion activity at a-single-appointment.

In situ anticaries efficacy of dentifrices with different formulations - A pooled analysis of results from three randomized clinical trials.

OBJECTIVES: Data generated from three similar in situ caries crossover studies presented the opportunity to conduct a pooled analysis to investigate how dentifrice formulations with different fluoride salts and combinations at concentrations of 1400-1450 ppm F, different abrasive systems and in some cases, carbomer (Carb), affect enamel caries lesion remineralization and fluoridation. METHODS: Subjects continuously wore modified partial dentures holding two gauze-covered partially-demineralized human enamel specimens for 14 days and brushed 2×/day with their assigned dentifrice: Study 1: sodium fluoride (NaF)/Carb/silica, NaF/silica, NaF + monofluorophosphate (MFP)/chalk; Study 2: NaF/Carb/silica, NaF + MFP/dical, amine fluoride (AmF)/silica; Study 3: NaF/Carb/silica, NaF + stannous fluoride (SnF2)/silica/hexametaphosphate (HMP). All studies included Placebo (0 ppm F) and/or dose-response controls (675 ppm F as NaF [675F-NaF]) ±Carb. Specimens were evaluated for percentage surface microhardness recovery (SMHR) and enamel fluoride uptake (EFU). RESULTS: All 1400-1450 ppm F dentifrices except NaF + SnF2/silica/HMP provided significantly greater lesion remineralization than Placebo (p < 0.0001): differences in SMHR ranged from 17.46% (NaF + MFP/dical) to 26.66% (AmF/silica). For EFU (back-transformed log EFU), all 1400-1450 ppm F dentifrices gave significant fluoride uptake compared to Placebo (p < 0.0001): increases in EFU ranged from 4.95 µg F/cm2 (NaF + SnF2/silica/HMP) to 16.32 µg F/cm2 (NaF/carb/silica). Dentifrices containing NaF or AmF as sole fluoride source provided the greatest remineralization and fluoridation; Carb addition did not alter fluoride efficacy; some excipients appeared to interfere with the cariostatic action of fluoride. Treatments were generally well-tolerated with ≤4 treatment-related adverse events per study. CONCLUSION: Commercially available fluoride dentifrices varied greatly in their ability to remineralize and fluoridate early caries lesions. CLINICAL SIGNIFICANCE: Fluoride dentifrices are the most impactful anticaries modality worldwide. While clinical caries trials have not consistently shown the superiority of one formulation over another, these findings using a sensitive in situ caries model indicated that dentifrices containing NaF or AmF as the sole fluoride source provided the greatest remineralization and fluoridation benefits.

Impact of dentifrice abrasivity and remineralization time on erosive tooth wear in vitro.

PURPOSE: To investigate the in vitro effects of simulated dentifrice slurry abrasivity (L-low, M-medium and H-high) and remineralization time (0, 30, 60 and 120 minutes) on erosive tooth wear. METHODS: Enamel and root dentin specimens were prepared from bovine incisors (n= 8) and submitted to a cycling protocol including erosion, remineralization at the test times, and brushing with each of the tested slurries, for 5 days. Dental surface loss (SL) was determined by optical profilometry. Data was analyzed using mixed-model ANOVA and Fisher's PLSD tests (alpha= 0.05). RESULTS: SL generally increased along with the increase in slurry abrasive level, with significance dependent upon the specific substrate and remineralization times. H showed the highest SL on both enamel and dentin; remineralization for 30 minutes reduced SL significantly (P< 0.05), but only for enamel. M showed intermediate SL values, with remineralization benefit clearly seen only after 120 minutes of remineralization (P< 0.05). L caused the least SL for both enamel and dentin, which was further reduced after remineralization for 120 and 30 minutes, respectively (both P< 0.05). Overall, root dentin had significantly higher SL than enamel. Less abrasive dentifrice slurries were able to reduce toothbrushing abrasion on both enamel and root dentin. This protection was enhanced by remineralization for all abrasive levels on enamel, but only for L on root dentin. CLINICAL SIGNIFICANCE: High-risk erosion patients should avoid highly abrasive toothpastes, as remineralization can only partially compensate for their deleterious effects on eroded dental surfaces. Lower abrasive toothpastes are recommended.

Effect of phytate and zinc ions on fluoride toothpaste efficacy using an in situ caries model.

OBJECTIVES: To compare and explore the dose-response of phytate-containing 1150 ppm fluoride toothpastes on model caries lesions and to determine the impact of zinc ions. METHODS: This was a single-centre, randomised, blinded (examiner/laboratory analyst), six-treatment, four-period crossover, in situ study in adults with a removable bilateral maxillary partial denture. Study treatments were toothpastes containing: 0.425% phytate/F; 0.85% phytate/F; 0.85% phytate/Zn/F; F-only; Zn/F and a 0% F placebo. Where present, F was 1150 ppm as NaF; Zn was 0.3% as ZnCl2. Human enamel specimens containing early-stage, surface-softened (A-lesions) or more advanced, subsurface (B-lesions) caries lesions were placed into the buccal flanges of participants' modified partial denture (one of each lesion type per side). A-lesions were removed after 14 days of twice-daily treatment use; B-lesions were removed after a further 14 days. A-lesions were analysed for surface microhardness recovery. Both lesion types were analysed by transverse microradiography and for enamel fluoride uptake, with B-lesions additionally analysed by quantitative light-induced fluorescence. Comparison was carried out using an analysis of covariance model. RESULTS: Statistically significant differences between 1150 ppm F and the placebo toothpastes (p < 0.05) were shown for all measures, validating the model. No differences between fluoride toothpastes were observed for any measure with little evidence of a dose-response for phytate. Study treatments were generally well-tolerated. CONCLUSIONS: Results suggest phytate has little impact on fluoride's ability to promote early-stage lesion remineralisation or prevent more advanced lesion demineralisation in this in situ caries model. Similarly, results suggest zinc ions do not impair fluoride efficacy. CLINICAL SIGNIFICANCE: Toothpastes may contain therapeutic or cosmetic agents that could interfere with fluoride's caries prevention efficacy. The present in situ caries study has demonstrated that phytate, added to provide enhanced extrinsic stain removal/prevention, and zinc, added to inhibit malodour, do not impair fluoride efficacy.

Effects of a sodium fluoride- and phytate-containing dentifrice on remineralisation of enamel erosive lesions-an in situ randomised clinical study.

OBJECTIVE: The objective of this work was to evaluate effects of a dentifrice containing sodium fluoride (1150 ppm F) and the organic polyphosphate phytate (0.85% w/w of the hexa-sodium salt) on in situ remineralisation of early enamel erosive lesions and resistance to subsequent demineralisation. MATERIALS AND METHODS: Subjects (n = 62) wore palatal appliances holding eight bovine enamel specimens with pre-formed erosive lesions. They brushed their natural teeth with the phytate test dentifrice (TD); a positive control dentifrice (PC, 1150 ppm fluoride as NaF); a reference dentifrice (RD, disodium pyrophosphate + 1100 ppm fluoride as NaF) or a negative control dentifrice (NC, fluoride-free) in a randomised, double-blind, crossover design. Specimens were removed at 2, 4 and 8 h post-brushing and exposed to an ex vivo acid challenge. Surface microhardness (Knoop) was measured at each stage. The primary efficacy variable was relative erosion resistance (RER); other variables included the surface microhardness recovery (SMHR), acid resistance ratio (ARR) and enamel fluoride uptake (EFU). RESULTS: After 4 h, the results for RER, ARR and EFU were in the order PC > TD = RD > NC with PC > TD = RD = NC for SMHR. Results at 2 and 8 h were generally consistent with the 4 h data. Mineralisation progressed over time. Dentifrices were generally well-tolerated. CONCLUSIONS: In this in situ model, addition of phytate or pyrophosphate to a fluoride dentifrice inhibited the remineralising effect of fluoride. Both formulations still delivered fluoride to the enamel and inhibited demineralisation, albeit to a lesser extent than a polyphosphate-free dentifrice. CLINICAL RELEVANCE: Addition of phytate or pyrophosphate to a fluoride dentifrice may reduce its net anti-erosive properties.

A Randomized in situ Clinical Study of Fluoride Dentifrices on Enamel Remineralization and Resistance to Demineralization: Effects of Zinc.

This study aimed to determine the effect of zinc ions and F concentration in a dentifrice on remineralization of early caries lesions in situ and on resistance to subsequent demineralization. This was a single-center, 6-period, 6-product, blinded (examiner, subject, analyst), randomized (n = 62), crossover study. Products (all NaF) were: 0, 250, 1,150 and 1,426 ppm F (dose-response controls), "Zn-A" (0.3% ZnCl2, 1,426 ppm F), and "Zn-B" (as Zn-A, with high-foaming surfactants) in a conventional silica base. Subjects wore palatal appliances holding partially demineralized bovine enamel specimens. They brushed their teeth with 1.5 g test dentifrice (25 s), then swished the slurry ensuring even exposure of specimens (95 s), expectorated, and rinsed (15 mL water, 10 s). After 4 h intraoral remineralization, specimens were removed and acid-challenged in vitro. Surface microhardness (SMH), measured pre-experimental, post-initial acid exposure, post-remineralization, and post-second acid exposure, was used to calculate recovery (SMHR), net acid resistance (NAR), and a new, specifically demineralization-focused calculation, "comparative acid resistance" (CAR). Enamel fluoride uptake (EFU) was also measured. For the F dose-response controls, all measures showed significant relationships with dentifrice F concentration (p < 0.0001). The presence of zinc counteracted the ability of F to promote remineralization in this model. Compared to the 1,426 ppm F control, the zinc formulations gave reduced SMHR, EFU, and NAR (all p < 0.0001); however, they showed evidence of increased CAR (Zn-A: p = 0.0040; Zn-B: p = 0.0846). Products were generally well tolerated. In this study, increasing dentifrice F concentration progressively increased in situ remineralization and demineralization resistance of early caries enamel lesions. Zinc ions reduced remineralization but could increase demineralization resistance.