Should We Wait to Brush Our Teeth? A Scoping Review Regarding Dental Caries and Erosive Tooth Wear.

BACKGROUND: Tooth brushing is a universal recommendation. However, the recommendations related to the time of its execution are conflicting, especially when dealing with patients at risk of erosive tooth wear (ETW) or dental caries. SUMMARY: Our objective was to summarize the evidence on the timing of brushing with fluoridated toothpaste in relation to ETW and cariogenic dietary challenges. We conducted a scoping review following the PRISMA-ScR checklist, using three databases searching for in vivo, in situ, or in vitro studies involving human teeth exposed to either a cariogenic or an erosive challenge. Only models including human saliva and fluoride were assessed. Data selection, extraction, and risk of bias analysis were done in duplicate and independently. From 1,545 identified studies, 17 (16 related to ETW and 1 to dental caries) were included. Most evidence (n = 10) supported that brushing with a fluoride-containing product does not increase ETW, independent of the moment of brushing. Delaying tooth brushing up to 1 h (n = 4) or individualized recommendations based on the patient's problem (n = 2) were less frequent. Only one study reported that brushing pre- or post-meal does not affect Streptococcus mutans counts. Most data were in situ (n = 13), and the overall study quality was judged as sufficient/low risk of bias. KEY MESSAGES: Although the available evidence lacked robust clinical studies, tooth brushing using fluoridated products immediately after an erosive challenge does not increase the risk of ETW and can be recommended, which is in line with recommendations for dental caries prevention. Furthermore, we suggest updating the international guidelines to promote individualized recommendations based on risk factors to prevent either ETW or dental caries.

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.

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.

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

AIM: To provide recommendations for dental clinicians for the management of dental caries in older adults with special emphasis on root caries lesions. METHODS: A consensus workshop followed by a Delphi consensus process were conducted with an expert panel nominated by ORCA, EFCD, and DGZ boards. Based on a systematic review of the literature, as well as non-systematic literature search, recommendations for clinicians were developed and consented in a two-stage Delphi process. RESULTS: Demographic and epidemiologic changes will significantly increase the need of management of older adults and root caries in the future. Ageing is associated with a decline of intrinsic capacities and an increased risk of general diseases. As oral and systemic health are linked, bidirectional consequences of diseases and interventions need to be considered. Caries prevention and treatment in older adults must respond to the patient's individual abilities for self-care and cooperation and often involves the support of caregivers. Systemic interventions may involve dietary counselling, oral hygiene instruction, the use of fluoridated toothpastes, and the stimulation of salivary flow. Local interventions to manage root lesions may comprise local biofilm control, application of highly fluoridated toothpastes or varnishes as well as antimicrobial agents. Restorative treatment is often compromised by the accessibility of such root caries lesions as well as the ability of the senior patient to cooperate. If optimum restorative treatment is impossible or inappropriate, long-term stabilization, e.g., by using glass-ionomer cements, and palliative treatments that aim to maintain oral function as long and as well as possible may be the treatment of choice for the individual.

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.

Secondary caries: what is it, and how it can be controlled, detected, and managed?

OBJECTIVES: To assess how to control, detect, and treat secondary caries. This review serves to inform a joint ORCA/EFCD consensus process. METHODS: Systematic and non-systematic reviews were performed or consulted and narratively synthesized. RESULTS: Secondary (or recurrent) caries is defined as a lesion associated with restorations or sealants. While the restorative material itself has some influence on secondary caries, further factors like the presence and size of restoration gaps, patients' caries risk, and the placing dentist's experience seem more relevant. Current detection methods for secondary caries are only sparsely validated and likely prone for the risk of over-detection. In many patients, it might be prudent to prioritize specific detection methods to avoid invasive overtreatment. Detected secondary caries can be managed either by repair of the defective part of the restoration or its complete replacement. CONCLUSIONS: There is sparse data towards the nature of secondary caries and how to control, detect, and treat it. CLINICAL SIGNIFICANCE: Despite often claimed to be a major complication of restorations, there is surprisingly little data on secondary caries. Longer-term studies may be needed to identify differences in secondary caries risk between materials and to identify characteristic features of progressive lesions (i.e., those in need of treatment).

How to intervene in the caries process in adults: proximal and secondary caries? An EFCD-ORCA-DGZ expert Delphi consensus statement.

OBJECTIVES: To provide consensus recommendations on how to intervene in the caries process in adults, specifically proximal and secondary carious lesions. METHODS: Based on two systematic reviews, a consensus conference and followed by an e-Delphi consensus process were held with EFCD/ORCA/DGZ delegates. RESULTS: Managing an individual's caries risk using non-invasive means (oral hygiene measures including flossing/interdental brushes, fluoride application) is recommended, as both proximal and secondary carious lesions may be prevented or their activity reduced. For proximal lesions, only cavitated lesions (confirmed by visual-tactile, or radiographically extending into the middle/inner dentine third) should be treated invasively/restoratively. Non-cavitated lesions may be successfully arrested using non-invasive measures in low-risk individuals or if radiographically confined to the enamel. In high-risk individuals or if radiographically extended into dentine, for these lesions, additional micro-invasive (lesion sealing and infiltration) treatment should be considered. For restoring proximal lesions, adhesive direct restorations allow minimally invasive, tooth-preserving preparations. Amalgams come with a lower risk of secondary lesions and may be preferable in more clinically complex scenarios, dependent on specific national guidelines. In structurally compromised (especially endodontically treated) teeth, indirect cuspal coverage restorations may be indicated. Detection methods for secondary lesions should be tailored according to the individual's caries risk. Avoiding false positive detection and over-treatment is a priority. Bitewing radiographs should be combined with visual-tactile assessment to confirm secondary caries detections. Review/refurbishing/resealing/repairing instead of replacing partially defective restorations should be considered for managing secondary caries, if possible. CONCLUSIONS: An individualized and lesion-specific approach is recommended for intervening in the caries process in adults. CLINICAL SIGNIFICANCE: Dental clinicians have an increasing number of interventions available for the management of dental caries. Many of them are grounded in the growing understanding of the disease. The best evidence, patients' expectations, clinicians' expertise, and the individual clinical scenario all need to be considered during the decision-making process.

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.

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.

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.

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.

Anticaries Potential of a Sodium Monofluorophosphate Dentifrice Containing Calcium Sodium Phosphosilicate: Exploratory in situ Randomized Trial.

Calcium sodium phosphosilicate (CSPS) is a bioactive glass material that alleviates dentin hypersensitivity and is postulated to confer remineralization of caries lesions. This single-centre, randomized, single (investigator)-blind, placebo-controlled, crossover, in situ study explored whether the addition of 5% CSPS to a nonaqueous fluoride (F) such as sodium monofluorophosphate (SMFP)-containing dentifrice affects its cariostatic ability. Seventy-seven subjects wore 4 gauze-covered enamel specimens with preformed lesions (2 surface-softened and 2 subsurface) placed buccally on their mandibular bilateral dentures for up to 4 weeks. Subjects brushed twice daily with 1 of the 5 study dentifrices: 927 ppm F/5% CSPS, 927 ppm F/0% CSPS, 250 ppm F/0% CSPS, 0 ppm F/5% CSPS, or 0 ppm F/0% CSPS. Specimens were retrieved after either 21 (surface-softened lesions; analyzed by Knoop surface microhardness [SMH]) or 28 days (subsurface lesions; analyzed by transverse microradiography). The enamel fluoride uptake was determined for all specimens using a microbiopsy technique. The concentrations of fluoride and calcium in gauze-retrieved plaque were also evaluated. Higher dentifrice fluoride concentrations led to greater remineralization and fluoridation of both lesion types and increased plaque fluoride concentrations. CSPS did not improve the cariostatic properties of SMFP; there were no statistically significant differences between 927 ppm F/5% CSPS and 927 ppm F/0% CSPS in percent SMH recovery (p = 0.6788), change in integrated mineral loss (p = 0.5908), or lesion depth (p = 0.6622). Likewise, 0 ppm F/5% CSPS did not provide any benefits in comparison to 0 ppm F/0% CSPS. In conclusion, CSPS does not negatively impact nor does it improve the ability of an SMFP dentifrice to affect remineralization of caries lesions.

Erosion Remineralization Efficacy of Gel-to-Foam Fluoride Toothpastes in situ: A Randomized Clinical Trial.

This single-center, randomized, placebo-controlled, four-treatment, four-period crossover study compared the enamel remineralization effects of low- and medium-abrasivity gel-to-foam toothpastes and a reference toothpaste (all 1,450 ppm fluoride as NaF) versus placebo toothpaste (0 ppm fluoride) using a short-term in situ erosion model. Subjects (n = 56) wearing a palatal appliance holding acid-softened bovine enamel specimens brushed their teeth with the test toothpastes. Thereafter, the specimens were removed for analysis of percent surface microhardness recovery (%SMHR) and percent relative erosion resistance (%RER) at 2, 4, and 8 h. Both low- and medium-abrasivity gel-to-foam fluoride toothpastes and the reference toothpaste provided significantly greater %SMHR than placebo at all assessment time points (all p < 0.05). No statistically significant difference of %SMHR was observed between the fluoride treatment groups at any time point. Similarly, all fluoride products provided significantly superior %RER versus placebo (all p < 0.0001), whereas no significant difference of this parameter was noted between the fluoride treatment groups. Increasing numerical improvements of %SMHR and %RER were observed in all four treatment groups over time (2, 4, and 8 h). The present in situ model is a sensitive tool to investigate intrinsic and fluoride-enhanced rehardening of eroded enamel. All three fluoride toothpastes were more efficacious than placebo, and there were no safety concerns following single dosing in this short-term in situ model.

In vitro Detection of Occlusal Caries on Permanent Teeth by a Visual, Light-Induced Fluorescence and Photothermal Radiometry and Modulated Luminescence Methods.

BACKGROUND: The paradigm shift towards the nonsurgical management of dental caries relies on the early detection of the disease. Detection of caries at an early stage is of unequivocal importance for early preventive intervention. OBJECTIVE: The aim of this in vitro study is to evaluate the performance of a visual examination using the International Caries Detection and Assessment System (ICDAS) criteria, two quantitative light-induced fluorescence (QLF) systems--Inspektor™ Pro and QLF-D Biluminator™ 2 (Inspektor Research Systems B.V., Amsterdam, The Netherlands)--and a photothermal radiometry and modulated luminescence, The Canary System® (Quantum Dental Technologies, Toronto, Ont., Canada) on the detection of primary occlusal caries on permanent teeth. METHODS: A total of 60 teeth with occlusal surface sites ranging from sound to noncavitated lesions (ICDAS 0-4) were assessed with each detection method twice in a random order. Histological validation was used to compare methods for sensitivity, specificity, percent correct, and the area under the receiver operating characteristic curve (AUC), at standard and optimum sound thresholds. Interexaminer agreement and intraexaminer repeatability were measured using intraclass correlation coefficients. RESULTS: Interexaminer agreement ranged between 0.48 (The Canary System®) and 0.96 (QLF-D Biluminator™ 2). Intraexaminer repeatability ranges were 0.33-0.63 (The Canary System®) and 0.96-0.99 (QLF-D Biluminator™ 2). The sensitivity range was 0.75-0.96 while that of specificity was 0.43-0.89. The AUC were 0.79 (The Canary System®), 0.87 (ICDAS), 0.90 (Inspektor™ Pro), and 0.94 (QLF-D Biluminator™ 2). CONCLUSION: ICDAS had the best combination of sensitivity and specificity followed by QLF-D Biluminator™ 2 at optimum threshold.

In vitro effect of calcium-containing prescription-strength fluoride toothpastes on bovine enamel erosion under hyposalivation-simulating conditions.

PURPOSE: To evaluate the ability of calcium-containing prescription-strength fluoride (F) toothpastes in preventing enamel erosion under low salivary flow simulating conditions. METHODS: Enamel and dentin bovine specimens were assigned to the following groups: A - placebo; B - 1,100 ppm F/NaF (Aquafresh Advanced); C - 5,000 ppm F/NaF (Prevident 5000 Booster); D - 5000 ppm F/NaF+calcium sodium phosphosilicate (Topex Renew); and E - 5,000 ppm F/NaF+tri-calcium phosphate (Clinpro 5000). Specimens were positioned in custom-made devices, creating a sealed chamber on the surface, connected to peristaltic pumps. Citric acid was injected into the chamber for 2 minutes, followed by artificial saliva (0.05 ml/minute), for 60 minutes, 4x/day, for 3 days. Aquafresh was also tested under normal salivary flow (0.5 ml/minute), as reference (Group F). Specimens were exposed to the toothpastes for 2 minutes, 2x/day. After cycling, surface loss (SL) and concentration of loosely- and firmly-bound F were determined. Data were analyzed by ANOVA. Results: Group A (placebo) presented highest surface loss (SL), while Group F had the lowest, for both substrates. For enamel, none of the dentifrices differed from Group B or among each other. For dentin, none of the dentifrices differed from Group B, but Group E showed greater protection than Group C. Group E presented the highest F concentrations for both substrates, only matched by Group D for firmly-bound fluoride on enamel. All fluoridated dentifrices tested reduced SL, with no additional benefit from higher F concentrations. Some formulations, especially Clinpro 5000, increased F availability on the dental substrates, but no further erosion protection was observed.

Exploratory Randomized Clinical Trial of an Experimental Gel-to-Foam Fluoride Dentifrice Formulation Using an In Situ Caries Model.

OBJECTIVE: To evaluate the in situ caries performance and safety of two experimental fluoride dentifrice formulations (1450 ppm fluoride) with and without 2% isopentane as an excipient, in comparison to a positive control, currently marketed dentifrice (1450 ppm fluoride) and a negative control dentifrice (0 ppm fluoride). METHODS: This was a single-center, examiner-blind, randomized, controlled, four-treatment cross-over study. During each treatment period, the subject wore a modified mandibular partial denture fitted with two gauze-covered, partially demineralized human enamel specimens, and brushed at home for one timed minute, twice daily, for two weeks. At the end of each treatment period, the enamel specimens were removed from the dentures for analysis. During the week between treatment periods, subjects returned to their usual dental hygiene practices for four to five days, received a dental prophylaxis, and used a study-designated non-fluoride dentifrice for two to three days before starting the next treatment. Treatment effect on enamel specimen remineralization was assessed by surface microhardness (SMH). Enamel fluoride uptake was assessed using microdrill enamel biopsy. RESULTS: All fluoride-containing dentifrices demonstrated significant, superior SMH recovery and levels of fluoride uptake compared to the negative control dentifrice. No significant differences were observed for either efficacy variable between the experimental dentifrice formulations and the positive control dentifrice. No significant difference was observed between the 2% isopentane dentifrice and the 0% isopentane dentifrice for SMH recovery. CONCLUSION: The addition of 2% isopentane did not positively or negatively affect fluoride efficacy in this model.

Novel in-situ longitudinal model for the study of dentifrices on dental erosion-abrasion.

A novel longitudinal erosion-abrasion in-situ model was proposed. In an exploratory test (phase 1) toothbrushing effect was investigated using a parallel design, whereas in the main study (phases 1 + 2), a crossover design tested the effect of fluoride dentifrice. In phase 1, 16 subjects (n = 5-6 subjects per group) wore partial dentures with enamel specimens for 28 d and adhered to one of the following treatment regimens: regimen A, erosion only; regimen B, erosion + toothbrushing with fluoride-containing dentifrice [1,100 ppm of fluoride as sodium fluoride (NaF)]; and regimen C, erosion + toothbrushing with placebo dentifrice (0 ppm fluoride). Erosion consisted of the exposure of specimens to grapefruit juice. In regimens B and C, toothbrushing was performed with the test dentifrices 5 min after erosion. For the main study a second phase was carried out in which subjects initially treated with regimen B were treated with regimen C, and vice versa (crossover, n = 11), repeating the same experimental protocol. Enamel wear was measured by optical profilometry at baseline and every 7 d thereafter. In the exploratory test (phase 1), no significant differences were observed among regimens at any of the study time-points. In the main study (phases 1 + 2), higher enamel wear was observed for regimen C than for regimen B. A significant trend was observed for the increase of enamel wear over time. Fluoridated dentifrice reduced the development of erosive-abrasive lesions. The proposed longitudinal model provided adequate responses for erosion-abrasion frequency and fluoride effects.

Erosion protection by calcium lactate/sodium fluoride rinses under different salivary flows in vitro.

This study investigated the effect of a calcium lactate prerinse on sodium fluoride protection in an in vitro erosion-remineralization model simulating two different salivary flow rates. Enamel and dentin specimens were randomly assigned to 6 groups (n = 8), according to the combination between rinse treatments - deionized water (DIW), 12 mM NaF (NaF) or 150 mM calcium lactate followed by NaF (CaL + NaF) - and unstimulated salivary flow rates - 0.5 or 0.05 ml/min - simulating normal and low salivary flow rates, respectively. The specimens were placed into custom-made devices, creating a sealed chamber on the specimen surface connected to a peristaltic pump. Citric acid was injected into the chamber for 2 min, followed by artificial saliva (0.5 or 0.05 ml/min) for 60 min. This cycle was repeated 4×/day for 3 days. Rinse treatments were performed daily 30 min after the 1st and 4th erosive challenges, for 1 min each time. Surface loss was determined by optical profilometry. KOH-soluble fluoride and structurally bound fluoride were determined in specimens at the end of the experiment. Data were analyzed by 2-way ANOVA and Tukey tests (α = 0.05). NaF and CaL + NaF exhibited significantly lower enamel and dentin loss than DIW, with no difference between them for normal flow conditions. The low salivary flow rate increased enamel and dentin loss, except for CaL + NaF, which presented overall higher KOH-soluble and structurally bound fluoride levels. The results suggest that the NaF rinse was able to reduce erosion progression. Although the CaL prerinse considerably increased F availability, it enhanced NaF protection against dentin erosion only under hyposalivatory conditions.

The effect of dentifrice quantity and toothbrushing behaviour on oral delivery and retention of fluoride in vivo.

While toothpaste F(-) concentration and rinsing regimen have well-characterised impacts on fluoride's effectiveness, other aspects of brushing regimen have much less well-established effects, in particular, dentifrice quantity and brushing duration. An in vivo study (n = 42) of oral fluoride delivery (i.e. oral disposition post-brushing), and retention (i.e. concentration of F(-) in saliva post-brushing, a known efficacy predictor), was performed to compare effects observed with those of dentifrice F(-) concentration and rinsing regimen. Subjects brushed with a NaF-silica dentifrice (Aquafresh Advanced, 1,150 ppm F(-) ) or a control dentifrice (250 ppm F(-) , same base), for 45, 60, 120 or 180 seconds with 0.5 or 1.5 g dentifrice, and rinsed with 15 ml water once or three times in a cross-over design. The F(-) concentration was measured in post-brushing expectorate, rinse and toothbrush washing samples, and in saliva between 5-120 minutes after brushing. Using 1.5 g versus 0.5 g dentifrice increased F(-) in all samples: oral retention of F(-) was almost doubled by this increase. Increasing duration of brushing had more complex effects. The amount of F(-) in the expectorate increased but decreased in both rinse and toothbrush washing samples. Oral F(-) retention increased, but only in the period 30-120 minutes after brushing. Over the ranges investigated, the order of importance on oral F(-) retention was: dentifrice F(-) concentration > quantity > rinsing regimen > brushing duration. Hence, increasing dentifrice quantity and, to a lesser extent, the duration of brushing, can elevate oral fluoride post-brushing. Evidence is accumulating that the importance of these variables to fluoride efficacy may have been underestimated.