Effect of calcium fluoride nanoparticles in prevention of demineralization during orthodontic fixed appliance treatment: a randomized clinical trial.

BACKGROUND: White spot lesions (WSLs) are the most common complications of fixed appliance orthodontic treatment. OBJECTIVES: To evaluate the effectiveness of calcium fluoride nanoparticles-containing orthodontic primer (nCaF2-primer) in preventing the incidence of WSLs during orthodontic treatment. TRIAL DESIGN: Single-centre, double-blinded, split-mouth, randomized clinical trial. METHODS: The sample involved 31 orthodontic patients (≥12 years). Participants were recruited using a simple nonstratified randomization. Data collection, measurements, and analysis were performed blindly. Outcome measures included comparing the effect of nCaF2-primer with control primer (Transbond) regarding the degree of demineralization (DIAGNOdent pen), Streptococcus mutans (S. mutans) bacterial counting [real-time polymerase chain reaction device (PCR)], and WSLs incidence (pre- and post-operative photographs). The measurements were performed before bonding, 1, 3, and 6 months after bonding and after appliance removal. A two-way repeated measure analysis of variance test (for DIAGNOdent pen scores), and Wilcoxon signed-rank test (for the difference between bacterial counting and WSLs incidence) were used (P < 0.05). RESULTS: Thirty-one patients were recruited and randomized (mean age 17.9 ± 2.45 years). For the primary outcome (DIAGNOdent pen scores) and secondary outcome of S. mutans counting: 31 patients (310 teeth for each group) were included in scoring at T1 and T3, and 30 patients (300 teeth) were included at T6. While for the photographic scores, 26 patients were included after bracket bonding. The demineralization scores showed significant differences at all-time intervals within the 6 months after bracket bonding which was more noticeable after the first month. There was a significant difference in bacterial count between the two primer groups at the T1 only. Regarding photographic scores, there were no significant differences in the WSLs incidence between the two primers groups after brackets removal. No harm was detected during treatment, except the usual pain/gingival irritation. CONCLUSIONS: nCaF2-primer effectively decreased demineralization scores within the 6 months after bracket bonding. Moreover, it significantly reduced S. mutans colonization after the first month. However, the tested primer did not have an extra advantage in preventing WSLs development at the clinical level after appliance removal. TRIAL REGISTRATION: The trial was registered with ClinicalTrials.gov on 8 May 2021 (registration number: NCT04994314).

Mineral Nanomedicine to Enhance the Efficacy of Adjuvant Radiotherapy for Treating Osteosarcoma.

It is vital to remove residual tumor cells after resection to avoid the recurrence and metastasis of osteosarcoma. In this study, a mineral nanomedicine, europium-doped calcium fluoride (CaF2:Eu) nanoparticles (NPs), is developed to enhance the efficacy of adjuvant radiotherapy (i.e., surgical resection followed by radiotherapy) for tumor cell growth and metastasis of osteosarcoma. In vitro studies show that CaF2:Eu NPs (200 µg/mL) exert osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects at a Eu dopant amount of 2.95 atomic weight percentage. These effects are further enhanced under X-ray irradiation (6 MeV, 4 Gy). Furthermore, in vivo tests show that intraosseous injection of CaF2:Eu NPs and X-ray irradiation have satisfactory therapeutic efficacy in controlling primary tumor size and inhibiting primary tumor metastasis. Overall, our results suggest that CaF2:Eu NPs with their osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects combined with radiotherapy might be nanomedicines for treating osteosarcoma after tumor resection.

Comparative Effect of Calcium Mesoporous Silica Versus Calcium and/or Fluoride Products on the Reduction of Erosive Tooth Wear and Abrasive Enamel Lesion

Abstract Objective: To evaluate the effect of a calcium nanocompound on the reduction of erosive tooth wear and abrasion. Material and Methods: Bovine enamel specimens (BE), were randomly assigned to the following groups (n = 10): G1 = Calcium mesoporous silica nanoparticles (Ca2+MSNs); G2 = casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, 2% CPP-ACP, GC®); G3 = casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP, 2% CPP-ACP + 900 ppm F-, GC®); G4 = sodium fluoride NaF (900 ppm F-, positive control); and G5 = distilled and deionized water (negative control). Each product was applied to the exposed area for one minute, three times per day for three consecutive days, and followed by the immersion of the specimens in Sprite Zero™ - a low-pH solution (2.58) for five minutes (Coca-Cola™). After the first and last erosive challenges of the day, the specimens were submitted to abrasion in a toothbrush machine for 15 seconds (200 g/BE). The specimens were analysed using 3D non-contact optical profilometry, with tooth structure loss (TSL) measurements and scanning electron microscopy (SEM). TSL values were analysed by Kruskal-Wallis and Mann-Whitney tests (p<0.05). Results: There were no significant differences between G1 (10.95 µm) and G3 (10.80 µm) treatments for TSL values; however both resulted in significantly reduced TSL values compared with the G5 (16.00 µm) (p<0.05). The G4 (12.26 µm) showed no statistically significant difference when compared to the G5 (16.00 µm). The groups G1 and G3 presented higher surface preservation than the G5. Conclusion: Ca2+MSNs was effective for reducing tooth surface loss caused by erosive tooth wear and abrasion.

Calcium-based biomaterials for diagnosis, treatment, and theranostics.

Calcium-based (CaXs) biomaterials including calcium phosphates, calcium carbonates, calcium silicate and calcium fluoride have been widely utilized in the biomedical field owing to their excellent biocompatibility and biodegradability. In recent years, CaXs biomaterials have been strategically integrated with imaging contrast agents and therapeutic agents for various molecular imaging modalities including fluorescence imaging, magnetic resonance imaging, ultrasound imaging or multimodal imaging, as well as for various therapeutic approaches including chemotherapy, gene therapy, hyperthermia therapy, photodynamic therapy, radiation therapy, or combination therapy, even imaging-guided therapy. Compared with other inorganic biomaterials such as silica-, carbon-, and gold-based biomaterials, CaXs biomaterials can dissolve into nontoxic ions and participate in the normal metabolism of organisms. Thus, they offer safer clinical solutions for disease theranostics. This review focuses on the state-of-the-art progress in CaXs biomaterials, which covers from their categories, characteristics and preparation methods to their bioapplications including diagnosis, treatment, and theranostics. Moreover, the current trends and key problems as well as the future prospects and challenges of CaXs biomaterials are also discussed at the end.

Antibacterial Properties of Calcium Fluoride-Based Composite Materials: In Vitro Study.

The aim of the study was to evaluate antibacterial activity of composite materials modified with calcium fluoride against cariogenic bacteria S. mutans and L. acidophilus. One commercially available conventional light-curing composite material containing fluoride ions (F2) and two commercially available flowable light-curing composite materials (Flow Art and X-Flow) modified with 1.5, 2.5, and 5.0 wt% anhydrous calcium fluoride addition were used in the study. Composite material samples were incubated in 0.95% NaCl at 35°C for 3 days; then dilution series of S. mutans and L. acidophilus strains were made from the eluates. Bacteria dilutions were cultivated on media afterwards. Colony-forming unit per 1 mL of solution (CFU/mL) was calculated. Composite materials modified with calcium fluoride highly reduced (p < 0.001) bacteria growth compared to commercially available composite materials containing fluoride compounds. The greatest reduction in bacteria growth was observed for composite materials modified with 1.5% wt. CaF2. All three tested composite materials showed statistically greater antibacterial activity against L. acidophilus than against S. mutans.

Efficacy of pastes containing CPP-ACP and CPP-ACFP in patients with Sjögren's syndrome.

OBJECTIVES: The purpose of this study was to evaluate efficacy of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP) containing pastes among individuals with Sjögren's syndrome (SS). MATERIALS AND METHODS: Thirty patients were randomised into three groups: CPP-ACP, CPP-ACFP, and 0.05 % NaF to be used two times a day during a 28-day experimental period. Saliva was analysed for flow rate, pH, buffering capacity and mineral concentrations. Dental plaque was examined for pH. Following the formation of artificial carious lesion, participants wore enamel slabs for an in situ remineralisation study. Remineralisation potential was examined using scanning electron microscope (SEM) and energy dispersive spectroscopic (EDS) technique. SE microphotographs were subsequently analysed for area, diameter, perimeter, roundness and the number of enamel defects and percentage of tooth surface affected by defects. RESULTS: At the end of the experimental period, a slight increase of salivary pH could have been observed. No differences in mineral composition of saliva were noted. The use of CPP-ACP and CPP-ACFP contributed to a significant rise of plaque pH. Image analysis revealed excessive reduction of defects' dimensions in the three experimental groups, and a decrease of the number of enamel defects in the CPP-ACP and CPP-ACFP groups. The EDS analysis did not show differences in Ca/P, Ca/O and P/O ratios in any of the treatment groups. CONCLUSION: CPP-ACP and CPP-ACFP hold promise as remineralising agents for patients with SS. CLINICAL RELEVANCE: Pastes containing CPP-ACP/CPP-ACFP show enhanced remineralisation potential compared with NaF mouthrinse in patients with SS.

The influence of varnish and high fluoride on erosion and abrasion in a laboratory investigation.

BACKGROUND: The aim of this study was to investigate the potential of concentrated fluoride varnishes to reduce enamel loss from repeated cycles of citric acid erosion and toothbrush abrasion in vitro. METHODS: Polished human enamel samples were exposed to fluoride varnishes: Bifluorid10® (NaF&CaF2- 45,200 ppmF), Duraphat® (NaF 22,600 ppmF), Fluor-Protector® (difluorsilane 1000 ppmF) and a control coating of copal ether varnish (0 ppmF) group and a deionized water group. For each group of 16 samples, nine cycles of erosion and nine cycles of erosion-abrasion [1 cycle=erosion (0.3% citric acid, pH 3.2, 5 min)+artificial saliva (1 h, pH 7.0)+abrasion (120 linear strokes in artificial saliva from Oral B medium soft brushes 300 g loading]. The change in the enamel surface was evaluated using optical profilometry. RESULTS: Duraphat® and Bifluorid10® applications had a median (IQR) step height of 4.21 um (1.59) and 5.01 um (1.02). This was statistically significantly less than Fluor-Protector® 6.83 um (1.25), copal ether 7.22 um (1.97) and water 7.39 um (1.96) (p<0.001). For erosion-abrasion, both Duraphat® and Bifluorid® had statistically lower step heights than the other products (p<0.01). CONCLUSIONS: The action of fluoride in a range of single-application topical varnishes was effective in reducing enamel wear from erosion and erosion-abrasion in this laboratory study.

The effect of single-application fluoride treatment on simulated gastric erosion and erosion-abrasion of enamel in vitro.

PURPOSE: To compare single-application fluoride formulations on enamel erosion and erosion-abrasion in vitro. MATERIALS AND METHODS: Enamel specimens were pretreated with either sodium, tin, titanium, or sodium/calcium fluoride and subjected to either an erosion model or an erosion-abrasion model, after which optical profilometry was used to measure enamel step height loss. RESULTS: For erosion, the titanium fluoride (P < .001) reduced enamel loss, whereas the calcium, tin, and sodium treatments showed no significant effects (P > .05). For erosion-abrasion, the titanium fluoride increased enamel loss in comparison to control (P < .001). CONCLUSIONS: Titanium fluoride has differing effects on enamel loss from erosion and erosion-abrasion models.

Approximal caries increment in adolescents in a low caries prevalence area in Sweden after a 3.5-year school-based fluoride varnish programme with Bifluorid 12 and Duraphat.

OBJECTIVES: To evaluate approximal caries increment among 12- to 16-year-olds in a low caries prevalence area in Sweden after a 3.5-year school-based fluoride (F) varnish programme with Bifluorid 12 and Duraphat. METHODS: The design was a RCT study with 1365 adolescents, divided into following four groups: Group 1 Bifluorid 12 two applications/year; Group 2 Duraphat two applications/year; Group 3 Bifluorid 12 four applications/year and Group 4 no F varnish at school. 1143 children (84%) completed the study. Approximal caries was registered on bitewing radiographs. RESULTS: There were no statistically significant differences in caries prevalence among the groups either at baseline or after 3.5 years . The caries increment for Group 1 was 1.34 ± 2.99 (mean ± SD), 1.24 ± 2.84 for Group 2, 1.07 ± 2.66 for Group 3 and 1.25 ± 2.75 for Group 4, with no statically significant differences either between Bifluorid 12 and Duraphat with the same frequency of F varnish applications or between the F groups and the control group. CONCLUSIONS: In an area with low caries prevalence in Sweden, the supplementary caries-preventive effect of school-based F varnish applications, to regular use of F toothpaste at home and to regular caries prevention given at the Public Dental Clinics, appears to be nonsignificant regarding approximal caries increment.

Retention of KOH-soluble fluoride formed after application of a SnCl(2)/AmF/NaF containing mouth rinse under erosive conditions.

OBJECTIVE: Application of SnCl(2)/AmF/NaF containing mouth rinse showed good protection against erosion. The aim of the study was to evaluate if this is due to the amount of KOH-soluble fluoride (KOHsF) formed or its resistance under erosive conditions. METHODS: One hundred and fifty bovine enamel samples were allocated to five groups (n = 30) and were once eroded in 0.05 mol/l citric acid (5 min). Samples were stored in artificial saliva for 4 days. Samples of two groups (erosive-SnCl(2) + erosive-NaF) were eroded 6 × for 5 min. The remaining samples were stored in aqua dest deionised water. Each day the samples were treated twice for 2 min with 1 ml SnCl(2)/AmF/NaF-solution (erosive-SnCl(2);neutral-SnCl(2)/AmF/NaF) or NaF-solution (erosive-NaF;neutral-NaF). The fifth group remained untreated (control). On day 5, 10 samples of each group were used for determination of KOHsF (series 1). The remaining samples were again eroded (erosive-SnCl(2) + erosive-NaF) or stored in artificial saliva (neutral-SnCl(2) + neutral-NaF). KOHsF of another 10 samples of each group was measured (series 2). The last 10 samples of each group were also treated as described above and the amount of KOHsF was measured (series 3). RESULTS: In each series 1-3 KOHsF in group erosive-SnCl(2)/AmF/NaF were significantly higher. No significant loss of KOHsF between the series 1-3 was observed (except for control). CONCLUSION: SnCl(2)/AmF/NaF containing mouth rinse revealed a better formation of KOH-soluble fluoride as the NaF-solution, although the applied fluoride compound has no influence on the stability of the KOHsF under erosive conditions, leading to the conclusion that the resistance of KOHsF is not responsible for the difference in the protection against dental erosion.

Clinical evaluation of demineralization and remineralization of intact root surface lesions in the clinic by a quantitative light-induced fluorescence system.

Detection of demineralization of root surface caries is an important issue since preventive approaches prolong tooth life. Quantitative light-induced fluorescence (QLF) has been shown to be useful for the laboratory assessment of demineralization of root surfaces. The aim of this study was to determine the demineralization and remineralization of root surface intact and cavitated caries lesions using a QLF system as a nondestructive in vivo method. Noncavitated and demineralized root surface lesions were detected and scored using the QLF system. Oral hygiene education was given and periodontal cleaning was completed before the remineralization treatment. After obtaining baseline QLF data, the patients were informed about the remineralization treatment. Fluoride varnish was applied to the carious lesions at the baseline visit, and the patients were then reviewed after 1, 2, 3 and 4 weeks, with QLF assessment and fluoride varnish application repeated at each review. Repeated-measures ANOVA (α = 0.05) showed significant differences between ΔQ values at each visit (p < 0.001); ΔQ showed marked decreases at all the cut-off values (15, 20, 25, 30). The changes in ΔQ were not affected by the cut-off value. The ΔQ values of QLF showed differences at all visits. The QLF system was able to detect early root surface caries lesions in vivo. Bifluoride 12 varnish improved mineral levels as shown by the QLF system. The treatment response to chemicals of intact noncavitated root surface carious lesions could be followed nondestructively in the clinic using QLF to quantify remineralization at recall visits. Teeth with root surface caries can be kept by controlling their remineralization.

Comparative evaluation of two commercially available desensitizing agents for the treatment of dentinal hypersensitivity.

AIMS: A randomized clinical trail was designed to compare the efficacy of two commercially available desensitizing agents (fluoride varnish containing 6% sodium fluoride and 6% calcium fluoride and a gel containing 6% potassium nitrate and 0.11% fluoride ions) in the treatment of dentinal hypersensitivity. SETTINGS AND DESIGN: Randomized clinical trial. MATERIALS AND METHODS: Twenty-one patients were selected. Subjects were evaluated using three different stimuli, i.e., tactile test, air blast test and cold water test. They were then randomly divided into two groups. Patients in group I were treated with fluoride varnish and group II patients were treated with gel containing 6% potassium nitrate and 0.11% fluoride ions. The patients were examined at baseline, immediately after application of the agent, at 1 week, 1 month and 3 months interval. STATISTICAL ANALYSIS: Statistical analysis was done using unpaired "t" test, paired "t" test and Chi-square test with Yate's correction. RESULTS: The results were analyzed; it was seen that patients treated in group I showed significantly better results compared to group II patients at 1 month and 3 months interval. Teeth which required repeat dose and those which did not require repeat dose were comparable in number. CONCLUSIONS: Both the agents showed significant reduction in sensitivity at all time intervals compared to baseline. A comparatively significant reduction in sensitivity score was seen in patients treated with fluoride varnish and it appeared to be more effective in providing long-term relief against all the three test stimuli. Teeth with initial high sensitivity score required repeat doses, which was comparable for both the groups.

Mineral distribution of artificial dentinal caries lesions after treatment with fluoride agents in combination with saliva substitutes.

OBJECTIVE: Some saliva substitutes have been shown to demineralize dentine in vitro. This effect is counteracted by the application of various fluorides. In contrast, remineralizing saliva substitutes might be supported by these treatments, depending on the dynamics during remineralization. The aim of this in vitro study was to evaluate the effects of fluoride mouthrinses or gels in combination with de-/remineralizing saliva substitutes on dentinal subsurface lesions. DESIGN: Demineralized bovine dentine specimens were stored either in mineral water [saturation with respect to octacalcium phosphate (S(OCP)): 0.7], Glandosane (G, S(OCP): 0.3) or in a modified saliva substitute Saliva natura (SN, S(OCP): 1.9) for five weeks (37°C). Fluoride agents were applied twice daily for 10 min (n = 15/group): no treatment, Meridol mouthrinse, Elmex sensitive solution, ProSchmelz fluoride gel, Elmex gelée. After storage thin sections were prepared and mineral losses before and after storage were evaluated from microradiographs. RESULTS: Specimens stored in G alone showed significantly higher mineral loss compared to those stored in water, SN or G in combination with any additional treatment (p < 0.05). Storage in SN and treatment with ProSchmelz fluoride gel led to significantly higher remineralization compared to all other groups (p < 0.05) and resulted in distinct mineral gain within the lesion body. CONCLUSIONS: Under the in vitro conditions chosen, use of fluoride agents in combination with a demineralizing saliva substitute resulted in reduced mineral loss. Storage in modified Saliva natura in combination with the application of ProSchmelz fluoride gel induced the most pronounced remineralization also of deeper lesion areas.

Comparative in vivo study on the desensitizing efficacy of dentin desensitizers and one-bottle self-etching adhesives.

UNLABELLED: This in vivo study evaluated the desensitizing efficacy of two one-bottle self-etching adhesives, two dentin desensitizers and a placebo (water). METHODS: Thirty-one volunteers with 55 hypersensitive teeth were recruited into this clinical investigation. The sensitive teeth were randomly assigned into five groups and treated with one of the following materials: iBond, Heraeus; Xeno V, Dentsply; Gluma desensitizer, Heraeus; Bifluorid 12, Voco; placebo (water). Mechanical and thermal stimuli were used to assess the tooth sensitivity response. Discomfort interval scale (DIS) scores of the sensitive teeth were recorded at three different investigation times (baseline, immediately and one month after treatment). Impressions were taken from the sensitive teeth at all three different investigation times, and replica models were made for the evaluation of the dentin surfaces by scanning electron microscopy. The Friedman test and the Mann Whitney U-test were used to analyze the data. RESULTS: All dental materials significantly reduced the dentin hypersensitivity immediately (p < 0.05) and one month after treatment (p < 0.05), with the exception of Bifluorid 12 for mechanical tooth sensitivity. The placebo (water) only caused a short-term effect on the thermal dentin hypersensitivity (p < 0.05). Topical application of the dentin adhesives/desensitizers on sensitive dentinal areas resulted in occlusion of the patent tubules. CONCLUSIONS: The one-bottle self-etching adhesives and dentin desensitizers involved in the current clinical investigation could significantly relieve dentin hypersensitivity immediately and over the course of a month after treatment (except for Bifluorid 12 for tooth mechanical sensitivity). The placebo (water) had an immediate effect on thermal dentin hypersensitivity.

Effects of carboxymethyl cellulose-based saliva substitutes with varying degrees of saturation with respect to calcium phosphates on artificial enamel lesions.

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

Comparative evaluation of Nd:YAG laser and fluoride varnish for the treatment of dentinal hypersensitivity.

INTRODUCTION: Various methods and materials are used in the treatment of dentin hypersensitivity. The aim of this randomized prospective controlled clinical trial was to evaluate and compare the desensitizing effects of the neodymium-doped yttrium aluminium garnet (Nd:YAG) laser and fluoride varnish by considering the degree of pre- and posttreatment pain, discomfort, and functional complications. METHODS: Twenty patients with clinically diagnosed cervical dentin hypersensitive teeth were included and randomly allocated to either the application of fluoride varnish (group fluoride) or Nd:YAG laser (100 mJ, 20 Hz; group Nd:YAG). The assessment of pain and discomfort was performed by a visual analog scale after an air blast at baseline, immediately after treatment, and at patient visits on weeks 1, 2, 3, and 4. RESULTS: Laser treatment resulted in significant improvements of discomfort immediately after treatment and after 1 week. At the 2-, 3-, and 4-week examination, the discomfort in group fluoride decreased up to nearly 75% to 85% of baseline scores, whereas the effect of the laser stayed nearly unchanged. The visual analog scale scores for pain at 4 weeks examination were significantly lower in the fluoride group compared with those in the laser group (p < 0.05). CONCLUSIONS: Nd:YAG laser is a suitable tool for the immediately successful reduction of dentinal hypersensitivity and has better patient satisfaction and shorter treatment time.

Effect of fluoride varnish on enamel demineralization around brackets: an in-vivo study.

INTRODUCTION: Even with advances in materials and techniques, demineralization around brackets during orthodontic treatment continues to be a problem. The purpose of this in-vivo study was to evaluate the effect of a fluoride varnish on enamel demineralization adjacent to bonded brackets. METHODS: Fifteen patients who needed at least 2 premolars extracted for orthodontic reasons were selected. In each patient, 1 premolar was considered the test tooth, and the other was the control. Brackets were bonded, and T-loops were engaged on all premolars, but only the test teeth received fluoride varnish. The premolars were extracted after 85 to 95 days, and buccolingual sections 50 to 70 microm in thickness were evaluated with polarized light microscopy. The mean depth of demineralization in each lesion was measured 3 times on photographs by an operator blinded to the groups (intraclass correlation of the 3 measurements was 0.988). RESULTS: The mean lesion depths were 57.0 +/- 5.5 microm in the test group and 94.3 +/- 6.7 microm in the control group. There was significant reduction (approximately 40%) in depth of demineralization in the test group (P <.001). CONCLUSIONS: Fluoride varnish can be beneficial as a preventive adjunct in reducing demineralization adjacent to brackets.

Tooth wear prevention: a quantitative and qualitative in vitro study.

BACKGROUND: Management of tooth wear from grinding presents a significant clinical challenge. Acrylic nightguards are often used to protect the teeth, but many patients still grind with these appliances. This study aimed to test the effectiveness of three lubricants in reducing enamel wear by using an electro-mechanical machine under controlled conditions, with a view to undertaking a subsequent longitudinal clinical study. METHODS: Sectioned tooth specimens were worn against each other under different loads and with the addition of three different lubricants: calcium fluoride (CaF) powder, olive-oil, and a combination of calcium fluoride with olive-oil in the form of a slurry. Wear rates of enamel only were quantified by weighing the specimens, and resin replicas of the worn tooth surfaces were made for examination under a scanning electron microscope. RESULTS: All three lubricants reduced the amount of enamel wear significantly compared with wearing specimens without adding lubricants. Wear rate was influenced by the type of lubricant and the load applied. Wear rates were significantly less for olive-oil and the olive-oil/CaF slurry compared with CaF alone. The microwear detail differed between the three lubricants. CONCLUSIONS: This study has shown that enamel wear can be reduced using dry or wet lubricants between opposing teeth that are worn under controlled conditions. Further research is required to clarify their possible clinical applications.