What is the effectiveness of titanium tetrafluoride to prevent or treat dental caries and tooth erosion? A systematic review

OBJECTIVES

Answer the question: What is the effectiveness of titanium tetrafluoride (TiF₄) when compared to other fluorides, placebo solution or a negative control to prevent or treat dental caries and tooth erosion?

MATERIALS AND METHODS

This review is in accordance with PRISMA guidelines. In vivo and in situ studies that used TiF₄ over enamel or dentine were included. Electronic searches were conducted on MEDLINE, Scopus, Embase, WOS, Cochrane Library, VLH, Clinical Trials and OpenGrey. Risk of bias (ROB) assessments used RoB2 and ROBINS-I for randomized and non-randomized controlled trials (RCTs and on-RCTs); Syrcle's ROB tool for animal studies; and a modified tool proposed by Hollanders for in situ studies.

RESULTS

A total of 28 studies met the eligibility criteria. From these, 6 were in humans (3 RCT and 3 Non-RCT); 4 were in animals and 18 were in situ. For in vivo studies, all RCTs have some concerns related to ROB and all of the non-RCT studies were classified as with serious risk. One animal study had a low and three a high ROB. Regarding in situ studies, seven had a low, ten had an average and only one had a high ROB. The certainty of the evidence (GRADE) ranged from moderate to very low.

CONCLUSIONS

Although most of the results suggest a positive effect of TiF4 on the prevention and treatment of caries and dental erosion, it is not possible to have definitive conclusions due to the high studies' methodological heterogeneity, and the low quality of evidence for most outcomes.

REGISTRATION

The protocol of this syste. atic review was registered in the OPEN SCIENCE FRAMEWORK database (osf.io/6dgs9) DOI:10.17605/OSF.IO/KUZA7 on 6 August 2020.

Knowledge on and treatment practices of erosive tooth wear among Finnish dentists

OBJECTIVES

To investigate Finnish dentists' knowledge on and means of recording, detecting and diagnosing erosive tooth wear (ETW). Treatment options and possible differences in treatment decisions between general and specialized dentists were also evaluated.

MATERIALS AND METHODS

An electronic questionnaire was sent by e-mail to 3664 Finnish dentists. Respondents' gender, age, work experience, field of specialty, and practice location were requested. The questionnaire also included a patient case where the dentists were asked about their choice of treatment. Statistical analyses were performed using means, proportions, and cross tabulations.

RESULTS

Response rate was 24% (n = 866). Almost all respondents (98.0%) recorded ETW in patient files, but only 4.1% used a detailed scoring system. Of the respondents, 64.4% usually found the cause of ETW. Use of carbonated beverages (84.3%), energy drinks (57.0%), and reflux disease (53.1%) were reported to be probable causes. The majority of the respondents (80.9%) usually assessed patient's dietary history while 1.9% evaluated saliva secretion rate. When asked about treatment decisions of ETW patients, the differences between general dentists and specialized dentists were not as obvious as hypothesized.

CONCLUSIONS

This study suggests that the Finnish dentists who participated in this survey are able to detect and/or diagnose erosive tooth wear, but there is variation in recording it. The differences in treatment decisions between general dentists and specialized dentists seem to be moderate. The treatment practices for ETW are not established and further research to create clinical guidelines seems to be needed.

Progress and limitations of current surface registration methods when measuring natural enamel wear

OBJECTIVES

Our ability to detect dental wear on sequential scans is improving. This experiment aimed to determine if widely used surface registration methods were sufficiently accurate to distinguish differences between intervention groups on early wear lesions.

METHODS

Baseline measurements were taken on human molar buccal enamel samples (n = 96) with a confocal scanning profilometer (Taicaan, UK). Samples were randomly assigned to subgroups of brushing (30 linear strokes 300 g force) before or after an acid challenge (10 min citric acid 0.3% immersion) for four test dentifrices (medium abrasivity NaF, medium abrasivity SnF₂, low abrasivity NaF and a water control). Post-experimental profilometry was repeated. 3D step height was analysed using WearCompare (www.leedsdigitaldentistry.co.uk/wearcompare, UK). Percentage Sa change was calculated using Boddies (Taicaan Technologies, Southampton, UK). Data were analysed in SPSS (IBM, USA).

RESULTS

The mean 3D step height (SD) observed when samples were brushed before the erosive challenge was -2.33 µm (3.46) and after was -3.5 µm (5.6). No significant differences were observed between timing of toothbrushing or dentifrice used. The mean % Sa change for the low abrasivity group (water control and low abrasivity NaF) was -10.7% (16.8%) and +28.0% (42.0%) for the medium abrasivity group (medium abrasivity NaF and SnF₂).

CONCLUSIONS

Detectable wear scars were observed at early stages of wear progression. However standard deviations were high and the experiment was underpowered to detect significant changes. Brushing with a low abrasivity dentifrice or water control produced a smoother surface whereas brushing with a high abrasivity dentifrice produced a rougher surface.

CLINICAL SIGNIFICANCE

The methodology currently used to align sequential scans of teeth and measure change is too imprecise to measure early wear on natural enamel surfaces unless a large sample size is used. Further improvements are required before we can fully assess early wear processes on natural teeth using profilometry.

Effect of tooth bleaching and application of different dentifrices on enamel properties under normal and hyposalivation conditions: an in situ study

OBJECTIVE

The purpose of this in situ study was to evaluate different dentifrices on enamel after bleaching under normal and hyposalivatory conditions.

MATERIALS AND METHODS

Twenty-four participants were assigned of which 12 had normal and 12 had low salivary flow. The study was conducted in 6 in situ experimental phases of 24 h duration: placebo, NaF, SnF₂, F/Sn/Chitosan, F/Arginine, and F/Bioactive Glass. The specimens were previously bleached in vitro. Microhardness (SMH), roughness (Ra), and color analyses (CIELAB and ΔE₀₀) were performed at baseline (T1), after bleaching (T2) and after in situ phase (T3). Scanning electron microscopy (SEM) and the elemental levels (wt%) of Ca, P, and Na and the proportion between Ca and P were determined using an energy-dispersive X-ray spectrometer (EDS) in T3. The SMH and Ra were analyzed by mixed models for repeated measures and Tukey Kramer. The color and Na% were analyzed by split-plot ANOVA and Tukey test. The EDS were analyzed by Mann's Whitney nonparametric, Friedman, and Nemenyi tests (p<0.05).

RESULTS

The dentifrices placebo and NaF in the low flow presented lower SMH and higher Ra in T3 and lower Ca% compared to the same dentifrices in normal flow. For normal flow, SnF₂ resulted in greater SMH. For low flow, SnF₂, F/Sn/Chitosan, and F/Bioactive Glass resulted in higher SMH in T3 and did not differ from T1. F/Bioactive Glass showed lower Ra among the dentifrices evaluated for both salivary flows, whereas SnF₂ showed the highest. F/Bioactive Glass showed a statistically significant difference from placebo for Ca%, P%, Na%. For ΔE^*_ab and ΔE₀₀ (T1×T3), no differences were found for the dentifrices and salivary flows.

CONCLUSION

The low salivary flow had less capacity for remineralization of bleached enamel compared to normal flow. Overall, the dentifrice with bioactive glass had the best performance in bleached enamel under low and normal salivary flow condition.

CLINICAL RELEVANCE

It is recommended to use a bioactive glass-based dentifrice after bleaching to promote tooth enamel recovery for patients with or without impaired salivary flow.

Awareness, knowledge and treatment decisions for erosive tooth wear: A case-based questionnaire among Danish dentists

Objective

To examine the knowledge and experience of erosive tooth wear (ETW) among Danish dental practitioners and, based on two cases, explore their treatment decisions.

Methods

We sent a validated questionnaire electronically to all active members of The Danish Dental Association and The Association of Public Health Dentists in Denmark. The questionnaire had two parts; the first focused on scoring, recordkeeping, knowledge and experience of ETW. The second part presented two patients with different severity of erosive lesions to explore the dentists preventive and restorative treatment decisions.

Results

We received 442 answers from 4,490 potentially eligible dentists in Denmark (response rate 9.8%). The majority (78%) was female and the median age was 44 years. Nearly all respondents (97%) registered ETW in the charts and 49% recorded “always” or “often” the patients' diet history, most commonly with aid of interviews. The respondents perceived the prevalence of ETW to be higher today than 10–15 years ago and male patients (15–25 years) appeared more affected than females. The majority (82%) thought that they usually found the probable cause of the condition with carbonated beverages being the most common factor. The treatment included dietary guidance, soft tooth brushing with non‐abrasive fluoride toothpaste, topical fluoride applications and direct composite restorations.

Conclusion

The majority of Danish dentists taking part of this survey had adopted a minimally invasive approach for the management of erosive tooth wear in young adults. There was however room for improvements in diagnosis, scoring and case documentation.

Stannous Fluoride Effects on Enamel: A Systematic Review

In recent years there has been a lot of talk about toothpastes with a particular chemical compound: stannous fluoride (SnF2). Its presence is currently still highly controversial, as the latter could have negative health effects. The different companies that produce toothpastes express its dosage in ppm. The purpose of this systematic literature review is to analyze all randomized clinical trials in the literature over the last 10 years and to draw clear results on the function of stannous fluoride, for this purpose the authors performed a Mann-Whitney U Test.

MATERIALS

The first analysis of the literature produced a number greater than 800 results, subsequently applying the inclusion and exclusion criteria, and following a manual analysis of the results, 26 manuscripts have been obtained.

RESULTS

From the results analyzed in this review, it could be shown that stannous fluoride does not present important contraindications, if not those commonly reported for fluorine. A meta-analysis on enamel loss has been conducted, it shows that SnF2 products provide better results with a p < 0.05 value.

CONCLUSION

This compound could have significant effects in favor of erosion and recalcification of the enamel, on the biofilm formation, gingival inflammation, and in addition, it could be an important aid in the removal of tooth stains and halitosis.

Effect of black tea and matrix metalloproteinase inhibitors on eroded dentin in situ

Purpose of this in situ study was to evaluate the surface properties of eroded dentin specimens activated with three different matrix metalloproteinase (MMP) inhibitors (chlorhexidine [CHX], fluoride, green tea), black tea, and water. One hundred eighty dentin samples were prepared from extracted third molars and then samples divided into six groups. Ten volunteers were carried three specimens of each group, on acrylic palatal appliances, which were fabricated exactly for them (n = 3). Erosive cycles were done by immersing appliances in cup containing Cola and was followed by rinsing with test solutions. Microhardness values were measured. Surface properties were investigated by atomic force microscopy (AFM). Lowest change in microhardness was shown in fluoride group whereas negative control group (water) had the highest change. There were no statistically significant differences among surface roughness changes (p > .05). The least change in microhardness was seen in the fluoride group (13.05 ± 8.07), while the control group showed the highest change (33.80 ± 12.42) and was statistically significant when compared to other groups (p < .05). Besides lowest depth, values were shown in fluoride group as well. AFM evaluations showed macromolecular deposits on surfaces of fluoride, CHX, and black tea groups. No superior results were detected in CHX + fluoride group and black tea showed similar surface characteristics as green tea. Mouthrinses containing not only green tea but also black tea could be beneficial for patients with exposed dentin surfaces. Catechines and theaflavins in teas could be useful for improving surface quality.

Analytical strategies for clinical studies on dental erosive wear

BACKGROUND

There is a need for analytical techniques for measuring Erosive Tooth Wear (ETW) on natural surfaces in clinical studies. The purpose was to investigate the use of two instruments aimed to assess initial to more advanced stages of ETW.

METHODS

Human premolar enamel samples (2x3mm) (n = 24), were polished flat and mounted in resin cylinders (4 cylinders, 6 samples in each). Part 1: Baseline analyses by White Light Interferometer (WLI), Surface Reflection Intensity (SRI: TableTop and OptiPen) and Surface Hardness (SH). Erosion (1% citric acid (pH 3.6) for 1, 2, 4, 6, 8, 10 min. SRI and SH analyses after every erosion episode and by WLI after 10 min. New indentations were made and enamel loss; was measured by change in indentation depths from toothbrush abrasion (200 g, 60 strokes, 30 s). Another series of 2 × 5 min erosion (totally15 min and 20 min) was analysed with SH and SRI after each erosion, and by WLI (on samples and impressions of samples) after 20 min. Part 2 investigated WLI performance in the interface where initial erosion increases in severity and substance loss occurs. The samples were repolished. Baseline analyses by WLI, SRI (TableTop and OptiPen) and SH. Four cylinders were etched for 1, 2, 4, 8 min respectively and analysed by SRI, SH on samples, and WLI on samples and impressions).

RESULTS

Part1: SRI decreased from baseline to ~ 6 min etch and increased slightly after abrasion, the two devices correlated well (ICC 0.98 p < 0.001, Spearmans rs 0.91 p < 0.001). SH decreased nearly linearly to 10 min etch, but increased distinctly after abrasion. Mean enamel loss from abrasion alone was 0.2 μm (change in indentation depths). After 10 min etch, it was 0.27 μm (WLI) and after 20 min etch, it was 2.2 μm measured on samples vs 2.4 μm on impressions of samples (7% higher). Part 2: From baseline to 8 min etch; SRI and SH decreased whereas WLI presented increasing etch depths.

CONCLUSIONS

With some adjustments, the use of SRI and WLI in combination seems to be a promising strategy for monitoring ETW in clinical studies.

Opinions and Treatment Decisions for Dental Erosive Wear: A Questionnaire Survey among Icelandic Dentists

Dental erosive wear (DEW) is common among children and adolescents, and a survey of Icelandic children showed that 30.7% of 15-year-olds were diagnosed with the condition. Objective. To gain knowledge about dental practitioners' experiences, opinions, and treatment decisions. Materials and Methods. A precoded questionnaire, previously used among Norwegian dentists, was sent electronically to all dentists in Iceland (n = 341). Results. The response rate was 64.2%, and 58% of dentists were male. More than half of the clinicians (54%) thought that prevalence had increased the last 10-15 years, and 67% reported it to be more common in male. Most (96%) recorded presence of DEW, but only 4% used a detailed scoring system. Lesions were mostly on occlusal surfaces of first mandibular molars (73%), on palatal in upper anterior teeth (61%), and on occlusal of maxillary first molars (36%). Most dentists (74%) reported a probable cause, e.g., high consumption of carbonated beverages (98%), acidic juices (68%), sport drinks (58%), reflux (54%), and eating disorders (20%). Dietary history was often recorded by 38%, and 65% never measured saliva. Most of the dentists (88%) treated patients themselves, and half of them preferred prevention with high fluoride and resin sealants. While some dentists wanted to restore teeth more invasively, most considered to restore with a filling. Conclusion. Icelandic dentists seem to be well educated for diagnosis and treatment of dental erosion, and dentists are aware of a minimally invasive approach. Clinical Significance. It is challenging for dentists to make the best treatment decision for patients with DEW, both in a short perspective and long perspective. At present, little is known about their knowledge and treatment approach, and there is no standard treatment which can be recommended. Therefore, the present study investigated dental practitioners' treatment decisions, as well as knowledge, experiences, and awareness of DEW.

New animal model of extrinsic dental erosion-Erosive effect on the mouse molar teeth

OBJECTIVE

Consumption of acidic food and drinks is considered as important risk factor for development of dental erosion. There are several in vitro and in situ studies focusing on the risk indicators and preventive treatment, however, the need for a standardized animal model has been emphasised for many years. The aim was to establish an animal model of extrinsic dental erosion, which may serve as a standard for future studies to improve our understanding of the erosion.

DESIGN

Two acidic drinks, sports drink and cola drink, were given to young mice for six weeks. Experimental and control (water) molars and incisors were dissected out and observed by scanning electron microscopy (SEM). Mandibular first molars were subsequently ground transversely and observed again by SEM. The tooth height and enamel thickness were measured on the SEM images.

RESULTS

The lingual surface of the mandibular molars was most eroded after consumption of acidic drinks. The cola drink exhibited higher erosive effect on mandibular molars compared to sports drink. The lingual tooth height, compared to control, was about 34% and 18% lower in the cola drink and sports drink molars, respectively. Compared to the control molars, the lingual enamel was about 23% thinner in the sports drink molars and totally eroded on the certain lingual areas of the cola drink molars.

CONCLUSIONS

This new animal model of extrinsic dental erosion and the presented method with ground molars observed in SEM are suitable for further studies, which will gain deeper insights into the erosive disease.

Mechanism of Action of TiF4 on Dental Enamel Surface: SEM/EDX, KOH-Soluble F, and X-Ray Diffraction Analysis

This in vitro study aimed to evaluate the action of TiF4 on sound and carious bovine and human enamel. Sound (S) and pre-demineralised (DE) bovine and human (primary and permanent) enamel samples were treated with TiF4 (pH 1.0) or NaF varnishes (pH 5.0), containing 0.95, 1.95, or 2.45% F for 12 h. The enamel surfaces were analysed using SEM-EDX (scanning electron microscopy/energy-dispersive X-ray spectroscopy) (n = 10, 5 S and 5 DE) and KOH-soluble fluoride was quantified (n = 20, 10 S and 10 DE). Hydroxyapatite powder produced by precipitation method was treated with the corresponding fluoride solutions for 1 min (n = 2). The formed compounds were detected using X-ray diffraction (XRD). All TiF4 varnishes produced a coating layer rich in Ti and F on all types of enamel surface, with micro-cracks in its extension. TiF4 (1.95 and 2.45% F) provided higher fluoride deposition than NaF, especially for bovine enamel (p < 0.0001). It also induced a higher fluoride deposition on DE samples compared to S samples (p < 0.0001), except for primary enamel. The Ti content was higher for bovine and human primary enamel than human permanent enamel, with some differences between S and DE. The XRD analysis showed that TiF4 induced the formation of new compounds such as CaF2, TiO2, and Ti(HPO4)2·H2O. In conclusion, TiF4 (>0.95% F) interacts better, when compared to NaF, with bovine and human primary enamel than with human permanent enamel. TiF4 provoked higher F deposition compared to NaF. Carious enamel showed higher F uptake than sound enamel by TiF4 application, while Ti uptake was dependent on the enamel condition and origin.

In situ evaluation of fluoride-, stannous- and polyphosphate-containing solutions against enamel erosion

OBJECTIVE

To evaluate the anti-erosive effect of solutions containing sodium fluoride (F: 225ppm of fluoride), sodium fluoride+stannous chloride (F+Sn: 225ppm of fluoride+800ppm of stannous), sodium fluoride+stannous chloride+sodium linear polyphosphate (F+Sn+LPP: 225ppm of fluoride+800ppm of stannous+2% of sodium linear polyphosphate), and deionized water (C: control), using a four-phase, single-blind, crossover in situ clinical trial.

METHODS

In each phase, 12 volunteers wore appliances containing 4 enamel specimens, which were submitted to a 5-day erosion-remineralization phase that consisted of 2h of salivary pellicle formation with the appliance in situ, followed by 2min extra-oral immersion in 1% citric acid (pH 2.4), 6x/day, with 90min of exposure to saliva in situ between the challenges. Treatment with the test solutions was performed extra-orally for 2 min, 2x/day. At the end of the experiment, surface loss (SL, in μm) was evaluated by optical profilometry. Data were analyzed using ANOVA and Tukey tests (α=0.05). The surface of additional specimens was evaluated by x-ray diffraction after treatments (n=3).

RESULTS

C (mean SL±standard-deviation: 5.97±1.70) and F (5.36±1.59) showed the highest SL, with no significant difference between them (p>0.05). F+Sn (2.68±1.62) and F+Sn+LPP (2.10±0.95) did not differ from each other (p>0.05), but presented lower SL than the other groups (P<0.05). Apatite and stannous deposits on specimen surfaces were identified in the x-ray analysis for F+Sn and F+Sn+LPP.

CONCLUSIONS

Sodium fluoride solution exhibited no significant anti-erosive effect. The combination between sodium fluoride and stannous chloride reduced enamel erosion, irrespective of the presence of linear sodium polyphosphate.

CLINICAL SIGNIFICANCE

Under highly erosive conditions, sodium fluoride rinse may not be a suitable alternative to prevent enamel erosion. A rinse containing sodium fluoride and stannous chloride was shown to be a better treatment option, which was not further improved by addition of the sodium linear polyphosphate.

Efficacy of Stannous Ions on Enamel Demineralization under Normal and Hyposalivatory Conditions: A Controlled Randomized in situ Pilot Trial

The study aim was to investigate the effect of antierosive agents on enamel under normal and hyposalivatory conditions. This double-blind crossover in situ pilot study evaluated 4 toothpastes: placebo (0 ppm F), sodium fluoride (NaF, 1,450 ppm), stannous/sodium fluoride (SnF/NaF, 1,450 ppm F-, 1,090 ppm Sn2+), and sodium fluoride, stannous chloride and chitosan (NaF/Sn/Ch, 1,450 ppm F-, 3,500 ppm Sn2+, 0.5% Ch). Twenty participants were assigned to 2 groups (n = 10 each): normal and low salivary flow. Participants wore palatal appliances holding 4 bovine enamel specimens previously eroded in vitro (D1) for 20 min prior to an in situ phase after which they were eroded again (D2). Surface microhardness was determined at baseline (BL), after D1, in situ phase and D2 to assess hardness loss (%SMH), residual hardness loss (%RHL) and erosion resistance (%RER). Additional specimens were evaluated by scanning electron microscopy after the in situ phase. ANOVA and a factorial analysis for between-subject effects were performed. Sn-based toothpastes showed the best effects (p < 0.05). Under normal flow, SnF/NaF showed higher efficacy, with a significant difference compared to NaF/Sn/Ch, NaF, and placebo (p < 0.05). Under low flow, SnF/NaF and NaF/Sn/Ch were comparable (p > 0.05); NaF and placebo were statistically similar. Comparing salivary conditions, there were significant differences for SnF/NaF for %SMH after the in situ phase (%SMHtotal)), %RHL and for all toothpastes in case of %RER. Factorial analysis revealed interactions between toothpaste and saliva flow for %SMHtotal and %RHL. Salivary flow can influence the efficacy of the antierosive toothpastes; however, Sn2+ preparations show even under low salivary flow conditions the highest efficacy in the prevention of enamel erosion.

Effect of a Single Application of TiF4 Varnish versus Daily Use of a Low-Concentrated TiF4/NaF Solution on Tooth Erosion Prevention in vitro

This study investigated the isolated and combined effect of a single application of TiF4 or NaF varnish versus daily use of a solution containing a low concentration of TiF4/NaF against tooth erosion in vitro. A total of 90 bovine enamel and 108 root dentin samples were treated as follows: control (no treatment), solution containing TiF4/NaF (500 ppm F-, pH 4.4), NaF varnish (24,500 ppm F-, pH 5.0), TiF4 varnish (24,500 ppm F-, pH 1.0), TiF4 varnish + solution, and NaF varnish + solution. The erosive challenges were performed 4 × 90s/day (0.1% citric acid, pH 2.5) and, between them, the samples were immersed in artificial saliva. The tooth loss was measured using contact profilometry (after 7 days for dentin and after 7, 10, and 14 days for enamel). All treatments were effective in reducing tooth loss, except NaF varnish for enamel on day 7 (p < 0.0001). TiF4/NaF solution and TiF4 varnish did not differ with respect to enamel loss for 10 days; thereafter, TiF4 varnish lost its protective effect compared to TiF4/NaF solution. The combination of vehicles was more effective in reducing enamel loss than both varnishes on their own but not compared to the solution. For dentin, TiF4 varnish was more effective than NaF varnish, while TiF4/NaF solution and NaF varnish were similar. The combination of vehicles improved the protective effect only when compared to NaF varnish on its own (p < 0.0001). Both types of TiF4 applications, isolated or combined, were effective against tooth erosion, but some differences in their performance were seen between enamel and dentin.

The Susceptibility to Dental Erosion Differs among Individuals

Studies of wine tasters and patients with self-induced vomiting have revealed that 30-50% of individuals at high risk do not develop erosive lesions. The aim was to investigate this apparent individual susceptibility to enamel erosion. Two enamel specimens were made from each of 3 premolars from 8 persons (donors). Six acrylic mouth appliances were worn by 6 volunteers (carriers). One specimen from each donor was mounted on each appliance. The carriers wore the appliances for 9 days. The appliances were immersed in 0.01 M HCl for 3 min twice per day to imitate a vomiting/reflux situation. The enamel specimens were analysed by a white-light interferometer to measure enamel loss (in micrometres). The enamel loss varied significantly both between the donor teeth (p = 0.009) and the carriers (p = 0.004). The lesion in the specimen with the largest amount of enamel loss was 4 times as deep as in the specimen with the lowest. In 1 carrier, all specimens displayed enamel loss above the mean, including the specimen from the donor with the most resistant enamel. The variation in susceptibility to erosion among individuals appears to be influenced both by the sustainability of the enamel and by factors in the oral environment. This could explain the variation in prevalence and severity of dental erosions among patients exposed to similar acidic challenges. The results suggest that for certain individuals, only minimal acidic challenges may be sufficient to cause damage to the teeth, while others may never develop dental erosions despite extensive exposure to acid.

Protective effect of experimental mouthrinses containing NaF and TiF4 on dentin erosive loss in vitro

Objective

This in vitro study assessed the anti-erosive effect of experimental mouthrinses containing TiF₄ and NaF on dentin erosive loss.

Material and Methods

Bovine dentin specimens were randomly allocated into the groups (n=15): 1) SnCl₂/NaF/AmF (Erosion Protection^®/GABA, pH 4.5, positive control); 2) experimental solution with 0.0815% TiF₄ (pH 2.5); 3) 0.105% NaF (pH 4.5); 4) 0.042% NaF+0.049% TiF₄ (pH 4.4); 5) 0.063% NaF+0.036% TiF₄ (pH 4.5); 6) no treatment (negative control). Each specimen was cyclically demineralized (Sprite Zero, pH 2.6, 4x90 s/day) and exposed to artificial saliva between the erosive challenges for 7 days. The treatment with the fluoride solutions was done 2x60 s/day, immediately after the first and the last erosive challenges of the day. Dentin erosive loss was measured by profilometry (μm). The data were analyzed using Kruskal Wallis/Dunn tests (p<0.05).

Results

Mouthrinses containing TiF₄ or Sn/F were able to show some protective effect against dentin erosive loss compared to negative control. The best anti-erosive effect was found for experimental solution containing 0.0815% TiF₄ (100% reduction in dentin loss), followed by 0.042% NaF+0.049% TiF⁴ (58.3%), SnCl₂/NaF/AmF (52%) and 0.063% NaF+0.036% TiF₄ (40%). NaF solution (13.3%) did not significantly differ from control.

Conclusion

The daily application of experimental mouthrinse containing TiF₄ and NaF has the ability to reduce dentin erosion, as well as Erosion Protection^® and TiF₄ alone.

Influence of Toothbrushing on the Antierosive Effect of Film-Forming Agents

This study evaluated the influence of toothbrushing on the antierosive effect of solutions containing sodium fluoride (225 ppm/F), stannous chloride (800 ppm/Sn), sodium linear polyphosphate (2%/LPP), and their combinations, and deionized water as negative control (C). Solutions were tested in a 5-day erosion-remineralization-abrasion cycling model, using enamel and dentin specimens (n = 8). Erosion was performed 6 times/day for 5 min, exposure to the test solutions 3 times/day for 2min, and toothbrushing (or not) with toothpaste slurry 2 times/day for 2 min (45 strokes). Surface loss (SL) was determined by noncontact profilometry. Data were analyzed using three-way ANOVA (α = 0.05). Brushing caused more SL than no brushing for enamel (mean ± SD, in micrometers: 52.7 ± 6.6 and 33.0 ± 4.5, respectively), but not for dentin (28.2 ± 1.9 and 26.6 ± 1.8, respectively). For enamel without brushing, F+LPP+Sn showed the lowest SL (23.8 ± 3.4), followed by F+Sn (30.6 ± 4.9) and F+LPP (31.7 ± 1.7), which did not differ from each other. No differences were found between the other groups and C (37.8 ± 2.1). When brushing, F+LPP+Sn exhibited the lowest SL (36.7 ± 2.4), not differing from F+LPP (39.1 ± 1.8). F, F+Sn and LPP+Sn were similar (46.7 ± 2.9, 42.1 ± 2.8 and 45.3 ± 4.6, respectively) and better than C (52.7 ± 4.3). Sn (55.0 ± 2.4) and LPP (51.0 ± 4.3) did not differ from C. For dentin, neither groups differed from C, regardless of brushing. In conclusion, toothbrushing did not affect the antierosive effect of F+Sn, F+LPP and F+LPP+Sn on enamel, although overall it led to more erosion than nonbrushing. F and LPP+Sn showed a protective effect only under brushing conditions, whereas Sn and LPP did not exhibit any protection. For dentin, neither toothbrushing nor the test solutions influenced the development of erosion.

Combined Tin-Containing Fluoride Solution and CO2 Laser Treatment Reduces Enamel Erosion in vitro

The aim of this in vitro study was to evaluate the effect of combined CO2 laser and tin-containing fluoride treatment on the formation and progression of enamel erosive lesions. Ninety-six human enamel samples were obtained, stored in thymol solution and, after surface polishing, randomly divided into 6 different surface treatment groups (n = 16 in each group) as follows: no treatment, control (C); one CO2 laser irradiation (L1); two CO2 laser irradiations (L2); daily application of fluoride solution (F); combined daily fluoride solution + one CO2 laser irradiation (L1F), and combined daily fluoride solution + two CO2 laser irradiations (L2F). Laser irradiation was performed at 0.3 J/cm2 (5 µs/226 Hz/10.6 µm) on day 1 (L1) and day 6 (L2). The fluoride solution contained AmF/NaF (500 ppm F), and SnCl2 (800 ppm Sn) at pH 4.5. After surface treatment the samples were submitted to an erosive cycling over 10 days, including immersion in citric acid (2 min/0.05 M/pH = 2.3) 6 times daily and storage in remineralization solution (≥1 h) between erosive attacks. At the end of each cycling day, the enamel surface loss (micrometers) was measured using a 3D laser profilometer. Data were statistically analyzed by means of a 2-level mixed effects model and linear contrasts (α = 0.05). Group F (-3.3 ± 2.0 µm) showed significantly lower enamel surface loss than groups C (-27.22 ± 4.1 µm), L1 (-18.3 ± 4.4 µm) and L2 (-16.3 ± 5.3 µm) but higher than L1F (-1.0 ± 4.4 µm) and L2F (1.4 ± 3.2 µm, p < 0.05). Under the conditions of this in vitro study, the tin-containing fluoride solution caused 88% reduction of enamel surface loss, while its combination with CO2 laser irradiation at 0.3 J/cm2 hampered erosive loss almost completely.

The Future of Fluorides and Other Protective Agents in Erosion Prevention

The effectiveness of fluoride in caries prevention has been convincingly proven. In recent years, researchers have investigated the preventive effects of different fluoride formulations on erosive tooth wear with positive results, but their action on caries and erosion prevention must be based on different requirements, because there is no sheltered area in the erosive process as there is in the subsurface carious lesions. Thus, any protective mechanism from fluoride concerning erosion is limited to the surface or the near surface layer of enamel. However, reports on other protective agents show superior preventive results. The mechanism of action of tin-containing products is related to tin deposition onto the tooth surface, as well as the incorporation of tin into the near-surface layer of enamel. These tin-rich deposits are less susceptible to dissolution and may result in enhanced protection of the underlying tooth. Titanium tetrafluoride forms a protective layer on the tooth surface. It is believed that this layer is made up of hydrated hydrogen titanium phosphate. Products containing phosphates and/or proteins may adsorb either to the pellicle, rendering it more protective against demineralization, or directly to the dental hard tissue, probably competing with H+ at specific sites on the tooth surface. Other substances may further enhance precipitation of calcium phosphates on the enamel surface, protecting it from additional acid impacts. Hence, the future of fluoride alone in erosion prevention looks grim, but the combination of fluoride with protective agents, such as polyvalent metal ions and some polymers, has much brighter prospects.

May caries-preventive fluoride regimes have an effect on dental erosive wear? An in situ study

OBJECTIVE

High and low concentration NaF regimes have shown caries protective properties, but the preventive effect against erosive/abrasive wear is unclear. AIM. To measure the inhibiting effect on enamel wear of low and highly concentrated sodium fluoride (NaF) toothpastes and a stannous (SnF2) fluoride gel in a single-blind, randomized in situ study, using a White Light Interferometer.

MATERIALS AND METHODS

Sixteen human molars were each divided into four specimens, mounted on acrylic mouth appliances and worn by eight volunteers for 9 days. Experimental procedures were performed in the laboratory. The enamel specimens were brushed every day with fluoride-free toothpaste. Treatments; group 1: no fluoride treatment (control), group 2: SnF2 gel 2500 ppm F (5 min) every third day, group 3: NaF toothpaste 5000 ppm F 5 min every third day and 2 min the other days, group 4: NaF toothpaste 1450 ppm F (2 min) every day. In order to mimic gastric reflux/vomiting, the specimens were etched with 0.01 M HCl for 2 min twice a day.

RESULTS

The mean step height (µm) for the control specimens was -32.9 (SD = 6.8). The mean values for the other groups were -22.2 (SD = 8.4) (group 2), -30.8 (SD = 7.8) (group 3) and -31.4 (SD = 7.7) (group 4). Compared with the control, the SnF2 treated specimens showed significantly lower wear. The NaF toothpastes gave no significant protective effect.

CONCLUSIONS

Application of SnF2 gel every third day gave protection against erosive-abrasive challenges. Daily application of both low concentration and high concentration NaF toothpaste provided no protection.

The protective effect of SnF2 containing toothpastes and solution on enamel surfaces subjected to erosion and abrasion in situ

BACKGROUND

Stannous fluoride solutions have shown promising protective effect against erosion/abrasion, but the effect of SnF2 toothpastes is uncertain.

AIM

The aim of the study was to test the inhibiting effect of two SnF2 toothpastes and a SnF2 solution against erosive/abrasive wear in a single-blind, randomised in situ study, using a white light interferometer.

METHODS

Sixteen human molars were each divided into four specimens, mounted on mouth appliances and worn by 8 volunteers for 9 days. Specimens were brushed with toothpaste twice each day for 30 s either with fluoride-free toothpaste or toothpastes including SnF2. Toothpaste was left on the surface for 90 additional seconds. Group 1, fluoride-free toothpaste; Group 2, toothpaste A (0.4% SnF2, Solidox); Group 3, toothpaste B (0.454 % SnF2, Oral-B(®)); Group 4, brushed with fluoride-free toothpaste (30 s) and treated for 2 min with a 0.4 % SnF2 solution (1,000 ppm F). To mimic gastric reflux/vomit, specimens were etched for 2 min twice a day (0.01 M HCl). Procedures were performed extra-orally.

RESULTS

The mean enamel wear (in μm) for the control specimens was: -29.2 ± SD 10.5; for group 2 -14.5 SD ± 9.3; for group 3 -33.3 SD ± 7.4, and for group 4 +0.4 SD ± 1.3. The specimens treated with SnF2 solution and toothpaste A showed significantly lower enamel wear than the control group. Toothpaste B gave no significant reduction in enamel wear.

CONCLUSIONS

The SnF2 solution fully protected the enamel surface against erosive and abrasive challenges. The SnF2 toothpaste A (Solidox) showed less, but significant protection of the enamel, while no statistically significant protection was demonstrated by SnF2 toothpaste B (Oral-B(®) Pro-Expert).