L’érosion Et L’hypersensibilité

Dental erosion is prevalent in children and adults globally, with some researchers finding it present in approximately half of adolescents (Al-Dlaigan et al. 2001; McGuire et al. 2009). Estimated prevalence in some locations can be found in Figure 6.

Erosion Research Summaries

The Protective Effects of Toothpaste Against Erosion By Orange Juice: Studies in Situ and in Vitro

Enamel Protection vs. Abrasivity - A Study of Relevance

A Randomized Clinical Trial to Measure the Erosion Protection Benefits of a Stannous Fluoride Dentifrice versus a Triclosan/Copolymer Dentifrice

A Randomized Clinical Trial to Measure the Erosion Protection Benefits of a Stabilized Stannous Fluoride Dentifrice versus a Control Dentifrice

Stannous Fluoride Clinical Significance Erosion

Dental erosion occurs primarily due to the excessive presence of non-bacterial extrinsic acids (especially dietary acids such as acidic drinks), as well as intrinsic gastric acid associated with gastroesophageal reflux disease (GERD) and bulimia (Moazzez et al. 2004; Bouqot & Seime 1997). Dental erosion involves the demineralization and softening of the tooth surface, which once softened, is highly susceptible to abrasion and attrition (Figure 7). A diagnosis of erosion can be made based on the pattern of surface loss of enamel and/or dentin (Figures 8a,b)

Unlike dental caries where demineralization is initially mainly subsurface and is also reversible in its early stages, dental erosion involves repeated demineralization of the surface with subsequent surface loss and this process is irreversible (Figures 9a, b).

Mechanism of action for anti-erosion effect of stabilized stannous fluoride

The deposition of stannous ions at the tooth surface helps protect it against dental erosion (Faller & Eversole 2014):

• Deposition of stannous fluorophosphate or stannous oxide layers onto enamel surfaces has been reported after stannous fluoride treatment.

• Deposition occurs primarily as a result of the attachment of the stannous ion to free phosphate sites on the surface of enamel.

• Stannous forms a protective layer on the surface that is highly resistant to acids.

A recent in vitro study compared the ability of various fluoride toothpastes to form a protective barrier layer (Faller & Eversole 2014). The toothpastes evaluated included 1,100 ppm stannous fluoride, 1,100 ppm sodium fluoride, 1,000 ppm sodium monofluorophosphate and 1,400 ppm amine fluoride. The study involved exposing etched samples to toothpaste-saliva slurries, rinsing them, and then exposing them to 2% alizarin Red-S. Dye deposition was assessed using a 5-point scale, with 0 being no dye deposition and 4 being complete dye coverage. A low score indicates a barrier layer is present, preventing the deposition of dye. The stannous fluoride toothpaste had the lowest score, 0.25. At the other extreme, amine fluoride resulted in a score of 3.7 (Figure 10). This in vitro test confirmed the ability of stannous to form a protective barrier layer, and demonstrated that stannous fluoride is a preferred fluoride for delivering an enamel protection benefit via a barrier mechanism to erosive acids.

Figure 10. Degree of dye deposition on enamel samples following exposure to toothpaste slurry followed by dye

The following study summaries represent a sample of research demonstrating the benefits of stabilized stannous fluoride dentifrice for protection against acid erosion. In addition, an independent consensus statement by the European Federation of Conservative Dentistry found “oral hygiene products, such as toothpastes or mouth rinses, containing stannous fluoride or stannous chloride have the potential to slow the progression of erosive tooth wear.” The authors found data are limited for other products. (Carvalho et al. 2015)

Reference: Hooper SM, Newcombe RG, Faller R, Eversole S, Addy M, West NX. J Dent. 2007 Jun;35(6):476-81. Epub 2007 Feb 27

Objective

Consumption of soft drinks, fruit juices and sport drinks has increased dramatically in the UK, the US, and elsewhere. Previous studies have demonstrated the erosive nature of these acidic soft drinks. The objective of this study was to determine the protective effects of experimental stannous fluoride-based toothpaste, containing sodium hexametaphosphate, against an erosive challenge (orange juice) on tooth enamel.

Materials And Methods

• This research included a 15-day challenge in vitro study and a 15-day in situ single blind, 3-way, crossover clinical trial.

• The following formulations were tested:

  1. experimental stannous fluoride dentifrice with sodium hexametaphosphate for cosmetic benefits (P&G);

  2. a benchmark sodium fluoride dentifrice (Cres^® Cavity Protection, P&G); and

  3. negative control, water.

• Flat, polished human enamel samples with a surface profile of +/-0.1μm, were exposed to the three regimens.

• The orange juice used as erosion challenge had a pH 3.8.

• 15 volunteers wore an intra-oral appliance with 2 specimens of enamel embedded in the mid-palatal region from 9:00 to 17:00 (removed for 1 hour at lunchtime). Whilst appliances were in place, no food or drink other than water and the designated orange juice were consumed. Volunteers were asked to rinse with a toothpaste slurry or water at 9:00 and 13:00 followed by consumption of 250 ml orange juice 1 and 3 h later.

• Subjects were treated with one study formulation for 5 days followed by two nontreatment days.

• A profilometer was used to measure depths of the resulting eroded areas at days 5, 10 and 15.

Results

There was significantly more erosive damage on the specimens exposed to the benchmark toothpaste (NaF) and negative control (water) compared to the test stannous fluoride toothpaste in both the in situ (Figure 1) and in vitro (Figure 2) studies.

* mean value based on duplicate determinations of two enamel specimens

Reference: Faller RV, Eversole SL, Tzeghai G. J Dent Res. 2009;88 (Spec Iss A): Abstract 3368.

Objective

Dentifrices with RDA< 250 are considered safe for daily use. Some researchers believe products with low RDA may be less aggressive on erosively softened enamel. Others believe that once softened, erosively challenged enamel will be removed by any friction, even by the tongue. This research was conducted to determine the primary driver of enamel protection benefits: is abrasivity or fluoride (F) salt the more important factor?

Materials And Methods

• Cores of extracted, human enamel were cleaned, ground and polished to provide a virgin enamel surface, soaked in human saliva (pellicle formation), and treated in a 1:3 (product:saliva) slurry of toothpaste representing a range of actives/RDA values [SnF₂(RDA~150), NaF#1(RDA~100), NaF#2(RDA~50)].

• Specimens were subjected to dynamic pH cycling conditions including exposure to multiple 1% citric acid challenges over a 5-day period.

• Treatment slurries and saliva baths were constantly stirred to ensure a steady flow,representing repetitive challenges to the enamel by a combination of common dietary acid and abrasive elements.

• The study was run in duplicate to test model reproducibility. Results were averaged.

Results

• The product with RDA~150 provided significant (P=0.05, ANOVA) protection against damage (8.0μm of surface loss), with lower RDA products (RDA~50 or 100) showing no significant differences between them in their ability to protect enamel against damage (27.3 and 25.4μm of surface loss, respectively). See Table and Figure.

• It is important to note the active F species in the RDA~150 formulation was SnF₂. SnF₂

   provides significant protection against erosive acid damage by forming a protective barrier layer on the enamel surface, protecting against external challenges.

• The model is reproducible.

Reference: XY Zhao¹, T He², Y He², C Cheng², HJ Chen².

¹Fourth Military Medical University, Xi’an, PR China; ²Procter & Gamble.

The experimental stabilized stannous fluoride (SnF2) dentifrice provided 26.9% greater erosion protection relative to the control dentifrice at Day 10 (P<0.03).

Objective

To compare the enamel protection efficacy of a stabilized stannous fluoride dentifrice and a marketed control dentifrice in a 10-day in situ erosion model.

Study Design

• A single center, double-blind, randomized, 2-treatment, and 3-period crossover clinical study was conducted involving healthy adults.

• Subjects presented for 3 study periods and were randomized to treatment sequences, receiving one of the two marketed dentifrice products each period:

1. Experimental 0.454% stabilized SnF² dentifrice (Crest^® PRO-HEALTH^™ Clean Mint [Smooth Formula], Procter & Gamble)

2. Sodium fluoride dentifrice with potassium nitrate marketed for protection from the effects of acid erosion (Sensodyne^® Pronamel®, GlaxoSmithKline)

• Each study period was comprised of 10 treatment days. On each treatment day, subjects brushed their teeth at home in their usual manner, using a non-treatment toothpaste and a regular, soft manual toothbrush supplied at the screening visit.

• Subjects then attended the clinical trials unit where they collected their lower palatal intraoral appliance fitted with 8 enamel samples and placed it in their mouth. Subjects wore the appliance for approximately 6 hours total over the course of each study day. While wearing the appliance, subjects brushed their lingual teeth for 30 seconds, and swished with their assigned treatment toothpaste slurry for 90 seconds twice a day under the supervision of clinic staff.

• The erosive challenge occurred with the appliance in the mouth. The subjects were required to sip 25mL of orange juice over a timed minute, swishing it around their mouth, then spitting out. This was repeated 10 times so that a total of 250mL of orange juice was exposed to the enamel samples over a 10 minute period. The erosive challenge occurred a total of four times on each treatment day.

• On Day 10, the enamel samples were measured for tissue loss using a calibrated contact surface profilometer. Measurements were taken at baseline, prior to the start of the study, and at the end of treatment Day 10. Fresh enamel samples were placed in the intra-oral appliance at the beginning of each treatment period.

• Statistical analyses utilized a general linear mixed model with period and treatment as fixed effects and subject as a random effect.

*Lussi A. Int Dent J 2014; 64 (Suppl 1): 2-3.

Case Studies

ÉTUDES CLINIQUES – OFFERTES EN ANGLAIS UNIQUEMENT

ÉDUCATION DU PATIENT

Hypersensitivity Research Summaries

Efficacy and Safety of a Novel Stabilized Stannous Fluoride and Dentifrice for Dentinal Hypersensitivity

Desensitizing Effect of a Stabilized Stannous Fluoride Dentrifice

A Clinical Trial Evaluating Immediate Sensitivity Relief of a 0.454% Stannous Fluoride Dentifrice

A Randomized Clinical Trial Evaluating a 2-step Stannous Fluoride Dentifrice and Whitening Gel System Versus a Potassium Nitrate Dentifrice for Sensitivity Relief

Clinical Significance: Hypersensitivity

Mechanism of action of stabilized stannous fluoride dentifrice

Early treatments using solutions and later gels demonstrated the desensitizing effect of stannous fluoride. The dentinal tubules are occluded by precipitated stannous salts, inhibiting fluid movement within the tubules and thereby preventing nerve stimulation and pain (Figures 13, 14; Miller et al. 1994; Thrash et al. 1995).

Figure 13. Dentinal tubule occlusion: Note the effective occlusion of dentinal tubules with stabilized stannous fluoride dentifrice (SEM x2000)

Figure 14. Pre-and post-brushing SEMs: pre-and post-treatment with open and occluded dentinal tubules Courtesy of Cosmetics & Toiletries

Hypersensitivity Research Summaries

The following study summaries represent a sample of research demonstrating the benefits of stabilized stannous fluoride dentifrice for the reduction of hypersensitivity.

Efficacy And Safety Of A Novel Stabilized Stannous Fluoride And Dentifrice For Dentinal Hypersensitivity

Reference: Schiff T, He T, Sagel L, et al. J Contemp Dent Pract. 2006;7(2):1-8.

Conclusion

Crest^® PRO-HEALTH^™ provided statistically significant reductions in dentinal hypersensitivity at 4 and 8 weeks compared to the sodium fluoride control dentifrice.

Objective

To compare the efficacy of Crest^® PRO-HEALTH^™ vs a negative control dentifrice in the reduction of dentinal hypersensitivity over an 8-week period.

MATERIALS AND METHODS

• Crest^® PRO-HEALTH^™ (a novel 0.454% stabilized stannous fluoride dentifrice with sodium hexametaphosphate for cosmetic benefits) was compared to a negative control dentifrice containing 0.243% sodium fluoride (Crest^® Cavity Protection).

• Study subjects were 90 generally healthy adults with moderate dentinal hypersensitivity: minimum of 2 bicuspid or cuspid teeth with sensitivity criteria of Yeaple Probe Index score = 10 g and Schiff Air Sensitivity Scale score of >1.

• Experimental 0.454% stabilized SnF2 dentifrice (Crest® PRO-HEALTH^™ Clean Mint [Smooth Formula], Procter & Gamble)

• Tooth sensitivity was measured by tactile examination using the Yeaple probe (only teeth responding positively to 10 g and rechallenge at 10 g were evaluated) and cold air using the Schiff Air Index (teeth responding to air stimulus were evaluated).

• Oral soft tissue examinations were performed.

• Subjects were randomized to either the stabilized stannous fluoride dentifrice or the control dentifrice.

• Subjects brushed twice daily with their assigned dentifrice using a manual soft toothbrush for 8 weeks.

• Subjects were assessed again for sensitivity and safety at weeks 4 and 8.

Results

• Data were analyzed for all 90 subjects (45 in each treatment group).

• Schiff Air Index scores were statistically significantly lower for the stabilized stannous fluoride group than the sodium fluoride control group at both weeks 4 and 8 (P<0.0001).

• Compared to the sodium fluoride control group, the stannous fluoride group showed a 33% lower Schiff Air Index score (adjusted mean) than the sodium fluoride control group at week 4 and a 44% lower score at week 8.

• Yeaple Probe Index scores were statistically significantly higher for the stabilized stannous fluoride group than the sodium fluoride control group at both weeks 4 and 8 (P<0.0001).

• Compared to the sodium fluoride control group, the stabilized stannous fluoride group had a mean Yeaple Probe Index score 14 units higher (representing a mean desensitizing improvement of 114% greater) than that of the sodium fluoride control group at week 4, and 11 units higher (representing a mean desensitizing improvement of 71% greater) at week 8.

• No adverse events were reported or observed.

Lower Schiff Air Index scores indicate less tooth sensitivity.

DESENSITIZING EFFECT OF A STABILIZED STANNOUS FLUORIDE DENTIFRICE

Full text available in the Research Database at www.dentalcare.com

Reference: Schiff T, Saletta L, Baker RA, et al. Compend Contin Educ Dent. 2005;26(9 suppl 1):35-40.

Conclusion

Crest^® PRO-HEALTH^™ showed a clinically and statistically significant decrease in hypersensitivity compared to a negative control dentifrice.

Objective

To evaluate the desensitizing properties of Crest^® PRO-HEALTH^™ compared to a negative control dentifrice.

Materials And Methods

• Crest^® PRO-HEALTH^™ (0.454% stabilized stannous fluoride dentifrice with sodium hexametaphosphate for cosmetic benefits) was compared to a marketed negative control dentifrice containing 0.243% sodium fluoride (Crest^® Cavity Protection).

• Study subjects were adults with a minimum of 2 bicuspid/cuspid teeth with sensitivity criteria of Yeaple Probe Index = 10 g and Schiff Air Sensitivity Scale score of >1.

• Experimental 0.454% stabilized SnF2 dentifrice (Crest^® PRO-HEALTH™ Clean Mint [Smooth Formula], Procter & Gamble)

• Tooth sensitivity was measured by tactile examination using the Yeaple probe and thermal examination using the Schiff Air Index.

• Oral soft tissue examinations were conducted and adverse events recorded.

• Subjects were randomized to either the stabilized stannous fluoride dentifrice or the control dentifrice.

• Subjects brushed twice daily with their assigned dentifrice using a manual soft toothbrush for 8 weeks.

• Subjects were examined again for tooth sensitivity and safety at weeks 4 and 8.

Results

• Data were analyzed for 77 subjects who had complete data.

• Yeaple Probe Index scores were statistically significantly higher for the stabilized stannous fluoride group than the sodium fluoride control group at both weeks 4 and 8 (P<0.0001). Higher Yeaple Probe Index scores indicate less tooth sensitivity.

• Compared to the sodium fluoride control group, the stabilized stannous fluoride group had a mean Yeaple Probe Index score 1.6 times that of the sodium fluoride group at week 4 and 2 times at week 8.

• Schiff Air Index scores were statistically significantly lower for the stabilized stannous fluoride group than the sodium fluoride control group at both weeks 4 and 8 (P<0.0001). Lower Schiff Air Index scores indicate less tooth sensitivity.

• Compared to the sodium fluoride control group, the stabilized stannous fluoride group showed a 36% lower Schiff Air Index score (adjusted mean) than the sodium fluoride group at week 4 and a 44% lower score at week 8.

• No adverse events were reported or observed.

Lower Schiff Air Index scores indicate less tooth sensitivity.

A CLINICAL TRIAL EVALUATING IMMEDIATE SENSITIVITY RELIEF OF A 0.454% STANNOUS FLUORIDE DENTIFRICE

Reference: He, ML Barker, Qaqish J, et al. J Clin Dent 2011; 22: 46-50.

Key Clinical Results

• The stannous fluoride (SnF₂) dentifrice provided superior sensitivity protection relative to the negative control immediately after the first use based on the Thermal Schiff Index (13.8%, P<0.0001) and the Thermal Air Visual Analog Scale (14.6%, P<0.0001). See Figures 1 & 2.

• The SnF2 dentifrice also provided superior (P<0.0001) relief relative to the negative control at Day 3 and at Week 2 based on the Thermal Schiff Air Index (31.8% and 61.3%, respectively), the Thermal Air Visual Analog Scale (34.8% and 66.6%, respectively) and the Tactile Yeaple Probe (186% and 239%, respectively). See Figures 1 & 2 and Table 1.

• The test products were well tolerated.

Figure 1. Thermal Schiff Air Index Adjusted Mean Scores (Lower score indicates less sensitivity)

Figure 1. Thermal Schiff Air Index Adjusted Mean Scores (Lower score indicates less sensitivity)

Figure 2. Mean tactile sensitivity scores at Baseline and Week 2. N=69

Figure 2. Mean tactile sensitivity scores at Baseline and Week 2. N=69

Objective

To evaluate the efficacy of a SnF₂ dentifrice in the reduction of dentinal hypersensitivity after immediate use, 3 days and 2 weeks of use as compared to a negative control dentifrice.

Study Design

• This was a controlled, randomized, examiner-blind, two-treatment, parallel group clinical trial.

• One hundred eleven healthy adult subjects with moderate dentinal hypersensitivity were enrolled and randomized to one of two treatment groups.

• Crest^® PRO-HEALTH^™ Advanced — 0.454% Stannous fluoride (1100 ppm fluoride), The Procter & Gamble Company, Cincinnati, OH.

• At the Baseline visit, subjects received an oral soft tissue (OST) exam to evaluate the overall health of the mouth and then were reassessed for tooth sensitivity. Subjects with at least two sensitive teeth demonstrating reproducible sensitivity to both thermal and tactile stimuli and who met all eligibility criteria were enrolled in the study. For those subjects who had greater than two teeth meeting the eligibility criteria, only two were selected for enrollment in the study.

• Subjects were then randomized to treatment (either Crest^® PRO-HEALTH^™ Sensitive Shield with 0.454% stannous fluoride, The Procter & Gamble Company or Colgate Cavity Protection dentifrice with 0.76% Sodium monofluorophosphate, Colgate-Palmolive). Products and treatment kits were identical in appearance to preserve blinding.

• Subjects were instructed, according to manufacturer’s usage instructions, to brush with their assigned dentifrice thoroughly twice a day (morning and evening). Subjects in the stannous fluoride dentifrice group brushed the sensitive teeth first.

• Subjects performed their first product use on site under the supervision of site staff. Immediately (within 5 minutes) following the first treatment, both the examiner and subjects re-assessed thermal sensitivity for each enrolled tooth using the Schiff Air Index (assessed by examiner) and Thermal Air Visual Analog Scale (assessed by subjects).

• Safety and efficacy measurements, using Schiff Air Index, Thermal Air Visual Analog Scale and Tactile Yeaple Probe, were re-assessed at the Day 3 and Week 2 study visits.

A RANDOMIZED CLINICAL TRIAL EVALUATING A 2-STEP STANNOUS FLUORIDE DENTIFRICE AND WHITENING GEL SYSTEM VERSUS A POTASSIUM NITRATE DENTIFRICE FOR SENSITIVITY RELIEF

Reference: Gerlach RW, Underwood J, Miner M. Data on file, 2016.

Key Clinical Results

• A 2-step stannous fluoride dentifrice and whitening gel system (Crest® PROHEALTH^™

   [HD]^™, CPH-HD) provided superior tactile and thermal sensitivity relief (P<0.05) versus a positive control potassium nitrate dentifrice (Sensodyne^® Extra Whitening). Both groups provided a significant benefit relative to baseline for both measures (P<0.0001). See Figures 1 & 2.

• Seventy-two percent (72%) of teeth tested in the CPH-HD group experienced an improvement in thermal sensitivity compared to 53% in the positive control group. Fifty-five percent of teeth tested using the CPH-HD product experienced relief from tactile sensitivity compared to 37% for the positive control.

Objective

To evaluate changes in dentinal hypersensitivity in response to using a two-step stannous fluoride dentifrice and whitening gel system relative to a positive control potassium nitrate sensitivity toothpaste.

• This was a randomized, controlled, double-blinded study to assess changes in dentinal hypersensitivity over a 2 week period.

• 71 healthy adult volunteers with current dentinal hypersensitivity were enrolled and randomized to one of the groups for twice a day oral hygiene:

  - Crest^® PRO-HEALTH^™ [HD]^™: Step 1 is a 0.454% stannous fluoride dentifrice; Step 2 is a 3% is a hydrogen peroxide whitening gel (Procter & Gamble)

- Positive Control: Sensodyne Extra Whitening with sodium fluoride and 5% potassium nitrate (GlaxoSmithKline)

- Both groups used a soft, manual toothbrush (Oral-B® Indicator®, Procter & Gamble) 

• Assessment of dentinal hypersensitivity was made at baseline (before any treatment) and after 2 weeks of using the randomly assigned treatment using the Schiff Air Index1 (thermal) and Yeaple Probe2 (tactile).

• Safety was assessed from clinical examination.

* via Step 1 stannous fluoride dentifrice

1 Schiff T, et al. J Clin Dent 1994;5 Spec No: 87-92.

2 Schiff T, et al. J Contemp Dent Pract 2006;May;(7)2:001-008.

3 Walters P. Dentinal Hypersensitivity: A Review. Updated Dec 2014; dentalcare.com CE Course #200.

4 Gerlach RW, et al. J Dent Res 2015;94 (Spec Iss A): Abstract 293.

5 Garcia-Godoy, C et al. J Dent Res 2016; 96 (Spec Iss A): Abstract 92.

Clinical Significance: Hypersensitivity

Clinical Studies