Laboratory evaluation of dentin tubule occlusion after use of dentifrices containing stannous fluoride

The effect of stannous fluoride desensitizing toothpaste on immediate dentin sealing ability of universal adhesive in vitro

Background/purpose

The stannous fluoride pretreatment of dentin may compromise the bond formation of the dentinal adhesive system. This study aimed to determine the effect of stannous fluoride (SnF2) desensitizing toothpaste on immediate dentin sealing ability (IDS) of universal adhesive in human intact dentin using dentin permeability test and scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS).

Materials and methods

Sixty sound dentin specimens were prepared from 60 extracted intact third molars, then treated with 17 % EDTA for 60 s to simulate hypersensitive dentin, and randomly divided into 2 series. Series 1 (dentin permeability test; n = 40) had 4 different treatment groups: (1) universal adhesive (self-etch mode), (2) universal adhesive (total-etch mode), (3) SnF2 pretreatment + universal adhesive (self-etch), (4) SnF2 pretreatment + universal adhesive (total-etch). The IDS of each group was the percentage decrease of hydraulic conductance of dentin after bonding. Series 2 (n = 20) was SEM-EDS analysis of different treated dentin before bonding. The data were analyzed using 2-way ANOVA and Tukey test.

Results

In groups of no SnF2 pretreatment, the IDS of universal adhesive were 79.53 ± 20.71 and 77.34 ± 18.14 % for self-etch and total-etch mode, respectively. In groups of SnF2 pretreatment, the corresponding values were 71.54 ± 15.56 and 69.56 ± 9.92 %, respectively. Although SnF2 pretreated-dentin had the remarkable signals of silicon and tin, there were no significant reductions in the IDS of universal adhesive (P < 0.05).

Conclusion

SnF2 desensitizing toothpaste has no adverse effect on the immediate dentin sealing ability of universal adhesive.

Dentinal tubule occlusion effects of dipotassium oxalate and diode laser combination: a single-blind in vitro study

BACKGROUND

Dentin hypersensitivity (DH) affects many patients. Various therapeutic options have been devised to alleviate this condition by achieving dentinal tubules (DT) occlusion. This research aimed to investigate the effects of dipotassium oxalate-containing mouthwash, diode laser and their combination on DT occlusion.

METHODS

Forty dentin samples were obtained from 20 human single-rooted third molars, 40 dentin specimens were obtained, and exposed DT were created in vitro. They were assigned into four groups: Group 1 (n = 10), the control group where no treatment was applied; Group 2 (n = 10), a mouthwash with a 1.4% dipotassium oxalate was applied twice for 60 s during a 5-day period in a shaker at 100 rpm; Group 3 (n = 10), a combination of the same mouthwash and an 810 nm diode laser at an output power of 0.25 W in continuous mode was applied for 60 s without contact at a distance of 3-4 mm; and Group 4 (n = 10), only a diode laser with the same protocol was applied. Occlusion of the DT was observed by scanning electron microscopy.

RESULTS

The analysis revealed occlusion of the DT in all treatment groups; however, the effects were more pronounced in the combined treatment group (Group 3). Compared with the test groups, the control group had significantly more open DT in 100 µm2 (p < 0.01). The difference between the Group 2 and Group 4 was not significant (p > 0.05).

CONCLUSION

DT occlusion was achieved via the use of a mouthwash containing 1.4% dipotassium oxalate and an 810 nm diode laser. However, the combination resulted in the greatest results and therefore may be utilized in individuals with DH.

The potential of galactomannan from Caesalpinia ferrea on erosive dentin wear reduction in vitro

Gels containing juca seed galactomannan (JSG) were evaluated for their potential to prevent the progression of dentin erosive wear in an in vitro study with four experimental groups (n = 9). The treatments included distilled water (DW), 0.05% stannous fluoride (121 ppm F), and 0.5% or 1% JSG. The specimens underwent a cycle (3 times/day) consisting of immersion in 1% citric acid (5 minutes), treatment (5 minutes), and artificial saliva exposure (2 hours/overnight) for 5 days. Surface changes were assessed using mechanical profilometry (wear), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The data were analyzed using ANOVA followed by Tukey's post-test (p < 0.05). The negative control group exhibited the highest wear (6.0 µm ± 3.5), significantly differing from the group treated with 0.05% stannous fluoride gel (p = 0.007), which showed less dentin loss. The groups treated with 0.5% and 1% JSG showed results similar to the negative control (p = 0.661; p = 0.212, respectively) and the stannous fluoride group (p = 0.103; p = 0.379, respectively). In the SEM images, the specimen treated with stannous fluoride showed obliterated tubules, while the JSG gels formed crystals on the dentin surface, as confirmed by the presence of oxygen and calcium in the EDS analysis. Although the JSG gels showed similar results to the stannous fluoride, did not exhibit superior efficacy at the tested concentrations.

The effect of iontophoresis delivery of fluoride in stannous fluoride desensitizing toothpaste on dentin permeability in human extracted teeth

This study aimed to determine the effect of iontophoresis delivery of fluoride in stannous fluoride (SnF₂) toothpaste on dentin permeability in human extracted third molars. For dentin permeability test, 26 dentin specimens were randomly divided into 4 groups; SnF₂ without-iontophoresis (n = 10), SnF₂ with-iontophoresis (n = 10), no SnF₂ without-iontophoresis (n = 3), and no SnF₂ with-iontophoresis (n = 3). The hydraulic conductance of dentin (HD) was measured after smear layer removal, immediate treatment, 7 days, and acid challenge. The other 26 specimens were also prepared under these different conditions to assess degree of dentinal tubule occlusions using scanning electron microscopy (SEM). Percentage decrease of HD in SnF₂ without-iontophoresis after immediate treatment, 7 days and acid challenge were 38.38 ± 13.61, 56.92 ± 17.22 and 33.07 ± 23.57%. The corresponding values in SnF₂ with-iontophoresis were 42.16 ± 14.49, 62.35 ± 15.67 and 50.01 ± 12.60%, respectively. There was a significant difference between without- and with-iontophoresis groups after acid challenge (p < 0.05). For SEM, after 7 days, SnF₂ with-iontophoresis showed deeper dentinal tubule occlusion (p < 0.05) and more resistance to acid challenge than SnF₂ without-iontophoresis. No significant change was observed in groups of no SnF₂ treatment. Cathode iontophoresis could enhance the effect of SnF₂ toothpaste in decreasing dentin permeability and increasing resistance to acid challenge.

In vitro evaluation of Sensi-IP®: A soluble and mineralizing sensitivity solution

OBJECTIVES

Sensi-IP®OG (SIP-OG) and Sensi-IP®FF (SIP-FF) are soluble bioactive glasses developed to treat dentin hypersensitivity and promote remineralization. Evaluation of their therapeutic potential to reduce dentin hypersensitivity and recover enamel strength was evaluated using standardized in vitro assessments based on simulated use.

METHODS

To assess dentin occlusion a visual occlusion methodology was employed. Dentin discs were subjected to twice-daily simulated brushing (for 5 days) using 0.67 g of toothpaste for 10 s. Simple prototype toothpastes containing SIP-OG and SIP-FF were compared to commercially available controls: Colgate® Sensitive Pro-Relief (CPR) and Sensodyne® Repair and Protect with NovaMin® (SRP). Samples were stored in artificial saliva between treatments. All samples were assessed at baseline and subsequent to each treatment and were scored on a 5-point categorical scale for occlusion. For enamel surface effects, test articles of SIP-OG, SIP-FF, and SIP-FF with NaF were compared to a positive (with NaF) and a negative (no NaF) control paste. Enamel samples were subjected to a pH cycling regime, providing exposure to the toothpaste slurry (i.e., 2 parts deionized water to 1 part toothpaste), mineralizing solution, and demineralizing solution over 5 days of simulated use. Samples were stored overnight in mineralizing solution. Samples were evaluated for fluoride uptake and changes to surface microhardness.

RESULTS

Visual occlusion scores (1 fully occluded to 5 unoccluded) were 2.6, 3.8, 4.4 and 4.0 after 1 day of simulated use for SIP-OG, SIP-FF with NaF, Colgate® Sensitive Pro-Relief and Sensodyne® Repair and Protect, respectively, decreasing to 1.0, 1.8, 3.1 and 3.9 after 5 days of application. SIP-OG provided superior occlusion at the significance level of p ≤ 0.05 at 1, 2, 3, 4, and 5 days. SIP-FF with NaF provided superior occlusion at the significance level of p ≤ 0.05 at 2, 4, and 5 days. Fluoride uptake ranged from 9.0 μg/cm² for SIP-OG to 12.4 μg/cm² for SIP-FF with NaF. Surface microhardness after acid cycling allowed recovery of 59 % of surface microhardness after treatment with SIP-OG or SIP-FF with NaF. SIP-OG achieved significant surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05. SIP-FF with NaF achieved surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05.

CONCLUSIONS

Superior occlusion of dentin tubules was observed with both novel additives compared to commercially available toothpastes. A build-up effect with increasing occlusion was noted with repeated application for both novel additives and ascribed to mineralization effects, as supported by surface microhardness recovery on initial enamel lesions.

Quantitative assessment of dentine mineralization and tubule occlusion by NovaMin and stannous fluoride using serial block face scanning electron microscopy

Dentine hypersensitivity (DH) is one of the most common dental conditions affecting most adults during their lifetime. Tubule occlusion is a widely accepted method for treating DH. Current in-vitro techniques such as focused ion beam, scanning electron microscopy (SEM), or hydraulic conductance that are used to determine tubule occlusion do not provide the depth of occlusion, are time-consuming, expensive and the volume of dentine tested is limited. The presented study aimed to assess the ability of serial block-face SEM (SBF-SEM) to section dentine, to quantify the number of occluded tubules including the depth of penetration by NovaMin and stannous fluoride (SnF₂ ) and to compare mineral density between the control and treated dentine. Results demonstrated that NovaMin provided a better occlusion with 100% of the tubules blocked at the surface compared to 83% for SnF₂ . The grayscale value (230.42) was significantly higher (p ≤ 0.05) after treatment with NovaMin compared to SnF₂ (222.06) and the control (196.37), indicating increased mineral density and dentine mineralization. SBF-SEM has the potential to be used for large volume analysis of bone-like materials at high resolution with minimal sample preparation over a short period. It can be significantly useful in the development and research of new biomaterials.

Effectiveness of diode laser and fluoride on dentin hypersensitivity treatment: A randomized single-blinded clinical trial

BACKGROUND

This randomized single-blinded clinical trial aimed to evaluate the effectiveness of diode laser and fluoride in the treatment of dentin hypersensitivity (DH) due to gingival recession.

MATERIALS AND METHODS

Twenty-eight individuals randomly distributed across three groups participated: 10 individuals who were treated with diode laser, nine who were treated with fluoride, and nine who received placebo. Pain was assessed with the Visual analog scale (VAS). Evaporative stimulus and tactile stimulus were evaluated with the verbal rating scale (VRS). VAS was applied shortly after, 6 h after, 12 h after, and 24 h after the single-session treatment for DH, whereas VRS was applied shortly after, 15 min and 7 days after the treatment. Participants' quality of life was assessed with the validated Brazilian version of the Dentine Hypersensitivity Experience Questionnaire assessing functional limitations, coping behaviors, emotional, and social impacts caused by DH. Descriptive statistics and the ANOVA test were used. Values of P < 0.05 were statistically significant.

RESULTS

Diode laser significantly reduced the DH to the evaporative stimulus (P = 0.002). The application of fluoride did not change the degree of DH to evaporative and tactile stimuli (P > 0.05). The group of individuals who were treated with diode laser presented a higher reduction in DH (25.4%) when compared to the group of individuals treated with fluoride (17.1%), and the group of individuals among whom placebo had been used (2.9%). Descriptive analysis indicated that the items measuring the emotional and social impacts of DH were those with a more negative impact on the individuals.

CONCLUSION

Therapy with diode laser was more effective in reducing DH than therapy with fluoride.