Comparative Evaluation of Nd:YAG Laser and Fluoride Varnish for the Treatment of Dentinal Hypersensitivity

Penetration and durability of CPP-ACP paste and sodium fluoride varnish as desensitizing agents: An in vitro comparison

Background

This study aimed to investigate and compare the penetration and durability of two dentin desensitizers, sodium fluoride varnish and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, using electron microscopy.

Methods

The study was performed on 60 dentin specimens prepared from extracted human premolars. After applying 17% EDTA to remove the smear layer, the specimens were divided into two groups. MI Paste and Bi-fluoride varnish were applied to the specimens. Microscopic images of 20 samples were obtained immediately. Twenty other samples were accessed after 15 days, and the other 20 were accessed after 30 days of toothbrushing and thermal cycling. Both surface and longitudinal cross-sectional images (after sample fracture) were studied. Data were analyzed with two-way ANOVA and Mann-Whitney U test at a significance level of P<0.05.

Results

The mean depth of material penetration was significantly time-dependent and fluctuated in both groups. There was a significant difference between the mean level of plugs between 0, 15, and 30 days (P<0.001). Penetration increased with time for the MI Paste group, while in the Bi-fluoride group, the increase was significant at 15 and 30 days than immediately after application. The mean thickness of the plugs was significantly different at the three time periods, and MI Paste showed a sudden decrease in plug thickness after 15 days.

Conclusion

Immediately after application, Bi-fluoride occluded dentinal tubules more effectively, and its durability after abrasion and thermal fatigue were higher than MI Paste.

Effect of Various Lasers With or Without Systemp.desensitizer on Dentine Tubules: An In Vitro Scanning Electron Microscopy Analysis

Objective: The current study was carried out to evaluate the effects of laser and Systemp.desensitizer therapy. Further, scanning electron microscopy (SEM) was used to determine the effects of individual or combined desensitizers on human dentinal tubules. Background: The most common clinical condition that makes people uncomfortable is dentin hypersensitivity (DH). Both lasers and drugs that reduce sensitivity have been used to treat DH. Materials and methods: A total of 100 dentinal samples were taken from newly extracted third molars (affected) and divided into 10 groups (A to J), that is, control (A); Systemp.desensitizer (B); diode laser (980 nm) (C); Nd:YAG laser (D); Er:YAG laser (E); Er,Cr:YSGG laser (F); Systemp.desensitizer + diode laser (G); Systemp.desensitizer + Nd:YAG laser (H); Systemp.desensitizer + Er:YAG laser (I); and Systemp.desensitizer + Er,Cr:YSGG laser (J). SEM was used to evaluate the dentinal specimens in each group (longitudinal and transverse portions), and then images of each sample were captured (20 images/sample). In addition, the number of open dentinal tubules was counted and then the occlusion depth in dentinal tubules was measured. Mann-Whitney and Kruskal-Wallis tests were employed to analyze the obtained data. Results: All treatment procedures and protocols were effective in blocking dentinal tubules (p < 0.05). Compared with the other groups, dentinal tubules in the laser and laser combination therapy groups were significantly obstructed (p < 0.05). Diode and Nd:YAG lasers with or without Systemp.desensitizer showed significantly more tubule occlusion and greater sealing depth than Er:YAG and Er,Cr:YSGG lasers with or without Systemp.desensitizer (p < 0.05). Conclusions: In summary, lasers alone or in combination can play a significant role in occluding the dentinal tubules. However, combining the diode or Nd:YAG laser with Systemp.desensitizers is a more effective treatment strategy and may have immediate and long-lasting effects.

Three-dimensional visualization of dentine occlusion based on FIB-SEM tomography

The occlusion of dentinal tubules has become a rapid and effective method for treating dentin hypersensitivity. Accurate evaluation of dentin occlusion is critical to illustrate the efficacy of oral care products and to optimize dental therapy in the clinics, which is limited by the conventional two-dimensional (2-D) characterization methods. Here, we demonstrate the visualization of the dentin occlusion via three-dimensional (3-D) characterization using a focused ion beam-scanning electron microscopy (FIB-SEM) tomography. Using the "Slice and View" approach, the material used for occluding dentin tubules is imaged with a very high-resolution voxel (10 nm × 10 nm × 20 nm) from 2-D SEM images and then reconstructed into a 3-D volume, which presents the mode of action of toothpaste for treating dentin hypersensitivity. Meanwhile, quantitative analysis of the depth of occlusion is successfully obtained. This work validates the feasibility of FIB-SEM tomography in the analysis of dentin occlusion within the complicated networks of dentine tubules at the nanoscale, and provides a novel approach to facilitate the research and development of oral care products.

Laser therapy for dentinal hypersensitivity

BACKGROUND

Dentinal hypersensitivity is characterized by short, sharp pain from exposed dentine that occurs in response to external stimuli such as cold, heat, osmotic, tactile or chemicals, and cannot be explained by any other form of dental defect or pathology. Laser therapy has become a commonly used intervention and might be effective for dentinal hypersensitivity.

OBJECTIVES

To assess the effects of in-office employed lasers versus placebo laser, placebo agents or no treatment for relieving pain of dentinal hypersensitivity.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 20 October 2020), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2020, Issue 9), MEDLINE Ovid (1946 to 20 October 2020), Embase Ovid (1980 to 20 October 2020), CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1937 to 20 October 2020), and LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; from 1982 to 20 October 2020). Conference proceedings were searched via the ISI Web of Science and ZETOC, and OpenGrey was searched for grey literature. The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomized controlled trials (RCTs) in which in-office lasers were compared to placebo or no treatment on patients aged above 12 years with tooth hypersensitivity.

DATA COLLECTION AND ANALYSIS

Two review authors independently and in duplicate screened the search results, extracted data, and assessed the risk of bias of the included studies. Disagreement was resolved by discussion. For continuous outcomes, we used mean differences (MD) and 95% confidence intervals (CI). We conducted meta-analyses only with studies of similar comparisons reporting the same outcome measures. We assessed the overall certainty of the evidence using GRADE.

MAIN RESULTS

We included a total of 23 studies with 936 participants and 2296 teeth. We assessed five studies at overall low risk of bias, 13 at unclear, and five at high risk of bias. 17 studies contributed data to the meta-analyses. We divided the studies into six subgroups based on the type of laser and the primary outcome measure. We assessed the change in intensity of pain using quantitative pain scale (visual analogue scale (VAS) of 0 to 10 (no pain to worst possible pain)) when tested through air blast and tactile stimuli in three categories of short (0 to 24 hours), medium (more than 24 hours to 2 months), and long term (more than 2 months). Results demonstrated that compared to placebo or no treatment the application of all types of lasers combined may reduce pain intensity when tested through air blast stimuli at short term (MD -2.24, 95% CI -3.55 to -0.93; P = 0.0008; 13 studies, 978 teeth; low-certainty evidence), medium term (MD -2.46, 95% CI -3.57 to -1.35; P < 0.0001; 11 studies, 1007 teeth; very low-certainty evidence), and long term (MD -2.60, 95% CI -4.47 to -0.73; P = 0.006; 5 studies, 564 teeth; very low-certainty evidence). Similarly, compared to placebo or no treatment the application of all types of lasers combined may reduce pain intensity when tested through tactile stimuli at short term (MD -0.67, 95% CI -1.31 to -0.03; P = 0.04; 8 studies, 506 teeth; low-certainty evidence) and medium term (MD -1.73, 95% CI -3.17 to -0.30; P = 0.02; 9 studies, 591 teeth; very low-certainty evidence). However, there was insufficient evidence of a difference in pain intensity for all types of lasers when tested through tactile stimuli in the long term (MD -3.52, 95% CI -10.37 to 3.33; P = 0.31; 2 studies, 184 teeth; very low-certainty evidence). Most included studies assessed adverse events and reported that no obvious adverse events were observed during the trials. No studies investigated the impact of laser treatment on participants' quality of life.

AUTHORS' CONCLUSIONS

Limited and uncertain evidence from meta-analyses suggests that the application of laser overall may improve pain intensity when tested through air blast or tactile stimuli at short, medium, or long term when compared to placebo/no treatment. Overall, laser therapy appears to be safe. Future studies including well-designed double-blinded RCTs are necessary to further investigate the clinical efficacy of lasers as well as their cost-effectiveness.

Efficacy of low-level laser therapy associated with fluoride therapy for the desensitisation of molar-incisor hypomineralisation: Randomised clinical trial

BACKGROUND

Molar-incisor hypomineralisation (MIH) is a qualitative enamel defect.

AIM

To investigate the low-level laser therapy (LLLT) associated with fluoride varnish for the desensitisation of teeth with MIH.

DESIGN

A randomised clinical trial was conducted with 66 children, randomly allocated to the treatments: laser (L); fluoride varnish (FV); and laser + fluoride varnish (L + FV). The participants in the L group underwent two sessions of LLLT (48-hour interval). The FV group received four applications of varnish at one-week intervals. The L + FV underwent two sessions of LLLT and four applications of varnish. Prior to each session and one month after the onset of treatment, tooth sensitivity and its magnitude were evaluated. Intra- and inter-group comparisons were performed (α = 5%).

RESULTS

A significant reduction in the mean sensitivity score was found over time in all groups. After the final treatment, a significant difference was found between the L and L + FV groups (P = .011), with a lower score in the L + FV group (0.09), whereas no difference was found between the FV and L + FV groups (P = .095).

CONCLUSIONS

Fluoride varnish and the combination of treatments (L + FV) had greater desensitising action on teeth with MIH. Laser therapy demonstrated an immediate desensitising effect, whereas fluoride varnish had a late-onset effect.

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.

Dentin Tubule Occlusion Potential of Novel Dentifrices Having Fluoride Containing Bioactive Glass and Zinc Oxide Nanoparticles

OBJECTIVE

To compare the in vitro potential of dentin tubule occlusion of two novel experimental dentifrices consisting of fluoride containing bioactive glass (BG) with zinc oxide nanoparticles.

MATERIALS AND METHODS

Forty-eight dentin discs (n = 48) were divided into 6 groups (n = 8), based on their brushing dentifrices: Group 1 = artificial saliva (AS; control); Group 2 = fluoride dentifrice (Colgate Palmolive©, UK); Group 3 = experimental nonactive agent dentifrice; Group 4 = experimental dentifrice with 1.5% BG; Group 5 = experimental dentifrice with 4% BG; and Group 6 = BioMinF© dentifrice. Postbrushing, the discs were subjected to acidic challenge with 6% wt citric acid (pH = 4.0) for 1 min. Scanning electron microscope (SEM) and energy-dispersive X-ray (EDX) spectroscopy were performed pre- and post-citric acid challenges, and percentages of tubule occlusion assessed.

RESULTS

SEM micrographs of group 1 (AS) show no tubule occlusion (0%), whereas those of groups 2 and 3 show partial tubule occlusion (25 to <50% of tubules occluded). The SEM micrographs of dentifrices containing fluoride-BG (groups 4, 5, and 6) show that most of the tubules (>50 and <100%) were occluded. For all the groups (excluding group 1), pre- and post-citric acid challenge values are statistically significant (p < 0.05). EDX analysis reveals the presence of zinc in experimental dentifrices only.

CONCLUSION

The results of novel experimental dentifrices are comparable to those of the BioMinF©, in terms of tubule occlusion. Dentifrices containing BG could serve as an alternative in dentin sensitivity management.

Effectiveness of Calcium Phosphate Desensitising Agents in Dental Hypersensitivity Over 24 Weeks of Clinical Evaluation

BACKGROUND

Calcium phosphate-based compounds are used to treat dental hypersensitivity (DH). Their long-term clinical behaviour needs further research. This study compared the 24-week effectiveness of Teethmate Desensitizer (TD), a pure tetracalcium phosphate (TTCP) and dicalcium phosphate dihydrate (DCPD) powder/water, to that of Dentin Desensitizer (DD), and Bite & White ExSense (BWE), both of calcium phosphate crystallites.

METHODS

A total of 105 subjects were selected. A random table was utilised to form three groups of 35 subjects. DH was evaluated using the evaporative sensitivity, tactile sensitivity tests, and the visual analogue scale (VAS) of pain. Response was recorded before the application of the materials (Pre-1), immediately after (Post-0), at 1 week (Post-1), 4 weeks (Post-2), 12 weeks (Post-3) and 24 weeks (Post-4). The non-parametric distribution was assessed with the Shapiro-Wilk statistical test. Intra-group differences for the six time points were evaluated with the Friedman statistical test and the Kruskal-Wallis test.

RESULTS

All the materials decreased DH after 24 weeks in comparison to Pre-1. However, the TTCP/DCPD cement showed the greatest statistical efficiency.

CONCLUSIONS

The significant decrease of VAS scores produced by TD in the long term suggest the material as the most reliable in the clinical relief of DH.

Clinical Evaluation of Nd:YAG Laser With and Without Dentin Bonding Agent for the Treatment of Occlusal Hypersensitivity

Purpose:

The aim of the present study was to evaluate and compare both the immediate and delayed desensitizing effects of the Nd:YAG (neodymium-doped:yttrium aluminum garnet; Nd3+:Y3Al5O12) laser with and without dentin bonding agent (DBA) on occlusal dentinal hypersensitivity (DH).

Methods and Materials:

Twenty-one patients with a total of 117 chronic occlusal hypersensitive teeth were selected. Each subject had at least three hypersensitive teeth. These teeth were randomly allocated into three groups: group 1, DBA on the occlusal surface; group 2, Nd:YAG laser (1064-nm wavelength, 30 mJ of energy, 10 pulse/s, 60 seconds, two times); and group 3, Nd:YAG laser (1064-nm wavelength, 30 mJ of energy, 10 pulse/s, 60 seconds, two times) with DBA. Pain was assessed using a visual analog scale after stimulation of the sensitive teeth by using the sharp tip of an explorer and an air blast prior to treatment and immediately, one week, one month, and three months after treatment by one blinded examiner.

Results:

A significant reduction in occlusal DH occurred at all time points in all of the experimental groups. The three groups showed significant improvements in discomfort immediately after treatment and after one week (p&lt;0.001), but the Nd:YAG laser with DBA group had greater efficacy when compared with the other groups. The Nd:YAG laser group and Nd:YAG laser with DBA group had no significant differences at one month and three months after treatment (p&gt;0.05); however, their desensitizing efficacy was superior to the DBA group.

Conclusions:

The Nd:YAG laser with DBA may be most effective in the long-term treatment of occlusal DH, although other measures also reduce DH.

Laser Effects on the Prevention and Treatment of Dentinal Hypersensitivity: A Systematic Review

Introduction: Dentinal hypersensitivity (DH) is an acute intensive tooth pain which can lead to dental annoyances during eating and drinking. Stimulating exposed dentinal tubules by either kind of thermal, tactile, chemical and/or osmotic stimuli is believed to be the cause of this pain. It is hypothesized that dentinal tubules' orifice occlusion (DOO) can help relieve such dental irritations. Thus, this systematic review was conducted to evaluate the effectiveness of laser application as a prevention and treatment modality on DH reduction. Methods: Electronic databases (MEDLINE, SCOPUS) were searched among randomized clinical trials from January 2007 to December 2016. The extraction of data and quality assessments were carried out by different independent observers. Results: A total of 499 items were found of which3 9 relevant articles were extracted. The profound findings proved lasers' effectiveness as a treatment of DH. Although some of the researches reported no significant difference between laser and other desensitizing agents, most of the studies suggested that better results (both rapid and long-lasting) were obtained in combined modalities. Furthermore, the preventive role of this new technology has been emphasized as well. Nd-YAG (neodymium-doped yttrium aluminum garnet) and diode lasers reduce DH after bleaching. Lasers can also protect cervical restorations from DH due to tubular occlusion. Moreover, it is suggested to apply lasers in relief of DH following scaling and root planning. Nevertheless, a few researchers dispute its beneficence as a result of placebo effect. Conclusion: The results obtained from several studies in the present review revealed that the application of lasers is effective not only in terms of treatment of DH, but also in the prevention of this intensive tooth pain. Among various types of lasers, the application of Nd:YAG laser has shown the best results in DH treatment.

Evaluation of the effects of Er:YAG laser, Nd:YAG laser, and two different desensitizers on dentin permeability: in vitro study

The purpose of this in vitro study was to evaluate and compare the efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser, neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, PrevDent nano-hydroxyapatite toothpaste plus Repairing Serum Kit (PNH), and NUPRO Sensodyne Prophylaxis Paste with NovaMin (NPP) on dentin permeability reduction. Forty dentin discs obtained from bovine incisors were divided into four study groups: Er:YAG laser-treated (2940 nm; 0.2 W, 80 mJ/pulse, 3 Hz); Nd:YAG laser-treated (1064 nm; 1 W, 10 Hz); PNH-treated; and NPP-treated groups. The quantitative changes in permeability of each dentin disc were measured using a computerized fluid filtration method (CFFM) before and after desensitizer treatments. The data were analyzed using the Wilcoxon, paired-samples t, Kruskal-Wallis, and Mann-Whitney U tests. The dentin surfaces and tubules were also morphologically detected by scanning electron microscopy (SEM). In all groups, dentin permeability was significantly reduced after the desensitizer and laser treatments (p < 0.05). Among the groups, we detected a significant difference in only when comparing the Er:YAG laser- and NPP-treated groups (p = 0.034). SEM analysis revealed physical changes in the dentin surface in all groups. This in vitro study shows that all tested desensitizers and laser treatments reduced dentin permeability. Also, surface changes, such as complete or partial occlusion or shrinkage of dentin tubules, were observed in all groups. Although the laser groups performed best, the PNH protocol can be considered as an alternative therapeutic product. In addition, clinical and laboratory studies should be performed for this product, and their efficacy should be assessed by combined therapy with lasers.

Low level laser therapy induces increased viability and proliferation in isolated cancer cells

OBJECTIVES

Low level laser therapy (LLLT), which stimulates natural biological processes in the application region, is frequently used in dental treatments. The aim of our study was to evaluate the effects of LLLT which could activate precancerous cells or increase existing cancerous tissue in case of clinically undetectable situations.

MATERIALS AND METHODS

Saos-2 osteoblast-like osteosarcoma cells and A549 human lung carcinoma cells were used. Twenty-four hours after preparation of cell culture plates, laser irradiation was performed 1, 2 and 3 times according to the test groups using Nd:YAG laser with the power output 0.5, 1, 2 and 3 W. Cell proliferation analysis was performed by MTT assay at the 24th hour following the last laser applications.

RESULTS

Generally, it was observed that the proliferation rates increased as the number of applications increased, when compared to the controls, especially in those cases in which the irradiation was performed 2 or 3 times more.

CONCLUSION

The findings of this study have led to the conclusion that LLLT increases cancer cell proliferation, depending on the power output level of the laser and the number of applications. In addition to the proliferation and mitotic activity of the cancer tissue cells, we concluded that LLLT, which is frequently used in dental practice, could activate precancerous cells or increase existing cancerous tissue.

Application of Diode Laser in the Treatment of Dentine Hypersensitivity

INTRODUCTION

Dentine hypersensitivity is characterized by acute, sharp pain arising from the exposed dentine, most commonly in response to thermal, tactile, or chemical stimuli, and which cannot be linked to any other pathological changes in the tooth or the environment. Therapy uses various impregnating agents in the form of solutions or gels and, in more recent times, laser.

AIM

The aim of this research was to examine the effects of treatment of hypersensitive dental cervix with diode laser.

MATERIALS AND METHODS

The study included 18 patients with 82 sensitive teeth. The degree of dentine hypersensitivity was evaluated by visual analogue scale (VAS), and the treatment was carried out by application of low-power diode laser over the span of three visits, which depended on the initial sensitivity.

RESULTS

There is a significant difference in VAS values measured at the onset of treatment (baseline) and immediately after the first laser treatment (t=9.275; p=0.000), after 7 days, after the second laser treatment (14 days) (t=7.085, p=0.000), as well as after 14 days and the third laser treatment (t=5.517, p=0.000), which confirms the effectiveness of this therapeutic procedure. The results showed a reduction of hypersensitivity in response to tactile stimulus with a probe after the third treatment, even with teeth whose value on the VAS was very high at the beginning of treatment (baseline).

CONCLUSION

Within the scope of the conducted study, laser therapy has provided extremely safe and effective results in the treatment of cervical dentine hypersensitivity.

Effects of a Dicalcium and Tetracalcium Phosphate-Based Desensitizer on In Vitro Dentin Permeability

The present study evaluated the effectiveness of a dicalcium and tetracalcium phosphate-based desensitizer in reducing dentin permeability in vitro. Dentin fluid flow was measured before and after treatment of dentin with patent dentinal tubules using 1 or 3 applications of the dicalcium and tetracalcium phosphate containing agent TeethmateTM (TM) and comparing the results with two sodium fluoride varnishes VellaTM (VLA) and VanishTM (VAN), after storage in artificial saliva for 24 h, 48 h and 7 days. Significant differences were observed among the 4 methods employed for reducing dentin permeability (p < 0.001) and the 3 post-treatment times (p < 0.001). VLA and VAN never achieved 50% permeability reductions consistently in any of the 3 time periods. Only the calcium phosphate-based desensitizer applied for 3 times consistently reduced dentin permeability by 50% after 24 h. When applied once, the permeability reduction of TM increased progressively over the 3 time periods. After 7 days, only one and three applications of the calcium phosphate-based desensitizer consistently reduced dentin permeability by more than 50%. Permeability reductions corresponded well with scanning electron microscopy examination of dentinal tubule orifice occlusion in dentin specimens treated with the agents. Overall, the dicalcium and tetracalcium phosphate-based desensitizer is effective in reducing dentin permeability via a tubule occlusion mechanism. The ability of the agent to reduce dentin permeability renders it to be potentially useful as a clinical dentin desensitizing agent, which has to be confirmed in future clinical studies. By contrast, the two sodium fluoride varnishes are not effective in dentin permeability reduction and should be considered as topical fluoride delivering agents rather than tubular orifice-blocking agents.

Evaluation of dentinal tubule occlusion and depth of penetration of nano-hydroxyapatite derived from chicken eggshell powder with and without addition of sodium fluoride: An in vitro study

Aim:

This in vitro study evaluated the degree of dentinal tubule occlusion and depth of penetration of nano-hydroxyapatite (nHAp) derived from chicken eggshell powder with and without the addition of 2% sodium fluoride (NaF) using scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM).

Materials and Methods:

nHAp was synthesized and characterized using X-ray diffraction and SEM-energy dispersive spectroscopy. Dentin discs were obtained from extracted teeth, pretreated with 17% ethylenediaminetetraacetic acid for 5 min and were divided into four groups based on the experimental agents as follows: Group 1: Untreated (control), Group 2: 2% NaF, Group 3: nHAp, Group 4: Combination of nHAp and 2% NaF. The treatment protocol was carried out for 7 days, after which the specimens were viewed under SEM and CLSM.

Statistical Analysis Used:

One-way ANOVA and Tukey's post hoc multiple comparison tests (P < 0.05).

Results:

All the experimental agents occluded the dentinal tubules, but to varying degrees and depths. Specimens treated with the combination of nHAp and 2% NaF showed complete dentinal tubular occlusion and significantly greater depth of penetration than those treated with nHAp and 2% NaF alone.

Conclusion:

The combination of nHAp and 2% NaF was the most effective in occluding dentinal tubules.

Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications

Background:

Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique.

Materials and Methods:

Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3–0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine.

Results:

The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer.

Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength.

Conclusions:

Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

Combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine

OBJECTIVE

This study evaluated the combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine.

DESIGN

Sixty slabs of bovine root dentine (2×2×2mm) were eroded with citric acid 0.3% (pH 3.2) during 2h and then kept in artificial saliva during 24h. Specimens were randomly assigned in 6 groups (n=10), to receive the following treatments: fluoride varnish; fluoride varnish+Er:YAG laser; fluoride varnish+Nd:YAG laser; non-fluoride varnish; non-fluoride varnish+Er:YAG laser; non-fluoride varnish+Nd:YAG laser. The Er:YAG (100mJ, 3Hz) and Nd:YAG (70mJ, 15Hz) were applied for 10s. Specimens were subjected to further erosive challenges with citric acid 0.3% 4×/day, during 1min, for 5 days, remaining in artificial saliva between cycles. Dentin permeability was then assessed. Two-way ANOVA demonstrated no significant interaction between laser and varnish (p=0.858).

RESULTS

No effect was also detected for the main factor varnish (p=0.768), while permeability of eroded root dentin was significantly lower when such substrate was laser-irradiated, no matter the laser source (p<0.001).

CONCLUSIONS

This study concluded that Er:YAG and Nd:YAG lasers can be employed to control the permeability of eroded root dentin, regardless of fluoride varnish application.

The synthesis and characterization of a novel potassium chloride-fluoridated hydroxyapatite varnish for treating dentin hypersensitivity

Dentin hypersensitivity is treated using materials that occlude the dentinal tubules or release potassium ions that induce nerve desensitization. In this study we formulated a novel varnish containing potassium chloride and fluoridated hydroxyapatite and evaluated its physical properties and cytotoxicity. Potassium ion release from the varnish was measured. Dentin permeability was evaluated by measuring the hydraulic conductance of etched dentin discs treated with the varnish. The direct contact test and MTT assay were performed to evaluate the varnish's cytotoxicity. We found that the varnish released potassium ions over 6 h, and demonstrated a statistically higher reduction in dentin permeability compared to commercial fluoride varnish or control. Dentin disc scanning electron microscopy images demonstrated occluded dentinal tubules in the novel varnish group after brushing. The cytotoxicity tests indicated the varnish was biocompatible with gingival and pulpal fibroblasts. We propose the novel varnish is a potential material for use in hypersensitivity management.

Lasers for the Treatment of Dentin Hypersensitivity

This systematic review and meta-analysis assessed the efficacy of lasers in reducing dentin hypersensitivity (DH) as compared with placebo or no treatment. Seven electronic databases and a manual search resulted in 2,538 unique publications. After selection, 13 studies were included in the meta-analysis. A CONSORT-based quality assessment revealed that 3 and 10 studies were at low and high risk of bias, respectively. A random-effects model with the generic inverse variance standardized mean difference (SMD) was used because of expected heterogeneity. Meta-analyses of the baseline-end of follow-up changes in pain revealed no differences for Er,Cr:YSSG vs. placebo (SMD = 2.49; 95% CI, -0.25 to 5.22; p = .07) but did reveal differences in favor of lasers for Er:YAG vs. placebo (SMD, 2.65; 95% CI, 1.25 to 4.05; p = .0002), Nd:YAG vs. placebo (SMD, 3.59; 95% CI, 0.49 to 6.69; p = .02), and GaAlAs vs. placebo (SMD, 3.40; 95% CI, 1.93 to 4.87; p < .00001). High and significant heterogeneity was found for all comparisons. In conclusion, Er:YAG, Nd:YAG, and GaAlAs lasers appear to be efficacious in reducing DH. However, given the high heterogeneity of the included studies, future randomized controlled clinical trials are needed to confirm these results.

Immediate and short-term effects of in-office desensitizing treatments for dentinal tubule occlusion

OBJECTIVE

The objective of this in vitro study was to evaluate the immediate and short-term effects of laser neodymium-doped yttrium aluminum garnet (Nd:YAG) irradiation and in-office desensitizing treatment on dentin tubule occlusion.

BACKGROUND DATA

Literature shows a lack of long-lasting treatments for dentin hypersensitivity.

METHODS

Forty-eight dentin slabs (4×4×2 mm) were ground flat, polished, and treated with 27% ethylenediaminetetraacetic acid (EDTA) to open the dentinal tubules. Specimens were randomly divided into the following experimental groups (n=12): Group 1: Control (no treatment); Group 2: Nd:YAG laser irradiation (100 mJ, 85 J/cm(2) per pulse with a quartz fiber of 400 μm, in scanning movements); Group 3: In-office prophylaxis with pumice; Group 4: In-office Colgate Sensitive Pro-Relief™ Desensitizing Paste. Treatments were performed according to the manufacturer's instructions. After treatment, the specimens were submitted to a sequence of erosive and abrasive challenges, twice a day for 5 days. The specimens were qualitatively and quantitatively evaluated by scanning electron microscopy immediately after treatment and after 4 and 5 days. The response variable was the amount of occluded dentin tubules per area, determined by three different examiners with the use of visual criteria, with a standardized grade created in the PowerPoint program. Data were compared with ANOVA and Tukey's test, considering a 5% significance level.

RESULTS

Immediately after treatment, a reduction in the number of opened dentin tubules was observed for the laser group when compared with the control group (p<0.05). After the experimental procedures, there were no quantitative differences between the amount of opened dentin tubules for all groups; however, micrographs showed some qualitative tubule occlusion for the laser group after the erosive/abrasive challenge.

CONCLUSIONS

only laser irradiation was capable of immediately sealing the dentinal tubules; however, none of the treatments showed efficacy in maintaining tubule occlusion after the chemical and mechanical challenges.

Short-term response of three resin-based materials as desensitizing agents under oral environmental exposure

OBJECTIVE

This paper focuses on clinical responses after 7 days of oral exposure to two resin-based materials as desensitizing agents compared to a fluoride varnish and on morphological and analytical study as a means to elucidate the mechanism of action.

MATERIALS AND METHODS

The elemental composition of Vertise™ Flow (VF), Universal Dentine Sealant (UDS) and Flor-Opal® Varnish (FOV) were investigated by using an X-ray energy dispersive spectrometer (EDX) in conjunction with a scanning electron microscope (SEM). SEM morphology of the material-treated dentine surfaces and pain reduction ability according to the Visual Analogue Scale (VAS) were evaluated in selected hypersensitive teeth. Post treatments and 7 day controls were recorded with SEM and VAS measurements. Clinical data was analysed with the Student's t-test for paired data, with a 5% significance level.

RESULTS

Silicon, ytterbium and alumina were the most present elements in VF, whilst calcium, chloride, silicon and alumina were highest in UDS. Within a 7 day oral environment all the tested materials modified the treated-dentine surfaces showing tubular occlusion of different morphology. Clinically, the efficacy of all materials was similar after a 7-day examination. However, VAS scores were significantly reduced if compared with the baseline (p < 0.05).

CONCLUSIONS

Within the limits of this study, data indicate that both resins are effective in sealing tubules and reducing VAS. A resin-related effect on the dentine's morphology was observed, which may influence the long-term response of the resins in the treatment of dental hypersensitivity, which requires further investigation.

Comparative evaluation of the effects of Nd:YAG laser and a desensitizer agent on the treatment of dentin hypersensitivity: a clinical study

Abstract Objective: The aim of this randomized longitudinal clinical study was to assess different treatment protocols for dentin hypersensitivity with high-power laser, desensitizing agent, and its association between high-power laser and desensitizing agent, for a period of 6 months.

BACKGROUND DATA

The literature shows a lack of treatment for dentin hypersensitivity, and lasers are contemporary alternatives.

METHODS

After inclusion and exclusion analysis, volunteers were selected. The lesions were divided into three groups (n=10): G1, Gluma Desensitizer (Heraeus Kulzer); G2, Nd:YAG Laser (Power Laser(™) ST6, Lares Research®) contact mode, laser protocol of 1.5 W, 10 Hz, and 100 mJ,≈85 J/cm(2), four irradiations performed, each for 15 sec, in mesiodistal and occluso-apical directions, totaling 60 sec of irradiation with intervals of 10 sec between them; G3, Nd:YAG Laser+Gluma Desensitizer. The level of sensitivity to pain of each volunteer was analyzed by visual analog scale (VAS) using cold air stimuli and exploratory probe 5 min, 1 week, and 1, 3, and 6 months after treatment. Data were collected and subjected to statistical analysis that detected statistically significant differences between the various studied time intervals of treatments (p>0.05).

RESULTS

For the air stimulus, no significant differences were found for each time interval. For the long-term evaluation, all groups showed statistical differences (p>0.05), indicating that for G2 and G3, this difference was statistically significant from the first time of evaluation (post 1), whereas in G1, the difference was significant from the post 2 evaluation (1 week). Comparison among groups using the probe stimulation showed significant differences in pain (p<0.001). Only in G1 and G3 did this difference become significant from post 01.

CONCLUSIONS

All protocols were effective in reducing dentinal hypersensitivity after 6 months of treatment; however, the association of Nd:YAG and Gluma Desensitizer is an effective treatment strategy that has immediate and long-lasting effects.

The role of fluoride in the preventive management of dentin hypersensitivity and root caries

Objective

The objectives were to bring light on fluoride to control dentin hypersensitivity (DHS) and prevent root caries.

Materials and methods

Search strategy included papers mainly published in PubMed, Medline from October 2000 to October 2011.

Results

Fluoride toothpaste shows a fair effect on sensitive teeth when combined with dentin fluid-obstructing agents such as different metal ions, potassium, and oxalates. Fluoride in solution, gel, and varnish give an instant and long-term relief of dentin and bleaching hypersensitivity. Combined with laser technology, a limited additional positive effect is achieved. Prevention of root caries is favored by toothpaste with 5,000 ppm F and by fluoride rinsing with 0.025–0.1 % F solutions, as the application of fluoride gel or fluoride varnish three to four times a year. Fluoride measures with tablets, chewing gum, toothpick, and flossing may be questioned because of unfavorable cost effectiveness ratio.

Conclusion

Most fluoride preparations in combination with dentin fluid obstruction agents are beneficial to reduce DHS. Prevention of root caries is favorable with higher fluoride concentrations in, e.g., toothpaste.

Clinical relevance

Fluoride is an effective agent to control DHS and to prevent root caries particularly when used in higher concentrations.

In situ effect of dentifrices associated to CO2 laser in the permeability of eroded root dentin

OBJECTIVE

The aim of this study was to evaluate, through a crossover 2×2 in situ trial, the effect of a desensitizing dentifrice associated with CO2 laser irradiation to control the permeability of eroded root dentin.

BACKGROUND DATA

Facing the increased prevalence of erosive lesion and the need for preventive means to control painful symptoms related to them.

METHODS

Eighty slabs of bovine root dentin were subjected to initial erosive challenge (citric acid 0.3%, 2 h), followed by a remineralizing period in artificial saliva (24 h). Specimens were then divided according to dentin treatment: desensitizing dentifrice, desensitizing dentifrice+CO2 laser, fluoride anticavity dentifrice. and fluoride anticavity dentifrice+CO2 laser. After a 2-day lead-in period, 10 volunteers wore an intraoral palatal appliance containing four root dentin slabs, in two phases of 5 days each. During the intraoral phase, one side of the appliance was immersed in 0.3% citric acid, and the opposite side was immersed in deionized water, four times a day. One hour after the immersions, all specimens were brushed with dentifrice slurry provided by the researcher. After a 7-day washout period, volunteers were crossed over on the different dentifrice group. Each phase having been completed, the specimens were evaluated for permeability through an optical microscope.

RESULTS

Data were analyzed using ANOVA and no significant difference (p=0.272) was found between the surface treatments performed on bovine root dentin.

CONCLUSIONS

It can be concluded that fluoride anticavity or desensitizing dentifrice, regardless of the association with the CO2 laser irradiation, was able to control the permeability of eroded root dentin.

Comparative assessment of the sealing ability of Nd:YAG laser versus a new desensitizing agent in human dentinal tubules: a pilot study

Dentinal hypersensitivity is a painful condition that occurs following periodontal treatment. Many treatment alternatives have been considered for this problem, including treatments with laser and dentinal adhesives. This study compared the sealing ability of Nd:YAG laser versus a new resin in scanning electron microscopy (SEM) micrographs. Ten human premolars were sectioned yielding 30 specimens of each premolar, which were randomly divided into three groups. The laser group was irradiated by Nd:YAG laser (1 W, 10 Hz, 60 s), the resin group was treated with the new Seal & Protect resin according to the manufacturer's instructions, and the third group served as the control group and did not receive any interventions. After preparation and gold coating of the samples, they were photographed by SEM at two magnifications (1500× and 4000×). The number and diameter (μm) of the dentinal tubules were recorded in selected fields, and analysis of variance (ANOVA) and Tukey tests were used to determine significant differences between groups. The ANOVA results revealed significant differences in both the mean number (P < 0.001) and diameter (P < 0.05) among the three groups. Further statistical analysis showed a significant difference between the laser group and the resin group in both outcome measures (P < 0.05). Thus, both Nd:YAG laser and the new resin reduced the number and diameter of open dentinal tubules, a result that also explains the desensitization mechanism of these interventions. We further conclude that application of the new resin is more effective than Nd:YAG laser in minimizing the number and diameter of exposed dentinal tubules.

Evaluation of pain levels after Nd: YAG laser and scalpel incisions: an experimental study in rats

BACKGROUND

Postoperative pain is a recognized sequel of periodontal surgery. The pain experience has been shown to peak in the first 24 hours following the procedure, and to decrease rapidly in subsequent days. The aim of the present study was to evaluate the pain levels following scalpel- and laser-incision of rat hind paws.

METHODS

The study was carried out on 10 albino Wistar male rats. Rats were randomly assigned to two groups: Group I (n = 5, laser surgery), or Group II (n = 5, conventional surgery with scalpel). For measuring mechanical hyperalgesia, the nociceptive threshold of the hind paw after mechanical stimulation was quantified using a Basile algesimeter. The measurements were done before the surgery and on the postoperative 1(st), 2(nd), 3(rd), and 7(th) days.

RESULTS

While the pain levels of the groups were similar before the surgical procedures, the laser-applied rats had significantly fewer nociceptive thresholds of the hind paw after mechanical stimulation compared with the scalpel-incised rats on the postoperative 1(st), 2(nd), 3(rd), and 7(th) days. Functional complications were not observed in the laser groups at three days after the surgery.

CONCLUSION

The results suggested that, for soft tissue surgery, Nd: YAG lasers have often led to shorter operative times, less pain, and fewer postoperative adverse events.