Comparative Morphologic Evaluation and Occluding Effectiveness of Nd: YAG, CO2 and Diode Lasers on Exposed Human Dentinal Tubules: An Invitro SEM Study

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.

Comparison of the Effects of Gluma Gel, Sensodyne Repair and Protect Toothpaste, and an 810 nm Low Power Diode Laser on the Closure of Dentinal Tubules: An In Vitro Study

Introduction: One of the common problems among dental patients is tooth hypersensitivity. There are various treatments for hypersensitivity, such as gels, solutions, toothpaste, and laser treatments. This report examined the effect of three treatments, namely 810 nm wavelength diode laser, Gluma gel, and Sensodyne Repair and Protect toothpaste, on tooth hypersensitivity. Methods: This experimental survey selected 40 premolars free of caries, fractures, restorations, root canal therapy, or wear. The enamel of the midline in the cervical part of the buccal surface was removed by a bur (the area was 2*2 mm and the depth was 2 mm), and the samples were then prepared and divided into four groups. Sensodyne Repair and Protect toothpaste, Gluma gel, and an 810 nm diode laser with 0.5 W power were applied to three groups of teeth. The samples were analyzed by using a field emission scanning electron microscope (FE-SEM). The data from the occluded dentinal tubules, partially occluded tubules, and open tubules were analyzed by using the Tamhane test. Results: The amount of occluded dentinal tubules was 83.2±9% in the laser group, 74.4±11.62% in the Gluma group, 67.1±18% in the Sensodyne group, and 15.03±3.39% in the control group. The difference between the treatment groups and the control group was meaningful (P<0.05). However, the difference between the Gluma group, the Sensodyne group, and the 810 nm laser group was not significant (P>0.05). Conclusion: The three treatments (810 nm diode laser, Gluma, and Sensodyne) were all effective in occluding dentinal tubules compared to the control group. However, there was no significant difference between these three treatment methods (P>0.05).

An SEM study on the effect of 9.3-µm CO2 laser on dentinal tubules for hypersensitivity treatment

OBJECTIVES

In-vitro studies were performed on dentin of extracted human molars to investigate the effectiveness of 9.3 μm CO2 laser irradiation to occlude dentinal tubules. The observed occlusion of dentinal tubules with the irradiation was compared with application of three reagents: 2% Sodium Fluoride gel, an aqueous solution of hydroxyapatite nanoparticles and an equal mix of the two. We show that 9.3 μm CO2 laser irradiation occludes dentinal tubules, and the use of laser irradiation produces better occlusion of the opened tubules compared to the use of topical reagents.

METHODS

Nine extracted and cleaned human molars were cut to obtain dentin disks of thickness of 3-5 mm. Each disc was divided into four quarters, and each quarter served as two samples corresponding to irradiated and non-irradiated group counterparts. Five disks were used to study the effect of various laser irradiation energies on the dentinal tubules to find a good pulse fluence for occlusion of the dentinal tubules, and four disks were used for studying the effects of reagents and irradiation at the pulse fluences found in the first part of the study. The samples were irradiated with a beam diameter of 1 mm (1/e2) at 15 Hz pulse repetition rate, scanned automatically using a set of scanning mirrors. Samples were imaged using Scanning Electron Microscope (SEM) which were processed to determine tubule diameter. Safety of the irradiation treatment was investigated on 6 samples by measuring pulpal temperature rise. The effect of three topical reagents corresponding to 2% Sodium Fluoride gel (F), Hydroxyapatite nanoparticles (HA) and an equal mix of F and HA (HAF) on dentinal tubule occlusion was evaluated and compared with the laser irradiation.

RESULTS

In all examined cases, laser irradiation at a fluence of 0.81 J/cm2 resulted in a temperature increase less than 3 °C which is safe, and no surface cracking was observed. There is a threshold pulse fluence of 0.27 J/cm2 above which, laser produced surface melting. At a pulse fluence of 0.81 J/cm2 a layer of recast of melted dentin was formed. Under this layer, peritubular dentin melting and occluding of the dentinal tubules was observed. Application of either F or HA or HAF did not produce visible occlusion effect on open tubules after washing and microbrushing with excess distilled water.

CONCLUSIONS

9.3 μm CO2 laser irradiation on extracted human molar dentin at pulse fluence of 0.81 J./cm2 resulted in tubule area reduction by 97% without rising pulpal temperatures to unsafe levels.

Combined Effects of Glutaraldehyde-based Desensitizer and Nd: YAG Laser on Dentinal Tubules Occlusion

AIM

The aim of this study was to assess the impact of Nd:YAG laser, glutaraldehyde-based desensitizer (GD), or their combination on occluding dentinal tubules.

MATERIALS AND METHODS

Fifty dentin samples were obtained from non-carious human third molars and randomly divided into five groups (n = 10): (1) Control group treated with 37% phosphoric acid, (2) GD group, (3) Nd:YAG laser group (1064 nm, 100 µs, 10 Hz, 300 µm fiber, 1 W power, 100 mJ energy, and 85 J/cm2 energy density), (4) GD followed by Nd:YAG laser group, and (5) Nd:YAG laser followed by GD group. Scanning electron microscopy (SEM) was used to capture five images from each sample for analysis of dentinal tubules using Image J software. SEM/EDX elemental analysis was performed to determine the main mineral contents. Data analyzed using one-way ANOVA and Tukey's post hoc test for statistical comparisons.

RESULTS

Laser and combination groups showed a significant decrease in dentinal tubule counts compared with the control and GD groups (p < 0.0001). There were no significant differences in open dentinal tubule counts between the control and GD groups, as well as between the laser and combination groups. However, significant differences were observed in the total area, average size of the tubules, and percentage area between the control group and the treatment groups (GD, laser, GD + laser, laser + GD). No significant difference was found in the Ca/P ratio between the tested groups.

CONCLUSION

The use of Nd:YAG laser alone or in combination with GD was more effective in occluding dentinal tubules compared to GD alone.

CLINICAL SIGNIFICANCE

This study has shown that Nd:YAG laser alone and in combination with GD has superior dentinal tubule occlusion in vitro. Its clinical use in the treatment of dentinal hypersensitivity may overcome the drawback of conventional treatment approaches for dentin hypersensitivity needing repeated applications to achieve continuous relief from pain since acidic diet and toothbrushing result in the continuing elimination of precipitates and surface coatings. How to cite this article: Alzarooni AH, El-Damanhoury HM, Aravind SS, et al. Combined Effects of Glutaraldehyde-based Desensitizer and Nd: YAG Laser on Dentinal Tubules Occlusion. J Contemp Dent Pract 2024;25(1):52-57.

The effect of combination treatment of CO2-laser irradiation and tetracalcium phosphate/dicalcium phosphate anhydrate on dentinal tubules blockage: an in vitro study

The aim of this study was the evaluation of the in vitro efficacy of a carbon dioxide (CO2) laser, a tetracalcium phosphate/dicalcium phosphate anhydrate (TP/DP) desensitizer and the combination of the desensitizer and additional CO2 laser irradiation as a treatment modality for cervical dentin hypersensitivity. A total of 48 dental specimens, prepared from extracted human premolars and molars, were divided into four groups: a control group, a TP/DP desensitizer paste group, a CO2 laser (10.600-nm wavelength) group, and a paste and laser group. The specimens were coated with nail varnish except in the marked area and were then immersed in 2% methylene blue dye for 1 h. The specimens were then washed, dried, and cut longitudinally. Thereafter, photos of 40 dentin specimens were taken and evaluated. The area of penetration was assessed and reported as percentage of the dentin surface area. Additionally eight dental specimens were examined with the aid of a scanning electron microscope and evaluated. Significant differences in the penetration depth were found for all experimental groups compared to the control group. The lowest penetration area was detected in the paste-laser group (16.5%), followed by the laser (23.7%), the paste (48.5%), and the control group (86.2%). The combined treatment of the CO2 laser and a TP/DP desensitizer was efficient in sealing the dentinal surface and could be a treatment option for cervical dentin hypersensitivity.

Comparative Efficacy of Diode, Nd:YAG and Er:YAG Lasers Accompanied by Fluoride in Dentinal Tubule Obstruction

Introduction: Recently, the management of dentin hypersensitivity by lasers has gained special attention. This study aimed to assess and compare the efficacy of the 980 nm diode, Nd:YAG and Er:YAG lasers accompanied by fluoride in dentinal tubule obstruction. Methods: Twenty sound single-rooted human teeth were used for this invitro study. Forty dentinal discs were prepared of the roots and etched with 6% citric acid. One layer of fluoride varnish was applied over their surface. The sections were randomly allocated into 4 groups. The control group received no laser irradiation. Group 2 underwent 980 nm diode laser irradiation with 0.5 W power. Group 3 underwent Nd:YAG laser irradiation with 0.5 W power and group 4 underwent Er:YAG laser irradiation with 0.5 W power. All samples were then inspected under a scanning electron microscope, and the number of obstructed dentinal tubules and the diameter of open dentinal tubules in the field were determined. One-way ANOVA and Tukey's test were used for data analysis at a significance level of 0.05. Results: All three laser types decreased the number of open dentinal tubules significantly compared to the control group (P<0.05). No significant difference was noted in dentinal tubule obstruction between the three laser groups (P>0.05). The diameter of open tubules in the three laser groups did not show a significant difference from that in the control group. Conclusion: All three types of lasers evaluated in this study can effectively obstruct the dentinal tubules.

Dentinal tubule sealing effects of 532-nm diode-pumped solid-state laser, gallic acid/Fe3+ complex, and three commercial dentin desensitizers

The purpose of this study was to compare dentinal tubule sealing effects of a 532-nm diode-pumped solid-state (DPSS) laser, gallic acid/Fe³⁺ complex, and three commercially available dentin desensitizers. Human premolars (n = 44) extracted for orthodontics had standardized cervical cavities prepared, etched (37% phosphoric acid) and randomly assigned to either a control (n = 4), or one of five treatment groups (n = 8/group). Desensitizing treatments were either a 532-nm DPSS laser, gallic acid/Fe³⁺ complex, oxalate-based Super Seal™ (SS), DIO™ Enamel Coating Pen Pro Tooth (Dio), or adhesive-type Hybrid Coat™ (HC). Dentinal fluid flow (DFF) was monitored continuously in real time during the application of each desensitizing agent, by using a nanoliter-scaled fluid flow-measuring device. Following treatment, morphological changes on dentinal surfaces and within tubules were observed by scanning electron microscopy (SEM). DFF rates were significantly reduced after treatment in all experimental groups (P < 0.05), except SS (P > 0.05). The gallic acid/Fe³⁺ complex reduced DFF rates the most, and significantly (P < 0.05) more than the three commercial dentin desensitizers. There were no significant differences in DFF reduction rates between the gallic acid/Fe³⁺ complex and the DPSS laser groups (P > 0.05). There were no significant differences in DFF reduction rates among the three commercial dentin desensitizers (P > 0.05). SEM examination of treated dentin showed that the degree of occlusion of dentinal tubules correlated closely with the corresponding reduction in DFF rates. The gallic acid/Fe³⁺ complex and 532-nm DPSS laser were superior to other desensitizing methods in occluding dentinal tubules and reducing DFF rates.