In Vitro Comparison Of Fluoride Gel Alone and in Combination With Er,Cr:YSGG Laser on Reducing White Spot Lesions in Primary Teeth

Comparative evaluation of fluoride-free remineralization agents with and without Er,Cr:YSGG laser on artificial enamel remineralization

This study aimed to evaluate the efficacy of fluoride-free remineralizing agents in initial enamel caries, with and without combined Er,Cr:YSGG laser application. The remineralization effect of various agents and their combinations on artificial initial caries was investigated using 10 experimental groups (n = 7): NC, negative control; PC, positive control; TM, calcium-phosphate compounds (CPP-ACP); TD, theobromine-containing toothpaste; RG, ROCS® remineralizing gel; L, Er,Cr:YSGG laser (2780 nm; 0.25 W; repetition rate, 20 Hz; pulse duration, 140 μs; tip diameter, 600 μm; without air/water cooling); L + fluoride toothpaste; L + TM; L + TD; and L + RG. The demineralized bovine enamel specimens were subjected to an 8-day pH cycle by daily application of the remineralizing agents and laser therapy once prior to the pH cycle and paste application. The enamel samples underwent the Vickers surface microhardness test, and one sample per group was analyzed with scanning electron microscopy. The Kruskal Wallis test was used to compare the microhardness recovery percentage (SMHR%) for each group, and multiple comparisons were made with the Dunn test. Groups L (p = 0.003), RG (p = 0.019), L + TM (p < 0.001), L + fluoride toothpaste (p = 0.001),and L + RG (p = 0.036) exhibited significant increase in SMHR%. The tested remineralizing agents exhibited no statistically significant difference in effect when used alone and in combination with Er,Cr:YSGG laser. Combined application of Er,Cr:YSGG laser and ROCS® remineralization gel effectively promoted enamel remineralization, while use of CPP-ACP and fluoride toothpaste alone was ineffective. Theobromine-containing toothpaste exhibited the least SMHR%. Long-term evaluation of these agents is recommended.

Application of laser on enamel surface with three types of bioactive glasses-based resin infiltrants: An in vitro study

OBJECTIVE

The study aimed to evaluate and compare the surface micro-hardness, roughness, color, and morphology of enamel after Er,Cr:YSGG laser irradiation, followed by application of three types of bioactive glasses-based resin infiltrants, and the samples groups were challenged with the pH cycle.

METHODOLOGY

Experimental photoactivated resin infiltrants were synthesized using dimethacrylate resins, whereby three different types of bioactive glasses (BGs), i.e., 45S5, fluoridated-BG (F-BG), and borosilicate-BG (B-BG), were incorporated into the resin system. Initially, white spot lesions were created artificially on the toosth enamel surface, then irradiated with Er,Cr:YSGG laser. Then, the resin-only and BG-based resins were infiltrated on the enamel surface. All samples were pH challenged for 14 days, and the micro-hardness, surface roughness, surface morphology, and color stability (ΔE) analyses were conducted before and after the 14 days pH challenge.

RESULTS

After laser irradiation, the micro-hardness was significantly high with 45S5 group compared to resin-only (p = 0.021), F-BG (p = 0.042), and B-BG (p = 0.001) groups. After the pH challenge, the micro-hardness values for all groups were reduced significantly (p ≤ 0.05). The surface roughness was least with the resin-only group and showed a non-significant difference with F-BG (p = 0.34) and significant differences with both B-BG (p = 0.005), and 45S5 (p = 0.010) groups. After the pH cycle, the roughness of all groups was increased significantly (p ≤ 0.05), except B-BG group showed a non-significant difference (p = 0.528). The B-BG group showed significantly high ΔE between day 0 and baseline compared to resin-only (p = 0.0008), F-BG (p = 0.017), and 45S5 (p = 0.029), whereas between day 14 and baseline, the lowest ΔE value was observed for B-BG (14.2 ± 2.10) and maximum for the resin-only (20.57 ± 2.47) group. The SEM images showed pitting on the surface of all resin infiltrant groups after 14 days of pH challenge.

CONCLUSION

The morphological difference was observed after the laser irradiation on the enamel surface. The differences in micro-hardness, surface roughness, and color were observed after the application of experimental resin infiltrants and significant differences were observed after the pH challenge.

Remineralization effects of Er,Cr:YSGG and/or bioactive glass on human enamel after radiotherapy-an in vitro study

The aim was to evaluate the effects of Er,Cr:YSGG and/or bioactive glass 45S5 (BG) on the chemical and physical properties of enamel after radiotherapy. Third molar crowns were cut in half (buccal-lingually), and the mid part of the labial/oral surface was subjected to different protocols. All samples were treated with standard 70 Gy. After radiotherapy, enamel was treated with either Er,Cr:YSGG (2780 nm; pulse 60 μs) and BG or only BG, and control samples were kept in deionized water. Vickers microhardness, scanning electron microscopy (SEM), and characteristic X-ray spectroscopy (EDS) were performed before, after radiotherapy, and after treatment. Analysis of variance (ANOVA) was used. A significant drop in enamel microhardness was observed after radiotherapy (p < 0.001). After Er,Cr:YSGG and BG or BG alone, there was a significant increase in microhardness (p < 0.001), which was on average significantly higher compared to the initial measurements for Er,Cr:YSGG with BG (p < 0.001), but not observed in BG alone (p = 0.331). After radiotherapy, SEM showed increased surface roughness with eroded prisms. Er,Cr:YSGG and BG or BG alone both showed disorderly packed glass particles on the enamel surface. Radiotherapy noticeably reduced the concentrations of calcium and phosphorus. Er,Cr:YSGG and BG treatment increased the concentrations of calcium, sodium, phosphorus, and silicate. BG treatment alone increased the concetration of calcium and phosphorus. Directly induced radiotherapy led to potential damage of enamel, but afterwards treatment with Er,Cr:YSGG laser and BG resulted in a higher increase of enamel microhardness compared to BG alone, reflecting in a possible better remineralization effect.

In vitro controlled elemental analysis to evaluate the combined effect of acidulated phosphate fluoride with Er:YAG and diode lasers

Background

Acidulated phosphate fluoride (APF) application is used for dental caries prevention. Combining APF with different laser wavelengths increases acid resistance in enamel.

Aim

To assess the effects of Er:YAG (2940 nm) laser and diode (940 nm) laser after the application of APF on morphology and mineral content of enamel surfaces of human teeth in vitro.

Materials and Methods

Twenty (20) freshly extracted third molar crowns were collected and split longitudinally into halves. Ten (10) halves were given to each of the following groups: group 1 (control), group 2 (application of 1.23% APF gel only), group 3 (diode laser; 1 W for 60 sec, contact mode after APF gel), and group 4 (Er:YAG; 80 mJ, 0.8 W, 10 Hz; in pulsed mode for 10 sec after APF gel). Specimens were morphologically examined by scanning electron microscope (SEM), and mineral content was analysed by energy dispersive X-ray (EDX). Collected data were statistically analysed by ANOVA.

Results

Morphologic results were superior in group 3 followed by group 2 and group 1 with the least change in group 4. EDX of calcium (Ca), phosphorous (P), and Ca/P ratio weight % showed the highest value with no statistical significance between groups 2 and 1, and higher with statistical significance in groups 3 and 4 in descending order. Carbon weight % showed highest results in group 4 then 3, 2, and 1. Fluoride weight % showed highest statistical results in group 4 then 2, 3, and 1.

Conclusion

The diode laser showed superior morphological results after APF application compared to the Er:YAG laser. The Er:YAG increased fluoride absorption on outer enamel surfaces.

Effect of Er:YAG Laser Irradiation and Acidulated Phosphate Fluoride Therapy on Re-Mineralization of White Spot Lesions

Statement of the Problem:

Studies on the efficacy of erbium laser for enhancement of enamel resistance to acid attacks and its effects on fluoride uptake by the enamel are limited.

Purpose:

This study sought to assess and compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation and application of acidulated phosphate fluoride (APF) gel (alone and in combination) on remineralization of artificial white spot lesions (WSLs).

Materials and Method:

This in vitro, experimental study evaluated 90 buccal and lingual slabs of extracted human premolars. The specimens underwent pH cycling to induce WSLs. They were then randomly divided into 6 groups of caries-free positive control (c+), negative control with WSLs (ws), 1.23% APF gel applied on the enamel (F), Er:YAG laser irradiation (80 mJ, 10 Hz, and 8 J/cm²) of enamel (L), APF gel application followed by laser irradiation (FL), and laser irradiation followed by fluoride gel application (LF). The fluoride ion content of specimens was measured before and after the intervention using a potentiometer. Data were analyzed by ANOVA (p< 0.05).

Results:

APF gel application before/after laser irradiation maximally increased the fluoride uptake by the enamel (p= 0.000). Application of APF gel in group F and laser irradiation in group L increased fluoride uptake by the enamel, compared with groups 1 and 2 (p= 0.000). Laser- treated (L) and APF-treated (F) groups had no significant difference in this respect (p= 0.945). Maximum fluoride concentration was noted in combined laser and fluoride groups (FL=332.07ppm and LF=341.27ppm) with no significant difference between the two (p= 1.000).

Conclusion:

Er:YAG laser irradiation changes the chemical composition of enamel and probably promote its remineralization, especially when combined with APF gel application, which highlights its cariostatic potential.

Effect of Er,Cr:YSGG Laser on the Prevention of Primary and Permanent Teeth Enamel Demineralization: SEM and EDS Evaluation

Objective: To evaluate in vitro the effect of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on resistance of primary and permanent human enamel to demineralization using water cooling and fluoride coapplication as variable parameters. Methods: Enamel specimens were prepared from extracted primary and permanent teeth (n = 225 each). The specimens were separated into 15 subgroups (n = 15/group) based on laser application at three different power settings (0.25, 0.50, and 0.75 W), laser application with and without water cooling, and application of acidulated phosphate fluoride (APF) gel before laser treatment. Morphological changes were assessed with scanning electron microscopy (SEM), and the specimens' chemical contents were determined with energy-dispersive X-ray spectroscopy. Results: In both the primary and permanent teeth, the highest Ca and P content was observed in the noncooled 0.75 W laser group (p < 0.05), irrespective of APF pretreatment (p > 0.05). The Ca and P content for the noncooled APF +0.75 W laser group was lower than that for the APF group and the noncooled 0.75 W laser group. For both dentitions, the F mass content for the APF+laser groups was significantly higher than laser-only groups (p < 0.05). Under SEM, both the primary and permanent enamel exhibited cracks, craters, and surface roughness without water cooling, consistent with increased power output. Conclusions: Er,Cr:YSGG laser application at 0.75 W without water cooling increased enamel resistance to demineralization. Compared with topical APF application, Er,Cr:YSGG laser application barely improved enamel resistance against demineralization, and coapplication did not result in a synergistic effect.

Microshear Bond Strength of Composite Resin to Enamel Treated With Titanium Tetrafluoride and the Carbon Dioxide Laser (10.6 µm): An In Vitro Study

Introduction: The present study aims to assess the microshear bond strength (µSBS) of composite to enamel treated with titanium tetrafluoride (TiF4 ) and CO₂ laser irradiation. Methods: Fifteen human molars were sectioned and their enamel surfaces were abraded. The sections were randomly assigned to 5 groups (n=15): (CO); control group, (AP); treated with 1.23% acidulated phosphate fluoride (APF) for 4 minutes, (Ti); 4% TiF₄ for 1 minute, (L+AP); CO₂ laser irradiation (10.6 µm wavelength, 1 W peak power, 10 ms pulse duration, 500 ms repetition time, 0.2 mm beam spot size at the tissue level, 2 cm distance of handpiece tip to tissue surface (DSE, South Cores) followed by 1.23% APF, and (L+ Ti); 10.6μm CO₂ laser irradiation followed by 4% TiF₄ for one minute. Using Tygon tubes, Z250 (3M/ESPE) composite was bonded to the surface of the samples. The µSBS of composite to enamel was measured using a microtensile testing machine after 500 thermal cycles. The data were analyzed by one-way ANOVA and the Tukey HSD test (P <0.05). Results: The mean µSBS was 20.66, 20.21, 13.44, 23.01, and 10.16 MPa in CO, AP, Ti, L+AP, and L+Ti groups respectively. Significant differences were observed between CO and Ti (P =0.026) and also CO and L+ Ti (P <0.0001). Conclusion: The application of TiF₄ per se and after CO₂ laser irradiation on enamel decreased the µSBS of composite to enamel; on the other hand, APF alone and after laser irradiation did not have any adverse effect on the µSBS of composite to enamel.

Thermal, morphological, and spectral changes after Er, Cr:YSGG laser irradiation at low fluences on primary teeth for caries prevention

The aim of this study was to determine the temperature increase in the pulp chamber and possible thermal effects on molecular structure of primary teeth during the irradiation with Er,Cr:YSGG laser. Primary central incisors were divided into three groups (n = 20). Labial surfaces in each group were irradiated by Er,Cr:YSGG laser within different power and frequencies as following groups: I: 0.25 W, 20 Hz, II: 0.50 W, 20 Hz, III: 0.75 W, 20 Hz. A thermocouple was placed inside the pulp chamber so that the temperature increments were recorded during the enamel irradiation. Morphological changes of enamel surfaces were experimentally evaluated by SEM. Fourier-transform infrared spectroscopy and RAMAN analyses were carried out to determine the differentiations in the molecular structure. The experimental results obtained were analyzed statistically by means of one-way analysis of variance. Statistically significant differences were detected between groups (p < .05). Group III exhibited the highest values for the temperature parameters. Besides, the conical craters, cracks, and formation of ablation areas were observed for all the groups. Also, it was obtained that the hydroxyapatite lost the hydroxyl ions due to the thermal effect of the laser. Temperature rise throughout the Er,Cr:YSGG laser irradiation for prevention of primary enamel demineralization presented a positive correlation with the laser output power level. The formations of adverse morphological and spectral changes were detected on the surface of teeth after the laser application. On this basis, the Er,Cr:YSGG laser applications should be treated with much more caution considering enamel surface and pulpal tissues in primary teeth.

Effect of the usage of Er,Cr:YSGG laser with and without different remineralization agents on the enamel erosion of primary teeth

The aim of the present study was to evaluate the effects of different remineralization agents associated with erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) (0.5 W power, 20 Hz frequency, 60% water, 40% air, 25 mJ pulse energy, 8.84 J/cm² fluence, 60 μs pulse duration, 600 μm tip diameter, and an approximate 1-1.5 mm distance to the target) laser irradiation on erosion induced by the consumption of carbonated drinks in human primary enamel. There were 8 groups and 10 primary teeth in each g0roup. The distribution was as follows: group 1, casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF); group 2, Er,Cr:YSGG laser+CPP-ACPF; group 3, fluor varnish; group 4, Er,Cr:YSGG Laser+fluoride varnish; group 5, ROCS® medical mineral gel; group 6, Er,Cr:YSGG laser + ROCS® medical mineral gel; group 7, Er,Cr:YSGG laser; and group 8, artificial saliva. The samples in the groups were submerged in artificial saliva and acid twice a day for 6 s at 6-h intervals and were then exposed to an erosion cycle 15 times. In the groups in which the Er,Cr:YSGG laser was applied in combination with the remineralization agents, the laser application was made first, and then the remineralization agents were applied for 4 min in each group. The Friedman and Wilcoxon signed-rank tests and the Bonferroni correction were used in statistical analyses, and the significance level was taken as p < 0.05. According to the results, all agents had a statistically significant difference (groups 1, 2, 3, 4, and 6: p = 0.005, p < 0.017; groups 5 and 7: p = 0.007, p < 0.017) between BL-RM periods. However, all agents had a statistically significant remineralization effect on primary teeth enamel (groups 1, 2, 3, 6, and 7: p = 0.005, p < 0.017; group 4: p = 0.011, p < 0.017) except that group 5 (p = 0.074, p < 0.017) between DM-RM periods. The coadministration of an agent with the laser did not make any difference at a statistical level (p = 0.804, p > 0.05). The results were supported by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. As a result of this study, CPP-ACPF had a notable impact in terms of the remineralization effect on eroded enamel, and the Er,Cr:YSGG laser alone may be an alternative method, which may be related to the modified hydroxyapatite structure, 38.5% H_0.56Ca_4.56O₁₃P₃Y_0.44, that was determined in XRD analysis.

Laser-assisted prevention of enamel caries: a 10-year review of the literature

Since the invention of lasers in dentistry, investigations in caries prevention by the use of laser radiation have been proposed. There are several mechanisms stated for this purpose such as photothermal and/or photochemical interaction processes with the enamel. Alone or in conjugation with topical fluoride application, this treatment modality may improve enamel acid resistance in high-caries-risk populations. Data collection was done by searching the keywords caries, prevention, and laser in PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar. Lasing protocols of the collected literature and their effectiveness as well as examination methods used to verify treatment outcomes have been evaluated. One hundred eighteen publications were found for the last 10 years. The wavelengths investigated for caries prevention are mainly located in the near and the mid-infrared spectral range. In the evaluated period of time, investigations using CO₂; Er:YAG; Er,Cr:YSGG; Er:YLF; fundamental, second, and third harmonic generations of Nd:YAG; diodes; and argon ion lasers were found in the databases. Accounting for 39% of the literature, CO₂ laser was the most examined system for this purpose. Reviewing the literature in this narrative review showed that all laser systems presented a positive effect in varying degrees. Laser irradiation could be an alternative or synergistic to topical fluoridation for enamel caries prevention with longer lasting effect. Further research should be focused on selecting proper laser settings to avoid damage to enamel and developing effective evidence-based clinical protocols.

Effect of Er,Cr:YSGG on Remineralization Using CPP - ACPF (MI - Paste Plus) after Enamel Erosion Caused by Carbonated Soft Drink in Primary Teeth: In-Vitro Study

BACKGROUND:

Erosion is a widespread phenomenon with higher predilection in primary dentition.

AIM:

The aim of the present study is to assess the remineralising effect of Er,Cr:YSGG laser application combined with CPP-ACPF after erosive demineralisation by Coca-Cola in primary teeth.

METHODS:

Fifty teeth (n = 10) were divided into; Group I: Artificial saliva, (Saliva natural, Medac, UK), Group II: CPP-ACPF (MI Paste Plus, GC Corp, USA), Group III: Er,Cr:YSGG (Waterlase iPlus, USA), Group IV: CPP-ACPF + Er,Cr:YSGG, Group V: Er,Cr:YSGG + CPP-ACPF. Teeth were immersed in Coca-Cola for 10 min, 5 times/day for 5 days. DIAGNOdent (DD) measurements were taken before and after the experiment.

RESULTS:

There was a significant increase in DD readings after erosive-treatment cycles in all test groups. The highest reading was in samples immersed in artificial saliva, and the lowest was in those subjected to combined CPP-ACPF and Er,Cr:YSGG laser application, regardless of the sequence used. There was no significant difference between samples immersed in artificial saliva, and after CPP-ACPF application. Similarly, there was no significant difference between samples treated by combined treatment of CPP-ACPF and Er,Cr:YSGG application. However, there was a significant difference between samples immersed in artificial saliva or treated with CPP-ACPF application and those subjected to combined treatment CPP-ACPF along with Er,Cr:YSGG.

CONCLUSION:

Combining Er,Cr:YSGG laser and CPP-ACPF paste significantly increased enamel remineralisation, regardless of the sequence implemented. Saliva naturally and CPP-ACPF application had a comparable effect on remineralisation.