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.

The effect of laser therapy for the treatment of dentin hypersensitivity on surface roughness and bacterial adhesion.

The aim of the study was to measure the degree of dentine surface roughness caused by five distinct lasers used to treat dentine hypersensitivity, as well as to evaluate the subsequent bacterial colonization on these irradiated surfaces. Sixty human maxillary premolar teeth without caries or restoration which were extracted for periodontal reasons were used in this study. Five different types of lasers were applied to the root dentin surface. Tested samples were divided into six groups of 10 samples each; control, diode (810 nm), diode (980 nm), Nd: YAG, Er: YAG, and Er, Cr: YSGG laser groups. The arithmetic mean of the surface roughness values (Ra) and the average roughness over a measurement area (Sa) were measured pre- and post-application using any of the laser types. Swab samples were then collected from the dentin surface. Following a 24-hour incubation period at 37 °C, the colony forming units were counted using a stereoscope. The results demonstrated a statistically significant difference in the surface roughness values pre- and post-application (Ra and Sa, respectively) in the Er, Cr: YSGG laser group (p = 0.037,p = 0.007). No significant difference was observed in the other groups (p > 0.05). There was no statistically significant difference in the number of bacterial colonies observed between the test and control groups. Diode and Nd: YAG lasers showed either a decrease or no change in surface roughness; however, the hard tissue lasers (Er: YAG, Er, Cr: YSGG) showed an increase. The Er: YAG and Nd: YAG laser groups exhibited decreased bacterial adhesion compared to the other groups.

EFFECT OF LOW-LEVEL DIODE LASER ON DENTIN TOPOGRAPHY AND SYMPTOMATIC NONCARIOUS CERVICAL LESIONS PRIOR TO COMPOSITE RESTORATIONS: A SPLIT-MOUTH RANDOMIZED CONTROLLED TRIAL.

OBJECTIVES: This study assessed alterations in sensitivity among symptomatic noncarious cervical lesions (NCCLs) following the application of 3 low-level diode laser wavelengths before composite restoration. It analyzed the changes in dentin topography using a scanning electron microscope (SEM). MATERIALS AND METHODS: Nine patients with 36 NCCLs were randomly assigned intra-individually to 4 groups based on the laser wavelength: laser simulation, 445 nm, 660 nm, and 970 nm. Cavity preparation, irradiation, and composite restoration were performed for each lesion. Sensitivity to cold stimuli was recorded using a visual analog scale (VAS) before the intervention (baseline) and at 1 day, 14 days, 1-, 3-, and 6-month. Pulp sensibility was recorded using an electrical pulp tester (EPT) at baseline, before treatment, and at 3- and 6-month. Additionally, an in vitro examination was performed on 12 extracted human molars to yield 12 dentin discs. Each disc was randomly divided into 4 quadrants to receive the same laser wavelengths to determine the diameters of the tubules using SEM. Results were analyzed statistically for clinical studies by the Friedman test, while ANOVA (RM-ANOVA) was conducted in-vitro, followed by the Bonferroni test in the case of significance (P < .05). RESULTS: VAS readings decreased across all groups, with a significant decrease observed for 660 nm and 970 nm from 14 days to 6-month, while at 445 nm there was a significant decrease at 6-month compared to the control (P < .05). EPT showed a significant decrease in pain threshold levels at 660 nm and 970 nm at 3- and 6-month, while 445 nm showed a significant decrease at 6-month compared to the control (P < .05). The mean tubular diameter at 445 nm decreased, with no significant difference from the control, whereas a significant decrease was found at 660 nm and 970 nm compared to the control (P < .05). CONCLUSIONS: Prior to composite restoration in symptomatic NCCLs, diode lasers with a wavelength of 660 nm showed the highest reduction in sensitivity, followed by 970 nm, whereas 445 nm diode lasers showed the least reduction. Additionally, diode lasers with wavelengths of 660 and 970 nm reduced the width of the dentinal tubules (DT) without inducing melting, as viewed under SEM.

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.

Er:YAG laser therapy in combination with GLUMA desensitizer reduces dentin hypersensitivity in children with molar-incisor hypomineralization: a randomized clinical trial.

This study aimed to investigate the effectiveness of erbium-doped yttrium garnet (Er:YAG) laser and GLUMA desensitizer for dentin hypersensitivity in teeth affected by Molar-Incisor Hypomineralization (MIH). One hundred twenty children were randomly allocated to four groups: the control (Co) group, the desensitizer (De) group, the laser (La) group, and the laser + desensitizer (La + De) group. Outcome measures included Visual Analogue Scale (VAS) and 14-item Oral Health Impact Profile (OHIP-14) evaluation. For mean VAS scores, a significant reduction was found over time in all groups. Co and De groups, Co and La groups, Co and La + De groups, De and La + De groups, and La and La + De groups differed significantly (p < 0.05). For mean scores in all dimensions of OHIP-14 after treatment 6 months, the La + De group was significantly lower (p < 0.001). The La + De groups and the La groups as well as the La + De groups and the De groups differed significantly in total OHIP, functional limitation, physical disability, and psychological disability (p < 0.05). Physical pain between the La + De groups and the La groups and handicap between the La + De groups and De groups differed significantly (p < 0.05). The mean values of each dimension differed significantly between the group Co and the La + De group (p < 0.0001). Combination therapy of Er:YAG laser and GLUMA desensitizer had greater desensitizing effects and oral health-related quality improvement of life, which might be an effective alternative treatment in dentin hypersensitivity in MIH children.

Evaluation of dentinal tubule occlusion and pulp tissue response after using 980-nm diode laser for dentin hypersensitivity treatment.

OBJECTIVES: To evaluate the effectiveness of the 980-nm diode laser for dentinal tubule occlusion, measure the intrapulpal temperature, and investigate the dental pulp response. MATERIALS AND METHODS: The dentinal samples were randomly divided into G1-G7 groups: control; 980-nm laser irradiation (0.5 W, 10 s; 0.5 W, 10 s × 2; 0.8 W, 10 s; 0.8 W, 10 s × 2; 1.0 W, 10 s; 1.0 W, 10 s × 2). The dentin discs were applied for laser irradiation and analyzed by scanning electron microscopy (SEM). The intrapulpal temperature was measured on the 1.0-mm and 2.0-mm thickness samples, and then divided into G2-G7 groups according to laser irradiation. Moreover, forty Sprague Dawley rats were randomly divided into the laser-irradiated group (euthanized at 1, 7, and 14 days after irradiation) and the control group (non-irradiated). qRT-PCR, histomorphology, and immunohistochemistry analysis were employed to evaluate the response of dental pulp. RESULTS: SEM indicated the occluding ratio of dentinal tubules in the G5 (0.8 W, 10 s × 2) and G7 (1.0 W, 10 s × 2) were significantly higher than the other groups (p < 0.05). The maximum intrapulpal temperature rises in the G5 were lower than the standard line (5.5 ℃). qRT-PCR showed that the mRNA expression level of TNF-α and HSP-70 upregulated significantly at 1 day (p < 0.05). Histomorphology and immunohistochemistry analysis showed that, compared with the control group, the inflammatory reaction was slightly higher at the 1 and 7 days (p < 0.05) and decreased to the normal levels at 14 days (p > 0.05). CONCLUSIONS: A 980-nm laser at a power of 0.8 W with 10 s × 2 defines the best treatment for dentin hypersensitivity in terms of compromise between the efficacy of the treatment and the safety of the pulp. CLINICAL RELEVANCE: The 980-nm laser is an effective option for treating dentin sensitivity. However, we need to ensure the safety of the pulp during laser irradiation.

Efficacy of near infrared dental lasers on dentinal hypersensitivity: a meta-analysis of randomized controlled clinical trials.

Conventional therapies have aimed to try to help individuals suffering with dentine hypersensitivity (DH/DHS). A relatively new approach, laser therapy claims to be beneficial while having immediate and long-lasting effect. Therefore, our analysis aims to explore the immediate and 1-month efficacy of near-infrared laser (NIR) therapy in treating dentinal hypersensitivity. A systematic literature search conducted in databases, and analysis was undertaken utilizing a meta-analysis approach. Randomized controlled clinical trials comparing near-infrared lasers and placebo/no treatment in patients (> 18 years) were included. The risk of bias for included studies was assessed using Cochrane RoB tool (for randomized studies). Random effects meta-analyses model of standardized mean differences and 95% confidence intervals were performed using RevMan 5.4 software. A comprehensive electronic and manual search yielded a total of 1081 potential articles. Following the implementation of the inclusion and exclusion criteria, a total of 6 studies were included in the analysis. Near-infrared laser therapy led to statistical significant reduction in immediate and 1-month follow-up VAS (visual analog scale) scores compared to placebo/no treatment (p < 0.05). Statistical heterogeneity across the studies was high (I2-96%). The findings suggest that near-infrared laser therapy does have a significant immediate effect in reducing dentine hypersensitivity compared to placebo/no treatment. Furthermore, this effect is not diminished and endured at 1-month follow-up.

Use of infrared photobiomodulation with low-level laser therapy for reduction of bleaching-induced tooth sensitivity after in-office bleaching: a double-blind, randomized controlled trial.

The purpose of this study is to evaluate the use of infrared photobiomodulation with low-level laser therapy (PBM) to reduce bleaching-induced tooth sensitivity (TS) after in-office bleaching. Eighty-three participants were randomized in blocks into two groups. In the experimental group, the patients received an application after each session of in-office bleaching (35% hydrogen peroxide, 1 × 50 min; 2 sessions with 1-week interval), while the laser application was simulated in the control group. The PBM system was operated in continuous mode, using 3 J of energy. A dose of 100 J/cm2 was applied for 30 s with 808 nm (100 mW of power) in the middle third of the crown. The risk and intensity of TS were recorded immediately after bleaching, 1 h, 24 h, and 48 h after each bleaching session, with a visual scale analog (0-10) and a five-point numerical scale (0-4). The color was recorded at the beginning, weekly, and 1 month after the end of the bleaching (VITA Classical, VITA Bleachedguide, and digital spectrophotometer). The risk of TS was 98% (95% CI 88 to 99%) for the laser group and 95% (95% CI 83 to 99%) for the control (RR = 1.03; 95% CI 0.94 to 1.12; p = 1.0). Similarly, no difference in the intensity of TS was detected for both pain scales (p > 0.65). Improvement in color change, regardless of the group, was observed (p > 0.15). The application of an PBM did not reduce the risk and intensity of TS when applied after the procedure using the parameters recommended by the manufacturer.Trial registration number and date of registration: RBR-4HCVSG-04/06/2019.

Effect of sodium fluoride varnish, Gluma, and Er,Cr:YSGG laser in dentin hypersensitivity treatment: a 6-month clinical trial.

Dentinal hypersensitivity (DH) is a common clinical condition usually associated with exposed dentinal surfaces. The aim of this study was to study the effect of sodium fluoride varnish, Gluma, and Er,Cr:YSGG laser, in the dentin hypersensitivity treatment. One hundred sixty-five teeth with dentin hypersensitivity in 55 patients were involved in this study. Teeth are divided into five groups based on the received treatment (n = 33): G group: Gluma; F group: sodium fluoride varnish (5%); L group: Er,Cr:YSGG laser (wavelength 2780 nm, frequency 20 Hz, power 0.25 W, energy density 44.3 J/cm2, and pulse width of 150 µs at distance of 1 mm for 30 s) which was followed by Er,Cr:YSGG laser; GL group: Gluma + laser; VL group: both sodium fluoride varnish and Gluma, which are common treatments for hypersensitivity, were selected as control groups. The treatment was performed in one session, and the sensitivity to air spray conditioning was recorded after the treatment, at 15 min, 1 week, 1 month, and 6 months as the VAS. Statistical analysis was performed using SPSS Ver. 21 software. One-way ANOVA was used to compare the VAS between all treatment groups at each time-point. One-way repeated measurements ANOVA (RM-ANOVA) and two-way-repeated measurements ANOVA (RM-ANOVA) were used to compare the hypersensitivity of each group and sensitivity of all treatment groups, respectively. Tukey post hoc test was used to compare the groups pairwise. The hypersensitivity between different groups at before and 15 min after the treatment was not significantly different (P = 0.063). The hypersensitivity of all studied groups was decreased after the treatment. The Er,Cr:YSGG laser, alone or in combination with Gluma, in 1 week, 1 month, and 6 month follow-ups, had significantly reduced the hypersensitivity instead of sodium fluoride varnish. All treatments significantly reduced the dentin hypersensitivity up to 6 months. Er,Cr:YSGG laser alone or in combination with Gluma was more effective than sodium fluoride varnish; however, it was not significantly different from other treatments. In a 6-month follow-up of dentine hypersensitivity treatment, Gluma had a significantly higher effect than sodium fluoride. Trial registration: IRCT20190422043343N1. Registered 19 July 2019.

Photobiomodulation therapy and 3% potassium nitrate gel as treatment of cervical dentin hypersensitivity: a randomized clinical trial.

OBJECTIVES: This randomized controlled trial aimed to evaluate different protocols for dentin hypersensitivity treatment with low-power lasers and desensitizing agents, and the association between low-power lasers and desensitizing agents. MATERIALS AND METHODS: Fifty-four patients (303 teeth) were randomly allocated to three groups: G1, 3% nitrate potassium gel, UltraEZ (n = 17); G2, photobiomodulation therapy (PBM) with a low-level infrared laser (n = 17), 100 mW, spot size of 0.028 cm2, and dose of 1 J per point; and G3, nitrate potassium + PBM (n = 20). Treatments were applied to the buccal cervical region at intervals of 72 h, and all protocols were performed in three sessions. The patients' response to evaporative stimuli was rated using the visual analog scale (VAS). Re-evaluations were performed immediately after each application and 1 week, 1 month, and 3 months after treatment. A two-way repeated measures test and Tukey's post hoc test were used for multiple comparisons (α = 5%). RESULTS: There was a reduction in pain levels at the end of treatment in all groups. There were no significant differences in VAS score changes between the groups immediately after treatment and after the third month, compared to the baseline (p > 0.05). CONCLUSION: Under the limitations of this in vivo study, the proposed three-session protocol was effective in reducing dentin hypersensitivity after 3 months, regardless of the desensitization mechanism used. Conservative and long-term protocols are interesting for the control of pain caused by dentin hypersensitivity. CLINICAL RELEVANCE: The increase in cervical dentin hypersensitivity prevalence warrants easy-to-apply and long-lasting desensitizing protocols for pain control.

Is photobiomodulation (PBM) effective for the treatment of dentin hypersensitivity? A systematic review.

The present study aims to evaluate the current scientific data regarding the effectiveness of photobiomodulation (PBM) in the treatment of dentin hypersensitivity (DH) as an alternative method for pain control. A systematic review was conducted to assess the effectiveness of PBM as treatment for DH. A complete literature search was performed up to October 2016. Searches were conducted using Boolean operators and MeSH terms. References of all selected full-text articles and related reviews were scanned. A total of 280 articles were identified (241 articles were excluded by the title and abstract). Of the 39 articles selected for analysis, 36 were excluded because they presented one or more exclusion criteria. Therefore, three articles were qualified for inclusion in this systematic review. PBM may not lead to adverse effects provided that adequately controlled parameters are followed when treating DH. More consistent studies should be conducted in order to adequately observe the advantageous therapeutic effect of PBM.

The association between Nd:YAG laser and desensitizing dentifrices for the treatment of dentin hypersensitivity.

This study aims to evaluate the association between Nd:YAG laser (with and without a photoabsorber) and two desensitizing dentifrices containing 15% NovaMin or 8% arginine, as potential treatments for dentin hypersensitivity (DH). DH was simulated by EDTA application for 2 min. Specimens were then analyzed with an environmental scanning electron microscope (ESEM) to ensure open dentin tubules (ODT), counted by using ImageJ software. Specimens were randomized into eight groups (n = 10): Laser (L), Laser+Photoabsorber (LP), Arginine (A), Arginine+Laser (AL), Arginine+Laser+Photoabsorber (ALP), NovaMin (N), NovaMin+Laser (NL), and NovaMin+Laser+Photoabsorber (NLP). Laser irradiation was performed with 1 W, 100 mJ, 10 Hz, ≅85 J/cm2; 4 irradiations of 10 s each, with 10 s intervals between them. After treatment, specimens were again analyzed by ESEM and submitted to erosive/abrasive cycling for 5 days. A final ESEM analysis was performed. Data were analyzed with two-way repeated measure ANOVA and Tukey tests (α = 0.05). After treatment, groups N, NL, and NLP presented the lower number of ODT, but they did not different from LP, ALP, and AL. Group A presented the highest number of ODT and it did not differ from group L. Groups L, AL, ALP, and LP presented intermediate results, without differing from each other. After cycling, group A presented the highest number of ODT and did not differ significantly from the other groups, except NLP. None of the associations tested presented better tubule occlusion than NovaMin by itself. Arginine was the only treatment that presented improved tubule occlusion when associated with Nd:YAG laser.

Evaluation of different treatment protocols for dentin hypersensitivity: an 18-month randomized clinical trial.

This randomized and longitudinal in vivo study aimed to assess different protocols for the treatment of dentin hypersensitivity with low-power laser (with different doses), high-power laser, and a desensitizing agent, for a period of 12 and 18 months. The lesions from 32 patients (117 lesions), who were submitted to the inclusion and exclusion criteria, were divided into nine groups (n = 13): G1: Gluma Desensitizer (Heraeus Kulzer), G2: low-power laser with low dose (three points of irradiation in vestibular portion and an apical point 30 mW, 10 J/cm2, 9 s per point with the wavelength of 810 nm, with three sessions with an interval of 72 h), G3: low-power laser with high dose (one point in the cervical area, and one apical point 100 mW, 40 J/cm2, 11 s per point with the wavelength of 810 nm in three sessions with an interval of 72 h), G4: low-power laser with low dose + Gluma Desensitizer, G5: low-power laser with high dose + Gluma Desensitizer, G6: Nd:YAG laser (Power Laser™ ST6, Research® in contact 1.0 W, 10 Hz and 100 mJ, ≈85 J/cm2, with the wavelength of 1064 nm), G7: Nd:YAG laser + Gluma Desensitizer, G8: low-power laser with low dose + Nd:YAG laser, and G9: low-power laser with high dose + Nd:YAG laser. The level of sensitivity of each volunteer was assessed by visual analog scale of pain (VAS) with the aid of air from the triple syringe and exploration probe, 12 and 18 months after treatment. All analyses were performed separately for air and probe stimulus. The level of significance was considered for values of p < 0.05. After statistical analysis, all treatments were shown to be effective in reducing dentinal hypersensitivity, and the results were considered not statistically different from those at 12 months. Therefore, until the 18-month evaluation, it could be said that no statistical differences were observed in the sensitivity levels for all treatments.

The potential of low-power laser for reducing dental sensitivity after in-office bleaching: a case report.

Postoperative sensitivity is one of the most common side effects of in-office bleaching with hydrogen peroxide. Laser phototherapy (LPT) has been suggested as an adjunctive treatment to prevent or minimize tooth sensitivity. This case report aimed to verify the efficacy of LPT in the reduction of sensitivity after in-office bleaching. Tooth bleaching was performed with 35% hydrogen peroxide activated with a hybrid LED-laser device. Immediately after the bleaching treatment, the patient reported dental sensitivity, as measured with a visual analog scale (VAS). To reduce sensitivity, LPT was applied with a 780-nm laser using the following parameters: 70 mW, exposure time of 10 seconds per point of irradiation (middle region of the buccal surfaces of each compromised tooth) in contact mode, energy of 1 J per point. Immediately after LPT, the patient reported a substantially lower level of pain on the VAS. Twenty-four hours after bleaching, the score on the VAS indicated that sensitivity levels had rebounded, and the patient received additional LPT. After 48 hours, the patient reported no dental sensitivity. The results in this patient indicated that irradiation with an infrared low-power laser substantially reduced dental pain generated by bleaching, suggesting that LPT should be considered as an auxiliary method to reduce postbleaching tooth sensitivity.

Effect of low-level laser therapy on tooth sensitivity induced by in-office bleaching.

This study aimed to investigate the effect of low-level laser therapy (LLLT) on tooth sensitivity induced by in-office bleaching. Sixty-six patients enrolled in this randomized clinical trial. Following the in-office procedure with 40% hydrogen peroxide, the participants were randomly divided into three groups. The patients in group 1 received irradiation from a low-level red laser (LLRL; 660 nm, 200 mW, 15 s, 12 J/cm(2)), whereas participants in group 2 were subjected to a low-level infrared laser (LLIL; 810 nm) under similar conditions as in group 1. In group 3 (placebo), the laser treatment was the same as that in groups 1 and 2, but without energy output. The degree of tooth sensitivity was recorded at 1, 24, and 48 h after bleaching using a visual analog scale (VAS). The change in tooth shade was measured 30 days after tooth whitening. The intensity of tooth sensitivity was not significantly different between groups at 1 h after bleaching (p > 0.05). At 24 h after therapy, pain level was significantly lower in the LLIL group compared to the LLRL and placebo groups (p < 0.05). At 48 h after bleaching, VAS scores in the LLIL and LLRL groups were comparable to each other (p > 0.05) and both were significantly lower than that of the placebo group (p < 0.05). There was no significant difference in the efficacy of tooth whitening among groups (p > 0.05). LLLT with an infrared diode laser could be recommended as a suitable strategy to reduce the intensity of tooth sensitivity after in-office bleaching.

Applications of Light Amplification by Stimulated Emission of Radiation (Lasers) for Restorative Dentistry.

Light amplification by stimulated emission of radiation (laser) has been used widely in a range of biomedical and dental applications in recent years. In the field of restorative dentistry, various kinds of lasers have been developed for diagnostic (e.g. caries detection) and operative applications (e.g. tooth ablation, cavity preparation, restorations, bleaching). The main benefits for laser applications are patient comfort, pain relief and better results for specific applications. Major concerns for using dental lasers frequently are high cost, need for specialized training and sensitivity of the technique, thereby compromising its usefulness particularly in developing countries. The main aim of this paper is to evaluate and summarize the applications of lasers in restorative dentistry, including a comparison of the applications of lasers for major restorative dental procedures and conventional clinical approaches. A remarkable increase in the use of lasers for dental application is expected in the near future.

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.

A randomized clinical trial of the effect of low-level laser therapy before composite placement on postoperative sensitivity in class V restorations.

This study aimed to investigate the efficacy of low-level laser irradiation when applied just before placement of resin composite on reducing postoperative sensitivity of class V lesions. In this randomized clinical trial, 31 patients with 62 class V cavities were included (two teeth in each participant). The teeth were randomly assigned into laser and placebo groups. After cavity preparation, the teeth in the experimental group were subjected to irradiation from a low-power red laser (630 nm, 28 mW, continuous wave, 60 s, 1.68 J), which was applied for 1 min on the axial wall of the cavity. In the control group, the same procedure was performed but with laser simulation. Then, a self-etch adhesive was applied and the cavities were restored with a microhybrid resin composite. Before treatment and on days 1, 14, and 30 after treatment, tooth sensitivity to a cold stimulus was recorded using a visual analogue scale. Data were analyzed by Friedman and Wilcoxon signed-rank tests (p < 0.05). Pain scores after restorative procedures were significantly lower in the laser group compared to the placebo application (p < 0.05). Although both groups experienced a significant improvement in pain and discomfort throughout the follow-up periods (p < 0.001), the changes in visual analogue scale (VAS) scores between baseline and each follow-up examination were significantly greater in the laser than the placebo group (p < 0.05). Low-level laser therapy (LLLT) before placement of resin composite could be suggested as a suitable approach to reduce postoperative sensitivity in class V restorations.

Evaluation of potassium binoxalate gel and Nd:YAG laser in the management of dentinal hypersensitivity: a split-mouth clinical and ESEM study.

Dentinal hypersensitivity is one of the oldest recorded complaints of discomfort to mankind and yet there appears to be no permanent treatment for this clinical condition. This study was designed to evaluate the clinical efficacy of potassium binoxalate gel and neodymium:yttrium-aluminum-garnet (Nd:YAG) laser on dentin hypersensitivity for a period of 9 months. Eighty teeth (20 subjects, 25-55 years old, M = F) were evaluated in a split-mouth design to receive potassium binoxalate (group A, 40 teeth) and Nd:YAG (group B, 40 teeth: 1 W, 10 Hz, and 60 s, irradiated twice). The diameter of output beam was about 300 µm with a distance of 2 mm between laser fiber or tip and tooth surface. The clinical efficacy was evaluated by air-blast test and cold-water test using visual analog scale. Electron microscopy photomicrographs were taken to confirm the results. Analysis was done at baseline; immediately post-treatment; and at 3, 6, 9 months post-treatment. Student's paired and unpaired T tests were used to evaluate the statistical analysis. Both treatment modalities were effective in reducing dentine hypersensitivity. However, Nd:YAG laser was better when intragroup comparison was made at 9 months post-treatment. Nd:YAG lasers is better in long-term treatment (up to 9 months) owing to the melting of dentinal tubules. However, due to depth of penetration of microcrystals, gel was better when ease of the procedure is considered. Nevertheless, both treatment modalities resulted in recurrence. Hence, further studies are needed to discover an agent, which can be considered as a "gold standard".

Treatment of dentin hypersensitivity with a low-level laser-emitting toothbrush: double-blind randomised clinical trial of efficacy and safety.

Dentin hypersensitivity (DH) is defined as pain derived from exposed dentin in response to chemical, thermal, tactile, or osmotic stimuli that cannot be explained as having arisen from any other dental defect or disease. The aim of this trial was to test the efficacy and the safety of a low-level laser-emitting toothbrush on management of DH. A prospective, double blind, randomised clinical trial was designed; 96 individuals with hypersensitive teeth without caries or fracture were selected as subjects. The subjects were randomly allocated to either the test group with the 635 nm per 6 mW laser-emitting toothbrush, or the control group with the 635 nm per 12.9 µW light-emitting diode (LED) toothbrush. An air blast was applied with a dental air syringe held 3 mm away from the selected tooth and a visual analogue scale (VAS: 0-10) was used to quantify subjective pain. Assessments were completed at a screening visit and after 2-week and 4-week of using a test/control toothbrush. Results demonstrated that the use of both control and test toothbrushes resulted in decreased discomfort after 4 weeks. In the test group, pain intensity scores decreased from 5.8 ± 1.2 to 2.3 ± 1.6, and in the control group, the scores decreased from 6.4 ± 1.3 to 5.5 ± 2.0 (P < 0.05). This decrease was significantly greater in the test group. There were no significant adverse events or side effects. It was concluded that the use of the low-level laser emitting toothbrush is a safe and effective treatment option for the management of DH.