ardavan etemadi

 This study aimed to assess the effect of repeated irradiations of 660 nm photobiomodulation therapy (PBMT) after photodynamic therapy (PDT) with curcumin on the viability of human gingival fibroblasts (HGFs).

 In this in vitro, experimental study, HGFs were cultured and assigned to five groups: One control group with no intervention and four experimental groups of PDT with curcumin, PBMT (660 nm laser irradiation) immediately after PDT, PBMT immediately and 24 hours after PDT and PBMT immediately and 24 hours and 48 hours after PDT. Cell viability was assessed after 1, 4, and 7 days using the methyl thiazolyl tetrazolium (MTT) assay. Data were analyzed by one-way ANOVA.

 On day 1, the control group had no significant difference with one-time (P=1.00), two-time (P=1.00), and three-time (P=0.88) laser irradiation groups. On day 4, the difference between the control and one-time (P<0.001), two-time (P<0.001) and three-time (P=0.02) laser irradiation groups was statistically significant, suggesting more cell viability in test groups. On day 7, the three-time laser irradiation group showed significant cell viability compared to the other two test groups but not with the control group (P=0.98).

 PBMT with 660 nm laser irradiation after PDT with curcumin would increase the viability of HGFs by increasing the frequency of irradiation.

 Photobiomodulation (PBM) is considered a promising adjunctive approach in regenerative medicine. This study aimed to investigate the proliferation and adhesion of human gingival fibroblast (HGF) cells to a collagen membrane following PBM.

 Cultured HGF cells on a collagen membrane received PBM at wavelengths of 808 nm, 915 nm (2 and 4 J/cm2), and 660 nm (2.1 and 4.2 J/cm2) in interventional groups, while non-irradiated cells served as the control. On days 1 and 3 post-irradiation, cell proliferation was measured by MTT assay and adhesion to the membrane was assessed under the scanning electron microscope (SEM).

 Cell proliferation significantly increased in interventional groups compared to the control, with the most significant increase at 915 nm (4 J/cm2) in both time points. On the first day, the 808 nm and 660 nm lasers demonstrated similar results, significantly lower than the 915 nm laser (2 J/cm²). On day 3, the 660 nm, 808 nm, and 915 nm (2 J/cm²) groups showed comparable results. Qualitative analysis by the SEM identified spindle-shaped cells with multiple extended projections in 915 nm groups, especially at an energy density of 4 J/cm2. Groups of 660 nm and 808 nm (4 J/cm2) showed spindle-shaped cell morphology. No distinct cellular morphology indicative of enhanced adhesion was observed at 808 nm (2 J/cm2).

 The most effective PBM setup for promoting HGF proliferation and adhesion to a collagen membrane was identified at 915 nm (4 J/cm2)

 Many surgical procedures in soft tissue are performed using diode lasers. This study aimed to assess the temperature rise and pain following the use of 810 and 980 nm diode lasers for second-stage dental implant surgery.

 This clinical trial was conducted on 24 osseointegrated dental implants that were randomly divided into two groups of 810 nm and 980 nm diode lasers. The temperature rise in each group was measured right after uncovering by the laser and 15 minutes later by a thermocouple, compared with the baseline temperature of gingival tissue. The level of pain was also measured at 24 hours postoperatively by using a visual analog scale. Data were analyzed by ANOVA, Tukey’s test, and t test (alpha=0.05).

 Within-group comparisons by ANOVA showed a significant difference in tissue temperature between the three-time points in both groups (P<0.0001). Pairwise comparisons by Tukey’s test showed that the temperature at baseline (P<0.0001) and 15 seconds after uncovering was significantly lower than that immediately after uncovering in both groups (P<0.0001). The mean tissue temperature and the mean pain score in the 980 nm laser group were significantly higher than the corresponding values in the 810 nm laser group (P<0.05).

 According to the results, temperature rise in the use of the 980 nm laser was higher than the 810 nm laser. The use of 810 nm diode laser was associated with lower temperature rise and significantly lower pain score after 24 hours.

Nowadays, antimicrobial photodynamic therapy (aPDT) has been introduced as one of the minimally invasive methods for disinfection of the surfaces of dental implants. Being derived from seaweed, Chlorella has been used as a photosensitizer in this study. This study aimed to investigate the impacts of aPDT with Chlorella on the rate of reduction of Streptococcus salivarius in vitro.

The minimum inhibitory concentration of Chlorella, the sublethal exposure to 660 nm diode laser irradiation, and the minimum sublethal dose of aPDT utilizing Chlorella against S. salivarius were determined. Finally, the CFU/mL value of each plate was calculated. Then, Tukey HSD and one-way ANOVA tests were utilized for comparison the number of colonies after the interventions.

A concentration of 250 μg/mL of Chlorella at an irradiation time of 3 minutes, was identified as a sublethal dose of aPDT for the reduction of S. salivarius. In contrast, the application of aPDT utilizing a 660 nm diode laser for 4 minutes in combination with Chlorella at a final concentration of 500 μg/mL, demonstrated significantly greater efficacy in reducing S. salivariuscompared to the other experimental groups (P < 0.001).

Chlorella 500 μg/mL mediated aPDT (660 nm, 4 minutes) has a significant effect on reducing S. salivarius count.

 This study aimed to assess the photobiomodulation effects of blue and red lasers on the proliferation and osteogenic differentiation of periodontal ligament mesenchymal stem cells (PDLMSCs).

 PDLMSCs were cultured and tested in 4 groups. The first two groups were exposed to 445 nm diode laser irradiation (200 mW, 6 and 12 J/cm2), and the third group was exposed to
660 nm diode laser irradiation (50 mW, 4 J/cm2). The fourth group was also considered as the
control group without irradiation. Cell viability/proliferation was assessed by MTT assay. RUNX2, alkaline phosphatase (ALP), collagen type 1 (col1), and osteocalcin (OCN) were evaluated by RTPCR, and Alizarin red was used to evaluate the colonization. The data were analyzed by means of one-way analysis of variance.

 The results of our study showed that cell survival/proliferation in the second group was significantly lower than that in the control group on days 1 and 7 (P<0.05). RT-PCR showed a significant increase in osteogenic genes in all three laser groups compared to the control group (P<0.05). All groups showed a significant increase in calcium content compared to the control group (P<0.05). ALP activity also confirmed the osteoblastic differentiation of cells in laser groups.

 445 nm and 660 nm lasers with the studied parameters showed positive effects on the proliferation and osteoblastic differentiation of PDLMSCs.

This study reviewed the literature regarding the correlation of periodontal disease and outcome of in vitro fertilization (IVF).

"IVF", "In Vitro Fertilization", and "Periodontitis" were searched in PubMed, Web of Science, and Google Scholar databases to find English articles published up to August 2022. A free online resource developed by the Canadian Agency for Drugs and Technologies in Health was used to search the grey literature. Duplicate screening and extraction of citations were also carried out. No search filter was applied during searching. Two independent reviewers evaluated the title and abstract of the retrieved articles. Next, the articles retrieved in the initial search were reviewed independently for relevant information to the research question.

The relationship between periodontitis and IVF has been studied in a limited number of studies. According to most articles, periodontal disease may affect IVF implantation and vice versa in women who want to conceive through this procedure. Low sperm motility and reduction in sperm count were also seen in males with periodontitis. Only one study found no correlation between the presence of periodontal disease and unwanted IVF results.  

According to the results, periodontitis can impair the reproductive function since it causes systemic bacteremia. Oral health should be addressed by the primary care providers before the onset of any fertility treatment. There is; however, a need for further investigations into the possible implications of periodontal disease in women seeking fertility care.

Implant surface disinfection is the most difficult phases in treatment of peri-implantitis. This study sought to assess the efficacy of antimicrobial photodynamic therapy (aPDT) with phycocyanin and diode laser for the reduction of Porphyromonas gingivalis.

In this in vitro, experimental study, first the minimum inhibitory concentration (MIC) of phycocyanin, the sub-lethal exposure time of the diode laser, and the sub-lethal dose of aPDT were determined. The wells containing P. gingivalis suspension were randomly divided into three experimental groups for exposure to ½ MIC phycocyanin for 5 minutes, minimum lethal dose of diode laser (635 nm, 4 minutes), and aPDT with phycocyanin and diode laser. The positive control group was exposed to 0.2% chlorhexidine (CHX) for 5 minutes, and the negative control group received no treatment. The colony count was calculated in the five groups and compared using one-way ANOVA and t test.

aPDT with a diode laser (635 nm, 4 minutes) and 125 μg/mL phycocyanin caused a significantly greater reduction in P. gingivalis count (mean reduction of 44.24%) compared with other groups (P < 0.0001). Minimum and maximum colony counts were noted in 0.2% CHX and negative control groups respectively. The reduction in the colony count was significant in all experimental groups, compared with the control group (P < 0.0001).

aPDT with 635-nm diode laser and phycocyanin can significantly decrease P. gingivalis count in vitro. Considering the conservative nature of this modality, it may be used for the decontamination of peri-implant.

Toothpastes and mouthwashes contain chemicals that may be harmful to oral tissues. This study assessed the cytotoxicity and antibacterial activity of toothpastes and compare the Iranian and foreign toothpastes and mouthwashes available in the Iranian market in this respect.

Twenty samples (13 toothpastes and 4 mouthwashes) were selected. The cytotoxicity of 1, 10, and 50 mg/mL of toothpastes and 0.05, 2 and 10 µL of mouthwashes was measured after 1, 15 and 30 min of exposure to human gingival fibroblasts, each in triplicate. The methyl thiazolyl tetrazolium (MTT) assay was used for cytotoxicity testing. The serial dilution method was utilized to determine the minimum inhibitory concentration (MIC) of each sample against Lactobacillus acidophilus (L. acidophilus) and Streptococcus mutans (S. mutans). Two-way ANOVA and Tukey’s test were used for data analysis.

A significant difference in cytotoxicity was noted among different products (P=0.00). The difference in cytotoxicity of each sample was not significant at 1, 15 and 30 min (P=0.08). The obtained MIC for all toothpastes and mouthwashes was between 0.0039 mg/mL and 0.0156 mg/mL, except for Sensodyne toothpaste and Oral B mouthwash.

Some brands of toothpastes have higher cytotoxicity due to their composition, and their cytotoxicity should not be overlooked. The antibacterial activity of the samples was almost equal when they were in contact with L. acidophilus and S. mutans except for the Irsha mouthwash, Sehat, Darugar and Bath toothpastes. The antibacterial effect of toothpastes and mouthwashes increased with an increase in exposure time.

The aim of the present study was to compare shear bond strength (SBS), adhesive remnant index and enamel cracks in bonding and rebonding of brackets to enamel, conditioned with erbium-doped yttrium aluminium garnet (Er:YAG) laser and conventional acid-etching.

Fifty-two bovine lower incisors were randomly divided into four groups consisting of group 1 (acid-conditioning in both bondings), group 2 (acid-conditioning in first and laser-conditioning in second bonding), group 3 (laser-conditioning in first- and acid-conditioning in second bonding), and group 4 (laser-conditioning in both bondings). After bracket placement, the samples were thermocycled and tested for SBS in both bonding procedures. Adhesive remnant index scores and enamel cracks were also determined. Tukey's test and one-way analysis of variance was used for statistical analysis (P<0.05).

Mean SBS in the first bonding was 23.59MPa in groups 1 and 2, and 6.9MPa in groups 3 and 4. (P<0.001). The acid-etched teeth had a significantly lower SBS in rebonding, regardless of the reconditioning method (P<0.001). The SBS of the teeth conditioned with Er:YAG laser in the first bonding did not show significant changes in rebonding, although mean SBS was higher compared to the first bonding (P=0.675). Bonding most often failed at the enamel-adhesive interface and enamel cracks were observed in a few teeth.

The method of primary enamel preparation can affect SBS in rebonding. Based on our results, the mean SBS of Er:YAG-conditioned groups was clinically acceptable in bonding and rebonding, although it was lower compared to the acid-etched samples.

This study aimed to compare the colonization of Enterococcus faecalis (E. faecalis), Escherichia coli (E. coli), Streptococcus mutans (S. mutans) and Staphylococcus aureus (S. aureus) isolated from the oral cavity on different suture materials used in oral implantology.

Patients scheduled for implant surgery were included in this study. After flap approximation, the surgical site was sutured using silk, nylon, polyglactin 910 (Vicryl®) and triclosan-coated polyglactin 910 (Vicryl® Plus) sutures in a randomized order. Seven days after surgery, the sutures were removed and incubated in bile esculin agar (for E. faecalis), MacConkey agar (for E. coli), mitis salivarius agar (for S. mutans), and mannitol salt agar (for S. aureus) at 37°C for 24 h. The colonies were then counted. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests.

Vicryl® sutures showed the highest accumulation of E. faecalis, followed by Vicryl® Plus, nylon, and silk. There was no significant difference between nylon and silk (P=0.5) or between Vicryl® and Vicryl® Plus (P=0.4). Vicryl® Plus sutures showed the highest accumulation of E. coli followed by Vicryl®, silk and nylon (P<0.01). Vicryl® sutures showed the highest accumulation of S. mutans, followed by Vicryl® Plus, silk, and nylon. Vicryl® Plus sutures showed the highest accumulation of S. aureus, followed by Vicryl®, nylon, and silk.

Nylon sutures showed the least microbial accumulation. Vicryl® and triclosan-coated Vicryl® Plus sutures had no advantage over the commonly used silk sutures in decreasing the number of bacteria.

The aim of this article was to evaluate reports in the scientific literature that used antimicrobial photodynamic therapy (aPDT) with a blue light source and curcumin and riboflavin as photosensitizers in the management of periodontitis.

The search was conducted in electronic databases, including PubMed, Web of Science, and Scopus, with the keywords “photodynamic therapy”, “antimicrobial photodynamic therapy”, “laser activated disinfection”, “photoactivated disinfection”, “light activated disinfection” “LED”, “Periodontitis”, “Curcumin”, “Riboflavin”, and “periodontitis” from 2012 to 2020.

After evaluating a total of 24 relevant articles, 13 articles were selected, full texts were read, and the data were extracted and placed in a table.

Reviewing articles showed that curcumin as a photosensitizer activated by a blue wavelength is effective in the elimination of the various bacterial species involved in periodontal disease, and to the best of our knowledge, there is no study that has shown this substance does not reduce bacteria. According to the result of the articles, riboflavin as a photosensitizer activated by blue light can reduce bacteria that are involved in periodontitis, but other studies have reported that blue light alone can also reduce bacteria significantly. Therefore, more in-vitro and clinical trial studies are needed to give a more conclusive opinion on the effectiveness of riboflavin as a photosensitizer in the treatment of periodontitis.

Photobiomodulation therapy (PBM) is emerging as an effective strategy for the management of wound healing. The application of red and near infra-red light sources in laser therapy has been the subject of most researches in recent literature. Considering the lack of sufficient evidence in assessing the blue light in PBM, we aimed to investigate the photobiomodulation effect of a blue diode laser on the proliferation and migration of cultured human gingival fibroblast cells as a preliminary in vitro study.

Human gingival fibroblast cells were irradiated with a blue diode laser at a 445 nm wavelength. Irradiation was done using three different powers of 200 mW (irradiation times of 5, 10,15, and 20 seconds); 300 mW (irradiation times of 5, 10, and 15 seconds); and 400 mW (irradiation times of 5 and 10 seconds). The fibroblast cells without laser exposure were considered as control. After 24 hours of incubation, the MTT assay and the wound scratch test were performed on the cells to investigate the biomodulation effect of the blue laser on the proliferation and migration of the cells respectively. The results were analyzed by one-way ANOVA and a post-hoc Tukey test with a P value <0.05 as a statistical significance level.

PBM with blue diode laser at power densities of 400 mW/cm2 with irradiation times of 10 and 15 seconds corresponding to energy densities of 4 and 6 J/cm2 exerted the statistically significant positive effect on both proliferation and migration of gingival fibroblast cells.

Considering the encouraging findings of this study, PBM with blue diode laser can promote proliferation and migration of human gingival fibroblasts, the key cells involved in the process of oral wound healing.

ntroduction: Providing reliable bonding of the bracket base and the zirconia surface is required to apply orthodontic force. The purpose of this scientific experiment was to evaluate the efficacy of three different methods of surface preparation for Zirconia, including surface roughening, sandblasting and the Nd: YAG laser, in the shear bond strength (SBS) of the orthodontic brackets.

Fifty-four discs of zirconia were divided into three groups of 18: A) Hydrofluoric acid etching, B) sandblasting, and C) Nd: irradiation using the power of 1.5 W for 10 seconds. After bonding the brackets, the samples were slowly thermo-cycled (1000 times) for 24 hours. The SBS test was performed by a universal testing machine at a head speed of 0.5 mm/min. The adhesive remnant index (ARI) was scored at a magnification of 10 in the stereo microscope. All data were collected and analyzed using the variance, Kruskal-Wallis, Tukey, Don, and Weibull tests (α = 0.05).

The HF acid etching group (6.11± 0.94 MPa) had the highest SBS, which was followed by the laser group (6 ± 0.61 MPa) and the sandblast group (3.1080 ± 0.82 MPa). There was a significant statistical difference between the laser and HF groups and the sandblast group (P < 0.05) and no significant difference between the HF group and the laser group (P = 0.03).

Based on the obtained bond strength, the Nd: YAG laser with a power of 1.5 W could be a substitute treatment method for the HF acid-etching.

Previous studies have shown that some dyes used in photodynamic therapy (PDT) have a low pH and may cause root demineralization and remove the smear layer. This study aimed to assess and compare the effects of root biomodification with citric acid and PDT on the adhesion and proliferation of human gingival fibroblasts (HGFs).

In this in vitro experimental study, 75 single-rooted teeth extracted due to periodontal disease were assigned to the following treatment groups: (I) Scaling and root planing (SRP) alone; (II) SRP + citric acid (pH=1, 60 s); (III) PDT with toluidine blue (TB; 635 nm laser,150 mW for 30 s); (IV) PDT with methylene blue (MB; 660 nm laser, 150 mW for 30 s) and (V) PDT with indocyanine green (ICG; 810 nm laser, 150 mW for 30 s). Fibroblasts were then cultured in Dulbecco’s modified Eagle’s medium along with the treated root pieces. Adhesion and proliferation of fibroblasts were quantified using the methyl thiazolyl tetrazolium (MTT) assay at 24, 48 and 72 hours. Data were analyzed using SPSS ver-sion 22 by repeated measures ANOVA. Pairwise comparisons were performed by the LSD test.

Adhesion and proliferation of HGFs significantly increased in all groups from 24 to 72 hours (P=0.0001). There was no significant difference in this respect among the groups at the three time points (P=0.143).

PDT did not have any adverse effect on the adhesion and proliferation of HGFs on dentin, which confirms the safety of this treatment modality.

This study aimed to assess the effect of erbium-doped yttrium aluminum garnet (Er:YAG) and erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers on the shear bond strength (SBS) of ceramic brackets debonding from the surface of composite blocks.

Thirty-six composite blocks were fabricated using Filtek Z250 light-cure composite. The surface of blocks was etched with 37% phosphoric acid for 30 seconds and then rinsed with water for 20 seconds and dried. Maxillary right central incisor ceramic orthodontic brackets were bonded to the surfaces of composite blocks using Transbond XT adhesive and were cured for 40 seconds. Twelve samples were irradiated with Er:YAG laser, while 12 samples were irradiated with Er,Cr:YSGG laser, and the brackets were then debonded using a universal testing machine. Twelve samples served as controls (debonding using the universal testing machine without using a laser). The adhesive  index score and bracket or composite cracks were evaluated under a stereomicroscope. One-way analysis of variance (ANOVA) was used for the comparison of the three groups. Kruskal-Wallis test was used to compare the ARI scores.

The mean SBS was 17.01±5.22 MPa with Er:YAG laser, 18.03±6.46 MPa with Er,Cr:YSGG laser, and 16.61±6.73 MPa in the control group; the difference of the three groups was not significant (P=0.835). The difference in the ARI scores and enamel and composite cracks was not significant either (P>0.05).

This study did not show any reduction in the bond strength of ceramic bracket to composite blocks after Er:YAG and Er,Cr:YSGG laser irradiation.

The mean SBS in the groups was 33.05, 28.69, 24.37, and 31.53 MPa, respectively, with no statistically significant differences (P=0.205). Significant differences in post-irradiation temperature were noted among the lased groups (P=0.000). Debonding mainly occurred at the adhesive-enamel interface in the 1-W laser and control groups and at the bracket-adhesive interface in the 1.5-W and 2-W laser groups. Enamel structure was amorphous and irregular following laser irradiation.

Application of zirconia in dentistry has increased due to its good properties. Since zirconia is not possible to be etched, evaluation of the other methods of surface treatment is important.
The aim of this study was to evaluate zirconia surfaces treated by different output powers of Er: YAG laser and sandblasting technique by scanning electron microscope (SEM).
15 specimens were prepared of 3Y-TZP ceramic material. After polishing of all the samples, divided into 5 groups; control group, 1.5 W Er: YAG laser irradiated group, 2.5W Er: YAG laser irradiated group, 3.5 W Er: YAG laser irradiated and sandblasted group. Then SEM image of each group were prepared and analyzed.
The SEM images of study groups showed there is no significant difference between control group and laser groups at × 3000, but at the more magnifications (× 15000 and × 60000), with increasing laser power, surface roughness and deformation of crystals increases. SEM of Sandblasted group showed a change in surface texture with the formation of microretentive grooves and deformation of zirconia crystals shape.
By increasing the Er: YAG laser power on zirconia ceramics, the surface roughness increases but not impressive. Application of sandblasting technique on zirconia provides greater surface roughness than Er: YAG laser treatment. 1.5 W (150 mJ) Er: YAG laser radiation has no significant effect on surface morphology of zirconia but 2.5 W (250 mJ) and 3.5 W (350 mJ) outputs, change the surface morphology.

Many studies have evaluated re-etched enamel by using scanning electron microscopy (SEM); however, there is no evidence regarding the use of Erbium-doped yttrium aluminium garnet (Er:YAG) laser at primary and secondary bonding instead of acid etching with regards to enamel surface changes. The purpose of the present study was to determine that whether or not the methods of primary and secondary enamel preparation affect enamel characteristics after rebonding, by using SEM analysis.
Twelve freshly extracted premolars were divided into 4 groups. The samples in each group were conditioned by acid etchant or Er:YAG laser at primary conditioning, according to the instructions. Afterwards, they were bonded with orthodontic brackets. After debonding, the samples were prepared for second conditioning. Also, two samples were conditioned only once with acid etchant or laser, to compare enamel morphology changes with those after re-etching. Finally, buccal enamel surfaces were evaluated using SEM.
Enamel etching patterns were observed in the samples which had been acid-conditioned at first or at both conditionings. The samples irradiated by Er:YAG laser showed amorphous and irregular surfaces, with no signs of typical etching patterns. A large deep gap was seen in one of the samples irradiated with laser at primary and secondary conditionings, which might have penetrated the underling layers of enamel and dentin.
Enamel surface preparation with Er:YAG laser produces irregular and indistinct morphologic changes, completely different from those produced after acid etching at both conditioning and reconditioning. Therefore, it is recommended to use this laser with caution to avoid permanent enamel damage.

Application of zirconia ceramics has increased. Since the commonly used surface treatment for porcelain, i.e. acid etching is not efficient for zirconia surfaces, evaluation of other surface treatment methods for zirconia is important. The aim of this study was to compare the shear bond strength (SBS) of metal brackets to zirconia treated with different powers of Er:YAG laser, sandblasting and silane.
In this experimental study, five blocks of 3 mol% yttria stabilized tetragonal zirconia ceramics (3Y-TZP-A) were cut into small cubes. After the sintering process, 72 samples were assigned to six groups (n=12). The first group did not receive any surface treatment. The second, third and fourth groups were irradiated with Er:YAG laser with 1.5 W (150 mJ), 2.5 W (250 mJ) and 3 W (300 mJ) powers, respectively in a long pulse mode for 20 seconds. The samples in the fifth group were sandblasted. The sixth group samples were silanized. After bonding of brackets to the samples, they were stored in distilled water, thermocycled and their SBS was measured by a universal testing machine. Mode of failure was assessed by a stereomicroscope.
The SBS of brackets to zirconia in groups one to six was 0.31±0.23, 0.51±0.14, 1.11 ±0.40, 3.32±1.52, 9.5±2.99 and 3.88±2.20 MPa, respectively. ANOVA revealed a significant difference among the six groups. Tamhane’s test showed that the SBS in group five was significantly higher than that in the other groups. Bond failure occurred at the adhesive/zirconia interface in all groups.
Surface treatment of zirconia with sandblasting provided appropriate bond strength of brackets for clinical applications. But, Er:YAG laser and silane did not create sufficient SBS to zirconia surfaces.

The purpose of this study was to evaluate amalgam surfaces treated by different output powers of erbium-doped yttrium aluminum garnet (Er:YAG) laser by scanning electron microscope (SEM). Twenty-one amalgam blocks (8 mm × 8 mm, 3 mm thickness) were prepared by condensing silver amalgam (into putty impression material. After keeping them for 24 hours in distilled water, they were divided into 7 groups as follow: G1: Er:YAG laser (1 W, 50 mJ), G2: Er:YAG laser (2 W, 100 mJ), G3: Er:YAG laser (3 W, 150 mJ), G4: Sandblast, G5: Sandblast + Er:YAG laser (1 W, 50 mJ), G6: Sandblast +Er:YAG laser (2 W, 100 mJ) and G7: Sandblast +Er:YAG laser (3 W, 150 mJ). Then after preparation of all samples, they were examined by SEM. The SEM results of amalgam surfaces treated by different output powers of Er:YAG laser showed some pitting areas with non-homogenous irregularities It seems that the application of sandblasting accompanied by Er:YAG laser irradiation can provide proper surface for bonding of orthodontic brackets.

The aim of this study was to evaluate the composite surface treated by different powers of Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser in comparison with bur preparation via scanning electron microscope. Fourteen composite resin blocks with 15× 10 × 10 mm dimensions were used in this study. The samples were divided to seven groups as follow: Group 1 (power: 1 W, Energy: 50 mJ); Group 2 (power: 2 W, Energy: 100 mJ); Group 3 (power: 3W, Energy: 150 mJ); Group 4 (power: 4 W, Energy: 200 mJ); Group 5 (power: 5W, Energy: 250 mJ); Group 6 (power: 6 W, Energy: 300 mJ); Group 7: Diamond bur. Then, the samples were prepared for SEM examination. The surface treated by Er:YAG laser showed irregular and micro porous surface. It seems that composite surface treatment by Er:YAG laser can be an alternative method for composite repair if suitable parameters are used.

Recent use of lasers for porcelain surface treatment for adhesion of brackets to restorations has not only showed some promising results, but is also accompanied with less undesirable effects among other advantages. The purpose of this study is the comparative electron microscope evaluation of feldspathic porcelain surfaces under irradiation by Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) with different powers (0.75, 1.5 and 2W) via the acid etching with hydrofluoric acid (HF) technique. The glazed porcelain samples were obtained by duplicating labial surfaces of maxillary central incisor teeth. The specimens were randomly treated by 4 different methods. Group1 was etched with hydrofluoric acid 9.6%. Samples in group 2 to 4 were also irradiated by Nd:YAG laser with different powers: 0.75, 1.5 and 2W. Then the samples were prepared for evaluation by scanning electron microscope (SEM). Etching quality from a porosity point of view was similar for group2 and HF group. Laser with power of 0.75W has little potential to create mechanical porosity. In regard of the results of this study, it is possible to benefit from Nd:YAG laser with appropriate parameters for surface conditioning.

Tooth pain and sensitization are the two main causes of discomfort after periodontal flap surgery. Effects of low level laser therapy for reducing pain have already been established; these kinds of lasers have been used for tooth desensitization as well. This controlled blind study sought to compare tooth pain and sensitization after 660nm laser irradiation in a split mouth and also in a control group after periodontal flap surgery. Forty patients were enrolled in this study. In these entire patients periodontal flap surgery was done in the upper anterior segment. In the test group, by tossing of a coin the left or right side was determined for laser irradiation, so central incisor, lateral incisor and canine were irradiated by swiping motion of 660nm laser (AZOR, Russia) 25mW, 4.5 J, and 3 min every other day starting one day after surgery; and in collateral segment a placebo probe was put to blind the patients. In the control group, dressing was used after surgery. One, 3, 5 and 7 days after surgery for both groups visual analog score (VAS) for tooth pain and sensitization were recorded for both sides in each patient. In the laser group, both sides had lower VAS for pain than the control group (P< 0.05) after the first day. There was no statistical difference in the laser group between laser irradiated, or non-irradiated segment and for sensitization between groups. Pain can be reduced after periodontal surgery by using low level 660nm laser therapy. Lower pain in both sides in the laser group may be the result of the spread of mediators and neurotransmitters secreted after laser irradiation, or may be because of scattered radiation in the collateral part.