Modulatory effects by neodymium-doped yttrium aluminum garnet laser on fibroblast attachment to single rooted tooth surfaces following ultrasonic scaling and root planning: An in vitro study

Effect of photobiomodulation therapy with 660 and 980 nm diode lasers on differentiation of periodontal ligament mesenchymal stem cells

This study aimed to compare the effects of photobiomodulation therapy (PBMT) with 660 and 980 nm diode lasers on differentiation of periodontal ligament mesenchymal stem cells (PDLMSCs). In this in vitro, experimental study, PDLMSCs were obtained from the Iranian Genetic Bank and cultured in osteogenic medium. They were then subjected to irradiation of 660 and 980 nm diode lasers, and their viability was assessed after one, two, and three irradiation cycles using the methyl thiazolyl tetrazolium (MTT) assay. The cells also underwent DAPI staining, cell apoptosis assay by using the Annexin V/PI, Alizarin Red staining, and real-time polymerase chain reaction (PCR) for assessment of the expression of osteogenic genes. Data were analyzed by two-way ANOVA. The two laser groups had no significant difference in cell apoptosis according to the results of DAPI staining. Both laser groups showed higher cell viability in the MTT assay at 4 and 6 days compared with the control group. Annexin V/PI results showed higher cell viability in both laser groups at 4 days compared with the control group. Rate of early and late apoptosis was lower in both laser groups than the control group at 4 days. Necrosis had a lower frequency in 980 nm laser group than the control group on day 6. Alizarin Red staining showed higher cell differentiation in both laser groups after 3 irradiation cycles than the control group. The highest expression of osteopontin (OPN), osteocalcin (OCN), and Runt-related transcription factor 2 (RUNX2) was noted in 660 nm laser group with 3 irradiation cycles at 14 days, compared with the control group. PBMT with 660 and 980 nm diode lasers decreased apoptosis and significantly increased PDLMSC differentiation after 3 irradiation cycles.

In Vitro Effect of Photodynamic Therapy With Curcumin in Combination With Photobiomodulation Therapy by 660 nm on the Viability of Human Gingival Fibroblasts

Introduction: 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). Methods: 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. Results: 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). Conclusion: PBMT with 660 nm laser irradiation after PDT with curcumin would increase the viability of HGFs by increasing the frequency of irradiation.

The effectiveness of scaling and root planing with combined application of air polishing and Nd:YAG laser in periodontal pockets of stage III grade C periodontitis patients: a single-blinded randomized clinical trial

OBJECTIVES

Evaluating the efficiency of combined air polishing and Nd:YAG laser application in addition to scaling and root planning (SRP) in treatment of periodontal pockets of stage III grade C periodontitis patients was the aim of this clinical trial.

MATERIALS AND METHODS

Twenty-four systemically healthy, stage III grade C periodontitis patients were recruited for this clinical trial. In this split-mouth study, the quadrants were randomly allocated to either SRP with combined air polishing (erythritol/chlorhexidine powder) and Nd:YAG laser (2 W, 200 mJ/pulse, 10 Hz) therapy (test group) or SRP alone (control group). A masked examiner recorded clinical parameters such as plaque index (PI), gingival index (GI), bleeding on probing (%) (BOP %), probing depth (PD), and clinical attachment level (CAL) on periodontal charts at baseline, 1 month and 3 months after treatment.

RESULTS

The clinical parameters had significantly reduced 1 and 3 months after treatment compared to baseline for both study groups (p < 0.05). Considering PI, GI, and BOP (%) parameters, there were no significant differences between the study groups at any time points (p > 0.05). While PD and CAL reductions were similar in study groups for moderately deep pockets (5 to 6 mm) (p > 0.05), PD and CAL reductions were significantly greater in test group compared to control group for deep pockets (PD ≥ 7 mm) (p < 0.05).

CONCLUSIONS

The present clinical trial demonstrated that SRP with combined application of air polishing and Nd:YAG laser may be advantageous in sites where mechanical debridement alone cannot access, such as deep pockets in the short term. Long-term, well-designed future studies including clinical, biochemical, and microbiological analyses are needed to determine the effectiveness of this procedure.

CLINICAL RELEVANCE

SRP with combined application of air polishing and Nd:YAG laser provided more reductions in probing depth and clinical attachment level parameters in deep pockets compared to SRP alone.

Effects of Photobiomodulation Therapy with Various Laser Wavelengths on Proliferation of Human Periodontal Ligament Mesenchymal Stem Cells

Several methods have been proposed to enhance the regeneration and healing time in periodontal therapy. Photobiomodulation therapy (PBMT) is a recently suggested novel technique for this purpose. This study aimed to compare the efficacy of PBMT with various laser wavelengths and energy densities on proliferation of human periodontal ligament mesenchymal stem cells (PDLMSCs). The wells containing PDLMSCs were subjected to laser irradiation at 635, 660, 808, and 980 nm wavelengths with 1, 1.5, 2.5 and 4 J/cm² energy densities. Cell proliferation and viability were evaluated after 1, 3, and 5 days with the methyl thiazolyl tetrazolium (MTT) assay and 4,6-diamidino-2-phenylindole (DAPI) staining. No significant difference was observed among the experimental and the control groups on day 1 (P>0.05). On day 3, 808 nm laser at 4 J/cm² energy density and 980 nm laser at all densities had significant differences with control group. On day 5, the control group had significant differences in cell proliferation with 808 nm laser at 2.5 and 4 J/cm² energy densities, and 980 nm laser at all densities. PBMT with 635, 660, 808, and 980 nm wavelengths increased the proliferation of PDLMSCs but the maximum cell viability was prominent after irradiation by 980 nm laser with energy density of 4 J/cm² on day 3.

Comparative analysis of cytocompatible properties of the root surface exposed to diode laser (970 nm) as adjunct to scaling and root planing: An in vitro study

Aims

The aim of the current study was to examine the effects of diode laser (970 nm) when used as adjunct to mechanical debridement on reattachment of fibroblast cell cultures to the root surface.

Materials and Methods

Eighteen extracted single-rooted human teeth were used in the study. Briefly, the anatomical crowns were removed; roots were sectioned and preserved in antiseptic solution. The sections were divided into three groups: (i) scaling and root planing (SRP), (ii) SRP followed by diode laser exposure and (iii) untreated control group. All the sections were inoculated with NIH 3T3 mouse fibroblast cell lines and cell attachment was confirmed by scanning electron microscopy analysis and growth was quantitatively assessed by MTT assay after days 1, 3 and 5.

Results

On intragroup analysis, there was significant cell proliferation seen on day 1 and day 5. However, no significant differences were observed between the treatment groups at the various time points.

Conclusion

970-nm diode laser exposure had a positive effect in enhancing the fibroblast reattachment to root surfaces. However, to ascertain the role of laser treatment in enhancing the rapid cell growth compared to SRP, further quantitative studies with more sample numbers are required.

In Vitro Effect of Photodynamic Therapy with Indocyanine Green Followed by 660 nm Photobiomodulation Therapy on Fibroblast Viability

This in␣vitro study sought to assess the effect of repetitive PBMT on the viability of fibroblasts following aPDT with indocyanine green (ICG). In this in␣vitro experimental study, human gingival fibroblasts (HGFs) were obtained and incubated in a culture medium. After reaching 10 000 cells cm^-2 , the cells were divided into five groups of control, aPDT with ICG and 808 nm (energy density of 24 J cm^-2 ), PBMT immediately after aPDT, PBMT with 660 nm (energy density of 7.2 J cm^-2 ) immediately and 24 h after aPDT and PBMT immediately and 24 and 48 h after aPDT in 48-well plates. Cell viability was evaluated using the methyl thiazolyl tetrazolium (MTT) assay after 1, 4 and 7 days of incubation. Statistical analyses were performed using one-way ANOVA. Cell viability significantly decreased in group 2 (P < 0.002). We observed no significant increase in cell viability at any time point in group 3 (P > 0.05). Cell viability significantly increased in groups 4 and 5 after the first day of incubation (P < 0.000). Emission of 660 nm as PBMT for two and three times along with passage of time would increase the viability of HGFs following aPDT with ICG.

Laser reduction of specific microorganisms in the periodontal pocket using Er:YAG and Nd:YAG lasers: a randomized controlled clinical study

The objective of this study was to evaluate the microbiological and clinical outcomes following nonsurgical treatment by either scaling and root planing, combination of Nd:YAG and Er:YAG lasers, or by Er:YAG laser treatment alone. The study involved 60 patients with generalized chronic periodontitis, randomly assigned into one of three treatment groups of 20 patients. The first group received scaling and root planing by hand instruments (SRP group), the second group received Er:YAG laser treatment alone (Er group), and the third group received combined treatment with Nd:YAG and Er:YAG lasers (NdErNd group). Microbiological samples, taken from the periodontal pockets at baseline and 6 months after treatments, were assessed with PET Plus tests. The combined NdErNd laser (93.0%), followed closely by Er:YAG laser (84.9%), treatment resulted in the highest reduction of all bacteria count after 6 months, whereas SRP (46.2%) failed to reduce Treponema denticola, Peptostreptococcus micros, and Capnocytophaga gingivalis. Full-mouth plaque and bleeding on probing scores dropped after 6 months and were the lowest in both laser groups. The combination of NdErNd resulted in higher probing pocket depth reduction and gain of clinical attachment level (1.99 ± 0.23 mm) compared to SRP (0.86 ± 0.13 mm) or Er:YAG laser alone (0.93 ± 0.20 mm) in 4-6 mm-deep pockets. Within their limits, the present results provide support for the combination of Nd:YAG and Er:YAG lasers to additionally improve the microbiological and clinical outcomes of nonsurgical periodontal therapy in patients with moderate to severe chronic periodontitis.

Stimulation of human gingival fibroblasts viability and growth by roots treated with high intensity lasers, photodynamic therapy and citric acid

OBJECTIVE

The aim of this study was to compare the effect of root biomodification by lasers, citric acid and antimicrobial photodynamic therapy (aPDT) on viability and proliferation of human gingival fibroblasts (FGH).

DESIGN

Groups were divided in control (CC - only cells), and root fragments treated by: scaling and root planing (positice control - SC), Er:YAG (ER-60mJ,10pps,10Hz,10s,2940nm), Nd:YAG (ND-0.5W,15Hz,10s,1640nm), antimicrobial photodynamic therapy (PDT-InGaAIP,30mW,45J/cm²,30s,660nm,toluidine blue O), citric acid plus tetracycline (CA). Fibroblasts (6th passage, 2×10³) were cultivated in a 24-h conditioned medium by the treated root fragments. Cell viability was measured by MTT test at 24, 48, 72 and 96h. In a second experiment, FGH cells (10⁴) were cultivated on root fragments which received the same treatments. After 24, 48, 72h the number of cells was counted in SEM pictures. In addition, chemical elements were analyzed by energy dispersive spectroscopy (EDS). Data was analyzed by two-way ANOVA (first experiment), repeated measures ANOVA (second experiment) and ANOVA (EDS experiment) tests complemented by Tukey's test (p<0.05).

RESULTS

ND, PDT and CA promoted higher cell viability (p<0.05). ND and ER groups presented higher number of cells on root surfaces (p<0.05). ER group presented higher calcium and CA group a higher carbon percentages (p<0.05).

CONCLUSIONS

All treatments but scaling and root planing stimulated fibroblast viability while Er:YAG and Nd:YAG treated root surfaces presented higher number of cells.