Photobiomodulation therapy assisted orthodontic tooth movement: potential implications, challenges, and new perspectives. / ­­æ¿€å ‰å ‰å­ç”Ÿç‰©è°ƒèŠ‚ç–—æ³•è¾ 助正畸牙齿移动：潜在的作用、挑战与新观点.

Over the past decade, dramatic progress has been made in dental research areas involving laser therapy. The photobiomodulatory effect of laser light regulates the behavior of periodontal tissues and promotes damaged tissues to heal faster. Additionally, photobiomodulation therapy (PBMT), a non-invasive treatment, when applied in orthodontics, contributes to alleviating pain and reducing inflammation induced by orthodontic forces, along with improving tissue healing processes. Moreover, PBMT is attracting more attention as a possible approach to prevent the incidence of orthodontically induced inflammatory root resorption (OIIRR) during orthodontic treatment (OT) due to its capacity to modulate inflammatory, apoptotic, and anti-antioxidant responses. However, a systematic review revealed that PBMT has only a moderate grade of evidence-based effectiveness during orthodontic tooth movement (OTM) in relation to OIIRR, casting doubt on its beneficial effects. In PBMT-assisted orthodontics, delivering sufficient energy to the tooth root to achieve optimal stimulation is challenging due to the exponential attenuation of light penetration in periodontal tissues. The penetration of light to the root surface is another crucial unknown factor. Both the penetration depth and distribution of light in periodontal tissues are unknown. Thus, advanced approaches specific to orthodontic application of PBMT need to be established to overcome these limitations. This review explores possibilities for improving the application and effectiveness of PBMT during OTM. The aim was to investigate the current evidence related to the underlying mechanisms of action of PBMT on various periodontal tissues and cells, with a special focus on immunomodulatory effects during OTM.

Comparison of different laser-based photochemical systems for periodontal treatment.

PURPOSE: The main aim in periodontitis treatment is to remove supragingival and subgingival biofilm. Mechanical treatment to eliminate pathogenic bacteria is limited by morphological conditions on the root surface. This study assessed the antibacterial effectiveness of different laser-based photochemical systems, particularly a novel curcumin-based option. METHODS: Ninety-one titanium bars were inoculated with an artificial biofilm of common pathogenic periodontal bacteria and inserted into an artificial periodontal pocket model. The following groups (n = 13) were tested: 1, curcumin solution plus SLB laser irradiation (C + L; 445 nm, 0.6 W, 25% duty cycle, 100 Hz, 10 s); 2, curcumin solution (Cur); 3, dimethyl sulfoxide solution (DMSO); 4, SiroLaser Blue (SLB) - laser irradiation (445 nm, 0.6 W, 25% duty cycle, 100 Hz, 10 s); 5, antimicrobial photodynamic therapy (aPDT); 6, antimicrobial photothermal therapy (aPTT); 7, control. The samples were stored in Eppendorf tubes and analyzed microbiologically using quantitative real-time polymerase chain reaction (PCR). The main parameter for analyzing group differences was the total bacterial load. Statistical analysis was performed with nonparametric methods. RESULTS: Statistically significant reductions in bacterial count were observed in all experimental groups (p < 0.05). The mean percentage reductions were as follows: SLB, 95.03%; aPDT, 83.91%; DMSO, 95.69%; C + L, 97.15%. No statistically significant differences in bacteria reduction were observed for laser alone (SLB), DMSO, or curcumin with or without additional laser irradiation. CONCLUSIONS: The greatest antibacterial efficacy was observed in samples treated with aPTT. Using curcumin as a photosensitizing agent for 445 nm laser irradiation did not result in improved antibacterial effectiveness in comparison with laser alone.

Influence of Photobiomodulation Therapy on Gingivitis Induced by Multi-Bracket Appliances: A Split-Mouth Randomized Controlled Trial.

OBJECTIVE: The objective of this split-mouth trial was to investigate the influence of photobiomodulation therapy (PBMT) on adjuvant treatment of gingivitis induced by multi-bracket appliances, after bracket debonding and professional tooth cleaning. MATERIALS AND METHODS: Thirteen patients (mean age 16.15 years; standard deviation ±2.12 years) who had completed active orthodontic treatment with fixed orthodontic appliances in an orthodontic clinic were included on a randomized basis. At time point T0, after bracket debonding and professional tooth cleaning, the papilla bleeding index (PBI) and bleeding on probing (BOP) were assessed in the upper jaw by the blinded investigator (M.S.), who was not aware at any time of which quadrant received PBMT. The study was based on a patient-blinded split-mouth design. In each patient, PBMT was administered by a practitioner (S.S.) in one upper quadrant (wavelength: 660 nm; Power: 100 mW; Power density: 100 mW/cm2; Energy density per application point = 2 J/cm2; Energy per application point = 2 J; Total dose = 52 J/cm2; Total energy = 52 J; Irradiation time: 26 × 20 sec), while the other upper quadrant received a simulated laser application with the laser system turned off. Randomized equal allocation of the sides was accomplished. The second PBI and BOP assessment followed 4-6 days after laser irradiation (T1) by M.S. RESULTS: No statistical differences were observed between the sides with regard to PBI and BOP values at T0 (p > 0.05). The PBI and BOP values decreased significantly between T0 and T1 on both sides (p < 0.05). At T1, the PBI and BOP values were significantly lower in the laser side in comparison with the control side (p < 0.05). CONCLUSIONS: On the basis of these results and study parameters, adjuvant PBMT is able to accelerate the healing process in patients with gingivitis induced by multi-bracket appliances.

Modulation of Tumor Cell Metabolism by Laser Photochemotherapy with Cisplatin or Zoledronic Acid In Vitro.

BACKGROUND/AIM: Laser photochemotherapy is a new approach in cancer treatment using low-level laser therapy (LLLT) to enhance the effect of chemotherapy. MATERIALS AND METHODS: In order to evaluate the effect of LLLT on tumor cells, HeLa cells were treated with cisplatin or zoledronic acid (ZA) followed by LLLT. Cell viability was evaluated with 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. Oxidative phosphorylation and glycolysis were measured using extracellular flux analysis. Immunocytochemistry of heat-shock protein 70 (HSP70) and western blot analysis were performed. RESULTS: LLLT alone increased viability and was associated with lower oxidative phosphorylation but higher glycolysis rates. Cisplatin and ZA alone lowered cell viability, glycolysis and oxidative phosphorylation. This effect was significantly enhanced in conjunction with LLLT and was accompanied by reduced oxidative phosphorylation and collapse of glycolysis. CONCLUSION: Our observations indicate that LLLT may raise the cytotoxicity of cisplatin and ZA by modulating cellular metabolism, pointing to a possible application in cancer treatment.

Intrapulpal Temperature Increases Caused by 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets During Simulated Pulpal Fluid Circulation.

OBJECTIVE: This study investigated temperature increases in dental pulp resulting from laser-assisted debonding of ceramic brackets using a 445-nm diode laser. MATERIALS AND METHODS: Eighteen ceramic brackets were bonded in standardized manner to 18 caries-free human third molars. Pulpal fluid circulation was simulated by pumping distilled water at 37°C through the pulp chamber. The brackets were irradiated with a 445-nm diode laser. Temperatures were measured using a thermal camera at points P1 (center of the pulp) and P2 (in the hard dental tissue) at the baseline (T0), at the start and end of laser application (T1 and T2), and the maximum during the sequence (Tmax). RESULTS: Significant differences in the temperatures measured at P1 and P2 were observed among T0, T1, T2, and Tmax. Significant increases in temperature were noted at points P1 and P2, between T1 and T2, T1 and Tmax, and T2 and Tmax. The maximum P2 values were significantly higher than at P1. The maximum temperature increase measured in the pulp was 2.23°C, lower than the critical threshold of 5.5°C. CONCLUSIONS: On the basis of the laser settings used, there is no risk to the vitality of dental pulp during laser-assisted debonding of ceramic brackets with a 445-nm diode laser.

Effects of 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets on Shear Bond Strength.

OBJECTIVE: The aim of this study was to measure the effect of irradiation with a novel 445-nm diode laser on the shear bond strength (SBS) of ceramic brackets before debonding. MATERIALS AND METHODS: Thirty ceramic brackets (In-Ovation® C, GAC) were bonded in standard manner to the planed and polished buccal enamel surfaces of 30 caries-free human third molars. Each tooth was randomly allocated to the laser or control group, with 15 samples per group. The brackets in the laser group were irradiated with the diode laser (SIROLaser Blue®; Sirona) on three sides of the bracket bases for 5 sec each (lateral-coronal-lateral, a total of 15 sec) immediately before debonding. SBS values were measured for the laser group and control group. To assess the adhesive remnant index (ARI) and the degree of enamel fractures, micrographs of the enamel surface were taken with 10-fold magnification after debonding. RESULTS: The SBS values were significantly lower statistically in the laser group in comparison with the control group (p < 0.05). The ARI scores were also significantly lower statistically in the laser group in comparison with the control group (p < 0.05). No bracket fractures or enamel fractures occurred in either group after debonding. CONCLUSIONS: Irradiation of ceramic brackets with the novel diode laser before debonding significantly reduces the SBS values. This is of clinical importance, as it means that the risk of damage to the teeth, bracket fractures, and the overall treatment time can be reduced.

The enhancing effect of a laser photochemotherapy with cisplatin or zolendronic acid in primary human osteoblasts and osteosarcoma cells in vitro.

BACKGROUND: Photodynamic therapies (PDT) have become increasingly popular in the adjuvant treatment of different tumour entities. Chemotherapeutic agents, such as cisplatin may be used in combination with low-level laser therapy (LLLT) as laser photochemotherapy. The aim of this study was to investigate the effect of LLLT on cell bioviability of normal and malignant bone cells under chemotherapeutic conditions with either cisplatin or zolendronic acid in vitro. METHODS: Primary human osteoblasts (HOB) and an osteosarcoma cell line (Saos-2) were treated with different concentrations of zolendronic acid or cisplatin and irradiated twice with a diode laser (wavelength 670 nm, 120 s, energy outputs of 100mW/cm2 , continuous wave mode). Cell viability was tested by XTT-assay and via histomorphological analysis. RESULTS: LLLT alone increased bioviability for both cell lines. LLLT lowered HOB viability at the three highest concentrations of cisplatin and zolendronic acid. For Saos-2, LLLT reduced cell viability at every concentration of cisplatin. In cases of incubation with zolendronic acid, similar to osteoblasts, LLLT lowered cell viability at the highest concentration only. CONCLUSIONS: Based on the conditions of this study, laser photochemotherapy may be able to raise the cytotoxicity of cisplatin and zolendronic acid in benign and malignant bone cells. This could be of interest in the development of new therapeutic treatment modalities against neoplastic bone diseases like osteosarcoma.

Er:YAG laser treatment in supportive periodontal therapy.

OBJECTIVE: To assess clinical and microbiological outcomes of an Er:YAG laser in comparison with sonic debridement in the treatment of persistent periodontal pockets in a prospective randomized controlled multicentre study design. MATERIAL AND METHODS: A total of 78 patients in supportive periodontal therapy with two residual pockets were included, 58 were available for the whole follow-up period. Root surfaces were instrumented either with a sonic scaler (Sonicflex(®) 2003 L) or with an Er:YAG laser (KEY Laser(®) 3). Clinical attachment levels (CAL), Probing depths (PD), Plaque control record (PCR) and Bleeding on probing (BOP) were assessed at baseline, 13 and 26 weeks after treatment. In addition, microbiological analysis was performed employing a DNA diagnostic test kit (micro-IDent(®) Plus). RESULTS: Probing depths and CAL were significantly reduced in both groups over time (p < 0.05), without significant differences between the groups (p > 0.05). BOP frequency values decreased significantly within both groups (p < 0.05), with no difference between the laser and the sonic treatment (p > 0.05). PCR frequency values did not change during the observation period (p > 0.05). Microbiological analysis failed to expose any significant difference based on treatment group or period. CONCLUSION: Employing both sonic and laser treatment procedures during supportive periodontal care, similar clinical and microbiological outcomes can be expected.

Subjective intensity of pain during supportive periodontal treatment using a sonic scaler or an Er:YAG laser.

OBJECTIVE: To assess the subjective intensities of pain during supportive periodontal treatment using a sonic scaler or an Er:YAG laser. MATERIAL AND METHODS: Forty patients with two residual periodontal pockets following conventional periodontal therapy were treated using a sonic scaler and an Er:YAG laser in a split-mouth design. A visual analogue scale was used for pain assessment directly after each treatment procedure. Additionally, pain was recorded during the treatment of 11 patients at intervals of 0.5 s using an inter-modal intensity comparison. RESULTS: Pain assessment during treatment showed that laser treatment (median pain score: 0.71 U, maximum: 9.94 U, minimum: 0 U) caused less pain than the sonic device (median pain score: 2.17 U, maximum: 11.26 U, minimum: 0 U) (p<0.05) with no difference in the treatment time (p>0.05). These results could be confirmed by the visual analogue scale: pain scores assessed after laser treatment (median: 1 U, maximum: 7 U, minimum: 0 U) were lower than those after sonic instrumentation (median: 3.5 U, maximum: 7.5 U, minimum: 0 U) (p<0.05). CONCLUSIONS: Using an Er:YAG laser during supportive periodontal treatment, painful sensations can be reduced compared with sonic scaler instrumentation.

Short-term clinical effects of adjunctive antimicrobial photodynamic therapy in periodontal treatment: a randomized clinical trial.

OBJECTIVE: The aim of this study was to assess the effect of adjunctive antimicrobial photodynamic therapy (aPDT) in chronic periodontitis. MATERIAL AND METHODS: Twenty patients with untreated chronic periodontitis were included. All teeth received periodontal treatment comprising scaling and root planing. Using a split-mouth design, two quadrants (test group) were additionally treated with aPDT. Sulcus fluid flow rate (SFFR) and bleeding on probing (BOP) were assessed at baseline, 1 week and 3 months after treatment. Relative attachment level (RAL), probing depths (PDs) and gingival recession (GR) were evaluated at baseline and 3 months after treatment. RESULTS: Baseline median values for PD, GR and RAL were not different in the test group and control group. Values for RAL, PD, SFFR and BOP decreased significantly 3 months after treatment in the control group (median delta RAL: -0.35 mm, inter-quartile range: 0.21 mm), with a higher impact on the sites treated with adjunctive aPDT (median delta RAL: -0.67 mm, inter-quartile range: 0.36 mm, p<0.05). GR increased 3 months after treatment with and without adjunctive aPDT (p<0.05), with no difference between the groups (p>0.05). CONCLUSIONS: In patients with chronic periodontitis, clinical outcomes of conventional subgingival debridement can be improved by adjunctive aPDT.