Laser Analgesia Associated with Restorative Dental Care: A Systematic Review of the Rationale, Techniques, and Energy Dose Considerations

Laser Biostimulation Induces Wound Healing-Promoter β2-Defensin Expression in Human Keratinocytes via Oxidative Stress

The innate immune system is the first line of defense of the body composed of anatomical barriers, such as skin and mucosa, as well as effector cells, antimicrobial peptides, soluble mediators, and cell receptors able to detect and destroy viruses and bacteria and to sense trauma and wounds to initiate repair. The human β-defensins belong to a family of antimicrobial small cationic peptides produced by epithelial cells, and show immunomodulatory and pro-healing activities. Laser biostimulation is a therapy widely used to contrast microbial infection and to accelerate wound healing through biological mechanisms that include the creation of oxidative stress. In this paper, we explored laser biostimulation's ability to modulate the production of two β-defensins, hBD-1 and hBD-2, in human keratinocytes and whether this modulation was, at least in part, oxidative-stress-dependent. Human spontaneously immortalized keratinocytes (HaCaT) were stimulated using laser irradiation at a 980 nm wavelength, setting the power output to 1 W (649.35 mW/cm2) in the continuous mode. Cells were irradiated for 0 (negative control), 5, 10, 25 and 50 s, corresponding to an energy stimulation of 0, 5, 10, 25 and 50 J. Positive control cells were treated with lipopolysaccharide (LPS, 200 ng/mL). After 6 and 24 h of treatment, the cell conditioned medium was collected and analyzed via ELISA assay for the production of hBD-1 and hBD-2. In another set of experiments, HaCaT were pre-incubated for 45 min with antioxidant drugs-vitamin C (Vit. C, 100 µM), sodium azide (NaN3, 1 mM); ω-nitro-L-arginine methyl ester (L-NAME, 10 mM) and sodium pyruvate (NaPyr, 100 µM)-and then biostimulated for 0 or 50 s. After 6 h, the conditioned medium was collected and used for the ELISA analysis. The hBD-1 and hBD-2 production by HaCaT was significantly increased by single laser biostimulation after 6 h in an energy-dependent fashion compared to basal levels, and both reached production levels induced by LPS. After 24 h, only hBD-2 production induced by laser biostimulation was further increased, while the basal and stimulated hBD-1 levels were comparable. Pre-incubation with antioxidative drugs was able to completely abrogate the laser-induced production of both hBD-1 and hBD-2 after 6 h, with the exception of hBD-1 production in samples stimulated after NaN3 pre-incubation. A single laser biostimulation induced the oxidative-stress-dependent production of both hBD-1 and hBD-2 in human keratinocytes. In particular, the pro-healing hBD-2 level was almost three times higher than the baseline level and lasted for 24 h. These findings increase our knowledge about the positive effects of laser biostimulation on wound healing.

Evaluation of the effectiveness of photobiomodulation therapy as an alternative method to local anesthesia injection in pediatric dentistry

Background

The idea of receiving local anesthesia (LA) via an injection is a major source of dental fear and anxiety. In children, dental anxiety is considered the main reason for avoiding dental treatments. Moreover, there are potential complications during/after LA administration. Thus, it is necessary to search for painless, low-risk, and nonpharmacological anesthetic approaches.

Aim

This study was performed to evaluate the effectiveness of photobiomodulation (PBM) therapy as an alternative method to LA injection for conventional restorative treatments in pediatric patients.

Settings and Design

This was a split-mouth randomized clinical study.

Materials and Methods

The study included 15 children between 6 and 12 years old. Each child had 2 similar contralateral caries lesions in the first permanent molars in the same jaw, total (30) teeth. For each child, one tooth was treated under conventional LA injection and the other was treated under PBM-based anesthesia. The Wong-Baker's Faces Pain Scale was used for reporting the pain and discomfort levels at the end of the treatments.

Statistical Analysis

Data statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS) version 20. Mann-Whitney U-test was used to compare between the groups.

Results

The PBM-based anesthesia group recorded a mean pain score of 2.27 ± 1.28. The conventional LA group recorded a mean pain score of 1.73 ± 0.7. The difference between the groups was not statistically significant (P = 0.168).

Conclusions

PBM-based anesthesia may be an optional alternative to LA injection for conventional restorative treatments in children with dental anxiety, needle phobia, or special needs, and it deserves further studies and improvement.

Effectiveness of photobiomodulation in reducing pain and producing dental analgesia: a systematic review

PURPOSE

Photobiomodulation (PBM) is reported in many studies to produce dental analgesia without producing thermal damage to tissues. This systematic review aims to assess in vivo studies to support the statement that PBM can produce dental analgesia.

METHOD

A systematic search strategy was constructed, and PubMed, Scopus, and Embase databases were searched. Subsequently, inclusion and exclusion criteria were applied, reference lists were scanned, and hand searched to identify other suitable studies.

RESULTS

Five studies met the inclusion criteria. Meta-analysis was not undertaken due to the heterogenous nature of the studies and data. Positive analgesia outcome was obtained in four out of five studies, and one study with no significant results was criticized for poor reporting of laser parameters, small sample size (six).

CONCLUSION

In general, all studies were criticized for poor discussion of all covariates that could have modified the results, consequently resulting in poor quality of evidence, moderate risk of bias, and poor internal validity, as well as external validity. The systematic review also discussed the potential implications of all variables to be considered for future trials, including pulsing mode, contact modes, and tooth characteristics.

Comparative Evaluation of the Effects of Diode Laser and Desensitizing Agents on the Treatment of Dentin Hypersensitivity: a Clinical Study

Background:

Dentine hypersensitivity (DH) is a frequent clinical problem that represents a long-term painful discomfort for the patients, and for the dentists, it represents a diagnostic and therapeutic challenge.

Objective:

The aim of the research is to verify the effect of the treatment with diode laser SiroLaser Blue (660nm) of DH alone or in combination with different impregnating agents.

Methods:

Fifty patients were included in this research, separated into five groups. All the patients have been asked to define the level of dentine hypersensitivity using VAS (0-10). The first group was treated with Fluor Protector, the second group after the application of Fluor Protector has undergone irradiation with SiroLaser Blue (660nm), the third group was treated with impregnating agent Vivasens, the fourth group, after the application of impregnating agent Vivasens, has had SiroLaser Blue (660nm) irradiation. The fifth group has just been treated with SiroLaser Blue (660nm). The efficiency of the treatment was checked using VAS for every group immediately after the conducted treatment, after 7 days and 1 month.

Results:

Our results showed that all of the desensitizing agents used in the research alone or in combination with a diode laser (660nm) have shown a reduction of DH. The difference has been proven statistically significant in mean values by groups and examinations. Vivasens and diode laser irradiation have provided the best results in the review of mean values after the first examination and one month after the treatment of DH (p<0,05). In our research, the application of diode laser alone has not proven superior to other treatment methods that have been used in the research.

Conclusion:

Vivasens plus diode laser irradiation has provided the best results even after one month since the treatment of DH.

Highly efficient optical fiber sensor for instantaneous measurement of elevated temperature in dental hard tissues irradiated with an Nd:YaG laser

In this in vitro experiment, the effect of 1.064 µm pulsed laser on both enamel- and dentin-dental tissues has been investigated. A total of fifty-five dental hard tissue samples were exposed to Nd:YAG laser that possesses a pulse width of 9 ns and 850 mJ of total energy. An optical fiber sensor was put behind the samples to measure the temperature instantaneously. A novel, to the best of our knowledge, fiber sensor has been proposed and used to measure the heat generated in dental hard tissues instantaneously after the application of laser irradiation on the tissue surface. This optical sensor exhibits a fast response time of about 1 ms and high sensitivity with about 1.975 nm/°C. The findings of this study in decreasing the probability of pulpal necrosis structure while handling the tooth, whether for ablation, welding, or tooth resurfacing purposes, may establish standards for dentists and laser manufacturers (healthcare professionals) that should be followed.

The Use of Lasers in Dental Materials: A Review

Lasers have been well integrated in clinical dentistry for the last two decades, providing clinical alternatives in the management of both soft and hard tissues with an expanding use in the field of dental materials. One of their main advantages is that they can deliver very low to very high concentrated power at an exact point on any substrate by all possible means. The aim of this review is to thoroughly analyze the use of lasers in the processing of dental materials and to enlighten the new trends in laser technology focused on dental material management. New approaches for the elaboration of dental materials that require high energy levels and delicate processing, such as metals, ceramics, and resins are provided, while time consuming laboratory procedures, such as cutting restorative materials, welding, and sintering are facilitated. In addition, surface characteristics of titanium alloys and high strength ceramics can be altered. Finally, the potential of lasers to increase the adhesion of zirconia ceramics to different substrates has been tested for all laser devices, including a new ultrafast generation of lasers.