Comparison of Anti-Microbial Effects of Low-Level Laser Irradiation and Microwave Diathermy on Gram-Positive and Gram-Negative Bacteria in an In Vitro Model

Abstract

Background and Objectives: The aim of this study was to compare the effects of low-level laser therapy and continuous microwave diathermy on the growth of Gram-negative and Gram-positive bacteria and to establish their efficacy as an alternative therapeutic modality. Materials and methods: Laser fluence of 13 Joules (J)/cm2, 18 J/cm2 and 30 J/cm2 were used against several bacterial strains. Microwave dosages of 25, 50 and 100 watts (W) were used, respectively. Results: A significant difference between the three groups was observed using repeated analysis of variance (RANOVA) (F value: 0.74, and p value: 0.001). The Greenhouse–Geisser correction (GG) revealed significant results for laser irradiation alone. However, effect size calculation showed effects with microwave diathermy as well as laser fluence. Conclusions: Low-level laser therapy appears to be an effective modality of treatment when compared with continuous microwave diathermy on the Gram-negative and the Gram-positive bacterial strains tested. Microwave diathermy revealed large and medium effects on the bacterial cell counts with dominant effects on Gram-negative strains.

Efficacy of single versus multiple exposure by electromagnetic modalities on gram-negative and positive bacterial strains in an in-vitro model

“…The experiment was conducted by means of a LLLT, category 4 Laser M 1000 plus (Level-Laser Co., Moglano Veneto-Milano, Italy). The equipment is usually furnished with an inflatable bottom foot switch, which is used to schedule the laser beam as per the requirement ( Dixit et al, 2019 ). The LLLT parameters which were taken into account were as follows: The LLLT equipment was a company made standard semiconductor gallium –aluminium-arsenide (Ga-Al-As), producing a determined power of 1-Watt, constant wave (CW) at a wavelength of 810 nm and a frequency of 500 Hz.…”

“…LLLT which is commonly known as Low Level Laser therapy is as a potent modality of treatment for controlling the growth of Gram positive and Gram negative bacteria ( Barboza et al, 2015 , Dixit et al, 2019 , Nussbaum et al, 2002 ). As they are low-cost devices and are progressively being used in health care system.…”

“…In particular there are researches which states that laser probes with 810 nm wavelength ( Dixit et al, 2019 , Yuan et al, 2018 ) usually have less or no effect on Staphylococcus aureus or Gram-positive strains. Some researchers also emphasizes on contrary findings that LLLT is more effective on Gram positive strains than on Gram negative strains ( Yuan et al, 2018 ).…”

“…In addition to lasers, Microwave diathermy (MWD) is also a physical therapy modality which operates in electromagnetic spectrum ( Dixit et al, 2019 ). MWD uses electromagnetic radio waves with frequencies of 915 and 2456 MHz.…”

“…Microwaves are selectively absorbed in tissues and this property is perfectly suited to treat pathologic procedures that take place in the muscles and adjacent fat ( Effects TP ). However, there is dearth in literature regarding the role MWD and its effects on Gram positive and Gram negative strains which needs to be further discovered ( Dixit et al, 2019 , Kumaran and Watson, 2015 ).…”