Purpose : This study was to investigate the patterns of electromyography (EMG) amplitude responses during maximal, eccentric muscle action with shoulder adduction and diagonal movement, at 6 different positions on the dynamometer.Methods : The participants for this investigation were 9 males and 5 females. Testing consisted of each subject performing eccentric muscle exercise of the dominant shoulder muscle at a velocity of 60°/sec and 180°/sec. Muscle activity values was recorded individually from six different muscles and peak torque values were extracted for each test from torque curves once. EMG data were normalized to the highest root mean square (RMS), and were expressed as a % maximum voluntary isometric contraction (%MVIC).Results : The posterior parts of upper extremity muscle complex generate overall high muscle activity (> 40%MVIC) during all testing for eccentric muscle activity with diagonal shoulder movement. Posterior deltoid (PD), upper trapezius (UT), and middle trapezius (MT) muscles show differences between eccentric muscle action with shoulder adduction and eccentric muscle action with diagonal shoulder movement.Conclusion : The present results show that an improved understanding of muscle activity patterns during different movement may benefit many fields of athletic trainers, coaches, and athletes, in addition to assisting in injury prevention for throwers, and even rehabilitation after injury.

The purpose of this study was to increase knowledge about the landing posture that induces anterior cruciate ligament (ACL) injury. Analysis was done to determine the knee abduction moment during single limb landing using our previously proposed mathematical model. Our model has proven that the criterion of knee abduction occurring is when the acting line of the ground reaction force is directed laterally to the lower leg segment. Based on this, we predicted a medial shift of the knee joint and a lateral leaning of the trunk segment to induce the knee abduction moment. To verify the results of our model prediction, we conducted a motion analysis experiment with a single limb-landing task. Three male and four female subjects participated in the experiment. Subjects were instructed to fall from a 30 cm high box and land on a target which was assigned by PC-controlled laser pointers. Since the landing target was unexpectedly moved during landing, the subjects were perturbed and exhibited various landing postures. The results of the landing experiment showed that trunk leaning laterally towards the landing limb and medially shifted knee alignment induced the knee abduction moment. These results are consistent with the results predicted by our model. In conclusion, appropriate control of both lower limb alignment and trunk motion in the frontal plane in essential for reducing the risk of ACL injury.

PURPOSE : To determine the patterns of electromyographic (EMG) responses and torques of upper extremity muscles in overhead throwers during maximal, eccentric muscle action for shoulder flexion (Flex_Ecc), abduction (Abd_Ecc) and diagonal activities (Dia_Ecc) with full glenohumeral internal rotation, at 60, 120, and 180°/s on the dynamometer.METHODS : Seven asymptomatic subjects (7 men, 4 women) who participate in overhead sports at least three days a week volunteered to participate in this study. Subjects were randomly performed with the test procedure which consisted of at least 5 grade maximal-effort repetitions on the three different testing conditions, at 60, 120, and 180°/s on the dynamometer, while we assessed muscle activation of the anterior deltoid (AD), middle deltoid (MD), posterior deltoid (PD), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and biceps brachii (BB) muscles by surface electromyography. EMG data was expressed as a percentage of maximum voluntary isometric contraction (%MVIC) that was obtained from the highest root mean square (RMS, 50 ms) of each muscle and was normalized and averaged.RESULT : AD muscle elicited lower muscle activity during Dia_Ecc than Flex_Ecc and Abd_Ecc (P＜0.05) while the MD, PD, UT, MT, and LT muscles elicited overall greater muscle activities during Dia_Ecc. MD and MT muscle activities were significantly greater for the faster speed than for the slower speed as 60°/s during Abd_Ecc (P＜0.05). Peak torque generated greater muscle strength for Dia_Ecc than Flex_Ecc and Abd_Ecc, and it was significantly greater for the faster speed than slower speed during Dia_Ecc (P＜0.05).CONCLUSION : Posterior upper extremity muscle activities and peak torque values were found to be dependent on eccentric muscle action for diagonal shoulder activity at the faster speed. This study provided evidence that isokinetic eccentric muscle strength testing of the posterior upper extremity muscle was effective to develop of a proper program for overhead sports athletes require forceful stability during deceleration phase.

The present study is aimed to assess the effect of antimicrobial photodynamic therapy (aPDT) on Streptococcus mutans biofilm through teeth whitening light emitting diode (LED).
Planktonic and dynamic biofilm state cultures of S. mutans were used. Erythrosine 20 μM/L was used as the photosensitizer. Irradiation was performed by exposing cultures to clinic and homecare whitening LEDs for 15 minutes. The viability was measured through Colony Forming Unit counts and confocal laser scanning microscopy.
aPDT using whitening LEDs and erythrosine significantly decreased the CFU count of S. mutans compared to that in the control group. Dynamic biofilm group showed more resistant features to aPDT compared with planktonic state. Clinic and homecare whitening LED device showed similar antimicrobial effect.
The whitening LED, which could irradiate the entire oral arch, showed a significant photodynamic effect on cariogenic S. mutans biofilm. aPDT mediated by erythrosine and LEDs used for teeth whitening exhibited promising antimicrobial activity.

This study is aimed to evaluate and compare the surface roughness and microbial adhesion to alkasite restorative material (Cention N), resin-modified glass ionomer (RMGI), and composite resin. And to examine the correlation between bacterial adhesion and surface roughness by different finishing systems.
Specimens were fabricated in disk shapes and divided into four groups by finishing methods (control, carbide bur, fine grit diamond bur, and white stone bur). Surface roughness was tested by atomic force microscope and surface observation was performed by scanning electron microscope. Colony forming units were measured after incubating Streptococcus mutans biofilm on specimens using CDC biofilm reactor.
Cention N surface roughness was less than 0.2 μm after finishing procedure. Control specimens of resin and Cention N specimens were significantly (p = 0.01) rougher. Pearson correlation coefficient (PCC = 0.13) indicated a weak correlation between surface roughness and S. mutans adhesion to the specimens.
Compared with resin specimens, RMGI and Cention N showed lower microbial adhesion. Surface roughness and bacterial adhesion were not significantly different, regardless of the finishing systems.

The aim of this in-vitro study is to evaluate the effect of potassium iodide (KI) on erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans biofilms. S. mutans ATCC 25175 was cultured to form a biofilm on a hydroxyapatite disk. After diluting erythrosine to 20 μM and KI to 10, 50, and 100 mM, respectively, PDT was performed. The number of surviving bacteria was calculated as colony forming units (CFU)/mL and the statistical significance of the difference between groups was confirmed by Bonferroni post-hoc analysis. Cell viability was visually evaluated using confocal laser scanning microscopy (CLSM). As a result of the experiment, a significant decrease (p < 0.05) in CFU was observed in the experimental groups in which PDT was performed after applying KI regardless of the concentration of KI. In addition, a significant reduction (p < 0.05) in CFU was observed in the experimental group to which 100 mM KI was applied compared to 10 mM KI. The same results were confirmed when observing CLSM. KI significantly improved the efficacy of erythrosine-mediated PDT on S. mutans biofilms at all concentrations. This may compensate for the low sensitivity of PDT to biofilm-state bacteria strains, but it is necessary to establish an optimal clinical protocol through further research.

This study investigated the effects of silver diamine fluoride (SDF) and potassium iodide (KI) treatments on the acid resistance of dentin exposed to secondary caries. Sixteen bovine dentin specimens with artificially induced caries were assigned to the following four groups: untreated negative control, untreated positive control, SDF-treated (SDF), and SDF and KI-treated (SDFKI). Multispecies cariogenic biofilms containing Streptococcus mutans, Lactobacillus casei, and Candida albicans were cultured on the specimens for 28 days, except for the negative control group. Specimens from the negative control group were stored in phosphate-buffered saline for that period. After a cariogenic biofilm challenge, the degree of demineralization was evaluated using micro-computed tomography (micro-CT). As a result of data analysis using micro-CT, the demineralization depths of the negative control, positive control, SDF, and SDFKI groups were 149.0 ± 7 μm, 392.0 ± 11 μm, 206.0 ± 20 μm, and 230.0 ± 31 μm, respectively. The degree of demineralization was significantly reduced in the SDF and SDFKI groups compared with that in the untreated positive control group. There were no significant differences between the SDF and SDFKI groups. This study confirmed that SDF and SDFKI treatments increase the acid resistance of dentin to secondary caries. KI did not significantly affect the cariesarresting effect of the SDF.

The aim of this study was to evaluate the antimicrobial effect of photodynamic therapy (PDT) using plaque disclosing agent, 10 - 20 mM erythrosine, as a photosensitizer.
Multispecies cariogenic biofilms containing Streptococcus mutans , Lactobacillus casei and Candida albicans were formed on hydroxyapatite disc. 20 μM, 10 mM and 20 mM erythrosine were applied as a photosensitizer for 3 minutes, and then light-emitting diode (LED) irradiated for 24 seconds. Colony-forming unit (CFU) were measured and biofilms were observed using confocal laser scanning microscopy (CLSM). CFU were significantly decreased in the PDT groups using 10 - 20 mM erythrosine (10 mM, 20mM) and the results were also confirmed by CLSM.
This study confirms the high antimicrobial effect of photodynamic therapy using plaque disclosing agent as a photosensitizer.

The purpose of this study was to evaluate the effect of Indocyanine Green (ICG) and near-infrared (NIR) diode laser on Streptococcus mutans biofilms depending on ICG concentrations.
S. mutans biofilms were formed on a Hydroxyapatite disk, and 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 mg/mL ICG solutions dissolved in sterile distilled water and a NIR diode laser having a power of 300 mW and a wavelength of 808 nm were applied to the biofilms. The temperature changes of the biofilm surface according to the concentrations of the ICG solution were measured using a 1-channel thermocouple thermometer.
Compared to the control group, in the groups with only the 3.0, 4.0, 5.0 mg/mL ICG solution application, and in the groups with the 1.0, 2.0, 3.0, 4.0, 5.0 mg/mL ICG solution application and light irradiation, a statistically significant decrease in the bacterial counts were observed.
The temperature increase according to the concentration of the ICG solutions was 9.53℃, 10.43℃, 11.40℃, 12.10℃, 12.67℃, and 13.63℃ in ICG solutions of 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 mg/mL respectively.This study presents the potential for clinical application of ICG and NIR diode lasers as a new method for preventing dental caries.

The purpose of this study is to investigate the antibacterial effects of indocyanine green (ICG) and near-infrared diode lasers on multispecies biofilms.
Multispecies biofilms of Streptococcus mutans, Lactobacillus casei and Candida albicans were treated with different irradiation time using photosensitizer ICG and 808 nm near-infrared diode laser. Colony forming unit (CFU) was measured, and qualitative evaluation of biofilm was performed with confocal laser scanning microscopy (CLSM). Temperature measurement was conducted to evaluate photothermal effect.
In the groups using ICG and diode laser, reduction in CFU was statistically significant, but the difference in antibacterial effect on L. casei and C. albicans with irradiation time was not significant, and similar results were confirmed with CLSM. Groups with ICG and diode laser showed higher temperature elevation than groups without ICG, and results of measured temperature were similar to the range of hyperthermia.
In conclusion, ICG and near-infrared diode laser showed antibacterial effects on multispecies biofilms, but studies on protocol are necessary for clinical application.