Effect of photobiomodulation on pain level during local anesthesia injection: a randomized clinical trial.

The aim of this study was to investigate the effect of photobiomodulation therapy (PBMT) as pre-treatment on pain level during injection in the anterior maxillary region. 56 Patients were randomly divided into 3 groups, Group 1:980 nm diode laser (n = 22) (experimental), Group 2:980 nm diode laser probe placed in vestibule without radiation (placebo) (n = 22), Group3: no pre-treatment before injection (n = 12) (control). Pain level during injection was evaluated by visual analog scale (VAS). The severity of pain in Group 1(experimental) and Group 2 (placebo) was significantly lower than Group 3 (control). Group 1 had a lesser pain level than Group 2, but the difference in pain level between them was not significant. PBMT with 980 nm wavelength decreased pain level during local anesthesia injection without superiority over placebo.

Can 3D imaging and digital software increase the ability to predict dental arch form after orthodontic treatment?

INTRODUCTION: This study aimed to evaluate the ability of dental clinicians to predict posttreatment dental arch forms in patients with malocclusion with the aid of 3D imaging and digital software in comparison with a conventional method. METHODS: Pretreatment and posttreatment dental plaster casts of 100 patients (200 maxillary models and 200 mandibular models) were selected. Three orthodontists selected the best-fitted archwires among 5 commercially available preformed nickel-titanium archwires using 2 methods. In the conventional method, they fit the archwires to pretreatment casts, and in the digital method, they fit the scanned wire to a 3D digital model, using Ortho-Aid, a locally developed 3D software, using clinical bracket points as reference for wire fitness. The predicted posttreatment archwire in each method was compared with the best-fit archwire on the actual posttreatment model of each patient in both methods, and the level of agreement was calculated. The interobserver agreement between the 3 orthodontists in each method was evaluated using intraclass correlation coefficient and the Dahlberg formula. RESULTS: Orthodontists predicted the final treatment outcome in 50% of cases using the conventional method and 58% using the digital method. However, the range of method error was significantly higher in the conventional method (0.425-3.853 mm for the conventional vs 0.451-0.584 mm for the digital). CONCLUSIONS: Although the clinicians' ability to predict the final dental arch form after orthodontic treatment and the agreement between clinicians increased by the use of digital equipment, orthodontists can predict the final arch form in about 60% of patients.

The Combined Effects of Levothyroxine and Low Level Laser Therapy on Wound Healing in Hypothyroidism Male Rat Model.

Introduction: Hypothyroidism is caused by inadequate production and storage of thyroid hormones. Hypothyroidism is associated with delayed wound healing. Laser therapy may stimulate wound regeneration. The aim of this study was to determine the combined effects of levothyroxine and low level laser therapy during the wound healing process on skin of hypothyroidism male rat model. Methods: Thirty male Wistar rats were randomly divided into 5 groups: control group, hypothyroidism group, hypothyroidism group treated by laser, hypothyroidism group treated by levothyroxine, and hypothyroidism group treated by laser and levothyroxine. To induce hypothyroidism, methimazole was given at a dose of 4 mg/100 mL in their drinking water. After hypothyroidism was proven through immunoassay commercial kit, rats were generally anesthetized with ketamine and xylazine, then, an incisional skin wound was created in a length of 1.2 cm on the back of the ribcage. The surgical day is considered as the zero day. The third and fifth groups were treated with a pulse laser, 810 nm wavelength 80 Hz frequency and 0.2 J/cm2 energy densities for 200 seconds. Levothyroxine was injected to the fourth and fifth groups intraperitoneally. On the 14th day, a normal sample of each healing skin wound was harvested for biomechanical examination. The obtained data were analyzed by the SPSS software 21 and reported as a mean ± standard error of mean (SEM). P < 0.05 was considered statistically significant. Results: The results showed that the mean maximum force and the accomplished work (energy) made a significant difference in the group receiving both laser and levothyroxine synchronously rather than the other groups (P ≤ 0.05). The elasticity of the wound healing in the groups that received laser and levothyroxine synchronously was significantly higher in comparison with the control and hypothyroidism groups but the difference was not significant in comparison with the laser or levothyroxine groups. Conclusion: The results of our study showed that the application of laser and levothyroxine synchronously improves the biomechanical parameters of wound during healing in comparison to the use of laser and levothyroxine solely.

Effect of Pentoxifylline Administration on an Experimental Rat Model of Femur Fracture Healing With Intramedullary Fixation.

BACKGROUND: Globally, musculoskeletal injuries comprise a major public health problem that contributes to a large burden of disability and suffering. Pentoxifylline (PTX) has been originally used as a hemorheologic drug to treat intermittent claudication. Previous test tube and in vivo studies reported the beneficial effects of PTX on bony tissue. OBJECTIVES: This study aims to evaluate the effects of different dosages of PTX on biomechanical properties that occur during the late phase of the fracture healing process following a complete femoral osteotomy in a rat model. We applied intramedullary pin fixation as the treatment of choice. MATERIALS AND METHODS: This experimental study was conducted at the Shahid Beheshti University of Medical Sciences, Tehran, Iran. We used the simple random technique to divide 35 female rats into five groups. Group 1 received intraperitoneal (i.p.) PTX (50 mg/kg, once daily) injections, starting 15 days before surgery, and group 2, group 3, and group 4 received 50 mg/kg, 100 mg/kg, and 200 mg/kg i.p. PTX injections, respectively, once daily after surgery. All animals across groups received treatment for six weeks (until sacrificed). Complete surgical transverse osteotomy was performed in the right femur of all rats. At six weeks after surgery, the femurs were subjected to a three-point bending test. RESULTS: Daily administration of 50 mg/kg PTX (groups 1 and 2) decreased the high stress load in repairing osteotomized femurs when compared with the control group. The highest dose of PTX (200 mg/kg) significantly increased the high stress load when compared with the control group (P = 0.030), group 1 (P = 0.023), group 2 (P = 0.008), and group 3 (P = 0.010), per the LSD findings. CONCLUSIONS: Treatment with 200 mg/kg PTX accelerated fracture healing when compared with the control group.