The Clinical Evaluation of the Effects of Low-Level Laser Therapy on the Donor and Recipient Sites of the Free Gingival Graft: A Case Series

Introduction: Free gingival grafting is among the most foreseeing procedures for increasing the zone of keratinized attached gingiva and enhancing soft tissue around the teeth and dental implants. Nowadays low-level laser therapy (LLLT) is a promising approach in providing patients with more pleasing results in terms of esthetics and comfort. This study aims to investigate the effects of LLLT on gingival recessions treated with free gingival graft (FGG).Methods: This case series was conducted on 12 individuals requiring a bilateral gingival graft in the mandibular region. There was a 30-day interval between the two operations. The test side was selected randomly and irradiated by a low-level laser (LLL) just before surgery. The patients did not know which side was irradiated. LLLT was applied to the donors’ as well as recipients’ site immediately after the operation and 48 hours later. The patients were instructed to record their post-operative pain in a visual analogue scale (VAS) 3 and 24 hours and 7 days after the surgical procedure. The clinical photographs were taken immediately and 30 days after surgical treatment were graded by three experienced periodontists for color matching to adjacent tissues.Results: Ten individuals could finish the study. The test group presented significantly better shade matching and wound healing at the palatal donor site on days 7, 14 and 21. There was a significant reduction in postoperative pain after 24 hours (P = 0.007). No statistically significant difference was found between both groups in terms of clinical periodontal indices.Conclusion: LLLT could reduce post-operative pain 24 hours after surgical treatment. Furthermore, the application of LLLT could improve the donors’ site healing and the recipients’ site color matching

Major and minor criteria for gastric dystemperaments in Persian Medicine: Sari gastric dystemperament criteria-I (SGDC-I)

<div class="msocomtxt" id="com1" language="JavaScript" onmouseout="msoCommentHide('com1')" onmouseover="msoCommentShow('anchor1','com1')">Background: Gastric disorders are one of the most common human ailments, which impose a huge economic burden on countries. In Persian Medicine (PM), it is possible to predict the susceptibility to gastric diseases with diagnosis of gastric Mizajes (temperaments) and dystemperaments. The semiology of gastric dystemperaments has been investigated in PM textbooks, although the value of each sign and symptom is not mentioned. Consequently, this research is designed to determine the major and minor criteria for classifying gastric dystemperaments on the basis of valid manuscripts and with the help of PM specialists in the present era. Methods: This was a consensus-based study consisting of four phases. In the first phase, reference PM textbooks were studied. Symptoms and signs of gastric dystemperaments were collected and listed in four groups. In the second phase, semi-structured interviews with a sample of PM experts were carried out. Phase three included a focused group discussion with experts. Eventually, findings were integrated from the three study phases in a two-day meeting in Sari City. Results: Selected criteria included eight major and eight minor criteria for hot-cold dystemperament, as well as six major and eight minor criteria for wet-dry gastric dystemperament. Conclusion: Modern lifestyles and the interfering factors are responsible for some changes in diagnostic signs and symptoms according to PM. This was the first step to coordinate PM diagnostic criteria for gastric dystemperaments. Further studies are recommended to reach a unique protocol in the field of PM diagnostics. The next step includes design and validation of national diagnostic tools. &#160

Investigation of the oscillatory behavior of electrostatically-actuated microbeams

ABSTRACT Vibrations of electrostatically-actuated microbeams are investigated. Effects of electrostatic actuation, axial stress and midplane stretching are considered in the model. Galerkin's decomposition method is utilized to convert the governing nonlinear partial differential equation to a nonlinear ordinary differential equation. Homotopy perturbation method (i.e. a special and simpler case of homotopy analysis method) is utilized to find analytic expressions for natural frequencies of predeformed microbeam. Effects of increasing the voltage, midplane stretching, axial force and higher modes contribution on natural frequency are also studied. The anayltical results are in good agreement with the numerical results in the literature

Root Surface Roughness after Treatment with Manual Curette and Er:YAG and Er,Cr:YSGG Lasers

Introduction: This study compared the root surface roughness following scaling and root planning with manual curettes and different powers of Er:YAG and Er,Cr:YSGG lasers using surface profilometry and scanning electron microscopy (SEM). Materials and Methods: In this in vitro experimental study, 50 extracted teeth were buccolingually sectioned into two halves. The obtained contaminated surfaces randomly received the following treatments: SRP with manual curettes (group I), Er:YAG laser irradiation (4 W) (group II), manual curette+Er: YAG laser (1W) (group III), manual curette+ Er,Cr:YSGG laser (150 mJ) (group IV) and Er,Cr:YSGG laser (250 mJ) (group V). Surface roughness (Ra), surface changes (Rz) and maximum roughness changes (Rmax) were calculated before and after treatment while the surface morphology was examined by SEM analysis. The differences in roughness parameters were statistically analyzed using Wilcoxon signed rank test for each modality.Results: Except for the manual curette group (I) in which the roughness parameters decreased significantly (P<0.04 for all), Ra, Rz and Rmax increased in the remaining groups. The reported increases in group II (4W Er:YAG)(P<0.005, P<0.007 and P<0.03, respectively) and group V (250 mJ Er,Cr:YSGG) were statistically significant (P<0.01, P<0.05 and P<0.05). Conclusion: Within the limitations of this study, irradiation of Er:YAG and Er,Cr:YSGG lasers at both powers with and without using manual curettes increased surface roughness values compared to using manual curettes alone. Greater roughness values were obtained by increasing the power of lasers

The Effect of Redistributive Policies on Saving and Capital Accumulation: An Overlapping Generations Approach

Justice is known as one of the most important principles of any economic system and pursuing other objectives such as efficiency and economic growth should go along with achieving justice. In Islamic economics, redistributive justice as a kind of justice can be achieved through obligatory and voluntary charities or through government subsidies. In this study, we generalize two-period overlapping generations model by entering the Islamic guidelines for redistribution in this model and examine the economic impact of redistributive behavior by analyzing the model in Islamic economics framework. The results show that an increase in redistributive behavior that emerges in the form of in Infaq (Transfer payment), has a positive impact on saving and capital accumulation and therefore is consistent with economic growth. So, one optimal approach for implementation of redistributive justice is to encourage people to Infaq and voluntary donations

Effects of Two Protocols of Low-Level Laser Therapy on the Proliferation and Differentiation of Human Dental Pulp Stem Cells on Sandblasted Titanium Discs: An In Vitro Study: Low-Level Laser Therapy of Stem Cell Activity on Titanium

Introduction: Stem cell activities have different effects on tissue response and its outcomes. Low-level laser therapy (LLLT) can be considered a trigger to modify stem cell activities. The objective of the present experimental investigation was to study the effects of two protocols of LLLT on the proliferation and differentiation of human dental pulp stem cells (hDPSCs) cultured on sandblasted titanium discs.Methods: Cells obtained from human dental pulp were seeded/cultured on titanium discs and were set in 2 main groups: (i) Radiated cells using the gallium-aluminium-arsenide (GaAlAs) diode laser at a continuous wavelength of 808 nm at 3 J/cm2 for 12 sec or 5 J/cm2 for 20 seconds, and (ii) Nonirradiated cells serving as control groups. The impact of LLLTs on hDPSC proliferation and viabilitywas investigated using the MTT assay after 24, 72, and 96 hours. The alkaline phosphatase activity was studied with p-nitrophenylphosphate after 14 and 28 days. The ability of hDPSCs to express osteocalcin was investigated using real-time polymerase chain reaction after 28 days, while their attachment was observed under a scanning electron microscope (SEM) after 14 and 28 days.Results: Our study showed that LLLTs caused maximum cell proliferation in 96 hours (P<0.001) with 3 J/cm2 resulting in a higher proliferation rate. The highest activity of alkaline phosphatase and osteocalcin expression was observed in the laser radiation groups after 28 days.Conclusion: The outcomes of the current study showed that cultured hDPSCs on sandblasted titanium discs had a tendency towards increased cellular activity in response to LLLTs. Thus, LLLTs could regulate the activities of hDPSCs on bone repair surrounding the sandblasted titanium discs. DOI:10.34172/jlms.2022.0

Physicochemical Changes of Contaminated Titanium Discs Treated With Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Irradiation or AirFlow Abrasion: An In Vitro Study: Physicochemical Changes After Decontamination of Titanium Discs

Introduction: Peri-implantitis is a common complication of dental implant treatment. A cause-and effect relationship has been previously documented between microbial plaque and peri-implantitis and implant failure. A difference has been reported in the disinfection efficacy of erbium laser irradiation and air-flow abrasion for contaminated titanium surfaces. Also, the surface changes caused by lasers and air-flow abrasion have not been well studied. Thus, the purpose of this study was to compare the surface changes of contaminated titanium discs following decontamination by erbium-doped yttrium aluminum garnet (Er: YAG) laser irradiation and air-flow abrasion.Methods: Twenty-eight intact, sandblasted, and acid-etched (SLA) titanium discs were used. Twentyfour titanium discs were contaminated with Escherichia coli. Then, they were decontaminated by using Er: YAG laser irradiation and air-flow abrasion. Four discs remained intact. The mean and standard deviation of the contact angle and the weight percentage of aluminum, titanium, oxygen, carbon, phosphorus, and calcium were measured. Qualitative changes in surface topography of titanium discs were assessed by scanning electron microscopy (SEM).Results: The mean weight percentage of carbon in the air-flow abrasion group (4.98%) experienced a significant reduction compared with the contaminated (positive control) group (P=0.035). The contact angles were 46.54° and 38.67° in the laser and air-flow abrasion groups respectively, which were significantly lower than the value in the positive control group (75.15°) (P ≤0.001). SEM micrographs showed no significant change in the surface area in either technique.Conclusion: Air-flow abrasion was more successful in improving the surface characteristics of titanium discs with no alteration in surface topography or elements, compared with Er: YAG laser irradiation. Further studies regarding the safety of the Er: YAG laser for the decontamination of titanium surfaces are recommended. DOI:10.34172/jlms.2021.6