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Objective Myofascial pain syndrome with trigger points is the most common cause of nonodontogenic pain. Although injection of the trigger points is the most effective pain reduction treatment, many patients exhibit recurrence after a short period. Therefore, the aim of the current study was to evaluate the clinical efficacy of magnesium sulfate injections in the treatment of the masseter muscle trigger points when compared to saline injections. Material and method This study randomly (1:1) assigned 180 patients to one of two treatment groups based on whether their trigger points were injected with 2 ml of saline or magnesium sulfate. Pain scores, maximum mouth opening (MMO), and quality of life were measured at the pre-injection and 1, 3, and 6 months post-injection. Results The pain scores were significantly higher in the saline group during all follow-up assessments, whereas the MMO was significantly higher in the magnesium sulfate group up to 3 months of follow-up (p < 0.001). However, the difference in MMO ceased to be statistically significant after 6 months of follow-up (p = 0.121). Additionally, the patient’s quality of life score was significantly higher in the magnesium sulfate group compared to the saline group (p < 0.001). Conclusion Injection of magnesium sulfate is an effective treatment measure for myofascial trigger points. However, further studies with a proper design addressing the limitations of the current study are necessary. ClinicalTrials: org (ID: NCT04742140) 5/2/2021.

Purpose:The purpose of the present study was to analyze the effect of non-thermal air plasma treatment on shear bond strength and failure mode of self-adhesive resin cement to zirconia.Materials& Methods: Forty eight zirconia plates were prepared from IPS e.max ZirCad blocks (Ivoclar Vivadent, Schaan, Liechtenstein) and classified into four groups (n=12) according to surface treatment; group CO (control) without any surface treatment, group SD was treated with 50 µm alumina sandblasting, group PL used air atmospheric pressure plasma device (Piezobrush® PZ2, Relyon plasma GMBH, Regensburg, Germany) & group SP which was a combination of 50 µm alumina sandblasting followed immediately with atmospheric plasma treatment. Zirconia specimens were immediately centered with Relay X Unicem (3M ESPE) resin cylinders of 3.7 mm diameter and 2 mm height. Shear bond strength test was performed 8 days after water storage at 37˚C using a computer controlled materials testing machine (Model 3345; Instron Industrial Products, Norwood, USA). A scanning electron microscope (Quanta 250 Field Emission Gun, Netherlands) was used to determine failure mode with all morphological and structural changes. Average surface roughness (Ra) was calculated with different surface treatments. Energy Dispersive X-ray (EDX) analysis was used for chemical changes evaluation. Data were analyzed with one-way ANOVA followed by Tukey's post hoc test when the ANOVA test was significant.Results: A significant difference between different surface treatments (P=0.010) was recorded with the highest shear bond strength value in SP group and the lowest value with untreated surface CO gp. All groups showed mixed failure mode which was mainly cohesive except for CO gp. Surface roughness was increased with sandblasting and decreased after plazma treatment. EDX analysis showed increase oxygen on plazma treated surface. Conclusion:Non thermal air plasma treatment can be used for increasing zirconia surface treatment especially when accompanied with 50 µm AL 2 O 3 sandblasting.Clinical significant: Non thermal air plasma treatment alone or in combination with sandblasting can be considered as a good clinical protocol for cementing zirconia restorations.

Statement of the problem: researches studying the accuracy of the 3D printed dies were very rare. Aim:The aim of the current study was to assess the difference in accuracy and reproducibility of the three dimensionally printed dies versus the stone dies. Materials& Methods:A maxillary typodont (D13PP-TR.1; Nissan, Kyoto, Japan) model with missing upper 1st molar was prepared as master model. Two types of dies were obtained from the master model (n=6). Group 1 was the conventional stone dies using type IV stone (GC FujiRock EP; GC) while group 2 representing the 3D printed dies (Dent2 Mogassam LLC Co. Egypt, Cairo) using resin (industrial blended resin, Funtodo Co. Netherlands). All working models were scanned (Open Technologies 3D scanner, Brescia, Italy) and STL file was superimposed on the STL file of the master model with the best-fit alignment method to analyze the volumetric changes and color maps were provided using 3Shape 3D software software. The mean average distance between the master dies and the working dies in all groups was recorded. Data were fed to the computer and analyzed using IBM SPSS software package version 20.0. Quantitative data were explored for normality using Kolmogorov-Smirnov and Shapiro-Wilk tests.Results: There were no statistically significant differences in volumetric discrepancies between stone model (0.186±0.231) mm 3 as a (mean±SD) and 3D printed model (0.176±0.211) mm 3 as a mean±SD. Conclusion:Digital work flow can eventually replace the conventional techniques with minimal volumetric discrepancies in 3D printed dies.

Purpose:The purpose of the present study was to investigate the micro-shear bond strength and failure mode of novel "MDP calcium-fluoride releasing" self-adhesive resin cement (TheraCem) with tooth structure (enamel& dentin) and yttrium stabilized zirconia after thermocycling and comparing the results with universal "non-containing MDP" self-adhesive resin cement (Relay X Unicem as a control) Materials and Methods: Enamel and dentin specimens (20 discs each) were obtained by using diamond saw (IsoMet 4000 linear Precision saw, Buehler, USA) with copious water coolant. Twenty zirconia plates were obtained from IPS e.max ZirCad blocks (Ivoclar Vivadent, Schaan, Liechtenstein) and sintered in an inFire HTC speed high-temperature furnace (Sirona Dental System GmbH, Germany). Micro resin cylinders were created on the bonded surface and filled with the tested cements (n= 10 /substrate) group A (control) using non-containing MDP selfadhesive cement Relay X Unicem (3M ESPE) while group B (tested cement) using MDP calciumfluoride releasing self-Adhesive resin cement TheraCem (BISCO, Schaumburg, Illinois, USA). Cements were left to self-cure for 5 minutes. All the specimens were thermocycled for 5,000 cycles (Thermocycler 1100 SD Mechatronik, GmbH). Micro-shear bond strength was measured using universal testing machine and debonded surfaces were examined for failure mode analysis with all morphological and ultrastructure changes using Scanning Electron Microscope (Quanta 250 Field Emission Gun, Netherlands) attached with EDX Unit (Energy Dispersive X-ray Analyses). The results were statistically analysed.Results: TheraCem (tested cement) had a slightly higher (mean±SD) µ-SBS (Mpa) value than RelyX (control) (18.96±4.36, 12.18±3.13; respectively) (P=0.177). Within enamel, TheraCem (6.46±1.37) had a significantly higher (mean±SD) µ-SBS (Mpa) value than RelyX (3.04±0.99) (P=0.002). Similarly, TheraCem in dentine (10.67±1.27) had a significantly higher (mean±SD) than RelyX (6.46±1.74) (P=0.014). As for zirconia, TheraCem (39.76±1.18) had a significantly higher (mean±SD) µ-SBS (Mpa) than RelyX (27.04±1.92) (P<0.001) (822)