Optimization of Monolayer MoS2 with Prescribed Mechanical Properties

Various technological challenges are essentially material problems in our times. New functional and functional graded nanomaterials are constructed of components with predefined properties. The design of nanostructures with predefined mechanical properties was considered in this paper. This study applies the evolutionary algorithm (EA) to the optimization problem in the design of nanomaterials. The optimal design combined EA with molecular dynamics to identify the size of the void for the prescribed elastic properties in monolayer 2D MoS₂ nanostructures. The numerical results show that the proposed EA and the use of optimization method allowed accurately obtaining nanostructures with predefined mechanical material properties by introducing elliptical voids in the 2D MoS₂ nanosheets.     

A clinical evaluation of three topical anaesthetic agents

This study compared the efficacy of EMLA 5% Cream, Xylocaine 5% (lignocaine 5 per cent) and NUM (benzocaine 15 per cent, amethocaine 1.7 per cent) to a placebo in reducing the pain experience during needle insertion. In a random, double blind study three groups of twenty volunteers each had a paired topical anaesthetic/placebo placed bilaterally in the buccal sulcus of the upper premolar regions for two minutes, followed by the insertion of a standard 27 gauge needle to a depth of 5 mm. Pain experience was measured with visual analogue scales. Results showed that all three agents significantly reduced pain when compared with the placebo--EMLA (p less than 0.002); Xylocaine (p less than 0.05); NUM (p less than 0.005).     

The Accuracy of Six Impression Techniques for Osseointegrated Implants

Purpose Six impression techniques were evaluated using tapered and square impression copings. Materials and Methods The absolute distortion was measured using a cast metal impression tray with fiduciary reference points external to the impression material. Measurements of the x, y, z coordinates on the master cast and the impressions were directly made with a travelling digitizing microscope. The difference between the coordinates of each of six sites in the impression and the corresponding reference site were compared. Results There was no significant difference between the techniques for the square copings but that there was a significant loss of accuracy in the z-axis with the tapered copings. Conclusions No significant differences were noted.     

Evidence Regarding the Treatment of Denture Stomatitis

Denture stomatitis is a common inflammatory condition affecting the mucosa underlying complete dentures. It is associated with denture microbial biofilm, poor denture hygiene, poor denture quality, and nocturnal denture use. Numerous treatment methodologies have been used to treat stomatitis; however, a gold standard treatment has not been identified. The aim of this systematic review is to report on the current knowledge available in studies representing a range of evidence on the treatment of denture stomatitis.     

The Change in Retentive Values of Locator Attachments and Hader Clips over Time

Purpose: The aim of this study was to examine early changes in retentive values of implant overdenture attachments during multiple pulls.
Materials and Methods: Two implant attachment systems (Hader bar and clip, Locator system) were used in this study. The experimental groups were divided into yellow Hader clips, white Locator attachments, and green Locator attachments. Each group consisted of 21 matrix attachments. The attachments were placed into a custom-made acrylic resin block seated passively on another acrylic block containing a Hader bar or two Locator abutments with different angulations. Each attachment was subjected to 20 consecutive pulls using a universal testing machine. The peak load-to-dislodgement of the attachments after each pull was documented, and the percent reduction of the peak load-to-dislodgement was calculated. One-way ANOVA and Tukey's honestly significant difference test were used for data analyses. A p ≤ 0.05 was considered significant.
Results: There was a significant difference in the percent reduction in peak load-to-dislodgement between the attachments after the first pull ( p = 0.005) and after the final pull ( p = 0.0001). The yellow Hader clips exhibited the least percent reduction in peak load-to-dislodgement (6.50 ± 3.59%) after the first pull, followed by the white Locator attachments (8.60 ± 4.42%); the green Locator attachments exhibited the greatest reduction (11.05 ± 4.94%).
Conclusion: The results of this in vitro study demonstrate that retentive values of the Locator attachments are reduced significantly after multiple pulls. Although this reduction might not be noticeable to the patient, it is recommended that the clinician place and remove the overdenture multiple times before delivery.     

Osteotome Maxillary Sinus Lift Using Bovine Bone and Calcium Sulfate: A Case Series

Purpose: The purpose of this longitudinal study was to evaluate the success of bovine bone and calcium sulfate (CaSO₄) as sinus augmentation material with osteotome maxillary sinus lift. Materials and Methods: Thirty‐one osteotome sinus lift procedures were performed for 18 healthy patients (7 males and 11 females). A mixture of bovine bone and CaSO₄ (ratio, 4:1) was used as sinus augmentation material with simultaneous implant placement. Implants were loaded 4 to 5 months postimplant surgery. Cases were followed for an average of 23.4 months postloading (range, 12–60 months). Results: The mean age of the study group was 49.7 ± 10.66 years. The residual height of the alveolar ridge ranged from 5.5 to 11 mm (mean, 8.16 ± 1.52 mm). Four to 5 months after implant placement, the x‐ray showed a 1.5 to 5 mm apical shift of the sinus floor (mean, 3.47 ± 0.97 mm), which was maintained to the end of the evaluation period. At 12 months postloading, crestal bone loss ranged from 0.5 to 1.5 mm (mean, 0.87 ± 0.26 mm), and pocket depth ranged from 2 to 4 mm (mean, 2.9 ± 0.67 mm). No significant change in crestal bone loss or pocket depth was noticed afterward. Conclusion: Bovine bone plus CaSO₄ can be used successfully as a sinus augmentation material with osteotome sinus elevation. The use of CaSO₄ significantly improved the handling properties of bovine bone and helped to stabilize the bone graft particles during healing.     

Activation of ethylenediaminetetraacetic acid by a 940 nm diode laser for enhanced removal of smear layer

Laser enhancement of ethylenediaminetetraacetic acid with cetrimide (EDTAC) has previously been shown to increase removal of smear layer, for middle‐infrared erbium lasers. This study evaluated the efficiency of EDTAC activation using a near‐infrared‐pulsed 940 nm laser delivered by plain fibre tips into 15% EDTAC or 3% hydrogen peroxide. Root canals in 4 groups of 10 single roots were prepared using rotary files, with controls for the presence and absence of smear layer. After laser treatment (80 mJ pulse^?1, 50 Hz, 6 cycles of 10 s), roots were split and the apical, middle and coronal thirds of the canal were examined using scanning electron microscopy, with the area of dentine tubules determined by a validated quantitative image analysis method. Lasing EDTAC considerably improved smear layer removal, while lasing into peroxide gave minimal smear layer removal. The laser protocol used was more effective for smear layer removal than the ‘gold standard’ protocol using EDTAC with sodium hypochlorite (NaOCl). In addition, lasers may also provide a benefit through photothermal disinfection. Further research is needed to optimise irrigant activation protocols using near‐infrared diode lasers of other wavelengths.     

Skin Graft Review in Dermofasciectomy for Dupuytren’s Contracture within 48 Hours: Challenging Historical Practice

Introduction  Early review of skin graft following dermofasciectomy with skin grafting for Dupuytren’s disease is not standard practice because of the potentially adverse effects on inosculation and neovascularization process of the skin grafting. The purpose of this retrospective case series was to observe whether early review of grafts postoperatively at 48 hours adversely affects graft survival and surgical outcomes. Materials and Methods  Forty-nine primary and revision procedures were retrospectively analyzed for treatment outcomes, postoperative complications, functional hand scoring, and satisfaction rates postoperatively. Results  Thirty-eight patients were treated successfully with no postoperative contracture. There were three treatment failures and two graft failures, with two amputations within these failures. Paired pre- and postoperative Unité Rhumatologique des Affections de la Main scoring demonstrated significant improvement in hand function for primary procedures, with a mean satisfaction score of 7.7 out of 10. Conclusion  We have shown early graft review following dermofasciectomy and full-thickness skin grafting to be safe, allowing early mobilization and splinting, with our postoperative failure and complication rate being within published literature.