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ObjectiveVaccines against antigens expressed on adenomas could prevent new adenoma formation. We assessed whether a MUC1 peptide vaccine produces an immune response and prevents subsequent colonic adenoma formation.DesignMulticenter, double blind, placebo-controlled randomized trial in individuals age 40-70 with diagnosis of an advanced adenoma ≤1 year from randomization. Vaccine was administered at 0, 2, and 10 weeks with a booster injection at week 53. Adenoma recurrence was assessed ≥1 year from randomization. The primary endpoint was vaccine immunogenicity at 12 weeks defined by anti-MUC1 ratio ≥2.0.Results53 participants received the MUC1 vaccine and 50 placebo. 13/52 (25%) of MUC1 vaccine recipients had a ≥2-fold increase in MUC1 IgG (range 2.9-17.3) at week 12 vs. 0/50 placebo recipients (1-sided Fisher’s exact PConclusionAn immune response was observed only in vaccine recipients. Overall adenoma recurrence was not different than placebo, but a 38% absolute reduction in adenoma recurrence was observed in immune responders.ClinicalTrials.gov Identifier: NCT02134925.https://clinicaltrials.gov/ct2/show/NCT02134925Key PointsWhat is already knownAntigens expressed on colonic adenomas are potential targets for immunopreventive vaccines. An effective vaccine could prevent subsequent adenoma formation.What this Study AddsIn this multicenter, double blind, placebo-controlled randomized trial, MUC1 vaccine recipients developed an immune response. Overall adenoma recurrence was not different than placebo, but a 38% absolute reduction in adenoma recurrence was observed in immune responders.How this study might affect research, practice or policyVaccine immunoprevention is a potential new frontier to colorectal cancer prevention.

Purpose The present in vivo study aimed to estimate the prevalence and variation in anterior loop of inferior alveolar nerve (IAN) in relation to mental foramen to assess the safe zone in anterior part of mandible for implant placement with cone-beam computed tomography (CBCT) in North Indian population. Materials and Methodology To conduct this study, 70 patients were selected and radiographically evaluated. All CBCT scans were made from Genoray Papaya 3D Plus. CBCTs were evaluated in CDSee software for anterior loop and height measurement anterior to mental foramen. Four parameters of prevalence of loop length and height anterior to mental foramen on right and left side each and four parameters of variation in loop length and height on right and left side each were recorded with the help of descriptive statistical analyses (mean, median, mode, and range) and paired t-test. Level of significance (p) was also calculated. Result Paired t-test value for comparison on both the right and left sides for loop length of IAN anterior to mental foramen was 0.140 and paired t-test value for loop height was 0.384. The p-values for loop length and height were 0.8891 and 0.7019, respectively. Conclusion Within the limitation of the study, it was observed that the anterior loop has a wide range of prevalence and variation in terms of loop length and loop height suggesting that it is difficult to get a defined measurement of loop length for a given population and surgical procedures cannot be performed based on the given data for IAN loop anatomy.

Purpose To compare between values of condylar inclination obtained by protrusive interocclusal records using extraoral Gothic arch tracing with cone-beam computed tomography (CBCT) scan, and cephalometric and panoramic radiographs in edentulous patients. Materials and Methods Horizontal condylar guidance angle (HCGA) was measured using the extraoral Gothic arch tracing, CBCT, lateral cephalogram, and orthopantomogram (OPG) in 20 patients aged between 40 and 75 years. HCGAs were determined clinically using protrusive interocclusal records and semi-adjustable articulator after extraoral Gothic arch tracing. Radiographically, Frankfort horizontal plane was marked and a straight line joining the superior-most point and the inferior-most point of posterior slope of the articular eminence (AE) was drawn till the two lines met at an intersection. The angle at this intersection depicted the AE inclination and the angle was measured. Statistical analysis was done using analysis of variance test, multiple comparison was done using Tukey test, and the Pearson correlation coefficient was compiled for different study parameters. Result A significant difference in condylar guidance was observed among different methods (p-value Conclusion It was concluded that horizontal condylar guidance (HCG) values with the radiographic technique were higher than the clinical method. It was observed that mean HCG values were higher by 6.4 degrees in CBCT, 6.7 degrees in OPG, and 9.9 degrees in lateral cephalogram as compared with the clinical value. It was also observed that there was a variation of condylar guidance up to 5 degrees between right and left sides.

Introduction Obtaining an appropriate impression of the implant position and surrounding soft and hard tissues is paramount to fabricating an esthetically and biologically functional definitive restoration. Materials and Methods An edentulous maxillary acrylic master model was chosen. Four dummy implants were drilled into this model from the first premolar to first premolar region at equal distance using a dental surveyor to ensure parallel placement of the implants. Ten samples, each made for open tray (Group A), closed tray direct (Group B), and closed tray indirect (Group C) techniques using polyvinylsiloxane, were poured in type IV dental stone and 30 samples were hence obtained. The linear distance between the four implants were measured using the profile projector for each of the cast. The data obtained were analyzed using ANOVA and Tukey's HSD test. Observation and Results Inter-implant and inter-abutment linear distances were measured (in mm) for the master model and the samples for 1 to 2, 2 to 3, 3 to 4, 1 to 3, 2 to 4, and 1 to 4, and the maximum deviation was found in Group B. Conclusion The dimensional accuracy of casts obtained from closed tray indirect impression technique was the highest with linear distance values closest to the implant master model followed by open tray, and the least accuracy was found for closed tray direct impression technique.

The aim of this article is to present the clinical application of leukocyte-platelet-rich fibrin (L-PRF) at immediately extracted site after the implant placement. A 37-year-old male patient reported to the Department of Prosthodontics, Bhojia Dental college Budh Baddi Dist Solan Himachal Pradesh 173205 with the chief complaint of decayed teeth in the posterior region and wants a fixed prosthesis. On the day of surgery, implants were placed in freshly extracted sockets along with the bone graft and L-PRF membrane. After 6 months of healing period, implant level impressions were made and final porcelain fused to metal crowns were given to the patient.

Search is one of the more common strategies used by problem-solving agents. For many hard problems, a backtracking search can be the most effective approach for finding a solution. Logic programming languages provide, as a core feature of the language, the mechanics for the search behind the scenes without requiring the user to specify the algorithm. However, this functionality has been generally left out of the core features of imperative programming languages. In this work, we propose integrating a search agent into an imperative programming language through a search construct in the syntax. By doing so, our intention is that the user may apply a declarative approach to problem solving. We extend the Go programming language with this search construct and develop an agent to perform the search. The algorithm behind the search is implicitly handled by the agent. We demonstrate the effectiveness of this search construct through solutions to an exhaustive search over a file-system, the NQueens problem, and the monkey and the bananas problem. To evaluate the performance of our agent, we compare its runtime performance against two of the common Prolog implementations, SWI-Prolog and GNU Prolog.

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supplementary methods: Detailed laboratory methods

Purpose:To assess whether MUC1 peptide vaccine produces an immune response and prevents subsequent colon adenoma formation.Patients and Methods:Multicenter, double-blind, placebo-controlled randomized trial in individuals age 40 to 70 with diagnosis of an advanced adenoma ≤1 year from randomization. Vaccine was administered at 0, 2, and 10 weeks with a booster injection at week 53. Adenoma recurrence was assessed ≥1 year from randomization. The primary endpoint was vaccine immunogenicity at 12 weeks defined by anti-MUC1 ratio ≥2.0.Results:Fifty-three participants received the MUC1 vaccine and 50 placebo. Thirteen of 52 (25%) MUC1 vaccine recipients had a ≥2-fold increase in MUC1 IgG (range, 2.9–17.3) at week 12 versus 0/50 placebo recipients (one-sided Fisher exact P < 0.0001). Of 13 responders at week 12, 11 (84.6%) responded to a booster injection at week 52 with a ≥2-fold increase in MUC1 IgG measured at week 55. Recurrent adenoma was observed in 31 of 47 (66.0%) in the placebo group versus 27 of 48 (56.3%) in the MUC1 group [adjusted relative risk (aRR), 0.83; 95% confidence interval (CI), 0.60–1.14; P = 0.25]. Adenoma recurrence occurred in 3/11 (27.3%) immune responders at week 12 and week 55 (aRR, 0.41; 95% CI, 0.15–1.11; P = 0.08 compared with placebo). There was no difference in serious adverse events.Conclusions:An immune response was observed only in vaccine recipients. Adenoma recurrence was not different than placebo, but a 38% absolute reduction in adenoma recurrence compared with placebo was observed in participants who had an immune response at week 12 and with the booster injection.

Endpoint titers of plasma antibodies at week 12 amongst vaccine responders

The CAPP2 trial investigated the long-term effects of aspirin and resistant starch on cancer incidence in Lynch syndrome (LS) patients. Participants with LS were randomised double-blind to 30g resistant starch (RS) daily or placebo for up to 4 years. We present long-term cancer outcomes based on the planned 10 year follow up from recruitment, supplemented by national cancer registry data to 20 years in England, Wales and Finland. Overall, 463 participants received RS and 455 placebo. After up to 20 years follow-up, there was no difference in colorectal cancer (CRC) incidence (n=52 diagnosed with CRC among those randomised to RS against n=53 on placebo) but fewer participants had non-colorectal LS cancers in those randomised to RS (n=27) compared with placebo (n=48); intention-to-treat (ITT) analysis (Hazard Ratio (HR) 0.54 (95%CI 0.33-0.86), p=0.010)). In ITT analysis allowing for multiple primary cancer diagnoses among participants by calculating Incidence Rate Ratios (IRR) confirmed the protective effect of RS against non-CRC LS cancers (IRR 0.52 (95%CI 0.32- 0.84), p=0.0075). These effects are particularly pronounced for cancers of the upper GI tract; 5 diagnoses in those on RS versus 21 diagnoses on placebo. The reduction in non-CRC LS cancers was detectable in the first 10 years and continued in the next decade. For CRC, ITT analysis showed no effect of RS on CRC risk (HR 0.92 (95%CI (0.62-1.34)), p=0.63). There was no interaction between aspirin and RS treatments. In conclusion, 30g daily RS appears to have a substantial protective effect against non-CRC cancers for LS patients.

Introduction This study was undertaken to evaluate the pattern of stress distribution in implant body and surrounding bone with and without splinting of implant prostheses when subjected to occlusal loading, using the finite element analysis. Methods The geometric models of implant and mandibular bone were generated. Two models were created in accordance with the need of the study. The first model was given a two implant in the first mandibular molar and second premolar with splinted prosthesis. Then, second model was given two such implants in the same region but without splinting the prosthesis. Forces of 100 N and 50 N were applied axially and buccolingually, respectively. Results The maximum von Mises stress values with axial force of the implant splinted prosthesis were observed to be 4.21 MPa for cortical bone, 0.88 MPa for cancellous bone, and 10.592 MPa for implant body. The maximum von Mises stress values with buccolingual force of the implant splinted prosthesis were observed to be 9.08 MPa for cortical bone, 1.33 MPa for cancellous bone, and 30.08 MPa for implant body. The maximum von Mises stress values with axial force of the implant nonsplinted prosthesis were observed to be 4.51 MPa for cortical bone, 0.91 MPa for cancellous bone, 13.18 MPa for implant body. The maximum von Mises stress values with buccolingual force of the implant nonsplinted prosthesis were observed to be 9.52 MPa for cortical bone, 1.91 MPa for cancellous bone, 35.04 MPa for implant body. Conclusion The maximum stresses were transferred more to the implant body than to the bone in both the splinted and nonsplinted implant prostheses. The maximum von Mises stresses were observed on nonsplinted implant prostheses, so splinting implant prostheses led to lower stress in the implant body and surrounding bone.

The prosthodontic management of a patient with long-term edentulism is challenging. Conventional dentures have been the traditional standard of care for the longest time. However, most patients experience difficulty in adapting to their mandibular dentures due to lack of stability and retention. From the past two decades, implant-supported overdentures have been offering numerous advantages over the traditional complete dentures and removable partial dentures with predictably good clinical results. These advantages include increased oral function, decreased bone resorption, decreased prosthesis movement, better aesthetics, and maintenance of occlusal vertical dimension. This article presents a case report of fabrication of two-implant overdenture in mandibular knife edge ridge in the anterior mandible opposing conventional maxillary complete denture.

The aim of this article is to present the clinical application of implant placement in the aesthetic zone using bone graft and leukocyte-platelet-rich fibrin to obtain desirable results. A 27-year-old male patient reported with a chief complaint of missing tooth in the anterior region due to trauma and wants to replace it with a fixed prosthesis. The patient had been undergoing orthodontic treatment for the last 3 years. After proper treatment planning, endo-osseous implant followed by alloplastic bone graft was placed and platelet-rich fibrin membrane was placed on the labial bony surface as the labial plate was thin. After 6 months, the prosthetic procedure was done.

Aim and Objective The main aim of this study was to evaluate the effect of three different types of pattern materials on the vertical marginal accuracy of complete cast crown. Material and Methods Three groups of 20 specimens each were made based on three pattern materials, that is, blue inlay wax, autopolymerizing acrylic resin, and light cure pattern resin. Castings were made and examined using stereo microscope for vertical marginal discrepancy. Results The result showed that the highest mean gap was noticed in the castings fabricated using inlay type B pattern wax followed by the castings fabricated using autopolymerizing resin and the least mean gap was observed in the castings fabricated using light cure modeling material. Conclusion It was concluded from this study that the use of light cure modeling material to make patterns for casting with lost wax technique is best recommended than inlay type B pattern and autopolymerizing resin.

Dental implants are fixtures that constitute for the replacements of the root of a missing natural tooth. Dental implant therapy has been widely used for the restoration of partially and fully edentulous patients. The implant literature emphasizes the importance of a passively fitting prosthesis to prevent prosthodontic complications or even loss of fixture integration. Failure to achieve a passively fitting prosthesis and force tightening of superstructure may result in complications such as abutment, framework, and gold screw loosening or fracture. Various materials that can be used for making an implant impression are polyether, polyvinylsiloxane, condensation silicone, polysulfide, irreversible hydrocolloid material, and various others. There are various studies in relation to the accuracy of these impression materials out of which various scientists concluded different results with most studies stating polyether with the maximum amount of dimensional accuracy in comparison to other materials. An accurate implant impression plays a significant role and serves as a starting point in the process of producing good working casts. Thus, the accuracy of impression techniques becomes a significant issue in consideration of passive fit. Reproduction of intraoral relationship of implants through impression procedures is the first step in achieving accurate fit prosthesis. This transference is still complicated by the number, angulation, depth, and position of implants. The advent of computer-aided design/computer-assisted manufacturing technology improved the framework fabrication procedures and has increased the precision of fit of implant prosthesis.

Internet based applications are as a tool progressively used to encourage learning and relationship management in management education. This examination analyzed the attitude of students and educators towards utilizing internet based applications in the management education. Following the literature review that presented 11 internet based applications utilized in classroom settings, questionnaires were distributed to students and educators from three state funded management institutes in Delhi. Responses of 341 management students and 46 faculty members with respect to 5 domains of internet based applications – feedback, classroom management, content creation and publication, communication, and social media – were broke down to explore the attitude towards utilization of internet based applications. The outcomes uncovered that students apparent the internet based applications of communication and social media to be useful in learning and in expanding their future skills; likewise, the educators observed these internet based applications to be valuable.

Aim The aim of this study was to evaluate the distribution of stresses in osseointegrated crestal and basal implant in zygomatic region of maxilla and to identify the preferable implant option for better stress distribution. Material and Method The present in vitro study was performed to evaluate stress patterns in bone around basal and crestal dental implant under axial and oblique loading in maxillary zygomatic region with the help of a finite element analysis (FEA). To conduct this study, the following materials were used: computer software ANSYS, basal implants with dimensions 3.7 × 10 mm, and crestal implants with dimensions 3.7 x 10 mm. The amount of load transferred on the bone adjacent to the implant in an axial and transverse load of 100 N at 0 and 45 degrees, respectively, was placed on both types of implants. A three-dimensional (3D) scanner was use to generate 3D simulated model of basal and crestal implants. FEA modelling was generated that replicated the zygomatico maxillary region with special emphasis on bone architecture, bone density, angulation, width, and length of implant prototype. Further, material properties were defined for cortical bone, dense trabecular bone, low density trabecular bone, and titanium on the basis of Young’s modulus of elasticity. Results These values were used by FEA software (ANSYS) to generate a 3D mesh model of bone and implant. Finally, Von Mises (equivalent stress) (MPa) values on the implant were computed using FEA software. The values of maximum Von Mises equivalent stress on the implant collars, body, apex, and bony interface were obtained. Conclusion Maximum stresses were seen at the cortical bone with basal implant placed inside the bone. Stresses that are transferred more to the bone through implant promote bone remineralization. Maximum Von Mises stresses were observed on basal implant body. Thus, these greater stresses have the capacity to simulate mineralization in the cortical bone; this makes basal implant a suitable option for placement inside the cortical bone.

Immediate loading of dental implant in the anterior tooth region has been a growing trend and eliminates the compromised esthetics, function, discomfort, and inconvenience associated with traditional two-stage implant procedures. This case report presents the clinical application of implant placement with immediate loading using leukocyte-platelet-rich fibrin (L-PRF) in the anterior esthetic region. The implant was planned to rehabilitate in the anterior missing tooth region. As per the patient's desire, the implant was immediately loaded and L-PRF membrane was placed around the implant under local anesthesia on the day of surgery. The use of L-PRF for the maintenance of crestal bone and soft tissue at the implant sites provided an adequate clinical condition for better esthetics.

Aim The purpose of this study was to compare and evaluate the flexural strength and modulus of elasticity of three adhesive luting cements as a function of specimen age, effect of storage media, and effect of curing through porcelain. Materials and Methods Twenty samples fabricated for self-cure resin-modified glass ionomer cement (GIC; RelyX Luting 2, 3M ESPE, United States) were classified as group 1, whereas 40 samples fabricated for two dual-cure resin cements (20 samples each), Universal Resin Cement (Ammdent, Italy) and Maxcem Elite (Kerr Australia Pty. Ltd.), were classified as groups 2 and 3, respectively. The dual-cure cements were photo-activated using light cure unit with an intensity of 550 mW/cm2 in nine overlapping sections for 20 seconds per section on both sides. A total of 60 samples (20 samples in each group) were fabricated and tested using universal testing machine to compare flexural strength and modulus of elasticity of resin-modified GIC with two dual-cure adhesive resin cements, to determine the influence of storage of the specimens in artificial saliva at 37°C for 24 hours and to determine the influence of curing through porcelain disk of 2 mm thickness on these properties. Results The overall mean flexural strength and modulus of elasticity of resin-modified GIC was less than the dual-cure resin cements. The values reduced for resin-modified GIC when the samples were tested after 24 hours of storage in saliva, whereas an increase in the strength was seen for dual-cure cements. The curing through porcelain disk reduced the properties of dual-cure cements. Maxcem Elite showed better overall mean flexural strength and modulus of elasticity in all the parameters. Conclusion When comparing all three cements, both dual-cure cements showed better flexural strength and modulus of elasticity compared to resin-modified GIC, which indicates their use in cementation of fixed restorations.

The conventional crestal implants are used only when there is adequate jawbone height and width. Results of conventional implants are good in patients with healthy bone at the time of treatment, but prognosis gets deteriorated when surgical augmentation of bone is included with implant placement. These augmentation procedures have surgical risks and are costlier to the patients. Patients with atrophied jawbones are given no treatment, until crestal implants are seen as the last option. In this article, the indications for basal implants and functional differences between basal implants and crestal implants have been discussed.Patients with extreme jawbone atrophy do not benefit from crestal implants. The basal bone is the (cortical) osseous tissue of the mandible and maxilla, and lies below the alveolar process, which has a relatively strong and no resorbing framework.Basal osseointegrated and basal cortical screw (BCS) are two types of implants designed to take anchorage from the cortical bone of the jaw. BCS implants have long shafts and can be placed immediately in the socket after extraction and provided with immediate loading within 72 hours of implant placement. Basal implants are also called bicortical or cortical implants as they utilize the cortical portion of the jawbones for anchorage and implant stability. The basal bone has better quality and quantity of cortical bone for retention of these unique and highly advanced implants. The other names for these implants are lateral implants or disk implants.

In medical disease diagnosis, the cost of a false negative could greatly outweigh the cost of a false positive. This is because the former could cost a life, whereas the latter may only cause medical costs and stress to the patient. The unique nature of this problem highlights the need of asymmetric error control for binary classification applications. In this domain, traditional machine learning classifiers may not be ideal as they do not provide a way to control the number of false negatives below a certain threshold. This paper proposes a novel tree-based binary classification algorithm that can control the number of false negatives with a mathematical guarantee, based on Neyman–Pearson (NP) Lemma. This classifier is evaluated on the data obtained from different heart studies and it predicts the risk of cardiac disease, not only with comparable accuracy and AUC-ROC score but also with full control over the number of false negatives. The methodology used to construct this classifier can be expanded to many more use cases, not only in medical disease diagnosis but also beyond as shown from analysis on different diverse datasets.

The pathogenesis of subsquamous intestinal metaplasia (SSIM), in which glands of Barrett’s esophagus (BE) are buried under esophageal squamous epithelium, is unknown. In a rat model of reflux esophagitis, we found that columnar-lined esophagus developed via a wound-healing process involving epithelial-mesenchymal plasticity (EMP) that buried glands under ulcerated squamous epithelium. To explore a role for reflux-induced EMP in BE, we established and characterized human Barrett’s organoids and sought evidence of EMP after treatment with acidic bile salts (AB). We optimized media to grow human BE organoids from immortalized human Barrett’s cells and from BE biopsies from seven patients, and we characterized histological, morphological, and molecular features of organoid development. Features and markers of EMP were explored following organoid exposure to AB, with and without a collagen I (COL1) matrix to simulate a wound-healing environment. All media successfully initiated organoid growth, but advanced DMEM/F12 (aDMEM) was best at sustaining organoid viability. Using aDMEM, organoids comprising nongoblet and goblet columnar cells that expressed gastric and intestinal cell markers were generated from BE biopsies of all seven patients. After AB treatment, early-stage Barrett’s organoids exhibited EMP with loss of membranous E-cadherin and increased protrusive cell migration, events significantly enhanced by COL1. Using human BE biopsies, we have established Barrett’s organoids that recapitulate key histological and molecular features of BE to serve as high-fidelity BE models. Our findings suggest that reflux can induce EMP in human BE, potentially enabling Barrett’s cells to migrate under adjacent squamous epithelium to form SSIM. NEW & NOTEWORTHY Using Barrett’s esophagus (BE) biopsies, we established organoids recapitulating key BE features. During early stages of organoid development, a GERD-like wound environment-induced features of epithelial-mesenchymal plasticity (EMP) in Barrett’s progenitor cells, suggesting that reflux-induced EMP can enable Barrett’s cells to migrate underneath squamous epithelium to form subsquamous intestinal metaplasia, a condition that may underlie Barrett’s cancers that escape detection by endoscopic surveillance, and recurrences of Barrett’s metaplasia following endoscopic eradication therapy.

Introduction Provisional restoration is a critical component of fixed prosthodontics treatment, which must satisfy many inter-relative factors such as biological, mechanical, and esthetic. These restorations should have accurate marginal adaptation and optimum strength to maintain functional demands. The present “in vitro” study was conducted to evaluate the effect of water temperature and duration of immersion, on the marginal adaptation and microhardness of four different commercially available provisional restorative materials. Materials and Methods The 240 specimens were then seated on the stainless-steel die which simulated the prepared tooth, and evaluated for the marginal gap for four different provisional restorative materials and divided into four different groups A, B, C, and D. Each group was further divided into six subgroups according to temperature of water and time of immersion. In each group the samples were immersed in water at 20, 30, and 40 degrees, respectively for 5 and 10-minutes duration. Four different temporary restorative materials for crown fabrication were loaded each time to make temporary crowns. Results Each sample was placed under travelling stereoscopic microscope (20× magnification) and photographed. Results for each surface were obtained, and the average of three surfaces was calculated. Knoop hardness was measured using a microhardness tester. The study was subjected to statistical analysis, to know the statistical significance, of the effect of difference in time and temperature changes at the time of final polymerization on surface microhardness and marginal integrity of four different provisional restorative materials. Discussion The mean marginal discrepancies of bis-GMA (group B) at 20, 30, and 40°C for 5 and 10 minutes in water were smaller than the results of other groups. Microhardness evaluation showed that the poly ethyl methacrylate (PEMA) type resin exhibited significantly lower microhardness than the bis-acryl resin composites (Protemp 4 and Systemp.c&b) at both time and temperature intervals. Conclusion The bis-acryl composites material has the least marginal discrepancy in comparison with PEMA and polymethyl methacrylate (PMMA). The bis-acryl composites materials exhibit superior surface microhardness followed by PEMA and PMMA.

Introduction Luting cements are susceptible to attack by moisture during the initial setting period that can result in an increased solubility. The aim of this in vitro study was to evaluate the solubility of different permanent and temporary dental luting cements in artificial saliva of different pH values at different time intervals. Materials and Methods Eight commercial luting cements were used. Out of which five were permanent cements (Rely X lute2, zinc phosphate cement, zinc polycarboxylate cement, Rely X U-200, GC GIC) and three temporary cements (ZOE, Oratemp NE, Temposil). A total of 200 samples were made into 25 specimens of each cement (five samples for each study solution group). The samples were made of dimension 20 mm × 1.5 mm in the metal mold. Once the cements were set, they were removed and after 3 minutes of removal they were placed in the incubator at 37°C ± 1 for 1 hour. Specimens of each cement type were separated into five groups for evaluation and comparison in distilled water and artificial saliva with four different pH values (pH 3, pH 5, pH 7, and pH 9). Percentage of solubility was calculated as 100% times weight loss divided by initial weight of the specimen. Results When all permanent cements were tested the result showed that Rely X U-200 showed least dissolution even after 28 days, followed by Rely X lute-2, then Glass ionomer cement then zinc polycarboxylate cement and then zinc phosphate cement which gave maximum dissolution. Conclusion When all temporary cements were tested the result showed that Temposil showed least dissolution even after 28 days, followed by OraTemp NE, compared with zinc oxide eugenol which gave maximum dissolution.

Introduction This study was undertaken to assess the influence of different superstructure materials, when subjected to occlusal loading, on the pattern of stress distribution in tooth-supported, implant-supported, and tooth implant-supported fixed partial prostheses, using the finite element analysis with a comparative viewpoint. Materials and Methods The geometric models of implant and mandibular bone were generated. Three models were created in accordance with the need of the study. The first model was given a tooth-supported fixed partial prosthesis. The second model was given tooth implant-supported fixed partial prosthesis, and the third model was given implant-supported fixed partial prosthesis. Forces of 100 N and 50 N were applied axially and buccolingually, respectively. Results The present study compared the stresses arising in the natural tooth, implant, and the whole prostheses under simulated axial and buccolingual loading of three types of fixed partial dentures, namely, tooth-supported, tooth implant-supported, and implant-supported fixed partial dental prostheses using three different types of materials. Conclusion The pattern of stress distribution did not appear to be significantly affected by the type of prosthesis materials in all models. The maximum stress concentrations were found in the alveolar bone around the neck of the teeth and implants.

Introduction Replacing missing anterior teeth with a prosthesis that resembles natural form and function has always been challenging for a prosthodontist. Removable and fixed options both have been extensively studied and researched upon. In modern dentistry, implants have proved to be a more logical option for the same. The morphology of bone present in the premaxilla serves as guide to plan implant angulation during osteotomy. Factors such as age-related bone resorption, trauma or pathologic bone resorption due to periodontitis, etc. causes implants to be placed at angles that are difficult to restore with conventional straight abutments. Angled abutments can help build up favorable functional prosthesis in such cases, but they experience the drawback of transferring unfavorable forces to the implant or bone, thereby compromising the prognosis of the treatment. Clinically, the effect of these forces is difficult to evaluate, so a finite element analysis was done to estimate stress distribution at the bone implant interface. Materials and Methods In this study, premaxilla was modeled with 15 mm in bone height, 7 mm in bone length, and 12 mm in bone width with 1.5 mm thick cortical bone surrounded by a core of cancellous bone. The implant was modeled as a cylindrical, round-ended device with dimensions, 4.3 mm × 11.5 mm. Abutments with angulations 0°, 10°, 15° and 25° were used. To simulate clinical conditions, a 100 N load axially and 30 N load obliquely was applied. Result It was seen that, as the abutment angulation changes from 0° to 25°, both the compressive as well as tensile stresses increased; however, they were within the tolerance limit of the bone. Conclusion The study suggests angled abutments can be used with reasonable success, keeping in mind the basics of implant prosthodontics intact.

Introduction The overdenture is an alternative to fixed implant-supported prosthesis for its relatively low-cost and in clinical cases where it is impossible to place multiple implants with appropriate number and arrangement in the arch to support a fixed prosthesis. In implant-supported overdentures, many attachments such as bars, ball, and magnets can be used. The anchorage system affects the retention and stability of the overdenture as well as the load transfer to the implant and the bone. The purpose of this study was to evaluate the exerted stresses on implants and implant–abutment interface by comparing different attachment systems used for implant-supported maxillary and mandibular overdentures using finite-element analysis. Materials and Methods Stress distribution in five different models with different attachments were evaluated using finite-element analysis. The studied attachment systems were Ball/O-ring and bar-clip attachments. Three models in mandible were studied, two implants with ball attachments, two implants with bar, and four implants connected with a bar. In maxilla, two models were studied, four implants with ball attachments, and four implants connected with bar. Forces were applied bilaterally on each model in the canine and molar region separately. The forces applied were 35N axially, 70N obliquely, and 10N horizontally. Results The ball attachments models showed the highest amount of stresses on the bone and on the implants in maxilla and mandible. The bar-clip attachment with four implants showed least stress in maxilla as well as in the mandible. The bar on four implants has better stress distribution as compared with the bar on the two implants.

Introduction Marginal bone level is the criterion for implant success. Patient expectations for more natural looking implant restorations created the need to restore implants with more esthetically pleasing materials like Zirconia rather than conventional porcelain-fused to-metal (PFM) crowns. The aim of this study was to evaluate marginal bone loss around dental implants clinically and radiographically when restored with Zirconia and PFM prosthesis. Materials and Methods Two groups (control and test) were formed with 14 patients each. In the control group, the subjects were rehabilitated with PFM crowns and in the test group, the subjects were rehabilitated with Zirconia crowns. Rehabilitation was done after the healing period of 3 months. Radiographic evaluation was done at regular (baseline, 3rd, 6th, and 12th month) intervals. Results The results were statistically analyzed. Keeping in mind the limitations of the study, it was revealed that the difference in the crestal bone resorption in both the groups was not significant.

Introduction Dental implants are common treatment modality for tooth loss which leads to unaesthetic appearance and may also cause deterioration of mastication and speech. The aim of implant therapy in dentistry is to restore tissue contour, function, comfort, aesthetic, and speech. Dental implant role is to transfer the mechanical force created during chewing to the supporting osseous tissues within the mandible and maxilla. The importance of biomechanical factors such as the bone-implant interface, implant thread design, the length and diameter of implants, type of loading, the quality and quantity of surrounding bone have been strained by various authors. The selection of implant thread design plays an important role in the outcome of the treatment. This study was done to evaluate the influence of different thread designs on stress distribution of osseointegrated implant using three-dimensional (3D) finite-element analysis. Materials and Methods Three implants with different thread designs, namely V-thread, buttress, and reverse buttress thread designs were considered and dimensions were standardized. The site considered was the mandibular molar region with cortical and cancellous bone assuming to be isotropic and homogeneous. The implant modeling was done with the ANSYS 18.1 software. Axial load (100N) and buccolingual load (50N) were applied. The stresses were calculated as Von Mises stress criterion. Results Minimum von mises Stress concentration was seen for tapered implant body with reverse buttress thread design under axial load 100N and tapered implant body with V-thread under buccolingual load of 50N at cortical bone which signifies bone preservation. Stress levels were observed maximum at implant and minimum at the cancellous bone. Conclusion Hence, within the limitations of this study the results obtained can be applied clinically for appropriate selection of implant thread design for a predictable success of implant therapy.