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Digital recording of the maxillomandibular relationship by using intraoral scanning in completely edentulous patients for computer-aided design and computer-aided manufacture implant-supported prostheses can be challenging. This clinical report describes the fabrication of complete-arch, screw-retained implant-supported prostheses in a completely edentulous patient with a fully digital workflow.

Purpose This study was conducted to radiographically evaluate the effect of two different superstructure CAD/CAM fabricated materials, on crestal bone loss around immediately loaded implant. Materials and Methods A total of twelve healthy patients having mandibular bilateral missing first molars with acceptable bone volume were selected based on specific inclusion and exclusion criteria, each patient received a CAD/CAM monolithic zirconia, in one site, while the other site received a CAD/CAM Enamic superstructure, in 48 hours after implant insertion. Implants and abutments were examined for stability, gingival and periodontal health prior to crown cementation. Radiographic evaluation was done immediately at the time of crown cementation then at 6 and 12 months. Results Marginal bone loss was measured at two points, the most buccal crestal bone, and the most lingual crestal bone. Radiographic results showed no significant difference regarding mean MBL between Zirconia and Enamic on 6 and 12 months. Conclusion Immediate loading of a single mandibular molar implant with the final restoration seem to be a reliable technique when certain parameters are respected. Type of implant superstructure material has no significant influence on the bone supporting the implant within the time period of this study.

The strain developed around implants with angled abutments should be considered when selecting a superstructure material. Studies that evaluated the strain developed around implants with angled abutments when using fiber-reinforced polymer as the implant superstructure material are lacking.The purpose of this in vitro study was to assess the strain developed around implants with angled abutments (15 and 25 degrees) of biocompatible high-performance polymer (BioHPP) and reinforced nanohybrid polymer with a multilayered glass fiber (TRINIA) superstructure under axial and oblique loading. The strain developed around implants was evaluated by using strain gauges.Thirty-two polyurethane test blocks were divided into 2 main groups (n=16) according to the degrees of buccal tilting of the implant platform (15 and 25 degrees). Each group was divided into 2 subgroups (n=8), and each subgroup received different superstructure materials (BioHPP or TRINIA). Two buccal and palatal strain gauges were installed on their corresponding prepared sites to measure the microstrains in the medium surrounding the implant. A universal testing machine was used to apply the static load from 0 to 100 N in the axial and 45-degree oblique direction, with the loading tip of the device on the loading point at the central fossa of the crown. For each tested implant, loads were applied, microstrains were recorded with the strain gauges, and the strain developed around the implant was statistically evaluated with 1-way ANOVA, followed by multiple pairwise comparisons by using the Bonferroni adjusted significance level (α=.05).For superstructure materials, the microstrain values recorded around implants restored with TRINIA were significantly lower than those restored with BioHPP in all groups (P.001). The 25-degree implant angulation recorded significantly higher microstrain than 15 degrees buccally and palatally when axial and oblique loads were applied (P.05). The microstrain was significantly higher in the oblique load than in the axial load in both the BioHPP and TRINIA groups in 15- and 25-degree implant angulations on the buccal and palatal sides (P.001).The strain developed around dental implants was significantly affected by the superstructure material. The microstrain was considerably higher when the implant abutment angulation increased. When a 45-degree loading direction was used, this tendency became more pronounced.

more predictable prosthetic outcomes than non-guided implant surgery. OBJECTIVES: To compare the accuracy of implant placement using 3D printed and machine milled surgical guides. MATERIALS AND METHODS: Twelve polyurethane foam resin mandibular models were used in this study. Implant position was virtually planned using 3D planning software based on the preoperative CBCT of each model. Surgical guides were designed on the software and exported in STL format. Models were randomly divided into 2 groups (n=6 each). Group I: Surgical guides were manufactured using 3D printing. Group II: Surgical guides were manufactured using machine milling. Three implants were placed in each model using CAD/CAM surgical guides. The 3D position of the planned and placed implants, in terms of the linear deviations of the implant head and apex and the angular deviations of the implant axis, was compared by superimposing the pre- and postoperative CBCT using dedicated software. The MannWhitney U test was used for comparison (P

CONSERVATIVE APPROACH FOR MANAGEMENT OF POSTERIOR ATROPHIC MAXILLA USING IMPLANT ASSISTED OVERDENTURE (CLINCAL TRIAL) Nayrouz A. Metwally1* BDS,MSc, Ahmed M. Abdel-Hamid2 BDS,MSc,PhD, Ahmed M. Hommos3BDS,MSc,PhD, Nermeen A. Rady4 BDS,MSc,PhD ABSTRACT Introduction: Implant assisted prostheses provide a higher degree of patient satisfaction than traditional prostheses. However, severe atrophy of the edentulous maxilla and maxillary sinus pneumatization may reduce the available bone in the posterior region for a safe and reliable implant‑supported dental rehabilitation. Tilted implants in the anterior region of the maxilla were suggested to be useful in the treatment of posterior atrophic edentulous maxilla that allows the use of longer implants to gain more stability. This may preclude the use of conventional Implant overdenture abutments, requiring the use of divergence correcting attachments. Objectives: The aim of the present study was to clinically evaluate the effect of the use of Smart Box accompanied with OT Equator attachment in retaining the inclined implant assisted overdenture for atrophic maxilla. Materials and methods: Ten patients with posterior atrophic maxilla and partially dentate mandible with posterior occlusal stops were allocated for this study. For each patient, an implant assisted maxillary overdenture was fabricated using minimally invasive flapless surgical technique. Four implants were placed while the most anterior implants were axial and the most posterior implants divergent to 25 degrees using CAD/CAM surgical guide. The implants were loaded immediately by OT EQUATOR and smart box attachment retained maxillary overdenture. Each patient was evaluated clinically at the final prosthesis insertion (baseline), three, six and nine months post insertion. Modified gingival index (MGI), Clinical attachment Level (CAL) and Peri-implant probing depth (PIPD) are the clinical parameters that were evaluated. Results:MGI, CAL and PIPD revealed significant increase in both tilted and axial groups throughout the evaluation period intervals. Tilted implants group showed significantly greater increase in all parameters when compared with the axial group. Conclusions: Within the limitations of this study, it can be concluded that combination of axial and tilted implant assisted overdenture is a predictable treatment option in case of severely atrophic posterior maxillae.

INTRODUCTION: CAD/CAM denture base materials are milled from pre-polymerized pucks of resin that are highly condensed. So, they provide no polymerization shrinkage eliminating its subsequent disadvantages. This technology offered improved fit, strength properties and more bio-hygienic denture bases compared with conventional processing of the denture base material. OBJECTIVES: The aim of the study was to evaluate the physico-mechanical properties of CAD/CAM denture base material and the effect of thermo-cycling on it compared with the conventional one. MATERIALS AND METHODS: The study was conducted on two parallel groups, divided according to the denture material used. Group (1) conventional PMMA (control group), group (II) CAD/CAM PMMA (study group) of 40 specimens each (16 for impact strength, 16 for flexural strength, 8 for surface roughness and grinded powder form both materials for residual monomer test). Each group was divided into 2 sub-groups: (A) No thermo-cycling and (B) Thermo-cycling, then subjected to 4 different tests, impact strength, flexural strength, surface roughness and residual monomer tests. Data were collected, tabulated and statistically analyzed. Significance level was set at 5%. Bar charts were used for graphical presentations. RESULTS: Our study revealed a highly statistically significant decrease in residual monomer of CAD/CAM PMMA material in both conditions before and after thermo-cycling when compared to conventional PMMA material, which therefore leads to enhanced impact strength and significantly reduced surface roughness after heat treatment. On the other hand, also a highly significant reduction of its flexural strength after thermocycling has been observed. CONCLUSIONS: CAD/CAM dentures with lower amount of methacrylate monomer exhibit more favourable physico-mechanical properties and they have a long-term biocompatibility even with thermal changes making them a more satisfactory as a denture base material for edentulous patients.

The current paper explores the relation between managers’ risk attitude and cost stickiness behavior and the role of demand uncertainty as a moderation variable in the Egyptian business environment. Managers’ risk attitudes are measured using Bo and Sterken (2007) proxy measure [Bo, H., & Sterken, E. (2007). Attitude towards risk, uncertainty, and fixed investment. The North American Journal of Economics and Finance, 18(1), 59–75]. Demand uncertainty is measured by the standard deviation of firms’ sales over the sample period. The study sample includes 114 Egyptian-listed firms over a 14-year period (2004 - 2017) which results in 1,419 firm-year observations. The study models are estimated using the ordinary least squares (OLS) with a fixed-effects model. Findings show that in the presence of high demand uncertainty, risk-averse managers respond to sales decrease by cutting resources which lowers cost stickiness. One of the limitations is that some factors like firms’ policies, corporate governance mechanisms, and board of directors’ characteristics could dilute the effect of manager’s risk attitude on cost stickiness. The current research emphasizes the importance of considering the firm’s operating environment when selecting a manager for the firm, and the role of directed training to align the manager’s personal characteristics with the firm's objectives. The current research contributes to the previous literature by documenting the effect of manager’s risk attitude on cost stickiness and the role of a firm’s demand uncertainty as a moderating variable between these two variables.

Statement of the problem nbsp Designing of removable partial denture RPD present numerous biomechanical problems regarding the principles of reciprocation However extra coronal resilient attachment does not always supply suitable support and bracing because of their resilient nature Therefore they require specially designed bracing arms on surveyed crowns that require deeper tooth preparation lingually to prevent over contouring of the abutment teeth crown Purpose of the study The aim of this study was to evaluate clinically and radiographically the extra coronal semi precision attachments incorporated in metallic RPD with two different designs of reciprocation parallel interlock and integrated interlock Materials and methods nbsp Six patients were selected for this study having maxillary completely dentulous arch against mandibular bilateral distal extension ridges posterior to second premolar All attachment clinical and laboratory steps were performed for both designs using Split mouth experimental method Abutment teeth were examined clinically using Plaque Index Gingival Index Periodontal Probing Pocket Depth and Clinical Attachment Level and radiographically immediately at time of RPD insertion then months of denture use Results nbsp Clinical results showed statistically significant increase in all parameters around parallel interlock design than integrated interlock design after six months There was statistically significant increase in total mesial and distal bone loss associated with parallel interlock design in relation to integrated interlock design at six months follow up period Conclusions Absence of lingual bracing arm with integrated interlock design decreased the opportunity for plaque accumulation and enhanced the oral health of the premolar abutment teeth Clinical implications nbsp This study recommends the use of integrated interlock design for reciprocation as a common design of extracoronal semiprecision attachment for distal extension RPD for its favorable intraoral health parameters

1.Abstract 1.1.Background: One of the attachments used nowadays are the stud Positioner attachments, these attachments can be incorporated in the denture base of the implant assisted overdenture directly inside the patients mouth or indirectly in the laboratory. No studies evaluated the difference in denture-tissue relation in overdentures with attachments incorporation directly or indirectly. Therefore the aim of the present study was to evaluate whether a difference in denture-tissue relation exists between direct or indirect attachment incorporation. Two implants were placed for 7 patients and then an implant assisted overdenture was fabricated, first with indirect attachment incorporation, then with direct attachment incorporation. CBCT scans were performed on the patients with the overdentures in place after 1 week of denture insertion. The area of the mucosa between the fitting surface of the denture and the bone was measured as a guide for denture-tissue relation. 1.2.Results: The mean anterior mucosal surface area in dentures constructed using indirect attachment incorporation was 21.07mm2 ± 4.89 while the surface area at point M in dentures constructed by direct attachment incorporation was 20.53mm2 ± 5.14. While the mean posterior mucosal surface area in dentures constructed using indirect attachment incorporation was 35.88mm2 ± 3.98 while the mean posterior mucosal surface area in dentures constructed by direct attachment incorporation was 34.22mm2 ± 3.72. 1.3.Conclusion: Direct attachment incorporation causes greater posterior denture settling than indirect attachment incorporation.

Statement of problem: The improvement of the oral function of implant retained mandibular overdentures may depend on the degree of retention and stability of the denture and thus on the type of attachment. Purpose of the study: The aim of the study was to evaluate of the effect of two different attachment designs with different resiliency of implant retained mandibular overdentures on the masticatory function. Methods: Twelve completely edentulous patients were selected for the study each patient received two interforaminal implants in the canine areas of the mandible using standardized two-stage surgical technique. Implants were left unloaded for three months. Six of the patients received implant overdenture with ball and socket attachment first then the same denture was modified to receive positioner attachment. The other six patients received the implant overdenture with positioner first then the same denture was modified to receive ball and socket. Muscle activity and maximum muscle activity of both temporalis and masseter muscles were recorded during chewing cake, peanut and during clenching with using the electromyography. Results: Muscle activity and maximum muscle activity showed higher results with the positioner attachment in both masseter and temporalis muscles although the difference was not statistically significant. Masseter muscle showed higher results in both types of the attachments. Conclusion: The positioner attachment might be selected over Ball & Socket attachment when designing a two implant retained mandibular overdentures since it is more superior from the masticatory function point of view.

Statement of the problem: A key factor for the success or failure of dental implants is the manner in which stresses are transferred to surrounding bone. Purpose of the study: The aim of this study was to create complete three- dimensional finite element models of mandibles with their implant-retained over dentures (IRO) to evaluate the influence of two different attachment systems on stress distribution at implant bone level. Methods: The geometries of six edentulous mandibles with their IRO were generated from computed tomography scans. Two implants (3.75mm x 13mm) with ball abutments and locator attachments were placed in the canine areas of each edentulous mandible. Two models FEM (A) and FEM (B) were used for the load application and analysis. A vertical (100 N) and oblique (100 N) loads were applied to each of the above models respectively at the premolar/molar region of the over dentures. These two different models were analyzed by a finite element program (Solid Works) and displayed using Von misses stress patterns. Results: The results showed that the maximum stress values were seen at the crestal bone around all implants. Lower stress values were recorded for the locator attachment at all measured aspects. Vertical loading was associated with higher stress values and working side implants were showing greater stress magnitudes. Conclusion: Within the limitations of this study, locator attachment may be an adequate alternative to ball attachment as it reduces stresses on the implant body and supporting structures for implant-retained over dentures.

Aims: The purpose of this study was to evaluate the effect of bilateral balanced occlusion (BBO) and canine guidance occlusion (CGO) on the masseter muscle activity using implant-retained mandibular overdentures. Subjects and Methods: Cone beam computed tomography evaluation of twelve edentulous patients was completed. Mucoperiosteal flaps were reflected and two implants were placed in the interforaminal region for each of the twelve patients. After a healing period of 3 months, acrylic resin maxillary complete dentures and mandibular overdentures were fabricated with BBO for six patients and CGO for the other six patients. Positioner attachments were used. Electromyographic evaluation of the masseter muscles, during clenching on a silicon index and chewing peanuts and cake, was conducted on the patients after using their dentures for 4 weeks. Each occlusion concept was then converted into the other concept using the same dentures and the procedure of evaluation was repeated after 4 weeks. The recordings were analyzed statistically using Wilcoxon signed ranks test. The value of P Statistical Analysis Used: Kruskal–Wallis test and Mann–Whitney U-test were applied. Significance of the obtained results was judged at the 5% level. A P Results: The highest electromyographic activity of the masseter muscles was recorded during clenching on a preformed silicon index followed by chewing peanut then cake for both occlusal concepts. The recordings of the masseter muscle associated with CGO were higher than BBO but with no statistically significant difference. Conclusions: The results show that by applying CGO, muscle activities similar to bilaterally balanced occlusion were obtained.

Background The purpose of this prospective cross-over study is to evaluate the effect of bilateral balanced occlusion and canine guidance occlusion on the masseter muscle activity using implant-retained mandibular overdentures. Methods After evaluation of 12 completely edentulous patients using cone beam computed tomography (CBCT), mucoperiosteal flaps were reflected exposing the mandibular interforaminal region. Two implants were placed in the interforaminal region for each of the 12 patients. After a healing period of 3 months, acrylic maxillary complete dentures and mandibular overdentures were fabricated with bilateral balanced occlusion for 6 patients and canine guidance occlusion for the other 6 patients. Electromyographic evaluation of the masseter muscles, during clenching on a silicon index and chewing peanuts and cake, was conducted on the patients after using their dentures for 4 weeks. Each occlusion concept was then converted into the other concept using the same dentures, and the procedure of evaluation was repeated after 4 weeks. The recordings were analyzed statistically using Wilcoxon signed ranks test. p