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Purpose: The goal of the current study is to evaluate the stress distribution when tilted implants and mini-implants are used to support a mandibular overdenture. Materials and methods: Three-dimensional (3D) finite element models of mandibular overdentures were established using four, axial, standard-sized implants (SA model), four standard-sized implants with the mesial ones axial and the distal ones tilted (ST model) and four mini-implants (MA model) with Locator attachments. On each model, a 100 N load was applied to the overdenture in four different directions; bilateral vertical, unilateral vertical and oblique load on the posterior region, and a vertical load on the incisors. The stresses distributed at the peri-implant bone, implants, the prosthetic components, and the overdentures were evaluated. Results: Non-axial posterior loading caused higher stress values in the implant and the prosthetic component than axial posterior loading. Lower stress values of the implant and the prosthetic component were observed in the ST model than SA model. The stress distribution in the overdenture at posterior loads were mostly observed around the implants. Conclusion: Less prosthetic complications may be expected when the treatment option in the ST model is used. Fatigue fractures may occur around the implants in the overdentures, precautions are advised.

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Background: Coaxial implants with an inclined neck might overcome some problems related to angulation of the implant axis when using tilted implants. Therefore, the aim of the present work was to conduct a narrative review of the current literature and to present a case series comparing traditional and coaxial external hex implants in full-arch immediate loading rehabilitations of the maxilla. Methods: A total of 13 external hex tapered implants (Southern Implants) was inserted in the upper jaw of 3 patients. Each patient received two tilted implants in distal sites. In one randomly selected quadrant, the tilted implant was a standard implant, while a Co-Axis® implant with a 24° inclination of the implant shoulder was inserted on the other hemi-arch. Straight conical abutments were screwed on coaxial implants while multiunit abutments of appropriate inclination were screwed as needed on the other implants to correct their axes. Peri-implant bone level was recorded radiographically at T0 (delivery of the immediate loading prosthesis), and at 3, 6, 12, and 24 months of healing and then annually. Plaque index, probing depth, and bleeding on probing were also evaluated. Cumulative implant survival rate (CSR) was calculated, and biological or technical complications were recorded as well as the operator satisfaction towards the use of coaxial implants. Results: The preliminary data collected did not show significant differences in peri-implant tissues health and maintenance over time between the two implant types. No implants failed, and both implant types proved to be favorable for full-arch rehabilitation using tilted implants. Coaxial implants facilitated the prosthodontic procedures. However, a learning curve is required in order to optimize their insertion. Conclusions: Both implants proved to be reliable and suitable for achieving clinical success in full-arch immediate loading rehabilitations, but further research with longer follow-up and larger sample size is needed to confirm these preliminary outcomes.

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OBJECTIVES: Does the angulation of ultrashort implants influence the stability of the peri-implant bone? The present study aimed to evaluate the effectiveness of non-axial ultrashort implants after 2 to 9 years of follow-up in resorbed alveolar ridges. MATERIALS AND METHODS: All partially edentulous patients with ultrashort implants (< 6 mm) used in the posterior region of an atrophic mandible or maxilla, to support partial dentures in conjunction with standard implants, were included in this study. Peri-implant bone loss, success and survival rates, crestal bone levels, crown-to-implant ratio and implant angulation were measured for each implant. Implants were divided into two groups: straight implants with angulation < 17° (control group) and tilted implants with angulation > 17° (test group). Statistical analysis was used to find any significant differences between the two study groups and to investigate significant linear correlations among all the variables (p = 0.05). RESULTS: A total of 42 ultrashort implants with a mean of 4 years of follow-up were included: 20 ultrashort axially loaded implants and 22 tilted implants. Mean crestal bone levels from baseline loading to maximum follow-up did not reveal statistical differences in regard to PBL; mean success and survival rates were 100% in all groups. CONCLUSIONS: PBL, success and survival rates of axial ultrashort implants and tilted ultrashort implants are comparable to those of conventional implants. CLINICAL RELEVANCE: This retrospective study revealed that ultrashort implants, even when placed with an angulation > 17°, can safely be used to support partial fixed prostheses. Further prospective clinical studies with larger samples and prospective design are needed to confirm these findings.

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Computer-assisted implant planning has become a key diagnostic and therapeutic tool in modern dentistry. This case report emphasizes the possibilities in modern implantology combining virtual implant planning, guided surgery with surgical templates, and immediate function. A 75-year-old female presented with maxillary and mandibular dentures and wanted fixed replacement in minimal appointments. Diagnosis, decision-making, and treatment approaches were based on clinical findings and detailed virtual three-dimensional implant planning. Guided implant placement of six implants in each arch using Tall and Tilted Pin Hole Immediate Loading Technique (TTPHIL ALL TILT®), and immediate loading with a provisional fixed dental prosthesis (FDP) was performed fulfilling patient's functional and esthetic demands in a minimally invasive manner. The final computer-assisted design/computer-assisted manufacturing (CAD/CAM) FDP with a titanium framework and ceramic layering was delivered after six months. At the three-year recall, the implant-supported FDP was free of any complications. Uneventful osseointegration of the dental implants and a healthy peri-implant mucosa were observed. Computer-assisted TTPHIL ALL TILT® technique including three-dimensional virtual implant planning, guided surgery, and CAD/CAM fabrication of provisional and final reconstructions allowed for a concise treatment workflow with favorable esthetic and functional outcomes in this maxillary and mandibular full-mouth case without the need of multiple surgeries in a short treatment time.

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Aim This study's objective was to assess and analyze, using 3D Finite Element Analysis, the impact of four mandibular complete arch superstructures on the distribution of stress in the crestal bone during mandibular flexure. Materials and methods Four Finite element models of the mandible with different implant-retained framework designs have been developed. Three of these models had six axial implants placed at intervals of 11.8 mm, 18.8 mm and 25.8 mm from the midline, respectively. One model had two tilted implants and four axial implants splinted with a single piece of framework at intervals of 8.4 mm, 13.4 mm and 18.4 mm from the midline. For analyzing the stress distribution, the finished product was transferred to ANSYS R 18.1 software (Sirsa, Haryana, India) for finite element simulation, the models were constructed, the ends were restrained, and bilateral vertical loads of 50N, 100N and 150N were applied to the distal part of the framework. Results Bilateral loads were applied to each of the four 3D FEM and after assessment of Von Mises Stress and Total Deformation, a finding was made that the model with six axial implants supported by a single piece of framework underwent the highest total deformation and the model with four axial implants and two implants with distal tilts displayed most significant Von Mises stress. Conclusion Within the constraints of this 3D FEA, it was determined that mandibular flexure and peri-implant bone stress were affected by the way the framework is divided and the nature of mandibular movement. The three types of frames with the least bone stress are demonstrated by the mandibular deformation that results from two-piece frameworks on axial implants. Regardless of the number of implants, the single framework splinted with six implants shows a flexure in mandible with the highest bone stress around the implant irrespective of the angulation of the implant. Clinical significance When it comes to edentulous jaws, reducing stress in implant-supported restorative systems at varying degrees of the bone and implant interfaces and superstructures of prosthetics is one of the fundamental goals of implant treatment. A framework with proper design and a low modulus of elasticity reduces mechanical risk. Additionally, a larger number of implants helps to prevent cantilevers and spacing between the implants.

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Purpose: The current study intended to provide a comparison of biomechanical behaviors of two different treatment concepts for full-mouth rehabilitation with dental implants placed according to the "All-on-four" concept and "All-on-six" concept with analysis of the stress patterns of the implant support system using three-dimensional finite element analysis (FEA). Materials and Methods: The edentulous mandible was treated with two different implant designs. "All-on-Four" implant placement concept was used in Model 1 with two central axial implants and two distally tilted implants at 17° and in Model 2, "All-on-Six" concept was applied with six vertically placed implants. Individual vertical and horizontal load of 100 N and oblique load of 141 N at 45° was applied to all implants. To evaluate and compare the results in terms of maximum principal stress, we used FEA. Results: All-on-six showed smaller maximum principal stress values on the cortical bone and implants. However, maximum principal stress values obtained on trabecular bone was smaller in the All-on-four design for vertical and horizontal loading conditions. Conclusions: The All-on-six approach showed more favorable biomechanical behavior.

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PURPOSE: To retrospectively assess clinical and radiographic outcomes of immediately loaded full-arch fixed prostheses supported by axial and tilted implants up to 15 years of function. MATERIALS AND METHODS: Patients with one completely edentulous arch received an immediate full-arch fixed prosthesis supported by two anterior axial and two posterior tilted implants. Definitive prosthesis consisting of a CAD-CAM titanium framework and acrylic teeth was delivered 6 months later. Patients were regularly followed to assess clinical parameters and marginal bone level (MBL) change. Multilevel regression analysis was performed to investigate factors affecting implant failure and MBL. RESULTS: Six hundred ninety-two implants were placed in 72 maxillae and 101 mandibles. Seven maxillary implants (5 axial and 2 tilted) in 6 patients and 12 mandibular implants (6 axial and 6 tilted) in 5 patients failed. 15-year cumulative implant survival was 97.51% and 96.91% in maxilla and mandible, respectively (p = .64). After 10 years, the difference in MBL between axial and tilted implants was not significant in the maxilla (p = .47, 65 patients), while it was in the mandible (p < .001, 80 patients). Significant higher bone loss was reported in the mandible at both 5- and 10-year follow-up (p < .001 and p = .004, respectively). Mixed-effect multilevel linear regression evidenced a correlation between arch and bone loss at 5- and 10-year follow-up, while no correlation was found with age, gender, smoking, diabetes, and history of periodontal disease. CONCLUSION: This long-term study suggests that the present technique can be considered a viable treatment modality for the immediate rehabilitation of both maxilla and mandible.

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BACKGROUND: Many clinical studies have reported the high success rate of the All-on-4 concept. In the present study, we aimed to compare the stress distribution with different tilted distal implants and cantilever lengths in an All-on-4 system using the two-dimensional photoelastic method and to establish the All-on-4 implant photoelastic model by computer-aided design (CAD) and rapid prototyping (RP).  METHODS: The data of the human edentulous mandible were acquired by computed tomography (CT). Three human edentulous mandible All-on-4 implant models with different distally inclined implant holes were fabricated using Mimic, Geomagic Studio software, and a light solidifying fast shaping machine. Then the final photoelastic models were established through the traditional method. Each of the three models had four NobelSpeedy Replace implants between the interforaminal regions. The two posterior implants were placed 0, 15, and 45 degrees distally before the mental foramen. The four implants were splinted by wrought cobalt-chromium alloy frameworks. Each of the three photoelastic models was submitted to a 150 N vertical load at five points on the framework: the central fossa of the mandibular first molar, and 0 mm, 5 mm, 10 mm, and 15 mm of the cantilever length. The stress produced in the models was photographed with a digital camera, and the highest value of the stressed fringe pattern was recorded. RESULTS: The All-on-4 implant photoelastic model established by CAD and RP was highly controllable and easy to modify. The position and inclination of implants were accurate, and the frameworks could be passively emplaced. The stress values were higher around a single tilted implant compared with the distal implant in All-on-4 with the same inclination. The 0-degree distal implant and 45-degree distal implant demonstrated the highest and lowest stress when loading at the central fossa of the mandibular first molar, respectively. With the same inclination of distal implant, the peri-implant bone stress increased as the length of cantilever increased. CONCLUSION: The method of establishing the All-on-4 implant photoelastic model by CAD and RP was highly controllable, convenient, fast, and accurate. The tilted implants splinted in the fully fixed prosthesis with reduced cantilever lengths did not increase the stress level compared with the vertical distal implants.And this illustrated that the influence of cantilever on stress distribution was greater than the influence of implant inlination.

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OBJECTIVES: to retrospectively evaluate clinical and radiographic outcomes of immediate, flapless full-arch prostheses, supported by 4/6 implants according to prosthetic-driven planning and guided surgery. MATERIALS AND METHODS: The study involved 28 edentulous patients (20 female/8 males; average age 67.75 ± 8.627 years), 32 prostheses (17 all-on-4/15 all-on-6) and 164 implants. The Implants survival, prostheses success/survival, peri-implant marginal bone loss, incidence of biological and prosthetic complications were evaluated. Multiple linear regression analysis was performed to analyze the influence of implant and patient characteristics on marginal bone loss. RESULTS: Cumulative implant survival rate was 89.7% for all-on-four (seven failures) and 99.0% for all-on-six (one failure) after a mean follow-up of 6.46 ± 2.236 years (range 1-10 years). Cumulative prosthesis success rate was 51.5% (58.8% for all-on-four/ 43.8% for all-on-six). Prosthesis survival rate was 88.2% for all-on-four. No failure was registered in all-on-six. Mean value of marginal bone loss was 1.38 ± 0.1.28 mm at 5-year and 2.09 ± 0.56 mm at 10-year follow-up. No difference was found in the mean value of marginal bone resorption between all-on-four (1.56 ± 1.61 mm) and all-on-six (1.20 ± 0.85 mm) (p = 0.104) and between tilted (1.22 ± 1.29 mm) and axial implants (1.44 ± 1.27 mm) (p = 0.385) after 5-year follow-up. The incidence of biological complications was 1.0% in all-on-six (one mucositis) and 10.3% in all-on-four (two peri-implantitis). Prosthetic complications affected teeth of final rehabilitations with 3 detachments, 10 chippings or fractures, and 3 severe occlusal wears. CONCLUSIONS: Based on the results and within the limitations of the present study, the implant-supported hybrid prosthesis according to prosthetic-driven planning and guided surgery showed to be an efficient, safe, and effective approach to rehabilitate edentulous jaws.

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This study's purpose is to assess the stress distribution in the peri-implant bone, implants, and prosthetic framework using two different posterior implant angles. All-on-four maxillary prostheses fabricated from feldspathic-ceramic-veneered zirconia-reinforced lithium silicate (ZLS) and feldspathic-ceramic-veneered cobalt-chromium (CoCr) were designed with 17 or 30-degree-angled posterior implants. Posterior cantilever and frontal vertical loads were applied to all models. The distribution of maximum and minimum principal stresses (σmax and σmin) and von Mises stress (σVM) was evaluated. Under posterior cantilever load, with an increase in posterior implant angle, σmax decreased by 4 and 7 MPa in the cortical bone when ZLS and CoCr were used as a prosthetic framework, respectively. Regardless of the framework material, 17-degree-angled posterior implants showed the highest σVM (541.36 MPa under posterior cantilever load; 110.79 MPa under frontal vertical load) values. Regardless of the posterior implant angle, ZLS framework showed the highest σVM (91.59 MPa under posterior cantilever load; 218.99 MPa under frontal vertical load) values. Increasing implant angle from 17 to 30° caused a decrease in σmax values in the cortical bone. Designs with 30-degree posterior implant angles and ZLS framework material may be preferred in All-on-four implant-supported fixed complete dentures.

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The aim of the present study is to assess by means of finite element models the effect on bone stresses of implant length and tilting in single-unit implant restorations. The factors that were analyzed in this study were implant length (4.5, 5.5, and 10 mm), implant titling (0, 17°, 30°, and 45°), bone type (0/I, II, and III), and loading (immediate and delayed). An axial load of 200 N was applied to the occlusal surface of the prosthesis at a height of 11 mm and the Von Mises equivalent stress in the bone was analyzed. Finite element analysis indicated that the most determinant factor was implant tilting. Tilting the implant by 17° doubled the Von Mises stress received by bone. The highest increase was in the case of implant tilting at 45° (by 1300%). The use of extra-short implants did not produce a significant increase in Von Mises stress in bone. Moreover, the length of the implant did not affect the stress value in bone types I and II. Based on the obtained results, an axially placed short implant would be a better option than titling a standard-length implant to support a crown restoration in an atrophic mandible from a biomechanical point of view.

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BACKGROUND: Zygomatic implants (ZIs) that are anchored in remote locations can significantly improve the retention and stability of prosthetic obturation in maxillary defect sites without the need for complex surgical reconstruction. However, ZI placement without alveolar bone guidance is challenging, especially when identifying the ideal three-dimensional location of the "coronal part" of the implant fixture for further rehabilitation. PURPOSE: To investigate the feasibility and accuracy of surgical navigation for ZI placement using prosthetically driven plans to treat extensive maxillary defects. MATERIAL AND METHODS: Software was used to virtually plan the number and distribution of ZIs for maxillary defect patients according to the existing residual maxillofacial bone. The "coronal part" of the ZI was identified based on the existing maxillodental prosthetic flange, virtually planned infrastructure framework and superstructure. ZI placement was fully guided by surgical navigation. RESULTS: Ten patients were enrolled. One patient had loose reflective spheres, which resulted in an inaccurate back-reflection of the position during navigation. A total of 27 ZIs in the remaining 9 patients were placed uneventfully. The mean of the "coronal part" of the ZI, entry point of the zygomatic bone, apical deviation, and apical angle deviation were 1.50 mm, 1.39 mm, 1.95 mm, and 2.32°, respectively. A Computer-aided design and computer-aided manufacture milled bar and additional attachments were fabricated according to preoperative planning. No osseointegrated implant loss was detected. Six ZIs in three patients received implant surface polishing to reduce soft tissue irritation, and one ZI was submerged. DISCUSSION: Surgical navigation facilitated the accurate and feasible placement of prosthetically driven ZIs that were preoperatively planned in patients with extensive maxillary defects.

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BACKGROUND: All-on-four protocols with tilted implants in the maxilla are used to rehabilitate the terminal dentition of the severe generalized periodontitis patients. Data on long-term biological complications are scarce. METHODS: Eighty-four axial and forty-six tilted immediate implants have been placed in the extraction sockets of 23 patients according to a four-six implants protocol combined with ridge augmentation. Within 72 h, a provisional prosthesis was cemented to the implants; after 6 months, a cemented ceramic-metallic prosthesis was delivered. The patients were followed for up to 5 years. RESULTS: The 5-year survival rate of the straight and tilted implants was 100% and 97.8, and the prosthetic one was 100%. Marginal bone loss (MBL) of the straight implants was 0.42 ± 0.67 and 0.59 ±1.01 mm on the mesial and distal sides; for the tilted, it was 0.37 ± 0.68 and 0.34 ±0.62 mm, and the differences were not statistically significant. Implant position, smoking, keratinized mucosal width, and cantilever did not affect MBL. Peri-implant mucositis involved 29.4% and 22.2% of the straight and tilted implants, respectively; peri-implantitis involved 5.8% and 4.4% of the straight and tilted implants, respectively, without statistical significance. CONCLUSIONS: This immediate loading protocol's 5-year survival and success rates were high. No difference between the straight and tilted implants was found regarding survival, success rates, and MBL.

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OBJECTIVE: Address oral health-related quality of life (OHRQoL) and patient satisfaction rehabilitated by the all-on-four concept as the primary outcome. MATERIAL AND METHODS: A search was performed in the PubMed/MEDLINE, Web of Science, and Cochrane databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis criteria (PRISMA). The PICO question was used to address the following specific question: "What is the level of oral health-related quality of life and satisfaction in edentulous patients and with atrophic jaws who received dental implants for full-arch implant-supported restorations following the all-on-four in the mandible or maxilla?" RESULTS: Eleven studies including 693 patients aged 55 to 71 years were selected. The shortest follow-up period was 3 months and the longest, 7 years. Regarding the OHRQoL assessment method and patient satisfaction, the oral health impact profile (OHIP) and the visual analog scale (VAS) were the most used. CONCLUSION: OHRQoL and satisfaction in patients whose rehabilitation was based on the all-on-four concept were high. However, the current evidence is still limited by the quality of the available studies, making long-term randomized studies necessary to establish the real effectiveness of this surgical-prosthetic approach. CLINICAL RELEVANCE: Carefully analyze the aspects related to satisfaction and oral health-related quality of life of rehabilitated patients with implant-supported total prostheses made according to the all-on-four concept, aiming to achieve success through procedures with greater predictability and less complexity, as these are directly associated with recovery oral health of edentulous individuals with less morbidity and minimized costs.

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OBJECTIVES: This study aimed to determine whether distally angulating an implant is a successful strategy to avoid the maxillary sinus and the need for bone augmentation, while increasing the anterior-posterior (A-P) implant distribution in the edentulous maxilla. MATERIALS AND METHODS: In 115 patients with edentulous maxillae, virtual implant planning was performed utilizing cone-beam computer tomographs. Axial (8 mm length) and tilted (12 mm length) dental implants with 30-degree and 45-degree angulation were virtually positioned to avoid entering the maxillary sinus, while maximizing A-P distribution. Measurements were made between the tilted and axial implants to assess the change in A-P distribution of implants at the implant and abutment levels. RESULTS: Forty-seven sites (20.4%) were not able to have either treatment modality with insufficient bone for implant placement. Axial implants were placed more distally than 45-degree and 30-degree tilted implants in 24% and 42% of sites, respectively. The average change in A-P spread measured at the implant level, for 30- and 45-degree tilted implants was -0.25 mm (95% CI -0.76, 0.26) and 1.9 mm (95% CI 1.4, 2.3), respectively. When measured from the center of each multi-unit abutment the average increase in A-P distances for tilted implants appears larger in the 30-degree and 45-degree groups by 0.97 mm and 1.74 mm, respectively compared to measurements at the implant level. CONCLUSIONS: Angulating 12 mm implants provides a limited increase in A-P distribution of implants in edentulous rehabilitation in most situations. In certain patients, the use of 8mm axial implants may provide a greater A-P spread.

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Aim: This systematic review and meta-analysis evaluated the clinical survival of axial and tilted implants in atrophic edentulous maxilla after three years of immediate loading and also the corresponding marginal bone loss. Setting and Design: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (PRISMA). Materials and Methods: The relevant studies were retrieved from MEDLINE(PubMed), the Cochrane Central Register of Controlled Trials (CENTRAL), Science Direct, Google Scholar databases. The search was limited to studies published in the English language with no date restrictions. A further hand search was conducted on individual journals and reference lists of studies. The risk of bias in included studies was assessed by using the Evidence Project risk of bias tool. Statistical Analysis Used: Statistical meta-analysis was conducted using RevMan 5.4 software. The assessment for the level of evidence was done using GRADEpro software. Results: Eleven studies were finalised. All were included in the meta-analysis for implant survival, while only seven studies were included in the meta-analysis of marginal bone loss. After three years, the meta-analysis results for implant survival showed no statistical difference between axial and tilted implants, with the forest plot neither favouring axial nor tilted implants (RR = 1.00 (95% CI: 0.98-1.01); P-value = 0.59). After three years, the meta-analysis results for marginal bone showed no statistical difference between axial and tilted implants, with the forest plot neither favouring axial nor tilted implants (MD = -0.02; 95% CI; -0.09-0.06; P-value = 0.69). Conclusion: In the immediately loaded rehabilitation of completely edentulous atrophic maxillae, tilting of implants did not induce any significant alteration in their survival and their corresponding marginal bone loss levels compared to conventionally placed axial implants even after three years of function.

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This study aimed to investigate the effects of the different dental implant neck designs, diameters, and inclinations, on the stress distributions at the mandibular crestal bone and implant-abutment complex, using three-dimensional (3D) finite element stress analysis (FEA) method. Finite element models of three-unit fixed partial dentures supported with two same length implants (10 mm), placed on the second premolar and second molar regions, were designed. Eight different models were designed according to the implants' neck designs (platform switching/traditional), diameters (4.1 mm/4.8 mm) and the tilting angles of the posterior implants (0°/15°). The anterior implants' widths were 4.1 mm and the neck design of the anterior implants matched the posterior implants. Two types of 100-N loads in vertical and 30° oblique directions were applied separately onto each central fossae and functional cusps of the fixed partial dentures crowns. Algor Fempro Software was used for the simulation and evaluation of the stress levels at the implant-abutment complex and the crestal bone. Stress levels measured at the crestal bone were found to be lower for the platform switching models. However, the platform switching design generated higher stress magnitudes within the implant-abutment complex. Inclined placement of posterior implants increased the amount of stress at the crestal bone around both implants. Biomechanically, selection of the largest diameter possible when using tilted platform switched implants may be recommended at the posterior mandible.

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Aim: The aim of this review was to evaluate the survival rate of axial and tilted implants in rehabilitation of edentulous jaws using all on four concept. Setting and Design: Systematic Review. Materials and Methods: A literature review was performed in MEDLINE, PubMed Central (PMC), Google scholar, Embase, Cochrane Central Register of Controlled Trials. Hand searches were conducted of the bibliographic of related journals and systematic reviews. A total of 380 articles were obtained from the intial screening process. Of these articles, 25 articles fulfilled the inclusion criteria. The authors performed evaluation of articles independently as well as data extraction and quality assessment. Statistical Analysis Used: Qualitative analysis. Results: The major prosthetic complication was the fracture of the acrylic prosthesis. The mean cumulative survival rate of implants (72-132 months) were 94% to 98%. The prosthesis survival rate (12 months) was between 99% to 100%. The averaged bone loss was 1.3 ±0.4 mm (12-60 months). No Significant difference was found between survival rates of axial and tilted implants nor between maxilla and mandible. Conclusion: All on four concept can be employed successfully in the edentulous patients with resorbed ridges while improving their quality of life and reducing morbidity. However,randomized clinical trials with large sampling size and long term follow up should be incorporated.

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OBJECTIVES: The purpose of this study was to evaluate crestal bone stability around sloped implants using the flapless procedure and compare it with conventional implants placed axially. MATERIALS AND METHODS: A total of 40 bone-level implants with platform switching were used for this study for 10 patients (4 males and 6 females) in edentulous mandible. Twenty mesial conventional implants were placed in upright position and 20 distal 30° sloped implants tilted 30°. Bone loss was estimated using radiographic imaging after a 6- and a 12-month follow-up period. Comparison of the bone loss in the distal and mesial region at both implantation angles were conducted to understand the nature and progression of crestal bone loss. RESULTS: Crestal bone loss around the sloped implants was 0.29 mm (SD = 0.292) on average, while around conventional implants it was 0.22 mm (SD = 0.202) after one-year follow-up. However, there was no significant difference in the average of crestal bone loss between two trial groups after 6 months (p < 0.243) and one-year (p < 0.614) follow-up. The results indicated a 100% implant survival rate after one-year follow-up. Additionally, three fixed prostheses needed realignment after fracturing during the follow-up time. CONCLUSION: Considering the limitations of this study, it can be presumed that sloped and conventional implants with platform switching and conical connection have the same potential for minimal crestal bone loss.

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Over the past 17 years, the All-on-4 treatment concept has been a reliable and predictable modality to rehabilitate edentulous jaws with immediate function as full-arch prostheses. This article highlights clinically relevant data compiled by numerous All-on-4 investigators including complications and their remedies, occlusion and cantilever trends, implant size utilization, and controversial topics. We provide insights for navigating the complexities of medically diverse populations, faced by our daily practice, with a focus on patient avoidance, risk factors for implant and prosthetic failures, in hopes to minimize complications so clinicians would choose this treatment with confidence.

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