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Purpose: The purpose of this 3D finite element analysis was to evaluate the biomechanical effects of different materials used to fabricate occlusal devices to achieve stress distribution in simulated abutment screws, dental implants, and peri-implant bone tissue in individuals who clench their teeth., Materials and Methods: Eight 3D models simulated a posterior maxillary bone block with three external hexagon implants (Ø4.0 × 7.0 mm) supporting a 3-unit screw-retained metal-ceramic prosthesis with different crown connection (splinting), and the use of an occlusal device (OD). The OD was modeled to be 2-mm thick. ANSYS 19.2 software was used to generate the finite-element models in the pre-and post-processing phases. Simulated abutment screws and dental implants were evaluated by von Mises stress maps, and simulated bone was evaluated by maximum principal stress and microstrain maps by using a finite element software program., Results: The highest stress values in the dental implants and screws were observed in single crowns without OD (M1). Furthermore, the highest stress values and bone tissue strain were found in single crowns without OD (M1). The simulated material for the OD did not cause many discrepancies in terms of the stress magnitude in the simulated dental implant and abutment screw for both single and splinted crowns; however, more rigid materials exhibited lower stress values., Conclusion: The use of OD was effective in reducing stress in the simulated implants and abutment screws and stress and strain in the simulated bone tissue. The material used to simulate the OD influenced the biomechanical behavior of implant-supported fixed prostheses, whereas splints with rigid materials such as PEEK and PMMA exhibited better biomechanical behavior., (© 2023 by the American College of Prosthodontists.)

Purpose: To evaluate the tendency of movement, stress distribution, and microstrain of single-unit crowns in simulated cortical and trabecular bone, implants, and prosthetic components of narrow-diameter implants with different lengths placed at the crestal and subcrestal levels in the maxillary anterior region using 3D finite element analysis (FEA)., Materials and Methods: Six 3D models were simulated using Invesalius 3.0, Rhinoceros 4.0, and SolidWorks software. Each model simulated the right anterior maxillary region including a Morse taper implant of Ø2.9 mm with different lengths (7, 10, and 13 mm) placed at the crestal and subcrestal level and supporting a cement-retained monolithic single crown in the area of tooth 12. The FEA was performed using ANSYS 19.2. The simulated applied force was 178 N at 0°, 30°, and 60°. The results were analyzed using maps of displacement, von Mises (vM) stress, maximum principal stress, and microstrain., Results: Models with implants at the subcrestal level showed greater displacement. vM stress increased in the implant and prosthetic components when implants were placed at the subcrestal level compared with the crestal level; the length of the implants had a low influence on the stress distribution. Higher stress and strain concentrations were observed in the cortical bone of the subcrestal placement, independent of implant length. Non-axial loading influenced the increased stress and strain in all the evaluated structures., Conclusions: Narrow-diameter implants positioned at the crestal level showed a more favorable biomechanical behavior for simulated cortical bone, implants, and prosthetic components. Implant length had a smaller influence on stress or strain distribution than the other variables., (© 2023 by the American College of Prosthodontists.)

Purpose: To assess the effects of tilted external hexagon implants and splinted restorations in terms of stress distribution on the bone tissue, implants, and prosthetic screws, using three-dimensional finite element analysis., Materials and Methods: Six models were used to simulate a posterior maxilla bone block (type IV) from the first premolar to the first molar. Each model included three 4.1-mm-diameter external hexagon implants with varying inclinations (0°, 17°, and 30°) and crown designs (splinted and nonsplinted restorations). The forces applied were as follows: 400 N axially (50 N for each slope of the cusp) and 200 N obliquely (45° only on the buccal slope of the cusp). Stress distribution on the implants and prosthetic screw was evaluated using Von Mises stress, while the maximum principal stress was used to evaluate the stress distribution in the bone tissue., Results: The oblique load increased the stress on all the structures in all the models. Increased inclination of the implants resulted in higher stress concentration in the bone tissue, implants, and prosthetic screws. However, splinted restorations contributed to reduction of the stress for the oblique loading, mainly in the bone tissue and prosthetic screw of the first molar, as the stress was shared between the first and second premolar restorations., Conclusions: Tilted implants increased proportionally the stress on bone tissue and prosthetic screws of models. Additionally, splinting restorations reduced the stress concentration area in the simulated bone tissue, implants, and prosthetic screws in the first molar, as the stress was shared with the adjacent implants., (© 2021 by the American College of Prosthodontists.)

This is an in silico study aimed to evaluate the biomechanical influence of different implant-abutment interfaces (external hexagon and Morse taper implants), retention systems (cement and screw retained), and restorative crowns (metal-ceramic and monolithic) using 3-dimensional finite element analysis (3D-FEA). Eight 3D models were simulated for the maxillary first molar area using InVesalius, Rhinoceros, and SolidWorks and processed using Femap and NEi Nastran software. Axial and oblique forces of 200 and 100 N, respectively, were applied on the occlusal surface of the prostheses. Microstrain and von Mises stress maps were used to evaluate the deformation (cortical bone tissue) and stress (implants/fixation screws/crowns), respectively, for each model. For both loadings, Morse taper implants had lower microstrain values than the external hexagon implants. The retention system did not affect microstrain on the cortical bone tissue under both loadings. However, the cemented prosthesis displayed higher stress with the fixation screw than the external hexagon implants. No difference was observed between the metal-ceramic and zirconia monolithic crowns in terms of microstrain and stress distribution on the cortical bone, implants, or components. Morse taper implants can be considered as a good alternative for dental implant rehabilitation because they demonstrated better biomechanical behavior for the bone and fixation screw as compared to external hexagon implants. Cement-retained prosthesis increased the stress on the fixation screw of the external hexagon implants, thereby increasing the risk of screw loosening/fracture in the posterior maxillary area. The use of metal-ceramic or monolithic crowns did not affect the biomechanical behavior of the evaluated structures.

Statement of Problem: Whether providing an occlusal device for a patient with bruxism and an implant-supported fixed dental prosthesis leads to improved biomechanics is unclear., Purpose: The purpose of this 3D finite element analysis (FEA) study was to evaluate the biomechanical behavior of 3-unit implant-supported prostheses under parafunctional forces with and without an occlusal device., Materials and Methods: Eight 3D models consisting of a posterior (type IV) maxillary bone block with 3 external hexagon implants (Ø4.0×7.0 mm) and 3-unit implant-supported prostheses with different crown connections (splinted or unsplinted) and an occlusal device under functional and parafunctional loading were simulated. The abutment screws were evaluated by von Mises stress maps, and the bone tissue by maximum principal stress and microstrain maps by using a finite element software program., Results: An occlusal device improved the biomechanical behavior of the prostheses by reducing stress in the abutment screws and stress and strain in the bone tissue. However, the use of an occlusal device was not sufficiently effective to negate the biomechanical benefit of splinting., Conclusions: The use of splinted crowns in the posterior maxillary region with an occlusal device was the most effective method of reducing stress in the abutment screws and stress and strain in the bone tissue when parafunction was modeled., (Copyright © 2021 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Background: This photoelastic analysis evaluated stress distribution in different osteosynthesis systems, conventional and locking, used for treatment of mandibular angle fractures with a single plate., Material and Methods: Angle fractures were simulated in mandibles made of photoelastic resin. Following Champy's method, plate osteosynthesis was performed. The samples were divided into five groups: Group 1, non-fractured mandible; Group 2, two screws were installed in each segment using a conventional system; Group 3, two screws were installed in each segment using a locking system; Group 4, three screws were installed in the proximal segment and four screws in the distal segment using a conventional plate; Group 5, three screws were installed in the proximal segment and four screws in the distal segment using a locking plate. In an universal testing machine coupled to a polariscope, a load was applied to the first molar 10 times. The 50 images were randomly numbered and analyzed qualitatively and quantitatively by two raters., Results: The locking system promoted better stress distribution along the osteosynthesis. The locking system reduced stress magnitude in the distal segment, with a significant between-group difference ( P ≤ 0.001)., Conclusions: The locking plate/screw system can distribute stress more evenly throughout the osteosynthesis, especially when long seven-hole plates are used. Key words: Internal fracture fixation, osteosynthesis, mandibular fracture, bone plates., Competing Interests: Conflicts of interest The authors have no conflicts of interest to disclose., (Copyright: © 2021 Medicina Oral S.L.)

The oral cavity is an environment that allows for the development of complex ecosystems; the placement of prosthetic devices as a consequence of partial or total tooth loss may alter the diversity of microbial communities. Biofilms on the surface of materials used in dental prostheses can promote important changes in the mechanic and aesthetic properties of the material itself and may cause local and systemic diseases for the prosthetic wearer. This review presents the main features of the oral microbiome associated with complete or partial dentures and dental implants. The main diseases associated with microbial colonization of prosthetic surfaces, factors that may affect biofilm formation on prosthetic materials, as well as novel alternative therapies aiming to reduce biofilm formation and/or to eradicate biofilms formed on these materials are also explored.

This study aimed to assess the effects of splinting in 3-unit implant-supported prostheses with varying the splinting factor, length of the implant, and the diameter of the 1°molar (1°M) implant on cortical bone tissue (CBT). Twelve 3D models were simulated, which represented the posterior maxillary with 3 implants, supporting 3-unit FDP varying the splinting factor (single-unit crowns, splinted crowns straight-line and offset implant configuration [OIC]), length of the implant (7mm and 8,5mm), and the diameter of the 1°M (Ø4 mm and Ø5 mm). The CBT was analyzed by maximum principal stress and microstrain maps. The increase in implant diameter improved the biomechanical behavior of rehabilitation. The increase of the implant diameter in the 1°M associated with OIC generated the best biomechanical behavior for CBT. The splinting was effective in decreasing stress and microstrain, mainly when associated with OIC and implant diameter of Ø5 in the 1°M. The effect of increasing the diameter of the implant referring to the 1°M for single-unit crowns was more effective than the effect of the splinting of implants with Ø4 mm in straight-line. The diameter and splinting factors showed to be more important than implant length to reduce the stress and microstrain on CBT., (Copyright© 2021 Dennis Barber Ltd.)

Purpose: To evaluate implant and prosthetic survival rates of full-arch rehabilitations retained by three implants in patients with edentulous mandibles., Materials and Methods: This systematic review was developed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The focused question was: Are fixed mandibular 3-implant retained prostheses safe and predicable for full-arch mandibular prostheses? The Medline/PubMed and Cochrane Library databases were used to conduct the systematic search for clinical trials on fixed mandibular 3-implant retained prostheses published between 1999 and 2020. Only English-language studies that presented information on implant and prosthetic survival were included., Results: A total of 302 studies were identified, of which 13 addressed the inclusion criteria. Additionally, 574 participants were included in these studies. As reported, 73 (4.57%) of 1596 implants failed, with a survival rate of 95.43%. In addition, the mean survival rate of the presented prostheses was 89.66%. The mean marginal bone loss was 1.09 mm., Conclusion: Within the limitations of the present review, implant and prosthetic survival rates of fixed mandibular 3-implant retained prostheses were similar to those of full-arch mandibular prostheses retained by four or more implants. Further research exploring the topic is necessary., (© 2020 by the American College of Prosthodontists.)

Context: Is it possible that the irrigating solutions can have the potential to cause post-operative pain? Unfortunately, the current literature does not provide clear guidance., Aim: The purpose of this systematic review and meta-analysis was to comprehensively review two different irrigation solutions (sodium hypochlorite and chlorhexidine) regarding the post-operative pain after endodontic treatment., Settings and Design: This study was prepared according to the Cochrane criteria for creating a systematic review and meta-analysis and confirms the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement., Material and Methods: This search was conducted in the PubMed/MEDLINE, SCOPUS and Cochrane Library databases until February 2018 to answer the In [(Population) what is the effect of (Intervention) on (Outcome), compared with (Comparison) Intervention] (PICO) question: could sodium hypochlorite cause more post-operative pain than chlorhexidine in teeth subjected to endodontic treatment? The primary outcome was overall post-operative pain after 24 h., Results: After applying the inclusion and exclusion criteria, three randomized clinical trials fulfilled the eligibility criteria, and two were subjected to the meta-analysis. There was no difference in post-operative pain between the tested irrigating solutions., Conclusions: There are few studies published in the current literature; therefore, additional randomized clinical studies are required to on this topic to help clinicians make the best decision concerning treatment., Competing Interests: None

Background: Extrusion of infected debris into the periapical tissue has been cited as the major cause of postoperative pain, regardless of instrumentation technique., Aim: Comprehensively review two different kinematics of instrumentation (reciprocating and rotary) and association to the postoperative pain after endodontic treatment., Methods: Two investigators performed a systematic review with meta-analysis. MEDLINE/PubMed, Cochrane Library, and Scopus supplied relevant data from studies published until February 2018 to answer the PICO question. Primary outcome was overall postoperative pain, and the secondary outcomes were nature of the pain (mild, moderate, and severe) at 12, 24, and 48 h., Results: Ten randomized clinical trials fulfilled eligibility criteria, and five of them were submitted in the meta-analysis. Primary outcome indicated that reciprocating system results in less postoperative pain compared to rotary system ( P < 0.05). As a secondary outcome, there was no statistical difference for mild, moderate, and severe pain after 12 and 24 h using reciprocating or rotary systems ( P > 0.05). However, the reciprocation system showed less severe pain after 48 h ( P < 0.05)., Conclusion: Rotary motion had a negative impact on postoperative pain after endodontic treatment. Furthermore, after 48 h, more patients presented severe pain under rotary motion. More randomized clinical studies would be helpful., Competing Interests: There are no conflicts of interest., (Copyright: © 2019 Journal of Conservative Dentistry.)

Statement of Problem: There is insufficient evidence to recommend the restorative material for implant-supported prostheses., Purpose: The purpose of this systematic review and meta-analysis was to evaluate studies that compared ceramic and metal-ceramic restorations for implant-supported prostheses (within the same study to avoid indirect comparison) in terms of the mechanical and biological complication rates, prosthesis survival rate, and marginal bone loss., Material and Methods: Two independent reviewers performed a comprehensive search in databases (PubMed/MEDLINE, Web of Science, and Cochrane Library) for articles indexed until March 31, 2018. The search was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and methods were registered in the International Prospective Register of Systematic Reviews (PROSPERO). The focused question was "Do ceramic restorations have mechanical/biological complication rates, prosthesis survival rates, and marginal bone loss similar to those of metal-ceramic restorations?", Results: The search identified 949 references. The interinvestigator agreement using kappa values was 0.87 for PubMed/MEDLINE, 0.93 for Scopus, and 1.0 for the Cochrane Library. After analysis, 12 studies were selected for qualitative and quantitative analysis. The mechanical complication rate did not differ between ceramic and metal-ceramic restorations (P=.89), independent of the type of prostheses (single crown: P=.63; fixed partial denture: P=.65). The biological complication rate was also not significantly different between ceramic and metal-ceramic restorations (P=.21). The prosthesis survival rate showed no significant differences between the 2 types of restorations (P=.56). Marginal bone loss was also similar for both types of restorations (P=.12)., Conclusions: This systematic review indicated that ceramic and metal-ceramic implant-supported prostheses have similar mechanical and biological complication rates, prosthesis survival rates, and marginal bone loss. Thus, both treatments are appropriate options for long-term rehabilitation treatment., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The decision to splint or to restore independently generally occurs during the planning stage, when the advantages and disadvantages of each clinical situation are considered based on the proposed treatment. However, clinical evidence to help clinicians make this decision is lacking., Purpose: The purpose of this systematic review and meta-analysis was to assess the marginal bone loss, implant survival rate, and prosthetic complications of splinted and nonsplinted implant restorations., Material and Methods: This study was designed according to the Cochrane criteria for elaborating a systematic review and meta-analysis and adopted the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Also, this review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42017080162). An electronic search in the PubMed/MEDLINE, Cochrane Library, and Scopus databases was conducted up to November 2017. A specific clinical question was structured according to the population, intervention, comparison, outcome (PICO) approach. The addressed focused question was "Should the restoration of adjacent implants be splinted or nonsplinted?" The meta-analysis was based on the Mantel-Haenszel and inverse variance methods to assess the marginal bone loss, implant survival, and prosthetic complications of splinted and nonsplinted implant restorations., Results: Nineteen studies were selected for qualitative and quantitative analyses. A total of 4215 implants were placed in 2185 patients (splinted, 2768; nonsplinted, 1447); the mean follow-up was 87.8 months (range=12-264 months). Quantitative analysis found no significant differences between splinted and nonsplinted restorations for marginal bone loss. The assessed studies reported that 75 implants failed (3.4%), of which 24 were splinted (99.1% of survival rate) and 51 were nonsplinted (96.5% of survival rate). Quantitative analysis of all studies showed statistically significant higher survival rates for splinted restorations than for nonsplinted restorations. Ceramic chipping, screw loosening, abutment screw breakage, and soft tissue inflammation were reported in the selected studies. The quantitative analysis found no statistically significant difference in the prosthetic complications of splinted and nonsplinted restorations., Conclusions: Within the limitations of this systematic review and meta-analysis, it was concluded that there was no difference in the marginal bone loss and prosthetic complications of splinted and nonsplinted implant restorations; this is especially true for restorations in the posterior region. However, splinted restorations were associated with decreased implant failure., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The purpose of this article was to present an alternative procedure using resin-based provisional material to create the posterior palatal seal (PPS). This method offers more practicality in clinical routine and increased control for addition of material to create the PPS when compared to traditional techniques such as the use of impression wax., (© 2017 by the American College of Prosthodontists.)

The aim of this study was to evaluate stress distribution in the implants/components and bone tissue for splinted and nonsplinted prostheses with different lengths of implants using three-dimensional finite element analysis. Six models from the posterior maxillary area were used in simulations. Each model simulated three Morse taper implants of 4.0 mm diameter with different lengths, which supported metal-ceramic crowns. An axial load of 400 N and an oblique load of 200 N were used as loading conditions. Splinted prostheses exhibited better stress distribution for the implants/components, whereas nonsplinted prostheses exhibited higher stress in the first molar under axial/oblique loading. Implant length did not influence stress distribution in the implants/components. In cortical bone tissue, splinted prostheses decreased the tensile stress in the first molar, whereas nonsplinted prostheses were subjected to higher tensile stress in the first molar; implant length had no influence on stress distribution. Within the limitations of this study, we conclude that splinted prostheses contributed to better stress distribution in the implant/abutment and cortical bone tissue; however, the reduction in the implant length did not influence the stress distribution.

The aim of this meta-analysis was to verify the clinical viability of single implant-retained mandibular overdentures (SIMO). An electronic search of the PubMed and Cochrane databases was performed (end date July 2017); this was supplemented by a manual search of the literature. Only prospective clinical trials and randomized controlled trials (RCTs) that evaluated SIMO with a minimum follow-up of 12 months were included. The meta-analysis was based on the Mantel-Haenszel method. Dental implant and prosthetic failure were the dichotomous outcome measures; these were evaluated through the risk ratio (RR) and odds ratio (OR), with corresponding 95% confidence intervals (CI). Of 499 articles identified, nine fulfilled the inclusion criteria. A total of 205 implants were placed in patients with a mean age of 64.1 years; the cumulative survival rate was 96.6% over a mean follow-up period of 37.3 months. The procedure used (SIMO vs. two implant-retained mandibular overdenture) did not affect dental implant failure (P=0.45) or prosthetic failure (P=0.65): RR 1.06 (95% CI 0.91-1.23) and RR 0.88 (95% CI 0.51-1.51), respectively; OR 2.56 (95% CI 0.27-24.39; P=0.41) and OR 0.44 (95% CI 0.15-1.26; P=0.13), respectively. Within the limitations of this systematic review and meta-analysis, SIMO with a complete denture as the opposing arch may be considered an alternative treatment for completely edentulous patients. However, this study also confirmed the need for more RCTs on this topic., (Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study was to analyze the stress distribution of bone tissue around implants with different implant-abutment interfaces: platform switching (PSW); external hexagon (EH) and Morse taper (MT) with different diameters (regular: Ø 4 mm and wide: Ø 5 mm), bone types (I-IV) and subjected to axial and oblique load conditions using three-dimensional finite element analysis (3D-FEA). Sixteen 3D models of various configurations were simulated using InVesalius, Rhinoceros 3D 4.0, and SolidWorks 2011 software, and processed using Femap 11.2 and NeiNastran 11.0 programs. Axial and oblique forces of 200 N and 100 N, respectively, applied at the occlusal surface of prostheses. Maximum principal stress values were obtained from the peri-implant cortical bone of each model. Statistical analyses were performed using ANOVA and Tukey's test for maximum principal stress values. Oblique loading showed higher tensile stress than axial loading (P < 0.001). Wide-diameter implants showed lower stress concentration rather than regular-diameter implants, regardless of both connection and bone type (P < 0.001). Under axial loading, wide-diameter EH implants with regular platforms showed more favorable stress distribution than PSW implants for axial loading (P < 0.001); however, under oblique loading, PSW implants exhibited lower stress concentrations (P < 0.001). Regular-diameter MT implants showed lower stress than EH implants (P < 0.001). Bone type IV showed higher stress in the cortical region than bone types I and II (P < 0.001), but no significant difference when compared with bone type III (P > 0.05). The conclusion drawn from this in silico is that MT implants should be considered for use in situations that preclude the placement of wide-diameter implants, particularly where bone types III and IV are concerned., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The aim of this study was to compare the values of bone-implant contact (BIC) and removal torque (RTQ) reported in different animal studies for titanium-zirconium (TiZr) and titanium (Ti) dental implants. This review has been registered at PROSPERO under number CRD42016047745. We undertook an electronic search for data published up until November 2017 using the PubMed/Medline, Embase, and The Cochrane Library databases. Eligibility criteria included in vivo studies, comparisons between Ti and TiZr implants in the same study, and studies published in English that evaluated BIC and RTQ. After inclusion criteria, 8 studies were assessed for eligibility. Of the 8 studies, 7 analyzed BIC outcome and 3 analyzed RTQ outcome. Among such studies, 6 studies were considered for meta-analysis of quantitative for BIC and 2 studies for RTQ. There was no significant difference for BIC analysis ( P = .89; random ration [RR]: -0.21; 95% confidence interval [CI]: -3.14 to 2.72). The heterogeneity of the primary outcome studies was considered low (7.19; P = .21; I 2 : 30%). However, the RTQ analysis showed different results favoring the TiZr dental implants ( P = .001; RR: 23.62; 95%CI: 9.15 to 38.10). Low heterogeneity was observed for RTQ (χ 2 : 1.25; P = .26; I 2 : 20%). Within the limitations of this study, there was no difference between TiZr and Ti alloys implants in terms of BIC. However, TiZr implants had higher RTQ than Ti alloys.

Purpose: To characterize the surface of glass fiber posts (GFP) after different surface treatments and evaluate which method incorporates higher amounts of silicon (Si) particles, as well as to evaluate the bond strength at the post/ composite-cement interface with four different surface treatments of glass fiber posts luted with composite cement., Materials and Methods: Twelve glass fiber posts were obtained from the manufacturer. The posts were randomly distributed into four groups (n = 3): Co (control), no surface treatment; S, 70% alcohol and silane (60 s); HF + S, 10% hydrofluoric acid gel (60 s) and silane (60 s); NTP, nonthermal plasma of hexamethyldisiloxane (HMDSO) associated with argon (30 min). The surface of each GFP was characterized through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Forty GFPs were randomly divided into 4 groups according the surface treatments (n = 10) and cemented with one composite cement (Rely X U200) into artificial canine teeth. The specimens were placed in a universal testing machine and subjected to tensile testing until failure occurred. Statistical analysis of the atomic percentage and bond strength was performed using ANOVA, followed by the post-hoc Tukey test (p = 0.05)., Results: EDS graphics showed that the NTP group had a higher Si atomic percentage (at%) than the other groups (p < 0.001). The HF + S group had a higher Si at% than did the Co and S groups. SEM images illustrated that the surfaces of the GFPs were variously modified after different treatments. The NTP group incorporated higher Si levels on the GFP surface and yielded the highest bond strengths (p < 0.005) compared to the other tested groups., Conclusion: Treatment with HMDSO + Ar plasma (NTP) incorporated higher Si levels on the surface of the GFPs without inducing critical defects. NTP treatment promoted better bond strength results when compared to the other tested group when GFPs were cemented with composite cement.

The aim of the authors was to report a clinical case about immediate implant placement after the removal of complex odontoma. A 35-year-old female patient presented to private service complaining about absence of lower right first premolar. The computed tomographic showed radiopaque attenuation, surrounded by a narrow radiolucency in the area of dental absence, suggesting a mineralized lesion. The surgical removal of lesion was performed by intraoral access with general anesthesia and the implant of 3.75 × 10 mm (Neodent) was placed with the aid of a surgical guide, following the drill sequence established by the manufacturer. No complications were observed after 1 year with the prosthetic rehabilitation.

The aim of this study was to evaluate different materials for restoration of teeth without ferrule by three-dimensional (3D) finite element analysis (FEA). Five models simulating the maxillary central incisor and surrounding bone were simulated according to the type of post: glass fibre post (GFP) or cast metal post (CMP) with different alloys such as gold (Au), silver-palladium (AgPd), copper-aluminum (CuAl) and nickel-chromium (NiCr). Models were designed using Invesalius and Rhinoceros. FEAs were made using FEMAP and NeiNastran, with an applied axial force of 100 N and oblique occlusal load at 45°. Stress distribution among groups was analysed by two-way analysis of variance (ANOVA), followed by post-hoc Tukey's test. The GFP showed the best stress distribution in the post, followed by CMP with Au, AgPd, CuAl and NiCr alloys, respectively (p < .001). No statistically significant difference in the stress distribution in teeth was found under application of axial load (p > .05). Under oblique load, the GFP generated the highest values of tension among the models, followed by the CMP with NiCr alloy than other models (p < .001). The use of GFP resulted in a lower stress concentration in the post, but increased stress in the tooth without ferrule. The CMP with NiCr alloy exhibited the highest stress distribution among other CMP. To avoid higher stress in teeth, alloys of Au, AgPd and CuAl, respectively, are recommended.

Statement of Problem: Slight offset of the central implant in 3-unit implant-supported prostheses has been reported to improve biomechanical behavior. However, studies that assessed the effects of an offset implant configuration in the posterior maxilla are scarce., Purpose: The purpose of this 3-dimensional (3D) finite element analysis was to assess the effects of splinting in 3-unit implant-supported prostheses with varying implant positions (straight-line or offset configuration) in terms of the stress/strain distribution on bone tissue and the stress distribution on abutment screws., Material and Methods: Three 3D models were used to simulate a posterior maxilla bone block (type IV): straight-line implants supporting single crowns (model M1), straight-line implants supporting 3-unit splinted fixed dental prosthesis (model M2), and an offset implant configuration supporting 3-unit splinted fixed dental prosthesis (model M3). The applied forces were 400 N axially and 200 N obliquely. The type of implant platform simulated was an external hexagon. von Mises stress on the abutment screws was measured, and the maximum principal stress and microstrain values were used to perform cortical bone tissue analysis. Analysis of variance (ANOVA) and the Tukey honest significant differences post hoc test were used to determine the significance of the results and interactions among the main variables (α=.05)., Results: In all models, oblique load increased the stress on abutment screws and bone tissue and the microstrain on bone tissue. Model M3 decreased the stress concentration on the abutment screws and bone tissue. With regard to microstrain distribution, model M3 had the smallest values, and M1 and M2 had similar values., Conclusions: Splinting associated with an offset implant configuration was effective for decreasing the stress on abutment screws and bone tissue and the microstrain on bone tissue., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The longevity of silicone facial prostheses is short, and published data concerning this type of rehabilitation are limited., Purpose: The purpose of this retrospective study was to identify predictive variables for prosthetic failure and to highlight the results that can be expected after treatment with silicone facial prostheses., Material and Methods: After institutional approval, patient records from a single Brazilian institution for the time period 2004 to 2015 were assessed. A standardized form was used to collect patient data. Frailty survival modeling (simple random effects survival model) was used to test whether age, sex, type of prosthesis, source of defect, number of implants, and type of retention have a direct impact on the prosthetic failure rate (α=.05)., Results: Auricular prostheses were the most frequently fabricated prostheses. Eighty-four prostheses were fabricated during the follow-up period. The overall survival rate for facial prostheses was 34.5%. Color alteration was the most common reason for new prostheses (27.38%). The implant success rate was 98.18%. The number of implants approached statistical significance (P=.06) with a reduced risk of failure when the patient had 2 implants compared with patients with zero implants and patients with more than 2 implants., Conclusions: Patients should be recalled frequently so that retouches can be performed, avoiding the repeated fabrication of new prostheses. Well-designed studies are necessary to identify more relevant complications and factors that lead to prosthetic failure., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to use three-dimensional finite element analysis to analyze the stress distribution transferred by single implant-supported prostheses placed in the anterior maxilla using different connections (external hexagon, internal hexagon, or Morse taper), inclinations of the load (0, 30, or 60 degrees), and surgical techniques for placement (monocortical/conventional, bicortical, or bicortical with nasal floor elevation)., Materials and Methods: Nine models representing a bone block of this region were simulated by computer-aided design software (InVesalius, Rhinoceros, SolidWorks). Each model received one implant, which supported a cemented metalloceramic crown. Using FEMAP software, finite elements were discretized while simulating a 178-N load at 0, 30, and 60 degrees relative to the long axis of the implant. The problem was solved in NEi Nastran software, and postprocessing was performed in FEMAP. Von Mises stress and maximum principal stress maps were made., Results: The von Mises stress analysis revealed that stress increased with increasing inclination of the load, from 0 to 30 to 60 degrees. Morse taper implants showed less stress concentration around the cervical and apical areas of the implant. The bicortical technique, associated or not with nasal floor elevation, contributed to decreasing the stress concentration in the apical area of the implant. Maximum principal stress analysis showed that the increase in inclination was proportional to the increase in stress on the bone tissue in the cervical area. Lower stress concentrations in the cortical bone were obtained with Morse taper implants and the bicortical technique compared with other connections and surgical techniques, respectively., Conclusion: Increasing the inclination of the applied force relative to the long axis of the implant tended to overload the peri-implant bone tissue and the internal structure of the implants. The Morse taper connection and bicortical techniques seemed to be more favorable than other connections or techniques, respectively, for restoring the anterior maxilla.

The aim of this study was to report a patient of rehabilitation with removable partial denture retained by implants in-patient who suffered injury after firearm shooting. A 19-year-old man presented to the hospital of the Val Paraíso city after being hit by a bullet in the right on the face, affecting the teeth 12 to 16. The surgery to remove the shards of teeth, and bullet was performed. Surgical team opted for installation of implants without bone grafts; however, due to extensive loss of alveolar bone, only 3 tilted implants (2 Ø3.75 × 8.5 mm and 1 Ø3.75 × 10 mm) were installed. After recovery, the patient was referred to the Araçatuba Dental School-UNESP for the rehabilitation on the affected region. The difficulty of rehabilitation with conventional fixed prostheses was verified during the prosthetic phase. This way, it was opted for rehabilitation with removable partial dentures associated with dental implant. Two attachment system ERA (ERA, Sterngold) were positioned in the bar to make the removable partial denture. After 5 years of follow-up, the authors can conclude that the use of removable partial denture retained by implants is effective for functional and aesthetic rehabilitation, favoring socialization and self-esteem of the patient.

The aim of this study was to evaluate the influence of pontic and cantilever designs (mesial and distal) on 3-unit implant-retained prosthesis at maxillary posterior region verifying stress and strain distributions on bone tissue (cortical and trabecular bones) and stress distribution in abutments, implants and fixation screws, under axial and oblique loadings, by 3D finite element analysis. Each model was composed of a bone block presenting right first premolar to the first molar, with three or two external hexagon implants (4.0 × 10 mm), supporting a 3-unit splinted dental fixed dental prosthesis with the variations: M1 - three implants supporting splinted crowns; M2 - two implants supporting prosthesis with central pontic; M3 - two implants supporting prosthesis with mesial cantilever; M4 - two implants supporting prosthesis with distal cantilever. The applied forces were 400 N axial and 200 N oblique. The von Mises criteria was used to evaluate abutments, implants and fixation screws and maximum principal stress and microstrain criteria were used to evaluate the bone tissue. The decrease of the number of implants caused an unfavorable biomechanical behavior for all structures (M2, M3, M4). For two implant-supported prostheses, the use of the central pontic (M2) showed stress and strain distributions more favorable in the analyzed structures. The use of cantilever showed unfavorable biomechanical behavior (M3 and M4), mainly for distal cantilever (M4). The use of three implants presented lower values of stress and strain on the analyzed structures. Among two implant-supported prostheses, prostheses with cantilever showed unfavorable biomechanical behavior in the analyzed structures, especially for distal cantilever.

Statement of Problem: Currently, which type of suprastructure is preferred when fabricating implant-retained craniofacial prostheses is unknown., Purpose: The purpose of this systematic review was to identify the best retention system (bar-clips versus magnets) for implant-retained craniofacial prostheses., Material and Methods: This systematic review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A systematic search of Medline/PubMed and Web of Science databases for clinical trials was conducted on implant-retained craniofacial prostheses published between 2005 and 2015. English-language studies that directly compared different types of retention systems or presented information on implant survival, periimplant soft tissue reactions, and prosthetic complications were included. Nonclinical studies were excluded to eliminate bias., Results: A total to 173 studies were identified, of which 10 satisfied the inclusion criteria. In total, 492 participants were included in these studies. Four selected studies displayed detailed information with regard to the number of implant failures according to the retention system. As reported, 29 (18.2%) of 159 implants with magnets failed, whereas 25 (31.6%) of 79 implants with bars failed. Overall auricular superstructures showed the highest survival (99.08%). In addition, 55.4% of all participants in the selected studies showed grade 0 of periimplant soft tissue reactions., Conclusions: A systematic search for clinical studies resulted in few studies with a short-term follow-up and small number of participants. The limited data collected indicated that magnets show fewer complications than bar superstructures; however, no hard conclusions could be drawn. Further research, preferably in the form of clinical trials, is needed to validate these findings., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The aim of study was to evaluate the stress distribution in implant-supported prostheses and peri-implant bone using internal hexagon (IH) implants in the premaxillary area, varying surgical techniques (conventional, bicortical and bicortical in association with nasal floor elevation), and loading directions (0°, 30° and 60°) by three-dimensional (3D) finite element analysis. Three models were designed with Invesalius, Rhinoceros 3D and Solidworks software. Each model contained a bone block of the premaxillary area including an implant (IH, Ø4 × 10 mm) supporting a metal-ceramic crown. 178 N was applied in different inclinations (0°, 30°, 60°). The results were analyzed by von Mises, maximum principal stress, microstrain and displacement maps including ANOVA statistical test for some situations. Von Mises maps of implant, screws and abutment showed increase of stress concentration as increased loading inclination. Bicortical techniques showed reduction in implant apical area and in the head of fixation screws. Bicortical techniques showed slight increase stress in cortical bone in the maximum principal stress and microstrain maps under 60° loading. No differences in bone tissue regarding surgical techniques were observed. As conclusion, non-axial loads increased stress concentration in all maps. Bicortical techniques showed lower stress for implant and screw; however, there was slightly higher stress on cortical bone only under loads of higher inclinations (60°).

A biomechanical analysis of different types of implant connections is relevant to clinical practice because it may impact the longevity of the rehabilitation treatment. Therefore, the objective of this study is to evaluate the Morse taper connections and the stress distribution of structures associated with the platform switching (PSW) concept. It will do this by obtaining data on the biomechanical behavior of the main structure in relation to the dental implant using the 3-dimensional finite element methodology. Four models were simulated (with each containing a single prosthesis over the implant) in the molar region, with the following specifications: M1 and M2 is an external hexagonal implant on a regular platform; M3 is an external hexagonal implant using PSW concept; and M4 is a Morse taper implant. The modeling process involved the use of images from InVesalius CT (computed tomography) processing software, which were refined using Rhinoceros 4.0 and SolidWorks 2011 CAD software. The models were then exported into the finite element program (FEMAP 11.0) to configure the meshes. The models were processed using NeiNastram software. The main results are that M1 (regular diameter 4mm) had the highest stress concentration area and highest microstrain concentration for bone tissue, dental implants, and the retaining screw (P<0.05). Using the PSW concept increases the area of the stress concentrations in the retaining screw (P<0.05) more than in the regular platform implant. It was concluded that the increase in diameter is beneficial for stress distribution and that the PSW concept had higher stress concentrations in the retaining screw and the crown compared to the regular platform implant., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The aim of this study was to assess stress/strain of different implant modeling simplifications by 3D-FEA. Three variation of external hexagon implant (Ø3.75 × 10 mm) supporting one molar crown were simulated: A (no threads); B (slightly threads simplification); C (original design). 200 N (axial) and 100 N (oblique) were applied. Cortical bone was evaluated by maximum principal stress and microstrain qualitatively and quantitatively (ANOVA and Tukey post hoc (p < 0.05)). Higher stress levels (p < 0.05) were observed in model A. Models B and C presented similar stress transmission. It was possible to conclude that slightly simplification should be used for studies evaluating stress transferring for bone tissue.

This article reports a case of oral rehabilitation with two-implant-retained mandibular overdenture using bar/clip and ball attachment bilaterally on the distal side. A patient aged 69 years, fully edentulous, presented herself to private practice complaining about the instability of mandibular denture. Several possibilities of rehabilitation with advantages and disadvantages were explained to the patient, based in the clinical and radiograph examinations, and patient desire, in which she opted by conventional maxillary complete denture and two-implant-retained mandibular overdenture. Two external hexagon implants of 3.75 × 10 mm were placed in anterior area of mandible. The fabrication of the metal framework with bar/clip and ball attachment bilaterally on the distal side was planned based on prior arrangement of the artificial teeth. Internal adaptation and occlusal adjustments were performed in the day of insertion of finalized denture and instructions about maintenance and sanitation. The patient showed satisfaction with the final result of her treatment, and no complications were observed during this period. The association of bar/clip with ball system may be viable as option of retention for mandibular implant-retained complete overdenture; however, further randomized controlled trials are necessary to obtain detailed knowledge about the topic.

The aim of this study is to assess the effect of different dental implant designs, bone type, loading, and surface treatment on the stress distribution around the implant by using the 3D finite-element method. Twelve 3D models were developed with Invesalius 3.0, Rhinoceros 4.0, and Solidworks 2010 software. The analysis was processed using the FEMAP 10.2 and NeiNastran 10.0 software. The applied oblique forces were 200 N and 100 N. The results were analyzed using maps of maximum principal stress and bone microstrain. Statistical analysis was performed using ANOVA and Tukey's test. The results showed that the Morse taper design was most efficient in terms of its distribution of stresses (p<0.05); the external hexagon with platform switching did not show a significant difference from an external hexagon with a standard platform (p>0.05). The different bone types did not show a significant difference in the stress/strain distribution (p>0.05). The surface treatment increased areas of stress concentration under axial loading (p<0.05) and increased areas of microstrain under axial and oblique loading (p<0.05) on the cortical bone. The Morse taper design behaved better biomechanically in relation to the bone tissue. The treated surface increased areas of stress and strain on the cortical bone tissue., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Statement of Problem: No consensus has been reached on which retention system, cement- or screw-retained, is best to avoid bone loss around the implant of a fixed implant-supported restoration., Purpose: The purpose of this systematic review and meta-analysis was to compare cement- and screw-retained retention systems in fixed implant-supported restorations in terms of marginal bone loss, implant survival, and prosthetic complications., Material and Methods: A comprehensive search of studies published from January 1995 to March 2015 and listed in the PubMed/MEDLINE, Embase, Scopus and the Cochrane Library databases was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The meta-analysis was based on the Mantel-Haenszel and inverse variance methods. Marginal bone loss was the continuous outcome measure evaluated by mean difference (MD), and implant survival and prosthetic complications were the dichotomous outcome measures evaluated by risk ratio (RR), both with corresponding 95% confidence intervals (CI)., Results: The 20 studies selected for review evaluated 2139 participants, whose mean age was 47.14 years and who had received 8989 dental implants. The mean follow-up was 65.4 months (range: 12-180 months). Results of the MD for marginal bone loss showed statistically significant differences in favor of the cement-retained prosthesis (P =.04; MD: -0.19; CI: -0.37 to -0.01). The implant survival rate was higher for the cement-retained prosthesis (P =.01; RR: 0.49; CI: 0.28 to 0.85), and the prosthetic complication rate was higher for the screw-retained prosthesis (P =.04; RR: 0.52; CI: 0.28 to 0.98). Additional analysis of the mean plaque index did not show differences between retention systems (P=.58; MD: 0.13; CI: -0.32 to 0.57)., Conclusions: The current meta-analysis indicated that cement-retained, fixed implant-supported restorations showed less marginal bone loss than screw-retained, fixed implant-supported restorations during the follow-up period, which ranged from 12 to 180 months. However, the small difference between the mean values may not show clinical significance. The rates of prosthetic complication and implant survival also compared favorably with cement-retained prostheses., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to analyze the stress distribution of short implants supporting single unit or splinted crowns by the photo-elasticity method. Four photo-elastic models were produced: A (3.75×7 mm); B (3.75×7 mm, 3.75×7 mm and 3.75×7 mm); C (3.75×10 mm, 3.75×7 mm and 3.75×7 mm); D (3.75×13 mm, 3.75×7 mm and 3.75×7 mm). The prostheses were made with Ni-Cr alloy. A load of 100 N in the axial and oblique directions was applied, totaling 380 applications, individually capturing their images in each model. The data were randomized and analyzed qualitatively and quantitatively by 2 examiners. The oblique loading was significantly more damaging. The increase in length was favorable for stress distribution (p<0.05). The splinting was beneficial for the transmission of stresses mainly (p<0.05). The splinting of the crowns, as well as increasing the length of the first implant and axial loading was most beneficial in the stress distribution. Short splinted implants behaved better than single unit implants. Increasing of the length of the first implant significantly improved the stress distribution in all analyzed situations., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The study of short implants is relevant to the biomechanics of dental implants, and research on crown increase has implications for the daily clinic. The aim of this study was to analyze the biomechanical interactions of a singular implant-supported prosthesis of different crown heights under vertical and oblique force, using the 3-D finite element method. Six 3-D models were designed with Invesalius 3.0, Rhinoceros 3D 4.0, and Solidworks 2010 software. Each model was constructed with a mandibular segment of bone block, including an implant supporting a screwed metal-ceramic crown. The crown height was set at 10, 12.5, and 15 mm. The applied force was 200 N (axial) and 100 N (oblique). We performed an ANOVA statistical test and Tukey tests; p<0.05 was considered statistically significant. The increase of crown height did not influence the stress distribution on screw prosthetic (p>0.05) under axial load. However, crown heights of 12.5 and 15 mm caused statistically significant damage to the stress distribution of screws and to the cortical bone (p<0.001) under oblique load. High crown to implant (C/I) ratio harmed microstrain distribution on bone tissue under axial and oblique loads (p<0.001). Crown increase was a possible deleterious factor to the screws and to the different regions of bone tissue., (Copyright © 2014 Elsevier Ltd. All rights reserved.)