Publications by authors named "Ana Messias"

51 Publications

Influence of Preoperative Pulp Inflammation in the Outcome of Full Pulpotomy Using a Dog Model.

J Endod 2021 Jul 3. Epub 2021 Jul 3.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Center for Innovation and Research in Oral Sciences, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

Introduction: This study aimed to evaluate the impact of preoperative pulp inflammation on the histologic outcome of full pulpotomy performed in mature permanent posterior teeth using 4 different biomaterials.

Methods: Five beagle dogs (providing a total of 120 roots) were selected. Dentin exposure was performed in teeth from the second and third quadrants. One week later, full pulpotomy procedures were performed using 4 different bioactive materials (ProRoot MTA [MTA], TotalFill BC Putty [BC], Biodentine [BIO], and an experimental cement [ie, pulp capping material]). The hemostasis time was registered. After 14 weeks, the animals were killed. Pulp-dentin tissues were histologically and radiographically assessed. The significance level was set at .05.

Results: Teeth with previously exposed dentin revealed a statistically significant increase in the time required to achieve hemostasis (P < .001), therefore confirming the pulp inflammation status induced by 1-week exposure of occlusal dentin before performing full pulpotomy. There was no radiographic evidence of root resorption, periapical radiolucency, or lamina dura alterations. No statistically significant differences were observed between normal and inflamed pulp regardless of the evaluated histologic parameters. Moreover, histologic data concerning calcified barrier formation and the pulp tissue response show better results for BIO without statistical differences compared with MTA or BC (P > .05). The pulp capping material presented a lower performance, with statistically significant differences being detected in regard to the remaining 3 tested materials (P < .001).

Conclusions: Radiographic and histologic outcomes of full pulpotomy are not jeopardized by short-term preoperative pulp inflammation. Moreover, BIO, MTA, and BC cements present suitable alternatives to be used as pulp capping agents.
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http://dx.doi.org/10.1016/j.joen.2021.06.018DOI Listing
July 2021

Clinical and radiographic performance of self-locking conical connection implants in the posterior mandible: Five-year results of a two-centre prospective study.

Clin Oral Implants Res 2021 Jun 11. Epub 2021 Jun 11.

Department of Oral and Maxillofacial Surgery, Johannes Gutenberg-University Medical Centre, Mainz, Germany.

Objective: This prospective study aims to assess the 5-year clinical performance of implants with internal conical connection and platform-switched abutments in the posterior mandible.

Material And Methods: Healthy adults missing at least two teeth in the posterior mandible and with a natural tooth mesial to the implant site received two or three adjacent implants. After a transmucosal healing period single crown restorations were cemented on platform-switched abutments. Changes in marginal bone levels were investigated in standardized periapical radiographs from surgery and loading (baseline) to 60-months post-loading.

Results: Twenty-four patients received 52 implants. Bone remodelling took place between surgery and loading (mean:-0.5, SD:±0.4 mm). From loading to 60 months, there was a mean bone change of 0.27 (SD:±0.47 mm) which stabilized 24 months after prosthesis delivery (mean:0.2, SD:±0.46 mm). 71.7% of all implants presented bone preservation at 60 months irrespective of the initial insertion depth. Two implants were lost after 5 years and the success rate was 95.1%. Patient enquiry revealed high satisfaction.

Conclusion: Internal conical connection implants with platform-switched abutments presented a high success rate and preservation of marginal bone levels at the implant shoulder after 5 years of loading.
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http://dx.doi.org/10.1111/clr.13794DOI Listing
June 2021

Latent leprosy infection identified by dual RLEP and anti-PGL-I positivity: Implications for new control strategies.

PLoS One 2021 13;16(5):e0251631. Epub 2021 May 13.

Colorado State University, Department of Microbiology, Immunology and Pathology, Mycobacteria Research Laboratories, Fort Collins, CO, Unites States of America.

The number of new cases of leprosy reported worldwide has remained essentially unchanged for the last decade despite continued global use of free multidrug therapy (MDT) provided to any diagnosed leprosy patient. In order to more effectively interrupt the chain of transmission, new strategies will be required to detect those with latent disease who contribute to furthering transmission. To improve the ability to diagnose leprosy earlier in asymptomatic infected individuals, we examined the combined use of two well-known biomarkers of M. leprae infection, namely the presence of M. leprae DNA by PCR from earlobe slit skin smears (SSS) and positive antibody titers to the M. leprae-specific antigen, Phenolic Glycolipid I (anti-PGL-I) from leprosy patients and household contacts living in seven hyperendemic cities in the northern state of Pará, Brazilian Amazon. Combining both tests increased sensitivity, specificity and accuracy over either test alone. A total of 466 individuals were evaluated, including 87 newly diagnosed leprosy patients, 52 post-treated patients, 296 household contacts and 31 healthy endemic controls. The highest frequency of double positives (PGL-I+/RLEP+) were detected in the new case group (40/87, 46%) with lower numbers for treated (12/52, 23.1%), household contacts (46/296, 15.5%) and healthy endemic controls (0/31, 0%). The frequencies in these groups were reversed for double negatives (PGL-I-/RLEP-) for new cases (6/87, 6.9%), treated leprosy cases (15/52, 28.8%) and the highest in household contacts (108/296, 36.5%) and healthy endemic controls (24/31, 77.4%). The data strongly suggest that household contacts that are double positive have latent disease, are likely contributing to shedding and transmission of disease to their close contacts and are at the highest risk of progressing to clinical disease. Proposed strategies to reduce leprosy transmission in highly endemic areas may include chemoprophylactic treatment of this group of individuals to stop the spread of bacilli to eventually lower new case detection rates in these areas.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251631PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8118453PMC
May 2021

Different Interventions for Rehabilitation of the Edentulous Maxilla with Implant-Supported Prostheses: An Overview of Systematic Reviews.

Int J Prosthodont 2021 Suppl;34:s63-s84

Purpose: To synthesize evidence derived from systematic reviews (SRs) on different interventions for rehabilitation of the edentulous maxilla with implant-supported restorations.

Materials And Methods: A protocol-oriented search was established to address the PICO question: What is the current evidence regarding rehabilitation of the edentulous maxilla with different implant-supported prostheses in terms of implant and prosthesis survival? The primary outcomes were implant and prosthesis survival rates evaluated from SRs of clinical studies including adult patients with complete edentulism of the maxilla and comparing different implant-supported rehabilitation strategies. Methodologic quality of the SRs was assessed with the AMSTAR-2 tool.

Results: The final selection process led to the inclusion of 36 SRs that were grouped as: (1) addressing maxillae with sufficient bone to place implants; (2) addressing maxillae with insufficient bone to place implants; and (3) comparing different types of prosthesis, number of implants, patient-reported outcomes, and economic evaluations. The literature describes four or more implants as suitable for full-arch fixed prostheses and implant-supported overdentures; in both cases, the overall survival rate is > 95%. Mini-implants present very high short-term failure rates (> 30%). Poor description of technical complications, adjustments, and maintenance and corresponding costs precluded a cost-effectiveness analysis.

Conclusion: No implant-supported rehabilitation of the edentulous maxilla (fixed or removable) should be supported on fewer than four implants. A one-piece full-arch fixed dental prosthesis can be supported by a minimum of two anterior axial plus two posterior distally tilted implants or by six to eight axial implants symmetrically distributed through the posterior and anterior regions of the arch. Four to six implants is the advised number to support an overdenture. The use of mini-implants in the maxilla is inadvisable.
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http://dx.doi.org/10.11607/ijp.7162DOI Listing
February 2021

Recommendations for Implant-Supported Full-Arch Rehabilitations in Edentulous Patients: The Oral Reconstruction Foundation Consensus Report.

Int J Prosthodont 2021 Suppl;34:s8-s20

The tasks of Working Groups 1 to 6 at the 4th Consensus Meeting of the Oral Reconstruction Foundation were to elucidate clinical recommendations for implant-supported full-arch rehabilitations in edentulous patients. Six systematic/narrative reviews were prepared to address the following subtopics: (1) the influence of medical and geriatric factors on implant survival; (2) the prevalence of peri-implant diseases; (3) the influence of material selection, attachment type, interarch space, and opposing dentition; (4) different interventions for rehabilitation of the edentulous maxilla; (5) different interventions for rehabilitation of the edentulous mandible; and (6) treatment choice and decision-making in elderly patients. Consensus statements, clinical recommendations, and implications for future research were determined based on structured group discussions and plenary session approval.
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http://dx.doi.org/10.11607/ijp.consensusreportDOI Listing
February 2021

The dynamics of linear polyubiquitin.

Sci Adv 2020 Oct 14;6(42). Epub 2020 Oct 14.

Department of Chemistry and Institute for Advanced Study, Technical University of Munich, Garching 85747, Germany.

Polyubiquitin chains are flexible multidomain proteins, whose conformational dynamics enable them to regulate multiple biological pathways. Their dynamic is determined by the linkage between ubiquitins and by the number of ubiquitin units. Characterizing polyubiquitin behavior as a function of their length is hampered because of increasing system size and conformational variability. Here, we introduce a new approach to efficiently integrating small-angle x-ray scattering with simulations allowing us to accurately characterize the dynamics of linear di-, tri-, and tetraubiquitin in the free state as well as of diubiquitin in complex with NEMO, a central regulator in the NF-κB pathway. Our results show that the behavior of the diubiquitin subunits is independent of the presence of additional ubiquitin modules and that the dynamics of polyubiquitins with different lengths follow a simple model. Together with experimental data from multiple biophysical techniques, we then rationalize the 2:1 NEMO:polyubiquitin binding.
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http://dx.doi.org/10.1126/sciadv.abc3786DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7556843PMC
October 2020

Different retinopathy phenotypes in type 2 diabetes predict retinopathy progression.

Acta Diabetol 2021 Feb 6;58(2):197-205. Epub 2020 Oct 6.

AIBILI - Association for Innovation and Biomedical Research on Light and Image, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.

Purpose: To characterize the progression in retinopathy severity of different phenotypes of mild nonproliferative diabetic retinopathy (NPDR) in patients with type 2 diabetes.

Design And Methods: Patients with type 2 diabetes and mild NPDR (ETDRS 20 or 35) were followed in a 5-year longitudinal study. Examinations, including color fundus photography (CFP) and optical coherence tomography (OCT and OCTA), were performed at baseline, 6 months and then annually. Phenotype classification was performed based on microaneurysm turnover (MAT, on CFP) and central retinal thickness (CRT, on OCT). Phenotype A is characterized by low MAT (< 6) and normal CRT; Phenotype B by low MAT (< 6) and increased CRT; and Phenotype C by higher MAT (≥ 6) with or without increased CRT. ETDRS grading of seven fields CFP was performed at the initial and last visits.

Results: Analysis of ETDRS grade step changes showed significant differences in diabetic retinopathy (DR) progression between the different phenotypes (p < 0.001). Of the 66 participants with phenotype A only 2 eyes (3%) presented 2-or-more-step worsening. None of the 50 participants characterized as phenotype B developed 2-step worsening, whereas 13 eyes (23.2%) characterized as phenotype C had 2-or-more-steps worsening. Phenotype C presents the higher risk for 2-or-more step worsening (OR: 15.94 95% CI: 3.45-73.71; p < 0.001) and higher sensitivity, correctly identifying 86.7% of cases at risk (AUC: 0.84 95% CI: 0.72-0.96; p < 0.001). Diabetic retinopathy severity progression was associated with HbA (p = 0.019), LDL levels (p = 0.043), and ocular factors as MAT (p = 0.010), MA formation rate (p = 0.014) and MA disappearance rate (p = 0.005). Capillary closure at 5-year follow-up, identified by lower vessel density (VD) on OCTA, was also associated with diabetic DR severity progression (p = 0.035).

Conclusions: Different DR phenotypes in type 2 diabetes show different risks of retinopathy progression. Phenotype C is associated with increased HbA values and presents a higher risk of a 2-or-more-step worsening of the ETDRS severity score.
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http://dx.doi.org/10.1007/s00592-020-01602-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7889686PMC
February 2021

Present Status in Polymeric Mouthguards. A Future Area for Additive Manufacturing?

Polymers (Basel) 2020 Jul 3;12(7). Epub 2020 Jul 3.

Department of Mechanical Engineering, University of Coimbra, CEMMPRE, 3030-788 Coimbra Portugal.

Athletes from contact sports are more prone to orofacial injuries because of the exposure to possible shocks and collisions derived from physical proximity. The use of protector polymeric mouthguards proved to be useful in the prevention of the described injuries. There are different types of mouthguards with varying ranges of protection and prices, but they are all made from polymers and share the same propose: to absorb and dissipate the impact energy resulting from the shocks. As they are used inside the mouth, they should not impair breathing and speaking nor compromise the comfort of the athlete. However, the ideal mouthguard is yet to be created. The choice of the most appropriate polymeric material and the standard required properties have not yet been reported. Regardless of the numerous studies in this field, normalized control parameters for both material characterization and mouthguard fabrication are absent. This paper aims to present a review of the current types of available mouthguards and their properties/characteristics. Moreover, a detailed description of the most common polymers for the fabrication of mouthguards, together with the manufacturing techniques, are discussed.
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http://dx.doi.org/10.3390/polym12071490DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407806PMC
July 2020

Retinopathy Phenotypes in Type 2 Diabetes with Different Risks for Macular Edema and Proliferative Retinopathy.

J Clin Med 2020 May 12;9(5). Epub 2020 May 12.

AIBILI-Association for Innovation and Biomedical Research on Light and Image, 3000-548 Coimbra, Portugal.

Our group reported that three diabetic retinopathy (DR) phenotypes: A, characterized by low microaneurysm turnover (MAT < 6) and normal central retinal thickness (CRT); B, low MAT (<6) and increased CRT, and C, high MAT (≥6), present different risks for development of macular edema (DME) and proliferative retinopathy (PDR). To test these findings, 212 persons with type 2 diabetes (T2D) and mild nonproliferative retinopathy (NPDR), one eye per person, were followed for five years with annual visits. Of these, 172 completed the follow-up or developed an outcome: PDR or DME (considering both clinically significant macular edema (CSME) and center-involved macular edema (CIME)). Twenty-seven eyes (16%) developed either CSME (14), CIME (10), or PDR (4), with one eye developing both CSME and PDR. Phenotype A showed no association with development of vision-threatening complications. Seven eyes with phenotype B and three with phenotype C developed CIME. Phenotype C showed higher risk for CSME development, with 17.41 odds ratio ( = 0.010), compared with phenotypes A + B. All eyes that developed PDR were classified as phenotype C. Levels of HbA and triglycerides were increased in phenotype C ( < 0.001 and = 0.018, respectively). In conclusion, phenotype C identifies eyes at higher risk for development of CSME and PDR, whereas phenotype A identifies eyes at very low risk for vision-threatening complications.
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http://dx.doi.org/10.3390/jcm9051433DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290313PMC
May 2020

Detection and quantification of the anti-obesity drug celastrol in murine liver and brain.

Neurochem Int 2020 06 6;136:104713. Epub 2020 Mar 6.

Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Research Unit Neurobiology of Diabetes, 85764, Neuherberg, Germany; Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Institute for Diabetes and Obesity, 85764, Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany; Technical University of Munich, Neurobiology of Diabetes, TUM School of Medicine, 81675, Munich, Germany. Electronic address:

Celastrol is a natural pentacyclic triterpene extracted from the roots of Tripterygium wilfordi (thunder god vine). Celastrol was reported as a powerful anti-obesity drug with leptin sensitizing properties that decreases food consumption and mediates body weight loss when administered to diet-induced obese mice at 100 μg/kg body weight. The weight lowering properties of celastrol are likely mediated by the CNS, in particular, by the hypothalamus, but the final proof for the accumulation of celastrol in the brain and hypothalamus remains to be established. Here, we aimed to demonstrate that intraperitoneal celastrol administration at 100 μg/kg can rapidly reach the brain and, in particular, the hypothalamus of mice. We developed and validated a sensitive liquid chromatography mass spectrometry method for the quantitative determination of celastrol in murine tissues, namely liver, brain and hypothalamus. Chow-fed lean mice were randomly assigned to the vehicle vs. celastrol groups, injected with saline or 100 μg/kg body weight of celastrol, and sacrificed 30 min or 120 min post injection. Celastrol was extracted from homogenized tissue using ethyl acetate as organic solvent, and quantified using a matrix-matched calibration curve with glycyrrhetinic acid as internal standard. Liver celastrol concentrations were 32.60 ± 8.21 pg/mg and 40.52 ± 15.6 pg/mg, 30 and 120 min after injection, respectively. We found 4.70 ± 0.31 pg/mg celastrol after 30 min, and 16.22 ± 3.33 pg/mg after 120 min in whole brain lysates, and detectable amounts in the hypothalamus. These results corroborate the validity of our methodology, demonstrate the accumulation of celastrol in the brain of mice injected intraperitoneally with a dose of 100 μg/kg, and confirm the CNS as possible site of action for the weight lowering properties of celastrol.
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http://dx.doi.org/10.1016/j.neuint.2020.104713DOI Listing
June 2020

Randomized clinical trial of five adhesive systems in occlusal restorations: One-year results.

Dent Mater J 2020 Jun 22;39(3):397-406. Epub 2020 Jan 22.

School of Dental Medicine, Lisbon University.

This randomized clinical trial evaluated the efficacy of five different adhesive systems in the restoration of occlusal cavities after one year of function. Two etch-and-rinse (Optibond™FL, Prime&BondNT™) and three self-etch (Clearfil™SE Bond, XenoIII, XenoV) adhesive systems were evaluated on 159 occlusal restorations, incrementally filled with a microhybrid composite resin. Restorations were assessed using the FDI criteria at baseline, 6 months and 1 year. Statistical analysis was performed with Friedman-test and Kruskal-Wallis test (p<0.05). At 1 year, 153 restorations were evaluated. A statistically significant decrease in the number of restorations with marginal adaptation classified as excellent occurred for the self-etch adhesives (p<0.01). Etch-and-rinse adhesives presented better performance than any of the self-etch systems (p<0.01) in terms of marginal adaptation. All cases were considered no less than satisfactory. Marginal adaptation was the most influent parameter on the distinctive performance of the adhesives where etch-and-rinse systems performed significantly better than self-etch systems.
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http://dx.doi.org/10.4012/dmj.2019-011DOI Listing
June 2020

Structural Insight into IAPP-Derived Amyloid Inhibitors and Their Mechanism of Action.

Angew Chem Int Ed Engl 2020 03 28;59(14):5771-5781. Epub 2020 Jan 28.

Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und Umwelt, Institute of Structural Biology, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.

Designed peptides derived from the islet amyloid polypeptide (IAPP) cross-amyloid interaction surface with Aβ (termed interaction surface mimics or ISMs) have been shown to be highly potent inhibitors of Aβ amyloid self-assembly. However, the molecular mechanism of their function is not well understood. Using solution-state and solid-state NMR spectroscopy in combination with ensemble-averaged dynamics simulations and other biophysical methods including TEM, fluorescence spectroscopy and microscopy, and DLS, we characterize ISM structural preferences and interactions. We find that the ISM peptide R3-GI is highly dynamic, can adopt a β-like structure, and oligomerizes into colloid-like assemblies in a process that is reminiscent of liquid-liquid phase separation (LLPS). Our results suggest that such assemblies yield multivalent surfaces for interactions with Aβ40. Sequestration of substrates into these colloid-like structures provides a mechanistic basis for ISM function and the design of novel potent anti-amyloid molecules.
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http://dx.doi.org/10.1002/anie.201914559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7154662PMC
March 2020

Comparison between conventional and computerised methods in the assessment of an occlusal scheme.

J Oral Rehabil 2020 Feb 21;47(2):221-228. Epub 2019 Nov 21.

School of Dentistry, University of Siena, Siena, Italy.

Purpose: In the definition of an occlusal scheme, clinicians should choose between conventional and computerised methods based on a careful appraise of the advantages and limitations. This study aims to assess the correlation between the two approaches in a clinical setting.

Methods: Twenty-four patients were included to compare different methods of occlusal contacts assessment on the posterior surfaces of flat mandibular appliances. In supine position, they were asked to clench with maximum strength, in the maximum intercuspation position with a 24 μm articulating paper positioned between the teeth and the appliance surface. An extra-oral photograph of the marks was taken (total N = 2082). They were visually classified based on a pre-defined scale (ie, conventional assessment) and with ImageJ analysis software (ie, photographic software assessment). Additionally, a computerised occlusal analysis was performed (ie, computerised assessment). Correlation analysis of the data achieved with conventional, photographic and computerised assessments was performed.

Results: Correlation between conventional and computerised assessments was weak (r = .265), whilst it was moderate between conventional and photographic assessments (r = .633), as well as between photographic and computerised assessments (r = .476).

Conclusions: This investigation showed a weak-to-moderate correlation between different methods (ie, conventional, photographic and computerised) to assess occlusal marks. None of the three can actually be considered the standard of reference, but based on their specific features, it can bet suggested that the conventional method may be enough for most clinical purposes, unless otherwise proven.
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http://dx.doi.org/10.1111/joor.12905DOI Listing
February 2020

Immediate versus early loading protocols of titanium-zirconium narrow-diameter implants for mandibular overdentures in edentulous patients: 1-year results from a randomized controlled trial.

Clin Oral Implants Res 2019 Oct 21;30(10):953-961. Epub 2019 Jul 21.

Dentistry Department, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

Objectives: The purpose of this randomized clinical trial was to compare immediate and early loading protocols for mandibular overdentures with two-splinted narrow-diameter implants in thin, non-augmented residual ridge situations.

Material And Methods: Each edentulous patient received two implants in the interforaminal region. If primary stability after implant placement was achieved, patients were randomized either to the immediate (48 hr post-surgery) or the early (2 weeks after surgery) loading group. In prosthetic rehabilitation, a bar prosthetic system with a titanium bar was used. Implant survival, success rates, and radiographic changes at the crestal bone level were evaluated after 1 year, and patient satisfaction was recorded at 1 and 6 months post-surgery.

Results: Twenty-four patients with a mean age of 67 ± 9 years were included. One patient passed away after 11 months due to treatment-independent reasons. In the 24 implants of the immediate loading group, the mean bone level change from surgery/loading to the first-year evaluation was 0.32 ± 0.80 mm (p = .066). Regarding the early group (22 implants), the mean bone level change from loading to 1 year was 0.34 ± 0.69 mm (p = .048). After 1 year, no differences could be detected between groups (p = .91) with a mean difference of 0.02 mm (95% CI: [-0.42, 0.47]). The mean implant survival and success rates were 100% for both groups. Patient satisfaction was high; however, at 6 months, there was a difference between groups regarding the ability to chew.

Conclusions: Both loading protocols for mandibular overdentures supported by two-splinted narrow-diameter implants were successful at the 1-year follow-up.
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http://dx.doi.org/10.1111/clr.13502DOI Listing
October 2019

Polymerization Shrinkage Evaluation of Restorative Resin-Based Composites Using Fiber Bragg Grating Sensors.

Polymers (Basel) 2019 May 11;11(5). Epub 2019 May 11.

Institute of Operative Dentistry, Dentistry Area, Faculty of Medicine, University of Coimbra, Avenida Bissaya Barreto, Blocos de Celas, 3700-075 Coimbra, Portugal.

The purpose of this study was to compare the linear polymerization shrinkage of different restorative resin-based composites (RBCs) using fiber Bragg grating (FBG) sensors. Five RBCs were evaluated: Zirconfill (ZFL); Aura Bulk-Fill (ABF); Tetric N-Ceram Bulk-Fill (TBF); Filtek Bulk-Fill (FBF); and Admira Fusion-Ormocer (ADF). Ten samples per resin were produced in standardized custom-made half-gutter silicone molds. Two optical FBG sensors were used to assess temperature and polymerization shrinkage. Light curing was performed for 40 s and polymerization shrinkage was evaluated at 5, 10, 40, 60, 150, and 300 s. Statistical analysis was accomplished for normal distribution (Shapiro-Wilk, > 0.05). Two-way repeated measures ANOVA with Greenhouse-Geisser correction followed by Bonferroni's post-hoc test was used to analyze the linear shrinkage data ( < 0.05). ZFL showed the highest linear shrinkage and ADF the lowest. Shrinkage increased for all RBCs until 300 s, where significant differences were found between ADF and all other resins ( < 0.05). Among bulk-fill RBCs, TBF showed the lowest shrinkage value, but not statistically different from FBF. The ADF presented lower linear shrinkage than all other RBCs, and restorative bulk-fill composites exhibited an intermediate behavior.
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http://dx.doi.org/10.3390/polym11050859DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6571745PMC
May 2019

Peri-implant marginal bone loss reduction with platform-switching components: 5-Year post-loading results of an equivalence randomized clinical trial.

J Clin Periodontol 2019 06;46(6):678-687

Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

Aim: To compare the clinical performance and marginal bone levels of implants restored with platform-switching (PS) or platform-matching (PM) abutments.

Materials And Methods: Adult patients missing two or more adjacent teeth in the posterior mandible received 2-4 CAMLOG SCREW-LINE implants and were randomly allocated to the PM or PS group, receiving the corresponding prosthetic components from surgery onwards. Implants were conventionally loaded with single cemented crowns. Patients were followed annually for 5 years. Outcome measures were marginal bone level changes, implant survival, performance of the prosthetic components and clinical parameters plaque index, sulcus bleeding index and pocket probing depth.

Results: Thirty-three patients received 72 implants in the PM group, and thirty-five patients received 74 implants in the PS group. Sixty patients attended the final appointment, 31 had received PS components and 29 had received PM components with 65 and 63 implants, respectively. Global survival rate was 96.6% with no differences between groups (p = 0.647). After 5 years of functional loading, PS restored implants presented 0.23mm (95% CI: [0.03, 0.43], p = 0.025) lower marginal bone level changes. The two groups were declared non-equivalent.

Conclusion: Patients requiring implant supported restorations in healed bounded or free end edentulous gaps of the mandible benefit from the use of PS components in terms of peri-implant marginal bone level maintenance, though it may not be clinically noticeable.
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http://dx.doi.org/10.1111/jcpe.13119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594132PMC
June 2019

Influence of implant neck and abutment characteristics on peri-implant tissue health and stability. Oral reconstruction foundation consensus report.

Clin Oral Implants Res 2019 Jun 14;30(6):588-593. Epub 2019 May 14.

Section of Graduate Periodontology, University Complutense, Madrid, Spain.

Objective: The aim of this consensus meeting was to assess the influence of implant neck and abutment characteristics on peri-implant tissue health and stability.

Material And Methods: Group and plenary discussions were based on two systematic reviews focusing on the effect of titanium implants with different collar designs/surface modifications and the abutment material on the stability of marginal bone levels (MBLs), peri-implant health, and survival rates.

Results: The changes in MBLs were not influenced by the abutment material and were also similar at one- and two-piece implants after one year of loading. Rough collar implants improved MBLs in comparison to machined collar implants. Additional modifications of the collar had no beneficial clinical effect on MBLs. Titanium abutments were associated with significantly higher increases in bleeding on probing when compared with zirconia abutments.

Conclusion: MBLs are mainly influenced by the microstructure (i.e., rough surfaced) of the implant neck. Consensus statements and specific recommendations for future research were elaborated during the consensus meeting.
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http://dx.doi.org/10.1111/clr.13439DOI Listing
June 2019

Biocompatibility of a bioceramic silicone-based sealer in subcutaneous tissue.

J Oral Sci 2019 ;61(1):171-177

Institute of Biophysics, Faculty of Medicine, University of Coimbra.

This study evaluated the biocompatibility of a new silicone-based sealer (GuttaFlow Bioseal) in rat subcutaneous tissue and compared the results with those for GuttaFlow2 and AH Plus. Each of 16 Wistar rats received four subcutaneous tissue implants, namely, GuttaFlow Bioseal, GuttaFlow2, AH Plus, and one empty polyethylene tube. Eight rats were euthanized at day 8 and the remaining eight at day 30. Histological sections were stained with haematoxylin and eosin and analysed with a light microscope. Scores were established for inflammatory reaction, macrophage infiltrate, thickness of the fibrous capsule, and vascular changes. Differences between groups were assessed by using the Friedman test with Bonferroni correction. Histological analysis showed that GuttaFlow Bioseal had the lowest inflammatory reaction of all tested sealers at day 8. At day 30, the silicone-based sealers had similar inflammation profiles, but inflammation scores were nonsignificantly higher for AH Plus than for the negative control. The inflammatory reaction decreased from day 8 to day 30 in all sealers. GuttaFlow Bioseal had the most macrophage infiltrate. Under the present experimental conditions, GuttaFlow Bioseal induced limited inflammatory reactions at days 8 and 30, and initial inflammatory reactions to GuttaFlow2 and AH Plus subsided within 30 days. All tested sealers exhibited satisfactory biocompatibility at day 30 after subcutaneous implantation.
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http://dx.doi.org/10.2334/josnusd.18-0145DOI Listing
August 2019

Pulp Temperature Rise Induced by Light-Emitting Diode Light-Curing Units Using an Ex Vivo Model.

Materials (Basel) 2019 Jan 29;12(3). Epub 2019 Jan 29.

Instituto de Telecomunicações, Campus Universitário de Santiago, P-3810-193 Aveiro, Portugal.

The aim of this research was to compare the pulp temperature (PT) rise induced by four light-emitting diode light-curing units (LED LCUs) (Bluephase 20i, Demi Ultra, SPEC 3, and Valo) in different curing modes. Immediately after extraction, the pulp chamber of 11 premolars was accessed from the palatal cervical third of the crown for insertion of fiber Bragg grating (FBG) sensors for temperature measurement and kept in a 37.0° water bath. The teeth were then submitted to a random sequence of curing modes with four irradiations at 30 s intervals. Care was taken to ensure complete pulp temperature reset between curing modes. The curing modes were classified as high-energy (above 80 J/cm²) or low-energy (below 40 J/cm²) according to the total energy density delivered. Statistical analysis was performed with repeated ANOVA measures and Pearson's correlation for the association between energy density and temperature variation. The significance level was set to 0.05. All curing units promoted a statistically significant PT rise (p < 0.01). After four emissions, the PT rise was higher than 5.0 °C for the high-energy curing modes. The low-energy modes induced approximately a 2.5 °C rise. A strong positive correlation was found between energy density and PT increase (R = 0.715; p = 0.01). Exposure of intact premolars to LED LCUs induced significant and cumulative PT rise. Curing modes emitting high energy densities produced higher PT variations. Radiant exposure was positively correlated to PT variation.
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http://dx.doi.org/10.3390/ma12030411DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6384635PMC
January 2019

Cyclic fatigue resistance of three rotary file systems in a dynamic model after immersion in sodium hypochlorite.

Odontology 2019 Jul 12;107(3):324-332. Epub 2018 Dec 12.

Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

To evaluate the effect of immersion in 3% sodium hypochlorite solution in the resistance to cyclic fatigue of three nickel-titanium (NiTi) rotary file systems, ProTaper Next (PTN), Hyflex CM (CM), and Hyflex EDM (EDM), in a mechanical model featuring axial movement. Ninety instruments of three different NiTi rotary file systems, PTN (size 25, 0.06 taper), CM (25, 0.06), and EDM (25/~, variable taper), were randomly divided according to a 3 × 3 factorial design and tested under dynamic immersion in a 3% NaOCl solution (1 or 5 min) or without immersion, making a total of 9 groups (n = 10). Files were tested in an artificial root canal with 45° angle and 5 mm radius apical curvature being submitted to back-and-forth movements until fracture. Statistical analysis was performed using two-way factorial ANOVA with Bonferroni post-hoc tests, at a significance level of 5%. Instruments were evaluated for reliability using a Weilbull approach. Regardless of the immersion treatment, PTN had on average 1200 ± 178 cycles to fracture, CM had 1949 ± 362, and EDM had 5573 ± 853, which was a significantly different (P < 0.01). The NaOCl immersion promoted a significant reduction in the mean number of cycles to fracture (P = 0.01), and was reflected in a significant reduction of the characteristic life of the instruments of the CM end EDM groups. Within this study conditions, EDM instruments performed better to cyclic fatigue followed by CM and then PTN. Immersion in NaOCl decreased the resistance to cyclic fatigue of all tested instruments, but affected more those manufactured from CM wire.
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http://dx.doi.org/10.1007/s10266-018-0401-2DOI Listing
July 2019

Celastrol Promotes Weight Loss in Diet-Induced Obesity by Inhibiting the Protein Tyrosine Phosphatases PTP1B and TCPTP in the Hypothalamus.

J Med Chem 2018 12 7;61(24):11144-11157. Epub 2018 Dec 7.

Institute of Structural Biology , Helmholtz Zentrum München , 85764 Neuherberg , Germany.

Celastrol is a natural pentacyclic triterpene used in traditional Chinese medicine with significant weight-lowering effects. Celastrol-administered mice at 100 μg/kg decrease food consumption and body weight via a leptin-dependent mechanism, yet its molecular targets in this pathway remain elusive. Here, we demonstrate in vivo that celastrol-induced weight loss is largely mediated by the inhibition of leptin negative regulators protein tyrosine phosphatase (PTP) 1B (PTP1B) and T-cell PTP (TCPTP) in the arcuate nucleus (ARC) of the hypothalamus. We show in vitro that celastrol binds reversibly and inhibits noncompetitively PTP1B and TCPTP. NMR data map the binding site to an allosteric site in the catalytic domain that is in proximity of the active site. By using a panel of PTPs implicated in hypothalamic leptin signaling, we show that celastrol additionally inhibited PTEN and SHP2 but had no activity toward other phosphatases of the PTP family. These results suggest that PTP1B and TCPTP in the ARC are essential for celastrol's weight lowering effects in adult obese mice.
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http://dx.doi.org/10.1021/acs.jmedchem.8b01224DOI Listing
December 2018

Titanium dental implants with different collar design and surface modifications: A systematic review on survival rates and marginal bone levels.

Clin Oral Implants Res 2019 Jan 18;30(1):20-48. Epub 2018 Dec 18.

Dentistry Department, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal.

Aim: The aim of this study was to compare clinical and radiographic outcomes of dental implants with different neck characteristics.

Methods: A protocol-oriented search aimed at the question: "In patients subjected to tooth replacement with screw-type dental implants does the modification of the implant neck macro- or microgeometry contribute to the improvement of survival rates and maintenance of the peri-implant marginal bone levels?" Primary outcomes were survival and marginal bone level (MBL) changes evaluated on randomized controlled trials with >10 participants and follow-up >1 year. Risk of bias was evaluated using the Cochrane Collaboration's tool. The review follows the PRISMA statement.

Results: Forty-three studies compared: (a) One- versus two-piece implants (N = 7); (b) Two-piece implants with different neck characteristics (machined and rough collars, microthreads, LASER microtexturing) (N = 21); (c) Two-piece implants with macrogeometry modifications (tapering, back-tapering, and scalloping) (N = 6). One- and two-piece implants showed similar survival (RR = 0.45, 95% CI: [0.12, 1.66], p = 0.23) and MBL changes (WMD = 0.09 mm, 95% CI: [-0.27, 0.45], p = 0.64) at 1-year post-loading. Machined collar implants have higher risk of early failure than rough collar implants (RR = 3.96, 95% CI: [1.12, 13.93], p = 0.03) and 0.43 mm higher bone resorption (95% CI: [0.0, 0.86], p = 0.05). Microthreads (WMD = 0.07 mm, 95% CI: [-0.01, 0.15], p = 0.10) and LASER microtexturing (WMD = 0.15 mm, 95% CI: [-0.35, 0.65], p = 0.56) do not reduce bone resorption. Scalloped implants have 1.26 mm higher resorption (95% CI: [0.72, 2.00], p < 0.001).

Conclusions: One- and two-piece implants have similar survival and MBL changes. Rough collar implants have lower MBL changes than machined collar implants. Additional modifications to rough collars are irrelevant.
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http://dx.doi.org/10.1111/clr.13389DOI Listing
January 2019

The Structure of the SPOP-Pdx1 Interface Reveals Insights into the Phosphorylation-Dependent Binding Regulation.

Structure 2019 02 15;27(2):327-334.e3. Epub 2018 Nov 15.

Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany; Center for Integrated Protein Science Munich at Chair of Biomolecular NMR Spectroscopy, Department Chemie, Technische Universität München, Lichtenbergstrasse 4, Garching 85747, Germany. Electronic address:

Pdx1 is a transcription factor crucial for development and maintenance of a functional pancreas. It regulates insulin expression and glucose homeostasis. SPOP is an E3-ubiquitin ligase adaptor protein that binds Pdx1, thus triggering its ubiquitination and proteasomal degradation. However, the underlying mechanisms are not well understood. Here, we present the crystal structure of the SPOP-Pdx1 complex. We show that Pdx1 residues 223-233 bind to SPOP MATH domain with low micromolar affinity. The interface is extended compared to other SPOP-client proteins. Previously, Pdx1 phosphorylation has been proposed to have a regulatory function. In this respect we show that phosphorylation lowers the affinity of Pdx1 to SPOP by isothermal titration calorimetry and nuclear magnetic resonance data. Our data provide insights into a critical protein-protein interaction that regulates cellular Pdx1 levels by SPOP-mediated decay. A reduction of Pdx1 levels in β cells is linked to apoptosis and considered a hallmark of type 2 diabetes.
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http://dx.doi.org/10.1016/j.str.2018.10.005DOI Listing
February 2019

Fluorescent blood-brain barrier tracing shows intact leptin transport in obese mice.

Int J Obes (Lond) 2019 06 3;43(6):1305-1318. Epub 2018 Oct 3.

Research Unit Neurobiology of Diabetes, Helmholtz Zentrum München, 85764, Neuherberg, Germany.

Background/objectives: Individuals carrying loss-of-function gene mutations for the adipocyte hormone leptin are morbidly obese, but respond favorably to replacement therapy. Recombinant leptin is however largely ineffective for the vast majority of obese individuals due to leptin resistance. One theory underlying leptin resistance is impaired leptin transport across the blood-brain-barrier (BBB). Here, we aim to gain new insights into the mechanisms of leptin BBB transport, and its role in leptin resistance.

Methods: We developed a novel tool for visualizing leptin transport using infrared fluorescently labeled leptin, combined with tissue clearing and light-sheet fluorescence microscopy. We corroborated these data using western blotting.

Results: Using 3D whole brain imaging, we display comparable leptin accumulation in circumventricular organs of lean and obese mice, predominantly in the choroid plexus (CP). Protein quantification revealed comparable leptin levels in microdissected mediobasal hypothalami (MBH) of lean and obese mice (p = 0.99). We further found increased leptin receptor expression in the CP (p = 0.025, p = 0.0002) and a trend toward elevated leptin protein levels in the MBH (p = 0.17, p = 0.078) of obese mice undergoing weight loss interventions by calorie restriction or exendin-4 treatment.

Conclusions: Overall, our findings suggest a crucial role for the CP in controlling the transport of leptin into the cerebrospinal fluid and from there to target areas such as the MBH, potentially mediated via the leptin receptor. Similar leptin levels in circumventricular organs and the MBH of lean and obese mice further suggest intact leptin BBB transport in leptin resistant mice.
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http://dx.doi.org/10.1038/s41366-018-0221-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6760579PMC
June 2019

Celastrol-Induced Weight Loss Is Driven by Hypophagia and Independent From UCP1.

Diabetes 2018 11 28;67(11):2456-2465. Epub 2018 Aug 28.

Research Unit Neurobiology of Diabetes, Helmholtz Zentrum München, Neuherberg, Germany

Celastrol, a plant-derived constituent of traditional Chinese medicine, has been proposed to offer significant potential as an antiobesity drug. However, the molecular mechanism for this activity is unknown. We show that the weight-lowering effects of celastrol are driven by decreased food consumption. Although young Lep mice respond with a decrease in food intake and body weight, adult Lep and Lep mice are unresponsive to celastrol, suggesting that functional leptin signaling in adult mice is required to elicit celastrol's catabolic actions. Protein tyrosine phosphatase 1 (PTP1B), a leptin negative-feedback regulator, has been previously reported to be one of celastrol's targets. However, we found that global PTP1B knockout (KO) and wild-type (WT) mice have comparable weight loss and hypophagia when treated with celastrol. Increased levels of uncoupling protein 1 (UCP1) in subcutaneous white and brown adipose tissue suggest celastrol-induced thermogenesis as a further mechanism. However, diet-induced obese UCP1 WT and KO mice have comparable weight loss upon celastrol treatment, and celastrol treatment has no effect on energy expenditure under ambient housing or thermoneutral conditions. Overall, our results suggest that celastrol-induced weight loss is hypophagia driven and age-dependently mediated by functional leptin signaling. Our data encourage reconsideration of therapeutic antiobesity strategies built on leptin sensitization.
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http://dx.doi.org/10.2337/db18-0146DOI Listing
November 2018

Mutations in PPCS, Encoding Phosphopantothenoylcysteine Synthetase, Cause Autosomal-Recessive Dilated Cardiomyopathy.

Am J Hum Genet 2018 06 10;102(6):1018-1030. Epub 2018 May 10.

Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.

Coenzyme A (CoA) is an essential metabolic cofactor used by around 4% of cellular enzymes. Its role is to carry and transfer acetyl and acyl groups to other molecules. Cells can synthesize CoA de novo from vitamin B5 (pantothenate) through five consecutive enzymatic steps. Phosphopantothenoylcysteine synthetase (PPCS) catalyzes the second step of the pathway during which phosphopantothenate reacts with ATP and cysteine to form phosphopantothenoylcysteine. Inborn errors of CoA biosynthesis have been implicated in neurodegeneration with brain iron accumulation (NBIA), a group of rare neurological disorders characterized by accumulation of iron in the basal ganglia and progressive neurodegeneration. Exome sequencing in five individuals from two unrelated families presenting with dilated cardiomyopathy revealed biallelic mutations in PPCS, linking CoA synthesis with a cardiac phenotype. Studies in yeast and fruit flies confirmed the pathogenicity of identified mutations. Biochemical analysis revealed a decrease in CoA levels in fibroblasts of all affected individuals. CoA biosynthesis can occur with pantethine as a source independent from PPCS, suggesting pantethine as targeted treatment for the affected individuals still alive.
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http://dx.doi.org/10.1016/j.ajhg.2018.03.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5992122PMC
June 2018

miRNome Expression Analysis Reveals New Players on Leprosy Immune Physiopathology.

Front Immunol 2018 9;9:463. Epub 2018 Mar 9.

Laboratório de Genética Humana e Médica, ICB, UFPA, Belém, Brazil.

Leprosy remains as a public health problem and its physiopathology is still not fully understood. MicroRNAs (miRNA) are small RNA non-coding that can interfere with mRNA to regulate gene expression. A few studies using DNA chip microarrays have explored the expression of miRNA in leprosy patients using a predetermined set of genes as targets, providing interesting findings regarding the regulation of immune genes. However, using a predetermined set of genes restricted the possibility of finding new miRNAs that might be involved in different mechanisms of disease. Thus, we examined the miRNome of tuberculoid (TT) and lepromatous (LL) patients using both blood and lesional biopsies from classical leprosy patients (LP) who visited the Dr. Marcello Candia Reference Unit in Sanitary Dermatology in the State of Pará and compared them with healthy subjects. Using a set of tools to correlate significantly differentially expressed miRNAs with their gene targets, we identified possible interactions and networks of miRNAs that might be involved in leprosy immunophysiopathology. Using this approach, we showed that the leprosy miRNA profile in blood is distinct from that in lesional skin as well as that four main groups of genes are the targets of leprosy miRNA: (1) recognition and phagocytosis, with activation of immune effector cells, where the immunosuppressant profile of LL and immunoresponsive profile of TT are clearly affected by miRNA expression; (2) apoptosis, with supportive data for an antiapoptotic leprosy profile based on , and expression; (3) Schwann cells (SCs), demyelination and epithelial-mesenchymal transition (EMT), supporting a role for different developmental or differentiation gene families, such as Sox, Zeb, and Hox; and (4) loss of sensation and neuropathic pain, revealing that , and aquaporin-1 () may be involved in the loss of sensation or leprosy pain, indicating possible new therapeutic targets. Additionally, may also be involved in skin dryness and loss of elasticity, which are well known signs of leprosy but with unrecognized physiopathology. In sum, miRNA expression reveals new aspects of leprosy immunophysiopathology, especially on the regulation of the immune system, apoptosis, SC demyelination, EMT, and neuropathic pain.
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http://dx.doi.org/10.3389/fimmu.2018.00463DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5854644PMC
April 2019

Effect of round curvature of anterior implant-supported zirconia frameworks: finite element analysis and in vitro study using digital image correlation.

Comput Methods Biomech Biomed Engin 2017 Aug 4;20(11):1236-1248. Epub 2017 Jul 4.

c Polytechnic Institute of Coimbra, ISEC-DEM , Coimbra , Portugal.

Two groups of 4-unit zirconia frameworks were produced by CAD/CAM to simulate the restoration of an anterior edentulous gap supported by 2 implant-abutment assemblies. Group 1 comprised straight configuration frameworks and group 2 consisted of arched frameworks. Specimens were made with the same connector cross-section area and were cemented and submitted to static loads. Displacements were captured with two high-speed photographic cameras and analysed with video correlation system. Frameworks and the implant-abutment assembly were scanned and converted to 3DCAD objects by reverse engineering process. A specimen of each group was veneered and the corresponding 3D geometry was similarly obtained after scanning. Numerical models were created from the CAD objects and the FE analysis was performed on the zirconia frameworks and on the FPDs bi-layered with porcelain (veneered frameworks). Displacements were higher for the curved frameworks group, under any load. The predicted displacements correlated well with the experimental values of the two framework groups, but on the straight framework the experimental vertical displacements were superior to those predicted by the FEA. The results showed that the round curvature of zirconia anterior implant-supported FPDs plays a significant role on the deformation/stress of FPDs that cannot be neglected neither in testing nor in simulation and should be considered in the clinical setting.
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http://dx.doi.org/10.1080/10255842.2017.1348501DOI Listing
August 2017
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