Influence of antibacterial surface treatment on dental implants on cell viability: A systematic review.

There is no consensus in the literature about the best non-cytotoxic antibacterial surface treatment for dental implants. Critically evaluate the existing literature and answer the question: "which surface treatment for dental implants made of titanium and its alloys has the greatest non-cytotoxic antibacterial activity for osteoblastic cells?" This systematic review was registered in the Open Science Framework (osf.io/8fq6p) and followed the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols. The search strategy was applied to four databases. Articles were selected that evaluated in both studies the properties of 1) antibacterial activity and 2) cytotoxicity on osteoblastic cells of titanium and their alloy dental implants when treated superficially. Systematic reviews, book chapters, observational studies, case reports, articles that studied non-dental implants, and articles that evaluated only the development of surface treatment were excluded. The Joanna Briggs Institute, a quasi-experimental study assessment tool, was adapted to assess the risk of bias. The search strategy found 1178 articles in the databases after removing duplicates in EndNote Web, resulting in 1011 articles to be evaluated by title and abstract, of which 21 were selected for full reading, of which 12 were included by eligibility criteria, and nine were excluded. Quantitative synthesis could not be performed due to the heterogeneity of the data (surface treatment, antibacterial assay, bacteria strain, cell viability assay, and cell type). Risk of bias assessment showed that ten studies were classified as low risk and two studies as moderate risk. The evaluated literature allowed us to conclude that: 1) The literature surveyed did not allow answering the question due to the heterogeneity of the studies; 2) Ten of the 12 studies evaluated presented surface treatments with non-cytotoxic antibacterial activity; 3) Adding nanomaterials, QPEI, BG, and CS, reduce the chances of bacterial resistance by controlling their adhesion by electrical forces.

Mechanical performance of 3-dimensionally printed resins compared with conventional and milled resins for the manufacture of occlusal devices: A systematic review.

STATEMENT OF PROBLEM: Digital methods for manufacturing occlusal devices provide advantages over conventional techniques, but information about the mechanical properties of 3-dimensionally (3D) printed resins is scarce. PURPOSE: The purpose of this systematic review was to evaluate the literature to determine whether 3D-printed resins for occlusal devices present satisfactory mechanical performance when compared with milled and conventional heat polymerized and autopolymerized resins. MATERIAL AND METHODS: This systematic review followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol and was registered in the Open Science Framework. The search strategy was applied without restriction of time and language to Embase, PubMed, Scopus, Science Direct, and Web of Science databases, and to the nonpeer-reviewed literature in ProQuest and Google Scholar. The selection process was conducted independently in 2 stages by 2 reviewers according to the eligibility criteria. The risk of bias was analyzed by using a checklist of important parameters to be considered. The systematic review considered the population, intervention, comparison, outcome, studies (PICOS) format, where population was resins for 3D printing of occlusal devices, intervention was inherent characteristics of the resin, comparison was conventional heat polymerized, autopolymerized, and milled resins, outcome was mechanical performance, and studies were in vitro experimental studies. RESULTS: A total of 1430 articles were found with the search strategy. After removing 182 duplicates found in Rayyan, the title and abstract of 1248 articles were evaluated, of which 37 articles were screened from the databases, 23 were selected for full reading, and 6 met the eligibility criteria and were included in this review; 1 had a low risk of bias and 5 had a moderate risk. An additional search of the reference list of included articles did not result in the inclusion of any articles. A quantitative meta-analysis could not be performed because of the heterogeneity of the included studies regarding the type of resin used and the method for evaluating mechanical performance. CONCLUSIONS: Resins for 3D printing had satisfactory mechanical performance for interocclusal devices when compared with conventional heat polymerized and autopolymerized resins, except for hardness. Milled resins were better than 3D-printed resins in hardness, wear resistance, flexural strength, flexural modulus, and fracture resistance when printing angle and thickness were not considered. Further development is needed in terms of printing techniques and chemical composition, as they are important for optimal mechanical properties and clinical performance.

Influence of surface electric charge of Ti implants on osteoblastic interaction: A systematic review.

Objective: A critical analysis of the existing literature to answer "What is the influence of electrical charge of titanium alloys in the electrical interaction with osteoblastic cells for osseointegration?". Design: This systematic review followed PRISMA. The personalized search strategy was applied in PubMed, Science Direct, Embase, and Scopus databases, furthermore, in the grey literature in the Google Scholar and ProQuest. The selection process was carried out in two stages independently by two reviewers according to the eligibility criteria. The risk of bias was also analyzed. Results: When applying the search strategy, 306 articles were found, after removing duplicates 277 were analyzed by title and abstract, of which 33 were selected for full reading, of which 10 met the eligibility criteria. And one was included from the additional literature search. Of these, all had a low risk of bias. Conclusions: 1. The phenomenon of osseointegration is complex and, independent of the superficial electrical charge of the implant, it may occur. To understand osseointegration, attention must be paid to the synergistic action of the electrical potential; chemical composition, intrinsic to the alloy and from surface treatment; and topography, which will determine the speed of adhesion, proliferation, and osteoblast differentiation. 2. The presence of Ca2+ deposited on the surface acts as a driving force for biomineralization that induces osteoblastic attraction and differentiation; 3. For a better understanding of the current literature, more studies are needed to describe the osteogenic regulation process through protein mediation; 4. Topography and chemical composition act as decisive parameters for cell viability independent of the attractive electrical charge.

Influence of the roughness of dental implants obtained by additive manufacturing on osteoblastic adhesion and proliferation: A systematic review.

Objective: Critically analyzed the existing literature to answer the question "What is the influence of roughness of surfaces for dental implants obtained by additive manufacturing compared to machined on osteoblastic cell adhesion and proliferation?" Design: This systematic review followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered in the Open Science Framework. The personalized search strategy was applied to Embase, Pub Med, Scopus, and Science Direct databases and Google Scholar and ProQuest grey literature. The selection process was carried out in two stages independently by two reviewers according to the eligibility criteria. The risk of bias was analyzed using a checklist of important parameters to be considered. Results: When applying the search strategy on databases 223 articles were found, after removing the duplicates, 171 were analyzed by title and abstract of which 25 were selected for full reading, of these, 6 met the eligibility criteria. 2 studies were included from the reference list totaling 8 articles included in this systematic review and none were included from the Grey Literature. 7 had a low risk of bias and 1 moderate. Conclusions: 1) Roughness is a property that must be analyzed and correlated with the chemical composition, intrinsic to the alloy and resulting from the surface treatment; morphology of topographic peaks and valleys; printing technique and its parameters; 2) Need for more studies on the biomolecular level to elucidate the mechanism by which the roughness and the morphology of topographical peaks and valleys descriptive of roughness influence osteoblastic adhesion and proliferation.

Digital versus conventional workflow for the fabrication of physical casts for fixed prosthodontics: A systematic review of accuracy.

STATEMENT OF PROBLEM: A consensus on the accuracy of additively manufactured casts in comparison with those fabricated by using conventional techniques for fixed dental prostheses is lacking. PURPOSE: The purpose of this systematic review was to determine the accuracy of additively manufactured casts for tooth- or implant-supported fixed dental prostheses in comparison with that of gypsum casts. MATERIAL AND METHODS: This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered with the International Prospective Register of Systematic Reviews (PROSPERO) database (CDR42020161006). Eight databases were searched in December 2019 and updated in September 2020. Studies evaluating the dimensional accuracy of additively manufactured casts for fixed dental prostheses in comparison with that of gypsum casts were included. An adapted checklist for reporting in vitro studies (Checklist for Reporting In vitro Studies guidelines) was used to assess the risk of bias. RESULTS: Eight studies evaluating tooth-supported fixed dental prosthesis casts and 7 studies evaluating implant-supported fixed dental prosthesis casts were eligible for this review. Gypsum casts showed greater accuracy (trueness and precision) in most studies, although additively manufactured casts also yielded highly precise data. One study was associated with a low risk of bias, 9 with a moderate risk of bias, and 5 with a high risk of bias. CONCLUSIONS: In vitro studies showed that additively manufactured casts and gypsum casts share similar accuracy within the acceptable range for the fabrication of casts. The quality of scanned data, additive manufacture technology, printing settings, and postprocessing procedures plays an essential role in the accuracy of additively manufactured casts. Clinical studies are required to confirm these findings.

Influence of chemical composition on cell viability on titanium surfaces: A systematic review.

STATEMENT OF PROBLEM: A consensus on which dental implant alloy and surface treatment provide the best cell viability is unclear. PURPOSE: The purpose of this systematic review was to provide information on the influence of surface and intrinsic titanium alloy chemical components on cell viability. MATERIAL AND METHODS: The PubMed, LILACS, COCHRANE library, and Science Direct databases were electronically searched for the terms dental implants AND titanium AND cytotoxicity. Inclusion criteria were research articles that studied titanium or its alloys for chemical composition and cell viability and were published in English between 1999 and 2019. Articles that did not study titanium and its alloys, articles with nondental or biomedical implants, and articles that were not found in their entirety were excluded. RESULTS: A total of 1226 articles selected by title or abstract according to the inclusion and exclusion criteria resulted in 51 articles that were reduced to 27 after reading in full. The treatments analyzed were arc fusion, electron beam physical deposition, plasma electrolytic oxidation, coating addition, micro arc oxidation, anodization, thermochemical process, BMP-2 immobilization, pressure-assisted sintering, and alkali heat treatment. CONCLUSIONS: The evaluated literature did not allow a determination of the best surface treatment for cell viability because of the heterogeneity of the studies regarding the type of alloy, cell used in the MTT assay, study, and implant purpose (biomedical or dental). The cytotoxic effect of chemical components was dependent on dose, time, size, temperature, and cell type. The niobium, tantalum, zirconium, and molybdenum elements have been most often added in the development of less toxic Ti alloys with lower modulus of elasticity and increased strength.

Comparative analysis of corrosion resistance between beta titanium and Ti-6Al-4V alloys: A systematic review.

BACKGROUND: The knowledge of the electrochemical property (corrosion resistance) of beta titanium alloys compared to Ti-6Al-4 V for implants is relevant because of the potential cytotoxic effects that the released ions could cause to long-term health. OBJECTIVES: The objective of this systematic review was to seek information on the electrochemical properties (corrosion resistance) of beta titanium alloys compared to Ti-6Al-4 V since the awareness of the electrochemical behavior of the implant surface in the medium is essential for the best indication of the alloys or compositional changes, which may promote benefits to bone-implant interaction in all areas that this procedure is required. METHODS: The PubMed, LILACS, COCHRANE Library, and Science Direct databases were electronically searched for the terms: dental implants AND beta-titanium AND Ti-6Al-4 V AND electrochemical technics. The inclusion criteria were research articles that studied beta-titanium compared to Ti-6Al-4 V using electrochemical techniques in electrolytes of chemical composition similar to body fluid, published in English, between 2000 and 2020. Articles that did not compare the corrosion resistance of these alloys in electrolytes similar to body fluids were excluded. RESULTS: A total of 189 articles were restored and selected by title and/or abstract according to the inclusion and exclusion criteria, which resulted in 15 articles that were reduced to 8 after read in full. The studies in vitro evaluated the corrosion resistance in electrolytes Hank, Ringer, SBF, and 0.9 % NaCl, between beta titanium alloys, obtained by arc fusion or bars stock, and Ti-6Al-4 V, for dental or biomedical implants submitted to surface treatments by heat treatment, plasma electrolytic oxidation (PEO), alkaline treatment, and thermomechanical. CONCLUSION: The evaluated literature allowed to determine that 1) The oxides Nb2O 5, Ta2O 5, and ZrO2 have higher stability and protection quality than that of TiO2 modified by the oxides of Al and V; 2) A higher modulus of elasticity of the Ti-6Al-4 V alloy favors protection against corrosion by maintaining a thicker and more firmly adhered oxide layer; 3) The increase in the thickness of the Ti alloys superficial layer contributes to the improvement of the corrosion resistance.