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Dental Materials : Official Publication... Jan 2023Different types of direct-placement dental materials are used for the restoration of structure, function and aesthetics of teeth. The aim of this research investigation...
OBJECTIVES
Different types of direct-placement dental materials are used for the restoration of structure, function and aesthetics of teeth. The aim of this research investigation is to determine, through a comparative cradle-to-gate life cycle assessment, the environmental impacts of three direct-placement dental restorative materials (DRMs) and their associated packaging.
METHODS
Three direct-placement dental materials; dental amalgam, resin-based composite (RBC) and glass polyalkenoate cements (GIC) are assessed using primary data from a manufacturer (SDI Limited, Australia). The functional unit consisted of 'one dental restoration' of each restorative system under investigation: 1.14 g of dental amalgam; 0.25 g of RBC (plus the adhesive = 0.10 g); and 0.54 g of GIC. The system boundary per restoration included the raw materials and their associated packaging materials for each DRM together with the processing steps for both the materials and packaging. The environmental impacts were assessed using an Egalitarian approach under the ReCiPe method using Umberto software and the Ecoinvent database. Nine different impact categories were used to compare the environmental performance of these materials.
RESULTS
Dental amalgam had the highest impact across most of the categories, but RBC had the highest Global Warming Potential. The highest sources of the environmental impacts for each restorative material were: Amalgam, derived from material use; RBC, derived from energy use in processing material and packaging material; GIC, derived from material and energy use for packaging.
SIGNIFICANCE
Less intensive energy sources or more sustainable packaging materials can potentially reduce the impacts associated with RBC and GIC thus making them suitable alternatives to dental amalgam.
Topics: Animals; Dental Restoration, Permanent; Dental Amalgam; Dental Materials; Glass Ionomer Cements; Life Cycle Stages; Composite Resins
PubMed: 36428112
DOI: 10.1016/j.dental.2022.11.007 -
Dental Materials : Official Publication... Aug 2022Titanium (Ti) is considered bioinert and is still regarded as the "gold standard" material for dental implants. However, even 'commercial pure' Ti will contain minor...
OBJECTIVE
Titanium (Ti) is considered bioinert and is still regarded as the "gold standard" material for dental implants. However, even 'commercial pure' Ti will contain minor fractions of elemental impurities. Evidence demonstrating the release of Ti ions and particles from 'passive' implant surfaces is increasing and has been attributed to biocorrosion processes which may provoke immunological reactions. However, Ti observed in peri-implant tissues has been shown to be co-located with elements considered impurities in biomedical alloys. Accordingly, this study aimed to quantify the composition of impurities in commercial Ti dental implants.
METHODS
Fifteen commercial titanium dental implant systems were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES).
RESULTS
The elemental composition of implants manufactured from commercially pure grades of Ti, Ti-6Al-4V, and the TiZr alloy (Roxolid) conformed to the respective ISO/ASTM standards or manufacturers´ data (TiZr/Roxolid). However, all implants investigated included exogenous metal contaminants including Ni, Cr, Sb, and Nb to a variable extent. Other contaminants detected in a fraction of implants included As and the radionuclides U-238 and Th-232.
SIGNIFICANCE
Although all Ti implant studies conformed with their standard compositions, potentially allergenic, noxious metals and even radionuclides were detected. Since there are differences in the degree of contamination between the implant systems, a certain impurity fraction seems technically avoidable. The clinical relevance of these findings must be further investigated, and an adaptation of industry standards should be discussed.
Topics: Alloys; Dental Alloys; Dental Implants; Spectrum Analysis; Surface Properties; Titanium; Uranium
PubMed: 35781168
DOI: 10.1016/j.dental.2022.06.028 -
Dental Press Journal of Orthodontics 2021This paper aims to verify the thermodynamic, mechanical and chemical properties of CuNiTi 35ºC commercial wires.
OBJECTIVE
This paper aims to verify the thermodynamic, mechanical and chemical properties of CuNiTi 35ºC commercial wires.
METHODS
Forty pre-contoured copper-nickel-titanium thermodynamic 0.017 x 0.025-in archwires with an Af temperature of 35°C were used. Eight wires from five different manufacturers (American Orthodontics® [G1], Eurodonto® [G2], Morelli® [G3], Ormco® [G4] and Orthometric® [G5]) underwent cross-sectional dimension measurements, tensile tests, SEM-EDS and differential scanning calorimetry (DSC) tests. Parametric tests (One-way ANOVA and Tukey post-test) were used, with a significance level of 5%, and Pearson's correlation coefficient test was performed between the Af and chemical elements of the wires. All sample tests and statistical analyses were double-blinded.
RESULTS
All wires presented standard dimensions (0.017 x 0.025-in) and superelastic behavior, with mean plateau forces of: G1 = 36.49N; G2 = 27.34N; G3 = 19.24 N; G4 = 37.54 N; and G5 = 17.87N. The Af means were: G1 = 29.40°C, G2 = 29.13°C and G3 = 31.43°C, with p>0.05 relative to each other. G4 (32.77°C) and G5 (35.17°C) presented statistically significant differences between each other and among the other groups. All samples presented Ni, Ti, Cu and Al in different concentrations.
CONCLUSIONS
The chemical concentration of the elements that compose the alloy significantly influenced the thermodynamic and mechanical properties.
Topics: Cross-Sectional Studies; Dental Alloys; Elasticity; Materials Testing; Orthodontic Wires; Stress, Mechanical; Titanium
PubMed: 34008740
DOI: 10.1590/2177-6709.26.2.e211945.oar -
British Dental Journal Jun 2020
Topics: Dental Amalgam; Dental Materials; Dental Restoration Failure; Dental Restoration, Permanent
PubMed: 32541712
DOI: 10.1038/s41415-020-1735-z -
Dental Materials Journal Aug 2023Adhesion of the most common dental biofilm bacteria to alloys used in orthodontics in relation to surface characteristics was analyzed. Streptococcus mutans (S. mutans),...
Adhesion of the most common dental biofilm bacteria to alloys used in orthodontics in relation to surface characteristics was analyzed. Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), Veillonella parvula (V. parvula), and Aggregatibacter actinomycetemcomitans (A. actynomicetemcomitans) were incubated for 4 h with nickel-titanium (NiTi) and stainless-steel (SS) wires. The surface roughness and free energy of the alloys, as well as the hydrophobicity of the alloys and bacteria, were assessed. NiTi had higher surface free energy and rougher (p<0.001) and more hydrophilic surfaces than SS (p<0.001). The hydrophobic properties of the bacteria decreased in the following order: V. parvula>S. oralis>S. mutans>A. actynomicetemcomitans. Bacterial adhesion generally increased over time, though this pattern was influenced by the type of alloy and the bacteria present (p<0.001). In a multiple linear regression, the principal predictor of adhesion was bacterial hydrophobicity (p<0.001), followed by time (p<0.001); alloy surface characteristics had a low influence.
Topics: Dental Alloys; Orthodontic Wires; Surface Properties; Orthodontic Appliances; Alloys; Streptococcus mutans; Titanium; Stainless Steel
PubMed: 37271541
DOI: 10.4012/dmj.2022-235 -
Journal of Oral Science 2022This study investigated whether additive manufactured (AM) surfaces inhibit accumulation of bacterial biofilm on the surfaces of Ti-6Al-4V alloy dental implants....
PURPOSE
This study investigated whether additive manufactured (AM) surfaces inhibit accumulation of bacterial biofilm on the surfaces of Ti-6Al-4V alloy dental implants. Bacterial biofilms are thought to cause peri-implant disease, which develops in mucosa surrounding titanium (Ti) and Ti alloy dental implants and can lead to bone loss and implant failure.
METHODS
Accumulation of a Streptococcus mutans (ATCC 25175) biofilm on Ti-6Al-4V alloy was compared in relation to fabrication method, ie, AM using electron beam melting (EBM) or laser beam melting (LBM). Conventional lost-wax casting was used as positive control, and Teflon was used as negative control. Biofilm accumulation on the alloys and negative control (each n = 10) was conducted at 37°C under anaerobic conditions. After 4 h, the number of metabolically active S. mutans bacteria adhering to the alloy was determined with a bioluminescence assay.
RESULTS
The quantitative roughness values of the specimens, before exposure to bacteria, ranked EBM > LBM > cast > Teflon.
CONCLUSION
The amount of biofilm accumulation on the investigated AM metals and cast metal controls did not significantly differ.
Topics: Alloys; Biofilms; Dental Alloys; Titanium
PubMed: 35370181
DOI: 10.2334/josnusd.21-0521 -
Bundesgesundheitsblatt,... Jul 2021Dental amalgam has been successfully used for the restoration of carious lesions for more than 180 years. It is clinically characterized by high longevity and low... (Review)
Review
Dental amalgam has been successfully used for the restoration of carious lesions for more than 180 years. It is clinically characterized by high longevity and low technique sensitivity. For decades, dental amalgam has been discussed in the public, especially due to its roughly 50% mercury content. Since the Minamata Convention was published in 2013 with the primary goal of reducing the anthropogenic mercury release into the environment, the previously muted amalgam discussion has received fresh impetus. Another considerable disadvantage of amalgam is its silver/greyish color, which simply no longer matches patients' esthetic demands.The present paper describes the basic problems with amalgam against the background of multiple biological, clinical, and health policy factors. Possible consequences of the Minamata Convention concerning legal regulations as well as the use of dental biomaterials and therefore also relating to the future national healthcare system are discussed. Finally, possible amalgam alternatives and the urgent need for biomedical research towards restorative dentistry are presented, embedded into the crucial question of whether we are actually conducting the correct debate.
Topics: Dental Amalgam; Germany; Health Policy; Humans; Mercury
PubMed: 34143251
DOI: 10.1007/s00103-021-03355-4 -
Materials (Basel, Switzerland) Dec 2022Titanium (Ti) alloys used for narrow dental implants usually contain aluminum (Al) and vanadium (V) for improved resistance. However, those elements are linked to...
Titanium (Ti) alloys used for narrow dental implants usually contain aluminum (Al) and vanadium (V) for improved resistance. However, those elements are linked to possible cytotoxic effects. Thus, this study evaluated the biomechanical behavior of narrow dental implants made with Al- and V-free Ti alloys by the finite element method. A virtual model of a partially edentulous maxilla received single implants (diameter: 2.7 and 2.9 mm; length: 10 mm) at the upper lateral incisor area, with respective abutments and porcelain-fused-to-metal crowns. Simulations were performed for each implant diameter and the following eight alloys (and elastic moduli): (1) Ti-6Al-4V (control; 110 GPa), (2) Ti-35Nb-5Sn-6Mo-3Zr (85 GPa), (3) Ti-13Nb-13Zr (77 GPa), (4) Ti-15Zr (113 GPa), (5) Ti-8Fe-5Ta (120 GPa), (6) Ti-26.88Fe-4Ta (175 GPa), (7) TNTZ-2Fe-0.4O (107 GPa), and (8) TNTZ-2Fe-0.7O (109 GPa). The implants received a labially directed total static load of 100 N at a 45° angle relative to their long axis. Parameters for analysis included the maximum and minimum principal stresses for bone, and von Mises equivalent stress for implants and abutments. Ti-26.88Fe-4Ta reaches the lowest maximum (57 MPa) and minimum (125 MPa) principal stress values, whereas Ti-35Nb-5Sn-6Mo-3Zr (183 MPa) and Ti-13Nb-13Zr (191 MPa) models result in the highest principal stresses (the 2.7 mm model surpasses the threshold for bone overload). Implant diameters affect von Mises stresses more than the constituent alloys. It can be concluded that the narrow implants made of the Ti-26.88Fe-4Ta alloy have the most favorable biomechanical behavior, mostly by mitigating stress on peri-implant bone.
PubMed: 36556709
DOI: 10.3390/ma15248903 -
BioMed Research International 2017The objective of the study is to characterise the mechanical properties of Ti-15Zr binary alloy dental implants and to describe their biomechanical behaviour as well as...
The objective of the study is to characterise the mechanical properties of Ti-15Zr binary alloy dental implants and to describe their biomechanical behaviour as well as their osseointegration capacity compared with the conventional Ti-6Al-4V (TAV) alloy implants. The mechanical properties of Ti-15Zr binary alloy were characterised using Roxolid© implants (Straumann, Basel, Switzerland) via ultrasound. Their biomechanical behaviour was described via finite element analysis. Their osseointegration capacity was compared via an study performed on 12 adult rabbits. Young's modulus of the Roxolid© implant was around 103 GPa, and the Poisson coefficient was around 0.33. There were no significant differences in terms of Von Mises stress values at the implant and bone level between both alloys. Regarding deformation, the highest value was observed for Ti-15Zr implant, and the lowest value was observed for the cortical bone surrounding TAV implant, with no deformation differences at the bone level between both alloys. Histological analysis of the implants inserted in rabbits demonstrated higher BIC percentage for Ti-15Zr implants at 3 and 6 weeks. Ti-15Zr alloy showed elastic properties and biomechanical behaviours similar to TAV alloy, although Ti-15Zr implant had a greater BIC percentage after 3 and 6 weeks of osseointegration.
Topics: Alloys; Animals; Dental Implants; Finite Element Analysis; Humans; Materials Testing; Rabbits; Stress, Mechanical
PubMed: 29318142
DOI: 10.1155/2017/2785863 -
The Journal of Advanced Prosthodontics Jun 2021The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after...
PURPOSE
The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after wear testing and the degree of wear for each dental alloy was assessed.
MATERIALS AND METHODS
Cast crowns of three metal alloys (Co-Cr, gold, and Ni-Cr alloys) opposing smooth-surface monolithic zirconia were used. The Vickers microhardness of the ingot (which did not undergo wear testing) and the cast crown before and after wear testing were measured for each alloy. Two-way ANOVA and Scheffé tests were used to compare the measured hardness values. Moreover, the Pearson correlation coefficient was used to evaluate the relationship between the surface hardness and the wear of the cast crown (α=.05).
RESULTS
There was no significant difference in the hardness before and after wear testing for the gold alloy (>.05); however, the hardness of the worn surface of the cast crown increased compared to that of the cast crown before the wear tests of Ni-Cr and Co-Cr alloys (<.05). Furthermore, there was no correlation between the wear and hardness of the cast crown before and after wear testing for all three metal alloys (>.05).
CONCLUSION
There was a significant difference in hardness between dental alloys under the same conditions. No correlation existed between the surface hardness of the cast crown before and after wear testing and the wear of the cast crown.
PubMed: 34234922
DOI: 10.4047/jap.2021.13.3.127