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Titanium Alloys for Dental Implants: A Review

  • Bluefield Centre for Biomaterials, London

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The topic of titanium alloys for dental implants has been reviewed. The basis of the review was a search using PubMed, with the large number of references identified being reduced to a manageable number by concentrating on more recent articles and reports of biocompatibility and of implant durability. Implants made mainly from titanium have been used for the fabrication of dental implants since around 1981. The main alloys are so-called commercially pure titanium (cpTi) and Ti-6Al-4V, both of which give clinical success rates of up to 99% at 10 years. Both alloys are biocompatible in contact with bone and the gingival tissues, and are capable of undergoing osseointegration. Investigations of novel titanium alloys developed for orthopaedics show that they offer few advantages as dental implants. The main findings of this review are that the alloys cpTi and Ti-6Al-4V are highly satisfactory materials, and that there is little scope for improvement as far as dentistry is concerned. The conclusion is that these materials will continue to be used for dental implants well into the foreseeable future.
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Titanium Alloys for Dental Implants: A Review
John W. Nicholson
Dental Materials Unit, Bart’s and the London Institute of Dentistry, Queen Mary University of London, Mile End
Road, London E1 4NS, UK and Bluefield Centre for Biomaterials, 67-68 Hatton Garden, London EC1N 8JY, UK; or
Received: 14 May 2020; Accepted: 10 June 2020; Published: 15 June 2020
The topic of titanium alloys for dental implants has been reviewed. The basis of the
review was a search using PubMed, with the large number of references identified being reduced
to a manageable number by concentrating on more recent articles and reports of biocompatibility
and of implant durability. Implants made mainly from titanium have been used for the fabrication
of dental implants since around 1981. The main alloys are so-called commercially pure titanium
(cpTi) and Ti-6Al-4V, both of which give clinical success rates of up to 99% at 10 years. Both alloys
are biocompatible in contact with bone and the gingival tissues, and are capable of undergoing
osseointegration. Investigations of novel titanium alloys developed for orthopaedics show that they
oer few advantages as dental implants. The main findings of this review are that the alloys cpTi
and Ti-6Al-4V are highly satisfactory materials, and that there is little scope for improvement as far
as dentistry is concerned. The conclusion is that these materials will continue to be used for dental
implants well into the foreseeable future.
titanium; alloys; dentistry; corrosion; biocompatibility; osseointegration; clinical outcomes
1. Introduction
The topic of titanium alloys for use as dental implants has been studied. A search was carried out
through PubMed based on the key words titanium,dental and alloys, with further refinements through
the keywords osseointegration,biocompatibility,corrosion and novel alloys. This gave an initial number of
7700 references, and even following the refinements, there were several hundred relevant references
identified. The main selection from these was to concentrate on papers published in the past five
years, with an emphasis on experimental studies of biological properties and on reviews of clinical
performance. Key papers published before this have been included where they provide information
on current practice and illustrate how the clinical use of titanium-based implants has evolved.
2. Titanium-Based Dental Implants
Since the introduction of titanium alloys for the purpose around 1981, there has been a marked
increase in the use of dental implants to replace lost teeth in patients [
]. The most common reason
for tooth loss in adults is periodontal disease, though other causes, such as trauma and developmental
defects, may also lead to it [
]. Modern titanium-based dental implants have high success rates and are
only rarely associated with complications or failure [1].
Implants involve the use of a metal support that is in direct contact with the bone. Titanium is used
in alloys to fabricate dental implants due to its good mechanical properties, low density (4.5 g/cm
and good bone-contact biocompatibility. The main alloy used is so-called commercially pure titanium,
cpTi [
]. This metal is available in four grades numbered 1 to 4, according to the purity and the
processing oxygen content [
]. These grades dier in corrosion resistance, ductility and strength, and it
is grade 4 cp-Ti, with the highest oxygen content (around 0.4%) and best overall mechanical strength
Prosthesis 2020,2, 100–116; doi:10.3390/prosthesis2020011
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(see Table 1), that is most widely used for dental implants [
]. There is also the alloy Ti-6Al-4V,
sometimes called grade 5 titanium. Its composition is also shown in Table 1, where it can be seen that
the numbers in the formula refer to the approximate percentage composition by mass.
Grade 5 titanium is widely used in orthopaedics [
]. This is because of its superior strength
and lower Young’s modulus. However, it may also be used in dentistry, and the use of this alloy
has been shown to be acceptable biologically [
]. However, this alloy releases both aluminium and
vanadium [
], both of which are capable of causing biological problems. Aluminium interferes with
bone mineralization [
], leading to structural deficiencies, and vanadium is both cytotoxic and capable
of causing type IV (allergic) reactions [
]. To have these adverse eects, they both need to be present
in the tissues at reasonable concentrations, and levels released from this alloy are well below those
needed to produce toxic eects [
]. Amounts released are also below the average nutritional uptake
of these ions. Studies have confirmed that this alloy will undergo satisfactory osseointegration [
especially when treated to enhance the oxide layer on the surface [10].
Table 1. Composition and properties of titanium alloys used as implants.
cpTi Grade 1 cpTi Grade 2 cpTi Grade 3 cpTi Grade 4 Ti6Al4V
Titanium ca 99% ca 99% ca 99% ca 99% 90%
Oxygen 0.18% 0.25% 0.35% 0.4% 0.2% max
Iron 0.2% 0.2% 0.2% 0.3% 0.25%
Nitrogen 0.03% 0.03% 0.05% 0.05% -
Hydrogen 0.15% 0.15% 0.15% 0.15% -
Carbon 0.1% 0.1% 0.1% 0.1% -
UTS/MPa 240 340 450 550 900
strength/MPa 170 275 380 480 850
Elongation at
failure/%25 20 18 15 10
The design of modern implants usually involves a screw thread through which the metal alloy
component becomes anchored within the bone of the mandible or maxilla. A smooth section of metal
protrudes through the soft tissue of the gingiva and supports the artificial tooth, which is typically
made from a ceramic material [
]. Partly as a result of this design, care has to be taken in selecting
the patient to receive an implant. There has to be enough bone in the aected part of the mandible or
maxilla to secure and support the implant [
], and the site must also have a good supply of blood.
This means that the patient must be free of circulatory disorders, and should also be a non-smoker.
This latter factor is important because tobacco smoke has the eect of making the blood capillaries
to contract, causing them to reduce the blood supply to the soft tissues [
]. Lastly, patients have to
maintain good levels of oral hygiene. This is to reduce the possibility of infection in the tissues adjacent
to the implant [15].
When implants are used in dentistry, they should be handled carefully to make sure that they do
not become contaminated. The surfaces should be kept scrupulously clean and, in order to achieve this,
precautions are advised, such as manipulating the implant with titanium-tipped forceps and avoiding
touching any of the surfaces [
]. Despite these precautions, surface analysis using X-ray photoelectron
spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF SIMS) has shown that
surfaces attract considerable amounts of contamination during handling [
]. This contamination is
typically organic, and shows high levels of carbon with some oxygen. Detecting titanium in these
surfaces was often not possible [
]. However, despite this, the long-term integrity of titanium implants
and their ability to osseointegrate are good. Survival rates of at least 89% over 10 years have been
reported, and figures have typically exceeded this figure by considerable amounts. These studies have
involved several hundred implants, with survival rates in the range 97–99% [
] (Table 2) showing
just how successful these devices are.
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Table 2. Recent clinical outcomes of titanium-based dental implants.
Follow-Up Time/Years Pretreatment Survival Rate/% Reference
10 Sandblast and acid-etch 98.8 [13]
10 Sandblast and acid-etch 99.7 [14]
20 Plasma-sprayed with Ti 89.5 [15]
10 Anodised 96.5 [16]
9–12 Oxidised 97.1 [17]
Another possible source of contamination that should be considered is bacterial contamination
during surgical placement of the dental implant [
]. This type of contamination can occur when
bacteria that are present naturally within the oral tissues colonise the sub-gingival surface of the
implant. This may then lead to infection and impairment of the healing process, with the process
of osseointegration being compromised [
]. A systematic review [
] considered this topic and
addressed the question of whether such contamination influences the success of dental implants to any
great extent, but concluded that there was insucient evidence to draw firm conclusions.
2.1. Titanium and its Alloys
Titanium is a transition metal that is able to form solid solutions with elements with similarly
sized atoms. In the solid state, it has hexagonal close packed geometry up to 882.5
C, known as the
structure. Above this temperature, solid titanium changes to a body centred cubic form known as the
structure, until it melts at 1688
C [
]. In alloys, titanium occurs in a variety of forms, which can
be pure
or pure
, or combinations of the two [
]. The alloying elements with titanium are either
-stabilisers, such aluminium, or
-stabilisers, such as vanadium, iron, nickel and cobalt. Oxygen is an
-stabiliser. There are also a few metallic elements, such as zirconium, which have no influence on the
stability of either the phases.
In making implants, titanium alloys that are either completely or mainly
are preferred, because
they have superior corrosion resistance. The processing conditions can be selected to favour the
micro-structure, and this also aects the mechanical properties (strength, ductility, fatigue resistance
and fracture toughness). Data on phase structures of titanium alloys and their physical properties are
given in Table 3.
Table 3. Properties of alloys of titanium for dental implants.
Alloy Micro-Structure Elastic Modulus/GPa Yield Strength/MPa Density/g cm3
cpTi Grade 1 α102 170 4.5
cpTi Grade 2 α102 275 4.5
cpTi Grade 3 α102 380 4.5
cpTi Grade 4 α104 483 4.5
Ti-6A1-4V α+β113 795 4.4
2.2. Surface Chemistry
For both of the main alloys used to make implantable devices, namely commercially pure titanium,
cpTi, and Ti-6A1-4V, the surfaces are mainly composed of the oxide TiO
]. This oxide layer is
4–6 nm thick and also contains hydroxyl groups in addition to the oxide. The exact composition of
the surface is important in promoting the adhesion of osteoblasts and the oxide layer tends to have
favourable biological properties. However, the body still recognizes it as a foreign body, so that under
some circumstances it may cause fibrosis to develop around the implant [28].
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The detailed structure of the TiO
film on titanium surfaces varies with the composition of
the alloy, and also with its processing history (see Table 4). Titanium implants usually have their
surfaces modified after their initial fabrication in order to ensure that oxidation is uniform and that
any contamination is removed [
]. The resulting surfaces have improved biological characteristics,
and promote the processes of cell adhesion and proliferation, both of which contribute to bone
bonding [30,31].
Table 4. Possible surface treatments of titanium alloy implants.
Treatment type Surface Change Eect
Machining Alter surface roughness. Cleans surface.
Grinding Improves adhesion
Acid treatment Modifies oxide layer. Improves biocompatibility in all cases.
Alkali treatment Forms sodium titanate gel. Improves biocompatibility in all cases.
Hydrogen peroxide Dense inner oxide layer,
porous outer layer.
Anodic oxidation Increase thickness of TiO2
Plasma spray Deposits coating such as
Flame spray Deposits coating such as
Improves wear and corrosion resistance.
Ion beam implantation Modifies surface composition. Enhances biological properties.
The surface of the alloy Ti-6A1-4V has quite a dierent composition from those of the various
grades of cpTi [
]. As well as TiO
, this alloy contains both aluminium and vanadium in the surface
layers, usually as the appropriate metal oxides. This alters the metal–cell interactions, and is why
dental implants are more often made from cpTi.
The surface finish and roughness are also important features of titanium implants because they
influence the quality of the interaction with the bone. Surface roughness can be quantified by the
terms S
, the arithmetic mean of the roughness area from the mean plane, and S
, the density of peaks
per unit of area [
]. Surfaces of implants can be divided into four dierent categories, depending
on the surface roughness based on the value of S
as follows: smooth (S
m); minimally
rough (S
between 0.5–1.0
m); moderately rough (S
between 1.0–2.0
m); rough (S
m) [
In general, it is moderately rough surfaces that give the best results [34,35].
3. Biocompatibility of Titanium for Dental Implants
Corrosion behaviour is one of the most important factors that influence the biocompatibility of
metal implants. This is because the metal ions that corrosion liberates can cause various adverse eects.
These can be both to the tissue immediately surrounding the implant and systemically, where there
may be allergic reactions. The latter, so called type IV reactions, do not depend on the dose, so are not
aected by the rate of corrosion. They occur simply because corrosion causes metal ions to be released.
On the other hand, tissue reactions adjacent to the implant do depend on the dose, so that in
turn, they are aected by the rate of corrosion. Titanium alloys have good corrosion resistance [
though this may be altered by the presence of proteins such as albumin, and consequently there can be
Prosthesis 2020,2104
an increase in the amount of titanium released into the tissues [
]. Evaluating how much titanium
might be released and how damaging it might be is dicult, because a number of dierent animal
models have been used in the published studies, and also dierent approaches to implantation and
implant retrieval have been used. In some animals, e.g., baboons and rabbits, titanium levels in the
tissues did not change when implants were present [
], whereas in other animals, e.g., rats, elevated
concentrations of titanium were found in the spleen and there was observable degeneration of the
liver [38].
The two most widely used titanium alloys, cpTi and Ti-6A1-4V can both readily osseointegrate.
Osseointegration is considered to occur when direct contact develops between the living bone and the
metal, without any intervening layer of fibrous capsule. Both cpTi and Ti-6A1-4V are bioactive and
able to promote the formation of bone in direct contact with the metal surface. This is dierent from
the biomedical alloys 316L stainless steel and cobalt-chromium, where living bone is unable to make
close contact with the metal surface.
The interfacial zone between the titanium alloy implant and living bone is critical in the
development of osseointegration. This region, which is thin (20–50 nm), is the region into which
growth factors are released from the bone cells, and this initiates the steps that result in bone
formation [
]. The initial step is deposition of proteins from the blood plasma onto the surface
oxide layer. This is followed by the formation of a fibrin matrix, a structure that acts as a scaold
for osteoblasts (the bone-forming cells) [
]. Supported in this way, the osteoblasts lay down bone,
which expands to fill the interfacial region, so that it grows right up against the implant surface,
causing the implant to become osseointegrated. The important eect of proper osseointegration is that
the implant is held rigidly, unlike the case where fibrous capsule forms, and in dentistry this provides
a firm anchor for the prosthetic device.
The oxide layer on the surface plays a major role in the success of osseointegration. Thicker and
rougher oxide coatings encourage osseointegration to occur reliably and quickly, at least over the
shorter term [
]. The oxide coating also has the eect of passivating the metal, so that corrosion is
inhibited and the release of titanium ions is minimized [43].
Cells of various types interact with the surfaces of titanium alloys. These alloys have surfaces
with the appropriate surface energy and charge, and the first thing they do is to attract a layer of
proteins [
]. A sequence of proteins is deposited, eventually leading to the deposition of extracellular
matrix proteins [
], and these stimulate the osteoblasts, which then become attached [
]. As has
already been mentioned, cells prefer rough, porous surfaces with an irregular morphology [
of the type that can be readily produced on implantable devices.
When dental implants are used, titanium levels in the blood [
] and the serum [
] are raised.
The increases are minor but significant, and indicate that titanium is leached from these devices.
Entering the blood stream indicates that the titanium released is capable of being transported round
the whole body. However, in most patients, it has no toxic eects on any of the body’s tissues [
]. In
a very small number, there may be adverse systemic eects in the form of type IV reactions [
However, these are very rare and aect only a very small number of patients. In most patients, titanium
is completely acceptable within the body and its presence causes no adverse eects.
The widely used alloys cpTi and Ti-6Al-4V have excellent properties for use as dental implants.
There has been discussion in the literature as to which is better for use as dental implants [
]. Generally,
cpTi is slightly favoured [
], but results of
in vitro
studies have usually found that Ti-6Al-4V is superior.
What can be said of both alloys is that they undergo osseointegration and are highly biocompatible
with bone and oral tissues. They show minimal corrosion and cause few systematic eects in a small
minority of patients. Biomechanically they are fit for purpose and clinical survival rates are high over
many years of service. Consequently, the scope for improving them is slight. Nevertheless, there has
been some interest in developing new alloys for use as dental implants. The main approach has been to
eliminate the elements with the potential to cause harm biologically, mainly vanadium, and to reduce
Prosthesis 2020,2105
the modulus so that it more closely matches that of bone [
]. The various approaches that have been
tried are considered in the remaining sections of this paper.
In order for an alloy to be considered biocompatible and for it to undergo osseointegration, it must
be tested in a variety of ways. One important preliminary test is for cytotoxicity. Like most metals,
titanium alloys in the bulk are not toxic, but when they corrode and form ions, or wear and generate
particles, they may become so [
]. In order to measure the cytotoxicity of metal ions or wear debris,
the standard method is the MTT assay, as described in the appropriate International Standard for the
biological evaluation of medical devices [55].
The test procedure involves a colorimetric test for mitochondrial activity of cultured cells using
the reagent MTT (3-(4,5-dimethylthiazol-2-yl diphenyltetrazolium bromide). When cells have active
mitochondria, they reduce MTT to a formazan that is both insoluble and strongly coloured [
The colour that develops, a deep purple, has a maximum absorbance at a wavelength of 570 nm and
measuring the absorbance at this wavelength enables the number of viable cells in a sample to be
quantified directly [56,57].
MTT assays are typically carried out in 96-well plates, which allows high throughput. The reagent is
dissolved in physiologically balanced solutions and added to cells in culture, typically at concentrations
in the range 0.2 to 0.5 mg/cm
. They are incubated for short periods of time (1–4 hours), then the
amount of the purple formazan produced is determined from absorbance measurements at 570 nm in
a calibrated colorimeter. Healthy cells with high mitochondrial activity produce the deepest purple
colour [56,57].
Testing in this way has been carried out on numerous titanium alloys in order to determine their
cytotoxicity [
]. For example, Ti-6Al-4V has been shown to have cytotoxicity comparable
to that of pure titanium metal, despite the presence of both aluminium and vanadium [
Other alloying elements have also been shown to be acceptable using the MTT assay, including iron [
molybdenum [
], niobium [
], zirconium [
] and tantalum [
]. Copper, by contrast, has been
found to increase the cytotoxicity markedly [
]. Studies have confirmed that low cytotoxicity correlates
with cells being able to adhere to metal surfaces and remain functional [
]. Low cytotoxicity is thus
the foundation of the other desirable biological properties of titanium alloys, namely biocompatibility
and osseointegration.
4. Binary Alloys of Titanium
A large number of metals have been alloyed with titanium, typically as the minor component,
to prepare alloys for possible use as dental implants. These include niobium [
], silver [
gold [
], manganese [
] and zirconium [
]. Some alloying elements, such as silver or
chromium [
] probably reduce the biocompatibility of the alloy. This is because they are likely to
release either silver or chromium, both of which are known to have adverse biological eects [
On the other hand, several of the elements used, such as niobium [
] and zirconium [
], are benign in
terms of their biological eects, so the resulting alloys are more promising for use as implant materials.
A considerable amount of work has been done on binary alloys of titanium with zirconium.
These have varied widely in composition, from 10% by mass zirconium [
], to up to 50% by mass
zirconium [
] and, in one study, 70% by mass zirconium [
]. Zirconium has a number of advantages
as alloying metal for this application. It readily forms alloys with titanium, and it strongly resists
corrosion [
], which means that it releases only trace amounts of metal ions into the body. Despite this,
Ti-Zr alloys show inferior osseointegration with living bone [
]. On the other hand, studies aimed
specifically at dental applications have shown the alloys to have mechanical properties comparable
with cpTi [
], and, with suitable surface preparation, good biocompatibility and improved osteoblast
adhesion compared with cpTi [
]. Both of these findings suggest that Ti-Zr alloys may have some
advantages when used for dental implants.
Niobium has also been studied in binary alloys with titanium [
], though it has been more widely
used in ternary alloys, such as Ti-6Al-7Nb [
]. Binary alloys containing minor amounts of niobium
Prosthesis 2020,2106
(less than 10% by mass) have been found to have good mechanical properties. Their hardness, yield
strengths and tensile strengths typically exceed those of cpTi [
]. There is also evidence that their
corrosion behaviour is improved [
]. Despite this improvement, experimental studies have shown
that human fibroblasts grow slower and less extensively in Ti-Nb alloys than on cpTi [84].
Manganese is an element that is generally acceptable biologically [
], and for that reason it has
been studied in binary alloys with titanium. Levels have been relatively low, i.e., 8% or 12% by
mass, and the eects have been beneficial. Hardness and density both increase when manganese is
present [
]. Cell adhesion appears to be enhanced in the alloy [
], but cell viability adjacent to these
alloys was slightly inferior that that around a cpTi implant [71].
The noble metals silver [
], gold [
], platinum and palladium [
] have been used to prepare
binary biomedical alloys with titanium. Not surprisingly, these alloys were all found to have improved
corrosion resistance compared with cpTi, so might be expected to show superior biocompatibility
with bone and soft tissues [
]. However, this has only been confirmed experimentally for the
Ti-Ag system [
]. Such alloys are inevitably expensive [
], and it is doubtful whether the marginal
improvement in corrosion resistance justifies their high cost.
There have been some studies reported on binary alloys of indium with titanium [
Like zirconium, indium has also been used in multi-component alloys, such as Ti-In-Nb-Ta, where the
alloy showed good bioactivity [
]. In binary alloys, indium imparted increased strength and also
corrosion resistance that was at least as good as cpTi [
]. This, in turn, led to the alloy having good
biocompatibility in cell cultures.
So far, these studies of binary alloys suggest that there are several possible pairings with titanium
that are less susceptible to corrosion, and because of this, show greater biocompatibility with cells.
However, the only binary alloy that has really been oered substantial improvements so far is Ti-Zr,
and there are ongoing studies on this material as a possible alloy for fabricating dental implants.
5. Multi-Component Alloys of Titanium
A range of alloys containing at least three metals has been studied as possible implant materials,
including for dentistry. They are listed in Table 5. The additional components are typically transition
metals, though tin has also been included in a few experimental studies. In some instances, changes in
composition resulted in the inclusion of additional amounts of oxygen [
], though the oxygen
concentration has not typically been aected by changes in metal composition.
Table 5. Multi-component alloys studied as implant materials.
Composition Reference Reference
Okazaki et al, Biomaterials,1998,19, 1197. [92]
Ti-15Zr-4Nb-4Ta-4Mo Okazaki et al, Biomaterials,1998,19, 1197. [92]
Ti-16Nb-13Ta-4Mo Niinomi, et al, Mater. Sci. Eng. A., 1999,263, 193. [93]
Ti-15Sn-4Nb-2Ta-0.2Pd Okazaki et al, Biomaterials,1998,19, 1197. [92]
Ti-15Sn-4Nb-0.2Pd-0.2O Okazaki et al, Biomaterials,1998,19, 1197. [92]
Ti-15Zr-10Cr Wang et al, Mater. Sci. Eng. C., 2015,51, 148. [94]
Ti-13Nb-13Zr Correa et al, Mater. Sci. Eng. C., 2014,34, 354. [95]
Ti-29Nb-13Ta-4Mo Niinomi et al, Mater. Sci. Eng. A., 1999,263, 193. [93]
Ti-29Nb-13Ta-6Sn Niinomi et al, Mater. Sci. Eng. A., 1999,263, 193. [93]
Ti-29Nb-13Ta-2Sn Niinomi et al, Mater. Sci. Eng. A., 1999,263, 193. [93]
Ti-19Zr-10Nb-1Fe Xue et al, Mater. Sci. Eng. C., 2015,50, 179–186. [96]
Raducanu et al, J. Mech. Behav. Biomed. Mater.,
,4, 1421.
Ti-29Nb-13Ta-7Zr Correa et al, Mater. Sci. Eng. C., 2014,34, 354. [95]
Raducanu et al, J. Mech. Behav. Biomed. Mater.,
,4, 1421.
Prosthesis 2020,2107
Elements, such as tin, iron and palladium, have been used only in a relatively few studies, whereas
others, such as zirconium, niobium and tantalum, have been studied by several groups of workers
and results with them appear in a number of publications. Niobium and tantalum both stabilize the
phase of titanium [
], so their presence eectively replaces vanadium in Ti-6Al-4V and in the
case of either metal, does so with an improvement in the biological acceptability of the resulting alloy.
Alloys that are fabricated with niobium and/or tantalum contain both the
phases. The presence
of the
phase is particularly desirable in biomedical grades of titanium because it confers low elastic
modulus and increased corrosion resistance [93,96], both of which result in superior performance.
One multi-component alloy of titanium with niobium that has been widely studied for bone-contact
applications is Ti-6Al-7Nb. In particular, it has become increasingly used to fabricate dental
. It is an
alloy and was originally developed for orthopaedics, and has
superior mechanical properties compared with cpTi [
]. It is also resistant to corrosion [
] and
when corrosion does occur, its biological properties are acceptable, mainly because of the absence of
vanadium [103,104].
In terms of the biological responses it evokes, Ti-6Al-7Nb resembles cpTi. Human gingival
fibroblasts have been found to adhere, spread and proliferate to similar extents on both alloys [
Short-term implantation of Ti-6Al-7Nb has been shown to provoke a brief inflammatory response
that was similar to that associated with cpTi, but subsequently to lead to highly satisfactory biological
outcomes [
]. There is also some evidence that Ti-6Al-7Nb promotes better spreading of
osteoblast-like cells than cpTi [
] and that its ability to undergo osseointegration in animal models
(dogs) is good [109].
Electrochemical studies have been carried out to determine the corrosion behaviour of Ti-6Al-7Nb.
In Hank’s solution, a composition designed to mimic physiological fluids from the body, Ti-6Al-7Nb
showed high corrosion resistance and good stability [
]. Mechanical strength and wear resistance
were also found to be good when Ti-6Al-7Nb was prepared as castings [
], which confirmed the
promise of this alloy for use as dental prostheses.
Overall, Ti-6Al-7Nb has been shown to have particularly good properties, both physical and
biological, for use in dentistry. However, it does not seem to be particularly widely used for this
purpose, as far as it is possible to judge from the literature. Most studies concern cpTi, with some
considering Ti-6Al-4V, and relatively few explicitly state that they use the alloy Ti-6Al-7Nb. Given the
experimental results that implants made from this alloy have shown, this may change in the future.
6. Surface Modification of Titanium Alloys
As has been described already, the surface of the implant is critical for ensuring the necessary
osseointegration of dental implants. As well as relying on the natural oxide coating that is found on
titanium alloy surfaces, various approaches to altering these surfaces have been studied. These range
from roughening, through either acid or alkaline treatment, typically being followed by heating, to
coating with an inorganic material such as hydroxyapatite or diamond-like carbon. These approaches
will now be considered briefly. As with much of the work on titanium alloys, many of the studies have
been aimed at improving materials for orthopaedics, and modifying surfaces specifically for dental
implants has been studied much less.
Roughening the surface by some additional processing step has been found to be eective in
improving the ability of titanium alloys to undergo osseointegration. This roughening also leads to
higher survival rates for dental implants [
]. For example, one study compared the survival rates
of implants with rough and smooth surfaces, and showed that the survival rates at 20 to 27 months
was 98% for the rough surface but only 81% for the smooth one [
]. The roughening process has
been shown to alter the surface energy, and this improves the deposition of protein, which in turn
enhances the attachment of cells and improves osseointegration of the implant [113].
Surfaces can be roughened by various methods. One involves blasting with particulates,
possibly sand, but also alumina, corundum of hydroxyapatite [
]. Another involves etching with
Prosthesis 2020,2108
mineral acids such as aqueous HCl and H
of appropriate concentrations [
]. These substances
can be used as the only treatment, or can be combined with sandblasting to produce surfaces of
diering degrees of roughness [
]. The combined roughening approach has been shown to be
especially successful in producing surfaces that develop close early contact with bone following
implantation [
], though over the longer term (six weeks or more) there was no advantage in using
this technique, and bone contact with the implant surface was no longer improved by it having
been done.
Acid-etching to roughen surfaces is not the only chemical method that has been used. Alkaline
treatment has also been used to alter surfaces, though this tends not alter surface roughness but to
aect surface charge. As an example, it has been found that treatment of titanium alloy with strongly
concentrated NaOH solution results in a sodium titanate surface that interacts more actively with bone
and more readily promotes growth [
]. Alkaline treatment results in a negatively charged surface that
rapidly adsorbs calcium ions from body fluids [
In vitro
studies using simulated body fluid
(SBF) have shown that the initial adsorption of Ca
ions is quickly followed by deposition of phosphate
ions and the eventual formation of hydroxyapatite [
]. The sequential nature of this deposition
process has been confirmed by X-ray photoelectron spectroscopy [
]. However, despite this
success, such alkaline treatments have mainly been considered for orthopaedic devices [
] rather
than for dental implants.
One other method that has been widely studied for modifying implant surfaces is anodic
oxidation. This is an accelerated electrochemical process that leads to the formation of a substantial
oxide coating on the metal surface [
]. The development of such a thick oxide coating on titanium
implants may improve corrosion resistance [
], as well as enhancing the bonding of bone cells to the
surface [125,126].
A coating formed by anodic oxidation depends on a number of features of the electrochemical
process, including anode voltage and the composition of the electrolyte solution. High voltages tend to
produce thicker and more porous oxide coatings than lower voltages [
]. Various types of electrolyte
solution can be used, such as solutions of sulfuric acid, phosphoric acid or ethanoic acid, as well
as neutral salts, or even alkaline solutions, such as aqueous calcium or sodium hydroxide [
and a variety of thicknesses and crystal structures of titanium dioxide have been produced. Despite
these successes, it is not clear to what extent such approaches are used on practical implant devices.
Indeed, there have been no reports on the long-term eects of these observed improvements in cell
attachment and corrosion resistance, and with the present level of knowledge, it is not clear that
surfaces prepared in this way oer any clinical advantages over oxide finishes that occur naturally on
titanium alloy implants.
The most obvious substance to use to coat implants is hydroxyapatite, and this has been used
successfully in orthopaedics to develop so-called cementless prostheses [
]. Hydroxyapatite coating
has also been used for dental implants [
] with the aim of improving the rate of osseointegration [
The hope is to shorten treatment times, especially for patients whose bone quality is poor [133,134].
Early results with coatings applied to dental implants in the 1990s were not good for various reasons,
including detachment of the hydroxyapatite coating and dissolution of the detached HA [
However, recently coating methods have been improved, and techniques such as ion-sputtering or
thermal plasma treatment have been used [
]. This has resulted in more durable coatings that
adhere better to the titanium substrate and therefore have greater promise for clinical use. This has led
to renewed interest in coating dental implants. The demands of specific locations suggest that coated
implants might be necessary in order to ensure optimum clinical results. For example, hydroxyapatite
screw implants have been recommended for the anterior maxilla and the posterior mandible [
However, uncertainty remains about the long-term durability of these coatings remains, and although
research is continuing on hydroxyapatite-coated dental prostheses, they are used on only a minority of
clinical implants in current practice [
]. The high bioactivity of titanium alloy surfaces, together with
the ability to undergo osseointegration reliably means that any improvement from hydroxyapatite
Prosthesis 2020,2109
coatings would have to be substantial, and current coatings have not yet shown the necessary levels
of improvement.
Another material that has been used to coat dental implants, at least for experimental study,
is diamond-like carbon (DLC) [
]. This is an amorphous material that has high inherent
biocompatibility with bone, and has been applied using chemical vapour deposition onto heated
cpTi abutment screws [
]. The application technique can be varied somewhat, and can include
electrodeposition [
]. It should ideally include the deposition of an intermediate layer, such as
amorphous silicon, to promote adhesion of DLC to the substrate [
]. The aim has been to produce
surfaces of improved corrosion resistance and enhanced biocompatibility, and there is experimental
evidence that success with these aspects can be achieved
in vitro
]. However, despite this
promise, this approach has not yet had any impact on clinical practice, and DLC-coated dental implants
are not yet being used in patients.
7. Conclusions
This paper has described the reasons that titanium alloys are the materials of choice for the
fabrication of dental implants. The principal alloys in practical use are commercially pure titanium and
Ti-6Al-4V. The mechanical properties of the latter are better, but the slight concern over the biological
eects of the very minor amounts of aluminium and vanadium that they release means that cpTi is the
more widely used of the two. Despite these concerns, there is a large amount of experimental evidence
to show that both alloys have good bioactivity and the ability to osseointegrate. Additionally, there are
few, if any, accounts of adverse eects arising from release of aluminium and/or vanadium from dental
implants, probably because amounts released are so low.
The result of the excellent biological and mechanical properties of titanium alloys is that success
rates with dental implants made of these materials are very high. Various studies are described which
show that failure rates over considerable time periods are extremely low. Depending on the details
of the study and the materials used, at least 89% and typically 97–99% of implants survive for over
10 years. Given these results, the scope for improving either the materials or the clinical procedures
is limited. For this reason, the two well-established alloys of titanium continue to be used for the
overwhelming majority of implants used in dentistry, and this use seems likely to continue for the
foreseeable future.
Funding: This work received no external funding.
Conflicts of Interest: The author declares no conflict of interest.
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... Elemental titanium (Ti) and Ti alloys have been used as materials for dental and orthopedic implants since the early 1950s due to their stable chemical properties, good mechanical characteristics, low density, and good bone-contact biocompatibility [1][2][3]. However, most Ti-based implants can fail due to the poor antibacterial activity and osteoinductive properties. ...
... In this work, Mg-Fe LDH films were deposited on the titanium surface of real dental implants via the hydrothermal treatment method. Specifically, the titanium disks that were used for the LDH growth were made of titanium alloy, usually named Ti 6Al-4V [2], an alpha-beta alloy with a content of 6% Al and 4% V. It is one of the most commonly used titanium alloys and exhibits a very good combination of corrosion resistance, toughness, and strength. ...
... The passivation of the metal substrate is also a result of the presence of the oxide layer, which thus inhibits corrosion and minimizes the release of Ti ions [2]. The Mg-Fe LDH-modified titanium surface demonstrated the capability to increase the pH in an aqueous environment, thus forming an alkaline microenvironment that is more suitable for osteoblast growth and osseointegration [22]. ...
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Layered double hydroxides (LDHs) consist of two-dimensional, positively charged lamel-lar structures with the ability to host various anions in the interlayer spaces, which grants them unique properties and tunable characteristics. LDHs, a class of versatile inorganic compounds, have recently emerged as promising candidates for enhancing osseointegration. A suitable alkaline microenvironment is thought to be beneficial for stimulating osteoblasts' differentiation (responsible for bone matrix formation) while suppressing osteoclast generation (responsible for bone matrix disintegration). LDHs are prone to adjusting their alkalinity and thus offering us the chance to study how pH affects cellular behavior. LDHs can indeed modulate the local pH, inflammatory responses, and oxidative stress levels, factors that profoundly influence the behavior of osteogenic cells and their interactions with the implant surface. Herein, we deposited Mg-Fe LDH films on titanium substrates for dental implants. The modified Ti substrates was more alkaline in comparison to the bare ones, with a pH higher than 8 after hydrolysis in an aqueous environment.
... These implants lacked adequate fitting and often caused peri-implantitis by implant movements. 1,6 In the past decade, the concept of subperiosteal implants has reemerged with the evolving digital technologies used in dental and prosthesis fabrications. Techniques involving computed tomography (CT) and CBCT scans have played a significant role in this resurgence. ...
... Since the 1980s, dental endosseous implants have become one of the most common replacements for teeth. 1 However, the need for adequate bone quality and quantity is not always met. Restoring a resorbed alveolar ridge through dental rehabilitation, irrespective of its origin, necessitates a complex and challenging treatment path. ...
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Key Clinical Message Subperiosteal implants might be the future first‐line treatment in patients with compromised alveolar ridges, although the use of proper techniques and pre‐surgical imaging is required to ensure treatment success. Abstract Severe bone loss puts the success of endosseous implants at risk. This technical report aims to introduce the subperiosteal implants (SPIs) created through additive manufacturing. A case study is presented, outlining the process and strategies employed to fully restore a maxillary structure using a customized subperiosteal implant. The patient, who had previously faced disappointment with traditional endosseous implants, received a customized SPI. A detailed 3‐year follow‐up is also provided. The design of the subperiosteal framework and abutments is based on digital records of the patient's jaw structure and a radiographic stent during occlusion. This ensures optimal placement within the dental arch. The implant and abutments are then three‐dimensional (3D) printed using a titanium alloy, while a provisional denture is 3D‐printed using polymer materials. SPIs offer a viable alternative for individuals with severe jaw bone degeneration, as demonstrated in this report detailing their application in complete maxillary restoration. This patient‐specific, prosthesis‐driven approach avoids the need for bone grafting and enables immediate functional recovery through a single surgical procedure.
... Titanium has been utilized in the fabrication of dental implants since approximately 1981 [13]. According to the osseointegration concept, Brånemark first demonstrated how titanium implants induce bone integration and discovered that the titanium oxide (TiO 2 ) layer might be responsible for establishing direct bone-implant contact [14]. ...
... Grade IV CpTi is the most commonly utilized variety due to its high oxygen content (0.4%) and, thus, excellent mechanical strength. The alloy Ti-6Al-4V, often known as grade V titanium, is widely used in orthopedics because of its superior strength and lower Young's modulus [13]. However, aluminum (Al) and vanadium (V) may affect bone mineralization and type IV allergic reactions, respectively [65]. ...
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Abstract: Titanium has been the material of choice for dental implant fixtures due to its exceptional qualities, such as its excellent balance of rigidity and stiffness. Since zirconia is a soft-tissue-friendly material and caters to esthetic demands, it is an alternative to titanium for use in implants. Nevertheless , bone density plays a vital role in determining the material and design of implants. Compromised bone density leads to both early and late implant failures due to a lack of implant stability. Therefore, this narrative review aims to investigate the influence of implant material/design and surgical technique on bone density from both biomechanical and biological standpoints. Relevant articles were included for analysis. Dental implant materials can be fabricated from titanium, zirconia, and PEEK. In terms of mechanical and biological aspects, titanium is still the gold standard for dental implant materials. Additionally, the macro-and microgeometry of dental implants play a role in determining and planning the appropriate treatment because it can enhance the mechanical stress transmitted to the bone tissue. Under low-density conditions, a conical titanium implant design, longer length, large diameter, reverse buttress with self-tapping, small thread pitch, and deep thread depth are recommended. Implant material, implant design, surgical techniques, and bone density are pivotal factors affecting the success rates of dental implant placement in low-density bone. Further study is required to find the optimal implant material for a clinical setting's bone state. Citation: Khaohoen, A.; Sornsuwan, T.; Chaijareenont, P.; Poovarodom, P.; Rungsiyakull, C.; Rungsiyakull, P. Biomaterials and Clinical Application of Dental Implants in Relation to Bone Density-A Narrative Review. J. Clin. Med. 2023, 12, 6924. https://doi.
... The eligibility of Materials for use in biomedical implant applications is determined by such properties as biocompatibility, biofunctionality, bioadhesion, and corrosion resistance. 1 The main metallic biomaterials are stainless steel, cobalt alloys, titanium (Ti), and Ti alloys. 2 Titanium and Ti alloys are excellent choices of materials in biomedical applications because of their high specific strength and their biocompatibility. 3 Because a persistent and inert oxide layer spontaneously forms on the surface of commercially pure titanium (CPTi) when it is exposed to oxidizing environments, Ti alloys and CPTi are the preferred alloys for making Ti implants. ...
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Introduction: Several techniques have been used to modify the surface of commercially pure titanium (CPTi) implants to improve osseointegration using lasers, sandblasts, sandblasts with acid etching, and other modalities. For implant-osseointegration, surface features like the chemical composition of a surface, topography, and surface energy are essential. The present comparative study aimed to compare the impact of Er, Cr: YSGG laser, sandblasting, and acid etching implant surface modifications on the surface topography, roughness, and element chemical composition of the Ti dental implant. Methods: Thirty CPTi dental implants were divided into three groups according to the surface modification (n=10 for each group): Group A: Sandblasting with acid etching (SLActive), group B: Sandblasting, and Group C: Er,Cr: YSGG laser surface modifications. The modified surfaces were analyzed using scanning electron microscopy (SEM), profilometer, and energy dispersive x-ray spectrometry (EDS). Results: One-way analysis of variance (ANOVA) showed that there were significant differences in the mean values of average roughness (Ra) of the three groups (P<0.05). Tukey’s post hoc test showed that the average roughness (Ra) of laser-surface modification (group C) of the implant had the highest mean value (2.30 µm) among the different groups, while sandblasted surface modification (group B) of the implant had the lowest mean value (1.39 µm). The SLActive (group A) sandblast with acid etching had a mean value of 1.63 µm. SEM analysis showed that significantly modified surface topographies and different element concentrations were found within all modified groups. Conclusion: The Er, Cr: YSGG laser irradiation increased the implant surface roughness value after implant surface modification, compared to sandblasts and sandblasts with acid etching application. The observations for the SEM-EDS analysis revealed several elements with different concentrations, which were affected by the physical–chemical characteristics of the surface modification techniques. The SEM analysis showed a significant modification in implant surface topographies of the tested groups.
... Zirconia is used as a crown material for its many benefits, including its high strength, good biocompatibility, aesthetics, minimally invasive behaviour, corrosion resistance, bioinertness, and long lifespan (Duraccio et al. 2015;Ferreira et al. 2020;Shi et al. 2022). Due to the excellent biocompatibility of titanium (Nicholson 2020), an alloy of Ti-6Al-4V is used for dental screws and abutment (Mini et al. 2016). The material properties of the bones and implant components that were used in this study are listed in Table 1. ...
The article aims to design and develop a topology-optimized endosseous cuspid tooth implant of the maxilla region. The manuscript presents a numerical analysis of the resulting von Mises stresses and effective strain resulting in the topology-optimized implant with occlusal loading of 110 N. Solid Isotropic Material with Penalization (SIMP) method is employed for topology optimization and four different models, namely model-1, model-2, model-3, and model-4, are developed based on volume reduction rates of 8%, 16%, 24%, and 32%, respectively. FEA results highlight that the maximum stress and strain in the screw increases with volume reduction rates. The comparative analyses of the resulting stresses in the compact and cancellous bone along with the strain in the screw led to the conclusion that model-1, model-2, and model-3 resulted in moderate stresses on compact and cancellous bone compared to the original model of the implant. However, the screw and bones are subjected to maximum stress and strain in the model-4. The study concludes that model-2, with 16% reduced volume and 14.2% reduced mass as compared to the original implant, may be considered as the optimized design of the model. The resulting model offers a significant reduction in the weight and volume with a minor increase in effective stress and strain without negatively impacting the functionality and bio-mechanical performance of the implant. The optimized dental implant prototype is also fabricated as a proof of concept by the Fused Deposition Modelling process. ARTICLE HISTORY
... Since this healing takes time, the process may take several months. In this case report, we present a case of titanium dental implant surgery [8][9][10][11] for a patient in her fifties ( Fig. 1 and 2). ...
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The topography and composition of dental implant surfaces directly impact mesenchymal cell adhesion, proliferation, and differentiation, crucial aspects of achieving osseointegration. However, cell adhesion to biomaterials is considered a key step that drives cell proliferation and differentiation. The aim of this study was to characterize characterize the topography and composition of commercial titanium dental implants manufactured with different surface treatments (two sandblasted/acid-etched (SLA) (INNO Implants, Busan, Republic of Korea; BioHorizonsTM, Oceanside, CA, USA) and two calcium phosphate (CaP) treated (Biounite®, Berazategui, Argentina; Zimmer Biomet, Inc., Warsaw, IN, USA)) and to investigate their influence on the process of cell adhesion in vitro. A smooth surface implant (Zimmer Biomet, Inc.) was used as a control. For that, high-resolution methodologies such as scanning electron microscopy (SEM), X-ray dispersive spectroscopy (EDX), laser scanning confocal microscopy (LSCM), and atomic force microscopy (AFM) were employed. Protein adsorption and retromolar gingival mesenchymal stem cells (GMSCs) adhesion to the implant surfaces were evaluated after 48 h. The adherent cells were examined by SEM and LSCM for morphologic and quantitative analyses. ANOVA and Tukey tests (α = 0.05) were employed to determine statistical significance. SEM revealed that INNO, BioHorizonsTM, and Zimmer implants have an irregular surface, whereas Biounite® has a regular topography consisting of an ordered pattern. EDX confirmed a calcium and phosphate layer on the Biounite® and Zimmer surfaces, and AFM exhibited different roughness parameters. Protein adsorption and cell adhesion were detected on all the implant surfaces studied. However, the Biounite® implant with CaP and regular topography showed the highest protein adsorption capacity and density of adherent GMSCs. Although the Zimmer implant also had a CaP treatment, protein and cell adhesion levels were lower than those observed with Biounite®. Our findings indicated that the surface regularity of the implants is a more determinant factor in the cell adhesion process than the CaP treatment. A regular, nanostructured, hydrophilic, and moderately rough topography generates a higher protein adsorption capacity and thus promotes more efficient cell adhesion.
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There have been several attempts to improve the cellular and molecular interactions at the tissue–implant interface. Here, the biocompatibility of titanium-based implants (e.g., Grade 2 Titanium alloy (Ti-40) and titanium–niobium alloy (Ti-Nb)) has been assessed using different cellular and molecular examinations. Cell culture experiments were performed on three substrates: Ti-40, Ti-Nb, and tissue culture polystyrene as control. Cells number and growth rate were assessed by cell counting in various days and cell morphology was monitored using microscopic observations. The evaluation of cells’ behavior on the surface of the implants paves the way for designing appropriate biomaterials for orthopedic and dental applications. It was observed that the cell growth rate on the control sample was relatively higher than that of the Ti-40 and Ti-Nb samples because of the coarse surface of the titanium-based materials. On the other hand, the final cell population was higher for titanium-based implants; this difference was attributed to the growth pattern, in which cells were not monolayered on the surface. Collagen I was not observed, while collagen III was secreted. Furthermore, interleukin (IL)-6 and vascular endothelial growth factor (VEGF) secretion were enhanced, and IL-8 secretion decreased. Moreover, various types of cells can be utilized with a series of substrates to unfold the cell behavior mechanism and cell–substrate interaction.
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Titanium (Ti) and its alloys are widely used for medical and dental implant devices—artificial joints, bone fixators, spinal fixators, dental implant, etc. —because they show excellent corrosion resistance and good hard-tissue compatibility (bone formation and bone bonding ability). Osseointegration is the first requirement of the interface structure between titanium and bone tissue. This concept of osseointegration was immediately spread to dental-materials researchers worldwide to show the advantages of titanium as an implant material compared with other metals. Since the concept of osseointegration was developed, the cause of osseointegration has been actively investigated. The surface chemical state, adsorption characteristics of protein, and bone tissue formation process have also been evaluated. To accelerate osseointegration, roughened and porous surfaces are effective. HA and TiO2 coatings prepared by plasma spray and an electrochemical technique, as well as alkalinization of the surface, are also effective to improve hard-tissue compatibility. Various immobilization techniques for biofunctional molecules have been developed for bone formation and prevention of platelet and bacteria adhesion. These techniques make it possible to apply Ti to a scaffold of tissue engineering. The elucidation of the mechanism of the excellent biocompatibility of Ti can provide a shorter way to develop optimal surfaces. This review should enhance the understanding of the properties and biocompatibility of Ti and highlight the significance of surface treatment.
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Background Titanium is a commonly used inert bio-implant material within the medical and dental fields. Although the use of titanium is thought to be safe with a high success rate, in some cases, there are rare reports of problems caused by titanium. In most of these problematic reports, only individual reports are dominant and comprehensive reporting has not been performed. This comprehensive article has been prepared to review the toxicity of titanium materials within the medical and dental fields. Methods We used online searching tools including MEDLINE (PubMed), Embase, Cochrane Library, and Google Scholar by combining keywords such as “titanium implant toxicity,” “titanium implant corrosion,” “titanium implant allergy,” and “yellow nail syndrome.” Recently updated data has been collected and compiled into one of four categories: “the toxicity of titanium,” “the toxicity of titanium alloys,” “the toxicity of titanium implants,” and “diseases related to titanium.” Results Recent studies with regard to titanium toxicity have been increasing and have now expanded to the medical field in addition to the fields of environmental research and basic science. Problems that may arise in titanium-based dental implants include the generation of titanium and titanium alloy particles and ions deposited into surrounding tissues due to the corrosion and wear of implants, resulting in bone loss due to inflammatory reactions, which may lead to osseointegration failure of the dental implant. These titanium ions and particles are systemically deposited and can lead to toxic reactions in other tissues such as yellow nail syndrome. Additionally, implant failure and allergic reactions can occur due to hypersensitivity reactions. Zirconia implants can be considered as an alternative; however, limitations still exist due to a lack of long-term clinical data. Conclusions Clinicians should pay attention to the use of titanium dental implants and need to be aware of the problems that may arise from the use of titanium implants and should be able to diagnose them, in spite of very rare occurrence. Within the limitation of this study, it was suggested that we should be aware the rare problems of titanium toxicity.
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Aluminum (Al) is the third most abundant element in the earth's crust and is omnipresent in our environment, including our food. However, with normal renal function, oral and enteral ingestion of substances contaminated with Al, such as antacids and infant formulae, do not cause problems. The intestine, skin, and respiratory tract are barriers to Al entry into the blood. However, contamination of fluids given parenterally, such as parenteral nutrition solutions, or hemodialysis, peritoneal dialysis or even oral Al-containing substances to patients with impaired renal function could result in accumulation in bone, parathyroids, liver, spleen, and kidney. The toxic effects of Al to the skeleton include fractures accompanying a painful osteomalacia, hypoparathyroidism, microcytic anemia, cholestatic hepatotoxicity, and suppression of the renal enzyme 25-hydroxyvitamin D-1 alpha hydroxylase. The sources of Al include contamination of calcium and phosphate salts, albumin and heparin. Contamination occurs either from inability to remove the naturally accumulating Al or from leeching from glass columns used in compound purification processes. Awareness of this long-standing problem should allow physicians to choose pharmaceutical products with lower quantities of Al listed on the label as long as this practice is mandated by specific national drug regulatory agencies. Keywords: Aluminum toxicity, Bone, Parathyroid glands, Liver, Osteomalacia
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Commercially pure titanium (Ti G2 and Ti G4) and the Ti-6Al-4V (Ti G5) alloy have limitations for biomedical applications, due to either low mechanical strength (Ti G2, Ti G4) or the possible release of toxic ions (Ti G5). Since Ti alloys have a low hardening coefficient, it is very difficult to improve their mechanical properties by work hardening. The purpose of this work was to compare the mechanical and clinical properties of Ti G4 nanostructured after severe plastic deformation by ECAP (Ti G4 Hard) with those of Ti G2, Ti G4 and Ti G5. Bars, disks and dental implants made with Ti G2, Ti G4, Ti G5 and Ti G4 Hard were tested. Mechanical tests (tension, compression, hardness, elastic modulus, fatigue and torque) and roughness measurements were performed. The results of the mechanical tests showed that Ti G4 Hard has a higher mechanical strength and a lower elastic modulus than Ti G2, Ti G4 and Ti G5. Scanning electron microscopy and roughness measurements results showed that acid etched Ti G4 Hard nanostructured has better surface morphological features than Ti G2, Ti G4 and Ti G5. The clinical performances of Ti G4 and Ti G4 Hard were similar. The high mechanical strength of Ti G4 Hard means that it can be used to replace Ti G5 in several clinical applications, with the advantage of not releasing toxic ions. The Ti G4 Hard dental implants have adequate mechanical properties and can be inserted in areas with low bone volume. © 2018 Brazilian Metallurgical, Materials and Mining Association.
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The purpose of this study was to evaluate the effect of total implant-bone surface contact area of dental implants applied on partial or total edentulous patients on the increase in the level of blood titanium level. Changes of the blood titanium levels were evaluated after placement of the dental implants in 30 patients including 15 females and 15 males. Patients were divided into 3 groups as dental implants were applied on only maxilla, only mandible, or both of them. Taking into the consideration anatomic formation and prosthetic indication, dental implant-bone total contact area was calculated and saved for each patient after dental implants placement. Blood samples of the patients taken preoperatively and postoperatively at 12 weeks were analyzed by ICP-MS device. Blood titanium levels of preoperative and postoperative blood samples were analyzed for each patient and results were evaluated statistically. In the evaluation after analyzing blood titanium level changes, while a statistically significant decrease was observed in Group 1 patients, a statistically significant increase was observed in Group 2 and Group 3 patients to blood titanium level. A statistically significant difference was observed between Group 1 and Group 2 and between Group 1 and Group 3 patients of blood titanium levels. The change of the blood titanium level was not related to total implant-bone surface area, number of the implants, and gender. In our study, no correlation was found between change of blood titanium level and total contact area with bone of dental implants. We believe that more accurate results can be obtained with biopsy of tissues and organs on animal studies.
Implants into the human body, such as hip joints, heart valves and dental crowns, have been increasingly used over the last 40 years or so, and many patients have benefited from their use. But how much is known about the metals, ceramics and polymers that are used in these repairs? This book provides a state-of-the-art account of the chemistry of the synthetic materials used in medicine and dentistry. It looks at the properties and interactions of these materials within the body at a molecular level, and includes discussion of bioengineering and cell biology. In addition, there is an account of the surgical procedures used, as well as extensive coverage of the possible biological reactions to the presence of foreign materials in the body. A brief look at the emerging field of tissue engineering completes the text. Fully referenced, with detailed reviews of the current literature, The Chemistry of Medical and Dental Materials will be an essential starting-point for all those in academia and industry who are involved in the development of new and improved repair materials.
Bioactive titanium metal, which forms a bonelike apatite layer on its surface in the body and bonds to the bone through the apatite layer, can be prepared by NaOH and heat treatments to form an amorphous sodium titanate layer on the metal. In the present study, the mechanism of apatite formation on the bioactive titanium metal has been investigated in vitro. The metal surface was examined using transmission electron microscopy and energy dispersive X‐ray spectrometry as a function of the soaking time in a simulated body fluid (SBF) and complemented with atomic emission spectroscopy analysis of the fluid. It was found that, immediately after immersion in the SBF, the metal exchanged Na⁺ ions from the surface sodium titanate with H3O⁺ ions in the fluid to form Ti‐OH groups on its surface. The Ti‐OH groups, immediately after they were formed, incorporated the calcium ions in the fluid to form an amorphous calcium titanate. After a long soaking time, the amorphous calcium titanate incorporated the phosphate ions in the fluid to form an amorphous calcium phosphate with a low Ca/P atomic ratio of 1.40. The amorphous calcium phosphate thereafter converted into bonelike crystalline apatite with a Ca/P ratio of 1.65, which is equal to the value of bone mineral. The initial formation of the amorphous calcium titanate is proposed to be a consequence of the electrostatic interaction of negatively charged units of titania, which are dissociated from the Ti‐OH groups, with the positively charged calcium ions in the fluid. The amorphous calcium titanate is speculated to gain a positive charge and to interact with the negatively charged phosphate ions in the fluid to form the amorphous calcium phosphate, which eventually stabilizes into bonelike crystalline apatite. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 441–448, 2001
Compared with stainless steel and Co–Cr‐based alloys, Ti and its alloys are widely used as biomedical implants due to many fascinating properties, such as superior mechanical properties, strong corrosion resistance, and excellent biocompatibility. After briefly introducing several most commonly used biomedical materials, this article reviews the recent development in Ti alloys and their biomedical applications, especially the low‐modulus β‐type Ti alloys and their design methods. This review also systemically investigates the recently attractive progress in preparation of biomedical Ti alloys, including additive manufacturing, porous powder metallurgy, and severe plastic deformation, applied in the manufacturing and the influenced microstructures and properties. Nevertheless, there are still some problems with the long‐term performance of Ti alloys, and therefore several surface modification methods are reviewed to further improve their biological activity, wear resistance, and corrosion resistance. Finally, the biocompatibility of Ti and its alloys is concluded. Summarizing the findings from literature, future prediction is also conducted.
Introduction: Titanium based (Ti-based) materials have been used as dental implants due to their high biocompatibility, good mechanical strength and ideal osseointegration properties. Osseointegration of an implant is dependent on surface characteristics such as surface chemistry and topography. Nanotechnology has presented new and interesting applications in dentistry in recent years. The presence of nanoparticles on the implant surface can affect both the topography and surface chemistry, leading to different and outstanding specifications for implant. Method: A literature review was performed in electronic databases by means of MeSH keywords to collect relevant published literature in English about the effect of nanohydroxyapatite on osseointegration of titanium implants. No limitations on publication date were imposed. Data regarding titanium implants; nanotechnology; nanohydroxyapatite; osseointegration and cell attachment were collected and reviewed. Results and conclusion: According to reviewed literature, nanohydroxyapatites have a nanostructured surface with higher surface area and then higher reactivity, letting them to bind to bone creating a biomimetic coating on implants. However, more studies are needed on the cell-substrate interface to develop an effective implant due to the interaction of the cells and the biomaterial surface after the implantation.