Next Article in Journal
Numerical Simulation and Analytical Prediction of Residual Strength for Elbow Pipes with Erosion Defects
Previous Article in Journal
Low-Frequency Noise Characteristics in HfO2-Based Metal-Ferroelectric-Metal Capacitors
Previous Article in Special Issue
Dentin Exposure after Tooth Preparation for Laminate Veneers: A Microscopical Analysis to Evaluate the Influence of Operators’ Expertise
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Materials
Volume 15
Issue 21
10.3390/ma15217476
materials-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Minimization of Adverse Effects Associated with Dental Alloys

by
Marianna Arakelyan
1,
Gianrico Spagnuolo
2,*,
Flavia Iaculli
2,
Natalya Dikopova
1,
Artem Antoshin
3,4,
Peter Timashev
3,4,5 and
Anna Turkina
1
1
Therapeutic Dentistry Department, Institute for Dentistry, Sechenov University, 119991 Moscow, Russia
2
Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples “Federico II”, 80138 Napoli, Italy
3
Institute for Regenerative Medicine, Sechenov University, 119991 Moscow, Russia
4
World-Class Research Center “Digital Biodesign and Personalized Healthcare”, Sechenov University, 119991 Moscow, Russia
5
Chemistry Department, Lomonosov Moscow State University, 119234 Moscow, Russia
*
Author to whom correspondence should be addressed.
Materials 2022, 15(21), 7476; https://doi.org/10.3390/ma15217476 (registering DOI)
Submission received: 21 September 2022 / Revised: 17 October 2022 / Accepted: 21 October 2022 / Published: 25 October 2022
(This article belongs to the Special Issue Current and Future Trends in Dental Materials, Volume II)
Browse Figures
Versions Notes

Abstract

:
Metal alloys are one of the most popular materials used in current dental practice. In the oral cavity, metal structures are exposed to various mechanical and chemical factors. Consequently, metal ions are released into the oral fluid, which may negatively affect the surrounding tissues and even internal organs. Adverse effects associated with metallic oral appliances may have various local and systemic manifestations, such as mouth burning, potentially malignant oral lesions, and local or systemic hypersensitivity. However, clear diagnostic criteria and treatment guidelines for adverse effects associated with dental alloys have not been developed yet. The present comprehensive literature review aims (1) to summarize the current information related to possible side effects of metallic oral appliances; (2) to analyze the risk factors aggravating the negative effects of dental alloys; and (3) to develop recommendations for diagnosis, management, and prevention of pathological conditions associated with metallic oral appliances.

1. Introduction

Metal alloys are one of the most popular materials used in current dental practice. Metals are used in the fabrication of artificial crowns and bridges, prefabricated posts and cast post-and-core inlays, clasp removable dentures and dental implants, as well as fixed orthodontic equipment. More than half of Europeans have at least one metal structure in their oral cavity, such as an artificial crown, inlay, or dental bridge [1]. In the last 20 years, there has been a steady upward trend in the number of people having dental implants. For example, in the USA, the proportion of people with at least one dental implant increased from 0.7% to 5.7% between 2000 and 2016. According to the experts, by 2026, the proportion of people with dental implants may reach 23% [2]. Moreover, the use of fixed orthodontic appliances is also predicted to rise, including in the adult category [3]. The most commonly used metal alloys in dentistry include cobalt-chromium, nickel-titanium, nickel-chromium, and titanium alloys.
In some cases, the interaction of dental alloys with the environment of the oral cavity may cause undesirable phenomena that not only worsen the quality of life of the patient but also may negatively affect oral tissues [4,5] or even the whole organism [6].
The present comprehensive literature review aims (1) to summarize the current information related to possible side effects of metallic oral appliances; (2) to analyze the risk factors aggravating the negative effects of dental alloys; and (3) to develop recommendations for diagnosis, management, and prevention of pathological conditions associated with metallic oral appliances.

2. The Main Effects of Dental Alloys on the Human Organism

In the oral cavity, the metallic structures are exposed to various extra-oral and intra-oral factors, which may cause their corrosion (Figure 1). Chemical corrosion is associated with saliva, exposure to acids from sour food and drinks, and exposure to acids produced by oral biofilm [7]. Moreover, the metallic appliances are affected by mastication load and oral hygiene products, which lead to mechanical-chemical corrosion [8]. The friction and wear of two contacting metallic appliances in a corrosive media is termed tribocorrosion [9]. Tribocorrosion may cause degradation of dental implants, which are usually composed of several metallic structures [10]. Galvanic corrosion of dental alloys occurs when two metallic appliances with different electrochemical potentials interact in the electrolytic medium (saliva) [11]. As a result of the corrosion, metal ions are released into the saliva and adjacent oral mucosa [12].
The main effects of metal ions on the human organism are shown in Figure 2. The first effect is local cytotoxity. It has been shown that ions released from dental alloys may negatively affect periodontal fibroblasts [13,14] and epithelial cells [15]. The main mechanisms of metal cytotoxity are apoptosis [16] and oxidative stress [17,18], which may increase the risk of potentially malignant oral lesions [19]. Moreover, metal ions, including Ti4+, may stimulate the release of inflammatory mediators and tumor necrosis factor, causing chronic inflammation of the oral mucosa and peri-implant tissues [20,21,22]. Indeed, several in vivo and in vitro studies demonstrated that ions released from dental alloys could damage the DNA of oral mucosa cells [23,24,25,26]. However, other researchers revealed no genotoxic effect of Ti-based dental alloys and orthodontic alloys [27,28,29].
The second effect is allergic reactions. Metal ions may interact with human proteins as haptens and initiate hypersensitivity reactions [6,30]. The pathogenesis of the allergic reaction may be different, but the most common is a type IV reaction manifesting as chronic inflammation with lymphoid infiltration [31]. The corresponding immune response may develop in the form of local conditions such as lichenoid reaction [32] or may involve other tissues and organs [33,34].
Moreover, metal ions are swallowed together with saliva and, potentially, may accumulate in different tissues and organs [35]. However, the systemic toxic effect of dental alloys is doubtful as the daily intake of metal ions from intraoral appliances is much below the toxic limit value [36,37,38].
Another significant problem is galvanic current that occurs when dissimilar metals are present in the oral cavity with saliva serving as an electrolyte [39]. Back in 1984, S. Ayers mentioned that the direct current below the level of 10 µA is not critical [40]. According to von Fraunhofer et al., a galvanic current of 20 µA is associated with a pain reaction [41]. The current from 75 µA to 100 µA may cause chronic irritation of oral mucosa [40]. Chronic electrical trauma of the oral mucosa is considered a risk factor for different oral lesions, including potentially malignant lesions such as verrucous leukoplakia and oral lichen planus [11]. For example, Wartenberg et al. applied direct current to the oral carcinoma cell culture and observed apoptosis [42], while Korrah et al. on leukoplakia cells showed that the direct current may cause effects similar to those in the case of malignization [43].
However, in the oral cavity, it is difficult to clarify the leading pathogenesis mechanism since a synergistic effect of two or even three factors may be observed.

3. Clinical Manifestations of Adverse Effects Associated with Dental Alloys

Adverse events associated with dental alloys can be conditionally divided into local and systemic ones. In addition, special attention should be paid to the potential relationship between the presence of metal structures in the oral cavity and the development of systemic diseases.

3.1. Local Manifestations

The most common local reactions are as follows:
  • mouth burning without any visible lesions of the oral mucosa is commonly associated with galvanic current between different dental alloys. According to different authors, in patients with metal structures in the mouth, a burning sensation was observed with a frequency of 17% to 33% [39,44,45,46]. However, it should be kept in mind that burning mouth syndrome may develop in patients without metallic appliances and may be associated with a number of other systemic and local factors, such as vitamin deficiency, hormonal changes associated with menopause, local infections of the oral cavity, xerostomia, denture-related lesions, allergies, medications, and systemic diseases, including diabetes mellitus [47].
  • oral lichen planus and lichenoid reaction (Figure 3a) manifest as multiple white papules, merging into the characteristic Wickham rete [48]. According to different authors, these phenomena are observed with a frequency of 12% to 78% among patients with metal structures in the mouth [44,49,50]. The condition may develop due to chronic irritation by galvanic current or as a delayed-type hypersensitivity reaction. Lichenoid reactions of the oral cavity are histologically or clinically indistinguishable from lichen planus, even though the latter may present within skin lesions and is not necessarily localized in direct contact with a metal structure. Both lichenoid reactions and lichen planus are precancerous [51].
  • pigmentation of oral mucosa (Figure 3b) appears as a dark spot on the mucosa near to the metal structure, and it most often occurs upon contact with amalgam and silver-containing alloys. Moreover, metal particles can deposit on the oral mucosa during the placement or removal of amalgam fillings and appear as dark pigmented lesions [52]. In the presence of a galvanic couple, the pigmentation processes can be enhanced [53]. However, it must be taken into account that any dark pigmented lesion can be not only a benign discoloration but also potentially represent melanoma [54,55,56,57].
  • leukoplakia (Figure 3c) is characterized by the emergence of increased keratinization areas on the mucous membrane. The prevalence of leukoplakia ranges from 0.5 to 3.4% and occurs most often in people older than 50 years [58]. It should be noted that the frequency of malignant transformation of leukoplakia ranges from 0.1 to 17% [59]. According to the observations of Gönen Z.B. et al., hyperkeratotic lesions may occur due to a hypersensitivity reaction to amalgam [58].
  • erosive and ulcerative lesions (Figure 3d) are mostly the form of allergic reactions to metals and manifest as recurrent aphthous stomatitis [60].

3.2. Systemic Adverse Effects of Dental Alloys

Commonly, systemic adverse effects of dental alloys are associated with hypersensitivity reactions, which may include typical clinical manifestations such as dermatitis, itching, eczema, and Quincke’s edema [33,61]. Moreover, chronic fatigue syndrome, headaches, and polyarthritis were observed [62,63]. An interesting case report of allergic gastritis associated with dental alloys was published by Pföhler et al. in 2016 [64]. In 2020, Zigante et al. examined 228 patients with fixed orthodontic appliances. Hypersensitivity to titanium and nickel was diagnosed in 16% of study participants. The symptoms associated with hypersensitivity were as follows: hypogeusia, hyposmia, tongue or face edema, and watering [65].

3.3. Associations between Dental Alloys and Systemic Diseases

Potential risks associated with dental amalgam are widely discussed in the literature. Mercury may cause oxidative stress, damage mitochondria and lipid membranes, change DNA structure and stimulate autoimmunity [66], which potentially may increase the risk of neurodegenerative diseases. Within the last 20 years, clinical studies evaluated possible associations of dental amalgam with neurological and autoimmune diseases and showed controversial results [67,68,69,70,71]. According to the systematic review published by Gallusi et al. in 2021, amalgam restorations are not associated with an increased risk of any systemic disease [72]. Nevertheless, the issue of the potential toxicity of mercury released from dental amalgams is a matter of debate in the scientific literature [73].
The new diagnostic methods for metal hypersensitivity detection allowed the researchers to explore the role of dental alloys in the pathogenesis of autoimmune diseases. Several studies have shown an association between sensitivity to one or more metals and the severity of different autoimmune diseases [74,75,76,77]. In contrast, clinical studies demonstrated that metallic oral appliances did not increase the risk of autoimmune diseases [78,79,80].
However, it should be stressed that metallic intra-oral appliances are not always associated with any side effects, even in the case of galvanic coupling of dental alloys [81] or even if the patients are sensitive to metals [82]. It may be hypothesized that clinical reaction to dental alloys strongly depends on the patient’s individual characteristics such as composition and possible galvanic coupling of dental alloys, saliva properties, oral hygiene, dietary behaviors, systemic diseases, etc. Risk factors aggravating dental alloy side effects are further discussed below.

4. Factors Affecting the Risk of Dental Alloys Side Effects

Factors which may aggravate the negative effects of metallic oral appliances are listed in Table 1.

4.1. Corrosion Resistance and Biocompatability of Common Dental Alloys

Among all dental alloys, dental amalgam and nickel-chromium alloys are supposed to have the least corrosion resistance both in the artificial saliva and in the acidic environment [83,84]. The common amount of absorbed mercury from amalgam restoration is reported to be less than 5 µg per day [73], but the levels of mercury accumulation and excretion are determined genetically and may significantly differ between individuals [85]. The release of nickel ions may reach 5.22 µg/cm2/day from nickel-chromium alloy [38] and 0.93 µg/day from orthodontic archwires [86]. Cobalt-chromium alloys are more resistant to corrosion, as it was shown by Kaasapidou et al., the Co ion release per 7 days did not exceed 2.6 µg/cm2 [87]. Pure titanium and titanium alloys are commonly used for dental implants. In general, titanium is resistant to corrosion due to the formation of titanium dioxide film on its surface [88], but dental implants may release titanium in the form of nanoparticles both within the implantation procedure and after prolonged interaction with the oral environment [21,22]. To reduce corrosion, titanium may be alloyed with Al, V, Zr, Ta, Mo, or Cr [89]. Titanium alloys are more corrosion resistant compared to pure titanium [90], and the release of Ti from TiAlV alloy was shown to be 16 ng/cm2/day [91]. Moreover, it should be noted that Ti alloy may become the source of V and Al ions, which are potentially toxic [91,92].
The galvanic current depends on the potential differences between dental alloys. According to the multiple in vitro studies, significant galvanic current may occur in the following galvanic couples: dental amalgam and cobalt-chromium alloy [93,94]; titanium alloy and dental amalgam [95]; nitinol archwire and titanium brackets [96]; nitinol archwire and iron brackets [96,97]; titanium dental implant and cobalt-chromium or nickel-chromium alloys [98,99,100,101]. Moreover, the surface area of metallic appliances should be taken into account. For instance, Nayak et al. in 2015 showed that the current increased together with increasing of cathode surface area and decreasing of anode surface area [97].
Regarding the tribocorrosion, the titanium–titanium combination showed more wear than titanium-zirkonia and titanium-Roxolid [102].
It should be noted that the data related to corrosion of dental alloys are mainly obtained in experimental studies, which cannot always be clinically proven. The standard methods for corrosion assessment are recommended by ISO 10271:2020 and include static immersion tests with lactic acid, sulfide tarnish static/cyclic immersion tests, and electrochemical tests [103]. However, many studies use artificial saliva with additional components such as fluoride, lisozyme or urea [83]. In addition, experimental models reproducing saliva flow [38] or tribocorrosion [104] were introduced.
As for the cytotoxicity of common ions released from dental alloys, Ni, Zn, and Cu ions were defined as the most toxic elements, while Fe, Cr, Mo, Al, and Pd ions showed less cytotoxic effects [20,105,106]. Ti is supposed to be much more biocompatible than other metals, however, Ti ions released from dental implants may cause periimplantitis or type IV allergic reactions [107]. Evaluation of dental alloy biocompatibility is standardized by ISO 7405:2018 which refers to in-vitro cytotoxicity assessment with cell culture (direct contact tests or extract tests) [108]. To close the experimental conditions to a real clinical situation, new tissue models were developed. Commercially available three-dimensional models of keratinized and non-keratinized oral epithelium are suitable for evaluation of dental materials’ effects on the oral mucosa [109]. Oral mucosa-on-a-chip is a complex model that allows assessing the effects of dental materials on different layers of the oral mucosa, including keratinocytes, fibroblasts, and collagen [110]. Moreover, recently, the new multi-organ-on-chip model was developed for the evaluation of the systemic toxicity of dental alloys [111]. The future use of standardized tissue models will ensure accurate and reproducible results related to local and systemic effects of dental alloys.

4.2. Composition and pH of the Saliva

Saliva plays a crucial role in the surface degradation of metallic oral appliances.
Saliva is an electrolytic medium in which normal electroconductivity varies from 3.5 mS/cm to 4.73 mS/cm [112,113,114]. However, pH, ionic composition, and, accordingly, electroconductivity of the whole saliva may significantly vary both between individuals and within individuals depending on the age [115], time of the day [116], and even on the menstrual cycle phase [117]. The decrease in salivary pH is the significant factor aggravating chemical corrosion and galvanic corrosion [100,118]. The decrease in salivary pH is commonly observed in patients with periodontal disease [119] and in patients with multiple caries [120]. Moreover, many systemic diseases and conditions may change the electrochemical characteristics of saliva [112,121,122,123,124,125,126].
It was also shown that an increased level of carbamide in saliva significantly enhances corrosion of dental alloys [127]. The effects of proteins are poorly investigated. On the one hand, proteins, especially mucine, form a protective film on the metallic surfaces and reduce tribocorrosion [128]. On the other hand, some proteins may stimulate corrosion, wherein different proteins even with similar amino acids may show different effects on dental alloys [129].

4.3. Oral Microbiota

Dental biofilm plays a significant role in the biodegradation of dental alloys. Acidogenic bacteria such as Streptococcus mutans, Lactobacillus reuteri, Streptococcus sanguis, Streptococcus mitis, Streptococcus sobrinus, Streptococcus salivarius, sulfate-reducing bacteria, sulfate-oxidizing bacteria, Veilonella, Actinomyces, and Candida albicans may aggravate corrosion of dental alloys [7,130,131]. Lipopolysaccharide of microbial origin dramatically increases tribocorrosion of dental implants [132]. On the other hand, normal oral microbiota such as Streptococcus salivarius work as lubricant on the metal surface and reduce tribocorrosion of metallic appliances in the oral cavity [133].

4.4. Oral Care Products

Toothpastes and mouthrinses play a central role in the chemo-mechanical wear of all dental materials, including dental alloys. According to experimental tests, abrasive toothpastes cause degradation of the dental alloy surface quality, which leads to increased ion release, although the surface roughness remains within the normal range [134,135,136,137]. It should be noted that increased fluoride concentration in the oral environment dramatically increases galvanic corrosion of dental alloys [134,138,139,140], therefore, patients with metallic appliances are not recommended to use oral care products with fluorides. It was shown that Listerine® mouthwash may stimulate nickel ions release and change the surface properties of nickel-titanium orthodontic archwires [141,142]. Chlorhexidine may increase corrosion of orthodontic implants [143], although a similar effect for brackets was not observed [139]. Ethanol-containing mouthwashes are supposed to be the most aggressive to dental alloys due to increased galvanic corrosion [139,144].
It is noteworthy that saliva replacement products, permanently used by xerostomic patients, may also influence galvanic and corrosion processes in the oral cavity. Spirk et al. figured out that the electroconductivity of several saliva replacements was up to two times higher than natural saliva [113].

4.5. Dietary Behaviors

The acidity of common foods and beverages may potentially influence the corrosion of dental alloys. Shahabi et al. showed that frequent intake of acidic products may significantly increase the corrosion of orthodontic brackets [145]. Recently, the effect of brewed coffee may increase ion release from nickel titanium alloy due to the decreased pH of saliva mixed with coffee [146]. Conversely, Parenti et al. detected in vitro no effect of acidic beverages on the surface structure of nickel-titanium orthodontic archwires [147].

4.6. Bad Habits

Tobacco smoke damages oral mucosa cells [148], slows regeneration [149], and increases the risk of potentially malignant oral lesions [150,151]. Regular alcohol consumption also negatively affects oral mucosa cells [152] and may stimulate malignant transformation of oral lesions [153]. Therefore, it can be assumed, that smoking and alcohol intake would aggravate any side effects associated with dental alloys. Moreover, considering the effect of ethanol-based oral rinses on dental alloys [139,144], we may suppose that alcohol may increase corrosion and galvanic processes in the oral cavity.

4.7. Systemic Diseases and Conditions

Post-menopausal women are often mentioned as a risk group for mouth burning. According to previously published data, for post-menopausal women, the following changes in the oral cavity are commonly observed: decreased salivation, decreased salivary pH, and increased Ca2+ concentration in the whole saliva [154,155]. Moreover, the oral mucous membrane becomes more sensitive to different irritants, and taste disorders and mouth burning are also common [156]. As a result, post-menopausal women may potentially be more sensitive to galvanic current and should be included in the risk group for dental alloy side effects.
Gastroesophageal reflux disease should also be mentioned as a significant factor of dental alloy biodegradation, both due to the regular drop of intra-oral pH and the change of ionic composition of the whole saliva [121,122].
Diabetes mellitus is commonly associated with increased sensitivity of oral mucosa due to peripheral and autonomic neuropathy [157], which may increase mouth burning in the case of galvanic coupling of dental alloys in the oral cavity. Another factor increasing galvanic corrosion of dental alloys in patients with diabetes mellitus is the decreased salivary pH [126,158].
Similar symptoms are observed in patients with thyroid hypofunction: decreased pH of the whole saliva [123], altered taste [159], and mouth burning [160].
Electroconductivity of whole saliva increases in patients with dehydration associated with renal diseases or increased physical activity [112].
As mentioned above, patients with autoimmune diseases often have hypersensitivity to metals. That is why metallic oral appliances may worsen the patient’s condition [77,161]. In addition, increased electroconductivity of the saliva and poor healing potential of the oral mucosa were shown in patients after radiotherapy [113].

5. Approaches to Reduce the Risk of Adverse Events Associated with Dental Alloys

5.1. Industrial Methods to Reduce Corrosion of Dental Alloys

Corrosion resistance of dental alloys is affected not only by composition but also by manufacturing method [87] and surface polishing [162]. Several methods have been suggested to improve the corrosion resistance of oral metallic appliances.
Chemical passivation aims to form a protective oxide layer on the appliance surface. It was shown that corrosion of passivated cobalt-chromium alloy was significantly lower compared to non-passivated samples [163]. Citric acid passivation of dental implants may also be useful to minimize corrosion [164]. Another method to obtain a thick and stable oxide layer on the metal surface is plasma electrolytic oxidation [165].
Surface coating of dental implants is used to enhance osseointegration and reduce corrosion [166]. The protective layer on the surface may be formed in different ways, including sol-gel surface coating, physical or chemical vapor deposition, and plasma spraying [89].
Plasma immersion ion implantation is used for surface modification of dental implants with different ions to enhance biocompatibility [167,168].
Layer-by-layer electrostatic self-assembly is also a promising method of titanium surface modification based on interactions of different electrolytes. With this method, new properties of the implant surface may be achieved, such as bone healing stimulation, antibacterial effect, corrosion resistance, etc. [169].
Short-term clinical trials showed faster osseointegration of dental implants after different surface treatments [170,171]. However, it should be noted that there is a lack of clinical evidence regarding the long-term effects of dental implant surface modification and the potential impact on bio-tribocorrosion has not been studied sufficiently [172].

5.2. Clinical Recommendations for Treatment Planning

The treatment plan should be developed considering the information about the patient’s general medical history. Given that patients having gastrointestinal problems, endocrine diseases, or autoimmunity may have an increased risk of dental alloys’ side effects, physician consultation is recommended. If possible, non-metal prosthetic appliances should be used. If not, one should avoid using dental alloys with low corrosion resistance and galvanic coupling of dental alloys. Furthermore, a history of any allergic reactions to metals or metal intolerance such as contact allergy to jewelry is an indication for a complete allergy examination, including patch-testing and blood tests [173]. Given that the patch-test may cause false-positive reactions, an optimized lymphocyte transformation test (LTT) should be used to confirm the diagnosis of metal hypersensitivity [63].
In the case of pre-existing oral lesions such as leukoplakia, oral lichen planus, or recurrent aphthous stomatitis, additional allergy tests are required before the treatment. If possible, non-metal appliances or noble dental alloys should be preferred.
If any metallic appliances are already present in the oral cavity, it would be useful to know their exact composition to avoid galvanic coupling with new dental alloys. Anyway, the method of choice is complete prosthetic rehabilitation using a dental alloy with high corrosion resistance.

5.3. Recommendations for Patients with Metallic Prosthetic or Orthodontic Appliances

To minimize the risk of adverse events, it would be useful to avoid factors increasing corrosion of dental alloys, for example: smoking and hard alcohol consumption, use of ethanol-based mouth rinses and fluoride-containing oral hygiene products, use of abrasive toothpastes, and regular intake of acidic foods and beverages.

5.4. Recommendations for Patients with Oral and/or Systemic Symptoms, Potentially Associated with Dental Alloys

As mentioned above, the most common clinical manifestations of adverse effects associated with dental alloys include allergic reactions, mouth burning, and white oral lesions. Regarding hypersensitivity, it may be diagnosed by the use of skin or blood tests. Nevertheless, the diagnosis of oral galvanism remains a complicated issue since, to date, there is no standardized method for the determination of intra-oral electric currents. Several clinical studies reported intra-oral galvanic current assessment with the zero-resistance ammeter [41,174] or with a specialized dental voltmeter/ammeter [175]. It should also be taken into account that the current strongly depends on the electrical resistance of the intra-oral medium, which is very changeable. Another method for galvanism diagnosis is the measurement of electrochemical potentials of metallic appliances and the determination of potential differences between coupling dental alloys [11,53,81]. However, these methods are not widely used in routine dental practice, and dentists commonly opt for the replacement of metallic appliances according to patients’ complaints and clinical symptoms.
Replacement of dental alloys may be recommended in the following cases: flare-up of autoimmune diseases; severe mouth burning that appears after placement of metallic appliances; positive path-test or blood test to components of dental alloys; and the appearance of potentially malignant oral lesions [58]. As the clinical picture of dental alloys’ side effects is not specific, other diseases with similar symptoms should be excluded before replacement of metallic appliance, and all the other possible causes should be eliminated (Figure 4).

6. Conclusions

The issue of adverse events associated with dental alloys remains due to the extensive use of different metallic appliances in dentistry. The side effects of dental alloys may have multiple local and systemic manifestations, which may affect the quality of life and complicate the diagnosis. Since the replacement of dental implants and prosthetic appliances is a time-consuming and expensive procedure, dentists should focus on prevention rather than on diagnosis and treatment of adverse events. Therefore, understanding the basic pathogenesis mechanisms and risk factors of dental alloys’ side effects is necessary to provide an optimal treatment plan and recommendations for patients with metallic oral appliances.

Funding

The study was supported by Russian Science Foundation № 22-25-00796, https://rscf.ru/project/22-25-00796/ accessed on 10 January 2022.

Institutional Review Board Statement

The intraoral photographs presented in the review were obtained within the clinical study: Evaluation of the electrochemical potentials of metal structures in the oral cavity. All subjects gave their informed consent for participation in the study. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Sechenov University (Protocol N10-19).

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

Authors declare no conflict of interest.

References

  1. Zitzmann, N.U.; Hagmann, E.; Weiger, R. What Is the Prevalence of Various Types of Prosthetic Dental Restorations in Europe? Clin. Oral Implants Res. 2007, 18 (Suppl. 3), 20–33. [Google Scholar] [CrossRef] [PubMed]
  2. Elani, H.W.; Starr, J.R.; Da Silva, J.D.; Gallucci, G.O. Trends in Dental Implant Use in the U.S. 1999–2016, and Projections to 2026. J. Dent. Res. 2018, 97, 1424–1430. [Google Scholar] [CrossRef] [PubMed]
  3. Borghei, S.; Broadbent, J.; Stevens, R.; Chaudhry, K.; Subramani, K. Orthodontists’ Preference on Type of Rigid Fixed Functional Appliance for Skeletal Class II Correction: A Survey Study. J. Clin. Exp. Dent. 2020, 12, e958–e963. [Google Scholar] [CrossRef]
  4. Marek, M. Interactions between Dental Amalgams and the Oral Environment. Adv. Dent. Res. 1992, 6, 100–109. [Google Scholar] [CrossRef] [PubMed]
  5. Martin, M.D.; Broughton, S.; Drangsholt, M. Oral Lichen Planus and Dental Materials: A Case-Control Study. Contact Dermat. 2003, 48, 331–336. [Google Scholar] [CrossRef] [PubMed]
  6. Martin, S.F. T Lymphocyte-Mediated Immune Responses to Chemical Haptens and Metal Ions: Implications for Allergic and Autoimmune Disease. Int. Arch. Allergy Immunol. 2004, 134, 186–198. [Google Scholar] [CrossRef] [PubMed]
  7. Gopalakrishnan, U.; Felicita, A.S.; Mahendra, L.; Kanji, M.A.; Varadarajan, S.; Raj, A.T.; Feroz, S.M.A.; Mehta, D.; Baeshen, H.A.; Patil, S. Assessing the Potential Association Between Microbes and Corrosion of Intra-Oral Metallic Alloy-Based Dental Appliances Through a Systematic Review of the Literature. Front. Bioeng. Biotechnol. 2021, 9, 631103. [Google Scholar] [CrossRef]
  8. Kaličanin, B.; Ajduković, Z. Influence of Saliva Medium on Freeing Heavy Metal Ion from Fixed Dentures. Sci. Total Environ. 2008, 397, 41–45. [Google Scholar] [CrossRef]
  9. Mathew, M.T.; Kerwell, S.; Lundberg, H.J.; Sukotjo, C.; Mercuri, L.G. Tribocorrosion and Oral and Maxillofacial Surgical Devices. Br. J. Oral Maxillofac. Surg. 2014, 52, 396–400. [Google Scholar] [CrossRef]
  10. Revathi, A.; Borrás, A.D.; Muñoz, A.I.; Richard, C.; Manivasagam, G. Degradation Mechanisms and Future Challenges of Titanium and Its Alloys for Dental Implant Applications in Oral Environment. Mater. Sci. Eng. C Mater. Biol. Appl. 2017, 76, 1354–1368. [Google Scholar] [CrossRef]
  11. Dikopova, N.Z.; Volkov, A.G.; Arakelyan, M.G.; Makarenko, N.V.; Soxova, I.A.; Doroshina, V.J.; Arzukanyan, A.V.; Margaryan, E.G. The Study of the Electrochemical Potentials of Metal Structures in the Oral Cavity in Diseases of the Oral Mucosa. New Armen. Med. J. 2020, 14, 54–58. [Google Scholar]
  12. Mikulewicz, M.; Chojnacka, K.; Woźniak, B.; Downarowicz, P. Release of Metal Ions from Orthodontic Appliances: An in Vitro Study. Biol. Trace Elem. Res. 2012, 146, 272–280. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  13. Nimeri, G.; Curry, J.; Berzins, D.; Liu, D.; Ahuja, B.; Lobner, D. Cytotoxic Evaluation of Two Orthodontic Silver Solder Materials on Human Periodontal Ligament Fibroblast Cells and the Effects of Antioxidant and Antiapoptotic Reagents. Angle Orthod. 2021, 91, 349–355. [Google Scholar] [CrossRef]
  14. Ortiz, A.J.; Fernández, E.; Vicente, A.; Calvo, J.L.; Ortiz, C. Metallic Ions Released from Stainless Steel, Nickel-Free, and Titanium Orthodontic Alloys: Toxicity and DNA Damage. Am. J. Orthod. Dentofacial Orthop. 2011, 140, e115–e122. [Google Scholar] [CrossRef]
  15. McGinley, E.L.; Fleming, G.J.P.; Moran, G.P. Development of a Discriminatory Biocompatibility Testing Model for Non-Precious Dental Casting Alloys. Dent. Mater. 2011, 27, 1295–1306. [Google Scholar] [CrossRef] [PubMed]
  16. Pan, Y.; Jiang, L.; Lin, H.; Cheng, H. Cell Death Affected by Dental Alloys: Modes and Mechanisms. Dent. Mater. J. 2017, 36, 82–87. [Google Scholar] [CrossRef] [Green Version]
  17. Kovač, V.; Poljšak, B.; Primožič, J.; Jamnik, P. Are Metal Ions That Make up Orthodontic Alloys Cytotoxic, and Do They Induce Oxidative Stress in a Yeast Cell Model? Int. J. Mol. Sci. 2020, 21, 7993. [Google Scholar] [CrossRef]
  18. Rincic Mlinaric, M.; Durgo, K.; Katic, V.; Spalj, S. Cytotoxicity and Oxidative Stress Induced by Nickel and Titanium Ions from Dental Alloys on Cells of Gastrointestinal Tract. Toxicol. Appl. Pharmacol. 2019, 383, 114784. [Google Scholar] [CrossRef]
  19. Sardaro, N.; della Vella, F.; Incalza, M.A.; Stasio, D.D.I.; Lucchese, A.; Contaldo, M.; Laudadio, C.; Petruzzi, M. Oxidative Stress and Oral Mucosal Diseases: An Overview. In Vivo 2019, 33, 289–296. [Google Scholar] [CrossRef] [Green Version]
  20. Imirzalioglu, P.; Alaaddinoglu, E.; Yilmaz, Z.; Oduncuoglu, B.; Yilmaz, B.; Rosenstiel, S. Influence of Recasting Different Types of Dental Alloys on Gingival Fibroblast Cytotoxicity. J. Prosthet. Dent. 2012, 107, 24–33. [Google Scholar] [CrossRef]
  21. Noumbissi, S.; Scarano, A.; Gupta, S. A Literature Review Study on Atomic Ions Dissolution of Titanium and Its Alloys in Implant Dentistry. Materials 2019, 12, 368. [Google Scholar] [CrossRef] [PubMed]
  22. Kheder, W.; Al Kawas, S.; Khalaf, K.; Samsudin, A.R. Impact of Tribocorrosion and Titanium Particles Release on Dental Implant Complications—A Narrative Review. Jpn. Dent. Sci. Rev. 2021, 57, 182–189. [Google Scholar] [CrossRef] [PubMed]
  23. Loyola-Rodríguez, J.P.; Lastra-Corso, I.; García-Cortés, J.O.; Loyola-Leyva, A.; Domínguez-Pérez, R.A.; Avila-Arizmendi, D.; Contreras-Palma, G.; González-Calixto, C. In Vitro Determination of Genotoxicity Induced by Brackets Alloys in Cultures of Human Gingival Fibroblasts. J. Toxicol. 2020, 2020, 1467456. [Google Scholar] [CrossRef]
  24. Faccioni, F.; Franceschetti, P.; Cerpelloni, M.; Fracasso, M.E. In Vivo Study on Metal Release from Fixed Orthodontic Appliances and DNA Damage in Oral Mucosa Cells. Am. J. Orthod. Dentofac. Orthop. 2003, 124, 687–693. [Google Scholar] [CrossRef] [PubMed]
  25. Baričević, M.; Ratkaj, I.; Mladinić, M.; Želježić, D.; Kraljević, S.P.; Lončar, B.; Stipetić, M.M. In Vivo Assessment of DNA Damage Induced in Oral Mucosa Cells by Fixed and Removable Metal Prosthodontic Appliances. Clin. Oral Investig. 2012, 16, 325–331. [Google Scholar] [CrossRef] [PubMed]
  26. Alp, G.; Çakmak, G.; Sert, M.; Burgaz, Y. Corrosion Potential in Artificial Saliva and Possible Genotoxic and Cytotoxic Damage in Buccal Epithelial Cells of Patients Who Underwent Ni-Cr Based Porcelain-Fused-to-Metal Fixed Dental Prostheses. Mutat. Res. Genet. Toxicol. Environ. Mutagen. 2018, 827, 19–26. [Google Scholar] [CrossRef]
  27. Tomakidi, P.; Koke, U.; Kern, R.; Erdinger, L.; Krüger, H.; Kohl, A.; Komposch, G. Assessment of Acute Cyto- and Genotoxicity of Corrosion Eluates Obtained from Orthodontic Materials Using Monolayer Cultures of Immortalized Human Gingival Keratinocytes. J. Orofac. Orthop. 2000, 61, 2–19. [Google Scholar] [CrossRef]
  28. Angelieri, F.; Carlin, V.; Martins, R.A.; Ribeiro, D.A. Biomonitoring of Mutagenicity and Cytotoxicity in Patients Undergoing Fixed Orthodontic Therapy. Am. J. Orthod. Dentofacial Orthop. 2011, 139 (Suppl. 4), e399–e404. [Google Scholar] [CrossRef]
  29. Velasco-Ortega, E.; Jos, A.; Cameán, A.M.; Pato-Mourelo, J.; Segura-Egea, J.J. In Vitro Evaluation of Cytotoxicity and Genotoxicity of a Commercial Titanium Alloy for Dental Implantology. Mutat. Res. 2010, 702, 17–23. [Google Scholar] [CrossRef]
  30. Kitagawa, M.; Murakami, S.; Akashi, Y.; Oka, H.; Shintani, T.; Ogawa, I.; Inoue, T.; Kurihara, H. Current Status of Dental Metal Allergy in Japan. J. Prosthodont. Res. 2019, 63, 309–312. [Google Scholar] [CrossRef]
  31. Podzimek, S.; Tomka, M.; Sommerova, P.; Lyuya-Mi, Y.; Bartova, J.; Prochazkova, J. Immune Markers in Oral Discomfort Patients before and after Elimination of Oral Galvanism. Neuroendocrinol. Lett. 2013, 34, 802–808. [Google Scholar] [CrossRef] [PubMed]
  32. Venclíková, Z.; Benada, O.; Bártová, J.; Joska, L.; Mrklas, L.; Procházková, J.; Stejskal, V.; Podzimek, Š. In Vivo Effects of Dental Casting Alloys. Neuro Endocrinol. Lett. 2006, 27 (Suppl. 1), 61–68. [Google Scholar] [PubMed]
  33. Kerosuo, H.M.; Dahl, J.E. Adverse Patient Reactions during Orthodontic Treatment with Fixed Appliances. Am. J. Orthod. Dentofac. Orthop. 2007, 132, 789–795. [Google Scholar] [CrossRef] [PubMed]
  34. Balcheva, M.; Panov, V.; Krasteva, A.; Markova, M. Allergy to Dental Amalgam. J. Med. Dent. Pract. 2019, 6, 968–974. [Google Scholar] [CrossRef] [Green Version]
  35. de Morais, L.S.; Serra, G.G.; Albuquerque Palermo, E.F.; Andrade, L.R.; Müller, C.A.; Meyers, M.A.; Elias, C.N. Systemic Levels of Metallic Ions Released from Orthodontic Mini-Implants. Am. J. Orthod. Dentofacial Orthop. 2009, 135, 522–529. [Google Scholar] [CrossRef]
  36. El Sawy, A.A.; Shaarawy, M.A. Evaluation of Metal Ion Release from Ti6Al4V and Co-Cr-Mo Casting Alloys: In Vivo and In Vitro Study. J. Prosthodont. 2014, 23, 89–97. [Google Scholar] [CrossRef]
  37. Karnam, S.K.; Naveen Reddy, A.; Manjith, C.M. Comparison of Metal Ion Release from Different Bracket Archwire Combinations: An in Vitro Study. J. Contemp. Dent. Pract. 2012, 13, 376–381. [Google Scholar] [CrossRef]
  38. López-Alías, J.F.; Martinez-Gomis, J.; Anglada, J.M.; Peraire, M. Ion Release from Dental Casting Alloys as Assessed by a Continuous Flow System: Nutritional and Toxicological Implications. Dent. Mater. 2006, 22, 832–837. [Google Scholar] [CrossRef] [Green Version]
  39. Alnazzawi, A. Effect of Fixed Metallic Oral Appliances on Oral Health. J. Int. Soc. Prev. Community Dent. 2018, 8, 93. [Google Scholar] [CrossRef]
  40. Ayres, S. Sore Mouth Caused by Electrogalvanic Current. J. R. Soc. Med. 1984, 77, 708–709. [Google Scholar]
  41. Von Fraunhofer, J.A.; Staheli, P.J. The Measurement of Galvanic Corrosion Currents in Dental Amalgam. Corros. Sci. 1972, 12, 767–773. [Google Scholar] [CrossRef]
  42. Wartenberg, M.; Wirtz, N.; Grob, A.; Niedermeier, W.; Hescheler, J.; Peters, S.C.; Sauer, H. Direct Current Electrical Fields Induce Apoptosis in Oral Mucosa Cancer Cells by NADPH Oxidase-Derived Reactive Oxygen Species. Bioelectromagnetics 2008, 29, 47–54. [Google Scholar] [CrossRef] [PubMed]
  43. Korraah, A.; Odenthal, M.; Kopp, M.; Vigneswaran, N.; Sacks, P.G.; Dienes, H.P.; Stützer, H.; Niedermeier, W. Induction of Apoptosis and Up-Regulation of Cellular Proliferation in Oral Leukoplakia Cell Lines inside Electric Field. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. 2012, 113, 644–654. [Google Scholar] [CrossRef] [PubMed]
  44. Koch, P.; Bahmer, F.A. Oral Lesions and Symptoms Related to Metals Used in Dental Restorations: A Clinical, Allergological, and Histologic Study. J. Am. Acad. Dermatol. 1999, 41, 422–430. [Google Scholar] [CrossRef]
  45. Coculescu, E.C.; Tovaru, S.; Coculescu, B.I. Epidemiological and Etiological Aspects of Burning Mouth Syndrome. J. Med. Life 2014, 7, 305–309. [Google Scholar]
  46. Zakrzewska, J.; Buchanan, J.A.G. Burning Mouth Syndrome. BMJ Clin. Evid. 2016, 2016, 1307. [Google Scholar]
  47. Maltsman-Tseikhin, A.; Moricca, P.; Niv, D. Burning Mouth Syndrome: Will Better Understanding Yield Better Management? Pain Pract. 2007, 7, 151–162. [Google Scholar] [CrossRef]
  48. Minciullo, P.L.; Paolino, G.; Vacca, M.; Gangemi, S.; Nettis, E. Unmet Diagnostic Needs in Contact Oral Mucosal Allergies. Clin. Mol. Allergy 2016, 14, 10. [Google Scholar] [CrossRef] [Green Version]
  49. McParland, H.; Warnakulasuriya, S. Oral Lichenoid Contact Lesions to Mercury and Dental Amalgam—A Review. J. Biomed. Biotechnol. 2012, 2016, 589569. [Google Scholar] [CrossRef] [Green Version]
  50. Thornhill, M.H.; Pemberton, M.N.; Simmons, R.K.; Theaker, E.D. Amalgam-Contact Hypersensitivity Lesions and Oral Lichen Planus. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2003, 95, 291–299. [Google Scholar] [CrossRef]
  51. Schmidt-Westhausen, A.M. Oral Lichen Planus and Lichenoid Lesions: What’s New? Quintessence Int. 2020, 51, 156–161. [Google Scholar] [CrossRef] [PubMed]
  52. Laimer, J.; Henn, R.; Helten, T.; Sprung, S.; Zelger, B.; Zelger, B.; Steiner, R.; Schnabl, D.; Offermanns, V.; Bruckmoser, E.; et al. Amalgam Tattoo versus Melanocytic Neoplasm—Differential Diagnosis of Dark Pigmented Oral Mucosa Lesions Using Infrared Spectroscopy. PLoS ONE 2018, 13, e0207026. [Google Scholar] [CrossRef] [PubMed]
  53. Sutow, E.J.; Maillet, W.A.; Hall, G.C. Corrosion Potential Variation of Aged Dental Amalgam Restorations over Time. Dent. Mater. 2006, 22, 325–329. [Google Scholar] [CrossRef] [PubMed]
  54. Amano, H.; Tamura, A.; Yasuda, M.; Yamanaka, M.; Takeuchi, Y.; Sasaoka, K.; Yokoo, S.; Ishikawa, O. Amalgam Tattoo of the Oral Mucosa Mimics Malignant Melanoma. J. Dermatol. 2011, 38, 101–103. [Google Scholar] [CrossRef]
  55. Alawi, F. Pigmented Lesions of the Oral Cavity. An Update. Dent. Clin. N. Am. 2013, 57, 699–710. [Google Scholar] [CrossRef] [Green Version]
  56. Lambertini, M.; Patrizi, A.; Fanti, P.A.; Melotti, B.; Caliceti, U.; Magnoni, C.; Misciali, C.; Baraldi, C.; Ravaioli, G.M.; Dika, E. Oral Melanoma and Other Pigmentations: When to Biopsy? J. Eur. Acad. Dermatol. Venereol. 2018, 32, 209–214. [Google Scholar] [CrossRef]
  57. Vera-Kellet, C.; Del Barrio-Díaz, P. Oral Amalgam Tattoo Mimicking Melanoma. N. Engl. J. Med. 2016, 374, e21. [Google Scholar] [CrossRef] [Green Version]
  58. Gönen, Z.; Asan, C.Y.; Etöz, O.; Alkan, A. Oral Leukoplakia Associated with Amalgam Restorations. J. Oral Sci. 2016, 58, 445–448. [Google Scholar] [CrossRef] [Green Version]
  59. Holmstrup, P.; Vedtofte, P.; Reibel, J.; Stoltze, K. Long-Term Treatment Outcome of Oral Premalignant Lesions. Oral Oncol. 2006, 42, 461–474. [Google Scholar] [CrossRef]
  60. Pigatto, P.D.; Brambilla, L.; Ferrucci, S.M.; Ronchi, A.; Minoia, C.; Guzzi, G. Allergy and Adverse Reactions to Dental Amalgam: An Epidemiological Assessment. Contact Dermat. 2010, 63, 95. [Google Scholar]
  61. Muris, J.; Goossens, A.; Gonçalo, M.; Bircher, A.J.; Giménez-Arnau, A.; Foti, C.; Rustemeyer, T.; Feilzer, A.J.; Kleverlaan, C.J. Sensitization to Palladium and Nickel in Europe and the Relationship with Oral Disease and Dental Alloys. Contact Dermat. 2015, 72, 286–296. [Google Scholar] [CrossRef] [PubMed]
  62. Valentine-Thon, E.; Müller, K.; Guzzi, G.; Kreisel, S.; Ohnsorge, P.; Sandkamp, M. LTT-MELISA® Is Clinically Relevant for Detecting and Monitoring Metal Sensitivity. Neuroendocrinol. Lett. 2006, 27 (Suppl. 1), 17–24. [Google Scholar] [PubMed]
  63. Vrbova, R.; Podzimek, S.; Himmlova, L.; Roubickova, A.; Janovska, M.; Janatova, T.; Bartos, M.; Vinsu, A. Titanium and Other Metal Hypersensitivity Diagnosed by MELISA® Test: Follow-Up Study. Biomed Res. Int. 2021, 2021, 5512091. [Google Scholar] [CrossRef] [PubMed]
  64. Pföhler, C.; Vogt, T.; Müller, C.S.L. Kontaktallergische Gastritis: Seltene Manifestation Einer Metallallergie. Hautarzt 2016, 67, 359–364. [Google Scholar] [CrossRef]
  65. Zigante, M.; Rincic Mlinaric, M.; Kastelan, M.; Perkovic, V.; Trinajstic Zrinski, M.; Spalj, S. Symptoms of Titanium and Nickel Allergic Sensitization in Orthodontic Treatment. Prog. Orthod. 2020, 21, 17. [Google Scholar] [CrossRef]
  66. Pamphlett, R.; Kum Jew, S. Inorganic Mercury in Human Astrocytes, Oligodendrocytes, Corticomotoneurons and the Locus Ceruleus: Implications for Multiple Sclerosis, Neurodegenerative Disorders and Gliomas. BioMetals 2018, 31, 807–819. [Google Scholar] [CrossRef] [Green Version]
  67. Casetta, I.; Invernizzi, M.; Granieri, E. Multiple Sclerosis and Dental Amalgam: Case-Control Study in Ferrara, Italy. Neuroepidemiology 2001, 20, 134–137. [Google Scholar] [CrossRef]
  68. Bates, M.N.; Fawcett, J.; Garrett, N.; Cutress, T.; Kjellstrom, T. Health Effects of Dental Amalgam Exposure: A Retrospective Cohort Study. Int. J. Epidemiol. 2004, 33, 894–902. [Google Scholar] [CrossRef] [Green Version]
  69. Hsu, Y.C.; Chang, C.W.; Lee, H.L.; Chuang, C.C.; Chiu, H.C.; Li, W.Y.; Horng, J.T.; Fu, E. Association between History of Dental Amalgam Fillings and Risk of Parkinson’s Disease: A Population-Based Retrospective Cohort Study in Taiwan. PLoS ONE 2016, 11, e0166552. [Google Scholar] [CrossRef]
  70. Tseng, C.F.; Chen, K.H.; Yu, H.C.; Chang, Y.C. Association between Dental Amalgam Filling and Essential Tremor: A Nationwide Population-Based Case Control Study in Taiwan. Int. J. Environ. Res. Public Health 2020, 17, 780. [Google Scholar] [CrossRef] [Green Version]
  71. Tseng, C.F.; Chen, K.H.; Yu, H.C.; Huang, F.M.; Chang, Y.C. Dental Amalgam Fillings and Multiple Sclerosis: A Nationwide Population-Based Case-Control Study in Taiwan. Int. J. Environ. Res. Public Health 2020, 17, 2637. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  72. Gallusi, G.; Libonati, A.; Piro, M.; Di Taranto, V.; Montemurro, E.; Campanella, V. Is Dental Amalgam a Higher Risk Factor Rather than Resin-Based Restorations for Systemic Conditions? A Systematic Review. Materials 2021, 14, 1980. [Google Scholar] [CrossRef] [PubMed]
  73. Geier, D.A.; Geier, M.R. Dental Amalgam Fillings and Mercury Vapor Safety Limits in American Adults. Hum. Exp. Toxicol. 2022, 41, 9603271221106341. [Google Scholar] [CrossRef] [PubMed]
  74. Stejskal, V.; Hudecek, R.; Stejskal, J.; Sterzl, I. Diagnosis and Treatment of Metal-Induced Side-Effects. Neuroendocrinol. Lett. 2006, 27 (Suppl. 1), 7–16. [Google Scholar]
  75. Manousek, J.; Stejskal, V.; Kubena, P.; Jarkovsky, J.; Nemec, P.; Lokaj, P.; Dostalova, L.; Zadakova, A.; Pavlusova, M.; Benesova, K.; et al. Delayed-Type Hypersensitivity to Metals of Environmental Burden in Patients with Takotsubo Syndrome—Is There a Clinical Relevance? PLoS ONE 2016, 11, e0164786. [Google Scholar] [CrossRef] [Green Version]
  76. Sterzl, I.; Prochazkova, J.; Hrda, P.; Matucha, P.; Bartova, J.; Stejskal, V. Removal of Dental Amalgam Decreases Anti-TPO and Anti-Tg Autoantibodies in Patients with Autoimmune Thyroiditis. Neuroendocrinol. Lett. 2006, 27 (Suppl. 1), 25–30. [Google Scholar]
  77. Geier, D.A.; Geier, M.R. Dental Amalgams and the Incidence Rate of Arthritis among American Adults. Clin. Med. Insights Arthritis Musculoskelet. Disord. 2021, 14, 11795441211016260. [Google Scholar] [CrossRef]
  78. Rachmawati, D.; Muris, J.; Scheper, R.J.; Rustemeyer, T.; Kleverlaan, C.J.; Feilzer, A.J.; Von Blomberg, B.M.E.; Van Hoogstraten, I.M.W. Continuing the Quest for Autoimmunity Due to Oral Metal Exposure. Autoimmunity 2015, 48, 494–501. [Google Scholar] [CrossRef]
  79. Kisakol, G. Dental Amalgam Implantation and Thyroid Autoimmunity. Bratisl. Lek. Listy 2014, 115, 22–24. [Google Scholar] [CrossRef] [Green Version]
  80. Chen, K.-H.; Yu, H.-C.; Chang, Y.-C. Analysis of Dental Amalgam Fillings on Primary Sjögren’s Syndrome. Medicine 2021, 100, e28031. [Google Scholar] [CrossRef]
  81. Muller, A.W.J.; Loon, L.A.J.; Davidson, C.L. Electrical Potentials of Restorations in Subjects without Oral Complaints. J. Oral Rehabil. 1990, 17, 419–424. [Google Scholar] [CrossRef] [PubMed]
  82. Saǧlam, A.M.Ş.; Baysal, V.; Ceylan, A.M. Nickel and Cobalt Hypersensitive Reaction before and after Orthodontic Therapy in Children. J. Contemp. Dent. Pract. 2004, 5, 79–90. [Google Scholar] [CrossRef] [Green Version]
  83. Bilhan, H.; Bilgin, T.; Cakir, A.F.; Yuksel, B.; Von Fraunhofer, J.A. The Effect of Mucine, IgA, Urea, and Lysozyme on the Corrosion Behavior of Various Non-Precious Dental Alloys and Pure Titanium in Artificial Saliva. J. Biomater. Appl. 2007, 22, 197–221. [Google Scholar] [CrossRef] [PubMed]
  84. Mercieca, S.; Caligari Conti, M.; Buhagiar, J.; Camilleri, J. Assessment of Corrosion Resistance of Cast Cobalt- and Nickel-Chromium Dental Alloys in Acidic Environments. J. Appl. Biomater. Funct. Mater. 2018, 16, 47–54. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  85. Jirau-Colón, H.; González-Parrilla, L.; Martinez-Jiménez, J.; Adam, W.; Jiménez-Velez, B. Rethinking the Dental Amalgam Dilemma: An Integrated Toxicological Approach. Int. J. Environ. Res. Public Health 2019, 16, 1036. [Google Scholar] [CrossRef] [Green Version]
  86. Senkutvan, R.S.; Jacob, S.; Charles, A.; Vadgaonkar, V.; Jatol-Tekade, S.; Gangurde, P. Evaluation of Nickel Ion Release from Various Orthodontic Arch Wires: An in Vitro Study. J. Int. Soc. Prev. Community Dent. 2014, 4, 12. [Google Scholar] [CrossRef] [Green Version]
  87. Kassapidou, M.; Hjalmarsson, L.; Johansson, C.B.; Hammarström Johansson, P.; Morisbak, E.; Wennerberg, A.; Franke Stenport, V. Cobalt-Chromium Alloys Fabricated with Four Different Techniques: Ion Release, Toxicity of Released Elements and Surface Roughness. Dent. Mater. 2020, 36, e352–e363. [Google Scholar] [CrossRef]
  88. Sarraf, M.; Rezvani Ghomi, E.; Alipour, S.; Ramakrishna, S.; Liana Sukiman, N. A State-of-the-Art Review of the Fabrication and Characteristics of Titanium and Its Alloys for Biomedical Applications. Bio-Des. Manuf. 2022, 5, 371. [Google Scholar] [CrossRef]
  89. Nagay, B.E.; Cordeiro, J.M.; Barao, V.A.R. Insight into Corrosion of Dental Implants: From Biochemical Mechanisms to Designing Corrosion-Resistant Materials. Curr. Oral Heal. Rep. 2022, 9, 7. [Google Scholar] [CrossRef]
  90. Cordeiro, J.M.; Barão, V.A.R. Is There Scientific Evidence Favoring the Substitution of Commercially Pure Titanium with Titanium Alloys for the Manufacture of Dental Implants? Mater. Sci. Eng. C Mater. Biol. Appl. 2017, 71, 1201–1215. [Google Scholar] [CrossRef]
  91. Sedarat, C.; Harmand, M.F.; Naji, A.; Nowzari, H. In Vitro Kinetic Evaluation of Titanium Alloy Biodegradation. J. Periodontal Res. 2001, 36, 269–274. [Google Scholar] [CrossRef] [PubMed]
  92. Costa, B.C.; Tokuhara, C.K.; Rocha, L.A.; Oliveira, R.C.; Lisboa-Filho, P.N.; Costa Pessoa, J. Vanadium Ionic Species from Degradation of Ti-6Al-4V Metallic Implants: In Vitro Cytotoxicity and Speciation Evaluation. Mater. Sci. Eng. C 2019, 96, 730–739. [Google Scholar] [CrossRef] [PubMed]
  93. van Vuuren, L.J.; Odendaal, J.S.; Pistorius, P.C. Galvanic Corrosion of Dental Cobalt-Chromium Alloys and Dental Amalgam in Artificial Saliva. SADJ 2008, 63, 034–038. [Google Scholar]
  94. Ciszewski, A.; Baraniak, M.; Urbanek-Brychczyńska, M. Corrosion by Galvanic Coupling between Amalgam and Different Chromium-Based Alloys. Dent. Mater. 2007, 23, 1256–1261. [Google Scholar] [CrossRef] [PubMed]
  95. Taher, N.M.; Al Jabab, A.S. Galvanic Corrosion Behavior of Implant Suprastructure Dental Alloys. Dent. Mater. 2003, 19, 54–59. [Google Scholar] [CrossRef]
  96. Iijima, M.; Endo, K.; Yuasa, T.; Ohno, H.; Hayashi, K.; Kakizaki, M.; Mizoguchi, I. Galvanic Corrosion Behavior of Orthodontic Archwire Alloys Coupled to Bracket Alloys. Angle Orthod. 2006, 76, 705–711. [Google Scholar] [CrossRef]
  97. Nayak, R.S.; Shafiuddin, B.; Pasha, A.; Vinay, K.; Narayan, A.; Shetty, S.V. Comparison of Galvanic Currents Generated Between Different Combinations of Orthodontic Brackets and Archwires Using Potentiostat: An In Vitro Study. J. Int. Oral Health 2015, 7, 29–35. [Google Scholar] [PubMed]
  98. Oh, K.T.; Kim, K.N. Electrochemical Properties of Suprastructures Galvanically Coupled to a Titanium Implant. J. Biomed. Mater. Res. Part B Appl. Biomater. 2004, 70, 318–331. [Google Scholar] [CrossRef] [PubMed]
  99. Soares, F.M.S.; Elias, C.N.; Monteiro, E.S.; Coimbra, M.E.R.; Santana, A.I.C. Galvanic Corrosion of Ti Dental Implants Coupled to CoCrMo Prosthetic Component. Int. J. Biomater. 2021, 2021, 1313343. [Google Scholar] [CrossRef] [PubMed]
  100. Mellado-Valero, A.; Muñoz, A.I.; Pina, V.G.; Sola-Ruiz, M.F. Electrochemical Behaviour and Galvanic Effects of Titanium Implants Coupled to Metallic Suprastructures in Artificial Saliva. Materials 2018, 11, 171. [Google Scholar] [CrossRef] [Green Version]
  101. Amine, M.; Merdma, W.; El Boussiri, K. Electrogalvanism in Oral Implantology: A Systematic Review. Int. J. Dent. 2022, 2022, 4575416. [Google Scholar] [CrossRef]
  102. Sikora, C.L.; Alfaro, M.F.; Yuan, J.C.C.; Barao, V.A.; Sukotjo, C.; Mathew, M.T. Wear and Corrosion Interactions at the Titanium/Zirconia Interface: Dental Implant Application. J. Prosthodont. 2018, 27, 842–852. [Google Scholar] [CrossRef] [PubMed]
  103. ISO 10271:2020; Dentistry—Corrosion Test Methods for Metallic Materials. ISO: Geneva, Switzerland, 2020. Available online: https://www.iso.org/standard/73445.html (accessed on 17 October 2022).
  104. Barão, V.A.R.; Ramachandran, R.A.; Matos, A.O.; Badhe, R.V.; Grandini, C.R.; Sukotjo, C.; Ozevin, D.; Mathew, M. Prediction of Tribocorrosion Processes in Titanium-Based Dental Implants Using Acoustic Emission Technique: Initial Outcome. Mater. Sci. Eng. C Mater. Biol. Appl. 2021, 123, 112000. [Google Scholar] [CrossRef] [PubMed]
  105. Elshahawy, W.M.; Watanabe, I.; Kramer, P. In Vitro Cytotoxicity Evaluation of Elemental Ions Released from Different Prosthodontic Materials. Dent. Mater. 2009, 25, 1551–1555. [Google Scholar] [CrossRef]
  106. Genchi, G.; Carocci, A.; Lauria, G.; Sinicropi, M.S.; Catalano, A. Nickel: Human Health and Environmental Toxicology. Int. J. Environ. Res. Public Health 2020, 17, 679. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  107. Fage, S.W.; Muris, J.; Jakobsen, S.S.; Thyssen, J.P. Titanium: A Review on Exposure, Release, Penetration, Allergy, Epidemiology, and Clinical Reactivity. Contact Dermat. 2016, 74, 323–345. [Google Scholar] [CrossRef] [Green Version]
  108. ISO 7405:2018; Dentistry—Evaluation of Biocompatibility of Medical Devices used in Dentistry. ISO: Geneva, Switzerland, 2018. Available online: https://www.iso.org/standard/71503.html (accessed on 17 October 2022).
  109. Klausner, M.; Handa, Y.; Aizawa, S. In Vitro Three-Dimensional Organotypic Culture Models of the Oral Mucosa. Vitr. Cell. Dev. Biol. Anim. 2021, 57, 148–159. [Google Scholar] [CrossRef]
  110. Rahimi, C.; Rahimi, B.; Padova, D.; Rooholghodos, S.A.; Bienek, D.R.; Luo, X.; Kaufman, G.; Raub, C.B. Oral Mucosa-on-a-Chip to Assess Layer-Specific Responses to Bacteria and Dental Materials. Biomicrofluidics 2018, 12, 054106. [Google Scholar] [CrossRef]
  111. Koning, J.J.; Rodrigues Neves, C.T.; Schimek, K.; Thon, M.; Spiekstra, S.W.; Waaijman, T.; de Gruijl, T.D.; Gibbs, S. A Multi-Organ-on-Chip Approach to Investigate How Oral Exposure to Metals Can Cause Systemic Toxicity Leading to Langerhans Cell Activation in Skin. Front. Toxicol. 2022, 3, 824825. [Google Scholar] [CrossRef]
  112. Lu, Y.P.; Huang, J.W.; Lee, I.N.; Weng, R.C.; Lin, M.Y.; Yang, J.T.; Lin, C.T. A Portable System to Monitor Saliva Conductivity for Dehydration Diagnosis and Kidney Healthcare. Sci. Rep. 2019, 9, 14771. [Google Scholar] [CrossRef] [Green Version]
  113. Spirk, C.; Hartl, S.; Pritz, E.; Gugatschka, M.; Kolb-Lenz, D.; Leitinger, G.; Roblegg, E. Comprehensive Investigation of Saliva Replacement Liquids for the Treatment of Xerostomia. Int. J. Pharm. 2019, 571, 118759. [Google Scholar] [CrossRef] [PubMed]
  114. Winter, C.; Keimel, R.; Gugatschka, M.; Kolb, D.; Leitinger, G.; Roblegg, E. Investigation of Changes in Saliva in Radiotherapy-Induced Head Neck Cancer Patients. Int. J. Environ. Res. Public Health 2021, 18, 1629. [Google Scholar] [CrossRef]
  115. Xu, F.; Laguna, L.; Sarkar, A. Aging-Related Changes in Quantity and Quality of Saliva: Where Do We Stand in Our Understanding? J. Texture Stud. 2019, 50, 27–35. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  116. Bel’skaya, L.V.; Kosenok, V.K.; Sarf, E.A. Chronophysiological Features of the Normal Mineral Composition of Human Saliva. Arch. Oral Biol. 2017, 82, 286–292. [Google Scholar] [CrossRef] [PubMed]
  117. Saibaba, G.; Srinivasan, M.; Priya Aarthy, A.; Silambarasan, V.; Archunan, G. Ultrastructural and Physico-Chemical Characterization of Saliva during Menstrual Cycle in Perspective of Ovulation in Human. Drug Discov. Ther. 2017, 11, 91–97. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  118. Thomas, A.; Sridhar, S.; Aghyarian, S.; Watkins-Curry, P.; Chan, J.Y.; Pozzi, A.; Rodrigues, D.C. Corrosion Behavior of Zirconia in Acidulated Phosphate Fluoride. J. Appl. Oral Sci. 2016, 24, 52–60. [Google Scholar] [CrossRef]
  119. Koppolu, P.; Sirisha, S.; Penala, S.; Reddy, P.K.; Alotaibi, D.H.; Abusalim, G.S.; Lingam, A.S.; Mukhtar, A.H.; Barakat, A.; Almokhatieb, A.A. Correlation of Blood and Salivary PH Levels in Healthy, Gingivitis, and Periodontitis Patients before and after Non-Surgical Periodontal Therapy. Diagnostics 2022, 12, 97. [Google Scholar] [CrossRef]
  120. Ferrer, M.D.; Pérez, S.; Lopez, A.L.; Sanz, J.L.; Melo, M.; Llena, C.; Mira, A. Evaluation of Clinical, Biochemical and Microbiological Markers Related to Dental Caries. Int. J. Environ. Res. Public Health 2021, 18, 6049. [Google Scholar] [CrossRef]
  121. Borg, W.; Cassar, G.; Camilleri, L.; Attard, N.; Camilleri, J. Surface Microstructural Changes and Release of Ions from Dental Metal Alloy Removable Prostheses in Patients Suffering from Acid Reflux. J. Prosthodont. 2018, 27, 115–119. [Google Scholar] [CrossRef]
  122. Dosedělová, V.; Ďurč, P.; Dolina, J.; Konečný, Š.; Foret, F.; Kubáň, P. Analysis of Bicarbonate, Phosphate and Other Anions in Saliva by Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection in Diagnostics of Gastroesophageal Reflux Disease. Electrophoresis 2020, 41, 116–122. [Google Scholar] [CrossRef]
  123. Muralidharan, D.; Fareed, N.; Pradeep, P.V.; Margabandhu, S.; Ramalingam, K.; Ajith Kumar, B.V. Qualitative and Quantitative Changes in Saliva among Patients with Thyroid Dysfunction Prior to and Following the Treatment of the Dysfunction. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. 2013, 115, 617–623. [Google Scholar] [CrossRef] [PubMed]
  124. Marín Martínez, L.; Molino Pagán, D.; López Jornet, P. Trace Elements in Saliva as Markers of Type 2 Diabetes Mellitus. Biol. Trace Elem. Res. 2018, 186, 354–360. [Google Scholar] [CrossRef] [PubMed]
  125. Quade, B.N.; Parker, M.D.; Occhipinti, R. The Therapeutic Importance of Acid-Base Balance. Biochem. Pharmacol. 2021, 183, 114278. [Google Scholar] [CrossRef] [PubMed]
  126. Rahiotis, C.; Petraki, V.; Mitrou, P. Changes in Saliva Characteristics and Carious Status Related to Metabolic Control in Patients with Type 2 Diabetes Mellitus. J. Dent. 2021, 108, 103629. [Google Scholar] [CrossRef]
  127. Geckili, O.; Bilhan, H.; Bilgin, T.; Von Fraunhofer, J.A. The Effect of Urea on the Corrosion Behavior of Different Dental Alloys. Indian J. Dent. Res. 2012, 23, 75. [Google Scholar] [CrossRef]
  128. Teixeira, H.; Branco, A.C.; Rodrigues, I.; Silva, D.; Cardoso, S.; Colaço, R.; Serro, A.P.; Figueiredo-Pina, C.G. Effect of Albumin, Urea, Lysozyme and Mucin on the Triboactivity of Ti6Al4V/Zirconia Pair Used in Dental Implants. J. Mech. Behav. Biomed. Mater. 2021, 118, 104451. [Google Scholar] [CrossRef]
  129. Zhang, X.; Wei, L.-C.; Wu, B.; Yu, L.-Y.; Wang, X.-P.; Liu, Y. A Comparative Analysis of Metal Allergens Associated with Dental Alloy Prostheses and the Expression of HLA-DR in Gingival Tissue. Mol. Med. Rep. 2016, 13, 91–98. [Google Scholar] [CrossRef] [Green Version]
  130. McGinley, E.L.; Dowling, A.H.; Moran, G.P.; Fleming, G.J.P. Influence of S. Mutans on Base-Metal Dental Casting Alloy Toxicity. J. Dent. Res. 2013, 92, 92–97. [Google Scholar] [CrossRef]
  131. Mystkowska, J.; Niemirowicz-Laskowska, K.; Łysik, D.; Tokajuk, G.; Dąbrowski, J.R.; Bucki, R. The Role of Oral Cavity Biofilm on Metallic Biomaterial Surface Destruction–Corrosion and Friction Aspects. Int. J. Mol. Sci. 2018, 19, 743. [Google Scholar] [CrossRef] [Green Version]
  132. Mathew, M.T.; Barão, V.A.; Yuan, J.C.C.; Assunção, W.G.; Sukotjo, C.; Wimmer, M.A. What Is the Role of Lipopolysaccharide on the Tribocorrosive Behavior of Titanium? J. Mech. Behav. Biomed. Mater. 2012, 8, 71–85. [Google Scholar] [CrossRef]
  133. Figueiredo-Pina, C.G.; Guedes, M.; Sequeira, J.; Pinto, D.; Bernardo, N.; Carneiro, C. On the Influence of Streptococcus Salivarius on the Wear Response of Dental Implants: An in Vitro Study. J. Biomed. Mater. Res. Part B Appl. Biomater. 2019, 107, 1393–1399. [Google Scholar] [CrossRef] [PubMed]
  134. Fais, L.M.G.; Fernandes-Filho, R.B.; Pereira-Da-Silva, M.A.; Vaz, L.G.; Adabo, G.L. Titanium Surface Topography after Brushing with Fluoride and Fluoride-Free Toothpaste Simulating 10 Years of Use. J. Dent. 2012, 40, 265–275. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  135. Faria, A.C.L.; de Bordin, A.R.V.; Pedrazzi, V.; Rodrigues, R.C.S.; Ribeiro, R.F. Effect of Whitening Toothpaste on Titanium and Titanium Alloy Surfaces. Braz. Oral Res. 2012, 26, 498–504. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  136. Nogués, L.; Martinez-Gomis, J.; Molina, C.; Peraire, M.; Salsench, J.; Sevilla, P.; Gil, F.J. Dental Casting Alloys Behaviour during Power Toothbrushing with Toothpastes with Various Abrasivities. Part I: Wear Behavior. J. Mater. Sci. Mater. Med. 2008, 19, 3041–3048. [Google Scholar] [CrossRef] [Green Version]
  137. Shuto, T.; Mine, Y.; Makihira, S.; Nikawa, H.; Wachi, T.; Kakimoto, K. Alterations to Titanium Surface Depending on the Fluorides and Abrasives in Toothpaste. Materials 2021, 15, 51. [Google Scholar] [CrossRef]
  138. Anwar, E.M.; Kheiralla, L.S.; Tammam, R.H. Effect of Fluoride on the Corrosion Behavior of Ti and Ti6Al4V Dental Implants Coupled with Different Superstructures. J. Oral Implantol. 2011, 37, 309–317. [Google Scholar] [CrossRef]
  139. Erdogan, A.T.; Nalbantgil, D.; Ulkur, F.; Sahin, F. Metal Ion Release from Silver Soldering and Laser Welding Caused by Different Types of Mouthwash. Angle Orthod. 2015, 85, 665–672. [Google Scholar] [CrossRef]
  140. Polychronis, G.; Al Jabbari, Y.S.; Eliades, T.; Zinelis, S. Galvanic Coupling of Steel and Gold Alloy Lingual Brackets with Orthodontic Wires: Is Corrosion a Concern? Angle Orthod. 2018, 88, 450–457. [Google Scholar] [CrossRef]
  141. Jafari, K.; Rahimzadeh, S.; Hekmatfar, S. Nickel Ion Release from Dental Alloys in Two Different Mouthwashes. J. Dent. Res. Dent. Clin. Dent. Prospect. 2019, 13, 19–23. [Google Scholar] [CrossRef] [Green Version]
  142. Rincic Mlinaric, M.; Karlovic, S.; Ciganj, Z.; Acev, D.P.; Pavlic, A.; Spalj, S. Oral Antiseptics and Nickel-Titanium Alloys: Mechanical and Chemical Effects of Interaction. Odontology 2019, 107, 150–157. [Google Scholar] [CrossRef]
  143. Pavlic, A.; Perissinotto, F.; Turco, G.; Contardo, L.; Stjepan, S. Do Chlorhexidine and Probiotics Solutions Provoke Corrosion of Orthodontic Mini-Implants? An In Vitro Study. Int. J. Oral Maxillofac. Implant. 2019, 33, 1379–1388. [Google Scholar] [CrossRef] [PubMed]
  144. Pupim, D.; Peixoto, R.F.; MacEdo, A.P.; Palma-Dibb, R.G.; De Mattos, M.D.G.C.; Galo, R. Influence of the Commercial Mouthwashes on the Corrosion Behaviour of Dental Alloy. Mater. Res. 2022, 25, e20210385. [Google Scholar] [CrossRef]
  145. Shahabi, M.; Jahanbin, A.; Esmaily, H.; Sharifi, H.; Salari, S. Comparison of Some Dietary Habits on Corrosion Behavior of Stainless Steel Brackets: An in Vitro Study. J. Clin. Pediatr. Dent. 2011, 35, 429–432. [Google Scholar] [CrossRef]
  146. Rachmawati, D.; Cahyasari, D.A.; Febiantama, A.T.; Hidayati, L.; Kleverlaan, C.J. Brewed Robusta Coffee Increases Nickel Ion Release from Dental Alloys: An In Vitro Study. Materials 2021, 14, 7069. [Google Scholar] [CrossRef]
  147. Parenti, S.I.; Guicciardi, S.; Melandri, C.; Sprio, S.; Lafratta, E.; Tampieri, A.; Bonetti, G.A. Effect of Soft Drinks on the Physical and Chemical Features of Nickel-Titanium-Based Orthodontic Wires. Acta Odontol. Scand. 2012, 70, 49–55. [Google Scholar] [CrossRef] [PubMed]
  148. Liu, Q.; Zhao, M.; Chen, W.; Xu, K.; Huang, F.; Qu, J.; Xu, Z.; Wang, X.; Wang, Y.; Zhu, Y.; et al. Mainstream Cigarette Smoke Induces Autophagy and Promotes Apoptosis in Oral Mucosal Epithelial Cells. Arch. Oral Biol. 2020, 111, 104646. [Google Scholar] [CrossRef] [PubMed]
  149. Balaji, S. Tobacco Smoking and Surgical Healing of Oral Tissues: A Review. Indian J. Dent. Res. 2008, 19, 344–348. [Google Scholar] [CrossRef] [PubMed]
  150. Yildirim, S.Y.; Degirmenci, N.; Tugrul, S.; Ozturan, O. Effects of Smoking on Healthy Oral Mucosa: A Red-Green-Blue (Photographic) Evaluation. Mater. Res. 2017, 13 (Suppl. 27), 9–13. [Google Scholar]
  151. Yagyuu, T.; Funayama, N.; Imada, M.; Kirita, T. Effect of Smoking Status and Programmed Death-Ligand 1 Expression on the Microenvironment and Malignant Transformation of Oral Leukoplakia: A Retrospective Cohort Study. PLoS ONE 2021, 16, e0250359. [Google Scholar] [CrossRef]
  152. dos Santos Maidana, M.; Varela Junior, A.S.; Corcini, C.D.; Pereira, J.R.; Pires, D.M.; Tavella, R.A.; Fernandes, C.L.F.; dos Santos, M.; Garcia, E.M.; da Silva Júnior, F.M.R. Oral Cytological Changes in Young Adults Related to Alcohol Consumption. Arch. Oral Biol. 2021, 126, 105127. [Google Scholar] [CrossRef]
  153. Vassoler, T.; Dogenski, L.C.; Sartori, V.K.; Presotto, J.S.; Cardoso, M.Z.; Zandoná, J.; Trentin, M.S.; Linden, M.S.; Palhano, H.S.; Vargas, J.E.; et al. Evaluation of the Genotoxicity of Tobacco and Alcohol in Oral Mucosa Cells: A Pilot Study. J. Contemp. Dent. Pract. 2021, 22, 745–750. [Google Scholar] [CrossRef] [PubMed]
  154. Saluja, P.; Shetty, V.; Dave, A.; Arora, M.; Hans, V.; Madan, A. Comparative Evaluation of the Effect of Menstruation, Pregnancy and Menopause on Salivary Flow Rate, PH and Gustatory Function. J. Clin. Diagn. Res. 2014, 8, ZC81. [Google Scholar] [CrossRef] [PubMed]
  155. Mahesh, D.R.; Komali, G.; Jayanthi, K.; Dinesh, D.; Saikavitha, T.V.; Dinesh, P. Evaluation of Salivary Flow Rate, PH and Buffer in Pre, Post & Post Menopausal Women on HRT. J. Clin. Diagn. Res. 2014, 8, 233–236. [Google Scholar] [CrossRef]
  156. Ciesielska, A.; Kusiak, A.; Ossowska, A.; Grzybowska, M.E. Changes in the Oral Cavity in Menopausal Women—A Narrative Review. Int. J. Environ. Res. Public Health 2022, 19, 253. [Google Scholar] [CrossRef]
  157. Okada, S.; Iwata, K.; Katagiri, A. Pathognomonic Hypersensitivity of the Oral Mucosa and Tongue Induced by Diabetes Mellitus Accompanied by Saliva Reduction in Rats. J. Oral Facial Pain Headache 2021, 35, 54–61. [Google Scholar] [CrossRef]
  158. Marín-Martínez, L.; Molino-Pagán, D.; López-Jornet, P. Trace Elements in Saliva and Plasma of Patients with Type 2 Diabetes: Association to Metabolic Control and Complications. Diabetes Res. Clin. Pract. 2019, 157, 107871. [Google Scholar] [CrossRef]
  159. Femiano, F.; Gombos, F.; Esposito, V.; Nunziata, M.; Scully, C. Burning Mouth Syndrome (BMS): Evaluation of Thyroid and Taste. Med. Oral Patol. Oral Cir. Bucal 2006, 11, 22–25. [Google Scholar]
  160. Femiano, F.; Lanza, A.; Buonaiuto, C.; Gombos, F.; Nunziata, M.; Cuccurullo, L.; Cirillo, N. Burning Mouth Syndrome and Burning Mouth in Hypothyroidism: Proposal for a Diagnostic and Therapeutic Protocol. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endodontol. 2008, 105, e22–e27. [Google Scholar] [CrossRef]
  161. Stejskal, V.; Reynolds, T.; Bjørklund, G. Increased Frequency of Delayed Type Hypersensitivity to Metals in Patients with Connective Tissue Disease. J. Trace Elem. Med. Biol. 2015, 31, 230–236. [Google Scholar] [CrossRef]
  162. Louise McGinley, E.; Coleman, D.C.; Moran, G.P.; Fleming, G.J.P. Effects of Surface Finishing Conditions on the Biocompatibility of a Nickel-Chromium Dental Casting Alloy. Dent. Mater. 2011, 27, 637–650. [Google Scholar] [CrossRef]
  163. Moslehifard, E.; Ghaffari, T.; Mohammadian-Navid, S.; Ghafari-Nia, M.; Farmani, A.; Nasirpouri, F. Effect of Chemical Passivation on Corrosion Behavior and Ion Release of a Commercial Chromium-Cobalt Alloy. J. Dent. Res. Dent. Clin. Dent. Prospect. 2020, 14, 171–176. [Google Scholar] [CrossRef] [PubMed]
  164. Verdeguer, P.; Gil, J.; Punset, M.; Manero, J.M.; Nart, J.; Vilarrasa, J.; Ruperez, E. Citric Acid in the Passivation of Titanium Dental Implants: Corrosion Resistance and Bactericide Behavior. Materials 2022, 15, 545. [Google Scholar] [CrossRef] [PubMed]
  165. Prando, D.; Brenna, A.; Diamanti, M.V.; Beretta, S.; Bolzoni, F.; Ormellese, M.; Pedeferri, M.P. Corrosion of Titanium: Part 2: Effects of Surface Treatments. J. Appl. Biomater. Funct. Mater. 2018, 16, 3–13. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  166. Xuereb, M.; Camilleri, J.; Attard, N. Systematic Review of Current Dental Implant Coating Materials and Novel Coating Techniques. Int. J. Prosthodont. 2015, 28, 51–59. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  167. Lu, T.; Qiao, Y.; Liu, X. Surface Modification of Biomaterials Using Plasma Immersion Ion Implantation and Deposition. Interface Focus 2012, 2, 325–336. [Google Scholar] [CrossRef] [Green Version]
  168. Li, Q.; Li, L.; Zhao, M.; Dong, L.; Wu, J.; Li, D. Biological Actions of Cu/Zn Coimplanted TiN on Ti-6Al-4V Alloy. Biointerphases 2019, 14, 051008. [Google Scholar] [CrossRef]
  169. Shi, Q.; Qian, Z.; Liu, D.; Liu, H. Surface Modification of Dental Titanium Implant by Layer-by-Layer Electrostatic Self-Assembly. Front. Physiol. 2017, 8, 574. [Google Scholar] [CrossRef] [Green Version]
  170. Mistry, S.; Roy, R.; Kundu, B.; Datta, S.; Kumar, M.; Chanda, A.; Kundu, D. Clinical Outcome of Hydroxyapatite Coated, Bioactive Glass Coated, and Machined Ti6Al4V Threaded Dental Implant in Human Jaws: A Short-Term Comparative Study. Implant Dent. 2016, 25, 252–260. [Google Scholar] [CrossRef]
  171. Velloso, G.; Moraschini, V.; dos Santos Porto Barboza, E. Hydrophilic Modification of Sandblasted and Acid-Etched Implants Improves Stability during Early Healing: A Human Double-Blind Randomized Controlled Trial. Int. J. Oral Maxillofac. Surg. 2019, 48, 684–690. [Google Scholar] [CrossRef]
  172. Kunrath, M.F.; Muradás, T.C.; Penha, N.; Campos, M.M. Innovative Surfaces and Alloys for Dental Implants: What about Biointerface-Safety Concerns? Dent. Mater. 2021, 37, 1447–1462. [Google Scholar] [CrossRef]
  173. Raap, U.; Stiesch, M.; Kapp, A. Contact Allergy to Dental Materials. JDDG J. Dtsch. Dermatol. Ges. 2012, 10, 391–396. [Google Scholar] [CrossRef] [PubMed]
  174. Sutow, E.J.; Maillet, W.A.; Taylor, J.C.; Hall, G.C. In Vivo Galvanic Currents of Intermittently Contacting Dental Amalgam and Other Metallic Restorations. Dent. Mater. 2004, 20, 823–831. [Google Scholar] [CrossRef] [PubMed]
  175. Procházková, J.; Podzimek, Š.; Tomka, M.; Kučerová, H.; Mihaljevič, M.; Hána, K.; Mikšovský, M.; Šterzl, I.; Vinšová, J. Metal Alloys in the Oral Cavity as a Cause of Oral Discomfort in Sensitive Patients. Neuroendocrinol. Lett. 2006, 27 (Suppl. 1), 53–58. [Google Scholar] [PubMed]
Materials 15 07476 g001 550
Figure 1. Interactions of dental alloys with the oral environment. The dental alloys are affected by intraoral (saliva, oral biofilm) and extraoral (food, drinks, oral hygiene, etc.) factors, which lead to chemical corrosion. Moreover, metallic appliances produced from different dental alloys in the oral environment may have galvanic interaction. In addition to that, the components of dental implants form a tribosystem where corrosion and wear are combined.
Figure 1. Interactions of dental alloys with the oral environment. The dental alloys are affected by intraoral (saliva, oral biofilm) and extraoral (food, drinks, oral hygiene, etc.) factors, which lead to chemical corrosion. Moreover, metallic appliances produced from different dental alloys in the oral environment may have galvanic interaction. In addition to that, the components of dental implants form a tribosystem where corrosion and wear are combined.
Materials 15 07476 g001
Materials 15 07476 g002 550
Figure 2. Local and systemic effects of dental alloys. Metal ions released from the dental alloys accumulate in the oral mucosa, causing its pigmentation or chronic inflammatory reactions. In allergic patients, metal ions may cause Type IV hypersensitivity, mostly affecting skin and oral mucosa. Moreover, hypersensitivity to metals may aggravate autoimmune diseases affecting joints, skin, and salivary glands.
Figure 2. Local and systemic effects of dental alloys. Metal ions released from the dental alloys accumulate in the oral mucosa, causing its pigmentation or chronic inflammatory reactions. In allergic patients, metal ions may cause Type IV hypersensitivity, mostly affecting skin and oral mucosa. Moreover, hypersensitivity to metals may aggravate autoimmune diseases affecting joints, skin, and salivary glands.
Materials 15 07476 g002
Materials 15 07476 g003a 550Materials 15 07476 g003b 550
Figure 3. The most common oral lesions that may be associated with dental alloys: (a)—oral lichen planus; (b)—oral mucosa pigmentation; (c)—oral leukoplakia; (d)—recurrent aphthous stomatitis.
Figure 3. The most common oral lesions that may be associated with dental alloys: (a)—oral lichen planus; (b)—oral mucosa pigmentation; (c)—oral leukoplakia; (d)—recurrent aphthous stomatitis.
Materials 15 07476 g003aMaterials 15 07476 g003b
Materials 15 07476 g004 550
Figure 4. Decision tree for diagnosis and management of conditions potentially associated with dental alloys.
Figure 4. Decision tree for diagnosis and management of conditions potentially associated with dental alloys.
Materials 15 07476 g004
Table
Table 1. Factors increasing the risk of adverse effects associated with dental alloys.
Table 1. Factors increasing the risk of adverse effects associated with dental alloys.
Risk FactorsMechanism of Action
Local factorsUse of dental alloys with low corrosion resistanceIncreased release of metal ions
Galvanic coupling of different dental alloys in the oral cavityIncreased release of metal ions, chronic irritation of the oral mucosa with the direct current
Poor oral hygieneIncreased corrosion due to acidogenic flora activity
Multiple caries
Periodontal disease		Decreased salivary pH and increased corrosion
Fluoride-containing oral hygiene productsThe increase in galvanic current and corrosion
Ethanol-based oral rinsesThe increase in galvanic current and corrosion
Abrasive toothpastesSurface degradation of dental alloys
Habitual factorsSmoking and hard alcohol consumptionDecreased resistance and healing potential of the oral mucosa
Regular intake of acidic foods and drinksThe increase in galvanic current and corrosion
Systemic factorsRadiotherapyDecreased resistance and healing potential of the oral mucosa, decreased salivary pH
Gastro-intestinal reflux diseaseThe increase in galvanic current and corrosion
Post-menopausal period in women
Diabetes mellitus
Thyroid hypofunction		Decreased salivary pH, altered taste, increased sensitivity of the oral mucosa
Renal diseaseIncreased electroconductivity of the whole saliva
Autoimmune diseasesPotential hypersensitivity to metals
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Arakelyan, M.; Spagnuolo, G.; Iaculli, F.; Dikopova, N.; Antoshin, A.; Timashev, P.; Turkina, A. Minimization of Adverse Effects Associated with Dental Alloys. Materials 2022, 15, 7476. https://doi.org/10.3390/ma15217476

AMA Style

Arakelyan M, Spagnuolo G, Iaculli F, Dikopova N, Antoshin A, Timashev P, Turkina A. Minimization of Adverse Effects Associated with Dental Alloys. Materials. 2022; 15(21):7476. https://doi.org/10.3390/ma15217476

Chicago/Turabian Style

Arakelyan, Marianna, Gianrico Spagnuolo, Flavia Iaculli, Natalya Dikopova, Artem Antoshin, Peter Timashev, and Anna Turkina. 2022. "Minimization of Adverse Effects Associated with Dental Alloys" Materials 15, no. 21: 7476. https://doi.org/10.3390/ma15217476

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop