knowledge about the Biocompatibility of Dental alloys used in fabrication of Dental Crowns are of great importance to Patients, Technicians and Practitioners, as well.
Common criterion for all these fixed prosthodontic materials is their permanent existence in the oral cavity for prolonged time and not to be removed.
The term Biocompatibility refers to the ability of a material to perform its desired function with respect to a medical therapy, without eliciting any undesirable local or systemic effects.
Cytotoxicity is the main component of biocompatibility, generating the most appropriate beneficial cellular or tissue response in that specific situation, and optimizing the clinically relevant performance of that therapy.
Patients are often ignorant of the Serious Consequences of Metal Crowns !
Added, with no proper Dental Insurance, Patients often bargain and ask for economical pricing, which has set a wrong Market. So, Comparative Cheap Metal alloys have creped in to meet the demand, instead of maintaining Quality and educating the Patient.
Do you know Cheap Metal Crowns may cause serious allergic reactions ? 😮👇
Yes! Concerns over allergic reactions to dental restorative and orthodontic materials have increased in the past few years.
Biocompatibility of fixed prosthodontic materials is often overlooked because many practitioners assume that, if the material is on the market, its biocompatibility does not need to be questioned and Patients blindly trust and feel happy too, for low pricing🤦♀️
Lets Discuss- Here I wish share some of my case studies & apprise the reader of the serious Consequences of the callous selection of Dental Crowns !
In most instances intraoral allergies result in a Type IV, delayed contact response
most often affecting those oral sites in direct contact with the allergen that may manifest in various ways including
Lichenoid reactions,
Lichen Planus
Burning mouth/burning lip syndromes,
Cheilitis and lip swelling,
Oral granulomatous reactions,
Gingival hyperplasia,
Non-specific erythema and edema,
Ulceration
Hypersensitivity reactions to dental materials require the release of allergenic antigens from the material. Release of metal ions occurs due to corrosion, the enzymatic activity of saliva, a more acidic oral pH, and other factors. These factors have less effect on non metallic dental restorative materials.
In fact, The oral cavity is less likely to manifest a contact allergic reaction than skin. This may be due to the flushing and buffering effect of saliva, to the increased vascularity of oral mucosa compared to skin and possibly to the lower number of Langerhans cells and T lymphocytes found in mucosa.
It has been estimated that expression of a contact reaction in the oral cavity requires 5-12 times the antigen exposure than required on skin. Now one can imagine, how Toxic the metal should be, to cause Oral Lesions
Hypersensitivity reaction to nickel (Ni) and Chromium (Cr), Ag-Pd, Co-Cr, containing dental alloys has been a matter of special concern . See above 👆 the rusted Metal Crown!
Silver (Ag) is a noble element but the American Dental Association (ADA) has classified it as a base metal because of its relatively high ionic release and reactivity in the oral cavity.
Clinical manifestations - Oral lesion occurred, in this female Patient👇 due to that metal Crown. A Biopsy👇 was taken which turned out to be, as suspected, Lichenoid reaction from one site- dorsal Tongue.
Its due to metal corrosion resulting from oral environmental factors such as warm oral temperatures, salivary enzymatic components, electrochemical (galvanic) currents.
and frank Lichen Planus from Biopsy taken at other site 👇buccal mucosa
Dental alloys are complex metallurgically.
More than 25 elements in the periodic table can be used in dental alloys. The complexity and diversity of these alloys make understanding their biocompatibility difficult, because any element in an alloy may be released and influence the body
One should note here that An alloy is a metallic material formed by the combination of two or more metals and An alloy is not homogenous throughout its structure.
Whether an alloy is single-phase or multiple-phase is dependent on the solubility of the alloy elements. The phase structure of an alloy is critical to its corrosion properties and its biocompatibility.
Two systems are currently responsible for standards that can be used to document products quality: ANSI/ADA and ISO. They do not require specific biologic tests to approve the quality of a new dental material. Rather, they place the responsibility on the manufacturer to present evidence for a compelling case for approval. So, it is up to the manufacturer to defend the substantial equivalence argument.
The evidences used for approval of quality of a dental material consist of in vitro tests (cell-culture), in vivo tests (animal tests), and usage tests (clinical trials of the material). However, it is becoming increasingly impractical to test all new materials through all of these stages.
The problems of time, expense, and ethics have limited the usefulness of this traditional biologic testing scheme. Therefore, companies market materials with little clinical experience, and may rely heavily on in vitro and animal tests.
Biological systems may have harmful or destructive effects on dental materials, classified as biodegradation.
It is important to evaluate the material reactivity in the oral cavity, which is governed by thermo-dynamic principles and electro-chemical reaction kinetics.
This means that when an alloy is placed in the oral cavity, the alloy-saliva system will be driven towards a state of thermo-dynamic equilibrium. At equilibrium, the alloy either will remain stable in its elemental form or oxidize into its ionic form (corrosion)
The release of these corroded elements continues for months or years at low levels and is not visible to the eye.
This is another Case 👆 A biopsy was taken and dysplastic changes were mild enough
Metal compound specific T cells might be responsible for the development of linear lichen planus. (LP)
Nickel–chromium alloys containing high amounts of copper (12.3%) showed the highest cytotoxicity.
In addition to affecting adjacent oral soft tissues, ions released from metallic restoration may also have an adverse effect on nearby alveolar bone. Osteoblastic differentiation of human bone marrow cells was influenced, in vitro, by Fe3+, Cr3+, and Ni2+,
Release of metallic ions from the metalloid-lattice of dental alloys into the oral cavity occurs, and thermo-stable substances such as chlorides, sulfides, and oxides, are formed during this process and cause Lichenoid reactions. (LR)
LASER Treatment was initiated and the crowns were replaced with Zirconia Crowns👇
Zirconia is now used for a variety of reasons such as crowns and bridges, implant abutments, intramucosal inserts, implants and most recently as a scaffold for bone grafting procedures.
Zirconia because of its biocompatibility has gained immense popularity as well as the fact that fewer bacteria adhere to the zirconia surface.
Powders and particles of zirconia on different cell lines do not induce cytotoxicity or inflammation ( Tumor Necrosis Factor, TNF-α quantification).
zirconia report the absence of toxic effects on connective, immunologic, or bone tissues. Increased proliferation of SAOS2 osteoblasts. The Bone Implant Contact is greater in Zirconia as in comparison to Titanium.
Zirconia restorations require lesser amount of tooth reduction thus preserving more tooth structure and improving the resistance form of the tooth.
Zirconia do not cause discoloration of the gingiva most commonly caused by porcelain fused to metal crowns👇 because of the interaction of the metals with chromogenic bacteria in the dental plaque to produce surface stains.
Zirconia possess superior aesthetics by virtue of it being metal free and possessing better light reflection properties. They are indicated for masking of dyschromic abutment teeth as well.
Patients who are atopic and inclined to allergies and those who have previously demonstrated an allergenic reaction to jewelry, tattooing, body piercing, etc., may benefit from Patch testing before initiation of dental treatment in an effort to identify materials likely to induce an adverse reaction. It is also not clear how many different metals are involved in the alloy to test.
Patch testing is considered by many to be the “gold standard” for contact allergy testing although its use continues to be controversial because it may yield false negative or false positive results. For example a weak (macular erythematic) response to a particular metallic salt may represent an irritant effect rather than a true hypersensitivity reaction.
Summary
Ignorance is not always a bliss! Be aware that Metal Crowns may cause serious allergic manifestations especially if you are Immune compromised. I see many patients with such allergic reactions in my daily Practice and I see them feel sorry to spend again to replace them with Biocompatible Medical Grade Crowns! So, Hope this Blog keeps you apprised of the facts.
To Get your Lichenoid reaction/Burning mouth-Burning lip syndromes/Ulceration issues, due to metal Crowns evaluated, Please book your slot at our website dentistlotusclinics.com
Issued in Public Interest
Disclaimer: Lotus Clinics claims no credit for certain images / Videos featured on our blog site taken from web, unless otherwise noted. This is written for Educational purposes and to bring awareness among public, with case Study pics of my Patients with their written /Audio/ Video Consent
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