I often hear that people with metal allergies are more likely to have mouth ulcers due to dental metal.
Recently, I was interested in titanium used for implants and dental metals, and had the opportunity to investigate in detail, ask a dentist, and show me a catalog, so I would like to summarize the metal allergies of dental metals. think.
There are three main metal parts used for dental treatment
- Dental metal for coverings and fillings
- Implant
- Orthodontic brackets and wires
For each, I would like to summarize in detail the types of metals used.
Metal allergies to dental metals can spread systemically
Metal allergies can be broadly classified into two types.
・Local metal allergies
・Systemic metal allergy
Local metal allergies are those in which the symptoms of metal allergies appear only in the areas where the metal touches.
I think most of the metal allergies caused by jewelry are local metal allergies. In addition, mouth ulcers around dental metal are also local metal allergies.
On the other hand, what you should be careful about in dental metal is systemic metal allergy.
This is because saliva in the mouth dissolves the metal parts used for dental treatment, and metal ions are absorbed from the digestive organs such as the stomach and intestines. Because it can spread.
No way, the metal parts used for dental treatment have melted out!
You may think that human body fluids have a very strong ability to corrode metals, and metal ions are always dissolved from dental metals. For example, if you touch the metal of the cover with your tongue, you may feel the taste peculiar to metal, but this is the melted metal ion.
In addition to eczema and itching, metal allergies caused by dental metals may be the cause of continued poor physical condition such as fatigue, headache, stiff shoulders, and fatigue.
Gold-silver-palladium alloy used for tooth coverings and fillings
Among dental metals, the so-called “silver teeth” are the cause of metal allergy problems.
This silver tooth, whose name is silver tooth, is actually an alloy of gold, silver, copper and palladium. I often hear dentists call them kinpara or ginpara.
The composition is 12% for gold (Au), 52% for silver (Ag), 15% for copper (Cu), and 20% for palladium (Pd).
Among these components, palladium and copper are particularly prone to cause metal allergies.
If you are allergic to metal, it is recommended that you remove these silver teeth and replace them with ceramic or resin.
By the way, in Japan, the spread of silver teeth is remarkable because these silver teeth are covered by insurance, but it seems that they are often treated with resin overseas.
Titanium alloy is used for implants
The number of reports of metal allergies other than “silver teeth” mentioned above is extremely small compared to silver teeth, but I would like to write about it.
Titanium alloys are often used for dental implants.
Implant refers to implanting medical equipment in the human body. For dentistry only, it refers to artificial tooth roots. Bolt-shaped titanium is embedded in the bone, and artificial teeth are fixed on it.
I interviewed a dentist about the alloy composition of this titanium implant, but I heard that the manufacturer does not want to reveal what kind of titanium alloy it is.
In addition, there are more than a dozen implant manufacturers, all of which have different standards for screw pitches and tools. Perhaps it’s because each manufacturer surrounds the dentist. (I hope that someday there will be a movement of unified standards like the world of industrial screws in this world as well.)
Even if you say titanium implants in a nutshell, it may not be possible to track what alloy composition of which manufacturer. Therefore, the content of the alloy composition of the titanium implant described below is just a guess based on the papers and the alloy composition.
Alloy composition of titanium implant
Upon examination, it seems that a titanium alloy with a composition of Ti-6% Al-4% V, so-called Rokuyon Titanium, is used (was used?) For implants. It is α + β titanium, which is a mixture of α-phase titanium and β-phase titanium, and is a harder and stronger alloy than pure titanium.
But is this still really used? I was a little wondering. Both vanadium and aluminum have lower corrosion resistance than titanium, and I think they will dissolve in saliva. I am also concerned about the toxicity of vanadium. I’ve heard that titanium implants have been reported to have metal allergies for some time, but the cause may be due to these alloying elements.
Besides, it seems that there are many implants that use two types of pure titanium. The softness of pure titanium seems to be supplemented by surface treatment. You can find ones that are coated with hydroxyapatite on the surface to improve the hardness and bondability with bone, and those that are surface-treated by forming a thick oxide film of titanium.
In addition, Ti-6% Al-7% Nb, a titanium-aluminum-niobium alloy, seems to be used. By using niobium instead of vanadium, it is α + β titanium that is more safe.
Perhaps the field of titanium alloys for implants will continue to advance.
By the way, for those who are currently allergic to titanium implants, there are also zirconia ceramic implants.
Also pay attention to the shape memory alloy wire for orthodontics!
Metallic materials are also used for orthodontics.
Orthodontics are made up of two parts: a “bracket” that adheres to the tooth and a “wire” that applies force through the bracket.
It seems that metal brackets are often made of stainless steel. It looks like nickel-free stainless steel, so is it 400 series stainless steel?
When considering metal allergies, it seems that brackets are made of resin or ceramic.
In addition, titanium-nickel alloy, which is a shape memory alloy, is generally used for the wire. However, since this alloy contains nickel, you need to be careful about metal allergies.
As nickel-free wires, β-titanium wires with a molybdenum-zirconium-tin-titanium composition and wires with an alloy called “rubber metal” with a tantalum-niobium-zirconium-titanium composition have also been developed.
If you are allergic to metal and wish to have orthodontics, you should search for “nickel-free orthodontics” to find a dentist who is considerate of metal allergies.
