While diabetes, lupus, and other immune disorders have many known symptoms, like fatigue and headaches, other symptoms of autoimmune disorders are often less visible or well-known to those unaffected by the condition. It’s easy to understand that an autoimmune disease causes a person’s immune system to attack their own body, but there is often an underlying assumption that the target of this attack is a major organ, like the liver, or the thyroid, which can cause visible, full body symptoms if malfunctioning. However, even smaller and seemingly less important areas of the body can fall victim to a misdirected immune system.

In this post, I’ll be focusing on the salivary glands—as it turns out, many autoimmune conditions have the potential to target them, from diabetes to arthritis to Sjogren’s syndrome. This may sound more like an annoyance than a life altering issue, but you’d be surprised: if salivary glands are under-functioning, you can experience difficulty speaking and swallowing and even a changed sense of taste. What’s more, prolonged dry mouth can lead to sores, infections, and tooth decay, as saliva is helps to protect your teeth from bacteria. If untreated, these symptoms can contribute to nutrition problems due to difficulty eating.

Visible effects of dry mouth

Existing treatments for cavities and tooth decay often involve fillings and implants made up of resins, porcelain, or metals (amalgam), which carry their own advantages and disadvantages.

A visual depiction of different materials used as fillings for damaged teeth.

Ceramics, or porcelains, are generally the most natural looking implant choice and is quite durable and strong, but have some detriments due to the way they are placed. These implants must be cemented into the defect of the tooth, and thus are not usable for less-accessible cavities near the gumline or sides of the teeth, and can sometimes require a portion of healthy tooth be removed to place the implant. These implants can still experience chipping and breakage as well, though this is not common. These are generally the most similar to the natural mechanical properties of teeth.

Resins for example have a benefit of being able to closely match appearance of the teeth, and to spare the remaining dental structures as they can be directly bonded onto the tooth. They are also versatile, as they can be used for chips and wear in addition to cavities, and come with less risk of corrosion. However, resins are more prone to shrinkage, which can then lead to additional secondary cavities as debris and bacteria are trapped under and around the ill-fitting filling. Resins are also less durable, and can be broken or worn out, requiring restorations or replacement.

Metals are highly durable, tolerant of moisture during placement, and are better at avoiding problems with ill-fitting seals.  These are one of the best options when considering long term strength and durability, but aesthetically are the worst option, as they cannot be readily blended in with surrounding teeth and often darken over time. In spite of their great functional properties many countries’ dental associations have supported scaling down their usage of metal implants because they often contain mercury, and while the exposure levels very low, there is still a risk of toxicity. Additionally, there is some concern for long-term success of these implants because of the difference in their mechanical properties when compared to the surrounding natural tooth, which can cause stress shielding and fatigue failures.

While BMGs don’t provide much improvement in the aesthetic side of implants, they have great promise for providing a strong, durable, non-corrosive implant suitable for the often-harsh and wear-inducing environment of the mouth. BMGs, lacking long-range order, have high yield strength, low Young’s modulus, high resistance to corrosion and fatigue, and good formability. In short, with the exception of appearance, they are able to combine all of the benefits of existing dental implant materials with none of the disadvantages.

BMGs have a lower young’s modulus than pure metallic implants, but retain great compressive strength, as shown by these images of BMG surfaces after application of a compressive load.

Another benefit of BMGs for use in dental implants is their ability to osseointegrate into the surrounding material, which can provide support to the surrounding tooth without creating the same stress-shielding problems present in metal implants. BMG alloys can also be made with no or very low presence of toxic materials, giving them an edge over metal implants that frequently make use of mercury. Another benefit:  extremely minimal corrosion rate and lack of change in the surface morphology of samples when they were immersed in a PBS mixture meant to simulate a body environment. This means that there is unlikely to be leaching of metal ions into the surrounding tissue and solution, and lower incidence of particle disease that is found in other replacements.  

Corrosion resistance doesn’t just help to avoid toxicity problems, but also mechanical issues. In metals, it can lead to integrity failure, which can lead to additional surgeries or procedures to fix or replace the implant. This comes at added financial cost but also potentially at the cost of existing tooth; metal implants are more likely to require drilling out when they are removed, which significantly affects the surrounding tissue.

An added bonus of BMGs: antimicrobial performance. Because of the silver-containing composition and the corrosion-resistance of BMGs, the material helps to ward off bacteria and fungi, which were mentioned above as main concerns for dry mouth patients. The alloy is capable of inhibiting plaque accumulation, which is of great importance when saliva is not present to aid in this process.

Jaws may not have had the prettiest smile, but look at functionality!

sources:

https://www.sciencedirect.com/science/article/pii/S0925838814016004

https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201505347