Material Safety for Nightguards

Material safety is an important concern for all consumer products. More so for one that you wear overnight. Metatooth’s custom night guard is made from material cleared by the FDA for use in medical devices. What’s your night guard made of?

material safety data sheet

Methyl Methacrylate (MMA)

MMA is irritating to the skin, eyes, and mucus membranes. The FDA has taken action to remove the use of MMA in nail care products.

Methyl methacrylate is used safely in many consumer products, in accordance with the EPA.

Exposure to methyl methacrylate is primarily occupational, through dermal and inhalation routes. Potentialfor exposure exists for employees of manufacturers of methyl methacrylate and its polymers, as well as doctors, nurses, dentists, and dental technicians.

The Methacrylate Producers Association, Inc provides information on this material. The majority of MMA is converted to polymers before being used in consumer products. Exposure to MMA from these products is unlikely.

If you have a sensitivity to MMA, then our custom night guard may not work for you.


The Centers for Disease Control and Prevention (CDC) maintains a fact sheet on phthalates. The CDC has this to say about how people are exposed.

People are exposed to phthalates by eating and drinking foods that have been in contact with containers and products containing phthalates. To a lesser extent exposure can occur from breathing in air that contains phthalate vapors or dust contaminated with phthalate particles. Young children may have a greater risk of being exposed to phthalate particles in dust than adults because of their hand-to-mouth behaviors. Once phthalates enter a person’s body, they are converted into breakdown products (metabolites) that pass out quickly in urine.

The CDC provides a list of items containing phthalates.

  • vinyl flooring
  • adhesives
  • detergents
  • lubricating oils
  • automotive plastics
  • raincoats
  • soaps
  • shampoos
  • hair sprays
  • nail polishes
  • polyvinyl chloride plastics (plastic packaging film and sheets, garden hoses, inflatable toys, blood-storage containers, medical tubing, some children’s toys)

The health effects of low levels of exposure are unknown. More research is needed!

Our custom night guard does not contain phthalates.


Our custom night guard does not contain BPA.


Our custom night guard does not contain latex.

Additional material safety information is available from Metatooth on request. What are your material safety concerns? Post them in the comments!


Methyl methacrylate. Wikipedia., n.p., Accessed 28 February 2020.

Nail Care Products. FDA., 6 Mar 2018, Accessed 28 February 2020.

Methyl Methacrylate. EPA., n.p., Accessed 28 February 2020.

Global Product Safety Summary: Methyl Methacrylate. Methacrylate Producers Association, Inc.,  27 Nov 2019, Accessed 28 February 2020.

Phthalates Factsheet. CDC., 7 Apr 2017, Accessed 28 February 2020.

custom-night-guard mouthhealth

Teeth Grinding (Bruxism)

Teeth grinding effects 1  in 10 adults. It is even more prevalent in children, but declines with age. Bruxism (BRUK-siz-um) is the condition of grinding, gnashing, or clenching of your teeth. Sleep bruxism — night-time grinding — is most common, although awake bruxism does occur. Symptoms include jaw, ear, and head-aches. Teeth can also be damaged. Ask your dentist if you have signs of bruxism.

Stress and Anxiety

The causes of bruxism are not completely known. They may be physical, psychological or genetic. Stress and anxiety may induce awake bruxism. Sleep bruxism may be activity related to sleep arousals (awakenings from sleep apnea or snoring).

Reduce stress at bed-time by:

  1. try to relax in the hours before bedtime
  2. maintain a consistent soothing routine
  3. create a cool, comfortable, and dark sleep environment
  4. keep work-related items like computers out of the bedroom

Alcohol, Nicotine, and Caffeine

All of these drugs can interfere with normal sleep patterns which could result in an increase of bruxism. Other conditions like sleep apnea and snoring are also aggravated by these substances. Consider lifestyle changes that reduce or eliminate alcohol, nicotone, and caffeine for improvements in sleep patterns.

Sleep Apnea

Sleep apnea and snoring are thought to contribute to sleep bruxism. Seek treatment for sleep apnea from your doctor or dentist. Night guard users have reported both increases and decreases in the incidents of snoring. More study is needed to better understand how devices like occlusal splints impact these medical conditions.

Occlusal Splint (Night Guard)

An occlusal splint is commonly used as a night guard for teeth protection. Splints do not stop the grinding, but they do protect the wearer’s teeth from damage. Splints can be purchased over-the-counter or through a dentist. Over-the-counter night guards are made by thermoforming or “boil and bite”. Many dentists offer a custom-made occlusal splint. This type is now available direct to the consumer.

occlusal splint

Do you have experience with a night guard? Tell us about it in the comments!


Blake, K. (2016, February 29). Teeth grinding: Causes, Symptoms and Diagnosis.

Mayo Clinic Staff. (2014, July 22). Bruxism (teeth grinding).

National Sleep Foundation. (n.d.). 3 Tips for Coping with Bruxism or Teeth Grinding.


3d-printing dentistry marketresearch product

Yankee Dental 2020

Metatooth went to Yankee Dental 2020 and here’s what we found.

3D Printing

Micron Dental was showing their P305 printer. This printer uses LCD technology as the light source. Micron claims less lens distortion issues with this technology over the SLA and DLP types. It is being sold as a bundle only, which includes a wash & cure station.

The P305 lacks the design flair of the Formlabs Form 3B  or SprintRay Pro. The exterior design would not effect performance, but it does limit access to the print plate, with a side door of just 18 inches. Compare this to the “hatch” approach provided by the other two vendors. Does this effect usability? Micron users please comment below!

Formlabs was present as well, showing the Form 3B. No new materials were shown. The hunt is still on for a printable clear aligner tray. Everyone seems happy to be selling model resin! Formlab’s PreForm software is free to download and use, which was news to Metatooth.

Finally, Great Lakes Dental Technologies showed an economy desktop LCD printer the UNIZ Slash Plus.

Dental CAD

Metatooth watched a demonstration of 3Shape‘s Bite Splint and Indirect Bonding modules. 3Shape’s design software is available stand-alone, at prices comparable to other stand-alone software. However, the yearly maintenance fees are required for the software to operate.

Look for 3Shape to support Polygon File Format (*.ply) in the near future. This will enable non-3Shape users of this data to receive the color information collected by TRIOS scanners. This would be a welcome addition to those supporting open standards and protocols in the dental industry.

Practice Management Software

There were a number of companies offering software products that worked with the leaders in practice management software. Hopefully more of these offerings will keep coming. Metatooth recommends software products that integrate using the vendor’s API, not via an understanding of the vendor’s database schema.

This market is quite regional, so for the Northeast, Metatooth considers these the market leaders.

  1. EagleSoft from Patterson Dental
  2. Dentrix from Henry Schein
  3. OpenDental

Relative newcomer carestack might be one to watch.


Artificial Intelligence vendors were centered around perio-charting assistance and some other voice-to-text tasks. BOLA.AI offered the most functionality. This area will continue to grow, especially as practice management systems (see above) move to the cloud and add API support.


Direct-to-consumer companies looking to add a clinical channel were present. quip was the most well known to Metatooth, but another toothbrush service — BURST — was also on the scene. Colgate, Oral-B, and the like had throngs at their booths. When does quip or BURST become an acquisition target?

There was also an anti-snoring device from Zyppah. This self-molding thermoform device is available directly from the company. A “dentist only” channel was being presented.

Metatooth had a great time at the vendor exhibition of Yankee Dental 2020. What did Metatooth miss? Tell us about it in the comments!

Yankee Dental 2020



friday links

Friday Links

Friday links to a collection of news items I’ve recently come across. Each is not enough for a full blog post, but maybe I can cobble one together! My own news at the bottom.

Here is another example of a 3d-printed implant this time for plastic surgery. It’s a 3d-printed breast implant which will start clinical trials in Germany by the end of year. It’s a resorbable structure that allows for the recipient’s own tissue to be used as the bio-mass, instead of silicon or polyurethane.

What’s the latest on SmileDirectClub? While anticipation of the initial public offering was high, it ended up being a big dud. The stock dropped again after their first earnings report. Note that the past quarter’s revenue was above expectations: $180MM vs $165MM. That seems like plenty of money!?  It’s definitely not if you spend $600MM. They remain on track to increase revenue 78% this year. SmileDirectClub (NASDAQ: SDC) has stumbled, but with the HP partnership and continuing consumer demand, it doesn’t seem like they are going away anytime soon.

Formlabs recently announced the Form 3B and are all in on dental with their dedicated business unit. The white case of the 3B is a nod to the desired clinical setting for these devices. This market needs advanced materials and Formlabs appears to be investing in their development, along with the creation of a support organization to differentiate themselves from other OEMs at this price point.

What’s the latest from Metatooth? The first printed night guards have been received!

Alien Milling is my manufacturing partner. There are still things for me to learn about digital workflows! Each participant has embraced digital platforms, but they don’t work together. A challenge and an opportunity.

Thanks for reading Friday links. What have you noticed in the news regarding dental, 3d-printing, and digital workflows? Tell me about it in the comments!



EforAll Lynn Winter 2020 Cohort

The EforAll Lynn Winter 2020 Cohort is coming together and Metatooth will be part of it! EforAll’s Lynn Community offers twice-a-year business accelerator programs and “pitch contests” focused on nurturing local entrepreneurs. Core values are Inclusivity, Empathy, Collaboration, Respect, Performance, and Drive. Entrepreneurship for All began in Lowell-Lawrence, MA as Merrimack Valley Sandbox in 2010.  It is the brainchild of Jaishree and Desh Deshpande, with initial funding through their Deshpande Foundation.  It has since expanded across communities in Massachusetts and has recently welcomed Longmont, CO to the fold.

It’s already been helpful to participate in the application and interview process. Interviewers and application reviewers have highlighted questions and prompted reflection on my motivation and goals. The core of the program is twice-a-week workshops over the next 12 weeks. Mentor matching happens at program start and mentors meet with entrepreneurs over the course of the following year. Participants are expected to leave the 12 week workshop period with a 9-month plan to grow their business.

There is a lot of moving parts in any operation. I’ve previously relied on SCORE and the Greater Lynn Chamber of Commerce for business questions and advice. I plan to go back to that well, too!

Thanks to the staff & volunteers of EforAll Lynn for their attention during the application process. How are you engaging with your local community to strengthen your business and achieve your goals? Tell me about it in the comments!

custom-night-guard development

Night Guard Design

Night guard design is done! Read about my scanning experience here.

I am using FullContour, LLC for design services. Super easy interfaces, works well with STL files. I use “design approval” but I am not sure I would make any changes. 2mm occlusal, 1mm buccal/lingual. Shallow trim. Can’t wait to evaluate the fit!

What’s your night guard design preference? Tell me about it in the comments!

dental-lab review


SHINING 3D’s AutoScan-DS-EX is an entry-level desktop dental scanner.  Their website describes it as cost-effective and at $5,000 it is. For that price, you get structured white light, two cameras, a swing arm & turntable, a collection of mounting jigs, calibration plate (more on that later), a USB drive with software, a USB dongle for licensing, and a package of Blu Tack.  You will need an Intel Core i7 processor, NVIDIA GTX 750 graphics card, and Windows 7 or later. Check out Metatooth’s setup!

I had two problems setting up. Each were quickly addressed by my supplier, Bayshore Dental Studio, and SHINING 3D Dental Support.

1. The software version on the thumb drive was not able to connect with the scanner.  I was sent a Google Drive link to download version 2931. It would have been nice to get this information ahead of setup, but it was quickly resolved. The customer service rep used Team Viewer to review my machine, this happened over night for me, given their location.

2. Take off the protective plastic cover before trying to scan the calibration plate!

The case entry form will be familiar to exocad users. I haven’t had reason to scan more than impressions. Additional scans were needed to fill holes; the default scan paths did not give complete coverage. Hopeful for a way to change the scan paths or possibly issue arm/turntable and capture commands to the scan server itself.

Any other AutoScan-DS-EX users out there? What has your experience been? Tell me about it in the comments!


NGINX Heroku WordPress

NGINX, Heroku, and WordPress combined. This website is powered by WordPress on Heroku. Details on configuration are here.

My next #DevOps task is to add NGINX in front of the WordPress application. In the future, this could be used as a load balancer. Until then, NGINX will reverse proxy the requests to the Heroku application instance.

To start, I spun up a virtual machine running Ubuntu on Amazon’s EC2. Check out how to install and configure NGINX here. Make sure to open your firewall to HTTP & HTTPS traffic!

I encountered two major issues:

  1. The request passed by NGINX through the reverse proxy was not being understood by Heroku’s application stack.
  2. Once the application stack properly handled the request, WordPress’s response triggered a redirect loop.

Reverse Proxy

Heroku’s stack uses the host of the request to route to the appropriate application instance. The originating Host value is (in my example) ‘’. Heroku shouldn’t respond to this. Turn off the app’s Custom Domain feature if it does. Update the reverse proxy to set a new Host header that Heroku will respond to.

server {

    location / {
        proxy_set_header Host;

    # configure SSL here

Redirect Loop

Setting the Host request header got Heroku’s attention, now WordPress responds to that request with a redirect loop. I encountered this problem while trying to configure an HTTPS-only WordPress installation. The way out of the redirect loop was to update two more request headers and then to use those headers in the WordPress configuration. Here’s the new section of wp-config.php

if ( $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https' )
        $_SERVER['HTTPS']       = 'on';
        $_SERVER['SERVER_PORT'] = '443';
        define('FORCE_SSL_ADMIN', true);

if ( isset($_SERVER['HTTP_X_FORWARDED_HOST']) ) {

That gets WordPress to not redirect to https on these proxied requests, but only if the request headers of X-Forwarded-Proto and X-Forwarded-Host are specified. The NGINX configuration now is:

server {

    location / {
        proxy_set_header Host;
        proxy_set_header X-Forwarded-Host $host;    
        proxy_set_header X-Forwarded-Proto $scheme;

    # configure SSL here

That’s how I got NGINX, Heroku, and WordPress to play well together. Next task is to use an upstream for the proxy_pass directives. What’s your infrastructure layout and what did you learn along the way? Tell me about it in the comments!


Docker Ubuntu 19.04

Docker on Ubuntu 19.04 is a cinch. “Dockerizing” an application is a great way to ensure you understand it’s dependencies. I always forget this last bit when setting up a new machine.

sudo usermod -aG docker username

Otherwise, I recommend this Medium post by Grigor Khachatryan.

It turns out that LAMP Ubuntu 19.04 is the most popular Metatooth blog post. Can’t argue with success. More #DevOps posts forthcoming! I’ll certainly keep posting about teeth and technology, too.

What other “crowdsourced” finding has surprised you recently? Tell me about it in the comments!



SmileDirectClub IPO

SmileDirectClub and it’s initial public offering is in the news. The numbers cited are astounding: revenue of $423.2 million in 2018; 700,000 customers since 2014; $945 million addressable market; $393 million in funding (Shen, 2019).

Legal and regulatory hurdles remain. SmileDirectClub is suing the state dental boards of Alabama and Georgia to remove the requirement that a licensed dentist be present for the 3D scan of the patient. Arkansas has a law, co-written by a state representative who is also a dentist, that requires in-person exams before a doctor can treat a patient remotely.  If the attorney general of that state takes action, expect a lobbying effort by SmileDirectClub (Mandelbaum, 2019).

The question remains: can you collect enough data to make a treatment decision (for example, start clear aligners or referral to a local orthodontist) remotely? If it’s really not possible, then more innovation is needed to make it so. Teledentistry provides a way to bring better oral health to under-served regions. The technology and infrastructure built to disrupt the orthodontic industry should have a side benefit.

Align Technology Inc.’s 17% stake is looking pretty good. What other disruptive startups have backing by industry leaders? Tell me about it in the comments!


Shen, Lucinda. Fortune (August, 16, 2019) Brace Yourself: SmileDirectClub Is the Latest Unicorn to File for an IPO Accessed August 23, 2019.

Mandelbaum, Robb. Bloomberg Businessweek (August, 22, 2019)  A Tooth-Straightening Startup Runs Into Resistance Accessed August 23, 2019.