Arcus Laboratory

ARCUS LABORATORY is one of the premier dental laboratories in the US. It was founded in 1990 by Steven McGowan and is located on the north shore of Lake Washington, in Seattle. We are committed to evidence-based excellence with the materials and techniques we use to create your restorations. We attend and hold courses throughout the United States and internationally as well, keeping us on the cutting edge of material choice and technology. Our opinion is often sought by dental professionals and manufacturers to evaluate materials and techniques relating to dental technology.

Monthly Archives: December 2014

Personality of Teeth: A Visual Encyclopedia

Several years ago I was given thousands of extracted teeth. These teeth were collected during volunteer work at clinics in the southeast of the US. This collection of teeth changed hands several times before they were given to me. It has been very helpful for me to study and photograph these teeth and I have always wondered if I could find a way to share this collection with others. A diverse collection of teeth is a treasure filled with useful information. About a year ago I decided to document these teeth with photography. The result is Personality of Teeth: A Visual Encyclopedia.

This electronic book has taken over a year to complete. For each type of tooth (maxillary central incisor, for example) there were hundreds of samples to choose from. Each tooth is photographed from five perspectives. In total, there are over 2,000 views of more than 500 teeth. I spent several weeks photographing these teeth from different views using various light sources. I finally settled on a technique that would best convey the form, color, and texture of these teeth. There are also study pages that describe landmarks and a glossary of terms.

The analyzing, sorting, cleaning and photographing of these teeth took hundreds of hours. I have learned so much from viewing these teeth through my macro lens, and blown up on my computer screen. I believe this project has elevated my work and has given me a new appreciation of the diversity of nature.

The Personality of Front Teeth

One of the most basic and valuable subjects necessary for dental professionals is dental anatomy. A fundamental component of dental anatomy is tooth morphology. There are many well known dental anatomy textbooks that tackle the complex topic of tooth form. In many cases these textbooks use artist’s renderings of teeth. They assign average measurements in an attempt to create a standard tooth shape for each tooth in the mouth. Artist or computer renderings of tooth shapes give basic information but don’t fully convey the rich diversity of sizes, shapes, colors, and textures. In order to quantify this diversity I have sorted, cleaned, photographed, and measured 600 extracted maxillary incisors; 200 centrals, laterals, and cuspids. I have compiled my data in an article that has been submitted for publication. If and when this gets accepted, I will post the full article.

Central

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Slow cooling protocol improves fatigue life of zirconia restorations

One of the newer restorative materials used today in dentistry is zirconia. Zirconia has been used as a biomaterial for over 25 years. What Future for Zirconia as a Biomaterial? Although much has been written about zirconia, there is surprisingly little clinical research in the field of dentistry. The lack of research has created some challenges with understanding this material.

As mentioned, zirconia has a long history of use in the medical field but is relatively new to dentistry. Why has zirconia become popular in dentistry? There are some driving factors behind the increased popularity of zirconia.

In dentistry the standard of care for dental restorations has been gold and gold alloys. Gold alloys can have porcelain veneered to the outside to make tooth colored restorations. Gold prices have skyrocketed recently which has caused dentists to seek out less expensive alternatives.

The use of CAD/CAM technology has increased within dentistry. Dentists and labs are increasingly turning to this technology to replace tasks that were traditionally done by hand. Zirconia can be milled (CAM=computer aided milling) easier than other restorative materials. Zirconia milled for industrial applications has been used since the late 1970’s, with widespread use since the 1990’s. The mills used today for dental applications were originally developed for industrial uses. These industrial machines and methods have been adapted to suit the dental profession. Millions of zirconia dental restorations have been fabricated worldwide using machines and methods based on industrial technology and experience.

This excellent article addresses some of the common problems with zirconia restorations. Understanding the problems associated with zirconia allows me to use this material more comfortably in the proper situation. This can be said for all the restorative materials I use.

I cautiously use zirconia restorations. Like all of the restorations I make, I want to be aware of current research so I can be comfortable using newer materials. I never want to use a material solely because it is popular. I want to make sure my choice is evidence based.

Slow cooling protocol improves fatigue life of zirconia restorations. [pdf]