Selecting a milling center partner might seem a relatively simple task, and for the most part it is. Just try them and see if you like them. However, if you take the time to ask a few basic questions, you can have confidence in knowing that you are providing your dentists with premium quality milled restorations. Asking the right questions can also prevent you from selecting the wrong milling center and avoid potential problems that may results from a poor selection. Below is a list of questions that I think every lab owner should ask when interviewing a potential milling center partner. For the most part, I listed them in the order of critical importance and/or priority in which you should weigh your decision.
1) What Brand of zirconia do you use?
This is a great early question because it leads to discovering the source of the zirconia you use.
2) In what country is the zirconia puck manufactured?
This is important because different countries have different standards for purity and radioactivity levels. (Yes, all zirconia has some levels and various types of radioactivity; some stable and some less stable) The manufacturing standards established in the USA, Europe, & Japan are far stricter than the manufacturing standards in China.
3) What is the Mpa strength and translucency level of the zirconia being used?
An Mpa value of 1,000 gives you the greatest flexibility for indicated use, allowing you to restore singles and round house bridges. As the Mpa increases, the zirconia gains opacity. Although there is no standard measurement currently being used amongst manufacturers to measure the opacity or the lumens, a 1,000 Mpa zirconia should provide you with an acceptable level of esthetics. You should be seeking translucency of about 34%. As the Mpa’s go down, the zirconia becomes more life-like but may not be strong enough for long span bridges.
4) What is your sintering process and or sintering times?
Many milling centers are persuaded to improve the turnaround time at the cost of a thorough sintering process. An effective sintering process requires a very slow ramp up in temperature and a very thorough heat soak at peak temperature. This process can take anywhere from 11-17 hours depending on whether you are sintering single units or bridges. Reducing these sintering cycles can give the appearance of offering a faster turn-around and therefore better service but cheating on the sintering cycle can lead to a weaker zirconia crown or zirconia that lacks vitality.
5) Does the milling center also provide services to dentists or just to dental labs?
I am always surprised to hear that labs have chosen to utilize a milling center that sells direct to dentists. You have to ask yourself if you are willing to financially support a milling center that is actually your competition. Any milling center that works with both labs and dentists obviously has an active marketing campaign to attract new dentist clients. You may be providing the milling center with additional marketing dollars to call on your dentists.
6) What type of mill is being used?
This is important to know because the type of mill greatly influences the level of consistency that you can expect. There are two basic types of mills. Smaller desktop mills designed for the lower volumes of your average small to mid-sized lab, and also industrial mills that are designed for large production milling centers. Some milling centers have purchased mills designed for lower volumes but burden them with the higher volumes found in a milling center. This is like using a small pickup truck to tow a large boat, these mills will not hold calibration due to the excess burden and you may see inconsistencies in the fits of your crowns.
7) What is the turnaround time?
While location seems to be a key criteria for many labs, if the milling center is delivering in a timely manner, then quality and service should weigh heavier than location. However, it is important to know the turnaround time so that you can continue to meet the service requirements of your dentists. A proficient milling center should also offer the possibility for rush services when the need arises, but should should never take more than 4 business days from the time they receive your case to the time it is delivered back to your lab.
8) What is the cut off time for sending files during the day?
For those labs who send design files to the milling center, this is important to know so that you can manage your own schedule and ensure that you meet the service requirements of your dentists. Again, be sure to check on the milling center’s ability to respond to rush orders (without compromising quality and proper sintering as discussed above).
9) Is there a warranty with the product?
You need to know if the milling company will support you in the event of a crown or bridge failure at a later date. We know you likely won’t be charging the dentist for the remake, so the last thing you need is for the mill center to charge you for the crown or bridge that broke in the mouth.
10) What is the price per unit?
This is obviously important so that you can continue to be competitive in your pricing and still generate a profit.
11) What is the shipping policy concerning cost and days in travel?
You will need this information in order to evaluate the actual total cost for your restoratives to measure profitability, and again in order to ensure you can meet the service requirements of your dentists.
12) What is your remake policy?
Similar to the warranty question, it is important to know the remake policy in the event of a failure at time of placement.
13) Who does the design work, computer technicians or dental technicians?
For those labs who are sending models to the mill center you will want to know if a qualified technician is designing your cases or simply a person who is handy with a computer.
14) When I am ready to get my own scanner or my own mill can you help me with the transition?
A good milling center won’t try to keep you down. They will understand that we are an industry that is “in flux” and most milling center customers will eventually purchase their own scanners and their own mills. A milling center should be ready, willing and able to help you in this transition.
15) What level of technical support can I hope to have from the mill center?
A good milling center should be able to provide you with high quality technical support on two fronts. The first front being dental technology support, and the second front being computer technology support as the two technologies have really merged into one.
Keith Crittenden has served the Dental Industry for more than 25 years as a partner in a dental practice and then as a dental lab owner. He is the Founder and CEO of AmericaSmiles Network, a marketing and technology services organization committed to strengthening the dental lab industry by offering services, training and technology. The AmericaSmiles.com patient referral program includes a network of more than 800 local search sites to help people find a dentist. AmericaSmiles Network is a sponsor and partner of the American Cosmetic Dental Lab Association (ACDLA) and provides membership in the ACDLA to all AmericaSmiles Network labs. Keith can be reached at Keith@americasmiles.com or via phone at 708-367-1207.