3D digitization
Here, your dentist uses special cameras to take the images of your teeth and surrounding structures. Your dentist scans inside and outside of your mouth. Then, your dentist creates a three-dimensional image of your teeth in the form of a digital mesh of dots.
CAD
CAD stands for the Computer Aided Designing. Using CAD, your dentist designs your fixed dental prosthesis such as crowns and veneers via computers at his/her office and makes the necessary adjustments to mimic your natural teeth.
CAM
CAM stands for Computer Aided Manufacturing. It carves the crowns and veneers in your dentist’s office. CAM has units which rotate in 3 to 5 axes while carving your crowns/ veneers, to make them look natural.
Procedure for making your dental crowns and veneers using the CAD-CAM technology
After a thorough examination of your mouth, your dentist anesthetizes your teeth for which you need crowns or veneers.
Once the anesthesia starts working, your dentist files your teeth which makes sure your teeth hold your crowns and veneers well.
Next, your dentist takes the impression of your prepared teeth. In the CAD-CAM technology, there are special cameras know as intra-oral cameras. They are smaller than the point of your ball pen and emit a blue light which helps your dentist click the images of your teeth. He/ she transfers the images to the computers at his/ her office and designs a digital mesh of dots out of your teeth.
After that your dentist edits the design for all the fine details of your teeth such as indentations, ridges, and pits to make your crown look like your natural teeth.
Once the final design is ready, a milling machine at your dentist’s office carves a replica of the digital image to make the crown or the veneer.
The CAD CAM technology carves a veneer or crown out of a single block of ceramic; thus, they are known as monolithic. The block is a combination of lithium disilicate and lithium metasilicate. The property of lithium metasilicate helps your dentist carve crowns/ veneers. The carving takes only 15 minutes.
Once your dentist finishes the carving, he/ she lets it crystallize at the temperature of 850-degree Celsius for 20 to 25 minutes. During this procedure lithium disilicate crystallizes whereas lithium metasilicate dissolves. This particular process makes your crowns and veneers stronger and translucent.
At the end of this process, the quantity of crystals in the crown/ veneer, is 70% of volume and the flexural strength of crown/ veneer is 360 to 400 Mpa.
You have several options to make the veneers and crowns look natural. You can either layer the incisal edges with Nano fluorapatite ceramic or coat the incisal edges with stains. However, the layering technique gives you longer lasting results.
Once the crowns/ veneers are ready, your dentist checks the fit in your mouth, makes necessary adjustments if at all needed, and glues them on to your teeth.
Five differences between your CAD-CAM restorations and traditional ones
1. Quick
CAD-CAM restorations are quick. You can get them on the same day of your appointment. On the contrary, traditional ones may need few weeks. CAD-CAM crowns are also known as single day crowns, chair side crowns or CEREC crowns.
2. Comfortable
In CAD-CAM, your dentist uses a comfortable scanner known as a CEREC AC scanner for taking the impression of your teeth. Whereas, traditional ones use a sticky material for taking the impression of your prepared teeth. It is uncomfortable and some of us may feel a vomiting sensation with it.
Your dentist sends the impression to the lab and the technician works out a crown/ veneer out of it. With the CAD-CAM technology, you don’t need that impression.
3. Promise better oral health
CAD-CAM restorations save your natural teeth more than the traditional crowns. Traditional crowns need more trimming to make sure your crowns are well seated. Having more of your natural teeth structure, means better oral health. However great dental restorations are, natural is always the best.
4. No need of a temporary crown
Till the traditional crown is ready, you will need a temporary crown to cover your prepared teeth. With CAD-CAM you don’t need temporary crowns, as you get the CAD-CAM crown on the same day.
5. Economical
CAD-CAM restorations save you money in the long run. You don’t need additional appointments to fix your restorations. There is no waiting period. For many of us, saving time may mean more opportunities to earn.
Downside of CAD-CAM
They are not ideal options for your back teeth. As you tend to chew harder foods with your back teeth, metal crowns stay longer there. Metal ones are stronger and better resistant to fracture/ wear and tear. Metal crowns can also be a combination of various alloys, which enhance their bonding with tooth as well as increase their resistance.
If your tooth has fractured below the gum line, traditional crowns may fit you better as intra oral cameras may not capture perfectly below your gum line. You might also need crown lengthening in this case.
How do you make sure your CAD-CAM restorations last longer?
If you maintain them well, your CAD-CAM restorations last for a minimum of ten years and much longer.
- Practice regular oral hygiene habits such as brushing thoroughly with a good quality paste and brush, brushing twice a day, and flossing every day.
- Meet your dentist every six months or whenever you face an oral health problem.
- Avoid biting inedible things, especially with your front teeth.
- Avoid over exposure to coffee, tea, and wine as they can stain your restorations.
- If you are in sports, remember to wear mouth guards.