What is digital dentistry?

An intraoral scanner records the shape of the teeth as a 3D file by taking a rapid series of images. For most patients it is more comfortable than a tray of impression material, and it can be checked and repeated in sections rather than started again from the beginning. The file can be sent to a laboratory immediately, stored, and compared against a later scan to measure whether wear or recession has progressed.

Cone beam computed tomography produces a 3D reconstruction of the jaws at a much lower dose than a medical CT, though still a higher dose than a conventional dental radiograph, which is why it is taken when there is a specific question to answer rather than routinely. For implants it answers what a flat X-ray cannot: how much bone there is across the width of the ridge, where the nerve canal runs, and how close the sinus sits.

Combining that scan with a surface scan of the teeth allows the implant position to be planned against the finished tooth rather than the other way round, and a surgical guide can be produced from the plan.

Restorations are designed on screen, where contours, contacts and the bite can be assessed and adjusted before anything is manufactured. From the design file a restoration can be milled from a ceramic block or printed, depending on the material and what the case requires. The same design can produce temporary restorations that preview the final result, which is particularly useful in larger cases where the patient benefits from seeing and wearing the proposal first.

Milling starts from a solid disc or block of ceramic. The design file drives a cutting tool that shapes the restoration out of that blank in one piece, which is why a milled crown has no join and no layered veneer to chip away from a substructure. Printing works the opposite way, building a model or an appliance up in thin layers of resin on a support structure that is removed afterwards.

Three dimensional printing is the other half of the manufacturing step. Models, surgical guides, trial restorations and appliances are built up in layers of resin from the same design files, on a support structure that holds the piece while it is being built. Once printing finishes the supports are cut away and the piece is washed and cured before it is used.

Printing a model in the building rather than posting an impression to a laboratory removes days from a case and removes a transport step where accuracy can be lost. It also makes it inexpensive to print a proposal, look at it, change it and print it again, which is the part that matters in a large reconstruction.

A scanner does not diagnose, and a milling unit does not decide what should be made. Digital tools shorten steps, remove some sources of error and make planning visible, but the quality of the outcome still rests on the examination, the treatment plan and the execution. Technology used because it is available rather than because the case needs it adds cost without adding value, and it is reasonable to ask why a particular step is being taken.