Focus On: Minimally Invasive Dentistry

Jose-Luis Ruiz, DDS

Jose-Luis Ruiz, DDS, shares his opinion on CAD/CAM technology, and how much it currently contributes to minimally invasive dentistry.

Q: As a dentist, do you like to embrace new technology?

A: I love what advances in technology have done for dentistry! Since the beginning of my career, I have been fascinated with modern dental technology. I computerized my office using software that came on a 3-inch floppy disk before Dentrix started, bought my first digital x-ray system from a very young Schick himself, and purchased my first AccuCam out of the San Fernando Valley garage of its inventor. When I bought my first digital panoramic machine, Orthophos (Sirona), I was told it was one of the first 10 in the country. I have similar stories with lasers, microabrasion units, and other technologies. In each room of my practice, we currently have the Galileos (Dentsply Sirona) and CEREC (Dentsply Sirona) lasers, the PrepStart H2O Microabrasion unit (Zest Dental Solutions), and intraoral cameras. As an early adopter of technology, I have realized that very few pieces really live up to their initial expectation of making dentistry easier, faster, and better.

Q: Do you believe that the in-office CAD/CAM machines are contributing to minimally invasive dentistry (MID)?

A: CAD/CAM machines have the potential to do so, but the answer is not at this point in time. Surprisingly, they are used predominantly for full crowns. I say this based on my conversations with hundreds of users as well as my experience with the training offered by the manufacturers and well-known teaching institutes, which focus on aggressive crown preparations driven by the alleged machine’s needs. Historically, in-office CAD/CAM machines had limitations with scanning and milling, requiring crown preparations with deeper chamfer margins and aggressive proximal separations, thus encouraging more aggressive preparations. With recent changes, scanners and milling units have mostly overcome those limitations. Like subgingival margin placement and mechanically retentive preparations, old habits die hard, even in academia. For the past 12 years, the Los Angeles Institute of Clinical Dentistry has strongly discouraged aggressive crown preparations and promoted advanced adhesion and supragingival MID. Conservative dentistry can be achieved with current CAD/CAM technology. We teach this in our workshops.

Q: Do you feel that in-office CAD/CAM technology makes dentistry better, faster, and easier?

A: I believe that, in the right hands, it has the potential to provide excellent quality same-day dentistry for patients. An in-office CAD/CAM machine is really a computerized laboratory that produces restorations that require in-office finishing. If the dentist likes and/or has some foundation in dental laboratory work (most do not, by the way), or is lucky to have a staff member who has lab experience, the restorations can be of good quality. In my opinion, an experienced dental technician can still produce better and more detailed restorations. Because a CAD/CAM machine adds the responsibility of producing good quality restorations to a dental office, if the team is not laboratory experienced or skilled, the overall restorative procedure may be of poorer quality when compared to the work delegated to a skilled dental laboratory team. When you add to the above advice by trainers and educators who promote aggressive preparations, as previously discussed, it could lead to less than ideal results. Unfortunately, I see a lot of this happening at some of these large dental clinics and dental chains where CAD/CAM machines are made available to inexperienced dentists and improperly trained in-office teams with the idea of saving money and satisfying the patients’ immediate-gratification needs.

Q: How do you feel about direct composite restorations versus CAD/CAM inlays?

A: Any type of indirect inlay requires more tooth removal compared to properly done supragingival MI direct composite restorations, and with all the negative consequences of more aggressive tooth removal. If the tooth structure can support an inlay, a direct inlay (direct composite) will always be a better choice. It will be healthier, more MI, less expensive, and have similar or better durability than a CAD/CAM restoration or any other lab-fabricated inlay. Of course, when the damage to the tooth is more extreme and the cusps are weak, fractured, or missing, a partial coverage onlay is needed and, when indicated, is still a better choice over a full crown. Some CAD/CAM educators promote the idea that CAD/CAM inlays can replace all direct Class II composite restorations. In my opinion, this is a mistake, as it goes in the opposite direction from a MI approach to dental care and is not best for our patients.

By using the most current knowledge on adhesive dentistry and supragingival preparation principles, a clinician can prepare and finish a simple MI Class II in 10 to 15 minutes, providing a faster, better, and healthier restoration for their patients than an aggressive indirect CAD/CAM inlay. More information on these techniques are described in my book (with contributing editor, Dr. Ray Bertolotti), Supra-Gingival Minimally Invasive Dentistry: A Healthier Approach to Esthetic Restorations (Wiley).

Q: Would you say a CAD/CAM is for every office?

A: Not at this time, but they are getting better and better! Owning this technology can be a real plus for marketing reasons. I am fascinated with CAD/CAM technology, but I must temper that fascination with lots of experience as a real world, full-time clinician trying to implement this technology into my practice. I have been involved and have used CAD/CAMs for close to 20 years now. I personally think the manufacturers of this practice-changing technology should allocate more resources to better train doctors and in-office chairside teams to ensure better quality MID and in an effort to minimize the number of more aggressive full-crown preparations currently being done. The technology is very good, but we need to see an increased level of the commitment to training and proper implementation, including an emphasis on MI treatment.

Dr. Ruiz practices in Los Angeles, and he is the director of the Los Angeles Institute of Clinical Dentistry and of many continuing education courses at the University of Southern California. He is an associate instructor at Dr. Gordon Christensen’s PCC (Utah) and an independent product evaluator for CR Foundation. He can be reached at (818) 558-4332 or via

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