Being a dentist for 38 years (Marquette School of Dentistry, 1986), I have seen a lot of changes in how we practice dentistry since I attended dental school. Back then, we were taking hydrocolloid impressions, developing radiographs with chemicals, and were just starting to place posterior composites. Implants were in their infancy. Fast forward, dentistry has changed just a little (actually a lot) in the last 30 years. Digital radiographs, scanning, in-office milling, and implants are commonplace in today’s dental practice.
Technology is amazing, providing easier, better solutions to create clinically superior outcomes for our patients. Through dental material research, we can create superior, longer-lasting esthetic restorations for our patients. Zirconia and Emax ceramic materials have replaced porcelain-fused-metal (PFM), creating more natural results without having to worry about hiding metal margins or metal showing through the porcelain. With this change has come a little problem: as we are placing more and more ceramic restorations and replacing existing PFMs, there is a need to remove existing ceramic restorations (veneers and crowns) without damage or fracture to the underlying tooth. This can result in cutting into tooth structure or, worst-case scenario, causing the underlying tooth to fracture, resulting in the tooth having to be extracted. The most common traditional way we remove resin-bonded ceramic restorations is with a high-speed drill and bur. Often called the “rule of eight,” we cut the existing restoration in half and try to remove it while trying not to fracture the tooth. (Beware of lower molars that are endodontically treated.) When that does not work, we cut it into fourths, and when that does not work, we cut it into eighths, chipping away at the remaining pieces. Sometimes we have to re-prep just to get the entire restoration off. We usually go through a few diamond burs, and it creates a lot of stress. When we finally remove all the old zirconia crown, again hopefully without fracturing the remaining tooth/root, we breathe a sigh of relief.
This could be one of my least favorite/stressful clinical procedures I do, and I am sure many of you agree. For years, I have been thinking there must be a better, less stressful way to remove ceramic restorations, and now luckily, there is. As we know, technology is constantly evolving in dentistry, and laser technology has become commonplace for clinical procedures. Lasers have evolved from slow-cutting, bulky machines to powerful, sleek, intuitive tools that can be used in a surprising amount of day-to-day clinical procedures. From soft tissue surgery to hard tissue procedures (cutting tooth and bone), as an adjunct to periodontal therapy and endodontic disinfection, lasers have become the standard of care in providing cutting-edge treatment for our patients. With numerous applications and easy-to-use touch screen interfaces, lasers are a tool that can be utilized every day to provide a wide range of procedures, including removing ceramic veneer and ceramic crown restorations while minimizing the risk of damaging the underlying tooth/root structure.
Sounds too good to be true, so in this clinical article, I will present cases in which an Er, Cr: YSGG laser was used to remove an existing veneer, a zirconia crown, and a 3-unit zirconia bridge. This article will demonstrate an alternative to cutting off ceramic restorations with a high-speed drill and bur.
THE SCIENCE BEHIND HOW THIS WORKS
Er, Cr: YSGG laser energy is transmitted through the ceramic or porcelain material and interacts with the underlying cement, as depicted in Figure 1. The wavelength is absorbed in the polymer matrix of the adhesive cement. Based on scientific literature, the mode of action on the cement is a combination of photochemical changes and differing heat expansion coefficients. These results predicted that erbium laser energy would be transmitted through ceramic and would be absorbed in the resin cements. The study also confirmed that the threshold for laser-cement interaction resulted in “fuming” or heat deterioration first, and then ablation of the cement at higher fluences, 2.6-4.7 J/cm². On a microsecond scale, the laser energy superheats the cement, expanding the volume, and breaking the bond between the adhesive and the cement or porcelain. Performing this interaction over the full surface of the crown or veneer dislodges the restoration.
LASER VENEER AND CROWN REMOVAL TECHNIQUE
Once the YSGG laser is set up, the touch screen is utilized to navigate to the veneer and crown removal setting. The parameters are adjusted to the selected tip (I use an MZ8-6mm), to 4.0 watts 20 Hz, 50 air/50 water for the veneer removal procedure and 6.0 watts 20 Hz, 50 air/50 water for the crown removal procedure. The laser is placed in ready mode and activated outside the mouth to confirm air/water output (similar to stepping on the rheostat with a high-speed drill to confirm water spray) before placing the drill into the patient’s mouth.
The tip is then placed 1-2 mm from the veneer/crown surface, and the surface is slowly/methodically painted with the laser energy. Suction is utilized to remove water spray. The entire surface needs to be “painted” with the laser energy, buccally, lingually, interproximally, and in the case of posterior crowns, occlusally. This procedure should take only approximately 1 minute for a veneer and 2 minutes for a full coverage restoration. If the restoration does not release, try utilizing a scaler or spoon excavator to “catch” a margin/edge on a veneer or a temporary crown removal pliers for a full coverage crown. If unsuccessful, repeat the process. In rare cases when this does not remove the restoration, you may have to still cut it off, but usually it only takes 1 cut to remove. (Work on technique, slowly paint the entire surface.)
CLINICAL CASES
These clinical cases will demonstrate utilizing an Er, Cr: YSGG laser to facilitate the removal of various ceramic restorations with less possible damage to the remaining tooth structure or, in the case of the 3-unit zirconia fixed partial denture (FPD), utilizing the removed bridge as a temporary.
Case #1: The patient presents with a fractured lower anterior veneer. (Figure 1)
Figure 1.
The laser is used as described in the technique section and the veneer is removed in about 20 seconds. (Figure 2)
Figure 2.
Case #2: The patient presents with a poorly contoured full coverage Emax restoration on #10. (Figure 3)
Figure 3.
Because the tooth has been endodontically treated, there are concerns about possible fracture to the remaining tooth structure with conventional removal methods. Removal of the ceramic crown in one piece with no damage to the remaining tooth structure. (Figure 4)
Figure 4.
Case #3: The patient presents with a 3-unit zirconia FPD. Following placement, the patient developed a sinus communication in the prior extraction site and the OS requested the FPD be removed to access and repair the defect. (Figure 5)
Figure 5.
The clinician wanted to preserve the FPD by removing it intact, utilizing it as a temporary and then recementing the FPD once the sinus communication was repaired and healed. The FPD was removed. (Figures 6 and 7) Note the discoloration on the underlying tooth structure, which is easily removed by pumice or a fine diamond bur. Also, the discoloration on the inside of the FPD, which again can be easily removed utilizing a lab micro edger. Once cleaned (Figure 8), the FPD is reseated and recemented with temporary cement. (Figure 9)
Figure 6.
Figure 7.
Figure 8.
Figure 9.
These are some of the everyday cases in which laser veneer, crown, and FPD removal could provide a safe alternative, and in some cases retaining the restoration, compared to conventional methods.
VARIABLES AND COMMONLY ASKED QUESTIONS
- What if the veneer or crown is chipped or has fracture lines? If these conditions are present, there is a good probability that the restoration will still be removed but could fracture and not be removed in one piece.
- Can this technique be utilized for PFM restorations? No, the laser energy will not penetrate through the metal.
- What if after 2 attempts the restoration does not separate from the tooth? Due to variables in cement or thickness of the restoration, sometimes the restoration will need to be mechanically cut off utilizing a high-speed drill. If this occurs, the amount of effort to cut it off will be greatly reduced (usually sectioning into 2 pieces then popping it off, no multiple cuts to remove the restoration).
- Can this technique be utilized to remove zirconia crowns cemented to an implant abutment or ceramic orthodontic brackets? Yes, utilize the veneer removal setting, 4.0 watts, 20 Hz, 50 air/50 water.
CONCLUSION
While there are numerous methods to remove existing failing Emax and zirconia restorations—crown removal devices, ‘Gummies,’ the probably the most utilized, sectioning with a bur—these techniques are unreliable, time-consuming, and can result in damage to the tooth or render the restoration unusable. Laser technology can provide a safe, quicker alternative to traditional methods, and in many instances, preserve the existing restoration. Not only saving time and money (fewer burs used), but also possibly using the removed restoration as your temporary. While variables in cementation and the existing restoration (thickness, cracks) can factor in the results, this technique has been found to facilitate the removal of ceramic restorations efficiently and in most instances without damage/fracture to the existing tooth structure. Factors that improve clinical results include proper laser setting, proper distance from the restorative surface, and proper movement, slow and methodical.
REFERENCES
- Deeb, Janina Golob, Connor McCall, Caroline K. Carrico, William O. Dahlke, and Kinga Grzech-Leśniak. “Retrieval of Prefabricated Zirconia Crowns with Er,Cr:YSGG Laser from Primary and Permanent Molars.” Materials 13, no. 23 (December 7, 2020): 5569. https://doi.org/10.3390/ma13235569.
- Golob Deeb, Janina, Lenart Skrjanc, Domen Kanduti, Caroline Carrico, Andrea Saturno, and Kinga Grzech-Leśniak. “Evaluation of Er:YAG and Er,Cr:YSGG Laser Irradiation for the Debonding of Prefabricated Zirconia Crowns.” Advances in Clinical and Experimental Medicine 30, no. 1 (February 2, 2021): 7–15. https://doi.org/10.17219/acem/127686.
- McCall, Connor W. “Non-Invasive Retrieval of Prefabricated Zirconia Crowns with Er,Cr:YSGG Laser from Primary and Permanent Teeth.” Virginia Commonwealth University, 2020.
- Phillips, Wesley Blake. “Thermal Changes in the Dental Pulp During Er,Cr:YSGG Laser Removal of IPS e.Max Press Lithium Disilicate Veneers.” Ohio State University, 2012.
- Broome, Patric. “Utilization of an Er,Cr:YSGG Laser for the Removal of All-Ceramic Restorations.” Pract Proced Aesthet Dent. 19, no. 1 (2007): 3.
- Abdel Sadek, Hoda M., Ahmed M. Abdel Khalek, and Marwa M. Wahsh. “The Effect of Er, Cr:YSGG Laser Debonding on the Bond Strength of Two Ceramic Materials to Dentin.” BMC Oral Health 23, no. 1 (January 12, 2023): 17. https://doi.org/10.1186/s12903-023-02721-9.
- Lawson, Nathaniel, Frazier, Bedran-Russo, Park, Urquhart. “Zirconia Restorations: An American Dental Association Clinical Evaluators Panel Survey”. JADA VOLUME 152, ISSUE 1, P80-81.E2, JANUARY 2021 https://doi.org/10.1016/j.adaj.2020.10.012
- Kellesarian, Sergio Varela, Vanessa Ros Malignaggi, Khaled M. Aldosary, and Fawad Javed. “Laser-Assisted Removal of All Ceramic Fixed Dental Prostheses: A Comprehensive Review.” Journal of Esthetic and Restorative Dentistry 30, no. 3 (2018): 216–22. https://doi.org/10.1111/jerd.12360.
ABOUT THE AUTHOR
Dr. Michael Koceja graduated from Marquette University School of Dentistry in 1986. He served 8 years in the United States Navy Dental Corps, where he completed a Periodontal Fellowship in San Diego in 1991. Dr. Koceja has been in private practice since 1994, and has been actively involved in the use of lasers in dentistry since 1999. He has lectured extensively on “General Dentist’s incorporation of lasers into their practices.”
Dr. Koceja received his laser certification in 2000, and has since achieved mastership level at the World Clinical Laser Institute. He has also tested various models of lasers, giving him a true comparison of what lasers can and cannot do. Dr. Koceja is actively involved in the W.C.L.I., including a position on the certification committee. He is presently practicing in Camas, Washington. Dr. Koceja has trained thousands of dentists and hygienists to use dental lasers, and has written numerous articles on lasers in dentistry. These include: “The atraumatic laser excision and ablation of mandibular tori,” “Everyday Dentistry,” ” The dermatological applications of a Dental Laser,” Lasers 101, and more.
Over the past 10+ years, Dr. Koceja has lectured throughout the world on lasers and their incorporation into all aspects of dental practice.
He has had the opportunity to present at pediatric, ortho, and aesthetic dental organization meetings throughout the country.
