Laser Focused by Dr. Fernando J. Meza

Laser Focused 

Transforming root canal treatment with dental lasers

by Dr. Fernando J. Meza

When patients hear the words “root canal,” fear is often the first emotion that comes up. And understandably so, because traditional root canal treatment requires delivery of local anesthesia, an extended amount of time in the chair, postoperative pain and long healing times.

Knowing this concern when I began my career in endodontics, I became passionate about finding the most innovative technologies to enhance treatments and redefine the dental experience for my patients. I’ve always been fascinated in the connection between dentistry and technology, and during my residency I explored the disinfecting capabilities of dental lasers on bacterially infected roots, focusing my research on the Waterlase iPlus all-tissue dental laser from Biolase.

After a long hiatus between my endodontic residency and years in private practice, I invested in the Waterlase iPlus because I believed it to be the most advanced and minimally invasive all-tissue dental laser system for endodontics diagnosis, and because I hoped it would improve my treatment of a variety of different cases. A tale of two root canal treatments You may be asking what makes performing root canals with a dental laser easier than the traditional method. I’ll share two cases—one performed before I adopted a dental laser, the other using the laser—to illustrate how treatment has evolved for single-visit endodontic treatment. This is a particularly interesting comparison because both diagnoses are the same and both teeth are on the same quadrant … and on the same patient.

In 2018, I diagnosed a patient with irreversible pulpitis with symptomatic apical periodontitis on #19 (Fig. 1). Because this was before I owned a dental laser, the root canal treatment procedure was performed with the traditional tools we’re all accustomed to: endodontic burs to open the inside of the tooth to reach the canals, ultrasonic files and long surgical-length burs to modify the endodontic access, stainless steel and rotary nickel titanium files to negotiate and enlarge the root canal anatomy.
Dental Laser Focused
Fig. 1

The procedure for #19 (Fig. 2) was deemed a success at a four-year follow-up visit, based on a preoperative CBCT taken for #18 that was beginning to bother the patient. It happened to be that #18 was also diagnosed with irreversible pulpitis with symptomatic apical periodontitis (Fig. 3), but the year was 2022. One key difference at this time was that I had two years of experience with the dental laser.
Dental Laser Focused
Fig. 2
Dental Laser Focused
Fig. 3

A review of the CBCT showed absolutely no PA pathology and all canals properly filled for #19. There was no current PA pathology for #18.

An interesting finding that plagues every endodontist but is encountered only every once in a while was that the patient reported no pain when biting, but there was a side-directed tenderness from the buccal aspect when I pressed on #19 with my finger. In certain cases this can be inconsequential, but for others it can lead to having to re-treat the case or the need to perform apical surgery.

It is difficult to attribute a direct cause to this phenomenon. Some endodontists believe the side-directed pressure tenderness after root canal treatment may be caused by a crack, a traumatic occlusion or a patient who has chronic pain, to name just a few suggestions. While these reasons may be true, I believe the issue is mostly caused by a failure of the irrigating solution to reach the apical ends of the tooth to properly clear all of the tissue and infected dentin debris. I point this out because thanks to dental laser technology, we are seeing less side-directed tenderness on particularly vital cases.

Referencing the images provided, we can see that the distal apical portion of the root of #18 is filled very nicely (Fig. 4). The dental laser allows for more conservation of tooth structure and better management of the apical end of the tooth, considering the curvature while still allowing for the ability to fill the sealer and gutta percha nicely around the curve.
Dental Laser Focused
Fig. 4

In this case, the dental laser was used in conjunction with 2.5% sodium hypochlorite solution with the laser tip placed at midroot, bringing the photoacoustic effect closer to the apical and middle portions of the root to better debride the canal of dentin debris and apical tissue.

Apical deltas, accessory canals and lateral canals
In the previous cases, we compared the difference in cleaning and shaping between a more traditional technique and a laser-assisted endodontic technique with the dental laser. While both techniques work well, the laser advantage is such that a more conservative approach deviating less from the original anatomy may prove to be beneficial and a step in the right direction as we consider the evolution of endodontic treatment. No longer do we need to play the role of apical barbarian and rely heavily on mechanical instrumentation; we have another tool at our disposal.

While the previous case showed a nice apical fill and a more conservative approach, let’s get more specific in terms of which type of anatomy we’re trying to clean and fill. Notice that I mentioned only clean and fill, not clean and shape and fill. As you start using a laser in endodontics, you begin to recognize that you don’t have to rely as much on mechanical instrumentation. In fact, how were we ever supposed to curve a file into a lateral canal or small accessory canals?

At long last, with the assistance of dental lasers, the cleaning of these small ramifications is possible. Let’s look at the premolar case on the preand postoperative images in Figs. 5 and 6. Several ramifications from the main canal appear to be filled in this vital case. While filling of these tiny regions is more common in necrotic cases, probably because of the degeneration of the pulpal tissue remnants leaving hollow spaces, they are less commonly filled in vital cases but just as important to debride and disinfect. Again, the dental laser gives us a chance to do just that.
Dental Laser Focused
Fig. 5
Dental Laser Focused
Fig. 6

Better-filled canals: The unpredictable MB and MB2 canals
In the final case illustrated, the maxillary first left molar (Fig. 7), we will explore the enhanced dentin debris removal capabilities of the Waterlase iPlus laser. Deep inside our endodontic memory bank are Vertucci’s eight classifications of canal configurations. I’m sure at one point during my residency I could draw them all out and describe them in perfect detail. After many years of private practice, and completing case after case, you pretty much just remember that maxillary first molars almost always (93%–95.2% of the time1,2) have two canals in the mesiobuccal root: MB and MB2. The MB2 canal is also referred to as the ML canal for its slight lingual or palatal position with respect to the MB canal. CBCT imaging has made the presence of both MB and MB2 glaringly visible, if present, and has eliminated a lot of the guesswork and time that used to occur during treatment striving to find both canals in the MB root.
Dental Laser Focused
Fig. 7

Knowing that both canals are present is just half the battle. Now comes the challenge of instrumenting two canals that may join at any place in the MB root, creating isthmuses and abrupt curvatures that can quickly humble even the most seasoned endodontist. The powerful photoacoustic effect created by the dental laser within the canals provides for unparalleled and safe removal of dentin debris in any maxillary tooth, even when the apex or apices are close to the sinus membrane.

By placing the specially designed, ultrasmall, radial firing tip 2 (RFT2) adapted for the Waterlase, you have complete control and ease of placement within the canal to deliver the cavitation effect that will flush out dentin debris from the main canal into the chamber.

Because the diameter of the RFT2 tip is only 0.2 mm—the size of a #20 stainless steel file—it works particularly well within very small canals such as the MB and MB2. The use of the RFT2 tip with 2.5% sodium hypochlorite solution in conjunction with rotary files makes for a very powerful technique that allows for enhanced tissue dissolution between canals and enhanced removal of the dentin debris that’s a byproduct of rotary instrumentation (Fig. 8).
Dental Laser Focused
Fig. 8

As a testament to the technique, sealer is often visible in the second orifice as it is first placed into one of the canals. This is because of patent connections that are established with the Waterlase and its cavitation effect.

Sometimes, unexpected surprises are noticed in the canal configuration if on occasion you take a postoperative CBCT of your immediately filled case or on the follow-up visit of the same case. In this case, the coronal view of the postop CBCT image taken at just four months (Fig. 9) shows very clearly the presence of two orifices that diverge into three independent apical portals of exit along the palatal to buccal dimension of the MB root. The axial view (Fig. 10, p. 48) further confirms this finding. Evidence of apical healing is already starting to take place. This is very exciting!
Dental Laser Focused
Fig. 9

The dental laser allows for better dentin and tissue debridement in conjunction with 2.5% sodium hypochlorite solution and rotary files. Better flow of the bioceramic sealer allows for a properly obturated case.

The best tool at my practice
Over the past two years, I can confidently say I have begun performing truly the best endodontics of my entire career, and I attribute much of this to the improved technology that we have with laser-assisted endodontics. Since adopting the dental laser, I am completing more than 95% of my cases in a single visit and performing more 3D filling of roots and apices—even in vital cases. I’m also seeing more predictability in treatments, less postoperative discomfort and, on occasion, faster healing.

I never could have imagined the impact that investing in a dental laser would have on my practice. Enhanced endodontic irrigation of the main canals is just the beginning; other uses include:
  • Soft-tissue applications such as gingivectomy, coagulation, incisions for apical surgery, periapical granuloma/cyst removal and treatment of sinus tracts.
  • Hard-tissue applications such as endodontic access; searching for and management of calcified canals; enhanced irrigation; disinfection of canal walls, accessory canals and dentinal tubules; laser patency; root resection; apical conditioning; and laser analgesia for hot teeth.
For all types of diagnoses—necrotic, vital and all the above—the enhanced capabilities of the Waterlase iPlus has expanded my practice’s opportunity to grow and remain competitive in offering patients the most innovative dental tools available.

1. Kulild JC, Peters DD. Incidence and configuration of canal systems in the mesiobuccal root of maxillary first and second molars. J Endod. 1990; 16:311–317.
2. Stropko JJ. Canal morphology of maxillary molars: clinical observations of canal configurations. J Endod. 1999; 25:446–450.

Author Bio
Dr. Fernando J. Meza Dr. Fernando J. Meza earned a bachelor’s degree in psychology before graduating from the University of Connecticut School of Dental Medicine in 2002 and earning a certificate in endodontics from Temple University School of Dentistry in 2004. During his residency, Meza researched the Biolase Waterlase all-tissue laser’s capabilities to disinfect bacterially infected roots. The research was published in the Journal of the American Dental Association (JADA) in July 2007. He has lectured for Biolase in hands-on courses and provided in-office training to endodontists and endodontic residents in the U.S. and Canada.
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