Eradicating the endodontic enemy — bacteria — utilizing ZEISS microscopy and EndoHandle

Dr. Lauren Kuhn writes about how Zeiss products give endodontists the proper vision to win the war against bacteria.

Dr. Lauren E. Kuhn discusses her bacteria-battling techniques

If endodontics were combat, endodontists would be highly decorated warriors.

We need capable “boots on the ground” to win battles against bacteria. The war against bacterial colonization of the root canal system — and apical periodontitis — is comprised of many battles. To ultimately win the war, we need strategy, proper equipment, and vision.

Here are some bacteria-fighting strategies.

Figures 1A and 1B (left): Images taken through microscope (ZEISS EXTARO 300). 1A. Extracted premolar with access preparation. Preparing to enter access with pre-curved size 10 C-File on Universal EndoHandle (Venta Endo). 1B. Tactile exploration of the access with size 10 C-File on Universal EndoHandle (Venta Endo); Figure 2 (right): Caries visualized during microscopic examination (ZEISS EXTARO 300)

Strategy 1: Get a bird’s eye view

It’s hard to fight what you can’t see. After initial access, tilting the microscope head or objective lens aids in visualization. In my experience, ZEISS EXTARO® 300 simplifies these adjustments. Likewise, with the ZEISS OPMI® pico, the MORA interface allows me to tilt the objective lens left and right.

Also, a clinician can scout inside the access without obstructions. The Universal EndoHandle (Vental Endo) grasps hand files and gives an unobstructed view. It’s like a DG-16 explorer and a hand file joined forces. After initial access, I focus with my microscope and deploy an EndoHandle to scout for symmetry, orifices, isthmuses, pulp tissue, etc. To see a perforation or open margin, I place the EndoHandle in the area and attach the apex locator to see if my file is in contact with the periodontium. The initial scouting is remarkably easier with a good view (microscope) and my hands out of the way (EndoHandle).

Figures 3A and 3B: Images taken through microscope (ZEISS EXTARO 300). 3A. Extracted maxillary molar. Exploring for MB1 canal. Debris visible in pulp chamber. 3B. Exploring for MB2 canal

Strategy 2: Identify peripheral threats

Bacteria are lurking in caries, as well as the canal system!

On the EXTARO 300, Fluorescence mode and NoGlare mode aid in caries detection and viewing subtle details. On the ZEISS OPMI PICO, the MORA interface allows me to view the periphery without sacrificing ergonomics, by tilting the objective lens left and right.

Figures 4A-4C: Images taken through microscope (ZEISS EXTARO 300). 4A. Small drop of lubricant on file tip, attached to Universal EndoHandle. 4B. File and lubricant placed precisely into orifice of interest (radix paramolaris case). 4C. The EndoHandle is used in a longitudinal filing motion to deliver the lubricant into the canal

Strategy 3: Identify bacterial strongholds

To zoom in and identify critical bacterial fortresses, I adjust the microscope’s magnification and fine focus to get a high-definition view of the pulp chamber and orifices. The Universal EndoHandle (Venta Endo) allows exploration of the landscape without obstruction.

Pre-curving the file on the EndoHandle gives precise and directed entry to the orifices(s). It’s a game changer for canals that require angular entry (such as MB of tooth No. 30) and for ambushing bacteria’s hiding places, such as fins, isthmuses, and additional canals.

Strategy 4: Ensure precision

Achieving patency can be challenging on calcified or curved canals. In difficult skirmishes, I deploy lubricant (such as RC Prep). However, the lubricant often smears onto the walls and obstructs my view. To prevent this, I place a small drop of lubricant on a pre-curved file on the EndoHandle (Venta Endo) and precisely place the lubricant into the desired location. Longitudinal filing with the EndoHandle delivers the lubricant to mid-root level.

Strategy 5: Seize remaining supplies

The key to a successful battle is to attack from all angles. The aim is to mechanically (hand and rotary files) and chemomechanically (irrigation) remove and kill bacteria. But stragglers lurk in nearby crevices or caverns, and remaining supplies (pulp tissue) could nourish loiterers. It’s important make the environment inhospitable for occupation.

My ZEISS microscopes allow me to adjust my focus down the canals. I identify remaining supplies (pulp tissue, debris), blockades (such as pulp stones), and channels (such as cracks) that could harbor bacteria.

It’s hard to fight an enemy you can’t see. With proper vision, the war can be won.


The opinions and techniques shown here are the recommendations of Dr. Kuhn. ZEISS does not dispense medical advice. Clinicians should use their own judgment in treating their patients. This article was supported by ZEISS.

Zeiss provides the tools for more predictable root-end surgeries. Read this article by Dr. Jon Irelan to find out more.

Lauren E. Kuhn, DMD, MSD, is a graduate of the Harvard School of Dental Medicine (DMD) and Medical University of South Carolina (MSD in Endodontics). She is passionate about education and currently teaches part-time at the University of Minnesota School of Dentistry. She has published case-based research in the Southeast Case Research Journal and coauthored literature reviews in Dental Materials and The Journal of Advanced Prosthodontics. In addition, Dr. Kuhn’s research on patient motivation was featured in RDH Magazine in 2019. Aside from her research activities, Dr. Kuhn works as a full-time clinical endodontist.

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