Two-dimensional changes and surface characteristics from an erbium laser used for root canal preparation

Lasers Surg Med. 2010 Jul;42(5):379-83

Roper MJ, White JM, Goodis HE, Gekelman D.

Division of Endodontics, Department of Preventive and Restorative Dental Sciences, University of California School of Dentistry, San Francisco, California 94143-0758, USA.

Abstract

BACKGROUND AND OBJECTIVE:
Erbium lasers have been advocated for use in root canal because of their ability to ablate dentin and remove biologic debris in the root canal space. This study evaluated the ability of an Er:YAG laser to remove dentin predictably in the root canal system and its cleaning ability.

STUDY DESIGN/MATERIALS AND METHODS:
Twenty-eight single-rooted extracted teeth were assigned into two groups. The first group was cleaned and shaped using crown-down technique with GT rotary files (control). The second group used an Er:YAG laser with ceramic tip, above the dentin ablation threshold for root canal shaping. A separate group of three teeth was evaluated for cleanliness using an Er:YAG laser with spiral tips. Amount of dentin removed in the buccal-lingual and mesial-distal directions was measured, the data analyzed by ANOVA. Surface characteristics were qualitatively examined.

RESULTS:
The control group produced cleaner, better shaped root canals, faster than the Er:YAG group. The Er:YAG group removed more dentin in the coronal portion but less in the middle and apical thirds. The Er:YAG with spiral tip group left a dense smear layer in the middle and apical thirds. The Er:YAG group was subject to procedural errors more often than the control group.

CONCLUSION:
The Erbium laser studied was equivalent to rotary files in the coronal and middle thirds but not in the apical thirds of the root canal system.

Temperature rise of the post and on the root surface during ultrasonic post removal

Budd JC, Gekelman D, White JM.

Int Endod J. 2005 Oct;38(10):705-11.

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2591.2005.01002.x/full

Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California, San Francisco, CA, USA.

Abstract

AIM:
To determine the temperature rise on the root surface caused by ultrasonic post removal using different devices and techniques in a laboratory setting.


METHODOLOGY:
Two ultrasonic devices, one piezoelectrical (Pi) and one magnetostrictive (Ma), were investigated. A serrated titanium post was placed into the distal root canal of a human mandibular first molar. Four coolant parameters were utilized: no air, no water, no evacuation (NN), air only with high-speed evacuation (A), 15 mL min(-1) water coolant with high-speed evacuation (W15) and 30 mL min(-1) water coolant with high-speed evacuation (W30). Five simulated post removals were measured at two locations, the post (P) and the root (R), for each coolant parameter. Temperature rise was measured at 30, 60, 90 and 120 s intervals using calibrated infrared thermography (n = 80). Temperatures were recorded at 45 ms intervals. Data were analysed using repeated measures anova with the Scheffe post hoc test (P < or = 0.05).
RESULTS:
The overall mean pooled effect showed that temperature rise for P = 20.1 +/- 27.9 degrees C and R = 10.9 +/- 7.9 degrees C were significantly different. Significant differences in temperature rise were: Pi > Ma, P > R, NN > A = W15 = W30 however, A > W30.

CONCLUSIONS:
There were significant differences in temperature rise as a function of ultrasonic device, location on the tooth and cooling method utilized for post removal.

Happiness is a root canal treatment: achieving predictable success in Endodontics!

Following the proper steps is key to success in Endodontics. No step can be neglected; mishaps in each step will preclude the successful accomplishment of the next one.
Establishing a correct diagnosis is critical and it can be accomplished performing thorough clinical and radiographic exam, including all tests needed. Cutting edge technology, such as, laser Doppler and Cone beam CT scanner are available nowadays to aid the clinician establish the correct diagnosis.
Once a definitive diagnosis is established, endodontic therapy can be initiated. The access cavity with straight line access will facilitate the location of all root canal orifices and the correct cleaning and shaping of the whole root canal system.
Cleaning and Shaping: once an appropriate access cavity has been created, root canals are mechanically and chemically cleaned through the use of files and irrigants, often in combination with ultrasonic activation. Sodium hypochlorite, chlorhexidine and EDTA have all precise indications for use during the cleaning and shaping phase, which aims to eliminate all potential irritants including pulp tissue, debris, microorganisms, and other pathogens, thus achieving clinical success.
After thorough cleaning and shaping, the root canal system needs to receive an hermetic seal, a complete obturation, in order to minimize empty spaces within the root canal system where microorganisms may recolonize, to entomb potentially remaining debris and bacteria, creating a complete seal along the entire length of the root canal. Research has shown that remaining bacteria that survive after cleaning and shaping quickly proliferate and recolonize root canals that remain poorly obturated or empty.
In summary, following carefully each and every step of root canal therapy will result in predictable and successful outcomes, corroborating a rewarding and pleasant experience for both, patient and clinician!
Happiness is a well executed root canal treatment!