(71) In-vitro Study of Laser-Assisted Prefabricated Ceramic Crown debonding as compared to Traditional Rotary Instrument Removal

Introduction: Facilitating crown removal with laser offers a non-invasive alternative to rotary instruments for ceramic crowns. The aim of this in vitro study is to compare the laser-assisted and rotary retrieval of ceramic crowns cemented with resin-modified glass ionomer (RMGI) cement and assess retrieval time and pulpal temperature changes for two different techniques.
This in-vitro study aimed to compare the laser-assisted and rotary retrieval of prefabricated zirconia crowns cemented with RMGI from permanent posterior teeth and assess the time required and temperature changes.

Methods:

Methods: This in-vitro study used extracted permanent posterior teeth (N=13) prepared and restored with prefabricated zirconia crowns (NuSmile®, Houston, TX, USA) cemented with RMGI. Crowns were removed using an air-rotary handpiece and or Er,Cr:YSGG laser. Differences in removal time and pulpal temperature were compared based on the method of removal with equal and unequal variance t-tests. The significance level was set at 0.05 level. A specimen for each technique underwent SEM examination.

Results:

Results: Thirteen posterior crowns were removed with laser and drill (26 removals). The average time for crown removal with a rotary handpiece was 114.2 seconds (SD=32.1) with the handpiece and 288.5 seconds (SD=76.1) with the laser. Removal with the laser took significantly longer, by an average of 174.2 (95% CI: 127.0-221.5, p-value < 0.0001) and had higher variability than the rotary handpiece (p-value=0.0056).
Laser-assisted crown removal was associated with a maximum temperature of 4.0⁰C (95% CI: 3.4-4.7) higher than with the drill (p-value < 0.0001). The maximum observed temperature with the drill was 21.8⁰C (SD=0.77) compared to 25.8⁰C (SD=0.85) with the laser. . The laser was not associated with significantly different variability (p-value=0.7192).

Conclusions:

Conclusions: Er,Cr:YSGG laser and rotary handpiece can both be used predictably to remove zirconia crowns from primary anterior teeth. While a rotary handpiece presents a more efficient method of removal, Er,Cr:YSGG laser offers a viable alternative method.

Lead Author's Contributions to the Research Project. : Conceptualization, methodology, analysis, writing, composition of the abstract