Todor Petrov1, Emilia Pecheva2, Anthony D Walmsley3, Stefan Dimov4. 1. Institute of Solid State Physics "Georgi Nadjakov", Bulgarian Academy of Sciences, Sofia, Bulgaria; Department of Applied Physics, Faculty of Applied Mathematics and Informatics, Technical University of Sofia, Bulgaria; Department of Mechanical Engineering, University of Birmingham, United Kingdom. 2. Institute of Solid State Physics "Georgi Nadjakov", Bulgarian Academy of Sciences, Sofia, Bulgaria; School of Dentistry, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B5 7EG, United Kingdom. Electronic address: emily@issp.bas.bg. 3. School of Dentistry, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B5 7EG, United Kingdom. 4. Department of Mechanical Engineering, University of Birmingham, United Kingdom.
Abstract
PURPOSE: The purpose of the present work was to achieve fast and more precise ablation in dentin and enamel by using a commercial femtosecond laser system with high repetition rate, whilst avoiding any collateral irreversible damages in the hard tissue and pulp area. METHODS: We used fluence of the incident laser pulses which was marginally higher than the ablation threshold for dentin and enamel. The study was based on the hypothesis that femtosecond laser operating with a repetition rate in the range of 100-500 kHz can controllably ablate dental tissue obtaining sufficiently high removal rate whilst avoiding any collateral irreversible damages in the hard tissue and pulp area. RESULTS: The ablation yielded the formation of 1 mm3 craters with well-defined precise vertical cavity sides and edges. Advantageous high porosity and numerous interconnected pores were introduced in the ablated zones. Thermal load and hence collateral thermo-mechanical damages were avoided and the crystalline structure of the tooth constituent hydroxyapatite was preserved. CONCLUSION: The ultrafast femtosecond laser used in our work hold the promise of a significant drilling ability without collateral thermomechanical effects. It achieves high processing efficiency, overcomes disadvantages of other laser systems reported and can be used to develop an instrument for cavity preparation based on fast and precise ablation. Our further aim is to exceed the speed of traditional drilling instruments and thus to reduce the treatment time which in turn will bring comfort to the patient.
PURPOSE: The purpose of the present work was to achieve fast and more precise ablation in dentin and enamel by using a commercial femtosecond laser system with high repetition rate, whilst avoiding any collateral irreversible damages in the hard tissue and pulp area. METHODS: We used fluence of the incident laser pulses which was marginally higher than the ablation threshold for dentin and enamel. The study was based on the hypothesis that femtosecond laser operating with a repetition rate in the range of 100-500 kHz can controllably ablate dental tissue obtaining sufficiently high removal rate whilst avoiding any collateral irreversible damages in the hard tissue and pulp area. RESULTS: The ablation yielded the formation of 1 mm3 craters with well-defined precise vertical cavity sides and edges. Advantageous high porosity and numerous interconnected pores were introduced in the ablated zones. Thermal load and hence collateral thermo-mechanical damages were avoided and the crystalline structure of the tooth constituent hydroxyapatite was preserved. CONCLUSION: The ultrafast femtosecond laser used in our work hold the promise of a significant drilling ability without collateral thermomechanical effects. It achieves high processing efficiency, overcomes disadvantages of other laser systems reported and can be used to develop an instrument for cavity preparation based on fast and precise ablation. Our further aim is to exceed the speed of traditional drilling instruments and thus to reduce the treatment time which in turn will bring comfort to the patient.
Authors: Reinhard E Friedrich; Maria Quade; Nate Jowett; Peter Kroetz; Michael Amling; Felix K Kohlrusch; Jozef Zustin; Martin Gosau; Hartmut SchlÜter; R J Dwayne Miller Journal: In Vivo Date: 2020 Sep-Oct Impact factor: 2.155