Hard dental tissues laser welding: a new help for fractured teeth? A preliminary ex vivo study

An important surgical goal is to provide a first intention wound healing without trauma produced by sutures and for this aim in the past several methods have been tested. The aim of this ex vivo preliminary study was to demonstrate the capacity of a 1070 nm pulsed fiber laser to treat the dental fractures by enamel and dentine melting with the apposition of hydroxyapatite nanoparticles as filler.

Out of thirty freshly-extracted human third molars, decay-free, twenty-four cylinders of 5 mm thickness were obtained to perform the test.The device used was a 1070 nm Yb-doped pulsed fiber laser: this source has a maximum average output power of 20 W and a fixed pulse duration of 100 ns, while the repetition rate ranges from 20 kHz to 100 kHz. The samples were divided in three groups (a, b, c) of eight teeth and each specimen, with the two portions strictly placed side by side, was put inside the box and irradiated three times, the first and the second at 30 kW and the last at 10 kW peak power (average powers of 60 and 20 W).The repetition rate was maintained at 20 kHz for all the tests as well as the speed of the beam at 10 mm/sec.The samples of the group a were irradiated without apposition, in the group b nanoparticles (< 200 nm) of hydroxyapatite were put in the gap between the two portions while in the group c, a powder of hydroxyapatite was employed.

Only the specimens of the group b showed a real process of welding of the two parts, while specimens of groups a and c did not reach a complete welding process.

This ex vivo preliminary study, based on the enamel and dentine welding obtained by a 1070 nm pulsed fiber laser associated to the hydroxyapatite nanoparticles, may represent a new and original approach for the treatment of the fractured teeth, even if further studies will be necessary to confirm these results.