The evolution of cavitation in narrow soft-solid wedge geometry mimicking periodontal and peri-implant pockets

Biofilm removal from Difficult-to-Reach places via secondary cavitation within a constrained geometry mimicking a Periodontal/Peri-Implant pocket

“…The glass slide and PDMS block are inserted into the seat of the connecting frame and clamped with a 5 mm thick Plexiglas plate to prevent fluid from leaking from the sides of the pocket during the laser-induced cavitation experiments. PDMS (Dow Europe GmbH, Germany) was prepared as described previously [3] . We used two model tissues, 4 % PDMS, mimicking severely inflamed tissue and 10 % PDMS, mimicking healthy tissue.…”

“…To observe biofilm removal with photoacoustic irrigation in real time, an experimental setup was performed as described previously [3] . Briefly, laser-induced biofilm removal from the glass slides was observed with a high-speed camera (Photron, Fastcam SA -Z) equipped with a 1:1 macro lens (Sigma APO Macro, f = 180 mm, F2.8) providing an optical resolution of 20 μm.…”

“…In narrow geometries such as the apical part of periodontal and peri-implant pockets, cavitation is difficult to induce due to the limited space available for rapid fluid movement and friction with the walls during bubble expansion and contraction. However, our recent results indicate that even in the narrow wedge geometry with an inflamed tissue model, the cavitation energy can be made to propagate through the system and to induce secondary cavitation at the apex of the wedge system, i.e., at a large distance from the site of the primary bubble inception [3] . We have also shown that the viscoelastic properties of an inflamed tissue model have a dramatic effect on the evolution of cavitation.…”

“…Another method that can be considered for the removal of biofilm is photoacoustic cleaning [3] . The two main known mechanisms of cleaning in solutions irradiated with lasers are photoacoustic streaming and cavitation [4] , [5] , which are difficult to separate experimentally.…”

“…In this study, we used a prefabricated narrow wedge system with one of the boundaries made of polydimethylsiloxane (PDMS) to mimic a periodontal or peri-implant pocket. The consistency of polydimethylsiloxane (PDMS) was matched to the consistency of either healthy or severely inflamed periodontal and peri-implant tissues, as determined by a panel of dentists [3] . We studied the effects of the Ultra-Short Pulse (USP) Er:YAG single-pulse modality on the generation of primary and secondary cavitation bubbles within inflamed and healthy tissue models of periodontal and peri-implant pockets, and compared the cleaning efficacy of photoacoustic streaming and cavitation with the effect of classical hydrodynamic streaming.…”