Diederik Hentenaar

14 Chapter 1 (removal of necrotic/granulation tissue) and treat periodontitis if present. Hence, the implant surface should be decontaminated from the adhered biofilm, calculus and/or necrotic bone and the bacterial colonization should be reduced to an extent that is compatible with peri-implant health. Many of the existing therapies used to maintain and treat infected implants have been developed from the treatment of natural teeth. Therapies range from mechanical approaches to chemical agents and light mediated therapy (Ntrouka et al. 2011, Louropoulou 2014, Abrahammi 2019, Jungbauer et al. 2021). Traditionally, mechanical debridement is performed using curettes and/or ultrasonic devices. However, compared to the smooth natural tooth surface the implant surface has areas which are protected, with inaccessible parts to the conventional professional instruments. At the macro-level most implants have threads, which impede with the action of hand scalers and ultrasonic scalers. In other words, although they might touch the outer parts of the threads, difficulty remains in reaching areas between the threads. Moreover, on the microscopic level, crevices on the roughened surfaces can harbor bacteria that defy effective debridement. Hence, the clinical effect of various types of curettes ranging from stainless steel to carbon-fiber and teflon, in the treatment of peri- implant disease, is limited. In general, these studies show a reduction in bleeding on probing in the short term (up to 3-months) but a resolution of disease is rarely achieved. Ultrasonic devices are also proposed for debridement of the implant surface. Modern ultrasonic scalers, which mainly fall into two categories: piezoelectric and magneto- strictive devices, exert a cleaning action which is principally based on vibrational energy. Effective debridement is however limited by how much contact the oscillating tip has with the surface area to shatter surface deposits. In addition, ultrasonic scalers are also able to create cavitation, which is characterized by formation and rapid collapse of gas or vapour bubbles in a fluid (Brennen 1995, Vyas et al. 2020). The forces generated from cavitation bubbles and acoustic streaming (fluid flow) are thought to remove the bacterial biofilm. While traditional (metal) ultrasonic tips are available, dedicated ultrasonic tips made of implant compatible materials (i.e., carbon fiber, silicone or poly ether ether ketone (PEEK) /plastic) have been proposed to treat the implant surface to minimize scratches on the implant surfaces. Ultrasonic therapy seems able to reduce clinical signs of inflammation to a greater extent than carbon fiber/titanium curettes in the non-surgical treatment of peri-implantitis (Karring et al. 2005; Renvert et al. 2009). However, resolution of disease has not been reported following the use of ultrasonic therapy.