Dental implant revolutionized oral rehabilitation, becoming the natural teeth replacement by a titanium implant, a successful alternative to treat total or partial edentulism [14, 26, 27]. Nowadays, dental implants are definitely a current procedure in many dental offices [3, 28, 29]. Despite the long-term success shown by different studies [14, 30], implant failure is inevitable [31–33]. Since, to correct early or later failure implants is necessary to remove them, any tool available is necessary. Five different techniques to remove failing implants provided to be successful; however, the counter torque technique, used in our study, is the highest predictability for the insertion of another implant [17, 18, 34–36].

Previous in vivo assessments of bone healing around implants presented histological observations such as bone-implant contact studies under monitored torque values [19, 22, 37]. This study adds an extended methodology of previous investigations, because it provides beyond histological analysis and immunohistochemical analysis to assess peri-implant bone behavior in a real clinical condition.

Histological analysis of early failed implants has indicated that bone overheating might be the most probable cause of failure [33, 37–39]. Bur-forceps, neo bur-elevator-forceps, trephine drill, and scalpel-forceps are safe implant removal techniques, however, require experience and training of the operator. Counter torque technique is an easy and practice tool because it is a heating control procedure; it does not require training and can be performed by a beginner operator, so we opted to test this tool.

The clinical observations of this study showed all 18 implants fixed after 9 months were considered successfully integrated at the time of the removal, and none showed any mobility [40] or signal of infection [21, 33, 41, 42] at sacrifice.

The results of this work showed higher values of removal torque in 9M than in IR specimens. It was expected since the longer healing time (9M) promotes better osseointegration than immediate implant removal. It was verified by the presence of mature bone in the peri-implant bone in the 9M specimens [4, 22, 43].