# A Novel, Minimally Invasive Method to Retrieve Failed Dental Implants in Elderly Patients
## 4 Discussion  
This practice-based clinical study discloses the success rate of a novel instrument kit for implant retrieval, with promising use for elderly patients. We found a remarkably high success rate with that kit, which simply acts by the direct application of reverse torque on the implant platform. Few cases needed the elevation of a flap and other surgical procedures, which followed traditional protocols. Complications were rare and could be managed by routine procedures. The successful removal of almost all implants (97%) is likely due to well-distributed shear stresses in the implant-bone junction. For our participants, the counter-torque ratchet system preserved hard and soft tissues, and prevented the relatively large defects produced by the trephine-bur technique. Those advantages favored the immediate placement of a new implant whenever indicated. The study by [PERSON] et al. [16, 17] reported close success rates with a comparable device, i.e., between 86% and 88% of implant removal, with 12-14% of implants removed by trephination. The tested device explains those slightly lower success rates, since it allows a maximum removal torque of 200 Ncm. Applying the same cutoff in this study would impact the observed success rate, since 54% of implants required a higher removal torque. This would be critical for the anterior mandible. Although torque values are significantly higher in that region, it is the preferred place for implant placement in dedentulous patients. Present results imply that counter-torque removal of implants can use higher torques than previously thought. Previous studies recommended avoiding torque values above 120-190 Ncm, which are supposed to increase the risk of bone fracture [18, 19]. Previous implant removal instructions included piezoelectric osteotomy around the coronal third of the implant whenever the torque reached 200 Ncm [20]. Reviewing that cutoff can certainly make removal procedures more conservative, since well-distributed stress may lead to the safe use of high torque values. Since a counter-torque device allows minimal or no bone damage for implant removal, this can be critical for the elderly. Firstly, aging tends to diminish bone quantity and quality, making peri-implant ridge preservation even more important [1]. Moreover, many elderly patients are not good candidates for oral surgery [21], partly due to associated systemic comorbidities and eventual frailty [1, 22]. Minimally invasive approaches (such as counter-torque devices) may enable elective implant removal in cases for which it would be contraindicated otherwise, by reducing postoperative morbidity as well as healing and treatment time. In other words, our results imply that the tested device can be a first choice for the elderly rather than trephination, due to its high success rate and less invasive nature. There is an inherent need to prioritize immediate implant installation following the removal of a failed fixture [16, 23], if the biological and patient-centered aspects favor it. Thus, the device tested in this study would meet this objective and allow the implant installation immediately upon removal. The removal torque values are known to depend on the bone quality [24], implant diameter [12, 25], shape, and surface type [26] among others. As expected, the highest removal torque values were identified in the anterior mandible, due to the highest bone density of this region [27, 28]. Four implants required nearly 450 Ncm for the removal from that region. Despite the development of new implant designs with improvements in their biomechanics [10], the type of connection (internal or external) had no influence on removal torque, even if implant design is expected to influence removal values [20]. Probably both connections were robust enough to transmit stress efficiently with the tested device.