Does the fixture thread depth affect the accuracy of implant placement during fully guided immediate implant placement?: A human cadaver study

Abstract

Background:The fixture thread depth reportedly influences the primary stability of dental implant, but its effect on the positional accuracy in immediate implant placement has not been reported previously. Materials and Methods:Fifty-six single-rooted, anterior and premolar teeth were extracted from six human cadavers, followed by installing either regular-threaded implants (RT group, N = 30) or deep-threaded implants (DT group, N = 26) completely relying on the surgical guide. Optical impressions taken after osteotomy and fixture installation were superimposed with the preoperative virtual planning data to measure the vertical, angular, platform and apex deviations that occurred during osteotomy and installation.Results: While the osteotomy deviations were similar between the two groups, the angular and apex deviation of the DT group (2.67 ± 2.56°; 1.04 ± 0.49 mm, respectively) were significantly larger than those of the RT group (1.61 ± 1.04°; 0.67 ± 0.41 mm, respectively) during installation (p < .05). When the installation deviations were analysed in the anterior and premolar areas separately, the angular, platform and apex deviations of the DT group (3.05 ± 3.26°; 0.75 ± 0.32 mm; 1.08 ± 0.56 mm, respectively) were significantly larger than those of the RT group (1.56 ± 0.73°, 0.59 ± 0.28 mm; 0.62 ± 0.38 mm, respectively) in the anterior site (p < .05), whereas there was no significant intergroup difference in the premolar site. Conclusion:In immediate-implant surgery, using an implant with a deeper thread might increase the deviations during installation, especially in the anterior area.

Effects of a modified surgical protocol on the positional accuracy of dental implants placed using fully guided implant surgery in the partially edentulous posterior ridge with distal extension: a dentiform model study

“…This approach provides clinical advantages in terms of reducing the invasiveness of surgery and enabling accurate placement at the position planned using computer software based on preoperative computed tomography images and intraoral scan data. 1 However, guided surgery does not always guarantee the accuracy, 2 3 especially in the posteriorly extended edentulous area where there are no natural teeth distal to the implant placement site.…”

“…The positional accuracy of each implant placed using the CP or MP was evaluated by comparing the virtually planned position with the actually placed position using superimposed optical scan data based on the previously reported reverse-engineering method. 2 3 11 …”

“…In accordance with the previous research, 2 3 11 the following four parameters were measured to assess the positional accuracy:…”

“… 22 In contrast, recently reported studies have suggested that there is no significant difference in placement accuracy between more experienced and less experienced surgeons, as verified both in vitro 11 and clinically. 3 4 23 However, those data should be interpreted with caution since the included less experienced surgeons were mostly trainees and so were supervised by experts during the procedures. 3 4 23 …”

“… 3 4 23 However, those data should be interpreted with caution since the included less experienced surgeons were mostly trainees and so were supervised by experts during the procedures. 3 4 23 …”