Table 1. General characteristics of the included studies.
| Authors and year | Type of study | Follow-up period | Biological complications with no implant removal (%) | Implants failed and removed (survival rate) | No. of patients/total implants/SST |
|---|---|---|---|---|---|
| Bäumer et al., 2017 [9] | Retrospective case series | 51 months | No complications | 0 (100%) | 10/10/10 |
| Gluckman et al., 2017 [10] | Retrospective study | 1 year | 16 exposures, 3 infections, 1 migration (19.5%) | 5 (96.1%) | 128/128/128 |
| Siormpas et al., 2018 [11] | Retrospective study | 17 months (max 120 months of follow-up) | No complications (3 at 120 months of follow-up)a) | 3 (1.2%) (5 at 120 months of follow-up)b) | 182/250/250 |
| Mitsias et al., 2020 [12] | Retrospective cohort study | 3 years | No complications | 0 (100%) | 10/13/13 |
| Siormpas et al., 2014 [18] | Retrospective case series | 2 years | 1 periapical granulomatous defect (2.17%) | 0 (100%) | 46/46/46 |
| Abadzhiev et al., 2014 [19] | Retrospective case series | 2 years | No complications | 0 (100%) | 25/26/10 |
| Hana and Omar, 2020 [21] | Retrospective study | 12 months | 2 internal and other external shield exposures (20%) | 1 (95%) | 40/40/20 |
| Bramanti et al., 2018 [22] | Randomized controlled trial | 3 years | No complications | 0 (100%) | 40/40/20 |
| Sun et al., 2020 [23] | Randomized clinical study | 2 years | No complications | 0 (100%) | 30/30/15 |
| Tiwari et al., 2019 [24] | Randomized clinical study | 1 year | 1 apical resorption of the shield (12%) | 0 (100%) | 16/16/8 |
| Barakat et al., 2017 [25] | Randomized controlled clinical trial | 7 months | No complications | 0 (100%) | 20/20/10 |
| Atef et al., 2020 [26] | Randomized clinical study | 12 months | 0 | 0 (100%) | 42/42/21 |
| Abd-Elrahman et al., 2020 [27] | Randomized clinical study | 6 months | 1 internal shield exposure (10%) | 0 (100%) | 40/40/20 |
| Santhanakrishnan et al., 2021 [28] | Randomized clinical study | 6 months | 0 | 0 (100%) | 75/75/25 |
| Troiano et al., 2014 [29] | Prospective case study | 6 months | No complications | 0 (100%) | 7/10/10 |
| Han et al., 2018 [30] | Prospective study | 1 year | No complications | 0 (100%) | 30/40/40 |
| Fattouh, 2018 [31] | Prospective study | 12 months | 0 | 0 (100%) | 20/20/10 |
SST: socket-shield technique.
a)Root fragment infection and peri-implant mucositis at 113 months (n=1) and root fragment infections with fistula mucositis at 51 months and 83 months of follow-up (n=2), respectively. b)Failures of osseointegration.at 3 months (n=2) and peri-implantitis at 12, 36, and 59 months (n=3), respectively.