Table 6 Summary of international studies with evidence level 3
Author | Study type | Patient/implant | Implant location | Prosthesis type | Abutment | F/U period | Outcome | Conclusion |
|---|---|---|---|---|---|---|---|---|
Zembic et al. [3] | Prospective cohort | 18/40 | Canine, premolar, molar | Single crown | Zirconium, titanium | 5.6 years (4.5–6.3) | 1. Prosthesis survival rate: 100% 2. No significant difference in PD, PCR, BOP, and BL | No statistically or clinically significant difference in the 5-year survival rate |
Van Brakel et al. [23] | Case-control study (histological examination) | 22/44 | Mandible (canine region) | No prosthesis | Zirconium, titanium | 3 months | 1. No significant difference in the vascular density of the adjacent tissues 2. No significant difference in the inflammation level | 1. No difference in the soft-tissue health 2. No difference in the biological reactions |
Bressan et al. [38] | Case-control study (The thickness and color of the soft tissue were measured.) | 22/22 | Maxilla anterior | Single crown | Gold, zirconium, titanium (all customized) | Not mentioned | 1. The color of soft tissue around the implant is significantly different from that of the opposite tooth. 2. The titanium abutments showed a significantly greater color difference in soft tissue compared with gold or zirconium abutments. 3. The information on the difference in the soft-tissue thickness and the color difference cannot prove their correlations. | 1. The color of the soft tissue around the implant is different from that of natural teeth regardless of the abutment materials. 2. The titanium abutments show a significantly greater color difference in the soft tissue compared with the gold or zirconium abutments. 3. The thickness of the soft tissue around the implant is not an important element in the effect of the abutment on the soft-tissue color. |
Van Brakel et al. [22] | Case-control study | 22/44 | Mandible (canine region) | No prosthesis | Zirconium, titanium | 3 months | 1. In the two abutments, similar levels of bacteria were detected. 2. No significant difference in the soft-tissue condition around the implant | No difference in the soft-tissue health |
Zembic et al. [7] | Prospective | 18/40 | Canine, premolar, molar | Single crown | Zirconium, titanium | 36 months (31.5–53.3) | 1. No significant difference in PD, PCR, BOP, and BL 2. The two abutments showed biological stability. 3. The degree of gingival discoloration in the two abutments was similar to that of the gingiva of natural teeth. | The zirconium and titanium abutments had the same survival rate and mechanical, biological, and esthetic outcomes during the 3-year follow-up period. |
Sailer et al. [6] | Prospective cohort | 22/40 | Canine, premolar, molar | Single crown | Zirconium, titanium | 12.6 months (± 2.7) | 1. Prosthesis survival rate: 100% 2. No difference in PD, PL, and BOP 3. The colors of the soft tissue around the zirconium and titanium abutments are similar to the gingival color of natural teeth. | During the 1-year follow-up, the survival rates of the zirconium and titanium abutments are the same, and similar esthetic outcomes are shown. |
Glausser et al. [2] | Prospective cohort | 27/54 | Incisor, canine, premolar | Single crown | Zirconium, titanium | 48 months | The survival rate of the abutments: 100% | Zirconium abutments are very stable in supporting the single-tooth implant restoration at the anterior and premolar regions. |