Survival and complication rate of zygomatic implants: a systematic review

Aim :  To evaluate the available literature reporting the survival and complication rate of zygomatic implants, assessing factors (such as surgical technique, surgical/restorative plan, population, study design and characteristics, etc.)  associated with these outcomes. Materials and Methods:  A comprehensive search was performed in three electronic databases, together with a manual search, to identify clinical studies reporting the survival and/or complication rates following zygomatic implant therapy, to quantify relative rates for both stated outcomes.  Results:  101 articles were included: 69 were retrospective in nature, 29 were prospective non-randomized studies and 3 were randomized trials (RCTs). The mean survival rate among retrospective studies was 97.61%, while among prospective non-RCTs and RCTs was 98.53% and 95.92%, respectively. The survival rate was not associated with the surgical technique, nor with the surgical/restorative plan. A trend towards higher survival rate, although not statistically significant (p>0.05), was observed in more recent vs less recent studies. Forty-eight articles reported data on complications related to zygomatic implants, with labial laceration, orbital cavity penetration, hematoma, epistaxis, maxillary sinusitis, infection and oro-antral communication being among the most common adverse event. A lower incidence of maxillary sinusitis was observed for zygomatic implants placed using the extrasinus approach compared to the other surgical approaches (p<0.01). The incidence of maxillary sinusitis and oro-antral communications was found to be less likely in “recent” vs “less recent” studies (p<0.05). Conclusions:  Zygomatic implant therapy is a reliable treatment option for rehabilitating the severely atrophic maxilla, with high implant survival rate and relatively low complication rate. Several factors were found to be associated with the incidence of post-operative complications. Nevertheless, the evidence from the literature is mainly based on non-RCTs and therefore these findings have to be interpreted with cautions.