Table 3 Results of risk of bias assessment by AMSTAR tool
Author (year), country of origin, funding(Y/N/?)-Conflict of interest(Y/N/?) [JCR] | Research question or objectives | Primary outcome(s) | Number and designs of included studies (number of patients and implants) | Control group | SR/SR and M | Databases searched (search date) | Follow-up | Quality assessment tools | Implant loading (immediate/late) | Type of edentulism (total/partial) | Main findings | Main conclusion |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Wang et al. (2015) [49], China and Spain, (Y-N) [Q1; 1,96] | To assess the predictability of oral rehabilitation by four zygomatic implants with no anterior support in regard to implant survival, technical and biologic complications | The survival rate of the zygomatic implants | 3 human clinical trials (2 prospective and 1 retrospective) (49 patients, 196 ZIs) | None | SR and M | (from September 2000 to November 2013) | 30–363 (mo) | None | Immediate loading | Fully edentulous | - Zygomatic implant survival rate weighted mean (WM) was 96.7% (range, 95.8 to 99.9%), with a 95% confidence interval (CI) of 92.5 to 98.5%. - Limited number of surgical complications and prosthetic complications | Maxillary rehabilitation by four zygomatic implants with no anterior support is a reliable approach |
Tuminelli et al. (2017) [44], USA, (NR-NR) [2.39] | To systematically review the outcome of immediate loaded zygomatic implants | Immediate load survival, complications | 38 articles | None | SR | PubMed (from 1990 until June 2016) | At least 12 months follow-up (according to text follow-ups ranged between 1 and 10 (y)) | None | Immediate loading | Both totally or partially edentulous maxilla | - The success of implants and prostheses ranged from 96 to 100%. - The complication rates are relatively few, rarely catastrophic, and easily managed | Immediately loading zygomatic implants for the restoration of the severely atrophic maxilla presents a viable alternative for treatment of the atrophic maxilla and is recommended for the restoration of the severely atrophic maxilla with or without anterior conventional implants |
Molinero-Mourel et al. (2016) [47], Spain, (NR-N) [1.07] | To analyze and describe the most frequent surgical complications associated with the use of zygomatic implants | Complications | 13 articles (1 SR, 5 pros, 5 retros, 1 pros and retros, 1 cohort) (3240 ZIs) | None | SR | PubMed (up to December 2015) | 1–12 (y) | None | All studies were immediate loading | Both totally or partially edentulous maxilla | - Out of the most frequent surgical complications, sinusitis (3.9%) and failure in osseointegration (2.44%) are highlighted | Rehabilitation using zygomatic implants is a consolidated therapeutic option although it does not lack in possible complications; therefore, it should be reserved only to professional clinicians with vast surgical experience |
Goiato et al. (2014) [46], Brazil (N-N) [1.52] | To evaluate clinical studies on the follow-up survival of implants inserted in the zygomatic bone for maxillary rehabilitation. | Survival of implants | 25 articles (design NR) (748 ZIs) | None | SR | PubMed/MEDLINE, Embase, and Cochrane Library databases (from 2000 to July 2012) | Mean follow-up: 42.2 (mo) (range 0–144) | None | Fifteen studies conducted late loading (prosthesis insertion at 4–6 months after initial implant loading), whereas 10 studies reported immediate loading | Both totally or partially edentulous maxilla | - These studies reported the insertion of a total of 1541 zygomatic implants and 33 implant failures -After a 36-month follow-up, the survival rate was 97.86% | - The survival of osseointegrated implants may also be related to the use of suitable presurgical examinations and the parameters used during the surgical procedures - Zygomatic implants appear to be an effective alternative for the treatment of an atrophic maxilla. |
Chrcanovic et al. (2013) [45], Sweden (NR,N) [1.66] | “What is the survival rate of zygomatic implants (ZIs)?” and “What are the most common complications related to surgery of zygomatic implants?” | Survival rate, complication | 42 article, 1145 patients and 2402 ZIs | None | SR | PubMed (Up to March 2012) | Range: 6–120 (mo) | None | Between 42 studies, 12 evaluated the use of ZIs applied with immediate function protocols | Both totally or partially edentulous maxilla | - 12 evaluated the use of ZIs applied immediate protocol and 3 after maxillary resections for tumor ablations (showed lower success.). - Of 2402 ZIs, 56 ZIs were reported as failures - The CSR over a 12-year period was 96.7%. | - ZI placement needs very experienced surgeons since delicate anatomic structures such as the orbita and brain may be involved - Despite the high survival rate observed, there is an impending need for further investigations |
Chrcanovic et al. (2016) [15], Sweden (NR-N) [1.66] | To assess the survival rate of zygomatic implants (ZIs) and the prevalence of complications based on previously published studies | Complications | Sixty-eight studies were included one randomized clinical trial,16 prospective studies, and 51 retrospective analyses, comprising 4556 ZIs in 2161 | Conventional implants | SR | PubMed/Medline, Web of Science, and the Cochrane Oral Health Group Trials Register (up to December 2015) | Range: 1–144 (mo) | None | 26 studies immediate loading and studies 34 studies evaluating delayed loading protocols | Both totally or partially edentulous maxilla | Immediate loading showed a statistically lower ZI failure rate than other studies (P = .003). - Studies evaluating ZIs for the rehabilitation of patients after maxillary resections presented lower survival rates. - Postoperative complications: sinusitis, 2.4% soft tissue infection, 2.0%, paresthesia, 1.0% and oroantral fistulas, 0.4% | - ZIs present a high 12-year CSR, with most failures occurring at the early stages postoperatively. - Main complication was sinusitis, which can appear several years after placement |
Aboul-Hosn Centenero et al. (2018) [48], Spain (Y-N) [1.15] | To compare the survival rates (SRs) of oral rehabilitations performed with 2 zygomatic implants (ZIs) combined with regular implants (RIs) versus 4 ZIs | Survival rates | 6 articles (4 prospective and 2 retrospective case series) A total of 130 ZIs and 186 conventional implants were placed in 64 patients. | 4 ZIs (case) versus2 ZIs combined with regular implants RIs (control) | SR and M | MEDLINE/PubMed, Cochrane Central register of Controlled trials Cochrane Oral Health group Trials Register, and EMBASE between 2007, and June 30, 2015 | Range: 12–82 (mo) | The criteria were modified according to the PRISMA 2009 checklist statement [17] | Immediate loading | Fully edentulous | - ZIs SR weighted mean was 98.0%, CI [96.7 to 99.8%]. For the control group (2 ZIs + 2 RIs) and the test group (4 ZIs), the implant SR was 98.6% and 97.4%, respectively - No statistically significant differences in terms of SRs were obtained between both groups, P = 0.286. | - No statistical differences in 2 groups in terms of survival and failure rates. The reduction on treatment time and morbidity related to regenerative approaches may be its main advantage. - The zygoma quad seems to be the treatment of choice for the severely atrophic maxilla. |