Long-term survival and complications of Quad Zygoma Protocol with Anatomy-Guided Approach in severely atrophic maxilla: A retrospective follow-up analysis of up to 17 years.

INTRODUCTION: The objective of the study was to provide long-term clinical outcomes and complications in the severely atrophic edentulous maxillae treated by means of the quad zygoma protocol (QZP) using the Anatomy-Guided Approach (AGA). METHODS: This was a retrospective cohort study of all consecutive patients with severely atrophic edentulous maxilla and insufficient bone height and width in the anterior and posterior regions bilaterally, who underwent rehabilitation with the QZP between May 2006 and December 2021. All patients were followed for at least 1 year. All zygomatic implants (ZIs) were placed by the same surgeon. The primary endpoint of the study was the implant survival rate. Secondary endpoints were implant success rate, prosthesis success rate, complications, and Oral Health-Related Quality of Life using the OHIP-14 questionnaire. RESULTS: A total of 56 patients (men 16, women 40) with 224 ZIs (Nobel Biocare, n = 204; Straumann, n = 16; Southern Implant, n = 4) placement were included with a mean follow-up period 8.8 ± 3.9 years (range, 1.2-17.0). The survival (success) rate was 97.7%. Five ZIs in four patients failed. The mean time between implant placement and failure was 8.6 years (range, 0.5-13.3). All patients received immediate loading with acrylic prosthesis. The successful rates for the definitive prosthesis were 98.2%. Forty-two patients received posterior cantilever for rehabilitation of fixed definitive prosthesis. Local orofacial inflammation (35.7%) and Sinusitis (12.5%) were the most common complications, occurring at a mean follow-up of 10.0 (range, 4.2-14.9) and 10.3 (range, 4.3-16.2) years, respectively. In 48 patients, the mean score of the OHIP-14 questionnaire was 1.7 ± 2.6 with the follow-up period of 9.0 ± 4.1 years. CONCLUSIONS: The rehabilitation of severely atrophic edentulous maxilla using the QZP has shown a predictable and high survival rate in the long term. The implementation of an immediate loading protocol offers potential benefits in stabilizing ZIs with cross-arch stabilization. Moreover, the use of a posterior cantilever in reconstruction can effectively establish functional occlusion through well-distributed ZIs, eliminating the need for additional implant placement.

ITI consensus report on zygomatic implants: indications, evaluation of surgical techniques and long-term treatment outcomes.

OBJECTIVES: The aim of the ITI Consensus Workshop on zygomatic implants was to provide Consensus Statements and Clinical Recommendations for the use of zygomatic implants. MATERIALS AND METHODS: Three systematic reviews and one narrative review were written to address focused questions on (1) the indications for the use of zygomatic implants; (2) the survival rates and complications associated with surgery in zygomatic implant placement; (3) long-term survival rates of zygomatic implants and (4) the biomechanical principles involved when zygoma implants are placed under functional loads. Based on the reviews, three working groups then developed Consensus Statements and Clinical Recommendations. These were discussed in a plenary and finalized in Delphi rounds. RESULTS: A total of 21 Consensus Statements were developed from the systematic reviews. Additionally, the group developed 17 Clinical Recommendations based on the Consensus Statements and the combined expertise of the participants. CONCLUSIONS: Zygomatic implants are mainly indicated in cases with maxillary bone atrophy or deficiency. Long-term mean zygomatic implant survival was 96.2% [95% CI 93.8; 97.7] over a mean follow-up of 75.4 months (6.3 years) with a follow-up range of 36-141.6 months (3-11.8 years). Immediate loading showed a statistically significant increase in survival over delayed loading. Sinusitis presented with a total prevalence of 14.2% [95% CI 8.8; 22.0] over a mean 65.4 months follow-up, representing the most common complication which may lead to zygomatic implant loss. The international experts suggested clinical recommendations regarding planning, surgery, restoration, outcomes, and the patient's perspective.

The Accuracy of Zygomatic Implant Placement Assisted by Dynamic Computer-Aided Surgery: A Systematic Review and Meta-Analysis.

PURPOSE: The present systematic review aimed to investigate the accuracy of zygomatic implant (ZI) placement using dynamic computer-aided surgery (d-CAIS), static computer-aided surgery (s-CAIS), and a free-hand approach in patients with severe atrophic edentulous maxilla and/or deficient maxilla. METHODS: Electronic and manual literature searches until May 2023 were performed in the PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases. Clinical trials and cadaver studies were selected. The primary outcome was planned/placed deviation. Secondary outcomes were to evaluate the survival of ZI and surgical complications. Random-effects meta-analyses were conducted and meta-regression was utilized to compare fiducial registration amounts for d-CAIS and the different designs of s-CAIS. RESULTS: A total of 14 studies with 511 ZIs were included (Nobel Biocare: 274, Southern Implant: 42, SIN Implant: 16, non-mentioned: 179). The pooled mean ZI deviations from the d-CAIS group were 1.81 mm (95% CI: 1.34-2.29) at the entry point and 2.95 mm (95% CI: 1.66-4.24) at the apex point, and angular deviations were 3.49 degrees (95% CI: 2.04-4.93). The pooled mean ZI deviations from the s-CAIS group were 1.19 mm (95% CI: 0.83-1.54) at the entry point and 1.80 mm (95% CI: 1.10-2.50) at the apex point, and angular deviations were 2.15 degrees (95% CI: 1.43-2.88). The pooled mean ZI deviations from the free-hand group were 2.04 mm (95% CI: 1.69-2.39) at the entry point and 3.23 mm (95% CI: 2.34-4.12) at the apex point, and angular deviations were 4.92 degrees (95% CI: 3.86-5.98). There was strong evidence of differences in the average entry, apex, and angular deviation between the navigation, surgical guide, and free-hand groups (p < 0.01). A significant inverse correlation was observed between the number of fiducial screws and the planned/placed deviation regarding entry, apex, and angular measurements. CONCLUSION: Using d-CAIS and modified s-CAIS for ZI surgery has shown clinically acceptable outcomes regarding average entry, apex, and angular deviations. The maximal deviation values were predominantly observed in the conventional s-CAIS. Surgeons should be mindful of potential deviations and complications regardless of the decision making in different guide approaches.

Evaluation of surgical techniques in survival rate and complications of zygomatic implants for the rehabilitation of the atrophic edentulous maxilla: a systematic review.

PURPOSE: To assess the outcome [zygomatic implant (ZI) survival] and complications of the original surgical technique (OST) and an Anatomy-Guided approach (AGA) in the placement of ZI in patients with severely atrophic maxillae. METHODS: Two independent reviewers conducted an electronic literature search from January 2000 to August 2022. The inclusion criteria were articles reporting at least five patients with severely atrophic edentulous maxilla undergoing placement OST and/or AGA, with a minimum of 6 months of follow-up. Number of patients, defect characteristics, number of ZI, implant details, surgical technique, survival rate, loading protocol, prosthetic rehabilitation, complications, and follow-up period were compared. RESULTS: Twenty-four studies comprised 2194 ZI in 918 patients with 41 failures. The ZI survival rate was 90.3-100% in OST and 90.4-100% in AGA. Probability of complications with ZI with OST was as follows: sinusitis, 9.53%; soft tissue infection, 7.50%; paresthesia, 10.78%; oroantral fistulas, 4.58%; and direct surgical complication, 6.91%. With AGA, the presenting complications were as follows: sinusitis, 4.39%; soft tissue infection, 4.35%; paresthesia, 0.55%; oroantral fistulas, 1.71%; and direct surgical complication, 1.60%. The prevalence of immediate loading protocol was 22.3% in OST and 89.6% in the AGA. Due to the heterogeneity of studies, statistical comparison was only possible after the descriptive analysis. CONCLUSIONS: Based on the current systematic review, placing ZI in severely atrophic edentulous maxillae rehabilitation with the OST and AGA is associated with a high implant survival rate and surgical complications within a minimum of 6 months follow-up. Complications, including sinusitis and soft tissue infection around the implant, are the most common. The utilization of immediate loading protocol is more observed in AGA than in OST.

Round and flat zygomatic implants: effectiveness after a 1-year follow-up non-interventional study.

INTRODUCTION: There are few zygomatic implants (ZI) designs available. The objective of this non-interventional study was to report the effectiveness of two new site-specific ZI, selected and placed following the zygoma anatomy-guided approach (ZAGA). MATERIALS AND METHODS: Consecutive patients presenting indications for rehabilitation using ZI were treated according to ZAGA Concept recommendations. Implants were immediately loaded following the manufacturer's instructions. Success criteria regarding prosthetic offset, rhino-sinus status, soft tissue condition, and implant stability were additionally used as outcome parameters. RESULTS: Twenty patients were followed for a period of 12 to 28 months (average 18.8 months). Ten received 2 ZI plus regular anterior implants; One received 3 ZI plus regular implants and nine received 4 ZI. In total, 59 ZI were placed, 34 (58%) Straumann ZAGA-Flat design, and 25 (42%) ZAGA-Round. Forty-nine percent of the sites were classified as ZAGA-4 type and 27% as ZAGA-2. Four patients (20%) presented discontinuities of the sinus-nose floor before surgery and 15 patients (75%) presented previous sinus opacities. All implants bar one reached more than 45 N.cm of insertion torque. No surgical complications were observed. After 1 year, the modified Lund-Mackay score was negative in 17 patients. Seventeen sites in 11 patients exhibited decreased opacity when pre-surgical imaging was compared to 1-year post-surgical CBCT. All implants and prostheses remained stable and in function. CONCLUSIONS: The study concluded 100% implant/prosthesis survival rates and low complication levels. Within the limitations of the sample and observation period, results suggest that even in cases of extremely resorbed maxillae (as per cases in this study), ZAGA-Flat and ZAGA-Round ZI are viable treatment options when restoring atrophic maxillae following the ZAGA protocol.

Identification of the Pathway and Appropriate Use of Four Zygomatic Implants in the Atrophic Maxilla: A Cross-Sectional Study.

PURPOSE: This cross-sectional study aimed to identify and characterize the pathway for appropriate placement of four zygomatic implants in the severely atrophic maxilla and to group the anatomical variations of the osteotomy trajectory for anterior zygomatic implants. MATERIALS AND METHODS: CBCT images of patients presenting indications for the use of four zygomatic implants to withstand a maxillary rehabilitation were reviewed. Cross-sectional planes corresponding to the implant trajectories, designed according to a zygoma anatomy-guided approach for implants placed in the anterior and posterior maxilla, were assessed separately. The relationship of the implant osteotomy trajectory with the correlated residual alveolar bone, nasal and sinus cavities, maxillary wall, and zygomatic bone anatomies was established. RESULTS: The study population included 122 globally recruited patients, with 488 zygomatic implants, 244 of which had their starting point on the anterior incisor-canine area and 244 on the posterior premolar-molar area. The anatomy of the osteotomy path designed for the anterior implants ("A") was named and grouped into five assemblies from zygomatic anatomy-guided ZAGA A-0 to A-4, representing 2.9%, 4.5%, 19.7%, 55.7%, and 17.2% of the studied sites. Percentages for posterior implant ("P") trajectories of the osteotomy were grouped and named as ZAGA P-0 to P-4, representing 5.7%, 10.2%, 8.2%, 18.4%, and 57.4% of the sites, respectively. Approximately 70% of the population presented anatomical intra-individual differences. CONCLUSION: The trajectory of the zygomatic implant followed different anatomical pathways depending on its coronal point being anteriorly or posteriorly located, which justifies a new zygoma anatomy-guided approach classification for anteriorly placed zygomatic implants. Topographic characteristics of the anatomical structures that are cut by an anterior oblique plane joining the lateral incisor-canine area to the zygomatic bone, representing the planned anterior osteotomy path in a quadruple-zygoma indication, have not been previously reported. Adaptation of surgical procedures and implant sections/designs to individual patients' anatomical characteristics is essential to reduce early and long-term complications.

Quad Zygomatic Implants: A Systematic Review and Meta-analysis on Survival and Complications.

PURPOSE: To assess the postoperative complications and outcome (implant survival) of quad zygomatic implants inserted in patients with edentulism and severely atrophic maxillae. MATERIALS AND METHODS: Two independent reviewers conducted an electronic search of the literature (PubMed, Scopus, EBSCO, Web of Science) from January 2000 to February 2019. The inclusion criteria were articles published in English reporting data of at least five patients with severely atrophic edentulous maxillae undergoing placement of four zygomatic implants without additional insertion of standard implants, with a minimum of 6 months of follow-up. Data extracted included number of patients, characteristics of the maxillary defect, number of zygomatic implants, implant details, surgical procedure, prosthetic rehabilitation, postoperative complications, survival rate, and length of follow-up after definitive prosthesis delivery. RESULTS: Eleven studies with 166 patients were included. The heterogeneity among studies was not significant. The pooled incidence rates of complications were as follows: sinusitis 12% (95% confidence interval [CI]: 4% to 23%), malposition and surgical guiding failure 11% (95% CI: 3% to 21%), local infection/injury 10% (95% CI: 3% to 18%), and prosthetic complications 5% (95% CI: 0% to 13%). The implant survival rate ranged between 95.8% and 100%, and the pooled implant survival rate in the meta-analysis was 98% (95% CI: 97% to 99%). CONCLUSION: Quad zygomatic implants inserted in patients with severely atrophic edentulous maxillae have a high implant survival rate, but the incidence of complications should not be underestimated.

Clinical Performance of Zygomatic Implants-Retrospective Multicenter Study.

The main objective of this analysis was to evaluate (1) implant survival, (2) biologic complications, and (3) demographics associated with zygomatic implants placed according to the zygomatic anatomy-guided approach (ZAGA). This retrospective multicenter study reviewed data from the charts of 82 consecutive patients who had received 182 zygomatic implants. Patients were fully edentulous (62.2%), partially edentulous (22.0%), or had failing dentition (15.9%). Most patients (87.5%) did not have previous sinusitis and 11.3% had been previously treated for it. Additionally, about half of the patients (53.8%) did not present periodontal pathology, and one-third (36.3%) did, but were subsequently treated. Most implants (93.8%) were loaded immediately, i.e., within 48 h of placement. Implants were followed for 10.5 ± 7.2 months, and all were recorded as surviving and stable at last follow-up. Post-operative complications were infrequent and included sinusitis (10.1%) and peri-implant hyperplasia (0.8%). The low complication rate and 100% implant survival and stability indicate that zygomatic implants offer a viable treatment option when performing graftless restoration of severely resorbed maxilla, including immediate loading protocols.

A Prospective Single-Cohort Multicenter Study of an Innovative Prefabricated Three-Implant-Supported Full-Arch Prosthesis for Treatment of Edentulous Mandible: 1-year Report.

PURPOSE: To clinically evaluate a recently developed, standardized, three-implant-supported full-arch treatment concept for fully edentulous mandibles. MATERIALS AND METHODS: This ongoing multinational prospective cohort study is evaluating the performance of the treatment concept over 5 years in patients who were fully edentulous or had failing dentition of the mandible. The primary outcome was the cumulative survival rate of implants (CSRI). Secondary outcomes included the cumulative survival rate of the prostheses (CSRP), marginal bone level change, soft tissue outcomes, impact on quality of life, and patient and clinician satisfaction. The 1-year report is presented here. RESULTS: In total, 110 patients (330 implants) were included. Prostheses underwent immediate loading in 76.4% of cases and early loading in 23.6% of cases. The mean surgical time was 1.60 ± 0.78 hours, and the mean laboratory time was 3.99 ± 1.74 hours. At 1 year, eight implants and three prostheses failed, yielding an implant-level CSRI of 97.5% and a CSRP of 97.3%. All prosthetic failures were due to loss of two implants in the patient. The mean marginal bone level change at 1 year was -0.62 ± 1.39 mm. Among soft tissue outcomes, the Bleeding Index improved significantly between the 6-month and 1-year follow-up, and 242 implants (75%) were surrounded by keratinized mucosa by the 6-month follow-up. Patients reported a significant improvement in quality of life between prosthesis placement and the 6-month follow-up based on the Oral Health Impact Profile for Edentulous 21 questionnaire. Both patient and clinician satisfaction with function and esthetics were high throughout treatment. CONCLUSION: This novel treatment concept using a passively fitting standardized framework with simplified surgical and prosthetic workflow demonstrated high survival and excellent outcomes at 1 year while reducing chair and fabrication time. This concept may offer patients a safe and efficient option for full-arch mandibular prostheses.

Quad Zygoma: Technique and Realities.

Four zygomatic implants may be used in patients with severe maxillary atrophy for rehabilitation with a fixed or removable prosthesis. Immediate loading is also typically performed, providing patients with a less invasive and more efficient solution for rehabilitation. Options for immediate loading are presented. The indications, contraindications, procedure, and complications are reviewed. Appropriate treatment planning and work-up are highlighted, as they are required for success in conjunction with advanced surgical skill. Scientific evidence, although lacking in quantity, suggests that the quad zygoma approach offers a predictable solution for the challenge of severe maxillary atrophy; high implant survival rates are noted.

Immediately loaded zygomatic implants vs conventional dental implants in augmented atrophic maxillae: 1-year post-loading results from a multicentre randomised controlled trial.

PURPOSE: To compare the clinical outcome of immediately loaded cross-arch maxillary prostheses supported by zygomatic implants vs conventional implants placed in augmented bone. MATERIALS AND METHODS: In total, 71 edentulous patients with severely atrophic maxillas without sufficient bone volumes for placing dental implants, or when it was possible to place only two implants in the anterior area (minimal diameter 3.5 mm and length of 8 mm) and less than 4 mm of bone height subantrally, were randomised according to a parallel group design to receive zygomatic implants (35 patients) to be loaded immediately vs grafting with a xenograft, followed after 6 months of graft consolidation by placement of six to eight conventional dental implants submerged for 4 months (36 patients). For immediate loading, zygomatic implants had to be inserted with an insertion torque superior to 40 Ncm. Screw-retained metal reinforced acrylic provisional prostheses were provided, to be replaced by definitive Procera Implant Bridge Titanium prostheses (Nobel Biocare, Göteborg, Sweden), with ceramic or acrylic veneer materials 4 months after initial loading. Outcome measures were: prosthesis, implant and augmentation failures, any complications, quality of life (OHIP-14), patients' number of days with total or partial impaired activity, time to function and number of dental visits, assessed by independent assessors. Patients were followed up to 1 year after loading. RESULTS: No augmentation procedure failed. Five patients dropped out from the augmentation group. Six prostheses could not be delivered or failed in the augmentation group vs one prosthesis in the zygomatic group, the difference being statistically significant (difference in proportions = -16.5%; P = 0.045; 95% CI: -0.34 to -0.01). Eight patients lost 35 implants in the augmentation group vs two patients who lost four zygomatic implants, the difference being statistically significant (difference in proportions = -20.1%; P = 0.037; 95% CI: -0.38 to -0.02). A total of 14 augmented patients were affected by 22 complications, vs 28 zygomatic patients (40 complications), the difference being statistically significant (difference in proportions = 34.8%; P = 0.005; 95% CI: 0.12 to 0.54). The 1-year OHIP-14 score was 3.93 ± 5.86 for augmented patients and 3.97 ± 4.32 for zygomatic patients with no statistically significant differences between groups (mean difference = 0.04; 95% CI: -2.56 to 2.65; P = 0.747). Both groups had significantly improved OHIP-14 scores from before rehabilitation (P < 0.001 for both augmented and zygomatic patients). On average, the number of days of total infirmity was 7.42 ± 3.17 for the augmented group and 7.17 ± 1.96 for the zygomatic group, the difference not being statistically significant (mean difference = -0.25; 95% CI: -1.52 to 1.02; P = 0.692). The number of days of partial infirmity were on average 14.24 ± 4.64 for the augmented group and 12.17 ± 3.82 for the zygomatic group, the difference being statistically significant (mean difference = -2.07; 95% CI: -4.12 to -0.02; P = 0.048). The mean number of days that needed to have a functional prosthesis was 444.32 ± 207.86 for augmented patients and 1.34 ± 2.27 for zygomatic patients, the difference being statistically significant (mean difference = -442.98; 95% CI: -513.10 to -372.86; P < 0.001). The average number of dental visits was 19.72 ± 12.22 for augmented patients and 15.12 ± 5.76 for zygomatic patients, the difference not being statistically significant (mean difference = -4.61; 95% CI: -9.31 to 0.92; P = 0.055). CONCLUSIONS: Preliminary 1-year post-loading data suggest that immediately loaded zygomatic implants were associated with statistically significantly fewer prosthetic failures (one vs six patients), implant failures (two vs eight patients) and time needed to functional loading (1.3 days vs 444.3 days) when compared to augmentation procedures and conventionally loaded dental implants. Even if more complications were reported for zygomatic implants, they proved to be a better rehabilitation modality for severely atrophic maxillae. Long-term data are absolutely needed to confirm or dispute these preliminary results.

Immediately loaded zygomatic implants vs conventional dental implants in augmented atrophic maxillae: 4 months post-loading results from a multicentre randomised controlled trial.

PURPOSE: To compare the clinical outcome of immediately loaded cross-arch maxillary prostheses supported by zygomatic implants vs conventional implants placed in augmented bone. MATERIALS AND METHODS: A total of 71 edentulous patients with severely atrophic maxillas, who did not have sufficient bone volume to place dental implants or when it was possible to place only two implants in the front area (minimal diameter 3.5 mm and length of 8 mm) and less than 4.0 mm of bone height subantrally, were randomised according to a parallel group design. They (35 patients) received zygomatic implants to be loaded immediately vs grafting with a xenograft, followed, after 6 months of graft consolidation, by the placement of six to eight conventional dental implants, submerged for 4 months (36 patients). To be loaded immediately, zygomatic implants had to be inserted with an insertion torque superior to 40 Ncm. Screw-retained, metal-reinforced, acrylic provisional prostheses were provided to be replaced by definitive Procera Implant Bridge Titanium prostheses (Nobel Biocare, Göteborg, Sweden) with ceramic or acrylic veneer materials 4 months after initial loading. Outcome measures were: prosthesis, implant and augmentation failures, any complications, quality of life (OHIP-14), the number of days that patients experienced total or partial impaired activity, time to function, and number of dental visits, assessed by independent assessors. Patients were followed up to 4 months after loading. RESULTS: No augmentation procedure failed. Three patients dropped out from the augmentation group. Six prostheses could not be delivered or failed in the augmentation group vs one prosthesis in the zygomatic group, the difference being statistically significant (difference in proportions = 15.32%; P = 0.04; 95% CI: 0.23 to 31.7). Eight patients lost 35 implants in the augmentation group vs three implants in one patient from the zygomatic group, the difference being statistically significant (difference in proportions = 21.38%; P = 0.001; 95% CI: 3.53 to 39.61). In total, 14 augmented patients were affected by 20 complications vs 26 zygomatic patients (35 complications), the difference being statistically significant (difference in proportions = 31.87%; P = 0.008; 95% CI: 6.48 to 53.37). The OHIP-14 score was 3.68 ± 5.41 for augmented patients and 4.97 ± 5.79 for zygomatic patients, with no statistically significant differences between groups (mean difference = 1.29; 95%CI -1.60 to 4.18; P = 0.439). Both groups had significantly improved OHIP-14 scores from before rehabilitation (P < 0.001 for both augmented and zygomatic patients). The number of days of total infirmity was, on average, 7.42 ± 3.17 for the augmented group and 7.17 ± 1.96 for the zygomatic group, the difference not being statistically significant (mean difference = -0.25; 95% CI: -1.52 to 1.02; P = 0.692). Days of partial infirmity were on average 14.24 ± 4.64 for the augmented group and 12.17 ± 3.82 for the zygomatic group, the difference being statistically significant (mean difference = -2.07; 95% CI: -4.12 to -0.02; P = 0.048). The mean number of days to have a functional prosthesis was 444.32 ± 207.86 for augmented patients and 1.34 ± 2.27 for zygomatic patients, the difference being statistically significant (mean difference = -442.9; 95% CI: -513.10 to -372.86; P < 0.001). The average number of dental visits was 16.79 ± 10.88 for augmented patients and 12.58 ± 5.21 for zygomatic patients, the difference not being statistically significant (mean difference = -4.21; 95% CI -8.48 to 0.06; P = 0.053). CONCLUSIONS: Preliminary 4-months post-loading data suggest zygomatic implants were associated with statistically significantly less prosthetic (one vs six patients) and implant failures (one patient lost three implants versus 35 implants in eight patients) as well as time needed to functional loading (1.3 days vs 444.3 days) when compared with augmentation procedures and conventionally loaded dental implants. Even if more complications were reported for zygomatic implants, which were solved spontaneously or could be handled, zygomatic implants proved to be a better rehabilitation modality for severely atrophic maxillae. Long-term data are essential to confirm or dispute these preliminary results. Conflict of interest statement: This study was originally supported by Nobel Biocare, the manufacturer of the implants, and the provisional and definitive prosthetic components used in this study, which were provided free for the patients. However, before any results were known, Nobel Biocare withdrew the financial support and recruitment had to be stopped. Tecnoss (Giaveno, Torino, Italy) kindly donated the bone substitutes and the membranes, whereas Global D (Brignais, France) donated the osteosynthesis screws. Data property belonged to the authors and by no means did the manufacturers interfere with the publication of the results.

5-year outcome of cross-arch prostheses supported by four immediately loaded zygomatic implants: A prospective case series.

PURPOSE: To evaluate the clinical outcome of maxillary prostheses supported by four immediately loaded zygomatic implants in the rehabilitation of edentulous patients with severe atrophic maxillae after 5 years of function. MATERIALS AND METHODS: Out of a total of 17 consecutive patients with severe atrophy in the maxillae (Cawood and Howell classification C-VI and D-V or D-VI) and whom were rehabilitated using four immediately loaded zygomatic implants, three were lost during follow-up. Outcome measures were success rates of the prostheses, success rates of the zygomatic implants, complications and oral health-related quality of life (OHIP-14 questionnaire). RESULTS: In 14 patients assessed at 5 years after operation, no prosthesis or zygomatic implants failed, although one implant placed in an unfavourable position was not used. Fifty percent of the patients had complications, which included penetration of the orbital cavity during the drilling procedure (1 patient), infection followed by a fistula at one zygomatic implant (1 patient), sinusitis (2 patients), fracture of the abutment screw (1 patient) and fracture of the prostheses (2 patients). All complications were resolved without clinical consequences. At 5 years the mean score of the OHIP-14 was 3.8, which is similar to that of the general population. CONCLUSION: Results at 5 years indicate that the use of four immediately loaded zygomatic implants is a reliable approach for successful rehabilitation of edentulous patients with severely atrophied maxillae.

Reliability of four zygomatic implant-supported prostheses for the rehabilitation of the atrophic maxilla: a systematic review.

PURPOSE: The reliability of oral rehabilitation by four zygomatic implants with no anterior support remains to be determined. The aim of this systematic review was to assess the predictability of this approach in regard to implant survival, technical and biologic complications, and quality of life. MATERIALS AND METHODS: An electronic literature search was conducted from September 2000 to November 2013. Human clinical trials in which oral rehabilitation was achieved by the use of four zygomatic implants with no additional placement of standard implants were included. The primary outcome was the survival rate of the zygomatic implants. In addition, random effects meta-analyses of the selected studies were applied to avoid potential bias caused by methodologic differences among studies. RESULTS: 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%. Only a limited number of surgical complications were reported, with orbital perforation the most significant. Similar results were obtained for prosthetic complications (few occurrences). Additionally, patient satisfaction levels were shown to be high, approaching that of the general population. CONCLUSION: Data from the present systematic review suggest that maxillary rehabilitation by four zygomatic implants with no anterior support is a reliable approach.

Prostheses supported by four immediately loaded zygomatic implants: a 3-year prospective study.

PURPOSE: To assess the clinical 3-year outcome of prostheses supported by four immediately loaded zygomatic implants. MATERIALS AND METHODS: A total of 17 consecutively treated patients (7 men, 10 women, mean age 57.7 years) with severe maxillary atrophy were immediately rehabilitated with prostheses supported by four immediately loaded zygomatic implants. The patients were followed up for 3 years and the outcome measures included success rates of the prostheses, success rates of the zygomatic implants, complications and oral-health related quality of life (OHRQoL). RESULTS: No patients dropped out. No prosthesis or zygomatic implants failed, though one implant was not used to support the final prosthesis because it emerged in an unfavourable position. Seven complications occurred: penetration of the orbital cavity during the drilling procedure with no relevant consequences; an infection followed by a fistula at one zygomatic implant, which was resolved with antibiotic treatment and surgical drainage; two patients developed sinusitis, and were successfully treated with antibiotics and meatotomy; fracture of the abutment screw occurred in one patient; and fracture of the prosthesis occurred in two patients and the definitive prostheses were repaired. The average score for the OHIP-14 questionnaire was 2.7, which was similar to that of the general population. CONCLUSIONS: The present 3-year study suggests that prostheses supported by four immediately loaded zygomatic implants can be used for successful rehabilitation of patients with severely atrophic maxillae.

Immediately loaded zygomatic implants: a 5-year prospective study.

PURPOSE: This prospective study was designed to assess the long-term outcome of immediately loaded zygomatic implants placed in atrophic maxillae. MATERIALS AND METHODS: Forty-two consecutively treated patients received 81 zygomatic implants and 140 conventional implants for oral rehabilitation and were followed for 5 years. Complete arch rehabilitation was accomplished in 37 patients and partial arch rehabilitation in 5 (one zygomatic implant in combination with two conventional implants). Outcome measures were prosthetic and implant failures, and complications. RESULTS: Twelve zygomatic and 22 conventional implants in 6 patients were not reviewed as patients were lost to follow-up. One zygomatic implant was removed at the 3-year follow-up visit because of lack of osseointegration and disturbances around the zygomatic region. The success rate of zygomatic implants was 98.5% (68/69). Six conventional implants were lost, with a success rate of 94.9% (112/118). One of the definitive prostheses was changed after 4 years of follow-up. Six complications occurred during the entire follow-up period. CONCLUSIONS: The 5-year prognosis was found to be good for immediately loaded zygomatic implants together with conventional implants in severely resorbed maxillae.

Immediate function of four zygomatic implants: a 1-year report of a prospective study.

PURPOSE: To evaluate the clinical outcome of maxillary prostheses supported by four immediately loaded zygomatic implants after 1 year of function. MATERIALS AND METHODS: Seventeen patients were consecutively included and followed up to 1 year after prosthetic loading. Patients had severely atrophic maxillae (Cawood and Howell classification C-VI and D-V or D-VI) and were rehabilitated using four immediately loaded zygomatic implants, two in each zygoma bone. Outcome measures were success rates of the prostheses, of the zygomatic implants, complications and oral health-related quality of life (OHRQoL). RESULTS: No patients dropped out. No zygomatic implants were lost, although one implant could not be used because it was placed in an unfavourable position. The orbital cavity was penetrated during the drilling procedure in one patient with no relevant clinical consequences. One patient experienced an infection followed by a fistula in one zygomatic implant, which was successfully treated. The average score from the OHIP-14 questionnaire was 3.4, which is similar to that of the general population. CONCLUSIONS: The present study suggests that four immediately loaded zygomatic implants can be used to rehabilitate patients with severely atrophied maxillae.

Zygomatic implants placed with a two-stage procedure: a 5-year retrospective study.

AIM: The zygomatic implant represents a non-grafting alternative for the oral rehabilitation of patients with extreme resorption of the maxilla. Nevertheless, there are few studies concerning their long-term prognosis. The purpose of this retrospective study was to evaluate the prosthetic rehabilitation success rate and the survival rates of machined surface zygomatic implants and conventional implants placed using a 2-stage protocol in 21 consecutively treated patients with atrophic maxillae after a 5-year followup period. MATERIALS AND METHODS: A total of 24 consecutively treated patients (8 men, 16 women), with a mean age of 51.4 years (range 36 to 72 years) were included in this study. Rehabilitations were accomplished in 22 edentulous arches, and two partially edentulous arches. In total, 45 zygomatic and 109 conventional implants were inserted. A total of 21 patients had a screw-retained fixed implant-supported prosthesis within 6 months of implant placement and three patients had an implant-supported overdenture. Outcome measures were survival rates of the prosthetic rehabilitations, of the zygomatic and conventional implants, as well as complications. RESULTS: Three patients dropped out, two after 1 year and one after 3 years. Continuous stability of the prostheses was achieved in 20 out of the 21 patients throughout the study. Therefore, the success rate for the prosthetic rehabilitation after 5 years was 95.8%. One overdenture supported on two zygomatic implants was removed after 1 year of function. The patient is currently waiting for the installation of two more zygomatic implants or a grafting procedure. One zygomatic implant was lost giving a survival rate 97.4% after the 5-year follow-up period. A total of 11 conventional implants were lost, resulting in a survival rate of 89.9% after 5 years of follow-up. Sinusitis was observed in five patients throughout the study, which was solved with antibiotics, meatotomy, or Caldwell-Luc antrostomy with no further consequences. CONCLUSIONS: Zygomatic implants together with conventional implants in the atrophic maxillae appear to have an acceptable 5-year clinical outcome.

Sinus reactions to immediately loaded zygoma implants: a clinical and radiological study.

AIM: There are no published studies regarding sinus reactions to immediately loaded zygomatic implants. The aim of this study was to evaluate the maxillary sinus in a cohort of patients by means of clinical criteria and computerised tomography performed before surgery and after zygomatic implant placement (immediate function protocol). MATERIALS AND METHODS: A total of 36 patients with 71 immediately loaded zygomatic implants were evaluated to find clinical criteria of maxillary sinus disturbance 13 to 42 months (average 21.9 months) after zygoma implant placement. A total of 44 implants had a machined surface and 27 had a porous titanium oxide surface. Twenty-six patients with 52 immediately loaded zygomatic implants were evaluated by means of a CT scan of the paranasal sinuses, 3 to 20 months (average 10.5 months) after zygomatic implant placement. All patients had no sinus symptoms before surgery and had a preoperative CT scan. RESULTS: No clinical signs or symptoms of sinusitis were found. Radiological opacity of the antrum was found in two sinuses (out of 52), and minimal thickening of the Schneiderian membrane was found in 12 patients (out of 26). In eight of them, this was present in the preoperative CT scan. CONCLUSIONS: Sinuses penetrated by zygomatic implants seem to maintain a normal physiology. However, in approximately 15 to 20% of patients, early radiological findings without clinical symptoms were observed.