The long-term use of zygomatic implants: a 10-year clinical and radiographic report

20 Years of Clinical Evolution in Zygomatic Implant Rehabilitation: Long-Term Outcomes and Current States

Zygoma implants are an alternative for rehabilitating severe maxillary atrophy. Since 2004, when Prof. Branemark first reported the long-term findings on zygomatic implants using the original intra-sinus approach, various surgical techniques have been introduced. In 2006, an anatomy-guided approach was developed, applying different implant trajectories based on alveolar atrophy levels and sinus concavity. The purpose of this review is to clarify the existing techniques and long-term outcomes of ZI rehabilitation over the past 20 years. Additionally, it aims to enhance the quality of current practices and identify gaps in the understanding of ZI treatment for future studies.

Dental rehabilitation of cleft palate patients using zygomatic implants: A case report

Edentulous patients with history of cleft palate and severe maxillary atrophy are challenging patients to rehabilitate through an oral approach. The difficulty of rehabilitating these patients lies in the unusual anatomy they present and the alteration of the vascular supply of local tissues caused by the previous performed surgeries, along with other causes. This report describes the successful dental rehabilitation with zygomatic implants of a patient with complete bilateral cleft palate who was edentulous and had severe maxillary atrophy.

Combined static and dynamic computer-guided surgery for prosthetically driven zygomatic implant placement

OBJECTIVES

To propose and validate a minimally invasive combined static and dynamic computer assisted implant surgery (CAIS) workflow for zygomatic implant (ZI) placement.

METHODS

A combined approach leveraging static CAIS for initial positioning, complemented by dynamic CAIS for real-time control of the angle, depth and width was proposed. Fourteen consecutive patients (age: 60.3±9.8 years; 8 females) seeking ZI-supported restoration were enrolled. A single anatomically and prosthetically driven ZI on either the unilateral zygoma or bilateral zygomata was planned and placed using the proposed approach. The zygomatic anatomy-guided approach (ZAGA) type and the ZI length were recorded. The angular, coronal global, and apical global deviation between the planned and placed positions were measured by overlapping post- and pre-operative cone beam computer tomography. Comparisons were made between the left and right sides across the ZAGA type and ZI length. Statistical significance was set at P<0.05.

RESULTS

22 ZIs were placed using the combined approach and 13 immediate loading prostheses were delivered, with one patient restored 6 months after surgery. The angular deviations and coronal global deviations were 1.99±0.17° and 1.21±0.45 mm, respectively. The median apical global deviation was 1.67 mm (interquartile range [IQR]: 1.11-1.93 mm). No significant differences were found between the left and right sides across the ZAGA type or ZI length. All ZIs remained stable over a median follow-up of 14.5 months (IQR: 7-20 months).

CONCLUSIONS

The proposed combination of static and dynamic CAIS is safe, reliable, accurate, and robust for ZI placement.

CLINICAL SIGNIFICANCE

This pilot study proposed a minimally invasive ZI placement method that combined static and dynamic computer-guided surgery. The implant positioning accuracy achieved using this approach validated its safety, reliability, accuracy, and robustness. The combined approach may reduce the technique sensitivity of ZI placement, facilitating future rehabilitation of severely atrophic or defective maxillae.

Pterygoid implants as alternative to bone augmentation in implant dentistry

The ultimate dental implant challenge is reconstruction of the severely resorbed maxilla, especially in patients with long-term edentulism or multiple previous failed attempts at dental implant placement and full-arch implant rehabilitation. Before implant dentistry, complete dentures, which are limited by poor retention and lack of support that the alveolar ridge offers in atrophic maxillae, were the only option for these patients. Pterygoid implants are now a valid and valuable resource for the rehabilitation of the posterior atrophic maxilla. This chapter will cover pterygoid implant surgical and pre-surgical planning, surgical procedures and protocols, including multiple techniques commonly utilised to place and restore these implants comprehensively.

[Research progress and clinical application of veneer materials for implant-fixed restoration in edentulous jaws]

Commonly used materials for fixed restorations in edentulous jaws include acrylic resins, polymerized ceramics, ceramics and zirconia, which have distinct physicochemical properties and clinical application features. The selection of these materials in clinical practice is related to the prosthodontic space, oral soft and hard tissue conditions, occlusal force, lifestyle habits, oral parafunctions, opposing dentition materials, and expectations of patients. Common mechanical complications associated with fixed restorations in edentulous jaws are cracking/chipping and abrasion of the facing materials, which can be avoided through occlusal adjustment, restoration design and processing, and the selection of appropriate restorative materials. This article reviews the characteristics, selection, and design considerations of commonly used materials for fixed restorations in edentulous jaws, as well as the causes and management of common clinical complications related to restorative materials, aiming to provide references for the selection of appropriate materials in fixed restorations for edentulous jaws in clinical practice.

Mandibular Fixed Prosthesis With a 3D-Printed Subperiosteal Implant: A Case Report

This case report aims to present the successful restoration of the atrophic partially edentulous posterior mandible using custom-made subperiosteal implants. The fixed prosthesis restoration was achieved using computer-aided design and computer-aided manufacturing technologies and 3D metal printing methods. The partially edentulous 58-year-old patient expressed a preference not to undergo bone augmentation procedures. The patient with teeth in the anterior mandible was treated with 2 separate custom-made subperiosteal implants. A custom-made implant was fabricated from sintered titanium using machined subperiosteal implants with a universal external connection. Subperiosteal implants offer several advantages over conventional bone grafting plus intraosseous implant placement techniques, such as the simple, 1-step procedure for atrophic jaws, streamlining the treatment process and reducing the overall time involved. Treatments using subperiosteal implants can be an alternative solution for individuals with severely atrophic jaws. Longer term studies in a larger sample are warranted to corroborate previous reports.

Immediate rehabilitation of severely atrophic maxillae using conventional and extended length subcrestal angulated (ELSA) implants: A retrospective analysis of 187 implants in 33 patients with up to three years of function

PURPOSE

The purpose of this study was to evaluate and determine clinical outcomes and survival rates of straight and extended length subcrestal angulated (ELSA) implants (20-24 mm lengths) placed for immediate (up to 72 h post-operative) or delayed rehabilitation (4 months post-operative) of severely atrophic maxillae. Prosthetic treatment consisted of interim and definitive implant-supported fixed implant-supported prostheses with up to 3 years of function.

MATERIALS AND METHODS

A retrospective analysis was conducted of 38 patients (five dropped out; final total was 33), treated between 2017 and 2019 in a private practice. Extended length subcrestal angulated (ELSA) implants and conventional endosseous straight implants (Southern Implants, Irene, South Africa) with (fixed) full arch prostheses were used to restore patients with edentulous maxillae immediately (within 72 hs) or delayed (4 months).  ELSA implants have subcrestal angulations of 24° and 36° of the restorative platforms, external hexagon crestal anti-rotation abutment connections, and lengths between 18 and 26 mm. Implant loading was determined by implant insertion torque values (as determined on the surgical units); 120 Ncm was the threshold level for immediate loading. Clinical and radiographic examinations were done that recorded the clinical outcomes of implants and prostheses. SPSS was used to process the data.

RESULTS

Thirty-three patients and 187 implants were included with follow-up periods of at least 12 months (range 12-36 months). The mean age of the study population was 62.6 ± 8.4 years old (at the time of implant placement). Thirty-three patients (86.8%) were followed for 12 months; 13 patients (39.4%) were followed for 24-35 months; 9 patients (27.3%) were followed for 36 months. In total, 13 implants in six patients failed secondary to sinus infections. Mean bone levels (MBLs) were respectively: 0.88 ± 2.12 mm at loading, -1.53 ± 2.03 mm at 12 months, -2.26 ± 1.45 mm at 24 months, and -2.54 ± 1.46 mm at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBL at 36 months than did the conventional implants. One hundred thirty-seven implants were placed and loaded within 72 h; 50 implants were placed and loaded 4 months post placement. The combined implant survival rates were 93.0% at 12 months, 91.1% at 24 months, and 100% at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBLs at 36 months when compared to the conventional implants.

CONCLUSIONS

The results of this retrospective clinical chart review indicated that the use of ELSA implants placed into anterior maxillae and nasal crests with accentuated distal tilts (>30°) and simultaneous sinus augmentation provided favorable outcomes for prosthetic rehabilitation in patients with severe atrophic maxillae. ELSA implants placed with simultaneous sinus augmentation are an alternative option to zygomatic implants (ZI) when immediate loading is prescribed. Sinus infections were thought to be the proximate causes of all implant failures. Further long-term clinical studies are warranted with larger patient populations.

Peri-zygomatic complications on zygomatic implants with or without penetrating the external surface of zygoma: A 2-year retrospective study

OBJECTIVES

The main purpose of this retrospective study was to assess the difference in the incidence of peri-zygomatic complications (PZCs) when zygomatic implants (ZIs) penetrate or do not penetrate the external surface of zygoma.

MATERIALS AND METHODS

This study included 32 patients with edentulous maxillae or potentially edentulous maxillae undergo zygomatic implantation. The patients were divided into the penetration group (P-group) and the non-penetration group (N-group) according to whether the apex of implants penetrated the external surface of zygoma in postoperative CBCT. The extension length, the penetration section of the implants, and the skin thickness at the corresponding position were simultaneously measured. Clinical follow-up was conducted regularly until 2 years after surgery. The occurrence of PZCs (including peri-zygomatic infection, skin numbness, non-infectious pain, and foreign body sensation) was recorded. A mixed effect logistic model was used to compare the difference of complication rate between the P-group and the N-group, and odds ratio (OR) was calculated. Then identify the impact of the extension length, penetration section and skin thickness in P-group with the same model.

RESULTS

A total of 71 ZIs were implanted in 32 patients, including 37 implants in the P-group and 34 implants in the N-group. During the 2-year follow-up, a total of 13 implants occurred PZCs, with an overall complication rate of 18.3%. Thereinto, the incidence rate was 29.7% in the P-group, and 5.9% in the N-group (OR = 6.77). In P-group, there was a significant difference in complication rate of different extension lengths, while the penetration section and skin thickness had no statistical significance on the complication rate.

CONCLUSION

Under the limitation of this study, to minimize the risk of PZCs, ZI should be placed in a manner that avoids the apex penetrating the external surface of the zygoma.

Quad Zygoma: A Graftless Solution in Post-mucormycosis Maxillectomy

Mucormycosis, a fungal infection that commonly affects individuals with diabetes and compromised immune systems, often requires surgical excision and debridement. However, this can result in significant defects, posing a challenge for clinicians in terms of reconstruction and rehabilitation. Prostheses, local and regional pedicled flaps with or without bone grafts, and titanium mesh application are available options for maxillary reconstruction. Soft-tissue flaps are not sufficient to provide osseointegrated implants with both bone repair and structural support, which emphasises the quad zygoma's beneficial role in treating maxillary abnormalities. Patients benefit from quad zygoma, which uses zygomatic implants and eliminates the need for subsequent procedures, which shortens the course of treatment and lowers costs. Because zygomatic implants are securely fixed into the zygoma, temporary prostheses can be loaded right away. Then, four to six months later, a fixed prosthesis may be introduced. Clinical results with zygomatic implants often surpass those of bone grafting, representing a potential novel gold-standard approach for the compromised maxilla. This case report details the rehabilitation of post-mucormycosis patients with maxillary defects using quad zygomatic implants. The absence of complications during follow-up, conducted at 15, 30, 45, and 90 days, and subsequently monthly for two years, highlights the success of this approach. Evaluation parameters included soft tissue recovery, infection, wound separation, stability of prosthesis, eating effectiveness, and aesthetic outcomes. The positive outcomes observed at follow-up appointment emphasize the viability and effectiveness of quad zygomatic implants in addressing maxillary defects post-mucormycosis.

Clinical outcomes of implant-supported prosthetic rehabilitation of severely atrophic maxilla: A systematic review

Aim

The purpose of this systematic review is to evaluate the clinical outcomes for the various methods of rehabilitation of a severely atrophic maxilla with the help of implant-supported fixed prosthesis.

Materials and Methods

The relevant publications published between 2013 and 2022 and written only in English were identified using an electronic search. The primary research question for this study was developed based on the PICO framework, which stands for population, intervention, control, and outcomes which was "What are the clinical outcomes of implant-supported prosthetic rehabilitation in patients with severely atrophic maxilla?" The relevancy of the articles was confirmed by examining their titles, abstracts, and complete texts to determine whether they satisfied the requirements for inclusion. Utilizing specialized study design-related bias assessment forms, the risk of bias was evaluated.

Results

The database search resulted in 1568 results; however, 1529 of them were eliminated because of insufficient, duplicate, or missing data. Additionally, manual searching yielded 11 articles. After 50 full-text papers were assessed for eligibility, 17 articles were eliminated. Thus, 33 studies in total are included in the current systematic review. Risk of bias analysis and GRADE evidence analysis were performed. Data were found to be heterogeneous and thus meta-analysis could not be done and narrative synthesis is presented.

Conclusion

The patient's condition and the clinician's expertise play a role in taking the decision on choice of technique for the fixed implant-supported rehabilitation of the severely atrophic maxilla. A high success and survival rate is produced by the majority of fixed implant-assisted prostheses despite the biologic and prosthetic problems. A single approach cannot be recommended as the gold standard. The choice is dependent on the patient's biological factors as well as the clinician's expertise. The included studies were assessed using GRADE criteria. The quality of evidence is low-medium. Therefore, to better comprehend the clinical effectiveness of the treatment alternatives, more well-designed randomized controlled trials with longer follow-up period are required.

Long-term treatment outcomes with zygomatic implants: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to perform a systematic review with meta-analysis on the long-term survival rates of zygomatic implants (ZI). ZI success, prostheses survival and success, sinus pathology and patient reported outcomes were also investigated.

METHODS

Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines were followed. Embase and OvidMedline databases were searched alongside the grey literature. The systematic review was recorded in PROSPERO (CRD42022358024). Studies reporting titanium/titanium alloy ZI survival data, ZI-supported prosthesis data, ZIs directly compared to any other implant therapy including grafted sites, a minimum follow-up time of 3 years and a minimum number of 10 patients were included. All study designs were considered if they met the inclusion criteria. Studies not involving ZIs, ZIs not made from titanium/titanium alloy, a follow-up time of < 3 years or < 10 patients, animal studies and in vitro studies were excluded. Long-term follow-up has not been defined in the literature. A minimum of 3 years follow-up was considered acceptable to capture survival after initial healing, alongside in-function prosthesis data via delayed or immediate load protocols. ZI success, was predominantly defined as ZI survival without biological or neurological complications. Meta-analyses were performed for ZI survival, ZI failure incidence, ZI success, loading protocol, prosthesis survival, and prevalence of sinusitis using random effects models. Descriptive analysis was used for ZI success, prosthesis success and patient reported outcome measures.

RESULTS

Five hundred and seventy-four titles were identified, of which 18 met the inclusion criteria. Eligible studies included 1349 ZIs in 623 patients. Mean follow-up period was 75.4 months (range 36-141.6). The mean survival of ZIs was 96.2% [95% CI: 93.8; 97.7] at 6 years. Mean survival for delayed loading was 95% [95% CI: 91.7; 97.1] and 98.1% [95% CI: 96.2; 99.0] for immediate loading (p = 0.03). Annual incidence rate of ZI failure was 0.7% [95% CI 0.4; 1.0]. Mean ZI success was 95.7% [95% CI 87.8; 98.6]. Mean prosthesis survival was 94% [95% CI 88.6; 96.9]. Sinusitis prevalence was 14.2% [95% CI 8.8; 22.0] at 5 years. Patients' reported increased satisfaction with ZIs.

CONCLUSIONS

ZIs have long-term survival comparable to conventional implants. Immediate loading showed a statistically significant increase in survival over delayed loading. Prosthesis survival was similar to that of prostheses supported by conventional implants, with similar complications. Sinusitis was the most frequently encountered biological complication. Patients reported improved outcome measures with ZI use.

Indications for zygomatic implants: a systematic review

PURPOSE

The purpose of this systematic review was to assess the evidence regarding the indications for placement of zygomatic implants to rehabilitate edentulous maxillae.

MATERIAL AND METHODS

A focused question using the PIO format was developed, questioning "in patients in need of an implant-supported rehabilitation of the edentulous maxillae, what are the indications for the use of zygomatic implants''. The primary information analyzed and collected was a clear description of the indication for the use of zygomatic implants.

RESULTS

A total of 1266 records were identified through database searching. The full-text review was conducted for 117 papers, and 10 were selected to be included in this review. Zygomatic implant indications were extreme bone atrophy or deficiency secondary to different factors. The quad zygoma concept (two zygomatic implants bilaterally placed and splinted) was applied to 107 patients, the classic zygoma concept (one zygomatic implant bilaterally placed and splinted to standard anterior implants) was used in 88 patients, and the unilateral concept (one zygomatic implant on one side, splinted with one or more conventional implants) was employed in 14 patients.

CONCLUSIONS

The main indication for the use of zygomatic implants was considered extreme maxillary bone atrophy, resulting from many factors. The clear definition of what was considered "extreme bone atrophy" is not uniquely defined in each paper. Further studies are needed to develop clear indications for zygomatic implants.

Autonomous robotic surgery for zygomatic implant placement and immediately loaded implant-supported full-arch prosthesis: a preliminary research

OBJECTIVES

A patient with extensive atrophy of the alveolar ridge in the posterior portion of the maxilla was selected to complete an experimental and clinical case of the robotic zygomatic implant to investigate the viability of an implant robotic system in clinical use.

METHODS

The preoperative digital information was collected, and the implantation position and personalized optimization marks needed for robot surgery were designed in advance in a repair-oriented way. The resin models and marks of the patient's maxilla and mandible are all printed in 3D. Custom-made special precision drills and handpiece holders for robotic zygomatic implants were used to perform model experiments and compare the accuracy of the robotic zygomatic implant group (implant length = 52.5 mm, n = 10) with the alveolar implant group (implant length = 18 mm, n = 20). Based on the results of extraoral experiments, a clinical case of robotic surgery for zygomatic implant placement and immediate loading of implant-supported full arch prosthesis was carried out.

RESULTS

In the model experiment, the zygomatic implant group reported an entry point error of 0.78 ± 0.34 mm, an exit point error of 0.80 ± 0.25 mm, and an angle error of 1.33 ± 0.41degrees. In comparison, the alveolar implant group (control group) reported an entry point error of 0.81 ± 0.24 mm, an exit point error of 0.86 ± 0.32 mm, and an angle error of 1.71 ± 0.71 degrees. There was no significant difference between the two groups (p > 0.05). In clinical cases, the average entry point error of two zygomatic implants is 0.83 mm, the average exit point error is 1.10 mm and the angle error is 1.46 degrees.

CONCLUSIONS

The preoperative planning and surgical procedures developed in this study provide enough accuracy for robotic zygomatic implant surgery, and the overall deviation is small, which is not affected by the lateral wall deviation of maxillary sinus.

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.

Accuracy of computer-aided static and dynamic navigation systems in the placement of zygomatic dental implants

BACKGROUND

Zygomatic implants are widely used in the rehabilitation of severely atrophic maxillae, but implant placement is not without risks, and it can potentially cause damage to related anatomical structures. The aim of this study was to perform a comparative analysis of the accuracy of static navigation systems in placing zygomatic dental implants in comparison to dynamic navigation systems.

METHODS

Sixty zygomatic dental implants were randomly allocated to one of three study groups, categorized by which implant placement strategy was used: A: computer-aided static navigation system (n = 20) (GI); B: computer-aided dynamic navigation system (n = 20) (NI); or C: free-hand technique (n = 20) (FHI). For the computer-aided study groups, a preoperative cone-beam computed tomography (CBCT) scan of the existing situation was performed in order to plan the approach to be used during surgery. Four zygomatic dental implants were inserted in each of fifteen polyurethane stereolithographic models (n = 15), with a postoperative CBCT scan taken after the intervention. The pre- and postoperative CBCT scans were then uploaded to a software program used in dental implantology to analyze the angular deviations, apical end point, and coronal entry point. Student's t-test was used to analyze the results.

RESULTS

The results found statistically significant differences in apical end-point deviations between the FHI and NI (p = 0.0053) and FHI and GI (p = 0.0004) groups. There were also statistically significant differences between the angular deviations of the FHI and GI groups (p = 0.0043).

CONCLUSIONS

The manual free-hand technique may enable more accurate placement of zygomatic dental implants than computer-assisted surgical techniques due to the different learning curves required for each zygomatic dental implant placement techniques.

Assessment of the content and quality of YouTube videos related zygomatic implants: A content-quality analysis

INTRODUCTION

This study aimed to evaluate the content and quality of YouTube videos of zygomatic implants.

METHODS

According to Google Trends (2021), "zygomatic implant" was the most preferred keyword related to the topic. Therefore, in this study "zygomatic implant" was used as a keyword for the video search. Demographic characteristics such as the number of views, likes/dislikes, comments, video duration, number of days after upload, uploaders, and target audiences of the videos were evaluated. To evaluate the accuracy and content quality of videos (available from YouTube), the video information and quality index (VIQI) and global quality scale (GQS) were used. Statistical analyses were performed using the Kruskal-Wallis test, Mann-Whitney U test, chi-square test, Fisher's exact chi-square test, Yates continuity correction, and Spearman correlation analysis (p < 0.05).

RESULTS

A total of 151 videos were searched; 90 met all inclusion criteria. According to the video content score, 78.9% of the videos were identified as low content, 20% as moderate, and 1.1% as high content. There was no statistical difference between the groups in video demographic characteristics (p > 0.001). Conversely, information flow, accuracy of information, video quality and precision, and total VIQI scores were statistically different between the groups. The moderate-content group had a higher GQS score than the low-content group (p < 0.001). The videos were mainly uploaded (40%) from hospitals and universities. Most videos were targeted toward professionals (46.75%). Low-content videos had higher ratings than the moderate- and high-content videos.

CONCLUSIONS

Most YouTube videos on zygomatic implants showed low-content quality. This implies that YouTube is not a reliable source of information on zygomatic implants. Dentists, prosthodontists, and oral and maxillofacial surgeons should be aware of the content of video-sharing platforms and take responsibility for enriching video content.

Retrospective cohort assessment of survival and complications of zygomatic implants in atrophic maxillae

OBJECTIVES

To report on zygomatic implant (ZI) survival rate and associated complications through a longitudinal retrospective cohort assessment.

MATERIAL AND METHODS

A total of 940 ZIs (rough: 781, machined: 159; immediate loading: 454, delayed loading: 486) and 451 standard implants (rough: 195, machined: 256; immediate loading: 58, delayed loading: 393) were placed in 302 adult patients with atrophic maxilla from December 1998 till September 2020. Following data collection reported complications were grouped based on their origin as infectious/ non-infectious biological and mechanical. Statistical analysis was performed to identify risk factors and preceding complications leading to implant loss (P < 0.05).

RESULTS

The survival rate of ZI was found to be 89.9% and the average time between implant placement and an eventual loss was 4.8 years. The mean ZI follow-up period was 7.9 ± 4.9 years. Amongst the infectious biological complications, sinusitis was the most reported (n = 138) occurring at a mean follow-up time-point of 4.5 years, whereas infraorbital nerve hypoesthesia occurred more frequently in the non-infectious biological category (n = 8, meantime: 0.3 years). The prosthetic screw fracture was the most reported complication of mechanical origin (n = 29, meantime: 4 years). Furthermore, sinusitis, standard implant loss, zygomatic/peri-zygomatic region infection, and oroantral communication were significantly associated with ZI loss.

CONCLUSIONS

ZI placement offered a high survival rate for the rehabilitation of severely atrophied maxilla with most losses occurring within the first 5 years at follow-up. The most frequently observed complication was sinusitis which tends to develop several years following implant placement.

Survival and complications of zygomatic implants compared to conventional implants reported in longitudinal studies with a follow-up period of at least 5 years: A systematic review and meta-analysis

BACKGROUND

Zygomatic implants (ZI) have been frequently indicated to rehabilitate patients with extensive atrophies in alternatives to major bone reconstructions. It can be installed inside the maxillary sinus, called instrasinus zygomatic implant (IZI) or outside the maxillary sinus (EZI), depending on the surgery technique.

OBJECTIVE

To evaluate the survival and complication rates of ZI in longitudinal studies when compared with conventional implants (CI).

METHODS

An electronic search was performed in five databases and in Gray literature for articles published until April, 2022. The eligibility criteria comprised observational cohort studies (prospective or retrospective) and randomized clinical trials (RCTs) with at least 5 years of follow-up, reporting survival rate of ZI versus CI. A meta-analysis was conduct with 18 studies.

RESULTS

A total of 5434 implants (2972 ZI and 2462 CI) were analyzed in 1709 patients. The mean survival rate was 96.5% ± 5.02 and 95.8% ± 6.36 for ZI and CI, respectively (mean follow-up time of 78 months). There were observed no statistically significant between ZI and CI in prospective studies (risk ratio [RR] of 1.21; 95% confidence intervals [CIs]: 0.28 to 5.28; chi-squared [Chi² ] = 11.37; I²  = 56%; degrees of freedom [df] = 5; z-score = 0.25; P = 0.80), retrospective studies IZI (RR of 1.29; 95% CIs: 0.52 to 3.23; Chi²  = 4.07; I²  = 2%; df = 4; z-score = 0.55; P = 0.58) and retrospective studies EZI (RR of 0.72; 95% CIs: 0.31 to 1.66; Chi²  = 1.99; I²  = 0%; df = 3; z-score = 0.78; P = 0.44). The biological complications most related to ZI was sinusitis, followed by infection and oroantral communication.

CONCLUSION

ZI have a high long-term survival rate (96.5% with a mean of 91.5 months of follow-up), showing no significant difference when compared with CI. The most prevalent biological complication is sinusitis, being most commonly to the IZI technique. This systematic review (SR) was registered in INPLASY under number INPLASY202280025.

A novel technique to quantify bone-to-implant contact of zygomatic implants: a radiographic analysis based on three-dimensional image registration and segmentation

OBJECTIVES

The purpose of this study is to establish a novel, reproducible technique to obtain the BIC area (BICA) between zygomatic implants and zygomatic bone based on post-operative cone-beam computed tomography (CBCT) images. Three-dimensional (3D) image registration and segmentation were used to eliminate the effect of metal-induced artifacts of zygomatic implants.

METHODS

An ex-vivo study was included to verify the feasibility of the new method. Then, the radiographic bone-to-implant contact (rBIC) of 143 implants was measured in a total of 50 patients. To obtain the BICA of zygomatic implants and the zygomatic bone, several steps were necessary, including image preprocessing of CBCT scans, identification of the position of zygomatic implants, registration, and segmentation of pre- and post-operative CBCT images, and 3D reconstruction of models. The conventional two-dimensional (2D) linear rBIC (rBICc) measurement method with post-operative CBCT images was chosen as a comparison.

RESULTS

The mean values of rBIC and rBICc were 15.08 ± 5.92 mm and 14.77 ± 5.14 mm, respectively. A statistically significant correlation was observed between rBIC and rBICc values ([Formula: see text]=0.86, p < 0.0001).

CONCLUSIONS

This study proposed a standardized, repeatable, noninvasive technique to quantify the rBIC of post-operative zygomatic implants in 3D terms. This technique is comparable to conventional 2D linear measurements and seems to be more reliable than these conventional measurements; thus, this method could serve as a valuable tool in the performance of clinical research protocols.

Patient-reported outcomes in patients with severe maxillary bone atrophy restored with zygomatic implant-supported complete dental prostheses: a systematic review

Introduction and Objective: Zygomatic implants (ZI) offer a good and predictable alternative to reconstructive procedures of atrophic maxillae. The main objetive of this systematic review was to assess the effect of rehabilitation with zygomatic implants on patient's quality of life (QLP) using Patient Reported Outcomes Measures (PROMs).Materials and Methods: This review followed PRISMA guidelines. An automated electronic search was conducted in four databases supplemented by a manual search for relevant articles published until the end of January 2021. The Cochrane Collaboration Risk of Bias tool and the Newcastle-Ottawa Quality Assessment Scale were used to assess the quality of evidence in the studies reviewed.Results: General findings of this systematic review showed substantial increases in Oral health-related quality of life (OHRQoL) among patients restored with ZI and high scores in terms of general satisfaction, especially in chewing ability and esthetics. An overall survival rate of ZI was 98.3% after a mean follow-up time of 46.5 months was observed. Occurrence of 13.1% biological complications and 1.8% technical complications were reported.Conclusions: Patients rehabilitated with zygomatic implant-supported complete dental prostheses showed substantial improvements in OHRQoL and general satisfaction with the treatment received.

Survival of conventional dental implants in the edentulous atrophic maxilla in combination with zygomatic implants: a 20-year retrospective study

PURPOSE

Implant-supported prosthetic rehabilitation in the resorbed maxilla is a great challenge. The aim of this study was to determine the survival rate of conventional anterior implants placed in combination with zygomatic implants according to the Brånemark technique, and to identify risk factors for implant failure.

METHODS

We collected data retrospectively from 72 consecutive patients who received treatment from 1998 to 2018 at our center, according to Brånemark's original technique. Kaplan-Meier analysis was conducted to assess survival rate, and a survival regression model was used with the patient as the random factor, applying the Weibull distribution.

RESULTS

A total of 236 maxillary anterior implants were included, with a mean follow-up of 12.1 years. Kaplan-Meier analysis showed overall cumulative survival rates of 95.3% at 1 year, 94.8% at 2 years, 93.0% at 5 years, 90.5% at 10 years, 81.6% at 15 years, and 67.7% at 20 years. Survival regression showed an association between bruxism and implant failure as well as implants bearing an overdenture. Implants with length ≤ 10 mm had a significantly lower survival time. No significant association was found between the number of anterior implants and survival rate.

CONCLUSIONS

We found acceptable long-term anterior conventional implant survival. Significant risk factors for failure were bruxism, overdentures, and implants shorter than 10 mm.

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.

Maxillary Sinusitis as a Complication of Zygomatic Implants Placement: A Narrative Review

Aims: The aim of this review is to consider maxillary sinusitis as a complication of zygomatic implants placements. Maxillary sinusitis a common complication but in the literature there are no reviews that focus only on this condition and its possible treatment. This review was carried out with to highlight the main findings of the literature on this topic and to improve knowledge in this field. Methods: The search strategy resulted in 155 papers. After selection of the inclusion criteria only 11 papers were examined. From the papers these, 12.3% patients presented maxillary sinusitis but only four studies evaluated sinusitis (both clinical and radiological evaluation). The most common treatment used by the authors were antibiotics alone or combined with functional endoscopic sinus surgery (FESS). Results: The literature shows an absence of precise and shared guidelines diagnosis and post-operative follow-up, and of the treatment of maxillary sinusitis following zygomatic implantology. It has not been determined if the surgical placement of ZIs is better than the other techniques for treatment of the onset of maxillary sinusitis in the post-operative period. Conclusion: To date there are no shared protocols for maxillary sinusitis treatment. In our experience, and according to the literature in the presence of risk factors such as age, comorbidities, smoking, nasal septal deviation or other anatomical variants, we suggested that FESS is performed at the same time as placement of zygomatic implants.

Retrospective Analysis of Clinical and Radiologic Data Regarding Zygomatic Implant Rehabilitation with a Long-Term Follow-Up

BACKGROUND

Zygomatic implants have been introduced to rehabilitate edentulous patients with severely atrophic maxillae. Their use has been reported by several studies, describing high overall survival rates at medium-long follow-up. The aim of this study was to retrospectively analyze if a few patient-related and implant-related features are correlated with implant success or the onset of complications.

MATERIALS AND METHODS

Data of patients treated with zygomatic implants between May 2005 and November 2012 at three private clinics were collected and retrospectively analyzed. For each implant, the following data were collected: implant length, insertion path, ridge atrophy and sinus characteristics (width, pneumatization, thickness of mucosae, patency of sinus ostium). General patient characteristics and health status data were also recorded. The outcomes evaluated were implant failure, infective complications, early neurologic complications and overall complications.

RESULTS

A total of 33 patients (14 men, 17 women, mean age 59.1) that received 67 zygomatic implants were included in the study. The mean duration of the follow-up was of 141.6 months (min 109; max 198). In this period, a total of 16 (23.88%) implants in 8 (24.24%) patients were removed and 17 (51.51%) patients with 36 (53.73%) implants reported complications. Immediate loading resulted in a significantly lower risk of complications compared with the two-stage prosthetic rehabilitation (OR: 0.04, p = 0.002). A thickness of the sinus mucosa > 3 mm emerged to be correlated with a greater occurrence of infective complications (OR: 3.39, p = 0.019). Severe and extreme pneumatization of the sinus was significantly correlated with the incidence of overall complications (p = 0.037) and implant failure (p = 0.044). A large sinus width was predisposed to a higher risk of neurologic complications, infective complications and implant failure (p = 0.036, p = 0.032, p = 0.04, respectively).

CONCLUSIONS

zygomatic implants are an alternative procedure for atrophic ridge rehabilitation when a conventional implant placement is not possible. Several clinical and anatomical factors can have a significant role in complication occurrence.

A single-arm clinical trial investigating the feasibility of the zygomatic implant quad approach for Cawood and Howell Class 4 edentulous maxilla: An option for immediate loading

INTRODUCTION

The traditional way to treat maxillary edentulous Cawood and Howell Class 4 (CH4) patients who exhibit the knife-edge ridge form of edentulous jaws that are adequate in height and inadequate in width is extensive autologous bone grafting for conventional implant placement.

PURPOSE

To evaluate the feasibility of the zygomatic implant (ZI) quad approach in edentulous CH4 patients who presented a knife-edge ridge form in the anterior maxilla for immediate loading.

MATERIAL AND METHODS

Eligible patients with maxillary CH4 edentulism treated with the ZI quad approach were enrolled. Bone reduction and implant placement were performed under the guidance of a navigation system according to preoperative planning. The outcome variable was the implant survival rate, and additional variables were the ratio of immediate loading, complications and the relationship of the zygomatic implant path to the sinus wall. Statistical analysis was performed with the SAS statistical package.

RESULTS

Fifteen patients (3 men, 12 women; age range, 19-71 years; average age 47.2 years) eligible for the study received the ZI quad approach from January 2017 through January 2020. All ZIs achieved osseointegration, with no implant loss after early healing and a mean follow-up of 17.2 ± 6.2 months. Thirteen of 15 patients (86.7%) received immediate loading. No critical anatomic structure injuries occurred during surgery. Most mesially placed implants (23/30, 76.6%) presented ZAGA 2 and 3, and most distally placed implants were distributed in ZAGA 0 (20/30, 66.7%).

DISCUSSION

In terms of realizing immediate loading in CH4 patients with a knife-edge ridge form in the anterior maxilla, quad approaches have advantages over other grafting methods. At the same time, it seems the survival rate of zygomatic implants is comparable with that of other indications. With the limitations of this study, the quad approach might be a feasible option to realize edentulous maxillary reconstruction and to make immediate loading possible.

Survival Rate and Prosthetic and Sinus Complications of Zygomatic Dental Implants for the Rehabilitation of the Atrophic Edentulous Maxilla: A Systematic Review and Meta-Analysis

Simple Summary

Zygomatic dental implants have been proposed as an alternative to atrophic total edentulous maxillae rehabilitation with the necessity of bone grafting procedures. However, surgical, prosthetic, and maxillary sinus complications have been associated with this surgical procedure. Therefore, it is necessary to produce a systematic review and meta-analysis that provides evidence associated with the prognosis when using zygomatic dental implants as an alternative to atrophic total edentulous maxillae rehabilitation.

Abstract

The aim of this systematic review and meta-analysis was to analyze and compare the survival rate and prosthetic and sinus complications of zygomatic dental implants for the rehabilitation of the atrophic edentulous maxilla. Materials and methods: We conducted a systematic literature review and meta-analysis, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, of clinical studies that evaluated the survival rate and prosthetic and sinus complications of zygomatic dental implants for the rehabilitation of the atrophic edentulous maxilla. Four databases were consulted during the literature search: Pubmed–Medline, Scopus, Embase, and Web of Science. After eliminating duplicate articles and applying the inclusion criteria, 46 articles were selected for the qualitative analysis and 32 for the quantitative analysis. Results: Four randomized controlled trials, 19 prospective clinical studies, 20 retrospective studies, and 3 case series were included in the meta-analysis. Conventional dental implants failure (n = 3549) were seen in 2.89% (IC-95% 1.83–3.96%), while zygomatic dental implants failure (n = 1895) were seen in 0.69% (IC-95% 0.21–1.16%). The measure of the effect size used was the Odds Ratio, which was estimated at 2.05 with a confidence interval of 95% between 1.22 and 3.44 (z test = 2.73; p-value = 0.006). The failure risk of conventional dental implants is 2.1 times higher than that of zygomatic dental implants. Slight heterogeneity was determined in the meta-analysis between 23 combined studies (Q test = 32.4; p-value = 0.070; I² = 32.1%). Prosthetic complications were recorded in 4.9% (IC-95% 2.7–7.3%) and mild heterogeneity was observed in a meta-analysis of 28 combined studies (Q test = 88.2; p-value = 0.001; I² = 69.4%). Sinus complications were seen in 4.7% (IC-95% 2.8–6.5%) and mild heterogeneity was observed in a meta-analysis of 32 combined studies (Q test = 75.3; p-value = 0.001; I² = 58.8%). Conclusions: The high survival rate and low prosthetic and sinus complications related to zygomatic dental implants suggest the use of zygomatic dental implants for the rehabilitation of the atrophic edentulous maxilla.

Implant-Prosthetic Rehabilitation of a Patient with Squamous Cell Carcinoma: A Case Report

Patients who have undergone maxillary resection procedures are rehabilitated with dental obturators or microvascular reconstruction. This case report describes implant-supported prosthetic rehabilitation of a patient who underwent maxillary resection due to squamous cell carcinoma. After maxillectomy surgery, the patient was rehabilitated using a surgical obturator for one week followed by an interim obturator until the surgical field was completely healed. For definitive prosthesis, different treatment options were presented from which the patient selected an implant-supported maxillofacial prosthesis and a removable mandibular partial prosthesis. Under general anesthesia, two zygomatic implants and four conventional implants to the posterior maxilla were inserted. After a healing period, the bar-retained maxillofacial prosthesis and removable mandibular partial denture were fabricated. The patient was satisfied with regard to function, esthetics, speech, and swallowing. No problems, except slight discoloration of the prosthesis were noted at the 6-month follow-up. Implant-supported maxillofacial prostheses are a valuable treatment option to improve   quality of life after maxillary resection.

Survival Rate of Zygomatic Implants for Fixed Oral Maxillary Rehabilitations: A Systematic Review and Meta-Analysis Comparing Outcomes between Zygomatic and Regular Implants

Background: Zygomatic implants have been proposed alone or in combination with premaxillary conventional implants for severe resorbed maxillary atrophy rehabilitation. The aim of the present investigation was to evaluate through a qualitative systematic review and meta-analysis the survival rate of zygomatic implants in conjunction with regular fixtures for maxillary rehabilitation. Methods: The article screening was conducted on the PubMed/Medline and EMBASE electronic databases according to the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) guidelines. The scientific papers were included for qualitative analysis and risk-of-bias evaluation. Only the papers that included rehabilitation with zygomatic implants in combination with regular implants were considered for the meta-analysis comparative evaluation of the implant survival rate. Results: The paper search screened a total of 137 papers. After the initial screening, a total of 32 articles were considered for the qualitative analysis. There was a similar implant survival rate between zygomatic and premaxilla regular implants (p = 0.02; Z: 2.26). Conclusions: Zygomatic and conventional implants showed a high long-term survival rate for fixed maxillary rehabilitations, but few included studies reported the marginal bone loss after loading. Further studies are necessary to evaluate the pattern of marginal bone loss between zygomatic and conventional implants after long-term functional loading.

Combined bone- and mucosa-supported 3D-printed guide for sinus slot preparation and prosthetically driven zygomatic implant placement

The use of zygomatic implants to rehabilitate the severely atrophic maxilla has been well documented since first being introduced by Brånemark. Placement of zygomatic implants is technically complex, with catastrophic complications and numerous prosthetic challenges resulting from imprecise placement. The purpose of this report was to demonstrate a technique that allows transfer of the preoperatively planned sinus slot position to the surgical field by using cone beam computed tomography (CBCT) and an implant planning software program to fabricate a combined bone- and mucosa-supported 3D-printed surgical guide. This facilitates optimal zygomatic implant positioning and promotes favorable biomechanics with a predictable prosthetic outcome.

Long transmaxillary implants improve oral health-related quality of life of patients with atrophic jaws-a case series

Background

The advancement of contemporary dentistry is related to the improvement of existing techniques, materials, and technology, consistently for improving people’s oral health, which can ultimately reflect better quality of life. This study aimed to evaluate the oral-health-related quality of life (OHRQoL) of patients with atrophic jaws, who reported for the placement of long transmaxillary implants and posterior prosthetic rehabilitation. Twelve patients (n = 12), of both sexes, with a mean age of 55.83 ± 2.78 years, who were unable to receive conventional implants immediately because of lack of bone, received two long transmaxillary implants in a horizontal position, anteroposteriorly, one on each side, from the canine pillar to the maxillary tuberosity. After 6 months, the conventional clinical sequence for fabricating a fixed prosthesis type protocol or removable prosthesis type overdenture (MK1® system) was performed, when required to recover the lip volume. The Oral Health Impact Profile questionnaire (OHIP-14) was applied preoperatively and 6 months after rehabilitation using a prosthesis on the implants. The results were statistically analyzed using a significance level of 0.05.

Results

An improvement in the perception of OHRQoL was observed between the pre- and postoperative periods in the OHIP-14 total score and the domains related to functional limitation, physical pain, psychological discomfort, psychological disability, social disability, and handicap (p < 0.05).

Conclusion

It may be concluded that transmaxillary implant rehabilitation improves the OHRQoL.

The Role of Custom-made Subperiosteal Implants for Rehabilitation of Atrophic Jaws - A Case Report

Rehabilitation of atrophic jaws with conventional endosseous implant-supported overdentures and immediate loading protocols still presents a challenge nowadays. Custom-made implants with immediate loading overdenture are emerging as a solution for atrophic jaws rehabilitation. The authors describe the case of a 44-year-old male with a history of congenital dental agenesis. A previous oral rehabilitation with an all-on-6 type, implant-fixed mandibular overdenture, had failed due to peri-implantitis. The patient was successfully treated with bimaxillary custom-made subperiosteal implants with an innovative design, combining subperiosteal and endosseous support. The authors consider custom-made subperiosteal implants, in selected patients, present several advantages over classic bone-grafting plus endosseous implant-placement techniques such as (1) possibility of a single-stage procedure with immediate loading in atrophic jaws; (2) possible primary option to approach atrophic jaws as a simpler and less time-consuming technique; and (3) a valid rescue option for failed endosseous implants. More long-term studies with large samples of patients will be necessary to confirm previous assumptions.

Full arch rehabilitation in patients with atrophic upper jaws with zygomatic implants: a systematic review

Background

The main objective of this systematic review was to present the outcomes of the treatment with zygomatic implants (ZIs) in the rehabilitations of atrophic upper jaw.

Findings

An electronic database search in PubMed, along with a manual search, taking into account language and study period, was performed by two observers; any type of clinical trial and series that included the use of ZIs was used. In the search strategy, the following search terms were used: zygom* AND dental (Implant OR implants) AND edentulous NOT (biomechanic* OR finite element) NOT cadaver. The search was limited to English language, full text, and humans. Literature reviews and clinical case reports were not considered. Forty-two articles published between March 2003 and April 2019 were included in this analysis. The cases of 1247 patients were recovered; these patients received 2919 ZIs. Fifty-two ZIs were removed during the follow-up time. The survival rate of these implants was 98.22%, with a minimum follow-up of 1 month and a maximum of 228 months. Different surgical techniques were used to place ZIs; however, the intrasinusal technique was the most used (23 studies). Post-surgical sinusitis was the most common complication reported in the studies (39 cases).

Conclusions

Based on this review, ZIs were commonly used for rehabilitation of patients with atrophic upper jaw. The survival rates presented were high, and the surgical technique is dependent on the professional experience and the local anatomy. However, it needed additional clinical evidence on bone resorption, esthetic outcomes, and physiological characteristics.

Complications related to zygomatic implants placement: A retrospective evaluation with 5 years follow-up

This retrospective study assessed zygoma implants in patients treated for upper maxilla extreme atrophy, trauma, cleft palate, or failed reconstruction. The implants were placed using Quad (4 zygoma implants) or mixed (zygoma and conventional implants in premaxilla) surgical technique, with intra-sinus or extra-sinus approach, followed by immediate or deferred loading. Clinical and radiographic evaluations were carried out at 5-year follow-up from loading. Implant survival, symptoms and signs of sinusitis, radiological alterations in terms of mucosal thickening or obliteration of the maxillary sinuses, oroantral communications, and peri-implant soft tissues were examined. A total of 42 patients, with 116 zygoma implants, were included in the study. The cumulative survival rate was 97.41%. One zygomatic bone fracture was assessed. Eight patients reported sinusitis, and two showed oro-antral communications. A comparison between mean pre- and post-operative Lund-Mackay scores showed a statistically significant increase of sino-nasal disease in the post-operative scores (p = 0.0019). Mucositis and gingival recession was observed in 21 and 8 implants respectively. Average recession was 2.52 ± 2.35 mm. According to our results, placement of zygoma implants has proved to be a predictable procedure, with a lower rate of severe complications compared to other treatment options in extreme upper jaw atrophy.

Extrasinus Zygomatic Implants for the Immediate Rehabilitation of the Atrophic Maxilla: 1-Year Postloading Results From a Multicenter Prospective Cohort Study

PURPOSE

The use of zygomatic implants is an alternative to major grafting procedures for the treatment of the atrophic posterior maxilla. However, only few studies reported solid and correct data about the use of extrasinus zygomatic implants. Starting from these considerations, this study aims to investigate the 1-year survival and success rates of extrasinus zygomatic implants immediately loaded in patients with severe atrophy of the posterior maxilla.

METHODS

Twenty-three consecutive patients fully edentoulus or with failing dentition in the upper arch and with a severe atrophy of the posterior maxilla were enrolled. All patients underwent prosthodontic rehabilitation with the application of implants in both anterior maxilla areas and zygomatic bone. All the zygomatic implants were inserted with an extrasinus path. Primary outcomes were prosthesis and implant failures. Secondary outcomes were complications, bleeding scores, probing pocket depths, and peri-implant marginal bone-level changes. A total of 98 implants were inserted.

RESULTS

During the 1-year follow-up, no implant failure was reported as well as no pain and/or no sinusitis were detected. No other significant events were reported, except for minor soft tissue and technical problems. A maxillary sinus membrane rupture occurred during the surgical phase in 4 (17.4%) patients, but healing was not compromised. Peri-implant mucositis was observed in 2 (8.7%) patients. Twelve months after surgery, average bone loss around conventional implants was 1.11 ± 0.23 mm. In addition, no peri-implant radiolucency was observed around zygomatic implants. Within the limits of this study, preliminary short-term data (1-year after loading) suggested that extrasinus zygomatic implants represent a predictable treatment option for the atrophic maxilla. Further follow-up data (≥5 years) are needed to confirm these results.

CONCLUSIONS

The present study supports the conclusion that extrasinus zygomatic implants for the immediate rehabilitation of the atrophic maxilla have high success rate with minimal or no complications.

Zygomatic implant survival in 9 ectodermal dysplasia patients with 3.5- to 7-year follow-up

OBJECTIVE

Ectodermal dysplasia syndrome is a complex group of genetic disorders identified by the abnormal development of the ectodermal structures. The aim of this retrospective clinical case series report was to evaluate the outcomes of the ectodermal dysplasia syndrome patients that underwent zygomatic implant surgery.

MATERIALS AND METHODS

A total of 9 ectodermal dysplasia syndrome patients aged between 21 and 56 years (mean age 36.8) with severely atrophic maxilla were included in this study. All the patients were treated with a total of 19 zygomatic implants. The mean follow-up of the patients was 55 months (with a range of 44-84 months). The implant survival rate was evaluated as a primary outcome. The intra- and postoperative complications were evaluated as additional criteria for success.

RESULTS

The overall implant survival rate was 100% without any complications. Final or provisional prosthesis was delivered on the same day of surgery, which resulted in an improvement of the quality of life of the patients.

CONCLUSION

According to the results of this study, zygomatic surgery can be considered as a viable and safe alternative to conventional treatment modalities for oral rehabilitation of ectodermal dysplasia syndrome patients.

Does Middle Meatal Antrostomy Prevent the Onset of Maxillary Sinusitis After Zygomatic Implant Placement?

PURPOSE

To evaluate the role of middle meatal antrostomy in preventing the onset of maxillary sinusitis after placement of zygomatic implants. We hypothesized that middle meatal antrostomy might reduce the incidence of this complication.

MATERIALS AND METHODS

A prospective longitudinal study was performed of patients who had undergone placement of 4 zygomatic implants and concurrent middle meatal antrostomy with an endoscopic approach at the maxillofacial surgery unit of Verona University. The radiological results of the maxillary sinuses were evaluated on computed tomography scans performed 12 months after surgery using the Lund-Mackay staging system. Clinical symptoms were evaluated both preoperatively and 12 months after surgery using the Sino-Nasal Outcome Test-20 (SNOT-20). Intraoperative violation of the Schneiderian membrane was also assessed. The outcomes from the present study were compared with historical controls.

RESULTS

The sample included 13 patients, 26 maxillary sinuses with negative radiologic findings of sinonasal pathologic features, and 52 zygomatic implants. A moderate increase was found in radiologic findings of sinonasal pathologic features postoperatively compared with preoperatively, with mucosal hypertrophy in 3 maxillary sinuses (11.5%). The incidence and severity of mucosal hypertrophy was significantly lower than the outcomes of the historical controls. The average preoperative SNOT-20 score was 13.45, and the postoperative SNOT-20 score was 1.18. The Schneiderian membrane was pierced in 13 sinuses in 9 patients.

CONCLUSIONS

Shrinkage of the ostiomeatal complex seems to play a fundamental role in the onset of sinonasal pathologic features after zygomatic implant placement compared with implant-related causes. Although functional endoscopic sinus surgery is a supplementary surgical method in implant placement, it seems to provide statistically significant improvement in the health of the sinonasal system. Perforation of the Schneiderian membrane does not appear to correlate with the onset of sinus opacification and sinonasal symptoms.

Oral Rehabilitation with Zygomatic Implants in a Patient with Cleft Palate

Edentulous patients with an atrophic maxilla associated with lip-palate fissures have unpredictable results after undergoing grafting procedures. In situations where the atrophic maxilla does not adequately allow reconstruction, the use of zygomatic implants has been indicated, and probably these implants can be indicated for the rehabilitation of patients with lip-palate fissures. This case report describes the oral rehabilitation treatment of a patient with a lip-palate cleft treated with zygomatic implants and implant-supported fixed prosthesis with two years of follow-up. A 65-year-old female patient had a lip-palate cleft and previously underwent surgery to close the cleft. The patient had a severely atrophic maxilla and had difficulty adapting to a removable total prosthesis. Due to the small amount of bone remaining and extensive fibrous tissue in the palate region, a rehabilitation with conventional implants associated with zygomatic implants was chosen. Two zygomatic implants and a conventional implant were placed on the right side, and a zygomatic implant and conventional implant were placed on the left side; these implants were later activated by a protocol-type prosthesis. The zygomatic implants provided an adequate aesthetic and functional outcome of the prosthesis in a patient with cleft palate.

A new surgical and technical approach in zygomatic implantology

Purpose

Different surgical approaches for zygomatic implantology using new designed implants are reported.

Material and methods

The surgical technique is described and two cases reported. The zygomatic fixture has a complete extrasinus path in order to preserve the sinus membrane and to avoid any post-surgical sinus sequelae.

Results

The surgical procedure allows an optimal position of the implant and consequently an ideal emergence of the fixture on the alveolar crest.

Conclusion

The surgical procedures and the zygomatic implant design reduce remarkably the serious post-operative sequelae due to the intrasinus path of the zygomatic fixtures.

Long-term Schneiderian membrane thickness changes following zygomatic implant placement: A retrospective radiographic analysis using cone beam computed tomography

OBJECTIVES

The purpose of this retrospective study was to evaluate the long-term changes in the thickness of Schneiderian membranes after zygomatic implant placement using cone beam computed tomography (CBCT).

MATERIAL AND METHODS

Twenty-five consecutive patients were included in this study. All the patients underwent bilateral zygomatic implant placement. Schneiderian membrane thickness (SMT) in 49 maxillary sinuses (one sinus was not included because of early loss of the zygomatic implants) was measured using CBCT before and at least 1 year after zygomatic implant placement. Ostium patency of each sinus was also evaluated and recorded.

RESULTS

In total, 84 zygomatic implants and 30 regular implants were placed in included patients. Two unilateral maxillary zygomatic implants in one patient were removed 2 months after implant placement. The SMT increased from 1.03 mm (inter-quartile range: 1.57 mm) to 1.33 mm (inter-quartile range: 1.98 mm) after a median follow-up time of 23.00 months (inter-quartile range: 14 months), and the difference was statistically significant. Before zygomatic implant insertion, 24.5% (12/49) of sinuses had SMT greater than 2 mm, whereas this value was 28.6% (14/49) after zygomatic implant placement. The percentage of sinuses observed with ostium patency also increased from 2.0% (1/49) to 12.2% (6/49).

CONCLUSIONS

Chronic Schneiderian membrane thickening could result from zygomatic implant insertion. Intensive postoperative care and clinical and radiographic monitoring are recommended after zygomatic implant placement.

Avaliação da satisfação de reabilitações com implantes zigomáticos

Resumo Introdução A reabilitação oral de pacientes com atrofia óssea maxilar representa um grande desafio por estes pacientes apresentarem comprometimento da qualidade de vida, dificuldades alimentares, complicações nutricionais, dificuldades sociais e emocionais. Propostas de reabilitações de maxilas mutiladas e/ou atróficas com próteses totais fixas implantossuportadas, utilizando implantes zigomáticos, foram relatadas. Objetivo O objetivo deste estudo foi avaliar o grau de satisfação dos pacientes reabilitados com implantes zigomáticos e convencionais, em função de carga imediata com prótese do tipo protocolo através de um estudo retrospectivo, por meio de questionário respondido pelos pacientes. Material e método Foram incluídos dezenove pacientes, tratados na clínica do Instituto Latino Americano de Pesquisa e Ensino Odontológico (ILAPEO) em Curitiba, PR (Brasil), entre dezembro de 2005 e junho de 2010. Os pacientes foram reabilitados com 41 implantes zigomáticos e 73 implantes convencionais, todos do tipo cone Morse. As próteses, tipo híbridas, foram instaladas em carga imediata. Resultado O índice de satisfação encontrado foi de 100%. Conclusão Pode-se concluir que esta técnica de reabilitação restabelece fatores primordiais ao ser humano como mastigação, fonética e estética. Os pacientes relataram satisfação com o resultado do tratamento, conseguindo desenvolver atividades sociais dentro da normalidade, elevando sua autoestima.

Evaluation of Clinical Soft Tissue Parameters for Extramaxillary Zygomatic Implants and Conventional Implants in All-on-4 Hybrid Rehabilitations: Short-Term Outcome and Proposal of Clinical Recommendations for Intervention in Recall Appointments

PURPOSE

This prospective cohort study aimed to investigate the short-term soft tissue clinical outcomes and recommendation for evaluation and follow-up after a new hybrid All-on-4 rehabilitation.

METHODS

Forty consecutively included patients rehabilitated in the complete edentulous atrophic maxillae through a hybrid All-on-4 treatment concept (4 immediate function implants in a combination between zygomatic and conventional implants). Periimplant conditions at zygomatic and conventional implants were compared. Four clinical levels (CLs) were used to classify the presence and severity of periimplant conditions.

RESULTS

Four patients withdrew from the study. No significant differences were found for periimplant conditions at zygomatic and conventional implants. The distribution was 28, 2, 1, and 9 patients with CL1, CL2, CL3, and CL4, respectively.

CONCLUSIONS

Soft tissue clinical outcomes of extramaxillary zygomatic implants and conventional implants seem to follow a similar distribution. The proposed classification system stratifies patients, supports decision making, and with further validation may elucidate recommendations for frequency of recall appointments and intervention to enhance long-term success.

Simplifying the Treatment of Bone Atrophy in the Posterior Regions: Combination of Zygomatic and Wide-Short Implants-A Case Report with 2 Years of Follow-Up

The rehabilitation of maxillary and mandibular bone atrophy represents one of the main challenges of modern oral implantology because it requires a variety of procedures, which not only differ technically, but also differ in their results. In the face of limitations such as deficiencies in the height and thickness of the alveolar structure, prosthetic rehabilitation has sought to avoid large bone reconstruction through bone grafting; this clinical behavior has become a treatment system based on evidence from clinical scientific research. In the treatment of atrophic maxilla, the use of zygomatic implants has been safely applied as a result of extreme technical rigor and mastery of this surgical skill. For cases of posterior mandibular atrophy, short implants with a large diameter and a combination of short and long implants have been recommended to improve biomechanical resistance. These surgical alternatives have demonstrated a success rate similar to that of oral rehabilitation with the placing of conventional implants, allowing the adoption of immediate loading protocol, a decrease in morbidity, simplification and speed of the treatment, and cost reduction. This case report presents complete oral rehabilitation in a patient with bilateral bone atrophy in the posterior regions of the maxilla and mandible with the goal of developing and increasing posterior occlusal stability during immediate loading.

Survival and Complications of Zygomatic Implants: An Updated Systematic Review

PURPOSE

To assess the survival rate of zygomatic implants (ZIs) and the prevalence of complications based on previously published studies.

MATERIALS AND METHODS

An electronic search of 3 databases was performed in December 2015 and was supplemented by manual searching. Clinical series of ZIs were included. Interval survival rate and cumulative survival rate (CSR) were calculated. The untransformed proportion of complications (sinusitis, soft tissue infection, paresthesia, oroantral fistulas) was calculated by considering the prevalence reported in the studies.

RESULTS

Sixty-eight studies were included, comprising 4,556 ZIs in 2,161 patients with 103 failures. The 12-year CSR was 95.21%. Most failures were detected within the 6-month postsurgical period. Studies (n = 26) that exclusively evaluated immediate loading showed a statistically lower ZI failure rate than studies (n = 34) evaluating delayed loading protocols (P = .003). Studies (n = 5) evaluating ZIs for the rehabilitation of patients after maxillary resections presented lower survival rates. The probability of presenting postoperative complications with ZIs was as follows: sinusitis, 2.4% (95% confidence interval [CI], 1.8-3.0); soft tissue infection, 2.0% (95% CI, 1.2-2.8); paresthesia, 1.0% (95% CI, 0.5-1.4); and oroantral fistulas, 0.4% (95% CI, 0.1-0.6). However, these numbers might be underestimated, because many studies failed to mention the prevalence of these complications.

CONCLUSION

ZIs present a high 12-year CSR, with most failures occurring at the early stages postoperatively. The main observed complication related to ZIs was sinusitis, which can appear several years after ZI installation surgery.

Influence of the prosthetic arm length (palatal position) of zygomatic implants upon patient satisfaction

Background

To assess the influence of the prosthetic arm length (palatal position) of zygomatic implants upon patient comfort and stability, speech, functionality and overall satisfaction.

Material and Methods

A retrospective clinical study was made of patients subjected to rehabilitation of atrophic maxilla with complete maxillary implant-supported fixed prostheses involving a minimum of two zygomatic implants (one on each side) in conjunction with premaxillary implants, and with 12 months of follow-up after implant loading. Subjects used a VAS to score general satisfaction, comfort and stability, speech and functionality, and the results were analyzed in relation to the prosthetic arm length of the zygomatic implants 12 months after prosthetic delivery.

Results

Twenty-two patients participated in the study, receiving 22 prostheses anchored on 148 implants (44 were zygomatic and 94 were conventional implants). The mean right and left prosthetic arm length was 5.9±2.4 mm and 6.1±2.7 mm, respectively, with no statistically significant differences between them (p=0.576). The mean scores referred to comfort/retention, speech, functionality and overall satisfaction were high - no correlation being found between prosthetic arm length and patient satisfaction (p=0.815).

Conclusions

No relationship could be identified between prosthetic arm length (palatal position) and patient satisfaction.

Key words:Zygomatic implants, patient satisfaction, zygomatic prosthesis, prosthetic arm length.

Are Zygomatic Implants Associated With Maxillary Sinusitis?

PURPOSE

The purpose of the present study was to analyze the relation between zygomatic implants and symptomatic and radiologic modifications of the maxillary sinuses.

MATERIALS AND METHODS

A retrospective cohort study of patients who underwent zygomatic implant rehabilitation at the Clinic of Dentistry and Maxillofacial Surgery of the University of Verona from January 2005 through May 2014 was designed. The primary predictor variable was time (pre- vs postoperative). Concerning outcome variables, radiologic findings of thickened mucosa or opacification of the maxillary sinuses were evaluated on computed tomograms using the Lund-Mackay Staging System. Clinical symptoms were evaluated using the Sino-Nasal Outcome Test-20 (SNOT-20). The parameters assessed underwent descriptive statistical analysis.

RESULTS

The sample was composed of 41 patients (mean age, 54 yr; 61% women). Preoperatively, 12% had sinus findings. Postoperatively, 46% had sinus findings (P = .0001 by McNemar paired test). Preoperatively, 12% had a SNOT-20 score higher than 11. Postoperatively, 15% had a SNOT-20 score higher than 11 (P = 1 by McNemar paired test).

CONCLUSIONS

In accordance with data in the literature data, placement of zygomatic implants does not seem to be associated with severe rhinosinusitis complications. However, in a considerable number of patients, asymptomatic radiologic alterations of the paranasal sinuses were observed. Therefore, it is important to plan assessments of the prosthetic and peri-implant components of the procedure and the postoperative homeostasis of the maxillary sinuses.

Maxillary "All-On-Four" treatment using zygomatic implants. A mechanical analysis

OBJECTIVE

Zygomatic implants may be used for dental rehabilitation in atrophic maxillae. The aim of this study was to establish experimentally the areas of stress distribution using 2 kinds of "All-On-Four" maxillary procedures.

STUDY DESIGN

The best position to insert the implants was selected using polyurethane craniomaxillary models and surgical guides were made. Group 1 was designed with two posterior zygomatic implants and two conventional anterior implants, and group 2 with two posterior zygomatic implants and two anterior zygomatic implants. A titanium bar was built to link the 4 implants in both groups. Photoelastic replicas of these models were made and the implants were inserted using the surgical guides. An Instrom 4411 testing machine was used to perform a unilateral compressive loading at the level of the right first molar until 2mm of displacement was obtained.

RESULTS

Group 1 showed a high strain concentration in the right lateral orbital region at the level of the apex of the zygomatic implant. Less strain was noticed at the apical levels of the conventional implants in the anterior sector and of the contralateral zygomatic implant. Group 2 showed high strains in the lateral inferior orbital area. The load was low in the alveolar bone sector.

DISCUSSION

Zygomatic bone and paranasal structures are loaded at high levels when zygomatic implants are used to stabilize a full maxillary prosthodontic rehabilitation on 4 implants. The use of 4 zygomatic implants loads the alveolar bone to a lower extent and seems better suited from a mechanical point of view than the use of 2 zygomatic implants.