Zygomatic implants: indications, techniques and outcomes, and the zygomatic success code

Prosthetic rehabilitation of patients with maxillary oncology defects using zygomatic implants

PURPOSE

Prosthetics for patients after oncological resection of the upper jaw is a complex problem associated with the physiological and anatomical separation of the oral cavity and the nasal/paranasal region. This study reports the clinical results of the use of the zygomatic implants for prosthetic rehabilitation in patients with maxillectomy due to upper jaw tumors.

MATERIALS AND METHODS

The study included 16 patients who underwent prosthetic rehabilitation using a zygomatic implant after maxillectomy period from 2021 to 2023. After the tumor was removed, immediate surgical obturators were placed. Main prosthetic rehabilitation was performed 6-12 months after tumor removal, but before that, a temporary obturator was made and used. Six-twelve months after tumor resection, 1-4 zygomatic implants were inserted into the zygomatic bone unilaterally or bilaterally. A total of 42 zygomatic implants were installed, 2 of which were unsuccessful and were removed in 1 patient. The implants were placed using the surgical guide, which was planned and prepared digitally.

RESULTS

No postsurgical complications were seen, and the patients were discharged from the hospital after 7-10 days. The patients were able to return to a normal diet (hard food) after just 7 days following surgery, with no further complaints regarding function or pain, apart from the residual edema caused by the intervention.

CONCLUSIONS

The use of prostheses fixed on zygomatic implants in patients with maxillary defects is an effective method of prosthodontic rehabilitation in complex clinical cases after maxillectomy.

Effectiveness of zygomatic-implant fixed rehabilitation for the atrophic edentulous maxilla: protocol for a systematic review and network meta-analysis

BACKGROUND

Atrophic edentulous maxilla is a debilitating condition caused by the progressive and irreversible bone resorption following loss of teeth, that results in bone of inadequate volume and density. This makes conventional implant therapy extremely challenging without complex reconstructive procedures. Several techniques such as sinus augmentation, short implants, and tilted implants have been used for the rehabilitation of the atrophic maxilla. In recent years, zygomatic implants have emerged as a graftless rehabilitation technique. However, few studies compare zygomatic-implant fixed rehabilitation with other fixed rehabilitation techniques. The existing body of evidence on zygomatic implants is largely based on clinical and disease-oriented outcomes.

METHODS

A network meta-analysis (NMA) will be conducted in order to compare the effectiveness of zygomatic-implant fixed rehabilitation with the other rehabilitation techniques. Experimental and observational studies comparing different implant-assisted fixed rehabilitation in adults with atrophic maxilla will be included. The primary and secondary outcomes will be patient's satisfaction and quality of life respectively. Additional outcomes include the implant's survival/success, and biological and prosthetic complications. An electronic search will be performed through various databases for articles in English and French, without time limits. Risk of bias will be assessed using the Revised Cochrane Risk-of-Bias tool for randomized controlled trials, and ROBINS-I for non-randomized and observational studies. Two independent reviewers will screen the titles and abstracts and extract data. Any discrepancy between reviewers will be discussed and resolved through consensus or with the help of a third reviewer. Pairwise meta-analyses will be performed using a random effects model. I2, τ2, transitivity, subgroup/meta-regression analyses will assess and explain heterogeneity and distribution of effect modifiers. A network plot will be created to connect the different interventions directly and indirectly. Interventions will be ranked using the surface under cumulative ranking curve. Confidence in the results of the NMA will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

DISCUSSION

This study will be the first to assess the effectiveness of zygomatic-implant fixed rehabilitation for the atrophic maxilla using NMA. The evidence obtained will aid clinical decision-making and will advance the knowledge of the rehabilitation techniques for the atrophic maxilla.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023353303.

Zygomatic Implant-Supported Prosthetic Rehabilitation of a Patient with Post-COVID-19 Mucormycosis and Maxillectomy

Mucormycosis has been prevalent in the past few years with the COVID-19 pandemic largely affecting the maxilla due to its proximity to the respiratory corridor. Resection of the maxillary dentition along with the maxillary bone itself has a huge psychosocial impact on the patient. When seeking prosthetic rehabilitation, poor esthetics, difficulty in mastication, and social embarrassment are the patients' concerns. Hence, it becomes great responsibility for the clinician to restore the patient's natural teeth while causing him/her minimum discomfort. This article describes such a case of post-COVID-19 mucormycosis that has been provisionally restored by the means of all-on-four zygomatic implants.

Prosthetic Nasal Reconstruction

Prosthetic nasal reconstruction provides a restorative option for patients with nasal defects, and these can be retained with a variety of methods including adhesives and implants. These prostheses can significantly improve appearance, self-esteem, and quality of life for patients and they restore many functions of the external nose. Traditional fabrication methods are often used by the skilled professionals who make these custom prostheses, but digital technology is improving the workflow for design and fabrication of silicone nasal prostheses. Nasal prosthetic reconstruction requires multidisciplinary coordination between surgeons, maxillofacial prosthodontists, anaplastologists, and other members of the healthcare team. Prosthetic treatment can be considered as an alternative to, or an addition to treatment with surgical reconstruction.

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.

How Can Imbalance in Oral Microbiota and Immune Response Lead to Dental Implant Problems?

Dental implantology is one of the most dynamically developing fields of dentistry, which, despite developing clinical knowledge and new technologies, is still associated with many complications that may lead to the loss of the implant or the development of the disease, including peri-implantitis. One of the reasons for this condition may be the fact that dental implants cannot yield a proper osseointegration process due to the development of oral microbiota dysbiosis and the accompanying inflammation caused by immunological imbalance. This study aims to present current knowledge as to the impact of oral microflora dysbiosis and deregulation of the immune system on the course of failures observed in dental implantology. Evidence points to a strong correlation between these biological disturbances and implant complications, often stemming from improper osseointegration, pathogenic biofilms on implants, as well as an exacerbated inflammatory response. Technological enhancements in implant design may mitigate pathogen colonization and inflammation, underscoring implant success rates.

Periantral fungal abscess after zygoma reduction: a case report

This case report describes our treatment of a persistent periantral abscess in a 35-year-old woman. The abscess developed following a zygoma-reduction surgery, during which a preexisting fungal ball had not been addressed. Our comprehensive treatment approach included functional endoscopic sinus surgery, fungal ball removal, abscess drainage, and debridement. Two weeks postoperatively, the patient's symptoms had resolved. A 6-month postoperative follow-up revealed no signs of recurrence or complications, and the patient reported satisfactory functional and aesthetic results. This case underscores the importance of thorough preoperative evaluations and raises awareness about the potential risks of untreated asymptomatic pathologies, which can potentially progress and lead to further complications.

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.

Feasibility and accuracy of a task-autonomous robot for zygomatic implant placement

STATEMENT OF PROBLEM

Zygomatic implants (ZIs) should be placed accurately as planned preoperatively to minimize complications and maximize the use of the remaining bone. Current digital techniques such as static guides and dynamic navigation are affected by human error; therefore, new techniques are required to improve the accuracy of ZI placement.

PURPOSE

The purpose of this clinical study was to assess the feasibility and accuracy of a task-autonomous robot for ZI placement.

MATERIAL AND METHODS

Patients indicated for ZI placement were enrolled, and an appropriate surgical positioning piece was selected based on the presence of natural teeth in the maxilla. Preoperative cone beam computed tomography (CBCT) scanning was performed with the surgical positioning piece, and virtual implant design and socket preparation procedures were initiated. Implant socket preparation and placement were automatically performed by the robot according to the preoperative plan under the supervision of the surgeon. Postoperative CBCT scanning was performed to evaluate deviations between the virtual and actual implants. All quantitative data were expressed as standardized descriptive statistics (mean, standard deviation, minimum, maximum, and 95% confidence interval [CI]). The Shapiro-Wilk test was used to assess the normal distribution of all variables (α=.05).

RESULTS

Six participants were enrolled, and 8 ZIs were inserted. No intraoperative or postoperative complications were observed. Robotic ZI placement showed a global coronal deviation of 0.97 mm (95% CI: 0.55 to 1.39 mm), a global apical deviation of 1.27 mm (95% CI: 0.71 to 1.83 mm), and an angular deviation of 1.48 degrees (95% CI: 0.97 to 2.00 degrees).

CONCLUSIONS

Task-autonomous robots can be used for ZI placement with satisfactory accuracy. Robotic ZI surgery can be an alternative to static guidance and dynamic navigation to improve the accuracy of implant placement.

The Zygomatic Anatomy-Guided Approach, Zygomatic Orbital Floor Classification, and ORIS Criteria-A 10-Year Follow-Up

BACKGROUND

Presently, the management of patients with maxilla bone defects of the Cawood V or VI class is achieved using zygomatic or individual implants or through augmentation of the bone. For zygomatic implants, the ORIS criteria represent the most common factor in helping practitioners register success rates. The zygomatic anatomy-guided approach (ZAGA)and zygomatic orbital floor (ZOF) are factors that are crucial to examining the anatomy of a particular patient before the procedure. The aim of thisarticle is to find the statistical relationship between the abovementioned terms and other factors.

METHODS

A total of 81 patients underwent zygomatic implant procedures in different configurations. The ORIS, ZAGA, and ZOF parameters were compared with other factors such as type of surgery, sex, age, and the anatomy of the zygomatic bone.

RESULTS

Most patients in this article were classified as ZAGA Class 2. The relationships between type of surgery and ZAGA classification, and ZAGA and sinus/maxilla zygomatic implant localization were statistically significant.

CONCLUSIONS

The ZAGA and ZOF scales are practical and valuable factors that should be taken into account before surgery, whereas to date, criteria better than the ORIS scale have not been described in terms of the success of zygomatic implants. The ZOF scale might omit perforation of the orbit because this parameter warns a practitioner to be aware of the anatomy of the orbit.

Rehabilitation of the severely resorbed maxilla by using quad zygomatic implant-supported prostheses: a systematic review and meta-analysis

STATEMENT OF PROBLEM

Quad zygomatic implants have been used as a treatment option for patients with a severely resorbed maxilla. However, data on the average rate of success of the prosthesis, survival of the zygomatic implants, and associated complications are sparse.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess prosthetic and zygomatic implant success of treating severe maxillary resorption with prostheses supported by 4 zygomatic implants, with an additional review on potential complications.

MATERIAL AND METHODS

A comprehensive search of studies published in English between January 2001 and December 2020 was performed in the PubMed, OVID, EBSCO, and EMBASE databases according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42021219468). The population, intervention, comparison, and outcome (PICO) question was "What is the effectiveness of oral rehabilitations using only 4 zygomatic implants placed in severely resorbed maxillae?" The search results were subjected to a systematic review for articles reporting prosthetic success and zygomatic implant survival. Prosthetic success was analyzed by using a fixed-effects inverse-variance model. The random-effects model was adopted for meta-analysis as moderate heterogeneity was identified among studies that reported implant survival in quad zygoma treatments. The quality of publications was appraised by using the Critical Appraisal Skills Program (CASP) checklists.

RESULTS

Of the 82 titles, 7 studies that met the inclusion criteria without an overlap of patient cohorts were quantitatively analyzed for the average rate of prosthetic success and implant survival. All prostheses in the aggregated studies were immediately loaded with acrylic resin interim prostheses replaced by a definitive prosthesis, which consisted of overdentures retained by bar splinting (n=2), metal bar-reinforced prostheses (n=2), fixed screw-retained acrylic resin prostheses (n=34), and screw-retained titanium prostheses with ceramic or acrylic resin teeth (n=75). Technical complications of zygomatic implants included mobility associated with a machined surface and fracture of the abutment screw. The most common prosthetic complications reported were fracture of the definitive prosthesis and loss of the interim prosthesis subsequent to the failure of at least 1 zygomatic implant. The results showed that prostheses supported by quad zygoma implants displayed an overall success of 100% (CI=95%, I2=0.00%, P=.850), whereas zygomatic implants showed a survival rate of 98% (CI=95%, I2=60.48%, P=.040) with minimal implant failures and few complications.

CONCLUSIONS

Although the data analysis showed favorable results for rehabilitating severely resorbed maxillae by using quad zygoma with high prosthetic success and high implant survival rate, further long-term clinical studies are required to strengthen the evidence. However, potential implant and prosthetic complications should be considered while planning this treatment approach.

Five Steps for the Maintenance and Interception of Complications in Zygomatic Implants

Zygomatic implants are used for the rehabilitation of the upper jaw of patients with severe and moderate bone atrophy. Possible post-surgical complications include soft tissue dehiscence, sinusitis, and prosthodontic fractures, and maintaining an accurate control is crucial. Additionally, zygomatic implants have a unique peri-implant anatomy, making traditional periodontal parameters unsuitable. The present paper aims to provide guidelines for the maintenance and interception of complications in patients rehabilitated with these kinds of implants. The proposed protocol includes: 1. intra/extraoral and temporo-mandibular joint examination; 2. soft tissue and transmucosal path observation with magnifiers; 3. peri-implant health indices and digital stimulation of tissues; 4. examination of prosthodontic devices; and 5. photographic recording. These steps facilitate the comprehensive evaluation and monitoring of clinical conditions of zygomatic-supported rehabilitations, including dehiscence and occlusal wear during follow-up appointments.

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.

Cost-effectiveness of the Flapless Insertion of Zygomatic Implants Using Dynamic Navigation - A Retrospective Study

Introduction

Zygomatic implants are an effective solution for rehabilitation of edentulous atrophic maxillae. However, the conventional technique of zygomatic implant placement is invasive, requires a longer healing period and is economically cumbersome. Therefore, the flapless technique of insertion of zygomatic implants using dynamic navigation system has been introduced. This study aims to compare the cost-effectiveness of flapless insertion of zygomatic implants using dynamic navigation to the conventional flap technique.

Materials and Methods

The study participants were divided into two groups: Group A (n = 20) included patients treated by flapless insertion of zygomatic implants using dynamic navigation and Group B (n = 20) included patients treated with zygomatic implants using the flap technique. An analysis of the effectiveness of the implants was done using the concept of quality-adjusted prosthesis years, and an analysis of the costs was done by evaluating the treatment costs at each step. The data were collected, and analysis was done using IBM SPSS software. The Kruskal-Wallis rank-sum test was employed to analyse variations in costs and effects between the two groups.

Results

The study showed that the distribution of costs varies across both the categories of the procedure. Group B shows lesser cost-effectiveness as compared to Group A.

Conclusion

The technique of flapless insertion of zygomatic implants is cost-effective. However, further studies considering factors such as time and cost of productivity evaluating the cost-effectiveness should be conducted.

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.

Success Rates of Zygomatic Implants for the Rehabilitation of Severely Atrophic Maxilla: A Systematic Review

Zygomatic implants are a treatment solution for patients with severe maxillary atrophy. This treatment option allows delivering immediate fixed teeth within 24 h. Numerous peer-reviewed publications have reported different success rates, resulting in a disagreement on the topic. Therefore, the overall efficacy and predictability of this rehabilitation is still a matter of discussion. With this study, we aimed to identify the published literature on the use of zygomatic implants for the reconstruction of the severely atrophic maxilla and report the cumulative success rate (CSR) as a function of follow-up time. A systematic review of the literature on zygomatic implant for the treatment of severe maxillary atrophy was performed and 196 publications were included in the study. The cumulative success rate of zygomatic implants for the treatment of severe maxillary atrophy was 98.5% at less than 1 year, 97.5% between 1 and 3 years, 96.8% between 3 and 5 years and 96.1% after more than 5 years. The most commonly reported complications were soft tissue dehiscence, rhinosinusitis and prosthetic failures. The treatment of severe lack of bone in the upper maxilla with zygomatic implants is a safe procedure, reaching a cumulative success rate of 96.1% after more than 5 years.

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.

Fixture Length and Primary Stability: An In Vitro Study on Polyurethane Foam

(1) Background: Recently, novel dental implants that are characterized by different levels of surface roughness in the distinct parts of the fixture’s body have been introduced in the market. These surface characteristics could affect the primary stability of the implants. The aim of this in vitro study was to compare the primary stability of short and long implants, characterized by multiscale surface roughness, inserted on polyurethane blocks. The secondary aim was to understand if the implant length could be a crucial factor in the decision-making in immediate or rather than delayed loading protocol in the different bone densities. (2) Methods: A total of 20 cylindrical dental implants with a diameter of 5.0 mm were tested for the lengths 6.0 mm (short implants) versus 13.0 mm (long implants) on two different solid rigid polyurethane blocks (20 and 30 PCF). The primary stability was evaluated by measuring the insertion torque value (ITV), the removal torque (RTV), and the resonance frequency analysis RFA. (3) Results: The values of ITV, RTV, and RFA showed the same trend in all measurements. Long implants showed a significantly higher primary stability on 30 PCF blocks that present mechanical properties similar to high-density bone. On the contrary, no relevant differences were found on 20 PCF blocks, which mimic trabecular bone density. (4) Conclusions: The impact of fixture length on the primary stability of implants with multiscale surface roughness is significant in 30 PCF polyurethane corresponding to higher bone density, but not in lower ones.

Reliability and accuracy of dynamic navigation for zygomatic implant placement

Objectives

To assess the accuracy of a real‐time dynamic navigation system applied in zygomatic implant (ZI) surgery and summarize device‐related negative events and their management.

Material and methods

Patients who presented with severely maxillary atrophy or maxillary defects and received dynamic navigation‐supported ZI surgery were included. The deviations of entry, exit, and angle were measured after image data fusion. A linear mixed‐effects model was used. Statistical significance was defined as p < .05. Device‐related negative events and their management were also recorded and analyzed.

Results

Two hundred and thirty‐one zygomatic implants (ZIs) with navigation‐guided placement were planned in 74 consecutive patients between Jan 2015 and Aug 2020. Among them, 71 patients with 221 ZIs received navigation‐guided surgery finally. The deviations in entry, exit, and angle were 1.57 ± 0.71 mm, 2.1 ± 0.94 mm and 2.68 ± 1.25 degrees, respectively. Significant differences were found in entry and exit deviation according to the number of ZIs in the zygomata (p = .03 and .00, respectively). Patients with atrophic maxillary or maxillary defects showed a significant difference in exit deviation (p = .01). A total of 28 device‐related negative events occurred, and one resulted in 2 ZI failures due to implant malposition. The overall survival rate of ZIs was 98.64%, and the mean follow‐up time was 24.11 months (Standard Deviation [SD]: 12.62).

Conclusions

The navigation‐supported ZI implantation is an accurate and reliable surgical approach. However, relevant technical negative events in the navigation process are worthy of attention.

Rehabilitation of the Completely Edentulous Mandible by All-on-Four Treatment Concept: A Retrospective Cohort Study with Up to 10 Years Follow-Up

(1) Background and Objectives. Currently, there are no definitive long-term data about clinically significant difference in the failure of prosthesis and implant or marginal bone loss related to the rehabilitation of the completely edentulous mandible by all-on-four treatment concept. The main aim of present investigation was to report the long-term outcomes (10-years follow-up) of complete-arch mandibular rehabilitations based on the all-on-four concept. (2) Materials and Methods. Patients in need of extractions of teeth due to the occurrence of caries and/or severe periodontal disease and patients presented with edentulous mandibles were enrolled to the study. A total of 96 participants (mean follow-up period after intervention of 3185.2 days) were enrolled in the study. Participants were evaluated at the first visit, 10 days after intervention and every year after the intervention. Implant and prosthesis survival, bone loss and both local biological and mechanical complications were evaluated during the follow-up period. (3) Results. An implants’ survival rate of 97.9% was observed at the end of the follow-up period. Biological complications were reported in 19.8% of patients, whereas mechanical complications were reported in 27.1% of cases. The average marginal bone level at baseline was −0.03 mm. A significant marginal bone loss was observed after 10-years follow-up (2.5 mm). Binary logistic regression analysis showed significant association between smoke and both marginal bone loss and local biological complications. Lastly, a significant association was observed between bruxism and mechanical complications. (4) Conclusions. The high implant and prosthesis survival rate and the moderate incidence of biological and mechanical complications observed in present investigation can be associated to several factors such as high implant primary stability, prosthetic design, and control of the occlusal forces.

Simultaneous Le Fort I osteotomy and zygomatic implant placement

The aim of this retrospective study was to evaluate the outcomes of simultaneous LeFort I osteotomy and zygomatic/dental implant placement for oral rehabilitation of patients with extremely atrophic/dysmorphic edentulous maxilla. Simultaneous LeFort I osteotomy and zygomatic/dental implant placement was performed with patient-specific anatomical models and surgical guides produced through three-dimensional virtual planning methods. All patients received their final prosthesis, with immediate loading, on the day after surgery. The primary outcome variables were the implant survival rate, and the incidence of intra/postoperative complications. In total, 15 zygomatic implants and 33 conventional dental implants were inserted in eight patients. The mean follow-up of the patients was 38.5 months. The implant survival rate was 93.3% for zygomatic implants and 100% for dental implants. No intra/postoperative complications were observed. Simultaneous LeFort I osteotomy associated with zygomatic/dental implant surgery can be considered as a valuable treatment option for rehabilitation of patients with extremely atrophic edentulous maxilla and esthetic issues of the face.

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.

Attitudes regarding zygomatic implant surgical and prosthodontic techniques-a cohort questionnaire study

BACKGROUND

Zygomatic implant (ZI) surgery and restoration is a complex procedure, requiring experienced clinicians to execute with success. This study assessed the opinion and clinical experiences of a cohort of practitioners involved in provision of zygomatic implant treatment on aspects of the surgical and prosthodontic procedures.

METHOD

A survey was distributed among all 176 delegates attending 'Zygomatic 2019' International Conference in the UK, and all delegates completed the survey.

RESULTS

The respondents were clinicians from both prosthodontic and surgical specialties, with a range of experience. Strong agreements were found regarding the use of specific implant designs dependent on the anatomical situation, and that fixed restorations should be used where possible. There was limited agreement between respondents regarding surgical approaches to ZI treatment.

CONCLUSION

The limited agreement found between respondents highlights the varied and conflicting literature available on ZI surgery. High-quality research is required to inform clinicians and assist education.

Tilted versus axial implant distribution in the posterior edentulous maxilla: A CBCT analysis

OBJECTIVES

This study aimed to determine whether distally angulating an implant is a successful strategy to avoid the maxillary sinus and the need for bone augmentation, while increasing the anterior-posterior (A-P) implant distribution in the edentulous maxilla.

MATERIALS AND METHODS

In 115 patients with edentulous maxillae, virtual implant planning was performed utilizing cone-beam computer tomographs. Axial (8 mm length) and tilted (12 mm length) dental implants with 30-degree and 45-degree angulation were virtually positioned to avoid entering the maxillary sinus, while maximizing A-P distribution. Measurements were made between the tilted and axial implants to assess the change in A-P distribution of implants at the implant and abutment levels.

RESULTS

Forty-seven sites (20.4%) were not able to have either treatment modality with insufficient bone for implant placement. Axial implants were placed more distally than 45-degree and 30-degree tilted implants in 24% and 42% of sites, respectively. The average change in A-P spread measured at the implant level, for 30- and 45-degree tilted implants was -0.25 mm (95% CI -0.76, 0.26) and 1.9 mm (95% CI 1.4, 2.3), respectively. When measured from the center of each multi-unit abutment the average increase in A-P distances for tilted implants appears larger in the 30-degree and 45-degree groups by 0.97 mm and 1.74 mm, respectively compared to measurements at the implant level.

CONCLUSIONS

Angulating 12 mm implants provides a limited increase in A-P distribution of implants in edentulous rehabilitation in most situations. In certain patients, the use of 8mm axial implants may provide a greater A-P spread.

Extra-long transnasal implants as alternative for Quad Zygoma: Case report

Introduction and importance

The aim of this case report is to present a technical report for rehabilitation of patients with atrophic maxilla with the use of extra-long transnasal implants associated with unilateral zygomatic implants.

Case presentation

The indications, contraindications, planning and surgical procedure are described in order to give surgeons confidence in the management of this surgical approach to how to increase the range of rehabilitative options available to surgeons and patients.

Clinical discussion

Maxillary bone atrophy is a challenge demanding a high degree of experience of dental surgeons who trains themselves to rehabilitate these patients, whose treatment options range from bone grafts through to zygomatic implants. Extensive regions of atrophy require the use of 4 zygomatic implants which, in spite of offering predictability of the treatment, increase the surgical risk, require zygomatic bone with volume for anchoring 2 zygomatic implants. Generally, this bone density is reduced in elderly patients, making apical anchorage of the implants unfeasible.

Conclusion

The case report presented is a feasible alternative for replacing the placement of a second zygomatic implant, thereby diminishing the surgical risk, and making it possible for the technique to be more extensively used and performed by a larger number of surgeons.

•

Present a case report with the use of extra-long transnasal implants.

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Alternative for substituting the insertion of a second zygomatic implant.

•

Decrease the surgical risk.

A practical approach to orofacial rehabilitation in a patient after inferior maxillectomy and rhinectomy with mono framework construction supported on a zygomatic implant placed in the glabella: a case report

Background

In the field of craniofacial tumor surgery, an adequately performed excision, despite being a life-saving procedure, is only a first step to successful treatment. During such a procedure, the main goal is to completely remove the lesion, paying less attention to factors contributing to future rehabilitation possibilities. One ty 2of the possibilities for prosthetic rehabilitation of such cases is utilizing one-piece implants with bicortical anchorage.

Case presentation

This case report presents a case of a 48-year-old patient with oral squamous cell carcinoma (OSCC). The treatment protocol consisted of radical surgery to remove the tumor, and intraoral and extraoral rehabilitation with a single framework prosthesis anchored with one-piece implants. Moreover, the intraoral stomatognathic deformity was corrected with a fixed implant-retained prosthesis, and the extraoral defect was covered with a removable epithesis.

Conclusions

The use of one-piece implants with bicortical anchorage may be an additional tool in reconstructing maxillofacial defects. Properly executed treatment may improve the esthetics, speech, masticatory function, muscle support, and the overall quality of life of patients with extensive defects in the maxillofacial region.

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.

Clinical outcomes and biological and mechanical complications of immediate fixed prostheses supported by zygomatic implants: A retrospective analysis from a prospective clinical study with up to 11 years of follow-up

BACKGROUND

Zygomatic implants alone or in combination with conventional implants have been used for severe atrophic maxillary arches. Long-term outcomes of extramaxillary technique need validations.

PURPOSE

To retrospectively assess the clinical outcomes and the prevalence of surgical, biological, and prosthetic complications of implant-fixed complete dental prostheses (IFCDPs) supported by zygomatic implants up to 11 years of follow-up.

MATERIALS AND METHODS

Dental records of 34 subjects treated between October 2008 and June 2019 were reviewed. Patients received an immediate fixed full-arch prosthesis supported solely by zygomatic implants or by a combination of zygomatic and conventional implants.

RESULTS

A total of 90 zygomatic implants and 53 standard implants were placed. Up to 11 years of follow-up, two conventional implants were lost, leading to 96.2% success rate for conventional implants and 100% for zygomatic implants. Marginal bone loss for conventional implants averaged 0.85 ± 0.17 mm after the first year and 1.36 ± 0.12 mm after 10 years, resulting in full implant success. No prosthesis was lost. The main surgical complication was the perforations of the Schneiderian membrane, occurring in five patients and in seven sinus cavities. Considering the biological complications, mucositis for standard and zygomatic implants ranged between 21%-35% and 26%-40%, respectively. No peri-implantitis were reported. Soft tissue hypertrophy ranged between 1.8% and 30% for conventional implants and 1.1%-35% for zygomatic implants. Inflammation under the prosthesis ranged between 33% and 50%. For the mechanical complications, abutment loosening was recorded in 5.8% of cases (two patients), tooth debonding and fracture of the prosthesis happened in five subjects (14.7%), and loosening of the prosthetic screws was reported in one patient (2.9%).

CONCLUSIONS

Immediate rehabilitation of the severely atrophic maxilla with zygomatic implants alone or in combination with standard implants could be considered a viable treatment modality.

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.

Patient-reported outcomes and complication rates after lateral maxillary sinus floor elevation: a prospective study

Objectives

Oral surgery morbidity is highly variable based on patients’ characteristics and kind of surgical intervention. However, poor data are available in the literature regarding patient outcomes after oral surgery. The aim of this retrospective study was to evaluate patient-reported outcome and complication rates after maxillary sinus floor elevation.

Materials and methods

Data from the records of patients undergoing maxillary sinus elevation have been collected from a private dental office. Patient-reported outcome has been assessed using a 100-mm visual analog scale to evaluate the post-operative pain (VAS_pain) experienced in the first week following surgery and visual rating scales to evaluate discomfort level (VRS_discomfort: 0 to 4) and willingness to repeat the same surgical procedure (VRS_willingness: 0 to 3). Analgesics intake, swelling onset and duration, and ecchymosis have been also recorded.

Results

VAS_pain showed moderate values in the first 2 days (< 50) post-surgery, with a tendency to progressively decrease over the next 2 days. Average assumption of painkillers was 3.93 ± 3.03. Discomfort level (VRS_discomfort) after surgery was low (median: 1; IR: 1–0), while willingness to undergo the same surgical procedure was very high (77.63% of patients). Swelling and ecchymosis were experienced by 97.36% and 51.32% of patients, respectively, with a mean duration of 4.09 ± 1.43 and 2.21 ± 2.31 days, respectively. Membrane perforation occurred in 4 cases. Other post-operative complications were not observed.

Conclusions

Maxillary sinus grafting is a safe procedure, with a low complication rate and moderate morbidity that is well tolerated by patients. Particular attention is needed in case selection, surgical planning and operator expertise.

Clinical relevance

The analysis of patient-reported outcomes can be of great help in surgical planning and in providing correct and adequate treatment.

Three-dimensional measurement of radiographic bone-implant contact lengths of zygomatic implants in zygomatic bone: a retrospective study of 66 implants in 28 patients

Zygomatic implant treatment is widely applied for severe maxillary atrophy to help rehabilitate the maxillary dentition. This retrospective study was performed to evaluate the actual radiographic bone-implant contact (rBIC) lengths of zygomatic implants. The records of 28 patients who underwent zygomatic implant surgery and subsequent follow-up examinations between August 2013 and September 2018 in the Department of Oral and Maxillofacial Surgery, Taipei Tzu Chi Hospital were reviewed. The surgeries were performed by a single surgeon using the same treatment protocol. All patients had a computed tomography scan at 1year after the surgery. Using three-dimensional imaging software, an investigator measured the rBIC lengths of 66 implants and documented their clinical status. The implant survival rate was 100%. The mean rBIC length was significantly longer in male patients than in female patients (20.80±5.88mm versus 17.79±6.34mm; P=0.028). The mean rBIC length of double zygomatic implants was significantly longer when compared to that of single implants (21.11±6.23mm versus 17.75±5.85mm; P=0.027). This article is novel in reporting the exact rBIC lengths of zygomatic implants in a clinical setting. The results showed that zygomatic implants are a viable treatment modality for full-mouth rehabilitation.

Zygomatic implant-supported prosthodontic rehabilitation of edentulous patients with a history of cleft palate: A clinical report

Zygomatic implants are an established treatment option in the management of the atrophic maxilla and in oncology rehabilitation, but evidence for their use in patients with a history of cleft palate is sparse. Zygomatic implants were used to retain a maxillary prosthesis in 7 edentulous patients with an unrepaired or repaired cleft lip and palate. Patient records were reviewed retrospectively to assess the survival rates. The mean follow-up time was 5 years with an implant survival of 100%. Most complications were associated with the prosthetic superstructures. This clinical report demonstrates that zygomatic implants can be successfully used to provide a maxillary prosthesis in patients with a history of cleft palate.

Zygomatic implants placed in atrophic maxilla: an overview of current systematic reviews and meta-analysis

BACKGROUND

Zygomatic implants are a treatment option for severely atrophic maxilla.

MAIN TEXT

This study aimed to summarize and evaluate systematic reviews assessing the clinical outcomes of zygomatic implants including survival/failure rate and complications. PubMed-MEDLINE, Google Scholar, LILACS, and the Cochrane Database were searched up to April 2020. Risk of bias assessment was conducted by the AMSTAR tool. Initial searches yielded 175 studies. These were assessed, and following title abstract and full-text evaluation, 7 studies (2 meta-analyses) were included in the final review. According to the AMSTAR tool, 1 was deemed high quality, 4 were classified as medium, and 2 as low quality. The mean AMSTAR score (±SD) was 5.28 of 9 (±2.36) ranging from 2/9 to 9/9. The reported survival rates ranged from 95.2 to 100% except for resected maxillas, which established higher failure rates up to 21.43%. Concerning the complications with the zygomatic implants, various surgical and prosthetic complications were reported with sinusitis being the most frequently observed complication. Zygomatic implants appears to offer a promising alternative to formal bone grafting techniques with lower costs, less complications, less morbidity, shorter treatment times, and comparably high survival rates.

CONCLUSION

Complications were rare and usually easy to manage. However, the treatment should be directed by appropriately trained clinicians with noticeable surgical experience.

Comparative accuracy of cone-beam CT and conventional multislice computed tomography for real-time navigation in zygomatic implant surgery

BACKGROUND

Cone-beam computed tomography (CBCT) and conventional multislice CT (MSCT) are both used in zygomatic implant navigation surgery but the superiority of one technique versus the other remains unclear.

PURPOSE

This study compared the accuracy of CBCT and MSCT in zygomatic implant navigation surgery by calculating the deviations of implants.

MATERIAL AND METHODS

Patients with severely atrophic maxillae were classified into two groups according to the use of CBCT- or MSCT-guided navigation system. The entry and apical distance deviation, and the angle deviation of zygomatic implants were measured on fused operation images. A linear effect model was used for analysis, with statistical significance set at P < .05.

RESULTS

A total of 72 zygomatic implants were inserted as planned in 23 patients. The comparison of deviations in CBCT and MSCT groups showed a mean (± SD) entry deviation of 1.69 ± 0.59 mm vs 2.04 ± 0.78 mm (P = .146), apical deviation of 2 ± 0.68 mm vs 2.55 ± 0.85 (P < .001), and angle deviation of 2.32 ± 1.02° vs 3.23 ± 1.21° (P = .038).

CONCLUSION

Real-time zygomatic implant navigation surgery with CBCT may result in higher values for accuracy than MSCT.

Three-Dimensional Radiographic Evaluation of the Malar Bone Engagement Available for Ideal Zygomatic Implant Placement

Zygomatic implant rehabilitation is a challenging procedure that requires an accurate prosthetic and implant plan. The aim of this study was to evaluate the malar bone available for three-dimensional zygomatic implant placement on the possible trajectories exhibiting optimal occlusal emergence. After a preliminary analysis on 30 computed tomography (CT) scans of dentate patients to identify the ideal implant emergencies, we used 80 CT scans of edentulous patients to create two sagittal planes representing the possible trajectories of the anterior and posterior zygomatic implants. These planes were rotated clockwise on the ideal emergence points and three different hypothetical implant trajectories per zygoma were drawn for each slice. Then, the engageable malar bone and intra- and extra-sinus paths were measured. It was possible to identify the ideal implant emergences via anatomical landmarks with a high predictability. Significant differences were evident between males and females, between implants featuring anterior and those featuring posterior emergences, and between the different trajectories. The use of internal trajectories provided better bone engagement but required a higher intra-sinus path. A significant association was found between higher intra-sinus paths and lower crestal bone heights.

Quality assessment of systematic reviews regarding the effectiveness of zygomatic implants: an overview of systematic reviews

Background

Oral rehabilitation of atrophic maxillae features high complexity, for which there are several therapeutic modalities reported on scientific literature. Zygomatic implant placement is a viable option that features low morbidity and allows immediate prosthetic loading. The purpose of the present study was to determine the methodological quality of systematic reviews that assessed the effectiveness of zygomatic implants placed in atrophic maxillae.

Material and Methods

Searches were conducted on Medline via Pubmed, LILACS, Dare Cochrane, Scopus, and Sigle via Open Grey up to June 2019.

Results

Seven systematic reviews were eligible for Overview and comprised a total of 2313 patients, 4812 zygomatic implants, and a 96,72% success rate. Common surgical complications, in decreasing order, were: maxillary sinusitis, peri-implant mucositis, prosthetic fracture, and infections. Methodological quality was assessed using the AMSTAR 2 tool, which revealed that six systematic reviews showed critically low methodological quality and one review was assessed as of low methodological quality.

Conclusions

Zygomatic implants seem to be an adequate option for atrophic maxilla rehabilitation, however, new studies with a higher methodological rigor are needed to provide more reliable results to professionals and patients undergoing this modality of oral rehabilitation.

Key words:Zygomatic Implants, dental Implants, complications, oral rehabilitation.

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.

Bone Regeneration and Soft Tissue Enhancement Around Zygomatic Implants: Retrospective Case Series

Purpose: To present a case series of zygomatic implants combined with bone regeneration and soft tissue enhancement techniques to reduce the risk of biological delayed complications such as maxillary sinusitis and soft tissue recession. Materials and methods: Zygomatic implants placed simultaneously with different bone regeneration techniques (buccal, palatal and buccal-palatal bone regeneration) and soft tissue enhancement techniques (pediculate and free connective tissue graft) were followed for at least 12 months. The following information was collected: patient age and sex, number of zygomatic implants, zygomatic implant success rate, zygomatic implant position according to classification of the Zygomatic Anatomy Guide Approach (ZAGA), sinus membrane perforation, type and outcome of the bone regeneration or the soft tissue enhancement technique, bone gain (width and length along the zygomatic implant) and keratinized buccal mucosa width, duration of follow-up, loading protocol (immediate or delayed) and biological complications (maxillary sinusitis and soft tissue recession). Results: Thirty-one zygomatic implants placed in 19 patients were included. All implants were successful and none of the implants presented biological complications. The bone regeneration technique was successful in 30 of 31 cases with a mean palatal bone width of 3 mm, buccal bone width of 2.65 mm, palatal bone length of 6.5 mm and buccal bone length of 8.3 mm. The success rate of soft tissue enhancement was 100% and it established at least 2 mm of keratinized buccal mucosa width in all implants. Conclusions: Within the limitations of the present study, bone regeneration and soft tissue enhancement techniques were useful to establish more favorable conditions of the peri-implant tissues around zygomatic implants. This could prevent biological complications such as maxillary sinusitis and soft tissue recessions. Prospective and randomized controlled clinical trials with longer follow-up periods are advisable.