Zygomatic Implants Research Articles

Real-Time Dynamic Navigation System for the Precise Quad-Zygomatic Implant Placement in a Patient with a Severely Atrophic Maxilla

Zygomatic implants (ZIs) are an ideal way to address cases of a severely atrophic edentulous maxilla and maxilla defects because they replace extensive bone augmentation and shorten the treatment cycle. However, there are risks associated with the placement of ZIs, such as penetration of the orbital cavity or infra-temporal fossa. Furthermore, the placement of multiple ZIs makes this surgery risky and more difficult to perform. Potential intraoperative complications are extremely dangerous and may cause irreparable losses. Here, we describe a practical, feasible, and reproducible protocol for a real-time surgical navigation system for precisely placing quad-zygomatic implants in the severely atrophic maxilla of patients with residual bone that does not meet the requirements of conventional implants. Hundreds of patients have received ZIs at our department based on this protocol. The clinical outcomes have been satisfactory, the intraoperative and postoperative complications have been low, and the accuracy indicated by infusion of the designed image and postoperative three-dimensional image has been high. This method should be utilized during the entire surgical procedure to ensure ZI placement safety.

Double sleeve guided placement of quadruple zygomatic implants for rehabilitation of a patient with ectodermal dysplasia: A clinical report

The surgical and prosthodontic treatment for a 22-year-old man with ectodermal dysplasia is described and illustrated. He had never managed to wear complete dentures, and implant-retained or implant-supported prostheses were indicated. However, the placement of conventional maxillary endosseous implants was contraindicated. A novel surgical template with double sleeves was used to guide osteotomies for 4 zygomatic implants used with an unloaded, one-stage approach. After confirming osseointegration, prosthetic rehabilitation began with an interim implant-supported fixed prosthesis to evaluate esthetics, phonetics, and hygiene maintenance. Clinical challenges included lip biting and speech articulation.

A Modified Zygomatic Implant Placement Technique: A Prospective Study up to 6-year Follow-up

PurposeThis study proposed a new modified technique for zygomatic implant placement and evaluated the up-to-6-year survival rate of endosseous zygomatic implants of the technique and its effects in preventing related complications, such as peri-implantitis, sinusitis, and implant failure. Materials and methodsThis study included 28 patients (15 females, 13 males; mean age: 53.4 years) with a severely atrophic edentulous maxilla (class VI maxillary atrophy, according to the Cawood and Howell classification) combined with a flat buccal sinus wall (zygoma anatomy-guided approach class 0 or 1, according to Aparicio) who received zygomatic implants using the modified technique. There are 3 key points regarding this technique: 1) the zygomatic implant was placed toward the buccal wall of the maxillary sinus, resulting in the implant head being near or on the alveolar crest and allowing less bulky prostheses to facilitate oral hygiene and to prevent soft-tissue infection; 2) autogenous bone block graft material was utilized to reinforce the buccal wall and increase the stability of the implant head; and 3) sinus grafting was performed using a mixture of autogenous particulate bone, bone graft material and platelet-rich fibrin, which created maximum bone coverage around the implant head to consolidate along with the implant. All implant surgeries were carried out under general anesthesia. Implant-supported provisional prostheses were delivered immediately, except in 7 cases in which the zygomatic implant did not achieve initial stability (< 35 N/cm). All patients were scheduled for regular follow-ups every 3 months. Definitive prostheses were provided 6 months after the surgery. ResultsOf the 28 patients treated, a total of 82 zygomatic implants were installed, in conjunction with 52 conventional implants. All of the implants exhibited good osseointegration; in particular, bone coverage was observed around the implant head and the entire length of the implant. Two patients presented complications. One patient exhibited a soft-tissue infection with pus discharge after 1 month of wearing the provisional prosthesis. The other patient exhibited implantitis 4 years after implant placement. Both patients showed buccal bone resorption but no oroantral fistulas, and the sinus membrane remained intact, with no sinusitis. Overall, the survival rate of both the zygomatic and standard implants was 100%. The zygomatic-implant-supported prostheses improved both functional and esthetic aspects for the patients. No cases of sinusitis or soft-tissue inflammation were reported. The mean follow-up period was 35.7 months (range, 0-72 months). ConclusionThis study illustrates that zygomatic implant placement with the new modified technique with the implant head on or near the alveolar bone, onlay bone block augmentation, and extended simultaneous sinus grafting is a successful and important treatment option when rehabilitating the atrophic maxilla. This modified technique yields a high long-term success rate and prevents complications such as peri-implantitis, sinusitis, and implant failure.Intraoral and radiographic images illustrating the procedure A, B, Intraoral images before and after six-month implant placement. C, D, E, F, Intraoral images showed the four zygomatic implants were placed toward the buccal wall of the maxillary sinus resulting in the implant heads were near or on the alveolar crest. Autogenous block bone graft was utilized to reinforce the buccal wall and to increase the stability of the implant head, extended sinus graft was performed to create an maximum bone coverage around implant head to consolidate along the implant. G, H, I, J, K, Radiographic study of the secondary phase of implant placement six months later with bar connecting the four zygomatic implants. G, Orthopantomographic view. H, I, J, K, CT slices showed the osseous integration surrounding all four zygomatic implants.

Oral Rehabilitation of an Adult Cleft Palate Patient with Zygomatic Implant-supported Obturator Prosthesis: A Case Report

IntroductionWith advancement in medical services and their accessibility across the country, as well as growing awareness among the patient population, it is rare to find an adult with an untreated cleft lip and/or palate nowadays. Treatment of these patients to restore form and function can be challenging, often yielding less-than-satisfactory outcomes. In current literature, there have been case reports of patients with atrophic maxilla or severe maxillary defects after oncologic resections, where zygomatic implants have been utilized for fabrication of a fixed maxillary prosthesis.Here, the authors present a case of an adult cleft palate patient treated with a zygomatic implant-supported removable obturator prosthesis, which has not yet been reported in literature. BackgroundThe patient is a 66-year-old female who presented to the University of Maryland Oral & Maxillofacial Surgery Associates in 2016 for management of an untreated bilateral cleft palate. She had been wearing an obturator for several years prior that had slowly lost retention over time due to ridge resorption. Patient had undergone multiple procedures for placement of endosseous implants to support a fixed prosthesis as well as sinus lift surgeries, all of which had failed. She had 1 clinically osseointegrated implant in the right maxilla that was restorable. The patient did not wish to pursue any extensive surgical interventions, so after consultation with a maxillofacial prosthodontist at the authors' unit, the decision was made to pursue a zygomatic implant-supported obturator prosthesis fabrication to restore the patient's form and function. Surgical techniqueThe patient underwent general anesthesia induction and nasotracheal intubation. Mucoperiosteal flaps were reflected bilaterally in the oral cavity along the maxillary alveolar ridge, extending up to orbital rims and laterally over the zygomatic eminence. Sinus windows were created for visualization of twist drills. Osteotomies were created in the zygomatic bone using NobelBiocare protocol, and 2 35mm implants were inserted in the left zygoma, and a 45mm implant was placed on the right-side mesial to the existing endosseous implant. Left maxillary palatal side was grafted with particulate bone, and cover screws were placed. Soft-tissue closure was with 3-0 chromic gut sutures. Implants were buried for 6 months, then uncovered and restored using locator bars to connect implants in each alveolar segments, which would, in turn, support the maxillary obturator. ResultsThe patient has been compliant with follow-ups and last seen in August 2020. She reported good function without any nasal regurgitation and was satisfied with retention and stability of her prosthesis. On examination of her oral cavity after obturator removal, the tissues were healthy-appearing, and the locator housings were evaluated and found to be in good shape and retentive. Radiographically, the implants were stable without signs of bone loss. ConclusionThe authors have found that zygomatic implants can be utilized as an alternative to support an obturator prosthesis. However, given lack of long-term follow-up in literature, some reservations must be expressed in its use, especially when other predictable alternatives are available.

Examination of the stresses of the implants applied to the atrophic edentulous maxilla on the maxillary bone

Aim: In advanced atrophy of the posterior maxilla, applied zygoma implants increase the success of the surgical procedure by reducing morbidity and procedure time. In our study, using tomographic records, a model with posterior atrophy was obtained in a computer environment, and zygomatic and dental implants in different numbers and localizations were applied to this model. The aim of our study was to choose the most accurate surgical planning according to the stresses arising from the applied forces.&#x0D; Methodology: In our study, one zygoma implant on the right and left in Group 1, two zygoma implants in Group 2, one zygoma implant in Group 3 and one dental implant in the first premolar tooth area, one zygoma implant in Group 4 and one dental implant in the lateral tooth area and one zygoma implant in Group 5 and one dental implant in the lateral and a first premolar tooth area were applied. 150 N were applied vertically to the prosthetic superstructure from the lateral tooth, 1st premolar tooth, 1st molar tooth and 2nd molar tooth. As a result of the applied forces, the maximum stress values ​​in the maxilla molar region were examined by finite element stress analysis.&#x0D; Results: In our study, it was observed that Group 1 had the highest stress value, followed by Group 3. Stress values in Groups 2, 4 and 5 were low and they were measured close to each other.&#x0D; Conclusion: As a result of our study, it was seen that zygomatic and dental implants applied in addition to the zygomatic implant reduce stress and the localization of dental implants affect the stress values.&#x0D; &#x0D; How to cite this article: Gülsün B, Çetindağ A. Examination of the stresses of the implants applied to the atrophic edentulous maxilla on the maxillary bone. Int Dent Res 2021;11(Suppl.1):210-5. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.30&#x0D; &#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Prevalence of maxillary sinus alterations after zygomatic surgery. A comparative study between intra-sinus and ZAGA approaches

Zygomatic implant (ZI) is an option of the edentulism. Complications associated with ZI are maxillary sinusitis and soft tissue recession. The Zygoma Anatomy-Guided Approach (ZAGA), reduce the complications of the Original zygomatic intra-sinus Surgical technique (OI-ST). Study Aims: 1) report and compare the prevalence of sinus complications between ZAGA and OI-ST. 2) propose therapeutic guidelines for sinus. Material and Methods: ZAGA has been proposed to reduce the complications of the OI-ST. Results: Statistically significant increase of the "Modified Lund Mackay" (MLM) score (was noted in CT of patients after ZI surgery in comparison with the pre-surgical Lund-Mackay (LM) score (t=5, 0, p&lt;.0005). Our study indicates that patients who underwent the ZI surgery according to the OI-ST. (M = 2.93, SD = 3.65) demonstrated a significantly higher ML-M score (t = 2.99, p &lt; .003) compared to the patients operated with the ZAGA Concept (M = 1.52, SD = 2.36). Conclusions: ZI procedures can lead to sinus alterations. Significant differences have been found between two different approaches.

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

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. 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. 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. 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 ± 6.2months. 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%). 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.

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

Complex reconstructions in the facial and cranial regions

Posttraumatic reconstruction of the neurocranium and viscerocranium is an essential part of modern oral and maxillofacial surgery, in addition to oncological surgery, surgery of congenital craniofacial deformities and dental surgery. Due to the complex anatomy of the facial skull and significant esthetic and functional demands on its reconstruction, reconstructive trauma surgery in this area places the highest demands on the surgeon. This is all the more true if definitive craniomaxillofacial surgical treatment can sometimes only be performed with considerable delays for the benefit of other life-threatening injuries. In order to take these prerequisites into account, achievements of modern biomedical technology, such as intraoperative real-time navigation, computer-assisted planning and computer-assisted manufacturing (CAD/CAM) of patient-specific biomodels and implants, came up early for use in oral and maxillofacial surgery. In combination with intraoperative three-dimensional imaging, these methods result in atreatment pathway tailored to the individual patient, which is directly checked for quality at every step and thus ensures the best possible result for the patient. The use of these technologies extends far beyond the original indications in the area of orbital reconstruction and restoration of bony defects with simple geometry, such as skull defects. Nowadays, even the most complex pan-facial fractures can be restored esthetically and functionally by means of digitalized preliminary planning and individualized skull, orbital and zygomatic implants as well as total temporomandibular joint prostheses.

Zygomatic Implants Placed in Immediate Function through Extra-Maxillary Surgical Technique and 45 to 60 Degrees Angulated Abutments for Full-Arch Rehabilitation of Extremely Atrophic Maxillae: Short-Term Outcome of a Retrospective Cohort.

The use of new devices for the rehabilitation of the severely atrophic maxillae needs validation. We aimed to report the short-term outcome of severely atrophic jaws rehabilitated with zygomatic implants with no implant head angulation placed extramaxillary in conjunction with standard implants. Forty-four patients were consecutively included with 77 zygomatic implants (31 abutments of 45 degrees and 46 abutments of 60 degrees) and 115 standard implants. Outcome measures were prosthetic survival, implant/abutment success, complications, modified plaque index (mPLI), modified bleeding index (mBI), mucosal seal efficacy evaluation (MSEE) >4 mm, and Zygomatic implants classification level (ZICL). Two patients (4.5%) were lost to follow-up. No prosthesis was lost; one patient lost one zygomatic implant; two angulated abutments of 60 degrees needed to be replaced in one patient due to an aesthetic complaint; rendering a cumulative success rate at 2-years of 95.3% and 95.9% using patient and implant/abutment as unit of analysis, respectively. Mechanical and biological complications occurred in 13 and six patients, respectively; all resolved. The median mPLI and mBI was 1; MSEE > 4 mm occurred in 17% and 21% of patients at 1- and 2-years, respectively; ZICL1 was registered in 80% of patients. The current protocol enabled good short-term outcomes.

Biomechanical Stress in Obturator Prostheses: A Systematic Review of Finite Element Studies.

Aim This systematic review is aimed at investigating the biomechanical stress that develops in the maxillofacial prostheses (MFP) and supporting structures and methods to optimize it. Design and Methods. A literature survey was conducted for full-text English articles which used FEA to examine the stress developed in conventional and implant-assisted MFPs from January 2010 to December 2020. Results 87 articles were screened to get an update on the desired information. 74 were excluded based on a complete screening, and finally, 13 articles were recruited for complete reviewing. Discussion. The MFP is subjected to stress, which is reflected in the form of compressive and tensile strengths. The stress is mainly concentrated the resection line and around the apices of roots of teeth next to the defect. Diversity of designs and techniques were introduced to optimize the stress distribution, such as modification of the clasp design, using materials with different mechanical properties for dentures base and retainer, use of dental (DI) and/or zygomatic implants (ZI), and free flap reconstruction before prosthetic rehabilitation. Conclusion Using ZI in the defective side of the dentulous maxillary defect and defective and nondefective side of the edentulous maxillary defect was found more advantageous, in terms of compression and tensile stress and retention, when compared with DI and free flap reconstruction.

Dynamic navigation and technical improvements in zygomatic surgery

The rehabilitation of the severely atrophied edentulous maxilla poses a great challenge to surgeons and prosthodontics that work on this particular area. The classic approach implies bone augmentation techniques by means of bone grafting, bone distraction techniques, tilted and short implants. All of these require major surgery, sometimes associated with morbidity at donor and receptor sites and functional rehabilitation of the patient must occur in two surgical stages. Since the development of the zygomatic implants by Per-Ingvar Branemark, there’s an alternative to bone grafting techniques, using the body of the zygomatic bone as major point of anchorage to an intraoral osteointegrated implant. This procedure allows the patient to regain orofacial function in only one surgical stage, with high predictability, less morbidity, time spend and costs. In this scientific article the authors present a set of technical improvements in the zygomatic implant (S.I.N. - Implant System, São Paulo, Brazil) in combination with a new dynamic navigation system called StealthStation™ (Medtronic, Dublin, Irland) used for the first time in this type of surgery.

Fully Guided Zygomatic Implant Surgery.

Rehabilitating a severely atrophic maxilla is a complex procedure. In case of severe resorption, zygomatic implants are indicated and loading of the implants at the end of the surgery is desirable. We present a new method by means of guided surgery for the placement of zygomatic implants, using specially designed metal templates that should be supported by bone. The treatment planning for completely guided prosthetic rehabilitation of the maxilla with zygomatic implants was digitally performed. A radiographic template was designed for the prosthetic treatment planning. A surgical template was used to replicate the digitally planned steps in vivo. The procedure ended with the positioning of a custom-made temporary prosthesis. This method can reduce the surgery duration, simplify the procedure, and optimize the outcome. It requires equal cooperation among technicians, prosthodontists, and surgeons. Nineteen out of twenty patients included in the study presented successful implants and prosthesis at the moment of analysis. The present approach addressed the needs for zygomatic-implant surgery. The surgical and prosthetic plan, position, emergence, the shape of the implants, the position of the temporary prosthesis, the inter-arch relationships, and surgical templates were designed in a completely virtual environment and performed by the surgeon on stereolithographic models beforehand. Consequently, the surgical procedure was considerably simplified.

Accuracy of digital planning in zygomatic implants

BackgroundZygomatic implants have been described as a therapeutic alternative for patients with severe maxillary atrophy in order to avoid bone augmentation procedures. Taking that into account, in these treatments, the key factor is the position of the implant, the virtual surgical planning (VSP) is widespread among most clinicians before surgery on the patient. However, there are no studies which evaluate the clinical relevance of these VSP.The aim of this study is to determine whether digital planning on zygomatic implants has any influence on the implant dimensions and position, even when performing conventional surgery afterwards.ResultsFourteen zygomatic implants were placed in four patients. Pre-operative and post-operative helicoidal computed tomography were performed to each patient to allow the comparison between the digital planning and the final position of implants. Tridimensional deviation (TD), mesio-distal deviation (MDD), bucco-palatine deviation (BPD), and apico-coronal deviation (ACD) were evaluated as well as angular deviation (AD). Significative differences in apical TD were observed with a mean of 6.114 ± 4.28 mm (p < 0.05). Regarding implant position, only implants placed in the area of the first right molar reported significant differences (p < 0.05) for ACD. Also, implant length larger than 45 mm showed BPD significative differences (p < 0.05).ConclusionsZygomatic implant surgery is a complex surgical procedure, and although VSP is a useful tool which helps the clinician determine the number and the length of zygomatic implants as well as its proper position, surgical experience is still mandatory.

Evaluation of zygomatic bone region for placement of quad zygomatic implants using CBCT in postmenopausal women

Insufficient height and width of the alveolar ridge at the implant site remains with inadequate bone volume following extraction in older age people especially in postmenopausal women. Postmenopausal women are susceptible to primary osteoporosis where more bone resorption than formation is seen resulting in decreased bone mass. Hence the present study aims to evaluate the zygomatic bone region for placement of quad zygomatic implants using CBCT.: A total of 120 CBCT images of female patients who were between the age group of 45 yrs to 65 yrs were taken. The zygomatic bone was evaluated for pneumatisation zones and thickness of zygomatic bone at three different regions i.e., superior, middle and inferior at nine points on zygoma bone along with bone to implant contact (BIC) region using virtual software. The largest thickness in the superior, middle and inferior regions were at Point A2(8.01+/-2.10 mm), Point B2 (7.01+/-1.62 mm), and Point C1 (6.65+/-1.64 mm), respectively. The virtually placed implants at Point A3 (15.92+/-4.16 mm) and Point B2 (12.02+/-3.62 mm) had the highest BICs. : To obtain the largest BICs, results suggested that the posterosuperior region (Point A3) and the centre of zygoma (Point B1) were the optimal places for the placement of quad zygomatic implants.

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

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

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.

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

Factors influencing implant and prosthesis survival in zygomatic implant-supported fixed rehabilitation: a retrospective study.

The aim of this retrospective study was to evaluate mid-term implant and prosthesis survival in patients with edentulous atrophic maxillae submitted to zygomatic implant-supported fixed rehabilitation and to identify possible related risk factors. Data were collected from records of patients with edentulous atrophic maxillae, in good general health and who were rehabilitated by means of acrylic resin full-arch screw-retained prosthesis supported by at least one zygomatic implant, between the years of 2006-2017. Implant and prosthesis survival rates were calculated. The association between implant and prosthesis loss and quantitative and qualitative variables of interest was verified with t tests and Fisher's exact tests, respectively. For the significant variables in the latter, odds ratio and 95% confidence intervals were additionally calculated. The sample comprised 66 patients in whom 171 zygomatic implants were placed to support maxillary screw-retained full-arch prostheses. Implant and prosthesis survival rates of 94.15% and 92.4%, respectively, were observed in a mean of 3.6years of follow-up (up to 11.7years). Implant loss was 4.33 more likely to occur when adverse events were recorded after the procedure of implant placement (P = 0.026) and 10.31 more likely to occur in implants that had their prosthesis repaired during follow-up visits (P = 0.004). Prosthesis loss was 22.00 times more likely to occur when implants were previously lost (P < 0.001). All prostheses that were considered as failures (i.e. were replaced) had been previously submitted to laboratory repair at some point during follow-up. Zygomatic implant rehabilitation demonstrated to be a reliable method with good mid-term results. The occurrence of post-surgical adverse events and need for laboratory repair of the prosthesis were found to be significant risk factors for implant loss. Previous implant loss was significantly associated with prosthesis loss. These risk factors may be prevented by means of detailed planning of the rehabilitation to be carried out, including post-operative care of the patients, so that treatment success using zygomatic implants can be achieved.

Immediate implant-retained prosthetic obturation after maxillectomy based on zygomatic implant placement by 3D-guided surgery: a cadaver study

BackgroundThe aim of this study was to introduce a complete 3D workflow for immediate implant retained prosthetic rehabilitation following maxillectomy in cancer surgery. The workflow consists of a 3D virtual surgical planning for tumor resection, zygomatic implant placement, and for an implant-retained prosthetic-obturator to fit the planned outcome situation for immediate loading.Materials and methodsIn this study, 3D virtual surgical planning and resection of the maxilla, followed by guided placement of 10 zygomatic implants, using custom cutting and drill/placement-guides, was performed on 5 fresh frozen human cadavers. A preoperatively digitally designed and printed obturator prosthesis was placed and connected to the zygomatic implants. The accuracy of the implant positioning was obtained using 3D deviation analysis by merging the pre- and post-operative CT scan datasets.ResultsThe preoperatively designed and manufactured obturator prostheses matched accurately the per-operative implant positions. All five obturators could be placed and fixated for immediate loading. The mean prosthetic point deviation on the cadavers was 1.03 ± 0.85 mm; the mean entry point deviation was 1.20 ± 0.62 mm; and the 3D angle deviation was 2.97 ± 1.44°.ConclusionsIt is possible to 3D plan and accurately execute the ablative surgery, placement of zygomatic implants, and immediate placement of an implant-retained obturator prosthesis with 3D virtual surgical planning.The next step is to apply the workflow in the operating room in patients planned for maxillectomy.

Zygomatic Implant: State of the Art

&#x0D; Introduction: In the dental implant scenario, the rehabilitation of the maxilla severely reabsorbed with endosseous implants remains a challenge. There are less aggressive alternatives, including short implants, inclined implants, and especially zygomatic (ZI) implants. In cases where the height and width of the residual bone do not allow the placement of conventional dental implants, the ZI can be considered. Objective: Conducted a concise systematic review to analyze the main literary findings on the use of the zygomatic implant as an important alternative for a dental implant, to present the state of the art to the dental community. Methods: The present study followed a concise systematic review model. The search was carried out in the PubMed, Embase, Ovid, Cochrane Library, Web Of Science, and Scopus databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: Zygomatic implants appear to be a consolidated therapeutic option for significantly atrophic maxilla, offering a promising alternative to costly heavy bone graft techniques, fewer complications, less time for rehabilitation, less required prosthodontic work, and significantly higher survival rates. Thus, the zygomatic implant is revolutionizing the implant procedure in the posterior atrophic maxilla, eliminating the complications of bone augmentation and sinus elevation, with delayed healing, showing better clinical results compared to the bone graft, pointing to a possible gold standard for a dental implant.&#x0D;