Implants in the zygomatic bone for maxillary prosthetic rehabilitation: a systematic review

Surgical and prosthetic rehabilitation of siblings with Witkop tooth and nail syndrome using zygomatic implants: a familial case series of 3 patients with up to 15-year follow-up

Witkop tooth and nail syndrome is a rare, autosomal dominant type of ectodermal dysplasia that can have significant effects on dentition, including hypoplastic and malformed dentition and significantly atrophic maxillas. Endosseous implants have become one possible solution to replace missing teeth, although their use in areas where bone is sparse becomes challenging. Due to the severe atrophy of the maxillary alveolus, extensive preprosthetic surgeries including orthognathic surgery, extensive bone grafting, and sinus floor augmentations have been recommended prior to placement of endosseous dental implants. Although this treatment has shown favorable outcomes, it requires multiple surgical procedures, contributing to a prolonged treatment course and increased morbidity. An alternative treatment of atrophic maxillas in patients with ectodermal dysplasia includes the use of zygomatic implants. This familial case series discusses 3 siblings, all previously diagnosed with Witkop Syndrome, who underwent comprehensive preprosthetic surgery and prosthetic rehabilitation using zygomatic implants with a follow-up period up to 15 years.

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.

Treatment alternatives for the rehabilitation of the posterior edentulous maxilla

Rehabilitation of the edentulous maxilla with implant-supported fixed dental prostheses can represent a significant clinical challenge due to limited bone availability and surgical access, among other factors. This review addresses several treatment options to replace missing teeth in posterior maxillary segments, namely the placement of standard implants in conjunction with maxillary sinus floor augmentation, short implants, tilted implants, and distal cantilever extensions. Pertinent technical information and a concise summary of relevant evidence on the reported outcomes of these different therapeutic approaches are presented, along with a set of clinical guidelines to facilitate decision-making processes and optimize the outcomes of therapy.

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

Aim

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

Materials and Methods

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

Results

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

Conclusion

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

Finite Element Analysis (FEA) of a Premaxillary Device: A New Type of Subperiosteal Implant to Treat Severe Atrophy of the Maxilla

Extreme atrophy of the maxilla still poses challenges for clinicians. Some of the techniques used to address this issue can be complex, risky, expensive, and time consuming, often requiring skilled surgeons. While many commonly used techniques have achieved very high success rates, complications may arise in certain cases. In this context, the premaxillary device (PD) technique offers a simpler approach to reconstruct severely atrophic maxillae, aiming to avoid more complicated and risky surgical procedures. Finite element analysis (FEA) enables the evaluation of different aspects of dental implant biomechanics. Our results demonstrated that using a PD allows for an optimal distribution of stresses on the basal bone, avoiding tension peaks that can lead to bone resorption or implant failure. ANSYS® was used to perform localized finite element analysis (FEA), enabling a more precise examination of the peri-crestal area and the PD through an accurate mesh element reconstruction, which facilitated the mathematical solution of FEA. The most favorable biomechanical behavior was observed for materials such as titanium alloys, which helped to reduce stress levels on bone, implants, screws, and abutments. Additionally, stress values remained within the limits of basal bone and titanium alloy strengths. In conclusion, from a biomechanical point of view, PDs appear to be viable alternatives for rehabilitating severe atrophic maxillae.

Zygoma implant under function: biomechanical principles clarified

PURPOSE

The purpose of this document is to clarify the biomechanical principles involved when zygoma implants are placed under functional loads.

METHODS

Two independent reviewers conducted electronic search of the literature from January 2000 to February 2023 describing the biomechanical principles involved using the zygoma implant for maxillary reconstruction. Articles describing the stresses within the zygoma implant, the maxillary bone and the zygoma bone under functional loads were included.

RESULTS

The lack of maxillary boney support at the implant platform resulted in significant higher stress measured within the zygoma implant as well as the zygoma bone.

CONCLUSION

The maxilla is the primary support when zygoma implants are placed under functional loads. Quad-cortical stabilization of the zygoma implants and their cross-arch stabilization are recommended to reduce the degree of stress whenever possible.

Does the Protrusion of Corticobasal Implants in the Maxillary Sinuses Affect Sinus Health? A Retrospective Study

AIM

The aim of this retrospective study is to investigate the effect of corticobasal implant penetration in the nasal and maxillary sinuses on sinus health and implant survival rate in cases of severely atrophid ridges.

MATERIALS AND METHODS

This retrospective study was conducted on thirty patients with 172 implants who underwent corticobasal implant treatment between 2014 and 2018. Implants were divided into two groups according to the penetration depths (Group A, <4 mm; Group B, 4 mm). Inclusion criteria for the study included: (A) patients with severe maxillary ridge resorption with an immediately loaded corticobasal implant-supported prosthesis that showed implant protrusion inside the maxillary sinus on cone-beam computed tomography (CBCT); and (B) patients with a preoperative and postoperative follow-up CBCT scan using the same standard technique and machine. (C) Patients without any history of sinusitis before implant insertion patients who fulfilled the inclusion criteria were recalled for follow-up. The presence of sinus complications was clinically assessed according to the clinical practice guidelines for adult sinusitis of the American Academy of Otolaryngology-Head and Neck Surgery and Radiologically using CBCT. Moreover, patient satisfaction was evaluated using yes-or-no questions. The result was statistically analyzed using Fisher's Exact test.

RESULTS

Despite the differences in implant penetration depths, no clinical signs of sinusitis were evident in any patient. One patient presented with transient epistaxis after the surgery, and 2 patients with nine implants revealed nonsignificant thickening of the sinus membrane radiologically (p = 0.055). All implants showed optimum bone-implant contact with a 100% survival rate. A significant relationship was reported between the thickness of the membrane and the patient's gender, hypertension, and smoking habits. (p = 0.001*, p = 0.002*, and p = 0.034*, respectively).

CONCLUSION

Penetration of corticobasal implants in the maxillary sinus did not compromise the health of the maxillary sinus or implant survival rate.

CLINICAL SIGNIFICANCE

Limited posterior maxillary bony support and maxillary sinus pneumatization present challenges in implant dentistry and increase the possibility of implant protrusion inside the maxillary and nasal cavities. Hence, studying the effect of this protrusion on the maxillary sinuses' health and implant survival is highly significant.

Retrospective analysis of the predictability of using three-dimensional models for preoperative planning of the length of zygomatic implants

PURPOSE

This present study aimed to retrospectively evaluate the predictability of using three-dimensional models (TDMs) to plan the preoperative lengths of zygomatic implants (ZIs).

METHODS

The records of all patients that received such implants between March 2007 and March 2019 were evaluated. The ZI lengths predicted on the TDMs were compared to the lengths of the implants the patients received.

RESULTS

In total, the records of 74 patients were evaluated, of which 37 records met the criteria of inclusion, and were included in the study. Twenty-seven (73%) of the patients were female and 10 (27%) were male, ranging from 34 to 80 years of age, with the average age being 55.7 years. Seventeen (43.2%) of these patients were classified as ASA I and 21 (56.8%) as ASA II. A total of 142 ZIs were planned and installed in the time frame mentioned. Without distinguishing the region of the maxilla, the implants used were, on average, 1.1 mm larger in length than those initially planned.

CONCLUSION

Overall, the data indicates moderate agreement between the planned and surgical lengths of the ZIs and indicates that using TDMs is a predictable and reliable preoperative planning technique of the length of posterior ZIs.

One-stage versus two-stage technique using two splinted extra-short implants: A multicentric split-mouth study with a one-year follow-up

OBJECTIVE

To compare the clinical outcomes of extra-short implants (≤6.5 mm) inserted with one-stage versus two-stage technique in adjacent sites of the upper or lower jaw.

MATERIALS AND METHODS

In this split-mouth multicenter study, implants were randomly divided into two groups according to the healing phase: two-stage and one-stage technique. Primary outcome measures were implant survival, implant success, and prosthodontic complications. Secondary outcome measurements were: implant stability quotient (ISQ) collected at surgery time (T0), and after 3 (T3) and 12 (T12) months, marginal bone level (MBL) evaluated at T0, T3, T6, and T12, marginal bone loss evaluated at T6 and T12, plaque index (PI), probing depth (PD), bleeding on probing (BoP) evaluated at T3, T6, and T12. Significances of differences between groups were tested by linear mixed model with random intercept.

RESULTS

Nineteen patients (8 males and 11 females) were included. A total of 38 implants were inserted. At T12 implant cumulative survival and implant success rate were 100% in both groups. No statistically significant differences were recorded for any of the analyzed parameters between the two groups at any time point. ISQ values were similar at T0 (two-stage: mean 67.53 ± SD 19.47; one-stage: mean 66.53 ± 19.07 p = 0.8738) and increased in both groups at the 12-month follow-up appointment (two-stage: 81.1 ± 7.04; one-stage: 81.39 ± 0.9266). MBL values were similar in the two groups at any time point. At T12 marginal bone loss was 0.46 ± 0.41 (two-stage) and 0.45 ± 0.38 (one-stage) mm (p = 0.9417), while mean PD was 2.7 ± 0.85 (two-stage) and 2.69 ± 0.89 (one-stage) mm.

CONCLUSIONS

Within the limits of the present short-term report, extra-short implants demonstrated optimal clinical outcomes using the one-stage technique, without statistically significant differences compared with the traditional two-stage approach.

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.

Patient Satisfaction regarding Conventional One-Piece Versus Two-Piece Magnet-Retained Obturator for Patients with Complete Edentulism: A Preliminary Crossover Clinical Trial

Purpose:

This study aimed at evaluating patients' satisfaction with conventional one-piece obturators versus two-piece magnet-retained obturators in completely edentulous patient maxillectomy cases.

Materials and Methods:

Ten completely edentulous participants with hemimaxillectomy (8 males and 2 females) were selected in a crossover study. Participants received a conventional obturator one-piece and two-piece obturators connected by magnet attachment in alternate periods (sequences A‐B and B‐A), and outcomes were assessed after 1 week, 3 months, and 6 months Evaluation was made using Obturator Functioning Scale (OFS) and Oral Health Impact Profile for edentulous people (OHIP-EDENT). One way ANOVA test and multivariate analysis of variance with a general linear model with repeated measures was used to test the impact of the group, time, and order on each of the studied scores (α=.05).

Results:

Magnet design showed a statistically significant lower score (P <.050) than the conventional design regarding the overall satisfaction score of OFS along all follow-up periods. Concerning OHIP-EDENT, the magnet design showed a statistically significant lower score (P <.050) than the conventional design regarding total functional limitations, total physical pain, and total social disability along all follow-up periods while for total psychological discomfort, total physical disability, and total handicap, no statistically significant difference was observed between both groups (P >.050).

Conclusion:

Two-pieces magnet-retained obturator could provide better satisfaction and better restoration of orofacial function than the conventional one to manage completely edentulous patients.

Clinical Trial Registration Number:

NCT05066828

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.

Immediate Oral Rehabilitation With Quad Zygomatic Implants: Ultrasonic Technique vs Conventional Drilling

Inserting zygomatic implants is a challenging surgery and requires special care and great precision. Piezoelectric surgery offers several advantages: more precise bone cutting with improved intraoperative visibility and a low temperature increase. The aim of this case-control study was to evaluate whether ultrasonic instruments can be as effective as standard drilling instruments for zygomatic implant surgery in terms of clinical outcomes. Ninety-two patients with atrophic maxilla were included in the study. Implant sites were prepared with the ultrasonic technique (test group = 47 patients) or traditional drilling (control group = 45 patients). In total, 368 zygomatic implants were inserted (202 with the extrasinus technique, 77 with the sinus slot technique, and 89 with the Brånemark technique). Complete arch provisional prostheses were delivered 3 to 5 hours after the surgical operations. The mean follow-up after surgery was 24 months (range = 12-32 months). The primary outcome evaluations were based on implant survival rates and postoperative complications. Operative time and surgeon's stress were evaluated as secondary outcomes. Implant survival rate was 100% in the test and 98.89% in the control group. Postoperative complications were seen in 9 patients (4 in the test and 5 in the control group); the difference was not statistically significant. Operative time was longer in the test group; however, surgeons were more comfortable using ultrasonic instruments. Within the limitations of this preliminary study, the ultrasonic technique was a feasible alternative to traditional drilling for zygomatic implant surgery.

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.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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 3.6 years of follow-up (up to 11.7 years). 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.

CONCLUSIONS

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.

A zygomatic bone study using virtual dental implant planning software

This study evaluated the anatomical factors that influence the virtual planning of zygomatic implants by using cone beam computerized tomography (CBCT) scans. CBCT scans of 268 maxilla edentulous patients were transferred to a specialized implant planning software (Galaxis, Sirona) for the following measurements: maxillo-sinus concavity size (small, medium, and large), Zygoma width, implant insertion angle, implant length, and implant apical anchorage. Concavity sizes found were as follows: 34.95% small, 52.30% medium, and 7.35% large. The mean insertion angle was 43.2 degrees and the average implant apical anchorage was 9.1mm. The most frequent implant length was 40mm. Significant differences were found when the different types of concavities in relation to the installation angle, the distance of the apical portion of the implant in contact with the zygomatic bone and the lateral-lateral thickness of the zygomatic bone were compared (p<0.001). Medium-sized maxillary sinus concavity presented greater apical anchorage of the implant (9.7mm) and was the most frequent type (52.30%). The zygomatic bone is a viable site for zygomatic fixtures and the use of specialized implant planning software is an important tool to achieve predictable outcomes for zygomatic implants and allows good visualization of the implant-anatomical structures relation.

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

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

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

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

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

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

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.

Three-Dimensional Technology Applications in Maxillofacial Reconstructive Surgery: Current Surgical Implications

Defects in the oral and maxillofacial (OMF) complex may lead to functional and esthetic impairment, aspiration, speech difficulty, and reduced quality of life. Reconstruction of such defects is considered one of the most challenging procedures in head and neck surgery. Transfer of different auto-grafts is still considered as the “gold standard” of regenerative and reconstructive procedures for OMF defects. However, harvesting of these grafts can lead to many complications including donor-site morbidity, extending of surgical time, incomplete healing of the donor site and others. Three-dimensional (3D) printing technology is an innovative technique that allows the fabrication of personalized implants and scaffolds that fit the precise anatomy of an individual’s defect and, therefore, has attracted significant attention during the last few decades, especially among head and neck surgeons. Here we discuss the most relevant applications of the 3D printing technology in the oral and maxillofacial surgery field. We further show different clinical examples of patients who were treated at our institute using the 3D technology and discuss the indications, different technologies, complications, and their clinical outcomes. We demonstrate that 3D technology may provide a powerful tool used for reconstruction of various OMF defects, enabling optimal clinical results in the suitable cases.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Management of Maxillary Cluster Implant Failures with Extra-Maxillary Implants: A Clinical Report

Late cluster implant failures can be one of the most devasting outcomes of implant therapy for patients. It can have anatomic, functional, psychological and financial consequences for patients, and sometimes the loss of residual bone can preclude subsequent implant placement. Fortunately, management of cluster implant failures in the maxilla can be mitigated by using implant anchorage from remote sites like zygomatic and pterygoid regions. Few reports exist in the literature that have described the management of cluster implant failure using extra-maxillary implants such as zygomatic and pterygoid implants. This case report describes the management of a female patient with bruxism who experienced late cluster implant failure in the maxilla after 9 years of function with an overdenture. Due to the loss of residual bone, subsequent implant therapy involved the use of bilateral zygomatic, pterygoid and anterior maxillary implants, which were immediately loaded and thereafter used to support a complete arch fixed implant-supported zirconia prosthesis.

A Novel Approach for Rehabilitation of a Subtotal Maxillectomy Patient with Immediately Loaded Basal Implant-Supported Prosthesis: 4 Years Follow-Up

The prosthetic rehabilitation of maxillary defect can be achieved successfully by using an implant-supported prosthesis. The use of remote bony areas such as the zygomatic bone in cases of large defects provides an innovative substitute for free vascularized osteocutaneous flaps and the solution to flap failures. This report describes the rehabilitation of a 22-year-old female with a subtotal maxillectomy using an immediately loaded basal implant-supported prosthesis. Four basal cortical screw implants (BCS®) are inserted; 1 on the contralateral nasal floor, 2 implants in the pterygoid plates, and the last in the zygomatic bone using cone beam computed tomography scans. The prosthesis was constructed and cemented in 3 days. The surgical and prosthetic procedures were performed without any obstacles. After 4 years in function, the patient was highly satisfied with the treatment as it improved her mastication, speech, aesthetic and returned her self-esteem. To our knowledge, this is the first clinical report detailing the use of basal implant-retained obturator in a subtotal maxillectomy patient.

Masticatory performance and oral health-related quality of life in edentulous maxillectomy patients: A cross-sectional study to compare implant-supported obturators and conventional obturators

OBJECTIVE

The aim of this cross-sectional study was to compare the masticatory performance and oral health-related quality of life (OHRQoL) of edentulous maxillectomy patients with and without implant-supported obturator prostheses.

MATERIAL AND METHODS

Nineteen edentulous maxillectomy patients with completed prosthetic obturator treatment in the upper jaw participated in this study. In nine patients, the obturator prosthesis was supported by implants in the remaining bone of the midface and/or skull base to improve retention. Masticatory performance was measured objectively by the mixing ability test (MAT) and subjectively by three OHRQoL questionnaires: (a) the Oral Health Impact Profile for EDENTulous people (OHIP-EDENT), (b) the Obturator Function Scale (OFS), and (c) the Dutch Liverpool Oral Rehabilitation Questionnaire version 3 (LORQv3-NL). The independent t test and the Mann-Whitney U test were used to test for differences in outcomes of patients with and without implant-retention of their obturator prostheses.

RESULTS

Patients with implant-supported obturator prostheses had significantly better masticatory and oral function, reported fewer chewing difficulties, and had less discomfort during food intake than did patients with a conventional obturator.

CONCLUSION

Supporting prosthetic obturators after maxillectomy with implants improve oral functioning, chewing, and eating comfort. This treatment modality is a viable technique to improve the functionality of prosthetic rehabilitation in patients who have undergone maxillectomy.

TEN-YEAR follow-up of treatment with zygomatic implants and replacement of hybrid dental prosthesis by ceramic teeth: A case report

The aim of this case report was to show the 10-year follow-up of a zygomatic implant supported rehabilitation treatment to replace the hybrid dental prosthesis with resin teeth - one by one - with ceramic teeth. The complications that occurred were described right from the time when the first implant supported prosthesis with immediate loading was placed, through the fabrication of a personalized dental prosthesis with twelve ceramic crowns, with a view to achieving esthetic excellence and restoring the patient's self-esteem. It was concluded that all patients with zygomatic implants must participate in a preventive maintenance program to assure the predictability of this type of treatment.

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Surgery may occur in the private clinic with local anesthesia and oral sedation.

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Treatments have high success rates, improvement in quality of life.

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All patients must participate in a preventive maintenance program.

Maxillofacial Rehabilitation With Zygomatic Implants in an Oncologic Patient: A Case Report

Tumor ablation results in significant sequelae in the appearance, function, and esthetics of a patient with cancer, especially resection for head and neck cancer. Reconstruction with local and microvascular flaps is a workable option; however, the esthetic results will occasionally be unfulfilling and inadequate for the rehabilitation of lost structures. Prosthetic rehabilitation with conventional and zygomatic implants can provide favorable and predictable long-term results. We report the clinical case of a 53-year-old female patient with adenoid cystic carcinoma (ACC). The treatment protocol included radical surgery, radiotherapy, and maxillofacial rehabilitation with conventional and zygomatic implants. Management of an ACC case requires a timely, radical, and multidisciplinary approach. In our patient, rehabilitation of masticatory function was accomplished in the immediate postoperative period and before radiotherapy. The rehabilitation of masticatory function improved the patient's systemic and nutritional status and her speech, with coverage of the esthetic defect. These outcomes reduced the psychological and emotional effects of tumor ablation.

Three-dimensional descriptive study of the pterygomaxillary region related to pterygoid implants: A retrospective study

The objective of this study was to analyze three-dimensionally the morphological characteristics of the pterygomaxillary region related to pterygoid implants. Volume, height, width and bone density were studied in relation to age, sex and dental status. This retrospective observational study analyzed the CBCT of 52 hemi-maxillas three-dimensionally (females n = 28, males n = 24; dentate = 31, edentulous = 21). Patients were exposed between September 2009 and October 2014, and data collection was performed between November 2015 and May 2016. Bone density, volume, height and width were analyzed in various locations of the maxilla and pterygoid process, and the variables age, gender and dental status patients were compared. The results show that the mean width of the pterygomaxillary joint was 7.5 mm (SD 1.00 mm), mean height was 12.51 mm (SD 1,82 mm) and mean volume was 321.7 mm³ (SD 142.02 mm³). Statistically significant differences between dentate and edentulous patients were found, showing a higher osseous density in dentate patients in the pterygoid process (758.2, SD 106.8, 95% CI 729.2 to 787.3 GSD - Gray Scale Density - compared to 689.9, SD 107.3, 95% CI 660.8 to 719.1 GSD; P = 0.022). In the maxilla, density was statistically significant lower in female subjects (571.0, SD 74.1, 95% CI 594.9 to 645.4 GSD) than in male subjects (620.2, SD 93.8, 95% CI 594.4 to 645.4 GSD, P = 0.047). In conclusion, due to the significant variation in the morphological characteristics of the pterygomaxillary region among subjects, personalized pre-surgical radiological assessment should always be performed. Gender, age and dental status are critical factors as they significantly affect bone density in this region.

Horizontal augmentation of the maxillary alveolar ridge to change the prosthetic profile: Clinical and radiological results of a retrospective study

BACKGROUND

In this retrospective study, we aimed to analyze the clinical and radiological results of compensating the long-term deficiencies in hard and soft tissues of edentulous patients by placing dental implants and performing a horizontal ridge augmentation.

MATERIAL AND METHODS

We treated patients with edentulous maxillaries (Cawood-Howell type III or IV) by combining 4 implants, or 6 implants, or using zygomatic and conventional anterior implants as appropriate. Simultaneously, horizontal ridge augmentation was performed by combining autologous bone with Bio-Oss and membranes.

RESULTS

A total of 14 zygomatic and 80 standard implants were used for the rehabilitations in 16 edentulous patients. The success rates were 93.75% and 85.71% for the standard and zygomatic implants, respectively. Also, respective gains of 5.79mm and 3.25mm were obtained at the levels of the midsagittal line and canines, with respective resorption rates of 10% and 8.6% after 20months.

CONCLUSION

The millimeters gained by performing a horizontal augmentation optimizes the relation between the implant position and the prosthetic profile. This allows the different prostheses to be selected and for rehabilitation to be optimized. In this way, mucosal coverage can be avoided and fixed prosthetic design can be enhanced.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Can Genetic Factors Compromise the Success of Dental Implants? A Systematic Review and Meta-Analysis

Dental implants provide a predictable treatment option for partial and complete edentulism via the placement of a fixed permanent artificial root to support prosthetic dental crowns. Despite the high survival rates, long-term dental implant failures are still reported, leading to implant removals and additional financial and health burdens. While extrinsic factors that improve the success rate of implants have been well explored, the impact of genetic factors on this matter is poorly understood. A systematic review and meta-analysis study was conducted to determine whether genetic factors contribute to an increased risk of dental implant failures. A comprehensive search for peer-reviewed articles on dental implants and genetic factors was performed using various literature database libraries. The study design was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, and the obtained records were registered in the International Prospective Register of Systematic Reviews (PROSPERO) database. According to the exclusion/inclusion criteria, 13 studies were eligible for this study out of 809 articles. The meta-analysis of the combined association studies of DNA variations and dental implants did not indicate an increased risk for implant failure due to DNA variations in IL-1B, IL-10 and TNF-α. This study emphasizes the need for larger randomized controlled clinical trials to inform clinicians and patients about the role of genetic factors on dental implant survival and the success rate in healthy and compromised patients.

Stresses generated by two zygomatic implant placement techniques associated with conventional inclined anterior implants

Purpose

To make a comparative evaluation, by means of the finite element method, of the stress generated on supporting tissues and prosthetic system components, using zygomatic implants with the exteriorized and extramaxillary techniques, and different placement positions, associated either with inclined anterior implants, or those without inclination.

Materials and methods

Eight (8) tridimensional models were created to represent the clinical situations being researched, using the dataset of scanned images of an edentulous model. The implants and prosthetic components were photographed on millimeter paper and inserted into Rhinoceros 3D modeling computer software. From the measurements made on the image, the virtual models were made. The application force was distributed on the occlusal surface of the working side of the left maxillary first molar, first and second premolars, and incisal regions of the central incisor, simulating the occlusal load during mastication, in a total of 150 N.

Results

The extramaxillary technique presented considerable variation in increased tension on the prosthesis screws and bone tissue. In the exteriorized technique, the highest tension values occurred in the region of the ridge, and the lowest, on the zygomatic process; the absence of cantilever reduced the stress on bone tissue in almost all regions.

Conclusion

The exteriorized technique was shown to be more favorable to the distribution of stresses on the micro-unit screws and bone tissue, with the model with zygomatic implant placed in the region of the first molar and inclined anterior implant presenting the best results.

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The extramaxillary technique showed considerable variation in stress increase.

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In the exteriorized technique, the highest stress occurred in the alveolar ridge region.

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The alveolar bone support for zygomatic implants reduced the internal stress generated by the vertical force.

Management of Zygomatic Fixture Complication Case Using Extra-Short Implants

The oral rehabilitation of a patient with atrophic maxilla is one of the main challenges in implant-supported rehabilitations. The implant placement in the posterior region of the maxilla is limited by a deficiency of bone quantity and quality, besides the anatomic restriction of the maxillary sinus. The use of zygoma fixtures, anchoraged in the zygomatic bone, is a useful technique to enable the full arch rehabilitation. However, complications related to this procedure bring a lot of difficulty in solving. This study presents the use of extra-short implants as a strategy to treat a patient in whom the zygoma fixture and the fixed prosthesis failed, associated with sinusitis and alveolar bone loss.

Measurement of the zygomatic region for the optimal placement of quad zygomatic implants

BACKGROUND

The zygomatic implant is suggested to be placed in zygomatic areas with the largest thickness, but regions to obtain the largest bone-to-implant contact (BIC) were unknown.

PURPOSE

To identify the zygomatic regions for placing quad zygomatic implants that obtain the largest BIC.

MATERIALS AND METHODS

The zygomatic thicknesses of 300 zygomata were measured at total 12 points on the superior, middle, and inferior areas on the 3-dimensional reconstruction images. In 50 edentulous maxillae, the zygomatic BICs of virtually placed implants were measured and the incidence of the intrusion into the infratemporal fossa calculated at each point.

RESULTS

The largest thickness in the superior, middle, and inferior regions were at Point A₁ (8.01 ± 2.10 mm), Point B₁ (7.02 ± 1.73 mm), and Point C₀ (6.65 ± 1.66 mm), respectively. The virtually placed implants at Point A₃ (16.70 ± 4.18 mm) and Point B₁ (12.07 ± 3.84 mm) had the highest BICs while retaining the minimum incidence of the intrusion complications.

CONCLUSION

To obtain the largest BICs and avoid the intrusion complications, results suggested that the postero-superior region (Point A₃ ) and the center of zygoma (Point B₁ ) were the optimal places for the placement of quad zygomatic implants.

Immediate full-arch rehabilitation of the severely atrophic maxilla supported by zygomatic implants: a prospective clinical study with minimum follow-up of 6 years

The aim of this study was to evaluate the outcomes of immediate full-arch prostheses supported by zygomatic implants alone or in combination with standard fixtures after a minimum of 6 years of loading. From October 2008 to April 2010, 15 patients with severely atrophic maxillae were treated using four zygomatic implants or two zygomatic implants in conjunction with two conventional fixtures. All subjects received a fixed screw-retained prosthesis within 3hours of surgery, while the final restoration was delivered after 6 months. Follow-up examinations were scheduled to evaluate zygomatic implant survival, conventional dental implant success, prosthetic success, plaque and bleeding scores, marginal bone loss for conventional dental implants, and patient satisfaction. Forty-two zygomatic fixtures and 18 standard implants were placed. Patients were followed up for a minimum of 79 months (range 79-97 months, average 90.61 months). No implant was lost, leading to implant and prosthetic survival rates of 100%. Bone loss for conventional implants averaged 1.39±0.10mm after 6 years of function, leading to a 100% implant success rate. High levels of patient satisfaction were recorded. These medium-term results indicate that immediate full-arch rehabilitation supported by zygomatic implants could be considered a viable treatment modality for the severely atrophic maxilla.

Dental implants in patients with osteoporosis: a systematic review with meta-analysis

There is currently no consensus regarding the survival rate of osseointegrated implants in patients with osteoporosis. A systematic review with meta-analysis was performed to evaluate the survival rate of implants in such patients. The PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO databases were used to identify articles published up to September 2016. The systematic review was performed in accordance with PRISMA/PICO requirements and the risk of bias was assessed (Australian National Health and Medical Research Council scale). The relative risk (RR) of implant failure and mean marginal bone loss were analyzed within a 95% confidence interval (CI). Fifteen studies involving 8859 patients and 29,798 implants were included. The main outcome of the meta-analysis indicated that there was no difference in implant survival rate between patients with and without osteoporosis, either at the implant level (RR 1.39, 95% CI 0.93-2.08; P=0.11) or at the patient level (RR 0.98, 95% CI 0.50-1.89; P=0.94). However, the meta-analysis for the secondary outcome revealed a significant difference in marginal bone loss around implants between patients with and without osteoporosis (0.18mm, 95% CI 0.05-0.30, P=0.005). Data heterogeneity was low. An increase in peri-implant bone loss was observed in the osteoporosis group. Randomized and controlled clinical studies should be conducted to analyze possible biases.

Complications of Zygomatic Implants: Our Clinical Experience with 4 Cases

Zygomatic implants have been used for rehabilitation of the edentulous atrophic maxilla as an alternative to bone grafting for almost two decades resulting in satisfactory clinical outcomes. However, the patients with edentulous atrophic maxilla treated using this technique may present serious complications that could put the prosthetic restoration at risk. Four cases are reported in this paper, one case with a cutaneous fistula in the left zygomatic-orbital area caused by aseptic necrosis at the apical part of the implant, which was treated with the surgical removal of this part, a second case with loss of the right zygomatic implant due to failure of osseointegration and two cases of periimplantitis that resulted in partial and complete removal of the implant, respectively. All patients who had complications were treated without compromising the restoration which remained functional after appropriately modified treatment.