Asymptomatic chronic rhinosinusitis and osteitis in patients treated with multiple zygomatic implants: a long-term radiographic follow-up

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

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

Preliminary study on AI-assisted diagnosis of bone remodeling in chronic maxillary sinusitis

OBJECTIVE

To construct the deep learning convolution neural network (CNN) model and machine learning support vector machine (SVM) model of bone remodeling of chronic maxillary sinusitis (CMS) based on CT image data to improve the accuracy of image diagnosis.

METHODS

Maxillary sinus CT data of 1000 samples in 500 patients from January 2018 to December 2021 in our hospital was collected. The first part is the establishment and testing of chronic maxillary sinusitis detection model by 461 images. The second part is the establishment and testing of the detection model of chronic maxillary sinusitis with bone remodeling by 802 images. The sensitivity, specificity and accuracy and area under the curve (AUC) value of the test set were recorded, respectively.

RESULTS

Preliminary application results of CT based AI in the diagnosis of chronic maxillary sinusitis and bone remodeling. The sensitivity, specificity and accuracy of the test set of 93 samples of CMS, were 0.9796, 0.8636 and 0.9247, respectively. Simultaneously, the value of AUC was 0.94. And the sensitivity, specificity and accuracy of the test set of 161 samples of CMS with bone remodeling were 0.7353, 0.9685 and 0.9193, respectively. Simultaneously, the value of AUC was 0.89.

CONCLUSION

It is feasible to use artificial intelligence research methods such as deep learning and machine learning to automatically identify CMS and bone remodeling in MSCT images of paranasal sinuses, which is helpful to standardize imaging diagnosis and meet the needs of clinical application.

Rapid Smile Restoration: Basal Implants for the Edentulous Mandible With Immediate Loading

In the significant atrophic jaws, it is difficult to place dental implants since there is a qualitative and quantitative shortage of future implant beds. Basal implants, also known as cortical or bicortical implants, offer a viable alternative for dental rehabilitation in patients with significant alveolar bone loss. These implants are anchored in the dense basal bone, providing immediate stability and allowing for immediate loading, thereby reducing overall treatment time and eliminating the need for extensive bone grafting procedures. This case report demonstrates the efficacy of basal implants in providing immediate functional and aesthetic restoration for patients with significant alveolar bone loss, by describing a 49-year-old patient who presented with severe alveolar ridge resorption, making traditional implant placement unfeasible. Basal implants were successfully placed, and an immediate prosthesis was delivered, resulting in excellent functional and aesthetic outcomes.

Revolutionizing Maxillary Rehabilitation: Zygomatic Implants Addressing Severe Alveolar Atrophy

This case report describes the care given to a 58-year-old male patient with severe upper jaw atrophy. The treatment strategy involved utilizing zygomatic implants in conjunction with endosteal implants to rehabilitate both the maxilla and mandible. Temporary prostheses were used during the healing phase, followed by the fabrication and placement of final prostheses. The utilization of zygomatic implants offers advantages such as immediate stabilization and function without the need for extensive bone grafting. This approach not only reduces treatment time and costs but also enhances patient outcomes. Furthermore, guided surgical techniques are increasingly employed to ensure precise implant placement, optimizing prosthetic support.

Longitudinal reactions of maxillary sinus in patients treated with multiple zygomatic implants: A modified radiographic evaluation with clinical follow-up

OBJECTIVES

To investigate the effects of zygomatic implant placement on the maxillary sinus using radiographic and clinical indicators.

METHODS

Patients with an atrophic maxilla who underwent zygomatic implant placement were included. The thickness and morphology of the Schneiderian membrane (SM), infundibular obstruction, and posterior bone wall of the maxillary sinus were analyzed. The generalized estimating equation and chi-square tests were performed to compare the measurements.

RESULTS

Fifty patients with 100 maxillary sinuses were included. In total, 148 zygomatic implants and 105 regular implants were placed in the maxilla. Overall, the mean pre- and postoperative SM thickness was 2.79 ± 3.26 mm and 3.97 ± 5.45 mm, respectively (p = 0.063). In sinuses with two zygomatic implants, the SM thickness increased significantly from 2.12 ± 2.14 mm preoperatively to 4.07 ± 6.14 mm postoperatively (p = 0.026). The number of sinuses with type IV morphology (fully radiopaque) increased from zero preoperatively to six (13%) postoperatively. Sinuses with a single zygomatic implant showed no difference in the pre- and postoperative SM thickness. Postoperatively, six sinuses had infundibulum obstructions. Postoperative osteitis of the bilateral sinuses was found in two patients.

CONCLUSIONS

We have proposed a new imaging evaluation method and system for evaluating the maxillary sinus response. Preoperative infundibulum obstruction combined with mucosal thickening and double zygomatic implant placement are more likely to induce postoperative maxillary sinus mucositis and osteitis.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Indications for zygomatic implants: a systematic review

PURPOSE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Computed Tomography Evaluation of Unilateral Chronic Maxillary Sinusitis With Osteitis

BACKGROUND

Computed tomography (CT) is the preferred noninvasive method for the evaluation of osteitis in chronic sinusitis. Some scholars believe that the bone changes associated with chronic sinusitis always show high attenuation (high density) and are positively correlated with the severity of the disease. However, sinus bone remodeling is a complex process that may cause high or low attenuation. There have been few reports on the spread of osteitis. Therefore, additional research on sinus CT is necessary.

OBJECTIVE

To observe bony changes in chronic maxillary sinusitis (CMS) by CT and reveal the mechanism.

METHODS

A retrospective study was conducted in 45 patients with unilateral CMS with bony changes in the sinus walls. The patients' clinical data and CT results were analyzed and compared between the affected and normal sides. We propose the location, involvement, attenuation, and thickness method to evaluate CMS with osteitis.

RESULTS

Of the 45 patients, 40 (88.9%), 2, 12, and 7 had posterior external, medial, anterior, and superior lesions, respectively. The nasal region, sphenoid bone, palatine bone, and zygomatic arch were involved in 3, 12, 8, and 18 (40%) patients, respectively. Computed tomography indicated high attenuation in 30 (75.0%) and low attenuation in 10 (25.0%) patients; 6 (15.0%) showed new bone marrow cavities. The bone thickness was significantly different between the affected and normal sides in 40 patients (P < .001), including members of both the high- and low-attenuation groups (high-attenuation group: P < .001; low-attenuation group: P < .01). However, there was no significant difference in the thickness of the affected side between the high- and low-attenuation groups (P > .05).

CONCLUSIONS

Chronic rhinosinusitis with bony changes may occur in the maxillary sinus walls and spread to adjacent bones. Both increased and decreased attenuation may occur in these circumstances. Analyzing the CT features of bone changes in unilateral CMS can improve the accuracy of disease diagnosis.

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.

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.

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.

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

OBJECTIVES

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Survival and Complications of Zygomatic Implants: An Updated Systematic Review

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Are Zygomatic Implants Associated With Maxillary Sinusitis?

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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