Maxillary Sinus Augmentation Research Articles

Maxillary Sinus Osteoma as a Support for Dental Implant Associated to Sinus Augmentation Procedure: A Case Report and Literature Review

Background: Maxillary sinus augmentation is a method extensively used to restore sufficient bone volume in the posterior maxilla to allow for the placement of fixtures. The purpose of the present case report was to describe a rare case of sinus osteoma used for implant support and to review the relevant literature. Materials and Methods: A 58-year-old man with a radiopaque intrasinusal lesion was referred for rehabilitation of the maxilla. The lesion was probably an osteoma and involved the nasal wall of the maxillary sinus. After discussing the options with the patient, he agreed to maintain the lesion and a sinus augmentation with a bone graft. A part of the osteoma was partially removed for histological analysis while avoiding perforation or tearing of the schneiderian membrane. After six months, 6 implants (Bone System Implant, Milano, Italy) were placed in the maxilla, two of which were inserted in the osteoma. Results: The two implants placed in the osteoma were perfectly osseointegrated. The graft material appeared well-integrated with no local signs of inflammation. No postoperative events or symptoms were reported after the surgery stages and at a 6-month follow-up. Regarding the two implants placed in the osteoma: article selection identified 9 case reports, 2 case series, and 1 retrospective study for a total of 58 subjects, 35 males and 25 females. The patients’ ages were heterogeneous and ranged between 12 and 79 years old. Conclusions: In the present case, we decided to leave the osteoma because it was asymptomatic and used as dental implant support. The effectiveness of the present investigation can provide useful guidance for surgeons and dentists in the management of similar clinical situations.

Comparison of biological and mechanical properties of different paranasal sinus mucosa in goat

ObjectiveThe present study was designed to explore endurable pressure intensity of different paranasal sinus mucosa in goats.MethodMucosa commonly involved in maxillary sinus augmentation, including mucosa from maxillary sinus crest, maxillary sinus floor, and frontal sinus, were harvested in a computed tomography-guided manner. The obtained mucosa was then sectioned into square and irregular ones for maximum endurable pressure intensity determination and morphological observation, respectively.ResultsThickness of paranasal sinus mucosa, as determined under morphological staining by an optical microscope with a graduated eyepiece, were calculated. And the results showed that the average thickness of maxillary sinus crest mucosa, floor mucosa, and frontal sinus mucosa in goats were 410.03 ± 65.97 μm, 461.33 ± 91.37 μm and 216.90 ± 46.47 μm, respectively. Significant differences between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus were observed (P < 0.05). Maximum endurable pressure intensity was determined by utilizing a self-made clamp device and the results revealed maximum endurable pressure intensity of maxillary sinus crest mucosa, floor mucosa and frontal sinus mucosa in goats were 260.08 ± 80.12Kpa, 306.90 ± 94.37Kpa and 121.72 ± 31.72Kpa, respectively. Also, a statistically significant difference was observed when comparing the endurable pressure intensity between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus (P < 0.05). Further correlation analysis also revealed a positive correlation between the thickness of mucosa of the maxillary sinus and frontal sinus and maximum endurable pressure intensity (P < 0.05).ConclusionMucosal thickness and maximum endurable pressure intensity of maxillary sinus crest and floor were larger than that of frontal sinus mucosa and a positive correlation between the thickness of mucosa and endurable pressure intensity was observed. Our results thus might provide an experimental basis and guidance for mucosa-related problems involved maxillary sinus augmentation.

Comparative analysis of lateral maxillary sinus augmentation with a xenogeneic bone substitute material in combination with piezosurgical preparation and bony wall repositioning or rotary instrumentation and membrane coverage: a prospective randomized clinical and histological study

ObjectivesThe present randomized controlled clinical study aimed to investigate if, in lateral maxillary sinus augmentation, the repositioned bony wall or the application of a collagen membrane results in more preferable new hard tissue formation.Materials and methodsForty patients were divided into two study groups. Both groups received a xenogeneic bone substitute material (BSM) during lateral sinus augmentation. In the bony wall group (BW), following piezosurgery, the retrieved bony wall was repositioned. In the collagen membrane group (CM), following rotary instrument preparation, collagen membrane coverage was applied. After 6 months, biopsies were taken to histologically analyze the percentage of BSM, connective tissue (CT), and newly formed bone (NFB) following both approaches.ResultsForty implants were placed and 29 harvested biopsies could be evaluated. Duration of surgery, membrane perforations, and VAS were detected. Histomorphometrical analysis revealed comparable amounts of all analyzed parameters in both groups in descending order: CT (BW: 39.2 ± 9%, CM: 37,9 ± 8.5%) > BSM (BW: 32.9 ± 6.3%, CM: 31.8 ± 8.8%) > NB (BW: 27.8 ± 11.2%, CM: 30.3 ± 4.5%).ConclusionsThe results of the present study show that the closure of the access window by means of the retrieved bony wall or a native collagen membrane led to comparable bone augmentation results.Clinical trialclinicaltrials.gov NCT04811768.Clinical relevanceLateral maxillary sinus augmentation with the application of a xenogeneic BSM in combination with a native collagen membrane for bony window coverage represents a reliable method for surgical reconstruction of the posterior maxilla. Piezosurgery with bony window repositioning delivers comparable outcomes without membrane coverage.

Radiographic Analysis of Graft Dimensional Changes after Lateral Maxillary Sinus Augmentation with Heterologous Materials and Simultaneous Implant Placement: A Retrospective Study in 18 Patients.

Background: This investigation aimed to radiographically assess the variations of graft dimension following maxillary sinus augmentation by the lateral approach. Methods: Eighteen patients (seven males), with a mean age at surgery of 66.5 ± 9.8 (range 52–82) years, were unilaterally treated. Thirty-five dental implants were positioned in the posterior maxilla simultaneously to grafting with heterologous biomaterials. Intraoral radiographs taken at the time of surgery, after six months, and at the longest follow-up (up to nine years after implant placement) were analyzed. The following distances were measured: mesio-distal width of the graft, vertical distance from implant apex to most coronal level of the graft, distance from the mesial aspect of the (mesial) implant to the mesial graft extension; distance from the distal aspect of the (distal) implant to the distal graft extension, and graft height along the implant axis. The dimensional changes with respect to baseline, after six months and at the longest follow-up were calculated. Results: The patient-based mean follow-up was 38.3 ± 30.1 months (range 12–108 months). The mean residual bone height at the mesial and distal aspect of the implants was 3.19 ± 2.05 mm and 2.65 ± 1.60 mm, respectively (p = 0.38). The mean graft width at baseline was 27.95 ± 5.23 mm, and the mean graft width reduction was 10.2 ± 12.7% (2.98 ± 3.62 mm) and 11.3 ± 14.4% (3.36 ± 4.08 mm) at six months and at the latest follow-up. The change was significant at six months (p = 0.005), but did not show significant further variation (p = 0.11). On the mesial and distal aspect, the mean graft extension decreased by 1.56 ± 2.67 mm and 0.84 ± 2.71 mm at the latest follow-up. No significant difference between mesial and distal changes was found (p = 0.24), suggesting that the biomaterial is resorbed homogeneously on both sides. The mean graft height was 11.92 ± 2.53 mm at baseline and decreased by 9.3 ± 9.05% (1.11 ± 1.09 mm) at six months (p < 0.001). Non-significant further changes were found at the latest follow-up (p = 0.10). Conclusions: after early remodeling, heterologous bone substitutes showed a good dimensional stability in the mid-term for maxillary sinus augmentation.

Radiographic Analysis of Graft Dimensional Changes in Transcrestal Maxillary Sinus Augmentation: A Retrospective Study.

Background. The maxillary sinus lift is a popular and predictable technique associated with implant-supported rehabilitation of the severely atrophic maxilla. The aim of the present retrospective study was to investigate the effectiveness of transcrestal maxillary sinus augmentation and the graft resorption pattern using different heterologous bone substitutes. Methods. A total of 75 sinus-grafting procedures were performed and 89 implants were placed in 66 patients, 24 males and 42 females, with mean age 67.9 ± 10.64 years (range 43–84 years). Nineteen subjects were smokers. The mean follow-up period was 93.33 ± 54.71 months (range 14–240 months). Clinical and radiographical evaluations were performed. Graft height and width were measured at baseline and at the latest follow-up. Results. Mesiodistal and vertical resorption averaged 9.3 ± 20.7% (standard deviation), and 5.04 ± 9.9% of the postoperative size, respectively, considering the graft as the unit. Linear regression analysis showed that graft resorption in both the vertical and the mesiodistal dimension is independent of the follow-up time. Conversely, there was a trend for greater resorption when increasing the postoperative graft size, in both vertical (p = 0.001) and horizontal (p = 0.007) dimensions. When grouping the dimensional changes by graft particle size (only small (<300 μm) particles, combination of small and medium (>500 μm)/large (>1000 μm) particles, and only medium/large particles), there was a trend for greater resorption associated with smaller particles, but it was not significant; neither in the mesiodistal nor in the vertical dimension (p = 0.17 and p = 0.25, respectively). No implant was lost during the observation period. In conclusion, the transcrestal technique for maxillary sinus augmentation documented a high level of predictability. The low clinical morbidity and the contextual dental implant positioning is clinically useful in relation to a significant reduction of the time required for implant restoration, a consistent decrease of the number of surgical phases, and a cost-effectiveness approach for the rehabilitation. The graft resorption pattern in all cases was compatible with persistent implant protection and support.

Effects of missing teeth and nasal septal deviation on maxillary sinus volume: a pilot study

PurposeTooth extraction and the projection of the tooth roots into the maxillary sinus are reported to greatly reduce the bone height from the alveolar ridge to the maxillary sinus floor, while missing teeth are reported to lead to the expansion of the maxillary sinus, all of which are important considerations during dental implant treatment for the maxillary molar region. Therefore, assessing the anatomical characteristics of the maxillary sinus acting as complicating factors is crucial before sinus augmentation. We conducted a three-dimensional examination of the effects of missing teeth and nasal septal deviation (NSD) on maxillary sinus volume (MSV).MethodsWe selected participants with two or more missing teeth from patients who underwent maxillary sinus augmentation for a unilateral free-end saddle between April 2019 and December 2020. We calculated the MSV and NSD using cone-beam computed tomography (CBCT). We compared the relationships of the presence/absence of teeth and NSD with MSV bilaterally in each patient using the Wilcoxon t-test. p-values < 0.05 denoted statistical significance.ResultsThis study included 30 patients (30 sinuses; 12 men, 18 women). The average patient age was 58.2 ± 10.2 years (men, 60.4 ± 3.7 years; women, 59.2 ± 4.5 years; range, 40–77 years). The mean number of missing teeth was 2.98 ± 1.01: 13 patients had two missing teeth and 17 had three or more missing teeth. Nine patients (30%) had NSD. The mean MSV on the ipsilateral and contralateral sides of the NSD was 21.50 ± 3.84 cm3 and 22.10 ± 3.56 cm3, respectively; thus, NSD did not affect MSV (p = 0.150). The mean MSV on the edentulous and non-edentulous sides was 21.58 ± 3.89 cm3 and 21.77 ± 4.30 cm3, respectively; thus, the MSV was significantly smaller on the edentulous side (p = 0.00036).ConclusionAlthough this study was a limited preoperative study, three-dimensional measurement of the maxillary sinus with CBCT in partially edentulous patients revealed that missing teeth lead to substantial reductions in MSV, while NSD was not associated with MSV.

Platelet-rich plasma in maxillary sinus augmentation, direct maxillary sinus floor augmentation

The placement of endosseous implants in posterior edentulous maxilla is normally a challenging task in implant dentistry due to maxillary sinus pneumatization. Various sinus augmentation techniques have been used with impressive success rates aimed at developing these sites for implant placement. Knowledge of anatomy of maxillary sinus guides us not only in proper preoperative treatment planning but also helps us to avoid the possible complications that may arise during sinus augmentation procedure. This topic attracts a rising number of publications with most of them reporting results that suggest, the patients with atrophic maxilla requiring implant treatment can benefit considerably from the use of sinus augmentation. This article explains the basic technique namely direct techniques used for maxillary sinus elevation and augmentation.

Research progress on application of concentrated growth factors in maxillary sinus augmentation and sinus mucosal repair

Research progress on application of concentrated growth factors in maxillary sinus augmentation and sinus mucosal repair

Does new bone formation vary in different sites within the same maxillary sinus after lateral augmentation? A prospective histomorphometric study.

ObjectiveThe aim of this study was to evaluate histomorphometric outcomes of lateral maxillary sinus augmentation in different areas of the same cavity and to correlate results to bucco‐palatal sinus width (SW) and residual bone height (RBH).Material and MethodsPatients needing maxillary sinus floor elevation (RBH <5 mm) to insert two nonadjacent implants were treated with lateral augmentation using a composite graft. Six months later, two bone‐core biopsies (mesial/distal) were retrieved in implant insertion sites. SW and RBH were measured on cone beam computed tomography, and correlations between histomorphometric and anatomical parameters were evaluated by multivariate linear regression analysis.ResultsTwenty patients underwent sinus augmentation, and eighteen were included in the final analysis (two dropouts for membrane perforation). Mean newly formed mineralized tissue percentage (%NFMT) after 6 months in mesial and distal sites was 17.5 ± 4.7 and 11.6 ± 4.7, respectively (p = .0004). Multivariate linear regression showed a strong negative correlation between SW and %NFMT (β coefficient=−.774, p < .0001) and no correlation between RBH and %NFMT (β coefficient =−.038, p = .825).ConclusionsThe present study confirms that %NFMT after lateral sinus augmentation occurs at different rates in different anatomical areas of the same maxillary sinus, showing a strong negative correlation with SW, whereas no influence of RBH was observed. Clinicians should regard SW as a guide for graft selection and to decide duration of the healing period. Researchers should consider SW as a predictor variable, when comparing regenerative outcomes of different biomaterials by using maxillary sinus as an experimental model.

Long-Term Human Histologic Evaluation of Sinus Bone Augmentation and Simultaneous Implant Placement.

This study aimed to histologically and histomorphometrically evaluate osseointegration following simultaneous implant placement and maxillary sinus augmentation. Three retrospective human cases are described in which implants were placed at the maxillary sinus site augmented with deproteinized bovine bone mineral (DBBM) and later retrieved due to implant fracture after 5 to 8 years of occlusal loading. The removed implants with bone were processed for histologic evaluation, and bone-to-implant contact (BIC), bone area (BA), and mirror-image bone area (MIBA) were measured. Mature lamella bone was mainly observed, and some unabsorbed grafted bone particles remained in all cases. The measured values of BIC, BA, and MIBA in the three consecutive threads with the highest values were 86.0% to 91.2%, 65.8% to 91.9%, and 73.0% to 90.4%, respectively, and there were no signs of inflammation. Within the limits of this study, these cases demonstrate successful bone formation after maxillary sinus bone augmentation with DBBM and simultaneous implant placement.

Retrospective Analysis of Risk Factors Related Implant Loss in Patients with Maxillary Sinus Augmentation and Simultaneous Implant Placement

Retrospective Analysis of Risk Factors Related Implant Loss in Patients with Maxillary Sinus Augmentation and Simultaneous Implant Placement

口腔インプラント治療による上顎洞炎の治療

Two hypotheses have been proposed for the pathogenesis of maxillary sinusitis caused by dental implant placement and/or maxillary sinus augmentation surgery.

上顎洞底挙上術による上顎洞炎の病態と治療

上顎洞底挙上術による上顎洞炎の病態と治療

Shape-Memory ECM-Mimicking Heparin-Modified Nanofibrous Gelatin Scaffold for Enhanced Bone Regeneration in Sinus Augmentation.

Biomaterials with clinical maneuverability and predictable bone regeneration are needed in the field of maxillary sinus augmentation. Herein, gelatin was chemically modified with heparin that specifically interacted with and stabilized bone morphogenetic protein-2 (BMP-2). We then introduced thermally induced phase separation to form the injectable, shape-memory, highly porous scaffold for bone regeneration in sinus augmentation. The hydrated heparin-modified nanofibrous gelatin scaffolds (NH-GS) were demonstrated with high resilience and shape-memory property, both macroscopically and microscopically, making them injectable scaffolds and expected to be applied in sinus augmentation. This novel scaffold was verified to be biocompatible and an excellent matrix to support cell attachment, proliferation, and infiltration. Further, the growth factor-loaded NH-GS showed sustained release kinetics of BMP-2 through affinity-based scaffold-growth factor interaction, compared with BMP-2 loaded gelatin sponge (GS) and nanofibrous gelatin scaffold (NF). Both in vitro and in vivo experiments demonstrated that the BMP-2-loaded NH-GS exhibited the highest osteogenesis among the other groups. Taken together, this study introduces a new regenerative strategy in maxillary sinus augmentation, which is injectable with a predefined shape and structure and promotes bone regeneration through a more sustained BMP-2 release.

Sinus Mucosa Thinning and Perforations after Sinus Lifting Performed with Different Xenografts: A Histological Analysis in Rabbits

Background: Experimental studies have shown a progressive thinning and perforations of the sinus mucosa associated with sharpened edges and the cutting projections of graft particles used simultaneously for maxillary sinus augmentation. Hence, the aim of the present study was to evaluate the damaging effects of two different bovine grafts on the sinus mucosa after sinus augmentation. Methods: Twenty New Zealand rabbits received a bilateral sinus lifting using, as fillers, two different types of deproteinized bovine bone in granules, one processed at low temperature (low-T group), and the other at high temperature (high-T group). Thinned mucosa sites (<40 µm) and perforations were evaluated in the sinus mucosa that were in contact with graft granules after 2 and 10 weeks, in ten animals per period. Results: After 2 weeks of healing, the number of thinned mucosa sites was 118 in the low-T group, and 149 in the high-T group (p = 0.191). At the 10-week assessment, the thinned sites increased to 237 and 195 sites, respectively. The numbers of sinus mucosa perforations after 2 weeks were eight and three in the low-T and high-T group, respectively. At the 10-week evaluation, the perforations increased to 19 in the low-T group, and to 14 in the high-T group. Conclusions: The contact with bovine xenografts yielded thinning and perforations of the sinus mucosa. Despite the differences in characteristics and dimensions, no differences were found between the two xenografts in the numbers of thinning mucosa sites and perforations. However, a trend of more events was found in the low-T compared to the high-T group.

Rehabilitation of Maxillary Posterior Edentulism with Direct Antroplasty and Dental Implants: A comparative analysis of two different types of bone grafts

Aims - To determine the difference in the amount of bone generated from two different sites for bilateral maxillary sinus augmentation. Introduction-Rehabilitation of the edentulous posterior maxilla with an implant supported prosthesis is a commonly occurring challenge in dental practice. Objectives - Achieving adequate height of alveolar bone for placing dental implants requires uplifting of the sinus lining in many such cases. This is generally done by harvesting bone grafts from various sites and placing it in the defect created after raising the sinus lining thus restoring the height and width of residual alveolar bone. Objectives - To determine if regional sites of bone graft harvest are equally effective when compared with distant site. Material &amp; Methods - In this series, out of 3 of our patients, two received autologous chin grafts and one patient received PCBM graft from the iliac crest. In all 3 patients, implants were placed in the second stage. Results -Acomparative analysis of the feasibility of the two techniques which involves bone grafts from two sites which have different quality of bone available over the end outcome was done and it was found that the quality of bone available for implant placement was almost the same irrespective of the graft harvest site. Conclusion - It can be safely concluded chin graft is a viable alternative to cortico-cancellous bone graft in cases of direct sinus lift procedures with minimal issues of donor site morbidity.

Removal of Inflammatory Tissue/Product by Sinus Membrane Puncturing during Lateral Sinus Augmentation in Asymptomatic Patients with Severely Opacified Sinuses: A Case Series

It is generally recommended that severe sinus membrane (SM) thickening should be treated prior to maxillary sinus augmentation (MSA), but during lateral MSA, inflammatory tissue/product may be removed by puncturing the SM. The present case report demonstrates surgical experience of lateral MSA with simultaneous inflammatory tissue/product removal for sinuses with severe opacification. In three patients requiring dental implant placement in the posterior maxilla, severe SM thickening was observed, but they were asymptomatic. The SM was gently elevated, followed by puncturing the SM, removing inflammatory tissue via the punctured site, draining, and thorough saline irrigation. Then, bone grafting and implant placement were performed with extra care not to spread bone substitute material into the punctured area. The postoperative pain following this procedure was more severe as compared to conventional MSA. Nasal bleeding was reported for 2–3 days. All implants were successfully integrated and demonstrated adequate function. Tissue samples retrieved during the surgery showed advanced inflammatory cell infiltration. The follow-up cone-beam computed tomographic scans revealed a significant reduction in SM thickening. In conclusion, inflammatory tissue/product removal by puncturing the SM can be applied during lateral MSA. However, more data should be needed due to the empirical nature of the present outcomes.

Changes in bone graft height and influencing factors after sinus floor augmentation by using the lateral window approach: A clinical retrospective study of 1 to 2 years

Statement of problemRecent systematic reviews have reported resorption of bone grafts after augmentation, but the influencing factors are numerous and uncertain. Different brands of bone graft and other factors may affect the bone formation effect after sinus floor augmentation. PurposeThe purpose of this retrospective clinical study was to evaluate the graft material height changes after sinus floor augmentation with cone beam computed tomography (CBCT) and to investigate the potential influencing factors related to graft resorption. Material and methodsFour midsagittal cut CBCT images of 157 posterior maxillary implants after maxillary sinus floor elevation by using the lateral window approach with bone grafts from 116 patients were obtained. Four CBCT scans had been performed immediately (T0), 6 months (T1) and 12 months after bone grafting (T2), and 1.5 to 2 years after treatment (T3), and the distance between the implant platform and the grafted mucosa of the maxillary sinus floor was measured at 3 locations. Correlation coefficients of these parameters were calculated. A linear mixed model was used to investigate potential factors influencing graft height reduction, including the patient's sex, age, smoking status, periodontal status, graft brand, implant site, implant level, placement time, and residual bone height. ResultsMean ±standard deviation graft height at the mesial side of the implant (MeGH) was significantly decreased by 0.32 ±0.88 mm in the first 6 months, was gradually reduced after 6 months (0.26 ±0.43 mm), and then 1 to 2 years later increased to 0.39 ±0.97 mm. The changes in graft height at the center of the implant (CeGH) and graft height at the distal side (DiGH) groups were similar to those in the MeGH group. A significantly positive correlation was found among the height alterations in 3 locations (rs=0.954, P<.001). The linear mixed model showed that smoking was more likely to cause graft height reduction in MeGH (P=.034). ConclusionsGraft height significantly decreased after maxillary sinus augmentation over 1 to 2 years. Smoking had a negative effect on graft height changes, while the 2 brands of graft and other factors had no significant effect.

Polymeric Scaffolds for Dental, Oral, and Craniofacial Regenerative Medicine

Dental, oral, and craniofacial (DOC) regenerative medicine aims to repair or regenerate DOC tissues including teeth, dental pulp, periodontal tissues, salivary gland, temporomandibular joint (TMJ), hard (bone, cartilage), and soft (muscle, nerve, skin) tissues of the craniofacial complex. Polymeric materials have a broad range of applications in biomedical engineering and regenerative medicine functioning as tissue engineering scaffolds, carriers for cell-based therapies, and biomedical devices for delivery of drugs and biologics. The focus of this review is to discuss the properties and clinical indications of polymeric scaffold materials and extracellular matrix technologies for DOC regenerative medicine. More specifically, this review outlines the key properties, advantages and drawbacks of natural polymers including alginate, cellulose, chitosan, silk, collagen, gelatin, fibrin, laminin, decellularized extracellular matrix, and hyaluronic acid, as well as synthetic polymers including polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), poly (ethylene glycol) (PEG), and Zwitterionic polymers. This review highlights key clinical applications of polymeric scaffolding materials to repair and/or regenerate various DOC tissues. Particularly, polymeric materials used in clinical procedures are discussed including alveolar ridge preservation, vertical and horizontal ridge augmentation, maxillary sinus augmentation, TMJ reconstruction, periodontal regeneration, periodontal/peri-implant plastic surgery, regenerative endodontics. In addition, polymeric scaffolds application in whole tooth and salivary gland regeneration are discussed.

Late Developed Unusual Nasal Involvement of Postoperative Maxillary Cyst Following Maxillary Sinus Augmentation: A Case Report

Postoperative maxillary cyst (POMC) is a benign expansive cystic lesion of the maxilla generally related to invasive maxillary surgeries or trauma. POMC can also develop after maxillary sinus augmentation (MSA), but many dentists are not well-aware of such complication of MSA. A 56-year-old male patient had undergone bilateral MSA. After 18 years, the patient reported painless swelling on the left palate. On the panoramic radiographs, no specific findings were found, but a large unilocular lesion was detected at the medial side of the previous augmentation of the left maxillary sinus on cone-beam computed tomographic examination. The lesion expanded medially and downward to destruct the medial wall of the maxillary sinus and palatal bone. Medial expansion of the lesion also reached the nasal septum and inferior meatus. Due to the extent and the location, the lesion was hard to manage using an intraoral surgical approach. The patient was then referred to an otolaryngologist in a university hospital. Endoscopic marsupialization was performed under general anesthesia. Previous augmentation and dental implants could be maintained during the marsupialization. The removed tissue sample revealed respiratory epithelium with inflammatory cell infiltration, confirming that the lesion was a postoperative maxillary cyst (POMC). There has been no recurrence of POMC to date. POMC is a rare postoperative complication of maxillary sinus augmentation, but clinicians should be aware of the possibility of POMC and the necessity of regular radiological monitoring.