The Importance of Maxillary Sinuses in Oral and Maxillofacial Surgical Procedures

Abstract

Oral and maxillofacial surgical procedures, such as tooth extractions, surgical treatment of odontogenic maxillary sinus pathologies, dental implant surgery, orthognathic surgery, and sinus lift procedures, often correlate with the maxillary sinuses, due to anatomical proximity. For instance, in Le Fort I osteotomy, which is the predominant surgical technique preferred for the treatment of dentofacial deformities of the maxilla, the osteotomy line includes maxillary sinus and nasal walls. Maxillary sinus-lifting surgery is performed to regenerate bone in the posterior maxilla for dental implant placement. Additionally, maxillary sinus pathologies of odontogenic origin, such as sinusitis, cysts, and neoplasms, can impact the oral and maxillofacial region, and surgical intervention may be required to manage these conditions. Proper diagnosis, treatment planning, and surgical techniques are essential to optimize patient outcomes and minimize complications related to the maxillary sinuses in oral and maxillofacial surgical procedures.

1. Introduction

The maxillary sinus plays an essential role in the oral and maxillofacial surgery, serving as a complex anatomical structure that closely interacts with the surrounding oral and facial regions. Understanding the importance of the maxillary sinuses is important, as it directly influences the diagnosis, treatment planning, and surgical outcomes in a variety of procedures.

This chapter investigates the significance of the maxillary sinuses in oral and maxillofacial surgery, focusing on the complications and their clinical implications. With detailed explanations on the management of these complications, it is aimed to provide a comprehensive understanding of the maxillary sinuses’ role and impact on oral and maxillofacial surgical interventions. This encompasses their involvement in tooth extraction, sinus-lifting surgery, orthognathic surgery, management of odontogenic infections, and the treatment of antral pathologies.

By synthesizing the current literature and incorporating clinical experiences and insights, this chapter aims to serve as a comprehensive resource for the complication management of maxillary sinus origin in oral and maxillofacial surgical procedures, thus giving surgeons insight on the subject to perform more successful treatments.

2. Preoperative radiological evaluation of maxillary sinuses

Radiologic evaluation of the maxillary sinuses plays a critical role in oral and maxillofacial surgery. Accurate imaging and evaluation of the maxillary sinuses is essential for effective treatment planning. By understanding the principles and techniques of radiologic evaluation, surgeons can optimize surgical outcomes and improve patient care.

2.1 Normal appearance of the maxillary sinuses on conventional radiographs

The maxillary sinuses are observed radiographically as bilateral radiolucent cavities in the maxilla, with well-defined, dense, and corticated radiopaque margins. The internal bony septa and blood vessel canals in the walls can be observed. The thin epithelial lining is usually not visible.

Oral and maxillofacial surgeons should have knowledge on:

• The radiological anatomy of the sinuses, including their shape, size, normal variations, and related structures.

• How the maxillary sinuses are represented normally on conventional radiographs, and how these radiographs are assessed.

• The radiographic features of pathologic conditions.

2.2 Maxillary sinus imaging modalities

The maxillary sinuses can often be observed on conventional dental radiographs such as periapical radiographs, upper occlusal radiographs, and orthopantomograms (OPTGs) as well as cranial imaging techniques such as Water’s, Caldwell, lateral sinus, and submentovertex radiographs. However, it is not possible to reveal small changes or examine the maxillary sinuses in depth with these methods [1].

Today, the imaging methods of choice for the investigation of possible pathologies and surgical planning in the maxillary sinus are CT (computed tomography imaging), CBCT (cone beam CT), and MR (magnetic resonance imaging).

2.3 Conventional computed tomography

CT applications in the head and neck region allow the evaluation of inflammation, cysts, and benign and malignant tumors with multiplanar imaging and 3D reconstruction of normal and abnormal hard and soft tissues. Conventional CT provides detailed visualization of the nasal cavity, lateral nasal wall, osteomeatal unit and sinuses [2, 3].

Computed tomography (CT) offers numerous advantages compared to traditional imaging techniques. Firstly, CT enables the visualization of the structure under examination without the interference of surrounding tissues, thereby providing a clearer view. Additionally, CT provides high contrast resolution, facilitating the differentiation of tissues with varying physical densities. This feature allows for easier separation and identification of different tissues. Moreover, CT allows for the visualization of tissues in axial, coronal, and sagittal planes, providing a comprehensive understanding of the examined area. Furthermore, CT eliminates distortion and magnification, ensuring accurate representation of the imaged structures. Lastly, CT enables the determination of the nature of lesions by measuring their density, particularly in the presence of cysts or tumors, thereby distinguishing between solid and liquid structures [4, 5].

However, there are disadvantages such as the need for contrast media for visualization of soft tissues, more radiation compared to conventional methods, and deterioration of image quality due to scattering of metallic objects in the image. Also, CT has limited use due to its high cost, lack of easy access, and high radiation dose to patient [5].

Cone-beam computed tomography: due to the disadvantages of the CT imaging, CBCT imaging has been manufactured. This modality can be used in oral and maxillofacial region, with less radiation to obtain 3D images without spatial distortions related to the shapes of the X-ray beams used in conventional computed tomographies while having almost all the superiorities of the CT over conventional imaging techniques [6, 7]. Unlike the multiple rotations used for image acquisition in CT, a single 360° rotation is sufficient for imaging the area of interest in CBCT [8]; this allows for more efficient use of X-rays, requires much less electricity, and provides a three-dimensional image with less cost while taking up less space [9].

CBCT also shows a superior spatial resolution to that of CT due to the conical shape of used beams. However, CT shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The superior spatial resolution of CBCT is helpful in planning surgery with accuracy.

Magnetic resonance imaging: In the oromaxillofacial region, MRI is mostly used for the radiological examination of the TMJ disc, structure, and pathologies; however, it is also the most successful imaging method preferred for the examination of tumors in the paranasal sinus region, determining the local invasion of these tumors and evaluating cysts [10].

The signals generated in MRI are related not only to the physical properties of the tissue, as in CT, but also to its biochemical composition. Therefore, it has been used for the identification and characterization of pathologies. Another advantage is that blood vessels can be visualized, and the direction and velocity of blood flow can be determined without the need for contrast agent injection [11]. MRI provides more soft tissue contrast, tissue differences, and definition of marginal lesions [2, 12, 13]. MRI is also useful in differentiating between infections of different origin in the sinonasal region; bacterial and viral infections cause high signal intensity on T2-weighted images, whereas fungal infections either cause no signal or show signal intensity similar to air [3].

MRI is also extremely helpful in the diagnosis of neoplastic and inflammatory pathologies. Many inflammatory diseases have hyperintense signal characteristics on T2-weighted images. On the other hand, it is notable that the majority of tumors have moderate signal intensities when observed on T2-weighted imaging [3]. MRI is also used in the evaluation of regional and intracranial complications of inflammatory sinus diseases and in the identification and staging of neoplastic pathologies [12].

The most important disadvantage of MRI is that the anatomical relationship of the paranasal sinuses and drainage tracts cannot be determined because the cortical bone cannot be monitored [12].

2.4 Radiographical imaging of the maxillary sinus pathologies

Inflammation of the membranes of the paranasal sinuses is called “sinusitis”. Since the nasal and paranasal sinus mucosa have a similar structure, they are affected at approximately the same time, so “rhinosinusitis” is the more appropriate term. There are several symptoms such as nasal congestion, obstruction, congestion, nasal discharge, facial pain or pressure, and reduced sense of smell in patients with rhinosinusitis. Fluid accumulation or opacification of the sinuses on radiographs may be present. However, the diagnosis of sinusitis cannot be made based on radiographic findings alone, as some asymptomatic patients may develop minor mucosal thickening, which has no clinical significance [14].

Anatomical variations that affect the drainage of the maxillary sinus include Haller (infraorbital ethmoid air) cell, turbinate bullae, uncinate bullae, and deviations of the nasal septum and bone bridges in the nasal septum. Although many studies have found that anatomical variations are more common in patients with maxillary sinusitis, no statistically significant relationship between the two has been found [15, 16]. However, the coexistence of anatomical variations may affect the drainage of the maxillary sinus and cause sinusitis [17].

Haller cells negatively affect sinus ventilation and are associated with sinusitis depending on the degree and size of pneumatization. Larger Haller cells are associated with maxillary sinus mucosal pathology due to the resulting narrowing of osteomeatal complexes [17, 18].

The mucosa of the maxillary sinus is typically observed as a thin and smooth soft tissue density located peripherally on the inner walls of the sinus. A mucosal thickness above 2–3 mm is commonly regarded an indication of pathological states. The thickness of mucosa in males is greater than that in females. There is also a gradual decrease in mucosal thickness from the anterior to the posterior region [19]. The presence of increased thickness of the mucosal lining in the lower region of the maxillary sinus is commonly associated with dental pathology or prior surgical interventions. Numerous studies have identified periapical inflammation as the most common cause of inflammation of the maxillary sinus mucosa, followed by severe periodontitis, oroantral connections or fistulae, and surgical procedures that contribute to perforation and inflammation of the maxillary sinus mucosa [20].

Radiologically, orthopantomograms and periapical radiographs are helpful in the evaluation of pseudocysts, the degree of pneumatization of the sinus, the relationship between the maxillary teeth and the sinus, and the identification of foreign bodies, roots, or teeth in the sinus [21, 22]. CT is the gold standard for imaging the bone and soft tissue of the maxillary sinus because it allows three-dimensional imaging in many planes; in axial and coronal planes, the relationship between the periapical odontogenic abscess and the defect in the sinus floor can be examined [21, 23]. CBCT can be used to determine the relationship between the sinus and dental pathology and to reveal the etiology of sinusitis [24].

2.5 The significance of radiologic evaluation of the maxillary sinus in treatment planning

A thorough understanding of anatomy and normal variations of maxilla and surrounding structures is essential to evaluate the preoperative CT images, which serve as the basis for the surgical plan [25]. Accurate assessment of the maxillary sinus through radiographic imaging provides information used in comprehensive treatment planning, improves surgical outcomes, and minimizes potential complications.

The gold standard for diagnosing and characterizing maxillary sinus pathologies is cone-beam computed tomography (CBCT); identifying these is very important as these can alter treatment decisions, such as dental implant placement, orthognathic surgery, and maxillofacial reconstructions. This also allows for preoperative identification of factors that may increase the risk of maxillary sinus-related complications, such as thinning of the sinus floor, the presence of antral septa, or proximity to vital structures.

Radiographic imaging provides information about the dimensions of the remaining alveolar ridge, the presence of sinus septa, and the proximity of the sinus floor to potential implant sites in dental implant surgery and sinus-lifting surgery. This information guides the development of treatment plans that ensure successful implant surgery while preserving the integrity of the sinus. Accurate radiologic assessment aids in selecting the most appropriate implant length, diameter, and angulation, thereby reducing the risk of sinus complications and achieving predictable treatment outcomes.

Radiological evaluation also plays an important role in the treatment planning of maxillofacial tumors, odontogenic cysts, and infections that extend into the maxillary sinus. This allows the surgeon to accurately assess the size and nature of these pathologies and to determine the most suitable surgical approach. By visualizing how the pathology relates to nearby anatomical structures, radiographic evaluation optimizes surgical procedures, reduces the chances of complications, and ensures effective removal or treatment of the underlying issue.

3. Oral and maxillofacial surgical procedures involving the maxillary sinuses

3.1 Odontogenic maxillary sinusitis

Maxillary sinusitis refers to the inflammatory condition affecting the maxillary sinus, which can arise from several etiologies such as viral, bacterial, allergic, or fungal rhinitis [26]. Nevertheless, the presence of any pathology in the dentoalveolar region of the posterior maxilla has the potential to impact the floor of the maxillary sinus, resulting in a condition known as odontogenic maxillary sinusitis (OMS). Odontogenic maxillary sinusitis (OMS) is a frequently occurring kind of sinusitis that requires a specialized therapeutic approach distinct from non-odontogenic maxillary sinusitis [23].

Etiology: Dentoalveolar surgery or odontogenic infection resulting in perforation of the maxillary sinus floor and Schneiderian membrane in the posterior maxilla is the prevailing cause of odontogenic maxillary sinusitis [27]. OMS can potentially arise from various sources, including an oroantral fistula, periapical and periodontal conditions such as apical periodontitis and marginal periodontitis, dental trauma, iatrogenic factors such as impacted tooth extractions, dental implants, sinus lift surgery, the inadvertent extrusion of endodontic materials into the sinus, as well as maxillary osteotomy in orthognathic surgery. The first molar (35.6%), second molar (22%), third molar (17.4%), and second premolar (14.4%) are the maxillary teeth that are most commonly affected. Oroantral fistula (OAF) is the prevailing etiology of odontogenic maxillary sinusitis following tooth extraction [28].

The primary symptoms of OMS encompass facial discomfort or pressure in the region of the cheek, nasal blockage, one-sided discharge of purulent mucus from the nose, perception of unpleasant odors (cacosmia), and the drainage of mucus from the back of the nasal cavity. Nevertheless, these symptoms lack the ability to differentiate OMS from alternative etiologies of sinusitis. While many individuals diagnosed with OMS may exhibit symptoms such as dental pain and nasal congestion, others may only suffer mild sinusitis symptoms and tooth pain. This discrepancy arises from the unobstructed state of the maxillary sinus ostium, which facilitates the drainage process and therefore alleviates pressure [21, 26, 29].

It is important to note that a minority of patients who exhibit orofacial OMS report having undergone a dental operation in the recent past [29]. OMS may manifest within a year following dental surgery with graft infection or after a latency period of nearly 4 years as a delayed consequence of implant surgery caused by increasing peri-implantitis [30]. As a result, recent dental procedure is not a definitive criterion for the diagnosis of iatrogenic OMS.

The diagnosis of OMS should be predicated upon a comprehensive dental and medical evaluation. Patients’ maxillary sinus-related symptoms and dental history, such as past tooth extractions from the posterior maxilla or sinus lift procedures, should be fully learned [31].

The examination of the buccal mucosa and vestibule is necessary to assess for the presence of any signs of edema or erythema. Furthermore, it is imperative to do vitality testing, percussion, and palpation on the posterior teeth in order to ascertain their vitality. The evaluation of the maxillary sinus can also be conducted through intranasal examination using anterior rhinoscopy or flexible nasolaryngoscopy [31].

Oral antral communications (OAC) and oroantral fistulas (OAF) can typically be diagnosed through intraoral examination, the Valsalva maneuver, or by inspecting the extraction site using a blunt probe [32]. Purulent discharge may be present from the OAF.

Radiographic imaging is of paramount importance in the identification and management of OMS. Periapical and panoramic radiography are valuable tools for evaluating the dimensions of periapical lesions and visualizing various diseases, root irregularities, dental problems, and foreign body displacements occurring in the maxillary sinus [33]. It is imperative to acknowledge that the radiographs under consideration are constrained to two-dimensional imaging. As a result, these methods may not offer a thorough assessment of the maxillary sinus in comparison to alternative imaging modalities [29, 33, 34]. Computerized tomography (CT) is widely regarded as the preferred method for imaging the maxillary sinus, primarily due to its exceptional resolution and comprehensive assessment of the sinus in three dimensions.

In the treatment of OMS, antibiotic therapy should be given; amoxicillin in combination with clavulanate should be preferred initially [35, 36, 37]. Alternative medications in case of penicillin allergy are piperacillin, cefotaxime, cefuroxime, clindamycin, moxifloxacin, ciprofloxacin, and tetracyclines [35].

There is currently no recognized management regimen for the future therapy of OMS. However, it has been seen that both oral surgery and endoscopic sinus surgery (ESS) yield favorable outcomes [29, 38]. In cases where there is unequivocal evidence of dental etiology, the appropriate management of dental pathology entails the implementation of endodontic therapy, apical resection, or tooth extraction [29].

When symptoms persist, especially if the maxillary sinus ostium is blocked or the height of the thickened mucosa passes the half of the maxillary sinus, endoscopic sinus surgery is recommended [39, 40]. The Caldwell-Luc procedure presents a greater incidence of intraoperative complications such as bleeding, face edema, and infraorbital nerve injury, as well as postoperative complications including oroantral fistula (OAF), tooth devitalization, and facial paresthesia [32].

The integration of ESS with dental surgery is often regarded as the optimal strategy, as it guarantees comprehensive eradication of the infection while also mitigating the risk of future relapses and associated problems [41, 42, 43]. However, the severity of the dental and sinonasal disease is also important; as patients with lower sinonasal burden can be cured with dental surgery alone, whereas individuals who have little dental disease may experience complete recovery just through the implementation of endoscopic sinus surgery (ESS) [37]. In any case, dental surgery should be considered the primary element of treatment due to the dental origin of the condition.

3.2 Odontogenic cysts involving the maxillary sinuses

Odontogenic cysts located in the maxilla are pathological conditions characterized by the destruction of bone tissue. Typically, these cysts do not exhibit any noticeable symptoms and are often discovered by chance during normal dental examinations with the use of radiographic imaging [44]. In general, enucleation is the preferred method of treatment for these cysts; yet there is a possibility for their expansion to extend into the maxillary sinus cavity. Various treatment modalities are available for managing large maxillary odontogenic cysts, including segmental excision, decompression, enucleation, marsupialization, and transnasal endoscopic sinus surgery. Although segmental resection has the advantage of free margin excision, it is associated with significant morbidity, such as the loss of dentition and cosmetic deformities. Additionally, this technique necessitates a reconstructive treatment including either a prosthesis or a free flap.

The most common odontogenic cysts are radicular cyst, dentigerous cyst, and odontogenic keratocyst, respectively. The mentioned lesions have the potential to reach significant dimensions, leading to total involvement of the maxillary sinus and subsequent impact on the walls of the maxillary sinus, orbital floor, and neighboring teeth. The presence of sizable inflammatory cysts has the potential to induce further inflammation and infection within the maxillary sinus.

The formulation of treatment plans for individuals with large odontogenic cysts that extend into the maxillary sinus, as well as those with subsequent chronic maxillary sinusitis, necessitates the involvement of both oral and maxillofacial surgery and otorhinolaryngology disciplines. Invasive techniques encompass several surgical approaches such as segmental or marginal excision of the jaw, enucleation with curettage, and enucleation with the application of Carnoy’s solution or cryotherapy. Nevertheless, when dealing with substantial cysts that affect crucial anatomical structures, a more cautious approach is necessary. This approach typically involves decompression or marsupialization, followed by the removal of the cyst with enucleation [45, 46].

Invasive procedures exhibit a reduced likelihood of recurrence, albeit at the expense of elevated morbidity, which encompasses the loss of affected teeth, oroantral communication, chronic sinusitis, and the necessity for comprehensive reconstruction. These procedures require a surgical incision within the oral cavity, removal of teeth, and excision of the cyst walls. The utilization of transoral techniques is associated with several adverse effects, including the extraction of both impacted and adjacent teeth, the occurrence of oroantral communication, the development of chronic sinusitis, and the requirement for reconstructive procedures to address maxillary bone defects.

The utilization of a transnasal endoscopic approach has been proposed as a viable alternative method with less morbidity for the removal or marsupialization of large cysts. Additionally, this strategy can be employed to attain osteomeatal complex patency in instances of chronic sinusitis. The surgical treatment entails the execution of an inferior meatal antrostomy by raising a mucosal flap from the medial maxillary wall, which is situated to the side of the inferior turbinate, and subsequently forming an opening in the bony wall. The cyst is dissected using surgical means and subsequently extracted, while the mucosal flap is repositioned to ensure adequate coverage of the maxillary sinus floor. The elimination of cyst walls is also observed. By making modifications to the methods, it becomes feasible to maintain the presence of the inferior turbinate, thus guaranteeing the preservation of normal physiological functioning.

The transnasal endoscopic approach offers several advantages in comparison to other methods. These include the ability to prevent the need for substantial tooth extraction and the subsequent risk of oroantral communication. Additionally, this strategy eliminates the need for transoral incisions, reducing the likelihood of postoperative cheek swelling. Furthermore, it allows for effective marsupialization of remains into the maxillary sinus cavity, ensuring thorough removal. The integration of functional endoscopic sinus surgery with intraoral therapy for smaller cysts accompanied by secondary sinusitis is also a viable approach. The utilization of a simultaneous transnasal endoscopic approach in conjunction with oroantral communication repair has been found to be a reliable and effective surgical intervention for the closure of sizable oroantral fistulas and the management of secondary sinus illness [47].

3.3 Tooth extractions and oroantral communication/fistula

Extractions of the maxillary posterior teeth may result in communication (OAC) between the oral cavity and the maxillary sinus when the maxillary sinus is greatly pneumatized, the residual alveolar ridge height is minimum between the apices and the maxillary sinus floor, and the roots of the tooth are widely divergent. Management is necessary to prevent further complications. The two most problematic complications are postoperative odontogenic maxillary sinusitis and formation of an oroantral fistula (OAF); the probabilities of these two complications depend on the size of the oroantral communication and the management of the sinus exposure [48].

Prevention is the easiest and most efficient method of managing this situation. Detailed preoperative radiographic evaluation must be performed between the root apices and the maxillary sinus floor before the extraction of the maxillary posterior teeth. In cases where the sinus floor is in close proximity to the tooth roots exhibiting exhibit significant divergence, it is advisable for the surgeon to do a surgical extraction procedure involving the sectioning of the tooth roots. Excessive force in the apical direction should be avoided in the extraction of these maxillary molars.

An oroantral communication can be diagnosed with several methods. The first is to examine the tooth after the extraction. If there is a section of bone adhered to the apices of the tooth, it should be assumed that a communication between the maxillary sinus and the oral cavity exists. The Valsalva maneuver can be utilized by providing instructions to the patient to exert gentle pressure to release air against closed nostrils while maintaining an open mouth. The presence of air or blood flow at the postoperative site typically signifies the existence of an aperture. The presence of fogging on a mirror positioned at the aperture can also serve to confirm the diagnosis. However, if there is no communication, forceful blowing has the risk of creating a communication. Therefore, excessive force must be avoided when performing the Valsalva maneuver [48].

3.3.1 Treatment options for oroantral communications and oroantral fistulae

Decisions about the treatment of the OAC/OAF are determined by several factors, including the dimensions of the opening, the timing of the diagnosis, the presence of sinus infection, and the quantity and quality of tissue suitable for surgical repair [49]. An oroantral communication should be closed within 24 hours; the longer the communication persists, the more likely it is to transform to an oroantral fistula [50].

After an oroantral communication has been diagnosed, approximate size of the communication must be guessed because the treatment depends on the size of the opening. Nevertheless, it is advisable to refrain from probing, as probing a small aperture has the potential to end up in its enlargement. If there is no osseous attachment to the dental structure, it is likely that the communication has a diameter of 2 mm or smaller. Nevertheless, if a significantly big bone fragment is removed with the tooth, it might be concluded that the resulting opening is of considerable dimensions [48].

If the diameter of the communication is equal to or less than 2 mm, there is no need for any supplementary surgical intervention. It is imperative to ensure the formation of a blood clot of optimal quality within the socket. Patients are encouraged to adhere to sinus precautions in order to mitigate the risk of dislodging the blood clot. Most OACs can close spontaneously if the diameter is less than 2 mm in healthy patients [51].

It is advisable to adhere to sinus precautions in order to mitigate alterations in the air pressure of the maxillary sinus, which could potentially lead to the displacement of the clot. It is recommended that patients be instructed to refrain from activities such as forcefully blowing their nose, sneezing with excessive force, using straws for suction, and smoking [51].

If the size of the opening is moderate (2–5 mm), additional measures should be taken. To help organize a blood clot in the area, clot-promoting substances such as a gelatin sponge should be placed in the socket and a figure-of-eight suture should be placed over the tooth socket. It is recommended that the patient adheres to the sinus precautions as well. Ultimately, it is recommended that the patient be administered a combination of many drugs in order to mitigate the likelihood of developing maxillary sinusitis. The recommended prescription for antibiotics, such as amoxicillin, cephalexin, or clindamycin, is a twice-daily dosage regimen for a duration of 5 days. Furthermore, it is recommended to provide a decongestant nasal spray in order to minimize the thickening of the nasal mucosa and ensure the patency of the ostium. If the ostium remains unobstructed and allows for regular sinus drainage, the probability of developing sinusitis will be reduced [51].

If the sinus opening is large (≥7 mm), the communication should be repaired with a flap procedure. The surgery should be performed the same day as the opening occurred for a favorable result to be obtained. The same sinus precautions and medications are usually required [51].

It is imperative to monitor the patient over a span of many weeks in order to promote successful healing. Patients who present with a little communication and no maxillary sinusitis upon returning within a few days typically experience spontaneous healing. Regular follow-ups are recommended to ensure that the communication does not persist.

3.3.2 Surgical repair of oroantral communications and oroantral fistula

Surgical intervention is recommended for the treatment of oroantral communications (OACs) or oroantral fistulas (OAFs) with a diameter above 7 mm, as such defects are unlikely to heal by spontaneous closure. There exist several alternatives for achieving closure: autogenous soft tissue grafts, autogenous bone grafts, allogeneic materials, xenografts, and synthetic closure techniques [50, 52, 53].

Maxillary sinusitis should be medically or surgically treated before the communication is repaired. All the granulation tissues must also be removed from the oroantral opening before attempting any definitive closure surgery.

3.3.2.1 Soft tissue flaps

3.3.2.1.1 Buccal advancement flap (Rehrmann technique)

The buccal advancement flap is the prevailing surgical technique employed for the closure of an oroantral connection. This strategy is commonly employed in the conclusion of communications that are of little to moderately sized nature.

Following the removal of the epithelized margins of the flaps to promote effective wound healing, two vertical releasing incisions are performed within the buccal vestibule. To ensure proper closure, it is recommended that the width of the flap be increased by 50% compared to the width of the opening. To achieve passive closure of the flap over the entrance, it is recommended to score the periosteum at a high level in the vestibule. A potential approach involves the utilization of a modified buccal advancement flap, wherein the buccal flap is secured beneath the elevated palatal flap to enhance the viability of the surrounding tissue.

The main disadvantage of this technique is the shallowing of the buccal vestibule [50, 54]. This has the potential to make the prosthetic treatment challenging in the future.

3.3.2.2 Buccal fat pad

The buccal fat pad (BFP) possesses a substantial vascular network, exhibits resistance to contraction, and consistently resides in close proximity to the potential communication location within the posterior maxilla. This procedure involves creating an incision in the mucosa located posteriorly to the zygomatic buttress. The procedure involves making an incision through the periosteum and the membrane that surrounds the BFP. The BFP is exposed with the utilization of Metzenbaum scissors during the process of blunt dissection. Subsequently, the buccal fat pad (BFP) is carefully inserted to encompass the aperture and secured with suturing to the mucosal borders.

The BFP exhibits a relatively low rate of failure, with the primary reason of failure being necrosis leading to the recurrence of an orocutaneous fistula [49, 55]. The occurrence of a depression in the cheek subsequent to the medical intervention has also been documented in scholarly sources. BFP is very technique sensitive and may not be successful in closing larger OACs; this technique is recommended for medium-size defects approximately 5 × 4 cm in size [51].

In cases where the BFP is not covered with gingival mucosa, complete epithelialization occurs in 2 weeks after the entire defect is entirely covered with BFP, which is sutured passively. Trismus is usually reported after reconstruction using the BFP.

3.3.2.3 Palatal flap

A palatal rotational flap is a technique used for large defects or a previous failed repair [56, 57]. The benefits of utilizing this particular flap can be listed as follows: a plentiful blood supply, the maintenance of the buccal vestibule, and the presence of keratinized mucosa for the purpose of reconstruction. The palatal flap exhibits greater thickness compared to the buccal mucosa, rendering it less susceptible to instances of rupture and tear.

It is advisable to employ this procedure for the closure of flaws above a size of 10 mm. The effectiveness of a palatal flap is contingent upon the establishment of an optimum length-to-width ratio.

The contraindications for this technique are previous palatoplasty and traumatic injury to the palate [56, 57]. It should also be kept in mind that smoking and coagulopathies can compromise the healing process of the palatal flap.

3.3.2.4 Tongue flap

In cases when the buccal and palatal flaps have proven ineffective and the size of the oroantral communication (OAC) exceeds 15 mm, a tongue flap may be employed as an alternative method of closure [53, 58]. Rich vascular supply and flexibility are the advantages of this technique; however, mobility of the tongue may cause failure due to its function in speaking and swallowing. Postoperative maxillomandibular fixation (MMF) is recommended to surpass this risk.

The modification of the flap design is determined by the specific characteristics of the opening, such as its position and size. In cases where abnormalities are present in the soft palate and posterior buccal mucosa, posterior-based tongue flaps are employed as a treatment method. The thickness of the flap typically varies between 3 and 5 mm, and its extent can range from approximately 1 cm away from the tip of the tongue to approximately 1 cm away from the circumvallate papilla. Following the elevation process, the tongue flap is surgically attached to the de-epithelized edges of the defect. The pedicle is severed 14–21 days after the first procedure to permit healing. A liquid diet is also recommended during this period.

The process may be limited by patient tolerance. There is a potential occurrence of postoperative tongue edema, which can lead to compromised airway function. In such cases, the administration of dexamethasone may be recommended as a therapeutic measure to mitigate tongue edema [53, 58, 59].

3.3.2.5 Other closure techniques

3.3.2.5.1 Buccal fat in a 3-layered closure

There are certain drawbacks associated with using soft tissue closure for an oroantral communication or fistula. When the defect is closed solely with soft tissue, it can create empty spaces where fluids can accumulate, leading to tension on the wound edges and potential reopening of the incision line. These fluids can also serve as a source of infection. On the other hand, utilizing a bone graft can serve as a supportive structure, preventing the sinus membrane from expanding towards the alveolar crest [60].

In this technique, a sulcular incision extending from the maxillary canine to the distal aspect of the second molar, accompanied by two vertical releasing incisions, is performed. The communication is carefully curetted, and a Caldwell-Luc window is prepared in the region of the canine-premolar teeth, located below the oroantral communication (OAC). This procedure is carried out with the aim of preserving the integrity of the surrounding bone. Subsequently, the bony window is removed and placed over the defect. The buccal fat pad is acquired and sutured in place. Lastly, a buccal advancement flap is performed as the final layer of the procedure [60].

3.3.2.5.2 The use of platelet-rich fibrin in a 3-layered closure

This approach involves the utilization of advanced platelet-rich fibrin (A-PRF), along with a buccal fat pad and a buccal advancement flap. In order to generate the A-PRF membranes, a volume of 20 mL of the patient’s blood is extracted and subsequently isolated from the red blood cell clots. The separated blood is then placed in a PRF box and pressed for 8 minutes. Using A-PRF membranes enhances the stability of the buccal fat pad and the buccal advancement flap and accelerates wound healing due to its local antibacterial properties. This is especially important for patients who exhibit poor wound healing. Once the granulation tissue and irregular bony margins are removed, the A-PRF membranes are applied to cover the defect. Subsequently, the buccal fat pad is strategically placed in order to effectively occlude the oroantral communication (OAC). Furthermore, it is necessary to create two vertical releasing incisions within the buccal vestibule in order to facilitate the full advancement of the buccal periosteum, thereby guaranteeing comprehensive coverage of the soft tissue [61].

3.3.2.5.3 Bone grafts

Bone grafts are utilized in the closure of bigger openings or in cases where soft tissue closure has been unsuccessful. The positioning of a bone graft has the potential to decrease the necessity for a subsequent sinus augmentation procedure. Bone grafts can be obtained from several anatomical locations, such as the anterior ramus, symphysis, maxillary tuberosity, and anterior iliac crest [49, 50].

The aforementioned methodology entails the utilization of bone grafts with the purpose of addressing bone deficiencies on the sinus floor. To obtain the graft, a spherical trephine bur that corresponds to the diameter of the bone defect is utilized. Following the placement of the graft on the defect, miniplates are employed to secure and stabilize the graft material. The closure of soft tissue is achieved through the utilization of a buccal advancement flap. It is advisable to have a sinus lift treatment concomitantly with the closure of the communication and the installation of the bone graft material [49, 50].

3.3.2.5.4 Sandwich technique using collagen membrane and bone substitutes

The usage of a collagen membrane in conjunction with bone substitutes may be favored for the restoration of an oroantral communication/oronasal fistula. The approach involves the placement of cancellous bovine bone graft particles within two layers of a resorbable collagen membrane. In order to mitigate the risk of leaking, the three edges of the collagen membranes are sutured together utilizing resorbable sutures prior to the insertion of the cancellous bone. After the insertion of the particle grafts, the sandwich structure is secured using resorbable sutures and carefully placed within the defect. Primary closure is achieved by repositioning the buccal and palatal flaps. Subsequent examinations have revealed the development of a calcified structure at the base, exhibiting adequate vertical bone dimensions suitable for the placement of dental implants. By employing this integrated methodology, it is possible to attain closure of both soft and hard tissues without resorting to surgical procedures involving donor sites. Furthermore, this particular approach demonstrates encouraging outcomes in the establishment of an optimal bone height for endosseous implants [62].

3.4 Sinus-lifting surgery

Maxillary sinus elevation surgery is an irreplaceable preprosthetic surgical augmentation technique used for the vertical augmentation in cases with decreased vertical height in the posterior maxilla. This procedure has a low complication rate; perioperative and postoperative complications are usually localized and easily solved.

A significant number of difficulties arise due to an inaccurate preoperative diagnosis. It is crucial to consider the identification of underlying sinus pathology and the various anatomical variances when formulating surgical plans for all patients. Most of the complications occur because of the difficulties encountered during the surgery. These occurrences may arise as a result of intricate anatomical structures, such as thin membranes, incomplete or convex lateral walls, or the presence of septa. Additionally, factors such as the selection of treatment alternatives with less predictable outcomes, insufficient preoperative systemic or local anatomical diagnosis, or errors made by the operator might contribute to these situations.

3.4.1 General principles on the prevention of complications

There are two fundamental principles in achieving success with minimal complication rate. There are two key factors that contribute to the success of this treatment. Firstly, it is crucial for the operating surgeon to possess a thorough understanding of the three-dimensional anatomy of the sinus. This knowledge enables the surgeon to make informed decisions at various stages of the procedure, strategically optimizing the outcomes. Secondly, it is imperative to ensure the sinus is in a healthy state prior to commencing the procedure [63].

In order to reduce the occurrence of problems, it is imperative to do a comprehensive assessment of the patient’s medical history, as well as a meticulous clinical and radiographic evaluation, prior to undertaking a sinus augmentation surgery. The medical history should prioritize sinus diseases, including issues such as compromised nasal airflow, secretions at the back of the nose, or headaches. At such instances, it is advisable to undergo a preoperative consultation with an otorhinolaryngologist before proceeding with sinus lift surgery [64].

Smoking significantly increase the risk of complications associated with the procedure. Therefore, it is highly recommended to encourage smoking cessation before undergoing sinus lift surgery. By quitting smoking, patients can minimize the potential risks and optimize their chances of a successful outcome [65].

3.4.1.1 Open sinus lifting

This technique is a predictable procedure with a high success rate, utilized for the augmentation of the posterior maxilla. An intraoral window is prepared on the lateral wall of the sinus with rotary devices or piezoelectrical surgical instruments, the Schneiderian membrane is elevated, and the graft material is applied inside the created cavity. However, intra-surgical and postoperative complications are encountered, and the surgeon should have knowledge regarding the management of these [66].

3.4.1.1.1 Schneiderian membrane perforation

The occurrence of Schneiderian membrane perforation during the dissection and elevation from the sinus bone walls is a frequently seen perioperative complication in open sinus-lifting procedures. Incidence rates of this complication vary between 20% and 25% [67, 68, 69]. Sinus membrane perforations have been found to be correlated with particular morphological irregularities, including reduced alveolar height, a constricted sinus chamber, and the existence of septa. Additionally, the thickness of the Schneiderian membrane and the surgical technique utilized have also been found to be contributing factors.

The sinus membrane possesses the capacity to be perforated in several circumstances during dental interventions. There are several instances in which caution should be exercised during various stages of sinus lift procedures. These instances include the elevation of the flap by inserting an elevator through a thin crest or lateral wall, the preparation of the lateral window (especially when rotary instruments are used), the elevation of the sinus membrane using hand instruments (due to factors such as a narrow sinus, acute bony angles, thin membrane, and adjacent septa formation), and the placement of graft material with excessive pressure against the membrane.

The utilization of cone-beam computed tomography (CBCT) facilitates the examination and acquisition of significant information pertaining to diverse facets of the maxillary sinus. The measurements of the thickness of the crest and lateral walls are conducted, along with the identification of any discontinuities in the bony walls. The width of the sinus is assessed, and the inclination of the anterior sinus wall is evaluated. The thickness of the membrane is determined, and any septa formations are identified. The health of the sinus is assessed, and the patency of the osteomeatal complex is evaluated. This assessment suggests the potential necessity of presurgical intervention aimed at mitigating the occurrence of postoperative sinusitis and infection.

The frequency of membrane perforation is commonly attributed to the thickness of the membrane [70]. The mean thickness of the sinus mucosa in adult individuals is around 1 mm. However, there is significant variation in this measurement across different individuals. Factors such as the presence of sinus pathology and the use of certain medications might impact the thickness of the sinus membrane [71]. The utilization of computed tomography for preoperative assessment enables the determination of mucosal thickness. However, it is important to note that achieving accurate measurements may not be possible in every situation. Moreover, the likelihood of perforation is dependent on both the thickness of the membrane and the general health condition of the patient [72]. The study revealed that 17% of the sinus instrumentation procedures resulted in membrane rupture, namely in Schneiderian membranes that had a thickness of less than 5 mm [73].

There exists a notable and statistically significant correlation between the gingival phenotypic and Schneiderian membrane thickness, suggesting that the measurement of gingival thickness could potentially serve as a predictive indicator for sinus membrane thickness [74].

The occurrence of bony septa is an additional anatomical feature that correlates with the occurrence of membrane perforations [67, 68, 75]. The technical challenge of elevating the membrane near these anatomical structures arises from the presence of sharp septal edges [76]. To circumvent these regions, it is advisable to meticulously examine the sinus morphology and septal trajectory in a cone-beam computed tomography (CBCT) scan. When septa are detected during radiographic evaluation, it is recommended to increase the anteroposterior window size. This enlargement guarantees that the window encompasses both the anterior and posterior sections of the septum. This process enables the raising of the membrane from both aspects of the septum. The challenge of accessing and perceiving information is heightened when utilizing two smaller windows in order to circumvent the presence of septa.

Once within the sinus cavity, optimal accessibility and clear visibility will enhance the process of elevating the membrane. The positioning and dimensions of the lateral window will impact the surgeon’s capacity to raise the membrane. In order to avoid membrane perforation, it is crucial to exercise coordination and maintain visibility, particularly when dealing with the narrow anterior region of the sinus. It is advised that the margins of the lateral window be positioned 3 mm superior to the sinus floor and 3 mm distal to the anterior wall. This technique facilitates a regulated increase in membrane height and ensures that elevating tools consistently maintain contact with the bone surface.

The utilization of rotary hand instrumentation is a frequently employed technique for performing the lateral window osteotomy procedure, owing to its expeditious nature and widespread availability in most clinical settings [77]. Nevertheless, this particular surgical method has been documented to exhibit the most notable occurrence of membrane perforations, reaching rates as high as 32%. With technological advancements in the field of oral and maxillofacial surgery, the use of piezoelectric surgical units in the lateral window approach is getting more popular since it is a safer way for preparation These devices utilize ultrasonic waves to perform bone osteotomy, thereby mitigating the potential risk of membrane tears, as they are incapable of cutting through soft tissues. The literature reports a range of 3.6–8% for the occurrence rate of membrane perforations while using piezoelectric devices [77, 78, 79], and in most cases, this complication occurs during hand instrumentation and membrane elevation [78, 79].

Various methodologies have been suggested for the management of sinus membrane perforations, contingent upon their dimensions and scope. In cases where the perforation is tiny and situated in a region where the membrane exhibits folding, specific intervention is unnecessary as the folding of the membrane will effectively seal the perforation [76, 80]. Nevertheless, as a consequence of the adverse pressure within the sinus cavity, minor holes have a tendency to enlarge. In such instances, the perforations can be effectively sealed with the application of a fibrin adhesive [81] or with a suture if the perforation is accessible [82, 83].

The utilization of resorbable collagen membranes to cover bigger perforations is a well-established and often employed approach [69, 84]. The resorbable membrane is introduced into the sinus cavity, where it is placed over the perforated area and extends to the bone edges of the osteotomy. The membrane can thereafter be affixed and sustained by employing tacks that are fastened to the cortical buccal bone [85]. In the context of sinus augmentation procedures, it is possible to incorporate a cortical bone sheet within the sinus cavity to cover the area where the membrane has been breached. This step is performed before introducing the particulate graft material [86]. The implementation of a membrane as a covering for the lateral window has been found to be correlated with increased rates of implant survival. In the event of non-utilization, there is a possibility that the graft material could become displaced from the sinus cavity. A significant disparity exists in the incidence of implant failure between implants placed following sinus-lifting procedures with bone blocks compared to those using particulate bone grafts [87].

In cases when the perforation is of significant size or when the Schneiderian membrane is fully exposed, it may be necessary to cancel the treatment. In such instances, a reentry procedure can be considered following a healing period of at least 6–8 weeks [70, 84].

3.4.1.1.2 Rhinosinusitis

Postoperative rhinosinusitis is frequently observed as a result of infection in bone grafts and/or implants. Potential causes of this phenomenon include sinus contamination caused by bacterial infiltration from the oral cavity during surgery, occlusion of the ostium due to excessive graft filling, mucosal edema following surgery, reduced air flow due to decreased sinus volume, impaired mucosal activity resulting from mucosal lacerations, implant protrusion into the sinus, or large membrane perforations [75]. The study population exhibited several prominent symptoms, including muco-purulence (89%), facial pain or pressure (78%), nasal congestion (56%), foul smell (45%), cough (18%), purulent discharge surrounding the implants (18%), ocular pruritus (9%), and postnasal drip (9%). Chronic rhinosinusitis frequently presents within a three-month timeframe following sinus therapy, although it may potentially appear up to 1 year following surgical intervention [30, 88].

Despite the relatively low occurrence rate of postoperative chronic rhinosinusitis, ranging from 4.2% to 8.4% according to various studies [37, 58, 61], the treatment of this condition can be complex and may need the extraction of both graft material and implants [62]. The medical approach involves the administration of systemic antibiotics and use of nasal irrigation, nasal steroid sprays, and oral antihistamine medication, until the infection is effectively managed. It is indicated to do sinus irrigation with antibiotic, anti-inflammatory, and antiseptic medication when patients exhibit symptoms of acute maxillary sinusitis, such as purulent oroantral or nasal discharge [69, 88]. If the pathology is chronic following medicinal treatment, it may be necessary to consider additional surgical intervention. The procedure of reentry surgery involves the utilization of either a traditional Caldwell-Luc osteotomy or endoscopy into the nasal or oral cavities to remove the contaminated graft and/or implants.

3.4.1.1.3 Intraoperative hemorrhage

It is usual to observe anastomoses between the infraorbital artery and the posterior superior alveolar artery within the lateral wall of the sinus. These interconnected blood arteries supply the sinus membrane, the buccal tissues located above the periosteum, and the teeth in the maxillary region [89, 90]. Significant variations can be observed throughout individuals in terms of the physical characteristics and measurements of vessels, as well as their arrangement and location inside the maxillary sinus. The potential occurrence of hemorrhage during sinus augmentation surgery is an issue to consider if any of the arteries sustain damage during either the creation of the bony window or the elevation of the Schneiderian membrane. The incidence of bleeding is projected to increase by up to 57% when the diameter of the artery exceeds 0.5 mm [90]. Analyzing the preoperative CBCT scan to detect the presence of these vessels is crucial to prevent bleeding complications. It should also be kept in mind that if a vessel is identified in one sinus, there is a strong likelihood that a corresponding vessel exists on the contralateral side.

In cases when the artery is situated under the buccal soft tissues, it is reasonable to safely detach it from the underlying bone and afterward displace the buccal flap, without incurring any damage to the artery. A vasoconstrictor (1:50,000 epinephrine) can be used to control soft tissue bleeding that may occur during vertical releasing incisions, while electrocautery is more effective in bleedings from the prepared lateral wall. However, it is imperative to take caution when employing electrocautery due to its potential to induce harm to the membrane, particularly when utilized for the purpose of managing vascular hemorrhaging in proximity to the sinus membrane.

In cases when the artery is located within the bone (intraosseously), it is advisable to adjust the dimensions and placement of the osteotomy in order to circumvent potential contact with this vascular structure. This precaution is necessary due to the elevated likelihood of perforation occurring during the osteotomy procedure. In cases when the vessel is connected to the Schneiderian membrane within the sinus, the doctor may choose between two approaches. The first technique involves detaching and reflecting the artery together with the sinus membrane. Alternatively, the clinician may elect to construct an aperture in the buccal window at a distinct location, ensuring a safe distance from the artery. An intrabony vessel can be compressed with the bone, but membrane should be handled carefully; the sinus membrane internal to the vessel should be elevated after extending the window slightly, and then, the vessel should be clamped with a hemostat for a few minutes.

In the event of arterial damage occurs during a surgical procedure, it is imperative to promptly implement hemostatic interventions in order to effectively manage and mitigate the bleeding. Hemorrhage cessation can occur spontaneously or following the application of direct pressure for a duration of several minutes. When the artery is readily reachable, it can be subjected to clamping using a suitable instrument, followed by suturing on its distal end. In certain cases, it may be necessary to proactively execute arterial saturation when a vessel of significant diameter is situated in a potentially compromising position [89].

In scenarios in which the artery sustains damage in close proximity to the lateral window borders, there is a potential for the artery to become unattainable for clamping. Under such conditions, the administration of hemostatic medications, such as aminocaproic acid, to the affected area may be employed until the necessary level of hemostasis is achieved. In order to prevent blood flow into the surgical field, the surgeon may employ a high-volume, narrow-tipped aspirator to divert bleeding while performing window preparation, membrane elevation, and grafting procedures. Typically, hemostasis is achieved by the end of the grafting procedure, and further episodes of bleeding following closure are generally infrequent. The suction should be utilized for sufficient visibility [63].

3.4.1.1.4 Mucous retention cysts

Mucous retention cysts are encountered commonly in the maxillary sinus. These cysts do not present a contraindication for maxillary sinus lift surgery; however, the presence of these cysts becomes problematic when they are elevated during sinus grafting procedures and obstruct the ostium. The utilization of preoperative CT analysis has the potential to provide valuable insights into the probability of encountering undesirable outcomes, as the identification of cysts can be readily achieved. The use of aspiration as a therapeutic strategy for minor mucous retention cysts is considered acceptable. However, it should be noted that more complex and larger cysts require treatment through functional endoscopic sinus surgery (FESS) prior to undergoing sinus elevation surgery. The likelihood of complicated lesions demonstrating a positive response exclusively to antibacterial or anti-inflammatory medications is low. Therefore, it is imperative to refer the patient to an otorhinolaryngologist for the treatment of these issues prior to undertaking sinus augmentation surgery [63].

Distinction between polyps and mucous retention cysts can be made based on their distinct morphological characteristics and anatomical positioning. Retention cysts exhibit a dome-shaped morphology and arise from the floor of the sinus, whereas polyps display an uneven base and originate from the walls of the sinus. The aspiration of a yellow, serous fluid is indicative of the presence of a retention cyst [63].

If the cyst expands significantly, it will obstruct drainage through the ostium, particularly if it occupies two-thirds of the whole sinus. The identification of this condition before surgery presents two potential treatment approaches. The initial approach involves conducting Functional Endoscopic Sinus Surgery (FESS) before performing sinus-lifting surgery to deal with the cyst. Alternatively, the second approach entails aspirating the contents of the cyst during the sinus elevation procedure. In the second method, complete osteotomy of all the lateral window is performed. Then the cyst is treated by aspiring its contents with a 22-gauge needle.

3.4.1.1.5 Overfilling (ostium blockage)

The occurrence of occlusion of the maxillary sinus ostium due to excessive bone grafting during sinus elevation surgery is infrequent, likely because to the ostium’s advantageous anatomical placement [76]. The obstruction of the ostium might hinder the regular physiological functioning of the sinus and elicit further issues, such as the development of chronic rhinosinusitis [91]. A preoperative radiological assessment is necessary to evaluate the position and openness of the ostium. This can be achieved by the use of a cone-beam computed tomography (CBCT) scan, which allows for the identification of any potential positional deviations.

3.4.1.2 Closed sinus lifting

The closed sinus-lifting technique is characterized by its expedited nature and less invasiveness, resulting in a decreased likelihood of complications when compared to the lateral window approach [92]. The achievement of acceptable primary stability of the implant is only demonstrated when there is minimum residual ridge height present. The existing literature does not provide an evidence-based threshold for determining the appropriate residual ridge height for open or closed sinus-lifting procedures. However, it is generally advised to consider a minimum residual bone height of 4–5 mm when performing the osteotome technique, as suggested in various academic publications [75]. Although the closed method offers certain benefits, it is important to note that this technique requires a high level of technical skill. Additionally, the surgeon’s ability to manipulate the sinus is restricted due to the limited access provided by this approach.

3.4.1.2.1 Schneiderian membrane perforation

One of the most commonly encountered complications is the perforation of the sinus membrane when utilizing an osteotome. Membrane perforations can arise in situations where the membrane exhibits thinness, when the sinus floor possesses an oblique configuration, or when the membrane is elevated beyond a threshold of 3 mm [93, 94].

The presence of perforation can be ascertained with the use of a blunted probe or by performing the Valsalva maneuver. It is advisable to consider the placement of a shorter implant in cases where the remaining bone height permits, as this can help prevent the protrusion of the implant apex into the sinus through the perforated Schneiderian membrane [95].

3.4.1.2.2 Benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo (BPPV) is a commonly seen otoneurologic disorder characterized by brief episodes of vertigo and concurrent nausea. The cause of this disorder has been ascribed to the detachment of otoliths from the utricular macula and their subsequent migration into the semicircular canals. According to existing literature, the incidence rate of benign paroxysmal positional vertigo after to closed sinus-lifting surgery has been documented at 5.84% [96].

The potential cause of otolith dislodgement during closed sinus lifting is hypothesized to be the surgical trauma resulting from the use of osteotomes and a surgical hammer for bone condensation. To reduce the frequency of benign paroxysmal positional vertigo, it is recommended to minimize the trauma caused by osteotomes using precise and careful malleting procedures, as well as by periodically adjusting the patient’s head position during the surgical operation [96].

The manifestation of symptoms occurs during a period of 24–48 hours following the surgery, and these symptoms primarily impact the side of the patient that is opposite to the one where the procedure was performed. The Epley repositioning maneuver, alternatively referred to as the canalith repositioning treatment, has been found to result in full recovery within a span of 2 days. This procedure comprises a series of cranial movements that facilitate the repositioning of the otoliths to their initial state [97].

Patients should be warned about the possibility of suffering temporal vertigo after surgery because the symptoms can be uncomfortable and incapacitating, causing severe stress to the patient, even though in many cases, postoperative benign paroxysmal positional vertigo is self-limiting with time and has a spontaneous recovery [98].

3.4.1.2.3 Implant displacement

Displacement of implants can potentially occur either during a sinus lift treatment or during the manipulation of prostheses. It is recommended to extract the misplaced implant, even in cases where there is no evidence of pathology or clinical symptoms. This is due to the risks of infection, sinusitis, and further dislocation of the foreign body to adjacent anatomical structures if the object is not removed [95].

There are three primary surgical techniques that have been documented for the recovery of a displaced dental implant. The techniques encompass the transnasal approach, the transoral route via the canine fossa, and the direct access through the implant preparation site [95].

In order to mitigate this problem, it is recommended that the implant osteotomy be constructed in a cone-shaped design and that tapered implants be utilized. Also, adequate primary stability should be achieved during implant insertion. For this purpose, the bony bed may be underprepared, the last implant drills may not be used, or the last drills may only be used in the coronal portion of the residual crest [92].

3.5 Orthognathic surgery

Le Fort I maxillary osteotomy is a frequently performed corrective surgical procedure for dentofacial deformities involving the maxilla, due to its diversity of movement directions. Maxillary advancement and impaction movements may change the morphology and size of the maxillary sinuses. Following this procedure, there is an accumulation of blood in the sinuses, leading to inflammatory alterations such as thickening of the mucosal lining and swelling characterized by the accumulation of fluid. As the process of blood resorption progresses, the accompanying mucosal thickening gradually diminishes. The persistence of these modifications may be a potential risk factor for the development of infections and other pathological conditions. By comprehending the alterations that occur in the sinus mucosa following surgery and the various factors that influence these changes, it becomes feasible to anticipate and mitigate associated difficulties, thereby enhancing the safety of surgical procedures [99, 100].

3.5.1 Mucosal thickening

The majority of problems following a Le Fort I osteotomy are primarily associated with atypical fractures and hemorrhage. The utilization of piezoelectric surgery in conjunction with preoperative simulations using 3D models has been found to result in a more secure and expeditious process. This approach has demonstrated efficacy in mitigating mucosal thickening and subsequent issues associated with the maxillary sinus [101].

The presence of broad gaps between the distal and proximal segments of the maxilla might vary depending on the extent of maxillary mobility. The process of bone grafting at these specific places facilitates the development of the surrounding area, hence aiding in the reduction of mucosal thickness.

The use of preoperative and postoperative cone-beam computed tomography (CBCT) images, along with the implementation of techniques such as decreasing the operation time and employing bone grafting, plays a significant role in the prevention and decrease of mucosal hypertrophy subsequent to Le Fort I osteotomy.

3.5.2 Maxillary sinusitis

Postoperative complications involving the maxillary sinuses are primarily due to sinus infections, disruption of the sinus drainage system, and the persistence of an oroantral fistula. Symptoms such as sinus discharge or excessive nasal drainage are common in the postoperative period. However, true cases of perioperative infections of the sinus and postoperative chronic sinusitis are rare [102]. The normalization of the hard and soft tissue occurs on postoperative 2–6 months in over 55% of the patients. Approximately 30% of Le Fort osteotomy patients show some latent sinus mucosal edema and lack of normal mucociliary function at 6 months [103].

Although postoperative sinus infections are uncommon, there exist various potential factors that can contribute to infections following maxillary orthognathic surgery. The possibility for infection arises from the occurrence and persistence of significant hematomas within the sinus cavity. The administration of intravenous antibiotics during the perioperative period, together with the subsequent use of oral systemic antibiotics after surgery, might effectively mitigate the risk of infection in blood clots prior to their natural resorption. Additional factors that may contribute to postoperative sinus infection encompass preexisting sinus disease, a smoking history, dental infection resulting from inadvertent dental trauma during surgery, soft tissue ischemia and vascular compromise, as well as the presence of debris and foreign bodies within the osteotomy lines involving the sinuses. Preexisting sinus pathologies should be identified and treated before surgery as described in the previous sections. Sinus infection originating from the utilization of wires, bone plates, or screws is uncommon, and there is no substantial evidence to suggest a notable rise in infection rates following maxillary surgery [102].

The presence of radiographic haziness in the maxillary sinus can serve as an indication of the continued presence of hematoma and effusion as observed by computed tomography (CT). This particular parameter holds potential for both diagnosing and treating this specific condition. The implementation of a maxillary suction drain subsequent to the surgical procedure has been observed to decrease the presence of haziness in the maxillary sinus on computed tomography (CT) scans. The incorporation of a suction drain in the postoperative management of the maxillary sinus has the potential to be advantageous in diminishing the likelihood of chronic hematoma and effusion, thereby augmenting overall effectiveness. The positioning of a J-P suction tube within the maxilla can be considered a customary procedure following a Le Fort I osteotomy of the maxilla [104].

3.5.3 Surgical ciliated cyst

The occurrence of surgical ciliated cysts in the maxilla is infrequent and typically arises as a consequence following surgical procedures involving the maxillary region or maxillary sinus. The etiology of the “surgical ciliated cyst” is believed to stem from the entrapment of residual sinus mucosa within the osteotomy lines following Le Fort I osteotomy [105]. There exists a hypothesis suggesting that, during the course of healing, minute portions of nasal mucosa become trapped between the bony edges of the maxillary osteotomy. Over time, this particular problem leads to the cystic degeneration and subsequent expansion of the entrapped nasal mucosa.

The radiographic findings reveal a well demarcated, single-chambered radiolucent lesion that is connected to the maxillary sinus [106]. The cyst has the potential to exhibit a periphery of sclerosis, and as it expands in size, the surrounding sinus wall may undergo thinning and ultimately experience perforation [107].

A CBCT should be utilized to outline the characteristics of a POMC and to determine the extent of the lesion, which will be very important when planning surgery, as the orthopantomography may not show any image of the lesion.

This complication can be prevented by suturing any nasal mucosa tear in orthognathic osteotomies before fixating the distal and proximal segments and attention should be paid during surgery to avoid entrapment of epithelium at the osteotomy lines.

The treatment of choice for the surgical ciliated cyst is the enucleation of the cyst [108]. Large unilocular cysts with extensive bony perforations may be treated with marsupialization.

Surgical ciliated cysts are rare after orthognathic surgery. Nevertheless, it is imperative for surgeons to enhance their awareness regarding this potential occurrence to prevent any setbacks in diagnosis. Furthermore, it is crucial to consider this condition as part of the differential diagnosis for patients experiencing symptoms who have previously undergone maxillary orthognathic surgery.

4. Conclusion

The maxillary sinus is a vital structure in the oral and maxillofacial region, playing a significant role in overall health and functionality. Understanding the detailed anatomy, physiology and radiology of the maxillary sinus is essential for performing successful oral and maxillofacial surgical procedures. As such, surgeons must have a thorough understanding on the prevention and management of the maxillary sinus complications to provide safe and effective care for their patients.