The replacement of dentition defects with implant-supported prosthetic structures is a widely adopted practice considered the “golden standard” of functional rehabilitation for dental patients. However, in clinical practice, dental surgeons often face the problem of bone deficiency and the lack of the necessary volume of bone tissue to install dental implants in the desired prosthetic position. This problem is prevalent in the lateral zones of the upper jaw and is the main limiting factor in the application of modern methods of replacing dentition defects.^[1,2] The proximity of the maxillary sinus limits the possibility of installing an implant of the required length in the optimal prosthetic position. Also, it increases the risk of complications arising during surgery among patients with an edentulous upper jaw. It is well known that in patients with a pneumatic upper jaw structure, the maxillary sinus fills the alveolar process and causes “counter resorption”; when the teeth are missing, the alveolar bone may be lost simultaneously from the oral cavity and the maxillary sinus.^[3,4]

Restoring the required volume and quality of alveolar bone on the maxilla is a challenging clinical task that can be approached in a variety of ways. According to numerous studies, the most common method in the aforementioned clinical situations is lateral sinus floor augmentation (open sinus lift). Tatum proposed this technique in 1974, and Boyne and James (1980), as well as other authors, improved it later. The lateral sinus floor augmentation procedure entails cutting the lateral wall of the maxillary sinus and carefully elevating the sinus’s internal mucoperiosteal membrane. During this procedure, a new space is formed that must be filled with bone-substituting material (graft), sometimes simultaneously with the installation of dental implants.^[5,6]

Experience of using lateral sinus floor augmentation in clinical practice allows us to consider it a procedure characterized by high efficiency and the predictability of its results. Even though lateral sinus floor augmentation is regarded as a reasonably safe and predictable procedure, the literature data indicate the high possibility of developing intra- and postoperative complications associated with this operation. Among the most threatening complications, the authors highlight the development of acute and chronic maxillary sinusitis. It is often associated with infection and complete loss of bone grafts or bone substitute material. The authors determine the frequency of acute maxillary sinusitis at 10–26%. The frequency of graft loss, according to other researchers, is lower (3–10%). Since some infectious complications in the case of timely diagnosis and the use of the correct treatment tactics may be effectively eliminated, their negative consequences are minimized. The chronic inflammatory process in the maxillary sinus was noted in 1.3–5% of cases. However, the number of scientific publications devoted to the study of this complication in lateral sinus floor augmentation is limited, and their results are often contradictory.^[7-9]

Some researchers argue that the maxillary sinuses are often a sterile anatomical region. According to some authors, a healthy maxillary sinus is not sterile. The maxillary sinuses of clinically healthy adult patients are slightly polluted with transitory bacteria as the presence of small numbers of inflammatory cells within the maxillary sinus mucosa is a typical state of the airway defense system. Under normal conditions, saprophytic and opportunistic bacteria predominate in the nasal cavity, with microbial interactions occurring in 69.9% of instances. As a result, the nasal cavity microbiota should be deemed “transient” and have no etiological importance. In normal homeostasis, the maxillary sinuses have a varied bacterial colonization (several bacteria, both in the forms of biofilm and planktonic forms)^[8,10]

Performing any surgical interventions in the oral cavity is accompanied by the risk of contamination of the surgical wound with pathogenic microorganisms. That microorganisms may be identified even in healthy patients in clinically significant concentrations. And the lateral sinus floor augmentation procedure (which is also performed intraorally) is not an exception. That is why this is a rational basis for prescribing prophylactic antibacterial therapy. In modern clinical practice, the problem of identifying pathogens in disease is a component of the ongoing process of updating medical and diagnostic protocols and standards. Especially for the treatment of infectious and inflammatory diseases of the maxillofacial region. In those cases, various methods of identifying pathogenic microorganisms may be used.^[11,12] Usually, when using the cultural identification method in the oral cavity, the pathogen may be identified in 85.50% of patients. In general, associations of microorganisms were determined in 96.00% of cases, and monoculture in 4.00%. At the same time, maximum information may be obtained when using molecular genetic identification methods, especially for anaerobes. Because, in standard cultivation, the families Streptococcus, Staphylococcus, and Prevotella spp. (aerobic and facultative anaerobic bacteria) are mainly isolated.^[13,14]

Antibacterial resistance in microorganisms is a unique problem in modern medicine. Antibacterial resistance can be either natural or acquired. The first type of resistance is defined as the absence of target microorganisms for an antimicrobial drug’s action or its unavailability. Acquired resistance is caused by the effect of antimicrobial drugs on microorganisms, particularly at low concentrations. In recent decades, there has been a greater emphasis on understanding bacterial survival mechanisms. Antibiotic resistance among infectious and inflammatory disease pathogens is widespread, posing a serious threat to most countries’ healthcare systems. And the wide usage of antibiotics in the dental practice may enhance the abovementioned problem. Today, it is known that clinical strains of streptococci are the most frequently identified bacteria with resistance to antibiotics, especially to penicillin and clindamycin.^[15]

The vast majority of clinical recommendations for antibacterial prophylaxis involve the use of semisynthetic penicillins (amoxicillin or clavulanate). However, due to the spread of beta-lactam antibiotic resistance among oral microbiome participants, the true efficacy of this class of agents may be questioned.^[16,17] Recommendations for the initiation of antibiotic therapy before planned surgery, including shortened regimens for cephalosporins (within 1 day), seem more rational. However, the “right” antimicrobial agent for prophylactic therapy is an unresolved issue that must be addressed in almost every clinical case.^[18,19]

To determine the species composition of the microorganisms (pathogenic and opportunistic) of the four biotopes in the maxillofacial region (Schneiderian membrane, pharynx, nasal passage, and oral mucosa) during a planned sinus lift, and detect their sensitivity to antibiotics.

Analysis of the literature on the study of various biotopes of the maxillary sinus and Schneiderian membrane during a planned sinus-lift procedure, in particular, shows rather ambiguous and discordant results. Thus, in the study of Carreño Carreño et al.^[20], the published results showed that the maxillary sinus was non-sterile in only 18.10% of patients. The authors reported that the Streptococcus family was prevailing (45.00%), with dominance of S. viridans (61.1%). Also prevailing were the Staphylococci (25.00%) and S. aureus. In addition, Haemophilus influenzae and Klebsiella oxytoca were isolated. In 33% of cases, the culture of microorganisms could not be identified. The isolated microorganisms were resistant to macrolides and had higher sensitivity to penicillins, cephalosporins, and fluoroquinolones. Ampicillin, amoxicillin/clavulanate, and ciprofloxacin were proposed as the most effective antibiotics.^[20]

Salgado-Peralvo et al.^[21] reported higher efficacy of preoperative antibacterial therapy in cases of the sinus lift and dental implantation. The positive effect of local administration of metronidazole solution during surgery was described. Sinus irrigation and wetting of osteoplastic material with metronidazole was believed to improve the integration of bone substitute material and promote the formation of more complete native bone tissue. Penicillins (including amoxicillin/clavulanate) were most often chosen. Ciprofloxacin was prescribed only in cases of allergic reactions to penicillins. Clindamycin and cefazolin were also recommended for preventive antibacterial therapy.^[21]

There are a few reports that demonstrate that administration of azithromycin also helps to reduce the intensity of inflammatory reactions. This effect, however, may be achieved not only by the substance’s antibacterial effect, but also by its anti-inflammatory side effect: azithromycin reduces production of granulocyte colony-stimulating factor, interleukin-6, and interleukin-8, macrophage inflammatory protein 1, and interferon-induced 10 kDa protein in the early stages of the inflammatory process. Azithromycin also reduces the mobilization of granulocyte precursors, as well as immune and inflammatory cell activity during the healing process. In general, similar effects to immunomodulation were observed in all members of the macrolide group, necessitating further investigation. Therefore, azithromycin and clarithromycin were included in the recommended regimens of prophylactic antibacterial therapy when performing dental implantation and sinus-lift procedures.^[22]

The results of Peleg et al.^[23] indicated that in somatically healthy patients during the sinus-lift surgery, the inner sinus membrane was non-sterile (72%). The authors identified the aerobes in 58% of cases and anaerobes in 56%. In 50% of cases, polymicrobial flora was detected.^[23] On et al.^[24] reported that the frequency of infectious and inflammatory complications after sinus-lift surgery was 21%. Mainly, the processes had a bacterial origin, and rare cases of Aspergillus fungi and methicillin-resistant S. aureus identification were described.^[24]

It is also worth considering the recommendations of one of the founders of the open sinus-lift technique: according to the recommendations of Testori et al., prophylactic antibacterial therapy also included two options – amoxicillin/clavulanate (before and after surgery), and for patients with an existing allergy to penicillins the clarithromycin with metronidazole were recommended. In cases of complications, the first group of patients was recommended to receive amoxicillin/clavulanate with metronidazole, and the second group—to replace antibiotics with levofloxacin.^[25]

A study of the species composition of microorganisms in the maxillary sinus and other biotopes of the maxillofacial area in patients who underwent a planned sinus-lift surgery showed that they differ significantly both in species and in sensitivity to antibacterial agents. In the maxillary sinus, in the absence of clinical signs of inflammation, pathogenic microorganisms were present in clinically significant concentrations, mainly Streptococci, Pseudomonas aeruginosa, and fungi of the Candida genus. The frequency of detection of pathogenic microorganisms, their species composition, and concentrations did not allow us to identify relationships between different biotopes of the maxillofacial area. Considering the differences in the species composition of different biotopes of the maxillary sinus, as well as the impossibility of complete isolation of the surgical field when performing sinus-lift surgery, there is a high risk of sinus contamination with microflora that persists in the oral cavity and nasal passages during surgery and in the early postoperative period. Therefore, when planning a prophylactic course of antibacterial therapy in the postoperative period, it is advisable to also take into account the sensitivity to antibacterial agents in representatives of all biotopes. Ceftriaxone and cefoperazone/sulbactam were the most effective in terms of their effect on isolates isolated in clinically significant concentrations. The cultures were mainly sensitive to cefuroxime – 75% of the isolates. Gatifloxacin appeared to be quite effective, with an equal distribution of susceptibility and intermediate susceptibility cases, with no resistance. These findings point to a narrowing of the antibacterial agents available for prophylactic use during sinus-lift surgery. The identified fungi on the mucoperiosteum of the maxillary sinus were sensitive to fluconazole, ketoconazole, and clotrimazole, moderately sensitive to itraconazole and nystatin.

Study procedures were approved by the Bioethics Committee of the State University Uzhhorod National University (Ukraine) (No. 14/1, 17 November 2023). The study adhered to ethical principles as outlined by the Declaration of Helsinki. All participants provided informed consent after a thorough explanation of the study objectives and procedures. All patients provided prior voluntary consent for the collection of biological material for research during the operation.

Performing the study, the results of which are presented in the form of an article, is not related to violation of the ethics of scientific research and relations regulated by the following regulatory legal acts:

This study was performed on a small group of patients (n=15). And that fact may affect the significance of the obtained results. Also, the selection of patients (only persons who planned to install dental implants on the maxilla) may cause a systemic misunderstanding of the real situation of microbiome composition in different maxillofacial biotopes among patients in dental practice. The methods used for sample transportation, microorganism cultivation, and identification allowed the detection of aerobic and facultative anaerobic microorganisms. The potential application of methods specialized for anaerobes may show other results and may change the final clinical recommendation, which is possible to derive from the obtained results. Also, the application of PCR identification of microorganisms might change the final understanding of the situation. The chosen list of antibiotics is wide enough but also adapted to the local situation and experience of infection control in Ukraine.

This study received ethical approval from the Bioethics Committee of the State University Uzhhorod National University (Ukraine) (approval No. 14/1) on November 17, 2023. The study adhered to ethical principles as outlined by the Declaration of Helsinki.

The authors declared that no clinical trials were used in the present study.

The authors declared that no experiments on humans or human tissues were performed for the present study.

The authors declared that all participants provided informed consent after a thorough explanation of the study objectives and procedures. All patients provided prior voluntary consent for the collection of biological material for research during the operation

The authors declared that no experiments on animals were performed for the present study.

The authors declared that no commercially available immortalized human and animal cell lines were used in the present study.

The authors have declared that no competing interests exist.

No funding was reported.

No use of AI was reported.

All authors have contributed equally.

All data used are referenced or included in the article.