Saliva is rich in DNA, RNA, proteins, microorganisms and metabolites, containing large amounts of bio-information, similar to blood, and reflecting the physiological or pathological state of the whole body. Additionally, with its advantages of non-invasive collection methods, safe transport and low transportation cost, saliva has attracted extensive attention of scholars recently as a potential substitute for blood. With the rapid development of high-throughput techniques such as microarray technology, whole genome sequencing and whole transcriptome sequencing, a variety of disease-specific salivary biomarkers have been discovered. Salivary transcriptomics, a bridge connecting genomics and proteomics, provides a comprehensive understanding of gene transcription, RNA composition and interactions. This methodology not only allows the investigation of salivary components with temporal and spatial specificity but also reveals regulatory networks during disease development, with high potential for the early screening and assessment of diseases. Here, we outline the development of salivary transcriptomics, highlight its current research status in oral cancer from two aspects of technological and clinical applications, and further address prospects and challenges of the near future.

The 4th edition of WHO Classification of Head and Neck Tumours has been published in Jan. 2017. In Chapter 8 ‘Odontogenic and maxillofacial bone tumours’, the classification of odontogenic tumors was recomposed from the previous edition in 2005. In this paper, we introduced the modification of odontogenic tumors classification between 2017 and 2005 in a comprehensive discussion.

Decompression is an effective and widely used treatment for jawbone cystic lesions that can, to a great extent, preserve the function and appearance of the jawbone. However, some problems exist with its clinical application, such as the inappropriate determination of indication and the lack of standardized operational guidelines, resulting in treatment ineffectiveness or even failure. This paper aimed to summarize the clinical value of decompression for jawbone cystic lesions in terms of mechanism, scientific evidence, advancement, indications and effective evaluation by reviewing relevant literature and our clinical experience.

Parotid obstructions can cause repeated swelling of the glands. Previously, duct stones were thought to be the main cause of obstructions, but salivary gland endoscopy examinations have revealed the absence of stones or foreign bodies in the duct system of the parotid glands with obstructive symptoms. Diseases of the parotid gland with obstructive symptoms include chronic recurrent parotitis, non-stone chronic obstructive parotitis, Sjögren′s syndrome, IgG4-related parotitis and radiation-induced parotitis. The mechanism of obstructions is unknown, and the disease course is prolonged. In this paper, based on a brief analysis of duct stenosis, distortion and mucus emboli, which may lead to parotid obstructions, a new perspective is emphasized: the duct system of the parotid and flowing saliva constitute a microflow field. Based on the principle of fluid mechanics, the flow of saliva in the flow field can be affected by the confluence, diameter changes, and twist of the ducts. This outcome results in changes in the low velocity zone, backflow, counterflow and turbulence; affects saliva flow and normal discharge; and causes symptoms of parotid obstruction. An analysis of the possible mechanisms of parotid obstruction using two variables, duct anatomy and saliva traits, helps explain the causes of nonstone parotid obstructions.

Marsupialization is effective in the treatment of cystic lesions of the jaw. It is a simple operation that can result in minimal trauma, the reduction of postoperative recurrence, and maximum preservation of the surrounding tissue structure and function. However, there is a certain failure rate in clinical treatment due to the improper grasp of indications and nonstandard operation. The highest failure rate reported in the literature is 32.6%. To further standardize the clinical application of marsupialization and improve the success rate of treatment, we put forward an expert consensus of marsupialization in the treatment of jaw cystic lesions by reviewing the domestic and foreign literature and summarizing the experience in marsupialization from some famous domestic experts. In this consensus, we propose three elements of marsupialization: the establishment of the opening, the maintenance of cyst plugs and regular washing. The scope of application of marsupialization includes jaw cysts and cystic ameloblastomas. It is necessary to standardize the position of the opening, the size of the opening and the manufacture of the cyst plug, and a panoramic film or cone beam computed tomography(CBCT) should be used to observe the changes in the cystic cavity before and after operation. A second-stage operation should be performed when the lesion is significantly reduced by more than 50% or at least 5 mm from important structures; furthermore, the teeth of focus should be treated according to the relationship between the lesion and tooth and the type of tooth.

A substantial revision of the classification of ameloblastoma was made by the World Health Organization (WHO) in the fourth edition of the Classification of Head and Neck Tumors in 2017, which was based on the review and summary of much clinical research data and prospective evaluation of the latest results of genetic research. The new classification is simpler and more practical. It retains two subtypes, the unicystic type and extraosseous/peripheral type, classifies the remaining types as ameloblastoma (classic), defines metastatic ameloblastoma as a benign tumor and simplifies the classification of ameloblastic carcinoma, which has important guiding significance for clinical diagnosis and treatment. Moreover, the new classification included the latest advances in the genetic research on ameloblastoma, demonstrating that the BRAF gene mutation was found in approximately 60% of ameloblastoma cases. The classification provides a new concept and direction for studying the pathogenesis of ameloblastoma, and BRAF-targeted therapy may be an emerging therapy for some ameloblastoma patients with multiple recurrence or surgical contraindications. This article analyzes the intrinsic logic of these changes via a review of the relevant literature and combination of clinical experiences to better understand the new classification. In 2017, the WHO′s new classification of ameloblastoma summarized the experience and achievements in histopathology and clinical treatment of ameloblastoma in the prior 10 years, indicating that BRAF-targeted treatment may bring new treatment options and hope for patients with recurrent or inoperable ameloblastoma.

Most salivary gland stones involve the submandibular gland, which often cause recurrent swelling and pain of the glands after meals, and used to be the main reasons for the gland removals. With the trend of minimally invasive treatment, gland preservation and functional recovery in the diagnosis and the treatment of submandibular lithiasis have been paid more and more attention. New equipment and technologies such as CBCT and sialendoscopy, which are widely used in clinical practice, have contributed a lot to the accurate orientation and minimally invasive treatment of stones, and enriched the managements of submandibular lithiasis. Based on our experience and the review of relevant literature, this paper attempts to summarize the treatment strategies for submandibular stones distributed in different parts of the duct: ① emphasizing on the integrity and functions of the organ; ② endoscopy and minimal invasiveness come first; ③ scientific classifications and personal managements. Appropriate treatment options should be selected according to the features of the stones: endoscopic lithotomy helps a lot in removing those located in the anterior or middle part of the duct; endoscopic lithotomy or/and sialolithotomy are needed according to the features of hilar stones; the regular follow-up is required for the intraglandular stones. Meanwhile, the evaluation of the gland function is also important. After the removals of sunmandibular stones, the functions of the glands should be promoted to restore as far as possible.

Chronic obstructive diseases of the parotid gland are common clinically, with repeated swelling and a prolonged course and poor treatment outcomes. Based on the summarization of clinical practice and related literature, from the viewpoint of etiology, parotid obstructive diseases can be classified as mechanical obstructions, specific obstructions and non-specific obstructions. The principles of fluid mechanics are introduced to explain the formation of parotid obstructions. According to the different causes, the methods of changing the flow pattern of saliva in the parotid to reduce the resistance and relieve the obstruction, are proposed, such as mechanical factors removals, application of drugs that promote saliva secretion and lower saliva viscosity, ductal expansion under endoscopy and stent placement, and embolization of collateral ducts. These managements can effectively increase the salivary flow rate, reduce the occurrence of the saliva stranded and parotid gland obstructions.

TNM (tumor node metastasis) classification is a common way to evaluate the prognosis of patients with oral cancer; however, many years of application have proven this method to be confined merely in clinical and pathological data and it cannot be adapted to the development of modern medicine. Deep learning (DL) has been widely used in various aspects of human life, has advantages for conducting efficient and intelligent searches and can explore and analyze substantial medical information well. Additionally, the application of DL to medical practice is quickly increasing. In the field of oral cancer prognosis, DL can efficiently process and analyze the pathological, radiographic and molecular data of oral cancer patients represented by lymphocytes, gray level cooccurrence matrix (GLCM) and gene maps and make accurate prognostic judgments accordingly. By assisting physicians in optimizing treatment plans, DL can effectively improve patients' survival. Although DL lacks sufficient data and practical clinical application in prognostic studies, it has shown good clinical application prospects.

Sjögren′s syndrome lacks a single and objective diagnostic index, and its diagnosis often requires comprehensive analysis according to classification criteria. With increasing research and a deepening understanding of the disease, the classification criteria are constantly being adjusted and revised. The sensitivity and specificity of the diagnosis have gradually improved, which has the value of diagnostic criteria largely. Since 1965, more than ten diagnostic criterias for Sjögren′s syndrome have been published. After debate and experience, international criteria with wide applicability have gradually replaced regional criteria. In the evolution of the diagnostic criteria, the diagnostic rules and evaluation methods have become more concise and unified. Techniques with poor specificity and operative difficulty, which are not easy to popularize or apply in the clinic, have gradually been eliminated. A diagnostic system based on an objective examination and subjective symptoms has gradually formed, and lip gland biopsy and serum autoantibody sampling have demonstrated great diagnostic value. The optimization of diagnostic rules makes the diagnosis of this disease more efficient and scientific. This paper reviews the characteristics of and differences in diagnostic criteria for Sjögren′s syndrome and analyzes the internal logic of the evolution of different diagnostic criteria in light of development in research on the disease with the hope of benefitting the diagnosis, treatment and related research of Sjögren′s syndrome.