Automatic detection of the third molar and mandibular canal on panoramic radiographs based on deep learning.

PURPOSE: This study aims to develop a deep learning framework for the automatic detection of the position relationship between the mandibular third molar (M3) and the mandibular canal (MC) on panoramic radiographs (PRs), to assist doctors in assessing and planning appropriate surgical interventions. METHODS: Datasets D1 and D2 were obtained by collecting 253 PRs from a hospitals and 197 PRs from online platforms. The RPIFormer model proposed in this study was trained and validated on D1 to create a segmentation model. The CycleGAN model was trained and validated on both D1 and D2 to develop an image enhancement model. Ultimately, the segmentation and enhancement models were integrated with an object detection model to create a fully automated framework for M3 and MC detection in PRs. Experimental evaluation included calculating Dice coefficient, IoU, Recall, and Precision during the process. RESULTS: The RPIFormer model proposed in this study achieved an average Dice coefficient of 92.56 % for segmenting M3 and MC, representing a 3.06 % improvement over the previous best study. The deep learning framework developed in this research enables automatic detection of M3 and MC in PRs without manual cropping, demonstrating superior detection accuracy and generalization capability. CONCLUSION: The framework developed in this study can be applied to PRs captured in different hospitals without the need for model fine-tuning. This feature is significant for aiding doctors in accurately assessing the spatial relationship between M3 and MC, thereby determining the optimal treatment plan to ensure patients' oral health and surgical safety.

Short-chain fatty acid - A critical interfering factor for allergic diseases.

Allergy is a growing global public health problem with a high socio-economic impact. The incidence of allergic diseases is increasing year by year, which has attracted more and more attention. In recent years, a number of epidemiological investigations and gut microbiota studies have shown that gut microbiota dysbiosis is associated with an increased prevalence of various allergic diseases, such as food allergy, asthma, allergic rhinitis, and atopic dermatitis. However, the underlying mechanisms are complex and have not been fully clarified. Metabolites are one of the main ways in which the gut microbiota functions. Short-chain fatty acids (SCFAs) are the main metabolites of intestinal flora fermentation and are beneficial to human health. Studies have shown that SCFAs play an important role in maintaining intestinal homeostasis and regulating immune responses by recognizing receptors and inhibiting histone deacetylases, and are key molecules involved in the occurrence and development of allergic diseases. In addition, research on the regulation of gut microbiota and the application of SCFAs in the treatment of allergic diseases is also emerging. This article reviews the clinical and experimental evidence on the correlation between SCFAs and allergic diseases and the potential mechanisms by which SCFAs regulate allergic diseases. Furthermore, SCFAs as therapeutic targets for allergic diseases are also summarized and prospected.

Stem cell microencapsulation maintains stemness in inflammatory microenvironment.

Maintaining the stemness of the transplanted stem cell spheroids in an inflammatory microenvironment is challenging but important in regenerative medicine. Direct delivery of stem cells to repair periodontal defects may yield suboptimal effects due to the complexity of the periodontal inflammatory environment. Herein, stem cell spheroid is encapsulated by interfacial assembly of metal-phenolic network (MPN) nanofilm to form a stem cell microsphere capsule. Specifically, periodontal ligament stem cells (PDLSCs) spheroid was coated with FeIII/tannic acid coordination network to obtain spheroid@[FeIII-TA] microcapsules. The formed biodegradable MPN biointerface acted as a cytoprotective barrier and exhibited antioxidative, antibacterial and anti-inflammatory activities, effectively remodeling the inflammatory microenvironment and maintaining the stemness of PDLSCs. The stem cell microencapsulation proposed in this study can be applied to multiple stem cells with various functional metal ion/polyphenol coordination, providing a simple yet efficient delivery strategy for stem cell stemness maintenance in an inflammatory environment toward a better therapeutic outcome.

Customized Barrier Membrane (Titanium Alloy, Poly Ether-Ether Ketone and Unsintered Hydroxyapatite/Poly-l-Lactide) for Guided Bone Regeneration.

Sufficient bone volume is indispensable to achieve functional and aesthetic results in the fields of oral oncology, trauma, and implantology. Currently, guided bone regeneration (GBR) is widely used in reconstructing the alveolar ridge and repairing bone defects owing to its low technical sensitivity and considerable osteogenic effect. However, traditional barrier membranes such as collagen membranes or commercial titanium mesh cannot meet clinical requirements, such as lack of space-preserving ability, or may lead to more complications. With the development of digitalization and three-dimensional printing technology, the above problems can be addressed by employing customized barrier membranes to achieve space maintenance, precise predictability of bone graft, and optimization of patient-specific strategies. The article reviews the processes and advantages of three-dimensional computer-assisted surgery with GBR in maxillofacial reconstruction and alveolar bone augmentation; the properties of materials used in fabricating customized bone regeneration sheets; the promising bone regeneration potency of customized barrier membranes in clinical applications; and up-to-date achievements. This review aims to present a reference on the clinical aspects and future applications of customized barrier membranes.

[Role and significance of pelvic four-contrast defecography in the diagnosis of outlet obstructive constipation].

OBJECTIVE: To study the changes in pelvic floor morphology and relationships of the pelvic organs in patients with outlet obstructive constipation (OOC). METHODS: Fifty-nine OOC patients and 12 healthy volunteers were examined by simultaneous pelvic four-contrast defecography, including pelvicography, vaginal opacification, voiding cystography and defecography. The levels of perineum, peritoneum and bladder, and anorectal angle were measured and recorded. RESULTS: Among the 59 OOC patients, 46 cases of internal rectal prolapse (IRP), 29 cases of pelvic floor hernia, 7 cases of rectocele (RC), 7 cases of spastic pelvic floor syndrome (SPFS), 5 cases of descending perineum syndrome were diagnosed by pelvic four-contrast defecography. Six cystoceles and 10 uterine prolapses were also found by pelvic four-contrast defecography. Compared with healthy volunteers, OOC patients had significantly large anorectal angles during defecation (P<0.05), abnormality descending of perineum during rest and defecation (P<0.05, P<0.01), and a deep pouch of Douglas during defecation (P<0.01). OOC patients combined with urinary system symptoms had an abnormal descent of the bladder during rest and defecation (P<0.05, P<0.01). CONCLUSION: Pelvic four-contrast defecography is an effective method for the diagnosis of IRP, RC, pelvic floor hernia, peritoneocele, cystocele and uterine prolapse, and is helpful in the selection of proper surgical procedures for the treatment of OOC.

Expression of c-kit messenger ribonucleic acid and c-kit protein in sigmoid colon of patients with slow transit constipation.

BACKGROUND AND AIMS: The c-kit protooncogene receptor and its ligand stem cell factor regulate the proliferation and survival of germ cells as well as interstitial cells of Cajal (ICCs). Decreased numbers of ICCs and defects in its networks have been reported in the colon of patients with slow transit constipation (STC). However, little information about the c-kit messenger ribonucleic acid (mRNA) and protein expression in the constipated colon is available. The aim of this study was to determine whether the expression of c-kit mRNA and c-kit protein declined in the colon in STC. PATIENTS AND METHODS: The sigmoid colonic samples from 12 patients with STC and from eight age-matched patients with non-obstructed colorectal cancer were used for this study. Expression of c-kit mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), and expression of c-kit protein was detected by Western blot analysis. RESULTS: Decreased expression of c-kit mRNA was demonstrated in the STC group compared with the control group. The ratio of c-kit and beta-actin was 1.26+/-0.32 in controls and 1.17+/-0.41 in the STC group (U=0.500, P=0.029). c-kit protein expression significantly declined in the STC group. The mean value of optical density was 162.97+/-5.43 in the control group and 96.64+/-8.80 in the STC group (U=0.000, P=0.021). CONCLUSIONS: The data indicate that the expression of c-kit mRNA and c-kit protein significantly decreased in the colon of STC, suggesting that the c-kit signal pathway may play an important role in ICC reduction in STC.

Role of pelvicography and colpocystodefecography in diagnosis of outlet obstructive constipation.

AIMS: The aim was to research the changes in pelvic floor morphology and corresponding visceras in patients with outlet obstructive constipation (OOC). PATIENTS AND METHODS: Thirty-eight patients with OOC and 12 healthy volunteers were enrolled in this study. With simultaneous pelvicography and colpocystodefecography (PCCD), including pelvicography, vaginal opacification, voiding cystography and defecography, pelvic floor morphology was observed and the anorectal angle, the level of the perineum, peritoneum and bladder were measured. RESULTS: Thirty-seven cases of internal rectal prolapse (IRP), 5 cases of rectocele (RC) and 5 cases of spastic pelvic floor syndrome SPFS were diagnosed by PCCD. 12 IRP, 4 RC and 1 SPFS were detected by common physical examination. All of these were confirmed by PCCD. Moreover, PCCD found 9 pelvic floor hernia or peritoneoceles, 6 cystoceles, 3 descending perineum syndromes and 10 uterine prolapses. Compared with controls, OOC patients had a significantly large anorectal angle during defecation, abnormal descending of the perineum at rest and during defecation, and a deep pouch of Douglas during defecation. Some patients with urinary system symptoms may have had an abnormal descent of the bladder during rest and defecation. CONCLUSION: Simultaneous PCCD has a higher positive ratio than the common physical examination in diagnosing IRP and RC, and provides information for the diagnosis of pelvic floor hernia or peritoneocele, cystocele or uterine prolapse. PCCD is helpful in the selection of a proper surgical procedure.

[Study on distribution of interstitial cells of Cajal in the sigmoid colon of patients with slow transit constipation].

OBJECTIVE: Slow transit constipation (STC) is a colonic motor disorder whose etiology remains unclear. Recent studies have demonstrated a crucial role for interstitial cells of Cajal (ICC) in regulation of intestinal motility. The aim of this study was to examine the distribution of ICC within the normal sigmoid colon and STC patients. METHODS: Twelve patients with STC and eight age-matched controls were studied. ICC were identified with a monoclonal antibody to c-kit by an indirect immunofluorescence method. Immunostained tissues were examined with a laser scanning confocal microscope and the area occupied by ICC was calculated with image analysis software. RESULTS: ICC were located in the external muscle layers including longitudinal muscle (LM), myenteric plexus (MP), circular muscle (CM) and submucosal border (SMB). Two types of Kit-positive ICC were observed: bipolar cells characterized by one or two long processes, and multipolar cells with long stellate processes extending in various directions. A higher percentage of ICC was present in the MP regions and CM layers compared with the SMB and LM layers. Tissues from STC patients showed considerably decreased in number of ICC located in the four regions (ICC-LM, ICC-MP, ICC-CM, ICC-SMP), especially for ICC-SMP, almost completely disappeared. CONCLUSION: Decreased c-kit + ICC in number may play an important role in the pathophysiology of STC. It remains to be determined whether loss of ICC is primary or secondary to another lesion.

Effects of mu and kappa opioid receptor agonists and antagonists on contraction of isolated colon strips of rats with cathartic colon.

AIM: To study the effects of mu and kappa opioid receptor agonists and antagonists on the isolated colon strips of rats with cathartic colon. METHODS: Cathartic colon model was established by feeding rats with contact laxatives, and effects of mu and kappa opioid receptor agonists and antagonists on electricity-stimulated contraction of isolated colon strips of rats with cathartic colon were observed. RESULTS: Compared with control group, exogenous mu and kappa agonists inhibited significantly electricity-stimulated contraction of strips of cathartic colon (8.50+/-0.89 mm, 6.24+/-0.91 mm, 3.35+/-0.6 mm vs 11.40+/-0.21 mm P<0.01; 8.98+/-0.69 mm, 6.89+/-0.71 mm, 4.43+/-0.99 mm vs 11.40+/-0.21 mm, P<0.01). In contrast, the exogenous mu antagonist significantly enhanced electricity-stimulated contraction of isolated colon strips (13.18+/-0.93 mm, 15.87+/-0.98 mm, 19.46+/-1.79 mm vs 11.40+/-0.21 mm, P<0.01), but kappa antagonist had no effect on the isolated colon strips of rats with cathartic colon. CONCLUSION: Mu and kappa opioid receptors are involved in the regulation of colon motility of rats with cathartic colon.

Decreased interstitial cells of Cajal in the sigmoid colon of patients with slow transit constipation.

BACKGROUND AND AIMS: Slow transit constipation (STC) is a colonic motor disorder that is characterized by measurably delayed movement of materials through the colon. Although abnormalities in the neuronal networks of the colon have been demonstrated in patients with STC, the etiology of STC remains unclear. Interstitial cells of Cajal (ICC) have been shown to be the pacemaker cells of the intestine and have been implied in the pathogenesis of a number of gastrointestinal motility dysfunctions, including idiopathic STC. This study aimed to determine the normal distribution of ICC within the colon of the Chinese and also to determine if ICC are decreased in Chinese STC patients. PATIENTS AND METHODS: Twelve patients with STC and eight age-matched normal controls were studied. Specimens of sigmoid colon were obtained immediately after resection. ICC were identified with a monoclonal antibody to c-kit by an indirect immunofluorescence method. Immunostained tissues were examined with a laser scanning confocal microscope and the area occupied by ICC was calculated with an image analysis system. RESULTS: ICC were located in the external muscle layers including myenteric plexus (MP) and submucosal border (SMB). Two types of Kit-positive ICC were observed: bipolar cells characterized by one or two long processes and multipolar cells characterized by long stellate processes extending in various directions. A higher percentage of ICC was present in the MP regions and circular muscle (CM) layers compared with the SMB and longitudinal muscle (LM) layers. Tissues from STC patients showed a considerable decrease in the number of ICC located in the four regions (ICC-LM, ICC-MP, ICC-CM, ICC-SMB), especially the ICC-SMB, in which ICC almost completely disappeared. CONCLUSIONS: Similar distribution of ICC was observed in the normal sigmoid colon of the Chinese. Decreased area of c-kit+ ICC may play an important role in the pathophysiology of STC. It remains to be determined whether the loss of ICC is primary or secondary to another lesion.

Transvaginal local excision of rectal carcinoma.

PURPOSE: To recommend a new approach-transvaginal local excision of early rectal cancers-and report the results of the approach applied by dedicated surgeons at a specialized colorectal unit during a 10-year period. METHODS: The surgical outcome of 18 patients undergoing transvaginal local resection between January 1991 and August 2001 was reviewed. Patients were identified according to the consultants' personal records and cross-referenced with the operating room logs. Data were collected retrospectively, and follow-up was performed on all patients. RESULTS: A total of 18 patients underwent 18 procedures during the study period. Follow-up ranged from 2 months to 104 months. There were no treatment-related complications. Two patients suffered from recurrences at a median follow-up time of 35.7 months, but they underwent subsequent surgical treatment: APR (one) and LAR (one). No evidence of disease was found during a median follow-up of 20 months (12 and 28 months). No one died. CONCLUSIONS: Transvaginal local excision is an alternative and feasible technique with low rates of death and complications for the treatment of rectal cancer in strictly selected cases.