[Efficacy and safety analysis of bupivacaine liposome for pericapsular nerve group block for postoperative analgesia in elderly patients with hip replacement].

Objective: To investigate the efficacy and safety of bupivacaine liposome for pericapsular nerve group block (PENGB) for postoperative analgesia in elderly patients with total hip replacement. Methods: A total of 42 elderly patients underwent total hip replacement were selected in the Second Affiliated Hospital of Wenzhou Medical University from May to July in 2023, including 19 males and 23 females, aged (68.8±6.3) years, the American Society of Anesthesiologists (ASA) grade Ⅰ to Ⅲ. They were divided into bupivacaine liposome group (observation group) and levobupivacaine hydrochloride group (control group) according to random number table, with 21 cases in each group. All the patients were anesthetized by lumbar anesthesia combined with PENGB. During PENGB, the observation group was injected with 10 ml (133 mg) bupivacaine liposome+5 ml normal saline, and the control group was injected with 10 ml (75 mg) levobupivacaine hydrochloride+5 ml normal saline. The primary outcome measures included the rest and movement visual analogue scale (VAS) scores at 6, 12, 24, 36, 48, 60, and 72 h after operation, the sufentanil consumption in analgesic pump, the numbers of analgesic pump compressions, and the rates of additional parexib sodium use in ward. The secondary outcome measures were the changes in lower limb muscle strength, the length of hospital stay and the occurrence of adverse reactions. Results: There was no significant difference in the rest and movement VAS scores between the two groups at pre-operation and at 6 h after operation (P>0.05);but the rest and movement VAS scores at 12, 24, 36, 48, 60 and 72 h after operation in observation group were significantly lower than those in control group (P<0.05); the rest and movement VAS scores at 6, 12, 24, 36, 48, 60 and 72 h after operation were lower than those at pre-operation in two group (P<0.05). The consumption of sufentanil in analgesic pump and parexib sodium usage in observation group were lower than those in control group at 12, 24, 36 and 48 h after operation (P<0.05). The total number of analgesic pump compressions, the number of effective compressions and the number of ineffective compressions in 48 h in observation group were lower than those in control group (P<0.05). The muscle strength of the lower limbs of all patients were able to move against gravity at 12 h after operation. The incidence of nausea in 48 h after operation in observation group was 9.5% (2/21), which was lower than 42.9% (9/21) in control group (P=0.014). No postoperative vomiting occurred in all patients. The length of the hospital stay was (9.3±2.2) d in observation group and (8.9±1.9) d in control group, and there was no significant difference between the two groups (P=0.500). Conclusion: Compared with levobupivacaine hydrochloride, liposomal bupivacaine in PENGB provides analgesic effects for up to 72 h after total hip replacement in elderly patients, reduces postoperative opioid and other analgesics usage, decreases the incidence of postoperative nausea, and has a minor effect on lower limb movement without prolonging hospitalization.

[Effects of three self-etch adhesives and mild salivary contamination on the bonding durability of deciduous teeth].

OBJECTIVE: To compare the bonding durability of three different self-etch adhesives to primary enamel and dentin, and to investigate the effect of mild salivary contamination followed by air drying on the bonding durability. METHODS: Two hundred and forty enamel specimens were divided randomly into 16 groups (n=15/group)according to the adhesive system [self-etch adhesives: Clearfil SE Bond(SE), AdperTM Easy One (EO), Scotchbond Universal (SBU); total-etch adhesive: AdperTM Single Bond Plus(SL)], contamination status (non-contaminated vs. salivary-contaminated) and storage condition (stored in distilled water for 24 h vs. aging mode 5 000 thermal cycles in 5 ℃ and 55 ℃). Two hundred and forty dentin specimens were assigned in the same way. Shear bond strength for 12 specimens in each group were measured. The adhesive interface for the residual specimens in each group was observed by scanning electron microscopy(SEM). Data were analyzed by three-way analysis of variance and Tukey test(P < 0.05). RESULTS: For primary enamel, total-etch adhesive showed higher initial shear bond strength values (28.92±1.83) MPa and shear bond strength values (27.27±3.03) MPa after thermal cycles compared with the other groups, and the difference between the groups was statistically significant (P < 0.01). Shear bond strength values of EO decreased significantly in salivary-treated groups, regardless of storage conditions, and the difference was statistically significant (P < 0.01). For primary dentin, shear bond strength values of EO decreased significantly in salivary-treated groups after 24 h (P < 0.01). After 5 000 thermal cycles, total-etch adhesive showed significantly lower shear bond strength values (14.31±1.97) MPa compared with the other groups, and the difference between the groups was statistically significant (P < 0.01), and shear bond strength values of EO were significantly lower than those in SE and SBU groups (P < 0.01), regardless of contamination status. CONCLUSION: Total-etch adhesive SL has better bonding durability to primary enamel. SE and SBU have better bonding durability to primary dentin and have a certain resistance to salivary contamination, while the bonding performance of EO is compromised greatly by mild salivary contamination followed by air drying.

[Comparative study of differentiation potential of mesenchymal stem cells derived from orofacial system into vascular endothelial cells].

OBJECTIVE: To compare the proliferation and capacity of differentiation to vascular endothelial cells and angiogenesis induction among stem cells from human exfoliated deciduous teeth (SHED), dental pulp stem cells (DPSC) and human bone marrow mesenchymal stem cells (BMSC) from orofacial bone. METHODS: SHED and DPSC were isolated from pulp tissue of the patients. BMSC were isolated from orthognathic or alveolar surgical sites. The surface markers of the cells were detected by flowcytometry. Cell counting kit-8 (CCK-8) assays were conducted to detect the proliferation ability of the cells. The cells were induced into endothelial cells with conditional medium and then the induced cells were cultured in Matrigel medium. The expression of angiogenesis-related genes such as platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 1 (VEGFR1), vascular endothelial growth factor receptor 2 (VEGFR2) and von Willebrand Factor (vWF) were quantified by real-time PCR. The cells were cultured in chick embryo chorioallantoic membrane (CAM) and the vessels were counted after 5 days. RESULTS: The cell surface markers CD73, CD90, CD105 and CD146 of all the stem cells were positive, CD34 and CD45 were negative. The CD146 positive rate of SHED and DPSC was higher than that of BMSC. SHED had a higher proliferation rate than DPSC and BMSC. After angiogenic induction for 14 d, 3 kinds of cells emanated pseudopodia formed grid structure long vasculature in Matrigel media. The total length of tube formation of induced BMSC (7 759.7 µm) and SHED (7 734.3 µm) was higher than DPSC (5 541.0 µm). The meshes number of induced SHED (70.7) was higher than DPSC (60) and BMSC (53.7) in Matrigel medium. The expression of CD31, VEGFR2 and vWF genes of SHED were higher than those of BMSC and DPSC. VEGFR1 gene expression of BMSC was higher than that of the other groups, and SHED was higher than DPSC. The expression of VEGF showed no difference among the cells. No deference was showed between the effect of the stem cells and negative control on new formed vessels in CAM. The total length of vessels of SHED (30.4 mm) was higher than that of the negative control (20.9 mm) and BMSC (28.0 mm). CONCLUSION: SHED, DPSC and BMSC can differentiate into vascular endothelial cells. SHED showed a stronger angiogenesis differentiation and proliferation potential compared with DPSC and BMSC.

Effect of propolis on preserving human periodontal ligament cells and regulating pro-inflammatory cytokines.

BACKGROUND/AIM: Propolis has been suggested as a storage medium for avulsed teeth. The aim of this study was to compare the effectiveness of Brazilian propolis with Hank's balanced salt solution and milk in maintaining the viability of human periodontal ligament cells, their osteogenic differentiation potential, and pro-inflammatory cytokine expression. MATERIAL AND METHODS: Cell Counting Kit 8 assays were performed to test human periodontal ligament cell viability in different storage media. The preservative effect on osteogenic differentiation was evaluated using alkaline phosphatase staining and activity assays, Alizarin Red S staining, and western blotting. Quantification of pro-inflammatory cytokines was performed using real-time PCR and enzyme-linked immunosorbent assays. RESULTS: Brazilian propolis at 10 µg/ml was not cytotoxic toward human periodontal ligament cells. The milk group showed the highest cell viability. Brazilian propolis and Hank's balanced salt solution groups showed similar cell viabilities. Alkaline phosphatase staining and activity were similar in all groups. Calcium deposition and mineralization nodule formation were similar in the Brazilian propolis and Hank's balanced salt solution groups, but were higher in the milk group. Osteogenic marker gene and protein levels were similar in all groups. The genes and protein expression levels of IL1ß, IL6, and IL8 decreased significantly after treatment with Brazilian propolis. TNFα mRNA expression showed no significant difference among the experimental groups. Pro-inflammatory cytokine levels in the milk group were higher than in the Brazilian propolis and Hank's balanced salt solution groups. CONCLUSIONS: Brazilian propolis, Hank's balanced salt solution, and milk maintained the viability of human periodontal ligament cells and preserved their osteogenic differentiation ability similarly. However, Brazilian propolis showed a better anti-inflammatory effect. This article is protected by copyright. All rights reserved.

Biological and bactericidal properties of Ag-doped bioactive glass in a natural extracellular matrix hydrogel with potential application in dentistry.

The aim of this study was the fabrication and evaluation of a novel bioactive and bactericidal material, which could have applications in dentistry by supporting tissue regeneration and killing oral bacteria. Our hypothesis was that a new scaffold for pulp-dentin tissue engineering with enhanced antibacterial activity could be obtained by associating extracellular matrix derived from porcine bladder with an antibacterial bioactive glass. Our study combines in vitro approaches and ectopic implantation in scid mice. The novel material was fabricated by incorporating a sol-gel derived silver (Ag)-doped bioactive glass (BG) in a natural extracellular matrix (ECM) hydrogel in ratio 1:1 in weight % (Ag-BG/ECM). The biological properties of the Ag-BG/ECM were evaluated in culture with dental pulp stem cells (DPSCs). In particular, cell proliferation, cell apoptosis, stem cells markers profile, and cell differentiation potential were studied. Furthermore, the antibacterial activity against Streptococcus mutans and Lactobacillus casei was measured. Moreover, the capability of the material to enhance pulp/dentin regeneration in vivo was also evaluated. Our data show that Ag-BG/ECM significantly enhances DPSCs' proliferation, it does not affect cell morphology and stem cells markers profile, protects cells from apoptosis, and enhances in vitro cell differentiation and mineralisation potential as well as in vivo dentin formation. Furthermore, Ag-BG/ECM strongly inhibits S. mutans and L. casei growth suggesting that the new material has also anti-bacterial properties. This study provides foundation for future clinical applications in dentistry. It could potentially advance the currently available options of dental regenerative materials.

The association between the RAGE G82S polymorphism, sRAGE and chronic periodontitis in Taiwanese individuals with and without diabetes.

BACKGROUND AND OBJECTIVE: The present study investigated the association between the RAGE G82S polymorphism, the plasma levels of sRAGE and chronic periodontitis in subjects with and without diabetes mellitus (DM). MATERIAL AND METHODS: A total of 230 patients with DM and 264 non-DM participants were recruited for this study. Genotyping of the RAGE G82S polymorphism was accomplished using polymerase chain reaction-restriction fragment length polymorphism, and associations were analyzed with the chi-squared test and logistic regression analysis. RESULTS: In the non-DM group, the chi-squared test showed that the frequency distributions of the G82S polymorphism were significantly different between chronic periodontitis and non-chronic periodontitis subjects (χ(2) = 8.39, p = 0.02). A multivariate logistic regression model showed that the (G82S + S82S) genotypes were associated with a significantly increased risk of chronic periodontitis development compared to the G82G genotype (adjusted odds ratio = 2.06, 95% confidence interval: 1.08-4.07). In the DM group, there was no association between the G82S polymorphism and chronic periodontitis development when a multivariate logistic regression was performed. Plasma levels of sRAGE were significantly higher in subjects with the G82G genotype compared to those with the (G82S + S82S) genotypes in both the non-DM (856.6 ± 332.0 vs. 720.4 ± 311.4 pg/mL, p = 0.003) and DM groups (915.3 ± 497.1 vs. 603.5 ± 298.3 pg/mL, p < 0.0001). However, there was no difference in plasma sRAGE levels between chronic periodontitis and non-chronic periodontitis subjects in both the DM and non-DM groups. Moreover, when the subjects were further sub-divided by the G82S polymorphism, the difference in plasma levels of sRAGE between chronic periodontitis and non-chronic periodontitis subjects in the DM and non-DM groups remained statistically insignificant. CONCLUSIONS: The present study revealed that the RAGE G82S polymorphism was associated with chronic periodontitis in the non-DM group but not in the DM group. Our results also showed that the plasma levels of sRAGE were significantly higher in subjects with the RAGE G82G genotype, and this correlation was not affected by the presence of chronic periodontitis in the DM and non-DM groups.

Development and validation of single nucleotide polymorphism markers in Odontobutis potamophila from transcriptomic sequencing.

Transcriptome sequencing technology has been applied in the development and discovery of single nucleotide polymorphism (SNP) markers in fish. In this study, a panel of 120 expressed sequence tag (EST)-derived SNPs was selected by several selection filters from the resultant EST library of Odontobutis potamophila using Illumina Sequencing. In total, 37 SNPs from 120 putative SNPs were considered as the true SNPs using Sanger sequencing. For each SNP locus of 30 individuals of one wild population of O. potamophila that was successfully calculated, the number of alleles per locus was 2 with an observed heterozygosity of 0.0000-0.9000 and an expected heterozygosity of 0.1000-0.5263. A total of 33 loci conformed to Hardy-Weinberg equilibrium (HWE), and 4 loci deviated from HWE after Bonferroni correction. These 33 SNP markers will benefit the studies of population genetic structure, population evolution analysis, and construction of a high-density linkage map of O. potamophila.

A double-blind comparative study of Chinese herbal medicine Jinlianqingre Effervescent Tablets in combination with conventional therapy for the treatment of uncomplicated hand, foot, and mouth disease.

Chinese herbal medicine Jinlianqingre Effervescent Tablets (JET) are the recommended control measure for uncomplicated hand, foot, and mouth disease (HFMD) by the Ministry of Health of China. However, high-quality evidence to support this recommendation is limited. A total of 288 patients ranging in age from 1 to 13 years were randomly assigned to JET in combination with conventional therapy (mainly including the reduction of temperature by applying physical cooling paste or warm bathing), or conventional therapy with placebo group for 7 days. The objective was to test the hypothesis that JET combination therapy is more effective than conventional therapy for uncomplicated HFMD. A randomized, double-blind, placebo-controlled trial was designed. Our study showed that, compared with conventional therapy, the median time to fever resolution was significantly shorter in the JET combination therapy (8 vs. 80 h; p < 0.0001); the risk of fever resolution increased in the JET combination therapy [hazard ratio, 19.8; 95% confidence interval (CI), 12.8 to 30.7]; the median healing time of rash or oral ulcer was significantly shorter in the JET combination therapy (14 vs. 74 h; p < 0.0001); and the median symptom score for skin or oral mucosa lesions improved more rapidly in the JET combination therapy during the follow-up period. The median duration of hospital stay was 6 days in the JET combination therapy and 7 days in the conventional therapy (p < 0.0001). No significant adverse events and complications were found in both groups. The addition of JET to conventional therapy reduced fever clearance time, healing time of skin or oral mucosa lesions, and duration of hospital stay in children with uncomplicated HFMD.

Preparation of drug-loaded chitosan microspheres repair materials.

OBJECTIVE: With the development of society and the progress of science and technology, microspheres, as a new polymer material, have been applied to all aspects of human beings. Microspheres can play a huge role in food safety, electronic technology, sewage treatment, biomedicine, etc., and are non-toxic or harmless. There are three main types of substrates for the preparation of microspheres: natural polymers, semi-synthetic polymer materials, and synthetic polymer materials. MATERIALS AND METHODS: In this study, the inorganic material kaolin was modified by the emulsification-crosslinking method with chitosan and composite microspheres with large interlayer spacing were prepared, which were characterized by Fourier Transform Ioncyclotron Resonancel (FTIR) analysis and Scanning Electron Microscope (SEM). The prepared kaolin/chitosan microspheres were then placed in different amounts of aspirin and the optimal dose was investigated by encapsulation efficiency and drug loading rate. The drug release rate of 0.5 h, 1 h, 1.5 h, 2 h, 4 h, 6 h, and 12 h was then determined by simulating the human colon to determine the performance of the sustained-release drug. RESULTS: The experimental results showed that after the prepared composite microspheres were loaded with aspirin drug, we got the optimal dosage of 0.1 g by discussing the encapsulation efficiency and drug loading rate of the drug-loaded microspheres, and the encapsulation efficiency reached 80.80%, while the drug loading rate was 24.40%, the drug release capacity reached about 83% in about 12 hours. CONCLUSIONS: The research shows that the kaolin/chitosan drug-loaded microspheres prepared by the emulsification and cross-linking method are excellent drug-loading materials.

The effectiveness of using platelet-rich concentrate with iliac bone graft in the repair of alveolar cleft: a meta-analysis of randomized controlled trials.

The purpose of this study was to review the existing evidence from randomized controlled trials (RCTs) on the effect of autogenous bone grafts combined with a platelet-rich concentrate on alveolar clefts. An electronic search was conducted in the PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Embase, and ClinicalTrials.gov databases for studies published between January 2000 and April 2022. This study included six RCTs to evaluate bone quantity (bone formation ratio, %) and quality (bone density in Hounsfield units, HU), as well as complications as a way to assess the safety of the technique. Two independent reviewers assessed the risk of bias. There was no statistically significant difference in bone formation ratio at 6 months of follow-up between the use of autologous bone alone for alveolar bone grafting or adding platelet-rich plasma (PRP) (mean difference (MD) 14.33%, 95% confidence interval (CI) - 7.19% to 35.85%; P = 0.196) or platelet-rich fibrin (PRF) (MD 9.38%, 95% CI -2.36% to 21.12%; P = 0.123) to autologous bone. The MD for the change in bone density at 6 months was in favour of PRP added to autologous bone graft (MD 155.69 HU, 95% CI 99.29-212.09 HU; P < 0.001); however, this result was based on only two studies, one of which had a high risk of bias. Patients who received autologous bone graft with PRP were significantly less likely to experience complications (odds ratio (OR) 0.21, 95% CI 0.05-0.92; P = 0.038), but this was no longer statistically significant after a sensitivity test (OR 0.24, 95% CI 0.04-1.56; P = 0.138). In conclusion, this systematic review and meta-analysis appears to show no benefit to using a platelet-rich concentrate combined with autologous bone for alveolar cleft grafting in terms of bone volume, bone density, or complications.

[Three-dimensional finite element study on the effects of maxillary anterior two-step retraction and en-masse retraction with clear aligners].

Objective: To investigate the effects of two-step retraction and en-masse retraction on tooth movement pattern of anterior teeth and posterior anchorage with clear aligners using three-dimensional finite element analysis. Methods: A finite element model of maxillary first premolar extraction case undergoing clear aligner treatment was established based on maxillofacial cone-beam CT data of a 24-year-old adult male with individual normal occlusion, who visited Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine for impacted mandibular third molar in June, 2022. The initial tooth displacement of five anterior retraction protocols (two-step with canine retraction, two-step with incisor bodily retraction, two-step with incisor retraction-overtreatment, en-masse bodily retraction, and en-masse retraction-overtreatment) were evaluated. Results: Two step with canine retraction caused distal tipping of the canine and labial tipping of the incisors (0.18° for central incisor and 0.13° for lateral incisor). Two step with incisor retraction caused mesial tipping of the canine. In two step with bodily retraction protocol, uncontrolled lingual tipping was found in central incisor (0.29°) and lateral incisor (0.32°). In two-step with incisor retraction-overtreatment protocol, the movement pattern of the incisors didn't change, but the inclinations reduced to 0.21° and 0.18°. En-masse retraction caused distal tipping of the canine. In en-masse bodily retraction protocol, uncontrolled lingual tipping was also found in central incisor (0.19°) and lateral incisor (0.27°). In en-masse retraction-overtreatment protocol, the central incisor showed controlled lingual tipping (0.02°) and the lateral incisor showed palatal root movement (0.03° labial inclination). Posterior teeth exhibited mesial tipping in all five protocols. Conclusion: En-masse retraction with incisor overtreatment was beneficial to incisor torque control in clear aligner treatment.

[Application of three-dimensional visualized model of impacted tooth for surgical extraction in undergraduate oral experimental teaching].

Objective: To evaluate the effect of the application of a self-developed three-dimensional visualized model of impacted tooth for surgical extraction in undergraduate oral experimental teaching. Methods: Forty-one undergraduates majoring stomatology of Tongji University from 2018 [19 males and 22 females, aged (22.4±0.8) years] were enrolled and randomly divided into the conventional group and the experimental group. Students of the conventional group (21 students including 8 males and 13 females) received a teaching protocol for the surgical extraction of impacted tooth including theoretical lectures, watching operation videos, and operating on head-simulator teaching systems. Students of the experimental group (20 students including 11 males and 9 females) received an additional training of resistance assessment and surgical extraction using the three-dimensional visualized model of impacted tooth before operating on the head simulators. After class, a questionnaire survey was carried out among students, and the operation results on the head simulators were evaluated by the teacher. Results: The results of the questionnaire showed that the students in the experimental group were rated higher than those in the traditional group in terms of being able to imagine the relationship between impacted teeth and adjacent structures (U=114.00, P=0.006), avoiding damage to adjacent teeth (U=87.00, P<0.001) and inferior alveolar nerve during tooth extraction (U=111.50, P=0.006), and being more confident in clinical operations in the future (U=120.00, P=0.013). According to the evaluation results of tooth extraction on the head simulators, there was no significant difference in the operation time between the two groups (U=138.50, P=0.056). In the experimental group, 5% (1/20) caused adjacent tooth loosening and 15% (3/20) caused the excessive bone defect, which was less than those in the traditional group [38% (8/21) and 48% (10/21), respectively] (P=0.021; P=0.043). There was no significant difference in the incidence of grinding out the deep bone of impacted teeth between the two groups (P=0.232). Conclusions: The application of three-dimensional visualized model of impacted tooth for surgical extraction in undergraduate oral experimental teaching had achieved good results and was worth popularizing.

[Study of B10 cells in the pathogenesis of the interaction between chronic obstructive pulmonary disease and periodontal disease].

Objective: To determine the ratio of ingerleukin(IL)-10 secreting regulatory B cells (B10 cells) and the levels of IL-10 in peripheral blood of periodontitis patients with or without chronic obstructive pulmonary disease (COPD), and to explore the function of B10 cells in the pathogenesis of the interaction between COPD and periodontitis. Methods: Forty-five periodontitis patients and healthy people were recruited and divided into three groups: COPD group, COPD+periodontitis group and health controls with 15 people in each group. Peripheral blood samples were collected to determine the B10 population. Another group of 93 periodontitis patients and healthy people were also collected and divided into the same 3 groups with 31 people in each group. Peripheral blood samples were collected to determine the cytokine IL-10. Results: After stimulation with lipopolysaccharide (LPS)+phorbol-12-myristate13-acetate+ionomycin+brefeldin A (PIB) for 5 h, the ratio of B10 in COPD+periodontitis group [(0.44±0.11)%] was significantly lower than that in the control group [(0.63±0.14)%] and periodontitis group [(0.62±0.13)%] (P<0.01), respectively. The ratio of B10 cells showed no significant difference between periodontitis group and healthy control group (P>0.05). After stimulation with LPS+PIB for 48 h, the ratio of B10 cells in COPD+periodontitis group [(7.59±1.33)%] was significantly lower than that in the periodontitis group [(10.14±2.02)%] and the healthy controls [(11.80±1.71)%] (P<0.01), respectively. The ratio of B10 cells in periodontitis group was significantly lower than that in the healthy controls (P<0.05). The levels of IL-10 in periodontitis group [(2.55±0.61) ng/L] and COPD+periodontitis group [(1.95±0.45) ng/L] were significantly lower than that in the control group [(3.96±1.15) ng/L] (P<0.01) respectively. Moreover, the level of IL-10 in COPD+periodontitis group was significantly lower than that in the periodontitis group (P<0.01). Conclusions: The dysfunction of immune system caused by the decreased proportion of B10 cells might be involved in the pathological process of COPD promoted by periodontitis.

[Occlusal contact of primary dentition at intercuspal position in children with individual normal occlusion].

Objective: To record occlusal contact of primary dentition at maximal intercuspal position in children with individual normal occlusion. Methods: A total of 57 children were recruited from patients of the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology. Inclusion criteria were that the subjects were 3-5 years old with no visually detectable caries or pupal and periapical diseases, had complete primary dentition, had individual normal occlusion, had normal function of craniofacial system, were medically healthy, could cooperate with sampling and had obtained written informed consent from the parents or guardians. Finally, forty-seven children aged 3 to 5 years old were enrolled, including 24 males and 23 females. The age, height and weight of all subjects were (4.1±0.7) years old (ranging 3.0-5.8 years old), (103.7±7.2) cm (ranging 90-120 cm) and (17.1±2.5) kg (ranging 12.5-22.5 kg), respectively. Occlusal abilities such as occlusal contact area, average bite pressure, maximum bite pressure, maximum bite force and occlusal balance were measured with Dental Prescale Ⅱ system. Results: Maximum bite force and occlusal contact area at intercuspal position in children with primary dentition were (567.40±223.84) N (ranging 226.7-1 154.6 N) and (18.56±6.54) mm2 (ranging 8.4-41.2 mm2), respectively. There was a significantly strong correlation between maximum bite force and occlusal contact area (r=0.954, P<0.01). Height and weight of children were also positively correlated with their maximum bite force (r=0.397, P=0.022 and r=0.453, P=0.008, respectively). Maximum occlusal bite force and contact occlusal area of boys [(651.80±224.34) N and (20.77±6.97) mm2] were significantly higher and larger than those of girls [(479.34±190.45) N and (16.25±5.27) mm2] (P<0.05). Thirty-two of all 47 children had one occlusal contact point with maximum bite pressure, mostly locating within the primary molar region. Bite forces of anterior and posterior teeth of primary dentition were (124.12±56.99) N and (450.11±205.09) N, respectively, about (21.82±11.40)% and (71.80±21.35)% of maximum bite force of the whole primary dentition. All of the occlusal balance points located in posterior teeth regions. Occlusal contacts were observed at both anterior and posterior teeth of primary dentition with individual normal occlusion. Conclusions: There was a great variation of maximum bite forces of primary dentitions at intercuspal position of children with individual normal occlusion. Maximum bite force of primary dentition was significantly correlated with occlusal contact area, height and weight of children. Occlusal contact points with maximum bite pressure and occlusal bite balance points of primary dentitions mostly located in primary molar regions.

[Development of a deep learning based prototype artificial intelligence system for the detection of dental caries in children].

Objective: To develop a prototype artificial intelligence image recognition system for detecting dental caries, especially those without cavities, in children. Methods: Seven hundred and twelve intraoral photos, which were taken by dental professionals using a digital camera from October 2013 to June 2020 in the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, were collected from the children who received dental treatment under general anesthesia. The well-documented post-treatment electronic dental record of each child was identified as label standard to determine whether the teeth were carious and the type of caries types such as caries that had become cavities (caries with cavities), pit and fissure caries that had not become cavities (pit and fissure caries) and proximal caries which the marginal ridge enamel had not been destroyed (proximal caries). The various teeth and caries types were labeled by pediatric dentists using VoTT software (Windows 2.1.0, Microsoft, U S A). There were five labeled groups: pit and fissure caries, approximal caries, non-carious approximal surfaces, caries with cavities and teeth without caries (including intact fillings). Each group was randomly divided into training dataset, validation dataset and test dataset at a ratio of 6.4∶1.6∶2.0 by using random number table. After using the labeled training dataset for deep learning training, a deep learning-based artificial intelligence (AI) image recognition system for detecting dental caries was established, with the caries probability greater than 50.0% as the criterion for determining caries. Sensitivity and accuracy were used as indicators of recognition specificity. Results: Seven hundred and twelve single-jaw intraoral photographs were segmented and annotated into 953 pit and fissure caries, 1 002 approximal caries, 3 008 caries with cavities, 3 189 teeth without caries and 862 non-carious approximal surfaces, totaly 9 014 labels. The sensitivities and specificities of the test set were 96.0% and 97.0% for caries with cavities, 95.8% and 99.0% for pit and fissure caries and 88.1% and 97.1% for approximal caries. Conclusions: The current AI system developed based on deep learning of the intra-oral photos in the present study showed the ability to detect dental caries. Furthermore, the AI system could accurately verify different types of dental caries such as caries with cavities, pit and fissure caries and proximal caries.

[Evaluation of the effect of free fibular flap transplantation in repairing mandibular osteoradionecrosis defect in 151 cases].

Objective: To investigate the clinical effect of free fibula flap transplantation in repairing the defect of mandibular osteoradionecrosis (ORN). Methods: A total of 151 mandibular ORN patients undergoing free fibular flap transplantation were selected from August 2005 to September 2020 in the Department of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University. Among them, 109 patients were males and 42 patients were females, aged (54.1±10.1) (ranged 31-85) years old. The clinical data of the patients was collected and the survival rate of the flaps and postoperative function were calculated to evaluate the surgical efficacy. The χ2 test was used for difference analysis. Results: Among the 151 patients, mandibular ORN caused by radiotherapy for nasopharyngeal carcinoma accounted for 79.5% (120/151). The average time for mandibular ORN appeared was 5(6) years after radiotherapy. Facial artery [57.2%(87/152)] and superior thyroid artery [32.9%(50/152)] were the main anastomotic arteries in the recipient area. There was no significant difference in the necrosis rates of the two flaps [10.3%(9/87) and 12.5% (5/50), respectively, P=0.949]. The main anastomotic veins in the recipient area were the external jugular vein [48.4%(135/279)] and the common facial vein [26.5%(74/279)]. Twenty-five cases (16.6%) had one vein anastomosed, and 126 cases (83.44%) had two veins anastomosed. There was no significant difference in the flap necrosis rate between the two conditions [20.0%(5/25) and 7.1%(9/126), respectively, P=0.100]. Ninety-seven cases (64.2%) used the peroneal musculocutaneous-fascia composite flap to repair the maxillofacial soft and hard tissue defects. Thirteen cases (8.6%) underwent the restorations with digital virtual surgery design, of which 5 cases were repaired with dental implants at the same time. After the operations, lower respiratory tract infection occurred in 17 patients (11.3%), and upper respiratory tract obstruction occurred in 3 cases (2.0%). The survival rate of the flap after operation was 90.7% (136/151), and 21 patients (13.9%) had flap vascular crisis. Delayed healing of maxillofacial wounds occurred in 33 cases (21.9%). After 3 to 24 months of follow-ups, 110 patients (76.9%) had no fistula inside/outside the oral cavity, 118 patients (82.5%) had an improvement in opening mouth of increasing (≥0.5 cm) after surgery, 135 patients (94.4%) had pain relief, 97 cases (67.8%) could eat normal diet, semi-liquid or soft food, and 137 cases (95.8%) were satisfied or basically satisfied with the treatment effects. Conclusions: The free fibular flap transplantation is an effective method to repair mandibular ORN defects. Preoperative vascular assessment is helpful for the selection of recipient vessels. Facial artery, superior thyroid artery, external jugular vein and common facial vein can be used as the main recipient vessels. The repair of the peroneal musculocutaneous-fascia composite flap facilitates the closure of internal and external fistulas. Digital technology can help to restore the maxillofacial shape more accurately, improve the patient's occlusal and chewing function and enhance the quality of life of mandibular ORN patients.

[Pattern of sugar-sweetened beverages consumption-based on group-based trajectory modeling and its association with childhood periodontal health].

Objective: To explore the prospective association between consumption pattern of sugar-sweetened beverages and childhood periodontal health. Methods: This study was based on a 4-year longitudinal cohort of children from Bengbu, Anhui province. Pattern of sugar-sweetened beverages was determined by group-based trajectory modeling (GBTM) through annual child-reported questionnaire. Association between sugar-sweetened beverages pattern with plague index and gingivitis was explored through multivariate linear and logistic regression. Results: A total of 997 children including 418 boys and 579 girls were included in this study, with an average age of (11.00±0.70) years at the final wave. Four consumption patterns on sugar-sweetened beverages were identified by GBTM: persistent low group (80.70%), gradually decreasing group (12.40%), decreasing after increasing group (2.20%) and gradually increasing group (4.70%). Compared with the persistent low group (1.08±0.70), the Plague index among gradually increasing group (1.73±0.80) was significantly higher (t=4.00, P<0.001). The prevalence of gingivitis was significantly higher among children in the gradually increasing group (12.80%) than that in the persistent low group (3.00%) (χ(2)=12.40, P<0.001). After controlling for related confounders, results suggested that Plague index increased by 0.58 (95%CI: 0.27-0.89) and 0.38 (95%CI: 0.03-0.73) in the gradually increasing group and "decreasing follow the increase" group, respectively when compared with the persistent low group. The risk for gingivitis was 4.42 times (95%CI: 1.65-12.20, P=0.003) higher in the gradually increasing group. Conclusion: Our data suggested that children with higher sugar-sweetened beverages consumption during the transition period from childhood to adolescence were under higher risk for periodontal diseases.

[Study on the influence of sleeve height and implant length on accuracy of static computer-assisted implant surgery].

Objective: To evaluate the influence of the sleeve lengths and implant lengths on accuracy of static computer-assisted implant surgery (sCAIS). Methods: Twenty-eight models of bilateral mandibular single tooth loss were included. Fifty-five implants were placed under the guidance of sCAIS (Straumann Bone Level 4.1 mm×10 mm). According to the height of metal sleeve of static guide plate, 55 implants were divided into 11 groups (free hand group, 1 mm group, 2 mm group, 3 mm group, 4 mm group, 5 mm group, 6 mm group, 7 mm group, 8 mm group, 9 mm group, 10 mm group), with 5 implants in each group. Eight research models were included. Group with 5 mm sleeve guides were used to place implants of different length, (Straumann Bone Level width 4.1 mm, height was 8 mm, 10 mm and 14 mm), 5 implants in each group. Eighteen patients with mandibular single tooth loss were included in the Department of Oral Implantology, Tianjin Stomatological Hospital from October 2018 to June 2019. There were 10 males and 8 females, 18-46(33.7±7.9) years old. A total of 18 implants were implanted and divided into 3 groups (free hand group, 3 mm group and 5 mm group) with 6 implants in each group. Digital software was used to compare the implant positions before and after implantation. Non-parametric Kruskal-Wallis test or one-way ANOVA were used to analyze the results. Results: There was no significant difference in implant vertical deviation between different sleeve height groups (1-10 mm) and free hand group, but the neck deviation in free hand group[(1.04±0.13) mm] was significantly higher than that in different sleeve height groups (1-10 mm) (P<0.05). The tip deviations of free hand group, 1 mm group and 2 mm group [(1.32±0.43), (0.83±0.10) and (0.78±0.11) mm, respectively] was significantly higher than that of 10 mm group [(0.31±0.14) mm](P<0.05). The angle deviation of free hand group and 1 mm group (3.99°±0.85° and 2.59°±0.69°), respectively] was significantly higher than that of 10 mm group (0.61°±0.03°) (P<0.05). The tip deviations of implants in the 14 mm group [(0.83±0.22) mm] was significantly higher than that in the 8 mm and 10 mm groups [(0.44±0.07) and (0.49±0.06) mm, respectively]. Clinical studies showed that there was no significant difference in neck deviation, tip deviation and angle deviation between 3 mm group and 5 mm group (P>0.05), but deviations were significantly lower than those in free hand group (P<0.05). Conclusions: The length of the sleeves has significant influence on the accuracy of the surgical guide. There was no significant difference in accuracy of the implant guide with 3 mm or 5 mm metal sleeves. The vitro study has some limitations and needs further systematic research.

Combination of biomechanical evaluation and accurate placement of dental implants: a new concept of virtual surgery in maxillary and mandibular functional reconstruction.

Biomechanics are crucial for bony regeneration and survival of implants in functional maxillary and mandibular reconstructions. However, we know of no study that has included an analysis of biomechanics to guide the optimal position of a fibular graft in virtual surgery. This study was designed to evaluate the combination of biomechanics and accurate placement of implants for virtual surgery in reconstruction of the jaw using fibular grafts. Thirty-one patients had maxillary or mandibular reconstruction with vascularised fibular grafts and the immediate placement of dental implants. Virtual studies were made preoperatively to evaluate the biomechanics and to assess the position of the fibular grafts with minimal distribution of stress. All operations proceeded accurately and with no complications with a mean (range) of 14 (6-20) months' follow-up. According to the individual biomechanical evaluations, the optimal position for the fibular graft is probably the middle of the mandibular body or below the bottom of the maxillary sinus. The combination of biomechanical evaluation and accurate placement of dental implants is a new concept that could achieve good biomechanical positioning of fibular grafts in the jaw and a desirable level of accuracy for functional reconstruction.

[Pilot study of trans-oral ultrasonography of temporomandibular joint in oblique sagittal plane].

This pilot study aimed to investigate the feasibility of trans-oral ultrasonography of the temporomandibular joint (TMJ) in oblique sagittal plane. Six volunteers who were receiving residency training at Hainan Hospital of General Hospital of Chinese PLA were recruited into this study, five of them had normal TMJ and one had anterior displaced disc all of which had been confirmed by MRI. A hockey-stick-shaped ultrasound probe was placed between the cheek and maxilla to push against the mucosa lateral to posterior maxillary tuberosity, and every volunteer underwent bilateral scans. The sonographic imaging were completed successfully on the six volunteers; the condyle, the superior and the inferior head of the lateral pterygoid muscle, the disc and the maxillary vein were clearly identified in all the twelve ultrasonographic scans. The feasibility of trans-oral ultrasonography of TMJ in oblique sagittal plane was confirmed.