Identification the Low Oxidative Stress Subtype of Periodontitis.

OBJECTIVE: The aim of this research was to identify the low oxidative stress-related genes expression (L-OS) subtype in patients with periodontitis. METHODS: Microarray data (MA) were retrieved from the Gene Expression Omnibus database. The different oxidative stress (OS) subtypes of periodontitis were identified by K-means clustering analysis and gene set variation analysis (GSVA). Differentially expressed genes (DEGs) (|Log fold change (FC)| >1, q < 0.05) amongst the OS subtypes and healthy controls (HCs) were identified by Limma R package. The genomic feature of L-OS subtype and corresponding medicines were evaluated and visualised with Drug-Gene Interaction Database and cytoscape-v3.7.2 software (Pearson correlation coefficient > 0.4). Finally, the LASSO-Logistic regression model was adopted to evaluate and predict patients' OS phenotype in routine clinical practice. RESULTS: The 241 periodontitis samples and 69 HCs were included. Thirty-three DEGs between the L-OS and high oxidative stress-related genes expression (H-OS) subtypes and 96 DEGs, including 8 transcription factors, between L-OS subtype and HCs were identified, respectively. Then, the network of TFs-Genes-Drugs was constructed to determine genomic feature of L-OS subtype. Finally, a 4-gene signature formula and the cutoff value were identified by ML with LASSO model to predict patients' classification. CONCLUSIONS: For the first time, we identified L-OS subtype of periodontitis and evaluated its genomic feature with MA.

[Effect of Twin-block in adolescents with mandibular retrusion and normal anterior overjet].

PURPOSE: To investigate the therapeutic effect of modified fixed Twin-block on patients whose mandible was retruded and anterior overjet was normal. METHODS: Thirty-six adolescents with mandibular retrusion and normal anterior overjet were selected. The goal of occlusal reconstruction was to move the soft tissue pogonion forward to the zero meridian(0°). Fixed Twin-block combined with the mini-implants on the mandibular buccal shelf was used to promote mandibular growth. After 12 months, the appliances were removed step by step to observe the stability of the jaw relationship. Fixed orthodontic treatment was performed to achieve ideal occlusion and coordinated profile. SPSS 13.0 software package was used for Student's t test. RESULTS: The length of mandibular body increased significantly which facilitated the forward movement of the soft tissue pogonion, and the profile changed from convex to straight. Comparison of the results before and after Twin-block treatment showed that Co-Gn, SNB, U1-SN, U6-0°, U1-0°, U1-L1, anterior overbite, anterior overjet, Pog's-0°, L1-0° and lower anterior facial height changed significantly (P＜0.05). Comparison of the results before and after fixed orthodontic treatment showed that PP-MP, SN-MP, U6-0°, IMPA, L1-0°,U1-SN, U1-L1, anterior overbite and overjet changed significantly(P＜0.05). CONCLUSIONS: Modified fixed Twin-block combined with mini-implants on the mandibular buccal shelf can effectively stimulate the mandibular growth and improve the lateral profile of patients with mandibular retrusion and normal overjet.

[Study on digital models of normal deciduous dentition in 189 children from Shanghai].

PURPOSE: To study the gender difference and the regulation of growth and development in normal deciduous dentition． METHODS: A total of 189 children with normal deciduous dentition aged 3 to 6 years in several kindergartens in Xuhui District in Shanghai were selected. The three-dimensional(3D) digital dental models were reconstructed by intraoral scanning. Geomagic Studio, a 3D reverse engineering software, was employed to extract the data, such as the dental arc perimeter of C(APC), the dental arc perimeter of E(APE), the dental arc length of C(LC), the dental arc length of E(LE), the dental arc width of C(C-C), the dental arc width of E(E-E), the mesiodistal width of the deciduous crown, the maxillary and mandibular space. SPSS 22.0 software package was used for data analysis. RESULTS: Parameters of deciduous dentition in boys were significantly elevated than in girls(P＜0.05). All the boys and girls were divided into 4 groups by age. In 3-year-old group, significant differences were observed in maxillary APC, C-C, E-E(P＜0.05) between boys and girls. In 4-year-old group, all boys' parameters were significantly greater than girls'(P＜0.05) except maxillary LC. In 5-year-old group, there were significant differences in all the parameters between boys and girl(P＜0.05) except maxillary APE and mandibular APC, LC, LE, C-C. No significant difference was observed in all the parameters except mandibular APE in 6-year old group. The significant difference between boys and girls were observed in the mesiodistal width of each deciduous crown except that of the maxillary lateral incisor and mandibular central incisor (P＜0.05). There were significant differences in maxillary LE and E-E among children of different ages(P＜0.05).The maxillary space was significantly greater than the mandibular space(P＜0.01). CONCLUSIONS: There was gender difference in children's normal deciduous dentition, especially when they were 4 years old.

An injectable hydrogel combining medicine and matrix with anti-inflammatory and pro-angiogenic properties for potential treatment of myocardial infarction.

One of the main illnesses that put people's health in jeopardy is myocardial infarction (MI). After MI, damaged or dead cells set off an initial inflammatory response that thins the ventricle wall and degrades the extracellular matrix. At the same time, the ischemia and hypoxic conditions resulting from MI lead to significant capillary obstruction and rupture, impairing cardiac function and reducing blood flow to the heart. Therefore, attenuating the initial inflammatory response and promoting angiogenesis are very important for the treatment of MI. Here, to reduce inflammation and promote angiogenesis in infarcted area, we report a new kind of injectable hydrogel composed of puerarin and chitosan via in situ self-assembly with simultaneous delivery of mesoporous silica nanoparticles (CHP@Si) for myocardial repair. On the one hand, puerarin degraded from CHP@Si hydrogel modulated the inflammatory response via inhibiting M1-type polarization of macrophages and expression of pro-inflammatory factors. On the other hand, silica ions and puerarin released from CHP@Si hydrogel showed synergistic activity to improve the cell viability, migration and angiogenic gene expression of HUVECs in both conventional and oxygen/glucose-deprived environments. It suggests that this multifunctional injectable CHP@Si hydrogel with good biocompatibility may be an appropriate candidate as a bioactive material for myocardial repair post-MI.

The Relationship between the Serum NLRP1 Level and Coronary Lesions in Patients with Coronary Artery Disease.

Background: The pathogenesis of coronary artery disease is complex, and inflammation is one of the regulatory factors. The nucleotide-binding oligomerization domain (NOD)-like receptor protein 1 (NLRP1) plays an important role in the cellular inflammatory response, cell apoptosis, cell death, and autoimmune diseases. Whether the level of NLRP1 is related to the severity of coronary artery stenosis in patients with coronary artery disease (CAD) has not been reported. Objective: To test the serum level of NLRP1 in unstable angina (UA) patients and investigate the effect of NLRP1 on coronary stenosis severity of the coronary artery disease (CAD). Methods: 307 patients hospitalized in the Department of Cardiology of the Affiliated Hospital of Xuzhou Medical University for coronary angiography from January 1, 2021, to December 31, 2022 were included. We detect the level of NLRP1 in the serum of the included patients. Patients were divided into UA group and control group according to coronary angiography results and other clinical data. We use logistic regression to screen the influencing factors of UA. Then, subgroups were divided according to the Gensini score and the number of coronary artery lesions, and the difference of serum NLRP1 level between the groups was compared. Spearman correlation analysis was used to explore the correlation between the serum NLRP1 level and Gensini score. We analyze the diagnostic value of NLRP1 for UA by drawing ROC curve. Results: The median level of serum NLRP1 in patients with UA (n = 257) was 49.71 pg/ml, IQR 30.15, 80.21, and that in patients without UA (n = 50) was 24.75 pg/ml, IQR 13.49, 41.95. Serum NLRP1 levels were significantly different among different subgroups. The patient's Gensini score was correlated with the patient's serum NLRP1 level. Conclusion: The serum NLRP1 level is increased in patients with UA, which is increased with the increasing severity of coronary lesions.

Construction of ZnO/PCL Antibacterial Coating Potentially for Dental Unit Waterlines.

The formation of bacterial biofilms and the contamination of treatment water within dental unit waterlines can lead to a risk of secondary bacterial infections in immunocompromised patients. Although chemical disinfectants can reduce the contamination of treatment water, they can also cause corrosion damage to dental unit waterlines. Considering the antibacterial effect of ZnO, a ZnO-containing coating was prepared on the surface of polyurethane waterlines using polycaprolactone (PCL) with a good film-forming capacity. The ZnO-containing PCL coating improved the hydrophobicity of polyurethane waterlines, thus inhibiting the adhesion of bacteria. Moreover, the continuous slow release of Zn ions endowed polyurethane waterlines with antibacterial activity, thus effectively preventing the formation of bacterial biofilms. Meanwhile, the ZnO-containing PCL coating had good biocompatibility. The present study suggests that ZnO-containing PCL coating can realize a long-term antibacterial effect on the polyurethane waterlines by itself, providing a novel strategy for the manufacture of autonomous antibacterial dental unit waterlines.

Buccal rotation for wholly impacted maxillary third molar extraction.

BACKGROUND: Extracting wholly impacted maxillary 3rd molars faces difficulty due to the narrow surgical field, adjacent teeth resistances and risk of oroantral communication. This study is designed to introduce and evaluate the applicability of a novel method-buccal rotation to extract maxillary 3rd molars. MATERIALS AND METHODS: In this cohort study, from October 1st 2020 to September 30th 2021, 72 wholly impacted maxillary 3rd molars were included. Based on the crowns with coronal 1/3, middle 1/3, apical 1/3 of the adjacent teeth roots, teeth were classified into position I, II, III. Based on the angles < 30°, ≥ 30°but < 60°, ≥ 60° to the adjacent teeth, teeth were classified into angulation A, B, C. Traditional method and novel method-buccal rotation were applied based on the surgical simulations. Surgical results were recorded. To analyze the data, Chi-square test was applied. RESULTS: 82.00% of teeth in position I and 50.00% in position II were designed to use traditional method, 83.33% in position III were using the novel method (p < 0.05). 81.25% of teeth in angulation A and 52.63% in angulation B were designed to use traditional method, 80.00% in angulation C were using the novel method (p < 0.05). Four cases got temporary complications. CONCLUSION: Buccal rotation was applicable to extract the deep impacted maxillary third molars with large angles towards the adjacent teeth.

[Oral health behavior and parental cognition of first-grade children in urban and suburban areas of Shanghai].

PURPOSE: To investigate oral health behaviors of first-grade school children and parents' cognition of oral health in urban and suburban areas of Shanghai, and to analyze and compare the differences between the two areas, so as to provide reference for formulating oral health intervention measures and oral health education. METHODS: A total of 3 312 first-grade school-aged children in Shanghai were included by cluster random sampling method. Relevant data were collected through questionnaire survey of parents' oral health and clinical oral examination of children. Chi-square test was used to compare the differences in oral health behaviors of children and parents' oral health cognition between urban and suburban area with SAS 9.4 software package. RESULTS: The proportion of children who brush their teeth more than twice a day in urban and suburban areas was 72.55% and 44.26%, and the proportion of children who brushed their teeth with fluoride toothpaste was 53.25% and 44.79%, respectively. Compared with the suburban area, the brushing habits of school-aged children in urban area were better, the difference was statistically significant(P＜0.05). In terms of medical habits, the proportion of children with no dental experience in urban and suburban areas was 26.99% and 44.08%, and the proportion of children with toothache in the past year was lower than that in the last dental visit, the difference was statistically significant (P＜0.05). In terms of parents' cognition and attitude towards oral health knowledge, parents in urban areas were more correct than those in suburban areas, with the average correct rate being 82.56% and 70.42%, and the difference was statistically significant (P＜0.05). CONCLUSIONS: There are regional differences in oral health behaviors of first-grade school children and parents' oral health knowledge between urban and suburban area in Shanghai. It is suggested that relevant government departments should strengthen oral health education and oral health behavior guidance for parents, and strengthen oral health investment in non-central urban areas.

20 abnormal metabolites of Stage IV Grade C periodontitis was discovered by CPSI-MS.

Saliva is a noninvasive biofluid that contains the metabolic signature of severe periodontitis (SP, Stage IV and Grade C). Conductive polymer spray ionization mass spectrometry (CPSI-MS) was used to record a wide range of metabolites within a few seconds, making this technique a promising point-of-care method for the early detection of SP (Stage IV and Grade C). Saliva samples from 31 volunteers, consisting of 16 healthy controls (HC) and 15 patients with SP (Stage IV and Grade C), were collected to identify dysregulated metabolites. Twenty metabolites were screened out, including seven amino acids. Moreover, the results showed that amino acid metabolism is closely related to the development of periodontitis. The present study further confirmed that salivary metabolites in the oral cavity were significantly altered after plaque removal. These results suggest that the combination of CPSI-MS is a feasible tool for preclinical screening of SP (Stage IV and Grade C).

KLF9 Aggravates Streptozotocin-Induced Diabetic Cardiomyopathy by Inhibiting PPARγ/NRF2 Signalling.

AIMS: Krüppel-like Factor 9 (KLF9) is a transcription factor that regulates multiple disease processes. Studies have focused on the role of KLF9 in the redox system. In this study, we aimed to explore the effect of KLF9 on diabetic cardiomyopathy. METHODS AND RESULTS: Cardiac-specific overexpression or silencing of KLF9 in C57BL/6 J mice was induced with an adeno-associated virus 9 (AAV9) delivery system. Mice were also subjected to streptozotocin injection to establish a diabetic cardiomyopathy model. In addition, neonatal rat cardiomyocytes were used to assess the possible role of KLF9 in vitro by incubation with KLF9 adenovirus or small interfering RNA against KLF9. To clarify the involvement of peroxisome proliferator-activated receptors (PPARγ), mice were subjected to GW9662 injection to inhibit PPARγ. KLF9 was upregulated in the hearts of mice with diabetic cardiomyopathy and in cardiomyocytes. In addition, KLF9 overexpression in the heart deteriorated cardiac function and aggravated hypertrophic fibrosis, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. Conversely, cardiac-specific silencing of KLF9 ameliorated cardiac dysfunction and alleviated hypertrophy, fibrosis, the cardiac inflammatory response and oxidative stress. In vitro, KLF9 silencing in cardiomyocytes enhanced inflammatory cytokine release and oxidative stress; KLF9 overexpression increased these detrimental responses. Moreover, KLF9 was found to regulate the transcription of PPARγ, which suppressed the expression and nuclear translocation of nuclear Factor E2-related Factor 2 (NRF2). In mice injected with a PPARγ inhibitor, the protective effects of KLF9 knockdown on diabetic cardiomyopathy were counteracted by GW9662 injection. CONCLUSIONS: KLF9 aggravates cardiac dysfunction, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. KLF9 may become a therapeutic target for diabetic cardiomyopathy.

[Clinical efficacy of the combination of miniscrew with clear aligner in controlling the roller coaster effect].

PURPOSE: To investigate the clinical efficacy of miniscrew in controlling the roller coaster effect in long-distance space closure with clear aligner. METHODS: Sixteen adult patients with bimaxillary protrusion were selected. All cases were treated with clear aligner and their four first premolars were extracted. G6 was designed in all cases. In the experimental group, four miniscrews were inserted at the beginning of treatment to control the teeth in three dimensions; while in the control group, the miniscrews were not applied until obvious roller coaster effect appeared. Paired t test was used to analyze the data with Graphpad Prism 6.0 software package. RESULTS: All the extraction space was closed successfully and the lateral profile was improved significantly. The torque of the upper incisor was under well control and no roller coaster effect happened in the experimental group; while in the control group, the lingual inclination of the upper incisors and open bite of the posterior teeth developed(P＜0.05). After the miniscrews intrusion of the upper anterior teeth, the occlusion relationship improved significantly. CONCLUSIONS: Miniscrews effectively prevents and eliminates the roller coaster effect in the process of long-distance space closure with clear aligner.

Influence of different base materials and thicknesses on the fracture resistance of endocrown: A three-dimensional finite element analysis.

INTRODUCTION: To analyze the stress distribution of the all-ceramic endocrown with different base materials and thicknesses using three-dimensional finite element analysis. METHODS: A endodontically treated maxillary premolar was scanned by micro-CT, a three-dimensional finite element model of the endocrown with fluid resin as the base material was divided into control (0 mm), 1 mm, 2 mm, and 3 mm groups according to base thickness. Three kinds of conventional base materials were used and divided into glass ion group (A), fluid resin group (B), and nanocomposite resin group (C), and a three-dimensional finite element model of the endocrown with 1.0 mm thickness of base was established. A static loading with axial and 45° direction was applied to each model, the stress distribution of each part of the endocrown was analyzed under different base materials and thicknesses. RESULTS: The different thickness of the base layer has an influence on the components of the restoration and the tooth. The stress in the control group was the largest. The stress was the lowest when the thickness of the base layer was 1 mm; The maximum of the equivalent stress, the first, second, and third principal stress in the endocrown, abutment, and alveolar bone, are basically the same with the different base materials. The stress on the base layer increases with the elastic modulus of base materials increases. CONCLUSIONS: The base layer played a force buffering effect on the dental body restored with endocrowns, and the effect was the best at 1 mm; The selection of base material has little influence on the whole, but in order to protect the weak tissues of the cavity bottom, the base material with lower elastic modulus can be used.

A superlattice composite of Zn-Fe layered double hydroxide and graphene oxide for antitumor application.

A superlattice composite of Zn-Fe layered double hydroxide and graphene oxide was fabricated on the titanium surface and showed lamellar morphology. It was found for the first time that this superlattice composite could inhibit cell adhesion and proliferation, and cause cell death of the cholangiocarcinoma cell line RBE cells in vitro and show tumor inhibition effect in vivo.

Air Pollution and Workplace Choice: Evidence from China.

Understanding the impacts of air pollution on public health and individual behavior is crucial for optimal environmental policy design. Using 2015 census microdata in China, this paper examined the causal effect of air pollution on working place choice. The research design relies on a regression discontinuity design based on China's Huai River Policy. The discontinuity in air pollution caused by the Huai River Policy provides a natural experiment to estimate the impact of air pollution. The results show that air pollution significantly increases the possibility of individuals working near home. The positive effect of air pollution on working near home is more significant for women, the elderly, urban individuals and those individuals working in secondary and tertiary industries. This study improves our understanding of the health effects and avoidance behavior associated with environmental hazards, discusses the negative impact of air pollution on labor mobility and mismatch by making individuals work nearby, and emphasizes that strengthening air pollution control should be a long-term policy.

Lactobacillus helveticus Prevents Periodontitis Induced by Aggregatibacter actinomycetemcomitans in Rats by Regulating ß-Defensins.

Objective: To study the preventive effect of Lactobacillus helveticus (L. helveticus) on periodontitis induced by Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in rats. Methods: Eighteen 8-week-old female rats were randomly divided into three groups: Sham group, Trehalose group, and L. helveticus SBT2171 (LH2171) group. We measured the distance of the cementoenamel junction-alveolar bone crest (CEJ-ABC) to evaluate alveolar bone resorption. Hematoxylin-eosin staining was used to observe the histopathological changes of rat hemimaxillary tissues. We detected the expression of ß-defensins, tumor necrosis factor-α (TNF-α), interleukin- (IL-) 1ß, and IL-6 and the number of A. actinomycetemcomitans in rat gingival tissues by quantitative reverse transcriptase polymerase chain reaction. The levels of IL-1ß, IL-6, and TNF-α in rat gingival tissues were also measured by enzyme-linked immunosorbent assay. Results: Compared with the Trehalose group, the distance of CEJ-ABC was prominently reduced and alveolar bone resorption was notably improved in the LH2171 group. And the infiltration of inflammatory cells in the hemimaxillary tissue decreased obviously, periodontal fibers were arranged neatly, connective tissue small blood vessels proliferated, and the number of A. actinomycetemcomitans reduced significantly in the LH2171 group. In addition, the mRNA expression and release of inflammatory factors in the gingival tissues in the LH2171 group were notably lower than those in the Trehalose group. On the 21st and 36th day, the expression of ß-defensins in the gingival tissue of the LH2171 group increased significantly. Conclusion: L. helveticus improves alveolar bone resorption and increases the expression of ß-defensins thereby inhibiting the number of A. actinomycetemcomitans and thus prevents periodontitis.

[Enhanced mechanical properties and cytocompatibility of GelMA hydrogels by incorporating graphene oxide].

PURPOSE: To construct graphene oxide/methacrylated gelatin(GO/GelMA) hydrogel and to investigate its mechanical property and biocompatibility. METHODS: 50, 100, 200 µg/mL GO was added to GelMA and mixed thoroughly. The micromorphology of hydrogels was observed under scanning electron microscope(SEM). Compression text was used to assess lastic modulus, CCK-8 and live/dead cell staining was conducted to assess the viability of rat bone marrow-derived mesenchymal stem cells (rBMSCs). The data were analyzed using SPSS 23.0 software package. RESULTS: SEM showed a highly porous structure of the hydrogel. After adding GO, the elastic modulous increased (100, 200 µg/mL), swelling ratio increased(100 µg/mL) and expansion ratio decreased(200 µg/mL). The viability increased in 50 µg/mL GO and decreased in 100 and 200 µg/mL GO. CONCLUSIONS: Proper concentration of GO can increase the mechanical property and biocompatibility. 50 µg/mL GO/GelMA was suggested in bone tissue engineering given priority to biocompatibility.

Andrographolide-loaded solid lipid nanoparticles enhance anti-cancer activity against head and neck cancer and precancerous cells.

BACKGROUND: Increasing evidence indicates that andrographolide (ADG) exhibits anti-cancer activity against various cancer cell lines. However, its high hydrophobicity and poor bioavailability restrict its clinical application as a chemopreventative agent. Previously, we have shown that ADG-loaded solid lipid nanoparticles (SLNs) significantly enhanced the bioavailability and anti-hyperlipidemic activity of ADG. OBJECTIVES: We aimed to investigate whether ADG-SLN enhanced the bioavailability and anti-cancer efficacy of ADG in the human immortalized oral epithelial (HIOEC), precancerous leukoplakia (Leuk1), HN6, and HN30 cells that represented an in vitro model of stepwise head and neck squamous cell carcinoma development. RESULTS: The 50% inhibitive concentration (IC50) of ADG-SLN was significantly lower than that of free ADG against HIOEC, Leuk1, and HN6 and HN30 cells. Moreover, ADG-SLN was more effective than free ADG in promoting cell cycle arrest and apoptosis. Importantly, intracellular absorption of ADG was significantly higher in HN6 cells treated with ADG-SLN compared with free ADG-treated cells. CONCLUSIONS: Our preliminary study demonstrates that ADG-SLN exhibits superior inhibitory activity against head and neck cancer and precancerous cells compared with free ADG. This effect is due to the higher efficiency of cellular uptake and intracellular absorption by ADG-SLN.

[Consistency of the landmark identification on two types of cephalograms from cone-beam CT].

PURPOSE: To study the landmark consistency on two types of cephalograms reconstructed from the data of cone-beam CT(CBCT). METHODS: CBCT data of 56 patients without teeth missing were uploaded into Dolphin software and transferred to the cephalograms. In the control group, the right half projection was taken while in the experimental group, the images achieved after 6 individual projections were managed to achieve the synthesized cephalograms. One experienced orthodontists traced the 23 frequently-used landmarks and the consistency was compared by means of Hotelling T2 test with SPSS 13.0 software package. RESULTS: The tracing of anterior nasal ridge, posterior nasal ridge, upper incisor root tip, lower incisor edge, lower incisor root tip and condyle showed significant difference(P<0.05). CONCLUSIONS: The synthesized cephalograms in the experimental group show the anatomical structure more precisely which is more beneficial to landmark identification.

[Clinical study of the effect of fixed Twin-block on adolescent skeletal Class â ¡ malocclusion].

PURPOSE: To evaluate the retention ability of fixed Twin-block appliance and its clinical effect on adolescent skeletal ClassⅡmalocclusion. METHODS: Twenty-six skeletal ClassⅡdivision 1 adolescents (M:12, F: 14; age:11~13 years, average: 11.8 years) were chosen and fixed Twin-block appliance was used to guide the mandibular protrusion for one year. Before and after treatment, cephalometric films were taken to observe the skeletal, dental and soft tissue changes. Graphpad Prism 6.0 software was used for Student's t test. RESULTS: There was no loosening or destruction of the appliance during the treatment and the profile of all cases was improved significantly. The indexes that showed significant difference(P<0.05) included the mandibular length and position (Co-Gn, SNB, ANB, Pog-VL, Pos-VL) , the inclination and position of the maxillary incisors(U1-VL, U1-SN), the sagittal position of the mandibular dentition(L1-VL, L6-VL). The indexes that showed insignificant difference(P>0.05) included the mandibular plane(MP-SN), the length and position of the maxilla (SNA, A-VL) , the vertical position of the maxillary incisor(U1-HL), the position of the maxillary posterior teeth(U6-VL, U6-HL), the mandibular incisor inclination(IMPA) and the vertical position of the mandibular dentition(L6-MP,L1-MP). CONCLUSIONS: Fixed Twin-block appliance can enhance the mandibular anchorage, effectively promote the mandibular growth and improve the facial profile.

Pathologies associated with the mandibular third molar impaction.

To evaluate the associations of impaction patterns of mandibular third molars (M3Ms) with pathologies caused by them. In this study, 262 patients with 432 impacted M3Ms who referred in Shanghai Xuhui District Center were reviewed. The pathologies include pericoronitis, mandibular second molar (M2M) caries, and M2M distal periodontal pathology. The impaction patterns of M3Ms and the pathologies were examined, while the M2M outcomes after surgeries were evaluated. A χ2 test was used to analyze the data, with a p value of <0.05 being considered statistically significant. Pericoronitis was the major symptom in all patients, whereas the propensities of M2M distal caries and periodontal pathologies increased in older patients. Soft tissue impacted and vertically angulated teeth were more associated with pericoronitis (p < 0.05); mesio-angular impacted teeth in less deep positions had greater risks of M2Ms distal caries (p < 0.05); mesio-angular and horizontal impacted teeth in relative deep positions were more likely to cause M2Ms distal periodontal pathologies (p < 0.05). Extractions of soft tissue impacted teeth in vertical angulations should be considered, while removals of mesially and horizontally angulated or bony impacted teeth could be delayed.