[A prospective cohort study on the effect of implant restoration following micro crestal flap-alveolar ridge preservation at molar extraction sockets with severe periodontitis].

Objective: To evaluate the survival rate, success rate, soft tissue conditions and marginal bone level changes of implants following micro crestal flap-alveolar ridge preservation at molar extraction sockets with severe periodontitis, compared to natural healing. Methods: From March 2015 to January 2017, patients scheduled for molar extraction as a consequence of severe periodontitis and planned implant-retained prostheses from Department of Periodontology Peking University School and Hospital of Stomatology were selected. A total of 40 molar extraction sockets from 40 patients received implant placement following micro crestal flap-alveolar ridge preservation or natural healing. The front consecutive 20 teeth were assigned to the natural healing group, and the back ones were assigned to the micro crestal flap-alveolar ridge preservation (MCF-ARP) group. The superstructures were placed 6 months later. Within 2 weeks (baseline) and 1, 2 and 3 years after implant crown restoration, modified plaque index, probing depth, modified bleeding index and keratinized tissue width were recorded every six months. Parallel periapical radiographs were taken to evaluate the peri-implant marginal bone level and to calculate marginal bone loss. Independent sample t test or Mann-Whitney U test were used to compare the differences in the above clinical and imaging indicators between the two groups. Results: The implant survival rate and success rate of the two groups were both 100% (20/20). There were no significant differences in the modified plaque index, probing depth, modified bleeding index, buccal keratinized tissue width and marginal bone loss between two groups at 1, 2 and 3 years after implant crown restoration (all P>0.05). Marginal bone loss was 0.22 (0.14, 0.34) mm in the natural healing group and 0.21 (0.12, 0.30) mm in the MCF-ARP group at a 3-year post-loading evaluation. Conclusions: Within the limitations of the present study, implants placed at ridge preserved and naturally healed molar extraction sockets with severe periodontitis demonstrate comparable clinical outcomes at a 3-year post-loading evaluation.

[Risk factors and prevention for implant treatment in patients with periodontitis].

In patients with periodontitis, due to problems of periodontal tissue infection as well as soft and hard tissues defects, it may lead to implant infection, gingival papilla loss, soft tissue recession and poor coordination with adjacent teeth. For such patients, periodontal infection should be actively controlled before dental implant therapy. In consideration of insufficient soft and hard tissues, alveolar ridge preservation and soft tissue augmentation procedure can be used to preserve or increase soft and hard tissues as much as possible. Multi-disciplinary treatment is often needed for occlusion problems and coordination with adjacent tooth. Periodontal maintenance treatment of implants and natural teeth is also necessary after implant therapy. This paper discussed these risk factors and strategies for prevention and control, in order to provide some clinical guidances for the implant treatment of periodontitis patients.

[Analysis of ultrasound images features and diagnostic model establishment of alveolar soft part sarcoma and intramuscular capillary-type hemangiomas].

Objective: The ultrasonography features of alveolar soft part sarcoma (ASPS) and intramuscular capillary-type hemangiomas (ICTH) were analyzed, and the diagnostic model of ASPS was established. Methods: A cross-sectional study was carried out. The clinical data of 52 patients [28 males and 24 females, aged (20.7±15.1) years] with pathologically confirmed ASPS and ICTH admitted to People's Hospital of Henan Province from January 2005 to February 2023 were included in the study. According to pathological types, the patients were divided into ASPS group and ICTH group. Clinical data of patients were retrospectively collected, and meaningful indicators in the univariate analysis were included in the regression analysis for screening. After comprehensive consideration of clinical significance and statistical significance, eligible indicators were selected for inclusion in the regression analysis. Binary logistic regression analysis was used to screen the factors that distinguished the pathological types of ASPS and ICTH, and the diagnostic model was established. The area under receiver operating characteristic (ROC) curve (AUC) was used to evaluate the diagnostic effectiveness of the diagnostic model in distinguishing ASPS from ICTH. Results: There were 20 patients in ASPS group, 10 males and 10 females, aged (26.9±13.5) years, and 32 patients in ICTH group, 18 males and 14 females, aged (16.8±15.0) years. The age difference between the ASPS group and the ICTH group was statistically significant (P<0.05), and there were statistically significant differences in the ultrasound imaging features of "clear boundary" "peripheral lobe" "thin blood vessels inside the lesion are straight and out of shape" "intra-lesion liquification" "peripheral thick blood vessels" and "peripheral muscle fiber disruption" between the two groups (all P<0.001).Variables with clinical and statistical significance were selected as independent variables. Binary logistic regression analysis showed that peripheral muscle fiber interruption (OR=97.358, 95%CI:6.833-1 387.249) and internal thin blood vessels were flat and out of shape (OR=0.052, 95%CI:0.003-0.921) was the correlation factor to distinguish the pathological types of ASPS and ICTH. Two ultrasonic image features of "peripheral muscle fiber interruption" and "internal thin blood vessels are straight and out of shape" were used to establish the diagnostic model. The sensitivity of "peripheral muscle fiber interruption" diagnostic model was 81.3%, and the specificity was 95.0%. The AUC was 0.811(95%CI: 0.761-0.954). The sensitivity, specificity and AUC of the diagnosis model of "internal thin vessels with flat misshape" were 90.0%, 96.9% and 0.934(95%CI: 0.830-0.984). The sensitivity, specificity and AUC of the combined diagnosis model of "peripheral muscle fiber interruption" and "internal thin blood vessel straight out of shape" were 96.9%, 90.0% and 0.974(95%CI:0.877-0.999). Conclusion: Ultrasonography can be used to distinguish ASPS from ICTH, and the combined diagnostic model based on the two ultrasonic imaging features of "peripheral muscle fiber interruption" and "internal thin blood vessel straight out of shape" can further improve the diagnostic efficiency.

[Analysis of the status of occupational disease prevention and control of enterprises in mining and manufacturing industries in China in 2019].

Objective: To analyze the status of prevention and treatment of occupational diseases among mining and manufacturing industries in China in 2019, provide the scientific basis for the formulation and revision of policies and standards of prevention and treatment of occupational diseases. Methods: In May 2022, Collecting data of a project named Surveillance of Occupational Hazards in the Workplace in 2019 through the National Surveillance System for Occupational Hazards in the workplace. Compare the status of prevention and treatment of occupational diseases in 63 563 enterprises of mining and manufacturing industries among different dimensions. Results: The training rate of managers was 76.17% and that of occupational health managers was 76.97%. The rate of reporting of occupational diseases hazardous items was 67.58%, the rate of launching of the detection of occupational hazards was 57.16%, and the rate of launching of occupational health examination was 62.42%. Excluding the distribution rate of dust mask, the installation rate of various occupational prevention facilities and the distribution rate of gas mask and hearing protector were less than 80%. The differences in all the indicators among different areas, enterprise scales, economic types were statistically significant (P<0.05) . Conclusion: There are still some enterprises which are relatively weak in the ability of the prevention and treatment of occupational diseases in China. Measures such as special support, guidance and strengthen supervision should be taken towards those enterprises toimprove the awareness of prevention and treatment of occupational diseases and the level of that.

[Analysis of dust and noise exposure levels in the mining industry from the national surveillance program in 2019].

Objective: To understand the exposure level of dust and noise in the mining industry and provide data support for revising policy for the prevention and control of occupational diseases. Methods: In May 2022, Data was collected through the National Surveillance Program for Occupational Hazards in the Workplace. Descriptive analysis was conducted for dust and noise levels by industry type and enterprise size from 7, 679 enterprises in the mining industry among 29 provincial regions nationwide. Results: The enterprises in the mining industry included in the National Surveillance Program for Occupational Hazards in the Workplace are mainly small and micro, accounting for 47.97% (3684/7679) and 30.00% (230/7679) respectively. The industry is mainly compred of employers in the non-metallic ming and beneficiation industry, accounting for 50.25% (3859/7679). Among the enterprises with silica dust, coal dust, and noise hazards, the proportion of enterprises where total dust concentration and noise intensity exceed the standard is higher than 50%. 30% of the posts are with an exposure level of silica dust, coal dust, and noise that exceeds the standard. The exceedance rate and the median of the time-weighted average concentration of total coal dust among large and medium-sized enterprises are higher than those among small and micro-sized enterprises (P<0.05) . Conclusion: The dust and noise hazards in the mining industry are lower than in the past in China, but more than 25% of workers are still at a high risk of occupational pneumoconiosis and noise deafness. Therefore, intervention and surveillance strategies should be strengthened in the future.

[Investigation and analysis of late reporting and under-reporting of occupational diseases from 2018 to 2020 in China].

Objective: To understand the late reporting and the under-reporting of occupational disease from 2018 to 2020 in China and analyze the causes, so as to provide scientific evidence for improving the quality of occupational disease reports in China, timely acquiring the incidence of occupational disease, and assessing the occupational hazards. Methods: From May to December 2021, A total of 320 occupational disease diagnostic institutions were selected for investigation. The original documents of occupational disease diagnosis cases from 2018 to 2020 were compared with the online reported cases, and late reported and under-reported cases of occupational disease were analyzed. Results: A total of 32207 diagnosed cases from 2018 to 2020 were investigated, including 28934 confirmed cases and 3273 cases without occupational disease. The overall late reported rate and under-reported rate of confirmed cases were 20.2% and 2.1%, respectively. There were significant differences in the rate of late reporting and under-reporting of occupational diseases in different regions and different types of diagnostic institutions (P<0.001). The southwest region had the highest rates of late reporting and under-reporting, 61.6% and 7.9% respectively. The late reported rate of all kinds of occupational diseases was about 15.0%, and the under-reported rate was from 1.5.0% to 5.0%. Conclusion: At present, the phenomenon of late reporting and under-reporting occupational diseases is still obvious. It is necessary to strengthen the inspection of occupational disease reporting, improve the quality of occupational disease reporting, and provide scientific basis for the formulation of occupational disease prevention and control policies.

[A summary on surveillance system of occupational disease under the framework of National Health Insurance Informatization Project].

The surveillance of occupational disease has entered a new stage ofdevelopment, with the implementation of the national health informatization project. To improve the efficiency and quality of occupational disease monitoring information reporting in this paper, the system architecture and related management regulations, as long as the major changes and achievement of "surveillance system of occupational disease and health hazards information" under the framework of National Health Insurance Informatization Project were elaborated. The deficiencies existing in the system were analyzed, and expectation for the construction of the occupational disease surveillance system was addressed.

[Exploration and practice of Peking University Model to improve the clinical teaching effect of clinical postgraduates majoring in periodontology].

The number of patients with periodontal disease in China is large, and the ratio of doctors to patients is seriously imbalanced, especially in the insufficient number of periodontal specialists and periodontal teachers. Strengthening the cultivation of professional postgraduates in periodontology can effectively solve this problem. This paper summarizes the experiences of Peking University School and Hospital of Stomatology in the teaching of periodontal postgraduate students for more than 30 years, in cluding teaching objectives formulation, teaching resources allocation and enhancement of the quality control system of clinical teaching, for ensuring that the periodontal professional postgraduates could reach the expected level after training. This formed the current "Peking University Model". There are both opportunities and challenges in clinical teaching of periodontal postgraduates in domestic stomatology community. The authors hope that the continuous exploration and improvement of this teaching system will promote the vigorous development of clinical teaching for the postgraduates majoring in periodontology in China.

[Application and research progress of autologous soft tissue substitute materials in gingival augmentation of natural teeth].

Subepithelial connective tissue or free gingival grafts are often used in traditional mucogingival surgery to treat gingival recession and keratinized gingival insufficiency. However, due to the disadvantages of autologous soft tissue grafts, such as the preparation of the second surgical site, the limited amount of tissue in the donor site, and postoperative discomfort for patients, the research on autologous soft tissue substitute materials has attracted extensive attention. A variety of donor-substitute materials from different sources are currently used in membranous gingival surgeries, including platelet-rich fibrin, acellular dermal matrix, xenogeneic collagen matrix, etc. This paper reviews the research progress and application of several different types of substitute materials in soft tissue augmentation for natural teeth, providing a reference for the application of autologous soft tissue substitutes in clinical gingival augmentation surgery.

[The histopathological characteristics of peri-implantitis].

Peri-implantitis (PI) has been defined as an inflammatory lesion of the mucosa surrounding an endosseous implant and with progressive loss of supporting peri-implant bones. In recent years, histopathological differences between PI and periodontitis of natural teeth had been described in animal experiments and a certain number of human experiments. In this paper, we review the histopathological differences between PI and periodontitis reported in the existing literature and try to find the differences in the occurrence and progression of these two diseases. Overall, inflammatory cell infiltrate (ICT) is more extensive in PI than in periodontitis, extending to the alveolar ridge, with dense infiltration of plasma cells, lymphocytes, macrophages, polymorphonuclear leukocytes and a greater number of osteoclasts in the connective tissue, but with less vascular density within ICT than in periodontitis. In addition, foreign bodies are found in PI lesions. The histopathological differences between the two diseases in terms of inflammatory infiltration, vascularity, bone loss, and foreign bodies could partially explain the more rapid progression of PI than periodontitis, suggesting that PI should be taken seriously by physicians. Early diagnosis and treatment are essential to control the progression of PI. In addition, targeted therapy against specific inflammatory cells may become a new direction for PI treatment; reducing titanium particles released into peri-implant tissue by friction or electrochemical corrosion may help to prevent PI.

[Profiles and differences of submucosal microbial in peri-implantitis and health implants: A cross-sectional study].

OBJECTIVE: To describe the submucosal microbial profiles of peri-implantitis and healthy implants, and to explore bacteria that might be correlated with clinical parameters. METHODS: In the present cross-sectional study, 49 patients were recruited. Each patient contributed with one implant, submucosal biofilms were collected from 20 healthy implants and 29 implants with peri-implantitis. DNA was extracted and bacterial 16S ribosomal RNA (16S rRNA) genes were amplified. Submucosal biofilms were analyzed using 16S rRNA sequencing at Illumina MiSeq platform. Differences between the groups were determined by analyzing α diversity, microbial component and microbial structure. The potential correlation between the bacteria with pocket probing depth (PPD) of peri-implant calculated by Spearman correlation analysis. RESULTS: The α diversity of submucosal microbial of health group was significantly lower than that in peri-implantitis group (Chao1 index: 236.85±66.13 vs. 150.54±57.43, P < 0.001; Shannon index: 3.42±0.48 vs. 3.02±0.65, P=0.032). Principal coordinated analysis showed that the submucosal microbial structure had significant difference between healthy and peri-implantitis groups [R2=0.243, P=0.001, analysis of similarities (ANOSIM)]. Compared with healthy implants, relative abundance of periodontal pathogens were higher in peri-implantitis, including members of the red complex (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola) and some members of orange complex (Precotella intermedia, Eubacterium nodatum, Parvimonas micra), as well as some new periodontal pathogens, such as Fillifactor alocis, Fretibacterium fastidiosum, Desulfobulbus sp._HMT_041, and Porphyromonas endodontalis. Spearman correlation analysis revealed that the relative abundance of Treponema denticola (r=0.686, P < 0.001), Tannerella forsythia (r=0.675, P < 0.001), Fretibacterium sp. (r=0.671, P < 0.001), Desulfobulbus sp._HMT_041 (r=0.664, P < 0.001), Filifactor alocis (r=0.642, P < 0.001), Fretibacterium fastidiosum (r=0.604, P < 0.001), Porphyromonas gingivalis (r=0.597, P < 0.001), Porphyromonas endodontalis (r=0.573, P < 0.001) were positive correlated with PPD. While the relative abundance of Rothia aeria (r=-0.615, P < 0.001) showed negatively correlation with PPD. CONCLUSION: Marked differences were observed in the microbial profiles of healthy implants and peri-implantitis. The members of red and orange complex as well as some new periodontal pathogens seem to play an important role in peri-implant disease. Compared with healthy implants, the submucosal microbial of peri-implantitis were characterized by high species richness and diversity.

[A case of intramuscular injection of methomyl poisoning].

Methomyl is a carbamate insecticide widely used in pesticides. Most of the poisoning methods are through digestive tract, respiratory tract and skin contact. At present, there is no report of poisoning caused by intramuscular injection. A case of poisoning caused by intramuscular injection of methomyl was analyzed retrospectively. About 4 minutes later, cholinergic crisis and central inhibition occurred. Venovenous-Extracorporeal Membrane Oxygenation (VV-ECMO) and atropine were given quickly. Finally, the patient was successfully rescued and had a good prognosis. After intramuscular injection of methomyl, cholinergic crisis can occur rapidly, and the onset rate is significantly faster than that of digestive tract, respiratory tract and skin contact.

[Healing of the dento-gingival junction following modified crown lengthening procedure in beagle dogs].

OBJECTIVE: To evaluate the type of wound healing following modified crown lengthening surgery in dog model to provide a biological basis for its clinical application. METHODS: Flap surgery, traditional crown lengthening procedure and modified crown lengthening procedure were performed on the right maxillary central incisor, the left maxillary central incisor and the left maxillary first lateral incisor respectively of five male beagle dogs. The right maxillary first lateral incisors with no surgical intervention were used as controls. Thirty-six weeks after the experimental procedure, tissue blocks were harvested and prepared for histological examination and analysis. RESULTS: Histometric examination of buccolingual sections stained with hematoxylin-eosin demonstrated that the type of wound healing in the flap surgery group was re-attachment, similar to the control group. For the traditional crown lengthening surgery group, all of the five beagle dogs had lamellar cementum defects on root surface, the wound healing of four beagle dogs was new attachment accompanied by new cementum formation at cementum defect areas and the suprac-restal connective tissue was functionally oriented perpendicular to the new cementum. The wound healing of the other beagle dog was long junctional epithelial attachment, in which the junctional epithelium extended to the apical terminus of the cementum defect. In the modified crown lengthening surgery group, four beagle dogs had cementum defects on root surface (two lamellar cementum defects and two shallow platform-like cementum defects), the wound healing of three beagle dogs was new attachment, however, the supracrestal connective tissue was parallel to the root surface. The type of wound healing of another one beagle dog was long junctional epithelial attachment. Wound healing of one beagle dog in this group could not be characterized due to incomplete dissection. CONCLUSION: Wound healing in the modified crown lengthening surgery group was similar to the traditional crown lengthening surgery group, and two types of wound healing were observed: new attachment and long junctional epithelium attachment. Neither type of root treatment procedure (root planing or root reshaping) nor root surface defect pattern (the lamellar cementum defect or shallow platform-like cementum defect) influenced the observed type of wound healing.

[Rethinking the marketing strategy of anti-tumor drugs by single-arm trials supported].

Single-arm trial refers to a clinical trial design that does not set up parallel control group, adopts open design, and does not involve randomization and blind method. These features, on the one hand, speed up the process of clinical trials, significantly shorten the time to market and meet the needs of patients with advanced malignancies, but also lead to the uncertainty of single-arm clinical trials themselves. Recently, the US Food and Drug Administration held a meeting of the oncologic drug advisory committee to discuss six tumor indications that have been accelerated approved, which once again triggered the discussion of single-arm trials. The basis of accelerated approval by single-arm trial is actually a compromise on the level of evidence-based medical evidence requirements after assessing the benefit risk. Therefore, the sponsor should strictly grasp the applicable conditions of single-arm trial in anti-tumor drugs and conduct single-arm trial scientifically. Post-marketing clinical trial should be implement as early as possible to ensure the benefit of patients. Based on the characteristics of single-arm trial, combined with two guidance relevant to single-arm trial issued by National Medical Products Administration recently, this article is supposed to propose and summarize the strategy of single-arm trial supporting the marketing of anti-tumor drugs.

[Efficacy of combined application of glycine powder air-polishing in non-surgical treatment of peri-implant diseases].

OBJECTIVE: To compare the clinical efficacy of combined application of glycine powder air-polishing and mechanical submucosal debridement in non-surgical treatment of peri-implant diseases. METHODS: A randomized controlled clinical study was carried out on patients diagnosed with peri-implant diseases in the Department of Periodontology, Peking University School and Hospital of Stomatology, between May of 2020 and June of 2021.Twenty-eight patients with totally sixty-two implants were enrolled.The patients were randomly divided into the test group and control group. The patients in the test group (13 subjects/32 implants) received mechanical submucosal debridement using titanium curettes combined with application of glycine powder air-polishing, while the control group (15 subjects/30 implants) received mechanical submucosal debridement using titanium only. Clinical parameters, such as plaque index (PLI), pocket probing depth (PPD), bleeding index (BI) and the percentage of suppuration on probing on implants' level (SoP%) were measured at baseline and 8 weeks after non-surgical intervention. Changes and group differences of clinical parameters of the implants before and 8 weeks after non-surgical intervention were compared. RESULTS: Mean PLI, PPD, BI of both the test group and control group significantly reduced 8 weeks after non-surgical intervention (P < 0.05). Compared with the control group, the test group achieved lower BI (2.7±0.8 vs. 2.2±0.7, P < 0.05), more reduction of BI (0.6±0.7 vs. 1.1±0.6, P < 0.01) and more reduction of SoP% (21.9% vs. 10%, P < 0.05) after non-surgical intervention. Both the control and test groups exhibited comparable PLI and PPD reductions (P>0.05). For the implants diagnosed with peri-implant mucositis, the test group revealed more signi-ficant reduction in BI and SoP% than the control group (1.0±0.7 vs. 0.4±0.7, P=0.02; 6.3% vs. 0, P=0.012). There was no significant difference existing in PLI and PD improvement between the control group and test group (P>0.05). For the implants diagnosed with peri-implantitis, there was no significant difference existing in PLI, PPD, BI and SoP% improvement values between the test and control groups (P>0.05). No complications or discomforts were reported during the study. CONCLUSION: Both treatment procedures could relieve the inflammation of peri-implant soft tissue. Non-surgical mechanical submucosal debridement combined application of glycine powder air-polishing is associated with significant reduction of soft tissue bleeding and suppuration on probing especially in the implants diagnosed with peri-implant mucositis.

[Clinical features and CT findings of Takayasu's arteritis associated pulmonary hypertension].

Objective: Takayasu's arteritis involving the pulmonary artery (PTA) is uncommon, and those with pulmonary hypertension (PH) are even rarer. This study investigated the clinical features and CT findings in PTA patients with PH. Methods: A total of 40 PTA patients were retrospective selected in the First Hospital of Air Force Medical University from January 2008 to January 2018. There were 14 PTA patients with PH, including 3 male and 11 female cases, aged from 18 to 53 (29.7±9.4) years, as the study group (PTA+PH group). There were 26 PTA patients without PH, including 4 males and 22 females, aged 15-52 (28.9±8.5) years, as the control group (PTA group). The Chi-square or Fisher's test, T test of two independent samples and Mann-Whitney U rank sum test were used to compare the general information, symptoms, signs, laboratory examination data, right ventricular and pulmonary artery measurement data, and pulmonary artery CT findings between the two groups. Results: Compared with the PTA group, the patients in the PTA+PH group had longer disease duration, fewer active cases, more shortness of breath, chest distress and lower limb edema, lower blood oxygen partial pressure (PaO2) and lower ESR (all P<0.05). The width of right atrium and right ventricle in PTA+PH group was greater than that in PTA group (all P<0.05). The main CT findings of the involved pulmonary artery included lumen stenosis (39 cases, 97.5%), lumen occlusion (16 cases, 40%), wall thickening (9 cases, 22.5%), and lumen dilation (2 cases, 5.0%). Patients in the PTA+PH group had less wall thickening and mild lumen stenosis (<50%), more severe lumen stenosis (≥50%) and occlusion than those in the PTA group (all P<0.05). Conclusions: PTA patients with PH showed certain characteristics in clinical, laboratory and CT findings, which may be correlated to the stage of the disease duration, the severity, and the prognosis.

[Exploration and practice of periodontal specialist training system].

The standardized training of specialist doctors is an important part of medical education after graduation and it is the only way to train clinicians to diagnose and treat the specialist diseases independently by using a standardized and high-quality way. The prevalence of periodontal disease and the proportion of patienets with severe and advanced periodontitis in our country are high and the diagnosis and treatment process for the periodontal disease are complicated. There is an urgent need to expand the team of periodontal specialists capable of the specialized treatment. The training of periodontal specialists in our country has just started. The present article summarizes the exploration and practice of periodontal specialist training in Peking University School and Hospital of Stomatology in the past five years, including the establishment of training bases, formulation of clear training goals, strict implementation of training rules, strengthening of process quality control to ensure the trainees could reach the expected standard of periodontal specialist after training. Through the summary of the previous stage practice, the authors hope to explore and establish a periodontal specialist training system in line with our country's national conditions and further to promote and accelerate the pace of nationwide periodontal specialist training system.

[Three-dimensional morphology analysis of the supraosseous gingival profile of periodontally healthy maxillary anterior teeth].

OBJECTIVE: To measure the three-dimensional morphology of the labial supraosseous gingiva (SOG) and the thickness of related labial bone in maxillary anterior teeth of periodontally healthy Han nationality youth using soft tissue indirect imaging cone-beam computed tomography (CBCT). METHODS: Twenty-five periodontally healthy subjects (11 males and 14 females) with 150 maxillary anterior teeth were involved in this study. A special impression with radiopaque material including the maxillary teeth was made, then a CBCT scan with the elastomeric matrix in position was taken for each subject. The imaging data were generated and transferred to a volumetric imaging software in which three-dimensional reconstruction was conducted and the image analyses were carried out. Measurements were made at the site of labial center of the maxillary anterior teeth. The height of the SOG, the distance between cemento-enamel junction (CEJ) and bone crest, the gingival thickness at the CEJ, and the thickness of bone 2 mm below the labial bone crest were measured and the correlation analysis between the parameters was made. All the data analyses were performed using SPSS 22.0. The data were analyzed with ANVOA and Pearson correlation tests with the significance level at α=0.05. RESULTS: The mean SOG values were (3.49±0.70) mm, (3.48±0.81) mm, and (3.54±0.67) mm for central incisors, lateral incisors and canines, respectively. There were no statistically significant differences among the different sites (P > 0.05). The mean gingival thickness values were (1.45±0.23) mm, (1.13±0.24) mm, (1.14±0.22) mm for central incisors, lateral incisors and canines, respectively. The gingival thickness of the central incisors was the largest among the maxillary anterior teeth with statistically significant difference (P < 0.05). No correlation was found between the SOG and gingival thickness among the maxillary anterior teeth (P > 0.05). CONCLUSION: The gingival thickness of central incisors was the largest and the supraosseous gingival height had no correlation with gingival thickness among the periodontally healthy maxillary anterior teeth.