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Effect of three mixing methods on air bubbles and solidification state of alginate impression materials ZHOU Yi-an, XIAO Song, XIE Xue-mei, WANG Yu-hua Shanghai Journal of Stomatology    2023, 32 (1): 12-16.   DOI: 10.19439/j.sjos.2023.01.003 Abstract （737）      PDF （658KB）（256）       Knowledge map    PURPOSE: To evaluate the effect of full-automatic mixing machine method, clockwise manual mixing and combined eight-shaped manual mixing on air bubble content, flowability, temperature, working time and setting time of alginate impression materials. METHODS: With the same condition, alginate impression materials were mixed by three different methods. The number of bubbles, area, flowability, temperature, working time and setting time were evaluated with SPSS 24.0 software package. RESULTS: The number of bubbles in the automatic mixing group was (2.30±2.50), and the area was (0.17±0.18) mm2, which was less than the number of clockwise manual mixing group (59.60±14.19), and the total area (7.41±2.24) mm2 (P<0.01). The flowability of the clockwise manual mixing group [(39.52±0.85) mm] was less than that of the full-automatic mixing group [(50.78±0.90) mm] and the combined eight-character manual mixing group [(50.36±1.75) mm](P<0.01).The setting time of the material mixed by three methods was eligible for clinical use. CONCLUSIONS: The mixing method of alginate impression material has an effect on material's bubble content, flowability and temperature changes. The impression materials mixed by full-automatic mixing method are better in terms of bubble content, flowability and other properties. If manual mixing is used, combined eight-shaped manual mixing method can help reduce impression bubbles and deformation, and improve flowability. Reference | Related Articles | Metrics

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Accuracy of tooth segmentation algorithm based on deep learning ZHANG Bo-jun, CUI Zhi-ming, LIU Zhi-xu, CHEN Si-yue, GU Kai-jun, LI Si-tong, WU Yan-qi, SHEN Ding-gang, ZHU Min Shanghai Journal of Stomatology    2024, 33 (4): 339-344.   DOI: 10.19439/j.sjos.2024.04.002 Abstract （686）      PDF （933KB）（338）       Knowledge map    PURPOSE: The established automatic AI tooth segmentation algorithm was used to achieve rapid and automatic tooth segmentation from CBCT images. The three-dimensional data obtained by oral scanning of real isolated teeth were used as the gold standard to verify the accuracy of the algorithm. METHODS: Thirty sets of CBCT data and corresponding 59 isolated teeth were collected from Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The three-dimensional tooth data in CBCT images were segmented by the algorithm. The digital information obtained by scanning the extracted teeth after processing was used as the gold standard. In order to compare the difference between the segmentation results and the scanning results of the algorithm. The Dice coefficient(Dice), sensitivity (Sen) and average symmetric surface distance (ASSD) were selected to evaluate the segmentation accuracy of the algorithm. The intra-class correlation coefficient(ICC) was used to evaluate the differences in length, area, and volume between the single tooth obtained by the AI system and the digital isolated tooth. Due to the existence of CBCT with different resolution, ANOVA was used to analyze the differences between groups with different resolution, and SNK method was used to compare them between two groups. SPSS 25.0 software package was used to analyze the data. RESULTS: After comparing the segmentation results with the in vitro dental scanning results, the average Dice value was (94.7±1.88)%, the average Sen was (95.8±2.02)%, and the average ASSD was (0.49±0.12) mm. By comparing the length, area and volume of a single tooth obtained by the digital isolated tooth and the AI system, the ICC values of the intra-group correlation coefficients were 0.734, 0.719 and 0.885, respectively. The single tooth divided by the AI system has a good consistency with the digital model in evaluating the length, area and volume, but the segmentation results were still different from the real situation in terms of specific values. The smaller the voxel of CBCT, the higher the resolution, the better the segmentation results. CONCLUSIONS: The CBCT tooth segmentation algorithm established in this study can accurately achieve the tooth segmentation of the whole dentition in CBCT at all resolutions. The improvement of CBCT resolution ratio can make the algorithm more accurate. Compared with the current segmentation algorithms, our algorithm has better performance. Compared with the real situation, there are still some differences, and the algorithm needs to be further improved and verified. Reference | Related Articles | Metrics

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Short-term efficacy of three root canal filling methods in endodontic treatment of chronic periapical inflammation GUO Jing-jing, TANG Yi-qun, HE Hong, XU Zhen Shanghai Journal of Stomatology    2022, 31 (5): 544-549.   DOI: 10.19439/j.sjos.2022.05.018 Abstract （617）      PDF （684KB）（504）       Knowledge map    PURPOSE: To provide a reference basis for clinical selection of a reasonable and effective root canal treatment by comparing the short-term clinical efficacy of three root canal filling methods in the treatment of chronic periapical inflammation. METHODS: One hundred and twenty patients with chronic periapical inflammation who received root canal filling between October 2019 and October 2020 were randomly divided into 3 groups, with 40 patients in each group. All patients received root canal filling, group A was filled with iRoot SP paste by matched-taper single cone obturation technique, group B was filled with AH-plus paste by warm vertical condensation, and group C filled with AH-plus paste by cold lateral condensation. Root canal filling time in the three groups was calculated, pain score 24 h after treatment was determined using visual analogue scale/score(VAS), and periapical index(PAI) was used to evaluate radiographs. SPSS 22.0 statistical software was applied for data analysis. RESULTS： Root canal filling times in the three groups were (75.50±7.44) s in group A, (85.38±3.46) s in group B and (102.33±3.32) s in group C, the differences were statistically significant (P<0.05); the incidence of postoperative pain in the three groups was 25% in group A, 25% in group B and 32.5% in group C, the difference was not statistically significant(P>0.05). There was no significant difference between group A and group B, but significant difference existed between group A, group B and group C. The results of comparison of PAI scores showed a time effect was F=498.93, P<0.001, suggesting significant difference in total PAI scores at different time points; a group effect was F=0.91, P=0.406, suggesting no significant difference in total PAI scores of the 3 groups; an interaction effect of time and group was F=0.44, P=0.777, suggesting that there was no significant difference in total PAI scores of the 3 groups at the time points. The total effective rate at 3 and 12 months was 97.5%, 97.3% in group A, 97.5%, 97.2% in group B and 90%, 91.9% in group C, the difference was not statistically significant(P>0.05). CONCLUSIONS: Compared with the other 2 root canal filling methods, the iROOT SP paste matched-taper single cone obturation technique is clinically effective in terms of time saving and increasing the comfort of the patients' visit. Reference | Related Articles | Metrics

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Applied anatomy of the stylomastoid foramina and its relation to the surrounding bone structures QIN Si-jia, LIU Huan-qi, ZHANG Yu-qing, WANG Dan-yang, HUANG Shuo, WANG Feng, LIU Chang-kui Shanghai Journal of Stomatology    2023, 32 (6): 568-571.   DOI: 10.19439/j.sjos.2023.06.002 Abstract （617）      PDF （607KB）（216）       Knowledge map    PURPOSE: To study the relationship between the stylomastoid foramen and surrounding bony structures, enrich anatomical data and provide reference for clinical surgery. METHODS: A total of 62 intact and dry adult skulls were selected. The shape of the stylomastoid foramen was observed, the diameter of the stylomastoid foramen, the distances from the posterolateral point and the anterior medial point to the surrounding bony structures were measured with a vernier caliper. SPSS 25.0 software package was used to analyze the data. RESULTS: There were four shapes of stylomastoid foramen, i.e., circular (61.29%), oval (29.84%), irregular (8.06%) and triangular (0.81%). The circular diameter was (2.80±0.61) mm, the oval long and short diameters were (4.43±0.96) and (2.79±0.60) mm. Distances from the posterolateral and anterior medial points of the stylomastoid foramen to the posterolateral point of the external opening of the carotid canal, the anterior medial point of the jugular foramen, the midline, the most anterior point of the foramen magnum, the posterior point of the great palatine foramen, the posterolateral point of the foramen lacerated, the foramen ovale, the posterolateral point of the foramen spinosum, the anterior point of the styloid process root, the outermost point of the tympanomastoid fissure and the tip of the mastoid process were (16.10±2.81), (24.01±2.65), (44.95±3.24), (45.10±2.71), (61.66±4.14), (35.56±4.35), (32.26±2.85), (29.12±3.40), (10.39±3.25), (9.49±2.24) and (12.01±2.79) mm; (12.80±2.41), (21.56±2.51), (42.96±3.97), (42.91±2.76), (58.97±3.97), (32.98±4.14), (29.20±2.77), (25.80±2.87), (7.37±2.33), (11.42±2.00) and (15.41±2.57) mm, respectively. Statistical analysis showed that there was no significant difference in the apertures and distances between the left and right side(P>0.05). CONCLUSIONS: Most of the stylomastoid foramen are round and oval, understanding the distance between the foramen and surrounding bony structures is helpful for guiding clinical operations and enriching anatomical knowledge. Reference | Related Articles | Metrics

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A reflectional insight into orthodontic theoretical renovation and technological innovation SHEN Gang Shanghai Journal of Stomatology    2023, 32 (2): 113-119.   DOI: 10.19439/j.sjos.2023.02.001 Abstract （606）      PDF （867KB）（572）       Knowledge map    Orthodontics, among other specialties in dentistry, remains most dynamic and vigorous in upgrading and reforming its fundamental doctrines and clinical technologies. Orthodontic specialty in China has played a leading role in recent years in reshaping fundamental theories and in creating cutting-edge therapeutic modalities. The newly developed diagnostic classification system, a complementary addition to that of Angle's, not only defines the natures, but also identifies the developmental mechanisms of malocclusions. Orthopedic therapy aiming to relocate the mandible before correcting the dentition is emerging as an indispensable treatment mode to malocclusions concurring with mandibular deviation. Whilst correlations exist between malocclusion and TMD susceptibility and incidence, the specifically designed orthopedic and orthodontic approaches have proven effective in managing cases inflicted by TMD conditions. Innovative efforts that create the GS products, have redefined the clear appliances much more beyond merely clear aligners, thus further pushing the boundaries of both the indications and clinical use for clear appliances. Reference | Related Articles | Metrics

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Segmentation, accuracy validation of mandibular molar, pulp cavity on cone-beam CT images by U-net neural network LIN Xiang, FU Yu-jie, REN Gen-qiang, WEN Jia-huan, CHEN Yu-fei, ZHANG Qi Shanghai Journal of Stomatology    2022, 31 (5): 454-459.   DOI: 10.19439/j.sjos.2022.05.002 Abstract （599）      PDF （912KB）（531）       Knowledge map    PURPOSE: To realize the automatic segmentation of mandibular molar and pulp cavity on cone-beam CT (CBCT) images by U-net convolutional neural network, and to use the 3D models reconstructed by Micro-CT data as the ground truth to validate its accuracy. METHODS: Twenty groups of small field of view(FOV) CBCT data containing complete mandibular molars were collected from the Department of Radiology, Affiliated Stomatology Hospital of Tongji University. After preprocessing, an endodontic specialist labeled teeth and pulp cavities by MITK Workbench software. These data were used as the training set for training U-net neural network. In addition, five mandibular molars and corresponding small FOV CBCT data were collected. These five CBCT were processed in the same way and used as the testing set. Then, teeth and pulp cavities on CBCT images of the testing set were segmented and reconstructed by U-net neural network and the same specialist. The isolated teeth were scanned by a Micro-CT machine after preprocessing and the results were reconstructed to 3D models, which were used as the ground truth. Then the 3D models reconstructed by the specialist’s labeling, U-net network segmentation results, and the ground truth in the testing set were compared. Dice similarity coefficient(DSC), average symmetric surface distance (ASSD), Hausdorff distance (HD), and morphological analysis were used to evaluate the results. SPSS 20.0 software package was used for statistical analysis. RESULTS: Compared with the ground truth, the segmentation accuracy of the U-net neural network measured by DSC, ASSD, and AHD was (95.30±1.01)%, (0.11±0.02) mm, and (1.05±0.31) mm in teeth and (81.21±2.27)%, (0.15±0.05) mm, and (3.29±1.85) mm in the pulp cavity, respectively. Morphological analysis results showed that the U-net network segmentation results were similar to the ground truth in tooth and pulp chamber. As for the segmentation results of root canals, only thick root canals could be segmented rather than the thin root canals, such as the canals in the apical third and lateral root canals. CONCLUSIONS: Under the experimental conditions, the U-net neural network trained by the specialist’s labeling realized the automatic and accurate segmentation of mandibular molar and their pulp chamber on CBCT images. For the segmentation of root canals, the results need to be further improved. Reference | Related Articles | Metrics

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A novel periodontal endoscopy-aided non-incisional periodontal regeneration technique：a case series study SHI Jia-hong, LI Jing-wen, JIANG Li-shan, LEI Lang, LI Hou-xuan Shanghai Journal of Stomatology    2024, 33 (1): 80-84.   DOI: 10.19439/j.sjos.2024.01.014 Abstract （596）      PDF （888KB）（298）       Knowledge map    PURPOSE: To investigate the effect of endoscopy-aided non-incisional periodontal regeneration technique (NIT) in the treatment of alveolar bone angular resorption. METHODS: Thirteen patients with severe periodontitis(13 diseased teeth) were selected. All patients had alveolar bone angular resorption on adjacent surface. The patients received NIT treatment 6 weeks after periodontal primary therapy. The visualization of subgingival environment was acquired by the periodontal endoscopy. Following the removal of the subgingival plaque, calculus and intra-bony granulation tissue, bone grafting materials were placed into the intra-bony defects with the assistance of a delicate gingival protector. No flap was elevated and no sutures were applied. Probing depth (PD), gingival recession (GR), clinical attachment level (CAL), as well as radiographic parameters were evaluated at baseline and 2 years after treatment. SPSS 22.0 software package was used for data analysis. RESULTS: At 2-years follow-up, an average CAL gain of (3.65±2.10) mm (P<0.001), PD reduction of (4.42±1.66) mm (P<0.001), and minimal increase in GR of (0.38±0.87) mm (P=0.25) were observed. Alveolar bone was significantly improved at 2-years follow-up on radiographs (P<0.001). CONCLUSIONS: For angular resorption site of alveolar bone, NIT treatment can obtain good periodontal regeneration results without flap inversion. Reference | Related Articles | Metrics

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TNF-α regulated SHED osteogenic differentiation through ERK1/2-Runx2 signaling pathway WANG Jing, XU Na, REN Hui-di Shanghai Journal of Stomatology    2024, 33 (2): 135-140.   DOI: 10.19439/j.sjos.2024.02.005 Abstract （590）      PDF （1435KB）（163）       Knowledge map    PURPOSE: To investigate the effect of TNF-α on osteogenic differentiation of stem cells from human exfoliated deciduous teeth (SHED), and to analyze the changes of ERK1/2-Runx2 signaling pathway in the regulation process. METHODS: SHED cells were isolated and cultured from normal deciduous permanent teeth of healthy children aged 6-8 years old, and the third passage of SHED cells were taken and divided into control group (osteogenic inducer culture), observation group (osteogenic inducer and TNF-α co-culture) and agonist group (osteogenic inducer, TNF-α and ERK pathway agonist co-culture). The osteogenic differentiation was determined by alizarin red staining. The protein expression levels of Osterix, OPN, ERK1/2, pERK1/2 and Runx2 in SHED cells were determined by Western blot. The expressions of Osterix, OPN, ERK1/2, pERK1/2 and Runx2 mRNA were detected by qRT-PCR. Statistical analysis was performed with SPSS 26.0 software package. RESULTS: Comparison of osteogenic differentiation ability of the three groups of cells showed that red-brown mineralized nodules were observed in the three groups of cells. Compared among the three groups, the control group had the most mineralized nodules, followed by the activation group, and the observation group had the least mineralized nodules. Compared with the control group, the expression levels of Osterix and OPN protein and mRNA in the observation group and the agonist group were significantly decreased, while the expression levels of Osterix and OPN protein and mRNA in the agonist group were significantly higher than those in the observation group. There was no significant difference in the expression levels of ERK1/2 protein and mRNA among the three groups, while the expression levels of pERK1/2 and Runx2 protein and mRNA in the observation group and the agonist group were significantly higher than those in the control group, and the expression levels of pERK1/2 and Runx2 protein and mRNA in the agonist group were significantly higher than those in the observation group. CONCLUSIONS: TNF-α can inhibit osteogenic differentiation of SHED cells, which may be related to the inhibition of ERK1/2-Runx2 signaling pathway. Reference | Related Articles | Metrics

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Effect of collagen sponge on the healing process of alveolar fossa after tooth extraction in rats LI Jun-fu, ZHU Jia, JIANG Juan, WANG Xu-xia, CHEN Dai-yun, ZHAO Zuo-qin Shanghai Journal of Stomatology    2023, 32 (3): 241-245.   DOI: 10.19439/j.sjos.2023.03.004 Abstract （560）      PDF （759KB）（326）       Knowledge map    PURPOSE: To investigate the effect of collagen sponge on early bone healing process of alveolar fossa after tooth extraction in rats. METHODS: A total of 16 healthy female SD rats were selected. Animal models with tooth extraction were established. The right alveolar fossa inserted with collagen sponge was as the experimental group, and the left alveolar fossa was as the control group with treatment. The rats were sacrificed 1, 2, 4 and 8 weeks after tooth extraction, and the osteogenesis of alveolar fossa was observed. Real-time quantitative PCR (qt-PCR) was used to detect the changes of osteogenesis related gene expression. SPSS 19.0 software package was used for statistical analysis. RESULTS: After surgery, alveolar cavity healing was significantly better in the experimental group than in the control group. Osterix, Runx2 and Vegf genes were expressed in the experimental group and the control group, and the expression levels of related genes in the experimental group were significantly higher than the control group 1, 2, 4 and 8 weeks after surgery(P<0.05). CONCLUSIONS: Collagen sponge could promote early alveolar bone healing, possibly related to the expression level of osteogenic genes regulated by collagen sponge. Reference | Related Articles | Metrics

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Review of clinical effects of disk-up sinus reamer(DSR)-based internal sinus floor elevation with implantation in 10 years ZHANG Kai-yue, HAN Ze-yu, JIANG Shuai, XU Hao, LI Fan, ZHAO Bao-dong Shanghai Journal of Stomatology    2024, 33 (1): 64-70.   DOI: 10.19439/j.sjos.2024.01.011 Abstract （512）      PDF （1101KB）（282）       Knowledge map    PURPOSE: To analyze the bone remodeling around the implant 10 years after disk-up sinus reamer(DSR)-based internal sinus floor elevation with implantation and to investigate the influence of different factors on implant retention. METHODS: The clinical and imaging data of patients undergoing DSR-based sinus floor elevation with simultaneous implantation were collected from the Department of Dental Implantology, Affiliated Hospital of Qingdao University from January 2008 to December 2011. Panoramic film and CBCT were used to measure the changes of bone mass around implant in different periods. Kaplan-Meier and Log-rank tests were used to analyze the effects of different factors on implant retention with SPSS 26.0 software package. RESULTS: The study included 98 patients with a total of 128 implants. During the follow-up of 0-168 months, 7 implants failed, and the remaining formed good osseointegration and functioned, with a 10-year cumulative retention rate of 94.53%. The height of bone formation was (0.29±0.15) mm at the top and (2.74±0.66) mm in the sinus of 75 implant sites with complete imaging data obtained ten years after surgery. Kaplan-Meier and Log-rank tests showed that 8 factors including initial bone height, elevated bone height, mucosal perforation, implant length, implant torsion, diabetes, smoking and periodontitis had significant effects on implant retention. CONCLUSIONS: The DSR-based internal sinus floor elevation with implantation is a reliable and stable bone augmentation operation for vertical bone defect in maxillary posterior region, with a 10-year cumulative retention rate of no less than 94%. Initial bone height, elevated bone height, mucosal perforation, implant length, implant torsion, diabetes, smoking and periodontitis are the important factors affecting the long-term retention rate of implants. Reference | Related Articles | Metrics

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Comparative analysis of the effect of autologous dentin particles, implantation of Bio-Oss on guided bone regeneration in the treatment of periodontal bone defects MAO Xin-xia, LIN Xiao-wei, WEI Xuan, LI Qin Shanghai Journal of Stomatology    2022, 31 (5): 530-534.   DOI: 10.19439/j.sjos.2022.05.015 Abstract （510）      PDF （597KB）（450）       Knowledge map    PURPOSE: To analyze the effect of autologous dentin particles and Bio-Oss bone powder implantation on guided bone regeneration in the treatment of periodontal bone defects. METHODS: Eighty-two patients with periodontal bone defect treated in Zhangye People's Hospital from May 2018 to May 2020 who underwent guided bone regeneration treatment were selected and divided into experimental group and control group according to random number table method, with 41 cases in each group. The control group was implanted with Bio-Oss during the operation, and the experimental group was implanted with autologous dentin particles during operation. Periodontal pocket depth and attachment loss, buccal soft tissue profile, buccal soft tissue thickness, red aesthetic score, success rate, and complications were compared between the two groups of patients. SPSS 22.0 software package was used for statistical analysis. RESULTS: Comparison within the group showed that 1 month and 1 year after operation, the periodontal pocket depth and attachment loss of the two groups were significantly reduced(P<0.05); and 1 year after operation, the periodontal pocket depth and attachment loss of the two groups were significantly lower than 1 month after surgery(P<0.05). Comparison between groups showed that 1 month and 1 year after operation, the periodontal pocket depth and attachment loss of the experimental group were significantly lower than those of the control group (P<0.05). Comparison within groups showed that 1 month and 1 year after operation, the buccal soft tissue profile of the two groups were significantly higher than that before operation (P<0.05); and 1 year after operation, the buccal soft tissue profile of the two groups were significantly lower than 1 month after operation. Comparison between groups showed that 1 year after operation, the buccal soft tissue profile of the experimental group was significantly higher than that of the control group (P<0.05). Comparison within groups showed that 1 month and 1 year after surgery, the thickness of the buccal soft tissue of the two groups were significantly higher than that before surgery. Comparison between groups showed that there was no significant difference in the thickness of the buccal soft tissue at each time point between the two groups(P>0.05). Comparison within groups showed that 1 month and 1 year after operation, the red aesthetic scores of patients in the two groups were significantly higher than those before operation (P<0.05); in addition, the red aesthetic scores of the two groups 1 year after surgery were significantly higher than those 1 month after surgery (P<0.05). Comparison between groups showed that 1 month and 1 year after surgery, the red aesthetic scores of the experimental group were significantly higher than those of the control group (P<0.05). One year after operation, the success rate of the experimental group and the control group were 90.24% (37/41) and 85.37% (35/41), respectively, and there was no significant difference between the two groups(P>0.05). There was no significant difference in the incidence of complications between the two groups(P>0.05). CONCLUSIONS: Autologous dentin particles can be used to guide bone regeneration to treat patients with periodontal bone defects, which can reduce the depth of periodontal pockets and loss of attachment, improve the buccal soft tissue profile and red aesthetic score, and the success rate is equivalent to implantation of Bio-Oss. Therefore, it is a safe and reliable treatment method. Reference | Related Articles | Metrics

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Application of 3D printing modified tooth-supported cyst plug in decompression of mandibular cystic lesions KOU Peng, LI Ying-mei, LI Zhi-ping, MENG Jian Shanghai Journal of Stomatology    2023, 32 (2): 203-208.   DOI: 10.19439/j.sjos.2023.02.017 Abstract （497）      PDF （1849KB）（505）       Knowledge map    PURPOSE: To evaluate the application value of 3D printing modified dental support cyst plug in fenestration of large jaw cystic lesions. METHODS: Forty patients with mandibular cystic disease in Xuzhou Central Hospital from October 2019 to April 2021 were selected. They were randomly divided into experimental group(3D printing group) and control group (traditional plug group), with 20 cases in each group. All enrolled patients underwent preoperative digital modeling of cystic lesions of the jaw, obtained the cystic cavity volume data of preoperative lesions, designed the windowing site according to the plan and performed decompression for jaw cysts. Three days after surgery, the patient's postoperative CBCT and Oral-scan data in the experimental group was obtained, and a digitally modified tooth-supported cyst plug with porous column channel was designed, and titanium alloy material for 3D printing was selected. In the control group, the plug was manually molded by experienced physicians. The visual analogue scale(VAS) score of pain, retention, mechanical properties of the plug and its effect on the adjacent teeth were compared between the two groups during the process of model preparation, and the changes of the cyst volume 1, 3 and 6 months after operation were compared between the two groups. SPSS 25.0 software package was used for data analysis. RESULTS: Compared with the control group, the patients in the experimental group who made titanium alloy as printing material by digital impression complained more comfortable, and the mechanical strength and stability of the cyst plug were better than those in the control group(P< 0.05). There was no significant difference in retention between the two groups(P>0.05). The reduction rate of cyst volume in the experimental group was significantly higher than that in the traditional plug group 3 and 6 months after operation(P<0.05). CONCLUSIONS: The modified tooth-supported titanium alloy cyst plug with digital 3D printing has good mechanical properties and stability. It has little damage to the abutment and no lateral force, and has the advantages of precision, individualization and comfort. The improved irrigation and injection channel can fully flush the cavity and speed up the narrowing of the cyst and reduce the waiting time before the second operation, which is worth promoting in clinical practice. Reference | Related Articles | Metrics

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An in vitro experiment on the stability and irritant of hypochlorous acid in oral cavity LIU Zhao-chen, SUN Pei, PAN Ke-qing, WANG Pei-yan, ZHANG Hui, YUAN Chang-qing, DENG Jing Shanghai Journal of Stomatology    2024, 33 (2): 141-147.   DOI: 10.19439/j.sjos.2024.02.006 Abstract （492）      PDF （2020KB）（331）       Knowledge map    PURPOSE: To study the stability of physicochemical properties and sterilizing effect about two commercially available hypochlorous acid (HClO) products under simulated clinical conditions, and to evaluate the compatibility of HClO on soft and hard tissues and cells in oral cavity. METHODS: Samples of HClO solution with different production processes were prepared, to detect the changes of physicochemical indexes of each sample over time under simulated clinical conditions (shielded from light at 20-25 ℃, open the cover for 5 minutes every day), including free available chlorine, oxidation-reduction potential and pH. Through suspension quantitative germicidal test, the antibiosis-concentration curve of HClO solution was made, so as to calibrate the change of antibacterial ability of disinfectant with the decrease of available chlorine content during storage. Pulp, tongue and dentine were immersed in PBS, 100 ppm HClO, 200 ppm HClO and 3% NaClO. The influence on soft and hard tissues was evaluated by weighing method and microhardness test. The toxic effects of HClO, NaClO and their 10-fold diluent on human gingival fibroblasts were determined by CCK-8 cytotoxicity assay. GraphPad PRIS 8.0 software was used to analyze the data. RESULTS: Under simulated conditions, the free available chlorine (FAC) of HClO solution decayed with time, and the attenuation degree was less than 20 ppm within 1 month. The bactericidal effect of each HClO sample was still higher than 5log after concentration decay. There was no obvious dissolution and destruction to soft and hard tissues for HClO(P>0.05). The cell viability of HClO to human gingival fibroblast cells (HGFC) was greater than 80%, which was much higher than 3% NaClO (P<0.001). CONCLUSIONS: The bactericidal effect and stability of HClO solution can meet clinical needs, which has low cytotoxicity and good histocompatibility. It is expected to become a safe and efficient disinfection product in the field of living pulp preservation and dental pulp regeneration. Reference | Related Articles | Metrics

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Evaluation of the 5-year clinical restoration effect of implants retained complete overdentures with Locator attachments in 48 patients ZHOU Tuan-feng, YANG Xue, ZHANG Hua, ZHANG Zhi-yong, CHEN Quan Shanghai Journal of Stomatology    2024, 33 (1): 90-96.   DOI: 10.19439/j.sjos.2024.01.016 Abstract （482）      PDF （998KB）（218）       Knowledge map    PURPOSE: To observe the long-term clinical effect of implants retained complete overdentures with Locator attachments. METHODS: A total of 48 patients with edentulous jaws treated with implants retained complete overdentures with Locator attachments were selected from the Outpatient Department of Peking University School and Hospital of Stomatology from 2016 to 2017. Among them, 21 patients underwent double-maxillary complete overdentures restoration and 27 patients underwent single-maxillary restoration. A total of 230 implants were implanted. The clinical observation indicators included the implant survival rate, peri-implant mucosal bleeding on probing(BOP), the change in the vertical height of alveolar bone absorption around the implants, overdenture base fracture rate, artificial tooth fall off and fracture rate and other complications. The change of the locator attachment retention force of the implant-supported overdentures was evaluated. SPSS 13.0 software package was used for data analysis. RESULTS: During the five-years clinical observation period, 5 implants fell off, 1 narrow dimeter implant in the anterior zone was broken, and 12 implants were lost to follow-up. The implant survival rate was 97.25%. One year after the restoration therapy finished, peri-implant mucosal bleeding on probing (BOP+) was detected in 48 (21.4%) implants. The average BI was 0.21±0.42, which was higher in the anterior zone than that in the posterior zone. The vertical alveolar bone absorption height around the implants was (0.21±0.35) mm, 2 implants-supported complete overdenture bases were broken. After 5 years of restoration, 163(76.89%) implants had peri-implant mucosal bleeding on probing(BOP+). The average BI was 1.00±0.70, and the vertical alveolar bone absorption height around the implants was (0.58±0.85) mm. There was no significant difference between males and females. There was no significant difference in the peri-implant mucosal bleeding index and the alveolar bone vertical absorption height between the anterior zone and the posterior zone(P>0.05). The mean BI of peri-implant mucosa and the vertical absorption height of peri-implant alveolar bone were significantly different between the 1-year observation period and the 5-year observation period respectively(P<0.01). There were 17(26.15%) cases with overdenture bases fracture, and the fracture rate of artificial teeth was 16.92%. Most of them occurred in the midline area of the anterior zone and the location of the overdenture base on the locator attachments. The average first replacement time of the locator attachment nylon retainer washer was 34.2±10.3 months. CONCLUSIONS: Implants retained complete overdentures with Locator attachments are effective in long term clinical observation. Complications are mainly found in peri-implant mucosal bleeding on probing and vertical alveolar bone absorption, and tended to increase gradually over time. The fracture of the implant retains complete overdenture bases and the fall off or fracture of the artificial teeth are the second serious complications. Overdenture base with metal frame at the location of the Locator abutment and the midline of the anterior area should be strengthened, and narrow diameter implants should be avoided as far as possible in the anterior zone. Reference | Related Articles | Metrics

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Effectiveness of adjunctive photodynamic therapy in the treatment of stage Ⅲ, Ⅳ periodontitis FAN Ya-dan, SHU Rong, CHENG Lan, GE Lin-hua Shanghai Journal of Stomatology    2022, 31 (5): 501-506.   DOI: 10.19439/j.sjos.2022.05.010 Abstract （479）      PDF （583KB）（374）       Knowledge map    PURPOSE: To explore the clinical effect of subgingival scaling and root planning (SRP) with adjunctive photodynamic therapy (PDT) in the treatment of stage Ⅲ and Ⅳ periodontitis. METHODS: According to 2018 Classification of Periodontitis, patients diagnosed as stage Ⅲ and Ⅳ periodontitis were recruited. One week after supragingival scaling, probing depth (PD), bleeding on probing (BOP) and gingival index (GI) were recorded as the baseline. All patients were divided into 3 groups, SRP group received whole mouth SRP treatment; PDT1 group: PDT at all sites with PD≥5 mm immediately after SRP; PDT2 group received another PDT at the test sites 6 weeks after full mouth SRP+PDT. PD, GI and the positive rates of BOP were compared 3 months and 6 months after treatment. SPSS 22.0 software package was used for data analysis. RESULTS: Thirty patients and 1 289 test sites were included in this trial. There were 10 patients in group SRP, PDT1 and PDT2, and the number of tests sites were 476, 36.9%, 384, 29.8% and 429 33.3%, respectively. The PD, GI and the positive rates of BOP in the three groups were reduced at 3-months and 6-months of follow-up (P<0.05), there was no significant difference between 3-months and 6-months of follow-up. At the site of PD≥5 mm, group PDT1 and PDT2 could significantly reduce GI and the positive rates of BOP at the test sites(P<0.05). When PD≥7 mm, significant PD reduction was observed in group PDT2(P<0.05). CONCLUSIONS: In the treatment of stage Ⅲ and Ⅳ periodontitis, PDT assisted with SRP therapy can achieve better clinical effect than SRP alone. Reference | Related Articles | Metrics

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Experimental study of the gap ossification in the double-barrel technique in rabbit tibia WANG Xiao-lin, SU Ming, LI De-long, HAN Zheng-xue Shanghai Journal of Stomatology    2022, 31 (5): 497-500.   DOI: 10.19439/j.sjos.2022.05.009 Abstract （474）      PDF （1099KB）（207）       Knowledge map    PURPOSE: Double-barrel vascularized fibula graft is one of the most common surgical techniques to augment or maintain the height of the neo-mandible. The purpose of this study was to investigate whether the gap completely disappeared and gap ossification ultimately achieved between the double barrels. METHODS: Six rabbits were used in the study. Each animal's tibia was vertically osteotomized at its midpoint, folded onto each other and fixed by mini-titanium plate, thus an animal model of “double barrel” was established. Specimens were obtained at 3 months and 6 months postoperatively, then the gap ossification between the double barrels was evaluated by radiography and histomorphology. Measurements of the gap width between the two tibial struts on X-ray films were performed 3 months after the operation at three sites: distal, middle and proximal site. Measurements were compared with those obtained immediately after operation using SPSS 19.0 software package. RESULTS: Three months after operation, radiography demonstrated that the gap between the double barrels gradually became vague. Histological study showed that irregular new woven bone formed in the gap between the two struts. There was significant difference in mean gap width at the distal and proximal site (P<0.05), but there was no significant difference at the middle site(P=0.552). Radiological and histological study showed cortical bone resorption in the contact area and two thin tubular bones fused into a thicker one 6 months postoperatively. CONCLUSIONS: The double-barrel tibia fixed with titanium microplate can fuse into a large, unique, continuous bone barrel. Reference | Related Articles | Metrics

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Imaging findings of carcinoma ex pleomorphic adenoma in minor salivary glands ZHU Wen-Jing, YU Qiang, TAO Xiao-feng, WANG Shao-ying, TIAN Tao, ZHANG Chun-ye Shanghai Journal of Stomatology    2023, 32 (3): 255-260.   DOI: 10.19439/j.sjos.2023.03.007 Abstract （470）      PDF （1392KB）（251）       Knowledge map    PURPOSE: To summarize the CT and MR imaging features of carcinoma ex pleomorphic adenoma(Ca-ex-PA) in minor salivary gland, and analyze the correlation between various features and pathological classification. METHODS: Forty-three patients with Ca-ex-PA in minor salivary gland were collected. The CT and MRI findings were retrospectively analyzed and correlated with their pathological types. Fisher's exact test was used to analyze the correlation between various imaging features (tumor morphology, boundary, internal structure, bone invasion, cervical lymph node metastasis) and pathological types with SPSS 25.0 software package. RESULTS: Among the 43 patients with Ca-ex-PA, 83.7%(36/43) of the tumors were lobulated; 81.4%(35/43) showed cystic degeneration or necrosis, with heterogeneous enhancement. Coarse calcification or mixed calcification was found in 37.2%(16/43), 25.6%(11/43) had compressive absorption of adjacent bone. 75%(12/16) of type Ⅰ/Ⅱ tumors had regular morphology (round or oval), and 77.8%(21/27) of type Ⅲ tumors had irregular morphology, 93.8%(15/16) of type Ⅰ/Ⅱ tumors had well-defined margin and 66.7%(18/27) of type Ⅲ tumors had ill-defined margin. Osteolytic bone resorption occurred in 59.3%(16/27) of type Ⅲ tumors. The average maximum diameter of type Ⅰ/Ⅱ tumors was significantly shorter than that of type Ⅲ(P<0.05). Fisher's exact test showed the characteristics of tumor morphology, boundary and osteolytic bone resorption were related to pathological grouping(P<0.001). CONCLUSIONS: Most Ca-ex-PA in minor salivary glands is characterized by lobular and heterogeneous enhanced neoplasm on CT and MR imaging. A round or oval tumor with well-defined margin usually correlates with typeⅠ and Ⅱ, contrarily, an irregular mass with ill-defined margin and osteolytic bone destruction usually correlates with type Ⅲ. Combining the three characteristics of morphology, boundary and osteolysis is more helpful to distinguish type Ⅰ/Ⅱ and type Ⅲ tumors. Reference | Related Articles | Metrics

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Experimental study on the optical properties of different-translucency zirconia-ceramic restorations ZOU Yan, XIONG Pei-wen, ZHU Hong-shui Shanghai Journal of Stomatology    2023, 32 (2): 154-157.   DOI: 10.19439/j.sjos.2023.02.008 Abstract （469）      PDF （524KB）（246）       Knowledge map    PURPOSE: The purpose of this in vitro study was to measure the color difference(△E) on titanium alloy background and translucency parameter(TP) of four kinds of zirconia-based all-ceramic specimens, providing a clinical reference for restoring grayish abutment. METHODS: Four groups with a total of 24 ceramic specimens were fabricated to a final specimen dimension of 14 mm×14 mm×1.5 mm, two kinds of zirconia with different translucency（Beitefu high-translucency, Cercon low-translucency）and their corresponding body porcelain at the shade of A2 were used as followed:high-translucency zirconia sintered dentine porcelain(Group A),low-translucency zirconia sintered dentine porcelain(Group B),high-translucency zirconia sintered opaque and dentine porcelain(Group C),low-translucency zirconia sintered opaque and dentine porcelain(Group D).The color parameters of the specimens under two backgrounds (titanium alloy and shade A3 light-activated resin-based composite) were measured by Shade Eye NCC colorimeter, then the △E value was determined by the relevant equations. The color parameters under black and white background were measured, and TP value was calculated. The experimental data were analyzed with SPSS 17.0 software package. RESULTS: There was significant difference of the TP value and the △E value among four groups specimens(P<0.05), the TP value was arranged as follows: group D<group C<group B<group A. The specimen used with opaque porcelain showed significantly reduced translucency. The △E value was arranged as follows :group D < group C < group B < 1.5 < 2 <group A, the △E value of group A cannot be accepted in clinic. CONCLUSIONS: The restoration of low-translucency zirconia sintered translucency veneering ceramic has better translucency, with value of △E<1.5 when used on the grayish abutment, which has a good aesthetic performance. Reference | Related Articles | Metrics

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Effect of polishing method and time on the fitness of CAD/CAM zirconia ceramic crown ZHAO Chen, BAI Yue-hui, LIU Yang, JIANG Shan-shan, SHANG Qing-long, ZHAO Tian-tian, YUAN Shuo, LI Ning, JIAO Jian-ping Shanghai Journal of Stomatology    2023, 32 (3): 236-240.   DOI: 10.19439/j.sjos.2023.03.003 Abstract （465）      PDF （870KB）（259）       Knowledge map    PURPOSE: To compare the effect of different polishing methods and time treatment on the fitness of CAD/CAM zirconia ceramic crowns. METHODS: Sixteen intact maxillary premolars were randomly divided into two groups, group A was treated with silicon carbide burs, while group B was treated with tungsten steel burs. At different polishing time points of the same tooth, digital impressions of each group were obtained, which were used to manufacture CAD/CAM zirconium ceramic crowns. After trial fitting, the gap impressions were obtained by using silicone rubber replication method, and the marginal and internal discrepancies were assessed. The data were statistically analyzed with SPSS 21.0 software package. RESULTS: The difference between the gap values of the marginal and internal markers of group A and group B was not statistically significant(P>0.05). Compared with the no-polishing process, the differences of the marginal gap (39.67±8.35) μm and internal gap (45.18±7.16) μm of group A polished for 4 min, and the marginal gap (51.25±14.73) μm, and internal gap (48.56±6.45) μm of group B polished for 3 min, as well as the marginal gap (48.87±8.90) μm, and internal gap (45.99±7.12) μm of group B polished for 4 min, were all significant(P<0.05). CONCLUSIONS: CAD/CAM zirconia ceramic crowns treated with silicon carbide bur for polishing 4 min and tungsten steel for 3 min has the best fitness. Reference | Related Articles | Metrics

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Analysis of the use status of internet outpatient in stomatological departments based on AI follow-up TAO Mao-mao, LIU Jun, LIAO Qian, WANG Xu-dong Shanghai Journal of Stomatology    2023, 32 (2): 183-187.   DOI: 10.19439/j.sjos.2023.02.013 Abstract （461）      PDF （657KB）（215）       Knowledge map    PURPOSE: To analyze the use status and satisfaction of the follow-up patients, and explore the construction of internet medical service model and platform in stomatology. METHODS: Patients who visited the internet clinic of stomatology from January to June, 2021 were selected. After diagnosis and treatment, they were followed up by AI intelligent voice with self-designed questionnaire. SPSS 21.0 software was used for statistical analysis. RESULTS: A total of 372 valid questionnaires were collected. The male-to-female ratio of oral patients was 1.25:1, with an average age of 35.96 years. Most of them had a bachelor's degree or above, and the patients were mainly from the Yangtze River Delta. 53.76% of patients needed doctors to prescribe drugs. 81.72% of the dental patients believed that the consultation process of internet clinic was convenient, and 79.83% of patients perceived that the system operation of internet clinic was convenient. Binary logistic regression showed that digital literacy, convenience of medical treatment process were significantly related to the satisfaction of internet outpatient service, while gender, education level, online medical treatment duration and convenience of system operation were not related. CONCLUSIONS: Internet medical treatment in stomatology is feasible, but it is still necessary to break through limitations and further innovate service function. Internet outpatients are mainly young and middle-aged, but it is still necessary to care for the special group of the elderly. It is necessary to further optimize the process, upgrade the system and innovate management, strengthen policy support and incentive mechanism, and promote the transformation of medical service mode in stomatology. Reference | Related Articles | Metrics