Sinus lift procedure aims to increase bone volume to install dental implants in the maxillary posterior region, and includes lateral sinus floor elevation and trans-crestal sinus floor elevation. Compared with lateral sinus floor elevation, trans-crestal sinus floor elevation has advantages of less invasiveness, shorter operation time and more acceptance among patients, which is widely used in clinical practice nowadays. Many factors may affect bone regeneration and implant success after lifting. Anatomic factors are one of the most important factors. This article will review and analyze main anatomic factors, such as remaining alveolar bone, maxillary sinus characteristics, maxillary sinus width, maxillary sinus morphology and etc., in order to provide reference for the application of trans-crestal sinus floor elevation in clinical practice.

Objective To observe the effect of long-term chronic intermittent hypoxia caused by obstructive sleep apnea hypoxia on three-dimensional structure and morphology of mandible. Methods Twelve 8-week-old male C57BL/6 mice were divided into two groups randomly. The CIH group was fed with intermittent hypoxia and the control group was fed with normoxia. Four weeks later, the two groups were killed by being excessively anesthetized and the right mandible was detected using micro CT analysis. Morphological changes of mandibles were detected with Hematoxylin-esoin staining. Results At four weeks after modeling, the micro CT technique was used to observe the three-dimensional structure of mandibles in two groups. The quantitative analysis on the microstructure of cancellous bone showed that bone mass in the region of interest in CIH mice were significantly decreased when compared to the control group (P<0.05). Hematoxylin-esoin staining showed that the number and volume of mandibular trabecular of CIH mice were decreased. The results suggested that three-dimensional structure and microstructure of the cancellous bone in CIH mince changed significantly. Conclusion Chronic intermittent hypoxia inhibits bone formation and affects bone metabolism.

Objective To investigate the effect of asperosaponinⅥ(ASAⅥ) on the osteogenic differentiation of human jaw bone marrow mesenchymal stem cells (hjBMSCs). Methods Specific antigens of hjBMSCs were identified by flow cytometry analysis. The effect of 1×10^-4, 1×10^-5, 1×10^-6, 1×10^-7, 1×10^-8 mol/L ASAⅥ on hjBMSCs' proliferation was detected by CCK8 kit; BCIP/NBT, alizarin red stain (ARS) and western-blot (WB) were used to verify the role of ASAⅥ in promoting hjBMSCs' osteogenic differentiation and to determine the appropriate concentration of ASAⅥ. The effect of ASAⅥ on the osteogenic differentiation of hjBMSCs at mRNA level was further explored by real-time quantitative PCR(RT-PCR). Results Results showed that 1×10^-4mol/L ASAⅥ had obvious toxic effects on hjBMSCs (P<0.01), while the others had no obvious side effect on cell proliferation. Alkaline phosphatase, calcium nodule precipitation, and the expression of osteogenic differentiation-specific proteins were all significantly increased in the 1×10^-5, 1×10^-6 mol/L ASAⅥ group when compared with the control group. The expression of Runx2, OCN and COL-Ⅰ at mRNA level were significantly increased in the 1×10^-5, 1×10^-6 mol/L groups compared to the control group (P<0.01), and the former was slightly predominant. Conclusion The 1×10^-5, 1×10^-6 mol/L ASAⅥ can better promote hjBMSCs' osteogenic differentiation, and 1×10^-5 mol/L group is slightly better.

Objective To compare physicochemical properties and biocompatibility of cobalt-chromium (Co-Cr) alloy in 3D printing technology and conventional alloy casting technique. Methods The experimental group and the control group each contained 10 Co-Cr alloy specimens fabricated by selective laser melting (SLM) and traditional casting technology respectively. The Rockwell hardness tester HR-150A and the metallurgical microscope were used to compare two groups respectively, and then polarization curve was measured on metal specimens under self-corrosion potential. Leaching solution of the test piece was prepared in a sterile environment, and was divided into negative control group, 3D printing Co-Cr alloy group and cast Co-Cr alloy group (5 per group). Using CCK-8 reagent, the cytotoxicity of the extract to mouse fibroblast L-929 was determined, and the apoptosis was detected by AnnexinⅤ-FITC/PI fluorescence staining; the apoptosis rate of different groups was calculated by flow cytometry. Results The Rockwell hardness of the 3D printing group and the casting group were 70.6±0.1 and 68.5±0.2, respectively. The 3D printing group was stronger than the casting group, and the difference between two groups was statistically significant (P<0.005). The 3D printed Co-Cr alloy structure didn’t have a second phase; the cast structure was dendritic, and the second phase was strengthened. The current densities of the 3D printing and casting groups of Co-Cr alloys under self-corrosion potential were 4.338 1×10^-9 A/cm² and 3.378 5×10^-8 A/cm², respectively. The current density of the casting group was higher than that of the 3D printing group. At 24, 48 and 72 h, the average OD of the negative control group was approximately 0.44, 1.14, 1.50, the 3D group was 0.39, 0.95, 1.09, the casting group was 0.35, 0.76, 1.01. The differences in cytotoxicity between groups were statistically significant (P<0.05). The casting group had the strongest cytotoxicity, and the cytotoxicity of each group gradually increased with time. Flow cytometry suggested primarily normal cells existed in three groups, and the apoptotic rates were (2.497±0.121)%, (3.513±0.055)%, (5.407±0.401)%, and there was statistical significance among each group (P<0.01). Conclusion Compared with traditional casting technology, the cobalt-chromium alloy using 3D printing technology has better mechanical properties and biocompatibility, and has better prospect for clinical application.

Objective To analyze the protein carbonyl (PC) levels in plasma and gingival crevicular fluid (GCF) in patients with chronic periodontitis (CP), and evaluate protein oxidative damage in oxidative stress caused by CP. Methods Twenty-four CP patients and 22 health controls were enrolled in this study. All subjects had an oral examination. Peripheral blood and GCF were obtained. PC levels in plasma and GCF were detected. The correlation between PC levels and periodontal clinical parameters was analyzed. Results Compared with health controls, PC levels in plasma and GCF were significantly higher in CP patients (P<0.001). There were positive correlations between PC levels and plaque index, gingiva index, probing depth and clinical attachment level. Conclusion Levels of PC in plasma and GCF increase in CP patients, which indicates protein oxidative damage caused by periodontitis. PC could be a potential indicator for assessing periodontal inflammation.

Objective To systematically analyze the prevalence and treatment of localized juvenile spongiotic gingivitis hyperplasia (LJSGH). Methods Related literature from January 2007 to May 2021 was retrieved from Wanfang Database, CNKI, PubMed, Metstr and Qf Academic databases, and included literature was systematically reviewed after screening. Results A total of 20 pieces of literature were included, and 221 cases of LJSGH were reported, including 127 males and 94 females. The mean age was 15.2.The etiology and pathogenesis of all cases have not been reported. Microscopically, significant intercellular edema (spongiotic structure) and strong positive cytokeratin (CK) 19 across epithelium of the lesion were main characteristics.171 patients only had lesions in the maxilla, and LJSGH was more common in the anterior teeth than in the posterior teeth or in both the anterior and posterior teeth. The affected gingival was usually bright red with clear boundary and papillary, granular or velvety surface. The main treatment was surgery, and the recurrence rate was 13.8%. A few cases were treated with photodynamic therapy, cryotherapy or drug therapy. Conclusion LJSGH occurs mostly in children and juvenile, but also in adults. Although the etiology and pathogenesis are not clear, its unique pathological features and immunohistochemical staining have clinical values in diagnosis, and differential diagnoses should be paid attention to in clinical diagnosis and treatment.

Objective To analyse Candida albicans infection in patients with oral mucosal diseases. Methods A total of 2 289 patients who visited the Department of Oral Mucosal Disease in 2019 and underwent Candida albicans culture were collected. Clinical and laboratory data were collected on each patient. They were grouped by age:0-16 years old(Group 1, 38 patients), 17-29 years old (Group 2, 181 patients), 30-39 years old (Group 3, 274 patients), 40-49 years old (Group 4, 325 patients), 50-59 years old (Group 5, 535 patients), 60-69 years old (Group 6, 540 patients), 70 years and older (Group 7, 396 patients). Results The total infection rate of Candida albicans was 30.6%, and the infection rate of female patients was higher than that of males (33.1% vs. 25.1%, P<0.05). The overall rate of Candida albicans infection increased with age, and the infection rate in Group 6 and 7 was significantly higher than that in Group 2, 3, 4, and 5 (P<0.05). In addition to oral candidiasis itself, Candida albicans was most easily detected in labial and lingual diseases and oral marking diseases, and the positive detection of Candida albicans was associated with labial and lingual diseases, Sjogren′s syndrome, and oral marking diseases, etc. Among patients who had both candida albicans culture and fungal microscopy, the fungal microscopy was positive in 50 patients who had a positive Candida albicans culture and the positive rate was 35.5%. The topical treatment of patients with positive culture of Candida albicans, using nystatin tablets and 2%-3% sodium bicarbonate solution, resulted in a drug response rate of 81.36%. Conclusion Oral candidiasis is more likely to occur in elderly women over 60, and is associated with systemic diseases and oral marking diseases. The efficacy of topical treatment of oral candidiasis using the combination of nystatin tablets and 2%-3% sodium bicarbonate solution is acceptable.

Objective To compare the application of iRoot BP Plus and inorganic trioxide polymer (MTA) in immature permanent teeth with pulp revascularization. Methods A total of 100 patients (100 teeth) with pulp revascularization in our hospital were selected. According to the use of filling materials, there were 50 cases in MTA group (50 teeth, 2 cases lost to follow-up) and 50 cases in iRoot BP Plus group (50 teeth, 1 case lost to follow-up). The root development, root canal wall thickness and root length, old periapical index (O-PAI) changes at different time, clinical efficacy and complications were compared between the two groups. Results The developmental typing of iRoot BP Plus group was better than MTA group (χ²=2.21,P<0.05); the measurement results of root canal wall thickness, root length and growth rate in iRoot BP Plus group were higher than those in MTA group (t=3.511, 3.342, 9.983, 10.638, P<0.05). The O-PAI rating of iRoot BP Plus group at 12 months and 24 months was lower than that of MTA group (t=8.570, 8.268, P<0.05). The total effective rates of MTA group and iroot BP plus group were 89.80% and 97.96% respectively, and the difference was statistically significant (χ²=4.461,P<0.05). The incidence of complications in MTA group and iRoot BP Plus group were 32.65% and 6.12% respectively, with significant difference (χ²=20.854,P<0.05). Conclusion iRoot BP Plus has better effect than MTA on immature permanent teeth with pulp revascularization. Moreover, it is more conducive to root development and control of complications.

Objective To investigate the importance of root-bone information through comparison of root position in diagnostic model set up with the traditional crown models and the composite tooth models. Methods Traditional digital models obtained by intraoral scanner were collected from 11 patients with facial asymmetry. The CBCT-based model and traditional digital model were registered and integrated to create a pretreatment composite tooth models. The P1 and P2 diagnostic model setup were respectively performed on the traditional digital model and composite tooth model by a professional i-align technician. CBCT-based model was put into P1 and P2 virtual setup to obtain composite tooth models. Mobility design, root exposure and root parallelism were compared between P1 and P2 composite tooth models. Results Nonparallel and exposure of the roots were found in P1 composite tooth model. In P2, the nonparallel and exposure of the root have been improved. By comparison,the mobility design difference of P2 were mainly the buccolingual movement and torque of deviated teeth and some non-deviated posterior teeth, as well as the mesiodistal movement of some anterior teeth. Conclusion Invisalign design system containing root-bone information can help optimize diagnostic model and improve fenestration, dehiscence and root parallelism.

Objective To investigate the clinical effect of a new restoration method of all-porcelain prefabricated crown on large defect of deciduous molars. Methods One hundred and twenty deciduous molars with large defect were randomly divided into three groups:A, B and C. Group A was treated with composite resin, group B with porcelain prefabricated crowns, and group C with metal prefabricated crowns. The restoration success rate at 6 months and 12 months was compared among three groups. Results There was no statistically significant difference in the 6-month repair success rate among groups A, B and C (P>0.05). The success rate at 12 months in group B and C was significantly higher than that in group A (P<0.05). Conclusion All-porcelain prefabricated crowns and metal prefabricated crowns have significant effect on the restoration of large defect of deciduous molars. The long-term success rate of restoration is higher than that of composite resin restoration, and can be accepted by children and parents. It is worth being widely promoted in clinical practice.

Objective To evaluate the effect of a modified guided bone regeneration technique on reducing the incidence of complications during bone healing based on 3D printing personalized titanium mesh technology. Methods From September 2019 to July 2021, 9 patients aged 45.6±8.0 with severe residual alveolar bone deficiency (9 bone graft areas and 24 denture sites) were enrolled in the Department of Stomatology, the First Affiliated Hospital of Dalian Medical University. Implants were simulated in the software guided by prosthetics and biology, then the personalized titanium mesh was designed and manufactured by 3D printing. Intraoperatively, the bone graft material was overfilled with 1 mm based on the profile of the personalized titanium mesh, and then the absorbable collagen membrane was covered on the surface to fix the bone graft material. Guided bone regeneration surgery was completed for 9 patients. During postoperative healing, 9 patients were observed for incision dehiscing, titanium mesh exposure, surrounding soft tissue infection and the formation of “pseudoperiosteum” at the bone graft site. Results ①Temporary skin numbness in mental region occurred in 1 of 9 patients, which was relieved at the 6^th month and almost disappeared at the 9^th month. ②14 days after surgery, two patients were found to have wound edge dehashes of about 2 mm during suture removal, and only absorbable collagen membrane was exposed, but titanium mesh was not exposed, and no infection occurred. The soft tissue healed at the follow-up visit 1 month after surgery. ③During the follow-up of 1 to 9 months after surgery, no complications such as soft tissue dehiscing, titanium mesh exposure and infection were observed in all patients. ④No obvious formation of fibrous connective tissue, namely “pseudoperiosteum”, was observed on the surface of all grafts after the titanium mesh was removed. Conclusion In the application of 3D printed personalized titanium mesh technology to guide bone regeneration, an excessive bone graft implantation combined with absorbable collagen membrane covering can double isolate the direct contact between titanium mesh and mucous membrane, and can effectively reduce complications such as incision dehashes, titanium mesh exposure and infection.

Infection, trauma, diabetes mellitus, postmenopausal osteoporosis, and some metabolic diseases can cause alveolar bone defects after tooth extraction, which challenges the implant placement. Alveolar ridge augmentation was frequently used for implant placement with the usage of bone substitutes including autogenous bone, allogenic bone, xenogenic bone, and synthetic bone substitutes. Currently, the autogenous tooth becomes an alternative material of alveolar ridge augmentation. This review compared different types of tooth graft materials for defection sites, discussed biological characteristics of autogenous tooth materials, and potential factors that affected graft applications, specifically the success rate in alveolar ridge augmentation.

Enamel biomimetic mineralization is a significant issue in the science of dental materials. Chitosan is a natural cationic polysaccharide, whose chemical structure and biological behaviors are similar to components of the extracellular matrix of enamel. Its excellent biocompatibility and polyelectrolyte action make it a suitable carrier or an organic template. In recent years, chitosan-based biomimetic organic-inorganic composite materials have been applied in the field of enamel biomimetic mineralization. This is mainly focused on the basic theories and applications of chitosan in promoting enamel biomimetic mineralization.

Oral lichen planus (OLP) is a chronic inflammatory disease of unknown etiology, and is closely related to autoimmunity. Corticosteroids and immunosuppressants are commonly used drugs for OLP treatment, but some OLP patients show insensitivity or treatment resistance. Research suggests that biologics have advantages for OLP patients that are not sensitive or are resistant to conventional drug treatment. This article reviews the types, mechanisms, efficacy, prognosis, and adverse reactions of biologics for OLP treatment and provides references for the treatment of OLP.

Cell senescence caused by various factors restricts the application of mesenchymal stem cells (MSCs) in oral tissue regeneration. However, part of small molecule compounds could delay the senescence of MSCs and extend characteristics of stem cells. This article introduces features of senescent MSCs, and summarizes possible therapeutic targets together with mechanisms of hotspot small molecule compounds, so as to supplement certain theoretical basis for promoting the future development of oral regenerative medicine.

The mandibular central incisor as orthodontic guidance often moves in a large scale, and the thickness of alveolar bone in this area is relatively thin, which is prone to dehiscence, fenestration, and other undesirable effects in the process of orthodontic treatment. Therefore, it has great clinical significance to fully understand measuring tools and influencing factors of alveolar bone thickness in the lower middle incisor area. At present, observation of the alveolar bone in the lower central incisor area is mainly conducted through cone beam computed tomography(CBCT), and its main influencing factors are vertical bone type, sagittal bone type, lower incisor inclination, age, gender and so on. Although numerous studies have been done in this field, a consensus on such issue has not be achieved. The purpose of this paper is to summarize the CBCT measurement of alveolar bone in the lower central incisor area and the influencing factors of its thickness before orthodontic treatment, in order to provide instruction for clinical practice.

Oral lichen planus (OLP) is a common chronic immune inflammatory disease that affects oral mucosa. However, the exact etiology of OLP has not yet been elucidated and valid diagnosis and treatment for OLP is inhibited by some factors with OLP itself a risk factor for malignant transformation. Therefore, research on the pathogenesis of OLP and treatment for OLP has been receiving much attention. In recent years, some studies have shown that OLP is closely related to human β defensin-2 (hBD-2). This paper attempts to summarize and analyze recent research progress of OLP and hBD-2.

In recent years, clinical vital tooth bleaching technology has been widely promoted and used, and various new technologies are still mainly focused on improving the bleaching effect of peroxides and exploring the most reasonable application methods of peroxides. However, peroxides can also cause side effects such as tooth sensitivity and decreased enamel microhardness. How to improve the effect of whitening on the premise of preventing damage of peroxides to dental pulp and other dental tissues is a main research topic in the field of vital tooth bleaching. Therefore, this review summarizes current research on clinical effects of vital bleaching technology, the side effects of peroxides and related advances in preventive measures.

Digital impression is an efficient and convenient new impression technology. In recent years, it has shown good accuracy and clinical efficacy in fixed crown, dental implant and removable partial denture. Meantime, it simplifies the workflow, and makes patients feel more comfortable. The impression of edentulous jaw has always been the key and difficult point in clinical diagnosis and treatment. Nowadays, the application of digital impression in edentulous patients has been increasing. In this paper, classifications, accuracy and clinical scanning strategies of digital impression in edentulous jaw will be reviewed to provide a new idea for edentulous jaw impression.