In the field of prosthodontics,the use of virtual patients for biomimetic restoration holds great promise for various applications.Virtual patients consist of digitized data that encompasses details on the morphology,struc-ture,and spatial relationships within the maxillofacial and intraoral regions.Nonetheless,there are several challenges associated with acquiring digital data,achieving accurate alignment,and recording and transferring dynamic jaw movements.This paper aims to concentrate on the process of constructing virtual patients,highlight the key and chal-lenging aspects of virtual patient construction,and advocate for the extensive adoption and utilization of virtual patient technology.

With the development of periodontal regenerative technology,an increasing number of scholars reported that advanced periodontitis involving teeth can be preserved through intentional replantation.Intentional replantation has become the last possible method to preserve natural teeth for advance periodontitis with signs of tooth extraction.Howev-er,the indications of intentional replantation are strict,and the success of the operation is closely related to the condition of cases and the operation skills of doctors.In this article,the operation steps and criteria of intentional replantation were summarized by introducing three success cases of advanced periodontitis involving teeth preserved by intentional replan-tation.The relevant factors that affect the prognosis of intentional replantation in advanced periodontitis involving teeth preservation were analyzed to help clinicians preserve natural teeth.

At present,the commonly used clinical protocols of oral comestic restoration are mostly based on the aes-thetic indicators proposed by Western developed countries(referred to as Western aesthetics).Mechanically copying the Western aesthetic scheme,ignoring the difference between it and the Chinese oral aesthetic indicators(referred to as Chinese aesthetics),is unable to effectively support personalized cosmetic restoration diagnosis and treatment.In addition,new technologies and new solutions for cosmetic restoration,which are developing rapidly in recent years,are emerging one after another,but many popular concepts are confusing and lack of proper hierarchical diagnosis and treatment norms,and there is indeed an urgent need for discussion and clarity.From the perspective of serving clinical application,this paper discusses the deficiencies of the Chinese translation of the word"aesthetics",the diffe-rence and connection between aesthetics and cosmetolo-gy,and the relationship between cosmetic restoration and fixed restoration.It also discusses the difference be-tween anterior teeth,esthetic zone and exposed zone,the diagnostic and therapeutic value of oral aesthetic analysis,as well as the application methods of desensitization,suggestion,and other therapies in difficult oral cosmetic restoration cases.We further introduce the decision tree and the clinical pathway for restoration and reconstruction of teeth in ex-posed zone guided by aesthetic analysis,and introduce the clinical process of aesthetic analysis and evaluation,the clinical triclassification of oral cosmetic restoration,and the corresponding clinical classification diagnosis and treat-ment points.

Objective This study aims to compare the osteogenic effects of implanting demineralized dentin matrix and acellular dentin matrix in bone defect areas.Methods Demineralized dentin matrix and acellular dentin matrix were prepared.Twenty-four male SPF-grade SD rats were randomly divided into four groups:demineralized group(group A),acelluar group(group B),Bio-Oss bone powder group(group C),and blank control group(group D),with six rats in each group.All rats were subjected to general anesthesia to prepare bilateral femoral bone defects.Rats in groups A,B,and C were implanted with demineralized dentin matrix,acellular dentin matrix,and Bio-Oss bone powder at the bone defect area,respectively,while rats in group D were not implanted with any material.At 4 and 8 weeks after surgery,three rats were randomly executed in each group.The healing of the bone defect area was ana-lyzed through gross observation.The concentrations of osteogenic indicators bone morphogenetic protein-2(BMP-2)and alkaline phosphatase(ALP)were detected by serology.The distribution of high-density gray area(representing bone healing)in the bone defect area was observed by X-ray examination,and the formation of new bone was observed by his-tomorphology.The rate of new bone formation was calculated.Results At 4 and 8 weeks,the bone formation ability of group A was more active than that of the other groups;the concentrations of BMP-2 and ALP in group A were higher than those in the other groups,and the differences were statistically significant(P<0.05).At 8 weeks,the imaging obser-vation showed that the high-density gray area in the bone defect of group A was evenly distributed.The histomorphologi-cal observation showed the regular arrangement of bone matrix in group A.The rate of new bone formation in group A was 28.51%±0.55%at 4 weeks and 32.57%±2.28%at 8 weeks,both of which were significantly higher than those in the other groups(P<0.05).Conclusion Demineralized dentin matrix has better osteogenic potential than acellular dentin matrix.

Objective This study aimed to investigate the effects of sitagliptin on the proliferation,apoptosis,in-flammation,and osteogenic differentiation of human periodontal ligament stem cells(hPDLSCs)in lipopolysaccharide(LPS)-induced inflammatory microenvironment and its molecular mechanism.Methods hPDLSCs were cultured in vitro and treated with different concentrations of sitagliptin to detect cell viability and subsequently determine the exper-imental concentration of sitagliptin.An hPDLSCs inflammation model was established after 24 h of stimulation with 1 μg/mL LPS and divided into blank,control,low-concentration sitagliptin(0.5 μmol/L),medium-concentration sita-gliptin(1 μmol/L),and high-concentration sitagliptin(2 μmol/L),high-concentrationsitagliptin+stromal cell derived factor-1(SDF-1)/CXC chemokine receptor 4(CXCR4)pathway inhibitor(AMD3100)(2 μmol/L+10 μg/mL)groups.A cell-counting kit-8 was used to detect the proliferation activity of hPDLSCs after 24,48,and 72 h culture.The apoptosis of hPDLSCs cultured for 72 h was detected by flow cytometry.After inducing osteogenic differentiation for 21 days,alizarin red staining was used to detect the osteogenic differentiation ability of hPDLSCs.The alkaline phosphatase(ALP)activity in hPDLSCs was determined using a kit.The levels of inflammatory factors[tumor necrosis factor(TNF)-α,interleukin(IL)-1β,and IL-6]in the supernatant of hPDLSCs culture were detected by enzyme-linked immu-nosorbent assay.The mRNA expressions of osteogenic differentiation genes[Runt-associated transcription factor 2(RUNX2),osteocalcin(OCN),osteopontin(OPN)],SDF-1 and CXCR4 in hPDLSCs were detected by real-time fluores-cence quantitative polymerase chain reaction(RT-qPCR).Western blot analysis was used to determine SDF-1 and CX-CR4 protein expression in hPDLSCs.Results Compared with the blank group,the proliferative activity,number of mineralized nodules,staining intensity,ALP activity,and RUNX2,OCN,OPN mRNA,SDF-1,and CXCR4 mRNA and protein expression levels of hPDLSCs in the control group significantly decreased.The apoptosis rate and levels of TNF-α,IL-1β,and IL-6 significantly increased(P<0.05).Compared with the control group,the proliferative activity,number of mineralized nodule,staining intensity,ALP activity,and RUNX2,OCN,OPN mRNA,SDF-1,and CXCR4 mRNA and protein expression levels of hPDLSCs in low-,medium-,and high-concentration sitagliptin groups in-creased.The apoptosis rate and levels of TNF-α,IL-1β,and IL-6 decreased(P<0.05).AMD3100 partially reversed the effect of high-concentration sitagliptin on LPS-induced hPDLSCs(P<0.05).Conclusion Sitagliptin may promote the proliferation and osteogenic differentiation of hPDLSCs in LPS-induced inflammatory microenvironment by activating the SDF-1/CXCR4 signaling pathway.Furthermore,it inhibited the apoptosis and inflammatory response of hPDLSCs.

Objective This study aimed to explore the effect of pituitary tumor-transforming gene 1(PTT-G1)on the invasion and proliferation of oral squamous cell carcinoma(OSCC)cell lines under the action of miR-362-3p.Methods The bioinformatics online database was used to query the expression of PTTG1 in head and neck squamous cell carcinoma(HNSCC).The expression of PTTG1 in the Cal-27,HN-30,and HOK cell lines was detected by Western blot.A wound-healing assay was used to determine the effect of PTTG1 on the migration ability of the OSCC cells.The Transwell assay was used to examine the changes in cell-invasion ability.5-ethynyl-2'-deoxyuridine(EdU)cell-proliferation assay was used to detect changes in cell-proliferation ability.Bioinformatics approach predicted the upstream miRNA of PTTG1.The targeting relationship between miR-362-3p and PTTG1 was examined by the dual luciferase assay,and quantitative real-time polymerase chain reaction(qRT-PCR)was used to determine the expression of miRNA in OSCC tissues.Results The ENCORI database showed that PTTG1 expression was up-regulated in OSCC tissues.Western blot confirmed that PTTG1 expression was up-regulated in Cal-27 and HN-30 cells than HOK cells.PTTG1 knockout can inhibit the migration,invasion,and prolif-eration of Cal-27 and HN-30 cells(P<0.05).Bioinformatics prediction websites predicted that the upstream miRNA of PTTG1 was miR-362-3p,and PTTG1 can bind to miR-362-3p.Results of qRT-PCR showed that miR-362-3p expression was downregulated in OSCC tissues compared with normal tissue(P<0.05).Transwell and EdU experiments confirmed that miR-362-3p knockdown can promote the invasion and proliferation of Cal-27 and HN-30 after PTTG1 knockdown.Conclusion miR-362-3p can inhibit the invasion and proliferation of Cal-27 and HN-30 cells by targeting PTTG1.

Objective This study aimed to evaluate the influence of ceramic type and thickness on the masking abili-ty and final aesthetic effects of chairside machinable all-ceramic crowns.Methods Six kinds from three types chairside machinable ceramic materials(IPS e.max CAD HT/MT/LT,IPS Empress LT,and VITA Suprinity HT/T)in shade A2 were fabricated to slice specimens into 1.0,1.5,and 2.0 mm-thick sections(n=10).The color parameters of the speci-mens against black and white tiles and four resin substrates(A2,A4,B3,and C4 shade)were measured with a spectro-photometer.The translucency parameter(TP)was calculated using color parameters measured over standard white and black backgrounds.The color differences(ΔE)were cal-culated between there substrate shades(A4,B3,C4)and A2 shade(control group).Two-way analysis of variance(ANOVA)was performed on the TP values.The two va-riables were ceramic type and ceramic thickness.Three-way ANOVA was used to determine the effects of ceramic materials,ceramic thickness,and substrate shades on the ΔE values,followed by Tukey test for multiple comparisons(α=0.05).Results Ceramic type,ceramic thickness,and sub-strate shade significantly affected the ΔE values(P<0.001).The L* and b* values of the specimens increased with in-creasing ceramic thickness,except in substrate A2,whereas the ΔE values decreased.The color difference of all 1.0 mm-thick specimens or all specimens over the substrates C4 shade exceeded the clinically acceptable threshold(ΔE>3.3).Conclusion The masking ability of chairside machinable all-ceramic crowns is influenced by ceramic type and thick-ness,and ceramic material.The thickness of ceramic less than 2.0 mm cannot mask the gray shade abutment.

Objective This work aimed to evaluate the effect of speed sintering and low-temperature degradation on the translucency of high-translucent zirconia.Methods The ST and TT specimens were randomly divided into two groups depending on the sintering process:conventional sintering and speed sintering.The sintered specimens were divided into three subgroups according to the aging time:aged for 0,5,and 20 h.Chromatic parameters(L*,a*,and b*values)were measured by Shade Eye NCC computer colorimeter in a dark environment under black and white back-ground,and the translucency parameter(TP)was used to evaluate the translucency of zirconia.Results Speed sintering may decrease the TP of ST and increase the TP of TT.As for the effect of low-temperature degradation on the translucen-cy of zirconia,the TP of ST decreased with the extension of aging time,and no significant difference was found in rapid sintering ST.Although the TP of TT decreased,no statistical difference was observed.Conclusion Speed sintering may decrease the translucency of high-strength zirconia and increase the translucency of high-translucent zirconia.Low-tem-perature degradation had no effect on the translucency of high-translucent zirconia.Speed sintering can be recommended for high-translucent zirconia in terms of translucency.

Objective This clinical study aimed to evaluate the accuracy of a fully digital technique for mea-suring sagittal condylar inclination(SCI),as well as vali-dating whether differences existed between the left and right SCI values of the same participant,to provide a ref-erence for clinical practice.Methods Ten participants with good occlusal relationship and normal temporomandibular joint were recruited.Three methods were used to mea-sure the SCI values of the participants,namely,A(mechanical facebow transferring and mechanical articulator-based measuring method with physical protrusive interocclusal registration),B(face scan-based virtual facebow and virtual ar-ticulator-based measuring method with digital protrusive interocclusal registration),and C(jaw motion tracking system-based measuring method).With the group subjected to methods A and C as the control,the SCI values obtained by the three methods were statistically analyzed.The left and right SCI values of the same participant were also compared.Re-sults The left and right SCI values measured by method A were 41.70°±7.09° and 42.80°±8.62°,those by method B were 35.09°±12.49° and 37.63°±12.10°,and those by method C were 39.43°±8.72° and 38.45°±6.91°.No significant dif-ference existed among the SCI values measured by the three methods(P>0.05).Meanwhile,no statistical difference existed between the SCI values on the left and right sides of the same participant(P>0.05).Conclusion The accuracy of the virtual facebow and digital protrusive occlusal registration based SCI measuring method was the same as that of mechanical facebow based and jaw motion tracking system-based methods.The SCI values on the left and right sides of the same participant were similar.Clinically,an appropriate SCI measurement and setting strategy can be selected based on the actual situations.

Objective This study aimed to compare the differences among four kinds of mechanical Ni-Ti files in-cluding T-Flex,Reciproc Blue(RB),ProTaper Gold(PTG),and ProTaper Universal(PTU)in dentinal microcrack genera-tion after root canal preparation in vitro by using micro-computed tomography(micro-CT)analysis.Methods A total of 32 freshly extracted double-root-canal premolars with an angle not exceeding 10° were selected and established as root canal preparation models in vitro.Then,the specimens were randomly assigned to four experimental groups(n=8)according to the different Ni-Ti systems used for root canal preparation:group T-Flex,group RB,group PTG,and group PTU.The voxel size of the micro-CT was set at 17.18 μm.Pre-and post-operative cross-sectional images of roots(n= 56 940)were scanned and analyzed to identify the presence of dentinal microcracks.The results of each group were ex-pressed by the quantity and percentage of sectional images with microcracks.McNemar test was used to determine whether a significant difference existed in the existence of dentinal microcracks before and after instrumentation.The level of significance was set at P<0.05.Results Overall,11.04%of the images presented dentinal defects(n=6 288).Dentinal microcracks were observed in 9.82%,10.79%,12.27%,and 11.25%of the post-instrumentation images from groups T-Flex,RB,PTG,and PTU,respectively.However,all these dentinal microcracks were already present in the corresponding pre-operative images.No new microcrack of premolars were generated after the root canal prepara-tion utilizing the aforementioned systems.Conclusion Denti-nal microcracks already existed in advance in extracted teeth before root canal preparation.Root canal preparation using the T-Flex,RB,PTG,and PTU systems did not induce the formation of new dentinal microcracks on the straight root canals of premolars.