Objective:To investigate the impact of four registration methods on the accuracy of virtual occlusal records (VOR) in intraoral scanning for implant restorations with multiple missing teeth.Methods:A mandibular model simulating clinical conditions with multiple missing teeth (right first molar, left second premolar, left first molar, left second molar) and a maxillary compete dentition model were mounted on a semi-adjustable articulator. Subsequently, twelve 0.5 mm stainless steel spheres were adhered to reference positions (16, 46, 13, 43, 23, 33, 25, 35, 26, 36, 27, 37) as fiducial markers. Following this, a laboratory scanner generated reference datasets by digitizing the models in maximum intercuspation (MIP). Meanwhile, ten maxillary and mandibular scans were acquired using an intraoral scanner, with all nonarticulated scans duplicated four times to ensure data consistency. Forty VOR intraoral scans were performed in MIP using four registration protocols: left-side, right-side, anterior, and bilateral registration ( n=10 per group), randomized via a computer-generated pseudo-random sequence. For measurement, linear distances (D16-46, D13-43, D23-33, D25-35, D26-36, D27-37, D16-46 represented the single-tooth defect position, whereas D25-35, D26-36, D27-37 reflected positions in free-end edentulism areas) between opposing markers were measured in a reverse engineering software, with deviations (ΔD) from the reference scan calculated to assess accuracy. Specifically, negative ΔD values indicated vertical dimension underestimation. Given that non-normally distributed data were analyzed using medians [interquartile ranges (IQR)], trueness (median ΔD) and precision (IQR) were evaluated. The interaction effect between the registration method and the position of the measurement items was evaluated by using the generalized linear model. The accuracy was compared overall by the Kruskal-Wallis test with the two-sided significance level of α=0.05. For pairwise comparisons, post-hoc tests were conducted by Dunn′s t-test with the Bonferroni correction for the significance level. Results:The accuracy of VOR was affected by registration method ( P<0.05), with a significant position×registration method interaction observed ( P<0.05). In particular, in all four groups, only the bilateral registration group showed trueness of less than 0.1 mm for both free-end edentulism and the single tooth defect, with ΔD16-46, ΔD25-35, ΔD26-36, and ΔD27-37 being 0.059 (0.015), -0.082 (0.052), -0.065 (0.032), -0.070 (0.050) mm, respectively. Moreover, trueness in free-end edentulism showed negative values across all groups, with the largest negative deviations observed in the right-side registration group, with ΔD25-35, ΔD26-36 and ΔD27-37 being -0.410 (0.174), -0.442 (0.225), -0.439 (0.262) mm, respectively. Conclusions:In fully digital workflows of implant restorations for mandibular free-end edentulism with multiple missing teeth, registration method critically influences VOR accuracy. While four registration methods exhibited underestimation of occlusal vertical dimension, bilateral registration achieved the highest accuracy.

Objective:To investigate the impact of four registration methods on the accuracy of virtual occlusal records (VOR) in intraoral scanning for implant restorations with multiple missing teeth.Methods:A mandibular model simulating clinical conditions with multiple missing teeth (right first molar, left second premolar, left first molar, left second molar) and a maxillary compete dentition model were mounted on a semi-adjustable articulator. Subsequently, twelve 0.5 mm stainless steel spheres were adhered to reference positions (16, 46, 13, 43, 23, 33, 25, 35, 26, 36, 27, 37) as fiducial markers. Following this, a laboratory scanner generated reference datasets by digitizing the models in maximum intercuspation (MIP). Meanwhile, ten maxillary and mandibular scans were acquired using an intraoral scanner, with all nonarticulated scans duplicated four times to ensure data consistency. Forty VOR intraoral scans were performed in MIP using four registration protocols: left-side, right-side, anterior, and bilateral registration ( n=10 per group), randomized via a computer-generated pseudo-random sequence. For measurement, linear distances (D16-46, D13-43, D23-33, D25-35, D26-36, D27-37, D16-46 represented the single-tooth defect position, whereas D25-35, D26-36, D27-37 reflected positions in free-end edentulism areas) between opposing markers were measured in a reverse engineering software, with deviations (ΔD) from the reference scan calculated to assess accuracy. Specifically, negative ΔD values indicated vertical dimension underestimation. Given that non-normally distributed data were analyzed using medians [interquartile ranges (IQR)], trueness (median ΔD) and precision (IQR) were evaluated. The interaction effect between the registration method and the position of the measurement items was evaluated by using the generalized linear model. The accuracy was compared overall by the Kruskal-Wallis test with the two-sided significance level of α=0.05. For pairwise comparisons, post-hoc tests were conducted by Dunn′s t-test with the Bonferroni correction for the significance level. Results:The accuracy of VOR was affected by registration method ( P<0.05), with a significant position×registration method interaction observed ( P<0.05). In particular, in all four groups, only the bilateral registration group showed trueness of less than 0.1 mm for both free-end edentulism and the single tooth defect, with ΔD16-46, ΔD25-35, ΔD26-36, and ΔD27-37 being 0.059 (0.015), -0.082 (0.052), -0.065 (0.032), -0.070 (0.050) mm, respectively. Moreover, trueness in free-end edentulism showed negative values across all groups, with the largest negative deviations observed in the right-side registration group, with ΔD25-35, ΔD26-36 and ΔD27-37 being -0.410 (0.174), -0.442 (0.225), -0.439 (0.262) mm, respectively. Conclusions:In fully digital workflows of implant restorations for mandibular free-end edentulism with multiple missing teeth, registration method critically influences VOR accuracy. While four registration methods exhibited underestimation of occlusal vertical dimension, bilateral registration achieved the highest accuracy.

Objective This study aims to develop a medical patch surface material featuring a microporous polyurethane(PU)membrane and to assess the material's properties and biological performance.The goal is to enhance the clinical applicability of pelvic floor repair patch materials.Methods PU films with a microporous surface were prepared using PU prepolymer foaming technology.The films were produced by optimizing the PU prepolymer isocyanate index(R value)and the relative humidity(RH)of the foaming environment.The surface morphology of the PU microporous films was observed by scanning electron microscopy,and the chemical properties of the PU microporous films,including hydrophilicity,were analyzed using infrared spectroscopy,Raman spectroscopy,and water contact angle measurements.In vitro evaluations included testing the effects of PU microporous film extracts on the proliferation of L929 mouse fibroblasts and observing the adhesion and morphology of these fibroblasts.Additionally,the effect of the PU microporous films on RAW264.7 mouse macrophages was studied.Immune response and tissue regeneration were assessed in vivo using Sprague Dawley(SD)rats.Results The PU films exhibited a well-defined and uniform microporous structure when the R value of PU prepolymer=1.5 and the foaming environment RH=70%.The chemical structure of the PU microporous films was not significantly altered compared to the PU films,with a significantly lower water contact angle([55.7±1.5]°)compared to PU films([69.5±1.7]°)and polypropylene(PP)([104.3±2.5]°),indicating superior hydrophilicity.The extracts from PU microporous films demonstrated good in vitro biocompatibility,promoting the proliferation of L929 mouse fibroblasts.The surface morphology of the PU microporous films facilitated fibroblast adhesion and spreading.The films also inhibited the secretion of tumor necrosis factor-α(TNF-α)and interleukin(IL)-1β by RAW264.7 macrophages while enhancing IL-10 and IL-4 secretion.Compared to 24 hours,after 72 hours of culture,the expression levels of TNF-α and IL-1β were reduced in both the PU film and PU microporous film groups and were significantly lower than those in the PP film group(P＜0.05),with the most notable decreases observed in the PU microporous film group.IL-10 and IL-4 levels increased significantly in the PU microporous film group,surpassing those in the PP film group(P＜0.01),with the most pronounced increase in IL-4.The PU microporous film induced mild inflammation with no significant fibrous capsule formation in vivo.After 60 days of implantation,the film partially degraded,showing extensive collagen fiber growth and muscle formation in its central region.Conclusion The PU microporous film exhibits good hydrophilicity and biocompatibility.Its surface morphology enhances cell adhesion,regulates the function of RAW264.7 macrophages,and promotes tissue repair,offering new insights for the design of pelvic floor repair and reconstruction patch materials.

Objective: To establish a quantitative three-dimensional method based on intraoral scan and apply it to evaluation of the facial soft tissue contour alterations following single immediate implant and immediate provisionalization (IIPP) in central incisor via intraoral scanning. Methods: This study was a prospective clinical study. The trial was conducted at Department of Implantology, Peking University School and Hospital of Stomatology, from January 2016 to September 2017. Twenty-nine eligible consecutive patients (15 women, 14 men) with a mean age of (34.3±12.0) were included and received immediate replacement of the failure maxillary single central incisor. A screw-retained immediate restoration was delivered for each patient. At 6-month follow-up, impression was taken and a screw-retained permanent restoration was performed for each patient. The anterior maxillary region was scanned by an intraoral scanning system at pre-surgery and 1-year follow-up. The Standard Tessellation Language (STL) files were output to a dedicated software and superimposed. Mid-facial recession and gingival zenith symmetry at 1-year follow-up were measured in the digital models. Three-dimensional configurations of the contour change volume were calculated and reconstructed for visual analysis. Furthermore, the following parameters were used to analyze the reconstructed volume: mean contour change in thickness (△d), mesio-distal width (D_W), coronal-apical height (D_H), contour change at 0, 1, 2, 3, 4, 5 mm apical to the free gingival margin on the implant site. Results: Twenty-seven out of twenty-nine enrolled patients were finally available for analysis. At 1-year follow-up, the mid-facial mucosa level at implant site was (0.23±0.39) mm apical to the gingival zenith of the contralateral tooth. In general, a contour collapse was found in every patient. △d, D_W and D_H of the collapsed volume were (0.62±0.22), (11.03±1.74) and (6.82±1.52) mm, respectively. Contour change at 0, 1, 2, 3, 4, 5 mm apical to the free gingival margin on the implant site were (0.54±0.48), (0.87±0.62), (1.03±0.46), (0.96±0.52), (0.90±0.52), (0.89±0.57) mm. Conclusions The described quantitative measurement based on intraoral scan can be an effective method for assessment of soft tissue contour changes. At 1 year following single IIPP treatment in maxillary incisor, free gingival margin is stable, with only mild recession. The mean level of the facial soft tissue contour collapse is 0.62 mm.

Objective: To evaluate the primary clinical outcomes of immediate provisionalization with a monolithic crown utilizing a novel chairside computer aided design and computer aided manufacture (CAD/CAM) workflow for single tooth immediate implant placement. Methods: This pilot study was a prospective within-subjects design. Thirteen consecutive patients were included and diagnosed with untreatable single incisor or premolar with fine general and local anatomical conditions. The trial was conducted at Department of Implantology, Peking University School and Hospital of Stomatology, Beijing, between January 2016 and June 2016. The teeth were extracted atraumatically and implants were immediately placed in the fresh sockets. Two screw-retained interim crowns were fabricated for the same site utilizing different workflows, a monolithic lithium disilicate (LS2) crown produced by CEREC (Sirona, Germany) chairside CAD/CAM system (CER group) and a manually fabricated resin crown utilizing conventional workflow (CONV group) respectively. The patients were blinded to the group allocation of the two interim crowns. After the clinical try-in for both crowns in a randomized sequence, the patients' level of satisfaction was assessed with a virtual analogue scale (VAS) questionnaire. The restorations chosen by patients themselves were seated in the implants by one experienced prosthodontist. The accuracy, aesthetic effect and clinical time consumption of both groups were compared. Statistical analyses were performed with the Wilcoxon signed rank test. Results: All patients were treated with atraumatic tooth extraction, immediate implant placement using flapless surgery and immediate provisionalization in a single visit. The interim crowns of both groups could be fitted with or without slight adjustments. For each patient, the interim crown of CER group was chosen to be seated with a relatively higher VAS result. The white esthetic score (WES) results demonstrated no statistically significant difference between CER group (7.5±1.1) and CONV group (7.9±0.9) (P>0.05). The mean total work time was significantly different resulting in (131.9±5.0) min for CER group and (205.2±6.3) min(P<0.05). The major difference lied in the laboratory work time, resulting in (113.5±6.3) min for CER group which was significantly shorter than (185.6±6.6) min for CONV group. As for impression taking time, the CER group (7.5±0.8) min was significantly shorter than CONV group (11.7± 1.1) min (P<0.05). However, analysis for clinical adjustment time showed a significantly longer time for CER group [(11.0±2.1) min vs (8.0±2.8) min, P<0.05]. After 3-6 months of observation, the overall survival rate was 100%. Screw loosening occurred in 4 patients and was tightened again. No other major complication soccurred. Conclusions The full digital workflow utilizing CEREC chairside CAD/CAM system to fabricate interim crowns after immediate implant placement in one single visit was feasible. It was more time-efficient and could effectively shorten the laboratory work time compared to the conventional workflow. Patients demonstrated high satisfaction and there was no statistical difference in WES results compared to the conventional workflow. Favorable clinical outcomes were gained in this short-term follow-up study.

Dental Alloys ; Dental Implants ; Dental Materials ; Dental Prosthesis Design ; trends ; Humans ; Zirconium

To investigate the effect of NVP-DPP728, a DPP-Ⅳ inhibitor on new-onset diabetes and the autoimmune response in non-obese diabetic ( NOD ) mice. Diabetes could be reversed in 75% of NVP-DPP728 treated 20 NOD mice. In these 15 mice with remission, insulitis scores were significantly lower than those of the control group. The percentage of Tregs was increased in the thymus and celiac lymph nodes, plasma TGF-β1 and GLP-1 were also significantly increased ( P＜0. 01 ). NVP-DPP728 treatment may reverse new-onset diabetes in NOD mice by reducing insulitis and increasing Tregs.

Objective To investigate the protective effects of α-1 antitrypsin on human islets injured by protease released from pancreas exocrine cells. Methods ( 1 ) in vivo experiment. Parts of the cadaveric pancreas was digested with collagenase, islets were selected artificially, and pancreatic exocrine cells were collected. 8-9 weeks olds male BALB/c-Nu nude mice were induced into diabetic mice with STZ (240 mg/kg body weight, i. p) and randomly divided into two groups: the control group (n = 6), 250 islets were transplanted into left kidney subcapsule of diabetic nude mice; cotransplant group (n = 7), 250 islets and the equal volume of pancreatic exocrine cells were transplanted into different regions of left kidney subcapsule. Blood glucose level was monitored. Nephrectomies were performed after 28 days. The expression of anti-amylase antibodies in subcapsule was detected by using immunohistochemical staining. (2) Islets culture: Three groups were randomly set up. Group 1: purified islet group, 250 islets were incubated into a 6-well culture plate; Group 2: non-purified islet group, 250 purified islets and equal volume of exocrine cells were incubated; Group 3: nonpurified islet + Al AT group, 250 purified islets and equal volume of exocrine cells were incubated with α-1 antitrypsin added (0. 5 mg/ml). After 48 h, insulin content of islets in each well and trypsin concentration in the supernatant of each well were measured. Results 10000 islets were collected.After islets transplantation, the blood glucose levels in control and co-transplant groups were normal,but a delayed islet function in reversing diabetes was in the co-transplant group, and ehe mice in both groups became hyperglycemic after nephrectomy. A large number of anti-amylase antibody-positive cells were found in renal subcapsule in the co-transplant group while little seen in the control group.Insulin levels in the non-purified islet group were decreased as compared with purified islet group,those in the non-purified islet group + A1AT group were higher than in the non-purified islet group,but lower than in the purified islet groups. Trypsin concentration in the non-purified islet group was increased as compared with purified group, that in the non-purified islet group + A1AT group was lower than the non-purified islet group, but higher than in the purified islets group (all P＜0. 01).Conclusion Protease released from acinar cells during pancreatic digestion has detrimental effect on islet function after transplantation. Co-cultivation of islets and pancreatic exocrine cells with A1AT added can prevent islet cell damage caused by trypsin.