Objective:To compare the accuracy of intraoral scanning for complete-arch implant-supported fixed prosthesis using umbrella scan bodies (USB) and conventional scan bodies (CSB), providing a reference for the clinical application of umbrella-shaped scanning bodies.Methods:A new type of umbrella-shaped scanning body and its matching auxiliary bar were independently developed. A maxillary type Ⅳ dental stone model with six parallel implant abutment analogs was fabricated. Conventional scanning bodies were installed on the model, and a laboratory scanner was used to scan the model as reference data. The CSB, USB, and USB combined with an auxiliary bar (U+SB) were installed on the model, respectively. A single attending physician performed intraoral scanning 10 times for each group using an intraoral scanner, serving as test group data (CSB, USB, U+SB). The test data were best-fit aligned with the virtual abutment models generated from the reference data. The trueness and precision of root-mean-square error (RMSE) values, inter-abutment distance deviations, angular deviations, and scanning time were measured and calculated. Repeated measures ANOVA and generalized estimating equation models were used for statistical analysis.Results:The trueness of RMSE values [(48.0±12.6) and (45.9±13.4) μm] and distance deviations [(64.5±60.2) and (63.8±54.4) μm] of the USB and U+SB groups were significantly better than those of the CSB group [(81.9±23.9) and (90.0±85.2) μm] (all P<0.05). There was no significant difference in trueness of RMSE values and distance deviations between the USB group and U+SB group (all P>0.05). There were no significant differences in the precision of RMSE values and angular deviations among the three groups (all P>0.05). The scanning time of the USB group and U+SB group [(54.3±11.8) and (35.8±10.1) s] was significantly shorter than that of CSB group [(108.7±38.9) s] (all P<0.05). Conclusions:Compared with conventional scanning bodies, the new umbrella-shaped scanning body demonstrates higher accuracy and efficiency for intraoral scanning impressions in complete-arch implant-supported fixed prosthesis.

Objective:To compare the accuracy of intraoral scanning for complete-arch implant-supported fixed prosthesis using umbrella scan bodies (USB) and conventional scan bodies (CSB), providing a reference for the clinical application of umbrella-shaped scanning bodies.Methods:A new type of umbrella-shaped scanning body and its matching auxiliary bar were independently developed. A maxillary type Ⅳ dental stone model with six parallel implant abutment analogs was fabricated. Conventional scanning bodies were installed on the model, and a laboratory scanner was used to scan the model as reference data. The CSB, USB, and USB combined with an auxiliary bar (U+SB) were installed on the model, respectively. A single attending physician performed intraoral scanning 10 times for each group using an intraoral scanner, serving as test group data (CSB, USB, U+SB). The test data were best-fit aligned with the virtual abutment models generated from the reference data. The trueness and precision of root-mean-square error (RMSE) values, inter-abutment distance deviations, angular deviations, and scanning time were measured and calculated. Repeated measures ANOVA and generalized estimating equation models were used for statistical analysis.Results:The trueness of RMSE values [(48.0±12.6) and (45.9±13.4) μm] and distance deviations [(64.5±60.2) and (63.8±54.4) μm] of the USB and U+SB groups were significantly better than those of the CSB group [(81.9±23.9) and (90.0±85.2) μm] (all P<0.05). There was no significant difference in trueness of RMSE values and distance deviations between the USB group and U+SB group (all P>0.05). There were no significant differences in the precision of RMSE values and angular deviations among the three groups (all P>0.05). The scanning time of the USB group and U+SB group [(54.3±11.8) and (35.8±10.1) s] was significantly shorter than that of CSB group [(108.7±38.9) s] (all P<0.05). Conclusions:Compared with conventional scanning bodies, the new umbrella-shaped scanning body demonstrates higher accuracy and efficiency for intraoral scanning impressions in complete-arch implant-supported fixed prosthesis.

Machine vision image processing technology is extensively employed in the medical realm, particularly in dynamic navigation and robotic systems for oral implantology. It plays a pivotal role in assisting clinicians with precise implant placements, enhancing the predictability of implant restorations. The fundamental principles of machine vision image processing technology utilized in dynamic navigation and robotic systems for oral implantology primarily encompass spatial positioning and registration. However, due to variations in technical principles among different systems, their workflows and technical nuances exhibit distinctive characteristics. Therefore, commencing from the principles of spatial positioning and registration in machine vision image processing technology. This article delves into the current application landscape of machine vision in dynamic navigation and robotics for oral implantology. Its objective is to furnish valuable insights for the clinical implementation of machine vision-assisted implant technology.

Peri-implant soft tissue recession may cause biological and aesthetic complications. Establishing and maintaining sufficient soft tissue around the implant is the basis for achieving long-term stability of implant restoration. This article reviews the research progress on the common causes, surgical treatment indications and techniques of peri-implant soft tissue recession. Available studies indicate that the subepithelial connective tissue graft can result in predictable outcomes when the peri-implant soft tissue recession is sallow.

OBJECTIVETo explore the clinical features and survival of patients with CD56 expression in de- novo acute myeloid leukemia（AML）with t（8;21). .

METHODSClinical data of 82 de novo AML with t（8;21）who were newly diagnosed from Jan 2008 to Apr 2014 were analyzed retrospectively, 50 expressed CD56 and 32 not. Clinical characteristics and prognoses were compared between patients expressing and nonexpressing CD56.

RESULTSThere were no statistically significant differences in terms of age, gender, white blood cell count（WBC）, percentage of bone marrow blasts, extramedullary infiltration rate, the early mortality or the presence of additional cytogenetic abnormalities between CD56 + and CD56- groups（P＞0.05). The expressions of lymphatic antigens CD19 between CD56 + and CD56- groups showed significant difference （30.0% vs 53.1% , P=0.036). The complete remission and 3-year overall survival（OS）showed no significant differences between CD56+ and CD56-groups, while 3- year disease- free survival（DFS）showed significant differences（25.8% vs 46.9%, P=0.014). Multivariable analysis for DFS identified CD56 positivity as an independent predictor. DFS of who received allogeneic hematopoietic stem cell transplantation（HSCT）was better than those treated with intermediate- dose cytarabine/high dose cytarabine（IDAC）as postremission therapy.

CONCLUSIONThe expression of CD56 in de-novo AML with t（8;21) appeared to be associated with poorer prognosis.

Bone Marrow ; CD56 Antigen ; Chromosome Aberrations ; Chromosomes, Human, Pair 21 ; Chromosomes, Human, Pair 8 ; Cytarabine ; Disease-Free Survival ; Hematopoietic Stem Cell Transplantation ; Humans ; Leukemia, Myeloid, Acute ; Prognosis ; Remission Induction ; Retrospective Studies ; Survival Analysis

Objective To observe the effect of early rehabilitation treatment at different time point on the motor function and activity of daily living (ADL) and emotion in acute stroke patients. Methods 120 patients with acute stroke were randomly assigned to three reha-bilitation groups and one control group according to the disease course (3 days, 5 days, 8 days when the disease is steady). Each group con-sisted of 30 eases. The patients in each group were treated with the regular medication therapy, rehabilitation groups were treated with com-prehensive rehabilitation treatment including Bobath technique therapy. Neurological deficit, motor function, balance function, ADL, emo-tion of all the patients were assessed before and 21 days after rehabilitation intervention. Results After treatment, the motor function, bal-ance function, ADL and emotion of each rehabilitation group were improved. The patients'rehabilitation scores in FMA, Fugl-Meyer balance function, MBI and HRSD got much better than that in control group. The difference was statistic significant. The effect of rehabilitation treat-ment did not show difference among rehabilitation groups. Conclusion Early rehabilitation treatment for acute stroke does benefit for stroke patients. Effect does not show vary with the start time of rehabilitation treatment within 8 days after acute stroke.