Role of collagen membrane in modified guided bone regeneration surgery using buccal punch flap approach: A retrospective and radiographical cohort study / 北京大学学报(医学版)

OBJECTIVE@#To investigate whether the placement of absorbable collagen membrane increase the stability of alveolar ridge contour after guided bone regeneration (GBR) using buccal punch flap.@*METHODS@#From June 2019 to June 2023, patients who underwent GBR using buccal punch flap simultaneously with a single implant placement in posterior region (from first premolar to second molar) were divided into coverage group, in which particular bone graft was covered by collagen membrane and non-coverage group. Cone beam CT (CBCT) was taken before surgery (T0), immediately after surgery (T1), and 3-7 months after surgery (T2), and the thickness of the buccal bone plate at different levels (0, 2, 4, and 6 mm) below the smooth-rough interface of the implant (BBT-0, -2, -4, -6) was mea-sured after superimposition of CBCT models using Mimics software.@*RESULTS@#A total of 29 patients, including 15 patients in coverage group and 14 patients in non-coverage group, were investigated in this study. At T0, T1, and T2, there was no significant difference in BBT between the two groups (P>0.05). At T1, BBT-0 was (2.50±0.90) mm in the coverage group and (2.97±1.28) mm in the non-coverage group, with corresponding BBT-2 of (3.65±1.08) mm and (3.58±1.26) mm, respectively. At T2, BBT-0 was (1.22±0.55) mm in the coverage group and (1.70±0.97) mm in the non-coverage group, with corresponding BBT-2 of (2.32±0.94) mm and (2.57±1.26) mm, respectively. From T1 to T2, there were no statistically significant differences in the absolute values [(0.47±0.54)-(1.33±0.75) mm] and percentages [(10.04%±24.81%)-(48.43%±18.32%)] of BBT change between the two groups. The thickness of new bone formation in the buccal bone plate from T0 to T2 ranged from (1.27±1.09) mm to (2.75±2.15) mm with no statistical difference between the two groups at all levels.@*CONCLUSION@#In the short term, the GBR using buccal punch flap with or without collagen membrane coverage can effectively repair the buccal implant bone defect. But collagen membrane coverage showed no additional benefit on alveolar ridge contour stability compared with non-membrane coverage.

Application of β-TCP for bone defect restore after the mandibular third molars extraction: A splitmouth clinical trial / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the effect of bone defect regeneration and the periodontal status of the second molars after mandibular third molars extraction using β-tertiary calcium phosphate (β-TCP) in the test side compared with the spontaneously healed side. To the bone defect of mandibular second molars as a result of surgical removal of impacted mandibular third molars is a common phenomenon, many research shows that the mandibular second molars alveolar bone regeneration was about 1.5 mm and the periodontal pocket >7 mm was greater than 43.3% after mandibular third molars extraction. There has been significant progress researches in the repair of bone defect after the third molar removal, and bone graft filling was one of the effective methods. The bone graft substitutes include autogenous bone, allograft bone, xenograft bone and synthetic bone.@*METHODS@#A split mouth, randomized clinical study was designed. Fifteen patients with mandibular third molars in the same jaw planned to be extracted were enrolled in the study. One of the sockets of each patient was randomly selected and filled with easy-graftTMCLASSIC (test group). The contralateral socket was left to heal spontaneously (control group). cone beam computed tomography (CBCT) scans were performed the day after the extraction and after 6 months. The horizontal dimensional changes of the sockets were recorded. The newly formed bone volume in the bone was analyzed by CBCT, and the probing depth (PD) was recorded. Student's t test was used to evaluate the difference between the two groups for each parameter, and the P value lower than 0.05 was considered to be statistically significant.@*RESULTS@#Fifteen patients (30 sockets) completed the flow-up, and all the 30 sockets healed uneventfully. After 6 months' healing, the new bone volume fraction of the test group was 63.3%±2.2%, while the new bone volume fraction of the control group was 50.1%±1.9%. The vertical dimensional increment of the test group was (5.53±0.39) mm, while the vertical change of the control group was (1.53±0.27) mm. The distal buccal site PD of the second molar was (3.0±0.7) mm in the test group, and (6.5±0.8) mm in the control group. Statistically significant differences were detected between the two groups.@*CONCLUSION@#The randomized controlled clinical trial showed that the application of β-TCP for bone defect repair after the mandibular third molars extraction resulted in more vertical bone regeneration and less probing depth when compared with what was spontaneously healed.

Three-dimensional finite element analysis of Kirschner wire fixation configuration for supracondylar fracture of humerus fracture in children / 中国骨伤

OBJECTIVE@#To establish a new mechanical model of distal humerus in children with epiphysial cartilage, stimulate supracondylar humerus fracture and perform three dimensional finite elements, and study effect of pins numbers, pin tract, outlet height and pin configurations on stability of fixation.@*METHODS@#Three dimensional computed tomography (CT) data of 6-year-old boy with distal humerus was downloaded from picture archiving and communications systems software (PACS), the data of picture was imported into Simpleware and SolidWorks 2016 software to establish distal humerus fracture in children contained ossific nucleus of the capitellum (ONC) and distal cartilage. Normal extense supracondylar humerus fracture model was established to stimulate configurations of crossed and lateral pinning fixation, 30 N was added on the direction of flexion extension and varus valgus, while 50 N was added on the direction of internal and external turning. Stability was analyzed by displacement degree of distal fracture.@*RESULTS@#Among 2-pin configurations, 2-crossed pins were more stable against rotation forces which could resist rotation stress over 2 585 Nmm/ °, while low position through ONC of 2-divergent lateral pins were more stable, which could resist stress of 45 N /mm and 190 N /mm during the test of resistant strains and varus-valgus stress. The third pins was added into the more stable lateral 2-pins, the stability in all directions were increased obviously, and 3 crossed pins is the most stable, stress of flexion-extension, varus-valgus and internal-external turning were 198 N /mm, 395 N /mm and 6 251 Nmm/ °.@*CONCLUSION@#Two-divergent lateral pins could provide enough stability for supracondylar humerus fracture in children. In two-crossed pins, the upper border of MDJ could provide the best stability. Three-crossed pins could offer the best stability against both translation and rotation forces.

Magnetic Resonance Three-dimensional Cube Technique in the Measurement of Piglet Femoral Anteversion / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The accurate measurement of the femoral anteversion (FA) angle is always a topic of much debate in the orthopedic surgery and radiology research. We aimed to explore a new FA measurement method to acquire accurate results without radiation damage using piglet model.</p><p><b>METHODS</b>A total of thirty piglets were assigned to two groups based on the age. Bilateral femora were imaged with 3.0-T magnetic resonance (MR) and 64-slice computed tomography (CT) examinations on all piglets. FA was measured on MR-three-dimensional (3D) postprocessing software with a four-step method: initial validation of the femoral condylar axis, validation of the condylar plane, validation of the femoral neck axis, and line-plane angle measurement of FA. After MR and CT examinations, all piglets were sacrificed and their degree of FA was measured using their excised, dried femora. MR, CT, and dried-femur measurement results were analyzed statistically; MR and CT measurements were compared for accuracy against each other and against the gold standard dried femur measurement.</p><p><b>RESULTS</b>In both groups, the mean FA value measured by MR was lower than that measured by CT. A statistically significant difference was observed between CT- and dried-femur measurements but not between MR- and dried-femur measurements. A higher correlation (0.783 vs. 0.408) and a higher consistency (0.863 vs. 0.578) with dried-femur measurement results were seen for MR measurements than CT measurements in the 1-week age group. However, in the 8-week age group, similar correlations (0.707 vs. 0.669) and consistencies (0.864 vs. 0.821) were observed.</p><p><b>CONCLUSIONS</b>Noninvasive MR-3D-Cube reconstruction was able to accurately measure FA in piglets. Particularly in the 1-week age group with a larger proportion of cartilaginous structures, the correlation and consistency between MR- and dried-femur measurement results were higher than those between CT- and dried-femur measurements, suggesting that MR may be a new useful examination tool for FA-related diseases in children.</p>

Clinical evaluation of influence of aspirin on post-operative bleeding after tooth extraction in the elderly / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of continuation of aspirin before tooth extraction in the elderly.</p><p><b>METHODS</b>The patients enrolled in this study were the elderly requiring a single non-impacted tooth extraction. 300 elderly outpatients used lidocaine local infiltration anesthesia, 200 patients without using aspirin before tooth extraction served as control group I, 100 patients with prolong use of aspirin before tooth extraction as observation group I. 300 elderly outpatients used compound articaine local infiltration anesthesia, 200 patients without using aspirin before tooth extraction served as control group II, 100 patients with prolong use of aspirin before tooth extraction as observation group II.Bleedings at 5, 10, 30 min, 24 h after tooth extraction were observed and the relationship between postoperative bleeding and intake of aspirin was analyzed.</p><p><b>RESULTS</b>There was no significant difference at 5, 10, 30 min, 24 h in postoperative bleeding after extraction between control group I and observation group. The incidence of bleeding of observation group II after tooth extraction at 5 min was higher than that of control group II and there was no significant difference at 10, 30 min, 24 h between the two groups.</p><p><b>CONCLUSIONS</b>Continuation of aspirin have no influence on postoperative bleeding. Therefore we suggest that there was no indication to discontinue aspirin for the elderly before a single non-impacted tooth extraction.</p>

Clinical observation of influence of warfarin on post-operative bleeding after tooth extraction in the elderly / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of continuing warfarin when international normalized ratio (INR) was less than 2.5 before tooth extraction in the elderly.</p><p><b>METHODS</b>One hundred elderly outpatients with prolong use of warfarin and maintaining INR < 2.5 before tooth extraction served as observation group, 200 elderly outpatients without taking anticoagulant and antiplatelet medicine served as control group. All the patients underwent a single non-impacted tooth extraction. Postoperative bleeding at different time was observed.</p><p><b>RESULTS</b>There was significant difference in postoperative bleeding at 5, 10, 30 min, 24 h after extraction and there was no significant difference at 48 h between control group and observation group (P < 0.05) and no bleeding was found in either group at 48 h (incidence of bleeding were 0%).</p><p><b>CONCLUSIONS</b>It was feasible to continue warfarin for the elderly maintaining INR < 2.5 undergoing a single non-impacted tooth extraction by monitoring postoperative bleeding and hemostatic treatment measures.</p>

Developmental changes of acetabular cartilage complex: an experimental study of a straight-leg swaddle model of newborn rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>By establishing a model of straight-leg swaddle of newborn rats and observing the experimental animals'hips morphologically and pathologically, this study explored the changes of gross appearance of the acetabulum and the maturity of cartilage cells in the different regions of acetabular cartilage complex.</p><p><b>METHODS</b>The legs and hips were fixed by adhesive tape for 10 days in the position of hip extension and adduction in 31 newborn Wistar rats (experimental group). The other 31 newborn rats without legs and hips treatment were used as the control group. After 10 days raising in the same condition, all the rats were sacrificed. The gross appearance, histological observations and VEGF and type X collagen immunohistochemistry were used for examining the acetabulum changes.</p><p><b>RESULTS</b>A straight leg swaddle model of newborn rats was established successfully. In the experimental group the acetabulum became shallow and small and surrounded by more soft tissues. There were 49 dislocated hips (49/54) in the experimental group and 2 hips dislocated (2/60) in the control group (p<0.01). Fake acetabulum appeared in the experimental group. In the control group, the shape of the acetabulum was normol, and no fake acetabulum was found. The safranin O-fast green staining showed that the orange-red cartilage in the experimental group was wider than the control group. Immunohistochemistry observations showed VEGF and type X collagen immunoreactivities in the hypertrophic layer of the acetabular cartilage complex in the experimental group were lower than those in the control group. The percentages of VEGF positive and type X collagen positive cells in the iliac hypertrophic layer of the acetabular articular cartilage were significantly higher than those in the ischiadic ramus and the pubic branch in the experimental group.</p><p><b>CONCLUSIONS</b>VEGF and type X collagen immunoreactivities in acetabular cartilage cells decrease in a straight-leg swaddle model of newborn rats. This suggests that this position might lead to dysmaturity of the acetabular cartilage cells and affect the development of the acetabulum.</p>

Expression of COL1a1 and COL3a1 in the capsule of children with developmental dislocation of the hip / 中国当代儿科杂志

<p><b>OBJECTIVE</b>The etiology of developmental dislocation of the hip (DDH) remains uncertain, but some research has shown that this disorder is closely related to hip joint laxity. This study examined the expression of collagens type I and III mRNA and protein in the hip capsule of children with DDH in order to investigate the roles of collagens type I and III in hip joint laxity.</p><p><b>METHODS</b>Nine children with DDH and nine age and gender-matched normal children (control group) were enrolled. Semiquantitative RT-PCR method was used to detect mRNA expression of COL1a1 and COL3a1 in the hip capsule. Western-Blot method was used to detect protein expression of COL1a1 and COL3a1 in the hip capsule. The quantitative analysis of the COL1a1 and COL3a1 was performed by professional image software and the results were analyzed with standard statistical methods.</p><p><b>RESULTS</b>mRNA and protein expression of COL1a1 in the DDH group was significantly lower than that in the control group (P<0.01). Compared with the control group, COL1a3 mRNA expression in the DDH group decreased significantly (P<0.01), but COL1a3 protein expression was not significantly different.</p><p><b>CONCLUSIONS</b>The decreased collagen I mRNA and protein expression in the hip capsule might contribute to hip joint laxity in children with DDH. Collagen type III may not be associated with hip joint laxity in DDH.</p>

The clinical application of acellular dermal matrix to repair the defect of oral mucosa / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical effect of acellular dermal matrix allograft in repairing the defect of oral mucosa.</p><p><b>METHODS</b>Forty-two cases of large superficial defects in oral cavity were repaired by acellular dermal matrix. Defect areas included vestibule, tongue, the floor of mouth, buccal mucosa, palate, gingival and lip. Defect size was between 2.25 cm(2) and 12 cm(2). The basement membrane side of acellular dermal matrix was exposed to oral cavity, and another side was attached to the surgical wound surface. It was fixed by suture, reverse strapping and prepared template to overlaid large superficial defect of oral mucosa. The patients were followed up from 3 months to 1 year after operation.</p><p><b>RESULTS</b>The wounds were completely healed in 40 cases, partially healed in 2 cases. There was no failure case. The healing was divided into two types: epithelialization healing pattern in 12 cases, attached healing pattern in 30 cases. Contraction of grafts occurred at 2 - 4 weeks. The contraction rate was 3.7% +/- 1.1% at fourth week. Scarring did not appear.</p><p><b>CONCLUSION</b>The clinical result of acellular dermal matrix allograft in repair the defect of oral mucosa is good. Acellular dermal matrix can be taken as a substitute to autograft of skin.</p>