[Application of ß-TCP for bone defect restore after the mandibular third molars extraction: A splitmouth clinical trial].

OBJECTIVE: To evaluate the effect of bone defect regeneration and the periodontal status of the second molars after mandibular third molars extraction using ß-tertiary calcium phosphate (ß-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 ß-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.

[Applicational evaluation of split tooth extractions of upper molars using piezosurgery].

OBJECTIVE: To evaluate the efficacy of Piezosurgery in split teeth extractions. METHODS: A single-center, randomized, split-mouth study was performed using a consecutive serious of unrelated healthy patients attending the departing of oral and maxillofacial surgery, Peking University School and Hospital of Stomatology. 40 patients were selected for extraction of maxillary molars without reservation value,splitting or nonvital teeth. They were divided into control (20 patients) and test groups (20 patients) randomly. Surgical treatments for both groups were under local anesthesia. Molar teeth of control group were extracted by common equipments like dental elevators, chisels, forceps, etc. While molar teeth of experimental group were extracted by Piezosurgery, aided with the use of common equipments if needed. Then we compared the duration of surgery, frequency of the usage of chisels, expansion of postoperative bony socket surgical discomfort and postoperative pain between two groups. RESULTS: The average of operation time was (629.5±171.0) s in control group and (456.0±337.2) s in test group. The buccal alveolar bone reduced (1.07±0.64) mm in control group and (1.49±0.61) mm in test group. There was a significant difference between the two groups (P<0.05). The duration of surgery for experimental group was significantly longer than that of the control group, but the change of buccal alveolar bone was lower than the control group. For visual analogue scale (VAS) value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference between the two groups (P>0.05). CONCLUSION: Piezosugery can be better to preserve alveolar bone, reduce trauma and patient's fear. Application of the piezosugery reflect the characteristics of minimally invasive extraction, which has the value of promotion. The Piezosurgery technique have the advantage of reducing change of buccal alveolar bone during the surgery, but a longer surgical time was required when compared with the conventional technique. VAS value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference. Minimally invasive tooth extraction technique has good clinical results and high satisfaction. Piezosurgery proved its worth as the instrument adapted to limiting the destruction of bone tissue.

[Applicational evaluation of split tooth extractions of upper molars using piezosurgery].

OBJECTIVE: To evaluate the efficacy of Piezosurgery in split teeth extractions. METHODS: A single-center, randomized, split-mouth study was performed using a consecutive serious of unrelated healthy patients attending the departing of oral and maxillofacial surgery, Peking University School and Hospital of Stomatology. 40 patients were selected for extraction of maxillary molars without reservation value,splitting or nonvital teeth. They were divided into control (20 patients) and test groups (20 patients) randomly. Surgical treatments for both groups were under local anesthesia. Molar teeth of control group were extracted by common equipments like dental elevators, chisels, forceps, etc. While molar teeth of experimental group were extracted by Piezosurgery, aided with the use of common equipments if needed. Then we compared the duration of surgery, frequency of the usage of chisels, expansion of postoperative bony socket surgical discomfort and postoperative pain between two groups. RESULTS: The average of operation time was (629.5±171.0) s in control group and (456.0±337.2) s in test group. The buccal alveolar bone reduced (1.07±0.64) mm in control group and (1.49±0.61) mm in test group. There was a significant difference between the two groups (P<0.05). The duration of surgery for experimental group was significantly longer than that of the control group, but the change of buccal alveolar bone was lower than the control group. For visual analogue scale (VAS) value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference between the two groups (P>0.05). CONCLUSION: Piezosugery can be better to preserve alveolar bone, reduce trauma and patient's fear. Application of the piezosugery reflect the characteristics of minimally invasive extraction, which has the value of promotion. The Piezosurgery technique have the advantage of reducing change of buccal alveolar bone during the surgery, but a longer surgical time was required when compared with the conventional technique. VAS value of surgical discomfort, expansion of postoperative bony socket and the operative fear rate, there were no significant difference. Minimally invasive tooth extraction technique has good clinical results and high satisfaction. Piezosurgery proved its worth as the instrument adapted to limiting the destruction of bone tissue.

[Correlation analysis of pre-operative glucose control targets and tooth extraction prognosis in elderly diabetic patients].

Objective: To evaluate the prognosis of tooth extraction in elderly mellitus patients with fasting plasma glucose (FPG)>8.88 mmol/L and ≤10.00 mmol/L. Methods: This study was a prospective cohort study. One hundred elderly mellitus patients, 53 males and 47 females, aged 65-95 years old (75.8±8.0), were recruited for tooth extraction at the ECG monitoring out-patient clinic in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from Oct 2018 to Oct 2019. Fifty cases were selected into the observation group with FPG>8.88 mmol/L and ≤10.00 mmol/L before tooth extraction, while the rest 50 cases were in the control group with FPG≤8.88 mmol/L. The levels of glycosylated hemoglobin (HbA1c) of patients were required to be≤8.5% before tooth extraction in both groups. Post-operative pain, swelling, pus discharge, fistula at local sockets and systemic fever were observed 24 h and 1 week after the extraction. The healing of tissues around the extraction socket was observed 1 month after operation. The correlation between blood glucose control target and the effects of socket healing before and after tooth extraction was analyzed statistically using SPSS 25.0 software. Results: The pre-operative FPG levels of observation group and control group were (6.92±0.99) and (9.88± 0.68) mmol/L, and HbAlc levels were (6.76±0.83)% and (7.69±0.75)%, respectively. There were no significant differences in age, gender, diabetes history, extraction position, gingival index and tooth looseness between the two groups (P>0.05). Ninety-four percent (47/50 in each group) of patients in the two groups healed well within 24 h after the extraction. There were 6 patients, 3 in each of the two groups, complained tolerable post-operative pain in tooth extraction sockets. However, no redness, swelling and pus in the surrounding tissues were observed. There was no statistical difference of socket healing after the extractions between two groups (P>0.05). Conclusions: The pre-operative levels of FPG≤10.00 mmol/L and HbA1c≤8.5% are reasonable creteria for evaluating tooth extraction risk for the elderly diabetic patients.

[Evaluation of the preliminary clinical effect of flap-raising combined with cortical-perforation technique in tooth extraction cases of patients with potential risk of medication-related osteonecrosis of the jaw].

Objective: To evaluate the preliminary clinical effect of flap-raising and cortical-perforation based extraction method in patients with potential risk of medication-related osteonecrosis of the jaw (MRONJ). Methods: Eighteen patients, who needed teeth extraction in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from February 2016 to November 2020, with a history of using anti-resorption/anti-angiogenesis medication were included in this retrospective study. According to the characteristics of the patient's medication history, patients were stratified into three categories, low-dose anti-resorption drug group, high-dose anti-resorption drug group, and high-dose anti-resorption combined with anti-angiogenesis targeted drug group. There were 15 females and 3 males, the average age was 62.4 years (range from 27 to 87 years) old. A total of 31 teeth were indicated for extraction due to chronic infection. The flap-raising and cortical-perforation techniques were used to extract the affected teeth, and the patients were followed up closely. By observing the healing status and swelling degree of the mucosa of tooth extraction sites, whether there was a fistula, pus and bone exposure of jaw bone,the healing of the tooth extraction sites were evaluated. Results: Among the 18 patients, there were 9 cases of osteoporosis and 9 cases of malignant tumors. Classified by medication-using history, 10 cases were treated with low-dose anti-resorption drugs, 5 cases were high-dose anti-resorption drugs, and 3 cases were high-dose anti-resorption drugs combined with anti-angiogenesis drugs. A total of 31 teeth of the patients were extracted by flap-raising and cortical-perforation based extraction method. Thirteen patients completed treatment underwent local anesthesia and five cases were performed under general anesthesia. The shortest follow-up period was 3 months with an average of 13.2 months. Seventeen patients recovered well after the tooth extraction. One patient had the mandible exposed at one extraction site one month after the surgery, resulting in MRONJ. Conclusions: In patients with potential risks of MRONJ, the application of flap-raising and cortical-perforation based teeth extraction method could safely and effectively alleviate the dental inflammation in the oral cavity.

Measurement of acetabular anteversion in developmental dysplasia of the hip in children by two- and three-dimensional computed tomography.

This study assessed the angle of acetabular anteversion (AA) in 66 children with developmental dysplasia of the hip (132 hips: 24 left, 25 right, 17 bilateral and 49 unaffected hips as controls). The AA was measured by two- and three-dimensional computed tomography (2D-CT and 3D-CT). Measurements were taken by three observers and repeated 2 weeks later by one of these observers. Intra- and inter-observer agreement was analysed using the intra-class correlation coefficient. For all hips, the mean AA (+/-SD) measured by 2D-CT versus 3D-CT was statistically significantly different (15.76 +/- 5.23 degrees versus 16.76 +/- 4.43 degrees , respectively). The mean (+/-SD) AA by 3D-CT in unaffected and affected hips was also statistically significantly different (13.92 +/- 3.95 degrees versus 18.44 +/- 3.82 degrees , respectively). A significant positive correlation between age at presentation and AA was found in affected, but not unaffected, hips. The 3D-CT showed better intra- and inter-observer agreement than 2D-CT for assessing AA hence is a more reliable measurement of AA. An increased AA is one component of anatomical abnormalities in developmental dysplasia of the hip and the abnormality appears to worsen with age.

Open reduction and internal fixation for the treatment of fractures of the lateral humeral condyle with an early delayed presentation in children: a radiological and clinical prospective study.

AIMS: The treatment of late presenting fractures of the lateral humeral condyle in children remains controversial. METHODS: We report on the outcome for 16 children who presented with a fracture of the lateral humeral epicondyle at a mean of 7.4 weeks (3 to 15.6) after injury and were treated surgically. RESULTS: The mean follow-up was four years (1.1 to 8.9), at which time the mean age of the patients was 8.7 years (3.2 to 17.8). The mean Dhillon functional score improved from 3.3 to 5.6 and the mean overall scores improved from 5.6 to 8.5. A total of seven patients had a fishtail deformity and eight had partial lateral epiphyseal closure. None had avascular necrosis. MRI showed an abnormal cartilage signal, incongruence of the joint surface and partial premature closure of the lateral physis in four patients. DISCUSSION: Neither age at the time of injury, the time interval between injury and operation, nor the pre-operative function were correlated with the incidence of complications. These results support the use of internal fixation for children with a lateral humeral epicondylar fracture with a delayed presentation. TAKE HOME MESSAGE: Open reduction and internal fixation yielded a satisfactory outcome within 16 weeks in children with a lateral humeral epicondylar fracture with a delayed presentation.

Clear cell odontogenic carcinoma: a clinicopathologic and immunocytochemical study of 5 cases.

CONTEXT: Odontogenic tumor composed predominantly of clear cells is a rare neoplasm of the jaws that was initially designated as clear cell odontogenic tumor. Subsequent reports in the literature, however, all have indicated that this tumor exhibits an aggressive behavior characterized by infiltrative local growth, recurrence, or metastases. OBJECTIVE: To ascertain the clinicomorphologic features and biologic behavior of this tumor group, we present 5 additional cases using the term clear cell odontogenic carcinoma. DESIGN: Histologic and immunohistochemical examinations were performed on clear cell odontogenic carcinomas from 5 patients. Clinical and follow-up data were recorded, and the literature was reviewed. RESULTS: The patients were 1 man and 4 women with an average age of 42.4 years at diagnosis. Three tumors occurred in the mandible and the other 2 in the maxilla. Four of the 5 cases occurred in the anterior or premolar areas of the jaws, appearing as poorly marginated radiolucencies. All cases consisted of islands and sheets of large clear cells and small basaloid cells with scanty eosinophilic cytoplasm, which were separated by thin, mature, fibrous septae. The tumors were unencapsulated and showed aggressive infiltration of the surrounding muscle and perineural tissues. Most of the clear cells contained cytoplasmic glycogen. Immunocytochemically, the tumor cells were positive for pan-keratin, cytokeratin 19, and epithelial membrane antigen, but were negative for vimentin, S100 protein, desmin, smooth muscle actin, human melanoma antigen (HMB-45), and alpha(1)-antichymotrypsin. Follow-up data showed 4 of 5 patients to have multiple local recurrences, and 1 of these 4 had submandibular lymph node metastasis and a fatal outcome due to uncontrollable tumor growth. CONCLUSION: These results suggest that odontogenic clear cell neoplasms are at least low-grade malignancies and should be classified as carcinomas.

The normal centre-edge angle of Wiberg in the Chinese population: a population-based cross-sectional study.

This study was designed to provide normal reference values for the centre-edge angle of Wiberg in the Chinese population by measuring 1494 radiographs according to the criteria of Tönnis. The mean angle was 23.1 degrees (4.7 degrees to 46.4 degrees) in childhood (four to nine years), increasing to 28.9 degrees (6 degrees to 48 degrees) in adolescence (10 to 18 years) and reaching 32.8 degrees (13.7 degrees to 58.8 degrees) in adults. The angle was positively correlated with age, increasing by a mean of 0.78 degrees annually before adulthood and by 0.070 degrees annually in adults. A relative upward tendency after middle age might contribute to degenerative changes. No gender difference was discovered. The change in the angle with age was similar to that observed in other ethnic groups, showing moderate differences in the average of individual age groups, but the ethnic differences are not sufficient to explain the variation of incidence of developmental dysplasia of the hip in different races.

Crystal structure and replacement reaction of coordinated water molecules of the heteropoly compounds of sandwich-type tungstoarsenates.

Six new heteropoly compounds in the [M4(H2O)2(As2W15O56)2]16- series (M = CuII, MnII, CoII, NiII, ZnII, CdII), previously unknown, were synthesized and characterized by means of IR, UV-vis, CV, 183W NMR, TG-DSC, and elemental analyses. The synthetic method used in preparing this type of heteropoly compounds was different from that in preparing the corresponding tungstophosphates in that the starting materials were transition metal chlorides in 1.5 times the stoichiometric amount and the required pH value is lower than 2. The crystal structure of Na16[Cu4(H2O)2(As2W15O56)2].47H2O was solved in triclinic, P1 symmetry, with a = 12.721(3) A, b = 24.516(5) A, c = 26.450(5) A, alpha = 89.90(3) degrees, beta = 77.32(3) degrees, gamma = 89.96(3)degrees, V = 8048(3) A3, Z = 2, and R = 0.0966. This anion is isostructural with the previously reported [Cu4(H2O)2(P2W15O56)2]16-, having a rhombic tetrameric cluster Cu4O16 sandwiched by two trivacant Dawson-Wells anions [As2W15O56]12-. The range of the bond lengths of the equatorial Cu-O bonds is 1.83-2.05 A, while that of the axial Cu-O bonds is 2.30-2.39 A. The distortion of the Cu4O16 cluster is smaller in the As species than in the P species. Two copper atoms in the Cu4O16 cluster are coordinated by water molecules. The replacement reactions of the coordinated water molecules of this series of heteropoly compounds in aqueous solutions and in selected organic solvents are also reported here for the first time. The results show that [Fe(CN)6]4-, [Fe(CN)6]3-, H2NCH2CH2NH2, etc., can replace the coordinated water to form its characteristic color in aqueous solutions, while in organic solvents the coordinated water molecules are lost, leaving unshared coordination positions that can be occupied by some organic ligands such as pyridine, lactic acid, and acetone to restore the octahedral coordination of M2+. The crystallographic morphologies of this series of heteropolyanions after phase transfer are dependent on different transition metal ions present in the central M4O16 clusters although the anions are isostructural with each other.

[Studies on genetic engineering of human insulin-purification and characterization of human proinsulin and insulin].

E. coli DH 5 alpha cells harboring a plasmid pWR 590-BCA 4 for fused human proinsulin production were cultured. The fused human proinsulin was isolated from the fermented cells and then subjected it to cleavage with BrCN. The cleaved product was then converted to crude proinsulin-S-sulfonate using oxidative sulfitolysis. The isolation of human proinsulin-S-sulfonate was accomplished by ion exchange chromatography on QAE-sephadex A-25, followed by gel filtration on sephadex G-50. The purified human proinsulin-S-sulfonate was folded using a disulfide interchange method. The folding mixture was then chromatographed on sephadex G-50 and purified proinsulin was obtained. The proinsulin was then converted to human insulin and C-peptide by a combination cleavage with trypsin and carboxypeptidase B. The total yield of human insulin was about 5 mg/L The Zinc insulin crystals were obtained with amorphous human insulin using citrate method. The amino acid composition N-terminal sequences as well as C-terminal amino acid residues are in agreement with expected results. The hypoglycemic activity of purified human insulin is 26-27 U/mg, as judged by mouse convulsion assay, and the RIA activity is about 99% of that of porcine insulin.

[Synthesis cloning and expressions in E coli of human insulin A and B chain genes].

Human insulin A and B chain genes were designed and synthesized by using a rapid and simple method. The synthesized A and B chain genes were cloned separately. The expression (plasmids) pWR 590-HIA and pWR 590-HIB were constructed, and the two plasmids can direct the synthesis of the approximately 590 amino acid-long truncated beta-galactosidases fused to human insulin A or B chains. The fused A or B chain proteins were isolated from the fermented cells and cleaved with BrCN. The resulting mixtures were sulfonated and the sulfonated A and B chains were purified. Human insulin was obtained by using an A and B chain combination method.

Total synthesis of yeast alanine transfer ribonucleic acid.

By a combination of chemical and enzymatic methods, small oligonucleotides with lengths varying from 2 to 8 nucleotides were synthesized from mononucleotides. The small oligonucleotides were then ligated with T4 RNA ligase into six large oligonucleotides (9 to 19 nucleotides long) which were further ligated to form two half molecules with 35 and 41 nucleotides respectively. Finally, the two synthetic half molecules were annealed and ligated to obtain the whole molecule of yeast alanine tRNA (tRNAAlay). Prior to this, two semi-syntheses were performed, i.e. ligation of the synthetic 5'-half molecule with the natural 3'-half molecule and that of the natural 5'-half molecule with the synthetic 3'-half molecule. Both the semi-synthetic tRNAAlay and the synthetic tRNAAlay occupy the same position as the natural tRNAAlay after electrophoresis on a 20% polyacrylamide gel. They have the same chemical composition (containing 9 modified nucleotides of 7 different species) and structure as the natural tRNAAlay and are biologically active, i.e. accepting and transferring alanine into proteins in a cell-free protein synthesizing system, the accepting activity of the synthetic product is 52-66% of that of the natural tRNAAlay and 91-106% of that of the reconstituted product of the two natural half molecules. The incorporation activity of alanine into proteins of the synthetic 3H-alanine tRNAAlay is 63%, corresponding to 91% of that of the natural tRNAAlay and 115% of that of the reconstituted product of the two natural half molecules. To the best of our knowledge, this is the first time that a natural RNA with biological activity is synthesized.