Clinical study of age-related sensory innervation of the anterior hard palate / 华西口腔医学杂志

OBJECTIVES@#The present study aimed to explore the innervation of the anterior hard palatine and its relationship with individual development stage. Specifically, the effects of anesthesia on patients of different ages were observed, and neurodevelopment in the maxillofacial region was invesitgated. References that are helpful in selecting local anesthesia were provided.@*METHODS@#A total of 182 patients with mixed dentition were randomly divided into the nasopalatine nerve block and greater palatine nerve block groups. Then, 219 patients with permanent dentition were divided into an adolescent group (13-18 years old) and adult group (over 19 years old), all of whom underwent bilateral greater palatine nerve block. Palatal mucosal pain sensation was tested pre- and post-anesthesia with Von Frey hairs.@*RESULTS@#Among the children with mixed dentition, bilateral greater palatine nerve block tended to result in better anesthetic effects than nasopalatine nerve block (@*CONCLUSIONS@#The sensation of the anterior hard palatine seems mainly dominated by the greater palatine nerve until mixed dentition and gradually shifted to the nasopalatine nerve in conjunction with maxillary development and tooth replacement. Hence, the innervation of the anterior hard palatine induce a secondary development during the development of the maxilla.

Distal-triangular flap design for impacted mandibular third molars: a randomized controlled trial / 华西口腔医学杂志

OBJECTIVES@#This prospective study was performed to evaluate whether the distal-triangular flap was a practical alternative surgical approach for extracting mandibular third molars.@*METHODS@#Sixty participants with impacted mandibular third molars were randomly divided into three groups: group A, distal-triangular flap; group B, Szmyd flap; and group C, envelope flap. The impacted third molars were extracted by the corresponding flapping method. During a three-month follow-up observation after the extraction, the postoperative pain, swelling, mouth opening, and periodontal status were recorded and analyzed by ANOVA and chi-square tests.@*RESULTS@#The 60 participants had successful extraction and 3-month follow-up observation. No participant suffered from postoperative infections, lower lip disorder, or tongue sensory disorders. No statistical differences were found in the postoperative symptoms and signs of the three flap designs, such as postoperative pain, swelling, mouth opening, and periodontal status (@*CONCLUSIONS@#The distal-triangular flap was as safe and reliable as the Szmyd and envelope flaps but more advantageous because of its convenient operative field exposure and low requirement for the patient's mouth opening. Thus, the distal-triangular flap is one of the alternative flap options for extracting impacted mandibular third molars.

Prognosis of teeth with external root resorption caused by adjacent impacted teeth / 华西口腔医学杂志

OBJECTIVE@#This study aimed to investigate the prognosis of permanent teeth with external root resorption (ERR) caused by adjacent impacted teeth.@*METHODS@#A total of 75 ERR teeth (permanent teeth) caused by adjacent impacted teeth of 63 patients were included. The prognosis of ERR teeth was analyzed followed by minimally invasive extraction of the adjacent impacted teeth. The time of follow-up was six months. The relationship between prognosis of ERR teeth and patients' age, gender, root number, type of root resorption and degree of root resorption were analyzed.@*RESULTS@#In the 75 ERR teeth, 67 teeth (89.3%) did not show pulpitis symptoms. The clinical outcome was found to be related with age (r=0.330, P0.05). Pulpitis symptom was not found in ERR teeth of patients under 30 years old.@*CONCLUSIONS@#For ERR teeth caused by adjacent impacted teeth, keeping the pulp vital after surgical removal of impacted teeth is highly probable. Post-operative follow-up instead of preventive root canal therapy of ERR teeth is recommended.

Research progress on the modification of guided bone regeneration membranes / 华西口腔医学杂志

Guided bone regeneration (GBR) is an important technique to solve bone defect problems. In this technique, GBR barrier membranes play an irreplaceable role. GBR membranes can act as a barrier protecting fibroblasts from bone defects and promote osteoblast adhesion and proliferation, leading to bone regeneration. GBR barrier membranes should be enhanced because of the disadvantages of collagen membranes, which are extensively applied to the field of GBR. Therefore, various efforts have been devoted to modifying the antibacterial and osteogenic properties of GBR barrier membranes and developing novel materials. This article reviews the research advancements on the modification of GBR barrier membranes and discover future directions for the development of GBR barrier membranes to provide a reference for bone tissue engi-neering and repair.

Relationship between initial archwire materials and pain at the initial stage of orthodontic treatment: a systematic review and network Meta-analysis / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This review aims to assess the relationship between initial archwire materials and pain at the initial stage of orthodontic treatment.</p><p><b>METHODS</b>On October 1, 2017, seven databases were searched electronically for studies oninitial archwire materials and pain at the initial stage of orthodontic treatment. Quality assessment was performed with bias risk assessment tools suggested by Cochrane's handbook. Data extraction of included studies was also carried out. Network Meta-
analysis was conducted using R 3.4.2 (with JAGS 4.3.0), GeMTC 0.14.3, and STATA 11.0.</p><p><b>RESULTS</b>Five studies with 330 participants were included, comparing four different materials: multi-stranded stainless steel, conventional nickel-titanium, super-elastic nickel-titanium, and thermal heat-activated nickel-titanium. Two studies were at low risk of bias, one was at high risk of bias, and the remaining two were at unclear risk of bias. Network Meta-analysis results showed no statistical differences of pain among the four initial archwire materials at day 1 and day 7. However, the most painless material was most likely to be thermal heat-activated nickel-titanium on rank probability.</p><p><b>CONCLUSIONS</b>On statistical probability, thermal heat-activated nickel-titanium initial arch wires is most likely to cause the least pain at the initial stage of orthodontic treatment, compared with other materials.</p>

Primary tumor prevalence has an impact on the constituent ratio of metastases to the jaw but not on metastatic sites / 国际口腔科学杂志·英文版

This article provides an overview of metastases to jaws (MJ), mainly concerning the differences between American and Chinese patients, and exploring the relationship between the primary tumors' prevalence (PTP) and constituent ratio of MJ. Information concerning of 399 MJ cases in 215 papers, including one new case in our hospital, was subjected to statistic analysis. The main clinical features of MJ, such as constituent ratio of PTP and that of MJ, metastatic sites, treatments, and prognosis were summarized. Breast, lung, kidney, prostate and thyroid (in descending order) were the leading primary sites of MJ. Furthermore, the constituent ratio of MJ was found to be correlated with that of PTP in all subjects including American and Chinese subjects in our study. As to metastatic sites in the mandible, a specific "M" shaped pattern appeared regardless of the tumor type or constituent ratios of MJ were in all subjects. Almost all subjects received traditionally palliative treatments, and the prognosis was quite poor. The PTP had a significant impact on the constituent ratio of MJ. However, it was the properties of the microenvironment rather than characteristics or constituent ratios of tumor cells, that decided the metastatic sites in various tumor subjects.

An experimental study on angiogenesis of non-vascularized autogenous bone graft with vascular bundle implantation / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of vascular bundle implantation in autogenous bone graft on angiogenesis.</p><p><b>METHODS</b>Thirty-six New Zealand white rabbits were evaluated in this study. A portion of bilateral radial bones of a rabbit were removed as free bone grafts, whose periostea were peeled off. In test group, the external maxillary artery bundle was passed through the marrow cavity of the bone. In control group, there was no vascular bundle implantation. Each bone was placed in masseter muscle separately. The rabbits were sacrificed and the specimens were procured at 3 days, 1, 2, 3, 4 and 6 weeks after surgery for histological observation, Chinese ink perfusion and CD34 immunohistochemistry. Microvessel density (MVD) was assessed in order to evaluate angiogenesis of autogenous bone grafts.</p><p><b>RESULTS</b>The bone grafts were found revascularization in 3 days after surgery in the test group, whereas at 2 weeks in the control group. In 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks after surgery, the MVD of test group was significantly higher than that of control group. In 4 weeks after surgery, angiogenesis of test group reached to peak.</p><p><b>CONCLUSION</b>Vascular bundle implantation improved angiogenesis in non-vascularized autogenous bone graft in this study.</p>

Effect of mechanical stimulation on the expression of E-cadherin/cateninin complex in salivary adenoid cystic carcinoma / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of cyclic biaxial mechanical stimulation on adhesion of salivary adenoid cystic carcinoma(SACC) extracellular matrix (ECM) and expression of E-cadherin/cateninin complex in the SACC high metastasis cell lines ACC-M, SACC low metastasis cells line ACC-2, we observed the functions of mechanical stimulation in the adhesion of SACC cell-ECM and investigate the mechanism in the adhesion of ACC.</p><p><b>METHODS</b>Mechanical stimulation were applied to the cells for periods of 1, 3 and 6 hours every day, lasting for 2 days. The amplitude of mechanical stimulation applied to the cells were 1000, 4000 micro strain, at a frequency of 3 Hz. Unstrained cells were used as control. The expression of E-cadherin/cateninin complex on the cell of ACC-M, ACC-2 were studied with laser scanning confocal microscope and image analysis. SACC cell-ECM adhesion was assayed by MTT technique.</p><p><b>RESULTS</b>The results showed that expressions of alpha, beta, gamma-cateninin on the cell of ACC-2 were obviously higher than that ACC-M and E-cadherin on the cell of ACC-M were obviously higher than that ACC-2 without mechanical stimulation. Mechanical stimulation can change the expression of E-cadherin/cateninin complex on the cell of ACC-2 and ACC-M with time. The results also showed that cell-ECM adhesion on the cell of ACC-2 were obviously higher than that of ACC-M without mechanical stimulation. Mechanical stimulation can change the cell-ECM adhesion of ACC-2 and ACC-M with time.</p><p><b>CONCLUSION</b>Mechanical stimulation can change the adhesion of the SACC cell-ECM and expression of E-cadherin/cateninin complex of the SACC cell. We think it played an important role in metastasis of the cancer.</p>

Cancer stem cells: its existence, proliferation and differentiation in an adenoid cystic carcinoma cell line / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the evidences of the presence of tumor stem cells and its impact on the tumorigenesis of adenoid cystic carcinoma cell (ACC)-2 cell line by analyzing the biologic characteristics of different sub-clones of adenoid cystic carcinoma cell line.</p><p><b>METHODS</b>In vitro individual cell culture was employed to observe the proliferating character of ACC-2 cells. The expression of CD44(+) and CD24(-) of ACC-2 cells were investigated by immunohistochemical. Immunomagnetic isolation of different phenotype of ACC-2 cells, followed by cell culture, was used to study the proliferating abilities of different clusters of the cell line. The hetero-transplanted tumor mold was established using BALB/C nude mice by subcutaneous injection of tumor cells. The tumorigenic and differentiating properties of the different cluster were investigated.</p><p><b>RESULTS</b>Only 4.41% of cultured ACC-2 cell had ability of division, proliferation and establishment of cell clone. CD44(+)-CD24(-) cluster accounted for about 8.1% of total ACC-2 cells, among which, 25.71% cells could divide and proliferate. All of CD44 and CD44(+)-CD24(+) cells were failure to be eternal alive in the condition of in vitro individual cell culture. According to the results of in vivo tumorigenic study, the minimal cell quantity to develop a subcutaneous transplanted tumor by CD44(+)-CD24(-) cells was 1 x 10(3), where as the needed cell amount were 1 x 10(5) and 1 x 10(4) as to non-isolated ACC-2 cells and CD44(+) cells, respectively. The CD44(-) and CD44(+)-CD24(+) did not develop transplanted tumors. CD44(+)-CD24(-) ACC-2 cell could differentiate into cells of other phenotypes.</p><p><b>CONCLUSIONS</b>CD44(+)-CD24(-) ACC-2 cells consist of a very small portion of all ACC-2 cells (about 4%). They have remarkable proliferating ability and can bear special phenotypes, The tumorogenic ability of CD44(+)-CD24(-) cells are stronger than that of CD44(+) and non-isolated ACC-2 cells. Eliminating of this cluster from ACC-2 would actually deprive the tumorogenic ability of the cell line.</p>