Tooth extraction is a common operation in oral surgery. Traditional extraction instruments, such as bone chisel, elevator, and bone hammer, lead to not only severe trauma but also unnecessary complications, and patients easily become nervous and apprehensive if tooth extraction is performed using these violent instruments. In recent years, with the development of minimally invasive concept and technology, various micro-power instruments have been used for tooth extraction. This innovative technology can reduce the iatrogenic trauma and complications of tooth extraction. Additionally, this technology can greatly decrease the patient’s physical and mental pressure. The new equipment compensates for the deficiency of traditional tooth extraction equipment and facilitates the gradual replacement of the latter. Diverse micro-power systems have distinct strengths and weaknesses, so some auxiliary instruments are still needed during tooth extraction. This paper focuses on the various micro-power systems for tooth extraction and tries to compare the advantages and disadvantages of these systems. Selection and usage of auxiliary equipment are also introduced. Thus, this paper provides reference for the proper application of the micro-power systems in tooth extraction.

Objective   This study aimed to investigate the effects of hirudin on the expression of transforming growth factor (TGF-β1) and basic fibroblast growth factor (bFGF) in human gingival fibroblasts (HGFs) in vitro, as well to explore its function in the mechanism of gingival remodeling. Methods  After culturing was performed with classic tissue-explant method, HGFs were derived from normal gingival and gingival hyperplasia tissues followed by orthodontic treatments with different concentrations of hirudin. The mRNA and protein expression levels of TGF-β1 and bFGF were respectively detected by real time quantity polymerase chain reaction and immunocytochemistry. Results   Compared with normal HGFs, TGF-β1 expression promoted collagen synthesis of fibroblasts, whereas bFGF collagen synthesis was decreased in hyperplasia HGFs without hirudin (P<0.05). Hirudin significantly upregulated the expression levels of bFGF but downregulated TGF-β1 in hyperplasia HGFs (P<0.05). Conclusion  Orthodontic force may influence the balance of collagen synthesis and degradation in HGFs. Hirudin may modulate the balance of HGF collagen metabolism, thereby promoting gingival remodeling.

 Objective  This study aims to examine the expression of nuclear factor κB (NF-κB)/B cell lymphoma-2 (Bcl-2) signal pathway and glycogen synthase kinase 3β (GSK-3β) in oral squamous cell carcinoma (OSCC) and provide references for the early diagnosis and prognosis evaluation of OSCC. Methods  A total of 55 cases of OSCC and 10 cases of paracancerous mucosa were examined in this study. Their expressions of GSK-3β, NF-κB and Bcl-2 were detected using the SP method immunohistochemistry. The correlation between their expression in OSCC and the clinical and pathological peculiarity of OSCC was analyzed. Results  The positive expression of GSK-3β, NF-κB, and Bcl-2 in OSCC were significantly higher than that in paracancerous mucosa (P<0.01). The expression of GSK-3β, NF-κB, and Bcl-2 had no obvious relationship with patient’s age, sex, and clinical stages of the disease (P>0.05). The expression of Bcl-2 was significantly correlated with the degree of tumor differentiation (P<0.05), whereas the expression of GSK-3β and NF-κB in OSCC had no obvious relationship with the degree of tumor differentiation (P>0.05). Strong positive correlations were observed among the expressions of GSK-3β, NF-κB, and Bcl-2 (P<0.05). Conclusion  The positive expression of GSK-3β, NF-κB, and Bcl-2 in OSCC are significantly higher than that in paracancerous mucosa. Detecting GSK-3β, NF-κB, and Bcl-2 in OSCC may have implications in the early diagnosis and prognosis evaluation of OSCC.

Objective  This research aims to study the changes in pain threshold and glial cell line-derived neurotrophic factor (GDNF) in a Sprague Dawley (SD) rat model of trigeminal neuralgia. Methods  A total of 36 male SD rats were randomly divided into three groups: operative, sham-operative, and control. In the operative group, a chronic constriction injury (CCI) was caused by placing loose chromic gut ligatures around the right infraorbital nerve (ION). In the sham-operative group, the right ION was subjected to the same procedure, but without ligation. In the control group, the right ION was not subjected to any treatment. The pain thresholds of the three groups were recorded at different times after the operation. The GDNF expression in each group was analyzed via immunohistochemical staining. Results  An allodynia to mechanical stimulation in the region of the ligated ION was observed starting on the 2nd week after operation. Pain thresholds started to increase gradually from the 6th week and returned to the original level at the 10th to 12th week after operation. Cells that expressed the GDNF markedly increased in number in the operative group with changes observed at different times. Conclusion  We use chronic constriction injury to the infraorbital nerve (CCI–ION) to establish a trigeminal neuralgia-like animal model in SD rats. GDNF may play a role in regulating pain by promoting the restoration and regeneration of nerve fibers.

Objective  This study aims to detect microRNA-17(mir-17) expression on the osteogenic differentiation of advanced glycation end products (AGEs)-stimulated hunman periodontal ligament stem cells (HPDLSCs) and to analyze the influence of these cells on this process. Methods  HPDLSCs were isolated using limited dilution technique. After osteogenic differentiation occurred, different time points of mir-17 expression in the experimental groups were detected by real time polymerase chain reaction (PCR). The mir-17 overexpression and inhibition were evaluated using cell transfection technique. Differences in gene expressions were detected by real time PCR; differences in protein expressions were analyzed by Western blot. Results  The mir-17 expression was reduced after osteogenic differentiation occurred at 3, 7, and 14 d compared with that in the control group (P<0.05). The expression levels of bone sialoprotein(BSP), Runt-related transcription factor-2 (Runx-2) and alkaline phosphatase (ALP) in the experimental groups were lower than those in the mimic control group when mir-17 expression increased. In addition, the protein expression levels of Runx-2 in the experimental groups were lower than those in the control group. The expression levels of BSP, Runx-2 and ALP in the experimental groups were higher than those in the inhibitor control group when mir-17 expression decreased. Likewise, the protein expression levels of Runx-2 in the experimental groups were higher than those in the control group. Conclusion  AGEs inhibit the osteogenic differentiation of HPDLSCs by affecting mir-17 expression.

Objective  This study aims to explore the effect of Notch signaling depression on the receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis of RAW264.7 cells. Methods  Mice RAW264.7 cells were cultured and differentiated into osteoclasts with the induction of RANKL. The expressions of Notch1, Notch2, Delta1, Jagged1, Hes1, tartrate-resistant acid phosphatase (TRAP), and Cathepsin K genes during osteoclastogenesis were analyzed using real-time polymerase chain reaction. Osteoclast formation was analyzed using TRAP assay with suppression of Notch receptors by a selective γ-secretase inhibitor (GSI). Results   Notch1, Notch2, Delta1, Jagged1, and Hes1 expressions in RAW264.7 cells were upregulated following 50 ng•mL-1 RANKL stimulation for 3 d, concomitant with the expression of the osteoclast differentiation markers TRAP and Cathepsin K. Notch2 and Jagged1 had the most remarkable increase in the Notch family members. GSI inhibited RANKL-induced osteoclastogenesis of RAW264.7 cells and Hes1 expression dosedependently. Conclusion  Notch signaling activation may promote RANKL-induced osteoclastogenesis of RAW264.7 cells.

 Objective  RNA interference was applied to knockdown the Dhcr7 gene in mouse embryonic palatal shelves to facilitate understanding of the function of Dhcr7 gene variants in the fusion of palatal shelves. Methods  The pAdTrack-CMV-siDhcr7 was constructed using the specific siRNA sequence of Dhcr7 from C57BL/6J mouse. The pAdTrack-CMVsiDhcr7 of positive clones was reconstructed in vitro, and the recombinant adenovirus pAdEasy-1-siDhcr7 of kanamycin resistance was screened. The adenovirus vector DNA was then prepared for transfecting the embryonic palatal shelves. Thirty pairs of embryonic palatal shelves at 13.5 d gestational age were harvested and then randomly divided into the following three groups: normal control group (n=10), which included palatal shelves inculture medium without cholesterol; blank adenovirus control group (n=10), which included palatal shelves in culture medium without cholesterol and blank adenovirus; and experimental group (n=10), which included palatal shelves in culture medium without cholesterol and adenovirus encoding Dhcr7 siRNA. At 48 h after in vitro cultivation, the mRNA and protein of the palatal shelves were obtained for scanning electron microscopy (SEM), reverse transcription polymerase chain reaction (RT-PCR), and Western blot analyses. Results  SEM showed that the palatal shelves of the normal control and blank adenovirus control groups fused and formed continuous palates, whereas those of the experimental group was almost undeveloped but exhibited large gaps between the two palatal shelves.RT-PCR and Western blot analyses showed that the mRNA and protein of Dhcr7 in the experimental group decreased compared with those in the normal control group with a significant difference (P<0.05). Conclusion  Results indicate that Dhcr7 gene silencing affects the fusion of palatal shelves. Thus, Dhcr7 gene may serve a function in the normal development of palates.

Objective  Periodontal tissue remodeling includes remodeling of alveolar bone, periodontal ligament, and cementum. Cementoblast plays a main role in repairing root resorption. Canonical Wnt/β-catenin signaling can promote the odontogenic differentiation in osteoblast. However, the mechanism on how the orthodontic force influences the function of cementoblast and the relationship between the canonical Wnt/β-catenin signaling and Runx2 of cementoblast are not yet known. The aim of this study is focus on this relationship. Methods  OCCM30 cementoblasts were subjected to mechanical strain by four-point bending system with tension stress for 0, 3, 6, and 12 h. They were pretreated with different concentrations of Dikkopf-1 (DKK1) for 48 h. Western blot analysis was performed to detect the β-catenin levels in the nucleus. Runx2 mRNA was observed by real-time quantitative polymerase chain reaction (RT-PCR). OCCM30 cementoblasts were then pretreated with 150 ng•mL-1 DKK1 for 48 h and subjected to mechanical strain by FX4000T system with tension stress for 12 h. Western blot analysis was conducted to detect the β-catenin levels in the nucleus, and Runx2 mRNA was observed by RT-PCR. Results  OCCM30 cementoblasts had significantly higher Runx2 mRNA and β-catenin levels after being loaded with mechanical stress. The amount of Runx2 mRNA in OCCM30 cementoblasts was significantly decreased by DKK1. When OCCM30 cementoblasts were pretreated with DKK1 without stress, their β-catenin level was significantly decreased by DKK1 and Wnt signaling was blocked. When they were not pretreated with stress, the β-catenin level with DKK1 was lower than that without DKK1.Without DKK1, the β-catenin level in OCCM30 cementoblasts increased after being loaded with mechanical stress. With DKK1, the β-catenin level in OCCM30 cementoblasts, which were loaded with mechanical stress, was higher than that without mechanical stress. Conclusion  Cementoblasts had higher Runx2 mRNA expression under mechanical stress because of the Wnt/β-catenin signaling pathway effect.

Objective To assess the diagnostic efficacy of contrast-enhanced CT in diagnosing mandibular invasion of oral cancers. Methods  PubMed, Excerpta Medica Database (EMBASE), the European Grey Literature Database, Chinese Biomedical Literature Database (CBM), and CQVIP were searched electronically on January 03, 2014. Hand-searching was also performed on 19 relevant Chinese journals. The methodological quality assessment, as suggested in Cochrane Handbook, and the data extraction of the studies included were performed by two reviewers in duplicate. Meta-analysis was conducted using the Meta Disc 1.4 software. Results  Fourteen studies that involved 642 participants were included. Among the seven prospective studies, one had a low bias risk and the rest had unclear bias risks. When mandibular invasion was diagnosed the Meta-analysis results showed that the pooled sensitivity (SEN) was 0.718 [95% confidence interval (CI), 0.665-0.767], the pooled specificity (SPE) was 0.909 (95% CI, 0.872–0.938), the area under curve (AUC) was 0.906 1, and the Q* was 0.837 8. When mandibular medullary invasion was diagnosed, the SEN was 0.787 (0.643–0.893), the SPE was 0.904 (0.790–0.968), the AUC was 0.949 6, and the Q* was 0.890 0. The Meta-regression results showed that the smaller slide thickness had a higher diagnosis efficacy. Conclusion CT showed a high efficacy in diagnosing mandibular or medullary invasion caused by oral cancers. With a high SPE, contrast-enhanced CT can confirm the clinical diagnosis of bone invasion effectively. In addition, selecting a smaller slide thickness CT can increase diagnosis efficacy.

Objective  This longitudinal study aimed to investigate the caries status of primary and permanent teeth among 6-year-old children in Sichuan Province from 2010 to 2012. Methods  A sample that comprised 652 6-year-old children from six different elementary schools (three represented the urban areas, and the other three represented the rural areas) were examined according to a baseline, with follow-up examinations at 1, 2, and 3 years. Eruption and caries experience were recorded using World Health Organization criteria. Results  The prevalence rates of primary tooth caries of 6-year-old children in Sichuan Province for 3 years were 74.23% (484/652), 75.61% (493/652), and 81.90% (534/652). The filling rate of the primary teeth was 5.87% (145/2 471) in 2012, with significant differences (P<0.01) between the urban areas [10.84% (133/ 1 227)] and rural areas [0.96% (12/1 244)]. The total pit and fissure rate of the first molar was 14.11% (92/652) in 2012, with significant differences between the two areas (P<0.01) [rural:0.66% (2/303); urban:25.79% (90/349)]. Conclusion  The prevalence of caries in the primary and permanent teeth of 6-year-old children was high. An increasing prevalence tendency was observed as the age increased. The prevalence of first molar caries indicated that prevention and control of dental caries should be performed as early as possible.

Objective  To evaluate the effect of repeated sintering on the color and translucency of dental lithium disilicatebased glass ceramic. Methods  Thirty disc specimens (10 mm in diameter, and 1.00 mm±0.01 mm in thickness) were fabricated using an IPS e.max Press HT A2 ingot and then randomly divided into six groups (S0, S1, S2, S3, S4, and S5) (n=5). Each group was sintered 0, 1, 2, 3, 4, and 5 times individually according to the manufacturer’s recommendation. After polishing, ultrasonic cleaning, and drying, the color parameters (L*, a*, and b* values) and transmittance (τ) of all the specimens were measured using a ShadeEye NCC dental colorimeter and a TM-2 spectrophotometer, respectively. Subsequently, C*ab and ΔE were calculated. The results were statistically analyzed using SPSS 17.0 software for ANOVA and LSD. Results  After repeated sintering, the L* value significantly decreased (P<0.05), and the a*, b*, and C*ab values initially increased and then decreased (P<0.05). The color parameters (L*, a*, and b*) and the C*ab values of group S3 were higher than those of the other groups. The τ values initially increased and then decreased (P<0.05), and these values were optimal when sintered twice. In terms of transmittance (τ), statistical differences existed between the following groups: S0 and S2, S0 and S3, S2 and S5, and S3 and S5 (P<0.05). Compared with group S0, the color differences ΔE were 0.89 minimally and 2.01 maximally after different sintering times, which can be clinically acceptable. Conclusion  Repeated sintering can affect the color and translucency of the IPS e.max Press lithium disilicate-based glass ceramic, but the color difference can be clinically acceptable.

 Objective  This study aims to investigate the caries status of the first permanent molar and primary tooth among 7-to 9-year-old children in Tangshan city and the correlation between caries of primary tooth and the first permanent molar. Methods  A stratified cluster sampling method was used on the basis of the Basic Approach of Oral Health Survey of WHO and the Guideline of the Third National Oral Health Survey. A total of 10 primary schools were randomly sampled in clusters that included 51 primary school sampling spots in Tangshan. The caries status of 1 794 children aged 7 years to 9 years was examined. Results  The prevalence rate of the first permanent molar caries was 47.49% (852/1 794), the mean number of DMFT was 1.30±1.59, the mean number of DMFS was 1.96±3.40, and the filling rate was only 2.35% (20/852). The prevalence rate and mean DMFT of the first permanent molar caries showed significant difference between different ages and genders (P<0.05). However, the mean DMFS of the first permanent molar caries only showed significant difference between the various ages (P<0.05). The prevalence rate of the primary tooth caries was 83.11% (1 491/1 794), the mean number of dmft was 4.82±3.55, the mean number of dmfs was 6.51±5.61, and the filling rate was 12.41% (185/1 491). Caries of primary tooth was the first permanent molar caries risk factor [r=0.277, OR=5.736, P=0.00, 95%CI (4.175, 7.881)]. Significant correlation was found between the caries of primary tooth and first permanent molar (r=0.274, P<0.001). Conclusion Caries status of the first permanent molar among 7-to 9-year-old children in Tangshan city is serious. Caries status of primary tooth may play an important role in predicting the first permanent molar caries in clinic and prevention.

Objective  We aims to evaluate the therapeutic effect of maxillary protraction on maxillary maldevelopment using Coben analysis to illustrate the advantages of Coben analysis in identifying pathogenic mechanisms and in designing treatment plans for Class Ⅲ malocclusions. Methods  A total of 120 patients were diagnosed to have skeletal Class Ⅲ malocclusions with maxillary maldevelopment. These patients were selected as the subjects of the present research. Maxillary protraction was exerted to promote maxilla growth. Cephalometric analysis was conducted by using Coben analysis and angle analyses of Beijing Medical University to collect data before and after maxillary protraction. Results  According to Coben analysis measurements, the height of facies cranii increased after maxillary protraction. The depth of lower face decreased, whereas that of mid-face increased and the Ptm-A value increased significantly in the mid-face (P<0.001). In the angle analysis of Beijing Medical University, SNA, ANB, U1/NA, U1/SN, MP/SN, and Y-axis angles increased significantly (P<0.001), whereas SNB, U1/L1 (P<0.001), and L1/MP (P<0.05) decreased. Conclusion  Maxillary protraction has a significant effect on growing skeletal Class Ⅲ malocclusions with the chief mechanism of Ptm-A value just diagnosed as minor by Coben analysis. Coben analysis is visual and clear in identifying pathogenic mechanisms of Class Ⅲ malocclusions.

 Objective  This study aims to compare the treatment outcomes in patients with maxillary dentoalveolar protrusion by applying different anchorage methods via three-dimensional model measurement. Methods  A total of 46 patients with maxillary dentoalveolar protrusion treated with bilateral maxillary first premolar extractions and high anchorage were selected. The subjects were randomly divided into three groups according to the type of anchorage applied, which included implant, extraoral, and Nance arch anchorages. The maxillary dental models were made before treatment and after space closure of maxilla. The movements of the maxillary central incisors and first molars were measured via a three-dimensional model measurement, and the amounts of movement were compared among the three groups. Results  The sagittal lingual movements of the maxillary central incisors were (-6.661±1.328), (-5.939±1.806), and (-5.788±2.009) mm for the implant, extraoral, and Nance arch anchorage groups, respectively, with no significant difference among the three groups (P=0.121). The corresponding vertical movements of the maxillary central incisors were (0.129±1.815) mm intrusion, and (-2.162±2.026), (-2.623±1.776) mm extrusion. Significant difference was found between the implant anchorage group and the other groups (P<0.05). The corresponding sagittal mesial movements of the maxillary first molars were (0.608±1.045), (1.445±1.462), and (1.503±0.945) mm. The corresponding vertical movements of the maxillary first molars were (0.720±0.805) mm intrusion, (0.076±0.986) mm intrusion, and (-0.072±0.690) mm extrusion. Significant difference was found between the implant anchorage group and the other two groups (P< 0.05). In the transverse direction, the first molars all moved lingually with no significant difference among the three groups (P>0.05). Conclusion  Implant anchorage may be superior in the vertical control of the maxillary incisors and in the sagittal, as well as in the vertical control of the maxillary molars, compared with the traditional anchorages during the treatment of patients with maxillary dentoalveolar protrusion.

Objective  This study aims to do the following: construct a three-dimensional finite element model of an labial inverted impacted maxillary central incisor and its supporting tissues, analyze stress distribution in the periodontal tissue when various tractions are exerted, and provide references for treating impacted maxillary central incisor. Methods  A three-dimensional finite element model of labial inverted impacted maxillary central incisor and its periodontal tissues was established using Mimics 10.01 and Ansys 14.0 software based on original cone beam computed tomography (CBCT) data. Various traction values (20, 30, 40, 50, 60, and 70 g) were exerted on the incisal margin in the direction perpendicular to the impacted tooth. Different Von Mises stress values were determined. Results  Stress distribution on the periodontal ligament increased with traction size. When 30 g traction was exerted on the labial inverted impacted maxillary central incisor, the Von Mises stress was 24 919.0 Pa, which was within the range of the optimum force and close to its maximum value. Conclusion  The optimum traction for early orthodontic treatment of labial inverted impacted maxillary central incisor is nearly 30 g.

 Objective This work lays the foundation for establishing a digital model database with normal occlusion. A digital dental cast is acquired through grating projection, and model features are measured through reverse engineering. Methods The grating projection system controlled by a computer was projected onto the surface of a normal dental model. Threedimensional contour data were obtained through multi-angle shooting. A three-dimensional model was constructed, and the model features were analyzed by using reverse engineering. The digital model was compared with the plaster model to determine the accuracy of the measurement system. Results The structure of three-dimensional reconstruction model was clear. The digital models of two measurements exhibited no significant difference (P>0.05). When digital and plaster models were measured, we found that the crown length and arch width were not statistically different (P>0.05), whereas the difference between the crown width and arch length was statistically significant (P<0.05). Conclusion The reconstruction of a digital model by using the grating projection technique and reverse engineering can be used for dental model measurement in clinic al and scientific research and can provide a scientific method for establishing a digital model database with normal occlusion.

 Objective  This study aims to investigate the effects of mineral trioxide aggregate (MTA) and calcium hydroxide on proliferation and differentiation of human pulp cells from primary and permanent teeth. Methods  Cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay. The mRNA expression levels of dentinogenesis-related factors, including alkaline phosphatase (ALP) and dentin sialophosphoprotein (DSPP), and odontoclastogenesis-related factors, such as osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL), were determined by real time polymerase chain reaction (PCR). Results Primary and permanent pulp cells treated with calcium hydroxide exhibited significantly lower proliferation rates than the control cells (P<0.01). By contrast, the MTA-treated group showed significantly higher proliferation rates than the control group (P<0.01). Real time PCR results showed that calcium hydroxide-treated primary pulp cells exhibited significantly decreased ALP, DSPP, and OPG expression compared with the control group (P<0.01). Conversely, the MTA-treated group displayed significantly increased ALP, DSPP, and OPG expression (P<0.01). Calcium hydroxide-treated primary pulp cells also exhibited significantly upregulated RANKL expression (P<0.01); by contrast, MTA-treated cells did not show any change in RANKL expression (P>0.05). Likewise, MTA-treated permanent pulp cells showed significantly upregulated ALP and DSPP expression (P<0.01). However, the calcium hydroxide-treated group remained almost the same as the control group (P>0.05). Neither MTA nor calcium hydroxide affected OPG and RANKL expression in permanent pulp cells (P>0.05). Conclusion  MTA is more suitable as a pulp-capping agent, particularly in primary teeth, than calcium hydroxide.

Objective  This study aimed to detect the difference in the expression levels of autolysin atlS gene of Streptococcus gordonii (S. gordonii) at different growth stages and pH values, as well as to analyze the factors regulating atlS gene expression in S. gordonii. Methods  S. gordonii wild strains (ATCC 35105) were collected at different growth stages (early exponential phase, mid-exponential phase, late exponential stage, and platform stage) and pH values (pH 7 and pH 5.5), and total RNA was extracted by using a conventional method. Fluorescence quantitative polymerase chain reaction (FQ-PCR) was used to measure the relative mRNA expression of atlS gene, with bacterial 16S rRNA as internal reference, for a comparison of the mRNA levels of atlS gene expression in S. gordonii at different growth stages and pH values. Results  FQ-PCR results showed that atlS gene expression increased with gradually increasing growth stage under neutral conditions and was higher than that under acidic conditions (P<0.05). Conclusion  The atlS gene expression in S. gordonii is influenced by growth stage and pH value factors.

Objective  To evaluate the effect of concentrated growth factor extract (CGFe) on the proliferation and differentiation of MC3T3-E1 osteoblasts attached to sandblasted and acid etched titanium surfaces. Methods Trials were divided into experimental and control groups. The experimental group used α-MEM that contained CGFe (10% FBS), whereas the control group only used α-MEM (10% FBS). MTT assay was employed to detect the number of osteoblasts on the first, third, and fifth days. Alkaline phosphatase (ALP) activity and scanning electron microscope (SEM) were used to detect the osteoblast differentiations on the third and fifth days and to observe the osteoblast extensions on titanium surfaces for 12 h, respectively. Meanwhile, the levels of the osteogenetic biomarkers Runt-related transcription factor-2 (Runx2) and Osterix (Osx) on the third and seventh days were quantified via real-time polymerase chain reaction (PCR). Results  MTT assay indicated that on the first, third, and fifth days, the absorbance in the experimental group significantly increased than that in the control group (P<0.05). ALP activity: on the third and fifth days, the absorbance of the experimental group was significantly higher than that of the control group (P<0.05). SEM: at 12 h, the extension of the experimental group cells was larger than that of the control group. Real-time PCR: given the standardization in the group, the gene expression level of the control group on the third day was 1, and the Runx2 and Osx gene expressions in the experimental group were larger than those of the control group. Conclusion  CGFe can efficiently stimulate the proliferation, differentiation and extension of MC3T3-E1 cells.

Objective  This study aims to assess and compare the prevalence of Porphyromonas endodontalis (P. endodontalis) in root canals associated with primary and secondary endodontic infections by using 16s rDNA PCR and real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR). Methods  A total of 120 adult patients with one radiographically documented periapical lesion were included. Sixty teeth presented with primary endodontic infections and 60 with secondary endodontic infections requiring retreatment. P. endodontalis was identified by using 16s rDNA PCR techniques. The positive DNA expression of P. endodontalis in two types of infected root canals were quantitatively compared by using SYBR GREEN Ⅰ RTFQ-PCR. Results  The prevalence of P. endodontalis in the root canals with primary endodontic infections was significantly higher than that in root canals with secondary endodontic infections (P=0.001). However, RTFQPCR results showed no significant difference in DNA expression quantities between the primary and secondary endodontic infections root canals (P=0.303). Conclusion  P. endodontalis is more highly associated with root canals having primary endodontic infections, although P. endodontalis colonize in both root canals with primary and secondary chronic apical periodontitis.

Geographic tongue, also called benign migratory glossitis, is a common and superficial benign inflammatory disorder that affects the tongue epithelium. The majority of geographic tongue lesions typically manifest as irregular central erythematous patches. These lesions, which are caused by the loss of filiform papillae, are defined by an elevated whitish bandlike border that can change location, size, and pattern over a period of time. Histological observations of the oral mucosa affected by geographic tongue revealed nonspecific inflammation. Some reports described cases of migratory stomatitis, wherein lesions simultaneously manifested on the extra lingual oral mucosa. This condition is also called ectopic geographic tongue, which is clinically and histologically similar to the type normally confined to the tongue. In most cases, patients are asymptomatic and do not require treatment. The condition may spontaneously exhibit periods of remission and exacerbation with good prognosis. The specific etiology of geographic tongue remains unknown. Geographic tongue is age-related and is prevalent among young individuals. Various etiological factors that have been suggested in literature include immunological factors, genetic factors, atopic or allergic tendency, emotional stress, tobacco consumption, hormonal disturbances, and zinc deficiency. Geographic tongue may coexist with other disorders, such as fissured tongue, psoriasis, diabetes mellitus, gastrointestinal diseases, burning mouth syndrome, and Down syndrome. Experts currently disagree on whether geographic tongue is an oral manifestation of psoriasis. Moreover, some scholars suggest that geographic tongue is a prestage of fissured tongue. The objective of this review is to summarize current research on risk factors of geographic tongue.

 Autophagy is a highly conservative biological behavior in eukaryotic cells. This dynamic process involves“wrapping” cytoplasmic components and combining with lysosomes in cells for catabolism. The catabolic effect of autophagy can eliminate toxic substances in cells, maintain homeostasis in the intracellular environment, and produce small molecules, such as amino acids, which nourish cells, thereby allowing them to survive. Autophagy can inhibit the occurrence of tumors by maintaining homeostasis in the intracellular environment. However, it can promote the proliferation, invasion, and metastasis of malignant tumor cells. Autophagy can regulate the microenvironment of tumor cells and has an important role in a series of processes, such as anoikis, tumor dormancy, and epithelial–mesenchymal transition.

 Chondrosarcoma is extremely rare in maxillofacial soft tissue. A case diagnosed as well-differentiated chondrosarcoma in the left parotid region was reported. The clinic pathological features, diagnosis, treatment, and prognosis were discussed with the literature review.

Myeloid sarcoma (MS) is a localized extramedullary mass of immature granulocytic cells. MS may be found in any location, but intraoral occurrence is rare. This report presents a case of MS in the gingiva.