Lihong Ge

Peking University, Peping, Beijing, China

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Publications (8)18.47 Total impact

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    ABSTRACT: Purpose: To determine the effect of mechanical tooth cleaning by toothbrush and dental floss on mutans streptococci in the saliva of preschool children. Materials and Methods: This blinded, randomised controlled clinical trial included 54 3-year-old preschool children with detectable mutans streptococci in saliva. The children were randomly divided into a test and a control group. Dental college students cleaned the teeth of test group participants with toothbrush and dental floss under the indication of a plaque disclosing agent once a day. The control group received no intervention. Dentocult SM Strip mutans (D-SM) strips were used to test the mutans streptococci in saliva. Results: The D-SM test scores declined from 1.82 to 0.95 for the test group after the teeth were cleaned 10 times (P < 0.001) and the scores increased to 1.62 after tooth cleaning ceased for 2 weeks (P > 0.05 compared with baseline). The D-SM level of the control group did not change significantly. Conclusion: Meticulous and continuous plaque control with toothbrush and dental floss can decrease the mutans streptococci level in preschool children. However, the effect ceased as the intervention ceased.
    Oral health & preventive dentistry 06/2014; · 0.53 Impact Factor
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    ABSTRACT: The health of human teeth depends on the integrity of the hard tissue and the activity of the pulp and periodontal tissues, which are responsible for nutritional supply. Without the nourishing of the pulp tissue, the possibility of tooth fracture can increase. In immature permanent teeth, root development may be influenced as well. This study explored the potential of using autologous dental pulp stem cells (DPSCs) to achieve pulp regeneration in a canine pulpless model. The establishment of the pulpless animal model involved pulp extirpation and root canal preparation of young permanent incisor teeth in beagles. Autologous DPSCs were obtained from extracted first molars and expanded ex vivo to obtain a larger number of cells. The biological characteristics of canine DPSCs (cDPSCs) were analyzed both in vitro and in vivo by using the same method as used in human DPSCs. cDPSCs were transplanted into the pulpless root canal with Gelfoam as the scaffold, and root development was evaluated by radiographic and histologic analyses. cDPSCs with rapid proliferation, multiple differentiation capacity, and development potential were successfully isolated and identified both in vitro and in vivo. After they were transplanted into the pulpless root canal with Gelfoam as the scaffold, DPSCs were capable of generating pulp-like tissues containing blood vessels and dentin-like tissue. Thickening of the root canal wall was also observed. This study demonstrates the feasibility of using stem cell-mediated tissue engineering to realize pulp regeneration in immature teeth.
    Journal of endodontics 02/2013; 39(2):195-201. · 2.95 Impact Factor
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    ABSTRACT: Dens invaginatus is a rare developmental malformation of a tooth caused by the invagination of the tooth crown before biological mineralization occurs. The complex anatomy of these teeth makes nonsurgical endodontic treatment difficult and more so when there is presence of periapical periodontitis with open apex. The endodontic treatment of dens invaginatus is a challenge, especially in the case of periapical periodontitis with open apex. Pulp revascularization is a conservative endodontic treatment that has been introduced in recent years. Presented here is a variant approach for the treatment of immature dens invaginatus type II with periapical periodontitis, which combines filling of the invagination and pulp revascularization. After accessing the pulp chamber, the main canal and the invagination were explored. The root was thoroughly disinfected by irrigating and medication, invagination was filled, and the main canal was revascularized. Then the coronal sealing was made by glass ionomer cement and composite resin. Radiograph taken regularly and computed tomography scan were used to investigate the healing of the periapical lesion and development of the root. In the subsequent follow-up, the periapical lesion was completely eliminated, the open apex was closed, and the wall of the root was thickened. For type II immature dens invaginatus with large periapical lesion, conservative endodontic treatment should be considered before periapical surgery. With sufficient infection control, pulp revascularization can be an effective alternative method.
    Journal of endodontics 02/2013; 39(2):288-92. · 2.95 Impact Factor
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    ABSTRACT: Cyclin D1 (CCND1) plays a critical role in the G1 to S-phase cell cycle transition. Data on the association between the CCND1 A870G polymorphism and oral cancer are conflicting. To assess the relationship between the CCND1 A870G genotype and the risk of developing oral cancer, we performed a meta-analysis. We searched PubMed to December 1, 2011, for studies on this topic that had been published in the English. For each study, we calculated odds ratios (ORs) and 95 % confidence intervals (CIs), assuming the frequency of allele comparison, homozygote comparison, recessive and dominant genetic models. We then calculated pooled ORs and 95 % CIs. Seven studies were included in the meta-analysis. The CCND1 G allele was not associated with oral cancer in the frequency of allele comparison (G vs. A: OR = 0.882; 95 % CI = 0.684-1.137; p = 0.001 for heterogeneity). In the subgroup analysis, the CCND1 G allele was associated with a borderline significantly decreased risk of developing oral cancer in Asians in the frequency of allele comparison (G vs. A: OR = 0.800; 95 % CI = 0.636-1.006; p = 0.089 for heterogeneity), and the association between the GG genotype and oral cancer was significant in Asians with respect to both the homozygote comparison (GG vs. AA: OR = 0.644; 95 % CI = 0.491-0.843; p = 0.186 for heterogeneity) and the dominant genetic model (GG + AG vs. AA: OR = 0.713; 95 % CI = 0.584-0.870; p = 0.293 for heterogeneity). Our analysis provides evidence that genotypes for the CCND1 A870G polymorphism may be associated with an increased risk of developing oral cancer in the Asian population.
    Molecular Biology Reports 10/2012; · 1.96 Impact Factor
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    ABSTRACT: The most important events during the regulation of tooth development were inductive interactions between the epithelial and mesenchymal tissues. The expression of Pax9 had been shown to specifically mark the mesenchymal regions at the prospective sites of all teeth prior to any morphological manifestations. Here, we investigated the PAX9 gene as a candidate gene for hypodontia in five unrelated Chinese patients with tooth agenesis. Direct sequencing and restriction enzyme analysis revealed a novel heterozygous mutation c.480C>G (p.160Tyr>X, Y160X) in a patient who was missing 20 permanent teeth (the third molars excluded) and 6 primary teeth. The mutation was a nonsense mutation, leading to a premature stop codon in exon 2 of PAX9 gene. PCR analysis of complementary DNA from cultured lymphocytes of the affected individual could not indicate the complete degradation of the mutated transcript. Promoter reporter assays revealed reduced transcriptional activity of the mutated PAX9 protein suggesting that the severe phenotype may result from haploinsufficiency of PAX9. In another patient with 15 missing permanent teeth (the third molars excluded), we found the c.219insG mutation previously reported by Stockton.
    Mutagenesis 11/2011; 27(3):313-7. · 3.50 Impact Factor
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    ABSTRACT: To evaluate the efficacy of laser fluorescence (LF) device in detecting approximal caries in primary molars. Two hundred and sixteen primary molars from 96 children were inspected visually to identify possible caries with contact approximal surfaces. Target molars and their contralateral molars were examined using bitewing radiographs (BR) and LF. Depending on the examination findings, invasive treatments were performed on molars to identify the presence of cavitation. Of 256 surfaces evaluated from 216 primary molars, 128 were intact, 39 had white spots, and 89 had cavities. At the white-spot threshold, sensitivity and specificity, respectively, were 2.56% and 94.87% for visual inspection (VI); 64.10% and 97.43% for BR; and 56.41% and 94.87% for LF. At the cavity threshold, sensitivity and specificity, respectively, were 70.79% and 95.51% for VI; 97.75% and 93.26% for BR; and 92.14% and 97.75% for LF. Significant differences between intact surfaces and white spots, and white spots and cavities were shown through LF readings. Both LF and BR can detect cavitations on approximal surfaces of primary molars. LF could be an alternative to radiographs in detecting approximal caries in primary molars.
    International Journal of Paediatric Dentistry 09/2011; 22(2):132-8. · 1.54 Impact Factor
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    ABSTRACT: BACKGROUND.  The genotypic diversity of both Streptococcus mutans and Streptococcus sobrinus in children with different caries experience remains unclear. AIM.  To investigate the genotypic diversity of S. mutans and S. sobrinus in children with severe early childhood caries (SECC) and in caries-free (CF) children. METHODS.  Stimulated saliva of 87 SECC and 91 CF children aged 3-4 years was collected and submitted to cultivation, and MS colonies were enumerated. The genomic fingerprint analysis of S. mutans and S. sobrinus was carried out using AP-PCR. RESULTS.  One to five genotypes of S. mutans were colonized in an oral cavity of SECC and CF children; 85.5% SECC children and 57.9% CF children harboured more than one genotype of S. mutans. One to three genotypes of S. sobrinus were detected from each SECC child; 31.25% SECC children harboured more than one genotype of S. sobrinus. And one genotype was colonized in each CF child. S. mutans isolates from different individuals displayed distinctive DNA fingerprints. CONCLUSIONS.  DNA fingerprints of S. mutans and S. sobrinus isolates from 3- to 4-year-old children displayed genetic polymorphism, and S. mutans has greater genetic diversity than S. sobrinus. SECC children harboured more genotypes of S. mutans and S. sobrinus than CF children.
    International Journal of Paediatric Dentistry 06/2011; 21(6):422-31. · 1.54 Impact Factor
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    ABSTRACT: Cleidocranial dysplasia (CCD) is a dominantly inherited skeletal dysplasia caused by mutations in the osteoblast-specific transcription factor-encoding gene, RUNX2. To correlate different RUNX2 mutations with CCD clinical spectrum, we studied six independent Chinese CCD patients. In five patients, mutations were detected in the coding region of the RUNX2 gene, including two frameshift mutations and three missense mutations. Of these mutations, four were novel and one had previously been reported. All the detected mutations were exclusively clustered within the Runt domain that affected conserved residues in the Runt domain. In vitro green fluorescent protein fusion studies showed that the three mutations--R225L, 214fs and 172fs--interfered with nuclear accumulation of RUNX2 protein, while T200I mutation had no effect on the subcellular distribution of RUNX2. There was no marked phenotypic difference between patients in craniofacial and clavicles features, while the expressivity of supernumerary teeth in our patient cohort had a striking variation, even among family members. The occurrence of intrafamilial clinical variability raises the view that hypomorphic effects and genetic modifiers may alter the clinical expressivity of these mutations. Our results provide new genetic evidence that mutations involved in RUNX2 contribute to CCD.
    Mutagenesis 11/2010; 25(6):589-94. · 3.50 Impact Factor

Publication Stats

43 Citations
18.47 Total Impact Points

Institutions

  • 2013
    • Peking University
      Peping, Beijing, China
  • 2010–2012
    • Peking University School of Stomatology
      Peping, Beijing, China