OBJECTIVE: To summarize the open-eruption technique of impacted anterior maxillary teeth, this study reports a technically improved operation on surgical exposure based on dental follicles and evaluates post-treatment periodontal health considering the effect of dental follicles.
METHODS: Patients who underwent open-eruption technique with unilateral labially impacted maxillary central incisors were selected. The impacted teeth were assigned to the experimental group, and the contralateral unimpacted maxillary central incisors were assigned to the control group. In the surgical exposure, the new technique makes use of dental follicles to manage the soft tissue, so as to preserve soft tissue for better aesthetic results and healthier periodontal tissue. Tooth length, root length, alveolar bone loss, and alveolar bone thickness were recorded after the therapy.
RESULTS: A total of 17 patients with unilateral maxillary central incisor impaction were successfully treated. The tooth length and root length of the two groups showed a statistically significant difference between the impacted and homonym teeth, with a shorter length in the impacted tooth (P<0.05). More labial alveolar bone loss was found in the experimental group compared with that in the control group (P<0.05). The outcomes of the cementoenamel junction width, pa- latal alveolar bone loss, and alveolar bone thickness did not indicate statistical significance between the experimental and control groups (P>0.05).
CONCLUSIONS: In the surgical exposure, the new technique uses dental follicles to manage the soft tissue and preserve it for better aesthetic results and healthier periodontal tissues.
目的: 总结既往上前牙区埋伏牙开放式牵引方法的基础上，报告一种基于牙囊的软组织处理技术，并监测治疗后埋伏牙牙根长度变化和牙槽骨丢失量，探讨牙囊在埋伏上颌中切牙唇侧微创开放式牵引中的重要作用。方法: 选择单侧唇侧埋伏上颌中切牙并采用开放式牵引技术治疗的患者，将埋伏中切牙纳入试验组，将对侧未受影响的中切牙纳入对照组。在外科手术暴露埋伏上颌中切牙时，利用埋伏牙周围的牙囊组织进行术区软组织管理，最大程度地保存埋伏牙周围软硬组织量。在埋伏上颌中切牙牵引至牙合平面后，记录其牙长、根长、骨丢失量、骨厚度等测量值。结果: 成功牵引了17例单侧唇侧埋伏上颌中切牙。牵引后试验组与对照组之间，牙长、根长、唇侧骨丢失量的差异有统计学意义（P<0.05），唇-腭釉牙骨质界处宽度、腭侧骨丢失量、唇侧骨厚度、腭侧骨厚度、根尖牙槽骨厚度的差异无统计学意义（P>0.05）。结论: 在外科手术暴露唇侧埋伏上颌中切牙时，本方法利用埋伏牙周围的牙囊组织进行术区软组织管理，最大程度地保存埋伏牙周围软硬组织量，尽可能在牵引萌出后获得更好的美学效果和健康的牙周组织。.

OBJECTIVE: Dental follicle (DF) is made up of mesenchymal cells and fibers surrounding the enamel organ of a developing tooth. It has been shown that cystic and neoplastic lesions can develop from the pericoronal follicles of impacted third molars (ITMs). But the molecular transformation of DF tissues has not yet been uncovered and remains elusive. Accordingly, in the present study, we aimed to investigate the differential expression of lncRNA genes in DF tissues associated with asymptomatic impacted mandibular third molars (IMTMs) that do not show pathological pericoronal radiolucency in radiographic examination.
METHODS: A total of 30 patients with unilateral mesioangular IMTMs were enrolled for the study. The expressions of lncRNA genes were determined in the DF and healthy gingival tissues obtained from study patients. For the determination of lncRNA expression levels, RNA was isolated from the obtained tissues, converted to cDNA samples, and analyzed by quantitative real-time PCR method.
RESULTS: As a result, we found that the gene expression of MEG3 was increased about 10-fold in DF tissues compared to healthy gingival tissues (p < 0.0001). In addition, NORAD expression was found to be upregulated 4.2-fold (p = 0.0002) in DF tissues. Also, expression level of MALAT1 was found to be decreased 1.24-fold (p = 0.584) and TP73-AS1 increased 2.6-fold (p = 0.093) in DF tissues compared to healthy gingival tissues.
CONCLUSIONS: Consequently, present findings suggest that differentially expressed lncRNAs in DFs might be associated with the various levels of cellular events including osteogenic differentiation, DNA damage, and the transformation into odontogenic pathology.
CONCLUSIONS: Expression levels of MEG3 and NORAD lncRNA molecules may guide clinicians in the evaluation of asymptomatic ITM dental follicles that cannot be determined radiologically and during extraction of these teeth for prophylactic purposes.

OBJECTIVE: Despite the high frequency of impacted teeth and increased frequency of lesions in dental follicles (DF) with aging, DF age-changes remain unclear. We compared the global methylation and hydroxymethylation profiles in DF in relation to age.
METHODS: DF associated with impacted lower third molars were obtained from 59 individuals. Global DNA methylation (5mC content) and hydroxymethylation (5hmC) were evaluated by ELISA. We tested the correlation between 5mC and 5hmC content, and the correlation of each with patients\' age. The differences in age, 5mC, and 5hmC in DF from men/women, and location (left/right mandible) was tested.
RESULTS: The mean age of the 59 individuals was 19.56 ± 3.92, ranging from 13 to 31 years, and most were women (n = 39). 5hmC content and age up to 19 years were inversely correlated (Spearman\'s correlation coefficient=-0.552, p = 0.0003, n = 38). There was no relationship between 5hmC and 5mC content. There was no difference in the medians of age (p = 0.25), 5hmC (p = 0.33) and 5mC (p = 0.86) between men/women, nor in the medians of age (p = 0.39), 5hmC (p = 0.99) and 5mC (p = 0.22) between the left/right side of the tooth extraction.
CONCLUSIONS: An inverse correlation between 5hmC and age was established, with no correlation between 5mC and 5hmC content in DF. The biological meaning of such a decrease of global DNA hydroxymethylation with age in DF remains to be clarified.

Dental follicle tissue is a promising resource of mesenchymal stem cells for cytotherapeutic approaches and tissue engineering applications. There are two procedures for banking of human dental follicle stem cells have been reported. Conventional method requires cell isolation, expansion and immediate cryopreservation. Whereas dental follicle stem cells can be isolated from cryopreserved dental follicle fragments. The aim of this study was to compare the characteristics of dental follicle cells isolated from cryopreserved fragments (DFCs-CF) with dental follicle cells recovered from cryopreserved cells (DFCs-CC). Dental follicle fragments obtained after mechanical disaggregation were divided into two parts, with one part maintained in culture, while another part underwent cryopreservation. Dental follicle fragments and dental follicle cells from fresh tissue were stored in liquid nitrogen for 3 months. After thawing, the isolation, morphology, proliferation, cell cycle, colony-forming-unit ability, stemness-related marker expression, apoptosis, and multi-lineage differentiation potential of DFCs-CF were tested compared with DFCs-CC. DFCs-CF expressed mesenchymal stem cells marker, proliferated well, showed similar levels of mRNA for stemness- and apoptosis-related genes and exhibited the capacity of multi-lineage differentiation similar to those of DFCs-CC. These results imply that cryopreservation of dental follicle fragments is an effective banking method for isolation of dental follicle cells.