[Investigation and analysis of dental and jaw deformities of junior middle school students and their parents' awareness of correction in Ganzhou city].

PURPOSE: To investigate and analyze orthognathic deformities of junior middle school students in Ganzhou City and their parents' awareness of correction. METHODS: From January 2019 to December 2020, a stratified cluster sampling method was adopted to select 2 189 middle school students in Ganzhou City and an anonymous self-filling questionnaire survey was conducted. The difference between the students with and without correction of dental deformities was compared. The difference between parents of students with and without orthodontic teeth deformity was analyzed. The data were statistically analyzed with SPSS 18.0 software package. RESULTS: Among 2 189 junior high school students, the incidence of dental and jaw malformations was 54.04%, and the correction rate of dental and jaw malformations was 33.64%. The correction rate of dental deformities in girls was significantly higher than in boys(P＜0.05). The correction rate of tooth and jaw deformity in urban students was significantly higher than in rural students(P＜0.05). In terms of the students' judgment on the appearance and function of their teeth, some in the orthodontic group mentioned that their teeth were irregular, they would not intentionally cover their teeth with their hands, they cared about others' opinions on their teeth, not satisfied with their feelings about the appearance of their teeth and their teeth affected chewing or articulation were significantly higher than those in the group without orthodontic deformity(P＜0.05). In terms of students' cognition of teeth and jaw deformities, the proportion of students in the orthodontic group who did not know about the orthodontic treatment was significantly lower than that in the group without orthodontic treatment(P＜0.05). In terms of the concerns about orthodontic treatment, the percentages of the orthodontic treatment group worried about the impact of wearing orthodontic devices on eating, brushing, appearance, fear of tooth extraction and pain were significantly lower than those of the group without orthodontic treatment (P＜0.05). Bachelor degree or above educational level of parents and the proportion of working in institutions and public institutions and state-owned enterprises in the orthodontic group were significantly higher than those in the non-orthodontic group(P＜0.05). The family monthly income≥10 000 yuan, the proportion of those who thought their children need orthodontic treatment, the proportion of those who were willing to spend time to help their children with orthodontic treatment, and the proportion of those who supported to pay for orthodontic treatment for their children were significantly higher than those without orthodontic treatment(P＜0.05). The proportion of parents satisfied with their children's dental condition in the orthodontic group was significantly lower than that in the non-orthodontic group (P＜0.05). CONCLUSIONS: Junior middle school students in Ganzhou City have the characteristics of higher prevalence rate of dental and jaw malformations. The correction rate of dental and jaw malformations is significantly different between female and male students, as well as urban and rural students. The lack of cognition of students and their parents, education level of parents and family economic level may affect the demand for orthodontic treatment of dental deformities.

Efficacy of crown lengthening for restoration of maxillary anterior tooth defects.

OBJECTIVE: The appearance of the gingival tissue around the teeth is essential in the aesthetics of the anterior maxillary region of the oral cavity. Abnormalities in symmetry and contour can significantly compromise the appearance of the natural or restored dentition, so the outcome is highly relevant to treatment choice. This study evaluated the efficacy of crown lengthening for restoration of maxillary anterior tooth defects. METHODS: A total of 80 patients (87 affected teeth) diagnosed with maxillary anterior tooth loss in Ganzhou People's Hospital between May 2020 and August 2021 were retrospectively enrolled and divided into an experimental group or a reference group according to different treatment methods, with 40 cases in each group. The reference group received a post and core procedure, while the experimental group received crown lengthening plus a post and core procedure. Outcome measures included clinical efficacy, gingival periodontal-related indices, and dental aesthetics indices. RESULTS: Crown lengthening plus post and core procedure was associated with a significantly higher clinical efficacy (95.65%) versus post and core procedure alone (78.05%) (P<0.05). Postoperatively, the levels of probing depth (PD), plaque index (PLI), bleeding index (BI), and gingival index (GI) were lower in patients of the experimental group than those in the reference group (all P<0.05). Crown lengthening plus post and core procedure resulted in more Kay class I and II patients and fewer Kay class III and IV versus the post and core procedure alone (P<0.05). The position of gingival margin (PGM) and gingival recession (GR) of patients in the experimental group were higher than those in the reference group after operation (P<0.05). Logistic regression analysis showed that the morphology of broken ends, plaque control, hygiene habits, and smoking were influencing factors for maxillary anterior tooth defects (all P<0.05). Patients were more satisfied (97.50%) in the experimental group than those in the reference group (80.00%) (P<0.05). CONCLUSION: Crown lengthening improves the periodontal condition of patients with maxillary anterior tooth loss, reduces gingival sulcus bleeding, and improves dental aesthetics and patient satisfaction. Further clinical studies are required prior to clinical promotion.

[Effect of ultrasonic curettage combined with sodium hyaluronate gel on chronic periodontitis and its effect on inflammatory factors hs-CRP, MCP-1 and MMP-13 in gingival crevicular fluid].

PURPOSE: To investigate the effect of ultrasonic curettage combined with sodium hyaluronate gel in the treatment of chronic periodontitis (CP) and the effect on inflammatory factor hypersensitive C-reactive protein (hs-CRP), monocyte chemotactic protein 1 (MCP-1) and matrix metalloproteinase 13 (MMP-13) in gingival crevicular fluid. METHODS: A total of 102 patients with CP from October 2021 to October 2022 were selected, divided into experimental group (n=51) and control group (n=51) by random number table method. The control group received ultrasonic subgingival curetage, and the experimental group received sodium hyaluronate gel adjuvant therapy on the basis of the control group. The periodontal rehabilitation indexes, clinical efficacy and the changes of gingival crevicular fluid hs-CRP, MCP-1 and MMP-13 were compared between the two groups. The periodontal pathogens, bone metabolism indexes and the occurrence of adverse events during treatment were compared between the two groups. The data were statistically analyzed using SPSS 22.0 software package. RESULTS: After treatment, the sulcus bleeding index (SBI), gingival index (GI), plaque index (PLI), periodontal pocket depth (PD) and attachment level (AL) of the two groups were significantly lower than before treatment (P＜0.05), and even significantly lower(P＜0.05) in the experimental group. Total effective rate of the experimental group was significantly higher than that of the control group(P＜0.05). hs-CRP, MCP-1 and MMP-13 in both groups after treatment were significantly lower than before treatment(P＜0.05), and hs-CRP, MCP-1 and MMP-13 in the experimental group after treatment were significantly lower than those in the control group(P＜0.05). The detection rates of Porphyromonas gingivalis, Forsetanella and Treponema dentalis were significantly lower in both groups after treatment than before treatment (P＜0.05), and the detection rates of the above indexes in the experimental group after treatment were significantly lower than those in the control group(P＜0.05). After treatment, the C-terminal peptide(CTX) of type Ⅰ collagen was significantly lower than that before treatment, and bone gla protein(BGP) was significantly higher than that before treatment(P＜0.05). The CTX and BGP of the experimental group were significantly lower than that of the control group and significantly higher than that of the control group(P＜0.05). There was no significant difference in the incidence of total adverse reactions between the two groups(P＞0.05). CONCLUSIONS：Ultrasonic curettage combined with sodium hyaluronate gel in the treatment of CP can promote periodontal tissue rehabilitation, enhance short-term efficacy, inhibit synthesis of inflammatory factors in gingival crevicular fluid, kill periodontal pathogens, regulate bone metabolism, and is safe and reliable.

Traumatic posterior atlantoaxial dislocation without associated fracture and neurological deficit.

Traumatic posterior atlantoaxial dislocation without related fractures of the odontoid process and anterior arch of the atlas is exceedingly rare, with only ten published cases reported so far in English literature. We report on a 44-year-old man with post-traumatic posterior displacement of the atlas with respect to the axis without any associated fractures and neurological deficit caused by a crush injury in earthquake. Radiographs, computed tomography and magnetic resonance imaging revealed posterior displacement of the atlas with the odontoid peg lying anterior and to the right of the anterior arch of the atlas. Partial odontoidectomy and posterior fixation with bone graft were performed in one-stage procedure after several unsuccessful attempts of closed reduction. The patient did not have neurological deterioration after operation.

Preparation, Characterization and Drug Release of Salicylic Acid Loaded Porous Electrospun Nanofibers.

BACKGROUND: Salicylic acid (SA), used as an important component in a lot of skin care products, has been reported widely. And because of large specific surface area, high porosity and good surfactivity, electrospun drug-loaded nanofibers have been widely used in various applications including wound dressing, tissue engineering and drug release. Particularly, the electrospun SA loaded porous nanofibers could be fabricated by regulating electrospinning (ES) parameters, and the release property of SA from nanofibers could be improved by the porous structure. Few relevant patents to the topic have been reviewed and cited. METHODS: Electrospun polylactic acid (PLA) porous nanofibers with different contents of SA were prepared successfully by modulating the ES parameters. The morphology and structure of the electrospun SA/PLA porous nanofibers were characterized by scanning electron microscopy (SEM) and flourier transformation infrared spectroscopy (FTIR). And the cumulative drug release rates of SA from SA/PLA porous nanofibers were measured using ultraviolet spectrophotometer (UV). RESULTS: The PLA concentration of 8 wt%, the SA concentrations of 4, 8, 12 wt% and the applied voltage of 15kv were selected as the optimal ES parameters. And the release percentage of low SA content was higher than that of high SA content, and the porous nanofibers had a higher cumulative release percentage of SA than the nonporous nanofibers. CONCLUSION: The release property of SA from nanofibers could be improved by the porous structure. It will provide a continuous and effective method for treating wounds.

Culture of osteoblasts on bio-derived bones.

OBJECTIVE: To study the effect of bio-derived bones, as substitutes of autogenous bone grafts and demineralized cadaver bones, on the attachment, spreading and proliferation of isolated osteoblasts. METHODS: Osteoblasts were isolated from the calvaria of a fetal rabbit through sequential collagenase digestion. In the attachment study, the osteoblasts labeled with 3H-leucine were incubated with the bio-derived bone materials in sterile microcentrifugable tubes for 15, 90 and 180 minutes, and 24 hours, respectively. The attached cells were collected and the radioactivity was measured with liquid scintillation spectrometry. In the proliferation study, the osteoblasts were cultured with the bio-derived bone materials for 24 hours and 3H-thymidine was added during the last 2 hours of the incubation. The attached cells were collected and the radioactivity was measured with liquid scintillation spectrometry. Osteoblasts were seeded on the bone graft materials for 60 or 120 minutes, 24 or 48 hours, and 3 or 7 days, then the co-culture was processed for scanning electron microscopy to observe the interaction of osteoblasts and the bio-derived bone materials. RESULTS: Osteoblasts attached to the bio-derived bone materials in a time-dependent manner. There were significantly (P<0.05) more attached cells after 180 minutes than after 15 and 90 minutes of incubations (P<0.05). Osteoblasts were proliferated in a large amount on the surface and in the materials. Osteoblasts seeded onto 100 mg bio-derived bones resulted in significantly (P<0.05) more measurable proliferation than those seeded onto 10 mg bones. Osteoblasts appeared round as they attached to the materials, then flattened and spread over with time passing. CONCLUSIONS: Bio-derived bones can provide a good environment for the attachment and proliferation of osteoblasts.

[Bio-derived bone material].

OBJECTIVE: To review researches on bone defect repaired by different kinds of bio-derived bone. METHODS: The recent relevant literatures were extensively investigated. Preparation of bio-derived bone and effect of bone defect repair were reviewed. RESULTS: The allogeneic and xenogeneic bone treated by different physicochemical method were not only the substitution for bone but also the scaffold material co-cultured with seed cells to reconstruct tissue engineered bone. CONCLUSION: The tissue engineered bio-derived bone is a breakthrough for treatment of bone defect.

[Experimental study on repairing segmental bone defect with bio-derived bone preserved by various methods].

OBJECTIVE: To study the difference of repairing segmental bone defect with bio-derived bone preserved by various methods. METHODS: Freeze-dried biomaterials had been stored in two different preservation solutions for three months, while the biomaterials stored for same period were observed as control group. The experimental model of 15 mm radial segmental defect was made in 60 New Zealand white rabbits, which were divided into groups A, B and C according to transplant materials preserved by various methods. Groups A and B were deeply divided into A1 and A2 subgroups, B1 and B2 subgroups according to whether materials were cocultured with osteoblasts. Tissue engineered bone was used to repair bone defects of left limbs in A1 and B1 subgroups, while simple material to repair defects of right limbs in A2 and B2 subgroups. Group C was divided into C1 and C2 subgroups. Freeze-dried material was used to repair bone defects of the left limbs, while defects of the right limbs as blank control group. The samples were harvested and observed by the roentgenographical, histomorphological, biomechanical and computerized graphical analysis at 4, 8 and 16 weeks. RESULTS: All of the defects treated with implants exhibited new bone formation 4, 8 and 16 weeks postoperatively, increasing with time. The radiological, histomorphological and biomechanical evaluation showed that the ability of new bone formation was arranged in 6 subgroups as follows: A1>A2>C1>B1>B2>C2, the difference was significant between them (P<0.001, P<0.05). The ability of new bone formation was strongest and at 16 weeks the defect was bridged with the appearance of marrow cavities in A1 subgroup, the biomechanical properties in implants approached to those of normal bone. CONCLUSION: The choice of proper preservation solution can improve the ability of repairing bone defect.

[Effect of various storage methods on cellular compatibility of bio-derived bone].

OBJECTIVE: To study the effect of various storage methods on cellular compatibility of bio-derived bone. METHODS: Freeze-dried biomaterials had been stored in two different preservation solutions for three months, while the biomaterials stored for the same time were observed as control group. The experiment was divided into groups A, B, C and D according to different storage methods (group A: with materials stored in preservation solution 1; group B: with materials stored in preservation solution 2; group C: with freeze-dried materials; and group D: simple osteoblasts). Osteoblasts at 2 x 10(6)/ml had been cocultured with materials for 1, 3, 5, and 7 days. The cell-material complex was observed under phase microscope and electronic scanning microscope to evaluate the adhesion and growth of osteoblasts; the cell viability and alkaline phosphatase(ALP) activity were measured, and the cell cycle was analysed by flow cytometer. RESULTS: Osteoblasts adhered to materials preserved by different methods, differentiated and proliferated in the hole of materials. The difference of cell viability was not significant between three groups on day 1 and day 3. The cell viability of osteoblasts adhered to three materials was A > C > B group on day 5 and day 7 (P < 0.01, P < 0.05). The ALP activity of osteoblasts adhered to three materials was A > C > B group on day 7 (P < 0.01). The cell cycle of different groups did not change significantly, the abnormal cells were not seen. CONCLUSION: The choice of proper preservation solution can optimize the cellular compatibility of bio-derived bone.