[Comparison of initial periodontal therapy and its correlation with white blood cell level in periodontitis patients with or without diabetes mellitus].

OBJECTIVE: To compare the clinical efficacy of initial periodontal therapy in periodontitis patients with or without type 2 diabetes mellitus and its correlation with white blood cell counts. METHODS: In this study, 32 chronic periodontitis patients without systemic disease (CP group) and 27 chronic periodontitis patients with type 2 diabetes mellitus (CP+DM group) were enrolled. At admission, all the patients went through periodontal examination and fasting blood examination(baseline). Probing depth (PD), attachment loss (AL), bleeding index (BI), plaque index (PLI), white blood cells (WBC) counts and fasting blood glucose (FBG) were recorded respectively, while hemoglobin A1c (HbA1c) was recorded only in CP+DM group. After that, initial periodontal therapy was performed. All the tests were repeated 3 and 6 months after treatment. The changes of periodontal clinical indexes and WBC levels were compared between the two groups before and after treatment, and the correlation between WBC and periodontal clinical indexes and glucose metabolism indexes were analyzed by generalized linear mixed model. RESULTS: At baseline, the periodontal inflammation and destruction were similar in CP and CP+DM group, but the WBC level was significantly higher in CP+DM groups [(6.01±1.26)×109/L vs. (7.14±1.99)×109/L, P=0.01]. After 3 and 6 months of initial periodontal therapy, the mean PD, AL, BI, and PLI in CP+DM and CP groups were significantly lower than the baseline, and the PD in CP+DM group was further decreased by 6 months compared with 3 months [(3.33±0.62) mm vs. (3.61±0.60) mm, P < 0.05]. However, none of these periodontal indexes showed significant difference between the two groups by 3 or 6 months. In CP+DM group, HbA1c at 3 months and 6 months were significantly lower than the baseline [(7.09±0.79)% vs. (7.64±1.16)%, P < 0.05; (7.06±0.78)% vs. (7.64±1.16)%, P < 0.05], and FBG was significantly lower than the baseline by 6 months [(7.35±1.14) mmol/L vs. (8.40±1.43) mmol/L, P < 0.05]. The WBC level in CP group was significantly lower than the baseline level by 3 months [(5.35±1.37)×109/L vs. (6.01±1.26)×109/L, P < 0.05], while that in CP+DM group was significantly lower than the baseline level by 6 months [(6.00±1.37)×109/L vs. (7.14±1.99)×109/L, P < 0.05]. The analysis of genera-lized linear mixed model showed that WBC level was significantly positively correlated with PD and FBG (P < 0.05). CONCLUSION: Initial periodontal therapy can effectively improve the periodontal clinical status of patients with or without type 2 diabetes mellitus, and have benefits on glycemic control in diabetic patients. However, the response of periodontal indexes and WBC level to initial therapy were relatively delayed in diabetic patients. WBC plays an important role in the correlation between diabetes mellitus and periodontitis.

[Healing of the dento-gingival junction following modified crown lengthening procedure in beagle dogs].

OBJECTIVE: To evaluate the type of wound healing following modified crown lengthening surgery in dog model to provide a biological basis for its clinical application. METHODS: Flap surgery, traditional crown lengthening procedure and modified crown lengthening procedure were performed on the right maxillary central incisor, the left maxillary central incisor and the left maxillary first lateral incisor respectively of five male beagle dogs. The right maxillary first lateral incisors with no surgical intervention were used as controls. Thirty-six weeks after the experimental procedure, tissue blocks were harvested and prepared for histological examination and analysis. RESULTS: Histometric examination of buccolingual sections stained with hematoxylin-eosin demonstrated that the type of wound healing in the flap surgery group was re-attachment, similar to the control group. For the traditional crown lengthening surgery group, all of the five beagle dogs had lamellar cementum defects on root surface, the wound healing of four beagle dogs was new attachment accompanied by new cementum formation at cementum defect areas and the suprac-restal connective tissue was functionally oriented perpendicular to the new cementum. The wound healing of the other beagle dog was long junctional epithelial attachment, in which the junctional epithelium extended to the apical terminus of the cementum defect. In the modified crown lengthening surgery group, four beagle dogs had cementum defects on root surface (two lamellar cementum defects and two shallow platform-like cementum defects), the wound healing of three beagle dogs was new attachment, however, the supracrestal connective tissue was parallel to the root surface. The type of wound healing of another one beagle dog was long junctional epithelial attachment. Wound healing of one beagle dog in this group could not be characterized due to incomplete dissection. CONCLUSION: Wound healing in the modified crown lengthening surgery group was similar to the traditional crown lengthening surgery group, and two types of wound healing were observed: new attachment and long junctional epithelium attachment. Neither type of root treatment procedure (root planing or root reshaping) nor root surface defect pattern (the lamellar cementum defect or shallow platform-like cementum defect) influenced the observed type of wound healing.

[Gene polymorphisms of cytochrome B-245 alpha chain (CYBA) and cholesteryl ester transfer protein (CETP) and susceptibility to generalized aggressive periodontitis].

OBJECTIVE: To explore the correlation of cytochrome B-245 alpha chain (CYBA) rs4673 and cholesteryl ester transfer protein (CETP) rs12720922 polymorphisms with the susceptibility of gene-ralized aggressive periodontitis (GAgP). METHODS: The study was a case-control trial. A total of 372 GAgP patients and 133 periodontally healthy controls were recruited. The CYBA rs4673 and CETP rs12720922 polymorphisms were detected by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). Logistic regression models were used to analyze the correlation of CYBA rs4673 and CETP rs12720922 variants with the susceptibility of GAgP. The interaction between the two gene polymorphisms to the susceptibility of GAgP was analyzed by the likelihood ratio test. The interaction model adopted was the multiplication model. RESULTS: The mean age of GAgP group and control group was (27.5±5.2) years and (28.8±7.1) years respectively. There was significant difference in age between the two groups (P < 0.05). The gender distribution (male/female) was 152/220 and 53/80 respectively, and there was no significant difference between GAgP group and controls (P>0.05). For CYBA rs4673, the frequency of CT/TT genotype in the GAgP group was significantly higher than that in the controls [18.0% (66/366) vs. 10.6% (14/132), P < 0.05]. After adjusting age and gender, the individuals with CT/TT genotype had a higher risk of GAgP (OR=1.86, 95%CI: 1.01-3.45, P < 0.05), compared with CC genotype. There was no statistically significant difference in distributions of the CETP rs12720922 genotypes (GG, AA/AG) between GAgP patients and healthy controls (P>0.05). A significant interaction between CYBA rs4673 and CETP rs12720922 in the susceptibility to GAgP was observed. The GAgP risk of the individuals with CYBA rs4673 CT/TT and CETP rs12720922 GG genotypes was significantly increased (OR=3.25, 95%CI: 1.36-7.75, P < 0.01), compared with those carrying CC and AA/AG genotypes. CONCLUSION: CYBA rs4673 CT/TT genotype is associated with GAgP susceptibility. There is a significant interaction between CYBA rs4673 CT/TT genotype and CETP rs12720922 GG genotype in the susceptibility of GAgP.

[Expression and distribution of calprotectin in healthy and inflamed periodontal tissues].

OBJECTIVE: Calprotectin, the heterdimer of S100A8 and S100A9, is the major cytoplasmic protein of neutrophils, which is also expressed or induced in gingival epithelial cells, activated mononuclear macrophages and vascular endothelial cells. Calprotectin is intimately associated with the initiation and progression of periodontitis, but the in vivo expression patterns of calprotectin in healthy and inflamed periodontal tissue are not fully understood. To observe the expression, distribution and cellular localization of calprotectin in the samples of healthy periodontal tissues and experimental periodontitis tissues of Beagles and to explore their relationship with periodontal inflammation and possible effect. METHODS: Experimental periodontitis model was established by ligation around the mandibular second molar of the Beagle dogs, while the contralateral teeth were healthy controls. Induction duration was 12 weeks, before the dogs were executed. Tissue specimens were demineralized and serial sections were made conventionally. The in vivo expression of calprotectin in the healthy and inflamed periodontal tissues were examined by immunohistochemistry. The in vitro expression of calprotectin in human primary gingival fibroblasts (GFs) and periodontal ligament (PDL) cells were detected by immunocytochemistry. RESULTS: Immunohistochemistry analysis indicated that calprotectin was expressed in gingival epithelial cells and infiltrated neutrophils in the healthy periodontium within the gingival epithelium, S100A8/A9 was most strongly expressed in the junctional epithelium, followed by surface epithelium, and least expressed in the sulcular epithelium. The S100A8/A9 expression levels were sharply defined at the junction between the junctional epithelium and the sulcular epithelium. In periodontal inflammatory lesions, the expression level of calprotectin in sulcular epithelium and junctional epithelium was up-regulated than that in the healthy gingival epithelium. Calprotectin was inducibly expressed in fibroblast-like cells in gingival connective tissue and periodontal ligament tissue, microvascular endothelial cells (ECs) and bone marrow fibroblasts under inflammatory conditions. Additionally, the expression of calprotectin in primary human GFs and PDL cells was confirmed by immunnocytochemistry staining. CONCLUSION: Constitutively expressed in neutrophils and gingival epithelial cells, and calprotectin might maintain the homeostasis and integrity of periodontium. Inflammation-induced expression of calprotectin in GFs, PDL cells, microvascular ECs and bone marrow fibroblasts might process anti-microbial function and promote leukocytes transmigration to defend the host against the microorganisms.

[Short-term outcome of regenerative surgery treating peri-implantitis].

OBJECTIVE: To evaluate the short-term outcome of regenerative surgery for peri-implantitis therapy. METHODS: From March 2018 to January 2019, 9 patients with 10 implants who suffered from peri-implantitis were included in the present research. Vertical bone defect at least 3mm in depth with 2 or more residual bone walls was confirmed around each implant by radiographic examination. Restorations were replaced by healing abutments on 3 implants with the consent of the patients. Guided bone regeneration surgery was performed after a hygienic phase. During surgery, full thickness flaps were elevated on both buccal and lingual aspects. Titanium curette was used for inflammatory granulation tissue removal and implant surface cleaning. The implant surface was decontaminated by chemical rinsing with 3% hydrogen peroxide solution. After being thoroughly rinsed with saline, the bone substitutes were placed in bone defects which were covered by collagen membranes. 6 months after non-submerged healing, the clinical parameters including peri-implant probing depth (PD, distance between pocket bottom and peri-implant soft tissue margin) and radiographic bone level (BL, distance form implant shoulder to the first bone-to-implant contact) were used to evaluate the regenerative outcome. PD was measured at six sites (mesial, middle and distal sites at both buccal and lingual aspects) around each implant, and BL was measured at the mesial and distal surfaces of each implant on a periapical radiograph. RESULTS: The deepest PD and largest BL of each implant ranged from 6-10 mm and 3.2-8.3 mm respectively. All the implants healed uneventfully after surgery. The mean peri-implant PD at baseline and 6 months after surgery were (6.2±1.4) mm and (3.1±0.6) mm respectively, and a mean (3.0±1.5) mm radiographic bone gain was observed, P<0.01. Treatment success was defined as: no sites with residual PD≥6 mm, no bleeding on probing, and BL elevation of at least 1 mm. Nine implants from 8 patients fulfilled the success criteria. Residual pockets with 6 mm in depth and bleeding on probing could be detected in only one implant. CONCLUSION: Within the limitation of the present research, guided bone regeneration surgery can be used for the treatment of bone defect that resulted from peri-implantitis. Significant PD reduction and radiographic bone gain can be obtained after 6 months observation.

[Effect of vertical soft tissue thickness on clinical manifestation of peri-implant tissue in patients with periodontitis].

OBJECTIVE: To observe and investigate the effect of vertical soft tissue thickness on the peri-implant tissue condition and the prevalence of peri-implant disease in patients with history of periodontitis. METHODS: Among 210 patients who showed initial interest of implant therapy, 92 patients were included in this study and received implant surgery during 2010 and 2015. Sixty-six patients with 66 implants finally came back for T2 evaluation. Prior to the implant therapy, all the patients had received periodontal treatment. During the implant placement surgery, the distance from palatal soft tissue edge to the alveolar crest, which was defined as vertical soft tissue thickness (VT), was measured after the buccal full thickness flap was elevated. According to the cut off point which was adopted from the operating characteristic curve, 66 implants within 66 patients were divided into two groups, which were called normal group (VT≤4.5 mm) and thick group (VT>4.5 mm), respectively. Information of the patient's general status, periodontal situation and implant information were recorded. After a follow-up period of 42.9 months, the parameters of peri-implant tissue and condition of peri-implant disease were recorded. Mann-Whitney U test as well as Chi-square test were used to compare the parameters between two groups. Moreover, Kaplan-Meier method was chosen to draw the event(peri-implantitis)-free survival curve. RESULTS: The survival rate of the implants was 100%. At the end of the follow-up examination(T2), the parameters including max PDi, mean PDi, max BIi, mean BIi, mean MBL, MBL at distal side, MBL at mesial side, mean PLIi presented significantly higher values in thick group than in normal group (P < 0.05). Moreover, the prevalence of peri-implantitis and peri-implant disease (peri-implant mucositis & peri-implantitis) in thick group was respectively 34.8% and 73.9%, which was significantly higher than 2.3% and 48.8% respectively in normal group (P<0.05). The prevalence of peri-implant mucositis did not show significant difference in the two groups. In addition, Kaplan-Meier analysis showed that there was significant difference between the event-free survivals of the two groups. CONCLUSION: The vertical soft tissue thickness around implants in patients with periodontitis has a significant effect on the health of the peri-implant tissue. Excessive vertical soft tissue thickness may result in deeper peri-implant probing depth as well as more peri-implant marginal bone loss, and eventually increase the risk of peri-implant disease. The vertical remodeling of soft tissue may be a new direction to indicate the role of periodontitis in peri-implant tissue condition. Moreover, the biological mechanism of the association between soft tissue thickness and peri-implantitis risk as well as effective approaches to prevent the adverse effect of excessive soft tissue thickness on peri-implant tissue is necessary to be investigated.

[Effect of initial periodontal therapy on blood parameters related to erythrocyte and platelet in patients with type 2 diabetes mellitus and chronic periodontitis].

OBJECTIVE: To compare the blood parameters related to erythrocyte and platelet between baseline and 3 months after initial periodontal therapy in patients with both type 2 diabetes mellitus and chronic periodontitis (DM-P). METHODS: According to the International Symposium on Classification of Periodontal Diseases and Conditions in 1999 and the diagnostic criteria of type 2 diabetes mellitus proposed by the World Health Organization in 1999, 35 patients with DM-P were recruited. All the participants received initial periodontal therapy, including oral hygiene instruction, scaling, and root planning provided by one senior periodontist. Original diet, exercise, and medication for blood glucose control were unchanged for all the participants. At baseline and 3 months after initial periodontal therapy, the clinical periodontal parameters, including probing depth (PD), bleeding index (BI) and clinical attachment loss (CAL); erythrocyte-related indexes, including red blood cell (RBC) count, hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), RBC volume distribution width (RDW); platelet-related indexes, including platelet (PLT) count, mean platelet volume (MPV), platelet distribution width (PDW), plateletocrit (PCT) were measured and compared. RESULTS: Compared with baseline, the periodontal parameters, including PD [(3.370±0.601) mm vs. (2.729±0.431) mm], BI [2.160 (1.550~3.410) vs. 1.420 (1.000~2.970)] and CAL [(3.307±1.577) mm vs. (2.990±1.587) mm], were significantly reduced (P < 0.001) three months after the initial periodontal therapy; the erythrocyte-related indexes, including RBC count [(4.727±0.392)×1012/L vs. (4.825±0.394)×1012/L, P=0.010], HGB [(145.886±11.792) g/L vs. (149.200±12.979) g/L, P=0.007] and HCT [43.40% (37.50%~48.50%) vs. 43.80% (38.50%~53.20%), P=0.003], were significantly increased three months after the initial periodontal therapy; PLT count [(216.714±61.900)×109/L vs. (205.886±62.051)×109/L, P=0.016] was significantly reduced 3 months after the initial periodontal therapy. CONCLUSIONS: The initial periodontal therapy can significantly improve blood parameters related to RBC and PLT, which might decrease the risk of vascular complications in DM-P patients.

[Association between root abnormalities and related pathogenic genes in patients with generalized aggressive periodontitis].

OBJECTIVE: To explore the association between the abnormal root morphology and bone metabolism or root development related gene polymorphism in patients with generalized aggressive periodontitis. METHODS: In the study, 179 patients with generalized aggressive periodontitis were enrolled, with an average age of (27.23±5.19) years, male / female = 67/112. The average number of teeth remaining in the mouth was (26.80±1.84). Thirteen single nucleotide polymorphisms (SNPs) of nine genes which related to bone metabolism and root development were detected by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). Root abnormalities were identified using periapical radiographs. The abnormal root morphology included cone-rooted teeth, slender-root teeth, short-rooted teeth, curved-rooted teeth, syncretic-rooted molars, and molar root abnormalities. The number of teeth and incidence of abnormal root morphology in different genotypes of 13 SNPs were analyzed. RESULTS: The constituent ratio of root with root abnormality in GAgP patients was 14.49%(695/4 798). The average number of teeth with abnormal root morphology in GAgP was (3.88±3.84). The average number of teeth with abnormal root morphology in CC, CT and TT genotypes in vitamin D receptor (VDR) rs2228570 was (4.66±4.10), (3.71±3.93) and (2.68±2.68). There was significant difference between TT genotype and CC genotype (t = 2.62, P =0.01). The average number of root morphological abnormalities in CC, CT and TT genotypes of Calcitotin Receptor (CTR) gene rs2283002 was (5.02±3.70), (3.43±3.95), and (3.05±3.12). The incidence of root morphological abnormalities in CC genotype was higher than that in the patients with CT and TT, and the difference was statistically significant(87.86% vs. 65.26% & 63.64%, P=0.006, adjusted OR =3.71, 95%CI: 1.45-9.50). There was no significant difference in the incidence of abnormal root morphology between CT and TT genotypes. CONCLUSION: VDR rs2228570 and CTR rs2283002 may be associated with the occurrence of abnormal root morphology in patients with generalized aggressive periodontitis, which is worthy of further research.

[Tooth loss and multivariable analysis after 5-year non-surgical periodontal treatment on molars with furcation involvement].

OBJECTIVE: To evaluate the tooth loss status of mandibular molars with furcation involvements after 5-year non-surgical periodontal treatment, and to analyze the factors that affected the tooth loss. METHODS: A retrospective analysis was conducted in 79 patients with chronic periodontitis, who had received non-surgical periodontal treatment and 5 years of periodontal maintenance treatment in Department of Periodontology, Peking University School and Hospital of Stomatology from 1988 to 2012. Their clinical indexes, including probing depth (PD), bleeding index (BI), furcation index (FI) and tooth mobility were both evaluated before treatment and at the last time of the maintenance treatment. Bone resorption at furcation area was measured at the first visit by periapical radiographs taken by professional doctors of medical imaging. The status of tooth loss after 5-year non-surgical periodontal treatment on mandibular molars with furcation involvement, and the factors that affected the tooth loss were analyzed. RESULTS: (1) Non-surgical treatment was significantly effective on the changes of PD in the patients of chronic periodontitis with furcation involvement, while the presence of furcation involvement could affect the improvement of PD here. (2) PD at the furcation area, tooth mobility, vertical bone resorption, and bone resorption area were all significant risk factors of mandibular molar missing (P<0.001), and the same with FI=3 and FI=4 (P=0.017, P=0.007), while age (P=0.703), gender (P=0.243) and smoking history (P=0.895) were not related to the tooth loss in this study. (3) The risk of tooth loss in mandibular molars with FI≥3 were significantly higher than those with FI≤2, and the survival rate of the former was less than 50%. CONCLUSION: The loss of mandibular molars with furcation involvement was related to the furcation involvement, meanwhile the degree of furcation involvement and bone resorption can significantly increase the risk of tooth loss.

Effect of implant placement depth on the peri-implant bone defect configurations in ligature-induced peri-implantitis: An experimental study in dogs.

BACKGROUND: The subcrestal placement of implant platform has been considered a key factor in the preservation of crestal bone, but the influence of implant placement depth on bone remodeling combined with peri-implantitis is not fully understood. The aim of this study was to assess the effect of the crestal or subcrestal placement of implants on peri-implant bone defects of ligature-induced peri-implantitis in dogs. MATERIAL AND METHODS: Eight weeks after tooth extraction in six beagle dogs, two different types of implants (A: OsseoSpeed(TM), Astra, Molndal, Sweden; B: Integra-CP(TM), Bicon, Boston, USA) were placed at either crestal or subcrestal (-1.5 mm) positions on one side of the mandible. Ligature-induced peri-implantitis was initiated four weeks after the installation of the healing abutment connections. After 12 weeks, tissue biopsies were processed for histological analyses. RESULTS: Supra-alveolar bone loss combined with a shallow infrabony defect was observed in crestal level implants while deep and wide infrabony defects were present in subcrestal level groups. Subcrestal groups showed significantly greater ridge loss, depths and widths of infrabony defects when compared to crestal groups (P <0.001). CONCLUSIONS: Within the limitations of the animal study, it can be stated that the implants at subcrestal position displayed greater infra-osseous defect than implants at crestal position under an experimental ligature-induced peri-implantitis.

[Evaluation of using cone beam computed tomography as a regular test before and after periodontal regenerative surgery].

OBJECTIVE: To test the accuracy and credibility of cone-beam computed tomography (CBCT) on measuring the height and volume of alveolar bone defects before periodontal regeneration surgery. By comparing the bone density measured by CBCT before and after the operation, the time to evaluate the efficacy of the periodontal regenerative surgery would be determined. METHODS: Periodontal regenerative surgeries were performed on three-wall bone defects of ten teeth in nine patients. The height of bone defects was measured using both periapical film of distant parallel technique and CBCT before periodontal regenerative surgery. Before the surgery, CBCT data were used to measure the volume of the bone defects and the bone density around the defective areas. The height of the bone defects was measured during periodontal regeneration surgery, and the volume of the defective areas was obtained with bone wax in operation. CBCT was taken 6, 12 and 24 weeks after surgery to measure the bone density in the regenerated region. RESULTS: The Wilcoxon test showed that the height of the bone defects measured preoperatively using periapical film was (0.822±0.222) mm deeper than the intraoperative measurement results, and the difference was statistically significant (P<0.05). Whereas CBCT measurement results was (0.150±0.171) mm less than the intraoperative measurement results, without statistical significant (P>0.05). The regression analysis and the Bland-Altman method also showed that the results of CBCT measurement were more accurate. The Wilcoxon test showed that the bone defect volume measured by CBCT preoperatively was accurate, and the difference between the preoperative and the intraoperative measurements was not statistically significant, ranging from 0.38 to 2.83 mm3 (P>0.05). The bone density of the regenerated areas measured by CBCT was (0.49±0.03) times in the sixth week, (0.74±0.09) times in the twelfth week and (1.16±0.11) times in the twentieth week as that of the areas around the bone defects after the surgery. CONCLUSION: The present data suggest that using CBCT before periodontal regenerative surgery could result in accurate measurement of height and volume of alveolar bone defects. For the purpose of evaluating the effectiveness of regenerative surgery, CBCT could be taken 24 weeks after surgery.

[Influence of vitamin D receptor FokI polymorphism on expression of CYP24A1 in periodontal cells].

OBJECTIVE: There is asingle nucleotide polymorphism (SNP) in the exon 2 of the vitamin D receptor (VDR) gene that can be distinguished using the restriction endonuclease FokI, and accordingly divided into three genotypes: FF, Ff and ff. VDR-FokI polymorphism was the only known SNP that could alter the protein structure of VDR. CYP24A1 is the gene encoding vitamin D 24 hydroxylase and is a vitamin D responsive gene. The influence of rs2228570 on transcriptional activation by VDR in human gingival fibroblasts (hGF) and periodontal ligament cells (hPDLC) was investigated in this study. METHODS: hGF and hPDLC of 12 donors' were primarily cultured and genomic DNA was extracted. A part of genomic DNA with the length of 267 bp was obtained using PCR, which contained the SNP. VDR-Fok I genotypes were determined according to the results of restriction fragment length polymorphism. hGF and hPDLC were stimulated with 10 nmol/L 1α,25 dihydroxy vitamin D3 (1,25OH2D3) or 1 000 nmol/L 25 hydroxy vitamin D3 (25OHD3) for 48 h before RNA was extracted. Then VDR antagonist ZK159222 was used or not used during 1,25OH2D3 or 25OHD3 stimulation with hGF and hPDLC. After 1,25OH2D3 stimulation for 48 h, the proteins in hGF and hPDLC were also collected. The protein expressions of CYP24A1 and VDR were detected using Western blot. RESULTS: Among the 12 donors' cell cultures, the number of FF, ff and Ff genotypes was 4, 3 and 5, respectively.After stimulation with 1,25OH2D3 or 25OHD3 for 48 h,CYP24A1 mRNA levels in FF-hGF were significantly higher than those in other hGF genotypes(1,25OH2D3: F=31.147, P<0.01; 25OHD3: F= 32.061,P <0.01), as was in FF-hPDLC (1,25OH2D3: F=23.347, P<0.01; 25OHD3: F=32.569,P<0.01). When ZK159222 was used before 1,25OH2D3 stimulation, this statistically significant difference disappeared (hGF: F=0.246, P=0.787; hPDLC: F=0.574, P=0.583). When ZK159222 was used before 25OHD3 stimulation, the trend was similar (hGF: F=1.636, P=0.248; hPDLC: F=0.582, P=0.578).After stimulation with 1,25OH2D3 for 48 h, CYP24A1 protein levels in FF-hGF were significantly higher than those in the other hGF genotypes (F=12.368, P <0.01), as was in FF-hPDLC (F=15.749, P <0.01). In hGF and hPDLC, the mRNA or protein expression of VDR of different genotypes was not significantly different under different stimulation conditions.The paired comparison showed that there was no statistically significant difference between the expression of CYP24A1 in hGF and that in hPDLC under all the stimulation conditions, as was the expression of VDR. CONCLUSION: In hGF and hPDLC, the FF-VDR genotype is associated with the more remarkable up-regulation of CYP24A1than the other genotypes, indicating that transcriptional activation of FF-VDR might be higher than those of other vitamin D receptors.

[Clinical study of locking-taper implants in patients treated for periodontitis].

OBJECTIVE: To evaluate the survival rate and peri-implant clinical parameters of Locking-Taper implants in patients having lost their teeth due to non-periodontitis (NP) reasons, chronic periodontitis (CP) and aggressive periodontitis (AgP). METHODS: In the study, 145 subjects were installed with 315 Bicon Locking-Taper implants and followed up for 1-5 years. The subjects and implants were classified into three groups, tooth loss by NP, CP and AgP. NP included 44 subjects with 100 implants, CP 70 subjects with 132 implants and AgP 31 subjects with 83 implants. Periodontal parameters before subgingival scaling and root planning (T0), at the end of active periodontal therapy (T1) and at the time of last recall (T2) were recorded. Right after the installation of final restoration and at the time of last recall (T2), peri-implant probing parameters were recorded. RESULTS: After active periodontal therapy, mean probing depth (PD) in CP and AgP were reduced from 4.05 mm, 5.20 mm at T0 to 3.07 mm, 2.96 mm at T1 (P<0.001, P<0.001), (PD≥6 mm)% were reduced from 33.2%, 58.5% at T0 to 14.4%, 10.5% at T1 (P<0.001, P<0.001). The periodontal parameters remained stable at T2 compared with T1 (P>0.05). Cumulative survival rates of implants in NP, CP and AgP were 100%, 97.6% and 100% for 1-5 years' follow-ups with no statistical significance found. At T2, mean implant PD was 2.78 mm, 2.96 mm and 2.97 mm in NP, CP and AgP, with NP significantly lower than the other two groups (P=0.006, P=0.01). The percentage of implant sites with PD≥6 mm was 3.7% in CP and 4.8% in AgP, both significantly higher than NP (P=0.003, P<0.001). 8.4% implant sites showed at least 2 mm deeper than those at prosthesis installation were found in CP group, significantly higher than NP (4.3%, P=0.003). CONCLUSION: Periodontal conditions of patients having lost their teeth for chronic and aggressive periodontitis were significantly improved after active periodontal therapy and remained stable during 1-5 years. Short-term survival rates of Locking-Taper implants in patients treated for CP and AgP was no less than those who lost their teeth for non-periodontitis reasons. More sites with increasing peri-implant probing depth were found in CP and AgP patients, compared with NP.

Vitamin D-binding protein expression in healthy tooth and periodontium: an experimental study both in monkeys in vivo and in humans in vitro.

BACKGROUND AND OBJECTIVE: Vitamin D-binding protein (DBP) is a highly expressed plasma protein with many important functions, including transport of vitamin D metabolites, sequestration of actin, control of bone metabolism and modulation of immune and inflammatory responses. Previous results of our study indicated an association between DBP and periodontitis. We hypothesized that periodontium might be another source of DBP in gingival crevicular fluid other than serum. MATERIAL AND METHODS: DBP expression was examined in dental and periodontal tissues of monkeys by immunohistochemistry, and in primary cells isolated from human dental and periodontal tissues by reverse transcription plus the polymerase chain reaction and immunocytochemistry. RESULTS: DBP was constitutively expressed and widely distributed in dental and periodontal tissues of primates. Their immunoreaction was evident in gingival epithelium, particularly in junctional epithelium, and in mineralizing areas of the dental pulp, periodontal ligament and bone marrow. Correspondingly, mRNA and protein expression were detected in primary human gingival epithelial cells, dental pulp cells and periodontal ligament cells. CONCLUSION: DBP is highly expressed and widely distributed in dental and periodontal tissues, which may take an active part in local host defense and hard tissue metabolism.

Proinflammatory effects and mechanisms of calprotectin on human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Calprotectin (S100A8/A9) is a heterodimer of S100A8 and S100A9 and is associated with multiple inflammatory diseases, including Crohn's disease, rheumatoid arthritis and periodontitis. Levels of calprotectin are elevated in the gingival crevicular fluid of patients with periodontitis; however, the effects of calprotectin on human gingival fibroblasts (HGFs) remain unknown. This study investigated the proinflammatory activity of calprotectin on HGFs and the functional receptors and signaling pathways engaged by calprotectin. MATERIAL AND METHODS: HGFs were stimulated by equimolar concentrations of S100A8 and/or S100A9, and the expression levels of interleukin (IL)-6 and IL-8 were detected using real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assays. The calprotectin receptors were identified by pre-incubating HGFs with the toll-like receptor (TLR) 4 inhibitor or the antibody targeting the advanced glycation end product receptor (RAGE). The involvement of reactive oxygen species (ROS) and signaling pathways were also investigated by treating HGFs with ROS inhibitor or specific pathway inhibitors, respectively. RESULTS: S100A9 and S100A8/A9 significantly upregulated IL-6 and IL-8 expression, which was inhibited upon treatment with the TLR4 inhibitor TAK242. Pretreatment with RAGE-blocking antibodies did not affect cytokine expression. Additionally, S100A9 promoted the production of IL-6 and IL-8 from HGFs via different signaling pathways. IL-6 expression was upregulated via the NF-κB, c-Jun amino-terminal kinase (JNK) 1/2 and p38 mitogen-activated protein kinase (MAPK) pathways, and IL-8 expression was upregulated via NF-κB, p38, JNK1/2 and extracellular-regulated kinase 1/2 MAPK pathways. The release of both cytokines was dependent upon the production of ROS. CONCLUSION: Our findings suggest that calprotectin exerts proinflammatory effects on HGFs via the S100A9 subunit and TLR4-mediated NF-κB and MAPK signaling pathways.

[Clinical evaluation of periodontal-orthodontic treatment in patients with aggressive periodontitis and malocclusion].

OBJECTIVE: To evaluate the clinical effect and safety of periodontal-orthodontic treatment in patients with aggressive periodontitis (AgP) and malocclusion. METHODS: A retrospective analysis was conducted in 25 AgP patients, who had received periodontal-orthodontic treatment in Peking University School and Hospital of Stomatology. Clinical indexes, including probing depth (PD), bleeding index (BI) and percentage of sites with bleeding on probing (BOP%) were evaluated at three time points: Baseline (T0); active periodontal treatment finished and before orthodontic treatment (T1); and after orthodontic treatment (T2). Also changes of ratio of the residual alveolar bone height (RBH) and the occurrence of root resorption were evaluated by periapical radiographs. RESULTS: (1) Compared with T0, all the clinical parameters including PD, BI, BOP% and percentage of sites with PD>3 mm were significantly improved (P<0.001). (2) Significant difference was observed in the average RBH between T0 (68.37%±15.60% and T2 (70.27%±14.23%). RBH in upper incisors [(58.79%±16.71% at T0, 65.54% (55.74%, 78.13%) at T2], upper canines [77.62% (66.06%, 87.17%) at T0, 79.57% (69.75%, 86.52%) at T2] and upper molars [74.30% (61.69%, 84.45%) at T0, 76.76% (68.12%, 85.09%) at T2] showed significant increase (P<0.05). (3) After orthodontic treatment, varying degrees of root resorption occurred in (23.94%±13.45%) of teeth per capita, among which the lower and upper incisors showed the highest incidence (68.48% and 65.31% in homogeneous teeth, respectively). CONCLUSION: After active periodontal treatment, orthodontic treatment in AgP patients had not aggravated inflammation and alveolar bone resorption; root resorption occurred in two-thirds of incisors approximately.

[An modified culture method of primary human gingival epithelial cells].

OBJECTIVE: To establish a stable primary culture method of human gingival epithelial cells, with a higher successful rate and shorter culture time. METHODS: Nine patients who received "crown-lengthening surgery" with relatively healthy periodontal conditions were selected (n=9). Gingival samples were collected from the 9 donors during gingivectomy. Gingival epithelial cells were isolated and cultured by both an advanced enzyme digestion method and a tissue explant method. In the advanced enzyme digestion culture process, 2.5 g/L DispaseIIwas used to separate the epithelial tissue part from the connective tissue part, which lasted for one night. Then the epithelial tissues were digested by 0.025% trypsin without EDTA for 10 minutes, and centrifuged by keeping the digested epithelial tissues that remained. This advanced method not only decreased the concentration and digesting time of the two above-mentioned enzymes, but also simplified the centrifugel process. The tissue explant method was not changed too much compared with the original method. Growing processes of the primary cells cultured by the two methods were observed and recorded respectively, and indirect immunocytochemical staining was used to identify the type of cultured cells. At the same time, successful rates and cell culture time were also compared between the two methods. RESULTS: Human gingival epithelial cells with typical morphology could be cultured within a shorter period by the advanced enzyme digestion method with a successful rate of 88.9%, and proliferated rapidly as sheets. After 10-14 d cells could be passaged, gradually turned to be like fibroblasts when passaged to the third generation, and eventually went to apoptosis. The primary culture time was longer by using the tissue explant method, and approximately after 17-22 d cells could be passaged, although the successful rate was the same as the enzyme digestion method. Cytokeratin staining was both positive by indirect immunocytochemical staining of cells. CONCLUSION: Primary human gingival epithelial cells cultured by the advanced enzyme digestion method could grow faster and be passaged to the second generation successfully, which could supply a stable origin for cellular experiments.

[An modified culture method of primary human gingival epithelial cells].

OBJECTIVE: To establish a stable primary culture method of human gingival epithelial cells, with a higher successful rate and shorter culture time. METHODS: Nine patients who received "crown-lengthening surgery" with relatively healthy periodontal conditions were selected (n=9). Gingival samples were collected from the 9 donors during gingivectomy. Gingival epithelial cells were isolated and cultured by both an advanced enzyme digestion method and a tissue explant method. In the advanced enzyme digestion culture process, 2.5 g/L DispaseIIwas used to separate the epithelial tissue part from the connective tissue part, which lasted for one night. Then the epithelial tissues were digested by 0.025% trypsin without EDTA for 10 minutes, and centrifuged by keeping the digested epithelial tissues that remained. This advanced method not only decreased the concentration and digesting time of the two above-mentioned enzymes, but also simplified the centrifugel process. The tissue explant method was not changed too much compared with the original method. Growing processes of the primary cells cultured by the two methods were observed and recorded respectively, and indirect immunocytochemical staining was used to identify the type of cultured cells. At the same time, successful rates and cell culture time were also compared between the two methods. RESULTS: Human gingival epithelial cells with typical morphology could be cultured within a shorter period by the advanced enzyme digestion method with a successful rate of 88.9%, and proliferated rapidly as sheets. After 10-14 d cells could be passaged, gradually turned to be like fibroblasts when passaged to the third generation, and eventually went to apoptosis. The primary culture time was longer by using the tissue explant method, and approximately after 17-22 d cells could be passaged, although the successful rate was the same as the enzyme digestion method. Cytokeratin staining was both positive by indirect immunocytochemical staining of cells. CONCLUSION: Primary human gingival epithelial cells cultured by the advanced enzyme digestion method could grow faster and be passaged to the second generation successfully, which could supply a stable origin for cellular experiments.

[Modified percutaneous vertebroplasty assisted by preoperative CT-based digital design: a new technique for osteoporotic vertebral compression fracture].

OBJECTIVE: To report a new technique of modified percutaneous vertebroplasty (PVP) assisted by preoperative CT-based digital design for osteoporotic vertebral compression fracture (OVCF), and to discuss its preliminary clinical results. METHODS: Thoracolumbar spine segment data (Dicom format) were obtained from lamellar CT scanning of seven old female or male with single OVCF. A three-dimensional model of thoracolumbar spine and simulative PVP models (via double transpedicular approach) were built in the Mimics software. With the help of a preoperative transparent marker located at the back midline skin and preoperative digital design by Mimics software, the needle insert point and needle direction in every patient were established. The surgical time, the number of intraoperative radiation perspective, bone cement filling condition in fracture vertebra, intraoperative complications and visual analogue scale (VAS) scores before and after surgery were recorded to evaluate the preliminary clinical results after modified PVP. RESULTS: The puncture process during PVP was in high accordance with the preoperative digital design by Mimics software in seven cases of single OVCF with the average age of 78 years old. The operation time was only 16.57±2.07 minutes and the intraoperative radiation perspective numbers were less than ten (7.86±1.68) times. The bone cement filling in all fracture vertebras were good and no surgical complications such as spine cord injury and cement leakage were founded. The VAS scores before and after surgery were 8.57±0.53 points and 1.43±0.53 point (P=0.000), respectively. CONCLUSION: Percutaneous vertebroplasty (PVP) assisted by preoperative CT-based digital design has high accuracy, which is expected to reduce operation time, intraoperative radiation exposure and the surgical complications related to puncture failure.

Associations of apolipoprotein E and low-density lipoprotein receptor-related protein 5 polymorphisms with dyslipidemia and generalized aggressive periodontitis in a Chinese population.

BACKGROUND AND OBJECTIVE: Dyslipidemia is associated with aggressive periodontitis, a condition characterized by the rapid destruction of the periodontium. Apolipoprotein E (APOE) and low-density lipoprotein receptor-related protein 5 (LRP5) are involved in immunomodulation and inflammatory activity. We evaluated the association of LRP5 and APOE polymorphisms with serum lipid concentrations and generalized aggressive periodontitis within a Chinese population. MATERIAL AND METHODS: Mean serum lipid concentrations were compared across LRP5 and APOE polymorphisms, among cases (n = 185) and controls (n = 138). Multivariable logistic regression was used to evaluate the independent and combined associations of LRP5 and APOE polymorphisms with generalized aggressive periodontitis. RESULTS: Compared with controls, individuals with generalized aggressive periodontitis exhibited significantly lower serum total cholesterol (TC) and lower high-density lipoprotein cholesterol (HDL-c). Individuals with LRP5 polymorphisms (rs682429-AA or rs312016-GG) exhibited higher TC, higher HDL-c and decreased odds for generalized aggressive periodontitis. Haplotype (A-G), determined by rs682429 and rs312016, was also associated with decreased odds for generalized aggressive periodontitis. Furthermore, individuals with the combined polymorphisms (LRP5-rs682429-AA and APOE-rs429358-CC/CT) had higher levels of low-density lipoprotein cholesterol, higher levels of TC and decreased odds for generalized aggressive periodontitis. CONCLUSION: Independently or combined with APOE, LRP5 polymorphisms may lead to dyslipidemia and are associated with generalized aggressive periodontitis. Dyslipidemia may be a risk indicator for generalized aggressive periodontitis in the Chinese population. Furthermore, two LRP5 polymorphisms (rs682429 and rs312016) might be useful for identifying subjects at higher risk of generalized aggressive periodontitis.