Multivariable analysis of tooth loss in subjects with severe periodontitis over 4-year natural progression / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the characteristics of severe periodontitis with various number of tooth loss during 4-year natural progression, and to analyze the factors related to higher rate of tooth loss.@*METHODS@#A total of 217 patients aged 15 to 44 years with severe periodontitis were included, who participated in a 4-year natural progression research. Data obtained from questionnaire survey, clinical examination and radiographic measurement. Tooth loss during 4-year natural progression was evaluated. The baseline periodontal disease related and caries related factors were calculated, including number of teeth with bone loss > 50%, number of missing molars, number of teeth with widened periodontal ligament space (WPDL), number of teeth with periapical lesions and etc. Characteristics of populations with various number of tooth loss and the related factors that affected higher rate of tooth loss were analyzed.@*RESULTS@#In 4 years of natural progression, 103 teeth were lost, and annual tooth loss per person was 0.12±0.38. Nine patients lost 3 or more teeth. Thirty-four patients lost 1 or 2 teeth, and 174 patients were absent of tooth loss. Molars were mostly frequent to lose, and canines presented a minimum loss. The number of teeth with WPDL, with periapical lesions, with intrabony defects, with probing depth (PD)≥7 mm, with PD≥5 mm, with clinical attachment loss≥5 mm, with bone loss > 50% and with bone loss > 65% were positively correlated to number of tooth loss. Results from orderly multivariate Logistic regression showd that the number of teeth with bone loss > 50% OR=1.550), baseline number of molars lost (OR=1.774), number of teeth with WPDL (1 to 2: OR=1.415; ≥3: OR=13.105), number of teeth with periapical lesions (1 to 2: OR=4.393; ≥3: OR=9.526) and number of teeth with caries/residual roots (OR=3.028) were significant risk factors related to higher likelihood of tooth loss and multiple tooth loss.@*CONCLUSION@#In 4 years of natural progression, the number of teeth with bone loss > 50%, baseline number of missing molars, number of teeth with WPDL, baseline number of teeth with periapical lesions and number of teeth with caries/residual roots were significantly related to higher risk of tooth loss and multiple tooth loss among Chinese young and middle-aged patients with severe periodontitis in rural areas.

Effect of verapamil on the proliferation of normal gingival fibroblast / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of verapamil on the proliferation of normal gingival fibroblast (NGF) in vitro.</p><p><b>METHODS</b>NGF was isolated and cultured. The 5th passage of NGF was incubated with 0, 0.1, 1, 10, 100 micromol/L verapamil respectively. Methyl thiazolyl tetrazolium (MTT) assay and flow cytometry were used to detect cell proliferation and cell cycles.</p><p><b>RESULTS</b>Incubated with 100 micromol/L verapamil for 66 h, the A value of normal gingival fibroblast was significantly lower than those without verapamil groups (P < 0.01). Incubated with 100 micromol/L verapamil for 18 h, 69% of cells were at the G(0) - G(1) phase, 27% were at the S phase. For control group (without verapamil) 41% of cells were at G(0) - G(1) phase and 49% cells were at S phase. There was significant difference between the two groups (P < 0.001).</p><p><b>CONCLUSIONS</b>100 micromol/L verapamil inhibited proliferation of normal gingival fibroblast by a cell-cycle arrest.</p>

Effects of enamel matrix protein on the growth of human periodontal ligament cells on root cementum surfaces / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of enamel matrix protein (EMP) on the attachment and proliferation of periodontal ligament cells (PDLC) on diseased cementum surfaces in vitro.</p><p><b>METHODS</b>Cementum chips were obtained from diseased roots exposed to periodontal pocket. Thirteen diseased root cementum chips were conditioned with EMP. Meanwhile, 13 diseased and 13 healthy cementum chips were treated with physiological saline as control. The growth and morphology of PDLC on the root surface were observed after 24 hours incubation by scanning electron microscope (SEM). PDLC attachment and proliferation were quantified using MTT assay at 16 or 72 hours.</p><p><b>RESULTS</b>The cells on EMP treated roots under SEM were growing robust like the cells on healthy roots. By contrast, the diseased cementum surface without conditioned with EMP was only partly covered with spindle-shaped cells, with filopodia appearing short and thin. MTT assay indicated that the number of adhered and proliferated cells on diseased cementum chips treated with EMP was significantly greater than that on diseased chips treated with saline (adhesion: 0.45 +/- 0.03 vs. 0.37 +/- 0.05, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 0.55 +/- 0.08, P < 0.01), but less than that on healthy chips (adhesion: 0.45 +/- 0.03 vs. 0.67 +/- 0.08, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 1.05 +/- 0.09, P < 0.05).</p><p><b>CONCLUSIONS</b>It was suggested that EMP could promote the growth of PDLC on the diseased root cementum surface.</p>

Novel mutations of cathepsin C gene in two Chinese patients with Papillon-Lefèvre syndrome / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the mutational characteristics of cathepsin C (CTSC) gene in two Chinese patients with Papillon-Lefèvre syndrome (PLS), and provide molecular basis for research of the pathogenesis of PLS.</p><p><b>METHODS</b>Peripheral blood samples were obtained from patients and their parents respectively. Genomic DNA were extracted after consents. Polymerase chain reaction, direct DNA sequencing and restriction enzyme reaction were performed to screen mutations of CTSC gene.</p><p><b>RESULTS</b>Compound heterozygous mutations of CTSC gene were identified in the two patients. Patient I carried the G139R and S260P mutations, patient II had the R250X and C258W mutations. The parents were heterozygous carriers without the clinical feature of PLS. None of the mutations were detected in normal controls. Furthermore, the S260P and C258W changes were novel mutations of CTSC gene, which had not been reported previously.</p><p><b>CONCLUSIONS</b>Mutations of CTSC gene are responsible for the phenotype of Papillon-Lefèvre syndrome in two Chinese patients. The results extend the mutation spectrum of CTSC gene and also provide basis for gene diagnosis of PLS in China.</p>

The p16 methylation in oral leukoplakia and oral squamous cell carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate p16 gene methylation in normal mucosa, leukoplakia with hyperplasia and dysplasia and oral squamous cell carcinoma.</p><p><b>METHODS</b>20 patients of leukoplakia with hyperplasia, 11 patients of leukoplakia with mild dysplasia, 10 patients of leukoplakia with moderate dysplasia, 9 patients of leukoplakia with severe dysplasia, 10 patients with OSCC in low grade, 12 patients with OSCC in moderate grade, 8 patients with OSCC in high grade, and 10 normal individuals were studied on p16 methylation.</p><p><b>RESULTS</b>Rates of p16 methylation were 0 for normal individuals, 5% for patients of leukoplakia with hyperplasia, 18% for patients of leukoplakia with mild dysplasia, 10% for patients of leukoplakia with moderate dysplasia, 22% for patients of leukoplakia with moderate dysplasia, and 50% for patients with OSCC in low grade, 42% for patients with OSCC in moderate grade, and 63% for patients with OSCC in high grade. Rates of p16 methylation increased with tissue malignance increase and correlated positively to the tissue malignance. The rate (82%) of p16 methylation in OSCC patients with lymph node metastasis was significantly high than that (32%) of OSCC patients without lymph nodes metastasis. The methylated rates of p16 correlated positively to the lacking rates of p16 protein.</p><p><b>CONCLUSIONS</b>It was first reported that p16 methylation occurred in every stage of leukoplakia cancerization and OSCC progression. p16 can be one of the important molecular biological markers for leukoplakia cancerization and OSCC progression. p16 methylation is recommended as an important marker for diagnosis of OSCC.</p>

Two-year disease progression in mild, moderate and advanced chronic periodontitis patients / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe two-year natural progression of chronic periodontitis in mild, moderate and advanced periodontitis patients.</p><p><b>METHODS</b>The periodontal status of 169 untreated chronic periodontitis patients aged from 22 to 64, were examined for two years. Periodontal measurements were performed on all teeth except the third molars and 6 sites examined for each tooth. Probing depth (PD), attachment loss (AL), and bleeding on probing (BOP) were measured at baseline, one year, and two year by a same experienced periodontist. Forty-five patients were diagnosed as having mild periodontitis, 87 with moderate, and 37 with advanced periodontitis. The changes of attachment level in these three group patients were analyzed. The site with change of AL greater than 3 mm (DeltaAL > or = 3 mm) were defined as periodontal disease activity (PDA) sites. The occurrence of PDA in three groups was compared.</p><p><b>RESULTS</b>(1) The average AL levels at 1 year and at 2 year were greater than that at baseline in mild, moderate and advanced periodontitis. (2) The percentage of sites with AL > or = 1 mm in three groups all increased from baseline to 1 year and to 2 year. (3) The occurrence of periodontal disease activity increased significantly from mild (0.14% at site level, 15.56% at subject level), moderate (0.39%, 29.89%) to advanced (0.73%, 43.24%) periodontitis patients. (4) The mean baseline AL and PD levels in active sites were greater than that in inactive sites (PD: 3.03 +/- 0.45 vs. 2.87 +/- 0.38, P < 0.05; AL: 2.25 +/- 0.93 vs. 1.77 +/- 0.90, P < 0.01).</p><p><b>CONCLUSION</b>Untreated advanced periodontitis patients were the risk population for further periodontal breakdown.</p>

The in vivo formation of cementum-like tissue by bovine cementoblasts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To test the bovine cementoblasts (CBs) cementum-forming ability in vivo.</p><p><b>METHODS</b>Root fragments of newborn bovine freshly extracted mandibular incisor were cultured routinely and 4th-5th passages of CBs were harvested. CBs were then cultured in the medium supplemented with 50 mg/L alpha-ascorbic acid and 10 mmol/l beta-glycerolphosphate to form a thick layer as tissue engineering scaffold for cementum formation. Collagen membrane was used as control scaffold. 2 x 10(6) cells were attached to the CBs-made carrier as well as collagen membrane scaffolds and transplanted subcutaneously into immunodeficient mice. Transplants were harvested at 7th week. Histological sections were stained with HE, alizarin red S and van Kossa methods as well as monoclonal Ab against bovine cementum attachment protein (CAP).</p><p><b>RESULTS</b>CBs-made scaffold supported more cementum-like tissue (CLT) formation than collagen-made scaffold. The CLT formed on CBs scaffold was partly calcified with embedded cells. Uncalcified cementoid-like material could be seen on the surface and was encircled by cubical CB-like cells. The CLT was also positive to CAP and van Kossa staining.</p><p><b>CONCLUSIONS</b>These results suggest that the bovine CBs can form cementum-like tissue. The cell-made carrier is a better scaffold than collagen membrane.</p>

Analysis on oral health care utilization and expenditure of residents in Beijing / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To analyze the dental care utilization and expenditure of residents in Beijing, and to provide some basis on the policy of oral health insurance system.</p><p><b>METHODS</b>A cross-sectional survey was conducted among 1,517 subjects (urban area) and 1,878 subjects (rural area) of all age groups in Beijing selected by stratified, clustering, random sampling. The data of oral health care utilization and expenditure were collected in their home.</p><p><b>RESULTS</b>The number of the people who visited a dentist in a year were low both in urban area and in rural area, but the expenditure for oral health care per visit were quite high. The value of utilization of dental care in rural residents was 1/3 of that in urban residents, while the value of expenditure in rural people was about 1/2 of that in urban people. 2.07% incomes of rural residents were used for dental care per year, the corresponding value of urban residents was 1.77%. There was significant difference on the expenditure among those with different demographic, socio-economic backgrounds.</p><p><b>CONCLUSIONS</b>The expenditure for oral health care was high in Beijing, which accounted for quite a lot in average incomes per year. The burden of expenditure for dental care on rural residents was heavier than that on urban residents. The level of expenditure for dental care could provide some references for oral health insurance system in Beijing.</p>

Effect of chewing sugar-free gum after sucrose challenge on dental plaque pH in situ / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of chewing sugar-free gum after sucrose challenge on dental plaque pH in situ.</p><p><b>METHODS</b>16 healthy volunteers aged 23 - 32 years were screened as subjects. The pH of 48-hour dental plaque was measured using a Beetrode pH microelectrode when subjects chewed Extra sugar-free gum after sucrose challenge.</p><p><b>RESULTS</b>Dental plaque pH maintained at resting plaque pH when immediately chewed sugar-free gum after sucrose challenge. Chewing sugar-free gum at 5 min after sucrose challenge, dental plaque pH was raised from 5.59 (measured at 5 min after sucrose challenge) to 6.98 (measured at 10 min after sucrose challenge).</p><p><b>CONCLUSIONS</b>Chewing sugar-free gum after sucrose challenge can neutralize organic acid produced by bacteria in dental plaque and rapidly rise plaque pH.</p>