Exploration and practice of Peking University Model to improve the clinical teaching effect of clinical postgraduates majoring in periodontology / 中华口腔医学杂志

The number of patients with periodontal disease in China is large, and the ratio of doctors to patients is seriously imbalanced, especially in the insufficient number of periodontal specialists and periodontal teachers. Strengthening the cultivation of professional postgraduates in periodontology can effectively solve this problem. This paper summarizes the experiences of Peking University School and Hospital of Stomatology in the teaching of periodontal postgraduate students for more than 30 years, in cluding teaching objectives formulation, teaching resources allocation and enhancement of the quality control system of clinical teaching, for ensuring that the periodontal professional postgraduates could reach the expected level after training. This formed the current "Peking University Model". There are both opportunities and challenges in clinical teaching of periodontal postgraduates in domestic stomatology community. The authors hope that the continuous exploration and improvement of this teaching system will promote the vigorous development of clinical teaching for the postgraduates majoring in periodontology in China.

The histopathological characteristics of peri-implantitis / 中华口腔医学杂志

Peri-implantitis (PI) has been defined as an inflammatory lesion of the mucosa surrounding an endosseous implant and with progressive loss of supporting peri-implant bones. In recent years, histopathological differences between PI and periodontitis of natural teeth had been described in animal experiments and a certain number of human experiments. In this paper, we review the histopathological differences between PI and periodontitis reported in the existing literature and try to find the differences in the occurrence and progression of these two diseases. Overall, inflammatory cell infiltrate (ICT) is more extensive in PI than in periodontitis, extending to the alveolar ridge, with dense infiltration of plasma cells, lymphocytes, macrophages, polymorphonuclear leukocytes and a greater number of osteoclasts in the connective tissue, but with less vascular density within ICT than in periodontitis. In addition, foreign bodies are found in PI lesions. The histopathological differences between the two diseases in terms of inflammatory infiltration, vascularity, bone loss, and foreign bodies could partially explain the more rapid progression of PI than periodontitis, suggesting that PI should be taken seriously by physicians. Early diagnosis and treatment are essential to control the progression of PI. In addition, targeted therapy against specific inflammatory cells may become a new direction for PI treatment; reducing titanium particles released into peri-implant tissue by friction or electrochemical corrosion may help to prevent PI.

Gene polymorphisms of cytochrome B-245 alpha chain (CYBA) and cholesteryl ester transfer protein (CETP) and susceptibility to generalized aggressive periodontitis / 北京大学学报(医学版)

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.

The accuracy of probing depth measurements of undergraduate students and associated factors analysis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the accuracy of probing depth measurements of undergraduate students in department of periodontology and analyze the cause of measurement errors.</p><p><b>METHODS</b>Thirty-eight dental students from Peking Universty School and Hospital of Stomatology who began their periodontal clinical practice for the first time were recruited. According to principle of clinical teaching, after the students recorded the probing depth of 1-2 periodontitis patients using Williams periodontol probe, an experienced teacher checked the probing depth. The measurements of interproximal sites of Ramfjord index teeth (6 14 41 6) were used as the data of this study. According to the probing depth discrepancies between teacher and the students, all the probing sites were divided in three levels: absolutely consistent sites (probing depth measured by teacher and by student was completely consistent), almost consistent sites (the depth discrepancy between teacher and student was 1 mm), inconsistent sites (the depth discrepancies between teacher and student ≥ 2 mm).</p><p><b>RESULTS</b>The accuracy of probing depth measurements of students decreased with the deepening of probing depth, and the accuracy of probing depth measurements in molar teeth was significantly lower than incisor teeth [58.8% (261/444) vs.73.1% (339/464), P < 0.01]. The main factor associated with the accuracy of probing depth measurements in interproximal sites was the probe's inability to get into gingival col, which accounted for 70.7% (87/123) of the total inconsistent sites.</p><p><b>CONCLUSIONS</b>The correct angle of insertion of the probe in interproximal sites should be reinforced during the course of pre-clinical education of periodontal probing. More attention should be paid to check the probing depth of deep pockets and molar teeth during the clinical practice of undergraduate students.</p>

Alveolar bone loss in nuclear families of aggressive periodontitis and the heredity of root shape / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the status of residual alveolar bone in aggressive periodontitis (AgP) nuclear families and to investigate the influence of teeth with root abnormity on residual alveolar bone and the heredity of root abnormity, the premolar cone-root and proportion of crown and root.</p><p><b>METHODS</b>Nineteen AgP probands (9 males and 10 females) at average age of 24.5 and 38 parents at average age 51.0 were included. A full set of periapical radiographs of all the subjects were taken. The residual alveolar bone of each tooth was measured by the ratio (shown as percentage) of the distance between apical and the alveolar bone crest to the whole root length. The abnormity of roots was detected on a full set of periapical radiographs. All the roots and crowns of teeth were measured. The relationship between the residual bone and the ratio was studied. The heredity grade of the premolar cone-root, proportion of crown and root, and root abnormity were computed.</p><p><b>RESULTS</b>The average residual alveolar bone of probands was less than that of their parents.In 11 families, the father's residual alveolar bone was less than that of the mother's. The average residual alveolar bone of the teeth with root abnormity was less than that of normal teeth. The average residual alveolar bone of the teeth with abnormity of roots and the normal teeth were (67.5 ± 22.2)% and (73.1 ± 18.7)% respectively, with statistical significance (P < 0.001). The heredity grade of the premolar cone-root was 40.1%, the heredity grade of proportion of crown and root was 46.8%, the heredity grade of root abnormity was 30.3%.</p><p><b>CONCLUSIONS</b>The residual alveolar bone of the teeth with root abnormity was less than that of normal teeth in nuclear families. The heritability of the root abnormity, the cone-root and proportion of crown and root in our sample was 0.3-0.5, which means that genetic factors accounted for about one third to half of the efficiency for AgP.</p>

A preliminary study on the genetic mode of aggressive periodontitis in Chinese Han nationality / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the potential genetic mode of aggressive periodontitis (AgP) in Chinese Han nationality.</p><p><b>METHODS</b>A total of 233 subjects from 73 nuclear families were recruited. All probands were diagnosed according to the criteria of AgP in 1999 classification of periodontal diseases. Ninety parents, 35 siblings and three grandparents and two offspring were examined based on full-mouth periodontal chartings (including parameter of probing depths, attachment loss, bleeding on probing at six sites per tooth) and full-mouth periapical radiographs. The genetic ratio was calculated and analyzed by the methods of Edwards and simple segregation.</p><p><b>RESULTS</b>The prevalence of AgP in probands' siblings was close to the square root of the prevalence of general population. The segregation ratio was 0.2419, which was close to the theoretical ratio for autosomal recessive inheritance. However, autosomal dominant inheritance could not be rejected in families whose parent(s) suffered from severe chronic periodontitis.</p><p><b>CONCLUSIONS</b>The genetic heterogeneity of AgP existed in Chinese Han nationality. The genetic mode was autosomal recessive inheritance in general, and autosomal dominant inheritance could not be excluded in families whose parent(s) suffered from severe chronical periodontitis. The results imply the genetic heterogeneity of AgP, and further demonstrate that AgP was a multifactorial disease with major genetic component in the disease etiology.</p>

Short term effect of combined use of amoxicillin and metronidazole at different time of non-surgical periodontal treatment for aggressive periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the short term clinical results of scaling and root planning (SRP) only, SRP combined with amoxicillin (AMX) and metronidazole (MTZ) after supragingival scaling or after SRP in the treatment of aggressive periodontitis (AgP).</p><p><b>METHODS</b>A total of 45 patients with AgP were randomly divided into SRP group, SRP with AMX + MTZ after supragingival scaling group and AMX + MTZ after SRP group. Subgingival scaling and root planning were performed one week after supragingival scaling and finished within 1 month. AMX and MTZ were given for 7 days immediately after supragingival scaling or the last time of SPR. Clinical examinations including probing depth (PD), attachment level (AL) and bleeding index (BI) were performed at baseline and 8 weeks after non-surgical periodontal treatment by the same examiner.</p><p><b>RESULTS</b>There were more PD reduction and AL gain in both AMX + MTZ after supragingival scaling group and AMX + MTZ after SRP group compared with SRP group [2.5 (1.8, 3.3) mm, 2.3 (1.9, 2.7) mm vs. 1.8 (1.3, 2.1) mm, P < 0.05]; [0.9 (0.5, 1.4) mm, 0.8 (0.4, 1.3) mm vs. 0.4 (0.2, 1.0) mm, P < 0.05]. In sites PD ≥ 7 mm, PD reduction was more in AMX + MTZ after supragingival scaling group than AMX + MTZ after SRP group [4.0 (3.0, 5.0) mm vs. 4.0 (3.0, 4.0) mm, P < 0.05)].</p><p><b>CONCLUSIONS</b>The combined use of AMX and MTZ during non-surgical periodontal treatment for patients with AgP was effective in short term. In patients with most sites PD ≥ 7 mm, AMX and MTZ could be taken after supragingival scaling, but the long-term clinical effects needs further investigation.</p>

Effect of periodontal mechanical treatment on herpesviruses in gingival crevicular fluid of patients with chronic periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the subgingival prevalence of human cytomegalovirus (HCMV), Epstein-Barr virus-1 (EBV-1) in chronic periodontitis (CP) patients before and after treatment and to analyze the relationship between the prevalent variance and periodontal clinical parameters.</p><p><b>METHODS</b>Gingival crevicular fluids of 13 CP patients were collected at baseline, 2 weeks, 2 months and 4 months after periodontal mechanical treatment. HCMV and EBV-1 were detected using nested polymerase chain reaction (n-PCR).</p><p><b>RESULTS</b>The plaque index (PLI), probing depth (PD) and bleeding index (BI) of CP patients at 2 months, 4 months after periodontal mechanical treatment were evidently lower than before treatment, P < 0.01. These parameters at 4 months after treatment were higher than at 2 months, the differences were significant, P < 0.05. The prevalence of HCMV and EBV in CP patients was 42% (33/78), 14% (11/78). EBV and HCMV were mostly coexistent in the same site [9 sites HCMV(+) in 11 EBV positive sites]. The sites of HCMV(+) and EBV(+) were almost deep pockets. Thirteen of 14 sites with deep pockets were HCMV(+), 9 sites were deep pockets in 11 sites EBV(+). The prevalence of HCMV and EBV (8% and 0 respectively) at 2 weeks was the lowest in all four time points. The prevalence of HCMV and EBV at 2 weeks, 2 months and 4 months following treatment was significantly lower than baseline (P < 0.01), but the prevalence of HCMV (15%) at 2 months after treatment was higher than at 2 weeks (8%), the difference was not significant (P = 0.133).</p><p><b>CONCLUSIONS</b>Herpesviruses may play a role in the development of CP. The changes of the prevalence of herpesviruses before the changes of clinical parameters could be detected after periodontal mechanical treatment. The patients should be re-evaluated and re-treated within 2 months after treatment.</p>

Analysis of alveolar bone loss and related factors in patients with aggressive periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the alveolar bone loss status and the related factors in aggressive periodontitis (AgP) patients.</p><p><b>METHODS</b>A total of 108 untreated AgP patients were included. The patients averaged 27.7 years of age with 45 males and 63 females. Twenty males were current smokers and the smoking status was evaluated by cigarette/day and packyears. The educational condition of the patients was recorded. The proximal probing depth (PD) of each tooth in all patients was measured and assessed (shallow: PD = 3, 4 mm, moderate: PD = 5, 6 mm, deep: PD ≥ 7 mm). The alveolar bone loss was assessed on a full set of periapical radiographs. The number of teeth with bone loss was scored in three categories (light bone loss, moderate bone loss and severe bone loss) for each patient. Based on the number of teeth (≥ 8 teeth) with severe alveolar bone loss and of the teeth lost, the patients (n = 108) were divided into severe AgP group (n = 61), and light-moderate group (n = 47).</p><p><b>RESULTS</b>There were significantly positive correlations between shallow pocket and light bone loss (r = 0.518, P = 0.000) or deep pocket and severe bone loss (r = 0.366, P = 0.000) in proximal sites. The number of teeth with light bone loss, moderate bone loss and severe bone loss was not significantly different between male (7.1 ± 6.2, 12.5 ± 4.7 and 5.1 ± 0.6) and female group (8.7 ± 6.3, 12.9 ± 4.8, 4.2 ± 0.5, P values were 0.707, 0.671 and 0.413 respectively). There were more teeth with moderate bone loss and severe bone loss in the elderly than in the young (13.6 ± 4.2 vs 11.0 ± 5.5, 5.2 ± 3.7 vs 3.6 ± 3.5, P < 0.01). The difference of teeth number with light bone loss, moderate bone loss and severe bone was not found between higher education and non-higher education groups (P values were 0.314, 0.862 and 0.407). Smoking status had a significant positive correlation with the number of the teeth with severe bone loss(r = 0.575, P = 0.032).</p><p><b>CONCLUSIONS</b>The bone loss status is related to the pocket depth. Smoking and age are risk factors for alvelar bone loss in AgP patients.</p>

Preliminary study of relationship between aggressive periodontitis and obesity / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between obesity and aggressive periodontitis (AgP).</p><p><b>METHODS</b>A total of 151 AgP patients and 94 healthy controls were recruited. Body weight and height were measured, and body mass index (BMI) was calculated. Periodontal clinical parameters were examined. Logistic regression analysis was used to evaluate the association between obesity and AgP.</p><p><b>RESULTS</b>The mean value of probing depth and clinical attachment loss were (4.8 +/- 2.1) mm and (4.7 +/- 2.8) mm respectively in AgP patients. The numbers of obese and underweight patients in AgP group were 20 and 41 respectively. Five and eight subjects in control group were with BMI values lower and higher than normal range respectively. Both under weight and obesity were risk indicators for AgP, and the OR were 3.60 (P < 0.05) and 4.61 (P < 0.01) respectively.</p><p><b>CONCLUSIONS</b>Underweight and obesity may be risk indicators for AgP.</p>

Evaluation of root abnormity in patients with aggressive periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To explore a method for classifying root abnormality and to investigate the status of root abnormality in patients with aggressive periodontitis (AgP).</p><p><b>METHODS</b>A total of 108 patients (2841 teeth) with AgP, 41 patients (1135 teeth) with chronic periodontitis (CP) and 30 periodontal healthy subjects (840 teeth) were included in the study. The abnormality of roots was evaluated on a full set of periapical radiographs. A reference parameter of "root width" in the middle of root was introduced in this study for classifying various types of root abnormality. The root abnormality was categorized into five types: cone-root (incisor, premolar), slender-root, curved-root, maladjusted proportion of crown and root, and synergetic root.</p><p><b>RESULTS</b>To compare with normal incisor root, the parameter of root width in cone-root incisor is much lower [up incisor: (0.04 +/- 0.01) and (0.10 +/- 0.03) cm; low incisor: (0.02 +/- 0.02) and (0.07 +/- 0.02) cm, P < 0.001], and root is shorter with maladjusted proportion of crown. To compare with normal root, the slender-root in low incisor and premolar cone-root, the parameters of root width are also lower [low incisors: (0.02 +/- 0.02) and (0.07 +/- 0.02) cm; up premolar: (0.03 +/- 0.03) and (0.07 +/- 0.01); low premolar: (0.02 +/- 0.01) cm and (0.18 +/- 0.26) cm, P < 0.001]. The number (or percentage) of teeth with root abnormality in AgP group, CP group, and control group was 407 (14.3%), 57 (5.0%), and 31 (3.7%), respectively. Significant differences of percentage of teeth with root abnormality were found among the three groups. AgP group had the highest percentages of teeth with root abnormality, while the control group had the lowest percentage.</p><p><b>CONCLUSIONS</b>The patients with aggressive periodontitis had more teeth with root abnormality than the patients with chronic periodontitis or healthy subjects. The root abnormality could be a local contributing factor for AgP patients.</p>

Prevalence of Actinobacillus actinomycetemcomitans in saliva of different types of periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of Actinobacillus actinomycetemcomitans (Aa) in whole saliva of different types of periodontitis and compare the detections of Aa between saliva and pooled subgingival plaque sample, and analyze the relationship between Aa and clinical conditions.</p><p><b>METHODS</b>Unstimulated whole saliva samples and pooled subgingival samples were collected from 50 aggressive periodontitis (AgP) patients, 48 chronic periodontitis (CP) patients and 25 subjects with no periodontitis, and Aa was detected in these samples by PCR method.</p><p><b>RESULTS</b>The prevalence of Aa in whole saliva of AgP patients was significantly higher than in subjects with no periodontitis (32% vs. 4%, P<0.01) and CP patients (32% vs. 15%, P<0.05). Aa was also more frequently detected in whole saliva sample than in pooled subgingival sample of AgP patients (32% vs. 16%, P<0.05). Subjects younger than 30 years old were more likely to present Aa in whole saliva ( OR = 3.23, P<0.05) and percentage of sites with bleeding index (BI) > or = 3 over 70% was a risk indicator for the presence of Aa in whole saliva</p><p><b>CONCLUSIONS</b>The detection of Aa in whole saliva sample of AgP patients was more frequent than in pooled subgingival plaque samples, and also more frequent than in CP patients and subjects with no periodontitis, which suggest that Aa may participate in the initiation and progression of aggressive periodontitis.</p>

Prevalence of putative periodontal microorganisms in Chinese patients with aggressive periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the prevalence of putative periodontal microorganism in Chinese patients with aggressive periodontitis (AgP).</p><p><b>METHODS</b>A total of 72 subgingival plaque samples were collected from 55 AgP patients and 17 healthy subjects. Seven putative periodontal microorganisms including Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Treponema denticola (Td), Campylobacter rectus (Cr), Prevotella intermedia (Pi) and Prevotella nigrescens (Pn) were detected by using 16S rRNA based polymerase chain reaction (PCR).</p><p><b>RESULTS</b>The prevalence of Aa in AgP patients was very low (1.8%), while Pg, Tf, Td and Cr were more frequently detected in AgP patients (prevalence: 81.8%, 83.6%, 80% and 81.8%) than in healthy controls (prevalence: 17.6%, 11.8%, 5.9%, 29.4%, P < 0.01).</p><p><b>CONCLUSIONS</b>The prevalence of Pg, Tf, Td and Cr were very high in aggressive periodontitis patients, and the combination of these bacteria may play an important role in AgP.</p>

Blood lipids and glucose levels in patients with periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine the serum levels of lipid and glucose in patients with periodontitis.</p><p><b>METHODS</b>The patients with aggressive periodontitis (AgP, n = 117) and chronic periodontitis (CP, n = 40) and healthy controls (n = 37) were recruited. Peripheral blood sample was obtained from each subject by venipuncture. Serum chemistry variables including total cholesterol, triglycerides, and fasting glucose were analyzed by biochemical analyzer.</p><p><b>RESULTS</b>The average serum levels of triglycerides and glucose of the patients with AgP [(1.09 +/- 0.79) mmol/L and (5.07 +/- 0.66) mmol/L] were both significantly higher than those of the control group [(0.94 +/- 0.28) mmol/L and (4.62 +/- 0.64) mmol/L], P < 0.05. Higher serum levels of total cholesterol and glucose were also observed in patients with CP [(4.61 +/- 1.23) mmol/L and (5.40 +/- 1.01) mmol/L] compared with controls [(4.49 +/- 0.78) mmol/L and (4.62 +/- 0.64) mmol/L], P < 0.05. Serum level of total cholesterol in AgP group was positively associated with percentage of severe sites (r = 0.25, P < 0.01).</p><p><b>CONCLUSIONS</b>Patients with periodontitis may have altered serum lipid and glucose levels compared with controls.</p>