Changes of Microbial Community in Treated Peri-implantitis Sites: An Experimental Study in Beagle Dogs.

OBJECTIVE: To investigate the changes of the bacterial community in the oral environment of beagle dogs to gain insights on the possible causes of failed therapy in peri-implantitis. METHODS: Beagles were used as models for experimental peri-implantitis. Samples from peri-implant soft tissue (supramargin and submargin), ligature and contaminated surface of peri-implantitis sites were collected and analysed by sequencing the bacterial 16S rRNA gene. RESULTS: The residual microbial community from the curettes-treated implant surface contained a variety of microorganisms, including periodontal pathogens, which showed no changes in their composition and structure. CONCLUSION: It is possible that the residual bacterial community remained unchanged and this was the cause of recurrent episodes of inflammation.

Accuracy Assessment of Three-dimensional Surface Reconstructions of In vivo Teeth from Cone-beam Computed Tomography.

BACKGROUND: The accuracy of three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) has been particularly important in dentistry, which will affect the effectiveness of diagnosis, treatment plan, and outcome in clinical practice. The aims of this study were to assess the linear, volumetric, and geometric accuracy of 3D reconstructions from CBCT and to investigate the influence of voxel size and CBCT system on the reconstructions results. METHODS: Fifty teeth from 18 orthodontic patients were assigned to three groups as NewTom VG 0.15 mm group (NewTom VG; voxel size: 0.15 mm; n = 17), NewTom VG 0.30 mm group (NewTom VG; voxel size: 0.30 mm; n = 16), and VATECH DCTPRO 0.30 mm group (VATECH DCTPRO; voxel size: 0.30 mm; n = 17). The 3D reconstruction models of the teeth were segmented from CBCT data manually using Mimics 18.0 (Materialise Dental, Leuven, Belgium), and the extracted teeth were scanned by 3Shape optical scanner (3Shape A/S, Denmark). Linear and volumetric deviations were separately assessed by comparing the length and volume of the 3D reconstruction model with physical measurement by paired t- test. Geometric deviations were assessed by the root mean square value of the imposed 3D reconstruction and optical models by one-sample t-test. To assess the influence of voxel size and CBCT system on 3D reconstruction, analysis of variance (ANOVA) was used (µ = 0.05). RESULTS: The linear, volumetric, and geometric deviations were -0.03 ± 0.48 mm, -5.4 ± 2.8%, and 0.117 ± 0.018 mm for NewTom VG 0.15 mm group; -0.45 ± 0.42 mm, -4.5 ± 3.4%, and 0.116 ± 0.014 mm for NewTom VG 0.30 mm group; and -0.93 ± 0.40 mm, -4.8 ± 5.1%, and 0.194 ± 0.117 mm for VATECH DCTPRO 0.30 mm group, respectively. There were statistically significant differences between groups in terms of linear measurement (P < 0.001), but no significant difference in terms of volumetric measurement (P = 0.774). No statistically significant difference were found on geometric measurement between NewTom VG 0.15 mm and NewTom VG 0.30 mm groups (P = 0.999) while a significant difference was found between VATECH DCTPRO 0.30 mm and NewTom VG 0.30 mm groups (P = 0.006). CONCLUSIONS: The 3D reconstruction from CBCT data can achieve a high linear, volumetric, and geometric accuracy. Increasing voxel resolution from 0.30 to 0.15 mm does not result in increased accuracy of 3D tooth reconstruction while different systems can affect the accuracy.

The effect of local delivery of adiponectin from biodegradable microsphere-scaffold composites on new bone formation in adiponectin knockout mice.

Adiponectin (APN) is the most abundant adipocyte-secreted adipokine; it regulates energy homeostasis and exerts well-characterized insulin-sensitizing properties. Previous studies have verified that globular adiponectin (gAPN) is also involved in bone metabolism, although observations have been controversial. The purpose of the current study is to use an APN-knockout (APN-KO) mouse model to evaluate the local delivery of gAPN to new bone formation. Using chitosan microspheres (CMs), we found that following an initial burst at 1 week, the release behavior of gAPN from the scaffold was sustained in a linear manner for the first 4 weeks, followed by a slower, more stable release from week 5 onwards. Interestingly, PLGA/ß-TCP/CM-loaded gAPN scaffolds implanted in APN-KO mice increased bone formation and mineralization, and enhanced osteogenic marker expression 28 days post-implantation. gAPN also promoted preosteoblast (MC3T3-E1) cellular proliferation in vitro. In MC3T3-E1 cells, adaptor protein-containing pleckstrin homology domain, phosphotyrosine domain, leucine zipper motif (APPL1) and phosphoinositide 3-kinase (PI3K) expression was upregulated in a time-dependent manner upon gAPN treatment, while APPL1 small interfering RNA (siRNA) pre-treatment reversed this enhanced expression. In conclusion, modified bone graft substitutes loaded with gAPN increase bone formation and mineralization in part by promoting osteoblast proliferation via the APPL1/PI3K pathway.

[Validation of the American College of Rheumatology classification criteria for primary Sjogren's syndrome in Chinese patients].

OBJECTIVE: To validate the American College of Rheumatology Classification (ACR) Criteria (2012) for the diagnosis of primary Sjogren's syndrome in Chinese patients. METHODS: All patients involved in this study came from the Department of Oral Medicine Peking University Stomatology Hospital. They were devided into two groups of pSS and non-pSS according to the diagnoses made by two experts. Both groups of the patients had completed medical records kept in the hospital. RESULTS: A total of 239 pSS patients (160 with labial salivary gland biopsy, and 79 without biopsy) and 52 age-matched non-pSS patients [(55.17±14.295),and (55.90±13.38) years old, P>0.05] (9 with biopsy, and 43 without biopsy) were involved in this study. The sensitivity and specificity of ACR criteria in diagnosing pSS were 90.37 % and 88.46 % respectively. The positive and negative likelihood ratios were 7.83 and 0.109, respectively. The sensitivities of ACR criteria in diagnosing pSS patients with and without labial biopsy were 88.75% and 93.67 %, respectively, with specificities of 88.89% and 88.37%, respectively. The most sensitive item adopted in ACR criteria was the ocular staining score with a sensitivity of 85.77%, and the most specific item was the labial salivary gland biopsy, with a specificity of 88.89%. CONCLUSION: The sensitivity and specificity of ACR criteria in diagnosing Chinese pSS patients were relatively high, and may serve as the diagnosis criteria in research and clinical practice. However, the ACR criteria need to be validated and further revised in the future .

[Preliminary study of the relationship between tumor like Sjögren's syndrome and malignant lymphoma].

OBJECTIVE: To investigate the clinical and laboratory characteristics of tumor like Sjögren's syndrome (TLSS) patients and non-tumor like Sjögren's syndrome (NTLSS) and the incidence of lymphoma in patients of Sjögren's syndrome (SS). METHODS: A retrospective analysis was carried out in 199 primary SS (including TLSS) patients who were recruited in Peking University School and Hospital of Stomatology from 1998 to 2010. Clinical and laboratory information were collected. The patients were divided into two groups: TLSS (n = 25) and NTLSS (n = 174). Clinical and laboratory characteristics were compared between these two groups by a statistical analysis. RESULTS: Of the 25 TLSS patients, 23 had enlargements of parotid glands and 2 had enlargements of submandibular glands. There were significant differences of salivary scintigraphy appearance (P = 0.018), hypergammaglobulinemia (P = 0.014), rheumatoid factor positive rate (P = 0.001), formation of the ectopic germinal centers (P = 0.014), double positive rate of anti-SSA antibody and anti-SSB antibody (P < 0.001) between the TLSS and NTLSS patients. Among the 25 TLSS patients, 3 developed lymphomas, accounting for 1.5% (3/199) of the total 199 patients and 12% (3/25) of the TLSS patients. Lymphoma subtypes included one diffused large B-cell lymphoma and two mucosa-associated lymphoid tissue lymphoma. There was no lymphoma detected in NTLSS patients. CONCLUSIONS: There are clinical and laboratory differences between TLSS and NTLSS patients, with a more tendency to develop lymphomas in TLSS patients.