Accuracy of three-dimensional periodontal ligament models generated using cone-beam computed tomography at different resolutions for the assessment of periodontal bone loss / 대한치과교정학회지

Objective@#To develop a method for generating three-dimensional (3D) digital models of the periodontal ligament (PDL) using 3D cone-beam computed tomography (CBCT) reconstruction and to evaluate the accuracy and agreement of the 3D PDL models in the measurement of periodontal bone loss. @*Methods@#CBCT data collected from four patients with skeletal Class III malocclusion prior to periodontal surgery were reconstructed at three voxel sizes (0.2 mm, 0.25 mm, and 0.3 mm), and 3D tooth and alveolar bone models were generated to obtain digital PDL models for the maxillary and mandibular anterior teeth. Linear measurements of the alveolar bone crest obtained during periodontal surgery were compared with the digital measurements for assessment of the accuracy of the digital models. The agreement and reliability of the digital PDL models were analyzed using intra- and interexaminer correlation coefficients and Bland–Altman plots. @*Results@#Digital models of the maxillary and mandibular anterior teeth, PDL, and alveolar bone of the four patients were successfully established. Relative to the intraoperative measurements, linear measurements obtained from the 3D digital models were accurate, and there were no significant differences among different voxel sizes at different sites. High diagnostic coincidence rates were found for the maxillary anterior teeth. The digital models showed high intra- and interexaminer agreement. @*Conclusions@#Digital PDL models generated by 3D CBCT reconstruction can provide accurate and useful information regarding the alveolar crest morphology and facilitate reproducible measurements. This could assist clinicians in the evaluation of periodontal prognosis and establishment of an appropriate orthodontic treatment plan.

Digital evaluation of supracrestal gingival thickness induced by periodontal regenerative and corticotomy surgery in patients with skeletal class Ⅲ malocclusion / 中华口腔医学杂志

Objective@#To establish a quantitative three-dimensional method based on intraoral scan to evaluate the changes of soft tissue, and to evaluate the changes of supracrestal gingival thickness (SGT) in skeletal class Ⅲ patients induced by periodontal regenerative and corticotomy surgery (PRCS).@*Methods@#Twenty-two systematically and periodontally healthy skeletal class Ⅲ patients (4 males and 18 females, aged between 19 and 35 years), who were in need of combined orthodontic-orthognathic treatment and referred to the Department of Periodontology from the Department of Orthodontics and the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from January, 2018 to March, 2019, were collected in the study. The teeth involved were 112 anterior teeth (46 maxillary anterior teeth and 66 mandibular anterior teeth). PRCS in anterior tooth area was conducted before orthodontic decompensation. Probing depth (PD), bleeding index (BI) and keratinized gingiva width (KGW) were recorded before surgery and 6 months post-surgery. The intraoral digital impressions of maxillary and mandibular anterior teeth were obtained by 3-shape intraoral scanner before surgery and 6 months after surgery. The Standard Tessellation Language (STL) files were processed using Geomagic qualify 12.2 software to establish the soft tissue morphological measurement model, and to quantitatively analyze the changes of gingival thickness situated 1 to 2 mm apical to the free gingival margin on the median sagittal measurement plane.@*Results@#Probing depth and bleeding index had no significant difference before and 6 months after operation (P>0.05). KGW in 6-month post-operation group [(5.18±2.32) mm] was significantly higher than that in pre-operation group [(4.22±1.43) mm] (P<0.05). Supracrestal gingival thickness situated 1 to 2 mm apical to the free gingival margin also significantly increased 6 months after surgery (P<0.05). The changes of gingival thickness situated 1 to 2 mm apical to the free gingival margin in the upper anterior area were (0.68±0.56) and (1.00±0.69) mm, respectively. The changes in the lower anterior area were (0.38±0.42) and (0.58±0.45) mm, respectively. The gingival changes of the upper anterior teeth were also significantly higher than those of the lower anterior teeth (P<0.01).@*Conclusions@#The described quantitative measurement based on intraoral scan could be an effective method for quantitative evaluation of the changes of soft tissue. PRCS could safely increase the supracrestal gingival thickness as well as KGW in skeletal class Ⅲ patients who were in need of combined orthodontic-orthognathic treatment.

Short-term clinical efficacy of a collagen matrix and free gingival graft in augmenting keratinized mucosa around dental implants / 中华口腔医学杂志

Objective@#To compare the short-term outcomes of a collagen matrix (CM) and free gingival graft (FGG) in augmenting keratinized mucosa around dental implants.@*Methods@#Nineteen partially edentulous patients who had undergone implant surgery or implant review from June 2017 to June 2018 at Department of Periodontology, Peking University School and Hospital of Stomatology with lack of keratinized mucosa at buccal aspect of implants (<2 mm) were recruited in this study. According to the width of keratinized mucosa (KW) pre-operation, 9 patients including 5 males and 4 females were assigned into control group (KW<0.5 mm) which performed free gingival graft (17 implants) and 10 patients including 3 males and 7 females were assigned into experimental group (KW≥0.5 mm) which used collagen matrix as the grafts (15 implants). The KW at buccal aspect of each implant were measured pre-operation and 2 weeks, 1 month, 2 months, 3 months after surgery respectively. Each of the patients was required to fill out a questionnaire using a visual analogue scale to assess the postoperative morbidity.@*Results@#The KWs around implants were increased significantly during the 3 months follow-up period in both groups (P<0.01). At 3 months after surgery, KW gain in control group was (3.44±1.64) mm, in experimental group was (2.30±0.82) mm, the difference between two groups was statistically significant (P<0.05). Meantime, the total shrinkage of KW in control group [(34±25)%] and experimental group [(51±11)%] also showed a statistically significant difference (P<0.01). However, by using collagen matrix as the grafts, augmented tissues had a much more comparable appearance with adjacent tissues than that in control group. And the patients of experimental group experienced much less postoperative bleeding than those of control group.@*Conclusions@#Both collagen matrix and free gingival graft can significantly increase the KW around implants within the 3 months post-surgery follow-up period. There were more KW gain and less shrinkage in group FGG than that in group CM. However, surgery time were reduced and the postoperative bleeding were less in group CM than in group FGG as no harvesting procedure was needed.

Influences on periodontal health and conditions of patients with periodontitis by clear aligner treatment / 中华口腔医学杂志

No matter what kind of therapies you choose, clear aligner treatment (CAT) or fixed orthodontic treatment (FOT), the therapy must be performed on the basis of periodontal health and follow the rule that the treatment cannot be harmful to the periodontal tissues. Doctors and patients prefer the clear aligner treatment because of its features, such as aesthetic, removable and comfortable. There are many studies which consider the influences of CAT on the periodontal health, and the conclusions are relatively consistent. The CAT is more beneficial for the plaque-control and maintaining the periodontal health. However, there are a few articles which are talking about applying the CAT to the patients with severe periodontitis. This article mainly reviews the effect of CAT towards the patients with periodontitis, and provides some reference when the patients with severe periodontitis need to choose a proper treatment.

A decision tree for treatment of patients with gingival Stillman's cleft / 中华口腔医学杂志

Gingival Stillman's cleft is a mucogingival triangular- shaped defect which influence on health and appearance of gingiva. Due to a lack of clinical reports, five cases of gingival Stillman's cleft were recruited in the present study. The treatment methods were selected according to the etiological factors of the defect in each patient. Satisfactory treatment responses were achieved in all cases during a 6 to 20 month follow up after the treatments. In this study, we summarized the treatment strategies in various types of gingival Stillman's cleft, so as to provide the reference for clinicians.

The effect of individualized oral hygiene Instruction on volatile sulfur compounds level in mouth air / 中华护理杂志

Objective To determine the effect of individualized oral hygiene instruction (OHI) on volatile sulfur compounds (VSCs) level in mouth air of patients with chronic periodontitis.Methods The individualized oral hygiene instruction was provided for 31 patients with chronic periedontitis (Organoleptic score was over two points).The VSCs and plaque index (PLI) were evaluated pre-OHI and post-OHI.Results The score of PLI decreased from 3.09±0.44 to 2.63±0.46 significandy (P<0.05).The organoleptic score (OS) decreased from 2.68±0.70 to 2.35±0.75 significandy (P<0.05).While there was no significant difference on the VSCs level pre-OHI and post-OHI (P<0.05).Conclusions Individualized oral hygiene instruction is helpful to remove plaque and improve oral hygiene.But the effect of OHI on VSCs level in mouth air is limited.

Uitrastructure of three types of periodontal cells / 中国医师杂志

Objective To study the ultrastrueture of 3 types of periodontal cells, including periodontal ligament cells (PDLC), os-teoblast cells (OB) and eementoblast cells (CB). Methods After culturing 3 kinds of periodontal cells - PDLC, OB and CB, we observed them with transmission electron microscope. Results There was rich rough endoplasmic reticulum and lots of microfilaments in the cyto-plasm of CB and PDLC cells. There was rich rough endoplasmic in the cytoplasm of OB cells. Conclusion The main characteristic ultra-structure feature of the bovine CB and PDLC was rich rough endoplasmic reticulum and microfilaments in the cytoplasm. Compared with CB and PDLC, OB contained fewer microfilaments in the cytoplasm.

Isolation, culture and identification of bovine cementum-derived cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To isolate and culture bovine cementum-derived cells and investigate their biological properties.</p><p><b>METHODS</b>Culture of primary bovine cementoblast (CB) were established from new-born bovine teeth. Cementum was manually dissected, fragmented, and digested twice with collagenase. Following a thorough wash to remove liberated cells, the remaining cementum fragments were plated and cultured in RPMI1640 containing 10% FCS and 1.5% Hepes. The cells in culture were identified using immunocytochemistry by expression of cementum attachment protein (CAP), osteocalcin (OCN) and alkaline phosphatase (ALP). ALP activity was measured by modified Gomori staining.</p><p><b>RESULTS</b>(1) The cells in culture possessed the typical morphology of CB and there were no obvious change of the cell morphology up to 5th passage; (2) Cells in culture exhibited alkaline phosphatase activity and were also positive to CAP, OPN and ALP immunohistochemistry staining.</p><p><b>CONCLUSION</b>The cells isolated and cultured in this experiment possess the properties of CB. This enables us to further observe its biological characteristics during cementogenesis and periodontal regeneration.</p>

Sequential Expression of Mineralization Related Proteins in Cementoblast During Mineralized Culture in Vitro / 中国医师杂志

Objective To investigate sequential expression of bone sialoprotein(BSP), alkaline phosphatase(ALP) and cementum attachment protein(CAP) in cementoblast(CB) during mineralized culture in vitro, and study the morphological and biologic characters of the CB in this process. Methods CB was seeded on the glass coverslips, and cultured for 6h, 12h, 1d, 2d, 3d, 4d, 5d, 6d, 8d, 10d, 12d and 16d, respectively. The expression of BSP, ALP and CAP proteins was detected using immunocytochemical method. Results 6 hours after plated, cementoblast expressed all of the three proteins. In the second and third days after plated, the cells became confluent and formed multiple layers, BSP and ALP expression decreased, and CAP did not be expressed at all. From the forth day, the cells formed cell nodules with mineralizing function. The cells in the nodules strongly expressed BSP,ALP and CAP, the cells around the nodule weakly expressed BSP and ALP, and did not express ALP. During the following 10 to 16 days, the cell nodules became mineralized nodules. Conclusion These results elucidated the changes of ALP, BSP and CAP expression as well as cell morphology during the CB proliferation, differentiation and mineralization in vitro, and provided some valuable information for studying the formation of cementum and CB proliferation, differentiation and mineralization in vivo.

The effects of human salivary statherin on adherence of cariogenic bacteria to hydroxyapatite in vitro / 实用口腔医学杂志

砄bjective:To investigate the effects of salivary statherin on adherence of two kinds of main cariogenic bacteria. Methods: Human whole salivary statherin was separated and purified by high performance hydrophobic interaction chromatography (HPHIC) and was further identified by SDS PAGE electrophoresis and amino acid analysis.Then the adherence of Streptococcus mutans ( S.mutans serotype c,7H) and Sreptococcus sanguis (S.sanguis ,ATCC 10557)to hydroxyapatite (HA), which was covered with purified statherin or whole saliva (positive control) or PBS buffer (negative control) as experimental pellicles respectively,was studied by bacteria counting.Results:①More S.sanguis adhered to the experimental pellicles than S.mutans ( P