Unusual clinical presentation of oral pyogenic granuloma with severe alveolar bone loss:A case report and review of literature

BACKGROUND Pyogenic granuloma(PG)is a localized,reddish and vascularized hyperplastic lesion of the connective tissue which occurs in the oral cavity.In most cases,the presence of this lesion does not show alveolar bone resorption.The pathology is diagnosed clinically with some caution.However,the diagnosis and treatment are usually corroborated with histopathological evidence.CASE SUMMARY Three clinical cases of PG associated with bone loss were described in this study.The three patients presented tumor-like growth which bled on touch,and were associated with local irritant factors.Radiographs showed bone loss.All cases were treated with conservative surgical excision.The scarring was satisfactory,and there was no case of recurrence.The diagnoses were based on clinical findings,and were confirmed histopathologically.CONCLUSION The occurrence of oral PG with bone loss is unusual.Therefore,clinical and radiographic evaluations are important for the diagnosis.

The Association between Lower Incisal Inclination and Morphology of the Supporting Alveolar Bone—A Cone-Beam CT Study

Aim To investigate the relationship between the positioning of the lower central incisor and physical morphology of the surrounding alveolar bone. Methodology Thirty-eight patients （18 males, 20 females）, with mean age of 13.4 years, were included in this study. As part of orthodontic treatment planning the patients were required to take dental Cone-beam CT （CBCT） covering the region of lower incisors, the sur- rounding alveolar bone and the mandibular symphysis. The cephalometric parameters were designed and measured to indicate the inclination of lower central incisor and physical morphology of the adjacent alveolar bone. Computer-aided descriptive statistical analysis was performed using SPSS 15.0 software package for Windows. A correlation analysis and a linear regression analysis between the incisor inclination and the alveolar bone morphology were performed. Results Significant positive correlations were found between the lower central incisor inclination and the morphological contour of the alveolar bone （P〈0.05）. The lower central incisor root apex was closer to the lingual alveolar crest when it was buccally inclined. Conclusion The morphology of the alveolar bone may be affected by incisal inclination.

Cone beam computed tomographic analyses of alveolar bone anatomy at the maxillary anterior region in Chinese adults

To provide an anatomical basis for clinical implant esthetics,we evaluated the morphology of the nasopalatine canal（NPC） and analyzed labial and interproximal bone anatomy at the maxillary anterior region.We sought to investigate the effect of maxillary protrusion and tooth labiolingual inclination on labial bone anatomy in Chinese adults.Three dimensional（3D） images were reconstructed using cone-beam computed tomography（CBCT） images from 80 Chinese subjects and by SimPlant 11.04.The dimensions of the NPC,the thickness and profile of the labial bone,the width and height of the interproximal bone,angle sella-nasion-subspinale（SNA） and angle upper central incisor-nasion,subspinale（U1-NA） were measured.The incisive foramen of the NPC was markedly wider than its nasal foramen.The dimension of its labial bone wall demonstrated an increasing width from the crestal to apical measurements.The labial bone at the maxillary anterior region was rather thin,especially at 3 mm below the cemento-enamel junction（CEJ） and the mid-root level;the profile of the labial bone was more curved at the central incisor,and the interproximal bone became wider and shorter posteriorly.There were significant relationships between maxillary protrusion and labial bone profile,tooth labiolingual inclination and labial bone thickness（P 〈 0.02）.To achieve optimal esthetic outcome of implant,bone augmentation is necessary at the maxillary anterior region.For immediate or early placement at the maxillary anterior region,the implant should be located palatally to reduce labial bone resorption and marginal recession;its apex should be angulated palatally to avoid labial perforation at the apical region.To protect the NPC,implants at the central incisor region should be placed away from NPC.

Effects of Er-Zhi-Wan on Microarchitecture and Regulation of Wnt/β-catenin Signaling Pathway in Alveolar Bone of Ovariectomized Rats

Recent studies have shown that Er-Zhi-Wan（EZW）, a traditional Chinese medicine consisting of Herba Ecliptae（HE） and Fructus Ligustri Lucidi（FLL）, had a definite antiosteoporotic effect on osteoporotic femur, but its effect on osteoporosis of alveolar bone remains unknown. In the present study, we investigated the effects of Er-Zhi-Wan（EZW） on the microarchitecture and the regulation of Wnt/β-catenin signaling pathway in the alveolar bone of ovariectomized rats. Thirty Sprague-Dawley rats were randomly divided into three groups： sham operation group（sham, n=10）, ovariectomy（OVX） group（n=10）, and OVX with EZW treatment group（EZW group, n=10）. From one week after ovariectomy, EZW（100 mg/mL） or vehicle（distilled water） was fed（1 mL/100 g） once per day for 12 weeks until the sacrifice of the rats. The body weights were measured weekly. After sacrifice, the sera and mandible were collected and routinely prepared for the measurement of alveolar trabecular microarchitecture, serum levels of E2, bone-specific alkaline phosphatase（BALP） and tartrate-resistant acid phosphatase 5b（TRAP5b）, as well as mandibular mRNA expression of Wnt/β-catenin signaling pathway molecules wnt3a, low-density lipoprotein receptor-related protein 5（LRP5）, β-catenin and dickkopf homolog 1（DKK1）. The results showed that EZW treatment significantly prevented the body weight gain, degradation of alveolar trabecular microarchitecture and alveolar bone loss in the OVX rats. Furthermore, we observed that EZW could increase the serum levels of E2 and BALP, and decrease levels of serum TRAP5b in EZW group compared with vehicle group. In addition, RT-PCR results revealed that EZW upregulated the expression levels of wnt3a, LRP5 and β-catenin, and reduced the expression of DKK1 in OVX rats. Taken together, our results suggested that EZW may have potential anti-osteoporotic effects on osteoporotic alveolar bone by stimulating Wnt/LRP5/β-catenin signaling pathway.

Micromolar sodium fluoride mediates anti-osteoclastogenesis in Porphyromonas gingivalis-induced alveolar bone loss

Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone-lytic diseases. Periodontitis is an inflammatory disease characterized by extensive bone resorption. In this study, we investigated the effects of sodium fluoride （NaF） on osteoclastogenesis induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of cathepsin K, interleukin （IL）-1β, matrix metalloproteinase 9 （MMP9）, and tartrate-resistant acid phosphatase, which were up-regulated during P. gingivalis-induced osteoclastogenesis. Consistent with the in vivo anti-osteoclastogenic effect, NaF inhibited osteoclast formation caused by the differentiation factor RANKL （receptor activator of nuclear factor KB ligand） and macrophage colony-stimulating factor （M-CSF）. The RANKL-stimulated induction of the transcription factor nuclear factor of activated T cells （NFAT） cl was also abrogated by NaF. Taken together, our data demonstrate that NaF inhibits RANKL-induced osteoclastogenesis by reducing the induction of NFATcl, ultimately leading to the suppressed expression of cathepsin K and MMP9. The in vivo effect of NaF on the inhibition of P. gingivalis-induced osteoclastogenesis strengthens the potential usefulness of NaF for treating periodontal diseases.

Influence of Masticatory Functional Loss on the Remodeling of Alveolar Bone in Rats

There is plenty of literature on masticatory function and its impact on maxillofacial development. However, the influence of masticatory hypofunction on bone turnover in the alveolar bone has hardly been studied. This study aimed to clarify the influence of tooth loss and soft diet on the alveolar bone turnover during the growth period. Three-week-old Wistar rats were randomly divided into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). BV, BMC, and BMD in the cancellous bone of M1 were measured using micro-CT analysis. To analyze the histological bone turnover, we prepared non-decalcified thin sections of alveolar cancellous bone when rats were 20 weeks old. On three-dimensional constructed images, the experimental groups (the Powder diet and Extraction groups) showed expansion of the medullary cavity of the interradicular septum of the first molar compared to controls (the Hard diet group). BV, BMC, and BMD were significantly lower in the experimental groups, with the difference from controls being greater in the Extraction group. On histomorphometric analysis, the bone mass parameters, bone formation parameters, and bone mineralization parameters were significantly lower in the experimental groups compared to controls. The bone resorption parameters were significantly higher in the experimental groups. From this study, we found that soft diet and tooth loss might worsen the bone microstructure, reduce osteogenesis, and promote bone resorption in alveolar bone.

A RETROSPECTIVE STUDY OF BILATERAL ALVEOLAR BONE GRAFTING

To evaluate the treatment results of bilateral alveolar bone grafting (BABG) in patients with bilateral complete clefts of lip and palate. [WT5”BX] Methods.[WT5”BZ] A retrospective study was performed in 66 bilateral complete cleft lip and palate patients who received the procedure of BABG, among them 15 were primary BABG and 51 were secondary BABG. The patients were further divided into three groups according to age and eruption stage of the canine at the time of surgery. The result of BABG was evaluated on the radiographs. [WT5”BX] Results.[WT5”BZ] (1)The overall success rate of BABG was 75 0%, with 83 3% and 72 5% for primary and secondary BABG respectively; (2)The marginal bone level was found to be significantly higher in the youngest age group than in the other groups both for primary and secondary BABG; (3)For both primary and secondary BABG, Group C (patients’ age more than 16 years) had the least optimal success rate, with 66 7% and 65 4% respectively. [WT5”BX] Conclusion.[WT5”BZ] Simultaneous primary palate repair and BABG is safe and feasible procedure for treating unoperated bilateral complete cleft lip and cleft palate patients. For both primary and secondary BABG, significantly better results can be achieved if the operation is performed before eruption of the canine.

Crohn's Disease and Primary Alveolar Bone Loss A literature Review and Case Report

克罗恩病是一种病因尚不明确的慢性肠道炎性肉芽肿性疾病。偶有口腔组织受累,损害主要见于唇、颊黏膜及牙龈。本文报道一例有口腔病变的克罗恩病,24岁,男性,口腔溃疡不愈半年,伴有2月腹痛史。口腔溃疡活检病理诊断为克罗恩病。临床检查发现除了消化道病损、口腔溃疡、上颌窦黏膜增厚外,出现了罕见的广泛牙槽骨吸收,而患者无牙周病及激素用药史,这一特点在以前的文献中未见报道。

Comparing the methods of oral hygiene, over hanged removal and restoration—Changing on periodontal health and alveolar bone height of rest orated mandibular molars with proximal over hanged amalgam

Objective: Conservative restoration principles that accurately reduce plaque accumulation are the goals of restorative dentistry. Correct and perfect restoration has an important effect on health of periodontious tissues. This study was done to compare the methods of oral hygiene, over hanged removal and restoration changing on periodontal health and alveolar bone height of restored mandible molars with proximal over hanged amalgam. Materials and Methods: All patients with over hanged amalgam restoration were randomly divided into three groups. In order to survey the effect of over hanged removal on gingival and bleeding indices and alveolar bone height adjacent to mandible molar teeth, these indices were determined according to recurrent radio-graphical early signs of alveolar bone loss during three months. Sixty patients, 20 in each group, were studied. In the group I, overhang was removed with ultrasonic scale or bur and oral hygiene methods as usual were continued. In the group II, over-hang was left, but plaque controls as the prophylaxis and flossing were done. In the group III, restoration was changed and oral hygiene was done as usual. Plaque index and bleeding index were measured at the beginning of study and three months later. Findings: Statistical analysis of studied indices at the beginning and three months after treatment using paired test has shown significant differences in gingival inflammation, in all groups. Statistical analysis of indices using Tukey HSD test has also shown significant differences in decreasing gingival inflammation measure when the over hanged restoration was removed. While there is no difference between the other two groups. Conclusion: The results showed that plaque control causes subsidence of gingival inflammation and increasing of alveolar bone support, and it is more effective when the over hanged restoration is changed.

A five-in-one novel MOF-modified injectable hydrogel with thermo-sensitive and adhesive properties for promoting alveolar bone repair in periodontitis:Antibacterial,hemostasis,immune reprogramming,pro-osteo-/angiogenesis and recruitment

Periodontitis is a chronic inflammatory disease caused by plaque that destroys the alveolar bone tissues,resulting in tooth loss.Poor eradication of pathogenic microorganisms,persistent malignant inflammation and impaired osteo-/angiogenesis are currently the primary challenges to control disease progression and rebuild damaged alveolar bone.However,existing treatments for periodontitis fail to comprehensively address these issues.Herein,an injectable composite hydrogel(SFD/CS/ZIF-8@QCT)encapsulating quercetin-modified zeolitic imidazolate framework-8(ZIF-8@QCT)is developed.This hydrogel possesses thermo-sensitive and adhesive properties,which can provide excellent flowability and post-injection stability,resist oral fluid washout as well as achieve effective tissue adhesion.Inspirationally,it is observed that SFD/CS/ZIF-8@QCT exhibits a rapid localized hemostatic effect following implantation,and then by virtue of the sustained release of zinc ions and quercetin exerts excellent collective functions including antibacterial,immunomodulation,pro-osteo-/angiogenesis and pro-recruitment,ultimately facilitating excellent alveolar bone regeneration.Notably,our study also demonstrates that the inhibition of osteo-/angiogenesis of PDLSCs under the periodontitis is due to the strong inhibition of energy metabolism as well as the powerful activation of oxidative stress and autophagy,whereas the synergistic effects of quercetin and zinc ions released by SFD/CS/ZIF-8@QCT are effective in reversing these biological processes.Overall,our study presents innovative insights into the advancement of biomaterials to regenerate alveolar bone in periodontitis.

Bioactive materials from berberine-treated human bone marrow mesenchymal stem cells promote alveolar bone regeneration by regulating macrophage polarization

Alveolar bone regeneration has been strongly linked to macrophage polarization.M1 macrophages aggravate alveolar bone loss,whereas M2 macrophages reverse this process.Berberine(BBR),a natural alkaloid isolated and refined from Chinese medicinal plants,has shown therapeutic effects in treating metabolic disorders.In this study,we first discovered that culture supernatant(CS)collected from BBR-treated human bone marrow mesenchymal stem cells(HBMSCs)ameliorated periodontal alveolar bone loss.CS from the BBR-treated HBMSCs contained bioactive materials that suppressed the M1 polarization and induced the M2 polarization of macrophages in vivo and in vitro.To clarify the underlying mechanism,the bioactive materials were applied to different animal models.We discovered macrophage colony-stimulating factor(M-CSF),which regulates macrophage polarization and promotes bone formation,a key macromolecule in the CS.Injection of pure M-CSF attenuated experimental periodontal alveolar bone loss in rats.Colony-stimulating factor 1 receptor(CSF1R)inhibitor or anti-human M-CSF(M-CSF neutralizing antibody,Nab)abolished the therapeutic effects of the CS of BBR-treated HBMSCs.Moreover,AKT phosphorylation in macrophages was activated by the CS,and the AKT activator reversed the negative effect of the CSF1R inhibitor or Nab.These results suggest that the CS of BBR-treated HBMSCs modulates macrophage polarization via the M-CSF/AKT axis.Further studies also showed that CS of BBR-treated HBMSCs accelerated bone formation and M2 polarization in rat teeth extraction sockets.Overall,our findings established an essential role of BBR-treated HBMSCs CS and this might be the first report to show that the products of BBR-treated HBMSCs have active effects on alveolar bone regeneration.

An injectable and coagulation-independent Tetra-PEG hydrogel bioadhesive for post-extraction hemostasis and alveolar bone regeneration

Effective control of post-extraction hemorrhage and alveolar bone resorption is critical for successful extraction socket treatment,which remains an unmet clinical challenge.Herein,an injectable Tetra-PEG hydrogel that possesses rapid gelation,firm tissue adhesion,high mechanical strength,suitable degradability,and excellent biocompatibility is developed as a sutureless and coagulation-independent bioadhesive for the management of extraction sockets.Our results demonstrate that the rapid and robust adhesive sealing of the extraction socket by the Tetra-PEG hydrogel can provide reliable protection for the underlying wound and stabilize blood clots to facilitate tissue healing.In vivo experiments using an anticoagulated rat tooth extraction model show that the hydrogel significantly outperformed clinically used cotton and gelatin sponge in hemostatic efficacy,wound closure,alveolar ridge preservation,and in situ alveolar bone regeneration.Histomorphological evaluations reveal the mechanisms for accelerated bone repair through suppressed long-term inflammation,elevated collagen deposition,higher osteoblast activity,and enhanced angiogenesis.Together,our study highlights the clinical potential of the developed injectable Tetra-PEG hydrogel for treating anticoagulant-related post-extraction hemorrhage and improving socket healing.

Dual stimulus responsive borosilicate glass(BSG)scaffolds promote diabetic alveolar bone defectsrepair by modulating macrophage phenotype

The regeneration of alveolar bone is still clinical challenge,particularly accompanied with diabetes,causing metabolic disorder with a protracted low-grade inflammatory phenotype.As a result,the anticipated loading of biomaterials is highly suspicious in spontaneous modulation of cells function,which is mostly disturbed by constant inflammation.In this study,we developed glucose and hydrogen peroxide dual-responsive borosilicate glass(BSG)scaffolds loaded with epigallocatechin gallate(EGCG)to synergistically modulate the abnormal inflammation of diabetic alveolar bone defects.It was found that the release of EGCG by BSG could directly regulate the shift of macrophages from M1 to the M2 phenotype by promoting autophagy and lessening the inhibition of autophagic flux.Moreover,EGCG can also indirectly regulate the polarization phenotype of macrophages by reducing the activation of NF-κb in stem cells and restoring its immunoregulatory capacity.Therefore,the addition of EGCG to BSG scaffold in diabetes allows for a more striking modulation of the macrophage phenotype in a timely manner.The altered macrophage phenotype reduces local inflammation and thus increases the ability to repair diabetic alveolar bone,showing promise for the treatment of alveolar defect in diabetic patients.

An anti-bacterial porous shape memory self-adaptive stiffened polymer for alveolar bone regeneration after tooth extraction

The regeneration of alveolar bone after tooth extraction is critical for the placement of dental implants.Developing a rigid porous scaffold with defect shape adaptability is of great importance but challenging for alveolar bone regeneration.Herein,we design and synthesize a biocompatible poly(L-glutamic acid)-g-poly(ε-caprolactone)(PLGA-g-PCL)porous shape memory(SM)polymer.The PLGA-g-PCL is then copolymerized with acryloyl chloride grafted poly(ω-pentadecalactone)(PPDLDA)having a higher phase transition temperature than shape recovery temperature to maintain stiffness after shape recovery to resist chewing force.The hybrid pol-ydopamine/silver/hydroxyapatite(PDA/Ag/HA)is coated to the surface of(PLGA-g-PCL)-PPDL scaffold to afford the anti-bacterial activity.The porous SM scaffold can be deformed into a compact size and administered into the socket cavity in a minimally invasive mode,and recover its original shape with a high stiffness at body tem-perature,fitting well in the socket defect.The SM scaffold exhibits robust antibacterial activity against Staphy-lococcus aureus(S.aureus).The porous microstructure and cytocompatibility of PLGA allow for the ingrowth and proliferation of stem cells,thus facilitating osteogenic differentiation.The micro-CT and histological analyses demonstrate that the scaffold boosts efficient new bone regeneration in the socket of rabbit mandibular first premolar.This porous shape memory self-adaptive stiffened polymer opens up a new avenue for alveolar bone regeneration.

Clinical efficacy,bone density,and follow-up in implant and orthodontic treatment for inclined adjacent teeth

BACKGROUND Tooth defects can cause elongation of occlusal teeth,leading to insufficient repair space.The combination of dental implant restoration and orthodontic treatment of oblique adjacent teeth has a significant therapeutic effect.AIM To explore clinical efficacy,bone density,and follow-up of implant and orthodontic treatment for patients with inclined adjacent teeth.METHODS In total,98 patients with oblique adjacent teeth were randomly assigned to implant restoration combined with orthodontic treatment(group A,n=49)or to receive implant restoration alone(group B,n=49).Changes in alveolar ridge bone density and apical bone density were observed before and after treatment in the two groups.Changes in chewing function and language function were compared between the two groups of patients.Follow-up lasted for 12 mo after repair to observe any adverse reactions in the oral cavity.RESULTS The clinical effective rates of group A and group B were 97.96%and 85.71%,respectively,with group A having a higher clinical effective rate than group B.After treatment,the bone density of the alveolar ridge and apical bone in both groups decreased compared to before treatment,while the chewing and language functions improved.The changes in various indicators in group A were more significant.After treatment,the satisfaction rate of group A(97.96%)was higher than that of group B(79.59%).The incidence of adverse reactions in group A(2.04%)was lower than that in group B(24.49%).CONCLUSION The amalgamation of implant restoration and orthodontic treatment for adjacent tilted teeth demonstrates notable clinical efficacy,diminishes alveolar bone resorption,and fosters patient functional rehabilitation while exhibiting negligible adverse reactions.

Three-dimensional evaluation of upper anterior alveolar bone dehiscence after incisor retraction and intrusion in adult patients with bimaxillary protrusion malocclusion

Objective:The purpose of this study was to evaluate three-dimensional(3D) dehiscence of upper anterior alveolar bone during incisor retraction and intrusion in adult patients with maximum anchorage.Methods:Twenty adult patients with bimaxillary dentoalveolar protrusion had the four first premolars extracted.Miniscrews were placed to provide maximum anchorage for upper incisor retraction and intrusion.A computed tomography(CT) scan was performed after placement of the miniscrews and treatment.The 3D reconstructions of pre-and post-CT data were used to assess the dehiscence of upper anterior alveolar bone.Results:The amounts of upper incisor retraction at the edge and apex were(7.64±1.68) and(3.91±2.10) mm,respectively,and(1.34±0.74) mm of upper central incisor intrusion.Upper alveolar bone height losses at labial alveolar ridge crest(LAC) and palatal alveolar ridge crest(PAC) were 0.543 and 2.612 mm,respectively,and the percentages were(6.49±3.54)% and(27.42±9.77)%,respectively.The shape deformations of LAC-labial cortex bending point(LBP) and PAC-palatal cortex bending point(PBP) were(15.37±5.20)° and(6.43±3.27)°,respectively.Conclusions:Thus,for adult patients with bimaxillary protrusion,mechanobiological response of anterior alveolus should be taken into account during incisor retraction and intrusion.Pursuit of maximum anchorage might lead to upper anterior alveolar bone loss.

Contour changes in human alveolar bone following tooth extraction of the maxillary central incisor

The purpose of this study was to apply cone-beam computed tomography （CBCT） to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original mor- phological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans （CBCT I and CBCT II）, one taken before and one taken three months after tooth extraction of maxillary central incisor （test tooth T）. A fixed anatomic reference point was used to orient the starting axial slice of the two scans. On three CBCT I axial slices, which represented the deep, middle, and shallow layers of the socket, labial and palatal alveolar bone widths of T were measured. The number of sagittal slices from the start point to the pulp centre of T was recorded. On three CBCT II axial slices, the pulp centres of extracted T were oriented according to the number of moved sagittal slices recorded in CBCT I. Labial and palatal alveolar bone widths at the oriented sites were measured. On the CBCT I axial slice which represented the middle layer of the socket, sagittal slices were reconstructed. Relevant distances of T on the sagittal slice were measured, as were the alveolar bone width and tooth length of the opposite central incisor. On the CBCT II axial slice, which represented the middle layer of the socket, relevant distances recorded in CBCT I were transferred on the sagittal slice. The height reduction of alveolar bone on labial and palatal sides was measured, as were the alveolar bone width and tooth length of the opposite central incisor at the oriented site. Intraobserver reliability assessed by intraclass correlation coefficients （ICCs） was high. Paired sample t-tests were performed. The alveolar bone width and tooth length of the opposite central incisor showed no statistical differences （P〈0.05）. The labial alveolar bone widths of T at the deep, middle, and shallow layers all showed statistical differences. However, no palatal alveolar bone widths showed any statistical differences. The width reduction of alveolar bone was 1.2, 1.6, and 2.7 mm at the deep, middle, and shallow layers, respectively. The height reduction of alveolar bone on labial and palatal sides of T both showed statistical differences, which was 1.9 and 1.1 mm, respectively.

Development of a multicellular 3D-bioprinted microtissue model of human periodontal ligament-alveolar bone biointerface:Towards a pre-clinical model of periodontal diseases and personalized periodontal tissue engineering

While periodontal (PD) disease is among principal causes of tooth loss worldwide, regulation of concomitant soft and mineralized PD tissues, and PD pathogenesis have not been completely clarified yet. Besides, relevant pre-clinical models and in vitro platforms have limitations in simulating human physiology. Here, we have harnessed three-dimensional bioprinting (3DBP) technology for developing a multi-cellular microtissue model resembling PD ligament-alveolar bone (PDL-AB) biointerface for the first time. 3DBP parameters were optimized;the physical, chemical, rheological, mechanical, and thermal properties of the constructs were assessed. Constructs containing gelatin methacryloyl (Gel-MA) and hydroxyapatite-magnetic iron oxide nanoparticles showed higher level of compressive strength when compared with that of Gel-MA constructs. Bioprinted self-supporting microtissue was cultured under flow in a microfluidic platform for >10 days without significant loss of shape fidelity. Confocal microscopy analysis indicated that encapsulated cells were homogenously distributed inside the matrix and preserved their viability for >7 days under microfluidic conditions. Immunofluorescence analysis showed the cohesion of stromal cell surface marker-1+ human PDL fibroblasts containing PDL layer with the osteocalcin+ human osteoblasts containing mineralized layer in time, demonstrating some permeability of the printed constructs to cell migration. Preliminary tetracycline interaction study indicated the uptake of model drug by the cells inside the 3D-microtissue. Also, the non-toxic levels of tetracycline were determined for the encapsulated cells. Thus, the effects of tetracyclines on PDL-AB have clinical significance for treating PD diseases. This 3D-bioprinted multi-cellular periodontal/osteoblastic microtissue model has potential as an in vitro platform for studying processes of the human PDL.

脂肪间充质干细胞过表达骨形态发生蛋白2促进骨质疏松大鼠牙槽骨缺损修复

背景:颌骨在骨质疏松症中最容易受累,脂肪间充质干细胞和骨形态发生蛋白2具有促进骨质疏松症骨再生的效果,然而骨形态发生蛋白2修饰的脂肪间充质干细胞对骨质疏松症牙槽骨缺损的修复作用鲜有报道。目的:探究过表达骨形态发生蛋白2的脂肪间充质干细胞对骨质疏松大鼠牙槽骨缺损的修复作用。方法:①将过表达骨形态发生蛋白2基因的慢病毒感染大鼠脂肪间充质干细胞,通过检测绿色荧光蛋白和骨形态发生蛋白2表达进行鉴定;②切除卵巢建立骨质疏松大鼠模型,于上颌两侧第一磨牙位置制备3 mm×3 mm×3 mm的圆柱形缺损;③假手术组和骨质疏松组大鼠植入明胶海绵,脂肪间充质干细胞组植入空载体慢病毒感染的脂肪间充质干细胞与明胶海绵复合体,过表达骨形态发生蛋白2的脂肪间充质干细胞组植入过表达骨形态发生蛋白2的脂肪间充质干细胞与明胶海绵复合体,1个月后进行相关指标检测。结果与结论:①脂肪间充质干细胞组和过表达骨形态发生蛋白2的脂肪间充质干细胞组转染效率均达到70%以上;与脂肪间充质干细胞组相比,过表达骨形态发生蛋白2的脂肪间充质干细胞组骨形态发生蛋白2蛋白表达水平明显升高(P<0.05);②假手术组骨缺损区可见大量新骨生成;与假手术组相比,骨质疏松组有少量新骨生成,新骨面积明显减小,碱性磷酸酶、骨钙素及骨形态发生蛋白2 mRNA和蛋白水平明显降低;与骨质疏松组相比,脂肪间充质干细胞组和过表达骨形态发生蛋白2的脂肪间充质干细胞组有大量新骨生成,新骨面积明显增加,碱性磷酸酶、骨钙素及骨形态发生蛋白2 mRNA和蛋白水平明显升高,且过表达骨形态发生蛋白2的脂肪间充质干细胞组优于脂肪间充质干细胞组(均P<0.05);③结果表明,骨形态发生蛋白2在骨质疏松大鼠牙槽骨表达较少,过表达骨形态发生蛋白2的脂肪间充质干细胞能够促进骨质疏松大鼠牙槽骨缺损的成骨再生。

隐形矫治器设计上切牙压低量对牙根吸收的影响分析

目的研究在隐形矫治技术中上颌中切牙的压低量与牙根吸收的关系。方法纳入于合肥市口腔医院正畸一科采用隐形矫治技术治疗深覆牙合的非拔牙患者62例,在正畸治疗前(T0)、压低量1 mm时(T1)和压低量2 mm时(T2)进行三次CBCT追踪检查。测量三个时期上切牙牙根长度、牙根体积和唇腭侧牙槽骨高度,运用SPSS 26.0软件进行统计学分析。结果牙根吸收与压低量呈正相关(P<0.05);压低量越大,切牙唇倾度越大(P<0.05);三个阶段的唇侧牙槽骨高度无统计学差异(P>0.05),腭侧牙槽骨高度的差异有统计学意义(P<0.05),T2期腭侧牙槽骨吸收明显;牙根吸收与治疗时间呈正相关(P<0.05)。结论隐形矫治技术中上颌中切牙牙根吸收与压低量有关。