Objective:To retrospectively analyze the pathogenic factors of retrograde peri-implantitis (RPI) and assess the effectiveness of treatment, and to provide clinicians evidence for the prevention and treatment of RPI.Methods:A total of 2 731 patients with missing teeth (4 016 implants) who underwent implant restoration in the Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical University between January 2004 and December 2022 were included in the study. According to the diagnostic criteria of RPI, a total of 20 cases (23 implants) of RPI were collected, including 4 female (5 implants) and 16 male (18 implants), and the treatment medical records, intraoral photos and cone beam CT or oral panoramic radiographs records of each patient were collected. Each patient with RPI was treated accordingly and followed up regularly to evaluate its efficacy.Results:After treatment, the follow-up time for 20 patients with clinical symptoms of RPI was 13 (6, 40) months (1 month to 13 years), and the survival rate of the treated implants was 91% (21/23). There were 7 patients (8 implants) with inactive RPI, no clinical symptoms, no loosening of the implant, with normal occlusal load, and the disease was at the inactive stage and was not treated. The pulp vitality of the natural tooth adjacent to the implant was normal, and the implant could function normally. There were 13 patients (15 implants) with infected RPI, 1 patient (1 implant) had no loosening of the implant, and the periapical radiolucency of the implant disappeared after endodontic treatment of the natural tooth adjacent to the implant; 12 patients (14 implants) had clinical symptoms such as implant loosening, pus discharge, etc. Among them, 10 patients (12 implants) were successfully implanted in situ or in adjacent sites after removing the implants, and were successfully implanted after 3 to 20 months. Two patients(2 implants) were removed and no further implants were placed. Among them, 2 implants with infected RPI had cystic lesions, which was similar to natural root apex cysts.Conclusions:The etiology of RPI is related to inflammation of adjacent tooth root tips or bacterial residues from inflammatory lesions in the alveolar bone and bone augmentation. RPI can be treated by perfect root canal treatment of adjacent teeth, removal of inflammatory tissue, or simultaneous guided bone regeneration techniques.

Objective:To retrospectively analyze the pathogenic factors of retrograde peri-implantitis (RPI) and assess the effectiveness of treatment, and to provide clinicians evidence for the prevention and treatment of RPI.Methods:A total of 2 731 patients with missing teeth (4 016 implants) who underwent implant restoration in the Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical University between January 2004 and December 2022 were included in the study. According to the diagnostic criteria of RPI, a total of 20 cases (23 implants) of RPI were collected, including 4 female (5 implants) and 16 male (18 implants), and the treatment medical records, intraoral photos and cone beam CT or oral panoramic radiographs records of each patient were collected. Each patient with RPI was treated accordingly and followed up regularly to evaluate its efficacy.Results:After treatment, the follow-up time for 20 patients with clinical symptoms of RPI was 13 (6, 40) months (1 month to 13 years), and the survival rate of the treated implants was 91% (21/23). There were 7 patients (8 implants) with inactive RPI, no clinical symptoms, no loosening of the implant, with normal occlusal load, and the disease was at the inactive stage and was not treated. The pulp vitality of the natural tooth adjacent to the implant was normal, and the implant could function normally. There were 13 patients (15 implants) with infected RPI, 1 patient (1 implant) had no loosening of the implant, and the periapical radiolucency of the implant disappeared after endodontic treatment of the natural tooth adjacent to the implant; 12 patients (14 implants) had clinical symptoms such as implant loosening, pus discharge, etc. Among them, 10 patients (12 implants) were successfully implanted in situ or in adjacent sites after removing the implants, and were successfully implanted after 3 to 20 months. Two patients(2 implants) were removed and no further implants were placed. Among them, 2 implants with infected RPI had cystic lesions, which was similar to natural root apex cysts.Conclusions:The etiology of RPI is related to inflammation of adjacent tooth root tips or bacterial residues from inflammatory lesions in the alveolar bone and bone augmentation. RPI can be treated by perfect root canal treatment of adjacent teeth, removal of inflammatory tissue, or simultaneous guided bone regeneration techniques.

OBJECTIVETo establish a miniature pig model of mandibular osteoradionecrosis (ORN).

METHODSA single dose of irradiation (IR25 Gy, 28 Gy) was delivered via an electronic linear accelerator to the right mandible of 24 miniature pigs by utilizing three dimensional conformal radiotherapy (3D-CRT). The first molar of the mandible was extracted 2 months after radiation. Mandibular ORN was diagnosed through gross observation, X-ray film, CT, and histopathologic examination.

RESULTSAt 3-4 months after radiation, all animals suffered from mandibular ORN after dental extraction. The symptoms of ORN were more severe in the 28 Gy group than in the 25 Gy group.

CONCLUSIONA miniature pig model of mandibular ORN can be established through 25 Gy irradiation + dental extraction.

Animals ; Mandible ; Mandibular Diseases ; pathology ; Molar ; Osteoradionecrosis ; pathology ; Particle Accelerators ; Radiation Injuries, Experimental ; pathology ; Radiotherapy, Conformal ; adverse effects ; Swine ; Swine, Miniature ; Tooth Extraction

Objective To investigate the treatment effect of mandibular osteoradionecrosis(ORN) by autologous bone marrow mesenchymal stem cells(BMMSC) in miniature pigs.Methods Six miniature pigs with mandibular ORN(25 Gy) were used.BMMSC were separated and cultured in vitro and then implanted on to the premolded hydroxyapatite-tricalcium phosphate(HA-TCP).The BMMSC-HA-TCP complexes were implanted into the defective area of mandibular ORN in 4 animals.Implantation of only HA-TCP in 2 animals served as control.Gross observation, spiral CT, coronary CT and histopathologic examination were carried out.Results Fistula disappeared in animals with BMMSC-HA-TCP complexes 3 months after implantation, while fistula was found in controls.Spiral CT analysis showed that cortical bone repair were found 4 months after BMMSC-HA-TCP complexes implantation, while bone damage(cortical and cancellous bone fracture) increased in controls.Histopathologic examination revealed that 4 months later after BMMSC-HA-TCP complexes implantation, new bone formation and bone cells could be observed, but there was a large number of fibrous tissue and no new bone in controls.Conclusions Transplantation of autologous BMMSC with HA-TCP may have therapeutic effect in the treatment of mandibular ORN.

OBJECTIVETo investigate the effect of Eucommiol on osteogenic differentiation of adipose-derived stem cells (ADSCs), and the feasibility of applying in mandibular defects repair using ADSCs combined with the extract of Eucommiol scaffold material.

METHODSForty-eight New Zealand rabbits were randomly divided into four groups and bilateral mandibular defect was prepared. Group A: Implanted the ADSCs combined with the extract of Eucommiol scaffold, group B: Implanted the ADSCs combined with hydroxyapatite materials, group C: Implanted hydroxyapatite materials, group D: The control group. All the experimental animals were sacrificed after 2, 4, 8, 12 weeks. Tissue samples were observed by gross observation, radiographic analysis, hematoxylin-eosin (HE) staining, scanning electron microscope (SEM). The value of imaging analysis and osteogenesis were evaluated. The results were analyzed by SPSS 17.0 statistical software.

RESULTSIn vivo imaging and histological staining showed that the healing of bone defect and bone quality in group A was significantly better than those in the other groups. SEM showed well biocompatibility between composite material and tissue without inflammation reaction. By measuring and analyzing the dental CT data and new bone area, the bone in group A was obviously better than those in other groups (P < 0.05).

CONCLUSIONThe extract of Eucommiol can promote ADSCs into bone cells. The role of ADSCs combined with extract of Eucommiol scaffold materials has significant bone induction. It is expected that this material could become a new composite material and be used to fix the jaw bone defects.

Adipocytes ; Alcohols ; Animals ; Bone and Bones ; Cell Differentiation ; Cells, Cultured ; Cyclopentanes ; Durapatite ; Mandible ; Osteogenesis ; Rabbits ; Stem Cells ; Tissue Engineering ; Tissue Scaffolds

Objective To compare the three-dimensional eephalometric and three-dimensional CT measurements of adult zygomatic complex among a Sanjiang population.Methods 120 female natives of Sanjiang region from Chinese Han between 19 to 23 years of age (mean 21.4 years),were randomly selected from students of Jiamusi University.Three-dimensional cephalometric and CT measurements of the face and skull were taken,with reference to zygomatic size measurement by Prof.Qi Zuo-liang,for the comparative study, which included the upper,mid and lower facial width followed by the length,width and angle of malar process,and width of the facial bone.Statistical analysis was done with the obtained measurements.Results Three-dimensional CT analysis showed facial width ratio of 0.83 and 0.79 and skeletal facial profile width ratio of 0.81 and 0.77,respectively,when compared with three-dimensional cephalometric analysis that showed facial width ratio of 0.84 and 0.77.Both values showed no statistical significance (P>0.05).Conclusion Three-dimensional CT measurement as the same to three-dimensional cephalometric can be used in the diagnosis of prominent malar complex.