[Imaging characteristic of Stafne bone cavity：a retrospective study based on cone-beam CT].

PURPOSE: To guide clinical decision-making more efficiently via collecting and analyzing the imaging data of patients with Stafne bone cavity(SBC). METHODS: Six patients with SBC were retrospectively reviewed in Stomatological Hospital of Shandong University. By assessing cone-beam CT (CBCT) data, age, sex, complaint, cavity location, diameter at three dimension, maximal cross-sectional area of multi-planar reconstruction planes, content gray scale, morphological classification and its relationship with mandibular canal were recorded respectively. RESULTS: A total of 6 cases were inadvertently found on CBCT, with no symptoms. The locations of SBC were between mandibular molar region and mandibular angle, inferior border of mandible and mandibular canal, mostly at lingual side. Three were on the left and three were on the right. The bone cavity was elliptic and its long axis was consistent with the long axis of the mandible, with an average long axis diameter of (16.43±4.54) mm, horizontal axis diameter of (6.91±1.48) mm, vertical axis diameter of (10.24±2.10) mm. According to the multi-planar reconstruction planes readings, the maximal cross-sectional area of the bone cavity was (91.93±25.52) mm2, the maximal coronal area was (57.26±23.23) mm2, and the maximal sagittal area was (127.80±51.22) mm2. In view of the classification in the relationship between SBC marginal line and buccal cortical bone, there were 2 cases of type I cavity, 3 cases of type II cavity and 1 case of type III cavity. The connection between the bone cavity and the surrounding anatomical structure was classified into 3 conditions: covering penetration, adjacency and separation on the basis of the relative position between the cavity boundary with the mandibular inferior margin and the mandibular canal in sagittal plane. In addition, the content type could be primarily identified depending on estimation of corrected grey scale in the center of bone cavity. CONCLUSIONS: CBCT can make an intuitive and clear diagnosis of Stafne bone cavity, which brings great significance into the early clinical decision-making, thus not only avoiding unnecessary surgery, reducing the waste of additional medical resources, but also decreasing the physical and mental trauma of patients.

An analysis of the optimal intrusion force of the maxillary central incisor with root horizontal resorption using the finite element method and curve fitting.

There are no studies on the optimal intrusion force in orthodontic patients with the existing root resorption (RR). The study aimed to analyze the optimal intrusion force for central incisors with existing horizontal root resorption using the finite element method (FEM). We calculated the optimal intrusion force using the finite element method and curve fitting. We found that with the increase of the maxillary central incisor's root horizontal resorption length, the optimal intrusion force interval's median gradually increases. If the resorption length is more significant than 1/2 of the root length, it is not recommended to use intrusion force theoretically.

A cone-beam computed tomography study of the root canal morphology of mandibular first premolars and the location of root canal orifices and apical foramina in a Chinese subpopulation.

INTRODUCTION: Successful root canal treatment is dependent on detailed knowledge of the morphology of the root canal system. The aim of this study was to investigate the morphology of the root canal systems of mandibular first premolars and the location of root canal orifices and apical foramina in a Chinese subpopulation using cone-beam computed tomography scanning. METHODS: A total of 440 cone-beam computed tomographic images of mandibular first premolars were obtained from 238 patients. Tooth position, root canal morphology, the distance between the apical foramen and the anatomic apex, and the distance between the 2 root canal orifices of mandibular first premolars with 2 root canals were investigated. The Fisher exact test was used to analyze the correlation between the number of root canals and tooth position. RESULTS: Overall, 1.14% (n = 5) of the teeth had a C-shaped root canal system, 77.14% (n = 335) had 1 root canal, and 22.05% (n = 97) had 2 root canals from type II to type V. The remaining 0.68% (n = 3) were classified as type VIII, which had 3 root canals. The most frequent distribution of the distance between the apical foramen and the anatomic apex in 335 mandibular first premolars with 1 root canal was 1-2 mm (n = 192). The distance between the apical foramen and the anatomic apex of mandibular first premolars with 2 root canals was in accord with that of mandibular first premolars with 1 root canal. The distance between the 2 root canal orifices of mandibular first premolars with 2 root canals was approximately 13 mm. CONCLUSIONS: Most mandibular first premolars had 1 root canal. More than 1 of 5 mandibular first premolars had complex root canal systems (with 2 or more root canals). This study provides supplemental information about the root canals of mandibular first premolars in a Chinese subpopulation.

Association between mandibular posterior alveolar morphology and growth pattern in a Chinese population with normal occlusion.

OBJECTIVE: To investigate the relationship between growth patterns and mandibular posterior tooth-alveolar bone complex morphology in a Chinese population with normal occlusion. METHODS: Forty-five patients with normal occlusion (23 males, 22 females) were included in this study. Among these patients, 20 displayed the vertical growth pattern, and 20 had the horizontal growth pattern, while the remaining patients displayed the average growth pattern. All of the patients underwent dental cone beam computed tomography (CBCT), which included the region of the mandibular posterior teeth and the alveolar. A linear regression analysis and a correlation analysis between the facial height index (FHI) and the alveolar bone morphology were performed. RESULTS: The inclination of the molars, the thickness of the cortical bone, and the height of the mandibular bone differed significantly between patients with the horizontal growth pattern and those with the vertical growth pattern (P<0.05). Significant positive correlations were found between: the FHI and the inclination of the molars; the FHI and the thickness of the cortical bone; and the FHI and the height of the mandibular bone. CONCLUSIONS: The mandibular posterior tooth-alveolar bone complex morphology may be affected by growth patterns.

[Anthropometric analysis of the mandible morphology in young females with different vertical skeletal pattern].

OBJECTIVE: The purpose of this study is to assess the height and width of mandibular cross-sections and the thickness of cortical bone for young females in different vertical skeletal pattern by cone beam CT (CBCT) and determine the characteristics and differences of mandible among different vertical skeletal patterns. METHODS: A total of 64 females, aged from 19 to 40 years old, were enrolled from Department of Orthodontics of School of Stomatology of Shandong University. After examination with CBCT scan, they were divided into 3 groups according to the vertical skeletal patterns (14 in low-angle group, 31 in average-angle group and 19 in high-angle group). The mandibular morphology was evaluated according to the height and width of the mandibular cross-sections and the thickness of cortices. SPSS 16.0 was used to analyze the characteristics and differences of mandible among different vertical skeletal patterns. RESULTS: The height of symphysis in the high-angle group was higher than that in the low-angle group, but the height of molars in the low-angle group was higher than that in the high-angle group (P<0.05). In the regions of anterior teeth and premolars, the width of upper one third of the mandibular cross-sections in the low-angle group was significantly larger than those in the high-angle group, while in the symphysis and lateral incisors regions, the width of lower one third of the mandibular cross-sections in the low-angle group was larger than those in the high-angle group (P<0.05). Except of the region of premolars, the cortical thickness of base in the low-angle group was significant thicker than those in the high-angle group (P<0.05). In the regions of canine, premolar and molar, the cortical thickness of buccal upper one third in the low-group was thicker than those in the high-angle group, but in the regions of canine and the second molar, the cortical thickness of buccal lower one third in the low-angle group was thi- cker than those in the high-angle group (P<0.05). In the regions of the symphysis, the cortical thickness of lingual lower one third in the low-angle group was thicker than those in the high-angle group (P<0.05), but in the regions of premolar and molar of lingual upper one third in the low-angle group was thicker than those in the high-angle group (P<0.05). CONCLUSION: The height and width of the cross-sections of the body of mandible differed more than thickness of cortical bone among the three different vertical skeletal patterns. The height of cross-sections decreases gradually from the anterior region to the posterior region in three groups. The width of cross-sections in the low-group is thicker than those in other two groups. The thickness of cortical bones decreases successively from low, average to high angle group.

A study of the distobuccal root canal orifice of the maxillary second molars in Chinese individuals evaluated by cone-beam computed tomography.

UNLABELLED: As is commonly understood, the root canal morphology of the maxillary molars is usually complex and variable. It is sometimes difficult to detect the distobuccal root canal orifice of a maxillary second molar with root canal treatment. No literature related to the distobuccal root canals of the maxillary second molars has been published. OBJECTIVE: To investigate the position of the distobuccal root canal orifice of the maxillary second molars in a Chinese population using cone-beam computed tomography (CBCT). MATERIAL AND METHODS: In total, 816 maxillary second molars from 408 patients were selected from a Chinese population and scanned using CBCT. The following information was recorded: (1) the number of root canals per tooth, (2) the distance between the mesiobuccal and distobuccal root canal orifice (DM), (3) the distance between the palatal and distobuccal root canal orifice (DP), (4) the angle formed by the mesiobuccal, distobuccal and palatal root canal orifices (∠PDM). DM, DP and ∠PDM of the teeth with three or four root canals were analyzed and evaluated. RESULTS: In total, 763 (93.51%) of 816 maxillary second molars had three or four root canals. The distance between the mesiobuccal and distobuccal orifice was 0.7 to 4.8 mm. 621 (81.39%) of 763 teeth were distributed within 1.5-3.0 mm. The distance between the palatal and distobuccal orifice ranged from 0.8 mm to 6.7 mm; 585 (76.67%) and were distributed within 3.0-5.0 mm. The angle (∠PDM) ranged from 69.4º to 174.7º in 708 samples (92.80%), the angle ranged from 90º to 140º. CONCLUSIONS: The position of the distobuccal root canal orifice of the maxillary second molars with 3 or 4 root canals in a Chinese population was complex and variable. Clinicians should have a thorough knowledge of the anatomy of the maxillary second molars.

Transcription factor osterix modified bone marrow mesenchymal stem cells enhance callus formation during distraction osteogenesis.

This study was designed to investigate the effects of local delivery of bone marrow mesenchymal stem cells (BMMSCs) with or without osterix (OSX) gene transfected on bone regeneration in the distracted zone using a rabbit model of mandibular lengthening. Fifty-four New Zealand white rabbits underwent osteodistraction of the left mandible and were then randomly divided into group A, group B, and group C (n = 18 for each group). At the end of distraction BMMSCs transfected with OSX, autologous BMMSCs and physiological saline were injected into the distraction gaps in groups A, B, and C, respectively. Nine animals from each group were humanely killed at 2 and 6 weeks after completion of distraction. The distracted mandibles were harvested and processed for radiographic, histological, and immunohistochemical examination. Excellent bone formation in the distracted callus was observed in group A and group B; the former showed better bone formation and highest bone mineral density (BMD), thickness of new trabeculae (TNT, mm) and volumes of the newly formed bone area (NBV) in the distraction zones. Group C animals showed poor bone formation in the distracted callus when compared with groups A and B. Positive immunostaining of bone sialoprotein (BSP) was observed in the distracted callus in all groups; however, BSP expression was much stronger in group A than in groups B and C. The results of this study suggest transplantation of BMMSCs can promote bone formation in DO; OSX-mediated ex vivo gene therapy was more effective during bone deposition and callus formation in distraction osteogenesis.

Transarterial embolization of a high-flow maxillary arteriovenous malformation fed by multiple arteries.

A high-flow maxillary arteriovenous malformation fed by multiple arteries, including bilateral internal maxillary arteries and ophthalmic artery, is reported. A combination of polyvinyl alcohol particles and N-butyl-cyanoacrylate mixed with lipiodol was progressively deposited within the distal vascular bed by transarterial superselective embolization of the branches of bilateral internal maxillary arteries, resulting in complete anatomic and clinical cure. The authors feel that this approach is more secure and effective compared with transfemoral venous embolization and direct transosseous puncture. It also avoids mutilating surgery.

[Mandibular keratocyst induced trigeminal neuralgia: report of one case].

Trigeminal neuralgia is very common in clinic, but the etiology is still unclear. This articles reported a case of trigeminal neuralgia induced by jaw keratocyst. The clinical manifestation, radiographic characteristic, pathologic diagnosis and treatment were discussed. It is concluded that jaw bone cavities may be one of the major etiologic factors of secondary trigeminal neuralgia. Surgical curettage of the lesion is the main treatment for this disease.

A study of the distobuccal root canal orifice of the maxillary second molars in Chinese individuals evaluated by cone-beam computed tomography

As is commonly understood, the root canal morphology of the maxillary molars is usually complex and variable. It is sometimes difficult to detect the distobuccal root canal orifice of a maxillary second molar with root canal treatment. No literature related to the distobuccal root canals of the maxillary second molars has been published. Objective: To investigate the position of the distobuccal root canal orifice of the maxillary second molars in a Chinese population using cone-beam computed tomography (CBCT). Material and methods: In total, 816 maxillary second molars from 408 patients were selected from a Chinese population and scanned using CBCT. The following information was recorded: (1) the number of root canals per tooth, (2) the distance between the mesiobuccal and distobuccal root canal orifice (DM), (3) the distance between the palatal and distobuccal root canal orifice (DP), (4) the angle formed by the mesiobuccal, distobuccal and palatal root canal orifices (∠PDM). DM, DP and ∠PDM of the teeth with three or four root canals were analyzed and evaluated. Results: In total, 763 (93.51%) of 816 maxillary second molars had three or four root canals. The distance between the mesiobuccal and distobuccal orifice was 0.7 to 4.8 mm. 621 (81.39%) of 763 teeth were distributed within 1.5-3.0 mm. The distance between the palatal and distobuccal orifice ranged from 0.8 mm to 6.7 mm; 585 (76.67%) and were distributed within 3.0-5.0 mm. The angle (∠PDM) ranged from 69. 4º to 174.7º in 708 samples (92.80%), the angle ranged from 90º to 140º. Conclusions: The position of the distobuccal root canal orifice of the maxillary second molars with 3 or 4 root canals in a Chinese population was complex and variable. Clinicians should have a thorough knowledge of the anatomy of the maxillary second molars.

[Repair of mandibular central fissures in rabbits with hBMP-2 gene modified tissue engineered bone].

PURPOSE: To evaluate the effectiveness of the tissue engineered bone substitute loaded with periosteal-derived osteoblasts (POBs) transfected by adenovirus mediated human bone morphogenetic protein-2 gene (Ad-hBMP-2) in the repair of rabbit mandibular central fissures. METHODS: 45 rabbits with the soft tissue in the mandibular central fissures removed were randomly divided into 5 groups, group I: Ad-hBMP-2 transfected POBs/bioglass group (n=10); group II: adenovirus mediated enhanced green fluorescent protein (Ad-EGFP) gene transfected POBs/bioglass group (n=10); group III: untransfected POBs/bioglass group (n=10); group IV: single bioglass group (n=10); group V: control group (n=5). The above bone substitutes were implanted in the rabbit mandibular central fissures respectively except group V. The samples were studied by gross, X-ray, histomorphology, histomorphometrical analysis and biomechanics after 2, 4, 8, 12 weeks respectively. One-way ANOVA was used for statistical analysis. RESULTS: In gross view, the rabbit mandibular central fissures in group I were replaced by new bone including cortical bone from the 4th week. X-ray examination showed that the higher bone density was found in the rabbit mandibular central fissures of group I 4 to 8 weeks after implantation. Histomorphometrical analysis showed much more new bony callus in group I than in other groups (P<0.01). The maximal anti-bending load and bending rigidity of the implanted bone substitute of group I were significantly higher than those of group II, III and IV (P<0.01). CONCLUSION: The tissue engineered bone substitute loaded with POBs transfected by human BMP-2 gene could get the best result in the repair of rabbit mandibular central fissures, therefore, it is likely to be used in the repair of alveolar clefts.

[Experimental study of mandibular periosteal distraction in rabbits].

OBJECTIVE: To investigate a novel technique for new bone formation--periosteal distraction osteogenesis. METHODS: A custom made periosteal distraction device was fixed to bilateral surface of the mandible in three rabbits. Periosteal distraction was performed on the left side of the mandible, the right side of the mandible served as the control. The animals were sacrificed at the end of distraction process. All the specimens were X-rayed and histologically examinated. RESULTS: All three animals survived with no obvious complications. Both in mass specimens and X-rays, there showed new bone formation on the distracted side of the mandible. In histological examinations, there was osteoblast-like cell infiltration and bone tissue formation in the distracted area. CONCLUSION: Periosteal distraction osteogenesis can provide a novel technique for the repair of bone defects.

[The experimental study of cryopreserved osteoblasts combined with BGC repairing mandibular defects in rabbits].

OBJECTIVE: The purpose of this study was to observe the biological characteristics of cultured Periosteal-derived Osteoblasts (POBs) preserved in liquid nitrogen in vitro, and to preliminarily study the osteogenetic capability of bioactive glass ceramic (BGC) combined with POBs. METHODS: The cryopreserved cells were cultured in DMEM medium and examined by morphological and histological assay. The POBs growing well in vitro were seeded into the porous BGC materials. A week later, the combined materials were implanted into the bone defects of rabbits' mandibular, the control groups were implanted into the single BGC (no cells). After 2, 4, 8, 12 weeks of operation, the specimens were respectively excised and examined by X-ray and histological chemistry. RESULTS: The cryopreserved POBs grew well in vitro and also had the tipical characteristics of mature osteoblasts. Cultured with BGC materials, the cells could attach, grow and proliferate well on the surface of most endoporous. After 4 weeks of operation, the transplanted osteoblasts began to form new osteoid or bone tissue in most pores of implanted BGC, and the bone defects were repaired better and earlier. CONCLUSION: It was practical to use the cryopreserved osteoblasts for further study on bone tissue engineering. It suggested that the "life active" bone would get more application and play a more important role in bone restoration and reconstruction.