Tissue interactions play a crucial role in tooth development.Notably,extracellular vesicle-mediated interactions between the mandible and tooth germ are considered essential.Here,we revealed that mandible extracellula...Tissue interactions play a crucial role in tooth development.Notably,extracellular vesicle-mediated interactions between the mandible and tooth germ are considered essential.Here,we revealed that mandible extracellular vesicles could modulate the proliferation and differentiation of dental mesenchymal cells by regulating the histone demethylase KDM2B.Further investigation showed that mandible derived extracellular vesicles could deliver miR-206 to KDM2B,thereby regulating tooth development.An animal study demonstrated that the miR-206/KDM2B pathway affected tooth morphogenesis and mineralization after eight weeks of subcutaneous transplantation in nude mice.In conclusion,this study suggested that the mandible played a critical role in tooth morphogenesis and mineralization,which could be a potential therapeutic target for abnormal tooth development and an alternative model for tooth regeneration.展开更多
Didelphid marsupials are considered a morphologically unspecialized group with a generalist diet that includes vertebrates,invertebrates,and plant matter.While cranium and scapula variation has alreadybeen examined wi...Didelphid marsupials are considered a morphologically unspecialized group with a generalist diet that includes vertebrates,invertebrates,and plant matter.While cranium and scapula variation has alreadybeen examined within Didelphidae,variation inmandible shape,usually associated with diet or phylogeny in other mammalian groups,has not yet been properly assessed in the family.We evaluated the variation in mandible shape and size of didelphids(2470 specimens belonging to 94 species)using 2D geometric morphometrics.We classified the diet of the didel-phids into four broad categories to assess whether morphospace ordination relates to dietary habits.We also provided the most comprehensive phylogeny for the family(i23 out of the 126 living species)using 10 nuclear and mitochondrial genes.We then mapped mandible size and shape onto that phylogeny for 93 selected taxa and ancestral size and shapes were reconstructed by parsimony.We found phylogenetically structured variation in mandible morphology between didelphid groups,and our results indicate that they have a significant phylogenetic signal.The main axis of shape variation is poorly related to size,but the second is strongly allometric,indicating that allometry is not the main factor in shaping morphological diversity on their mandibles.Our results indicate that the shape and size of the ancestral mandible of didelphids would be similar to that of the current species of the genus Marmosa.展开更多
Background:The increasing incidence of radiation-induced osteosarcoma of the maxilla and mandible(RIOSM) has become a significant problem that can limit long-term survival.The purpose of this study was to analyze the ...Background:The increasing incidence of radiation-induced osteosarcoma of the maxilla and mandible(RIOSM) has become a significant problem that can limit long-term survival.The purpose of this study was to analyze the association of clinicopathologic characteristics with treatment outcomes and prognostic factors of patients who developed RIOSM after undergoing radiotherapy for nasopharyngeal carcinoma(NPC).Methods:We reviewed the medical records of 53,760 NPC patients admitted to Sun Yat-sen University Cancer Center during the period August 1964 to August 2012.Of these patients,47 who developed RISOM and met inclusion criteria were included in this study.Two of these 47 patients refused treatment and were then excluded.Results:For all patients treated for NPC at Sun Yat-sen University Cancer Center during the study period,the total incidence of RIOSM after radiotherapy was 0.084%(47/53,760).Two patients(4.4%) had metastases at the diagnosis of RIOSM.Thirty-nine of the 45(86.7%) patients underwent surgery for RIOSM;most patients(24/39;61.5%) who underwent resection had gross clear margins,with 15 patients(38.5%) having either a gross or microscopic positive margin.All patients died.The 1-,2-,and 3-year overall survival(OS) rates for the entire cohort of 45 patients were 53.3%,35.6%and 13.5%,respectively.The independent prognostic factors associated with high OS rate were tumor size and treatment type.Conclusions:RISOM after radiotherapy for NPC is aggressive and often eludes early detection and timely intervention.Surgery combined with postoperative chemotherapy might be an effective treatment to improve patient survival.展开更多
Objective： To investigate the stress distribution to the mandible, with and without impacted third molars（IM3 s） at various orientations, resulting from a 2000-Newton impact force either from the anterior midline o...Objective： To investigate the stress distribution to the mandible, with and without impacted third molars（IM3 s） at various orientations, resulting from a 2000-Newton impact force either from the anterior midline or from the body of the mandible. Materials and methods： A 3 D mandibular virtual model from a healthy dentate patient was created and the mechanical properties of the mandible were categorized to 9 levels based on the Hounsfield unit measured from computed tomography（CT） images. Von Mises stress distributions to the mandibular angle and condylar areas from static impact forces（Load I-front blow and Load II left blow） were evaluated using finite element analysis（FEA）. Six groups with IM3 were included： full horizontal bony, full vertical bony, full 450 mesioangular bony, partial horizontal bony, partial vertical, and partial 450 mesioangular bony impaction, and a baseline group with no third molars. Results： Von Mises stresses in the condyle and angle areas were higher for partially than for fully impacted third molars under both loading conditions, with partial horizontal IM3 showing the highest fracture risk. Stresses were higher on the contralateral than on the ipsilateral side. Under Load II, the angle area had the highest stress for various orientations of IM3 s. The condylar region had the highest stress when IM3 s were absent. Conclusions： High-impact forces are more likely to cause condylar rather than angular fracture when IM3 s are missing. The risk of mandibular fracture is higher for partially than fully impacted third molars, with the angulation of impaction having little effect on facture risk.展开更多
Objective:To investigate the feasibility of a finite element model as an ideal research tool for human maxillofacial gunshot wounds.Methods:Mandible CT scan data on the Chinese Visible Human were imported into MIMICS ...Objective:To investigate the feasibility of a finite element model as an ideal research tool for human maxillofacial gunshot wounds.Methods:Mandible CT scan data on the Chinese Visible Human were imported into MIMICS software to obtain the surface mesh of the mandible.Then,these surface-meshed models were imported into ANSA software for automatic net generation.Elements and nodes were partitioned on the basis of the mesh to obtain a three-dimensional finite element model for the mandible with every internal parameter consistent with those of our previously developed model in the pig mandible.The finite element model was imported into LS-DYNA for computation.Finally,the LS-POST was used to complete the simulation and the measurements.Results:A three-dimensional finite element model was successfully established for gunshot wounds in the human mandible.The stress distribution and the degree of injury were simulated dynamically for shots from two types of projectiles in the mandible at one entry angle and at three impact velocities.Conclusion:Three-dimensional finite element models will become ideal research tools for treatment of ballistic wounds of the human maxillofacial region.Using this human mandibular model as a foundation,we will be able to successfully develop three-dimensional finite element models for human maxillofacial gunshot wounds.展开更多
BACKGROUND In atrophic posterior mandibular areas,where the bone height superior to the inferior alveolar nerve(IAN)is less than 6 mm,short implants are not applicable.Conventional alternatives such as IAN transpositi...BACKGROUND In atrophic posterior mandibular areas,where the bone height superior to the inferior alveolar nerve(IAN)is less than 6 mm,short implants are not applicable.Conventional alternatives such as IAN transposition and various alveolar bone augmentation approaches are technically demanding and prone to complications.CASE SUMMARY Computer-guided dynamic navigation implantation improves the accuracy,predictability,and safety of implant placement.This case report presents a dynamic navigation system-guided trans-IAN implant placement technique,which can successfully treat a posterior mandibular dentition defect when the bone height is only 4.5 mm.The implant was inserted into the buccal side of the IAN and was 1.7 mm away from the IAN.The implantation deviations were controlled within a satisfying range,and the long-term restoration outcome was stable.CONCLUSION Dynamic navigation system-guided trans-IAN implant placement might be a recommended technique for patients with extremely insufficient residual bone height and sufficient bone width in the posterior mandibular area.展开更多
CONTEXT: Stafne’s bone defect is a benign lesion appearing on the image as a round radiolucent lesion within a cortical defect on the mandible. CASE REPORT: We attend one 46-year-old male patient came for diagnostic ...CONTEXT: Stafne’s bone defect is a benign lesion appearing on the image as a round radiolucent lesion within a cortical defect on the mandible. CASE REPORT: We attend one 46-year-old male patient came for diagnostic evaluation of a rounded and radiolucent lesion in the transition of the subcondylar region and neck of the left mandible ramus incidentally found by a dentist. Computed tomography and magnetic resonance imaging were performed in medical radiology and a Stafne’s cyst was diagnosed in an atypical location. CONCLUSION: We emphasize that Stafne’s bone defect is a benign lesion, whose imaging diagnosis can be conclusive, avoiding unnecessary surgical procedures.展开更多
Aim This paper deals with the treatment of an atrophied toothless mandible with a fixing bridge carried by two nonstandard implant systems. Methodology Four bicortical screws were implanted into the frontal part of th...Aim This paper deals with the treatment of an atrophied toothless mandible with a fixing bridge carried by two nonstandard implant systems. Methodology Four bicortical screws were implanted into the frontal part of the mandible and one implant on each side was placed into the distal area of the mandible as a support for a fixing bridge. Results During the years 2002–2007 the authors placed a total of 256 bicortical screw and 84 blade implants. During this period only four bicortical screws and one blade implant failed. The primary and secondary surgical success rate was therefore above 98%, while the prosthetic success rate was 100%. （Bridges which had to be re-fabricated due to implant failure were not taken into account.） Conclusion This approach is recommended as a highly successful and affordable option for a wide range of patients.展开更多
Mandibular advancement devices(MADs)are one of the treatments used for Obstructive sleep apnea(OSA).MADs try to maintain the mandible in an advanced position to keep the upper airways open when sleeping.To achieve thi...Mandibular advancement devices(MADs)are one of the treatments used for Obstructive sleep apnea(OSA).MADs try to maintain the mandible in an advanced position to keep the upper airways open when sleeping.To achieve this goal,most current MADs limit the mouth opening to a few millimetres.The study of the kinematic behaviour of the patient’s jaw is essential in order to design devices that allow greater aperture ranges.For this purpose,a 3D multibody model that reproduces jaw movement has been developed in this work.To this end,the movement of the lower incisor has been determined by means of a vision system and reflective markers.In addition,the kinematics of the temporomandibular joint has been modelled.Next,the device is designed and printed using a cam-follower mechanism.This way,the cam profiles and the followers are optimally designed and positioned for each patient depending on the physiognomy of the jaw and the opening and advancing movement prescribed by the specialist.展开更多
Ameloblastoma is a benign but locally aggressive odontogenic neoplasm that accounts for 10% of all tumors arising in the mandible and maxilla (1). Eighty percent of ameloblastomas arise in the mandible, and they are u...Ameloblastoma is a benign but locally aggressive odontogenic neoplasm that accounts for 10% of all tumors arising in the mandible and maxilla (1). Eighty percent of ameloblastomas arise in the mandible, and they are usually found in young adults. It frequently recurs if not adequately展开更多
This study presents a reliable method for the semi-automatic generation of an FE model, which determines both geometrical data and bone properties from patient CT scans.3D FE analysis is one of the best approaches to ...This study presents a reliable method for the semi-automatic generation of an FE model, which determines both geometrical data and bone properties from patient CT scans.3D FE analysis is one of the best approaches to predict the stress and strain distribution in complex bone structures, but its accuracy strongly depends on the precision of input information. In geometric reconstruction, various methods of image processing, geometric modeling and finite element analysis are combined and extended. Emphasis is given to the assignment of the material properties based on the density values computed from CT data. Through this technique, the model with high geometric and material similarities were generated in an easy way. Consequently, the patient-specific FE model from mandible CT data is realized also.展开更多
Mesenchymal stromal cells(MSCs)are cells with the characteristic ability of self-renewal along with the ability to exhibit multilineage differentiation.Bone marrow(BM)is the first tissue in which MSCs were identified ...Mesenchymal stromal cells(MSCs)are cells with the characteristic ability of self-renewal along with the ability to exhibit multilineage differentiation.Bone marrow(BM)is the first tissue in which MSCs were identified and BM-MSCs are most commonly used among various MSCs in clinical settings.MSCs can stimulate and promote osseous regeneration.Due to the difference in the development of long bones and craniofacial bones,the mandibular-derived MSCs(M-MSCs)have distinct differentiation characteristics as compared to that of long bones.Both mandibular and long bone-derived MSCs are positive for MSC-associated markers such as CD-73,-105,and-106,stage-specific embryonic antigen 4 and Octamer-4,and negative for hematopoietic markers such as CD-14.展开更多
This report,"Mandible exosomal ssc-mir-133b regulates tooth development in miniature swine via endogenous apoptosis" by Li et al. is an important step forward in describing the factors that control tooth dev...This report,"Mandible exosomal ssc-mir-133b regulates tooth development in miniature swine via endogenous apoptosis" by Li et al. is an important step forward in describing the factors that control tooth development in a large animal model. That many of the regulatory miRNA pathways have been elucidated in murine species have always begged the question as to how relevant they展开更多
Spindle cell carcinoma is a rare highly malignant squamous cell carcinoma.Here,we describe a case of a 74-yearold Chinese female who presented with a 2-week history of pain and swelling in the left retromolar region.S...Spindle cell carcinoma is a rare highly malignant squamous cell carcinoma.Here,we describe a case of a 74-yearold Chinese female who presented with a 2-week history of pain and swelling in the left retromolar region.Surgical resection and titanium plate prosthesis were performed and histological analysis revealed spindle squamous cell carcinoma.展开更多
The present author made comparisons between the mandibular fragment and teeth attached on it from longgupo,Wushan on one side,and the corresponding specimens of early \%Homo\% of East Africa,\%Homo erectus\% from Dman...The present author made comparisons between the mandibular fragment and teeth attached on it from longgupo,Wushan on one side,and the corresponding specimens of early \%Homo\% of East Africa,\%Homo erectus\% from Dmanisi and \%Lufengpithecus \% from Yuanmou on other side.The results showed that the size of Wushan specimens are much smaller than those of early \%Homo\% of East Africa and Dmanisi mandible,and are concordant with that of \%Lufengpithecus \%from Yuanmou.Most of the characters which have been used to attribute Wushan mandible to \%Homo \%by some scholars,are shared by both hominid and ape. Among these characters,bifurcation of the root of the premolar is one of the characters of \%Lufengpithecus\% and seldom seen in hominid.The position of the anterior contact facet and the ratio of the length of talonid to that of the crown of Wushan premolar are characteristic in ape.Among the ape fossils avaliable in China \%Lufengpithecus \% is the closest relative of Wushan ape.Whether they have ancestor\|descendant relation is waiting for more findings to prove.展开更多
<b><span style="font-family:Verdana;">Background</span></b><span style="font-family:Verdana;">: Tuberculosis is a granulomatous infectious disease which is still being...<b><span style="font-family:Verdana;">Background</span></b><span style="font-family:Verdana;">: Tuberculosis is a granulomatous infectious disease which is still being a real health problem in developing countries. Mainly, this specific infection affects pulmonary sites, but, the occurrence in extra-pulmonary sites is more and more reported. However, when extra-pulmonary tuberculosis af</span><span style="font-family:Verdana;">fects the cervico-facial region, the cervical lymph nodes are the most in</span><span style="font-family:Verdana;"><span style="font-family:Verdana;">volved. </span><b></b></span><b><b><span style="font-family:Verdana;">Aim</span></b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> Throughout this case report, we put emphasis on keeping in mind of the possible tuberculous infection in a chronic lesion of mandible in children. </span><b><b><span style="font-family:Verdana;">Case presentation</span></b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> In this article, we present a case of a 2-year-old child who was complaining of swelling of the right angle of the mandible. The com</span><span style="font-family:Verdana;">puted tomography showed an osteolytic lesion suggesting tuberculous os</span><span style="font-family:Verdana;">teomyelitis but didn’t rule out a bony malignant neoplasm of the mandible. The histological examination of biopsy of the lesion proved the tuberculous osteomye</span><span style="font-family:Verdana;">litis of the mandible. The child has received anti-tubercular therapy for 9</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"> months, and she marked a good recovery. </span><b></b></span><b><b><span style="font-family:Verdana;">Conclusion</span></b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> In children, tuberculous osteomyelitis of the mandible is a curable disease without sequel when diagnosis is given at the right time.</span>展开更多
BACKGROUND Neurofibromas are benign tumors of a neurogenic origin.If these tumors occur without any other signs of neurofibromatosis,they are classified as isolated neurofibromas.Neurofibromas in the oral cavity mostl...BACKGROUND Neurofibromas are benign tumors of a neurogenic origin.If these tumors occur without any other signs of neurofibromatosis,they are classified as isolated neurofibromas.Neurofibromas in the oral cavity mostly occur within soft tissues,indicating that solitary intraosseous neurofibromas in the mandible are rare.Due to the absence of specific clinical manifestations,early diagnosis and treatment of these tumors are difficult to achieve.CASE SUMMARY A 37-year-old female patient visited our hospital due to numbness and swelling of the gums in the right lower molar area that had persisted for half a month.The patient’s overall condition and intraoral examination revealed no significant abnormalities.She was initially diagnosed with a cystic lesion in the right mandible.However,after a more thorough examination,the final pathological diagnosis was confirmed to be neurofibroma.Complete tumor resection and partial removal of the right inferior alveolar nerve were performed.As of writing this report,there have been no signs of tumor recurrence for nine months following the surgery.CONCLUSION This case report discusses the key features that are useful for differentiating solitary intraosseous neurofibromas from other cystic lesions.展开更多
Background: In forensic science the identification of a human is based on three important factors: Age, Sex and Stature. Bones are an important tool for it and among human bones the pelvis and the skull are the most r...Background: In forensic science the identification of a human is based on three important factors: Age, Sex and Stature. Bones are an important tool for it and among human bones the pelvis and the skull are the most reliable source for sex determination. In the absence of complete pelvis, mandi-ble becomes the important source for sex determination since mandible is the most durable and movable part of skull that can resist postmortem changes. The present study is conducted to assess the accuracy and role of few metric and morphological parameters in determination of the sex of dry adult human mandible of North Indian origin. Material & Methods: The Study is conducted on 50 dry intact human adult mandibles of North Indian origin. The metric parameters i.e. bigonial breadth, bicondylar breadth are measured with a Vernier Calliper by two observers. Non-metric parameters being observed are the morphological features like gonion flaring, muscular markings and shape of angle of symphysis menti. Result & Conclusion: It is concluded that bigonial breadth and bicondylar breadth exhibit the sexual dimorphism. Morphological Parameters: Gonion flaring, muscular markings and shape of angle of symphysis menti also demonstrate the sexual dimorphism. These parameters taken together may determine the sex of adult human mandibles. The present study shows that the mandible is an important tool in the determination of gender with high accuracy.展开更多
Progressive bone marrow failure and development of malignancies, particularly acute myeloid leukemia and solid tumors the most important features of Fan- coni’s Anemia (FA). This paper reports the case of a 16-year-o...Progressive bone marrow failure and development of malignancies, particularly acute myeloid leukemia and solid tumors the most important features of Fan- coni’s Anemia (FA). This paper reports the case of a 16-year-old patient with FA who developped squa- mous cell carcinoma of the mandible, ten years after the bone marrow transplantation (BMT).展开更多
基金supported by the National Natural Science Foundation of China(No.82071078,82370939)the Shaanxi Provincial High-level Talent Program and Young Talent Support Plan of Xi’an Jiaotong University.
文摘Tissue interactions play a crucial role in tooth development.Notably,extracellular vesicle-mediated interactions between the mandible and tooth germ are considered essential.Here,we revealed that mandible extracellular vesicles could modulate the proliferation and differentiation of dental mesenchymal cells by regulating the histone demethylase KDM2B.Further investigation showed that mandible derived extracellular vesicles could deliver miR-206 to KDM2B,thereby regulating tooth development.An animal study demonstrated that the miR-206/KDM2B pathway affected tooth morphogenesis and mineralization after eight weeks of subcutaneous transplantation in nude mice.In conclusion,this study suggested that the mandible played a critical role in tooth morphogenesis and mineralization,which could be a potential therapeutic target for abnormal tooth development and an alternative model for tooth regeneration.
文摘Didelphid marsupials are considered a morphologically unspecialized group with a generalist diet that includes vertebrates,invertebrates,and plant matter.While cranium and scapula variation has alreadybeen examined within Didelphidae,variation inmandible shape,usually associated with diet or phylogeny in other mammalian groups,has not yet been properly assessed in the family.We evaluated the variation in mandible shape and size of didelphids(2470 specimens belonging to 94 species)using 2D geometric morphometrics.We classified the diet of the didel-phids into four broad categories to assess whether morphospace ordination relates to dietary habits.We also provided the most comprehensive phylogeny for the family(i23 out of the 126 living species)using 10 nuclear and mitochondrial genes.We then mapped mandible size and shape onto that phylogeny for 93 selected taxa and ancestral size and shapes were reconstructed by parsimony.We found phylogenetically structured variation in mandible morphology between didelphid groups,and our results indicate that they have a significant phylogenetic signal.The main axis of shape variation is poorly related to size,but the second is strongly allometric,indicating that allometry is not the main factor in shaping morphological diversity on their mandibles.Our results indicate that the shape and size of the ancestral mandible of didelphids would be similar to that of the current species of the genus Marmosa.
文摘Background:The increasing incidence of radiation-induced osteosarcoma of the maxilla and mandible(RIOSM) has become a significant problem that can limit long-term survival.The purpose of this study was to analyze the association of clinicopathologic characteristics with treatment outcomes and prognostic factors of patients who developed RIOSM after undergoing radiotherapy for nasopharyngeal carcinoma(NPC).Methods:We reviewed the medical records of 53,760 NPC patients admitted to Sun Yat-sen University Cancer Center during the period August 1964 to August 2012.Of these patients,47 who developed RISOM and met inclusion criteria were included in this study.Two of these 47 patients refused treatment and were then excluded.Results:For all patients treated for NPC at Sun Yat-sen University Cancer Center during the study period,the total incidence of RIOSM after radiotherapy was 0.084%(47/53,760).Two patients(4.4%) had metastases at the diagnosis of RIOSM.Thirty-nine of the 45(86.7%) patients underwent surgery for RIOSM;most patients(24/39;61.5%) who underwent resection had gross clear margins,with 15 patients(38.5%) having either a gross or microscopic positive margin.All patients died.The 1-,2-,and 3-year overall survival(OS) rates for the entire cohort of 45 patients were 53.3%,35.6%and 13.5%,respectively.The independent prognostic factors associated with high OS rate were tumor size and treatment type.Conclusions:RISOM after radiotherapy for NPC is aggressive and often eludes early detection and timely intervention.Surgery combined with postoperative chemotherapy might be an effective treatment to improve patient survival.
基金Project supported by the National Natural Science Foundation of China(Nos.51375453 and 51775506)the Natural Science Foundation of Zhejiang Province(No.LY18E050022),China
文摘Objective： To investigate the stress distribution to the mandible, with and without impacted third molars（IM3 s） at various orientations, resulting from a 2000-Newton impact force either from the anterior midline or from the body of the mandible. Materials and methods： A 3 D mandibular virtual model from a healthy dentate patient was created and the mechanical properties of the mandible were categorized to 9 levels based on the Hounsfield unit measured from computed tomography（CT） images. Von Mises stress distributions to the mandibular angle and condylar areas from static impact forces（Load I-front blow and Load II left blow） were evaluated using finite element analysis（FEA）. Six groups with IM3 were included： full horizontal bony, full vertical bony, full 450 mesioangular bony, partial horizontal bony, partial vertical, and partial 450 mesioangular bony impaction, and a baseline group with no third molars. Results： Von Mises stresses in the condyle and angle areas were higher for partially than for fully impacted third molars under both loading conditions, with partial horizontal IM3 showing the highest fracture risk. Stresses were higher on the contralateral than on the ipsilateral side. Under Load II, the angle area had the highest stress for various orientations of IM3 s. The condylar region had the highest stress when IM3 s were absent. Conclusions： High-impact forces are more likely to cause condylar rather than angular fracture when IM3 s are missing. The risk of mandibular fracture is higher for partially than fully impacted third molars, with the angulation of impaction having little effect on facture risk.
文摘Objective:To investigate the feasibility of a finite element model as an ideal research tool for human maxillofacial gunshot wounds.Methods:Mandible CT scan data on the Chinese Visible Human were imported into MIMICS software to obtain the surface mesh of the mandible.Then,these surface-meshed models were imported into ANSA software for automatic net generation.Elements and nodes were partitioned on the basis of the mesh to obtain a three-dimensional finite element model for the mandible with every internal parameter consistent with those of our previously developed model in the pig mandible.The finite element model was imported into LS-DYNA for computation.Finally,the LS-POST was used to complete the simulation and the measurements.Results:A three-dimensional finite element model was successfully established for gunshot wounds in the human mandible.The stress distribution and the degree of injury were simulated dynamically for shots from two types of projectiles in the mandible at one entry angle and at three impact velocities.Conclusion:Three-dimensional finite element models will become ideal research tools for treatment of ballistic wounds of the human maxillofacial region.Using this human mandibular model as a foundation,we will be able to successfully develop three-dimensional finite element models for human maxillofacial gunshot wounds.
基金Supported by Clinical New Technology and New Business Project (2021)School and Hospital of Stomatology of Wuhan University
文摘BACKGROUND In atrophic posterior mandibular areas,where the bone height superior to the inferior alveolar nerve(IAN)is less than 6 mm,short implants are not applicable.Conventional alternatives such as IAN transposition and various alveolar bone augmentation approaches are technically demanding and prone to complications.CASE SUMMARY Computer-guided dynamic navigation implantation improves the accuracy,predictability,and safety of implant placement.This case report presents a dynamic navigation system-guided trans-IAN implant placement technique,which can successfully treat a posterior mandibular dentition defect when the bone height is only 4.5 mm.The implant was inserted into the buccal side of the IAN and was 1.7 mm away from the IAN.The implantation deviations were controlled within a satisfying range,and the long-term restoration outcome was stable.CONCLUSION Dynamic navigation system-guided trans-IAN implant placement might be a recommended technique for patients with extremely insufficient residual bone height and sufficient bone width in the posterior mandibular area.
文摘CONTEXT: Stafne’s bone defect is a benign lesion appearing on the image as a round radiolucent lesion within a cortical defect on the mandible. CASE REPORT: We attend one 46-year-old male patient came for diagnostic evaluation of a rounded and radiolucent lesion in the transition of the subcondylar region and neck of the left mandible ramus incidentally found by a dentist. Computed tomography and magnetic resonance imaging were performed in medical radiology and a Stafne’s cyst was diagnosed in an atypical location. CONCLUSION: We emphasize that Stafne’s bone defect is a benign lesion, whose imaging diagnosis can be conclusive, avoiding unnecessary surgical procedures.
文摘Aim This paper deals with the treatment of an atrophied toothless mandible with a fixing bridge carried by two nonstandard implant systems. Methodology Four bicortical screws were implanted into the frontal part of the mandible and one implant on each side was placed into the distal area of the mandible as a support for a fixing bridge. Results During the years 2002–2007 the authors placed a total of 256 bicortical screw and 84 blade implants. During this period only four bicortical screws and one blade implant failed. The primary and secondary surgical success rate was therefore above 98%, while the prosthetic success rate was 100%. （Bridges which had to be re-fabricated due to implant failure were not taken into account.） Conclusion This approach is recommended as a highly successful and affordable option for a wide range of patients.
基金A substantial part of the work described in this article was supported by the research Contracts 806/31.4830 and 806/31.5511 between the private company Laboratorio Ortoplus S.L.and the University of Málaga,which is acknowledgedwith gratefulness.
文摘Mandibular advancement devices(MADs)are one of the treatments used for Obstructive sleep apnea(OSA).MADs try to maintain the mandible in an advanced position to keep the upper airways open when sleeping.To achieve this goal,most current MADs limit the mouth opening to a few millimetres.The study of the kinematic behaviour of the patient’s jaw is essential in order to design devices that allow greater aperture ranges.For this purpose,a 3D multibody model that reproduces jaw movement has been developed in this work.To this end,the movement of the lower incisor has been determined by means of a vision system and reflective markers.In addition,the kinematics of the temporomandibular joint has been modelled.Next,the device is designed and printed using a cam-follower mechanism.This way,the cam profiles and the followers are optimally designed and positioned for each patient depending on the physiognomy of the jaw and the opening and advancing movement prescribed by the specialist.
文摘Ameloblastoma is a benign but locally aggressive odontogenic neoplasm that accounts for 10% of all tumors arising in the mandible and maxilla (1). Eighty percent of ameloblastomas arise in the mandible, and they are usually found in young adults. It frequently recurs if not adequately
文摘This study presents a reliable method for the semi-automatic generation of an FE model, which determines both geometrical data and bone properties from patient CT scans.3D FE analysis is one of the best approaches to predict the stress and strain distribution in complex bone structures, but its accuracy strongly depends on the precision of input information. In geometric reconstruction, various methods of image processing, geometric modeling and finite element analysis are combined and extended. Emphasis is given to the assignment of the material properties based on the density values computed from CT data. Through this technique, the model with high geometric and material similarities were generated in an easy way. Consequently, the patient-specific FE model from mandible CT data is realized also.
文摘Mesenchymal stromal cells(MSCs)are cells with the characteristic ability of self-renewal along with the ability to exhibit multilineage differentiation.Bone marrow(BM)is the first tissue in which MSCs were identified and BM-MSCs are most commonly used among various MSCs in clinical settings.MSCs can stimulate and promote osseous regeneration.Due to the difference in the development of long bones and craniofacial bones,the mandibular-derived MSCs(M-MSCs)have distinct differentiation characteristics as compared to that of long bones.Both mandibular and long bone-derived MSCs are positive for MSC-associated markers such as CD-73,-105,and-106,stage-specific embryonic antigen 4 and Octamer-4,and negative for hematopoietic markers such as CD-14.
文摘This report,"Mandible exosomal ssc-mir-133b regulates tooth development in miniature swine via endogenous apoptosis" by Li et al. is an important step forward in describing the factors that control tooth development in a large animal model. That many of the regulatory miRNA pathways have been elucidated in murine species have always begged the question as to how relevant they
文摘Spindle cell carcinoma is a rare highly malignant squamous cell carcinoma.Here,we describe a case of a 74-yearold Chinese female who presented with a 2-week history of pain and swelling in the left retromolar region.Surgical resection and titanium plate prosthesis were performed and histological analysis revealed spindle squamous cell carcinoma.
文摘The present author made comparisons between the mandibular fragment and teeth attached on it from longgupo,Wushan on one side,and the corresponding specimens of early \%Homo\% of East Africa,\%Homo erectus\% from Dmanisi and \%Lufengpithecus \% from Yuanmou on other side.The results showed that the size of Wushan specimens are much smaller than those of early \%Homo\% of East Africa and Dmanisi mandible,and are concordant with that of \%Lufengpithecus \%from Yuanmou.Most of the characters which have been used to attribute Wushan mandible to \%Homo \%by some scholars,are shared by both hominid and ape. Among these characters,bifurcation of the root of the premolar is one of the characters of \%Lufengpithecus\% and seldom seen in hominid.The position of the anterior contact facet and the ratio of the length of talonid to that of the crown of Wushan premolar are characteristic in ape.Among the ape fossils avaliable in China \%Lufengpithecus \% is the closest relative of Wushan ape.Whether they have ancestor\|descendant relation is waiting for more findings to prove.
文摘<b><span style="font-family:Verdana;">Background</span></b><span style="font-family:Verdana;">: Tuberculosis is a granulomatous infectious disease which is still being a real health problem in developing countries. Mainly, this specific infection affects pulmonary sites, but, the occurrence in extra-pulmonary sites is more and more reported. However, when extra-pulmonary tuberculosis af</span><span style="font-family:Verdana;">fects the cervico-facial region, the cervical lymph nodes are the most in</span><span style="font-family:Verdana;"><span style="font-family:Verdana;">volved. </span><b></b></span><b><b><span style="font-family:Verdana;">Aim</span></b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> Throughout this case report, we put emphasis on keeping in mind of the possible tuberculous infection in a chronic lesion of mandible in children. </span><b><b><span style="font-family:Verdana;">Case presentation</span></b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> In this article, we present a case of a 2-year-old child who was complaining of swelling of the right angle of the mandible. The com</span><span style="font-family:Verdana;">puted tomography showed an osteolytic lesion suggesting tuberculous os</span><span style="font-family:Verdana;">teomyelitis but didn’t rule out a bony malignant neoplasm of the mandible. The histological examination of biopsy of the lesion proved the tuberculous osteomye</span><span style="font-family:Verdana;">litis of the mandible. The child has received anti-tubercular therapy for 9</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"> months, and she marked a good recovery. </span><b></b></span><b><b><span style="font-family:Verdana;">Conclusion</span></b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> In children, tuberculous osteomyelitis of the mandible is a curable disease without sequel when diagnosis is given at the right time.</span>
基金Supported by Sanming Project of Medicine in Shenzhen,No.SZSM202111012Shenzhen Fund for Guangdong Provincial High-level Clinical Key Specialties,No.SZGSP008Shenzhen Clinical Research Center for Oral Diseases,No.20210617170745001.
文摘BACKGROUND Neurofibromas are benign tumors of a neurogenic origin.If these tumors occur without any other signs of neurofibromatosis,they are classified as isolated neurofibromas.Neurofibromas in the oral cavity mostly occur within soft tissues,indicating that solitary intraosseous neurofibromas in the mandible are rare.Due to the absence of specific clinical manifestations,early diagnosis and treatment of these tumors are difficult to achieve.CASE SUMMARY A 37-year-old female patient visited our hospital due to numbness and swelling of the gums in the right lower molar area that had persisted for half a month.The patient’s overall condition and intraoral examination revealed no significant abnormalities.She was initially diagnosed with a cystic lesion in the right mandible.However,after a more thorough examination,the final pathological diagnosis was confirmed to be neurofibroma.Complete tumor resection and partial removal of the right inferior alveolar nerve were performed.As of writing this report,there have been no signs of tumor recurrence for nine months following the surgery.CONCLUSION This case report discusses the key features that are useful for differentiating solitary intraosseous neurofibromas from other cystic lesions.
文摘Background: In forensic science the identification of a human is based on three important factors: Age, Sex and Stature. Bones are an important tool for it and among human bones the pelvis and the skull are the most reliable source for sex determination. In the absence of complete pelvis, mandi-ble becomes the important source for sex determination since mandible is the most durable and movable part of skull that can resist postmortem changes. The present study is conducted to assess the accuracy and role of few metric and morphological parameters in determination of the sex of dry adult human mandible of North Indian origin. Material & Methods: The Study is conducted on 50 dry intact human adult mandibles of North Indian origin. The metric parameters i.e. bigonial breadth, bicondylar breadth are measured with a Vernier Calliper by two observers. Non-metric parameters being observed are the morphological features like gonion flaring, muscular markings and shape of angle of symphysis menti. Result & Conclusion: It is concluded that bigonial breadth and bicondylar breadth exhibit the sexual dimorphism. Morphological Parameters: Gonion flaring, muscular markings and shape of angle of symphysis menti also demonstrate the sexual dimorphism. These parameters taken together may determine the sex of adult human mandibles. The present study shows that the mandible is an important tool in the determination of gender with high accuracy.
文摘Progressive bone marrow failure and development of malignancies, particularly acute myeloid leukemia and solid tumors the most important features of Fan- coni’s Anemia (FA). This paper reports the case of a 16-year-old patient with FA who developped squa- mous cell carcinoma of the mandible, ten years after the bone marrow transplantation (BMT).
