Idiopathic osteosclerosis mimicry of a tooth: case report

This report presents two cases of idiopathic osteosclerosis involving the maxilla and mandible which were identified as a buccally impacted canine and a retained root, respectively, on clinical and plain radiographical examinations. Both patients were females who presented with hypodontia. Radiographic evaluation revealed solitary well-defined radiopaque masses with thickened cortical border. Both patients were undergoing orthodontic treatment and one was planned for a surgical traction of unerupted tooth prior to cone-beam CT assessment. In this report, we reviewed the clinical findings and explained the radiographic appearance of idiopathic osteosclerosis through plain radiographs and cone-beam CT to facilitate its identification among general dentists and oral and maxillofacial radiologists.     

Histological evaluation of a tooth with hyperplastic pulpitis and periapical osteosclerosis

Histological examination was carried out in a case of hyperplastic pulpitis associated with periapical osteosclerosis.     

Idiopathic osteosclerosis of the jaws followed through a period of 20-27 years

AIM: The aim of the present study was to examine the prevalence of idiopathic osteosclerosis (IO) in a baseline sample and to follow the patients through an extended period of time. METHODOLOGY: The sample consisted of 210 patients treated in a dental school and having a complete series of intraoral radiographs at the time of treatment and at a follow-up 10-17 years later. A further 10 years later, 130 patients had another follow-up. RESULTS: Sixteen of the 210 patients were found to have IO, mostly in the mandibular molar and premolar regions. Fourteen had one lesion, one had two lesions and one had three lesions. The mean age of these patients was 47 years as compared to 44 years for the rest of the patient group. No sex predilection was found. At the first follow-up, one lesion had disappeared, one had reduced in size and one new lesion appeared. At the second follow-up, eight patients with IO could be re-examined. Two lesions, unchanged at the first follow-up, had reduced in size and two new lesions appeared. In the area of the new lesions, residual roots were observed in the earlier radiographs. CONCLUSION: Our findings support the theory that IO lesions should be considered anatomical variants. In some cases, however, a local aetiological agent may cause development of structures with an identical appearance.     

Bilateral asymmetry of tooth formation is elevated in children with simple hypodontia

Objective

Tooth formation normally progresses symmetrically between sides; the goal in this study was to test the clinical impression that left–right asymmetry in tooth formation is elevated in children with simple hypodontia.

Materials and methods

Data from panoramic X-rays of American white children (5–14 years of age) with simple hypodontia (n = 158) were compared to a comparable group from the same practises with all teeth present (n = 206). Children with hypodontia were otherwise phenotypically normal, with no cleft or recognized syndrome. Crown–root formation of each tooth (ignoring third molars) was scored using an 11-grade scheme. Analysis relied on chi-square goodness-of-fit tests and odds ratios.

Results

Hypodontia typically occurs unilaterally; it is more common in girls than boys; and it most frequently affects second premolars (omitting third molars). No evidence of a side preference was found as regards absence of the tooth or tooth formation. Tooth formation was decidedly more frequently asymmetric in those with hypodontia, though again the distribution by side was random in the sample. Summed over all tooth types, asymmetric formation occurred in 18.6% of cases with hypodontia compared to 11.9% in controls, and this is significant by chi-square (P = 0.03), with an odds ratio of 1.43 (CL: 1.02, 2.04). All tooth types exhibit elevated developmental asymmetry in the hypodontic sample despite only one or a few teeth being agenic.

Conclusions

Increased asymmetry suggests a breakdown in the rigour of developmental timing in cases with simple hypodontia. In concert with increased frequencies of other growth issues in such cases, such as side differences in size and morphology, hypodontia is best viewed as a symptom of an anatomically broad relaxation of developmental canalization between homologous structures, not an isolated dental feature.     

Radiographic study of periosteal new bone formation in osteomyelitis of the mandible

A total of 1008 cases with osteomyelitis of the mandible underwent radiological examinations at the department of Oral Radiology, Osaka Dental University Hospital from 1979 to 1988. Osteomyelitis with periosteal new bone formation was observed in 114 out of the 1008 cases (11.3%). The radiographic patterns of the periosteal new bone formation were grouped into 3 types: solid, laminated and one-layer. Sixty-seven of the 114 cases (58.8%) were of the solid type, 23 cases (20.2%) were the laminated type and 24 cases (21.0%) were the one-layer type. The average age in the solid type was 30.8 years, 23.8 years in the laminated type and 38.0 years in the one-layer type. Concerning the sites of periosteal new bone formation 94 out of 114 cases (82.5%) were in the mandibular body and 20 (17.5%) in the ascending ramus of the mandible. The extent of the periosteal new bone formation was far larger among the young. This was particularly remarkable in the ascending ramus of the mandible. These findings were proved to correlate with the age, the clinical symptoms, the route of infection and the condition of eruption in the lower molars.     

Characteristics of iatrogenic mandibular fractures associated with tooth removal: review and analysis of 189 cases

Fracture of the mandible during exodontia is fortunately rare, but is under-reported. A review identified 189 documented cases of iatrogenic fractures of the mandible (IFM) associated with the removal of teeth. The reasons for its occurrence are thought to be multifactorial and include age, sex, degree of tooth impaction, relative volume of the tooth in the jaw, pre-existing infection or bony lesions, failure to maintain a soft diet in the early postoperative period, and the surgical technique. The clinical experience of the surgeon does not seem to have an important role. We review the aetiology of iatrogenic mandibular fracture and summarise the ways of minimising this complication.     

Melnick-Needles syndrome associated molecule,Filamin-A regulates dental epithelial cell migration and root formation

BackgroundFilamin-A (FLNA) is one of the adaptor proteins binding to both integrin beta chain and actin filament. Several kind of mutation in human FLNA gene were observed in Melnick-Needles syndrome (MNS). However, the role of FLNA in tooth formation is still unknown.Matrials and methodsWe analyzed the tissue expression of FLNA during tooth development using immunostaining. The role of FLNA in cell migration was analyzed using a scratch assay. In addition, we analyzed the phenotype of teeth in patients with Mernick-Needles syndrome caused by FLNA gene abnormalities.ResultsFLNA expressed in inner and outer enamel epithelium in mouse tooth germ and also expressed in cervical region of dental epithelium. In postnatal stage, FLNA expressed in ameloblast and odontoblast layers. In rat dental epithelium cell line SF2, FLNA is localized at the boundary between cells and co-localized with the terminal region of F-actin filament. shRNA-FLNA transfected cells showed delayed cell migration and scratch closure compared with control cells. Analysis of actin fiber movement by time-lapse confocal microscopy showed slower fiber movement in shRNA-FLNA over expressing SF2 cells. Novel mutation in FLNA gene was observed in MNS with tooth anormaly. This patient showed tooth agenesis and short root in both primary and permanent dentition with thin enamel.ConclusionTaken together, these results suggest that filamin-A is play a key role for dental epithelium migration and root formation.     

Clinical study on prognostic factors for autotransplantation of teeth with complete root formation

Autotransplantation is often performed to replace a missing tooth, but tooth autotransplantation has been reported in fewer teeth with complete root formation than those with incomplete root formation. The aim of this prospective study was to evaluate the factors that affect the prognosis of autotransplantation of teeth with complete root formation. 109 patients with 117 transplants were studied. Of the 117 transplants investigated, 14 (12%) failed during the observation period. The overall 1-year survival rate was 96%; the 5-year survival rate was 84%. The major causes of failure were unsuccessful initial healing and replacement root resorption with periodontal inflammation. Factors significantly associated with unsuccessful transplantation, in single factor analysis, were age 40 years or more, molar tooth as donor, probing pocket depth to 4 mm or more, history of root canal treatment, multi-rooted teeth and fixation with sutures. Pocket depth of 4 mm or more and history of root canal treatment appeared to increase the risk of unsuccessful transplantation in multivariate analysis. It is suggested that the pocket depth of the donor tooth and history of root canal treatment are related to the healing of paratransplantal tissue and root resorption.     

上皮根鞘结构对牙根发育的影响

目的: 研究上皮根鞘的结构对牙根发育的影响。方法: 选择出生后(postnatal, PN)8 d的SD大鼠, 切取第一磨牙牙胚的颈部组织, 用胶原酶和dispase酶消化, 1组直接离心形成细胞团, 另1组加用胰酶消化后, 离心形成细胞团。将细胞团体外培养4 h后, 种植到母鼠肾被膜下, 4周后取材观察。结果: 胶原酶和dispase酶消化可将上皮根鞘解离成碎片, 加用胰酶消化后, 上皮根鞘被解离为单个细胞。含有上皮根鞘碎片的细胞团种植后形成牙根样结构, 而含有上皮根鞘离散细胞的细胞团则形成管状牙本质和骨样牙本质块。结论: 上皮根鞘的结构对其引导牙根发育具有重要作用。     

Influence of age on tooth autotransplantation with complete root formation

The aim of this study was to investigate risk factors with age in the long‐term prognosis of autotransplantation of teeth with complete root formation at dental clinics. Participating dentists were asked to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. The data were screened to exclude patients who were under 25 or 70 years of age and over, those who were smokers or whose smoking habits were unknown, those whose transplanted teeth had incomplete root formation or multiple roots and those with fewer than 25 present teeth post‐operation. The participants in this study were 71 men (74 teeth) and 100 women (107 teeth) ranging from 25 to 69 years of age. Third molars were used as donor teeth in 89·0% of the cases. The participants were divided into three age groups of 25–39, 40–54 and 55–69. Survival analysis was conducted using the Kaplan–Meier method, and a log‐rank test revealed that there were no significant differences in age groups for men or women. Cox regression analysis indicated that the survival of transplanted teeth was not influenced by age. However, although not statistically significant, the clinical success rate was lower in the 55–69‐year‐old group than that in the younger groups. These results indicate that if suitable donor teeth are available and the conditions are right, autotransplantation is a viable treatment for missing teeth regardless of the age of the patient.     

骨性下颌前突伴偏斜畸形的牙弓和牙齿代偿分析

目的：作者对骨性下颌前突伴偏斜患者的牙弓和牙齿代偿现象进行研究。方法：测量11例骨性下颌前突伴偏斜患者治疗前模型，将上颌腭中缝作为中线标准，测量牙弓两侧同名牙接触点到腭中缝的距离，观测牙弓的对称性。同时He平面作为参考平面，测量上下颌后牙颊舌向倾斜程度。结果：骨性下颌前突伴偏斜患者的上牙弓左右不对称,偏斜侧（下颌颏部所指向的一侧）牙弓宽度明显大于对侧。偏斜侧上后牙颊向倾斜， ．下后牙舌向倾斜。结论：下颌前突伴偏斜形会导致上颌牙弓和上下颌后牙出现代偿，在术前矫治的重点是去代偿治疗。     

Effects of antiresorptive medications on tooth root formation and tooth eruption in paediatric patients

Tooth eruption is a pivotal milestone for children's growth and development. This process involves with the formation of the tooth root, the periodontal ligament (PDL) and the alveolar bone, as the tooth crown penetrates the bone and gingiva to enter the oral cavity. This review aims to outline current knowledge of the adverse dental effects of antiresorptive medications. Recently, paediatric indications for antiresorptive medications, such as bisphosphonates (BPs), have emerged, and these agents are increasingly used in children and adolescents to cure pathological bone resorption associated with bone diseases and cancers. Since tooth eruption is accompanied by osteoclastic bone resorption, it is expected that the administration of antiresorptive medications during this period affects tooth development. Indeed, several articles studying human patient cohorts and animal models report the dental defects associated with the use of these antiresorptive medications. This review shows the summary of the possible factors related to tooth eruption and introduces the future research direction to understand the mechanisms underlying the dental defects caused by antiresorptive medications.     

17例牙根发育完成的自体恒牙移植的回顾性分析

目的:对牙根发育完成的17例自体牙移植病例进行回顾性分析,评估其5年存留率和成功率.方法:纳入近5年行自体牙移植治疗且随访12个月以上的病例17例,术后1个月、3个月、6个月、1年,以后间隔1年复查,行临床及影像学检查.分别从性别、年龄、供牙区颌位及受植区有无根尖炎症评估其预后影响因素,采用Kaplan-Meier法进...     

Fragment reattachment associated with pulpotomy in a posterior tooth with incomplete root formation

This article reports a case of preserving pulp vitality combined with aesthetics and functional reconstruction of an immature permanent molar extensively destroyed because of a carious lesion. After a pulpotomy using calcium hydroxide, the tooth crown was restored by bonding a dental fragment obtained from an extracted tooth from another individual. Aspects of diagnosis and treatment that directly affect the prognosis of the techniques are discussed. Radiographic and clinical follow-up for two years showed complete root development and a very satisfactory restoration with regard to aesthetics and function.     

Overeruption without root exposure of third molars and periodontal health in the mandible

Bone formation is seen around the third molar even when the tooth is exposed to the oral environment due to overeruption. To determine if overeruption of the third molar with or without root exposure is related to the status of the exposure of other teeth in the mandible, using orthopantomographs, 424 third molars were studied in 371 patients who were over 41 years of age. The rate of overeruption and root exposure in third molars was measured, and its relationship to the number of teeth lost and the rate of root exposure in other teeth in the mandible was analyzed. Tooth loss in the group of third molars with overeruption without root exposure was greater than in that without overeruption or root exposure in men, whereas the relationship was not seen in women. We found that root exposures of other teeth in the group of third molars with overeruption without root exposure were significantly smaller than in those with root exposure in both genders. Third molars with overeruption without root exposure, in which bone formation was easy to observe for radiographic diagnosis, were correlated with periodontal health in the mandible, suggesting a component of precision determination for predicting resistance to periodontitis.     

Lithium chloride reduces orthodontically induced root resorption and affects tooth root movement in rats

Objective:To investigate the influence of lithium chloride (LiCl) on orthodontic tooth movement (OTM), orthodontically induced root resorption (OIRR), and bone morphometry.Materials and Methods:Ten-week-old female Sprague Dawley rats (n = 32) were divided into four groups based on the concentration of LiCl administered daily per kilogram body weight: 0 (control group), 0.32, 0.64, and 1.28 mM/kg body weight. The maxillary left first molars were moved mesially by a 10 cN coil spring for 14 days. Micro-computed tomography, scanning electron microscope, and scanning laser microscope images were taken to measure the amount of OTM, the volume of OIRR, and bone morphometry.Results:OIRR clearly decreased depending on the amount of LiCl administered, although OTM moderately decreased. The tooth inclined mesially and the root apex moved distally in the control and 0.32 mM groups. On the other hand, the tooth inclination angle became smaller and the root apex moved mesially in the 0.64 and 1.28 mM groups. In bone morphometry, the cortical bone mineral content and bone volume increased because of LiCl administration, and the trabecular bone measurements decreased. OIRR negatively correlated to the cortical bone measurements, and the amount of OTM significantly correlated to the cortical bone morphometry.Conclusions:In rats, LiCl reduced OIRR, which induced mesial movement of the tooth root apex. OIRR positively correlated to cortical bone morphometry.     

Neurofibromatosis type 1 associated with bilateral central giant cell granuloma of the mandible

Neurofibromatosis type 1, or von Recklinghausen disease, is one of the most common hereditary neurocutaneous disorders in humans. Clinically, Neurofibromatosis type 1 is characterized by café-au-lait spots, freckling, skin neurofibroma, plexiform neurofibroma, bony defects, Lisch nodules and tumors of the central nervous system. Central giant cell granuloma is a benign central lesion of bone, primarily involving the jaws, of variably aggressive nature characterized by aggregates of multinucleated giant cells in a background of cellular vascular fibrous connective tissue and spindle-shaped mononuclear stromal cells. The association between neurofibromatosis and central giant cell granuloma has been reported in the literature. A case of mandibular bilateral central giant cell granuloma in a patient with Neurofibromatosis type 1 was conservatively but successfully treated by adequate surgical curettage of mandibular bone lesions.     

吡咯并喹啉醌对Bmi-1基因敲除小鼠下颌骨及牙发育障碍的治疗作用及机制研究

目的 探讨吡咯并喹啉醌(pyrroloquinoline quinone,PQQ)对Bmi-1基因敲除(Bmi-1knock out,BKO)小鼠的下颌骨及牙发育障碍的治疗作用及其机制.方法 将同窝的Bmi-1+/-雌雄小鼠进行配对,取7周龄正常饮食WT小鼠(10只,WT组),正常饮食BKO小鼠(10只,BKO组),以及正常饮食添加PQQ的BKO小鼠(10只,BKO+PQQ组),利用X线和显微CT、HE染色、组织化学及免疫组织化学、流式细胞仪检测等方法对3组小鼠分别检测下颌骨及牙的大小和骨密度、下颌牙槽骨骨皮质厚度、下颌第一磨牙前期牙本质厚度、下颌骨成骨及破骨细胞数、股骨、胸腺和肝脏的活性氧类水平等指标,并对计量资料结果3组间的总体比较和两两比较分别行单因素方差分析和t检验.结果 WT组小鼠表型正常,BKO+PQQ组小鼠整体表型较BKO组小鼠部分改善、体质量增加、生存期明显延长;X线及显微CT结果均显示BKO+PQQ组小鼠下颌骨及牙的大小和骨密度增加;BKO+PQQ组小鼠下颌牙槽骨骨皮质厚度[(68.65±0.25) μm]与BKO组小鼠[(42.45±0.35) μm]相比差异有统计学意义(P＜0.01);BKO+PQQ组小鼠下颌第一磨牙前期牙本质厚度[(4.25±0.15)μm]与BKO组小鼠[(31.55±0.35) μm]相比差异有统计学意义(P＜0.001);PQQ组小鼠下颌骨成骨细胞数[(38.45±0.25)个/mm3]显著高于BKO组小鼠[(18.15±0.55)个/mm3] (P＜0.01);BKO+PQQ组小鼠下颌骨破骨细胞数[(9.45±0.25)个/mm3]显著低于BKO组小鼠[(14.25±0.35)个/mm3] (P＜0.01);与BKO组小鼠相比,BKO+PQQ组小鼠股骨、胸腺和肝脏的活性氧类水平均显著下降(P＜0.01).结论 PQQ通过促进成骨细胞骨形成、减少破骨细胞骨吸收、清除活性氧类、减少DNA损伤等综合作用发挥对BKO小鼠牙及下颌骨发育障碍的治疗作用.