Effect of estrogen on bone resorption and inflammation in the temporomandibular joint cellular elements

Several epidemiological studies have reported that temporomandibular disorder is more prevalent in women, which suggests the involvement of sex hormones, such as estrogen, in the pathogenesis of this disease. PCR amplification and Western blotting were employed to target the expression of estrogen receptors (ERs) in human fibroblast-like synovial and ATDC5 cells. The effect of estrogen was investigated through the expression of RANKL, osteoprotegerin (OPG), M-CSF/CSF-1 and c-fms. We showed expression of M-CSF/ CSF-1 and c-fms, with time-dependent increase in both after the addition of estrogen. Based on previous studies reporting that M-CSF/CSF-1 regulates the proliferation and differentiation of hemopoietic progenitor cells into mature macrophages, we put forward a new hypothesis based on the increased inflammation and tendency of females to suffer more from temporomandibular disorder (TMD) in the presence of external exacerbating factors. Detection of RANKL and OPG in ATDC5 and expression of both in HFLS was confirmed with complete disappearance of the RANKL band, and marked increase in the expression of OPG after 1 h from the addition of estrogen.     

Skeletal pattern in subjects with temporomandibular joint disorders

Introduction

To establish the skeletal pattern in subjects with malocclusions and temporomandibular disorders (TMD); to assess the relationship between craniofacial skeletal structures and TMD in subjects with malocclusions.

Material and methods

Sixty-four subjects with malocclusions, over 18 years of age, were included in the study. Temporomandibular disorders were clinically assessed according to the Helkimo Anamnestic Index. Subjects underwent a lateral cephalogram. Subjects were grouped according to the sagittal skeletal pattern (ANB angle) into class I, II and III. Parametric Student tests with equal or unequal variations were used (variations were previously tested with Levene test).

Results

Twenty-four patients with TMD (experimental sample); 40 patients without TMD (control group); interincisal angle was higher in class I and II (p < 0.05) experimental subjects; overjet was larger in experimental subjects; midline shift and Wits appraisal were broader in the experimental group in all three classes. In class III subjects, the SNB angle was higher in the experimental group (p = 0.01). Joint noises followed by reduced mandible mobility, muscular pain and temporomandibular joint (TMJ) pain were the most frequent symptoms in subjects with TMD and malocclusions.

Conclusions

Temporomandibular joint status is an important factor to consider when planning orthodontic treatment in patients with severe malocclusions; midline shift, large overjet and deep overbite have been associated with signs and symptoms of TMD.     

Cytopathologic diagnosis on joint lavage fluid for patients with temporomandibular joint disorders

Temporomandibular joint (TMJ) disorders (TMD) are usually diagnosed based on the patient's clinical findings and the results of image investigations; however, understanding of the inflammatory process in TMJ is difficult. In addition, many of the TMJ disease types share common principal symptoms. Therefore, TMJ diseases in the early stage can be misdiagnosed with TMD. It is hypothesized that cytopathologic examination of the joint lavage fluids is useful in interpreting the TMD‐associated inflammatory process from a cellular aspect. The aim of this study was to assess the TMJ lavage fluid cytopathologically in TMD patients. Thirty‐nine patients, clinically diagnosed as TMD, were included in the present study. Clinical symptoms of the patients were recorded. Forty‐four samples of TMJ lavage fluid were collected and paraffin‐embedded cell sections were made by cell block tissue array method. Cytologic conditions in upper articular cavity of TMJ were cytopathologically diagnosed and were compared with the clinical symptoms of each patient. Cell components were detected in 22 of the 44 analyzed joint lavage fluids. There was a correlation between cytopathologic findings and clinical symptoms. Variety of cytopathology and inflammatory conditions in patients with similar clinical symptoms were also found. The results suggested that cytopathologic examination of the joint lavage fluids from TMD patients is helpful for gaining an understanding of the inner local conditions of TMJ at the cellular level. Diagn. Cytopathol. 2014;42:30–36. © 2013 Wiley Periodicals, Inc.     

Subchondral bone changes and chondrogenic capacity of progenitor cells from subchondral bone in the collagenase-induced temporomandibular joints osteoarthritis rabbit model

Purpose: The goals of this study were to characterize subchondral bone changes, and to determine biological activity characteristics of progenitor cell populations from subchondral bone in the collagenase-induced temporomandibular joint osteoarthritis (TMJOA) rabbit model. Greater understanding of such pathological changes occurring in TMJOA samples is critical in the future treatment modalities regarding cartilage protection and repair. Furthermore, the use of progenitor cell populations in various cartilage regeneration strategies proves to be a fruitful avenue for research and clinical applications. Materials and methods: Bone remodeling and anabolic activity of subchondral bone was evaluated by hematoxylin-eosin (H&E), Alcian blue-periodic acid-Schiff (AB-PAS) staining and immuohistochemical staining. The biological activity characteristics of progenitor cells were assessed by expressions of collagen type II, CD44, SOX-9 and MMP-9 by immunohistochemistry and Western blot analysis. Results: In most of the specimens, cartilage of the digested area displayed a reaction characterized by thickening of the cartilage cellular structure with retraction structure formation in the subchondral bone. Most of the specimens focuses on chondroid metaplasia were observed in the subchondral bone, promoting its remodeling, which could develop to endochondral ossification and increasing subchondral bone size. Meanwhile, immunohistochemistry analysis revealed that CD44 expressions in subchondral bone were most significantly increased in TMJOA at 2 weeks group (P < 0.01). And, at 4, 6 and 8 weeks groups, the osteochondral junction had completely disappeared by active subchondral bone remodeling, and collagen type II, CD44, SOX-9 and MMP-9 expressions in active subchondral bone region were significantly increased in TMJOA (P < 0.05). In addition, western blot analysis revealed that CD44 expression significantly emerged in subchondral bone region at 2 weeks group (P < 0.01). Meanwhile, SOX-9 expression emerged in all group, and the intensity was increased in the experimental groups (P < 0.05). Conclusion: Our results suggest that the beneficial activation of progenitor cells and bone marrow stem cells in subchondral bone at early stage of TMJOA played an important role on renovation and remodeling of subchondral bone.     

稳定咬合板治疗颞下颌关节紊乱病的临床疗效观察

目的:探讨佩戴稳定咬合板治疗颞下颌关节紊乱病（TMD）的临床疗效。方法:前瞻性研究。纳入甘肃医学院附属医院口腔科2018年6月—2020年2月收治的TMD患者84例,其中男9例、女75例,年龄16~70（29.5±12.0）岁,均佩戴稳定型咬合板治疗3个月。分别于治疗前和治疗后1周及1、2、3个月共5个时间点,对比患者...     

人工关节磨损钛微粒诱导破骨的RANK∕OPG通路机制的实验研究

目的分析人工关节磨损钛微粒诱导溶骨的RANK/OPG通路机制。方法巨噬细胞分别与清洁钛微粒、细菌内毒素结合钛微粒和细菌内毒素联合培养,作为清洁钛微粒组、细菌内毒素结合钛微粒组及细菌内毒素组,与单纯巨噬细胞组作为对照。每组分别在培养4,8,16,32h各时点取巨噬细胞,分别用反转录聚合酶链反应技术,分别检测核激活因子受体RANKmRNA、骨保护素OPGmRNA表达。结果与对照组比较,清洁钛微粒组和细菌内毒素结合钛微粒组巨噬细胞培养4h时RNKmRNA表达开始增加,之后逐渐升高（〈0.01）;培养8h时骨保护素OP-GmRNA表达轻度增高,随后恢复到对照组水平。细菌内毒素组未检测到核激活因子受体RANKmRNA表达,培养4h时骨保护素mRNA表达轻度一过性增加。结论清洁钛微粒可能通过刺激巨噬细胞过量表达RANK,传导破骨信号,而细菌内毒素并不参与RANK/OPG信号途径诱导溶骨。     

颞下颌关节周边骨性结构关系的观测

目的 研究颞下颌关节周边骨性结构的关系,为关节及颅底手术提供解剖学参考.方法 选取完整清晰的成人颅骨56个,由一名专业的口腔医学教师确定各解剖结构的位置并标号,用游标卡尺、圆规、直尺和量角器测量颅底和颞下颌关节周围重要骨性结构的距离与角度.结果 关节结节最低点至棘孔最外侧点、茎乳孔最前点、卵圆孔最外侧点、颈动脉管外口最...     

Microscopic-anatomic changes of the temporomandibular joint structure in miniature swine due to unilateral occlusion disorders

The influence of artificial unilateral occlusal disturbances on the structure of the temporomandibular joint (TMJ) condyle cartilage was investigated by an experimental study using the miniature pig "MINI-LEWE". After a burden over 20 weeks the side exposed to occlusal disturbance (right TMJ) turned out to have unchanged histological proportions in comparison with control animals. The condyles of the side with pressure loading (left TMJ) exhibited but a changed histological picture. Cartilage resorptions as well as accumulations of large blown chondrocytes indicate an increased tissue reaction within the chondroblastic layer near spongiosa. The morphometric investigations confirm these results. A significant increase was observed in cell density within the chondroblastic layer of the most superior point of the left condylus due to the permanent disturbance of the normal masticatory function.     

The redox states of serum and synovial fluid of patients with temporomandibular joint disorders

The redox states of albumin in serum and synovial fluid (SF) were analyzed in 35 female patients with temporomandibular joint disorders and 9 asymptomatic female healthy volunteers by high-performance liquid chromatographic (HPLC) analysis. Human serum albumin (HSA) is divided by HPLC analysis into three fractions: mercaptalbumin (HMA, reduced form) and nonmercaptalbumin (HNA-1 and HNA-2, oxidized forms). It was found that the characterized values of albumin in SF of patients with the disorders were the fraction of HMA (f (HMA), 65.8 +/- 9.1%), the fraction of HNA-1 (f (HNA-1), 31.3 +/- 8.8%), and the fraction of HNA-2 (f (HNA-2), 2.9 +/- 0.9%), respectively, and similarly the values of albumin in serum of same subjects were f (HMA), 79.4 +/- 4.0%; f (HNA-1), 18.7 +/- 3.8%; and f (HNA-2), 1.9 +/- 0.5%. The HNA fractions in SF were significantly higher than those in serum (p < 0.0001). The SF of patients and even control showed more oxidative condition compared with sera of the same subjects. Each fraction of SF showed significant difference in control (p < 0.05), and greater significance in patients (p < 0.0001). Furthermore, the HNA-2 fraction (f (HNA-2), 2.9 +/- 0.9%) in SF of the patients with temporomandibular joint disorders revealed a significantly higher value (p < 0.01) than that (f (HNA-2), 1.7 +/- 0.3%) of controls. These findings suggested that SF of the temporomandibular joint is more locally oxidized than serum; thus oxidative factors are concerned in the pathogenesis of the temporomandibular joint disorders. It was also suggested that synovial albumin may play a scavenging role against the intraarticular oxidative stress.     

Electromyographical analysis of the masseter muscle in dentulous and partially toothless patients with temporomandibular joint disorders

This study had as objective to analyze with computerized electromyography the masseter muscles bilaterally in twenty individuals with temporomandibular joint dysfunction (DTM), being: the group I consisting of ten individuals with complete dentition and group II constituted by ten individuals with posterior dental absences; comparing nine clinical activities: rest before and after exercises, maximum habitual intercuspation (MIH), right and left laterality, forced centric occlusion, protrusion, bilateral molar bite and chewing. It was utilized the Electromyography K6I-Myotronics, with eight canals and surface silver electrodes. By means of the results analysis, we verified significant differences between the groups (p < 0.01), being group I, presented greater electromyographic activity (32.98 microvolts), than the group II (22.31 microvolts), suggesting that this individuals presented low muscular activity. The interaction between the groups and the clinical activities was significant (p < 0.01), as well as between the groups, clinical activities and muscles (p < 0.05). To clarify which amongst the relative averages the clinical activities were different, calculated the critical value of Tukey, being that rest before and after exercises, MIH, right and left laterality, presented averages with similar distributions, with values below of the values of Tukey, as well as forced centric occlusion, protrusion, bilateral molar bite and chewing presented higher values than Tukey. Based on this research's data, we concluded that the electromyographical analysis of the masseter muscles in Individuals with TMD, dentulous and with dental absence showed that individuals with TMD, dentulous or not, presented elevated muscular activity in rest position and individuals with TMD, dentulous, presented higher electromyographical activity than the individuals with TMD and lacking posterior teeth.     

Development of the human temporomandibular joint

A great deal of research has been published on the development of the human temporomandibular joint (TMJ). However, there is some discordance about its morphological timing. The most controversial aspects concern the moment of the initial organization of the condyle and the squamous part of the temporal bone, the articular disc and capsule and also the cavitation and onset of condylar chondrogenesis. Serial sections of 70 human specimens between weeks 7 and 17 of development were studied by optical microscopy (25 embryos and 45 fetuses). All specimens were obtained from collections of the Institute of Embryology of the Complutense University of Madrid and the Department of Morphological Sciences of the University of Granada. Three phases in the development of the TMJ were identified. The first is the blastematic stage (weeks 7–8 of development), which corresponds with the onset of the organization of the condyle and the articular disc and capsule. During week 8 intramembranous ossification of the temporal squamous bone begins. The second stage is the cavitation stage (weeks 9–11 of development), corresponding to the initial formation of the inferior joint cavity (week 9) and the start condylar chondrogenesis. Week 11 marks the initiation of organization of the superior joint cavity. And the third stage is the maturation stage (after week 12 of development). This work establishes three phases in TMJ development: 1) the blastematic stage (weeks 7–8 of development); 2) the cavitation stage (weeks 9–11 of development); and 3) the maturation stage (after week 12 of development). This study identifies the critical period of TMJ morphogenesis as occurring between weeks 7 and 11 of development. Anat Rec 255:20–33, 1999. © 1999 Wiley‐Liss, Inc.     

Functional anatomy of the temporomandibular joint

Summary A study of 72 temporomandibular joints of adults without any gross signs of degenerative changes was made, in order to analyse the stress on individual regions of the joint, and to determine the path of the split line pattern in the articular cartilage. The cancellous architecture and the material distribution in the juxta-articular bone were also investigated. Zones of high-density compact substance in the lateral region of the joint, and the presence of attractive singular points in the split line orientation in this localization, suggest great stress on the lateral part of the temporomandibular joint. This increased stress in the lateral region is confirmed by the fact that arthrotic changes in the temporomandibular joint first almost always appear laterally. Degenerative changes usually originate at the articular disc, affect the articular tubercle after a delay, and finally spread to the condyle. Besides the greater physiological, mechanical stress on the lateral region of the joint, the force acting on every individual temporomandibular joint is influenced by the dental condition. The molars and bicuspids serving as a support zone play a decisive role in this context.Dedicated to Professor Dr. H. Haug on the occasion of his 70th birthday     

Multinucleation enhances macrophage-mediated bone resorption

The degradation of mineralized connective tissues in vivo is a function of multinucleated giant cells ('clasts) derived from and belonging to the mononuclear phagocyte family. However, it is not known whether the attainment of the multinucleated state is causally or only coincidentally related to 'clast degradative activity. To address this issue, 'clast-like polykaryons were produced by exposing elicited rat macrophages to human serum (10% for 7 to 14 days). Pure populations (90%) of multinucleated cells and their mononuclear macrophage counterparts were then assessed for their ability to bind and degrade 45Ca-labeled, devitalized bone particles in vitro. Macrophage polykaryons bind bone particles significantly more effectively than ordinary elicited mononuclear macrophages (approximately 40% attachment versus approximately 25%; p less than 0.001). Similarly, 'clast-like polykaryons resorb both large (24 to 43 microns diameter) and small (less than or equal to 24 microns) particles more efficiently than age- and culture condition-matched mononuclear cells (treated to control ratios, 1.3 to 4.2:1, p less than 0.001). This difference in degradative activity remains highly significant whether resorption (45Ca release) is expressed per microgram of DNA, per 100 micrograms of protein, or per total cell surface area. We conclude that multinucleation produces qualitative changes in the resorptive capacity of macrophagic cells. The data suggest that the formation of polykaryons is a physiologically important event in 'clast development.