Three-dimensional evaluation of condylar morphology after orthodontic treatment in adult patients with Class II malocclusion by cone-beam computed tomography.

BACKGROUND: The aim of this study was to evaluate the condylar morphological changes after orthodontic treatment in adult patients with Class II malocclusion using a Cone-beam computed tomography (CBCT). METHODS: Images of twenty-eight adult patients with Class II malocclusion who have no temporomandibular symptoms were involved in this study. To analyze the post-treatment changes in condylar morphology, mimics 17.0 software was used to measure several values and reconstruct the three-dimensional condyle, including height of the condyle, area and bone mineral density of the maximum axial and sagittal section, volume and bone mineral density of the three-dimensional condyle and condylar head before and after orthodontic treatment. Using SPSS 19.0 software package Paired t-test was applied for comparison of condylar morphology analysis between pre-treatment and post-treatment. RESULTS: Height of condylar head increase significant (P < .05). Bone mineral density showed a decrease in the maximum axial and sagittal section, three-dimensional condyle and condylar head (P < .01). Evaluation of volume revealed that volume of both condyle and condylar head decrease considerably (P < .05). No significant difference was detected in other values ((P > .05). CONCLUSION: Condylar volume decreased and height of condylar head have changed, so we speculated that adaptive bone remodeling of the condyle occurs.

Highly Selective Capture of Monophosphopeptides by Two-Dimensional Metal-Organic Framework Nanosheets.

Separation of monophosphopeptides from multi-phosphopeptides in complex biological samples is significant in the study of protein kinase signal transduction pathways. To the best of our knowledge, very few materials have been reported that could selectively enrich monophosphopeptides because of the chemical difficulty in retaining the intermediate monophosphopeptides and excluding both non-phosphopeptides and multi-phosphopeptides in acidic conditions, which requires unique interactions to balance the metallic affinity and the hydrophobicity. With the large surface area, abundant accessible active sites, and ultrathin structures, two-dimensional (2-D) metal-organic framework (MOF) Hf-1,3,5-tris(4-carboxyphenyl)benzene (BTB) nanosheets were rationally selected. Due to the elongated organic ligands and the balance between metallic affinity of clusters and hydrophobicity from ligands, the 2-D Hf-BTB nanosheets exhibited unique enrichment selectivity toward monophosphopeptides. The 2-D MOF nanosheets demonstrated excellent sensitivity (detection limit of 0.4 fmol µL-1) and selectivity [1:1000 molar ratios of ß-casein/BSA (bovine serum albumin)] in model phosphopeptides enrichment. The nanosheets were implemented for the analysis of nonfat milk and human saliva samples as well as in situ isotope labeling for dysregulated phosphopeptides from patients' serum with anal canal inflammation, exhibiting 6.6-fold upregulation of serum phosphopeptide HS4 (ADpSGEGDFLAEGGGVR) compared to the control healthy serum. The proteomics analysis of mouse brain cortical samples associated with Alzheimer's disease, which were from Akt (protein kinase B) conditional knockout mouse and littermate control mouse, was further established with 2-D Hf-BTB nanosheets. With high capture efficiency for monophosphopeptides, this method was capable of distinguishing the difference of monophosphopeptides from microtubule-associated protein τ (MAPT/τ) between the Akt knockout sample and control sample.

Expression of endoplasmic reticulum stress protein in rabbit condyle cartilage following anterior disk displacement.

OBJECTIVE: Anterior disk displacement (ADD) is a most common subtype of temporomandibular disorders (TMD), which is promoted by chondrocytes apoptosis. However, the signaling pathways that trigger apoptosis are still unknown. The aim of this study was to investigate the expression of endoplasmic reticulum (ER) stress-related proteins in the condylar cartilage of rabbits following ADD. METHODS: Sixty healthy adult rabbits were randomly assigned to the experimental and sham-operated control groups (n = 12). The experimental rabbits were subjected to surgical ADD in the right temporomandibular joints. The production of ER stress-related proteins C/EBP homologous protein (CHOP), glucose-regulated protein 78 (GRP78), cleaved caspase-3, and caspase-12 in cartilage was evaluated by immunohistochemistry, quantitative real-time PCR, and Western blot analysis. RESULTS: Our results showed that the expression of CHOP, GRP78, cleaved caspase-3, and caspase-12 increased significantly along with degenerative changes in cartilage after ADD. CONCLUSION: These results indicate that the ER stress pathway is activated in ADD cartilage and might promote the development of TMD.

Role of endoplasmic reticulum stress pathway in hydrostatic pressure-induced apoptosis in rat mandibular condylar chondrocytes.

Excessive mechanical loads induce chondrocyte apoptosis and irreversible cartilage degeneration, but the underlying molecular mechanism is poorly understood. The aim of this study was to investigate the possible role of endoplasmic reticulum (ER) stress pathway in hydrostatic pressure (HP)-induced apoptosis in rat mandibular condylar chondrocytes. Chondrocytes were isolated from rat mandibular condylar cartilage and subjected to HP. Cell viability and apoptosis were assessed by Cell Counting Kit-8 and flow cytometry assay. Expression of ER stress-associated molecules was detected by quantitative real-time PCR and western blot analysis. In addition, expression of apoptosis-related proteins (bax, bcl-2, and cleaved-caspase-3) was assessed by western blot. To explore ER stress function, chondrocytes were pretreated with salubrinal before exposure to HP. Expression of type II collagen, aggrecan, MMP-13, and ADAMTS-5 was evaluated by real-time PCR. The results indicated that HP reduced cell viability in a magnitude- and time-dependent manner. HP-induced activation of ER stress pathway by increasing expression of GRP78, CHOP, caspase-12, PERK, and peIF2α in chondrocytes. Moreover, the expression of bax and cleaved-caspase-3 was increased, while the expression of bcl-2 was decreased in response to HP as the stress time prolonged. In addition, salubrinal suppressed HP-induced apoptosis, upregulated type II collagen and aggrecan mRNA expression, and downregulated MMP-13 and ADAMTS-5 mRNA expression in response to HP. These results demonstrate that HP induces apoptosis in mandibular condylar chondrocytes through ER stress-mediated apoptotic pathway. Suppression of ER stress by salubrinal prevents chondrocytes from undergoing apoptosis and matrix degradation induced by HP.

Low-dose rhBMP2/7 heterodimer to reconstruct peri-implant bone defects: a micro-CT evaluation.

OBJECTIVES: To delineate the dynamic micro-architectures of bone induced by low-dose bone morphogenetic protein (BMP)-2/7 heterodimer in peri-implant bone defects compared to BMP2 and BMP7 homodimer. MATERIAL AND METHODS: Peri-implant bone defects (8 mm in diameter, 4 mm in depth) were created surrounding SLA-treated titanium implants (3.1 mm in diameter, 10 mm in length) in minipig's calvaria. We administrated collagen sponges with adsorbed low-dose (30 ng/mm(3) ) BMP2/7 to treat the defects using BMP2, BMP7 or no BMP as controls.2, 3 and 6 weeks after implantation, we adopted micro-computer tomography to evaluate the micro-architectures of new bone using the following parameters: relative bone volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), connectivity density, and structure mode index (SMI). Bone implant contact (BIC) was also revealed histologically. RESULTS: Consistent with 2 and 3 weeks, after 6 weeks post-operation, BMP2/7 resulted in significantly higher BV/TV (63.033 ± 2.055%) and significantly lower SMI (-4.405 ± 0.500) than BMP2 (BV/TV: 43.133 ± 2.001%; SMI: -0.086 ± 0.041) and BMP7 (BV/TV: 41.467 ± 1.850%; SMI: -0.044 ± 0.016) respectively. Significant differences were also found in Tb.N, Tb.Th and Tb.Sp at all time points. At 2 weeks, BMP2/7 resulted in significantly higher BIC than the controls. CONCLUSIONS: Low-dose BMP2/7 heterodimer facilitated more rapid bone regeneration in better quality in peri-implant bone defects than BMP2 and BMP7 homodimers.

The relationship between partial disc displacement and mandibular dysplasia in female adolescents.

BACKGROUND: The objective of the present study was to investigate the possible relationship between partial disc displacement of the temporomandibular joint (TMJ) and mandibular dysplasia. MATERIAL/METHODS: The TMJ disc position of 46 female adolescents, with Class II, Division 1 malocclusion, aged 10.1 approximately 12.8 years, was quantitatively measured with magnetic resonance imaging (MRI) examinations. Meanwhile, mandibular size and form were determined from cephalometric radiographs. The possible correlation between disc status and mandibular morphology was assessed by means of the Pearson Correlation. In addition, the differences in mandibular size and form between the partial disc displacement group (displaced group) and the disc normal group were also assessed. RESULTS: The results of Pearson Correlation showed that the displaced group had shorter mandibular body length and total mandibular length (Go-Po/Ca-Dm, r=-0.500; Go-Po/ Dp-Cc/Cs-Cc, r=-0.500; Ar-Me/ Ca-Dm, r=-0.459). The patients with horizontal growing style presented more anterior displaced disc (N-S-Gn/ Ca-Dm, r=-0.492). Furthermore, a significantly shorter mandibular body length (Go-Po), a steeper mandibular plane (MP/FH) and a more obtuse mandibular angle (Ar-Go-Me) were found in the displaced group. However, no relationship between the size of the vertical mandible and the disc status was noticed. CONCLUSIONS: Partial disc displacement in Class II, Division 1 cases may be associated with the mandible with horizontal deficits instead of the mandible with vertical deficits.

[Progress and prospect in the research of bone morphogenetic protein heterodimer].

Bone morphogenetic protein (BMP) homodimers are of significant osteoinductivity. However, their clinical application is limited because of high effective dosage. Recently, BMP heterodimers are reported to address the issue. This is a review of the researches on BMP heterodimers, including existent evidences, types and synthetic methods, biological activities in comparison to BMP homodimers and possible mechanisms, further research direction and future expectations.

Inferior alveolar canal course: a radiographic study.

OBJECTIVES: To describe the morphology and course of the inferior alveolar canal (IAC) as it appears in digital panoramic radiographs. MATERIALS AND METHODS: Three hundred and eighty-six digital rotational panoramic radiographs (OPG) were studied using the Clinview Software (6.1.3.7 version, Instrumentarium). Among the 386 radiographs, 86 radiographs with 5-mm steel balls were used to calculate the magnification. RESULTS: The average magnification of radiographs in this study was 7.24+/-7.55%. The course of IAC as seen in the panoramic radiograph may be classified into four types: (1) linear curve, 12.75%, (2) spoon-shaped curve, 29.25%, (3) elliptic-arc curve, 48.5%, and (4) turning curve, 9.5%. On panoramic radiographs, the IAC appeared closest to the inferior border of the mandible in the region of the first molar. In relation to the teeth, on panoramic radiographs, the IAC appeared closest to the distal root tip of the third molar and furthest from the mesial root tip of the first molar. CONCLUSION: In the OPG, there are four types of IAC: linear, spoon shape, elliptic-arc, and turning curve. The data found in the study may be useful for dental implant, mandibule surgery, and dental anesthesia. The limitations of the panoramic radiograph in depicting the true three-dimensional (3D) morphology of the IAC are recognized, computed tomography (CT) and cone beam (CB)3D imaging being more precise.

Time course of expression of bcl-2 and bax in rabbit condylar chondrocytes following forward mandibular positioning.

OBJECTIVE: To clarify the expression of Bcl-2 and Bax following forward mandibular positioning (FMP) in the condylar chondrocytes of rabbits. MATERIALS AND METHODS: Sixty rabbits at 8 weeks of age were randomly allocated to the experimental group (n = 36) and control group (n = 24). Rabbits in the experimental group were induced to FMP by a functional appliance. Six rabbits from the experimental group and four from the control group were sacrificed after 3 days and 1, 2, 4, 8, and 12 weeks, respectively. All the right temporomandibular joints (TMJs) were collected and the expression of Bcl-2 and Bax was evaluated by immunohistochemical staining. RESULTS: The results showed the expression pattern of Bcl-2 and Bax during 12 weeks after FMP. The expression of Bcl-2 reached the highest level at 1 week, whereas Bax reached its maximal expression after 4 weeks. Subsequently, the expression of Bcl-2 and Bax gradually decreased. The ratio of Bcl-2/Bax began to decrease 3 days after FMP and continued to decline until 12 weeks. CONCLUSIONS: FMP with functional appliances could change the expression of Bcl-2 and Bax, which is related to apoptosis in condylar chondrocytes.

Differential expression of apoptosis-associated proteins in chondrocytes of the mandibular condyles of rabbits with anterior disk displacement.

Apoptosis is a potential contributor to anterior disk displacement (ADD) in temporomandibular joint disorders (TMD). The aim of this study was to investigate the expression of key protein regulators involved in apoptosis in the chondrocytes of mandibular condyles with induced ADD in experimental animals. ADD was surgically induced in the left temporomandibular joint (TMJ) of 15 rabbits without opening their bursas. A sham operation was performed on the right TMJ without displacing the disk forward. At the end of one, two, and four weeks after surgery, mandibular condyle samples were collected for protein extraction. The production of apoptosis-associated proteins Fas, capase-8, Bcl-2, and Bax was determined using Western blotting. The results indicate that the production of Fas and caspase-8 increased continuously after ADD. Meanwhile, the level of Bcl-2 decreased, and the production of Bax gradually increased following ADD. These results indicate that alterations in protein production of Fas, caspase-8, and the ratio of Bcl-2 to Bax are consistent with an increase of apoptotic activity in the chondrocytes, which may eventually lead to TMD.

The effect of low-magnitude high-frequency loading on peri-implant bone healing and implant osseointegration in Beagle dogs.

PURPOSE: Low-magnitude, high-frequency (LMHF) loading plays an important role in bone healing. The present study aimed to evaluate the effect of LMHF loading applied directly to titanium dental implants on peri-implant bone healing and implant osseointegration. METHODS: The mandibular premolars and molars were extracted from six male Beagle dogs. Three months post-extraction, each of the six dogs had three titanium implants (Aadva Standard Implant Narrow, Φ3.3×8mm) inserted into the mandibular premolar and molar area (three implants per side). In each animal, one side was randomly selected to undergo daily LMHF loading (treatment group), while the other side had no further intervention (control). The loading was applied directly to the implant abutment using an individual jig and a custom-made loading device (8µm, 100Hz). The implant stability quotient (ISQ) was tested every week. Three dogs were euthanized after 2 weeks, and three were euthanized after 8 weeks. Tissue samples were fixed and stained for micro-computed tomography (micro-CT) and histomorphometric analyses. Data were analyzed statistically, with significance set at p<0.05. RESULTS: The treatment group had significantly increased peri-implant bone volume relative to tissue volume in region of interest 2 (100-500µm) compared with the control group after 2 weeks of loading (p<0.05); however, there was no significant difference between groups after 8 weeks. The ISQ value and the micro-CT results did not differ between groups during the study period. CONCLUSIONS: LMHF loading positively influenced peri-implant bone healing in the early healing period.

A Novel Experimental Dental Implant Permits Quantitative Grading of Surface-Property Effects on Osseointegration.

PURPOSE: To test the hypothesis if a novel single-chamber experimental dental implant allows in vivo the quantitative assessment of osseointegration over time and as a function of different surface properties (physical, chemical, geometric, biologic [osteoconductive or osteoinductive]) in a biologically unfavorable environment (local osteoporosis). MATERIALS AND METHODS: Three prototypes of a novel experimental implant with different chamber sizes (small, medium, and large) were compared with each other to find out the minimum size of bone chambers needed to allow a discriminative quantification of osseointegration over time. For the comparison of low and high surface osteoconductivity properties, conventional sandblasted, acid-etched chamber surfaces (low surface osteoconductivity) were compared with biomimetically (calcium phosphate) coated ones (high surface osteoconductivity). The implants (4 implants per animal; 88 implants per time point) were inserted into the edentulous maxillae of a total of 66 adult goats with a physiologically osteoporotic masticatory apparatus. Two, 4, and 8 weeks later, they were excised and prepared for a histomorphometric analysis of the volume of neoformed bone within the chamber space and of the bone-to-implant contact (BIC) area. RESULTS: The implants with small chambers did not show significant differences in bone coverage (BIC) nor bone volume (relative and absolute volume), neither as a function of time nor as of implant surface property (low versus high surface osteoconductivity). However, medium and large chambers revealed significant differences respecting both of these parameters over the 8-week postoperative time period. CONCLUSION: The new implant model permits a discriminative quantification of osseointegration in vivo in an osteoporotic bone environment for implants with medium-sized and large-sized chambers. Quantitative assessment of osseointegration is possible, both over time and as a function of low and high surface osteoconductivity properties.

Association between infection of different strains of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival plaque and clinical parameters in chronic periodontitis.

OBJECTIVE: The aim of this study was to investigate subgingival infection frequencies of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans strains with genetic variation in Chinese chronic periodontitis (CP) patients and to evaluate its correlation with clinical parameters. METHODS: Two multiplex polymerase chain reaction (PCR) assays were developed to detect the 16SrDNA, collagenase (prtC) and fimbria (fimA) genes of P. gingivalis and the 16SrDNA, leukotoxin (lktA) and fimbria-associated protein (fap) genes of A. actinomycetemcomitans in 60 sulcus samples from 30 periodontal healthy subjects and in 122 subgingival plaque samples from 61 patients with CP. The PCR products were further T-A cloned and sent for nucleotide sequence analysis. RESULTS: The 16SrDNA, prtC and fimA genes of P. gingivalis were detected in 92.6%, 85.2% and 80.3% of the subgingival plaque samples respectively, while the 16SrDNA, lktA and fap genes of A. actinomycetemcomitans were in 84.4%, 75.4% and 50.0% respectively. Nucleotide sequence analysis showed 98.62%~100% homology of the PCR products in these genes with the reported sequences. P. gingivalis strains with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ were predominant in deep pockets (>6 mm) or in sites with attachment loss > or =5 mm than in shallow pockets (3~4 mm) or in sites with attachment loss < or =2 mm (P<0.05). P. gingivalis strains with prtC+/fimA+ also showed higher frequency in gingival index (GI)=3 than in GI=1 group (P<0.05). CONCLUSION: Infection of P. gingivalis with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ correlates with periodontal destruction of CP in Chinese. Nonetheless P. gingivalis fimA, prtC genes and A. actinomycetemcomitans lktA gene are closely associated with periodontal destruction, while A. actinomycetemcomitans fap gene is not.

Differential gene expression in the condylar cartilage of growing rabbits with temporomandibular joint anterior disk displacement-A transcriptomic study.

Internal derangement (ID) in the temporomandibular joint (TMJ) comprises a group of clinical problems with relatively high prevalence. However, the temporal changes in gene expression of condylar cartilage during continuous ID remain unclear. The aim of the current study is to investigate by microarray analysis, the differentially-expressed gene pattern in condylar cartilage of rabbits with ID from one to eight weeks of ID progression. Histological results (hematoxylin and eosin staining) indicated that abnormal collagen fiber arrangements, fragmentation of fibrils, and inflammatory cell-infiltration were detected from one to four weeks in joint disc specimens, while newly formed vessels, mucoid degeneration, meniscal tears, and the presence of osteoclasts and osteoblasts were observed at later time points. The microarray analysis revealed 6478 genes among all tested transcripts, to have a greater than two-fold expression change compared to controls. The inflammation-associated gene group including ace and il1ß increased rapidly in the early stage of disease and decreased later. In contrast, bone construction-related genes showed low expression levels at first and increased at later period in the ID progression. The current study also found some genes such as hla2g, which have not been previously reported, to be potentially relevant within ID. Our findings provide useful insights into the pathological mechanism of ID in TMJ.

An animal model for inducing anterior disc displacement of the temporomandibular joint.

AIMS: To develop an animal model of anterior disc displacement (ADD) without the need for opening the temporomandibular joint (TMI) capsule. METHODS: Thirty-two healthy adult Japanese white rabbits were used in this study. Four rabbits were dissected to familiarize the investigators with the anatomy of the TMJ. Sixteen animals were subjected to surgical ADD in the right TMJ, 8 animals had a sham operation, and 4 animals were not operated (normal controls). Four rabbits from the experimental ADD group and 2 from the sham group were sacrificed 1, 2, 4, and 8 weeks, respectively. The rabbits in normal control group were sacrificed at the beginning of the experiment. Animal behaviors as well as macro- and microchanges in the TMJs were investigated. RESULTS: Fifteen right TMJ discs in the 16 experimental rabbits were successfully displaced anteriorly, and the degree of ADD in the experimental group was similar. The mandible of each ADD rabbit deviated to the left side with inclined attrition of the incisors. Some histologic changes appeared in the experimental TMJs. CONCLUSION: This ADD technique without the need for opening the TMJ capsule is effective, and the model is suitable for studying ADD of the TMJ.

Infection frequency of Epstein-Barr virus in subgingival samples from patients with different periodontal status and its correlation with clinical parameters.

OBJECTIVE: To detect the infection frequencies of different genotypes of Epstein-Barr virus (EBV) in subgingival samples from chronic periodontitis (CP) patients, and to discuss the correlation between infection with EBV and clinical parameters. METHODS: Nested-PCR assay was used to detect EBV-1 and EBV-2 in subgingival samples from 65 CP patients, 65 gingivitis patients and 24 periodontally healthy individuals. The amplicons were further identified by restriction fragment length polymorphism analysis (RFLP) with endonucleases Afa I and Stu I. Clinical parameters mainly included bleeding on probing (BOP), probing depth (PD), attachment loss (AL) in six sites of the dentition. RESULTS: In CP patients, gingivitis and periodontally healthy individuals, the infection frequencies were 47.7%, 24.6% and 16.7% for EBV-1, and 15.4%, 7.7% and 0% for EBV-2, respectively. In 2 out of the 65 CP patients co-infection of EBV-1 and EBV-2 was found. The positive rate of EBV-1 in chronic periodontitis patients was higher than that in gingivitis patients (P=0.01) and periodontally healthy individuals (P=0.01). But no significant difference was shown in EBV-1 frequency between gingivitis patients and healthy individuals (P>0.05) or in EBV-2 frequency among the three groups (P>0.05). In CP patients, higher mean BOP value was found in EBV-1 or EBV-2 positive patients than that in EBV negative ones (P<0.01), but with no statistical difference in the mean PD or AL value between EBV positive and negative patients (P>0.05). After initial periodontal treatment, 12 out of the 21 EBV-1 positive CP patients did not show detectable EBV-1 in subgingival samples. CONCLUSION: nPCR plus RFLP analysis is a sensitive, specific and stable method to detect EBV-1 and EBV-2 in subgingival samples. Subgingival infection with EBV-1 is closely associated with chronic periodontitis. Infection of EBV in subgingival samples was correlated with BOP.

[Research on condylar morphology in patients with prolonged unilateral posterior teeth loss with cone beam computed tomography].

OBJECTIVE: This study aimed at using cone beam computed tomography (CBCT) to study the influence ofprolonged unilateral posterior teeth loss on bilateral condylar morphology. METHODS: The CBCT images of 30 patients withprolonged unilateral posterior teeth loss and 30 healthy people as controls were corrected. Mimics 15.0 software was used tomeasure volume, area, distance, and bone density of condyle. The results were statistically analyzed. RESULTS: The volumeand bone density of condylar head and the entire condyle on missing teeth side were less than the contralateral side (P<0.05).The area and bone density of condylar transverse plane were greater than the contralateral side (P<0.05). CONCLUSION: After prolonged unilateral posterior teeth loss, adaptive reconstruction occurs in the bilateral condyles, and condyle of missing teethside is smaller than the contralateral side.

[Condylar morphological changes before and after orthodontic treatment for angle Class I malocclusion adult patients].

PURPOSE: To evaluate the condylar morphological changes in adult Angle Class I malocclusionpatients before and after orthodontic treatment using a cone-beam CT (CBCT). METHODS: Images of 25 adult Angle Class I patients (5 males, 20 females) who had no temporomandibular joint disorder symptom were involved in this study, and Mimics 10.01 software was used to reconstruct the three-dimensional condyle and measure the height of condyle, the area and bone density of the largest cross sectional plane and sagittal plane, and the volume and bone density of the whole and upper three-dimensional condyle before and after orthodontic treatment. Paired t test was used for comparison between pre- and post-treatment condylar metric analysis with SPSS 19.0 software package. RESULTS: After treatment, the area and bone density of the largest cross sectional plane and sagittal plane were reduced significantly(P<0.05). The volume and bone density of the whole three-dimensional condyle and bone density of the upper three-dimensional condyle were reduced significantly(P<0.05). CONCLUSIONS: Adaptive bone remodeling of the condyle may occur due to alternation of occlusion by orthodontic treatment in adult Angle Class I malocclusion patients.

Marked variation between winter and spring gut microbiota in free-ranging Tibetan Macaques (Macaca thibetana).

Variation in the availability and distribution of food resources is a strong selective pressure on wild primates. We explored variation in Tibetan macaque gut microbiota composition during winter and spring seasons. Our results showed that gut microbial composition and diversity varied by season. In winter, the genus Succinivibrio, which promotes the digestion of cellulose and hemicellulose, was significantly increased. In spring, the abundance of the genus Prevotella, which is associated with digestion of carbohydrates and simple sugars, was significantly increased. PICRUSt analysis revealed that the predicted metagenomes related to the glycan biosynthesis and metabolic pathway was significantly increased in winter samples, which would aid in the digestion of glycan extracted from cellulose and hemicellulose. The predicted metagenomes related to carbohydrate and energy metabolic pathways were significantly increased in spring samples, which could facilitate a monkey's recovery from acute energy loss experienced during winter. We propose that shifts in the composition and function of the gut microbiota provide a buffer against seasonal fluctuations in energy and nutrient intake, thus enabling these primates to adapt to variations in food supply and quality.

Gene expression of fibrinolytic factors urokinase plasminogen activator and plasminogen activator inhibitor-1 in rabbit temporo-mandibular joint cartilage with disc displacement.

BACKGROUND: The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling. METHODS: Disc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques. RESULTS: The expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks. CONCLUSIONS: The expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.