ABSTRACT
OBJECTIVE: This study was designed to assess the morphological and histological alterations of the condyle of rats undergoing forward mandibular repositioning via functional appliance. MATERIALS AND METHODS: Functional appliances were mounted onto the upper jaws of rats. Morphological analysis was conducted on micro-CT images of sacrificed animals. Histological changes in condyle were examined by immunohistochemistry using proliferating cell nuclear antigen (PCNA), matrix metalloproteases (MMPs), vascular endothelial growth factor (VEGF), tissue inhibitors of matrix metalloproteinases (TIMP-1), interleukin 1b (IL-1ß), Aggrecan and Type II collagen. Osteoclast activity was identified by tartrate-resistant acid phosphatase (TRAP) staining. RESULTS: Morphological analysis confirmed the forward positioning of the condyles of rats by the appliance, but the position gradually returned to normal on days 14 after treatment. An increase in PCNA positive cells was observed in the posterior region of the condyles on days 7, whereas PCNA positive cells decreased in the anterior region. Aggrecan and Type II collagen localization increased in the posterior region throughout the entire period, but decreased in the anterior region on days 14. In both regions, IL-1ß and VEGF localization was significantly increased for 14 days while MMPs localization was evident throughout the entire period. The TRAP positive cells were significantly elevated on days 3 and 7. CONCLUSIONS: These results suggest that the functional appliance therapy induces significant morphological and histological changes in the anterior and posterior regions of the condyle and subsequently causes adaptive cellular functions such as chondrocyte differentiation and cartilage matrix formation.
Subject(s)
Mandibular Condyle/metabolism , Orthodontic Appliances, Functional , Aggrecans/metabolism , Animals , Collagen Type II/metabolism , Interleukin-1beta/metabolism , Matrix Metalloproteinases/metabolism , Models, Animal , Proliferating Cell Nuclear Antigen/metabolism , Rats, Sprague-DawleyABSTRACT
Dental materials or components of orthodontics devices can fall into a patient's oropharynx, and be swallowed or inhaled. In this paper a short review of accidental foreign body ingestion/aspiration prevention, evaluation, and relevant incident management guidelines are presented. In addition, a case of an accidentally swallowed piece of archwire during a chair side procedure is reported.
Subject(s)
Deglutition , Foreign Bodies/prevention & control , Orthodontic Appliances/adverse effects , Practice Guidelines as Topic , Respiratory Aspiration/prevention & control , Risk Management/methods , Child , Diagnostic Imaging , Esophagus/pathology , Female , Foreign Bodies/therapy , Humans , Intestines/pathology , Oropharynx/pathology , Orthodontic Wires/adverse effects , Respiratory Aspiration/therapyABSTRACT
OBJECTIVE: To evaluate cellular hypertrophic activities in the mandibular condylar cartilage (MCC) and the glenoid fossa (GF) during mandibular advancement in the temporomandibular joint (TMJ) of Sprague-Dawley rats, as evidenced by fibroblast growth factor 8 (FGF8). METHODS AND MATERIALS: Fifty-five female 24-day-old Sprague-Dawley rats were randomly divided into four experimental and control groups, with a mandibular advancement appliance on the experimental rats' lower incisors. The rats were euthanized on days 3, 14, 21, and 30 of the study, and their TMJ was prepared for a immunohistochemical staining procedure to detect FGF8. RESULTS: FGF8 expression was significantly higher among the experimental rats (P â=â .002). Patterns of ascension and descension of FGF8 expression were similar in experimental and control samples. The results show an overall enhanced osteogenic transition occurring in both the MCC and the GF in experimental rats in comparison with controls. The level of cellular changes in the MCC is remarkably higher than in the GF. CONCLUSION: In the MCC and the GF, cellular morphologic and hypertrophic differentiations increase significantly during mandibular advancement. It is also concluded that endochondral ossification in the MCC and intramembranous ossification in the GF occur during adaptive remodeling.
Subject(s)
Fibroblast Growth Factor 8/biosynthesis , Mandibular Advancement , Temporomandibular Joint/metabolism , Temporomandibular Joint/pathology , Adaptation, Physiological , Animals , Bone Remodeling , Cartilage, Articular/metabolism , Cartilage, Articular/pathology , Chondrogenesis , Female , Hypertrophy/pathology , Mandibular Condyle/metabolism , Mandibular Condyle/pathology , Osteogenesis , Random Allocation , Rats , Rats, Sprague-Dawley , Temporal Bone/metabolism , Temporal Bone/pathologyABSTRACT
OBJECTIVES: To histologically and immunohistochemically assess the pattern of expression of bone morphogenic proteins 2 and 4 (BMP2/4) and proliferating cell nuclear antigen (PCNA) in response to bite jumping appliances in the condylar cartilage and the glenoid fossa. MATERIALS AND METHODS: Fifty-five 4-week-old female Sprague-Dawley rats were randomly divided into four experimental and four control groups. Bite-jumping appliances were fitted to the experimental animals. The rats were sacrificed at 3, 14, 21, and 30 days, and the temporomandibular structures were analyzed histologically and immunohistochemically. RESULTS: The expression of BMP2/4 in response to bite-jumping appliances was statistically significant in the condylar cartilage and the glenoid fossa. Cell proliferation was not significant. CONCLUSION: BMP2/4 plays an important role in bone formation in response to mandibular advancement by accelerating and enhancing the differentiation of mesenchymal cells into bone-forming cells.
