1
|
Wang Y, Gao W, Liang C, Jia F, Geng W. Influence on the temporomandibular joint induced by mandibular malpositioning caused by vertical dimension elevation and occlusal loss in adult rats: An imaging, histological and immunohistochemical study. J Oral Rehabil 2024. [PMID: 38783585 DOI: 10.1111/joor.13739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/26/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND Mandibular malpositioning may result in an abnormal concentration of stresses within the temporomandibular joint (TMJ) in adult rats, which may further lead to a series of pathological changes, such as articular cartilage wear, subchondral bone sclerosis and osteophyte formation. However, the pathological and adaptive changes in condylar cartilage caused by different stress distributions are still controversial. OBJECTIVE The aim of this study was to observe the effect of sagittal changes in mandibular position on condylar cartilage by changing the occlusal vertical dimension (OVD) in adult rats. METHODS Fifteen-week-old female rats were divided into three groups: control (CON), increased OVD (iOVD) and loss of occlusion (LO) groups. An occlusal plate and tooth extraction were used to establish the animal model. TMJ samples of the experimental and CON groups were observed and investigated by bone morphological, histomorphological and immunohistochemical staining analyses at 3 days, 1 week, 2 weeks, 4 weeks and 8 weeks. Weight curves were plotted. RESULTS Micro-computed tomography showed that, compared with the CON group, cartilage destruction followed by repair occurred in both experimental groups, which was similar to the trend observed in haematoxylin-eosin staining. All experimental results for the iOVD group showed an approximately similar time trend. Compared with the iOVD group, the toluidine blue and immunohistochemical staining results in the LO group showed no obvious change trend over time. CONCLUSION Compared with occlusal loss, an increase in OVD caused faster and more severe damage to condylar cartilage, and subchondral bone repair occurred later.
Collapse
Affiliation(s)
- Yue Wang
- Department of Dental Implant Centre, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Wenmo Gao
- Department of Dental Implant Centre, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Chao Liang
- Department of Dental Implant Centre, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Fangwen Jia
- Department of Dental Implant Centre, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Wei Geng
- Department of Dental Implant Centre, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| |
Collapse
|
2
|
De Carli E, Lagou A, Kiliaridis S, Denes BJ. Mandibular condyle changes in rats with unilateral masticatory function. Orthod Craniofac Res 2023; 26:37-45. [PMID: 35347850 PMCID: PMC10084257 DOI: 10.1111/ocr.12575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/20/2022] [Accepted: 03/24/2022] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Certain malocclusions or unilateral tooth loss can lead to asymmetric functional load of the two mandibular sides during mastication and induce skeletal asymmetries to the condylar process of growing individuals. However, in adults, asymmetric function may have a different impact. The aim of the present study was to investigate three-dimensionally the effects of unilateral masticatory function on the condylar process morphology in growing and adult rats and the adaptive processes to differential condylar loading. MATERIALS AND METHODS Fifty-six growing and adult Wistar rats aged 4 and 26 weeks respectively were obtained. The maxillary right molars of the experimental animals were extracted and all animals were followed for 12 weeks. Three-dimensional images were obtained by an in-vivo microcomputed tomography (micro-CT) examination. The following measurements were studied: condylar process height, condylar base width, and condylar cross-sectional surface. RESULTS While no differences were found with regards to condylar process height and base width, the cross-section of the condyle on the extraction side did not increase during growth in the young rats. No such differences were found in adults. Young rats had statistically significantly shorter condylar height, base width and cross-sectional surface than the adult rats and showed significant growth of these structures during the experimental period. CONCLUSION Condylar height and base width growth are not hindered by reduced occlusal function, contrary to the average cross-sectional surface, which implies that the condyle form of growing individuals becomes thinner while maintaining its length, in the absence of occlusal stimuli. The condyle of adult rats with extractions is less affected by occlusion changes.
Collapse
Affiliation(s)
- Enrico De Carli
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Aikaterini Lagou
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Stavros Kiliaridis
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Orthodontics and Dentofacial Orthopedics, Dental School/Medical Faculty, University of Bern, Bern, Switzerland
| | - Balazs J Denes
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| |
Collapse
|
3
|
Yu JL, Tangutur A, Thuler E, Evans M, Dedhia RC. The role of craniofacial maldevelopment in the modern OSA epidemic: a scoping review. J Clin Sleep Med 2022; 18:1187-1202. [PMID: 34984972 DOI: 10.5664/jcsm.9866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES There is increasing recognition that environmental factors affect human craniofacial development and our risk for disease. A scoping review of the literature was performed looking at environmental influences on craniofacial development to better understand this relationship and investigate what further study is needed to determine how this relationship may impact obstructive sleep apnea. METHODS A comprehensive literature search was performed using the Ovid Medline database from inception to May, 2020 with relevance to craniofacial development in 5 clinically-oriented variables: diet, secular change, breastfeeding/non-nutritive sucking habits (NNSH), nasal obstruction/mouth breathing, and masticatory muscle function. The Oxford Centre for Evidence-Based Medicine Levels of Evidence (LoE) was used to assess studies based on study design. RESULTS 18,196 articles were initially identified, of which 260 studies were fully reviewed and 97 articles excluded. The remaining 163 articles were categorized as follows: Secular change (n = 16), Diet (n = 33), Breastfeeding/NNSH (n = 28), Nasal obstruction/Mouth breathing (n = 57), and Masticatory muscle function (n = 35). 93% of included studies reported a significant association between craniofacial morphology and environmental factors. The majority of studies were characterized as low LoE studies with 90% of studies being LoE 4 or 5. CONCLUSIONS The studies in this review suggest that environmental factors are associated with changes in craniofacial development. However, most studies were heterogeneous and low-level studies, making strong conclusions about these relationships difficult. Future rigorous studies are needed to further our understanding of environmental influences on craniofacial development and OSA risk.
Collapse
Affiliation(s)
- Jason L Yu
- Division of Sleep Surgery, Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, PA.,Division of Sleep Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA
| | - Akshay Tangutur
- Division of Sleep Surgery, Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, PA
| | - Eric Thuler
- Division of Sleep Surgery, Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, PA
| | - Marianna Evans
- Division of Sleep Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA
| | - Raj C Dedhia
- Division of Sleep Surgery, Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, PA.,Division of Sleep Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA
| |
Collapse
|
4
|
Koizumi Y, Ishii T, Nishii Y, Nojima K, Sueishi K. Influence of experimental hemi-occlusion on mandibular morphology and internal structure in growing rabbit. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.odw.2010.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yoshiaki Koizumi
- Department of Orthodontics, Tokyo Dental College, 1-2-2 Masago Mihama-ku, Chiba 261-8502, Japan
| | | | | | | | | |
Collapse
|
5
|
Scheidegger R, Koletsi D, Eliades T. The impact of dietary consistency on structural craniofacial components: Temporomandibular joint/condyle, condylar cartilage, alveolar bone and periodontal ligament. A systematic review and meta-analysis in experimental in vivo research. Arch Oral Biol 2018; 94:33-47. [PMID: 29957455 DOI: 10.1016/j.archoralbio.2018.06.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/09/2018] [Accepted: 06/17/2018] [Indexed: 12/09/2022]
Abstract
OBJECTIVE The aim of this systematic review was to provide a comprehensive synthesis of available evidence evaluating the effect of dietary loading on temporomandibular joint/condyle, condylar cartilage, alveolar bone of the mandible and the periodontal ligament in healthy mice and rats. DESIGN Medline via PubMed, EMBASE and Open Grey databases were searched for published and unpublished literature. Search terms included "mandiblular condyle", "alveolar bone", "temporomandibular joint", "condylar cartilage", "periodontal ligament", "rat", "mice". After data extraction, risk of bias (SYRCLE) and reporting quality (ARRIVE) were assessed. Random effects meta-analyses were performed for the outcomes of interest where applicable. RESULTS A total of 33 relevant articles were considered in the systematic review, while only 6 studies were included in the quantitative synthesis. Risk of Bias in all studies was judged to be unclear to high overall, while reporting quality was suboptimal. Comparing soft to hard diet animals, significantly reduced anteroposterior condylar length (4 studies, weighted mean difference: -0.40 mm; 95% CI: -0.47, -0.32; p < 0.001) and width (4 studies, weighted mean difference: -0.043 mm; 95% CI: -0.51, -0.36; p < 0.001) were found in rats. Decreased anteroposterior condylar dimensions were detected for mice as well (2 studies, weighted mean difference: -0.049; 95% CI: -0.56, -0.43; p < 0.001). CONCLUSIONS Overall, there was strong evidence to suggest a significant effect of soft diet on reduced condylar dimensions in rodents; however, there is need for further high quality experimental studies to inform current knowledge on condylar cartilage, alveolar bone and periodontal ligament related outcomes.
Collapse
Affiliation(s)
- Rolf Scheidegger
- Clinic of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland.
| | - Despina Koletsi
- Clinic of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland.
| | - Theodore Eliades
- Clinic of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland.
| |
Collapse
|
6
|
Shinohara Y, Okamoto K, Goh Y, Kiga N, Tojyo I, Fujita S. Inhibition of fibrous adhesion formation in the temporomandibular joint of tenascin-C knockout mice. Eur J Histochem 2014; 58:2337. [PMID: 25578971 PMCID: PMC4289843 DOI: 10.4081/ejh.2014.2337] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 08/31/2014] [Accepted: 09/09/2014] [Indexed: 12/18/2022] Open
Abstract
Tenascin-C (TNC) is a large hexameric extracellular matrix glycoprotein that is expressed in developing organs and tumors. It has been reported that TNC is expressed in inflamed synovial membranes and deformed discs of temporomandibular joint (TMJ) disorder. However, the role of TNC in TMJ is not fully known. In this study, the role of TNC in fibrous adhesion formation of TMJ was examined using TNC knockout (TNCKO) mice. Hypermobility was produced by excessive mouth opening method on the TMJ of both wild-type (WT) and TNCKO mice. TMJ wound healing was compared histologically, and the expression of TNC, fibronectin (FN) and α-smooth muscle actin (α-SMA) in the wounded TMJ was examined by immunohistochemical and immunoblot analyses. Based on histologic analysis, fibrous adhesions were observed in the TMJ of both TNCKO and wild-type (WT) mice after excessive mouth opening. However, fibrous adhesion formation in TNCKO mice occurred later than in WT mice. TNC was expressed in the wounded TMJ disc and mandibular fossa. Although FN and α-SMA expression in the TMJ of TNCKO and WT mice was up-regulated after excessive mouth opening, FN and α-SMA protein levels were higher in WT mice at the same time points. In the wounded TMJ, TNC appears to enhance the expression of FN and α-SMA, and a lack of TNC may reduce fibrous adhesion formation in the TMJ. TNC plays an important role in TMJ wound healing, especially for wounds generated by mechanical stress.
Collapse
|
7
|
Im JH, Kim SG, Oh JS, Lim SC, Ha JM. Influence of unilateral tooth loss in the temporomandibular joint and masseter muscle of rabbits. Oral Surg Oral Med Oral Pathol Oral Radiol 2012; 114:9-16. [PMID: 22732844 DOI: 10.1016/j.tripleo.2011.05.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/10/2011] [Accepted: 05/20/2011] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The purpose of this study was to evaluate the influence of the masticatory system in patients with missing teeth. STUDY DESIGN The influence of tooth loss on the masticatory system was analyzed with the use of bone scintigraphy ((99m)Tc-MDP) and histochemistry. Eight white rabbits (New Zealand, 12 weeks old) were used. The rabbits were divided into 2 groups: 6 weeks and 12 weeks. Teeth were extracted unilaterally in each rabbit under general anesthesia. Six and 12 weeks after extraction, scintigraphy was conducted, and the rabbits were killed and their masseter muscles removed for histochemical analysis. RESULTS The results of bone metabolism (relative ratio) measured by bone scintigraphy were 48.27% at extraction sites and 51.73% at nonextraction sites at 6 weeks and 39.96% at extraction sites and 60.04% at nonextraction sites at 12 weeks. There was a significant difference at 12 weeks (P < .05). Tissue calcium contents and osteoclast counts showed different results between the extraction and nonextraction sites, but these differences did not reach statistical significance. CONCLUSIONS The bone metabolism of temporomandibular joints and histochemical aspects of masticatory muscles may be associated with occlusal alterations following tooth loss.
Collapse
Affiliation(s)
- Jae-Hyung Im
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea
| | | | | | | | | |
Collapse
|
8
|
Magara J, Nozawa-Inoue K, Suzuki A, Kawano Y, Ono K, Nomura S, Maeda T. Alterations in intermediate filaments expression in disc cells from the rat temporomandibular joint following exposure to continuous compressive force. J Anat 2012; 220:612-21. [PMID: 22458657 DOI: 10.1111/j.1469-7580.2012.01501.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The articular disc in the temporomandibular joint (TMJ) that serves in load relief and stabilizing in jaw movements is a dense collagenous tissue consisting of extracellular matrices and disc cells. The various morphological configurations of the disc cells have given us diverse names, such as fibroblasts, chondrocyte-like cells and fibrochondrocytes; however, the characteristics of these cells have remained to be elucidated in detail. The disc cells have been reported to exhibit heterogeneous immunoreaction patterns for intermediate filaments including glial fibrillary acidic protein (GFAP), nestin and vimentin in the adult rat TMJ. Because these intermediate filaments accumulate in the disc cells as tooth eruption proceeds during postnatal development, it might be surmised that the expression of these intermediate filaments in the disc cells closely relates to mechanical stress. The present study was therefore undertaken to examine the effect of a continuous compressive force on the immunoexpression of these intermediate filaments and an additional intermediate filament - muscle-specific desmin - in the disc cells of the TMJ disc using a rat experimental model. The rats wore an appliance that exerts a continuous compressive load on the TMJ. The experimental period with the appliance was 5 days as determined by previous studies, after which some experimental animals were allowed to survive another 5 days after removal of the appliance. Histological observations demonstrated that the compressive force provoked a remarkable acellular region and a decrease in the thickness of the condylar cartilage of the mandible, and a sparse collagen fiber distribution in the articular disc. The articular disc showed a significant increase in the number of desmin-positive cells as compared with the controls. In contrast, immunopositive cells for GFAP, nestin and vimentin remained unchanged in number as well as intensity. At 5 days after removal of the appliance, both the disc and cartilage exhibited immunohistological and histological features in a recovery process. These findings indicate that the mature articular cells are capable of producing desmin instead of the other intermediate filaments against mechanical stress. The desmin-positive disc cells lacked α-smooth muscle actin (α-SMA) in this study, even though desmin usually co-exists with α-SMA in the vascular smooth muscle cells or pericytes. Because the precursor of a pericyte has such an immunoexpression pattern during angiogenesis, there is a further possibility that the formation of new vessels commenced in response to the extraordinary compressive force.
Collapse
Affiliation(s)
- Jin Magara
- Division of Oral Anatomy, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | | | | | | | | | | | | |
Collapse
|
9
|
Mizumachi-Kubono M, Watari I, Ishida Y, Ono T. Unilateral maxillary molar extraction influences AQP5 expression and distribution in the rat submandibular salivary gland. Arch Oral Biol 2012; 57:877-83. [PMID: 22424887 DOI: 10.1016/j.archoralbio.2012.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 01/21/2012] [Accepted: 02/03/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Mastication has been regarded as a crucial factor for maintaining the morphology and function of secretion in salivary glands. Although it is known that occlusion affects mastication, the detailed process for how occlusal changes affect the secretory function of salivary glands is still unknown. Aquaporin 5 (AQP5) is a membrane protein that forms water channels, and plays an important role in water transport. In this study, we investigated the structural changes and alterations in the expression and distribution of AQP5 in the rat submandibular salivary gland (SMG) under occlusal hypofunction after unilateral molar extraction. METHODS Seven-week-old male Wistar rats (n = 36) were used in the study. In the experimental group, all of the right maxillary molars were extracted. Rats with no molar extraction were used as the control group. The rats were euthanized at 7, 14 or 28 days after the procedure, and the right SMGs were isolated and subjected to histological analyses. The expression and distribution of AQP5 were detected by immunohistochemistry. RESULTS Morphological analyses revealed hypertrophic changes in the acinar cells in the experimental group. Immunohistochemical staining of AQP5 was detected in the apical membrane (APM) and intercellular secretory canaliculi of acinar cells in both groups. On the other hand, the AQP5 expression in the APM and intercellular secretory canaliculi of acinar cells was less prominent in the experimental group than in the control group. CONCLUSIONS The present findings suggest that unilateral molar extraction has significant influences on the function of water transport in the rat SMG.
Collapse
Affiliation(s)
- Mariko Mizumachi-Kubono
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Tokyo 113-8549, Japan.
| | | | | | | |
Collapse
|
10
|
Farias-Neto A, Martins APVB, Rizzatti-Barbosa CM. The effect of loss of occlusal support on mandibular morphology in growing rats. Angle Orthod 2012; 82:242-6. [DOI: 10.2319/060711-373.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
| | - Ana Paula Varela Brown Martins
- Graduate student, Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| | - Célia Marisa Rizzatti-Barbosa
- Professor, Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| |
Collapse
|
11
|
Avivi-Arber L, Martin R, Lee JC, Sessle BJ. Face sensorimotor cortex and its neuroplasticity related to orofacial sensorimotor functions. Arch Oral Biol 2011; 56:1440-65. [DOI: 10.1016/j.archoralbio.2011.04.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 04/05/2011] [Accepted: 04/06/2011] [Indexed: 12/20/2022]
|
12
|
Ödman A, Kiliaridis S. Rat as a Model for Studying the Effect of Masticatory Muscle Function on Craniofacial Growth. Semin Orthod 2010. [DOI: 10.1053/j.sodo.2010.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
13
|
Avivi-Arber L, Lee JC, Sessle BJ. Effects of incisor extraction on jaw and tongue motor representations within face sensorimotor cortex of adult rats. J Comp Neurol 2010; 518:1030-45. [DOI: 10.1002/cne.22261] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
14
|
Yokoyama M, Atsumi T, Tsuchiya M, Koyama S, Sasaki K. Dynamic changes in bone metabolism in the rat temporomandibular joint after molar extraction using bone scintigraphy. Eur J Oral Sci 2009; 117:374-9. [DOI: 10.1111/j.1600-0722.2009.00635.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
15
|
Abed GS, Buschang PH, Taylor R, Hinton RJ. Maturational and functional related differences in rat craniofacial growth. Arch Oral Biol 2007; 52:1018-25. [PMID: 17643386 DOI: 10.1016/j.archoralbio.2007.05.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 05/16/2007] [Accepted: 05/24/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND Whilst decreases in masticatory muscle function have been linked with increased prevalences of craniofacial dysmorphology and malocclusion in humans, the relative susceptibility of the different craniofacial components remains poorly understood. METHODS Thirty-two wild-type male Sprague-Dawley rats were randomly assigned to two groups (n=16 each), one raised on a soft diet (SD) and the other on a hard diet (HD). Body weights and three radiographs (lateral, dorso-ventral, and tibial X-rays) were taken at baseline (T1=23 days old) and every 2 weeks thereafter for 8 weeks (T5=79 days old). The X-ray images were scanned, standardised points were digitised, and linear measurements were calculated. Multilevel statistical models were used to describe longitudinal absolute growth changes and statistically evaluate group differences. Relative maturity curves were generated for each measurement based on the animals' T5 status. The experimental effect was calculated as the absolute and relative growth differences between the HD and SD groups. RESULTS The HD group was significantly heavier than the SD group at T5, but no differences in tibial length were observed. Eight of the 20 craniofacial measurements (40%) showed significant size differences at the end of the experiment, with the SD group showing deficiencies in each instance. All of the vertical measurements, as well as most of the mandibular (67%) and transverse (67%) measures, showed absolute growth deficits in the SD group. Relative maturity curves demonstrated considerable variation among craniofacial structures (ranging from 42 to 98%). The neurocranial measures were the most mature; the mandibular measures were the least mature; the viscerocranial measures, which were most variable, tended to be intermediate. Whilst unrelated to the absolute experimental effect, the structures' relative maturity explained almost 70% (r=-0.82) of the relative experimental effect. CONCLUSION The results of this study support the notion that masticatory function is a key determinant of the craniofacial growth pattern and that its effects are modulated by the relative growth potential of the different craniofacial components.
Collapse
Affiliation(s)
- George S Abed
- Department of Orthodontics, Baylor College of Dentistry, 3302 Gaston Ave., Dallas, TX 75246, USA
| | | | | | | |
Collapse
|
16
|
Structural features of incremental line-like striations in mandibular condylar cartilage of c-src-deficient mice. Arch Oral Biol 2006; 51:951-9. [DOI: 10.1016/j.archoralbio.2006.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 04/17/2006] [Accepted: 05/22/2006] [Indexed: 11/21/2022]
|
17
|
|
18
|
Sato I, Uneno R, Miwa Y, Sunohara M. Distribution of tenascin-C and tenascin-X, apoptotic and proliferating cells in postnatal soft-diet rat temporomandibular joint (TMJ). Ann Anat 2006; 188:127-36. [PMID: 16551009 DOI: 10.1016/j.aanat.2005.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We immunohistochemically examined the relationship between the distribution of extracellular matrix glycoproteins (tenascin-C and tenascin-X), apoptotic cells, and proliferating cells to determine the effect of a soft diet in the rat temporomandibular joint (TMJ) over a period of 4 weeks from 21 days of age. Using confocal Laser scanning microscopy, strong expression of tenascin-C and tenascin-X was found in the soft-diet group, mainly from the proliferative layer to the cartilage layer of the condyle, and posterior and anterior regions of the disk, in contrast to that of the control group, which was fed a hard diet. The number of proliferating cells in the soft-diet group was lower than that in the control group and was especially low in the calcified zone and proliferative cell layer of the sagittal section of the TMJ. The apoptotic cells were found mainly in the endochondral ossification layer of the condyle. On day 28 in the soft-diet group, they were also highly concentrated in endochondral ossification layer of the anterior condyle beneath the disk. A few apoptotic cells were observed in the synovial membrane and the disk. These distributions reflect the process of replication in the TMJ in accordance with the feeding of a soft diet.
Collapse
Affiliation(s)
- Iwao Sato
- Department of Anatomy, School of Dentistry at Tokyo, Nippon Dental University, 1-9-20 Fujimi Chiyoda-Ku, Tokyo 102-8159, Japan.
| | | | | | | |
Collapse
|
19
|
Ramirez-Yañez GO, Daley TJ, Symons AL, Young WG. Incisor disocclusion in rats affects mandibular condylar cartilage at the cellular level. Arch Oral Biol 2004; 49:393-400. [PMID: 15041487 DOI: 10.1016/j.archoralbio.2003.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2003] [Indexed: 10/26/2022]
Abstract
UNLABELLED The effect of altered occlusion on the mandibular condylar cartilage remains unclear. OBJECTIVE This study investigated the effect of unilateral incisor disocclusion on cartilage thickness, on mitotic activity and on chondrocytes maturation and differentiation in the mandibular condylar cartilage of rats. DESIGN The upper and lower left incisors were trimmed 2mm every second day in five rats. In other five rats, the incisor occlusion was not altered. Condylar tissues from both sides of each mandible were processed and stained for Herovici's stain and immunohistochemistry for bromodeoxyuridine (BrdU), transforming growth factor-beta1 (TGF-beta1), alkaline phosphatase (ALP) and osteocalcin (OCN). Measurements of cartilage thickness and the numbers of immunopositive cells for each antibody were analysed by one-way analysis of variance (ANOVA). RESULTS No significant differences were observed in cartilage thickness after 7 days of unilateral incisor disocclusion. However, the numbers of immunopositive cells for BrdU as a marker of DNA synthesising cells, TGF-beta1 as a marker of chondrocytes differentiation, and ALP and OCN as markers of chondrocytes maturation, were significant higher in the cartilage cells on both sides when incisor occlusion was unilaterally altered. Interestingly, alkaline phosphatase was highly expressed on the condylar side of incisor disocclusion, whereas osteocalcin was highly expressed on the side opposite to the incisor disocclusion. CONCLUSIONS It is demonstrated that after 7 days, unilateral incisor disocclusion affects the mandibular condylar cartilage at the cellular level by increasing the mitotic activity and by accelerating chondrocytes maturation. Chondrocytes maturation appears more accelerated on the side opposite to incisor disocclusion.
Collapse
Affiliation(s)
- G O Ramirez-Yañez
- Department of Oral Biology and Pathology, School of Dentistry, The University of Queensland, QLD, Australia.
| | | | | | | |
Collapse
|