1
|
Hu Y, Li H. Effects of unilateral nasal obstruction on mandibular condyle in mice of different ages: An exploration based on H-type angiogenesis coupling osteogenesis. FASEB J 2024; 38:e70082. [PMID: 39344592 DOI: 10.1096/fj.202401273r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 09/01/2024] [Accepted: 09/18/2024] [Indexed: 10/01/2024]
Abstract
Nasal obstruction leads to a hypoxia condition throughout the entire body. In this study, the unilateral nasal obstruction (UNO) mouse model was established by blocking the left nostril of mice. The aim of this study was to investigate the effects of UNO-induced hypoxia on mandibular condyle in juvenile (3-week-old), adolescent (6-week-old) and adult (12-week-old) male C57BL/6J mice from the perspective of H-type angiogenesis coupling osteogenesis. Firstly, UNO exerted a significant inhibitory effect on weight gain in mice of all ages. However, only in adolescent mice did UNO have an obvious detrimental effect on femoral bone mass accrual. Subsequently, micro-computed tomography (CT) analysis of mandibular condylar bone mass revealed that UNO significantly retarded condylar head volume gain but increased condylar head trabecular number (Tb.N) in juvenile and adolescent mice. Furthermore, UNO promoted the ratio of proliferative layer to cartilage layer in condylar cartilage and facilitated the chondrocyte-to-osteoblast transformation in juvenile and adolescent mice. Moreover, although UNO enhanced the positive expression of hypoxia-inducible factor (HIF)-1α in the condylar subchondral bone of mice in all ages, an increase in H-type vessels and Osterix+ cells was only detected in juvenile and adolescent mice. In summary, on the one hand, in terms of condylar morphology, UNO has a negative effect on condylar growth, hindering the increase in condylar head volume in juvenile and adolescent mice. However, on the other hand, in terms of condylar microstructure, UNO has a positive effect on condylar osteogenesis, promoting the increase of condylar Tb.N, chondrocyte-to-osteoblast transformation, HIF-1α expression, H-type angiogenesis and Osterix+ cells in juvenile and adolescent mice. Although the changes in condylar morphology and microstructure caused by UNO have not yet been fully elucidated, these findings improve our current understanding of the effects of UNO on condylar bone homeostasis.
Collapse
Affiliation(s)
- Yun Hu
- Department of Orthodontics, Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou, China
| | - Hegang Li
- Department of Orthodontics, Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou, China
| |
Collapse
|
2
|
Hu Y, Li H. Changes in Craniofacial Morphology Induced by Unilateral Nasal Obstruction in Mice of Different Ages. J Oral Rehabil 2024. [PMID: 39209766 DOI: 10.1111/joor.13849] [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: 04/11/2024] [Revised: 07/30/2024] [Accepted: 08/13/2024] [Indexed: 09/04/2024]
Abstract
BACKGROUND Nasal obstruction in humans leads to mouth breathing and subsequent hypoxia in the entire body. Furthermore, nasal obstruction in growing children affects craniofacial growth and development. OBJECTIVE To investigate the effects of unilateral nasal obstruction (UNO) on craniofacial growth in mice of different ages, particularly on the morphology of the nasomaxillary complex and mandible. METHODS Mice aged 3, 6 and 12 weeks were selected as representatives of juvenile, adolescent and adult stages, respectively. A total of 30 male C57BL/6J mice (10 mice each at the ages of 3, 6 and 12 weeks) were used in this study for a 3-week experiment. The mice in each age stage were randomly and evenly assigned to either the control group (C3+3, C6+3 and C12+3) or the experimental group (E3+3, E6+3 and E12+3). The UNO model in experimental group was constructed by plugging the mouse's left nostril, thereby disrupting its normal nasal breathing pattern and inducing hypoxia. The control group underwent the sham procedure. After 3 weeks, the length, width and height of the cranium, nasomaxillary complex and mandible of each group were measured on two-dimensional images constructed by micro-computed tomography. Furthermore, the impact of UNO on mouse growth was evaluated through the measurement of femoral length. RESULTS In juvenile mice, UNO inhibited the growth of cranial width, cranial height and mandibular length. In adolescent mice, UNO impeded the growth of the femoral length, cranial length, nasomaxillary length and mandibular length. In adult mice, no significant negative effects of UNO on craniofacial growth were found. CONCLUSION Referring to the experimental results, in addition to actively treating nasal obstruction in patients, it is important to monitor the growth of the mandible in juveniles, as well as the nasomaxillary and mandibular growth in adolescents during orthodontic clinical practice.
Collapse
Affiliation(s)
- Yun Hu
- Department of Orthodontics, Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou, China
| | - Hegang Li
- Department of Orthodontics, Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou, China
| |
Collapse
|
3
|
Tseng FF, Li YH, Chen YW. Hard and Soft Tissue Facial Landmarks for Mandibular Angle Reduction: A Clinical Study. Clin Pract 2024; 14:1707-1715. [PMID: 39311286 PMCID: PMC11417696 DOI: 10.3390/clinpract14050136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Revised: 08/18/2024] [Accepted: 08/23/2024] [Indexed: 09/26/2024] Open
Abstract
BACKGROUND Square faces, which are influenced by genetic factors and structural features, are considered undesirable among the Asian population. Surgical interventions, such as mandibular angle reduction, aim to alter these characteristics, though complications may arise. We aimed to investigate the morphology of the mandibular angle and masseter muscle thickness using computed tomography (CT) and to analyze hard and soft tissue correlations to enhance surgical outcomes for patients with square faces. METHODS This retrospective clinical study included 100 Taiwanese patients aged 18-50 years. CT was used to analyze key clinical parameters, including bilateral mandibular width, mandibular divergence angle, ramus height, distance from the mandibular angle to the inferior alveolar nerve (IAN), and the thickness of the masseter muscle. RESULTS Significant correlations were noted between the patients' physical height and weight, mandibular width, ramus height, masseter thickness, and distance from the angle to the IAN. Males exhibited a significantly longer and thicker ramus height (66.48 ± 4.28 mm), greater masseter thickness (15.46 ± 2.35 mm), and greater safety range for mandibular angle reduction surgery (18.35 ± 3.19 mm) (p < 0.00008). Significant correlations were observed among all parameters, except between mandibular width and gonial angle and the distance from the angle to the IAN and between mandibular divergence and masseter muscle thickness (p > 0.1). CONCLUSIONS Our study highlighted the complex interplay among factors that contribute to square facial morphology. Careful preoperative assessments and customized surgical planning are essential for addressing this multifaceted clinical challenge.
Collapse
Affiliation(s)
- Fei-Fan Tseng
- Department of Oral and Maxillofacial Surgery, Tri-Service General Hospital, No. 325, Section 2, Cheng-Kung Road, Neihu, Taipei 114, China
- School of Dentistry, National Defense Medical Center, No. 161, Section 6, Minquan E. Rd., Neihu, Taipei 114, China
| | - Yu-Hsuan Li
- Department of Oral and Maxillofacial Surgery, Tri-Service General Hospital, No. 325, Section 2, Cheng-Kung Road, Neihu, Taipei 114, China
- School of Dentistry, National Defense Medical Center, No. 161, Section 6, Minquan E. Rd., Neihu, Taipei 114, China
| | - Yuan-Wu Chen
- Department of Oral and Maxillofacial Surgery, Tri-Service General Hospital, No. 325, Section 2, Cheng-Kung Road, Neihu, Taipei 114, China
- School of Dentistry, National Defense Medical Center, No. 161, Section 6, Minquan E. Rd., Neihu, Taipei 114, China
| |
Collapse
|
4
|
Tak HJ, Moon JW, Kim JY, Kang SH, Lee SH. Transition of endochondral bone formation at the normal and botulinum-treated mandibular condyle of growing juvenile rat. Arch Oral Biol 2024; 164:105999. [PMID: 38815512 DOI: 10.1016/j.archoralbio.2024.105999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 06/01/2024]
Abstract
OBJECTIVE The aim of this study was to understand the temporal and spatial distribution of canonical endochondral ossification (CEO) and non-canonical endochondral ossification (NCEO) of the normal growing rat condyle, and to evaluate their histomorphological changes following the simultaneous hypotrophy of the unilateral masticatory closing muscles with botulinum toxin (BTX). DESIGN 46 rats at postnatal 4 weeks were used for the experiment and euthanized at postnatal 4, 8, and 16 weeks. The right masticatory muscles of rats in experimental group were injected with BTX, the left being injected with saline as a control. The samples were evaluated using 3D morphometric, histological, and immunohistochemical analysis with three-dimensional regional mapping of endochondral ossifications. RESULTS The results showed that condylar endochondral ossification changed from CEO to NCEO at the main articulating surface during the experimental period and that the BTX-treated condyle presented a retroclined smaller condyle with an anteriorly-shifted narrower articulating surface. This articulating region showed a thinner layer of the endochondral cells, and a compact distribution of flattened cells. These were related to the load concentration, decreased cellular proliferation with thin cellular layers, reduced extracellular matrix, increased cellular differentiation toward the osteoblastic bone formation, and accelerated transition of the ossification types from CEO to NCEO. CONCLUSION The results suggest that endochondral ossification under loading tended to show more NCEO, and that masticatory muscular hypofunction by BTX had deleterious effects on endochondral bone formation and changed the condylar growth vector, resulting in a retroclined, smaller, asymmetrical, and deformed condyle with thin cartilage.
Collapse
Affiliation(s)
- Hye-Jin Tak
- Oral Science Research Center, Yonsei University, College of Dentistry, Seoul, the Republic of Korea
| | - Joo-Won Moon
- Oral Science Research Center, Yonsei University, College of Dentistry, Seoul, the Republic of Korea
| | - Jae-Young Kim
- Dept. of Oral and Maxillofacial Surgery, Yonsei University, College of Dentistry, Seoul, the Republic of Korea
| | - Sang-Hoon Kang
- Dept. of Oral and Maxillofacial Surgery, National Health Insurance Service Ilsan Hospital, Goyang, the Republic of Korea
| | - Sang-Hwy Lee
- Oral Science Research Center, Yonsei University, College of Dentistry, Seoul, the Republic of Korea; Dept. of Oral and Maxillofacial Surgery, Yonsei University, College of Dentistry, Seoul, the Republic of Korea.
| |
Collapse
|
5
|
Li S, Mei L, Chen Q, Gao K, Zheng W, Li Y. Unilateral injection of botulinum toxin type A into the masseter muscle induces mandibular asymmetry in adolescent rats by suppressing the angular process growth. Am J Orthod Dentofacial Orthop 2024; 165:232-244. [PMID: 37897486 DOI: 10.1016/j.ajodo.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 10/30/2023]
Abstract
INTRODUCTION Mandibular asymmetry has negative impacts on maxillofacial aesthetics and psychological well-being. This study investigated the effects of unilateral injection of botulinum toxin type A (BTX-A) into the masseter muscle on mandibular symmetry. METHODS Forty Wistar rats (4-week-old) were divided into 4 groups (n = 10): control, group 1 (1U BTX-A), group 2 (3U BTX-A), and group 3 (1U BTX-A for 3 times). BTX-A was injected into the right masseter of treatment groups. Cone-beam computerized tomography scans were taken before the injection and then at 2 weeks, 4 weeks, and 6 weeks after injection. Histologic and immunohistochemical staining were done for the condylar cartilage. RNA sequencing and quantitative reverse transcription polymerase chain reaction were used to detect gene expression in the angular process. RESULTS In Groups 2 and 3, the right angular process length and the ramus height were reduced 4 weeks after injection, resulting in the mandibular midline deviating to the right side; the right condylar cartilage had reduced thickness and decreased expression of RUNX2, SOX9, and COL II (P <0.05). Two hundred sixty-one genes were differentially expressed (256 downregulated) in the angular process at 3 days post-BTX-A injection, and the calcium signaling pathway was unveiled through the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. Furthermore, TRPC1, Wnt5a, CaMKII, Ctnnb1, and RUNX2 expression were significantly downregulated at 1 and 3 days postinjection. CONCLUSIONS Unilateral injection of BTX-A into the masseter muscle in adolescent rats induces mandibular asymmetry by suppressing the angular process growth on the injected side.
Collapse
Affiliation(s)
- Shijia Li
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Li Mei
- Discipline of Orthodontics, Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Qiuyu Chen
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Kui Gao
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Endodontics and Operative Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Wei Zheng
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
| | - Yu Li
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
| |
Collapse
|
6
|
Kotantoula G, Tsolakis IA, Lyros I, Makrygiannakis MA, Kanareli C, Dalampira M, Tsolakis AI. Effects on Facial Growth Following Masseter Muscle Resection in Growing Rats-A Systematic Review. Animals (Basel) 2023; 13:1680. [PMID: 37238110 PMCID: PMC10215724 DOI: 10.3390/ani13101680] [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: 01/30/2023] [Revised: 05/05/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
An individual's facial appearance is heavily influenced by facial symmetry. In the asymmetric mandible, periosteal apposition and endochondral ossification in one of the condyles may stimulate asymmetric growth of the body. Our aim was to review the impact on the growth following masseter resection. Relevant studies up to October 2022 were retrieved from PubMed, Scopus, and Web of Science. The PICOS method was utilized to determine eligibility, and the SYRCLE risk of bias tool was utilized to provide an estimate of potential bias. A predetermined algorithm was used to search the databases. The results of our systematic review of seven studies indicate that the masseter muscle strongly impacts craniofacial growth and development. Resection of the masseter muscle significantly reduces the sagittal and vertical development of the jaw in rats. In addition, the masseter muscle excision influences the mandibular morphology, including the condylar area, angle, and development direction of the jaw.
Collapse
Affiliation(s)
- Georgia Kotantoula
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Ioannis A. Tsolakis
- Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
- Department of Orthodontics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ioannis Lyros
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Miltiadis A. Makrygiannakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | | | | | - Apostolos I. Tsolakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece
- Department of Orthodontics, Case Western Reserve University, Cleveland, OH 44106, USA
| |
Collapse
|
7
|
Keitoku M, Yonemitsu I, Ikeda Y, Tang H, Ono T. Differential Recovery Patterns of the Maxilla and Mandible after Eliminating Nasal Obstruction in Growing Rats. J Clin Med 2022; 11:jcm11247359. [PMID: 36555975 PMCID: PMC9783669 DOI: 10.3390/jcm11247359] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/01/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Although nasal obstruction (NO) during growth causes maxillofacial growth suppression, it remains unclear whether eliminating the NO affects maxillary and mandibular growth differentially. We aimed to clarify whether eliminating NO can help regain normal maxillofacial growth and to determine the optimal intervention timing. Forty-two 4-week-old male Wistar rats were randomly divided into six groups. Their left nostril was sutured to simulate NO over different durations in the experimental groups; the sutures were later removed to resume nasal breathing. Maxillofacial morphology was assessed using microcomputed tomography. Immunohistochemical changes in hypoxia-inducible factor (HIF)-1α, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) of the condylar cartilage were evaluated to reveal the underlying mechanisms of these changes. Maxillary length was significantly lower in rats with NO for ≥5 weeks. In groups with NO for ≥7 weeks, the posterior mandibular length, ramus height, thickness of the hypertrophic cell layer in the condylar cartilage, HIF-1α levels, and RANKL levels were significantly lower and OPG levels and RANKL/OPG were significantly higher than those in the control group. Our findings suggest that eliminating NO is effective in regaining maxillofacial growth. Moreover, the optimal timing of intervention differed between the maxilla and mandible.
Collapse
|
8
|
Kim TH, Kim CH. Correlation between mandibular morphology and masticatory muscle thickness in normal occlusion and mandibular prognathism. J Korean Assoc Oral Maxillofac Surg 2020; 46:313-320. [PMID: 33122455 PMCID: PMC7609929 DOI: 10.5125/jkaoms.2020.46.5.313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/29/2020] [Accepted: 07/02/2020] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES : The aim of this study was to evaluate the relationship between masticatory muscle thickness and mandibular morphology in young Korean adults with normal occlusion and mandibular prognathism. PATIENTS AND METHODS Multidetector computed tomography (MDCT) was used to measure the masticatory muscle thickness on the right side in 100 Korean young adults (50 normal occlusion group, 50 mandibular prognathism group). Cephalometric analysis was done to measure mandibular morphology. Pearson correlation analysis was done to investigate the relationship between the masticatory muscle thickness and mandibular morphometry. RESULTS The four masticatory muscles showed positive correlation with intergonial width in all subjects. All muscles, except temporalis, positively correlated with height of the ramus and mandibular length. Positive correlation was also observed in all muscles, except medial pterygoid, with thickness of the ramus. In the normal occlusion group, all four masticatory muscles showed positive correlation with intergonial width and ramus thickness. Positive correlation was also observed in all muscles (except lateral pterygoid) with mandibular length. Masseter and lateral pterygoid positively correlated with height of the ramus. In the mandibular prognathism group, all masticatory muscles, except lateral pterygoid, showed positive correlation with intergonial width. The masseter muscle showed negative correlation with ANB. CONCLUSION The results suggest a positive correlation of the thickness of masticatory muscles with both horizontal and vertical dimensions of the mandible. However, thickness of the masseter was found to decrease in patients with increasing severity of mandibular prognathism.
Collapse
Affiliation(s)
- Tae-Ho Kim
- Department of Oral and Maxillofacial Surgery, College of Dentistry, Dankook University, Cheonan, Korea
| | - Chul-Hwan Kim
- Department of Oral and Maxillofacial Surgery, College of Dentistry, Dankook University, Cheonan, Korea
| |
Collapse
|
9
|
Yang W, Podyma-Inoue KA, Yonemitsu I, Watari I, Ikeda Y, Guo X, Watabe T, Ono T. Mechanoresponsive and lubricating changes of mandibular condylar cartilage associated with mandibular lateral shift and recovery in the growing rat. Clin Oral Investig 2020; 24:3547-3557. [DOI: 10.1007/s00784-020-03225-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/23/2020] [Indexed: 10/24/2022]
|
10
|
Saito E, Watari I, Mizumachi-Kubono M, Hsu-Hayashi S, Ono T. Occlusional Modifications Reversibly Alter Aquaporin 5 Expression and Localization in Rat Salivary Glands. Front Physiol 2020; 11:528. [PMID: 32587522 PMCID: PMC7298139 DOI: 10.3389/fphys.2020.00528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/29/2020] [Indexed: 11/22/2022] Open
Abstract
Background Aquaporin 5 (AQP5) is a water channel–forming protein that plays a key role in saliva secretion. A decrease in masticatory function associated with the molar extraction adversely affects the submandibular salivary gland (SMG) in rats, inducing hypertrophic changes in the acinar cells and the expression of AQP5 in acinar cells or intercalated duct of the SMG. However, changes in AQP5 expression and localization in the SMG in association with occlusal modification have not been fully characterized. Methods We examined the influence of the decline and recovery of masticatory function on expression and localization of AQP5 in the rat SMG by inserting and removing an incisor bite plate (IBP). Thirty 5-week-old male Wistar rats were randomly divided into IBP (n = 12), recovery (REC) (n = 6), and control (CON) (n = 12) groups. Each rat in both the IBP and REC groups was fitted with the IBP on its maxillary incisors. Rats without the IBPs served as controls. All rats were fed powder diet and water ad libitum. Rats in the IBP and CON groups were sacrificed after 14 (n = 6) and 28 (n = 6) days after the IBP attachment. In the REC group, the IBP was detached on the 14th day and sacrificed on 28th day after the IBP attachment. AQP5 mRNA expression was quantified by reverse transcription–polymerase chain reaction. Changes in the localization of AQP5 were tracked by immunohistochemical staining. Results Attachment of IBP resulted in a decrease in the expression of AQP5 in the IBP group. Changes in the localization of AQP5 were observed between 14 and 28 days in the IBP group. In contrast, changes in the expression and localization of AQP5 were not observed in the REC group. Conclusion Findings suggested that a loss of molar occlusion, due to the IBP attachment, altered AQP5 expression and localization in the rat SMG. However, removal of the bite plate allowed the recovery of both AQP5 expression and its normal localization in the SMGs.
Collapse
Affiliation(s)
- Eri Saito
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ippei Watari
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mariko Mizumachi-Kubono
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Sumire Hsu-Hayashi
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Ono
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| |
Collapse
|
11
|
Influence of liquid diet feeding on calcitonin gene-related peptide-like immunoreactive nerve fibers in rat temporomandibular joints during growth period. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.odw.2007.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
12
|
Tang H, Yonemitsu I, Ikeda Y, Watakabe K, Shibata S, Hosomichi J, Ono T. Effects of unilateral nasal obstruction on the characteristics of jaw-closing muscles in growing rats. Angle Orthod 2018; 89:102-110. [PMID: 30221984 DOI: 10.2319/021918-132.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Mouth breathing caused by nasal obstruction (owing to abnormal pressure of masticatory muscles) affects craniofacial growth and development. The influence of unilateral nasal obstruction on jaw-closing muscles was investigated in rats to reveal one of the etiologic mechanisms. MATERIALS AND METHODS Forty 8-day-old male Wistar rats were used in this study. Experimental rats were subjected to left-sided nasal obstruction by burning the external nostril tissue at the age of 8 days. Pulse oxygen saturation was recorded each week. Morphologic changes were evaluated by staining with hematoxylin and eosin (to assess the cross-sectional area) and by adenosine triphosphatase activity staining (to assess the myosin heavy chain isoform composition). Immunohistochemical and reverse transcription quantitative real-time polymerase chain reaction analyses of tumor necrosis factor-α and glucose transporter 4 were carried out at 5 and 9 weeks of age. RESULTS The cross-sectional area of the jaw-closing muscles was lower in the experimental group at 9 weeks of age. The percentage of myosin heavy chain-2a in masseter muscles was increased in the experimental group compared with the control group. An increase in the tumor necrosis factor-α messenger RNA and protein levels and a decrease in the glucose transporter 4 messenger RNA and protein levels at 5 and 9 weeks of age in the jaw-closing muscles in the experimental group were noted. CONCLUSIONS Unilateral nasal obstruction could affect the morphology and contractile characteristics of jaw-closing muscles during growth in rats.
Collapse
|
13
|
Kesterke MJ, Judd MA, Mooney MP, Siegel MI, Elsalanty M, Howie RN, Weinberg SM, Cray JJ. Maternal environment and craniofacial growth: geometric morphometric analysis of mandibular shape changes with in utero thyroxine overexposure in mice. J Anat 2018; 233:46-54. [PMID: 29611183 DOI: 10.1111/joa.12810] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2018] [Indexed: 12/18/2022] Open
Abstract
An estimated 3% of US pregnancies are affected by maternal thyroid dysfunction, with between one and three of every 1000 pregnancies being complicated by overactive maternal thyroid levels. Excess thyroid hormones are linked to neurological impairment and excessive craniofacial variation, affecting both endochondral and intramembranous bone. Using a geometric morphometric approach, this study evaluates the role of in utero thyroxine overexposure on the growth of offspring mandibles in a sample of 241 mice. Canonical variate analysis utilized 16 unilateral mandibular landmarks obtained from 3D micro-computed tomography to assess shape changes between unexposed controls (n = 63) and exposed mice (n = 178). By evaluating shape changes in the mandible among three age groups (15, 20 and 25 days postnatal) and different dosage levels (low, medium and high), this study found that excess maternal thyroxine alters offspring mandibular shape in both age- and dosage-dependent manners. Group differences in overall shape were significant (P < 0.001), and showed major changes in regions of the mandible associated with muscle attachment (coronoid process, gonial angle) and regions of growth largely governed by articulation with the cranial base (condyle) and occlusion (alveolus). These results compliment recent studies demonstrating that maternal thyroxine levels can alter the cranial base and cranial vault of offspring, contributing to a better understanding of both normal and abnormal mandibular development, as well as the medical implications of craniofacial growth and development.
Collapse
Affiliation(s)
| | - Margaret A Judd
- Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mark P Mooney
- Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Orthodontics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Communication Sciences and Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michael I Siegel
- Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Orthodontics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | - R Nicole Howie
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Seth M Weinberg
- Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - James J Cray
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| |
Collapse
|
14
|
Volumetric Analysis of 700 Mandibular Condyles Based Upon Cone Beam Computed Tomography. J Craniofac Surg 2018; 29:506-509. [DOI: 10.1097/scs.0000000000004136] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
15
|
Abdala-Júnior R, Cortes ARG, Aoki EM, Ferreira S, Luz JGC, Arita ES, de Oliveira JX. Impact of Temporomandibular Joint Discectomy on Condyle Morphology: An Animal Study. J Oral Maxillofac Surg 2017; 76:955.e1-955.e5. [PMID: 29362166 DOI: 10.1016/j.joms.2017.12.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/20/2017] [Accepted: 12/20/2017] [Indexed: 11/18/2022]
Abstract
PURPOSE Temporomandibular disorders lead to parafunctional activity that may alter bone remodeling of mandibular components. This animal study aimed to assess the impact of temporomandibular joint discectomy on condylar bone microarchitecture. MATERIALS AND METHODS A total of 30 one-month-old Wistar rats were assessed and divided into 3 equal groups (2 test groups and 1 control group) of 10. The first test group underwent disc removal, the second test group underwent disc and condylar cartilage removal, and the 10 remaining rats were analyzed as sham-operated controls, following a split-mouth design. The rats were killed humanely 2 months after surgery, and the respective mandibles were scanned with micro-computed tomography for quantitative morphometric analysis. RESULTS There were significant differences among the 3 groups analyzed (disc removal, disc and condylar cartilage removal, and sham-operated control) for bone volume fraction (ratio of bone volume to total volume, P = .044), structure model index (P < .001), fractal dimension (P = .024), and porosity (P = .023). In addition, operated and contralateral nonoperated sides significantly differed for all variables in at least 1 of the test groups (P < .05) but not in the control group (P > .05). CONCLUSIONS Within the limitations of this study, our results suggest that discectomy may lead to alterations of the mandibular condylar morphology.
Collapse
Affiliation(s)
- Reinaldo Abdala-Júnior
- Graduate Student, Oral Radiology Division, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil.
| | - Arthur Rodriguez Gonzalez Cortes
- Postgraduate Fellow, Oral Radiology Division, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil; Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA; and Harvard Medical School, Boston, MA
| | - Eduardo Massaharu Aoki
- Graduate Student, Oral Radiology Division, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil
| | - Simone Ferreira
- Researcher, Department of Oral Surgery, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil
| | - João Gualberto Cerqueira Luz
- Associate Professor, Department of Oral Surgery, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil
| | - Emiko Saito Arita
- Associate Professor, Oral Radiology Division, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil
| | | |
Collapse
|
16
|
Kanaguchi Arita A, Yonemitsu I, Ikeda Y, Miyazaki M, Ono T. Low-intensity pulsed ultrasound stimulation for mandibular condyle osteoarthritis lesions in rats. Oral Dis 2017; 24:600-610. [DOI: 10.1111/odi.12798] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/26/2017] [Accepted: 10/18/2017] [Indexed: 11/30/2022]
Affiliation(s)
- A Kanaguchi Arita
- Department of Orthodontic Science; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - I Yonemitsu
- Department of Orthodontic Science; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - Y Ikeda
- Department of Orthodontic Science; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - M Miyazaki
- Department of Orthodontic Science; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - T Ono
- Department of Orthodontic Science; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| |
Collapse
|
17
|
Spassov A, Toro-Ibacache V, Krautwald M, Brinkmeier H, Kupczik K. Congenital muscle dystrophy and diet consistency affect mouse skull shape differently. J Anat 2017; 231:736-748. [PMID: 28762259 DOI: 10.1111/joa.12664] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2017] [Indexed: 12/17/2022] Open
Abstract
The bones of the mammalian skull respond plastically to changes in masticatory function. However, the extent to which muscle function affects the growth and development of the skull, whose regions have different maturity patterns, remains unclear. Using muscle dissection and 3D landmark-based geometric morphometrics we investigated the effect of changes in muscle function established either before or after weaning, on skull shape and muscle mass in adult mice. We compared temporalis and masseter mass and skull shape in mice with a congenital muscle dystrophy (mdx) and wild type (wt) mice fed on either a hard or a soft diet. We found that dystrophy and diet have distinct effects on the morphology of the skull and the masticatory muscles. Mdx mice show a flattened neurocranium with a more dorsally displaced foramen magnum and an anteriorly placed mandibular condyle compared with wt mice. Compared with hard diet mice, soft diet mice had lower masseter mass and a face with more gracile features as well as labially inclined incisors, suggesting reduced bite strength. Thus, while the early-maturing neurocranium and the posterior portion of the mandible are affected by the congenital dystrophy, the late-maturing face including the anterior part of the mandible responds to dietary differences irrespective of the mdx mutation. Our study confirms a hierarchical, tripartite organisation of the skull (comprising neurocranium, face and mandible) with a modular division based on development and function. Moreover, we provide further experimental evidence that masticatory loading is one of the main environmental stimuli that generate craniofacial variation.
Collapse
Affiliation(s)
- Alexander Spassov
- Department of Orthodontics, University Medicine Greifswald, Greifswald, Germany.,Institute of Pathophysiology, University Medicine Greifswald, Karlsburg, Germany
| | - Viviana Toro-Ibacache
- Facultad de Odontología, Universidad de Chile, Santiago de Chile, Chile.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Mirjam Krautwald
- Institute of Pathophysiology, University Medicine Greifswald, Karlsburg, Germany
| | - Heinrich Brinkmeier
- Institute of Pathophysiology, University Medicine Greifswald, Karlsburg, Germany
| | - Kornelius Kupczik
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| |
Collapse
|
18
|
Jiang L, Xie Y, Wei L, Zhou Q, Li N, Jiang X, Gao Y. iTRAQ-based quantitative proteomic analysis on differentially expressed proteins of rat mandibular condylar cartilage induced by reducing dietary loading. Front Med 2017; 11:97-109. [DOI: 10.1007/s11684-016-0496-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/13/2016] [Indexed: 12/24/2022]
|
19
|
Kufley S, Scott JE, Ramirez-Yanez G. The effect of the physical consistency of the diet on the bone quality of the mandibular condyle in rats. Arch Oral Biol 2017; 77:23-26. [PMID: 28160737 DOI: 10.1016/j.archoralbio.2017.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/27/2016] [Accepted: 01/17/2017] [Indexed: 10/20/2022]
Abstract
OBJECTIVE This study aimed to analyze how the physical consistency of the diet affects the bone quality at the mandibular condyle. DESIGN Sixty-three Wistar rats were randomly assigned to three groups. Twenty-two animals composed each group and they were fed with either a liquid, soft or hard diet. Seven animals were sacrificed from each group at days 7, 20, and 40 respectively. Their mandibles were removed and scanned at the postero-superior area of the condyle with a micro-CT scan. RESULTS showed a statistically significant difference for the bone mineral density (p<0.01) and total mineral density (p<0.01), when comparing the hard against the liquid group after seven days. After 20days both, the soft and the liquid diet groups, computed a statistically significant difference demonstrating a significant decrease in the measured values for bone mineral density, bone mineral content, total mineral density, and total mineral content. At day 40, the values stayed lower for the soft and liquid diets, even though they did not reach a significant difference. CONCLUSIONS This study supports the idea that a soft or liquid diet has a negative impact on the bone quality of the mandible, particularly during the periods of more active growing.
Collapse
Affiliation(s)
- Shawna Kufley
- Department of Oral Biology, College of Dentistry, University of Manitoba, D33-800 Bannatyne Avenue, Winnipeg, MB R3E0W2, Canada
| | - James Elliot Scott
- Department of Oral Biology, College of Dentistry, University of Manitoba, D33-800 Bannatyne Avenue, Winnipeg, MB R3E0W2, Canada
| | - German Ramirez-Yanez
- Department of Oral Biology, College of Dentistry, University of Manitoba, D33-800 Bannatyne Avenue, Winnipeg, MB R3E0W2, Canada.
| |
Collapse
|
20
|
Miyazaki M, Yonemitsu I, Takei M, Kure-Hattori I, Ono T. The imbalance of masticatory muscle activity affects the asymmetric growth of condylar cartilage and subchondral bone in rats. Arch Oral Biol 2015; 63:22-31. [PMID: 26669214 DOI: 10.1016/j.archoralbio.2015.11.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 11/13/2015] [Accepted: 11/23/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To examine the effects of imbalance of masticatory muscle activity of the rat mandible on the condylar cartilage and subchondral bone during the growth period. DESIGN Forty 5-week-old male Wistar rats were randomly divided into experimental (n=20) and control (n=20) groups. In the experimental group, the left masseter muscles were resected. The rats were sacrificed at 7 or 9 weeks of age in both groups. Microcomputed tomography was used to determine the three-dimensional morphology and cancellous bone structure. For histological and histochemical examination, 5-μm-thick serial frontal sections of the condyle were stained with toluidine blue and immunostained with asporin and TGF-β1 to evaluate the promotion and inhibition of chondrogenesis. RESULTS In the experimental group, microcomputed tomography analysis showed asymmetric growth; the resected side condyles showed degenerative changes. Histological analysis showed that the total cartilage in the central region of the resected side was significantly thinner than in the non-resected side in the experimental group, as well as in the control group. Compared with the control group, the expression of asporin was significantly higher in the resected side, and significantly lower in the non-resected side. In contrast, the expression of TGF-β1-immunopositive cells in the non-resected side was significantly higher than in the resected side and the control group. CONCLUSIONS These findings imply that lateral imbalance of masseter muscle activity lead to inhibition of chondrogenesis and induce asymmetric formation of the condyle during the growth period.
Collapse
Affiliation(s)
- Mutsumi Miyazaki
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Ikuo Yonemitsu
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
| | - Maki Takei
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Ikuko Kure-Hattori
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Takashi Ono
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| |
Collapse
|
21
|
Mayne RJ, van der Poel C, Woods MG, Lynch GS. Skeletal effects of the alteration of masseter muscle function. AUSTRALASIAN ORTHODONTIC JOURNAL 2015. [DOI: 10.21307/aoj-2020-154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
Aim
To investigate the effects of muscle denervation and the introduction of the β2-adrenoceptor agonist, formoterol, on the relationship between muscles and underlying skeletal growth.
Method
Thirty-one (4-week-old) male Sprague-Dawley rats were assigned to four groups: Surgical Sham; Denervated; Denervated +β2-agonist; and β2-agonist only. The Surgical Sham group had the left masseteric nerve exposed but not sectioned. Both of the denervated groups had the left masseteric nerve exposed and sectioned. The groups receiving the β2-agonist had formoterol directly injected into the left masseter muscle every three days for eight weeks. Sixteen angular and linear skeletal measurements were assessed in the overall craniofacial region and the mandible via standardised digital radiography in three views: lateral head, submento-vertex and right and left disarticulated hemi-mandibles.
Results
The findings indicated that, following surgical denervation of the masseter muscle, there were significant changes in the muscle and in the subsequent development of the underlying skeletal structures. The post-surgical changes were largely offset by the administration of a β2-agonist, formoterol, which attenuated muscle atrophy. However, the administration of the β2-agonist only, without surgical denervation, did not lead to changes in skeletal facial form.
Conclusions
Denervation atrophy of the masseter muscle results in statistically significant changes in the development of the underlying skeleton. The changes, however, are localised to areas of muscle attachment. The administration of the β2-agonist, formoterol, despite its effect on muscle anabolism, does not have a significant effect on underlying skeletal growth.
Collapse
Affiliation(s)
- Robert J. Mayne
- * Orthodontic Unit , University of Melbourne , Melbourne , Australia
| | - Chris van der Poel
- † Department of Physiology , University of Melbourne , Melbourne , Australia
| | - Michael G. Woods
- + Oral and Maxillofacial Surgery Unit , Melbourne Health and Royal Melbourne Hospital , Melbourne , Australia
| | - Gordon S. Lynch
- † Department of Physiology , University of Melbourne , Melbourne , Australia
| |
Collapse
|
22
|
Liu J, Liu SY, Zhao YJ, Gu X, Li Q, Jin ZL, Chen YJ. Effects of occlusion on mandibular morphology and architecture in rats. J Surg Res 2015; 200:533-43. [PMID: 26602038 DOI: 10.1016/j.jss.2015.09.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 08/20/2015] [Accepted: 09/22/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND A rodent occlusal hypofunction model has been widely established in jawbone-related studies. However, the effects of occlusal stimuli, with total elimination of molar contacts, and its rehabilitation on mandibular remodeling remain unclear. MATERIALS AND METHODS Forty-eight 5-wk-old Sprague-Dawley male rats were used. Twenty-four experimental rats underwent occlusal hypofunction by insertion of a bite-raising appliance. Twenty-four rats received no treatment (control group). Two weeks later, half the experimental rats (occlusal hypofunction group) were killed; the appliance was removed from the remaining experimental rats (recovery group) for two additional weeks before killing. Control animals were killed biweekly. Body weight and masseter muscle weight were measured, and the mandibles were subjected to micro-computed tomography to evaluate the mandibular morphology and cortical bone characteristics. The expressions of osteoblast- and osteoclast-related genes were evaluated with quantitative polymerase chain reaction. RESULTS No significant body weight differences were observed between the experimental and control rats. However, lighter masseter muscle, shorter mandibular incisor crown, mandibular body and ramus, and higher mandibular alveolar process and first molar fossae were observed in the occlusal hypofunction group. Moreover, the cortical bone characteristics associated with the expression of osteoblast- and osteoclast-related genes were remarkably different in the central and posterior mandible in the occlusal hypofunction group. At the 2-wk recovery time point after occlusal stimuli, the altered parameters in the masseter and mandible returned to normal levels. CONCLUSIONS Mandibular remodeling via bone turnover is region specific for altered occlusal stimuli. Normal occlusion is an important determinant of the mandibular morphology and architecture.
Collapse
Affiliation(s)
- Jia Liu
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Shi-Yu Liu
- State Key Laboratory of Military Stomatology, Center for Tissue Engineering, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Ya-Juan Zhao
- Department of Stomatology, Hospital Attached to Aeromedicine Institute of PLA, Beijing, People's Republic of China
| | - Xu Gu
- Department of Stomatology, The 461 Hospital of PLA, Changchun, People's Republic of China
| | - Qiang Li
- State Key Laboratory of Military Stomatology, Department of General Dentistry & Emergency, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China.
| | - Zuo-Lin Jin
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China.
| | - Yong-Jin Chen
- State Key Laboratory of Military Stomatology, Department of General Dentistry & Emergency, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China.
| |
Collapse
|
23
|
Hichijo N, Tanaka E, Kawai N, van Ruijven LJ, Langenbach GEJ. Effects of Decreased Occlusal Loading during Growth on the Mandibular Bone Characteristics. PLoS One 2015; 10:e0129290. [PMID: 26062027 PMCID: PMC4465670 DOI: 10.1371/journal.pone.0129290] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 05/06/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Bone mass and mineralization are largely influenced by loading. The purpose of this study was to evaluate the reaction of the entire mandibular bone in response to decreased load during growth. It is hypothesized that decreased muscular loading will lead to bone changes as seen during disuse, i.e. loss of bone mass. METHODS AND FINDINGS Ten 21-day-old Wistar strain male rats were divided into two groups (each n=5) and fed on either a hard- or soft-diet for 11 weeks. Micro-computed tomography was used for the investigation of bone mineralization, bone volume, bone volume fraction (BV/TV) and morphological analysis. Mandibular mineralization patterns were very consistent, showing a lower degree of mineralization in the ramus than in the corpus. In the soft-diet group, mineralization below the molars was significantly increased (p<0.05) compared to the hard diet group. Also, bone volume and BV/TV of the condyle and the masseter attachment were decreased in the soft-diet group (p<0.05). Morphological analysis showed inhibited growth of the ramus in the soft-diet group (p<0.05). CONCLUSION Decreased loading by a soft diet causes significant changes in the mandible. However, these changes are very region-specific, probably depending on the alterations in the local loading regime. The results suggest that muscle activity during growth is very important for bone quality and morphology.
Collapse
Affiliation(s)
- Natsuko Hichijo
- Department of Orthodontics and Dentofacial Orthopedics, Tokushima University Graduate School of Oral Sciences, Tokushima, Japan
| | - Eiji Tanaka
- Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
- Department of Orthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
- * E-mail:
| | - Nobuhiko Kawai
- Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Leo J. van Ruijven
- Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University Amsterdam, Amsterdam, Netherlands
| | - Geerling E. J. Langenbach
- Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
24
|
Ikeda Y, Yonemitsu I, Takei M, Shibata S, Ono T. Mechanical loading leads to osteoarthritis-like changes in the hypofunctional temporomandibular joint in rats. Arch Oral Biol 2014; 59:1368-76. [DOI: 10.1016/j.archoralbio.2014.08.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/01/2014] [Accepted: 08/18/2014] [Indexed: 11/24/2022]
|
25
|
Liu J, Jin ZL, Li Q. Effect of occlusal hypofunction and its recovery on the three-dimensional architecture of mandibular alveolar bone in growing rats. J Surg Res 2014; 193:229-36. [PMID: 25224274 DOI: 10.1016/j.jss.2014.07.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 06/19/2014] [Accepted: 07/09/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUD Normal occlusion is very important for physiological structure of mandible. However, the details of influences of occlusal hypofunction and its recovery on the three-dimensional architecture of mandibular alveolar bone in growing rats are still lacking. MATERIALS AND METHODS Forty-eight growing male Sprague-Dawley rats were randomly divided into normal (n = 24), hypofunctional (n = 12), and recovery (n = 12) groups. The hypofunction group was developed by inserting a bite-raising appliance between the maxillary and mandibular incisors of the rats. Two weeks after insertion, the appliance was removed to result in the recovery group; the experiment continued for two additional weeks. The experimental animals and control animals were killed weekly. In addition to measuring the body weight and masseter muscle weight of the rats, the histomorphology and microstructure of the mandibular alveolar bone were scanned using microcomputed tomography. RESULTS A lighter masseter muscle and a higher and narrower alveolar process were observed in the hypofunction group compared with the control animals (P < 0.05). Mandibular remodeling also occurred in the hypofunctional group, as demonstrated by a smaller trabecular cross-sectional area, looser trabecular bone, decreased bone volume fraction, trabecular thickness, trabecular number, and increased bone surface density and trabecular separation, especially at week 2 (P < 0.05). After removing the anterior bite-opening appliance, the altered masseter muscle weight and architecture of the mandibular alveolar bone were gradually reversed and reached normal levels at the end of the experiment (P > 0.05). CONCLUSIONS A loss of occlusal stimuli can lead into mandibular alveolar bone remodeling, and the recovery of occlusion can restore the altered mandibular architecture in growing rats.
Collapse
Affiliation(s)
- Jia Liu
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China
| | - Zuo-lin Jin
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China.
| | - Qiang Li
- State Key Laboratory of Military Stomatology, Department of General Dentistry & Emergency, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China.
| |
Collapse
|
26
|
Hichijo N, Kawai N, Mori H, Sano R, Ohnuki Y, Okumura S, Langenbach GEJ, Tanaka E. Effects of the masticatory demand on the rat mandibular development. J Oral Rehabil 2014; 41:581-7. [PMID: 24702545 DOI: 10.1111/joor.12171] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2014] [Indexed: 11/28/2022]
Abstract
The influence of masticatory loading stimulus on mandibular development is not fully clear. In this paper, experimental alterations in the daily muscle use, caused by a changed diet consistency, were continuously monitored, while adaptations in bone and cartilage were examined. It is hypothesised that decreased muscular loading will result in a decrease in the growth factor expression and mandible growth. Fourteen 21-day-old Wistar strain male rats were randomly divided into two groups and fed on either a hard or soft diet for 14 weeks. An implanted radio-telemetric device recorded continuously muscle activity of the superficial masseter muscle. Chondroblast proliferation in the condylar cartilage was identified by insulin-like growth factor-1 receptor (IGF-1r) immunostaining. Furthermore, an X-ray was taken for cephalometric analysis. In the soft-diet group, the duty time of the superficial masseter muscle at higher activity levels was significantly lower than that in the hard-diet group. This decrease in muscular loading of the jaw system was accompanied by: a significant reduction in (i) articular cartilage thickness, (ii) expression of IGF-1r immunopositive cells and (iii) mandible ramus height. In conclusion, a decrease in masticatory demand during the growth period leads to insufficient mandibular development.
Collapse
Affiliation(s)
- N Hichijo
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Oral Sciences, The University of Tokushima, Tokushima, Japan
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Ishida T, Yabushita T, Ono T. Functional reversibility of temporomandibular joint mechanoreceptors. Arch Oral Biol 2013; 58:1078-83. [DOI: 10.1016/j.archoralbio.2013.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 01/31/2013] [Accepted: 01/31/2013] [Indexed: 10/27/2022]
|
28
|
Psychological stress alters microstructure of the mandibular condyle in rats. Physiol Behav 2013; 110-111:129-39. [PMID: 23313405 DOI: 10.1016/j.physbeh.2013.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 01/02/2013] [Accepted: 01/06/2013] [Indexed: 11/21/2022]
Abstract
Psychological stress plays an important role in the occurrence and development of temporomandibular joint disorder (TMD). The correlation between psychological factors and TMD has been clinically shown, but the influence of psychological stress on the temporomandibular joint (TMJ) structure still lacks direct evidence. Here, we used communication box to establish the rat model of psychological stress. The stress level of animals was estimated by the elevated plus maze (EPM) test and hormonal assays. The histomorphology and three-dimensional microstructure of the rat condyles were observed by hematoxylin-eosin (HE) staining and Micro-CT, respectively. Compared with control rats, the anxious state of the stressed rats was evidenced by higher plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT), as well as lower ratios of open arm entries and time and lower time spent in open arms after 1, 2, 3, 4 and 5 week(s) post-exposure to psychological stimuli. HE staining and histomorphometric data analysis showed decreased thicknesses of the central and posterior condylar cartilages in stressed rats at weeks 3, 4 and 5, with the most obvious changes in the posterior part characterized by debonding and thinned fibrous layer, thickened proliferative layer, thinned mature layer and hypertrophic layer. Moreover, Micro-CT scanning revealed local lesion of the subchondral bone in the posterior condylar cartilages of stressed rats at week 5. Our findings indicate that pathologic changes of the histomorphology and three-dimensional microstructure occur in the condyles of stressed rats, hinting us a potential link between psychological factors and the pathogenesis or progression of TMD.
Collapse
|
29
|
Ohira A, Ono Y, Yano N, Takagi Y. The effect of chewing exercise in preschool children on maximum bite force and masticatory performance. Int J Paediatr Dent 2012; 22:146-53. [PMID: 21781200 DOI: 10.1111/j.1365-263x.2011.01162.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Mastication is a developing function affected by various factors. There is a need for further research on methods of promoting masticatory function in young children. AIM The aim of this study was to evaluate the effects of gum chewing exercise on the maximum bite force (MBF) and the masticatory performance of preschool children. DESIGN The study population included 98 preschool children age 4-6years. MBF was measured by Occlusal Force-Meter(®) , and masticatory performance values were evaluated by using the colour-changeable chewing gum. The examinations were performed four times with an interval of 4weeks. An exercise group of 70 subjects was instructed to chew the exercise gum twice daily for 5min during a 4-week period. The chewing gum used for this study was specially developed with the physical property of maintaining hardness during chewing. A control group of 28 subjects was instructed not to chew any gum during the study period. RESULTS No significant differences were found between the exercise group and the control group in MBF and a* values at the start of the study. After 4weeks of chewing exercise, MBF and a* values were significantly increased in the exercise group compared with those of the control group. These increases were maintained for 4weeks after exercise had finished. CONCLUSIONS Gum chewing exercise is effective to increase MBF and a* values of preschool children and the effects are maintained after exercise completion.
Collapse
Affiliation(s)
- Akira Ohira
- Division of Oral Health Sciences, Developmental Oral Health Science, Department of Orofacial Development and Function, Graduate School of Medical and Dental Sciences, Tokyo, Japan.
| | | | | | | |
Collapse
|
30
|
Kuroda Y, Yonemitsu I, Hosomichi J, Watari I, Takei M, Ishida Y, Ono T. Intermittent posterior displacement of the rat mandible in the growth period affects the condylar cancellous bone. Angle Orthod 2011; 81:975-82. [DOI: 10.2319/122810-749.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
31
|
Kurusu A, Horiuchi M, Soma K. Relationship between occlusal force and mandibular condyle morphology. Evaluated by limited cone-beam computed tomography. Angle Orthod 2010; 79:1063-9. [PMID: 19852595 DOI: 10.2319/120908-620r.1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To clarify the relationship between occlusal force and mandibular condyle morphology using clinical data. MATERIALS AND METHODS The subjects were 40 female patients with malocclusion. The mandibular condyle morphology was assessed by using limited cone-beam CT imaging. The maximum occlusal force was calculated by using pressure-sensitive films. Maxillofacial morphologies were analyzed by using data from lateral cephalograms. RESULTS Correlation analysis showed that the occlusal force was correlated with the lateral and posterior radii of the condyles, and with the mandibular plane angle to the Frankfort horizontal plane (FH). Moreover, condylar length was significantly correlated with the occlusal plane angle to the FH, the mandibular plane angle to the FH, the ramus inclination, and the posterior facial height (S-Go). Low-occlusal-force patients tended to have smaller mandibular condyles. This size-related difference was more remarkable on the lateral and posterior side. CONCLUSIONS Occlusal force influences not only maxillofacial morphology but also mandibular condyle morphology.
Collapse
Affiliation(s)
- Aya Kurusu
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Science, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
| | | | | |
Collapse
|
32
|
Römer P, Weingärtner J, Proff P, Roldán JC, Reicheneder C. Profiling type I collagen gene expression in growing mandibular structures. Ann Anat 2010; 192:96-100. [PMID: 20149607 DOI: 10.1016/j.aanat.2009.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 11/21/2009] [Accepted: 12/04/2009] [Indexed: 11/19/2022]
Abstract
We conducted a temporal gene expression analysis with type I collagen in the coronoid process, alveolar process and mandibular angle of the rat. We observed gene expression cross-sectionally across different important physiological time points in the rat postnatal life in order to observe in which developmental stage mandibular development mainly occur. This study indicates prominent type I collagen expression at day 10 postpartum in the mandibular ramus and at day 21 in the alveolar process. These findings correspond well with previously obtained data from proliferation studies in facial bone suggesting that craniofacial growth in the rat occurs mainly between days 10 and 21.
Collapse
Affiliation(s)
- P Römer
- Department of Orthodontics, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
| | | | | | | | | |
Collapse
|
33
|
Holton NE, Franciscus RG, Nieves MA, Marshall SD, Reimer SB, Southard TE, Keller JC, Maddux SD. Sutural growth restriction and modern human facial evolution: an experimental study in a pig model. J Anat 2010; 216:48-61. [PMID: 19929910 PMCID: PMC2807975 DOI: 10.1111/j.1469-7580.2009.01162.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2009] [Indexed: 11/30/2022] Open
Abstract
Facial size reduction and facial retraction are key features that distinguish modern humans from archaic Homo. In order to more fully understand the emergence of modern human craniofacial form, it is necessary to understand the underlying evolutionary basis for these defining characteristics. Although it is well established that the cranial base exerts considerable influence on the evolutionary and ontogenetic development of facial form, less emphasis has been placed on developmental factors intrinsic to the facial skeleton proper. The present analysis was designed to assess anteroposterior facial reduction in a pig model and to examine the potential role that this dynamic has played in the evolution of modern human facial form. Ten female sibship cohorts, each consisting of three individuals, were allocated to one of three groups. In the experimental group (n = 10), microplates were affixed bilaterally across the zygomaticomaxillary and frontonasomaxillary sutures at 2 months of age. The sham group (n = 10) received only screw implantation and the controls (n = 10) underwent no surgery. Following 4 months of post-surgical growth, we assessed variation in facial form using linear measurements and principal components analysis of Procrustes scaled landmarks. There were no differences between the control and sham groups; however, the experimental group exhibited a highly significant reduction in facial projection and overall size. These changes were associated with significant differences in the infraorbital region of the experimental group including the presence of an infraorbital depression and an inferiorly and coronally oriented infraorbital plane in contrast to a flat, superiorly and sagittally infraorbital plane in the control and sham groups. These altered configurations are markedly similar to important additional facial features that differentiate modern humans from archaic Homo, and suggest that facial length restriction via rigid plate fixation is a potentially useful model to assess the developmental factors that underlie changing patterns in craniofacial form associated with the emergence of modern humans.
Collapse
Affiliation(s)
- Nathan E Holton
- Department of Orthodontics, University of Iowa, Iowa City, IA 52242, USA.
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Taira K, Iino S, Kubota T, Fukunaga T, Miyawaki S. Effects of Mandibular Advancement plus Prohibition of Lower Incisor Movement on Mandibular Growth in Rats. Angle Orthod 2009; 79:1095-101. [DOI: 10.2319/112608-603r.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Abstract
Introduction: To test the hypothesis that mandibular advancement with the use of a fixed functional appliance combined with prohibition of labial movement of the lower incisors will have no effect on mandibular growth in growing rats.
Materials and Methods: Fifteen 4-week-old male rats were divided into fixed, unfixed, and control groups (n = 5, each). Bite-jumping appliances were used in the fixed and unfixed groups. Sites of bone perforation and the lower incisors were connected with ligature wires in the fixed group. The ramus height, mandibular length, and inclination of lower incisors were examined for 4 weeks, and those values were compared among five intervals and three groups by through one-way analysis of variance models and the Bonferroni multiple comparison test for post hoc comparison.
Results: Increases in ramus height and mandibular length during the experimental period were 1.5 mm and 2.5 mm in the fixed group, 1 mm and 1.5 mm in the unfixed group, and 1.2 mm and 1.9 mm in the control group, respectively. Growth of ramus height and growth of mandibular length in the fixed group were greater than in the unfixed and control groups during the experimental period. The inclination of lower incisors in the unfixed group was increased 8.0 degrees throughout the experimental period, which differed from results obtained in the other groups.
Conclusions: Mandibular growth was accelerated effectively before and during the pubertal period in rats by mandibular advancement with a fixed functional appliance combined with prohibition of labial movement of the lower incisor.
Collapse
Affiliation(s)
- Koji Taira
- a Graduate student, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Shoichiro Iino
- b Assistant Professor, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Takeshi Kubota
- a Graduate student, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tomohiro Fukunaga
- b Assistant Professor, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Shouichi Miyawaki
- c Professor and Chairman, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- Corresponding author: Dr Shouichi Miyawaki, Professor and Chairman, Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan
| |
Collapse
|
35
|
Saleh HA, El-Aziz GA, El-Fark MM, El-Gohary M. Effect of Maternal Lead Exposure on Craniofacial Ossification in Rat Fetuses and the Role of Antioxidant Therapy. Anat Histol Embryol 2009; 38:392-9. [DOI: 10.1111/j.1439-0264.2009.00960.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
36
|
Ishida T, Yabushita T, Soma K. Functional Changes of Temporomandibular Joint Mechanoreceptors Induced by Reduced Masseter Muscle Activity in Growing Rats. Angle Orthod 2009; 79:978-83. [DOI: 10.2319/081108-424.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 10/01/2008] [Indexed: 11/23/2022] Open
Abstract
Abstract
Objective: To determine the influence of masseter muscle activity during growth on the functional characteristics of temporomandibular joint (TMJ) mechanoreceptors.
Materials and Methods: Sixty-six 3-week-old male Wistar rats were divided into an experimental group, in which the masseter muscles were bilaterally resected at 3 weeks of age, and a control group. Single-unit activities of the TMJ mechanoreceptors were evoked by indirect stimulation of passive jaw movement. Electrophysiologic recordings of TMJ units were made at 5, 7, and 9 weeks of age.
Results: During this period, the firing threshold of the TMJ units was significantly lower and the maximum instantaneous frequency of the TMJ units was significantly higher in the experimental group than in the control group.
Conclusion: Reduced masseter activity during the growth period alters the response properties of TMJ mechanoreceptors.
Collapse
Affiliation(s)
- Takayoshi Ishida
- a Graduate Student, Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tadachika Yabushita
- b Clinical Fellow, Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kunimichi Soma
- c Professor and Chairman, Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| |
Collapse
|
37
|
Ozaki M, Kaneko S, Soma K. Masseter muscular weakness affects temporomandibular synovitis induced by jaw opening in growing rats. Angle Orthod 2008; 78:819-25. [PMID: 18298201 DOI: 10.2319/072407-342.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2007] [Accepted: 10/01/2007] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To evaluate the influence of impaired masseter function during growth on the development of temporomandibular synovitis. MATERIALS AND METHODS Sixteen 3-week-old male Wistar rats were classified into four groups. The first group served as control; and in the second group, jaw opening was forced for 3 hours when the rats were 9 weeks old. In the third and fourth groups, the masseter muscles were bilaterally resected at 3 weeks of age, and the rats in the fourth group were additionally forced to open their jaw at 9 weeks of age. All rats were sacrificed at 9 weeks. Temporomandibular joint (TMJ) tissue samples were processed for histology, and evaluated for cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions by immunohistochemistry to examine the inflammatory changes in the synovial membrane. RESULTS The control group showed noninflammatory changes. In the jaw-opening group, vascular dilation and weak COX-2 immunoreactivity were induced by jaw opening in the synovium. In the masseter-resection group, the masseter-resected rats exhibited moderate synovial changes while in the resection with opening group, the masseter-resected rats revealed more significant inflammatory changes including synovial hyperplasia, dilated vasculature, fibrin deposits, and intense immunoreactivity for COX-2 and iNOS, all caused by jaw opening. CONCLUSIONS These results suggest that masseter activity in the growth period is an important factor in the induction of temporomandibular synovitis.
Collapse
Affiliation(s)
- Miho Ozaki
- Department of Orofacial Development and Function, Tokyo Medical and Dental University, Tokyo, Japan.
| | | | | |
Collapse
|
38
|
Abbassy MA, Watari I, Soma K. Effect of experimental diabetes on craniofacial growth in rats. Arch Oral Biol 2008; 53:819-25. [DOI: 10.1016/j.archoralbio.2008.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 01/11/2008] [Accepted: 02/02/2008] [Indexed: 11/25/2022]
|
39
|
Sakurai M, Yonemitsu I, Muramoto T, Soma K. Effects of masticatory muscle force on temporomandibular joint disc growth in rats. Arch Oral Biol 2007; 52:1186-93. [PMID: 17765198 DOI: 10.1016/j.archoralbio.2007.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 06/07/2007] [Accepted: 07/03/2007] [Indexed: 11/19/2022]
Abstract
Biomechanical factors in masticatory function are related to the development of the mandible and the condyle. Previous studies have reported that reduced masticatory muscle force influences mandibular bone formation and chondroblastic proliferation. We examined the importance of compressive force in temporomandibular joint (TMJ) disc growth by reducing the masticatory load. Thirty 3-week-old male Wistar rats were used in this study. In the experimental group, the masseter muscles were bilaterally resected to evaluate the influence of masticatory muscle force on morphology and composition of TMJ disc during growth. No surgery was performed in the control group. The thickness of the TMJ disc was measured to evaluate the morphological changes. The localization of type I collagen and decorin was performed by immunostaining to examine compositional change. Cell proliferation in the disc was identified by insulin-like growth factor-1 receptor (IGF-1r) immunostaining. The disc thickness at each region in the experimental group was reduced compared to the control group. While in the control group, type I collagen and decorin were identified throughout the disc, it was concentrated on the superior portion of the disc at the anterior and posterior bands in the experimental group. The expression of IGF-1r immunopositive cells in the experimental group was also significantly lower than in the control. We conclude that masticatory muscle force is closely related to TMJ disc morphology and composition during growth.
Collapse
Affiliation(s)
- Makoto Sakurai
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8549, Japan.
| | | | | | | |
Collapse
|