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1.
Odontology ; 111(1): 20-32, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35536282

RESUMO

OBJECTIVES: This systematic review was to compare the effects of interventions for the management of fear and anxiety for dental treatments. METHODS: This research project was applied to PubMed, CENTRAL, Web of Science, Cochrane library databases. The last search was run on March 31st, 2021. A list of references of relevant articles and previous reviews were checked. Qualitative and quantitative analyses were performed. RESULTS: A total of 20 eligible randomized controlled trials were included, and 969 participations in experimental group and 892 participations in the control group were involved. Anxiety levels decreased more in intervention groups than in control groups (Z = 3.47, P = 0.0005, SMD = - 0.62, 95% CI - 0.98 to - 0.27). For adults, there was statistical difference between experimental and control groups [Z = 2.14, P = 0.03, 95% CI - 0.54 (- 1.03, - 0.04)], while there was not no such statistical difference in children and adolescents [Z = 1.62, P = 0.11, 95% CI - 0.60 (- 1.32, 0.13)]. Patients experienced a significant decrease in anxiety level using sedation drugs [Z = 2.44, P = 0.01, 95% CI - 0.61 (- 1.10, - 0.12)] and audio-visual distractions [Z = 3.1, P = 0.002, 95% CI - 0.86 (- 1.40, - 0.32)]. For the informative intervention groups, patients did not show significant difference than control groups [Z = 1.22, P = 0.22, 95% CI - 0.55 (- 1.43, 0. 33)]. There was no statistical difference in vital signs [Z = 1.39, P = 0.16, 95% CI - 0.25 (- 0.61, 0.10)] and pain levels [Z = 0.69, P = 0.49; SMD = - 0.06, 95% CI (0.27, 0.11)] between intervention and control groups. CONCLUSIONS: Interventions should be used in managing anxiety and fear for dental treatment. It might be effective for anxiety alleviating for adults, but there was a low certainty of evidence that interventions could reduce anxiety level in children and adolescents. Sedation drugs and audio-visual distractions might be useful for managing dental fear and anxiety. Pain levels and vital signs could not be improved form our study. High-quality randomized clinical trials are required for further study.


Assuntos
Ansiedade , Ansiedade ao Tratamento Odontológico , Dor , Adolescente , Adulto , Criança , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
2.
J Evid Based Dent Pract ; 23(4): 101919, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38035896

RESUMO

OBJECTIVES: The present study aimed to systematically review the current randomized clinical trials (RCTs) with respect to computer-aided design/computer-aided manufactured (CAD/CAM) techniques in the process of implant planning, placement, and rehabilitation. MATERIALS AND METHODS: Four independent reviewers conducted an electronic and manual literature search using several databases, including the National Library of Medicine (MEDLINE-PubMed), Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE. Articles were included if they were RCTs involving the interventions regarding the computer-guided impression, placement, and manufacturing process. The outcomes of interest include clinical and patient-reported outcomes and time efficiency. A meta-analysis was conducted to evaluate the time efficiency, pain severity, accuracy of implant placement, and postsurgery marginal bone level. RESULTS: A total of 39 and 25 articles were included in the qualitative and quantitative analysis, respectively. The results of the meta-analysis showed that significantly less time was spent performing the digital impression procedure than the conventional impression (P = .002). In addition, the average adjustment time of the final prosthesis was significantly less than the nondigital fabricated prosthesis (P = .0005). Computer-guided groups reported significantly lower painkiller consumption compared to control groups (P = .03). CONCLUSIONS: Digital impressions and CAD/CAM procedures are time-saving and provide stable and predictable outcomes. Moreover, computer-guided surgery can effectuate an accurate implant placement and less postsurgery discomfort.


Assuntos
Implantes Dentários , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Estados Unidos
3.
Qual Life Res ; 29(9): 2455-2464, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32307626

RESUMO

PURPOSE: It is not clear which factors hold more weight in predicting oral health-related quality of life (OHRQoL). Therefore, this study explored which component of factors (e.g., socio-economic status, clinical status or oral health behaviors, dental anxiety, oral health knowledge) has a better predictive value in different aspects (e.g., oral symptoms, functional limitations, social and emotional conditions) of adolescents' OHRQoL. METHODS: Participants were randomly selected from Grade Two (S2) students within 12 secondary schools in Hong Kong. The independent variables include the following : socio-economic (monthly family income, parents' educational background), oral health behaviors (the frequency of brushing and having snacks like chocolate or biscuits), and oral health-related factors (oral health knowledge, dental anxiety, dental caries and bleeding index). Adolescents' OHRQoL was evaluated using the 16-item Child Perception Questionnaire (CPQ11-14-ISF:16). Frequencies and means were used for data description. Different variables were analyzed as predictors of OHRQoL by multi-level linear regression analysis. RESULTS: 1207 adolescents (46.6% females) participated in this study. The mean total CPQ11-14-ISF:16 was 14.2 (9.8). Mean scores of oral symptoms, functional limitations, and emotional and social well-being were 4.4 (2.8), 4.2 (2.8), 3.2 (3.1), and 2.4 (2.7), respectively. In the final model, adolescents with poorer oral health knowledge, higher dental anxiety levels, brushed their teeth less than once a day and consumed chocolates or biscuits more regularly as reported by a statistically worse OHRQoL (p < 0.05). In addition, gingival bleeding was a predictor of the oral symptom domain (ß = 0.7, p = 0.027); the emotional well-being of adolescents whose father went to college had a better OHRQoL (ß = - 0.9, p = 0.014) and adolescents from the higher-income family had a statistically better social well-being (p = 0.015). CONCLUSION: Our study indicates that adolescents with poorer oral health knowledge, higher dental anxiety levels, brushing their teeth less than once a day, or having a daily consumption of chocolate or biscuits had statistically worse OHRQoL. These findings can provide guidance for future oral health promotion in improving OHRQoL among adolescents.


Assuntos
Ansiedade ao Tratamento Odontológico/psicologia , Comportamentos Relacionados com a Saúde/fisiologia , Saúde Bucal/normas , Qualidade de Vida/psicologia , Classe Social , Adolescente , Feminino , Humanos , Masculino
4.
BMC Public Health ; 20(1): 1755, 2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-33228621

RESUMO

BACKGROUND: A vicious cycle exists between dental anxiety, oral health behaviors and oral health status. Based on previous research, psychological factors of the Health Belief Model (HBM) are associated with oral health behaviors and oral health, and are likely involved in this cycle. However, little is known about the relationship between HBM factors and dental anxiety of adolescents. The purpose of this cross-sectional study was to investigate the relationship between health belief factors, oral health and dental anxiety based on the constructs of the HBM. METHODS: 1207 Grade 2 students from 12 secondary schools in Hong Kong were randomly selected and measured for the decayed, missing and filled permanent teeth (DMFT) index. Data for oral health behaviors, HBM constructs and dental anxiety were collected using questionnaires. The hierarchical entry of explanatory variables into logistic regression models estimating prevalence odds ratios (POR) were analyzed and 95% confidence intervals (95% CI) for DMFT and dental anxiety were generated. Path analysis was used to evaluate the appropriateness of the HBM as predictors for oral health behaviors, DMFT and dental anxiety. RESULTS: Based on the full model analysis, individuals with higher perceived susceptibility of oral diseases (POR: 1.33, 95% CI: 1.14-1.56) or girls or whose mother received higher education level were likelier to have a DMFT≥1, while those with higher perceived severity (POR: 1.31, 95%CI: 1.09-1.57), flossing weekly, DMFT≥1 or higher general anxiety level statistically increases the possibility of dental anxiety. The results from path analysis indicated that stronger perceived susceptibility, greater severity of oral diseases, less performing of oral health behaviors and a higher score of DMFT were directly related to increased dental anxiety level. Other HBM variables, such as perceived susceptibility, self-efficacy beliefs, cues to action and perceived barriers, might influence dental anxiety through oral health behaviors and caries status. CONCLUSIONS: Clarifying the propositional structures of the HBM may help the future design of theory-based interventions in reducing dental anxiety and preventing dental caries.


Assuntos
Ansiedade ao Tratamento Odontológico/epidemiologia , Modelo de Crenças de Saúde , Conhecimentos, Atitudes e Prática em Saúde , Saúde Bucal/estatística & dados numéricos , Adolescente , Estudos Transversais , Feminino , Hong Kong/epidemiologia , Humanos , Masculino , Instituições Acadêmicas , Estudantes/psicologia , Estudantes/estatística & dados numéricos , Inquéritos e Questionários
5.
BMC Public Health ; 20(1): 701, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32414375

RESUMO

BACKGROUND: Oral health belief is a prerequisite of changing oral health behaviors especially during adolescence. However, there is a paucity of well-established questionnaire for use among adolescents. This study aimed to develop and validate an instrument to evaluate adolescents' beliefs about oral health behaviors using health belief model. METHODS: A preliminary 43-item questionnaire was developed by an expert panel. Then the questionnaire was finalized by decreasing the number of items to 35 by analyzing the results from face validity and factor analysis from 421 Hong Kong secondary school students. The content validity were evaluated by a panel of 2 behavioral scientists, 2 dentists, 2 schoolteachers and 10 adolescents. The construct validity of the questionnaire was assessed by performing exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The Cronbach's alpha coefficient, item-total correlation and intraclass coefficient were used to test its reliability. In addition, to confirm its applicability, multiple regression analysis and path analysis were used to evaluate the possibility of HBM as predictors for oral health behaviors and oral hygiene status. RESULTS: The initial analysis extracted six factors that jointly accounted for 62.47% of the variance observed. Based on CFA, the final version of the questionnaire consisted of 35 items and the data of the final version fitted the model well. The Cronbach's alpha coefficient for the subscale (> 0.7), item-total correlations (0.47-0.91) and the intraclass coefficient (0.82-0.91) were all above acceptable thresholds. The results of multiple regression analysis and path analysis confirmed its ability to predict oral health behaviors and status. CONCLUSIONS: The present findings indicate satisfactory validity, reliability and applicability of the proposed Oral Health Behavior Questionnaire for Adolescents based on the Health Belief Model (OHBQAHBM) for measuring oral health beliefs of adolescents. This questionnaire can be used as an instrument to measure oral health beliefs and predict oral health behavior and oral hygiene status of adolescents.


Assuntos
Comportamentos Relacionados com a Saúde , Saúde Bucal/normas , Inquéritos e Questionários/normas , Adolescente , Análise Fatorial , Feminino , Hong Kong , Humanos , Masculino , Psicometria/métodos , Reprodutibilidade dos Testes
6.
Cell Biol Int ; 43(10): 1125-1136, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30022569

RESUMO

Integrin αv ß3 is a transmembrane integrin, which can initiate osteoclasts' attachment on bones, leading to downward signaling pathways and subsequent bone resorption. Different calcium concentrations have been reported to have an influence on the activation of integrin αv ß3 . To elucidate the regulatory mechanism of extracellular calcium concentrations on osteoclasts, a controlled micro flow plate (M04S) was utilized in the ONIX flow control system to observe the osteoclasts' adhesion and migration in different calcium concentration media. Fluorescent staining is conducted to show the distribution of integrin αv ß3 and cytoskeleton reorganization. In addition, western blots were performed to detect the expression of integrin αv ß3 and its downstream signaling pathways related to bone resorption. Also, real-time reverse-transcription polymerase chain reaction data of transcription co-activator (YAP/TAZ) and hydrolytic enzymes (the matrix metalloproteinase 9 and cathepsin K) are evaluated. Our findings suggest that osteoclasts' migration and adhesion is better promoted at 0.5 mM than 1.2 mM, which can be partly explained by the induced cytoskeleton organization via integrin αv ß3 /Rho GTPase. But the activation and nuclear localization of YAP/TAZ, and the secretion of hydrolytic enzymes were upregulated when the calcium concentration is at a higher level (1.2 mM). According to our study, there is a high possibility that the migration and attachment of osteoclasts and subsequent osteoclastic bone resorption are regulated over a specific range of extracellular calcium concentration.


Assuntos
Osso e Ossos , Cálcio/fisiologia , Osteoclastos , Animais , Reabsorção Óssea , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Adesão Celular , Movimento Celular , Células Cultivadas , Citoesqueleto/metabolismo , Integrina alfaVbeta3/metabolismo , Osteoclastos/metabolismo , Osteoclastos/patologia , Transdução de Sinais
7.
Biochem Biophys Res Commun ; 489(2): 179-186, 2017 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-28549584

RESUMO

OBJECTIVE: Previous studies found bone resorption and chondrocytes loss in mouse models of mid-palatal suture when given continuous compressive force, although chondrocytes response remained unknown. Herein, we design this study to determine how continuous compression force induces chondrocytes apoptosis. METHODS: Thirty C57BL/6 male mice (aged 6 weeks) were randomly assigned into controls (not ligated to a spring), blank controls (ligated with no compression) and the compression group (ligated with 20-g compression). After 4 d, palatal tissues were sampled and stained by TB and safranin-O. Tunel staining measured the percentage of apoptotic chondrocytes, and immunohistochemistry was performed to label apoptosis-associated proteins (e.g., Bcl-2, Bcl-xl, Bax, Bak, Bid, Bad, caspase-3, caspase-8 and caspase-9). Intergroup comparison was made by the rank sum test, and P < 0.05 was defined as statistical significance. RESULTS: After 7d of induction, TB and safranin-O staining revealed that the cartilage area in the compression group was significantly decreased, while the control group remained largely unaltered. Tunel staining showed that apoptotic cell numbers in the mid-palatal suture were significantly higher than the control group. Immunohistochemistry showed that mice in the compression group had significantly increased expression of caspase-3, caspase-9, Bad, Bak, Bax and Bid; However, caspase-8 remained unaltered. No expression of Bcl-2 and Bcl-xl was detected. CONCLUSIONS: Continuous compression force induces chondrocytes apoptosis in the mid-palatal suture. This process might be associated with the mitochondrial pathway.


Assuntos
Apoptose , Condrócitos/metabolismo , Condrócitos/patologia , Pressão/efeitos adversos , Suturas/efeitos adversos , Regulação para Cima , Animais , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/biossíntese , Caspase 3/biossíntese , Caspase 9/biossíntese , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenazinas , Cloreto de Tolônio , Proteína Killer-Antagonista Homóloga a bcl-2/biossíntese , Proteína X Associada a bcl-2/biossíntese , Proteína de Morte Celular Associada a bcl/biossíntese
8.
J Dent ; 146: 105064, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38768854

RESUMO

OBJECTIVES: This systematic review and meta-analysis aimed to assess the current performance of artificial intelligence (AI)-based methods for tooth segmentation in three-dimensional cone-beam computed tomography (CBCT) images, with a focus on their accuracy and efficiency compared to those of manual segmentation techniques. DATA: The data analyzed in this review consisted of a wide range of research studies utilizing AI algorithms for tooth segmentation in CBCT images. Meta-analysis was performed, focusing on the evaluation of the segmentation results using the dice similarity coefficient (DSC). SOURCES: PubMed, Embase, Scopus, Web of Science, and IEEE Explore were comprehensively searched to identify relevant studies. The initial search yielded 5642 entries, and subsequent screening and selection processes led to the inclusion of 35 studies in the systematic review. Among the various segmentation methods employed, convolutional neural networks, particularly the U-net model, are the most commonly utilized. The pooled effect of the DSC score for tooth segmentation was 0.95 (95 %CI 0.94 to 0.96). Furthermore, seven papers provided insights into the time required for segmentation, which ranged from 1.5 s to 3.4 min when utilizing AI techniques. CONCLUSIONS: AI models demonstrated favorable accuracy in automatically segmenting teeth from CBCT images while reducing the time required for the process. Nevertheless, correction methods for metal artifacts and tooth structure segmentation using different imaging modalities should be addressed in future studies. CLINICAL SIGNIFICANCE: AI algorithms have great potential for precise tooth measurements, orthodontic treatment planning, dental implant placement, and other dental procedures that require accurate tooth delineation. These advances have contributed to improved clinical outcomes and patient care in dental practice.


Assuntos
Algoritmos , Inteligência Artificial , Tomografia Computadorizada de Feixe Cônico , Imageamento Tridimensional , Dente , Humanos , Tomografia Computadorizada de Feixe Cônico/métodos , Dente/diagnóstico por imagem , Imageamento Tridimensional/métodos , Redes Neurais de Computação , Processamento de Imagem Assistida por Computador/métodos
9.
J Adolesc Health ; 70(2): 267-274, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34521576

RESUMO

PURPOSE: This study aimed to investigate the effects of a peer-led oral health intervention based on the Health Belief Model and the Social Cognitive Theory on improving oral health among Hong Kong adolescents. METHODS: The study adopted a cluster-randomized controlled trial design, and 1184 students in 12 schools were randomized to intervention or control groups. After baseline assessment, the intervention group received a peer-led theory-based oral health intervention, while the control group received booklets for oral health promotion. Self-reported brushing and flossing, Health Belief Model/Social Cognitive Theory constructs, and oral health-related quality of life (OHRQoL) were measured at baseline, 6 months, and 12 months, and dental plaque accumulation and caries status were measured at baseline and 12 months. The trial was registered at https://www.clinicaltrials.gov (NCT03694496). RESULTS: Brushing, flossing, and OHRQoL improved more in the experimental group than in the control group at the 6-month follow-up compared with baseline (p < .001). The mean gain score difference was .81 for brushing, .47 for flossing, and -2.51 for OHRQoL. At the 12-month follow-up, the mean gain score of brushing frequency, plaque index, caries status, and OHRQoL were .18, -.28, -.32, and -2.79, respectively, which all sustained the significant difference (p < .001). CONCLUSIONS: Our findings suggested that the Health Belief Model combined with Social Cognitive Theory in a peer-led intervention is effective to increase self-reported brushing frequency and improve oral hygiene status and OHRQoL among adolescents.


Assuntos
Saúde Bucal , Qualidade de Vida , Adolescente , Comportamentos Relacionados com a Saúde , Hong Kong , Humanos , Escovação Dentária
10.
Transl Behav Med ; 12(3): 423-432, 2022 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-34791503

RESUMO

Oral diseases are preventable through the building of good oral health behaviors. Theory-based behavior change was key to the efficacy of oral health promotion since conventional promotion strategies achieved only short-lived and limited improvements. The objective of the study was to investigate the efficacy of a peer-led oral health intervention based on the health belief model (HBM) and the social cognitive theory (SCT) on oral self-care behaviors among Hong Kong adolescents. One thousand one hundred and eighty-four adolescents in 12 schools participated and were randomly assigned to either intervention or control group, utilizing a cluster-randomized controlled trial design. Brushing/flossing frequency, HBM/SCT constructs, oral health knowledge, and dental anxiety were measured at baseline and 6-month follow-up. Changes in behaviors were assessed using mixed-effects model and the mediators of behavioral change were identified with parallel multiple mediation analysis. At 6 months, the intervention group showed a significant increase in the frequency of brushing and flossing compared with the control group. Self-efficacy was identified as mediator between treatment condition and behavioral changes of brushing and flossing. Combining theories of HBM and SCT is a promising avenue for efficacy in oral health behaviors. The effects were mediated through cognitive variables, which provided guidance for both theory and health intervention development.


Assuntos
Modelo de Crenças de Saúde , Saúde Bucal , Adolescente , Comportamentos Relacionados com a Saúde , Hong Kong , Humanos , Teoria Psicológica
11.
Psychol Health ; 36(7): 879-894, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-32755399

RESUMO

OBJECTIVE: To explore theory-guided randomized controlled trials aimed at improving adolescents' oral health and evaluate their effectiveness. DESIGN: Multiple library databases with search criteria for articles between 1990 and 2019. MAIN OUTCOME MEASURES: Searched references were coded and screened for theory-guided interventions for adolescent oral health. Characteristics of each study (study sample, adopted theory, outcome measures, length of follow-up and main findings) were extracted and the quality of the eligible trials assessed. Effect sizes for theory-guided interventions for different follow-up periods were analysed and compared with traditional oral health education. RESULTS: About 2135 results were uncovered, 64 were extracted for further screening, and 10 studies were eligible for inclusion. For plaque presence outcomes, no statistical difference was observed between theory-guided interventions and traditional interventions at 3 months (MD: -5.94, 95% CI: -16.39 to 4.51). When the duration of observation was extended to over one year, a significant reduction was found (SMD: -0.25, 95% CI: -0.46 to -0.04). CONCLUSION: Theory-guided interventions for improving oral hygiene status appear to be more effective than traditional interventions for adolescents in the long term. However, more comprehensive studies are required for validation to support the implementation and adoption of these programs in the clinical setting.


Assuntos
Saúde Bucal , Adolescente , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
12.
Patient Educ Couns ; 103(4): 725-733, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31813713

RESUMO

BACKGROUND: The aim of this review was to examine the effectiveness of behavioral interventions at different follow-up periods to improve adolescents' oral health. METHODS: CENTRAL, MEDLINE, EMBASE and other databases were systematically searched. Inclusion criteria were as follows: participants aged 10-19 years old, randomized controlled trials using behavioral interventions, outcome measurements including oral health knowledge, attitudes, practices, and oral health status. For each included study, behavior change techniques (BCT) were identified and the quality and risk of bias assessments obtained. PROSPERO reference: CRD42018090341. RESULTS: After searching and screening, 17 clinical trials were included in the systematic review. The most commonly used BCTs were behavior health link, information on consequences, and social comparisons. A significant reduction of plaque index was detected (SMD:-0.46; 95 % CI:-0.82∼-0.10) for 3 months and (SMD:-0.71; 95 % CI:-1.08∼-0.33) for 6 months. The reduction of gingival index after 6 months was also significant (SMD:-0.90; 95 % CI:-1.33∼-0.47). Oral health knowledge and oral health-related behavior were also improved after behavioral interventions. CONCLUSION: There is moderate evidence that behavioral interventions are effective in promoting oral health in adolescents. To establish more evidence-based conclusions, further research should focus on: quality control of interventions, full descriptions regarding the BCT, long-term follow-ups, and behavior change reinforcements. PRACTICAL VALUE: Given the need of early prevention of oral diseases, well-designed oral health promotion programme are needed to improve behavior and outcome of adolescents' oral health.


Assuntos
Terapia Comportamental , Saúde Bucal , Adolescente , Adulto , Criança , Comportamentos Relacionados com a Saúde , Promoção da Saúde , Humanos , Adulto Jovem
13.
Cell Biochem Biophys ; 74(4): 553-558, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27718044

RESUMO

Osteoclasts demineralize and resorb bone once they attach to its surface. However, it's still unclear how the osteoclasts choose the specific sites for their attachments. It is postulated in this article that the decreased extracellular free ionized calcium concentration (Ca2+[e]) can provide a microenvironment for osteoclasts to recognize and then initiate the attachment process. The osteoclasts initially attach to the bone surface via integrating its integrin αvß3 and RGD containing ligands in bone matrix. Through the interaction with RGD-containing ligand, the integrin αvß3 forms carboxylate oxygen noncovalent, which is further stabilized by accompanied electrostatic interaction between the Ca2+ and the ß3 subunit. There are two types of cation-binding sites on the ß3 subunit: the high affinity Ca2+ binding site ("LC" site) that activates the osteoclasts by promoting the combination; the low affinity Ca2+ binding site ("I" site, also named ADMIDAS) that deactivates the osteoclasts by dissociating the combination and it can override the "LC" site's positive effect on osteoclasts when necessary. Normally the Ca2+ concentration of bone extracellular fluid is maintained within a normal range by osteocytes, keeping the "I" sites activated. When the osteocytes' function stalls and the ambient Ca2+ concentration falls below the affinity discrimination threshold between the "I" site and the "LC" site, the "LC" site's promoting function starts to out compete the "I" site in its inhibitory effect, in which case the inactive integrin αvß3 turns into an extended active form and the osteoclasts start to attach, signifying the initiation of bone resorption.


Assuntos
Osso e Ossos/metabolismo , Cálcio/metabolismo , Adesão Celular/fisiologia , Osteoclastos/citologia , Sítios de Ligação , Osso e Ossos/química , Matriz Extracelular/metabolismo , Humanos , Integrina alfaVbeta3/química , Integrina alfaVbeta3/metabolismo , Ligantes , Modelos Teóricos , Oligopeptídeos/metabolismo , Osteoclastos/metabolismo
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