Dental pulp cells cocultured with macrophages aggravate the inflammatory conditions stimulated by LPS.

BACKGROUND: Pulp inflammation is complex interactions between different types of cells and cytokines. To mimic the interactions of different types of cells in inflamed dental pulp tissues, dental pulp cells (DPCs) were cocultured with different ratios of macrophages (THP-1) or LPS treatment. METHODS: DPCs were cocultured with various ratios of THP-1, then photographed cell morphology and determined cell viability by MTT assay at preset times. Total RNA was also extracted to measure the inflammation marker-IL-6 and IL-8 expressions by RT-Q-PCR. The DPCs and THP-1 were treated with 0.01 - 1µg/ml lipopolysaccharide (LPS) and extract RNA at preset times, and detected IL-6 and IL-8 expression. DPCs were cocultured with various ratios of THP-1 with 0.1 µg/mL LPS, and detected IL-6 and IL-8 expression after 24 and 48 h. The data were analyzed by unpaired t-test or Mann-Whitney test. Differences were considered statistically significant when p < 0.05. RESULTS: THP-1 and DPCs coculture models did not suppress the viability of DPCs and THP-1. Cocultured with various ratios of THP-1 could increase IL-6 and IL-8 expressions of DPCs (p = 0.0056 - p < 0.0001). The expressions of IL-6 and IL-8 were stronger in higher ratio groups (p = 0.0062 - p < 0.0001). LPS treatment also induced IL-6 and IL-8 expressions of DPCs and THP-1 (p = 0.0179 - p < 0.0001 and p = 0.0189 - p < 0.0001, separately). Under the presence of 0.1 µg/mL LPS, DPCs cocultured with THP-1 for 24 h also enhanced IL-6 and IL-8 expression (p = 0.0022). After cocultured with a higher ratio of THP-1 for 48 h, IL-6 and IL-8 expressions were even stronger in the presence of LPS (p = 0.0260). CONCLUSIONS: Coculturing dental pulp cells and macrophages under LPS treatment aggravate the inflammatory process. The responses of our models were more severe than traditional inflamed dental models and better represented what happened in the real dental pulp. Utilizing our models to explore the repair and regeneration in endodontics will be future goals.

Biodentine but not MTA induce DSPP expression of dental pulp cells with different severity of LPS-induced inflammation.

OBJECTIVES: To explore the inflammatory and differentiation response in inflamed dental pulp cells (DPCs) induced by lipopolysaccharide (LPS) under different conditions with Biodentine and mineral trioxide aggregate (MTA) treatment. MATERIALS AND METHODS: DPCs were treated with 0.001-1 µg/mL LPS for different periods to induce inflammation. Normal and inflamed DPCs were further treated with 0.14 mg/mL Biodentine or 0.13 mg/mL MTA for different periods. mRNA expression level of IL-6, IL-8 and ALP were analysed by qPCR. DSPP protein expression was detected by western blot. The data were analysed by the Mann-Whitney test, unpaired t test or two-way ANOVA. RESULTS: After treatment for different times and with different concentrations of LPS, different severity of pulp inflammation was revealed by the expressions of IL-6 and IL-8. Higher concentrations of LPS induced higher IL-6 and IL-8 expressions, and these expressions first increased and then decreased (p < 0.0001). At 96 and 192 h, Biodentine significantly suppressed IL-6 expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine suppressed ALP expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine induced DSPP expressions in both normal and inflamed DPCs (p < 0.05). CONCLUSION: Biodentine enhanced more DSPP differentiation of both normal and inflamed DPCs under different treatment durations than MTA. CLINICAL RELEVANCE: The prognosis of vital pulp therapy may depend on the severity of pulp inflammation which is difficult to be determined in clinical settings. Therefore, Biodentine may enhance odontogenic differentiation in different severity of pulp inflammation imply its clinical indications.

A scoping review of intervention components of school-based oral health-related behavioural interventions using the Theoretical Domains Framework.

The aim of this study was to review the intervention components of school-based oral health-related behavioural interventions using the Theoretical Domains Framework (TDF). We identified relevant papers from the review of Cooper et al., and these papers came from both the original inclusion and exclusion article lists. We also modified and updated their search strategies (2013 - April 2019). The 53 included papers reported on 79 interventions (experimental groups = 57 interventions, control groups = 22 interventions). Most of the papers used three to nine domains (average = 5.6) in their experimental interventions, and the most commonly used domains were 'knowledge,' 'skills,' 'social influences,' and 'environmental context and resources.' Considering the complexity of intervention components in one programme, there is no one specific domain or domain set that can determine the success of behavioural interventions. The design of future programmes should be guided by a complex intervention methodology. However, the best combination set might not exist, and the choice of domains should depend on local context or resources. This study can be used as a resource for identifying previous papers, which have used the same domains.

Translation and validation of modified dental anxiety scale based on adult Taiwan population.

BACKGROUND: Dental anxiety is associated with negative experiences of dental treatment and dental-visiting behavior. The Modified Dental Anxiety Scale (MDAS) is widely used for assessing dental anxiety. The study aims to establish the psychometric properties of a Chinese version of the MDAS based on the Taiwan sample (i.e., T-MDAS). METHODS: The T-MDAS and dental-visiting behavior and experience were assessed for 402 adult subjects recruited from community and clinical sites. The following psychometric properties were assessed: (a) internal consistency, (b) temporal stability, (c) criterion-related validity (i.e., the association with the score of Index of Dental Anxiety and Fear, IDAF-4C), (d) discrimination validity (i.e., the difference in scores between the subjects with and without a habit of a regular dental visit, and (e) the construct validity from a confirmatory factor analysis (CFA). RESULTS: The T-MDAS showed good internal consistency (Cronbach's α = 0.88) and temporal stability (ρ = 0.69, p < 0.001). The score was significantly correlated with the score of the IDAF-4C (ρ = 0.76, p < 0.001) and differed between subjects who regularly visited a dentist or not, supporting good criterion-related validity and discrimination validity. Results from CFA supports good construct validity. Furthermore, higher dental anxiety was related to the lack of a regular dental visit, feeling pain during treatment, and feeling insufficient skills and empathy of dentists. A higher proportion of high-dental anxiety subjects in female subjects (8.5%), compared to male subjects (5.0%), was noted. CONCLUSIONS: The T-MDAS is a valid tool for assessing adult dental anxiety. The score is highly associated with dental-visiting behavior and experience of dental patients.

Portland cement induces human periodontal ligament cells to differentiate by upregulating miR-146a.

BACKGROUND/PURPOSE: Bioaggregates such as Portland cement (PC) can be an economical alternative for mineral trioxide aggregate (MTA) with additional benefit of less discoloration. MTA has been known to induce differentiations of several dental cells. MicroRNAs are important regulators of biological processes, including differentiation, physiologic homeostasis, and disease progression. This study is to explore how PC enhances the differentiation of periodontal ligament (PDL) cells in microRNAs level. METHODS: PDL cells were cultured in a regular PC- or MTA-conditioned medium or an osteoinduction medium (OIM). Alizarin red staining was used to evaluate the extent of mineralization. Transfection of microRNA mimics induced exogenous miR-31 and miR-146a expression. The expression of microRNAs and differentiation markers was assayed using reverse-transcriptase polymerase chain reaction. RESULTS: PC enhanced the mineralization of PDL cells in a dose-dependent manner in the OIM. Exogenous miR-31 and miR-146a expression upregulated alkaline phosphatase (ALP), bone morphogenic protein (BMP), and dentin matrix protein 1 (DMP1) expression. However, miR-31 and miR-146a modulates cementum protein 1 (CEMP1) expression in different ways. PC also enhanced ALP and BMP but attenuated CEMP1 in the OIM. Although the OIM or PC treatment upregulated miR-21, miR-29b, and miR-146a, only miR-146a was able to be induced by PC in combination with OIM. CONCLUSION: This study demonstrated that PC enhances the differentiation of PDL cells, especially osteogenic through miR-146a upregulation. In order to control the ankylosis after regenerative endodontics with the usage of bioaggregates, further investigations to explore these differentiation mechanisms in the miRNA level may be needed.

A qualitative study of patients' views of techniques to reduce dental anxiety.

OBJECTIVES: To explore the fear/anxiety inducing triggers associated with dental treatment, and what dentally anxious adults would like from their dental encounter. METHODS: Two focus-groups and three interviews with fourteen dentally-anxious people were conducted in this qualitative study. All discussions were tape-recorded and transcribed verbatim. Content was categorised by common characteristics to identify underlying themes using thematic analysis. RESULTS: Four themes were identified to bring general meaning within the content: 1. Preparedness, 2. Teamwork, 3. Reinforced trust, 4. Tailored treatment plan. CONCLUSIONS: Preparatory information may need to be tailored and comprehensive, yet dissociative and reassuring. Dentally-anxious people might want a sense of control and shared-decision making. They may not want dentists to understate the treatment procedures and risks to make them feel better temporarily. CLINICAL SIGNIFICANCE: Dental anxiety affects between 10 and 60% of the population. Participants in this study suggested different ways the dental team could help their anxiety. Therefore, it is key for whole dental team to find out what could be done to help dentally anxious patients.

Lipopolysaccharide induces the migration of human dental pulp cells by up-regulating miR-146a.

INTRODUCTION: MicroRNAs are small noncoding RNAs that play crucial roles in regulating normal and pathologic functions. Bacterial lipopolysaccharide (LPS) is one of the key regulators of pulpal pathogenesis. This study investigated how LPS regulates microRNA expression and affects the phenotype of human dental pulp cells (DPCs). METHODS: Primary DPCs were established and immortalized to achieve immortalized DPCs (I-DPCs). DPCs and I-DPCs were treated with LPS and examined to identify changes in microRNA expression, cell proliferation, and cell migration. Quantitative reverse-transcriptase polymerase chain reaction was used to detect changes in gene expression. Exogenous miR-146a expression was performed transfection with pre-mir-146a mimic. Knockdown of interleukin receptor-associated kinase (IRAK1) and tumor necrosis factor receptor-associated factor 6 (TRAF6) expression was performed by small interference oligonucleotide transfection. Western blot analysis was used to detect changes in the expression of the IRAK1 and TRAF6 proteins. RESULTS: The differentiation of DPCs was induced by osteogenic medium. I-DPCs had a higher level of human telomerase reverse transcriptase gene than the parental DPCs. Up-regulation of miR-146a expression and an increase in migration was induced by LPS treatment of DPCs and I-DPCs. Exogenous miR-146a expression increased the migration of DPCs and I-DPCs and down-regulated the expression of IRAK1 and TRAF6. Knockdown of IRAK1 and/or TRAF6 increased the migration of DPCs. CONCLUSIONS: The results suggested that LPS is able to increase the migration of DPCs by modulating the miR-146a-TRAF6/IRAK1 regulatory cascade.