Displaying all 11 publications

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  1. Yap AU, Ong JE, Yahya NA
    J Mech Behav Biomed Mater, 2021 01;113:104120.
    PMID: 33086137 DOI: 10.1016/j.jmbbm.2020.104120
    OBJECTIVES: This study determined the effects of self-adhesive resin coatings on viscoelastic properties of highly viscous glass ionomer cements (HVGICs) using dynamic mechanical analysis.

    MATERIALS AND METHODS: The HVGICs evaluated were Zirconomer [ZR] (Shofu), Equia Forte [EQ] (GC) and Riva [RV] (SDI). Sixty specimens (12mm x 2mm x 2mm) of each material were fabricated using customized Teflon molds. After initial set, the specimens were removed from their molds, finished, measured and randomly divided into 3 groups of 20. Half the specimens in each group were left uncoated while the remaining half was covered with the respective manufacturers' resin coating. The specimens were subsequently conditioned in distilled water, artificial saliva or citric acid at 37°C for 7 days. The uncoated and coated specimens (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C with a frequency of 0.1 to 10Hz. Storage modulus, loss modulus and loss tangent data were subjected to normality testing and statistical analysis using one-way ANOVA/Scheffe's post-hoc test and Ttest at significance level p<0.05.

    RESULTS: Mean storage modulus ranged from 1.39 ± 0.36 to 10.80 ± 0.86 GPa while mean loss modulus varied from 0.13 ± 0.03 to 0.70 ± 0.14 GPa after conditioning in the different mediums. Values for loss tangent ranged from 39.4 ± 7.75 to 213.2 ± 20.11 (x10 -3 ). Significant differences in visco-elastic properties were observed between mediums and materials. When conditioned in distilled water and artificial saliva,storage modulus was significantly improved when ZR, EQ and RV were uncoated. Significantly higher values were, however, observed with resin coating when the materials were exposed to citric acid.

    CONCLUSION: The visco-elastic properties of HVGICs were influenced by both resin coating and chemical environment.

  2. Song YL, Yap AU, Türp JC
    J Oral Rehabil, 2018 Dec;45(12):1007-1015.
    PMID: 30125394 DOI: 10.1111/joor.12704
    The aim of this systematic review (SR) was to determine the association between temporomandibular disorders (TMDs) and pubertal development. Due to the inadequacy of the conventional PICO (Population, Interventions, Comparisons and Outcome) format used for intervention-based SRs, the Joanna Briggs Institute's guidelines for synthesising evidence related to associations with a focus on aetiology were adopted. A search of the PubMed and LIVIVO databases covering the period from January 1980 to May 2018 yielded four publications, which fulfilled the inclusion criteria. Analysis of articles based on the Pubertal Development Scale showed that TMD prevalence increases with pubertal development. Although no sex difference in TMD prevalence and diagnosis was observed, more females reported TMD anamnestic variables, including accounts of temporomandibular pain during pubertal maturity. The higher prevalence of depression and somatisation during pubertal development may contribute to more TMD symptom reporting in females. More prospective studies incorporating standardised methods for diagnosing TMDs and detecting comorbid psychosocial and somatic problems are desired to further elucidate the relationship between TMDs and pubertal development.
  3. Khoo SP, Yap AU, Chan YH, Bulgiba AM
    J Orofac Pain, 2008;22(2):131-8.
    PMID: 18548842
    To develop a Malay-language version of the Axis II Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) through a formal translation/back-translation process and to summarize available data about the psychometric properties of the translated scales.
  4. Eweis AH, Yap AU, Yahya NA
    J Mech Behav Biomed Mater, 2017 10;74:183-188.
    PMID: 28605721 DOI: 10.1016/j.jmbbm.2017.06.004
    This study investigated the effect of food simulating liquids on visco-elastic properties of bulk-fill restoratives using dynamic mechanical analysis. One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2mm) were fabricated using customized stainless steel molds. The specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37°C: air (control), artificial saliva (SAGF), distilled water, 0.02N citric acid, heptane, 50% ethanol-water solution. Specimens were assessed using dynamic mechanical testing in flexural three-point bending mode and their respective mediums at 37°C and a frequency range of 0.1-10Hz. The distance between the supports were fixed at 10mm and an axial load of 5N was employed. Data for elastic modulus, viscous modulus and loss tangent were subjected to ANOVA/Tukey's tests at significance level p < 0.05. Significant differences in visco-elastic properties were observed between materials and mediums. Apart from bulk-fill giomer, elastic modulus was the highest after conditioning in heptane. No apparent trends were noted for viscous modulus. Generally, loss tangent was the highest after conditioning in ethanol. The effect of food-simulating liquids on the visco-elastic properties of bulk-fill composites was material and medium dependent.
  5. Ong J, Yap AU, Abdul Aziz A, Yahya NA
    Oper Dent, 2023 Jan 01;48(1):90-97.
    PMID: 36445974 DOI: 10.2341/21-202-L
    This study investigated the effects of environmental pH on the flexural properties of ion-releasing restorative materials (IRMs), including giomer (Beautifil-Bulk Restorative - BB), alkasite (Cention N - CN), bioactive composite (Activa - AB) and resin-modified glass ionomer (Riva Light Cure -RV) restoratives. A bio-inert resin-based composite (Filtek Bulk-fill Posterior - FB) served as the control. Stainless steel molds were used to fabricate 40 beam-shaped specimens (12mm × 2mm × 2mm) for each material. The specimens were finished, measured, and randomly distributed into four groups (n=10) and immersed in aqueous solutions of pH 3.0, pH 5.0, pH 6.8, and pH 10.0 at 37°C for 28 days. Specimens were then subjected to a uniaxial three-point bending flexural test with a load cell of 5 KN and a fixed deformation rate of 0.5 mm/min until fracture occurred. Flexural modulus and strength were statistically analyzed using analysis of variance/Dunnet T3's test (p=0.05). Mean flexural modulus varied from (2.40±0.41 to 9.65±1.21 GPa), while mean flexural strength ranged from (21.56±2.78 to 163.86±13.13 MPa). Significant differences in flexural properties were observed among the various pH values and materials. All materials immersed in artificial saliva (pH 6.8) presented the highest flexural properties, except AB. The flexural strength of AB was significantly better when exposed to acidic environments. FB had better flexural properties than IRMs after exposure to a range of environmental pH values.
  6. Ibrahim H, Aziz AA, Yahya NA, Yap AU
    Oper Dent, 2024 Mar 01;49(2):178-188.
    PMID: 38196082 DOI: 10.2341/23-038-L
    This study examined the influence of cariogenic environments on the surface roughness of ion-releasing restorative materials (IRMs). Custom-made stainless steel molds with holes of 5 mm × 2mm were used to fabricate 60 disc-shaped specimens of each of the following materials: Activa Bioactive (AV), Beautifil Bulk Restorative (BB), Cention N (Bulk-fill) (CN), and Filtek Z350XT (FZ) (Control). Baseline surface roughness (Ra) measurements were obtained using an optical 3D measurement machine (Alicona Imaging GmbH, Graz, Austria). The specimens were then randomly divided into five subgroups (n=12) and exposed to 10 ml of the following mediums at 37°C: distilled water (DW), demineralization solution (DM), remineralization solution (RM), pH cycling (PC) and air (AR) (control). Ra measurements were again recorded after one week and one month, followed by statistical evaluations with two-way analysis of variance (ANOVA) to determine interactions between materials and mediums. One-way ANOVA and post hoc Games Howell tests were performed for intergroup comparisons at a significance level of 0.05. Mean Ra values ranged from 0.085 ± 0.004 (µm) to 0.198 ± 0.001 µm for the various material-medium combinations. All IRMs showed significant differences in Ra values after exposure to the aqueous mediums. The smoothest surfaces were observed in the AR for all materials. When comparing materials, AV presented the roughest surfaces for all mediums. All IRM materials showed increased surface roughness over time in all cariogenic environments but were below the threshold value for bacterial adhesion, except for AV 1-month post immersion with pH cycling. Therefore, besides AV, the surface roughness of IRMs did not deteriorate to an extent that it is clinically relevant.
  7. Eweis AH, Yap AU, Yahya NA
    Saudi Dent J, 2018 Jul;30(3):232-239.
    PMID: 29942108 DOI: 10.1016/j.sdentj.2018.04.002
    OBJECTIVE: This study investigated the effect of dietary solvents on flexural strength and modulus of bulk-fill composites.

    MATERIALS AND METHODS: One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2 mm) were fabricated using customized stainless steel molds. Specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37 °C: air (control), artificial saliva (SAGF), distilled water, 0.02 N citric acid, heptane, 50% ethanol-water solution. After conditioning, the specimens were rinsed, blotted dry, measured and subjected to flexural testing using a universal testing machine. Representative SEM images of the intact surfaces were obtained to appraise the degradation mechanism by dietary solvents. Data was subjected to statistical analysis using ANOVA/Tukey's tests at significance level p 

  8. Tahir MKAM, Kadir K, Apipi M, Ismail SM, Yusof ZYM, Yap AU
    J Oral Facial Pain Headache, 2020 12 9;34(4):323-330.
    PMID: 33290438 DOI: 10.11607/ofph.2624
    AIMS: To develop the Malay DC/TMD through a formal cross-cultural adaptation (CCA) process for use in non-English speaking populations and to determine the reliability and validity of the Malay Graded Chronic Pain Scale (M-GCPS) and Malay Jaw Functional Limitation Scale (M-JFLS).

    METHODS: The English DC/TMD was translated into the Malay language using the forward-backward translation procedures specified in the INfORM guideline. The initial Malay instrument was pre-tested, and any discrepancies were identified and reconciled before producing the final Malay DC/TMD. Psychometric properties of the M-GCPS and M-JFLS were evaluated using a convenience sample of 252 subjects and were assessed using internal consistency and test-retest reliability, as well as face, content, concurrent, and construct validity testing. Internal consistency was assessed using Cronbach's alpha, while test-retest reliability was examined using intraclass correlation coefficient (ICC). Concurrent and construct validity of both domains were performed using Spearman ρ correlation test. In addition, construct and discriminant validity were appraised using Kruskal-Wallis and Mann-Whitney U tests, respectively.

    RESULTS: Cronbach's alpha values for the M-GCPS and M-JFLS were 0.95 and 0.97, respectively. The ICC was 0.98 for the M-GCPS and 0.99 for M-JFLS. The majority of the tested associations for both domains were found to be statistically significant, with good positive correlations.

    CONCLUSION: The M-GCPS and M-JFLS were found to be reproducible and valid. The Malay DC/TMD shows potential for use among Malay-speaking adults.

  9. Alyessary AS, Yap AU, Othman SA, Rahman MT, Al-Namnam NM, Radzi Z
    J Orofac Orthop, 2018 May;79(3):169-179.
    PMID: 29644389 DOI: 10.1007/s00056-018-0134-4
    OBJECTIVE: Accelerated bone-borne expansion protocols on sutural separation and sutural bone formation were evaluated via histomorphometry and immunohistochemistry to determine the optimal initial activation without disruption of bone formation.

    MATERIALS AND METHODS: Sixteen New Zealand white rabbits were randomly divided into four groups. Modified Hyrax expanders were placed across the midsagittal sutures and secured with miniscrew implants with the following activations: group 1 (control), 0.5 mm expansion/day for 12 days; group 2, 1 mm instant expansion followed by 0.5 mm expansion/day for 10 days; group 3, 2.5 mm instant expansion followed by 0.5 mm expansion/day for 7 days; and group 4, 4 mm instant expansion followed by 0.5 mm expansion/day for 4 days. After 6 weeks, sutural expansion and new bone formation were evaluated histomorphometrically. Statistical analysis was performed using Kruskal-Wallis/Mann-Whitney U tests and Spearman's rho correlation (p 

  10. Asghar M, Omar RA, Yahya R, Yap AU, Shaikh MS
    J Esthet Restor Dent, 2023 Mar;35(2):322-332.
    PMID: 36628650 DOI: 10.1111/jerd.13013
    OBJECTIVE: To the effectiveness of different strategies to overcome silver diamine fluoride (SDF)-mediated tooth staining.

    MATERIALS AND METHODS: Four online databases (PubMed, ScienceDirect, Scopus, and Web of Science) were searched using different MeSH terms and Boolean Operators to retrieve the articles (until June 2021), followed by a hand-search of the reference list of the included articles. All full-text, original studies in English that evaluated SDF staining and at least one SDF modification/alternative were included.

    RESULTS: Among the assessed studies, nine studies explored the stain-minimization effect of potassium iodide (KI) post-application following SDF treatment. Among these, eight concluded that KI application after SDF treatment significantly reduced tooth staining, while one showed marginal staining following glass ionomer restoration of the SDF-treated dentine. Additionally, one study applied potassium fluoride (KF) and silver nitrate (AgNO3 ) concurrently to mitigate SDF-mediated staining. One study compared SDF staining with polyethylene glycol (PEG)-coated nanoparticles containing sodium fluoride (NaF), and another used nanosilver fluoride (NSF) for staining comparison with SDF.

    CONCLUSIONS: Within the limitations of this study, the addition of different materials to SDF has proven to be a beneficial strategy for overcoming tooth staining associated with SDF. Future studies are warranted, particularly clinical trials, to validate these findings.

    CLINICAL SIGNIFICANCE: SDF-mediated tooth staining is a serious concern that limits its clinical use. A review of various strategies to overcome this problem will help clinicians enhance its clinical use and patient acceptance.

  11. Yap AU, Apipi M, Ismail SM, Yusof ZYM, Kadir K
    Cranio, 2022 Apr 06.
    PMID: 35384792 DOI: 10.1080/08869634.2022.2059130
    OBJECTIVE: This study translated/cross-culturally adapted the Fonseca Anamnestic Index (FAI) for temporomandibular disorders (TMDs) into Malay and psychometrically tested the Malay-FAI (FAI-M).

    METHODS: The FAI-M was created according to international guidelines. Internal consistency/test-retest reliability were assessed with Cronbach's alpha/intra-class correlation (ICC) coefficients. Construct and convergent validity were appraised by relating the FAI-M to the Global Oral Health (GOH) questionnaire and Short-form Oral Health Impact Profile (S-OHIP) using Kruskal-Wallis and Spearman's rho correlation (α = 0.05).

    RESULTS: Of the 243 participants enrolled, 54.7% (n = 133) had no TMDs, while TMDs were present in 45.3% (n = 110). The FAI-M presented very good internal consistency (α = 0.90) and test-retest reliability (ICC = 0.99). Theoretically predicted FAI-M score patterns matched the GOH categories, and strong correlations were discerned between FAI-M and S-OHIP (rs = 0.71).

    CONCLUSION: The FAI-M exhibited good psychometric properties and can be applied in Malay-speaking populations.

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