Displaying publications 1 - 20 of 39 in total

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  1. Tan SK, Leung WK, Tang ATH, Zwahlen RA
    J Craniomaxillofac Surg, 2020 Dec;48(12):1106-1111.
    PMID: 33041190 DOI: 10.1016/j.jcms.2020.09.012
    PURPOSE: To assess and compare the changes in satisfaction with facial appearance and psycho-social well-being in dento-skeletal class II and III patients after orthognathic surgery with the FACE-Q among Hong Kong Chinese.

    METHODS: The questionnaires for thirteen orthognathic-relevant FACE-Q scales, translated into Cantonese and validated, were administered to Hong Kong Chinese patients before and after orthognathic surgery in the short- and long-term, respectively. The assessed scales were categorized into four main domains: satisfaction with facial appearance, quality of life, patient's experience of care, and adverse effects.

    RESULTS: Generally, highly significant (p 

  2. Tan SK, Leung WK, Tang ATH, Zwahlen RA
    PLoS One, 2017;12(7):e0181146.
    PMID: 28749983 DOI: 10.1371/journal.pone.0181146
    BACKGROUND: Mandibular advancement surgery may positively affect pharyngeal airways and therefore potentially beneficial to obstructive sleep apnea (OSA).

    OBJECTIVE: To collect evidence from published systematic reviews that have evaluated pharyngeal airway changes related to mandibular advancement with or without maxillary procedures.

    METHODOLOGY: PubMed, EMBASE, Web of Science, and Cochrane Library were searched without limiting language or timeline. Eligible systematic reviews evaluating changes in pharyngeal airway dimensions and respiratory parameters after mandibular advancement with or without maxillary surgery were identified and included.

    RESULTS: This overview has included eleven systematic reviews. Maxillomandibular advancement (MMA) increases linear, cross-sectional plane and volumetric measurements of pharyngeal airways significantly (p<0.0001), while reducing the apnea-hypopnea index (AHI) and the respiratory disturbance index (RDI) significantly (p<0.0001). Two systematic reviews included primary studies that have evaluated single-jaw mandibular advancement, but did not discuss their effect onto pharyngeal airways. Based on the included primary studies of those systematic reviews, single-jaw mandibular advancement was reported to significantly increase pharyngeal airway dimensions (p<0.05); however, conclusive long-term results were lacking.

    CONCLUSION: MMA increases pharyngeal airway dimensions and is beneficial to patients suffering from OSA. However, more evidence is still needed to draw definite conclusion related to the effect of single-jaw mandibular advancement osteotomies on pharyngeal airways.

  3. Tan SK, Tang ATH, Leung WK, Zwahlen RA
    J Stomatol Oral Maxillofac Surg, 2018 Dec;119(6):461-468.
    PMID: 30099221 DOI: 10.1016/j.jormas.2018.07.004
    PURPOSE: To investigate short- and long-term post-surgical three-dimensional changes of pharyngeal airway morphology and hyoid bone position in dento-skeletal class II deformity patients after two-jaw surgery with segmentation.

    METHODS: Relations between skeletal movement, hyoid bone position and three-dimensional pharyngeal airway changes were retrospectively analyzed on pre- and post-surgical CBCTs in dento-skeletal class II patients who underwent orthognathic two-jaw surgery with segmentation.

    RESULTS: While long-term significant reductions in length (P= 0.003), surface area (P= 0.042) and volume (P= 0.004) were found in the nasopharynx, the highly significant increases in oropharyngeal airway length, surface area, volume and the minimal cross-sectional area (P 

  4. Tan SK, Tang ATH, Leung WK, Zwahlen RA
    J Craniofac Surg, 2019 Mar 28.
    PMID: 30946225 DOI: 10.1097/SCS.0000000000005351
    PURPOSE: To investigate short- and long-term three-dimensional changes of pharyngeal airway morphology and hyoid bone position in dento-skeletal class III deformity patients after 2-jaw orthognathic surgery with segmentation.

    METHODS: A retrospective analysis has been performed on patients with dento-skeletal class III deformity who had undergone orthognathic 2-jaw surgery with segmentations, presenting both pre- and post-surgical cone-beam computed tomographys. Three-dimensional skeletal movements, pharyngeal airway changes and hyoid bone position were measured and correlated.

    RESULTS: The mean short term postsurgical review period for all included 47 patients was 5.8 ± 2.2 months. Thirteen patients among them provided a mean long term period of 26.4 ± 3.4 months. The mean postsurgical maxillary movement was 2.29 ± 2.49 mm in vertical, 2.02 ± 3.45 mm in horizontal direction, respectively, while the mandibular movement was 6.49 ± 4.58 mm in vertical, and -5.85 ± 6.13 mm in horizontal direction. In short-term, the vertical length of nasopharynx was found to be reduced (P = 0.005) but increased for the oropharynx (P  0.05) detected between patients with and without genioplasty advancement.

    CONCLUSION: Two-jaw orthognathic surgery in dento-skeletal class III patients led to a statistically non-significant reduction of the post-surgical airway volume in both short- and long-term. Although the post-surgical oropharyneal minimum cross-sectional area was decreased significantly in the short term, this finding did not persist in the long term.

  5. Tan SK, Leung WK, Tang ATH, Zwahlen RA
    Am J Orthod Dentofacial Orthop, 2022 Feb;161(2):e105-e113.
    PMID: 34531091 DOI: 10.1016/j.ajodo.2021.01.024
    INTRODUCTION: This study was conducted to investigate and compare esthetic perceptions of different facial profiles among Hong Kong Chinese laypersons and patients scheduled for orthognathic treatment.

    METHODS: Two sets of 3-dimensional facial photographs (1 male and 1 female) each comprised 7 images that showed different dentoskeletal relations (ie, Class I, bimaxillary protrusion, bimaxillary retrusion, maxillary protrusion, maxillary retrusion, mandibular protrusion, and mandibular retrusion). The sets of photographs were shown to 101 laypersons (age, 28.87 ± 6.22 years) and 60 patients seeking orthognathic treatment (age, 27.12 ± 6.07 years). They rated their esthetic perceptions of the photographs on the basis of a 100 mm visual analog scale (VAS) from 0 (very unattractive) to 100 (very attractive).

    RESULTS: The dentoskeletal Class I facial profile was ranked as the most attractive profile. Female orthognathic judges selected the retrusive maxilla while male orthognathic judges and male and female laypersons ranked the mandibular protrusion profile as the least attractive profile for both females and males. A bimaxillary protrusive female profile was viewed as more attractive by the orthognathic male (P = 0.006) and female (P = 0.006) judges, compared with female layperson judges. After adjustment for age, no statistically significant interaction between sex and judges (P >0.10) for all VAS scores were detected. For the female bimaxillary protrusive profile, orthognathic patient judges assigned a mean VAS score of 9.174 points higher than layperson judges (95% confidence interval, 3.11-15.24; P = 0.003).

    CONCLUSION: Dentoskeletal Class I facial profile was generally considered the most attractive profile in both sexes; male and female orthognathic patients preferred a bimaxillary protrusive female profile. A concave facial profile was perceived as least attractive in both sexes.

  6. Tan SK, Leung WK, Tang ATH, Zwahlen RA
    PLoS One, 2017;12(10):e0185951.
    PMID: 29016682 DOI: 10.1371/journal.pone.0185951
    BACKGROUND: Mandibular setback osteotomies potentially lead to narrowing of the pharyngeal airways, subsequently resulting in post-surgical obstructive sleep apnea (OSA).

    OBJECTIVE: To summarize current evidence from systematic reviews that has evaluated pharyngeal airway changes after mandibular setback with or without concomitant upper jaw osteotomies.

    METHODOLOGY: PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched with no restriction of language or date. Systematic reviews studying changes in pharyngeal airway dimensions and respiratory parameters after mandibular setback with or without concomitant upper jaw osteotomies have been identified, screened for eligibility, included and analyzed in this study.

    RESULTS: Six systematic reviews have been included. While isolated mandibular setback osteotomies result in reduced oropharyngeal airway dimensions, the reduction is lesser in cases with concomitant upper jaw osteotomies. Only scarce evidence exists currently to what happens to naso- and hypo-pharyngeal airways. There is no evidence for post-surgical OSA, even though some studies reported reduced respiratory parameters after single-jaw mandibular setback with or without concomitant upper jaw osteotomies.

    CONCLUSION: Although mandibular setback osteotomies reduce pharyngeal airway dimensions, evidence confirming post-surgical OSA was not found. Nevertheless, potential post-surgical OSA should be taken into serious consideration during the treatment planning of particular orthognathic cases. As moderate evidence exists that double-jaw surgeries lead to less compromised post-surgical pharyngeal airways, they should be considered as the method of choice especially in cases with severe dentoskeletal Class III deformity.

    STUDY REGISTRATION: PROSPERO (registration number: CRD42016046484).

  7. Tan SK, Leung WK, Tang ATH, Tse ECM, Zwahlen RA
    Plast Reconstr Surg Glob Open, 2017 Dec;5(12):e1608.
    PMID: 29610716 DOI: 10.1097/GOX.0000000000001608
    Background: A validated questionnaire is needed to study a more holistic outcome assessment including postsurgical aesthetic satisfaction and psychosocial changes in orthognathic patients. The aim of this study was to determine the reliability and validity of 9 orthognathically relevant translated FACE-Q scales among Hong Kong Chinese orthognathic patients.

    Methods: Two hundred fifty adult Cantonese-speaking patients of 18 years or older who underwent orthognathic treatment were recruited in the Prince Philip Dental Hospital of Hong Kong. Nine of an overall of 40 independent FACE-Q scales were selected and translated into Hong Kong Chinese. The reliability, validity, and test-retest reliability were examined using Cronbach's alpha, paired t test and Pearson's correlation coefficients.

    Results: The Hong Kong Chinese version of the 9 FACE-Q scales was obtained by forward-backward translation. One hundred eight male (mean age, 25.57 ± 4.49) and 142 female (mean age, 24.61 ± 4.54) patients were recruited for the reliability and validation process. The internal consistency (0.89-0.97) and the test-retest reliability (0.73-0.90) were found to be high. The validity of the translated questionnaires was comparable with that of the original FACE-Q.

    Conclusion: The results presented here prove that the 9 translated FACE-Q scales are reliable and valid instruments for research and clinical purposes in Hong Kong Chinese orthognathic patients.

  8. Duan ZY, Tan SK, Choon SW, Zhang MY
    Heliyon, 2023 May;9(5):e15761.
    PMID: 37205990 DOI: 10.1016/j.heliyon.2023.e15761
    This study aims to investigate the souvenir-person-place bonding for sustaining cultural heritage. Previous studies acknowledge souvenirs could represent a place; however, how people perceive souvenirs as representative of the place still needs to be studied. This study comprehends the traditional craft by identifying the dimensions of place-based craft souvenirs and exploring the connections between souvenirs, craft, and place. A qualitative approach was employed. In-depth interviews, participant and non-participant observations were conducted in Jinan, China, a long-history city with many traditional crafts. Thirty documents were imported into ATLAS.ti software for analysis. The 'place-based craft souvenir', 'evaluation of souvenir', 'place meaning', and 'satisfaction' emerged as the four main themes of 'souvenir-person-place bonding'. These 'souvenir-people-place' bonding motivate individuals' understanding of traditional craft and place, contributing to the sustainability of the traditional craft.
  9. Tan HH, Tan SK, Shunmugan R, Zakaria R, Zahari Z
    Sultan Qaboos Univ Med J, 2017 Nov;17(4):e455-e459.
    PMID: 29372089 DOI: 10.18295/squmj.2017.17.04.013
    Persistent urogenital sinus (PUGS) is a rare anomaly whereby the urinary and genital tracts fail to separate during embryonic development. We report a three-year-old female child who was referred to the Sabah Women & Children Hospital, Sabah, Malaysia, in 2016 with a pelvic mass. She had been born prematurely at 36 gestational weeks via spontaneous vaginal delivery in 2013 and initially misdiagnosed with neurogenic bladder dysfunction. The external genitalia appeared normal and an initial sonogram and repeat micturating cystourethrograms did not indicate any urogenital anomalies. She therefore underwent clean intermittent catheterisation. Three years later, the diagnosis was corrected following the investigation of a persistent cystic mass posterior to the bladder. At this time, a clinical examination of the perineum showed a single opening into the introitus. Magnetic resonance imaging of the pelvis revealed gross hydrocolpos and a genitogram confirmed a diagnosis of PUGS, for which the patient underwent surgical separation of the urinary and genital tracts.
  10. Givehchi S, Safari MJ, Tan SK, Md Shah MNB, Sani FBM, Azman RR, et al.
    Phys Med, 2018 Jan;45:198-204.
    PMID: 29373248 DOI: 10.1016/j.ejmp.2017.09.137
    PURPOSE: Accurate determination of the bifurcation angle and correlation with plaque buildup may lead to the prediction of coronary artery disease (CAD). This work evaluates two techniques to measure bifurcation angles in 3D space using coronary computed tomography angiography (CCTA).

    MATERIALS AND METHODS: Nine phantoms were fabricated with different bifurcation angles ranging from 55.3° to 134.5°. General X-ray and CCTA were employed to acquire 2D and 3D images of the bifurcation phantoms, respectively. Multiplanar reformation (MPR) and volume rendering technique (VRT) were used to measure the bifurcation angle between the left anterior descending (LAD) and left circumflex arteries (LCx). The measured angles were compared with the true values to determine the accuracy of each measurement technique. Inter-observer variability was evaluated. The two techniques were further applied on 50 clinical CCTA cases to verify its clinical value.

    RESULTS: In the phantom setting, the mean absolute differences calculated between the true and measured angles by MPR and VRT were 2.4°±2.2° and 3.8°±2.9°, respectively. Strong correlation was found between the true and measured bifurcation angles. Furthermore, no significant differences were found between the bifurcation angles measured using either technique. In clinical settings, large difference of 12.0°±10.6° was found between the two techniques.

    CONCLUSION: In the phantom setting, both techniques demonstrated a significant correlation to the true bifurcation angle. Despite the lack of agreement of the two techniques in the clinical context, our findings in phantoms suggest that MPR should be preferred to VRT for the measurement of coronary bifurcation angle by CCTA.

  11. Khor GH, Froemming GR, Zain RB, Abraham MT, Omar E, Tan SK, et al.
    Int J Med Sci, 2013;10(12):1727-39.
    PMID: 24155659 DOI: 10.7150/ijms.6884
    BACKGROUND: Hypermethylation in promoter regions of genes might lead to altered gene functions and result in malignant cellular transformation. Thus, biomarker identification for hypermethylated genes would be very useful for early diagnosis, prognosis, and therapeutic treatment of oral squamous cell carcinoma (OSCC). The objectives of this study were to screen and validate differentially hypermethylated genes in OSCC and correlate the hypermethylation-induced genes with demographic, clinocopathological characteristics and survival rate of OSCC.

    METHODS: DNA methylation profiling was utilized to screen the differentially hypermethylated genes in OSCC. Three selected differentially-hypermethylated genes of p16, DDAH2 and DUSP1 were further validated for methylation status and protein expression. The correlation between demographic, clinicopathological characteristics, and survival rate of OSCC patients with hypermethylation of p16, DDAH2 and DUSP1 genes were analysed in the study.

    RESULTS: Methylation profiling demonstrated 33 promoter hypermethylated genes in OSCC. The differentially-hypermethylated genes of p16, DDAH2 and DUSP1 revealed positivity of 78%, 80% and 88% in methylation-specific polymerase chain reaction and 24% and 22% of immunoreactivity in DDAH2 and DUSP1 genes, respectively. Promoter hypermethylation of p16 gene was found significantly associated with tumour site of buccal, gum, tongue and lip (P=0.001). In addition, DDAH2 methylation level was correlated significantly with patients' age (P=0.050). In this study, overall five-year survival rate was 38.1% for OSCC patients and was influenced by sex difference.

    CONCLUSIONS: The study has identified 33 promoter hypermethylated genes that were significantly silenced in OSCC, which might be involved in an important mechanism in oral carcinogenesis. Our approaches revealed signature candidates of differentially hypermethylated genes of DDAH2 and DUSP1 which can be further developed as potential biomarkers for OSCC as diagnostic, prognostic and therapeutic targets in the future.

  12. Mustafa NWNA, Ahmad R, Ahmad Khushaini MA, Kamar Affendi NH, Ab Ghani SM, Tan SK, et al.
    ACS Biomater Sci Eng, 2024 Jan 08;10(1):405-419.
    PMID: 38040671 DOI: 10.1021/acsbiomaterials.3c01551
    This study assessed the corrosion resistance, intracutaneous reactivity, acute systemic toxicity, and in situ tissue effect of the implantation of porous NiTi fabricated by metal injection molding in animal models. For the intracutaneous reactivity study, five intracutaneous injections were administered per site with and without the tested extract in polar and nonpolar solutions. The extract was also delivered via intravenous and intraperitoneal routes for acute systemic toxicity. TiAl6 V4 (control) and porous NiTi were implanted in rabbit femora for a period of 13 weeks to evaluate the in situ tissue response. Corrosion was evaluated through open and cyclic polarization in PBS, while biocompatibility was investigated by assessing the general conditions, skin irritation score (edema and erythema), and histopathology. No active dissolution or hysteresis loop was observed in the corrosion study. None of the animals exhibited death, moribundity, impending death, severe pain, self-mutilation, or overgrooming. No edema was observed at injection sites. Only the positive control showed an erythematous reaction at 24, 48, and 72 h observations (p < 0.001). Porous NiTi showed a low in situ biological response for inflammation, neovascularization, and fibrosis in comparison to the control implant (p = 0.247, 0.005, and 0.011, respectively). Porous NiTi also demonstrated high pitting corrosion resistance while causing no acute hypersensitivity or acute systemic toxicity. The study concludes that porous NiTi implants were unlikely to cause local sensitization, acute systemic toxicity, or chronic inflammatory reactions in an animal model. Porous NiTi also exhibited osseointegration equivalent to Ti6AI4 V of known biocompatibility.
  13. Lim WK, Wong MN, Tan SK
    Med J Malaysia, 2014 Jun;69(3):138-9.
    PMID: 25326356 MyJurnal
    A late preterm newborn baby presented with respiratory distress and increasing cyanosis within 2 hours of birth. Bedside transthroracic echocardiography showed a critically obstructed vertical vein in a supracardiac total anomalous pulmonary venous drainage (TAPVd). Emergency stenting of the vertical vein was successfully performed at 24 hours of life.
  14. Tan CS, Noni V, Melina WUHU, Abdorahman US, Bimbang JN, Malik NMA, et al.
    Sci Rep, 2022 09 19;12(1):15665.
    PMID: 36123431 DOI: 10.1038/s41598-022-19776-3
    Several vaccines have been fast-tracked through clinical trials to mitigate the progression of the SARS‑CoV‑2 pandemic. We analyzed sequential blood samples from 314 recipients of Comirnaty and CoronaVac in East Malaysia for the spike-binding IgG (IgG-S), nucleocapsid-binding IgG (IgG-N), spike-binding IgM (IgM-S) and serum vitamin D (VitD). A subset of samples was analyzed for the neutralizing antibodies (Ig-RBD). Results showed that IgG-S due to Comirnaty was significantly higher than CoronaVac. IgM-S was detected in 80.0% Comirnaty and 69.5% CoronaVac recipients, while IgG-N was detected in 58.1% CoronaVac but not in Comirnaty recipients. All IgG-S-positive vaccines possessed detectable Ig-RBD after the second dose but with a weak to moderate correlation. The serum VitD levels did not influence the antibody magnitude in both vaccines. In essence, SARS-CoV-2 vaccination is an IgG-S-dominant event, Comirnaty was more effective than CoronaVac in mounting IgG-S and Ig-RBD responses, independent of the patient's VitD level.
  15. Wang M, Fu X, Zhang D, Chen F, Liu M, Zhou S, et al.
    Sci Total Environ, 2023 Jul 01;880:163470.
    PMID: 37076008 DOI: 10.1016/j.scitotenv.2023.163470
    Global climate change and rapid urbanization, mainly driven by anthropogenic activities, lead to urban flood vulnerability and uncertainty in sustainable stormwater management. This study projected the temporal and spatial variation in urban flood susceptibility during the period 2020-2050 on the basis of shared socioeconomic pathways (SSPs). A case study in Guangdong-Hong Kong-Macao Greater Bay Area (GBA) was conducted for verifying the feasibility and applicability of this approach. GBA is predicted to encounter the increase in extreme precipitation with high intensity and frequency, along with rapid expansion of constructed areas, resulting in exacerbating of urban flood susceptibility. The areas with medium and high flood susceptibility will be expected to increase continuously from 2020 to 2050, by 9.5 %, 12.0 %, and 14.4 % under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. In terms of the assessment of spatial-temporal flooding pattern, the areas with high flood susceptibility are overlapped with that in the populated urban center in GBA, surrounding the existing risk areas, which is consistent with the tendency of construction land expansion. The approach in the present study will provide comprehensive insights into the reliable and accurate assessment of urban flooding susceptibility in response to climate change and urbanization.
  16. Dayrat B, Goulding TC, Apte D, Aslam S, Bourke A, Comendador J, et al.
    Zookeys, 2020;972:1-224.
    PMID: 33071542 DOI: 10.3897/zookeys.972.52853
    The genus Peronia Fleming, 1822 includes all the onchidiid slugs with dorsal gills. Its taxonomy is revised for the first time based on a large collection of fresh material from the entire Indo-West Pacific, from South Africa to Hawaii. Nine species are supported by mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) sequences as well as comparative anatomy. All types available were examined and the nomenclatural status of each existing name in the genus is addressed. Of 31 Peronia species-group names available, 27 are regarded as invalid (twenty-one synonyms, sixteen of which are new, five nomina dubia, and one homonym), and four as valid: Peronia peronii (Cuvier, 1804), Peronia verruculata (Cuvier, 1830), Peronia platei (Hoffmann, 1928), and Peronia madagascariensis (Labbé, 1934a). Five new species names are created: P. griffithsi Dayrat & Goulding, sp. nov., P. okinawensis Dayrat & Goulding, sp. nov., P. setoensis Dayrat & Goulding, sp. nov., P. sydneyensis Dayrat & Goulding, sp. nov., and P. willani Dayrat & Goulding, sp. nov.Peronia species are cryptic externally but can be distinguished using internal characters, with the exception of P. platei and P. setoensis. The anatomy of most species is described in detail here for the first time. All the secondary literature is commented on and historical specimens from museum collections were also examined to better establish species distributions. The genus Peronia includes two species that are widespread across the Indo-West Pacific (P. verruculata and P. peronii) as well as endemic species: P. okinawensis and P. setoensis are endemic to Japan, and P. willani is endemic to Northern Territory, Australia. Many new geographical records are provided, as well as a key to the species using morphological traits.
  17. Dayrat B, Goulding TC, Khalil M, Comendador J, Xuân QN, Tan SK, et al.
    Zookeys, 2019;877:31-80.
    PMID: 31592220 DOI: 10.3897/zookeys.877.36698
    As part of an ongoing effort to revise the taxonomy of air-breathing, marine, onchidiid slugs, a new genus, Laspionchis Dayrat & Goulding, gen. nov., is described from the mangroves of South-East Asia. It includes two new species, Laspionchis boucheti Dayrat & Goulding, sp. nov., and Laspionchis bourkei Dayrat & Goulding, sp. nov., both distributed from the Malacca Strait to the Philippines and Australia. This study is based on extensive field work in South-East Asia, comparative anatomy, and both mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) DNA sequences. The two new species are found in the same habitat (mud surface in mangrove forests) and are externally cryptic but are distinct anatomically. Both species are also strongly supported by DNA sequences. Three cryptic, least-inclusive, reciprocally-monophyletic units within Laspionchis bourkei are regarded as subspecies: L. bourkei bourkei Dayrat & Goulding, ssp. nov., L. bourkei lateriensis Dayrat & Goulding, ssp. nov., and L. bourkei matangensis Dayrat & Goulding, ssp. nov. The present contribution shows again that species delineation is greatly enhanced by considering comparative anatomy and nuclear DNA sequences in addition to mitochondrial DNA sequences, and that thorough taxonomic revisions are the best and most efficient path to accurate biodiversity knowledge.
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