Displaying all 10 publications

  1. Rajandram RK, Jenewein J, McGrath CP, Zwahlen RA
    Oral Oncol, 2010 Nov;46(11):791-4.
    PMID: 20850373 DOI: 10.1016/j.oraloncology.2010.08.010
    Recently the importance of posttraumatic growth (PTG), a phenomenon of positive psychological growth beyond baseline values, has been discovered in the field of oncology. An evidence based review of the literature regarding PTG was performed, both to support its understanding and to consider its application within the research field of oral cavity (OC) cancer. A Pubmed, Medline, PsycINFO search from the earliest date until April 2010 was carried out. Full articles meeting the inclusion and exclusion criteria were reviewed. The search yielded 852 papers, 91 'potentially relevant papers' and 29 'effective papers', the latter of which formed the basis of this review. PTG was assessed in twenty-eight studies with the Posttraumatic Growth Inventory and in only one study with the Perceived Benefits Scale (PBS). PTG in cancer patients has been reported in five main domains (i) appreciation of life, (ii) relating to others, (iii) increased personal sense, (iv) sense of new possibilities and (v) positive spiritual change. Socio-demographic factors, stressor characteristics and coping strategies influence and predict the development PTG. In the past decade an increasing interest in the concept of PTG in the field of oncology has emerged. This evidence based review presents PTG to the research community in the field of OC cancer, appraises its modification capacity of the treatment outcome in other cancer research fields and hypothesizes its eventual benefit in the field of OC cancer research.
  2. 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 

  3. 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.

  4. 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 

  5. 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.

  6. 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.

  7. 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).

  8. Mustafa A, Lung CY, Mustafa NS, Mustafa BA, Kashmoola MA, Zwahlen RA, et al.
    Clin Oral Implants Res, 2016 Mar;27(3):303-9.
    PMID: 25393376 DOI: 10.1111/clr.12525
    OBJECTIVES: To investigate the effect of eicosapentaenoic acid (EPA)-coated Ti implants on osteoconduction in white New Zealand rabbit mandibles.

    MATERIAL AND METHODS: Sandblasted and cleansed planar titanium specimens with a size of 5 × 5 × 1 mm were coated on one side with 0.25 vol% eicosapentaenoic acid (EPA). The other side of the specimens was kept highly polished (the control side). These specimens were inserted in rabbit mandibles. Twelve rabbits were randomly assigned into three study groups (n = 4). The rabbits were sacrificed at 4, 8, and 12 weeks. The harvested specimens with the implants were assessed for new bone formation on both sides of the implant using CBCT, conventional radiographs, and the biaxial pullout test. The results were statistically analyzed by a nonparametric Kruskal-Wallis test and Friedman's test as multiple comparisons and by Brunner-Langer nonparametric mixed model approach (R Software).

    RESULTS: A significant osteoconductive bone formation was found on the EPA-coated Ti implant surface (P < 0.05) at 8 weeks when compared to the polished surface (control). Biaxial pullout test results showed a significant difference (P < 0.05) after 8 and 12 weeks with a maximum force of 243.8 N, compared to 143.25 N after 4 week.

    CONCLUSION: EPA implant coating promoted osteoconduction on the Ti implant surfaces, enhancing the anchorage of the implant to the surrounding bone in white New Zealand rabbits.

  9. 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.

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