Displaying publications 41 - 60 of 91 in total

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  1. Ong ST, Shim CK, Ng KH, Siar CH
    J Oral Sci, 2004 Mar;46(1):55-9.
    PMID: 15141725
    Osteosarcomas are highly malignant neoplasms of bone that are challenging to diagnose. These neoplasms often show atypical behavior. In the initial phase they may present as nondescript bony swellings with an indolent growth rate, only to become overtly aggressive and malignant towards the later phase of the disease. Similarly, the histological growth pattern of this neoplasm can be quite diverse, presenting with areas that mimic benign myofibroblastic tumors, giant cell granulomatous conditions and partial encapsulation. The final diagnosis of an osteosarcoma is often reached after thorough sampling and examination of multiple biopsy specimens. All these clinical features and histological diagnostic difficulties were encountered in a case of osteosarcoma affecting the right mandible of a 62-year-old Chinese woman described here. The diagnostic lessons accrued from this case are discussed.
  2. Siar CH, Jalil AA, Ram S, Ng KH
    J Oral Sci, 2004 Mar;46(1):51-3.
    PMID: 15141724
    Osteoma is a benign tumour consisting of mature bone tissue. It is an uncommon lesion that occurs mainly in the bones of the craniofacial complex. Only a few cases involving the condylar process have been reported. An osteoma of the left condyle causing limited mouth-opening in a 32-year-old Malaysian Chinese female is reported here to alert the practitioner to consider this lesion as a diagnostic possibility in instances of trismus or limited-mouth opening.
  3. Siar CH, Ng KH, Rasool S, Ram S, Abdul Jalil A, Ng KP
    J Oral Sci, 2003 Sep;45(3):161-4.
    PMID: 14650581
    Though oral candidosis is an opportunistic fungal infection that commonly affects immunocompromised patients, little is known of its occurrence as a complication of Non-Hodgkin's lymphoma. This paper reports a case of oral candidosis in a 20-year-old Indonesian woman with this lymphoproliferative disease. She presented with acute pseudomembranous candidosis on the dorsum and lateral borders of the tongue, bilateral angular cheilitis and cheilocandidosis. The latter is a rare clinical variant of oral candidosis, and the lesions affecting the vermilion borders presented as an admixture of superficial erosions, ulcers and white plaques. Clinical findings were confirmed with oral smears and swabs that demonstrated the presence of hyphae, pseudohyphae and blastospores, and colonies identified as Candida albicans. A culture from a saline rinse was also positive for multiple candidal colonies. Lip and oral lesions were managed with Nystatin. The lesions regressed with subsequent crusting on the lips, and overall reduction in oral thrush. As Non-Hodgkin's lymphoma is a neoplastic disease that produces a chronic immunosuppressive state, management of its oral complications, including those due to oral candidosis, is considered a long-term indication.
  4. Siar CH, Toh CG, Romanos G, Swaminathan D, Ong AH, Yaacob H, et al.
    J. Periodontol., 2003 May;74(5):571-8.
    PMID: 12816287
    Today, one critical goal in implant placement is the achievement of optimal soft tissue integration. Reports thus far have demonstrated successful soft tissue preservation in delayed loaded implants placed in anterior jaws. The aim of this study was to histomorphometrically examine the soft tissues around immediately loaded implants placed in the macaque posterior mandible.
  5. Ng KH, Siar CH
    PMID: 12738952
    Although rare, hard tissue deposits, namely dystrophic calcifications and cartilage, have been reported to occur in the connective tissue wall of the odontogenic keratocyst. However, dentinoid formation has not been previously documented. A case involving the left mandibular premolar-molar region in a 37-year-old Malay male is described here along with a brief review on the reported prevalence of hard tissue deposits in the odontogenic keratocyst. Differential diagnosis of this case from other dentinoid-forming odontogenic cysts and tumors-notably calcifying odontogenic cyst, odontoma, ameloblastic fibro-odontoma, central odontogenic fibroma and adenomatoid odontogenic tumor that may present with dentin/dentinoid formation-is discussed.
  6. Thong YL, Messer HH, Siar CH, Saw LH
    Dent Traumatol, 2001 Dec;17(6):254-9.
    PMID: 11766092
    Intracanal medicaments are recommended for use in replanted teeth to inhibit inflammatory root resorption. This study compared the effect of calcium hydroxide (Pulpdent) and a corticosteroid-antibiotic paste (Ledermix) on periodontal healing and root resorption following replantation. Incisors of eight Macaca fascicularis monkeys were extracted, stored dry for 15 min and replanted. After 11 days, root canals in two adjacent maxillary incisors were treated with one medicament and contralateral incisors with the other medicament, or left as untreated controls. Animals were sacrificed 8 weeks later and the teeth prepared for histomorphometric evaluation of periodontal ligament inflammation and root resorption. Periodontal ligament inflammation and inflammatory root resorption were markedly inhibited by both calcium hydroxide and corticosteroid-antibiotic relative to untreated controls. Replacement resorption was lowest in the corticosteroid-antibiotic group, and significantly (P<0.05) more normal periodontal ligament was present in this group (79.6%) than in calcium hydroxide and control groups (64.6% and 62.7%, respectively). Treatment with the corticosteroid-antibiotic inhibited inflammatory resorption and was slightly more effective than calcium hydroxide in producing a periodontal healing response.
  7. Siar CH, Tan BH
    J Oral Sci, 2000 Dec;42(4):205-10.
    PMID: 11269378
    The turnaround time (TAT) for oral biopsies received for histological examination by the Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya, for the years 1978, 1988 and 1998 was evaluated. For the three years studied, TATs for 61, 233 and 463 specimens were retrospectively analysed. Testing intervals, that is, from the dates the surgeons procured the specimens, the laboratories accessioned them and until the pathologists signed off the diagnoses, were used to calculate TAT. The performance level of the respective pathologists, the growth of tissue diagnostic services and the possible variables that influence TAT were also evaluated. As prompt diagnosis means prompt treatment, which in turn has a bearing on prognosis, the TAT pertinent to oral malignant tumors was emphasized. The mean TAT, its mode and median fell significantly in 1998 compared with the previous 2 years; it was lower for soft tissue than for hard tissue specimens, and lower for malignant, than for non-malignant specimens. The progression of tissue diagnostic services is up to a satisfactory level, as 88.89 % of biopsies could render diagnoses within a fair period of time in 1998.
  8. Siar CH, Ng KH
    Br J Oral Maxillofac Surg, 2000 Feb;38(1):19-22.
    PMID: 10783442
    Analysis of case records of 46 patients with peripheral odontogenic fibroma (1967-95) diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, disclosed a relatively young age of onset (mean, 32.2 years; range 5 months-64 years; peak incidence second decade of life), a slight female preponderance (M:F ratio 1:1.3), no racial predilection, a slight bias towards location in the mandible (52%) and a wide histomorphological range. All cases were treated by simple excision. Follow-up records were generally not available, so we do not know what the recurrence rate is.
  9. Ong AH, Siar CH
    Aust Dent J, 1998 Aug;43(4):229-33.
    PMID: 9775467
    The cemento-ossifying fibroma is classified as an osteogenic neoplasm of the jaws. It commonly presents as a progressively growing lesion that can attain an enormous size with resultant deformity if left untreated. A case of a large cemento-ossifying fibroma involving the left mandible is described in a 15 year old male patient. The clinical, radiographic and histological features as well as surgical findings are presented. The treatment of choice of this lesion is also emphasized. Two years after surgery, there was no evidence of recurrence and the transosseous wire used to immobilize the fracture was found to be completely buried in the jaw bone.
  10. Ong ST, Siar CH
    Aust Dent J, 1997 Dec;42(6):404-8.
    PMID: 9470284
    Florid cemento-osseous dysplasia refers to a group of fibro-osseous lesions which are exuberant, multiquadrant and arise from the tooth-bearing area of the jaws. It is classically described as a condition occurring almost exclusively in middle-aged black women. A case of florid cemento-osseous dysplasia occurring in a young Chinese male is reported which was rare in regard to race and sex. This 20 year old Chinese man presented with huge symmetrical bony lesions in all four quadrants of the jaws. Clinical presentation, radiological findings and histological features of the excised specimens are described. Treatment of the lesions was unusual. Curettage was first done with minimal benefit and it was followed by mandibular recontouring to improve facial appearance. The outcome of these procedures will be discussed.
  11. Ng KH, Siar CH
    J Nihon Univ Sch Dent, 1997 Dec;39(4):171-5.
    PMID: 9476429
    This report reviews the clinicopathologic characteristics of 104 cases of odontomas diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year period (1967-1995). The results showed no real predilection in terms of sex (M:F ratio, 1:1), race (45.2% Malays, 40.4% Chinese, 10.6% Indians and 3.8% other races) or site (maxilla:mandible ratio, 1: 1.04) distribution. The mean age at presentation was 24.8 years and the age range was 3-74 years. There were 102 intraosseous and 2 extraosseous odontomas. Swelling was the most common presenting complaint. The majority of cases (81.9%) were clinically diagnosed as odontomas. The treatment of choice was surgical enucleation. Compound (43.3%) and complex (35.5%) odontomas were the two most common histological types encountered. The present findings correlate favorably with reported studies from other geographic areas.
  12. Ng KH, Siar CH, Ganesapillai T
    PMID: 9247945
    We report two cases of body piercing as a religious practice that subsequently led to the development of granulomatous nodules at previously punctured sites of the skin and oral mucosa. These lesions were diagnosed as sarcoid-like foreign body reaction after other possible causes including sarcoidosis, tuberculosis, tuberculoid leprosy, fungal infections, viral infections, and Crohn's disease were excluded.
  13. Ng KH, Siar CH
    J Laryngol Otol, 1996 Aug;110(8):757-62.
    PMID: 8869610
    We reviewed the clinicopathological characteristics of 13 cases of calcifying epithelial odontogenic tumour (CEOT) (Pindborg tumour) diagnosed in the Division on Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year period. There were eight female and five male patients. These consisted of eight (61.5 per cent) Malays, three (23.1 per cent) Chinese, one (7.7 per cent) Indian and one (7.7 per cent) Melanau. Their ages at presentation ranged from 19-61 years (mean age, 31.8 years). There were 12 central and one peripheral CEOT. Of these, 76.9 per cent of cases were located in the maxilla, the remaining in the mandible. The commonest clinical diagnosis was a dentigerous cyst (66.7 per cent). Enucleation was the main mode of treatment. Histologically, sheets and strands of polyhedral epithelial cells containing eosinophilic, homogeneous globules with Liesegang rings were observed. One case also showed extensive calcification and clear cell differentiation. Immunohistochemistry revealed a variable keratin staining of the CEOT epithelium, confirming its heterogeneity.
  14. Siar CH, Ong ST, Ng KH
    Singapore Dent J, 1996 Jul;21(1):19-22.
    PMID: 10597178
    Adenomatoid odontogenic tumours (AOT) are benign, hamartomatous odontogenic lesions that not uncommonly mimic a dentigerous cyst radiographically. Such a case as found involving an unerupted left maxillary canine in a 19-year-old Chinese female is described. The differential diagnosis of some common odontogenic cysts and neoplasms occurring in Malaysians, that may present in a dentigerous relationship to an unerupted tooth is discussed. A brief review of the radiographic literature on AOT is also included.
  15. Ng KH, Siar CH
    PMID: 8653464
    We reviewed biopsy records for 37 cases of oral histoplasmosis for patient characteristics, clinical features, and histopathologic findings. These represented cases diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur between July 1967 and October 1994. All were male patients who ranged in age from 11 to 79 years (mean age, 56.7 years). There were 40.6% Malays, 37.8% Chinese, 18.9% Indians, and 2.7% other races. Five patients with mouth lesions as the initial presenting lesions were proven to be cases of disseminated histoplasmosis. In the remaining cases apart from the biopsy-proven oral histoplasmosis lesions, the extent of the disease elsewhere was unknown. The majority of these lesions involved the gingiva, tongue, and palate in decreasing order of frequency. The most frequent presenting symptom was oral mucosal ulceration. Squamous cell carcinoma and tuberculosis were the two most common clinical differential diagnoses. Our present findings compare favorably with published reports from other regions.
  16. Ng KH, Siar CH
    J Nihon Univ Sch Dent, 1995 Sep;37(3):156-62.
    PMID: 7490609
    Calcifying odontogenic cysts (COCs) represent a group of lesions that may be broadly classified into two main entities: cysts and neoplasms. In the present study 30 non-neoplastic cystic COCs were examined by a quantitative histological method in an attempt to calibrate the relative distribution of the type of epithelial lining, intensity of ghost cell formation and the amount of dentinoid present. The results showed that there are two main types of cystic COC: an odontoma-producing type and a non-odontoma-producing variant. Morphologically, tooth-like structures were a valid distinguishing feature, while morphometrically the odontoma-producing variant showed a greater amount of luminal and mural dentinoid as well as luminal ghost cells. Demographic analysis also revealed that the odontoma-producing COC occurred in younger patients and showed an even sex distribution, whereas the non-odontoma-producing type was seen in older patients and showed a predilection for females. Both subtypes were more prevalent in the Chinese population and occurred preferentially in the maxilla.
  17. Siar CH, Ng KH
    J Nihon Univ Sch Dent, 1995 Sep;37(3):163-9.
    PMID: 7490610
    The lining epithelium of 15 cases of odontogenic keratocyst (OKC) was evaluated immunohistochemically. The peroxidase-antiperoxidase technique was applied to study the distribution of polyclonal keratin and S-100 protein while the indirect method was used to examine monoclonal vimentin and desmin reactivity. Consistent positive keratin staining was revealed in the lining epithelium of all 15 OKCs with additional intense staining in the stratum corneum. None of the cases showed vimentin or desmin reactivity within the lining epithelium elements. One of the 15 cysts studied showed positive S-100 protein staining in the nuclei of the lining epithelial cells. The pertinent literature on the immunophenotyping of the lining epithelium of OKC is reviewed.
  18. Siar CH, NG KH
    PMID: 9227094
    The clinical and histological features of the peripheral odontogenic fibroma are briefly outlined. A case arising from the attached lingual gingiva between the mandibular right permanent first molar and the second molar in a 67 year old Indian female is reported here. The unusual occurrence of marked clear cell differentiation within the odontogenic epithelial component, and histogenetic link to the clear cell rests of the dental lamina and surface epithelium are discussed.
  19. Siar CH, Ng KH
    J Laryngol Otol, 1994 Mar;108(3):269-71.
    PMID: 8169519
    A case is described of ameloblastoma of the mandible presenting with multiple recurrences and subsequent extension to the maxilla with resultant transformation into an aggressive (malignant?) epithelial odontogenic ghost cell tumour. The latter is a rare, biologically virulent entity that affects mainly males, exhibits a preference for the maxilla and is histologically characterized by atypical malignant odontogenic epithelium associated with areas of ghost cell formation and varying amounts of dentinoid.
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