MyMedR

Periodontal response to two intracanal medicaments in replanted monkey incisors

Thong YL, Messer HH, Siar CH, Saw LH

Dent Traumatol, 2001 Dec;17(6):254-9.

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.

Fulltext Conservative surgical management of ameloblastoma of the mandible--report on three cases

Foo GC, Siar CH, Ling KC, Chin CT

Med J Malaysia, 1983 Dec;38(4):334-8.

PMID: 6599995

Features of the typical ameloblastoma of the mandible are outlined. Three cases managed by conservative surgical treatment maintaining the continuity of the mandible are described. The factors taken into consideration when instituting this method of treatment are discussed. Results obtained are encouraging.

Squamous cell carcinoma of the oral mucosa in Malaysia--any change?

Ng KH, Siar CH, Ramanathan K, Murugasu P, Chelvanayagam PI

Southeast Asian J. Trop. Med. Public Health, 1985 Dec;16(4):602-6.

PMID: 3835704

The prevalence rate of 749 cases of oral squamous cell carcinomas (SCC) recorded between 1978-1984 was studied. Results showed that the Indians formed the dominant group (63.8%) followed by the Malays (19.6%) and Chinese (16.6%). The peak incidences were generally located between the sixth and eighth decades. Only in the Chinese group a male preponderance was noted. In the Indians, the buccal mucosa was the most prevalent site; in the Malays and Chinese males, the gingiva and alveolus; and the Chinese female, the tongue. In all three groups, the well-differentiated SCC was the commonest type and the poorly differentiated least common.

Pseudo bilateral tonsilloliths: a case report and review of the literature

Ram S, Siar CH, Ismail SM, Prepageran N

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2004 Jul;98(1):110-4.

PMID: 15243480

Tonsilloliths are very rare concretions found in the tonsillar crypt. They are usually single and unilateral, but occasionally may be multiple or bilateral. Small concretions in the tonsils are common, but well formed giant unilateral or bilateral tonsilloliths are extremely uncommon. Only two cases of bilateral tonsilloliths have so far been reported in the literature. A case of unilateral tonsillolith, mimicking bilateral tonsilloliths taken with the orthopantogram (OPT) in a 57-year-old Malaysian Indian female with squamous cell carcinoma of the oral cavity is described. Although the OPT is a reliable and standard panoramic X-ray unit used in dentistry, superimposition of a lesion involving one side of the jaw creates a pseudo or ghost image on the contralateral side leading to a misdiagnosis of bilateral lesions. This report highlights that tonsilloliths, though rare, should be considered in the differential diagnosis of radiopaque masses involving the mandibular ramus, and that investigations such as CT scan or MRI may be required to differentiate pseudo or ghost images from true bilateral pathologies.

Osteosarcoma presenting as an aggressive nodular mass in the region of the mandible

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.

Osteoma of the condyle as the cause of limited-mouth opening: a case report

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.

Atypical peripheral ameloblastoma of the palate

Siar CH, Ng KH, Ngui CH, Chuah CH

J Laryngol Otol, 1990 Mar;104(3):252-4.

PMID: 2341785

Clinical, radiological and histological characteristics of the peripheral ameloblastoma are briefly outlined. A case found occurring in the palate and presenting with atypical histological features is reported. The differential diagnosis of this lesion, its treatment and histogenesis are discussed.

Squamous odontogenic tumor of the mandible: a case report demonstrating immunoexpression of Notch1, 3, 4, Jagged1 and Delta1

Siar CH, Nakano K, Ng KH, Tomida M, Nagatsuka H, Kawakami T

Eur J Med Res, 2010 Apr 08;15(4):180-4.

PMID: 20554499

BACKGROUND: Squamous odontogenic tumor (SOT) is a rare benign odontogenic epithelial neoplasm. A slow-growing painless expansive swelling is the common presenting symptom. Histopathologically, SOT can be easily misdiagnosed as an acanthomatous ameloblastoma. Although Notch receptors and ligands have been shown to play a role in cell fate decisions in ameloblastomas, the role of these cell signaling molecules in SOT is unknown.

CASE REPORT: This paper describes a case of SOT affecting the anterior mandible of a 10-year-old Indian female. The patient was treated by local surgical excision and there has been no follow-up clinical record of recurrence 5 years after primary treatment. Histo?pathological examination revealed a solid, locally-infiltrative neoplasm composed of bland-looking squamatoid islands scattered in a mature fibrous connective tissue stroma and the diagnosis was SOT. Immunohistochemical evaluation showed positive reactivity of varying intensity in the neoplastic epithelial cells for Notch1, Notch3, Notch4, and their ligands Jagged1 and Delta1. Expression patterns showed considerable overlap. No immunoreactivity was detected for Notch2 and Jagged2.

CONCLUSIONS: Present findings suggest that Notch receptors and their ligands play differential roles in the cytodifferentiation of SOT.

An unsuspected ameloblastoma in the subpontic region of the mandible with consideration of pathogenesis from the radiographic course

Siar CH, Nakano K, Chelvanayagam PI, Ng KH, Nagatsuka H, Kawakami T

Eur J Med Res, 2010 Mar 30;15(3):135-8.

PMID: 20452900

The purpose of this report is to document a case of unsuspected ameloblastoma involving the right man dibular subpontic region in a 38-year-old Cambodian female patient. This lesion was purportedly preceded by multiple radiolucencies which were diagnosed as radicular cysts and treated a few times in the past years by enucleation followed by endodontic therapy of the affected teeth. Bridgework restoration of the partially edentulous area was performed. This case report demonstrates radiographic changes that occurred in the periods before and after the diagnosis of ameloblastoma. The case may represent an example of radicular cysts and ameloblastoma occurring as a collision phenomenon, or the ameloblastoma may have arisen as a result of neoplastic transformation of the lining epithelium in an inflammatory odontogenic epithelial cyst.

Fulltext Atypical neurilemmomas of the tongue--report of two cases.

Siar CH, Ng KH, Chia TY, Kulkarni MG

Singapore Med J, 1988 Feb;29(1):83-5.

PMID: 3406779

The aetiology, clinical and histological features of neurilemmomas of the oral and paraoral regions are briefly outlined. Two cases of atypical neurilemmomas of the tongue are described with an intent to document the partial encapsulation and multilobular distribution of the neurogenic tissue noted in these two lesions.

The opposing roles of NOTCH signalling in head and neck cancer: a mini review

Yap LF, Lee D, Khairuddin A, Pairan MF, Puspita B, Siar CH, et al.

Oral Dis, 2015 Oct;21(7):850-7.

PMID: 25580884 DOI: 10.1111/odi.12309

NOTCH signalling can exert oncogenic or tumour suppressive effects in both solid and haematological malignancies. Similar to T-cell acute lymphoblastic leukaemia (T-ALL), early studies suggested a pro-tumorigenic role of NOTCH in head and neck squamous cell carcinoma (HNSCC), mainly based on the increased expression levels of the genes within the pathway. Recently, data from exome sequencing analyses unexpectedly pointed to a tumour suppressor role for NOTCH in HNSCC by identifying loss-of-function mutations in the NOTCH1 gene in a significant proportion of patients. These data have questioned the accepted role of NOTCH in HNSCC and the possible rationale of targeting NOTCH in this disease. This review summarises the current information on NOTCH signalling in HNSCC and discusses how this pathway can apparently exert opposing effects within the same disease.

RANK, RANKL, and OPG in recurrent solid/multicystic ameloblastoma: their distribution patterns and biologic significance

Siar CH, Tsujigiwa H, Ishak I, Hussin NM, Nagatsuka H, Ng KH

Oral Surg Oral Med Oral Pathol Oral Radiol, 2015 Jan;119(1):83-91.

PMID: 25446507 DOI: 10.1016/j.oooo.2014.09.017

To determine the distribution patterns of bone resorption regulators, receptor activator of nuclear factor κ-B (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in recurrent ameloblastoma (RAs) and to clarify their impact on the biologic behavior of these neoplasms.

Histologic, histomorphometric, and cone-beam computerized tomography analyses of calcium sulfate and platelet-rich plasma in socket preservation: a pilot study

Cheah CW, Vaithilingam RD, Siar CH, Swaminathan D, Hornbuckle GC

Implant Dent, 2014 Oct;23(5):593-601.

PMID: 25192162 DOI: 10.1097/ID.0000000000000148

To assess dimensional changes and histologic/histomorphometric aspects of grafted sockets using either calcium sulfate-platelet-rich plasma (CS-PRP) or CS alone in socket preservation procedure.

Identifying factors associated with diagnostic concordance/discordance in oral lichen planus

Siar CH, Lim JS, Tang SP, Chia HS, Loh YM, Ng KH

J Oral Maxillofac Surg, 2013 Oct;71(10):1688-93.

PMID: 23773425 DOI: 10.1016/j.joms.2013.04.026

To identify factors associated with concordance and discordance between clinical and histopathologic diagnoses of oral lichen planus lesions.

Cementum status in natural teeth opposing implant-borne bridgework in Macaca fascicularis

Siar CH, Pua CK, Toh CG, Romanos G, Ng KH

Oral Surg Oral Med Oral Pathol Oral Radiol, 2012 Nov;114(5 Suppl):S46-53.

PMID: 23083955 DOI: 10.1016/j.tripleo.2011.07.049

The objective of this study was to investigate the cementum status in natural teeth opposing implant-supported bridgework.

Differential expression of canonical and non-canonical Wnt ligands in ameloblastoma

Siar CH, Nagatsuka H, Han PP, Buery RR, Tsujigiwa H, Nakano K, et al.

J Oral Pathol Med, 2012 Apr;41(4):332-9.

PMID: 22077561 DOI: 10.1111/j.1600-0714.2011.01104.x

Canonical and non-canonical Wnt signaling pathways modulate diverse cellular processes during embryogenesis and post-natally. Their deregulations have been implicated in cancer development and progression. Wnt signaling is essential for odontogenesis. The ameloblastoma is an odontogenic epithelial neoplasm of enamel organ origin. Altered expressions of Wnts-1, -2, -5a, and -10a are detected in this tumor. The activity of other Wnt members remains unclarified.

Dimensional profile of oral mucosa around combined tooth-implant-supported bridgework in macaque mandible

Siar CH, Toh CG, Ali TB, Seiz D, Ong ST

Clin Oral Implants Res, 2012 Apr;23(4):438-46.

PMID: 21435011 DOI: 10.1111/j.1600-0501.2010.02145.x

A stable oral mucosa is crucial for long-term survival and biofunctionality of implants. Most of this evidence is derived from clinical and animal studies based solely on implant-supported prosthesis. Much less is known about the dimensions and relationships of this soft tissue complex investing tooth-implant-supported bridgework (TISB). The aim here was to obtain experimental evidence on the dimensional characteristics of oral mucosa around TISB with two different abutment designs.

Notch4 overexpression in ameloblastoma correlates with the solid/multicystic phenotype

Siar CH, Nagatsuka H, Chuah KS, Rivera RS, Nakano K, Ng KH, et al.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2010 Aug;110(2):224-33.

PMID: 20659700 DOI: 10.1016/j.tripleo.2010.03.009

Notch signaling has been implicated in cell fate decisions during odontogenesis and tumorigenesis of some odontogenic neoplasms; however, its role in solid/multicystic (SA), unicystic (UA), and recurrent (RA) ameloblastoma remains unclear. The aim of this study was to determine Notch receptor and ligand expressions in these subtypes and to speculate on their significance.

Differential expression of Notch receptors and their ligands in desmoplastic ameloblastoma

Siar CH, Nakano K, Han PP, Nagatsuka H, Ng KH, Kawakami T

J Oral Pathol Med, 2010 Aug 1;39(7):552-8.

PMID: 20337864 DOI: 10.1111/j.1600-0714.2009.00871.x

In mammals, the Notch gene family encodes four receptors (Notch1-4), and all of them are important for cell fate decisions. Notch signaling pathway plays an essential role in tooth development. The ameloblastoma, a benign odontogenic epithelial neoplasm, histologically recapitulates the enamel organ at bell stage. Notch has been detected in the plexiform and follicular ameloblastoma. Its activity in the desmoplastic ameloblastoma is unknown.

Influence of abutment design on clinical status of peri-implant tissues

Taiyeb-Ali TB, Toh CG, Siar CH, Seiz D, Ong ST

Implant Dent, 2009 Oct;18(5):438-46.

PMID: 22129962 DOI: 10.1097/ID.0b013e3181ad8e7a

To compare the clinical soft tissue responses around implant tooth-supported 3-unit bridges using tapered abutments with those using butt-joint abutments.

Displaying publications 61 - 80 of 91 in total