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Biomedical subjects

H S Loh

Publications and source records attributed to H S Loh.

At least 19 recordsLinked to original sources
PubMed2003

Characterization of a novel rat cytomegalovirus (RCMV) infecting placenta-uterus of Rattus rattus diardii.

A new rat cytomegalovirus (RCMV) isolated from the placenta/uterus of a house rat (Rattus rattus diardii) was found to productively infect rat embryo fibroblast (REF) cells. The virus produced typical herpesvirus-like cytopathic effects characterized by a lytic infection. The well-known herpesvirus morphology was confirmed by electron microscopy. Its slow growth in cell culture indicated that the virus is belonging to subfamily Betaherpesvirinae. Electron microscopy techniques and immunohistochemistry confirmed the presence of herpesviral inclusion bodies and virus related particles in the cytoplasm and nucleus of infected cells. Hyperimmune serum against the Maastricht strain of RCMV revealed the virus identity in neutralization test, immunoperoxidase and immunofluorescence techniques. Despite typical characteristics of CMV, the viral genome is significantly different from that of Maastricht, English, UPM/Sg and UPM/Kn strains. The dissimilarities, which have not been reported before, had been confirmed by mean of restriction endonuclease analysis. The new RCMV strain, a virus that infects placenta and uterus of rats, has been named as ALL-03.

Animals↗
PubMed2000

Case reports: the use of intermaxillary screws to achieve intermaxillary fixation in the treatment of mandibular fractures.

INTRODUCTION: Treatment of mandibular fractures commonly involves the use of arch bars in temporary maxillo-mandibular fixation (also called intermaxillary fixation) to aid bone plating, for the postoperative application of light elastic traction to correct minor occlusal discrepancies and intermaxillary fixation for post reduction immobilisation. The purpose of this paper is to describe a quick and simple alternative for intermaxillary fixation. CLINICAL PICTURE: Three cases of mandibular fractures are presented to demonstrate the use of intermaxillary screws instead of conventional arch-bar wiring. TREATMENT: Two cases were treated with closed reduction methods while the other case was treated with open reduction. OUTCOME: Subsequent fracture healing was not compromised using this technique. CONCLUSIONS: With careful case selection, successful treatment outcome may be achieved using this time-saving and technically simple procedure. Some of the advantages and disadvantages of the intermaxillary screws are discussed.

Adult↗
PubMed1998

Trigeminal neuralgia. A retrospective survey of a sample of patients in Singapore and Malaysia.

This survey was undertaken to study the clinical features of trigeminal neuralgia in an Asian population. Demographic data of 44 patients treated at the Dental Faculty of the National University of Singapore and at the University of Malaya were reviewed. The results of the survey were analysed and comparisons made with those of Caucasian patients as reported in other studies where there was a general similarity in the clinical findings. Trigeminal neuralgia presented predominantly in females. Right-sided involvement occurred at a greater frequency, and the peak age at onset was between the sixth and seventh decades of life. The only significant variant in the present sample was the greater involvement of the mandibular branch of the trigeminal nerve rather than the maxillary division. In addition, there was a much greater representation from Chinese patients over Malays as compared with their ratios in the general population.

Adult↗
PubMed1998

Root morphology of the maxillary first premolar in Singaporeans.

Extracted teeth were collected from clinical procedures performed in the Faculty of Dentistry, National University of Singapore. A selected sample of 957 maxillary first premolars were subjected to visual examination and digital radiography. There was a higher incidence of two-root form (50.6 per cent) than previously reported for the Singaporean dentition. In the two-root category, 307 teeth exhibited the fused-root form (two fused roots with two root canals) and 177 were distinctively of the two-root form (two separate roots with two root canals and two foramina). The fused-root form was emphasized as an entity in this study. The one-root form accounted for 49.4 per cent. No three-root form was detected.

Bicuspid↗
PubMed1997

Bilateral coronoid hyperplasia--a report with a view on its management.

Bilateral coronoid hyperplasia requires surgery (coronoidectomy) to improve mouth opening. An intra-oral approach is preferred with direct fibre-optic anaesthetic intubation. Myotomy of the masseter muscle is recommended in cases where fibrotic and calcifying effects have occurred. Pre-operative physiotherapy counselling and post-operative jaw exercises are important to the final success of the management.

Adolescent↗
PubMed1993

Coronal morphology of the mandibular second premolar in the Singaporean Chinese.

Five hundred and sixty-four patients of Singaporean Chinese origin with bilateral second premolars present were screened. Morphological features of the crown, number and position of cusps and the sex of the patient were recorded. The mesio-distal dimensions of the crowns were measured. Three hundred and seventy-four (66.3 per cent) exhibited bilateral 2-cusp forms; 143 (25.4 per cent) were 3-cusp forms; and 47 (8.3 per cent) were mixed. There was no sex predilection in the three groups. In the 2-cusp forms, the predominant occlusal pattern was H-shaped (75.9 per cent). The 3-cusp type with a Y-shaped pattern and a squarish outline is a significant morphological and racial characteristic in the local population. The presence of 2-cusp and 3-cusp forms in an individual is an unusual developmental phenomenon.

Asian People↗
PubMed1992

The treatment of epulis fissuratum of the oral cavity by CO 2 laser surgery.

A clinical study was conducted on a group of 20 patients who presented with epulis fissuratum caused by denture wearing. CO 2 laser surgery was used to treat these patients and the cases were followed up over a two-year period. The advantage of CO 2 laser surgery on oral tissues was evident by the good response to healing four weeks postoperatively and beyond. No sutures or packing of any kind were used and the wound was allowed to granulate. Re-epithelialization occurred in all patients within 14 days and was complete after about 4 weeks. The lack of wound contraction, scarring, and good re-epithelialization combined with precise tissue destruction make CO 2 laser surgery ideal for this procedure when compared with conventional surgical techniques. The advantage of using CO 2 laser surgery has been demonstrated clinically in the patients treated in this study.

Adult↗
PubMed1992

A clinical investigation of the management of oral lichen planus with CO 2 laser surgery.

Ten patients with an established histologic diagnosis of lichen planus on various sites of the oral cavity were treated with CO 2 laser therapy under local anesthesia. Power output of 5 W at continuous mode was applied to vaporize the lesions. Eradication was achieved by aiming the laser in a moving criss-cross pattern with defocused spatial overlap. Depth of removal was subepithelial. No suturing of the wound was done. Follow-up occurred at intervals from 6 months to 4 years. The average length was about 3 years. Postlaser healing was uneventful, with little pain, swelling, or bleeding. There was immediate relief in all patients of associated burning sensations and a tolerance to hot and spicy foods. This symptomatic improvement lasted throughout the follow-up. Reepithelialization produced little visible scarring, and the mucosa color and texture were close to normal. Alterations in the immunologic status of the patients were implicated. Histologic rebiopsy in two cases suggested significant improvement, normalization of the epithelium, and a reduction of the subepithelial infiltrate. The CO 2 laser is effective in the immediate relief of symptoms and contributes to the clinical improvement of oral lichen planus. Immunologic studies and long-term follow-up are suggested.

Adult↗
PubMed1991

'A bridge too far ...'. Case report.

An elderly man was assaulted and sustained facial injuries with fractures of the mandible and left zygoma. An unusual complication of aspiration of an intact four-unit metal bridge is reported. Immediate retrieval was done under general anaesthesia by rigid bronchoscopy. The technique is described. The importance of careful clinical and radiographic examination is stressed.

Bronchoscopy↗
PubMed1991

A ten-year follow-up case report following surgical correction of anterior open bite.

A case is reported whereby an anterior open-bite was treated with the Köle osteotomy in an adult Chinese girl. This study documents cephalometrically the post-treatment changes occurring in the dento-alveolar complex over a ten year follow-up period and describes the possible mechanisms contributing to the remarkable stability of the open-bite correction.

Adolescent↗
PubMed1991

Primitive neuroectodermal tumour in the oral cavity. Case report.

Primitive neuroectodermal tumour is regarded as a rarely seen lesion as it occurs mainly within the central nervous system. However, this neoplasm does occasionally occur elsewhere in the body. One such case which occurred in the posterior part of the palate in a child is reported. Following a combined therapeutic approach comprising surgery, radiotherapy and chemotherapy, the patient has been well for nine years since treatment.

Child↗
PubMed1991

Mongoloid features of the permanent mandibular second molar in Singaporean Chinese.

The permanent mandibular second molar is usually described as four-cusped, two placed buccally and two lingually. It has been reported that five-cusp forms were more commonly present in dentitions of mongoloid origin. The prevalence and features of this tooth form were examined in a Singaporean sample of 380 subjects with bilateral presence of the mandibular second molars. One-hundred and sixty four cases (43.1 per cent) were found to have bilateral occurrence of five-cusp forms and thirty-four cases (8.9 per cent) with unilateral occurrence. Six-cusp forms were detected in three cases. There was almost equal prevalence in both sexes and both sides were equally involved in unilateral cases. The extra cusp was smallest, placed disto-buccally and sometimes midway at the distal border. The occlusal outline of five-cusp second molars was rectangular with a somewhat similar groove pattern to the first molar. There was an increase in the mesio-distal width of the crown. The high incidence was comparable with other studies of mongoloid dentitions and it could be considered as an important morphological and racial characteristic of the Singaporean Chinese.

Asian People↗
PubMed1990

Incidence and features of three-rooted permanent mandibular molars.

Seven hundred and eighty-six patients of Singaporean Chinese origin requiring extractions of permanent mandibular molars were screened. Personal details, identification of the tooth and the presence or absence of an extra root were recorded. Thirty-two cases (4.1 per cent) exhibited an extra disto-lingual root. None was found in the second molar. The first molar was affected (7.9 per cent) slightly more than twice as often as the third molar (3.7 per cent). The extra root was present almost equally in both sexes with a higher presentation on the left side. Six cases had a fracture of the extra root. A comparison was made with a study done by Tratman' on the same population and with other studies involving those of Chinese and Mongoloid origin in other countries.

China↗
PubMed1990

Histiocytosis X (Langerhans-cell histiocytosis) of the palate. Case report.

A case of histiocytosis X (Langerhans-cell histiocytosis) occurring in the maxilla of a two-year-old boy is presented. Common dental and oral conditions were considered and eliminated. Diagnosis was made through a biopsy which showed aggregates of histiocytes. Management consisted of multi-modal treatment. Full skeletal radiographic survey and review were essential to detect other possible sites of involvement. None was found in this case over a four-year review.

Child, Preschool↗
PubMed1990

Laser therapy for a haemophiliac. Case report.

With adequate precaution, dental procedures which are likely to cause haemorrhage in haemophiliac patients may now be performed with a greatly reduced risk. A case report of a 'moderate' haemophiliac who presented with acute pericoronitis is described. The operculum associated with an erupting molar tooth was excised using a laser beam. Pre- or post-operative infusion of Factor VIII was not required. The applications and possible implications of the use of this treatment modality are discussed.

Child↗
PubMed1990

Evaluation of soft tissue profile following intraoral ramus osteotomy in Chinese adults with mandibular prognathism.

Twenty-five Chinese adults with mandibular prognathism were treated with either the intraoral vertical subcondylar osteotomy or the bilateral sagittal split ramus osteotomy. The patients were kept in maxillomandibular fixation for 6 to 8 weeks while osteosynthesis was achieved with the use of intraosseous wiring. Serial lateral cephalograms were taken presurgery and between 12 and 26 months postsurgery, and specific soft and hard tissue points were digitized on a computer. The mean mandibular setback postsurgically was 8.4 +/- 3.2 mm, with a 5.2-degree reduction in point A-nasion-point B angle. Posterior movement of pogonion, point B and the mandibular incisal edge was accompanied by posterior movement of 95% at soft tissue pogonion (r = .96), 89% at soft tissue point B (r = .83), and 67% at labrale inferius (r = .81), respectively. The correlation between changes in the labrale superius and mandibular setback appeared to be dependent on both the amount of mandibular setback and the degree of mandibular rotation during the setback surgery. The presently reported ratios of the soft tissue response to hard tissue movement vary from those reported in white patients by other researchers, which confirms the need for different ratios for different racial types.

Adult↗
PubMed1989

The effectiveness of CO2 laser in dental surgery--a local experience.

The CO2 laser was introduced in Singapore in 1985 for dental surgery. It delivered a novel and brilliant adjunct for management of orofacial lesions and conditions. Tissue destruction is precise, immediate and quite bloodless. Oedema is not remarkable and healing produces minimal scarring. For small mucosal lesions, a power of 5 to 10 watts is sufficient. It is particularly useful for broad-based lesions and white lesions in the oral cavity. For major oral surgery, a power of 20 watts would be adequate for surgical excision. It reduces the invasiveness and trauma of surgery and lowers post-operative complications. The effects on dental hard tissues provide an exciting area for development and research and its uses here are gaining acceptance.

Carbon Dioxide↗