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Biomedical subjects

K F Lim

Publications and source records attributed to K F Lim.

8 recordsLinked to original sources
PubMed1997

Phosphor-stimulated computed cephalometry: reliability of landmark identification.

The aim of this randomized, controlled, prospective study was to determine the reliability of computed lateral cephalometry (Fuji Medical Systems, Tokyo, Japan) in terms of landmark identification compared to conventional lateral cephalometry (CAWO, Schrobenhausen, Germany). To assess the reliability of landmark identification on lateral cephalographs, 20 computed images, taken at 30 per cent reduced radiation (70 kV, 15 mA, 0.35 s) were compared to 20 conventional images (70 kV, 15 mA, 0.5 s). The 40 lateral cephalographs were taken from 20 orthodontic patients at immediate post-treatment and 1 year after retention. The order and type of imaging was randomized. Five orthodontists identified eight skeletal, four dental and five soft tissue landmarks on each of the 40 films. The error of identification was analysed in the XY Cartesian co-ordinate following digitization. Skeletal landmarks exhibited characteristic dispersion with respect to the Cartesian co-ordinates. Root apices were more variable than crown tips. Soft tissue landmarks were more consistent in the X co-ordinate. Two-way ANOVA shows that there is no significant difference between the two imaging systems in both co-ordinates (P > 0.05). Moreover, the differences are generally small (< 0.5 mm), and are unlikely to be of clinical significance. Most of the variables attained statistical power of at least 0.8 in the X-co-ordinate while only the dental landmarks achieved statistical power of at least 0.78 in the Y-co-ordinate. Based on the results of the study: (1) computed lateral cephalographs can be taken at 30 per cent radiation reduction, compared to conventional lateral cephalograph; (2) each anatomical landmark exhibits its characteristic dispersion of error in both the Cartesian co-ordinates; (3) there is no trend between the two imaging systems, with equivocal result, and none of the landmarks attained statistical significance when both raters and imaging systems are considered as factorial variables; (4) the random error of raters in landmark identification after replicate tracing was highlighted and needs to be taken into consideration in all studies involving landmark identification.

Adolescent↗
PubMed1996

Intra-oral computed radiography--an in vitro evaluation.

OBJECTIVES: The aims of this study were to compare the intra-oral radiographic images produced by computed radiography (Digora, Soredex, Helsinki, Finland) with conventional E-speed periapical films, in terms of image quality, radiation dosage and diagnostic value. METHODS: The physical measurement of image quality was conducted with a test grating. Radiation dosage was measured with an X-ray test device. Radiographic imagings were standardized using the left first permanent molar tooth of a dry human skull. The exposure timings ranged from 0.02 s to 2.32 s. Five dental surgeons rated the quality of the images produced by both systems. All raters were blind to the order of test. RESULTS: The physical measurements of the new imaging plates revealed comparable results in terms of contrast differentiation. The resolution power, however, was slightly inferior: 5 lines/mm compared to 6 lines/mm for the E-speed films. Digital images were consistently scored as diagnostically acceptable throughout the exposure timings, while those for E-speed films range from 0.38 s to 1.8 s (P < 0.01). CONCLUSIONS: The new imaging plate gave favourable results in terms of contrast differentiation. The resolution power, however, was slightly inferior to that with the E-speed film. Digital images of diagnostic quality were obtained even at 53% reduction of radiation compared to E-speed films.

Humans↗
PubMed1996

Latex elastic-induced periodontal damage: a case report on the subsequent orthodontic management.

Proper management of a malocclusion relies on a basic understanding of the development of the dentition and the craniofacial complex. Diagnosis should only be formulated after all the relevant diagnostic records, including clinical examination and history, are reviewed. Armed with this information, the dentist forms the treatment plan. The mere occurrence of a malocclusion does not constitute a need for treatment. Injudicious intervention can be counterproductive or destructive. Through a case report, the deleterious effects of improper case management and questionable treatment mechanics are highlighted. The subsequent orthodontic management emphasizes the principles and techniques for the successful treatment of the patient in question.

Adolescent↗
PubMed1994

Bending stiffness of two aesthetic orthodontic archwires: an in vitro comparative study.

The aims of the study were to quantify the transverse stiffness of two aesthetic orthodontic archwires (0018 inch Teflon-coated stainless steel and 0017 inch Optiflex) in a simulated clinical setting and to assess the influence of deflection direction on the bending stiffness. The aesthetic archwires were randomly divided into three equal groups: group 1, lingual deflection; group 2, labial deflection; and group 3, occlusal deflection. Each group consisted of six archwires of the same type. The control group consisting of eighteen 0014 inch stainless steel archwires were also subjected to the same grouping. A total of 54 archwires were tested in the study. The deflection of the archwires was measured with a travelling microscope and the load measured with a calibrated strain gauge ring transducer. The mean stiffnesses of the archwires in the lingual, labial and occlusal deflection groups were found to be 29, 08 and 25 mN/mm respectively for 0017 inch Optiflex (r = 09, P less than 0001), 132, 105 and 245 mN/mm respectively for 0018 inch Teflon-coated stainless steel (r = 09, P less than 0001) and 266, 164 and 323 mN/mm respectively for the control (r = 09, P less than 0001). Springback was found to be poor for Optiflex and the archwire remained bent upon deactivation. ANOVA showed that the influence of arch curvature on the bending stiffness was significantly different for Optiflex (P less than 005), Teflon-coated stainless steel (P less than 0005) and the control group (P <0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Elasticity↗
PubMedDate not supplied

Ofloxacin, a new quinolone for the treatment of gonorrhea.

Forty-three patients with uncomplicated gonorrhea were treated with 400 mg of ofloxacin. All had cultures negative for Neisseria gonorrhoeae at follow-up within two weeks of treatment. Minimal side effects were reported. Ofloxacin appears to be satisfactory as a single-dose oral drug for the treatment of gonococcal urethritis, including those cases caused by penicillinase-producing strains of N. gonorrhoeae.

Administration, Oral↗