We investigated the relationship of the maxillary central incisors to the incisive papilla in wearers of complete dentures. First, image analyzer software was used to examine the relationship of the midpoint of the incisive papilla to the labial surface of the maxillary central incisors on occlusal photographs of 120 maxillary casts from dentate Malaysian adults. Then, an Alma denture gauge was used to identify the position of the labial surface of the maxillary central incisors in relation to the midpoint of the incisive papilla in complete dentures from 51 patients who requested replacement dentures at the Faculty of Dentistry, University of Malaya. The mean incisor distance to the incisive papilla in dentate adults was 9.59 ± 1.00 mm, while the mean incisor distance to the incisive papilla in complete dentures was 6.34 ± 1.87 mm. Thus, in our sample of edentulous patients, the anterior teeth in complete dentures were positioned approximately 3 mm closer to the incisive papilla, as compared with the position of the central incisors in natural dentition, and did not duplicate the position of the natural anterior teeth.
Standardized digital images of maxillary dental casts of 47 subjects were analyzed using MATLAB software whereby the two hamular notches and the incisive papilla defines the Cartesian vertical and horizontal axes, as well as the origin. The angle and length of the midpoints of the anterior teeth, mesiobuccal and distobuccal cusp of the posterior teeth were measured from the origin and denoted as θ(1), …, θ(18) and l(1), …, l(18) respectively. These values were collectively used to represent the shape of each dental cast. Clustering and principal component analyses were employed to find possible groups of dental arches using the above measure of shape. The main result of this study is that the 3 groups of dental arch shape may be represented by the novel feature vector v(k) = (θ(k)(1), l(k)(1), θ(k)(3), l(k)(3), θ(k)(5), l(k)(5), θ(k)(13), l(k)(13)), k = 1, 2, 3. Knowledge of v(k) implies three impression trays should be sufficient in a particular prosthetic dentistry application for Malaysian patients. Further, given that v(k) are accurately measured they may be potential candidates as evidence in specific application of forensic dentistry.
PURPOSE: The objective of this study was to test the hypothesis that fluoride-modified titanium surfaces would enhance osteoblast differentiation. Osteoblast growth on a moderately rough etched fluoride-modified titanium surface (alteration in cellular differentiation) was compared to osteoblast growth on the same surface grit-blasted with titanium dioxide. The potential role of nanometer-level alterations on cell shape and subsequent differentiation was then compared.
MATERIALS AND METHODS: Human embryonic palatal mesenchymal (HEPM) cultures were incubated on the respective surfaces for 1, 3, and 7 days, followed by analysis for cell proliferation, alkaline phosphatase (ALP) -specific activity, and mRNA steady-state expression for bone-related genes (ALP, type I collagen, osteocalcin, bone sialoprotein [BSP] II, Cbfa1, and osterix) by real-time polymerase chain reaction (PCR).
RESULTS: The different surfaces did not alter the mRNA expression for ALP, type I collagen, osterix, osteocalcin, or BSP II. However, Cbfa1 expression on the fluoride-modified titanium surface was significantly higher (P < .001) at 1 week. The number of cells on this surface was 20% lower than the number of cells on the surface TiO2-blasted with 25-microm particles but not significantly different from the number of cells on the surface TiO2-blasted with 125-microm particles. Cells grown on all the titanium surfaces expressed similar levels of ALP activity.
CONCLUSIONS: The results indicated that a fluoride-modified surface topography, in synergy with surface roughness, may have a greater influence on the level of expression of Cbfa1 (a key regulator for osteogenesis) than the unmodified titanium surfaces studied.
Selected landmarks from each of 47 maxillary dental casts were used to define a Cartesian-coordinate system from which the positions of selected teeth were determined on standardized digital images. The position of the i-th tooth was defined by a line of length (l(i)) joining the tooth to the origin, and the angle (θ(i)) of this line to the horizontal Cartesian axis. Four teeth, the central incisor, lateral incisor, canine and first molar were selected and their position were collectively used to represent the shape of the dental arch. A pilot study using clustering and principal component analysis strongly suggest the existence of 3 groups of arch shape. In this study, the homogeneity of the 3 groups was further investigated and confirmed by the Dunn and Davies-Bouldein validity indices. This is followed by an investigation of the probability distribution of these 3 groups. The main result of this study suggests 3 groups of multivariate (MV) normal distribution. The MV normal probability distribution of these groups may be used in further studies to investigate the issues of variation of arch shape, which is fundamental to the practice of prosthodontics and orthodontics.
The training of emergency medical officers has always been informal. Only recently, the presence of emergency physician may have a positive influence in their training and development. This study aims to determine the effect of Emergency Physician (EP) presence on the training exposure and confidence level of medical officers in their practice.
A cross-sectional survey of 400 medical students of multicultural backgrounds at the University of Malaya was conducted to understand their attitudes towards euthanasia and factors related to medical decisions and ethical reasoning concerning the prolongation of life, the right to die and euthanasia. The student respondents completed self-administered questionnaires that comprised of twelve questions with multiple stems addressing personal perceptions, knowledge, attitudes, and decisions about euthanasia and the relief of suffering. The majority of respondents (52%) were for the withdrawal of active therapy in a patient suffering from a terminal painful disease while 48% of them were against it. Seventy-one percent of the students involved in the study were against the idea of active euthanasia i.e. the administration of a lethal injection. However, 27% of the respondents felt that there was a moral justification to assist patients to die. Thirty-two percent of the respondents favoured the legalization of euthanasia in Malaysia while 67% of them were strongly against it. The majority (61%) of respondents would not practice euthanasia as a doctor nor would they have performed on themselves if or when it became legal. The main issue surrounding euthanasia that concerned the respondents was the misuse of it by unethical practitioners and they felt that further debate on the matter was essential, both within the local and international communities.
BACKGROUND: This study focused on the associations between socioeconomic status (SES) and adolescent smoking among secondary school students (13 to 17 years) in the Federal Territory of Kuala Lumpur, Malaysia. Our objective was to evaluate the relationships between adolescent demographics, socioeconomic status and smoking status.
METHODS: The survey data were based on baseline findings from a cross-sectional study (N = 422 adolescents). Chi-square test was used to assess the relationship between demographic characteristics, socioeconomic status (household monthly income and daily allowance) and adolescent smoking status. Exhaled carbon monoxide (CO) reading and the Hooked on Nicotine Checklist (HONC) were used to evaluate adolescent smoking status. A Multivariate Multinomial Logistic Regression (MMLR) was employed to test selected demographic and socioeconomic predictors of smoking status.
RESULTS: Of the 422 adolescents (M age = 15.58, SD = 1.24), more than half of the participants initiated smoking between 13 to 17 years old (59.0%). A total of 308 (73.0%) were electronic cigarette users, with more than 50% comprising of single users. The mean CO reading was 2.14 ppm with 78.0% of adolescents scoring more than 0 on the Hooked on Nicotine Checklist (HONC). Males and participants aged 15 and 16 years were at increased risks of sole CC smoking. Meanwhile, males, those who are not hooked on smoking and with a non-smoker CO reading were at increased risks of sole EC smoking. Finally, Bumiputeras were at less risk of EC smoking.
CONCLUSIONS: Demographic variables such as age, gender and ethnicity predicted smoking status predicted smoking risk, but not socioeconomic factors. The findings allow policy makers to target specific high-risk demographic groups when designing smoking cessation programs for adolescents.