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Biomedical subjects

F C Chu

Publications and source records attributed to F C Chu.

100 records · Page 6Linked to original sources
PubMedDate not supplied

Intraocular pressure and hemodynamic changes following tracheal intubation in children.

STUDY OBJECTIVE: To determine the optimal time in which to make intraocular pressure (IOP) measurements in children following tracheal intubation. DESIGN: Randomized, controlled trial. SETTING: Operating rooms of a tertiary-care children's hospital. PATIENTS: Thirteen healthy children undergoing elective strabismus correction surgery under halothane and nitrous oxide (N2O) endotracheal anesthesia. INTERVENTIONS: Following induction of anesthesia, patients were randomly assigned to receive stable end-tidal halothane concentrations of 0.5% or 1.0% in 66% N2O. MEASUREMENTS AND MAIN RESULTS: Baseline (preintubation) IOP, heart rate (HR), and mean arterial pressure (MAP) were recorded after 10 minutes of steady-state end-tidal concentrations. These measurements were repeated at 1-minute intervals following tracheal intubation, which was facilitated with atracurium. HR and MAP changes were found to be good predictors of IOP changes. IOP returned to baseline (preintubation) values when HR and MAP returned to preintubation levels. However, IOP measurements under anesthesia may not reflect awake values. CONCLUSIONS: We recommend that IOP be measured only after HR and MAP have returned to preintubation levels in children who have undergone tracheal intubation during halothane and N2O anesthesia.

Anesthesia, Endotracheal↗
PubMedDate not supplied

Selection of restorative materials for the atraumatic restorative treatment (ART) approach: a review.

The atraumatic restorative treatment (ART) technique or approach for the restoration of primary and permanent teeth has been widely adopted in, but not limited to, developing countries. However, the requirement for the placement of the restorative materials under often less-than-ideal conditions imposes significant restrictions on their selection; and there have been very few randomized clinical trials or reports comparing different types of restorative materials and treatments. Although conventional glass-ionomer cements (GICs) have relatively poor mechanical and adhesive strengths, their satisfactory biological features, ease of use, and low costs are distinct advantages. Most of the published reports of the clinical performance of the newer, high-strength esthetic conventional GICs specifically marketed for the ART approach have been from short-term studies. Satisfactory clinical performance has been demonstrated for single-surface posterior restorations only, over three years. Findings indicate that further improvements in restorative materials are still required for their use with the ART approach, together with further clinical investigations of the remineralization of shallow open caries lesions, as an alternative to placing definitive restorations.

Cariostatic Agents↗
PubMedDate not supplied

Habitual head turning in spasmus nutans: an oculographic study.

Head turning in patients with spasmus nutans seems to transiently dampen the nystagmus. This was evident in two children by clinical observation and electrooculographic recording. The suppression of the nystagmus may have been mediated by the vestibular system.

Child, Preschool↗
PubMedDate not supplied

Sensory strabismus--eso or exo?

PURPOSE: The type of horizontal strabismus from loss or impairment of vision is thought to depend on patient age at the time of vision loss. Association between the age at onset of vision loss and development of esotropia vs exotropia will be determined. METHODS: Patients with a diagnosis of sensory strabismus and visual acuity of 20/40 or poorer were reviewed as well as patients with diagnoses consistent with the development of sensory strabismus. Parameters considered were age at onset of vision loss and type of strabismus. Patients were excluded if the age at onset was not clear. RESULTS: Of 123 patients with sensory strabismus reviewed: 82 (67%) had unilateral vision loss; 41 (33%) had bilateral vision loss; 75 (61%) had congenital vision loss; 50 (67%) developed esotropia; 25 (33%) developed exotropia; 48 (39%) had acquired vision loss; 5 (10%) developed esotropia; and 43 (90%) developed exotropia. A significant difference was noted between age at onset and type of horizontal strabismus (X2= 37.44; P <.0001). CONCLUSION: Of patients with congenital vision loss, 67% developed sensory esotropia and 33% developed sensory exotropia. Of those with acquired vision loss, 10% developed sensory esotropia and 90% developed sensory exotropia. Patients with congenital vision loss are significantly more likely to develop esotropia, P <.005, and those with acquired vision loss are significantly more likely to develop exotropia, P <.001.

Age of Onset↗
PubMedDate not supplied

Surface roughness and flexural strength of self-glazed, polished, and reglazed In-Ceram/Vitadur Alpha porcelain laminates.

PURPOSE: Because of existing controversy, the present study investigated 3 methods for reducing surface roughness and improving the strength of porcelain restorations. MATERIALS AND METHODS: Ninety laminated In-Ceram/Vitadur Alpha self-glazed porcelain disks were fabricated and randomly divided into 3 groups (n = 30 each). Group 1 consisted of 30 of the original disks. The remaining 60 disks were then polished by 6 operators according to the recommendations of the American Academy of Esthetic Dentistry; group 2 consisted of 30 of these polished disks. The remaining 30 polished disks were reglazed (group 3). Average roughness values (Ra) of the veneers were measured by a profilometer. In each group, 20 disks were subjected to a flexure test, with 10 of the In-Ceram cores and 10 of the Vitadur Alpha veneers placed in tension. RESULTS: The Ra values were 0.5 +/- 0.1 micron, 0.7 +/- 0.3 micron, and 0.4 +/- 0.1 micron for groups 1 to 3, respectively. Following one-way analysis of variance (ANOVA), Bonferroni's multiple comparison tests found that groups 1 and 3 were significantly smoother than the polished group (P < 0.001). Reglazed disks were also significantly smoother than the original self-glazed disks (P < 0.01). With the veneers in tension, the flexural strengths were 151 +/- 22 MPa, 118 +/- 22 MPa, and 172 +/- 27 MPa for group 1 to 3, respectively. Following one-way ANOVA, Bonferroni's multiple comparison tests found that groups 1 and 3 were similar and were significantly stronger than the polished samples (P < 0.05 and P < 0.001). CONCLUSION: Reglazing polished porcelain surfaces significantly improved the surface texture and flexural strength of the materials tested.

Algorithms↗
PubMedDate not supplied

Fracture behavior of human mandibular incisors following endodontic treatment and porcelain veneer restoration.

PURPOSE: Because of existing controversy, the present study investigated the individual and combined effects of endodontic treatment and porcelain veneer restoration on the fracture behavior of human mandibular incisors. MATERIALS AND METHODS: Forty extracted intact human mandibular incisors were assigned to four groups of ten with a similar range of labiolingual widths at the cementoenamel junctions. Group A consisted of intact teeth; group B consisted of endodontically treated teeth; group C teeth were restored with labial porcelain veneers; and those of group D were endodontically treated and had labial porcelain veneers. All teeth were subjected to a slow continuous loading test at 30 degrees to the long axis of the teeth and 1 mm below the incisal edge on the labial side. RESULTS: Fracture forces were 415 +/- 220 N, 370 +/- 89 N, 420 +/- 128 N, and 448 +/- 156 N for groups A, B, C, and D, respectively. Root fracture was the most common mode of failure. There were no statistically significant differences between the groups in terms of fracture forces and modes of failure. CONCLUSION: Human mandibular incisors with endodontic treatment and/or porcelain veneer restorations were able to withstand the same magnitude of oblique loading as intact teeth. Endodontic treatment and/or porcelain veneer restoration did not affect the mode of failure of mandibular incisors.

Acid Etching, Dental↗
PubMedDate not supplied

Management of median diastema.

In mixed and early permanent dentitions, median diastema can be a major esthetic concern for patients and/or their parents. The space can be transient or created by developmental, pathological, or iatrogenic factors. Different treatment techniques have been proposed to manage the situation. This paper reviews the common causes of median diastema and presents four cases to illustrate a range of restorative and orthodontic options.

Adolescent↗