[Report of 145 modified adhesive fixed bridges after reexamination.].
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
S H Wei
Publications and source records attributed to S H Wei.
A method for microleakage evaluation along the dentin/restorative interface.
PURPOSE: To present a simple non-abrasive protocol in conjunction with the silver-staining method, enabling unobstructed visualization of well-defined microleakage patterns within the demineralized dentin-restorative interface. MATERIALS AND METHODS: Class V preparations were made with an occlusal margin on bevelled enamel and a gingival margin on dentin/cementum. After restoration with All Bond 2/P-50 and Scotchbond 2/Silux, storage in water at 37 degrees C for 7 days and thermocycling 300 times between 5 degrees and 55 degrees C, the specimens were placed in silver nitrate solution. After silver fixation, demineralization and clearing in methyl salicylate, silver stain location was scored ordinally. In addition, a three dimensional portrait of leakage pathways was illustrated using photographic and computer digitization. RESULTS: The Wilcoxon signed-rank test showed that the extent of silver penetration before and after acid demineralization was not significantly different (P > 0.05). This study also confirmed that microleakage is not uniform along the circumference of a restorative margin. Although the protocol is insensitive to microleakage occurring solely within enamel, the predominant concern over that occurring within dentin, in particular along the cervical restorative border, renders it a serviceable alternative for future investigation of the integrity of the marginal seal from clinically restored in vivo specimens.
Acid Etching, Dental↗
The knowledge and attitude of Hong Kong secondary school teachers and students towards HIV infection and dentistry.
Although human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) are firmly entrenched in Hong Kong no data are available on the knowledge and attitudes of Hong Kong secondary school teachers and teenage children towards this infection, and their perception of infection control measures currently undertaken by the dental profession to prevent such infectious diseases. Hence a postal questionnaire survey of a total of 2,886 teenagers and 372 school teachers of 21 secondary schools in Hong Kong was conducted. The questionnaire comprised a total of 13 questions divided into two categories; the first, aimed at assessing the respondents' general knowledge and attitudes towards AIDS, and the second related to AIDS, dentistry and infection control. More than half of the students and one quarter of the teachers surmised that HIV infection is equivalent to developing AIDS. Although the great majority of the respondents (85-97 per cent) were aware that HIV can not be transmitted through sharing combs and meals, one in two teachers and one in three students thought that the virus could be transmitted through saliva. A large majority of respondents believed television to be the most, and dentists the least, informative source on AIDS out of a list of eight options. Approximately one half of both groups were concerned about contracting HIV infection during dental treatment and 65 per cent of students and 57 per cent of teachers thought that dentists did not have sufficient knowledge to identify AIDS patients. Finally, more than three quarters of the respondents thought that it would be ill-advised to visit a dentist treating HIV-infected patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Acquired Immunodeficiency Syndrome↗
Expression cloning and characterization of a human IL-10 receptor.
cDNA clones encoding a human IL-10R (hIL-10R) from a Burkitt lymphoma cell line, BJAB, express a 90 to 110 kDa polypeptide in COS7 cells that binds hIL-10 specifically. The predicted amino acid sequence of hIL-10R is 60% identical and 73% similar to mouse IL-10R (mIL-10R). rIL-10R expressed in an IL-3-dependent mouse pro-B cell line (Ba/F3) binds hIL-10 with high affinity (200 to 250 pM), and the transfected cells exhibit a proliferative response to hIL-10. Mouse IL-10 does not bind to hIL-10R, and hIL-10R-expressing Ba/F3 cells do not respond to the mouse cytokine, observations consistent with the known species specificity of IL-10. Expression of hIL-10R mRNA seems to be restricted mainly to human hemopoietic cells and cell lines. In a number of human T cell clones, expression of hIL-10R mRNA is down-regulated after activation of the cells with anti-CD3 Ab and phorbol ester. The hIL-10R gene is on human chromosome 11. Like mIL-10R, hIL-10R is structurally related to IFNR. Because IL-10 inhibits macrophage activation by IFN-gamma, this relationship suggests possible shared receptor or signal transduction pathway components.
Amino Acid Sequence↗
Structural evidence of a sealed tissue interface with a total-etch wet-bonding technique in vivo.
The resin-dentin interface of in vivo specimens restored with the All-Bond 2 system by use of a total-etch wet-bonding technique on vital deep human dentin was investigated by: (a) SEM examination of cryofractured specimens; (b) SEM examination of acid-rinsed, highly polished, embedded specimens; and (c) TEM examination of demineralized ultrathin sections. Ultrastructural features that were pertinent to the formation of an effective clinical seal were characterized. It is suggested that the establishment of an effective seal of the patent dentinal tubules following total etching is accomplished by: (1) the formation of an outer zone of a solid resin plug surrounded by a circumferential cuff of resin-impregnated dentin; and (2) the formation of an inner zone of a hollow resin sheath with resin globules along the internal walls of the tubules, closely adapting to the odontoblast process. The structural appearance and functional implications of these two zones were strikingly similar, with the sealing of exposed dentinal tubules in arrested carious lesions or cervical abfraction lesions. It appeared that there is a common denominator in physiologic isolation defense mechanisms and the total-etch, wet-bonding technique in the All-Bond 2 system in preserving the biological and morphological integrity of the pulpo-dentinal complex.
Acid Etching, Dental↗
[Complicated cataract after vitrectomy and gas-liquid exchange].
Cases with complicated cataract occurring after vitrectomy and gas-liquid exchange were reported. In a consecutive series of 62 eyes having undertaken the operation, a transient cataract developed in 8 eyes and an irreversible cataract in 28 eyes. The manifestation of the transient cataract is the posterior subcapsular opacity, feathery or placoid vacuolar in clusters in appearance. It was found that if the amount of the residual vitreous at the retrolental space is great enough, the chance of occurrence of complicated cataract is less. That the direct contact of the gas with the lens affects the lens metabolism and nutrition is the chief cause of the development of the cataract. It is suggested that to prevent the development of cataract induced by the gas, besides selection of body posture, quiet stay in bed and proper selection of gas type, the vitreous at retrolental space be resected as little as possible.
Adolescent↗
Esthetic treatment of severe tetracycline staining with orthodontics and veneers: a case report.
This case history describes and illustrates the excellent esthetic results now clinically possible when fixed appliance orthodontic therapy is combined with porcelain veneers to treat severe tetracycline staining and crowding. Because the patient also presented with a bimaxillary protrusion and a displaced maxillary midline, the treatment options also illustrate the dilemma between ideal, but prolonged, treatment options and quicker, but compromised, alternatives. The excellent final result accepted the initial protrusion but corrected the midline. A long-span bonded multistrand wire functioned as semipermanent retention.
Adult↗
Enhancement of renal and hepatic glutathione metabolism by dimethylthiourea.
Dimethylthiourea (DMTU), a free radical scavenger, was administered to rats to study its effect on renal and hepatic glutathione metabolism, since it is a potential sulfhydryl donor. Six hours following DMTU, renal GSH content was significantly (P < 0.05) increased (10%), and was increased further after 24 h (28%) (P < 0.001). Hepatic GSH content was also significantly (P < 0.001) elevated at 6 and 24 h (5 and 33%, respectively). Seven days of daily DMTU therapy significantly (P < 0.001) increased renal and hepatic GSH content by 36 and 54%, respectively, which was associated with a significant (P < 0.001) increase in the renal activities of glutathione peroxidase (GP) by 38%, glutathione transferase (GT) by 92%, and glutathione reductase (GR) by 19% (P < 0.05). Significantly increased activities of hepatic GP by 84% (P < 0.01) and GT by 101% (P < 0.001) also occurred in DMTU-treated rats after 7 days of continuous therapy. From these data, we conclude that DMTU stimulates renal and hepatic GSH metabolism, which may be important in mediating DMTU's protective effect against free radical-induced tissue injury.
Animals↗
Recording and measuring malocclusion: a review of the literature.
The methods of recording and measuring malocclusion can be broadly divided into two types: qualitative and quantitative. Among the qualitative methods of recording malocclusion, Angle's method of classifying malocclusion with or without modifications is probably the most widely used. The "WHO/FDI Basic Method for Recording of Malocclusion" was published in 1979 to establish an assessment format to determine the prevalence of malocclusion and to estimate treatment needs of a population. Among the many occlusion indices developed by various research workers, the occlusal index developed by Summers appeared to have the least amount of bias, is best correlated with clinical standards and has the highest validity during time. More recently, methods have also been developed to enable assessment of treatment need according to grade index scales. However, experience in using these methods is still very limited.
Humans↗
Evaluation of the use of topical fluoride gel.
Professionally applied topical fluoride should be used judiciously and is indicated only in patients with moderate or high caries activity. While the anti-caries effectiveness of acidulated phosphate fluoride gels has been clinically documented, the 2% neutral NaF gel has not been adequately tested, and further clinical verification is needed. Daily use of a self-applied fluoride gel is recommended for patients undergoing orthodontic treatment or to those affected with xerostomia as a result of disease or head and neck radiation therapy. The dental profession and the public should be well informed on the proper use of clinically proven products to achieve optimum effectiveness and minimize the risk of fluoride ingestion.
Acidulated Phosphate Fluoride↗
The effects of etching, micro-abrasion, and bleaching on surface enamel.
Conservative techniques for improving the appearance of discolored teeth have become popular in the past decade. These include: in-office bleaching with 30% hydrogen peroxide, which is applied on etched enamel with a gauze pad and then exposed to a bleaching light; home bleaching with a mild form of peroxide, such as 10% carbamide peroxide, which is applied on the tooth surface with custom-made mouthguards; and enamel micro-abrasion with 18% hydrochloric acid, which is applied in a pumice slurry. In this study, the in-office bleaching and enamel micro-abrasion techniques were performed on extracted teeth for investigation of their microscopic effects on the surface enamel. Specimens treated only with 37% phosphoric acid showed an enamel loss of 5.7 +/- 1.8 microns. The specimens treated with 37% phosphoric acid followed by 30% hydrogen peroxide showed enamel loss of 5.3 +/- 1.6 microns; this loss was probably not caused by the hydrogen peroxide, but rather by the etching with 37% phosphoric acid which preceded the hydrogen peroxide application. A direct application of 18% hydrochloric acid for 100 s resulted in a loss of 100 +/- 47 microns. The extent of enamel loss was much greater when the 18% hydrochloric acid was applied in a pumice slurry for the same period of time (360 +/- 130 microns), and the effect was time-dependent. Thus, the pumice and rotary prophy cup used in conjunction with the 18% hydrochloric acid contributed markedly to the loss of surface enamel, enhancing the non-selective stain-removing action of the hydrochloric acid. Therefore, the hydrochloric acid-pumice technique must be used clinically with caution.
Acid Etching, Dental↗
Three-dimensional joint range of motion measurements from skeletal coordinate data.
Frequently, joint range of motion is reported for a single plane (eg., sagittal, coronal, or transverse). However, the arc of joint motion during functional activities and many clinical tests encompasses motion in all three planes simultaneously. The purposes of this paper are to discuss a method to obtain relative joint three-dimensional angular displacement measurements using coordinates from skeletal landmarks and provide an analytical example of the method using three-dimensional angular displacement of the knee joint as a model. In order to calculate the three-dimensional relative motion, an orthogonal reference frame for each bone needs to be established. To establish the local reference frame, three noncollinear points are used to define unit vectors that are mutually perpendicular. Three-dimensional angles can be determined to describe the magnitude of the moving body rotation angles about the X, Y, and Z axes. These angles indicate the relative motion of body segments for abduction/adduction, flexion/extension, and internal/external rotation. The technique provides a more vigorous biomechanical understanding of joint motion and may have implications for measuring patient progress and evaluating joint mobilization treatment. This technique may also serve as a basis for developing new evaluation and treatment techniques.
Biomechanical Phenomena↗
Mouthrinses: recent clinical findings and implications for use.
Fluoride mouthrinses have been used extensively for the past 15 years to prevent dental caries in children. It has been demonstrated to reduce the incidence of dental caries in children by an average of 30 per cent. For individual patients, dentists should continue to recommend fluoride mouthrinsing at home, based upon the individual's caries activity or risk. This is true whether or not the patient is also receiving the benefits of community water fluoridation. School-based fluoride mouthrinsing programmes are recommended only in fluoride-deficient communities. Its effectiveness will be determined by the caries activity of the participants and the cost to reduce the disease level to an anticipated 30 per cent. Among all the topical fluoride agents, fluoride mouthrinses remain a safe and effective means of controlling dental decay in children and adolescents.
Dental Caries↗
Clinical efficacy of dentifrices in the control of calculus, plaque, and gingivitis.
Several dentifrices are available in the market for the control of calculus, plaque, and gingivitis. The anticalculus activity of the pyrophosphate dentifrice formulation has been convincingly demonstrated. Recently, dentifrices containing 0.3% triclosan and 2.0% Gantrez have been shown to possess some anticalculus activity, in addition to their antiplaque and antigingivitis properties. Similarly, sequential application of sanguinarine-containing dentifrice with a brush, followed by a rinse of 30 to 60 seconds, also provides sustained antiplaque and antigingivitis effects. However, other dentifrices have had much less convincing clinical results. It is therefore important for dentists to interpret the therapeutic claims of various antiplaque and antigingivitis dentifrices cautiously before recommending these products to patients.
Alkaloids↗
Glutathione monoethyl ester moderates mercuric chloride-induced acute renal failure.
Glutathione (GSH)-dependent reactions are an important cellular defense against ischemic or oxidative injury, although their role in toxin-induced renal cellular injury is less clear. Because of the known sulfhydryl reactivity of mercury (M), we hypothesized that GSH could modify mercuric chloride (MC)-induced acute renal failure (ARF). Therefore, we evaluated the effects of glutathione monoethyl ester (GE), which produces high intrarenal levels of GSH, on the nephrotoxicity of MC. GE treatment in normal rats did not alter their creatinine clearance (CCr), fractional sodium (CNa/CCr) or lysozyme (CLy/CCr) excretion, but histologically resulted in prominent proximal tubular vacuolization. GE pretreatment in rats with MC-induced ARF resulted in partial preservation of their CCr, CNa/CCr and CLy/CCr. Renal histology also demonstrated a reduction in tubular necrosis. M content in the renal cortex 3 following MC was lower in the MC + GE group, but levels were higher in the liver and inner stripe/inner medulla as compared to animals receiving MC alone. No differences were seen in the outer stripe at 3 h or in any of the tissues 24 h following MC injection. Thus, GE moderated MC-induced ARF, likely by providing a large intracellular sulfhydryl pool and thereby reducing M reactivity with endogenous cellular proteins and enzymes.
Acute Kidney Injury↗
Role of glutathione metabolism in the reduction of proteinuria by dimethylthiourea in adriamycin nephrosis.
Glutathione (GSH) metabolism, a tissue detoxification pathway, was evaluated in rats with adriamycin nephrosis (AN) treated with dimethylthiourea (DMTU), a free radical scavenger. After 7 days of DMTU, a significant reduction in proteinuria occurred as compared to AN controls (62.4 +/- 13.3 vs. 155.0 +/- 24.0 mg/24 h). A significant increase in renal cortical GSH content as well as glutathione peroxidase (GP) and transferase (GT) activities occurred in DMTU-treated rats as compared to controls. Glutathione monoethyl ester (GME) administration alone reduced proteinuria by 21% in AN, which was not significant despite a large increase in the renal GSH content, however, GP and GT activities were not increased by GME. We conclude that DMTU ameliorates glomerular injury in AN by stimulating GSH metabolism.
Animals↗
Treatment of Class II open bite in the mixed dentition with a removable functional appliance and headgear.
Early diagnosis of patients exhibiting open bites that are complicated by skeletal Class II and vertical growth problems can facilitate subsequent treatment. Eight patients with Class II skeletal open bite were treated with the high-pull activator appliance and compared to reasonably matched controls to determine the effects of the appliance. The high-pull activator was found to reduce forward growth of the maxilla and increase mandibular alveolar height, transforming the Class II molar relationship into a Class I molar relationship. The overjet and open bite were decreased, and, in addition, the appliance reduced the amount of forward and downward movement of the maxillary molars, providing vertical control of the maxilla during Class II orthopedic correction. These results demonstrated that open bite complicated by a Class II vertical growth pattern can be treated during the mixed dentition with favorable results by a combination of a removable functional appliance and high-pull headgear.
Activator Appliances↗
Management of rampant caries in children.
Because research has resulted in a better understanding of the etiology of dental caries as well as the introduction of new techniques and materials in the practice of dentistry, approaches toward the management of rampant caries should be reevaluated. The development of the acid-etching technique and the improvements in the physical properties and clinical performance of composite resins and glass-ionomer cements have completely changed the concepts of prevention, conservative dentistry, and dental esthetics. Several methods for the treatment of rampant caries are described and management of two cases is documented.
Acute Disease↗