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Biomedical subjects

I Punwani

Publications and source records attributed to I Punwani.

At least 19 recordsLinked to original sources
PubMed2000

Sealant bond strengths of CO(2) laser-etched versus acid-etched bovine enamel.

BACKGROUND AND OBJECTIVE: The purpose of this study was to evaluate sealant shear bond strength on bovine enamel with standard acid etching compared with CO(2) laser etching. STUDY DESIGN/MATERIALS AND METHODS: Bovine enamel was prepared either by acid or laser etching and divided into four experimental groups, either acid or laser-etched teeth with or without a primer. A gelatin capsule was used to place the sealant on the prepared enamel surface and the bond tested in shear. Also surface roughness was evaluated by using a surface analyzer and an atomic force microscope. RESULTS: Shear bond strength results were the following: acid etch = 8.8 +/- 3.8 MPa, acid etch with primer = 10.3 +/- 5.5 MPa, laser etch = 4.0 +/- 1.1 MPa, and laser etch with primer = 6.2 +/- 2.3 MPa. Analysis of variance statistical analysis found no significant difference in bond strength between the acid-etched groups. However, the laser-etched groups had significantly lower bond strengths from the acid-etched teeth. In addition, a significant difference was observed between the laser-etched groups, where the use of the primer helped to increase the bond strength of the sealants. The surface roughness was significantly greater on the laser-etched teeth at the microm level (by using a surface analyzer) from the acid-etched and the control specimens. No difference in roughness (by using an atomic force microscope) was observed at the nanometer level between the laser and acid-etched teeth. CONCLUSION: For these particular settings, the laser-etched teeth resulted in lower bond strengths to enamel and the use of a primer increased the bond strength for laser-etched teeth only.

Acid Etching, Dental↗
PubMed1998

Bond strength of Bis-GMA and glass ionomer pit and fissure sealants using cyclic fatigue.

The aim of the study was to determine the bond strength of glass ionomer and resin-modified glass ionomer sealants compared to Bis-GMA sealants using both static and cyclic fatigue shear testing. Four materials were evaluated: D, a Bis-GMA sealant with 10% phosphoric acid etchant; FC, a resin-modified glass ionomer sealant with 20% polyacrylic acid etchant; FD, a resin-modified glass ionomer sealant with 10% polyacrylic acid etchant; and FSC, a self-cured glass ionomer sealant with no etchant. Gelatin capsules filled with the sealant material were bonded to the enamel surfaces of bovine teeth after appropriate surface conditioning and then tested in shear static and cyclic fatigue. Static and cyclic shear bond strengths, respectively, for each group were (MPa): FC: 21.1+/-2.8 and 17.1+/-3.1; FD: 14.6+/-5.9 and 8.5+/-3.1; D: 10.8+/-4.9 and 4.7+/-2.6; FSC: 8.7 (1.0 and 2.9+/-0.6. The resin-modified glass ionomer sealants had better fatigue bond strength than both Bis-GMA and self-cured glass ionomer sealants with the surface conditioning affecting the bond strength of the resin-modified glass ionomer sealants.

Acid Etching, Dental↗
PubMed1991

Analysis of neutrophil chemotaxis and CD11b expression in pre-pubertal periodontitis.

The objectives of this study were to (1) determine chemotaxis (CX) response by neutrophils (PMNs) isolated from patients with the localized form of pre-pubertal periodontitis (L-PP) and compare these responses with those of age-matched and adult controls, (2) determine the level and up-regulation of CD11b expression upon stimulation with fMLP by peripheral blood PMNs (PB-PMNs) isolated from patients with L-PP and compare these levels with those of age-matched and adult controls, and (3) determine whether there is a correlation between CX and CD11b expression (up-regulation) by PB-PMNs. PB-PMNs from a total of seven patients with L-PP, seven age-matched pediatric controls, and 11 adult controls (four adults for both CD11b and CX assays, and seven adults for CX assays only) were analyzed for CX and CD11b expression. Direct immunofluorescence staining of CD11b was performed with FITC-conjugated monoclonal antibody. Flow cytometry was used to analyze stained cells for their fluorescence intensity. Chemotaxis activity in response to 10(-8) mol/L fMLP was examined in micro-well chemotaxis chambers. The results indicated that CX of PMNs from both L-PP patients and pediatric control subjects was significantly decreased, compared with that of normal adult control subjects (p less than 0.001). There was no significant difference between CX of PMNs from L-PP patients and that from normal pediatric controls (p greater than 0.7). CD11b expression did not significantly differ among L-PP patients, normal pediatric controls, and adult controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Use of a palatal stabilizing device in prevention of palatal grooves in premature infants.

A prospective, randomized study using an acrylic palatal stabilizing device (PSD) was conducted to evaluate the effectiveness of this device in preventing disruptions in palatal architecture. A total of 26 premature infants with birth weights of 540 to 1740 g, and intubated orally for a period varying from 7 to 109 days were randomized to control and experimental groups. All neonates in the control group developed palatal grooving ranging from 2 to 5 mm in depth, whereas those in the experimental group (with a PSD) showed no evidence of palatal grooving. We conclude that a PSD is an effective preventive device in premature orally intubated infants.

Dental Impression Technique↗
PubMed1986

Interface corrosion in amalgam-to-amalgam and amalgam-to-nonprecious metal crown couplings.

This study examined the contact surface area in the coupling of a class II amalgam restoration with another class II amalgam restoration or with a stainless steel or nickel-chrome crown in 1% NaCl solution. The characterization of interfaces was carried out by using SEM and EDX microanalysis. The results indicate that the coupling of an amalgam-stainless steel crown and an amalgam-inconel crown in NaCl solution forms a deposit on the crown surfaces. This deposit contains all the constituents of corrodible phases of amalgam, including Zn. If amalgam restorations in adjoining teeth are contemplated, non-Zn-containing amalgam alloys of the same composition should be considered.

Chemical Phenomena↗
PubMed1984

Contamination of dental unit cooling water with oral microorganisms and its prevention.

Each time the handpiece turbine is stopped while the bur is still in the patient's mouth, almost 1 ml of microbe-laden oral fluids may be aspirated into the average dental unit water line by the retraction valve present in the dental unit. This fluid may contain an average in excess of 54,000 microorganisms per milliliter, including both facultative and obligate anaerobic bacteria of medium to high virulence. Other infectious agents including hepatitis, herpes, influenza, and other upper respiratory viruses may also be present. This germ-laden water may then be sprayed into the mouth of the next patient, possibly initiating an oral or upper respiratory tract infection. Sterilizing the handpiece between appointments, although of great significance in the prevention of disease transmission, will not totally eliminate the problem discussed here as almost 95% of the oral fluid aspirated into the dental unit went past the handpiece and into the handpiece cooling water line. Complete elimination of the retraction valve in the unit is the most effective means of solving this problem, but, with present dental unit designs, this may result in water dripping onto the patient. A viable alternative is the installation of a check valve (anti-retraction valve) downstream from the retraction valve. Installation of a check valve resulted in an almost 4,000-fold decrease in this contamination. The attachment of a check valve will have no effect on normal less virulent bacteria already present in tap water. These bacteria colonize the water lines of the dental unit and are then continually shed into the water in numbers often as high as 1,000,000 CFU/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Phase contrast microscopy of microbial aggregates in the gingival sulcus of Macaca mulatta. Subgingival plaque bacteria in macaca mulatta.

The objective of this study was to study the relationship of microbial aggregates in the subgingival crevice to changes in periodontal health in Macaca mulatta. The sample included 68 oral sites from 17 Rhesus monkeys of various ages. The periodontal health of each site was evaluated using Plaque and Gingival Indices and crevice depth measurement. The subgingival plaque samples were examined by phase contrast microscopy and recorded on 16 mm film. A Microbial Index was developed based on a qualitative estimate of the numbers of organisms, morphology of predominant organisms, and the presence or absence of motility. The Microbial Index was demonstrated to be simple in use and highly reproducible. The findings indicate that changes in the Microbial Index are consistent with tissue changes seen in the periodontal status in M. mulatta. From this preliminary study, the oral flora of adult M. mulatta appears to have sufficient similarities to human oral flora to be used as a microbial model for experimental periodontal disease research. Future studies to refine and confirm the validity of the Microbial Index are warranted. It may prove to be a useful tool to monitor the effect of various treatment modalities on the periodontal flora and to determine the presence or absence of active disease.

Animals↗