Biomedical subjects

M L Barker

Publications and source records attributed to M L Barker.

4 recordsLinked to original sources

PubMed2001

Effects of a tartar control whitening dentifrice on tooth shade in a population with long-standing natural stain.

Changing and whitening tooth color in people with long-standing tooth stain without excessive hard tissue abrasion may represent one of the more difficult challenges for whitening dentifrices. An eight-week clinical trial was conducted to evaluate change in tooth color by a silica-based, enamel-safe tartar control whitening dentifrice compared to a marketed baking soda dentifrice control. First, a screening exercise was conducted to identify individuals with long-standing extrinsic dental stain. This exercise targeted adults who reported "stained teeth" and coffee/tea drinking or smoking, but who had no recent history of dental prophylaxis. Targeted subjects were examined for stain (Lobene Index) and tooth shade/color (Vita). A total of 291 adults having extrinsic stain and discolored teeth were enrolled in the study. Subjects were randomized to one of the two treatment groups, and all dentifrice use was unsupervised. Tooth color was measured at 4 and 8 weeks from shade values collected from the 8 incisors, and averages were determined from a linear ordering of the shade guide. A total of 278 evaluable subjects completed the 8-week study. Overall, the tartar control whitening dentifrice group experienced an improvement in color, differing statistically from baseline (p < 0.001) and from the marketed control (p < 0.05). Safety profiles for the two dentifrices were generally similar. Among patients with long-standing extrinsic stain, use of the tartar control whitening dentifrice resulted in superior overall tooth shade and reduced maximum or worst color compared to the marketed baking soda dentifrice control.

Adult↗

PubMed2001

Comparative efficacy and tolerability of two direct-to-consumer tooth whitening systems.

PURPOSE: To compare the clinical response of two self-directed vital bleaching systems under market use conditions. MATERIALS AND METHODS: A randomized, parallel-group clinical trial was conducted. A total of 20 healthy adults were randomized to either a 6.0% hydrogen peroxide strip-based bleaching system or a combination system involving a 10% carbamide peroxide gel in a stock tray along with an anticavity whitening dentifrice and after-bleaching whitening mouthrinse. Only the maxillary arch was bleached over a 14-day period. Subjects were evaluated at 3, 8 and 15 days. Efficacy was measured objectively using digital image analysis to derive individual color parameters (L*a*b*) and overall color change (deltaE*). RESULTS: After 14 days, the adjusted mean reduction in yellow (Ab*) was -2.23 +/- 0.157 for the whitening strips compared to -0.97 +/- 0.188 for the combination system. This represented a highly statistically significant (P< 0.0001), two-fold superior reduction in yellowness for the whitening strip group compared to the marketed control. Similar results were seen for other color parameters, with the whitening strip group exhibiting two-fold color improvement relative to the tray/dentifrice/rinse combination. With respect to tolerability, tooth sensitivity and oral irritation were the most common findings. Considering event duration and severity, median bleaching tolerability severity-days scores were 0.07 and 0.58 for the strip and combination systems respectively, with these treatments differing statistically (P= 0.04 1) favoring the whitening strips.

Adult↗

PubMed1999

Adenosine myocardial protection: preliminary results of a phase II clinical trial.

OBJECTIVE: To evaluate the safety, tolerance, and efficacy of adenosine in patients undergoing coronary artery bypass surgery. SUMMARY BACKGROUND DATA: Inadequate myocardial protection in patients undergoing coronary artery bypass surgery contributes to overall hospital morbidity and mortality. For this reason, new pharmacologic agents are under investigation to protect the regionally and globally ischemic heart. METHODS: In a double-blind, placebo-controlled trial, 253 patients were randomized to one of three cohorts. The treatment arms consisted of the intraoperative administration of cold blood cardioplegia, blood cardioplegia containing 500 microM adenosine, and blood cardioplegia containing 2 mM adenosine. Patients receiving adenosine cardioplegia were also given an infusion of adenosine (200 microg/kg/min) 10 minutes before and 15 minutes after removal of the aortic crossclamp. Invasive and noninvasive measurements of ventricular performance were obtained before, during, and after surgery. RESULTS: The high-dose adenosine cohort was associated with a trend toward a decrease in high-dose dopamine support and a lower incidence of myocardial infarction. A composite outcome analysis demonstrated that patients who received high-dose adenosine were less likely to experience one of five adverse events: high-dose dopamine use, epinephrine use, insertion of intraaortic balloon pump, myocardial infarction, or death. The operative mortality rate for all patients studied was 3.6% (9/253). CONCLUSIONS: Adenosine treatment is safe and well tolerated and may be associated with fewer postoperative complications.

Adenosine↗

PubMed1998

Panel discussion. Data needs in cancer.

A prospective, comprehensive outcomes database was recently initiated by the National Comprehensive Cancer Network (NCCN) after a 2-year study to test data collection methods and systems. It started with data on 400 patients with newly diagnosed breast cancer at five NCCN sites, and over the next 3 years is projected to grow to include more than 12,000 patients with common cancers treated at all eligible NCCN sites. Among the goals of the database are: 1) to establish the capability to select, analyze, and report patterns of care and outcomes; 2) to allow NCCN members to assess their compliance with NCCN clinical practice guidelines and benchmark their performance against the rest of the NCCN; 3) to establish a true databased continuous quality improvement program; 4) to support clinical disease-oriented research and methodologic studies; and 5) to provide the NCCN with a vehicle for forging partnerships with others in the health-care field, such as the pharmaceutical industry, regulatory agencies, and accrediting bodies. Many of those potential partners were represented on this panel. Panelists discussed the data needs of their organizations, what they are doing to meet those needs, and how a comprehensive database will ultimately help improve patient care.

Aged↗