Clinical Study of Tooth Shade Lightening from Dentist-Supervised, Patient-Applied Treatment with Two 10% Carbamide Peroxide Gels

Abstract: Purpose : Prescribed, patient-applied tooth lightening agents, or nightguard vital bleaching, typically utilizes a 10% carbamide peroxide agent applied during nocturnal hours. The purpose of this randomized double-blind study was to compare the amount of tooth color change in two groups of subjects using dentist-supervised, patient-applied 10% carbamide peroxide gel.
Materials and Methods : One group used Opalescence® (Ultradent Products Inc., South Jordan, Utah) and the other Nite White Excel® (Discus Dental, Inc., Los Angeles, California). Evaluation of tooth color for the six maxillary anterior teeth was done using a Vita shade guide at baseline, 1, 2, and 4 weeks. Subjects were instructed to apply the gel nocturnally using a custom-made soft tray 8 hours per day for 2 weeks. The 16 tabs of the shade guide were ranked according to value from darkest to lightest. The number (1–16) that correlated to the shade tab selected as the match for each tooth was the outcome variable. A Kruskal-Wallis one way analysis of variance on ranks was used.
Results : The test revealed no statistically significant difference between Opalescence® and NiteWhite® Excel for lightening the teeth ( p = .807). The color change was still significant after 2 weeks without further bleaching activity. The baseline evaluation of the maxillary incisors and canines for all subjects, regardless of group, demonstrated a significant shade difference, with the canines being darker. This difference was not seen after 2 weeks of active bleaching or at the 4-week evaluation.     

The nature of the late positive complex within the olfactory event-related potential (OERP)

The olfactory event-related potential (OERP) has been described as being dependent on exogenous stimulus features, but no effect has been made to examine possible endogenous determinants. We wanted to separate exogenous and endogenous components of the OERP by using an olfactory oddball paradigm. A high concentration of citral was used as the target stimulus, and a low concentration was used as the standard stimulus. Odors were presented within a constantly flowing air stream. We found that the early components of the OERP (N1, P2) are modulated by the stimulus concentration, whereas the late positive components (P3-1, P3-2) vary depending on the subjective stimulus significance and stimulus probability. It is concluded that the positive component of the OERP, which has been formerly explained by chemical and physical stimulus features, is actually determined by endogenous processes.     

Late Hyponatremia in Very-Low-Birth-Weight Infants: Incidence and Associated Risk Factors

Objective To determine the incidence of late hyponatremia in very-low-birth-weight infants and to identify associated risk factors. Low serum sodium concentration in otherwise healthy premature infants beyond 2 weeks of life is referred to as late hyponatremia.Design Retrospective cohort review.Setting/subjects The intensive care nursery at St Luke's Hospital Perinatal Center, Kansas City, Mo. Criteria for subject selection were birth weight of 1,500 g or less; survival for more than 21 days; development of late hyponatremia or hospitalization for 42 days or more; and measurement of serum sodium concentration at least once between the 14th and 56th day of life. Of 515 infants admitted to the nursery for the 1992 calendar year, 124 had a birth weight of 1,500 g or less and survived for more than 21 days; however, 16 of these infants were discharged at 42 days of life or less, 11 did not have a serum sodium concentration measurement after the second week of life, and 1 did not have complete medical records. Thus, the final sample was 96 subjects.Statistical analyses Percentages to determine incidence of late hyponatremia; t test or χ² test to determine differences between infants with and without late hyponatremia; multiple logistic regression to determine the strongest indicators of late hyponatremia.Results Incidence of late hyponatremia was 62.5%. Significant risk factors for late hyponatremia were birth weight of 1,000 g or less (P<.001), feedings of fortified human milk (P<.013), and occurrence of an intraventricular hemorrhage (P<.036). Fortified human milk feeding was a significant risk factor for late hyponatremia in both weight groups (ie, birth weight greater than or less than 1,000 g).Conclusion Despite standard fortification, human milk may contain an insufficient quantity of sodium to met the needs of very-low-birth-weight infants. J Am Diet Assoc. 1996; 96:880-884.     

'Enabling' of male problem drinkers in work groups

Theoretical understanding of the effects of groups on the development and the maintenance of adult problem drinking is sparse. Sociological theories predict that adult problem drinkers find support for their behavior among those with similar drinking patterns. By contrast, a widely diffused clinical conceptualization posits that ‘significant others’ who are not problem drinkers facilitate the maintenance of problem drinking. Several previous lines of research lead to the hypothesis that observed delays in identification and referral of problem drinkers in the workplace may be due to supportive relationships between problem drinkers and their co-workers and supervisors. Data from the 1973–77 Quality of Employment Panel Survey are utilized to provide a longitudinal test of this hypothesis among employed men. Results support the existence of enabling in the workplace. Data comparing ‘enabled’ and ‘non-enabled’ problem drinking workers fail to support four possible explanations of enabling.     

Diagnosis of mitral valve myxoma by transesophageal echocardiography

Mitral valve myxomas are rare. We report a patient with a mitralmyxoma arising from the posterior mitral leaflet in whom transthoracicechocardiography revealed equivocal findings. However, transoesophagealechocardiography provided accurate relevant anatomical informationincluding the size, morphological characteristics, and tumourattachment point.