Duration and timing of sensitivity related to bleaching

PROBLEM

Reports of sensitivity vary greatly from one study to another, probably because studies are small. Generally, only the percentage of subjects is reported.

PURPOSE

This study reports sensitivity using a large database. We investigated the source, duration, and timing of sensitivity during 14 days of active bleaching.

MATERIALS AND METHODS

One hundred and seventy-two people recorded sensitivity from any of the five sources on a daily basis.

RESULTS

No one withdrew from the study because of sensitivity. Forty-seven percent of participants experienced sensitivity. Seventy-seven percent had sensitivity of 3 or fewer days. Temperature sensitivity tended to occur later in the 14-day bleaching cycle, and hot and cold sensitivity tended to occur together.

CONCLUSIONS

There was great variability in sensitivity levels from person to person. Temperature sensitivity tended to occur later in the active phase of bleaching, whereas irritation of the tongue tended to occur earlier.

CLINICAL SIGNIFICANCE

The results from a large group of people are more likely to include a wide cross-section of the population sampled. This data provides practitioners with a better estimate of what their patients are likely to experience. It is estimated that, during 2 weeks of active bleaching, 77% of people will experience 3 or fewer days of sensitivity. On average, sensitivity is short-lived, thus making it is easy to underestimate the importance of discussing sensitivity with patients considering bleaching. However, for some, the duration of sensitivity is much greater and has a very negative impact on satisfaction.

In Vivo Study of Two Carbamide Peroxide Gels with Different Desensitizing Agents

Under the conditions of this study, 15% carbamide peroxide with potassium nitrate and fluoride exhibited greater bleaching potential but exhibited no difference in sensitivity compared to 16% carbamide peroxide with amorphous calcium phosphate.

Sensitivity of Petrolatum and Aqueous Vehicles for Detecting Allergy to Imidazolidinylurea, Diazolidinylurea, and DMDM Hydantoin: A Retrospective Analysis from the North American Contact Dermatitis Group

OBJECTIVE

To determine whether petrolatum or aqueous vehicles are more sensitive for detecting allergy to imidazolidinylurea (IU), diazolidinylurea (DU), and dimethylol dimethyl hydantoin (DM). The relationship of these allergens to formaldehyde sensitivity was also explored.

METHODS

Retrospective analysis of patients patch-tested by the North American Contact Dermatitis Group. All patients were simultaneously tested to seven allergens (formaldehyde, IU in petrolatum [pet], IU aqueous [aq], DU pet, DU aq, DM pet, and DM aq). Data were analyzed in pairs with various "gold standard" definitions of "true allergy" and adjusting for correlated data.

RESULTS

Reaction to at least one of the seven allergens occurred in 2,398 patients. In all cases except one (which just approached statistical significance), the petrolatum-based allergen was statistically significantly more sensitive than the same allergen in an aqueous base. Most of the patients allergic to the three preservatives were also allergic to formaldehyde, but most formaldehyde-allergic patients were not allergic to the IU, DU, or DM.

CONCLUSION

Of these two vehicles, petrolatum is significantly more sensitive than an aqueous vehicle is for detecting allergy to IU, DU, and DM.

The microhardness of bleached dentine and its bond strength to a dentine bonding agent

The aim of this study was to measure the hardness of a bleached dentine surface and its bond strength to a dentine-bonding agent. Thirty teeth were randomly divided into a test and control group. The teeth were hemi-sectioned, the cut surfaces ground flat and the test surfaces bleached with a 10% aqueous solution of carbamide peroxide continuously for 4 days. Hardness was determined using a Vickers microhardness test. The bond between Coltene 'One Coat Bond' and bleached and unbleached dentine was evaluated by measuring shear bond strength using an Instron machine. The mean hardness of dentine before and after bleaching was 62.5 (10.2) and 53.6 (7.3) and this difference was statistically different (p<0.001). For the controls immersed in water the hardness was before 60.8 (standard deviation: 7.2) and after 59.6 (8.2) respectively. The mean shear bond strength for the unbleached was 5.5MPa (1.6) and for the bleached samples was 3.3MPa (1.8) and this difference was statistically significant (p<0.002). Under these study conditions the Vickers hardness and bond strength to dentine was reduced by bleaching.

Etiology and management of whitening-induced tooth hypersensitivity

Tooth hypersensitivity has long been, and continues to be, the most commonly reported adverse effect of vital tooth whitening with peroxide gels. The complex etiology of whitening-induced tooth hypersensitivity has been a major obstacle in developing a definitive strategy for its prevention. This article reviews the multiple etiologic factors implicated in whitening-induced tooth hypersensitivity and the evidence for efficacy of various strategies for its management.

Susceptibility of bleached enamel and root dentin to artificially formed caries-like lesions

PURPOSE

To evaluate in vitro the susceptibility of caries-like lesion formation on enamel and root dentin that had been bleached with carbamide peroxide agents.

METHODS

150 slabs of bovine enamel and root dentin were ground flat and polished. According to a randomized complete block design, the specimens were then allocated to be bleached with agents (Rembrandt) containing 12% [CP12], 16% [CP16], 22% [CP22] or 30% [CP30] of carbamide peroxide over 21 days. The control group remained unbleached. Afterwards, all specimens were randomly distributed between two subgroups (n= 15): one was subjected to alternating demineralizing and remineralizing solutions to induce caries-like lesions and the other was not. Enamel specimens were cycled four times in demineralizing (pH 5.0) and remineralizing solutions (pH 7.0), while root dentin specimens were cycled twice. Microhardness measurements were carried out at the post-bleaching and at the post-caries lesion formation phases.

RESULTS

In the post-bleaching condition, microhardness values for both enamel and root dentin were dependent on the bleaching agent used. At the post-caries formation stage, there was a significant interaction between the bleaching treatment and substrate condition (carious or noncarious) for enamel and root dentin. Regardless of the bleaching agent, carious enamel and root dentin presented significantly lower microhardness values as compared to the noncarious counterparts. For carious enamel, those specimens exposed to CP16 exhibited higher microhardness values than the subset group formed by CP22, CP30 and unbleached samples. Both subsets did not differ from CP12. For carious root dentin, no difference was observed among the microhardness values attained as a result of the different bleaching treatments.

Vital tooth whitening

Vital tooth whitening, when administered correctly, is by all accounts one of the safest, most conservative, least expensive, and most effective aesthetic procedures currently available to patients. This article traces the evolution of the technology, describes what is known about the mechanism of action and explores such issues as toxicology and side effects associated with tooth whitening. The article also describes the various tooth-whitening systems, which include dentist-supervised night-guard bleaching, in-office or power bleaching, and bleaching with over-the-counter bleaching products. Combination treatments and light-activated treatments are also discussed. Finally, the article summarizes the areas of research needed in this field.

Effect of Prolonged Direct and Indirect Peroxide Bleaching on Fracture Toughness of Human Dentin

STATEMENT OF THE PROBLEM

The effects of prolonged exposure to peroxide bleaching agents on dentin structural integrity are uncertain.

PURPOSE

To evaluate the effect of in vitro prolonged tooth bleaching on the fracture toughness (K(1C)) of human dentin.

MATERIALS AND METHODS

Dentin from recently extracted molar teeth was directly or indirectly treated to simulate a prolonged at-home (10% carbamide peroxide or 3% hydrogen peroxide, 6 hours/day, 5 days/week for 8 weeks) or in-office (30% hydrogen peroxide, 1 hour/week for 8 weeks) bleaching regimen (N=8/group). Placebo gel and distilled water acted as control materials. Compact tension test specimens (approximately 4.60 x 4.50 x 1.60 mm) were prepared from coronal dentin and tensile loading was applied at a rate of 10 mm/min 24 hours after the last bleaching session. Results were analyzed using analysis of variance and Tukey's test (p < 0.05). For direct bleach application, the treatment materials were applied onto dentin that was already prepared as compact tension specimens. For indirect bleach application, bleach was applied to the enamel of intact teeth prior to specimen preparation.

RESULTS

There was a significant decrease in dentin K(1C) after 8 weeks of direct bleach treatment (p < 0.05). There were no significant differences between the bleach and control groups after 8 weeks of indirect bleach treatment (p=0.19).

CONCLUSIONS

The in vitro fracture resistance of dentin was reduced after the prolonged use of bleach products that were applied directly to dentin.

CLINICAL SIGNIFICANCE

Caution should be considered when using bleach for prolonged treatment times in clinical cases where there is dentin exposure such as occlusal attrition or gingival recession.

Micromorphology and surface roughness of sound and demineralized enamel and dentin bleached with a 10% carbamide peroxide bleaching agent

PURPOSE

To evaluate the micromorphology and surface roughness of sound and demineralized enamel and dentin treated with a 10% carbamide peroxide bleaching agent in situ for 3 weeks.

METHODS

A 10% carbamide peroxide bleaching agent, Opalescence (OPA) was evaluated and a placebo agent (PLA) not containing carbamide peroxide, was used as a control group. Forty dental slabs [10 sound enamel slabs (SE), 10 demineralized enamel slabs (DE), 10 sound dentin slabs (SD) and 10 demineralized dentin slabs (DD)] were randomly fixed on the facial surface of the first maxillary molars and second maxillary premolars of 10 volunteers. Demineralized enamel and dentin fragments were obtained by a dynamic model using demineralizing and remineralizing solutions. The volunteers were divided into two groups that received the bleaching or the placebo agent in different sequences and periods in a double blind 2 x 2 cross-over study with a wash-out period of 2 weeks. Roughness was performed on the slab surfaces followed by scanning electron microscope (SEM) evaluations. The images were evaluated by three calibrated examiners in duplicate in two different periods at x1500 (SE and DE) and x2000 original magnification (SD and DD).

RESULTS

The Wilcoxon test showed significant differences in roughness for SE and DE treated with OPA or PLA, with rougher surfaces treated with OPA. No differences in roughness were observed for SD or DD treated with OPA or PLA. As the Kappa value for the inter-examiner agreement of SEM evaluations showed "moderate" reproducibility (0.41 < k< 0.60) in Period 1 and "substantial" (0.61 < k < 0.8) in Period 2, the latter was considered for the statistical analysis. The McNemar test showed no significant differences between SE, DE, SD or DD treated with OPA or PLA.

The Influence of Time Interval between Bleaching and Enamel Bonding

OBJECTIVES

The purpose of this study was to investigate the penetration of a conventional adhesive material into enamel bleached with 16% carbamide peroxide and 38% hydrogen peroxide using optical light microscopy.

METHODS

Extracted human teeth were randomly divided into eight experimental groups with six specimens each, according to the bleaching material and time interval after bleaching and before the bonding procedure. Groups were designated as follows: control group, restorations in unbleached teeth; restorations performed immediately after bleaching; restorations performed 7 days after bleaching; restorations performed 14 days after bleaching; and restorations performed 30 days after bleaching. The length of resin tags was measured with an Axiophot photomicroscope at 400x magnification for the calculation of the proportion of tags of study groups compared to the respective control groups. Analysis of variance was applied for comparison between groups; data were transformed into arcsine (p < 0.05).

RESULTS

The specimens of experimental groups, in which restorations were performed 7, 14, and 30 days after bleaching, showed better penetration of adhesive material into enamel than specimens restored immediately after bleaching. There was no statistically significant difference between the bleaching materials employed or in the interaction between bleaching agent and time interval.

CONCLUSIONS

This suggests that a time interval of at least 7 days should be allowed between enamel bleaching and placement of adhesive bonding agents for accomplishment of composite resin restorations.

CLINICAL SIGNIFICANCE

Establishment of adequate time after bleaching is fundamental to allow the normal penetration of a one-bottle conventional adhesive onto the enamel surface.

Effect of bleaching agents on calcium loss from the enamel surface

OBJECTIVES

To compare the Ca2+ loss of enamel treated with 38% hydrogen peroxide (HP), 35% HP with light, and 10% carbamide peroxide (CP).

METHOD AND MATERIALS

Ten extracted premolars were sectioned buccolingually and longitudinally so that 4 specimens were obtained from each tooth. The specimens were randomly assigned to 1 of 4 groups to receive the following bleaching agents: 38% HP, 35% HP with light, 10% CP, and no agent (control). The specimens were treated with an artificial caries solution (pH 4) for 16 days; the solution was replaced on days 4, 8, 12, and 16. Calcium concentration was determined by an atomic absorption spectrophotometer. Repeated measures ANOVA was performed on concentrations on days 4, 8, 12, and 16.

RESULTS

At the end of day 16, calcium ions released per square millimeter were calculated cumulatively as follows: 38% HP group: 27.52 +/- 5.22 microg/mL; 35% HP with light group: 25.15 +/- 4.99 microg/mL; 10% CP group: 19.53 +/- 4.03 microg/mL; control group: 18.35 +/- 4.00 microg/mL. The differences between the control group and the 35% HP with light group and between the control group and 38% HP group were statistically significant. Although demineralization differences were observed between the control group and the 10% CP group, this difference was not significant.

CONCLUSIONS

It can be concluded that 35% HP with light and 38% HP may cause significantly more loss of Ca2+ from the enamel surfaces than 10% CP. Also, 10% CP does not vary significantly from the control.

Micromorphology of enamel surface after vital tooth bleaching

The aim of the present study was to assess microroughness changes of enamel surfaces after bleaching procedures with 10% and 16% concentrations of carbamide peroxide by confocal laser scanning microscopy. Twenty caries-free incisors, extracted for periodontitis reasons, were sectioned into two halves of experimental and control specimens. The teeth were divided into two groups, and the experimental specimens were exposed to either 10% or 16% carbamide peroxide for 4 hours per 7 days. Measurements were made at three randomly selected 140 x 100 microm areas of 10 experimental and control specimens per group at the same crown level. Microroughness was measured in "total roughness" (Rt) and "average roughness" (Ra) descriptor values. The statistical analysis showed significantly higher microroughness according to Rt values and Ra values for both groups of carbamide peroxide exposed enamel surfaces.

Conservative aesthetic techniques for discoloured teeth: 1. The use of bleaching

There is an increasing move towards more minimally invasive techniques in restorative dentistry. This series of two articles discusses conservative techniques for the treatment of discoloured teeth. A step-wise approach to treatment is promoted to encourage the most conservative solution to achieve satisfactory aesthetics. The first of these two articles will describe the use of bleaching, whilst part two will go on to describe microabrasion and the use of direct composite resin.

CLINICAL RELEVANCE

Discoloured teeth are a common dental problem. Bleaching provides a simple conservative solution in many cases.

Efficacy and oral side effects of two highly concentrated tray-based bleaching systems

The aim of this study was to investigate the tooth-whitening efficacy and oral side effects of the two tray-based bleaching systems Visalys whitening (VW) and Opalescence PF (OP). A stratified, randomised distribution of the subjects (n = 60) to two treatment groups was performed according to baseline tooth brightness (L* values) as determined by colourimeter and to the criteria smoker/non-smoker. Tooth colour was evaluated by measuring L*a*b* values generated from standardised digital image analysis with Adobe Photoshop of the facial surfaces of the right central maxillary incisor. Tooth hypersensitivity, with intensity graded from 0 (no hypersensitivity) to 10 (high hypersensitivity), was assessed chair-side using an air syringe. After bleaching therapy, both treatment groups demonstrated significant improvements in tooth colour (p < or = 0.05). A shift towards less yellow (-Deltab*) and brighter (+DeltaL*) tooth colour was observed. Deltab* was significantly higher in the OP group in comparison to the VW group, DeltaL* showed no significant difference between the both treatment groups (p < or = 0.05). After bleaching, the intensity of tooth hypersensitivity was increased significantly compared to baseline in both groups (p < or = 0.05), with no significant difference between the both groups. Both highly concentrated bleaching systems are effective as tooth-whitening systems, with few reported side effects such as transient tooth hypersensitivity.

The effect of 2 different bleaching regimens on the surface roughness and hardness of tooth-colored restorative materials

OBJECTIVE

The purpose of this in vitro study was to evaluate the effects of 10% carbamide peroxide (Vivastyle/Vivadent) and 6.5% hydrogen peroxide strip bands (Crest Professional Whitestrips) on the surface roughness and hardness of the 3 different tooth-colored restoratives: an ormocer (Definite), a packable composite (Filtek P60), and a flowable composite (Filtek Flow).

METHOD AND MATERIALS

A total of 48 specimens (10 mm in diameter and 2 mm thick) of each material were fabricated against a mylar surface. After being polished with Sof-Lex discs, they were randomly divided into 3 groups of 16 and treated as follows: group I was stored in distilled water at 37 degrees C for 2 weeks (control), group II was treated with Vivastyle for 2 hours per day for 2 weeks, and group III was treated with Whitestrips for 30 minutes twice a day for 2 weeks. For groups II and III, the specimens were stored in distilled water at 37 degrees C during the hiatus period. At the end of the test period, the specimens were first subjected to surface roughness and then to microhardness tests. The data were analyzed by Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

Both bleaching regimens increased the surface roughness of the materials (P <.05), but Whitestrips significantly increased the roughness of materials more than did Vivastyle (P <.05). Both bleaching regimens decreased significantly the hardness of tested materials except Filtek P60 (P <.05).

CONCLUSION

Bleaching agents may affect the surface of existing restorations; therefore, they should not be used indiscriminately when tooth-colored restorations are present.

Neuropharmacological profile of FrPbAII, purified from the venom of the social spider Parawixia bistriata (Araneae, Araneidae), in Wistar rats

The aims of the present study were to investigate the anticonvulsant activity and behavioral toxicity of FrPbAII using freely moving Wistar rats. Moreover, the effectiveness of this compound against chemical convulsants was compared to that of the inhibitor of the GABAergic uptake, nipecotic acid. Our results show that FrPbAII was effective against seizures induced by the i.c.v. injection of pilocarpine (ED(50) = 0.05 microg/animal), picrotoxin (ED(50) = 0.02 microg/animal), kainic acid (ED(50) = 0.2 microg/animal) and the systemic administration of PTZ (ED(50) = 0.03 microg/animal). The anticonvulsant effect of FrPbAII differed from that of nipecotic acid in potency, as the doses needed to block the seizures were more than 10 folds lower. Toxicity assays revealed that in the rotarod, the toxic dose of the FrPbAII is 1.33 microg/animal, and the therapeutic indexes were calculated for each convulsant. Furthermore, the spontaneous locomotor activity of treated animals was not altered when compared to control animals but differed from the animals treated with nipecotic acid. Still, FrPbAII did not induce changes in any of the behavioral parameters analyzed. Finally, when tested for cognitive impairments in the Morris water maze, the i.c.v. injection of FrPbAII did not alter escape latencies of treated animals. These findings indicate that the novel GABA uptake inhibitor is a potent anticonvulsant with mild side-effects when administered to Wistar rats.

Effect of tooth-bleaching on the tensile strength and staining by caries detector solution on bovine enamel and dentin

PURPOSE

To evaluate the tensile strength and staining of enamel and dentin after extracoronal or intracoronal bleaching using conventional bleaching agents.

METHODS

Extracted bovine incisors were divided into eight groups of 10 specimens. Individual groups were treated by extracoronal bleaching (E) using in-office and home techniques with different concentrations of hydrogen peroxide (H2O2) and carbamide peroxide (CP); no bleaching (EN), 35% H2O2 and 10% CP (E35H-10C), 35% H2O2 and 20% CP (E35H-20C), 35% CP and 10% CP (E35C-10C), 35% CP and 20% CP (E35C-20C). Intracoronal "walking bleaching" (I) was performed after 24 hours of root canal treatment in the three remaining groups; no bleaching (IN); sodium perborate dissolved in 35% H2O2 (ISP-35H); and sodium perborate in distilled water (ISP-W). Mini dumbbell shapes of enamel and dentin with central cross-section diameters of 1.5 x 0.5 mm and 3 x 1 mm respectively were prepared for tensile testing using an Instron machine. Fracture surfaces were examined using SEM. Bleached enamel and dentin specimens were stained and evaluated using Caries Detector solution. Staining scores were analyzed using Kruskal-Wallis H and Mann-Whitney test (P < 0.05).

RESULTS

Tensile strengths (mean +/- SD) of enamel and dentin respectively for each group in MPa were: EN = 30.5 +/- 3.3 and 85.4 +/- 3.0, E35H-10C = 14.8 +/- 2.3 and 58.9 +/- 2.0, E35H-20C = 10.6 +/- 2.6 and 55.5 +/- 2.2, E35C-10C = 25.4 +/- 3.4 and 70.8 +/- 2.5, E35C-20C = 20.3 +/- 4.1 and 67.2 +/- 3.3, IN = 26.5 +/- 4.1 and 85.9 +/- 2.5, ISP-35H = 13.6 +/- 3.1 and 46.7 +/- 2.3, ISP-W = 21.7 +/- 3.3 and 68.3 +/- 4.4. ANOVA and Tukey HSD test found statistically significant differences among and between groups respectively (P < 0.05). No significant difference was found between non-bleached groups (IN and EN) of enamel and dentin. Mean tensile strengths of all bleached groups were significantly lower than those of non-bleached groups. Fracture surfaces demonstrated the different morphologies for bleached and non-bleached enamel and dentin.

The effect of 16 percent carbamide peroxide on enamel staining susceptibility

STATEMENT OF PROBLEM

Recently, vital bleaching by carbamide peroxide has become more popular; therefore, it is necessary to study the effect of this agent on enamel and dentin.

PURPOSE

The purpose of this study was to evaluate the effect of a 16 percent carbamide peroxide bleaching gel, Vivastyle, on enamel staining susceptibility.

MATERIALS AND METHODS

Thirty bovine specimens were selected and randomly divided into two groups of 15. The experimental group was subjected to Vivastyle gel and then was immersed in coffee for half an hour daily for three weeks. The control group was only immersed in coffee. The teeth were evaluated using a colorimeter to measure L*, a*, b* of each tooth. Value (black to white) is denoted as L*, wheres chroma (a* b*) is denoted as red (+a*), green (_a*), yellow (+b*), and blue (_b*). Total color differences between two colors (deltaE) were calculated using the following formula: deltaE = [(deltaL*)2 + (deltaa*)2+(deltab*)2]: deltaE1.Bleached, AE2: bleached and immersed in coffee, deltaE3: immersed in coffee.

RESULTS

Mean differences were: deltaE1 = 9.478, deltaE2 = 13.808 and deltaE3 = 7.230. Paired comparison by use of Duncan test showed there was a significant difference between deltaE1 and deltaE2 (P0.000); and t test showed there was no significant difference between deltaE3 and deltaE1. (P0.08 > 0.05), but deltaE3 showed a significant difference with deltaE2(P0.000).

CONCLUSION

After vital bleaching, the enamel staining susceptibility significantly increased.

Extended Bleaching of Tetracycline-Stained Teeth: A 5-Year Study

When using a tray delivery technique, tetracycline-stained teeth can be effectively lightened with the extended use of tooth whiteners. Cervical staining is the most difficult area to lighten.

Demineralization Effects of 2 Bleaching Procedures on Enamel Surfaces With and Without Post-treatment Fluoride Application

The results of this study suggest that post-treatment fluoride application prevents mineral loss in bleached enamel surfaces.

A phase I/randomized phase II, non-comparative, multicenter, open label trial of CP-547,632 in combination with paclitaxel and carboplatin or paclitaxel and carboplatin alone as first-line treatment for advanced non-small cell lung cancer (NSCLC)

PURPOSE

To evaluate the toxicity profile and pharmacological properties of oral CP-547,632 alone and in combination with paclitaxel and carboplatin administered every 3 weeks, and to assess efficacy as measured by the objective response and progressive disease rates of oral CP-547,632 administered in combination with paclitaxel and carboplatin.

PATIENTS AND METHODS

Patients with stage IIIB/IV or recurrent non-small cell lung cancer receiving first-line chemotherapy were treated with oral daily CP-547,632 in combination with paclitaxel 225 mg/m(2) and carboplatin AUC = 6 every 3 weeks. Pharmacokinetics parameters for CP-547,632 and paclitaxel were determined independently and during co-administration.

RESULTS

Seventy patients were enrolled and 68 patients were treated, 37 in phase 1 and 31 in phase 2 (14 with the combination and 17 with chemotherapy alone). Dose-limiting toxicity of CP-547,632 250 mg by mouth daily in combination with paclitaxel and carboplatin was grade 3 rash and grade 3 diarrhea despite medical intervention. CP-547,632 did not significantly affect the pharmacologic profiles of paclitaxel and carboplatin. No subject had CR. In phase I, seven subjects (22.6%) had a confirmed partial response. In phase II, four subjects (28.6%) receiving CP-547,632 plus chemotherapy had a confirmed partial response. In the phase II chemotherapy alone group, four subjects (25%) had a confirmed partial response.

CONCLUSION

The combination of CP-547,632 and paclitaxel and carboplatin was well-tolerated at doses up to 200 mg by mouth daily. Dose-limiting toxicity of CP-547,632 at 250 mg consisted of diarrhea and rash. CP-547,632 did not increase the objective response rate to chemotherapy alone in patients with advanced non-small cell lung cancer.

Pharmacodynamics and pharmacokinetics of the urotensin II receptor antagonist palosuran in macroalbuminuric, diabetic patients

OBJECTIVE

In patients with renal disease increased urotensin II plasma levels have been observed. We have investigated whether palosuran, a potent, selective, and competitive antagonist of the urotensin II receptor, has effects in patients who are prone to the development of renal disease.

METHODS

Macroalbuminuric, diabetic patients, categorized by renal function, were treated with oral doses of 125 mg palosuran twice daily for 13.5 days in addition to treatment with either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. The 24-hour urinary albumin excretion rate was determined twice at baseline and after 13.5 days of treatment. Plasma concentrations of palosuran were determined for 12 hours after the first and last drug intake. Renal hemodynamics was measured before and after 12.5 days of treatment. Tolerability and safety parameters were monitored.

RESULTS

An overall clinically significant reduction of 24.3% (geometric mean) (95% confidence interval, 4.1 to 45.0) in the 24-hour urinary albumin excretion rate was observed (P = .014). No effect was observed on renal hemodynamic parameters. Palosuran was rapidly absorbed with maximum plasma concentrations at 1 hour after drug administration. The accumulation factor was 1.7 (geometric mean) (95% confidence interval, 1.3 to 2.1). Palosuran was well tolerated.

CONCLUSIONS

The good tolerability profile and the decrease in the 24-hour urinary albumin excretion rate may benefit diabetic patients with renal failure with regard to their disease progression. Larger placebo-controlled trials in this patient population are needed to investigate whether urotensin II receptor antagonists, given as monotherapy or combination therapy, may improve the current treatment of diabetic nephropathy.

An increase of anticardiolipin antibody in association with stroke and chronic chemical exposure

A chemical worker working with urea-formaldehyde resin hazard for 20 years suffered cerebral ischemia in association with an increase of blood beta2-glycoprotein I-dependent anticardiolipin antibody (aCL)-IgG and IgM isotype, and a prolongation of activated partial thromboplastin time (aPTT). Major histocompatibility complex antigen showed DR4 positivity. On follow-up for over 6 years, aCL-IgG and aPTT decreased to reference range but aCL-IgM was still abnormally high despite a cessation of exposure. This patient highlights the induction of antibody-mediated thrombosis in chronic chemical exposure, especially in an individual with subclinical autoimmune disorder. The role of environment for coagulopathic vascular thrombosis is warranted for investigation.

Randomized clinical trial on the efficacy of a new bleaching lacquer for self-application

BACKGROUND

This study evaluated the clinical efficacy and duration of effectiveness of a new bleaching lacquer for self-application without the use of mouth guards. It compared two different application times.

METHODS

Forty-six adult subjects who requested bleaching treatment were selected to participate in this randomized, single-blind (examiner-blinded), single center, two-group trial. The subjects were randomly divided into two groups (n=23 each), each being instructed to bleach (8% carbamide peroxide) their six maxillary anterior teeth for two weeks. Daily contact time in Group 1 was 20 minutes once a day and, in Group 2, the time was 20 minutes twice a day. Efficacy was measured subjectively using the Chromascop Complete shade scores obtained at baseline and after one, two and three weeks, as well as after one, three, six and nine months.

RESULTS

After two weeks of treatment, the teeth in the Group 1 subjects exhibited a 2.4 +/- 0.2 mean shade scores improvement compared to baseline (p < 0.001; t-test for paired samples), and the subjects' teeth in Group 2 exhibited a 3.5 +/- 0.1 mean shade scores improvement (p < 0.001). However, the difference between both groups was not statistically significant (p > 0.05). The observed effects were stable for six months.

CONCLUSIONS

It can be concluded that the new bleaching lacquer is efficacious; however, a double application does not seem to be obligatory.