Clinical Evaluation of Different Delivery Methods of At-Home Bleaching Gels Composed of 10% Hydrogen Peroxide

OBJECTIVES:

This study aimed to compare the tooth sensitivity, gingival irritation, and bleaching efficacy of at-home whitening performed with 10% hydrogen peroxide (HP) using a conventional tray-delivered system or two different bleaching systems (strips or prefilled disposable trays).

METHODS AND MATERIALS:

Sixty patients, with maxillary incisors darker than A2 were selected for this single-blind, parallel randomized clinical trial. Teeth were bleached during 14 days with a 30-minute gel contact with teeth per day. The 10% HP was delivered in a bleaching tray (White Class, FGM) in strips (White Strips, Oral-B) or prefilled disposable trays (Opalescence Go, Ultradent). The color changes were evaluated by subjective (Vita Classical and Vita Bleachedguide) and objective (Easyshade Spectrophotometer) methods at baseline and 30 days after the second bleaching session. Tooth sensitivity was recorded during 14 days with a five-point numeric rating scale (NRS) and 0-10 visual analog scale (VAS). The risk of gingival irritation was also recorded during 14 days on a dichotomous scale. All data were submitted to appropriate statistical analysis (α=0.05).

RESULTS:

No significant difference was observed in the risks of tooth sensitivity among groups ( p>0.09). However, the conventional bleaching tray produced a higher intensity of tooth sensitivity when compared with the strips and prefilled disposable tray systems ( p<0.04). Regarding gingival irritation, the prefilled disposable tray system showed a lower risk of gingival irritation when compared with the conventional bleaching tray ( p=0.003). Significant whitening was observed in all groups after 30 days of clinical evaluation with no significant difference between them ( p>0.06).

CONCLUSIONS:

All 10% HP bleaching systems showed similar whitening after a 14-day use. However, the strips and prefilled disposable trays produced lower intensity of tooth sensitivity than the conventional bleaching tray system. The prefilled disposable tray produced lower risk of gingival irritation when compared to the conventional bleaching tray.

Methods for evaluation of masticatory efficiency in conventional complete denture wearers: a systematized review

The objective of this study was to present a systematized review of different methods used to evaluate the masticatory efficiency in conventional complete denture wearers. A survey was conducted in the databases PubMed, Scopus, and Cochrane, seeking scientific articles according to the previously selected terms: "Masticatory performance", "Masticatory efficiency" and "Chewing ability complete denture". Moreover, complementary studies have been carried out with library manual search/databases, which included studies related to different ways to assess masticatory efficiency, specifically as it related to conventional complete denture wearers. Forty three papers were selected to be used in the present review. Despite the wide variety of methodologies in the literature, the sieves method is currently considered the gold standard method to evaluation of conventional complete denture wearers masticatory efficiency, since it is the simplest, does not depend on specific devices (beyond the set of sieves), allows for a rational assessment, and it has been widely reproduced in various types of oral rehabilitation. More, the almond, as natural test food, and the optocal (made from the molding material Optosil), as artificial test food, are the most constantly employed test foods to evaluate masticatory efficiency.

β3-Adrenoceptor agonist AJ-9677 reduces body fat in obese beagles

A selective beta3-adrenoceptor agonist, AJ-9677, was reported to ameliorate obesity and insulin resistance in KK-Ay mice. We examined the acute and chronic effects of AJ-9677 on obese dogs. Oral administration of AJ-9677 (0.01 or 0.1 mg/kg) to overnight fasted obese beagles produced a dose-dependent rise in the plasma levels of non-esterified fatty acids and insulin in 1h, followed by a gradual drop of the plasma glucose level. It produced no apparent abnormal behaviors, but easily detectable cutaneous flushing. Daily treatment of AJ-9677 at a lower dose (0.01 mg/kg) for three weeks produced no notable change in body weight, but at a higher dose (0.1 mg/kg) it reduced the body weight compared to a placebo treatment after seven weeks. Computed tomographic examinations revealed a remarkable reduction of body fat after the AJ treatment, being consistent with the histological observations that the adipose tissue of AJ-9677-treated dogs consisted of smaller and some multilocular adipocytes. The plasma levels of leptin and adiponectin were decreased and increased, respectively, after the AJ treatment, reflecting the reduction of adiposity. It was concluded that AJ-9677 is useful for the treatment of obesity in the dog.

Three different types of congenital lacrimal sac fistulas

Three different symptoms in 4 patients with congenital lacrimal sac fistulas are presented. The first symptom was epiphora since birth, the second symptom was infection of the lower eyelid, and the third symptom was tearing from the eye in a 76-year-old patient. This patient had nasolacrimal obstruction at the canal level and no symptoms of congenital lacrimal sac fistula. She had undergone excision, including dacryocystorhinostomy. Three of the 4 patients underwent excision of the fistulous tract. The fistula originated from the lacrimal sac in all patients. Symptomatic congenital lacrimal sac fistulas can be treated successfully with excision alone or with excision and dacryocystorhinostomy in cases of nasolacrimal obstruction.

Synthesis of a molt-inhibiting hormone of the American crayfish, Procambarus clarkii, and determination of the location of its disulfide linkages

A molt-inhibiting hormone (Prc-MIH) of the American crayfish, Procambarus clarkii, a member of the type II CHH family, was chemically synthesized and the location of its three disulfide linkages was determined. Prc-MIH consists of 75 amino acid residues and was synthesized by a thioester method. Two peptide segments, Boc-[Cys(Acm)(7,24,27), Lys(Boc)(19)]-Prc-MIH(1-39)-SCH(2)CH(2)CO-Nle-NH(2) and H-[Cys(Acm)(40,44,53), Lys(Boc)(42,51,67)]-Prc-MIH(40-75)-NH(2), were prepared using peptides obtained via the Boc solid-phase method. Condensation of the building blocks in the presence of silver chloride, 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine, and N, N-diisopropylethylamine, followed by removal of the protecting groups, gave the reduced form of Prc-MIH(1-75)-NH(2). This product was converted to the native form of Prc-MIH (synthetic Prc-MIH) in a buffer which contained cysteine and cystine. The synthetic Prc-MIH showed the same behavior by RP-HPLC and biological activity assays as the natural Prc-MIH. The disulfide bond between Cys7 and Cys44 was determined by isolation of a fragment from an enzymatic digest of the synthetic Prc-MIH by RP-HPLC, followed by mass analysis. The disulfide bonds between Cys24 and Cys40 and between Cys27 and Cys53 were determined by comparing the elution position of an enzymatic digest of the synthetic Prc-MIH with authentic chemically synthesized samples, which contained three types of possible disulfide linkages.

[Effect of thiabendazole (TBZ) on glutathione (GSH) and GSH related enzymes in mice liver]

The present study examines the effects of thiabendazole (TBZ), its metabolites, 5-hydroxythiabendazole (5-OH TBZ) and 2-acetylbenzimidazole (ABI), and structural related compounds, thiazoles and thioamides on glutathione (GSH) concentration and GSH-related enzymes in the livers of ICR 11 week-old female mice. GSH concentration in liver and kidney of mice given orally TBZ 0.65 mol/kg (TBZ group) increased significantly compared with control mice from 24 h to 48 h after administration of TBZ. Even in mice to which TBZ at 0.175 mol/kg was administered in combination with L-buthionine sulfoximine (BSO) 4 mmol/kg (i.p.) (BSO-TBZ group), kidney GSH showed significant increase compared with BSO-control mice 48 h after the administration of TBZ. gamma-Glutamylcysteine synthetase (gamma-GCS) activity in the livers of the TBZ group markedly increased at 48 h and that of BSO-TBZ group increased from 24 h to 48 h. gamma-GCS in mice liver is thus enhanced by TBZ regardless of BSO administration. Hepatic glutathione peroxidase activity of the TBZ group did not change in response to cumene hydroperoxide assubstrate. That of BSO-treated mice decreased by TBZ-coadministration and significant differences was noted between BSO-control and BSO-TBZ group from 1 h to 48 h later. Hepatic glutathione S-transferase (GST) activity toward 1,2-dichloro-4-nitrobenzene (DCNB) was significantly elevated 24 h after administrations of TBZ in TBZ and BSO-TBZ groups. GST activity toward 1,2-epoxy-3-(p-nitrophenoxy) propane of TBZ group increased from 0.5 h to 24 h. Hepatic GST activity toward DCNB and 1-chloro-2,4-dinitrobenzene did not change by administration of 0.65 mol/kg 5-OH TBZ or ABI but increased by administrations of 0.33 mol/kg of thiazole, 4-methylthiazole, 4,5-dimethylthiazole or 2,4-dimethylthiazole. Increase in GSH concentration and GST activity in mice liver by TBZ administration may be considered to provide protection from TBZ or its active metabolites.

Reduction of operating time and blood transfusion for craniosynostosis by simulated surgery using three-dimensional solid models

Preoperative planning of craniofacial synostosis can be achieved through the use of two- or three-dimensional (3D) computed tomography (CT) images and by 3D solid models. The advantage of using 3D models was evaluated by calculating the amount of blood transfused and the operating time for 36 craniosynostosis procedures, 21 planned with 3D models and 15 with CT images performed in the past 7 years. The use of 3D models reduced both blood loss and operating time for fronto-orbital advancement with reshaping, LeFort III advancement, and LeFort IV minus Glabellar advancement; blood loss for fronto-orbital advancement without reshaping; and operating time for total cranial reshaping.

Osteoblastoma of the nasal cavity invading the anterior skull base in a young child. Case report

The benign osteoblastoma is rarely seen as a tumor of the facial bone in infancy or early childhood. Only five cases with nasal involvement have been reported in the literature. The authors present a case of osteoblastoma of the nasal cavity, the nasal bone, the ethmoid sinus, and the anterior cranial base. This 3-year-old girl presented with a tumor surrounding the left medial canthus. Imaging studies, including x-ray films, computerized tomography scans, magnetic resonance images, a (99m)Tc-scintigram, and angiograms, confirmed the location of the tumor. A biopsy specimen of tumor was obtained intranasally and the pathological diagnosis was an osteoblastic tumor suggestive of osteoblastoma. Although the tumor margin was well defined on the radiological images, it was difficult to determine the exact margin during the operation. Therefore, it is important to show how to excise the tumor completely under direct view. With the use of a "dismasking flap," it was possible to resect the benign osteoblastoma completely from the nasal cavity, even though it extended into the orbit, the maxilla, and the anterior cranial base.

[Influence of preload alteration on the transmitral flow velocity in patients with old myocardial infarction: effects of nitroglycerin and lower body negative pressure]

We studied the influence of preload alteration on the pattern of transmitral flow as obtained by pulsed Doppler echocardiography. In protocol I, 14 patients with old myocardial infarction (OMI) were observed by simultaneous measurements of transmitral flow by PDE and left ventricular end-diastolic dimension (LVDd) using M-mode echocardiography during the control period and after sublingual nitroglycerin. In protocol II, eight patients with OMI were similarly observed during stepwise lower body negative pressure (LBNP: 0, -10 and -20 mmHg). The rapid filling phase was categorized in two subphases at peak R as the first half and second half phases. The integrals of each half phase and the atrial systolic phases (IR1, IR2 and IA) were measured by planimetry. After the administration of nitroglycerin, LVDd decreased significantly; whereas the mean arterial pressure decreased and heart rate increased significantly. The peak R and IR1 decreased significantly, but the peak A, IR2 and IA remained unchanged. During LBNP, LVDd decreased stepwise; whereas there was no change in the mean arterial pressure or heart rate. The changes in the peak R and IR1 paralleled the preload reduction during LBNP. The peak A, IR2, and IA remained unchanged. In conclusion, the first and second half volumes during the LV rapid filling phase can be influenced by various factors. The patterns of the transmitral flow velocity, the maximal velocity and first half volume in the LV rapid filling phase may be influenced by preload alteration.

Pulsed Doppler echocardiographic assessment of transmitral flow in pacing-induced angina pectoris

We analyzed transmitral flow using pulsed Doppler echocardiography during anginal attack provoked by atrial pacing in 11 patients with coronary artery disease (CAD). Left ventricular (LV) filling period was divided into 4 time intervals (Tr1: the time interval to peak velocity of rapid filling (peak R), Tr2: the time interval from peak R to the end of rapid filling, Ts: the time interval of slow filling, Ta: the time interval of atrial contraction). The velocity in each interval was integrated by planimeter as IR1, IR2, IS or IA which indicates relative filling volume in each interval. During angina, IR1 was unchanged due to prolongation of Tr1 (82 +/- 21 to 102 +/- 23 msec, p less than 0.02), despite a decrease in peak R (54 +/- 11 to 43 +/- 11 cm/sec, p less than 0.005), while IR2 decreased (5.8 +/- 1.9 to 4.3 +/- 1.4 cm, p less than 0.005) and IA increased (6.7 +/- 1.4 to 7.3 +/- 1.3 cm, p less than 0.005). In conclusion, these results suggested that in acute myocardial ischemia in CAD a decrease in transmitral flow from the time of peak R to the end of rapid filling (IR2) reflected the impairment of the LV rapid filling, which was incompletely compensated by an increase in atrial contraction.

Placental transfer of ochratoxin A and its cytotoxic effect on the mouse embryonic brain

Pregnant ICR mice were given a single ip injection of 5 mg ochratoxin A/kg on day 11 or 13 of pregnancy. Concentrations of ochratoxin A in the maternal serum and tissues reached maximum levels within 2 hr of the injection and then decreased rapidly. The half-life of the toxin in serum was 28.7 hr on day 11 and 23.6 hr on day 13. On the other hand, the concentrations of ochratoxin A in the embryos were very low 2 hr after injection and then gradually increased up to 48 and 30 hr after injection on day 11 and 13, respectively. Pharmacokinetically, the embryo was found to be a 'deep' compartment. In mice treated with ochratoxin A on day 10 of pregnancy, the incidence of pyknotic cells in the telencephalon of the embryos began to increase 12 hr after injection to a peak between 36 and 48 hr, coinciding with the time of peak concentration of the toxin in the embryo.

A comparison of two exponential models of the time constant during left ventricular isovolumic pressure decay in coronary artery disease

To make a comparison of two exponential models of the time constant (Tw: Weiss's method, Tc: exponential analysis with a variable asymptote) during left ventricular (LV) isovolumic relaxation, we assessed LV pressure decay in 104 patients with coronary artery disease (CADpts) and 21 normal subjects at rest and after pacing, and investigated the hemodynamic determinants of these two models using forward-backward stepwise multiple regression analysis. At rest, Tw was prolonged as the left ventricular minimal pressure (LVPmin), the left ventricular end-diastolic pressure (LVEDP) and the end-systolic volume (ESV) increased (multiple regression coefficient: R = 0.87), whereas Tc was prolonged as ESV and regional wall motion abnormality (RWMA) increased (R = 0.72). Pacing-induced changes in Tw were augmented as LVPmin and RWMA increased (R = 0.75), whereas changes in Tc were augmented as RWMA increased (R = 0.63). Thus, the changes in Tw may be due to an increase in LVPmin rather than to any direct effect of ischemia on the relaxation rate. The relaxation rate can be evaluated more reliably by Tc than by Tw, irrespective of associated pressure changes during ischemia in CADpts.

Effects of left ventricular asynchrony on time constant and extrapolated pressure of left ventricular pressure decay in coronary artery disease

To elucidate the effects of ventricular asynchrony with or without myocardial ischemia on the time constant of left ventricular pressure decay and asymptote, that is, the level to which pressure would decrease if isovolumic pressure decrease continued infinitely, left ventriculography and pressure measurements were investigated in 14 normal subjects and 25 patients with coronary artery disease. Ventricular asynchrony was quantitated by the segmental area-time curve. This study consisted of two parts. 1) After a right atrial pacing stress test, the time constant and asymptote remained unchanged in eight normal subjects. In 18 patients with coronary artery disease and pacing-induced angina, asynchrony increased, the time constant was prolonged (64 +/- 13 to 94 +/- 17 ms, p less than 0.01) and the asymptote decreased (-22 +/- 10 to -46 +/- 20 mm Hg, p less than 0.01) after the pacing. 2) During right ventricular pacing at 80, 100 and 120 beats/min in the patients, asynchrony increased and the time constant was prolonged (55 +/- 7 versus 70 +/- 10, 47 +/- 11 versus 66 +/- 19, 36 +/- 7 versus 53 +/- 13 ms, respectively, p less than 0.01 versus right atrial pacing), whereas the asymptote was unchanged in six normal subjects compared with the value during right atrial pacing at each pacing rate. In seven patients with coronary artery disease, right ventricular pacing at 80, 100 and 120 beats/min also produced an increase in the time constant, while the asymptote was unchanged. Thus, prolongation of the time constant of left ventricular pressure decay may result from ventricular asynchrony even in the absence of myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of diltiazem and nitroglycerin on left ventricular diastolic properties in patients with coronary artery disease

To determine the effects of diltiazem (DTZ) and nitroglycerin (NTG) on left ventricular (LV) diastolic relaxation and filling in patients with cornary artery disease (CADpts), LV graphy and time constant (Tc) of LV isovolumic pressure decay were studied before and 5 min after intravenous DTZ (10 mg) in 16 CADpts and sublingual NTG (0.3 mg) in 11 CADpts. Diastolic regional ventricular filling dynamics were quantitated by segmental area-time curves during early-, mid- and late-filling periods. After NTG, LV systolic pressure (LVSP), end-diastolic pressure (EDP) and end-diastolic volume (EDV) decreased. Early-filling rate (EFR) decreased (165 +/- 82 to 122 +/- 61 ml/sec/m2) due to a decrease in the regional early-filling rate in the normokinetic area and late-filling rate (LFR) increased (95 +/- 38 to 145 +/- 45 ml/sec/m2), while LV peak positive dp/dt, peak LVSP/end-systolic volume (ESV) ratio, Tc and mid-filling rate (MFR) were unchanged. After DTZ, LVSP decreased and EDV increased. EFR increased. EFR increased (127 +/- 54 to 166 +/- 60 ml/sec/m2) due to an enhanced regional early-filling rate in the mildly hypokinetic area, while EDP, LV peak positive dp/dt, peak LVSP/ESV ratio, Tc, MFR and LFR were unchanged. From these results, it was postulated that NTG caused a decrease in LV early filling and an increase in LV late filling, probably due to LV preload reduction. In contrast, DTZ caused significant improvement of LV early filling particularly in the mild hypokinetic area. Thus, DTZ but not NTG was able to relieve local myocardial dysfunction secondary to a stenosed coronary artery during the filling period, resulting in clinical improvement in CADpts.

Assessment of left ventricular function in ischemic heart disease. The relation between pressure decay during the isovolumic relaxation phase and regional wall motion abnormality

We examine whether regional wall motion abnormality (RWMA) could contribute to the slowed relaxation rate of the left ventricle (LV) in patients with coronary artery disease (CADpts). Simultaneous observations were made on the time constant (Tc) of the isovolumic pressure decay and left ventriculography at the control period and after right atrial pacing. Subsequently, the subjects investigated were divided into 3 groups, i.e. normal subjects (Group I, n = 8), CADpts with normal wall motion during the control period (Group II, n = 21), and CADpts with RWMA during the control period (Group III, n = 28). The latter two groups were further divided into two subgroups according to the presence (Group IIa and IIIa) or absence (Group IIb and IIIb) of pacing-induced RWMA. We measured Tc by a method of exponential analysis that could estimate the asymptote. During the control period, Tc was significantly prolonged in Group III (82 +/- 26 msec) than that in Group I (60 +/- 6 msec) and Group II (63 +/- 12 msec). Tc was prolonged in proportion to the extent of RWMA during the control period. Immediately after right atrial pacing, Tc was markedly prolonged in Group IIa (from 61 +/- 12 to 90 +/- 20 msec, p less than 0.001) and in Group IIIa (from 73 +/- 26 to 95 +/- 34 msec, p less than 0.001). The post-pacing prolongation of Tc was closely correlated with the extent of post-pacing RWMA. From these results, it is postulated that RWMA may play an important role as a causes of the altered LV relaxation in CADpts.

Unresponsiveness of GH and cortisol to insulin-hypoglycemia in a patient with sub-total pancreatectomy

Responses of plasma growth hormone (GH) and cortisol to insulin-induced hypoglycemia were repeatedly examined during a therapy of diabetes mellitus in a sub-totally pancreatectomized patient. During a mild control period of diabetes mellitus without any hypoglycemic attacks, insulin-induced hypoglycemia evoked a remarkable increase in plasma GH as well as cortisol while neither GH nor cortisol responded to insulin hypoglycemia during the strict control period with frequent episodes of hypoglycemia. On the other hand, plasma GH and cortisol responses to all other endocrinological stimuli were normal. The mechanism of such impaired hormone secretion during the strict control period of diabetes mellitus in this patient remains unclear.

A case of brain atrophy after fulminant hepatic failure

We report a 26-year-old woman who survived fulminant hepatic failure but later developed permanent brain atrophy. After her recovery from fulminant hepatitis, her personality changed and mental abnormalities became obvious. Four years after the onset of fulminant hepatitis an epileptic attack occurred. At that time CT-scanning revealed generalized brain atrophy.