Successful pregnancy in an adolescent woman with a communicating double uterine anomaly.

BACKGROUND: Women with communicating double uterine anomalies are at increased risk for obstetric complications, including early pregnancy loss, preterm delivery, and breech presentation. We present the pregnancy of a woman with a previously diagnosed communicating double uterine anomaly. CASE: An 18-yr-old white female with a previous diagnosis at age 11 of a communicating double uterus, double cervix, and obstructed left hemivagina was followed during the course of her pregnancy. She experienced no complications until 36 6/7 weeks, when she was found to have signs and symptoms of mild preeclampsia. The fetus was in a breech presentation and a cesarean section was performed. Two hemiuteri were identified intraoperatively. The communication was not visualized. A viable male infant was delivered without complications. CONCLUSION: This patient represents only the sixth report of successful pregnancy in a woman with a Toaff type 5A communicating uterine anomaly.

Sexual abuse knowledge base among residents in family practice, obstetrics/gynecology, and pediatrics.

STUDY OBJECTIVE: To investigate resident physician knowledge about sexual abuse prevalence and understanding about potential perpetrators. DESIGN: Questionnaires were mailed to program directors in family practice, obstetrics and gynecology, and pediatric residency programs. PARTICIPANTS: The questionnaires were distributed to senior residents in their final months prior to graduation. INTERVENTIONS: Residents were asked to fill out the questionnaire anonymously and return it to our institution in the prepaid envelope provided. MAIN OUTCOME MEASURES: Demographic characteristics and knowledge of sexual abuse prevalence and perpetrator characteristics were assessed. Chi-square contingency table analysis was used to compare responses of the three specialties. RESULTS: The overwhelming majority (98.8%) of residents correctly identified a family member as the individual most likely to sexually abuse a child. Approximately half of the residents knew the correct prevalence of sexual abuse among females and among males. There was a weak understanding of the potential youthfulness of juvenile offenders. CONCLUSION: We believe that resident understanding of sexual abuse prevalence and about the youthfulness of juvenile offenders can be improved in all three specialties.

Comparisons of two approaches for removing excess adhesive during the bonding procedure.

The purpose of this study was to compare the effects on shear bond strength of removing excess adhesive from around the bracket base at 2 time periods: (1) immediately after placing the bracket on the tooth, and (2) after subjecting the adhesive to 5 seconds of light curing to initially secure the bracket in its proper position. The debonding forces were evaluated at 2 times; within half an hour after bonding and after storing for 24 hours in water at 37 degrees qC. These comparisons will help determine the most advantageous time for the clinician to remove excess adhesive from around the brackets during the bonding process. The teeth were randomly divided into 4 groups according to: (a) the time of removal of the excess adhesive from around the bracket base namely; immediately after placing the bracket or after 5 seconds of light cure and (b) the time of debonding the brackets, namely within half an hour or after 24 hours. Shear bond strength was measured using a Zwick test machine and calculated in Megapascals. The results of the analysis of variance (F = 35.05) comparing the 4 experimental groups indicated the presence of significant differences between all 4 groups (P = .0001). In general, the shear bond strengths were significantly larger for the 2 groups debonded after 24 hours, whether they were light cured for a total of 40 seconds (X = 8.8 +/- 3.6 MPa) or 45 seconds (X = 6.9 +/- 3.4 MPa). On the other hand, the shear bond strengths was significantly lower in the 2 groups debonded within half an hour from their initial bonding, whether light cured for 40 seconds (X = 0.4 +/- 1.0 MPa) or 45 seconds (X = 3.4 +/- 2.7 MPa). In conclusion, the additional 5 seconds of light cure significantly increased the initial shear bond strength. On the other hand, removing excess adhesive after 5 seconds of light cure significantly decreased the shear bond strength at 24 hours.

Effect of light-cure time on the initial shear bond strength of a glass-ionomer adhesive.

With the introduction of photosensitive (light-cured) restorative materials in dentistry, various methods were suggested to enhance the polymerization of these materials including layering and the use of more powerful light-curing devices. The purpose of this study was to determine the effects of increasing the light-cure time on the initial shear bond strength (in the first half hour) of a resin-modified glass-ionomer adhesive. Eighty-six teeth were divided into 4 groups according to either; (1) the adhesive system used, namely resin, reinforced glass ionomer, or composite, and (2) the light-cure time for the glass ionomer adhesive, namely 40, 45, and 50 seconds. The bonding approach followed the manufacturer's instructions unless otherwise specified. The results of the analysis of variance comparing the 4 experimental groups (F = 19.4) indicated the presence of significant differences between the groups (P =. 0001). In general, the shear bond strength was greater for the composite adhesive system (¿x(-) = 5.2 +/- 2.9 MPa), followed by the 2 groups bonded with the resin-reinforced glass-ionomer adhesive and light cured for 50 seconds (¿x(-) = 3.8 +/- 1.1 MPa) and 45 seconds (¿x(-) = 3.4 +/- 2.7 MPa). On the other hand, the shear bond strength was significantly lower for the group bonded with the glass ionomer adhesive and light cured for 40 seconds only (¿x(-) = 0.4 +/- 1.0 MPa). The present findings indicated the following: (1) the resin-reinforced glass-ionomer adhesive has a significantly lower shear bond strength in the first half hour after bonding when compared to a composite resin adhesive; (2) the initial bond strength of the glass-ionomer adhesive was significantly increased by increasing the light-cure time for an additional 5 to 10 seconds; (3) the mean increase in the shear bond strength between 5 and 10 seconds of additional light curing was not significant but the variability was less with the longer cure time.

Effect of time on the shear bond strength of glass ionomer and composite orthodontic adhesives.

The purpose of this study was to compare the effects of time on the shear bond strength of a resin-reinforced glass ionomer and a composite adhesive system specifically (1) within half an hour after bonding the bracket to the tooth and (2) at least 24 hours from the time of bonding when the adhesive has achieved most of its bond strength. Ninety-one freshly extracted human molars were collected and stored in a solution of 0.1% (weight/volume) thymol. The teeth were cleaned and polished. The teeth were randomly separated into four groups: Group I, glass ionomer adhesive debonded within 30 minutes from initial bonding; Group II, glass ionomer adhesive debonded after 24 hours immersion in deionized water at 37 degrees C; Group III, composite adhesive debonded within 30 minutes from initial bonding; Group IV, composite adhesive debonded after 24 hours immersion in deionized water at 37 degrees C. The results of the analysis of variance comparing the 4 experimental groups (F = 59. 3) indicated the presence of significant differences between the 4 groups (P =.0001). In general, the shear bond strengths were significantly greater in the 2 groups debonded after 24 hours. This was true for both the resin-modified glass ionomer (x = 8.8 +/- 3.6 MPa) and the composite (x = 10.4 +/- 2.8 MPa) adhesives. On the other hand, the shear bond strengths were significantly lower in the 2 groups debonded within 30 minutes of their initial bonding. The bond strength of the resin-modified glass ionomer adhesive (x = 0.4 +/- 1.0 MPa) was significantly lower than that for the composite (x = 5.2 +/- 2.9 MPa) adhesive. The present findings indicated that the resin reinforced glass ionomer adhesive has a significantly lower initial bond strength but increased more than 20-fold within 24 hours. In comparison, the composite adhesive has a significantly larger initial bond strength that doubled within 24 hours. The clinician needs to take these properties into consideration when ligating the initial arch wires.

A survey of pregnant women's knowledge about sexual abuse.

STUDY OBJECTIVE: To assess pregnant women's understanding of sexual abuse prevalence and perpetrator characteristics. DESIGN: A multiple choice questionnaire concerning knowledge about sexual abuse prevalence and an understanding of potential perpetrators was presented to patients. Comparisons were made based on participant's age, educational status, and personal involvement in the care of children. SETTING: Prenatal clinic, Department of OB/GYN, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee. PARTICIPANTS: Patients presenting for new obstetrical evaluation (N = 289). MAIN OUTCOME MEASURES: Responses to the questionnaire. RESULTS: Less than half of the subjects correctly answered questions about sexual abuse prevalence. Only 22% of patients understood the potential youthfulness of juvenile sex offenders. Neither age nor child care responsibilities affected response. Subjects with greater than 12 years of formal education achieved significantly higher scores than those with less education, 59% of respondents were interested in more information. CONCLUSION: Pregnant women's knowledge about the dangers of sexual abuse was suboptimal in this population. The majority of patients were interested in more information.

Comparison of the debonding characteristics of two innovative ceramic bracket designs.

Two new ceramic brackets-one designed with a metal-lined arch wire slot and the other with an epoxy resin base-have been recently introduced. The new brackets are thought to combine the esthetic advantages of ceramics and the functional advantages of debonding metal brackets. The purpose of this study was to compare the following: 1) the shear bond strength of the 2 brackets, and 2) the bond failure location when the brackets are debonded with pliers. Sixty-one Clarity (3M Unitek) collapsible ceramic brackets and 66 MXi (TP Orthodontics, Inc) brackets were bonded to the teeth with the same bonding system. The Zwick Universal Test Machine (Zwick Gm bH & Co) was used to determine the shear bond strength force levels needed to debond the brackets. The appropriate pliers also were used to debond both types of brackets to determine the mode of bond failure that will be encountered clinically. After debonding, all the teeth and brackets were examined with 10x magnification. Any adhesive that remained after the bracket removal was assessed according to the Adhesive Remnant Index. The findings indicated that the shear bond strength of the Clarity ceramic brackets was significantly greater than that of the MXi ceramic brackets. However, both brackets exhibited forces that were adequate for clinical use. The Adhesive Remnant Index scores for both the shear test and the plier debonding indicated a similar bond failure pattern when the 2 ceramic brackets were compared with each other. This suggests that, when these brackets are debonded with the Weingart (Ormco) and ETM (Ormco) pliers, there was a greater tendency for most of the adhesive to remain on the enamel surface. In conclusion, the most efficient method to debond the MXi ceramic bracket is by placing the blades of the ETM 346 pliers between the bracket base and the enamel surface. On the other hand, the most efficient method of debonding the Clarity bracket is by using the Weingart pliers and applying pressure to the tiewings. When the 2 ceramic brackets were debonded as recommended here, most of the residual adhesive remained on the enamel surface, a pattern similar to the one observed previously with metal brackets. The failure at the bracket-adhesive interface decreases the probability of enamel damage but necessitates the removal of more residual adhesive after debonding.

Hemodynamic and renal effects of indomethacin in losartan-treated hypertensive individuals.

This study was undertaken to examine whether prostaglandin (PG) inhibition with indomethacin interferes with angiotensin II receptor blockade (losartan) during treatment for arterial hypertension. In a double-blind crossover design 10 patients with essential arterial hypertension and treated with losartan were randomized to supplementary treatment with indomethacin or placebo for 1 week, with a 2-week washout period interposed. At the end of each treatment period the following examinations were performed, preceded by 4 days on sodium-fixed diet: 24-h blood pressure (BP), 24-h sodium excretion (UNaV), supine BP, glomerular filtration rate (GFR), renal resistive index (RRI), extracellular fluid volume (ECV), sodium clearance (Cl(Na)), body weight, peripheral blood flow (PBF), and plasma concentrations of aldosterone, renin (PRC), and atrial natriuretic peptide (ANP). Indomethacin did not change BP. Indomethacin increased weight (P < .05) and ECV (P < .05). A nonsignificant decrease in UNaV was seen after indomethacin, as in 24-h Cl(Na). Conversely, in the laboratory in the supine position Cl(Na) increased after indomethacin (P = .05). Indomethacin increased plasma ANP (P < .01). No changes were observed in GFR, RRI, PBF, PRC, or plasma aldosterone. Thus indomethacin did not attenuate the antihypertensive effect of losartan, neither was peripheral blood flow affected. Indomethacin caused sodium retention in the nonresting situation, which was not counterbalanced by the increased Cl(Na) in the resting supine position. The observed changes during prostaglandin (PG) inhibition seem most likely due to lack of PG "protection" of renal function, when the sympathetic nervous system is activated throughout the day.

Guilt, shame, and symptoms in children.

The authors asked whether evidence could be found for adaptive or maladaptive aspects of guilt and shame in 5-12-year-old children (44 boys, 42 girls). Children completed semiprojective and scenario-based measures thought to assess shame, guilt, or both. Their parents (N = 83) completed the Child Behavior Checklist to assess child symptoms. Shame and projective guilt were related to symptoms; they also were associated with self-blame and attempts to minimize painful feelings. Scenario-based guilt was related to fewer symptoms in boys but to greater symptoms in girls. This measure of guilt reflected concerns with adhering to standards, expressing empathy, and taking appropriate responsibility. Discussion focuses on possible origins of differential symptom-emotion links in boys and girls as well as measurement implications.

Rubella serology in mentally retarded adults.

BACKGROUND: Rubella and congenital rubella syndrome remain a problem in the United States; institutionalized individuals are at higher risk. We assessed demographic variables and rubella serology in a population of institutionalized adults with mental retardation. METHODS: Subjects were 181 institutionalized adults with mental retardation. We reviewed charts to determine patient's age, sex, race, and fertility status (if female), cause of mental retardation, and rubella history. Serologic testing to determine rubella immunity was done. RESULTS: We found that 26.4% of subjects were nonimmune. Sex, cause of mental retardation, and history of rubella vaccination were not related to serologic immunity status. Of the 29 fertile female subjects, 8 (27.6%) were nonimmune to rubella. CONCLUSION: Subjects with unknown immunization status had a similar serologic profile to those whose medical records indicated immunization. Neither history of infection nor immunization was predictive of serology status.

Evaluation of a new light-cured orthodontic bonding adhesive.

The purpose of this study was to compare a new light-cured bonding system that used a hybrid adhesive containing a resin reinforced glass ionomer (Fuji Ortho LC, GC America, Inc.) with a more traditional light-cured bonding system (Transbond, 3M Unitek) that contained resin material only. Seventy-five recently extracted human molars were collected and stored in a solution of 0.1% (weight/volume) thymol. The teeth were randomly separated into five groups of 15 molars each: Group I--using Transbond adhesive system with the enamel etched and dried before bonding. Group II--using Fuji Ortho LC (FOLC) adhesive system with no etch and the enamel wet with water before bonding. Group III--using FOLC adhesive system with the enamel etched and wet with water before bonding. Group IV--using FOLC adhesive system with no etch and the enamel wet with saliva before bonding. Group V--using FOLC adhesive system with the enamel etched and wet with saliva before bonding. The shear bond strength was performed after thermal cycling between 5 degrees +/- 2 degrees C and 50 degrees +/- 2 degrees C for a total of 2000 cycles with the Zwick test machine (Zwick Gm bH & Co.). After debonding, the teeth and brackets were examined under x10 magnification to evaluate the site of bond failure and the presence of residual adhesive. The analysis of variance was used to determine whether significant differences existed between the various groups. The findings indicated that there were no statistically significant differences among the three experimental groups I, III, and V that had the enamel surface etched before bonding, regardless of the adhesive used or the enamel surface contamination with water or saliva. On the other hand, the two experimental groups that did not have the enamel etched before bonding (II and IV) had significantly lower bond strengths. In conclusion, etching the enamel surface is a critical variable that affects shear bond strength as well as bond failure location when using the new adhesive system.

Comparison of shear bond strength and surface structure between conventional acid etching and air-abrasion of human enamel.

Recently, air-abrasion technology has been examined for potential applications within dentistry, including the field of orthodontics. The purpose of this study was to compare the traditional acid-etch technique with an air-abrasion surface preparation technique, with two different sizes of abrading particles. The following parameters were evaluated: (a) shear bond strength, (b) bond failure location, and (c) enamel surface preparation, as viewed through a scanning electron microscope. Sixty extracted human third molars were pumiced and divided into three groups of 20. The first group was etched with a 37% phosphoric acid gel for 30 seconds, rinsed for 30 seconds, and dried for 20 seconds. The second and third groups were air-abraded with (a) a 50 microm particle and (b) a 90 microm particle of aluminum oxide, with the Micro-etcher microabrasion machine (Danville Engineering Inc.). All three groups had molar stainless steel orthodontic brackets bonded to the buccal surface of each tooth with Transbond XT bonding system (3M Unitek). A Zwick Universal Testing Machine (Calitek Corp.) was used to determine shear bond strengths. The analysis of variance was used to compare the three groups. The Adhesive Remnant Index (ARI) was used to evaluate the residual adhesive on the enamel after bracket removal. The chi square test was used to evaluate differences in the ARI scores among the groups. The significance for all tests was predetermined at p < or = 0.05. The results indicated that there was a significant difference in shear bond strength among the three groups (p = 0.0001). The Duncan Multiple Range test showed a significant decrease in shear bond strength in the air-abraded groups. The chi square test revealed significant differences among the ARI scores of the acid-etched group and the air-abraded groups (chi(2) = 0.0001), indicating no adhesive remained on the enamel surface after debonding when air-abrasion was used. In conclusion, the current findings indicate that enamel surface preparation using air-abrasion results in a significant lower bond strength and should not be advocated for routine clinical use as an enamel conditioner at this time.

Evaluation of debonding characteristics of a new collapsible ceramic bracket.

A new collapsible ceramic bracket designed with a metal-lined arch wire slot has been recently introduced. The bracket also incorporates a vertical slot designed to help create a consistent bracket failure mode during debonding. The new bracket is thought to combine the esthetic advantages of ceramics and the functional advantages of debonding metal brackets. The purpose of this study was to compare (1) the shear bond strength of the new collapsible bracket with a traditional ceramic bracket, (2) the compressive force required to debond the new bracket from the enamel surface with that needed to debond a traditional metal bracket, and (3) the bond failure location when debonding the new bracket and a traditional ceramic bracket when pliers are used. Sixty-one Clarity collapsible ceramic brackets, 41 Transcend 6000 brackets, and 21 Victory Series metal brackets were bonded to the teeth with the same bonding system. The Zwick Universal Test Machine was used to determine the shear bond strength of 21 teeth bonded with the new bracket and 20 teeth bonded with the Transcend brackets. The same testing device was used to determine the compression force levels needed to debond 20 collapsible brackets and 21 metal brackets. Pliers were used to debond both the new ceramic brackets and Transcend brackets to determine the mode of bond failure. After debonding, all teeth and brackets were examined under 10x magnification. Any adhesive remaining after bracket removal was assessed according to the Adhesive Remnant Index (ARI). The findings indicated that the shear bond strength of the new Clarity ceramic bracket was comparable to that of a conventional ceramic bracket. Similarly, there were no significant differences in the results of the compression tests comparing the magnitude of forces needed to deform and debond both the new ceramic and metal brackets. The ARI scores for both the shear and compression tests indicated a similar bond failure pattern when the new collapsible brackets were compared with either the conventional ceramic or metal brackets. On the other hand, the chi-square test results indicated that, when debonding pliers were used, there was a significantly greater incidence of an ARI score of 1 with the collapsible brackets. This indicated that, when debonding the new brackets with the Weingart pliers, there was a greater tendency for most of the adhesive to remain on the enamel surface. In conclusion, the main advantage of the Clarity ceramic brackets is that they can be debonded in the same manner as metal brackets. When the new ceramic brackets are debonded with the Weingart pliers, most of the residual adhesive remained on the enamel surface, a pattern that is similar to the one observed with metal brackets. The failure at the bracket-adhesive interface decreases the probability of enamel damage but necessitates the removal of more residual adhesive after debonding.

[Prevalence of left ventricular hypertrophy in Danish patients with hypertension]. / Forekomsten af venstresidig hjertehypertrofi hos danske personer med hypertension.

The aim of this investigation was to study the prevalence of left ventricular hypertrophy (LVH) in a hypertensive population with reference to a normotensive control group. From the general population, 3498 men and women aged 35, 45, 55 and 65 years old were invited to a health examination. Participants with blood pressure above 160 mmHg systolic and/or 95 mmHg diastolic or participants currently taking antihypertensive medication or having done so during the previous six months were asked to undergo an echocardiographic examination. Controls were randomly selected from the same population. Of 552 participants in the final study population, 194 were normotensive controls and 358 were in the hypertensive group. Echocardiographic measurements were made according to the "Penn" conventions and indexed for body surface. Cutoff values for LVH were 134 grams per m2 for males and 102 grams per m2 for women. Overall, we found that the prevalence of 1 VH was 14%/20% (men/women) in normotensives and 25%/26% in hypertensives (p < 0.01). By subdivision in age and sex groups we found that the relation between normotensives and hypertensives was significant in the age group of 65 years (p < 0.02 for males and p < 0.05 for females). The association between blood pressure and 1 VH in the general population is weak. 1 VH is only significantly more frequent among hypertensives as compared to normotensives in older people.

Evaluation of Scotchbond Multipurpose and maleic acid as alternative methods of bonding orthodontic brackets.

Damage to the enamel surface during bonding and debonding of orthodontic brackets is a clinical concern. Alternative bonding methods that minimize enamel surface damage while maintaining a clinically useful bond strength is an aim of current research. The purpose of this study was to compare the effects on bond strength and bracket failure location of two adhesives (System 1+ and Scotchbond Multipurpose, 3M Dental Products Division) and two enamel conditioners (37% phosphoric acid and 10% maleic acid). Forty-eight freshly extracted human premolars were pumiced and divided into four groups of 12 teeth, and metal orthodontic brackets were attached to the enamel surface by one of four protocols: (1) System 1+ and phosphoric acid, (2) Scotchbond and phosphoric acid, (3) System 1+ and maleic acid, and (4) Scotchbond and maleic acid. After bracket attachment, the teeth were mounted in phenolic rings and stored in deionized water at 37 degrees C for 72 hours. A Zwick universal testing machine (Zwick GmbH & Co.) was used to determine shear bond strengths. The residual adhesive on the enamel surface was evaluated with the Adhesive Remnant Index. The analysis of variance was used to compare the four groups. Significance was predetermined at p < or = 0.05. The results indicated that there were no significant differences in bond strength among the four groups (p = 0.386). The results of the Chi square test, evaluating the residual adhesives on the enamel surfaces, revealed significant differences among the four groups (mean 2 = 0.005). A Duncan multiple range test revealed the difference occurred between the phosphoric acid and maleic acid groups, with maleic acid having bond failures at the enamel-adhesive interface. In conclusion, the use of Scotchbond Multipurpose and/or maleic acid does not significantly effect bond strength, however, the use of maleic acid resulted in an unfavorable bond failure location.

Bond strength following the application of chlorhexidine on etched enamel.

The purpose of this study was to determine whether the application of chlorhexidine to etched enamel affects the shear bond strength and bracket/adhesive failure modes of orthodontic brackets. Forty recently extracted third molars were cleaned divided into two groups of twenty. The first group was etched with a 37% phosphoric acid gel, and a sealant was applied containing a chlorhexidine varnish. Stainless steel orthodontic brackets were bonded using the Transbond XT bonding system (3M/Unitek). Teeth in the second group were etched and bonded using the same bonding system but without chlorhexidine. A Zwick Universal Testing Machine was used to determine shear bond strengths. There were no significant differences in bond strengths between the chlorhexidine treated teeth (= 11.8 +/- 2.1 MPa) and the controls (= 12.4 +/- 3.1 MPa) (p = 0.129). The Chi Square test evaluating the residual adhesive on the enamel surfaces showed no significant differences (P = 0.136) between the two groups evaluated. The use of a primer containing chlorhexidine does not significantly affect shear bond strength nor the fracture site (bond failure location).

Evaluation of the shear bond strength of different ceramic bracket base designs.

The purpose of this study was to compare the Ceramaflex bracket with a traditional ceramic orthodontic bracket with regard to shear bond strength and bond failure location. Forty newly extracted human premolars were randomly divided into two groups. Twenty Ceramaflex brackets (TP Orthodontics Inc, LaPorte, Ind) and 20 Transcend 6000 brackets (Unitek Corp, Monrovia, Calif) were bonded to the teeth using the same bonding system (Right On, TP Orthodontics Inc, LaPorte, Ind). A Zwick Universal Test machine (Zwick Gm bH & Co, Ulm, Germany) was used to determine the shear bond strength for each bracket. After debonding, the teeth and brackets were examined under 10x magnification. After debonding, the amount of resin material adhering to the enamel surface was assessed according to the Adhesive Remnant Index (ARI). The results of this study suggest that Ceramaflex brackets have a significantly lower bond strength than traditional ceramic brackets. On the other hand, the bond failure location of the Ceramaflex bracket was consistently more favorable, i.e., occurring at the ceramic bracket-polycarbonate base.

Effect of varying etching times on the bond strength of ceramic brackets.

Damage to the enamel surface when debonding orthodontic ceramic brackets has been a clinical concern. Ideally, bond failure at the bracket-adhesive interface should occur without damaging the enamel surface. The purpose of this study was to determine the shear bond strength and debonding failure modes of ceramic brackets with varying etching times. Sixty freshly extracted human premolars were pumiced and divided into six groups of 10 teeth. Each group was assigned an etching time interval of either 30, 20, 15, 10, 5, or 0 seconds with 37% phosphoric acid. Ceramic orthodontic brackets were bonded to each etched tooth by using the same orthodontic bonding system. The teeth were mounted in phenolic rings and stored in deionized water at 37 degrees C for 48 hours. A Zwick universal testing machine (Zwick GmbH and Co., Ulm, Germany) was used to determine shear bond strengths. The residual adhesive on the enamel surface was evaluated with the Adhesive Remnant Index. The results of the analysis of variance indicated that there were significant differences in bond strengths between the various etching times (p=0.0001). The Duncan multiple range test revealed that the 5-second and no etch group exhibited significantly lower bond strengths. The results of the Chi square test evaluating the residual adhesives on the enamel surface also revealed significant differences (p=0.0001). However, when the 5- and 0-second groups were dropped from the test, the Chi square test revealed no significant differences between the 30-, 20-, 15-, and 10-second groups (p=0.211). In conclusion, decreasing etching time between 30 and 10 seconds does not significantly affect either bond strength or the site of bond failure.

Prevalence of left ventricular hypertrophy in a hypertensive population.

AIMS: This investigation was set up to study the prevalence of left ventricular hypertrophy in a hypertensive population with reference to a normotensive control group. From the general population 3498 men and women aged 35, 45, 55 and 65 years old were invited to a health examination. Participants with blood pressure above 160 mmHg systolic or 95 mmHg diastolic or those taking antihypertensive medication or having done so during the previous 6 months were asked to undergo an echocardiographic examination. Normotensive controls were randomly selected from the same population. Of 552 participants in the final study population, 194 were normotensive controls and 358 were in the hypertensive group. Echocardiographic measurements were made according to the Penn conventions and indexed for body surface. Cut-off values for left ventricular hypertrophy were 134 g.m-2 for males and 102 g.m-2 for women. RESULTS: Overall, the prevalence of left ventricular hypertrophy was 14%/20% (men/women) in normotensives and 25%/26% in hypertensives (P < 0.01). After subdivision by age and sex, there was a significant difference in the prevalence of left ventricular hypertrophy between normotensives and hypertensives only in the 65-year-old group (P < 0.02 for males and P < 0.05 for females). CONCLUSIONS: The association between blood pressure and left ventricular hypertrophy in the general population is weak. Left ventricular hypertrophy is only significantly more frequent among hypertensives as compared to normotensives in older people.