Zirconia crown performance in primary maxillary anterior teeth: a retrospective photographic and radiographic cohort study.

PURPOSE: This retrospective cohort observational study evaluated marginal integrity, gingival health and aesthetics of zirconia crowns (ZC) placed on primary maxillary anterior teeth at 6- to over 30-month follow-up visits. METHODS: Two independent raters evaluated radiographic and photographic findings in 131 ZC placed in 36 children aged 24.8-62.2 months (median = 40.6) who had at least one recall visit 6 months after placement. Follow-up periods were stratified into three levels: long, intermediate and short. Associations between crown performance and crown brands, follow-up periods, treatment performed under general anaesthesia or sedation and previous pulpotomy were investigated by ordinal logistic regression. RESULTS: Follow-up ranged from 6 to 33.8 months (average: 13.5 months). Marginal integrity was highly rated in 82.4% of the teeth. No gingivitis was found in 35% of the teeth, 58% showed mild gingivitis and 7% showed moderate gingivitis (p = 0.06). Colour match and crown contour were rated very high in 55% of the cases. Marginal integrity and periodontal health differed between cases performed under general anaesthesia and those performed under sedation (p = 0.03 and p = 0.003, respectively). Pulpotomized teeth showed worse colour matching with the adjacent teeth than non-pulpotomized teeth (p = 0.03). CONCLUSIONS: Our findings suggest that ZC comprise a satisfactory treatment option for carious primary maxillary incisors, presenting good overall marginal integrity, gingival health, and aesthetics.

Characterization of compact-toroid injection during formation, translation, and field penetration.

We have developed a compact toroid (CT) injector system for particle refueling of the advanced beam-driven C-2U field-reversed configuration (FRC) plasma. The CT injector is a magnetized coaxial plasma gun (MCPG), and the produced CT must cross the perpendicular magnetic field surrounding the FRC for the refueling of C-2U. To simulate this environment, an experimental test stand has been constructed. A transverse magnetic field of ∼1 kG is established, which is comparable to the C-2U axial magnetic field in the confinement section, and CTs are fired across it. On the test stand we have been characterizing and studying CT formation, ejection/translation from the MCPG, and penetration into transverse magnetic fields.

Development of a magnetized coaxial plasma gun for compact toroid injection into the C-2 field-reversed configuration device.

A compact toroid (CT) injector was developed for the C-2 device, primarily for refueling of field-reversed configurations. The CTs are formed by a magnetized coaxial plasma gun (MCPG), which consists of coaxial cylindrical electrodes and a bias coil for creating a magnetic field. First, a plasma ring is generated by a discharge between the electrodes and is accelerated by Lorenz self-force. Then, the plasma ring is captured by an interlinkage flux (poloidal flux). Finally, the fully formed CT is ejected from the MCPG. The MCPG described herein has two gas injection ports that are arranged tangentially on the outer electrode. A tungsten-coated inner electrode has a head which can be replaced with a longer one to extend the length of the acceleration region for the CT. The developed MCPG has achieved supersonic CT velocities of ∼100 km/s. Plasma parameters for electron density, electron temperature, and the number of particles are ∼5 × 10(21) m(-3), ∼40 eV, and 0.5-1.0 × 10(19), respectively.

Long-path second-harmonic interferometer with nanosecond time resolution: reliable diagnostic tool for electron density measurement in pulsed plasma devices.

We describe the performance of a second-harmonic interferometer (SHI) to measure, on an optical path exceeding 12 m, the electron plasma density of two plasmoids formed in separate theta-pinch chambers and then merged in a central compression chamber after undergoing acceleration and compression. The excellent mechanical stability and a time resolution better than 50 ns suggest the application of SHI, especially in pulsed plasma devices with limited optical accesses.

Anterior crowns for primary anterior teeth: an evidence based assessment of the literature.

AIM: To review the literature concerning the restoration of primary anterior teeth with pre-formed crowns or with the use of crown forms. METHODS: A search of the dental literature was made electronically using key words: crowns, primary teeth, anterior teeth, strip crowns, stainless steel crowns, veneered crowns, (a)esthetic, restorative. All papers were reviewed and assessed for their relevance to paediatric dentistry and then graded according to a set or predetermined criteria. These criteria were used to identify those reports that met 100% of the criteria, graded A; 75% grade B1; more than 50% graded B2 and all others graded C. RESULTS: There were 90 papers in all using the key words. Of these none were rated grade A; B1 or B2 and all remaining valid papers (not single restoration case reports), 50 were graded C. Failure rates varied between 0% and 50% for strip crowns; 32-39% for veneered metal crowns. The review indicated there is some evidence as to the efficacy and value of using anterior primary teeth crowns because of the improved aesthetics that they achieve. There was an obvious lack of prospective well controlled studies and more studies are needed. CONCLUSION: No clinical studies concerning anterior crowns on primary teeth were identified that met all or even a majority of criteria, indicating that there was little, good scientific support for any of the techniques which clinicians have utilized for many years to restore primary anterior teeth. While a lack of strong clinical data does not preclude the use of these techniques it points out the strong need for well designed, prospective clinical studies to validate the use of these techniques.

Anterior esthetic fixed appliances for the preschooler: considerations and a technique for placement.

One of the pediatric dentist's greatest restorative challenges is the esthetic rehabilitation of a young toddler who has suffered multiple tooth loss subsequent to rampant early childhood caries or extensive dental trauma. An anterior esthetic appliance may be used to replace lost teeth. The most decisive factor for placing an anterior esthetic appliance is parental desire. Other considerations include: space maintenance, masticatory function, speech development, and tongue habits. However, there is no strong evidence that early loss of maxillary incisors will have any significant, long lasting effect on the growth and development of the child. This paper discusses in detail one type of fixed anterior esthetic appliance and the considerations to be made when deciding when and why to place them.

Total testosterone and DHEAS levels as predictors of androgen-secreting neoplasms: a populational study.

Androgen excess affects between 2% and 10% of women. While the majority of these patients suffer from polycystic ovary syndrome, a few present with an androgen-secreting neoplasm. An elevated circulating total testosterone level and dehydroepiandiosterone sulfate (DHEAS) level have been proposed as screening methods for detecting ovarian and adrenal androgen-secreting neoplasms, respectively. To determine the predictive value of these tests for androgen-secreting tumors in a population of consecutive hyperandrogenic patients, we studied 478 consecutive untreated hyperandrogenic patients presenting over a ten-year period (1987-97). All had at least two of the following features: (1) oligomenorrhea (i.e. cycles > 35 days or < 8 cycles/year), (2) hyperandrogenemia (i.e. a total or free testosterone, or DHEAS > 95th percentile of controls), or (3) hirsutism (i.e. a modified Ferriman-Gallwey score > or = 6). None of these patients had a prior diagnosis of an androgen-secreting neoplasm. Basal levels of testosterone and DHEAS were determined in all patients, with transvaginal sonography and an adrenal computed tomography scan in select individuals. Of the 478 patients included, 65% had hirsutism and oligomenorrhea; 20% had hyperandrogenic oligomenorrhea; and 15% had hirsutism and hyperandrogenemia, without overt oligomenorrhea. Overall, 11 (2.3%) patients had a total testosterone > 8.7 nmol/l (250 ng/dl), of which one actually had an androgen-secreting neoplasm (i.e. true-positive). This postmenopausal patient presented with rapidly progressive virilization, and demonstrated an ovarian hilar cell tumor at surgery. The calculated sensitivity of an elevated testosterone level (> 8.67 nmol/l) for a neoplasm was 100% (1/1), the specificity was 98% (467/477), and the negative predictive value was 100% (467/467), but the positive predictive value was only 9% (1/11). Ten subjects had DHEAS levels > 16.3 mumol/l (6000 ng/ml), and none was diagnosed with an adrenocortical tumor. Although the sensitivity and positive predictive value of a high DHEAS for a neoplasm could not be calculated due to the absence of a test case, the specificity was 98% (468/478) and the negative predictive value was 100% (468/468). These data suggest that the measurement of testosterone and DHEAS is not a cost-effective method of screening for these tumors, due to the low frequency of the disorder and the fact that clinical evaluation alone is often sufficient screening.

Prevalence of the polycystic ovary syndrome in unselected black and white women of the southeastern United States: a prospective study.

Estimates of the prevalence of the polycystic ovary syndrome (PCOS) in the general population have ranged from 2-20%. The vast majority of these reports have studied White populations in Europe, used limited definitions of the disorder, and/or used bias populations, such as those seeking medical care. To estimate the prevalence of this disorder in the United States and address these limitations, we prospectively determined the prevalence of PCOS in a reproductive-aged population of 369 consecutive women (174 White and 195 Black; aged 18-45 yr), examined at the time of their preemployment physical. Body measures were obtained, and body hair was quantified by a modified Ferriman-Gallwey (F-G) method. All exams were initially performed by 2 trained nurses, and any subject with an F-G score above 3 was reexamined by a physician, the same for all patients. Of the 369 women, 277 (75.1%) also agreed to complete a questionnaire and have additional blood drawn. Subjects were studied regardless of current estrogen/progestin hormonal use (28.5%). PCOS was defined as 1) oligoovulation, 2) clinical hyperandrogenism (i.e. hirsutism) and/or hyperandrogenemia, and 3) exclusion of other related disorders, such as hyperprolactinemia, thyroid abnormalities, and non-classic adrenal hyperplasia. Hirsutism was defined by a F-G score of 6 or more, and hyperandrogenemia was defined as a total or free testosterone, androstenedione, and/or dehydroepiandrosterone sulfate level above the 95th percentile of control values [i.e. all eumenorrheic women in the study, who had no hirsutism (F-G < or = 5) or acne and were receiving no hormonal therapy; n = 98]. Considering all 369 women studied, White and Black women had similar mean ages (29.4 +/- 7.1 and 31.1 +/- 7.8 yr, respectively), although White women had a lesser body mass than Black women (24.9 +/- 6.1 vs. 29.2 +/- 8.1 kg/m2, respectively; P < 0.001). Of these 7.6%, 4.6%, and 1.9% demonstrated a F-G score of 6 or more, 8 or 10, respectively, and there was no significant racial difference, with hirsutism prevalences of 8.0%, 2.8%, and 1.6% in Whites, and 7.1%, 6.1%, and 2.1% in Blacks, respectively. Of the 277 women consenting to a history and hormonal evaluation, 4.0% had PCOS as defined, 4.7% (6 of 129) of Whites and 3.4% (5 of 148) of Blacks. In conclusion, in our consecutive population of unselected women the prevalence of hirsutism varied from 2-8% depending on the chosen cut-off F-G score, with no significant difference between White and Black women. Using an F-G score of 6 or more as indicative of hirsutism, 3.4% of Blacks and 4.7% of Whites had PCOS as defined. These data suggest that PCOS may be one of most common reproductive endocrinological disorders of women.

Idiopathic hirsutism: an uncommon cause of hirsutism in Alabama.

OBJECTIVE: To determine the prevalence of idiopathic hirsutism among a population of consecutive hirsute patients. DESIGN: Prospective cohort study. SETTING: University-based clinic. PATIENT(S): Premenopausal women with a complaint of hirsutism who were not receiving hormonal therapy. INTERVENTION(S): Evaluations for total and free testosterone, (T), 17-hydroxyprogesterone (17-HP), and DHEAS serum levels. MAIN OUTCOME MEASURE(S): Ovulatory function in women with cycles of < or =35 days in length was assessed with a basal body temperature (BBT) calendar and day 22-24 progesterone levels. RESULT(S): Of 132 consecutive hirsute women studied, 68 had cycles of >35 days in length. Of the remaining 64 patients, 25 also had oligo/anovulation by BBT and day 22-24 progesterone level. Of the 39 patients with hirsutism and regular ovulatory function, 22 had total and free T and DHEAS levels within normal limits. CONCLUSION(S): If idiopathic hirsutism is defined by the presence of hirsutism, regular ovulation, and normal androgen levels, only 17% of consecutive hirsute patients can be diagnosed with the disorder. Alternatively, if idiopathic hirsutism is based solely on the presence of hirsutism and regular ovulation, regardless of androgen levels, then 29% of the total hirsute population can be considered as having idiopathic hirsutism. Importantly, 40% of hirsute patients with a history of "regular cycles" were actually oligo/anovulatory, indicating the need to objectively assess ovulatory function in such patients.

Pit and fissure sealant application: updating the technique.

Dental sealants have proved an effective way to prevent caries development. The authors discuss available options in sealant materials and placement. They also outline key points in sealant application.

Managing a peripheral ossifying fibroma.

The Peripheral Ossifying Fibroma is an inflammatory lesion which most often appears in twenty-five to thirty-four-year-old females. It averages 1.0 cm at its greatest dimension. This case reports a seven-year-eight-month-old female who presented with a peripheral ossifying fibroma lesion which measured 2.7 cm by 1.5 cm by 1.0 cm. A review of peripheral ossifying fibroma, and the management and postsurgical sequelae of this child are discussed.

Failure strength of four veneered primary stainless steel crowns.

The purpose of this study was to determine the amount of shear force required to fracture or dislodge the veneered facings of four commercially available veneered primary incisor stainless steel crowns (SSC) and to characterize the veneer failures. Forty Unitek SSCs (#4 left central incisor) were shaped to fit a master die and then 10 each were mailed to four commercial dental laboratories that produce veneered SSCs. The resulting four types of crowns tested were: Cheng Crowns (CC), [Peter Cheng Orthodontic Laboratory]; Kinder Krowns (KK) [Mayclin Dental Studio, Inc]; NuSmile Primary Crowns (NC), [Orthodontic Technologies, Inc]; and Whiter Biter Crown II (WB), [White Bite Inc]. Each crown was cemented onto a standardized die and then thermocycled at 4 degrees C and 55 degrees C for 500 1-min cycles. Each die was then placed into a custom holder on the Instron (Model 4204) testing machine. A force was applied at the incisal edge of the veneer at 148 degrees, (the primary inter-incisal angle), with a crosshead speed of 1 mm/min until the veneer fractured or was dislodged. The mean force (N) required +/- SD to produce failure was, respectively: KK (397.2 +/- 53.0); NC (447.2 +/- 78.5); CC (511.9 +/- 83.4); WB (686.5 +/- 181.4). Analysis of variance (ANOVA) indicated significance at P < 0.0001. A Scheffe's post hoc comparison demonstrated that the Whiter Biter (WB) group required significantly (alpha = 0.05) more force for failure than the other three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Attitudes of program directors toward women in pediatric dentistry training programs.

The number of women entering pediatric dentistry graduate programs is increasing. A formal survey was conducted in the fall of 1990 to determine what impact, if any, this increase is having on the programs. The survey sample consisted of the 57 pediatric dentistry graduate program directors from the United States and Canada. The survey form included program data about gender distribution in the current and previous classes, and female faculty distribution within the programs. The survey requested information about the attitudes of various groups of individuals who interacted with the residents relative to the gender of the resident and again, relative to whether the resident was pregnant. Inquiry was made concerning maternity leave policies and selected treatment scenarios involving pregnant residents. Finally, questions were asked about motivational factors, personal priorities, and policy change for female vs. male residents. Fifty forms were returned for a return rate of 88%. The 48 forms analyzed revealed that 52% of current classes are female and 51% of applicants for 1991 were female. Women comprise 23% of full-time and 26% of part-time faculty. There was no single issue perceived by program directors as a group to be a significant concern or problem relating to gender. Program directors would consider removing pregnant females from contact with combative patients (83%) and environmental hazards (85%), but fewer would consider removing them from contact with for HIV+ or Hb+ patients.

The experiences of women pediatric dental residents: a survey.

A survey of 430 female pediatric dentists in the United States determined concerns and experiences they had during their advanced training programs. The return rate was 54%. Up to 83% (24) of the women who were pregnant during their residencies asked not to be exposed to certain environmental hazards during pregnancy and the postpartum period. They requested that program directors establish policies on known environmental hazards. Eighty-eight women (41%) commented that programs should offer flexible, preestablished and preannounced maternity leave policies. Survey respondents also expressed concerns about personal safety (5%), the lack of female role models (9%), and the need for more information on business management (30%). When the women were analyzed according to age, the following were significant (P less than .05): professional acceptance was of greatest concern to women ages 41-48; pregnancy and maternity leave, and balancing career with parenthood, significantly concerned women 25-32; and women ages 33-40 said business management was the issue causing the greatest frustration as a practicing pediatric dentist. While most respondents felt that they have the same professional opportunities as men, their greatest frustrations are a lack of acceptance by the professional and lay communities and trying to balance a career and motherhood.

Kinetic analyses demonstrate that the equilibrium assumption does not apply to [125I]endothelin-1 binding data.

The kinetics of [125I]Endothelin-1 ([125I]ET-1) binding were studied using membranes from rat heart, rat lung, rat brain, and porcine vascular smooth muscle at 37 degrees C in 0.05M Tris-HCl buffer (pH = 7.4). The dissociation half-life (t1/2, diss.) for bound [125I]ET-1 was in excess of 30 hours for each tissue studied. Equilibrium-time requirements for proper Scatchard analysis of [125I]ET-1 were also far in excess of 30 hours for each tissue. These data suggest that determination of dissociation constants, Kd, and receptor concentrations, Bmax, by conventional Scatchard analysis is not feasible with [125I]ET-1. Kinetic analyses may provide a more accurate means for determining [125I-ET-1] binding characteristics including Kd and Bmax.

Managing occlusal surfaces of young permanent molars.

The practice of restoring occlusal surfaces of young permanent teeth with just amalgam or waiting and watching for caries to occur is outdated. Today, there are several treatment options.

Parental attitudes toward behavior management techniques used in pediatric dentistry.

Previous studies evaluating parents' attitudes toward behavior management techniques used in pediatric dentistry suggest that parental attitudes are generally negative. The purpose of this study was to reexamine this issue by comparing the effect of prior explanation on parental acceptance of eight behavior management techniques. Videotaped segments were made of children's dental appointments containing examples of eight behavior management techniques. One group of 40 parents viewed a videotape which provided no explanation for each technique before it was shown. Another group of 40 parents viewed a videotape which provided no explanation of the techniques. The parents then were asked to rate the acceptability of each technique using a visual analogue scale. Results indicated that the informed parents were significantly more accepting of behavior management techniques than the uninformed parents but both groups were generally positive about the techniques studied. Further, parents reporting greater stress were less accepting of the techniques studied.