Chemomechanical caries removal--a clinical evaluation

The aim of this investigation was to evaluate the efficacy and convenience of decayed dentine removal with N-monochloro-DL-2 aminobutyrate (CARIDEX) in all classes of cavities. Fifty-seven patients, each with two teeth having similarly sized carious cavities, participated in this study. One cavity in each patient was treated with the chemomechanical CARIDEX technique and the other cavity was treated with conventional mechanical drilling. The cavities were restored with either amalgam, composite or glass ionomer restorative materials. The time taken for access and caries removal was noted and the efficacy of caries removal with each technique was evaluated. The chemomechanical caries removal technique was effective in removing 90-100% of decayed dentine in 98% of the cavities treated. Multiple regression adjusted access and caries removal time to account for volume of caries removed. This adjusted time was operator dependent, and ranged from 4 to 10 minutes longer for CARIDEX than for the conventional technique. Ninety-three per cent of patients preferred the chemomechanical method of caries removal over the conventional technique (highly significant P less than 0.001). Even though the chemomechanical removal of caries is slower than the conventional technique, the efficacy of CARIDEX and its high patient acceptance provides a viable alternative method for dentinal caries removal in all classes of cavities.

Managing orthodontic data on a small computer

A literature survey of file management, relational database management, and network/hierarchical database management systems led to selection of dBASE III to manage patient records on an IBM PC in the Department of Orthodontics at the Louisiana State University School of Dentistry. The versatility of this system's internal language enables ad hoc analysis of clinical and personal data to meet both anticipated and unanticipated management and scientific needs.

Using perceived exertion to prescribe and monitor exercise training heart rate

We examined whether feedback of heart rate (HR) or HR combined with ratings of perceived exertion (RPE and HR) during a graded exercise test (GXT) and during early trials of field training would reduce the errors commonly seen when training heart rate range (THR) is self-monitored by participants. Asymptomatic males (n = 24) were tested on a Balke treadmill protocol in a randomized, between-groups design under control conditions or conditions where feedback about HR or HR combined with RPE were given as age-predicted THR was approximated. This was followed on alternating days by three field trials of an 800-m jog where errors between prescribed and attained THR were fed back to each subject. A priori 95% confidence intervals for the first field trial showed that signed (algebraic) error for the HR combined with RPE condition (+3 bts/min) was less than for controls (+23.5 bts/min). Feedback of HR alone was no different from the control condition. All groups showed increased accuracy (P less than .05) by the third field trial [absolute error: T1 (18 bts/min) to T3 (9.6 bts/min); signed error: T1 (+14 bts/min) to T3 (+4 bts/min)]. Our results suggest feedback of HR combined with RPE during a GXT may reduce an overshoot in THR during the first of subsequent exercise sessions. Feedback of HR alone appeared sufficient to further reduce THR errors after a third exercise session in the field. The procedures used may have practical importance for sedentary, unfit, or diseased individuals where conservative HR prescriptions are desirable but electronic monitoring is not feasible or cost effective.

The effectiveness of opaquer and color-modifier materials: a laboratory study

New, direct bonding composite resin products are available for esthetic and restorative dentistry. As in vitro study was conducted to evaluate the stain-masking effectiveness of 57 opaquers or color modifiers. Results of the testing on 265 specimens are reported, ranging from minimal to excellent masking.

Sensitometric and image analysis of T-grain film

The new Kodak T-grain film is the result of a new technology that makes fast films with high image resolution. The purpose of the investigation was to determine the sensitometric properties and image quality of a T-grain film (T-Mat G) and also to compare this film with a green-sensitive orthochromatic film (Ortho G) and a blue-sensitive film (XRP). The criteria for film evaluation were relative speed, average contrast, exposure latitude, and image resolution. The results showed that the T-Mat G film is twice as fast as the X-Omat RP film and, one and one-third times as fast as the Ortho G film. T-Mat G also produces high resolution and high contrast. This is contrary to the widely held notion that speed is inversely proportional to image quality.

The predictive validity of the functional capacities evaluation

This study tested the predictive validity of the Functional Capacities Evaluation (FCE), which included the following three components: a Medical History Review, a Client Activity Interview, and the Smith Physical Capacities Evaluation (SMITH-PCE) as the performance component. The FCE is used in conjunction with the Physical Demands and Environmental Conditions specified by the U.S. Department of Labor to predict a subject's ability to return to work. The study used a random sample of 52 subjects. An employment questionnaire served as a criterion measure of predictive validity. The data from the questionnaires were compared with predictions from the evaluations, and a lambdab test was applied to the data. Results suggested that for the sample analyzed, trained registered occupational therapists could use the FCE to predict a client's ability to return to work more accurately. The study was limited in that the sample used was drawn from clients seen in only one private practice and that only 42% of the questionnaires were returned.

Effect of the bacterial DNA gyrase inhibitors, novobiocin, nalidixic acid, and oxolinic acid, on oxidative phosphorylation

When incubated with isolated intact rat liver mitochondria, novobiocin and nalidixic acid act as uncouplers of oxidative phosphorylation; they stimulate oxygen uptake and inhibit ATP synthesis. Novobiocin is about as powerful an uncoupler as is 2,4-dinitrophenol, nalidixic acid is somewhat less powerful, and oxolinic acid exerts no inhibition whatsoever at the concentrations used. The three inhibitors are without effect on oxidative phosphorylation in Escherichia coli nor does novobiocin affect this process in a novobiocin-permeable mutant of yeast. While it would appear that oxolinic acid may be a relatively specific tool for the manipulation of the superhelicity of DNA in complex systems such as mammalian mitochondria and intact mammalian cells, the specificity of each of these inhibitors may depend upon the particular conditions and species used and such experiments require adequate controls on oxidative phosphorylation.

The presence of anti-HBc in a dental school patient population

Testing for three serum markers in screening for hepatitis B disclosed 34 of 292 patients testing positive to anti-HBc. Responses to the medical history alone disclosed only one patient with a history of hepatitis. Seroanalysis, plus a complete history, yields the most reliable results.

Retention of orthodontic bands with new fluoride-releasing cements

The prevalence of enamel decalcification beneath orthodontic bands has indicated the need for a fluoride-releasing, enamel-adhesive orthodontic luting cement. The purpose of this study was to compare the retentive bond strengths of orthodontic bands cemented with two new fluoride-releasing cements, a zinc polycarboxylate and a glass ionomer, with the retentive bond strength of bands cemented with the standard orthodontic cement zinc phosphate. The site of cement failure was also evaluated. One hundred eighty extracted human molar teeth were embedded in resin blocks and randomly assigned to three cement groups. Adapted bands were cemented by a clinically acceptable technique. The cemented teeth were then assigned to one of three time intervals--24 hours, 7 days, and 60 days--and thermocycled in synthetic saliva. The force required to initially fracture the cement bond was used as a measure of cement retention. By means of the Instron, a tensile load was applied to each cemented band. The maximum retentive strength (cement failure) was interpreted from the stress-strain curve at the point where linearity deviated. The failure site was judged subjectively: between cement and enamel, within the cement, or between cement and the band. Using stress at failure, an analysis of variance showed no significant differences among the retentive strengths of the three cements. The chi-square test revealed a significant difference (P less than 0.01) between failure sites of the zinc phosphate and glass ionomer cements. Significantly more bands cemented with the glass ionomer failed at the cement/band interface, leaving the cement adhered to the tooth.(ABSTRACT TRUNCATED AT 250 WORDS)

Force degradation of orthodontic elastomeric chains--a product comparison study

In the last 20 years, synthetic elastic modules have been introduced to the orthodontist. However, force decay of these materials has been a clinical problem and the purpose of this project was to evaluate the force decay patterns of three commercially available elastomeric products--Ormco Power Chain II, Rocky Mountain Energy Chain, and TP Elast-O Chain--in a simulated oral environment. Thermal-cycled samples experienced less force decay over a 21-day period than samples stored at 37 degrees C. Furthermore, statistical analysis confirmed that there was a highly significant difference (p less than 0.01) between the mean force exerted by short modules and long modules for each material. Overall, modules producing higher initial forces (short modules) underwent less force decay after 21 days than did modules producing lower initial force values (long modules). All materials exerted 216 to 459 grams of force initially. After 21 days of simulated tooth movement, the force exerted by the elastic modules was 70 to 230 grams--a significant reduction (p less than 0.001).

Effects of solution depletion on films developed in the Peri-Pro automatic processor

The changes in image quality and archival quality of dental films processed successively at room temperature in a Peri-Pro automatic processor without replenishment were measured. The changes in base-plus-fog density, film density and image contrast were measured for each of four processing solutions. All films to be developed in a solution were processed within 4 1/2 hours. The results cannot be generalized to solutions left overnight in the Peri-Pro processor or to solutions used in other automatic processors at different time-temperature cycles. If about 500 films are to be processed in a single day, the Peri-Pro solution, regular X-Omat, and RP X-Omat without part C are the solutions of choice. If about 1,000 films are to be processed in a single day, the Peri-Pro solution and RP X-Omat solution without part C are the solutions of choice. Only the Peri-Pro solution produced films (the first 600 films) of acceptable archival storage quality.

A test of the role of two oncogenes in inherited predisposition to colon cancer

Inheritance of mutationally altered oncogenes could predispose individuals to the development of specific tumors and account for familial tumor phenotypes. Using adjacent DNA sequence polymorphisms as genetic markers, we have examined two oncogenes, the Kirsten ras2, isolated from a human colon cancer cell line, and the Harvey ras1, isolated from a human bladder cancer cell line, for their role in the genetic etiology of inherited colon cancer in Gardner syndrome. Both oncogene loci have been shown to be unlinked to the Gardner syndrome locus and are, therefore, eliminated as candidates for the Gardner syndrome gene.