Biomedical subjects

Paul D Eleazer

Publications and source records attributed to Paul D Eleazer.

13 recordsLinked to original sources

PubMed2005

Analysis of heat generation using ultrasonic vibration for post removal.

This study measured the temperature of the root surface and post during the application of ultrasonic vibration to cemented posts to simulate post removal procedure. Root canal therapy was performed on ten extracted maxillary incisors. A stainless steel Parapost was cemented into each prepared post space. Ultrasonic vibration was applied to the post and temperatures were recorded at the coronal post and the cervical root surface. Data were analyzed with ANOVA using the independent variables of (a) time of ultrasonic application (15, 30, 45 and 60 s) and 2) location (post and root surface). Greater temperature increase was observed at the post (52.6 degrees C, SD 11.1; 82.6 degrees C, SD 20.1; 111.0 degrees C, SD 29.1; 125.3 degrees C, SD 33.2) compared to the root surface (9.5 degrees C, SD 4.6; 17.5 degrees C, SD 4.8; 25.4 degrees C, SD 7.3; 32.2 degrees C, SD 8.1) for each time period, P < 0.001. Ultrasonic application to the post for longer than 15 s generates high temperature on the root surface.

Analysis of Variance↗

PubMed2005

A comparison of torque required to fracture rotary files with tips bound in simulated curved canal.

The purpose of this study was to compare torque force and rotation needed to fracture three types of nickel titanium alloy rotary instruments in a simulated curved root canal space that were bound at the file tip. Files of similar size tips were studied. The files studied were ProFiles with 0.04 taper diameters of 15, 20, 25, 30, 35, 40, 45; 0.04 ProFile GT sizes 20, 30, 40; and ProTaper files sizes S1, S2, F1, F2, and F3. All files were 25 mm in length. Unwinding was defined as the rotation in degrees it took for a file to fracture after the first evidence of permanent deformation. All files exhibited permanent deformation before breaking, with the ProFile GT files demonstrating the greatest unwinding. The #45 0.04 ProFile withstood the most force while the #20 ProFile GT required the least amount of force before beginning to exhibit permanent deformation. The S1 and S2 ProTaper files fractured with so little rotation that no extended data were recorded. Generally, as the file diameter increased, the force needed to begin unwinding also increased. Also, as the file diameter increased, the force needed to fracture also increased.

Analysis of Variance↗

PubMed2004

A comparison of survival of teeth following endodontic treatment performed by general dentists or by specialists.

OBJECTIVE: A chart review was performed at 3 private general practices in different regions of Alabama to compare success of endodontic treatment provided by specialists versus generalists. STUDY DESIGN: To qualify for the study the general dentists had to perform some endodontic treatment and to refer some to endodontists. Success was defined as the treated tooth being present at 5 years after the date of treatment initiation. This criterion, was chosen because of its unequivocal categorization of results. Calibrated dentists reviewed over 3,000 charts. RESULTS: 350 met the inclusion criteria. 195 teeth were treated by generalists, with an 89.7% success rate. 155 teeth were treated by endodontists, with a 98.1% success rate. CONCLUSION: In this limited survey, endodontic treatment by specialists was significantly more successful.

Dental Restoration Failure↗

PubMed2004

Effect of a separated instrument on bacterial penetration of obturated root canals.

The aim of this study was to determine the effect a separated instrument has on the time required for bacterial penetration of obturated root canals. Twenty-six extracted human mandibular premolars with single canals were used in the study. Group 1 consisted of teeth that contained a separated size 40 Profile rotary file and were obturated with gutta-percha and zinc oxide eugenol sealer to the level of the separated file. Group 2 consisted of teeth that were similarly obturated, but without a separated file. The negative control canals were obturated and had the entire root surface sealed with nail polish. The positive controls were obturated without sealer. Streptococcus sanguis was placed in the access chamber daily, and penetration was determined when turbidity was noted in the culture broth. The results showed no significant difference between the two experimental groups.

Bicuspid↗

PubMed2004

pH required to kill Enterococcus faecalis in vitro.

Enterococcus faecalis tolerates highly alkaline environments, yet the exact pH required for killing E. faecalis is not known. This study tests growth at 0.5 increments from pH 9.5 to 12. Twelve culture tubes were used in each group. Positive growth was measured using turbidity, a visual scale, and a spectrophotometer. At 24 h, growth was observed in all tubes at pH 9.5 and 10. At 48 h, all pH 10.5 tubes showed growth. At 72 h, six of the pH 11 tubes showed growth. After 7 days, five of the remaining pH 11 tubes were positive. No growth occurred in any of the pH 11.5 or pH 12 tubes. Apparently, pH 10.5 to 11.0 retards growth of E. faecalis, whereas no tubes showed growth at pH 11.5 or greater.

Enterococcus faecalis↗

PubMed2003

Endodontic measurement accuracy and perceived radiograph quality: effects of film speed and density.

OBJECTIVES: This study sought to determine the effects of direct exposure x-ray film speed and background density on observer assessment of endodontic working lengths and on perceived radiographic image quality. STUDY DESIGN: A human cadaver maxilla section with surrounding soft tissues was used for the study. The canal length to the radiographic apex was determined on 4 canals in maxillary posterior teeth by using Trophy RVG images and adjusting the position of a No. 15 file in each canal until the file tip coincided with the radiographic apex in images made at 3 different vertical angulations. The files were measured with a micrometer from the file stop to the file tip to obtain the length to the radiographic apex. Then No. 10 files were placed in the 4 canals at varying lengths short of this previously determined length, and 5 observers assessed the distance from the file tip to the radiographic apex on radiographs made with Kodak D-, E-, and F-speed and Flow D- and E-speed direct exposure x-ray films that were exposed to produce background densities of 1.5, 2.0, and 3.0. Subjective appraisal of radiographic quality was also assessed. RESULTS: Analysis of variance and Tukey honestly significantly different post-hoc analysis results concerning measurement errors made with each film type revealed significantly less error for Kodak Ektaspeed Plus (E-speed) intraoral x-ray film than for Kodak InSight (F-speed) and Flow E; however, no difference was detected among Kodak Ektaspeed Plus (E-speed), Kodak Ultra-Speed (D-speed), and Flow D. Films with a background optical density of 3.0 received 98% favorable ratings; radiographs with a background optical density of 2.0 received 77% favorable ratings; and those with background optical density of 1.5 received only 18% favorable ratings at the 95% confidence level. Flow D film received the most favorable ratings, but there was no statistically significant difference among other film types at the 95% confidence level. CONCLUSIONS: Underexposed radiographs are perceived as inferior to slightly overexposed radiographs for endodontic file length assessment regardless of the film speed used. Current Flow and Kodak E-speed and F-speed radiographs appear to be as accurate as other accepted radiographs used in determining endodontic working lengths. Image background density should be kept constant when making comparisons among x-ray films.

Absorptiometry, Photon↗

PubMed2003

Tuned-aperture computed tomography versus parallax analog and digital radiographic images in detecting second mesiobuccal canals in maxillary first molars.

OBJECTIVE: We sought to evaluate the detectability of second mesiobuccal (MB2) canals in the MB root of maxillary first molar teeth by comparing (1) parallax with pairs of conventional direct-exposure film intraoral radiographs (both D-speed and F-speed), (2) parallax with pairs of charge-coupled device-based digital images acquired through the use of Trophy RVG-ui, and (3) charge-coupled device-based images acquired through the use of a Trophy RVG-ui sensor and tomosynthetically reconstructed by TACT (tuned-aperture computed tomography) Workbench Software. STUDY DESIGN: Maxillary first molars were mounted in simulated bone. Pairs of images were generated by conventional D-speed and F-speed radiography and digital radiography with a charge-coupled device-based sensor, the RVG-ui. Sequences of images were also acquired for TACT reconstruction by using the digital sensor. Observers viewed sets of images to determine the number of canals present within the MB root of each tooth. Roots were horizontally cross-sectioned and viewed under an operating microscope to determine the actual number of canals present. RESULTS: The frequency of detection of MB2 canals was remarkably similar across techniques: 39.2% to 39.6% with parallax for both types of film and for RVG-ui images, and 37.9% with TACT. No statistically significant difference was found in the detectability of MB2 canals between the modalities tested. TACT had higher correlation coefficients than the other 3 modalities with respect to intrarater and interrater reliabilities. CONCLUSIONS: (1) There was a less than 40% chance of locating MB2 canals in the MB root of maxillary first molar teeth by using parallax with pairs of digital or analog radiographs. (2) TACT did not significantly affect the rate of detection of MB2 canals.

Analysis of Variance↗

PubMed2003

A comparison of torque required to fracture three different nickel-titanium rotary instruments around curves of the same angle but of different radius when bound at the tip.

Instrument fracture is an unfortunate but possible sequela of instrumentation of canals, especially when the instrument is bound at the tip. The purpose of this study was to compare the torque required to fracture three file sizes of three different rotary file types around two simulated canal curvatures, gradual or acute, when the tip of the working end of the file was bound. Profile Series 29 0.04 and 0.06 taper and Profile 0.06 ISO rotary files were placed passively into simulated canal curvatures of the same angle but of different radii. The file tips were bound 2 mm from the working end and a measurable torque was applied until fracture. ANOVA with Tamhane post-hoc comparison showed that the 0.06 Series 29 did not differ from the ISO 0.06 taper or the 0.04 Series 29 but there was statistical difference (p < 0.01) showing that the 0.04 Series 29 broke with less force than did the 0.06 ISO files. Statistical tests (p < 0.01) also showed smaller files failed with less torque, as did files in more acute canal curvatures.

Analysis of Variance↗

PubMed2003

Objective measurement of patient's dental anxiety by galvanic skin reaction.

The purpose of this study was to determine if anxiety can be measured objectively by skin conductance of a weak electric current. Three measurements were taken. First, a standardized dental-anxiety questionnaire was given to determine anxiety. Second, galvanic skin conductance was measured. Third, polygraph responses were recorded to three key questions from the questionnaire. Questionnaire scores of these key questions were used to create two groups: anxious and not-anxious. The three key questions were subjected to polygraph verification. In the first analysis patients were excluded if the polygraph test disclosed lying on any of the three key questions. The second analysis excluded liars on a question-by-question basis. The third analysis disregarded the polygraph. A statistically significant correlation was found between skin conductance and dental anxiety in all cases. Data seem to indicate that fear of injection is the most anxiety-producing aspect of modern dentistry.

Adult↗

PubMed2002

A comparison of D-, E-, and F-speed conventional intraoral radiographic films in endodontic measurement.

OBJECTIVES: We sought to compare observer measurement error and subjective ratings for International Standards Organization D-, E-, and F-speed direct exposure dental x-ray films used to determine endodontic working lengths. METHODS: Radiographs were exposed to achieve a standard background density of approximately 2.0. Three human maxillary posterior teeth for which No. 10 K-files had been placed at various lengths within 4 canals were studied in a cadaver section. A total of 30 radiographs were used (10 from each film type). Five licensed dentists excluding all authors viewed the radiographs independently and in random sequence. Distances from the file tips to the radiographic apices were measured and were compared with known lengths for error determination. The observing dentists also subjectively rated the images as desirable or undesirable. Statistical methods included a 3-factor ANOVA with Tukey honestly significant difference post hoc analysis to compare objective measurements and chi-square with respect to subjective ratings. RESULTS: No significant differences were attributable to film speed grouping or observers (P > .05); however, there was a specimen effect in that a significant difference was found in measurement accuracy among the 4 canals (P < .05). Differences in subjective ratings for the 3 film types were not statistically significant (P > .05). CONCLUSION: All 3 film types were similar in objective and subjective ratings. This being the case, the faster film is preferred to minimize the radiation dose to the patient.

Adult↗

PubMed2002

A comparison of pain levels during pulpectomy, extractions, and restorative procedures.

Most previous studies on pain in endodontics have focused on pain that occurs after root canal therapy. Very few studies have compared pain during the root canal procedure with pain occurring during other dental procedures. In the present study, 250 patients were queried following dental procedures regarding their pain levels prior to treatment and their pain levels during the treatment procedure. Of the total number of patients, 150 had a pulpectomy, 50 patients had a single extraction, and 50 patients had a single restoration. These patients reported significantly more pain during extractions than during root canal therapy. Ninety-two percent of patients undergoing root canal therapy reported that pain during the procedure was less than or much less than anticipated. Eighty-three percent of the patients undergoing root canal therapy experienced less pain during the treatment procedure than they experienced prior to the treatment.

Adolescent↗

PubMed2002

Comparison of endodontist versus generalist regarding preference for postendodontic use of cotton pellets in pulp chamber.

A degree of uncertainty exists about the use of cotton pellets in the pulp chamber after canal obturation. The purpose of this study was to poll practicing endodontists and generalists regarding their preference. Forty-six endodontists and an equal number of general dentists were polled in a mail survey regarding their preferences for the use of a cotton pellet in the pulp chamber after canal obturation. Eighty-seven percent of the endodontists and 54% of the generalists responded. Of the endodontists, 62.5% said they thought that the general dentist wanted a cotton pellet, contrasted to 80% of the generalists. The difference in proportions was not statistically significant.

Attitude of Health Personnel↗

PubMed2002

The effect of three commonly used endodontic materials on the strength and hardness of root dentin.

The purpose of this study was to determine if calcium hydroxide, mineral trioxide aggregate, or sodium hypochlorite caused a change in the force required to fracture root dentin. Ten bovine central and lateral incisors were machined using various saws and drills to produce a cylinder of dentin with a 6.0-mm outer diameter 3.5-mm inner diameter and a length of 10 mm. The cylinders were cut lengthwise into four symmetrical pieces. The canal sides of the sections were then placed into Petri dishes containing a 1-mm depth of calcium hydroxide, mineral trioxide aggregate, sodium hypochlorite, or physiologic saline (control). The samples remained in the dishes for 5 weeks and were then shear tested by using an Instron machine. Data were analyzed using an ANOVA test for comparison of the groups as a whole, and a t test was used to compare each quarter section with its control from the same tooth. A 32% mean decrease in strength was discovered for calcium hydroxide, a 33% decrease in strength for mineral trioxide aggregate, and a 59% decrease for sodium hypochlorite. All decreases in strength were statistically significant: p < 0.001 for calcium hydroxide, p = 0.027 for mineral trioxide aggregate, and p < 0.001 for sodium hypochlorite. Results indicated that root dentin was weakened after 5 weeks of exposure to calcium hydroxide, mineral trioxide aggregate, or sodium hypochlorite.

Aluminum Compounds↗