James P. Scheetz

Linear accuracy and reliability of cone beam CT derived 3-dimensional images constructed using an orthodontic volumetric rendering program.

OBJECTIVE To compare accuracy of linear measurements made on cone beam computed tomographic (CBCT) derived 3-dimensional (3D) surface rendered volumetric images to direct measurements made on human skulls. MATERIALS AND METHODS Twenty orthodontic linear measurements between anatomical landmarks on 23 human skulls were measured by observers using a digital caliper. The skulls were imaged with CBCT and Dolphin 3D (version 2.3) software used to generate 3D volumetric reconstructions (3DCBCT). The linear measurements between landmarks were computed by a single observer three times and compared to anatomic dimensions using Students t-test (P < or = .05). The intraclass correlation coefficient (ICC) and absolute linear and percentage error were calculated. RESULTS The ICC for 3DCBCT (0.975 +/- 0.016) was significantly less than for skull (0.996 +/- 0.007) measurements. Mean percentage measurement error for 3DCBCT (2.31% +/- 2.11%) was significantly higher than replicate skull measurements (0.63% +/- 0.51%). Statistical differences between 3DCBCT means and true dimensions were found for all of the midsagittal measurements except Na-A and six of the 12 bilateral measurements. The mean percentage difference between the mean skull and 3D-based linear measurements was -1.13% (SD +/- 1.47%). Ninety percent of mean differences were less than 2 mm, and 95% confidence intervals were all less than 2 mm except for Ba-ANS (3.32 mm) and Pog-Go(left) (2.42 mm). CONCLUSIONS While many linear measurements between cephalometric landmarks on 3D volumetric surface renderings obtained using Dolphin 3D software generated from CBCT datasets may be statistically significantly different from anatomic dimensions, most can be considered to be sufficiently clinically accurate for craniofacial analyses.

Linear accuracy of cone beam CT derived 3D images.

OBJECTIVE To compare the in vitro reliability and accuracy of linear measurements between cephalometric landmarks on cone beam computed tomography (CBCT) 3D volumetric images with varying basis projection images to direct measurements on human skulls. MATERIALS AND METHODS Sixteen linear dimensions between 24 anatomic sites marked on 19 human skulls were directly measured. The skulls were imaged with CBCT (i-CAT, Imaging Sciences International, Hatfield, Pa) at three settings: (a) 153 projections, (b) 306 projections, and (c) 612 projections. The mean absolute error and modality mean (+/- SD) of linear measurements between landmarks on volumetric renderings were compared to the anatomic truth using repeated measures general linear model (P < or = .05). RESULTS No difference in mean absolute error between the scan settings was found for almost all measurements. The average skull absolute error between marked reference points was less than the distances between unmarked reference sites. CBCT resulted in lower measurements for nine dimensions (mean difference range: 3.1 mm +/- 0.12 mm to 0.56 mm +/- 0.07 mm) and a greater measurement for one dimension (mean difference 3.3 mm +/- 0.12 mm). No differences were detected between CBCT scan sequences. CONCLUSIONS CBCT measurements were consistent between scan sequences and for direct measurements between marked reference points. Reducing the number of projections for 3D reconstruction did not lead to reduced dimensional accuracy and potentially provides reduced patient radiation exposure. Because the fiducial landmarks on the skulls were not radio-opaque, the inaccuracies found in measurement could be due to the methods applied rather than to innate inaccuracies in the CBCT scan reconstructions or 3D software employed.

Effectiveness of Three Endodontic Irrigants at Various Tubular Depths in Human Dentin

Bacteria from infected root canals can invade dentinal tubules, thus dentin disinfection is an important aspect of endodontic therapy. This study compares three endodontic irrigants for efficiency in killing bacteria established within human dentinal tubules. Root canals in extracted teeth were prepared and sterilized. Broth cultures of Enterococcus faecalis were allowed to grow within the canals to penetrate dentinal tubules. The infected canals were exposed individually to each of the irrigants for 1 min. Irrigants were 0.525% sodium hypochlorite, Tubulicid (0.2% EDTA), and 0.12% chlorhexidine (Peridex). Sterile water was the control. Viable bacteria were analyzed by drilling incrementally into dentin from the cementum toward the canal. Smaller diameter drills were used for each depth. Shavings were cultured at three depths, for each of three root levels: coronal, midroot, and apical. Although considerable variation occurred between roots, sodium hypochlorite seemed to be superior. Tubulicid and Peridex were better than water. More bacteria remained viable at greater distances from the pulp. These observations apparently apply to all levels in the canal.

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.

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.

A laboratory study of changes in vertical dimension using a compression molding and a pour resin technique.

A controlled investigation was conducted to compare the increase in vertical dimension of complete dentures after processing with a compression molding technique and with a pour resin technique. The smallest increase in vertical dimension of occlusion was obtained with the compression molding technique.

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.

Success rate of immediate implants placed and restored by novice operators.

Aims:The primary aim of this study was to evaluate the 1-year crestal bone loss and success rate of an immediately placed single-stage implant placed and restored by novice operators. A secondary aim was to determine the patients assessment of the appearance of the final restoration. Methods:Fifty-one patients received a tooth extraction and placement of at least 1 immediate implant by a Graduate Periodontics resident. Clinical and radiographic measurements were taken at the surgical, 4-month, and 1-year follow-up visits. After at least 3 months healing, dental students restored the implants with either a crown or an overdenture. Patient satisfaction was assessed using 5 categories: excellent, very good, good, fair, or poor. Results:Sixty-two immediate implants were placed. The success rate was 100% at the 12-month visit and was subclassified as grade 3 because of the mean first year bone loss of 1.3 ± 1.0 mm. Using the 2008 classification of Misch et al, 42 implants were classified as success optimum health, 19 as survival satisfactory health, and 1 as survival compromised health. Radiographic bone loss was stratified by implant platform position relative to the alveolar crest and changed from time 0 to time 12 by −1.0 ± 1.2 mm for the supracrestal group (n = 25, P < 0.05), −1.5 ± 0.9 mm for the crestal group (n = 31, P < 0.05), and −1.3 ± 1.2 mm for the subcrestal group (n = 6, P < 0.05). The supracrestal group had significantly less bone loss than either the crestal or the subcrestal group (P < 0.05). The appearance of the final restoration at 1 year was rated excellent by 82% of patients, very good by 16%, and good by 2%. Conclusions:Immediate implant placement by novice operators using routine dental school procedures was a highly predictable procedure as indicated by the 100% success rate at 12 months. Most patients rated the restoration appearance as excellent.

Perceived quality of radiographic images after rapid processing of D- and F-speed direct-exposure intraoral x-ray films

OBJECTIVE We sought to compare the densitometric properties and perceived image quality of InSight (F-speed) and Ultra-Speed (D-speed) film radiographs processed with rapid chemistry. The effects of density, contrast, and film speed on perceived image quality were also studied. STUDY DESIGN Images were made of a human cadaver phantom with exposures to achieve background densities approximating 1.5, 2.0, and 3.0. Films were processed in a radiographic darkroom by using Insta-Neg and Insta-Fix rapid chemistry as the manufacturer had recommended. Five endodontic residents independently analyzed images of varying density, speed, and contrast that were presented in a randomized manner. They were required to evaluate the perceived image quality of 5 specifically designated areas on the film, using a labeled photograph as a guide. These areas included root canal obturation, periodontal ligament space, dentinoenamel junction, and crestal bone height. In addition, they were also asked to assess the overall perceived image quality. Statistical analysis consisted of ordinal regression and 2-factor analysis of variance. RESULTS No statistically significant differences were proved between F- and D-speed radiographs within the same density group. Higher density and higher contrast resulted in a statistically significant positive impact (P <.01) on the ranking for all 5 subjective determinations. Observers preferred the films exposed to a background density of 3.0 over those of a lower density (P <.01). CONCLUSIONS InSight (F-speed film) can be used with rapid chemistry to ensure less radiation exposure to patients than is necessary with D-speed film. The observers participating in this study preferred radiographs from the 3.0 background density group to those from the 2.0 and 1.5 density groups.

Measurement of Intraosseous Pressures Generated by the Wand, High-Pressure Periodontal Ligament Syringe, and the Stabident System

Intraosseous pressure generated by the use of three anesthetic systems-the Wand; a hand-operated high-pressure periodontal ligament (PDL) syringe; and the Stabident system-were studied in fresh mandibles of 14 large swine. The mandibles were drilled and tapped in one area of both the right and left posterior molar regions. Pressure gauges were attached via threaded fittings. Pressures during injection were recorded for the Wand first, then the PDL syringe, and finally Stabident. Results showed averages of 8.3 mm Hg generated by the Wand, 16.3 mm Hg with the high-pressure PDL syringe, and 43.7 mm Hg from the Stabident system. Results were corroborated with data from three human cadaver mandibles.