Biomedical subjects

J L Gutmann

Publications and source records attributed to J L Gutmann.

At least 19 recordsLinked to original sources

PubMed2006

Evaluation of the accuracy of three electronic apex locators using glass tubules.

AIM: To evaluate the accuracy of three different electronic apex locators (EALs) using glass tubules. METHODOLOGY: Forty-eight glass tubules with different diameters and an agar model were used to mimic root canals. A size 15 stainless steel K-file was used as the measuring electrode. The Root ZX, Propex and Neosono Ultima EZ were used to measure the tubule length with tubules dry, or filled with 0.9% NaCl, 3% H(2)O(2), 2.5% NaOCl or 17% EDTA. The distance between the real length (RL) and measured length (ML) of the tubules was recorded. The range of RL +/- 0.5 mm and RL +/- 1 mm was used to evaluate the accuracy of the EALs. Results were subject to correlation analysis and Friedman's test. RESULTS: In dry tubules, the accuracy of Root ZX was 75-91.7% for RL +/- 0.5 mm and 100% for RL +/- 1 mm, whilst the measurements of the other two EALs were all within the RL +/- 0.5 mm. No influence from the increase in tubule diameter on the accuracy of all three EALs was observed in dry tubules. In tubules filled with electrolyte, the accuracy of the Root ZX decreased as tubule diameter increased (R(d) > 0, P < 0.05). The RL-ML distance recorded by Propex was inversely related to the tubule diameter (R(d) < 0, P < 0.05). The accuracy of Propex was 75-100% for RL +/- 0.5 mm and 100% for RL +/- 0.5 mm when the tubule diameter was not more than 0.80 mm, but decreased in tubules with diameter over 0.80 mm and filled with 2.5% NaOCl or 17% EDTA. Nearly, all the measurements (except for six tubules) using Neosono Ultima EZ were within 1 mm shorter than RL despite the contents in tubules and the increase of tubule diameter. CONCLUSIONS: The accuracy of the Root ZX decreased as the tubule diameter increased when tubules were filled with electrolytes. The electrolytes in the tubules decreased the accuracy of Propex when the tubule diameter was large. The electrolytes in tubules and tubule diameter had no influence on the accuracy of Neosono Ultima EZ. The Propex and Neosono Ultima EZ were more accurate than the Root ZX under various conditions in this laboratory study.

Chelating Agents↗

PubMed2006

Biodegradable porous calcium polyphosphate scaffolds for the three-dimensional culture of dental pulp cells.

AIM: To develop a three-dimensional culture model of human dental pulp cells (DPCs) with biodegradable porous calcium polyphosphate (CPP) scaffolds. METHODOLOGY: Human DPCs were isolated from three donors. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of CPP compared with hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP). Values were analysed using unpaired t-tests. Cells were seeded onto porous CPP scaffolds with pore sizes in the range of 200-300 microm. The nature of cellular adaptation in the three-dimensional culture model was then evaluated visually by scanning electronic microscopy (SEM) and confocal laser scanning microscopy (CLSM). The apoptotic property of cells on the scaffolds was also assessed by DNA staining with CLSM. RESULTS: The cytotoxicity assay indicated that there was no significant difference between CPP and HA for each donor's original cells (P>0.05). Calcium polyphosphate had no cytotoxic effect on DPCs, whilst SEMs showed that cells successfully adhered to CPP scaffolds and spread amongst pores. On the cell surface, fine processes and matrix secretory granules were found. Confocal laser scanning microscopy showed that cells took on a three-dimensional structure with signs of vitality. CONCLUSION: Porous CPP scaffolds are promising for the establishment of a three-dimensional culture model of DPCs.

Apoptosis↗

PubMed2004

A comparison of instrument-centering ability within the root canal for three contemporary instrumentation techniques.

AIM: To study and compare Great Taper (GT) hand files using a reversed balanced force technique, nickel-titanium (NiTi)flex files with a balanced force technique and stainless steel (SS) K-type files using a step-back technique. METHODOLOGY: Forty-eight extracted mandibular premolar teeth with single root canals having curvatures between 15 and 45 degrees were prepared using a modified Bramante model and randomly divided into three groups. The teeth were cross-sectioned at 2, 6 and 10 mm from the working length. Preoperative images of canals at three levels were captured at 20x magnification using a stereomicroscope. Canals in each group were, respectively, prepared to an apical size.10 GT file with 0.2 mm tip diameter, size 30 NiTiflex file and size 30 SS K-file. The GT file was used in a reversed balanced force technique, the NiTiflex file was used in a balanced force technique, and the SS K-file was used in a step-back technique. Postoperative canals were imaged under the conditions same as those for the preoperative canals. The postoperative images were superimposed over the preoperative images using software photoshop 6.0. The ability to maintain the instrument in the central axis of the canal and the deviation from the central canal axis were determined and compared by statistical analysis, along with the assessment of the amount of dentine removed. RESULTS: At apical level, the centering ratio, the distance of transportation and the dentine removed in GT and NiTiflex groups were significantly less than those in SS group (P < 0.01), but no statistical differences were found between the two NiTi groups. At other levels, there were no substantial differences amongst the groups. CONCLUSIONS: Compared with SS K-files, GT hand files and NiTiflex files remain better centered and produce significantly less transportation in curved canals.

Bicuspid↗

PubMed2004

A clinical radiographic retrospective assessment of the success rate of single-visit root canal treatment.

AIM: To determine retrospectively the clinical and radiographic success rate of single-visit root canal treatment performed in a busy endodontic practice using contemporary techniques of canal cleaning, shaping and obturation. SUMMARY: Seven hundred and sixty-eight single-visit cases, of which 223 presented for a re-examination appointment ranging from 6 months to 4 years from the day of treatment, were considered. Four endodontists provided examinations for both root canal treatment and re-examinations. Clinical and radiographic data were used to form an overall impression of the outcomes for each case at the time of re-examination. Available demographics and treatment information of these 223 cases were compiled for comparison. The number of treatment visits was not determined by a pretreatment diagnosis or a re-assessment of the pulp status upon entry into the tooth; therefore both vital and necrotic cases, as well as those with and without periradicular pathosis, were included. Statistical analysis was carried out using Chi-square tests and considered variations in failure rates based on gender, provider, tooth type, position and arch. A t-test was used to evaluate data on age. The overall success rate was 89.2%. No statistically significant differences were seen based on gender, age, arch or provider. Statistically, anterior teeth were more successful than posterior teeth.

Adolescent↗

PubMed2004

The efficacy of pain control following nonsurgical root canal treatment using ibuprofen or a combination of ibuprofen and acetaminophen in a randomized, double-blind, placebo-controlled study.

AIM: To compare ibuprofen, to an ibuprofen/acetaminophen combination in managing postoperative pain following root canal treatment. It is hypothesized that the drug combination will provide more postoperative pain relief than the placebo or ibuprofen alone. METHODOLOGY: Patients presenting at the Texas A&M Baylor College of Dentistry's graduate endodontic clinic, experiencing moderate to severe pain, were considered potential candidates. Fifty-seven patients were included based on established criteria. Following administration of local anaesthesia, a pulpectomy was performed. The patients were administered a single dose of either: (i) placebo; (ii) 600 mg ibuprofen; or (iii) 600 mg ibuprofen and 1000 mg of acetaminophen. Patients recorded pain intensity following treatment on a visual analogue scale and a baseline four-point category pain scale as well as pain relief every hour for the first 4 h then every 2 h thereafter for a total of 8 h. A general linear model (GLM) analysis was used to analyse the outcome. RESULTS: Based upon the GLM analysis, there was a significant difference between the ibuprofen and the combination drug group, and between placebo and combination drug groups. There was no significant difference between the placebo and the ibuprofen. CONCLUSION: The results demonstrate that the combination of ibuprofen with acetaminophen may be more effective than ibuprofen alone for the management of postoperative endodontic pain.

Acetaminophen↗

PubMed2003

Apoptosis: an introduction for the endodontist.

Apoptosis plays an important role in many aspects of endodontics, yet there is a paucity of information in this regard in the endodontic literature. Apoptosis is a single deletion of scattered cells by fragmentation into membrane-bound particles that are phagocytosed by other cells. It is a key process in the embryological development of the tooth, periodontal ligament and supporting oral tissue in the progression of oral disease, bone resorption, immunological response and inflammation, and in wound healing and certain pharmacological effects. The understanding of the ability of clinical materials to induce or inhibit apoptosis and the investigation of apoptosis as it relates to the pathogenesis of pulpal and periradicular pathology may eventually lead to new treatment approaches for the endodontist. The purpose of this review is to familiarize the clinical endodontist with current knowledge on apoptosis as it relates to the pulp and periradicular tissues.

Animals↗

PubMed2003

Osteoblasts and MG-63 osteosarcoma cells behave differently when in contact with ProRoot MTA and White MTA.

AIM: To test the hypothesis that MG-63 osteosarcoma cells and primary osteoblasts react differently to ProRoot trade mark MTA (mineral trioxide aggregate) and White MTA by: (i) investigating the attachment of primary osteoblasts and MG-63 osteosarcoma cells to ProRoot trade mark MTA and White MTA; and (ii) comparing the osteogenic behaviour of both cell lines in contact with these endodontic materials. METHODOLOGY: Primary osteoblasts were harvested from foetal rat calvaria by sequential digestion and MG-63 osteosarcoma cells were purchased. Cells were exposed to ProRoot trade mark MTA and White MTA prepared according to the manufacturer's instructions. All samples and controls were prepared in quadruplicate. After 6, 9 and 13 days exposure to MTA, the cells were fixed and prepared for SEM examination. In addition, both the cell types were grown to confluence and exposed to beta-glycerophosphate and dexamethasone to assess mineralized nodule formation as a function of osteogenic behaviour. RESULTS: The number of cells on the surface of the culture dish and on top of the materials increased in all samples throughout the 3 time periods, except for White MTA where no primary osteoblasts were visible on top of the material by the end of 13 days. After exposing cells to differentiation medium nodules were observed in cultures of primary osteoblasts, but not of MG-63 osteosarcoma cells. CONCLUSIONS: Under the conditions of this study, whilst primary osteoblasts initially bound to White MTA, they did not survive on the surface by the end of 13 days. Primary osteoblasts formed mineralized nodules when exposed to differentiation medium, whilst MG-63 cells did not form nodules. As MG-63 cells do not behave osteogenically by forming mineralized nodules, and primary osteoblasts are more sensitive than MG-63 osteosarcoma cells to White MTA in cell culture, primary osteoblasts are more appropriate than MG-63 cells for testing endodontic materials in cell culture.

Aluminum Compounds↗

PubMed2002

Comparison of Diaket and MTA when used as root-end filling materials to support regeneration of the periradicular tissues.

AIM: The objective of this study was to evaluate on a comparative basis the potential for mineral trioxide aggregate (MTA) and Diaket to promote periradicular tissue regeneration when used as surgical root-end filling materials. METHODOLOGY: Seven dogs weighing between 15 and 25 kg were anesthetized prior to having the root canals of their mandibular premolars accessed, cleaned, shaped and obturated. Coronal access cavities were restored with IRM. Surgical access to the root ends was established and the root ends were resected and prepared with ultrasonic tips. Root-end fillings of either MTA or thickly mixed Diaket were randomly assigned to the preparations. Reflected tissues were repositioned and sutured with 4-0 vicryl sutures. Sixty days postsurgery, the animals were killed, perfused with 10% neutral buffered formalin and the third and fourth premolars removed in block sections. The specimens were demineralized and sectioned at 6-microm intervals for histological assessment. Sections were stained with either haematoxylin and eosin or Gomori's one step trichrome stain and examined under the light microscope. All evaluations were made by two calibrated examiners and gradings were scored based on established criteria. The raw data was evaluated statistically using anova after adjusting for the animal block effect. RESULTS: Statistical evaluation indicated that there were no statistical differences between the observed regenerative responses of the tissues to the two root-end filling materials. CONCLUSIONS: Both Diaket and MTA can support almost complete regeneration of the periradicular periodontium when used as root-end filling materials in periradicular surgery on noninfected teeth.

Aluminum Compounds↗

PubMed2001