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Title: Cytotoxicity testing of endodontic sealers: a new method Authors: J. Camps et al Journal: Journal of Endodontics 2003; 29(9): 583-586. Reviewer: Brett Strong Purpose: To compare ISO standards versus a new technique for in vitro evaluation of cytotoxicity of root canal sealers. Methods
and Materials: - 30 sterile single rooted teeth, 10 per sample, were obturated with lateral condensation utilizing Cortisomol (zinc-oxide-eugenol based sealer), Sealapex (calcium hydroxide based sealer), or AH Plus (epoxy resin based sealer). - The apices of each root were then dipped into 1 ml of culture medium for 1, 2, and 30 days renewing the medium each day. The last medium, which remained in contact with the root apex for 24 hours was the ‘test medium’ and used to measure the cytotoxicity of the sealer against L929 mouse fibroblasts. - The cytotoxicity was defined by ISO standards as the respiratory function of L929 fibroblasts when evaluated by the MTT assay. Results: - Except for non-cytotoxic AH Plus, ANOVA showed a higher cytotoxicity of the sealers when tested with ISO standards versus the root-dipping technique. - - The root-dipping technique indicated that Cortisomol > Sealapex > AH Plus at day 1, and that only Sealapex showed a significant decrease in toxicity with time. Therefore, the cytotoxicity was Cortisomol > AH Plus > Sealapex at 2 and 30 days. - As an example, Sealapex was cytotoxic to 91%
of L929 fibroblasts at day 30 when tested analyzed with - This study demonstrated the null hypothesis that ISO standards may lead us to accept the cytotoxicity of endodontic sealers that non-cytotoxic when tested with the root-dipping technique. Discussion: The authors suggest that the
root-dipping technique more precisely demonstrates what cytotoxicity
may occur when a ‘classic’ root canal fill is seen. They argue that These experiments were created to imitate the previous set of tests seen in the literature, and in doing so failed to account for accumulated cytotoxicity of each individual sealer.
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Author: Iqbal et. al. Journal: JOE 2003;29(9):587-591 Reviewer: Jessy Tseng, D.D.S. Purpose: To compare apical transportation and loss
of working length caused by four different NiTi
rotary instrumentation sequences and describe the use of a new radiographic
technique for analyzing the efficacy of instrumentation techniques. Materials and Methods:
Group 1--ProFiles 0.06 in a
crown-down manner Group 2--ProFiles 0.06 in a
step-back manner Group 3--GT files in a crown-down
manner, followed by ProFile 0.06 in the crown-down
technique Group 4--GT files in a crown-down
manner and followed by ProFile 0.06 in a step-back
manner
Results:
Discussion: The
instrumentation sequence of ProFiles or
pre-instrumentation with GT files has no effect on degree of transportation
and loss of WL. |
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Author: Jean Camps and et. al. Journal: JOE:29(9)592, Sept., 2003 Reviewer: Vahid Atabakhsh, D.D.S. Purpose: To compare the classical dye-penetration method to the dye-extraction method. Materials and Methods: Forty teeth were prepared with ProFiles device and divided into four groups of 10 based on sealer used; Pulp Canal Sealer, Sealapex, AH Plus, and Ketac-Endo. The apical seal was evaluated on the same teeth with three methods, successively: Fluid-filtration method involves placing each root in a tube with 15 cm of hydrostatic pressure with an air bubble in the column which moves as fluids filter into the root. A computer calculates the bubble’s displacement to the nearest 5 micron with an infra-red light shining on the edge of the bubble. Dye-penetration method involves leaving the apical area of each RCT treated tooth exposed to 2% methylene blue. The teeth were allowed to dry and sectioned longitudinally with a fissure bur, exposing gutta percha at its greatest diameter through out the length of the root canal. The dye-penetration was measured in millimeters with a calibrated microscope eyepiece. Dye-extraction method used the two halves of each root obtained from the dye-penetration technique. They were stored in a vial with 600 micro liters of 65% nitric acid for 3 days. Then 200 micro liters of each vial were then transferred to a 96 well-plate and absorbance of the plate measured with a spectrophotometer with nitric acid as the blank. Results: The classical dye penetration method did not show any difference among the sealers and showed no correlation with the two other techniques. The fluid filtration (p<0.01) and the dye-extraction (p<0.01) showed that sealapex displayed the highest apical leakage. The correlation between the results obtained with these two methods was significant (p=0.001 and r=0.7). Previous studies have shown poor correlation between the dye-penetration technique and radioisotope technique, a bacterial leakage study, and the fluid filtration technique. Discussion: This study showed the limitation of the classical dye-penetration studies. It is likely that dye penetration does not progress uniformly in roots, thus its measurement relies on randomly cutting the root into two pieces without knowing if the section goes through the deepest dye penetration. Dye-extraction involves recovering all the dye that penetrated the apex, thereby avoiding the limitations of sectioning the root. Fluid-filtration gives similar results to the dye-extraction technique as it takes into account all the porosities of the root-filling material interface. In addition, both techniques involve quantitative measurements of the passage of the liquid within these interfaces. Dye-extraction is advantageous as it takes only 3 days needed for the dissolving of the root whereas the fluid-filtration method has to be done sequentially; in this experiment this took eight weeks. The advantage of the dye-penetration technique is that it is fast and easy to do and does not require sophisticated materials, but gives questionable results.
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Author: A. Gesi, et al. Journal: JOE, 29(9), 580, September 2003 Reviewer: Sang Shin, D.D.S. Purpose: To evaluate the time needed
to remove several types of fiber posts using two different bur kits.
Estimates refer to the time needed to pass the fiber post until arriving at
the gutta-percha. M&M: Sixty extracted anterior teeth were treated endodontically.
A post space with a standard depth of 10 mm was prepared in each root canal.
The sample was randomly divided into 3 groups of 20 specimens each. Three
different types of posts were cemented: Group
1, Conic 6% tapered fiber posts (Ghimas): white
fiber post Group
2, FRC Poster fiber posts (Ivoclar-Vivadent):
translucent fiber post Group
3, Composipost carbon fiber posts (RTD): first
carbon fiber post To remove the post, for
half of each group’s specimens the burs from the RTD fiber posts removal kit
were used (subgroup A). From the other half of the teeth in each group
(subgroup B), posts were removed by using a diamond bur and a Results: Composipost carbon fiber posts (group 3)
took significantly less time to remove than the other two types of posts (p
< 0.05). For the bur kits, the procedure involving the use of a diamond
and a |
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Title:
The
significance of needle deflection in success of the inferior alveolar nerve
block in patients with irreversible pulpitis Author: Kennedy et al. Journal: Journal of Endodontics Vol. 29, No. 10, October 2003 Reviewer: Sahrip Kim, D.D.S. Purpose:
Materials
and Methods: -64 symptomatic patients with irreversible pulpitis of a mandibular posterior tooth randomly received 2.8 ml of 2% lidocaine with 1:100k epi using either a conventional IAN block or a bi-directional needle rotational technique using the Wand II injection system. -The conventional IAN block was administered with the needle bevel oriented away from the mandibular ramus so the needle would deflect inward toward the mandibular foramen. -The bi-directional needle rotation technique was administered by rotating the Wand handpiece assembly in a clockwise-counterclockwise movement to minimize needle deflection -Endodontic access was begun 17 min after solution deposition, and all patients were required to have profound lip numbness -Success was defined as none or mild pain (VAS recordings) on endodontic access or initial instrumentation Results: -Conventional method: 50% success rate -The bi-directional needle rotation technique: 56% success rate. Discussion:
-No significant difference between success rates of the two techniques -Neither technique resulted in an acceptable rate of anesthetic success in patients with irreversible pulpitis. |
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Title: Calcium hydroxide as an intracanal medication: effect on post-treatment pain Author: Walton, E., et al. Journal: JOE 29(10), Oct. 2003, 627-29. Reviewer:
Aaron Doms Purpose: To study whether calcium hydroxide had a pain-controlling effect at different times when compared with no intracanal medication. Methods & Materials: 140 patients receiving RCT were divided into two test groups: one received intracanal calcium hydroxide; the other had only a cotton pellet placed in the chamber. 31% of patients had vital pulps and 69% had necrotic pulps and were divided equally among the two groups. Approximately half of each group had periapical pathosis. 27% of patients in the calcium hydroxide group presented with significant pain, while 33% presented with pain in the cotton pellet group. Calcium hydroxide was prepared mixing pure powder with 2.5% methylcellulose solution and made into a paste. Apical stops were prepared to at least a #25 master apical file with a step back technique using 2.5% sodium hypochlorite irrigant and final drying with paper points. Patients were instructed to record their incidence and level of discomfort, and use of analgesics. The four pain categories were as follows:
Pain ratings were recorded by patients at 4, 24, and 48 hours after treatment. Results: No significant differences were found between the calcium hydroxide and dry cotton pellet groups as far as post-treatment pain, including pain incidence and pain levels. There was a decrease in pain at each successive time period for all subjects:
Discussion: Calcium hydroxide as an intracanal medication is not useful to prevent or reduce postoperative pain, even though it has been shown to be effective against bacteria and with detoxifying lipopolysaccharides.
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Title:
Taxonomic changes of bacteria associated with endodontic
infections Author:
Siqueira J. Journal:
JOE, vol. 29(10), 619 October 2003 Reviewer: Hung Do, D.D.S. Purpose:To outline the changes in taxonomy of the
major putative endodontic pathogens that have occurred
in the past 15 years and to compile data from studies regarding the detection
of known and novel bacterial species that had never been previously reported
in endodontic infections. Discussion:
- this method allows
classification according to phylogenetic relatedness -Present methods
for bacterial taxonomy are now mainly based on nucleic acid analyses rather
than on phenotypic characteristics
-mainly gram (-) bacilli -Bacteroidesspecies now transferred to the genus Prevotella and Porphyromonas -P. gingivalis P. endodontalis
- consistently isolated/detected from endodontic
infections ·
- G(+) rods, anaerobic - Eubacterium lentum ®
Eggerthella lenta -Eubacterium alactolyticum
® Pseudoramibacter alactolyticus -Eubacterium exiguum ®
Slackia exigua
-all oral spirochetes
1.Actinobacteria 2.Fusobacteria 3.Proteobacteria 4.Bacteroidetes 5.Firmicutes 6.Spirochaetes
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Title: Long-term survival of
root-canal-treated teeth: A
retrospective study over 10 years. Author: Dammaschke, et al. Journal: JOE, 29, (10)638, Oct 2003. Reviewer:
Jonathan Lee, D.D.S. Purpose: To evaluate the success
rate of root canal treatments conducted under standardized clinical
conditions by students at M&M: 144 patients with 190 root
canal fillings fulfilling the following criteria were selected for the
study: dental record up to 10 yrs, at
least one follow up x-ray during that period, root canal treatment performed
by students. Examination
parameters: age, gender, tooth number,
number of root canals, type of coronal restoration (post + crown, cast
restoration, alloy, composite, temporary), degree of root canal filling
length (over fill, 0-1mm to the apex, 1-2mm to the apex, >2mm to the
apex), apical lesion (yes or no), date of fill, date of last follow up, date
of extraction if performed, condition of tooth (in situ or extracted). Each
root canal fillings valued as success if in
situ after final examination. Results:
Conclusion:
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