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Title: In vitro evaluation of the cytotoxic effect of acid solutions used as canal irrigants Author: Malheiros et al Journal: JOE, Vol 31, (10), Oct 2005 p.746-748 Reviewer: Alex Wang, DDS Purpose: To evaluate comparatively the cytotoxicity of a 17% EDTA solution and that of three different concentration solutions of citric acid (10, 15, and 25%) on cultured fibroblasts using the Trypan blue dye exclusion assay. Materials and
Methods:
Results: Short term assay (viability): 0.1% dilution: Control and treated culture maintained stable cell viability. 0.5% dilution: Cultures treated with 17% EDTA displayed large drop in cell viability, reaching total cell death within 6h. The other groups maintained cell viability. Long term assay (survival): All groups presented a continuous cell growth except for: 1. The 17% EDTA solution at a 0.5% dilution obstructed cell growth and there were no viable cells present. 2. The 25% citric acid solution at a 0.5% dilution presented a significantly smaller cell growth but did not affect the viability of cells. Conclusion: 17% EDTA caused higher cytotoxic effects than did the tested citric acid solutions. The citric acid solution did not impair cell growth and viability, proving to be non-cytotoxic in vitro. |
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Title: Periradicular status related to the quality of coronal restorations and root canal fillings in a Brazilian population. Author: Siqueira JF, et al Journal: OOOO V 100(3)369-374 Reviewer: Kevin Axx, DDS Purpose: To determine the prevalence of periradicular lesions in root-filled teeth from an urban adult Brazilian population, and to investigate the quality of root canal fillings and coronal restorations and their association with periradicular status of these teeth. Materials and
Methods: ·
2051 teeth, cross-sectional study. Examined periapical
radiographs of new patients for adequacy of root filling and coronal
restoration Endo: Adequate, Inadequate Crown:
Adequate, Inadequate, Absent ·
Outcomes were categorized Success: normal width of PDL, normal appearance of surrounding bone Failure: periradicular radiolucency Results: % Success as defined by the periapical radiograph
Not Statistically Significant Adequate endo, adequate crown vs. adequate endo, inadequate crown Statistically Significant Adequate endo, absent crown vs. adequate endo, adequate / inadequate crown All three crown categories with inadequate endo. Conclusions: This study says that the root filling is still the most important factor in periradicular health of the tissue. However, when the root filling is inadequate, the quality of the coronal restoration will then factor in to the prognosis of the tooth. There are several limitations to this study as it only considers a single PA radiograph. Some of these limitations are: a frank healing lesion, bacterial infection, and lesions entirely in cancellous bone and not visible radiographically. |
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Title: The
application of tissue engineering to regeneration of pulp and dentin in endodontics Author: Nakashima et al. Journal: JOE, vol. 31(10): 711 October 2005 Reviewer: Daniel Bitner, DMD Purpose: The purpose of this article is to review the biological principles of tissue engineering and the hurdles that must be overcome to develop regenerative endodontic procedures Tissue Engineering §
The
science of design and manufacture of new tissues to replace lost parts
because of diseases §
The
key elements of tissue engineering are stem cells, morphogens,
and a scaffold of extracellular matrix o
Stem
cells are capable of differentiating into specialized cells o
Morphogens are
biological factors that regulate stem cells to form the desirable cell type o
Scaffold
provides a biocompatible 3-dimensional structure for cell adhesion and
migration Stem Cell Therapy §
A body
of early evidence points to the therapeutic potential of adult stem cells in
preclinical studies dealing with organs such as bone, heart, liver, and
kidney Pulp Cells and Regenerative Dentinogenesis §
The
pulp is an organ known to have tremendous reparative abilities §
After
exposure of the pulp, the pulp cells and the undifferentiated mesenchymal cells that have de-differentiated from pulp
cells, endothelial cells, and pericytes, migrate to
the exposed site from the deeper region of the pulp and replace degenerated odontoblasts §
Further
progess in the scaffolds for regenerative endodontics depends on a three dimensional
microenvironment that promotes cell behavior including cell polarization and
optimal delivery of morphogens such as BMPs. §
There
are two ways to regenerate dentin o
In vivo therapy, BMP proteins or genes are applied to the exposed pulp o
Ex vivo therapy consists of isolation of stem/progenitor cells from the pulp
tissue, differentiate into odontoblasts with
recombinant BMPs or BMP genes and then
transplantation autogenously to regenerate dentin Challenges and Future
Direction § The regenerative therapy will revolutionize the future endodontics with the advances in signaling pathways underlying morphogenesis and lineage of stem/progenitor cells by morphogens and synthetic scaffolds
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Title: The influence
of preparation size on the mechanical efficacy of root canal irrigation in vitro Author: Falk, KW & Sedgley, CM. Journal: Reviewer: Brian S. Jeon, DMD Purpose: To test whether the mechanical efficacy of irrigation in the removal of intracanal bacteria is dependent on the canal preparation size. Materials and
Methods:
Results:
Discussion: § The efficacy of irrigation is significantly reduced in canals prepared to size 36 compared to size 60, but with no advantaged provided by further enlargement to size 77. § Clinicians need to balance the need for optimization of the mechanical efficacy of irrigation provided by enlargement of canals with the negative consequences of reduction and subsequent weakening of tooth structure. |
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Title: Apexification of a replanted tooth using mineral trioxide aggregate Author: Villa P. and Fernandez R. Journal: Dental Traumatology, vol. 21, no. 5, 306, October 2005 Reviewer: David Tran, DMD Purpose: To describe a case in which an apexification using mineral trioxide aggregate (MTA) was performed on an avulsed immature tooth. Case Report:
Discussion: Although the initial management of the avulsed tooth was not ideal, after 24 months there were no areas of ankylosis or inflammatory resorption. Filling the immature root with MTA (Pro Root) produced an adequate seal and allowed the formation of an apical barrier of mineralized tissue |
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Title: Replantation of 45 avulsed permanent teeth: a 1-year follow-up study Author: Chappuis V, et al Journal: Dental Traumatology 2005; 21: 289-296 Reviewer: Marcus L. Palermo, DDS Purpose: To evaluate a new treatment modality for avulsed teeth combining tetracycline, enamel matrix derivative and minimal splinting time. Methods and Materials: Forty-five avulsed and replanted teeth were followed for one year. The mean age of patients was 21 years with 74% of them under 16 years. Teeth with complex crown-root fractures, root canal-treated teeth, teeth with previous trauma or large restorations were excluded. Upon presentation, teeth were immediately placed in special storage medium for 30 min. Sockets were rinsed w/ saline. Avulsed teeth were soaked in 5% tetracycline prior to replantation. In teeth which had dry storage time >30 min EMD (emdogain) was applied into the socket and onto the root surface. Teeth with closed apices received endodontic treatment within 7-10 days. Teeth w/ open apex and ideal storage conditions were not endodontically treated. Postoperative meds included analgesics, chlorhexidine digluconate mouthwash, and all patients received systemic tetracycline regimen for 10 days. Follow-up examinations were performed at 3, 6 and 12 months. Results: The survival rate at the 1-year follow-up was 95.6% (43/45). During the one year follow-up time 80% of teeth received root canal treatment. No teeth had a vital pulp at the one year follow-up. 26 teeth (57.7%) showed normal periodontal healing at 1-year. Teeth with and open apex exhibited greater healing (62.5%) when compared to closed apices (55.2%). Replacement resorption was seen in 13 teeth and was also less frequent in teeth with open apices compared to those with closed apices. Infection-related external root resorption was always associated with pulpal necrosis. All teeth with pulp canal obliteration demonstrated periodontal healing. Replacement resorption increased w/ greater dry-storage times and was found in 100% of cases w/ dry time >60 min. Conclusions: · Tooth survival at 1 year following replantation of an avulsed tooth was 95.6%. · Replacement resorption was found in 28.9% of teeth. · Occurrence of replacement resorption positively correlated with dry storage time · Strict enforcement of endodontic treatment kept the risk of infection-related root resorption low (6.7%) · No beneficial effect of using EMD to avoid replacement resorption was found in this study This study shows some interesting results in regards to the early and strict endodontic treatment of teeth to prevent resorption, however, the short follow-up time period may be the reason for such favorable results. |
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Title: Cytotoxicity of direct current with antibacterial agents
against host cells in vitro Author: Nakamura, Y. et al Journal: JOE, vol. 31, no. 10, 755 October 2005 Reviewer: Derek Chu, DDS Purpose: To assess the biological effects and cytotoxic activity of direct current (DC) and antibacterial agents used for iontophoresis. Materials and
Methods: Iontophoresis
is a drug delivery method that uses electric current to drive water-soluble
ionized drugs and this method can deliver drugs locally at concentrations
sufficiently enough to provide therapeutic effects. The antibacterial agents
used were diamine silver fluoride sol’n (AgF), sodium fluoride,
and iodine zinc iodide solution (JJZ). PMN’s were
isolated via gradient centrifugation. The red cells were lysed
by hypotonic shock for 30sec, yielding a PMN population of > 99% viability
and > 98% purity, as judged by trypan blue dye
exclusion and cytospined staining with Diff-Quick
respectively. Cells were then resuspended in RPMI 1640 medium supplemented with 10%
heat inactivated fetal bovine serum and subjected to electric stimulus (DC 2 mA) and/or antibacterial agents for different times at 25oC. Cytotoxic
activity of DC was evaluated by MTT assay using cell counting kit. Cell death
of DC-treated PMNs were then evaluated by flow cytometry analysis with annexin
V-fluorescein isothiocyanate
(FITC) and Propidium iodide (PI) apoptosis assay
kit.
Results: Cytotoxic
effects: AgF showed the strongest cytotoxic activity, followed by JZZ and NaF. ( AgF > JJZ > NaF). In
combination with DC 2mA for 1 min, the cytotoxic
effect was significantly increased with AgF, while
only marginally with NaF and JJZ. When DC was used for 5 min, the cytotoxic effect again increased with AgF,
but NaF and JJZ reduced the cytotixicity
of DC. DC treatment (2mA, 5min)
induced necrosis rather than apoptosis for PMN. Discussion: Both DC and antibacterial agents showed
cytotoxicity in PMNs in a
time-dependent manner. Its cytotoxic effects were synergistically enhanced by AgF while not by NaF or
JJZ. In addition, DC induced necrosis
rather than apoptosis. This is
significant because necrosis will stimulate the inflammatory reaction via
necrotic PMN-derived enzymes and reactive oxygen species. Causing significantly more post operative
pain. |
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Title: Comparison of apical leakage between immediate versus delayed post space preparation using AH Plus sealer Author: F. Solano, G. Hartwell, and C. Applestein. Journal: JOE, vol. 31, no. 10, 752-754, October 2005. Reviewer: Brian Barker, DDS Purpose: This research aimed to compare the effect of immediate versus delayed post space preparation on the apical seal using AH Plus sealer. Materials and
Methods: Forty-six anterior
extracted teeth were instrumented to #30, .06 taper .5mm from the apex with
K3 files. Twenty teeth in groups 1 and
2 were obturated using warm vertical compaction and
AH Plus sealer (an epoxy-amine resin sealer).
Three teeth in groups 3 and 4 served as positive and negative
controls, respectively. In group 1 the
post space was made immediately at the time of obturation
and in group 2 the post space was made after placing the teeth in saline at
37˚C for 1 week. The post space
was made with heated instruments and gates glidden
(GG) to a depth that left 4mm of gutta percha (GP) apically. The teeth were then covered with sticky wax
and fingernail polish such that only the apical 2mm of the teeth were not
sealed. The teeth were soaked in India
ink for 72 hours, sectioned vertically, and the amount of apical dye
migration was measured. Results: Group 1 had a mean distance of .30mm dye penetration while group 2 had a mean of .93mm dye penetration. Analysis with an independent t test confirmed a significant difference (p<.05) between groups 1 and 2. Discussion: The teeth with post spaces prepared immediately after obturation had significantly less leakage when compared to those that underwent delayed post space preparation. AH Plus sealer has an eight hour setting time, and the author suggests that when the post space preparation is delayed after the setting of the sealer that the heated instruments and GG’s may introduce micro-fractures between the sealer and GP or canal wall. I would suggest that this study had a major design flaw in that group 1 teeth were never placed in saline after obturation and post space preparation, thus allowing the sealer to set in an environment free of moisture. The saline used to soak group 2 teeth immediately after obturation but before post space preparation may have altered the ability of the AH Plus sealer to properly set. |
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Title: A comparative study of three different root canal curvature measurement techniques and measuring the canal access angle in curved canals. Author: Mahir Gunday, Hesna Sazak and Yyldyz Garip Journal: Journal of Endodontics Volume 31, Number 11, November 2005 Reviewed by: Ryan Savage, DDS Purpose: To
compare and evaluate three different methods determining curvature angles
(Schneider, Weine and Long-Axis) and to introduce a
new parameter known as the “canal access angle”( Methods and
Materials: One hundred human mandibular first
and second molars were used in this study. All teeth were accessed, a size 10
K-file placed in the mesiobuccal canal extending to
the apical foramen and radiographs were taken. Long axis of the teeth was
parallel to the film, radiographs taken in a buccalingual
direction with root long axis perpendicular to the central x-ray beam.
Developed radiographs were scanned into a computer and digitized for
evaluation using the mentioned curvature techniques. Figures a-d describe the techniques employed with the various methods
to analyze canal curvature. The
authors also described and compared Results: In the first part of the study, the
mean curvature angle values measured using Schneider, Weine
and LA methods were 22.42, 29.28 and 16.79 degrees respectively. The largest
and smallest curvature angles were recorded and analyzed. ANOVA showed that there
were significant differences between the curvature angles measured using each
technique (p<0.001). Results of the second part of the investigation found
that the curvature starting distance corresponded to the coronal third in 67%
of the roots and to the medium third in the remaining 33%. The Conclusion: Most
studies of root canal curvature use the Schneider angle. The Schneider
technique mainly emphasizes canal curvature in the coronal region, the Weine technique also considers the apical region, and the
LA technique considers only the apical curvature. This study addressed two
new curvature parameters-the curvature starting distance and the curvature
height. The |
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Title: The influence of different factors on the survival of root canal fillings: a 10-year retrospective study Journal: JOE Volume 31, Number 11, November 2005: pgs 783-789 Author: R. Stoll, K. Betke, V. Stachniss Reviewed by: Tiffany Manzoni, DDS Purpose: The study evaluated the survivability of
914 root canal fillings performed in 1990 and 1991 at the Materials and Methods: A comparison was made between radiographic records taken in the respective year of treatment and radiographic records taken upon the conclusion of treatment, investigating only permanent teeth. All preparatory work was done using standard hand instruments and a step-back technique. Using the lateral condensation technique, dental students and qualified dentists filled all root canals with gutta-percha points and sealer. Data Recorded: -Date of access -Probability Index (1-2, 2-4) -Date of root canal filling -Initial filling or retreatment -Pain vs. pain-free -Operator (student or qualified dentist) -Vitality -Condensation quality -Length of Fillings -Periapical Condition Collected data was fed into the SPSS 10.0 statistics program and analyzed by the Kaplan-Meier method which calculates cumulative survivability probability (CSP) over time. Results: Survivability was determined by the continued presence of the tooth with the original root canal filling. Any intervention (ie, retreatment, extraction, root amputation, or root resection) was considered a failure. Of the records studied, there is a 0.74 overall survivability over the 10 year period studied. The factors of statistical significance that led to a higher survivability were: -Healthy baseline periapical condition -Correct length of root canal fillings -Fillings that were homogeneously condensed -Asymptomatic teeth (during treatment) -Fillings in previously vital teeth In this study, operator and retreatment had no significant statistical influence on survivability. Discussion: By proper analysis of the baseline situation, operators can initiate proper treatment options and relay realistic treatment outcomes to their patients |
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Title: Interfacial strength of Resilon™ and gutta-percha to intraradicular dentin. Author: Gesi A, et al. Journal: JOE. 2005. 31(11):809-813. Reviewer: Kevin Axx, DDS Purpose: To test the interfacial strength of Resilon™ and gutta-percha to intraradicular dentin. Materials and Methods: -20 extracted single-rooted teeth, instrumented to size 25/.06 to WL. -irrigated with 17% EDTA and 3% NaOCl, with EDTA being final rinse -divided into 2 groups; warm vertical condensation used for both Epiphany + Resilon™ used in one group AH26 + gutta-percha in the other -sliced teeth into 1mm-thick cross-sections; applied a plunger to root-filling material to introduce shear stresses at interfaces and measured when the root-filling was displaced (punched out from the section) Results: All root slices from gutta-percha group remained intact during slicing, while 6 of 33 Resilon™ fills dislodged during slicing. Interfacial failure in the Resilon™ group predominantly occurred along the surface of the intraradicular dentin (between Epiphany and dentin). For the gutta-percha group, failure was generally seen at the interface of the sealer and gutta percha. Discussion: In gutta percha-filled canals, the polyisoprene
root filling material detached from the sealer, with the latter retained on
the dentin surface. As there is no
bonding between gutta-percha, root sealer and dentin, the low interfacial
strength in this group is anticipated.
In the presence of an adhesive interface (Epiphany to dentin), the even lower interfacial strength of the Resilon™-filled root slices was unexpected. Even when premature failures (during
slicing) were excluded, the remaining Resilon™
slices demonstrated only similar strength as the gutta-percha group. Within the limits of this study, it may be
concluded that the interfacial strength achieved with Resilon™/Epiphany to intraradicular
dentin is not superior to that of gutta-percha and a conventional epoxy-resin
sealer. The results challenge the
concept of strengthening root canals with the new root filling system. |
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Title: An in vitro assessment of iodoform gutta percha Author: Chogle et al. Journal: JOE, vol. 31, no. 11, 814, November, 2005 Reviewer: Dan Bitner, DMD Purpose: To compare the abilities of medicated gutta percha containing iodoform (MGP) and standard gutta-percha points in resisting infiltration of E. faecalis using a microleakage model. Materials and Methods:
Results:
Conclusion:
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