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Endodontics
Evidence-Based Dentistry (2007) 8, 15 ,16. doi:10.1038/sj.ebd.6400467
Calcium hydroxide has limited effectiveness in eliminating
bacteria from human root canal
When patients undergo root canal treatment, does calcium hydroxide
medication eliminate residual bacteria?
Abstract
Conclusions
Based on the current best available evidence, calcium hydroxide has
limited effectiveness in eliminating bacteria from human root canals,
when assessed by culture techniques. The quest for better antibacterial
protocols and sampling techniques must continue to ensure that bacteria
can be reliably eradicated prior to obturation.
1: Dent Traumatol. 2005 Feb;21(1):42-5.
Effect of electrophoretically activated calcium hydroxide on
bacterial viability in dentinal tubules--in vitro.
Lin S,
Tsesis I,
Zukerman O,
Weiss EI,
Fuss Z.
Department of Endodontology, The Maurice and Gabriela Goldschleger School of
Dental Medicine, Tel-Aviv University, Tel Aviv, Israel.
To evaluate the ability of electrophoretically activated calcium hydroxide (CH)
to eliminate bacteria in dentinal tubules. In an in vitro model of dentinal
tubule infection, 18 cylindrical root specimens prepared from freshly extracted
bovine teeth were used. After removal of the smear layer, intracanal dentinal
tubules were infected with Enterococcus faecalis for 21 days. In 12 specimens,
CH paste was placed in the root canals for 7 days. In six of these, an
electrophoretic current (10 mA per 10 min), using two electrodes, was applied
after placing the medicament in the canal. Powder dentin samples obtained from
within the canal lumina using ISO 025, 027, 029, 031 and 033 burs were examined
for the presence of vital bacteria by inoculating agar plates and counting colony
forming units. anova with repeated measures was used to analyze results.
A significant difference was found between experimental groups and the positive
control group. CH and electrophoretically activated CH significantly (P < 0.001)
reduced bacterial viabilities in dentinal tubules to a depth of 200 microm.
Treatment with electrophoresis was significantly (P <0.001) more effective than
pure CH in depths of 200-500 microm. Specimens treated with electrophoretically
activated CH showed no viable bacteria in dentinal tubules to a depth of 500
microm from the root canal space within 7 days. The time required for treatment
of pulpal infection root resorption may be decreased, thus minimizing the risk of
coronal fractures in young patients with traumatized teeth.
1: Int J Periodontics Restorative Dent. 2008 Jun;28(3):265-71.
Efficacy of guided tissue regeneration in the management of
through-and-through lesions following surgical endodontics:a preliminary study.
Taschieri S, Del Fabbro M, Testori T, Saita M, Weinstein R.
Section of Endodontics, Department of Health Technologies,
Galeazzi Institute, University of Milano, Milan, Italy.
The purpose of this prospective study was to assess the outcome of
periradicular surgery with or without guided tissue regeneration (GTR)
for the treatment of through-and-through lesions. Thirty-four teeth were
included according to specific selection criteria. In the test group
(using GTR), after root-end filling, the defects were filled with
anorganic bovine bone and covered with a resorbable collagen membrane.
Healing was assessed according to specific criteria and graded as
successful, doubtful, or failed. In the control group, neither grafts
nor membranes were used. After 1 year, 31 teeth were evaluated. Of these,
22 (71%) healed successfully, 6 (19%) showed doubtful healing, and 2
were recorded as failures. The outcomes of the defects treated with
GTR (88% successful) were significantly better than those of the control
group (57% successful). The present study showed that the use of GTR
associated with anorganic bovine bone in the treatment of through-and
-through lesions may positively affect the healing process.
The Effect of Canal Curvature on Irrigation
Nguy D, Sedgley C. The influence of canal curvature on the mechanical
efficacy of root canal irrigation in vitro using real-time imaging of
bioluminescent bacteria. J Endod. 2006; 32(11):1077-1080.
Nguy and Sedgley quantitatively analyzed and compared the mechanical
efficacy of irrigation on bacterial debridement in curved and straight
root canals over sequential treatment procedures because of previous
lack of data on this subject. They hypothesized that efficacy of
irrigation would depend on curvature of the root canal and the canal
preparation size. They divided 33 single-rooted mandibular bicuspids
into 3 groups of 11 based on the angles of root canal curvature:
Group 1 (straight—4 to 8 degrees); Group 2 (intermediate curvature
15 to 19 degrees); and Group 3 (greatest curvature—24 to 28 degrees).
Canals were instrumented in 3 sequences: (1) size 27/.04;
(2) size 36/.04; and (3) size 46/.04. Irrigation with 5.25% sodium
hypochlorite was used during instrumentation. After each sequence of
instrumentation, suspensions of the bioluminescent reporter strain
Pseudomonas fluorescens 5RL were put into the canals, and realtime
bioluminescent imaging quantified remaining bacteria after irrigation.
In 24 to 28 degrees curvature canals prepared to size 27/.04,
irrigation was significantly less effective. The authors concluded
that instrumentation and apical enlargement of root canal systems
with increasing root canal curvatures may facilitate the efficacy of
endodontic irrigation, and consideration could be given to the
development of irrigation protocols for curved root canals.
Which of 4 Barrier Materials Prevents Microleakage
Celik EU, Yapar AG, Ates S, et al. Bacterial microleakage of barrier
materials in obturated root canals. J Endod. 2006; 32(11):1074-1076.
The use of glass ionomer cement, polycarboxylate cement, resin modified
glass ionomer cement, and flowable composite resin have been advocated
to provide a better intracoronal seal, but they have not been compared
with each other to answer questions such as the best coronal barrier
after root canal treatment, and sealing abilities. Because of this,
Celik and colleagues tested these 4 materials, comparing the bacterial
microleakage when used as a base over obturated root canals during a
5-month period. Sixty single-rooted mandibular premolars were
instrumented with a step-back technique, irrigated, dried, and obturated
with cold lateral compaction of gutta-percha. They were then divided
into 5 groups of 10 and positive and negative control groups of 5.
The pulpal floor and coronal orifice of each tooth was covered to a
depth of 2 mm with 1 of 4 restorative materials. In the fifth group,
no barrier material was placed. By using Staphylococcus epidermidis,
samples were incorporated in a model system using a microbial marker.
The seals of all experimental groups were better than the control
(the group with no barrier material). The authors concluded that within
the limitations of the study, the flowable resin composite applied
with the total-etch technique leaked significantly more than the glass
ionomer cement after a 5-month experimental period.
Surface Tension of New Irrigants with Antibiotic
Giardino L, Ambu E, Becce C, et al. Surface tension comparison of four
common root canal irrigants and two new irrigants containing antibiotic.
J Endod. 2006; 32(11):1091-1093.
Giardino and colleagues tested 2 recently introduced irrigants that
are based on a mixture of antibiotics, citric acid, and a detergent,
in response to the fact that sodium hypochlorite has shown high surface
tension and is unable to reach bacteria in the depth of the dentinal
tubules compared with other irrigants, which could be related to surface
tension created while using these irrigants. They compared the surface
tension of MTAD (Dentsply Tulsa, Tulsa, OK) and Tetraclean
(Ogna Laboratori Farmaceutici, Muggio, Italy) with the most common
endodontic irrigants: ethylenediaminetetraacetic acid (EDTA) 17%;
sodium hypochlorite 5.25%; Smear Clear, a mixture of EDTA 17% and
Tween 80 (SybronEndo, Orange, CA); and Centrexidin, a mixture of 0.2%
cetrimyde and chlorhexidine in aqueous base (GABA Vebas, San Giuliano
Milanese, Italy). Using a Cahn DCA-322 Dynamic Contact Angle Analyzer,
the surface tension of the liquids was measured after the Wilhelmy
plate technique. The force on the glass slide inserted into the test
liquid was continuously recorded by the instrument software.
All surface tensions of the test liquids were lower than those of
distilled water and sodium hypochlorite and EDTA. Tetraclean and
Cetrexidin had the lowest values. Tetraclean has lower values than
the other irrigants with antiobiotics (MTAD and SmearClear).
According to the authors, further investigation regarding the
penetration of the irrigant solutions with antibiotic into the
dentinal tubules and bacterial decontamination should be performed
to prove the capability of these new irrigants.
A Fluid Filtration Comparison of Gutta-Percha Versus Activ GP,
A New Root Canal Obturation System
G. S. Russell, P. Mines, M. J. Apicella, M. Sweet
U. S. Army Dental Activity, Fort Bragg, NC
The purpose of this study was to compare the sealing ability of gutta-percha
and AH-Plus versus the ActiV GP obturation system. The ActiV GP obturation
system was recently introduced and incorporates glass ionomer into the
gutta-percha points and is used in conjunction with ActiV GP glass ionomer sealer.
Forty eight anterior teeth were decoronated and prepared using a crown down
technique with Profile ISO series rotary files to size 50 / 0.06 taper.
The teeth were randomly divided into two groups of 20 teeth each, with the
remaining teeth serving as controls. Prior to obturation the smear layer was
removed using a 1 minute soak with 17 5 EDTA and a 10 minute soak with
5.25% NaOCL. Group 1 was obturated with glass ionomer and AH Plus sealer,
using warm vertical continuous wave of condensation technique. Group 2 was
obturated with the ActiV GP obturation sytem according to the manufacturer's
recommendations. All teeth were stored in 100% humidity at 37 degrees for
10 days allowing sealer to set before testing. Leakage was measured using a
fluid filtration method. Using Mann-Whitney U test(p< 0.05) and under the
conditions of this study there was no statistically significant difference
in leakage between Activ GP obturation system and gutta-percha and AH Plus Sealer.
J Endod. 2007 Mar;33(3):310-3. Links
Efficacy of two contemporary single-cone filling techniques in preventing
bacterial leakage.
Monticelli F,
Sadek FT,
Schuster GS,
Volkmann KR,
Looney SW,
Ferrari M,
Toledano M,
Pashley DH,
Tay FR.
Department of Restorative Dentistry and Dental Materials, University of Siena,
Siena, Italy.
This in vitro study evaluated the sealing efficacy of three root-filling
systems/techniques in preventing bacterial leakage. Instrumented single-rooted
root segments were filled with
(1) warm vertical compaction with gutta-percha/AH Plus;
(2) single-cone technique with ActiV GP; and
(3) single-cone technique with Gutta-Flow. A dual-chamber leakage model using
S. mutans as a microbial marker was used for leakage evaluation. Bacterial
penetration was monitored over a 100-day period. Leakage was recorded when
turbidity was observed in the lower chamber Gutta-percha warm vertical compaction
exhibited the best seal with bacterial leakage observed in only 16.7% of the
specimens between 59 and 100 days. All ActiV GP specimens leaked between
7 and 100 days; 50% of the Gutta-Flow specimens leaked between 22 and 100 days .
The two contemporary single-cone techniques did not insure a durable apical seal
against bacterial leakage. A warm vertical compaction technique using
thermoplasticized gutta-percha and AH Plus sealer appears to be more effective
in minimizing bacterial leakage.
Evaluation of apical surface roughness after root resection:
a scanning electron microscopic study
Marco Antonio Hungaro Duarte PhD a, , , Rubens Domingues MS a,
Marisa Akemi Matsumoto PhD a, Luis Eduardo Marques Padovan PhD a
and Milton Carlos Kuga PhD b
aBauru, Sagrado Coração University, Bauru, São Paulo, Brazil.
bFISA/FUNEC, Sagrado Coração University, Bauru, São Paulo, Brazil.
Received 3 May 2007;
Available online 18 October 2007.
Objectives
The objective of this study was to compare, by scanning electron microscopy,
the smoothness of the resected apical root surface after preparation with
high-speed #699 bur, #699 bur plus Shofu finishing and Zekrya bur, and with
an erbium:YAG laser.
Study design
Thirty-nine extracted human premolars were instrumented and obturated and their
root apices were resected. The roots were divided into 4 groups according to the
root resection method. The teeth were dried, metallized, and analyzed at ×400 by
scanning electron microscopy. Scores ranging from 0 to 3 were attributed to
surface smoothness. The data were analyzed by the Kruskal-Wallis test for overall
comparison, and by Dunn's test for individual comparisons.
Results
Smoother surfaces were observed for the groups treated with the #699 bur and the
#699 bur plus Shofu point finishing, while rougher surfaces were obtained with
the laser, which differed significantly from the other 2 methods (P < .05).
Conclusions
Treatment with the #699 bur plus Shofu finishing yielded better results in terms
of surface smoothness, whereas the laser treatment produced more irregular and
rougher surfaces after root resection.
JOE August 2003:
An in vivo comparison of two frequency-based electronic apex locators
Welk AR, Baumgartner JC, Marshall JG .
Department of Endodontology, Oregon Health & Sciences University,
School of Dentistry, Portland 97201, USA.
The purpose of this study was to compare the accuracy of a two-frequency (Root ZX)
and a five-frequency (Endo Analyzer Model 8005) electronic apex locator under
clinical conditions. Thirty-two teeth planned for extraction were used. The coronal
portion of each canal was flared using Gates Glidden drills and Orifice Shapers.
The canals were irrigated with 2.6% sodium hypochlorite. A K-type file was used
to determine a separate working length in each canal using the electronic apex
locators. The teeth were extracted and the apical 4 mm of each root canal was
exposed along the long axis of the tooth. Photographic slides of each canal were
projected and the file position in relation to the minor diameter was determined
by two investigators. The mean distance between the electronic apex locator working
length and minor diameter was 1.03 mm for the Endo Analyzer and 0.19 mm for the
Root ZX. A paired sample t test showed that the Endo Analyzer had significantly
longer readings beyond the minor diameter than the Root ZX (p < 0.0001). The
ability to locate the minor diameter (+/- 0.5 mm) was 90.7% for the Root ZX and
34.4% for the Endo Analyzer Model 8005.
An Evaluation of Root ZX and Elements Diagnostic Apex Locators.
Journal of Endodontics. 31(7):507-509, July 2005.
Tselnik, Marat DDS; Baumgartner, J Craig DDS, PhD; Marshall, J Gordon DMD
Abstract:
The purpose of this study was to compare the accuracy of the Root ZX and Elements
Diagnostic electronic apex locators under clinical conditions. Thirty-six teeth
planned for extraction were used. Each tooth was decoronated, coronally flared
with Orifice Shapers, and irrigated with 2.6% sodium hypochlorite. Working
lengths were measured with K-files using both electronic apex locators.
The files were cemented at the last measured working length and the teeth were
extracted. The apical 4-mm of each canal were exposed and photographed under
15x and 30x magnification. Images of each apex were projected and the distance
from the file tip to the minor diameter was determined. The mean distances from
the file tip to the minor diameter were 0.346 mm for the Elements Diagnostic and
0.410-mm for the Root ZX beyond the minor constriction. In locating the minor
constriction the Root ZX was accurate 75% of the time to +/-0.5 mm, 83.3% +/-0.75 mm,
and 88.9% to +/-1 mm. The Elements Diagnostic was accurate 75% of the time
to +/-0.5 mm, 88.9% to +/-0.75 mm, and 91.7% to +/-1 mm. There was no statistically
significant difference between the accuracy of the two electronic apex locators
in locating the minor diameter (p < 0.05).
4th July 2005
Wow! Best eal’s on the market only accurate less than ¾ of the time. Paper points
- looking better all the time - gary
Since this seems to NOT be the case as most of us find, could there be something
in their protocol that causes this poor results?
Even though the ZX is suppose to work in a NaOCL wet canal, I do remove much of the
excess. Could that help improve my results? I also use paper points at the last
drying to confirm - Alan Cady
I don’t think there is anything wrong with their results. Apex locators are doing
nothing more than measuring differences in electrical potential. They are the most
accurate tool we have, but they are not infallible. The point you make about
electrolytic fluids in the canals I think is a good one. This next statement is
Gary’s anecdotal finding: in my hands, none of the eal’s I have used, probably
4 or 5 different brands, seemed to give me the same accuracy as a canal that has
been instrumented to a 15 or 20, is patent, is dried, and is then measured.
In recent years, owed in part to info provided here on roots, if I have a slight
discrepancy at time of final drying with paper points, I will adjust my fill length
accordingly, and radiographically this has improved at least the visual appearance
of being at the apex on the films - gary
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