|
|
|
|
|
|
|
|
|
|
|||
|
|
Title: The effects of temperature on sodium hypochlorite short-term stability, pulp dissolution capacity, and antimicrobial efficacy Author: Sirtes, G. and et. al. Journal: JOE, vol 31, (9), 699, September 2005 . Reviewer: Brian Barker, DDS Purpose: To study the in vitro short-term stability, pulp dissolution, and antimicrobial efficacy of preheated NaOCl solutions using a syringe heating device. Materials and
Methods: Short Term Stability · 1%, 2.62%, and 5.25% NaOCl solutions were prepared by diluting a 14% NaOCl solution. The available chlorine (OClˉ and HOCl) content of NaOCl solutions was measured using a standard iodine/thiosulfate titration method. · Four 10ml syringes were filled with NaOCl solutions and heated in a syringe warming device (Keydent) to 45˚C and 60˚C. The control was NaOCl cooled to a constant 20˚C. · Chemical stability was determined by measuring the amount of available chlorine in solutions over time using the iodine/thiosulfate titration method. Measurements were taken for solutions after 15, 30, and 60 minutes of heating. Pulp Dissolution
Capacity · Twenty-two teeth (10 third molars, 12 premolars) were extracted for malposition or orthodontic reasons and immediately frozen to preserve pulpal tissues for the tissue dissolution assay. · The teeth were then thawed, split in two pieces with a micro-chisel, and the entire pulp was excavated. Five human pulp specimens were randomly used per irrigating solution: 1% NaOCl at 20˚, 45˚, and 60˚C. A 5.25% NaOCl solution at 20˚C was used as the negative control, and two pulp specimens were irrigated with .9% saline as the positive controls. · The pulps were weighed, placed on a filtered vacuum pump, and irrigated with 5ml of test or control solutions for 60 seconds. This was followed by a 120 second rinse with distilled water to halt the dissolution, and an additional 60 seconds of vacuuming to remove excess fluid. The remaining pulp tissue was then re-weighed. Antimicrobial Efficacy ·
E. faecalis cells were cultured, washed with phosphate
buffered solution, and harvested. The
bacteria were then suspended in PBS to a cell concentration of approximately
4 x 106 colony forming units per
ml. Test solutions were: NaOCl 0.001,
0.0001, and 0.00001% (wt/vol); control solutions
were 0.1M sodium thiosulfate, 0.1M sodium thiosulfate + 0.001% NaOCl, and
PBS. ·
Solutions were either heated to 45˚ or
cooled to 20˚C, and ten microliters of
bacterial solution was added to 890 microliters of
these solutions, and incubated for 10 minutes at the respective temperatures. ·
100 microliters of a
0.1M sodium thiosulfate solution was added to halt NaOCl antimicrobial activity. This solution was then diluted, cultured,
and colonies were counted. Results: ·
NaOCl solutions of
1, 2.62, and 5.25% kept 100% of their available chlorine at 20, 45, and 60˚C
during the entire 60 minute period. ·
Significant differences (p<0.05) were
recorded in percent dissolved tissue with 1% NaOCl
60˚>45˚>20˚C solutions.
In addition to this, a 1% NaOCl 45˚C
solution was equally effective as the negative control (5.25% NaOCl at 20˚), and a 1% NaOCl
60˚C solution was significantly more effective than the negative control
(p<0.05). ·
The pure 0.001% and 0.0001% NaOCl solutions had twice as much antimicrobial activity
at 45˚C over the 20˚C solution.
0.00001% NaOCl solution was ineffective at
both temperatures. Discussion: These results indicate that preheated NaOCl remains stable at clinically relevant periods of time, improves pulp tissue dissolution, and can increase the efficacy at eliminating stationary phase E. faecalis. This is significant because lower concentrations of NaOCl at elevated temperatures can be used more effectively over higher concentrations of room temperature NaOCl, thereby reducing the toxic hazard of using a 5% NaOCl solution for canal irrigation. |
|
Title: Effect of white-colored mineral trioxide aggregate in different concentrations on candida albicans in vitro Journal: JOE 31(9): 684-686 Author: K. Al-Hezaimi, et al. Reviewed by: Tiffany Manzoni, DDS Purpose: Different concentrations of white-colored mineral trioxide aggregate (MTA) in various exposure periods were tested to assess the antifungal effects against C. albicans. Materials and Methods: A fresh mix of MTA was prepared in concentrations ranging from .78-50mg/ml by dilution with 10ml molten agar at 45° C. The MTA-agar compound was mixed, poured into sterile Petri dishes and allowed to set. 348 agar plates were divided into experimental groups of 11 each and control groups of 5 each. Agar plates without MTA were the positive control and agar plates without C. albicans were the negative control. Fresh inoculate of C. albicans was prepared by growing an overnight culture from stock culture obtained. Aliquots of C. albicans were taken from the stock culture and plated on the agar compound of experimental and positive control groups. All plates were then incubated at 37° C and assessed at 1, 24, 48, and 72-h time periods at which time the presence/absence of C. albicans was assessed and recorded. Results: A direct correlation between MTA concentration and its inhibition effect on C.albicans growth was noted. Plates containing a 50mg/ml concentration of MTA did not show growth in any of the time periods tested. Plates containing a 25mg/ml concentration of MTA showed fungal growth only at 48 and 72 hours. Plates containing lower concentrations of MTA all showed fungal growth in all time periods tested. The negative and positive controls showed no fungal growth. Discussion: MTA may assist in enhanced tissue healing and management of fungal growth in cases of persistent and secondary infection. White-colored MTA in concentration of 50mg/ml exerts an antifungal effect against C. albicans for up to 3 days. Lower concentrations may not be effective. |
|
Title: In vitro evaluation of the antibacterial efficacy of chlorine dioxide on e. faecalis in bovine incisors. Author: Eddy, R.S. et. al. Journal: JOE, vol 31, ( 9), 672, September 2005. Reviewer: Derek Chu, DDS Purpose: The purpose of this study is to evaluate the antibacterial efficacy of chlorine dioxide as an endodontic irrigant. Methods and Materials: Thirty-seven bovine central incisors were extracted, and the root portions were sectioned with diamond saw and water coolant to create discs which were 5mm in height. A total of 60 disks were sectioned. The lumens were then standardized to 2.5mm with an ISO 025 round bur. Smear layer removed by immersing specimens in ultrasonic bath first with 17% EDTA for 4min, then 5.25% NaOCl for 4min. The discs were then placed in distilled water and sterilized in steam autoclave. The discs were mounted and the lumens were filled with 25 µl Brain Heart Infusion (BHI) broth containing 1.0x108 cfu/ml of e. faecalis and then incubated at 370C in 5% CO2 for 72 h. The discs were then flushed with sterile saline, and lumens enlarged to 2.9mm with sterile slow speed ISO 029, to simulate endodontic instrumentation. Sixty prepared discs were randomly divided into four experimental groups and filled with one of the following irrigants for 30min: Group 1: 10% Clidos-S Group 2: 13.8% BioClenz Group 3: 5.25% Chlorox Group 4: Saline After 30min, the samples were pulverized with liquid nitrogen, and transferred to sterile vials containing 2ml PBS (Phosphate Buffered Saline), vortexed, followed by serial dilutions. Aliquots of each dilution from each group was plated on BHI plates, incubated, counted, and compared. Results/Conclusion: Chlorine dioxide and NaOCl were both effective in eliminating e. faecalis from the dentinal disks within 30min. Bacterial counts: Saline > Clidox-S = BioClenz > Clorox. Using saline as baseline, 5.25% sodium hypochlorite eradicated 99.98% of e. faecalis while 10% Clidox-S and 13.8% BioClenz eliminated 84% and 92% respectively.
|
|
Title: Homogeneity and adaptation of a new gutta-percha paste to root canal walls Author: ElAyouti, A, et al Journal: JOE, 31, (9) 687-690 Reviewer: Marcus L. Palermo, DDS Purpose: To evaluate the adaptation of GuttaFlow® (GF) to root canal walls compared to cold lateral condensation and thermoplasticized gutta-percha techniques as well as detect voids. Methods and Materials: Ninety extracted human teeth (molars, premolars and anteriors) w/ intact or restored crowns were selected. A total of 169 root canals were treated in mounted maxillary or mandibular models in a mannequin head. Teeth were treated w/ 6% taper rotary Hero instruments sizes #30, 25 and 20. Apical preparation was made with LightSpeed instruments to 1mm short of apical foramen. Teeth were filled with GuttaFlow®, Lateral Condensation or Vertical Condensation (VC). All teeth were sectioned at 5 levels based on root length. 1690 sections were viewed w/ x20 stereoscope. Recordings were made for: 1) area of voids (AV) 2) Number of sections w/ voids 3) location of voids (in core or along root canal walls) Results:
The section with the highest number of voids came from the junction of the middle and apical thirds. Conclusions: The GuttaFlow® group showed the lowest percentage of area of voids, but the highest number of sections w/ voids, which is explained by the small size of the individual voids. Nearly all voids in the GF group were enclosed in the core of the filling material and root canal wall adaptation was almost complete. The VC group had the highest percentage of AV, which is likely due to the preparation technique. The highest incidence of voids was found in the section taken from the junction of the middle and apical thirds, which is likely due to the complex anatomy found at this level of the root. While the GuttaFlow® teeth showed small voids, it may be a promising material to use due to its good adaptability to root canal walls and ease of placement. Further studies relating to leakage and overfilling when using GuttaFlow® need to be addressed. |
|
|
Title: Levels of evidence for the outcome of nonsurgical endodontic treatment Author: Torabinejad et al Journal: JOE , vol 31, (9), Sept 2005 Reviewer: Alex Wang, DDS Purpose:
Materials &
Methods:
Results: 306 clinical studies were identified
and they include: 6 RCT (LOE1), 12 low quality RCT (LOE2), 14 cohort studies (LOE2), 5 case control and 8 cross sectional studies (LOE3), 4 low quality cohort studies (LOE4), and 5 low quality case-control studies (LOE4). - The majority (73) of the often quoted “success and failure” studies were LOE 4 Conclusion: Few high-level studies have been published related to the success and failure of nonsurgical RCT |
|
Title: The effect of human immunodeficiency virus on endodontic treatment outcome Author: Quesnell et al. Journal: JOE, Vol. 31, (9), pg. 633-6, September 2005 Reviewer: Bryan Stein, DMD Purpose: To
compare periradicular healing between 1 year after endodontic treatment of necrotic teeth with chronic
apical periodontitis (AP). Materials &
Methods:
Results:
Discussion: Clinicians need not alter expectations
for healing and resolution of periradicular lesions
based on the HIV status of their patient |
|
Title: Properties of a new root-end filling
material Author: Chng, H.K. et.
al. Journal: JOE, 31, (9), 665, September 2005 Reviewer: David Tran, DMD Purpose: To study the physical properties and
root-end sealing ability of Viscosity Enhanced Root Repair Material (VERRM)
and to compare them with ProRoot MTA (GMTA) and ProRoot MTA (Tooth Colored Formula)(WMTA). Materials and Methods: pH ·
Samples of
VERRM, GMTA, and WMTA were freshly mixed and pH readings were taken at 2 min.
intervals for 60 min. at a temperature of 24° C. Setting Times, Solubility, Radiopacity, Dimensional Change ·
The method
described by the International Organization of Standardization for dental
root canal sealing material (ISO 6876:2001) was used to determine solubility,
radiopacity, and dimensional change following
setting of VERRM, GMTA, and WMTA. ·
The method
described in ASTM C266-03 was used to determine setting time. Apical Sealing Ability ·
The crowns of
22 single-rooted human premolars were removed at the CEJ. The root canal was prepared using step back
technique with K-type files and 5.25% sodium hypochlorite as irrigant and obturated with
gutta-percha and Roth Root Canal Cement Type 801 sealer using lateral
condensation. ·
Apical root
resections were performed by removing 3mm of the apex and then preparing a
3mm deep root-end cavity using a round bur and slow speed handpiece. The teeth were coated with two layers of
nail varnish except at the tip. The
teeth were retrofilled and divided into Group 1 – VERRM Group 2 - GMTA Group 3 - WMTA.
·
Two teeth with
retro-preparation but no retrofilling were positive
controls and two teeth without root-end resection and completely covered with
nail varnish served as negative controls. ·
All teeth were
stored at 37° C and 95% humidity for 24 hrs and then in non-buffered 1% methylene blue solution for 72 hrs. Specimens were sectioned and examined under
a stereo-microscope to determine depth of dye penetration. Results: ·
No significant
difference in the pH between the three materials when freshly mixed and at 30
min. No significant difference in the
pH of VERRM and GMTA at 60 min.
However, WMTA had significantly higher pH than both VERRM and GMTA at
60 min. ·
The initial
setting times were significantly different for the three materials. The final setting time of GMTA was
significantly higher than VERRM and WMTA. ·
The solubility
of VERRM is significantly higher than GMTA and WMTA. ·
No significant
difference in dimensional change among the three materials. ·
The radiopacity of VERRM was slightly lower than GMTA and
WMTA. ·
VERRM and WMTA
showed significantly greater dye penetration than GMTA. There was no significant difference in
depth of dye penetration between VERRM and WMTA. Discussion: The results show that VERRM has similar physical
properties and sealing ability to WMTA and may be suitable for clinical
use. A subsequent article will review
the viscosity, working time, and specific working characteristics of
VERRM. Further studies are also needed
to assess the biocompatibility of VERRM. |
|
Title: Effectiveness of resin-coated gutta-percha cones and a dual-cured, hydrophilic methacrylate resin-based sealer in obturating root canals. Author:
Franklin R, Journal: Journal of Endodontics Volume 31, Number 9, September 2005 Reviewed by: Ryan Savage, DDS Introduction: There is an increasing interest in methacrylate resin-based sealers in endodontics, as they may be used with dentin adhesives for bonding to intraradicular dentin. This bonding concept is hampered by the lack of a chemical union between the poly-isoprene component of gutta-percha and the methacrylate-based resins. A recent strategy to overcome this problem has led to the development of a unique resin-coating of conventional gutta-percha with two important functional groups-one group with binding affinity for the polyisoprene component of gutta-percha and the other with a binding affinity for methacrylate based resin sealers such as EndoRez. Purpose: To
study the effectiveness of resin-coated gutta-percha and the methacrylate resin-based sealer EndoRez
in obturating root canals through the use of
stereomicroscopy, environmental, or conventional scanning electron microscopy
( Methods and Materials: 24 single-rooted human premolars were accessed using an operating microscope. Patency was confirmed with a size #15 Flex-o-file. WL was established within 1mm of the apex. Instrumentation using a crown-down technique, with 0.06 taper NiTi rotary instruments to ISO size #25. Canals were rinsed alternatively with 17% EDTA and 2.6% NaOCL, with EDTA used as the final rinse to minimize the residual effect of NaOCl on free-radical polymerization. A 0.06 taper resin-coated master gutta-percha cone was fitted and trimmed 0.5mm short of WL. Canals were dried with paper points and a dual-cured form of EndoRez was injected into the root canals with a 30-guage NaviTip that was inserted 2 to 3mm short of WL. The prefit master cone was inserted followed by passive placement of multiple accessory 0.02 taper resin-coated gutta-percha cones. Radiographs were used to confirm adequacy of obturation, coronal segment of sealer was light-cured and excess gutta-percha seared with a hot instrument. A self-etching adhesive/primer and flowable composite were placed over the canal orifice to act as a secondary seal. Tracer Penetration: 20 teeth were sectioned to produce a standardized 10mm root segment. Segments were coated with nail polish except in the apical 2mm and 2mm circumferentially around the canal orifice. Segments were immersed in 50 wt% ammoniacal silver nitrate at a pressure of 30kPa for 3 hours. They were then rinsed and placed in photo developer to reduce silver ions into metallic silver. Roots were then sectioned and examined for leakage under a 30X stereomicroscope. TEM Examination: The previously examined silver-impregnated sections were prepared for TEM examination by direct sectioning through the gutta-percha. |
|
|
|||||
|
|
|
||||
|
|