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Title: Control of microorganisms in vitro by calcium
hydroxide pastes Journal: International Endodontic Journal: 34(5): 341-345, July 2001 Author: Estrela, C. et al. Prepared by: Lance Isaac, D.M.D. Purpose: The purpose of this study was to determine the influence of vehicles on the antimicrobial action of calcium hydroxide. Materials and Methods: A total of 588, size
50, sterile absorbent paper points were immersed in various microbial
suspensions for 3 minutes. The points were then placed on Petri dishes and
covered with intracanal dressings containing
calcium hydroxide: Ca(OH)2 + saline; Ca(OH)2 +
camphorated para-monochlorophenol; Ca(OH)2
+ 1% chlorhexidine solution; Ca(OH)2 +
3% sodium lauryl sulphate;
Ca(OH)2 + Otosporin. Results: An antimicrobial effect occurred after 48h on the cultures of S. mutans, E. faecalis, S. aureus, P. aeruginosa, B. subtilis, C. albicans and a mixed culture, irrespective of the intracanal dressing. Conclusion: Under the conditions of this study, the various vehicles associated with calcium hydroxide pastes did not influence the time required for microbial inactivation.
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Author: Gambarini G. Journal: Inter. Endo. J.:34(5):386, July 2001 Reviewer: Pranav Vohra, D.M.D. Purpose: To evaluate resistance to cyclic fatigue of new and used (after 10 clinical cases) ProFile NiTi rotary instruments. Materials & Methods: 30 ProFile instruments for each of the following sizes ( .06-25, .06-20, .04-20, .04-15) were selected for study and divided into GROUP A: 10 new instruments, GROUP B: 20 used instruments.
Results: 1. In all sizes, new instruments were statistically (two sample t-test, P<.01) more resistant to fracture than used instruments. 2. No instruments, new or used, underwent intracanal failure during the test period. 3. Larger instruments failed in less time under dynamic stress than smaller instruments. 4. .04 tapered instruments were more resistant to fracture than .06 tapered instruments of the same tip diameter. Discussion: Prolonged clinical use reduces cyclic fatigue resistance of NiTi rotary instruments.
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Author: L. Bergmans Journal: International Endodontic Journal, 34(5): 390—398, 2001 Prepared by: Greg Dearing, D.M.D. Purpose: To present an objective methodology for quantitative evaluation of root canal instrumentation using microcomputer tomography, together with developed software based on a constructed mathematical model. Materials and Methods:
Results:
Conclusions:
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Week of October 8, 2001 |
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Author: J.A.P. Figueiredo, Pesce, et al. Journal: Inter. Endo. J.: 34(5): 377, July 2001 Prepared By: Alison Morrison, D.M.D. Purpose: To evaluate the creation of pigmentation and the histological response to four endodontic sealers implanted in the oral mucosal of rabbits, either by submucous injection or implantation within polyethylene tubes. Materials and Methods: Thirty white female Sealer #1 (eight rabbits) N-Rickert precipitated silver, 30.0 gms (30%) Sealer#2 (eight rabbits) AH-26, silver (10%) Sealer#3 (seven rabbits) Fillcanal Sealer#4 (seven rabbits) Sealer 26 The introduction of sealer into each rabbit was carried out in one of two ways: by submucous injection or implantation in polyethylene tubes with a small portion of cement forced out of the tube, thus simulating a common clinical situation. The location of placement (0.1mL) in each rabbit corresponds in humans to the superior gingivo-labial sulcus. Observation took place after 30, 60, and 90 days. After 90 days, the rabbits were sacrificed and the maxillae removed. Results:
Conclusion: The hypothesis that the presence of silver in the chemical composition of the sealer could tattoo the mucosal was proven. There was not only a greater number of tattoos with N-Rikert sealer, which also has a higher concentration of silver, but also, the size of these was greater than those observed with AH-26 which has a lower concentration of silver. For clinical practice, one can infer that the bigger the overflow of sealer material, the greater the risk of tattoo formation. In 1978, the silver powder in AH-26 was replaced with calcium hydroxide to form an additional sealer, Sealer-26, which is less irritating to tissues. Both sealers are used because there is still some debate about their other physical and chemical characteristics. |
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Author: M.A. Martinez-Lozano, et al. Journal: International Endodontic Journal, 34(5):371-376, July 2001 Prepared by: Donna Salin, D.M.D. Purpose: To evaluate the diagnostic efficacy of an electronic system for the determination of working length, in comparison with two radiological methods (conventional film and digital radiography). Materials and Methods:
Results:
Conclusions:
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Author: Ferraz, C., Gomes, N., Gomes, B., et al Journal: Inter. Endo J 34(5):354-358, July 2001 Key Words: apical extrusion, endodontics, engine-driven techniques, manual techniques Reviewed by: M. Pallante, D.M.D. Purpose: To evaluate the weight of debris and irrigant
volume extruded apically in vitro using
extracted teeth. Materials and Methods: In this study 5 groups of 20 extracted human teeth with single canals of similar length and shape with curvatures from 1-10° were instrumented using one of the following five techniques:
Debris extruded from the apical foramen were collected in preweighed 1.5 ml tubes. The volume of this fluid was determined using visual comparison to control tubes filled with successive .25 ml increments of distilled water. The weight of dried extruded dentin debris was also calculated. All results were analyzed statistically using the Kruskal-Wallis nonparametric test to determine is significant differences existed among the groups (P<.05) Results: No significant differences in volume of irrigant or quantity of debris existed among the engine
driven techniques. However, the balanced force technique extruded
significantly smaller amounts of irrigant and
debris than the hybrid technique. The performance f the balanced force
technique was similar to those of Ni-Ti rotary files. Discussion: Apical extrusion is important clinically when
considering that it may cause flare ups associated with the bacteria, tissue
and irrigating solutions that can be introduced into periapical
tissues. Engine driven techniques seem to extrude smaller amounts of debris
which can probably be attributed to the rotary motion which tends to direct
debris towards the orifice. Authors warn that caution should be used when
extrapolating this study to clinical situations because no attempt was made
to simulate the presence of vital pulps or periapical
tissues, both of which may restrict apical extrusion in vivo.
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Week of October 15, 2001 |
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Title: Clinical performance of three endodontic sealers Authors: Waltimo, Tuomas M.T. et al. Journal: O.O.O., July 2001 Pgs: 89-92 Reviewed by: Andy Schoelch, D.D.S. Purpose: To compare the clinical and radiographic treatment outcomes of 3 different sealers used in endodontic therapy and evaluate the effect of incorporated calcium hydroxide on the outcome of therapy. Materials and Methods: Two hundred and four teeth underwent a
standardized endodontic treatment regimen and were
assigned to 1 of three groups at the time of root filling: (1) group PS,
teeth filled with GP and Procosol sealer; (2) group
CR, teeth filled with GP and CRCS sealer; and (3) group SA, teeth filled with
GP and Sealapex sealer.
PAI index – range of 1 to 5: 1 = radiographically healthy apex 2 to 5 = increasing severity of AP Results: During the first year after filling, the mean ridit value decreased in all test groups meaning the PAI index decreased (Change in r value, SA = .20, PS = .05, CR = .03). After 2 years, teeth in group SA had slightly better PA conditions than group CR and PS. The difference was statistically significant at the P = .01 level. By years 3 and 4, no significant difference among the groups was present. Conclusion: The overall influence of the sealer on treatment outcome was small. Root fillings with salicylate resin that contain calcium hydroxide may ensure more rapid healing of apical periodontitis or operative trauma, but the results after 3 and 4 years were statistically indistinguishable from those obtained by using ZOE-based sealers with or without calcium hydroxide. |
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Author: Wallace JA, Nair MK, Colaco MF, Kapa SF Journal: Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001; 92:93-7 Reviewer: Joe Simoneaux, D.D.S. Purpose: To compare the diagnostic efficacy of conventional radiographic imaging to direct digital imaging using a charge-coupled device and a photostimulable phosphor-based sensor for detection of simulated periapical lesions. Materials & Methods: Four defleshed cadaver mandibles were invested in acrylic resin and sectioned to obtain the second premolar, first molar and second molar, separately, providing 24 samples in total. Images of the specimens were acquired before lesion induction to serve as controls. The following imaging systems were used: Ektaspeed Plus film, Soredex Digora system with PSP-based sensor and the Schick Computed Dental Radiography system with a #2 CCD-based sensor. A Gendex GX 770 x-ray source was used with constant kVp, mA and exposure time. Each image sensor was maintained in position with a precision instrument, Rinn XCP, to ensure standardized projection geometry for all systems. Lesions were produced in the apical region by using round burs #1, 2, 4 & 6. A 2-cm thick tissue-equivalent material was used to simulate attenuation and scattering of the soft tissue of the face. Images were again obtained of the samples. To ensure optimal visualization of the lesion, the digital images were subsequently enhanced through manipulation of the brightness and contrast. A panel of four observers, a periodontist, two endodontists and a general dentist, all trained in interpretation of these images, was asked to express subjective certainty of the presence or absence of a lesion using a 1-5 confidence rating scale. Each observer was allowed the option to further manipulate the image using brightness and contrast controls. The percent of correct response (PCR) was computed on the basis of imaging modality, observer and lesion size. Results: Conventional film had the highest PCR, followed by PSP and CCD-based systems. The PCR was high for all imaging modalities (film: 97%, CCD: 74%, PSP: 73%) when no lesion was present. When small lesions were present, PCR values fell more for CCD images than PSP images. No statistical difference was noted between the digital imaging modalities. Discussion: The better performance of film-based images indicates that observers were biased toward this imaging system because of familiarity and the fact that magnification can enhance resolution. On the other hand, the lack of familiarity with digital imaging and lack of experience with image enhancement resulted in poorer performance. Resolution of digital images is another factor that can affect diagnosis. It depends on the pixel size of the sensor and the resolving power of the monitor on which the images are displayed. |
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Author: E. Olutayo Delano, et al. Journal: OOO,108. July 2001 Reviewer: Mark Wang, Purpose: To compare both subjective (Periapical Index, PAI) and objective (densitometric) radiographic evaluation of healing after endodontic treatment for apical periodontitis. Material & Methods:
Results:
Conclusion:
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Title: The standardized-taper root canal preparation – Parts 1 to 6 Author: Buchanan et al. Journal: Int. End J. 2000 (33) 516-529; Int. End J. 2001 (34) 63-71,
149-156, 157-164, 244-249, and 250-259 Submitted by: Paul Slusarz, D.M.D. Purpose: This six part series introduced the concept and characteristics of variable taper instruments (Greater Taper or GT ) and illustrated the techniques used by Dr. Buchanan to instrument both large and small canals using these files. Discussion: (Key Points) Part 1. Concepts for Variably Tapered Shaping Instruments:
Part 2. GT File Selection and Safe Handpiece-Driven
File Use:
Part 3. GT File Techniques in Large Root Canals with Small Apical Diameters:
Part 4. GT File Techniques in Large Root Canals with Large Apical Diameters:
Part 5. GT File Techniques in Small Root Canals:
Part 6. GT File Techniques in Abruptly Curved Canals:
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Journal: Int. End J. 2001 34(5) 411-413 Submitted by: Paul Slusarz, D.M.D. Purpose: This was a response to the six part series on variable taper instruments (GT or Greater Taper) submitted by Dr. Buchanan. Discussion: Letter from Dr. D. Ricucci:
Response from Dr. L. S. Buchanan:
Comments from the Editor, Professor Paul Dummer:
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Week of October 22, 2001 |
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Author: Al-Fouzan Journal: Inter. Endo. J.: 34, 406-410, 2001 Reviewer: Pranav Vohra, D.M.D. Purpose: To report the case of a mandibular second premolar with four distinct canals. Discussion: According to the author the most
frequent reason for endodontic failure is the
practitioner’s inability to locate all the canals in a tooth and thus, the
incomplete instrumentation leading to failure. Clinical Tips: The author recommends several key indicators for practitioners' to pay attention to which teeth may indicate presence of three or four canals:
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Author: Love, R.M. Journal: Int. Endod J.;34(5):399-405, 2001 Reviewer: Kimberly Pham, DMD Purpose: To identify a mechanism that would explain why cells of E. faecalis could survive within dentinal tubules and maintain the potential to penetrate dentinal tubules. Materials &Methods:
Results and Discussion:
Conclusion: E. faecalis cells remain viable, and maintain the capability to invade dentinal tubules and adhere to collagen in the presence of human serum. This may explain why cells of E. faecalis within radicular dentinal tubules act as a pathogen in failed endodontically treated teeth and their periapical disease involvement. |
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AUTHOR: Andreas Filippi, Yango Pohl, Thomas von Arx JOURNAL: Dental Traumatology: 17: 134-138, 2001 REVIEWER: Donna Salin,D.M.D. PURPOSE: To evaluate the treatment of early stage replacement resorption with intentional replantation using Emdogain, a protein complex that may facilitate cementoblast repopulation of the denuded root surface. Materials &Methods:
RESULTS: During a mean follow-up period of 6.3 months (3-10 months), no signs of recurrence of ankylosis were noted. The horizontally and vertically measured Periotest scores were identical to those obtained on the adjacent teeth. All teeth were functionally and clinically within normal limits. Two teeth had a slightly high percussion tone, but the horizontal as well as vertical Periotest scores were in a normal range. Radiographically, no pathologic findings were present. DISCUSSION: Replacement resorption of teeth replanted after trauma in children and adolescents may result in localized disturbance of jaw growth. Therefore, these ankylosed teeth should be removed. The results of this study suggest that Emdogain may be considered as a treatment option for these cases, as it may prevent or delay replacement resorption of teeth, provided the ankylosis is detected at an early stage. |
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Journal: Dental Traumatol. 2001;17:1-4 Committee: M Flores, JO Andreasen, LK Bakland Prepared by: Nima Dayani, DDS The International Association of Dental Traumatology (IADT), conscious of the variation in treatment of dental trauma, has developed guidelines as a type of consensus statement. These guidelines reflect discussion among members of the IADT as well as review of the literature. Where data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. These guidelines will be published over the next few issues of the Dental Traumatology Journal. This issue contains guidelines for management of trauma in primary teeth. They are presented in the following two tables. Table 1: Treatment guidelines for tooth and/or bone fractures in the primary dentition
Table 2: follow up schedule of acute dental trauma - primary dentition.
S = Splint removal |
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Week of October 29, 2001 |
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Title: Cytotoxic evaluation of root canal filling materials on primary human oral fibroblast cultures and a permanent hamster cell line Author: Kuo-Tai et al Journal: JOE, Vol. 20, No. 9, pgs 571-573 Reviewed by: Andy Schoelch, D.D.S. Purpose: To determine the cytocompatibility of three different extracts of root canal and to compare the cytotoxic response of these materials on two different primary human oral fibroblasts (derived from gingival and buccal mucosa) with one permanent hamster line. Materials and methods: Three root canal sealers were tested
Three cells were tested:
-Cytotoxicity was determined using an assay of tetrazolium bromide reduction Results: All sealers were found to be cytotoxic to all cell lines of the 1-day elute and 3-day elute
-V79 was more sensitive than primary oral fibroblasts Conclusion: It is necessary to continue to investigate endodontic material until some are found that fulfill all the properties of ideal root canal sealers. |
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Author: Kinomoto Y, Carnes D, Ebisu S Journal: JOE 2001; 27(9):574-77 Reviewer: Joe Simoneaux, D.D.S. Purpose: To examine the cytotoxicity of intracanal bleaching agents, sodium perborate (SP) and hydrogen peroxide (HP), on human periodontal ligament cells in vitro. Materials & Methods: Human PDL tissues were obtained from freshly extracted teeth. PDL cells were cultured and grown to confluence on culture wells. Three bleaching agents evaluated were :
PDL cells in culture were mixed with differing concentrations of the bleaching solutions for a period of 24 or 72 hours. The lactic dehydrogenase activity assay, which is based on the measurement of LDH activity released from the cytoplasm of cells with plasma membrane damage, was used to quantitate cytotoxicity. Results: Data indicate that cytotoxicity of bleaching agents was influenced both by concentration of the agents and length of the incubation time. Low cytotoxicity of the SP was confirmed. After 24 hours exposure, SP was less toxic to the PDL cells than HP. After 72 hours, there was no difference in the cytotoxicity of the two solutions. The SP and HP mixture caused the greatest toxicity upon PDL cells after both 24 and 72 hours. Discussion: The mixture of SP and HP has a cumulative bleaching effect due to the fact that when in contact with water, SP decomposes to form HP. However, the greater cytotoxic effect on PDL cells of the mixture may lead to adverse effects when used for nonvital tooth bleaching. Although, SP is considered to be a relatively safe bleaching agent, it was proven to be toxic to the cells of the PDL. The best way to accomplish safe, nonvital bleaching is to prevent penetration of the bleaching agent through the dentinal tubules by the use of protective barriers. The use of heat during bleaching procedures should also be avoided as it accelerated the breakdown of SP into HP. |
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Author: Siqueira, J., Rocas, I., Cezar, J., et al Journal: JOE 2001; 27(9):563-566 Reviewed by: M. Pallante, D.M.D. Purpose: To use a sensitive PCR diagnostic assay to determine the prevalence of black pigmented anaerobic rods in samples taken from infections of endodontic origin. Materials and Methods: Fifty four single rooted teeth from adult patients (18-60), all of them having carious lesions and necrotic pulps were included in this study. Fifteen teeth were sensitive to percussion and 10 were diagnosed with acute periradicular abscesses. Other cases were asymptomatic. Periradicular bone loss was evident in all but 2 teeth. Samples were collected under aseptic techniques. DNA was extracted from samples using TSB-DMSO media. Oligonucleotide primers specific to the following bacterial species were prepared: P. endodontalis, P. gingivalis, P. intermedia, and P. Nigricans. PCR analysis was performed using standard techniques and reaction products were analyzed using gel electrophoresis. Results: PCR assay detected black pigmented anaerobes in
59.3% of examined teeth. They were detected in 9/15 teeth sensitive to
percussion and in 8/10 of the abscess samples. P. endodontalis
was found in 42.6%. P. gingivalis was
found in 27.8%. P. nigrescens in 7.4%. P.
intermedia in 5.6%. 12 of the cases showed more
than one species. The breakdown is as follows:
80% of the abscessed teeth showed black pigmented species. P. endodontalis appeared in 70%. P. gingivalis (40%) P. intermedia
(10%). |
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Authors: C. R. Barthel et.al. Reviewer: Alison Morrison, D.M.D. Purpose: The aim of this in vitro study was to examine the bacteria tightness of root fillings combined with temporary filling materials versus core buildup materials as a coronal seal on a long-term basis. The authors also looked at the effectiveness of a wax in addition to the temporary seal. Materials and Methods: The crowns of 130 extracted single-rooted teeth that had been stored for various times in a 20% ethanol solution were separated from their roots and discarded. The roots were then trimmed to an approximate length of 14mm. Standardized cavities (3mm X 2.5mm and 4mm deep) were prepared with a diamond bur simulating typical access preparations for endodontic treatment. Each root was instrumented to a size #60 master file and was kept 1mm short of the apex. Step back technique and copious irrigation with 2.5% NaOCl were included in this experiment. Apical patency was checked with a #15 file. Each tooth was placed in the ultrasonic with a 5% aqueous solution of EDTA for 20 seconds to remove the smear layer. One hundred twenty of these roots were obturated with laterally condensed gutta-percha combined with AH26. The roots were randomly assigned to six groups. The access cavities were sealed with one of the following: Clearfil, CoreRestore (a core buildup material), Ketac cement (a glass-ionomer cement), or resin-enforced zinc oxide-eugenol cement - IRM. Two experimental groups were filled with wax and glass ionomer or wax and IRM. Here the wax was placed on top of the root canal filling and the rest of the cavity was filled with the temporary filling material. Five of the remaining roots were filled with AH26 and lateral condensation but without a coronal seal and two roots were left empty as positive controls. Three roots were filled with gutta-percha and AH26, and the apices were completely covered with sticky wax. These were used as negative controls. Roots were covered in sticky wax except for the coronal plane and the apical 1-2 mm. They were mounted to 15mm polyethylene tubes (top chamber). These were sterilized and sealed to glass vials (bottom chambers). Five to six mm of the root tips were hung into the sterile broth. Top chambers were inoculated with broth containing 0.25 mg streptomycin/ml and a streptomycin resistant Staphylococcus epidermidis at 10 colony forming units/ml. The bottom chambers were checked for turbidity first daily, then three times per week, then once every fourth week for a period of one year. Results: Two samples had to be discarded due to a failure of the wax seal. All viability checks showed bacterial growth. The fluids from the samples with clear bottom chambers did not show any bacterial growth when incubated. Two bottom chamber samples stained positively for bacterial remnants. For the mean daily leakage there was no significant difference among the groups. At the end of one year, only three samples from the CoreRestore group and two samples from the Clearfil group resisted leakage. But again, no significant difference in the number of leaking samples could be seen among the groups. All negative control samples successfully prevented bacteria from corono-apical passage. Discussion: This study design offers a worst-case scenario. If only a single microorganism had reached the bottom chamber it would only be a matter of time before the liquid turned turbid. Whereas in the human body one could assume that a single microorganism could be fought off by the bodies immune system. It should also be noted that, according to the authors, even bacterial cell walls could elicit and maintain an inflammatory response. S. epidermidis was chosen because it has been shown to penetrate along root fillings in previous studies. IRM was chosen due to its frequent use as a temporary filling material. Clearfil and CoreRestore were chosen in an attempt to differentiate between adhesive materials and non-adhesive materials. In this study they failed too. It should be stressed that this study is looking at the long-term performance of these materials. Due to the fact that all negative control samples prevented bacterial leakage the idea that wax combined with either IRM or glass-ionomer may enhance the seal of access cavities. Conclusion: All examined materials might provide acceptable protection against bacterial leakage in the first four weeks, but in the long-term, Clearfil may be recommended as the material of choice. All samples showed bacterial leakage at one year and because of that, it is suggested to keep the interval between obturation and final restoration as brief as possible. |
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Temple University School of
Dentistry. All contents copyright (C) 1996. All rights reserved. |
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