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Week of November 7, 2000 |
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Author: Ricucci, Grondahl & Bergenholtz Journal: OOO 2000;90:354-9. Prepared by: Thomas M. Goebel Purpose: To evaluate the association between coronal restoration integrity and presence of periapical bone lesions in root-filled teeth several years after root canal therapy. M & M: This is a matched, retrospective cohort study including patients whom received initial root canal therapy and restorative treatment in a private dental clinic over a period of 14 years. A total of 733 patients received endodontic therapy but 210 never returned for clinical or radiographic follow-up. Follow-up data had been collected for 523 patients (71%) for 1 or more years after completion of endodontic treatment. Patients with a follow-up period of less than 3 years were excluded from the study so that existing periapical lesions would have time enough to heal. This limited the sample size to 339 patients with 564 teeth. From this pool, all patients at follow-up with teeth with deep caries or missing restoration were classified as "open group." Patients with intact restorations were classified as the "intact group." Cases were matched based upon pulpal diagnosis, periapical diagnosis, tooth type, observation period, age of patient, quality of root filling & presence or absence of post. One tooth per patient was selected for the study. Teeth were excluded from the study if radiographs were poor or if the apical region was not clearly seen in all radiographs. 55 patients fit the "open" group. All endodontic procedures had been performed using the standardized protocol and 1% NaOCl. Vital teeth were treated in 1 visit while necrotic teeth were treated in 2 visits with an intracanal medicament. Data was collected at follow-up appointments. Coronal aspect of the radiographs was covered up with opaque tape during apical evaluation so that the examiner did not know which group the tooth belonged to. Absence or presence of an osteolytic lesion was determined through the joint assessment between 2 examiners. Comparisons of 55 matched pairs of "open" & "intact" teeth were carried out with McNemar chi-square test. Results: Mean age for the "open" group was 35.4 yr. and 30.6 for the "intact" group. 95% of teeth were deemed adequately filled. 14 matched pairs for posts occurred. Follow-up radiographs had 14 periapical lesions, 10 "open" teeth & 4 "intact" teeth. 15 teeth (7 "open," 8 "intact") had an unclear periapical condition. 81 teeth were found to have a normal periapical status. Of the matched pairs, 43 of the 55 (78%) had identical periapical conditions. Of the 14 teeth with lesions at follow-up examination, 5 lesions had developed after the completion of treatment (3 "open", 2 "intact"). The remaining lesions (7 "open", 2 "intact") were clearly reduced in size in comparison with the preop condition. The statistical ratio for a lesion to be present in the "open" group was 3.0, which was not statistically significant. Conclusion: Only 10 of 55 teeth (18%) that had exposure to the oral environment had osteolytic lesions at the last follow-up exam. Of those 10 teeth, 7 had lesions prior to treatment but were clearly reduced in size & 3 had lesions that emerged after therapy. This data suggests that the problem of coronal leakage may not be of such a great clinical importance provided that instrumentation & root fillings are carefully performed. |
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Week of November 14, 2000 |
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Journal: International Endodontic Journal, 33 (5) : 421. September 2000. Author: A. Jaunberzins, J.L. Gutman, D.E. Witherspoon & R.P. Harper Prepared by: Greg Dearing, D.M.D. Purpose: To examine the effects of calcium hydroxide, transforming growth factor-beta, and their co-administration on TGF beta(1)and IL-6 synthesis by early (subculture1) and late (subculture 5) osteoblast cultures. Methods and Materials: Early and late cultures were established using bone cells harvested from 21 day old fetal rat calvaria. Cell cultures of both early and late osteoblasts were divided into 4 groups: Group #1, control; Group #2, cells challenged with Ca(OH)2; Group #3, cells challenged with TGF-beta1; Group #4, cells challenged with Ca(OH)2 and TGF-beta(1) in combination. TGF-beta(1) and Il-6 levels for all groups were determined using ELISA methodology. Results: ANOVA and TUKEY HS analyses revealed that osteoblasts of groups 3 and 4 significantly increased (p<0.001) TGF-beta(1) synthesis in both early and late cultures of osteoblasts. IL-6 was not detected in any of the groups considered in this study. Conclusions: Exogenous TGF-beta(1) has an autocrine effect on cell cultures of osteoblasts. Administration of TGF-beta(1) alone or in combination with Ca(OH)2 increases the synthesis of TGF-beta(1) in osteoblast cultures. Ca(OH)2 and TGF-beta(1) are compatible when placed in a culture of osteoblasts. Ca(OH)2 provides a favorable environment for the anabolic effects of TGF-beta(1).
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Author: Shalabi et al Journal: Int End J , 33, 2000 Reviewed by: Brian Frey Purpose:
M&M:
Results:
Conclusion:
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Author: Gilhooly, R.M.P., et al Source: International Endodontic Journal, 33, 415- 420, 2000 Prepared by: Nima Dayani, DDS Purpose: To evaluate the radiographic quality and sealability of multiphase gutta-percha technique and to compare it with cold lateral condensation of gutta-percha in curved canals. Introduction: Cold gutta-percha relies heavily on root canal sealer to address the problem of the accessory anatomy. However, there are a number of warm gutta-percha methods available where the movement of filling materials to the accessory canals is possible. Materials and Methods: A total of 108 human, freshly extracted teeth, with single curved canal, were allocated to two identical groups of 54 teeth. Working length, apical diameter, and angle of curvature were measured (p 416) and then the teeth were distributed between two groups, so that both groups were identical. All the teeth were prepped with NiTi rotary instruments in a crown down fashion to a final apical size of 35, the smear layer was removed with 17% EDTA and NaOCl. One experimental group was obturated with traditional cold lateral and Extended Working Time Tubliseal (Syborn/Kerr). The other experimental group was obturated using multiphase gutta-percha technique (Alphaseal) and the same sealer. Multiphase Technique: (FYI) In this technique, thermo-mechanical compaction has been combined with thermo-plasticized gutta-percha in a technique termed multiphase obturation. A nickel-titanium rotary condenser simultaneously introduces two phases of gutta-percha (alpha and beta) into root canal, which are dispensed form preheated syringes at 70º C. The Alphaseal system consists of two phases of gutta-percha (Alpha and Beta) in separate pre-filled, disposable syringes and a portable heater. The gutta-percha is warmed in the heater and then extruded onto a size 25/04 taper NiTi rotary condenser for placement into root canal. "The syringe of beta phase gutta-percha was removed from the heater and a condenser, mounted on a 16:1 gear reduction hand peace, driven by an electric motor was inserted into it through the hub far enough to cover the one half the "grooved" portion. Steady pressure was applied to the syringe plunger to extrude a layer of beta phase gutta-percha onto the condenser. The gutta-percha coated condenser was then inserted into the syringe of alpha phase gutta-percha far enough to cover three quarter of the beta phase material. The instrument was then inserted immediately into the root canal to a depth of 0.5 mm from the working distance, with the condenser rotating for 1S at 4000-5000 rpm. The condenser was then withdrawn while pressure was applied to one side of the canal, with instrument rotating, until the instrument was completely withdrawn from the canal. Gutta-percha at the orifice was then vertically condensed with an amalgam plugger." Assessment of Obturation: Obturation was assessed based on the following criteria:
Results/ Discussion: Extrusion beyond the apex was significantly more in the multiphase technique. Improved flow of thermo-plasticized gutta-percha also has a disadvantage of extrusion beyond the apex. Also the vertical condensation of the gutta-percha is recommended to counteract the cooling shrinkage, which increases the extrusion, but these teeth had significantly less dye leakage than teeth obturated with cold lateral. In this study, apical dye penetration was significantly lower for multiphase gutta-percha. This was in agreement with other warm techniques. Additionally, lateral condensation of gutta-percha had a better obturation than the multiphase obturation in terms of radiographic quality from the B-L view; however, this did not correlate with the M-D view. Conclusion: Under this study, multiphase obturation had a better sealability, poorer radiographic quality from the bucco-lingual aspect than the lateral condensation. |
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Week of November 21, 2000 |
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Journal : International Endodontic
Journal, 33, 442-447, 2000 Author: B.E. Kells, J. G. Kennedy, P.A. Biagioni & P.J. Lamey Reviewed by: Kimberly Pham, D.M.D. Purpose: This study was designed to observe the thermographic appearance of teeth and to develop a suitable protocol for imaging teeth in human patients using modern TI equipment. Materials and Method: A total of 12 unrestored maxillary lateral incisors in 6 healthy patients were imaged under rubber dam after a 20-min equilibration period . A dedicated software package was used to analyze thermographic data. For each tooth, recordings were made from standardized gingival and incisal sites and temperature gradient is established. A sequence of images of both maxillary central incisors in one patient was stored every 30 sec during a 20-mn equilibration period with and without an air-conditioning unit in operation. Enamel emissivity is defined as the ratio of the radiant power emitted by the surface to that of a blackbody at an identical temperature (A black body is an object which absorbs all radiation.) The emissivity will alter the electromagnetic radiation emitted and consequently the temperature measured at the body surface. Results & Discussion: A consistent temperature gradient (mean 1.28°C ) from gingival area to incisal area was recorded. There were no statically significant differences between right and left sides for the gingival site or the incisal site. Without the air-conditioning, there was a mean tooth surface temperature increase of 1.1°C from 0 to 5 mn of the equilibration period and 0.3°C from 15 to 20 mn. The protocol described is suitable for TI of vital teeth. However TI measured tooth surface temperature only which was extremely sensitive to air currents. A 15 mn acclimatization period under rubber dam was needed to allow stable tooth surface temperature. |
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Author: C.M. Bramante & L.V. Betti Journal: Internat Endo Journal 33(5):463.
September 2000. Classification: Research Evaluation Article Key Words: gutta-percha removal, nickel-titanium, Quantec system, root canal retreatment,
rotary instruments. Reviewed by: Paul Slusarz, D.M.D. Purpose: To evaluate Materials and Methods:
Results: Group 1 – 350 rpm, Group 2 – 700 rpm, Group 3 – 1500 rpm.
Discussion: A speed of 1500 rpm proved to be fastest at allowing
instruments to reach the working length and to remove gutta-percha. This may
have been because the higher speed plasticized the
gutta-percha more quickly. The plasticized gutta-percha would also have
presented less resistance and this may explain why only one instrument
fractured in the 1500 rpm group. However, despite the higher speed, the
amount of apically extruded debris was not greater. Conclusion: Cleanliness and residual debris were equivalent for each group on straight canals, but the use of 1500 rpm speed was more rapid and fewer instruments fractured. |
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Journal: International Endo. J., 33(5): 427-434, September 2000 Author: Cruz, E.V. et al. Reviewed by: Lance Isaac Purpose: The goal of the study was to evaluate the pattern of undergraduate teaching in Philippine dental schools. Materials and Methods: A questionnaire was prepared, designed to
determine details of the teaching of endodontics in
permanent teeth. A letter was addressed to the Dean of the Results:
Discussion / Conclusions: The spread responsibility of endodontic teaching may be seen as beneficial, reinforcing students’ knowledge of a particular topic (though at one school, pulp capping was taught by a periodontist). This points to excess teaching load. The goal should be to meet the requirements of lab courses to have one faculty member for every 25 students. Course manuals are especially indicated in a setting with little individualized instruction. The limited time spent on preclinical exercises also need re-evaluation, in addition to minimum work requirements. There should also be a conscious effort to use endodontic materials and techniques based on current and accepted literature and modalities of treatment. |
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Author: Kimura, Y. et al. Journal: Internt. Endo. Journal 33(5):
468, September 2000 Reviewer: Dr. Mark Wang Case Report:
Discussion & Conclusion:
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Week of November 28, 2000 |
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Title: Quality of Apical Seal in Curved Canals Using Three Types of Spreaders Author: Omar Gani, Ph.D. et al Source: JOE, 26(10), 581, November 2000 Prepared by: Nima Dayani, DDS Purpose: To evaluate the influence of spreader shape on the quality of obturation Introduction: In the present study, authors evaluated the obturation of the apical third of curved canals prepared using step back technique and filled by lateral condensation, with three types spreaders. Materials and Methods: Forty-five maxillary
lateral incisors and maxillary and mandibular
canines with apical curvature were selected.
The gutta percha was the same for groups B and C. Grossman cement was used. The teeth then were decalcified and sectioned at:
from the apex, and then photographed. The following spaces were then outlined on the photographs: gutta percha mass, sealer mass, foreign bodies, and empty space and then there area was measured. Results: The defects noted were fundamentally the lack of adaptation of the master cone to the apical third and scarcity of the sealer. In other cases the layer of sealer was the same or more than the master cone. Empty spaces or large masses of sealer were frequent findings at all four levels. Often, they were spaces created by the spreader and left empty. Presence of foreign body or pulp remnants was not infrequent. Radiogrphically, deficiencies were noted that were coincident with the outer wall of the curvature. Discussion: Allison et al has suggested that better apical adaptation of gutta-percha is achieved by close proximity of the spreader to the apical area. The authors’ study indicated that such proximity of the spreader might not be plausible, as the spreaders tend to follow a straight line and therefore transfer the pressure to dentin rather than gutta-percha. Lack of condensation of gutta-percha was a frequent finding. The author states that the non-adjusted gutta-percha surrounded by a thick layer of sealer was responsible for the apical obturation in sections 1 and 2. The Author concluded that the presence of pulp remnants were due to inability to use barbed broaches in curved canals as well as reduced apical widening associated with step back technique that does not allow adequate cleaning. Empty spaces were not infrequent. In group A, no significant difference was noted in sections 1 and 2, between the maser cone area and the sum of all remaining spaces. In group B, adequate condensation was obtained in all sections, (i.e., statistically significant difference was noted between master cone area and all other areas), while in group C, section 1 was not adequately condensed. Adequacy of condensation:
The author attributed these phenomena to higher flexibility of slightly conical spreaders in groups B and C and pointed tip of the spreaders in group B. Since the master cone in group A was different than those groups B and C, they did comment that it might have influenced the results of group A. The author recommends use of slightly conical spreaders with pointed tips, rigid accessory points that are considerably thinner than the spreader, as well as coating the cones and the root canal with sealer.
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Journal: JOE 26(10): 605-609, November 2000 Author: Viloria, I.L. et al. Reviewed by: Lance Isaac Purpose: To determine the utility of calcium glycerophosphate (Ca-GP) as an alternative to Ca-BGP and to identify the exact structure and composition of an experimentally formed apical barrier after the application of Ca-GP (equal volume of a and b forms) in the experimental model. Materials and Methods:
Results:
Discussion / Conclusions: Medium supplemented with either Ca-GP or Ca-BGP revealed needle-like crystals consistent with OH-AP (hydroxyapatite). Ca-GP is shown to be able to be used as an alternative to Ca-BGP (which is not readily available), and the a form of Ca-GP may also become a substrate for ALP. There was a significant increase in the average value of the Ca/P molar ratio from days 1 to 3, but it did not increase much from day 3 onward (wound healing after pulp capping is also near complete by day 3 in rat incisors). Overall, this study demonstrates that Ca-GP would be a useful biological medication for artificial barrier formation, especially in cases where teeth have a wide apex. |
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Journal: JOE Vol. 26, no. 10 Author: Tasman, Fugen and et al. Prepared by: Gregory Dearing, D.M.D. Purpose: To evaluate the surface tension values of established and potential endodontic irrigants to which a surface active agent had not been added. Cetrexidine, a surfactant containing 0.2% chlorhexidine gluconate solution was included in the measurements. Materials and Methods: The solutions studied were:
Distilled water, Ringer’s solution, Sterile physiologic saline, 2.5% NaOCl, 5% NaOCl, 17% EDTA, 3%H2O2
,Citanest-Octapressin 3%, Ultracaine
DS and Cetrexidine. The surface tension was
measured using the ring method on a DuNouy tensiometer at standard room temp. Results: Cetrexidine = 32, Citanest = 44, Ultracaine = 47, 2.5% NaOCl = 41, 5%NaOCl = 43, 17%EDTA = 46, Ringer’s solution = 68, H2O2 = 63, Saline solution = 66, Distilled water = 70. Discussion: -Ideal irrigant = Antimicrobial, Tissue dissolving, Biocompatible, Good wetability.
-Polysorbate 80 and 0.1% fluorochemical
surfactant added to traditional irrigants has
significantly -With superior properties of irrigants comes the possible need to remove less dentin in root canal preparation because of better penetration of tubules -NaOCl and EDTA show favorable surface tension = Good success? -Limitations = Need a standardized surface active agent for comparative testing |
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Journal: JOE, Vol. 26, No. 10, October 2000 Authors: Reviewed by: Kimberly Pham, DMD Purpose: The purpose of this study is twofold: (1) to investigate the epidemiology of putative pathogens in root canals with apical periodontitis; and (2) to determine the association among the putative pathogens. This work was performed at the molecular level using PCR and dot-blot hybridization. Materials & Methods:
Results & Discussion:
Conclusion: The combining PCR and hybridization is
very useful for detecting bacteria in comparing with culture methods. Most
bacteria more frequently than previous studies were detected include
fastidious organisms such as |
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