An Evidence-Based Analysis of the Antibacterial Effectiveness of Intracanal Medicaments
Amanda Law, BDS (Hons), FRACDS, and Harold Messer, MDSc, PhD
Cold Testing Through Full-Coverage Restorations
Stuart O. Miller, DDS, MS, James D. Johnson, DDS, MS, John D. Allemang, DDS, and
James M. Strother, DDS, MS
Effects of Sonicated Enterococcus faecalis Extracts on Interleukin-2 and Interleukin-4 Production by Human T Cells
Ho-Hyun Son, DDD, PhD, SungSam Lim, DDS, PhD, WonJun Shon, DDS, MSD, Hyeon-Sik Kim, DDS, MSD, and WooCheol Lee, DDS, MS
Induction of Vascular Endothelial Growth Factor Gene Expression by Proinflammatory Cytokines in Human Pulp and Gingival Fibroblasts
Shu-Chen Chu, PhD, Chung Hung Tsai, DDS, MHP, Shun-Fa Yang, MS, Fu-Mei Huang, DDS, MS, Ying-Fang Su, DDS, MSD, Yih-Shon Hsieh, PhD, Yu-Chao Chang, DDS, MS, PhD
In Vivo Study on the Biocompatibility of Newly Developed Calcium Phosphate-Based Root Canal Sealers
Jin-Su Kim, DDS, Seung-Ho Baek, DDS, MSD, PhD, and Kwang-Shik Bae, DDS, MSD, PhD
Identification of Resected Root-End Dentinal Cracks: A Comparative Study of Transillumination and Dyes
Henry M. Wright, Jr., DDS, Robert J. Loushine, DDS, R. Norman Weller, DMD, MS,
W. Frank Kimbrough, DDS, MS, Jennifer Waller, PhD, and David H. Pashley, DMD, PhD
Effect of Pitch Length on the Behavior of Rotary Triple Helix Root Canal Instruments
Franck Diemer, DCD, and Paul Calas, DCD, DU
Three-Step versus Single-Step Use of System B: Evaluation of Gutta-Percha Root Canal Fillings and Their Adaptation to the Canal Walls
Juan C. Villegas, DDS, MDS, Takatomo Yoshioka, DDS, PhD, Chihiro Kobayashi, DDS, PhD, and Hideaki Suda, DDS, PhD
Factors Influencing Defects of Rotary Nickel-Titanium Endodontic Instruments After Clinical Use
Peter Parashos, MDSc, Ian Gordon, PhD, and Harold H. Messer, PhD
Clinical Management of a Maxillary Lateral Incisor With Vital Pulp and Type 3 Dens Invaginatus: A Case Report
Sashi Nallapati, BDS
Management of Arsenic Trioxide Necrosis in the Maxilla
Hasan Garip, DDS, Imad M. Salih, DDS, PhD, B. Cem Sener, DDS, PhD, Kamil Göker, DDS, PhD, and Yıldız Garip, DDS, PhD
An Evidence-Based Analysis of the Antibacterial Effectiveness of Intracanal Medicaments
Amanda Law, BDS (Hons), FRACDS, and Harold Messer, MDSc, PhD
The authors reviewed the literature evaluating the antibacterial effectiveness of intracanal medicaments used in the management of apical periodontitis. A PICO (problem, intervention, comparison, outcome) strategy was developed to identify studies dealing with calcium hydroxide, phenolic derivatives, iodine–potassium iodide, chlorhexidine, and formocresol. The final inclusion/exclusion criteria eliminated all papers except five that evaluated calcium hydroxide. The total sample size in the included studies was 164 teeth. Microbiologic sampling was performed before endodontic treatment (S1), after instrumentation and irrigation (S2), and after intracanal medication (S3). At S2, 62% of canals were positive. After medication, 27% still showed detectable growth. Of cultures that were positive at S2, 45% were still positive at S3. Most studies did not address issues of culture reversals or false positive and false negative cultures. The main component of antibacterial action appears to be associated with instrumentation and irrigation, although canals cannot be reliably rendered bacteria free. Calcium hydroxide remains the best medicament available to reduce residual microbial flora further.
Cold Testing Through Full-Coverage Restorations
Stuart O. Miller, DDS, MS, James D. Johnson, DDS, MS, John D. Allemang, DDS, and
James M. Strother, DDS, MS
Endodontic diagnosis often requires thermal testing through porcelain fused-to-metal (PFM) and all-ceramic restorations. The purpose of this study was to measure and compare the temperature change during thermal testing by three commonly used methods occurring at the pulp-dentin junction (PDJ) of nonrestored teeth and teeth restored with full coverage restorations made of PFM, allporcelain, or gold. The methods used to produce a thermal change were (a) an ice stick, (b) 1,1,1,2-tetrafluoroethane (TFE), and (c) carbon dioxide snow. A thermocouple measured temperature changes occurring at the PDJ in 10 extracted premolars when thermal tested by each method over a period of 30 seconds. Temperature reduction was also measured for the same samples restored with full gold crowns, PFM, and Empress crowns. Results showed intact premolars and those restored with PFM or all-ceramic restorations to respond similarly to thermal testing. In these teeth, TFE produced a significantly greater temperature decrease than carbon dioxide snow between 10 and 25 seconds (p < 0.05). In conclusion, application of TFE on a saturated #2 cotton pellet was the most effective method for producing a temperature reduction at the PDJ of intact teeth and those restored with gold, PFM, and all-porcelain when testing for less than 15 seconds.
Effects of Sonicated Enterococcus faecalis Extracts on Interleukin-2 and Interleukin-4 Production by Human T Cells
Ho-Hyun Son, DDD, PhD, SungSam Lim, DDS, PhD, WonJun Shon, DDS, MSD, Hyeon-Sik Kim, DDS, MSD, and WooCheol Lee, DDS, MS
In the present authors’ previous study, sonicated Enterococcus faecalis extracts were shown to suppress the cell cycle progression of human lymphocytes. To study the effect of this microorganism on the function of lymphocytes, the authors investigated the levels of interleukin-2 (IL-2) and interleukin-4 (IL-4) production by T lymphocytes before and after the addition of sonicated E. faecalis extracts. In this study, levels of IL-2 and IL-4 produced from T cells were evaluated by using the quantitative sandwich enzyme immunoassay technique. In response to phytohemagglutinin (PHA) stimulation, T cells produced increased levels of IL-2 and IL-4. However, the expressions of both cytokines were significantly inhibited when PHAactivated T cells were preexposed to 12.5 _g/ml and 25 _g/ml of sonicated E. faecalis extracts (p < 0.05). This effect was concentration-dependent, because the levels of IL-2 and IL-4 expressions were not affected by the addition of a low concentration (5 _g/ml) of sonicated extract. These findings suggest that Th1 and Th2 immunosuppression mediated by E. faecalis could be a part of the pathogenic mechanism of the endodontic failure associated with this microorganism.
Induction of Vascular Endothelial Growth Factor Gene Expression by Proinflammatory Cytokines in Human Pulp and Gingival Fibroblasts
Shu-Chen Chu, PhD, Chung Hung Tsai, DDS, MHP, Shun-Fa Yang, MS, Fu-Mei Huang, DDS, MS, Ying-Fang Su, DDS, MSD, Yih-Shon Hsieh, PhD, Yu-Chao Chang, DDS, MS, PhD
Vascular endothelial growth factor (VEGF) enhances the permeability of blood vessels, which is an important vascular change observed during inflammatory processes. The purpose of this in vitro study was to investigate the effect of proinflammatory cytokines on the expression of VEGF mRNA gene in human pulp and gingival fibroblasts. Interlukin-1_ (IL-1_) and tumor necrosis factor-_ (TNF-_) were used to evaluate VEGF mRNA gene expression in human pulp and gingival fibroblasts. The levels of mRNAs were measured by quantitative reverse-transcriptase polymerase chain reaction analysis. Both IL-1_ and TNF-_ induced significantly high levels of VEGF mRNA gene expression in human pulp and gingival fibroblasts (p<0.05). In addition, TNF-_was found to be more effective in the induction of VEGF mRNA gene expression in pulp than gingival fibroblasts (p<0.05). Moreover, IL-1_was found to be more effective in the induction of VEGF mRNA gene expression than TNF-_in gingival fibroblast cultures (p<0.05). These results indicate that proinflammatory cytokines can induce VEGF mRNA gene expression, and such an effect may partially contribute to the destruction of pulpal and periapical tissues through promoting expansion of the vascular network coincident to progression of the inflammation.
In Vivo Study on the Biocompatibility of Newly Developed Calcium Phosphate-Based Root Canal Sealers
Jin-Su Kim, DDS, Seung-Ho Baek, DDS, MSD, PhD, and Kwang-Shik Bae, DDS, MSD, PhD
This study compared the biocompatibility of two new calcium phosphate-based root canal sealers (CAPSEAL I, CAPSEAL II) with another type of commercially available calcium phosphate sealer (Apatite Root Sealer type I, Apatite Root Sealer type II) and a zinc oxide eugenol-based sealer (Pulp Canal Sealer EWT) after implanting them in the subcutaneous tissue of rats. After 1, 2, 4, and 12 weeks, the tubes were removed with the surrounding tissues. The tissue reactions were graded as being mild or 1, moderate or 2, and severe or 3 after a histopathological examination. The results were analyzed statistically with the Kruskal-Wallis test. The biocompatibility of the materials was interpreted according to the Federation Dentaire Internationale criteria (1980). The inflammatory reactions decreased with time. The new sealers showed a lower tissue response than any of the other sealers in all the experimental periods. All the tested sealers showed an acceptable biocompatibility.
Identification of Resected Root-End Dentinal Cracks: A Comparative Study of Transillumination and Dyes
Henry M. Wright, Jr., DDS, Robert J. Loushine, DDS, R. Norman Weller, DMD, MS,
W. Frank Kimbrough, DDS, MS, Jennifer Waller, PhD, and David H. Pashley, DMD, PhD
The dilemma of diagnosing and possibly treating dentinal cracks continues to present a challenge in endodontics. The purpose of this in vitro study was to compare the effectiveness of transillumination and dyes in identifying root-end dentinal cracks. Fifty maxillary central incisors were decoronated, and the canals were instrumented to an ISO size 50 at the working length. The apical 3 mm of the roots was resected, and cracks were artificially created in the apical dentin. Four independent examiners evaluated the root ends at _8 magnification with a surgical operating microscope using transillumination (group 1), sodium fluorescein dye (group 2), caries detect dye (group 3), methylene blue dye (group 4), and methylene blue plus transillumination (group 5). The examiners’ ability to identify root ends correctly with and without cracks was analyzed by comparing the data with the predetermined standard (cracked and noncracked) using logistic regression analysis. All techniques used were shown to be more effective than random chance at diagnosing cracks. The areas under the curve of the different techniques were as follows: transillumination, 0.81 (95% confidence interval [CI], 0.69–0.93); sodium fluorescein, 0.72 (95% CI, 0.58–0.86); caries detector, 0.76 (95% CI, 0.63–0.89); methylene blue, 0.70 (95% CI, 0.55–0.84); and methylene blue plus transillumination, 0.82 (95% CI, 0.70–0.94). Thus, the crack assessment techniques that gave the best discrimination between cracked and noncracked specimens, regardless of rater, was methylene blue plus transillumination. This study emphasizes the usefulness of transillumination along with magnification in detecting dentinal cracks.
Effect of Pitch Length on the Behavior of Rotary Triple Helix Root Canal Instruments
Franck Diemer, DCD, and Paul Calas, DCD, DU
The behavior of nickel-titanium instruments depends largely on the cross-section of the working part. The effect of pitch length was evaluated using two instruments with the same cross-section (triple helix; 0.6% taper). One had a short pitch (0.5 mm at the tip to 0.9 mm at 16 mm at the end of the working part). The other had a long pitch (1.18 mm/2 mm). A dynamometer recorded tensional stress (MHz) and the tendency to screw in (Fz) during simulated canal preparations. Rotational speed was kept constant, and a continuous pecking movement was used. At the end of the preparations, the average Fz was 5.02 N for the shortpitch instrument and 1.47 N for the long-pitch instrument (p < 0.001). The average Mz varied from 0.88 N (short pitch) to 0.35 N (long pitch). Increasing the pitch decreased torsional load sharing and the tendency to screw in.
Three-Step versus Single-Step Use of System B: Evaluation of Gutta-Percha Root Canal Fillings and Their Adaptation to the Canal Walls
Juan C. Villegas, DDS, MDS, Takatomo Yoshioka, DDS, PhD, Chihiro Kobayashi, DDS, PhD, and Hideaki Suda, DDS, PhD
This study aimed to evaluate the quality of gutta-percha (GP) root canal fillings and their adaptation to the root canal walls, when the System B was used in three steps and a single step to fill three different split-tooth models. Each model was filled 10 times in two different ways. Group A: the System B plugger was used to fill the apical 3mmof the canal in three steps, and then the Obtura II was used to backfill the rest of the canal.
Group B: the System B plugger was inserted just once to a distance 3mm short of the working length and then backfilled as in Group A. Replication of artificial depressions, presence of voids within the GP mass, and presence of spaces between the GP mass and the root canal walls were evaluated and scored. The individual scores of each parameter evaluated were compared between the two groups and statistically analyzed by use of the Mann-Whitney U test. Group A showed statistically significant (p<0.05) better scores than Group B concerning the replication of artificial depressions and spaces between the GP mass and the canal walls. It was concluded that better adaptation of the GP mass to the canal walls in the apical third was obtained when the System B plugger was used in three steps.
Factors Influencing Defects of Rotary Nickel-Titanium Endodontic Instruments After Clinical Use
Peter Parashos, MDSc, Ian Gordon, PhD, and Harold H. Messer, PhD
This study examined used, discarded rotary nickel titanium instruments obtained from 14 endodontists in four countries, and identified factors that may influence defects produced during clinical use. A total of 7,159 instruments were examined for the presence of defects. Unwinding occurred in 12% of instruments and fractures in 5% (1.5% torsional, 3.5% flexural). The defect rates varied significantly among endodontists. Instrument design factors also influenced defect rate, but to a lesser extent. The mean number of uses of instruments with and without defects was 3.3 _ 1.8 (range: 1–10), and 4.5 _ 2.0 (range: 1–16), respectively. The most important influence on defect rates was the operator, which may be related to clinical skill or a conscious decision to use instruments a specified number of times or until defects were evident.
Clinical Management of a Maxillary Lateral Incisor With Vital Pulp and Type 3 Dens Invaginatus: A Case Report
Sashi Nallapati, BDS
A maxillary right lateral incisor with a type 3 dens invaginatus and a large periapical lesion with vital pulp in a separate root canal was treated both nonsurgically and surgically. Care was taken not to expose or devitalize the vital pulp in the main root canal system during the treatment. The signs and symptoms ceased after the treatment, and 4-month recall showed complete bone healing with pulp vitality maintained.
Management of Arsenic Trioxide Necrosis in the Maxilla
Hasan Garip, DDS, Imad M. Salih, DDS, PhD, B. Cem Sener, DDS, PhD, Kamil Göker, DDS, PhD, and Yıldız Garip, DDS, PhD
Historically, pulp-necrotizing agents were commonly used in endodontic treatments. They act quickly and devitalize the pulp within a few days. However, they are cytotoxic to gingiva and bone. If such an agent diffuses out of the cavity, it can readily cause widespread necrosis of gingiva and bone, which can lead to osteomyelitis of the jaws. Although the use of arsenic trioxide can cause severe damage to surrounding tissues, producing complications, it is still used in certain areas in the world. This article presents and discusses two cases of tissue necrosis and their surgical management. These cases showed severe alveolar bone loss in the maxilla, which affected the patients’ quality of life and limited the restorative possibilities. As dentists, we should be aware of the hazardous effects of arsenic trioxide and should abandon its use. Because of its cytotoxicity, there is no justification for the use of arsenic trioxide in the modern dental practice.