The Outcome of Endodontic Retreatment: A 2-yr Follow-up
Fabio G. M. Gorni and Massimo M. Gagliani
Anatomy of the Pulp-Chamber Floor
Paul Krasner and Henry J. Rankow
The Effect of Calcium Sulfate on Hard-Tissue Healing After Periradicular Surgery
Erol S. Apaydin and Mahmoud Torabinejad
Hard-Tissue Healing After Application of Fresh or Set MTA as Root–End-Filling Material
Erol S. Apaydin, Shahrokh Shabahang and Mahmoud Torabinejad
Attachment and Morphological Behavior of Human Periodontal Ligament Fibroblasts to Mineral Trioxide Aggregate: A Scanning Electron Microscope Study
Hanan A. Balto
Diffusion of Ca(OH)2 Associated with Different Vehicles: Chromatographic Study (High-performance Liquid Chromatography)
Izabel Coelho Gomes Camões, Milton Roedel Salles, Orlando Chevitarese and Luiz Nelson Lopes Ferreira Gomes
Comparative Study of Sealing Ability of Two Root–end-filling Materials With and Without the Use of Dentinbonding Agents
Nikolaos Economides, Ioannis Kokorikos, Christos Gogos, Ioannis Kolokouris and Christos Staurianos
A Comparative Study of Crack Development in Stainless-Steel Hedstrom Files Used with Step-back or Crowndown Techniques
Eleni Kosti, Spiros Zinelis, Theodoros Lambrianidis and John Margelos
Microorganisms Growth in Endodontic Citric-Acid Solutions With and Without Microbiological Stabilizer
Leonardo dos Santos Barroso, Sandra Márcia Habitante, Antonio Olavo Cardoso Jorge and Ivan da Silva Faria
Effects of the Hydroxyl Radical and Hydrogen Peroxide on Tooth Bleaching
Kohji Kawamoto and Yasuhisa Tsujimoto
Microhardness of Packable Composites Used as Posts Condensed with Different Methods
Tayfun Alaçam, Özgür Uzun, Bagdagül Helvacioglu Kivanç, Oguz Yoldas, Güliz Görgül, and A. Cemal Tinaz
Effect of Gutta-percha Solvents on Mineral Contents of Human Root Dentin Using ICP-AES Technique
Ali Erdemir, Ayçe Ünverdi Eldeniz, and Sema Belli
In Vitro Antibacterial Activities of Root-Canal Sealers By Using Two Different Methods
Funda Kont Çobankara, Halil Cenk Altinöz, Osman Erganis, Kürsat Kav, and Sema Belli
Predictable Therma-fil Removal Technique Using the System-B Heat Source
Garrett M. Guess
The Outcome of Endodontic Retreatment: A 2-yr Follow-up
Fabio G. M. Gorni, DDS, and Massimo M. Gagliani, MD, DDS
Retreatment is common in endodontics. The purpose of this article was to classify the different clinical situations encountered in retreatment cases and relate them to the outcome after an observation period of 24 months. A total of 425 patients (452 teeth) from 451 patients, consecutively admitted for root-canal retreatment, were monitored during a 24-month period. All teeth (254 molars, 107 premolars, and 91 single-root anterior teeth) were divided into two major categories: teeth with modified anatomy from previous endodontic treatment (root–canal-morphology altered) and teeth in which no significant anatomical changes were made by the former endodontic treatment (root–canal-morphology respected). Although the overall success was 69.03%, the success in the root–canal–morphology-respected group was 86.8% and in the root–canal–morphology-altered group 47% (Mann-Whitney U test p < 0.0001). The clinical success of an endodontic retreatment seems to depend on whether alterations in the natural course of the root canals were caused by previous root-canal treatment.
Anatomy of the Pulp-Chamber Floor
Paul Krasner, DDS, and Henry J. Rankow, DDS
Locating the number and position of orifices on pulp-chamber floors can be difficult. This is especially true when the tooth being treated is heavily restored, malposed, or calcified. After evaluating 500 pulp chambers of extracted teeth, new laws for finding pulp chambers and root-canal orifices are proposed. The use of these laws can aid in the determination of the pulp-chamber position and the exact location and number of root canals in any individual tooth.
The Effect of Calcium Sulfate on Hard-Tissue Healing After Periradicular Surgery
Erol S. Apaydin, DDS, MS, and Mahmoud Torabinejad, DMD, MSD, PhD
The purpose of this study was to determine the effect of calcium sulfate (CS) on cementum deposition and osseous healing after periradicular surgery. The root canals of 24 mandibular premolars in four 2-yr-old beagle dogs were endodontically treated, followed 2 weeks later by periradicular surgery. Mineral trioxide aggregate (MTA) was used as root–end-filling material. The right or left side was assigned at random to receive CS alphahemihydrate or no material in the osteotomy sites before closure. The animals were killed after 4 months. Hard-tissue healing was analyzed histomorphometrically. All samples displayed evidence of cementum deposition adjacent to the root-end fillings and bone regeneration in the osteotomy sites. The data was analyzed using the Mann-Whitney U test, comparing the scores for cementum and osseous healing of the two groups at significance level of alpha _ 0.05. The results indicated that placement of CS in osteotomy sites after periradicular surgery does not significantly affect periradicular healing.
Hard-Tissue Healing After Application of Fresh or Set MTA as Root–End-Filling Material
Erol S. Apaydin, DDS, MS, Shahrokh Shabahang, DDS, MS, PhD, and Mahmoud Torabinejad, DMD, MSD, PhD
The purpose of this study was to compare the effect of fresh mineral trioxide aggregate (MTA) with set MTA on hard-tissue healing after periradicular surgery. The root canals of 24 mandibular premolars in four 2-yr-old beagle dogs were filled with MTA. Two weeks later the root ends of half of the samples were surgically exposed and resected to the set MTA within the canals. After exposing and resecting the other 12 root ends, they were prepared with ultrasonic instrumentation and preparations were filled with fresh MTA. After 4 months, the animals were killed. Hard-tissue healing was analyzed histomorphometrically. The results indicated that although freshly placed MTA resulted in a significantly higher incidence of cementum formation (12 of 12 versus 8 of 12, p _ 0.028), there is no significant difference in the quantity of cementum or osseous healing associated with freshly placed or set MTA when used as root–end-filling material.
Attachment and Morphological Behavior of Human Periodontal Ligament Fibroblasts to Mineral Trioxide Aggregate: A Scanning Electron Microscope Study
Hanan A. Balto, BDS, MSc
The attachment and morphology of human periodontal ligament fibroblasts to mineral trioxide aggregate (MTA) was evaluated using a scanning electron microscope. The material was placed at an apical cavity of 30 single-rooted slices of extracted human teeth. The specimens were divided into two groups of 15 root slices each (freshly mixed and set state). For each experimental group, five root slices were used per observation period (4, 8, and 24 h). A set of two glass slides was used per observation period for the control group. The experiments were performed in tissue-culture cluster 96-well plates in which 1 ml of human periodontal ligament fibroblast cell suspension was placed over the MTA filling and the control glass slides. For the positive-control group, 0.5 ml of methyl methacrylate 2% (vol/vol) was added to the cell suspensions before being dispensed into the wells. Results showed the normal cell morphology in the negative controls. Few round cells with less smooth surfaces and many rough blebs were seen in the positive control, and most of these cells did not show any attachment to the substratum. Similar observations were seen with the freshly prepared- MTA group. In the set-MTA group, cells were round and flattened, displayed smooth surfaces, and appeared to be tightly attached to MTA. It was concluded that the quality and quantity of cell attachment to the retrofilling material could be used as a criterion to evaluate material’s toxicity. This research (FN#1077) is registered with the College of Dentistry research center, King Saud University, Riyadh, Saudi Arabia. The author thanks the administration of the King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, and in particular Dr. M. N. Al-Ahdal for providing the use of the Molecular Virology and Infectious Disease Laboratory, Mr. Yunus Siddiqui for his support, and Dr. Saad ALNazhan for his assistance in preparing the manuscript.
Diffusion of Ca(OH)2 Associated with Different Vehicles: Chromatographic Study (High-performance Liquid Chromatography)
Izabel Coelho Gomes Camões, Milton Roedel Salles, Orlando Chevitarese, and Luiz Nelson Lopes Ferreira Gomes
Using high-performance liquid chromatography (HPLC), small amounts of liquid samples in which 25 premolar human teeth were immersed were evaluated. Each tooth was immersed separately in 800-ml flasks with distilled ultra-pure deionized water and remained there for 1678 h after the filling of their canals with Ca(OH) 2 associated with different vehicles: group 1: polyethylene glycol and colophon (Calen); group 2: glycerin and camphorated paramonochlorophenol; group 3: camphorated paramonochlorophenol; group 4: glycerin and tricresol formol; and group 5: anesthetic solution (Citanest). Five polyethylene tubes were filled with each of these pastes and placed unsealed in similar flasks. At the end of this period, HPLC analyses of the aqueous medium related to each group were performed to detect other substances that had diffused from the pastes used in the canals of the teeth other than calcium and hydroxyl ions. Although the groups presented different maximum peaks when there was no barrier, they all showed higher values than when the tooth was present. At least 15 substances other than Ca2— and OH— were detected in the aqueous medium of group 4. Analyzing the HPLC graphs, we concluded that not only Ca2— and OH—, but also a considerable quantity of other components of the pastes diffused through the dentine and reached the external root surface.
Comparative Study of Sealing Ability of Two Root–end-filling Materials With and Without the Use of Dentin-bonding Agents
Nikolaos Economides, DDS, MSc, PhD, Ioannis Kokorikos, DDS, Christos Gogos, DDS, Ioannis Kolokouris, DDS, PhD, and Christos Staurianos, DDS, PhD
The purpose of this study was to examine microleakage of two root-end-filling materials with and without the use of bonding agents. For microleakage measurement a fluid transport model was used. Sixty single-rooted teeth were used in this study. They were prepared with step-back technique and then an apicoectomy was performed. Then the teeth were divided into four groups. Group A were filled with Fuji II LC glass-ionomer cement, group B were filled with Fuji II LC and a new bonding agent, Fuji Bond, group C were filled with Admira composite resin, and group D were filled with Admira and Admira Bond, a new bonding agent. At 24 h, 1 month, and 2 months after filling the leakage along these filling materials was determined under a low pressure of 0.1 atm. At all experimental times, glass-ionomer groups showed significantly less microleakage than resins groups. Between Admira and Admira Bond groups, significantly less leakage was observed in the root sections with Admira Bond at 24 h.
A Comparative Study of Crack Development in Stainless-Steel Hedstrom Files Used with Step-back or Crown-down Techniques
Eleni Kosti, DDS, Spiros Zinelis, PhD, Theodoros Lambrianidis, PhD, and John Margelos, DDS
The purpose of this study was to evaluate the effect of step-back (SB) and crown-down (CD) techniques on crack development of stainless-steel Hedstrom files (H-files). Ninety-seven mesial root canals of freshly extracted human mandibular molars were selected. Six sets of H-files (#15, #20, and #25 ISO size each) were used with SB and CD techniques for the chemomechanical preparation of 8, 16, and 24 root canals using 2.5% NaOCl as an irrigant and EDTA gel as a chelating agent. Files were sterilized in an autoclave between successive uses. A seventh unused set served as control. After macroscopic examination all files were embedded in epoxy resin, ground, polished, and studied under a metallographic microscope. The maximum crack size of each file was measured by means of standard image-analysis procedures. Macroscopically the files presented no signs of plastic deformation, apart from a file #15, used with SB technique, which fractured after 16 root-canal preparations. The microscopic examination showed no cracks: on control files, on files used with the CD technique for 8 and 16 cycles, on file #20 used with the SB technique for 8 and 16 cycles, as well as on file 25 used with the SB technique for 8 cycles. Cracks were found on H-file #15 used with the SB technique for 8 and 16 cycles, on file 25 used with the SB technique for 16 cycles, and on all files used for 24 cycles with both SB and CD techniques. Under the conditions of this study it was concluded that the instrumentation technique is deeply implicated in the crack development. Crack propagation was accelerated when SB technique was used.
Microorganisms Growth in Endodontic Citric-Acid Solutions With and Without Microbiological Stabilizer
Leonardo dos Santos Barroso, DDS, MSc, Sandra Márcia Habitante, DDS, MSc, PhD, Antonio Olavo Cardoso Jorge, DDS, MSc, PhD, and Ivan da Silva Faria, BS, MSc
The purpose of this study was to determine if citric- acid solutions for endodontic use can become contaminated and if the addition of a microbiological stabilizer to the acid would modify this situation. Five types of microorganisms were inoculated in tubes containing 10% citric-acid solutions, pH 1.8 (group A1), and 10% solution, pH 1.8, combined with 0.1% sodium benzoate (group A2). The results demonstrated that solutions of group A1 were contaminated with Candida albicans in 100% of the tubes, Escherichia coli in 80%, and Enterococcus faecalis in 50%. When stabilizer was added (group A2), C. albicans grew in only 30% of tubes and all bacterial species were neutralized.
Effects of the Hydroxyl Radical and Hydrogen Peroxide on Tooth Bleaching
Kohji Kawamoto, DDS, and Yasuhisa Tsujimoto, DDS, PhD
The mechanisms of bleaching of discolored coronal teeth using hydrogen peroxide (H2O2) were investigated. In a scanning–electron-microscopy study, the intertubular dentin and peritubular dentin were dissolved by high concentrations of H2O2, which is used for bleaching. The X-ray diffraction study showed that hydroxyapatite was not influenced by H2O2. In an electron–spin-resonance study, more hydroxyl radical (· OH) was detected as the H2O2 concentration was increased. When amino acids that are core components of dentin proteins, such as proline and alanine, were added to H2O2, the generation of · OH decreased, but there was no change when glycine was added. A nuclear–magnetic-resonance study showed that proline was degraded completely by H2O2, the structure of alanine changed slightly, and glycine was not affected by H2O2. It is suggested that H2O2 and · OH do not influence the inorganic tissue of dentin but attack the organic component of dentin. These facts suggest that · OH has the main role in tooth bleaching with H2O2.
Microhardness of Packable Composites Used as Posts Condensed with Different Methods
Tayfun Alaçam BDS, PhD, Özgür Uzun, BDS, Bagdagül Helvacioglu Kivanç, BDS, Oguz Yoldas, BDS, PhD, Güliz Görgül,BDS, PhD, and A. Cemal Tinaz, BDS, PhD
The purpose of this in vitro study was to evaluate the microhardness of packable composite compacted with hand or ultrasonic pluggers in post spaces. A total of 168 extracted human anterior teeth were prepared with Gates Glidden and ParaPost drills after obturation. A primer and a dentin-bonding agent were applied to the etched surface. Half of the specimens were compacted with an ultrasonic tip and the other half with a mechanical hand compactor and all specimens were polymerized for each increment. The roots were then sectioned horizontally from 0, 2.5, 3, 3.5, 4, 4.5, and 5 mm starting from the coronal and sliced 2.5-mm long. The microhardness test was applied to each specimen. There were statistically significant differences between ultrasonically and hand-condensed groups in whole specimens (p < 0.001). There were no significant differences between groups of 0, 2.5, and 3 mm until 3.5 mm was reached. After 3.5-mm depth, there were significant differences between the groups (p < 0.001). Ultrasonic condensation of packable composites provided mechanical advantage over hand condensation in root canals measuring microhardness in different depths. However, when microhardness was measured at different depths, values decreased after the depth of 3.5 mm in both condensation groups.
Effect of Gutta-percha Solvents on Mineral Contents of Human Root Dentin Using ICP-AES Technique
Ali Erdemir, DDS, PhD, Ayçe Ünverdi Eldeniz,, and Sema Belli, DDS, PhD
The purpose of this in vitro study was to evaluate the mineral contents of root-canal dentin before and after treatment with two commonly used gutta-percha solvents: chloroform and halothane. Twenty extracted human premolars, whose crowns and apical thirds had been removed, were used. Pulp tissues were removed and the teeth were randomly divided into two groups including 10 teeth each. Root canals were enlarged with Gates Glidden burs (#1, 2, and 3). Dentin chips were obtained and saved in plates to serve as a control. Root–canal-dentin walls were then treated with chloroform or halothane for 15 min. Dentin chips were again obtained using Gates Glidden burs (#4, 5, and 6). The levels of five elements, calcium, phosphorus, magnesium, potassium, and sulfur, in each specimen were analyzed using ICP-AES (inductively coupled plasma atomic emission spectrometry) technique. Changes in the levels of the chemical elements were recorded. Differences between the groups were statistically analyzed using Mann-Whitney U test. There was a significant decrease in Ca level and significant increase in Mg level after treatment with halothane (p < 0.05). There was a significant increase in Mg level after treatment with chloroform. The changes in other elements levels after treatment with gutta-percha solvents were minimal and statistically not significant (p > 0.05). As a result it was concluded that gutta-percha solvents have effect on mineral contents of root dentin.
In Vitro Antibacterial Activities of Root-Canal Sealers By Using Two Different Methods
Funda Kont Çobankara, DDS, PhD, Halil Cenk Altinöz, DDS, PhD, Osman Erganis, DVM, PhD, Kürsat Kav, DVM, and Sema Belli, DDS, PhD
The purpose of this in vitro study was to evaluate the antibacterial activity of five different root-canal sealers (RoekoSeal, Ketac-Endo, AH Plus, Sealapex, Sultan). With the use of Enterococcus faecalis as a test organism, both the agar-diffusion test (ADT) and direct-contact test (DCT) were performed. For DCT, sealers were mixed and placed on the sidewall of microtiter plate wells. A 10-µl bacterial suspension was placed on the tested material samples. Bacteria were allowed to directly contact to the sealers for 1 h at 37°C. Bacterial growth was then spectrophotometrically measured through every 30 min for 19 h by using an Anthos Labtec HT 2. For ADT, a 200-µl bacterial suspension was spread on brain-heart infusion agar plates. Freshly mixed sealers were poured into uniform wells punched in the agar. After periods of incubation at 37°C for 24 h and 7 days in humid atmosphere, the zones of inhibition of bacterial growth on agar plates were observed and measured. Ketac-Endo, Sultan, andAHPlus had similar results for DCT. These sealers were more potent bacterial-growth inhibitors than Sealapex and RoekoSeal. According to ADT, RoekoSeal showed no antibacterial activity. There was no significant difference among AH Plus, Sealapex, and Sultan (p>0.05). Ketac-Endo demonstrated lower antimicrobial activity than these sealers (p < 0.05). Time had no effect on the antibacterial activity of the tested sealers (p>0.05). The antibacterial efficiency of the materials varied according to the tests used. It was concluded that the technique, time, and ingredients of the tested material can affect the results of the microbiological studies.
Predictable Therma-fil Removal Technique Using the System-B Heat Source
Garrett M. Guess, DDS
A clinical tip is suggested to assist in the removal of Therma-fil obturators during conventional endodontic retreatment. Using a heat source such as the System-B, the plastic carriers that are normally an obstacle to retreatment can be efficiently removed using the technique described.