Culture-Independent Detection of Eikenella corrodens and Veillonella parvula in Primary Endodontic Infections
I.N. Rôças, DDS, MSc, PhD, J.F. Siqueira Jr, DDS, MSc, PhD
Eikenella corrodens and Veillonella parvula are normal cultivable inhabitants of the oral cavity but their presence in endodontic infections has not been as common as it could be anticipated. This might have been because of shortcomings of culture techniques when it comes to bacterial isolation or identification. The present study intended to survey samples from primary endodontic infections for the presence of E. corrodens and V. parvula using a culture-independent 16S rRNA gene-based nested PCR protocol. Genomic DNA was isolated directly from samples taken from different forms of periradicular lesions, and the presence of E. corrodens and V. parvula was determined by nested PCR. Specificity for each primer pair was confirmed by sequence analysis of PCR products from positive clinical samples. V. parvula and E. corrodens were, respectively, detected in 33% and 14% of the root canals associated with chronic apical periodontitis. Both V. parvula and E. corrodens were found in 10% of the cases diagnosed as acute apical periodontitis. V. parvula and E. corrodens were detected in 21% and 26% of the samples from acute apical abscesses, respectively. In general, species-specific nPCR allowed the detection of V. parvula in 24% and E. corrodens in 18% of the samples taken from primary endodontic infections. Findings confirmed that V. parvula and E. corrodens can take part in the microbiota of primary endodontic infections, but in prevalence values somewhat higher when compared to most of the previous culture studies that had reported recovery of these species.
Preference of Temporary Restorations and Spacers: A Survey of Diplomates of the American Board of Endodontists
Mychel Macapagal Vail, DDS, MSD, Charles L. Steffel, DDS, MSD
The purpose of this investigation was to survey Diplomates of the American Board of Endodontists to determine their preferences in temporary restorations used during and following endodontic therapy and if cotton pellets are used as spacers. The survey asked which primary temporary material was used in anterior and posterior teeth to close access openings. Also, the endodontists were asked if they preferred a double seal and if they used cotton pellets as spacers. Eighty percent (507 of 603) of the surveys were returned. Cavit was the temporary restoration of choice for both anterior and posterior teeth, 48% and 54%, respectively. The majority of Diplomates, 83%, placed a cotton pellet beneath the temporary restorations.
Regulation of ALP Activity by TNF-α on Human Dental Pulp
Tatsu Okabe, DDS, Kiyoshi Matsushima, DDS, PhD
In this study, we examined the effects of TNF-α on Bone morphogenetic protein (BMP-2), Smads (which play intracellular signaling of BMPs) expression and alkaline phosphatase (ALP) activity of human dental pulp (HDP) cells to clarify the mechanism of tertiary dentin formation. The quantity of RT-PCR product for BMP-2 from the HDP cells stimulated by TNF-α is increased. However, ALP activity was not increased on the cells incubated with TNF-α. On the other hand, ALP activity was significantly increased on HDP cells treated with Ammonium Pyrrolidinedithiocarbamate (PDTC, NF- κB inhibitor) groups and combined supplementation of TNF-α and PDTC groups. Furthermore, we examined the effect of TNF-α and PDTC on Smad7 expression using RT-PCR and western blot analysis. Smad7 expression in HDP cells was increased by TNF-α, but decreased by PDTC treatment. These results suggest that NF- κB and Smad7 play an important role in the down regulation of ALP activity by TNF-α on HDP cells.
Characterization of Proteolytic Activities of Fusobacterium nucleatum
Alice Tayoko Ogawa, DDS, MS, Tatiana de Arruda Campos Brasil de Souza, MS, Milton de Uzeda, PhD, Jose V. Jankevicius, PhD, Shiduca Itow Jankevicius, PhD
This investigation attempted to detect the proteolytic activity of Fusobacterium nucleatum in living cells, lysate cells, and supernatant of cultures. The reactions were optimized in their pH, temperature, reaction time, enzyme source, and substrate volume. Synthetic substrates β-naphthylamides (Cys-Na, Ser-Na, Leu-Na, Glu-Na, Lys-Na and BANA), carbobenzoxy L-tirosine p-nitrophenylester (CTN), and natural substrate azoalbumin were used. Reaction occurred with Cys-Na, Ser-Na, and Glu-Na in living cells and with Glu-Na, Leu-Na, and CTN substrates in lysate cells. The supernatant reacted only with Glu-Na. Optimal pH ranged from 6.0 to 7.5, except for CTN (pH 13), and optimal temperature, between 30 and 40°C. Optimal reaction time was 60 min, except for Glu-Na in living cells (40 min), lysate cells (20 min), and CTN substrate (80 min). There was no activity with Lys-Na, BANA, and azoalbumin. Proteolytic activity was assessed by several inhibitors and the presence of metallo, serine, cysteine, and aspartic proteases were detected.
Effect of Orifice Plugs on Periapical Inflammation in Dogs
Shizuko Yamauchi, DDS, MS, Guy Shipper, BDS, MDent, MS, Thomas Buttke, DDS, MS, PhD, Mitsuo Yamauchi, DDS, PhD, Martin Trope, BDS, DMD
Gutta-percha (G) and sealer do not resist coronal leakage. In this study, the effect of orifice plugs using dentin-bonding/composite resin(C) or IRM on coronal leakage was evaluated in vivo. Sixty-one premolar roots in three beagle dogs were instrumented and filled with G and AH 26(S), or G alone. The coronal 2 mm was replaced with C or IRM, or left untreated. The access cavities were kept open for 8 months, the dogs were killed and the periapical regions of the roots were histologically examined. Periapical inflammation was observed in 89% of the group without plugs, but in those with plugs, the occurrence was decreased to 39% (C + G + S), 38% (IRM + G + S) and 58% (C + G), respectively. Furthermore, severe inflammation was observed in 50% of the former group but only 0 to 17% of the latter. The substantial reduction in apical periodontitis by the use of coronal plug underscores the clinical importance of providing an additional barrier to coronal leakage in comparison to that provided by gutta-percha and sealer alone.
Comparative Evaluation of Endodontic Irrigants against Enterococcus faecalis Biofilms
Thomas R. Dunavant, DDS, John D. Regan, B.DentSc, MSc, MS, Gerald N. Glickman, DDS, MS, MBA, JD, Eric S. Solomon, MA, DDS, Allen L. Honeyman, PhD
The aim of this study was to compare the efficacy of root canal irrigants against E. faecalis biofilms using a novel in vitro testing system. Biofilms grown in a flow cell system were submerged in test irrigants for either 1 or 5 minutes. Statistical analysis revealed a significant relationship between test agent and percentage kill of the biofilm bacteria (P < 0.05). No statistically significant relationship between time and percentage kill was found. The percentage kill of the biofilm bacteria was: 6% NaOCl (>99.99%), 1% NaOCl (99.78%), Smear Clear™ (78.06%), 2% chlorhexidine (60.49%), REDTA (26.99%), and BioPure™ MTAD™ (16.08%). Post-hoc analysis showed a significant difference between 1% and 6% NaOCl, and all other agents including Smear Clear™, 2% chlorhexidine, REDTA, and BioPure™ MTAD™ (P < 0.05). Within the parameters of this study, both 1% NaOCl and 6% NaOCl were more efficient in eliminating E. faecalis biofilm than the other solutions tested.
Effect of Intracanal Medicament on the Sealing Ability of Root Canals Filled with Resilon
Ching S. Wang, DDS, Gilberto J. Debelian, DDS, PhD, Fabricio B. Teixeira, DDS, MS, PhD
The purpose of this in vitro study was to investigate the effects of the use of calcium hydroxide as an intracanal dressing on the sealing ability of a thermoplastic synthetic polymer-based root filling (Resilon). Forty-seven single rooted teeth were decoronated and instrumented to ISO sizes 40. The teeth were randomly divided into three experimental groups of 15 roots each. Group 1 was immediately filled. Group 2 and group 3 had calcium hydroxide paste placed with lentulo-spiral filler. After 7 days, calcium hydroxide was removed from the canals with two different techniques: #15 K-file agitated irrigation with 17% Ethylenediaminetetracitic acid (EDTA) (group 2) or ultrasonically agitated irrigation with 17% EDTA (group 3) for 2 min. All teeth were filled with Resilon points and the resin sealer (Ephiphany root canal sealant) using lateral condensation technique. Two teeth were immediately filled with Resilon master point size 40/.04 without sealer to act as a positive control. A split chamber microbial leakage model using Streptococcus mutans was used and the leakage was evaluated daily for a period of 30 days. Overall, 6 of 44 (14%) of samples filled with Resilon points and the resin sealer had microbial leakage. Three samples in group 1 (21%), two samples in group 2 (13%), and one specimen in group 3 (7%) had bacterial leakage. Using the Fisher’s Exact test, there was no statistically significant difference in leakage between the groups with calcium hydroxide dressing and the group without calcium hydroxide (p > 0.05). Under the condition of this study, calcium hydroxide did not adversely affect the seal of the root-canal system filled with Resilon.
Effect of Hygroscopic Expansion on the Push-Out Resistance of Glass Ionomer-Based Cements Used for the Luting of Glass Fiber Posts
Álvaro H. Cury, DDS, Cecilia Goracci, DDS, PhD, Maria Fidela de Lima Navarro, DDS, PhD, Ricardo M. Carvalho, DDS, PhD, Fernanda T. Sadek, DDS, MSc, Franklin R. Tay, BDSc (Hons), PhD, Marco Ferrari, MD, DDS, PhD
This study examined the contribution of hygroscopic expansion of glass-ionomer (GIC) and resin modified glass-ionomer (RMGIC) luting cements to the push-out resistance of fiber posts. Glass fiber posts were luted to post spaces using different cements. Experimental specimens were stored in water, while control specimens were desiccated and stored in mineral oil to eliminate water from intraradicular dentinal tubules and/or the external environment that could have contributed to hygroscopic expansion of the cements. Thin slice push-out tests revealed no difference in retention strengths of resin composite cements that were stored in water or oil. Conversely, GIC and RMGIC cements exhibited increased retention strengths after water sorption. As unfavorable cavity geometry is taxing to dentin bond integrity in root canals, a strategy that relies on increasing the frictional resistance to post dislodgement via delayed hygroscopic expansion of glass-ionomer based materials may be a more pragmatic approach to fiber post retention.
Completeness of Root Canal Obturations: Epiphany Techniques versus Gutta-Percha Techniques
Samuel R. Epley, D MD, Jacob Fleischman, DMD, Gary Hartwell, DDS, Carmen Cicalese, DMD
This project was designed to determine how a new resin based obturation material compared with traditional gutta-percha techniques in its ability to fill the prepared root canal space. Eighty single-rooted palatal and distal roots of extracted human first molars were used. The root canals were instrumented with hand and rotary files and divided into four groups. Gutta-percha and the new resin based material was used with lateral condensation or continuous wave obturation. The roots were sectioned at 1, 3, and 5 mm from the apex and examined under magnification. Using a computer program, the surface areas of voids were calculated and compared. The gutta-percha, lateral condensation method was the only group that demonstrated significantly more voids. There were no statistically significant differences among any of the other three groups.
Mathematical Modeling of Flexural Behavior of Rotary Nickel-Titanium Endodontic Instruments
Danny Low, MScDent, Angela W.L. Ho, MDS, Gary S.P. Cheung, MDS, MSc, Brian W. Darvell, MSc, PhD
The aim of the present study was to establish a mathematical model to characterize the flexural behavior of nickel-titanium (NiTi) rotary instruments. The bending behavior of ProFile (0.06 and 0.04 tapers), K-3 (0.06 taper), Quantec (0.04 taper) with tip size of ISO 25, was assessed by pressing the tip of the static rotary file against a smooth, freely movable, glass surface. The deflected instrument was photographed digitally, and the deflection path was digitized in software, to which data a function was fitted that best described the bending behavior of the instrument. It was found that all instruments deflected in a manner closely resembling a negative exponential function: y = A-e-x/b . The present approach indicated that the analytical difficulties of handling the complex cross-section in tapering spirals in beam-bending theory may be circumvented by a practical and elementary curve-fitting method.
Ultrasound Effects after Post Space Preparation: An SEM Study
Cinzia Serafino, DMD, Giuseppe Gallina, DMD, Enzo Cumbo, DMD, Francesca Monticelli, DMD, Cecilia Goracci, DMD, Marco Ferrari, DMD, PhD
Abstract
The aim of this study was to evaluate the effect of ultrasonic treatment on occlusion of dentine tubules in root canal walls after post space preparation in endodontically treated teeth. Twenty-four premolars were instrumented and filled using warm vertical condensation; after post space preparation, they were divided into two groups. The control group was treated using the etching procedure. The experiment samples were treated with EDTA irrigation and ultrasound activation for 30 s before the etching procedure. The roots were divided and the canal walls were examined under SEM at 1000× magnification. The debris and open tubule marks were observed at 2, 6, and 10 mm levels using a three-step scale and the differences in marks among the groups were tested for statistical significance. The following were observed: (a) A decrease in debris and open tubule marks in the samples treated with ultrasounds and the control group (p < 0.05), (b) no significant differences between the three levels of post space in debris and open tubule marks in the experiment samples, and (c) significant differences between the apical and coronal levels in debris and open tubule marks in the control group.
A Comparison of Cohesive Strength and Stiffness of Resilon and Gutta-Percha
Chad Williams, DMD, Robert J. Loushine, DDS, R. Norman Weller, DMD, MS, David H. Pashley, DMD, PhD, Franklin R. Tay, BDSC (Hons), PhD
The purpose of this study was to compare the cohesive strength and stiffness of Resilon and gutta-percha under dry conditions and after 1 month of water storage to determine if they are stiff enough to reinforce roots. Dog-bone shaped specimens were created and pulled to failure at 3 mm/min in a Vitrodyne universal tester. The apparent modulus of elasticity, percent elongation, and yield stress were measured. Cohesive strength was defined as the yield stress. The data were analyzed using a two-way ANOVA for each outcome (α = 0.05). The results of this study show that the cohesive strength (that is the tensile stress when they begin to flow or break) and modulus of elasticity (or stiffness) of gutta-percha and Resilon are relatively low. Although the results showed statistically significant differences between the physical properties of gutta-percha and Resilon under varied conditions, these differences were not clinically significant. In conclusion, the stiffness of Resilon and gutta-percha is too low to reinforce roots after root canal therapy.
Evaluation of the Tissue Response to MTA and MBPC: Microscopic Analysis of Implants in Alveolar Bone of Rats
Luciano Tavares Angelo Cintra, DDS, MS, Ivaldo Gomes de Moraes, DDS, PhD, Bernabé Pedro Felício Estrada, DDS, PhD, João Eduardo Gomes-Filho, DDS, PhD, Clóvis Monteiro Bramante, DDS, PhD, Roberto Brandão Garcia, DDS, PhD, Norberti Bernardinelli, DDS, PhD
The aim of this study was to evaluate and compare the quantitative and qualitative inflammatory responses and bone formation potential after implantation of polyethylene tubes filled with a new calcium hydroxide containing sealer (MBPc) and ProRoot mineral trioxide aggregate (MTA). There were 48 Wistar rats divided in three groups: Group I (control group) empty polyethylene tubes were implanted in the extraction site; group II and III, polyethylene tubes were implanted filled with ProRoot mineral trioxide aggregate (MTA) and MBPc, respectively. At 7, 15, and 30 days after tube implantation, the animals were killed, the hemi-maxillas were removed and prepared to light microscopic analyses. The scores obtained were submitted to Kruskal-Wallis statistical test (p < 0.05). Significant differences between the materials were not observed. The results showed that both materials had similar biological response.
The Ability of Two Apex Locators to Locate the Apical Foramen: An In Vitro Study
Fábio Luiz Cunha D́Assunção, DDS, MD, Diana Santana de Albuquerque, DDS, MD, PhD, Linalda Correia de Queiroz Ferreira, DDS
The objective of this study was to compare the accuracy of the Root-ZX and Novapex electronic apex locators (EALs) in locating the apical foramen. Forty extracted human teeth were used. The coronal portion of each canal was flared using Gates Glidden drill. Canals were irrigated with 2.5% sodium hypochlorite. The actual length (AL) and electronic length (EL) measurements were made on each specimen separately with both devices with an aid of a K-type file. The results obtained with each EAL were compared with the corresponding control length. The statistical analysis of the results showed EAL reliability in detecting the apical foramen to 89.7% for the Root-ZX and 82.1% for the Novapex, taking the tolerance of ±0.5 mm into account. A paired sample t test showed that there was no statistically significant difference between the accuracy of the devices (p = 0.4305). The results of this study indicate that the Root-ZX and Novapex are useful and accurate devices for the apical foramen location.
A Quantitative Assessment of Efficacy of Various Calcium Hydroxide Removal Techniques
David M. Kenee, DDS, MS, John D. Allemang, DDS, James D. Johnson, DDS, MS, John Hellstein, DDS, Brian K. Nichol, DDS
This study evaluated the amount of calcium hydroxide [Ca(OH)2)] remaining in canals after removal with various techniques including combinations of NaOCl with EDTA irrigation, hand filing, rotary instrumentation, or ultrasonics. The mesial canals of 12 mandibular molars were uniformly instrumented. Teeth were sectioned longitudinally along the length of the instrumented canals. Acrylic jigs were fabricated, allowing reapproximation of the opposing segments. After Ca(OH)2 placement into the canals, four techniques were used for its removal. In the first method, the master apical file was placed to working length in between two 5-ml rinses of NaOCl. The other three techniques combined with the first method either a 2.5-ml EDTA rinse, a rotary file (MAF size) to working length, or passive ultrasonication. Results showed that no technique removed all Ca(OH)2. Rotary and ultrasonic techniques, while not different from each other, removed significantly more Ca(OH)2 than irrigant only techniques. The irrigant only techniques were not different from each other.
In Vitro Radiographic Determination of Distances from Working Length Files to Root Ends Comparing Kodak RVG 6000, Schick CDR, and Kodak Insight Film
Robert T. Radel, DMD, MS⁎, Gary G. Goodell, DDS, MS, MA, Scott B. McClanahan, DDS, MS, Mark E. Cohen, PhD
Previous studies suggest that digital and film-based radiography are similar for endodontic measurements. This study compared the accuracy and acceptability of measured distances from the tips of size #10 and #15 files to molar root apices in cadaver jaw sections using the newly developed Kodak RVG 6000, and the Schick CDR digital systems to digitized Kodak film. Standardized images were taken of files placed 0.5 to 1.5 mm short of true radiographic lengths. Images were imported into Adobe PhotoShop 7.0, thereby blinding observers who measured distances from files to root apices and assessed images for clarity (acceptability). Repeated measures ANOVA and Tukey-Kramer post hoc tests demonstrated that Kodak RVG 6000 images with enhanced contrast produced significantly less measurement error than unenhanced contrast Schick CDR images (p < 0.05) and significantly higher acceptability ratings than all other systems (all p < 0.002). Among these conditions, the newly developed Kodak RVG 6000 system provided the best overall images.
The Effects of Various Additives on Setting Properties of MTA
Paul Kogan, DDS, Jianing He, DMD, PhD, Gerald N. Glickman, DDS, MS, MBA, Ikuya Watanabe, DDS, PhD
Delayed setting times may limit the use of mineral trioxide aggregate (MTA) in endodontic procedures. The purpose of this study was to identify types and amounts of MTA additives to enhance its setting properties. Additives tested include saline, 2% lidocaine, 3.0% NaOCl gel, chlorhexidine gluconate gel, K-Y Jelly, 3% and 5% CaCl2. The setting times were evaluated using a Vicat apparatus; compressive strengths of set materials were evaluated with an Instron machine. NaOCl gel, K-Y Jelly and 5% CaCl2 decreased the setting time to 20 to 25 min; compressive strengths of these set materials were significantly lower than MTA mixed with water (p < 0.05). Because MTA mixed with NaOCl gel demonstrated good working properties and improved setting time, this combination may be a viable option in single visit procedures where compressive strength of the material is not a critical issue.
Combined Endodontic-Periodontic Treatment of a Palatal Groove: A Case Report
Scott A. Schwartz, DDS, Michael A. Koch, DDS, David E. Deas, DMD, MS, Charles A. Powell, DDS, MS
The palatal groove is a developmental anomaly that predisposes the tooth involved to a severe periodontal defect. When further complicated by pulp necrosis, these grooves often present a diagnostic and treatment planning challenge that requires an interdisciplinary treatment approach. This case report describes the successful collaborative management of a maxillary lateral incisor with an extensive palatal groove using a combination of nonsurgical endodontic therapy, odontoplasty, and periodontal regenerative techniques.
Intentional Replantation: A Case Report
Michael R. Cotter, DDS, John Panzarino, DMD
Nonsurgical retreatment and surgical endodontics are not always viable solutions to endodontic disease. Access for retreatment may be limited by posts. Surgical endodontics may be limited by anatomical features including bone thickness and nerve and sinus proximity. Anatomical limitations and complex restorations may prevent implant placement. Intentional replantation is considered by many as a procedure of last resort when nonsurgical or surgical endodontics is contra-indicated. The treatment described demonstrates intentional replantation as a procedure to be considered when endodontic procedures or a dental implant are not possible.
Effectiveness of Dental Computed Tomography in Diagnostic Imaging of Periradicular Lesion of Each Root of a Multirooted Tooth: A Case Report
Kazuhiko Nakata, DDS, PhD, Munetaka Naitoh, DDS, PhD, Masahiro Izumi, DDS, PhD, Kyoko Inamoto, DDS, Eiichiro Ariji, DDS, PhD, Hiroshi Nakamura, DDS, PhD
Radiography by use of the three-dimensional (3D) Accuitomo XYZ Slice View Tomograph (3DX), a device for compact computed tomography in dentistry, was performed as a new diagnostic imaging technique for a patient who needed endodontic therapy. The 3DX was used for examining and diagnosing the presence and expansion of periradicular lesions in each root of a multirooted tooth. High-resolution 3D images were observed and compared with those obtained by routine conventional radiography. It was difficult to diagnose the cause of clinical symptoms by general examinations including the usual intraoral radiography and panoramic radiography. The images obtained by the 3DX, however, clearly showed the apparent presence and expansion of a periradicular lesion in only one root of the multirooted tooth. The 3DX, a newly developed dental computed tomography, provides abundant new image information not attainable by either intraoral radiography or panoramic radiography, and its application for clinical use is very effective for examining and diagnosing regions of interest for endodontic therapy.