Modern Endodontic Surgery Concepts and Practice: A Review
Syngcuk Kim, DDS, PhD, MD(hon), Samuel Kratchman, DMD
Endodontic surgery has now evolved into endodontic microsurgery. By using state-of-the-art equipment, instruments and materials that match biological concepts with clinical practice, we believe that microsurgical approaches produce predictable outcomes in the healing of lesions of endodontic origin. In this review we attempted to provide the most current concepts, techniques, instruments and materials with the aim of demonstrating how far we have come. Our ultimate goal is to assertively teach the future generation of graduate students and also train our colleagues to incorporate these techniques and concepts into everyday practice
A Comparison between In Vivo Radiographic Working Length Determination and Measurement after Extraction
Clayton B. Williams, DDS, Anthony P. Joyce, DDS, Steven Roberts, DDS
The purpose of this study was to compare the difference between the in vivo working length established by viewing a periapical radiograph and the in vitro measurement from the file tip to the apical foramen of the extracted tooth. Twenty-six canals from teeth that had been treatment planned for extraction were accessed under rubber dam isolation. The coronal portion of each canal was flared using Gates Glidden drills, and a K-type file was inserted down the canal until an electronic apex locator indicated that the file had reached the apex. A size 20 K-type file was locked into place with glass ionomer cement at this position. A radiograph was exposed and the tooth was extracted. Each tooth was viewed using a videomicroscope at 30× original magnification, and the distance from the file tip to the most coronal aspect of the major foramen was measured. Six examiners viewed each radiograph and assessed the working length of each canal. χ2 analysis of the data revealed a significant difference (p < 0.01) between the estimation of working lengths and the microscopic measurements. The examiners overestimated the distance between the file tip and the apical foramen of the tooth when the file was placed short, and underestimated the distance when the file was placed long. In conclusion, when the file is short it is actually closer to the apical foramen than it appears radiographically; when it is long it is actually longer than it appears radiographically.
Healing of Apical Periodontitis After Endodontic Treatment With and Without Obturation in Dogs
Mohammad A. Sabeti, DDS, MA, Mohammad Nekofar, DDS, MS, Pouria Motahhary, DDS, MS, Mostafa Ghandi, DDS, James H. Simon, BA, DDS
The principle of obturation of the root canal space is generally accepted. This belief has dominated the field of endodontics despite the absence of credible scientific evidence. Little information is available on the possible relationships between endodontic success and obturation of the root canal system. The present study compares the healing of instrumented and obturated versus instrumented and nonobturated root canal systems with apical periodontitis. Fifty-six root canals in 28 third and fourth bilateral lower premolar teeth with completely formed apices in seven mixed German Shepherd dogs were used. Apical lesions were created by accessing the canals, removing the pulp and leaving them open to the oral environment for 42 days. The teeth in the control group were instrumented, irrigated, and then obturated using a lateral condensation technique with gutta-percha cones and AH26 Plus as the endodontic sealer. The teeth in the experimental group were instrumented and irrigated without obturation. All teeth in both groups were sealed coronally. After 190 days, the animals were euthanized. Vital perfusion with 10% formalin through common carotid artery was performed. Thirty to 40 serial 5-μm thick sections were obtained from each root and stained with hematoxylin and eosin for histological evaluation by observer blinded to the treatment allocation. The control group showed less cementum and dentin resorption in comparison with test group (p < 0.5). No statiscally significant difference was found in other parameters between the control and test groups (p > 0.05). The noteworthy finding of this study was that there was no difference in healing of apical periodontitis between the instrumented and obturated and instrumented and nonobturated root canal system. The success of endodontic treatment ultimately depends on the elimination of the microorganism, host response and mechanical closure (coronal seal) of treated root canals that may provide a potential for future bacterial contamination.
Enterococcus faecalis Adhesin, Ace, Mediates Attachment to Particulate Dentin
William J. Kowalski, DMD, MS, Edward L. Kasper, DMD, MS, John F. Hatton, DMD, Barbara E. Murray, MD, Sreedhar R. Nallapareddy, Ph.D, M. Jane Gillespie, MS, PhD
An enzyme linked immunosorbent assay was developed to assess E. faecalis adhesion to particulate dentin. E. faecalis, OG1RF, which expresses the collagen binding protein (Ace+), and a derivative of OG1RF, TX5256, deficient in the collagen binding protein (Ace−) were grown at 46° C, necessary for in vitro expression of Ace, and at 37° C. E. faecalis binding to dentin was measured at 0, 15, 30, 60, 120, and 360 minutes. Compared to TX5256 and OG1RF grown at 37° C, OG1RF grown at 46° C adhered significantly better at all time points except 15 minutes (p < 0.001) exhibiting maximum binding at 120 minutes (17.4% of a positive control). Type I collagen at 100 μg/ml inhibited dentin binding by OG1RF grown at 46° C in both competition (p < 0.005) and displacement assays (p < 0.046). Immunoaffinity purified anti-Ace IgG at 200 μg of protein inhibited adhesion of OG1RF grown at 46° C to dentin.
Denaturation Temperatures of Dentin Matrices. I. Effect of Demineralization and Dehydration
Steven R. Armstrong, DDS, PhD, Julie L.P. Jessop, PhD, Erik Winn, DDS, Franklin R. Tay, BDSc (Hons), PhD, David H. Pashley, DMD, PhD
The denaturation temperature (Td) of dentin collagen in mineralized versus demineralized teeth was examined as a function of dentin age and the extent of dehydration. Using differential scanning calorimetry, Td of mineralized dentin was shown to be between 160°C to 186°C, depending on whether it was from young or old dentin that was hydrated or dehydrated, respectively. Demineralized dentin exhibited a Td of 65.6°C that increased with dehydration to 176°C. The presence of apatite crystallites or interpeptide bonding increased the Td of demineralized matrices. Interpeptide hydrogen bonding seems to stabilize collagen to thermal challenge. Water breaks interpeptide hydrogen bonds making collagen more susceptible to thermal denaturation. Rises in intracanal temperature are unlikely to cause extensive denaturation of mineralized root dentin walls. However, hydrated or partially dehydrated root canal walls that have been partially demineralized with chelating agents or mild acids may be susceptible to thermal denaturation.
A Fluid Filtration Comparison of Gutta-Percha versus Resilon, a New Soft Resin Endodontic Obturation System
Ryan K. Stratton, DMD, Michael J. Apicella, DDS, Pete Mines, DDS
The purpose of this study was to compare the sealing ability of gutta-percha and AH Plus sealer versus Resilon and Epiphany Resin Root Canal sealer using three different final irrigants with the fluid filtration model. There were 140 teeth prepared using a crown-down method to a size 50 file. The teeth were randomly divided into two groups: (A) GP and AH Plus and (B) Resilon and Epiphany. After removal of the smear layer each group was irrigated with either 5.25% NaOCl, 0.012% chlorhexidine (CHX), or 2% CHX for 10 minutes. Obturation was performed using the continuous wave of condensation. The teeth were stored for 20 days in 100% humidity before testing. Two-way ANOVA analysis indicated significantly less leakage (p < 0.05) using Resilon with Epiphany sealer compared to gutta-percha and AH Plus sealer. There was no statistical significance between any of the irrigants used for either obturation group.
Bacterial Count Comparisons on Examination Gloves from Freshly Opened Boxes Versus Nearly Empty Boxes and From Examination Gloves Before Treatment Versus After Dental Dam Isolation
Jeffrey B. Luckey, DDS, Robert D. Barfield, DMD, Paul D. Eleazer, DDS, MS
Use of gloves in dentistry is primarily for protection of the healthcare worker, yet little information is available regarding potential patient issues such as microbial contamination of gloves before and during use. The purposes of this study were to compare gloves from newly opened boxes with those from boxes that had been in dental operatories until they were nearly empty and to determine if gloves are contaminated though diagnostic procedures and rubber dam placement. Eight endodontic residents provided samples by streaking gloved fingers on nutrient agar plates. Results showed no statistically significant difference between counts from new boxes versus nearly empty boxes (n = 32, p < 0.6216). Gloves after rubber dam placement yielded a mean colony count of 158 versus a 1.5 mean of fresh gloves (n = 64, p < 0.0001). These results suggest that the use of new gloves before opening a tooth for endodontic therapy may be warranted.
Microbial Contamination of Endodontic Files Received from the Manufacturer
Todd P. Roth, DMD, Scott I. Whitney, DDS, Stephen G. Walker, BSc MSc, PhD, Seymour Friedman, DDS
This study was conducted to test the sterility of new unused endodontic files received from manufacturers. Fifteen types of hand and rotary files from five manufacturers were tested. Positive microbial cultures were obtained from 13% of the 150 files tested. Autoclaved files were intentionally contaminated with bacterial species recovered from the positive cultures to evaluate a chairside sterilization method. Immersion of contaminated files in 5.25% sodium hypochlorite for five minutes sterilized the files. The results of this study indicate that endodontic files should be sterilized before clinical use. It is also suggested that manufacturers list the sterility state of their endodontic files on their packaging.
A Comparison of the Antimicrobial Efficacy of NaOCl/Biopure MTAD versus NaOCl/EDTA against Enterococcus faecalis
Patricia Kho, DDS, J. Craig Baumgartner, DDS, PhD
The purpose of this investigation was to compare the antimicrobial efficacy of irrigating with 1.3% NaOCl/Biopure MTAD versus irrigation with 5.25% NaOCl/15% EDTA in the apical 5 mm of roots infected with Enterococcus faecalis. Bilaterally matched human teeth were sterilized and inoculated with E. faecalis. After chemomechanical root canal preparation, the root-ends were resected and pulverized in liquid nitrogen to expose E. faecalis in dentinal tubules or other recesses away from the main root canal system. The number of colony forming units (CFU) of E. faecalis per mg was determined from the pulverized root-ends. No significant differences were seen (t = 0.70, p = 0.495) between the number of colony forming units of E. faecalis for teeth irrigated with 5.25% NaOCl/15% EDTA (mean 131 ± 291 CFU/mg) versus those teeth irrigated with 1.3% NaOCl/Biopure MTAD (mean 187 ± 237 CFU/mg). This study demonstrated that there is no difference in antimicrobial efficacy for irrigation with 5.25% NaOCl/15% EDTA versus irrigation with 1.3% NaOCl/Biopure MTAD in the apical 5 mm of roots infected with E. faecalis.
Comparison of the Intraosseous Biocompatibility of AH Plus, EndoREZ, and Epiphany Root Canal Sealers
Cássio J.A. Sousa, DDS, MSD, PhD, Cristiana R.M. Montes, DDS, Elizeu A. Pascon, DDS, MSD, PhD, Adriano M. Loyola, DDS, MSD, PhD, Marco A. Versiani, DDS, MSD
To evaluate the intraosseous biocompatibility of AH Plus, EndoREZ, and Epiphany root canal sealers as recommended by the Technical Report #9 of the Fédération Dentaire Internationale (FDI). Thirty guinea pigs, 10 for each material, divided into experimental periods of 4 and 12 weeks, received one implant on each side of the lower jaw symphysis. At the end of the observation periods, the animals were killed and the specimens prepared for routine histological examination. After analyzing both periods, the inflammatory tissue reaction to EndoREZ was considered severe. In the AH Plus group, the reaction changed from severe to moderate, while it was observed biological compatibility to Epiphany with bone formation and none to slight inflammatory reaction. It was concluded that Epiphany root canal sealer was the only material that presented intraosseous biocompatibility within the two analyzed periods.
Effect of Smear Layer and Chlorhexidine Treatment on the Adhesion of Enterococcus faecalis to Bovine Dentin
Seung-Eun Yang, DDS, MSc, Jeong-Heon Cha, PhD, Eui-Seong Kim, DDS, PhD, Kee-Yeon Kum, DDS, PhD, Chang-Young Lee, DDS, PhD, Il-Young Jung, DDS, PhD
The aim of this in vitro study was to determine the effects of a smear layer and chlorhexidine (CHX) treatment on the adhesion of Enterococcus faecalis to bovine dentin. Forty dentin blocks from bovine incisors were prepared and randomly divided into four groups of 10 each. The blocks in group 1 were placed in sterile saline for 5 minutes, while those in group 2 were treated with 17% EDTA for 5 minutes. The blocks in group 3 were placed in 2% CHX for 7 days. The blocks in group 4 were treated with 17% EDTA for 5 minutes, and then placed in 2% CHX for 7 days. All the blocks were immersed in a suspension of E. faecalis for 3 hours. The bacteria adhering to the dentin surface were counted by examination using a scanning electron microscope. The most significant amount of bacteria was retained on the samples from group 1 (p < 0.05) and the smallest amount of bacteria adhered to the samples from group 4. These results suggest that a smear layer enhances the adherence of E. faecalis to the dentin, and CHX is effective in reducing the adherence of microorganisms.
Comparative Evaluation of Three Nickel-Titanium Instrumentation Systems in Human Teeth Using Computed Tomography
M. Ozgur Uyanik, DDS, PhD, Zafer C. Cehreli, DDS, PhD, Burce Ozgen Mocan, MD, PhD, Fugen Tasman Dagli, DDS, PhD
This study investigated several parameters of root canal preparation with three different rotary NiTi systems: Hero Shaper, ProTaper, and RaCe. The parameters evaluated were: changes in root canal volume and cross-sectional area, canal transportation, and working time. Curved, mesial molar roots were scanned in a computed tomography (CT) unit before and after instrumentation. Cross-sectional views of each canal were obtained at 1 mm intervals. Postinstrumentation volume and cross-sectional area of root canals and the extent of transportation were calculated using image analysis software and, thereafter, subjected to statistical analysis. ProTaper removed significantly more dentin than Hero Shaper (p < 0.05). Instrumentation increased the cross-sectional area at all cutplanes, while the difference between test groups was not significant (p > 0.05). RaCe files significantly transported the canals at the coronal level (p < 0.05). There was no difference between any rotary systems in regards to working time.
In Vitro Assessment of a Gel Base Containing 2% Chlorhexidine as a Sodium Perborate’s Vehicle for Intracoronal Bleaching of Discolored Teeth
Daniel Pinto de Oliveira, DDS, MSc, Brenda Paula Figueiredo de Almeida Gomes, DDS, MSc, PhD, Alexandre Augusto Zaia, DDS, MSc, PhD, Francisco José de Souza-Filho, DDS, MSc, PhD, Caio Cezar Randi Ferraz, DDS, MSc, PhD
The purpose of this study was to assess a gel base containing 2% chlorhexidine (CHX) as a vehicle to be mixed with sodium perborate for intracoronal bleaching of discolored teeth, comparing its bleaching efficacy to sodium perborate mixed with other vehicles; 37% carbamide peroxide and 30% hydrogen peroxide. There were 110 fresh bovine incisors artificially stained using whole blood. The samples were divided into 11 groups and the intracoronal bleaching was performed using the “walking bleach technique”. The bleaching agents were replaced three times at 7-day intervals. Using digital photos and a shade guide created for bovine teeth, the samples were evaluated at day 0, 7, 14, 21, and 28. On evaluation day, the photos were examined by three endodontists giving scores from 1 to 5 based on the shade guide created. Data were analyzed statistically by Kruskall-Wallis test. After 28 days, all evaluated teeth received scores that were statistically similar. Groups that used sodium perborate and a liquid vehicle bleached faster than those that used a gel based vehicle. The CHX gel allowed dissociation for the bleaching agent. The 2% CHX gel exhibited a good potential for use as a vehicle for sodium perborate or as a complement for carbamide peroxide.
SEM Observations and Differential Scanning Calorimetric Studies of New and Sterilized Nickel-Titanium Rotary Endodontic Instruments
Georgia B. Alexandrou, Konstantinos Chrissafis, Leonidas P. Vasiliadis, Eleni Pavlidou, E.K. Polychroniadis
Scanning electron microscopy (SEM) and differential scanning calorimetric (DSC) studies were utilized to investigate surface and microstructure of two brands of rotary nickel-titanium (NiTi) endodontic instruments, in the as-received condition and after subjection to 1, 6, and 11 sterilization cycles. A total of 66 ProFile (n = 33) and Flexmaster (n = 33) files were examined. SEM observations indicated the presence of surface imperfections and adherent material in all new and sterilized instruments and an increase in surface roughness of the instruments that underwent multiple sterilizations. DSC measurements showed that the specimens of both brands, in the as-received condition and after 11 sterilizations, were completely austenite in the oral environment temperature, suggesting that they are capable of superelastic behavior in appropriate clinical conditions.
Delivery of Calcium Hydroxide: Comparison of Four Filling Techniques
Richard M. Simcock, DDS, M. Lamar Hicks, DDS, MS
This study compared the weight and radiographic appearance of Ca(OH)2 delivered into standardized, minimally and fully prepared canals using (a) an injection system, (b) an endodontic Flex-O file rotated counter-clockwise, (c) a lentulo spiral, and (d) a .04 rotary NiTi file rotated in reverse. Two extracted human second mandibular premolars with single canals were prepared to an MAF #25 or an MAF #40. A weight measurement and radiograph were made for each filling. Three independent examiners evaluated the radiographs. Regardless of technique, only about 45% of the optimal weight of Ca(OH)2 was delivered into the minimally prepared canal. Radiographically the filling quality was only 1 to 2 (10 scale). In contrast, all delivery techniques delivered near optimal weight of Ca(OH)2 in the completely prepared canal with a radiographic filling quality of 8.8 to 9.3. The results indicate that complete instrumentation is needed to obtain near optimal delivery of Ca(OH)2.
A Comparison of Thermal Properties Between Gutta-Percha and a Synthetic Polymer Based Root Canal Filling Material (Resilon)
Marcus R. Miner, DDS, David W. Berzins, PhD, James K. Bahcall, DMD, MS
A new polymer-based obturating material, Resilon, has been developed but there have been no studies identifying its thermal properties. The purpose of this study was to compare the melting point, specific heat, enthalpy change with melting and heat transfer between gutta-percha (GP) and Resilon (R). The first three tests were determined using a differential scanning calorimeter and the heat transfer test was determined using a split-tooth model. Results show no significant difference (t test, p > 0.05) between gutta-percha and Resilon for the melting point temperature (GP: 60.01°C; R: 60.57°C). There was a significant difference (t test, p < 0.05) in specific heat capacity (GP: 0.94 J/g °C, R: 1.15 J/g °C) and endothermic enthalpy change (GP: 10.88 J/g, R: 25.20 J/g) between the two materials. The heat transfer test showed a significant difference (Mann-Whitney, p < 0.05) in temperature increase between gutta-percha and Resilon within 3 mm of the heat source.
Endodontic Management of a Maxillary First Molar with a Single Root and a Single Canal Diagnosed with the Aid of Spiral CT: A Case Report
Velayutham Gopikrishna, MDS, Narayanan Bhargavi, BDS, Deivanayagam Kandaswamy, MDS
The aim of this article is to present an endodontically managed maxillary first molar with an unusual morphology of a single root and a single canal, which has not been reported in the literature so far. An accurate assessment of this unusual morphology was made with the help of a Spiral computed tomography. This report extends the range of known possible anatomical variations to include teeth with lesser number of roots and canals. This report also highlights the role of Spiral computed tomography as an objective method to confirm the three-dimensional anatomy of teeth.
Aspergillus mycetoma of the Maxillary Sinus Secondary to Overfilling of a Root Canal
Luciano Giardino, MD, DDS, Francesco Pontieri, MD, Enrico Savoldi, MD, DDS, Federico Tallarigo, MD
In nonimmunocompromised patients aspergillosis of the paranasal sinuses is a relatively rare disease. Root canal treated teeth with overextension of the root canal sealer or solid materials such as gutta-percha or silver cones into the sinus might be the main etiological factor for aspergillosis of the maxillary sinus in healthy patients. Root-filling materials based zinc oxide-eugenol is considered to be a growth factor for aspergillus. Aspergillus fumigatus needs heavy metals such as zinc oxide for proliferation and metabolism. Prognostic and histological studies showed that instrumentation and obturation should not extend beyond the apical foramen. When the sealer and/or gutta-percha is extruded within the sinus, this produce an inflammatory reaction and then Aspergillus growth. We report one case of healthy 60-yr-old male with overextension of root canal sealer in maxillary sinus. After surgical procedure, microscopic examination revealed aspergillosis. Overextension into the maxillary sinus with root canal cements has to be avoided.