Use of Biomaterials in Periradicular Surgery: A Case Report
Amauri Favieri, DDS, MSc, PhD, Luís Claudio Campos, DDS, MSc, Viviane Holmes Burity, DDS, Maurício Santa Cecília, DDS, MSc, PhD, Ernani Da Costa Abad, DDS, PhD
This article reports a case of periradicular surgery in which biomaterials, such as mineral trioxide aggregate (MTA), human lyophilized bone, and calcium sulfate, were used. A 21-year-old female patient was referred to our endodontic clinic as a result of recurrent episodes of acute exacerbation of a chronic process involving the maxillary left lateral incisor. There was complete destruction of the buccal bone plate at the apical third, leaving this portion of the root exposed to the oral cavity. After conventional root canal therapy carried out under special tooth isolation conditions, apicoectomy was performed, and a root-end cavity was prepared and restored with MTA as a retrofilling material. Because of the exposure of the root-end resection to the mouth, osteoinductive and osteoconductive materials (human lyophilized bone and calcium sulfate, and calcium sulfate alone, respectively) were used, with the goals of modeling the lost bone structure, preventing invasion of the oral epithelium, and avoiding the occurrence of secondary infection. Two years after the periradicular surgery, there were no clinical or radiographic signs suggestive of treatment failure, but instead the patient’s follow-up has shown that the case management has been successful as indicated by lesion regression and periodontal repair. On the basis of the review of literature and the clinical-radiographic outcomes hereby presented, it might be concluded that (1) large bone destructions caused by periradicular lesions might and should be filled with recognizably effective bone-replacing materials during regenerative tissue process. MTA, human lyophilized bone, and calcium sulfate seemed to have an important role in alveolar bone induction, remodeling, and repair. (2) Because of its characteristics of promoting excellent marginal sealing and stimulating osteoblastic adherence to the retrofilling surface, MTA has been considered as the retrofilling material of choice.
The Effectiveness of Manual and Mechanical Instrumentation for the Retreatment of Three Different Root Canal Filling Materials
Francesco Somma, MD, DDS, Giuseppe Cammarota, DDS, Gianluca Plotino, DDS, Nicola M. Grande, DDS, Cornelis H. Pameijer, DMD, DSc, PhD
The aim of this study was to compare the effectiveness of the Mtwo R (Sweden & Martina, Padova, Italy), ProTaper retreatment files (Dentsply-Maillefer, Ballaigues, Switzerland), and a Hedström manual technique in the removal of three different filling materials (gutta-percha, Resilon [Resilon Research LLC, Madison, CT], and EndoRez [Ultradent Products Inc, South Jordan, UT]) during retreatment. Ninety single-rooted straight premolars were instrumented and randomly divided into 9 groups of 10 teeth each (n = 10) with regards to filling material and instrument used. For all roots, the following data were recorded: procedural errors, time of retreatment, apically extruded material, canal wall cleanliness through optical stereomicroscopy (OSM), and scanning electron microscopy (SEM). A linear regression analysis and three logistic regression analyses were performed to assess the level of significance set at p = 0.05. The results indicated that the overall regression models were statistically significant. The Mtwo R, ProTaper retreatment files, and Resilon filling material had a positive impact in reducing the time for retreatment. Both ProTaper retreatment files and Mtwo R showed a greater extrusion of debris. For both OSM and SEM logistic regression models, the root canal apical third had the greatest impact on the score values. EndoRez filling material resulted in cleaner root canal walls using OSM analysis, whereas Resilon filling material and both engine-driven NiTi rotary techniques resulted in less clean root canal walls according to SEM analysis. In conclusion, all instruments left remnants of filling material and debris on the root canal walls irrespective of the root filling material used. Both the engine-driven NiTi rotary systems proved to be safe and fast devices for the removal of endodontic filling material.
Preoperative Predictors of Number of Root Canals Clinically Detected in Maxillary Molars: A PennEndo Database Study
Mian Iqbal, DMD, MS, Eric Fillmore, DDS
The purpose of this investigation was to evaluate the concomitant influence of several variables on the number of root canals clinically detected in maxillary molars. The study used multiple logistic regression analysis on data from 1328 patients, aged 6–82 years, who received nonsurgical root canal treatment on maxillary molars at the University of Pennsylvania from 2000–2006. The number of canals was used as the dependent variable, whereas tooth type, age, caries, referral source, restoration, and pulpal and periapical diagnosis were used as independent variables. One was 0.98 times less likely to detect more canals when the age increased by 1 year. Similarly, one was 1.4 times more likely to detect canals in teeth with caries than teeth without caries. When these independent variables were controlled, only age of the individual was significantly related to number of root canals detected.
Effect of Dynamic Loading on the Integrity of the Interface between Root Canal and Obturation Materials
Dan Bishop, DDS, MS, PhD, Jason Griggs, PhD, Jianing He, DMD, PhD
The purpose of this study was to evaluate the effect of occlusal load on the integrity of root canal obturation. Maxillary anterior teeth were cleaned, shaped, and obturated with either gutta-percha (GP)/AH Plus or Resilon/Epiphany. Afterwards, teeth were placed under 100 N force at 2 Hz for 22 hours in a 37°C water bath. Teeth were sectioned and examined for disruption in the integrity of the obturation by using optical microscopy. The length of the separation between the obturation and the root canal walls was measured and compared statistically. GP and Resilon obturated canals subjected to occlusal load displayed significantly greater interface disruption compared with unloaded controls (p < .05). The results indicate that occlusal load generates separation forces on the obturation interface that might compromise the sealing ability of the obturation.
Proliferative Periostitis: A Case Report
Vahid Zand, DMD, MSc, Mehrdad Lotfi, DMD, MSc, Sepideh Vosoughhosseini, DMD, MSc
Proliferative periostitis of Garré represents a periosteal reaction to the presence of infection or other irritants. This can be odontogenic or nonodontogenic. This is a case report of an odontogenic periostitis resulting from endodontic origin. It was successfully treated by nonsurgical root canal therapy without using antibiotic therapy during the treatment of this case.
Transforming Growth Factor β2 Regulates Growth and Differentiation of Pulp Cells via ALK5/Smad2/3
Tseng-Fang Tai, DDS, MS, Chiu-Po Chan, DDS, Chiu-Chun Lin, DDS, MS, Lin-I Chen, DDS, Jiiang-Huei Jeng, DDS, Mei-Chi Chang, MS, PhD
Transforming growth factor β (TGF-β) may regulate the biological activities of dental pulp cells. We found that human dental pulp cells expressed TGF-β1, TGF-β2, and a little amount of TGF-β3 messenger RNA (mRNA). The exposure of pulp cells to TGF-β2 induced the phosphorylation of Smad2/3, Smad1/5/8, and extracellular regulated-kinase 1/2 (ERK1/2) as observed by Western blotting. Exposure to TGF-β2 decreased the alkaline phosphatase (ALP) mRNA expression and enzyme activity. Pretreatment of pulp cells with SB431542 (an inhibitor of TGF-β ALK-4, ALK-5, and ALK-7 receptors) but not U0126 (a MEK1 inhibitor) prevented the inhibition of viable cell number, ALP activity, and mRNA expression by TGF-β2 in dental pulp cells. These results suggest that TGF-β may affect the growth and differentiation of dental pulp cells via an autocrine fashion by activation of the ALK/Smad2/3-signal transduction pathways. TGF-β2 possibly regulates the differentiation of pulp cell at specific stages synergistically with other factors.
In Vivo Generation of Dental Pulp-like Tissue by Using Dental Pulp Stem Cells, a Collagen Scaffold, and Dentin Matrix Protein 1 after Subcutaneous Transplantation in Mice
Rebecca S. Prescott, DDS, MS, Rajaa Alsanea, DDS, Mohamed I. Fayad, DDS, MS, PhD, Bradford R. Johnson, DDS, MHPE, Christopher S. Wenckus, DDS, Jianjun Hao, PhD, Asha S. John, MS, Anne George, PhD
The presence of a perforation is known to significantly compromise the outcome of endodontic treatment. One potential use of regenerative endodontic therapy might be the repair of root canal perforations. In addition to nutrients and systemic in situ interactions, the 3 main components believed to be essential for tissue regeneration are stem cells, scaffold, and growth factors. This study investigated the role of each component of the tissue engineering triad in the organization and differentiation of dental pulp stem cells (DPSCs) in a simulated furcal perforation site by using a mouse model. Collagen served as the scaffold, and dentin matrix protein 1 (DMP1) was the growth factor. Materials were placed in simulated perforation sites in dentin slices. Mineral trioxide aggregate was the control repair material. At 6 weeks, the animals were killed, and the perforation sites were evaluated by light microscopy and histologic staining. Organization of newly derived pulp tissue was seen in the group containing the triad of DPSCs, a collagen scaffold, and DMP1. The other 4 groups did not demonstrate any apparent tissue organization. Under the conditions of the present study, it might be concluded that the triad of DPSCs, a collagen scaffold, and DMP1 can induce an organized matrix formation similar to that of pulpal tissue, which might lead to hard tissue formation.
Effect of Dentin Thickness on Root Surface Temperature of Teeth Undergoing Ultrasonic Removal of Posts
Brooks B. Horan, DDS, MS, Patricia A. Tordik, DMD, Glen Imamura, DDS, MS, Gary G. Goodell, DDS, MS, MA
The purpose of this study was to measure root surface temperature changes on thin-rooted and thick-rooted teeth undergoing ultrasonic vibration of cemented posts, with and without irrigation. Twenty-four single canal teeth were decoronated, length standardized, instrumented, obturated, and cemented with prefabricated posts. The teeth were divided into thin-rooted or thick-rooted groups. Thermocouples were cemented to the external proximal root surfaces adjacent the post ends. The roots were then mounted in standardized plaster molds and placed in a temperature-controlled water bath. Posts were ultrasonically vibrated with and without irrigation, and external root temperatures were recorded from an initial 37°C baseline for a period of 4 minutes. The data were analyzed with the Student t test at α = .05. No significant differences were found in temperature change between the thin-rooted and thick-rooted groups, with or without irrigation. Linear regression and correlation analysis revealed no relationship between dentin thickness and temperature change.
Terrein Reduces Pulpal Inflammation in Human Dental Pulp Cells
Jung-Chang Lee, PhD, Mi-Kyung Yu, DDS, PhD, Rin Lee, DDS, PhD, Young-Hee Lee, PhD, Jae-Gyu Jeon, DDS, PhD, Min-Ho Lee, PhD, Eun-Chung Jhee, PhD, Ick-Dong Yoo, PhD, Ho-Keun Yi, PhD
Terrein is a bioactive fungal metabolite whose anti-inflammatory properties are virtually unknown. The purpose of this study was to determine the effects of terrein on lipopolysaccharide (LPS)-induced expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in human dental pulp cells and to determine the mechanism of the observed effects. The LPS-induced expression of ICAM-1 and VCAM-1 was inhibited by terrein in both a time- and dose-dependent manner. LPS-stimulated translocation of nuclear factor kappa B (NF-κB) into the nucleus, which was blocked by inhibitors of amino kinase terminal (AKT, LY294002), extracellular signal regulated kinase 1/2 (ERK , PD98059), p38 (SB203580), and c-jun NH2-terminal kinase (JNK, SP600125) or terrein. In addition, these inhibitors and terrein also reduced the level of ICAM-1 and VCAM-1 expression in LPS-induced inflammation of pulp cells. Terrein suppressed NF-κB activation by blocking the activation of Akt. These results strongly suggest the potential role of terrein as an anti-inflammatory modulator in pulpal inflammation.
Impact of Er,Cr:YSGG Laser Therapy on the Cleanliness of the Root Canal Walls of Primary Teeth
Flavio Soares, DDS, MS, Claudio H. Varella, DDS, MS, Roberta Pileggi, DDS, MS, Abi Adewumi, BDS, FDSRCS, MPaed Dent RCS, Marcio Guelmann, DDS
Root canal therapy might be required for primary teeth displaying signs of pulpal inflammation or necrosis. Cleaning and shaping followed by obturation of the canal space with a resorbable paste have been widely performed with remarkable clinical success. However, lengthy endodontic procedures might be contraindicated when treating certain pediatric patients. The aim of this study was to compare the cleanliness of the root canal walls of primary teeth and the time required for the completion of the cleaning and shaping procedures performed by the Er,Cr:YSGG laser, manual or rotary instrumentation techniques. Thirty-five extracted, single-rooted, primary teeth were divided into 4 groups: I, canals were instrumented with Profile .04 rotary instruments to a master apical file size #35; II, the laser was used (parameters: 1.50 W, 20 pps, 30% water and 50% air) with a Z3 laser tip (0.32-mm diameter); III, canals were instrumented with stainless steel K-files; and IV, no instrumentation was performed (control). The teeth were split in 2 halves and prepared for scanning electron microscopy analysis. Images from the coronal, middle, and apical thirds of the roots were analyzed independently by 2 calibrated, blinded evaluators. Statistical analysis revealed significant differences among the groups (Kruskal-Wallis, P = .0001). The techniques were not capable of providing completely clean canals. Treatment with Er,Cr:YSGG laser provided similar cleanliness when compared with rotary instrumentation technique and was superior to manual instrumentation. The laser technique required less time for completion of the cleaning and shaping procedures when compared with both rotary or hand instrumentation.
In Vitro Study to Compare the Coronal Microleakage of Tempit UltraF, Tempit, IRM, and Cavit by Using the Fluid Transport Model
Susan O. Koagel, DMD, Pete Mines, DDS, Michael Apicella, DDS, Mark Sweet, DDS>
An adequate coronal seal is critical for the success of root canal therapy. The purpose of this study was to assess and compare the coronal microleakage of 4 temporary filling materials used to seal the access cavity in root canal treated teeth. Standardized access cavities were prepared in 55 extracted human, single canal teeth. They were instrumented by using a crown-down method to a size 45 file. The smear layer was removed with a 1-minute soak with 17% ethylenediaminetetraacetic acid followed by a 10-minute soak with 5.25% NaOCl and dried with paper points. All roots were obturated with gutta-percha and AH Plus sealer by using the continuous wave of condensation technique. The teeth were randomly divided into 4 groups of 10 teeth, with the remaining teeth serving as positive and negative controls. The access openings of the teeth in the experimental groups were filled with 4 mm of Cavit, IRM, Tempit, or Tempit-Ultra-F. All teeth were stored in 100% humidity at 37° for 10 days, allowing sealer to set before testing. After thermocycling for 500 cycles (5°C–55°C), microleakage was measured by using the fluid transport model at 10 psi. All materials tested leaked. Kruskal-Wallis and Mann-Whitney U analysis indicated significantly less leakage (P < .05) with Tempit UltraF compared with Cavit and IRM. There were no statistically significant differences between Tempit Ultra-F and Tempit or between Cavit, IRM, and Tempit.
Nonvital Tooth Bleaching: A Review of the Literature and Clinical Procedures
Gianluca Plotino, DDS, Laura Buono, DDS, Nicola M. Grande, DDS, Cornelis H. Pameijer, DMD, DSc, PhD, Francesco Somma, MD, DDS
Tooth discoloration varies in etiology, appearance, localization, severity, and adhesion to tooth structure. It can be defined as being extrinsic or intrinsic on the basis of localization and etiology. In this review of the literature, various causes of tooth discoloration, different bleaching materials, and their applications to endodontically treated teeth have been described. In the walking bleach technique the root filling should be completed first, and a cervical seal must be established. The bleaching agent should be changed every 3–7 days. The thermocatalytic technique involves placement of a bleaching agent in the pulp chamber followed by heat application. At the end of each visit the bleaching agent is left in the tooth so that it can function as a walking bleach until the next visit. External bleaching of endodontically treated teeth with an in-office technique requires a high concentration gel. It might be a supplement to the walking bleach technique, if the results are not satisfactory after 3–4 visits. These treatments require a bonded temporary filling or a bonded resin composite to seal the access cavity. There is a deficiency of evidence-based science in the literature that addresses the prognosis of bleached nonvital teeth. Therefore, it is important to always be aware of the possible complications and risks that are associated with the different bleaching techniques.
Traumatic Bone Cyst Suggestive of Large Apical Periodontitis
Cleomar Donizeth Rodrigues, DDS, MSc, Carlos Estrela, DDS, MSc, PhD
This case report shows the importance of establishing the correct diagnosis to provide the appropriate treatment options The traumatic bone cyst is a pseudocyst, usually asymptomatic and found by a routine radiographic examination. Unicystic radiolucency is almost always observed, which can involve the periradicular area of teeth, simulating an inflammatory lesion of endodontic origin. Differential diagnosis should include other pathologies, such as odontogenic keratocyst, central giant cell granuloma, and unicystic ameloblastoma. Its etiology and pathogenesis are not yet definitely established. In the present study, after review of the medical and dental histories and clinical and radiographic examination of teeth #24-27 (pulpal vitality test showed positive), the primary diagnosis was traumatic bone cyst. The planning was excisional biopsy. After surgical exploration, only one small blood clot was observed in the intraosseous socket, which was carefully curetted and filled with blood. A clinical and radiographic examination after 6 months showed apical formation and pulpal vitality preserved.
A Prospective, Randomized, Double-blind Comparison of Articaine and Lidocaine for Maxillary Infiltrations
Grace Evans, DMD, MS, John Nusstein, DDS, MS, Melissa Drum, DDS, MS, Al Reader, DDS, MS, Mike Beck, DDS, MA
The purpose of this prospective, randomized, double-blind crossover study was to evaluate the anesthetic efficacy of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine in maxillary lateral incisors and first molars. Eighty subjects randomly received, in a double-blind manner, maxillary lateral incisor and first molar infiltrations of one cartridge of 4% articaine with 1:100,000 epinephrine or 2% lidocaine with 1:100,000 epinephrine at two separate appointments spaced at least 1 week apart. In maxillary lateral incisors, articaine exhibited a significantly higher anesthetic success rate of 88% when compared with a 62% success rate with lidocaine. In maxillary first molars, articaine had a similar success rate to lidocaine (78% vs 73%), and there was no significant difference between the two solutions. In conclusion, a maxillary infiltration of 4% articaine with 1:100,000 epinephrine statistically improved anesthetic success when compared with 2% lidocaine with 1:100,000 epinephrine in the lateral incisor but not in the first molar.
Comparison of Regrowth of Enterococcus faecalis in Dentinal Tubules after Sealing with Gutta-Percha or Resilon
Su-Jung Shin, DDS, MS, Sang-Wook Jee, DDS, MSD, Jin-Seon Song, BDS, MS, FRACDS, Il-Young Jung, DDS, MSD, PhD, Jeong-Heon Cha, PhD, Euiseong Kim, DDS, MSD, PhD
The objective of this study was to compare the sealing ability of gutta-percha (GP) and Resilon on Enterococcus faecalis in the dentinal tubules. Bovine root dentin blocks were infected and filled with GP alone, GP with zinc oxide–eugenol sealer, GP with resin sealer, or Resilon with resin sealer. The blocks were incubated in Brain-Heart Infusion agar plates up to 4 weeks, after which dentin chips were collected from the canal walls. The optical density of the culture medium containing the dentin chips was measured and analyzed statistically. Our results indicated that none of the filling materials were able to prevent the regrowth of E. faecalis completely. Although we noted no significant differences in bacterial counts among those groups filled with sealers, different patterns of change in bacterial counts were noted regarding time points. Filling with Resilon and a resin-based sealer induced a significant reduction in the bacterial counts over time (P < .05).
An In Vitro Study to Assess the Setting and Surface Crazing of Conventional Glass Ionomer Cement when Layered over Partially Set Mineral Trioxide Aggregate
Suma Ballal, MDS, Nagendrababu Venkateshbabu, BDS, Suresh Nandini, MDS, Deivanayagam Kandaswamy, MDS
The aim of our study was to assess the setting time and surface crazing of glass ionomer cement when layered over partially set mineral trioxide aggregate (MTA). To assess setting time, 40 hollow, cylindrical stainless steel molds were taken and equally divided into 4 groups. In groups I, II, and III glass ionomer cement was layered over partially setting MTA at 45 minutes, 4 hours, and 3 days, respectively. Group IV was used as a control. An additional 50 specimens were prepared for assessment of surface crazing. Twenty specimens (groups I and II) were prepared to study normal and desiccated patterns of conventional glass ionomer cement, respectively. Thirty specimens (groups III, IV, and V) were prepared by layering glass ionomer cement over partially set MTA at various time intervals. All the specimens were stained with red ink and analyzed for craze lines by light microscopy. From our study, it was observed that there was no statistical difference in setting time of glass ionomer cement when layered over partially set MTA in comparison to that of the control group. No craze lines were observed in those specimens (groups III, IV, and V) when viewed under staining and light microscopy. It could be concluded that conventional glass ionomer cement might be layered over partially set MTA after 45 minutes and could be used for single visit procedures.
The Shaping Effect of the Combination of Two Rotary Nickel-Titanium Instruments in Simulated S-Shaped Canals
Lan Zhang, MD, Hong-xia Luo, DDS, MD, Xue-dong Zhou, DDS, PhD, Hong Tan, DDS, Ding-ming Huang, DDS, PhD
This study aimed to analyze the ability of ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) combined with Hero642 (MicroMega, Besancon, France) to shape the simulated S-shaped canals. Thirty simulated canals with double curvatures, 30° coronally and 20° apically, were randomly divided into three groups and prepared with different instruments: ProTaper in group 1, Hero642 in group 2, and a combination of ProTaper and Hero642 in group 3. All canals were scanned pre- and postoperatively. Each postinstrumentation image was superimposed with the preoperative one in a computer. The amount of material removed from canal wall after every instrument was measured at 14 points. Statistical analysis was performed by using an analysis of variance test at α = 0.05. Canals prepared with rotary ProTaper were straightened progressively after the use of F1, and great transportation was created. Hero642 and the combination instruments maintained the original shape of canal with a little transportation. However, the taper of canals prepared with Hero642 was relatively poor.
Comparative Study of the Variability of 0.06 Tapered Rotary Endodontic Files to Current Taper Standards
Garth W. Hatch, DDS, Steven Roberts, DDS, Anthony P. Joyce, DDS, Royce Runner, James C. McPherson III, PhD
This study compared the taper variation among Profile, Guidance, and EndoSequence 0.06 tapered rotary files to current standards. Fifteen files of sizes 35, 40, and 45 from each manufacturer were evaluated for a total of 135 files. A digital image of the first 4 mm of each file was captured with light microscope at 22×, calibrated for 0.001-mm accuracy, and analyzed. The diameter of each file was measured at 1 and 4 mm, and the taper was calculated. Of the 3 file systems, 100% of the Profile files, 97.8% of the Guidance files, and 86.7% of the EndoSequence files fell within ±0.02 taper. All file systems demonstrated variability within their groups. A series of χ2 analyses indicated that manufacturers tend to produce Guidance and Profile tapers slightly under the ideal 0.06 taper (P < .05). The tapers of EndoSequence files were just as likely to be over or under the advertised 0.06 taper (P > .05).
Histomorphometric Study of the Root Apex of Mandibular Premolar Teeth: An Attempt to Correlate Working Length Measured with Electronic and Radiograph Methods to Various Anatomic Positions in the Apical Portion of the Canal
Ehab E. Hassanien, PhD, Abeer Hashem, PhD, Henry Chalfin, DDS
One aim of this study was to attempt to relate the position of the cementodentinal junction (CDJ) and the apical constriction to that of the apical foramen in mandibular premolars, as well as to measure the canal diameter at these various points. Another aim was to evaluate how electronic working length determination by Root ZX and radiographic method of working length determination correlated to the location of these various positions. The results showed that CDJ was detected at average distance of 0.3 mm from apical foramen with average canal diameter of 0.32 mm, whereas the apical constriction was detected at average distance from apical foramen of 1.2 mm with canal diameter of 0.22 mm. There was a statistically significant difference between file-tip position from apical foramen in group I working length measured by Root ZX and group II working length measured radiographically. Also this significant difference was found between file-tip position in both groups and CDJ and apical constriction. The average canal diameter at 0.5, 1, and 1.5 mm from apical foramen was 0.33 ± 0.11, 0.28 ± 0.06, and 25 ± 0.05 mm, respectively.
The Effect of Pulp Obliteration on Pulpal Vitality of Orthodontically Intruded Traumatized Teeth
Oskar Bauss, PhD, Johannes Röhling, DMD, Alexander Rahman, DMD, Stavros Kiliaridis, PhD
Limited information exists on the impact of pulp obliteration on pulpal vitality of orthodontically treated traumatized teeth. Pulpal condition was examined in 269 traumatized maxillary incisors after orthodontic intrusion (OT group) and in 193 traumatized maxillary incisors without subsequent orthodontic treatment (C group). According to the degree of initial pulp obliteration, the teeth were divided into three categories: teeth without, teeth with partial, and teeth with total pulp obliteration. Teeth in the OT group revealed a significantly higher rate of pulp necrosis than teeth in the C group (p < 0.001). In addition, teeth in the OT group with total pulp obliteration showed a significantly higher rate of pulp necrosis than teeth without (p < 0.001) or only partial pulp obliteration (p = 0.025). The results indicate that traumatized teeth with total pulp obliteration have a higher susceptibility to pulpal complications during orthodontic intrusion than traumatized teeth without or only partial pulp obliteration.
Similar Glucose Leakage Pattern on Smear-covered, EDTA-treated and BioPure MTAD–treated Dentin
Gustavo De-Deus, DDS, MS, Juliana Soares, DDS, Fernanda Leal, DDS, Aderval S. Luna, PhD, Sandra Fidel, DDS, MS, PhD, Rivail Antonio Sergio Fidel, DDS, MS, PhD
This study assessed the effect of BioPure MTAD on the sealing ability on the basis of the filtration rate of glucose along the root fillings. Both 17% ethylenediaminetetraacetic acid (EDTA) and smear-covered dentin were used as reference patterns to compare the results. Sixty-four human upper incisors were prepared with different irrigation protocols (n = 18): G1, NaOCl; G2, NaOCl + EDTA; and G3, NaOCl + BioPure MTAD. The teeth were obturated and then prepared in a double-chamber apparatus to evaluate the glucose leakage along the root fillings. The amount of glucose leakage was quantified with spectrophotometry at 7, 14, 21, 28, 35, 42, 49, and 56 days. Leakage existed in every sample and was variable in all of the experimental groups, and Kruskal-Wallis H test results showed that there were no significant differences among the experimental groups (P > .05). The smear-covered dentin did not allow more glucose leakage than EDTA-treated and BioPure MTAD–treated dentin.
Effect of Lowering the pH of Sodium Hypochlorite on Dissolving Tissue in Vitro
Chad E. Christensen, DMD, Sandre F. McNeal, MPH, Paul Eleazer, DDS, MS
Sodium hypochlorite (NaOCl), a common antimicrobial and tissue-dissolving irrigant, comes from the manufacturer at pH 12. When the pH is lowered, NaOCl becomes more antimicrobial. The aim of this study was to examine what effect lowering the pH has on the property of tissue dissolution. Seven groups were tested for dissolving porcine muscle tissue at varying pH, concentrations, and times. When groups were examined solely by pH, there was no significant difference between the pH 12 and 9 groups, but a statistically significant level was found between pH 12 and 9 versus the pH 6 groups (P < .05). Higher concentrations and greater time periods all led to greater amounts of tissue dissolution.