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Introduction The purpose of this retrospective study was to determine the clinical and radiographic outcomes of root-end microsurgery in a postgraduate program in endodontics using modern techniques and calcium silicate–based root-end filling materials (ProRoot MTA; Dentsply International, Johnson City, TN, and EndoSequence Root Repair Material [ERRM]; Brasseler USA, Savannah, GA) and to identify any potential prognostic factors that may have affected healing outcomes. Methods Clinical records and periapical radiographs were collected from patients who had undergone endodontic microsurgery between 2007 and 2018 in a postgraduate endodontic clinic with a minimum follow-up interval of 6 months. Either ProRoot MTA or ERRM was used as the root-end filling material. Outcomes were categorized into healed, healing, and nonhealing based on clinical and radiographic findings. Healed and healing cases were pooled and considered as successes, whereas nonhealing cases were considered as failures. Results A total of 129 patients with 142 teeth were included in the final analysis. Seventy-six cases were root-end filled with ProRoot MTA and 66 root-end filled with ERRM. The ProRoot MTA group had a success rate of 92.1%, and the ERRM group had a success rate of 92.4% with no significant difference between the groups (P > .05). Vertical root fracture was found to be the predominant cause of failure. No patient- or treatment-related factor was identified to have any significant impact on healing. Conclusions High overall success can be achieved in a postgraduate endodontic program when either ProRoot MTA or ERRM is used as the root-end filling material.

Introduction NeoMTA Plus (Avalon Biomed Inc, Bradenton, FL) is a tricalcium silicate material similar to the first mineral trioxide aggregate product, ProRoot MTA (Dentsply Sirona, York, PA), but with improvements such as decreased setting time, increased ion release, increased water sorption, and nonstaining radiopacifiers. Quick-Set2 (Avalon Biomed Inc) is a newly formulated calcium aluminosilicate material that has a faster setting time and increased acid resistance and is nonstaining. The purpose of this study was to compare the healing of pulpal and periapical tissues in dogs after exposure to NeoMTA Plus and Quick-Set2 after pulpotomy and root-end surgery procedures. Methods Seventy-two teeth (36 for each procedure) in 6 beagle dogs received pulpotomy or root-end surgery using either NeoMTA Plus or Quick-Set2. The dogs were sacrificed at 90 days, and the teeth and surrounding tissues were prepared for histologic evaluation. Sixty teeth were evaluated and scored histologically (29 with pulpotomies and 31 with root-end resections). Specimens were scored for inflammation, quality and thickness of dentin bridging, pulp tissue response, cementum and periodontal ligament formation, and apical bone healing. Results Both materials displayed favorable healing at 90 days. The only significant difference was the quality of dentin bridge formation in pulpotomies using NeoMTA Plus compared with Quick-Set2. Conclusions Quick-Set2 and NeoMTA Plus had similar effects on inflammation, pulp response, periodontal ligament and cementum formation, and apical tissue healing in dogs. NeoMTA Plus had superior dentin bridge quality compared with Quick-Set2.

There have been many recent technical advances in modern endodontics that have the potential to affect treatment outcomes. Reports on treatment outcomes using contemporary techniques are relatively scarce, especially in the field of nonsurgical retreatment. The purpose of this study was to determine the success of nonsurgical root canal retreatment in molars using contemporary endodontic techniques.Sixty-three patients referred for retreatment in first molars were enrolled in the study. The retreatment procedures were performed by endodontic residents using a semistandardized treatment protocol. Patients were followed-up at 6, 12, and 24 months. Treatment outcomes were categorized into healed, healing, or nonhealing based on clinical and radiographic criteria. Healed and healing were considered as successes, and nonhealing was considered a failure. Outcomes were also evaluated using patient-centered criteria that included oral health-related quality of life scores and subjective chewing ability.Fifty-two of the 63 patients were available for final analysis. Five cases (9.6%) were determined to be nonhealing at the last follow-up with new or persistent periapical lesions. Thirty-seven (71.2%) patients had complete resolution of apical periodontitis, and the remaining 10 (19.2%) remained asymptomatic and showed radiographic evidence of healing. Oral health-related quality of life scores and chewing ability improved significantly over time (P .05), with the biggest increase observed within the first week of treatment completion.This study showed that endodontic retreatment using contemporary techniques significantly improved patients' quality of life and chewing ability over time, with a success rate of 90.4% after 2 years.

Introduction Calcium silicate–based sealers are known to have excellent sealing ability and bioactivities. They are typically recommended to be used in a single-cone (SC) technique. No studies have evaluated the effects of the thermoplastic obturation technique on the dentin interface of these sealers. The purpose of this study was to evaluate the push-out bond strengths of MTA Plus Sealer (Avalon Biomed Inc, Bradenton, FL) and EndoSequence BC Sealer (BC; Brasseler USA, Savannah, GA) when they were used in a thermoplastic technique. Methods Fifty single-rooted human extracted teeth were randomly divided into 5 groups (n = 10), instrumented, and obturated with the SC technique or continuous wave (CW) technique: group 1, BC-SC; group 2, BC-CW; group 3, MTA Plus–SC; group 4, MTA Plus–CW; and group 5, AH Plus (Dentsply DeTrey, Konstanz, Germany)–CW. The roots were sectioned into 1.0-mm-thick slices, and bond strengths were measured using a standardized push-out test. The mode of failure was determined by visual inspection under magnification. Results The MTA Plus–CW had statistically significant lower bond strengths than all other groups. The BC-SC group had statistically higher bond strengths than the MTA Plus–SC and AH Plus–CW groups. No significant differences were seen among the other groups. Modes of failure were predominately cohesive or mixed except for group 4 (ie, MTA Plus–CW) in which nearly half the specimens had no visible sealer. Conclusions BC and MTA Plus sealer showed favorable bond strengths when used in an SC technique. The CW obturation technique decreased the bond strengths of these sealers.

Introduction One of the important steps in root canal treatment is to create a well-sealed root canal system. EndoSequence BC Sealer (BC; Brasseler USA, Savannah, GA) has several beneficial properties and thus has been incorporated into the practitioner's armamentarium. No studies to date have evaluated the clinical success of using BC. The purpose of this study was to evaluate the outcome of nonsurgical root canal treatment using a single-cone and BC technique and to identify factors associated with success or failure. Methods This retrospective cohort study included patients treated in a private practice environment between 2009 and 2015. All cases, including initial and retreatment, were obturated with BC using a single-cone technique with a minimum of a 1-year recall. Patient and treatment factors were analyzed to determine their significance as prognostic factors. Outcome was evaluated based on clinical and radiographic findings at recall. Teeth were classified as healed, healing (success), or not healed (failure). Statistical analysis of potential prognostic factors was performed using the chi-square test (α = 0.05). Results Three hundred seven teeth were included in the analysis, and the average follow-up time was 30.1 months. The overall success rate was 90.9%. Lesions 5 mm in diameter. Sealer extrusion was observed in 47.4% of the cases. The presence of sealer extrusion did not have any significant effect on the treatment outcome. Conclusions BC used with a single-cone technique is a viable option for obturation.

Introduction The aim of this review was to analyze the potential of successful bonds of endodontic posts to radicular dentin as well as the limitations of the post–endodontic adhesive interface. Methods The MEDLINE/PubMed and Web of Science electronic databases were searched. The search was augmented by a manual search of the pertinent bibliographies. Results The post–endodontic adhesive interface finds application in the endodontic cohesive units. Many techniques and materials exist to improve the bond between endodontic posts and resin-based materials as well as between resin-based materials and radicular dentin. Different techniques used for the adhesion of metallic and fiber-reinforced posts are discussed and critically analyzed. Conclusions Although adhesive cementation of endodontic posts is popular, a long-term predictable bond may be compromised because of procedures related to the endodontic treatment and/or the adhesive cementation procedures. Microleakage and degradation phenomena may further jeopardize the post–endodontic adhesive interface.

Vibringe is a new device that allows continuous sonic irrigation of the canal system during endodontic treatment. The aim of this study was to compare the effect of different irrigation systems on sealer penetration into dentinal tubules of extracted single-rooted teeth.Fifty single-rooted human teeth were instrumented and randomly divided into 4 groups: group 1 (control), saline; group 2 (conventional irrigation), 17% EDTA followed by 6% NaOCl; group 3 (EndoActivator), same irrigants as group 2; group 4 (Vibringe), same irrigants as group 2. Obturation of all teeth was done with gutta-percha and SimpliSeal labeled with fluorescent dye. Transverse sections at 1 mm and 5 mm from the root apex were examined by using confocal laser scanning microscopy. Percentage and maximum depth of sealer penetration were measured by using NIS-Elements Br 3.0 imaging software.Groups 3 and 4 had a significantly greater percentage of the canal wall penetrated by sealer at the 5-mm level than group 1 (P.0125), but not group 2. No other differences were found between the groups at either section level for both the percentage of sealer penetration and maximum depth. The 5-mm sections in each experimental group had a significantly higher percentage and maximum depth of sealer penetration than did the 1-mm sections (P.0125).The use of sonic activation with either the EndoActivator or Vibringe did not significantly improve the sealer penetration when compared with conventional irrigation.

Although Resilon has been in clinical use as an endodontic obturation material for more than a decade, there is a lack of long-term clinical outcome studies. The purpose of this retrospective case-control study was to compare long-term clinical outcomes in teeth obturated with Resilon/RealSeal SE (RS) and GP/AH Plus (GP).One hundred teeth treated at Texas AM University College of Dentistry between 2007 and 2012 were included; 50 teeth were obturated with RS and 50 with GP. All cases were initial treatments without preoperative periapical radiolucencies. Success and failure were assessed on the basis of clinical signs and symptoms and/or the presence of periapical radiolucency. Chi-square test and odds ratio were used to determine the association between the obturation material and outcome. Potential prognostic factors were evaluated including age, sex, tooth location, preoperative diagnosis, and one versus multiple visits.The average recall time for RS was 5.8 years and 6.6 years for GP. Fifty-six percent of RS-obturated teeth were classified as successful at recall compared with 88% of GP-obturated teeth. RS had 5.7 times greater odds of failure compared with GP (P .001). When periapical radiolucencies were present, they tended to be larger and involve multiple roots in the RS group compared with GP group. None of the prognostic factors examined were found to have any significant effect on outcome.Within the limitations of this study, teeth obturated with RS had 5.7 times greater chance of failure compared with teeth obturated with GP.

Introduction The purpose of this study was to quantitatively investigate the effect of magnification on fine motor skills used in endodontics. Methods This study used a novel manual dexterity test that was performed with and without magnification. An 8× operating microscope and 2.5× dental loupes were used for the magnification tests. Forty subjects, 20 with microscope experience and 20 without, participated in the study. Performance on the test was evaluated by using an accuracy scoring system, and the time needed to complete the test was recorded for each subject. Results A significant increase in accuracy score with each level of magnification was demonstrated (P ≤ .05). In addition, the use of operating microscope significantly increased the time needed to complete the test among subjects with less than 3 years of microscope experience. Conclusions The use of magnification to enhance fine motor skills was supported in all age groups and experience levels.

Objective This study is to evaluate the cytotoxicity of Activ GP and RealSeal sealers in a cell culture system in vitro, and to compare them with traditional AH 26 and Kerr sealers. Study design Samples of 0.5 mg freshly mixed or set RealSeal, Activ GP, AH 26, and Kerr sealers were eluted with 200, 400, 800, and 1,200 μL cell culture medium for 24 and 72 hours. L929 cells were seeded into 96-well plates at 3 × 10 4 cells/well and cultured with 100 μL eluate from each eluate group. Cells cultured with culture medium only served as a control. After 24 hours' incubation the cytotoxicity was evaluated by MTT assay. Cell viability was calculated as the percentage of the control group, and the results were analyzed with 1-way analysis of variance. Results For the freshly mixed sealer, cell viability in the AH 26 group was less than in all of the other 3 sealer groups. The Kerr sealer group had greater cell viability than RealSeal and Activ GP groups. For the set sealer, cell viability in the AH 26 group was greater than in all of the other 3 groups. Cell viability in the RealSeal group was less than in the Kerr and Activ GP groups. Conclusion Freshly mixed RealSeal and Activ GP sealers have lower cytotoxicity than AH 26 sealer and more cytotoxicity than Kerr sealer. When sealers are set, RealSeal sealer has more cytotoxicity than AH 26 and Kerr sealer. Activ GP sealer has more cytotoxicity than AH 26 and is similar to Kerr sealer.

Intraosseous anesthesia is an effective and increasingly used technique with few reported complications. The technique uses a specialized drill to perforate the osseous cortex where local anesthetic can then be deposited to anesthetize teeth. It has been reported that separation of the perforation drills from their plastic bases can occur because of the friction generated during osseous perforation. Prolonged rotation of the perforator drills in the bone can also cause excessive heat, which can lead to bone necrosis. This report describes a case of focal osteonecrosis subsequent to intraosseous anesthesia and discusses possible etiologies of this sequela.

Endodontic treatment and dental implants are both viable treatment options to restore a compromised dentition. How these treatments impact patients' ability to chew has not been studied. The purpose of this study was to compare various parameters of masticatory function in patients with endodontically treated teeth and single-implant supported prostheses. Fifty patients were included in this study. Twenty-five patients had mandibular molar root canals, and 25 had single implant-supported prostheses in the mandibular molar region. The natural tooth contralateral to the treated side served as the internal control. Maximum bite force, chewing efficiency, and areas of occlusal contact and near contact (ACNC) were recorded for each subject, along with a questionnaire to evaluate subjective chewing ability. When compared with contralateral controls, dental implants were found to have significantly lower maximum bite forces, reduced chewing efficiency, and smaller ACNC. Endodontically treated teeth were not statistically different than their contralateral controls. These results indicate that endodontically treated natural teeth may provide more effective occlusal contact during masticatory function compared with implant-supported restorations, leading to more efficient mastication.

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 degrees 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.

Introduction Many new calcium silicate–based root filling materials have emerged in the market; however, their performance in the orthograde obturation of an open apex has not been evaluated. The purpose of this study was to compare the marginal adaptation of ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK), NeoMTA Plus (Avalon Biomed Inc, Bradenton, FL), and Endosequence BC RRM-Fast Set Putty (BC RRM-FS; Brasseler USA, Savannah, GA) after orthograde placement in roots with open apices. Methods Palatal roots of maxillary molars were instrumented to create divergent open apices and divided into 4 groups for orthograde obturation: ProRoot MTA, NeoMTA Plus, BC RRM-FS, and BC RRM-FS + BC Sealer. Using a scanning electron microscope, the quality of material adaptation at the anatomic apex was evaluated by 5 blinded examiners; 3 mm of the root end was sectioned, and gap distance was measured at the material-dentin interface. Statistical analyses were performed using the Kruskal-Wallis test. Results There were no significant differences in marginal adaptation among the 4 groups at the level of the anatomic apex ( P = .175). BC RRM-FS + BC Sealer had a significantly smaller gap size after 3-mm root end resection compared with the other 3 groups ( P Conclusions All materials showed comparable marginal adaptation at the anatomic apex when used for orthograde obturation of open apices. Application of BC Sealer before the delivery of BC RRM-FS Putty enhanced the quality of adaptation coronal to the apex.

The purpose of this in vitro study was to compare the root-end sealing of the Resilon/Epiphany system (RES) to Pro Root MTA and Super-EBA using a bacterial leakage system. Fifty-five extracted teeth were instrumented and root-ends were resected and ultrasonically prepared. Test materials were placed in the root-end preparations; Streptococcus salivarius was introduced coronally and the apical 4 mm were immersed in BHI culture medium with phenol red indicator. Bacterial leakage was monitored every 24 h for 4 wk. All positive controls leaked within 24 h; none of the negative controls leaked. Based on χ2 analysis (p < 0.05), RES and MTA leaked significantly less than Super-EBA. There was no statistical difference between RES and MTA. RES may be a viable option as a root-end filling material with good surgical isolation.

Introduction The purpose of this retrospective study was to determine the clinical and radiographic outcome of root-end surgery when EndoSequence BC Root Repair (ES-BCRR) was used as the root-end filling material and to identify any possible prognostic factors that may have affected the healing outcome. Methods Clinical records and periapical radiographs were collected from patients who had undergone endodontic microsurgery between 2009 and 2013 in a private endodontic office and had a minimum 1-year follow-up. All surgical procedures were performed by a single endodontist. ES-BCRR was used as the root-end filling material in all cases. Outcome was categorized into healed, healing, and non-healing on the basis of clinical and radiographic findings. The healed and healing cases were pooled and considered as success, and non-healing cases were considered failure. For statistical analysis of the prognostic factors, the dependent variable was the dichotomous outcome (ie, success versus failure). Results Ninety-four patients with 113 teeth met the inclusion criteria and were included in the study. The overall success rate was 92.0%. None of the prognostic factors, including age, sex, tooth position, size of periapical radiolucency, presence of a sinus tract, preoperative symptoms, and retreatment previous to surgery, appeared to have any significant effects on the outcome (P > .05). Conclusions This current study suggests that ES-BCRR is a suitable root-end filling material to be used in endodontic surgery.

Introduction The mental foramen (MF) houses vital neurovascular structures, thus making it an anatomic landmark of great importance for many dental procedures. Because the size and position of the MF can vary, proper planning is necessary beforehand to prepare the strategy of treatment. The purpose of this retrospective observational study was to determine and compare the size and position of the MF using the CS 9000 CBCT unit (Carestream Dental, Rochester, NY) to the findings from similar studies. Methods Tangential, axial, and coronal CBCT images of 106 patients were retrospectively evaluated to determine the size and position of the MF with respect to the mandibular second premolar apex and the cementoenamel junction. Distinguishing characteristics of sex, age, and race were evaluated. Results Regarding location, 53.7% of the MFs were located mesial, 45.3% distal, and 1% coincident to the apex of the mandibular second premolar. Males had a significantly greater coronal height and tangential height measurement than females. Black patients had a significantly greater distal horizontal distance from the cementoenamel junction than white patients. The mean width of the MF was 4.08 mm (axial) or 4.12 mm (tangential), whereas the mean height was 3.54 mm (tangential) or 3.55 mm (coronal). Conclusions The present study shows that the size and position of the MF can be reliably measured using limited field of view CBCT technology. The findings are similar to previous studies when considering the averages and ranges of the measurements.

Introduction Quick-Set (Avalon Biomed Inc, Bradenton, FL) is a calcium aluminosilicate cement that is a potential alternative to mineral trioxide aggregate (MTA) with greater acid resistance and faster setting. The purpose of this study was to compare the regeneration of apical tissues after root-end surgery when the apical tissues were exposed to Quick-Set or White ProRoot MTA (Dentsply Tulsa Dental Specialties, Tulsa, OK) by root-end resection. Methods The root canals of 42 mandibular premolars in 7 beagle dogs were accessed, cleaned and shaped, and obturated with Quick-Set or white MTA. Osteotomies and root-end resections were performed immediately. The dogs were sacrificed at 90 days, and the teeth and surrounding tissues were removed and prepared for histologic analysis. The sections of the apical areas were scored for inflammation, new cementum formation, periodontal ligament formation, and bone quality. Results At 90 days, both materials supported some degree of cementum formation on the surface of the material, periodontal ligament regeneration, and excellent bone quality. The only significant difference was greater inflammation found in the Quick-Set group. Conclusions Quick-Set and White ProRoot MTA had a similar effect on bone quality, cementum formation, and periodontal ligament formation after root-end surgery in dogs. Quick-Set was associated with greater inflammation.

Introduction Generex A and Generex B (calcium silicate based), Capasio (calcium-phospho-alumino silicate based) along with Ceramicrete-D (magnesium phosphate based) are being introduced as a new generation of endodontic materials with the potential to facilitate bone healing. The aim of this study was to evaluate the biocompatibility and osteogenic potential of these new materials by using primary osteoblasts. Methods Primary osteoblasts were prepared from rat calvaria and exposed to mineral trioxide aggregate (MTA), Generex A, Generex B, Capasio, and Ceramicrete-D prepared to standardized size and shape (n = 5). Trypan blue staining was used to evaluate cell viability from 1–6 days. Mineralization potential was evaluated by scanning electron microscopy for the presence of mineralized nodules. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. Results Only Generex A and MTA allowed cell growth and proliferation throughout the experiment. There were statistically significant differences between groups throughout the experiment beginning on day 1. The greatest amount of cell growth was consistently observed with Generex A and MTA. There was no difference in mineralized nodule formation between any test materials. Conclusions Generex A was the only new generation endodontic material that supported primary osteoblast growth; no material besides MTA facilitated nodule formation.

Introduction Photodynamic therapy (PDT) with high-power lasers as the light source has been proven to be effective in disinfecting root canals. The aim of this study was to evaluate the antimicrobial effect of PDT using toluidine blue O (TBO) and a low-energy light-emitting diode (LED) lamp after the conventional disinfection protocol of 6% NaOCl. Methods Single-rooted extracted teeth were cleaned, shaped, and sealed at the apex before incubation with Enterococcus faecalis for 2 weeks. Roots were randomly assigned to five experimental groups and three control groups. Dentin shavings were collected from the root canals of all groups with a #50/.06 rotary file, colony-forming units were determined, and the bacterial survival rate was calculated for each treatment. Results The bacterial survival rate of the NaOCl/TBO/light group (0.1%) was significantly lower ( P Conclusions PDT using TBO and a LED lamp has the potential to be used as an adjunctive antimicrobial procedure in conventional endodontic therapy.

Introduction: Obtaining hemostasis in the surgical crypt during periradicular surgery is essential. It allows for improved visibility and contributes to a dry environment suitable for the placement of moisture-sensitive root-end filling material. Although current materials may not be moisture sensitive during setting, hemostasis is important for proper placement of root-end filling materials during apical surgery. A new hemostatic agent, HemCon dental dressing (Patterson Dental, St Paul, MN), may improve upon the efficacy of wound healing and hemostasis both in extent and time. The aim of this study was to evaluate the hemostatic effect of HemCon in osseous wound sites and evaluate the wound healing potential and percentage of new bone formation in osseous crypts treated with HemCon. Methods: A split-mouth design was used with random allocation of sham and experimental sites in 12 rabbits. In experimental sites, either HemCon or 15.5% ferric sulfate was applied to osseous crypts created with a round bur. Hemostatic efficacy was evaluated using predetermined scores. Rabbits were sacrificed at 21 days, andtissueswereharvested andprepared forhistologic evaluation. A blinded pathologist scored samples relative to inflammation. The percentage of new bone deposition was calculated using NIS Elements software (Nikon Instruments Inc, Melville, NY). Results: There wasnostatisticalsignificantdifferenceinhemostaticefficacy or wound healing between HemCon and ferric sulfate (P > .05). The HemCon group showed a significantly higher percentage of new bone deposition compared with the controls (P < .01). Conclusions: HemCon shows promise as an adjunct to the endodontic surgical armamentarium. (J Endod 2011;37:807‐811)

Introduction Bisphosphonates have been related to impaired bone remodeling. The impact of oral bisphosphonates on periradicular healing has not been studied. The purpose of this study was to evaluate the healing of periradicular lesions in patients taking oral bisphosphonates after root canal therapy. Methods Thirty-four teeth with preoperative periradicular radiolucencies were identified in patients undergoing oral bisphosphonate therapy. These cases were examined clinically and radiographically to determine treatment outcome. Thirty-eight control teeth were selected from a pool of patients not taking bisphosphonates. Nonsurgical root canal treatment and retreatment was performed by endodontic residents and undergraduate dental students at Baylor College of Dentistry using nonstandardized protocols. Results In the bisphosphonate group, 73.5% of the lesions healed, whereas the control cases had a healing rate of 81.6%. There was no statistically significant difference between the groups (p > 0.05). Conclusion The results of this preliminary short-term study suggest that patients taking long-term oral bisphosphonates can expect a satisfactory outcome with evidence of periradicular healing after conventional root canal treatment. Thus, root canal treatment may be considered a safe and realistic alternative to extraction in patients on bisphosphonate therapy.

The objective of this study was to compare the sealing ability of ActiV GP/glass ionomer (GI) sealer (Brasseler USA, Savannah, GA), Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT), and gutta-percha (GP)/AH Plus (Dentsply Maillefer, Tulsa, OK). Seventy-three human single-rooted teeth were randomly divided into three test groups (20 canals each) and two control groups (5 positive and 8 negative). Using Enterococcus faecalis, a split-chamber bacterial leakage model was developed to evaluate the sealing ability of the three obturation systems. Samples were monitored every 24 hours for 65 days. Thirteen teeth leaked in both the Resilon/Epiphany and GP/AH Plus groups, whereas 17 teeth leaked in the ActiV GP/GI group at the end of the observation period. There were no statistically significant differences in the resistance to leakage between the three obturation systems (p > 0.05).

Objective The purpose of this study was to determine whether a premixed form of enamel matrix derivative (EMD), Emdogain-gel, has the same property as the original formula of EMD in stimulating the proliferation of osteoblasts and odontoblasts. Study design Osteoblast cell line (MC3T3) and odontoblast cell line (MDPC) were cultured in the 6-well culture plates and treated in 4 different groups: (1) culture medium control, (2) 100 μg/mL Emdogain-gel directly added to the culture medium, (3) culture medium with a culture plate insert, and (4) 100 μg/mL Emdogain-gel added onto a culture plate insert. The culture plate insert prevented direct contact between Emdogain-gel and the cells. After 3-day incubation, cell morphology was examined and the total cell number per well was counted. Data were analyzed using 1-way ANOVA. Results Emdogain-gel significantly increased cell number of both osteoblasts and odontoblasts regardless the presence of the culture plate insert. Conclusion Emdogain-gel stimulates cell proliferation of odontoblasts and osteoblasts. The direct contact between Emdogain-gel and cells is not required. Heat treatment of EMD and premix with propylene glycol alginate did not change its property of releasing bioactive molecules for promoting cell proliferation.

Resilon/Epiphany obturation system is emerging as an alternative to gutta-percha (GP). The efficacy of retreatment techniques for Resilon removal has not been determined. The purpose of this study was to evaluate two commonly used retreatment techniques in the removal of Resilon. Sixty single-canal teeth were instrumented and obturated with either Resilon/Epiphany or GP/AH Plus. Each canal was randomly allocated to receive one of the two retreatment techniques-ProFile 0.06 rotary files combined with heat or chloroform. The time required to remove the obturation material was recorded and the cleanliness of canal walls was determined by stereomicroscope and electron microscopy. The results demonstrated that chloroform combined with rotary files was more efficient in material removal compared to heat (p < 0.05). Resilon was faster to remove than GP. Both techniques resulted in cleaner canal walls in the apical third of the teeth obturated with Resilon when compared to GP (p < 0.05).

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.

Objective The purpose of this study was to determine whether the effect of enamel matrix derivative (EMD) on osteoblast proliferation is dependent on direct contact between EMD and the cells. Study design MC3T3-E1 cells were seeded onto 6-well culture plates at an initial density of 5000/cm2 in Dulbecco's modified eagle medium (DMEM) with 10% fetal bovine serum (FBS). Serum was removed from the culture medium after 24 hours with or without the addition of EMD. Four groups were evaluated: group 1, DMEM only; group 2, DMEM with 100 μg/mL EMD directly added to the culture medium; group 3, DMEM with a culture plate insert (30-mm diameter; 0.4-μm pore size) only; group 4, DMEM with 100 μg/mL EMD added onto a culture plate insert. The porous membrane of the insert prevented direct contact between EMD and the cells. After 3-day incubation, cell morphology was examined and the total cell number per well was counted and analyzed using 1-way ANOVA. Results EMD formed precipitated aggregates on the membrane of the culture insert with the same appearance as when it was added directly to the medium. The culture plate insert alone did not cause any changes in cell morphology or proliferation. The addition of EMD significantly increased cell number regardless the presence of the culture plate insert. Conclusion This study suggests that direct contact between EMD and osteoblasts is not required to induce cell proliferation. Soluble peptides released from EMD may contribute to the stimulating effects of EMD on cell proliferation.

Objective. Mineral trioxide aggregate (MTA) is being widely used for root-end fillings, pulp capping, perforation repairs, and other endodontic procedures. MTA and Portland cement (PC) have many similar physical, chemical, and biologic properties. PC cement has shown promising potential as an endodontic material in several studies in vitro and in vivo. The purpose of this study was to compare the cytotoxic effect in vitro and the tissue reaction of MTA and Portland cement in bone implantation in the mandibles of guinea pigs. Study Design. Millipore culture plate inserts with freshly mixed or set material were placed into the culture plates with already attached L929 cells. After an incubation period of 3 days, the cell morphology and cell counts were studied. Adult male guinea pigs under strict asepsis were anesthetized, during which a submandibular incision was made to expose the symphysis of the mandible. Bilateral bone cavities were prepared and Teflon applicators with freshly mixed materials were inserted into the bone cavities. Each animal received 2 implants, one filled with ProRoot and 1 with PC. The animals were killed after 2 or 12 weeks, and the tissues were processed for histologic evaluation by means of light microscopy. Results. There was no difference in cell reactions in vitro. Bone healing and minimal inflammatory response adjacent to ProRoot and PC implants were observed in both experimental periods, suggesting that both materials are well tolerated. Conclusions. MTA and PC show comparative biocompatibility when evaluated in vitro and in vivo. The results suggest that PC has the potential to be used as a less expensive root-end filling material. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;95:483-9)