OBJECTIVE: To evaluate the clinical effect of root canal obturation therapy using cold flowable gutta-percha on young permanent teeth after apexification. METHODS: Ninety cases of young permanent teeth with pulp necrosis or periapical periodontitis treated by apexification were randomly divided into two groups. The cases in each group were divided into single root canal and multiple root canal according to the number of the root canal, and divided into classifications Ⅰ, and Ⅱ/Ⅲ/Ⅳ according to Frank's classification of root development after apexification. Cold flowable gutta-percha and warm gutta-percha obturation techniques were used for root canal obturation of the two groups. The operation time was recorded, and the patients' therapy pain degree was evaluated by visual analog scale (VAS) immediately after operation. Periapical X-ray was performed after operation to evaluate the effect of the root canal filling. The total length of the root was divided into equal three parts on the X-ray film, and three-dimensional tightness of the apical, middle, and coronal region of the root canals were statistically analyzed respectively. Clinical examinations and X-ray examination were performed 6 and 12 months after the operation to evaluate the treatment success rate. RESULTS: The operation time of cold flowable gutta-percha group was significantly lower than that of the control group, which were 51 s and 74 s (P < 0.05); The percentages of pain and discomfort in the two groups were 26.67% and 40.00%, respectively. There were two cases of underfilling and no overfilling in both groups. The percentages of proper filling and tight three-dimensional obturation in the experimental and control groups were 71.11% and 60.00% respectively; and the percentages of tight three-dimensional obturation in the apical third areas were 86.67% and 66.67%, the difference was significant (P < 0.05). There was no significant difference in the three-dimensional tightness between the two groups in the middle and coronal third areas. The percentages of tight three-dimensional obturation in classification Ⅰ groups were 86.67%, 83.33%, 93.33% and 76.67%, 90.00%, 96.67% in experimental and control group, respectively; The percentages of classification Ⅱ/Ⅲ/Ⅳ groups were 86.67%, 86.67%, 100.00% and 46.67%, 86.67%, 100.00%, respectively, and the difference was significant (P < 0.05). There were no apical lesions that occurred in either group during the one-year review period. CONCLUSION The application of cold flowable gutta-percha on young permanent teeth root canal obturation after apexification can achieve good obturation effect. The root obturation effect in the apical third area is significantly better than that of warm gutta-percha obturation techniques. Cold flowable gutta-percha can shorten the clinical treatment time and ameliorate the patients' therapy comfort.
Apexification ; Dental Pulp Cavity ; Gutta-Percha ; Humans ; Radiography ; Root Canal Filling Materials ; Root Canal Obturation ; Root Canal Preparation

Compared with cold lateral condensation and continuous wave of condensation which are classically used in clinical, newly emerging single-cone obturation technique is easy-to-operate as well as time-saving. Especially when combined with bioceramic root canal sealers of improved physicochemical and biological properties, single-cone obturation technique showed satisfactory short-term outcomes in clinical observations. However, difficulties still exist in avoiding the root canal overfilling and in operating the retreatment. Besides, the long-term effects of single-cone obturation with bioceramic sealers still remain unclear. This article makes an overview on the history and development of single-cone obturation ,and provides analysis of its pros and corns. Furthermore, we would also like to summarize its clinical application and look into its future improvements.
Epoxy Resins/chemistry* ; Gutta-Percha/chemistry* ; Retreatment ; Root Canal Filling Materials/therapeutic use* ; Root Canal Obturation/methods* ; Root Canal Therapy

OBJECTIVES: The safety of root canal filling with 200 °C hot gutta-percha was investigated to study the effect of continuous wave technique combined with high-temperature injectable gutta-percha condensation technique on the surface temperature of periodontal tissue. METHODS: CT technique and Mimics, Geomagic, and Solidworks software were utilized to build the entity models of alveolar bone, dentin and root canal, periodontal ligament, and blood flow, respectively, which were then assembled in Solidworks into a finite element model of tooth with blood flow. By utilizing ABAQUS collaborative simulation platform, fluid-structure coupling was analyzed on the whole process of root canal filling. Consequently, the surface temperature of the periodontal tissue was obtained. RESULTS: In the absence of blood flow, the temperature of the periodontal ligament surface reached 50.048 ℃ during root canal filling with 200 ℃ gutta-percha. Considering blood flow, the temperature of periodontal ligament surface was 39.570 ℃. CONCLUSIONS The temperature of the periodontal ligament surface increased when the continuous wave root canal was filled with 200 ℃ gutta-percha, and the periodontal tissue was not damaged.
Dental Pulp Cavity ; Finite Element Analysis ; Gutta-Percha ; Hot Temperature ; Humans ; Periodontium ; Root Canal Filling Materials ; Root Canal Obturation ; Temperature

OBJECTIVE: This study evaluated the presence of residual root canal filling material after retreatment using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Extracted human teeth (single- and double-rooted, n = 21/each; C-shaped, n = 15) were prepared with ProFile and randomly assigned to three subgroups for obturation with gutta-percha and three different sealers (EndoSeal MTA, EndoSequence BC sealer, and AH Plus). After 10 days, the filling material was removed and the root canals were instrumented one size up from the previous master apical file size. The teeth were scanned using micro-CT before and after retreatment. The percentage of remaining filling material after retreatment was calculated at the coronal, middle, and apical thirds. Data were analyzed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni post hoc correction. RESULTS: The tested sealers showed no significant differences in the percentage of remaining filling material in single- and double-rooted teeth, although EndoSeal MTA showed the highest value in C-shaped roots (p < 0.05). The percentage of remaining filling material of AH Plus and EndoSeal MTA was significantly higher in C-shaped roots than in single- or double-roots (p < 0.05), while that of BC sealer was similar across all root types. EndoSeal MTA showed the highest values at the apical thirds of single- and double-roots (p < 0.05); otherwise, no significant differences were observed among the coronal, middle, and apical thirds. CONCLUSIONS: Within the limitations of this study, a large amount of EndoSeal MTA remained after retreatment, especially in C-shaped root canals.
Dental Pulp Cavity ; Gutta-Percha ; Humans ; Pemetrexed ; Retreatment ; Root Canal Obturation ; Tooth

OBJECTIVES: This study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength. MATERIALS AND METHODS: Sixty maxillary canines were divided into 6 groups (n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine. RESULTS: Ultrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA (p < 0.05). US improved the push-out bond strength for all the cements (p < 0.05). CONCLUSIONS: The US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested.
Calcium ; Dentin ; Dihydroergotamine* ; Endodontics ; Hand ; Microscopy, Electron, Scanning ; Miners ; Pemetrexed ; Retrograde Obturation ; Tooth ; Transducers ; Ultrasonics* ; Ultrasonography

OBJECTIVES: To evaluate sealing ability of root canals obturated with bioceramic-impregnated gutta percha cone (BCC) or gutta percha (GP), with bioceramic sealer (BCS) or AH Plus (AH; Dentsply-Maillefer), in roundly-prepared canals using matched single-cone technique, based on bacterial leakage test, and to analyze obturation quality using micro-computed tomography (CT) analysis. MATERIALS AND METHODS: Ninety-two distobuccal roots of maxillary molars were prepared using nickel-titanium files to apical size 40/0.06. The roots were divided into 4 groups (n = 20) that were obturated with a master cone and sealer: GP/AH, BCC/AH, GP/BCS, and BCC/BCS. Bacterial leakage model using Enterococcus faecalis was used to evaluate sealing ability for 60-day period. Obturated samples from each group (n = 4) were analyzed using micro-CT. RESULTS: All groups showed bacterial leakage at 20%–45% of samples with mean leakage times of 42–52 days. There were no significant differences in bacterial leakage among the groups. Micro-CT showed minimal gaps and voids in all groups at less than 1%. CONCLUSIONS: In roundly-prepared canals, the single cone obturation with BCC/BCS was comparable to GP/AH for bacterial leakage at 60 days.
Dental Pulp Cavity ; Enterococcus faecalis ; Gutta-Percha ; Molar ; Root Canal Obturation

OBJECTIVES: To determine the optimal timing for post space preparation of root canals sealed with epoxy resin-based AH Plus sealer in terms of its polymerization and influence on apical leakage. MATERIALS AND METHODS: The epoxy polymerization of AH Plus (Dentsply DeTrey) as a function of time after mixing (8, 24, and 72 hours, and 1 week) was evaluated using Fourier transform infrared (FTIR) spectroscopy and microhardness measurements. The change in the glass transition temperature (Tg ) of the material with time was also investigated using differential scanning calorimetry (DSC). Fifty extracted human single-rooted premolars were filled with gutta-percha and AH Plus, and randomly separated into five groups (n = 10) based on post space preparation timing (immediately after root canal obturation and 8, 24, and 72 hours, and 1 week after root canal obturation). The extent of apical leakage (mm) of the five groups was compared using a dye leakage test. Each dataset was statistically analyzed by one-way analysis of variance and Tukey's post hoc test (α = 0.05). RESULTS: Continuous epoxy polymerization of the material with time was observed. Although the T(g) values of the material gradually increased with time, the specimens presented no clear T(g) value at 1 week after mixing. When the post space was prepared 1 week after root canal obturation, the leakage was significantly higher than in the other groups (p < 0.05), among which there was no significant difference in leakage. CONCLUSIONS: Poor apical seal was detected when post space preparation was delayed until 1 week after root canal obturation.
Bicuspid ; Calorimetry, Differential Scanning ; Dataset ; Dental Pulp Cavity* ; Fourier Analysis ; Glass ; Gutta-Percha ; Humans ; Polymerization ; Polymers ; Post and Core Technique ; Root Canal Obturation ; Root Canal Preparation ; Spectrum Analysis ; Transition Temperature

OBJECTIVES: The aims of this study were to quantify tug-back by measuring the pulling force and investigate the correlation of clinical tug-back pulling force with in vitro gutta-percha (GP) cone adaptation score using micro-computed tomography (µCT). MATERIALS AND METHODS: Twenty-eight roots from human single-rooted teeth were divided into 2 groups. In the ProTaper Next (PTN) group, root canals were prepared with PTN, and in the ProFile (PF) group, root canals were prepared using PF (n = 14). The degree of tug-back was scored after selecting taper-matched GP cones. A novel method using a spring balance was designed to quantify the tug-back by measuring the pulling force. The correlation between tug-back scores, pulling force, and percentage of the gutta-percha occupied area (pGPOA) within apical 3 mm was investigated using µCT. The data were analyzed using Pearson's correlation analysis, one-way analysis of variance (ANOVA) and Tukey's test. RESULTS: Specimens with a strong tug-back had a mean pulling force of 1.24 N (range, 0.15–1.70 N). This study showed a positive correlation between tug-back score, pulling force, and pGPOA. However, there was no significant difference in these factors between the PTN and PF groups. Regardless of the groups, pGPOA and pulling force were significantly higher in the specimens with a higher tug-back score (p < 0.05). CONCLUSIONS: The degree of subjective tug-back was a definitive determinant for master cone adaptation in the root canal. The use of the tug-back scoring system and pulling force allows the interpretation of subjective tug-back in a more objective and quantitative manner.
Dental Pulp Cavity ; Gutta-Percha ; Humans ; In Vitro Techniques ; Methods ; Root Canal Obturation ; Tooth ; X-Ray Microtomography

Root canal filling is performed as the final and most important procedure of root canal treatment. The superior 3D filling is the key determinant of endodontic success. However, such procedure remains a challenge because of the complexity of the root canal system and the limitation of root canal filling materials and methods. This paper provides an overview of current principles and practices in root canal filling, focusing on advantages, disadvantages and indications. The process errors and countermeasures in various root canal filling methods are also discussed. This review provides guidance and help for clinical and practice to achieve a satisfactory root canal filling and improve root canal treatment outcome.
Dental Pulp Cavity ; Humans ; Root Canal Filling Materials ; Root Canal Obturation ; Root Canal Therapy

Root canal therapy is the most efficient way to treat pulptitis and periapical inflammation, which can clear infections of root canal systems, fill the root canal firmly, and avoid reinfection. However, the variations in root canal morphology and complexity of infection confer difficulty in thoroughly eliminating microorganisms and their by-products in the root canal system, especially in the root apex area (including the top one-third of the root canal and periapical tissue), which is described as the hardest area to clean during endodontic treatment. Infection is difficult to remove entirely because the apex area is hard to approach using dental instruments and because of the existence of special morphological structures, such as apical ramification, intercanal anastomoses, and lateral branch of root canal. This review gives a brief introduction of the characteristics and difficulties of apical infection and knowledge on how to control such infections, including root apex preparation, irrigation and disinfection, and root canal filling.
Dental Pulp Cavity ; Humans ; Infection Control ; Periapical Periodontitis ; Root Canal Filling Materials ; Root Canal Irrigants ; Root Canal Obturation ; Root Canal Preparation ; Root Canal Therapy