Apical filling characteristics of carrier-based techniques vs. single cone technique in curved root canals

Assessing the impact of obturation techniques, kinematics and irrigation protocols on apical debris extrusion and time required in endodontic retreatment

The aim of the study was to evaluate the impact of kinematics and irrigation protocols on the extrusion of apical debris during removal of different obturation techniques. A total of 144 single-rooted teeth were instrumented and obturated with Thermafil+AH Plus, Thermafil+AH Plus Bioceramic and single gutta-percha cone+AH Plus Bioceramic. Samples were divided according to the retreatment kinematics: continuous rotation or Jeni motion. Each sub-group was subjected to conventional irrigation or irrigation activated by EDDY. Extruded debris was collected in Eppendorf tubes, weighted and retreatment time was digitally recorded. Data were analysed with two-way ANOVA (p < 0.05). Debris extrusion was not significantly different between all groups. EDDY activation system and CanalPro Jeni required significantly longer time compared with other groups to remove Thermafil+AH Plus and single cone+AH Plus Bioceramic. Within current limitations, obturation technique, irrigation protocol and kinematics tested had no influence on apical extrusion debris, while they significantly impacted the retreatment time.

Comparison of Two Root Canal Filling Techniques: Obturation with Guttacore Carrier Based System and Obturation with Guttaflow2 Fluid Gutta-Percha

Introduction: The aim of the present study was to compare the quality of the root canal obturation obtained with two different techniques, i.e., thermoplastic gutta-percha introduced through a carrier (GuttaCore) and fluid gutta-percha (GuttaFlow2). Materials and Methods: The study included 40 permanent single-rooted human teeth, divided into two groups and obturated with Guttaflow (group G) and with GuttaCore (group T). The teeth were fixed and transversely sectioned, they were examined by scanning electron microscopy. The dentin–cement–gutta–percha interface and the percentage of voids produced by the two techniques were statistically analyzed. Results: GuttaCore showed a better filling in the apical third of the canal with a percentage of voids equal to 5%. GuttaFlow showed a lower percentage of voids in the middle and coronal thirds of the canal, 1.6% of coronal voids. Statistical analysis showed a statistically significant difference in the percentage of voids in the two groups (GuttaCore and Guttaflow2) in each portion. Conclusions: GuttaFlow2 seems to flow optimally in the middle and coronal third of the canal, with greater difficulty in filling the apical third. Due to the rigidity of the carrier, GuttaCore is able to reach better the most apical portions of the canals, with greater difficulty in creating the three-dimensional seal at the level of the middle third and coronal third.

A critical analysis of research methods and experimental models to study root canal fillings

Canal filling materials and techniques have been one of the most studied topics in Endodontics. A simple search using the mesh term "root canal filling" in PubMed revealed more than 11,000 articles, an impressive number that is much higher than "root canal disinfection" (5,544 articles) or even the popular "root canal preparation" (8,527 articles). The overriding importance attributed to root filling procedures is not merely intuitive. It derived from the appealing relevance given by the appearance of the white lines in common radiographs grounded on retrospective clinical data that had identified the quality of a root filling as one of the major causes of treatment failure (lack of healing). Since the publication of the Washington study, impressive efforts have been made for the release of new materials and techniques, as well as, for the development of a plethora of laboratory methods to assess the quality of root filling procedures. This narrative review aims to address and discuss the most relevant laboratory methods to assess the root canal filling. Since filling quality improvements have not translated into higher success rates, as reported in longitudinal clinical studies, more than to deliver a simple methodology-based review, this paper aims to present an in-depth critical view on the assessment of laboratory methods used to study the filling materials and techniques. Recent data indicate that the long-term dimensional stability/degradation over time of endodontic sealers plays a central role in the treatment outcome. In this context, laboratory methods should be developed focusing on predicting, at least to some degree, the long-term clinical behaviour of root canal fillings, rather than simply ranking different materials or techniques.

Root Canal Filling Quality Comparison of a Premixed Calcium Silicate Endodontic Sealer and Different Carrier-Based Obturation Systems

Background: The number of voids within the root canal obturation is a relevant parameter to describe the quality of the technique, as well as to predict long-term prognosis. The aim of this study was to evaluate the quality of root canal obturation in curved root canals filled with Thermafil, GuttaCore, GuttaFusion and lateral compaction with AH Plus and EndoSequence BC sealer, by means of percentage of gutta-percha and sealer filled area. Methods: 200 curved canals of mandibular molars were divided in five groups (n = 40). Each specimen was evaluated at 3, 6 and 9 mm from the apex. A total of 600 samples were analyzed. Obturation was performed with either Thermafil (TH), GuttaCore (GC), GuttaFusion (GF) or lateral compaction (LC), using AH Plus as sealer. In another group EndoSequence BC sealer (BC) was used. Subgroups (n = 20) were made depending on the use of sonic activation during the placement of the sealer. The percentage of total obturation material was analyzed as an indirect measurement of percentage of voids. Results: GF showed a better performance at the apical level, while GC showed the higher percentage of total obturation at the coronal area. No differences were observed for the activation of sealers in any of the groups. Statistical analysis was performed by using two-way ANOVA. Statistical significance was set at CI: 95% (p < 0.05). Conclusions: Sonic activation of sealers did not show any benefit to avoid the presence of voids within obturation of curved canals. Following the manufacturer recommendations, we found that TH did not show benefits when applied to curved canals.

Assessment of Quality of Root Canal Filling with C Point, Guttacore and Lateral Compaction Technique: A Confocal Laser Scanning Microscopy Study

Objective:

The purpose of this in vitro study was to compare the quality of root canal filling of C Point, GuttaCore and lateral compaction using confocal laser scanning microscopy.

Methods:

Ninety recently extracted human mandibular incisors with single canal were selected. Canals were prepared with ProTaper instruments to size F3 and obturated using C Point, GuttaCore or lateral compaction technique. Endosequence BC sealer was labeled with Rhodamine B dye to allow analysis under a confocal microscope. The percentages of gutta-percha filled area (PGFA), sealer filled area (PSFA), voids (POV) and interfacial adaptation (IA) was assessed at 2, 5 and 8 mm from the apex, using image analysis software. Kruskal–Wallis followed by Mann Whitney U tests were used for data analysis, and the P value was set at 0.05 (P=0.05).

Results:

No significant difference was seen among the three groups at 2 mm level for PGFA, PSFA and voids (P>0.05). At 5 and 8 mm levels, canals filled with GuttaCore had significantly higher PGFA and lower PSFA than lateral compaction and C Point. Highest POV was seen for lateral compaction group followed by C Point and GuttaCore.

Conclusion:

Out of the three techniques examined, best results in terms of quality of root canal filling were observed for GuttaCore. C Point system was found to be associated with internal defects such as tears and delamination which may adversely affect the long term performance of this system.

Evaluation of different root canal filling techniques in severely curved canals by micro-computed tomography

AIM

To fill the severely curved root canals with different filling techniques and to compare these techniques using micro-computed tomography (micro-CT).

MATERIALS AND METHODS

Sixty extracted mandibular first molars (degree of root canal curvature >25°) were selected. All samples were divided into four groups and filled with one of the following techniques: lateral condensation, single-cone, continuous-wave obturation, and core carrier. After they were scanned by micro-CT, the total area, filled area and void area of the root canal were calculated. The Mann-Whitney U and Kruskal-Wallis tests were used for statistical analysis (p < 0.05).

RESULTS

It was shown that significantly more filling material was used in the lateral condensation and core carrier technique groups at 2 and 5 mm than in the single-cone and continuous-wave obturation technique groups (p < 0.05). It was observed no statistically significant difference at 8 mm (p > 0.05).

CONCLUSION

No technique could completely fill in root canal. Regarding the coronal part, all techniques can be used for more effective filling as long as a good condensation is achieved. The use of a plugger with an optimal size according to the localisation of root canal curvature and the choice of a heat-resistant root canal sealer affects the success of the treatment in the thermoplastic techniques.

Apical Displacement and Residual Root Canal Filling with Single-Cone After Post Space Preparation: A Micro-CT Analysis

The purpose of this study was to evaluate the presence of residues after post space preparation (PSP) and establish whether the apical displacement of the gutta-percha was affected by the moments and methods of PSP in teeth filled by the single-cone technique. The root canals of 20 bovine incisor teeth were instrumented with Reciproc and filled with single-cone and AH Plus. The specimens were divided into 4 groups according to the moment and method of PSP (n=5): immediate with drill, immediate with thermoplasticizer, delayed with drill and delayed with thermoplasticizer. Micro-CT scans were performed before and after the PSP for residues of the root canal filling (1) and analysis of apical displacement (2). Data were analyzed by using 2-way repeated measurement ANOVA (1) and 2-way ANOVA (2) followed by the Tukey's test (a=0.05). Significance effect on the residues percentage remaining for methods (p=0.044), for moments (p=0.006), for thirds repetition (p<0.001), and for interaction between methods and thirds (p<0.001), and moments and thirds (p=0.044). Significance effect on the apical displacement of root canal filing was detected for methods (p=0.008), however no difference was found between moments (p=0.617). In general, PSP using drill resulted in more homogeneous root canal preparation, mainly when made immediately. For all other combinations between methods and moments for PSP, the middle and apical thirds presented significant higher residues remaining. Thermo method performed in both moments and the drill method performed immediately had displacement in the apical direction, representing extrusion of the root filling material.