Influencia de la instrumentación con lima única en la calidad de la obturación del sistema de conductos radiculares mediante la técnica de condensación lateral modificada con gutapercha inyectada

The main objective in endodontic therapy is to simplify procedures with full safety and efficacy. As an alternative to multifile rotary systems, single file reciprocating systems is created, in order to reduce cyclic fatigue to lower the risk of fracture of the instruments, the deformity of the root canal, speed and simplicity in conformation. Later, they appeared single file systems of continuous rotation also increased the speed and simplicity. In order to analyze the capacity to shape the root canals of these endodontic systems this study. 2. Objectives. General: Describe the adaptation of filling materials to the walls of the root canal with modified lateral condensation gutta-percha injected filling technique depending on the system used canal preparation. Specific: Measure the adaptation and penetration of filling materials in the dentinal tubules with Reciproc®, WaveOne®, One Shape® and hand files K-Flexofile® systems. Compare the interface between the filling materials and canal dentin of 4 groups, comparing the reciprocating and continuous movement groups and the rotary with the manual. 3. Material and Methods: 40 single-rooted incisors, canines human teeth and palatal roots of maxillary premolars and mandibular premolars were selected using strict inclusion and exclusion criteria. The conformation of the canals is performed by single file system, two reciprocating motion Reciproc (Group A; RE) and Waveone (Group B; WO), and one continuous motion One Shape (Group C; OS), and finally a hand files K-Flexofile (Group D, KF). Later, they were filled with modified lateral condensation gutta-percha injected filling technique. Finally, the degree of adaptation and maximum length of penetration of filling material to the root canal in the coronal, middle and apical by laser confocal microscope and scanning electron microscope was observed. 4. Results: adaptation of filling materials observed by confocal laser microscopy, statistically significant differences between the apical thirds of WO and KF, with a lower value for WO were obtained. There were also differences between the apical, middle and coronal thirds through WO, OS and KF, with worse results in apical to the three groups. Length maximum penetration with laser confocal microscope obtained significant differences in three thirds RE, with worst result in apical and between the apical and coronal thirds of WO, OS and KF. The successful adaptation with the scanning electron microscope had the lowest value in the middle third of WO all groups, which was statistically different middle thirds of RE, OS and KF, and WO also showed significant differences in their apical and coronal thirds. The maximum mismatch with scanning electron microscopy results obtained statistical differences in apical with KF with the lowest value, compared with RE and WO. It was also different from the middle third of OS with the lowest value of RE, WO and KF, as well as differences between the middle third of RE with KF, with the highest value in the middle third to RE were also found. The OS group presented differences between their middle and coronal thirds, and KF was different apical third, with the shortest length, middle and coronal. 5. Discussion: The advantages of using files with reciprocating motion have a reduced cyclic fatigue compared with the continuous motion, and shaping speed, short learning curve and confort. Yared (2008) was the first to he tested the technique of reciprocating shaping. However, they also have drawbacks, such as fracture during rotation and high cost. Modified lateral condensation gutta-percha injected filling technique is considered a combination of lateral condensation and continuous wave condensation technique. Gutta-percha allows controlled placement, low cost, provides high density obturation and better seal the apex and greater fluidity canals irregularities. The filling technique limited comparison with other authors, because it is a technique used in the University of Valencia, but from which no publications yet. The analysis used two types of microscopy was because of complementary techniques are discussed, as analyzing the results could be observed the coincidences between the information provided by both techniques. The laser confocal microscope allowed verifying adaptation of obturation by penetrating the fluorescent compound in the dentin, which was considered as adaptation, and scanning electron microscopy allowed adaptation check zones higher magnification. Because of this adaptation percentages were significantly higher with the scanning microscope that the confocal, since it has to produce the cement penetration in the dentinal tubules to be considered as an adaptation of the cement, which is finally returned in the results . However, using these techniques microscopy it is considered a destructive technique, because the samples must sectioning to allow observation. 6. Conclusions: The adaptation of filling materials with RECIPROC, One Shape and limes K Flexofile was similar, with no differences between them. However, Waveone had a lower marginal adaptation. Got adaptation RECIPROC followed a regularity between different radicular thirds, with no differences between them; maximum penetration occurred in the coronal third where he obtained the best results in terms of filtration. Waveone showed differences in the apical and middle thirds with other single file system and hand file, and its thirds; maximum penetration was observed in the coronal third. One Shape adapted worst in the apical third; and maximum adaptation occurred in the coronal third. K Flexofile got the worst adaptation in the apical third and maximum adaptation in the coronal third. The four systems showed, in general terms, an adaptation can be considered as satisfactory. Reciprocating motion groups compared to continuous motion obtained worse adaptations, with differences in the middle third. The manual instrumentation group compared to rotary instrumentation groups showed differences from the middle and apical thirds of rotating groups.