Laser applications in smear layer removal from posterior root canals: A comparative study.

Aim: The aim of the study is to evaluate erbium laser efficiency in removing smear layer from mesial roots of mandibular first molars at different laser settings. Subjects and Methods: One hundred (100) mandibular first molars were selected. Ninety six (96) mesial roots were assigned to two experimental groups according to the laser wavelength applied: I. Er, Cr: YSGG and II. erbium-doped yttrium aluminum garnet laser system. Four samples were used as control group. Samples of each group were distributed into two subgroups (A and B), following specific irrigation protocol. Each subgroup was divided into four subcategories according to the applied power laser. Each subcategory consisted of six samples. Teeth were observed under scanning electron microscope. Statistical Analysis: Results were statistically analyzed with Kruskal-Wallis and Mann-Whitney test (SPSS statistics software). Results: No statistically significant difference was observed between experimental groups I and ΙΙ. However, statistically significant difference was found among subgroups IA and ΙB and ΙIA and ΙΙΒ. In every root third, groups IIA and ΙΙB had better outcomes but it was not statistically significant. There was no statistically significant difference among subcategories of Group I (ΙΑ1-4 and ΙΒ1-4) and Group ΙΙ (ΙΙΑ1-4 and ΙΙΒ1-4). Conclusion: Erbium laser with tested parameters did not completely remove the smear layer from the root canals. Chelating factors can contribute in the laser mechanism of smear layer removal from apical part of narrow and curved root canals.

Retreatability of root canals filled with Gutta percha and a novel bioceramic sealer: A scanning electron microscopy study.

AIM: This study aimed to evaluate the residual filling material and the reestablishment of working length (WL) and apical patency after retreatment of BioRoot™ RCS, versus TotalFill® BC Sealer, and AH26, used in a single cone obturation technique. MATERIALS AND METHODS: Sixty single-rooted permanent canines were instrumented up to size 40/.04 (Sendoline, Täby, Sweden). The samples were filled with GP/AH26 (Group 1), GP/TotalFill BC Sealer (Group 2), and GP/BioRoot RCS (Group 3). Eight teeth were used in the positive and negative control groups. Canals were retreated using the Protaper Universal retreatment files (Dentsply Maillefer, Ballaigues, Switzerland) and further instrumented up to size 50/.04 (Sendoline, Täby, Sweden). The ability to reestablish WL and apical patency was recorded. Furthermore, the samples were observed under a scanning electron microscope, in order to evaluate the residual filling material. Data were analyzed statistically with the Fisher's exact and the Kruskal-Wallis tests (P < 0.05). RESULTS: There was no statistically significant difference in the WL and patency recovery among the groups. Neither the intragroup comparison among canal thirds nor the intergroup comparison in each canal third or in total canal area revealed any significant differences in the percentage of the remaining filling material after retreatment. CONCLUSION: Residual material debris was observed in all samples regardless of the sealer used. All the sealers were removed to a similar extent. The WL and patency were reestablished sufficiently in all groups.

Retreatment Efficacy of Endodontic Bioceramic Sealers: A Review of the Literature / Eficacia del retratamiento de cementos endodónticos biocerámicos: Revisión de Literatura

Abstract The endodontic retreatment is a feasible solution when post-operative apical periodontitis persists or develops. The complete removal of the filling materials is important in order to ensure the unobstructed contact of the intracanal disinfectants with the microbes. As a new generation of bioceramic endodontic sealers has emerged, their removal efficacy from the root canal system during retreatment is a matter of concern among clinicians. The aim of this article is to provide a comprehensive review of the current literature on the retreatability of these novel obturating materials. A significant amount of bioceramic sealer remnants in the root canal walls was observed in all studies. Even though canal cleanliness could not be obtained at an ideal level, the re-establishment of the working length and patency can be considered manageable and comparable to other endodontic sealers.

Resumen El retratamiento endodóntico es una solución factible cuando la periodontitis apical post-operatoria persiste o se desarrolla. La eliminación completa de los materiales obturadores es importante para garantizar el contacto y acción de los desinfectantes e irrigantes endodónticos con los microorganismos persistentes. A medida que ha surgido una nueva generación de selladores endodónticos biocerámicos, su eficacia de eliminación del sistema de conductos radiculares durante el retratamiento es motivo de preocupación entre los profesionales. El objetivo de este artículo es proporcionar una revisión exhaustiva de la literatura actual sobre la influencia o posibles limitantes del uso de este tipo de cementos bioactivos durante el retratamiento endodóntico. Los estudios determinaron una cantidad significativa de restos de selladores biocerámicos en las paredes del conducto radicular. Aunque la limpieza del canal no se pudo obtener a un nivel "ideal", el restablecimiento de la longitud de trabajo y la permeabilidad se puede considerar manejable y comparable a otros selladores endodónticos.

Comparison of different agitation methods for the removal of calcium hydroxide from the root canal: Scanning electron microscopy study.

AIM: This ex vivo study compared the efficiency of different irrigations systems to remove calcium hydroxide from root canal walls, especially from the apical third by using scanning electron microscopy (SEM). MATERIALS AND METHODS: Eighty-four single-rooted teeth were divided into 4 groups of 20 teeth each, according to different irrigation protocols using a 30-gauge slot-tipped needle, ultrasonic irrigation system, erbium-doped yttrium aluminum garnet laser (Er: YAG) laser, and EndoVac system. The rest 4 teeth were used as control groups (2 positive and 2 negative control groups). After coronal access, all teeth were instrumented by Protaper Next rotary files (Dentsply-Maillefer, Ballaigues, Switzerland) up to size X3, followed an irrigation protocol and filled with pure calcium hydroxide powder mixed with saline. Teeth were stored in an incubator for 7 days, and then, calcium hydroxide was removed using 3 techniques: Manually (Group 1), by ultrasonic irrigation (Group 2), by laser Er: YAG and x-pulse tip (Group 3), and by EndoVac system (Group 4). The teeth of control groups were instrumented as the experimental groups; no removal technique was applied in positive group, whereas in negative one, the root canals were left empty. Teeth were sectioned longitudinally and observed under SEM Results were statistically analyzed with the Kruskal-Wallis Test and Mann-Whitney Test. RESULTS: The results showed a significant difference between laser and the other three groups in coronal and middle root third, but no statistic difference in apical third. CONCLUSION: Laser improved the removal of calcium hydroxide in comparison with conventional techniques.

Periradicular Tissue Responses to Biologically Active Molecules or MTA When Applied in Furcal Perforation of Dogs' Teeth.

The aim of this study was the comparative evaluation of inflammatory reactions and tissue responses to four growth factors, or mineral trioxide aggregate (MTA), or a zinc-oxide-eugenol-based cement (IRM) as controls, when used for the repair of furcal perforations in dogs' teeth. Results showed significantly higher inflammatory cell response in the transforming growth factorß1 (TGFß1) and zinc-oxide-eugenol-based cement (IRM) groups and higher rates of epithelial proliferation in the TGFß1, basic fibroblast growth factor (bFGF), and insulin growth factor-I (IGF-I) groups compared to the MTA. Significantly higher rates of bone formation were found in the control groups compared to the osteogenic protein-1 (OP-1). Significantly higher rates of cementum formation were observed in the IGF-I and bFGF groups compared to the IRM. None of the biologically active molecules can be suggested for repairing furcal perforations, despite the fact that growth factors exerted a clear stimulatory effect on cementum formation and inhibited collagen capsule formation. MTA exhibited better results than the growth factors.

Internal root resorption studied by radiography, stereomicroscope, scanning electron microscope and computerized 3D reconstructive method.

AIM AND METHODOLOGY: Two cases of internal tooth resorption were examined. A mandibular premolar and a mandibular canine were studied after they were extracted using radiographs, a stereomicroscope (SM) and a scanning electron microscope (SEM). Lastly, 3D images of the sectioned teeth were obtained(3D). RESULTS: Radiographically, internal root resorption was shown as a uniform radiolucency. By SM examination, an extensive destruction of dentin was seen, while, by SEM examination, a disappearance of dentinal tubules was clear. The 3D reconstructive method revealed a circumscribed, oval-shaped defect that did not perforate the cemental layer. CONCLUSIONS: Internal root resorption is a rare remodeling process that can be studied using different experimental methods.