Objective: The objective of this study was to evaluate in vitro the shear bond strength of two types of MIM (Metal Injection Molding) technology brackets, one with conventional mesh base and the other with rail-shaped mesh base. Materials and Methods: Forty human premolars received the bonding of 2 types of brackets: Group 1- 20 Synergy metal brackets (Rocky Mountain) with conventional mesh base and Group 2-20 H4 brackets (OrthoClassic) with rail-shaped mesh base. Both brackets were bonded with Resilience photopolymerizable resin (OrthoTechnology). The specimens were coupled to a Tinius Olsen universal test machine where the shear test was performed using a chisel. In addition, the amount of remaining resin in tooth crown with the ImageJ program was evaluated and the Adhesive Remnant Index (ARI). Intergroup comparison was performed by the independent t test and Chi-square test. Results: There was no statistically significant difference between the groups for any of the measures evaluated indicating that the mesh type of the brackets’ base with MIM technology did not influence the shear bond strength of the brackets (shear bond strength, p=0.191; maximum load registered, p=0.244). There was also no difference between the percentage (p=0.602) and area of remaining resin in the teeth (p=0.805) and IRA (p=0.625) between the Synergy and H4 groups. Conclusion: Shear bond strength was similar in the two types of brackets with MIM technology evaluated. In addition, the remaining resin in the dental enamel of two types of brackets were also similar.

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La anatomía del seno maxilar (SM) tiene una estrecha relación con las raíces dentales superiores, convirtiéndose en un reto para tratamientos endodónticos. El piso del seno maxilar esta recubierto por una fina capa cortical y por la membrana de Schneider, la cual puede llegar a ser perforada causando una comunicación endoantral. Las comunicaciones pueden ser visibles mediante el empleo de una Tomografía Computarizada de Haz Cónico (TCHC) que no permite visualizar diferentes planos para identificar la extensión de una lesión periapical o una iatrogenia. Por ello el objetivo de este estudio es establecer la proximidad entre las raíces dentarias del maxilar superior con respecto al seno maxilar (SM) con información de estudios ejecutados, empleando TCHC y su importancia en la rama de la endodoncia, en bases de datos como Pubmed, Google Scholar y ELSIERVER desde el año 2012 a 2022. Utilizando las siguientes palabras clave: Tomografía Computarizada de Haz Cónico, Endodoncia, Seno Maxilar, Raíz del Diente, Proximidad. Obteniendo 669 artículos científicos, los cuales 30 artículos cumplieron los criterios de inclusión y exclusión. Demostrando que la raíz mesiovestibular del segundo molar superior se encontró con mayor frecuencia dentro del piso del seno maxilar en la mayoría evaluaciones tomográficas. Concluyendo que para el estudio completo de la anatomía del PSM y su íntima relación con las raíces dentarias es importante implementar TCHC, que brinde información completa y tridimensional sobre la anatomía del PSM, ya que este puede extenderse hacia regiones anteriores, siendo más probable el riesgo de causar una comunicación endoantral.

Introduction: The extrusion of apical detritus during the retracting procedure is very important, as, besides eliminating materials of radicular obturation, aggressive agents and products such as the remains of dentin taken out, and microorganisms are generally located in tissue around the roots, producing undesired effects, such as inflammation, acute pain, post-operatory pain and delays in the periapical treatment. Objective: To determine the amount of apically extruded detritus using rotary and reciprocating retreatment systems. Methodology: An experimental comparative study as conducted in which 40 single-rooted human first premolars were analyzed. The instruments used were ProTaper Universal files up to F3 and sodium hypochlorite, and the sealing was made through the hybrid technique Tager. They were then kept at 37ºC and 100% of humidity for 15 days so that the sealing material would seal. For the retracting procedure, experimental tubes previously weighted were used. The sample was divided randomly into two groups of 20 pieces. Group A: ProTaper R, and group B: Reciproc. Then, the irrigating material (distilled water) was evaporated from the tubes for 12 hours in a stove at 105ºC, and the experimental tubes were weighted in an analytical precision weighing scale 10-5g. The data was analyzed through the T Student with a significance level of 5%. Results: Results indicated that groups A and B, retreatment with rotational ProTaper R and reciprocating retreatment system (Reciproc) showed a similar difference of initial and final weights, indicating similar apical extrusion of detritus. Conclusion: Both systems extruded a similar amount of detritus during the retreatment procedures.

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