Optical impressions assessment for overlay restorations with rubber dam: A clinical trial.

OBJECTIVE: The possibility of making impressions of teeth prepared with a rubber dam in place has been proposed; however, this requires trimming and rescanning the mesh, which has been described as a cause of accuracy loss. This study aims to clinically determine whether overlay restorations obtained from a scan with a rubber dam in place have equivalent marginal fit, contact points, and occlusal fit to the same type of restorations obtained from a scan without a rubber dam. MATERIAL AND METHODS: Thirty patients who underwent overlay restoration of a molar with at least one neighbouring tooth were selected. After tooth preparation, two scans were performed: one without a rubber dam and the other with a rubber dam. Restorations were randomly created from one scan or another. The marginal fit, interproximal contact points, and occlusal fit were evaluated clinically. Two meshes, with and without rubber dams, were also compared. RESULTS: No significant differences were observed in the clinical evaluation of the overlays made of the two meshes. The trueness of the mesh from the impression made with a rubber dam with respect to the mesh without a rubber dam was about 40 µm in the critical areas of the preparation (margins, intaglio, and interproximal contact points). CONCLUSIONS: The results of this study show that under the conditions performed and with the equipment used, there are no significant clinical differences between overlay restorations made from a scan with a rubber dam and those made from a scan without a rubber dam. CLINICAL SIGNIFICANCE: Scanning with a rubber dam in place may be a valid option for certain types of restorations under certain clinical conditions.

Strict versus Liberal Use of Sentinel Node Biopsy in Breast Cancer Surgery: Any Clinical Outcome Differences? A 20-Year Clinical Experience.

Introduction: As applied to early breast cancer (BC) patients, sentinel node biopsy (SNB) has undergone major changes over the years, especially concerning the widening of indication criteria or skipping systematic axillary lymph node dissection (ALND) after a positive SN. We aimed to ascertain whether a strict versus a more liberal use of SNB resulted in different clinical outcomes in our clinical experience. Methods: We studied consecutive BC patients undergoing SNB between January 1, 2000, and March 31, 2020. There were 1,587 patients and 1,634 SNB procedures. Cases were divided into two study groups: the "strict" SNB group (unifocal tumors up to 35 mm in which ALND was always performed for a positive SN, amounting to 1,183 SNBs), and the "liberal" SNB group (extended tumor size up to selected T3 cases, as well as multifocal or bilateral disease, and patients with previous contralateral BC, not always followed by ALND after a positive SN, amounting to 451 SNBs). Patients were closely followed up to the end of the study. Results: Clinico-pathological variables were strikingly different between study groups, with the liberal group showing a higher risk profile. Cox regression analysis for disease recurrence did not show significant differences in axillary, lymph node, or locoregional recurrence rates or distant relapse. There were no differences in survival between groups. Conclusion: It seems reasonable to adopt the liberal SNB approach, as the goal of surgical management in early BC patients must be attaining optimal locoregional disease control, no matter the differences in distant metastatic spread rates across different BC risk profiles.

Conformación de conductos radiculares con sistemas reciprocantes por alumnos de grado: estudio in vitro de la incidencia de fractura / Shaping root canals with reciprocating files by undergraduate students: an in vitro study of fracture frequency

Objetivos: En la práctica clínica, la separación de un instrumento rotatorio de níquel- titanio (NiTi) puede comprometer el resultado del tratamiento de conductos. Ningún estudio ha evaluado la incidencia de fractura de instrumentos reciprocantes cuando son utilizados en dientes humanos extraídos por operadores inexpertos. Por lo tanto, el objetivo de este estudio fue evaluar la incidencia de fractura de los instrumentos ProTaper Universal, WaveOne y Reciproc cuando son utilizados por operadores inexpertos en dientes extraídos. Metodología: Se instrumentaron 240 conductos mesiales de molares mandibulares (80 por grupo) con un ángulo de curvatura entre 20 y 45 grados, utilizando rotación continua (Grupo A: instrumentos ProTaper) y rotación reciprocante (grupo B: Reciproc, y grupo C: WaveOne). Todos los tratamientos de conductos fueron realizados por 120 operadores sin experiencia (estudiantes de tercer año de Odontología). Resultados: Durante la preparación de los 240 conductos curvos no se observó ninguna fractura en los Grupos B y C (Reciproc y WaveOne), mientras que en el Grupo A (ProTaper), se fracturaron 10 instrumentos rotatorio de Níquel Titanio. La prueba de Fisher reveló diferencias estadísticas con respecto a esta variable entre los grupos (p = 0,0001). Conclusiones: Según nuestros resultados los dos sistemas de lima única reciprocantes usados en este estudio son mas seguros que el sistema ProTaper

Purpose: In clinical practice, nickel-titanium (NiTi) rotary instrument separation can compromise the outcome of root canal treatment. No studies have assessed the incidence of fracture of reciprocating instruments when used on extracted human teeth by inexperienced operators. Therefore, the aim of this study was to evaluate the incidence of fracture of ProTaper, WaveOne, and Reciproc instruments when used by novice operators on extracted teeth. Methods: Instrumentation was performed on 240 mesial mandibular molar root canals (80 per group) with an angle of curvature ranged from 20 to 45 degrees using continuous rotation (group A: ProTaper instruments) and reciprocating rotation (group B: Reciproc, and group C: WaveOne instruments). Root canal treatments were performed by 120 inexperienced operators (third-year dental students). Results: During the preparation of the 240 curved of the mandibular no instrument fracture was observed in Groups B and C (Reciproc and WaveOne group), whereas 10 Ni-Ti rotary instruments fractured in Group A (ProTaper group). Fisher´s exact test revealed statistical differences with regard to this variable between the groups (p=0.0001). Conclusions: According to our results the 2 types of single-file reciprocating instrument systems used in this study are safer than ProTaper System