Effect of canal preparation with XP-endo Shaper and ProTaper Next on root canal geometry and dentin thickness of mandibular premolars with radicular grooves and two canals: a micro-CT study.

OBJECTIVES: This study aimed to evaluate the effects of different shaping protocols on the root canal geometry and remaining dentin thickness of mandibular premolars with radicular grooves (RG) and two canals by means of micro-CT. MATERIALS AND METHODS: Mandibular premolars with RG and two canals were matched based on their similar morphological dimensions and assigned to 2 experimental groups according to the canal preparation (n=8): XP-endo Shaper (XPS) and ProTaper Next (PTN) systems. Before and after preparation, morphometric measurements of the volume, surface area, structure model index, area, perimeter, roundness, major and minor diameters, as well as untouched canal walls, canal transportation, and dentin wall thickness were evaluated. Data were statistically compared within and between groups using the independent sample t test (α=5%). RESULTS: XPS revealed less changes in volume, surface area, area, perimeter, and major and minor diameters (P<0.05). There was no significant difference in structure model index (SMI), roundness, and percentage of untouched canal walls between groups (P>0.05). XPS resulted in less apical canal transportation and a higher remaining dentin thickness toward the RG compared to PTN in lingual canals (P<0.05). CONCLUSIONS: XPS revealed fewer changes in root canal geometry as well as lower transportation and a greater remaining dentin thickness in the lingual canals toward the RG compared to PTN. CLINICAL RELEVANCE: Internal and external anatomical characteristics of mandibular premolars might have an influence on biomechanical preparation. Considering the risk of perforation, the canal preparation using XPS appears to be more conservative compared to PTN.

Knowledge, Perception, and Experience of Dentists About Teledentistry.

OBJECTIVES: This study aimed to evaluate the level of knowledge, perception, and experience of teledentistry amongst Brazilian dentists with the ongoing COVID-19 pandemic. METHODS: Between June and July 2020, an online questionnaire was used to collect information on the demographic and professional profiles of dentists and their levels of knowledge, perception, and attitudes towards teledentistry. Descriptive statistics were reported as percentages, and Chi-squared test was used to compare responses amongst general practitioners, specialists, and those with varying levels of professional experience. RESULTS: This study included 575 dentists, the majority of whom were from the southeast region of Brazil (73.4%) and had a specialist degree (70.4%). Approximately 42.4% of the study sample had graduated more than 10 years ago, 39.3% between 2 and 10 years ago, and 18.3% up to 2 years ago. In general, the majority of dentists exhibited only a superficial awareness of the resolution that regulates teledentistry in Brazil. A greater number of specialists were aware of the resolution (P = .007) and felt confident performing teledentistry (P = .000) compared to general practitioners, whilst those with more experience (graduated more than 10 years ago) exhibited greater knowledge (P = .012) and preparation (P = .000). More than 60% of the dentists, regardless of dental specialty and clinical experience, had no knowledge of providing prescriptions via teledentistry. The majority of general practitioners (89.5%) and specialists (81.4%) had no previous experience using teledentistry. CONCLUSIONS: The findings of this study suggest that Brazilian dentists are inadequately prepared for the implementation of teledentistry.

Comparação da fragilidade gerada por 3 diferentes osteotomias sagitais de mandíbula: estudo in vitro / Comparison of fragility generated by 3 different sagittal mandible osteotomies: in vitro study / Comparación de la fragilidad generada por 3 osteotomías mandibulares sagitales diferentes: estudio in vitro

A osteotomia sagital bilateral de mandíbula (OSBM) foi publicada por Trauner e Obwegeser em 1957, desde então sofreu várias modificações a fim de diminuir as complicações e tornar o procedimento mais simples e previsível. Sendo assim objetivo do presente trabalho foi avaliar e comparar a fragilidade causada na mandíbula por 3 tipos de OSBM. Para isso, foram realizadas as osteotomias propostas por Trauner e Obwegeser modificada por Hunsuck e Epker (I), a de Sant'Ana (II) e de Wolford (III), em 24 hemimandibulas de poliuretano e foi realizado o ensaio mecânico para gerar a fratura sagital. Os dados foram coletados e tabulados, e obteve como resultado que, a maior quantidade de força máxima aplicada foi observada no grupo III, e a menor quantidade no grupo II; com relação à deflexão, apresentou significância estatística entre o grupo II e grupo III; com relação à rigidez, a maior média, foi encontrada no grupo I. Sendo assim, foi possível concluir que dentro deste modelo de estudo a osteotomia II foi capaz de gerar maior fragilidade à hemimandibula de poliuretano com menor quantidade de força. As OBMD dos grupos I e a III também apresentaram ótimos resultados, entretanto necessitaram mais força para alcançar a fratura... (AU)

The bilateral sagittal split osteotomy of the mandible (BSSO) was published by Trauner and Obwegeser in 1957, since then it has undergone several modifications in order to reduce complications and make the procedure simpler and more predictable. Therefore, the objective of this study was to evaluate and compare the fragility caused in the mandible by 3 types of BSSO. For this, the osteotomies proposed by Trauner and Obwegeser modified by Hunsuck and Epker (I), Sant'Ana (II) and Wolford (III) were performed on 24 polyuretha ne hemimandibles, a mechanical test to generate the sagittal fracture. Data were collected and tabulated, and the result was that, the highest amount of maximum force applied was observed in group III, and the lowest amount in group II; with regard to deflection, it was statistically significant between group II and group III; with regard to stiffness, the highest average was found in group I. Therefore, it was possible to conclude that within this study model, osteotomy II was able to generate greater fragility to the polyurethane hemimandible with less force. The BSSO of the groups I and III also showed excelent results, however they required more force to reach the fracture... (AU)

La osteotomía sagital bilateral de la mandíbula (OSBM) fue publicada por Trauner y Obwegeser en 1957, desde entonces ha sufrido varias modificaciones con el fin de reducir las complicaciones y hacer el procedimiento más simple y predecible. Por lo tanto, el objetivo de este estudio fue evaluar y comparar la fragilidad causada en la mandíbula por 3 tipos de OSBM. Para eso, se realizaron las osteotomías propuestas por Trauner y Obwegeser modificadas por Hunsuck y Epker (I), Sant'Ana (II) y Wolford (III) en 24 hemimandíbulas de poliuretano y se realizó un ensayo mecánico para generar la fractura sagital. Los datos fueron recolectados y tabulados, obteniendo como resultado que, la mayor cantidad de fuerza máxima aplicada se observó en el grupo III, y la menor cantidad en el grupo II; en cuanto a la deflexión, fue estadísticamente significativa entre el grupo II y el grupo III; en cuanto a la rigidez, la media más alta se encontró en el grupo I. Por lo tanto, se pudo concluir que, dentro de este modelo de estudio, la osteotomía II logró generar mayor fragilidad a la hemimandíbula de poliuretano con menor fuerza. El OSBM de los grupos I y III también mostró excelentes resultados, pero requirieron mayor fuerza para llegar a la fractura... (AU)