Abstract : This study aimed to identify the root and root canal morphology of maxillary first (P1) and second (P2) premolars in Japanese patients using computed tomography (CT). The subjects were 200 Japanese individuals (100 males, 100 females) who had undergone CT for investigation of oral pathologies in the Department of Radiology at our hospital. For all subjects, one root was present in about 80% of P1 and >90% of P2. Using Turner's classification, one root and one apex were observed in about 50% of P1 and >90% of P2 in both sexes. P2 never showed a complex root in females, but two complex roots were observed in males. P1 predominantly (about 83%) showed two root canals, however, P2 predominantly (about 70%) showed one root canal. In addition, two root canals were more frequent in P1 than in P2 in both sexes (p<0.01). Using Vertucci's classification of the anatomy of one root in P1 and P2, two root canals in P1 were mostly Type Ⅳ (two root canals did not join in the morphology of two root canals and two apical foramina) or Type Ⅱ (two root canals joined in the morphology of one root canal and one apical foramen).
Resilience is the capacity to cope with stress, characterized as an activation process that protects one from psychological damage in adapting to personal and situational changes. Resilience is related to emotional processes including the attentional system and has been studied with spatial attention tasks. However, the relationship between resilience traits and temporal attention to emotional stimuli has not been studied. We investigated this relationship using an attentional blink (AB) paradigm. Observers searched two target upright faces (T1 and T2) inserted in a rapid serial visual presentation (RSVP) stream of inverted pictorial faces. The T1 and T2 tasks involved gender judgment and facial expressions (neutral, anger, and happy) judgment, respectively. A multivariate regression analysis showed that resilience scale score significantly predicted AB magnitude in response to negative stimuli, suggesting that resilience is related to temporary attentional bias toward negative information within a second.