Assessment of a new infrared laser transillumination technology (808 nm) for the detection of occlusal caries-an in vitro study.

This study aimed to evaluate in vitro performance of near-infrared laser transillumination (NIR-LTI) for detecting early occlusal caries in permanent teeth and compare it with quantitative light-induced fluorescence (QLF), DIAGNOdent Pen (DDPen), and conventional radiography (CR). Ninety-four occlusal surfaces presenting International Caries Detection and Assessment System (ICDAS) scores ranging from 0 to 3 were selected. For the NIR-LTI examination, images were captured using a prototype, which consists of a laser beam (808 nm) and an infrared CCD camera. One occlusal site on each tooth was assessed twice by two examiners. The teeth were prepared histologically and assessed for the presence of early caries. The intraexaminer correlation showed no difference between the NIR-LTI, DDPen, and QLF analytical methods, but all these methods differed from CR. Interexaminer reproducibility was moderate for NIR-LTI, which showed sensitivity (0.68), specificity (0.85), accuracy (0.73), and area under the receiver-operating characteristic (ROC) curve (0.76) similar to those of the fluorescence method and different from those of the CR. In conclusion, the performance of NIR-LTI was comparable to that of DDPen and QLF and may therefore be considered a valid and reliable alternative for the diagnosis of incipient lesions on the occlusal surface of permanent teeth.

Observation of ultracold ground-state heteronuclear molecules.

We report the observation of translationally ultracold heteronuclear ground-state molecules in a two-species magneto-optical trap containing 39K and 85Rb atoms. The KRb molecules are produced via photoassociation and detected by multiphoton ionization. We had characterized their temperature and measured their formation rate constant. We believe that the two-species trap could be used as a reliable source of ultracold molecules to be captured by electrostatic, magnetic, or optical traps. This possibility will certainly motivate further investigation of quantum collective effects as well as high-resolution spectroscopy of the rovibrational level structure of cold heteronuclear molecular systems.

Rydberg cold collisions dominated by ultralong range potential.

In this work we measure the time evolution of the population resulting from energy-transfer collisions as a function of the energy difference between the entrance and exit collisional channels using a sample of cold Rydberg atoms produced in a rubidium magneto-optical trap. The 34S(1/2) population, produced by collisions between atoms in the 33P(3/2) state, is monitored as a function of time through the pulsed-field ionization technique. The experimental results are compared with a recent published model based on a two-body interaction considering an attractive potential [Phys. Rev. A 65, 023405 (2002)]]; which is calculated according to a recent Letter by Boisseau et al. [Phys. Rev. Lett. 88, 133004 (2002)]]. The agreement is remarkable, which suggests the existence of such ultralong range potential proposed by Boisseau et al.