introduction: the aim of the present study was to evaluate the effect of glass ceramic insert in the sandwich technique to reduce microleakage in class ii composite resin restorations. methods: sixty sound human upper second premolars were selected and randomly divided into six groups (n=10). class ii box-only cavities were prepared in distal aspects of each tooth with gingival margin located a...

We study the minimal complexity of tilings of a plane with a given tile set. We note that any tile set admits either no tiling or some tiling with O(n) Kolmogorov complexity of its (n× n)squares. We construct tile sets for which this bound is tight: all (n × n)-squares in all tilings have complexity Ω(n). This adds a quantitative angle to classical results on non-recursivity of tilings – that w...

In this paper we explore the power of tile self-assembly models that extend the well-studied abstract Tile Assembly Model (aTAM) by permitting tiles of shapes beyond unit squares. Our main result shows the surprising fact that any aTAM system, consisting of many different tile types, can be simulated by a single tile type of a general shape. As a consequence, we obtain a single universal tile t...

Background and Aim: Bleaching can improve the color of restorative materials and resolve problems related to discoloration or color mismatch. This study evaluated the effect of in-office bleaching method in conjunction with two different laser wavelengths on color change of two types of glass-ionomer restorative materials (light-cure and self-cure). Materials and Methods: In this experimenta...