Articulators are instruments that aimed to reproduce the range of jaw movements. The first instrument designs were attempts to duplicate anatomic relations or reproduce functional movements of the anatomy. They were able to preserve centric position only. More sophisticated articulating instruments evolved as more was learned about the anatomy, mandibular movements, and mechanical principles. Over time, interest for articulators progressed. Articulators became adjustable, and they attempted to reproduce jaw movements of each patient by reproducing the anatomy of temporomandibular joints (TMJ's) and related structures. Part I of the article has discussed evolution of articulators beginning from the 18 th century till 1940. A history of articulators from 1940 till today is discussed in the present article.

t is of interest to synthesize Nano eggshell-titanium-dioxide (EB@TiO2) biocomposite and to evaluate its effectiveness in occluding opened dentine tubules. EB@TiO2 was synthesized and characterized using X-ray diffraction (XRD), and Transmission Electron Microscope (TEM). Sixteen simulated bovine dentine discs were prepared and randomly assigned into four groups according to the following treatment (n = 4): Group 1: No treatment; Group 2: eggshell powder; Group 3: EB@TiO2; and Group 4: GIC mousse. These were then, agitated in a solution of 1g powder and 40mL water for 3hours. Thereafter, each dentine discs from the respective groups were post-treated for 5 min with 2wt% citric acid to test their acid resistant characteristics. Scanning Electron Microscope (SEM) was used to observe the effectiveness of occluded dentine pre-treatment and post-treatment. The cytotoxicity of the synthesized EB@TiO2 was tested using NIH 3T3 assay. ANOVA was used to evaluate the mean values of the occluded area ratio and the data of MTS assay. This was followed by a multi-comparison test with Bonferroni correction (α = .05). The XRD confirmed that EB@TiO2 was successfully modified through ball-milling. The TEM revealed the presence of both spherical and irregular particle shape powders. The SEM result showed that EB@TiO2 could effectively occlude open dentine tubules. Equally, the result demonstrated that EB@TiO2 exhibited the highest acid resistant stability post-treatment. NIH 3T3 assay identified that EB@TiO2 had little effect on the NIH 3T3 cell line even at the highest concentration of 100μg/ml. This study suggests that the application of EB@TiO2 effectively occluded dentine tubules and the occlusion showed a high acid resistant stability.

Summary One of the objectives of prosthetic dentistry is to restore teeth in harmony with temporo-mandibular joints. Articulator is a device that allows an operator to fabricate a restoration that will be physiologically and psychologically successful. But how much do we really know about the origin of articulators? First articulator designs attempted to duplicate anatomic relationships and functional movements. More sophisticated articulators evolved as more new knowledge about anatomy, mandibular movements and mechanical principles were obtained. The aim of this article was to describe the origin, history and evolution of articulators through the years. For this article, an electronic search was performed across three databases (Science Direct, PubMed and Google Scholar) for relevant citations. Keywords such as articulators, history, early articulators were used alone and in combination for the search. The option of “related articles” was also utilized. Finally, search was performed on the review articles and the most relevant papers were selected.

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