Hydroxyapatite is a biologically compatible material and a major component of dental enamel and bone tissue. Because of its biocompatibility and structural similarity to human teeth and the skeletal system, a number of dental studies have evaluated its application as a bone substitute or dental restorative material. This study was to evaluate the differences in bonding strength and resistance to demineralization between micro-hydroxyapatite and nano-hydroxyapatite added to self-cured resin-reinforced/modified glass ionomer cement. RelyX was used as the base glass ionomer cement material and for the control group. 10% micro-hydroxyapatite added glass ionomer cement was named experimental group 1, and 10% nano-hydroxyapatite added glass ionomer cement was named experimental group 2. Physical tests for ISO9917-1:2007 in each group was acceptable, except the setting time of nano-hydroxyapatite added glass ionomer cement, which exceeded maximum setting time. Bonding strength was greatest in nano-hydroxyapatite glass ionomer cement, and cohesive failure was common in all specimens. When fractured surface was observed under SEM, spherical particles were observed in experimental groups containing hydroxyapatite particles, and they were more prevalent in nano-HA added glass ionomer cement group than in micro-hydroxyapatite added group. Both experimental groups exhibited greater resistance to demineralization compared to the control group, and there was no significant difference between the experimental groups. Under SEM, nano-hydroxyapatite added glass ionomer cement exhibited increased resistance to demineralization compared to micro-hydroxyapatite added glass ionomer cement.

A new colorimetric test (Cariview � ) using a new type of pH indicator can reflect the acidogenic potential of plaque bacteria. The objective of this study was to evaluate the correlation between Cariview � and the caries experience (measured through the dmft index) of children, and to compare Cariview � with Dentocult SM � .Having obtained informed consent, 135 children less than 6 years old participated in the study. We examined their dmft index, and performed two caries activity tests (Cariview � and Dentocult SM � ) according to the manufacturers'instructions.In the results, Cariview � showed a moderate correlation with the dmft index (r = 0.43, p < 0.01). Cariview � showed a sensitivity of 68.8%, a specificity of 69.2%, and an area under curve of 0.686 in the ROC curve analysis. Cariview � had a significant correlation with the children' s caries experience and had a slightly better explanatory ability than Dentocult SM � . Furthermore, Cariview � was convenient and easy to use on uncooperative children, and also had an educational effect with its visual colors. It is suggested that Cariview � could be used clinically to identify the children susceptible to develop caries and to establish a preventive strategy.

The aim of this study was to assess the spacing and crowding of the anterior teeth in the primary dentition in Hwaseong city. Photographs of the anterior segment of 237 children satisfied the criteria. The presence of primate spaces and developmental spaces was assessed by the proximal contacts. Physiologic spacing was observed in 47.3% and 38.0% of the cases in the upper and lower arches, respectively. 43.5% showed the presence of two-segment contact or crowded dentition. Physiologic spacing was observed more in boys than in girls. In the maxilla, primate space was more frequent than developmental space; however, in the mandible, the difference was low. In the maxilla, the space between the central incisor and the lateral incisor was more frequent than the space between both central incisors. In contrast, in the mandible, the space between both central incisors was more common than the space between the central and lateral incisors or between the lateral incisors and canine. The present study describes the tendency for anterior spacing and crowding in the primary dentition. Further longitudinal studies with a larger sample are needed. Dentists should consider these concepts of spacing or contact/ crowding when performing full coronal restorations of primary anterior teeth.

Traditional method of pulpectomy for a necrotic primary anterior tooth was done on lingual side. But it could not recover the discoloration of crown effectively. For the purpose of treating the discoloration of crown after lingual pulpectomy, additional methods of crown restoration were needed like : celluloid crown, open-faced crown, rasin-faced crown. Neverthless, these kinds of complete coverage methods had some disadvantages such as possibility of tooth fracture by increased tooth preparation. In order to overcome the shortcomings of lingual pulpectomy, labial treatment could be considered as an alternative. It is a method that treats necrotic pulp through the labial access opening. After finishing the pulp treatment, discolored labial tooth structure was removed extending from access opening. Discoloration of deep area could be masked effectively using opaque sealant. Cavity on labial side was restored with composite resin. This labial approach method has several advantages. First, it gives a direct vision for effective pulp treatment which is also very useful for children with poor behavior. Second, most of lingual tooth structure could be saved and occlusal contact of lingual surface remains undisrupted. Only nonfunctional discolored labial surface may removed. Third, complete removal of discolored part of a labial tooth and immediate resin restoration could be done effectively after pulp treatment. Moreover, it also could be used for pulp treatment having serious dental caries on labial surface with sound lingual tooth structure. This report presents cases with discolored upper anteior primary tooth, approaching labial side with successful restoration. [J

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