a. shaker

The Daraloo ore deposit area, structurally located in the Central Iran and Urumieh Dokhtar magmatic belt, is situated in the south of Kerman Province. In this region, Eocene andesitic flows and pyroclastic rocks have been invaded by Oligo-Miocene hypabyssal intrusive bodies. Most of the intrusive samples are granodiorite porphyry to monzogranite porphyry with a microgranular groundmass and affected by severe phyllic alteration. Mineralogical and geochemical evidence show that Daraloo granitic rocks are calc-alkaline, metaluminous to slightly peraluminous and I-type in nature. Clear negative Nb-Ti anomalies in most samples can be explained by the fractionation of titanium-containing phases such as titanite and titanomagnetite. Also, obvious enrichment in the large ion lithophile elements (LILEs such as K, Rb, Ba and Cs) and light rare earth elements (LREEs) compared to high field strength elements (HFSEs such as Ta, Nb, Ti and Zr) and heavy rare earth elements (HREEs), all clearly show a geochemical feature of magmas generated in subduction environments. So, it can be concluded that Daraloo granitic rocks must be formed in an active continental margin environment as a result of subduction of the Neotethys oceanic crust beneath the Central Iranian microcontinent during the Tertiary time.

Fissure sealant is the most effective method to prevent occlusal surface caries of posterior teeth. In recent years, the use of laser for enamel surface pretreatment has been considered as an effective method before applying fissure sealant. Hence, the aim of this study was to investigate the effect of Er:YAG laser conditioning on fissure sealant microleakage.

In this experimental study, total of 60 extracted third molars were randomly assigned into four groups(n=15). The occlusal surfaces were sealed with a sealant (clinpro) after one of the following pretreatments: 1- Phosphoric acid etching + total etch bonding, 2- Laser + self etch bonding, 3- Laser + total etch bonding, 4- Laser + Phosphoric acid etching + total etch bonding. The parameters of used laser was 120 mj energy and pulse duration of 250-500 µs with frequency 4 Hz. After sealing, the teeth were thermocycled at 500 cycles and immersed in methylen blue 1% for 24 hours. The teeth were then sectioned buccolingually and examined for microleakage. Statistical analysis were preformed via applying Kruskal-Wallis and Mann-Whitney.

The study results indicated significant differences between 4 groups (p<0.05) except for groups 1 and 4 (p=0.3). Moreover, the highest microleakage was observed in group 3, whereas the lowest was reported in group 4.

It seems that conventional acid etching technique is the best and simplest method of Sealant therapy.