High prevalence of severe dental anxiety may be seen in early years of school. It seems that general factors such as family factors have less impact on behavior of school aged children in a dental visit.

Background and aims. One of the most common reasons forthe inferior alveolar nerve block anesthesia failure is the variation in mandibular foramen location. The aim of this study was to assess the location of mandibular foramen in children with mandibular retrognathism in comparison to children with normal skeletal occlusion in the mixed dentition.Materials and methods. One hundred and twenty panoramic radiographs of patients in mixed dentition period, undergoing orthodontic treatment, were selected based on inclusion criteria, skeletal occlusion and stage of dental development. The radiographs were divided into two groups: I: 60 panoramic radiographs of patients with normal skeletal occlusion (15 in each of the Hellman dental age stages); II: 60 panoramic radiographs of patients with mandibular retrognathism (15 in each of the Hellman dental age stages). The radiographs were traced and the linear distance from the mandibular foramen to the borders of the mandibular ramus and its angular position were identified. The measurements were compared between the two groups and among the four dental age groups by t-test, ANOVA and post hoc tests.Results. No statistically significant differences werefound between the patients with normal skeletal occlusion and patients with mandibular retrognathism (P>0.05). Statistical tests showed significant differences in the vertical location of mandibular foramen and gonial angle between the four dental age groups (P<0.05).Conclusion. Mandibular retrognathism does not have a significant impact on the location of the mandibular foramen in the mixed dentition period. The child’s dental age would be considered in the localization of the mandibular foramen.

Background and Aim: Restoration of primary anterior teeth with severe caries extending to the gingival margin is challenging for many clinicians especially in uncooperative children. Resin modified glass ionomer cements (RMGICs) can be suitable for use in such cases since they require fewer application steps than composite resins. This study aimed to assess the fracture strength of severely damaged primary anterior teeth after their coronal build-up using RMGIC and composite resin. Materials and Methods: This in vitro, experimental study was conducted on 40 primary teeth that met our inclusion criteria. After decoronization, they were cleaned and root canals were filled. In the coronal cavity, one layer of base was applied and an undercut was created in the canal wall above the base. The teeth were divided into two groups of 20 for coronal restoration. In group 1, etching, bonding, intracanal post fabrication and restoration with composite resin were carried out. In group 2, conditioning, intracanal post fabrication and restoration with Fuji II LC RMGIC were performed. After thermal cycles, fracture strength of teeth was measured and compared in the two groups using t-test. Results: Fracture strength of teeth was not significantly different between two groups restored with composite resin (5.03±2.30 MPa) and RMGIC (5.67±2.38 MPa) (P>0.05) Conclusion: In the post and crown build up of severely damaged primary anterior teeth with severe caries extending to the gingival margin, Fuji II LC RMGIC can be used as an alternative to composite resin especially in uncooperative children or treatment under general anesthesia.

Introduction: One of the main applications of laser in dentistry is the removal of dental caries and preparation of restorative cavities. The morphology and wettability of laser prepared surfaces are different from that of those prepared with conventional method which may affect the quality of the adhesive potential of bonding agents in these surfaces. This study aimed to assess the shear bond strength of a total-etch and self-etch adhesive system to primary tooth dentin prepared by two different energy densities of Er:YAG laser in comparison with surfaces prepared by bur. Methods: A total of 60 human primary second molars extracted for orthodontic purposes were selected and randomly divided into 3 main groups of equal (n = 20). Group A: Preparation of dentin surface by bur; group B: Preparation of dentin surface by laser with 300 mJ energy level; group C: Preparation of dentin surface by laser with 400 mJ energy level. In each of the main groups, the teeth were randomly assigned to 2 subgroups. Composite resin material was bonded with the total-etch adhesive system in subgroups A1, B1, and C1 and with the self-etch adhesive system in subgroups A2, B2, and C2. The samples were thermo-cycled, and composite restorations shear bond strength was measured in MPa. Data were analyzed using two-way analysis of variance (ANOVA), and P values less than 0.05 were considered statistically significant. Results: The highest and the lowest shear bond strength values were observed in group A2 (Preparation by bur-Composite resin material bonded by Clearfil SE Bond) and group C2 (Preparation by laser with 400 mJ energy level -Composite resin material bonded by Clearfil SE Bond), respectively. The results showed no statistically significant differences between the study subgroups (P > 0.05). Conclusion: It is concluded that in terms of shear bond strength to dentin, Single Bond and Clearfil SE Bond adhesive agents adequately perform in primary tooth dentin prepared by Er: YAG laser with energy levels of 300 and 400 mJ and frequency of 10 Hz.

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