When luting indirect restorations with dual-cure resin cement (DCRC), excess cement can be easily removed by performing tack cure of DCRC for a few seconds. The purpose of this study was to evaluate whether different tack cure times affect polymerization shrinkage (PS) of the selected DCRC. One dual-cure resin cement (G-CEM LinkAce, GC) was used for measuring PS in light-cure (LC group), self-cure (SC group), and two tack-cure modes. In the first tack-cure subgroup, tack cure was performed for 1, 2, 3, and 5 seconds, followed by light cure after 2 minutes of remnant removal time in each case (TC-LC groups). In the other tack-cure subgroup, tack cure was performed for the same lengths of time, but followed by self-cure in each case (TC-SC groups). PS was measured by a modified bonded disc method for 1,800 seconds. One-way analysis of variance followed by Duncan’s post hoc test was used to determine any statistically significant differences among the test groups (α = 0.05). When the DCRC was selfcured after tack cure, PS was significantly lower than when it was only self-cured (p < 0.05); however, tack cure time did not affect PS (p > 0.05). When the DCRC was light-cured, PS was not affected by tack cure or tack cure time (p > 0.05). Therefore, tack cure within 5 seconds did not negatively affect the final PS when the DCRC was light-cured after cement remnant removal.

The presence of the microorganisms of untreated canals is one of the main reasons of the failure in the endodontic treatment. The knowledge of variations in the canal systems of the tooth is important for the successful endodontic treatment. In the maxillary molars, the presence of the two separate palatal roots is very rare variations. Although there have been several case reports of maxillary first and second molars, the case reports of maxillary third molars are very few. This case report presents the endodontic treatment of a maxillary third molar with two separate palatal roots. It is important to notice the clinical signs and analyze the radiographs carefully. The use of a microscope is helpful for the visualization of pulpal chamber, and pulpal chamber floor should be investigated thoroughly with endodontic explorer. The straight-line access for all the canal orifices is important for the success in the endodontic trea

External root resorption is one of the rare pathological condition of tooth. It is occurred when periodontal ligament or cementum on the root surface are either damaged or denuded. The causes and classifications have been variously described. Because of the various causes and patterns, and absence of sufficient and consistent evidence for treatment, proper diagnosis and treatment plan based on clinician’s experience and close communication with patient is important. This case report represents the rare case of external root resorption and the treatment. The tooth was retained functionally in oral cavity showing good healing state in 2-year follow-up.