Journal of Dental Medicine

Background and Aim: Several biomaterials have been presented for regeneration of intraosseous defects and Bio-Oss is one of the most accepted materials in this field. Neo-Oss may be the first and only regenerative material made in Iran which few studies have been published about it. The aim of this study was the histologic evaluation of Neo-Oss in comparison with Bio-Oss in experimental rabbit calvarial defects. Materials and Methods: This was an interventional in vivo study. After elevating muccoperiosteal flap 18 standard defects (3×6mm) in frontal & parietal bone were made by round bur on the calvarium of 6 New Zealand rabbits. Defects were randomly assigned to one of the following treatments: 1-No graft (control), 2-Bio-Oss graft 3-Neo-Oss graft. After 4 weeks the animals were killed and histologic sections prepared. The studied variables consisted of inflammation, type of regenerated bone, thickness of bony trabeculation and foreign body reaction. Data were analyzed by Friedman test with p<0.05 as the limit of significance.

Results: The results showed that Bio-Oss was effective for bone regeneration. Inflammation (P= 0.026) and foreign body reaction (P= 0.002) in Neo-Oss was significantly more than Bio-Oss group. Thickness of terabecula in Neo-Oss group (66.7% thin) was significantly different from Bio-Oss (100% thick) and control group (50% thin 50% thick) (P= 0.006). In Neo-Oss group, granulation tissue containing giant cells was observed and the rate of resorption during 4 weeks was high.

Conclusion: Based on the results of this study, the healing capacity of Neo-Oss in comparison with Bio-Oss is not acceptable.

Background and Aim: Achieving appropriate seal in canal obturation is the main goal of endodontic therapy. However, in some cases, it can not be obtained by non-surgical procedures alone. Retrograde surgery is one of the most common procedures in endodontics. Apical seal improvement can be obtained by root end filling and decreasing the root end resection angle (bevel angle). The aim of this study was to investigate the role of bevel angle on apical microleakage following the use of amalgam and MTA as root end filling materials.

Materials and Methods: In this experimental study, 128 extracted human teeth were instrumented and obturated by lateral condensation technique. The teeth were divided into two groups and the apical root resection was performed by high speed fissure bur (one group perpendicular to the long axis of the teeth and the other 45 to the long axis. The 3 mm root end cavity was prepared by ultrasonic device. Each group was divided into two subgroups: One filled with amalgam and the other with MTA. Teeth were incubated for 72 h, covered by two layers of nail polish (except for apical 3mm) and submerged in methylene blue for 48 h. Teeth were washed under tap water and mesiodistally dissected by low speed disc. Dye penetration was evaluated by stereomicroscope. Data were analysed by two way ANOVA and Tukey tests with p<0.05 as the limit of significance.

Results: The results showed that retrofill material type had a significant effect on microleakage and MTA was superior to amalgam in this respect. Bevel angle failed to show any significant effect on apical microleakage.

Conclusion: Based on the results of this study, it seems that the use of MTA instead of amalgam in clinical practice can improve the success rate of endodontic surgery whereas the bevel angle can be determined based on the status of each individual case However, increasing the bevel angle seems to increase microleakage due to exposure of more dentinal tubules.

Odontomas are benign tumors of odontogenic origin characterized by their slow growth. They are considered to be a common type of odontogenic tumor, but rarely occur in the primary dentition.The etiology of odontomas is unknown, although local trauma, infection and genetic factors have been suggested. Odontomas often cause disturbances in the eruption of teeth such as, impaction or delayed eruption, and retention of primary teeth and abnormalities in the position of teeth such as tipping or displacement of adjacent teeth. In this paper, a case of unerupted right mandibular primary cuspid in a 5 years old girl due to the presence of a compound odontoma is presented.