Mehrdad Kahvand, Mostafa Vahedian, Mansoureh Hadadzadeh, Ali Saleh, Aida Mehdipour,
Volume 36, Issue 0 (5-2023)
Abstract
Background and Aims: One of the concerns of dentists is selecting a suitable brand of stainless steel crowns with maximum dimensional adaptation with primary teeth. The aim of this study was to compare the primary molar crown dimensions with that of two brands of stainless steel crowns (SSCs) in a sample of Iranian children.
Materials and Methods: In this study, 130 eligible children between 3 and 12 years (66 boys, 64 girls) were selected. After recording the demographic information, the mesiodistal, buccolingual and occluso-gingival dimensions of first (D) and second (E) primary molars were measured on dental casts and compared with the dimensions of KTR (MeiMeiMinBenjing, Benjing, China) and Shinghung (Shinhungcompany, Seoul, South Korea) SSCs. Data were assessed using chi-square test and Pearson correlation coefficient. P<0.05 was considered statistically significant.
Results: In this study, the most dimension matching of the teeth with that of SSCs were observed mesiodistally in upper D and lower D, buccolingualy in the upper D and lower D, and occluso-gingivaly in upper D and lower E. The most cases of mismatch in the mesiodistal dimensions of the teeth with that of SSCs were observed in the lower E and upper D. Also, the most cases of mismatch in the buccolingual dimension were found for upper E and lower E.
Conclusion: Both SSCs brands in this study showed significant dimensional adaptation with the primary teeth in Iranian children. The most dimensional adaptation was between KTR SSCs and maxillary primary molars, and between Shinhung SSCs and mandibular primary molars.
Elahe Soltanmohamadi Borujeni, Ali Bavi, Mohammad Aghaali, Ali Saleh, Aida Mehdipour,
Volume 37, Issue 0 (3-2024)
Abstract
Background and Aims: Strong bond between the ceramic brackets and ceramic veneers has an important role in cosmetic treatment. The purpose of this study was to investigate the effect of aging on the shear bond strength (SBS) of ceramic brackets bonded to zirconia after surface preparation by Neodymium-doped Yttrium Aluminum Garnet (Nd: YAG) laser or sandblasting with alumina.
Materials and Methods: This experimental study was conducted on 24 zirconia blocks and these blocks were randomly divided into two groups for surface preparation and each was sub-divided into three time intervals. Surface preparation was done by sandblasting with alumina: in SG1 (Immediately after sandblasting), SG2 (2 weeks after sandblasting), and SG3 (3 months after sandblasting) groups. For the Nd: YAG laser (1/5W, 20Hz, 10s) with non-contact mode: in LG4 (Immediately after laser), LG5 (2 weeks after laser), and LG6 (3 months after laser) groups. The ceramic brackets were bonded to the zirconia blocks. The SBS and adhesive remnant index (ARI) were evaluated and compared among test groups. Dara were analyzed using Mann Whitney test.
Results: There was no significant difference between the SBS of SG1 and LG4 (P=0.430), SG2 and LG5 (P=0.382) and SG3 and LG6 (P=0.326) groups. LG4 group showed the highest shear bond strength. After aging (2 weeks and 3 months), the laser groups showed higher SBS. There was no significant difference in the ARI between SG1 and LG4 (P=0.220), SG2 and LG5 (P=0.154), SG3 and LG6 (P=0.527) groups.
Conclusion: No significant difference was observed between the Nd: YAG laser and sandblasted groups in terms of SBS and ARI over time. Therefore, Nd: YAG laser could be used as a surface treamnet method in Zirconia crowns for bonding to ceramic brackets.
