ABSTRACT
Preventing enamel demineralization around brackets is a concern for orthodontists. Fluoride releasing materials have been recommended to overcome this problem. The aim of this study was to evaluate the effect of incorporating nanohydroxyapatite [NHA] into resin modified glass ionomer cements [RMGIC] on ceramic bracket debonding. In this experimental study, 80 human premolars were divided into 4 bonding groups as follows: group 1: Transbond XT [TBXT] [control group], group 2: Fuji II LC [RMGIC], group 3: 5% NHA added to RMGIC and group 4 10% NHA added to RMGIC. After enamel etching, ceramic brackets were bonded. The shear bond strength [SBS] and the adhesive remnant index [ARI] were calculated for each group. The data were analyzed using one-way ANOVA, Tukey's post hoc HSD test and the Kruskal Wallis test. According to ANOVA, 10% NHA added to RMGIC had a significantly lower SBS compared to other groups [11.93 +/- 2.11] but no significant difference was found among the remaining groups. The mean SBS was 17.33 +/- 4.07 MPa in group 1, 17.22 +/- 3.55 MPa in group 2 and 16.56 +/- 2.59 MPa in group 3. According to ARI, the predominant failure mode in RMGIC groups was cohesive. Resin modified glass ionomer cements containing 5% NHA can be as effective as composite resins for bonding ceramic brackets
ABSTRACT
Hypodontia [Congenital tooth agenesis] is the most common developmental dental anomalies in children. As the lack of teeth can cause psychological, aesthetic, and functional problems, knowledge on prevalence of hypodontia could help in diagnosis and prevention of associated complications. This study was performed to determine the prevalence of hypodontia among high school students in Qazvin. This was a descriptive cross-sectional study carried out on 2619 high school students of both sexes in Qazvin during 2006-2007. The frequency of hypodontia without considering the third molars in high school children and also the association between the tooth type, sex, upper or lower arch, and the affected side were investigated using interviews, oral study, and cast and panoramic radiographic examinations. An overall hypodontia frequency of 7.4% was found for the total samples with 7.6% and 7.2% in males and females, respectively. The most frequent missing teeth were the maxillary lateral incisors, mandibular, and maxillary second premolars, respectively. There was no statistically significant difference between the sexes [p > 0.05]. A higher incidence of missing teeth was observed in maxillary arch compared to mandibular and on the left side rather than the right side [P < 0.001]. The prevalence of hypodontia regardless of third molars was 7.4% among the high school students in Qazvin, a finding consistent with those reported for European countries. The prevalence of this complication was found to be higher among girls yet the difference was insignificant, statistically
Subject(s)
Humans , Male , Female , Tooth , Students , Incisor , Bicuspid , Cross-Sectional StudiesABSTRACT
Introduction: using template is a very fast and reliable way for diagnosing and treatment planning in orthodontics. The aim of this study, which was done for the first time in Iran, was to prepare lateral and frontal cephalometric templates for men with normal occlusion to be used for diagnosis and treatment planning of patients who need orthodontic and ortho-surgical services
Materials and Methods: 31 male students of Islamic Azad University with normal occlusion, aged 19 to 25 with the mean age of 21.3 years, were selected. After preparing files and taking impressions, lateral and frontal cephalograms were taken in NHP and cephalometric analyses were done. Data were analyzed using SOSS software [Student t-test]
Results: 2 templates were extracted, one lateral and one frontal or posterio-frontal
Conclusion: using template is a very fast and reliable way for diagnosis and treatment planning in orthodontics. The templates of this study, which are available and will be submitted on request, can be used for patients of the above-mentioned age group