Shear Bond Strength Evaluation of Different Composites Used As Lingual Retainer Adhesives

The aim of this study was to determine the shear bond strength (SBS) levels and fracture modes of different composites used as lingual retainer adhesives. Sixty human mandibular incisors were used, that mounted in acrylic resin leaving the buccal surface of the crowns parallel to the base of the moulds. Randomly three groups were constructed, each containing 20 teeth. Transbond-LR (3M-Uni-tek), Transbond-XT (3M-Unitek) and Venus Flow (Heraeus Kulzer) were tested. Materials were applied to the teeth surface by packing the material into the cylindrical plastic matrices with a 2.34 mm internal diameter and a 3 mm height (Ultradent) to simulate the lingual retainer bonding. For SBS testing, the specimens were mounted in a universal testing machine, and an apparatus (Ultradent) attached to a compression load cell was applied to each of the specimen until the failure occurred. The SBS data were analyzed using analysis of variance and Tukey tests, and chi-square test was used to analyze the fracture modes. The statistical tests indicated that Transbond-LR shows statistically significant higher SBS (24.7±9.25 MPa) then Transbond-XT (12.01±4.98 MPa) and Venus Flow (14.07±5.25 MPa) (P<0.001) whereas the difference between Transbond-XT and Venus Flow was not significant. In general, a greater percentage of the fractures were adhesive at the tooth-composite interface (60%% for Transbond-LR and Venus Flow and 90°% for Transbond-XT) and no statistically significant difference was found between the groups. According to the results of this study, Transbond LR was found to be most appropriate material for the tested specification

Evaluation of Fit between Tooth and Band Surfaces when Different Orthodontic Cements are Used

The aim of this in vitro study was to compare three orthodontic band cements for gaps remained between tooth and band surfaces, at the cervical margin, which possibly caused after banding procedure. Sixty freshly extracted human mandibular third molars were randomly divided into 3 equal groups. Micro-etched molar bands were cemented to the teeth using each of the orthodontic band cements (Ketac Cem®, 3M Multi-Cure® and Transbond Plus®). The teeth were placed in preformed boxes (2.5X2.5X2.5 cm); crowns were on the bottom and perpendicular to the ground. Samples were capped with black colored plaster on a vibration machine. After hardening of the plasters, samples were removed from the boxes and were trimmed in the bucco-lingual dimension for evaluation. The mean of four parallel sections examined under a stere-omicroscope was noted as the score of that sample, for buccal and lingual sides, separately. Statistically analyses were performed by using analysis of variance and paired-samples t-test. When buccal and lingual gap formations were compared, Transbond Plus® and Ketac Cem® groups were found to have larger gaps in the lingual side than buccal at p<0.05 and p<0.01 level, respectively. Thus, buccal and lingual gaps of three cements were compared separately, and no statistically significant difference was determined among three investigated cement types at buccal and lingual sides. However no differences were found among different types of band cements, it is clear that large gaps were observed under molar bands at cervical margin; where it is not easily possible to clean. Further studies should be conducted to determine a favorable strategy to eliminate these gaps and maintain a gap-free adaptation and cementation between band and tooth structure

Effects of Functional Anterior Shifting On Skeletal and Airway Structures

To compare the maxillary and mandibular skeletal structures and airway dimensions between anterior functional shifting and Class I control patients. This study was composed of 48 patients. The first group was consisted of 24 patients (male: 11, female: 13). Mean ANB value was 0.31 ± 3.49 and mean age is 13.52 ± 2.95. The second group was a skeletal Class I group, and consisted of 24 patients (male: 7, female: 17) and served as the control group. Mean ANB was 2.47 ± 2.27 and mean age was 13.99 ± 1.79. Eighteen cephalometric measurements were used to evaluate skeletal differences, and 14 measurements were used for airway dimensions. Two groups were compared with independent t test. Position and size of the mandible were not affected with anterior functional shifting. S-Go distance was smaller in anterior functional shifting patients (p<0.05). Hard palate - soft palate angle was statistically lower (p< 0.01) and soft palate length (pns-spt) was higher (p<0.01) in anterior functional shifting group. Inferior airway measurement (sbti-phwl) represented higher values in functional anterior shifting group (p< 0.05). There were statistically significant differences in Pns-ppw1 (p< 0.05), spl/sps (p< 0.01) and spl/Ips (p< 0.01) measurements. Patients with anterior functional shifting showed wider airway than Class I control group. Postnatal maxillary development deficiency may be observed in functional anterior shifting cases

Farklı İskeletsel Malokluzyonların Üst Havayolu Boyutları Üzerine Etkileri

Kraniofasiyal iskeletsel morfoloji ve üst hava yolu boyutu arasındaki ilişki önemli bir tartışma konusudur. Bu retrospektif çalışmanın amacı iskeletsel Sınıf I, Sınıf II ve Sınıf III hastalar arasındaki nazofaringeal, orofaringeal ve hipofaringeal hava yolu boyutlarını lateral sefalometrik radyograflar kullanarak değerlendirmektir. Erciyes Üniversitesi Diş Hekimliği Fakültesi arşivinden elde edilen lateral sefalometrik radyograflar üzerinde, Sınıf I maloklüzyona sahip 30 hastanın (20 kız, 10 erkek), sınıf II maloklüzyona sahip 31 hastanın (20 kız, 11 erkek) ve sınıf III maloklüzyona sahip 29 hastanın (18 kız, 11 erkek) üst havayolu boyutları değerlendirilmiştir. Nazofaringeal hava yolu (PNS-UPW), orofaringeal hava yolu (U-MPW) ve hipofaringeal hava yolu (V-LPW) boyutları ölçülmüştür. Ayrıca dil uzunluğu, vertikal hava yolu uzunluğu, yumuşak damağın angulasyonu, uzunluğu, kalınlığı ve yüksekliği, alt ve üst faringeal boşluk miktarları ve mandibular düzleme göre hyoid kemiğin konumu değerlendirilmiştir. Elde edilen veriler istatistiksel olarak Tek Yönlü Varyans Analizi ve Fisher’ın LSD Testi kullanılarak karşılaştırılmıştır. Nazofaringeal havayolu (F­­=0,970, p=0,383), Orofarengial havayolu (F=1,34, p=0,267) ve Hipofaringeal havayolu (F=1,86,  p=0,161) boyutları arasında iskeletsel Sınıf I, Sınıf II ve Sınıf III maloklüzyona sahip hastalar arasında istatistiksel olarak anlamlı fark görülmemiştir. Ancak üst ve alt faringeal boşluk miktarları gruplar arasında istatistiksel olarak anlamlı fark göstermiştir. Sonuç olarak, nazofaringeal, orofarengial ve hipofaringeal havayolu boyutları iskeletsel Sınıf I, Sınıf II ve Sınıf III maloklüzyondan bağımsızdır