Transfer Accuracy of Three Indirect Bonding Trays: An In Vitro Study with 3D Scanned Models

Objective:The goal of the current study is to compare the transfer accuracy of two different conventional indirect bonding trays with 3D-printed trays.Methods:Twenty-two patients’ upper dental models were duplicated, scanned and brackets were bonded digitally. Different indirect bonding trays (double vacuum formed, transparent silicone and 3D-printed) were prepared according to three groups. These trays were used for the transfer of the brackets to the patients’ models, then models with brackets were scanned. GOM Inspect software was used for the superimposition of virtual bracket setups and models with brackets. A total of 788 brackets and tubes were analyzed. Transfer accuracies were determined according to the clinical limit of 0.5 mm for linear and 2° for angular measurements.Results:3D-printed trays had significantly lower linear deviation values than other trays for all planes (p<0.05). 3D-printed trays have significantly lower torque and tip deviation values than other groups (p<0.05). Transfer deviations were within the clinically acceptable limit for all transfer trays in horizontal, vertical and transverse planes. Deviation values of the molars were higher than those of the other tooth groups for all trays in the horizontal and vertical planes (p<0.05). Brackets were generally deviated toward the buccal direction in all tray groups.Conclusion:The transfer accuracy of 3D-printed transfer trays was more successful than the double vacuum formed and transparent silicone trays in the indirect bonding technique procedure. Deviations in the molar group were greater than those in the other tooth groups for all transfer trays

Comparison of the initial levelling efficiency of two different self-ligating brackets

Aim: The objective of this study, to evaluate the initial alignment effectiveness of two different passive self-ligating brackets (SLBs) and to compare the differences in arch widths. Materials and Methods: The patients with no skeletal discrepancy, Little’s irregularity index (LII) greater than 3 mm on both arches, who were treated with SLBs and whom had undamaged plaster models at the beginning (T0), 10th week (T1), and 20th week (T2) of their treatment period were enrolled to the study group. Group 1 (Damon) was consisted of 17 patients (mean age=14.5 years) and Group 2 (SmartClip) was consisted of 18 patients (mean age=13.6 years). The analogue dental casts were transferred to a digital model by scanning. Maxillary and mandibular intercanine, intermolar widths and LII were measured by MeshLab software. Wilcoxon signed-rank and Mann Whitney U tests was used for statistical evaluation. Results: There were no significant differences between the groups for the mean LII in T0 (maxillary LII, Group 1= 6.59 mm; Group 2= 6.32 mm; mandibular LII, Group 1= 5.95 mm, Group 2= 5.73mm). The rate of decrease in the LII between T0-T2 and between T1-T2 were found to be significantly higher for Group 1 in the mandible but there was no significant difference between T0-T1 (P= 0.031, P= 0.042, P= 0.113). There was no significant difference for the rate of decrease in the LIIs between the groups in the maxilla. When changes of intermolar and intercanine widths were compared according to the follow-up times, no significant differences were found for the treatment groups. Conclusion: Both SLBs groups were effective for reducing the crowding in maxillary arch. The increases in intercanine and intermolar widths were found to be similar for both groups. Group 1 was found to be better in the speed of the resolution of the crowding only in the lower incisor region

Cephalometric Mandibular Dimensions in Growing Turkish Children: Trends of Change, Sex-Specific Differences, and Comparisons with Published Norms

Objective: The aims of this study were to investigate cephalometric mandibular dimensions in growing Anatolian Turkish children and to identify the periods of rapid growth for boys and girls. Furthermore, the secondary aim was to compare obtained values with published standards in the literature.Methods: A total of 528 pretreatment lateral cephalometric radiographs, grouped according to age and sex, were analyzed. Effective mandibular length, ramus height, and corpus lengths were comparatively evaluated within age groups for boys and girls and between sexes for the same age group. Data acquired from this study were compared with American, Canadian, Chinese, and European norms. Growth curves for mandible were constructed for each sex group.Results: Effective mandibular length was almost always significantly longer in boys, except for 9- and 12-year-age groups. Effective mandibular length in girls increased significantly between ages 8 and 10, 10 and 12, and 11 and 13 years, while in boys between ages 8 and 10, 9 and 11, and 13 and 15 years. Turkish girls had significantly shorter effective mandibular lengths than American girls at age 14. No significant difference was found between Turkish and Chinese girls and boys. Turkish girls and boys had significantly shorter corpus lengths from their Norwegian counterparts at age 12.Conclusion: Except for 9- and 12-year-age groups, effective mandibular length was almost always significantly longer in boys compared to the girls. It is suggested to use norm values from more recently conducted studies and which are representative of the studied population. Growth curves can be used to predict the approximate mandibular dimensions at a particular age

İndirekt yapıştırma tekniğinde kullanılan yapıştırıcıların bağlanma dayanıklılıklarının in vitro ve in vivo karşılaştırılması

Bu çalışmanın amacı, indirekt yapıştırma tekniği için üretilen kimyasal yolla polimerize olan rezin ve ışıkla polimerize olan akışkan rezin kullanılarak yapıştırılan braketlerin bağlanma dayanımlarını in vivo ve in vitro olarak karşılaştırmaktır. Çalışmanın in vitro kısmında, 75 adet premolar diş, üç gruba ayrılmıştır. Bu dişlerin 25 adedi kontrol grubu olmuş ve I.grubu oluşturmuştur. Bu dişlere braketler, ışıkla polimerize olan rezin (Transbond XT, 3M, Unitek) ile direkt yöntemle yapıştırılmıştır. Dişlerin kalan 50 adedi, indirekt bondingi taklit edecek şekilde 5 adet typodont modele fikse edilmiştir. Bu modellerden alçı çalışma modelleri hazırlanmıştır. Çalışma modellerine braketler, ışıkla polimerize olan rezin (Transbond XT, 3M, Unitek) ile yapıştırılmıştır. Sol kadrandaki dişler II. grubu oluşturmuş ve braketler kimyasal yolla polymerize olan indirekt yapıştırma adezivi (Transbond IDB 3M,Unitek) ile yapıştırılmıştır. Sağ kadrandaki dişler ise III. grubu oluşturmuş ve ışıkla polimerize olanakışkan indirekt yapıştırma adezivi (Transbond Supreme LV, 3M, Unitek) ile braketler yapıştırılmıştır. Tüm örnekler, universal test cihazında bağlanma dayanımları yönünden değerlendirilmiştir. Daha sonra tüm örneklerin ARI skorlaması ile artık kompozit miktarları karşılaştırılmıştır. Çalışmanın in vivo kısmına 20 hasta dahil edilmiştir. Hastalardan elde edilen ölçüler üzerine braketler, ışıkla polimerize olan rezin (Transbond XT, 3M,Unitek) ile yapıştırılmıştır. Hastalarda splint-mouth çalışma dizaynı kullanılarak braketleme yapılmış, sağ üst ve sol alt kadranda braketler kimyasal yolla polimerize olan indirekt yapıştırma adezivi (Transbond IDB 3M,Unitek), sol üst ve sağ alt kadranda ise ışıkla polimerize olan indirekt yapıştırma adezivi (Transbond Supreme LV, 3M, Unitek) ile yapıştırılmıştır. Her hastada kadranlar saat yönünde döndürülmüş ve randomizasyon sağlanmıştır. Hastaların braket kopma oranları 12 ay süreyle takip edilmiştir. Elde edilen veriler, tek yönlü varyans analizi, Tukey testi ve Weibull analizi ile değerlendirilmiştir. Ortalama bağlanma dayanımı değerleri, Grup I için 17.6± 6.6 MPa, Grup II için 13.1±4.7MPa ve Grup III için 15.1±5.9 MPa olarak bulunmuştur. Grup I’in değerleri Grup II’den anlamlı derecede yüksek bulunmuştur (P=0.019, P0.05). İn vivo çalışmanın sonuçları değerlendirildiğinde ise braket kopması yönünden gruplar arasında istatistiksel olarak anlamlı bir fark bulunmamıştır (P>0.05). Sonuç: Kimyasal yolla polimerize olan indirekt yapıştırma adezivi (Transbond IDB 3M,Unitek) ve ışıkla polimerize olan indirekt yapıştırma adezivi (Transbond Supreme LV, 3M, Unitek) in vitro şartlarda yeterli bağlanma değerlerine ve in vivo olarak yeterli klinik performansa sahiptir. The aim of this study is to evaluate the shear bond strengths of the chemically-cured and light-cured indirect bonding resins by in vitro and in vivo. For the in vitro study, 75 extracted premolars were divided into three groups. First group was the control group of the study and these were bonded with direct bonding with the light-cured resin (Transbond XT, 3M, Unitek). In the indirect group II and group III, teeth were fixed to the typodonts to imitate indirect bonding, the brackets bonded to the study models with light-cured resin (Transbond XT, 3M, Unitek). In indirect group II, clinical rezin was chemically-cured resin (Transbond IDB, 3M, Unitek) resin and in indirect group III, the clinical resin was light-cured flowable resin (Transbond Supreme LV, 3M, Unitek). The shear bond strenghts and the ARI scores were evaluated; the comparisons between the groups were made. For the in vivo study, twenty patients were bonded with a split-mouth approach: Left half of the upper arch and right half of the lower arch were bonded with chemically-cure resin (Transbond IDB, 3M, Unitek) and right half of the upper arch and left half of the lower arch were bonded with light-cured flowable resin (Transbond Supreme LV, 3M, Unitek). The laboratory resin was light-cured resin (Transbond XT 3M, Unitek) for all of the patients. These quadrants were rotated clockwise with each patient for the randomization. The number and the date of the bracket failure recorded for twelve months. The data obtained from the study were evaluated statistically by analysis of variance, Tukey tests and Weibull Survival analysis. Mean SBS values (MPa) were 17.6± 6.6, 13.1±4.7 and 15.1±5.9 for the control direct group I and for the indirect groups II and III, respectively. There were no significant difference between indirect group III and direct group (P>0,05); whereas there were significant difference between indirect group II and direct group (P=0.019, P<0.05). In vivo evaluation, no statistically significant differences were found in total bond failure rate between the groups (P>0,05). Conclusion: Chemically-cured indirect bonding resin (Transbond IDB, 3M, Unitek) and light-cured flowable resin (Transbond Supreme LV, 3M, Unitek) have sufficient bond strengths in vitro and adequate clinical performance in vivo