Orthodontics and Temporomandibular Disorders. Are They Related?

The aim of this review was to evaluate associations between different orthodontic treatment techniques, the role of malocclusion types, and signs and symptoms of temporomandibular disorders (TMDs). Associations between different orthodontic treatment techniques and TMD were found in some studies, whereas most of the reviewed articles failed to identify significant associations. Based on the presently available research, because it has not been demonstrated that malocclusions cause TMDs, it is incorrect to claim that orthodontic approaches can treat or prevent TMDs. Moreover, there is no evidence that any orthodontic treatment causes TMD signs or symptoms. Longitudinal studies are still needed

Postoperative Positional and Dimensional Changes of Mandibular Canal after Bilateral Sagittal Split Set-Back Osteotomy

Objective:This preliminary study was planned to provide information about preoperative mandibular canal (MC) position and the postoperative positional changes of MC and length in three dimensions, with the purpose of providing some assistance in reducing inferior alveolar neurosensory disturbance (IAND).Methods:MC was examined on CBCT data using SimPlant Pro Standalone 13.0. MC locations were measured in all dimensions, with respect to mandibular bony borders.Results:The results showed that MC is frequently located in the midthird of the ramus anteroposteriorly and superoinferiorly and in the midthird of the corpus superoinferiorly. Postoperatively, ramus width was increased, ramus length was decreased significantly, and MC was repositioned laterally and inferiorly. MC length was decreased on both sides, non-correlated with the set-back amounts.Conclusion:Preoperative results may be beneficial for the prediction of MC position for surgeons, and postoperative results will be used for the following studies to correlate postoperative positional changes with IAND

Cephalometric Variability Among Siblings: A Pilot Study

Objective:To determine whether multiple siblings resemble one another in their craniofacial characteristics as measured on cephalometric radiographs.Methods:This study was conducted retrospectively using the Forsyth Moorrees twin sample. A total of 32 families were included, each with ≥4 postpubertal siblings, totaling 142 subjects. Only 1 monozygotic twin was included per family. Headfilms were digitized, skeletal landmarks were located, and 6 parameters that indicated sagittal jaw relationships and vertical status were measured. Diverse statistical approaches were used. Dixon’s Q-test detected outliers in a family for a given parameter. Manhattan Distance quantified similarity among siblings per parameter. Scatter plots visually displayed subject’s measure relative to the mean and standard deviation of each parameter to assess the clinical relevance of the differences.Results:A total of 11 families (34.4%) had no outliers on any parameter, 13 families (40.6%) had outliers on 1 parameter, and 8 families (25%) had outliers on ≥2 parameters. We identified 29 individuals with at least 1 outlying measure (20.4%). Among these, only 2 individuals (1.4%) were significantly different from their siblings for more than 1 measurement. Although the majority of the families did not demonstrate any statistical outlier, the ranges of the measurements were clinically relevant as they might suggest different treatment. For example, the mean range of SNB (Sella-Nasion-B point) angles was 7.23°, and the mean range of MPA was 9.42°.Conclusion:Although families are generally not dissimilar in their craniofacial characteristics, measurements from siblings cannot be used to predict the measurements of another sibling in a clinically meaningful way

Heritability of facial soft tissue growth in mono- and dizygotic twins at 12 and 17 years of age: A retrospective cohort study

OBJECTIVE The purpose of this investigation of untreated monozygotic and dizygotic twins was to identify the genetic and environmental components to the facial soft tissue growth. SETTINGS AND SAMPLE POPULATION The sample consisted of 52 untreated monozygotic twins (36 male and 16 female) and 46 untreated dizygotic twins (23 male and 23 female) from the Forsyth Moorrees Twin Study (1959-1975). MATERIALS AND METHODS Lateral cephalograms were taken at 12 and 17 years of age and traced to analyse facial convexity, nasolabial angle, upper and lower lip thickness, upper and lower lip profile and nose prominence. The genetic and environmental components of variance were analysed with structural equation modelling for multilevel mixed-effects model. RESULTS At 12 years of age, strong additive genetic influence was seen for facial convexity (70%), upper lip profile (66%) and nose prominence (65%), whereas strong dominant genetic components were found for upper lip thickness (56%). Nevertheless, under unique environment influence were nasolabial angle (58%), lower lip profile (51%) and lower lip thickness (64%). At 17 years of age, only upper lip thickness (55%) and nose prominence (84%) were under strong additive genetic control, while the rest of the variables were under strong dominant genetic control. The only exception was lower lip thickness (61%), which is still influenced by the unique environment. CONCLUSION Although monozygotic/dizygotic twins share at least part of their genome, at both times either additive, dominant or environmental components were found. Nevertheless, at 17 years of age most of the variables are either under additive or dominant genetic influence

Does the Bone Cement Affect Miniscrew Stability?

Objective:The purpose of this study was to determine whether bone cement increased the resistance of miniscrews against pull-out and shear forces.Materials and Method:Sixty commercially available miniscrews were placed into bovine bone samples (one each) at a 90° angle, using a custom-made orientation jig and controlling torque (30 N-cm) and rotation (20 rpm) with a rechargeable screwdriver. The miniscrews were inserted using three different methods: self-drilling, predrilling, and predrilling with bone cement application. Pull-out strengths and shear tests were performed using a universal testing machine.Results:Nonparametric Kruskal-Wallis tests were used for comparisons between groups, and Bonferroni-adjusted Mann-Whitney U tests were used to detect different group(s) (α/3=0.016). There was a statistically significant difference between the pull-out strengths of the groups (p<0.01). The self-drilling group had a significantly lower pull-out strength at failure than the other groups (p<0.016). The pullout strengths of the miniscrews placed with bone cement had a significantly higher pull-out strength than the predrilling group. In shear tests, there was no statistically significant difference among the groups.Conclusion:This study is the first report demonstrating the effects of bone cement on stability and resistance to failure at the bone-miniscrew interface. These results show that the use of miniscrews with bone cement is a promising method that may extend the limits of force application

Hızlı üst çene genişletmesini takiben ve bir yıllık retansiyon dönemi sonrası maksiller sinüslerde meydana gelen değişikliklerin 3 boyutlu olarak incelenmesi

HIZLI ÜST ÇENE GENİŞLETMESİNİ TAKİBEN VE BİR YILLIK RETANSİYON DÖNEMİ SONRASI MAKSİLLER SİNÜSLERDE MEYDANA GELEN DEĞİŞİKLİKLERİN 3 BOYUTLU OLARAK İNCELENMESİ Çalışmanın amacı hızlı üst çene genişletmesi öncesi, 3 aylık pekiştirme sonrası ve 1 yıl sonrası ölçülen maksiller sinüs hacimlerinin bilgisayarlı tomografi verileri üzerinde değerlendirilmesidir. Bu çalışmaya cap-splint Hyrax aygıtı ile hızlı üst çene genişletmesine ihtiyacı olan 11’i kız 10’u erkek toplam 21 bireyden alınan veriler dahil edilmiştir. Hacimsel ölçümler 3boyutlu tomografik model oluşturma programı (Mimics v.14.0, Materialise, Belçika) kullanılarak gerçekleştirilmiştir. Bu programda her tomografik kesitte maksiller sinüslerin görüntüsü diğer komşu dokulardan ayrılmış ve 3 boyutlu olarak modellenmiştir. Ardından elde edilen dijital modellerin hacim bilgileri değerlendirilmiştir. Hızlı üst çene genişletmesinin 3 döneminde elde edilen veriler karşılaştırıldığında istatistiksel olarak anlamlı bir artış görülmüştür (P <0.001). 3 Dimensional Evaluation of Maxillary Sinuses After Rapid Maxillary Expansion and Following One Year Retention Period Melih Motro The purpose of this study was to evaluate volumetric differences of the maxillary sinus on computed tomography data taken before RME, after 3 months of retention and 1 year following retention. Twenty one consequtive patients (11 girls, 10 boys ) who required RME with cap splint Hyrax appliances as part of their orthodontic treatment were studied. Volumetric measurements before (T1), after retention period (T2) and one year following the retention period (T3) of RME were performed using a 3D tomography prototyping software (Mimics v.14.0, Materialise, Belgium). Maxillary sinus regions were isolated in every slice and then the 3d images were constituted. Sinus volumes were measured. The acquired data were compared for three periods by using repeated measures ANOVA and post-hoc comparisons were made by paired samples t-test. In the volumetric evaluation of maxillary sinuses in RME patients, sinus volume increase was statistically significant in all three times (P <0.001)

Open-bite treatment of a case by means of zygomatic plate anchorage

Treatment of anterior open bite cases is usually a challenging issue and the treatment results are often hard to maintain. Many treatment modalities were presented throughout the years in the literature where in most, malocclusion is corrected primarily by extrusion of the incisors or preventing passive eruption of posterior teeth. Surgical correction is another main approach in treatment of skeletal openbite cases. However, patients may hesitate to have surgery due to the risks, complexity and costs of this treatment. In this case report a minimally invasive method is shown in which posterior teeth are intruded by using zygomatic anchorage. For this purpose multi purpose implants were placed on the zygomatic buttress area to act as anchorage units. The intrusive force application was started by attaching two 9mm NiTi coil springs bilaterally to the bended “I” shaped processes that access to the oral cavity through the mucosa. Posterior dentoalveolar intrusion was achieved in 6 months and the intrusion was maintained with wire ligation between the implant and the molar tubes throughout the treatment. Lower face height to total face height ratio decreased by 1%. 1mm overbite was achieved. Normal smile line concomitant with the lower lip contour and esthetic gingival exposure was also achieved. If intrusion of the posterior teeth is necessary skeletal anchorage through zygomatic multipurpose implants can be used as a good treatment alternative to orthognathic surgery

3 dimensional evaluation of maxillary sinuses after rapid maxillary expansion and following one year retention period

The purpose of this study was to evaluate volumetric differences of the maxillary sinus on computed tomography data taken before RME, after 3 months of retention and 1 year following retention. Twenty one consequtive patients (11 girls, 10 boys ) who required RME with cap splint Hyrax appliances as part of their orthodontic treatment were studied. Volumetric measurements before (T1), after retention period (T2) and one year following the retention period (T3) of RME were performed using a 3D tomography prototyping software (Mimics v.14.0, Materialise, Belgium). Maxillary sinus regions were isolated in every slice and then the 3D images were constituted. Sinus volumes were measured. The acquired data were compared for three periods by using repeated measures ANOVA and post-hoc comparisons were made by paired samples t-test. In the volumetric evaluation of maxillary sinuses in RME patients, sinus volume increase was statistically significant in all three times (P<0.001)