(1) Background: Orthodontic appliances have changed and improved with the increasing demand for orthodontic treatment of the general population. Patients desire for shorter orthodontic treatments and for the wearing of more aesthetic devices has led to the technological development of orthodontic brackets; these were manufactured from aesthetic materials (ceramics, composite polymers) and presented different designs regarding the way archwires are ligated to the bracket. The aim of this study was to determine whether there were any differences between the static frictional forces generated by stainless steel (metallic) and polycrystalline alumina (ceramics) conventional and self-ligating brackets. (2) Methods: Static friction assessment was carried out in vitro with a universal testing machine, HV-500N-S (Schmidt Control Instruments, Hans Schmidt & Co. GmbH), intended for measuring compression and traction forces. (3) Results: The study revealed significant differences in static frictional forces at the bracket-archwire interface between the tested brackets. Stainless steel brackets produced lower static friction forces than polycrystalline alumina and self-ligating brackets generally produced lower static frictional forces than conventional brackets. The reduction of frictional forces was noticeable in the first stages of treatment, when thin, flexible orthodontic archwires (0.016” NiTi) are used. Engaged with large rectangular stainless steel archwires, (0.019 × 0.025” SS), the frictional forces produced by conventional and self-ligating metal brackets were similar, no significant differences being observed between the two types of metallic design. However, in the case of tested ceramic brackets, the results showed that the self-ligating type allows a reduction in frictional forces even in advanced stages of treatment compared to conventionally ligation. (4) Conclusions: From the perspective of an orthodontic system with low frictional forces, metal brackets are preferable to aesthetic ones, and self-ligating ceramic brackets are preferable to conventional ceramic brackets.
Lichen planus is a chronic autoimmune multi-factorial inflammatory condition of the mucocutaneous skin that mainly interests the skin and oral mucosa. Oral Lichen Planus (OLP) affects 0.5 to 1% of the world's population and all human races equally. The factors that act as triggers of autoimmune processes and determine the appearance of OLP are represented by genetic predisposition, skin injuries, viral infections, contact allergies, and medications. OLP affects the oral mucosa and occurs frequently on the inside of the cheeks and less often on the edges of the tongue, gums, or lips. The condition is manifested by the appearance of painful erosions and mouth ulcers, accompanied by erythema and gingival scaling, and sometimes localized inflammation of the gums, near the amalgam fillings. There are 132 genes currently involved in the etiopathogenesis of OLP, but only a few appear to play a major role. These genes have been termed "leader genes". Thus, based on bioinformatics studies, the main genes involved in the pathogenesis of OPL are JUN, EGFR, FOS, IL2, and ITGB4. Although genetic status, immune system background, and infectious diseases are considered to be the most important incriminating and determining factors, the etiopathogenesis of OLP remains poorly known. Further genetic research is needed in order to achieve the generalizability of the findings and to strengthen the obtaining results.
Congenitally missing teeth, the most common dental anomaly, refers to teeth whose germ did not develop sufficiently to allow the differentiation of the dental tissues. This study aimed to determine the importance of genetic investigations on oral health-related quality of life in children with congenitally missing lateral incisors. We are presenting a genetic study performed by the A.S. Division of Medical Genetics, in Bucharest, Romania, in the case of a patient (16-year-old boy) presenting bilateral maxillary lateral incisor agenesis in the permanent dentition, a hereditary, non-syndromic familial hypodontia in three successive generations, which suggest an autosomal dominant inheritance, combined with aplasia of maxillary third molars. The oral visual examination and the radiological exam of the patient were completed with the oral photographic examination, the family historyinvestigation, the pedigree, and the analysis of the studied family’s genealogical tree, after acquiring the signed informed consent of the patient. The genetic investigations of the congenitally missing lateral incisors, allow the calculation of the anomaly recurrence risk amongst offspring, and the direct and specialized monitoring of affected families, in order to limit the potential complications.
Dento-alveolar disharmony with crowding is a common reason for orthodontic treatment with not fully understood or unequivocally demonstrated causes. This study investigated the correlations between teeth dimensions, arch lengths, and crowding during the mixed dentition period. A cross-sectional study on 100 dental casts of patients with class I malocclusions was performed. Dental arches were classified as non-crowded, moderately crowded, severely crowded, and spaced. The mesio-distal widths, bucco-lingual sizes, and crown proportions of permanent teeth were assessed. The results indicated that arch length measurements showed smaller values in crowded arches. The mesio-distal dimensions of upper central incisors and lower lateral incisors were larger in patients with crowding. The bucco-lingual dimensions of upper incisors were decreased, the bucco-lingual dimensions of lower central incisors and permanent first molars were increased in crowded arches. Upper incisors and lower lateral incisors presented larger crown proportions in crowding cases. Low negative correlations were found between mesio-distal diameters of maxillary central incisors, lower lateral incisors, lower permanent first molars, and the values of arch space discrepancies. In conclusion, crowding in the mixed dentition could be associated with reduced arch lengths, increase in mesio-distal sizes of incisors and lower permanent first molars, and variations of bucco-lingual dimensions and crown proportions of incisors and lower permanent first molars.
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