ABSTRACT
Background and aims: The early detection of dental crowding and its potential for aggravation is important during the clinical examination of mixed dentition patients, and these desiderates can be addressed by including among the clinically assessed items a series of accessible morphological characteristics of teeth and dental arches. The present study investigates possible correlations between morphological features of permanent teeth, widths of dental arches, and the onset of dental crowding during mixed dentition. Methods: A selected group of 100 class I dental casts on mixed dentition was analyzed. The dental arches were grouped as spaced, normally aligned, and crowded. The dental parameters consisted of mesiodistal dimensions of permanent teeth and specific morphological features of permanent incisors and first molars. The anterior and posterior arch widths according to Pont indices were measured. Results: Statistical analysis of data showed that mesiodistal dimensions of the permanent upper central incisors and lower incisors are significantly larger on severely crowded arches than on normally aligned arches; increased differences between mesiodistal dimensions of central and lateral permanent upper incisors and the presence of semi-shavel incisors and Carabelli cusps are associated with a greater extent of anterior crowding. The severely crowded arches presented significantly narrower anterior and posterior arch widths. Conclusions: Increased mesiodistal dimensions of permanent incisors, the presence of incisors shoveling, the Carabelli cusps on upper first permanent molars, and narrowing of dental arches during the early mixed dentition period were associated with severe dental crowding in class I cases.
ABSTRACT
(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.
ABSTRACT
The phenotypic variety of Angle Class III malocclusion requires in-depth investigation of the skeletal changes from a diagnostic, prognostic and therapeutic perspective alike. The aim of our study was to evaluate the particularities of vertical cephalometric parameters of patients with Class III malocclusions, according to gender and age group. Eight parameters were analyzed on lateral cephalograms of patients with Class III malocclusions and, comparatively, on lateral cephalograms of a group with Class I malocclusions. The results, grouped by gender and age, suggest that values of the gonial angle, values of the angles formed between the mandibular plane and the anterior cranial base, respectively the Frankfurt Horizontal plane were higher for patients with Class III malocclusions, differences being statistically significant especially after the pubertal growth period. Class III patients had lower values for the upper gonial angle and higher ones for the lower gonial angle. Furthermore, for patients with Class III malocclusions the Jaraback ratio decreased, based on the significantly higher values of the anterior facial height. No sexual dimorphism was associated with variation of the investigated parameters.
