RESUMEN
Malocclusions have a continuously increasing prevalence from one generation to another as a result of climate change, soil, atmosphere, and water pollution. All of these aspects have unfavorable consequences for the nutritional scheme. Thus, nutrition, together with other etiopathogenic factors, contributes to complex alterations in the somatic development of the entire organism and, implicitly, of the cephalic extremity. The study group included 4147 children from randomly selected schools from Vâlcea County, Romania. The aim of this study is to determine the prevalence of malocclusions in schoolchildren in Vâlcea County, Romania, according to the three main classes of malocclusions (according to Angle's classification), age groups (from 6 to 10 years old and from 11 to 14 years old), gender (male and female), and place of origin (rural and urban). For Angle class I malocclusions, we recorded the highest prevalence (48.78% of the total number of schoolchildren with malocclusions), followed by Angle class II malocclusions (45.85% of the total number of schoolchildren with malocclusions), and for Angle class III malocclusions we found the lowest prevalence (5.37% of the total number of schoolchildren with malocclusions). According to gender, we found the highest prevalence in the female gender (29.90% of the total number of female subjects), while in the male gender, we recorded a prevalence of 27.70% of the total number of male subjects. Regarding the place of origin, there is a higher prevalence of malocclusions in urban areas (29.16%). The study subgroup included 140 children randomly selected from the total number of subjects in the study group. They were included in a more advanced study. The aim is to find potential associations between the presence of malocclusions and various oral variables. Categorical variables were expressed as numerical values and percentages, and their association was evaluated with either the Chi-square test of association or homogeneity, or the Fisher Exact test. The acquired data were incorporated into a binomial logistic regression model to assess the likelihood of developing malocclusions in relation to the following variables: defective phonation, bruxism, frequency of teeth brushing, onychophagia, oral respiration, infantile deglutition, placing objects between the maxillaries, thumb sucking, and salivary aspects. It is also aimed at comparing the results obtained with similar ones from the specialized literature.
RESUMEN
This study aimed to assess the in vitro biocompatibility of titanium (Ti) alloy orthodontic mini-implants by correlating human osteoblasts (HOb) response with chemical composition and surface morphology of mini-implants. HOb were cultivated with or without custom-made and commercial mini-implants, discs and filings. The surface morphology and chemical composition of the implants were assessed under the scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) microanalysis system. Cell viability, adhesion and proliferation were analyzed by optical microscopy and flow cytometry. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) reduction and lactate dehydrogenase (LDH) release tests were used to assess the cytotoxicity of discs and filings-treated culture medium. Shape, adhesion, and multiplication of HOb were not significantly altered by the presence of mini-implants, discs or filings in culture, even though Ti alloy may exert in vitro a low cytotoxic effect on HOb adhered to discs. Morphology analysis by SEM demonstrated that custom-made mini-implants' surface differs from that of commercial mini-screws in terms of surface finish and roughness, whilst EDX analysis showed largely similar percentages of Ti, aluminum and vanadium for the two types of implants. No major differences were noticed regarding the effect exerted in vitro on HOb by the investigated implants. The new mini-implants have a convenient in vitro cytotoxicity profile on HOb.
