No abstract

Introduction: Tooth impaction is defined as the absence of a tooth on the arch, after its normal eruption age. The main reason canines are impacted is the lack of space required for the tooth to erupt.Aim of study: The main objective of this study is to determine the types of malocclusions associated with canine impaction (Lindauer classification). A secondary objective is to establish the correlation between these parameters and identification of subjects with high risk of canine impaction based on pre-existing malocclusion.Material and methods: This study was performed on a sample of 20 patients, 9 men and 11 women. The dental casts were subject to Angle classification and various measurements such as arch perimeter, Pont’s index, sum of the mesiodistal width of the incisor and arch length were performed. The Lindauer sectorial classification was determined based on the patients’ panoramic radiography.Results: According to the data collected, the Class II /2 malocclusion is more frequent, and it is associated with the impacted canine (approximately 50%). According to the Lindauer classification higher frequency of the impacted canines was found in Sector IV.Conclusion: The diagnosis for impacted canines is often associated with Class II /2 malocclusion, and according to the Sector classification, it is often localised in Sector IV.

Introduction: The fundamental mechanical properties of 3D printed surgical guides used in orthodontics represent an important indicator for the accuracy of the insertion of skeletal anchorage devices. The tensile strength of devices printed by stereolithography (SLA) and digital light processing (DLP) methods, respectively, is influenced by factors such as finishing process. Aim of the study: This study illustrates a comparison of the tensile strength in two different types of 3D printed devices (SLA, DLP respectively) undergoing or not a standard process of polishing. Material and methods: Twenty-four specimens obtained according to ASTM D638-14 (Standard Test Method for Tensile Properties of Plastics) were used for the evaluation of tensile strength. Four groups of 6 samples from each category were created: SLA polished, SLA unpolished, DLP polished and DLP unpolished. After removing the support, finishing was performed to obtain smooth surfaces, according to the manufacturer’s recommendation. Type V specimen was used to perform tensile tests in accordance with the standard procedures ASTM D638-14 which recommends at least five specimens to be tested for each sample. One-way analysis of variance (ANOVA) and t-test showed statistically significant results at p < 0.05. SPSSv17 software was used for statistical analysis of the numerical variables, and also descriptive statistics were performed. Results: The measurements included: tensile strength (maximum load), tensile stress at maximum load and tensile strain at maximum load. The maximum load (tensile strength) of the polished specimens was lower, both for the SLA and DLP, with no statistical significance results. Conclusions: The conclusions indicated differences between maximum load and tensile stress at maximum load between polished and unpolished specimens, in both SLA and DLP groups. Althought the polishing process reduces the tensile strenght, the data analysis did not present statistically significant results.

Introduction. It is well known that previously has been demonstrated a correlation between respiratory function and the harmonious craniofacial development and head posture respectively. Aim of the study. The purpose of this study was to investigate the correlation between rapid maxillary expansion (RME) and the change in natural head position (NHP) resulting from the consequent change in airway resistance and to elucidate how RME influences NHP in terms of cephalometric angles in children with nasal obstruction. Material and methods. The study included 12 girls and 8 boys who had a history of mouth breathing, as confirmed by the parents and ORL specialist and due to this fact, they underwent RME as part of orthodontic treatment. Dental casts, clinical photographs and lateral skull radiographs exposed in natural head position were obtained at the first visit (T1) and 8-10 months (T2) later for all subjects. In order to evaluate the patient’s lateral skull radiographs, I used AudaxCeph software, within which I created a new type of analysis. Student T test and Pearson correlation test were used to statistically analyze the results. Results. Our findings demonstrate that no significant changes in any of the variables are observed in patients treated with rapid maxillary expansion, however a positive correlation was observed in the variables measured before and after the treatment, respectively between the anomaly and the measured values. Positivity can also be detected when examining the correlation between the patient’s gender and the measured values. Conclusions. Based on the obtained results, we cannot state that there is a correlation between rapid maxillary expansion and cervical posture.

The insertion of the fixed retention is an important stage of the orthodontic treatment after fixed appliances. The fixed retainers used in orthodontic treatments must be passive towards teeth, without developing any stress. This characteristic is challenging to achieve due to the mechanical properties (bending properties, stiffness) of the materials the retainers are manufactured from. Residual stress might be generated because of their flexibility and because the chemical composition of the stainless steel wires.This study aims to determine the mechanical properties of different austenitic stainlees steel wires used in retention. Also, we have compared the mechanical properties of wires with different sizes, as well as wires with the same size, new and intra-orally used. The results confirm that the mechanical parameters of the two types of wires used in fixed retention (3 braided round wires and 6 braided Flat wires) present statistically insignificant differences. The study also reflects that the mechanical properties of the intra-orally used wires showed decreased values of the parameters.