Aim: The aim was to assess the changes in the mandible in patients treated with conventional brackets compared to those treated with self-ligating brackets. In particular, we focused on the degree of transversal changes and the length of therapy. Material and method: The sample included 43 patients; 11 men and 32 women. The mean age was 22.2 years. The patients had complete permanent dentition, were treated without extractions, molars in Angle Class I. The subjects were divided into two groups – conventional brackets, self-ligating brackets. Measurements were performed in scans of cast models made prior to therapy (T1), after removal of fixed appliance (T2), the length of treatment was given in months. The changes in intercanine and intermolar distance were compared in teeth and in relevant points on WALA ridge of the mandible. ORTODONCIE | ročník 33 | č. 2/2024 ODBORNÉ PRÁCE / ORGINAL ARTICLES 29 www.ortodonciejournal.cz | e-mail: redakce@ortodonciejournal.cz, office@ortodonciejournal.cz Results: In lower first molars the change in intermolar width was significant in both groups both at T1 and T2. The change was significantly bigger in the group with self-ligating brackets. The change in intercanine width between T2 and T1 was statistically significant only in the group with self-ligating brackets when measured on canine tips. Measurements at FA points (the most prominent point in the middle of longitudinal axis of the clinical crown) did not prove significant change. At WALA the change between T2 and T1 was significant only in the group with self-ligating brackets and only in first lower molars (clinically the change was small). The change in the distance WALA-FA in first lower molars on the left and on the right between T2 and T1 was statistically significant in both groups, however, it was significantly bigger in the group with self-ligating brackets. The difference in the length of therapy was not statistically significant. Conclusion: In patients with self-ligating brackets there is a greater expansion in first molars and canines. We can also observe more prominent vestibular inclination of canines and first molars. In patien

Aim: The aim was to confirm the correlation between chronological age, skeletal age according to X-ray picture of the hand and wrist, and the stages of teeth development, and to determine whether the assessment of teeth development can be used to establish the stage of growth of an individual. Material and method: 362 adolescents were included in the study; 180 boys between the age 11.5–15.5, 182 girls between the age 10.5–14.5. To assess teeth in OPG Demirjian’s classification was used. We assessed teeth 43, 44, 45 and 47 in the mandible, and 13, 14, 15, 17 and 18 in the maxilla. To assess radiographs of the hand and wrist Björk, Grave and Brown classification was applied. Results: The correlation of skeletal and dental age was proved. The highest correlation was found in lower permanent canine, both in girls and boys. S-stage in radiograph of the hand (the stage prior to the maximum growth spurt) corresponds to the stage of the lower canine root with parallel walls (G-stage according to Demirjian). Thus, in case OPG of lower permanent canine shows parallel walls of the root canal the maximum of growth spurt occurs within 0.5–1 year. The maximum growth spurt (MP3cap stage) and the following stages correspond to the situation when lower canine apex is closed (H-stage according to Demirjian). This can help us in the correct timing of orthodontic treatment. ORTODONCIE | ročník 33 | č. 2/2024 ODBORNÉ PRÁCE / ORGINAL ARTICLES Recenzovaný časopis České ortodontické společnosti 14 Conclusion: The assessment of the developmental stages of teeth, namely lower permanent canine, is used in the planning of orthodontic treatment, and can serve as

Aim: The aim is to assess stability of overjet, overbite, and upper intermolar width after the orthodontic-surgical correction of orthodontic anomaly with segmental H-osteotomy of the maxilla. Material and method: The retrospective study works with 40 patients who underwent the segmental osteotomy of the maxilla. Each patient had aɸcomplete orthodontic documentation before the therapy (T1), prior to the surgery (T2), after aɸcompletion of an orthodontic treatment (T3) and approx. 25 months after aɸremoval of fixed appliance, minimum of 1 year after the completed orthodontic treatment and at least 1.5 years after the orthognathic surgery (T4). In every time interval, aɸdigital model of aɸdentition was made to measure the overjet, the overbite and the upper intermolar width. Results: During aɸ long-term check-up the value of the overjet showed aɸ clinically and statistically insignificant decrease by 0.1 ± 0.5 mm. The overbite also showed aɸclinically insignificant decrease by 0.1 ±0.5 mm; in none of the cases there was aɸclinically significant bite opening. The average value of the upper intermolar width was 38.9 ±3.1 mm before the beginning of therapy, prior to orthognathic surgery the value increased due to orthodontic treatment by 0.5 ±1.7 mm. After the active therapy completion, the value increased by 0.9 ±1.7 mm, i.e. by 1.4 ± 2.6 mm compared to the initial condition. In aɸlong-term check up, the average loss of uper intermolar width by 0.4 ±0.7 mm was recorded.

Aim: The work assesses force characteristics of one type and size of elastics, specifically 3/16“ medium elastics, of five different manufacturers. We compared initial forces, and particularly the relationship between their force degradation over aɸperiod of time. Material and method: 500 latex elastics 3/16“ medium from Dentaurum, American Orthodontics, 3M, Ortho Organizers and G & H Orthodontics (100 of each) were tested. Force was measured with dynamometer at time 0, 2, 8, 24 and 48 hours. Elastics were stretched to triple of their original diameter and they were placed onto the plate manufactured by us. The plate was produced with 3D printer. Then everything was put into an incubator at the temperature of 37 °C and constant humidity. Shapiro-Wilk normality tests, ANOVA and Bonferroni’sɸpost-hoc tests were used for statistical evaluation. Individual manufacturers were asked whether they know in which plants exactly the elastic tractions are produced. Unfortunately, they did not answer the question. Results: The average initial force was between 1.109 N and 1.550 N; elastics made by Dentaurum were closest to the declared force of 1.255 N. The force decreased most during the first two hours. Between the individual producers the decrease of elastic tractions during 24 hours oscillated between 20 and 33%. The greatest drop in force was recorded for American Orthodontics products. The smallest decrease was recorded between 2nd and 8th hour for 3M, and between 24th and 48th hour for OrthoOrganizers products. Conclusion: Intermaxillary elastics of 3/16“ medium measured in vitro differ both in the amount of their initial force and in force degradation. Orthodontists should know the basic parameters of elastic tractions. To secure maximum care aɸdoctor should measure initial force of elastic tractions with dynamometer intraorally.

Aim: The aim is to determine the impact of unerupted canine position on the position of adjacent teeth as well as the relationship of the severity of canine impaction and position, and associated factors of the impaction. Material and method: From CBCTs of the patients treated between 2015 and 2020 at the Department of Orthodontics of St.Anne’s University Hospital 39 scans with unilateral impacted upper canine were selected. There were 25 palatally impacted canines, 14 vestibularly impacted canines. The parameters measurements were carried out with Invivo6 software after setting of the reference planes. Results: Factors associated with canines impaction were proved, such as shift of the midline towards the affected side (by 0.56–0.68 mm), higher incidence of peg shaped lateral incisor (I2) in palatally impacted canines, narrower palate on the side of impacted canine (by 1 mm in palatally and 2 mm in vestibularly impacted canine). In vestibularly impacted canines lateral incisors (I2) were significantly more distally inclined (by 10.3°), in palatally impacted canines lateral incisors (I2) were distorotated by 14.1°and retruded by 7.2°. In vestibularly impacted canines the roots of I2 were shortened by almost 2 mm, in palatally impacted canines by 1 mm. On the side of impacted canines we found higher incidence of bent roots (51.3%) and hooks (12.8%); I2 bent roots were more frequent on the side of palatally impacted canines (32%). Conclusion: The study findings could help in early diagnostics – either clinical or radiological – of impacted upper permanent canines, and in adopting the best strategy of treatment. Disturbed development of impacted canines (shorter length, bent root) calls for early detection and timely orthodontic treatment of the impaction.

The presented article presents a comprehensive survey of current knowledge on impacted maxillary canines with focus on palatal impaction. We worked with the relevant databases and eventually selected the 94 most important studies and monographies. In case of vestibular impaction the literature more or less agrees on that the main cause is the lack of space in the dental arch. However, in case of palatal impaction the situation is not so clear. In etiology of palatal impaction there prevail two opinions: genetic theory and guidance theory. Genetic theory sees genetics as the only cause, while guidance theory says impacted canine is the result of deviations in the shape of upper lateral incisor – agenesis, microdontia, peg shaped crown. Thus, lateral incisor cannot take on the role of guiding crest along which canine erupts into the oral cavity. Other potential causes include local obstruction, pathologies, traumas. However, they appear in only a minimum of cases.

Aim: The study deals with differences in the size of anatomical crowns of first and second maxillary pemolars, and discusses the correlation between the crowns size and sex and skeletal classes of patients. Material and method: The non-randomized retrospective study worked with 152 plaster models of the maxilla. The models were scan­ned, and in these virtual models mesiodistal and buccolingual parameters of teeth anatomical crowns were measured. The models were divided into groups according to patients’ sex and skeletal class according to WITS. Results: Mesiodistal width was significantly bigger in first premolar (mean= 6.68 mm) than in the second one (mean = 6.43 mm). On the contrary, buccolingual dimension was statistically bigger in second premolars (mean value = 9.67 mm) that in the first one (mean value = 9.48 mm). Mean size of teeth was bigger in all parameters in males than females, i.e. mesiodistal dimension in first premolars (males = 6.75 mm; females = 6.61 mm) and in second premolars (males = 6.49 mm; females = 6.38 mm. The same holds true for buccolingual dimension in first premolars (males = 9,65 mm; females = 9.34 mm) and second premolars (males = 9,83 mm; females = 9.50 mm). In males with Class II the mesiodistal width of both first and second premolars is significantly smaller (mean value = 6.54 and 6.31 mm) than in males with Class I (mean value = 6.86 and 6.58 m) and with Class III (mean value = 6.85 and 6.56 mm). Conclusion: First upper premolar is bigger mesiodistally and smaller buccolingually than second upper premolar. Males’ teeth are bigger than females’. Men with Class II have statistically smaller mesiodistal width of first and second premolars than men with Class I and III.

Permanent tooth ankylosis is a multifactorial condition. Its origin on the molecular level is still rather unclear, and due to difficult diagnosis, the prevalence in the population is not known. Ankylosis may be classified into idiopathic (early), where the cause is not definitely known, and secondary (late) resulting either from trauma or inflammation around the tooth root. In general, the diagnosis is based on the patient’s history and clinical picture characterized by the loss of the ankylosed tooth mobility accompanied by a distinct sound on percussion. Radiologically, computed tomography (CT) can be used; it is, however, often substituted by Cone Beam Computed Tomography (CBCT) in order to avoid high radiation load. Extraction of the ankylosed tooth is the most common solution. Other methods include tooth subluxation (potentially with corticotomy) or alveolar distraction with orthodontic treatment. Though more and more advanced imaging methods are used, the early detection of tooth ankylosis is still a challenge and must be considered by dentists and orthodontists when planning therapy.