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Background The transfer of digital radiographic images is widely practiced. Digital image processing can influence the perception of image quality. The question arises as to how exposure, internal image adjusting algorithms and image file transfer affect the optical density of digital radiographs. Objectives To evaluate the influence of exposure time, optimization and file transfer on digital radiographs. Material and methods Calibration patterns were formed and a series of digital radiograms were recorded under standardized conditions. The radiographs were exported and then imported into the same software. Three groups of radiographs were analyzed: A - images originally performed and recorded in the software; B - images imported after exporting an optimized image; and C - images imported after exporting an image without optimization but with measurements of the density of the marked regions of interest. Results An increase of the exposure time decreases optical density. The optimization algorithm increases contrast and decreases differences between exposure times. Long exposures affect the visibility of objects with low optical density. After importing the images in Group B, there was a risk of using the optimization algorithm twice. When optimization was not performed, there were no differences between Groups B and A. In Group C, there was no risk of doubling the optimization algorithm. Conclusions The transfer of digital radiographs can exert an influence on the optical density values. To avoid the risk of image distortion, files should be exported without image optimization.

Background Cleft lip and palate (CLP) is a genetic and environmental malformation of the face. The resulting interruption of the tissue in the mouth and nasal cavity undoubtedly impairs basic physiological functions, which impacts the quality of life (Qol) of such patients. Objectives To assess orofacial dysfunction using the Nordic Orofacial Test-Screening (NOT-S) in a group of Polish children with unilateral CLP (UCLP). The following hypotheses were presented: 1) orofacial dysfunction is more common in children with UCLP and 2) patients with UCLP have a worse QoL than the control group. Material and methods Seventy children at the age of 7-13 years took part in the study. The inclusion criterion was a diagnosis of UCLP. The control group (non-UCLP) was matched by gender and age to the cleft group. The research used the NOT-S questionnaire. Results In the cleft group, there were statistically significantly more disorders of functions, such as breathing, chewing and swallowing, and drooling; in the NOT-S examination, there were more disorders of the face at rest, facial expression and speech in the cleft group. Comparing the NOT-S total scores, it was found that in the cleft group, there a disorder of at least 1 function was statistically significantly more prevalent than in the control group. Likewise, the median results in the cleft group were 3 points higher than in the control group. Conclusions Using the NOT-S survey, it was possible to confirm both hypotheses. Orofacial dysfunction is more common in children with UCLP and this contributes to a worse QoL for them than for children without UCLP.

(1) Background: The aim of this work was to systematically review the literature on the relation between the levels of elements in hair (toxic elements and trace elements) on the occurrence of autism spectrum disorder. (2) Methods: Search strategy and study selection: Original articles were included if they met the including criteria that report the trace element levels in hair. The following databases were screened: Medline (via PubMed), Scopus, Web of Science, Google Scholar (from 2000.01.01 to 2020.11.11). The main search terms used were “hair element analysis and trace elements and autism”. (3) Results: The papers available describe results of studies undertaken with the use of different methodology: diversified size of experimental groups, different sampling and analytical techniques. Therefore direct comparison of the results is not informative. (4) Conclusions: It was found that pathogenesis of autism spectrum disorder was associated with the exposure to toxic elements (e.g. Hg and Pb) which act as neurotoxicants. Also, the relation between some microelements seem to be significant, in particular the ratio Zn/Cu. Higher level of zinc and level levels of copper play the protectory role.

Background Cleft lip and palate (CLP) cause severe malocclusion, which requires numerous orthodontic interventions in specialized centers. There is little literature regarding the overall orthodontic burden of care for these patients. Objectives The aim of the study was the evaluation of orthodontic-care burden for patients treated in the Division of Facial Abnormalities at the Department of Dentofacial Orthopedics and Orthodontics of Wroclaw Medical University in Poland. Material and methods The medical data of patients with complete unilateral and bilateral cleft lip and palate (ULCP and BLCP) who finished orthodontic treatment between 2012 and 2019 was evaluated. The duration of orthodontic treatment, the number of removable appliances, the number of kilometers traveled as well as the number of visits and surgical procedures performed were recorded. The sample was divided into 2 groups according to the World Health Organization (WHO) International Classification of Diseases (ICD-10) diagnosis codes. All data was subjected to statistical analysis. Results For the UCLP patients (n = 54), the mean time of orthodontic treatment was 9.24 years, the mean number of orthodontic appointments was 62.91, the mean number of removable appliances was 4.12, the mean number of surgical procedures was 3.35, and the mean distance traveled to visit the center for orthodontic appointments was 5,466.95 km. For the BCLP patients (n = 19), the mean time of orthodontic treatment was 10.16 years, the mean number of orthodontic appointments was 66.26, the mean number of removable appliances was 4.12, the mean number of surgical procedures was 4.05, and the mean distance traveled to visit the center for orthodontic appointments was 3,758.23 km. Conclusions The orthodontic treatment of patients with UCLP and BCLP is very burdensome for the patients. However, the burden of care in the Division of Facial Abnormalities at the Department of Dentofacial Orthopedics and Orthodontics of Wroclaw Medical University in Poland is not greater than in other European countries.

Introduction. Functional treatment is the type of treatment preferred in young patients with lateral bite because it leads to simultaneous improvement of occlusion and facial profile. Objective. The aim of this study is to assess bone changes within the condylar process of the mandible and to associate them with the changes observed in the analysis of lateral cephalograms and in the patient’s occlusion. Materials and Methods. Cone beam tomography of the temporomandibular joint, lateral radiogram of the skull, was performed at the beginning of treatment and after one year of therapy. Changes in cephalometric radiograms were evaluated by analyzing them and shown by making superimposition and staining layers. For the purpose of assessing bone changes within the condylar process, digital 3D solids of these processes were generated using data from computed tomography. Results. Correction towards Angle’s dental class I, overjet reduction from 8 mm to 3 mm, and improvement of the patient’s profile were obtained. A rotation of the occlusal plane and improvement in an ANB by 1° and in the WITS measurement by 2.7 mm were observed. A growth of the condylar processes “backwards” and “upwards” was also observed, as well as a change of their shape and volume. Conclusions. The obtained results suggest that the patient’s significant improvement in occlusal conditions is due to posterior growth stimulation of the condylar processes of the mandible. The results confirm the validity of using this treatment technique in the case of growing children with complete posterior occlusion.

Saethre-Chotzen syndrome (SCS) belongs to a group of rare congenital disorders connected with craniosynostosis and syndactyly. The purpose of this paper is to provide a review of the literature, to collect all reported symptoms and to describe the case of an 11-year-old female with SCS. The electronic databases PubMed and Scopus were searched to gain all symptoms of SCS described in the literature. The most common features of SCS described in the literature are synostosis of the coronal suture, syndactyly, facial asymmetry, low hairline, prominent ear crus, prominent nasal bridge, eyelid ptosis, and ocular hypertelorism. Less common symptoms include hearing loss, renal abnormalities and cardiac defects. Intraoral manifestations of SCS include maxillary hypoplasia, mandibular prognathism and high arched palate. Moreover, in some patients mental disability is observed, which may be connected with the size of the deletion in the Twist gene. There are no pathognomonic symptoms of SCS, which would indicate a diagnostic problem. Our patient displayed small dysmorphic changes within the skull and limbs and proper intellectual development. On the basis of an intraoral, extraoral examination and X-rays, she was diagnosed with relative mandibular prognathism. Currently, she is treated with a removable appliance. This report emphasizes a considerable variability of symptoms in SCS and highlights the most common features.

Background Information regarding masticatory muscle function in children with cleft lip and palate (CLP) is limited. As a consequence, research on masticatory muscle activity in cleft subjects is needed. Aim To assess masticatory muscle activity in children surgically treated for CLP as well as identify the possible factors associated with this activity. Design The sample comprised 82 children with mixed dentition and Class I occlusions (25 children with unilateral CLP and 57 subjects with no cleft abnormalities). A DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany) was used to take electromyographical (EMG) recordings of the temporal and masseter muscles both in the mandibular rest position and during maximum voluntary contraction (MVC). Results Patients with clefts showed a significant increase in temporal muscle activity at rest compared with the controls. The presence of clefts and unilateral posterior crossbites are factors strongly associated with increased temporal muscle EMG potentials during rest position. Conclusions Children with clefts have altered temporal muscle function. The presence of posterior crossbites affects the temporal muscle activity in cleft subjects. Early diagnosis and orthodontic treatment of malocclusions are necessary to achieve functional improvement in these patients.

An overview of professional literature referring to the release of metal ions from fixed orthodontic appliances and their influence on oral mucosa in conditions of in vivo are presented, along with a detailed analysis of the exposure of the cells of cheek mucosa epithelium to metal ions. Electronic databases (PubMed, Elsevier, Ebsco) were searched with no language restrictions. The relevant orthodontic journals and reference lists were checked for all eligible studies. A total of 38 scientific articles were retrieved in the initial search. However, only 7 articles met the inclusion criteria. Statistically significant differences in the levels of the amount of nickel ions, cobalt ions and chromium ions were observed in cells of cheek mucosa. The most biocompatible material used in the production of fixed orthodontic appliances is titanium, and the least biocompatible material is steel, which releases the largest amount of nickel and chromium. Metal ions are released from fixed orthodontic appliances only in the first phase of treatment. It is recommended to conduct further, long-term research on a larger number of patients to define the influence of using fixed orthodontic appliances and biological effect they might have on tissues.

Objective. Clinical comparison of the survival rates between stainless steel and ceramic brackets over a 12-month period. Materials and Methods. The study involved 20 consecutive patients with diagnosed malocclusion that required two-arch fixed appliance treatment. The participants were randomly divided into two 10-member groups. Group 1 was treated with Abzil Agile (3M Unitek) stainless steel brackets; group 2 was treated with Radiance (American Orthodontics) monocrystalline ceramic brackets. All the brackets were bonded by the same operator. Over the next 12 months, all bracket failures were recorded with each appointment. The received data were processed statistically using the Mantel–Cox test, Kaplan–Meier method, and Cox hazard model. Results. A total of 381 brackets were bonded, 195 of which were metallic brackets and 186 were ceramic ones. In the 12-month observation period, there were 14 metal (7.2%) and 2 ceramic bracket (1.1%) failures. The overall failure rate was 4.2% (n = 16). The majority of failures (14 brackets; 87.5%) occurred during the first 6 months of the experiment, 12 (83%) of which were metal brackets and 2 (100%) were ceramic brackets. The statistical analysis revealed significant differences between the groups (p<0.05). Conclusions. Metal brackets demonstrated significantly higher failure rates than ceramic brackets for both 6- and 12-month observation periods (p<0.05). The 6% difference between the brackets is clinically significant as it corresponds to one additional failure within 12 months.

Down syndrome (DS) is the most often diagnosed chromosomal disorder in newborns. The incidence is 1:792 live births. The article describes the irregularities and characteristics found in trisomy 21, which greatly affect the functioning of the stomatognathic system. The most significant disorders include the following: false macroglossia, muscular hypotonia and gothic palate. These abnormalities affect articulation, breathing, food intake, and swallowing. We analyzed the morphological characteristics of the craniofacial region in children with DS based on the current literature review. The following databases were used for the analysis: MEDLINE (via PubMed), Scopus, Infona, and Dentistry & Oral Sciences Source. In the course of the study, 199 pieces of literature were analyzed; the analysis also included 18 articles on children and adults with DS. It also took into account the structure of the palate, dental and skeletal defects, size of the tongue, muscular hypotonia, and temporomandibular joint dysfunction. Down syndrome is still a current subject of research. Although macroglossia, hypotonia, malocclusion, and temporomandibular joint abnormalities are not features exclusive to DS, numerous dysfunctions and parafunctions as well as retarded psychomotor development greatly complicate the treatment. Therefore, interdisciplinary treatment of patients with trisomy 21 and early treatment in the first months of life with the use of the Castillo-Morales plate are very important, as they ensure better adaptation to the subsequently used apparatus and reduce the risk of disorders of the stomatognathic system.

The aim of this article was to present a characteristic clinical image of Melnick–Needles syndrome using an example of an 11.5-year-old female patient treated at the Facial Congenital Disorders Outpatient Clinic as well as to present the actual literature review of the surgical treatment. The patient was diagnosed with several characteristics typical for Melnick–Needles syndrome: single-sided hearing loss, malocclusion, and facial dysmorphism, among others. Due to malocclusion and facial dysmorphism, the patient with Melnick–Needles syndrome requires orthodontic treatment with surgical intervention. Mandibular distraction with fixed appliance treatment is a recommended treatment protocol.

Objective The effect of orange juice and Coca Cola ® on the release of metal ions from fixed orthodontic appliances. Materials and methods A continuous flow system designed for in vitro testing of orthodontic appliances was used. Orange juice/Coca Cola ® was flowing through the system alternately with artificial saliva for 5.5 and 18.5 h, respectively. The collected samples underwent a multielemental ICP-OES analysis in order to determine the metal ions release pattern in time. Results The total mass of ions released from the appliance into orange juice and Coca Cola ® (respectively) during the experiment was calculated (μg): Ni (15.33; 37.75), Cr (3.604; 1.052), Fe (48.42; ≥156.1), Cu (57.87, 32.91), Mn (9.164; 41.16), Mo (9.999; 30.12), and Cd (0.5967; 2.173). Conclusions It was found that orange juice did not intensify the release of metal ions from orthodontic appliances, whereas Coca Cola ® caused increased release of Ni ions.

Aim. The aim of this study was to assess the electrical activity of temporalis and masseter muscles in children with cleft lip and palate (CLP) and pain-related temporomandibular disorders (TMD-P). Methods. The sample consisted of 31 CLP patients with a TMD-P (mean age 9.5 ± 1.8 years) and 32 CLP subjects with no TMD (mean age 9.2 ± 1.7 years). The children were assessed for the presence of temporomandibular disorders (TMD) using Axis I of the Research Diagnostic Criteria for TMD (RDC/TMD). Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany) in the mandibular rest position and during maximum voluntary contraction (MVC). Results. The rest activity of the temporalis and masseter muscles was significantly higher in TMD-P group compared with non-TMD children. A significant decrease in temporalis muscle activity during MVC was observed in TMD-P patients. There was a significant increase in the Asymmetry Index for temporalis and masseter muscle rest activity in the TMD-P group. Conclusion. Cleft children diagnosed with TMD-P have altered masticatory muscle activity, and this can affect their muscle function.

The objective was to evaluate metal ion accumulation in hair of patients undergoing orthodontic treatment with fixed appliances in time. The patients (N = 47) participated in a questionnaire survey. Hair sampling was performed at the beginning and in the 4th, 8th, and 12th month of the treatment. The content of metals (Cr, Ni, Fe) in hair was analyzed by ICP-OES equipped with USN nebulizer. The peak release of Cr and Fe occurred after 4 months of the treatment, and the peak release of Ni gradually increased throughout the whole year of the therapy. During 1 year treatment, an average accumulation of metals in hair tissue was 7.42 ± 14.19 μg of Ni, 8.94 ± 13.1 μg of Cr, and 131 ± 279 μg of Fe. The mean content of Cr was higher than the 90th percentile value for this element. The upper limit of literature reference ranges for Cr, Ni, and Fe in hair was not exceeded. The value of exposure (kinetics and dose) of orthodontic patients to metal ions released from orthodontic appliances can be assessed by hair mineral analysis. The content of Cr was statistically significantly higher during the treatment than before the beginning of therapy.

OBJECTIVE: To investigate the release of metal ions from an orthodontic appliance in tests on animals (pigs). MATERIALS AND METHODS: An animal test was conducted on 24 pigs divided equally into an experimental and a control group. In total, 12 sets of experimental orthodontic plates were surgically inserted into pig snouts in the experimental group for 6 months. Noninvasive matrices (hair [0, 3, and 6 months]) and invasive matrices (kidneys, liver, lungs, aorta, and oral mucosa) were collected for multi-elemental analysis (inductively coupled plasma optical emission spectrometry) from the experimental and control groups. RESULTS: The greatest differences in the content of toxic metals were found in the aorta (Ni level was 4.8 times higher in experimental than in the control group), in the cheek (Ni 3.5 times higher), and in the hair sampled after 3 months (Cr 3.4 times higher). CONCLUSIONS: The obtained data indicate that the products of corrosion have passed into selected tissues of pigs; however, the doses of toxic metal ions released from the appliance did not reach toxic levels.

BACKGROUND During orthodontic treatment, the various elements that constitute the fixed appliance undergo different processes. As a result of a change of the surface, elution/coverage of metals on the surface can be observed in the process of corrosion/passivation. MATERIAL AND METHODS Scanning electron microscopy with an energy-dispersive X-ray analytical system (SEM-EDX) was used to analyze the composition of stainless steel elements of orthodontic fixed appliances (before and after orthodontic treatment), to obtain the composition of the surface of the elements. The analyzed elements were: brackets (Victory Series APC PLUS 022, 3M Unitek, Monrovia, CA, USA); wires (0.017×0.025, 3M Unitek, Monrovia, CA, USA); and bands (37+, 3M Unitek, Monrovia, CA, USA). RESULTS The results showed a decrease of chromium and iron contribution to the surface, with increase of oxygen content in used vs. new elements of the appliance. CONCLUSIONS Our results confirm the formation of oxides (passivation layer) on the surface of stainless steel as a result of the presence of the orthodontic appliance in patients' oral cavities.

BACKGROUND Cleft lip and/or palate is the most frequent congenital abnormality occurring in the craniofacial region and is often associated with numerous dental defects such as tooth agenesis, supernumerary teeth, microdontia, taurodontism, crown malformations, or delay in eruption. The prevalence of hypodontia in cleft-affected patients is much higher in comparison with a healthy population. The aim of this study was to evaluate the prevalence of second premolar hypodontia in patients with cleft lip and/or palate. MATERIAL AND METHODS We performed a retrospective, evaluation of panoramic radiographs and dental casts in the Department of Dentofacial Orthopeadics and Orthodontics, Wroclaw Medical University. Two independent observers evaluated the records of 469 patients with various types of clefts and analyzed dental casts and panoramic radiographs. RESULTS 202 individuals met inclusion criteria. The sample comprised 120 UCLP patients, 38 BCLP patients, 28 CP patients, and 17 CLA patients. Hypodontia in the premolar region was observed in 39 individuals (19.3%). A total number of 58 second premolars were missing, of which 35 were maxillary second premolars (U5) and 23 were mandibular second premolars (L5). CONCLUSIONS Estimated hypodontia in the Polish CL/P sample was considerably higher than the hypodontia in permanent dentition reported for a European healthy population. The number of congenitally missing second premolars was higher in the maxillary arch than in the mandibular.

Background The lack of systematic review on reference values of elements in human hair with the consideration of methodological approach. The absence of worldwide accepted and implemented universal reference ranges causes that hair mineral analysis has not become yet a reliable and useful method of assessment of nutritional status and exposure of individuals. Objectives Systematic review of reference values of elements in human hair. Data sources PubMed, ISI Web of Knowledge, Scopus. Study eligibility criteria Humans, hair mineral analysis, elements or minerals, reference values, original studies. Results The number of studies screened and assessed for eligibility was 52. Eventually, included in the review were 5 papers. The studies report reference ranges for the content of elements in hair: macroelements, microelements, toxic elements and other elements. Reference ranges were elaborated for different populations in the years 2000–2012. The analytical methodology differed, in particular sample preparation, digestion and analysis (ICP-AES, ICP-MS). Consequently, the levels of hair minerals reported as reference values varied. Conclusions It is necessary to elaborate the standard procedures and furtherly validate hair mineral analysis and deliver detailed methodology. Only then it would be possible to provide meaningful reference ranges and take advantage of the potential that lies in Hair Mineral Analysis as a medical diagnostic technique.

Background Hair analysis is used for estimation of the nutritional status of individuals. In the present work, a systematic review on the relation between the mineral composition of hair and the physical or mental disorders is discussed. Detailed information of examined populations, methods of sample preparations and analytical techniques are presented. Methods A systematic literature search in four electronic databases Scopus, PubMed, Web of Science and Medline (from 1997 to 2012/01/31) for English language articles was performed. In addition, a reference list and manual search was undertaken. Results The following number of studies was included: 66. Most of the authors reported that there exists a correlation between deficiency or excess of some elements in hair and occurrence of some diseases, such as: autism, cancer, hypertension, myocardial infarction, kidney disease and diabetes mellitus. However, not all results were consistent. Conclusions Most of the authors concluded that the profile of hair mineral imbalance might be useful as a diagnostic tool for the early diagnosis of many diseases. However, it seems that there is a need to standardize sample preparation procedures, in particular washing and mineralization methods.

The objective was to investigate the effect of dietary habits on the release of Cr and Ni ions from orthodontic appliances by hair mineral analysis. Patients (N = 47) underwent electronic questionnaire survey to investigate the effect of dietary habits on Cr and Ni levels in hair. The research was carried out on hair sampled at the beginning and in the 4th, 8th, and 12th months of the treatment. The content of Cr and Ni in the collected samples was determined by ICP-OES. The study showed that consumption of acidic dietary products may have the effect on increasing the release of Cr and Ni ions from orthodontic appliances. The release of Cr from orthodontic appliances in patients who consumed fruit juice, coffee, yoghurt, and vinegar was higher. The coefficients enabling comparison of metal ions release pattern at a given sampling points were defined. The comparison of the coefficients yielded the information on the possible magnification of metal ions released as the result of the additional factor consumption of acidic food or drink that intensifies metal ions release. The following magnification pattern was found for chromium: coffee (7.57 times) > yoghurt (2.53) > juice (1.86) > vinegar (1.08), and for nickel: vinegar (2.2) > coffee (1.22) > juice (1.05). Yoghurt did not intensify the release of nickel. Concluding, orthodontic patients should avoid drinking/eating coffee, yoghurt, fruit juices, and vinegar.

Purpose The aim of this study was to assess the electrical activity of the superior orbicularis oris muscle in children surgically treated for unilateral complete cleft lip and palate (UCCLP). Material and methods The sample comprised 45 patients 6.38–12.68 years of age with UCCLP and 40 subjects 6.61–11.71 years of age with no clefts. Electromyographical (EMG) recordings were taken with a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany) in the rest position and during saliva swallowing, lip protrusion and reciprocal compression of the lips, as well as while producing the phonemes /p/, /b/, and /m/ combined with the vowel /a/. Results The electrical activity of the upper lip during saliva swallowing and lip compression was significantly greater in the cleft group. Similar resting level activity was observed in both groups. During the production of the /p/, /b/, and /m/ phonemes combined with the vowel /a/ the results showed no significant differences in the EMG activity between children with UCCLP and noncleft subjects. Conclusion Patients with UCCLP have abnormal upper lip function characterized by increased activity of the superior orbicularis oris muscle during saliva swallowing and lip compression, and this may affect facial morphology.

In the present work, a systematic literature review on release of metal ions from orthodontic appliances under in vitro conditions is described. Detailed and schematic analysis of used materials and applied methods (immersion media, incubation time, temperature, and analytical techniques) is provided. The PubMed search identified 40 studies, among which eight met the selection criteria. One additional study was included in the review. All the authors agreed that the doses of released metal ions were far below the toxic level and the dietary intake. Although the concentrations of metal ions in immersion media greatly differed, the general conclusions were coherent. It must be underlined that the main disadvantage of in vitro tests was that the experimental setup did not reflect in vivo conditions, e.g., the presence of biofilm, which grows on the surface of the materials in oral cavity. The presence and activity of microflora to a large extent is responsible for the process of corrosion, in particular, biodeterioration. The further scheme of in vitro research should incorporate changeable conditions of oral cavity environment (pH, dynamic conditions-saliva flow) and the presence of microbiological flora (microbiological attack) in the experimental design and, first of all, the real proportions of appliance elements.

The paper discusses various approaches used to investigate biocompatibility by the analysis of metals release by the materials of which orthodontic appliances are made. Analysis of various biomarkers of exposure: saliva, serum, mucosa cells, or urine is used in in vivo tests. In this work, the techniques, results, and conclusions of original papers were compared by the implementation of the concept of a systematic review. The aim of the present work was to report the state-of-the-art in the research on methods used to assess exposure to trace metals from orthodontic appliances. The PubMed search identified 35 studies, among which nine met the selection criteria. The general conclusion in the studies was that metal ions were released mostly in the initial stage of the treatment. However, the majority of studies included 1-2 months long period and did not reflect long-term changes nor the impact of the complete treatment, the duration of which is several years, on the whole organism and the overall accumulation of metals from orthodontic appliances. In studies which evaluated nickel concentrations in blood and urine, long-term metal release was detected and significant differences were found. It leads to the conclusion that nickel ions are released from orthodontic appliances in measurable amounts to human organism.

The Objective The aim of the study was evaluation of metal ions (nickel and chromium) released from orthodontic appliances in cleft lip and palate patients and the usefulness of non-invasive matrices (saliva and hair). Materials and Methods The material studied consisted of 100 individuals, including 59 females and 41 males of 5 to 16 years of age, which were divided into 3 groups: experimental–patients with cleft lip and palate (36 individuals, the average treatment time 5.74 years); control group–patients without cleft lip and palate, during orthodontic treatment (32 individuals, the average treatment time 1.78 years) and the control group patients without cleft lip and palate, without any orthodontic appliances (32 individuals). Samples (saliva, hair) were collected and subjects underwent a survey by questionnaire. Multi-elemental analyses of the composition of non-invasive matrices was conducted in an accredited laboratory by inductively coupled plasma spectrometry technique ICP-OES. The results were reported as mean contents of particular elements (Cd, Cr, Cu, Fe, Mn, Mo, Ni, Si) in hair and in saliva. Results The concentration of Cr, Ni, Fe and Cu ions in saliva of cleft lip and palate patients were several times higher as compared with not treated orthodontically control groups and higher than in the group with orthodontic appliances. Among the assessed matrices, hair of cleft lip and palate patients seem to be not a meaningful biomarker. Conclusion It was found that orthodontic appliances used in long-term treatment of cleft lip and palate patients do not release toxic levels of Cr and Ni ions.

In the present work, the biocompatibility of orthodontic devices was tested by the propagation of human osteoblasts. A different methodological approach was applied. Since the materials used in human and veterinary orthodontics (not in implantology) had been tested, osteoblasts were not implanted on the surface of the biomaterial, but have been cultured in the medium containing the products of corrosion. In the present work, osteoblasts were propagated in the medium spiked with Ni(II) salt versus the control. Osteoblast cells (live, dead, and total) were counted under light microscope. The statistical significance of the differences between the experimental and control groups were evaluated (P < 0.05). Based on the number of live, dead, and total cells, the viability and proliferation were determined. A slight cytotoxic effect of Ni(II) ions at the studied concentration was confirmed. The mean viability was 7% lower in the experimental versus the control group (the difference was statistically significant), while the change of proliferation was not significant.