Does daily wear time of Twin Block reliably predict its efficiency of class II treatment?

PURPOSE: The objective of this study was to investigate how daily wear time (DWT) influences class II malocclusion treatment efficiency. MATERIALS AND METHODS: The study group consisted of 55 patients (mean age 10.4 years) diagnosed with a class II/1 malocclusion. Twin block appliances, with built-in Theramon® microsensors (MC Technology, Hargelsberg, Austria) to monitor patients' cooperation (daily wear time assessment), were used for treatment. Cephalograms were taken and the following initial and final measurements were compared: Co-Gn, Co-Go, Co-Olp, Pg-Olp, WITS, SNA, SNB, ANB, Co-Go-Me, overjet, molar and canine relationships. The Shapiro-Wilk test, Wilcoxon signed-rank test, Student's t-test, Levene's test, Mann-Whitney U test, Kruskal-Wallis test, χ2 test, and Spearman's rank correlation coefficient with p < 0.05 set as the statistical significance level were used to determine the correlation of the outcomes with DWT; a ROC (receiver operating characteristic) curve was calculated to illustrate diagnostic ability of the binary classifier system. RESULTS: DWT was very highly positively correlated with change of the Pg-Olp parameter and highly with an improvement in the ANB, SNA, and SNB angles, an increase in the WITS parameter and an increase in Co-Gn distance. DWTs < 7.5 h correlated with significantly less improvement of the investigated variables. However, DWT > 7.5 h did not significantly correlate with the improvement of the overjet and most of the linear parameters in the mandible. The ROC curve and its AUC (area under curve) allowed the determination of a DWT of 7 h and 48 min to be capable of establishing a class I relationship with 83% probability. CONCLUSIONS: Class II treatment efficiency was influenced by DWT; an 8 h threshold value had an 83% probability of establishing a class I relationship.

Factors influencing an eruption of teeth associated with a dentigerous cyst: a systematic review and meta-analysis.

BACKGROUND: A dentigerous cyst (DC) is a pathology embracing the crown of an unerupted tooth at risk of malignant transformation. The causal tooth is usually removed together with the cyst. However, if there are orthodontic contraindications for extraction, two questions arise. (1) Which factors favor spontaneous eruption? (2) Which factors imply the necessity of applying orthodontic traction? This systematic review aimed to identify factors conducive/inconducive to the spontaneous eruption of teeth after dentigerous cyst marsupialization. METHODS: In accordance with the PRISMA guidelines, the main research question was defined in the PICO format (P: patients with dentigerous cysts; I: spontaneous tooth eruption after surgical DC treatment; C: lack of a spontaneous tooth eruption after surgical DC treatment; O: determining factors potentially influencing spontaneous tooth eruption). The MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched for keywords combining dentigerous/odontogenic/follicular cysts with teeth and/or orthodontics, as well as human teeth and eruption patterns/intervals/periods/durations. The following data were extracted from the qualified articles (4 out of 3005 found initially): the rate of tooth eruption after surgical treatment of the cyst, the age and sex of the patients, the perpendicular projection distance between the top of the tooth cusp and the edge of the alveolar process, tooth angulation, the root formation stage, the cyst area, and the eruption space. The articles were subjected to risk of bias and quality analyses with the ROBINS-I protocol and the modified Newcastle-Ottawa QAS, respectively. Meta-analyses were performed with both fixed and random effects models. The GRADE approach was used to evaluate the quality of the evidence. The systematic review was registered in PROSPERO under ID CRD42020189044. RESULTS: Nearly 62% of DC-associated premolars erupted spontaneously after cyst marsupialization/decompression. Young age (mean = 10 years) and root formation not exceeding 1/2 of its fully developed length were the factors likely to favor spontaneous eruption. CONCLUSION: The small number of published studies, as well as their heterogeneity and the critical risk of bias, did not allow the creation of evidence-based protocols for managing teeth with DC after marsupialization. More high-quality research is needed to draw more reliable conclusions.

A Clinical Comparison of Failure Rates of Metallic and Ceramic Brackets: A Twelve-Month Study.

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.

Hypodontia - not only an orthodontic problem.

BACKGROUND: The meta-analysis of the data collected in the years 1939-1993 clearly shows an increasing incidence of hypodontia. The disorder is characterized by a congenital absence of deciduous or permanent teeth. It is a significant esthetical and functional problem, which may negatively affect the patient's psychosocial development. OBJECTIVES: The aim of the study was to determine the scale of hypodontia using a sample of Polish orthodontic patients. MATERIAL AND METHODS: The orthopantomograms and medical records of 674 patients aged 6-15 years (376 girls and 298 boys) were analyzed in order to identify dental agenesis. Deciduous and wisdom teeth were excluded from the study. Data regarding gender, the location of the disorder as well as the number and type of missing buds was recorded. RESULTS: Hypodontia was found in 11.6% of the subjects (7.6% girls and 4% boys), more often in the mandible (44.9%) than in the maxilla (28.2%) or in both jaws (26.9%), and these differences were statistically significant (p = 0.096). The occurrence rates of uniand bilateral hypodontia were similar: 51.3% and 48.7%, respectively. The incidence of left-sided hypodontia (37.2%) significantly prevailed over rightsided hypodontia (14.1%) (p < 0.01). Tooth 35 was the most frequently missing one (13.5%). CONCLUSIONS: The large discrepancy in hypodontia prevalence indicates that geographical differences and varying sample sizes greatly affect the results of studies. The literature lacks comprehensive studies regarding hypodontia in Poland. More studies with similar sample sizes and selection criteria need to be carried out. Through an early detection of hypodontia, it is possible to plan comprehensive, interdisciplinary treatment. Regardless of the discrepancies in the literature as to the exact location of the problem, hypodontia affects over 10% of the population of patients treated orthodontically, which justifies the need to study this issue.

Self-perception of smile attractiveness as a reliable predictor of increased patient compliance with an orthodontist.

BACKGROUND: Predicting the cooperation of orthodontic patients seems to be of the utmost importance for successful results in treatment with removable appliances, especially if their cost is to be covered from public funding. Therefore, the issue of unbiased pre-treatment assessment of cooperation still calls for an investigation. OBJECTIVES: The objective of this study was to check whether smile attractiveness and its importance, subjectively evaluated by the patients/their caregivers, are reliable predictors of a patient's compliance during treatment with removable appliances. MATERIAL AND METHODS: The study group comprised 97 patients aged 9-12 years, treated with active plates or twin-blocks, equipped with the TheraMon® system. Before treatment, the caregivers and the patients filled out the questionnaires ranking both of the investigated variables. After 9 months of treatment, we analyzed the correlations of the daily wear time (DWT) and other variables. RESULTS: The analysis revealed the following: no relevance of the DWT to the type of removable appliances; negative correlation between the DWT and smile attractiveness assessed by the children and their caregivers; evidently elongated DWT (up to 9.68 h in children), who, together with the caregivers, evaluated their smile attractiveness as poor; coherence of children's and their caregivers' responses evaluating smile attractiveness and its importance, as well as the lack of consistency when comparing responses provided separately by the children and their caregivers. CONCLUSIONS: Application of the TheraMon® sensors objectively proved that the patient's smile attractiveness ranked subjectively as low predicts the orthodontic patient's irreproachable cooperation. Therefore, our easy-to-use questionnaire calls for changing the protocol regarding the wearing time of removable appliances during treatment and introducing an evidence-based policy of reimbursement for such therapy from public funds. Further investigation of the effectiveness of removable appliances worn shorter than previously presumed and of the motivation to continue treatment, once smile attractiveness has been improved, is necessary.

Canine substitution of congenitally missing maxillary lateral incisors in Class I and Class III malocclusions by using skeletal anchorage.

INTRODUCTION: This prospective cohort study aimed to evaluate canine substitution supported by skeletal anchorage as a viable treatment protocol for patients with maxillary lateral incisor agenesis (MLIA) and skeletal Class I or Class III. METHODS: Patients (n = 30) who met the following criteria were recruited: (1) bilateral MLIA or unilateral MLIA with a riziform contralateral incisor with a planned extraction; (2) skeletal Class I or Class III; and (3) dentoalveolar discrepancy in the mandible <5 mm. The archwire sequence routine was administered, combined with a rapid palatal expander, temporary intraoral skeletal anchorage device, and intermaxillary traction with Class III elastics. The results of the cephalometric analyses, peer assessment rating indexes, and the patient's smile self-evaluation using the visual analog scale were compared between initial and final treatments. RESULTS: This study indicated that closing the space in patients with Class I or Class III malocclusion by using temporary intraoral skeletal anchorage devices in the mandible, along with Class III elastics, yielded satisfactory outcomes. Proper occlusion was established by mesialization of the maxillary teeth and correction of the intermaxillary discrepancy, thereby yielding beneficial and significant cephalometric changes after the treatment. The soft tissue profile was maintained when it was harmonious before the treatment and improved posttreatment in patients in whom the profile was initially inharmonious. All occlusions improved, as evidenced by the peer assessment rating index. Smile esthetics were also enhanced after orthodontic treatment for all patients. CONCLUSIONS: Canine substitution may be safely offered to patients with Class I and Class III skeletal pattern and MLIA.

Influence of antibiotic prophylaxis on the stability of orthodontic microimplants: A pilot randomized controlled trial.

INTRODUCTION: The aims of this 2-arm parallel pilot randomized controlled trial were to investigate the influence of antibiotic prophylaxis on the stability of orthodontic microimplants and to evaluate the efficacy of systemic inflammatory marker measurements in detecting infections in tissues surrounding microscrews. METHODS: Orthodontic patients requiring en-masse distalization in the maxilla received antibiotics or a placebo before microimplant placement. Eligibility criteria included 13 years of age, and good general and oral health. Exclusion criteria comprised allergy to antibiotics, severe systemic allergy, heart and kidney diseases, and recent antibiotic treatment. Stability of the microimplants was the primary outcome; inflammation of the tissues surrounding the microscrews, pain related to the microimplantation, and serum levels of inflammatory markers were the secondary outcomes. Randomization in a 1:1 ratio was performed by auxilliary staff via a flip of a coin between 2 participants of the same sex and developmental stage, and the "winner" was allocated to the intervention group. Pharmaceutically prepared identical capsules with either amoxicillin (intervention) or glucose (control) given 1 hour before microimplant placement according to the allocation provided blinding of the participants. Subsequently, 1 clinician unaware of the allocation inserted the microimplants and assessed the outcomes, which simultaneously blinded the operator-assessor. Blood samples for laboratory analysis of inflammatory markers were collected a day before and 1, 3, and 7 days postoperatively. RESULTS: Out of 80 participants initially assessed for eligibility, 41 received the randomized allocation. Three patients were lost to follow-up. Eventually, data of 18 and 20 participants (mean age, 20.4 ± 5.9 years) were available for analysis in the intervention and control groups, in which 1 and 2 patients lost a microimplant, respectively, resulting in odds ratio of 0.53 (95% confidence interval [CI], 0.0084-11.23; P = 1.0). The odds ratio for inflammation development was 1.22 (95% CI, 0.34-4.38), and the odds ratio for feeling milder pain was 1.174 (95% CI, 0.350-3.941) in the intervention compared with the control group, but the result was not statistically significant (P = 0.758; P = 0.795, respectively). The inflammatory marker levels did not increase due to either microimplantation (procalcitonin, P = 0.445; C-reactive protein, P = 0.4) or peri-implantitis. Antibiotic prophylaxis slightly decreased the levels of the biomarkers in the intervention group; however, the results were not statistically significant (P = 0.68; P = 0.908, respectively). No harms caused by the microimplantation procedure or drug intake were noted. CONCLUSIONS: Antibiotics provided no benefit in terms of microimplant stability, inflammation of soft tissues, or postoperative pain in our pilot sample. Measurements of serum levels of inflammatory markers were inefficient in detecting soft tissue inflammations. These initial results should be interpreted with caution until validated by a large multicenter definitive trial. REGISTRATION: This trial was not registered. PROTOCOL: The protocol was not published before trial commencement. FUNDING: The trial was funded by Wroclaw Medical University; grant number pbmn91 and supported by Diagnostyka.

Objectively measured patient cooperation during early orthodontic treatment: Does psychology have an impact?

BACKGROUND: The effectiveness of orthodontic treatment with removable appliances arouses controversy concerning the level of patients' compliance. The compliance depends on factors controlled by the orthodontists, by the patients themselves and by their caregivers, and those beyond any control. OBJECTIVES: The purpose of this study was to assess the extent to which the personality traits of patients and their caregivers affect the cooperation in removable appliance therapy. MATERIAL AND METHODS: A total of 38 patients (19 boys, 19 girls) aged 9-12 years, presenting malocclusions suitable for removable appliance therapy were randomly selected. The EAS-C Temperament Questionnaire, Generalized Self-Efficacy Scale, NEO-Five Factor Inventory and Parental Attitude Scale developed by Plopa were employed to evaluate the patients' and the caregivers' temperamental dispositions. Electronic sensors were employed to objectively assess patients' cooperation. RESULTS: Statistical analysis revealed a high positive correlation between removable appliance wear time and the results of the GSES and the SPR-R, a strongly positive correlation between wear time and the NEOFFIC results and a strongly negative correlation between wear time and the EAS-C-Emo measurement. The level of a generalized sense of efficacy, conscientiousness and the severity of requirements imposed on the child were the factors related to the caregivers, positively correlating with patients' cooperation. CONCLUSIONS: The cooperation of children treated with removable appliances may be foreseen with observation of the patients' and their caregivers' traits. Objective evaluation of the patients' cooperation and psychological tests may be valuable tools for the re-assessment of the paradigm of early orthodontic treatment.

Orthodontic intrusion of periodontally-compromised maxillary incisors: 3-dimensional finite element method analysis.

BACKGROUND: Loading of the compromised periodontium with orthodontic forces produces different results than those achieved in patients with healthy periodontal support. Determining the force value at a level preventing further deterioration of the patient's periodontal status, thus delivering the most precisely individualized "dose" of loading, seems to be crucial for the successful intrusion of teeth with reduced periodontal support. OBJECTIVES: The aim of the study was to determine the range of force values efficiently intruding maxillary incisors without further compromising the initially-impaired periodontal status. Finite element analysis (FEA), allowing estimation of the stress and strain distribution, was the method of choice. MATERIAL AND METHODS: The CT scans of a periodontally-compromised patient were segmented using InVesalius software. A model - based on NURBS surfaces - was adjusted to the CT scans in order to obtain both smooth and natural curvatures of each model segment. All relevant tissues were modeled as separate volumes. The geometric model was discretized in order to create a numerical model for applying Ansys software (v. 15.07) and using APDL. The central incisors were loaded with external intrusive forces, ranging from 0.1 to 0.4 N. RESULTS: The simulation, performed iteratively, showed that even the lowest force value - 0.1 N - causes stress changes in the alveolus and on the root surfaces, with a tendency of stress increasing towards the bottom of the alveolus and root apex. It is also notable that during the application of forces of equal magnitude, the stress/strain distribution was significantly higher around tooth 21, which displayed the highest range of PDL reduction. Application of the same force level created a higher stress-strain response around tooth 21, and the characteristics were less homogenous. CONCLUSIONS: A force value of 0.1 N applied in vivo might produce the most effective tooth intrusion and bone modeling which favors bone defect regeneration.

Objectively measured compliance during early orthodontic treatment: Do treatment needs have an impact?

BACKGROUND: Objective assessment of daily wear time of removable appliances is possible, so the next step is to ascertain whether the severity of malocclusion influences patients' compliance. This could help resolve the controversy over the question of whether removable appliance therapy truly works. OBJECTIVES: The aim of the study was to investigate whether the patient's orthodontic treatment needs affect the cooperation between the patient and the doctor, and to find a correlation that could affect recommendations for orthodontic treatment. MATERIAL AND METHODS: The study involved 58 patients (29 boys, 29 girls) aged 9-12 years, who qualified for treatment with removable appliances equipped with a sensor system. The patients were divided into four groups according to their Index of Orthodontic Treatment Need dental health component scores. Over a 9-month period, data stored in the sensors were compared with the recommended daily wear time (DWT) of the appliances, and a statistical analysis was conducted. RESULTS: DWT differed considerably in all the groups. Statistically significant differences in the mean DWT values occurred only when extreme values of the IOTN DHC were compared. CONCLUSIONS: The degree of patient compliance depends to a small extent on the severity of malocclusion. Patients with mild malocclusion will probably be less likely to cooperate. Among patients with severe malocclusion, compliance may be unpredictable. Patient compliance is an important background factor that can explain a lot of the controversy over the effectiveness of treatment with removable appliances.

Effectiveness of orthodontic miniscrew implants in anchorage reinforcement during en-masse retraction: A systematic review and meta-analysis.

INTRODUCTION: The aim of this systematic review was to compare the effectiveness of orthodontic miniscrew implants-temporary intraoral skeletal anchorage devices (TISADs)-in anchorage reinforcement during en-masse retraction in relation to conventional methods of anchorage. METHODS: A search of PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science was performed. The keywords were orthodontic, mini-implants, miniscrews, miniplates, and temporary anchorage device. Relevant articles were assessed for quality according to Cochrane guidelines and the data extracted for statistical analysis. A meta-analysis of raw mean differences concerning anchorage loss, tipping of molars, retraction of incisors, tipping of incisors, and treatment duration was carried out. RESULTS: Initially, we retrieved 10,038 articles. The selection process finally resulted in 14 articles including 616 patients (451 female, 165 male) for detailed analysis. Quality of the included studies was assessed as moderate. Meta-analysis showed that use of TISADs facilitates better anchorage reinforcement compared with conventional methods. On average, TISADs enabled 1.86 mm more anchorage preservation than did conventional methods (P <0.001). CONCLUSIONS: The results of the meta-analysis showed that TISADs are more effective than conventional methods of anchorage reinforcement. The average difference of 2 mm seems not only statistically but also clinically significant. However, the results should be interpreted with caution because of the moderate quality of the included studies. More high-quality studies on this issue are necessary to enable drawing more reliable conclusions.

Reactive oxygen species in BCR-ABL1-expressing cells - relevance to chronic myeloid leukemia.

Chronic myeloid leukemia (CML) results from the t(9;22) reciprocal chromosomal translocation producing the BCR-ABL1 gene, conferring growth and proliferation advantages in the CML cells. CML progresses from chronic, often syndrome-free, to blast phase, fatal if not treated. Although the involvement of BCR-ABL1 in some signaling pathways is considered as the cause of CML, the mechanisms resulting in its progression are not completely known. However, BCR-ABL1 stimulates the production of reactive oxygen species (ROS), which levels increase with CML progression and induce BCR-ABL1 self-mutagenesis. Introducing imatinib and other tyrosine kinase inhibitors (TKIs) to CML therapy radically improved its outcome, but TKIs-resistance became an emerging problem. TKI resistance can be associated with even higher ROS production than in TKI-sensitive cells. Therefore, ROS-induced self-mutagenesis of BCR-ABL1 can be crucial for CML progression and TKI resistance and in this way should be taken into account in therapeutic strategies. As a continuous production of ROS by BCR-ABL1 would lead to its self-destruction and death of CML cells, there must be mechanisms controlling this phenomenon. These can be dependent on DNA repair, which is modulated by BCR-ABL1 and can be different in CML stem and progenitor cells. Altogether, the mechanisms of the involvement of BCR-ABL1 in ROS signaling can be engaged in CML progression and TKI-resistance and warrant further study.

Objectification of Orthodontic Treatment Needs: Does the Classification of Malocclusions or a History of Orthodontic Treatment Matter?

BACKGROUND: Orthodontic classifications make it possible to give an accurate diagnosis but do not indicate an objective orthodontic treatment need. In order to evaluate the need for treatment, it is necessary to use such indicators as the IOTN. OBJECTIVES: The aim of the study was to find (i) relationships between individual diagnosis and objective recommendations for treatment and (ii) an answer to the question whether and which occlusal anomalies play an important role in the objectification of treatment needs. MATERIAL AND METHODS: Two hundred three 18-year-old adolescents (104 girls, 99 boys) were examined. In order to recognize occlusal anomalies, the classifications proposed by Orlik-Grzybowska and Ackerman-Proffit were used. The occlusal anomalies were divided into three categories: belonging to both classifications, typical of OrlikGrzybowska classification and typical of Ackerman-Proffit classification. In order to determine the objective need for orthodontic treatment, the Dental Health Component (DHC) of the IOTN was used. RESULTS: The occurrence of the following malocclusions covered by both classifications, namely abnormal overjet, crossbite and Angle's class, had a statistically significant (p < 0.05) impact on an increase of treatment needs in the subjects (DHC > 3). As for the classification by Orlik-Grzybowska, dental malpositions and canine class significantly affected the need for orthodontic treatment, while in the case of the Ackerman-Proffit scheme, it was asymmetry and crowding. There was no statistically significant correlation between past orthodontic treatment and current orthodontic treatment need. CONCLUSIONS: IOTN may be affected by a greater number of occlusal anomalies than it was assumed. Orthodontic treatment received in the past slightly reduces the need for treatment in 18-year-olds.

Do Mechanical and Physicochemical Properties of Orthodontic NiTi Wires Remain Stable In Vivo?

Introduction and Aim. Exceptional properties of the NiTi archwires may be jeopardized by the oral cavity; thus its long-term effect on the mechanical and physiochemical properties of NiTi archwires was the aim of work. Material and Methods. Study group comprised sixty 0.016 × 0.022 NiTi archwires from the same manufacturer evaluated (group A) after the first 12 weeks of orthodontic treatment. 30 mm long pieces cut off from each wire prior to insertion formed the control group B. Obeying the strict rules of randomization, all samples were subjected to microscopic evaluation and nanoindentation test. Results. Both groups displayed substantial presence of nonmetallic inclusions. Heterogeneity of the structure and its alteration after usage were found in groups B and A, respectively. Conclusions. Long-term, reliable prediction of biomechanics of NiTi wires in vivo is impossible, especially new archwires from the same vendor display different physiochemical properties. Moreover, manufacturers have to decrease contamination in the production process in order to minimize risk of mutual negative influence of nickel-titanium archwires and oral environment.

Black stain and dental caries: a review of the literature.

Black stain is characterized as a dark line or an incomplete coalescence of dark dots localized on the cervical third of the tooth. Over the last century, the etiology of black stain has been the subject of much debate. Most of the studies concerning this issue were conducted in pediatric population. According to the reviewed articles published between 2001 and 2014, the prevalence of black stain varies from 2.4% to 18% with equal sex distribution. The majority of the authors confirm the correlation between the presence of black stain and lower caries experience. The microflora of this deposit is dominated by Actinomyces spp. and has lower cariogenic potential than nondiscolored dental plaque. Iron/copper and sulfur complexes are thought to be responsible for the dark color. In patients with black stain saliva has higher calcium concentrations and higher buffering capacity. Factors such as dietary habits, socioeconomic status, and iron supplementation may be contributing to the formation of black stain.

Do the NiTi low and constant force levels remain stable in vivo?

OBJECTIVE: The aim was to evaluate the alteration of the deactivation forces of the most commonly used nickel-titanium wires under long-lasting oral cavity environmental influence. MATERIALS AND METHODS: Randomized in vitro and in vivo trials of 540 pieces of orthodontic archwires, NeoSentalloy®, Copper NiTi® 35°C and Titanol Superelastic(®), round (0.016 inch), and rectangular (0.016 × 0.022 inch), were carried out. Randomization and blinding was achieved with 12-colour system that ensured encoding of key information on the tested specimens. Each of 270 patients (females, 18-20 years old, in the finishing stage of orthodontic treatment) received the piece of NiTi wire ligated piggyback, for a period of 4-6 weeks. Eventually, all samples were subjected to a three-point bending test. Data were statistically analysed at a 5 per cent significance level. RESULTS: In the group of the round used wires, when compared with the new ones, the deactivation force (F dav) values increased significantly for Titanol Superelastic®; the NeoSentalloy® and Copper NiTi® 35°C wires did not change their values of F dav. In the group of rectangular wires, F dav decreased for Titanol Superelastic®, but increased for NeoSentalloy® wires. The F dav values of the Copper NiTi® 35°C used wires practically did not change, but a remarkable increase of the standard deviation was noted. LIMITATIONS: No calculations concerning effectiveness of in vivo aligning of analysed wires were made. CONCLUSIONS: For the purpose of a 4-6-week aligning stage, round NeoSentalloy® with a diameter of 0.016 inches seems to be the wire of choice because of the low level of F dav.

Effect of the length of orthodontic mini-screw implants on their long-term stability: a prospective study.

OBJECTIVE: To analyze the influence of the length of temporary intraoral skeletal anchorage devices (TISAD/TAD) on their long-term stability in the mandible in a homogenous group of patients. MATERIALS AND METHODS: A group of generally healthy patients of the same gender (female) and with a statistically insignificant age difference (20-29 years) highly homogenous with respect to known factors affecting the success rate of TISAD/TAD was evaluated. One type of TISAD/TAD was applied (6- or 8-mm long). Each patient received both 6- and 8-mm-long TISAD/TAD in randomly selected mandibular quadrants: left or right. The long-term success rate of TISAD/TAD was analyzed. RESULTS: The 8-mm orthodontic mini-screw implants were significantly more stable than the 6-mm ones in the analyzed group. CONCLUSION: The length of the TISAD/TAD may be one of the factors that can affect the long-term success rate in the mandibles of 20- to 29-year-old women.