The Hydrostatic Pressure Distribution in the Periodontal Ligament and the Risk of Root Resorption-A Finite Element Method (FEM) Study on the Nonlinear Innovative Model.

Excessive orthodontic force can induce inflammatory tooth root resorption due to sustained high stresses within the periodontal ligament (PDL). This study aimed to analyze the PDL pressures during upper incisor retraction using the en masse method with TISAD. The finite element method (FEM) ensured consistent conditions across cases. The models included bone geometry, adjacent teeth, PDL, and orthodontic hardware, analyzed with LS-Dyna. The pressure ranged from 0.37 to 2.5 kPa across the dental arch, with the central incisors bearing 55% of the load. The pressure distribution remained consistent regardless of the force or hook height. The critical pressure (4.7 kPa) was exceeded at 600-650 g force, with notable pressure (3.88 kPa) on the palatal root wall of the right central incisor. Utilizing 0.017 × 0.025 SS archwires in MBT 0.018 brackets provided good torque control and reduced the root resorption risk when forces of 180-200 g per side were applied, maintaining light to moderate stress. Triple forces may initiate resorption, highlighting the importance of nonlinear finite element analysis (FEA) for accurate oral cavity simulations.

Bone Remodeling of Maxilla after Retraction of Incisors during Orthodontic Treatment with Extraction of Premolars Based on CBCT Study: A Systematic Review.

Background: Incisor retraction is often a crucial phase in ongoing orthodontic treatment, with significant implications for alveolar remodeling mechanisms. There are two prevailing theories which seek to explain this. According to the first, teeth move with the bone, while according to the second, teeth move within the bone. This systematic review seeks to assess morphometric changes in the maxillary alveolar process resulting from incisor retraction following premolar extraction and to evaluate the potential for bone remodeling associated with orthodontic movement. Methods: The study was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following electronic databases were searched: PubMed, Google Scholar, Web of Science EMBASE and the Cochrane Central Register of Controlled Trials. The databases were searched using the following keywords: "Bone remodeling and retraction of incisors", "Alveolar bone and incisor retraction", "Bone thickness and incisor retraction", and "Bone changes and orthodontic treatment". Search filters were utilized to identify relevant papers and articles written in English and published during the last 10 years. Based on the information provided in their abstracts, papers and articles were selected according to the following criteria: randomized clinical trials (RCTs), controlled clinical prospective trials (CCTs), and retrospective studies. Articles unrelated to the study's scope or failing to meet inclusion criteria were excluded. These generally comprised individual case reports, case series reports, literature reviews, experimental studies, studies with limited data (including conference abstracts and journal writings), studies involving an unrepresentative group of patients (less than 10 patients), studies concerning patients with syndromes, and animal experiments. The remaining articles which were deemed relevant underwent comprehensive reference review and such journals as the American Journal of Orthodontics, Dentofacial Orthopedics, International Orthodontics, Journal of Clinical Orthodontics, and Angle Orthodontist were manually searched. Results: Seven articles meeting the inclusion criteria articles were selected for final evaluation, with a total of 284 participants, including 233 women and 51 men. During the analysis of the results included in the publications, a lack of homogeneity was observed, rendering a reliable statistical analysis and heterogeneity assessment unobtainable. Noteworthy disparities in methodologies and measurements posed a risk of drawing inappropriate conclusions. Consequently, emphasis was placed on qualitative analysis, emphasizing the need for standardization in future studies of a similar nature, to enable valid and comparable analyses. Conclusions: The research findings incorporated in this review demonstrate that significant bone loss occurs because of incisor retraction, which diminishes distance between the bone surface and the root surface on the palatal aspect. The magnitude of this change may vary, contingent upon both the extent of incisor displacement and alterations in their inclination, thereby affecting the positioning of the root tips. This change is significantly higher in adults than in growing adolescents. The rationale behind this assertion lies in the widely recognized phenomenon of declining cellular activity with advancing age. The decrease in the speed and intensity of cellular changes may explain the diminished capacity for remodeling as patient age increases. There is ongoing discourse regarding alterations in the volume of bone on the labial aspect of the alveolar process. Further research is necessary to measure whether bone remodeling during orthodontic movement is contingent upon other factors, such as the speed and biomechanics of retraction, the level of applied orthodontic force, and the patient age.

Comparison of Diagnostic Validity of Cephalometric Analyses of the ANB Angle and Tau Angle for Assessment of the Sagittal Relationship of Jaw and Mandible.

BACKGROUND: Cephalometric analysis is an essential tool used in orthodontic diagnosis and treatment planning. The aim of this study was to evaluate the reliability and repeatability of new cephalometric points introduced in Tau angle analysis, in contrast to the gold standard, which is the analysis of the ANB angle. For this purpose, an attempt was made to assess the repeatability and reliability of the introduction of anthropometric points by evaluating both inter- and intraobserver parameters, as well as the agreement among the orthodontists participating in the study. METHODS: Repeatability and reliability assessments for all six anthropometric points (N, A, B, T, M, G) used in the analysis of the ANB and Tau angles were conducted individually by 29 orthodontists. This assessment was performed in triplicate on the day of the study, on the day following the first study, and on the seventh day after the second study. Measurement errors for the ANB and Tau angles were evaluated using the Dahlberg formula and intraclass correlation coefficients (ICCs). RESULTS: The orthodontists in the study measured sagittal discrepancy significantly more accurately using the ANB angle compared to the Tau angle (p < 0.001). The Dahlberg error for measuring the Tau angle was three times greater than that for the ANB angle (p < 0.001). Additionally, the ICC for the Tau angle was more than 3.5 times smaller than that for the ANB angle, while the R&R error for Tau measurement was more than three times greater than that for the ANB angle (p < 0.001). CONCLUSIONS: The results of ANB angle measurements exhibit fewer errors in comparison to Tau angle measurements.

The Assessment of the Rank of Torque Control during Incisor Retraction and Its Impact on the Resorption of Maxillary Central Incisor Roots According to Incisive Canal Anatomy-Systematic Review.

BACKGROUND: Root resorption is one of the complications of orthodontic treatment, and has a varied and unclear aetiology. OBJECTIVE: To evaluate the relationship between upper incisor resorption and contact with the incisive canal and the risk of resorption during orthodontic treatment associated with upper incisor retraction and torque control. SEARCH METHODS: According to PRISMA guidelines, the main research question was defined in PICO. Scientific databases MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched for linking keywords: Resorption of roots incisive canal, Resorption of roots nasopalatine canal, Incisive canal retraction and Nasopalatine canal retraction. SELECTION CRITERIA: No time filters were applied due to the significantly limited number of studies. Publications in the English language were selected. Based on the information provided in the abstracts, articles were selected according to the following criteria: controlled clinical prospective trials and case reports. No randomised clinical trials (RCTs) or controlled clinical prospective trials (CCTs) were found. Articles unrelated to the topic of the planned study were excluded. The literature was reviewed, and the following journals were searched: American Journal of Orthodontics and Dentofacial Orthopedics, International Orthodontics, Journal of Clinical Orthodontics, Angle Orthodontist, Progress in Orthodontics, Orthodontics and Craniofacial Research, Journal of Orofacial Orthopedics, European Journal of Orthodontics and Korean Journal of Orthodontics. DATA COLLECTION AND ANALYSIS: The articles were subjected to risk of bias and quality assessment using the ROBINS-I tool. RESULTS: Four articles with a total of 164 participants were selected. In all studies, differences in root length were observed after contact with the incisive canal, which was statistically significant. CONCLUSIONS AND IMPLICATIONS: The contact of incisor roots with the incisive canal increases the risk of resorption of these roots. IC anatomy should be considered in orthodontic diagnosis using 3D imaging. The risk of resorption complications can be reduced by appropriate planning of the movement and extent of the incisor roots (torque control) and the possible use of incisor brackets with built-in greater angulation. Registration CRD42022354125.

Are Currently Selected Laboratory Animals Useful in the Research of How Female Hormones Influence Orthodontic Biomechanics?

Animal testing was and remains the only method of introducing a certain treatment and medical procedure on humans. On the other hand, animals have their rights resulting from applicable legal acts, including Directive 2010/63/EU and, indirectly, the World Medical Association International Code of Medical Ethics (Helsinki Declaration, 1975, amended 2000). Thus, the question arises whether the credibility of the results of hormonal and orthodontic tests obtained so far and their usefulness for the human population is scientifically justified and worth sacrificing laboratory animals for. Especially that, according to statistical data, about 50% of laboratory animals are euthanized at the conclusion of the experiments. The aim of this article was to determine whether animal experiments are scientifically or morally justified in bringing significant evidence in studies that may validate the influence of changes in the concentration of female hormones secreted by the ovaries in various phases of the menstrual cycle in young patients on the duration of an increased tooth movement rate in orthodontic treatment. Papers reporting the results of the original research into female hormones, either natural or exogeneous ones, likely to alternate the orthodontic tooth movement rate were critically evaluated in terms of animal selection. Thorough analysis supported by veterinary knowledge proved that none of the publications enabled an extrapolation of the results to humans. The evaluation of the relation between the rate of tooth movement upon loading with orthodontic forces and hormones either secreted during the menstrual cycle of women or released from the contraceptives already present in the market, does not require sacrificing laboratory animals.

Surface Evaluation of Aligners after Immersion in Coca-Cola and Orange Juice.

Orthodontic removable appliances made of transparent thermoplastic materials-aligners-are becoming increasingly popular in contemporary orthodontic practice. It is important for the clinician to fully understand the mechanical properties and behavior of the appliance used. Because of that, the aim of our study was to investigate the changes in aligner surface after immersion in Coca-Cola and orange juice. For surface evaluation, fractal analysis, texture analysis, and wetting angle measurement were performed. Statistically significant changes were found between some of the groups in the fractal dimension analysis. In texture analysis, all but one intergroup comparison showed statistically significant differences. For wetting angle assessment, statistically significant differences were found. These were, however, more numerous when assessing glycol droplets, rather than water droplets. Fractal dimension analysis confirmed a correlation between the intensity of changes in the aligner surface with immersion time in the liquids assessed. Texture analysis showed a high sensitivity to the changes in aligner surface. It failed, however, to reveal changes relative to immersion time. Wetting angle analysis revealed aligner surface degradation for Coca-Cola. It did not, however, prove the dependence of the intensity of this degradation as a function of time. Both Coca-Cola and orange juice can cause aligner surface degradation.

Evidence-based selection of orthodontic miniscrews, increasing their success rate in the mandibular buccal shelf. A randomized, prospective clinical trial.

BACKGROUND: Skeletal anchorage has made it possible to perform complex orthodontic tooth movements that are difficult or even impossible to achieve with conventional orthodontic treatment. Mandibular buccal shelf miniscrews, used for distalization, play a particularly important role in treatment of Class III malocclusion. Unfortunately, stability of the miniscrews placed in the mandible is still considered at higher risk of failure compared to other intraoral locations. The aim of our study was to determine the influence of the miniscrew size on their long-term stability, occurrence of oral mucosa inflammation and pain lasting over 48 h after implantation. METHODS: 184 Absoanchor® miniscrews (Dentos, South Korea) in two sizes: SH2018-10 (length 10 mm, ø 1.8-2.0 mm) and SH1514-08 (length 8 mm, ø 1.4-1.5 mm) were inserted in the mandibular buccal shelf in 92 Caucasians aged 20-50 years, diagnosed with Class III malocclusion that required en-masse distalization of the mandibular dentition. Data was statistically analyzed with the level of significance set at p = .05. RESULTS: 91.3% of the SH2018-10 and 75% of the SH1514-08 miniscrews were stable, and this difference was statistically significant (p < .05). Inflammation of the oral mucosa was noticed around both types of miniscrews and affected 50% of the SH2018-10 and 26.09% of the SH1514-08 group (p < .05). Pain lasting longer than 48 h after implantation was related to 60.87% and 20.65% of the SH2018-10 and the SH1514-08 miniscrews (p < .05), respectively. Inflammation associated with larger SH2018-10 miniscrews did not affect their stability (p > .05), contrary to the SH1514-08 ones (p < .05). When inflammation was present, the overall success rate declined to 64.29%, from 94.74% noted for TADs without inflammation. According to the log-rank test, smaller TADs failed significantly sooner than the larger ones (p = .002). CONCLUSION: Larger SH2018-10 miniscrews are the anchorage of choice for the mandibular buccal shelf, despite triggering inflammation and long-lasting pain significantly more often than the smaller ones. Therefore, this issue should be discussed with every patient prior to miniscrew use. Trial registration ID: ClinicalTrials.gov Identifier: NCT05280678 Date of Registration: 15/03/2022. Retrospectively registered.

Influence of Lip Projection and Chin Position on Facial Profile Preferences Among Various Layers of Polish Population. Part 1.

Purpose: This study aims to evaluate how the extent of altering lip projection in women and chin position in men influences the 22-year-old Caucasian's facial profile attractiveness, in relation to respondents' sex, age and place of residence. Materials and Methods: One female and one male orthognathic (SNA angle = 79-85°, Z angle = 75-78°) face profiles, with lips correctly positioned in relation to the E-line were photographed and digitally modified. This processing resulted in 30 photographs varying as for 1. the SNA angle determining orthognathic, prognathic (SNA angle >85°), or retrognathic (SNA angle <79°) profile and 2. lip projection/chin position: normal or protruded/retruded by 1 or 2 mm. The photographs were always shown in the same order to 418 respondents (306 women and 112 men) aged between 15 and 73 years, who provided their place of residence. The 11-point visual analogue scale (VAS) was used for the assessment of the facial profile attractiveness. Results: All respondents found the prognathic profile with correct lip position in woman and correct chin position in man most attractive. Each major deviation from the norm resulted in a decrease in the scores awarded. Men ranked rethrognathic profiles significantly (p < 0.05) higher than women. The respondents under and over 25 years also differred (p < 0.05) in their evaluation: the older viewers were more critical regarding all female profiles with an exception of the retrognathic profile with 2 mm lips protrusion. The respondents' place of residence did not affect the rating. Conclusion: 1 mm modification of lip projection and chin position significantly alter ranking the face profile attractiveness, thus any aesthetic medicine applied in this area requires extreme caution. Moreover, visualizing the results should be mandatory, especially in women older than 25 years of age, who are the most critical evaluators.

Orthodontic Compliance Assessment: A Systematic Review.

OBJECTIVES: The aim of this review was to determine whether the type of removable appliance, as well as the age and sex of the patient, may affect the extension or reduction of wear time by assessing the correlation between the mean actual and orthodontist-recommended wear times. METHODS: Randomised case control trials, cohort studies, case series, observational studies, reviews, and retrospective analyses were identified. The quality of the studies was assessed using the Cochrane Collaboration Tool and modified Newcastle-Ottawa Scale. The electronic databases Embase, PubMed, Scopus, and Web of Science were reviewed, and 542 articles were obtained, of which 31 were qualified for qualitative synthesis. The data from 1674 participants were collected and a weighted average was determined for the mean wear time of each appliance. RESULTS: Regardless of the type of extra- or intraoral appliances, mean wear time was shorter than recommended, although patients using intraoral appliances cooperated more. The best compliance was noted for Schwarz appliances (73.70%) and plate retainers (85%). There was no evidence of an influence of patients' age and sex on compliance during treatment. CONCLUSIONS: The considerable inconsistency and imprecision of articles could affect the reliability of the results. Previous studies analysing the effectiveness of treatment with removable appliances based on an arbitrarily assumed average wear time need to be revised in order to verify the actual wear time with the use of microsensors.

Methods of Anterior Torque Control during Retraction: A Systematic Review.

BACKGROUND: There are various methods of controlling the inclination of the incisors during retraction, but there is no evidence as to the advantages of some methods over others. The purpose of this systematic review and meta-analysis was to determine the effectiveness of the methods used to control torque during anterior teeth retraction. METHODS: In accordance with the PRISMA guidelines, the main research question was defined in the PICO format [P: patients with complete permanent dentition; I: the maxillary incisor torque after (I) and before I retraction with straight-wire appliance and different modes of torque control; O: statistically significant differences in torque values of the upper incisors after orthodontic treatment]. The MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched for keywords combining: retraction orthodontics, torque control orthodontics, torque orthodontics, inclination orthodontics, torque control retraction. 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. RESULTS: 13 articles were selected in which total number of 580 subjects took part. In all studies, incisors were retroclined during retraction by 2.46° (mean difference), which was statistically significant. Considering the articles separately, the differences in torque between the study group and the control group were statistically significant in six articles. The Q statistic was 36.25 with p = 0.0003 and I2 = 66.9%, which indicated a high level of study heterogeneity. CONCLUSION: Both properly performed corticotomy and en-masse retraction using orthodontic microimplants seem to be the most effective and scientifically validated methods of torque control. Further high-quality research is needed to perform better quality analyses and draw more reliable conclusions.

Changes in the Mandible Following Rapid Maxillary Expansion in Children with Class II Malocclusion: A Systematic Review.

OBJECTIVE: The aim of this systematic review was to determine whether rapid maxillary expansion (RME) allows favorable changes in the mandible during the treatment of class II malocclusion before the growth spurt. METHODS: A search of Pubmed/Medline, the Science Direct, and the Google Scholar database was performed. The keywords used were: orthodontics, rapid maxillary expansion, class II, and growing patients. Relevant articles were assessed for quality according to Cochrane guidelines, and then changes in SNA, SNB, ANB, NL-NSL (or SN-SNP.SNA), and ML-NSL (or SN-Go-Gn) relationships were analyzed. RESULTS: The selection process brought forth five articles, including 162 patients (91 females, 71 males) for detailed analysis. The quality of the evidence (GRADE) for comparisons and outcomes was assessed as moderate for SNB and ANB and as low or very low for other variables. CONCLUSIONS: The results of this systematic review showed that there is a small body of moderate-quality evidence for statistically and clinically favorable changes in SNB and ANB angles and a small body of low-quality evidence for changes in vertical parameters after RME.

New Sagittal and Vertical Cephalometric Analysis Methods: A Systematic Review.

Cephalometric analysis is an essential tool used in orthodontic diagnosis and treatment planning. The main objectives of correct cephalometric analysis include resolving anteroposterior and vertical maxillary and mandibular base discrepancies. For a diagnostic tool to be of value, it should be precise, reliable and reproducible. Unfortunately, according to some studies, the accuracy of input and, therefore, the diagnostic reliability of some of the points and measurements may not be satisfactory. To this end, new cephalometric measurements are being developed with increased precision. In order to properly and definitively determine the usefulness of a given measurement in cephalometric diagnosis, it is necessary to carry out a critical evaluation of available studies. The aim of this systematic review was to evaluate the available scientific literature describing new landmarks and reference linear and angular measurements of 2D cephalometric analyses assessing the sagittal and vertical discrepancy in the position of jaw bases since the last systematic review in 2013. The secondary aim was to assess the accuracy and reliability of new anthropometric landmarks and reference planes in relation to those used previously, and their instability in relation to growth and orthodontic tooth movements. To carry out the intended plan, electronic databases such as PubMed, Scholar Google, Web of Science and Pro Quest were searched using specific keywords. Initially, a total of 1451 articles were retrieved. Then, duplicate articles in all databases were excluded from the resulting publications. The results showed that despite such a high number of articles published in peer-reviewed scientific journals, only 12 studies on new cephalometric analyses in the sagittal plane and 4 studies on new cephalometric analyses in the horizontal plane met the criteria and, as a result, were included in the review.

The Use of Microsensors to Assess the Daily Wear Time of Removable Orthodontic Appliances: A Prospective Cohort Study.

Orthodontic treatment with removable appliances is still common in children and adolescents. However, their effectiveness depends primarily on the patients' compliance. Currently, it is possible to check the daily wear time (DWT) of the removable appliances using special microsensors. The aim of this prospective cohort study was to assess the degree of patients' compliance depending on the type of removable appliance used. In total, 167 patients (87 F, 80 M) were enrolled in the study and were treated with block appliances (Klammt, Twin-Block), Schwarz plates, and block appliances in combination with headgear. All patients were followed up for 6 months with the mean daily wear time checked at followup visits using TheraMon® microsensors fitted in the appliances. It has been shown that the type of appliance influences the patients' compliance. The DWT for the Twin Block was significantly longer compared to the DWT for the other appliances. Girls have been shown to wear removable appliances better than boys. It has been proven that the majority of patients do not follow the orthodontist's recommendations, wearing removable appliances for just over half of the recommended time. Microsensors can be used for objective verification of patients' compliance, which allows for a reliable assessment of the effectiveness of treatment with removable appliances.

Assessment of the reliability of measurements taken on digital orthodontic models obtained from scans of plaster models in laboratory scanners. A systematic review and meta-analysis.

BACKGROUND: In recent years, digital models have become increasingly popular among orthodontists, both for clinical and scientific purposes. It is, therefore, crucial to appropriately investigate their reliability. To this date, however, there has been no scientific, statistical investigation of their reliability as compared to the traditional gold standard-plaster models in the form of a meta-analysis. OBJECTIVES: To evaluate the reliability and reproducibility of measurements taken on digital orthodontic models obtained from scanning plaster models in laboratory scanners compared to measurements taken directly on plaster models. SEARCH METHODS: Multiple electronic databases (PubMed, Scopus, Web of Science, Google Scholar and Cochrane Central Register of Controlled Trials) were searched for articles with no year or language limitations. SELECTION CRITERIA: The included original papers should have dealt with the accuracy and repeatability of the measurements conducted on plaster and digital models derived from laboratory scanners. In order to provide an adequate statistical analysis, the studies should have provided sufficient data, that is the difference of means (MDs) with standard deviations (SDs) for analysed measurements. DATA COLLECTION AND ANALYSIS: In total, 25 types of non-standardised measurements were found in the evaluated studies. The quantitative analysis included papers that compared at least one of the parameters: upper/lower intermolar width, upper/lower intercanine width, overjet and overbite and provided standard deviation of the mean differences between measurements obtained on plaster and digital models from a laboratory scanner. RESULTS: GRADE and QUADAS tools were used to assess the quality of evidence, and they revealed substantial heterogeneity. Random-effects meta-analysis revealed no statistically significant differences for analysed measurements. Four of the analysed papers reported differences that may be considered clinically significant. CONCLUSIONS: No statistical significance between the direct measurements on plaster models and the digital ones taken from laboratory scanners could be identified by means of random-effects meta-analysis. REGISTRATION: The systematic review was registered in the PROSPERO database (ID CRD42020215411).

Surface Evaluation of Orthodontic Brackets Using Texture and Fractal Dimension Analysis.

The surface topography of orthodontic brackets can have a significant impact on both the effectiveness of the therapy and the behavior of these elements in the oral cavity environment. In this situation, striving to obtain the most uniform, smooth surface in a repeatable manner for each manufactured element should be a sine qua non condition for each supplier of orthodontic brackets. Therefore, it is necessary to analyze the surfaces of orthodontic brackets using different methods. One of them-that is relatively simple and repeatable-is the analysis of the fractal dimension and the analysis of the textures of the optical images on the surface. In the presented study, fractal dimension analysis and texture analysis were performed by selecting four brackets from three different manufacturers (Mini Sprint, Sprint, Nu-Edge, Orthos SS). The area of each bracket slot was analyzed at six predefined points. The smoothest and most uniform and reproducible surface structure was shown by the Mini Sprint bracket. On the other hand, Sprint brackets showed the least homogeneous and least repeatable surface structure.

Oral cancer awareness among patients at 3 university hospitals in Poland and Germany: A survey research.

BACKGROUND: The epidemic of cancer (including oral cancer) is a growing public health and economic problem in the European societies. A high percentage of patients who come for the appropriate treatment are in the late stages of advancement, often with nodal and/or distant metastases. The literature on the public oral cancer awareness in Poland and Germany is limited. OBJECTIVES: To investigate the levels of public awareness about the early symptoms and risk factors of oral cancer, and to analyze the findings in the context of the socioeconomic profiles of the subjects. MATERIAL AND METHODS: The survey consisted of a 20-item questionnaire divided into 4 sections: socioeconomic and demographic factors, the awareness of oral cancer, symptoms of oral cancer, and its risk factors. It was distributed to 465 adult patients in Poland (Wroclaw and Lódz) and Germany (Dresden). RESULTS: The response rate was 97.6%. Most of the respondents (65.4%) had heard of oral cancer. The sources of information were mainly the traditional mass media and the Internet, with only 23.8% of the respondents indicating doctors as a source of information about oral cancer. What is worrying, only about 1/5 of the participants in each of the 3 centers had an oral cancer examination last year. The awareness of oral cancer correlated positively with the age of the respondents and negatively with the size of the place of residence. Education level had no significant impact on declared knowledge. CONCLUSIONS: The results of this survey do not only show unsatisfactory levels of patients' awareness of the risk factors and symptoms of oral cancer but also emphasize the need to improve the level of healthcare concerning this disease, including screening programs.

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.

Antiadherent and antibacterial properties of TiO2-coated and TiO2:Ag-coated stainless steel orthodontic wires against S. mutans bacteria.

PURPOSE: Conventional orthodontic treatment with stainless steel orthodontic wires may be detrimental to oral health, as it contributes to demineralized lesions and increases adhesion and bacterial biofilm formation, which contributes to cavity development. An alternative that has been investigated to reduce the side effects of orthodontic treatment is the use of coating materials with antimicrobial nanoparticles. This study aims to evaluate the antiadherent and antibacterial properties of TiO2-coated and TiO2:Ag-coated stainless steel orthodontic wires against S. mutans bacteria. METHODS: In the sol-gel method, TiO2:Ag thin films were deposited on stainless steel orthodontic wires. Coated archwires were analyzed for their antibacterial and antiadherent properties. The evaluation of Streptococcus mutans adhesion to the orthodontic wires' surface was conducted according to the type of coating used, biofilm formation assay, and measurement of the pH of the bacterial community. RESULTS: In the microbiological test, the TiO2:Ag coatings revealed a statistically significant difference in terms of microbial adhesion and biofilm formation by Streptococcus mutans. The TiO2:Ag coating on stainless steel wire increased pH levels in the saliva environment. CONCLUSIONS: It can be concluded that antimicrobial orthodontic wires coated with silver TiO2 nanoparticles using the sol-gel thin film are a promising choice for improving orthodontic treatment.

Surface Evaluation of Orthodontic Wires Using Texture and Fractal Dimension Analysis.

Mechanical properties of orthodontic wires can have a very significant impact both on the resistance of the entire appliance to the oral cavity conditions and directly on the effectiveness of the therapy. Striving to achieve repeatability of mechanical characteristics of orthodontic wires of a given type should be an obligatory condition in their production. To achieve it, these components should be thoroughly analyzed using various mechanical tests. Twenty-four steel and nickel-titanium orthodontic wires from four different manufacturers were examined. Each wire was subjected to fractal dimension analysis and texture analysis. The two sides of each wire were compared against each other, as well as in terms of variation in the surface area for each wire type made by different manufacturers. Most wires showed significant variation in fractal dimension and texture, both when comparing two sides of the same wire and between individual wires of a given type made by a single manufacturer. When conducting research and clinically using orthodontic wires made of Ni-Ti alloys and stainless steel, it should be assumed that the surface of orthodontic wires shows a significant degree of variation, and wires of the same type from the same manufacturer may differ significantly in this respect.

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.