Elastic Ligatures Research Articles

Salivary pH Changes and Biofilm Formation During Active Orthodontic Treatment with Clear Aligners and Fixed Appliances

Objective: To examine salivary pH changes and the plaque formation in two different orthodontic treatments clinically. Methods: The study sample included 40 patients, who were divided into two groups according to the type of orthodontic appliance: Group CA, (n=15) clear aligners; Group FT, (n=25) fixed appliances. Group FT received both metal (FT/SS) and elastic ligatures (FT/EM) for 2 weeks respectively to test the effect of ligature type also. Salivary pH values, plaque index, and plaque percentage were measured at T0 (after scaling and polishing) and T1 (after 2 weeks). pH was measured with a digital caliper (HI 2211 pH/ORP Meter) and plaque was identified by a discoloring agent (Tri Plaque ID Gel). The Paired t-test, Independent t-test, Anova test and Pearson Correlation tests were used in the statistical analysis. Results: There was significant decrease in salivary pH values after two weeks of metal ligature in FT/SS. Plaque index and plaque percentage parameters showed significant incremental changes between groups with the least increase in CA, followed by FT/SS and FT/EM respectively. Conclusion: Different types of orthodontic treatment and ligatures significantly effected salivary pH and the amount of plaque formation during orthodontic treatment. Aligners had the least effect on salivary pH and plaque formation while fixed treatment with elastic ligature affected the most. Therefore, aligner treatment may be more beneficial for patients with compromised oral hygiene.

Comparative Analysis of the Frictional Resistance of Various Archwire-Ligature Combinations in Orthodontics.

Frictional resistance is a critical factor influencing the efficacy of orthodontic treatment. Archwire-ligature combinations play a significant role in determining frictional forces within the orthodontic system. This study aimed to conduct a comparative analysis of the frictional resistance exhibited by various archwire-ligature combinations commonly used in orthodontics. A total of five archwire-ligature combinations were evaluated in this study: stainless steel archwire with elastic ligatures, stainless steel archwire with metal ligatures, nickel-titanium archwire with elastic ligatures, nickel-titanium archwire with metal ligatures, and beta-titanium archwire with metal ligatures. Frictional resistance was measured using a universal testing machine under standardized conditions, with a constant load applied to simulate clinical conditions. The frictional resistance varied significantly among the different archwire-ligature combinations. The mean frictional resistance values (in arbitrary units) recorded were as follows: stainless steel archwire with elastic ligatures (X), stainless steel archwire with metal ligatures (Y), nickel-titanium archwire with elastic ligatures (Z), nickel-titanium archwire with metal ligatures (A), and beta-titanium archwire with metal ligatures (B). Statistical analysis revealed that combination A exhibited the lowest frictional resistance, followed by combination B, combination Z, combination X, and combination Y. The choice of archwire-ligature combination significantly affects the frictional resistance within the orthodontic system. Nickel-titanium archwires combined with metal ligatures demonstrated lower frictional resistance compared with stainless steel archwires, regardless of the ligature type. Among the combinations tested, nickel-titanium archwire with metal ligatures exhibited the lowest frictional resistance, suggesting its potential for reducing friction and improving treatment efficiency in orthodontic practice.

Evaluation of different mouthwashes through their effect on their influence on the force loss of orthodontic elastic ligatures

Background: In several orthodontic treatments, elastomeric chains are utilised to produce force, however, this force degrades over time, which may impact tooth mobility. This study aims to investigate how different mouthwashes (Chlorhexidine 0.2%, Sensodyne, and Listerine) may affect the force degradation of two different types of elastic ligatures (Ortho Matrix and 3M Unitek) through the amount of force remaining. Materials and methods: Two control groups and six experimental groups each included 600 pieces of the elastomeric chains Ortho matrix (OM) and 3M Unitek (3M). Pieces were stretched to a 25mm thickness, placed on pins set into an acrylic block, and kept at 37°C in artificial saliva. For the duration of the study, each of the test groups spent one minute immersed in one of three distinct kinds of mouthwash. Ten continuous thermocyclers with temperatures ranging from 5 to 55 degrees Celsius were performed each day, alternating between cold and hot water baths. While calculating the forces, we considered six different time intervals: the beginning, 24 hours, 1, 2, 4, and 6 weeks. The one-way analysis of variance (ANOVA) test and the t-test were used to compare the mean force of a number of different mouthwashes, elastomeric chains, and times. A value of 0.05 was chosen as the cutoff for statistical significance. Results: Over time, both types of elastomeric chains significantly lost force at 6 weeks (p<0.05). At all times, the 3M Unitek (3M) created more force than the Ortho matrix (OM) elastomeric chain. Compared to other mouthwashes, chlorhexidine mouthwash had a substantially less impact on force degradation, with discernible very simple change when compared to control groups (Artificial saliva). Conclusion: According to findings, the 3M Unitek offered a higher force level than the other sort of elastomeric chains, and there is a difference that is clinically significant between the two types of elastomeric chains. It is possible that the pH of the mouthwashes, as opposed to other substances, contributes to the gradual loss of power over time. Mouthwashes containing chlorhexidine had the third-smallest influence on the force degradation of elastomeric chains, after Sensodyne and Listerine..

Sinus pilonidalis—elastic ligature as an optimal outpatient treatment

Abstract Background The incidence of pilonidal sinus shows a steadily rising tendency, especially in the patient age group of up to 40 years. Treatment of this condition is often protracted involving lengthy sick leave and an increased risk of recurrence. The optimal treatment of pilonidal sinus remains open to debate, but it should focus on decreasing the length of hospitalization, promoting a rapid return to daily life, maintaining low pain levels, and keeping costs at a minimum. Materials and methods In our study conducted between 2017 and 2021, we focused on treatment of pilonidal sinus. We performed 50 elastic ligature procedures with a median observation time of 30 months. The patients were divided into three groups according to the characteristics of pilonidal sinus: (1) acute primary abscess; (2) acute recurrent abscess; and (3) chronic fistula. Results Out of a total of 50 patients with a subsequent 30-month follow-up, we observed complete recovery in 47 patients and recurrence in three patients. Return to work was possible immediately after the operation, with an average total treatment time of 1 month for complete healing of the defect. Conclusion The current results suggest that the technique of elastic ligature is a desirable solution for pilonidal sinus, because of the initial low costs, no need for hospitalization, and good patient tolerance.

Skeletal Anchorage in Treating Skeletal Class II Malocclusion in Growing Patients Using the Herbst Appliance

Skeletal Class II is a common malocclusion affecting the Caucasian population and characterized, in most cases, by a convex profile and mandibular retrusion. Therefore, the treatment plan often requires the use of functional appliances to promote mandibular advancement. In particular, the Herbst appliance is recommended because of its efficiency and minimal need for compliance. However, in addition to skeletal favorable effects, undesired dental compensations could prematurely reduce the overjet needed for a proper orthopedic outcome. The combination of this appliance with skeletal anchorage and elastic ligatures in the lower or both, in the upper and the lower arch, enables effective control of unfavorable tooth movements, improving the therapeutic potential of such a treatment. These improvements have significantly shifted the main focus on facial aesthetics rather than dental occlusion, with the creation of innovative treatment protocols and a new diagnostic approach to Class II malocclusion.

Development and Evaluation of a New Orthodontic Ligature: Frictional Force Analysis.

To evaluate and compare the friction of different ligature modes used in orthodontics, and to propose a new ligature model for conventional brackets ("H low-friction orthodontic ligature). Samples were randomly divided into seven experimental groups: (1) resin H ligature (H3D), designed by the authors of this study and produced in a 3D printer, with conventional bracket; (2) metal H ligature (HFM), with conventional bracket; (3) passive self-ligating bracket (SLP); (4) "8" low-friction unconventional elastic (LT8), with conventional bracket; (5) loose conventional metal ligature (MLS), with conventional bracket; (6) conventional metal ligature fully tightened (MLT), with conventional bracket; (7) conventional elastic ligature (CEL), with conventional bracket-control. All samples were subjected to mechanical static friction testing using the EMIC DL 2000 universal testing machine. To assess the normality requirement, the Shapiro-Wilk test was used, which showed a non-normal distribution for the means of the groups (p < 0.05). Therefore, statistical tests were performed to assess the existence of statistically significant differences between the groups through the Kruskal-Wallis, followed by Dunn's test, pairwise comparison, p < 0.05. The results obtained showed lower friction values for HFM (0.002 kgf), SLP (0.003 kgf), and LT8 (0.004 kgf)-these did not differ statistically from each other. These were followed by H3D (0.020 kgf), MLS (0.049 kgf), CEL (0.12 kgf), and, finally, MLT (0.21 kgf). The lowest friction value was found for the metal H ligature, similar to the self-ligating bracket and the "8" low-friction unconventional elastic. The resin H ligature presented intermediate friction values and the highest friction force was found for the MLT group.

A Novel Coating of Biosynthesized Silver Nanoparticles on Orthodontic Elastomeric Ligatures

Background: Fixed orthodontic appliances especially with orthodontic elastomeric ligatures can increase the risk for development of white spot lesions, which are often irreversible. Due to their huge surface area, silver nanoparticles are effective antimicrobials. Green synthesis employs the use of plant extracts such as Clove and Cardamom which possesses antimicrobial, antiinflammatory and antioxidant properties. Aim: This study aims to discover a novel approach to coat orthodontic elastomeric modules or ligatures with biosynthesized silver nanoparticles using clove and cardamom as plant extract. Materials and methods: Aqueous extract of cardamom and clove was prepared. Biosynthetic silver nanoparticles were synthesised by reacting silver nitrate ions with clove and cardamom extract (as bioreductant). Using a magnetic stirrer and a hot plate, silver nanoparticles (AgNPs) were synthesised directly on orthodontic elastomeric ligatures. Characterization of silver nanocoated elastomeric ligatures was done using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). Results: At the end of third day formation of AgNPs were reported by color shifting from orange-red to dark brown. Reducing silver ions to AgNPs, as shown by UV-vis spectroscopy, generated a peak at 462 nm. SEM and EDX confirms the presence of elemental silver on silver nanocoated elastomeric ligatures. Conclusion: An innovative coating technique incorporating magnetic stirrer along with a hot plate allows for the efficient coating of biosynthesized silver nanoparticles on orthodontic elastic ligatures. The SEM and EDX results indicate the structural integrity of the Ag nanoparticles on the biosynthetically produced orthodontic elastic ligatures is enhanced.

Frequency and Management of Accidental Incidents in Orthodontics.

The present study aims to define through questionnaires the frequency and the variety of accidental incidents occurring in orthodontic clinical practice among Greek practicing orthodontists. A questionnaire survey was conducted among orthodontists from the registry of orthodontists in Greece. The questionnaire was divided into two parts. The first part involved three questions relating to the socio-demographic status and the background of the orthodontist, and the second part concerned exclusively the frequency of accidental incidents that have occurred during clinical practice with three possible answers: never, once, more than once. From the 200 initially distributed questionnaires, 124 were finally completed and sent back (response rate: 62%). The results showed that orthodontists with more years of clinical practice had faced more accidental incidents. Among the ingestion incidents caused by foreign objects, the most frequently occurring was the ingestion of elastic separators, followed by the ingestion of elastic ligatures and ingestion of hooks. The most commonly reported traumatic incidents were the trauma-lesion of the mucosa by the orthodontic wire or part of it, followed by trauma-lesion by hooks and wire ligatures. The reported number of incidents with further complications and with patients referred to an emergency room was very low. The results of the present study determined a high frequency of accidental incidents among Greek orthodontists. The longer clinical experience was accompanied by more accidental incidents. Orthodontists, like other health professionals, must learn and continuously update their knowledge regarding the management protocols of medical emergencies.

An in vivo and in vitro study on the force degradation and surface morphology of the orthodontic elastic ligatures

The objective of this study was to investigate the characteristics of force degradation and surface morphology of 9 brands of elastic ligatures over 6 weeks, both invivo and invitro, to provide some reference for clinical selection of appropriate elastic ligatures and determination of appropriate follow-up visit time. Choosing 9 kinds of brands of elastic ligatures (American Orthodontics, Ormco, 3M Grey, TP Orthodontics, Xihu, Yahong, Creative, Protect, 3M dusty blue), which are common in the market. For the invivo study, 9 volunteers (5 males, 4 females, aged 22-26 years) were chosen to wear elastic ligature fixators, which were made to fix the elastic ligature in the mouth without bonding brackets on the teeth. The residual force and percentage of force degradation of elastic ligatures were estimated after 0, 1 hour, 2 hours, 8 hours, 1 day, 2 days, 1 week, 2 weeks, 4 weeks, and 6 weeks processed invivo and invitro (25°C dry air condition, 37°C artificial saliva, pH= 6.7 and oral environment); A 1-way analysis of variance and t test were used to identify statistical significance (P<0.05). The surface morphology of the initial state and after a 6-week process invivo and invitro were observed separately. The characteristics of force degradation and surface morphology of 9 brands of elastic ligatures were different over 6 weeks; With the extension of time, the tensile force declined, and the percentage of force degradation of all groups decreased sharply by about 9.1%-32.3% in the first day, then the rate reduced steadily. In addition, during the first day, the percentage of force degradation declined most sharply in the first hour (4.4%-16.5%). The percentage of force degradation of 9 elastic ligatures was reduced by about 11.3%-37.3% over 6 weeks in all groups. At the same time, the characteristics of force degradation in the same brand are that invivo> artificial saliva> air (P<0.05). After a 6-week process, the surface morphologic defects were aggravated under a scanning electron microscope, corresponding to the change of mechanical properties in each brand. The mechanical properties of elastic ligatures are reduced with time extension and decreased greater invivo than invitro; According to the characteristics of force degradation of different brands of elastic ligatures, clinicians can choose the proper elastic ligatures at different stages of treatment, and adjust the follow-up visit time appropriately. For example, in alignment and leveling, the elastic ligatures with slow force degradation, such as Ormco, TP, and so on, maybe more suitable to ensure close contact between the archwire and the bracket. In the space-closing stage, the elastic ligatures with fast force degradation may be more appropriate to reduce the friction between the archwire and the bracket, such as 3M Grey, Yahong, Protect, and so on.

Operating time for wire ligation with self-ligating and conventional brackets:A standardized in vitro study.

Operating time is one of the main advantages attributed from the literature to the use of self-ligating brackets (SLB). The aim of this study is to investigate the time needed for a complete archwire change procedure with conventional brackets (CB) and SLBs in a standardized in vitro research setting, comparing operators with different expertise. Thirty-three participants were divided into three equal groups: undergraduate students, postgraduate students, and orthodontists. Three sets of typodonts bonded with three types of brackets, including passive SLBs, active SLBs, and CBs using both steel and elastic ligatures were investigated. Operators had to insert, ligate, deligate, and remove wires in sets of typodonts representing an actual dentition before and after orthodontic treatment, mounted in phantoms. Archwire change procedure times were compared between the different bracket/ligation systems, between the before- and after-treatment typodonts, and between operators. There were significant differences between SLBs and CBs, the greatest difference being 11 min 16 s between passive SLBs and CBs ligated with metallic ligatures at T0, for the total archwire change procedure by the operators overall. For all the operators, there was a statistically significant difference in total archwire change procedure time between the systems. The undergraduate students were the slowest when using CBs, but they showed no significant difference compared to the other users when using SLBs. SLBs can offer a significant operating time reduction compared to CBs, and time saving is not dependent on the operator's experience and training.

The Effect of Ligature Type on Lateral Tooth Movement during Orthodontic Treatment with Lingual Appliances-An In Vitro Study.

(1) Background: One of the most challenging parts in lingual orthodontics is the control and correction of the tip of anterior teeth, due to the occlusal open vertical slot of the incisors in lingual systems. The presented experimental in-vitro study was performed to determine the maximal tipping moment of the anterior teeth between two types of lingual brackets, the Incognito™ Appliance System (Incognito, TOP-Service, Bad Essen, Germany) and Tip-Bar™ system (Incognito, TOP-Service, Bad Essen, Germany). Furthermore, twelve different ligation methods and two different ligature materials were investigated. (2) Methods: The measurement was performed by assessing the stiffness and ultimate strength of the ligature in a uniaxial material testing machine (Instron, Norwood, MA, USA) using a 0.025 × 0.018 inch stainless steel wire. (3) The results showed that the highest precision for control tipping of anterior teeth was determined for the 0.010 inch Stainless Steel Tie (Pelz and Partner). Furthermore, the Tip-Bar™ brackets increased the maximal moment by 33.8% for elastic and steel ligatures. (4) Conclusions: The lateral tooth movement is highly dependent on the type of ligature and applied material during orthodontic treatment with lingual appliances. The use of 0.010 inch steel ligatures and the Tip-Bar™ bracket design results in better alignment in the anterior teeth segment.

Color changes of esthetic elastomeric ligatures due to exogenic pigmentation

Vytautas Sabataitis1, Vilija Berlin2 1Institute of Odontology, Medical Faculty, Vilnius University, Vilnius, Lithuania 2Vilnius University Hospital Zalgiris Clinic, Vilnius, Lithuania Abstract Backround and aim of the work: a contemporary patient seeks to achieve the most aesthetically pleasing orthodontic treatment therefore chooses colorless elastic ligatures instead of metal ligatures. However, elastic ligatures tend to change their color due to food colorings and impair esthetics. Aim of this study is to evaluate and compare in vitro color change due to staining solutions of the most frequently used aesthetic orthodontic elastic ligatures offered by different companies in Lithuanian market. Materials and Methods: fourteen different types ligatures were immersed for 72 hours in four different solutions: distilled water (control), coffee, black tee, and wine. Ligatures’ color change was measured with spectrophotometer and evaluated by the Commission Internationale d’Éclairage color system and National Bureau of Standards units Results: Coffee was the most staining solution. Color change of all ligatures were from 4,32 (appreciable) to 24,71 (change to another color). Statistically significant and the smallest color change was observed in these ligatures: “Tooth” (GC), “Tooth” (America Orthodontics) and “Clear” (3M) with “Pearl” (American Orthodontics). The biggest color change was observed in “Clear” (American Orthodontics), “Clear” (GC), “Clear” (Ormco) and “Tooth” (Ormco) ligatures after the immersion. In group of all “Clear” ligatures only elastic ligatures by 3M showed statistically significant smallest colour alteration (p<0,01). Conclusion: all tested elastic orthodontic ligatures change their color after immersion in staining solutions and the color alteration is perceptible by human eye. Statistically significant color change between different types of ligatures was found. Keywords: Easthetic orthodontic, orthodontic appliances, Orthodontic ligatures.

A comparative analysis of efficiency between passive-self ligating brackets and conventional bracket system

Background: One main difference between self-ligating brackets and conventional bracket is elastic ligature, it is not used in self ligating brackets. The present study was conducted to know and compare efficiency between passive self-ligating bracket and conventional bracket system.Materials and Methods: Study was conducted on 30 patients. Two groups were formed.15 patients of both gender in each group. Patients selected were of moderate dental crowding. First group patient (group1) was treated with self-ligating pre-adjusted edgewise bracket (MBT 0.022) and second group (group2) with conventional pre-adjusted edgewise brackets (MBT 0.022).Results: Among the 30 patients 17 females and 13 males were selected. In group 1 male female ratio was 7:8 and in group 2 it was 6:9. Irregularity index (mm) in maxilla at T0 in group I was 2.65 and in group II was 3.15, at T1 was 0.56 in group I and 1.04 in group II and at T2 was 0.0 in both groups. The difference was significant (p

Accuracy of Different Complete-Arch Digital Scanning Techniques with a Combined Healing Abutment-Scan Body System.

Investigate the effects of three different complete-arch digital implant scanning techniques used with a combined healing abutment-scan body (CHA-SB) system on the accuracy (trueness and precision) and scan time. A poly(methyl methacrylate) master model simulating an edentulous maxilla was fabricated with four parallelly inserted dental implants. A CHA-SB system was attached to each implant. The model surface was scanned using a structured blue light industrial extraoral scanner to achieve a reference model standard tessellation language file (MRM-STL). Three different scanning techniques-(1) conventional technique with unmodified master model, (2) scan body splinting technique using orthodontic elastic ligatures and plastic splint materials, and (3) land-marking technique using pyramid-shaped glass-ceramic markers-were performed. Fourteen consecutive digital scans were made by using an intraoral scanner (IOS) for each technique, converted to an STL file, and superimposed on the MRM-STL. Trueness and precision were calculated for each technique. The scan time was also recorded. The data were analyzed with one-way analysis of variance (ANOVA) and Tukey honest significant difference (HSD) tests (α = .05). Effects of different scanning techniques on the trueness (distance and angular deviations; P < .001) and scan time (P = .002) were statistically significant. For precision, different scanning techniques had only a significant effect on the distance deviation (P < .001). Regarding trueness and precision, none of the scanning techniques was superior to others. The scan body splinting technique led to significantly less scan time.

The Effect of Extrinsic Factors on the Mechanical Behavior and Structure of Elastic Dental Ligatures and Chains.

Force provided by elastomers used in orthodontics can be affected by several factors present in the oral cavity. The aim of our study was to investigate the role of mouthwashes, toothbrushing, and smoking in the force decay of such elastomers. Tensile strength, changes in the force continuously exerted, and force decay of elastic chains (Ortho Organizer and Masel Short Power Chain) and elastic ligatures (Dentaurum and Masel) by two separate manufacturers were measured. Measurements were initially made on untreated elastics, followed by exposure to different environmental factors including cigarette smoke, toothbrushing (mechanical plaque control), and two different mouthwashes (chemical plaque control). Changes on the surface of the elastics were studied with scanning electron microscopy (SEM). Untreated Masel elastic ligature showed lower tensile strength than Dentaurum elastic ligature (2339 cN vs. 3660 cN), while significantly higher tensile strength was measured for Ortho Organizer elastic chains than Masel chains (2639 cN vs. 1324 cN). The decrease in the elastic force of Masel ligature was greater in response to all external factors compared to Dentaurum. Although brushing with toothpaste and toothbrush impacted the force of both Masel and Ortho organizer ligatures negatively, force degradation was more apparent in the case of the Ortho organizer. Surface changes were more visible when applying Curasept mouthrinse, however force decay was higher in the Corsodyl group. Mechanical and chemical plaque control can influence the tensile strength and force decay of orthodontic elastomers, which should be considered by selecting the elastomers or determining their changing interval for the practice.

Frictional Properties of the TiNbTaZrO Orthodontic Wire-A Laboratory Comparison to Popular Archwires.

Background. This study aimed to determine the kinetic frictional force (FF) of the recently produced TiNbTaZrO (Gummetal) orthodontic wire and compare it to the widely used wires of stainless steel (SS), nickel-titanium (NiTi), cobalt-chromium (CoCr) and titanium-molybdenum (TiMo) alloys. Methods. Five types of 0.016″ × 0.022″ wires were ligated with elastic ligatures to 0.018″ × 0.025″ SS brackets. The dynamic FFs between the brackets and ligated wires were measured utilizing a specialized tensile tester machine. Prior sample sizes for different archwires were conducted using power analysis for the general linear models. The existence of significant differences in FF between examined materials was initially confirmed by the one-way analysis of variance (ANOVA) with further evidence of pairwise differences by Tukey’s Honest Significant Difference test. Results. The pairwise differences between means of kinetic FFs for NiTi, CoCr, and Gummetal wires were not statistically significant (adjusted p-value > 0.05). Stainless steel alloy presented the lowest FF values significantly different from other groups (adjusted p-value < 0.05). On the contrary, TiMo wires showed significantly greater FFs (adjusted p-value < 0.05) than other alloys. Conclusions. Gummetal orthodontic wire exhibits similar frictional resistance as NiTi and CoCr wires. Bendable TiNbTaZrO wire might be used for sliding mechanics due to its favorable frictional properties.

Self ligating brackets: from past to present

Self-ligating brackets, as the name suggests, do not use any steel ligature wires or elastic ligature modules in holding the archwires into the bracket slots. Rather they have their own mechanics of holding the archwire, either by a clip already in the bracket or a sliding lock mechanic in the bracket. These brackets can be active or passive depending on how the wire is engaged in between the slot and the self-ligating mechanism. In this review article, various systems of self-ligating brackets have been shown as they have been introduced from the past since their introduction in the early 1930s to the present.

Does the exposure to cigarette smoke influence the colour stability and mechanical properties of different orthodontic elastic ligatures? – in vitro study

The aim of this study was to evaluate the colour stability and mechanical resistance of orthodontic elastic ligature exposed to cigarette smoke. Four commercial brands were used: Aditek® (GA), Eurodonto® (GE), Morelli® (GM) and Orthometric® (GO). Eight elastic ligature rings (for mechanical analysis) and eight 5×5mm fragments of the material (for colour stability analysis) were separated from each commercial brand for the control group (C) (n=64) and experimental group (E) (n=64). The control group was not exposed to cigarette smoke. Colourimetric status (CIEL*a*b* System) and light transmittance (% transmitted light) were evaluated using Vita Easyshade Compact and CM2600 spectrophotometers, respectively. The mechanical resistance was evaluated using a universal testing machine (EMIC DL), performing tensile testing (speed 5mm/min). The analyses occurred at the following times: T0, before exposure to the smoke; T1, after the 1st exposure; and T2, after the 2nd exposure to cigarette smoke. Comparison between the groups and evaluation of the time effect were performed with the ANOVA/Tukey (a=0.05) and ANOVA-MR tests with Bonferroni correction (α=0.016). Significant differences were only observed for colour stability in the GA-E (NBS T2: 15.94±1.88) and GM-E (NBS T2: 16.11±4.54) groups (P<0.05); transmittance in the GA-E group (T2-T0: -9.07±5.01) (P<0.016) and mechanical resistance in the GA-C group (T2-T0: -0.95±0.61N) (P<0.016). The orthodontic elastic ligatures were sensitive to the cigarette smoke exposure regarding to loss of mechanical strength properties and change in colour stability.

Color change and force degradation of esthetic orthodontic elastic ligatures submitted to foods from the Amazonian diet/ Alteração de cor e degradação de forças de ligaduras elásticas ortodônticas estéticas submetidas a alimentos da dieta amazonense

The aim was to evaluate the color changes (?E*) and force degradation (FD) of esthetic elastic ligatures when submitted to foods from the Amazonian diet. 150 segments of elastics (n=10) (American Orthodontics - AO Orthoclassic - OC and Orthometric - OM) were divided to be submitted 2 times a day, for 1min each immersion, for 28 days, in one of the solutions: AI- açaí, CU- cupuaçu, TU- tucumã, RW- red wine and DW- distilled water (control). FD was evaluated using a universal testing machine and ?E* by spectrophotometer. Qualitative analyses were performed by scanning electron microscopy (SEM). The readings were taken at the following times: T0 - initial, T1 - 24 hours, T2 - 14 and T3 - 28 days. The FD and ?E* data were analyzed by non-parametric statistics (p&lt;0.05). It was found that in the 3 brands, in all substances, there was a significant decrease in strength at T1 and at T2 there was an increase in strength. At T3, it is found that CU and DW promote significant differences from AI to OM and OC. For ?E* it was verified after 28 days in OM the ?E* was higher for the elastics submitted to TU and RW than in CU and DW. For OC, the variation was greater in DW than for TU and AI, whereas for AO there was no significant difference between the groups. for all brands there is a higher FD in the first 24 hours, with elastic recovery after this period; all solutions promote FD in the evaluated elastics and, for all brands tested, the ?E* is clinically unacceptable after 28 days of immersion.

Incidence of orthodontic appliance failures during the COVID-19 lockdown period

IntroductionAs a result of the rapid spread of the disease caused by severe acute respiratory syndrome coronavirus 2, the World Health Organization declared a global pandemic on March 11, 2020. Governments worldwide adopted various measures to stop or slow the spread of coronavirus disease 2019 (COVID-19). One widely used measure was lockdown; workers who could work from home were instructed to do so, and nonessential businesses—including dental clinics—were closed for weeks or months. The purpose of this investigation was to document the incidence of fixed orthodontic appliance failures and the periodontal health status of patients undergoing fixed orthodontic treatment during and after the lockdown period.MethodsThe sample comprised 350 orthodontic patients (mean age, 16.85 ± 2.59 years; 249 female, 101 male) who underwent orthodontic and periodontal examinations in Adıyaman, Turkey, after a mean lockdown period of 103.7 ± 21.3 days. Frequencies of an orthodontic bracket, elastic ligature, molar band, and miniscrew failures of oral ulcers were recorded, and periodontal parameters were assessed. The effects of sex, age, and the bracket systems used in the patients on the frequencies of these failures were analyzed.ResultsIt was revealed that 15.42% (n = 54) of all patients had ≥1 bracket bonding failure, and 8.16% (n = 4) of the patients with miniscrew implantation had ≥1 miniscrew failure. The incidence of bracket bonding failure was significantly higher in men than in women. No significant relationship was found between periodontal parameters and bracket bonding failure. Plaque and gingival scores were higher than those reported for a similar population before a lockdown.ConclusionsThe results indicated that orthodontic appliances might have higher frequencies of failure during a lockdown than normal times, and lockdown periods may worsen the periodontal health status of the patients.