Mattress Coil Spring Fatigue and Weight-Bearing Support: Comparison of Weight-Bearing and Non-Weight-Bearing Springs.

OBJECTIVE: The purpose of this study was to compare the firmness of used mattress coil springs from the areas bearing greatest body weight versus areas subjected to little compression. METHODS: Weight-bearing springs (WBS) extracted from the center of the mattresses (N = 32), and non-weight-bearing springs (NWBS) extracted from the head/foot were of the same mattresses. To determine spring weakness, a 1296-g ingot was placed on the coil, and the compression distance was measured (cm). In addition, a gauge was used to measure the amount of pressure required to compress the coil springs a distance of 2 cm. Comparison between WBS and NWBS data were statistically treated using independent t tests and a 1-way analysis of variance. RESULTS: There were no significant group differences in weight or height in unloaded coils. However, there were significant (P < .05) differences in coil spring compression distance under load (WBS = 2.78 ± 0.34 cm; NWBS = 1.52 ± 0.39 cm) and force gauge compression (WBS = 1090.51 ± 88.42 g; NWBS = 1213.12 ± 71.38 g) between groups. CONCLUSION: This study found that WBSs were weaker when compressed than the NWBS from used mattresses, and such characteristics may not be visually apparent in a mattress when not in use. Thus, coil springs in bedding systems may eventually fail to provide the initial structural support after use. Such sagging may compromise sleep posture with accompanying poor sleep quality and quantity.

Innovative Application of Diathermy in Orthodontics: A Case Report.

INTRODUCTION: Several strategies have been proposed in the literature to accelerate tooth movement, many of which are invasive and have numerous side effects, such as surgical techniques (corticotomy and piezocision technique). This research investigates to what extent diathermy can accelerate the orthodontic alignment phase. MATERIALS AND METHODS: A patient with lower teeth crowding index of the same magnitude was selected. The orthodontic treatment with Nickel-Titanium (NiTi) thermal arc 0.015 in the lower arch was performed, associated with a weekly application of diathermy using the intraoral handpiece. The total duration of treatment was three weeks. During each session, an intraoral transducer was employed to stimulate the hard and soft tissues of the left dental hemiarch, which was also orthodontically aligned like the right one. RESULTS: Comparing the tooth movements of four elements of the two hemiarchies, it was found that, overall, the two teeth examined on the treated side underwent a more significant number of changes than on the untreated side, although not by a significant amount. CONCLUSIONS: The use of diathermy, according to the authors, is a non-invasive approach that may speed up the orthodontic alignment phase and reduce treatment duration, resulting in a lower risk of caries, gingival recessions, root resorptions, and patient compliance improvement, without side effects. Further studies and an adequate sample size will be needed to confirm the findings.

Effect of low-level laser therapy on the time needed for leveling and alignment of mandibular anterior crowding.

OBJECTIVES: To assess the effect of low-level laser therapy (LLLT) on overall leveling and alignment time of mandibular anterior crowding and associated pain after initial archwire placement. MATERIALS AND METHODS: Thirty-two females (18-25 years) with mandibular anterior crowding were randomly allocated into laser and control groups. Eligibility criteria included Angle Class I molar relationship and Little's irregularity index (LII) from 4 to 10 mm. Randomization was accomplished with a computer-generated random list. A 0.014-inch copper-nickel-titanium (Cu-NiTi) wire was inserted immediately after bonding of 0.022-inch Roth brackets followed by 0.016-inch Cu-NiTi, 0.016 × 0.022-inch NiTi then 0.017 × 0.025-inch stainless steel wire after completion of alignment. In-Ga-As laser was applied to the mandibular anterior segment in the laser group on days 3, 7, and 14, then at 1 month followed by every 2 weeks until completion of leveling and alignment. Visual analogue scale questionnaires were completed by each patient over 7 days from initial archwire placement. Digital models were used to monitor changes in the irregularity index. Blinding was applicable for outcome assessors only. RESULTS: The mean time for leveling and alignment was significantly lower in the laser compared to the control group (68.2 ± 28.7 and 109.5 ± 34.7 days, respectively). The laser group displayed a significantly higher mean alignment improvement percentage as well as lower pain scores compared to the control group. CONCLUSIONS: Within the constraints of the current study, LLLT has a potential for acceleration of anterior segment alignment as well as reduction of the pain associated with placement of initial archwires.

Efficacy of pulsed electromagnetic field in reducing treatment time: A clinical investigation.

INTRODUCTION: The long duration of orthodontic treatment is a major concern for the patient. This study aimed to evaluate the efficacy of pulsed electromagnetic field therapy (PEMF) in accelerating the orthodontic tooth movement, thus reducing treatment duration. METHODS: Nineteen patients requiring extraction of first premolars were selected for this study. The study design was randomly assigned (sealed envelope randomization) split-mouth design. The rate of individual canine retraction by a nickel-titanium closed-coil spring was done. The experimental side received a PEMF generated by a circuit powered by a watch battery. The circuit was embedded in a removable appliance. Foil was used to obstruct the control side from PEMF exposure. Patients were instructed to wear the appliance for 8-10 hours. Appliance with the device was given from the commencement of canine retraction until the canine retraction of one side was complete. Tooth movement was measured on progress models. RESULTS: An average increase of 31% in the rate of tooth movement was observed with the PEMF. CONCLUSIONS: PEMF is a good option to reduce orthodontic treatment duration.

Low-level laser therapy effectiveness in reducing initial orthodontic archwire placement pain in premolars extraction cases: a single-blind, placebo-controlled, randomized clinical trial.

BACKGROUND: The objective of this randomized clinical trial was to evaluate Low-Level Laser Therapy (LLLT) effectiveness in spontaneous and chewing pain reduction following initial orthodontic archwire placement. METHODS: 26 patients (mean age 20.07 ± 3.13 years) with maxillary Little's Irregularity Index (LII) of 7 mm or more that indicates first maxillary premolars extraction and no medications intake were eligible for this trial. Patients were randomly assigned with 1:1 ratio using simple randomization technique to receive either LLL or placebo treatment. Blinding was applicable for patients only. In the laser group, patients received a single LLL dose (wavelength 830 nm, energy 2 J/point) in four points (2 buccal, 2 palatal) for each maxillary anterior tooth root. Patients in the placebo group had the same laser application procedure without emitting the laser beam. Patients were asked to score spontaneous and chewing pain intensity by filling out a questionnaire with a 100-mm Visual Analogue Scale (VAS) after 1, 6, 24, 48, and 72 h of treatment application. Independent t-test was used to compare the mean pain scores between the laser and placebo groups for both spontaneous and chewing pain at each studied time point. RESULTS: No dropout occurred so the results of the 26 patients were statistically analyzed. Despite some clinical differences observed between the two groups, no statistical significance was found for each studied time point (p > 0.05) for both spontaneous and chewing pain except after 72 h for chewing pain with a VAS score of (18.84 ± 13.44) mm for the laser group compared to (38.15 ± 27.06) mm for the placebo group. CONCLUSIONS: LLLT, with the suggested parameters, is not effective in pain reduction following initial orthodontic archwire placement. TRIAL REGISTRATION: Name of the registry: Clinicaltrials.gov Trial registration number: NCT02568436. Date of registration: 26 September 2015 'Retrospectively registered'.

Comparison of rate of orthodontic tooth movement in adolescent patients undergoing treatment by first bicuspid extraction and en-mass retraction, associated with low level laser therapy in passive self-ligating and conventional brackets: A randomized controlled trial.

BACKGROUND: Low Level Laser Therapy (LLLT) is one of the various interventions to accelerate the rate of Orthodontic Tooth Movement (OTM) in adolescent patients who are undergoing en-mass retraction after all first bicuspid extractions. OBJECTIVES: To assess the efficacy of LLLT in increasing the rate of OTM. MATERIALS AND METHODS: Setting and sample population: Institutional Department of Orthodontics and Dentofacial Orthopaedics. Participants, study design and methods: 65 Patients requiring all first premolar extractions were randomly allocated to three groups. Two groups (Comprising of passive self-ligating brackets and conventional brackets) were treated with LLLT and one group served as the control (conventional brackets). The allocation ratio was 1:1:1.32. Eligibility criteria: adolescent patients with sound and healthy permanent dentition with Little's Irregularity Index<5mm. MAIN OUTCOME: rate of tooth movement in mm/month. Randomization and blinding: computer-generated random allocation sequence; only the data analyser was blinded by coding the digital models. Patients were reviewed once every month till the completion of space closure. STATISTICS: data normality was checked using Shapiro-Wilks test and Q-Q Plot. Parametric tests were applied for the inferential statistics (ANCOVA) with Dunnett's t test being used for post hoc analysis. RESULTS: There was a statistically significant enhancement in the rate of OTM in the 2 experimental groups (0.68/0.67mm/month in the right and left side of the maxilla and 0.66/0.65mm/month in the right and left side of the mandible) when compared with the control group (0.48mm/month in the maxilla and 0.48mm/month in the mandible) (P<0.05), but when the 2 experimental groups were compared no difference was observed (P>0.05). No serious harms were reported. CONCLUSION: A significant increase in the rate of OTM was observed with the application of LLLT. No difference was observed in the rate of OTM when comparing different ligation methods treated with LLLT. REGISTRATION: National Trial Registry (CTRI No- CTRI/2018/04/013156). Protocol was not published before trial commencement.

The effects of a clinically feasible application of low-level laser therapy on the rate of orthodontic tooth movement: A triple-blind, split-mouth, randomized controlled trial.

INTRODUCTION: This split-mouth trial aimed to investigate the effect of low-level laser therapy (LLLT) on the amount of maxillary canine distalization when applied every 4 weeks over 12 weeks. METHODS: Twenty-two adolescents and young adults (15 female, 7 male; aged 13-25 years; n = 22) requiring bilateral maxillary first premolar extractions were recruited. After extractions and leveling-alignment, canines were retracted using closed-coil nickel-titanium springs delivering 150 g of force. LLLT was applied to 8 intraoral points on the buccal and palatal sides around the canine root for 10 seconds per point, on day 0, 28, and 56 with the control side receiving sham application. Alginate impressions were taken every 4 weeks on day 0, 28, 56, and 84. The amount of tooth movement, anchorage loss, and canine rotation were measured digitally. Randomization was generated using www.randomisation.com and allocation concealment through sequentially numbered, opaque, sealed envelopes. Participants, operator, and statistic assessor were blinded. Linear regression modeling accounting for clustering within each patient was used to identify differences between LLLT and control sides. RESULTS: Twenty-one patients completed the study. The total amount of tooth movement was similar in the LLLT (2.55 ± 0.73 mm) and control group (2.30 ± 0.86 mm), whereas 0.25 mm (95% confidence interval, -0.21, 0.71 mm) of difference was insignificant (P = 0.27). No significant differences were found for anchorage loss (P = 0.22) or canine rotation (P = 0.25). No harms were reported. CONCLUSIONS: Application of LLLT every 4 weeks did not result in differences in the amount of tooth movement, anchorage loss, and canine rotation during extraction space closure.

Effects of low-level laser therapy and mechanical vibration on orthodontic pain caused by initial archwire.

INTRODUCTION: The aim of this study was to evaluate the effects of mechanical vibration and low-level laser therapy on orthodontic pain after placement of the initial archwire. METHODS: Sixty subjects with 3-6 mm maxillary dental crowding, a nonextraction fixed treatment plan, and no medical history were included in this study. The subjects were randomly divided into 3 groups, equally distributed by sex. In each subject, preadjusted edgewise appliances were placed in the maxillary arch from the left first molar to the right first molar, and a 0.014-inch round nickel-titanium archwire was fully engaged with elastomeric ties and cut at the end of first molar bondable tube. In group 1 (mean age 13.98 ± 2.68 y), mechanical vibration was performed 3 times: immediately, 24 hours, and 48 hours after engagement of the initial archwire. In group 2 (mean age 14.86 ± 2.06 y), low-level laser therapy was applied once: immediately after the insertion of the initial archwire. Group 3 (mean age 14.41 ± 1.78 y) served as the control group. Pain scores were determined with the use of a visual analog scale (VAS). RESULTS: Although no statistically significant differences were found among the groups (P >0.05), the mean VAS scores for the mechanical vibration group were consistently lower than those of the control and low-level laser therapy groups at all measured time points. CONCLUSIONS: The mechanical vibration group had lower, though nonsignificant, VAS scores for all measured time points. Additional clinical trials are recommended for more definitive conclusions.

Is Low-Level Laser Therapy an Effective Method to Alleviate Pain Induced by Active Orthodontic Alignment Archwire? A Randomized Clinical Trial.

OBJECTIVE: The aim of this study is to assess if low-level laser therapy (LLLT) alleviates pain after the placement of orthodontic alignment archwire and if there could be a specific indication for the usage of LLLT according to the amount of dental crowding. MATERIALS AND METHODS: Ninety subjects were included and randomly assigned to the tested group (orthodontic treatment and LLLT), placebo group (orthodontic treatment and simulated LLLT), and control group (orthodontic treatment only). Inclusion criteria are age between 13 and 30 years, completely erupted mandibular teeth, and lower crowding of ≥3 mm. Exclusion criteria are spaces or diastema in the lower arch, ectopic teeth, treatment plan including extractions or the use of auxiliary devices, and previous orthodontic treatment. Patients reported the pain experienced by using a numeric rating scale, ranging from 0 to 10, at specific time intervals, that is, 2 hours, 6 hours, 24 hours, and from day 2 to 7. Kruskal-Wallis H Test was used to assess differences in the maximum pain and pain experienced at each time interval among the three groups and in the maximum pain reported among subjects with different degree of crowding. RESULTS: The final sample consisted of 84 patients, 41 male and 43 female patients, with a mean age of 16.5 ± 2.8 years. The pain experienced at each time interval and the maximum pain score were significantly lower in the tested group, whereas no differences were found between control and placebo groups. Moreover, no differences were found in the pain experienced among subjects with mild, moderate, and severe incisor crowding in all groups. CONCLUSIONS: LLLT is effective in alleviating the intensity and duration of pain experienced by patients after the engagement of alignment archwire. However, there is no specific indication for the usage of LLLT according to the amount of crowding.

[Effect of single low level laser therapy on initial pain during fixed orthodontic treatment].

PURPOSE: To investigate the effect of single low level laser therapy on initial pain during fixed orthodontic treatment. METHODS: Sixty patients who underwent fixed orthodontic treatment in our hospital from January 2015 to December 2017 were enrolled.Patients were divided into 2 groups by random number table method, 30 in each group. Patients in the experimental group were treated with a single low level laser therapy ,while patients in the control group were treated with a placebo.The results of the 2 groups were compared in regard to spontaneous pain and chewing pain during the day and night using SPSS 22.0 software package. RESULTS: Spontaneous pain during day and night with 0.012, 0.014 inch superelastic nickel-titanium (NiTi) line was significantly lower in the experimental group than in the control group(P<0.05), and there was no significant difference with 0.016 and 0.018 inch NiTi (P>0.05).Chewing pain with 0.012, 0.014, 0.016, and 0.018 inch NiTi lines in the experimental group was significantly lower than that in the control group(P<0.05). CONCLUSIONS: Single low level laser therapy significantly reduced postoperative pain while placing a superelastic NiTi wire for initial alignment and correction.

Physical properties of root cementum: Part 27. Effect of low-level laser therapy on the repair of orthodontically induced inflammatory root resorption: A double-blind, split-mouth, randomized controlled clinical trial.

INTRODUCTION: The purpose of this 2-arm-parallel split-mouth trial was to investigate the effect of low-level laser therapy (LLLT) on the repair of orthodontically induced inflammatory root resorption (OIIRR). METHODS: Twenty patients were included in this study, with 1 side randomly assigned to receive LLLT, and the other side served as a sham. Eligibility criteria included need for bilateral maxillary first premolar extractions as part of fixed appliance treatment. OIIRR was generated by applying 150 g of buccal tipping force on the maxillary first premolars for 4 weeks. After the active force was removed, the teeth were retained for 6 weeks. LLLT commenced with weekly laser applications using a continuous beam 660-nm, 75-mW aluminum-gallium-indium-phosphorus laser with 1/e2 spot size of 0.260 cm2, power density of 0.245 W/cm2, and fluence of 3.6 J/cm2. Contact application was used at 8 points buccally and palatally above the mucosa over each tooth root for 15 seconds with a total treatment time of 2 minutes. After 6 weeks, the maxillary first premolars were extracted and scanned with microcomputed tomography for primary outcome OIIRR calculations. Subgroup analysis included assessment per root surface, per vertical third, and sites of heaviest compressive forces (buccal-cervical and palato-apical). Randomization was generated using www.randomization.com, and allocation was concealed in sequentially numbered, opaque, sealed envelopes. Blinding was used for treatment and outcome assessments. Two-tailed paired t tests were used to determine whether there were any statistically significant differences in total crater volumes of the laser vs the sham treated teeth. RESULTS: Total crater volumes were 0.746 mm3 for the laser treated teeth and 0.779 mm3 for the sham. There was a mean difference of 0.033 ± 0.39 mm3 (95% CI, -0.21 to 0.148 mm3) greater resorption crater volume in the sham group compared with the laser group; this was not statistically significant (P = 0.705). No harm was observed. CONCLUSIONS: No significant difference was found between LLLT and sham control groups in OIIRR repair.

The Efficacy of Low-level Laser Therapy on Pain caused by Placement of the First Orthodontic Archwire: A Clinical Study.

Aim: This study was conducted to clinically evaluate the effect of low-level laser therapy (LLLT) as a method of reducing pain reported by patients after placement of their first orthodontic archwires. Materials and methods: A sample of 10 patients with an age group of 12 to 26 years with moderate-to-severe anterior crowding was selected. Each patient was assigned to an experimental group (left quadrant with laser therapy) and a control group (right quadrant with no laser therapy). Low-level laser therapy was given immediately after the placement of initial archwire. All patients were instructed to fill up a survey form at home over the next 7 days. Results: The results revealed that the average onset of pain in the experimental group (16.10 hours) was significantly reduced when compared with the control group (3.10 hours). The most painful day was similar for both the groups. The pain ceased much sooner in the experimental group than in the control group. The intensity of pain was lesser in the experimental group when compared with the control group. Conclusion: Low-level laser therapy was an effective and noninvasive method for controlling pain in orthodontic patients after receiving their first archwires. The duration and intensity of pain reduced with the application of LLLT Clinical significance: Pain reduction during orthodontic procedures. Keywords: Low-level laser therapy, Nickel-titanium wires, Orthodontic pain.

Effectiveness of pulsed electromagnetic field for pain caused by placement of initial orthodontic wire in female orthodontic patients: A preliminary single-blind randomized clinical trial.

INTRODUCTION: The purpose of this 2-arm parallel trial was to assess the effects of pulsed electromagnetic field (PEMF) on the reduction of pain caused by initial orthodontic tooth movement. METHODS: Thirty-three female patients (mean age, 16.8 ± 3.8 years) who began orthodontic treatment using fixed appliances were examined. In the pilot study, male patients were less likely to use the PEMF device (epatchQ; Speed Dental, Seoul, Korea) and answer a survey consistently, so eligibility criteria were female patients who were periodontally and systemically healthy at the initiation of treatment and had no history of dental pain in the prior 2 weeks or who used no medications (anti-inflammatory or analgesic drugs) during the experiment period. Each patient had brackets bonded on the maxillary teeth, and a 0.014-in nickel-titanium archwire was tied with elastomeric rings. Their maxillary arches were randomly divided into left and right sides in a split-mouth design: a normal PEMF device (experimental group) was used on 1 side, and a PEMF device with an inversely inserted battery (placebo group) was used on the opposite side of the arch for 7 hours on 3 consecutive nights. A Google survey link was sent to the patients' mobile phones via text message, and they were instructed to record their current pain on the survey. The survey was sent a total of 6 times after insertion of the initial archwire at 0 (T0), 2 (T1), 6 (T2), 24 (T3), 48 (T4), and 72 (T5) hours. Patients recorded the degree of pain in resting and clenching states using a numeric rating scale (NRS) from 1 (no pain) to 10 (worst pain). PEMF devices were used after T2. Generalized linear mixed models, along with ancillary pairwise analyses, were used to model and evaluate the differences in pain reported over 72 hours. RESULTS: The NRS scores did not differ across the groups during the before-PEMF phase for resting (mean difference, -0.07; 95% confidence interval [CI], -0.73 to 0.59; P = 0.842) and clenching (mean difference, -0.28; 95% CI, -1.11 to 0.56, P = 0.513). During the after-PEMF phase, NRS scores in the experimental group were significantly lower than those in the placebo group during both resting (mean difference, -1.46; 95% CI, -2.06 to -0.85; P = <0.001) and clenching (mean difference, -1.88; 95% CI, -2.74 to -1.02, P = <0.001). The NRS scores did not differ across the groups during the before-PEMF phase for either state but were significantly lower in the experimental group than in the placebo group at T3, T4, and T5 (P <0.01). The average NRS score in the clenching state was significantly greater than in the resting state. CONCLUSIONS: PEMF was effective in reducing orthodontic pain caused by initial archwire placement. REGISTRATION: The trial was not registered. PROTOCOL: The protocol was not published before trial commencement.

Measurement of forces and moments around the maxillary arch for treatment of a simulated lingual incisor and high canine malocclusion using straight and mushroom archwires in fixed lingual appliances.

INTRODUCTION: An Orthodontic SIMulator (OSIM) was used to investigate the propagation of forces and moments around a simulated archform for a gingival displaced canine and lingual displaced lateral incisor using fixed lingual orthodontic appliances. METHODS: In-Ovation L self-ligating lingual brackets were bonded to anatomically shaped teeth on the OSIM, and the teeth were positioned such that a G4 NiTi 0.016" large maxillary mushroom archwire could be ligated in passive position. Each trial consisted of two movements: a 3mm lingual displacement of the 1-2 lateral incisor at 0.2 mm increments, and a 1.5 mm gingival displacement of the 2-3 canine at 0.15 mm increments (n = 50). Anterior brackets were repositioned to accommodate G4 NiTi 0.016" universal straight archwires (n = 50). Tests were completed at 37°C, and force and moment data in all directions was collected for each tooth around the arch at all increments. RESULTS: In general, the straight archwire produced significantly larger forces and moments at the centre of resistance for teeth of interest than did mushroom archwires. Specifically, the straight archwire produced 2.62 N and 3.81 N more force in the direction of tooth movement on the tooth being moved for a gingival displaced canine and lingual displaced lateral incisor, respectively, as compared to mushroom archwires. CONCLUSIONS: Results from this study suggest that mushroom archwires may provide better mechanics for movement of teeth in the anterior segment when using a round archwire; however, only biomechanical data was considered in this study and there are many factors that need to be considered in treatment planning.

Decrowding of lower anterior segment with and without photobiomodulation: a single center, randomized clinical trial.

The aim of this study was to evaluate the effect of low-level light therapy using light-emitting diodes (LEDs) on the speed of tooth movements that were required for the leveling and aligning of the lower anterior segment during non-extraction orthodontic treatment. The sample was comprised of patients (n = 40) with lower anterior crowding who were treated with self-ligating orthodontic brackets and a standardized wire sequence. A test group of patients (n = 20) who were treated with extraoral infrared light therapy for 20 min daily with at least 80 % compliance was compared to a control group (n = 20). The date of the first arch wire placement was recorded as T1, and the date of the completion of the lower anterior segment decrowding was recorded as T2. A final impression was also taken at T2. The time between T1 and T2 was significantly reduced by 22 % in the test group compared to the control group (68.3 vs. 87.8 days, respectively, p < 0.043). The use of photobiomodulation for 20 min daily at a wavelength of 850 nm might reduce the time required to resolve lower anterior crowding. This trial and its protocol were not registered on a publicly accessible registry.

Torsional strength of computer-aided design/computer-aided manufacturing-fabricated esthetic orthodontic brackets.

OBJECTIVE: To fabricate orthodontic brackets from esthetic materials and determine their fracture resistance during archwire torsion. MATERIALS AND METHODS: Computer-aided design/computer-aided manufacturing technology (Cerec inLab, Sirona) was used to mill brackets with a 0.018 × 0.025-inch slot. Materials used were Paradigm MZ100 and Lava Ultimate resin composite (3M ESPE), Mark II feldspathic porcelain (Vita Zahnfabrik), and In-Ceram YZ zirconia (Vita Zahnfabrik). Ten brackets of each material were subjected to torque by a 0.018 × 0.025-inch stainless steel archwire (G&H) using a specially designed apparatus. The average moments and degrees of torsion necessary to fracture the brackets were determined and compared with those of commercially available alumina brackets, Mystique MB (Dentsply GAC). RESULTS: The YZ brackets were statistically significantly stronger than any other tested material in their resistance to torsion (P < .05). The mean torques at failure ranged from 3467 g.mm for Mark II to 11,902 g.mm for YZ. The mean torsion angles at failure ranged from 15.3° to 40.9°. CONCLUSION: Zirconia had the highest torsional strength among the tested esthetic brackets. Resistance of MZ100 and Lava Ultimate composite resin brackets to archwire torsion was comparable to commercially available alumina ceramic brackets.

Does stinging nettle (Urtica dioica) have an effect on bone formation in the expanded inter-premaxillary suture?

OBJECTIVE: To determine whether systemically given stinging nettle (SN) has an effect on bone formation in response to expansion of the rat inter-premaxillary suture. MATERIALS AND METHODS: A total of 28 male Wistar albino rats were randomly divided into 4 equal groups: control (C), only expansion (OE), SN extract given only during the expansion and retention periods (SN group; a total of 17days), and SN extract given during the nursery phase before expansion (a period of 40days) and during the expansion and retention periods (N+SN group; a total of 57days). After the 5-day expansion period was completed, the rats in the OE, SN, and N+SN groups underwent 12days of mechanical retention, after which they were sacrificed, and their premaxilla were dissected and fixed. A histologic evaluation was done to determine the number of osteoblasts, osteoclasts, and capillaries, as well as the number and intensity of inflammatory cells and new bone formation. RESULTS: Statistically significant differences were found between the groups in all histologic parameters except the ratio of intensities of inflammatory cells. New bone formation and the number of capillaries were significantly higher in the SN groups than in the other groups. The statistical analysis also showed that the numbers of osteoblasts, osteoclasts, and capillaries were highest in the N+SN group. CONCLUSION: Systemic administration of SN may be effective in accelerating new bone formation and reducing inflammation in the maxillary expansion procedure. It may also be beneficial in preventing relapse after the expansion procedure.

Influence of bio-lubricants on the orthodontic friction.

The Friction force of Stainless Steel (SS) and Nickel-Titanium (Ni-Ti) rectangular archwires against stainless steel brackets was investigated. Two types of brackets were used namely: Self-ligating brackets (SLB) and conventional brackets (CB). The friction tests were conducted on an adequate developed device under dry and lubricated conditions. Human saliva, olive oil, Aloe Vera oil, sesame oil and sunflower oil were used as bio-lubricants. The friction force was examined as a function of the ligation method and oil temperature. It is found that under oil lubrication, the friction behavior in the archwire/bracket assembly were the best. The SLB ligation was better than the conventional ligation system. The enhancement of the frictional behavior with natural oils was linked to their main components: fatty acids.

Intraoral photobiomodulation-induced orthodontic tooth alignment: a preliminary study.

BACKGROUND: Numerous strategies have been proposed to decrease orthodontic treatment time. Photobiomodulation (PBM) has previously been demonstrated to assist in this objective. The aim of this study was to test if intraoral PBM increases the rate of tooth alignment and reduces the time required to resolve anterior dental crowding. METHODS: Nineteen orthodontic subjects with Class I or Class II malocclusion and Little's Irregularity Index (LII) ≥ 3 mm were selected from a pool of applicants, providing 28 total arches. No cases required extraction. The test group (N = 11, 18 arches, 10 upper, 8 lower) received daily PBM treatment with an intraoral LED device (OrthoPulse™, Biolux Research Ltd.) during orthodontic treatment, while the control group (N = 8, 10 arches, 3 upper, 7 lower) received only orthodontic treatment. The PBM device exposed the buccal side of the gums to near-infrared light with a continuous 850-nm wavelength, generating an average daily energy density of 9.5 J/cm(2). LII was measured at the start (T0) of orthodontic treatment until alignment was reached (T1, where LII ≤ 1 mm). The control group was mostly bonded with 0.018-in slot self-ligating SPEED brackets (Hespeler Orthodontics, Cambridge, ON. Canada), while conventionally-ligating Ormco Mini-Diamond twins were used on the PBM group (Ormco, Glendora, Calif. USA). Both groups progressed through alignment with NiTi arch-wires from 0.014-in through to 0.018-in (Ormco), with identical arch-wire changes. The rate of anterior alignment, in LII mm/week, and total treatment time was collected for both groups. Cox proportional hazards models were used to compare groups and while considering age, sex, ethnicity, arch and degree of crowding. RESULTS: The mean alignment rate for the PBM group was significantly higher than that of the control group, with an LII change rate of 1.27 mm/week (SD 0.53, 95 % CI ± 0.26) versus 0.44 mm/week (SD 0.20, 95 % CI ± 0.12), respectively (p = 0.0002). The treatment time to alignment was significantly smaller for the PBM group, which achieved alignment in 48 days (SD 39, 95 % CI ± 39), while the control group took 104 days (SD 55, 95 % CI ±19, p = 0.0053) on average. These results demonstrated that intraoral PBM increased the average rate of tooth movement by 2.9-fold, resulting in a 54 % average decrease in alignment duration versus control. The average PBM compliance to daily treatments was 93 % during alignment. CONCLUSIONS: Under the limitations of this study, the findings suggest that intraoral PBM could be used to decrease anterior alignment treatment time, which could consequently decrease full orthodontic treatment time. However, due to its limitations, further research in the form of a large, randomized trial is needed. TRIAL REGISTRATION: ClinicalTrials.gov NCT02267837 . Registered 10 October 2014.

Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.

BACKGROUND: Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before. METHODS: This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, ß > 0.99). This trial was not registered. It was self-funded by the authors. RESULTS: Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001). CONCLUSIONS: Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.