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Background and Objective: Correction of vertical maxillary excess (VME) via superior surgical repositioning of the maxilla can lead to counterclockwise rotation of the mandible along with alteration of jaw relationship and dental occlusion. The aim of this study was to determine the interrelationship between surgical superior repositioning of the maxilla and lower incisors inclination change after mandibular autorotation. Methods: In this correlational study, 13 patients with Class II malocclusion, mandibular plane angle greater than 27 degrees, and fully-erupted lower second molars were examined. Superior maxillary repositioning of 4mm was simulated on lateral cephalometric radiographs and maxillary dental models. Degree of mandibular autorotation was then predicted on lateral cephalograms, considering radiographic center of the condyle as the center of rotation, and on semi-adjustable articulator, measuring the articulator’s upper arm inclination change in degrees by digital inclinometer. As lower incisors rotate on the same arc of rotation as the mandible, measuring mandibular autorotation also indicates the amount of change in lower incisors’ inclination. Findings: Mean (standard deviation) values of mandibular autorotation and lower incisors’ inclination change after 4mm superior repositioning of the maxilla were 3.38±0.93 and 2.63±0.83 degrees based on Prediction Planning and Model Planning techniques, respectively. The difference between two methods was statistically significant (p

Background and Objective: Stability is one of the major issues in orthodontics. The purpose of this study is to investigate the effect of Low-Level Laser Therapy on the rate of relapse of mandibular incisors. Methods: This Single-blinded Randomized Controlled Trial consisted of twenty patients (aged 12-18 years) seeking orthodontic treatment. The subjects were divided into two groups with randomly permuted blocks (n=10): experimental and control groups. The Little’s irregularity index was measured on plaster models prior to treatment using American Board of Orthodontic Measuring Gauge. After unraveling of initial crowding, archwires on mandibular anterior segments of both groups were removed. The experimental group received Low-Level Diode Laser at 808 nm wavelength, 250 mW power, 4J energy and continuous wave mode, on coronal third of lower central and lateral incisors and canines’ roots for sixteen seconds three times a week, within a four-week period. The relapse rate was quantified on each plaster model using Little’s irregularity index at the end of first (T1), second (T2), third (T3), and fourth (T4) weeks. Findings: The study population consisted of twenty patients aged 12-18 years who had 5-9 mm crowding and proper oral hygiene. At T1, the relapse rate was 0 mm and 0.05±0.15 mm in experimental and control group, respectively, which was not statistically significant (p=0.343). Over the following weeks, however, there was statistically significant difference between the relapse rate of the two groups (p=0.003). The mean rate of relapse percentage was 4.48±4.31 mm in experimental and 12.06±5.52 mm in control group, which was significantly lower in Low-Level Laser Therapy group. Conclusion: The application of Low-Level Laser Therapy at 808 nm wavelength on mandibular incisors during orthodontic retention phase may slow down the relapse rate. Therefore, it could be considered as an effective adjunct to reduce immediate relapse.

BACKGROUND AND OBJECTIVE: Proportional relationship between different facial structures, including soft tissue thickness and dental and skeletal components, is the key to beauty. Today facial soft tissue harmony is the primary goal of orthodontic treatment, unlike the past which focused only on hard tissue and dental occlusion. The aim of this study was to measure facial soft tissue thickness in the northern population of Iran with class I skeletal pattern in lateral cephalometry and compare these values between males and females to use the results in orthodontic treatment and craniofacial reconstructions. METHODS: In this cross-sectional research, 180 lateral cephalometry of 77 male and 103 female, aged between 18-24 years who had referred to private orthodontic offices, were traced on acetate paper. Then, 10 anatomical variables were measured in Glabella, Nasion, Rhinion, Subnasal, Upper lip, Stomion, Lower lip, Labiomental region, Pogonion and Menton parallel to the Frankfurt plan. FINDINGS: Facial soft tissue thickness in males was significantly higher than females in Nasion (male=5.65±1.55, female=4.38±1.47), Rhinion (male=3.07±0.64, female=2.5±0.57), Subnasal (male=16.39±2.55, female=14.05±1.44), Upper lip (male=15.51±2.29, female=13.57±1.64), Lower lip (male=16.48±1.85, female=14.64±1.39), Labiomental (male=11.02±1.46, female=10.49±1.67) and Pogonion (male=11.4±1.64, female=10.32±1.77) (p

BACKGROUND AND OBJECTIVE: Mechanical stress alters the secretory proteins concentration at the local level in bone and the oral cavity. Recognition of these proteins and their roles in teeth movement or tissue destruction diagnosis is very important. The aim of this study was to evaluate the changes of total protein concentration in whole saliva (WS) before and after orthodontic tooth movement.METHODS: This experimental study was done on 40 adolescent and young patients who were in need of orthodontic treatment for both jaws. Samples of W.S. were collected once before the placement of orthodontic separators, and 1 day and 1 week after the placement of orthodontic separators. Total protein concentration was measured by spectrophotometric method.FINDINGS: Total protein concentration before the placement of orthodontic separators, 1 day and 1 week after were 127.3, 135.1, 131.6 (mg/dl). Total protein concentration elevated after initial tooth movement (one day after the placement of orthodontic separators) and then, tended to the pretreatment levels at the 7th day, but it didn’t exactly return to it (p

Background and Objective: Due to increasing of child and youth patients that require orthodontic treatment procedures, finding the person with normal occlusion and cephalometric analysis can be valuable. The aim of this study was to investigate the indicators and cephalometric parameters of Babol youths with normal occlusion. Methods: In this analytical and cross-sectional study, 34 male students between 12-18 years with mean age of 15 and with CLI connection, suitable overjet and overbite, without crowding and spacing and suitable profile were selected among 1200 students of Babol. After taking their parents consent, lateral cephalometry from them was performed in similar condition. After necessary analyses (Down, Tweed and Steiner), they were compared with Caucasian race patterns. Findings: After tracing and cephalometric analysis of each sample, these findings were obtained totally: Facial plane angle 82.41°, angle of convexity 4.78°, A-B plane to N-pog -4.67°, mandibular plane to Frankfort (FMA) 28.06°, y-axis to Frankfort 65.50°, occlusal plane to Frankfort 12.60°, interincisal angle 124.74°, lower incisor to occlusal plane 25.66°, lower incisor to mandibular plane (IMPA) 100.69°, lower incisor to Frankfort (FMIA) 51.89°, lower incisor to mandibular plane (Tweed analysis) 100.69°, SNA 80.63°, SNB 77.93°, ANB 2.71°, mandibular plane to SN 31.97°, occlusal plane to SN 16.81°, upper incisor to N-A 22.82°, lower incisor to NB 30.44°, upper incisor to AP 8.53mm, upper incisor to NA 7mm, lower incisor to NB 7.13mm. Conclusion: According to the results, facial and interincisal angle compared to white European race samples had lower average. But, angle of convexity, FMA, y-axis and occlusal plane to Frankfort angle, lower incisor to occlusal plane angle, IMPA, lower incisor to NB angle, lower incisor to NB (mm) were higher while angles of AB to N-pog, SNA, SNB, ANB, mandibular plane to SN, occlusal plane to SN, upper incisor to NB (mm), do not show considerable difference with white race in this study.

Background and Objective: One of the dentoalveolar abnormalities is class III malocclusion with maxillary deficiency. Correction of this malocclusion in growth ages using orthopedic appliances to avoid further extensive surgical treatment and improvement in soft tissue profile will help to reach beauty. The objective of this study was to survey changes in soft tissue profile following tongue guard in class III patients with maxillary deficiency. Methods: In this experimental study, 20 class III patients (4 males and 16 females) with maxillary deficiency and reserve overjet with mean age of 7.5 years old referring to orthodontic department of Babol dental school in the year 2000 were treated by tongue guard at least for 6 months. 2 lateral cephalometry were obtained before and after treatment for each patient and after tracing results were compared. Findings: After cephalometric analyzing and comparison between before and after tracing, an obvious increase was found in forward movement of subnasal soft tissue (3.59mm), superior labial sulcus (3.12mm), incisal edge of centrals (3.38mm), upper lip prominence (4.53mm). Lower lip prominence (1.05mm), inferior labial sulcus (1.47 mm) and the most anterior point of chin (1.56mm) move anteriorly to some extent. Vertical distance of subnasal soft tissue (2.03 mm), superior labial sulcus (2.22mm), upper lip prominence (2.65mm), inferior labial sulcus (3.41mm), the most prominent point of chin (2.59mm) and incisal edge (3.47mm) have increased significantly. Nasolabial angle (-1.44°), mentolabial angle (1.82°) and soft tissue convexity angle (-2.36°) have decreased. Upper lip thickness decreased. Distance between upper lip and esthetic line decreased and distance between lower lip and E-line increased. Conclusion: Due to results of our study in class III patients with maxillary deficiency treated by tongue guard because of change in position of inferior hard tissue and teeth. We can expect an improvement in soft tissue profile due to movement of mid third of face forwardly and downward and backward rotation of mandible.

Background and Objective: Determination of the relation between periphery of dental arch and teeth size which mostly done before eruption of some permanent teeth, is of important levels of diagnosis in mixed dentition. Determination of this relationship is not possible without prediction and distinct evaluation of unerupted permanent mesiodistal width (Permanent canines and premolars). The aim of this study was to evaluate the required space for eruption of canine and premolars using total width of lower incisor in Iranian people by Tanaka & Johnston method. Methods: In this study mesiodistal width of permanent first and second premolar and canine in each quadrant also of 4 lower incisors were measured in 604 dental casts of under 20 year old people (In Mazandaran) using Koulis with accuracy of 0.02 millimeter and final measurements were illustrated in a table. Needed teeth for measurement were completely erupted, caries free and without fracture or restoration. Findings: The mean of mesiodistal width of lower incisors, total mesiodistal width of upper and lower canine and premolars and a and b indexes for Tanaka and Johnston equation (Y=aX+b), a=0.167, b=19.387 for mandible and a=0.195, b=18.723 for maxilla have been calculated. Meanwhile X is the sum of lower incisor mesiodistal width and Y is the sum of canine and premolar mesiodistal width in one side. Conclusion: In present study, equation of Tanaka and Johnston is recommended. So its dependence on race is obvious.

Objective: The current study aimed to identify and analyze missense single nucleotide polymorphisms (SNPs) that can potentially cause mandibular prognathism., Methods: After reviewing the articles, 56 genes associated with mandibular prognathism were identified and their missense SNPs were retrieved from the NCBI website. Several web-based tools including CADD, PolyPhen-2, PROVEAN, SNAP2, PANTHER, FATHMM, and PON-P2 were used to filter out harmful SNPs. Additionally, ConSurf determined the level of evolutionary conservation at positions where SNPs occur. I-Mutant2 and MUpro predicted the effect of SNPs on protein stability. Furthermore, to investigate the structural and functional changes of proteins, HOPE and LOMETS tools were utilized., Results: Based on predictions in at least four web-based tools, the results indicated that PLXNA2-rs4844658 , DUSP6-rs2279574 , and FBN3-rs33967815 are harmful. These SNPs are located at positions with variable or average conservation and have the potential to reduce the stability of their respective proteins. Moreover, they may impair protein activity by causing structural and functional changes., Conclusions: In this study, we identified PLXNA2-rs4844658 , DUSP6-rs2279574 , and FBN3-rs33967815 as potential risk factors for mandibular prognathism using several web-based tools. According to the possible roles of PLXNA2, DUSP6, and FBN3 proteins in ossification pathways, we recommend that these SNPs be investigated further in experimental research. Through such studies, we hope to gain a better understanding of the molecular mechanisms involved in mandible formation., (© 2023 Published by Elsevier B.V. on behalf of Craniofacial Research Foundation.)

Objective: The current study aimed to assess the association between collagen type II alpha 1 chain (COL2A1) single nucleotide polymorphism (SNP: rs2070739; C>T; G1405S) and mandibular skeletal malocclusions in the population of Mazandaran (North Iran)., Design: During 13 months, 102 control samples, 81 samples with skeletal Class III malocclusion contributed by mandibular prognathism and 82 samples with skeletal Class II malocclusion contributed by mandibular retrognathism were screened. Cephalometric analysis was performed to determine the type of abnormalities. COL2A1-G1405S genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The HOPE tool was used to investigate the effect of COL2A1-G1405S on the three-dimensional structure of protein., Results: Results showed that there is no significant correlation between genotypes and alleles related to COL2A1-G1405S and mandibular prognathism (CT genotype: p-value= 0.210; T allele: p-value= 0.222). On the other hand, an association was observed between COL2A1-G1405S and mandibular retrognathism (CT genotype: p-value= 0.008; T allele: p-value= 0.011). The outputs of the HOPE tool also showed that COL2A1-G1405S can disrupt the NC1 domain of the protein., Conclusions: Here, we provide evidence that COL2A1-G1405S polymorphism may have positive correlation with the risk of skeletal Class II malocclusion contributed by mandibular retrognathism in the population of Mazandaran. Given that the COL2A1-G1405S occurs in NC1 domain, it is possible that this domain plays an important role in signaling pathways related to ossification. So, we suggest that the study of COL2A1 SNPs can help researchers understand the significant role of this collagen in mandibular skeletal malocclusions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Collagens are the most abundant proteins in the extra cellular matrix/ECM of human tissues that are encoded by different genes. There are single nucleotide polymorphisms/SNPs which are considered as the most useful biomarkers for some disease diagnosis or prognosis. The aim of this study is screening and identifying the functional missense SNPs of human ECM-collagens and investigating their correlation with human abnormalities. All of the missense SNPs were retrieved from the NCBI SNP database and screened for a global frequency of more than 0.1. Seventy missense SNPs that met the screening criteria were characterized for functional and stability impact using six and three protein analysis tools, respectively. Next, HOPE and geneMANIA analysis tools were used to show the effect of SNPs on three-dimensional structure (3D) and physical interaction of proteins. Results showed that 13 missense SNPs (rs2070739, rs28381984, rs13424243, rs1800517, rs73868680, rs12488457, rs1353613, rs59021909, rs9830253, rs2228547, rs3753841, rs2855430, and rs970547), which are in nine different collagen genes, affect the structure and function of different collagen proteins. Among these polymorphisms, COL4A3-rs13424243 and COL6A6-rs59021909 were predicted as the most effective ones. On the other hand, designed mutated and native 3D of rs13424243 variant illustrated that it can disturb the protein motifs. Also, geneMANIA predicted that COL4A3 and COL6A6 are interacting with some proteins including: DDR1, COL6A1, COL11A2 and so on. Based on our findings, ECM-collagens functional SNPs are important and may be considered as a risk factor or molecular marker for human disorders in the future studies., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Long-term retention with fixed retainers with a high success rate seems to be a reasonable solution to minimize or prohibit relapse of orthodontic treatment., Methods: Two hundred sixty patients between 13 and 30 years old were recruited for this study. The 0.0175 stainless steel twisted wire (G&H Orthodontics, USA) was compared with a single-strand ribbon titanium lingual retainer wire (Retainium, Reliance orthodontics, USA) was used. When treatment was completed, the retainers were bonded from canine to canine in the mandibular arch of the participants. In the follow-up visits, the patients were recalled every 3 months during the 24 months. Detachments, the time of debonding, and side effects were recorded. Statistical analysis was performed by a blinded statistician using a statistical package for Social Science (SPSS, Version20). After descriptive statistics, Kaplan-Meier analysis was performed to measure the survival rates of each retainer. P value < 0.05 was considered as significant., Results: Finally, 138 patients who received twisted wire splint and 112 patients who received ribbon wire were included in the analysis. The average duration of success was about 23 months for twisted wire and ribbon wire, according to the Kaplan-Meier estimates. The analysis showed no significant overall difference between the treatments (p = 0.13). Failure rates in terms of detachments in all groups occurred at the enamel junction, and it was 25 in twisted retainer group (18.1%) and was 10 in ribbon retainer group (8.9%); the Kaplan-Meier analysis test detected a significant difference in the failure rates between the groups (p = 0/006)., Conclusions: Although the conventional twisted stainless steel wire and single-strand titanium flat metal ribbon wire as fixed orthodontic retainers have the same clinical effects, it was shown that the ribbon wire has less failure in terms of detachments.

Background: Orthodontic tooth movement (OTM) can be accelerated by increasing bone turnover. Carrageenan is a common food additive, which can induce inflammation. Hence, it might accelerate OTM. However, it has not been investigated to date., Methods: This 2-phase preliminary animal experimental study was conducted on 28 Wistar rats. A pilot study on 5 mice was done to estimate the experimental dose of carrageenan. The first phase evaluated the effect of a 40μL carrageenan 1% injection on inflammation status in 7 rats versus 7 control rats, 6hours after the injection. The second phase examined the effect of the same dose of carrageenan on OTM speed during 21 days of incisor retraction in rat, in two groups: control (normal saline) and carrageenan (n=7×2). This sample size was pre-determined based on a priori power calculations. In phase II, osteoclastic activity was also evaluated, 21 days after the injection. The groups were compared statistically (α=0.05)., Results: Six hours after carrageenan injection, 1, 3, and 3 rats had inflammation scores of 3 to 1, respectively. Six hours after saline injection, 1 rat had a score of 1 and the remainder had no inflammation (P=0.0023, Mann-Whitney). Twenty-one days after saline and carrageenan injection, OTMs were 0.7±0.3 and 1.1±0.4mm, respectively, (P=0.053, Mann-Whitney). Twenty-one days after saline and carrageenan injection, mean osteoclast counts were, respectively, 4.87±1.849 and 7.143±1.727 per field (P=0.025, Mann-Whitney)., Conclusion: Local injection of carrageenan can induce inflammation after 6hours. It can increase approximately 1.6-fold the speed of OTM, and increase the osteoclast count 1.5-fold after 21 days of space closure., (Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.)

Objective: This study aims at reducing frictional resistance of the ceramic brackets by using CO 2 laser irradiation., Methods: Forty-two polycrystalline Al 2 O 3 ceramic brackets were randomly divided into six groups of seven samples: a control group B0 (not subjected to laser irradiation) and five groups subjected to irradiation with intensities of 10 (B10), 30 (B30), 70 (B70), 90 (B90), and 110 (B110) J/cm 2 . After irradiation, two samples from each group were evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while the remaining five samples were tested for frictional resistance. The sliding friction of stainless steel wires (SS-wires) in the brackets was measured using a universal testing machine., Results: Samples from the first set (groups B0, B10, and B30) were significantly more resistant to wire sliding than the samples from the second set (groups B70, B90, and B110). The SEM analysis shows different degrees of blister formation on the bracket surfaces subjected to laser irradiation and no changes in their grain sizes. The AFM results indicate more consistent blister formation for groups B70, B90, and B110 than for other groups., Conclusion: Different CO 2 laser power intensities significantly affect frictional resistances of SS-wires in Al 2 O 3 ceramic brackets., (© 2017 Wiley Periodicals, Inc.)

Nano-silver and nano-titanium oxide films can be coated over brackets in order to reduce bacterial aggregation and friction. However, their antimicrobial efficacy, surface roughness, and frictional resistance are not assessed before. Fifty-five stainless-steel brackets were divided into 5 groups of 11 brackets each: uncoated brackets, brackets coated with 60 µm silver, 100 µm silver, 60 µm titanium, and 100 µm titanium. Coating was performed using physical vapor deposition method. For friction test, three brackets from each group were randomly selected and tested. For scanning electron microscopy and atomic-force microscopy assessments, one and one brackets were selected from each group. For antibacterial assessment, six brackets were selected from each group. Of them, three were immediately subjected to direct contact with S. mutans. Colonies were counted 3, 6, 24, and 48 h of contact. The other three were stored in water for 3 months. Then were subjected to a similar direct contact test. Results pertaining to both subgroups were combined. Groups were compared statistically. Mean (SD) friction values of the groups 'control, silver-60, silver-100, titanium-60, and titanium-100' were 0.55 ± 0.14, 0.77 ± 0.08, 0.82 ± 0.11, 1.52 ± 0.24, and 1.57 ± 0.41 N, respectively (p = .0004, Kruskal-Wallis). Titanium frictions were significantly greater than control (p < .05), but silver groups were not (p > .05, Dunn). In the uncoated group, colony count increased exponentially within 48 h. The coated groups showed significant reductions in colony count (p < .05, two-way-repeated-measures ANOVA). In conclusions, all four explained coatings reduce surface roughness and bacterial growth. Nano-titanium films are not suitable for friction reduction. Nano-silver results were not conclusive and need future larger studies., (© 2016 Wiley Periodicals, Inc.)

Introduction: Adult patients typically require high-quality orthodontic treatment for ceramic brackets, but some clinicians remain concerned about the bond strength of these brackets. Therefore, the aim of this study was to determine the shear bond strength and de-bonding characteristics of metallic and ceramic brackets bonded with two types of bonding agents., Methods: In an experimental study done in 2013 in Babol, Iran, 120 extracted human maxillary premolar teeth were randomly divided into four groups as follows: HM group: metallic bracket/conventional bonding agent; SM group: metallic bracket/Transbond self-etching primer; HC group: ceramic bracket/conventional bonding agent; SC group: ceramic bracket/Transbond self-etching primer. Twenty-four hours after thermocycling (1000 cycle, 5 °C-55 °C), the shear bond strength values were measured. The amount of resin remaining on the tooth surface (adhesive remnant index: ARI) was determined under a stereomicroscope. Enamel detachment index was evaluated under a scanning electron microscope. To perform statistical analysis, ANOVA, Kruskal-Wallis, and Tukey post-hoc tests were applied. The level of significance was set at p <0.05., Results: The mean shear bond strength values (MPa ± SD) were group HM=12.59, group SM=11.15, group HC=7.7, and group SC=7.41. Bond strength differences between groups HM and SM (p=0.063) and between HC and SC (p=0.091) were not statistically significant. There were significant differences between HM and HC and between SM and SC groups (p < 0.05). Insignificant differences were found in ARI among all groups., Conclusion: Our findings indicated that the metallic brackets had higher bond strengths in comparison with ceramic brackets. In addition, self-etching primer was able to produce fewer bonds compared with the conventional technique. Many samples showed the bracket-adhesive interface failure or failure inside the adhesive., Competing Interests: Conflict of Interest: There is no conflict of interest to be declared.

Objectives: To evaluate comparatively the effect of quercetin on postbleaching shear bond strength (SBS) and adhesive remnant index (ARI)., Materials and Methods: Intact maxillary premolars were divided randomly into 12 groups of 10 each: (1) bonding the bracket immediately after bleaching, (2) bonding 1 week after bleaching, (3-8) application of three experimental concentrations of quercetin (0.1%, 0.5%, and 1%) at two time durations (5 and 10 min), (9-10) application of the solvent of quercetin at two time periods (5 and 10 min), (11) application of 10% sodium ascorbate for 10 min, and (12) bonding the brackets on nonbleached teeth. Bleaching was performed using 15% carbamide peroxide gel for 5 days (6 h daily). After incubation and thermocycling, the SBS of brackets was measured. The ARI too was recorded at ×20. The data were analyzed statistically (α =0.05)., Results: Bleaching reduced the SBS below 10 Megapascal (MPa) level ( P < 0.05) while all the postbleaching treatments (except the application of the solvent of quercetin) recovered the SBS back to values greater than 10 MPa ( P < 0.05) and also back to nonbleached SBS levels ( P > 0.01). All eight postbleaching treatments had rather similar efficacies ( P = 0.1396). The concentration of quercetin (beta = 0.259, P = 0.042) but not its duration (beta = 0.213, P = 0.093) significantly improved its efficacy., Conclusion: Bleaching can weaken the bond strength of orthodontic brackets below acceptable levels. The application of quercetin or Vitamin C or delaying the bracket bonding improved the postbleaching SBS., Competing Interests: There are no conflicts of interest.

Aim: To investigate the skeletal, dental, and soft tissue changes in girls with class II division 1 malocclusion after growth spurt peak under the effect of activator appliance., Materials and Methods: In this clinical trial study, 15 female patients, with skeletal class II and mandibular growth deficiency and at least 5 mm overjet, were randomly selected 6 months after their menarche. The mean of their ages at the beginning was 12.33 ± 0.81 years, and in the end it was 13.73 ± 0.79 years; the mean duration of treatment was 12.2 ± 3.18 months. Lateral, cephalometric radiographs were taken from all the patients before and after the treatment. Data were analyzed with Statistical Package for the Social Sciences (SPSS) 20 using paired t-test., Results: On an average, the ANB angle, the angle of the upper incisors with the S-N, facial convexity, and overjet decreased by 2.6° ± 0.9, 5.4° ± 0.8, 3.8° ± 3.4, and 5.6 ± 1.8 mm respectively. The SNB angle, the angle of the lower incisors with the N-B, the labiomental angle, the total length of the mandible, the lower anterior facial height, the lower lip distance, the first molar of the mandible, and the soft tissue pogonion to the vertical line from the S point increased by 2.8° ± 1.8, 3.4° ± 3, 14.7 ± 15, 3.7 ± 2.6, 2.1 ± 1.6, 6.3 ± 2.5, 4.4 ± 2.4, and 6 ± 3.3 mm respectively. All these figures were statistically significant (p = 0.000)., Conclusion: The functional appliance improved the dental-skeletal relations and the soft tissue profile of patients after the growth spurt peak of puberty in a group of Iranian girls, whereas dental changes were more than skeletal ones., Clinical Significance: Functional appliances can be used for correction of skeletal class II malocclusion 6 months after menarche in girls.

Objectives: White spots and enamel demineralization around orthodontic brackets are among the most important complications resulting from orthodontic treatments. Since the antibacterial properties of metals and metallic particles have been well documented, the aim of this study was to assess the antibacterial effect of stainless steel orthodontic brackets coated with silver (Ag) particles., Materials and Methods: In this study, 40 standard metal brackets were divided into two groups of 20 cases and 20 controls. The brackets in the case group were coated with Ag particles using an electroplating method. Atomic force microscopy and scanning electron microscopy were used to assess the adequacy of the coating process. In addition, antibacterial tests, i.e., disk diffusion and direct contact tests were performed at three, six, 24, and 48 hours, and 15 and 30 days using a Streptococcus mutans strain. The results were analyzed using Student's t-test and repeated measures ANOVA., Results: Analyses via SEM and AFM confirmed that excellent coatings were obtained by using an electroplating method. The groups exhibited similar behavior when subjected to the disk diffusion test in the agar medium. However, the bacterial counts of the Ag-coated brackets were, in general, significantly lower (P<0.001) than those of their non-coated counterparts., Conclusions: Brackets coated with Ag, via an electroplating method, exhibited antibacterial properties when placed in direct contact with Streptococcus mutans. This antibacterial effect persisted for 30 days after contact with the bacteria.

Aims of the present study was to measure frictional resistance between silver coated brackets and different types of arch wires, and shear bond strength of these brackets to the tooth. In an experimental clinical research 28 orthodontic brackets (standard, 22 slots) were coated with silver ions using electroplate method. Six brackets (coated: 3, uncoated: 3) were evaluated with Scanning Electron Microscopy and Atomic Force Microscopy. The amount of friction in 15 coated brackets was measured with three different kinds of arch wires (0.019 × 0.025-in stainless steel [SS], 0.018-in stainless steel [SS], 0.018-in Nickel-Titanium [Ni-Ti]) and compared with 15 uncoated steel brackets. In addition, shear bond strength values were compared between 10 brackets with silver coating and 10 regular brackets. Universal testing machine was used to measure shear bond strength and the amount of friction between the wires and brackets. SPSS 18 was used for data analysis with t-test. SEM and AFM results showed deposition of a uniform layer of silver, measuring 8-10 μm in thickness on bracket surfaces. Silver coating led to higher frictional forces in all the three types of arch wires, which was statistically significant in 0.019 × 0.025-in SS and 0.018-in Ni-Ti, but it did not change the shear bond strength significantly. Silver coating with electroplating method did not affect the bond strength of the bracket to enamel; in addition, it was not an effective method for decreasing friction in sliding mechanics., (© Wiley Periodicals, Inc.)

Purpose: The aim of this study was to compare frictional forces between monocrystalline alumina (MA), polycrystalline alumina (PA), and stainless steel (SS) brackets with two SS wires: Rectangular and round., Materials and Methods: In this in vitro study, 60 0.022 brackets [20 PA (0° torque, Forestadent, Germany) and 20 MA (0° torque, Ormco, California, USA)] brackets plus 20 SS brackets (0° torque, Foretadent, Germany) and 60 SS archwires (30 rectangular 0.019 ×0.025 archwires and 30 round 0.018 archwires, Ortho Technology, USA) were used in subgroups of 10 from the combination of all brackets and all archwires. A universal testing machine (Instron, Model STM 250, Germany) was used to investigate the static frictional resistance. The angulation between the bracket and wire was 0°, and the wires were pulled through the slots at a crosshead speed of 10 mm/min. Two-way and one-way analyses of variance (ANOVA) and Tukey tests were used to analyze the data., Results: Mean (SD) static frictional force for each group was as follows: MA + round: 3.47 (0.38); MA + rectangular: 4.05 (0.47); PA + round: 4.14 (0.37); PA + rectangular: 4.45 (0.65); SS + round: 3.28 (0.22); and SS + rectangular: 4.22 (0.61). Significant effects of bracket types (P = 0.001) and archwire types (P = 0.000) on the friction force were detected using ANOVA. Tukey test indicated significant differences between PA brackets with both SS and MA brackets (P < 0.05), but not between SS and MA brackets. The two archwires as well had significantly different effects (Tukey P = 0.000)., Conclusions: Based on the present in-vitro study, the PA brackets might create higher frictional forces compared to both SS and MA brackets. The rectangular 0.019 ×0.025 archwire might create greater forces than round 0.018 archwire.

This research aimed to reduce the friction between the wire and brackets by Er:YAG laser. To measure the friction between the wires and brackets in 0° and 10° of wire angulations, 40 polycrystalline ceramic brackets (Hubit, South Korea) were divided into 8 study groups and irradiated by 100, 200, and 300 mj/s of Er:YAG laser power. Two groups of brackets were not irradiated. The friction between the wires and brackets was measured with universal testing machine (SANTAM) with a segment of .019 × .025 SS wire pulled out of the slot of bracket. ANOVA and t-test were used for analyzing the results. To evaluate the effect of the laser on surface morphology of the bracket, SEM evaluations were carried out. The mean frictional resistances between the brackets and wires with 0° of angulation by increasing the laser power decreased compared with control group, but, in 10° of angulation, the friction increased regardless of the laser power and was comparable to the friction of nonirradiated brackets. Furthermore, with each laser power, frictional resistance of brackets in 10° of angulation was significantly higher than 0° of angulation. These results were explained by SEM images too.

Background: Zinc (Zn) is an essential nutrient that is required in humans and animals for the growth, development, and maintenance of healthy bones. The aim of this study is to investigate the effects of zinc-deficient nutrition on the dental, mandibular, maxillary, and cranial dimensions of rats., Materials and Methods: This experimental study was carried out on 14 male Wistar rats. The rats were randomly divided into two groups. Group I rats were fed with a Zn-deficient (ZD) diet, and Group II rats with a Zn-containing (ZC) diet. All the rats on the experimental diet were killed at the end of the fourth week and their blood samples were taken. The serum Zn levels were measured by an atomic absorption spectrophotometer. Radiographic assessment of the jaw bone density was done at the end of the study. Subsequently, the final measurements were made on the dry skulls, the mandibles, and teeth in both the groups. Statistical evaluation was performed by the student's t-test and repeated measures analysis. The difference between the groups was considered statistically significant if P < 0.05., Results: The ZD group showed a significantly lower value in body weight (P < 0.05), serum level of zinc (P < 0.0001), and radiographic bone density of the mandible (P = 0.02). With regard to the craniofacial parameters, a significant difference was observed only in the length of the clinical crowns of the teeth (L13), which were longer in group II as compared to group I (P = 0.03)., Conclusion: This study confirmed that changes in zinc intake could not affect the growth of craniofacial structures. Also, it might change the radiographic bone density of the mandible.