The Effect of Bonding Surface Design on Shear Bond Strength of 3D-Printed Orthodontic Attachments.

Introduction: This study compared the shear bond strength (SBS) of four innovative designs of the bonding surface of 3D-printed orthodontic attachments with conventional mesh design. Methods: In this in vitro study, the bonding surface design in different groups was as follows: Group 1, flat surface without any feature as a negative control; Group 2, concentric circles with no cuts; Group 3, concentric circles with 16 radial cuts; Group 4, concentric circles with 32 radial cuts; Group 5, small cones with a flat end and rounded edges; Group 6, mesh-based commercially available metal brackets of the maxillary central incisor (standard edgewise, Dentaurum®) as a positive control (n = 20). In Groups 1-5, attachments were designed with SolidWorks® Software and printed with a 2K DLP-LCD printer with hard tough resin (eSun®). All the samples were bonded to the restorative composite resin (Solafil®) surfaces with orthodontic composite resin (CuRAY-ECLIPSE®). The samples were examined for SBS with a universal testing machine after thermocycling (1,000 cycles of 5‒55°C). Data were analyzed with Shapiro-Wilk, one-way ANOVA, and Bonferroni tests. The statistical significance level was set at 0.05. Results: The mean SBS was significantly different between all the groups (P < 0.001) except for Groups 2 and 5 (P = 1.00) and Groups 2 and 6 (P = 1.00). Group 4 had the highest mean of SBS. Conclusion: The bonding surface design significantly influenced the SBS of orthodontic attachments. The concentric circles with 32 cuts had higher bond strength than other designs and can be suggested as a new bonding surface design for orthodontic attachments.

Bonding Surface Designs in Fixed Orthodontic Attachments.

Fixed orthodontic attachments/appliances work as a medium to transfer the force applied to the teeth. In bonded types, several factors affect the attachment bond strength and their clinical success. The primary approach for increasing the bond strength focused on altering the time and concentration of acid etching; however, the results showed that these changes might increase susceptibility to enamel decalcification. The bonding mechanism of orthodontic attachments may be chemical, mechanical, or a combination of both. Most attachment bonding surfaces (ABSs) have no chemical bond to resin composites. Hence, mechanical retention plays a major role. Developing more bonding surfaces by increasing the macroscopic size of the attachments has esthetic and hygienic limitations, so the ABS design plays a more important role in maintaining and improving the bond strength. In this research, different ABS designs are reviewed and categorized according to manufacturing methods and their features.

Effect of hydrochloric acid, sodium hypochlorite, and autoclave sterilization on the force characteristics of orthodontic NiTi-closed coils.

Background: This study presented a cleaning method for orthodontic NiTi-closed coils and evaluated its effect on the force characteristics of these coils. Materials and Methods: In this in vitro study, 160 orthodontic NiTi-closed coils, 160 orthodontic NiTi-closed coils (9 mm) from two brands G and H and DB, randomly assigned into four groups. Group 1: Three times of immersion in the 10% hydrochloric acid (HCI) solution for 1 min followed by the immersion in 5.25% sodium hypochlorite solution for 5 min. Group 2: Three times autoclave sterilization. Group 3: Three times of immersion in 10% HCI solution for 1 min, followed by the immersion in 5.25% sodium hypochlorite solution for 5 min and autoclave sterilization. Group 4: No immersion and no sterilization. The forces of coils were measured at 25, 23, 21, 19, and 17 mm extension. To measure the force characteristics of coils, an electromechanical universal testing machine was used. For the statistical analysis, Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U-tests were used at 0.05 significance level. Results: In G and H coils, no significant differences between the mean forces of different groups were found in any extensions. In DB coils, only in 25 mm extension, there were no significant differences between the groups (P = 0.144). In 17-, 19-, and 21-mm extensions, significant differences (P < 0.001) were found like in 23 mm extension (P = 0.05). In both brands, more extension makes significant more forces statistically (P < 0.01). In all extensions, G and H coils have significant less forces (P < 0.001). Conclusion: Immersion in HCl, 10% for 1 min followed by the immersion in NaOCl, 5.25% for 5 min followed by autoclave sterilization, even three times repeating of this process, did not result in significant changes in the force characteristics of A-NiTi-closed coils.

The effect of hydrochloric acid and sodium hypochlorite on fracture resistance of orthodontic self-cure acrylic base.

Background: Patient cooperation is necessary for treatment success in removable orthodontics. Every factor has an adverse effect on appliances appearance can impede appliance wearing. This study investigated the effect of immersion in household cleaner and bleach liquids on fracture resistance of self-cure orthodontic acrylic resins. Materials and Methods: This in vitro study two orthodontic acrylic resins (Megadental® and Acropars®) were used. Eighty identical acrylic samples (50 mm × 5 mm × 3 mm) from each acrylic resin were fabricated and divided into four groups (n = 20). For each type of acrylic resin; Group 1: 15 min immersion in household cleaner liquid (hydrochloric acid [HCl], 10%), 1 min rinsing with running water, 15 min immersion in household bleach liquid (sodium hypochlorite [NaOCl], 5.25%) and 1 min rinsing with running water were done. For Group 2, two times and for Group 3, three times immersion just like Group 1, were done. Group 4, as control, had no immersion. Fracture resistance of samples was measured with universal testing machine (Instron) in 3-point bending set-up. Data were analyzed with two-way repeated measurement ANOVA. Significance level was set at 0.05. Results: Fracture resistance of Acropars groups was greater than counterpart Megadental ones (P < 0.001). Immersion factor, alone (P = 0.375) and in combination with material (P = 0.603), did not make a significant difference among fracture resistance of each acrylic resin groups. Conclusion: 15 min immersion in household cleaner liquid (HCl acid) followed by 15 min immersion in household bleach liquid (NaOCl 5.25%) and even 3 times repetition of this process had not significant adverse effect on fracture resistance of acrylic resins.

Effect of immersion in hydrochloric acid and sodium hypochlorite and autoclave sterilization on the force characteristics of orthodontic nickel-titanium open coils.

BACKGROUND: Nickel-titanium (NiTi) open coils are common tools in fixed orthodontic treatments to apply light and continuous forces. Their favorable mechanical properties and their relatively high cost have prompted many clinicians to decide to reuse them. AIM: The present study aimed to evaluate the effect of 10% hydrochloric acid (HCl) and 5.25% sodium hypochlorite (NaClO) solution and sterilization, on the unloading force of NiTi open-coils. MATERIALS AND METHODS: This experimental in vitro study consisted of 160 NiTi open coils from two brands of Highland Metals and Masel were provided. Each group was randomly divided into four subgroups: control, three rounds of immersion, three rounds of autoclave sterilization, and three rounds of immersion and autoclaving. Each round of immersion process included 1 min in 10% HCl, followed by 5 min in 5.25% NaClO. Spring was compressed for 4 mm. Then, the unloading forces of each spring were recorded at 4, 3, 2, and 1 mm of compression, respectively. The data were analyzed with SPSS (P < 0.05), using one-way ANOVA and independent t-test. RESULTS: One-way ANOVA showed a significant difference in the 2-mm compression of Group 1 and 3-mm compressions of Groups 1 and 2 compared to the control group in the Highland metals brand (P < 0.04, P < 0.014, and P < 0.007, respectively). There was no significant difference between the different compressed lengths and groups in the Masel brand. CONCLUSION: One-minute immersion in 10% HCL and 5-min immersion in 5.25% NaOCl, followed by autoclave sterilization, even after repeating the process three times, did not significantly change the force properties of NiTi open springs. Therefore, the re-use of these springs with the above-mentioned method as preparation can be recommended.

Chair time saving method for treatment of an impacted maxillary central incisor with 15-month follow-up.

Maxillary permanent incisors have a major role in facial esthetics. Impaction of them has great adverse effect on smile and causes serious concerns in patient and parents. Physical barriers (e.g., overretained primary teeth, supernumerary teeth, and pathologic lesions), space problems, developmental abnormalities, altered eruption sequence, trauma, palatal clefts, and genetics can act as etiologic factors. Currently, the conventional technique to treatment of impacted teeth consists of a combined orthodontic and surgical approach, to guide the impacted teeth in a constant position and surrounded by normal hard and soft tissues. Treatment is challenging because of some limitations such as patient's age, cooperation, anchorage, and mechanotherapy possibilities. Hence, sophisticated treatment planning is crucial. A 9-year-old girl with horizontally impacted maxillary left central incisor treated with surgical exposure and closed orthodontic forced eruption with 2 × 4 partial setup fixed appliances. Force was applied with 0.014 inch nickel-titanium wire as elastic overlay and handmade ligated bracket. To save chair time in each appointment, the overlay was activated by twisting of ligature wire extensions around it. After 16-month treatment, impacted incisor emerged in oral cavity, with accepted alignment and inclination. Handmade ligated bracket with ligature wire extensions is useful for the treatment of impacted teeth. Due to easy activation of overlay in this method, chair time become short in each appointment.

Bilateral en-masse distalization of maxillary posterior teeth with skeletal anchorage: a case report.

OBJECTIVE: The aim of this study was to introduce a new method for bilateral distal movement of the entire maxillary posterior segment. CASE REPORT: A 17-year-old girl with Class I skeletal malocclusion (end-to-end molar relationships, deviated midline and space deficiency for left maxillary canine) was referred for orthodontic treatment. She did not accept maxillary first premolars extraction. A modified Hyrax appliance (Dentaurum Ispringen, Germany) was used for bilateral distalization of maxillary posterior teeth simultaneously. Expansion vector was set anteroposteriorly. Posterior legs of Hyrax were welded to first maxillary molar bands. All posterior teeth on each side consolidated with a segment of 0.017 × 0.025-in stainless steel wire from the buccal side. Anterior legs of Hyrax were bent into eyelet form and attached to the anterior palate with two mini-screws (2 × 10 mm) (Jeil Medical Corporation Seoul, South Korea). Hyrax opening rate was 0.8 mm per month. Lateral cephalometric radiographs were used to evaluate the extent of distal movement. 3.5-mm distalization of posterior maxillary teeth was achieved in five months. RESULTS: A nearly bodily distal movement without anchorage loss was obtained. CONCLUSION: The mini-screw-supported modified Hyrax appliance was found to be helpful for achieving en-masse distal movement of maxillary posterior teeth.

Bilateral en-masse distalization of maxillary posterior teeth with skeletal anchorage: a case report

ABSTRACT Objective: The aim of this study was to introduce a new method for bilateral distal movement of the entire maxillary posterior segment. Case report: A 17-year-old girl with Class I skeletal malocclusion (end-to-end molar relationships, deviated midline and space deficiency for left maxillary canine) was referred for orthodontic treatment. She did not accept maxillary first premolars extraction. A modified Hyrax appliance (Dentaurum Ispringen, Germany) was used for bilateral distalization of maxillary posterior teeth simultaneously. Expansion vector was set anteroposteriorly. Posterior legs of Hyrax were welded to first maxillary molar bands. All posterior teeth on each side consolidated with a segment of 0.017 × 0.025-in stainless steel wire from the buccal side. Anterior legs of Hyrax were bent into eyelet form and attached to the anterior palate with two mini-screws (2 × 10 mm) (Jeil Medical Corporation Seoul, South Korea). Hyrax opening rate was 0.8 mm per month. Lateral cephalometric radiographs were used to evaluate the extent of distal movement. 3.5-mm distalization of posterior maxillary teeth was achieved in five months. Results: A nearly bodily distal movement without anchorage loss was obtained. Conclusion: The mini-screw-supported modified Hyrax appliance was found to be helpful for achieving en-masse distal movement of maxillary posterior teeth.

RESUMO Objetivo: o objetivo do presente estudo foi apresentar um novo método para a distalização bilateral de todo o segmento posterior superior. Relato do caso: uma jovem de 17 anos de idade, com má oclusão esquelética de Classe I (relação de molares em topo a topo, linha média desviada e deficiência de espaço para o canino superior esquerdo) foi encaminhada para tratamento ortodôntico, mas recusou-se a autorizar a extração dos primeiros pré-molares superiores. Um aparelho Hyrax modificado (Dentaurum, Ispringen, Alemanha) foi utilizado para a distalização bilateral simultânea dos dentes posteriores superiores. O vetor de expansão foi definido no sentido anteroposterior. As barras de conexão posteriores do Hyrax foram soldadas às bandas dos primeiros molares superiores. Em cada um dos lados, todos os dentes posteriores foram agrupados com um segmento de fio de aço inoxidável de calibre 0,017" x 0,025" passando por vestibular. As barras de conexão anteriores do Hyrax foram dobradas em forma de loop e conectadas à região anterior do palato por meio de dois mini-implantes (2 x 10mm) (Jeil Medical Corporation, Seoul, Coreia do Sul). A taxa de abertura do Hyrax foi de 0,8mm / mês. Telerradiografias laterias foram usadas para avaliar a extensão dos movimentos de distalização. Resultados: em um prazo de cinco meses, foi obtida uma distalização de 3,5mm dos dentes posteriores superiores. O movimento realizado foi praticamente de corpo (translação), sem qualquer perda de ancoragem. Conclusão: o aparelho Hyrax modificado suportado por mini-implantes mostrou-se útil para efetuar o movimento de distalização em massa dos dentes posteriores superiores.

The effect of multiple processing and re-use on orthodontic mini-screw torque values.

BACKGROUND: Reusing orthodontic mini-screws would reduce treatment cost and lead to more use of mini-screws and improvement of orthodontic treatments. This study has assessed the effects of reprocessing and reusing the titanium mini-screws on their maximum insertion, removal and fracture torque (FT). MATERIALS AND METHODS: In this experimental study, 20 titanium mini-screws (1.6-mm × 8-mm) were randomly divided into two equal groups. In the test group, the screws were first sterilized by autoclave and then their FT was assessed. In the control group, FT was assessed after 5 times of insertion, cleaning, processing (37% phosphoric acid for 10 min, 5.25% sodium hypochlorite for 30 min) and sterilizing with autoclave. The maximum insertion and removal torque values were compared using the repeated measure ANOVA and the FT data were analyzed by the t-test. The data were analyzed using the SPSS software (version 13.0) and the significance was set on 0.05. RESULTS: The paired t-test for maximum insertion torque (MIT) showed that MIT1 was significantly lower than other MIT values (P = 0.02) and also MIT2 was significantly higher than MIT5 (P = 0.01), but other MIT values had no significant differences. The paired t-test for maximum removal torque (MRT) showed that only MRT2 was significantly higher than other MRT values (except MRT1) (P = 0.046). Regarding FT, the t-test showed that there was no significant difference between FT0 and FT5 (P = 0.485). CONCLUSION: Within limitations of this study, five time insertion, cleaning, processing and steam sterilization had no significant negative effect on insertion, removal and FT of the mini-screws.

Non-compliance Appliances for Upper Molar Distalization: An Overview.

Tooth Size Arch-length Discrepancy (TSALD) is a common problem in orthodontics. Its clinical signs are tooth crowding, impaction and incisor proclination. The treatment options are dental arch expansion or tooth mass reduction (stripping or extraction). The "extraction versus non-extraction" controversy has been widely debated in the orthodontic literature. Distalization is a kind of arch expansion in anetro-posterior dimension. Several studies have evaluated both the therapeutic effectiveness and the side effects of the appliances for this method of space gaining. In some cases molar distalization is preferred, e.g., a patient with acceptable profile and skeletal pattern and half cusp Class II molar malocclusion or even less. In some cases molar distalization is the only way, e.g., the patient with previous upper premolar extraction and excessive overijet, or a skeletal Class III patient with previous upper premolar extraction needed upper anterior teeth retraction to create reverse overjet aspre surgical orthodontic decompensation. In this review article, we described non-compliance upper molar distalizing appliances.

The effect of insertion angle on orthodontic mini-screw torque.

BACKGROUND: Primary stability is an important factor for the clinical success of orthodontic mini-screws. The present study made an attempt to evaluate the effect of insertion angle changes on the maximum insertion and removal torque of orthodontic mini-screws. MATERIALS AND METHODS: In this experimental study, 72 mini-screws (Dual Top Anchor System, Jeil, 1.6 mm diameter, 8 mm length) were used. They were randomly divided into four equal groups and inserted in poly-carbonate plates with 3 mm thickness. Then, their maximum insertion torque (MIT) and maximum removal torque (MRT) were recorded using a digital torque tester/screwdriver. Each group had a different insertion angle (90°, 75°, 60° and 45°). The data were analyzed by SPSS software (version 18) using one-way ANOVA and post-hoc Tukey's tests. The level of significance was set at 0.05. RESULTS: The maximum MIT was observed in 45° insertion angle (14.84 Ncm) and the minimum MIT was reported in 75° insertion angle (12.66 Ncm). The maximum MRT was observed in 45° insertion angle (23.21 Ncm) and the minimum MRT was reported in the 90° insertion angle (17.43 Ncm). CONCLUSION: Oblique insertion of the mini-screws results in higher insertion and removal torques and probably more primary stability compared to the vertical insertion.

A processing method for orthodontic mini-screws reuse.

BACKGROUND: The possibility of mini-screws reuse would reduce treatment cost. The aim of this study is to introduce a new method (application of phosphoric acid 37% for 10 minutes followed by sodium hypochlorite 5.25% for 30 minutes) for cleansing of mini-screws and assessing the efficacy of this method. The effects of this processing on the insertion, removal, and fracture torques of mini-screws were evaluated. MATERIALS AND METHODS: This experimental study was done in two parts. In part I the amount of calcium ion on mini-screws surfaces as an index of tissue remnants was assessed. In part II of this study, the effects of previous use, processing method, and resterilization on the insertion, removal, and fracture torques of mini-screws were assessed. Each part of this study had 3 groups; non-processed used (NP), processed used (P), and as-received (C). Each group had 16 samples in part I and 20 samples. Non parametric statistical tests were used in part I and one way ANOVA in part II. RESULTS: The mean amount of calcium ion in groups non-processed (NP1), processed (P1), and control (C1) were 4.7, 0.43, and 0.02 ppm, respectively. The amount of calcium ion in group NP1 was significantly greater than in the other groups (P = 0.000), but the difference between groups P1 and C1 was not significant (P = 0.087). The mean insertion torque of group NP2 was lower than that of other groups (P < 0.05) but P2 and C2 did not have significant differences (P = 0.988). The mean of removal and fracture torque did not have significant differences among all groups. CONCLUSION: Cleaning of used mini-screws with phosphoric acid 37% (10 minutes) and sodium hypochlorite 5.25% (30 minutes) reduces tissue remnants to the level of as-received mini-screws. So it can be suggested as a processing method of used mini-screws. Previous insertion of mini-screws into the bone and above-mentioned processing method and resterilization with autoclave had no adverse effects on insertion, removal, and fracture torque values as mechanical properties indices.

Forced eruption of adjoining maxillary premolars using a removable orthodontic appliance: a case report.

Forced eruption can be performed in teeth with caries, fracture, resorption or perforation in the cervical third of the root or isolated teeth with one- or two-walled vertical periodontal defects. The purpose of this case report is to introduce an innovative orthodontic appliance which enables forced eruption. This appliance is easy to fabricate, cost-effective and very effective in forced eruption of non-restorable teeth.