Comparison of shear bond strength of bonded stainless steel brackets using three different light curing systems: An in vitro study.

OBJECTIVES: To evaluate and compare the shear bond strength of stainless-steel brackets using three different light curing units. MATERIAL AND METHODS: Using three LED curing units (3M ESPE Elipar, Ivoclar bluephase, and Woodpecker I LED light cure), 120 precoated metal brackets (Gemini series, 3M Unitek) were cured. The shear bond strength was recorded using a universal testing machine. RESULT: The shear strength of the bracket in different light-curing systems was examined with ANOVA test. The mean shear strength of group A, group B, and group C were 16.03 ± 14.30 MPA, 16.86 ± 11.89 MPA, and 20.51 ± 19.40, respectively. The result of the analysis shows that there is a major difference in shear bond strength of these three different light-curing systems with F value = 3.94 and P value 0.04. CONCLUSION: We used three LED light-curing units with different intensities and manufacturing companies. The result showed that woodpecker I LED light had significantly highest mean SBS than the other two (Elipar LED curing light and 3M ESPE, Ivoclar bluephase).

Comparative evaluation of displacement and stress distribution pattern during mandibular arch distalization with extra and inter-radicular mini-implants: a three-dimensional finite element study.

OBJECTIVE: To compare the initial stress distribution and displacement on mandibular dentition using extra and inter-radicular mini-implants for arch distalization, by means of finite element analysis. METHODS: For this study, two finite element models of the mandible were designed. The models consisted of periodontal ligament (PDL) and alveolar bone of all teeth until second molars. In the Case 1, bilateral extra-radicular buccal-shelf stainless steel mini-implants (10.0-mm length; 2.0-mm diameter) were placed between first and second permanent molars. In the Case 2, bilateral inter-radicular stainless steel mini-implants (10.0-mm length; 1.5-mm diameter) were placed between second premolar and first permanent molar. Power hook was attached between canine and first premolar at a fixed height of 8mm. In the two cases, 200g of distalization force was applied. ANSYS v. 12.1 software was used to analyze and compare von Mises stress and displacement in the mandibular dentition, PDL and bone. RESULTS: Higher stresses were observed in mandibular dentition with the inter-radicular implant system. The amount of von Mises stress was higher for cortical bone (85.66MPa) and cancellous bone (3.64MPa) in Case 2, in comparison to cortical bone (41.93MPa) and cancellous bone (3.43MPa) in Case 1. The amount of arch distalization was higher for mandible in Case 1 (0.028mm), in comparison to Case 2 (0.026mm). CONCLUSION: Both systems were clinically safe, but extra-radicular implants showed more effective and controlled distalization pattern, in comparison to inter-radicular implants, in Class III malocclusion treatment.

Comparative evaluation of displacement and stress distribution pattern during mandibular arch distalization with extra and inter-radicular mini-implants: a three-dimensional finite element study

ABSTRACT Objective: To compare the initial stress distribution and displacement on mandibular dentition using extra and inter-radicular mini-implants for arch distalization, by means of finite element analysis. Methods: For this study, two finite element models of the mandible were designed. The models consisted of periodontal ligament (PDL) and alveolar bone of all teeth until second molars. In the Case 1, bilateral extra-radicular buccal-shelf stainless steel mini-implants (10.0-mm length; 2.0-mm diameter) were placed between first and second permanent molars. In the Case 2, bilateral inter-radicular stainless steel mini-implants (10.0-mm length; 1.5-mm diameter) were placed between second premolar and first permanent molar. Power hook was attached between canine and first premolar at a fixed height of 8mm. In the two cases, 200g of distalization force was applied. ANSYS v. 12.1 software was used to analyze and compare von Mises stress and displacement in the mandibular dentition, PDL and bone. Results: Higher stresses were observed in mandibular dentition with the inter-radicular implant system. The amount of von Mises stress was higher for cortical bone (85.66MPa) and cancellous bone (3.64MPa) in Case 2, in comparison to cortical bone (41.93MPa) and cancellous bone (3.43MPa) in Case 1. The amount of arch distalization was higher for mandible in Case 1 (0.028mm), in comparison to Case 2 (0.026mm). Conclusion: Both systems were clinically safe, but extra-radicular implants showed more effective and controlled distalization pattern, in comparison to inter-radicular implants, in Class III malocclusion treatment.

RESUMO Objetivo: Comparar a distribuição da tensão inicial e o deslocamento na dentição inferior usando mini-implantes extra e inter-radiculares para distalização da arcada, por meio da análise de elementos finitos. Métodos: Dois modelos de elementos finitos da mandíbula foram criados, os quais consistiram de ligamento periodontal (PDL) e osso alveolar de todos os dentes até os segundos molares. No Caso 1, mini-implantes extra-radiculares de aço inoxidável (10,0 mm de comprimento; 2,0 mm de diâmetro) foram colocados bilateralmente na buccal-shelf entre o primeiro e o segundo molares permanentes. No Caso 2, mini-implantes de aço inoxidável inter-radiculares (comprimento de 10,0 mm; diâmetro de 1,5 mm) foram colocados bilateralmente entre o segundo pré-molar e o primeiro molar permanentes. Um Power hook foi preso entre o canino e o primeiro pré-molar a uma altura fixa de 8mm. Nos dois casos, foi aplicada força de distalização de 200g. O software ANSYS v. 12.1 foi usado para analisar e comparar a tensão de von Mises e o deslocamento na dentição inferior, ligamento periodontal e osso. Resultados: Maiores tensões foram observadas na dentição inferior com o sistema de implantes inter-radiculares. A quantidade de tensões de von Mises foi maior para osso cortical (85,66MPa) e osso esponjoso (3,64MPa) no Caso 2, em comparação com osso cortical (41,93MPa) e osso esponjoso (3,43MPa) no Caso 1. A quantidade de distalização da arcada inferior foi maior no Caso 1 (0,028 mm), em comparação com o Caso 2 (0,026 mm). Conclusão: Ambos os sistemas foram clinicamente seguros, mas os implantes extra-radiculares mostraram um padrão de distalização mais eficaz e controlado, em comparação com os implantes inter-radiculares, para tratamento da má oclusão de Classe III.

Analysis of initial stress distribution in palatal bone around the implant in lingual orthodontics for single and double palatal implant systems: a FEM study.

OBJECTIVE: To analyze and compare the Von Mises stress and principal stress distribution in palatal bone around the palatal implant in lingual orthodontics (LiO) for single and double palatal implant systems with varying lengths of lever arm. METHODS: Two groups were assessed: single (Group 1) and double (Group 2) palatal implant systems, which were further divided into two subgroups, based on lever arm length, for analyzing stress in the palatal bone around the implant. Hence, two 3D finite element models of bilateral maxillary first premolar extraction cases were constructed in each system. Lingual brackets (0.018-in slot) were positioned at the center of the clinical crown. In both systems, 150g of retraction force was applied, and ANSYS v. 12.1 software was used to analyze and compare stress in the palatal bone around the palatal implant. RESULTS: In this study, higher stress was observed at the inner threaded interface of cortical bone. Magnitude of Von Mises stress was higher in Group 2 (0.63 MPa and 0.65 MPa) in comparison to Group 1 (0.29 MPa and 0.29 MPa). Similarly, magnitude of principal stress was higher in Group 2, in comparison to Group 1. Higher stress was observed in the apical region of the implant-bone interface of cancellous bone. CONCLUSION: This study concluded that the Von Misses stress as well as principal stress in the palatal bone were within the optimal limit in both groups. Finally, it can be concluded that both systems (single and double palatal implant) were safe for the patients in clinical use of 150g of retraction force.

Analysis of initial stress distribution in palatal bone around the implant in lingual orthodontics for single and double palatal implant systems: a FEM study

ABSTRACT Objective: To analyze and compare the Von Mises stress and principal stress distribution in palatal bone around the palatal implant in lingual orthodontics (LiO) for single and double palatal implant systems with varying lengths of lever arm. Methods: Two groups were assessed: single (Group 1) and double (Group 2) palatal implant systems, which were further divided into two subgroups, based on lever arm length, for analyzing stress in the palatal bone around the implant. Hence, two 3D finite element models of bilateral maxillary first premolar extraction cases were constructed in each system. Lingual brackets (0.018-in slot) were positioned at the center of the clinical crown. In both systems, 150g of retraction force was applied, and ANSYS v. 12.1 software was used to analyze and compare stress in the palatal bone around the palatal implant. Results: In this study, higher stress was observed at the inner threaded interface of cortical bone. Magnitude of Von Mises stress was higher in Group 2 (0.63 MPa and 0.65 MPa) in comparison to Group 1 (0.29 MPa and 0.29 MPa). Similarly, magnitude of principal stress was higher in Group 2, in comparison to Group 1. Higher stress was observed in the apical region of the implant-bone interface of cancellous bone. Conclusion: This study concluded that the Von Misses stress as well as principal stress in the palatal bone were within the optimal limit in both groups. Finally, it can be concluded that both systems (single and double palatal implant) were safe for the patients in clinical use of 150g of retraction force.

RESUMO Objetivo: Analisar e comparar as tensões de Von Mises e a distribuição das tensões principais no osso palatino ao redor de implantes palatinos em Ortodontia Lingual (OL) para sistemas de implantes palatinos unitários ou duplos com comprimentos variados do braço de alavanca. Métodos: Foram delineados dois grupos para o presente estudo: Grupo 1 - com sistema de implante palatino unitário e Grupo 2 - com sistema de implantes palatinos duplos. Em seguida, os grupos foram divididos em dois subgrupos, com base no comprimento do braço de alavanca, para analisar as tensões no osso palatino ao redor do implante. Para cada sistema, foram construídos dois modelos 3D de elementos finitos (MEF) de casos com extração bilateral de primeiros pré-molares superiores. Braquetes linguais (slot 0,018") foram posicionados no centro das coroas clínicas. Nos dois sistemas, foram aplicados 150g de força de retração nos dentes anteriores, e o software ANSYS v. 12.1 foi usado para analisar e comparar as tensões no osso palatino ao redor dos implantes. Resultados: Foram observados maiores níveis de tensões na parte interna rosqueada no osso cortical. A magnitude das tensões de Von Mises foi maior no Grupo 2 (0,63MPa e 0,65MPa) em comparação ao Grupo 1 (0,29MPa e 0,29MPa). De forma semelhante, foi observada maior magnitude das tensões principais no Grupo 2 do que no Grupo 1. Maiores tensões foram observadas na região apical da interface osso/implante no tecido ósseo esponjoso. Conclusão: A tensões de Von Mises e as tensões principais no osso palatino ficaram dentro do limite ideal em ambos os grupos. Ambos os sistemas de implantes palatinos (unitário e duplo) foram seguros para o uso clínico em pacientes com força de retração de 150g.

A Comparative Evaluation of Smear Layer Removal by Using Four Different Irrigation Solutions like Root Canal Irrigants: An In Vitro SEM Study.

BACKGROUND: The present study aimed to evaluate and compare the efficacy of 17% ethylenediaminetetraacetic acid (EDTA), 18% etidronic acid, 10% citric acid, and 7% maleic acid in the removal of smear layer at the apical third of the root canals. MATERIALS AND METHODS: Sixty single-rooted teeth were equally divided into four study groups (n = 15), according to the type of irrigant used (17% EDTA, 18% etidronic acid, 10% citric acid, and 7% maleic acid) to remove the smear layer effectively from apical third of root canal. In each group, respective irrigant was used with 5.25% of sodium hypochlorite during instrumentation. Each study sample was then sectioned longitudinally and removal of smear layer was observed using a scanning electron microscope (SEM) at 2000×. RESULTS: A 7% maleic acid revealed better smear layer removal than all other three groups at apical third. A 10% citric acid was found to be more efficient than EDTA and etidronic acid. The intergroup comparison was performed using Mann-Whitney U test, and there was no significant difference between all the study groups, except maleic acid. CONCLUSION: The present study compared the effect of various irrigants as an adjunct with 5.25% of sodium hypochlorite for root canal irrigation during and after instrumentation. The use of irrigants aids in the removal of the smear layer from the root canals, thereby increasing the success rate of endodontic therapy. CLINICAL SIGNIFICANCE: This study supports the hypothesis that a thorough use of root canal irrigants can efficiently remove the smear layer which is the key for successful root canal treatment. The present study helps in choosing an appropriate irrigant that can ensure complete root canal debridement from all thirds, especially from the apical third of the root canal. How to cite this article: Mankeliya S, Singhal RK, Gupta A, et al. A Comparative Evaluation of Smear Layer Removal by Using Four Different Irrigation Solutions like Root Canal Irrigants: An In Vitro SEM Study. J Contemp Dent Pract 2021;22(5):527-531.

Comparative evaluation of displacement and stress distribution pattern during maxillary arch distalization with Infra Zygomatic Screw- A three dimensional finite element study.

OBJECTIVE: This study aimed to evaluate and compare the distribution of stress and displacement of teeth during maxillary arch distalization with IZC (Infra zygomatic crest) screw with two maxillary positions and different lever arm heights. SETTINGS AND DESIGN: Six three-dimensional finite element models of the maxillary arch were constructed with third molars extracted. Models 1, 2 and 3: IZC 6 (mesial to mesiobuccal root of first molar, 6) with 0mm, 4mm and 8mm lever arm height; Models 4, 5 and 6: IZC 7 (mesial to mesiobuccal root of second molar, 7) with 0mm, 4mm and 8mm, respectively. MATERIAL AND METHODS: MBT preadjusted Brackets (slot size 0.022×0.028") were placed over the clinical crown's centre with 0.019×0.025" stainless steel archwire on all six models. Retraction force of 4N was applied with different combinations of IZC screws and lever arm bilaterally using Nickel-Titanium (NiTi) closed coil spring. Then, evaluation of stress distribution, von Mises stress and maxillary teeth displacement were performed using ANSYS 12.1 software. RESULTS: In this study, maximum von Mises stress in alveolar bone (cortical bone) was observed in Model 4 (107.79MPa) at the screw fixation site that was within the optimum limit (135MPa). Different extents of displacements like labiolingual tipping of crown, labiolingual tipping of root, extrusion and intrusion were noticed. The models with 0mm and 4mm lever arm height (models1, 2, 4 and 5) showed more controlled crown and root movements in comparison to 8mm long lever arm models (models 3 and 6). In model 5, a maximum distal movement compared to all other five models was observed. CONCLUSIONS: IZC 7 position showed the most favourable results (maximum distalization) with the lever arm height of 4mm. Therefore, the nearer the force to the centre of resistance of the tooth, the greater is distalization. Stresses on the IZC screw decreases when lever arm height increases, in all the models.

Analysis of stress distribution in lingual orthodontics system for effective en-masse retraction using various combinations of lever arm and mini-implants: A finite element method study.

INTRODUCTION: The aims and objectives of this study were to evaluate the von Mises stress and principal stress distribution and displacement of anterior teeth in a lingual orthodontics system along the periodontal ligament and alveolar bone by various combinations of mini-implants and lever arm during en-masse retraction. Four 3-dimensional finite element (FE) models of the bilateral maxillary first premolar extraction cases were constructed. METHODS: Lingual brackets were (0.018-in slots) positioned over the center of the clinical crown. In all 4 models, 150 g of retraction force was applied with the help of a nickel-titanium closed coil spring with different combinations of mini-implants and lever arm on each side. FE analysis was then performed to evaluate stress distribution, principal stress, von Mises stress, and displacement of the anterior teeth using ANSYS software (version 12.1; Ansys, Canonsburg, Pa). The FE study was enough to validate the analysis results obtained by software tools with FE simulation instead of experimental readings. Thus, statistical analysis was not required. RESULTS: In this study, maximum tensile stresses were observed in the periodontal ligament at the mesial cervical region of the canine with values of 1.84 MPa, 2.02 MPa, 1.88 MPa, and 2.08 MPa for models 1-4, respectively. Maximum von Mises stress in alveolar bone was 8.05 MPa, 8.23 MPa, 8.19 MPa, and 8.37 MPa for models 1-4, respectively, which was within the optimum limit (135 MPa). Variable amounts of displacements like lingual crown tipping, lingual root tipping, and extrusion were observed in all the models. The 15-mm long lever arm models (models 2 and 4) showed a more controlled crown (0.015 mm) and root movement (0.004 mm) compared with 12-mm long lever arm models (models 1 and 3). CONCLUSIONS: In lingual orthodontics, controlled root movement increased as we increased the length of the lever arm. It was also concluded that the amount of increased controlled tipping found with the placement of the mini-implant was toward the palatal slope.