The effect of micro-osteoperforations on the rate of maxillary incisors' retraction in orthodontic space closure: a randomized controlled clinical trial.

BACKGROUND: This single-centered randomized controlled clinical trial aimed to evaluate the effectiveness of micro-osteoperforations (MOPs) in accelerating the orthodontic retraction of maxillary incisors. METHODS: Forty-two patients aged 16-40 were recruited and randomly assigned into two groups, one which underwent MOPs (MOPG) in the buccal and palatal region of all maxillary incisors immediately before the start of retraction and one which did not (CG). Eligibility criteria included the orthodontic need for maxillary first premolars extraction and space closure in two phases. The primary outcome of the study consisted of measuring the rate of space closure and, consequently, the rate of incisors' retraction using digital model superimposition 14 days later and monthly thereafter for the next 4 months. The secondary outcomes included measuring anchorage loss, central incisors' inclination, and root length shortening, analyzed using cone beam computed tomography scans acquired before retraction and 4 months after retraction. Randomization was performed using QuickCalcs software. While clinical blinding was not possible, the image's examinator was blinded. RESULTS: Twenty-one patients were randomly assigned to each group. However, due to various reasons, a total of 37 patients (17 male and 20 female) were analyzed (mean age: 24.3 ± 8.1 years in the MOPG; 22.2 ± 4.2 years in the CG) during the trial. No statistically significant difference was found between the MOPG and the CG regarding the incisors' retraction measured at different time points at the incisal border (14 days, 0.4 mm vs. 0.5 mm; 1 month, 0.79 mm vs. 0.77 mm; 2 months, 1.47 mm vs. 1.41 mm; 3 months, 2.09 mm vs. 1.88 mm; 4 months, 2.62 mm vs. 2.29 mm) and at the cervical level (14 days, 0.28 mm vs. 0.30 mm; 1 month, 0.41 mm vs. 0.32 mm; 2 months, 0.89 mm vs. 0.61 mm; 3 months, 1.36 mm vs. 1.10 mm; 4 months, 1.73 mm vs. 1.39 mm). Similarly, no statistically significant differences were detected in the space closure, anchorage loss, central incisors' inclination, and radicular length between groups. No adverse effect was observed during the trial. CONCLUSIONS: MOPs did not accelerate the retraction of the maxillary incisors, nor were they associated with greater incisor inclination or root resorption. Trial registration ClinicalTrials.gov NCT03089996. Registered 24 March 2017- https://clinicaltrials.gov/ct2/show/NCT03089996 .

Craniofacial morphology of patients with unilateral cleft lip and palate at two stages of skeletal maturation.

The aim of this retrospective cross-sectional investigation was to perform a 3D analysis of craniofacial morphology of patients with unilateral cleft lip and palate (UCLP) at two stages of skeletal maturation. Cone-beam computed tomography (CBCT) scans of 52 UCLP patients (34 prepubertal; 18 pubertal) were collected from an outpatient referral center for the treatment of craniofacial deformities. In total 15 multiplanar craniofacial landmarks were identified, 3D virtual surface models were created, and 13 variables were measured to assess the 3D Euclidean distances between landmarks and spatial position of the landmarks in the projected X, Y and Z components. Maxillary and mandibular pitch (clockwise, counterclockwise) rotation relative to the cranial base was also evaluated. The significance level was set at 5%. Maxillary retrusion value relative to the cranial base was higher and statistically significant greater (p = 0.028) in pubertal (SNA, 77.4° ± 6.2; N-ANS Y, 3.3 mm ± 3.1) than in prepubertal patients (SNA 81.0° ± 5.2; N-ANS Y, 5.8 mm ± 2.7). The posterior cranial base length (S-Ba Y) was significantly longer (p = 0.013) in pubertal (20.7 mm ± 3.4) than in prepubertal patients (18.4 mm ± 2.7). The upper facial height (N-ANS Z) was significantly greater (p = 0.01) in pubertal (46.9 mm ± 4.5) than in prepubertal patients (43.4 mm ± 3.0). Prepubertal and pubertal UCLP patients presented distinct patterns of craniofacial morphology, mainly in the sagittal component of the maxilla and in the posterior cranial base length. Pubertal patients had greater maxillary retrusion and posterior cranial base length.

Mechanical Properties of Mini-Implants Used in Extra-Radicular Anchorage

ABSTRACT Objective: To evaluate the mechanical properties of mini-implants (MIs) manufactured from stainless steel and compare them with conventional titanium-aluminum-vanadium alloy MIs. Material and Methods: The following groups were formed: G1 (n=24), 8×1.5 mm steel MIs; G2 (n=24), 12×2.0 mm steel MIs; and G3 (n=24), 10×1.5 mm titanium MIs. The 72 MIs were inserted in the infra zygomatic crest region of the maxilla and retromolar trigone in the jaw of 10 pigs. Pull-out, insertion torque, fracture and percussion tests were performed in order to measure the tensile strength, primary stability and fracture strength of MIs. A digital torque gauge was used to measure insertion and fracture torque, a universal mechanical testing machine was used for pull-out testing and a periotest device was used to measure the micromovement of MIs. For morphological and MI component evaluation, scanning electron microscopy (SEM) was performed. D'Agostino & Pearson, Kruskal-Wallis, and Dunn post-hoc and normality tests were used. Results: G2 insertion and fracture torques were significantly higher than G1 and G3 insertion and fracture torques (p<0.05). The pull-out and percussion tests presented similar values among the groups. SEM revealed that the fracture point was predominantly on the fourth thread for steel MIs (G1 and G2) and on the seventh thread for titanium-aluminum-vanadium MIs (G3). Conclusion: The mechanical properties of stainless steel MIs are superior to those of titanium-aluminum-vanadium alloy MIs.

Craniofacial morphology of patients with unilateral cleft lip and palate at two stages of skeletal maturation

Abstract The aim of this retrospective cross-sectional investigation was to perform a 3D analysis of craniofacial morphology of patients with unilateral cleft lip and palate (UCLP) at two stages of skeletal maturation. Cone-beam computed tomography (CBCT) scans of 52 UCLP patients (34 prepubertal; 18 pubertal) were collected from an outpatient referral center for the treatment of craniofacial deformities. In total 15 multiplanar craniofacial landmarks were identified, 3D virtual surface models were created, and 13 variables were measured to assess the 3D Euclidean distances between landmarks and spatial position of the landmarks in the projected X, Y and Z components. Maxillary and mandibular pitch (clockwise, counterclockwise) rotation relative to the cranial base was also evaluated. The significance level was set at 5%. Maxillary retrusion value relative to the cranial base was higher and statistically significant greater (p = 0.028) in pubertal (SNA, 77.4° ± 6.2; N-ANS Y, 3.3 mm ± 3.1) than in prepubertal patients (SNA 81.0° ± 5.2; N-ANS Y, 5.8 mm ± 2.7). The posterior cranial base length (S-Ba Y) was significantly longer (p = 0.013) in pubertal (20.7 mm ± 3.4) than in prepubertal patients (18.4 mm ± 2.7). The upper facial height (N-ANS Z) was significantly greater (p = 0.01) in pubertal (46.9 mm ± 4.5) than in prepubertal patients (43.4 mm ± 3.0). Prepubertal and pubertal UCLP patients presented distinct patterns of craniofacial morphology, mainly in the sagittal component of the maxilla and in the posterior cranial base length. Pubertal patients had greater maxillary retrusion and posterior cranial base length.

Does surgically assisted maxillary expansion improve obstructive sleep apnoea in adults? A systematic review and meta-analysis.

Introduction The aim of this systematic review and meta-analysis was to evaluate the effects of maxillary expansion on adults with obstructive sleep apnoea (OSA).Methods Electronic searches up to July 2021 in eight electronic databases were conducted. Study selection, data extraction, risk of bias evaluation using ROBINS-I, quality of evidence assessment using GRADE and meta-analyses were performed.Results The electronic searches yielded 1,007 studies. Following the application of the eligibility criteria, 15 articles were fully read and five studies were included. The studies evaluated the effects of surgically assisted rapid maxillary expansion in adults with OSA. The meta-analysis demonstrated an improvement in Apnoea-Hypopnea Index (AHI) (MD = -9.91, CI = -14.57 to -5.25), Oxygen Desaturation Index (ODI) (MD = -7.95, CI = -12.23 to -3.67), and Epworth Sleepiness Scale (ESS) (MD = -4.40, CI = -6.39 to -2.40). ROBINS-I indicated serious, no information and critical risk of bias for the included studies. The quality of the evidence was very low.Conclusion The findings herein suggest that maxillary expansion could improve OSA in adults in the short term.

Information and Communications Technology in Dentistry: an informative and educational approach for patients with fixed orthodontic appliances.

OBJECTIVE: To develop and make available, at no cost to the user, Information and Communications Technology (ICT) tools for Dentistry, providing dental information and advice geared toward patients undergoing orthodontic treatment with fixed appliances. MATERIAL AND METHODS: A Dentistry-based content that contemplated information and advice concerning orthodontic treatment with fixed appliances was elaborated. The materials, which included instructions on oral hygiene and treatment strategies when faced with possible complications, were evaluated and validated by specialists, whose assessments reached a 85% approval. From the validated content, products using four distinct ICT tools were formulated. RESULTS: The following technological products were developed: a program for community radios, three blog posts, four educational and informative videos, and a smartphone application - using texts, as well as images and videos. These ICT tools, geared toward patients wearing fixed orthodontic appliances, were made available by internet at no cost to the user, and the number of accesses is already expressive. CONCLUSION: These technological-scientific tools, developed and provided freely to the population, can aid patients during their treatment with fixed orthodontic appliances, contributing to the dissemination of reliable information, and clarifying doubts that may arise during orthodontic therapy. These free ICT tools serve to facilitate access to scientific knowledge, thereby favoring social inclusion, bearing in mind that this educational and informative material was offered in a simple and accessible manner to the general population.

Dehiscence and buccal bone thickness after rapid maxillary expansion in young patients with unilateral cleft lip and palate.

INTRODUCTION: The present study aimed to evaluate the consequences of rapid maxillary expansion in the buccal bone thickness and dehiscence of subjects with unilateral cleft lip and palate. METHODS: This prospective cohort study consisted of 30 participants, 20 males and 10 females, between 8 and 15 years old. Participants were allocated into 3 groups, according to the type of maxillary constriction, and were treated with different types of expanders: G1, hyrax; G2, fan-type; G3, inverted mini-hyrax. Cone-beam computed tomography scans were performed immediately before treatment and after 90 days of retention. Linear measurements were obtained by the same calibrated and blinded examiner. RESULTS: An average of 0.8 mm decrease in buccal bone thickness (P <0.001) and a 0.5 mm increase in dehiscence (P <0.001) were observed. There was no significant difference between the cleft and noncleft side for all variables (P >0.05), as there was no significant difference between groups (P >0.05). CONCLUSION: The findings in this study allow the conclusion that the orthopedic forces of rapid maxillary expansion lead to a decrease in the posterior buccal bone volume in unilateral cleft lip and palate patients.

Effectiveness of Chewing Gum Containing CPP-ACP for Remineralisation of Demineralised Enamel around Orthodontic Brackets: An in Situ Study

Abstract Objective: To evaluate the effectiveness of chewing gums containing CPP-ACP in remineralisation of demineralised enamel around orthodontic brackets. Material and Methods: Enamel blocks from 120 bovine incisors were used. The blocks were flattened and polished, followed by the development of incipient subsurface caries. The blocks have been subjected to a baseline microhardness analysis. Orthodontic brackets were bonded to the exposed area of the blocks, reserving an area for hardness analysis. An in situ crossover (three-way crossover phases of 21 days with an interval of one week between them), controlled, randomised and blind experimental model was used, with the participation of 12 volunteers divided into groups: G1 - negative control group, without chewing gum; G2 - conventional sugar-free chewing gum, without CPP-ACP (placebo); and G3 - sugar-free chewing gum with CPP-ACP. The following parameters were analysed: superficial linear (Ra), volumetric roughness (Sa), and superficial structural loss, which was indicated by Gap measurement (difference between the healthy and treated area). Statistical tests used were the Friedman, Wilcoxon and Shapiro-Wilk, Kruskal Wallis' nonparametric tests and ANOVA. Results: There was a significant reduction in enamel microhardness after demineralisation in all the groups (p<0.05). This deleterious effect was attenuated in the three groups after the final evaluation, although there were no statistical differences (p<0.05); however, the final values did not return to the baseline values (p<0.05). Conclusion: Chewing gum containing CPP-ACP did not promote in situ remineralisation of demineralised enamel around orthodontic brackets.

Information and Communications Technology in Dentistry: an informative and educational approach for patients with fixed orthodontic appliances

ABSTRACT Objective: To develop and make available, at no cost to the user, Information and Communications Technology (ICT) tools for Dentistry, providing dental information and advice geared toward patients undergoing orthodontic treatment with fixed appliances. Material and Methods: A Dentistry-based content that contemplated information and advice concerning orthodontic treatment with fixed appliances was elaborated. The materials, which included instructions on oral hygiene and treatment strategies when faced with possible complications, were evaluated and validated by specialists, whose assessments reached a 85% approval. From the validated content, products using four distinct ICT tools were formulated. Results: The following technological products were developed: a program for community radios, three blog posts, four educational and informative videos, and a smartphone application - using texts, as well as images and videos. These ICT tools, geared toward patients wearing fixed orthodontic appliances, were made available by internet at no cost to the user, and the number of accesses is already expressive. Conclusion: These technological-scientific tools, developed and provided freely to the population, can aid patients during their treatment with fixed orthodontic appliances, contributing to the dissemination of reliable information, and clarifying doubts that may arise during orthodontic therapy. These free ICT tools serve to facilitate access to scientific knowledge, thereby favoring social inclusion, bearing in mind that this educational and informative material was offered in a simple and accessible manner to the general population.

RESUMO Objetivos: Desenvolver e disponibilizar, gratuitamente, ferramentas de tecnologia da informação e comunicação (TIC) para a Odontologia, abordando informações e orientações direcionadas a pacientes em tratamento ortodôntico com aparelho fixo. Material e Métodos: Foi elaborado um conteúdo que contemplou informações e orientações concernentes ao tratamento ortodôntico com aparelho fixo. O material, que abrangeu instruções sobre higiene bucal e sobre abordagens diante de possíveis intercorrências, foi avaliado e validado por especialistas. A partir do conteúdo validado, foram elaborados produtos utilizando quatro ferramentas distintas de TIC. Resultados: Foram desenvolvidos os seguintes produtos tecnológicos: um programa para rádios comunitárias, três postagens para blog, quatro vídeos educacionais e informativos, e um aplicativo para smartphones, utilizando não apenas textos, mas também imagens e vídeos. Essas ferramentas de TIC direcionadas a pacientes fazendo uso de aparelho ortodôntico fixo foram disponibilizadas gratuitamente via internet, e já contam com expressivo número de acessos. Conclusões: As ferramentas técnico-científicas, desenvolvidas e fornecidas livremente à população, podem auxiliar pacientes durante o tratamento com aparelho ortodôntico fixo, contribuir para disseminar informações confiáveis e esclarecer dúvidas que surgem durante a terapia ortodôntica. Essas ferramentas gratuitas de TIC facilitam o acesso ao conhecimento científico e, consequentemente, favorecem a inserção social, tendo em vista que esse material educacional e informativo foi ofertado de maneira simples e acessível à população.

The effects of corticotomy and piezocision in orthodontic canine retraction: a randomized controlled clinical trial.

BACKGROUND: The aims of this study were to evaluate the efficacy of alveolar corticotomy (AC) and piezocision (PZ) in accelerating maxillary canine retraction, and their effects on multiple bone remodeling expression in gingival crevicular fluid (GCF). A split-mouth, randomized controlled clinical trial was performed at the Department of Orthodontics of Pontifical Catholic University of Minas Gerais, Brazil. Eligibility criteria included orthodontic need for first maxillary premolars extractions, followed by canine retraction. Fifty-one adult patients were recruited and randomly assigned to 3 groups (allocation ratio 1:1:1). Random allocation of surgical or control interventions to each side of the maxillary arch was also conducted: G1 - AC × Control, G2 - PZ × Control, and G3 - AC × PZ. Both the definition of the group and the decision of the experimental or control sides were randomized by the software. Intraoral digital scans were performed before, 7 and 14 days after the beginning of canine retraction, and subsequently, at every 14 days until a maximum period of 6 months. GCF samples were collected before, and 1, 2, 4, 8, and 12 weeks. The primary outcome consisted in the cumulative distal movement of the canines and was measured by digital model superimposition. The secondary outcome consisted in GCF bone remodeling samples that were quantified in a multiplex immunoassay. The measurements examinator was properly blinded. RESULTS: Forty-seven patients, 19 males and 28 females, were analyzed (mean age 20.72, SD = 6.66, range 15 to 38). Statistically significant differences in canine distal movement between AC and control in G1 were not observed (p > 0.05). In G2, PZ showed lower cumulative incisal and cervical measurements than control from the 2nd to the 24th week (p < 0.05). In G3, PZ showed a lower cumulative incisal and cervical measurements than AC from the16th to the 24th week (p < 0.05). In all groups, differences on biomarkers expression occurred at specific timepoints (p < 0.05), but a distinct pattern was not observed. CONCLUSIONS: AC and PZ were not effective to accelerate maxillary canine retraction and did not induce a distinct pattern of biomarker expression. TRIAL REGISTRATION: NCT03089996 . Registered 24 March 2017 - Registered.

Mini Hyrax vs Hyrax expanders in the rapid palatal expansion in adolescents with posterior crossbite: a randomized controlled clinical trial.

PURPOSE: The aim of this study was to compare the dental effects, impact on quality of life, and pain perception of adolescents wearing Mini Hyrax and Hyrax expanders in rapid palatal expansion. METHODS: Thirty-four adolescents aged 11 to 16 years, with maxillary transverse deficiency (unilateral or bilateral posterior crossbite), were randomly allocated into two groups, Mini Hyrax group and Hyrax group (1:1 ratio). Dental effects were evaluated by digitally superimposed pretreatment and postretention three-dimensional intraoral scans on the palatal rugaes using the software 3DSlicer. Impact on quality of life was assessed with the OHIP-14 questionnaire applied in the pretreatment, posttreatment and postretention. Visual analog scale was applied 24, 48, and 72 h and 7 days after the first activation of the expander. RESULTS: Thirty of the 34 adolescents recruited completed the study. There were no statistically significant differences in dentoalveolar effects between groups. OHIP-14 scores across time among Mini Hyrax wearers were similar to those of the Hyrax wearers. The inter-group comparisons showed no difference between groups with respect to the OHIP-14 scores in posttreatment and postretention (p > 0.05). There were no differences in pain perception between groups. Considering intra-group comparison, the reduction in pain perception among adolescents in the Mini Hyrax group was gradual. Among adolescents in the Hyrax group, a statistically significant reduction between 48 and 72 h was observed. CONCLUSION: There were no significant differences in dental effects, impact on quality of life and pain perception between adolescents wearing Mini Hyrax and Hyrax expanders in rapid palatal expansion.

Orthodontic retreatment: positive effects on the patient's self-esteem and quality of life.

INTRODUCTION: An increasing percentage of the world's population has had access to orthodontic treatment within the last few decades. Consequently, a larger number of patients seeking for correction of their malocclusions, nowadays, present with a history of previous orthodontic therapy. Orthodontists performing retreatments in their practice may have to face additional difficulties, and one of them is treating individuals that may be even more demanding for excellent results and efficient treatments. OBJECTIVES: This manuscript discusses the challenges faced when performing orthodontic retreatments. It illustrates a two-phase retreatment of a pre-adolescent and the ortho-surgical retreatment of a young adult with high demands for fast and exceptional results. Finally, this paper elaborates on the positive impacts that these retreatments had on the patients' self-esteem and quality of life.

Orthodontic retreatment: positive effects on the patient's self-esteem and quality of life

ABSTRACT Introduction: An increasing percentage of the world's population has had access to orthodontic treatment within the last few decades. Consequently, a larger number of patients seeking for correction of their malocclusions, nowadays, present with a history of previous orthodontic therapy. Orthodontists performing retreatments in their practice may have to face additional difficulties, and one of them is treating individuals that may be even more demanding for excellent results and efficient treatments. Objectives: This manuscript discusses the challenges faced when performing orthodontic retreatments. It illustrates a two-phase retreatment of a pre-adolescent and the ortho-surgical retreatment of a young adult with high demands for fast and exceptional results. Finally, this paper elaborates on the positive impacts that these retreatments had on the patients' self-esteem and quality of life.

RESUMO Introdução: Um percentual crescente da população mundial vem tendo acesso ao tratamento ortodôntico ao longo das últimas décadas. Consequentemente, hoje em dia, um maior número de pacientes em busca da correção de suas más oclusões apresenta um histórico de tratamento ortodôntico prévio. Ortodontistas que realizam retratamentos ortodônticos podem enfrentar dificuldades adicionais, e uma delas é ter que lidar com indivíduos que apresentam demandas e expectativas ainda maiores em relação à obtenção de resultados excelentes e de forma bastante eficiente. Objetivos: O presente artigo discute os desafios e os impactos positivos do retratamento ortodôntico causados na autoestima e na qualidade de vida dos pacientes, e ilustra o retratamento em duas fases de uma pré-adolescente, e o retratamento ortodôntico-cirúrgico de uma paciente adulta jovem que tinha demandas muito elevadas para a obtenção de resultados rápidos e excelentes.

Three-dimensional nasal septum and maxillary changes following rapid maxillary expansion in patients with cleft lip and palate.

OBJECTIVES: To determine the three-dimensional changes of the nasal septum (NS), alveolar width, alveolar cleft volume, and maxillary basal bone following rapid maxillary expansion (RME) in consecutive patients with unilateral cleft lip and palate (UCLP). MATERIALS AND METHODS: A retrospective investigation was conducted based on the analysis of cone-beam computed tomography (CBCT) data of 40 consecutive patients with UCLP (mean age 11.1 ± 2.2 years). Scans were acquired prior to RME (T0) and after removal of the expander (T1) before graft surgery. A three-dimensional analysis of the effects of RME on the nasal septum, alveolar width, alveolar cleft volume, and maxillary basal bone was performed. RESULTS: No changes in the NS deviation were observed following RME (P > .05). Significant increases of the alveolar transverse dimension were found in the anterior (14.2%; P < .001) and posterior (7.7%; P < .001) regions as well as in the volume of the alveolar cleft (19.6%; P < .001). No changes in the basal bone dimensions and morphology were observed (P > .05). CONCLUSIONS: Following RME, no changes were observed in the NS and maxillary basal bones of patients with UCLP despite the significant gain in the anterior and posterior alveolar width and the increase of the alveolar cleft defect. Clinicians should be aware that maxillary changes following RME in patients with UCLP are restricted to the dentoalveolar region.

Does dental trauma and its consequences influence the professional hiring process? Development, validation and application of an assessment tool.

OBJECTIVES: To develop and validate a questionnaire concerning the aspects evaluated during the hiring process by human resources professionals (HRPs); to apply the validated questionnaire; and to evaluate the perceptions and judgment of HRPs regarding different traumatic dental injuries (TDIs) and their consequences (TDI-Cs). MATERIALS AND METHODS: The acceptability, discriminative properties, internal consistency and test-retest reliability of the developed questionnaire were evaluated, using the same methodology as the main study and adopting a pilot sample. For both the validation process and the application phase, images of one male and one female were manipulated, or not (control), to create different types of TDI (enamel fracture, enamel and dentin fracture, avulsion) and TDI-Cs (crown discoloration, tooth loss due to avulsion). In the application phase, the images were analyzed by 100 HRPs using the validated questionnaire, and the results were analyzed using the Friedman, Wilcoxon and Mann-Whitney tests (P < 0.05). RESULTS: The developed questionnaire produced excellent acceptability, strong discriminative properties, satisfactory internal consistency and excellent to good test-retest reliability. The presence of TDIs and TDI-Cs had a negative effect on the evaluated aspects used during the hiring process (P < 0.001). Tooth loss provoked the worse level of judgment in all evaluated characteristics and in professional hiring. CONCLUSIONS: The developed questionnaire produced valid and reliable responses concerning the aspects evaluated during the hiring process by Brazilian HRPs. TDIs and TDI-Cs had a negative influence on the aspects evaluated during the HRP professional hiring process. CLINICAL SIGNIFICANCE: TDIs and TDI-Cs had a negative influence on the aspects evaluated during the HRP professional hiring process.

Viability of Maxillary Single Crowns Supported by 4-mm Short Implants: A Finite Element Study.

PURPOSE: Short implants are increasingly being used in posterior regions to avoid grafting procedures and their related risks, costs, and morbidity. However, studies focusing on implants measuring less than 6 mm long remain scarce, and the literature does not yet have a definition of the limits inherent with their use. This study attempts to investigate whether extra-short 4-mm implants are capable of receiving a maxillary single crown. MATERIALS AND METHODS: This study evaluates, through the finite element method, the stress distribution generated at implant lengths of 4 mm and 10 mm caused by different crown heights (10, 12.5, and 15 mm) in the posterior maxilla region when submitted to axial (200 N) and oblique (100 N) loads. RESULTS: The 4-mm implant showed a similar level of performance as that of the 10-mm implant when submitted to the axial load. However, the oblique load proved to be highly detrimental to both implants, inducing stresses of up to three times higher than those achieved in conjunction with the axial load, especially in the surrounding bone and the abutment. CONCLUSION: The use of 4-mm short implants to support single crowns in the posterior maxilla region may be feasible in habitual conditions; however, the risk associated with significant oblique loads should be mitigated by adopting a mutually protected occlusion approach and using acrylic occlusal devices if necessary.

Long-term stability of a Class III malocclusion with severe anterior open bite and bilateral posterior crossbite in a hyperdivergent patient.

Anterior open bite malocclusion is generally associated with several causes. This case report describes the 2-phase treatment of a 13-year-old boy with a Class III malocclusion, severe anterior open bite, and bilateral posterior crossbite treated without surgical intervention. An orthopedic approach was performed in phase 1 with a hyrax-type palatal expander, followed by maxillary protraction with a facemask for a 10-month period to promote the correction of transverse and sagittal deviations. In phase 2, a comprehensive orthodontic approach using fixed preadjusted appliances associated with intermaxillary elastics was performed. These approaches, combined with good patient compliance, established a functional and esthetic occlusal relationship, normal overjet and overbite, and a well-balanced facial appearance. The 4.5-year follow-up indicated that treatment results were stable.

Evaluation of Different Heights of Prosthetic Crowns Supported by an Ultra-Short Implant Using Three-Dimensional Finite Element Analysis.

PURPOSE: To apply finite element analysis (FEA) to investigate the stress distribution in a 4-mm-high ultrashort implant when supporting crowns of different heights in order to test the possibility of using this implant unitarily in the posterior edentulous mandible. MATERIALS AND METHODS: Three models of atrophic mandibles were created (M1, M2, and M3). Each model contained a 4-mm-length implant of a titanium-zirconium alloy, screw-type with internal connection, supporting nonsplinted screwed-in crowns of 10, 12.5, and 15 mm in height. Axial and oblique loads were simulated in the three model crowns. RESULTS: In an oblique load, the stress tended to be concentrated in the lingual region. In the qualitative results of the axial load, peaks of tension occurred in the lower angle between the inner groove and the inner conical portion of the implant. Regarding the differences in crown height, the 15-mm height produced a higher stress peak due to the lever effect of the crown under an oblique load. CONCLUSION: Within the limits of this study, the results suggest the possibility of using single crowns of proposed heights with unitary ultrashort implants installed in the posterior edentulous mandible, so long as there is no oblique load on the crown.

Bond Strength and Failure Pattern of Orthodontic Tubes Adhered to a Zirconia Surface Submitted to Different Modes of Application of a Ceramic Primer.

The aim of this study was to evaluate the shear bond strength of orthodontic tubes adhered to ceramics with the Transbond™ XT bonding resin (3M, Maplewood, MN, USA) while varying the surface treatment. Then, the adhesive remaining index (ARI) was verified, and the representative fracture patterns were evaluated via scanning electron microscopy. Forty-eight zirconia blocks were divided into three groups, varying the number of layers of the 10-methacryloyloxy-decyl dihydrogen phosphate (MDP) primer: one, two, or three applications. In addition, 16 lithium disilicate IPS E.max ceramic disks (Ivoclar Vivadent, Schaan, Liechtenstein) were conditioned with 10% hydrofluoric acid for 20 s and underwent a single-layer primer application regimen. The four groups were further stratified to undergo bond testing after either 24 h (control) or 5000 cycles in a thermocycling machine. A shear bond strength test was performed (0.5 mm/min), and the MPa values obtained were submitted to a two-way analysis of variance and Tukey's test. There was no statistical difference among the control group ceramics that received the varying surface treatments. After thermocycling, it was verified that both the E.max disks and the zirconia ceramics with three primer applications obtained the highest bond strength values. In the 24 h groups, a total displacement of the resin from the orthodontic tubes was observed (ARI of 1). After thermocycling, the highest prevalence of an ARI of 5 (adhesive failure) was observed among the zirconia ceramics with single-coat primer application, followed by those with triple-coat primer application (mixed failure). Three applications of the MDP-containing ceramic primer achieved the best result in the present study. Zirconia surface should be treated with three coats of MDP primer to achieve a level of bond strength similar to silica-rich phase ceramic.