Survival rate and stability of surface-treated and non-surface-treated orthodontic mini-implants: a randomized clinical trial

ABSTRACT Objectives: This clinical trial was conducted to evaluate the stability and failure rate of surface-treated orthodontic mini-implants and determine whether they differ from those of non-surface-treated orthodontic mini-implants. Trial Design: Randomized clinical trial with a split-mouth study design. Setting: Department of Orthodontics, SRM Dental College, Chennai. Participants: Patients who required orthodontic mini-implants for anterior retraction in both arches. Methods: Self-drilling, tapered, titanium orthodontic mini-implants with and without surface treatment were placed in each patient following a split-mouth design. The maximum insertion and removal torques were measured for each implant using a digital torque driver. The failure rates were calculated for each type of mini-implant. Results: The mean maximum insertion torque was 17.9 ± 5.6 Ncm for surface-treated mini-implants and 16.4 ± 9.0 Ncm for non-surface-treated mini-implants. The mean maximum removal torque was 8.1 ± 2.9 Ncm for surface-treated mini-implants and 3.3 ± 1.9 Ncm for non-surface-treated mini-implants. Among the failed implants, 71.4% were non-surface-treated mini-implants and 28.6% were surface-treated mini-implants. Conclusion: The insertion torque and failure rate did not differ significantly between the groups, whereas the removal torque was significantly higher in the surface-treated group. Thus, surface treatment using sandblasting and acid etching may improve the secondary stability of self-drilling orthodontic mini-implants. Trial registration: The trial was registered in the Clinical Trials Registry, India (ICMR NIMS). Registration number: CTRI/2019/10/021718

RESUMO Objetivos: Este ensaio clínico foi conduzido para avaliar a estabilidade e a taxa de falha de mini-implantes ortodônticos com superfície tratada, e determinar se elas diferem das dos mini-implantes ortodônticos sem superfície tratada. Desenho do estudo: Ensaio clínico randomizado com desenho de boca dividida. Instituição: Department of Orthodontics, SRM Dental College, Chennai/India. Participantes: Pacientes que necessitavam de mini-implantes ortodônticos para retração anterior em ambas as arcadas. Métodos: Mini-implantes ortodônticos autoperfurantes, cônicos, de titânio com ou sem tratamento de superfície, foram colocados em cada paciente, seguindo um desenho de boca dividida. Os torques máximos de inserção e de remoção foram medidos para cada mini-implante, usando um torquímetro digital. As taxas de falha foram calculadas para cada tipo de mini-implante. Resultados: O valor médio do torque máximo de inserção foi de 17,9 ± 5,6 Ncm para mini-implantes com superfície tratada e 16,4 ± 9,0 Ncm para mini-implantes sem superfície tratada. O valor médio do torque máximo de remoção foi de 8,1 ± 2,9 Ncm para mini-implantes com superfície tratada e 3,3 ± 1,9 Ncm para mini-implantes sem superfície tratada. Entre os implantes que falharam, 71,4% eram mini-implantes sem superfície tratada e 28,6% eram mini-implantes com superfície tratada. Conclusão: O torque de inserção e a taxa de falha não diferiram significativamente entre os grupos; porém, o torque de remoção foi significativamente maior no grupo com superfície tratada. Assim, o tratamento de superfície com jateamento e condicionamento ácido pode melhorar a estabilidade secundária dos mini-implantes ortodônticos autoperfurantes. Registro do estudo: Esse estudo foi registrado no Clinical Trials Registry, Índia (ICMR NIMS). Número de registro: CTRI/2019/10/021718

Twist removal of healed vs. nonhealed implants-a mechanical and histological study in mini pigs.

PURPOSE: The objective of this study was to evaluate the effect of removal torque (reverse torque) of titanium implants in peri-implant bone. METHODS: The P1-M1 teeth were extracted bilaterally of 6 mini pigs (BR-1). Each animal received 6 titanium implants, three for each side of mandible. On the right side of mandible, 3 implants reminded 9 months (9M) under masticatory activity and on the left side, other 3 implants were placed and immediately removed (IR). All 36 implants were removed by removal torque, and the recorded values were statistically analyzed. Animals were euthanized right after the removal torque and recording. Each third (cervical, medium, and apical) of peri-implant bone was extracted and analyzed histological and immunohistochemically. Student's t test was used to determine statistical differences in the values between the 9M and IR samples. Data were presented as means with standard deviations. The level of significance was set at 5% (P < 0.05). RESULTS: Removal torque was higher in 9M experimental situation than in IR. Histological characteristics of mature bone were presented in the 9M experimental condition, and immature bone characteristics were presented in the IR experimental condition. Removal torque caused small fractures and rounding in the bone grooving. Immunohistochemical analysis reinforced the histological results; Student's t test provided statistically significant differences to osteocalcin expression in 9M samples and no statistically significant differences expression to collagen I in both experimental conditions (P < 0.05). CONCLUSIONS: Removal torque caused microscopical fractures and smoothing in the peri-implant bone grooves, but it does not compromise the bone healing.

Effects of a Low-Intensity Laser on Dental Implant Osseointegration: Removal Torque and Resonance Frequency Analysis in Rabbits.

The objective of this study was to investigate how a low-intensity laser affects the stability and reverse torque resistance of dental implants installed in the tibia of rabbits. Thirty rabbits received 60 dental implants with the same design and surface treatment, one in each proximal metaphysis of the tibia. Three groups were prepared (n = 10 animals each): conventional osseointegration without treatment (control group), surgical sites irradiated with a laser beam emitted in the visible range of 680 nm (Lg1 group), surgical sites irradiated with a laser beam with a wavelength in the infrared range of 830 nm (Lg2 group). Ten irradiation sessions were performed 48 hours apart; the first session was during the immediate postoperative period. Irradiation energy density was 4 J/cm(2) per point in 2 points on each side of the tibias. The resonance frequency and removal torque values were measured at 2 time points after the implantations (3 and 6 weeks). Both laser groups (Lg1 and Lg2) presented a significant difference between resonance frequency analysis values at the baseline and the values obtained after 3 and 6 weeks (P > .05). Although the removal torque values of all groups increased after 6 weeks (P < .05), both laser groups presented greater mean values than those of the control group (P < .01). Photobiomodulation using laser irradiation with wavelengths of 680 and 830 nm had a better degree of bone integration than the control group after 6 weeks of observation time.

Evaluation of removal torque values for titanium screws of prosthetic abutments after different torque application techniques: in vitro study / Avaliação dos valores de torque de remoção para parafusos de titânio de abutments protéticos após aplicação de diferentes técnicas de torque: estudo in vitro

Objetivo: Avaliar os valores de torque de remoção em abutments parafusados após aplicação de diferentes técnicas de torque. Materiais e Métodos: Trinta espécimes de implante hexágono externo, abutment pré-fabricado e parafuso de titânio foram distribuídos randomicamente em três grupos. No grupo 1, os parafusos receberam um torque de 30 N.cm; no grupo 2 receberam um torque de 30N.cm e um segundo torque após 10 min, de acordocom a técnica proposta por Brending et al. e Dixon et al.; no grupo 3, um torque de 30 N.cm foi aplicado e mantido por 20 s, de acordo com a técnica recomendada por Sella et al. Os espécimes foram inseridos na máquina de teste universal e uma chave digital foi acoplada a célula de carga para controlar o valor de torque e a velocidade de 1N.cm/s. O torque de remoção foi realizado 10 min após o torque de aplicação. Os valores foramestatisticamente analisados usando 1-way ANOVA e Tukey HSD test (α = 0,05). Resultados: As médias e desvio padrão (±SD) dos valores de torque deremoção encontrados foram 27,95 ± 0,99N.cm para o grupo 1; 28,32 ± 0,68N.cm para o grupo 2 e 26,89 ± 1,03 N.cm para o grupo 3. Os grupos 1e 2 exibiram valores estatisticamente mais altos de torque quando comparados ao grupo 3 (p < 0,05).Conclusão: A técnica recomendada por Breeding et al. e Dixon et al. pareceu ser a melhor opção quando considerado os valores do torque de remoção de implantes hexágono externo.

Objective: To evaluate the removal torque values on abutment screws after different torque application techniques. Materials and Methods: Thirty specimens of an external hexagon implant, a prefabricated abutment and a titanium screw were distributed randomly in three groups. In group 1, the screws received a torque of 30N.cm; group 2 received a torque of 30N.cm and a second torque after 10 min, in accordance with the technique proposed by Brending et al. and Dixon et al.; in group 3, a torque of 30 N.cm was applied and maintained for 20 s, in accordance with the technique recommended by Sella et al. The specimens were attached to a universaltesting machine and a digital key was coupled to the load cell in order to control the torque value at a velocity of 1 N.cm/s. Removal torque was performed 10 minutes after torque application. Values were statistically analysed using one-way ANOVA and Tukey’s HSD test (α = 0.05). Results:The mean and standard deviations (±SD) of removal torque values found were 27.95 ± 0.99N.cm for group 1, 28.32 ± 0.68N.cm for group 2 and 26.89±1.03N.cm for group 3. Groups 1 and 2 exhibited statistically higher values of torque than group 3 (p < 0.05). Conclusion: The techniquerecommended by Breeding et al. and Dixon et al. seemed to be the best option when considering the removal torque values of external hexagonimplants

The Influence of Low-Level Laser on Osseointegration Around Machined and Sandblasted Acid-Etched Implants: A Removal Torque and Histomorphometric Analyses.

Evaluation of the influence of laser application on osseointegration around implants with different surface characteristics is limited. This study aims to evaluate the influence of low-level lasers on the early stages of osseointegration. Ninety-six external hex implants (3.75 mm × 5.0 mm) were placed in 24 rabbits-one machined and one sandblasted acid-etched per tibia. The rabbits were later divided into the laser group, which received a total dose of 24 J/cm(2) of gallium-aluminum-arsenide laser over 15 days, and a control group. At 16 and 30 days after surgery, removal torque and histomorphometric analyses were performed. No statistical differences in removal torque or histomorphometric analyses were verified between laser and control groups regardless of implant surface (P > .05). Time was the only variable presenting significant differences between measurements (P < .05). Low-level laser had no significant short-term effect on bone-to-implant contact and removal torque values regardless of implant surface characteristics.

Torque de retiro de implantes de titanio instalados en tibia de perros con defecto óseo / The Removal torque of titanium implant inserted in dog tibia with a bone defect

El torque de remoción es utilizado para estudiar el comportamiento de implantes y su oseointegración. El objetivo de esta investigación fue determinar el torque de retiro de implantes dentales con defectos óseo asociados de tipo fenestración. Seis perros (Canis familiaris) fueron en semejantes condiciones de peso y talla seleccionados para la investigación. Se realizó un acceso quirúrgico al fémur del animal sitio donde se instalaron 3 implantes, realizándose defectos circulares de 5mm en cada implante. El defecto fue cubierto con membrana absorbible (colágeno), membrana no absorbible (celulosa) o sin cobertura (control). Los animales fueron sometidos a eutanasia a las 3 semanas y a los 8 semanas, momento en que se les realizó el torque de retiro a los implantes con una llave especialmente diseñada para el procedimiento; el análisis de datos se realizó con la prueba de Turkey con significancia estadística p<0.1. Se observó una creciente reparación ósea en los diferentes tiempos de eutanasia; el defecto control reveló un menor nivel de reparación al ser comparado con los defectos cubiertos por membranas. Se realizó el torque de retiro en los implantes estableciendo valores crecientes de unión hueso-implante en los tiempos de eutanasia. No existió diferencias significativas en los torques de retiro de los implantes en ninguno de los defectos generados. Finalmente se puede concluir que las membranas biológicas y la reparación no influyó en el torque de retiro de implantes dentales.

The removal torque has been used for analysis of implant and their osseointegration. The aim of this research was to determine the removal torque of dental implants installed with fenestration-type bone defect. Six dogs with similar conditions of weight and height were selected for this research. We realized a surgical approach to the tibia and in place installed 3 dental implants with 5 mm- diameter circular bone defect in each implant. The bone defects were covered with absorbable membrane (collagen), non absorbable membrane (cellulose) and one (control) defect without coverage. The animals were euthanized at three weeks and at eight weeks when torque withdrawal of the implant was realized with a ratchet especially designed for this procedure. Data analyses was realized with Turkey test with statistical significance of p<0.1. We observed an increasing bone repair for the two periods of euthanasia; the control defect show minor level of reparation when compared to defect coverage for membrane. We realized the removal torque with increasing values of bone-implant union for two periods of euthanasia. No difference was observed in removal torque in either defect with or without membrane. Finally, we conclude that biological membrane and bone repair was not influenced in the removal torque of dental implants.

Influência da velocidade no torque de remoção de tampas plásticas rosqueáveis para produtos farmacêuticos / Influence of the speed on the removal torque of plastic screw caps for pharmaceutical products

O estudo teve por objetivo avaliar a influência da velocidade empregada durante a determinação do torque de aplicação e remoção de tampas plásticas rosqueáveis de polipropileno (PP), com vedante interno, aplicadas em frascos de vidro e de poli(tereftalato de etileno) (PET) para produtos farmacêuticos, com diâmetros de terminação de 24 e 28 mm. Foi verificada também a influência do material de embalagem (vidro ou PET) e do diâmetro da terminação no torque de retenção estático e dinâmico (após simulação de transporte) em intervalos de tempo após 24 e 48 horas e após 7, 14 e 28 dias da aplicação dos respectivos sistemas de fechamento. Verificou-se que a velocidade não apresenta influência no torque de aplicação desde que o valor máximo seja controlado durante o processo de fechamento da tampa. No torque de remoção imediato, entretanto, a velocidade influencia significativamente nos resultados, sendo recomendado, sempre que possível, a utilização de uma velocidade constante. Foi estabelecido para o estudo a velocidade de 5 rpm para evitar a influência desse parâmetro nos resultados de torque obtidos. O material de embalagem e o diâmetro da terminação evidenciaram influência significativa nos resultados de torque de retenção estático e dinâmico, sendo observados valores superiores para os frascos de vidro comparativamente aos frascos de PET. Esse desempenho pode estar associado às diferenças nas propriedades viscoelásticas e na força de fricção ou atrito entre os materiais da tampa com vedante e a embalagem.

The objective of this study was to ascertain the influence on the measured torque of the speed employed during the tightening and removal of polypropylene (PP) screw caps, with internal liners, used on glass and polyethylene terephthalate (PET) bottles for pharmaceutical products, with mouth diameters of 24 and 28 mm. The influence of the packaging material (glass or PET) and mouth diameter on the static and dynamic torque retention was observed (after transport simulation) at time intervals after 24 and 48 hours and after 7, 14 and 28 days of torque application to each closure system. It was found that the speed did not influence the tightening torque since the torque is controlled during the closing process. However, the speed significantly influenced the immediate removal torque and it is preferable to use a constant speed whenever possible. It was found that a speed of 5 rpm was best, to prevent this parameter affecting the torque results. The packaging material and mouth diameter exerted a significant influence on the retention torque, both in the static and dynamic tests, and higher torques were observed for glass than for PET bottles. This performance may be related to viscoelastic properties and the friction between the lined cap and the packaging material.

The effect of laser on the stimulation of bone-implant interaction: an experimental study in rabbits / Efeito do laser na estimulação da interação osso-implante: um estudo experimental em coelhos

PURPOSE: To assess osseointegration by measuring the removal torque of smooth cylindrical implants placed in rabbit tibiae, having been subjected, or not, to low-intensity laser irradiation (GaAlAs). METHODS: Two implants were inserted into one tibiae of 16 male New Zealand rabbits weighing 3.5-4.0 kg; the animals were divided into four groups (control and laser at 16 and 30 days of wound healing). In the irradiated groups, laser was applied at a 830-nm wavelength, in continuous mode and with 100 mW of potency, and the applications were punctual, with 1 J/cm³ on three points, and were repeated eight times at 48-hour intervals starting immediately after implantation surgery, thus totaling 24 J/cm². After the wounds healed, the animals were sacrificed, the tibiae were removed, implant removal torques were measured by means of a handheld digital torque-meter, and a factorial variance analysis statistical test was applied. RESULTS: There was significant intergroup difference regarding time as a single factor. The removal torque observed in the control groups was, for smooth implants, 20.42±3.06 N/cm at 16 days and 27.42±19.65 N/cm at 30 days; in the irradiated groups, the removal torque for smooth implants was 19.15±4.65 N/cm at 16 days and 30.08±4.14 N/cm at 30 days. CONCLUSION: Removal torque values were higher at 30 days than at 16 days, independent of laser application.

OBJETIVO: Avaliar a osseointegração através do torque de remoção de implantes cilíndricos lisos, colocados em tíbias de coelhos, submetidos ou não à irradiação com laser de baixa intensidade (AsGaAl). METODOLOGIA: Foram utilizados 16 coelhos machos da raça Nova Zelândia, pesando entre 3,5 a 4,0 quilos, sendo inseridos dois implantes em uma tíbia, dividida em quatro grupos (controle e laser para 16 e 30 dias de cicatrização). No grupo irradiado foi aplicado laser com comprimento de onda de 830 nm, modo contínuo e potência de 100 mW, sendo a aplicação pontual de 1 J/cm² em três pontos e oito aplicações, com intervalo de 48 horas, iniciada imediatamente após a cirurgia de colocação dos implantes, perfazendo um total de 24 J/cm². Após o período de cicatrização, os animais foram sacrificados, e então, realizada a remoção das tíbias e, em seguida, a medição dos torques para remoção dos implantes com torquímetro digital manual, aplicando-se o teste estatístico de Análise de Variância Fatorial. RESULTADOS: Foi verificado que existe diferença significativa intra-grupos em relação ao fator isolado tempo. O torque de remoção obtido para o grupo controle: Implantes lisos com 16 dias (20,42±3,06 N/cm) e 30 dias (27,42±19,65 N/cm); e para o grupo irradiado: Implantes lisos com 16 dias (19,15±4,65 N/cm) e 30 dias (30,08±4,14 N/cm). CONCLUSÃO: Os valores do torque de remoção no período de 30 dias são superiores ao período de 16 dias, independentemente da aplicação de laser.