Implant-supported canine retraction using different reactivation intervals of elastomeric chains: A CBCT-based split-mouth randomized controlled trial

ABSTRACT Introduction: Orthodontists attempt to maximize treatment efficiency regarding time, tooth position and adverse effects. A new approach, not yet explored, is the activation frequency. Objective: The aim of this split-mouth randomized controlled trial was to evaluate the effect of reactivation intervals on the efficiency of tooth movement. Methods: Thirty eight patients having a Class I malocclusion with bimaxillary dentoalveolar protrusion or severe crowding, Class II with mandibular deficiency or Class III, requiring first premolar extraction and canine retraction were recruited. Elastomeric chains producing 150g were replaced every two, four, six or eight weeks. There were 36, 37, 36, and 36 quadrants randomly allocated to these groups, respectively. The canine retraction rate was the primary outcome. Canine tipping, rotation, and root resorption and pain were the secondary outcomes. Only the outcome assessors were blinded to group assignment. Results: The average total movement for the 6 months was 5.14, 5.31, 2.79 and 3.85 mm for the two-week, four-week, six-week and eight-week reactivation intervals, respectively. Root resorption was significantly higher in the two-week and four-week groups. No adverse events were observed. Conclusion: The canine retraction rate, tipping, rotation and pain were similar in 2, 4, 6 and 8-week activation intervals groups. Longer reactivation intervals show less root resorption. The trial protocol was not pre-registered. The study was self-funded.

RESUMO Introdução: Os ortodontistas buscam otimizar a eficiência do tratamento quanto ao tempo de duração, à posição dos dentes e aos efeitos adversos. Um aspecto ainda não avaliado são os diferentes intervalos entre as ativações. Objetivo: O objetivo desse estudo controlado e randomizado de boca dividida foi avaliar a influência de diferentes intervalos de reativação na eficiência da movimentação dentária. Métodos: Foram recrutados 38 pacientes com má oclusão de Classe I com biprotrusão dentoalveolar ou apinhamento severo, Classe II com deficiência mandibular ou Classe III, que necessitavam de extração do primeiro pré-molar e retração do canino. As cadeias elastoméricas gerando 150 g foram substituídas a cada duas, quatro, seis ou oito semanas, constando 36, 37, 36 e 36 quadrantes alocados aleatoriamente nesses grupos, respectivamente. O desfecho primário foi a taxa de retração do canino. Os desfechos secundários foram a inclinação, a rotação e a reabsorção radicular do canino, e a dor. Somente os avaliadores dos resultados não tinham conhecimento da alocação nos grupos. Resultados: O movimento total médio para os seis meses foi de 5,14; 5,31; 2,79 e 3,85 mm para os intervalos de reativação de duas semanas, quatro semanas, seis semanas e oito semanas, respectivamente. A reabsorção radicular foi significativamente maior nos grupos de duas e quatro semanas. Não foram observados eventos adversos. Conclusão: A taxa de retração, a inclinação e a rotação do canino e a dor foram semelhantes nos grupos com intervalos de ativação de duas, quatro, seis e oito semanas. Intervalos de reativação mais longos mostram menos reabsorção radicular. O protocolo do estudo não foi pré-registrado. O estudo foi autofinanciado.

Does leukocyte-platelet-rich fibrin (L-PRF) cause long term acceleration in the rate of canine retraction? A split-mouth, two-arm parallel group, randomized control trial

ABSTRACT Objective: The present study was conducted to investigate the effects of leukocyte-platelet-rich fibrin (L-PRF) on the rate of maxillary canine retraction for a period of 5 months. Methods: A split-mouth study was conducted on 16 subjects (9 males and 7 females; age range 17-25 years; mean age, 21.85±2.45 years) who required therapeutic extraction of bilateral maxillary first premolars. After the initial leveling and alignment, L-PRF plugs were placed in a randomly selected extraction socket (Experimental Group), and the other side served as a control (Control Group). Canine retraction was carried out by the activation of nickel-titanium (NiTi) closed-coil springs delivering 150 g of force. The rates of canine movement, canine rotation, tipping, root resorption, and molar movement were assessed at monthly intervals for five months (T0-T5). Pain, swelling and discomfort accompanying the procedure were assessed using a Likert scale. Results: The study revealed a significant increase in the rate of canine movement on the experimental side in the first two months, and significant molar anchorage loss was observed only in the first month for control side. There were no statistically significant differences between the groups regarding canine rotation, tipping, probing depth, root resorption, and pain perception. Conclusions: The use of L-PRF plugs in extraction sockets considerably enhanced the rate of canine movement only in the first two months, and long-term efficacy was not observed in this study.

RESUMO Objetivo: O presente estudo foi realizado para investigar os efeitos da fibrina rica em leucócitos e plaquetas (L-PRF) na taxa de retração do canino superior, durante um período de cinco meses. Métodos: Um estudo de boca dividida foi realizado em 16 indivíduos (9 homens e 7 mulheres; faixa etária de 17 a 25 anos; idade média de 21,85 ± 2,45 anos) que precisavam de extração terapêutica dos primeiros pré-molares superiores de ambos os lados. Após o nivelamento e o alinhamento iniciais, os plugs de L-PRF foram colocados em um alvéolo pós-extração, selecionado aleatoriamente (Grupo Experimental), e o outro lado serviu como controle (Grupo Controle). A retração do canino foi realizada pela ativação de molas fechadas de níquel-titânio (NiTi) com 150 g de força. As taxas de movimentação do canino, rotação, inclinação e reabsorção radicular do canino e movimentação do molar foram avaliadas em intervalos mensais durante cinco meses (T0-T5). A dor, o inchaço e o desconforto após o procedimento foram avaliados por meio de uma escala de Likert. Resultados: O estudo revelou um aumento significativo na taxa de movimentação do canino no lado experimental nos dois primeiros meses, e uma perda significativa de ancoragem do molar foi observada apenas no primeiro mês no lado controle. Não houve diferenças estatisticamente significativas entre os grupos, com relação à percepção da dor e rotação, inclinação, profundidade de sondagem e reabsorção radicular do canino. Conclusões: O uso de plugs de L-PRF em alvéolos pós-extração aumentou consideravelmente a taxa de movimentação do canino apenas nos dois primeiros meses, não sendo observada uma eficácia em longo prazo.

Treatment of Class II division I malocclusion having severe crowding, proclination with noncomplaint fixed functional appliance therapy, and frictionless mechanics

Our Objective was to treat a patient having proclined, protruded teeth along with a Class II Skeletal malocclusion. 0.022 × 0.028 inch MBT Brackets were placed, and leveling alignment was commenced. Individual canine retraction was carried out in both arches, followed by retraction of the incisors in the upper arch with a Burrstone's T Loop. E2Z Forsus fatigue resistance appliance was given for the correction of Class II malocclusion. Proclination, protrusion, and crowding were corrected along with Class II Skeletal base. Individual canine retraction along with frictionless mechanics and noncompliant functional correction has sufficient potential to prevent anchor loss and correct a Class II skeletal base.

Comparative study of root resorption between two methods for accelerated orthodontic tooth movement

Objective: the aim of this study was to assess apical root resorption (RR) following the application of micro-osteoperforation (MOP) and piezocision (PzC) assisted orthodontics for the acceleration of tooth movement (TM). materials and methods: a total number of 16 patients seeking orthodontic therapy were included in this study. all patients had undergone 1st premolars extraction and were indicated for canine retraction. these patients were divided into two groups; one was treated using MOP in one side while the other side served as control. in the other group PzC was performed in one side with no intervention done on the other side. cone-beam computed tomography (CBCT) scans were obtained for every patient before and after canine retraction in order to evaluate amount of RR. results: in the MOP group, there was no significant difference in canine root length between experimental and control sides. whereas, in the PzC group, there was a statistically significant decrease in root length in the experimental side compared with the control side. when comparing both groups, the experimental PzC side showed a statistically significant decrease in root length compared to experimental MOP side postoperatively. conclusion: experimental PzC showed statistically significant decreases in canine root length compared to both experimental MOP and control side after canine retraction.

Distraction Osteogenesis - A Review.

Distraction osteogenesis (DO) one of the recent and most successful treatment option for various skeletal deformities. Initially it was mainly used for correction of axial skeleton, but its introduction to the craniofacial skeleton has revolutionized the mode of treatment of craniofacial deformities and congenital syndromes. Currently DO in dentistry have a wide range application starting from, rapid canine retraction, alveolar distraction, treatment of cleft palate, and correction of many mandibular disorders.

Effect of prostaglandin E1 versus corticotomy on orthodontic tooth movement: An in vivo study.

Background and Aim: The aim of the present study is to compare the effect of corticotomy versus prostaglandin E1 injection in human subjects on rate of tooth movement, anchorage loss and their effect on crest bone height and root length. Settings and Design: Clinical interventional study. Split mouth design was used. Materials and Methods: Study was done on 32 regular orthodontic patients. A volume of 100 mcg of prostaglandin E1 was injected on the right side once in 2 weeks and on the left side corticotomy was performed, and canine retraction was started on both sides simultaneously. The rate of space closure and anchorage loss was assessed with casts. The root length and crestal bone height changes were assed with IOPAs. The comparison of rate of tooth movement, anchorage loss, crestal bone height and root length changes between the sides were statistically analyzed using paired t‑test. Results: The average rate of space closure on right side was 0.36 mm/week with a standard deviation of 0.05 mm/week and on the left side average rate of space closure was 0.40 mm/week with a standard deviation of 0.04 mm/week. The difference between the rate of closure between the right side and left where found to be statistically significant (P = 0.003). The anchorage loss, the crestal bone height changes and root length changes were not statistically significant. Conclusion: The rate of tooth movement was significantly more with corticotomies when compared with given dose of prostaglandin injection.

The effects of electrical current from a micro-electrical device on tooth movement / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to determine whether an exogenous electric current to the alveolar bone surrounding a tooth being orthodontically treated can enhance tooth movement in human and to verify the effect of electric currents on tooth movement in a clinical aspect. METHODS: This study was performed on 7 female orthodontic patients. The electric appliance was set in the maxilla to provide a direct electric current of 20 micronA. The maxillary canine on one side was assigned as the experimental side, and the other as control. The experimental canine was provided with orthodontic force and electric current. The control side was given orthodontic force only. Electrical current was applied to experimental canines for 5 hours a day. The amount of canine movement was measured with an electronic caliper every week. RESULTS: The amount of orthodontic tooth movement in the experimental side during 4 weeks was greater by 30% compared to that of the control side. The amount of increase in tooth movement in the experimental side was statistically significant. The amount of tooth movement in the experimental side during the first two weeks was greater than that in the following two weeks. The amount of weekly tooth movement in the control side was decreased gradually. CONCLUSIONS: These results suggested that the exogenous electric current from the miniature electric device might accelerate orthodontic tooth movement by one third and have the potential to reduce orthodontic treatment duration.

Fricción durante la retracción de caninos en ortodoncia: revisión de literatura / Friction during canine retraction in orthodontics: literature review

La ortodoncia no es ajena a la rápida implementación clínica de nuevas alternativas debiomateriales, aunque este hecho demuestra un vibrante trabajo por mejorar las condiciones delos pacientes, en algunas ocasiones solo es explicable por decisiones de mercado impuestas porlas multinacionales. Los cambios más notables incluyen nuevos sistemas de adhesión de brackets,polímeros para ligado y nuevas combinaciones de materiales en el sistema bracket/alambre quebuscan una menor fricción. El propósito de esta revisión es presentar el comportamiento friccionalde diferentes aleaciones de brackets y alambres con o sin recubrimiento usados en ortodonciay su influencia durante la retracción de caninos al usar la técnica friccional. Como conclusióngeneral se encontró que el arco de alambre a escoger en la técnica friccional para la retraccióndebe ser el que produzca la menor fricción y mayor control del diente durante el movimiento,siendo la opción indicada los arcos cuadrados o rectangulares que no llenen totalmente la ranuradel bracket...

The purpose of this literature review was to present the frictional behavior of different alloys frombrackets and wives with and without covering and their effect on canine retraction when usingthe frictional technique. In conclusion it is suggested that arch mires selected for retraction withthe frictional technique should produce the smallest friction and have the longest control of toothmovement such as a square and rectangular arches which do not fill the bracket slot completely.

Rapid canine retraction in a Class II bialveolar protrusion case using a lingually extended distraction screw / 대한치과교정학회지

Rapid canine retraction, first introduced by Liou, is a distraction osteogenesis applied to the periodontal ligament tissue. Rapid tooth movement was facilitated by establishing minimal bony resistance on the distal surface of the canine by socket preparation and by osteogenesis on the mesial side in response to the periodontal distraction. Since undesired buccal tipping or extrusion of the canine during retraction tends to occur, it is crucial to maintain the firm path of movement and the axis of the canine during retraction. In order to improve the predictability of the canine movement, lingually extended distraction screws with heavy labial guiding wires were designed. Prefabricated plastic canine models for the estimation of socket depth and miniscrew implants for anchorage reinforcement were also devised. Applying these devices to a female patient with Class II anterior protrusion, the whole treatment was effectively finished in 13 months. Loss of vitality or periodontal problems did not occur throughout treatment, and stable occlusion was maintained during 10 months of retention. This case report demonstrates that a predictable rapid canine retraction can be achieved through the use of this modified technique.

Use of corticotomy for canine and molar retraction / 대한치과교정학회지

Tooth movement facilitated by corticotomy and distraction osteogenesis was discussed. In this study, a portion of cortical bone which can provide resistance to tooth movement in alveolar bone was removed. Active bone deposition was then possible in the tension side. Teeth moved at such a speedy rate as we could not imagine from conventional orthodontic treatment, which lead to the reduction of the total treatment period. Posterior movement of the canine or molar teeth was possible without any side effects such as anchorage loss, root resorption or periodontal breakdown.

A comparison of en masse retraction of six anterior teeth with separate canine retraction / 대한치과교정학회지

The purpose of this study was to compare en masse retraction of six anterior teeth with separate canine retraction in the amount of the anchorage loss and the retraction of the anterior teeth. The subjects consisted of 30 adult female patients with Angle Class I malocclusions who were treated by .022" straight wire appliance with 4 first premolar extraction. They were composed of two groups. Group 1 consisted of 15 subjects, whose six anterior teeth were retracted by en masse retraction. Group 2 consisted of 15 subjects, whose canines were retracted separately. Pre-treatment and post-treatment lateral cephalometric radiographs were analyzed. All data were processed statistically with independent samples t-test, and the conclusions were as follows. 1. There was no significant difference in the amount of the anchorage loss between two groups(p>0.05). 2. There was no significant difference in the amount of the retraction of the anterior teeth between two groups(p>0.05). 3. There was a significant difference in the amount of the inclinational change of the upper incisors between two groups. It was greater in Group 2. 4. There was a significant difference in the vertical positional change of the upper incisal edges between two groups. The upper incisal edges in Group 2 were more extruded than Group 1 by about 1 mm. 5. There was no significant difference in the vertical positional change of the root apex of the upper incisors between two groups(p>0.05). And there was no significant difference in the vertical positional change of the upper molar(p>0.05).

A photoelastic study of the stress distribution on canine retraction by segmented TMA T-loop spring / 대한치과교정학회지

The segmented TMA T-loop spring, used for reciprocal space closure and described by Burstone, was used to achievebodily movement of canine. Photoelastic analysis is a technique for the transformation of internal stress into visible light patterns. The two-dimensional photoelastic stress analysis was performed, and stress distribution was recorded by photography. The purpose of this study was to visualize photoelastically the distribution of forces transmitted to the alveolus and surrounding structures using new segmented TMA T-loop spring for canine retraction. The results were as follows: 1. Decreased activation produced decreased stress of upper 1st. premolar extraction site and increased intrusive stress of upper 1st. molar, regardless of T-loop position. 2. At 5mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site. 3. At 3mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site and mesial lower half of upper 1st. molar mesio-buccal root. 4. At 1mm activation, More anterior positioning of T-loop produced an increased stress in upper mesial and blew apex area of upper canine root. 5. 0.25 B/L ratio and 3mm activation produced bodily movement of canine. To summarize, desired tooth movement and anchorage requirement is possible by altering the activation and mesio-distal position of the T-loop spring.