Comparison of the accuracy of two techniques for three-dimensional digital indirect bonding of orthodontic brackets: A randomized controlled trial.

OBJECTIVE: This study aimed to clinically compare the accuracy of bracket positioning between three-dimensionally (3D) printed indirect bonding trays and vacuum-formed trays made over 3D-printed models. MATERIAL AND METHODS: Fourteen patients, planned for fixed orthodontic therapy, were randomly divided into two equal groups. For both groups, both dental arches were scanned, to acquire virtual models, brackets were virtually positioned from central incisors to second premolars, and scans for the final bracket positions were performed. In the first group, transfer trays were 3D-printed. In the second group, virtual models were 3D-printed, and vacuum-formed soft sheets were thermoformed on the printed model. Teeth were indirectly bonded and then scanned. Superimposition of the virtual and the final bracket positioning scans was performed to measure linear and angular deviations in brackets positions. RESULTS: The first group showed significantly less occlusogingival and buccolingual linear errors than the second group. No significant differences in angular deviations were found between both groups. The frequencies of clinically acceptable linear errors within 0.5 mm and angular errors within 2° showed no statistically significant difference between both groups (p> 0.05 for all measurements). The transfer errors in both groups showed linear directional biases toward the mesial, gingival and labial directions. There was no statistically significant difference in the rate of immediate debonding between both groups (10.7% and 7.1% for the first and the second groups, respectively, p=0.295). CONCLUSIONS: 3D-printed indirect bonding trays were more accurate than vacuum-formed trays, in terms of linear deviations. Both types of trays showed similar angular control.

Comparison of the accuracy of two techniques for three-dimensional digital indirect bonding of orthodontic brackets: A randomized controlled trial

ABSTRACT Objective: This study aimed to clinically compare the accuracy of bracket positioning between three-dimensionally (3D) printed indirect bonding trays and vacuum-formed trays made over 3D-printed models. Material and Methods: Fourteen patients, planned for fixed orthodontic therapy, were randomly divided into two equal groups. For both groups, both dental arches were scanned, to acquire virtual models, brackets were virtually positioned from central incisors to second premolars, and scans for the final bracket positions were performed. In the first group, transfer trays were 3D-printed. In the second group, virtual models were 3D-printed, and vacuum-formed soft sheets were thermoformed on the printed model. Teeth were indirectly bonded and then scanned. Superimposition of the virtual and the final bracket positioning scans was performed to measure linear and angular deviations in brackets positions. Results: The first group showed significantly less occlusogingival and buccolingual linear errors than the second group. No significant differences in angular deviations were found between both groups. The frequencies of clinically acceptable linear errors within 0.5 mm and angular errors within 2° showed no statistically significant difference between both groups (p> 0.05 for all measurements). The transfer errors in both groups showed linear directional biases toward the mesial, gingival and labial directions. There was no statistically significant difference in the rate of immediate debonding between both groups (10.7% and 7.1% for the first and the second groups, respectively, p=0.295). Conclusions: 3D-printed indirect bonding trays were more accurate than vacuum-formed trays, in terms of linear deviations. Both types of trays showed similar angular control.

RESUMO Objetivo: Esse estudo teve como objetivo comparar clinicamente a precisão no posicionamento de braquetes usando guias de colagem indireta impressas tridimensionalmente (3D) e guias termoformadas a vácuo em cima de modelos impressos em 3D. Material e Métodos: Quatorze pacientes, planejados para tratamento ortodôntico fixo, foram divididos aleatoriamente em dois grupos de igual tamanho. Em ambos os grupos, as duas arcadas dentárias foram escaneadas para a criação dos modelos virtuais, os braquetes foram posicionados virtualmente dos incisivos centrais aos segundos pré-molares, e foram feitos os escaneamentos das posições finais dos braquetes. No primeiro grupo, as guias de transferência foram impressas em 3D. No segundo grupo, os modelos virtuais foram impressos em 3D e as guias foram termoformadas a vácuo em cima dos modelos impressos. Os braquetes foram colados de forma indireta e depois feitos os escaneamentos. Uma sobreposição das posições planejadas virtualmente e do escaneamento com os braquetes na posição final foi realizada para medir os desvios lineares e angulares nas posições dos braquetes. Resultados: O primeiro grupo apresentou significativamente menos erros lineares oclusogengivais e vestibulolinguais do que o segundo grupo. Não foram encontradas diferenças significativas nos desvios angulares entre os dois grupos. As frequências de erros lineares clinicamente aceitáveis menores que 0,5 mm e de erros angulares menores que 2° não apresentaram diferença estatisticamente significativa entre os dois grupos (p > 0,05 para todas as medições). Os erros de transferência em ambos os grupos mostraram tendências a desvios lineares nas direções mesial, gengival e labial. Não houve diferença estatisticamente significativa entre os dois grupos para a taxa de descolagem imediata (10,7% e 7,1% para o primeiro e o segundo grupos, respectivamente, p=0,295). Conclusões: As guias de colagem indireta impressas em 3D foram mais precisas em termos de desvios lineares do que as guias termoformadas a vácuo. Os dois tipos de guias apresentaram controle angular semelhante.

Effect of second molar eruption on efficiency of maxillary first molar distalization using Carriere distalizer appliance.

INTRODUCTION: Maxillary molar distalization is a common approach for correcting dental Class II malocclusions. OBJECTIVE: This study aimed at comparing the outcomes of maxillary first molar distalization using the Carriere appliance before and after second molar eruption. METHODS: Two groups of patients with dental Class II malocclusions were treated with Carriere distalizer appliance with heavy rectangular mandibular wire and lingual arch for anchorage. Patients of the first group presented unerupted maxillary second molars during the distalization period. In the second group, maxillary second molars were in occlusion on treatment onset. Cone beam computed tomography images were taken at the beginning of treatment and after finishing molar distalization, to compare both groups regarding first molar distalization, intrusion, mesiodistal tipping, buccolingual torquing and rotation, anchorage loss and skeletal changes. Also, the treatment durations were compared. RESULTS: The mean first molar distalization period in the first group (19.2 ± 1.6 weeks) was significantly smaller than the second group (23.3 ± 2.3 weeks). The amount of maxillary first molar distalization was significantly greater, while the amount of rotation was significantly smaller in the first group. No statistically significant differences in the amounts of maxillary first molar intrusion, mesiodistal tipping and buccolingual torquing between both groups was found. Mandibular incisor labiolingual torquing and mandibular first molar mesialization and mesiodistal tipping were significantly greater in the second group. CONCLUSIONS: Maxillary first molar distalization before maxillary second molar eruption is more efficient, with less anchorage loss than after second molar eruption.

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.