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To analyze the effect of a computer-aided static navigation technique and mixed reality technology on the accuracy of orthodontic micro-screw placement. Material and methods: Two hundred and seven orthodontic micro-screws were placed using either a computer-aided static navigation technique (NAV), a mixed reality device (MR), or a conventional freehand technique (FHT). Accuracy across different dental sectors was also analyzed. CBCT and intraoral scans were taken both prior to and following orthodontic micro-screw placement. The deviation angle and horizontal deviation were then analyzed; these measurements were taken at the coronal entry point and apical endpoint between the planned and performed orthodontic micro-screws. In addition, any complications resulting from micro-screw placement, such as spot perforations, were also analyzed across all dental sectors. Results: The statistical analysis showed significant differences between study groups with regard to the coronal entry-point (p < 0.001). The NAV study group showed statistically significant differences from the FHT (p < 0.001) and MR study groups (p < 0.001) at the apical end-point (p < 0.001), and the FHT group found significant differences from the angular deviations of the NAV (p < 0.001) and MR study groups deviations (p = 0.0011). Different dental sectors also differed significantly. (p < 0.001) Additionally, twelve root perforations were observed in the FHT group, while there were no root perforations in the NAV group. Conclusions: Computer-aided static navigation technique enable more accurate orthodontic micro-screw placement and fewer intraoperative complications when compared with the mixed reality technology and conventional freehand techniques.

To analyze the influence of the computer-aided static navigation technique on the accuracy of placement of orthodontic micro-screws. One hundred and thirty-eight orthodontic micro-screws were randomly assigned to the following study groups: Group A. orthodontic micro-screw placement using a computer-aided static navigation technique (n = 69), B. orthodontic micro-screw placement using the conventional freehand technique (n = 69). In addition, the accuracy in the canine–premolar, premolar and molar sectors was analyzed in each study group. Cone-beam computed tomography and intraoral scans were taken both prior and subsequent to orthodontic micro-screw placement. The images were then uploaded using a 3D implant planning software, where the deviation and horizontal angles were analyzed using a multivariate linear model. These measurements were taken at the coronal entry point and apical endpoint between the planned orthodontic micro-screws. In addition, any complications resulting from micro-screw placement, such as spot perforations, were also analyzed in all dental sectors. The statistical analysis showed significant differences between the two study groups with regard to the coronal entry-point, apical end-point (p &lt, 0.001) and angular deviations (p &lt, 0.001) between the computer-aided static navigation technique and freehand technique study groups. Moreover, statistically significant differences were showed between the different dental sectors (p &lt, 0.001). Additionally, twelve root perforations were observed at the conventional free hand technique study group while there were no root perforations in the computer-aided static navigation technique study group. The results showed that the computer-aided static navigation technique enables a more accurate orthodontic micro-screw placement with less intraoperative complications when compared with the conventional freehand technique.

To analyze the influence of the operator experience on the accuracy of orthodontic self-tapping micro-screws placement, a total of 60 orthodontic self-tapping micro-screws were randomly distributed into two study groups: Group A. Orthodontic micro-screws placement by an orthodontist with 10 years of experience (n = 30), and B. Orthodontic micro-screws placement by an orthodontist student without experience (n = 30). Cone-beam computed tomography scans and intraoral scans were performed before and after the orthodontic self-tapping micro-screws placement and uploaded in 3D implant-planning software to analyze the deviation angle and the horizontal deviation measured at the coronal entry point and apical endpoint between orthodontic micro-screws planned and performed. In addition, intraoperative complications such as root perforations after orthodontic self-tapping micro-screws placement and fracture of the orthodontic self-tapping micro-screws during their placement were also analyzed. The paired t-test revealed statistically significant differences at the apical endpoint (p = 0.004) of planned and performed orthodontic self-tapping micro-screws between the orthodontist with 10 years of experience and the orthodontist student without experience. However, the paired t-test revealed no statistically significant differences at the coronal entry point (p = 0.220) and angular deviations (p = 0.602) of planned and performed orthodontic self-tapping micro-screws between the orthodontist with 10 years of experience and the orthodontic student without experience. Furthermore, five root perforations were observed in the no experience study group and three orthodontic self-tapping micro-screws were fractured in each study group. In conclusion, the results show that the greater experience of the operator influences the accuracy of orthodontic micro-screws placement, resulting in less intraoperative complications.

Background: To determine the optimal implantation site of orthodontic micro-screws based on cone beam computed tomography (CBCT) analysis in the mandibular anterior tooth region, provide a theoretical basis for orthodontic implant placement and improve post-implantation stability.Methods: Forty patients who underwent CBCT scanning were selected for this study. CBCT scanning was applied to measure the interradicular distance, buccolingual dimension, labial cortical bone thickness and lingual cortical bone thickness between mandibular anterior teeth at planes 2, 4, 6, and 8 mm below the alveolar ridge crest. The data were measured and collected to obtain a comprehensive evaluation of the specific site conditions of the alveolar bone.Results: The interradicular distance, buccolingual dimension and labial cortical bone thickness between the mandibular anterior teeth were positively correlated with the distance below the alveolar ridge crest (below 8 mm). The interradicular distance, buccolingual dimension, labial cortical bone thickness, and lingual cortical bone thickness were all greater than those in other areas between the lateral incisor root and canine incisor root 4, 6, and 8 mm below the alveolar ridge crest.Conclusion: The area between the lateral incisor root and the canine incisor root in planes 4, 6, and 8 mm from the alveolar ridge crest can be used as safe sites for implantation, while 8 mm below the alveolar ridge crest can be the optimal implantation site. An optimal implantation site can be 8 mm below the alveolar ridge crest between the lateral incisor root and the canine incisor root.

A utilização de dispositivos transitórios de ancoragem, como coadjuvante no tratamento ortodôntico, tem demonstrado, nos últimos anos, alta versatilidade de aplicação clínica, principalmente no que tange o uso dos miniimplantes. Estes aparatos surgem como alternativa para os casos em que a ancoragem se torna fator crítico para o sucesso do tratamento ortodôntico. Neste artigo, buscamos uma abordagem ampla do tema, incluindo: locais de instalação, procedimentos cirúrgicos, indicações, cuidados com a higiene e complicações mais freqüentes na utilização dos miniimplantes.Temporary anchorage devices, such as mini-implants, have been widely used over the last few years. These devices are very important where anchorage is a major factor for the successful outcome of orthodontic treatment. The authors will comment on the broader aspects of orthodontic treatment with application of mini-implants, choice of implant sites, discussing their indications, surgical procedures, post-surgical oral hygiene care and the most frequent complications.

A utilização de dispositivos transitórios de ancoragem, como coadjuvante no tratamento ortodôntico, tem demonstrado, nos últimos anos, alta versatilidade de aplicação clínica, principalmente no que tange o uso dos miniimplantes. Estes aparatos surgem como alternativa para os casos em que a ancoragem se torna fator crítico para o sucesso do tratamento ortodôntico. Neste artigo, buscamos uma abordagem ampla do tema, incluindo: locais de instalação, procedimentos cirúrgicos, indicações, cuidados com a higiene e complicações mais freqüentes na utilização dos miniimplantes. Temporary anchorage devices, such as mini-implants, have been widely used over the last few years. These devices are very important where anchorage is a major factor for the successful outcome of orthodontic treatment. The authors will comment on the broader aspects of orthodontic treatment with application of mini-implants, choice of implant sites, discussing their indications, surgical procedures, post-surgical oral hygiene care and the most frequent complications.

Mini-implant loss is often associated with physical and mechanical aspects that result from choosing an inappropriate placement site. It is worth highlighting that: a) Interdental alveolar bone crests are flexible and deformable. For this reason, they may not offer the ideal absolute anchorage. The more cervical the structures, the more delicate they are, thus offering less physical support for mini-implant placement; b) Alveolar bone crests of triangular shape are more deformable, whereas those of rectangular shape are more flexible; c) The bases of the alveolar processes of the maxilla and the mandible are not flexible, for this reason, they are more likely to receive mini-implants; d) The more cervical a mini-implant is placed, the higher the risk of loss; the more apical a mini-implant is placed, the better its prognosis will be; e) 3D evaluations play a major role in planning the use of mini-implants. Based on the aforementioned considerations, the hypotheses about mini-implant loss are as follows: 1) Deflection of maxillary and mandibular alveolar processes when mini-implants are more cervically placed; 2) Mini-implants placed too near the periodontal ligament, with normal intra-alveolar tooth movement; 3) Low bone density, low thickness and low alveolar bone volume; 4) Low alveolar cortical bone thickness; 5) Excessive pressure inducing trabecular bone microfracture; 6) Sites of higher anatomical weakness in the mandible and the maxilla; 7) Thicker gingival tissue not considered when choosing the mini-implant. As perdas de mini-implantes estão quase sempre relacionadas aos aspectos físicos e mecânicos decorrentes de uma escolha inadequada do local de inserção. Deve se destacar que: a) As cristas ósseas alveolares interdentárias têm flexão e se deformam, e podem não oferecer ancoragem tão absoluta. Quanto mais cervicais, as estruturas são mais delicadas e oferecem menos suporte físico para os mini-implantes; b) as cristas ósseas alveolares triangulares se deformam mais, e as retangulares são menos flexíveis; c) as bases do processo alveolar nos corpos da maxila e mandíbula não têm capacidade flexiva, e seu volume e estruturas são maiores, logo, são mais receptivas para mini-implantes; d) quanto mais próximo da cervical se coloca um mini-implante, maior é o risco de se perdê-lo; quanto mais apical se coloca o mini-implante, melhor é o seu prognóstico; e) avaliar a região tridimensionalmente representa um passo fundamental no planejamento do uso de mini-implantes. Com base nessas considerações, as hipóteses para a perda de mini-implantes são: 1) Deflexão do processo alveolar da maxila e mandíbula, quando fixados em posições mais cervicais; 2) proximidade com o ligamento periodontal e o movimento dentário intra-alveolar normal; 3) densidade óssea menor, pouca espessura e menor volume ósseo alveolar; 4) espessura menor da cortical óssea alveolar; 5) pressão excessiva, induzindo microfraturas ósseas trabeculares; 6) locais de maior fragilidade anatômica mandibular e maxilar; 7) espessura maior do tecido gengival não considerada na escolha do mini-implante.

P. 126-156, jul./ago. Submitted by JURANDI DE SOUZA SILVA (jssufba@hotmail.com) on 2011-09-30T13:38:33Z No. of bitstreams: 1 30890.pdf: 2723865 bytes, checksum: 728a5407c459c0b2c6d7f81eb1abfa80 (MD5) Made available in DSpace on 2011-09-30T13:38:33Z (GMT). No. of bitstreams: 1 30890.pdf: 2723865 bytes, checksum: 728a5407c459c0b2c6d7f81eb1abfa80 (MD5) Previous issue date: 2006 A utilização de dispositivos transitórios de ancoragem, como coadjuvante no tratamento ortodôntico, tem demonstrado, nos últimos anos, alta versatilidade de aplicação clínica, principalmente no que tange o uso dos miniimplantes. Estes aparatos surgem como alternativa para os casos em que a ancoragem se torna fator crítico para o sucesso do tratamento ortodôntico. Neste artigo, buscamos uma abordagem ampla do tema, incluindo: locais de instalação, procedimentos cirúrgicos, indicações, cuidados com a higiene e complicações mais freqüentes na utilização dos miniimplantes. Maringá