Clinical accuracy of flapless computer-guided surgery for implant placement in edentulous arches.

PURPOSE: Although flapless computer-guided implant placement provides important benefits, deviations from the planned implant placement in the edentulous arch may pose significant risks. This study evaluated the reliability and accuracy of a flapless computer-guided surgical approach. MATERIALS AND METHODS: Computer-generated preoperative implant planning was compared to actual placement by cone-beam computerized tomography (CBCT) scanning of patients before and after surgery. A well-fitting complete denture or optimized prosthetic tooth arrangement was used and converted to a radiographic template. Prior to scanning, esthetics and functional aspects were checked clinically. The implant positions were virtually determined by the implant planning software relative to the bone structure and prospective tooth position. After implant placement, new CBCT scans were obtained for each subject. Software was used to fuse the images of the planned and placed implants, and the locations and axes were compared. The normality of the data distribution was evaluated by the Kolmogorov-Smirnov test. Mean values were compared between groups based on the upper or lower jaws with the t test for independent samples. The level of significance was fixed at 5%. RESULTS: Sixty-two implants were placed in edentulous arches with stereolithographic surgical guides in 14 patients. Damage due to implant placement was not observed in any critical anatomical structure. Compared to the planned implants, placed implants showed mean and standard deviation linear measurements at the cervical, middle, and apical implant portions of 2.17 (± 0.87), 2.32 (± 1.52), and 2.86 (± 2.17) mm, for the maxilla, and 1.42 (± 0.76), 1.42 (± 0.76), and 1.42 (± 0.76) mm, for the mandible, respectively. The angular deviations were 1.93 (± 0.17) and 1.85 (± 0.75) degrees for the maxilla and mandible, respectively. The linear deviation differed significantlybetween the upper and lower jaws, but the angular deviation did not. CONCLUSION: Flapless computer-guided surgery may be a viable treatment option for rehabilitating the edentulous arch.

Estabelecimento de um protocolo clínico controlado para a cirurgia guiada sem retalho em maxilas totalmente edêntulas / Establishment of a controlled clinical protocol for flapless-guided surgery on completely edentulous maxillary arches

O objetivo deste trabalho foi verificar a precisão da técnica de cirurgia guiada e sem retalho, comparando os desvios angulares e lineares dos implantes cone-morse antes e depois da cirurgia, baseado em cortes tomográficos gerados em um ambiente tridimensional virtual computadorizado. Cinco pacientes com maxilas totalmente edêntulas foram utilizados neste estudo piloto. Após o planejamento reverso para montagem dos dentes e confecção do guia tomográfico, TCs foram obtidas com cortes de 0,2 mm de espessura, e as imagens geradas no software Dental Slice (Bioparts) para posicionamento dos implantes cone-morse Titamax EX (3,5-3,75 mm de diâmetro; Neoguide, Neodent). Após a cirurgia, novas TCs foram realizadas de acordo com o mesmo protocolo e inseridas no software. O desvio angular médio foi 2,033 ± 0,782º; a diferença linear na posição da plataforma, terço médio e apical foi 1,082 ± 0,907 mm, 1,599 ± 1,22 mm e 2,542 ± 2,047 mm, respectivamente. Todas as próteses com infraestrutura metálica e recobrimento de resina acrílica foram instaladas após 48 horas e os ajustes oclusais depois de 72 horas. Nenhuma complicação foi vista clinicamente, e as próteses e implantes permaneceram em função. Dentro dos limites deste estudo, os resultados demonstraram que a técnica é segura e precisa para ser utilizada nos consultórios. Entretanto, estes valores devem ser confirmados por estudos posteriores.

The aim of this study was to evaluate the precision of flapless, guided-surgery comparing angular and linear deviations of cone-morse dental implants before and after surgical procedures through CT slices generated on a computerized three-dimensional virtual environment. Five completely edentulous patients were enrolled in this pilot study. After reverse planning for tooth set-up and tomographic guide fabrication, CTs were made 0,2mm thick with images generated on Dental Slice (Bioparts) for placement of Titamax EX cone-morse implants (Neoguide, Neodent; 3.5-3.75mm in diameter). After implant placement, new CTs were made following the same protocol and transferred to Dental Slice software. Mean angular deviation values were of 2.033 ± 0.782º; registered linear differences at implant platform, middle and apical thirds were 1.082 ± 0.907mm, 1.599 ± 1.22mm, and 2.542 ± 2.047mm, respectively. All acrylic-veneered, metal-reinforced definitive prostheses were installed after 48 hours and occlusal adjustments provided after 72 hours. No clinical complications were seen, with all implants and prostheses remaining into function. Within the limits of this study, the results showed that this technique is safe and accurate for routine dental practice. However, these values must be confirmed in further studies.