Implant survival in the anterior mandible: A retrospective cohort study.

OBJECTIVE: This study aims to report the implant survival rate of dental implants of partially dentate patients in the anterior mandible and the potential risk indicators for implant failure. MATERIALS AND METHODS: Patients with implant-supported restorations of single or multiple teeth in the anterior mandible restored with fixed partial implant-supported restorations were evaluated. Patient demographic data, implant placement timing, and loading protocol, biological and/or technical complications at the time of the last clinical and radiographic follow-up visit were registered. Survival rate, success rate, and potential risk indicators for implant failure were calculated. RESULTS: A total of 108 patients and 186 implants with a mean follow-up period of 5.48 years (0.1-11.34 years) were included. The 11.3-year cumulative survival rate was 90.9%. Immediate implant placement (OR = 2.75) (p = .08) and immediate implant loading (OR = 8.8) (p = .02*) indicated a higher risk of failure than late implant placement or loading. When combining both categories (type 1A), an OR = 10.59 (p = .04*) for implant failure was found compared to category 4C. Implants placed following static-computer-assisted implant surgery (S-CAIS) showed less risk of failure compared to freehand implant placement (OR = 0.18; 95% CI: 0.02-1.37) (p = .09). CONCLUSIONS: The survival rate of implants placed in the anterior mandible was considerably low (90.9%). S-CAIS, late placement, and conventional loading are protective factor against implant failure in the anterior mandible.

Fourteen Year Follow-Up of Randomized Clinical Trials of Active Robotic-Assisted Total Hip Arthroplasty.

BACKGROUND: Active robotic total hip arthroplasty (THA) has been used clinically for over 20 years, but long-term results have never been studied. The aims of this study are to determine whether active robotic THA improves clinical outcomes and results in fewer revisions over a long-term follow-up. METHODS: Patients from 2 US Food and Drug Administration clinical trials (1994-1998 and 2001-2006) who had undergone THA using either an active robotic system or a traditional manual technique were examined to determine if any differences existed in radiographic analysis and patient pain and function using the University of California, Los Angeles; visual analog scale; Health Status Questionnaire (HSQ) pain; HSQ role physical; HSQ physical functioning; Harris pain scores; and the total Western Ontario and McMaster Universities Osteoarthritis Index scores at a mean follow-up of 14 years. RESULTS: The ROBODOC group had statistically significant higher HSQ pain and Harris pain scores and lower Western Ontario and McMaster Universities Osteoarthritis Index scores. There was no statistically significant difference in probability of a revision for wear between the groups (χ2 = 1.80; P = .179), and no revisions for loosening in either group. CONCLUSION: Prior studies have demonstrated improved implant fit and alignment with the use of this active robot system. This long-term study now shows no failures for stem loosening at a mean follow-up of 14 years and small but potentially important improvements in clinical outcomes in the robot group.

Computer-assisted surgery for replacement of the temporomandibular joint with customized prostheses: can we validate the results?

PURPOSE: Replacing the temporomandibular joint poses an important challenge to maxillofacial surgeons, and for certain disorders, it represents the treatment's gold standard. Computer-assisted surgery (comprising preoperative virtual planning, virtual intraoperative navigation and 3D printing) is a useful tool for this type of surgery. However, we do not know if and how much the final position of the prosthesis differs, in absolute values, from what was planned virtually in the preoperative phase. We propose a comparative result validation system for temporomandibular joint replacement METHODS: In the present study, we propose a comparative validation system using overlapping images, between the model obtained with preoperative virtual planning and the postoperative result. RESULTS: The mean difference for all screws of the glenoid prosthesis was 2.08 mm (range, 1.20-3.03) and for all screws of the condylar prosthesis it was 2.33 mm (range, 1.16-3.56). Mean overall difference between both prostheses in all patients was 2.21 mm (range, 1.16-3.56). CONCLUSIONS: The validation system proposed by overlapping pre- and postoperative images in temporomandibular joint replacement allowed us to establish differences in absolute values between the virtual preoperative model and the actual postoperative result expressed in millimeters.

Laboratory test of Single Landmark registration method for ultrasound-based navigation in laparoscopy using an open-source platform.

PURPOSE: Test the feasibility of the novel Single Landmark image-to-patient registration method for use in the operating room for future clinical trials. The algorithm is implemented in the open-source platform CustusX, a computer-aided intervention research platform dedicated to intraoperative navigation and ultrasound, with an interface for laparoscopic ultrasound probes. METHODS: The Single Landmark method is compared to fiducial landmark on an IOUSFAN (Kyoto Kagaku Co., Ltd., Japan) soft tissue abdominal phantom and T2 magnetic resonance scans of it. RESULTS: The experiments show that the accuracy of the Single Landmark registration is good close to the registered point, increasing with the distance from this point (12.4 mm error at 60 mm away from the registered point). In this point, the registration accuracy is mainly dominated by the accuracy of the user when clicking on the ultrasound image. In the presented set-up, the time required to perform the Single Landmark registration is 40% less than for the FLRM. CONCLUSION: The Single Landmark registration is suitable for being integrated in a laparoscopic workflow. The statistical analysis shows robustness against translational displacements of the patient and improvements in terms of time. The proposed method allows the clinician to accurately register lesions intraoperatively by clicking on these in the ultrasound image provided by the ultrasound transducer. The Single Landmark registration method can be further combined with other more accurate registration approaches improving the registration at relevant points defined by the clinicians.

A novel electromagnetic tracking system for surgery navigation.

OBJECTIVE: This paper proposes the development of a novel electromagnetic tracking system for navigation surgery. Main objective is to provide a system able to operate in a wide tracking volume to make easier and efficient the surgical procedures by assuring high measurement accuracy. METHODS: A new field generator consisting in five transmitting coils excited with Frequency Division Multiplexing technique has been developed. Attention is devoted to designing and arrangement of the coils to assure high sensitivity, system scalability and a homogeneous magnetic field inside working volume. A suitable technique based on Look-Up-Table is applied for sensor position calculation and an anthropomorphic robot is used for table calibration. RESULTS: Experimental tests highlight a good repeatability of the measurement data and a negligible noise influence for the proposed system. The obtained tracking volume is wider with respect to the commercial tracking device used in surgical applications and seem promising. CONCLUSION: The main characteristic of the developed system consists of: scalable and modular configuration of Field Generator, high measured sensitivity due to the increased number of transmitting coils with respect to the classical configuration and large tracking volume. The development of the proposed magnetic tracking systems with high accuracy and wide working volume allows to promote broader utilization of advantaged techniques in surgery procedures for both improving the effectiveness and decreasing the invasiveness of medical interventions.

Preliminary study on application of augmented reality visualization in robotic thyroid surgery.

PURPOSE: Increased robotic surgery is attended by increased reports of complications, largely due to limited operative view and lack of tactile sense. These kinds of obstacles, which seldom occur in open surgery, are challenging for beginner surgeons. To enhance robotic surgery safety, we created an augmented reality (AR) model of the organs around the thyroid glands, and tested the AR model applicability in robotic thyroidectomy. METHODS: We created AR images of the thyroid gland, common carotid arteries, trachea, and esophagus using preoperative CT images of a thyroid carcinoma patient. For a preliminary test, we overlaid the AR images on a 3-dimensional printed model at five different angles and evaluated its accuracy using Dice similarity coefficient. We then overlaid the AR images on the real-time operative images during robotic thyroidectomy. RESULTS: The Dice similarity coefficients ranged from 0.984 to 0.9908, and the mean of the five different angles was 0.987. During the entire process of robotic thyroidectomy, the AR images were successfully overlaid on the real-time operative images using manual registration. CONCLUSION: We successfully demonstrated the use of AR on the operative field during robotic thyroidectomy. Although there are currently limitations, the use of AR in robotic surgery will become more practical as the technology advances and may contribute to the enhancement of surgical safety.

Cirugía guiada para la colocación de implantes de longitud estándar en maxilar inferior posterior atrófico, sin regeneración ósea: informe de caso / Use of guided surgery for standard length implant placement in atrophic posterior mandible, without bone regeneration: case report

Objetivo: Presentar el uso de la cirugía guiada para la resolución quirúrgico-protética de un caso clínico con colocación de implantes de longitud estándar (>7 mm) en un maxilar inferior atrófico, sin regeneración ósea guiada. Caso clínico: Una paciente que requería terapia con implantes en sectores posteroinferiores se presentó en la Cátedra de Odontología Integral Adultos de la Facultad de Odontología de la Universidad de Buenos Aires. Primero se realizó una tomografía computarizada de haz cónico del maxilar inferior para evaluar la disponibilidad ósea. La planificación se efectuó siguiendo un protocolo digital a fin de optimizar la selección de los implantes y su instalación en función de la futura rehabilitación protética y el tejido óseo disponible. Después se escanearon ambos maxilares y el registro intermaxilar; estas imágenes ­junto con las correspondientes a la tomografía (DICOM)­ fueron importadas como archivos (STL) a un software específico de diseño para determinar digitalmente la posición 3D ideal de los implantes y diseñar una guía quirúrgica de precisión. Luego se realizó la cirugía de instalación de los implantes con la guía quirúrgica, y finalmente los implantes fueron rehabilitados por medio de coronas cemento-atornilladas. Conclusión: El uso de la cirugía guiada permitió optimizar el tejido óseo disponible para la instalación de implantes en función de la futura rehabilitación protética (AU)

Aim: To present the use of guided surgery for the prosthetic resolution of a clinical case with placement of implants of standard length (>7 mm) in an atrophic posterior mandible, with no need of bone regeneration. Clinical case: A patient who required implants in the posterior sectors of the mandible attended to the department of Odontología Integral Adultos, Facultad de Odontología, Universidad de Buenos Aires, Argentina. A dental cone beam computed tomography (CBCT scan) of the lower jaw was done to assess bone availability and was decided to perform guided surgery for accurate implant placement. Both maxillaries and intermaxillary occlusal registration were scanned and imported into files (STL) together with those of the CBCT scan (DICOM) into specific design software. Following the digital protocol using a surgical guide the implants were placed and then restored with cemented-screwed crowns. Conclusion: Guided surgery allowed planning implant placement, guided by the final position of the prosthetic restoration, and optimizing the available bone (AU)