Three-dimensional assessment of virtual bracket removal for orthodontic retainers: A prospective clinical study

This is a prospective clinical study aimed at introducing a method to visualise the location of an air leak and to identify the bulla responsible on three-dimensional (3-D) cine CT. In 10 patients with spontaneous pneumothorax, dynamic 320-detector row CT was performed with injection of 0.9% saline into the affected pleural cavity via a preplaced chest tube. In eight cases, 3-D cine CT thoracography revealed the location of the air leak and the bulla responsible (7 cases: air stream sign; 1 case: repeated collapse and expansion of a bulla with the patient's breathing).

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Does the macro design of an implant affect the accuracy of template-guided implantation? A prospective clinical study

International Journal of Implant Dentistry ◽

10.1186/s40729-021-00320-3 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Sigmar Schnutenhaus ◽

Cornelia Edelmann ◽

Heike Rudolph

Keyword(s):

Clinical Study ◽

Soft Tissues ◽

Three Dimensional ◽

Prospective Clinical Study ◽

Angular Deviation ◽

Optimal Position ◽

Mean Values ◽

Implant Placement ◽

High Level ◽

Achievable Accuracy

Abstract Background An implant prosthesis aims to ensure the best possible rehabilitation of function and esthetics following tooth loss. Template-guided insertion is used to achieve an optimal position of the implant with regard to prosthetic restorability, bone availability, and condition of the surrounding soft tissues. The accuracy of template-guided implant placement is subject to various influencing factors. The clinically achievable accuracy depending on the macro design of the implant body was investigated in this prospective clinical study. Material and methods In this prospective clinical study, 20 implants were placed in 20 patients. The implant had a pronounced conical outer geometry (Conelog ProgressiveLine, Camlog Wimsheim, Germany). Data from a study using an implant with a distinct cylindrical outer geometry were used as a comparison group (Conelog ScrewLine, Camlog, Wimsheim, Germany). The clinically achieved implant position was compared with the planned position. Results The evaluation of the two-dimensional deviations in direction resulted in the following mean values (standard deviation) at the shoulder: 0.42 mm (0.33) in the buccolingual direction, 0.27 mm (0.25) in the mesiodistal direction, and 0.68 mm (0.55) in the apicocoronal direction. The mean angular deviation was 4.1° (2.3). The three-dimensional (3D) deviation was 0.94 mm (0.53) at the shoulder and 1.36 mm (0.62) at the apex of the implant. Significant differences between implants with different macro designs were found in the apicocoronal direction. In connection to this, a significant 3D deviation was found at the implant shoulder. Conclusions Significant differences in height were found between the groups. The study had shown that the macro design of an implant has no influence on accuracy in all other directions. Overall, the implants showed a high level of accuracy and a low variation in values. The values were in the range determined by the template-guided insertion system in numerous other investigations. This provides good predictability of prosthetic rehabilitation. Trial registration German Register for Clinical Studies (DRKS-ID: DRKS000018939). Date of registration: November 11, 2019.

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