Comparison Between Cortical Drill and Cortical Tap and Their Influence on Primary Stability of Macro-Thread Tapered Implant in Thin Crestal Cortical Bone and Low-Density Bone

In vitro and in vivo accuracy of autonomous robotic vs. fully guided static computer-assisted implant surgery

OBJECTIVES

To assess the accuracy of autonomous robotic and fully guided static computer-assisted implant surgery (sCAIS) performed on models and patients.

MATERIALS AND METHODS

This study was divided into in vitro and in vivo sections. In vitro, 80 operators were assigned to two groups randomly. Forty operators performed forty autonomous robotic implant (ARI group) surgeries and the remaining forty operators carried out forty fully guided sCAIS (FGI group) surgeries on maxillary models, respectively. Each operator placed an implant in one maxillary model. In vivo, 60 patients with 113 implants from 2019 to 2023 (ARI group: 32 patients, 58 implants; FGI group: 28 patients, 55 implants) receiving implant surgeries were incorporated in this retrospective research. The preoperative and postoperative cone beam computer tomographs (CBCTs) were utilized to estimate the linear deviations and angular deviations in two-dimensional (2D) and three-dimensional (3D) space. The Pearson's chi-square test, Shapiro-Wilk test, Student's t test, Mann-Whitney U test and mixed models were applied, and p <0.05 was considered statistically significant.

RESULTS

In vitro, a total of 80 implants were enrolled and significant differences were found between the two groups (p < 0.001): The 3D deviation at the platform of ARI and FGI group was 0.58 ± 0.60 mm and 1.50 ± 1.46 mm, respectively, at the apex was 0.58 ± 0.60 mm and 1.78 ± 1.35 mm, respectively, and angle was 1.01 ± 0.87° and 2.93 ± 1.59°, respectively. Also, except for mesiodistal deviation at the implant platform, the rest linear and angular deviations in the ARI group were significantly lower than those in the FGI group in 2D space (p < 0.001). In vivo, a significantly lower mean of angular deviation (0.95 ± 0.50°, p < 0.001) and the linear deviation at both platform (0.45 ± 0.28 mm, p < 0.001) and apex (0.47 ± 0.28 mm, p < 0.001) were observed in ARI group when compared to the FGI group (4.31 ± 2.60°; 1.45 ± 1.27 mm; 1.77 ± 1.14 mm).

CONCLUSIONS

The use of autonomous robotic technology showed significantly higher accuracy than the fully guided sCAIS.

Comparison of Implant Surgery Methods of Cortical Tapping and Cortical Widening in Bone of Various Density: A Three-Dimensional Finite Element Study

PURPOSE

The primary stability of a dental implant is critical for successful osseointegration during immediate loading. The cortical bone should be prepared to achieve enough primary stability, but not overcompressed. In this study, we investigated the stress and strain distribution in the bone around the implant induced by the occlusal force applied during immediate loading at various bone densities by the FEA method to compare cortical tapping and widening surgical techniques.

MATERIALS AND METHODS

A three-dimensional geometrical model of a dental implant and bone system was created. Five types of bone density combination (D111, D144, D414, D441 and D444) were designed. Two surgical methods-cortical tapping and cortical widening-were simulated in the model of the implant and bone. An axial load of 100 N and an oblique load of 30 N were applied to the crown. The maximal principal stress and strain were measured for comparative analysis of the two surgical methods.

RESULTS

Cortical tapping showed lower maximal stress of bone and maximal strain of bone than cortical widening when dense bone was located around the platform, regardless of the direction of the applied load.

CONCLUSIONS

Within the limitations of this FEA study, it can be concluded that cortical tapping is biomechanically more advantageous to the implants under occlusal force during immediate loading, especially when the bone density around the platform is high.

On the Future Design of Bio-Inspired Polyetheretherketone Dental Implants

Polyetheretherketone (PEEK) is a promising implant material because of its excellent mechanical characteristics. Although this polymer is a standard material in spinal applications, PEEK is not in use in the manufacturing of dental implants, where titanium is still the most-used material. This may be caused by its relative bio-inertness. By the use of various surface modification techniques, efforts have been made to enhance its osseointegrative characteristics to enable the polymer to be used in dentistry. In this feature paper, the state-of-the-art for dental implants is given and different surface modification techniques of PEEK are discussed. The focus will lie on a covalently attached surface layer mimicking natural bone. The usage of such covalently anchored biomimetic composite materials combines many advantageous properties: A biocompatible organic matrix and a mineral component provide the cells with a surrounding close to natural bone. Bone-related cells may not recognize the implant as a foreign body and therefore, may heal and integrate faster and more firmly. Because neither metal-based nor ceramics are ideal material candidates for a dental implant, the combination of PEEK and a covalently anchored mineralized biopolymer layer may be the start of the desired evolution in dental surgery.