How Can Abutment or Central Screw Fracture After Implant Restoration Be Prevented?

Embark on a journey to discover proactive measures in our exploration titled "How Can Abutment or Central Screw Fracture After Implant Restoration Be Prevented?" Uncover valuable insights and strategies aimed at ensuring the durability and success of implant-supported restorations. Join us as we delve into preventive approaches that promise enhanced stability and longevity in the realm of dental implant procedures.

 

1. Prevention of Abutment or Central Screw Fracture

1.1 Preoperative Preparation

Comprehensive imaging data preparation is essential before surgery, with more complex cases benefiting from the creation of digital implant guides. Measurement of alveolar bone width and height is crucial to determine the ideal implant site. Addressing any significant bone deficiencies in the vertical or horizontal dimensions before implant surgery is paramount for long-term success. If there is noticeable elongation or inclination of adjacent teeth, it is advisable to perform orthodontic adjustments before proceeding with implant surgery. In cases where orthodontic treatment is indicated, initiating orthodontic therapy before implant surgery and ensuring adequate space for future restorations is recommended. Adequate preoperative clinical preparation and sufficient implantation experience are critical factors influencing the success of dental implants and the occurrence of related complications.

1.2 Minimizing Occlusal Load

Implants are more prone to excessive occlusal forces compared to natural teeth. Clinical strategies to reduce occlusal load often involve minimizing the occlusal contact area, cusp inclination, non-axial forces, cantilever length, and promoting light occlusion. Before final restoration, effective communication between clinicians and technicians is crucial for detailed descriptions of temporary restorations, including all necessary details to be reproduced in the final restoration. Clinical studies have shown that the 5-year success rates for restorations with and without cantilevers were 91.4% and 95.2%, respectively, with mechanical complication rates of 20.3% and 9.3%. Generally, cantilevers shorter than 15mm have a smaller impact. Specific recommendations to minimize occlusal load include reducing cantilevers, increasing the number of implants, adding evenly distributed contact points, evaluating occlusal habits, reducing crown diameter, decreasing cusp inclination, and adopting gradual loading for patients with poor bone quality. Choosing the optimal implant treatment approach is crucial for preventing excessive occlusal load and ensuring the long-term stability of implant-supported restorations.

1.3 Correcting Maladaptive Functional Habits

Research indicates that the incidence of mechanical complications in patients with bruxism and non-bruxism is 23% and 17.3%, respectively, with implant failure rates of 60% and 39%, respectively. For patients with bruxism or a habit of biting hard objects, the use of occlusal guards can significantly reduce the probability of abutment or screw fractures when combined with oral hygiene education.

1.4 Ensuring Sufficient Precision

Despite various manufacturers promoting highly adaptable custom abutments, non-standardized manufacturing processes may lead to mismatches between abutment screws and implants, causing microleakage or deformation during screw tightening. This is a critical factor predisposing to screw or abutment loosening and fractures. Therefore, it is advisable to use original manufacturer abutments and screws. When making impressions, selecting appropriate transfer coping and analog, and employing open-tray impression techniques can enhance accuracy, albeit with increased complexity and the need for a certain amount of space. Implant placement should ideally position the implant in the center of the occlusal surface to avoid forming an intra-crown cantilever. To ensure accuracy during torque application, using a torque wrench with calibrated markings is recommended.

2. Management of Abutment or Central Screw Fracture

In cases of abutment or screw loosening, replacing with a new screw from the original manufacturer is recommended when internal screw structure damage is uncertain, preventing recurrence of loosening or fracture. For screw-retained restorations, accessing the loose screw directly through the original screw hole and replacing it is viable. If the abutment is undamaged, simply replacing with a new screw is sufficient. For cement-retained restorations, caution is advised against blindly opening the screw channel. Instead, precise positioning, guided by imaging data, before addressing screw retention is recommended.

In the event of abutment or screw fracture, using the implant system's matching tool kit to remove the broken portion and then creating a new superstructure is the recommended approach. When cutting the abutment or screw, care should be taken to protect the internal threads of the implant. Microscope-assisted procedures are preferable if conditions allow to avoid compromising the later screw fixation for crown restoration. If removing the broken portion is not feasible, considering grinding away the broken part along with the internal threads and opting for a post-core crown restoration is an alternative. In cases where bone conditions allow, removing the original implant and implanting a new or larger diameter implant is a viable option.