Dental implants have become a widely accepted solution for replacing missing teeth, offering superior function, aesthetics, and longevity compared to conventional prosthetic options (1). Despite their high success rates, implant-supported prostheses are susceptible to various complications, which can affect their long-term stability and patient satisfaction (2,3). These complications may be biological, such as peri-implantitis, or mechanical, including prosthetic failures like screw loosening, abutment fractures, veneer chipping, and prosthetic misfit (4,5). 

Among prosthetic complications, screw loosening is one of the most frequently reported issues, which can lead to instability and potential implant failure if not addressed promptly (6). Similarly, ceramic veneer chipping compromises the aesthetic and functional aspects of the restoration, often necessitating repairs or replacements (7). Abutment fractures, though less common, pose significant challenges as they may require complex interventions, including abutment replacement or implant retrieval (8). Prosthetic misfit, resulting from inaccuracies in impression techniques or laboratory fabrication, can contribute to occlusal discrepancies and implant overload, further increasing the risk of failure (9,10).

The incidence and nature of prosthetic complications can vary based on multiple factors, such as the type of prosthetic design, material selection, implant-abutment connection, and occlusal loading (11,12). Fixed partial dentures and implant-supported overdentures tend to exhibit a higher complication rate than single crowns due to their larger structural complexity and functional load distribution (13). Identifying and addressing these complications is crucial to improving treatment outcomes and enhancing the long-term success of implant prostheses.

This study aims to assess the frequency and types of prosthetic complications associated with dental implants, providing insights into their prevalence and possible contributing factors. Understanding these issues will help clinicians optimize implant prosthetic protocols, minimize failures, and improve patient satisfaction.

Study Design and Population

This retrospective study was conducted to evaluate the prosthetic complications associated with dental implants. A total of 120 patients who had received 200 dental implants between 2018 and 2023 were included in the study. The selection criteria included patients who had undergone implant placement and prosthetic rehabilitation with a follow-up period of at least 12 months. Patients with systemic conditions affecting bone healing or implant survival, as well as those with inadequate follow-up records, were excluded.

Data Collection

Patient records were reviewed to gather relevant information, including age, gender, implant site, type of prosthesis, and reported prosthetic complications. The types of implant-supported prostheses analyzed included single crowns, fixed partial dentures, and implant-supported overdentures. Prosthetic complications were categorized into screw loosening, abutment fractures, veneer chipping, and prosthetic misfit.

Assessment of Prosthetic Complications

Each patient underwent clinical and radiographic evaluation during follow-up visits to assess prosthesis integrity. Screw loosening was identified through patient complaints of mobility and confirmed by torque testing. Abutment fractures were diagnosed based on clinical examination and radiographic findings. Veneer chipping was documented when any fracture or detachment of the prosthetic veneering material was observed. Prosthetic misfit was evaluated using clinical fit assessment techniques, including tactile sensation, occlusal analysis, and radiographic verification.

Statistical Analysis

All collected data were tabulated and analyzed using descriptive statistics. The prevalence of different prosthetic complications was expressed as percentages. The chi-square test was applied to determine the statistical significance of the association between prosthetic complications and the type of prosthesis, with a significance level set at p < 0.05. Statistical analysis was performed using SPSS software (Version 26, IBM Corp., USA).

A total of 120 patients with 200 dental implants were analyzed in this study. The mean age of the patients was 45.6 ± 10.2 years, with 65 males (54.2%) and 55 females (45.8%). The distribution of implant-supported prostheses included 100 single crowns (50%), 60 fixed partial dentures (30%), and 40 implant-supported overdentures (20%).

Incidence of Prosthetic Complications

Prosthetic complications were observed in 70 out of 200 implants (35%). The most frequently encountered complication was screw loosening, affecting 28 implants (40%), followed by veneer chipping in 18 cases (25%), abutment fractures in 14 cases (20%), and prosthetic misfit in 10 cases (15%) (Table 1).

Prosthetic Complications Based on Type of Restoration

The occurrence of complications varied depending on the type of prosthesis. Fixed partial dentures exhibited the highest complication rate (45%), followed by implant-supported overdentures (37.5%) and single crowns (30%). Screw loosening was more common in implant-supported overdentures (50%), while veneer chipping was most frequently observed in fixed partial dentures (30%) (Table 2).

Statistical Analysis

A significant association was found between the type of prosthesis and the incidence of prosthetic complications (p < 0.05). Patients with fixed partial dentures were more likely to experience multiple complications compared to those with single crowns.

Tables

Table 1: Frequency of Prosthetic Complications in Dental Implants

(Table 1: Distribution of prosthetic complications among the studied implants.)

Table 2: Distribution of Prosthetic Complications Based on Prosthesis Type

(Table 2: Frequency of prosthetic complications among different types of implant-supported prostheses.)

These findings highlight the need for careful prosthesis selection and regular follow-up to minimize prosthetic complications in implant-supported restorations.

Prosthetic complications in implant-supported restorations remain a significant concern despite advancements in implant dentistry. This study aimed to assess the prevalence and types of prosthetic complications associated with different implant-supported prostheses. The findings indicate that 35% of the implants experienced at least one prosthetic complication, with screw loosening being the most frequently observed issue (40%), followed by veneer chipping (25%), abutment fractures (20%), and prosthetic misfit (15%). These results are consistent with previous studies that report mechanical failures as a common challenge in implant prosthodontics (1,2).

Screw loosening was the most prevalent complication, affecting nearly half of the implant-supported overdentures. This complication has been widely reported in literature, with studies indicating that it may result from inadequate torque application, occlusal overload, or implant-abutment misfit (3,4). Factors such as screw material, preload, and patient-specific occlusal forces also influence the likelihood of screw loosening (5). Proper tightening protocols, the use of torque-controlled devices, and periodic follow-ups can help mitigate this issue (6).

Veneer chipping, reported in 25% of cases, was most frequently observed in fixed partial dentures. The high incidence of chipping can be attributed to the brittleness of ceramic materials and occlusal stress distribution (7). Studies have shown that zirconia-based restorations are more resistant to chipping compared to porcelain-fused-to-metal prostheses, highlighting the role of material selection in minimizing veneer fractures (8,9). Additionally, occlusal adjustments and regular maintenance can help reduce the risk of veneer chipping (10).

Abutment fractures were encountered in 20% of cases, a finding in agreement with previous research indicating that excessive occlusal forces and biomechanical stress concentration contribute to abutment failures (11). Implant systems with weaker abutment connections or those subjected to repeated mechanical stress are more prone to fractures (12). The choice of abutment material, along with precision in fit and appropriate occlusal design, is essential for reducing the risk of fractures (13).

Prosthetic misfit, reported in 15% of cases, has been associated with inadequate impression techniques and laboratory errors. Misfit between the prosthesis and the implant platform can lead to biomechanical complications, including peri-implant bone loss and screw loosening (14). Studies emphasize the importance of digital impression techniques, CAD/CAM technology, and passive fit verification to ensure precise prosthetic adaptation (15).

The variation in complication rates among different prosthetic designs highlights the importance of prosthesis selection. In this study, fixed partial dentures had the highest complication rate (45%), followed by implant-supported overdentures (37.5%) and single crowns (30%). Similar findings have been reported in previous research, attributing the higher complication rate in fixed prostheses to their structural complexity and greater functional load distribution (2,9). Single crowns exhibited a lower complication rate, which aligns with studies suggesting that smaller prosthetic units experience reduced biomechanical stress and are less prone to technical failures (6,12).

Despite the valuable insights provided by this study, certain limitations should be acknowledged. The retrospective design limits the ability to establish causative factors, and the sample size may not be representative of all patient populations. Additionally, the follow-up period varied among patients, which could have influenced the reported incidence of complications. Future prospective studies with standardized follow-up protocols are needed to further evaluate long-term prosthetic success and failure rates.

In conclusion, prosthetic complications remain a common challenge in implant dentistry, with screw loosening and veneer chipping being the most frequently encountered issues. Proper prosthetic planning, material selection, and regular maintenance play crucial roles in minimizing these complications. Clinicians should emphasize the importance of long-term follow-up and evidence-based protocols to enhance the longevity and success of implant-supported prostheses.

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