Evaluation of Complications and Marginal Bone Loss Observed in Prosthetic Restorations Applied to Different Implant Abutment Connection Types: A Retrospective Study
1
Department of Prosthodontics, Faculty of Dentistry, Suleyman Demirel University, Isparta 32260, Turkey
2
Department of Prosthodontics, Faculty of Dentistry, Antalya Bilim University, Antalya 07190, Turkey
*
Author to whom correspondence should be addressed.
Prosthesis 2025, 7(3), 46; https://doi.org/10.3390/prosthesis7030046
Submission received: 4 March 2025
/
Revised: 17 April 2025
/
Accepted: 23 April 2025
/
Published: 7 May 2025
(This article belongs to the Collection Oral Implantology: Current Aspects and Future Perspectives)
Abstract
Purpose: The aim of this study was to evaluate the long-term clinical results of two different implant–abutment connection types (screw-retained/Morse locking taper), marginal bone loss, and complications in prosthetic restorations. Materials and Methods: In 2017–2018, 579 implants and 242 implant-supported restorations applied to 137 patients were included in the study. Patients were recalled every six months, clinical evaluations were accomplished, and complications were recorded. When examining the distribution of prosthetic restorations by type, it was determined that 38 (15.70%) were single crowns, 136 (56.19%) were fixed partial cement-retained bridge restorations, 53 (21.90%) were fixed partial screw-retained bridge restorations, and 15 (6.19%) were overdenture prostheses. Findings: Overall, complications included eighteen (21.68%) retention losses, nineteen (22.89%) instances of screw loosening, twenty-one (25.30%) veneer ceramic fractures, three (3.61%) acrylic base fractures, fourteen (16.87%) cases of peri-implantitis, and eight (9.64%) implant losses. Conclusions: Differences in complication rates were observed between implants with different implant–abutment connection designs. While no significant differences were found regarding annual mesial and distal marginal bone loss for implants with conical locking connections, a significant difference was detected in those with screw-retained connections. In both implant groups, mesial and distal marginal bone loss progressed gradually over the follow-up period.
1. Introduction
In recent years, dental implant applications have been evaluated using various parameters such as biomechanical, aesthetic, periodontal, and restorative material options. In these evaluations, the long-term success and prognosis of implant-supported prostheses have become increasingly important [1].
Periodontitis is a long-standing inflammatory condition triggered by bacterial activity, leading to a series of immune responses that gradually damage the supporting structures of the teeth. Advanced stages of this disease are the leading cause of tooth loss among adults, often resulting in impaired chewing efficiency, nutritional deficiencies, and a reduced quality of life [2].
In recent decades, there has been growing interest in regenerative procedures, driven by the increasing need for techniques that restore and regenerate lost tissues and organs [3].
Implant-supported fixed prosthetic restorations are generally indicated for single-tooth deficiencies and partially edentulous areas bounded by healthy adjacent teeth [4]. However, in completely edentulous cases, choosing between fixed and removable implant-supported prosthetic restorations is more complex. One deciding factor is the need for facial aesthetics and soft tissue support. If both fixed and removable options are feasible, the number and complexity of the required surgical procedures may also influence the decision. In cases of significant buccal and apicocoronal bone loss, extensive bone and soft tissue augmentation may be necessary for fixed prosthetic rehabilitation. Thus, when substantial facial soft tissue support and augmentation are needed, implant-retained removable prosthetic restorations offer a less invasive treatment alternative [5].
Implant systems consist of two primary components, the implant and the abutment, which connects the implant to the prosthesis. The choice of abutment and the design of the implant–abutment connection are among the most critical factors affecting the prognosis of prosthetic treatment [6].
Abutments for implant-supported prosthetic restorations are continually updated to meet diverse clinical requirements, enhance prosthetic success, and increase the longevity of the restoration. Many implant systems offer a variety of abutment shapes, materials, and connection designs to suit different prosthetic needs.
To achieve mechanically stable, functional, and aesthetically satisfactory restorations, selecting an appropriate abutment that fits the clinical situation is essential. The choice of abutment material, shape, type, and implant–abutment connection design plays a crucial role in the success of prosthetic treatment and patient satisfaction. In implant-supported restorations, both screw systems and conical locking connection systems are used. In screw systems, the connection between the implant and the abutment is secured by tightening a screw to a predetermined torque. Long-term studies of these systems have reported issues such as screw loosening, screw or abutment fractures, and other mechanical complications, as well as bacterial leakage at the implant–abutment interface or crown margin. The development of conical connection systems was aimed at addressing these mechanical and biological challenges [7].
In this study, two null hypotheses were established. The first hypothesis states that ‘there is no difference in marginal bone loss between screw-retained implants and conical locking connection implants’. The second hypothesis states that ‘there is no difference between screw-retained implants and conical locking connection implants in terms of prosthetic complications’.
The aim of this study is to evaluate the long-term clinical complications and marginal bone losses of implant-supported prosthetic restorations applied on implant systems with conical locking connections and implant systems with traditional screw-type connections.
2. Materials and Methods
This study, which was approved by the Süleyman Demirel University Clinical Research Ethics Committee (Approval No. 191, dated 7 July 2022), included patients who provided informed consent and received at least one implant according to the sterilization protocols at the Süleyman Demirel University Faculty of Dentistry, Department of Prosthetic Dentistry between 1 January 2017 and 31 December 2018.
Patients were selected from individuals without systemic diseases affecting their general health, bruxism or other parafunctional habits, malocclusion, or abnormal jaw relationships, inclusion and exclusion criteria for patients selected for this study showed in Table 1. A total of 137 patients (58 males and 79 females), aged between 23 and 82 years, were included. The prosthetic restorations of patients receiving two different implant–abutment connection types (conical and screw) from the same companies—NTA Implant (Switzerland), NTA Shorter Implant (Switzerland), and NTA Hybrid Implant (Switzerland) (Toros Dental, Antalya, Turkey)—were retrospectively evaluated. The types of prosthetic restorations were classified as single crowns, fixed partial bridges, and removable overdentures, and the restoration materials were recorded as metal–ceramic, zirconium-supported ceramic, and metal–acrylic resin restorations.
A statistical power analysis (G power analysis) was performed based on the clinical and radiographic evaluation results of this retrospective study to ensure meaningful data and statistically significant results. Using a survival rate (prevalence) of 97.56% obtained from previous studies, the minimum sample size was calculated as 37 patients, with a 5% deviation and a 95% confidence interval [8].
Kim et al. concluded that digital panoramic radiography is a simple and effective method for pre-implant evaluation and that vertical evaluation can provide accurate information [9]. Schropp et al. stated that magnification adjustments in digital panoramic radiography are possible with a reference ball calibration method for 1:1 image visualization on the screen and the use of software-based measurement tools [10]. In this study, measurements were similarly performed using 1:1 image calibration. Apaydın et al. stated that digital panoramic radiography can be used in implant surgery planning, with a 1 mm confidence interval for vertical measurements [11].
Patients who had completed dental implant and prosthetic treatment were called to the clinic for check-ups, and prosthetic restorations and complications that occurred during function were evaluated. In the examination of implants and implant-supported prostheses, complications such as retention losses of prosthetic restorations and retainers, abutment and abutment screw fractures, implant body fractures, prosthetic superstructure and substructure fractures, and acrylic base fractures were evaluated and recorded from the last control session to the last control session. In the control sessions, panoramic radiographs were taken from the patients at 66 Kv, 8 Ma, and 16 sec shooting values with the Planmeca ProMax device (Planmeca, Helsinki, Finland) at 12-month intervals in order to determine mesial, distal, and average bone losses around the implant. Measurements were made from the mesial and distal margins of the implants on panoramic radiographs using the CS6 (Adobe Photoshop CS6 Extended, USA, Photo Editing Application) program. Measurements were made by comparing panoramic radiographs taken immediately after the prosthetic loading of the implants with panoramic radiographs taken during the control.
Statistical Analysis
Data were analyzed using IBM SPSS Statistics v29.0 software (IBM, Chicago, IL, USA). The normality of the data distribution was assessed with the Kolmogorov–Smirnov test, and descriptive statistics were presented as means ± standard deviation. Repeated-measures analysis of variance (ANOVA) was employed to evaluate mean differences among groups, and multiple comparisons were conducted using the LSD test, with a significance level set at p < 0.01. Paired t-tests were used for comparisons within independent groups, and the chi-square test was applied to assess relationships between categorical variables. For these analyses, statistical significance was defined as p < 0.05.
3. Findings
The demographic distribution of the 137 patients (79 females (57.66%) and 58 males (42.33%)), who received a total of 579 implants, is summarized in Table 2. Among patients with screw-retained implants, 47 (54.65%) were female and 39 (45.34%) were male. In the group with conical locking connection implants, 21 (67.74%) were female and 10 (32.26%) were male. Additionally, in the group that received both screw-retained and conical locking connection implants, eleven (55%) were female and nine (45%) were male.
The distribution of implant-supported prosthetic restorations by type is presented in Table 3. Overall, prosthetic restorations were classified as follows: 38 (15.70%) single crowns, 136 (56.19%) fixed partial cement-retained bridges, 53 (21.90%) fixed partial screw-retained bridges, and 15 (6.19%) overdentures. For prostheses with conical locking connections, the distribution was seven (13.21%) single crowns, forty-two (79.25%) fixed partial cement-retained bridges, two (3.77%) fixed partial screw-retained bridges, and two (3.77%) overdentures. In contrast, for prostheses with screw connections, 31 (17.61%) were single crowns, 89 (50.57%) were fixed partial cement-retained bridges, 43 (24.43%) were fixed partial screw-retained bridges, and 13 (7.39%) were overdentures. In cases where both conical locking and screw-retained implant types were used, five (38.46%) were fixed partial cement-retained bridges and eight (61.54%) were fixed partial screw-retained bridges.
The distribution of implant-supported prosthetic restorations according to their materials is presented in Table 4. Overall, 213 (88.01%) restorations were metal–ceramic, 11 (4.55%) were zirconium substructured ceramic, and 18 (7.44%) were metal–acrylic resin. In the subgroup with conical locking connections, forty-six (88.46%) restorations were metal–ceramic, three (5.77%) were zirconium substructured ceramic, and three (5.77%) were metal–acrylic resin. For restorations with screw connections, 155 (88.07%) were metal–ceramic, six (3.41%) were zirconium substructured ceramic, and 15 (8.52%) were metal–acrylic resin. In cases where both conical locking and screw connections were used, 12 (85.71%) restorations were metal–ceramic and two (14.29%) were zirconium-based ceramic.
The distribution of complications associated with implant-supported prosthetic restorations is summarized in Table 5. Overall, complications included 18 (21.68%) retention losses, 19 (22.89%) instances of screw loosening, 21 (25.30%) veneer ceramic fractures, three (3.61%) acrylic base fractures, 14 (16.87%) cases of peri-implantitis, and eight (9.64%) implant losses. For restorations with conical locking connections, the complications were: nine (10.84%) retention losses, four (4.82%) screw loosenings, six (7.23%) veneer ceramic fractures, two (2.41%) acrylic base fractures, four (4.82%) cases of peri-implantitis, and six (7.23%) implant losses. In the screw-retained restorations, eight (9.64%) retention losses, fifteen (18.07%) screw loosenings, eight (9.64%) veneer ceramic fractures, one (1.20%) acrylic base fracture, four (4.82%) cases of peri-implantitis, and two (2.41%) implant losses were observed. In the group that included both connection types, one (1.20%) retention loss, seven (8.43%) veneer ceramic fractures, and six (7.23%) cases of peri-implantitis were recorded.
Table 6 presents a comparison of mesial and distal marginal bone loss in implants with conical locking and screw connections. Within both the conical locking and screw-retained implant groups, significant differences in marginal bone loss values were observed over time at 12, 24, 36, 48, and 60 months. Additionally, when comparing the marginal bone loss values between the conical locking connection implants and the screw-retained implants over time, a significant difference was detected (p < 0.001). This table compares the progression of marginal bone loss within each group over time.
Furthermore, when the mesial marginal bone loss values of all implants were compared with the distal values over time, no significant difference was detected (p > 0.05). Similarly, no significant difference was found between the mesial and distal marginal bone loss values when comparing the conical locking and screw-connected implant groups over time. This table provides comparative values of the main groups against each other (Table 7).
When the values of the mesial marginal bone loss variables and the distal marginal bone loss variables of all implants followed over time were compared, no significant difference was detected (p > 0.05).
When the values of the mesial marginal bone loss and distal marginal bone loss variables were compared between the conical locking implant and screw-connected implant groups over time, no significant difference was detected (p > 0.05). Please see the Table 8 below.
A chi-square analysis was performed to determine whether there were statistically significant differences between the groups.
For the first year following prosthetic restoration, 93.5% of implants with conical locking connections exhibited less than 1.5 mm of marginal bone loss on the mesial side, compared to 95.3% of implants with screw connections. On the distal side, 94.8% of implants with conical locking connections had less than 1.5 mm of marginal bone loss, whereas 90.1% of implants with screw connections met the same criterion.
At the fifth-year follow-up, the distributions changed. In total, 57.4% of implants with conical locking connections and 64.1% of implants with screw connections demonstrated less than 0.2 mm of marginal bone loss on the mesial side. For the distal side, 53.4% of implants with conical locking connections and 48.1% of implants with screw connections had less than 0.2 mm of marginal bone loss.
A statistically significant difference was found in the mesial and distal marginal bone loss values in implants with screw connections over each year (p < 0.05). Overall, the marginal bone loss in both the conical locking and screw-connected implant groups increased progressively over time during each annual follow-up period.
4. Discussion
Facial expression and smiling are crucial elements of human communication. Tooth loss not only leads to a loss of function and tissue but also poses significant social and psychological challenges. Implant-supported prostheses enhance chewing efficiency, contribute to bone tissue preservation, and improve overall oral function. Numerous long-term studies have confirmed the effectiveness of dental implant applications [12].
In our study, within the category of irreparable complications, a higher number of implant losses were observed in implants with conical locking connections. Marginal bone loss increased progressively over time in both the conical locking and screw-retained implant groups during each annual follow-up period.
Recent evaluations of dental implant applications have incorporated various parameters, including biomechanical, aesthetic, periodontal, and restorative material factors, with the long-term success and prognosis of implant-supported prostheses becoming critical criteria [1].
The development of biofilms is a key factor in microbial virulence. In the oral cavity, polymicrobial biofilms form on dental and mucosal surfaces, as well as on implants and dental materials, potentially leading to various diseases and complications. An imbalance in the oral biofilm may promote the proliferation of acidogenic species associated with dental caries, such as Streptococci, Lactobacilli, and Candida [13].
Currently, screw-type connections are the most widely used systems to achieve a secure implant–abutment interface. These systems rely on a screw preload generated by applying a predetermined torque during prosthesis placement. However, if occlusal loads exceed this preload, complications such as screw loosening or friction-induced deformation at the implant–screw interface may occur [14].
Conversely, the conical locking connection provides a secure interface through high contact pressure and friction resistance, significantly enhancing the system’s resistance to bending forces and overall stability. This mechanism results in reduced incidences of screw loosening. Numerous systematic reviews have evaluated the survival and complication rates of fixed and removable implant-supported restorations [15,16,17].
To minimize prosthetic complications, the use of a conical locking implant–abutment connection is recommended [18]. This connection is based on the ‘cold welding’ principle, whereby high contact pressure and friction resistance between the implant and abutment secure the interface [19].
One of the earliest clinical studies on implants with conical locking connections was published by Chapman and Grippo in 1996. In a retrospective study of 1757 implants with conical locking connections across three centers, nine abutment fractures (0.05%) and thirty instances of abutment loosening (1.7%) were reported [20].
In 2001, Mangano and Bartolucci reported on a clinical study using Mac System Implants (Cabon, Milan, Italy) with conical locking connections. In this study, 80 single-tooth implant restorations were placed in 69 patients. Osseointegration failed in two implants, and peri-implantitis was observed in one implant. Additionally, two abutment fractures and one case of abutment loosening were noted during the restorative process, yielding a mechanical complication rate of 3.75% over a 3.5-year observation period [21].
Mangano reported that in a five-year follow-up of bar-retained prostheses made with Leone implants featuring conical locking connections, no mechanical complications occurred at the implant–abutment interface. However, twelve loosenings of retaining clips, two retaining clip fractures, two acrylic denture base fractures, two acrylic tooth fractures, and three gold bar fractures were reported [22].
In a study conducted by Demirekin [12], 239 NTA implants placed in 99 patients were observed over a two-year period. The most common prosthetic complication was a veneer ceramic fracture, which occurred at a rate of 3.6%, and chipping rates for 175 crowns ranged from 3.2% to 25.5%. The overall complication rate over a five-year follow-up period was recorded as 3.5%. Ceramic veneers, known for their lower fracture strength, have reported chipping rates of 1.8% for alumina veneers and 3.5% for lithium disilicate ceramics over five years, while ceramic crowns with zirconium substructures exhibited significantly higher chipping rates (11.8%). In contrast, metal–ceramic crowns have shown a chipping rate of 3.5% [16].
Several studies have compared external and internal implant connection types with various designs [23].
In an in vitro study evaluating the mechanical evaluation of screw and conical interlocking connection types, a high rate of mechanical complications was observed in implant systems with screwed connection mechanisms, especially in external hexagonal implants placed in place of single teeth, while abutment loosening was reported to be less likely in conical interlocking implants [19].
In our study, where we evaluated implant-supported prosthetic restorations with screw and conical locking connections, 18 (21.68%) of the complications were determined to be retention losses, 19 (22.89%) were cases of screw loosening, 21 (25.30%) were veneer ceramic fractures, three (3.61%) were acrylic base fractures, 14 (16.87%) were cases of peri-implantitis, and eight (9.64%) were implant losses. When the distribution of complications that occurred in screw-connected implant-supported prosthetic restorations was examined, eight (9.64%) retention losses, 15 (18.07%) screw loosenings, eight (9.64%) veneer ceramic fractures, one (1.20%) acrylic base fracture, four (4.82%) cases of peri-implantitis, and two (2.41%) implant losses were determined. When the distribution of complications that occurred in implant-supported prosthetic restorations with conical locking connections was examined, nine (10.84%) retention losses, four (4.82%) screw loosenings, six (7.23%) veneer ceramic fractures, two (2.41%) acrylic base fractures, four (4.82%) cases of peri-implantitis, and six (7.23%) implant losses were determined. When the distribution of complications that occurred in implant-supported prosthetic restorations, including both screw-fixed and conical locking implant types, was examined, one (1.20%) retention loss, seven (8.43%) veneer ceramic fractures, and six (7.23%) cases of peri-implantitis were determined.
When complications were classified as repairable versus irreparable, implant losses (irreparable complications) were more common in conical locking implants. Specifically, failure occurred in the group combining conical locking and screw-retained implants, as well as in two implants from the screw-retained group, out of a total of 579 implants placed in 137 patients. Among the repairable complications, screw loosening was the most prevalent, with an overall rate of 22.89%, and it was observed more frequently in screw-retained implants.
Furthermore, some studies have investigated the effect of the implant–abutment connection design on marginal bone loss [24].
Canullo et al. [25] reported that the abutment connection design may affect bacterial activity levels at the implant–abutment interface. Maeda et al. [26] suggested that internal hexagonal-type implants exhibited a broad force distribution, whereas external hexagonal-type implants increased the stress concentration in the cervical region. This suggests that factors that differ among abutment connection types contribute to marginal bone loss.
Canullo et al. suggested that marginal bone loss can be measured from a standard reference point at the implant neck [27]. In a retrospective study, 600 implants from 151 patients were evaluated to examine long-term marginal bone loss. Loss was detected in 23 implants after occlusal loading [28].
In another study conducted in 2024, a total of 301 implants in 69 patients were evaluated. At 22 ± 10.7 months of follow-up after prosthetic loading, the marginal bone loss level was observed to be ≤1.5 mm for all implants [29].
A separate 2024 study compared implant-supported prosthetic restorations fabricated as metal–ceramic and monolithic zirconia superstructures over a 5-year period. In the metal–ceramic group, chipping was observed in seven restorations and abutment screw loosening in two restorations, whereas the monolithic zirconia group experienced chipping in seven restorations. Notably, marginal bone loss was significantly higher in the metal–ceramic group (1.21 ± 0.23 mm) than in the monolithic zirconia group (0.22 ± 0.14 mm; p < 0.001). No major mechanical complications (e.g., implant or substructure fractures) were observed in either group [30].
In another study conducted in 2024, 25 implants were applied in 25 patients. No significant difference was observed in the evaluation of one-year and two-year marginal bone losses (p = 0.096) [31].
In another study conducted in 2023, 671 implants and 2238 implants with prosthetic restorations without cantilevers were evaluated. A slow and progressive increase in marginal bone loss was observed over time [32].
In a study conducted in 2023, 166 implants were evaluated in 100 patients who received externally connected implants. In this study, which had an average observation period of 43 months, the average distal marginal bone loss was 0.20 mm [33].
In our study, the evaluation criteria of Albrektsson and Zarb regarding vertical bone loss were taken as the basis for the radiographic examinations. Bone loss of up to 1.5 mm in the first year after functional loading and bone loss of up to 0.2 mm for each subsequent year is considered normal [34].
In our study, when the values of mesial marginal bone loss and distal marginal bone loss variables in both the conical locking connection and screw-fixed implant groups were compared within themselves at the 12th month, 24th month, 36th month, 48th month, and 60th month, a significant difference was found between the values of marginal bone loss variables (p < 0.001). When the values of marginal bone loss variables were compared between the conical locking connection and screw-fixed implant groups according to time, a significant difference was found between the two groups (p < 0.001). When the values of the mesial marginal bone loss variables and the values of the distal marginal bone loss variables of all implants followed over time were compared, no significant difference was found (p > 0.05). When the values of the mesial marginal bone loss and distal marginal bone loss variables were compared between the conical locking connection implant and screw-fixed implant groups over time, no significant difference was found (p > 0.05). In our study, the mesial and distal marginal bone losses in the conical locking connection implant and screw-fixed implant groups progressed progressively in parallel with time in each subsequent year of follow-up.
The limitations of this study are as follows:
This study was conducted in a single center and by a single prosthodontist and jaw surgeon;
A larger number of implants and patients were included in this study;
This study was followed for a longer period of time.
5. Conclusions
Based on the 60-month retrospective evaluation results of the 579 implants and 242 restorations applied, the following conclusions can be drawn:
1. Among the 579 conical locking connection and screw-retained implants placed in a total of 137 patients, failure was observed in six conical locking connection implants and two screw-retained implants;
2. The evaluation of the prosthetic treatment success of conical locking connection and screw-retained implants revealed that the success rate of implant-supported prosthetic restorations with conical locking connection implants was higher than that of screw-retained implant-supported prosthetic restorations;
3. No significant differences were found in the values of mesial and distal marginal bone loss variables for conical locking connection implants within each year. However, significant differences were detected in the values of mesial and distal marginal bone loss variables for screw-retained implants within each year;
4. In this study, mesial and distal marginal bone loss in both the conical locking connection and screw-retained implant groups progressed progressively over time during each annual follow-up period.
Author Contributions
Conceptualization, S.S.T. and Z.B.D.; methodology, S.S.T.; software, E.A.; validation, S.S.T., Z.B.D. and E.A.; formal analysis, E.A.; investigation, E.A.; resources, E.A.; data curation, E.A.; writing—original draft preparation, Z.B.D. and E.A.; writing—review and editing, Z.B.D.; visualization, Z.B.D.; supervision, S.S.T.; project administration, S.S.T.; funding acquisition, Z.B.D. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by NTA IMPLANT GRUP SAN. TIC. A.S.
Institutional Review Board Statement
The study was approved by the Süleyman Demirel University Clinical Research Ethics Committee with the decision numbered 191 dated 7 July 2022.
Informed Consent Statement
Written informed consent has been obtained from the patients to publish this paper.
Data Availability Statement
Research data can be available from the corresponding author and obtained in the article.
Conflicts of Interest
The authors declare no conflict of interest.
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Table 1.
Inclusion and exclusion criteria for patients selected for this study.
| Patient Selection Criteria for the Study | Exclusion Criteria for Patients |
|---|---|
| Patients without systemic disease; Patients not younger than 18 years old; Patients with good oral hygiene; Patients without any signs of bruxism; Patients without alcohol addiction; Individuals who smoke fewer than 10 cigarettes per day; Individuals who have not received radiotherapy or chemotherapy; No pathology observed in hard and soft tissues during routine clinical and radiographic examinations; Patients who have completed the planned surgical and prosthetic treatment protocol and agreed to come for regular check-ups. |
|
Table 2.
Distribution of patients’ demographic information.
| Conical Lock Connection | Screw Connection | Both Conical Lock Connection and Screw Connection | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|
| N | % | N | % | N | % | N | % | ||
| Gender | Female | 21 | 26.58 | 47 | 59.49 | 11 | 13.92 | 79 | 57.66 |
| Male | 10 | 17.24 | 39 | 67.24 | 9 | 15.51 | 58 | 42.33 | |
| Age | 23–39 | 2 | 6.45 | 10 | 11.62 | 2 | 10.00 | 14 | 10.21 |
| 40–59 | 20 | 64.51 | 35 | 40.69 | 8 | 40.00 | 63 | 45.98 | |
| 60 and above | 9 | 29.03 | 41 | 47.67 | 10 | 50.00 | 60 | 43.79 | |
| Number of Implants | Maxilla | 52 | 17.50 | 159 | 53.53 | 86 | 28.95 | 297 | 51.30 |
| Mandible | 47 | 16.66 | 159 | 56.38 | 76 | 26.95 | 282 | 48.70 | |
Table 3.
Distribution of implant-supported prosthetic restoration types.
| Conical Lock Connection | Screw Connection | Both Conical Lock Connection and Screw Connection | Total | |||||
|---|---|---|---|---|---|---|---|---|
| N | % | N | % | N | % | N | % | |
| Single Crown | 7 | 13.21 | 31 | 17.61 | 0 | 0 | 38 | 15.70 |
| Fixed Partial Cemented Bridge Restoration | 42 | 79.25 | 89 | 50.57 | 5 | 38.46 | 136 | 56.19 |
| Fixed Section Screw Retained Bridge Restoration | 2 | 3.77 | 43 | 24.43 | 8 | 61.54 | 53 | 21.90 |
| Overdenture Prosthesis | 2 | 3.77 | 13 | 7.39 | 0 | 0 | 15 | 6.19 |
Table 4.
Distribution according to implant-supported prosthetic restoration materials.
| Conical Lock Connection | Screw Connection | Both Conical Lock Connection and Screw Connection | Total | |||||
|---|---|---|---|---|---|---|---|---|
| N | % | N | % | N | % | N | % | |
| Metal–Ceramic Restorations | 46 | 88.46 | 155 | 88.07 | 12 | 85.71 | 213 | 88.01 |
| Zirconium-Based Ceramic Restorations | 3 | 5.77 | 6 | 3.41 | 2 | 14.29 | 11 | 4.55 |
| Metal–Acrylic Resin Restorations | 3 | 5.77 | 15 | 8.52 | 0 | 0 | 18 | 7.44 |
Table 5.
Distribution according to implant-supported prosthetic restoration complications.
| Conical Lock Connection | Screw Connection | Both Conical Lock Connection and Screw Connection | Total | |||||
|---|---|---|---|---|---|---|---|---|
| N | % | N | % | N | % | N | % | |
| Loss of Retention | 9 | 10.84 | 8 | 9.64 | 1 | 1.20 | 18 | 21.68 |
| Screw Looseness | 4 | 4.82 | 15 | 18.07 | 0 | 0 | 19 | 22.89 |
| Screw Fracture | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Veneer Ceramic Fracture | 6 | 7.23 | 8 | 9.64 | 7 | 8.43 | 21 | 25.30 |
| Fixed Infrastructure Fracture | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Moving Infrastructure Fracture | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Acrylic Base Broken | 2 | 2.41 | 1 | 1.20 | 0 | 0 | 3 | 3.61 |
| Peri-implantitis | 4 | 4.82 | 4 | 4.82 | 6 | 7.23 | 14 | 16.87 |
| Loss of Implants | 6 | 7.23 | 2 | 2.41 | 0 | 0 | 8 | 9.64 |
| Total | 31 | 37.35 | 38 | 45.78 | 14 | 16.86 | 83 | 100 |
Table 6.
Comparison of the mesial and distal marginal bone loss of implants (conical locking connection and screw connection) applied to patients.
Table 6.
Comparison of the mesial and distal marginal bone loss of implants (conical locking connection and screw connection) applied to patients.
| Group | Average | Std. Deviation | N | p | ||
|---|---|---|---|---|---|---|
| Implant with conical locking connection | Distal | 12 months | 0.59866 | 0.32982 | 153 | <0.001 |
| 24 months | 0.71146 | 0.41525 | 153 | |||
| 36 months | 1.37919 | 0.74845 | 153 | |||
| 48 months | 1.61049 | 0.84415 | 148 | |||
| 60 months | 1.85767 | 0.93492 | 148 | |||
| Mesial | 12 months | 0.51233 | 0.31872 | 153 | <0.001 | |
| 24 months | 0.68760 | 0.47165 | 153 | |||
| 36 months | 1.33459 | 0.80231 | 153 | |||
| 48 months | 1.56438 | 0.87077 | 148 | |||
| 60 months | 1.78570 | 0.97907 | 148 | |||
| Screw-fixed implant | Distal | 12 months | 0.54638 | 0.34536 | 426 | <0.001 |
| 24 months | 0.90553 | 0.59196 | 426 | |||
| 36 months | 1.45194 | 1.06266 | 426 | |||
| 48 months | 1.69421 | 1.19892 | 426 | |||
| 60 months | 1.92757 | 1.28231 | 424 | |||
| Mesial | 12 months | 0.56743 | 0.25364 | 426 | <0.001 | |
| 24 months | 0.84118 | 0.48184 | 426 | |||
| 36 months | 1.34287 | 1.01495 | 426 | |||
| 48 months | 1.54429 | 1.11494 | 426 | |||
| 60 months | 1.73708 | 1.16848 | 424 | |||
Table 7.
Comparison of marginal bone loss data over time for conical locking and screw-retained implants.
Table 7.
Comparison of marginal bone loss data over time for conical locking and screw-retained implants.
| Time | Group | Average | Std. Deviation | N | p | |
|---|---|---|---|---|---|---|
| 12 months | Implant with conical locking connection | Distal | 0.71146 | 0.41525 | 148 | 0.646 |
| Mesial | 0.68760 | 0.47165 | 148 | |||
| Total | 0.69953 | 0.44375 | 296 | |||
| Screw-fixed implant | Distal | 0.90553 | 0.59196 | 425 | ||
| Mesial | 0.84118 | 0.48184 | 425 | |||
| Total | 0.87335 | 0.54035 | 850 | |||
| Total | Distal | 0.85540 | 0.55793 | 573 | ||
| Mesial | 0.80151 | 0.48352 | 573 | |||
| Total | 0.82846 | 0.52252 | 1146 | |||
| 24 months | Implant with conical locking connection | Distal | 1.37919 | 0.74845 | 148 | |
| Mesial | 1.33459 | 0.80231 | 148 | |||
| Total | 1.35689 | 0.77485 | 296 | |||
| Screw-fixed implant | Distal | 1.45194 | 1.06266 | 425 | ||
| Mesial | 1.34287 | 1.01495 | 425 | |||
| Total | 1.39740 | 1.03990 | 850 | |||
| Total | Distal | 1.43315 | 0.99098 | 573 | ||
| Mesial | 1.34073 | 0.96386 | 573 | |||
| Total | 1.38694 | 0.97818 | 1146 | |||
| 36 months | Implant with conical locking connection | Distal | 1.61049 | 0.84415 | 148 | |
| Mesial | 1.56438 | 0.87077 | 148 | |||
| Total | 1.58743 | 0.85642 | 296 | |||
| Screw-fixed implant | Distal | 1.69421 | 1.19892 | 425 | ||
| Mesial | 1.54429 | 1.11494 | 425 | |||
| Total | 1.61925 | 1.15944 | 850 | |||
| Total | Distal | 1.67259 | 1.11802 | 573 | ||
| Mesial | 1.54948 | 1.05660 | 573 | |||
| Total | 1.61103 | 1.08901 | 1146 | |||
| 48 months | Implant with conical locking connection | Distal | 1.85767 | 0.93492 | 148 | |
| Mesial | 1.78570 | 0.97907 | 148 | |||
| Total | 1.82168 | 0.95631 | 296 | |||
| Screw-fixed implant | Distal | 1.92757 | 1.28231 | 425 | ||
| Mesial | 1.73708 | 1.16848 | 425 | |||
| Total | 1.83233 | 1.22969 | 850 | |||
| Total | Distal | 1.90952 | 1.20185 | 573 | ||
| Mesial | 1.74964 | 1.12199 | 573 | |||
| Total | 1.82958 | 1.16485 | 1146 | |||
| 60 months | Implant with conical locking connection | Distal | 1.94637 | 1.24352 | 148 | |
| Mesial | 1.89675 | 1.12353 | 148 | |||
| Total | 1.93843 | 1.12435 | 296 | |||
| Screw-fixed implant | Distal | 2.12736 | 1.32425 | 425 | ||
| Mesial | 1.83736 | 1.25342 | 425 | |||
| Total | 1.93733 | 1.23415 | 850 | |||
| Total | Distal | 2.14232 | 1.35422 | 573 | ||
| Mesial | 1.89252 | 1.24352 | 573 | |||
| Total | 1.93753 | 1.25342 | 1146 |
Table 8.
Evaluation of marginal bone loss in the first year and the next four years after prosthetic restoration.
Table 8.
Evaluation of marginal bone loss in the first year and the next four years after prosthetic restoration.
| Conical Locking Implants | p | Screw-Anchored Implants | p | |||||
|---|---|---|---|---|---|---|---|---|
| N | % | N | % | |||||
| 12 months | Mesial | 1.5 mm< | 143 | 93.5 | 0.627 | 406 | 95.3 | 0.004 |
| 1.5 mm> | 10 | 6.5 | 20 | 4.7 | ||||
| Distal | 1.5 mm< | 145 | 94.8 | 384 | 90.1 | |||
| 1.5 mm> | 8 | 5.2 | 42 | 9.9 | ||||
| 24 months | Mesial | 1.5 mm< | 143 | 93.5 | 0.627 | 406 | 95.3 | 0.004 |
| 1.5 mm> | 10 | 6.5 | 20 | 4.7 | ||||
| Distal | 1.5 mm< | 145 | 94.8 | 384 | 90.1 | |||
| 1.5 mm> | 8 | 5.2 | 42 | 9.9 | ||||
| 36 months | Mesial | 0.2 mm< | 21 | 13.7 | 0.607 | 237 | 55.6 | 0.000 |
| 0.2 mm> | 132 | 86.3 | 189 | 44.4 | ||||
| Distal | 0.2 mm< | 18 | 11.8 | 170 | 39.9 | |||
| 0.2 mm> | 135 | 88.2 | 256 | 60.1 | ||||
| 48 months | Mesial | 0.2 mm< | 84 | 56.8 | 1.000 | 300 | 70.4 | 0.000 |
| 0.2 mm> | 64 | 43.2 | 126 | 29.6 | ||||
| Distal | 0.2 mm< | 84 | 56.8 | 230 | 54.0 | |||
| 0.2 mm> | 64 | 43.2 | 196 | 46.0 | ||||
| 60 months | Mesial | 0.2 mm< | 85 | 57.4 | 0.483 | 272 | 64.1 | 0.000 |
| 0.2 mm> | 63 | 42.6 | 152 | 35.9 | ||||
| Distal | 0.2 mm< | 79 | 53.4 | 204 | 48.1 | |||
| 0.2 mm> | 69 | 46.6 | 220 | 51.9 | ||||
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MDPI and ACS Style
Altinbas, E.; Türkaslan, S.S.; Başağaoğlu Demirekin, Z. Evaluation of Complications and Marginal Bone Loss Observed in Prosthetic Restorations Applied to Different Implant Abutment Connection Types: A Retrospective Study. Prosthesis 2025, 7, 46. https://doi.org/10.3390/prosthesis7030046
AMA Style
Altinbas E, Türkaslan SS, Başağaoğlu Demirekin Z. Evaluation of Complications and Marginal Bone Loss Observed in Prosthetic Restorations Applied to Different Implant Abutment Connection Types: A Retrospective Study. Prosthesis. 2025; 7(3):46. https://doi.org/10.3390/prosthesis7030046
Chicago/Turabian StyleAltinbas, Elif, Serhat Süha Türkaslan, and Zeynep Başağaoğlu Demirekin. 2025. "Evaluation of Complications and Marginal Bone Loss Observed in Prosthetic Restorations Applied to Different Implant Abutment Connection Types: A Retrospective Study" Prosthesis 7, no. 3: 46. https://doi.org/10.3390/prosthesis7030046
APA StyleAltinbas, E., Türkaslan, S. S., & Başağaoğlu Demirekin, Z. (2025). Evaluation of Complications and Marginal Bone Loss Observed in Prosthetic Restorations Applied to Different Implant Abutment Connection Types: A Retrospective Study. Prosthesis, 7(3), 46. https://doi.org/10.3390/prosthesis7030046
