Treatment Modalities for Overdentures on Screw-Retained Bars on Implants

Jimoh Olubanwo Agbaje1 and Henri Diederich2*
1OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, Catholic University Leuven, Belgium
2Doctor in dental medicine, 114 av de la Faiencerie, L- 1511 Luxembourg
*Corresponding author: Henri Diederich, Doctor in dental medicine, 114 av de la Faiencerie, L- 1511 Luxembourg
Citation: Agbaje JO and Diederich H, Treatment Modalities for Overdentures on Screw-Retained Bars on Implants. J Oral Med and Dent Res. 6(1):1-18.
Received: January 18, 2025 | Published: January 26, 2025
Copyright© 2025 genesis pub by Agbaje JO, et al. CC BY-NC-ND 4.0 DEED. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International License. This allows others distribute, remix, tweak, and build upon the work, even commercially, as long as they credit the authors for the original creation.
DOI: https://doi.org/10.52793/JOMDR.2025.6(1)-92
Abstract
Implant overdentures offer a practical and effective solution for edentulous patients with limited bone volume or contraindications for grafting. These cases demonstrate the successful use of both flapless and open flap implant techniques for overdenture rehabilitation, with the added benefit of immediate loading in the mandible. The combination of high primary stability, optimized thread design, and proper load distribution creates a favorable environment conducive to successful early loading.
Keywords
Rehabilitation in atrophied bone; Overdenture; Screw-retained bars; Palatal approach; Compressive Implants; Minimally invasive implant treatment options in mandible and maxilla.
Introduction
Full-arch rehabilitation for the maxilla and mandible using fixed implant-supported prostheses offers superior function, prosthetic stability, and enhanced quality of life. However, these treatments are often cost-prohibitive, making them inaccessible for many patients [1,2].
Implant overdentures present a more affordable alternative, providing improved function and stability with the use of two or more implants for retention. Unlike fixed full-arch restorations, implant overdentures are relying primarily on soft-tissue for support and can be removed by the patient for routine hygiene purposes [3,4,5].
Challenges in Implant Overdenture Cases
Patients considering implant overdentures frequently exhibit insufficient bone width in the residual alveolar ridge, especially in the maxilla. Bone grafting is often necessary to facilitate implant placement when only conventional implants are available [6]. However, grafting procedures may not always be feasible due to health, age, or financial limitations [7].
Compressive Implants: A Novel Solution
The following case reports demonstrate compressive implants with compressive thread designs (ROOTT implants R, P, M, and MS, Trate AG). These implants provide enhanced primary stability and retention in cases with limited bone volume. In the maxilla and in the mandible, these implants can be placed in bone widths as narrow as 4 mm, while in the mandible, they allow for early loading, with prosthesis delivery possible within three weeks using either a flapless or open-flap surgical technique. For maxillary overdentures, delayed loading is generally recommended [8,9].
Conditions for successful early loading with ROOTT compressive implants in bar-supported prosthetics
The success of early loading with ROOTT compressive implants relies on achieving both primary and secondary stability. Primary stability refers to the mechanical stability achieved immediately after implant placement, while secondary stability develops through biological osseointegration, typically within the first 100 days of healing.
Pioneering studies conducted in the 1980s highlighted the long-term efficacy of compressive implants. Ledermann (1983) and Ledermann, Kallenberger, Rahn, and Steinemann (1985) demonstrated that this type of implant could achieve permanent fixation in bone over several years. Similarly, Tetsch [10]. emphasized the importance of implant design in ensuring stable outcomes.
Critical Factors for Success
Key elements that contribute to the success of compressive implants for early loading in the mandible include:
- Compressive implants feature a thread design that minimizes undesirable shearing forces on the surrounding jawbone.
- The compressive action optimally distributes stress, which prevent damage to the bone tissue.
- The self-tapping nature of the threads enhances the anchorage of the implant within the bone.
- This design promotes strong mechanical stability, which is essential for early loading.
- High primary stability is further enhanced when multiple implants are rigidly connected using a bar passively.
- This configuration neutralizes shear and torsional forces, thereby creating favourable conditions for osseointegration.
Indications for Implant Overdentures
Although fixed restorations offer superior function and stability, implant overdentures are particularly suitable in the following scenarios:
- When insufficient bone volume prevents optimal implant positioning for achieving adequate anterior-posterior (A-P) spread for a fixed restoration [11,12].
- When bone augmentation is required for fixed restorations, however the patient is ineligible due to systemic health issues, advanced age, or financial constraints [13,14].
- Patients preferring removable prostheses, but experience retention issues can benefit from implant overdentures whilst maintaining the aesthetics of traditional dentures [15,16].
- Implant overdentures designed with a horseshoe-shaped configuration improve comfort, speech, and taste perception for patients that desire a palataless prosthesis [17,18,16].
Historical Perspective
The concept of bar-retained overdentures on implants dates to 1975, when Philippe D. Ledermann first described their use with crystalline bone screws (CBS) developed by Sandhaus [19]. By 1977, titanium plasma spray (TPS)-coated screws were introduced which further advance the technique [19].
- 1975: Ledermann’s CBS implants for mandibular overdentures.
- 1986: Publication of comprehensive guidelines for TPS screw implants by Ledermann (Quintessenz) [20].
- 1996: Over 20 years of successful outcomes with bar-retained overdentures in the mandible reported by Ledermann [21].
Benefits of Bar-Retained Overdentures
- Bar-retained overdentures are firmly anchored to implants, providing superior stability compared to traditional removable dentures [22,23].
- These overdentures reduce irritation and soreness, thereby offer a more comfortable fit for patients [24,25].
- Implants stimulate the jawbone, preserve bone density and prevent resorption, thereby contributing to long-term oral health [26,27].
- With proper care, bar-retained overdentures demonstrate excellent durability, they require fewer adjustments than conventional dentures [28].
- The secure fit of bar-retained overdentures eliminates the movement typical of traditional dentures, this enhances functionality and patient satisfaction [29].
Case Report 1: Screw-Retained Bar Rehabilitation
The patient, a 63-year-old male, presented with dissatisfaction regarding his maxillary removable prosthesis due to poor retention and lack of stability. Clinical and radiographic assessments showed insufficient bone width (approximately 4 mm) in the maxilla. Traditional implant placement would have required a bone grafting procedure to achieve adequate bone volume for rehabilitation, which the patient wished to avoid.
A practical solution was achieved using One-Piece Tissue-Level ROOTT S implants, without the need of bone grafting. These implants provided effective stabilization and retention of the prosthesis, successfully addressing the patient’s concerns. Following a thorough radiographic evaluation, ROOTT S 3.0/16 mm implants (Figure 1) were selected for the procedure.
Figure 1: ROOTT S 3.0/16 mm.
Surgery was performed using an open-flap approach (Figure 2), and the implants were successfully placed. During insertion, a high primary stability was achieved, with torque values reaching approximately 50 N/cm.
Figure 2: Narrow bone width.
After implant placement (figure 3), the surgical site was closed with sutures, healing caps was omitted to allow the patient to be able to wear the existing prosthesis over the implants.
Figure 3: Implant placement in maxillae.
After a healing period of four months, the surgical site was reopened, and impressions taken with screw-retained transfer copings (figure 4a and b) an open tray technique was used.
Figure 4A: Screw-retained transfer copings. B: Impression taken with open tray technique.
Following the impression procedure, healing caps were placed on the implants. During the second appointment, a verification jig was used to confirm the accuracy of the implant positions (Figure 5), and the patient's bite was recorded and adjusted as necessary (Figure 6).
Figure 5A: Verification jig. B: Verification jig in the mouth.
Figure 6: Bite plate and wax for bite record.
At the third appointment, the milled bar (Figure 7) and the provisional overdenture were evaluated for fit and function.
Figure 7: Milled bar.
During the fourth appointment, the bar was fixed on the implants, and the final overdenture was delivered to the patient (Figure 8).
Figure 8A: Soft tissue before bar placement, B: fixed bar in the mouth, C: the final prosthesis.
The bar was securely screwed onto the implants with a torque of 15 N/cm. The overdenture was delivered and securely retained on the bar, which provide optimal stability and function. (Figure 9) show clinical and radiological image after completion of treatment.
9A B
C
Figure 9 (A-C): show clinical and radiological images after placement.
An alternative to the above treatment approach, in the absence of these specialized implants, would involve a bone graft procedure, as demonstrated in the accompanying illustration (Figures 10 -13).