LOCATOR FIXED® represent a significant advancement in dental prosthetics. This system utilizes precision attachments that secure prosthetic restorations onto dental implants, providing the stability of fixed restorations without the associated high costs. The benefits extend beyond affordability, encompassing enhanced stability and improved retention compared to removable alternatives³.

In this case report, we showcase the positive impact of LOCATOR FIXED® on a patient facing severe worn dentition and posterior bite collapse. Despite the need for a fixed solution for both upper and lower jaws, the patient had limited financial resources. Straumann® BLX implants were strategically placed in the mandibular arch, and the restoration of esthetics, phonetics, and function was achieved through a combination of a maxillary conventional denture and a mandibular LOCATOR FIXED® prosthesis. The successful completion of this case involved the integration of both analog and digital workflows. The treatment with LOCATOR FIXED® not only effectively restored oral function, but also revitalized the patient's confidence. This case highlights the significant influence of affordable fixed options in prosthodontic care.

Initial situation

A 65-year-old female in good systemic health and with no medical conditions that contraindicate dental treatment presented to our clinic with a chief complaint of “I can’t chew my food properly”. She reported sensitivity of her anterior teeth to cold and during chewing. Her dental history revealed multiple extractions as a result of caries and periodontal disease. She wanted to improve the esthetics of her smile and expressed a desire for a fixed solution due to the hopeless condition of her dentition.

During the extra-oral examination in a relaxed state, there was evident drooping of the corners of the lips (Fig. 1). The smile displayed noticeable wear on the upper front teeth, and the profile appeared straight. The patient exhibited a short facial type, marked by a reduction in the height of the lower third of the face (Figs. 2,3).

The intraoral examination showed severe wear of all remaining anterior dentition and loss of multiple upper posterior and all lower posterior dentition. In addition, a supra-eruption of the maxillary posterior teeth was observed (Fig. 4). In centric relation, initial contact was identified in the #23/33 teeth (Fig. 5).

The patient showed a hit-and-slide phenomenon upon reaching centric occlusion, resulting in a severe pseudo-Class III condition, with accompanying splaying of the anterior teeth and collapse of vertical dimension (Figs. 6,7). Furthermore, space was inadequate for posterior restorations. Oral hygiene was fair.

The preoperative radiographic analysis, conducted prior to the surgical intervention (Panoramic X-ray and Cone Beam Computed Tomography), depicted inadequate quality and quantity of bone in the maxillary arch to consider a treatment with dental implants. On the other hand, the osseous volume in the mandibular arch supported the placement of implants for either a fixed or removable implant-supported prosthesis. A periapical radiolucency was evident at the apex of tooth #25.

In managing this case, our treatment strategy integrated both digital and analog workflows, enhancing communication between clinicians, the implant team, and patients. Conventional methods, including taking traditional impressions, were incorporated. Moreover, occlusal wax rims were utilized to establish the vertical dimension, determine the occlusal plane's position, and capture centric relation, as well as for space analysis (Figs. 9,10).

Subsequently, a set-up was performed at the clinically determined Vertical Dimension of Occlusion (VDO). This involved preserving the lower anterior teeth to facilitate the integration of Cone Beam Computed Tomography (CBCT) and Stereolithography (STL) files. This integrated approach was strategically employed for surgical planning and the fabrication of a surgical guide (Figs. 11-13).

The following step entailed scanning the dental models, resulting in the creation of STL files. These STL files were then integrated with Cone Beam Computed Tomography (CBCT) Digital Imaging and Communications in Medicine (DICOM) files. The purpose of this integration was to fuse the detailed anatomical information from the CBCT scans with the digital representation of the dental models obtained from the STL files. This merging process significantly enhances our diagnostic capabilities, providing a comprehensive dataset instrumental for optimal treatment planning, virtual simulations, and the fabrication of precise surgical guides.

Treatment planning

Following a comprehensive assessment of the case through both analog and digital means, and on completion of the prosthetically driven surgical planning, the patient was informed that the long-term prognosis of her dentition was highly questionable and that maintaining it would require a collaborative approach involving a periodontist, endodontist, orthodontist, prosthodontist, and oral surgeon. Various options, including fixed and removable implant-supported solutions, were presented alongside the possibility of full mouth extraction. The patient, unwilling to preserve her natural teeth, was initially advised to consider an implant supported screw-retained fixed full arch prosthesis. However, she ultimately declined this option, citing financial constraints. Instead, she chose to proceed with a combination of a maxillary conventional denture and a mandibular LOCATOR FIXED® prosthesis.

The goal of the treatment included the restoration of the vertical dimension, the reestablishment of the facial third proportions, the development of a physiologic occlusion in centric relation and the creation of an esthetic smile in harmony with function.

Due to the limited ridge height, elevated floor of the mouth, and insufficient attached tissues, the proposed approach involved converting the lower immediate denture into a screw-retained interim prosthesis. This allows the patient to experience the advantages of a fixed  restoration and provides a protective barrier for the surgical site, mitigating potential trauma associated with a removable interim prosthesis. This adaptation promotes stability, security, and optimal healing, offering a comprehensive solution to the identified challenges.

The main steps of the treatment workflow included:

1. Implant position planning (Fig. 14).

2. Model extraction of anterior teeth to finalize set-up (Fig. 15).

3. Fabrication of upper and lower IvoBase® immediate denture (Figs. 16-17).

4. Extractions and bone grafting.

5. Immediate loading of the prostheses.

6. Three months post surgery: analog impressions (Fig. 18).

7. Final esthetic wax try-in and design

8. LOCATOR FIXED® housing pick-up sequence.

9. Delivery of final prostheses.

Surgical procedure

In the surgical phase of the case, Dr. Michael Shapiro extracted the remaining maxillary and mandibular teeth and performed a maxillary tuberosity reduction.

The patient was given a preoperative dose of antibiotics and her mouth was rinsed with oral chlorhexidine. The patient was then sedated with intravenous midazolam and propofol, a full-thickness mandibular flap was elevated and the remaining maxillary and mandibular teeth were removed. A maxillary tuberosity reduction was performed. The mandibular CT surgical guide was secured per protocol and four Straumann® BLX, Roxolid®, SLActive® implants were precisely placed in the mandibular arch between the mental foramina. For the immediate temporary prosthesis, straight SRA abutments were then seated and torqued to 35 Ncm. Temporary cylinders were employed to connect a prefabricated immediate denture to the SRA abutment. Subsequently, the flanges were removed, and the fixed prosthesis was delivered and secured with prosthetic screws torqued to 15 Ncm.

Prosthetic procedure

After a 3-month healing period, the surgical prosthesis was removed, and a two-step closed tray preliminary impression was taken onto which an impression jig and a custom tray were fabricated. During the subsequent appointment, the impression jig was reassembled using dual-cure resin, and an open tray fixture-level impression was taken to create a master model.

Subsequent appointments were used to determine the vertical dimension of occlusion (VDO), acquiring a Kois facebow, and recording a bite registration. An esthetic wax try-in was completed and, after thorough consultation with the patient, who expressed satisfaction with the fixed option during the healing phase, the decision was to proceed with a LOCATOR FIXED® prosthesis.

In the pursuit of precision to specific criteria, the laboratory procedures for this case underwent a series of meticulous instructions outlined in the Laboratory Work Authorization. The mandibular set-up and design of the LOCATOR FIXED® prosthesis were initiated by scanning, with careful measurement of the AP spread to ensure distal extensions do not exceed 1x the AP spread. Precision was further enhanced by designing struts extending from the prosthetic to the buccal and lingual land areas, facilitating precise positioning during the pick-up of the LOCATOR FIXED® housings. A Digital Design Review Meeting was scheduled to collaboratively discuss the digital design before the milling process, confirming accuracy. Subsequent steps involved occlusion adjustment, tissue shading, LOCATOR FIXED® housing pick-up, and pink tissue simulation (Figs. 19-20).

During this process, detailed information of the implants was provided region 21 (⌀4.0 x 10mm), region 24 (⌀4.0 x 12mm), region 25 (⌀5.0 x 12mm) and region 28 (⌀4.5 x 10mm). These comprehensive and detailed instructions served as a guiding framework for the laboratory, ensuring the accurate execution of prosthetic work and alignment of the outcome with the specified criteria.

For LOCATOR FIXED® prostheses, material options include monolithic zirconia (strong, durable), framework-reinforced processed acrylic (lightweight, cost-effective), Ivotion® (monolithic, digital precision), and digital denture "two piece" (customizable, digital efficiency). The choice depends on factors like strength, esthetics, and cost, with clear communication ensuring the material meets both functional and esthetic expectations.

The selected material for the LOCATOR FIXED® prosthesis was a milled Ivotion® Dent. This choice aligns with the benefits of digital precision, monolithic design, and the lightweight properties associated with Ivotion® (Fig. 21). The milled Ivotion® Dent material was expected to provide both functional and esthetic advantages for the specific requirements of the prosthetic restoration.

The sequence for picking up LOCATOR FIXED® housings involved a specific set of steps, including the seating verification struts. This includes verifying and ensuring the accurate placement and seating of the struts associated with the LOCATOR FIXED® housing (Figs. 22,23). This crucial step is essential to confirm proper alignment, stability, and functionality, ensuring the success of the housing pick-up process in the fabrication of the prosthesis.

In the fabrication of the master model, LOCATOR® abutments with appropriate collar heights were placed on the master model and torqued to 25 Ncm.

The models were sent to the laboratory for scanning and fabrication of a monolithic PMMA prosthesis with seating verification struts to allow indexing of the prosthesis to the master model during the pick-up of the LOCATOR FIXED® housings. Next, we proceeded to verify the complete seating of struts.

Following this verification, we moved on to installing block-out spacers and gold housings with black processing inserts (Figs. 24,25). The LOCATOR FIXED® housings were placed on the master cast, and adjustments were made to the intaglio of the prosthesis to allow passivity during pick-up of the housings.

A green fit checker was applied to assess fit and contact points and confirm the complete seating of verification struts as a final check before progressing to the next stages of prosthesis fabrication (Fig. 26).

Subsequently, a verification process was conducted to ensure the replication of the vertical dimension using an esthetic wax try-in (Fig. 27). The occlusion was adjusted against the upper esthetic wax try-in to confirm occlusion and return to the correct vertical dimension of occlusion. This step involved assessing the wax try-in to confirm that it accurately replicates the intended vertical dimension established for the prosthetic restoration. Verification at this stage ensured that the esthetic and functional aspects aligned with the predetermined specifications before proceeding further in the fabrication process.

After verifying all components, the next steps in fabricating the LOCATOR FIXED® prosthesis involved the creation of cement venting holes (Figs. 28,29).

Following this, a bonding agent was applied to ensure secure adherence of the housing to the prosthesis. The housing was then precisely attached with dual-cure composite adhesive, and the articulator was closed to replicate the occlusion accurately. Photopolymerization was initiated to cure the material and solidify the prosthesis. With the completion of photopolymerization, the pick-up process was finalized, firmly securing the housing onto the prosthesis. The prosthesis underwent meticulous fine finishing procedures to refine its surface texture, ensuring optimal esthetics and comfort. Pink coloration was applied to the prosthesis. This comprehensive process culminated in the creation of the mandibular final LOCATOR FIXED® prosthesis, ready for placement to address the patient's dental needs.

After completing the mandibular final LOCATOR FIXED® prosthesis, the fabrication process proceeded with the IvoBase® processing of the maxillary denture. This involved the finalization and processing of the upper denture using IvoBase®, a method that enhances the precision and fit of the denture. The patient presented for her final appointment, and the upper denture was seated according to traditional prosthodontic principles. The LOCATOR® abutments were seated with a torque of 35 Newton centimeters applied for secure engagement (Fig. 30). The prosthesis was tried in with the black processing inserts in place, and adjustments were made to achieve correct vertical dimension and occlusion. The prosthesis was removed, and the black inserts were replaced with green LOCATOR FIXED® retention inserts. (Figs. 31,32).

Finally, the LOCATOR FIXED® seating tool was employed to seat the prosthesis, ensuring precise alignment and positioning (Fig. 33).

These sequential steps contributed to the accurate placement and alignment of the maxillary denture, ensuring optimal function and stability in conjunction with the previously fabricated mandibular prosthesis. Following the completion of the prosthetic procedures, oral hygiene instructions were provided, and occlusion was checked for further assurance of the treatment's success (Figs. 34-37).

Treatment outcomes

In this case report, the application of LOCATOR FIXED® prostheses yielded favorable treatment outcomes for the patient. Evaluation of esthetics, phonetics, comfort, occlusion, and retention were determined to be excellent, including by the patient. The meticulous treatment planning and digital design resulted in a positive impact in addressing functional and esthetic concerns, ultimately enhancing the patient's oral health and quality of life. The patient was very grateful for the result and the care she received throughout treatment. For the patient, the post-treatment experience revealed enhanced comfort, improved chewing efficiency, and the discreet esthetics of the LOCATOR FIXED® prostheses contributed to heightened self-confidence. Maintenance guidelines were clearly communicated, emphasizing the importance of regular follow-up appointments. The patient was scheduled for 3-monthly follow-up appointments.

The collaborative efforts between the dental professionals and the patient resulted in a successful outcome, combining clinical expertise and patient satisfaction.

Author’s testimonial

The course of treatment for this lovely woman was without complications as the surgeon and I followed a detailed scripted protocol. This was important as, in a full-arch scenario, each sequential step relies on the preceding one, emphasizing the importance of avoiding shortcuts and adhering to fundamental principles of prosthodontics. The patient was cooperative throughout the treatment and very thankful for the outcome. Evaluation at her 3-month control validated that LOCATOR FIXED® is an excellent option for patients who are edentulous or with a hopeless dentition.