Search Results (17)

Background/Objectives: Precise implant positioning is critical for successful prosthetic rehabilitation, particularly in completely edentulous patients where anatomical landmarks are lost. The aim of this study was to assess the accuracy of implant placement in the edentulous maxilla and mandible using computer-assisted planning and a bone-supported stackable surgical guide protocol. Methods: This retrospective clinical study included 15 completely edentulous patients who received a total of 60 implants. A dual-scan protocol was utilized for planning. The surgical protocol involved a base guide fixed to the bone with pins, serving as a rigid foundation for stackable components used for osteotomy and implant insertion. Postoperative CBCT scans were superimposed onto the preoperative plan to calculate angular deviations, 3D linear deviations at the implant neck and apex, and depth deviations. Results: The analysis demonstrated high accuracy with a mean angular deviation of 1.25° ± 0.80°. The mean 3D linear deviation was 0.96 ± 0.57 mm at the implant neck and 1.07 ± 0.56 mm at the apex. Depth deviation showed a mean discrepancy of 0.37 ± 0.58 mm. All measured parameters were statistically significantly lower (p < 0.05) than the pre-established clinical safety thresholds. Conclusions: Within the limitations of this study, the bone-supported stackable surgical guide protocol proved to be a highly accurate method for full-arch rehabilitation. By eliminating mucosal resilience and ensuring rigid fixation, this approach enables predictable implant placement and facilitates the passive fit of screw-retained bar-supported prostheses, representing a reliable alternative to dynamic navigation in daily clinical practice. Full article

Background: The following case report presents the treatment of a patient with severe maxillary atrophy and failing residual dentition. The patient has been diagnosed with stage IV grade C periodontitis, making this case challenging from the very beginning. Methods: The treatment plan was based on collecting and merging digital data: CBCT, a face scan, and an intraoral scan. Due to the advancement of the periodontal disease, the treatment was divided into three stages. The entire process was conducted in a digital manner, based on the concept of prosthetically driven implantology. Additionally, all prosthetic temporaries were planned via digital smile design. Stage I included extracting the residual dentition, placing four implants in the mandible, and the delivery of a 3D-printed upper removable denture. Stage II included placing two zygomatic implants, two anchored piriform rims, and one midline implant. Both arches were immediately loaded with the intraoral welding of abutments screwed to multiunit abutments and 3D-printed shells. Subsequently, in stage III, two milled ceramic superstructures combined with a titanium milled bar were delivered as a final screw-retained restoration with the application of scan flags (horizontal scan bodies) for intraoral scanning. Results: The aforementioned technologies can all be implemented and merged into one complex treatment plan combining high predictability, successful esthetics, and a reliable and accurate end result. Even though the concept of scan flags is relatively new, this case shows its potential and merit. Conclusions: This case represents the power of the digital approach as a helpful tool in the recreation of functional and esthetic smiles in compromised conditions in periodontal patients. Full article

Background and Clinical Significance: Denture stomatitis is a clinical manifestation of oral candidiasis, often seen in individuals wearing removable dentures that lead to the formation of sub-prosthetic stomatitis. This is particularly common in maladjusted appliances that have been in use for many years. Studies have shown that patients with systemic diseases such as diabetes, or other medical complexities, have a higher likelihood of developing denture stomatitis. To address this problem, the use of implant-retained dentures with different types of attachments has been introduced, providing increased comfort and hygiene for edentulous patients. However, this solution is not without its own set of challenges, being that the prolonged contact with mucosal surfaces can lead to challenges in cleaning and managing plaque depending on the attachment. Case Presentation: In this clinical case report, we present a female patient who developed bar-retained prosthetic stomatitis induced by oral candidiasis a few months after receiving her provisional prosthesis. Conclusions: In conclusion, this case report emphasizes the need to consider both systemic and local factors when preventing and treating denture stomatitis. By understanding the risk factors involved, healthcare professionals can provide their patients with the best possible care, helping to reduce the prevalence of oral candidiasis in individuals who use implant-retained dentures. Full article

This clinical report details the prosthetic rehabilitation of a patient following maxillary ablation to remove a peripheral giant cell granuloma. After a hemimaxillectomy, the defect was reconstructed with a fasciocutaneous radial free flap. Implant placement was digitally planned using the dual scanning technique, and implants were inserted with the aid of an acrylic surgical guide. After implant osseointegration, a removable implant-supported overdenture with an electroplated secondary structure retained on a titanium bar was fabricated. At the 3-year follow-up, peri-implant tissues remained healthy, showing only mild gingival hyperplasia around the bar, while no prosthesis retention loss or significant technical complications were observed. In conclusion, the reconstruction of the moderate maxillary defect using a soft-tissue flap provided satisfactory functional and esthetic outcomes, significantly enhancing patient satisfaction. However, the limited bone availability necessitated precise implant planning to ensure adequate biomechanical support for the overdenture. Full article

Background/Objectives: Implant treatment in patients who require teeth extraction due to periodontitis presents a significant challenge. The consideration of peri-implantitis is crucial when planning the placement of dental implants. The predictability of implant treatment relies on the suitability of both hard and soft tissue quality. The aim of this article is to present a case report demonstrating a secure treatment protocol for implant procedures in patients with periodontitis requiring the extraction of all teeth, soft tissue management targeted at increasing the keratinized mucosa zone, and the provision of a reliable prosthetic solution. The secondary objective is to review the relevant literature regarding the significance of keratinized mucosa surrounding dental implants and its association with the occurrence of peri-implantitis. Case presentation: A 65-year-old female with generalized periodontitis, stage IV grade C and very poor oral hygiene came for treatment and rehabilitation of the lower jaw. CBCT revealed periodontal lesions and labio-lingual ridge dimensions in the region of teeth 34–44 from 8.0 to 10.2 mm. The first surgery included teeth extraction and periodontal lesions enucleation with simultaneous placement of four implants in the positions of teeth 32, 34, 42, 44. The second-stage surgery involved increasing the keratinized mucosa using two free gingival grafts. Conclusions: The present case report described the treatment process of the patient with periodontitis, including immediate implantation in the infected region, soft tissue augmentation using free gingival grafts and the ultimate placement of a bar-retained overdenture for final restoration. After two years of observation, despite questionable hygiene, no symptoms of gingival inflammation were detected. Furthermore, there is limited information in the literature regarding the correlation between inadequate keratinized gingiva and the occurrence of peri-implantitis. Full article

This article presents the outcomes of prosthetic oral rehabilitation using CAD/CAM telescopic bar overdentures in patients with oral cancer (n = 3), severe facial trauma (n = 2), or various syndromes (n = 1), all suffering from severe tissue deficits and requiring complex and comprehensive oral rehabilitation. The aim was to assess the durability and functionality of implant-retained prosthetic structures, ensuring easy oral hygiene and minimizing specialized follow-up needs. The data for this study were sourced from a retrospective cohort at Helsinki University Hospital. The prosthetic reconstruction encompassed the Atlantis 2in1 and the Createch removable telescopic systems. Thus, 40 implants were placed (4 to 7 per patient), with prosthetic structures in the maxilla (n = 4 patients), in the mandible (n = 1), and in both jaws (n = 1). Two patients experienced no complications, two patients had part of the acrylic resin break, and one patient experienced loosening of the bar structure. All complications associated with prosthetic structures were successfully managed, and none of the implants were lost. The follow-up time ranged from 7 to 126 months. This rehabilitation is proved to be an effective solution for patients with complex oral conditions, facilitating both functional restoration and ease of maintenance. These findings underscore the importance of individualized treatment approaches in cases of tissue deficits. Full article

Background: Complex implant reconstructions in patients with residual dentition due to periodontitis is a challenging task in many aspects. Methods: This study shows a full digital workflow combining 3D printing, guided implant placement, intraoral scanning and welding with immediate loading and digital smile design. An analog impression was taken to validate the passive fit of final restorations. The whole treatment plan was divided into three stages. The first stage included an intraoral scan of baseline dentition, and then the extraction of all teeth was performed, implanting four temporary implants and providing the patient with removable temporary prosthesis. The second stage was to scan the removable temporaries, implanting 10 implants and multi-unit abutments (MUA), and create a rigid construction via the intraoral welding of titanium bar and by fixing it to the 3D-printed temporary reconstructions (designed with DSD) as a form of immediate loading. The third stage included the scanning of screw-retained temporary reconstructions, then scanning from the MUA level and creating final reconstruction. Results: The presented workflow enabled the delivery of some sort of restoration to the patient at every moment of the treatment and to sustain the required esthetic effect with decent comfort of use even in the early stages. Conclusions: A full digital workflow is a reliable treatment method even in complex cases. Full article

The objective of this study was to compare the distribution of stress in the maxillary bone, dental implants, and prosthetic components supporting implant-supported maxillary overdentures with partial palatal coverage, in both splinted and unsplinted designs. Two models of maxillary overdentures were designed using the Exocad Dental CAD program, which included cancellous and cortical bone. The complete denture design and abutments (locator abutments in the unsplinted and Hader bar with Vertix attachments placed distally in the splinted variant) were also designed. The denture material was PEEK (Polyetheretherketone), and the method used to analyze patient-specific 3D X-ray scans was 3D QCT/FEA (three-dimensional quantitative computed tomography-based finite element analysis). Loading was divided into three load cases, in the frontal region (both incisors of the denture) and distal region (both molars and first premolar of the denture). The forces applied were 150 N with an oblique component with a buccal inclination of 35° in the frontal region, and 600 N with a buccal inclination of 5° (molars) or solely vertical (premolar) in the distal region. The model with locator abutments showed higher stresses in all load cases in both analyzed implant variants and in the maxilla. The differences in stress distribution between the splinted and unsplinted variants were more significant in the distal region. According to the results of the present study, the amount of stress in bone tissue and dental implant parts was smaller in the splinted, bar-retained variant. The findings of this study can be useful in selecting the appropriate prosthetic design for implant-supported maxillary overdentures with partial palatal coverage. Full article

Obtaining accurate models and well-fitting prostheses during the fabrication of complete implant-supported prostheses has been a significant challenge. Conventional impression methods involve multiple clinical and laboratory steps that can lead to distortions, potentially resulting in inaccurate prostheses. In contrast, digital impressions may eliminate some of these steps, leading to better-fitting prostheses. Therefore, it is important to compare conventional and digital impressions for producing implant-supported prostheses. This study aimed to compare the quality of digital intraoral and conventional impressions by measuring the vertical misfit of implant-supported complete bars obtained using both types of techniques. Five digital impressions using an intraoral scanner and five impressions using elastomer were made in a four-implant master model. The plaster models produced with conventional impressions were scanned in a laboratory scanner to obtain virtual models. Screw-retained bars (n = five) were designed on the models and milled in zirconia. The bars fabricated using digital (DI) and conventional (CI) impressions were screwed to the master model, initially with one screw (DI1 and CI1) and later with four screws (DI4 and CI4), and were analyzed under a SEM to measure the misfit. ANOVA was used to compare the results (p < 0.05). There were no statistically significant differences in the misfit between the bars fabricated using digital and conventional impressions when screwed with one (DI1 = 94.45 µm vs. CI1 = 101.90 µm: F = 0.096; p = 0.761) or four screws (DI4 = 59.43 µm vs. CI4 = 75.62 µm: F = 2.655; p = 0.139). Further, there were no differences when the bars were compared within the same group screwed with one or four screws (DI1 = 94.45 µm vs. DI4 = 59.43 µm: F = 2.926; p = 0.123; CI1 = 101.90 µm vs. CI4 = 75.62 µm: F = 0.013; p = 0.907). It was concluded that both impression techniques produced bars with a satisfactory fit, regardless of whether they were screwed with one or four screws. Full article

Numerous attachment systems exist for implant-supported overdentures, with each having specific limitations in terms of retention, cost, wear, maintenance and cleanability. A retrospective analysis of patients restored with implant-supported overdentures using bars, telescopic crowns and Locator-type attachments was performed and the patients were interviewed. An in vitro strain gauge study compared telescopic crowns, Locator-type attachments and a novel flexible attachment system employing a shape memory alloy (NiTi) with respect to peri-implant strain development during insertion, loading and removal of an overdenture. A significantly lower number of attachment-related complications was observed in bars as compared to telescopic crowns (p = 0.00007) and Locator-type attachments (p = 0.00000), respectively. Greater overall patient satisfaction was noted in bar-retained restorations while Locator-type attachments led to lower levels of satisfaction regarding prosthesis retention. In vitro, telescopic crowns caused maximum strain development during prosthesis insertion and loading, while during removal this was observed in Locators with white retentive inserts. NiTi attachments caused significantly lower strain development during insertion as compared to telescopic crowns (p = 0.027). During loading, NiTi attachments caused significantly lower strain development than Locators with blue retentive inserts (p = 0.039). During removal, NiTi attachments caused significantly less strain development as compared to Locators with white retentive inserts (p = 0.027). Positional discrepancies between male and female attachment parts affected the retention and reaction force between both components, which may be minimized by using the novel NiTi attachment system. This may be beneficial in terms of component wear and implant loading. Full article

The atrophic edentulous maxilla is demanding for dental implant placement because of extensive resorption of the alveolar ridge after teeth loss and, consequently, the proximity of the anatomical structures, nasal cavity, and maxillary sinus. Treatment options are short implants, guided bone regeneration, onlay grafts, Le Fort I osteotomy with interpositional bone grafting, distraction osteogenesis, or nasal floor elevation. Nasal floor elevation is a method of augmentation of premaxilla by raising the base of the nose. The aim of this case report is to evaluate the success of implants placed after nasal floor elevation. A 75-year-old female patient came to the Clinical Department of Oral Surgery, University Hospital Centre Zagreb, unsatisfied with her complete removable denture. Clinical and radiological examination revealed severe maxillary alveolar ridge atrophy. Nasal floor elevation was made under local anesthesia through aperture piriformis and lateral window in the distal part. After eight months, four implants were placed and, after period of osseointegration, a bar-retained implant overdenture was made. This case report shows that nasal floor augmentation can be considered among the surgical techniques to allow implant-supported rehabilitation of the atrophic anterior maxilla. Full article

The purpose of this study was to evaluate the effects of various fabrication techniques and materials used in implant-supported mandibular overdentures with a Hader bar attachment over added stress distribution. Three-dimensional geometric solid models, consisting of two implants (3.3 mm × 12 mm) placed at the bone level on both mandibular canine regions and a Hader bar structure, were prepared. Model 1 simulated a bar retentive system made from Titanium Grade 5 material by Computer Numerical Control (CNC) milling technique without using any converting adapter/multi-unit element on the implants, while Model 2 simulated the same configuration, but with converting adapters on the implants. Model 3 simulated a bar retentive system made from Cobalt-Chromium material, made by using conventional casting technique with converting adapters on the implants. Static loads of 100 Newton were applied on test models from horizontal, vertical and oblique directions. ANSYS R15.0 Workbench Software was used to compare Von Mises stress distribution and minimum/maximum principal stress values, and the results were evaluated by using Finite Element Analysis method. As a result, the highest stress distribution values under static loading in three different directions were obtained in Model 1. Stress was observed intensely around the necks of the implants and the surrounding cortical bone areas in all models. In scope of the results obtained, using converting adapters on implants has been considered to decrease transmission of forces onto implants and surrounding bone structures, thus providing a better stress distribution. It has also been observed that the type of material used for bar fabrication has no significant influence on stress values in those models where converting adapters were used. Full article

There have been considerable recent technological developments for implant overdenture attachments. This study presents an overview of the biomechanical and biomolecular aspects of various attachments for implant overdenture. Available articles on attachments for implant overdenture were reviewed from January 1980 to August 2021 in the ScienceDirect, MEDLINE/PubMed, and Web of Science resources, and relevant studies were included in this study. We focused on the following topics: attachment systems, retention of various attachments, stress distribution with different attachments, the design and fabrication of attachments, digital techniques in overdenture attachments, and the effects of attachments in peri-implant health. We found that plastic resin is commonly used for ball and bar attachments, whereas nylon resin is commonly used in locator attachments. The locator system offers a valuable attachment option for implant-retained overdenture. Attachment retention reduces while lateral force increases with implant inclination in overdenture. The higher the retention of an overdenture attachment, the higher the transferred stresses. Additionally, clip loading produces more stress in implants and precision elements than bar-retained dentures. As such, we conclude that the ball and locator systems the best overdenture systems due to their superior tissue response, survival rate, and patient satisfaction. Full article

This paper aims to compare, in vitro, the biomechanical properties of an overdenture retained by two bar-retained implants and an overdenture retained by two bar-retained implants with ball attachments. An edentulous mandible model was prepared for the study based on the FRASACO mold with two implants. In the first system, the “rider” type (PRECI-HORIX, CEKA) retention structure and the complete mandibular denture with the matrix were made. In the second system, the “rider” type retention suprastructure was also used. In the distal part, (CEKA) clips were placed symmetrically, and a complete mandibular denture, together with the matrix on the bar, and the clip patrices were made. A numerical model was developed for each system where all elements were positioned and related to geometric relations, as in reality. The FEA analysis (finite element analysis) was carried out for seven types of loads: with vertical forces of 20, 50, and 100 N and oblique forces of 20 and 50 N acting on individual teeth of the denture, namely central incisor, canine, and first molar. Displacements, stresses, and deformations within the systems were investigated. Maximum denture displacement in the first system was 0.7 mm. Maximum bar stress amounted to 27.528 MPa, and implant stress to 23.16 MPa. Maximum denture displacement in the second system was 0.6 mm. Maximum bar stress amounted to 578.6 MPa, that of clips was 136.99 MPa, and that of implants was 51.418 MPa. Clips cause smaller displacement of the overdenture when it is loaded but generate higher stress within the precision elements and implants compared to a denture retained only by a bar. Regardless of the shape of the precision element, small deformations occur that mainly affect the mucosa and the matrix. Full article

In this paper, we assess the pressure between the overdenture located in the mandible and supported by a bar retained on two implants and the prosthodontic area. For testing, a model of an edentulous mandible was created using a mold by FRASACO with two implants and a “rider” bar inserted. A complete mandibular denture with polypropylene matrices was made. Three types of matrices of various stiffness were applied. The mandible and overdenture geometry was mapped using a digital image obtained with a Steinbichler Comet L3D 3D scanner. Finite element method calculations were performed in the Abaqus FEA software. The results demonstrate that the maximum contact pressure is observed when the loads are associated with canines. A critical case for the lower posterior is chewing performed by the molars. The pressure zone is the largest for POM-1 with Young’s modulus of 1.5 GPa and is reduced by 5.0% and 7.8% for POM-2 (E = 2.5 GPa) and POM-3 (E = 3.5 GPa), respectively. The stress distribution under the prosthesis mostly depends on the region loaded onto it. The applied load produces a slight contact pressure between the denture and the prosthodontic area in the anterior zone. A change in polypropylene matrix stiffness does not affect contact pressures. Full article