Search Results (59)

Background: Mucostatic impressions have been always indicated in thin, sharp, or flabby ridges, and have been addressed for their beneficial effect on long-term residual ridge stability. Nonetheless, a purely mucostatic impression was not possible until intraoral scans became available. This provides an option for digital removable denture which is biologically sensible but might reduce retention in comparison with a mucocompressive impression with border molding. On the other hand, pressure applied to the mucosa may have harmful effects on the long-term residual ridge stability, causing higher resorption and ultimately reduced denture retention. Hence, the possibility to merge mucostatics and mucocompressive philosophies would be a clinically and biologically sensible option for oral rehabilitation in aging populations where patients will potentially wear dentures for longer periods. This possibility is demonstrated in this technical report with a cast-free digital workflow. Technique: Baseplates for occlusion rims, closely adapted to the mucosa, were designed on intraoral scans of edentulous arches and, once 3D-printed, used to register maxillomandibular relations and information for tooth arrangement, as well as to perform border molding. Occlusion rims were then scanned and, within the 3Shape Dental System 2024 software program, the intaglio surfaces of their baseplates were segmented and inverted to obtain the digital master casts which incorporated the precise reproduction of the molded borders. Then, denture design was performed and manufactured; no limitations regarding manufacturing options are applicable to the presented technique. Conclusions: The potential benefits (i.e., improved retention in the initial period after denture delivery and the preservation of tissues) of the presented digital cast-free workflow, based on merging mucostatic and mucocompressive philosophies to obtain dentures with a mucostatic intaglio surface and functional borders, are sensible clinical outcomes which recommend the clinical application of the technique, although further validation, especially in the long term, is required. Full article

Introduction: Mandibular complete dentures often pose challenges due to anatomical and functional limitations. Impression techniques, including functional, mucostatic, compressive, selective pressure, and neutral zone methods, play a crucial role in achieving stability and retention. In 1999, Abe introduced the Suction Effective Mandibular Complete Denture (SEMCD) technique, revolutionizing mandibular denture retention by incorporating functional extensions and achieving a peripheral seal even in the presence of mobile soft tissues. Case report: An 87-year-old male presented to a private dental clinic with the chief complaint that his current lower complete denture lacked retention and stability. Intraoral examination revealed a severely resorbed mandibular edentulous ridge with movable retromolar pads and a prominent spongy lingual area. This case report describes the integration of Abe’s concepts into a digital workflow, using a single-step intraoral scanning technique and digital design software to fabricate a mandibular denture with enhanced retention and stability. Conclusions: This approach minimizes the number of clinical steps involved, improves patient comfort, and achieves predictable outcomes, highlighting the utility of digital technologies in modern prosthodontics. Full article

Conventional complete dentures remain to be an important treatment for edentulous patients, especially those of low socioeconomic status. This study is a retrospective analysis that aims to elucidate influencing factors of post-insertion complications and patient satisfaction. Clinical records of 164 patients who received both maxillary and mandibular complete dentures at an Australian university teaching clinic were assessed and analysed. The parameters considered include reason for attendance, presenting clinical status, experience of operator, numbers of appointments for fabrication and adjustment, post-insertion complications and events, and patient satisfaction. The differences among selected attributes were analysed using a Mann–Whitney test, Chi-square test, or Kruskal–Wallis test where applicable, while the relationships between discrete variables were assessed by Kendall’s correlation. First, the number of appointments for fabrication differed significantly between female (6.8 ± 1.8) and male patients (6.2 ± 1.3; p = 0.025) and between student (6.7 ± 1.7) and professional operators (6.0 ± 1.1; p = 0.015). The number of appointments for adjustment was significantly associated with patient age (τ_b = 0.167, p = 0.003) and sharply declined after the first three months. Second, post-insertion pain was the most frequent complication, and it was significantly more associated with the mandible than the maxilla (χ² = 21.670, p = 0.000). Similarly, mandibular complete dentures were also significantly more associated with post-insertion reline than the maxillary (χ² = 8.804, p = 0.003). Lastly, patient satisfaction was significantly associated with patient attendance with old/worn dentures (χ² = 9.468, p = 0.002), as well as the absence of retention/stability issues (χ² = 41.712, p = 0.000), post-insertion reline (χ² = 29.300, p = 0.000), or denture replacement (χ² = 13.968, p = 0.000). Dissatisfied patients had a significantly higher age (70.9 ± 11.0 vs. 66.2 ± 12.6; p = 0.023) and number of appointments for adjustment (4.9 ± 3.5 vs. 3.1 ± 2.1; p = 0.001) than satisfied patients. In summary, these findings revealed the above factors that influence the fabrication process, post-insertion complication, and patient satisfaction of conventional complete dentures. Future research may include analysis of cases completed at private practices and consideration of other potentially relevant factors such as denture usage and mental status. Full article

A common challenge encountered with both traditional and digitally produced dentures involves the extraction of artificial teeth from the denture base. This narrative review seeks to present an updated perspective on the adherence of synthetic teeth for denture base materials, employing diverse methods. Dental technicians often employ chemical approaches and mechanical techniques (including abrasion, laser treatment, and abrasive blasting) to augment the retention of denture teeth. However, the efficacy of these treatments remains uncertain. In certain instances, specific combinations of Denture Base Resin (DBR) materials and artificial teeth exhibit improved performance in conventional heat-cured dentures following these treatments. The primary reasons for failure are attributed to material incompatibility and inadequate copolymerization. As new denture fabrication techniques and materials continue to emerge, further research is imperative to identify optimal tooth-DBR combinations. Notably, 3D-printed tooth–DBR combinations have demonstrated reduced bond strength and less favorable failure patterns, while utilizing milled and traditional combinations appears to be a more prudent choice until advancements in additive manufacturing enhance the reliability of 3D-printing methods. Full article

Background and Objectives: Despite the identified benefits of early implant loading, studies have questioned its advantages compared to delayed loading in edentulous patients. This study aimed to evaluate clinical peri-implant parameters and marginal bone loss around early placed and loaded mandibular implant overdentures with a 60-month follow-up. Materials and Methods: In this prospective cohort study, 43 patients were enrolled to receive 86 early loading sub-crestal dental implants through prosthetic guides. Implant overdentures were supported by two isolated implant locator attachments between two mental foramens. Clinical peri-implant parameters, including plaque index (PI), bleeding index (BI), peri-implant pocket depth (PIPD), and marginal bone loss (MBL) were evaluated using standardized techniques at 1, 12, 24, 36, 48, and 60 months follow-up. At 60 months, complications associated with implant overdentures (IOD’s) were noted. The mean comparison of peri-implant clinical parameters was performed through ANOVA test. A p-value of ≤0.05 was taken as significant. Results: Out of the total 43 enrolled patients, 8 patients were lost during follow-up; as a result, 35 patients completed the 5 years follow-up. The mean values of PI, BI, and PIPD increased with no statistical difference (p > 0.05). For marginal bone loss, an increase in the mean values was noted at different time intervals with statistical differences (p < 0.001). The most common complications noted were loosening of the abutment, occlusal adjustment, retentive locator loosening and replacement, and relining of the denture. Conclusions: Early placement of IODs failed to prevent bone loss over time and was associated with complications, predominantly consisting of abutment loosening, occlusal adjustments, broken retentive locator components, relining, and rebasing. Full article

Clinical indications for the newly released Ti-Zr (Roxolid^®) alloy mini-implants (MDIs) aimed for overdenture (OD) retention in subjects with narrow alveolar ridges are not fully defined. The aim of this study was to analyze peri-implant and posterior edentulous area microstrains utilizing models of the mandible mimicking a “real” mouth situation with two (splinted with a bar or as single units) or four unsplinted Ti-Zr MDIs. The models were virtually designed from a cone beam computed tomography (CBCT) scan of a convenient patient and printed. The artificial mucosa was two millimeters thick. After MDI insertion, the strain gauges were bonded on the oral and vestibular peri-implant sites, and on distal edentulous areas under a denture. After attaching the ODs to MDIs, the ODs were loaded using a metal plate positioned on the first artificial molars (posterior loadings) bilaterally and unilaterally with 50, 100, and 150 N forces, respectively. During anterior loadings, the plate was positioned on the denture’s incisors and loaded with 50 and 100 N forces. Each loading was repeated 15 times. The means with standard deviations, and the significance of the differences (two- and three-factor MANOVA) were calculated. Variations in the MDI number, location, and splinting status elicited different microstrains. Higher loading forces elicited higher microstrains. Unilateral loadings elicited higher microstrains than bilateral and anterior loadings, especially on the loading side. Peri-implant microstrains were lower in the four-MDI single-unit model than in both two-MDI models (unsplinted and splinted). Posterior implants showed higher peri-implant microstrains than anterior in the four-MDI model. The splinting of the two-MDI did not have a significant effect on peri-implant microstrains but elicited lower microstrains in the posterior edentulous area. The strains did not exceed the bone reparatory mechanisms, although precaution and additional study should be addressed when two Ti-Zr MDIs support mandibular ODs. Full article

The removable partial denture, despite new technologies and new materials, continues to play a significant role in clinical dental practice. The purpose of the following study was to evaluate the design of new retention devices in Kennedy class II scenarios. For the study of “lamellar” retentive devices, four prosthetists were chosen. According to inclusion and exclusion criteria, prosthetists selected 16 patients (8 women and 8 men) whose upper arches had to be rehabilitated using a removable partial prosthesis. The results showed that the parameters taken into consideration, such as satisfaction, stability, aesthetics, and retention, had an average score that was higher than 3.30 (range 1–4), with an average standard deviation of 0.6225 in the four parameters, indicative that the data were relatively homogeneous and coherent. In conclusion, we can state that the skeletonized prosthesis with lamellar retentions, designed for Kennedy class II scenarios, has shown high acceptance in selected patients. Full article

Today, dental implantology represents a reliable technique for treating both partial and total edentulism. The fixation of dentures on dental implants can be achieved using various techniques, where the choice of a specific technique depends on the patient’s individual needs, the jawbone’s condition, and the prosthesis design. Currently, the two most common types of prosthetic abutment connections are cemented and screwed, each with its own set of advantages and disadvantages. This study aimed to analyze a novel Morse cone connection system between the prosthesis and implant using finite element analysis (FEA). The analysis of connection retention was conducted using three different approaches: analytical, in vitro, and FEA. Three-dimensional models were created for systems comprising an abutment, healing cap, and crown under three inclination conditions: 0°, 15°, and 30°. Using Ansys finite element software (R1 2023), the impact of the tilt on the system retention was examined. The FEA showed results comparable with the in vitro studies regarding the retention strength for an abutment cap system with a 4° taper, obtaining 66.6 N compared with the 68 N calculated in our in vitro study. The inclination of the abutment affected the system retention due to the hole made in the abutment’s surface, decreasing the contact area between components. The Morse cone prosthesis–implant connection system was found to be the most stable and efficient compared with threaded or cemented systems. The retention was influenced by factors such as the abutment conicity, insertion strength, and the contact surface between components. Full article

This review describes the role of modern preprosthetic surgery. The atrophic edentulous jaw can cause severe functional impairment for patients, leading to inadequate denture retention, reduced quality of life, and significant health problems. The aim of preprosthetic surgery is to restore function and form due to tooth loss arising from congenital deformity, trauma, or ablative surgery. Alveolar bone loss is due to disuse atrophy following tooth loss. The advent of dental implants and their ability to preserve bone heralded the modern version of preprosthetic surgery. Their ability to mimic natural teeth has overcome the age-old problem of edentulism and consequent jaw atrophy. Controversies with preprosthetic surgery are discussed: soft tissue versus hard tissue augmentation in the aesthetic zone, bone regeneration versus prosthetic tissue replacement in the anterior maxilla, sinus floor augmentation versus short implants in the posterior maxilla—interpositional bone grafting versus onlay grafts for vertical bone augmentation. Best results for rehabilitation are achieved by the team approach of surgeons, maxillofacial prosthodontists/general dentists, and importantly, informing patients about the available preprosthetic surgical options. Full article

The aging population in developed countries has increased the number of edentulous patients and, therefore, the need for prosthetic rehabilitation to improve their quality of life. Complete dentures are the main treatment option in these cases. The use of CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) in dentistry has improved clinical protocols and outcomes, achieving a reduction in work time and economic costs for the patients. The main objective of this review was to compare the characteristics of conventional and digital dentures, attempting to determine whether the use of new technologies represents an improvement in the properties of removable complete dentures. A bibliographic review was carried out in the PubMed/MEDLINE, Cochrane Library, Scielo, and Embase databases. With the initial search, 157 articles were obtained. After applying the inclusion and exclusion criteria, 64 publications were selected for this bibliographic review. The different conclusions of the studies consulted were compared regarding fit and retention, fracture resistance, surface roughness, biocompatibility, and aesthetics, taking into account the different methods of prostheses fabrication. In general, digital prostheses have shown better mechanical properties and, consequently, better biocompatibility and aesthetics than conventional prostheses. However, the obtained results were very heterogeneous, preventing a supported conclusion. Full article

Patients with Kennedy Class I are usually treated with clasp-retained removable partial dentures (RPDs) as the prosthetic gold standard. For additional stabilization of the RPD, clinicians are often confronted with the question of secondary implant placement, which requires the fabrication of new prostheses. This case report is part of an ongoing multi-center randomized controlled study (RCT) investigating conventional RPDs without and with supplementary implants. A design of the RPD framework, including matrix housings, is crucial to enable subsequent implant retention or support. Ultra-short implants (Straumann TL 4.1 × 4 mm) offer the opportunity for additional support and retention in the edentulous posterior region, where bone availability is often reduced. This future-oriented and minimally invasive approach with virtual treatment planning and guided implant surgery offers the possibility of simplified functional and cost-effective aftercare. Full article

Purpose: To evaluate fit and retention of cobalt–chromium removable partial denture (RPD) frameworks fabricated with selective laser melting (SLM). Methods: Three types of framework for clasp-retained RPDs were virtually designed and fabricated using SLM (n = 30). For comparison, 30 additional frameworks were produced using conventional lost-wax casting. A biomechanical model was created, incorporating extracted teeth mounted on flexible metal posts. Using this model, horizontal constraint forces resulting from a misfit were measured using strain gauges, while vertical forces were not recorded. The constraint force components and resultant forces were determined for all abutment teeth, and the maximum retention force during RPD removal from the model was also assessed. For statistical evaluation, the two fabrication methods were analyzed by calculating the means and standard deviations. Results: The average horizontal constraint forces showed similar values for both fabrication methods (SLM: 3.5 ± 1.0 N, casting: 3.4 ± 1.6 N). The overall scatter of data for cast RPDs was greater compared to those fabricated using SLM, indicating a better reproducibility of the SLM process. With regard to retention, the intended retention force of 5–10 N per abutment tooth was not attained in one of the cast groups, while it was consistently achieved in all SLM groups. Conclusions: This in vitro study found that SLM is a promising option for the manufacture of cobalt–chromium RPD frameworks in terms of fit and retention. Full article

The purpose of this study was to evaluate the retentive forces over time of removable partial denture clasps fabricated by the digital method. Occlusal rest seats were fabricated on three premolar teeth fixed in acrylic blocks (9 × 20 × 40 mm). Digitization of the teeth was performed using a laboratory scanner (Zirkonzahn Scanner S600 GmbH, Gais, Italy). After the analysis and determination of the insertion axis, two types of clasps with mesial occlusal rests were designed per tooth: the back-action and the reverse back-action clasps, using the Partial Planner Zirkonzahn program. The file was sent for fabrication of six metal clasps from a cobalt-chromium SP2 alloy in the EOSINT M270 system by a direct laser sintering process. The Instron 5544 universal testing machine was used to perform 20,000 cycles of clasp insertion and removal in the corresponding tooth with a load cell of 100 N and a speed of 2.5 mm/s. The retentive force was recorded for each of the 1000 cycles, and the change in retention over time was calculated. Statistical analysis was performed using the nonparametric Mann–Whitney test and a significance level of 5%. At 16,000 cycles, a maximum change in retention of 3.74 N was recorded for the back-action clasps and a minimum of −24.28 N at 1000 cycles for the reverse back-action clasps. The reverse back-action clasps exhibited statistically significant lower change in retention than the reverse-action clasps at 4000 and 5000 cycles. No differences were observed in the remaining cycles. During the 20,000 cycles, the change in retention was low regardless of the type of clasp. For most cycles, there were no differences in the change in retention between the two types of clasps. Full article

Xerostomia and hyposalivation are highly prevalent conditions in old age, particularly among multimorbid elders, and are often attributed to the use of multiple medications. These conditions negatively affect oral functions, such as chewing, swallowing, speech, and taste. Additionally, the lack of lubrication of the oral mucosa frequently leads to super-infections with candida. Denture retention and comfort may also be compromised. The risk of dental caries and erosion of natural teeth increases since saliva, which is essential for repairing initial lesions in tooth structures, is insufficient. The dry sensation in the mouth also impacts the emotional and social well-being of elderly individuals. Patients experiencing xerostomia often avoid certain foods that are uncomfortable or difficult to consume. However, some foods may alleviate the symptoms or even stimulate salivation. This review discusses the limited available evidence on nutritional advice for patients with xerostomia and aims to provide insight into the patient’s perspective while offering clinical recommendations. Future studies should focus on investigating the nutritional intake of individuals suffering from xerostomia or hyposalivation in order to ensure oral health comfort, prevent malnutrition, and minimize the impact on their quality of life. Full article

Dental-implant-supported reconstructions provide comfort and improvements in prosthetic function, adaptation, and stability over conventional treatment options. The objective of this study was to evaluate the effect of different denture cleansing solutions and their influence on the deterioration and loss of retention of overdenture attachments in a 12-month clinical-use simulation. In this way, ten specimens each of different brands of retentive caps made of Teflon (OT Equator^® (Rhein83, Bologna, Italy), Locator^® (Zest Anchors, Escondido, CA, USA), Kerator^® (KJ Meditech, Gwangiu, Republic of Korea), and Locator R-Tx^® (Zest Anchors, Escondido, CA, USA)) were immersed in five different cleaning solutions (Kukident^® (P&G Tech, Oxford Parkway, UK), Benfix^® (Laboratorios URGO S.L., Guipúzcoa, Spain), Corega^® (Stafford Miller, Waterford, Ireland), and Protefix^® (Neuhofer Weiche, Parchim, Germany)), and tap water was used as the control group, in a simulation that lasted 12 months. Data were analyzed using two-way ANOVA and a Tukey HSD. Furthermore, a Levene Test and Shapiro–Wilk tests were performed to assess the validation of the ANOVA assumptions. The statistical analysis was performed using R version 4.2.2 software with the significance level set to p < 0.05. There were significant statistical differences between the different manufacturers regarding the retention forces of the attachment’s retentive caps (F = 322.066, p < 0.001). For the cleaning solution groups, different statistical results between Kukident^® (P&G Tech, Oxford Parkway, UK) (p < 0.05) and Benfix^® (Laboratorios URGO S.L., Guipúzcoa, Spain) (p < 0.05) were observed. There were no significant statistical differences between Corega^® (Stafford Miller, Ireland), Protefix^® (Neuhofer Weiche, Parchim, Germany), and tap water, even though the retention forces decreased in all of them. Full article