Search Results (556)

The increasing adoption of digital workflows in implant dentistry relies heavily on the accuracy of implant scan bodies (ISBs), which may be affected by repeated sterilization. This in vitro study evaluated the effect of 50 steam sterilization cycles on the dimensional stability of polymer and titanium ISBs. A total of 100 test specimens (n = 50 per material) were scanned before (T0) and after sterilization (T50) using a high-resolution intraoral scanner, generating 900 STL datasets for metrological analysis. Surface deviation, linear displacement, and angular deviation were assessed using validated industrial and dental software, with statistical evaluation performed through paired tests and linear mixed-effects models. Both materials exhibited statistically significant dimensional changes after sterilization (p < 0.001). Titanium scan bodies demonstrated greater linear deformation (69.76 μm) compared to polymer ones (49.50 μm), while maintaining superior angular stability (0.21° vs. −1.69° mean angular change in the polymer group). A significant interaction between material type and sterilization was observed. Despite high baseline precision, repeated autoclaving induced clinically relevant deviations in both materials. These findings indicate that cumulative sterilization cycles adversely affect ISB accuracy and highlight the importance of adhering to manufacturer recommendations to ensure optimal prosthetic outcomes. Full article

Background/Objectives: Immediate provisionalization in the esthetic zone is a well-documented but technique-sensitive procedure, and the choice of provisional connection geometry, with or without an antirotational index, remains debated. The aim of this retrospective single-arm cohort clinical study was to evaluate the clinical performance of a digitally planned, guide-delivered provisionalization protocol using prefabricated provisional crowns connected to 5-degree Morse taper implants without an antirotational index, with emphasis on emergence profile shaping and peri-implant tissue stability at one year; Methods: Twenty consecutive single-implant cases treated according to the standardized protocol from January 2024 onward and completing at least one year of follow-up after definitive crown delivery by the February 2026 data-lock date were included (19 female, 1 male; mean age 38.1 ± 12.7 years; 18 anterior and 2 premolar sites). All implants were placed with primary insertion torque ≥ 30 N·cm (mean 34.75 ± 2.55 N·cm) and immediately restored with a digitally designed, non-antirotational provisional crown. Primary outcome was provisional retention without major intervention; secondary outcomes included biologic complications, papilla score, marginal bone change at T0–T3 and T3–T4, and buccal contour change (T0 vs. T2 intraoral scan superimposition). Wilson 95% confidence intervals, Fisher’s exact test, and Mann–Whitney U test were used (α = 0.05); Results: Provisional retention without major intervention was 75.0% (15/20; 95% CI 53.1–88.8). Biologic complications were uncommon (bleeding on probing, suppuration, midfacial recession, and chairside adjustment, each 5.0%). Mean total marginal bone loss at one year was 0.37 ± 0.20 mm; mean buccal contour gain was 1.41 ± 0.48 mm. A complete papilla was preserved in 70.0% of cases. Conclusions: Digitally planned, guide-delivered provisionalization on a non-antirotational 5-degree Morse taper interface appears clinically feasible for emergence profile shaping in the esthetic zone, with favorable peri-implant tissue outcomes at one year. Full article

Background/Objectives: The development of high-performance biocompatible polymers such as zirconium-reinforced polyether ether ketone (BioHPP^®) has expanded the range of materials available for implant-supported prostheses, traditionally limited to metal alloys and zirconia. Due to its favorable mechanical properties and elastic modulus similar to cortical bone, BioHPP^® has been proposed as a potential alternative in implant prosthodontics. This systematic review aimed to analyze the biomechanical behavior of zirconium-reinforced PEEK and assess its advantages and limitations in implant prosthetic applications. Methods: A systematic review was conducted in accordance with PRISMA 2020 guidelines, including studies published between 2011 and 2025 that evaluated the performance of BioHPP in implant prosthetic applications. Results: The search strategy identified 34 studies that met the inclusion criteria. The included studies evaluated mechanical properties such as fracture resistance, elastic modulus, stress distribution, and peri-implant tissue response. Zirconium-reinforced PEEK demonstrated fracture resistance values reaching up to 1623.31 N and an elastic modulus of approximately 4 GPa, comparable to cortical bone. Several studies also reported favorable stress distribution patterns and reduced mechanical complications when compared with conventional metallic materials. Conclusions: Zirconium-reinforced PEEK exhibits promising biomechanical characteristics for use in implant-supported prostheses, particularly due to its fracture resistance and bone-like elastic modulus. However, the available evidence is predominantly based on in vitro and finite element studies. Long-term clinical trials are required to confirm its clinical performance and establish definitive recommendations for routine use. Full article

Background: Rehabilitation of edentulous mandibles in a post-oncologic setting remains a major clinical challenge. In such situations, placement of conventional endosseous implants may be compromised by severe bone deficiency, a history of peri-implant infection, and constraints related to reconstructive soft tissues. Customized titanium subperiosteal implants, made possible by three-dimensional imaging, computer-aided design, and additive manufacturing, represent a potential alternative when conventional options are unfavorable. This case report describes a full-arch fixed rehabilitation of an edentulous mandible in a patient previously treated for squamous cell carcinoma of the floor of the mouth. Methods: A patient-specific titanium additively manufactured subperiosteal jaw implant (AMSJI) made of biocompatible titanium was designed using a digital planning workflow. Implant placement was performed in a single surgical session under general anesthesia, with fixation using osteosynthesis screws. A screw-retained full-arch provisional prosthesis was delivered intraoperatively, allowing immediate loading with adjustments aimed at avoiding compression of the healing soft tissues. Results: The patient achieved satisfactory functional and esthetic rehabilitation. Postoperative follow-up showed overall favorable mucosal tolerance; an early, limited peri-abutment mucosal dehiscence was observed and managed with suturing under local anesthesia, without compromising implant stability. Conclusions: This case highlights the clinical interest of patient-specific titanium subperiosteal implants as a fixed rehabilitation option in post-oncologic patients with major osseous and mucosal constraints and a history of reconstructive procedures. The combination of accurate digital planning and custom-made manufacturing may avoid the need for extensive bone grafting. However, these findings should be interpreted with caution due to the short-term follow-up and the inherent limitations of a single-case report, which limit the level of evidence and generalizability. Full article

Microleakage at the implant–abutment interface represents a potential pathway for bacterial penetration and may contribute to peri-implant inflammation, marginal bone loss, and mechanical complications such as screw loosening. The increasing clinical use of compatible prosthetic abutments as cost-effective alternatives to original components has raised concerns regarding their fit, sealing capacity, and mechanical stability at this interface. The aim of this in vitro study was to evaluate differences in sealing capacity and torque loss between original and non-original abutments in a mixed internal connection implant system and to investigate the applicability of a novel quantitative approach for assessing microleakage based on a hydraulic conductance perfusion system. Nine abutments, including four multi-unit and five screw-retained cementable abutments, were connected to Straumann Bone Level implants at two tightening torques (5 N·cm and 35 N·cm). Microleakage was quantified by measuring fluid transport across the implant–abutment interface using the perfusion system, and removal torque values were recorded after testing. Non-original abutments exhibited significantly greater microleakage than original abutments at both torque levels. Microleakage increased significantly when the installation torque was reduced to 5 N·cm. At the manufacturer-recommended torque, screw-retained cementable abutments demonstrated higher microleakage than multi-unit abutments. Non-original abutments also showed significantly greater torque loss. These findings suggest that original abutments provide improved sealing capacity and mechanical stability at the implant–abutment interface, while the hydraulic conductance perfusion system represents a promising quantitative tool for investigating microleakage. Full article

The increasing prevalence of peri-implantitis has led to a growing clinical use of implantoplasty, a procedure involving intraoral machining of the dental implant surface to remove biofilm. The absence of standardized clinical protocols may contribute to premature fatigue failure of dental implants. The present study aimed to evaluate the influence of machining depth on the cyclic mechanical behavior of dental implants. A total of 250 commercially pure grade 4 titanium dental implants were distributed into four groups according to machining depth: untreated (original), 0.2 mm, 0.4 mm, and 0.6 mm wall reduction. The implant system featured an internal connection with a thread height of 0.4 mm. Finite element analysis was performed for each machining depth to evaluate von Mises stress distribution and simulate fatigue behavior. The numerical models were validated through experimental fatigue testing using a servo-hydraulic MTS Bionix testing machine under ISO 14801:2016 conditions, showing a high correlation between simulated and experimental results (correlation coefficients > 0.9). The results indicated that maximum von Mises stresses were concentrated at the junction between the implant thread and the implant body. The fatigue limit of the untreated implants was approximately 351 N. Implants subjected to 0.4 mm machining exhibited a fatigue limit of 301 N, whereas lower fatigue limits were observed for 0.2 mm (255 N) and 0.6 mm (185 N) reductions. These findings suggest a significant mechanical effect of thread removal: 0.4 mm implantoplasty may provide improved fatigue performance compared to 0.2 mm, potentially due to reduced stress concentration at the thread–body junction. At high applied loads, fracture occurred in the coronal region of the implant, whereas at lower loads failure shifted to the implant–abutment connection. Although a good agreement between numerical and experimental results was observed, these findings should be interpreted with caution due to the in vitro testing conditions and the assumptions inherent to the finite element simulations. Therefore, while the results suggest that implantoplasty depth should not exceed the original thread height, further validation under clinically relevant conditions is required to confirm its impact on long-term mechanical reliability. Full article

Objectives: This study aimed to evaluate the masking ability of different thicknesses of advanced lithium disilicate (ALDS) ceramic used for implant-supported crowns compared to conventional lithium disilicate (LDS) and to assess the influence of their combination with various implant abutment materials. Methods: Two types of high-translucency computer-aided design/computer-aided manufacturing (CAD/CAM) glass–ceramics in shade A2 were tested: IPS e.max CAD (LDS) and CEREC Tessera (ALDS). Each material was sectioned into four thicknesses (n = 8 per group). Four implant abutments were evaluated: titanium (Ti), yellow-anodized titanium (TiY), pink-anodized titanium (TiP), and white zirconia (Zir). The translucency parameter (TP₀₀) and color difference (ΔE₀₀) between the glass–ceramic and abutment were calculated using the CIEDE2000 formula. Results: Significant differences were observed between 1.0 mm and 2.5 mm thicknesses in all groups except for ALDS on TiY. Both glass–ceramics on TiY and TiP showed lower ΔE00 values than those on Ti, except for 2.0 mm and 2.5 mm ALDS. Additionally, their ΔE00 values were lower than those on Zir. Clinically acceptable ΔE₀₀ values occurred for 2.5 mm LDS on TiP, 2.0 mm ALDS on TiY and TiP, and 2.5 mm ALDS on TiY and TiP. ALDS demonstrated lower TP₀₀ values than LDS at corresponding thicknesses. Conclusions: Greater restoration thickness and titanium anodization improved color masking. Anodized titanium enhanced the glass–ceramic masking ability. ALDS at 2.0–2.5 mm on TiY or TiP and 2.5 mm LDS on TiP achieved clinically acceptable masking, with ALDS showing lower translucency than LDS. Full article

Objectives: To evaluate the influence of two surface finishing procedures—mechanical polishing and glaze firing—on the color stability and wear behavior of lithium aluminium disilicate (LAD) hybrid abutment crowns over a three-year clinical observation period. Methods: Twenty-four patients requiring 34 implant-supported single crowns were included in this prospective clinical study. LAD abutment crowns were fabricated using n!ce ceramic and a CAD/CAM workflow and finished either by mechanical polishing (P, n = 17) or glaze firing (G, n = 17). After insertion as well as after one and three years (P: n = 9, G: n = 9) of clinical use color measurements were performed using spectrophotometry, and color differences (ΔE00) were calculated. Wear was assessed by digital surface comparison of baseline and the two follow-up scans using three-dimensional analysis software. Reference teeth (R) were defined and evaluated comparable to the P and F groups. Biological and technical complications were recorded throughout the observation period. Results: Color deviations increased over time in all groups (P, G, R). After three years, G showed lower mean color differences (ΔE00 ≈ 2.77) compared with F (ΔE00 ≈ 5.40), although the difference was not statistically significant. No significant differences in vertical height loss were observed between P and G. One adhesive fracture occurred both in the P and G group, five crowns (P: n = 3, G: n = 2) developed periimplantitis. Conclusions: Both polishing and glazing resulted in comparable clinical outcomes regarding color stability, wear behavior, and complication rates. Clinical significance: Both finishing protocols might be a reliable option for LAD hybrid abutment crowns. Full article

Background/Objectives: The clinical decision between preserving periodontally compromised teeth and replacing them with dental implants represents a complex clinical dilemma influenced by biological, prosthetic, economic, and professional factors. The aim of this pilot study was to develop and preliminarily validate a questionnaire designed to assess dentists’ attitudes and therapeutic preferences regarding the use of periodontally compromised teeth as prosthetic abutments versus extraction and implant-supported rehabilitation. Methods: An observational cross-sectional study was conducted, among Romanian dentists, using a structured self-administered questionnaire consisting of 43 items organized into seven sections addressing clinical attitudes, decision-making factors, professional competence, prosthetic treatment preferences, and implant-related clinical practices. A total of 111 Romanian dentists completed the questionnaire. Responses were recorded using a five-point Likert scale. Statistical analysis was performed using IBM SPSS Statistics software. Internal consistency was evaluated using Cronbach’s alpha coefficient and intraclass correlation coefficient (ICC). Construct validity was assessed using exploratory factor analysis based on Principal Component Analysis with Varimax rotation. Results: The questionnaire demonstrated good internal consistency across most sections, with Cronbach’s alpha values ranging between 0.795 and 0.859 after scale optimization. Item–total correlations indicated adequate contribution of individual items to overall scale reliability. Intraclass correlation coefficients confirmed moderate reliability for individual items and good reliability for average section scores. Exploratory factor analysis showed satisfactory sampling adequacy (KMO = 0.709) and statistically significant Bartlett’s test of sphericity (p < 0.001), supporting the suitability of the data for factor analysis. The sample population was predominantly composed of early-career dentists with limited clinical experience, which should be considered when interpreting the findings. Conclusions: The developed questionnaire demonstrated satisfactory psychometric properties, including good internal consistency and acceptable construct validity, supporting its use as a research instrument for assessing Romanian dentists’ self-reported attitudes, therapeutic preferences, and perception-based decision patterns regarding the preservation of periodontally compromised teeth and implant-supported prosthetic rehabilitation. Full article

Background: Screw loosening remains a common mechanical complication in implant-supported restorations; however, the combined effect of sealing and superstructure materials on abutment screw stability warrants further investigation. Methods: This study evaluated the influence of access channel sealing material and superstructure material on abutment–implant screw stability after thermomechanical cyclic loading. Forty-eight Straumann analog–abutment assemblies restored with monolithic zirconia or resin nano-ceramic (Cerasmart) crowns were assigned to two sealing protocols: Polytetrafluoroethylene (PTFE) + composite or polyvinyl siloxane (PVS) putty (n = 12). After 750,000 off-axis cycles, reverse torque values (RTV) were analyzed using two-way analysis of variance (ANOVA) and Tukey’s HSD, with effect sizes calculated (α = 0.05). Results: A significant interaction between restorative material and sealing protocol was observed (p = 0.0170; η² = 0.116). Superstructure material showed no significant influence on RTV (p = 0.8368), whereas sealing protocol had a significant main effect (p = 0.0499). RTVs were highest for zirconia + PVS putty (36.33 ± 4.53 Ncm) and lowest for zirconia + PTFE (29.32 ± 6.30 Ncm), while the Cerasmart groups showed intermediate values. Post hoc analysis confirmed higher RTV for zirconia + PVS compared with zirconia + PTFE (p = 0.0138). Conclusions: Access channel sealing materials showed a material-dependent influence on abutment screw stability. Silicone-based sealing improved torque maintenance in zirconia, indicating that rigid restorative materials may be more sensitive to sealing material selection. In contrast, Cerasmart showed comparable RTV regardless of sealing protocol, suggesting that resilient restorative materials may reduce the influence of sealing on preload maintenance. Full article

Background/Objectives: Prosthodontic restoration design plays a key role in the long-term success of implant-supported treatments and in maintaining peri-implant tissue health. Inadequate emergence angles and profiles can compromise tissue stability and negatively influence clinical outcomes. Generative design, as an algorithm-driven optimization approach, requires the definition of key parameters in advance to guide the process and determine the final shape of the hybrid implant abutment. Methods: A detailed literature review of the PubMed and Scopus databases was performed to find appropriate studies published up to 1 December 2025. Studies that investigated the emergence angle and emergence profile of implant-supported restorations were included. Seventeen studies fulfilled criteria and were included in the final analysis. Results: While the optimal emergence angle is still debatable, the literature suggests that an angle less than 30° may be beneficial. However, a concave emergence profile of implant-supported restoration has a significant role in improving stability and maintaining peri-implant health. Conclusions: Careful characterization and evaluation of the included parameters provide useful insights for generative design workflows, enabling the creation of implant abutment designs that maintain a balance between mechanical performance and biological compatibility. Full article

Zygomatic implant perforated (ZIP) flap reconstruction offers immediate surgical rehabilitation following maxillectomy, integrating oncologic zygomatic implants with a fascio-cutaneous free flap. A critical technical challenge is safely perforating the free flap skin paddle to accommodate implants’ abutments without damaging its vasculature. Near-infrared (NIR) vein visualization technology provides real-time mapping of subcutaneous vessels and has been widely investigated in settings such as pediatric intravenous (IV) cannulation. By projecting vein pathways onto the skin, NIR visualization facilitates precise vascular identification, potentially reducing complications. We describe a case of ZIP flap reconstruction in a 25-year-old patient utilizing NIR vein visualization to preemptively locate flap vasculature and minimize the risk of vessel puncture. Our discussion places these findings within the context of the existing literature on NIR devices, underscoring their benefits of non-invasive operation, rapid imaging, and minimal need for advanced operator skills, and highlighting their utility in microvascular reconstructive surgery. Full article

Background: Implant therapy is a standard of care for long-term tooth replacement. While high survival rates have been reported for implants placed by specialists, data on outcomes achieved by Advanced Education in General Dentistry (AEGD) residents remain limited. Objectives: To evaluate the clinical performance and complication rates of dental implants placed and restored by AEGD residents under faculty supervision, and to identify factors influencing outcomes after at least one year in function. Methods: A retrospective review was conducted for implants placed between April 2012 and December 2021 at the Eastman Institute for Oral Health. Only implants with ≥1-year follow-up were included. Data included demographics, medical history, smoking status, oral hygiene, peri-implant health, and prosthetic outcomes. Logistic regression was used to assess associations between risk factors and complications. Results: Among 262 implants that survived ≥1 year, the complication rate was low: screw loosening occurred in 8.4%, crown issues in 3.4%, abutment or screw fractures in 0.4%, and early peri-implantitis in 11.5%. Examiner satisfaction was high for esthetics (82.8%) and occlusion (85.9%), and over 80% of patients rated their outcomes between 8 and 10 on a 10-point scale. Diabetes and high plaque index were significant predictors of peri-implantitis. Conclusions: Implants placed and restored by AEGD residents under structured faculty supervision achieved low complication frequencies, and strong patient satisfaction comparable to specialist outcomes. Full article

The lack of integrity at the implant–abutment junction (IAJ) contributes to problems such as micromovements and microbial colonisation. This study aimed to (1) design a protocol for assessing microleakage at the IAJ using chromophore analysis not previously reported for this specific application, (2) compare gas and dye leakage between titanium (Ti) and cobalt chrome (CoCr) abutments, and (3) assess the effect of gold (Au) gilding on sealing. Forty abutments were divided into five groups: milled Ti (MTi); cast CoCr (CCoCr); milled CoCr (MCoCr); cast CoCr with Au gilding (CCoCrG); and milled CoCr with Au gilding (MCoCrG). Samples were subjected to internal pressure within a gas and dye reservoir. Chromophore analysis via UV-Vis spectrometer was used to calculate crystal violet leakage concentrations. Scanning electron microscopy (SEM) revealed close adaptation in the MTi and MCoCr groups, contrasting with irregularities in the CCoCr groups. Correspondingly, gas leakage and dye leakage were most prevalent in the CCoCr group. Fisher exact test demonstrated a statistically significant difference (p = 0.026) between the MCoCr and CCoCr abutments. While CCoCr exhibited the highest failure rate (62.5%), Au gilding demonstrated a trend toward reduced leakage (25% failure rate), though this did not reach statistical significance (p = 0.315). This chromophore analysis represents a viable and objective assessment of IAJ integrity. Full article

Objective: To evaluate the biomechanical effects of varying posterior implant inclinations and loading protocols on peri-implant stress distribution in full-arch maxillary rehabilitations using the All-on-Four concept. Methodology: A three-dimensional finite element model of an edentulous atrophic maxilla was developed from a digital point cloud. Four implants were placed according to the All-on-Four protocol: two anterior vertical implants and two posterior implants with inclinations of 0°, 15°, 30°, or 45°. Mini-abutments and a titanium bar prosthesis were included. Material properties were assumed as homogeneous, isotropic, and linearly elastic. Immediate loading was simulated using frictional contacts (µ = 0.3), whereas delayed loading assumed complete osseointegration (bonded contacts). The models were meshed using 10-node quadratic tetrahedral elements (SOLID187) in ANSYS^®. Maximum von Mises stress in cortical bone, cancellous bone, implants, abutments, and the prosthetic bar was assessed. Results: Posterior implant tilt significantly reduced peri-implant stress. Under immediate loading, the highest stress occurred at 0° inclination in the posterior left implant (82.36 MPa) and decreased progressively with increasing tilt, reaching 33.63 MPa at 45° (≈59% reduction). Delayed loading generally produces lower stress magnitudes, particularly at extreme tilts. Anterior implants experienced lower stress levels across all configurations. Comparative analysis demonstrated that immediate loading increased stress at lower angulations, while differences between loading protocols were minimal at higher inclinations. Conclusions: Posterior implant angulation and loading protocol critically influence peri-implant stress distribution. Increased posterior tilt combined with appropriate loading reduces peak cortical bone stresses, supporting biomechanical optimization in All-on-Four maxillary rehabilitations. Full article