Search Results (55)

Background and Clinical Significance: Immediate implant placement in mandibular molars represents a clinical challenge due to lower trabecular bone density and anatomical limitations of the interradicular septum. Osseodensification has been proposed as an alternative to improve primary stability in sites with low bone quality. Case Presentation: This report describes the case of a 54-year-old female patient with a mesial root fracture in the lower right first molar, treated by atraumatic extraction followed by immediate implant placement using a densifying drilling protocol. After careful root removal, the interradicular septum was expanded using Versah burs at 1200 rpm, allowing placement of a 4.0 × 7 mm Implacil Duecone implant with a final insertion torque of 25 Ncm. The residual gap was filled with a xenogeneic bone substitute and covered with a dense polytetrafluorethylene membrane for alveolar preservation. Healing progressed uneventfully and, after four months, adequate bone formation was observed, enabling prosthetic rehabilitation with a single ceramic crown. After 4 postoperative years we could find peri-implant tissue stability. Conclusions: The clinical outcome supports current evidence indicating that osseodensification may enhance initial stability and predictability of immediate implants placed in posterior mandibular regions. Full article

Accurate transfer of implant position is essential for implant-supported prosthodontic workflows. This in vitro study compared the trueness and precision of five intraoral scanners in single crown, three-unit fixed partial denture, and full-arch implant-supported scanning scenarios using root mean square (RMS) deviation analysis. Two maxillary resin models, representing partially dentulous and fully edentulous conditions, were fabricated through a CAD/CAM and 3D-printing workflow with implant analogs and scan bodies. Reference datasets were obtained with an InEos X5 desktop scanner, and each intraoral scanner was used to perform 10 scans per scenario. After standardized scenario-specific trimming, datasets were analyzed in Geomagic Control X. Statistical analysis included two-way analysis of variance and follow-up one-way analysis of variance with Tukey post hoc comparisons using Bonferroni-adjusted thresholds. Trueness was affected by scanner type (p < 0.001) and scenario (p < 0.001), without interaction (p = 0.096). Precision was affected by scanner type (p = 0.012), scenario (p = 0.004), and their interaction (p < 0.001). iTero Lumina and Helios 600 showed lower trueness deviations, whereas Trios 5 showed greater deviations, especially in full-arch scans. Scanner selection and scan extent should therefore be considered when interpreting surface-based RMS accuracy in implant-supported digital scans. Full article

Background: The White Esthetic Score (WES) is a standardized clinician-reported index that assesses the esthetic quality of a single-tooth restoration by comparison with a natural reference tooth, typically the contralateral tooth. It evaluates five domains: tooth form, crown outline/volume, color (hue/value), surface texture, and translucency/characterization. Each domain is scored from 0 to 2 (major discrepancy, minor discrepancy, no discrepancy), yielding a total score of 0–10; higher scores indicate a closer match. Although developed for single-tooth implant restorations, WES has also been applied to natural teeth and tooth-supported restorations. Methods: This comprehensive review summarizes case-report evidence applying WES to tooth-supported restorations, outlining the concept, scoring method, documentation requirements, and available data on reliability and interpretation. A case illustration is also presented in which a patient received eight anterior veneers; outcomes were assessed using all WES parameters. Results: Published reports support WES as a practical qualitative tool to assess esthetic outcomes in tooth-supported restorations. In the presented case, the veneers achieved a WES of 9, reflecting marked improvement in tooth form, crown outline/volume, color, surface texture, and translucency/characterization. Conclusions: The comprehensive review indicates WES is feasible for routine clinical use in practice, but agreement varies by parameter and improves with standardized photography and examiner calibration; some components show lower inter-rater agreement than simpler soft-tissue indices. Because correlations between WES and patient satisfaction are inconsistent, WES should be complemented with patient-reported outcome measures. Common thresholds consider WES ≥ 6 acceptable. Clinical use for crowns and veneers should emphasize case selection, standardized records, and combined clinician- and patient-centered outcome reporting. Full article

Background/Objectives: Titanium implants remain the gold standard in implant dentistry. However, growing interest in metal-free alternatives has led to increased use of zirconia implants. Despite encouraging short-term outcomes, evidence regarding the medium- to long-term survival of one-piece zirconia implants (O-PZIs) and associated risk factors remains limited. The aim of this retrospective cohort study was to evaluate the survival of O-PZIs over follow-up periods of up to 8 years and to explore variables potentially associated with implant failure. Methods: This retrospective observational cohort study was conducted at a private dental clinic (Madrid, Spain). A total of 307 O-PZIs placed in 196 patients between 2017 and 2021 were analyzed. Implant survival was assessed using Kaplan–Meier analysis, while associations between clinical variables and implant failure were explored using chi-square tests and multivariate Cox regression models (p < 0.05). The mean follow-up period was 61.37 ± 2.25 months. Results: After a mean follow-up of 61.37 ± 2.25 months (range: 39–96 months), 42 failures were recorded, resulting in a cumulative survival rate of 86.32% (CI 95%: 79.28–92.96%). Most failures (64.29%) occurred before prosthetic loading. Kaplan–Meier analysis revealed significantly lower survival for tapered implants (p < 0.001) and among smokers (p < 0.001). Multivariate analysis indicated that only simultaneous guided bone regeneration (GBR) was independently associated with implant failure (Exp(B) = 3.191; 95% CI: 1.299–7.840; p = 0.011). However, this association should be interpreted with caution due to the retrospective design, potential confounding, limited number of events, and lack of adjustment for clustering at the patient level. The discrepancies observed between statistical methods highlight the importance of time-to-event analyses in implant research. Conclusions: Within the limitations of this study, O-PZIs demonstrated acceptable medium- to long-term survival. Simultaneous GBR may be associated with increased risk of failure. However, these findings should be considered exploratory. Further prospective studies are required to confirm these results and to better define risk factors in ceramic implant therapy. 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

Deep learning is increasingly integrated into oral rehabilitation workflows, particularly in implant planning, prosthodontic design automation, and peri-implant diagnosis. However, reported performance is heterogeneous and difficult to compare across tasks, modalities, and validation designs. The goal of this study was to critically analyze deep learning architecture families applied to oral rehabilitation and to provide task-driven selection guidance supported by an evidence table reporting dataset characteristics, validation strategy, and performance metrics. A focused narrative review was conducted using transparent, database-specific search criteria (final n = 10 included studies), emphasizing implant planning (cone–beam computed tomography [CBCT]-based segmentation), prosthodontic design (intraoral scan [IOS]/mesh inputs), and peri-implant diagnosis (periapical/panoramic radiographs). Evidence certainty for each clinical task was assessed using GRADE-informed ratings (High/Moderate/Low/Very Low). Extracted variables included clinical task, imaging modality, dataset size, architecture, validation strategy (internal vs. internal + external), split level, ground truth protocol, and performance metrics. A structured computational and hardware feasibility analysis was conducted for each architecture family to support real-world deployment planning. Encoder–decoder networks (U-Net/nnU-Net) dominate CBCT segmentation for implant planning, while detection architectures (Faster R-CNN, YOLO) support implant localization and peri-implant assessment on radiographs. Generative models (3D GANs, transformer-based point-to-mesh networks) enable crown design from three-dimensional scans. Hybrid CNN–Transformer architectures show promise for multimodal CBCT–IOS fusion, though direct evidence from the included studies remains limited to a single study. External validation remains uncommon yet essential given the risk of domain shift. In conclusion, architecture selection should be anchored to task geometry (2D vs. 3D), artifact burden, and required clinical output type. Reporting standards should prioritize dataset transparency, validation rigor, multi-center external testing, and uncertainty-aware outputs. Full article

Background/Objectives: The purpose of this study was to investigate the laser removal of implant-supported ceramic single crowns, focusing on their efficiency and the potential reusability of the removed restorations. Methods: Sixty single crowns made of lithium disilicate were adhesively bonded to prefabricated titanium abutments in a total of six test series (n = 10). The test series were divided according to the different spacer settings of the crowns (90 µm, 120 µm, 150 µm) and the taper of the abutments (4°, 6°). After seven days of storage in distilled water, the single crowns were removed using an erbium-doped yttrium aluminium garnet (Er:YAG) laser. The number of laser pulses needed and the time required to remove the crowns were recorded. This was followed by a micro- and macroscopic score evaluation of the crowns using a fluorescent penetration method. Results: Laser removal of all sixty crowns was successfully performed. Using a taper of 6° and a spacer of 150 µm, the crowns were removed with significantly fewer pulses (61.40 (±36.78)). The taper and spacer had a significant effect on both the microscopic (p = 0.040) and macroscopic (p = 0.035) fracture patterns. Based on the final score of the fracture analysis, 44 of the 60 crowns could be classified as potentially reusable. The remaining 16 crowns failed due to purely macroscopic (7), purely microscopic (6), and combined microscopic and macroscopic (3) fracture behavior. Conclusions: Based on the results of this study, increasing the size of the taper and spacer has proven beneficial for laser removal in terms of time efficiency and non-destructive removal of crowns. Full article

Objectives: To compare artificial intelligence (AI) crown design with expert or non-AI computer-aided (CAD) design for single-unit tooth and implant-supported crowns across efficiency, marginal and internal fit, morphology and occlusion, and mechanical performance. Materials and Methods: This systematic review was conducted and reported in accordance with PRISMA 2020. PubMed MEDLINE, Scopus, Web of Science, IEEE Xplore, and Dentistry and Oral Sciences Source were searched from 2016 to 2025 with citation chasing. Eligible studies directly contrasted artificial intelligence-generated or artificial intelligence-assisted crown designs with human design in clinical, ex vivo, or in silico settings. Primary outcomes were design time, marginal and internal fit, morphology and occlusion, and mechanical performance. Risk of bias was assessed with ROBINS-I for non-randomized clinical studies, QUIN for bench studies, and PROBAST + AI for computational investigations, with TRIPOD + AI items mapped descriptively. Given heterogeneity in settings and endpoints, a narrative synthesis was used. Results: A total of 14 studies met inclusion criteria, including a clinical patient study, multiple ex vivo experiments, and in silico evaluations. Artificial intelligence design reduced design time by between 40% and 90% relative to expert computer-aided design or manual workflows. Marginal and internal fit for artificial intelligence and human designs were statistically equivalent in multiple comparisons. Mechanical performance matched technician designs in load-to-fracture testing, and modeling indicated stress distributions similar to natural teeth. Overall risk of bias was judged as some concerns across tiers. Conclusions: Artificial intelligence crown design delivers efficiency gains while showing short-term technical comparability across fit, morphology, occlusion, and strength for single-unit crowns in predominantly bench and in silico evidence, with limited patient-level feasibility data. Prospective clinical trials with standardized, preregistered endpoints are needed to confirm durability, generalizability, and patient-relevant outcomes, and to establish whether short-term technical advantages translate into clinical benefit. Full article

Background/Objectives: Zirconia-reinforced lithium silicate (ZLS) is a glass–ceramic that combines the translucency of lithium disilicate with the enhanced strength provided by dispersed zirconia crystals. Evidence on the mechanical behavior of ZLS implant-supported crowns remains limited. This study evaluated the fracture resistance of posterior monolithic ZLS crowns and analyzed the influence of cement type and artificial aging. Methods: Forty ZLS crowns (Celtra™ Duo) were fabricated, cemented onto straight titanium abutments and assigned to four groups (n = 10) according to cement type (adhesive or self-adhesive) and aging (500,000 cycles at 150 N). Specimens underwent axial load-to-fracture testing using a universal testing machine. Data were analyzed with Student’s t-tests and Kruskal–Wallis tests (α = 0.05). Results: Mean fracture resistance was 1625.46 ± 340.02 N. Although adhesive cement showed higher mean values than self-adhesive cement, no statistically significant differences were found (p = 0.102). Artificial aging also produced no significant reduction in fracture resistance (p = 0.674). All groups exceeded the physiological posterior occlusal forces. Conclusions: Monolithic ZLS crowns cemented onto titanium abutments demonstrated high fracture resistance under axial loading. Within the limitations of this in vitro design, neither cement type nor mechanical aging significantly affected performance. These findings support the mechanical feasibility of ZLS for posterior implant-supported single crowns, although further studies including thermomechanical aging and oblique loading are required. Full article

Background/Objectives: Artificial intelligence (AI) has been increasingly used to support radiological assessment in dentistry. We benchmarked machine learning (ML), deep learning (DL), and a hybrid optimization-assisted approach for the automatic five-class image-level classification of dental restorations (filling, implant, root canal treatment, fixed partial denture/bridge, crown) on panoramic radiographs. Methods: We analyzed 353 anonymized panoramic images comprising 2137 labeled restorations, acquired on the same device. Images were cropped and enhanced (histogram equalization and CLAHE), and texture features were extracted with GLCM. A three-stage pipeline was evaluated: (i) GLCM-based features classified by conventional ML and a baseline DL model; (ii) Hybrid Grey Wolf–Particle Swarm Optimization (HGWO-PSO) for feature selection followed by SVM; and (iii) a CNN trained end-to-end on raw images. Performance was assessed with an 80/20 per-patient split and 5-fold cross-validation on the training set. While each panoramic radiograph may contain multiple restorations, in this study we modeled the task as single-label, image-level classification (dominant restoration type) due to pipeline constraints; this choice is discussed as a limitation and motivates multi-label, localization-based approaches in future work. The CNN baseline was implemented in TensorFlow 2.12 (CUDA 11.8/cuDNN 8.9) and trained with Adam (learning rate 1 × 10⁻⁴), with a batch size 32 and up to 50 epochs with early stopping (patience 5); data augmentation included horizontal flips, ±10° rotations, and ±15% brightness variation. A post hoc power analysis (G*Power 3.1; α = 0.05, β = 0.2) confirmed sufficient sample size (n = 353, power > 0.84). Results: The HGWO-PSO + SVM configuration achieved the highest accuracy (73.15%), with macro-precision/recall/F1 = 0.728, outperforming the CNN (68.52% accuracy) and traditional ML models (SVM 67.89%; DT 59.09%; RF 58.33%; K-NN 53.70%). Conclusions: On this single-center dataset, the hybrid optimization-assisted classifier moderately improved detection performance over the baseline CNN and conventional ML. Given the dataset size and class imbalance, the proposed system should be interpreted as a decision-supportive tool to assist dentists rather than a stand-alone diagnostic system. Future work will target larger, multi-center datasets and stronger DL baselines to enhance generalizability and clinical utility. Full article

Background: The implant–abutment interface has been thoroughly examined due to its impact on the success of implant healing and longevity. Removing the abutment is advantageous, but it changes the biomechanics of the implant fixture and restoration. This in vitro three-dimensional finite element analytical (FEA) study aims to evaluate the distribution of von Mises stress (VMS) in abutment-free and three additional implant abutment connections composed of various titanium alloys. Materials and methods: A three-dimensional implant-supported single-crown prosthesis model was digitally generated on the mandibular section using a combination of microcomputed tomography imaging (microCT), a computer-assisted designing (CAD) program (SolidWorks), Analysis of Systems (ANSYS), and a 3D digital scan (Visual Computing Lab). Four digital models [A (BioHorizons), B (Straumann AG), C abutment-free (Matrix), and D (TRI)] representing three different functional biomaterials [wrought Ti-6Al-4Va ELI, Roxolid (85% Ti, 15% Zr), and Ti-6Al-4V ELI] were subjected to simulated static/cyclic static loading in axial/oblique directions after being restored with highly translucent monolithic zirconia restoration. The stresses generated on the implant fixture, abutment, crown, screw, cortical, and cancellous bones were measured. Results: The highest VMSs were generated by the abutment-free (Model C, Matrix) implant system on the implant fixture [static (32.36 Mpa), cyclic static (83.34 Mpa)], screw [static (16.85 Mpa), cyclic static (30.33 Mpa), oblique (57.46 Mpa)], and cortical bone [static (26.55), cyclic static (108.99 Mpa), oblique (47.8 Mpa)]. The lowest VMSs in the implant fixture, abutment, screw, and crown were associated with the binary alloy Roxolid [83–87% Ti and 13–17% Zr]. Conclusions: Abutment-free implant systems generate twice the stress on cortical bone than other abutment implant systems while producing the highest stresses on the fixture and screw, therefore demanding further clinical investigations. Roxolid, a binary alloy of titanium and zirconia, showed the least overall stresses in different loadings and directions. Full article

Background/Objectives: This single-center, randomized controlled clinical trial evaluated the impact of two crown materials—lithium disilicate (LS2) and a polymer-infiltrated hybrid ceramic (HC)—on the marginal bone loss (MBL) and the technical complications in implant-supported single-tooth restorations over a three-year period. Methods: Sixty patients with posterior single-tooth gaps were randomly assigned to receive either LS2 or HC crowns on iSy (Camlog) implants. All of the restorations were fabricated as CAD/CAM-based hybrid abutment crowns bonded to prefabricated titanium bases. Standardized radiographs were taken at the baseline (T0) and at three years (T1) to assess the MBL using ImageJ software. The technical complications were prospectively recorded. The data analysis was descriptive and exploratory. Results: Fifty-eight cases were available for the final evaluation. The three-year implant survival rate was 100%. The mean marginal bone remodeling was minimal (mesial: LS2 0.15 mm, HC 0.08 mm; distal: LS2 0.13 mm, HC 0.12 mm), with no statistically significant intergroup differences. Bone apposition was observed in 74.1% of the cases. The male patients showed a significantly greater mesial bone loss (p = 0.024). Technical complications occurred more frequently in the HC group, including crown fractures (25%), decementation (17.9%), and screw loosening (14.3%). In the LS2 group, only screw loosening (12.5%) was observed. Conclusions: The lithium disilicate-based hybrid abutment crowns demonstrated a high clinical reliability with stable peri-implant bone and fewer technical complications over three years. In contrast, the hybrid ceramic crowns were associated with a higher rate of mechanical failure. Material selection should therefore be a key consideration in planning implant-supported single-tooth restorations. Full article

This study aimed to evaluate prosthetic complications, implant survival rates, and marginal bone loss in implant-supported monolithic restorations compared to metal-ceramic restorations. The study was registered in PROSPERO (CRD420251022336) and conducted following the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA guidelines. A systematic search was conducted in the electronic databases MEDLINE/PubMed, Web of Science, Scopus, Embase, and ProQuest for articles published up to December 2024. The inclusion criteria comprised studies evaluating only randomized clinical trials that evaluated implant-supported monolithic restorations directly compared to metal-ceramic restorations, considering any type of ceramic material and regardless of the fixation system (screw-retained or cemented), with a minimum follow-up of one year. A meta-analysis was performed using RevMan 5.4 software, and the risk of bias and certainty of evidence were assessed using the RoB 2.0 and GRADE tools, respectively. A total of six studies were included, all of which exclusively evaluated monolithic zirconia single crowns over follow-up periods ranging from 1 to 3 years. None of the included studies evaluated fixed partial dentures or restorative materials other than monolithic zirconia. In total, 267 patients (mean age range: 18–57 years) were analyzed, with a total of 174 implant-supported monolithic zirconia crowns and 165 metal-ceramic single crowns in the posterior region (premolars and molars). The meta-analysis revealed that implant-supported monolithic zirconia single crowns exhibited significantly fewer prosthetic complications compared to metal-ceramic single crowns (p < 0.0001; Risk Ratio [RR]: 0.26; Confidence Interval [CI]: 0.14–0.47). However, no statistically significant differences were observed between implant-supported monolithic zirconia and metal-ceramic single crowns regarding implant survival rates (p = 0.36; RR: 1.66; CI: 0.56–4.94) or marginal bone loss (p = 0.15; Mean Difference [MD]: −0.05; CI: −0.11–0.02). The risk of bias assessment indicated that four studies had a low risk of bias. However, the certainty of evidence was classified as low for prosthetic complications and implant survival rates and very low for marginal bone loss. Within the limitations of this review, it can be concluded that implant-supported monolithic zirconia single crowns can be considered a favorable treatment option as they show comparable implant survival and bone stability to metal-ceramic crowns, with a potential reduction in short-term prosthetic complications such as screw loosening and ceramic chipping. However, due to the limited number of studies included and low certainty of evidence, further long-term research is still needed to confirm their clinical performance over time. Full article

Purpose: The aim of this study was to evaluate the long-term clinical results of two different implant–abutment connection types (screw-retained/Morse locking taper), marginal bone loss, and complications in prosthetic restorations. Materials and Methods: In 2017–2018, 579 implants and 242 implant-supported restorations applied to 137 patients were included in the study. Patients were recalled every six months, clinical evaluations were accomplished, and complications were recorded. When examining the distribution of prosthetic restorations by type, it was determined that 38 (15.70%) were single crowns, 136 (56.19%) were fixed partial cement-retained bridge restorations, 53 (21.90%) were fixed partial screw-retained bridge restorations, and 15 (6.19%) were overdenture prostheses. Findings: Overall, complications included eighteen (21.68%) retention losses, nineteen (22.89%) instances of screw loosening, twenty-one (25.30%) veneer ceramic fractures, three (3.61%) acrylic base fractures, fourteen (16.87%) cases of peri-implantitis, and eight (9.64%) implant losses. Conclusions: Differences in complication rates were observed between implants with different implant–abutment connection designs. While no significant differences were found regarding annual mesial and distal marginal bone loss for implants with conical locking connections, a significant difference was detected in those with screw-retained connections. In both implant groups, mesial and distal marginal bone loss progressed gradually over the follow-up period. Full article

The adaptation of restorations to the titanium base (TiBase) abutments varies depending on the materials and methods used, playing a crucial role in implant and prosthetic success. This in vitro study aims to compare the internal and marginal fit of a titanium interface among three different milled materials: doped graphene PMMA, single-density zirconia, and dual-density zirconia, used for the rehabilitation of CAD-CAM implant-supported single crowns. A digital method based on the silicone replica technique was employed. The silicone reproduction of each fabricated restoration’s inner and basal parts was digitally aligned to the titanium base, measuring the space between them at three predetermined planes: basal, middle, and superior. The material with the worst overall adaptation was dual-density zirconia (0.1 ± 0.03 mm), followed by single-density zirconia (0.09 ± 0.03 mm), and doped graphene PMMA (0.06 ± 0.02 mm). No statistical differences were found in the internal fit, represented by the measurements made at the middle and superior plane, among the materials used (p > 0.05). However, the marginal fit of doped graphene PMMA restorations was statistically better than zirconia restorations (p < 0.05). No significant differences were observed between the marginal fit of both types of zirconia (p > 0.05). Across all three materials, the superior plane showed the best fit, while the marginal plane exhibited the worst. Full article