Search Results (21)

Background: Rehabilitation of the severely atrophic posterior mandible remains challenging when the residual bone height above the inferior alveolar nerve (IAN) is insufficient for conventional implant placement. In such cases, IAN lateralization or transposition may facilitate placement of longer implants and support fixed prosthetic rehabilitation. However, these procedures require careful case selection because of their technical complexity and the risk of neurosensory complications. Objective: This narrative review presents a literature-informed, expert-derived, parameter-based clinical decision framework for preoperative planning of IAN lateralization and transposition in the severely atrophic posterior mandible. Methods: A focused appraisal of the literature was performed to identify anatomical, prosthodontic, and surgical parameters relevant to IAN repositioning. Parameters were selected according to their recurrent relevance to surgical feasibility, implant positioning, procedural safety, and restorative planning, and were integrated with the authors’ clinical experience to develop a structured decision-making framework. No formal risk-of-bias or certainty-of-evidence assessment was performed. Each parameter was assigned an evidence-source category and a threshold status to make its evidentiary basis explicit. Results: The proposed framework organizes treatment planning into three domains: bone-related, prosthodontic, and surgical considerations. Key parameters include residual bone height above the IAN canal, global mandibular height, ridge width, bone density, crown-to-implant ratio, intermaxillary space, ridge angulation, buccal cortical plate thickness, and the three-dimensional course of the IAN. Additional parameters include interforaminal dentition, implant trajectory, canal diameter, bifid canal anatomy, and ridge contour. Collectively, these variables are integrated into a stepwise decision pathway to help determine whether IAN repositioning is appropriate, whether lateralization or transposition is preferable, and when alternative approaches, such as short implants, ridge splitting, or vertical augmentation, may be more suitable. The framework links restorative feasibility and surgical risk to the choice of technique within a single sequential pathway, and reports the evidence basis of each decision point. Conclusions: The proposed framework should not be regarded as a validated clinical decision tool; prospective clinical validation and consensus-based refinement are required before routine clinical implementation. The framework is intended to structure and guide multidisciplinary assessment and discussion of cases; it should not independently determine treatment selection or replace individualized clinical judgment. Full article

This pilot in vitro study explored the tensile retention of lithium disilicate and monolithic zirconia crowns cemented onto zirconia one-piece implants using two resin cements and two cementation protocols. In addition, the relationship between micro-computed tomography (micro-CT)-derived cement layer characteristics and retention was explored for lithium disilicate crowns. Thirty-two implant–crown assemblies were prepared using 16 lithium disilicate and 16 zirconia crowns. Specimens were cemented with either an adhesive resin cement (Panavia V5) or a self-adhesive resin cement (SpeedCem Plus) using two protocols: conventional apical-half cementation (AH) and an abutment-assisted apical-half protocol (A-AH). Cement thickness and porosity for lithium disilicate crowns were obtained from a previously published micro-CT analysis of the same specimens; no micro-CT measurements were available for the zirconia specimens. Tensile pull-out testing was performed using a universal testing machine. The primary outcome was the maximum recorded force at the first observed mechanical failure, irrespective of the mode of that failure, so that all 32 specimens contributed a value. Failure occurred by crown debonding in 27 specimens, by crown fracture in 4 and by implant fracture in 1. For the primary outcome, the maximum recorded force was lower for lithium disilicate than for zirconia crowns (medians 347.20 versus 596.05 N; exact Mann–Whitney p = 0.017) and lower with the A-AH than with the AH protocol (medians 304.24 versus 614.38 N; p < 0.001), whereas the difference between the two resin cements was not statistically significant (medians 438.88 versus 550.83 N; p = 0.210). The highest observed mean maximum load was recorded for zirconia crowns cemented with Panavia V5 using the AH protocol (729.9 ± 237.7 N), whereas the lowest observed mean maximum load was recorded for lithium disilicate crowns cemented with Panavia V5 using the A-AH protocol (219.7 ± 105.1 N). In a secondary, cause-specific exploratory analysis restricted to crown debonding (27 events, 5 specimens censored at fracture), Cox proportional hazards regression on the applied-force scale gave hazard ratios of 3.75 (95% CI 1.40–10.01) for lithium disilicate versus zirconia, 6.47 (2.39–17.53) for A-AH versus AH and 1.82 (0.76–4.39) for Panavia V5 versus SpeedCem Plus. For lithium disilicate crowns, exploratory factorial ANOVA indicated that cementation protocol was associated with differences in cement thickness (p = 0.035), while cement type was associated with differences in porosity (p < 0.001). All 16 lithium disilicate cement thickness observations lay between 253.29 and 254.96 µm, a total span of 1.67 µm. Within that extremely restricted range, a univariable exploratory Cox model expressed per 0.1 µm gave a hazard ratio for debonding of 1.24 (95% CI 1.03–1.48; p = 0.024); this is an unadjusted association across a range that is itself associated with cementation protocol, and it does not demonstrate a clinically meaningful or independent effect of cement thickness. No association was detected for total porosity (0.959 per percentage point, 0.717–1.283); that interval is wide and indicates absence of evidence rather than evidence of no association. Within the limitations of this pilot in vitro study—four specimens per subgroup, wide confidence intervals and no adjustment for multiplicity—the findings suggest that crown material and cementation protocol may be associated with retention patterns. They are exploratory and hypothesis-generating and require confirmation in larger, independently powered studies. Full article

Prosthetic factors, including abutment angulation and the crown–implant ratio (CIR), have been suggested to influence peri-implant marginal bone loss; however, their long-term effects remain unclear. This study aimed to evaluate the pattern of peri-implant bone loss over 2 years and to analyze the clinical relevance of abutment angulation and CIR. A total of 200 posterior internal-connection implants placed between 2017 and 2021 were retrospectively evaluated using standardized periapical radiographs taken at baseline, 6 months, 1 year, and 2 years after loading. Bone level changes were measured mesially and distally and average per implant. Patients were categorized according to abutment angulation (<30° or ≥30°) and CIR (<1:1.5 or ≥1:1.5). The mean marginal bone loss increased during the first year (0.61 mm at 6 months to 1.08 mm at 1 year) and remained stable thereafter (1.12 mm at 2 years). Significantly greater bone loss was observed in implants restored with abutment angulation ≥ 30° (p < 0.05), whereas CIR showed no significant association at any time point (p > 0.05). No interaction effect was found between the two variables. Most peri-implant bone remodeling occurred within the first year after loading, followed by a stable phase. Abutment angulation of ≥30° was associated with increased bone loss, while CIR alone did not demonstrate clinical significance. When possible, minimizing abutment angulation may help improve long-term peri-implant bone stability. Full article

Background/Objectives: Chipping of the veneering part of the crown at the zirconia–porcelain interface remains a major complication of bilayered zirconia systems. This systematic review evaluated whether incorporating a lithium-disilicate (LD) liner or press-on or CAD-on interlayer between zirconia and veneer improves bond strength and fracture performance in vitro. Methods: Following PRISMA 2020, we searched PubMed, Scopus, and Web of Science up to 7 September 2025 for open-access English in vitro studies using LD-based interlayers at zirconia–veneer interfaces and reporting quantitative bond and/or fracture outcomes. Data included extracted materials, processing parameters, and mechanical results; due to heterogeneity, findings were synthesized descriptively and as the ratio-of-means (ROM). Results: Five in vitro studies from Korea, Thailand, and India met the criteria. LD interlayers increased microtensile bond strength from 18.83 to 44.20 MPa and from 19.6 to 47.7 MPa, and shear bond strength from 41.3 to 59.7 MPa, 11.40 ± 1.29 to 18.81 ± 1.76 MPa, and 21.5 to 60.2 MPa. Corresponding ROMs ranged from 1.46 to 2.80 (median 2.35), with thermocycled LD groups maintaining strengths >25 MPa. LD liners also raised crown fracture loads from ~2.18 to ~3.45 kN and characteristic strength from 3.42 to 5.64 kN, while chipping loads in implant crowns increased from ~0.34 to ~0.84 kN and global fracture from ~1.71 to ~1.93 kN. Conclusions: Across diverse zirconia–veneer configurations, LD interlayers consistently enhanced bond metrics and fracture/chipping resistance, supporting their use as a targeted interfacial strategy; however, clinical confirmation is still needed. Full article

The biomechanical performance of dental implants is affected by both abutment height and bone quality, which influence stress distribution around the implant and the preservation of surrounding bone. This study used three-dimensional finite element analysis (FEA) to assess the combined effects of these factors. Two implants with abutment heights of 3 mm and 6 mm were modeled and placed in mandibular bone blocks representing class II and class IV bone, according to Lekholm and Zarb’s classification. A static load of 150 N, inclined at 6° buccolingually, was applied during the analysis. The simulation results showed that increasing the abutment height raises stress on the implant, leading to greater stress transfer to the peri-implant bone. The von Mises stress levels were higher in the crestal cortical bone of the class IV model with a 6 mm abutment (126 MPa). Notably, peak stresses exceeding 300 MPa were localized at the implant-abutment connection. These findings suggest that abutment height is a critical factor that negatively affects the biomechanical response, especially in low-density bone, although longer abutments offer biological benefits. This highlights the importance of minimizing the crown-to-implant ratio to reduce overload, preserve bone, and prevent mechanical failure complications. 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

Polyetheretherketone (PEEK) has emerged as a revolutionary material in modern dentistry because of its unique combination of mechanical strength, biocompatibility, and versatility. This literature review examines the current applications and future potential of PEEK in various dental disciplines. PEEK’s favorable properties, including its low specific weight, high strength-to-weight ratio, and ability to be easily machined, have led to its adoption in prosthetics, implantology, and dental esthetic restorations. This material has shown promise for fabricating crowns, bridges, removable partial denture frameworks, and implant components. PEEK’s radiolucency and bone-like elastic modulus make it particularly suitable for dental implants and abutments. Additionally, its resistance to degradation and compatibility with various surface treatments enhances its long-term performance in the oral environment. While challenges such as bonding to other dental materials and aesthetic limitations exist, ongoing research is addressing these issues through surface modifications and composite formulations. As the dental field continues to evolve, PEEK’s adaptability and biocompatibility position it a key player in the development of next-generation dental materials and techniques, potentially transforming patient care and treatment outcomes in dentistry. Full article

Background/Objectives: Recent research has indicated that placing dental implants in patients diagnosed with bruxism has led to higher rates of implant failure. This study aimed to provide more accurate knowledge about the relationship between bruxism and implant loss in patients (number, age, gender) with different numbers of implants and prosthetic restorations, considering the follow-up time, compared to non-bruxers. Methods: A systematic search was conducted in PubMed and Cochrane Library using the keyword combination “dental implant”, “bruxism”, and “implant failure”. This search had no language or time restrictions. Results: The review included 15 papers, which were divided into four groups. The first group focused on studies regarding implant loss regardless of the superstructure. In the second group, research on implant-supported removable prostheses was examined. The third group consisted of a single study specifically addressing implant-supported single crowns. Lastly, the fourth group comprised two studies investigating implant-supported single crowns and fixed partial dentures. Only three out of the fifteen studies failed to find a correlation between bruxism and implant failure. The meta-analysis shows a significant pooled effect across the included studies, with an odds ratio of 4.68. Conclusions: Bruxism is a probable risk factor for mechanical issues in implant-supported prostheses and implant-supported crowns. Additionally, elevated failure rates have been documented in patients with bruxism. Full article

This study aimed to assess clinical and radiographic outcomes, including implant survival, marginal bone loss, and patient satisfaction, in individuals with severe bone atrophy treated using a newly developed system of short and extra-short implants. A total of 44 implants (37 short and 7 extra-short) were placed with immediate loading in 11 patients. The patients were followed up at between 6 and 24 months. Bone changes, keratinized mucosa, bleeding on probing, probing depth, crown-to-implant ratio, and patient satisfaction were evaluated. An implant survival and success rate of 100% was observed. The peri-implant bone condition showed no significant associations between marginal bone loss (MBL) and gingival recession. In extra-short implants, the crown-to-implant ratio did not affect MBL in the evaluated times. However, short implants showed a statistically significant inverse correlation between mesial measurement and crown-to-implant ratio (p = 0.006) and between distal measurement and crown-to-implant ratio (p = 0.004) over six months. Plaque was present in the mesiobuccal regions in 38.64% of the implants, with extra-short implants having the highest relative frequency (71.4%). Bleeding was observed in 18.9% of the short implants in the mesiolingual region and 14.3% of the extra-short implants. There was a statistically significant association between bleeding on probing in the mesiobuccal region and the type of implant (p = 0.026). The analysis of probing depth showed no difference between the types of implants. Within the limits of this study, short and extra-short implants presented similar clinical and radiographic behavior of soft and hard tissues in the evaluated times. Full article

Objective: This study aimed to assess the impact of artificial intelligence (AI)-driven noise reduction algorithms on metal artifacts and image quality parameters in cone-beam computed tomography (CBCT) images of the oral cavity. Materials and Methods: This retrospective study included 70 patients, 61 of whom were analyzed after excluding those with severe motion artifacts. CBCT scans, performed using a Hyperion X9 PRO 13 × 10 CBCT machine, included images with dental implants, amalgam fillings, orthodontic appliances, root canal fillings, and crowns. Images were processed with the ClariCT.AI deep learning model (DLM) for noise reduction. Objective image quality was assessed using metrics such as the differentiation between voxel values (ΔVVs), the artifact index (AIx), and the contrast-to-noise ratio (CNR). Subjective assessments were performed by two experienced readers, who rated overall image quality and artifact intensity on predefined scales. Results: Compared with native images, DLM reconstructions significantly reduced the AIx and increased the CNR (p < 0.001), indicating improved image clarity and artifact reduction. Subjective assessments also favored DLM images, with higher ratings for overall image quality and lower artifact intensity (p < 0.001). However, the ΔVV values were similar between the native and DLM images, indicating that while the DLM reduced noise, it maintained the overall density distribution. Orthodontic appliances produced the most pronounced artifacts, while implants generated the least. Conclusions: AI-based noise reduction using ClariCT.AI significantly enhances CBCT image quality by reducing noise and metal artifacts, thereby improving diagnostic accuracy and treatment planning. Further research with larger, multicenter cohorts is recommended to validate these findings. Full article

Peri-implant infections, in the absence of adequate treatment, can finally lead to premature loss of the implant. Among targeted protocols recently proposed for the treatment of peri-implant bone defects, and in the case of short implants, reconstructive surgery represents a recommended option. The purpose of this study was to evaluate the outcomes, in terms of maintenance, of a reconstructive treatment for peri-implantitis in locking-taper plateau-design single-crown implants, followed for 5 years after surgery. A retrospective evaluation was conducted in 20 patients treated with access flap surgery, concomitant chemical and mechanical surface decontamination, and bone grafting (using a self-hardening mixture of bone substitutes and biphasic calcium sulfate without the use of membranes). Of the 21 implants assessed, 9 were 8 mm-length, and 12 were 6 mm-length. Implant loss and treatment success were, respectively, 0% and 80.95% after 5 years from surgery. All parameters related to bone levels and soft tissue conditions significantly improved after 3 years and remained stable at the 5-year follow-up. The proposed protocol, followed by an effective supporting periodontal therapy, demonstrated the maintenance of the function of all implants, providing adequate stability during the healing process after surgery and limiting the onset of disease recurrence. Full article

The aim of this present record-based retrospective study was to investigate the influence of the crown-implant ratio (CIR) and implant inclination in relation to the occlusal plane on the marginal bone loss (MBL) around dental implants supporting single crowns in the posterior region of the jaws. All the cases of implant-supported single crowns in the premolar and molar regions were initially considered for inclusion. Only implants not lost, with baseline radiographs taken within 12 months after implant placement and with a minimum of 36 months of radiological follow-up, were considered for the analysis of MBL. Univariate linear regression models were used to compare MBL over time between 12 clinical covariates, after which a linear mixed-effects model was built. After the exclusion of 49 cases, a total of 316 implant-supported single crowns in 234 patients were included. The results from the statistical models suggested that implant inclination and anatomical- and clinical CIR (the main related factors investigated in the study) were not statistically significantly related to MBL over time. Age (older people), tooth region (premolar), and bruxism (bruxers) had a statistically significant influence on MBL over time. Full article

Dental implants provide a good solution for the replacement of tooth roots. However, the full restoration of tooth functions relies on the bone-healing period before positioning the abutment and the crown on the implant, with the associated risk of post-operative infection. This study aimed at developing a homogeneous and adherent thin calcium phosphate antibacterial coating on titanium dental implants by electrodeposition to favor both implant osseointegration and to limit peri-implantitis. By combining global (XRD, FTIR-ATR, elemental titration) and local (SEM, Raman spectroscopy on the coating surface and thickness) characterization techniques, we determined the effect of electrodeposition time on the characteristics and phases content of the coating and the associated mechanism of its formation. The 1-min-electrodeposited CaP coating (thickness: 2 ± 1 μm) was mainly composed of nano-needles of octacalcium phosphate. We demonstrated its mechanical stability after screwing and unscrewing the dental implant in an artificial jawbone. Then, we showed that we can reach a high copper incorporation rate (up to a 27% Cu/(Cu+Ca) molar ratio) in this CaP coating by using an ionic exchange post-treatment with copper nitrate solution at different concentrations. The biological properties (antibiofilm activity and cytotoxicity) were tested in vitro using a model of mixed bacteria biofilm mimicking peri-implantitis and the EN 10993-5 standard (direct contact), respectively. An efficient copper-doping dose was determined, providing an antibiofilm property to the coating without cytotoxic side effects. By combining the electrodeposition and copper ionic exchange processes, we can develop an antibiofilm calcium phosphate coating on dental implants with a tunable thickness and phases content. Full article

This study aimed to find the optimum mechanical characteristics of the restorative materials for the manufacture of implant crowns subjected to impact loading when different combinations of materials are used for the inner and outer crown. Several combinations of external–internal crown restorative materials were analyzed. The dynamic stresses at eight different zones of a dental implant subjected to an impact load and the influence of several mechanical properties, such as the Young’s modulus, Poisson’s ratio, density, and initial velocity, were analyzed and compared. A detailed 3D model was created, including the crown, the retention screw, the implant, and a mandible section. The model was then built by importing the 3D geometries from CAD software. The whole 3D model was carefully created in order to guarantee a finite element mesh that produced results adjusted to physical reality. Then, we conducted a numerical simulation using the finite element method (FEM). The results of the FEM analysis allowed for evaluating the effect that different combinations of restorative materials and mechanical properties had on the stress distribution in various regions of the implant. The choice of restorative material is a factor to be considered in order to preserve the integrity of osseointegration. Restorative materials transfer more or less stress to the dental implant and surrounding bone, depending on their stiffness. Therefore, an inadequate Young’s modulus of the rehabilitation material can affect the survival of the implant over time. Eight interactive graphics were provided on a web-based surface platform to help clinical dentists, researchers, and manufacturers to select the best restorative materials combination for the crown. Full article

Background: The purpose of this study was to measure and compare the strain levels in the peri-implant bone as generated by the blade-like implant (BLI) and the screw-type implant (STI) with two different internal connections (hexagonal and conical) and with a 1:1 and 2:1 crown/implant (C/I) ratio. Methods: The implants (BLI and STI) were placed into sawbones according to the manufacturer’s protocol. Two strain gauges, horizontal and vertical to the implant axis, were placed around each implant on the bone surface 1 mm from the cervical part. Each implant was loaded by a material testing machine at a force of 100 N. Micro-strains (με) generated in the surrounding bone were measured by a strain gauge and recorded. Results: Recorded micro-strains were not significant in both the insertion and loading phases (p < 0.0625). The average recorded micro-strain values were lower in the horizontal dimension of STI with hexagonal connection when the C/I ratio was 2:1 compared with BLI, 210 με and 443 με, respectively. Conclusion: Within the limitations of this study, implant design, implant-abutment connection and C/I ratio did not influence strain values in bone and there is no statistically significant effect of these parameters on bone. Full article