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Purpose: To examine the behavior and function of human gingival fibroblasts growing on healing abutments with or without laser-textured topography. Materials and Methods: Human primary gingival connective tissue fibroblasts were cultured on healing abutments with machined or laser-textured (Laser-Lok, BioHorizons) surfaces. Cellular and molecular responses were evaluated by a variety of tests, including cell density assay (WST-1), fluorescence microscopy, real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and detachment tests. Results: The machined surface showed monodirectional traces and scratches from milling, whereas the laser-textured surface showed a distinct morphology consisting of monodirectional mesoscale channels (15-µm pitch) and woven oblique microridges formed within the channels. There were no differences in initial fibroblast attachment, subsequent fibroblast proliferation, or collagen production between the machined and laser-textured surfaces. Fibroblasts growing on a laser-textured surface were found to spread in one direction along the mesochannels, while cells growing on machined surfaces tended to spread randomly. Fibroblasts on laser-textured surfaces were 1.8 times more resistant to detachment than those on machined surfaces. An adhesive glycoprotein (fibronectin) and transmembrane adhesion linker gene (integrin ß-1) were upregulated on laser-textured surfaces. Conclusions: The increased fibroblast retention, uniform growth, and increased transcription of cell adhesion proteins compellingly explain the enhanced tissue-level response to laser-created and hybrid-textured titanium surfaces. These results provide a cellular and molecular rationale for the tissue reaction to this unique surface; in addition, they support its extended use, from implants and healing abutments to diverse prosthetic components where enhanced soft tissue responses would be desirable. [ABSTRACT FROM AUTHOR]

Dental implants are crucial in contemporary oral rehabilitation, necessitating optimal integration with the surrounding soft tissues for durable success. The attachment between the implant surface and peri-implant mucosa should establish a secure seal to prevent bacterial infiltration and subsequent tissue inflammation. This concise review examines the histological and biological perspectives of peri-implant soft tissue reactions to zirconium and titanium abutments, shedding light on their respective advantages and limitations. While titanium has been the gold standard, zirconia has gained attention due to its biocompatibility and aesthetic appeal. Histological studies show comparable soft tissue attachment and inflammatory responses between the two materials. Further research is needed to explore surface treatments and optimize outcomes in dental implant rehabilitation. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to assess the vertical misfit at the implant-abutment interface in external and internal connections across various implant brands, comparing original milled titanium abutments with laser-sintered cobalt-chromium (Co-Cr) abutments. Materials and methods: A total of 160 implants from four different brands were utilized, with 80 featuring external connections (EC) and 80 internal connections (IC). Original milled titanium abutments (n = 160) and Co-Cr laser-sintered abutments (n = 160) were randomly attached to each connection type, following the manufacturer’s recommended torque. After undergoing thermal cycling, the vertical misfit was measured using a scanning electron microscope. Statistical analyses were performed using the Kruskal-Wallis and Mann-Whitney U tests. The significance level was set at α = 0.05. Results: The original milled titanium abutments exhibited the lowest misfit values. Significant differences were identified between both abutment types for EC (d = 109.578 μm; p = 0.0001) and IC (d = 44.317 μm; p = 0.002). The EC with laser-sintered abutments demonstrated the highest marginal misfit values, with an average of nearly 30 μm, while a misfit value of 11.382 μm was achieved in the IC. Differences were observed among the brands for milled abutments in both EC and IC. Similarly, variations were also noted for the laser-sintered Co-Cr abutments in EC and IC configurations. Conclusions: The vertical misfit of the original milled titanium abutments in all groups was within the clinically acceptable range for IC. The connection type significantly impacted the vertical misfit in laser-sintered Co-Cr abutments. Differences among the implant systems were observed for both connection types and abutment types evaluated. Clinical relevance: Using original milled titanium abutments, particularly in internal connection systems, can lead to better fit and stability at the implant-abutment interface, potentially reducing the risk of mechanical complications and improving long-term implant success. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Methods Results Conclusion Short implants are today a reliable, minimally invasive option for the rehabilitation of the posterior maxilla. However, maintaining marginal bone stability remains a crucial factor for long‐term success, particularly in the case of short implants. The present multicenter prospective case–control study aimed to compare the clinical outcomes of bone‐level and tissue‐level short implants in the posterior maxilla, focusing on implant survival and peri‐implant marginal bone stability over 1 year of function.Fifty‐nine patients who met specific inclusion criteria were enrolled and treated by three clinical centers with a total of 74 short implants, either bone‐level (7 mm in length, placed 1 mm sub‐crestally) or tissue‐level (5 or 6.5 mm in length). The primary outcome was physiological bone remodeling (PBR) measured via radiographs at baseline (T0), prosthesis delivery (T1), and 12 months post‐loading (T2). Statistical analysis was performed to evaluate differences in PBR between groups, with multivariate analysis assessing the influence of various patient and site‐specific factors.The final analysis included 58 patients who were treated with a total of 71 short implants, comprising 36 tissue‐level and 35 bone‐level implants (one patient dropped out as he did not attend follow‐up visits on time). All implants were rehabilitated with fixed, screwed prosthetics after 5 months, with no recorded complications up to 1 year of loading. Stability was similar between the two implant types at T0 and T1, with no significant differences in insertion torque and implant stability quotient (ISQ). Multivariate analysis revealed a significant positive correlation between insertion torque and ISQ at T0, as well as with bicortical engagement of the implant apex with the sinus floor. Tissue‐level implants demonstrated significantly lower peri‐implant bone remodeling (PBR) compared to bone‐level implants at both T1 (0.11 ± 0.27 mm vs. 0.34 ± 0.35 mm, p = 0.004) and T2 (0.30 ± 0.23 mm vs. 0.55 ± 0.42 mm, p = 0.003). Multivariate analysis showed a significant positive correlation between PBR (T0–T1) and thin vertical mucosal thickness (≤ 2 mm) at T0 in both tissue‐level and bone‐level implants. Additionally, PBR (T1–T2) in both groups significantly correlated with the use of short prosthetic abutments (≤ 2 mm) and, only in bone‐level implants, with crown emergence angles > 30°.Both tissue‐level and bone‐level short implants are effective options for implant‐supported rehabilitation in the posterior maxilla. Tissue‐level short implants offer superior marginal bone stability compared to bone‐level implants placed subcrestally, suggesting their favorable use in clinical practice. [ABSTRACT FROM AUTHOR]

Statement of Problem: Osseointegration is now primarily established, but soft tissue integration is still susceptible to failure and problematic on implant surfaces. So, implant dentistry is increasingly focusing on improving peri‐implant soft tissue integration. Purpose: The present study aimed to evaluate the blood fibrin clot formation and adhesion on the abutment after cleaning and decontamination and determine the suitable abutment surface associated with fibrin clot attachment. Materials and Methods: Forty‐two abutments (14 per group) were used in the present study: a brand‐new (BN), contaminated with biofilm (CO) and decontaminated with an enzymatic cleaner and autoclave sterilization (DEC). For a fibrin clot, 9 mL of whole human blood and abutments was centrifuged at 2700 rpm for 12 min. Clots were divided into two parts for histomorphometry and scanning electron microscopy (SEM) analysis. Twelve abutments disconnected from the clot and two not treated with blood were observed under SEM. Results: Residual debris and biofilm were observed on the abutment surface in the CO group but not in other groups. Healthy and organized fibrin clots formed on all abutments. The fibrin extension areas are distributed uniformly in BN and DEC groups but irregularly in CO. The surface percentage of the fibrin clot extensions was 41.76% ± 6.73, 26.99% ± 6.40, and 37.83% ± 9.72 for the BN, CON, and DEC groups, respectively. The blood clot‐attached areas in the CO group were statistically lower than the other groups. No difference was observed between the BN and DEC groups. Conclusions: This study confirmed that surface contamination could influence blood clot attachment on the abutment surfaces. Cleaning and sterilization can have a favorable effect on soft tissue healing on abutment surfaces. [ABSTRACT FROM AUTHOR]

During strong earthquakes, the footing of a rockable bridge can temporarily and partially separate from the support. This rocking motion can activate rigid‐like motions, reducing the deformation along the height of bridge piers and leading to smaller bending moments. As a result, rockable footing has been considered as a possibility for low‐damage seismic design of structures. For bridges, the seismic‐induced interaction between girders and adjacent abutments can change the structural dynamics due to the impeded girder movements. Although bridges with rockable footing, for example, the South Rangitikei viaduct, have been constructed, research on rockable bridges mainly focused on a single‐segment case. Physical experiments on rockable bridges considering pounding are very limited. In this work, large‐scale shake table experiments were performed on a two‐segment bridge model with abutments. The cases without pounding and with girder‐girder pounding alone were considered as references to help interpret the results. To investigate the consequence of footing rocking, the results of the rockable bridge on a rigid base were compared to that of the fixed‐base bridge. The study reveals that compared to a fixed‐base segment, the girder of a rockable segment is easier to move laterally. This change in dynamics due to rocking leads to less maximum pounding forces and thus reduces the damage potential to girders and abutments. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate hard and soft tissue response and mechanical integrity for screw-retained layered zirconia crowns bonded to titanium nitride-coated titanium (TiN) CAD/CAM abutments supported by implants at 1- and 2-year followups. Materials and Methods: A total of 46 patients were restored with a total of 102 free-standing implant-supported layered zirconia crowns, which were bonded to their respective abutments in the dental laboratory and delivered as a one-piece screw-retained crown. Baseline, 1-year, and 2-year data were collated on pocket probing depth, bleeding on probing, marginal bone levels, and mechanical complications. Results: Of the 46 patients, 4 patients with one implant each were not followed-up. These patients were not included in the analysis. Of the remaining 98 implants, due to failed appointments during the global pandemic, soft tissue measurements were recorded for 94 implants at year 1 and 86 implants at year 2, with a mean buccal/lingual pocket probing depth of 1.80/1.95 mm and 2.09/2.17 mm, respectively. Mean bleeding on probing was 0.50 and 0.53 at 1 and 2 years, which represents somewhere between no bleeding and a spot bleed according to the study protocol. Radiographic data were available for 74 implants at year 1 and 86 implants at year 2. The mean marginal bone change from baseline was +0.11 mm mesially and +0.19 mm distally at 1 year and +0.24 mm mesially and +0.16 mm distally at 2 years. The final bone level with respect to the reference point was +0.49 mm mesially and +0.19 mm distally at the end of the study period. Mechanical complications involving a slight misfit of the crown margin were recorded for one unit (1%), porcelain fracture for 16 units (16%), and a loss of preload for 12 units (12%) of < 5 Ncm (< 20% of initial preload). Conclusion: The biologic and mechanical stability of ceramic crowns bonded to CAD/CAM screw-retained abutments using angulated screw access was considered to be high, with overall bone gain, excellent soft tissue health, and only limited mechanical complications related to generally small fractures of the porcelain and a clinically insignificant loss of preload. [ABSTRACT FROM AUTHOR]

This study has been carried out to analyze the influence of the design of three geometric elements (wall thickness, platform width, and chamfer) of Ti-base abutments on the distribution of stresses and strains on the implant, the retention screw, the Ti base, and the bone. This study was carried out using FEA, analyzing eight different Ti-base models based on combinations of the geometric factors under study. The model was adapted to the standard Dynamic Loading Test For Endosseous Dental Implants. A force of 360 N with a direction of 30° was simulated and the maximum load values were calculated for each model, which are related to a result higher than the proportional elastic limit of the implant. The transferred stresses according to von Mises and microdeformations were measured for all the alloplastic elements and the simulated support bone, respectively. These results were validated with a static load test using a creep testing machine. The results show that the design factors involved with the most appropriate stress distribution are the chamfer, a thick wall, and a narrow platform. A greater thickness (0.4 mm) is also related to lower stress values according to von Mises at the level of the retaining screws. In general, the distributions of tension at the implants and microdeformation at the level of the cortical and trabecular bone are similar in all study models. The in vitro study on a Ti-base control model determined that the maximum load before the mechanical failure of the implant is 360 N, in accordance with the results obtained for all the Ti-base designs analyzed in the FEA. The results of this FEA study show that modifications to the Ti-base design influence the biomechanical behavior and, ultimately, the way in which tension is transferred to the entire prosthesis–implant–bone system. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to compare the microgap size between engaging (E) and non-engaging (NE) abutments and screw morphology changes between E and NE abutments using scanning electron microscopy (SEM) before and after cyclic loading (CL). Methods: Thirty-six implants were arranged into four groups as follows: Group 1, single units with E abutments; Group 2, single units with NE abutments; Group 3, three-unit fixed partial dentures with a hemi-engaging design; and Group 4, three-unit FPDs with two NE abutments. The microgap was evaluated using a stereomicroscope. SEM was used to qualitatively evaluate screw morphology. The specimens were subjected to axial loading first and then lateral loading (30°) using the settings; one million cycles (1.0 × 106 cycles) for each loading axis. Results: There were no significant differences detected in the microgap sizes between the E and NE abutment groups. In addition, there were no significant changes in the microgap sizes after CL in the E or NE abutment specimens. More damage to the screws was noticed after CL compared to before, with no difference in the patterns of damage detected between the E and NE abutments. Conclusions: No significant difference in microgap size was detected between the E and NE abutments. Furthermore, there was no significant difference in microgap size between the different prosthetic designs. From the SEM qualitative evaluation, there were similar screw morphology changes after CL between the E and NE abutments. [ABSTRACT FROM AUTHOR]

This review article investigates the properties and applications of polyetheretherketone (PEEK) in the field of dental implantology. PEEK has emerged as a significant material of interest due to its mechanical strength, biocompatibility, and radiolucency. The article provides a detailed examination of PEEK’s biocompatibility and the various reinforcements that enhance its performance, including PEEK/HA, PEEK/β-TCP–TiO2, and CFR-PEEK. Focusing on dental applications, we discuss PEEK’s use in implant abutments, fixed dental prostheses, implants, and its commercial forms available for dental use. Further, the mechanical behavior of PEEK and its composites is analyzed, including its elastic behavior under various stress conditions and wear resistance. Moreover, the article conducts an integrative systematic review on the stress distribution in dental implants or abutments made from reinforced PEEK composites, assessed through finite element analysis. The aim of this review is to provide insights into the current state of research, the benefits, challenges, and future prospects of PEEK in implantology, and the biomechanical evaluation methods that underpin the development of this promising material.

Estimating average vertical pillar stresses is a critical step in designing room-and-pillar mines. Several analytical methods can be used to estimate the vertical stresses acting on the pillars. However, the present analytical methods fail to adequately account for the influence of abutments on the distribution of vertical stresses, especially when applied to narrow panel widths and pillar layouts comprising evenly spaced barriers. In this study, a multi-layer perceptron neural network (MLPNN) was applied to predict the vertical loads of regular pillars more accurately. Hundreds of room-and-pillar mine layouts were modeled using a displacement discontinuity method (DDM), and a database of 2355 sampled pillar cases was compiled. The MLPNN was trained based on this database, and its prediction capabilities were further validated using simulations by a finite difference code (i.e., FLAC3D). The model predictions and the FLAC3D simulations reasonably agreed with a regression coefficient of 0.99. The model was also adapted for mine cases with evenly spaced barrier pillars, and its application to a real case study mine has shown to provide accurate pillar stress estimations; hence, this model is suitable for practical use at mines. Even though the MLPNN model cannot be applied universally to all mine situations, it seems as a significant improvement over existing analytical techniques in terms of accounting for the influence of abutments on pillar stresses.

Objective: To assess the peri‐implant soft tissue profiles between argon plasma treatment (PT) and non‐treated (NPT) healing abutments by comparing clinical and histological parameters 2 months following abutment placement. Materials and Methods: Thirty participants were randomly assigned to argon‐plasma treatment abutments group (PT) or non‐treated abutments (NPT) group. Two months after healing abutment placement, soft peri‐implant tissues and abutment were harvested, and histological and clinical parameters including plaque index, bleeding on probing, and keratinized mucosa diameter (KM) were assessed. Specialized stainings (hematoxylin–eosin and picrocirious red) coupled with immunohistochemistry (vimentin, collagen, and CK10) were performed to assess soft tissue inflammation and healing, and the collagen content keratinization. In addition to standard statistical methods, machine learning algorithms were applied for advanced soft tissue profiling between the test and control groups. Results: PT group showed lower plaque accumulation and inflammation grade (6.71% vs. 13.25%, respectively; p‐value 0.02), and more advanced connective tissue healing and integration compared to NPT (31.77% vs. 23.3%, respectively; p = 0.009). In the control group, more expressed keratinization was found compared to the PT group, showing significantly higher CK10 (>47.5%). No differences in KM were found between the groups. Significance: PT seems to be a promising protocol for guided peri‐implant soft tissue morphogenesis reducing plaque accumulation and inflammation, and stimulating collagen and soft tissue but without effects on epithelial tissues and keratinization. [ABSTRACT FROM AUTHOR]

The objective of the present retrospective multi-center study was to analyze the outcomes of bone-level (BL) implants and tissue-level (TL) implants in immediate-loading full-arch rehabilitations. Patients who were previously rehabilitated with full-arch immediate-loading rehabilitations with either BL or TL implants were considered. Data regarding implant survival rate, marginal bone loss (MBL), peri-implant probing depth (PPD), plaque index (PI), and bleeding on probing (BOP) were recorded, and the 1-year follow-up data were statistically analyzed between the two groups. In total, 38 patients were evaluated for a total implant number of 156 (n = 80 TL implants and n = 76 BL implants). An implant survival rate of 97.37% was recoded for the BL group while an implant survival rate of 100% was noted for the TL group. A total MBL of 1.324 ± 0.64 mm was recorded for BL implants, while a total MBL of 1.194 ± 0.30 mm was recorded for TL implants. A statistically significant difference was highlighted regarding MBL at the mesial aspect (p = 0.01552) of the implants, with BL implants presenting with higher MBL. Within the range of acceptable healthy values, a statistically significant difference was also highlighted regarding BOP (p < 0.00001), with TL implants presenting higher values. No statistically significant difference (p > 0.05) was recorded for any of the other variables analyzed. Within the limitations of the present retrospective study, both TL and BL implants seem to provide good clinical outcomes after a 12-month observational period when employed in immediate-loading full-arch rehabilitation. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the formed biofilm on two types of implant surfaces (hydrophilic or hydrophobic) associated with titanium (Ti) or zirconia (Zn) abutments. Materials and Methods: Samples were separated into four groups according to type of surface and abutment used (n = 10): (1) hydrophobic/Ti abutment, (2) hydrophilic/Ti abutment, (3) hydrophobic/Zn abutment, and (4) hydrophilic/Zn abutment. Implant-abutment assemblies were incubated with human saliva and supragingival biofilm. Samples of biofilm were evaluated by DNA Checkerboard hybridization, identifying up to 41 species. Scanning electron microscopy (SEM) images were obtained from the implants and abutments. Results: The microbial count was higher for samples from groups with the hydrophilic/Ti abutment, followed by hydrophobic/Zn abutment, hydrophilic/Ti abutment, and hydrophobic/Zn abutment (P < .05). Hydrophilic surfaces and Zn abutments showed the highest counts of microorganisms. Individual bacterial counts were variable between groups; the hydrophilic/Zn abutment group had the highest microbial diversity, including T forsythia, P nigrescens, S oralis, S sanguinis, L casei, M orale, P aeruginosa, P endodontalis, S aureus, S gallolyticus, S mutans, S parasanguinis, S pneumoniae, and C albicans. The hydrophilic/Ti abutment group had the highest count of T forsythia and T denticola, microorganisms of Socransky red complex. The SEM images showed the bacterial colonization in both surfaces of the implant and abutment. Conclusion: Different surfaces of implants and abutments showed significant differences in the count and diversity of species. The hydrophilic/Zn abutment group presented the highest count and diversity of target species. [ABSTRACT FROM AUTHOR]

Trans-mucosal platforms connecting the bone-anchored implants to the prosthetic teeth are essential for the success of oral rehabilitation in implant dentistry. This region promotes a challenging environment for the successfulness of dental components due to the transitional characteristics between soft and hard tissues, the presence of bacteria, and mechanical forces. This review explored the most current approaches to modify trans-mucosal components in terms of macro-design and surface properties. This critical review article revised intensely the literature until July 2023 to demonstrate, discuss, and summarize the current knowledge about marketable and innovative trans-mucosal components for dental implants. A large number of dental implant brands have promoted the development of several implant-abutment designs in the clinical market. The progress of abutment designs shows an optimistic reduction of bacteria colonization underlying the implant-abutment gap, although, not completely inhibited. Fundamental and preclinical studies have demonstrated promising outcomes for altered-surface properties targeting antibacterial properties and soft tissue sealing. Nanotopographies, biomimetic coatings, and antibiotic-release properties have been shown to be able to modulate, align, orient soft tissue cells, and induce a reduction in biofilm formation, suggesting superior abilities compared to the current trans-mucosal platforms available on the market. Future clinical implant-abutments show the possibility to reduce peri-implant diseases and fortify soft tissue interaction with the implant-substrate, defending the implant system from bacteria invasion. However, the absence of technologies translated to commercial stages reveals the need for findings to "bridge the gap" between scientific evidences published and applied science in the industry. [Display omitted] • Several designs for trans-mucosal platforms are exhibited on the commercial market. • Implant-abutment connectors should reduce/exclude the interface gap. • Nanotopographies, biomimetic coatings, and antibiotic-release properties have shown optimistic advances for trans-mucosal components. • Current research should aim to "bridge the gap" between fundamental evidence and marketable devices. [ABSTRACT FROM AUTHOR]

Over the past decade, emerging evidence indicates a strong relationship between prosthetic design and peri‐implant tissue health. The objective of this narrative review was to evaluate the evidence for the corresponding implant prosthodontic design factors on the risk to peri‐implant tissue health. One of the most important factors to achieve an acceptable implant restorative design is the ideal implant position. Malpositioned implants often result in a restorative emergence profile at the implant‐abutment junction that can restrict the access for patients to perform adequate oral hygiene. Inadequate cleansability and poor oral hygiene has been reported as a precipitating factors to induce the peri‐implant mucositis and peri‐implantitis and are influenced by restorative contours. The implant–abutment connection, restorative material selection and restoration design are also reported in the literature as having the potential to influence peri‐implant sort tissue health. [ABSTRACT FROM AUTHOR]

In many areas of restorative dentistry, metal-free materials offer an alternative to metal-based restorations while ensuring high levels of biocompatibility and esthetics. Rapidly evolving CAD/ CAM technology has significantly expanded the range of materials available, providing access to materials classes and their combinations not previously available within conventional manufacturing, such as zirconia ceramics and hybrid ceramics. In addition, digital methods offer previously unavailable options in diagnostics, greater planning reliability, better material quality through standardization of the manufacturing process, and reproducibility - significant benefits that can be used to advantage, especially in oral implantology. Even though technological progress in the field of metal-free materials has given rise to considerable improvements in their mechanical properties over the decades, their clinical long-term success is still very much dependent on an appropriate indication and proper material selection, on the knowledge and skills of the dental practitioner and dental technician, and on an adequate occlusion concept. The high rate of innovation - both with regard to the materials themselves and to CAD/CAM technology - therefore requires an adequate level of prior knowledge to sensibly and successfully implement the wide range of possibilities now open. It is becoming more and more puzzling for users to find their way around the many different new techniques and materials. This review article provides an up-to-date overview of the possibilities and limitations of metal-free implant-supported single-tooth restorations. This first part discusses abutments and cemented crowns. Resultant treatment concepts are presented and evaluated based on clinical examples. [ABSTRACT FROM AUTHOR]

Integral abutment bridges (IABs) are robust structures that avoid the use of bearings and expansion joints and are relatively maintenance-free compared to conventional bridges. The seismic design code of IABs is not fully developed, and the complex soil-abutment interaction is not well understood. Therefore, research was carried out at the Schofield centre, the University of Cambridge, to understand the backfill-abutment interaction under earthquake loading, aimed at developing design guidelines for the industry. Understanding the mechanics by which the foundation soil stiffness and strength govern the abutment deformation and, thus, the earth pressures generated behind the abutment is essential. Two centrifuge tests have been conducted simulating an abutment with the conventional abutment-deck connection (or semi-integral abutment bridge), where moment restraint is released. In this paper, the dynamic response of the abutment founded on dry and liquefiable sandy soil is compared. Different deformation modes have been observed depending on the relative abutmentsoil stiffness. The abutment experienced minimal base displacement in dry sands. Conversely, the abutment witnessed cyclic rotational ratcheting about the deck level in liquefiable soil. The dry soil test helped identify the zones where soil stiffness and strength loss can be critical. In the case of the saturated test, the water table level was up to one-third of the abutment height, fully saturating the foundation soil while the backfill height was dry. The comparative results highlight the vulnerability of semi-integral abutment walls to liquefaction-induced failure, as witnessed in the 2011 Christchurch earthquakes.

Purpose: To evaluate the biomechanical behavior between two different micro conical abutments: two-piece and one-piece abutments. Materials and Methods: Four groups were divided according to the prosthetic connection (internal or external hexagon) and abutment type. The vertical misfit between the abutment and implant was evaluated under stereomicroscope. Next, the implants were divided into pairs and embedded in polyurethane to receive two-element prostheses. The initial removal torque was measured for abutments and for prosthesis fixation. The samples were mechanically cycled (200 N, 2 Hz, 2 × 106 cycles) before measuring the torque loss in the same regions. For stress verification, a finite element analysis was used. Results: For vertical misfit, one-piece (4.70 ± 0.26 μm) < two-piece (16.8 ± 0.32 μm). For preload in abutment screw, two-piece = one-piece. For prosthetic screw, a higher percentage of preload was found for two-piece, but no statistical difference was observed after fatigue cycling between the groups. For stress analysis, no difference (10%) was observed for abutments, retention screw, or for the bone. Conclusion: The one-piece abutment maintained even amounts of preload after cyclic loading and presented less vertical misfit in comparison with the two-piece abutment for both implant connections. The use of one-piece abutments did not increase the stress and strain concentration, suggesting acceptable biomechanical behavior. [ABSTRACT FROM AUTHOR]

Introduction: Dental implant abutments play an important role in the health and aesthetics of soft and hard tissues around implants. Purpose: To compare mechanical properties and marginal fit of prefabricated and customized dental implant abutments and provide references to evaluate the relationship between abutment choice and clinical indications. Methods: Titanium abutments were randomly divided into prefabricated and customized abutments. Static and dynamic loads were applied according to ISO14801:2016. Mechanical properties, including fracture strength, fatigue strength, rotational torque value, and torque loss rate, were measured. The biological properties of the implant abutments were assessed using an internal marginal fit. The samples were sliced, and the internal marginal fit was examined using a scanning electron microscope before and after cyclic loading. The length of the tight contact was calculated at the level of the conical connection, lower internal connection, and screw threads. Microleakage was evaluated by immersing the samples in 1% methylene blue and measuring the absorbance. Results: The fracture strengths of the prefabricated abutments were greater than those of the customized abutments before and after cyclic loading. The average fatigue strengths of the prefabricated and customized abutments were 350 and 300 N, respectively. The removal torque loss of the customized abutments was significantly greater than that of the prefabricated abutments. Significant differences were found in conical connection before loading, while the screw threads showed substantial differences between the two groups after loading. Microleakage in the customized abutments was significantly higher than that in the prefabricated abutments before and after loading. Conclusions: Prefabricated abutments showed superior mechanical and biological properties compared with customized abutments in vitro, suggesting a greater risk of mechanical and biological complications occurring with the use of customized abutments. This study provides a reference for the clinical selection of implant abutments. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) has been introduced into implant dentistry as a viable alternative to current implant abutment materials. However, data on its physico-mechanical properties are still scarce. The present study sought to shed light on this topic utilizing an ex vivo chewing simulator model. A total of 48 titanium two-piece implants were allocated into three groups (n = 16 per group): (1) implants with PEEK abutments and an internal butt-joint connection (PBJ), (2) implants with PEEK abutments and an internal conical implant–abutment connection (PC), and (3) implants with zirconia abutments and an internal butt-joint connection (ZA). All abutments were restored with a non-precious metal alloy crown mimicking the upper right central incisor. A dynamic chewing simulation of half (n = 8) of the specimens per group was performed with 5 × 106 cycles and a load of 49 N at a frequency of 1.7 Hz with thermocycling between 5 and 55 °C. The other eight specimens served as unloaded controls. Surface roughness, implant–abutment connection microgaps (IACMs), and the titanium base–abutment interface microgaps (TAIMs) in the loaded groups were evaluated. Finally, a quasi-static loading test was performed in a universal testing machine with all samples to evaluate fracture resistance. Overall, 23 samples survived the artificial chewing process. One abutment screw fracture was observed in the PC group. The ZA group showed higher surface roughness values than PEEK abutments. Furthermore, ZA revealed lower TAIM values compared to PEEK abutments. Similarly, ZA was associated with lower IACM values compared to PBJ. Fracture loads/bending moments were 1018 N/704 N cm for PBJ, 966 N/676 N cm for PC, and 738 N/508 N cm for ZA, with no significant differences compared to the unloaded references. Artificial loading did not significantly affect fracture resistance of the examined materials. PEEK abutments were associated with better load-bearing properties than zirconia abutments, although they showed higher microgap values. PEEK abutments could, therefore, be feasible alternatives to zirconia abutments based on the present ex vivo findings resembling 20 years of clinical service. [ABSTRACT FROM AUTHOR]

The role of abutments on the seismic vulnerability of bridges has been relatively little studied in geotechnical literature. To cover this gap, 3D numerical simulations were herein performed, by studying the seismic performance of three single-span bridge configurations. The numerical models used OpenSees to account the effects due to soil structure interaction between the deck and the abutments. In particular, advanced materials were implemented to model the non-linear hysteresis and plasticity that are responsible for soil deformations and, thus, structural damage. A probabilistic-based approach was considered and analytical fragility curves were developed to account modeling uncertainties. The role of bridge deformability was investigated by considering several limit states based on the calculation of the longitudinal displacements of the deck. [ABSTRACT FROM AUTHOR]

Background: Dental implants are considered better, latest, and most advanced technique of teeth replacement in present times with more teeth loss and increased related concerns. Aims: The present clinical trial was carried out to assess marginal bone loss and implant failure in immediate and delayed loading implants. The study also evaluated healing using Polymerase Chain Reaction (PCR) and the effect of risk factors on marginal bone loss. Materials and Methods: The 44 subjects were randomly divided into two groups with immediate loading and delayed loading protocols. Various soft-tissue parameters were seen clinically. Quantitative PCR was done to detect biomarkers. The collected data were subjected to statistical evaluation with a level of significance at P < 0.05 and the results were formulated. Results: Concerning marginal bone loss, it was seen that for delayed loading, the bone loss at the implant level was 1.52 ± 0.14, 0.19 ± 0.11, and 0.40 ± 0.12, respectively, at placement, 1 and 2 years. Plaque and mucosal bleeding scores were low at the time of placement with respective values of 0.96 ± 0.12 and 28.42 ± 3.15 for the delayed loading group and 0.98 ± 0.11 and 30.24 ± 3.15 for the immediate loading group. Tartrate-resistant acid phosphatase (TRAP) showing remodeling was high at 3 months in delayed loading (13.3 ± 8.5). Alkaline Phosphatase (ALP) was highest in delayed loading at 3 months (25.2 ± 7.7) and immediate loading at 2 days (32.6 ± 13). Conclusion: Both immediate loading and delayed loading implants show similar results in terms of bone loss, soft-tissue parameters, and biomarkers in sulcular fluids with relatively few and manageable complications. [ABSTRACT FROM AUTHOR]

Recently, tissue-level implants with a convergent collar have been introduced. While different studies have investigated the outcomes of this implant design in the rehabilitation of single teeth, its use in full-arch rehabilitation has yet to be investigated. The present case report describes the clinical outcomes of a full-arch immediate loading rehabilitation using tissue-level implants, with and without using implant-abutment units, with 2 years of follow-up. A female patient with mandibular terminal dentition and a high level of bone resorption (distal areas with a few millimeters of residual bone in the vertical dimension and both distal and anterior areas with narrow crestal bone in the horizontal dimension) was seen at the C.I.R Dental School, Turin, Italy. The patient was seeking to be rehabilitated with fixed prosthodontics, and she was found eligible for an immediate loading implant full-arch rehabilitation. Four implants were inserted in the same appointment. The two anterior implants were inserted straight and connected directly to the prosthesis (no abutments); the two distal implants were tilted in order to avoid the alveolar nerve and connected to two 30° angulated abutments. Two years post-implant placement, all of the implants were successfully integrated, resulting in an implant survival rate of 100%. The peri-implant soft tissues were stable at all the implant sites. No differences were highlighted between those implants with and without abutments. Within the limitations of the present clinical report, implant full-arch rehabilitations with tissue-level implants both with and without implant-abutment units showed optimal outcomes after two years of follow-up. Further research is encouraged to confirm whether this implant design may be a valid alternative to traditional implants in this type of rehabilitation, with or without implant-abutment units. [ABSTRACT FROM AUTHOR]

Experimental results on scour at abutments under unsteady clear water flow condition are presented. Three shapes of short abutments (abutment length/upstream flow depth < 1) were tested, namely, rectangular/vertical wall, semi-circular, and trapezoidal/45° wing-wall abutments embedded in uniform sands of two sizes having d50 = 0.52 mm and 0.712 mm. The unsteadiness of the flow is considered in the form flood hydrographs of three forms, namely: advanced flood hydrograph (Type I), symmetrical flood hydrograph (Type II), and delayed flood hydrograph (Type III) with the flow maintained at clear water condition in all cases. The experimental findings are used to represent the influence of various parameters on scour depth at bridge abutments. It was observed that the scour depth at rectangular abutments is greater than that at trapezoidal and semi-circular abutments. The scour depths at abutments embedded in finer sediments are greater than those in coarser sediments. In addition, based on the study of effect of three flood hydrographs, it was noticed that the delayed flood hydrograph yields greater scour depth as compared to the other two cases. Further, based on the method of superposition and the correction of shape factor, a semi-empirical model using dimensionless parameters is proposed to compute the temporal evolution of scour depth at abutments under unsteady clear water conditions. The parameters used in this model include flow shallowness, flow intensity, sediment coarseness, and time factor. It was found that the proposed model corresponds well with the data of time-dependent scour depth in uniform sediments obtained from the present experiments (unsteady flows) and reported by different investigators (steady flows). [ABSTRACT FROM AUTHOR]

This article focuses on preclinical studies and reviews the available evidence from the literature on dental implant and abutment materials in the last decade. Specifically, different peri-implantitis materials and how surface modifications may affect the peri-implant soft-tissue seal and subsequently delay or hinder peri-implantitis are examined. This review analyzed more than 30 studies that were Randomized Controlled Trials (RCTs), Controlled Clinical Trials (CCTs), or prospective case series (CS) with at least six months of follow-up. Meta-analyses were performed to make a comparison between different implant materials (titanium vs. zirconia), including impact on bone changes, probing depth, plaque levels, and peri-implant mucosal inflammation, as well as how the properties of the implant material and surface modifications would affect the peri-implant soft-tissue seal and peri-implant health conditions. However, there was no clear evidence regarding whether titanium is better than other implant materials. Clinical evidence suggests no difference between different implant materials in peri-implant bone stability. The metal analysis offered a statistically significant advantage of zirconia implants over titanium regarding developing a favorable response to the alveolar bone. [ABSTRACT FROM AUTHOR]

Abstract Background Repeated removal and replacement of healing abutments result in frequent injuries to the soft tissues. Purpose The purpose of this study was to evaluate the effect of disconnection/reconnection of laser microgrooved vs. machined healing and prosthetic abutments on clinical periodontal parameters, marginal bone levels, and proinflammatory cytokine levels around dental implants. Material and methods Twenty-four patients each received 2 implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one healing and prosthetic abutments with a laser microgrooved surface (LMS group) and one healing and prosthetic abutments with machined surface (MS group) were used. Four months following implant placement (T0), the healing abutments were disconnnected and reconnected three times to carry out the impression procedures and metal framework try-in. Four weeks later (T1), definitive prosthetic abutments were installated with screw-retained crowns. Modified plaque index (mPI), modified gingival index (mGI) bleeding on probing (BOP), and probing depth (PD) were recorded at T0 and T1. At the same time points, samples for immunological analyses were taken from the sulcus around each implant. Peri-implant crevicular fluid (PICF) samples were analyzed for interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-α levels using the ELISA kit. Results At T0 and T1, mPI and mGI showed no statistical difference between the two groups, while higher PD and BoP values were noted for the MS group (P < 0.05). The mean PICF volume and mean concentrations of IL-1β, IL-6, and (TNF)-α in the LMS group were statistically less than those in the MS group (P < 0.05). In addition, comparison of IL-6 and IL-1β mean concentrations at T0 and T1 in the MS group showed a statistically significant increase (p < 0.05) over time, which was not noted for the LMS. Conclusion Disconnection/reconnection of healing and prosthetic abutments with a laser-microgrooved surface resulted in less inflammatory molecular response compared with conventional machined ones. Trial registration ClinicalTrials.gov NCT04415801 , registered 03/06/2020

Objective: To evaluate the frequency and severity of Non-carious cervical lesions (NCCLs) in patients reporting for provision of fixed dental prosthesis to the Department of Prosthodontics at Khyber College of Dentistry. Study Design: Descriptive Cross-sectional study. Setting: Department of Prosthodontics Khyber College of Dentistry, Peshawar. Period: March to September, 2019. Material & Methods: Patients of both genders above 18 years of age who reported to prosthetics department for provision of fixed dental prosthesis were included in this study. Frequency of Non-Carious Cervical Lesions was evaluated by visual and clinical examination. The severity levels of NCCLs were classified according to Smith-Knight tooth wear index (TWI) after assessment using William's probe and plain dental mirror. The data was analysed using SPSS version 21. Results: Participants ages ranged from 18 to 50 years with a mean age of 46 years ± 2.3 SD. Among the total 149 patients evaluated, 89 (59.7%) had Non-Carious Cervical Lesions. Of these, 52 (58.4%) respondents had level 2 severity. The presence of NCCLs lesion was not associated with the gender and different age groups. Conclusion: High frequency of non-carious cervical lesions were found among local population. Thorough investigations of etiological factors is required for the prevention and managements of these lesions. [ABSTRACT FROM AUTHOR]

• Dynamical loading on dental implants generates particle production and wear. • Large particles are trapped inside the internal connection. • Particle size is affected by implant and abutment material. • Stiffness of the complex is related to type of abutment material. • Low level ion release/leakage is seen during corrosion tests. Particle generation from implant components caused by frictional wear affect the surrounding peri-implant tissues. The objective of this study was to evaluate the effect of combining implant and abutment materials on wear and particle release in a dynamical loading setup. A customized dynamical loading machine was used to subject two implant materials (Titanium and Titanium- Zirconium alloy) paired with two different abutment materials (Titanium and Zirconia) to a cyclic loading set of 240.000 cycles (simulating 1 year of clinical use). The implant and abutment complex was immersed in corrosive liquid to collect particle debris and measure the release of corroded ions. Scanning electron microscopy was used to analyze signs of wear on the components after testing and evaluate the size and composition of particle debris. Wear signs were evident in all material couplings. Particle debris was found on top, inside the implants, and on the abutment heads. The particle size ranged between 0.6 and 16.9 µm, with larger particles composed of Ti. Smaller-sized particles were found in the container liquid ranging from 0.253 to 1.7 µm compared to inside the implants ranging from 3.25 to 95.3 µm. Larger particles were found inside Tizr implants compared to Ti implants. Low levels of ions released due to corrosion were found when measuring content in surrounding liquid. Particle generation is evident when subjecting dental implant and abutment couplings in a dynamic loading setup. Internally connected implants hinder the release of larger particles to surrounding container liquid. [ABSTRACT FROM AUTHOR]

Overdenture are removable prosthesis which may be implant supported or tooth supported. These prostheses have overcome the shortcomings of the conventional complete denture prosthesis by improving retention, support, masticatory load bearing capability etc. The present case report emphasized on the advantages of tooth supported overdenture using double cast metal copings. These prostheses if planned properly can help to reduce the residual ridge resorption rate as well as preserve the sensory perception. [ABSTRACT FROM AUTHOR]

Aim. To compare the efficiency of removable mini-implant retained dentures using different types of attachment.Materials and methods. The study included 51 edentulous patients. The patients were divided into three groups according to the attachment type and abutment shape: 1) ball-and-socket attachment, ball abutment (n = 26); 2) locator attachment, equator abutment, XiVE LOCATOR system (n = 14); 3) bar attachment (n = 11). Removable dentures were made of ordinary acrylic plastic. The placement of intraosseous dental implants with their sublingual engraftment was performed according to the traditional two-stage delayed-load procedure. The efficiency of implants was evaluated using the method of M.Z. Mirgazizov and the eponymous index. The dynamics of vertical bone resorption around implants was determined using dental panoramic radiography (6 months, 1 and 2 years after the treatment). A periotest was performed 6 months after the end of the orthopaedic treatment.Results. The one-year survival rate of implants reached 96.2% in group 1, amounting to 100% in groups 2 and 3. The two-year survival rate came to 92.3% in group 1, reaching 92.9% and 100% in groups 2 and 3, respectively. Inflammatory phenomena characteristic of peri-implantitis were noted one year after the implant placement in 7.7% (n = 2) of patients in group 1 and in 7.1% of patients in group 2, with no inflammatory phenomena being observed in group 3. Two years after the implant placement, peri-implantitis was observed in 19.2% and 21.4% of patients in groups 1 and 2, respectively, coming to 9.1% in group 3. The periotest revealed that six months after the placement, implant stability was higher in group 3 for both the lower and upper jaw (in comparison with groups 1 and 2), as evidenced by the shift in periotest values towards the negative part of the scale.Conclusion. The study revealed that bar attachment, as well as locator attachment (equator abutments), of removable dentures supported by mini implants is more efficient as compared to the ball-and-socket attachment.

Purpose: To evaluate the stress distribution, using 3‐dimensional finite element analysis (FEA), on different implant components of a mandibular screw‐retained fixed dental prosthesis (FDP) situation when using different combinations of engaging and nonengaging abutments. Material and Methods: A model of artificial bone was digitally designed. Dental implants were positioned in the lower right posterior area of teeth #'s 28 (premolar – pm) and 30 (molar – m). Restorative implant components were digitally designed and placed into the implant model. Four different implant abutment situations were simulated through FEA: (1) Both engaging abutments (mE‐pmE), (2) both nonengaging (mNE‐pmNE), (3) molar nonengaging and premolar engaging (mNE‐pmE), and (4) molar engaging and premolar nonengaging (mE‐pmNE). Thirty‐five (35) Ncm preload to the abutment screws and 160 N static load at 45° angle to the occlusal plane were applied in each group. Results: The equivalent Von Mises stress was measured on each component. Stress distribution changed among the different configurations and ranged from 516.0 to 1304.6 MPa in the implants, and from 554.6 to 994.5 MPa with the abutments. Higher stress was found for the mNE‐pmNE designs (1078.6‐1106.9 MPa). Engaging and nonengaging abutments had different stress distributions on the screw (698.8‐902.5 MPa). Peak stress areas were located on the upper part of the screws for the nonengaging configuration, and on the lower areas for the engaging abutments. The sum of the stress on both implants decreased in the following order: mNE‐pmNE > mE‐pmNE > mNE‐pmE > mE‐pmE. Conclusion: Under conditions of this study, abutment design produced different stress patterns to the implant components. The lowest and most balanced stress distribution was found for the mE‐pmE configuration followed by the mNE‐pmE configuration. [ABSTRACT FROM AUTHOR]

Objectives: The aim was to evaluate the rate of bone loss progression during experimentally induced peri-implantitis using two different implant-abutment connections in implants with identical surface topography. Material and methods: Forty-eight Regular Neck tissue-level SLA implants with a matching implant to abutment connection (TL) and 36 bone-level SLA implants with a switching platform implant to abutment connection (BL) were subjected to experimental peri-implantitis in two independent in vivo pre-clinical investigations. Experimental peri-implantitis was induced by means of silk ligatures during 3 months (induction phase), and followed for one extra month without ligatures (progression phase). Radiographic and clinical outcomes were evaluated longitudinally along both studies and subsequently compared between experiments. Results: During the induction phase, radiographic bone loss was significantly higher in implants with matched abutments compared with those with platform switching connections (2.65 ± 0.66 mm vs 0.84 ± 0.16 mm, respectively, p = 0.001). During the progression phase, both types of implant-abutment connection exhibited similar rates of radiographic bone loss. Similar outcomes were observed clinically. Conclusions: A platform switching connection resulted in a more benign development of peri-implantitis during the experimental induction phase of the disease. These differences, however, disappeared once the ligatures were removed (progression phase). Clinical relevance: Influence of the implant-abutment connection in peri-implantitis progression may be relevant when considering implant selection in the moment of placement. In this sense, platform switching abutment demonstrated less peri-implantitis development when compared to implant matching connection. [ABSTRACT FROM AUTHOR]

Recently, tissue-level implants with a convergent collar have been introduced. While different studies have investigated the outcomes of this implant design in the rehabilitation of single teeth, its use in full-arch rehabilitation has yet to be investigated. The present case report describes the clinical outcomes of a full-arch immediate loading rehabilitation using tissue-level implants, with and without using implant-abutment units, with 2 years of follow-up. A female patient with mandibular terminal dentition and a high level of bone resorption (distal areas with a few millimeters of residual bone in the vertical dimension and both distal and anterior areas with narrow crestal bone in the horizontal dimension) was seen at the C.I.R Dental School, Turin, Italy. The patient was seeking to be rehabilitated with fixed prosthodontics, and she was found eligible for an immediate loading implant full-arch rehabilitation. Four implants were inserted in the same appointment. The two anterior implants were inserted straight and connected directly to the prosthesis (no abutments); the two distal implants were tilted in order to avoid the alveolar nerve and connected to two 30° angulated abutments. Two years post-implant placement, all of the implants were successfully integrated, resulting in an implant survival rate of 100%. The peri-implant soft tissues were stable at all the implant sites. No differences were highlighted between those implants with and without abutments. Within the limitations of the present clinical report, implant full-arch rehabilitations with tissue-level implants both with and without implant-abutment units showed optimal outcomes after two years of follow-up. Further research is encouraged to confirm whether this implant design may be a valid alternative to traditional implants in this type of rehabilitation, with or without implant-abutment units.

Background: Repeated removal and replacement of healing abutments result in frequent injuries to the soft tissues. Purpose: The purpose of this study was to evaluate the effect of disconnection/reconnection of laser microgrooved vs. machined healing and prosthetic abutments on clinical periodontal parameters, marginal bone levels, and proinflammatory cytokine levels around dental implants. Material and methods: Twenty-four patients each received 2 implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one healing and prosthetic abutments with a laser microgrooved surface (LMS group) and one healing and prosthetic abutments with machined surface (MS group) were used. Four months following implant placement (T0), the healing abutments were disconnnected and reconnected three times to carry out the impression procedures and metal framework try-in. Four weeks later (T1), definitive prosthetic abutments were installated with screw-retained crowns. Modified plaque index (mPI), modified gingival index (mGI) bleeding on probing (BOP), and probing depth (PD) were recorded at T0 and T1. At the same time points, samples for immunological analyses were taken from the sulcus around each implant. Peri-implant crevicular fluid (PICF) samples were analyzed for interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-α levels using the ELISA kit. Results: At T0 and T1, mPI and mGI showed no statistical difference between the two groups, while higher PD and BoP values were noted for the MS group (P < 0.05). The mean PICF volume and mean concentrations of IL-1β, IL-6, and (TNF)-α in the LMS group were statistically less than those in the MS group (P < 0.05). In addition, comparison of IL-6 and IL-1β mean concentrations at T0 and T1 in the MS group showed a statistically significant increase (p < 0.05) over time, which was not noted for the LMS. Conclusion: Disconnection/reconnection of healing and prosthetic abutments with a laser-microgrooved surface resulted in less inflammatory molecular response compared with conventional machined ones. Trial registration: ClinicalTrials.govNCT04415801, registered 03/06/2020 [ABSTRACT FROM AUTHOR]

Background Restorative dentists frequently deal with the prosthesis coming loose after placing multiple crowns. The luting cement holds indirect restorations to the prepared tooth. However, the success of the restorations is impacted by mastication pressures and other undesired factors. Therefore, escape is required to increase the crown's life. Mechanical locking of the prepared tooth surface is one technique to address this issue, in addition to cement adherence, to extend the life of the restoration. Aims and objective The objective of the study was to evaluate the influence of surface roughness of prepared teeth on the retention of metal crowns. Methodology This in-vitro investigation was carried out on freshly extracted maxillary first premolars that were defect-free and had the same crown size. Using multiple grifts of varied coarseness, different surface roughness was created, allowing for the observation of an important factor like retention (black at 180-250 µm [micrometer], blue at 125-150 µm, green at 106-125 µm, red at 53-63 µm, yellow at 20-30 µm). Results IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. was used to perform the statistical analysis. Compounds were done before it began to guarantee that the study would have 80% power. There is a mean and a standard deviation for each quantitative variable. A one-way ANOVA was used for quantitative variables, and Tukey's post hoc analysis was conducted afterward. A probability value of less than 0.05 was used to determine statistical significance. According to the statistical findings, the prosthesis's retentive qualities improve as coarseness increases. Conclusion The resistance and retention form of the preparation is critical to the longevity of the prosthesis, based on the findings of the previously described study. Surface roughness, pins, slots, grooves, and other preparation modifications can enhance retention on the prepared tooth surface. The research findings indicate no need to polish the prepared tooth surface., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Ethics Committee for Research on Human Subjects of Sree Anjaneya Dental College issued approval N/A for human studies. Due permission was granted by the Institutional Ethics Committee for Research on Human Subjects of Sree Anjaneya Dental College to undertake this study. A reference number is not applicable for in vitro studies as it doesn't involve live human tissue or subjects. . Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Krishna K et al.)

Nocturnal parafunction is deleterious to the existing dentition and can create a unique dilemma when natural dentition opposes overdenture attachments. This situation can cause mutual destruction of the teeth and attachments, potentially making the attachments and prostheses unusable. This technique presents an innovative approach to protect overdenture attachments from the opposing natural dentition with a prosthesis that has less surface area coverage when compared to the daily prosthesis., (© 2024 by the American College of Prosthodontists.)

This article focuses on preclinical studies and reviews the available evidence from the literature on dental implant and abutment materials in the last decade. Specifically, different peri-implantitis materials and how surface modifications may affect the peri-implant soft-tissue seal and subsequently delay or hinder peri-implantitis are examined. This review analyzed more than 30 studies that were Randomized Controlled Trials (RCTs), Controlled Clinical Trials (CCTs), or prospective case series (CS) with at least six months of follow-up. Meta-analyses were performed to make a comparison between different implant materials (titanium vs. zirconia), including impact on bone changes, probing depth, plaque levels, and peri-implant mucosal inflammation, as well as how the properties of the implant material and surface modifications would affect the peri-implant soft-tissue seal and peri-implant health conditions. However, there was no clear evidence regarding whether titanium is better than other implant materials. Clinical evidence suggests no difference between different implant materials in peri-implant bone stability. The metal analysis offered a statistically significant advantage of zirconia implants over titanium regarding developing a favorable response to the alveolar bone.

Purpose: This study was conducted to analyze how a cleaning treatment using plasma of argon would affect fibroblast growth on titanium disks at different time points to determine whether this treatment could enhance soft tissue healing around titanium dental implant abutments. Materials and Methods: Sixty sterile disks made of machined grade 5 titanium were divided into two groups; 30 disks were left untreated (control) and 30 were cleaned using plasma of argon (test). To simulate clinical conditions during soft tissue healing around titanium abutments, both groups were immersed in a culture of murine fibroblasts (L929) for 2, 8, or 48 hours. After preparation, they were stained using 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) to label the cellular nuclei and fluorescent phalloidin to label the cellular bodies. The nuclei were counted, and cellular bodies were analyzed with fluorescent microscopy and imaging analysis software. Analysis was performed at the three different time points. Results: Fibroblast adhesion for the test group was statistically significantly greater versus the control group at 2 and 8 hours but not at 48 hours. At 2 and 8 hours, the cellular bodies in the test group appeared flatter and more spread out, revealing more advanced cellular adhesion, compared to the cells observed in the control group. At 48 hours, the test and control specimens were nearly indistinguishable. Conclusion: The removal of organic and inorganic contaminants from the surfaces of titanium disks using plasma of argon accelerated fibroblast adhesion in the early stages of colonization (2 to 8 hours). This effect disappeared after 48 hours as a result of saturation. Clinically, abutment cleaning using plasma of argon might positively affect soft tissue healing in early stages. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to examine the abutments in subjects requesting for fixed dental prosthesis (FDP) and to determine the frequency of compromised coronal conditions and their severity levels. Study Design: Descriptive, Cross-sectional Study. Setting: Department of Prosthodontics at Watim Dental Hospital, Rawalpindi. Period: August 2019 to March 2020. Material & Methods: Conducted on 163 subjects. Abutments were evaluated in terms of clinical crown length, crown inclination, caries and/or fracture, type and quality of restoration. Abutments were categorized on the basis of complexity of the procedure required to make the abutment usable for fixed dental prosthesis. Arch-wise distribution of the abutment with compromised conditions and their proportion was also calculated. Results: The mean age of the participants was 39.42 + 11.56 years with male to female ratio of with 2.2:1. Maximum number of the patients had edentulous spaces located in the mandibular posterior region. Tooth no. 46 displayed the highest frequency of use as abutment while tooth no. 18, 28,31,32,42 displayed the least frequency of use as FDP abutment. About half of the abutments (47%) had compromised restoration quality. On the basis of the degree of compromise, 41.1% of the abutments were usable without further treatment or required a simple corrective procedure, 45.4% required a relatively complex procedure to make them useable while 11% had sufficient compromise to preclude their use for FPD support. Only 2.5% of abutments were classified as adequate. Conclusion: About half of the studied abutments in subjects reporting for replacement of missing teeth with FDP were found to be compromised and a substantial proportion required complex restorative treatment/re-treatment prior to be used as FDP abutments. [ABSTRACT FROM AUTHOR]

Photobiomodulation (PBM) therapy is used to stimulate cell proliferation and metabolism, as well as reduce inflammatory cytokine synthesis, which plays a main role in the long-term stability of implants. This study assessed the response of gingival fibroblasts cultured on titanium (Ti) and zirconia (ZrO2), submitted to PBM and exposed to lipopolysaccharide (LPS). Cells seeded on Ti and ZrO2 were irradiated (InGaAsP; 780 nm, 25 mW) 3 times, using 0.5, 1.5, and 3.0 J/cm2 doses, and exposed to Escherichia coli LPS (1 μg/mL). After 24 h, cell viability (alamarBlue, n = 8), interleukin 6 (IL-6) and 8 (IL-8) synthesis (ELISA, n = 6), and IL-6 and vascular endothelial growth factor (VEGF) gene expression (qPCR, n = 5) were assessed and statistically analyzed (one-way ANOVA, α = 0.05). Cell morphology was evaluated by fluorescence microscopy. Increased cell viability occurred in all groups cultured on Ti compared with that of the control, except for cells exposed to LPS. Fibroblasts cultured on ZrO2 and LPS-exposed exhibited reduced viability. PBM at 3.0 J/cm2 and 1.5 J/cm2 downregulated the IL-6 synthesis by fibroblasts seeded on Ti and ZrO2, as well as IL-8 synthesis by cells seeded on ZrO2. Fibroblasts seeded on both surfaces and LPS-exposed showed increased IL-6 gene expression; however, this activity was downregulated when fibroblasts were irradiated at 3.0 J/cm2. Enhanced VEGF gene expression by cells seeded on Ti and laser-irradiated (3.0 J/cm2). Distinct patterns of cytoskeleton occurred in laser-irradiated cells exposed to LPS. Specific parameters of PBM can biomodulate the inflammatory response of fibroblasts seeded on Ti or ZrO2 and exposed to LPS. [ABSTRACT FROM AUTHOR]

Background: Soft tissue reaction to dental implant abutments influences the sustainability of restoration. Several abutment materials, such as titanium and gold alloy, have been introduced for strength and esthetic solutions. Zirconia and titanium‐base abutments have also become popular in recent years due to high esthetic demands. Purpose To investigate the immune cell infiltration into the soft tissue in response to different abutment materials. Materials and Methods: Twenty dental implants were placed in the posterior regions of 17 patients. Titanium, zirconia, gold alloy, and titanium‐base were randomly selected for each patient on the day of surgery. After 8 weeks of healing, the abutments were removed along with 1 mm of peri‐implant soft tissue. Immunohistochemical assessment was performed using labeled streptavidin‐biotin to identify T cells, B cells, macrophages, plasma cells, and microvascular infiltration. Results: Gold alloy demonstrated an overall higher inflammatory cell infiltration and highest number of CD3+, CD20+, and CD 68+ cells (P value <.05). The number of plasma cell and new microvascular infiltrations among abutment materials was not significantly different. Conclusion: Titanium, titanium‐base, and zirconia abutments showed comparable infiltration profiles; gold alloy abutments showed the highest B‐cell, T cell, and macrophage infiltration. None of the abutment materials caused clinical inflammation; hence, they can be effectively used. [ABSTRACT FROM AUTHOR]

• - Minimal focus is placed on IHAs, despite its vital role in soft tissue healing/shaping after dental implant body placement. • IHAs, which are designed and labeled for "single" use, are re-used in multiple patients as a common clinical practice. • Microbial analysis and surface characterization of IHA retrievals was performed after single and multiple implantations. • Streptococcus was the only genus present on every IHA, while Fusobacterium had the highest relative frequency across all IHAs. • IHA retrievals showed discoloration, abrasions, biological contamination, and higher corrosion rate as compared to controls. Very few studies have investigated dental implant components involved in the early stage of healing, especially the implant healing abutment (IHA), despite its vital role in soft tissue contouring and shaping after implant placement. Although these components are labelled by the manufacturer for "single-use only," it is a common clinical practice to clean, sterilize, and reuse them. In the present study, IHAs after single and multiple implantations were retrieved as per standard procedures, and biological material isolated from the surface was subjected to 16S rRNA sequence analysis. The microbiome analysis was followed by cleaning and sterilization in order to replicate clinical sterilization techniques. Following sterilization, retrievals were subjected to surface characterization with optical and scanning electron microscopy to investigate surface features, and electrochemical testing was performed to evaluate corrosion behavior. The microbiota was comprised of early colonizers including Streptococcus species and secondary anaerobic colonizers such as Fusobacterium , Capnocytophaga , and Prevotella species. The surface analysis revealed that irrespective of the cleaning and sterilization techniques, the pristine, homogeneous surface of the new, unused IHAs could not be restored. Both single and multiple-use IHAs had severe surface changes including discoloration, major abrasions, biological contamination, and the IHA retrievals exhibited higher corrosion rate as compared to control specimens. Reusing IHAs multiple times may not be a prudent practice as the microbial colonization and surface changes caused by using this component multiple times may affect the performance of IHAs in soft tissue healing. [ABSTRACT FROM AUTHOR]

Introduction: Replacement of missing teeth by a fixed dental prosthesis involves careful consideration of the biomechanical principles in designing the prosthesis. Treatment planning consists of determining a sequence of treatment logically designed to restore the patients' dentition to good health, with optimal function and esthetics. Aim: The aim of this study was to assess the knowledge and awareness of management of mesially tilted abutments. Materials and Methods: The study was conducted among 100 dental students in Tamil Nadu during the month of January 2019. A web-based questionnaire comprising 10 questions relating to awareness of management for mesially tilted abutments was formulated and circulated. The responses were then subjected to statistical analysis. The study protocol was reviewed and approved by the Institutional Ethical Committee of Saveetha Dental College and Hospitals, Chennai. Results and Conclusion: The study assessed that there is adequate knowledge on management of mesially tilted abutments among the students. The management of mesially tilted abutments can be further more better if we know the proper abutment selection methods. Thus, gaining an adequate knowledge would help us in the betterment of the outcomes. [ABSTRACT FROM AUTHOR]

Purpose: There are a variety of implant/abutment (I/A) junctions for the connection of implant-supported prostheses. The aim of this work was to compare the shear stress distribution in three types of I/A interfaces after application of oblique loading on the abutments, simulating loading on an anterior tooth. Materials and Methods: Similar wide unthreaded and cylindric implants (13.0 mm in length and 5.0 mm in diameter) and abutments were fabricated and embedded in photoelastic acrylic resin. The I/A assemblies featured three different I/A interfaces: external hex, internal hex, and internal taper. The samples were submitted to a compressive load of 0.6 kgf, which was applied to the abutment at an angle of 135 degrees. The maximum shear stresses were determined and observed at 21 points around the implants in the photoelastic models (n = 4). Graphics describing the maximum shear stress (y-axis) and the analyzed points (x-axis) were created, and the curve areas were calculated. The Kruskal-Wallis test was applied to analyze the results (P < .05). Results: There were no statistically significant differences between the groups (P = .058). Conclusion: All of the wide-diameter I/A junctions presented similar behavior under oblique loading and appeared to be suitable to support prostheses that could receive this type of loading. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the peri-implant stress fields generated from four different implant-abutment interfaces under axial loading applied at the center of the implant and several millimeters away from the implant center via photoelastic analysis. Materials and Methods: Similar unthreaded and cylindric implants and abutments were fabricated and embedded in photoelastic resin with four different implant-abutment interfaces: external hex, internal hex, internal taper (11.5 degrees), and solid connection to the abutment (one piece). The samples were submitted to vertical compressive loads; one was applied at the implant center (1.5 kg; centered load), and the other was applied 6.5 mm away from the center, 4.4 mm from the outside of the outer aspect of the implant (0.75 kg; off-centered load). The maximum shear stresses were determined and observed at 46 points around the implants under the centered load and at 61 points under the off-center load in the photoelastic models. Graphics describing the maximum shear stress (y-axis) and the analyzed points (x-axis) were obtained, and areas under the curves were calculated. Results: The centered loading (all points) resulted in small differences. The lowest amounts of stress were observed for the internal-taper implants, and values were minimally greater (0.4% to 3.3%) for the other implants. No statistically significant differences were found between groups for the centered load in any area. Under an off-center load, the internal-hex implants presented the least stress (all points). For off-center loading, the internal-hexagon implants differed significantly from the external-hex and one-piece implants and displayed the lowest stress levels. Conclusion: Under an off-center load, the internal-hex interfaces presented the lowest stress concentrations, internal-taper interfaces presented intermediate results, and one-piece and external-hex implants resulted in high stress levels. Centralized axial loads produced similar results. [ABSTRACT FROM AUTHOR]

Purpose: Misfit of implant components has been linked to restorative complications such as screw loosening. Although previous studies have shown a correlation between rotational misfit and screw loosening, the impact of casting procedures on rotational misfit is lacking. The aim of this in vitro study was to evaluate the effect of casting procedures on rotational misfit of cast abutments when compared to machined titanium abutments. Materials and Methods: Forty-eight external hexagonal implants and 48 abutments were placed in 4 groups of 12 samples each: (1) machined titanium abutments, (2) premachined palladium abutments cast-on with palladium, (3) plastic burnout abutments cast with nickel chromium, and (4) plastic burnout abutments cast with cobalt chromium. Rotational misfit between the external hexagon of the implant and the internal hexagon of the abutment was measured using standardized techniques and recorded in degrees. Mean values for each group were analyzed with analysis of variance and Tukey test. Results: The mean rotational misfit was 1.21 ± 0.57 degrees for machined titanium abutments, 1.77 ± 130 degrees for cast-on abutments, 1.98 ± 0.72 degrees for cast NiCr abutments, and 2.79 ± 1.13 degrees for cast CoCr abutments. Significantly greater rotational misfit was recorded with cast CoCr abutments when compared to machined titanium abutments (P < .05). Conclusion: Rotational misfit was less than 2 degrees for all groups except for cast CoCr abutments, which demonstrated a significantly greater rotational misfit. [ABSTRACT FROM AUTHOR]