Prosthetic Abutments Research Articles

Prosthodontic rehabilitation with all-on-four implant treatment combined CAD/CAM prosthesis in an oral cancer patient: a case report

BackgroundThe microvascular free fibula (MFF) flap is a reliable treatment modality for mandibular reconstruction and is suitable for dental implant placement after oncologic surgery. The most common issue with the MFF flap is its limited bone height, which typically results in excessive interarch space and complicates prosthodontic therapy. Overcoming the physical limitations from tumor excision and reducing the treatment time for prosthodontic rehabilitation to improve quality of life are critical clinical challenges.Case PresentationA 64-year-old male with lower left gum and bilateral buccal cancer received a single-layer microvascular MFF flap to reconstruct a mandibular defect post-tumor excision. He underwent a bilateral modiolus Z-plasty combined with a skin flap debulking procedure to relieve oral contracture, achieving adequate mouth opening for prosthodontic rehabilitation. Scar tissue bands on the bilateral cheeks significantly affected retention and stability, hampering dental impression performance. The patient sought prosthodontic rehabilitation to enhance his chewing function and quality of life promptly. Prosthodontic rehabilitation with all-on-4 implant therapy, utilizing computer-aided design and computer-assisted manufacturing (CAD/CAM), was completed within one month.ConclusionThis case utilized the all-on-4 implant system to address the insufficient fibular height for conventional dental implant placements. Dental CAD/CAM was employed to mill custom prosthetic abutments and a large titanium framework for the implant bar overdenture, compensating for the excessive interarch space between the grafted fibula and maxilla. This treatment approach successfully shortened the prosthodontic rehabilitation time and overcame anatomical limitations.

Impact of Diamond-like Carbon Films on Reverse Torque: Superior Performance in Implant Abutments with Internal Conical Connections

The loosening or fracture of the prosthetic abutment screw is the most frequently reported complication in implant dentistry. Thin diamond-like carbon (DLC) films offer a low friction coefficient and high wear resistance, functioning as a solid lubricant to prevent the weakening of the implant–abutment system. This study evaluated the effects of DLC nanofilms on the reverse torque of prosthetic abutments after simulated chewing. Abutments with 8° and 11° taper connections, with and without DLC or silver-doped DLC coatings, were tested. The films were deposited through the plasma enhanced chemical vapor deposition process. After two million cycles of mechanical loading, reverse torque was measured. Analyses with scanning electron microscopy were conducted on three samples of each group before and after mechanical cycling to verify the adaptation of the abutments. Tribology, Raman and energy-dispersive spectroscopy analyses were performed. All groups showed a reduction in insertion torque, except the DLC-coated 8° abutments, which demonstrated increased reverse torque. The 11° taper groups experienced the most torque loss. The nanofilm had no significant effect on maintaining insertion torque, except for the DLC8 group, which showed improved performance.

A novel digital way to measure the vertical and horizontal dimensions of the supra-crestal peri-implant soft tissues.

To report on a novel digital superimposition workflow that enables measuring the supra-crestal peri-implant soft tissue dimensions all along implant treatment and afterwards. A preoperative CBCT and intra-oral scans (IOS) are successively taken before surgery, at the end of the healing period, at prosthesis delivery, and over time; they are digitally superposed on a dedicated software. Then, the stereolithography files (STL) of the healing abutment, of the prosthetic abutment and the crown are successively merged into the superposition set of IOSs. The workflow protocol of merging successively the STL of each item into the superposition set of IOSs enables capturing the dimensions of the height and width of the supra-crestal soft tissues, at every level of the healing abutment, the prosthetic abutment and the crown. In addition, it allows measuring the vertical distance that the crown exerts pressure on the gingiva and the thickness of the papillae at every level of the abutment. This novel digital superimposition workflow provides a straightforward method of measuring the vertical and horizontal dimensions of the supra-crestal peri-implant soft tissues, including the papillae, at each stage of the implant treatment process. It allows investigating a certain number of soft tissue variables that were previously inaccessible to clinical research. It should help enhancing our comprehension of the peri-implant soft tissue dynamics.

Prospective observational cohort study of the change of the marginal bone crest in relation to the prosthetic abutment height and the peri-implant vertical mucosal thickness at implants positioned subcrestally.

To evaluate the influence on peri-implant crestal bone loss exerted by the vertical mucosal thickness and the abutment height over 12 months after placement of the restoration on subcrestal implants with change of platform, using a restoration abutment platform smaller than the implant platform. A total of 99 implants were rehabilitated in the maxillary and mandibular posterior regions. A total of 22 implants were rehabilitated in the maxilla and 77 implants in the mandible, using digitally designed customized abutments with Atlantis weborder software, from the commercial house Dentsply Sirona (Dentsply Sirona S.A., Barcelona, Spain), version 4.6.5, adapting the height to the vertical thickness of the mucosa. Clinical and radiographic monitoring begins during the surgical procedure of placement of the implant and ends 12 months afterwards. Crestal bone loss was evaluated through the Carestream® CS8100 3D radiographic equipment. In all cases, the greatest loss of marginal bone occurred between the day of surgery (Tx) and placement of the rehabilitation (To). The average bone loss between both times was greater when the abutment height and vertical mucosal thickness did not exceed 3 mm. Subsequently, bone loss slowed and stabilized at 12 months. The minimum abutment height and the vertical mucosal thickness are factors to take into account when minimizing peri-implant marginal bone loss, the abutment height having the greatest importance according to the clinical data obtained.

Influence of Abutments Surface (machined vs. laser-microgrooved) in Soft-tissue Response During One Year of Function: Clinical and Biochemical Outcomes of a RCT with Split-Mouth Design

The purpose of this study was to evaluate peri-implant soft tissue response by assessing IL-6, IL-1b and MMP-8 levels in peri-implant crevicular fluid (PICF) around machined vs. laser-microgrooved implants/healing/prosthetic abutments during 1 year of function. Twenty-four patients each received 2 one-stage implants in a split mouth design on the same jaw. In each patient, one implant, one immediate healing, and one prosthetic abutment with a machined surface (M group), and one implant, one immediate healing abutment and one prosthetic abutment with a laser-microgrooved surface (LMS group) were used. PICF sampling, pocket probing depths (PPD) and bleeding on probing (BOP) were assessed at 1, 3, and 12 months. IL-6, IL-1b and MMP-8 levels were determined by specific enzyme-linked immunosorbent assay systems (ELISA). Repeated measure ANOVA was used to run comparisons with groups and between groups months at 1, 3, and 12 months. At 3 and 12 months, the LMS group showed significantly lower PD, BOP and IL-6, IL-1β and MMP-8 levels than the M group (P<.05). This study suggests the presence of more remodeling and/or inflammatory phenomena around implants/abutments with a machined surface than around implants/abutments with a laser-microgrooved surface.

The Use of a New Safe Angle Concept for Immediate Implant Placement in the Anterior Maxilla: A Cross-Sectional CBCT Study

To introduce a new method for labiopalatal positioning and angulation of immediately placed dental implants in the anterior maxilla with relation to the type of abutment used (straight/angled abutment). CBCT scans from the database of a private practice were searched for patients who received immediate implants in the anterior maxilla. After superimposition of the initial and postoperative scans, the incisor root angle (IRA), incisor implant angle (IIA), and the difference between these angles were measured. An assessment was then made about whether the implant position would be within the safe angle or not. Age, sex, tooth/implant site, and type of prosthetic abutment (straight/angled) were retrieved from the patients' records. A total of 74 patients with 95 immediate implants altogether were selected for analysis. In regard to the type of abutment, 76 (80%) were straight, and 19 abutments (20%) were angled. Regardless of abutment type, 72 implants (75.8%) were placed within the safe angle, while 23 implants (24.2%) were placed outside it. All 19 implants with angled abutments were placed outside the safe angle. There were statistically significant associations between placement within the safe angle and type of abutment (P < .001; OR = 19), IRA (P < .001; effect size = 0.904), difference between IIA and IRA (P < .001; effect size = 1.209), and sex (P < .001; OR = 2.995). There was no statistically significant association between placement within the safe angle and IIA (P = .757, effect size = 0.063), site (P = .200; effect size = 0.184 ), or age (P = .387; effect size = 0.208). There was a statistically significant association between the type of abutment and the IRA (P = .001; effect size = 0.762) as well as the difference between IIA and IRA (P < .001; effect size = 1.056). The safe angle concept can be used as a reliable planning tool to determine the correct implant positioning for immediate implant placement in the anterior maxilla. Applying the safe angle concept will reduce the need for angled abutments for prosthetic correction.

Survival Rate of Implants and Mechanical Complications of 64 Implant-Supported Complete Arch Prostheses in Maxillary Edentulous Patients with a Follow-Up of up to 12 years: A Cross Sectional Analytical Study.

This study aimed to identify the technical complications associated with maxillary complete-arch implant-supported fixed prostheses (ISFPs) and to evaluate the survival rates of both implants and prostheses. Additionally, we sought to analyze the impact of the presence of cantilevers, the type of prosthetic abutment, and the number of implants on the occurrence of complications. Data were obtained from standardized clinical assessments carried out in a single appointment by two calibrated professionals using information from dental records. The sample consisted of 64 patients rehabilitated with ISFPs classified as hybrid prostheses (metal-resin). The survival rate for implants was 98.6% after 1 to 12 years (5.2 years ± 36.6 months) and was 100% for the prostheses after a follow-up period of 12 to 144 months (mean 48.1 ± 33.94 months). The most frequent complications were occlusal wear (82.8% of patients) and loosening of prosthetic screws (16.6%) and abutments (8.1%). Screw loosening frequency was significantly greater in 30-degree abutments compared with straight abutments (P=0.008), but no significant difference was found between 17-degree and 30-degree abutments. Prostheses with a higher occurrence of screw loosening had a greater average CL/AP spread ratios (0.9 􀀀 0.5). In addition, abutments installed on distal implants were more likely to loosen (P<0.001). The absence of mutually protected occlusion did not significantly influence the loosening of screws and prosthetic abutments. Implantsupported fixed maxillary complete-arch rehabilitations have high survival rates but are subject to technical complications.

Quantification and Influence of IL-1β on Pain and Inflammatory Response after Placement of a Cement-Screw-Retained Restoration.

Background: The objective of this study was to evaluate the pain and inflammatory response in soft tissues using healing and prosthetic abutments of different diameters and lengths. Methods: The study population was rehabilitated with Astra Tech EV single implants (Dentsply Sirona, Atlantis, Dentsply Sirona S.A., Barcelona, Spain) of 4.2 and 4.8 millimetres in diameter in the upper and lower maxilla and loaded with custom abutments digitally designed using Dentsply Sirona's Virtual Atlantis Design software (Atlantis WebOrder, Dentsply Sirona S.A., Barcelona, Spain), version 4.6.5. The custom abutments had a larger diameter than the healing abutments to evaluate for biomarkers through ELISA. Results: Rehabilitations in the mandible and with healing abutments with diameters less than 4.29 mm and rehabilitators with diameters less than 2.18 mm elicited a higher pain and inflammatory response and, in turn, higher interleukin-1β values. Conclusions: Greater inflammation was evident in cases in which healing abutments with reduced diameter were used compared to the same subsequent rehabilitation with prosthetic abutments with larger diameters.

The Impact of Different Implant Approaches in Overdenture Rehabilitated Diabetic Patients: A Two-Year Follow-Up

Diabetes Mellitus (DM) is identified as an important condition that leads to implant complications, and the apico-coronal position and the prosthetic abutment seem to interfere with peri-implant tissue behavior This study aimed at assessing the effect on peri-implant parameters after implant loading of two different methodologies in type two diabetics patients (T2DM) who received implant muco-retained overdentures. Twenty-two mandibular edentulous T2DM received two implants: Test group: prosthetic abutment of a diameter smaller than the platform of the implant and a morse taper subcrestal implant level; Control group: prosthetic abutment of diameter identical to the platform and hexagonal external implant placed at crestal bone level. Clinical, inflammatory, and tomographic evaluations were performed at baseline (after prosthesis installation), and twelve and twenty-four months after implant loading. Test implants presented inferior probing depth and clinical attachment level compared to control at baseline and 12 months (p &lt; 0.05). Test implants presented reduced levels of pro-inflammatory cytokines at 24 months compared to the control implants (p &lt; 0.05). The control group had more changes in bone parameters from baseline to the first and second years (p &lt; 0.05). The test group resulted in reduced bone remodeling and better clinical conditions and positively modulated peri-implant immunoinflammatory molecules. Trial identification UTN code: U1111-1239-3638.

Italian School One Piece Implants Stabilized with Electrowelded Titanium Needle for The Rehabilitation in Aesthetic Area of Single Post-Extraction Edentulies with Immediate Loading

The stabilization of an one piece implant with an electrowelded titanium needle is a technique introduced at the end of the seventies of the last century to increase the primary stability, already acquired by means of the wide thread and bicorticalism, of the one-piece implants of the Italian school such as the Tramonte screw, especially in immediate loading rehabilitations of single edentulous upper front teeth and thus make the success of immediate loading predictable. The stabilization of a one piece implant is achieved by inserting a titanium needle (Scialom type) divergent from the axis of the main implant, a needle which must reach and impact the deep cortical bone and be welded with the intraoral welding machine to the one piece basic screw, to form a single prosthetic abutment. In addition to enhancing primary stability and increasing resistance to static and dynamic stress, given that by forming a single body with the implant it extends the support surface over a larger surface, needle stabilization also carries out an anti-rotational action, opposing the "unscrewing" effect that can be caused by the pressure exerted by the tongue during swallowing. Needle stabilization also helps to avoid those micromovements which, when they exceed 150 microns, can prevent the osseointegration process, leading to the failure of the immediate loading implant. Needle stabilization has proven to be particularly effective in the immediate loading of post-extraction single implants in the upper frontal sectors, with reduced bone depth, or with poorly mineralized bone.

Finite Element Analysis (FEA) for the Evaluation of Retention in a Conometric Connection for Implant and Prosthesis

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

Application of Graphene Oxide in Oral Surgery: A Systematic Review.

The current review aims to provide an overview of the most recent research in the last 10 years on the potentials of graphene in the dental surgery field, focusing on the potential of graphene oxide (GO) applied to implant surfaces and prosthetic abutment surfaces, as well as to the membranes and scaffolds used in Guided Bone Regeneration (GBR) procedures. "Graphene oxide" and "dental surgery" and "dentistry" were the search terms utilized on the databases Scopus, Web of Science, and Pubmed, with the Boolean operator "AND" and "OR". Reviewers worked in pairs to select studies based on specific inclusion and exclusion criteria. They included animal studies, clinical studies, or case reports, and in vitro and in vivo studies. However, they excluded systematic reviews, narrative reviews, and meta-analyses. Results: Of these 293 studies, 19 publications were included in this review. The field of graphene-based engineered nanomaterials in dentistry is expanding. Aside from its superior mechanical properties, electrical conductivity, and thermal stability, graphene and its derivatives may be functionalized with a variety of bioactive compounds, allowing them to be introduced into and improved upon various scaffolds used in regenerative dentistry. This review presents state-of-the-art graphene-based dental surgery applications. Even if further studies and investigations are still needed, the GO coating could improve clinical results in the examined dental surgery fields. Better osseointegration, as well as increased antibacterial and cytocompatible qualities, can benefit GO-coated implant surgery. On bacterially contaminated implant abutment surfaces, the CO coating may provide the optimum prospects for soft tissue sealing to occur. GBR proves to be a safe and stable material, improving both bone regeneration when using GO-enhanced graft materials as well as biocompatibility and mechanical properties of GO-incorporated membranes.

Clinical Efficacy Analysis of the Personalization of Prosthetic Abutments in Implant Supported Restorations in Comparison to Available Standard Titanium Abutments.

Personalized medicine has become an important direction to offer better solutions for health problems. In implantology, this trend was materialized through customizing dental abutments to each clinical situation. The demands for better esthetics and function of implant-supported restorations have imposed a more personalized variety of prosthetic abutments. This retrospective study compared clinical efficiency of personalized implant abutments with standard implant abutments in multiple implant restorations. Clinical data of patients who were admitted in a private clinic between 2011 and 2022 and received dental implant treatments were collected. All complications and undesired events from the patients' medical record charts were statistically analyzed. The implants were loaded using either standard or customized abutments. For complete arch rehabilitations with the SKY Fast & Fixed protocol, standard titanium prosthetic abutments were used. Our results suggest that the abutments choice for patients has moved throughout the years more towards the use of customized abutments. The number of customized abutments (414) was higher compared with the number of standard abutments (293). In our database, the most used abutments for the anterior area implants were made of titanium and zirconia, whereas for the posterior area, the preferred abutments were mostly titanium. The standard abutments were used almost entirely for immediate loading and implantation in both anterior and posterior areas (Fast & Fixed protocol). Complications were encountered mainly in restorations with standard abutments (9.22%) compared to customized abutments (2.7%), with titanium abutments being the most reliable, having only 1.79% complications.

In Vitro Characterization of an Anodized Surface of a Dental Implant Collar and Dental Abutment on Peri-Implant Cellular Response.

The purpose of this paper was to determine the effect of anodization on the in vitro proliferation and adhesion of immortalized human keratinocytes (HaCats) and mouse bone marrow-derived mesenchymal stem cells (BM-MSCs) in Titanium Grade 23 (Ti6Al4V ELI) discs and to describe the surface topography, roughness, and composition of dental implants (body and collar) and abutments submitted to an area-specific anodization process. HaCat cells and BM-MSCs were seeded onto discs with three different surface treatments: machined, area-specific anodization for abutments, and area-specific anodization for implant collars. Cell proliferation was assessed using a resazurin-based fluorescent dye on days 1, 3, and 7, while cell adhesion was examined using scanning electron microscopy (SEM). Surface topography, roughness, and composition were evaluated for six implant bodies with an anodized rough surface, six anodized implant smooth collars, and six anodized prosthetic abutments. Both HaCats and BM-MSCs showed increased viability over time (p < 0.001) with no statistically significant differences among the different surfaces (p = 0.447 HaCats and p = 0.631 BM-MSCs). SEM analysis revealed an enhanced presence and adhesion of HaCat cells on the anodized surface for the implant collars and an increased adhesion of BM-MSCs on both the anodized and machined surface abutments. The topography characteristics of the treated implants and abutments varied depending on the specific implant region. Chemical analysis confirmed the presence of oxygen, calcium, phosphorus, and sodium on the anodized surfaces. The area-specific anodization process can be utilized to create variable topography, increase the specific surface area, and introduce oxygen, calcium, phosphorus, and sodium to dental implants and abutments. While BM-MSCs and HaCat cells showed similar adhesion and proliferation on anodized and machined surfaces, a positive interaction between anodized Ti6Al4V ELI surfaces and these two cell lines present in the peri-implant mucosa was observed. Due to the limitations of the present study, further research is necessary to confirm these findings.

Mechanical Behavior of One-Piece and Two-Piece Tapered Prosthetic Abutments with 11.5 and 16 Degrees.

The objective of this study is to examine the mechanical behavior of two-piece abutments (Morse taper with 16° internal angulation and Morse taper with 11.5° internal angulation) before and after cyclic fatigue testing, following ISO 14801:2016 guidelines. The specimens were divided into three groups: a modified Morse taper with a taper angle of 16° (GM group), a conventional Morse taper (taper angle of 11.5° deg) with a two-piece (CMt group), and one-piece abutments (CMo group). Each experimental group was formed by ten implants and ten abutments (n = 10) for a total of 30 specimens (n = 30). The abutments were tightened and loosened, and a fatigue test was applied with 15 Hz and 5 × 106 cycles. Subsequently, the abutments were loosened, and a pull-out test was performed on the CMt group. Finite element analysis (FEA) was conducted on stress concentration regions. The statistical analysis of the loosening test was performed using two-way ANOVA and Tukey's tests (p < 0.05) to compare screw loosening within each group and between the groups with and without mechanical fatigue. Significant differences were found among the three groups in the loosening test when analyzing the values with and without fatigue (p < 0.001) within each group. When the groups were compared with each other, there was also a significant difference between them (p < 0.001), except between groups GM and CMt without fatigue (p = 0.840). In the pull-out test of the CMt group, the sample exhibited frictional locking only after fatigue (mean = 94.2 N). The FEA demonstrated a varied stress distribution in all groups. The stress was found to be more concentrated in the upper third and middle third regions of the implant, as well as in the opposite region of the load application for all three groups. Although the CMo group showed lower rates of loosening, it displayed a poorer stress distribution in comparison to the GM and CMt groups. On the other hand, the CMt group exhibited a satisfactory frictional lock after undergoing the fatigue tests.

Influence of Mechanical Cycling on Torque Values of Tapped-In and Screw-In Implant-Supported Crowns.

This study investigated the influence of mechanical cycling on screwed-in and tappedin implants restored with screw-retained metallic crowns. Three implant-abutmentcrown systems were evaluated: T1 (multi abutment) and T2 (standard abutment) received tapped-in abutments and S received a screwed-in abutment. The specimens were subjected to two million cycles of 0-150 N load, at 2 Hz, 30° inclination in a dry medium, and torque evaluation. Survival and removal torque were analyzed using chisquare, ANOVA, followed by Tukey's test. Differences between installation and removal torque were determined using a T-test for dependent samples. Analyses were performed in SPSS, considering α = 0.05. All specimens survived mechanical cycling in S, 40% in T1, 80% in T2 (p=0.008). Failures occurred due to loosening of the crown screw. A significant decrease in torque (p=0.000) was found. Group T1 had the lowest removal torque (1.6 ± 0.84 N.Cm²), followed by T2 (3 ± 1.49 N.Cm²) and S (6.3 ± 1.16 N. Cm²), and a statistical difference was found between Groups T1 and S. Both types of implantabutment connections were stable and can be considered for rehabilitative treatment, but failure and removal torque were influenced by the design of prosthetic abutment. Crowns were more susceptible to becoming loose in tapped-in systems.

Short implants: Influence of different diameters, torques, and transmucosal heights of straight prosthetic abutments on screw preload loss after cycling.

This study evaluated the influence of different implant diameters, insertion torques, and transmucosal heights on the loosening of abutments installed on short implants, after mechanical cycling. The Morse taper connection implants (n=96) tested were 5mm high, divided according to the platform diameter: 4 or 6mm. A universal abutment was coupled to each implant (with different transmucosal heights: 1 or 5mm). The sets were subdivided into 20- and 32-Ncm torque. After the cycle fatigue test, the detorque values were measured with a digital torque indicator. After mechanical cycling, the mean detorque values obtained for the abutment with 20-Ncm insertion torque were lower than for implants with 32-Ncm insertion torque, regardless of the platform diameter or transmucosal height. In the 20-Ncm torque group, there was no statistically significant difference in the detorque values between platform diameters or transmucosal heights. Otherwise, for 32-Ncm sets, a smaller platform diameter (4mm), and a longer transmucosal height (5mm) showed the lowest detorque values. In conclusion, implants placed with 32-Ncm insertion torque and abutments with 1mm transmucosal height and a 6mm implant diameter demonstrated the highest detorque values.

The influence of the prosthetic abutments colour in the aesthetics of the frontal teeth. A case report.

Abstract Introduction: Prosthetic restorations in the frontal teeth, in addition to functional and prophylactic requirements, must respond in a special way to aesthetic needs. This desideratum is a challenge, especially when the support for the future prosthetic parts is not characterized by a uniformity of color. This paper wants to highlight the importance of the color of prosthetic abutments, in the case of single restorations, for the frontal teeth. Case presentation: This manuscript presents the clinical case of a patient, with different prosthetic abutments, namely: a hybrid implant abutment - titanium and zirconium (lateral incisor - 1.2), nonvital natural teeth (central incisors – 1.1 and 2.1) and a vital natural tooth (lateral incisor – 2.2). Three single ceramic crowns on zirconium were confectioned, one with implant support and the other two on dental support, and a veneer for the vital lateral incisor. Conclusions: The prosthodontist must develop the best prosthetic solution for each individual case, together with the technician, so that the aesthetic results are not negatively influenced by the different colors of the existing prosthetic abutments.

Comparative Study of Dental Custom CAD-CAM Implant Abutments and Dental Implant Stock Abutments.

The implementation of CAD-CAM systems in dentistry has significantly influenced the evolution of dental implantology and implant-supported prosthetics within the past three decades. Implant-supported prostheses are comfortable and aesthetic. The prosthetic abutment has also faced a rapid design evolution, from the individualization of standard stock abutments offered by various manufacturers to a modern customization process using CAD-CAM technology. This paper presents a comparative study between 20 dental custom CAD-CAM implant abutments and 20 dental implant stock abutments, based on a set of measurements performed on the digital casts obtained from 24 cases of prosthetic rehabilitation on implants. The statistical analysis (Mann-Whitney U test) revealed significant differences between these two types of abutments: the incisal margin line diameter dimensions for custom abutments were significantly improved compared to standard abutments at the cervical level (U = 343.00, z = 3.868, p < 0.0005) and the incisal/occlusal level (U = 352.00, z = 4.112, p < 0.0005), while the inclination angle of the custom abutments relative to the 0-axis was significantly smaller than that of standard abutments (U = 115.50, z = -2.286, p = 0.022). The use of custom abutments leads to an increase in the final size of the abutment, an improvement in the retention of the prosthetic work, and reduces the angulation of the abutment in relation to the implant axis, thus decreasing the risk of unscrewing or fracturing the dental screw.

Comparative analysis of biomechanical response between zygomatic implant and Facco technique through the three-dimensional finite element method.

The placement of zygomatic implants is an alternative used for rehabilitation of edentulous patients with atrophic maxilla. However, the complexity of the various techniques suggested in the literature requires high skill from surgeons. Aim: The objective of this research was to compare the biomechanical performance of traditional technique of zygomatic implant placement in relation to a new proposal, the Facco technique, through finite element analysis. A three-dimensional geometric model of the maxilla was input into computer-aided design software (Rhinoceros version 4.0 SR8). STL file of the geometric models of implants and components supplied by the company Implacil De Bortoli was converted to volumetric solids through reverse engineering by RhinoResurf software (Rhinoceros version 4.0 SR8). Three groups were modeled: traditional technique, Facco technique without frictional contact and Facco technique with frictional contact, following the recommended position in each technique for implant placement. All models received a maxillary bar. Groups were exported to the computer-aided engineering software ANYSYS 19.2, in step format. Mechanical static structural analysis was requested with occlusal load of 120N. All elements were considered isotropic, homogeneous, and linearly elastic. Contacts were considered ideal and system fixation was considered at the bone tissue base. There is similarity between the techniques. Microdeformation values capable of generating undesirable bone resorption were not observed in both techniques. Highest values in the posterior region of Facco technique were computed at the angle of part B close to the posterior implant. Biomechanical behaviors of the two evaluated zygomatic implant techniques are similar. Prosthetic abutment (pilar Z) modifies the distribution of stresses over the zygomatic implant body. Highest stress peak was found in the pilar Z, but it is within acceptable physiological limits. Key words:Atrophic maxilla, zygomatic implants, surgical techniques, pilar Z, dental implants.