Zirconia Abutments Research Articles

The effect of different abutment materials on peri-implant tissues-A systematic review and meta-analysis.

In patients with dental implants, what is the effect of transmucosal components made of materials other than titanium (alloys) compared to titanium (alloys) on the surrounding peri-implant tissues after at least 1 year? This systematic review included eligible randomized controlled trials identified through an electronic search (Medline, Embase and Web of Science) comparing alternative abutment materials versus titanium (alloy) abutments with a minimum follow-up of 1 year and including at least 10 patients/group. Primary outcomes were peri-implant marginal bone level (MBL) and probing depth (PD), these were evaluated based on meta-analyses. Abutment survival, biological and technical complications and aesthetic outcomes were the secondary outcomes. The risk of bias was assessed with the RoB2-tool. This review is registered in PROSPERO with the number (CRD42022376487). From 5129 titles, 580 abstracts were selected, and 111 full-text articles were screened. Finally, 12 articles could be included. Concerning the primary outcomes (MBL and PD), no differences could be seen between titanium abutment and zirconia or alumina abutments, not after 1 year (MBL: zirconia: MD = -0.24, 95% CI: -0.65 to 0.16, alumina: MD = -0.06, 95% CI: -0.29 to 0.17) (PD: zirconia: MD = -0.06, 95% CI: -0.41 to 0.30, alumina: MD = -0.29, 95% CI: -0.96 to 0.38), nor after 5 years. Additionally, no differences were found concerning the biological complications and aesthetic outcomes. The most important technical finding was abutment fracture in the ceramic group and chipping of the veneering material. Biologically, titanium and zirconia abutments seem to function equally up to 5 years after placement.

Root-analogue implants compared to forced orthodontic extrusion: a retrospective analysis of clinical, radiological and esthetic outcomes after restoration

ObjectivesTo assess clinical, radiological and esthetic outcomes of restorations supported by root-analogue implants (RAIs) or roots of severely damaged teeth after forced orthodontic extrusion (FOE).Materials and methodsClinical data regarding milled one-piece (titanium/zirconia roots and zirconia abutments) RAIs (REPLICATE™ System) and FOE were recorded and retrospectively evaluated for 40 patients by two investigators. Strict inclusion and exclusion criteria were applied. Functional and esthetic outcomes were assessed for n = 20 pre-molars and n = 20 anterior teeth via comparison of radiographic and digital images applying the novel Functional Implant Prosthodontic Score (FIPS). Krippendorff’s alpha coefficient was calculated to assess inter-rater reliability. Mann–Whitney-U-Test was used to compare the assessed parameters. Level of significance was set to p < 0.05.ResultsAfter a mean observation period of 18.4 ± 5.7 months for restorations supported by RAIs and 43.9 ± 16.4 months for restorations after FOE, mean FIPS scores were 9.2/8.8 ± 1.1/1.2 (RAIs) and 7.4/7.7 ± 1.3/1.5 (FOE), respectively. Krippendorff’s alpha coefficients did not reveal unacceptable inter-rater reliabilities regarding the investigators and applicability of FIPS. Significant differences were documented when comparing restorations after FOE or supported by RAIs regarding bone loss (p < 0.01), presence of papillae (p < 0.05) and quality and quantity of mucosa (p < 0.02) in favor of FOE.ConclusionsWithin the main limitations of sample size and the retrospective study design, both concepts seem to provide clinically acceptable results.Clinical relevanceBone- and tissue-preserving characteristics regarding the concept of FOE are promising. It could be applicable for socket preservation and subsequent conventional implant placements in an adapted workflow.

Effect of internal connection type and screw channel angle on the screw stability of anterior implant-supported zirconia crowns.

To investigate the effect of implant-abutment connection and screw channel angle on screw stability by comparing a newly introduced and an established connection, before and after cyclic loading. Implants (N = 44) with Torcfit (TF) or Crossfit (CF) connection were divided to be restored with a straight (CFS and TFS) or an angled screw access channel (CFA and TFA) titanium-base abutment (n = 11). CFA and TFA received screw-retained crowns, whereas CFS and TFS received hybrid zirconia abutments and cement-retained crowns. The initial torque value (ITV) of each complex (ITVI ) and removal torque value (RTV) after 24 h (RTVI ) were measured. Screws were replaced with new ones, ITVs were recorded again (ITVF ), and crowns were cyclically loaded (2.4 million cycles, 98 N) to measure RTVs again (RTVF ). Percentage torque loss was calculated. Data were analyzed (α = 0.05). ITVs were similar among groups (p ≥ .089). CF led to higher RTVs (p ≤ .002), while CFS had higher RTVI than CFA (p = .023). After 24 h, CFS had lower percentage torque loss than TF, while CFA had lower percentage torque loss than TFA (p ≤ .011). After cyclic loading, CF led to lower percentage torque (p < .001). The implant-abutment connection affected the removal torque values. However, no screw loosening occurred during cyclic loading, which indicated a stable connection for all groups. Screw access channel angle did not affect screw stability after cyclic loading.

Effect of gingival height of a titanium base on the biomechanical behavior of 2-piece custom implant abutments: A 3-dimensional nonlinear finite element study

Statement of problemTitanium base (TiBase) abutments to restore an implant-supported single crown are available in different gingival heights, but information on the biomechanical effects of the gingival heights is lacking. PurposeThe purpose of this nonlinear finite element analysis study was to evaluate the effects of TiBase gingival heights on the biomechanical behavior of custom zirconia (CustomZir) abutments and TiBase, including von Mises stress and maximum and minimum principal stress. Material and methodsTiBases with different gingival heights (0.5 mm, 1 mm, 1.5 mm, and 2 mm) with internal hexagon Morse taper connections were simulated in 3-dimensional models. The simulations (ANSYS Workbench 2020; ANSYS Inc) included the OsseoSpeed EV implant (Ø5.4 mm) (AstraTech; Dentsply Sirona), restoration, and surrounding bone in the mandibular first molar region. An occlusal force of 200 N was applied with a 2-mm horizontal offset toward the buccal side and a 30-degree inclination from the vertical axis. ResultsHigh-stress concentration was observed in the uppermost internal connection area on the buccal side and the antirotational part of the titanium abutment on the lingual side in all models. CustomZir abutments with a shorter gingival height exhibited larger concentrated areas of volume average stress von Mises stress and higher magnitude of maximum and minimum principal stress compared with a taller gingival height. ConclusionsA TiBase abutment with a taller gingival height reduced the fracture risk of a CustomZir abutment without increasing any mechanical risk.

The effect of different abutment and restorative crown materials on stress distribution in single-unit implant-supported restorations: A 3D finite element stress analysis.

To evaluate the effect of restorative materials with or without resin content, modeled on zirconia and titanium abutment materials, on the stress distribution on the alveolar bone, implant, and prosthetic crowns with a 3D finite element stress analysis. Titanium and zirconia abutments were combined with three implant-supported crown materials (polymer infiltrated hybrid ceramic (PICN), lithium disilicate (LD), and zirconia-reinforced lithium silicate (ZLS)) to create six experimental groups. The 40×30×20mm alveolar bone, 3.75× 10mm implant, esthetic abutment, and maxillary first premolar crown bonded over the abutment were the components of the finite element models. On the lingual cusp of the crown, the 150 N occlusal loading was applied in the buccolingual direction at a 30° angle. Equivalent von Mises stress and maximum and minimum principal stresses were used for both the qualitative and quantitative evaluation of the stress distribution of the created models. The von Mises stress in implant and abutment did not differ according to the crown materials. The use of a zirconia abutment resulted in higher von Mises stress values in the abutment but lower stress values in the implant. The highest stress values were obtained in ZLS (196.65MPa) and LD (194.05MPa) crowns. The use of titanium abutments, regardless of crown materials, resulted in higher von Mises stress values in restorative crowns than in zirconia abutments. The principal stress values in alveolar bone showed similar distribution and concentration in all models. Changes in crown material did not affect stress distribution in the implant and peripheral bone. However, the zirconia esthetic abutment resulted in a lower stress concentration on the implant.

Can patients detect peri‑implant mucosal inflammation? Results from a multicentre randomized trial

PurposeThe objective of this study was to compare patient-reported outcomes (PROs) of peri‑implant soft tissue inflammation and aesthetics around single-tooth implants in the anterior maxillary region with three different implant-abutment interface designs. MethodsParticipants were randomized to one of three different types of implant-abutment interface designs [Conical (CI), flat-to-flat (FI), and Platform Switched (PS)]. Implants and provisional crowns with prefabricated titanium abutments were placed 5 months following extraction and/or ridge augmentation. Permanent ceramic crowns with zirconia abutments were placed after 12 weeks. To assess PROs, appearance and inflammation questionnaires were completed from provisional crown placement to the 3-year follow-up. ResultsTooth appearance at the 3-year follow-up revealed a difference amongst CI, FI and PS implants (p=0.049; Kruskal-Wallis test). PS was rated better than FI (p=0.047) at 1 year for appearance of soft-tissue and satisfaction with colour. There were no differences for self-consciousness, smile and pain/discomfort while eating/hard food items. ConclusionsAlthough participants tended to rate the health of mucosa around PS implants as slighty better than the other two implant systems, the differences were minimal and inconsistent. Thus, patient satisfaction in terms self-perceived gingival health and esthetics was high for all 3 systems tested, suggesting that patients are unable to detect mucosal inflammation. Clinical SignificancePatients find it difficult to perceive mucosal inflammation; hence, it is recommended that patients attend implant follow-up visits, even if they do not perceive inflammation. The study suggests that there is a relationship between the PROs and the clinical outcomes of tested implants.

Effect of calcium hydrothermal treatment of zirconia abutments on human gingival fibroblasts.

Zirconia materials have been increasingly used in implant rehabilitation due to their excellent physical and esthetic properties. Stable peri-implant epithelial tissue adhesion to the transmucosal implant abutment may significantly enhance the efficacy of implant long-term stability. However, it is difficult to form stable chemical or biological bindings with peri-implant epithelial tissue due to the strong biological inertia of zirconia materials. In the present study, we investigated whether calcium hydrothermal treatment of zirconia promotes sealing of peri-implant epithelial tissue. In vitro experiments were performed to analyze the effects of calcium hydrothermal treatment on zirconia surface morphology and composition by scanning electron microscopy and energy dispersive spectrometry. Immunofluorescence staining of adherent proteins, namely, F-actin and integrin β1, in human gingival fibroblast line (HGF-l) cells was performed. In the calcium hydrothermal treatment group, there was higher expression of these adherent proteins and increased HGF-l cell proliferation. An in vivo study was conducted by extracting the maxillary right first molars of rats and replacing them with mini-zirconia abutment implants. The calcium hydrothermal treatment group showed better attachment at the zirconia abutment surface, which inhibited horseradish peroxidase penetration at 2 weeks post-implantation. These results demonstrated that calcium hydrothermal treatment of zirconia improves the seal between the implant abutment and surrounding epithelial tissues, potentially increasing the long-term stability of the implant.

Effect on the Fracture Resistance of Monolithic Zirconia Custom Abutment in Different Angulation: An In Vitro Study

The study was designed to find out the effect of different angulations of monolithic Zirconia custom-made abutments on fracture resistance. In this experimental type in vitro study, a total of thirty implant analogs with a diameter of 4.3 mm and a length of 11.5 mm were obtained for the maxillary central incisor. A total of thirty abutments specimens in three groups- 0-degree, 15-degree, and 25-degree, ten in each group were fabricated with monolithic zirconium by CAD/CAM system. Each abutment was subjected to load until fracture in a Universal testing machine and data was collected to a data collection sheet. One-way ANOVA was done to compare the fracture load among the three groups and pairwise comparison was done by Tukey post hoc test. The statistical significance p-value was considered as less than 0.05. The range of fracture load of 0-degree, 15-degree, and 25-degree angulated abutments were 590.55-1305.43N, 755.89-1720.55N, and 496.68-820.88N respectively. The highest fracture resistance was shown in 15-degree angulated custom-made zirconium abutments with a mean ± SD of 1223.442 ± 317.771N and the lowest fracture resistance was shown in case 25-degree with a mean ± SD deviation of 653.139 ± 102.045N. The mean ± SD of the 0-degree abutment was 948.944±245.588N. 95% Confidence interval of the mean were 773.260-1124.627N, 996.122-1450.761N, and 580.140-726.137N were assessed in cases of 0-degree, 15-degree, and 25-degree respectively. The fracture load or fracture resistance among the three groups of custom-made monolithic zirconium abutments were significantly different. 15-degree angulated abutment had higher fracture resistance properties. straight abutment had more fracture resistance properties than that of 25-degree abutments, but less than 25-degree abutments.

The Effect of Zirconia and Titanium as Abutment Materials on Peri-Implant Soft and Hard Tissues in Mandibular Implant Supported Over-denture

Purpose: To evaluate the effect of zirconia and titanium as abutment materials onperi-implant bone height changes and pocket depth in mandibular implant supportedover-denture. Subjects and methods: Ten completely edentulous patients wereselected from the Outpatient Clinic of the Faculty of Dental Medicine for Girls,Al-Azhar University. Two implants were implanted in the inter-foraminal area ofmandibular ridge. Two different abutments were screwed over implants. Right abutmentwas constructed of zirconia and left one was constructed of titanium. Construction ofmaxillary complete denture and mandibular implant supported over-denture for allpatients was performed. Radiographic and clinical evaluation of implants has beenperformed at denture insertion, 6 months, 9 months and 12 months. Results: Theprevious study illustrated that titanium abutments had significantly higher values ofbone height changes and pocket depth measurements than zirconia abutments duringfollow up period. Conclusion: Zirconia abutments had great superiority over titaniumabutments in preservation of peri-implant hard and soft tissues in mandibularimplant-supported over-denture within the follow up period of this study.

The Effect of Zirconia and Titanium as Abutment Materials on Peri-Implant Soft and Hard Tissues in Mandibular Implant Supported Over-denture

Purpose: To evaluate the effect of zirconia and titanium as abutment materials onperi-implant bone height changes and pocket depth in mandibular implant supportedover-denture. Subjects and methods: Ten completely edentulous patients wereselected from the Outpatient Clinic of the Faculty of Dental Medicine for Girls,Al-Azhar University. Two implants were implanted in the inter-foraminal area ofmandibular ridge. Two different abutments were screwed over implants. Right abutmentwas constructed of zirconia and left one was constructed of titanium. Construction ofmaxillary complete denture and mandibular implant supported over-denture for allpatients was performed. Radiographic and clinical evaluation of implants has beenperformed at denture insertion, 6 months, 9 months and 12 months. Results: Theprevious study illustrated that titanium abutments had significantly higher values ofbone height changes and pocket depth measurements than zirconia abutments duringfollow up period. Conclusion: Zirconia abutments had great superiority over titaniumabutments in preservation of peri-implant hard and soft tissues in mandibularimplant-supported over-denture within the follow up period of this study.

3D-printing bionic-patterned zirconia via stereolithography promotes soft tissue integration for ceramic implants

Due to the desirable aesthetic performance, zirconia abutments attract tremendous attention in implant related restoration of the anterior zone. However, the inadequate soft tissue integration originated from the inertia surface of zirconia severely limits its application. Fabricating bionic-patterned zirconia abutments is believed to be a promising strategy to solve this puzzle. The main obstacle to fabricating bionic-pattern lies in that conventional zirconia manufacturing technology cannot precisely engineer complex micro-pattern. Notably, modern 3D printing presents a feasible way to obtain various sophisticated topological architecture. In the present study, series of bionic-patterned zirconia were fabricated by 3D printing, simulating lotus leaf, butterfly wings, shark skin, and gecko foot. The features of micro-patterns and quality of 3D printing were systematically characterized. In addition, the effect of various bionic-patterned zirconia on the behaviors of gingival fibroblasts was investigated. Results showed that zirconia with various micro-scale bionic patterns was successfully and precisely fabricated by 3D printing. Among the four types of bionic patterns, the ones that resembled the geckos’ feet or lotus leaves were the most recommended topography for cell growth and spreading, while the pattern mimicked shark skin upgraded the expression of fibroblast functional genes including Col-I, Fn, and Itgb-1 most obviously. The bionic-patterned zirconia can efficiently promote adhesion, proliferation, and related gene expression of gingival fibroblasts, indicating that bionic-patterned zirconia has great potential to promote soft tissue integration.

Digital evaluation of the effect of nanosilica-lithium spray coating on the internal and marginal fit of high translucent zirconia crowns

ObjectivesTo evaluate the effect of a nanosilica–lithium spray coating on the internal and marginal fit of high translucent zirconia crowns using a digital evaluation method. MethodsA three-dimensional analysis model of a zirconia abutment was digitally scanned using a dental scanner, and 30 monolithic high translucent zirconia crowns were designed and fabricated. They were divided into groups (n = 10) according to the surface treatment method: (1) no treatment: as-sintered zirconia; (2) airborne-particle abrasion with 50 μm Al2O3 particles; and (3) nanosilica–lithium spray coating. Three-dimensional data for the abutment, crown, and crown seated on the abutment were obtained using a dental scanner. The three-dimensional seated fit between the crown and abutment was reconstructed using registration technology, and a three-dimensional (3D) deviation analysis was used to evaluate the effect of different modification methods on the internal and marginal fit of the crowns using root mean square (RMS) values. ResultsThe 3D deviation analysis of all groups conformed to a normal distribution (P > 0.05), and the variance was homogeneous (P > 0.05). The different surface treatments had no significant effect on the RMS values in the occlusal, axial, and marginal regions of the high translucent zirconia crowns (P > 0.05). ConclusionsNanosilica-lithium spray coating for the modification of as-sintered zirconia is clinically feasible and does not affect the internal or marginal fit of high translucent zirconia crowns. Clinical significanceNanosilica–lithium spray coating does not affect the adaptation of zirconia crowns and is a clinically feasible surface treatment method for zirconia. It is unnecessary to add the setting values of the internal and marginal fit when fabricating nanosilica–lithium-sprayed zirconia crowns.

Wear of Titanium Implant Platforms with Different Abutment Connections and Abutment Materials: A Pilot Study

The most commonly used material in dental implants and their abutments is titanium. Zirconia is a more aesthetic alternative to titanium abutments; however, it is much harder. There are concerns that zirconia could damage the surface of the implant over time, especially in less stable connections. The aim was to evaluate the wear of implants with different platforms connected to titanium and zirconia abutments. A total of six implants were evaluated, two of each connection type: external hexagon, tri-channel, and conical connections (n = 2). Half of the implants were connected to zirconia abutments, and the other half to titanium abutments (n = 3). The implants were then cyclically loaded. The implant platforms were evaluated by digital superimposing micro CT files and calculating the area of the loss surface (wear). In all the implants, a statistically significant loss of the surface area (p = 0.028) was observed when comparing the area before and after cyclic loading. The average lost surface area was 0.38 mm2 with titanium abutments and 0.41 mm2 with zirconia abutments. The average lost surface area was 0.41 mm2 with the external hexagon, 0.38 mm2 with the tri-channel, and 0.40 mm2 with the conical connection. In conclusion, the cyclic loads induced implant wear. However, neither the type of abutment (p = 0.700) nor the connection (p = 0.718) influenced the amount of surface area lost.

Clinical and immunological evaluation of peri-implant tissues around ultra-polished and conventional smoothness zirconia abutments. A 1-year follow-up randomized clinical trial.

This is a randomized clinical trial to compare the clinical and immunological performance of ultrasmooth versus regular-smooth zirconia abutments placed subgingivally after a period of 1 year. Sixty-two bone level platform-switched implants (NobelParallel CC) were placed epicrestally in the mandibular molar or premolar region in 62 patients. After osseointegration, implants were restored with auto polymerizing acrylic resin crowns and subsequently randomly allocated to 2 groups according to the type of screw-retained zirconia crown prescribed. The control group received custom zirconia restoration with the subgingival zirconia part conventionally polished, while the test group implants were restored with ultra-polished zirconia abutments. Periodontal parameters (PD, PI, BOP) and marginal bone level changes (MBLC) were recorded for each implant 2 months after insertion (T0), 1 month after final delivery of the crown (T2) and at the 1-year follow-up (T3). Immunological mediators from GCF (IL-1α, IL-1ra and TNF-α) were inspected at 1 month after provisional (T1) and accordingly at T2 and T3. Data was analyzed statistically, and significance level was set to α = 0.05. After 1-year, there were no significant changes in PD control - 2.18 ±0.89 mm and test - 2.5 ±0.72 mm (p = 0.073). PD between T2 and T3 dropped significantly in the test group (p = 0.037), and remained stable in the control group. PI was not different in both groups at T0 (p = 0.518) and T2 (p = 0.817). At T3, the test group (0.9 ±1.01) had a significantly lower PI than the control group (1.55 ±1.23) (p = 0.035). There was no difference in BOP positive cases between groups after 1 year (control - 61.3%, test - 51.7%, p = 0.455). The amount of IL-1ra decreased significantly in the test group (41.75 ±57.58) (p = 0.001) but not in the control group (59.59 ± 70.43) (p = 0.177). MBLC for the control and test groups after 1 year were 0.68 ±0.7 mm and 0.94 ±0.65 mm (p = 0.061). PD dynamics, PI, BOP and IL-1ra revealed better outcomes around ultra-polished zirconia abutments than around conventionally polished zirconia abutments. This article is protected by copyright. All rights reserved.

Screw-retained internal connection zirconia CAD-CAM abutments in single implant reconstructions: Results of a 1-year prospective case series study.

To evaluate the clinical and radiographic outcomes of single-tooth implant restorations using one-piece, internally connected, screw-retained, computer-aided design and computer-aided manufactured monolithic zirconia restorations fabricated on regular diameter implants. Following a 2-stage surgical procedure, 22 implants placed in anterior and posterior areas in 21 partially edentulous patients (mean age of 55 years; 9 males/12 females) were evaluated in terms of plaque index, pocket probing depth, bleeding on probing, level of oral hygiene (OH), signs of mucositis/peri-implantitis, esthetic score (ES), gingival zenith position (GZP), papilla index score, the thickness of peri-implant gingiva, radiographic marginal bone loss, and technical complications. Implants and restorations were prospectively followed from the insertion of the restoration (baseline), up to 12-months post-loading. A 100% implant survival rate resulted after loading; one implant was lost before loading. Clinically, patients performed an adequate OH, and tissues were kept healthy. Probing depth showed a slightly lower value at baseline compared to any follow-up examination (2.26 [0.94] at baseline vs. 2.53 [0.66]mm at 12 months). ES, GZP, and the thickness of the peri-implant gingiva improved throughout the course of the study. Radiographically, average marginal bone level (MBL) was 0.40 (0.40)mm after 1-year follow-up with no differences in average MBL at all time points. Technically, after 1 year of clinical function, neither abutment fracture nor any other serious complications occurred. Hence, prosthetic reconstruction survival rate was 100%. Clinical outcomes of single-tooth implant restorations using internally connected, screw-retained, computer-aided design and computer-aided manufacturing monolithic zirconia abutments can be considered a reliable treatment alternative after 1-year clinical observation.

The clinical use of computer aided designed/computer aided manufactured titanium nitride coated implant abutments: Surgical and prosthetic considerations-A case series.

To describe the clinical use of nitride-coated titanium CAD/CAM implant abutments in the maxillary esthetic zone in two patients with high esthetic and functional demands and, to highlight the advantages of nitride-coated milled titanium abutments when compared to stock/custom titanium, one-piece monolithic zirconia, and hybrid metal-zirconia implant abutments. Due to the inherent mechanical and esthetic clinical challenges, single implant-supported reconstructions in the maxillary esthetic zone are a complex restorative treatment. While CAD/CAM technology has been suggested to enhance and ease implant abutment design and manufacturing, implant abutment material selection remains as a critical decision affecting restoration's long-term clinical outcomes. To date, considering the esthetic disadvantages of conventional titanium implant abutments, the mechanical limitations of one-piece zirconia abutments and the manufacturing time and costs associated with hybrid metal-zirconia abutments, no abutment material can be considered "ideal" for all clinical scenarios. Due to their biocompatibility, biomechanical characteristics (hardness and wear resistance), optical properties (yellow color), and peri-implant soft tissue esthetic integration, the use of CAD/CAM titanium nitride-coated implant abutments has been suggested as a predictable implant abutment material in mechanically challenging but esthetically demanding clinical situations, as the maxillary esthetic zone. Two patients requiring a combined tooth-implant restorative treatment in the maxillary esthetic zone were treated using CAD/CAM nitride coated titanium implant abutments. The principal advantages of TiN coated abutments include comparable clinical outcomes to stock abutments, optimal biocompatibility, adequate fracture, wear, and corrosion resistance, reduced bacterial adhesion, and excellent esthetic integration with adjacent soft tissues. Clinical reports and short term mechanical, biological and esthetic clinical outcomes indicate that CAD/CAM nitride coated titanium implant abutments can represent a predictable restorative alternative to stock/custom and metal/zirconia implant abutments and be considered a clinical relevant option in mechanically challenging but esthetically demanding situations, as often found in the maxillary esthetic zone.

Promotional Effect and Molecular Mechanism of Synthesized Zinc Oxide Nanocrystal on Zirconia Abutment Surface for Soft Tissue Sealing

Studies have confirmed that tooth loss is closely related to systemic diseases, such as obesity, diabetes, cardiovascular diseases, some types of tumors, and Alzheimer’s disease. Among many methods for tooth restoration, implant restoration is the most commonly used method. After implantation, long-term stability of implants requires not only good bone bonding but also good soft tissue sealing between implants and surrounding soft tissues. The zirconia abutment is used in clinical implant restoration treatment, but due to the strong biological inertia of zirconia, it is difficult to form stable chemical or biological bonds with surrounding tissues. In this study, we investigated synthesized zinc oxide (ZnO) nanocrystal on the zirconia abutment surface by the hydrothermal method to make it more beneficial for soft tissue early sealing and the molecular mechanism. In vitro experiments found that different hydrothermal treatment temperatures affect the formation of ZnO crystals. The crystal diameter of ZnO changes from micron to nanometer at different temperatures, and the crystal morphology also changes. In vitro, scanning electron microscopy, energy dispersive spectrometry, and real-time polymerase chain reaction results show that ZnO nanocrystal can promote the attachment and proliferation of oral epithelial cells on the surface of zirconia by promoting the binding of laminin 332 and integrin β4, regulating the PI3K/AKT pathway. In vivo, ZnO nanocrystal ultimately promotes the formation of soft tissue seals. Collectively, ZnO nanocrystal can be synthesized on a zirconia surface by hydrothermal treatment. It can help to form a seal between the implant abutment and surrounding soft tissue. This method is beneficial to the long-term stability of the implant and also can be applied to other medical fields.

Marginal and internal fit of five-unit zirconia fixed dental prostheses fabricated with digital scans and conventional impressions: A comparative in vitro study.

This study aimed to compare the marginal and internal fit of five-unit zirconia fixed dental prostheses fabricated using digital scans and conventional impressions. Nine master models with three zirconia abutments were scanned with an intraoral scanner (test group), and nine conventional impressions (control group) of these same models were also made. The stone casts from theses impressions were scanned with a laboratory extraoral scanner (D700, 3Shape, Copenhagen, Denmark). A total of 18 five-unit zirconia fixed dental prostheses frameworks (test group, n = 9; control group, n = 9) were manufactured. Marginal and internal fit (in μm) were evaluated using the replica method under micro-computed tomography. Analysis of variance (one-way ANOVA) and Kruskal Wallis tests were used to compare continuous variables across two groups. A level of P <0.05 was accepted as statistically significant. The mean ±standard deviation of the marginal fit was 95.03 ±12.74 μm in the test group and 106.02 ±14.51 μm in the control group. The lowest marginal mean value was observed in the test group, with a statistically significant difference comparing to the control group (F = 14. 56, P <0.05). The mean ±standard deviation of the internal fit was 103.61 ±9.32 μm and 106.38 ±7.64 μm, respectively, in the test and control groups, with no statistically significant difference (F = 1.56, P >0.05). The mean values of both groups were clinically acceptable. The five-unit zirconia fixed dental prostheses fabricated with digital scans showed better fit than conventional impressions group. Within the limitations of this study, these results are encouraging and continued progress in the digital field should allow for more accurate long-span restorations. This article is protected by copyright. All rights reserved.

Implant–Prosthetic Rehabilitation of Maxillary Lateral Incisor Agenesis with Narrow Diameter Implants and Metal–Ceramic vs. All-Ceramic Single Crowns: A 16-Year Prospective Clinical Study

The main objectives of the present prospective clinical study were to evaluate the marginal bone resorption and the peri-implant soft tissue conditions around narrow diameter implants, as well as the clinical performances of metal–ceramic and all-ceramic single crowns in the implant–prosthetic treatment of maxillary lateral incisors agenesis. Seventy-two patients affected by monolateral or bilateral agenesis of the maxillary lateral incisors were included in the study, and a total of 105 narrow diameter implants were inserted. The final single crowns were fabricated 4 months after the surgical procedures by means of either titanium abutments with Auro-Galvan Crowns (AGC) veneered with feldspathic ceramics or zirconia abutments with all-ceramic (alumina or zirconia) crowns layered with dedicated veneering ceramics. Both marginal bone resorption and soft tissue quality were evaluated after a maximum period of 16 years. Two independent survival curves for patients wearing AGC or all-ceramic crowns were calculated by means of Kaplan–Meier analysis, and a log-rank test was performed in order to compare these curves (p &lt; 0.05). After 16 years of clinical function, a mean marginal bone resorption of 1.2 ± 0.61 mm and good response of peri-implant soft tissues were observed. Descriptive statistics resulted in 80% and 87.1% cumulative success rates for patients provided with AGC prostheses onto titanium abutments and all-ceramic crowns on-to zirconia abutments, respectively. The cumulative survival rate calculated for AGC group was 93.3%, whereas all-ceramic group showed a cumulative survival rate of 95.7%. No statistically significant differences were found with the log-rank tests. The overall success and survival rates calculated were 85% and 95% for all the restorations, respectively. Mucositis, abutment unscrewing, loss of retention, chipping, core fracture, and esthetic failure were the major complications reported. The implant–prosthetic approach can be considered an effective and viable solution to treat cases of maxillary lateral incisor agenesis in the long term.

An insight performance of zirconia implant abutment: A systematic review and meta-analysis of randomized controlled clinical trial.

To determine the clinical performance of zirconia abutment (ZA) by comparing with a titanium abutment (TA) and sub-mucosal-modified zirconia abutment. A systematic search was conducted to retrieve eligible randomised controlled trials (RCTs) from Medline, Cochrane Library, SCOPUS, Embase, Web of Science, and Google Scholar. A search was further divided in two parts. Part I comprises eligible RCTs between zirconia abutment and titanium abutment, and part II included RCTs of zirconia abutment with sub-mucosal modified, pink-veneered glass ceramic versus non-veneered zirconia abutment. Esthetic, biological, and abutment survival was a primary outcome, and technical complications were included as an additional outcome. Fifteen eligible RCTs (Part I: N = 9 and Part II: N = 6) were evaluated, and a total of 362 abutments in 364 subjects were analysed for outcome variables. A sub-group meta-analysis reported no significant difference for Esthetic outcome. However, the overall mean (p =0.03) was higher for zirconia group in those of thin gingival phenotype. Spectrophotometric evaluation of peri-implant mucosal Esthetic does not show any significant difference. Similarly, pink-veneered versus non-veneered group reported no significant difference for thin (<2 mm) and thick (>2 mm) mucosal attachment. Biological outcome does not show any significant difference for comparable groups in both parts. There is marginally lower abutment survival for internally connected zirconia abutment (ZA: 95.4% TA: 100%). Zirconia abutment exhibited excellent Esthetic compared to titanium abutment in those of thin gingival phenotype. Sub-mucosa veneering of zirconia abutment with pink glass ceramic does not show any favourable Esthetic outcome compared to the non-veneered surface.