Sphere-plane methodology to evaluate the wear of titanium of dental implants: a research proposal.
ABSTRACT: Titanium is the most commonly used material to manufacture dental implants and abutments. Recently, zirconia abutments have been manufactured with better aesthetic properties. However, zirconia abutments are harder than titanium implants; therefore, they could wear the implant surface. Therefore, this article aims to describe a sphere-plane system that can be used to assess the wear that different abutment materials cause in the titanium of dental implants when submitted to cyclic loading. This method can be used to simulate the oral cavity, where the abutment (sphere) applies loads onto the implant (titanium plane). The spheres were made of different materials (titanium and zirconia), and the specimens were loaded for 4,000,000 cycles. The scar size and area on titanium planes were measured with stereoscopic images and analysed through profilometry.The wear of titanium planes was similar when tested against zirconia or titanium spheres. The sphere-plane system is a method that can be used to evaluate and quantify the wear of the titanium of dental implants, and compared with methods that use real implants, this system is simpler and less expensive. This method could facilitate further research to evaluate the wear of titanium against different materials and under different testing conditions.
Project description:Dental implant abutments are fundamental prosthetic components within dentistry that require optimal biocompatibility. The primary aim of this cross-sectional study was to preliminarily assess differences in the pro-inflammatory cytokine and bone metabolism mediator protein expression in the peri-implant crevicular fluid (PICF) adjacent to transmucosal abutments.Abutments were fabricated from either titanium or zirconia in patients previously receiving single-tooth implant therapy. All subjects sampled in this study had an identical implant system and implant-abutment connection. Participants (n = 46) had an average time of clinical function for 22 months (6.2-72.8 months, ±SD 17 months) and received a clinical and radiographic examination of the implant site at the time of PICF sampling using a paper strip-based sampling technique. Cytokine, chemokine, and bone metabolism mediator quantities (picograms/30 s) were determined using a commercial 22-multiplexed fluorescent bead-based immunoassay instrument. A total of 19 pro-inflammatory cytokines and seven bone metabolism mediators were evaluated.Multivariable analyses provided no evidence of a group (titanium or zirconia), gender, or age effect with regard to the expression of pro-inflammatory mediators evaluated. Significant (P = 0.022) differences were observed for the bone mediator leptin, with titanium abutments demonstrating significantly elevated levels in comparison with zirconia. Osteopontin demonstrated a significant (P = 0.0044) correlation with age of the subjects.No significant differences in pro-inflammatory cytokine or bone metabolism mediator profiles were observed biochemically, with the exception of leptin, for the abutment biomaterials of titanium or zirconia The molecular PICF findings support the observed clinical biocompatibility of both titanium and zirconia abutments.
Project description:BACKGROUND:Artificial intelligence (AI) is a branch of computer science concerned with building smart software or machines capable of performing tasks that typically require human intelligence. We present a protocol for the use of AI to fabricate implant-supported monolithic zirconia crowns (MZCs) cemented on customized hybrid abutments. METHODS:The study protocol consisted of: (1) intraoral scan of the implant position; (2) design of the individual abutment and temporary crown using computer-aided design (CAD) software; (3) milling of the zirconia abutment and the temporary polymethyl-methacrylate (PMMA) crown, with extraoral cementation of the zirconia abutment on the relative titanium bonding base, to generate an individual hybrid abutment; (4) clinical application of the hybrid abutment and the temporary PMMA crown; (5) intraoral scan of the hybrid abutment; (6) CAD of the final crown with automated margin line design using AI; (7) milling, sintering and characterisation of the final MZC; and (8) clinical application of the MZC. The outcome variables were mathematical (quality of the fabrication of the individual zirconia abutment) and clinical, such as (1) quality of the marginal adaptation, (2) of interproximal contact points and (3) of occlusal contacts, (4) chromatic integration, (5) survival and (6) success of MZCs. A careful statistical analysis was performed. RESULTS:90 patients (35 males, 55 females; mean age 53.3?±?13.7?years) restored with 106 implant-supported MZCs were included in the study. The follow-up varied from 6 months to 3 years. The quality of the fabrication of individual hybrid abutments revealed a mean deviation of 44??m (± 6.3) between the original CAD design of the zirconia abutment, and the mesh of the zirconia abutment captured intraorally at the end of the provisionalization. At the delivery of the MZCs, the marginal adaptation, quality of interproximal and occlusal contacts, and aesthetic integration were excellent. The three-year cumulative survival and success of the MZCs were 99.0% and 91.3%, respectively. CONCLUSIONS:AI seems to represent a reliable tool for the restoration of single implants with MZCs cemented on customised hybrid abutments via a full digital workflow. Further studies are needed to confirm these positive results.
Project description:Two-piece abutments consisting of customized zirconia abutment copings and prefabricated titanium bases are popular due to their biological and esthetic advantages. Glass-ceramic solder (GS) is an alternative biocompatible connective agent. This in vitro study evaluated the retentive force of GS in comparison to classical resin composite cements (RC) after artificial aging and autoclaving. Ninety specimens consisting of prefabricated titanium bases and zirconia abutment copings were fabricated. The two parts of each specimen were fixed either by RC (n = 30) or GS with a luting space of either 30 µm (n = 30) or 100 µm (n = 30). Ten specimens of each group underwent autoclaving before artificial aging (water storage, thermocycling). Twenty specimens (including the 10 autoclaved specimens) of each group were exposed to a mechanical load. The retentive force between the zirconia and titanium in all specimens was determined. A fractographic analysis was performed to analyze the fracture surfaces of the GS specimens. The RC- and GS-connected two-piece abutments showed no relevant differences, independent of the luting space. RC appears to be more vulnerable to the thermal and mechanical loads than GS. Thus, GS may be an appropriate alternative to RC for two-piece abutments, especially for patients with enhanced biocompatibility requirements.
Project description:The aim of the present study is to evaluate, in a ligature-induced peri-implantitis model, the efficacy of three antimicrobial glassy coatings in the prevention of biofilm formation, intrasulcular bacterial growth and the resulting peri-implant bone loss.Mandibular premolars were bilaterally extracted from five beagle dogs. Four dental implants were inserted on each hemiarch. Eight weeks after, one control zirconia abutment and three with different bactericidal coatings (G1n-Ag, ZnO35, G3) were connected. After a plaque control period, bacterial accumulation was allowed and biofilm formation on abutments was observed by Scanning Electron Microscopy (SEM). Peri-implantitis was induced by cotton ligatures. Microbial samples and peri-implant crestal bone levels of all implant sites were obtained before, during and after the breakdown period.During experimental induce peri-implantitis: colony forming units counts from intrasulcular microbial samples at implants with G1n-Ag coated abutment remained close to the basal inoculum; G3 and ZnO35 coatings showed similar low counts; and anaerobic bacterias counts at control abutments exhibited a logarithmic increase by more than 2. Bone loss during passive breakdown period was no statistically significant. Additional bone loss occurred during ligature-induce breakdown: 0.71 (SD 0.48) at G3 coating, 0.57 (SD 0.36) at ZnO35 coating, 0.74 (SD 0.47) at G1n-Ag coating, and 1.29 (SD 0.45) at control abutments; and statistically significant differences (p<0.001) were found. The lowest bone loss at the end of the experiment was exhibited by implants dressing G3 coated abutments (mean 2.1; SD 0.42).Antimicrobial glassy coatings could be a useful tool to ward off, diminish or delay peri-implantitis progression.
Project description:The goal of the current study is to assess the difference in connective tissue adherence to laser microtextured versus machined titanium abutments.Six patients were selected and each of them received 2 implants, one combined with a laser treated abutment and one with a machined abutment. After three months, the abutments were retrieved together with their surrounding gingival tissue for histological analysis. Qualitative and quantitative evaluation of microscopical images was performed to assess the presence or absence of adherence between the soft tissues and the abutment, and the percentage of soft tissue adhered to the two different surfaces.Intimate adherence between connective tissue and the laser treated abutments, while on machined abutments no adherence was detected. A significant difference was found in the percentage of surface in contact with soft tissue between both implant abutments p=0.03.Within the limitation of the current study, it can be concluded that connective tissues show enhanced adherence to microtextured abutments compared to machined abutments.
Project description:Percutaneous implants, such as bone conduction hearing implants, suffer from complications that include inflammation of the surrounding skin. A sealed skin-abutment interface can prevent the ingress of bacteria, which should reduce the occurrence of peri-abutment dermatitis. It was hypothesized that a hydroxyapatite (HA)-coated abutment in conjunction with soft tissue preservation surgery should enable integration with the adjacent skin. Previous research has confirmed that integration is never achieved with as-machined titanium abutments. Here, we investigate, in vivo, if skin integration is achievable in patients using a HA-coated abutment.One titanium abutment (control) and one HA-coated abutment (case) together with the surrounding skin were surgically retrieved from two patients who had a medical indication for this procedure. Histological sections of the skin were investigated using light microscopy. The abutment was qualitatively analyzed using scanning electron microscopy.The titanium abutment only had a partial and thin layer of attached amorphous biological material. The HA-coated abutment was almost fully covered by a pronounced thick layer of organized skin, composed of different interconnected structural layers.Proof-of-principle evidence that the HA-coated abutment can achieve integration with the surrounding skin was presented for the first time.
Project description:<h4>Objectives</h4>The purpose of this systematic review was to evaluate the impact of the abutment characteristics on peri-implant tissue health and to identify the most suitable material and surface characteristics.<h4>Methods</h4>A protocol was developed aimed to answer the following focused question: "Which is the effect of the modification of the abutment design in regard to the maintenance of the peri-implant soft tissue health?" Further subanalysis aimed to investigate the impact of the abutment material, macroscopic design, surface topography and surface manipulation. Randomised controlled trials (RCTs) with a follow-up of at least 6 months after implant loading were considered as inclusion criteria. Meta-analyses were performed whenever possible.<h4>Results</h4>Nineteen final publications from thirteen investigations were included. The results from the meta-analysis indicated that zirconia abutments (Zi) experienced less increase in BOP values over time [n = 3; WMD = -26.96; 95% CI (-45.00; -8.92); p = .003] and less plaque accumulation [n = 1; MD = -20.00; 95% CI (-41.47; 1.47); p = .068] when compared with titanium abutments (Ti). Bone loss was influenced by the method of abutment decontamination [n = 1; MD = -0.44; 95% CI (-0.65; -0.23); p < .001]. The rest of the studied outcomes did not show statistically significant differences.<h4>Conclusions</h4>The macroscopic design, the surface topography and the manipulation of the implant abutment did not have a significant influence on peri-implant inflammation. In contrast, the abutment material demonstrated increased BOP values over time for Ti when compared to Zi abutments.
Project description:BACKGROUND:Removal of cement-retained implant fixed restorations when needed, can be challenging. Conventional methods of crown removal are time consuming and costly for patients and practitioners. This research explored the use of two different types of pulsed erbium lasers as a non-invasive tool to retrieve cemented zirconia crowns from zirconia implant abutments. MATERIALS AND METHODS:Twenty identical zirconia crowns were cemented onto 20 identical zirconia prefabricated abutments using self-adhesive resin cement. The specimens were divided into two groups for laser assisted crown removal; G1 for erbium-doped yttrium aluminum garnet laser (Er:YAG), and G2 for erbium, chromium-doped yttrium, scandium, gallium and garnet (Er,Cr:YSGG). For the G1, after the first crown removal, the specimens were re-cemented and removed again using the Er:YAG laser. Times needed to remove the crowns were recorded and analyzed using ANOVA (? = 0.05). The surfaces of the crown and the abutment were further examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses. RESULTS:The average times of zirconia crown removal from zirconia abutments were 5 min 20 sec and 5 min 15 sec for the Er:YAG laser of first and second experiments (G1), and 5 min 55 sec for the Er,Cr:YSGG laser experiment (G2). No statistical differences were observed among the groups. SEM and EDS examinations of the materials showed no visual surface damaging or material alteration from the two pulsed erbium lasers. CONCLUSIONS:Both types of pulsed erbium lasers can be viable alternatives for retrieving a zirconia crown from a zirconia implant abutment. Despite operating at different wavelengths, the Er:YAG and Er,Cr:YSGG lasers, perform similarly in removing a zirconia crown from a zirconia implant abutment with similar parameters. There are no visual and elemental composition damages as a result of irradiation with pulsed erbium lasers.
Project description:In the present work, dicationic imidazolium-based ionic liquids (ILs) were investigated as multi-functional coatings on a zirconia (ZrO?) surface to prevent biofilm formation and enhance the wear performance of zirconia while maintaining the material's compatibility with host cells. ILs containing phenylalanine and methionine were synthesized and deposited on zirconia. Intermolecular interactions driving IL deposition on zirconia were studied using X-ray photoelectron spectroscopy (XPS). Anti-biofilm activity and cell compatibility were evaluated in vitro after one and seven days, and wear performance was tested using a pin-on-disk apparatus. ILs were observed to form strong hydrogen bonds with zirconia. IL containing phenylalanine formed a stable film on the surface after one and seven days in phosphate-buffered saline (PBS) and artificial saliva and showed excellent anti-biofilm properties against Streptococcussalivarius and Streptococcussanguinis. Compatibility with gingival fibroblasts and pre-osteoblasts was maintained, and conditions for growth and differentiation were preserved. A significantly lower coefficient of friction and wear volume loss were observed for IL-coated surfaces as compared to non-coated substrates. Overall, zirconia is an emerging alternative to titanium in dental implants systems, and this study provides additional evidence of the materials' behavior and IL coatings as a potential surface treatment technology for improvement of its properties.
Project description:BACKGROUND:When implants are restored with cement-retained restorations, prosthetic retrievability can be difficult and often requires sectioning using rotary instruments. Sometimes repeated removals of a cement-retained implant crown are needed such as for treatment of peri-implantitis or immediate implant provisionalization. The purpose of this study was to evaluate the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser as a non-invasive treatment modality to remove lithium disilicate crowns from zirconia implant abutments following long-term cementation, repetitive debonding and re-cementation, and short-term retrieval. MATERIAL AND METHODS:Twenty identical lithium disilicate crowns were cemented onto zirconia prefabricated abutments using composite resin cement. Ten cemented crowns were removed at 48 hours after cementation as a short-term group (ST), while another 10 were removed 6 months after cementation as a long-term group (LT). To mimicking repetitive recementation and retrieval, the LT crowns were then recemented and removed after 48 hours as a long-term recemention (LTR) group. The LTR crowns were then again recemented and removed after 48 hours as a long-term repeated recemention (LTRR) group. Er:YAG laser was used to facilitate the retrieval of these crowns. recorded and analyzed using ANOVA and t-test. The surfaces of the crown and the abutment were further examined using light microscopy and scanning electron microscopy (SEM). Temperature changes of the abutment and crown upto 10 minutes were also measured and statistically analyzed (paired t-test). RESULTS:The average times of crown removal from zirconia abutments were 4 minutes (min) and 42 second (sec) in LT to 3 min 24 sec in LTR, and 3 min 12 sec in LTRR and ST groups. LTR took the longest time to remove, statistically (ANOVA and t-test, p < .001). No statistical differences were observed among the removal times of LTR, LTRR, and ST groups (t-test, p = .246, .246 and 1). SEM examination of the material surface showed no visual surface damaging from treatment with Er:YAG laser. The temperatures during irradiation ranged from 18.4°C to 20°C and 22.2°C to 24.5°C (Paired t-test, p < .0001) for the abutment and the crown during irradiation from 1 min to 10 mins. CONCLUSIONS:Long-term cementation can increase time in lithium disilicate crown removal from zirconia abutment using Er:YAG. Er:YAG laser is a non-invasive tool to remove cement-retained implant prostheses and should be considered as a viable alternative to rotary instruments.