BACKGROUND: Osteoblastic responses play a crucial role in the success of oral implants. Enhanced proliferation of osteoblast cells is associated with reduced cell mortality and an increase in bone regeneration. This study aims to evaluate the osteoblastic responses following oral implantation.
METHODS: Osteoblast stem cells were harvested and subsequently cultivated using cell culture techniques. The osteoblastic phenotype of the extracted cells was confirmed by examining the extracellular matrix. Cell morphogenesis on functionalized biomaterial surfaces was assessed through indirect immunofluorescence staining. The cellular response was investigated in the presence of two types of implant materials: titanium (Ti) and alumina-toughened zirconia (ATZ). Cell viability and apoptosis were quantitatively assessed using MTT assays and flow cytometry, respectively.
RESULTS: The survival of osteoblastic lineage cells was moderately reduced post-implantation. Viability in the Ti implant group remained at approximately 86%, while in the ATZ group, it was observed at 75%, which is considered acceptable. Moreover, there was a significant disparity in cell survival between the two implant groups (p < 0.05). Analysis of apoptosis levels at various concentrations revealed that the rate of apoptosis was 3.6% in the control group and 18.5% in the ATZ group, indicating that apoptosis or programmed cell death in the ATZ-treated group had increased nearly four-fold (p < 0.05).
CONCLUSIONS: The findings of this study indicate a reduction in osteoblastic cell line survival following implant treatment, with titanium implants exhibiting superior performance in terms of cell survival. However, it was also noted that the incidence of apoptosis in osteoblast cells was significantly higher in the presence of zirconium-based implants.

UNASSIGNED: Implant success and the state of the surrounding bone require multiple measures, especially in humans, and this study aimed to identify the development of the state of the latter by means of radiographic examination performed during the period of osseointegration as well as investigate the changes in bone density that occur after implant installation and 2 months after functional loading. Implant success rates are affected by bone density at the implant site. Therefore, understanding changes in bone density after dental implant placement is essential, as it correlates with subsequent implant success.
UNASSIGNED: Digital radiographs of 28 implants were taken and evaluated at four intervals: preoperatively, 1 and 3 months postoperatively, and 2 months following placement of the permanent prosthesis. Gray values were measured in different areas around the implants through analyzing X-ray images and measuring bone density around the implants using EzDent - 2D software. The aim of this study was to investigate changes in bone density around implants in three regions: apex, neck, and body, as well as to record average density values during the observation period by measuring digital image gray levels (the gray values of the digital radiographs). This was conducted to determine local bone densities in dental implant recipient sites and to study changes in local bone densities at different intervals, preoperatively and postoperatively and after placement of the prosthesis.
UNASSIGNED: A decrease was observed in gray values proportional to reference values 1-month after implant insertion, but these increased at 3 months after insertion and continued to rise 2 months after placement of the prosthesis in the apical, body, and neck regions of the implant.
UNASSIGNED: Sensor-tuned radiography can be used as an effective method to support clinical follow-ups as well as measure changes in bone densities around implants in critical cases.

OBJECTIVE: To evaluate the effect of continuous perioperative clopidogrel treatment on the osseointegration of titanium implants.
METHODS: A total of 32 New Zealand rabbits were randomly divided between two groups: a clopidogrel group (n = 16) and a control group (n = 16). For 1 week prior to the surgical placement of a titanium implant in their medial femoral condyle, rabbits in the clopidogrel group received 3 mg/kg of clopidogrel daily, and the control group received only the vehicle. This treatment was continued for another 6 weeks postoperatively. At 6 weeks, the rabbits were euthanized and postmortem histologic and histomorphometric evaluation of the implants was performed.
RESULTS: The surgical procedures and postoperative period were uneventful and well tolerated by all animals without any surgical wound dehiscence, signs of infection, or other complication. No implant failure was observed in any of the groups. Histomorphometric analysis showed that bone-to-implant contact (BIC) was 48.77% for the clopidogrel group and 34.65% for the control group, with statistically significant difference between them (P < .001). Moreover, clopidogrel group had significantly greater bone tissue density (40.52% vs 28.74%, respectively; P <.001) and mean trabecular thickness (284.7 μm vs 180.7 μm, respectively; P < .001) in proximity to the implant surface than the control group, while the mean trabecular number had no difference between groups (1.56 vs 1.60, respectively; P = .961).
CONCLUSIONS: The present study showed that continuous clopidogrel treatment does not negatively affect osseointegration, but rather promotes it in terms of BIC and bone density around the titanium implants. Further studies on the effect of the P2Y12 receptor and its antagonists on peri-implant bone homeostasis may provide useful information or applications for long-term success of dental implant therapy.

Pure titanium (Ti) is investigated in a pre-clinical study in Hank\'s biological solution using electrochemical methods, open circuit potential, and electrochemical impedance spectroscopy to highlight the time effect in extreme body conditions, such as inflammatory diseases, on degradability due to corrosion processes occurring on the titanium implant. Electrochemical impedance spectroscopy (EIS) data are presented as Nyquist and Bode plots. The results show the increasing reactivity of titanium implants in the presence of hydrogen peroxide, which is an oxygen-reactive compound that describes inflammatory conditions. The polarization resistance, which results from electrochemical impedance spectroscopy measurements, declined dramatically from the highest value registered in Hank\'s solution to smaller values registered in all solutions when different concentrations of hydrogen peroxide were tested. The EIS analysis provided insights into titanium\'s in vitro corrosion behavior as an implanted biomaterial, which could not be solely obtained through potentiodynamic polarization testing.

Dental implants are artificial dental roots anchoring prosthetic restorations to replace natural teeth. Dental implant systems may have different tapered conical connections. Our research focused on the mechanical examination of implant-superstructure connections. Thirty-five samples with 5 different cone angles (24°, 35°, 55°, 75°, and 90°) were tested for static and dynamic loads, carried out by a mechanical fatigue testing machine. Fixing screws were fixed with a torque of 35 Ncm before measurements. For static loading, samples were loaded with a force of 500 N in 20 s. For dynamic loading, the samples were loaded for 15,000 cycles with a force of 250 ± 150 N. In both cases, the compression resulting from load and reverse torque was examined. At the highest compression load of the static tests, a significant difference (p = 0.021) was found for each cone angle group. Following dynamic loading, significant differences (p < 0.001) for the reverse torques of the fixing screw were also shown. Static and dynamic results showed a similar trend: under the same loading conditions, changing the cone angle-which determines the relationship between the implant and the abutment-had led to significant differences in the loosening of the fixing screw. In conclusion, the greater the angle of the implant-superstructure connection, the smaller the screw loosening due to loading, which may have considerable effects on the long-term, safe operation of the dental prosthesis.

The paper presents the optimization of diode laser irradiation of corroded dental implants in order to reduce the number of microorganisms associated peri-implantitis. The research included the identification of microorganisms on the surface of removed dental implants in patients with peri-implantitis and the assessment of the biocidal effectiveness of the diode laser against these microorganisms. Laser desorption/mass spectrometry (MALDI-TOF MS) was used to identify microorganisms and metagens were examined by next generation sequencing (NGS). Irradiation was performed with a diode laser with a wavelength of λ = 810, operating mode: 25 W/15.000 Hz/10 μs, average = 3.84 W with the number of repetitions t = 2 × 15 s and t = 3 × 15 s. The structure and surface roughness of the implants were analysed before and after laser irradiation by optical profilometry and optical microscopy with confocal fixation. In total, 16 species of Gram-positive bacteria and 23 species of Gram-negative bacteria were identified on the surface of the implants. A total of 25 species of anaerobic bacteria and 12 species with corrosive potential were detected. After diode laser irradiation, the reduction in bacteria on the implants ranged from 88.85% to 100%, and the reduction in fungi from 87.75% to 96.77%. The reduction in microorganisms in the abutment was greater than in the endosseous fixture. The applied laser doses did not damage, but only cleaned the surface of the titanium implants. After 8 years of embedding, the removed titanium implant showed greater roughness than the 25-year-old implant, which was not exposed to direct influence of the oral cavity environment. The use of a diode laser in an optimised irradiation dose safely reduces the number of microorganisms identified on corroded dental implants in patients with peri-implantitis.

The surface of titanium (Ti) dental implants must be modified to improve their applicability, owing to the biological inertness of Ti. This study aims to use sandblasting as a pretreatment method and prepare a hydroxyapatite (HA) coating on Ti to improve its biocompatibility and induce bone bonding and osteogenesis. In this paper, sandblasted Ti discs were coated with α-tricalcium phosphate (α-TCP) via Er:YAG pulsed laser deposition (Er:YAG-PLD). An HA coating was then obtained via the hydrothermal treatment of the discs at 90 °C for 10 h. The surface characteristics of the samples were evaluated by SEM, SPM, XPS, XRD, FTIR, and tensile tests. Rat bone marrow mesenchymal stem cells were seeded on the HA-coated discs to determine cellular responses in vitro. The surface characterization results indicated the successful transformation of the HA coating with a nanorod-like morphology, and its surface roughness increased. In vitro experiments revealed increased cell attachment on the HA-coated discs, as did the cell morphology of fluorescence staining and SEM analysis; in contrast, there was no increase in cell proliferation. This study confirms that Er:YAG-PLD could be used as an implant surface-modification technique to prepare HA coatings with a nanorod-like morphology on Ti discs.

Storage in aqueous solution or ultraviolet (UV) irradiation can retain or regain the hydrophilicity of titanium implant surface. In this study, 3 types of commercial titanium implants were used: ZBL (ZDI Bone Level), CEL (C-tech Esthetic Line), and modSLA (Straumann SLActive). ZBL and CEL implants were treated with UV irradiation for 4 hours. Surface characterization of the 4 groups (ZBL, ZBL-UV, CEL-UV, and modSLA) was evaluated by scanning electron microscopy and contact angle measurements. The in vivo bone response was evaluated by removal torque (RTQ) tests and histomorphometric analysis at 3, 6, and 12 weeks postimplantation. A total of 144 implants and 36 rabbits were used for experiments according to a previously established randomization sequence. The ZBL-UV, CEL-UV, and modSLA groups were hydrophilic, and nanostructures were observed on the modSLA implant surface. ModSLA achieved better RTQ value than ZBL at 12 weeks (P < .05). For histomorphometric analysis, ZBL-UV and CEL-UV implants showed higher bone area values in the cancellous bone zone at 6 weeks than did modSLA and ZBL implants (P < .05). In the cortical bone zone, all groups showed comparable bone-to-implant contact at all healing time points (P > .05). Both storage in saline and UV irradiation could retain or provoke hydrophilic surfaces and improve osseointegration. Compared with storage in saline, UV irradiation displayed slight advantages in promoting new bone formation in cancellous bone zone at an early stage.

To investigate the role of macrophages in the osseointegration of dental implants through induced macrophage reduction in a murine model. Fifty-four Sprague-Dawley rats with bilateral maxillary first molars replaced by titanium implants were randomly assigned into three groups. For the test group, macrophages were depleted by tail-vein injection of clodronate liposome (20 mg/kg) 3 days before implantation and reinjection every 3 days until the sacrifice of the rats (10 mg/kg). Animals treated with Phosphate Buffer saline (PBS) alone or empty liposome were included as controls. Samples contained implants were retrieved after 3, 7, 14, and 28 days, and the alterations of macrophages (CD68) and osteoblasts (Osterix) were evaluated using histology and immunohistochemistry technique. Histological analysis showed that new bone gradually formed within the lateral chamber regions in both the Control group and the Lip group, whereas bone healing was delayed at the first 2-weeks despite of pronounced newly formed peri-implant bone at 4 weeks in the Lipclod group. The bone-to-implant contact was significantly higher in the Lip and Control group than in the Lipclod group after 2 weeks. Immunohistochemical analysis showed that CD68+ cells were present both in the central region and in direct contact with implant surface throughout the healing period. Macrophages depletion reduced osteoblast amounts and new bone formation around implants in the first 2 weeks, and have no adverse impacts on the final formation of osseointegration. Macrophages play a dual role in both regulating the bone healing process and immune response to implant installation during the early stages.

A titanium implant surface when coated with biodegradable, highly porous, osteogenic nanofibrous coating has shown enhanced intrinsic osteoinductive and osteoconductive properties. This coating mimics extracellular matrix resulting in differentiation of stem cells present in the peri-implant niche to osteoblast and hence results in enhanced osseointegration of the implant. The osteogenic nanofibrous coating (ONFC) consists of poly-caprolactone, gelatin, nano-sized hydroxyapatite, dexamethasone, ascorbic acid and beta-glycerophosphate. ONFC exhibits optimum mechanical properties to support mesenchymal stem cells and steer their osteogenic differentiation. ONFC was subjected to various characterization tests like scanning electron microscopy, Fourier-transform infrared spectroscopy, x-ray diffractometry, thermal degradation, biomineralization, mechanical properties, wettability and proliferation assay. In pre-clinical animal trials, the coated implant showed enhanced new bone formation when placed in the tibia of rabbit. This novel approach toward implant bone integration holds significant promise for its easy and economical coating thus marking the beginning of new era of electrospun osteogenic nanofibrous coated bone implants.