Bone-to-implant Contact Research Articles

Histomorphometric analysis of implant osseointegration using hydrophilic implants in diabetic rats.

To evaluate peri-implant bone formation of titanium implants using an in vivo rat model with and without uncontrolled diabetes mellitus (DM) to evaluate osseointegration of hydrophobic (Neoporos®) and hydrophilic (Acqua®) surfaces. 54 rats were divided into two groups: DM group (DMG) (streptozotocin-induced diabetes) and a control group (CG). Implants with hydrophobic (Neoporos®) and hydrophilic surfaces (Acqua®) were placed in the left or right tibia of animals. Animals were further divided into three groups (n = 9) euthanized after 7, 14, or 28 days. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were assessed in total, cortical, and medullary areas. The DMG group, after a 7-day healing period, yielded with the Acqua implants presented significantly higher total BIC (+37.9%; p=0.03) and trabecular BIC (%) (+46.3%; p=0.02) values in comparison to the Neoporos implants. After 28 days of healing, the CG yielded that the cortical BAFO of Acqua implants to be significantly, 14%, higher (p=0.04) than Neoporos implants. The positive effects of the Acqua surface were able to counteract the adverse impact of uncontrolled DM at early osseointegration periods. After 28 days in vivo, the metabolic systemic impairment caused by DM overcame the surface treatment effect, leading to impaired osseointegration in both hydrophilic and hydrophobic implants. The adverse effects of diabetes mellitus with respect to bone healing may be minimized by deploying implants with strategically modified surfaces. This study evaluated the effects of implants with Acqua® and Neoporos® surfaces in both diabetic and healthy animals. During the initial healing period in diabetic animals, the hydrophilic surface was demonstrated to have beneficial effect on osseointegration in comparison to the hydrophobic surface. The results provide an insight into early healing, but the authors suggest that a future short-term and long-term clinical study is needed to assess the possible benefit of the Acqua® implant as well as in increasing the predictability of implant osseointegration.

Histomorphometric assessment of implant coated with mixture of nano-alumina and fluorapatite in rabbits

BackgroundThe application of nanoscale surface modification was found to be useful in the improvement of osseointegration of endosseous dental implants. The fluorapatite (FA)/alumina (Al2O3) mixture is recognized for its outstanding bioinertia and can significantly increase the biocompatibility and bioactivity of biomaterials. ObjectiveThe aim of the present work was to evaluate the bone response to nano-alumina- and fluorapatite-coated dental implants using rabbit tibiae. Material and MethodsThe coating was performed using the dip-coating method. Commercially pure titanium screw-type implants were used as a control group. The coated implants were the experimental group. Each group consisted of 12 screws that were surgically implanted in 6 healthy New Zealand rabbits. Histological and histomorphometric evaluations were performed at the bone to implant contact (BIC) interface, bone fraction area occupancy (BAFO) and fibrous tissue at 2 and 6 weeks of healing. ResultsThis analysis showed that the coated implants had more rapid osseointegration than the control group, with a significant difference after 2 and 6 weeks of healing for both groups. The histomorphometric evaluation demonstrated higher values for BIC% and BAFO% and lower values of fibrous tissue in the mixture-coated Ti implants than in the control group. ConclusionThe current study suggested that the nano-alumina and fluorapatite mixture coating is a favourable candidate for rapid osseointegration over uncoated implants.

The Effectiveness of Osseodensification Drilling Protocol for Implant Site Osteotomy: A Systematic Review of the Literature and Meta-Analysis.

Many different osteotomy procedures has been proposed in the literature for dental implant site preparation. The osseodensification is a drilling technique that has been proposed to improve the local bone quality and implant stability in poor density alveolar ridges. This technique determines an expansion of the implant site by increasing the density of the adjacent bone. The aim of the present investigation was to evaluate the effectiveness of the osseodensification technique for implant site preparation through a literature review and meta-analysis. The database electronic research was performed on PubMed (Medline) database for the screening of the scientific papers. A total of 16 articles have been identified suitable for the review and qualitative analysis—11 clinical studies (eight on animals, three on human subjects), four literature reviews, and one case report. The meta-analysis was performed to compare the bone-to-implant contact % (BIC), bone area fraction occupied % (BAFO), and insertion torque of clockwise and counter-clockwise osseodensification procedure in animal studies. The included articles reported a significant increase in the insertion torque of the implants positioned through the osseodensification protocol compared to the conventional drilling technique. Advantages of this new technique are important above all when the patient has a strong missing and/or low quantity of bone tissue. The data collected until the drafting of this paper detect an improvement when the osseodensification has been adopted if compared to the conventional technique. A significant difference in BIC and insertion torque between the clockwise and counter-clockwise osseodensification procedure was reported, with no difference in BAFO measurements between the two approaches. The effectiveness of the present study demonstrated that the osseodensification drilling protocol is a useful technique to obtain increased implant insertion torque and bone to implant contact (BIC) in vivo. Further randomized clinical studies are required to confirm these pieces of evidence in human studies.

Cellular and Molecular Dynamics during Early Oral Osseointegration: A Comprehensive Characterization in the Lewis Rat.

There is a need to improve the predictability of osseointegration in implant dentistry. Current literature uses a variety of in vivo titanium (Ti) implantation models to investigate failure modes and test new materials and surfaces. However, these models produce a variety of results, making comparison across studies difficult. The purpose of this study is to validate an oral osseointegration in the Lewis rat to provide a reproducible baseline to track the inflammatory response and healing of Ti implants. Ti screws (0.76 mm Ø × 2 mm length) were implanted into the maxillary diastema of 52 adult male Lewis rats. Peri-implant tissues were evaluated 2, 7, 14, and 30 days after implantation (n = 13). Seven of the 13 samples underwent microtomographic analysis, histology, histomorphometry, and immunohistochemistry to track healing parameters. The remaining six samples underwent quantitative polymerase chain reaction (qPCR) to evaluate gene expression of inflammation and bone remodeling markers over time. This model achieved a 78.5% success rate. Successful implants had a bone to implant contact (BIC)% of 68.86 ± 3.15 at 30 days on average. Histologically, healing was similar to other rodent models: hematoma and acute inflammation at 2 days, initial bone formation at 7, advanced bone formation and remodeling at 14, and bone maturation at 30. qPCR indicated the highest expression of bone remodeling and inflammatory markers 2-7 days, before slowly declining to nonsurgery control levels at 14-30 days. This model combines cost-effectiveness and simplicity of a rodent model, while maximizing BIC, making it an excellent candidate for evaluation of new surfaces.

An alternative ex vivo method to evaluate the osseointegration of Ti–6Al–4V alloy also combined with collagen

Due to the increasing number of orthopedic implantation surgery and advancements in biomaterial manufacturing, chemistry and topography, there is an increasing need of reliable and rapid methods for the preclinical investigation of osseointegration and bone ingrowth. Implant surface composition and topography increase osteogenicity, osteoinductivity, osteoconductivity and osseointegration of a prosthesis. Among the biomaterials used to manufacture an orthopedic prosthesis, titanium alloy (Ti–6Al–4V) is the most used. Type I collagen (COLL I) induces cell function, adhesion, differentiation and bone extracellular matrix component secretion and it is reported to improve osseointegration if immobilized on the alloy surface. The aim of the present study was to evaluate the feasibility of an alternative ex vivo model, developed by culturing rabbit cortical bone segments with Ti–6Al–4V alloy cylinders (Ti-POR), fabricated through the process of electron beam melting (EBM), to evaluate osseointegration. In addition, a comparison was made with Ti-POR coated with COLL I (Ti-POR-COLL) to evaluate osseointegration in terms of bone-to-implant contact (BIC) and new bone formation (nBAr/TAr) at 30, 60 and 90 d of culture. After 30 and 60 d of culture, BIC and nBAr/TAr resulted significantly higher in Ti-POR-COLL implants than in Ti-POR. No differences have been found at 90 d of culture. With the developed model it was possible to distinguish the biomaterial properties and behavior. This study defined and confirmed for the first time the validity of the alternative ex vivo method to evaluate osseointegration and that COLL I improves osseointegration and bone growth of Ti–6Al–4V fabricated through EBM.

Effects of low-dose aspirin on the osseointegration process in rats

BackgroundSeveral drugs are capable of promoting changes in bone metabolism. The aim of this study was to evaluate the effect of long-term low-dose aspirin (LDA) therapy on implant osseointegration.MethodsMale Wistar rats were divided into 4 groups (n = 8/group) according to oral gavage solution received prior (42 days) to the implant surgery on the tibia. The control group was treated with saline solution for 7 (CG-7) and 28 (CG-28) days. The use of low-dose aspirin was performed in AG groups (6.75 mg/kg of aspirin) for 7 (AG-7) and 28 (AG-28) days. After experimental periods, histomorphometric evaluation of bone-to-implant contact (BIC) and the bone area between threads (BABT) was performed.ResultsReduced BIC values were detected in AG-7 (62.8% ± 17.1) group compared to AG-28 (91.9% ± 5.4), CG-7 (82.7% ± 15.2), and CG-28 (89.9% ± 9.7). BABT evaluation revealed lower values in AG-7 (70.9% ± 15.2) compared to AG-28 (95.4% ± 3.7) and CG-28 (87.1% ± 10.2) groups.ConclusionsThe treatment with low doses of aspirin promoted a discrete inhibitory effect in the early stages (7 days) of repair after implant placement, specifically in the bone deposition. However, these effects were not detected in the late stages (28 days), considering BIC and BABT parameters.

Hard tissue volumetric and soft tissue contour linear changes at implants with different surface characteristics after experimentally induced peri-implantitis: an experimental in vivo investigation.

To evaluate the hard tissue volumetric and soft tissue contour linear changes in implants with two different implant surface characteristics after a ligature-induced peri-implantitis. In eight beagle dogs, implants with the same size and diameter but distinct surface characteristics were placed in the healed mandibular sites. Test implants had an external monolayer of multi-phosphonate molecules (B+), while control implants were identical but without the phosphonate-rich surface. Once the implants were osseointegrated, oral hygiene was interrupted and peri-implantitis was induced by placing subgingival ligatures. After 16weeks, the ligatures were removed and peri-implantitis progressed spontaneously. Bone to implant contact (BIC) and bone loss (BL) were assessed three-dimensionally with Micro-Ct (μCT). Dental casts were optically scanned and the obtained digitalized standard tessellation language (STL) images were used to assess the soft tissue vertical and horizontal contour linear changes. Reduction of the three-dimensional BIC percentage during the induction and progression phases of the experimental peri-implantitis was similar for both the experimental and control implants, without statistically significant differences between them. Soft tissue analysis revealed for both implant groups an increase in horizontal dimension after the induction of peri-implantitis, followed by a decrease after the spontaneous progression period. In the vertical dimension, a soft tissue dehiscence was observed in both groups, being more pronounced at the buccal aspect. The added phosphonate-rich surface did not provide a more resistant environment against experimental peri-implantitis, when assessed by the changes in bone volume and soft tissue contours. Ligature-induced peri-implantitis is a validated model to study the tissue changes occurring during peri-implantitis. It was hypothesized that a stronger osseointegration mediated by the chemical bond of a phosphonate-rich implant surface would develop an environment more resistant to the inflammatory changes occurring after experimental peri-implantitis. These results, however, indicate that the hard and soft tissue destructive changes occurring at both the induction and progression phases of experimental peri-implantitis were not influenced by the quality of osseointegration.

Effects of ibuprofen-loaded TiO₂ nanotube dental implants in alloxan-induced diabetic rabbits.

PurposeSome systemic conditions, especially diabetes mellitus (DM), adversely affect dental implant success. This study aimed to investigate the effects of ibuprofen-loaded TiO2 nanotube (ILTN) dental implants in alloxan-induced diabetic rabbits.MethodsTwenty-six New Zealand white rabbits were treated with alloxan monohydrate to induce DM. At 2 weeks following DM induction, 3 types of implants (sandblasted, large-grit, and acid-etched [SLA], ILTN, and machined) were placed into the proximal tibia in the 10 rabbits that survived following DM induction. Each type of implant was fitted randomly in 1 of the holes (round-robin method). The animals were administered alizarin (at 3 weeks) and calcein (at 6 weeks) as fluorescent bone markers, and were sacrificed at 8 weeks for radiographic and histomorphometric analyses.ResultsTiO2 nanotube arrays of ~70 nm in diameter and ~17 μm in thickness were obtained, and ibuprofen was loaded into the TiO2 nanotube arrays. A total of 26 rabbits were treated with alloxan monohydrate and only 10 rabbits survived. The 10 surviving rabbits showed a blood glucose level of 300 mg/dL or higher, and the implants were placed in these diabetic rabbits. The implant stability quotient (ISQ) and bone-to-implant contact (BIC) values were significantly higher in the ILTN group (ISQ: 61.8, BIC: 41.3%) and SLA group (ISQ: 62.6, BIC: 46.3%) than in the machined group (ISQ: 53.4, BIC: 20.2%), but the difference in the BIC percentage between the SLA and ILTN groups was not statistically significant (P=0.628). However, the bone area percentage was significantly higher in the ILTN group (78.0%) than in the SLA group (52.1%; P=0.000).ConclusionsThe ILTN dental implants showed better stability (ISQ) and BIC than the machined implants; however, these values were similar to the commercially used SLA implants in the 2-week diabetic rabbit model.

The Bone Buttress Theory: The Effect of the Mechanical Loading of Bone on the Osseointegration of Dental Implants.

Simple SummaryThe bone, as a vertebrate support tissue, is capable of adapting its structure and function to the mechanical demands resulting from the loads that are produced during the performance of its activity. This regulatory action also occurs during the healing processes of a fracture. The purpose of this study was to determine to what extent a dynamic load was capable of modulating the bone healing response around a titanium implant. The study was carried out on experimental rabbits, to which dental implants were placed in the tibiae and there were two test groups, one in which they did not undergo exercise during healing period and another that ran daily during this process on a treadmill. The trail results showed an improvement in the osseointegration process of the implant in the group in which it was subjected to load. The importance of these results is that it opens the door to a better understanding of the mechanisms that can modulate bone healing, especially around dental implants, supporting implant loading protocols that are based on efficiency.Objectives: To determine the effect of mechanical loading of bone on the stability and histomorphometric variables of the osseointegration of dental implants using an experimental test in an animal model. Materials and Methods: A total of 4 human implants were placed in both tibiae of 10 New Zealand rabbits (n = 40). A 6-week osseointegration was considered, and the rabbits were randomly assigned to two groups: Group A (Test group) included 5 rabbits that ran on a treadmill for 20 min daily during the osseointegration period; Group B (Controls) included the other 5 that were housed conventionally. The monitored variables were related to the primary and secondary stability of the dental implants (implant stability quotient—ISQ), vertical bone growth, bone to implant contact (BIC), area of regenerated bone and the percentage of immature matrix. Results: The results of the study show a greater vertical bone growth (Group A 1.26 ± 0.48 mm, Group B 0.32 ± 0.47 mm, p < 0.001), higher ISQ values (Group A 11.25 ± 6.10 ISQ, 15.73%; Group B 5.80 ± 5.97 ISQ, 7.99%, p = 0.006) and a higher BIC (Group A 19.37%, Group B 23.60%, p = 0.0058) for implants in the test group, with statistically significant differences. A higher percentage of immature bone matrix was observed for implants in the control group (20.68 ± 9.53) than those in the test group (15.38 ± 8.84) (p = 0.108). A larger area of regenerated bone was also observed for the test implants (Group A 280.50 ± 125.40 mm2, Group B 228.00 ± 141.40 mm2), but it was not statistically significant (p = 0.121). Conclusions: The mechanical loading of bone improves the stability and the histomorphometric variables of the osseointegration of dental implants.

Hydrophilic titanium surface modulates early stages of osseointegration in osteoporosis.

Using a mouse osteoporotic model, this study aimed to determine the influence of hydrophilic titanium surfaces on gene expression and bone formation during the osseointegration process. Based on the previous evidence, it is plausible to assume that osteoporotic bone has a different potential of bone healing. Therefore, implant surface modification study that aims at enhancing bone formation to further improve short- and long-term clinical outcomes in osteoporosis is necessary. Fifty female, 3-month-old mice were included in this study. Osteoporosis was induced by ovariectomy (OVX, test group) in 25 mice. The further 25 mice had ovaries exposed but not removed (SHAM, control group). Seven weeks following the ovariectomy procedures, one customized implant (0.7×8mm) of each surface was placed in each femur for both groups. Implants had either a hydrophobic surface (SAE) or a hydrophilic treatment surface (SAE-HD). Calcium (Ca) and phosphorus (P) content was measured by energy-dispersive X-ray spectroscopy (EDS) after 7days. The femurs were analyzed for bone-to-implant contact (BIC) and bone volume fraction (BV) by nano-computed tomography (nano-CT) after 14 and 28days. Same specimens were further submitted to histological analysis. Additionally, after 3 and 7days, implants were removed and cells were collected around the implant to access gene expression profile of key osteogenic (Runx2, Alp, Sp7, Bsp, Sost, Ocn) and inflammatory genes (IL-1β, IL-10, Tnf-α, and Nos2) by qRT-PCR assay. Statistical analysis was performed by ANOVA and paired t test with significance at P<.05. The amount of Ca and P deposited on the surface due to the mineralization process was higher for SAE-HD compared to SAE on the intra-group analysis. Nano-CT and histology revealed more BV and BIC for SAE-HD in SHAM and OVX groups compared to SAE. Analysis in OVX group showed that most genes (ie, ALP, Runx2) involved in the bone morphogenetic protein (BMP) signaling were significantly activated in the hydrophilic treatment. Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a faster response in terms of bone formation and osteogenic gene expression compared to SAE. Hydrophilic surface in situations of osteoporosis seems to provide additional benefits in the early stages of osseointegration.

Osseointegration of additive manufacturing Ti–6Al–4V and Co–Cr–Mo alloys, with and without surface functionalization with hydroxyapatite and type I collagen

The introduction of additive manufacturing (AM) technologies has profoundly revolutionized the implant manufacturing industry, with a particularly significant impact on the field of orthopedics. Electron Beam Melting (EBM) and Direct Metal Laser Sintering (DMLS) represents AM fabrication techniques with a pivotal role in the realization of complex and innovative structure starting from virtual 3D model data. In this study, Ti–6Al–4V and Co–Cr–Mo materials, developed by EBM (Ti-POR) and DMLS (Co-POR) techniques, respectively, with hydroxyapatite (Ti-POR + HA; Co-POR + HA) and type I collagen (Ti-POR-COLL; Co-POR-COLL) coatings, were implanted into lateral femoral condyles of rabbits. Osseointegration process was investigated by histological, histomorphometrical and microhardness evaluations at 4 and 12 weeks after implantation. Both Ti–6Al–4V and Co–Cr–Mo implants, with or without HA and COLL coatings, demonstrated good biocompatibility. As expected, HA coating hastened bone-to-implant contact (BIC) process, while collagen did not significantly improved the osseointegration process in comparison to controls. Regarding newly trabecular bone formation (B.Ar/T.Ar), Co-POR presented the highest values, significantly different from those of Co-POR-COLL. Over time, an increase of BIC parameter and a decrease of B.Ar/T.Ar were detected. Higher mineral apposition rate was observed for Ti-POR and Co-POR in comparison to Ti-POR-COLL and Co-POR-COLL, respectively, at 12 weeks. The same behavior was found for bone formation rate between Co-POR and Co-POR-COLL at 12 weeks. In conclusion, the AM materials guarantee a good osseointegration and provide a suitable environment for bone regeneration with the peculiarity of allowing personalized and patient-specific needs customization to further improve the long-term clinical outcomes.

Effects of surface sub-micrometer topography following oxalic acid treatment on bone quantity and quality around dental implants in rabbit tibiae

BackgroundTo explore the effects of topographical modification of titanium substrates at submicron level by oxalic acid treatment on bone quality and quantity around dental implants in rabbit tibiae.MethodsA total of 60 blasted CP-grade IV titanium dental implants were used. Twenty-eight control implant surfaces were treated with a mixture of HCl/H2SO4, whereas 28 other test implant surfaces were treated with oxalic acid following HCl/H2SO4 treatment. Two randomly selected sets of control or test implants were placed in randomly selected proximal tibiae of 14 female Japanese white rabbits. Euthanasia was performed 4 and 8 weeks post-implant placement. Bone to implant contact (BIC), bone area fraction (BAF), ratios of mature and immature bone to total bone, and the amount and types of collagen fibers were evaluated quantitatively. Two control and two test implants were used to analyze surface characteristics.ResultsTreatment by oxalic acid significantly decreased Sa and increased Ra of test implant surfaces. BIC in test implants was increased without alteration of BAF and collagen contents at 4 and 8 weeks after implant placement when compared with control implants. The ratios of immature and mature bone to total bone differed significantly between groups at 4 weeks post-implantation. Treatment by oxalic acid increased type I collagen and decreased type III collagen in bone matrices around test implants when compared with control implants at 8 weeks after implant placement. The effects of topographical changes of implant surfaces induced by oxalic acid on BAF, mature bone, collagen contents, and type I collagen were significantly promoted with decreased immature bone formation and type III collagen in the later 4 weeks post-implantation.ConclusionsTreatment of implant surfaces with oxalic acid rapidly increases osseointegration from the early stages after implantation. Moreover, submicron topographical changes of dental implants induced by oxalic acid improve bone quality based on bone maturation and increased production of type I collagen surrounding dental implants in the late stage after implant placement.

In-vivo comparison of the Ni-free steel X13CrMnMoN18-14-3 and titanium alloy implants in rabbit femora - A promising steel for orthopedic surgery.

A variety of metallic biomaterials is used for fracture fixation. Allergic reactions towards nickel-containing steels urge the need for alternatives. The present study investigated the suitability of the nickel-free stainless steel P2000 in comparison to titanium alloy implants for bone surgical applications in a rabbit femora defect model. Thirty-six rabbits received two different cylindrical implants press-fit inserted into the distal femoral metaphysis. At day 0, 28, and 56, implant ingrowth was monitored by radiography; implant stability was assessed by pull-out torque measurements while bone-to-implant contact (BIC) was determined histomorphometrically. Radiography revealed comparable implant ingrowth after 1 and 2 months for both implant materials. The pull-out force of P2000 tended to be higher than that for titanium at day 28 (p = .076) but the values were comparable at day 56 (p = .905). At day 56, implant fixation was significantly increased compared to the day of surgery for both, P2000 (p = .030) and for titanium alloy (p = .026). Microscopic examination revealed that both implant types appeared to be well integrated and firmly anchored in the bone. BIC ratio of titanium alloy tended to be higher at day 28 (p = .079) but they did not differ significantly at day 56 (p = .711). In the present rabbit femora defect model, the nickel-free stainless steel P2000 provides primary stability and osseointegration comparable to that of titanium alloy implants.

A Novel Xenograft Bone Substitute Supports Stable Bone Formation in Circumferential Defects Around Dental Implants in Minipigs.

The aim of this study was to evaluate and compare bone growth and implant integration in circumferential defects with two commercially available bone substitutes (demineralized bovine bone mineral [DBBM]). Circumferential defects were created in the mandibles of minipigs (n = 10), and Bone Level Tapered implants (Straumann Roxolid with SLActive surface) were placed. The defects (4-mm-deep circumferential defect, 2 mm around each implant) were augmented with either sintered bovine bone mineral (test, cerabone) or natural bovine bone mineral (control, Bio-Oss). Bone formation and tissue composition in augmented sites were histomorphometrically assessed after 8 and 12 weeks of healing time (n = 5 each), respectively, in terms of the percentage of area of newly formed bone to total area, bone-to-implant contact (BIC), and crestal bone height relative to the implant shoulder (first bone-to-implant contact [fBIC]). Bone formation in all defect sites was adequate and equivalent for both groups at individual healing time points. The amount of residual graft material was comparable in both groups after 8 and 12 weeks, with no significant resorption in either group. The mean newly formed bone area in the test group amounted to 46.7% ± 5.1% and 48.7% ± 4.0% after 8 and 12 weeks vs 47.0% ± 4.8% and 47.8% ± 7.3% in the control group, respectively. BIC and fBIC as individually assessed for the lingual and buccal aspects were comparable at both healing time points without any statistically significant differences between the groups. A slightly greater variability of fBIC was observed within the test group. The results of this study indicate that test and control materials both represent viable bovine bone graft material that equivalently support the formation of new and stable bone volume specifically when used for simultaneous augmentation around implants.

Effects of the local administration of antibiotics on bone formation on implant surface in animal models: A systematic review and meta-analysis.

SummaryPurposeThis review aimed to evaluate the effects of the local delivery of antibiotics incorporated in implant surfaces on some quantitative parameters of bone formation.Materials and methodsAn electronic search was undertaken in three databases (PubMed, Scopus, Embase) in addition to hand searching. The search was limited to animal experiments using endosseous implants combined with localized antibiotics release. Meta-analyses were performed for the percentages of bone volume (BV) and bone-to-implant contact (BIC).ResultsNine studies met the inclusion criteria. Several methods were identified for local delivery of antibiotics at the bone-implant interface, but the most commonly used method was by coating (incorporating the implant surface with the antibiotic agents). Different antibiotic agents were used, namely bacitracin, doxycycline, enoxacin, gentamicin, minocycline, tobramycin, and vancomycin. There was no statistically significant difference in the percentage of BIC between implants with or without localized antibiotic release (P = 0.59). The meta-analysis revealed higher BV around implants coated with antibiotics compared to control groups (without antibiotics) (P < 0.01).ConclusionIt is suggested that the local administration of antibiotics around implants did not adversely affect the percentage of direct bone contact around implants, with a tendency for a slightly better bone formation around implants when combined with local administration of antibiotics. It is a matter of debate whether these in vivo results will have the same effect in the clinical setting. However, the risk of bias of these studies may, to some extent, question the validity of these results.

Comparison of 3D-Printed Dental Implants with Threaded Implants for Osseointegration: An Experimental Pilot Study.

This study aimed to compare bone healing and implant stability for three types of dental implants: a threaded implant, a three-dimensional (3D)-printed implant without spikes, and a 3D-printed implant with spikes. In four beagle dogs, left and right mandibular premolars (2nd, 3rd, and 4th) and 1st molars were removed. Twelve weeks later, three types of titanium implants (threaded implant, 3D-printed implant without spikes, and 3D-printed implant with spikes) were randomly inserted into the edentulous ridges of each dog. Implant stability measurements and radiographic recordings were taken every two weeks following implant placement. Twelve weeks after implant surgery, the dogs were sacrificed and bone-to-implant contact (BIC) and bone area fraction occupied (BAFO) were compared between groups. At implant surgery, the primary stability was lower for the 3D-printed implant with spikes (74.05 ± 5.61) than for the threaded implant (83.71 ± 2.90) (p = 0.005). Afterwards, no significant difference in implants’ stability was observed between groups up to post-surgery week 12. Histomorphometrical analysis did not reveal a significant difference between the three implants for BIC (p = 0.101) or BAFO (p = 0.288). Within the limits of this study, 3D-printed implants without spikes and threaded implants showed comparable implant stability measurements, BIC, and BAFO.

A pilot animal study aimed at assessing the mechanical quality of regenerated alveolar bone

Purpose Bone regeneration procedures are often evaluated based on biologic aspects only. As regenerated bone also has to ensure primary implant stability, the goal of this study was to determine the mechanical quality of regenerated bone. Materials and methods Six adult minipigs were allocated for this experiment with four mandibular study sites each established following tooth removal. Two different types of bovine bone mineral as well as autogenous bone were used for augmenting three-walled defects, while native bone served as the control. Implants were placed after 12, 18, and 24 weeks of healing, and bone quality was determined using intraoperative compressive testing (BoneProbe), insertion torque measurements, and resonance frequency analysis. The mandibles were then harvested for determining bone mineral density (BMD) and bone-to-implant contact (BIC). Statistical analysis was based on two-way analysis of variance of aligned rank transformed data and Spearman's rank correlation tests (α = .05). Results The effects of the factors healing time and material on the parameters tested were too small to be significant (P ranging from .34 to .98). Weak correlations were observed for implant insertion torque with BoneProbe measurements in the cortical (0.481; P = .032) and in the trabecular area (0.639; P = .002). BoneProbe measurements in the trabecular part and in the cortical part also correlated with each other (0.477; P = .035). Conclusion While differences may exist between bone regenerated using different biomaterials with respect to biologic behavior, differences in the mechanical properties determining primary implant stability seem to be minor. Implant insertion torque measurements appear to be a reliable tool for determining bone quality if only one specific implant type is considered.

Osseointegration of a novel injection molded 2-piece ceramic dental implant: a study in minipigs.

This study compared the osseointegrative potential of a novel injection molded zirconia dental implant (Neodent Zi ceramic implant, test) and a commercially available titanium implant (Neodent Alvim implant, control) in terms of histomorphometrically derived bone-to-implant contact (BIC), first bone-to-implant contact (fBIC), and the ratio of bone area to total area (BATA) around the implant. A total of 36 implants, 18 per individual test device, were implanted in a split-mouth arrangement in either side of the edentulous and fully healed mandible of 6 minipigs. Histomorphometric analysis of BIC, fBIC, and BATA were performed 8 weeks post implantation and subjected to statistical non-inferiority testing. Surface characteristics of both implant types were compared in terms of contact angle, surface topography, and elemental composition. BIC, fBIC, and coronal BATA values of test and control implants were statistically comparable and non-inferior. BIC values of 77.8 ± 6.9% vs. 80.7 ± 6.9% (p = 0.095) were measured for the test and control groups. fBIC lingual values were - 238 ± 328 μm compared with - 414 ± 511 μm (p = 0.121) while buccal values were - 429 ± 648 μm and - 588 ± 550 μm (p = 0.230) for the test and control devices, respectively. BATA in the apical segment was significantly higher in the test group compared with the control group (67.2 ± 11.8% vs. 59.1 ± 11.4%) (p = 0.0103). Surface topographies of both implant types were comparable. Surface chemical analysis indicated the presence of carbonaceous adsorbates which correlated with a comparable and predominantly hydrophobic character of the implants. The results demonstrate that the investigated zirconia implants, when compared with a commercially available titanium implant, show equivalent and non-inferior bone integration, bone formation, and alveolar bone level maintenance. This qualifies the investigated zirconia implant as a potential candidate for clinical development. This study investigated the osseointegration of a novel zirconia 2-piece dental implant prototype intended for clinical development. With the aim of translating this prototype into clinical development preclinical models, procedures and materials within this study have been selected as close to clinical practice and human physiological conditions as possible.

Human Histologic Evaluations of Implants with a Unique Triangular Neck Design.

The goal of the present study was to evaluate human histologic healing of dental implants with a unique triangular neck design that is narrower than the implant body. Four patients in need of full-mouth reconstruction were recruited and received several implants to support a full-arch prosthesis. In each patient, two additional customized reduced-diameter implants were placed, designated to be harvested after 6 months of submerged healing. The eight harvested implants were all placed in healed edentulous maxillary or mandibular ridges. These implants were Ø 3.5 × 8 mm in size, and the final osteotomy drill allowed for the creation of a gap up to 0.2 mm in size between the coronal aspect of the triangular implant neck and the surrounding bone. At the end of the healing period, the implants were retrieved with the surrounding bone. Microcomputed tomography (μCT) was performed before processing the biopsy samples for undecalcified histologic exampination. Bone-to-implant contact (BIC) was measured from the μCT data and from buccolingual/buccopalatal and mesiodistal central histologic sections. All implant gaps were filled by mature remodeled bone. The mean BICs of the BL/BP and MD sections were 64.45% ± 6.86% and 65.39% ± 10.44%, respectively, with no statistically significant difference. The mean 360-degree 3D BIC measured all over the implant surface was 68.58% ± 3.76%. The difference between the BIC measured on the μCT and on the histologic sections was not statistically significant. The positive histologic results of the study confirmed the efficacy of this uniquely designed dental implant.

Comparison of bone-to-implant contact and bone volume around implants placed with or without site preparation: a histomorphometric study in rabbits

The objective of this in vivo study was to compare bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) values of a new implant, designed to be inserted without bone preparation, using two different preparation protocols: no site preparation and prior limited cortical perforation, versus the values of a control implant using a conventional drilling protocol. Forty-one implants were inserted in 13 rabbits. Thirteen test implants with a new thread design were inserted using no bone preparation (NP), 14 test implants were inserted with limited cortical perforation (CP), and 14 conventional implants served as control. Five animals were sacrificed after 21 days and eight animals after 42 days. Histomorphometric analysis was performed and percentage of BIC and BAFO values were measured. ANOVA with Tukey post hoc and Mann–Whitney nonparametric tests were calculated to compare between the groups. Statistical analysis showed no significant difference in the measured values between any of the groups, neither compered by implant nor by compered day. The results demonstrated that biological osseointegration parameters of implant that was inserted without any bone preparation was non-inferior compared to conventional preparation. The clinical relevance is that novel implant designs may not require bone preparation prior to placement.