Effects of implant design and surface on bone regeneration and implant stability: an experimental study in the dog mandible

Comparative Evaluation of Bone-Implant Contact in Various Surface-Treated Dental Implants Using High-Resolution Micro-CT in Rabbits' Bone

This study evaluated the bone-to-implant contact (BIC) of various surface-treated dental implants using high-resolution micro-CT in rabbit bone, focusing on the effects of different treatments on osseointegration and implant stability before and after bone demineralization. Six male New Zealand White rabbits were used. Four implant types were tested: machined surface with anodizing, only etching, sandblasting with Al2O3 + etching, and sandblasting with TiO2 + etching. Implants were scanned with high-resolution micro-CT before and after demineralization. Parameters like implant volume, surface area, and BIC were determined using specific software tools. During demineralization, the BIC changed about 6% for machined surface with anodizing, 5% for only etching, 4% for sandblasting with Al2O3 + etching, and 10% for sandblasting with TiO2 + etching. Demineralization reduced BIC percentages, notably in the machined surface with anodizing and sandblasting with TiO2 + etching groups. Etching and sandblasting combined with etching showed higher initial BIC compared to anodizing alone. Demineralization negatively impacted the BIC across all treatments. This study underscores the importance of surface modification in implant integration, especially in compromised bone. Further research with larger sample sizes and advanced techniques is recommended.

A Standardized Rat Model to Study Peri-implantitis of Transmucosal Osseointegrated Implants

With the high incidence rate, distinctive implant characteristic and unique infection pattern, peri-implantitis (PI) requires a specially designed implant animal model for the researches on the pathogenesis and treatments. Previous small-animal PI models exhibit variability in implant site selection, design, and surgical procedures resulting in unnecessary tissue damage and less effectivity. Herein, a quantitative-analysis-based standardized rat model for transmucosal PI-related research was proposed. After dissecting the anatomic structures of the rat maxilla, we determined that placing the implant anterior to the molars in the rat maxilla streamlined the experimental period and enhanced animal welfare. We standardized the model by controlling the rat strain, gender, and size. The customized implant and a series of matched surgical instruments were appropriately designed. A clear, step-by-step surgical process was established. These designs ensured the success rate, stability, and replicability of the model. Each validation method confirmed the successful construction of the model. This study proposed a quantitative-analysis-based standardized transmucosal PI rat model with improved animal welfare and reliable procedures. This model could provide efficient in vivo insights to study the pathogenesis and treatments of PI and preliminary screening data for further large-animal and clinical trials.

Efficacy of bone defect therapy involving various surface treatments of titanium alloy implants: an in vivo and in vitro study

Multiple surface treatment methods for titanium alloy prostheses, widely used in orthopedics, are available; however, these can affect bone integration and regeneration efficiency. In this study, through cell and animal experiments, we devised seven bone implant categories of Ti6Al4V based on surface preparation and post-processing technology (polishing, grit-blasting, fine titanium spraying, coarse titanium spraying, electron beam melting [EBM] printing, selective laser melting [SLM] printing, and post-processed SLM printing) and imaged each microscopic surface structure with a scanning electron microscope (SEM). Mechanical testing revealed excessive post-processing damaged the mechanical properties of the implants. In vitro, human bone marrow mesenchymal stem cells (hBMSCs) were cultured with implants, and the morphology of the cells adhering to the implant surface was observed using SEM and confocal laser scanning microscopy. Cell Counting Kit-8 (CCK-8) semi-quantitatively determined cell activity, indirectly reflecting the proliferation of hBMSCs. Alizarin red and alkaline phosphatase experiments assessed osteogenic differentiation. In vivo, experiments utilized the New Zealand rabbit femoral condyle bone defect model to assess bone regeneration and integration using micro-computed tomography, Van Giesen staining, and Masson staining. We found that 3D-printed implants with regular pore structures were more conducive to hBMSC osteogenic differentiation, while the presence of metal powder on NPT-SLM-printed implants hindered such differentiation. The post-treatment SLM scaffold surface may have some residual semi-melted powder; however, these powder residues have no significant effect on cell activity and differentiation. Surface treatment (grit-blasting and titanium spraying) of planar structures can enhance hBMSC adhesion but does not necessarily promote their differentiation. The framework structure of 3D printing may affect the osteogenic differentiation of hBMSCs, and for SLM-printed implants, excessive pursuit of a "powderless" state will damage the mechanical properties of the implant.

Effect of Microimplant Neck Design with and without Microthread on Pullout Strength and Destruction Volume

The microthread neck concept has been applied to dental implants. This study investigated the pullout strength and destruction volume of orthodontic microimplants with and without the microthread neck design. Fifteen microimplants (diameter: 1.5 × 10 mm) of three types (Types A and B: without microimplant neck; Type C: with microimplant neck) were tested. The insertion torque (IT), Periotest value (PTV), horizontal pullout strength (HPS), and horizontal destruction volume (HDV) of each type were measured. Kruskal–Wallis H test and Dunn’s post-hoc comparison test were performed to compare the measured values of the three types of microimplants. The correlations of the measured values were used to perform the Spearman’s correlation coefficient analysis. The ITs of Types B (8.8 Ncm) and C (8.9 Ncm) were significantly higher than those of Type A (5.2 Ncm). Type B yielded the lowest PTV (4.1), and no statistical differences in PTV were observed among the three types. Type A had a significantly lower HPS (158.8 Ncm) than Types B (226.9 Ncm) and C (212.8 Ncm). The three types did not exhibit any significant differences in the HDV. The results of the Spearman’s correlation coefficient test revealed that HDV (ρ = 0.710) and IT (ρ = 0.813) were strongly correlated with HPS, whereas for PTV and HPS, it was not. HPS was strongly and significantly correlated with HDV. The orthodontic microimplant with a microimplant neck design did not perform better than that without a microthread in the mechanical strength test.

Multi-Scale Surface Treatments of Titanium Implants for Rapid Osseointegration: A Review

The propose of this review was to summarize the advances in multi-scale surface technology of titanium implants to accelerate the osseointegration process. The several multi-scaled methods used for improving wettability, roughness, and bioactivity of implant surfaces are reviewed. In addition, macro-scale methods (e.g., 3D printing (3DP) and laser surface texturing (LST)), micro-scale (e.g., grit-blasting, acid-etching, and Sand-blasted, Large-grit, and Acid-etching (SLA)) and nano-scale methods (e.g., plasma-spraying and anodization) are also discussed, and these surfaces are known to have favorable properties in clinical applications. Functionalized coatings with organic and non-organic loadings suggest good prospects for the future of modern biotechnology. Nevertheless, because of high cost and low clinical validation, these partial coatings have not been commercially available so far. A large number of in vitro and in vivo investigations are necessary in order to obtain in-depth exploration about the efficiency of functional implant surfaces. The prospective titanium implants should possess the optimum chemistry, bionic characteristics, and standardized modern topographies to achieve rapid osseointegration.

Effect of Rough Surface Platforms on the Mucosal Attachment and the Marginal Bone Loss of Implants: A Dog Study

The preservation of peri-implant tissues is an important factor for implant success. This study aimed to assess the influence of the surface features of a butt-joint platform on soft-tissue attachment and bone resorption after immediate or delayed implant placement. All premolars and first molars of eight Beagle dogs were extracted on one mandible side. Twelve-weeks later, the same surgery was developed on the other side. Five implants with different platform surface configurations were randomly inserted into the post-extracted-sockets. On the healed side, the same five different implants were randomly placed. Implants were inserted 1 mm subcrestal to the buccal bony plate and were connected to abutments. The primary outcome variables were the supracrestal soft tissue (SST) adaptation and the bone resorption related to the implant shoulder. The SST height was significantly larger in immediate implants (IC95% 3.9–4.9 mm) compared to delayed implants (IC95% 3.1–3.5 mm). Marginal bone loss tended to be higher in immediate implants (IC95% 0.4–0.9 mm) than in delayed implants (IC95% 0.3–0.8 mm). Linear-regression analysis suggested that the SST height was significantly affected by the configuration of the platform (0.3–1.9 mm). Roughened surface platforms resulted in higher SST height when compared to machined surface platforms. Marginal bone loss was less pronounced in roughened designs.

Treatments for enhancing the biocompatibility of titanium implants

Titanium surface treatment is a crucial process for achieving sufficient osseointegration of an implant into the bone. If the implant does not heal sufficiently, serious complications may occur, e.g. infection, inflammation, aseptic loosening of the implant, or the stress-shielding effect, as a result of which the implant may need to be reoperated. After a titanium graft has been implanted, several interactions are crucial in order to create a strong bone-implant connection. It is essential that cells adhere to the surface of the implant. Surface roughness has a significant influence on cell adhesion, and also on improving and accelerating osseointegration. Other highly important factors are biocompatibility and resistance to bacterial contamination. Bio-inertness of titanium is ensured by the protective film of titanium oxides that forms spontaneously on its surface. This film prevents the penetration of metal compounds, and it is well-adhesive for calcium and phosphate ions, which are necessary for the formation of the mineralized bone structure. Since the presence of the film alone is not sufficient for the biocompatibility of titanium, a suitable surface finish is required to create a firm bone-implant connection. In this review, we explain and compare the most widely-used methods for modulating the surface roughness of titanium implants in order to enhance cell adhesion on the surface of the implant, e.g. plasma spraying, sandblasting, acid etching, laser treatment, sol-gel etc., The methods are divided into three overlapping groups, according to the type of modification.

The custom making of hierarchical micro/nanoscaled titanium phosphate coatings and their formation mechanism analysis

In this study, a series of hierarchical micro/nanoscaled titanium phosphate (TiP) coatings possessing various surface morphologies were successfully fabricated on titanium (Ti) discs. The hydrothermal reactions of Ti discs in hydrogen peroxide (H2O2) and phosphoric acid (H3PO4) mixed solution yield diverse topographies such as hemispheric clump, cylindrical rod, spherical walnut, micro/nano grass, micro/nano sheet, and fibrous network. And their crystal structures were mainly composed of Ti(HPO4)2·0.5H2O, (TiO)2P2O7, H2TiP2O8, Ti(HPO4)2 and TiO2. The morphology and crystal shape of the TiP coatings depend strongly on the mass ratio of H2O2/H3PO4, reaction temperature and water content. Besides, the formation mechanism of TiP coatings with diverse morphologies was explored from the perspective of energetics and crystallography. The mechanism exploration paved the way for custom-making TiP coatings with desirable micro/nanoscaled morphologies to meet specific application purposes. The in vitro cytological performances of TiP coatings were also evaluated by co-culturing with rat bone marrow stromal cells (BMSCs), demonstrating a positive prospect for their use in bone tissue engineering.

Maxillary sinus floor elevation using hydroxyapatite nano particles vs tenting technique with simultaneous implant placement: A randomized clinical trial

PURPOSE

The present study was conducted to evaluate the amount of bone height gain, density values, and implant stability after maxillary sinus floor elevation using graftless tenting technique or the use of Hydroxyapatite Nanoparticles bone substitute for augmentation with simultaneous implant placement.

MATERIALS AND METHODS

A total of 20 sinuses with a residual alveolar bone height ranging from 4-6 mm were divided into two groups and underwent sinus augmentation using nano hydroxyapatite bone substitute material and the graftless tenting technique with simultaneous implant placement. Computed tomography CT scans and ISQ measurements were conducted to evaluate bone quality, quantity, and implant stability.

RESULTS

Radiographic analysis revealed that the mean bone height gain of the nano group was (7.0 ± 0.8 mm) compared to (5.0 ± 1.5 mm) in the tent group, which was statistically significant (P = .002) being higher in the nano group. The mean bone density value of the nano group was (548 ± 25 HU) compared to (420 ± 23 HU) in the tent group, which was statistically significant (P < .001) being higher in the nano group. The mean ISQ value after 6 months in the nano group was (78 ± 5) compared to (77 ± 5) in the tent group, which was statistically nonsignificant (P = .901).

CONCLUSION

Nano hydroxyapatite bone graft offered superior results in terms of the bone height gain and the relative bone density as compared to graftless tenting technique. However, both techniques showed accepted results regarding implant stability.

The Effect of Ultraviolet Photofunctionalization on a Titanium Dental Implant with Machined Surface: An In Vitro and In Vivo Study

Ultraviolet (UV) photofunctionalization has been suggested as an effective method to enhance the osseointegration of titanium surface. In this study, machined surface treated with UV light (M + UV) was compared to sandblasted, large-grit, acid-etched (SLA) surface through in vitro and in vivo studies. Groups of titanium specimens were defined as machined (M), SLA, and M + UV for the disc type, and M + UV and SLA for the implant. The discs and implants were assessed using scanning electron microscopy, confocal laser scanning microscopy, electron spectroscopy for chemical analysis, and the contact angle. Additionally, we evaluated the cell attachment, proliferation assay, and real-time polymerase chain reaction for the MC3T3-E1 cells. In a rabbit tibia model, the implants were examined to evaluate the bone-to-implant contact ratio and the bone area. In the M + UV group, we observed the lower amount of carbon, a 0°-degree contact angle, and enhanced osteogenic cell activities (p < 0.05). The histomorphometric analysis showed that a higher bone-to-implant contact ratio was found in the M + UV implant at 10 days (p < 0.05). In conclusion, the UV photofunctionalization of a Ti dental implant with M surface attained earlier osseointegration than SLA.

Influence of a Novel Surface of Bioactive Implants on Osseointegration: A Comparative and Histomorfometric Correlation and Implant Stability Study in Minipigs

Purpose: The objective of this study was to assess the influence of a novel surface of dental implants (ContacTi^®) on the osseointegration process in a minipig model. The surface was compared with other existing surfaces on the market (SLA^® and SLActive^®) by employing bone implant contact analysis (BIC) and implant stability. Method: Twelve minipigs were used with prior authorisation from an ethics committee. Three types of surfaces were tested: SLA^® (sand-blasted acid-etched titanium), SLActive^® (same but hydrophilic, performed under a nitrogen atmosphere), and ContacTi^® (alumina particle bombardment of titanium, bioactivated when treated thermochemically) in 4.1 mm × 8 mm implants with internal connection and a polished neck. Twelve implants of each surface type (N = 36) were placed, sacrificing 1/3 of the animals at 2 weeks of placement, 1/3 at 4 weeks and the remaining 1/3 at 8 weeks. Numerical variables were compared with Analysis of Variance, and the correlation between ISQ and BIC was established with the Spearman’s rank correlation coefficient. Results: SLActive^® and ContacTi^® surfaces showed elevated osteoconductivity at 4 weeks, maintaining a similar evolution at 8 weeks (large amount of mature lamellar tissue with high maturity and bone quality). The SLA^® surface showed slower maturation. The ISQ values in surgery were elevated (above 65), higher at necropsy and higher at 4 and 8 weeks in the SLA^® group than in the other two (SLActive^® and ContacTi^®). No significant correlation was found between ISQ and BIC for each implant surface and necropsy time. Conclusion: The three surfaces analysed showed high RFA and BIC values, which were more favourable for the SLActive^® and ContacTi^® surfaces. No statistical correlation was found between the RFA and BIC values in any of the three surfaces analysed.

Chemical and Structural Characterization of Sandlasted Surface of Dental Implant using ZrO2 Particle with Different Shape

The clinical success of dental implantation is associated with the phenomenon of osteointegration. Geometry and topography of the implant surface are critical for the short- and long-term success of an implantation. Modification of the surface of endosseous part of the implant with sandblasting was of special interest for our study. Taking into account the advantages of currently used ceramic abrasives: aluminum oxide, titanium oxide, calcium phosphate, these materials are able to break down during collision with the treated surface, the possibility of incorporation of their residues into the implant surface, as well as the difficulty of removing these residues. This paper aimed to determine the preferred composition and the shape of the abrasive, as well as the treatment regime for ZrO2 sandblasting modification of the surface of the endosseous part of the dental implant. Tetragonal and cubic solid solutions are based on ZrO2, as an abrasive that is applied for zirconium-niobium alloy sandblasting under different pressures. Optical and scanning electron microscopy, the physical and chemical state of the surface of implants as well as contact angle measurement and cell viability were used to assess surface after sandblasting. The results demonstrate the potential of using granular powders that are based on zirconium dioxide as an abrasive to create a rough surface on endosseous part of dental implants made from zirconium-based alloys. It does not lead to a significant change in the chemical composition of the surface layer of the alloy and it does not require subsequent etching in order to remove the abrasive particles. Based on structural and chemical characterization, as well as on cell viability and contact angle measurement, sandblasting by tetragonal ZrO2 powder in 4 atm. and an exposure time of 5 s provided the best surface for dental implant application.

Predictive values of resonance frequency analysis as a diagnostic tool in palatal implant loss

OBJECTIVES

To determine the diagnostic value of resonance frequency analysis (RFA) in predicting palatal implant (PI) loss.

MATERIALS AND METHODS

RFA values of 32 patients (study center at Mainz and Dresden) were evaluated in a prospective randomized controlled trial addressing clinical performance of two loading concepts on PI (Orthosystem, Straumann, Basel, Switzerland). Group 1: conventional loading after a 12-week healing period vs group 2: immediate loading within one week after insertion. Stability was assessed by RFA after surgical insertion (T1), one week (T2), and 12 weeks (T3) later.

RESULTS

All 32 PI were clinically stable after surgical insertion; 14 PI were loaded conventionally and 18 immediately. One implant in group 1 was lost 6 weeks after insertion. One drop-out was registered in group 2. One false positive and three false negative implant stability quotients (ISQ) were observed. ISQ values of clinically stable PI in group 1 were 67.2 (SD ± 9.5) at T1, 62.3 (SD ± 11.7) at T2, and 68.2 (SD ± 5.5) at T3. Group 2 showed 67.1 (SD ± 11.7) at T1, 65.4 (SD ± 10.4) at T2, and 72.3 (SD ± 5.6) at T3. Differences between groups were not statistically significant for starting time (P = .88) and change from T1 to T2: 0.08 but were significant from T1 to T3: P = .04; (regression analysis).

CONCLUSIONS

RFA had no sensitivity for prediction of stability. General decrease after primary stability and increase with secondary stability gives support for specificity. Within the limits of the study, only the diagnostic value of RFA identifying stable palatal implants could be confirmed.

Influence of Implant Neck Design on Peri-Implant Tissue Dimensions: A Comparative Study in Dogs

This in vivo study assessed (hard and soft) peri-implant tissue remodeling around implants with micro-ring and open-thread neck designs placed in a dog model. Twenty histological sections corresponding to four different implant designs that were placed in America Foxhound dogs were obtained from previous studies. All the implants had been placed under identical conditions and were divided into four groups: Group A, micro-rings on implant neck plus 0.5 mm refined surface; Group B, micro-rings on implant neck; Group C, open-thread neck; and, Group D, double-spiral neck. Eight weeks after surgery, the integrated implants were removed and processed for histological examination. Crestal bone loss and bone-to-implant contact was greater for micro-ring necks than open-thread necks. Soft tissues showed significant differences on both buccal and lingual aspects, so that the distance from peri-implant mucosa to the apical portion of the barrier epithelium was smaller in the micro-ring groups. So, in spite of generating greater bone-to-implant contact, implants with micro rings produced more bone loss than open-thread implants. Moreover, the outcomes that were obtained IPX implants smooth neck design produced less bone loss in the cervical area, following by Facility implants when compared with the other open thread and microthreaded implant designs. Implant thread design can influence on bone remodeling in the cervical area, related to bundle bone preservation.

Plaque accumulation on titanium disks with different surface treatments: an in vivo investigation

Implants with rough surfaces are today widely used. It has been speculated that rough surfaces (Ra > 0.2 μm) provide a better "substrate" for retention and accumulation of plaque in terms of area, thickness and colony-forming unit that can eventually lead to peri mucositis and/or peri-implantitis. The aim of this investigation was to evaluate in vivo the plaque accumulation after 48 h on three implant surfaces with different treatments. For this investigation, we used 21 sterilized titanium disks, with a diameter of 8mm and a thickness of 3 mm, provided by the manufacturer: 7 with machined surface, as smooth control, 7 with HA grit sandblasted RBM surface and 7 with Ca⁺⁺ incorporated in titanium Xpeed surface. One disk for each surface treatment was characterized at time 0 by SEM and AFM to study, respectively, the surface morphology and roughness. The other 18 disks were mounted randomly on three upper acrylic bites in a buccal lateral position, worn for 48 h by three volunteer students for plaque accumulation. After 48 h each disk was removed and analyzed qualitatively and quantitatively by an independent operator, not involved into the study, in order to avoid bias. Data collected were statistically analyzed by one-way ANOVA. The qualitative analysis showed no differences in terms of total plaque accumulation between the surfaces. Data from quantitative analysis using Anova Test showed no significance between all groups. In this in vivo investigation all the surfaces studied promoted plaque formation. The degree of surface roughness seems not to be a critical factor for plaque accumulation.

Effect of Microthread Design on Marginal Bone Level Around Dental Implants Placed in Fresh Extraction Sockets

PURPOSE

This study was designed to compare radiographically the effect of microthread on the coronal portion of the fixture on marginal bone level (MBL) around immediately placed dental implants in human subjects.

MATERIAL AND METHODS

Forty-one roughened surface screw type Dentium oral implants (Dentium) were inserted in fresh extraction sockets of the anterior segment of maxilla of 30 patients. The implants were selected randomly using either microthread design on coronal portion of the fixture (Implantium) (test group) or without microthread thread design (Superline) (control group). MBL was measured using digital subtraction radiography technique after 3, 6, and 12 months.

RESULTS

At month 3, the microthread groups have been associated with more marginal bone loss than the control group (P = 0.04). At months 6 and 12, both groups had comparable bone levels (P = 0.21).

CONCLUSION

The microthread design of the implant collar could not have a positive effect in maintaining the MBL around implants placed in fresh extraction socket in anterior maxilla.

The effects of SOST on implant osseointegration in ovariectomy osteoporotic mice

OBJECTIVE

Osteoporosis is a risk factor for implant fixation failure. The inhibition of sclerostin effectively improves bone formation and bone remodeling. Therefore, this study investigated whether SOST deficiency enhances the osseointegration of implants in a mouse model of osteoporosis induced by ovariectomy (OVX).

DESIGN

Osteoporosis was induced in female C57BL/6 and SOST deficient mice by OVX. Titanium implants were placed in the bilateral distal aspects of the femurs. Implants underwent sandblasting and acid-etching after which the structure, surface roughness and chemical components were investigated using scanning electron microscopy (SEM) and energy spectrum analyses. Undecalcified slices, μ-CT, histology analyses and mechanical tests were used to evaluate the osseointegration of implants. The results were compared using one-way ANOVA between four groups.

RESULTS

Sandblasting and acid-etching increased the roughness of the implants. OVX surgery reduced bone formation around the implants in both WT and SOST^-/- mice. However, implant osseointegration was significantly improved in the SOST^-/- OVX mice compared to the WT OVX mice.

CONCLUSIONS

Inhibition of the SOST gene improved implant fixation in the OVX osteoporotic mice, which suggests a strategy for enhancing implant osseointegration in clinical patients with osteoporosis.

Effect of Heavy Smoking on Dental Implants Placed in Male Patients Posterior Mandibles: A Prospective Clinical Study

The objective of this study was to evaluate the implant stability and peri-implant tissue response in heavy smokers receiving dental implants due to partially edentulous posterior mandibles. Forty-five ITI Straumann dental implants were placed into the partially edentulous posterior mandibles of 16 heavy smokers and 16 nonsmokers. One implant in each patient was evaluated for implant stability after surgery and before loading, and for the modified plaque index (mPLI), modified sulcus bleeding index (mSBI), probing depth (PD), and marginal bone loss (MBL) after loading. Meanwhile, the osteogenic capability of jaw marrow samples collected from patients was evaluated via an in vitro mineralization test. For both groups, the implant stability quotient (ISQ) initially decreased from the initial ISQ achieved immediately after surgery and then increased starting from 2 weeks postsurgery. However, at 3, 4, 6, and 8 weeks postsurgery, the ISQ differed significantly between nonsmokers and heavy smokers. All implants achieved osseointegration without complications at least by the end of the 12th week postsurgery. At 6 or 12 months postloading, the MBL and PD were significantly higher in heavy smokers than in nonsmokers, whereas the mSBI and mPLI did not differ significantly between the 2 groups. The 1-year cumulative success rate of implants was 100% for both groups. Within the limitations of the present clinical study (such as small sample size and short study duration), which applied the loading at 3 months postoperation, heavy smoking did not affect the cumulative survival rate of dental implants placed at the posterior mandible in male patients, but heavy smoking did negatively affect bone healing around dental implants by decreasing the healing speed. These results implied that it might be of importance to select the right time point to apply the implant loading for heavy smokers. In addition, heavy smoking promoted the loss of marginal bone and the further development of dental pockets. Further clinical studies with larger patient populations are warranted to confirm our findings over a longer study duration.

A Comparative Study of Stability After the Installation of 2 Different Surface Types of Implants in the Maxillae of Dogs

PURPOSE

This study was performed to investigate the histologic and histomorphometric findings of 2 different types of implant.

MATERIALS AND METHODS

Resorbable blasting media (RBM) and sandblasted with larger grit and acid etched (SLA) surfaced implants (24 fixtures in each group) were installed in posterior maxilla of dogs. The initial stability was measured using Periotest (Periotest value [PTV]). After 6 or 12 weeks, fixtures with surrounding bone were harvested.

RESULTS

The average initial stability of the SLA group (-1.71 ± 2.9) was higher than that of the RBM group (-1.25 ± 3.21), but there was no significant difference. The mean PTV of the RBM surface was higher than the SLA surface at 12 weeks. The average bone-implant contacts were 67.6% ± 16.0% at 6 weeks and 82.7% ± 8.6% at 12 weeks in the SLA group and 69.9% ± 17.6% at 6 weeks and 78.3% ± 9.2% at 12 weeks in the RBM group.

CONCLUSION

The SLA and resorbable blasting media (RBM) surface implants demonstrated good stabilities and healing processes of the surrounding bone in the posterior maxilla. Therefore, the two domestic implants could provide predictable clinical results.

Decontamination methods using a dental water jet and dental floss for microthreaded implant fixtures in regenerative periimplantitis treatment

OBJECTIVE

This study evaluated decontamination methods using a dental water jet and dental floss on microthreaded implants for regenerative periimplantitis therapy.

MATERIALS AND METHODS

In 6 beagle dogs, experimental periimplantitis was induced, and decontamination procedures, including manual saline irrigation (control group), saline irrigation using a dental water jet (group 1) and saline irrigation using a dental water jet with dental flossing (group 2), were performed. After in situ decontamination procedures, some of the implant fixtures (n = 4 per group) were retrieved for analysis by SEM, whereas other fixtures (n = 4 per group) underwent regenerative therapy. After 3 months of healing, the animals were killed.

RESULTS

The SEM examination indicated that decontamination of the implant surfaces was the most effective in group 2, with no changes in implant surface morphology. The histological examination also revealed that group 2 achieved significantly greater amounts of newly formed bone (6.75 ± 2.19 mm; P = 0.018), reosseointegration (1.88 ± 1.79 mm; P = 0.038), and vertical bone fill (26.69 ± 18.42%; P = 0.039).

CONCLUSION

Decontamination using a dental water jet and dental floss on microthreaded implants showed positive mechanical debridement effects and positive bone regeneration effects.

Effect of microthreads on removal torque and bone-to-implant contact: an experimental study in miniature pigs

Purpose

The objective of this study was to evaluate the effect of microthreads on removal torque and bone-to-implant contact (BIC).

Methods

Twelve miniature pigs for each experiment, a total of 24 animals, were used. In the removal torque analysis, each animal received 2 types of implants in each tibia, which were treated with sandblasting and acid etching but with or without microthreads at the marginal portion. The animals were sacrificed after 4, 8, or 12 weeks of healing. Each subgroup consisted of 4 animals, and the tibias were extracted and removal torque was measured. In the BIC analysis, each animal received 3 types of implants. Two types of implants were used for the removal torque test and another type of implant served as the control. The BIC experiment was conducted in the mandible of the animals. The P1-M1 teeth were extracted, and after a 4-month healing period, 3 each of the 2 types of implants were placed, with one type on each side of the mandible, for a total of 6 implants per animal. The animals were sacrificed after a 2-, 4-, or 8-week healing period. Each subgroup consisted of 4 animals. The mandibles were extracted, specimens were processed, and BIC was analyzed.

Results

No significant difference in removal torque value or BIC was found between implants with and without microthreads. The removal torque value increased between 4 and 8 weeks of healing for both types of implants, but there was no significant difference between 8 and 12 weeks. The percentage of BIC increased between 2 and 4 weeks for all types of implants, but there was no significant difference between 4 and 8 weeks.

Conclusions

The existence of microthreads was not a significant factor in mechanical and histological stability.

Nanostructured surfaces of dental implants

The structural and functional fusion of the surface of the dental implant with the surrounding bone (osseointegration) is crucial for the short and long term outcome of the device. In recent years, the enhancement of bone formation at the bone-implant interface has been achieved through the modulation of osteoblasts adhesion and spreading, induced by structural modifications of the implant surface, particularly at the nanoscale level. In this context, traditional chemical and physical processes find new applications to achieve the best dental implant technology. This review provides an overview of the most common manufacture techniques and the related cells-surface interactions and modulation. A Medline and a hand search were conducted to identify studies concerning nanostructuration of implant surface and their related biological interaction. In this paper, we stressed the importance of the modifications on dental implant surfaces at the nanometric level. Nowadays, there is still little evidence of the long-term benefits of nanofeatures, as the promising results achieved in vitro and in animals have still to be confirmed in humans. However, the increasing interest in nanotechnology is undoubted and more research is going to be published in the coming years.

Accelerated bone formation on photo-induced hydrophilic titanium implants: an experimental study in the dog mandible

OBJECTIVES

The purpose of this study was to investigate the effect of photo-induced hydrophilic titanium dioxide (TiO₂) on serum fibronectin (sFN) attachment, and further to evaluate initial osseointegration responses in the dog mandibles.

MATERIALS AND METHODS

To apply the anatase TiO₂ film, plasma source ion implantation (PSII) method followed by annealing was employed for the titanium disks and implants, which were then illuminated with UV-A for 24 h for the experimental groups. Non-deposited titanium disks and implants were prepared for the control group. Surface characterization was performed using the interferometer and contact angle analyzer. The attachments of sFN were evaluated using fluorescence emission analysis. Thereafter both groups of implants were placed in the mandible of six beagle dogs. Bone response was investigated with histological and histomorphometrical analyses after periods of 2 and 4 weeks.

RESULTS

The experimental groups exhibited strong hydrophilicity under UV-A illumination and showed significant improvement in sFN attachment. And further, the experimental implants enhanced the bone formation with the bone-to-implant contact of 42.7% after 2 weeks of healing (control: 28.4%).

CONCLUSIONS

The combined applications of plasma fibronectin and PSII to produce hydrophilic titanium surfaces could accelerate early osseointegration.

The relationship between initial implant stability quotient values and bone-to-implant contact ratio in the rabbit tibia

PURPOSE

Implant stability quotient (ISQ) values have been supposed to predict implant stability. However, the relationship between ISQ values and bone-to-implant contact ratio (BIC%) which is one of the predictors of implant stability is still unclear. The aim of the present study was to evaluate initial ISQ values in relation to BIC% using rabbit model.

MATERIALS AND METHODS

Four New Zealand white rabbits received a total of 16 implants in their tibia. Immediately after implant placement ISQ values were assessed. The measurements were repeated at the time of sacrifice of the rabbits after 4 weeks. Peri-implant bone regeneration was assessed histomorphometrically by measuring BIC% and bone volume to total volume values (bone volume %). The relationships between ISQ values and the histomorphometric output were assessed, and then, the osseointegration prediction model via the initial ISQ values was processed.

RESULTS

Initial ISQ values showed significant correlation with the BIC%. The bone volume % did not show any significant association with the ISQ values.

CONCLUSION

In the limitation of this study, resonance frequency analysis is a useful clinical method to predict the BIC% values and examine the implant stability.

Early and immediate loading of titanium implants with fluoride-modified surfaces: results of 5-year prospective study

OBJECTIVE

Multiple experimental and animal studies have shown that topographic, mechanical and chemical properties of implant surfaces lead to in vivo responses such as increased bone formation, increased bone anchorage and reduced healing time. A fluoride modification of the titanium implant surface also seems to positively influence bone anchorage as compared with unmodified titanium implants. Using implant survival and marginal bone loss as primary outcome parameters, the purpose of the present prospective study was to investigate whether a fluoride modification of the titanium implant surface has positive clinical effects.

MATERIALS AND METHODS

The 17 patients included in this study received 49 Astra Tech OsseoSpeed implants for various indications in the maxilla and mandible. Implants were either loaded immediately or after a mean healing period of 9.56 weeks. Fifteen patients were followed up clinically including radiographic examination for 5 years. Forty-two implants were assessed for implant survival, marginal bone loss, surgical and/or prosthetic complications, presence or absence of plaque, signs of inflammation and size of the papilla.

RESULTS

Of the original 17 patients, 15 patients were available for the full 60-month follow-up. One early implant failure occurred, leading to an implant survival rate of 97%. Radiographic analyses demonstrated stable bone conditions with a mean marginal bone loss of 0.1 mm (SD 0.4 mm, min -0.7 mm, max 1.7 mm) after 5 years of function. Immediately loaded implants did not show a different mean marginal bone loss as compared with implants that were not loaded immediately. Repeated soft-tissue examinations revealed healthy conditions in terms of 6.1% plaque and 4.2% of the implants with signs of inflammation at the 5-year control.

DISCUSSION

Implants used in this study had high survival and success rates after 5 years. Marginal bone was well maintained, irrespective of the loading regime.

Factors influencing resonance frequency analysis assessed by Osstell mentor during implant tissue integration: II. Implant surface modifications and implant diameter

OBJECTIVES

To monitor the development of the stability of Straumann tissue-level implants during the early phases of healing by resonance frequency analysis (RFA) and to determine the influence of implant surface modification and diameter.

MATERIAL AND METHODS

A total of twenty-five 10 mm length implants including 12 SLA RN v4.1 mm implants, eight SLActive RN v4.1 mm implants and five SLA WN v4.8 mm implants were placed. Implant stability quotient (ISQ) values were determined with Osstell mentor at baseline, 4 days, 1, 2, 3, 4, 6, 8 and 12 weeks post-surgery. ISQ values were compared between implant types using unpaired t-tests and longitudinally within implant types using paired t-tests.

RESULTS

During healing, ISQ decreased by 3-4 values after installation and reached the lowest values at 3 weeks. Following this, the ISQ values increased steadily for all implants and up to 12 weeks. No significant differences were noted over time. The longitudinal changes in the ISQ values showed the same patterns for SLA implants, SLActive implants and WB implants. At placement, the mean ISQ values were 72.6, 75.7 and 74.4, respectively. The mean lowest ISQ values, recorded at 3 weeks, were 69.9, 71.4 and 69.8, respectively. At 12 weeks, the mean ISQ values were 76.5, 78.8 and 77.8, respectively. The mean ISQ values at all observation periods did not differ significantly among the various types. Single ISQ values ranged from 55 to 84 during the entire healing period. Pocket probing depths of the implants ranged from 1 to 3 mm and bleeding on probing from 0 to 2 sites/implant post-surgically.

CONCLUSIONS

All ISQ values indicated the stability of Straumann implants over a 12-week healing period. All implants showed a slight decrease after installation, with the lowest ISQ values being reached at 3 weeks. ISQ values were restored 8 weeks post-surgically. It is recommended to monitor implant stability by RFA at 3 and 8 weeks post-surgically. However, neither implant surface modifications (SLActive) nor implant diameter were revealed by RFA.

Implant stability and peri-implant parameters in free vascularized iliac graft transplantation patients: report of three ameloblastoma cases

BACKGROUND

Ameloblastoma, a benign but locally aggressive tumor, accounts for 9% to 11% of all odontogenic tumors. Radical procedures, including resection, are performed. To restore functions after resection, free vascularized iliac grafts followed by a dental implant-supported prosthesis are used as a successful treatment option. The aim of this case report is to evaluate the peri-implant clinical status and stability of dental implants placed in patients with advanced-stage mandibular ameloblastomas.

METHODS

Examinations of three patients revealed extensive ameloblastomas, and hemimandibulectomies were performed. Six months after surgeries, two to four dental implants were placed. After 6 months of healing, one fixed prosthesis and two removable prostheses were delivered. The stability of implants was evaluated at the surgical baseline and 1, 3, 6, 9, and 12 months after surgery by resonance-frequency (RF) analysis. Peri-implant clinical parameters (i.e., plaque index [PI], gingival index [GI], gingival bleeding time index [GBTI], and peri-implant probing depth [PD]) were recorded at the delivery of the prosthesis and at follow-ups at 1, 3, and 6 months.

RESULTS

Nine implants that supported one removable prosthesis and two fixed prostheses were placed. RF analysis revealed no significant changes in implant stability during 12 months of follow-up. Peri-implant clinical parameters (PI, GI, and GBTI) showed slight improvements during follow-up. Although advancements were observed in 6 months, PDs were found to be deeper than optimal measurements for the whole observation time.

CONCLUSION

The implant-supported prosthetic rehabilitation of patients with ameloblastomas reconstructed with free vascularized iliac crest grafts can be a predictive alternative for improving the quality of life of patients in which a high implant stability and acceptable peri-implant health may be achieved.

Effect of conical configuration of fixture on the maintenance of marginal bone level: preliminary results at 1 year of function

OBJECTIVES

To evaluate and to compare the effect of the conical neck design on marginal bone loss around the fixtures, when both implants were provided with micro-threads to the top of the fixture.

MATERIALS AND METHODS

Two types of implant, one with a straight shape (S) and the other with a conical neck design (C) provided with a retentive element to the top of the fixture, were placed adjacent to each other in the partially edentulous areas of 12 patients. Bone loss around each implant was analyzed after 1 year of functional loading. The bone losses after loading were compared using Wilcoxon's signed-rank test.

RESULTS

The mean marginal bone losses (S, 0.05 + or - 0.09 mm; C, 0.07 + or - 0.14 mm) were not statistically significant between the two groups (P=0.578).

CONCLUSIONS

There was no significant difference between conical and straight neck implants in terms of marginal bone loss after 1 year of loading.

Bone Particles and the Undersized Surgical Technique

During the installation of implants, osteogenic bone particles are translocated along the surface. These particles may contribute to peri-implant bone healing. Based on this phenomenon, it is hypothesized that implants placed with undersized drilling, besides showing higher primary-implant stability, also enhance the amount and osteogenic responses of these bone particles. Biocomp® implants were inserted into bicortical fresh-cadaver bone by a press-fit or an undersized surgical technique, and peak-insertion torque values (ITV) were measured. After explantation, the implants were incubated in culture medium up to 24 days. Histology, bone-implant contact (BIC), micro-CT, scanning electron microscopy (SEM), and calcium (Ca) measurements were performed. ITV were significantly higher for implants placed with an undersized technique. Moreover, histology, BIC, micro-CT, SEM, and Ca measurements confirmed the presence of more bone-like tissue on implants inserted with an undersized technique. The undersized surgical technique not only results in higher primary-implant stability, but also induces more translocated bone particles, thus having a positive influence on the osteogenic response.

A clinical study of alveolar bone quality using the fractal dimension and the implant stability quotient

Purpose

It has been suggested that primary implant stability plays an essential role in successful osseointegration. Resonance frequency analysis (RFA) is widely used to measure the initial stability of implants because it provides superior reproducibility and non-invasiveness. The purpose of this study is to investigate whether the fractal dimension from the panoramic radiograph is related to the primary stability of the implant as represented by RFA.

Methods

This study included 22 patients who underwent dental implant installation at the Department of Periodontology of Seoul National University Dental Hospital. Morphometric analysis and fractal analysis of the bone trabecular pattern were performed using panoramic radiographs, and the implant stability quotient (ISQ) values were measured after implant installation using RFA. The radiographs of 52 implant sites were analyzed, and the ISQ values were compared with the results from the morphometric analysis and fractal analysis.

Results

The Pearson correlation showed a linear correlation between the ISQ values of RFA and the parameters of morphometric analysis but not of statistical significance. The fractal dimension had a linear correlation that was statistically significant. The correlation was more pronounced in the mandible.

Conclusions

In conclusion, we suggest that the fractal dimension acquired from the panoramic radiograph may be a useful predictor of the initial stability of dental implants.