Pilot clinical and histologic evaluations of a two-piece zirconia implant

An investigation was conducted to evaluate the clinical and histologic results of bone and soft tissue healing around a two-piece zirconia dental implant in a human model. A healthy female patient requiring tooth replacement with dental implants received a two-piece zirconia implant together with conventional titanium implants to be implemented in a prosthesis. Clinical and radiographic evaluations at 6 months revealed stable osseointegrated zirconia and titanium dental implants. Light microscopy and backscatter scanning electron microscopic analyses confirmed the biocompatibility and achievement of osseointegration, in addition to maintenance of the crestal bone level. The findings suggest that the bone-to-implant contact with a zirconia implant surface is sufficient to provide clinical and histologic evidence of osseointegration. The biopsied two-piece zirconia dental implant with platform switching demonstrated osseointegration occlusal to the implant-abutment junction, eliminating the significance of the microgap.     

Loaded custom-made zirconia and titanium implants show similar osseointegration: an animal experiment

BACKGROUND: Zirconia might be an alternative material to titanium for dental implant fabrication. The aim of the present study was to investigate the histological behavior (osseointegration) of loaded zirconia implants in an animal model and to compare it with the behavior of titanium implants. METHODS: Five months after extraction of the upper anterior teeth, 12 custom-made titanium implants (control group) and 12 custom-made zirconia implants (test group) were inserted in the extraction sites in six monkeys. Before insertion, the titanium implant surfaces were sandblasted with Al2O3 and subsequently acid-etched. The zirconia implants were only sandblasted. Six months following implant insertion, impressions were taken for the fabrication of single crowns. A further 3 months later, nonprecious metal crowns were inserted. Five months after insertion of the crowns, the implants with the surrounding hard and soft tissues were harvested, histologically prepared, and evaluated under the light microscope regarding the peri-implant soft tissue dimensions and mineralized bone-to-implant contact. RESULTS: No implant was lost during the investigational period. The mean height of the soft peri-implant tissue cuff was 5 mm around the titanium implants and 4.5 mm around the zirconia implants. No statistically significant differences were found in the extent of the different soft tissue compartments. The mean mineralized bone-to-implant contact after 9 months of healing and 5 months of loading amounted to 72.9% (SD: 14%) for the titanium implants and to 67.4% (SD: 17%) for the zirconia implants. There was no statistically significant difference between the different implant materials. CONCLUSION: Within the limits of this animal experiment, it can be concluded that the custom-made zirconia implants osseointegrated to the same extent as custom-made titanium control implants and show the same peri-implant soft tissue dimensions.     

Temporal sequence of hard and soft tissue healing around titanium dental implants

The objective of the present review was to summarize the evidence available on the temporal sequence of hard and soft tissue healing around titanium dental implants in animal models and in humans. A search was undertaken to find animal and human studies reporting on the temporal dynamics of hard and soft tissue integration of titanium dental implants. Moreover, the influence of implant surface roughness and chemistry on the molecular mechanisms associated with osseointegration was also investigated. The findings indicated that the integration of titanium dental implants into hard and soft tissue represents the result of a complex cascade of biological events initiated by the surgical intervention. Implant placement into alveolar bone induces a cascade of healing events starting with clot formation and continuing with the maturation of bone in contact with the implant surface. From a genetic point of view, osseointegration is associated with a decrease in inflammation and an increase in osteogenesis‐, angiogenesis‐ and neurogenesis‐associated gene expression during the early stages of wound healing. The attachment and maturation of the soft tissue complex (i.e. epithelium and connective tissue) to implants becomes established 6–8 weeks following surgery. Based on the findings of the present review it can be concluded that improved understanding of the mechanisms associated with osseointegration will provide leads and targets for strategies aimed at enhancing the clinical performance of titanium dental implants.     

3D打印和CAD/CAM氧化锆种植体骨结合性能的动物实验评价

目的 比较3D打印和计算机辅助设计与制造(CAD/CAM)氧化锆种植体与纯钛种植体在动物体内的骨结合和成骨效果的差异,评价氧化锆种植体骨结合性能.方法 分别将3D打印氧化锆、CAD/CAM种植体和钛种植体各20枚随机植入6只Beagle犬的胫骨内,8周后观察氧化锆种植体的成功率和骨结合能力,并与钛种植体进行比较,观察指...     

Comparison of zirconia and titanium implants after a short healing period. A pilot study in minipigs

The aim of this animal study was to investigate and compare the osseointegration of zirconia and titanium dental implants. 14 one-piece zirconia implants and 7 titanium implants were inserted into the mandibles of 7 minipigs. The zirconia implants were alternately placed submerged and non-submerged. To enable submerged healing, the supraosseous part was removed, using a diamond saw. The titanium implants were all placed submerged. After a healing period of 4 weeks, a histological analysis of the soft and hard tissue and a histomorphometric analysis of the bone–implant contact (BIC) and relative peri-implant bone-volume density (rBVD; relation to bone-volume density of the host bone) was performed. Two zirconia implants were found to be loose. All other implants were available for evaluation. For submerged zirconia and titanium implants, the implant surface showed an intimate connection to the neighbouring bone, with both types achieving a BIC of 53%. For the non-submerged zirconia implants, some crestal epithelial downgrowth could be detected, with a resultant BIC of 48%. Highest rBVD values were found for submerged zirconia (80%), followed by titanium (74%) and non-submerged zirconia (63%). The results suggest that unloaded zirconia and titanium implants osseointegrate comparably, within the healing period studied.     

Clinical performance of one‐piece zirconia dental implants: A systematic review

The aim of the present review was to evaluate the clinical and radiographic performance of one‐piece zirconia implants (O‐PZI). This review followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta‐Analysis) guidelines that addressed the following focused question: What is the overall clinical and radiographic performance of O‐PZI? The MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register databases were searched. Six clinical studies were included. For studies evaluating O‐PZI compared with one‐piece titanium implants, zirconia implants showed higher crestal bone loss (CBL) in both the studies. However, one study demonstrated a high failure rate compared to titanium dental implants, while one study demonstrated comparable survival rates between zirconia and titanium dental implants. For studies evaluating O‐PZI for the restoration of single crown and fixed dental prostheses, O‐PZI showed comparable bone loss and survival rates for single crowns and fixed dental prostheses. Two studies were included that compared O‐PZI with two‐piece zirconia (T‐PZI). One study showed a higher CBL and low survival rate for O‐PZI compared to T‐PZI, whereas the other study demonstrated comparable CBL and survival rates between O‐PZI and T‐PZI. It is still debatable whether O‐PZI demonstrate better clinical performance when compared with titanium implants or two‐piece design.     

Is zirconia a viable alternative to titanium for oral implant? A critical review

Purpose

Titanium based implant systems, though considered as the gold standard for rehabilitation of edentulous spaces, have been criticized for many inherent flaws. The onset of hypersensitivity reactions, biocompatibility issues, and an unaesthetic gray hue have raised demands for more aesthetic and tissue compatible material for implant fabrication. Zirconia is emerging as a promising alternative to conventional Titanium based implant systems for oral rehabilitation with superior biological, aesthetics, mechanical and optical properties. This review aims to critically analyze and review the credibility of Zirconia implants as an alternative to Titanium for prosthetic rehabilitation.

Prosthodontic considerations designed to optimize outcomes for single-tooth implants. A review of the literature

Background: The aim of this study was to review the literature on the restoration of single‐tooth implants, and to develop evidence‐based conclusions to optimize aesthetic, biologic and patient‐related outcomes. Methods: An electronic and hand search was conducted using the search terms ‘dental implants, single‐tooth; dental restoration, temporary; dental impression materials; dental impression technique; dental prosthesis, implant‐supported; dental prosthesis design; dental abutments; dental occlusion; maintenance; survival; and survival analysis’. Resultant titles were screened, and full text was obtained where relevant. The authors selected the most appropriate articles, giving preference to systematic reviews and long‐term, patient‐based outcome data. Results: Thirty‐nine articles were selected and critiqued by the authors. Conclusions: There was strong suggestion by several authors that peri‐implant soft tissue aesthetics can be sculpted through provisional restoration contour, but there are no clinical outcome studies to define or support this claim. Laboratory studies demonstrate that pick‐up type impression copings in conjunction with elastomeric impressions are the most accurate means for transferring implant position to a dental cast. Laboratory and finite‐element analysis studies suggest implants with an internal‐type connection show improved stress distribution, but supportive clinical data are lacking. The authors of this review favour a screw‐retained prosthesis for retrievability. Clinical and histological studies show that gold, titanium and zirconia ceramic abutment materials exhibit excellent biological responses, although there is insufficient data on the clinical service provided by zirconia as an implant‐substructure material. The literature does not associate any particular occlusal scheme with superior clinical outcomes. Implant‐borne single crowns offer comparable clinical service to tooth‐borne fixed dental prostheses. However, single‐tooth implant restorations are associated with an increased incidence of biological and technical complications.     

Osseointegration of one‐piece zirconia implants compared with a titanium implant of identical design: a histomorphometric study in the dog

Objective: The aim of this study was to evaluate osseointegration of one‐piece zirconia vs. titanium implants depending on their insertion depth by histomorphometry. Material and methods: Four one‐piece implants of identical geometry were inserted on each side of six mongrel dogs: (1) an uncoated zirconia implant, (2) a zirconia implant coated with a calcium‐liberating titanium oxide coating, (3) a titanium implant and (4) an experimental implant made of a synthetic material (polyetheretherketone). In a split‐mouth manner they were inserted in submerged and non‐submerged gingival healing modes. After 4 months, dissected blocks were stained with toluidine blue in order to histologically assess the bone‐to‐implant contact (BIC) rates and the bone levels (BL) of the implants. Results: All 48 implants were osseointegrated clinically and histologically. Histomorphometrically, BL in the crestal implant part did not differ significantly with regard to material type or healing modality. The submerged coated zirconia implants tended to offer the most stable crestal BL. The histometric results reflected the different healing modes by establishing different BL. The median BIC of the apical implant part of the zirconia and titanium group amounted to 59.2% for uncoated zirconia, 58.3% for coated zirconia, 26.8% for the synthetic material and 41.2% for titanium implants. Conclusions: Within the limits of this animal study, it is concluded that zirconia implants are capable of establishing close BIC rates similar to what is known from the osseointegration behaviour of titanium implants with the same surface modification and roughness. To cite this article:
Koch FP, Weng D, Krämer S, Biesterfeld S, Jahn‐Eimermacher A, Wagner W. Osseointegration of one‐piece zirconia implants compared with a titanium implant of identical design: a histomorphometric study in the dog.
Clin. Oral Impl. Res. 21 , 2010; 350–356.
doi: 10.1111/j.1600‐0501.2009.01832.x     

Current status of zirconia implants in dentistry: preclinical tests

Purpose

This systematic review aimed to provide an overview of zirconia implants as well as regarding the outcome of the implant-restorative complex in preclinical studies.

Techniques for dental implant nanosurface modifications

PURPOSE

Dental implant has gained clinical success over last decade with the major drawback related to osseointegration as properties of metal (Titanium) are different from human bone. Currently implant procedures include endosseous type of dental implants with nanoscale surface characteristics. The objective of this review article is to summarize the role of nanotopography on titanium dental implant surfaces in order to improve osseointegration and various techniques that can generate nanoscale topographic features to titanium implants.

MATERIALS AND METHODS

A systematic electronic search of English language peer reviewed dental literature was performed for articles published between December 1987 to January 2012. Search was conducted in Medline, PubMed and Google scholar supplemented by hand searching of selected journals. 101 articles were assigned to full text analysis. Articles were selected according to inclusion and exclusion criterion. All articles were screened according to inclusion standard. 39 articles were included in the analysis.

RESULTS

Out of 39 studies, seven studies demonstrated that bone implant contact increases with increase in surface roughness. Five studies showed comparative evaluation of techniques producing microtopography and nanotopography. Eight studies concluded that osteoblasts preferably adhere to nano structure as compared to smooth surface. Six studies illustrated that nanotopography modify implant surface and their properties. Thirteen studies described techniques to produce nano roughness.

CONCLUSION

Modification of dental osseous implants at nanoscale level produced by various techniques can alter biological responses that may improve osseointegration and dental implant procedures.     

A comparison of femoral and mandibular animal models for the evaluation of HA-coated implants.

The application of hydroxylapatite coatings promises marked improvement in the rapidity and durability of osseointegration for both dental and orthopedic metallic implants. Standard methods for the in vivo assessment of the performance of experimental implants include canine mandibular and femoral transcortical implantations. This study compared the results of the two procedures by use of similar HA-coated titanium implants. The results indicate that the rapidity of osseointegration and the maximum attachment strength for mandibular dental implants approximate those of the femoral transcortical implants, especially at longer post-operative intervals. We conclude that the two models are comparable for the purpose of evaluating the performance of this type of implant and can be used interchangeably by dental and orthopedic implant designers. HA-coating of titanium implants provides extensive osseointegration in both mandibular and long-bone models, with similar mechanical attachment strengths and histologic appearance.     

Comparison of chemically and pharmaceutically modified titanium and zirconia implant surfaces in dentistry: a study in sheep

Advanced surface modifications and materials were tested on the same implant geometry. Six types of dental implants were tested for osseointegration after 2, 4 and 8 weeks in a sheep pelvis model. Four titanium implant types were treated with newly developed surface modifications, of which two were chemically and two were pharmacologically modified. One implant was made of zirconia. A sandblasted and acid-etched titanium surface was used as reference. The chemically modified implants were plasma-anodized or coated with calcium phosphate. The pharmacological coatings contained either bisphosphonate or collagen type I with chondroitin sulphate. The implants were evaluated using macroscopic, radiographic and histomorphometric methods. All implants were well osseointegrated at the time of death. All titanium implants had similar bone implant contact (BIC) at 2 weeks (57-61%); only zirconia was better (77%). The main BIC increase was between 2 and 4 weeks. The pharmacologically coated implants (78-79%) and the calcium phosphate coating (83%) showed similar results compared with the reference implant (80%) at 8 weeks. There were no significant differences in BIC. Compared with previous studies the results of all implants were comparatively good.     

Outcomes of Dental Implants in Osteoporotic Patients. A Literature Review

Purpose: This article reviews available data on the outcome of dental implants in osteoporotic patients.
Materials and Methods: A search was performed in PubMed and completed in July 2007. The keywords "dental AND implants AND osteoporosis,""dental AND implants AND age,""dental AND implants AND gender," and "dental AND implants AND bone AND quality," with no limitations for language or year of publication, resulted in 82, 598, 94, and 541 articles, respectively. After abstract scanning (in case of doubt the article was read), 39 nonreview articles studying dental implant outcomes in osteoporotic/osteopenic subjects remained for our review. The bibliographies of the 39 articles were also inspected, but no additional studies were identified.
Results: Thirteen of 16 animal studies found lower osseointegration rates in osteoporotic/osteopenic bone than in normal bone. Six in nine clinical reports mention success. Eight of 12 studies in humans support the applicability of dental implants in osteoporotic patients.
Conclusions: There are no data to contraindicate the use of dental implants in osteoporotic patients; however, a proper adjustment of the surgical technique and a longer healing period may be considered in order to achieve osseointegration. Data on the use of biphosphonates in osteoporotic patients and implant outcomes are very limited, and no conclusions can be drawn. In addition, large prospective studies investigating the long-term success of dental implants in osteoporotic individuals are required.     

Surface treatments of titanium dental implants for rapid osseointegration.

The osseointegration rate of titanium dental implants is related to their composition and surface roughness. Rough-surfaced implants favor both bone anchoring and biomechanical stability. Osteoconductive calcium phosphate coatings promote bone healing and apposition, leading to the rapid biological fixation of implants. The different methods used for increasing surface roughness or applying osteoconductive coatings to titanium dental implants are reviewed. Surface treatments, such as titanium plasma-spraying, grit-blasting, acid-etching, anodization or calcium phosphate coatings, and their corresponding surface morphologies and properties are described. Most of these surfaces are commercially available and have proven clinical efficacy (>95% over 5 years). The precise role of surface chemistry and topography on the early events in dental implant osseointegration remain poorly understood. In addition, comparative clinical studies with different implant surfaces are rarely performed. The future of dental implantology should aim to develop surfaces with controlled and standardized topography or chemistry. This approach will be the only way to understand the interactions between proteins, cells and tissues, and implant surfaces. The local release of bone stimulating or resorptive drugs in the peri-implant region may also respond to difficult clinical situations with poor bone quality and quantity. These therapeutic strategies should ultimately enhance the osseointegration process of dental implants for their immediate loading and long-term success.     

Osseointegration of titanium,titanium alloy and zirconia dental implants: current knowledge and open questions

Bone healing around dental implants follows the pattern and sequence of intramembraneous osteogenesis with formation of woven bone first of all followed later by formation of parallel‐fibered and lamellar bone. Bone apposition onto the implant surface starts earlier in trabecular bone than in compact bone. While the first new bone may be found on the implant surface around 1 week after installation, bone remodeling starts at between 6 and 12 weeks and continues throughout life. Bone remodeling also involves the bone–implant interface, thus transiently exposing portions of the implant surface. Surface modifications creating micro‐rough implant surfaces accelerate the osseointegration process of titanium implants, as demonstrated in numerous animal experiments. Sandblasting followed by acid‐etching may currently be regarded as the gold standard technique to create micro‐rough surfaces. Chemical surface modifications, resulting in higher hydrophilicity, further increase the speed of osseointegration of titanium and titanium‐zirconium implants in both animals and humans. Surface modifications of zirconia and alumina‐toughened zirconia implants also have an influence on the speed of osseointegration, and some implant types reach high bone‐to‐implant contact values in animals. Although often discussed independently of each other, surface characteristics, such as topography and chemistry, are virtually inseparable. Contemporary, well‐documented implant systems with micro‐rough implant surfaces, placed by properly trained and experienced clinicians, demonstrate high long‐term survival rates. Nevertheless, implant failures do occur. A low percentage of implants are diagnosed with peri‐implantitis after 10 years in function. In addition, a low number of implants seem to be lost for primarily reasons other than biofilm‐induced infection. Patient factors, such as medications interfering with the immune system and bone cells, may be an element contributing to continuous bone loss and should therefore be monitored and studied in greater detail.     

不同表面处理方法对CAD/CAM氧化锆种植体表面显微形貌的影响研究

目的：：研究采用不同表面处理方法对CAD/CAM氧化锆种植体表面显微形貌特征及粗糙度的影响。方法：通过CAD/CAM技术加工氧化锆圆盘与一段式氧化锆种植体( Y-TZP, WIELAND),根据表面处理方式分为终烧结表面、喷砂表面及喷砂加热酸蚀处理表面;标准对照组选用BEGO钛种植体表面。各组圆盘试件及种植体用扫描电子显微镜及Keyence 3D激光显微形貌测量显微镜进行表面显微形貌观察与测量。采用单因素方差分析比较各组统计学差异。结果：各组CAD/CAM氧化锆试件表面显微形貌观察显示,喷砂后表面出现边缘锐利的凹坑及沟槽;喷砂加热酸蚀处理后,氧化锆表面可见纳米级的微小孔隙及沟纹。氧化锆种植体粗糙度测量结果显示：终烧结组的表面粗糙度值(Ra=0.69μm)显著低于其他3组(P<0.001),喷砂组Ra值(Ra=1.30μm)显著低于喷砂加热酸蚀组(Ra=1.49μm)及BEGO钛种植体组(Ra=1.57μm)(P<0.01),而喷砂加热酸蚀组与BEGO钛种植体组则无显著差异(P=0.196)。结论：CAD/CAM氧化锆试件终烧结后喷砂或喷砂加热酸蚀处理均可获得较为理想的表面粗糙度,热酸蚀处理能够改变氧化锆表面的纳米级微观结构。     

A role for surface topography in creating and maintaining bone at titanium endosseous implants

STATEMENT OF PROBLEM: A variety of claims are made regarding the effects of surface topography on implant osseointegration. Many in vivo and in vitro experimental observations have key limitations in their interpretations. PURPOSE: This review considers the major claims made concerning the effects of commercially pure (cp) titanium implant surface topography on osseointegration. Important findings of consensus are highlighted, and existing controversies are revealed. MATERIAL AND METHODS: This review considers many of the research publications listed in MEDLINE and presented in biomedical research publications and textbooks. RESULTS: Implant surface topography is not well defined in the marketplace or consistently reported among experimental studies. Many in vitro evaluations are not predictive of or correlated with in vivo outcomes. In some culture models, increased surface topography positively affects pro-osteogenic cellular activities. Animal models reveal modest increases in bone-to-implant contact and increases in the biomechanical interlock of the implant with bone for implants of increased surface topography. Existing information fails to define increased surface topography as a risk factor for peri-implant inflammation. CONCLUSION: Increased cp titanium implant surface topography improves the bone-to-implant contact and the mechanical properties of the enhanced interface. Growing clinical evidence for increased bone-to-implant contact at altered cp titanium implants confirms the temporally limited observations made in preclinical studies. In the absence of controlled comparative clinical trials, the aggregate experimental evidence supports the use of cp titanium implants with increased surface topography.     

The influence of statins on osseointegration: a systematic review of animal model studies

Recent research data have suggested that the beneficial action of statins in bone tissue could improve osseointegration around titanium implants by increasing the bone implant contact (BIC), the expression of bone morphogenetic protein‐2 (BMP‐2) and vascular endothelial growth factor (VEGF). The aim of this systematic review was to evaluate the influence of statins on osseointegration of titanium implants in animal studies. Two reviewers searched independently four databases (MEDLINE, SCOPUS, WEB OF SCIENCE and the Cochrane Library), until March 15, 2016. The Cochrane Collaboration’s Tool for Assessing Risk of Bias was used to assess the quality of the included studies. Papers that reported outcome data considering bone implant contact (BIC), mechanical tests or other histological evaluation were eligible for inclusion. 312 references were eletronically retrieved, 21 full‐text papers were screened and 17 studies were included. Thirteen trials presented histomorphometry data on bone implant contact measures. All of them showed a significant improved BIC when using statins. Despite data from included studies point to beneficial effects, standardized studies and with less risk of bias, are needed to clarify the role of statins on osseointegration.