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.     

Efficacy of systemic bisphosphonate delivery on osseointegration of implants under osteoporotic conditions: Lessons from animal studies

Background

The aim was to systematically review the role of systemic bisphosphonate (BP) delivery on osseointegration of implants under osteoporotic conditions.

Methods

The addressed focused question was “Does systemic BP delivery enhance osseointegration of implants under osteoporotic conditions?” PubMed/MEDLINE and Google-Scholar databases were searched from 1994 up to and including December 2013 using different combinations of the following keywords: “bone to implant contact”, “implant”, “bisphosphonate”, “osseointegration” and “osteoporosis”. Review articles, case-reports, commentaries, letters to the Editor, unpublished articles and articles published in languages other than English were excluded.

Results

Fifteen animal studies fulfilled our eligibility criteria. Osteoporotic conditions were induced via bilateral ovariectomy (OVX). BPs used in the studies were ibandronate, zoledronic acid and alendronate. Results from 12 studies showed that systemic BP delivery significantly increased bone volume and bone-to-implant contact under osteoporotic conditions. Two studies reported no significant difference in osseointegration among OVX animals with and without systemic BP delivery. In one study, systemic BP delivery negatively influenced implant osseointegration. Rough-surfaced and polished implants were used in 11 and one study respectively. In 3 studies implant surface characteristics remained unclear.

Conclusion

Within the limits of the present study, it is concluded that systemic BP delivery enhances implant osseointegration in animals with induced osteoporotic conditions. However, in a clinical scenario, the potential risk of BP related ONJ in osteoporotic patients undergoing dental implant therapy cannot be disregarded.     

Osseointegration and clinical success of zirconia dental implants: a systematic review

PURPOSE: Various ceramic implant systems made of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) have become commercially available in recent years. A systematic search of the literature was performed to assess the clinical success of dental Y-TZP implants and whether the osseointegration of Y-TZP is comparable to that of titanium, the standard implant material. MATERIALS AND METHODS: The internet database MEDPILOT was searched cumulatively for the keywords zircon* and dent* and implant as well as for zircon* and osseointegration. The last search was conducted on January 31st, 2007. Subsequently, the reference lists of the relevant publications were searched. Furthermore, a letter was sent to the 5 identified manufacturers of zirconia dental implants to ask for peer-reviewed publications. RESULTS: Ninety-six articles were found by the search strategy. No controlled clinical studies in humans regarding clinical outcomes or osseointegration could be identified. Clinical data were restricted to case studies and case series. Only 7 animal studies fulfilled the inclusion criteria. Osseointegration was evaluated at 4 weeks to 24 months after placement in different animal models and sites and under different loading conditions. The mean bone-implant contact percentage was above 60% in almost all experimental groups. In studies that used titanium implants as a control, Y-TZP implants were comparable to or even better than titanium implants. Surface modifications may further improve initial bone healing and resistance to removal torque. CONCLUSIONS: Y-TZP implants may have the potential to become an alternative to titanium implants but cannot currently be recommended for routine clinical use, as no long-term clinical data are available.     

Effect of alendronate on endosseous implant integration: an in vivo study in rabbits.

PURPOSE: Alendronate sodium (Fosamax; Merck, Whitehouse Station, NJ) is a second-generation bisphosphonate used widely in osteopenic individuals for decreasing bone resorption and increasing bone density. The ability of alendronate to affect systemic bone remodeling raises natural questions about the drug's influence on dental implant osseointegration. Current knowledge regarding the effect of systemic bisphosphonates, specifically alendronate, on all 3 phrases of osseointegration is incomplete and only a few studies have started to investigate peri-implant bone responses to alendronate-coated implants. The purpose of this study was to determine the effect of systemic alendronate therapy on osseointegration of dental implants based on torque-removal values in rabbits. MATERIALS AND METHODS: Identical titanium dental implants were placed using a standardized surgical protocol in the bilateral distal femur and proximal tibia of 20 New Zealand white rabbits (79 implants total). One week before implant placement, 10 rabbits were given doses of alendronate and continued on weekly dosing for 5 weeks until euthanized. The other 10 rabbits were untreated controls. Torque-removal values were determined using a Tohinichi 15-BTG torque wrench (Tohinichi Mfg Co, Ltd, Tokyo, Japan) for all implants. RESULTS: Analysis of torque data showed no statistical differences between the alendronate and control groups in both femur and tibia sites. A statistically significant difference, however, was noted in torque removal values between femur and tibia sites regardless of drug or non-drug groups. CONCLUSIONS: In summary, orally dosed alendronate administration in rabbits had no significant effect on dental implant torque-removal values 6 weeks after endosseous placement in femur and tibia.     

Placement and restoration of dental implants in a patient with Paget's disease in remission: literature review and clinical report.

Paget's disease is a disorder of bone that results in the replacement of normal bone with highly vascularized, low density bone. The diminished bone quality associated with Paget's disease is a relative contraindication to the use of dental implants, as it interferes with achievement of osseointegration. There is no current literature on the success of dental implants in patients with Paget's disease. Furthermore, there is no current literature on dental implant success in patients with remissive Paget's disease or in bone that appears to be unaffected by the disease in patients with Paget's. This case report follows the treatment of a patient with a partially edentulous maxilla and mandible (ACP PDI Classification III) who presented with remissive Paget's disease. Definitive treatment included the placement of four endosseous implants used to retain full veneer crowns. Despite the radiographic appearance of adequate bone quality, upon surgical placement it was discovered that the quality of bone was poor, yet implant survival was achieved through careful surgical management and rigid splinting of some of the endosseous implants.     

Osseointegration of two types of implants in nonhuman primates

Branemark developed a dental implant that can reliably replace missing teeth. The success of this implant is attributed to a direct connection of bone with the implant (osseointegration). Several implants, including the Core-Vent implant, adhere to the requirements described by Branemark and his coworkers to achieve osseointegration, yet no studies have attempted to directly compare osseointegration of the Biotes implant with other implants. This study directly compared the response of bone to the unloaded and occlusally loaded Core-Vent and Biotes implants at the light microscopic level by using the nonhuman primate model. Histologic examination revealed that both Core-Vent and Biotes implants achieved osseointegration and maintained the direct contact with bone after 5 months of occlusal loading.     

Relationship between Systemic Bone Mineral Density and Local Bone Quality as Effectors of Dental Implant Survival

Purpose: This study aimed to assess (1) the relationship of systemic bone mineral density (BMD) and osteoporotic status with the surgeon's subjective assessment of local jawbone quality, and (2) whether the surgeon's subjective assessment of local jawbone quality is a predictor of implant failure. Materials and Methods: A retrospective analysis of 2,867 dental implants placed in 645 patients was accomplished. The surgeon's assessment of bone quality at the time of dental implant placement was recorded. Of those, 208 patients with 701 implants had BMD data available within 3 years. Statistical analyses were conducted to determine relationships between BMD, osteoporotic status, and local jawbone quality and to determine the relationship between local jawbone quality and implant survival. Results: There was no association between systemic BMD and the surgeon's assessment of bone quality (p = .52) nor between osteoporotic status and the surgeon's assessment of local jawbone quality (Spearman rank correlation coefficient = 0.08). Additional retrospective analysis revealed implants placed in moderate‐ (hazard ratio = 1.67; p = .043) or poor‐quality (HR = 3.45, p < .001) bone (surgeon's assessment) were significantly more likely to fail than implants placed in good‐quality bone. Conclusion: Systemic BMD and osteoporotic status are not associated with local jawbone quality. Implants placed in good‐quality bone, as assessed subjectively by the surgeon at the time of implant placement, have significantly better survival characteristics than implants placed in moderate‐/poor‐quality bone.     

影响纯钛种植体骨整合界面形成的临床因素分析

目的 通过临床实践探讨影响钝钛种植体骨整合界面形成的因素,寻求防治措施,提高种植义齿的成功率。方法 对230例门诊种植病人采用Branemark纯钛种植体行延期种植术,3～6个月后行Ⅱ期手术。结合X线及术中所见,评价钝钛种植体骨整合界面形成状况。结果 在植入的520颗纯钛种植体中,获得骨整合界面的有503颗,失败17颗,成功率96.7%。结论 影响纯钛种植体骨整合界面形成的因素有术前严格选择适应证及充分的术前准备,防止骨灼烧,预防感染,防止术中种植体被污染。     

Early Healing of Hydroxyapatite‐Coated Implants in Grafted Bone of Zoledronic Acid–Treated Osteoporotic Rabbits

Background: Resorption of grafted bone and delayed osseointegration of implants are main problems associated with alveolar bone augmentation in dental implantology, especially for patients with osteoporosis. The aim of this study is to investigate the early healing response of implants to systemic treatment of zoledronic acid (ZA) in autogenous grafted iliac bone of osteoporotic rabbits. Methods: Ovariectomy (OVX) or sham operation was performed in 46 rabbits, and osteoporotic changes were verified in animals receiving OVX 3 months later. The remaining animals were divided into three groups (n = 12): sham, OVX, and OVX with ZA treatment (ZA group). Autogenous iliac bone grafting was performed in bilateral tibiae, and hydroxyapatite‐coated titanium implants were simultaneously placed into the grafted bone. The animals were sacrificed 2 and 8 weeks later for examination. Results: At both time points, systemic treatment of ZA efficiently promoted bone healing of implants in grafted bone, and all histologic and microcomputed tomography bone indices, including mineralized bone volume, implant–bone contact ratio, connectivity density, trabecular thickness, and trabecular number, were significantly increased in the ZA group compared with the OVX‐only group (P <0.01); implant–bone contact rates in the ZA group were even restored to levels similar to those of sham‐operated animals (P >0.05). Furthermore, biomechanical testing demonstrated that removal torque of implants was significantly increased in the ZA group compared with the OVX group (P <0.01). Conclusion: Systemic treatment with ZA could efficiently promote early bone healing of implants in autogenous grafted bone of osteoporotic rabbits by increasing early osseointegration and fixation of implants.     

Biofunctionalization of titanium implants with a biomimetic active peptide (P‐15) promotes early osseointegration

Objectives: The early stages of peri‐implant bone formation play an essential role in the osseointegration and long‐term success of dental implants. By incorporating bioactive coatings, this biofunctionalization of implant surfaces may enhance the attachment of the implant to the surrounding bone and stimulate bone regeneration. Material and methods: To demonstrate faster osseointegration, the surfaces of dental implants were grit‐blasted and acid‐etched. They were then coated with hydroxyapatite (HA) and experimental implants were further coated with a biomimetic active peptide (P‐15) in one of two concentrations. These biofunctionalized samples and controls with no peptide were placed in the forehead region of 12 adult pigs. Six animals were evaluated for a period of 14 or 30 days. Results: Histomorphometric analysis demonstrated that the implants with the high concentration of P‐15 had significantly higher percentage of bone‐to‐implant contact (BIC) at 14 (P=0.018) and 30 (P=0.015) days compared with the other groups. Both concentrations of P‐15 showed increased peri‐implant bone density compared to the control group at 30 days. Conclusion: Biofunctionalization of the implant surface with a biomimetic active peptide leads to significantly increased BIC rates at 14 and 30 days and higher peri‐implant bone density at 30 days. To cite this article:
Lutz R, Srour S, Nonhoff J, Weisel T, Damien CJ, Schlegel KA. Biofunctionalization of titanium implants with a biomimetic active peptide (P‐15) promotes early osseointegration.
Clin. Oral Impl. Res. 21 , 2010; 726–734.
doi: 10.1111/j.1600‐0501.2009.01904.x     

Research on implants and osseointegration

Osseointegration was originally defined as a direct structural and functional connection between ordered living bone and the surface of a load‐carrying implant. It is now said that an implant is regarded as osseointegrated when there is no progressive relative movement between the implant and the bone with which it is in direct contact. Although the term osseointegration was initially used with reference to titanium metallic implants, the concept is currently applied to all biomaterials that have the ability to osseointegrate. Biomaterials are closely related to the mechanism of osseointegration; these materials are designed to be implanted or incorporated into the living system with the aims to substitute for, or regenerate, tissues and tissue functions. Objective evaluation of the properties of the different biomaterials and of the factors that influence bone repair in general, and at the bone tissue–implant interface, is essential to the clinical success of an implant. The Biomaterials Laboratory of the Oral Pathology Department of the School of Dentistry at the University of Buenos Aires is devoted to the study and research of the properties and biological effects of biomaterials for dental implants and bone substitutes. This paper summarizes the research work resulting from over 25 years’ experience in this field. It includes studies conducted at our laboratory on the local and systemic factors affecting the peri‐implant bone healing process, using experimental models developed by our research team. The results of our research on corrosion, focusing on dental implants, as well as our experience in the evaluation of failed dental implants and bone biopsies obtained following maxillary sinus floor augmentation with bone substitutes, are also reported. Research on biomaterials and their interaction with the biological system is a continuing challenge in biomedicine, which aims to achieve optimal biocompatibility and thus contribute to patient health.     

Histologic analysis of human peri-implant bone in type 1 osteoporosis

Osteoporosis is a disease that influences the quality of bone tissue. At present, osteoporosis represents a contraindication or a risk factor for osseointegration. The aim of this report was to evaluate the bone-to-implant contact of 2 loaded implants retrieved after prosthetic failure in a woman with type 1 osteoporosis. Histologically, only one implant was osseointegrated, and it appeared surrounded by healthy bone tissue. The bone-to-implant contact presented a mean of 51.25%. No foreign body reaction was found at the bone-to-implant contact, although epithelial downgrowth was observed at the interface. Data from this case report demonstrate that the peri-implant bone histology of the dental implant retrieved from an osteoporotic patient presented no alteration. However, the role of osteoporosis in the long-term success of dental implants needs further investigation.     

Clinical outcomes of vertical bone augmentation to enable dental implant placement: a systematic review

Background: This review addressed the focused question of what is the predictability of vertical ridge augmentation techniques for patients, who were diagnosed with insufficient alveolar bone volume for the placement of dental implants.
Material and Methods: A systematic online review of three main databases was performed between 1966 and 1 November 2007. Four groups of vertical bone augmentation techniques have been identified and evaluated: (1) guided bone regeneration, (2) distraction osteogenesis, (3) onlay bone grafting, and (4) an array of different techniques. Data extraction was based on the following outcomes: (a) success and failure rate of the procedure (vertical bone gain/loss), (b) complication rate of the procedure, and (c) implant survival, success and failure rate.
Results: The initial search identified 189 papers from the electronic database. The review produced seven papers for GBR, 13 reporting distraction osteogenesis, five for onlay bone grafting and three describing different techniques.
Conclusions: For the concept of vertical ridge augmentation to enable dental implant placement, there are clinical and histological data supporting its potential use. Given the confined number of investigators using these techniques and the low number of patient treatments reported in the literature, the generalizability of this approach is limited at this time.     

Histomorphometric analyses of bone interface with titanium-aluminum-vanadium and hydroxyapatite-coated implants by biomimetic process

PURPOSE: The surface properties of dental implants have been considered directly related to the success of the osseointegrated interface. Hydroxyapatite (HA)-coated implants promote a bioactive surface because they facilitate cellular migration and bone growth, resulting in a faster osseointegration. MATERIALS AND METHODS: This study analyzed and compared 2 different implant surfaces: a group composed of titanium implants and another group coated with HA. The HA coating was produced by the biomimetic process to reduce costs. RESULTS AND CONCLUSIONS: After histomorphometric analyses it was possible to demonstrate that there were no statistically significant differences between the groups.     

Implant Osseointegration in Circumferential Bone Defects Treated with Latex‐Derived Proteins or Autogenous Bone in Dog's Mandible

Background: In sites with diminished bone volume, the osseointegration of dental implants can be compromised. Innovative biomaterials have been developed to aid successful osseointegration outcomes. Purpose: The aim of this study was to evaluate the osteogenic potential of angiogenic latex proteins for improved bone formation and osseointegration of dental implants. Materials and Methods: Ten dogs were submitted to bilateral circumferential defects (5.0 × 6.3 mm) in the mandible. Dental implant (3.3 × 10.0 mm, TiUnite MK3?, Nobel Biocare AB, Göteborg, Sweden) was installed in the center of the defects. The gap was filled either with coagulum (Cg), autogenous bone graft (BG), or latex angiogenic proteins pool (LPP). Five animals were sacrificed after 4 weeks and 12 weeks, respectively. Implant stability was evaluated using resonance frequency analysis (Osstell Mentor?, Osstell AB, Göteborg, Sweden), and bone formation was analyzed by histological and histometric analysis. Results: LPP showed bone regeneration similar to BG and Cg at 4 weeks and 12 weeks, respectively (p ≥ .05). Bone formation, osseointegration, and implant stability improved significantly from 4 to 12 weeks (p ≤ .05). Conclusion: Based on methodological limitations of this study, Cg alone delivers higher bone formation in the defect as compared with BG at 12 weeks; compared with Cg and BG, the treatment with LPP exhibits no advantage in terms of osteogenic potential in this experimental model, although overall osseointegration was not affected by the treatments employed in this study.     

Histologic and clinical evaluation for maxillary sinus augmentation using macroporous biphasic calcium phosphate in human

Objectives: This study evaluated both the clinical and histological aspects of bone formation in maxillary sinus augmentation using MBCP as the bone-grafting material.
Material and methods: MBCP was used as a primary bone substitute for maxillary sinus augmentation. Fifty-two patients were selected after a medical and dental examination, and were divided into the following three groups: those augmented with MBCP only; MBCP combined with irradiated cancellous bone; and MBCP combined with intraoral autogenous bone. After a healing period (average 6.78 months after surgery), bone cores were harvested for a histological evaluation and the implant fixtures were installed. These bone cores were evaluated via light microscope and implants were followed up for at least six months after loading.
Results: Four to ten months after surgery, new vital bone surrounding the MBCP particles was observed in 18 bone biopsies. Two out of the 130 implants installed were explanted due to a failure of osseointegration before the prosthetic procedure. All the remaining implants were functioning for 6 to 27 months (average 12.96 months). The cumulative survival rate of the implants was 98.46%.
Conclusion: These results show that MBCP can be used as a grafting material for sinus floor augmentation, whether combined with other bone graft materials or not, and lead to a predictable prognosis for dental implants in the posterior maxillary area where there is insufficient vertical height for fixture installation.     

闭合式上颌窦提升术在种植修复中的应用体会

目的 探讨闭合式上颌窦提升术在上颌后牙区骨量不足患者种植修复中的临床疗效。方法 选择我院2009年至2012年上颌后牙区20例牙槽骨高度不足种植患者,采用闭合式上颌窦提升技术,同期植入27颗种植体,随访至少12个月。选择20例条件相近病例,行开放式上颌窦提升同期种植体植入作为对照组。结果 随访期间,26枚种植体均获得了良好的骨结合,种植修复取得了较好的临床效果。1枚种植体二期手术时,被纤维组织包裹,松动。种植体成功率96.30%。实验组植入骨吸收量小于对照组（P＜0.05）。结论 选择合宜的外科操作技巧,在上颌萎缩后牙区采取闭合式上颌窦提升术同期植入种植体的方法能大大缩短患者的治疗时间,取得很高的成功率以及良好的临床效果。     

Clinical report with up to 4 years of follow-up on a cervically modified stepped screw-type implant

PURPOSE: In 1998, a modification of the macrostructure of the Frialit-2 implant in the cervical region was introduced to stabilize peri-implant bone. Limited data are available on the clinical effect of this modification. Therefore, the soft-tissue situation, marginal bone loss, and implant failure rate were analyzed after 4 years of clinical experience with the modified Frialit-2 Synchro implant. MATERIALS AND METHODS: From 1998 to 2001, 190 cervically modified implants were placed and documented prospectively in 58 patients. Of these implants, 147 were placed in original jaw bone, 22 in areas augmented with local osteoplasty, and 21 in iliac crest bone graft. The main indications for implantation were an atrophic edentulous alveolar crest (n = 99) and support for a partial denture (n = 39), followed by restoration of a shortened dental arch (n = 28) and single tooth replacement (n = 24). In a special clinical examination, 39 patients with 134 implants were investigated. RESULTS: The average in situ time of the 134 implants was 23.1 months. Failing osseointegration (n = 10), peri-implantitis (n = 1), and tumor resection (n = 3) in 8 patients resulted in the failure of 14 of 190 implants (7.4%). One patient with 4 implants died (2.1%). Currently, 3 patients with a total of 6 implants have been lost to follow-up (3.1%), and 166 implants remain in situ (87.4% of 190). DISCUSSION: Using different implant success criteria, success rates of 88.8% and 82.8% were calculated. CONCLUSION: Based on the results, the Frialit-2 Synchro implant appears to be a useful implant system for the indications analyzed.     

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...