INDIAN DENTAL JOURNAL

Size: px

Start display at page:

Download "INDIAN DENTAL JOURNAL"

Lionel Carson
5 years ago
Views:

1 SURFACE MODIFICATIONS FOR DENTAL IMPLANTS Dr. Sabzar Abdullah 1 Dr. Syed Wakeel Andrabi 2 Dr. Mahbooba khazir 3 1, 3 Resident, Department of Prosthodontics, Govt Dental College, Srinagar, India 2 Resident, Department of oral and maxillofacial surgeries, Govt Dental College, Srinagar, India Address for Correspondence: Dr. Syed Wakeel Andrabi, Resident, Department of oral and maxillofacial surgeries, Govt Dental College, Srinagar, India syedwakeel12@gmail.com ABSTRACT The use of dental implants is widely increasing now a days to rehabilitate the loss of teeth due to their high success rate and less number of complications. The surface of titanium implants is modified in a large number of ways to enhance the process of osseointegration. These modifications include roughening of the implant surface by sandblasting and acid etching, anodic oxidation, fluoride treatment, and calcium phosphate coating. Such modified surfaces demonstrate faster and stronger osseointegration than the turned commercially pure titanium surface. This article reviews the different surface modifications and the results of few studies. KEYWORDS: Osseointegration, Primary Stability, Dental Implant, Bioactive Surface Modification I NTRODUCTION - One of the most important factors in the process of osseointegration is surface roughness, which shows increased osteoblast activity at 1 to 100 μm of the surface roughness compared to a smooth surface 1 it is believed that rough surfaces show better osseointegration than the smooth surfaces however studies show diverse results. Various theories have been proposed in the past years which attribute the success of dental implants.one of the most important is the theory of Branemark.he defined osseointegration at a light microscopic level as a direct structural and functional connection between ordered living bone and surface of a load carrying implant.various factors contribute to the success of dental implants like implant factors, local or anatomic factors, biologic factors, systemic or functional factors.the characteristics or the alterations of the implant surface are an important factor which affects the rate and extent of osseointegration.the surface of the implant affects the connection formed between the bone and the implant and also fastens the rate of osseointegration. Different methods are used to modify the surface of dental implants to achieve high success rates and better osseointegration. Macrotopography, microtopography and nanotopography are the three categories under which the different surface modifications are studied.the edentulous period of a patient can be shortened by fastening the process of osseointegration and this can be done by modification of the Ti surface 2. There are various methods by which surface roughness can be increased such as as machining, plasma spray coating, grit blasting, acid etching, sandblasted and acid etching (SLA), anodizing, and biomimetic coating. These different modifications are used to improve the biological surface properties favoring osseointegration 3. 15

2 The turned or machined implants are the first generation of implants. They have a relatively smooth surface. These are known to be smooth inadequately as the SEM ANALYSIS shows that they have grooves, ridges and marks derived from tools used for their manufacturing which provides mechanical resistance through bone interlocking 4. However, their main disadvantage is that they require long healing time and they have low resistance to removal torque. Grit-blasting is another method used for roughening of the implant surface.it is usually done by using silica (sand), alumina, titanium dioxide or resorbable bioceramics such as calcium phosphate.it leads to different surf roughness depending on the size of the used ceramic particles that are projected through a nozzle at high velocity by means of compressed air and leading to different surface roughness, depending on the size of the ceramic particles 5. Alumina (Al2O3) is frequently used as a blasting material, however, it is often embedded into the implant surface and residue remains even after ultrasonic cleaning, acid passivation and sterilization. It has been documented that these particles have been released into the surrounding tissues and interfered with the osteointegration of the implants 6. Another method which results in homogenous roughness is acid etching.in this methods, implants are immersed in strong acids such as hydrochloric acid, sulfuric acid,nitric acid and hydrogen fluoride.it produces micropits on the Ti surfaces with sizes ranging from 0.5 to 2 μm in diameter.it improves adhesion of the osteoblastic cells and increases the active surface area..some studies have proposed that hydrogen embrittlement can lead to formation of microcracks on the surface. Acid etching and surface coatings of the implant are the most preferred methods for roughening of the implant surface 7. Both the topography as well as the chemistry of an implant surface 8 are affected by modification of the surface by different surface treatments. The roughened surfaces have shown higher bone contact, better bone responses and superior histomorphometry as compared to turned surfaces 9 In an experiment it was reported that the implant surface that are acid etched show nearly four times greater resistance to removal torque 10. In a study it was described that new bone was grown from the sandblasted surface to the old bone, while the bone was formed from the old bone to the turned surface 11. Similar results have been shown by the plasma etched surfaces however they are no better than surface topographies created by sand blasting or acid etching 12. Anodization is basically passivation of the surface with the action of an electric current.it results in much thicker oxide layer formation.it is the dielectric breakdown of the TiO2 layer by applying an increased voltage to generate a micro-arc resulting in the formation of a porous layer on the titanium surface 13. These type of implants are placed as anodes in galvanic cells using phosphoric acid is used as the electrolyte and current is passed through them. The surface oxides grow from the native state of 5nm to approximately 10,000nm 14 It is important for highly roughened surfaces, as the increased surface area has the potential for greater release of metallic ions in phosphoric acid as electrolyte into the surrounding tissue.it increases the roughness as well as the thickness of the oxide layer formation. These factors are important for the biological bone response and thus these type of implants show more favorable responses than the turned smooth 16

3 Ti surfaces. Which results in better biological response 15. Titanium plasma-spraying (TPS) is another method for roughening of the implant surface. The Ti particles are injected into the plasma torch at high temperature and are then projected to form a film of 30 μm thick resulting in an average roughness of around 7 μm 16 it increases the surface area by about six times the initial surface area.and is dependent on implant geometry and processing variables, such as initial powder size, plasma temperature, and distance between the nozzle output and target. The delamination and failure at the implantcoating interface of the coating from the surface of the titanium implant are the major concerns in it. Besides the physical methods used for surface modifications of implant surface there are some chemical methods too which are considered to make osseointegration stronger than the roughened surfaces. Since 1980s calcium phosphate coated surfaces have been used as they have properties 17 similar to the bone mineral. Hydroxyapatite is also used as a coating material consisting of amorphous and crystalline forms. The later ones are found to be more superior comparatively with respect to the bone implant contact. Hydroxyapatite (HA) is a very stable biological form of CaP and strengthens the organic matrix by mineralization. HA coatings resemble a reservoir of calcium and phosphate in addition to their biomimetic property. A HA coated implant surface roughness, sa of 3.29± 1.5µm has been reported 18. The novel modes of application of HA resulted in much thinner HA layers than those which were used previously, when plasma was sprayed with a minimum coating of 50µm thickness. The modern HA applications of 1µm or nanometre thickness have reduced the risk of loosening of the implant from the surface. Hydroxyapatite or tribasic calcium phosphate has largely eclipsed tricalcium phosphate coated implants 19. Ha coating on the implant surface (50-70µm) can be done by various methods: 1. PLASMA SPRAYING 2. VACUUM DEPOSITION 3. SOL GEL AND DIP COATING METHOD 4. ELECTROLYTIC PROCESS The HA coating is considered to be superior than sandblasted SLA, TPS, and/or machined surfaces in bone-implant contact ratio according to a study 20. However there were no significant differences among them according to another study 21. Nanotechnology is also finding applications in modification of the implant surfaces. Numerous techniques are used to create nanofeatures on the Ti implant surfaces like Ceramic coating, physical approaches like plasma spraying, ion deposition, chemical methods like acid and alkali treatment and anodization, a combination of chemical etching and anodization etc. These different methods enhance the surface characteristics thereby resulting in faster bone healing and rapid osseointegration.however it is still in stage of advancement and requires much more testing before appreciating its maximum potential in implant dentistry 22 CONCLUSION A surface modification of implant is an important aspect in implant dentistry. These modifications enhance the rates of osseointegration and thus results in faster and stronger bone response. Many experiments both invivo and invitro have been conducted and further studies are still needed. 17

4 REFERENCES 1. Jenny G, Jauernik J, Bierbaum S, Bigler M, Gratz KW, Rucker M, Stadlinger B (2016) A systematic review and meta-analysis on the influence of biological implant surface coatings on periimplant bone formation. J Biomed MaterRes A 104: J. E. Ellingsen, "Surface configurations of dental implants", Periodontol. 2000, vol. 17, pp , June L. F. Cooper, "A role for surface topography in creating and maintaining bone at titanium endosseous implants," J. Prosthet. Dent., vol. 84, pp , Nov J. E. Ellingsen, "Surface configurations of dental implants", Periodontol. 2000, vol. 17, pp , June A. Wennerberg and T. Albrektsson, "Effects of titanium surface topography on bone integration: a systematic review," Clin. Oral Implants Res., vol. 20, Suppl 4, pp , Sep A. Wennerberg and T. Albrektsson, "On implant surfaces: a review of current knowledge and opinions," Int. J. Oral Maxillofac. Implants, vol. 25, pp , Jan.-Feb Smeets R, Stadlinger B, Schwarz F, Beck-Broichsitter B, Jung O, Precht C, Kloss F, Grobe A, Heiland M, Ebker T (2016) Impact of dental implant surface modifications on osseointegration. Biomed Res Int 2016: Jemat A, Ghazali MJ, Razali M, Otsuka Y (2015) Surface modifications and their effects on titanium dental implants. Biomed Res Int 2015: von Wilmowsky C, Moest T, Nkenke E, Stelzle F, Schlegel KA (2014) Implants in bone: part I. A current overview about tissue response, surface modifications and future perspectives. Oral Maxillofac Surg 18: Barfeie A, Wilson J, Rees J (2015) Implant surface characteristics and their effect on osseointegration. Br Dent J 218:E Branemark PI, A.R., Breine U, Hansson BO, Lindstrom J, Ohlsson A., Intraosseous anchorage of dental prostheses. I. Experimental studies. Scand J PlastReconstrSurg, : p AlfarrajAldosari, A., et al., The Influence of implant geometry and surface composition on bone response. Clin Oral Implants Res, Le Guehennec, L., et al., Osteoblastic cell behaviour on different titanium implant surfaces. ActaBiomater, (3): p Barfeie A, Wilson J, Rees J (2015) Implant surface characteristics and their effect on osseointegration. Br Dent J 218:E Braceras, I., et al., In vivo low-density bone apposition on different implant surface materials. Int J Oral MaxillofacSurg, (3): p P. R. Klokkevold, R. D. Nishimura, M. Adachi, and A. Caputo, "Osseointegration enhanced by chemical etching of the titanium surface. A torque removal study in the rabbit," Clin. Oral Implants Res., vol. 8, pp , Dec A. Piattelli, L. Manzon, A. Scarano, M. Paolantonio, and M. Piattelli, 18

5 "Histologic and histomorphometric analysis of the bone response to machined and sandblasted titanium implants: an experimental study in rabbits", Int. J. Oral Maxillofac. Implants, vol. 13, pp , Nov.- Dec I. S. Yeo, J. S. Han, and J. H. Yang, "Biomechanical and histomorphometric study of dental implants with different surface characteristics," J. Biomed. Mater. Res. B Appl. Biomater., vol. 87, pp , Nov Pieles U., T.Bühler, B von Rechenberg, K. Voelter, D.Snetivy, F. Schlottig, Investigation of a unique nanostructured dental implant surface, European Cells and Materials, 14 (Suppl. 3), 95 (2007). 20. Li LH, Kong YM, Kim HW, Kim YW, Kim HE, Heo SJ, Koak JY (2004) Improved biological performance of Ti implants due to surface modification by microarc. 21. Wennerberg A, Albrektsson T. On implant surfaces: A review of the current knowledge and opinions. Int J Oral Maxillofac Implants 2010;25(1): I. S. Yeo, J. S. Han, and J. H. Yang, "Biomechanical and histomorphometric study of dental implants with different surface characteristics," J. Biomed. Mater. Res. B Appl. Biomater., vol. 87, pp , Nov

Titanium dental implant surfaces

ISSN 1517-7076 Revista Matéria, v. 15, n. 2, pp. 138 142, 2010. http://www.materia.coppe.ufrj.br/sarra/artigos/artigo11207 ABSTRACT Titanium dental implant surfaces Carlos Nelson Elias Laboratório de Biomateriais-