The journal of PROSTHETIC AND IMPLANT DENTISTRY Official Publication of Indian Prosthodontic Society Kerala State Branch BIOCERAMICS:

*Rohit Raghavan, **Shajahan P A, ***Poornima Purushothaman

* Head of the Department, **Professor, ***Post Graduate Student, Department of Prosthodontics and Crown and Bridge, Royal Dental College; Chalissery | Corresponding Author: Dr. Poornima Purushothaman, E-mail: [email protected]

suitable for inclusion in systems which augment or Abstract: replace the function of bodily tissues or organs.” Bioimplants are prosthesis made for regularising Bioceramics are an important subset of biomaterials the physiological function of body and bioceramics which act as an excellent substitute which is represent one classification of the bio implant been used in many fields of medicine. Bioceramics based on the material used. range in their biocompatibility from the , which are bioinert, to the other extreme of bioresorbable materials, which are eventually HISTORY replaced by the body after they have assisted the Plaster of Paris (CaSO .H O) – first widely evaluated repair of cells. Its application in dental implants has 4 2 bioceramic gained interest in the past two decades. This review is attempted to emphasize the approaches done in 1892—Dressman published first report on the use bioceramic materials for use in dental implants. of plaster of Paris to repair bone defect.

1920—first successful use of Tricalcium phosphate

Keywords: Bio , zirconium, 1930—polymeric implants introduced (Rock 1933- bioimplants alumina) 1960s—1970s – interest in bioceramic invention INTRODUCTION by work of Hulbert and co-worker. The efforts to restore completely and partially 1969-1971—bioactive glass ceramic first introduced edentulous arches have been practiced by by L.L Hench. clinicians since centuries. By the introduction of 1988—plasma sprayed hydroxyapatite first used dental implants it has become the mainstream by Herman practice and is clinically accepted as the desired treatment modality for the patients. Implant IMPLANT SELECTION biomaterials, especially bioceramics have provided GUIDELINES the research and dental clinical professionals with a new essence of interest for over past two decades. The American dental association outlines some acceptance guidelines for dental implant Biomaterial by definition is a “non-drug substance biomaterials:

32 / JPID – The journal of Prosthetic and Implant Dentistry / Volume 4 Issue 1 / September–December 2020 The journal of Bioceramics: dental implant biomaterials PROSTHETIC AND IMPLANT DENTISTRY Official Publication of Indian Prosthodontic Society Kerala State Branch

1. The evaluation of physical properties that 5. At least two independent longitudinal prospective ensure sufficient strength; clinical studies demonstrating efficacy.

2. Demonstration of ease of fabrication and CLASSIFICATION OF BIOCERAMICS sterilization potential without material degradation; Ceramics used for the repair and reconstruction of 3. Safety & biocompatibility evaluation, diseased or damaged parts of the musculoskeletal including cytotoxicity testing & tissue interference system termed as bioceramics, maybe categorized characteristics; as follows: 4. Freedom from defects;

1. Based on tissue reaction

BIOACTIVE Material which upon being placed Eg: Synthetic hydroxyapatite, bioglass, within the human body interact with apatite-wollastonite glass ceramic. surrounding bone and soft tissues. BIOINERT Material once placed in the human Eg: Titanium, zirconia, alumina, stainless body has minimal interaction with its steel, carbon and carbon silicon compounds surrounding tissue. BIORESORBABLE Material upon placement with the Eg: Tricalcium phosphate, polylactic- human body starts to dissolve and polyglycolic acid copolymers, calcium slowly replaced by advancing , calcium carbonate and gypsum tissue(bone)

2. Based on tissue attachment

1. Morphologic fixation 2. Biological fixation 3. Bioactive fixation 4. Bioresorbable Dense, non-porous, Porous inert implants Dense, non-porous, Dense, non-porous or nearly inert ceramics has bone ingrowth which surface reactive porous resorbable that attach by bone mechanically attaches ceramics, glasses and ceramics are designed growth into the surface bone to material glass-ceramics attach to be slowly replaced irregularities. It can be directly by chemical by the bone. either cementing into bonding with bone. tissue /press fitting into a defect. Eg: aluminium Eg: Eg: bioactive Eg: calcium sulphate, oxide(single crystal (porous polycrystalline), glass, bioactive tricalcium phosphate and polycrystalline) Hydroxyapatite coated glass-ceramics, porous metals Hydroxyapatite

JPID – The journal of Prosthetic and Implant Dentistry / Volume 4 Issue 1 / September–December 2020 / 33 The journal of Rohit Raghavan, Shajahan P A, Poornima Purushothaman PROSTHETIC AND IMPLANT DENTISTRY Official Publication of Indian Prosthodontic Society Kerala State Branch

BIOACTIVE CERAMICS as a foreign material and attempts to isolate it by forming a non adherent fibrous layer which Bioglass / Glass Ceramics: is considered as a drawback in the use of this material. Discovery of Bioglass was by Hench and Wilson. It was first introduced in the year 1971. The glasses containing specific proportions of silica, sodium Titanium: oxide, calcium oxide and phosphorus pentoxide Titanium was first introduced in the year 1789 are termed bioactive. The nucleation and growth by Wilhelm Gregor. Due its excellent property of crystals within the glass converts the glass to of biocompatibility and its ability to form stable glass ceramics, which retain the bioactivity. They oxides it has been successfully used as an implant have high mechanical strength, fast setting ability, material in the recent years. Three different oxides low resistance to tensile and bending stresses and formed on titanium surface are TiO (Anastase), extreme brittleness. They chemically bond to bone TiO2 (Rutile) and Ti2O3 (Brookite). due to formation of calcium phosphate surface Titanium oxide layer exhibits low level of charge layer. Ceravital silica is a type of glass ceramic. transfer. Its modulus of elasticity of is half of the other alloys 5 to 5.6 times greater than bone that Hydroxyapaptite: helps in its uniform stress distribution. It is chemically calcium phosphate [Ca (PO ) 10 4 6 Zirconia: (OH)2 ]and is similar to the mineral component of and hard tissues. Hydroxyapatite was was first extracted from the successfully used as an implant material in 1988 mineral Zircon (Zirconium Silicate ZrSiO4) by soon after the bioactive glasses were developed. the German chemist Martin Heinrich Klaproth The hydroxyapatite in powder form is excellent (1743-1817). It was in 1969 the first scientific study bone filler. They have calcium to phosphorus of outstanding biomedical properties of zirconia ratio of 1.67 and is the most stable phase of emerged and subsequently it was found that various calcium phosphates. The preparations alloying zirconia with oxides of yttria, calcia and of hydroxyapatite powders include wet methods magnesia made it stable. This discovery also led to and solid state reactions. Hydroxyapatite is stable the use of the so-called transformation toughening in body fluid and in dry or moist air upto 12000C of zirconia to produce ceramics with unsurpassed and does not decompose. crack resistance (‘ceramic steel’). Plasma sprayed hydoxyapatite was first used Zirconia was successfully used as implant material by HERMAN in 1988. It is used as coatings on in 1960s. It has high flexural strength, fracture implants. toughness and ability to be polished to a superior surface than alumina. Zirconia implants also BIOINERT: absorb water and hence become prone to fracture. Yttrium stabilised tetragonal polycrystalline Alumina: zirconia: Alumina is a highly inert material which was This form of zirconia offers best mechanical introduced by Rock in 1933. It was first used as an properties. implant material in the 1970s. It has excellent wear resistance and surface hardness. Alumina exists Carbon and carbon silicon in many forms and these arise during the heat compounds: treatment of aluminium hydroxide or aluminium Vitreous carbon and carbon compounds are used oxy hydroxide. However the body recognises it in implantology since 1970. Carbon is a versatile

34 / JPID – The journal of Prosthetic and Implant Dentistry / Volume 4 Issue 1 / September–December 2020 The journal of Bioceramics: dental implant biomaterials PROSTHETIC AND IMPLANT DENTISTRY Official Publication of Indian Prosthodontic Society Kerala State Branch that exists in many forms. The biocompatibility Basel, Switzerland) has recently been introduced of carbonaceous material to bone indicates its in dentistry. This alloy which has a metallic gray use in orthopaedic implants. However due to the appearance contains 83-87% titanium and intrinsic brittleness and low tensile strength, carbon 13-17% zirconium. It has superior mechanical compounds have limitations for use in major load characteristics over commercially pure (CpTi) and bearing applications. Ti-6Al-4V, as well as increased fatigue strength.

BIORESORBABLE: The addition of zirconia to titanium leads to excellent osseointegration capabilities. The Calcium phosphate ceramics: biocompatibility of titanium-zirconium alloy is also more when compared to pure titanium. Calcium phosphate ceramics was first commercially In order to maintain the clean oxide layer with used as implant material in 1980s. They have its hydrophilic properties the Titanium-Zirconium biochemical composition similar to bone and implants are manufactured with the SLActive exhibit direct chemical bonding to surrounding surface like the titanium SLActive implants: Sand bone. Therefore they are used as implant material blasted, acid etched and then stored in 0.9% NaCl to be gradually substituted by newly formed bone solution. and get integrated with the host bone. The first stage is interaction with collagen in bone and Polyetheretherketone (PEEK) then accumulation of protein and cells on the surface of the biomaterial and this is followed by For patients with high aesthetic requirements, the resorption of the material and finally bone the new material known as PEEK (polyether ether formation. ketone) is recommended as it is aesthetic, stable, biocompatible, lighter degree of discoloration. A subclass of these ceramics is tricalcium BioHPP (High Performance Polymer) is based phosphate ceramics. They are extensively used on polyether-ether-ketone (PEEK) polymer and owing to its biocompatibility characteristics. was introduced as dental material for precise They also have an added advantage of being prosthetic restoration fabrication. BioHPP has a resorbable. low specific weight that permits the fabrication Other calcium phosphate compounds include: of lighter prostheses which provides high patient satisfaction and comfort during masticatory -Amorphous calcium phosphate (ACP) function.

-Dicalcium phosphate (DCP) BioHPP reduces the stress caused by natural -Pentacalcium hydroxyapatite forces as well as the forces attributed to the prosthetic restorations. While comparing with -Tetracalcium Phosphate Monoxide (TTCP) titanium, zirconium or ceramic, rehabilitation using BioHPP significantly reduces the peak masticatory NEW DEVELOPMENTS IN forces both for axial and oblique movements. This BIOCERAMIC IMPLANT MATERIALS: property provides a positive effect for the patient and also it extends the durability of the restoration. Titanium-Zirconium alloy (Straumann ROXOLID) Silicon nitride (Si3N4) ceramics Narrow diameter implants (Roxolid®, Straumann, Titanium has been the choice for dental implant

JPID – The journal of Prosthetic and Implant Dentistry / Volume 4 Issue 1 / September–December 2020 / 35 The journal of Rohit Raghavan, Shajahan P A, Poornima Purushothaman PROSTHETIC AND IMPLANT DENTISTRY Official Publication of Indian Prosthodontic Society Kerala State Branch

fabrication for many years owing to its superior nitride have given way for more future research mechanical and biological performances. The which could be of great interest for oral use. increasing demand for metal-free restorations has led to development of ceramic-based implants REFERENCES like Zirconia and other alternative biomaterials 1. Misch CE. Contemporary Implant Dentistry. 3rd ed. St. like PEEK and silicon nitride. Louis, USA: Mosby; 1999 -2011. p. 511-36 Silicon nitride has following properties: 2. Denry I, Kelly JR. State of the art of zirconia for dental applications. Dent Mater. 2008;24(3):299–307. w Excellent antibacterial properties 3. Hegde C, Krishna Prasad D, Deepmala S, Rakshith Hegde. Implant restoration materials: An overview. w Biocompatible and biologically inert International Journal of Oral Implantology and Clinical w High flexural strength Research 2010;1:43-8 4. Karan M, Dua JS, Chawla S, et al: Poly-etheretherketone w High fracture resistance (PEEK) dental implants: a case for immediate loading. w Excellent wettability to biologic fluids Int J Oral Implantol Clin Res 2011;2:97-103 w High wear resistance 5. Chauhan CJ, Shah DN, Patel R. Evolution of biomaterials in dental implants part-2. JADCH 2011;2:2-5. Silicon nitride derives its strength and toughness 6. Muddugangadhar BC, Amarnath GS, Tripathi S, Divya through its microstructure, which is mainly SD. Biomaterials for dental implants: An overview. Int J Oral Implantology Clin Res 2011-2:13-24. composed of asymmetric needle-like interlocking 7. Schwitalla A, Muller WD: PEEK dental implants: a review grains surrounded by a thin (<2mm) refractory of the literature. J Oral Implantol 2013;39:743-749 grain-boundary glass. Unlike other ceramics, there 8. Shrestha S, Joshi S. Current concepts in biomaterials is no phase transformation is involved. in dental implant. Science Research 2014;2:7-12. 9. Saini M, Singh Y, Arora P, Arora V, Jain K. Implant CONCLUSION biomaterials: A comprehensive review. World J Clin Cases 2015;3:52-7. The primary requisite for a dental implant 10. Duraccio D, Mussano F, Faga MG. Biomaterials for material is to be biocompatible and have dental implants: current and future trends. J Mater Sci. 2015;50:4779–812. superior biomechanical properties. Various 11. Prakasam M, Locs J, Salma-Ancane K, Loca D, Largateau implant biomaterials like titanium, zirconia, etc A, Berzina-Cimdina L. Biodegradable materials and are used in this aspect which provides excellent metallic implants- A review. J. Funct. Biomater.2017,8,44. osseointegration with the bone. The recent 12. Deepashree R, Devaki V, Kandhasamy B, Ajay R. Evolution developments in biomaterials having high esthetic of implant biomaterials: A literature review. Journal of Indian Academy of Dental Specialist Researchers performance like polyetheretherketone and silicon 2017;4:65-7.

36 / JPID – The journal of Prosthetic and Implant Dentistry / Volume 4 Issue 1 / September–December 2020