COMPARATIVE EVALUATION OF THE PUSH-OUT BOND STRENGTH OF GLASS FIBER REINFORCED COMPOSITE RESIN POST AND MODIFIED POLYETHERETHERKETONE
(PEEK) POST FOLLOWING SURFACE TREATMENTS – AN IN VITRO STUDY
Dissertation Submitted to
THE TAMILNADU Dr. M.G.R. MEDICAL UNIVERSITY
In partial fulfilment for the Degree of
MASTER OF DENTAL SURGERY
BRANCH I
PROSTHODONTICS AND CROWN & BRIDGE
MAY 2019
ACKNOWLEDGEMENT
First and foremost, I would like to thank God Almighty for giving me the strength, knowledge, ability and opportunity to undertake this research study and to persevere and complete it satisfactorily. Without his blessings, this achievement would not have been possible.
This dissertation is the result of work with immense support from many people and it is a pleasure now that I have the opportunity to express my gratitude to all of them.
I would like to express my sincere gratitude to Professor Dr. N.S. AZHAGARASAN M.D.S., Principal & Head, Department of
Prosthodontics and Crown & Bridge for the continuous support of my study &
research, for his patience, motivation, enthusiasm and immense knowledge.
My sincere gratitude also goes to Professor Dr. K. Chitra Shankar M.D.S., whom I have come to admire and would love to follow her way of professionalism in the field of academics. Her encouragement, insightful comments and hard questions always kept me on my toes to hunt for answers and learn from it.
I have great pleasure in acknowledging my Guide, Dr. Hariharan Ramakrishnan M.D.S., PGDHM, AFLD for the heartfelt support
and guidance. He has given me all the freedom to purse my research, while silently and non-obtrusively ensuring that I stay on course and do not deviate from the core of my research.
I am also deeply thankful to my Professor Dr. S. Jayakrishnakumar, M.D.S., for his critics, doubts and questions in the field of my study, which always kept me on vigil and corrects my mistakes and succeed in my research.
I would like to extend my thanks to those who offered guidance and support over the years: Dr. M. Saravanakumar, M.D.S., Professor,Dr. R.
Hariharan, M.D.S., Reader Dr. J. Vidhya, M.D.S., Reader Dr. Vallabh Mahadevan, M.D.S., Reader Dr. Shameem, M.D.S., Dr. Manoj Kumar, M.D.S., Dr. Mahadevan, M.D.S., Dr. Kamakshi, M.D.S
I would like to extend my thanks to Prof & Head of the department Dr.
K. Mahendranadh Reddy, M.D.S., for his valuable, amazing and timely support in his dental clinic and lab for my study.
I am so grateful to Dr. Vijaya Nirmala, M.D.S., and Mrs. Yuvarani Department of oral and maxillofacial pathology, SRI RAMACHANDRA DENTAL COLLEGE for helping me in sectioning of the samples.
I take this opportunity to acknowledge and thank Mr. Sateeshkumar and Mr. Ramkumar, OMEGA INSPECTION AND ANALYTICAL LAB, Chennai for providing me with necessary equipments for my study.
I am thankful to Mr. Tamizh who helped me with optical microscope images es of my study samples.
I would like to thank Dr. Ravanan, Principal, Presidency College, for helping me with the statistical analysis of this study.
I take this opportunity to thank Mr. K. Thavamani, Scribbles for helping me with all the printouts and binding of my months’ work into presentable books.
I would like to thank my friends and well-wishers Dr. Pavithra M.D.S., Mr. Ajay, Mr. Rajesh kumar, Dr. Devi, Mr. Sathya, Dr. Archana, Dr. Akila V, Dr. Kishok, Dr. Manojkumar, Ms. Nisha for their support and help during my post-graduation.
My journey in this field of dentistry would not have begun without the support of my parents Mr. B. C. Pullaiah and Mrs. B. Pushpa latha. Am indebted to them throughout my life. Without their love and support I would not be able to stand where I am now. They picked and dusted me up whenever I fell, encouraged me to move forward and stood tall beside me when the whole world
was against me. Simple note of acknowledgement is not enough for the most precious things they did to me. Am more than grateful for them.
In my heart and mind, I have been blessed with the good fortune of having sisters Mrs. Jyothi and Ms. Gayathri to be my side for a lifetime. Though they were younger by birth still they both funded to all my thesis work. They supported me when I couldn’t stand, believed in me in whatever I chose to do, protected me from all the evils.
Special thanks to my junior Dr. K. Aishwariya who helped me with the photographs and articles of my thesis work.
It would be inappropriate if I omit to mention the names of all my seniors, juniors and my colleagues Dr. Ambedkar, Dr. Pavankumar, Dr. R. Sethuraman, Dr. Sherin Grace Babu, Dr. Arul Kumar, Dr. Chaturya Konda, Dr.
Mahalakshmi, Dr. Revathy, Dr. Abinaya Sekar, Dr. Janani D, Dr. GU Ashwini Sukanya, Dr. A. Gayathree, Dr. T. Priyadarshini, Dr. Manimala Murthy, Dr. R.
Maniamudhu, Dr. Asish M, Dr. Jensy Sara George, Dr. Samin, Dr. K.
Aishwariya, Dr. S.Yasmin Fathima, Dr. Surabhi Halder, Dr. Kavya, Dr.
Tejaswi, Dr. Vaishali, Dr. Shivashankari for their continuous support throughout my post graduate course.
CONTENTS
S.NO TITLE PAGE NO.
1. INTRODUCTION 1
2. REVIEW OF LITERATURE 7
3. MATERIALS AND METHODS 28
4. RESULTS 47
5. DISCUSSION 62
6. CONCLUSION 69
7. SUMMARY 72
8. BIBLIOGRAPHY 75
LIST OF TABLES
TABLE No. TITLE PAGE No.
I. The Basic and mean push out bond strength values 50 of prefabricated glass fiber reinforced composite
resin post in coronal, middle, and apical regions.
II. The Basic and mean push out bond strength values 51 of customized modified PEEK post in coronal,
middle, and apical regions.
III. Comparison of push out bond strength of prefabricated 52 glass fiber reinforced composite resin post and
customized modified PEEK post in coronal region
IV. Comparison of push out bond strength of 53 Prefabricated glass fiber reinforced composite resin post
And customized modified PEEK post in middle region
V. Comparison of push out bond strength of 54 Prefabricated glass fiber reinforced composite resin post
And customized modified PEEK post in apical region.
VI. Overall comparison of mean push out bond strength of 55 Prefabricated glass fiber reinforced composite resin post
And customized modified PEEK post.
VII. Mode of failure for prefabricated glass fiber reinforced 56 composite resin post.
VIII. Mode of failure for customized modified PEEK post. 57
IX. Overall comparison of mode of failure for 58 Prefabricated glass fiber reinforced composite resin post
And customized modified PEEK post
ANNEXURE I
METHODOLOGY OVERVIEW ANNEXURE II
LIST OF FIGURES FIG. No. TITLE
Fig. 1: Extracted mandibular first premolars (n=30) Fig. 2: High speed airotor handpiece
Fig. 3: Diamond disc for decoronation
Fig. 4: Materials used for mounting and embedding the samples Fig. 4a: Addition silicone impression material
Fig. 4b: Tooth coloured self cure acrylic resin powder and liquid monomer Fig. 4c: Arkansas stone
Fig. 4d: 5 ml disposable Syringe
Fig. 5: Armamentarium for root canal treatment Fig. 5a: X mart endomotor
Fig. 5b: Stainless steel k files
Fig. 5c: Rotary endo files Fig. 5d: 17% EDTA
Fig. 5e: Rc-seal root canal sealer Fig. 5f: 3% sodium hypochlorite Fig. 5g: 0.9% saline
Fig. 5h: 2.5ml disposable syringe Fig. 5i: Gutta percha (6%) Fig. 6: Distilled water
Fig. 7: Post space preparation armamentarium Fig. 7a: Micro motor and handpiece
Fig. 7b: Peeso reamers
Fig. 7c: Reforpost post space drill
Fig. 8: Glass fiber reinforced composite resin post-1.5mm Diameter Fig. 9: Wax pattern armamentarium
Fig. 9a: Dental inlay casting wax
Fig. 9b: Wooden tooth picks Fig. 9c: Isolating Liquid Fig. 9d: P.K.T instruments Fig. 10: Spruing wax
Fig. 11: Deguvest powder and liquid investment material Fig. 12: BioHPP PEEK granules
Fig. 13: Customized PEEK post sample Fig. 14: Alumina particles (50µm size) Fig. 15: Silane coating armamentarium Fig. 15a: Silane coupling agent
Fig. 15b: Applicator tips
Fig. 16: Post cementation armamentarium Fig. 16a: Maxcem elite dual-cure resin cement Fig. 16b: Intra canal tips
Fig. 17: PEEK burnout furnace
Fig. 18: PEEK Vacuum press device Fig. 19: Sandblaster
Fig. 20: Light curing unit Fig. 21: Hard tissue microtome Fig. 22: Universal testing machine Fig. 23: Optical microscope
Fig. 24: Preservation of teeth in 0.9% saline (n=30) Fig. 25: Decoronation of the teeth samples
Fig. 26: Embeded samples in self-cure acrylic resin Fig. 27: Working length determination x-ray Fig. 28: Master cone x-ray
Fig. 29: Obturated sample x-ray
Fig. 30: Post space preparation sample x-ray Fig. 31: Sandblasting the glass fiber post
Fig. 32: Application of silane coupling agent on glass fiber post
Fig. 33: Dual cure resin cement placement into the post space of fiber post Fig. 34: Light curing the glass fiber post
Fig. 35: Wax pattern for PEEK post
Fig. 36: Spruing of wax pattern to crucible former Fig. 37: Investment of the wax pattern
Fig. 38: PEEK burn out procedure in furnace Fig. 39: Placement of PEEK granules in investment Fig. 40: PEEK pressing into investment
Fig. 41: Sandblasting the PEEK post
Fig. 42: Application of silane coupling agent on PEEK post
Fig. 43: Dual cure resin cement placement into the post space of PEEK post
Fig. 44: Light curing the PEEK post
Fig. 45: Sectioning of the samples in hard tissue microtome Fig. 46: Sectioned samples at coronal, middle, apical
Fig. 47: Custom made stain less steel platform for push out test
Fig. 48: Load application on the sample in UTM Fig. 49: Mode of failure assessment in test sample
ANNEXURE III LIST OF GRAPHS GRAPH No. TITLE
I. Over all comparison of mean push out bond strength of prefabricated glass fiber reinforced composite resin post and customized modified peek post
II. Mode of failure of prefabricated glass fiber reinforced composite resin post
III. Mode of failure of customized modified peek post
ANNEXURE IV
OPTICAL MICROSCOPE IMAGES OF MODE OF FAILURE
IMAGE No. TITLE
Fig. 50: Adhesive Mode of failure image of glass fiber reinforced composite resin post in coronal region
Fig. 51: Adhesive Mode of failure image of customized modified PEEK post in coronal region
ANNEXURE V
PLAGIARISM REPORT
Introduction
1
INTRODUCTION
Root canal treatment is broadly performed on teeth evidently affected by deep caries, multiple repeat restorations and/or fracture. It involves the removal of necrotic and infected pulp tissue followed by a well condensed obturation to prevent further microbial proliferation within the canal system.16
However, the long term clinical success of root canal treatment relays on efficient post endodontic restoration which prevent bacterial recontamination of the root canal system from the oral fluids.29
Several researches had proposed that the dentin in root canal treated teeth is appreciably different than dentin in teeth with vital pulps, where a protective feedback mechanism is lost when the pulp is removed and roots are more prone to fracture.65, 71
Endodontically treated teeth with greater coronal damage are restored with posts and cores so that it can reinforce its form and function.
The fundamental rationale of an endodontic post is to retain the coronal restoration in a root canal treated tooth that has endured an extensive loss of crown structure because of decay, excessive wear or old restoration.71 A variety of materials have been used for posts ranging from wooden posts of the 18th-century to metallic posts made of precious or nonprecious casting alloys and, more recently, carbon fiber, glass fiber, poly ethylene fiber, ceramic and zirconia posts. Endodontic posts are available as active or passive posts, parallel or tapered, custom made or prefabricated.69
2
Generally active posts are threaded and are anticipated to engage the walls of the canal, whereas passive posts are retained firmly by the luting agent. Active posts are more retentive than passive posts, but they bring in more stress into the root dentin.65, 66
For many years, traditional custom cast posts were used which were extremely rigid, promote stress concentration in isolated points which increases the risk of root fracture and highly unesthetic.37
In 1990, Duret et al introduced fiber post with modulus of elasticity approaching that of the root dentin that effectively transmit and distribute the stress uniformly throughout the dentinal walls.16
These fibre posts can be adhesively luted to the root canal dentine using polymerizable resin cements. The inherent chemical homogeneity between the fibre post and the resin cement enables them to function together as a homogenous biomechanical unit, known as tertiary monoblock that mechanically replaces the lost dentin.52
Bonding strategies are usually employed to achieve micromechanical retention between the resin cement and root dentin.18
An important aspect of adhesive procedure for fibre post cementation is that two interfaces are involved namely, resin cement/root dentin interface and resin cement/fibre post interface. The adhesion in both interfaces is crucial for the long term success of post endodontic restoration.60
With regard to dentin and resin cement interface wide range of investigation was done using surface treatment of root canal dentin to remove
3
smear layer and increase surface energy followed by cementation with conventional and self-adhesive cements. In order to improve the adhesion between fibre post and resin cement interface, pre-treatment of the fibre post surface had been proposed.9
Glass fibre posts are composed of various types of glass fibres such as SiO2, CaO, B2O3, Al2O3, with inorganic fillers and a polymer matrix, commonly an epoxy resin or other resin polymers.68
Different surface treatments have been applied for conditioning of the post surface namely silanization, hydrofluoric acid etching, hydrogen peroxide, airborne-particle abrasion, methylene chloride, and laser irradiation.51
In recent times PEEK had evolved as a material of choice in various medical and dental applications. PEEK is a linear polyaromatic and semi- crystalline thermoplastic polymer with a suitable combination of high strength, stiffness, fatigue, and wear resistance. In addition, it is easy to process, non- toxic while possessing natural radiolucency as well as excellent thermal and chemical stability.58
PEEK based implants were used in (1).In the form of maxilla, facial and cranial implants. (2) For spine surgery – spinal cages. (3) For orthopedic surgery: In bone and hip- replacement surgeries, fixation plates, screws. (4) In cardiac surgery as intracardiac pump; heart valves. In dental applications for tooth replacement – dental implants from CFR-PEEK, dental prosthesis, intra- radicular posts.49
4
It has a melting point around 335.80C. PEEK can be modified either by the addition of functionalized monomers (pre-polymerization) or post polymerization modifications by chemical processes such as sulphonation, amination and nitration. The major beneficial property is its lower Young’s elastic modulus (3–4GPa) being close to human bone, enamel, and dentin.47
To obtain better adhesion, PEEK surface requires treatment since it has low surface energy. Sand blasting is an efficient method for modifying surface morphology and to increase the surface area other methods are tribochemical silica coating and chemical attack.61
BioHPP (High Performance polymer) is a PEEK variant that has been specially optimized for dental field. It has been strengthened with special ceramic filler, and optimized mechanical properties have been created for dental technical and/or dental medical use. This ceramic filler has a grain size of 0.3 to 0.5µm. Due to this very small grain size, constant homogeneity can be produced. The Elastic modulus of BioHPP lies in the range of 4000Mpa, which is resemblance of human bone, makes it a more natural material. The aesthetic white shade supports its use in field of prosthetic and post and cores.
Its insolubility in water makes it a biocompatible material, which is ideal for patients with metal allergies.83
Other properties of modified PEEK include Flexural strength of 150 MPa, Water absorption – 6.5µg/mm3, water solubility- 0.3 µg/mm3, melting temperature – 340oC. This modified PEEK is used in prosthodontics as a fixed dental prosthesis in both posterior and anterior areas, as a removable dental
5
prosthesis in denture frame works and telescopic works, and as transitional abutments and healing abutments in implant dentistry.83
Extensive search on the use of PEEK material as a post in medline/pubmed/cochrane databases didn’t yield positive results. Therefore there was a need to explore the use of PEEK as a post material from a research point of view and then to identify its clinical feasibility.
Glass fiber reinforced composite resin post had been widely used clinically and therefore it was chosen for comparative evaluation of push-out bond strength against modified PEEK in the current study
Therefore, the aim of this in vitro study was to compare and evaluate the push-out bond strength of prefabricated glass fiber reinforced composite resin post and customized modified polyetheretherketone (PEEK) post and also to identify the mode of failure in both the materials.
The null hypothesis for this study was that there would be no significant differences in the push-out bond strength between customized modified polyetheretherketone (PEEK) post and prefabricated glass fiber reinforced composite resin post.
The objectives of the present study were as follows:
1. To evaluate the basic and mean push out bond strength of prefabricated glass fiber reinforced composite resin post in coronal, middle and apical regions.
6
2. To evaluate the basic and mean push out bond strength of customized modified polyetheretherketone (PEEK) post in coronal, middle and apical regions.
3. To compare and evaluate the push out bond strength between sectioned (coronal) samples of prefabricated glass fiber reinforced composite resin post and its corresponding customized modified polyetheretherketone (PEEK) post.
4. To compare and evaluate the push out bond strength between sectioned (middle) samples of prefabricated glass fiber reinforced composite resin post and its corresponding customized modified polyetheretherketone (PEEK) post.
5. To compare and evaluate the push out bond strength between sectioned (apical) samples of prefabricated glass fiber reinforced composite resin post and its corresponding customized modified polyetheretherketone (PEEK) post.
6. To compare and evaluate the mode of failures for prefabricated glass fiber reinforced composite resin post and customized modified polyetheretherketone (PEEK) post following application of debonding force.
Review of Literature
7
REVIEW OF LITERATURE
Pashley et al DH (1995)51 proposed a theoretical modelling of dentine bonding in which he emphasized that the total bond strength was the sum of the strength of resin tags, hybrid layer and surface adhesion. Each of these three variables has a range of values that can influence its relative contribution to bonding and such theoretical modelling of dentine bonding can identify the relative importance of variables involved in the substrate, resins and surface adhesion.
Laurens P, et al (1998)35 studied the enhancement of adhesive bonding properties of PEEK with excimer laser treatment. The surface modifications induced by the treatment were characterized depending on the experimental parameters: treatments were realized at different fluences (both below and above the ablation threshold fluence), varying the number of pulses and the nature of the surrounding gas. Surface characterizations were performed using SEM (surface morphology), XPS (chemical analysis), and surface wettability (surface energy).
Finally, the bonding properties of the treated samples were investigated using epoxy adhesives. Concerning the bonding properties of the treated materials, influence of the surrounding gas on the efficiency of the laser treatment was investigated. It was concluded that surface modification, greatly influenced the adhesive properties of PEEK.
8
Cohen BI et al (1998)10 compared retentive values of three posts (Flexi- Post, Access Post, and ParaPost) cemented with five cements (Flexi-Flow, zinc phosphate, Advance, Duet, and Ketac-Cem) plus a control group that consisted of a Flexi-Post No. 2 dowel without cement. The results showed that Flexi-Post dowel was the most retentive post studied with values ranging from 303.91 pounds with Flexi-Flow Natural cements to 150.93 pounds without cement. They concluded that Flexi-Flow cements had a higher overall mean retention than other cements studied.
Asmussen E et al (1999)4 determined the stiffness, elastic limit and strength of a selection of endodontic posts. The posts tested in the study are zirconia post (Biopost, Cerapost), titanium post (PCR) and carbon fibre post (Composipost). The results showed that ceramic posts were very stiff and strong, with no plastic behaviour. The PCR post was as strong as, but less stiff than, the ceramic posts. Composipost had the lowest values for stiffness, elastic limit and strength of the post investigated.
Ferrari M et al (2000)18 evaluated the dentin morphology in root canals in terms of tubule orientation, density and increase in surface area after etching.
The samples of Group 1 were used to study tubular morphology in SEM. Groups 2 and 3 samples were etched with 32% phosphoric acid. The teeth in Group 2 were examined by SEM without further treatment. The observations revealed
9
variability in tubule density and orientation within different areas of any one sample. Therefore, they found that the increase in dentin surface area might be responsible for the enhanced bond strength after acid etching, but not all areas exhibited equal responses to etching.
Akkayan B et al (2002)2 compared the effect of 1 titanium and 3 esthetic post systems on the fracture resistance and fracture patterns of crowned, endodontically treated teeth. Teeth were restored with titanium, quartz fiber, glass fiber, and zirconia posts and numbered as groups 1, 2, 3, and 4, respectively. All posts were cemented with Single Bond dental adhesive system and dual polymerizing RelyX ARC adhesive resin cement. They found significant higher failure loads for root canal treated teeth restored with quartz fiber posts.
Behr et al (2004)7 compared the marginal adaptation of new self-adhesive Universal resin cement with only one application step, to the marginal adaptation of established cements and their corresponding adhesive systems. The study concluded that self-adhesive universal resin cement without pre-treatment can provide a marginal adaptation at dentin which is comparable to established luting agents.
De Munk J et al (2004)14 studied the bonding performance of a new auto adhesive cement (RelyXUnicem, 3M ESPE) to enamel and dentin, using a standard micro-tensile bond strength test set-up, and evaluated the interaction of this material with dentin by means of high-resolution electron microscopy. The
10
μTBS of RelyX Unicem to enamel was significantly lower than that of the control cement, whereas no significant difference was found when both cements were bonded to detain. Acid etching prior to the application of RelyX Unicem raised the enamel μTBS to the same level as that of the control, but was detrimental for the dentin bonding effectiveness.
Sahafi A et al (2004)63 evaluated the effect of various surface treatments Of prefabricated posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White) and zirconia (Cerapost) on the bonding of two resin cements: ParaPost Cement and Panavia F by a diametral tensile strength (DTS) test. The posts received surface treatments in three categories: 1) roughening by sandblasting and hydrofluoric acid etching; 2) application of primer by coating with Alloy Primer, Metal primer II and Silane and 3) a combination treatment in the form of roughening (sandblasting or etching) supplemented by the application of a primer or in the form of the Cojet system. The DTS of specimens was determined in a Universal Testing Machine. They concluded that the bonding of resin cement to titanium alloy posts was increased by several surface treatments of the post.
However, coating with primers as sole treatment had no effect on bonding. With the DTS method applied, none of the surface treatments had an effect on the bonding to glass fiber posts.
Balbosh A et al (2006)5 evaluated the effect of surface treatment on the retention of glass-fiber endodontic posts luted with resin cement and subjected to
11
artificial aging. Samples were then divided into 4 groups with 8 samples in each group. Post spaces were prepared to a depth of 10 mm. The tapered posts received 1 of 4 surface treatments: cleaning with alcohol (Alc), cleaning with alcohol and conditioning with ED-Primer material (Alc-ED), airborne-particle abrasion (Air), or airborne-particle abrasion and conditioning with ED-Primer material (Air-ED).
All posts were luted with a composite resin luting agent (Panavia F) after conditioning the canal dentin with auto-polymerizing dentin primer (ED-Primer) and without acid etching of the canal dentin. The results showed that treating the surface of the posts with ED-Primer material before cementation with Panavia F cement produced no significant improvement in the retention of the posts.
Airborne-particle abrasion of the surface of the post significantly improved the retention.
Bitter K et al (2006)8 evaluated the bond strengths of six different luting Cements to fiber-reinforced composite (FRC) posts after various pre-treatment procedures. Group 1: untreated control; Group 2: silane treatment; Group 3: CoJet treatment. The posts of each group were fixed with six different luting cements.
From the results they observed bond strengths (MPa) of the different resin the pre-treatment chosen, cements to the posts were significantly affected by the type of cement, but not by of the pre-treatment procedures . Without consideration Clearfil showed the highest bond strengths, followed by Panavia F and RelyX,
12
whereas Multilink, Variolink and PermaFlo showed significantly lower bond strength values.
Gerth HU et al (2006)21 analysed the chemical and physical properties of the dual curing self-adhesive resin cement Rely X Unicem with regard to their elemental composition, surface morphology and polymerization reaction. The intense chemical interaction with hydroxyapatite forming a polymer after setting seems to be relevant explanation to the improved clinical aspects and mechanical product properties.
Monticelli F et al (2006)41 verified the influence of different etching procedures of the post-surface on micro-tensile bond strength values between fiber posts and composite core materials. Chemical surface treatments including etching with potassium permanganate; treatment with 10% hydrogen peroxide;
treatment with 21% sodium ethoxide; etching with potassium permanganate and 10 vol. % HCl; silanization (control group) were performed on the post's surface.
The results achieved with potassium permanganate had a significant influence on microtensile interfacial bond strength values with both the tested materials.
Valandro LF et al (2006)77 tested the bond strength between a quartz fiber- reinforced composite post (FRC) and resin cement by using a chairside tribochemical silica-coating system for post surface conditioning.G1) Conditioning with 32% phosphoric acid (1 min), applying a silane coupling agent;
G2) etching with 10% hydrofluoric acid (1 min), silane application; G3) chairside
13
tribochemical silica coating method (CoJet System): air abrasion with 30-microm SiO2-modified Al2O3 particles, silane application. They concluded that the chair side tribochemical system yielded the highest bond strength between resin cement and quartz-fiber post.
Vano M et al (2006)78 evaluated the influence of various surface treatments to fiber posts on the microtensile bond strength with different composite resins. Group 1: immersion in 24% H(2)O(2) for 10 min and silanization for 60 s; group 2: immersion in 10% H(2)O(2) for 20 min and silanization for 60 s; group 3: immersion in 4% hydrofluoric acid gel for 60 s and silanization for 60 s; group 4: silanization of the post surface for 60 s and application of the bonding agent G-Bond; group 5: silanization of the post surface for 60 s (control group). The results showed that hydrogen peroxide and hydrofluoric acid both modified the surface morphology of fibre posts and with silane, significantly enhanced the interfacial strength between them and core materials.
D’Arcangelo C et al (2007)12 evaluated the effect of three post-surface treatments on flexural properties of fiber posts. Silanization, hydrofluoric etching, and sandblasting with 50 micron Al(2)O(3) were performed on post surfaces for each of the other groups. Flexural strengths and flexural modules were calculated and recorded. None of the surface pretreatments had a significant influence on the tested properties of the posts (p > 0.05). Visual analysis of SEM micrographs
14
showed significant changes of post surfaces determined by each conditioning treatment, which could increase post-retentive properties.
Hikita K et al (2007)30 evaluated the bonding effectiveness of five adhesive luting agents to enamel and dentin using a micro-tensile bond strength protocol. Following a correct application procedure, the etch-and-rinse, self-etch and self-adhesive luting agents are equally effective in bonding to enamel and dentin. The factors that negatively influenced the bond strength were bonding RelyX Unicem to enamel without prior phosphoric acid etching: no spate light curing of a light-polymerizing adhesive converted into a dual-polymerizing adhesive, and use of a dual cure luting agent with a low auto-polymerizable potential.
Radovic I et al (2007)59 evaluated the influence of different surface treatments on the microtensile bond strength of a dual-cured resin composite to fiber posts. Thirty-two glass methacrylate-based fiber posts (GC Corp.) were divided into two groups, according to the surface pretreatment performed. Group 1: sandblasting (Rocatec-Pre, 3M ESPE) and Group 2: no pretreatment. In each of the two groups posts received three types of additional "chair-side" treatments. (1) Silane application (Monobond S, IvoclarVivadent); (2) adhesive application (Unifil Core self-etching bond, GC); (3) no treatment was performed. The results
15
of the study suggested that sandblasting may give an increase in microtensile strength to methacrylate-based glass fiber posts, eliminating the need for additional "chair-side" treatments.
Monticelli F et al (2008)43 summarized the research on fiber posts and provide information regarding their bonding to resinous cement or composites, based on the results of original scientific full-papers from peer-reviewed journals listed in Pub Med. The search was conducted evaluating the different materials available for luting fiber posts to radicular dentin. Their results have been summarized in the following categories: conventional resinous cements and self- adhesive cements. According to the in vitro results, surface conditioning improves fiber post bonding properties and bond strength of pre-treated fiber posts to restorative materials is satisfactory.
Albashaireh ZS et al (2010)3 evaluated the influence of post surface conditioning methods and artificial aging on the retention and micro leakage of adhesively luted glass fiber-reinforced composite resin posts. The posts were submitted to 3 different surface treatments (n=24), including no treatment, etching with phosphoric acid, and airborne particle abrasion. Subgroups of the posts (n=8) were then allocated for 3 different experimental conditions: no artificial aging, no bonding agent; no artificial aging, bonding agent; or artificial aging, bonding agent. The results revealed retention values of the airborne-particle abrasion group were significantly higher than those of the acidic-treatment and no-
16
treatment groups. The application of bonding agent on the post surface produced no significant influence on retention and microscopic evaluation demonstrated that the failure mode was primarily mixed.
Choi Y et al (2010)9 evaluated the influence of different post surface treatments on the bond strength of a luting agent to a fiber post. Sixty-eight fiber reinforced posts (D. T. Light-Post) were divided into 4 groups and treated with 1 of the following surface treatment procedures: no treatment (NS) (control), silanization (SA) (Monobond-S), airborne-particle abrasion (AB) (Airsonic Alu- Oxyd), or silanization subsequent to airborne-particle abrasion (AB plus SA).
Specimens were bonded with dual-polymerizing resin-based luting material (Variolink II).The statistical results showed that airborne-particle abrasion provided a significant increase in bond strength between the post and the luting agent evaluated, without additional treatments.
Mumcu E et al (2010)45 compared by means of a micro push-out test the bond strengths of two types of fiber-reinforced posts cemented with the self-etch and self-adhesive luting cements and concluded that for all luting cements, their mean push-out bond strength values at the cervical region were higher than those at the medium and apical regions. In each root region, the self-etch and self- adhesive luting cements demonstrated similar push-out bond strength for each post type.
17
Prithviraj DR et al (2010)57 analyzed of the effect of surface treatment with ethyl alcohol, resin primer and air-borne alumina particle abrasion on retention of glass fiber posts, carbon fiber posts and cast metal posts cemented with dual cure resin cement. The statistical results revealed that there was significant difference in the retentive strength between air borne alumina particle abrasion and resin primer treated posts. Further, there was no significant difference between ethyl alcohol and resin primer treated posts.
Erdemir U (2011)17 evaluated the push-out bond strengths of a glass fiber post adhesively luted with self-etching resin based and self-adhesive luting cements, as well as modified application procedure of self-adhesive luting cements in combination with single step self-etch adhesives. Glass fiber posts (RelyX Fiber Post) were cemented with the following materials: group 1: ED Primer II/Panavia F 2.0 (PAN); group 2: RelyXUnicem (RU); group 3: Maxcem (MC); group 4: Adper Prompt L-Pop (PLP)/RelyXUnicem; group 5:
Optibondallin- one (OB)/Maxcem. The push-out bond strength values of modified application procedure of self-adhesive luting cements (RU and MC) in combination with single step self-etch dentin adhesives (PLP and OB) did not improve the push out bond strength of fiber post when compared with those where the conventional use of self-adhesive cements.
Mazzitelli (2011)39 assessed the push-out bond strength of self-adhesive resin cements bonded to epoxy-resin based fiber posts and concluded that RelyX
18
Unicem attained the higher push-out bond strength values among the tested cements. The use of an elongation tip is highly recommended for placing the material inside the root canal in order to limit the formation of defects at the adhesive interfaces.
Hallmann L, et al (2012)27 investigated on improvement of adhesive properties through different surface pretreatments. PEEK blanks were cut into discs. All disc specimens were polished with 800 grit SiC paper and divided into 6 main groups. Main groups were divided into 2 subgroups. The main groups of 32 specimens each were treated as follow: (1) control specimens (no treatment), (2) piranha solution etching, (3) abraded with 50 µm alumina particles and chemical etching, (4) abraded with 110 µm alumina particles and chemical etching, (5) abraded with 30 µm silica-coated alumina particles and chemical etching, (6) abraded with 110 µm silica-coated alumina particles and chemical etching. Plexiglas tubes filled with a composite resin (RelyX Unicem) were bonded to the specimens. The adhesives used were Heliobond and Clearfil Ceramic Primer. Each specimen was stored in distilled water (37 ◦C) for 3 days.
Tensile bond strength was measured in a universal testing machine and failure methods were evaluated. It was evaluated that Airborne particle abrasion in combination with piranha solution etching improves the adhesive properties of PEEK. Proper choice of adhesive system also plays a major role in better bonding.
19
Kahnamouei MA et al (2012)31 investigated the push-out bond strengths of quartz fibre posts to root dentin with the use of different total-etch and self- adhesive resin cements and concluded that cementation of quartz fibre posts with self-adhesive cements provides higher push-out bond strengths, especially in the apical region, while, total-etch cements result in more uniform bond strengths in different regions of the root canal.
Zicari F et al (2012)80 evaluated the effect of the length of fibre-posts and type of adhesive cement on the fracture resistance of endodontically treated teeth, after fatigue loading and concluded that endodontically treated teeth restored with short posts may survive fatigue loading as well as long posts, although a congruency between post and prepared root canal is advisable for improved retention. Using short posts rather than long posts may yield higher fracture resistance and also lead to favorable failures, the self-adhesive or self-etch adhesive strategies do perform equally well, with regard to fatigue loading and fracture resistance.
Zicari F et al (2012)81 evaluated the effect of different factors on the push-out bond strength of glass fiber posts luted in simulated root canals using different composite cements. All three variables, namely the type of post, the composite cement and the post surfaces pre-treatment, were found to significantly higher push-out bond strength. They concluded that the push-out bond strength was found to significantly reduce with depth from coronal to apical.
20
Gencoglu N et al (2013)20 evaluated the effect of different surface treatments on the bond strength of fiber post with luting agent to root canal dentin.75 fiber-posts (Rebilda, Voco) were divided into 5 groups and treated with one of the following surface treatment procedures: no treatment (control), silanization, etching by % 9.6 hydrofluoric acid, sand blasting with 50 milimicron Al2O3 and bonded (15 of each).The study showed that bonding group had highest bond strength in coronal section, and sandblasted group in middle and apical section (p<0.05). The different surface treatment affected the bond strenght of fiber post to root canal dentin.
Hahnel S, et al (2014)26 evaluated the effect of biofilm formation on modern implant materials such as titanium, zirconia and PEEK. Specimens were prepared from the implant abutment materials titanium, zirconia, and polyetheretherketone (PEEK); specimens made from polymethylmethacrylate (PMMA) were used for reference. All specimens were polished to high gloss using silicon carbide paper; surface roughness was determined using profilometry, and surface free energy was calculated from contact angle measurements. After the simulation of salivary pellicle formation, multispecies biofilm formation was initiated by exposing the specimens to a suspension of Streptococcus gordonii, Streptococcus mutans, Actinomyces naeslundii, and Candida albicans for either 20 or 44 h. viable microbial biomass adherent to the specimens and the percentage of dead microorganisms in the different biofilms were determined. It was
21
concluded that biofilm formation on PEEK material is equal/ less when compared to titanium and zirconia.
Ma, Rui et al (2014)38 evaluated the bioactivity of PEEK. A nanocalcium silicate (n-CS)/ polyetheretherketone (PEEK) bioactive composite was prepared using a process of compounding and injection-molding. The mechanical properties, hydrophilicity, and in vitro bioactivity of the composite, as well as the cellular responses of MC3T3-E1 cells (attachment, proliferation, spreading, and differentiation) to the composite, were investigated. The results showed that addition of nanocalcium silicate improved its mechanical properties, hydrophilicity, cell viability and biocompatibility.
Sipahi C et al (2014)68evaluated surface roughness and bond strength of glass fiber posts to resin cement after various surface treatments. The posts were randomly assigned to six groups of pre-treatment (n = 10/group): Group C, untreated (control); Group SB, sandblasted; Group SC, silica coated; Group HF, hydrofluoric acid-etched; Group N, Nd:YAG laser irradiated; Group E, Er:YAG laser irradiated. Surface roughness of the posts was measured before and after pre-treatment. The posts were then bonded to resin cement and tensile bond strengths were determined in a universal testing machine. The findings of the study they concluded that hydrofluoric acid-etching, silica coating and Er:YAG
22
laser irradiation provided a significant increase in bond strength between glass fiber posts and resin cement.
Druck CC et al (2015)15 evaluated the effect of fiber post surface treatments on push-out bond strength between fiber post and root dentin. Six groups (n=10): Gr1- Silane coupling agent (Sil)+Conventional resin cement AllCem (Al C); Gr2- Sil+Conventional resin cement RelyX ARC (ARC); Gr3- tribochemical silica coating (TBS)+AlC; Gr4 TBS+ARC; Gr5- No treatment (NT)+AlC; Gr6- NT+ ARC. The study concluded that the fiber post surface treatment appears have no Influence on bond strength between fiber post and root dentin.
Hattar S et al (2015)28 evaluated the strength of the bond between newly introduced self-adhesive resin cements and tooth structures. Three self-adhesive cements (SmartCem2, RelyXUnicem, seT SDI) were tested. The resulted SBS values ranged from 3.76 to 6.81 MPa for cements bonded to enamel and from 4.48 to 5.94 MPa for cements bonded to dentin (p > 0.05 between surfaces). There were no statistically significant differences between the SBS values to enamel versus dentin for any given cement type. All cements exhibited adhesive failure at the resin/tooth interface.
Younes et al (2015)79 evaluated the effect of various fiber reinforced composite (FRC) post surface treatments on its tensile bond strength to root canal dentin.Group1:- surface treatment with 4plasma (argon plasma), Group2:- surface
23
treatment with air born- particle abrasion, Group3:- surface treatment with air born-particle abrasion and silane, Group4:- control group without any surface treatment. Self-adhesive cement was used for cementation of all posts. The statistical result showed that the tensile bond strength of the luting agent to the post was significantly affected by surface treatment (P < 0.05). From the results they concluded that both plasma surface treatment and air-born particle abrasion with silane application improved the bonding of fiber post to the resin cement.
Daneshkazemi A et al (2016)13 to evaluated the effect on the bond strength to composite resin of pretreating glass fiber post surfaces with hydrogen peroxide, phosphoric acid, and a silane coupling agent. Glass fiber posts were treated for 1 or 5 minutes with 30% hydrogen peroxide or 35% phosphoric acid.
Treated posts were divided into silanization and no silanization groups. Control groups included no treatment or treatment with silanization alone (total of 10 groups; n=14).They concluded that silane coupling agent had a significant effect on the bond strength of the tested glass fiber posts to composite resin, whereas 30% hydrogen peroxide or 35% phosphoric acid did not.
Rocha, et al (2016)61 studied about the bonding properties of Polyetheretherketone (PEEK) with human dentin and its surface treatments. One hundred PEEK cylinders (3 mm×3 mm) were divided into five groups according to surface treatment: silica coating, sandblasting with 45 μm Al2O3 particles, etching with 98% sulfuric acid for 5, 30 and for 60 s. These cylinders were luted
24
with resin cement onto 50 human molars. First, each tooth was embedded in epoxy resin and the buccal dentin surface was exposed. Then, two delimited dentin areas (∅:3 mm) per tooth were etched with 35% phosphoric acid and bonded with a two-step self-priming adhesive system. After the luting procedure the specimens were stored in water (24 h/37 °C). Shear bond strength (SBS) was tested using a universal testing machine and failure types were assessed. It was concluded that both physical and chemical surface treatments produced adhesion between PEEK, resin cement and dentin and Adhesive and mixed failures were predominant modes of failures occurred.
Starwarczyk B, et al (2016)70 compared the PEEK as core material with other gold standard core material. Standardized specimens (10 mm × 10 mm × 1.5 mm) reflecting four core (polyetheretherketone (PEEK), zirconia (ZrO2), cobalt–
chromium–molybdenum alloy (CoCrMo), and titanium oxide (TiO2) and veneering materials (VITA Mark II, IPS e.max CAD, LAVA Ultimate and VITA Enamic, all in shade A3; thickness: 0.5, 1.0, 1.5 and 2 mm, respectively) were fabricated. Specimens were superimposed to assemblies, and the color was determined with a spectrophotometer. It was concluded that PEEK as core material showed comparable outcomes as compared to ZrO2 and CoCrMo, with respect to CieLab-System parameters for each veneering material.
25
Kirmali O et al (2017)33 compared the effect of different pretreatments (fiber post) with the laser-activated irrigation (LAI) technique (for removal of the smear layer) on root canal dentin in terms of push-out bond strength (PBS) in a fiber post. 50 quartz fiber posts were randomly assigned to 5 groups (n = 10) according to the surface treatments as follows: group S (sandblasting), group N1 and group N2 (neodymium: yttrium-aluminum-garnet laser irradiation [2 W, 200 mJ, 10 Hz, with pulse durations of 180 or 320 microseconds), group HF (9.7%
hydrofluoric acid etched), and group C (control with no treatment). The LAI technique when used with 17% EDTA had a significant effect on the amount of smear layer removed from the root canal dentin, which was also detected in the fracture pattern (adhesive failure [resin-post interface]).
Prado M et al (2017)56 evaluated the effect of different surface treatments on fiber post cemented with a self-adhesive system. Sixty fiber glass epoxy resin posts were cleaned, dried and divided into 6 groups. Control (no surface treatment), silane (silane coupling agent was applied homogeneously on surface), 24% hydrogen peroxide (H2O2) (immersion during 1min), blasting (blasting with aluminum oxide for 30s), NH3plasma (plasma treatment for 3min) and HMDSO plasma (plasma treatment for 15min). After the treatments, posts were inserted into a silicon matrix that was filled with the resin cement RelyX U200. They concluded that surface treatments influenced adhesion of fiber glass post luted with the self-adhesive cement RelyX U200. Silane, blasting with aluminum oxide
26
and plasmas (NH3 and HMDSO) showed results superior to 24% hydrogen peroxide.
Tuncdemir AR et al (2018)73 evaluated of different surface treatments on fiber post cemented with self curing adhesive system. Thirty glass fiber posts were divided into 3 groups (n=10). Control group (without any surface treatment), airborne abrasion group (50µm aluminum-oxide), and femtosecond laser (FS) group. After the surface treatment posts were luted in root canals with selfcureing adhesive cement (Multilink Automix, Ivoclar, Vivadent). Aluminum-oxide air- borne particle abrasion group showed higher bond strength than FS irradiation group.
Lambriaga, et al (2018)34 assessed the effect of non-thermal plasma on the shear bond strength of resin cements to polyetherketoneketone (PEKK), material in the family of polyetheretherketone (PEEK) in comparison to other surface treatment methods. Eighty PEKK discs were subjected to different surface treatments: (1) Untreated (UT); (2) Non-thermal plasma (NTP); (3) Sandblasting with 50 μm Al2O3 particles (SB); and (4) Sandblasting + Non-thermal plasma (SB+NTP). After each surface treatment, the contact angle was measured. Surface conditioning with VisioLink was applied in all groups after pre-treatment. RelyX Unicem resin cement was bonded onto the PEKK specimens. After fabrication of the specimens, half of each group (n=10) was initially tested, while the other half was subjected to thermocycling (5°C to 55°C at 10,000 cycles). Shear bond
27
strength (SBS) testing was performed using a universal testing machine, and failure modes were assessed using stereomicroscopy. It was noted that the shear bond strength between PEKK and resin cements was improved using non-thermal plasma treatment in combination with sandblasting than other pretreatment methods.
Materials and Methods
28
MATERIALS AND METHODS
The present in vitro study was conducted to comparatively evaluate the push out bond strengths between prefabricated glass fiber reinforced composite resin post and customized modified polyetheretherketone (PEEK) post.
The following materials, equipment and methodology were employed:
Materials and Instruments used for the study:
30 extracted single rooted human mandibular first premolars (Fig. 1)
High speed Airotor handpiece (NSK, Dental Mfg.Co.Ltd, Japan) (Fig. 2)
Safe side Diamond discs (Mani Inc, Japan) for decoronation. (Fig. 3)
Addition silicone impression material (Aquasil – putty index, Dentsply Sirona, Germany)( Fig. 4a)
Tooth coloured self cure acrylic resin powder and liquid monomer (Dental products of India, LTD, India) ( Fig. 4b)
Arckansas stone (Bullet TM, India) ( Fig. 4c)
5 ml disposable Syringe (Hindustan syringes & Medical Services, India) (Fig. 4d)
X mart Endomotor (Dentsply, Japan) (Fig. 5a)
Stainless steel Kerr files (length 21mm: 10-50, Mani Inc, Japan) (Fig. 5b)
Rotary Files (Diadent, Korea ) (Fig. 5c)
17% EDTA (Ammdent Dental Products, India) (Fig. 5d)
29
RC-Seal root canal sealer (Prime dental, Thane, India ) (Fig. 5e)
3% Sodium hypochlorite (Prime Dental Products PVT, India) (Fig. 5f)
Saline 0.9% (Paradental drugs, India) (Fig. 5g)
2.5 ml disposable Syringe (Hindustan syringes & Medical Services, India) (Fig. 5h)
Gutta percha (6%, DiaDent, Korea) (Fig. 5i)
Distilled water (EMPLURA®, Mumbai) (Fig. 6)
Micromotor hand piece and unit (Marathon-3,Saeyang microtech, Korea) (Fig. 7a)
Peeso reamers (size 1-6; Mani Inc, Japan) (Fig. 7b)
REFORPOST-post space drill (Angelus,Brazil) (Fig. 7c)
Glass fiber reinforced composite resin post-1.5mm Diameter (REFORPOST- Size #3,Angelus,Brazil) (Fig. 8)
Dental Inlaycasting Wax (GC Corporation, Tokyo, Japan) (Fig. 9a)
Wooden tooth picks (Krop brand, India) (Fig. 9b)
Isolating Liquid (Yeti Lube , Yetti Dental ,Germany) (Fig. 9c)
P.K.T instruments (Dispodent, Chennai, India ) (Fig. 9d)
Spruing Wax (Sigmadent, Mumbai, India) (Fig. 10)
Deguvest powder and liquid investment material (Degudent GmbH , Germany ) (Fig. 11)
BioHPP Peek Granlues (BioHPP ds2 , Bredent , Germany) (Fig. 12)
30
Customized Peek post ( BioHPP, Bredent, Germany) (Fig. 13)
Aluminium oxide powder 50μm (Alminox 50µm ,Delta labs, India) (Fig. 14)
Silane coupling agent (Silano, Angelus, Brazil) (Fig. 15a)
Applicator tips (Denmax, India) (Fig. 15b)
Maxcem elite dual-cure resin cement (Kerr, New south wales, Australia) ) (Fig. 16a)
Intra canal tips (Delta,India) ) (Fig. 16b)
31 S
No
Material name
Manufacture name
Chemical composition Commercial Name
Lot Number 1 Glass fiber
reinforced composite resin post
ANGELUS Glass
fiber(80%),pigmented resin(19%),stainless steel
filament(1%)
Reforpost 42430
2 PEEK post (BioHPP)
BREDENT BioHPP ds 2 granules BioHPP granules
458616
3 Silane
coupling agent
ANGELUS Silane and ethanol Silano 44626
4 Alumina
particles
DELTA Al2O3 particles - 50µm size Alminox 10104 5 Dual cure
resin cement
KERR 1,6-hexanediyl
bismethacrylate ( 5-10%) 2-hydroxy-1,3-
propanediyl bismethacrylate-(5-10%) 7,7,9(or 7,9,9)-trimethyl-
4,
13-dioxo-3,14-dioxa-5, 12-diazahexadecane-1, 16-diyl bismethacrylate-
(1-5%)
3-trimethoxysilylpropyl Methacrylate-(1-5%) 1,1,3,3-tetramethylbutyl Hydroperoxide-(0.1-1%)
Maxcem Elite 6785838
32 EQUIPMENTS:
PEEK Burnout Furnace (VULCAN 3-130,Dentsply, JAPAN) (Fig. 17)
PEEK Vacuum press device(2 press system, Bredent, GERMANY ) (Fig.
18)
Sand blaster – Ideal blaster (Delta, Chennai, INDIA) (Fig. 19)
Light curing unit (3M ESPE, GERMANY) (Fig. 20)
Hard tissue microtome (LEICA SP 1600, Leica Microsystems Nussloch GmbH, Germany) (Fig. 21)
Universal testing machine (Instron 3369, Massachusett, USA) (Fig. 22)
Optical microscope (OIAL/MET/01-A Dewinter Technologies, Maharastra, INDIA) (Fig. 23)
DESCRIPTION OF THE EQUIPMENT USED:
PEEK BURN OUT FURNACE (Fig. 17):
Burn out furnace (VULCAN 3-130) was employed in the present study to carry out the burn out process in fabrication of customized PEEK post. It has a high performance and longer life and more durable than other furnaces. It consists of wide operating temperature range (50oc – 1100oc) along with smooth, low force vertical lift door, with roll back action; it gives maximum access with minimum vertical space. It has a programmable controller with 9 three stage
33
programs (6 segments each) and 1 program with single temperature hold. It is easy to operate and program with user friendly graphic interface.
It is also used for wax burnout, material ashing, ceramic firing, glass seal firing, material heat treating.
BIOHPP VACUUM PRESS (Fig. 18):
BioHPP vacuum press (for 2 press, BREDENT) was employed in this study for fabrication of customized PEEK post. The initial situation is a wax model, which is invested in a mould with an investment material especially developed for this purpose. This mould is heated to between 630oc and 850oc in a pre-heating oven, the wax is melted away and then cooled at 400oc. At this temperature, BioHPP is brought to the melting range of this investment material mould and melted down. The insertion of the press pinger and transfer of the mould into the for 2 press system then takes place. By raising the lift, the pressing procedure is trigged automatically and takes place the vacuum. After completion of the vacuum, the mould is cooled down to the room temperature within 35 minutes- whilst maintain the pressing pressure, and then be devasted as usual.
The entire injection process is completed fully automatically. A blue LED light marks the end of the process.
34 SANDBLASTER (Fig. 19):
Sandblaster (Ideal blaster 1510) was employed in the present study to carry out the sandblasting of the prefabricated glass fiber reinforced composite post and customized modified (PEEK)post with 50µm Al203 particles.it was manufactured by Delta Labs, Chennai, India. Sandblaster is used for fine blasting procedures of crown & bridges. The unique booster technology offers a maintenance free operations and smooth flowing of the blasting medium. The chamber design allows clear visibility and easy cleaning. It was comprised of pressure gauge with regulator, wide view acrylic shield & has bright illumination about 2000 lux, quick and easy replacement of bulb, precise blasting due to the nozzle design. It has stainless steel foot control and a long lasting & wear resistance nozzle.
LIGHT CURING UNIT (Fig. 20):
Light curing unit (3MESPE, Germany) consist of high, regular, low curing modes with interchangeable light guides, multiple curing options with periodic level shifting. The unit comes with three working modes as full, ramping, pulse . LED light cures uses the principle of Ray Radiation solidify the light sensitive resin by shooting at it in a short time. Time setting ranges from 5s, 10s, 15s, 20s, 25s, 30s, 35s, unto 40s, It has power input of AC 100v-240v 50Hz/60Hz and light output of 850W/cm2 – 1000W/cm2.
35 HARD TISSUE MICROTOME (Fig. 21):
Hard tissue microtome (LIECA SP 1600) was employed in the present study to carry out the sectioning of the teeth samples which were embedded in the self-cure acrylic resin blocks. It is a Saw Microtome specifically for “cutting”
extremely hard and brittle materials such as bone, ceramics and reinforced plastics. To make a section, the object holder is guided extremely slowly against the saw rotating at a speed of approx. 600 rpm. The built-in water cooling device prevents overheating of the object and removes sawdust from the cutting edge.
The section thickness is set manually with a knurled screw on the object arm.
UNIVERSAL TESTING MACHINE (Fig. 22):
Universal testing machine (Instron 3369) was employed in the present study for obtaining push out bond strength value for the test samples. This machine rests on a table top. It consists of a lower chamber, upper chamber and a display board to display the amount of force needed and is connected to a computer. The upper member is attached to the lower with help of two horizontal bars, which also houses the hydraulic pressure machine attached to the upper member. The lower portion has a bench wise test specimen to hold the test specimens. The whole unit is attached to a computer for recording and converting OPTICAL MICROSCOPE (Fig. 23): (OIAL/MET/01-A), also called the light microscope, uses a combination of light and lenses to magnify an image. It is an Inverted metallurgical microscope with image analyzer, make from Dewinter
36
Technologies. Optical microscopes are used in the viewing of small objects such as cells. The major imaging principle of the optical microscope is that an objective lens with very short focal length is used to form a highly magnified real image of the object. The eyepiece lens (the one closest to your eye) magnifies the image from the objective lens, rather like a magnifying glass. On some microscopes, you can move the eyepiece up and down by turning a wheel.
This gives you fine control or "fine tuning" of the focused object. It has a magnification in range of 50X, 100X, 200X, 500X and 1000X.
Inclusion Criteria:
Extracted single rooted and single canal mandibular first premolar with mature apices.
Exclusion Criteria:
Teeth with dental caries, resorption, open apex, fractures or cracks, Dilacerations, double canals were excluded.
37 METHODOLOGY
The present in vitro study was conducted to comparatively evaluate the push out bond strengths between prefabricated glass fiber reinforced composite resin post and customized modified polyetheretherketone (PEEK) post.
The methodology adopted in the present study was described under the following Sections:
PREPARATION OF THE SAMPLES
I. Preparation of the extracted teeth samples II. Decoronation of the extracted teeth samples
III. Embedding procedure of the roots in the self-cure acrylic resin IV. Root canal treatment procedure
V. Post space preparation VI. Grouping of the test samples
VII. Prefabricated glass fiber post Surface treatments and cementation a. Surface treatments of the glass fiber post
b. Cementation of the glass fiber post
VIII. Fabrication of Customized modified PEEK post, Surface treatments and Cementation
a. Preparation of the wax pattern b. Spruing of the wax pattern c. Investment of the wax pattern
