RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,
KARNATAKA, BANGALORE
PROFORMA FOR THE REGISTRATION OF SUBJECT FOR DISSERTATION
1 / NAME OF THE CANDIDATE AND ADDRESS / DR. SHABINA AYSHA BEGUM MDEPARTMENT OF PROSTHODONTICS
BANGALORE INSTITUTE OF DENTAL SCIENCES
BANGALORE 560027
2 /
NAME OF INSTITUTION
/ BANGALORE INSTITUTE OF DENTAL SCIENCES AND HOSPITAL & POST GRADUATE RESEARCH CENTRE.3. / COURSE OF STUDY AND SUBJECT / MASTER OF DENTAL SURGERY (M D S)
PROSTHODONTICS AND CROWN & BRIDGE.
4 / DATE OF ADMISSION TO COURSE / 23/05/2012
5 / TITLE OF THE TOPIC / A SPECTROPHOTOMETRIC EVALUATION TO COMPARE THE OPTICAL INFLUENCE OF TWO DIFFERENT ALL-CERAMIC SYSTEMS WITH TWO DIFFERENT POSTS - AN IN-VITRO STUDY.
6. / BRIEF RESUME OF THE INTENDED WORK
6.1 Need for the Study:
Various methods of restoring pulpless teeth have been reported for more than 200 years. Innovations in material science and clinical techniques have expanded the number of treatment options available for non-vital anterior teeth. A lot of attention was focused on the mechanical properties of the post with respect to the tooth structure as against its esthetic properties. Carbon, titanium and cast metal posts are popularly in use today, however their color differs greatly from that of dentin. In this view, it has to be questioned how these posts can be masked by the cement, ceramic thickness, and shade of all-ceramic crowns. Several physical and clinical factors influence aesthetics of all-ceramic restorations such as color scale, light source during color evaluation, characteristic of core material, color of supporting tooth, presence of root post, and type of cement.
With this in mind, the purpose of this study is to investigate the influence of two different posts (1 opaque and 1 transparent) on the shade/esthetics of two different all ceramic systems. Spectrophotometric analysis will be used in this study to compare the reflection, scattering, translucency and absorption coefficient between that of natural teeth and ceramic restorations.
6.2 REVIEW OF LITERATURE
1. Gottfried Knispel et al (1991)1 concluded that resin-based restorative materials have to function properly and fulfill esthetic demands; restorations must harmonize in shape and shade with natural teeth. The human perception of color is affected by external factors. The influence of these factors is discussed in regard to two pairs of composite resins (Silux/Valux and PekaluxIPekafiU). With the knowledge of the influence of these factors and with the accuracy of modern color measurement instruments, it was then possible to carry out restorative work to meet the highest esthetic standards.
2. Alessandro Vichi et al (2000)2 conducted a study to evaluate the influence of different types of posts and cores on light transmission through all-ceramic crowns and concluded that the surface colored glass ceramic was the most translucent crown. At the standard crown thickness used, there were small, significant spectrophotometric differences, but not clinical differences among the combinations tested. These findings showed no esthetic contraindications for the use of polished gold alloy posts and cores with all-ceramic crowns.
3. Frank Butz et al (2001)3 in his study to compare the survival rate and fracture strength of endodontically treated maxillary incisors with moderate coronal defects restored with different post-core systems after exposure to an artificial mouth. Concluded that the prefabricated titanium posts with composite cores, zirconia posts with heat-pressed ceramic cores, and cast posts-cores yield comparable survival rates and fracture strengths for the restoration of crowned maxillary incisors with moderate coronal defects. Survival rates and fracture strengths for zirconia posts with composite cores are significantly lower, so this combination cannot be recommended for clinical use.
4. Stefano Carossa et al (2001)4 evaluated the influence of color of 2 commercially available non-metallic opaque posts (carbon fiber and zirconia) and an experimental esthetic post, and the shade and thickness of luting cements on the esthetics of all-ceramic factors and with the accuracy of modern color measurement instruments. The results of the study of the all-ceramic IPS-Empress glass-ceramic restoration were not affected by the presence of different substrates with different colors when the thickness was more than 2.0mm. When the ceramic thickness was less than 1.0 mm, the use of a full ceramic crown was contraindicated because color matching of the abutment was required to ensure an acceptable esthetic result.
5. Q Li et al (2009)5 evaluated the optical influence of core build-up composites on the resultant color of ceramic–composite combinations, and analyzed the color difference of ceramic–composite combinations to Vita Lumin shade guide with the same nominal shade. The study showed that the color of underlying core composite had a significant influence on the resultant color of an all-ceramic restoration.
6. Bong-Joom Kim et al (2009)6 conducted a study to measure the difference in color and color coordinates between the same shade-designated resin composites from different brands, and to determine the influence of shade designation on the difference in color and color coordinates between them. And concluded that the color difference between the same shade-designated resin composite from different brands varied by the shade designation and was perceptible in more than half of the compared pairs, optical properties of resin composites should be considered differently by the shade designation and brand when selecting these materials.
7. Kummagai.N et al (2012)7 conducted a study on the effect of transluceny of Y-TZP based all-ceramic crowns fabricated with different sub-structure thickness and extension. And conclude that the translucency of a Y-TZP based all-ceramic crowns may influence its esthetic outcome when it is used on a discolored abutment tooth. Clinicians should be aware of the effect of substructure design on the translucency of Y-TZP based all-ceramic crowns.
6.3 OBJECTIVES OF THE STUDY
The objectives of this in-vitro study is to analyze by a spectrophotometer and to comparatively assess the influence of 2 posts, 1 opaque (titanium) and 1 transparent (glass fiber) on the esthetics/ shade of all ceramic crowns of two different systems (zirconia and lithium disilicate) using the natural extracted tooth as reference.
7. / MATERIALS & METHODS
7.1 Material used:
1. 2.0 mm thickness samples of two different all ceramic systems (Zirconia ZrO2 - Z and Lithium disilicate SiO2LiO2 -L) of the same shade.
2. Two posts P1(Titanium- Filpost) and P2 (Glass fiber – PD Swies)
3. Resin bonded cement(Calibra) of a standard color and thickness (25µ)
4. Resin composite core build-up material (Multicore, Ivoclar) of standard shade
5. Extracted teeth (40 Nos)
6. Root canal files
7. Oburating material (GP points - Denstply)
8. Post Kits (Gates Glidden Drill - Mani and Peeso Reamer - Mani)
9. Impression material
7.2 Equipmentsused:
1. Air-rotor (NSK)
2. Micro motor (NSK)
3. Spectrophotometer (Analytik Jena – Model specord S600) to assess the reflection, scattering, translucency and absorption coefficient of the light through the objects
7.2 Method of Collection of Data:
METHODOLOGY
Forty anterior teeth (central incisors) extracted due to compromised periodontal conditions will be obtained. The teeth will then be subjected to spectrophotometric analysis to assess the translucence, absorption co-efficient and remittance of light. These values will form the basic reference for comparison with the two ceramic systems. The extracted teeth will then be stored in distilled water and will be prepared for intentional root canal therapy. Following this, the 40 teeth will be divided randomly into 4 groups of 10 teeth each - Groups A, B, C and D.
The types of material and the combination of post to be used in the various groups is as follows
1. Group A
· Zirconia ceramic crown of 2mm thickness (Z)
· Titanium post (P1)
· Composite core build up material
· Resin bonded luting cement
2. Group B
· Zirconia Ceramic crown of 2mm thickness (Z)
· Glass fiber post (P2)
· Composite core build up material
· Resin bonded luting cement
3. Group C
· Lithium disilicate ceramic crown of 2.0 mm thickness (L)
· Titanium Post (P1)
· Composite core build up material
· Resin bonded luting cement
4. Group D
· Lithium disilicate ceramic crown of 2.0 mm thickness (L)
· Glass fiber post (P2)
· Composite core build up material
· Resin bonded luting cement
Thus there will be 4 combinations to be compared with each other and the natural teeth, with 10 samples in each combination thereby making it a total of 40 samples.
The values obtained in the spectrophotometric analysis will be plotted on a graph along with the values of the wavelength provided and analyzed statistically by ANOVA test of variance.
7.3 Does the study require any investigation or intervention to be conducted on the patients or other animals? If so please describe briefly.
No
7.4 Has ethical clearance been obtained from your institution?
Not applicable
8. / LIST OF REFERENCES
1. G Knispel. Factors affecting the process of color matching restorative materials to natural teeth. Quint Int 1991:22:525-5.
2. A Vichi, M Ferrari, and CL Davidson. Influence of ceramic and cement thickness on the masking of various types of opaque posts. J Prosthet Dent 2000; 83:412-7.
3. F Butz, ÁM Lennon, G Heydecke, JR Strub. Survival Rate and Fracture Strength of Endodontically Treated Maxillary Incisors with Moderate Defects Restored with Different Post-and-Core Systems: An In Vitro Study. Int J Prosthodont 2001; 14:58–64.
4. S Carossa, S Lombardo, P Pera, M Corsalini, ML Rastello, G Preti. Influence of posts and cores on light transmission through Different all-ceramic crowns: Spectrophotometric and Clinical Evaluation. Int J Prosthodont 2001; 14:9–14.
5. Q. Li, H. Yu, Y.N. Wang. Spectrophotometric evaluation of the optical influence of core build-up composites on all-ceramic materials. Dent materials 2009;25; 158–165
6. BJ Kim, YK Lee. Influence of the shade designation on the color difference between the same shade-designated resin composites by the brand. Dent materials. 2009;25; 1148–1154
7. N Kummagai, H Hirayama, MD Finkelman, SN Ishikama. The effect of translucency of Y-TZP based all-ceramic crowns fabricated with different sub-structure designs. J dent. 2012; 10-005
9. / Signature of Candidate
10. / Remarks of the Guide
11. / 11.1 Guide
11.2 Signature / DR.KARUNAKAR SHETTY.
Professor
Bangalore Institute of Dental sciences and Hospital,
Bangalore
11.3 Co-Guide / DR. G.R RAHUL.
Professor & head
Department of Prosthodontics
Bangalore Institute of Dental Sciences and Hospital, Bangalore.
11.4 Signature
11.5 Head of the Department
11.6 Signature / DR. G.R RAHUL.
Professor & head
Department of Prosthodontics
Bangalore Institute of Dental Sciences and Hospital, Bangalore.
12. / 12.1 Remarks of the
Chairman and Principal
12.2 Signature
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