THE INFLUENCE OF COMPRESSIVE CYCLIC LOADING ON THE RETENTION OF CAST CROWN COPINGS CEMENTED TO IMPLANT ABUTMENTS

Transcription

1 THE INFLUENCE OF COMPRESSIVE CYCLIC LOADING ON THE RETENTION OF CAST CROWN COPINGS CEMENTED TO IMPLANT ABUTMENTS A thesis submitted in partial fulfillment for the Degree of Doctor of Clinical Dentistry (Prosthodontics) James Dudley BDS (Adel), GradDipHlthServMt (Mon), MHlthServMt (Mon) Dental School Faculty of Health Sciences The University of Adelaide September 2008

2 LAYOUT OF THIS THESIS This thesis is presented in two sections: Section 1: Thesis as detailed in Contents Section 2: Article submitted and accepted for publication in the Australian Dental Journal 2008; 53(4)

3 SECTION 1

4 CONTENTS Summary... i Acknowledgements. iii Abbreviations..... iv Chapter Introduction Aims of the study... 3 Chapter 2 Literature Review Dental implants History Implant types Abutment types Clinical use Cement versus screw-retained crowns Cement-retained crowns Screw-retained crowns Dental cements Cement film thickness Marginal leakage Cement failure Filling abutment screw access channels In vitro conditions Crown seating pressure Humidifier. 22

5 2.5.3 Thermocycling Development of in vitro tooth wear simulations Specific in vitro tooth wear conditions Findings from natural tooth / crown retention studies Findings from implant abutment / crown retention studies Ranking order studies Abutment design variation studies In vitro simulation studies Reusing abutments and crowns Conclusions 54 Chapter 3 Materials and Methods Components Component construction Crown coping construction Laboratory analog / implant abutment / housing base construction Specimen testing Cementation In vitro experimental conditions Testing protocol Cleaning protocol Testing schedule Repeated procedure Calculation of abutment surface area Statistical analysis Pilot study Chapter 4 Results Data Repeated testing

6 4.3 Conversion of mean retentive values to megapascals Statistical analysis Two-way ANOVA analysis Post test analysis Data cleaning Null hypothesis Chapter 5 Discussion Method of cement failure Crown copings Abutments Clinical implications Panavia-F specimens KetacCem specimens TempBond NE specimens Comparison to other similar studies Panavia-F KetacCem TempBond NE and TempBond TempBond NE TempBond Conclusions Cement film thickness Abutment screw access channels Abutment screw access channel wax seal Cement failure values and the hang-on effect Sources of potential bias during testing In vitro conditions bias Experimental bias Component construction Cementation 140

7 Thermocycling Compressive cyclic loading Uniaxial tensile testing Cleaning specimens Compressive cyclic loading Cleaning specimens Scanning electron microscopy analysis Experimental limitations Potential clinical relevance 155 Chapter 6 Conclusions Bibliography.. 158

8 STATEMENT This thesis is submitted in partial fulfillment for the requirements for the Degree of Doctor of Clinical Dentistry (Prosthodontics) at the University of Adelaide. This work contains no material that has been accepted for the award of any other degree or diploma in any university or other tertiary institution, and to the best of my knowledge and belief contains no material previously published or written by another person, except where due reference is made in the text of the report. I give consent to this copy of my thesis when deposited in the University Library, being made available for loan and photocopying, subject to the provisions of the Copyright Act James Dudley September 2008

9 Summary Background The cementation of crowns to dental implant abutments is an accepted form of crown retention that requires consideration of the properties of available cements within the applied clinical context. Most current dental cements were developed primarily for use with natural tooth crowns, but must act in a different manner with implant components. Cements are exposed to a number of stressors that may reduce crown retention in vivo, not the least of which is occlusal loading. This study investigated the influence of compressive cyclic loading on the physical retention of cast crown copings cemented to implant abutments. Method Cast crown copings were cemented to Straumann synocta titanium implant abutments with three different readily used and available cements. Specimens were placed in a humidifier, thermocycled and subjected to one of four quantities of compressive cyclic loading. The uniaxial tensile force required to remove the cast crown copings was then recorded. Data analysis was conducted using twoway ANOVA and paired post tests. i

10 Results Statistical analysis arising from post tests following two-way ANOVA testing revealed the mean retention values for crown copings cemented with Panavia-F cement (5.103, 2.681, 3.178, 2.986MPa) were statistically significantly greater than both KetacCem (0.646, 0.701, 1.083, 0.914MPa) and TempBond non eugenol (0.074, 0.181, 0.190, 0.303MPa) cements at each compressive cyclic loading quantity. KetacCem and TempBond non eugenol cements produced relatively low mean retention values that were not statistically significantly different at each quantity of compressive cyclic loading. Compressive cyclic loading had a statistically significant effect on Panavia-F specimens alone, but increased loading quantities produced no further statistically significant difference in mean retention. Compressive cyclic loading had no overriding statistically significant effect on the retention of all specimens as a population. Conclusions Within the limitations of the current in vitro conditions employed in this study, the retention of cast crown copings cemented to Straumann synocta implant abutments with Panavia-F, KetacCem, and TempBond non-eugenol was significantly affected by cement type but not compressive cyclic loading. Panavia-F is the cement of choice for the definitive non-retrievable cementation of cast crown copings to Straumann synocta implant abutments out of the three cements tested. The implications of these results relate to the choice of cement to provide the desired crown coping retention. ii

11 Acknowledgements Professor Lindsay Richards, whose expertise, guidance and positivity has been invaluable throughout my postgraduate study. Associate Professor John Abbott, whose knowledge and willingness to discuss matters at length has provided great support. Victor Marino, for his guidance in the experimental component of this research. Staff at Adelaide Microscopy for their tutelage in the use of the scanning electron microscope. The staff of Clinic 1.4 in the Adelaide Dental Hospital, particularly Amanda and Carol, for their assistance and persistence with mixing cements. I would like to express my sincere appreciation to Straumann Australia for the generous supply of implant components used in this research. Finally, to my wife, Sara, and daughter, Indira, for your endless support, encouragement and patience. iii

12 Abbreviations Ave average CAD-CAM computer-aided design / computer-aided manufacture CTE coefficient of thermal expansion Hz - Hertz IRM Intermediate restorative material ISO International Organization for Standardization kg kilogram MDP - 10-methacryloyloxydecyl dihydrogen phosphate mm - millimetre MPa MegaPascals N Newtons no. number SA surface area SD standard deviation SEM Scanning Electron Microscopy TempBond NE TempBond non-eugenol VBATDT - 6-[N-(4-vinylbenzyl)propylamino]-1,3,5-triazine 2,4-dithione iv

13 SECTION 2 179

14 Article submitted and accepted for publication in the Australian Dental Journal 2008; 53(4) 180