University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 8-1996 The Cementoenamel Junction: Gap, Overlay and Edge to Edge Relationships Elizabeth A. Gilb University of Tennessee, Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Anthropology Commons Recommended Citation Gilb, Elizabeth A., "The Cementoenamel Junction: Gap, Overlay and Edge to Edge Relationships. " Master's Thesis, University of Tennessee, 1996. https://trace.tennessee.edu/utk_gradthes/4128 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Elizabeth A. Gilb entitled "The Cementoenamel Junction: Gap, Overlay and Edge to Edge Relationships." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Master of Arts, with a major in Anthropology. Murray Marks, Major Professor We have read this thesis and recommend its acceptance: Richard Jantz, William M. Bass, David Gerard Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a thesis written by Elizabeth A. Gilb entitled "The Cementoenamel Junction: Gap, Overlay and Edge to Edge Relationships." I have examined the finalcopy of this thesis forform and content and recommend that it be accepted in partial fulfillmentof the requirements forthe degree of Master of Arts, with a major in Anthropology. We have read this thesis and omm&id�s·acceptance: ACKNOWLEDGEMENTS I would like to thank my committee members, Dr. MurrayMarks, Dr. William Bass, Dr. Richard Jantz and Dr. David Gerard for all of their help, encouragement and supportduring my research. I would like to give specialthanks to Dr. Gerard who allowed me to use his equipment in analyzing my thin section samples and for all of his many questions that helpedme to formulatemy thoughts. To Dr. Murray Marks who always greeted me with a smile and words of encouragement when I need them, I would like to say thank you for all of your help in teaching me how to become a valuable researcher and how to produce the perfect thin section. Believe it or not I will miss all of those hours in the lab working on making epoxy molds for the teeth and the many hours spent in frontof the thin sectioning saw. I really appreciate all of the time and effectyou put into my project and helping me finallyachieve my goal. To my familyand friends, I would like to say thank you all for believing in me and not letting me throw in the towel when things got to be to much. Cathy, thank you so much forbeing my best friendand always telling me that I am smart. I would also like to thank Fran Wheatley who has been there forme through thick and thin and who has never let me forgetthe importantthings in life,such as having a great friendlike her. Fran, I wish you the best and know that we will always be close friends. I must give specialthanks to Robert Kelly who has been a very positive influencein my life. He has taught me to have confidencein myself, to love myself and most of all to fulfillall of my hopesand dreams. Robert, thank you forgiving me a shoulder to cryon and most of all for being there for me. I love you. ii DEDICATION I would like to dedicate the followingMaster's thesis to my niece Marley Siobahn Gilb who has been a wonderful influencein my lifeand who has taught me about unconditional love. I regret ever leaving you and going to graduateschool. Some day I hope that you will understand how important you really are to me. I love you. iii ABSTRACT The purposeof this research is to examine mineralized tissue relationships at the cementoenameljunction in the maxillarycentral incisor and the mandibular canine. There are three distinct relationships at the cervical region of the tooth: a gap junction is when the cementum and enamel failto connect, an edge-to-edge when the cementum and enamel meet and an overlay when the cementum extendson to the enamel. There are fourmain research questions that have been addressed in this investigation; 1) Can a type ofjunction be correlated to racial affinity? 2) Is there a relationship between sex andjunction type? 3) Is there a significantdifference between adults and children? 4) Does dental hygiene or exposure to the oral cavity cause changes or damage to this structure? Population samples were utilized froma modem, historic and prehistoric time periodsto address the above questions. Thin sections were analyzed at a magnificationof 125X. The results verifieda strongrelationship between racial affinityand junction type. Sex was correlated to junction typeon the labial surface of the canine only, while age and junctiontype showed positivestatistical results forthe both labial and lingual incisor. Dental hygiene and exposure ( via age) to the oral cavity does not seem to result in a significantchange at the cervical margin of the tooth. The goal of this research was to aid physical/forensicanthropologist in determininga biological profileof unknown individuals. iv TABLE OF CONTENTS CHAPTER PAGE 1. INTRODUCTION ................................................................................. 1 2. DENTAL DEVELOPMENT AND TOOTH HISTOLOGY ................. 6 CrownFonnation ................................................................................. 6 Root Formation ..................................................................................... Propertiesand Functions of Enamel ..................................................... 11 Propertiesand Functions of Cementum ............................................... 13 Studies of the Cementoenamel Junction .............................................. 15 3. MATERIALSAND METHODS .......................................................... 25 Materials ............................................................................................... 25 Methods ................................................................................................ 30 4. RESULTS ............................................................................................ 31 Frequency Table Results ...................................................................... 31 Chi Square Test oflndependencefor Sex ........................................... 32 Chi Square Test of Independence forAge .......................................... .. 35 Chi Square Test oflndependencefor Race ........................................ .. 37 5. DISCUSSION ...................................................................................... 46 6. CONCLUSION .................................................................................... 50 BIBLIOGRAPHY ........................................................................................ 52 VITA 60 LIST OF FIGURES FIGURE PAGE 1. Cross-section of the bell stage of tooth development 8 2. Root sheath development and eptihelial diaphragm formation ............. 10 3. Developmental stages of cementum ...................................................... 12 4. Relationships at the cementoenamel junction ....................................... 16 5. A gap relationship viewed under a light microscope at 125X ............... 17 6. An overlay relationship viewed under a light microscopeat 125X ........ 18 7. An edge-to-edge relationship viewed under a light microscope at 12X .. 19 LIST OF TABLES TABLES PAGE 1. Percentage frequenciesof past studies ................................................. 24 2. Frequency table of the labial incisor .................................................... .. 33 3. Frequency table of the lingual incisor .................................................. .. 33 4. Frequency table of the labial canine ...................................................... 34 5. Frequency table of the lingual canine ................................................... 34 6. Chi square results of the labial canine forthe variable sex .................. .. 36 7. Chi square results of the labial canine showing overall percentages ·.... 36 8. Chi square results of the labial incisor forthe variable age .................. .. 38 9. Chi square results of the labial incisor showing overall percentages ... 38 IO. Chi square results of the lingual incisor forthe variable age ............. .. 39 11. Chi square results of the lingual incisor showing overall percentages .. 39 12. Chi square results of the labial incisor forthe variable race ................ 41 13. Chi square results forthe labial incisor showing overall percentages .. 41 14. Chi square results of the lingual incisor forthe variable race ............ .. 42 15. Chi square results of the lingual incisor showing overall percentages .. 42 16. Chi square results of the labial canine forthe variable race ............... .. 43 17. Chi square results of the labial canine showing overall percentages .. 43 18. Chi square results of the lingual canine forthe variable race ............... 44 19. Chi square results of the lingual canine showing overall percentages .. 44 CHAPTER 1 INTRODUCTION A fundamental aspect of skeletal