USE Root Morphology - An Introduction - Dr Casper Jonker (2023-24).pdf.docx

Root morphology of the human dentition Casper Jonker B.Ch.D, PGDip.Dent, MSc, PGCert (ClinEd), AFHEA, MAcadMed, PhD Intended Learning Outcomes By the end of this session the student will be able to: Recall embedded knowledge of tooth structure. Recall embedded knowledge of the pulp and pulp physiolo...

Root morphology of the human dentition Casper Jonker B.Ch.D, PGDip.Dent, MSc, PGCert (ClinEd), AFHEA, MAcadMed, PhD Intended Learning Outcomes By the end of this session the student will be able to: Recall embedded knowledge of tooth structure. Recall embedded knowledge of the pulp and pulp physiology. Understand root morphology of primary and permanent teeth and its complexity. Condensed revision: the pulp Images: Gu et al. 2009 Images: Cohen et al. 2006 Functions of the pulp Maintain health of dentine (nutrition). Path for sensory impulses (sensory). Initiates and govern dentine repair (formative). Defence: triggers inflammatory and immune response. Protection: secondary and tertiary dentine. Image: Creanor, 2016 Root formation Glossary of terms Development of the tooth root starts following crown formation Once the enamel tissue has reached the future cementoenamel junction (enamel and cementum junction): anatomical boundary between the crown and the root The apical region of the enamel organ elongates and gives rise to the HERS (bilayer epithelial structure: glossary) The HERS then grows apically: guides root formation determining the size, shape and number of tooth roots CNC-derived mesenchyme: condenses around and continuously interacts with the HERS Mesenchyme of the apical papilla comes into contact with the inner layer of the HERS: differentiation into odontoblasts with secretion radicular (root-covering) dentine Root morphology: permanent teeth Maxillary teeth Mandibular teeth Third molars will not be discussed as this will form part of other/later teachings. Findings in literature can differ slightly due to research techniques used and populations involved. Root morphology Maxillary teeth Mandibular teeth Root morphology: primary teeth The primary-permanent relationship Images: Wheeler’s Dental Anatomy, Physiology, and Occlusion General differences between Adult/Permanent teeth Anatomy Splayed, thin roots More elastic bone Differences between roots The roots tend to be shorter and more delicate than permanent teeth. The roots of the primary incisors and canines are longer in proportion to their crown height than corresponding permanent teeth. The roots of the primary molars are widely divergent and usually extend beyond the dimensions of the crown. Image: Cleghorn et al. 2010 The resorbtion process Maxillary central incisors Mandibular central incisors Images: Wheeler’s Dental Anatomy, Physiology, and Occlusion Clinical image: Dr. C Jonker The resorbtion process (2) Maxillary lateral incisors Maxillary canines Images: Wheeler’s Dental Anatomy, Physiology, and Occlusion Morphological varieties Additional roots on molars Radix Entemolaris Morphological phenomenon of an additional disto-lingual root on lower molars. Radix Paramolaris Morphological phenomenon of an additional root on the mesio-buccal side of lower molars. Image: Versiani, Basrani, Sousa-Neto, 2019 Images: Souza-Flamini et al. , 2014 Radix Mesiolingualis Additional root on mesio-palatal side of upper molars. Radix Distolingualis Additional root on disto-palatal side of upper molars. Image: Versiani, Basrani, Sousa-Neto, 2019 Taurodontism The body of the tooth is enlarged, but roots are small. Apically displayed root bifurcations or trifurcations. Images: Versiani, Basrani, Sousa-Neto, 2019 Dilacerated roots Image: Versiani, Basrani, Sousa-Neto, 2019 Clinical implications Endodontics Definition Removal of infected or inflamed tissues inside the tooth with specialised equipment and irrigation solutions. * Teachings on endodontics will be covered in more depth in the future depending on the scope of practice. Clinical case: Dr. Casper Jonker Challenging endodontics Image: Versiani, Basrani, Sousa-Neto, 2019 Clinical case: Dr. Casper Jonker Exodontia Definition Component of dentistry that involves the removal of teeth from the existing dentition. * Teachings on exodontia will be covered in more depth in the future depending on the scope of practice. Primary dentition Clinical image: SDLE Clinical image: SDLE Challenging extractions Image: Versiani, Basrani, Sousa-Neto, 2019 Clinical case: Dr. Casper Jonker Summary: The morphology of roots is very important considering their function and clinical relevance. A variety of morphological appearance can exist. A sound knowledge base of normal and abnormal findings is important for diagnosis and treatment planning. Expect the unexpected. References Versiani MA, Sousa-Neto MD, Basrani B (2019). The root canal dentition in permanent dentition. Online edn. Cham: Springer. Creanor, S. (Ed.) (2016). Essential clinical oral biology. John Wiley & Sons, Incorporated. Cohen S, Hargreaves K, Keiser K (2006): Pathways of the pulp, ed 9, St Louis, Mosby. Wheeler’s Dental Anatomy, Physiology, & Occlusion, tenth edition, Saunders. Cleghorn BM, Boorberg, NB, Christie WH. (2010). Primary human teeth and their root canal systems. Endodontic topics, 23(1), 6-33. Gu, MS, Wei X, Ling J, Huang, X, MSA Microcomputed Tomographic Study of Canal Isthmuses in the Mesial Root of Mandibular First Molars in a Chinese Population. (J Endod 2009;35: 353–356. Souza-Flamini, L.E., Leoni, G.B., Chaves, J.F.M., Versiani, M.A., Cruz-Filho, A.M., Pécora, J.D. and Sousa-Neto, M.D., 2014. The radix entomolaris and paramolaris: a micro–computed tomographic study of 3-rooted mandibular first molars. Journal of Endodontics, 40(10), 16161621. Li J, Parada C, Chai Y. Cellular and molecular mechanisms of tooth root development. Development. 2017 Feb 1;144(3):374-384.