Abstract
<jats:p>Tooth morphology provides the anatomical substrate on which periodontal biofilms mature, inflammation propagates, and treatment success is constrained. This chapter synthesizes evidence and mechanisms linking crown–root anatomy to site-level susceptibility in periodontitis. The macroanatomic determinants that influence these processes include the contour and emergence profile of the cervical crown, the contact areas and embrasure form, the root length and curvature, the number and divergence of roots, and the dimensions of the root trunk. These determinants shape the cleanability of the teeth and affect the areas where plaque stagnates and where pockets persist. The presence of microanatomic features, such as CEJ irregularities, enamel projections and pearls, developmental grooves, and root concavities, has been observed to promote calculus retention, limit instrumentation, and can produce localized patterns of accelerated attachment loss. The study places particular emphasis on furcation morphology, exploring how entrance size, interradicular anatomy, and trunk length affect detection, prognosis, and regenerative potential. The chapter translates these anatomic risk factors into a practical clinical workflow, which includes targeted probing, morphology-aware interpretation of radiographs and CBCT when indicated, site-level risk stratification, and treatment planning that aligns access, defect architecture, and maintenance intensity with anatomic complexity. Integrating morphology with contemporary concepts of dysbiosis, host response, and biomechanics enables clinicians to enhance the early identification of high-risk sites, establish realistic regenerative expectations, and personalize supportive periodontal care.</jats:p>