Handbook of Oral Pathology and Oral Medicine. S. R. Prabhu

on the occlusal surfaces of mandibular permanent first molars.(source: images by kind permission of Professor Charles Dunlap, Kansas City, Kansas, USA.)

1.18 Tooth Ankylosis: Key Features

       Anatomical fusion of tooth cementum with the alveolar bone:Mandibular primary first molars are frequently ankylosedAnkylosis of permanent teeth is uncommonA sharp solid note on percussion is noted, suggesting ankylosisPeriodontal ligament space is absent on radiographyIn many examples, the permanent successor is missingFigure 1.16 An extracted mandibular molar with three roots.

1.19 Supernumerary Roots: Key Features

       Normally, the permanent mandibular first molar has two roots, one mesial and one distal root

       Rarely, an additional third root is seen, which is found distolingually, called the radix entomolaris (Figure 1.16)

       Occasionally, supernumerary roots may be detected in mandibular third molars, mandibular canines and premolars

       No treatment is required

       Detection is critical for endodontic treatment

Recommended Reading

      1 Consolaro, A., Hadaya, O., Oliveira Miranda, D.A., and Colsolaro, R.B. (2020). Concrescence: can the teeth involved be moved or separated? Dental Press Journal of Orthodontics 25 (1): 20–25.

      2 Miletich, I. and Sharpe, P.T. (2003). Normal and abnormal dental development. Human Molecular Genetics 12 (Suppl 1): R69–R73.

      3 Neville, B.W., Damm, D.D., Allen, C.M., and Chi, C.A. (2016). Developmental alterations of teeth. In: Oral and Maxillofacial Pathology, 4ee, 49–92. St. Louis, MO: Elsevier.

      4 Odell, E.W. (2017). Disorders of tooth development. In: Cawson's Essentials of Oral Pathology and Oral Medicine, 9ee, 23–42. Edinburgh: Elsevier.

      5 Parsa, A. and Rapala, H. (2016). Endodontic treatment of a mandibular 6 years molar with three roots: a pedodontist perspective. International Journal of Pedodontic Rehabilitation 1: 64–67.

      6 Rhoads, S.G., Hendricks, H.M., and Frazier‐Bowers, S.A. (2013). Establishing the diagnostic criteria for eruption disorders based on genetic and clinical data. American Journal of Orthodontics and Dentofacial Orthopaedics 144 (2): 194–202.

      7 Rosa, D.C.L., Simukawa, E.R., Capelozza, A.L.A. et al. (2019). Alveolodental ankylosis: biological bases and diagnostic criteria. RGO Revista Gaúcha de Odontologia 67: e2019003.

      8 Seow, W.K. (2014). Developmental defects of enamel and dentine: challenges for basic science research and clinical management. Australian Dental Journal 59 (1 Suppl): 143–154.

2 Dental caries

      CHAPTER MENU

      1  2.1 Definition/Description

      2  2.2 Frequency

      3  2.3 Aetiology/Risk Factors/Pathogenesis

      4  2.4 Classification of Caries

      5  2.5 Clinical Features

      6  2.6 Differential Diagnosis

      7  2.7 Diagnosis

      8  2.8 Microscopic Features

      9  2.9 Management

      10  2.10 Prevention

2.1 Definition/Description

       Dental caries is an infectious, transmissible disease resulting in destruction of tooth structure by acid‐forming bacteria found in dental plaque (an intraoral biofilm) in the presence of fermentable carbohydrates

       The infection results in the loss of tooth minerals that begins with the outer surface of the tooth and can progress through the dentin to the pulp, ultimately compromising the vitality of the tooth

2.2 Frequency

       60–90% of schoolchildren worldwide; the disease is most prevalent in Asian and Latin American countries

2.3 Aetiology/Risk Factors/Pathogenesis

       Biofilm acid‐producing bacteria metabolize sugars and produce acids that lower the biofilm pH creating conditions that demineralize tooth enamel and dentin

       Acid‐producing bacteria are Mutans streptococci and Lactobacillus species

       Acids produced include lactic, acetic, formic and propionic acids. These acids are capable of demineralizing enamel and dentin

       Cycles of demineralization and remineralization continue in the mouth in the presence of cariogenic bacteria, fermentable carbohydrates and saliva

       Plaque microorganisms, substrate, susceptible tooth and time are essential factors for the development of caries

2.4 Classification of Caries

       Classification is based on:Rate of progression: acute and chronic cariesAffected dental hard tissues: enamel, dentin and cemental (root surface) cariesLocation on the tooth surface involved: pit and fissure caries, approximal/smooth surface caries and root surface caries (Table 2.1)Table 2.1 American Dental Association caries classification system: Site Definitions‐OriginSource: Based on Ismail, A.I., Tellez, M., Pitts, N.B. et al. (2013). Caries management pathways preserve dental tissues and promote oral health. Community Dentistry and Oral Epidemiology 41 (1): e12–e40.SiteDefinitionPit and fissureThe anatomical pits or fissures (clefts or valleys in the tooth surface) of the teeth at the occlusal, facial or lingual surfaces of posterior teeth OR the lingual surfaces of the maxillary incisors or caninesApproximal surfaceThe contact point(s) between adjacent teethCervical and smooth surfaceThe cervical area or any other smooth enamel surface of the anatomic crown adjacent to an edentulous space (toothless space); may exist anywhere around the full circumference of the toothRootThe root surface apical to the anatomic crown

2.5 Clinical Features

       Asymptomatic in the initial stages

       Mild pain, tooth sensitivity when carious lesion gets larger

       Visible cavity in the tooth