Chapter 34 Dentoalveolar infections
Dentoalveolar infections can be defined as pus-producing (or pyogenic) infections associated with the teeth and surrounding supporting structures, such as the periodontium and the alveolar bone. Other terms for these conditions include periapical abscess, apical abscess, chronic periapical dental infection, dental pyogenic infection, periapical periodontitis and dentoalveolar abscess. The clinical presentation of dentoalveolar infections depends on the virulence of the causative microorganisms, the local and systemic defence mechanisms of the host, and the anatomical features of the region. Depending on the interactions of these factors, the resulting infection may present as:
A dentoalveolar abscess usually develops by the extension of the initial carious lesion into dentine, and spread of bacteria to the pulp via the dentinal tubules (Figs 34.1 and 34.2). The pulp responds to infection either by rapid acute inflammation involving the whole pulp, which quickly becomes necrosed, or by development of a chronic localized abscess with most of the pulp remaining viable. Other ways in which microbes reach the pulp are:
Once pus formation occurs, it may remain localized at the root apex and develop into either an acute or a chronic abscess, develop into a focal osteomyelitis, or spread into the surrounding tissues (Figs 34.2 and 34.3).
|Site of spread||Maxillary teeth||Mandibular teeth|
|Palate||Palatal roots of premolars and molars; also lateral incisors with a palatally curved root||–|
|Buccal space||Canines, premolars and molars||Canines, premolars and molars|
|Infraorbital/periorbital region||Canines mainly||–|
|Maxillary sinus||Canines, premolars and molars||–|
|Upper lip||Central and lateral incisors||–|
|Masseteric space, pterygomandibular space, lateral pharyngeal space||–||Lower third molars|
|Lower lip||–||Incisors and canines|
|Submandibular space||–||Root apices below insertion of mylohyoid – usually molars but can also be premolars|
|Submental space||–||Incisors and canines|
|Sublingual space||Root apices above mylohyoid/geniohyoid – usually incisors, canines and premolars; rarely molars|
Clinical features may include a non-viable tooth with or without a carious lesion, a large restoration, evidence of trauma, swelling, pain, redness, trismus, local lymph node enlargement, sinus formation, raised temperature and malaise. The latter two symptoms are a direct consequence of increased levels of systemic inflammatory cytokines such as interleukins and tumour necrosis factor in response to bacterial products such as lipopolysaccharides (i.e. endotoxins).
The common species isolated from dentoalveolar abscesses are Prevotella, Porphyromonas and Fusobacterium spp., and anaerobic streptococci; facultative anaerobes are the second largest group, e.g. Streptococcus milleri (Table 34.2). There is evidence that some strictly anaerobic bacteria, especially Porphyromonas gingivalis and Fusobacterium spp., are more likely to cause severe infection than other species, and that synergistic microbial interactions play an important role in the severity of dentoalveolar abscesses.