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Updated: Jun 12, 2026

Animal Model of Implant-Associated Infections in Mice
Published on: June 27, 2025
Etiopathogenesis of mandibulofacial and maxillofacial abscesses in mice
1Division of Laboratory Animal Medicine, David Geffen School of Medicine, University of California - Los Angeles, Los Angeles, California, USA. glawson@mednet.ucla.edu
Abstract:
The etiologic agent of mandibulofacial and maxillofacial abscesses in mice is reportedly coagulase-positive Staphylococcus aureus. Although suggested to be through the oral cavity, the exact route of entry has not been documented. Among the clinical cases of mandibulofacial and maxillofacial abscess we report here, each case that was cultured yielded coagulase-positive S. aureus. Histologically, all of the abscesses examined were directly associated with intralesional hair shafts, both vibrissae and pelage, that were introduced into the submucosa via the maxillary or mandibular molar gingival sulci. Grossly, a variable amount of hair was imbedded in the lingual, buccal, or mesial gingival sulci of the maxillary or mandibular molars or both. Computed tomography revealed that the presence of the hair resulted in inflammation and resorption of alveolar bone. With these findings, we propose that mandibulofacial and maxillofacial abscesses are induced by the mastication and fragmentation of hair ingested during the barbering process. From the resulting foreign body periodontitis, abscess formation originates at the maxillary lingual, buccal, or mesial gingival sulci, resulting in infection of the maxillary molar tooth roots with swelling or rupture through the skin inferior to the eye, or at the mandibular lingual, buccal, and or mesial gingival sulci, resulting in infection of the mandibular molar tooth roots and osteomyelitis with drainage through the skin of the ventral mandible.
Insights
Mandibulofacial and maxillofacial abscesses in mice are caused by Staphylococcus aureus. Hair introduced into the gums during grooming leads to inflammation, bone loss, and abscesses.
Area of Science:
- Veterinary Pathology
- Microbiology
- Oral Surgery
Background:
- Mandibulofacial and maxillofacial abscesses in mice are linked to coagulase-positive Staphylococcus aureus.
- The precise route of bacterial entry into the oral cavity remains undocumented.
Purpose of the Study:
- To investigate the etiology and pathogenesis of mandibulofacial and maxillofacial abscesses in mice.
- To identify the route of entry and initiating factors for these abscesses.
Main Methods:
- Histopathological examination of abscess tissues.
- Bacterial culturing from abscess cases.
- Computed tomography (CT) imaging to assess bone involvement.
Main Results:
- Coagulase-positive Staphylococcus aureus was consistently isolated from cultured abscesses.
- Abscesses were histologically associated with intralesional hair shafts in gingival sulci.
- CT scans showed hair-induced inflammation and alveolar bone resorption.
- Hair fragments were observed embedded in gingival sulci of maxillary and mandibular molars.
Conclusions:
- Hair ingestion and fragmentation during barbering likely initiate foreign body periodontitis.
- This process leads to abscess formation originating in gingival sulci, causing tooth root infection and osteomyelitis.
- The findings propose a novel mechanism for abscess development in the maxillofacial region of mice.

