Laboratory Studies
Culture and sensitivity testing and, in selected cases, DNA probe testing may be used to identify the causative organism and determine treatment.
Serious dental infections may increase the erythrocyte sedimentation rate and neutrophil count. With chronic infections, lymphocyte and monocyte counts may subsequently increase.
Imaging Studies
In chronic periapical infections, a well-circumscribed radiolucency may be observed radiographically; however, in early infections, radiographic evidence may not be observed.
On radiographs, osteomyelitis appears as an area of radiolucency, radiopacity, or mixed radiolucency with poorly defined borders. The mandible is most commonly involved. These findings are also present in osteoradionecrosis
Unless the infection is rampant and severe, imaging studies such as a CT scanning or MRI usually are not necessary. If infection persists despite therapy, CT scanning and MRI may be necessary to determine its extent and to rule out a neoplastic cause. Computer-aided rapid prototyping in a 3-dimensional format with CT scans was reported to analyze each tooth root to aid in nonsurgical root canal therapy. [36]
Panoramic radiographs, lateral jaw plain radiographs, Waters radiographs, or periapical radiographs may be necessary for diagnosis and treatment, depending on the location and extent of the infection.
Cone-beam studies may be very beneficial for the diagnosis of dental infections. This technique is excellent to find the exact origin and extent of the infection. More dental offices, and especially oral and maxillofacial surgeons' offices, use cone-beam technology for the following [37] :
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Dental implant placement and evaluation of adequate bone with anatomical structures
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Evaluation of the temporomandibular joints for an aid to diagnoses of temporomandibular disorders
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Examination of teeth and facial structures for orthodontic treatment planning
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Evaluation of extraction of mandibular third molars and the proximity of the inferior alveolar nerve
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Evaluation of teeth and bone for signs of infections, cysts, or tumors
With oral antral and oral nasal fistulas, cloudy sinuses may be observed on panoramic or Waters radiographs. Radiographs occasionally show a break in the antral or nasal floor. If the opening to the palate is large enough, nasal speech occurs.
CT fistulography can be used to help diagnose an orodentocutaneous fistula of dental origin. [38]
Procedures
The possibility of a neoplastic cause may require biopsy.
Histologic Findings
With acute infection, histologic sections show a preponderance of neutrophils and necrotic debris. Chronic infections are histologically characterized by numerous plasma cells, lymphocytes, and macrophages; often, a proliferation of blood vessels and connective tissue or granulation tissue is present.
In chronic osteomyelitis, sections of acellular bone are present, sometimes with little inflammatory infiltrate. When histologic sections are processed, decalcification of the specimen for sectioning can remove lacunar cells present in bone. This effect must be considered when histologic sections of bone are viewed.
Actinomycosis has characteristic pseudohyphae appearing as clublike projections that stretch out from a central basophilic-staining core. The absence of this finding does not rule out an actinomycotic infection.
Microscopic sections of mucoceles show minor salivary glands with chronic inflammation and a granulation wall that surrounds a pool of mucin.
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Cutaneous fistula due to a dental infection that causes Ludwig angina. Courtesy of Alexander Pazoki, DDS, LSU School of Dentistry, New Orleans, La.
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Gunshot wound causing an oral cutaneous fistula. Courtesy of Alexander Pazoki, DDS, LSU School of Dentistry, New Orleans, La.
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Squamous cell carcinoma causing an oral cutaneous fistula. Courtesy of Alexander Pazoki, DDS, LSU School of Dentistry, New Orleans, La.
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Squamous cell carcinoma of the sinus that penetrates the maxillary ridge.
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Clinical view of a parulis with a sinus tract from a fractured mandible.
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Fractured mandible panoramic radiograph.
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Oral cutaneous fistula from a dental infection.
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Mucocele or mucous retention phenomenon lower lip.
