HealthDay News — People with cavities had lower incidence of head and neck cancers, perhaps due to heightened immune activity, study findings indicate.
Dental caries were significantly less common among 399 patients with head and neck cancers than among 221 people without a cancer diagnosis, Mine Tezal, DDS, PhD, of the State University of New York at Buffalo, and colleagues, reported in JAMA Otolaryngology-Head & Neck Surgery.
“To our knowledge, the present study suggests, for the first time, an independent association between dental caries and head and neck squamous cell carcinoma,” they wrote.
Although previous studies involving patients with periodontitis have shown that infections below the gum line may increase cancer risk, Tezal and collegues emphasized that both the etiology and outcome of these two oral disease are distinct, particularly in terms of the bacteria responsible and patients’ immune responses.
Bacteria involved in periodontitis cases often prompt Th2/Th17 immune responses, which “have been generally associated with increased risk of cancer,” whereas cariogenic, lactic-acid producing bacteria associated with dental caries prompt Th1 immune responses that suppress tumor formation.
For the current study, Tezal and colleagues examined records from patients aged older than 21 who were treated in the university’s dental and maxillofacial prosthetics department from 1999 to 2007.
They identified 399 patients who were newly diagnosed with head and neck squamous cell carcinoma and 221 controls that consisted of general dental patients or those with diagnoses ranging from oral warts to traumatic injuries to cysts and abscesses. Patients with a history of cancer, dysplasia or immunodeficiency were excluded from both groups.
The researchers evaluated caries at examination, the presence of crowns or fillings, the number of teeth with endodontic treatments, as well as missing teeth and alveolar bone loss. A blinded examiner also calculated a composite measure of decayed, missing or filled teeth (DMFT) based on panoramic radiographs from patients’ records.
Findings among cases versus controls were as follows:
Number of teeth with caries — 1.58 in cases (SD 2.52) vs. 2.04 in controls (SD 2.15; P=0.03)
Number of crowns — 1.27 in cases (SD 2.65) vs. 2.10 in controls (SD 3.57, P=0.004)
Number of endodontic treatments — 0.56 in cases (SD 1.24) VS. 1.01 in controls (SD 2.04)
DMFT — 16.40 in cases (SD 6.79) vs. 15.39 in controls (SD 6.31, P=0.09)
Alveolar bone loss — 4.03 mm in cases (SD 1.33) vs. 2.44 mm in controls (SD0.93, P<0.001).
Patients with squamous cell head or neck cancer had significantly more missing teeth, but had a significantly lower number of teeth with caries, crowns, endodontic treatments and fillings compared with controls, the researchers found.
Those in the upper tertiles of caries, crowns and endodontic treatments were less likely to have head and neck squamous cell carcinoma than those in the lower tertiles (odds ratios, 0.32, 0.46, 0.55, respectively), after adjustment for age at diagnosis, sex, marital status, smoking status and alcohol use.
However, associations between caries counts and cancer were only significant among patients with tumors of the oral cavity and oropharynx (both P<0.001 for trend). For laryngeal cancer, there were no differences in caries counts between cases and controls (P=0.67). No significant differences were noted between the groups on DMFT composite scores.
“There is an inverse association between head and neck squamous cell carcinomas and dental caries,” the researchers concluded. “This study provides insights for future studies to assess potential beneficial effects of lactic acid bacteria and the associated immune response on [these types of cancers].”