The correlation between different techniques for the evaluation of oral malodour in children with and without orthodontic treatment

Aim The aim of this work was to evaluate the correlation between different methods (organoleptic evaluation, gas chromatography, salivary β-galactosidases activity) for the evaluation of halitosis in children. The secondary purpose was to investigate the influence of orthodontic treatment on halitosis. Materials and methods Study Design: Oral malodour was detected with different methods in 50 children in the Paediatric Dentistry Unit, University of Rome Tor Vergata, Rome, Italy. During the dental visit, level of oral hygiene, tongue coating scores and presence of an orthodontic device, fixed or mobile, were recorded. Two trained and calibrated operators performed the organoleptic evaluation; the Oral ChromaTM device was used for the volatile sulfur compounds (VSCs) quantification and salivary β-galactosidases (Sβ-g) activity was evaluated through the spectrophotometric method. Statistics: The Cohen’s Kappa score was used to evaluate the level of agreement between the operators. The Pearson’s correlation coefficient was used to evaluate the linear relationship between continuous variables (e.g. Sβ-g vs. VSCs values) and the Spearman’s correlation coefficient was calculated for ordinal variables (e.g. organoleptic scores) vs. other parameters. The LSD test was used to compare the parameters analysed in the study. Results A positive and significant correlation between the organoleptic evaluation, the Sβ-g, the levels of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) was found. The Spearman’s correlation has shown that organoleptic scores were significantly correlated with Sβ-g (0.664, p<0.001) and the Oral ChromaTM measurements of H2S (0.538, p<0.001) and Ch3SH (0.316, p=0.026). The Pearson’s correlation showed that Sβ-g was statistically significantly correlated with the Oral ChromaTM measurements of H2S (0.379 p=0.007) and Ch3SH (0.299, p=0.0035). Stratifying results for orthodontic treatment, it was possible to show that children under orthodontic treatment, both fixed or removable, were characterised by higher level of Sβ-g. The organoleptic evaluation and Oral ChromaTM measurements showed that children wearing fixed orthodontic were characterised by higher scores. Conclusions There was a significant correlation between the three different techniques for the evaluation of oral malodour in children. Like in the adult population, the increase of Sβ-g activity was associated with oral malodour. The presence of fixed orthodontic appliances was correlated to increased scores of all methods for the evaluation of halitosis.