Open Access Highly Accessed Research article

Changes in pharyngeal aerobic microflora in oral breathers after palatal rapid expansion

Angela Pia Cazzolla1, Giuseppina Campisi2*, Grazia Maria Lacaita1, Marco Antonino Cuccia2, Antonio Ripa1, Nunzio Francesco Testa1, Domenico Ciavarella3 and Lorenzo Lo Muzio3

Author Affiliations

1 Department of Dentistry ad Surgery, University of Bari, Bari, Italy

2 Department of Dental Sciences "G. Messina", University of Palermo, Palermo, Italy

3 Department of Surgical Sciences, University of Foggia, Foggia, Italy

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BMC Oral Health 2006, 6:2  doi:10.1186/1472-6831-6-2

Published: 21 January 2006



The purpose of this study was to investigate in oral breathing children the qualitative and quantitative effects on aerobic and facultatively anaerobic oropharyngeal microflora of respiratory function improved by rapid palatal expansion (RPE).


In an open clinical trial, we studied 50 oral breathers, aged 8 to 14 years and suffering from both maxillary constriction and posterior cross-bite. At baseline, patients were examined by a single otorhinolaryngologist (ENT), confirming nasal obstruction in all subjects by posterior rhino-manometric test. Patients were evaluated three times by oropharyngeal swabs:1) at baseline (T = 0); 2) after palatal spreading out (T = 1); and 3) at the end of RPE treatment (T = 2). With regard to the microbiological aspect, the most common and potentially pathogenic oral microrganisms (i.e. Streptococcus pyogenes, Diplococcus pneumoniae, Staphylococcus aureus, Haemophilus spp, Branhamella catarrhalis, Klebsiella pneumoniae, Candida albicans) were specifically detected in proper culture plates, isolated colonies were identified by means of biochemical tests and counted by calibrated loop. The data were analyzed by means of the following tests: Chi-square test, Fisher's exact test and Wilcoxon's test.


After the use of RME there was a statistically significant decrease of Staphylococcus aureus stock at CFU/mLat T1(P = 0.0005; Z = -3,455 by Wilcoxon Rank test) and T2 (P < 0.0001; Z = -4,512 by Wilcoxon Rank test) vs T0. No significant changes were found for the other examined microrganisms.


Our data suggest that RPE therapy in oral breathers may strongly reduce the pathogenic aerobic and facultatively anaerobic microflora in the oral pharynx after a normalization of the upper airways function, and may reduce the risk of respiratory infections.