After obesity surgeries, some patients may experience badbreath (halitosis). This is often mistakenly thought tooriginate from the stomach. However, anatomically, there isa significant distance between the stomach and the mouth,making it impossible for odors to travel from the stomach tothe mouth. The cause of bad breath originates from the oralcavity. Halitosis primarily results from the decay effects ofmicroorganisms in the mouth on endogenous (internallysourced) or exogenous (externally sourced) proteins andpeptides. Oral causes such as coating on the tonguesurface, periodontal diseases, or gum problems can lead tothis condition. In addition, non-oral halitosis may result fromconditions in the upper and lower respiratory tracts ormetabolic changes.

Many microorganisms naturally live in various parts of ourbody without causing harm. These microorganisms arereferred to as flora. The oral flora can be affected bynumerous factors, including dietary changes. After surgery,patients undergo significant dietary modifications. When thefood sources for the bacteria living in the mouth change,alterations in the oral flora occur.

Changes in diet during the postoperative period, decreased salivary flow, and increased acidity due to frequent vomiting episodes facilitate the emergence of oral symptoms. These factors lead to qualitative and quantitative changes in the microbial composition of the oral flora, affecting the microbial structure of dental plaque. Such changes can promote the growth of certain oral bacteria, particularly species like Porphyromonas gingivalis, thereby triggering the development of halitosis.

Studies have shown that in the first month following sleeve gastrectomy, there is an increase in the plaque index (PI), gingival index (GI), and the presence of P. gingivalis, along with elevated concentrations of volatile sulfur compounds (VSCs). However, it has been reported that these parameters significantly improve by the third and sixth months.

The tongue surface consists of a complex structure formed by desquamated epithelial cells, leukocytes from periodontal pockets, food debris, and bacteria. The depth of the tongue’s papillae influences the amount of biofilm coating, reducing the cleansing effect of salivary flow and allowing the proliferation of anaerobic bacteria. This condition can lead to halitosis even in individuals with healthy periodontal tissues and good oral hygiene.

Nutritional deficiencies observed after bariatric surgery can lead to vitamin C, D, and B12 deficiencies in the short and long term. Various studies have shown that vitamin deficiencies negatively impact gum health and the oral microbial flora. Halitosis is a condition that can be observed starting from the third month but typically shows a tendency to improve after the sixth month. To prevent it, adequate fluid intake to increase salivary flow, addressing vitamin and mineral deficiencies, and maintaining good oral hygiene are essential.

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