Obesity is a common issue. It can be treated in some cases through surgery. While this can be highly effective for losing weight, adverse effects are possible. Now, new research is looking into the effects of obesity surgery on oral health has taken place. There are concerning findings, which suggest that obesity surgery can worsen the oral health of anyone undergoing the procedure.

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Obesity is a growing problem in society, which is causing problems for patients, the healthcare industry, and policy makers around the world.

When people are obese, there are various surgeries that they can undergo which can improve their physical condition and overall wellbeing.

However, recent research has shown that there could actually be a negative side effect to such surgeries – in the form of a subsequent increased risk of dental cavities [1]. This is an important consideration when deciding treatment methods for obesity.


Someone with obesity will typically have excess body fat. Obesity goes beyond being overweight.

The statistics surrounding obesity are deeply concerning. It is a growing problem in society, with a recent global study predicting that more than half of the global population will be either overweight or obese by 2035 [2].

Moreover, the World Health Organization reports that rates of obesity have almost trebled since 1975 [3]. Evidently, it is a growing issue that needs to be addressed.

Obesity increases the risks of many other health conditions, including Type 2 Diabetes, Heart Disease, Stroke, and some cancers [3].

A change in lifestyle and diet are the most effective way of tackling obesity. However, surgery options like gastric bypass surgery exist. While surgery can be effective, there is the potential for adverse effects afterwards, as the aforementioned research has identified.

The research

Research conducted by a team from the University of Gothenburg in Sweden looked into the oral health of individuals before and after treatment for severe obesity [1].

In Sweden, obesity is a growing problem. For example, there are approximately 5,000 obesity surgeries carried out each year [1].

The study involved 118 obese individuals. All participants in the study had a BMI score of 40 or more, or 35 or more when combined with other medical conditions [1]. BMI is a method of measuring a person’s height to weight ratio, which can calculate if they are in a healthy weight range. Anyone with a BMI score of over 30 is considered obese.

The team collected information both pre-surgery and post-surgery on the oral health of participants [1]. In terms of post-surgery, the research team caught up with participants two years after their surgery. These results were then compared.

The team had hoped to see an improvement in oral health after surgery, but this didn’t materialize. Instead, there were very minor differences, and in several cases, oral health had actually worsened.

Interestingly, the more obese a person was pre-surgery, the worse their oral health tended to be [1]. This could be explained by obese people usually consuming high levels of high-calorie and high-sugar food.

This was demonstrated by finding that as people were more obese, they had an increasing number of cavities [1]. However, this only changed a negligible amount following the surgery.

Moreover, the initial tests found high scores for both dental plaque (50.2%) and gingivitis (34.5%) – which is a mild form of gum disease [1]. This showed that obese people have higher rates of oral health problems.

Post-surgery, the researchers found that a common adverse effect was hyposalivation [1]. This results in a dry mouth, which reduces saliva flow. This is known to cause several oral health problems, including an increased risk of tooth decay.

Moreover, the researchers found that on average, there was an increase in tooth decay by 0.59 per tooth surface following the surgery [1]. Therefore, there was an increased chance of developing cavities post-surgery.

Also, the follow-up also found that participants largely had poor self-perceived oral health – with 45% of participants rating their oral health quality as being low [1].

Overall, the findings were rather disappointing. It seemed that there were many negative results in terms of the oral health of participants post-surgery.

What this means

There were many physical health benefits for participants. However, this didn’t protect against the negative impact on oral health. The findings suggest that if anything, obesity surgery can worsen oral health.

Dry mouth appears to be a side effect of surgery. This is known to cause many oral health problems. But what about the other causes of the decline in oral health?

It could be argued that for many obese people, that there are long-ingrained habits which can take time to change. Furthermore, there are often underlying health problems or medicines that can contribute to weight gain. For example, common medicines like antidepressants and antipsychotics are known to be associated with weight gain [4].

This shows that there are many factors in play with this complex subject. The authors also pointed out that other research has showed that those receiving medical treatment for obesity rather than surgery, had seen tooth decay decrease.

It is important for everyone to look after their oral health. But for those who are obese, or are considering surgery, it is crucial to take extra care with oral health.

Thinking points…

1) An increase in tooth decay can affect anyone, especially if sugar consumption increases. It is important to look after your oral health! An important part of this is attending a dental clinic for a check-up regularly. At a check-up, a dentist can examine your oral health and provide advice and treatment information if needed. We recommend booking an appointment now!

2) Do you know anyone who has undergone or is undergoing any form of surgery for weight loss? If so, you could share this article with them now. It will give them crucial information on their oral health, and aid their wider health and wellbeing. We recommend sharing this article now!

What we offer at Taradale Dental

Taradale Dental is a Calgary dental clinic that provide its patients with a wide range of dental treatment options and advice aimed at improving their oral health.

We advise our patients to attend our Calgary-based dental clinic twice a year for a regular dental check-up. When problems are detected, we have many treatments available. For instance, these include cavity fillings and root canals. To try and prevent problems, it is important to brush your teeth at least twice a day and floss regularly.

Here at Taradale Dental, we also have some cosmetic treatments available! These include dental implants, tooth whitening and Invisalign™! Many people find that these treatments have a positive impact on their appearance, confidence and self-esteem.

In addition, all of our services at our Calgary dental clinic Taradale Dental are in line with the Alberta Dental Fee Guide.

We would love you to visit our Taradale Dental clinic in Calgary! You can find out more about us by visiting our website https://taradaledental.ca.


[1] Taghat, N., Werling, M., Östberg, AL. (2020). Oral Health–Related Quality of Life After Gastric Bypass Surgery. Obesity Surgery. 30. p224–232. DOI: https://doi.org/10.1007/s11695-019-04172-0.

[2] World Obesity. (2023). Econimic impact of overweight and obesity to surpass $4 trillion by 2035. Available: https://www.worldobesity.org/news/economic-impact-of-overweight-and-obesity-to-surpass-4-trillion-by-2035. Last accessed: 8th November 2023.

[3] World Health Organization. (2021). Obesity and overweight. Available: https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight. Last accessed: 8th November 2023.

[4] Himmerich, H., Minkwitz, J., Kirby, C. K. (2015). Weight Gain and Metabolic Changes During Treatment with Antipsychotics and Antidepressants. Endocrine, Metabolic & Immine Disorders-Drug Targets. 15 (4): p252-260. DOI: https://doi.org/10.2174/1871530315666150623092031.