Most people notice bad breath at some point, and for many, it clears up quickly after brushing. When it keeps coming back, though, it can be a sign that something in your mouth, or occasionally elsewhere in the body, needs attention.
At Kellyville-based dental clinic, Dr Hiromi Matsuoka takes the time to understand each patient’s situation fully before discussing any options. Persistent bad breath is one of the more common concerns she sees at our general dental check-up and clean appointments, and in most cases, it is traceable to a specific, addressable cause.
Quick Overview
- Bad breath, also called halitosis, is an unpleasant odour from the mouth that may be temporary or ongoing
- It may affect anyone, though it is often linked to oral hygiene habits, dry mouth, gum conditions, or certain foods
- Addressing the underlying cause may help reduce or resolve it, though what works varies between individuals
- Several factors, including saliva flow, tongue coating, and the presence of gum disease, influence how persistent bad breath becomes
- A dental check-up is often the starting point for identifying what is driving the odour
The sections below outline the most common bad breath causes, how they work, and what a dentist can assess.
What Is Bad Breath (Halitosis)?
Bad breath, known medically as halitosis, refers to an unpleasant odour in exhaled breath. Halitosis is normal first thing in the morning, when it typically clears after brushing. Bad breath that continues throughout the day may point to a dental issue or another health condition worth investigating.
The odour itself usually comes from bacteria in the mouth breaking down food particles and proteins. This process releases volatile sulphur compounds, which are responsible for the unpleasant smell. Most cases originate in the oral cavity, though some have causes elsewhere in the body.
What Are the Most Common Bad Breath Causes?
The majority of halitosis cases are linked to oral factors. The primary causes include sulphur-producing bacteria on the tongue and in the throat, dental issues such as gum disease, and dry mouth.
The most frequently identified causes include:
- Poor oral hygiene: When teeth are not brushed and flossed regularly, food particles remain in the mouth and feed odour-producing bacteria. Bacteria also collect in dental plaque along the gum line and between teeth.
- Gum disease: Infection and inflammation of the gum tissue create an environment where bacteria multiply rapidly and release sulphur compounds. Persistent bad breath is one of the more recognisable signs of gum disease that warrants a dental assessment.
- Tongue coating: A white or pale coating on the tongue is a build-up of bacteria, food debris, and dead cells. The back of the tongue is a particularly common site for odour-causing bacteria.
- Dry mouth: Saliva helps wash away bacteria and food particles. When the mouth produces less saliva, that cleansing effect is reduced and bacteria can accumulate more readily.
- Tooth decay: Cavities provide spaces where bacteria collect and produce odour. Untreated decay can worsen the problem over time.
- Certain foods: Strongly flavoured foods such as garlic and onions are digested, absorbed into the bloodstream, and eventually released through the lungs, contributing to temporary mouth odour.
- Tobacco use: Tobacco products affect the balance of bacteria in the mouth, reduce saliva production, and are associated with an increased risk of gum disease.
What Can You Do About Bad Breath?
Good oral hygiene is the foundation for managing most bad breath causes. Practical steps that may help include: 
- Brushing teeth twice daily with fluoride toothpaste, paying attention to all surfaces
- Cleaning between teeth daily with dental floss or interdental brushes to remove food particles from areas a toothbrush cannot reach
- Cleaning your tongue regularly with a tongue scraper or the cleaner on the back of your toothbrush
- Drinking enough water throughout the day to support saliva production
- Chewing sugar-free gum to stimulate saliva flow between meals
- Attending regular dental check-ups so your dentist can monitor for tooth decay, gum disease, and other factors that may be contributing
Mouthwashes can provide temporary relief but will not resolve an underlying cause such as gum disease or tooth decay.
A Considered Approach to Bad Breath at MyHM Dentist
Bad breath has a range of causes, and identifying the right one for your situation is the most important step. For most people, the answer lies in the mouth, and a thorough dental examination is the clearest way to find it.
At our clinic, Dr Hiromi Matsuoka takes time with each patient to understand what might be driving the problem, explain her findings clearly, and discuss what options may be appropriate. If you have noticed persistent bad breath and would like to arrange an assessment, we welcome you to get in touch.
Contact us today on (02) 9158 6379
Frequently Asked Questions
Is morning breath normal?
Morning breath is a normal occurrence and is not considered halitosis in the clinical sense. During sleep, saliva production slows significantly, which allows bacteria to multiply and produce odour-causing compounds overnight. It typically clears after brushing, drinking water, and eating breakfast. If a noticeable odour persists well into the day despite cleaning your teeth, it may be worth raising with your dentist.
Does mouthwash get rid of bad breath?
Mouthwash can reduce the number of bacteria in the mouth temporarily and mask odour for a short period. It does not address underlying causes such as gum disease, tooth decay, or tongue coating. For persistent bad breath, mouthwash is best used as part of a broader oral hygiene routine rather than as a standalone solution. Your dentist can advise on whether an antiseptic mouthwash may be appropriate for your situation.
References
Healthdirect Australia. (2026). ‘Halitosis (bad breath)’. Healthdirect Australia, 29 June. Sydney, NSW: Healthdirect Australia. https://www.healthdirect.gov.au/halitosis
Department of Health and Human Services. (n.d.). ‘Halitosis or bad breath’. Better Health Channel. Melbourne, VIC: Victorian Government Department of Health. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/halitosis-or-bad-breath
Australian Dental Association. (n.d.). ‘Should I clean my tongue?’. Teeth.org.au. Sydney, NSW: Australian Dental Association. https://teeth.org.au/tongue-cleaning
