Patients who are undergoing chemotherapy and those who are recovering from chemotherapy frequently present with sensitivity of the dentition. This is due to the cytotoxicity of the drugs, which affects primarily the periodontal tissues and in some rare cases, the dental pulp. Nausea and vomiting is also a frequent side effect of chemotherapy and patients are thus prone to dental erosion from the acidity of the gastric contents. Dental erosion can cause teeth sensitivity and aesthetics issues if the front teeth are involved.
Teeth sensitivity is tricky to manage; patients may avoid brushing the sensitive cervical zones of the dentition (necks of the teeth at the gum line) due to sensitivity. This predisposes them to a vicious cycle involving accumulation of dental plaque and calculi around the cervical margins of teeth causing an inflammatory response of the gums which will lead to periodontal disease and the sequalae of gingival recession and further sensitivity. To complicate matters, salivary gland dysfunction associated with the cytotoxic effects of chemotherapy sometimes results in qualitative and quantitative changes in saliva. This predisposes the patient to dental caries, typically along the cervical margins (junction between the crowns and the roots of teeth) where the patients feel more sensitive to start with. This will also aggravate the symptoms of teeth sensitivity.
Therefore, it is very important for patients to make a dental visit prior to chemotherapy and to continue with oral care throughout chemotherapy. During the dental visit, the dental practitioner will perform the necessary dental treatment required so as to reduce the chance of acute dental events during chemotherapy. In addition, areas requiring more attention will be made known to the patients so that they can improve on the preventive daily care over the vulnerable regions.
Toothbrushing can still be possible in most cases with the use of toothbrushes with ultra-soft bristles if the affected patient cannot tolerate brushing with their usual toothbrushes due to severe sensitivity of the periodontal tissues and the teeth. Flossing and interproximal cleaning aid remains crucial in the prevention regime and should be continued where possible.
In the event the patients totally cannot tolerate any toothbrushes, an oral swab may be used as an alternative but it is a poor substitute and patients should be switched back to using a toothbrush as soon as possible. Chlorhexidine-containing mouthrinses can also be used as an adjunct but it is best to use the alcohol-free versions as the alcohol content tends to desiccate the oral soft tissues and aggregate the sensation of sensitivity. Moreover, it is important to inform the patient of chlorhexidine-induced teeth staining especially if usage extends beyond one week. These stains can be removed easily during dental polishing later on when patient is able to tolerate dental procedures.
Toothpastes with foaming agent, namely sodium lauryl sulphate (SLS), sometimes irritate the soft tissues during chemotherapy and this sensitivity does extend beyond completion of chemotherapy. Similarly, patients may become more sensitive to the flavouring in the toothpaste during and after chemotherapy. In such cases, toothpaste formulas with milder flavouring or SLS-free, may be used but it is important to use those containing fluoride. Sometimes, patients may also switch temporarily to fluoridated toothpastes designed for children. The minimum recommended fluoride concentration in toothpaste for effective caries prevention is 1000ppm.
When chemotherapy triggers nausea and vomiting, patients should be advised to rinse the mouth well after each episode to reduce intraoral acidity. Affected patients may apply a thin smear of toothpaste with desensitising formula on the areas on the dentition sensitised by the gastric acid and to rinse off after 15 minutes.
Patients with concurrent issue of dry mouth during and after chemotherapy may find it useful to have a gargle with water to wet the intraoral soft tissues first, then use an oral lubricant/moisturising product for sustained relief. Similarly, it is good practice to encourage patients to wet their lips first before applying a thin smear of oral moisturiser for sustained relief.
It is important to note that teeth sensitivity may be associated with crack-lines or defective restorations on the affected teeth. Therefore, patients are encouraged to visit the dentist for assessment. In the dental practice, desensitising agents may be applied on the offending exposed dentinal surfaces and defective restorations will be replaced if necessary. In cases where the teeth with crack-lines are symptomatic, root canal therapy and/or crown placement may be required, depending on the vitality of the pulp and the status of the remaining tooth structure.
Dr Tay Chong Meng
Consultant
Division of Prosthodontics
National University Centre for Oral Health, Singapore (NUCOHS)
Dr Tay Chong Meng obtained a basic dental degree in National University of Singapore (NUS) and has been awarded the Geriatric and Special Needs Dentistry Scholarship by Ministry of Health to pursue further studies in this field. He has completed his clinical postgraduate degree in Melbourne in 2011 and is currently working as a dental consultant in the University Dental Cluster. He specialises in the management of patients with disabilities as well as those with complex medical issues. He holds an adjunct position in Faculty of Dentistry NUS as an educator and is seconded to MOH to assist in dentistry related matters in Chief Dental Officer's Office under the Part-time Professional Scheme.