Tooth Sensitivity

Tooth sensitivity (dentine hypersensitivity) is a short, sharp pain arising from exposed dentine in response to thermal, evaporative, tactile, osmotic or chemical stimuli, which cannot be attributed to any other dental defect or disease. Dentine becomes exposed when enamel or cementum is lost or when the gum recedes, and open dentinal tubules transmit fluid movement to the pulpal nerves (the hydrodynamic mechanism).

• Prevalence is 10 to 30 percent in adults and higher (up to 60 to 70 percent) in people with periodontal disease; peak age 20 to 50 years; the buccal surfaces of canines and premolars are the commonest sites.
• Causes of dentine exposure: gingival recession (over vigorous brushing, periodontal disease, periodontal treatment, orthodontics), enamel wear by erosion (acidic food, drinks, reflux, vomiting), abrasion, attrition (bruxism), abfraction (cervical lesions from flexion), tooth bleaching, and tooth fracture.
• Other conditions causing similar pain need to be excluded because the treatment differs: caries, cracked tooth, leaking or high restorations, pulpitis, gingival or periodontal disease, post-restoration sensitivity.

• Sharp pain lasting seconds (under 30 seconds) after cold air, cold drinks, hot drinks, sweet or sour foods, brushing, or touch; stops when the stimulus is removed.
• Localised to one or more teeth, often in the neck of the tooth at the gum line; worse in cold weather and after acidic foods.
• No spontaneous pain and no lingering pain beyond a minute (those features suggest pulpitis).
• Examination: recession, cervical wear lesions, exposed roots, worn occlusal surfaces, erosion, plaque, and restoration margins.
• Patients avoid brushing the sensitive area, causing plaque build up and gingivitis.

• Diagnosis by exclusion based on history and examination.
• Tactile test with a dental probe along the cervical area, and evaporative test with a 1-second air blast from a dental syringe at a distance of 1 cm; rate pain on a visual analogue scale (0 to 10) or a verbal scale.
• Test adjacent teeth with the same stimulus to find the affected tooth; use cold test (ice stick) and percussion to exclude pulpitis or apical disease.
• Radiographs (bitewing and periapical) to exclude caries, defective restorations and periapical disease.
• Assess diet (acidic food and drink frequency), reflux, vomiting, bruxism, brushing technique, bleaching, and recent dental treatment.
• Differentials: dental caries, cracked tooth, pulpitis (reversible or irreversible), failing restoration, post-bleaching sensitivity, periodontal abscess, sinusitis (upper molar pain), trigeminal neuralgia, and temporomandibular disorder.

Explain and remove causes

• Brush twice daily with a soft brush and light pressure (a pressure sensitive electric toothbrush helps), using a gentle technique rather than horizontal scrubbing.
• Reduce acid exposure: restrict acidic foods and drinks (citrus, fruit juices, carbonated and sports drinks, wine, vinegar) to mealtimes, use a straw, rinse with water or milk afterwards, and wait at least 60 minutes before brushing.
• Treat gastro oesophageal reflux (omeprazole 20 mg daily for 4 to 8 weeks) and eating disorders.
• Avoid whitening products with high peroxide concentration while symptomatic; use a night guard (hard acrylic) for bruxism.

Home desensitising agents (first step)

• Desensitising toothpaste twice daily for at least 4 weeks (full benefit takes 2 to 4 weeks), brushing for 2 minutes and spitting out without rinsing:
  • Potassium nitrate 5 percent (nerve desensitisation), or
  • Stannous fluoride 0.454 percent (occludes tubules), or
  • Arginine 8 percent with calcium carbonate, or
  • Bioactive glass (calcium sodium phosphosilicate) 5 percent, or hydroxyapatite.
• Apply a small amount of the toothpaste directly on the sensitive area with a finger before bed and do not rinse, to increase contact time.
• Fluoride mouthwash 0.05 percent sodium fluoride daily or 0.2 percent weekly; high fluoride toothpaste (5000 ppm) by dental prescription.

Professional treatment (if no relief after 4 to 6 weeks)

• Fluoride varnish 22,600 ppm applied to the affected areas every 3 to 6 months; glass ionomer or resin modified glass ionomer restorations or sealants for cervical lesions; dentine bonding agents; potassium oxalate; laser therapy (Nd:YAG or Er:YAG).
• Gingival graft for severe recession with root exposure; treat periodontal disease; adjust occlusion if there is traumatic occlusion.

Escalation

• Refer to a dentist if pain lasts more than a few weeks despite treatment, is spontaneous, lingers for more than 30 seconds after the stimulus, wakes the patient at night, or is accompanied by swelling (suggesting pulpitis or abscess, which need endodontic care).
• Analgesia for short term flare ups: ibuprofen 400 mg or paracetamol 1 g.

Follow up

• Review after 4 weeks; if controlled, continue desensitising toothpaste long term and attend regular dental checks every 6 to 12 months.