October 24, 2018
The term ‘hot tooth’ in dentistry represents a condition of inflamed tooth pulp. This can be due to extensive tooth decay, periodontal (gum disease) complications or leaking old filling. The actual diagnosis is irreversible pulpitis, leading to spontaneous severe or moderate pain. It is an emergency situation, most commonly described as a patient, who is sitting in the waiting room, sipping on a bottle of ice-cold water to help relieve the pain.
The hot tooth syndrome appears when the chronic inflammation of the pulp progresses into an acute exacerbation (flare up). During this acute pulp inflammation, the blood vessels increase their permeability which allows the plasma proteins to escape the blood and get into the connective tissue spaces outside the capillaries (the smallest blood vessels that occupy the tooth pulp chamber). This results in edema and increased pressure on the nerve fibres, which react with symptoms like discomfort and pain. The pressure into the pulp chamber can increase an average of 15mm Hg in the local area of inflammation. When a cold stimulus is applied (sipping on cold water or applying an ice pack) the blood vessels constrict and the intrapulpal pressure decreases. The effect is more visible if the tooth has an amalgam (silver) or gold restoration, because the metals are good thermal conductors. The hydrodynamic movement of fluids is the best explanation for the immediate relief of symptoms after applying cold to the hot tooth – blood vessels constriction and decreasing intrapulpal pressure.
How to numb up a hot tooth
1. Patient can be premedicated with non-steroid anti-inflammatory drugs like 800 mg Ibuprofen or 1000 mg Paracetamol with a glass of water, 30 min prior to local anaesthesia. This is done to suppress inflammation
2. Dentist should not bury needles to the hub in soft tissue
3. Dentist should not use 30G needles
4. Local anaesthetic Lignocaine (1:80000 epinephrine) should be administered initially as an ID block. Wait for 5min and then administer ½ cartridge as Gow Gates technique (Scandonest 3% plain) 1cm higher than the stnadard technique. Don’t contact the bone and don’t forget to aspirate. You can double aspirate by rolling the needle through 90 degrees. Positive aspiration is rare
5. Exposing longer section of nerve to the local anaesthetic is likely to produce higher degree of success
6. The numb lip scenario, a +ve lip sign indicates local anaesthetic efficacy with A delta fibres. However, this does not indicate pulpal anaesthesia
7. Long buccal infiltration, 0.5 ml of articaine
8. You can use an electric pulp tester to assess efficacy
9. Quoted success rate for pulpal anaesthesia with pulpitis cases is 25% success rate and 75% failure
10. You can use alternative local anaesthetics to modify the pH of the local tissues (this will improve the permeability of the anaesthetic into the bone)
11. You can do lingual infiltration, to block the Mylohyoid nerve sensory branches. They tend to innervate the mesial roots of the lower molars. The technique here is, to deposit 0.5 ml in the attached gingivae lingual to the tooth distal to the one you are working on
12. Intraligamentary infiltration of the anaesthetic may be used but this creates post operative discomfort for the patient
13. Dentists can use an electronic device for controlling the rate of infusion. A computerized local anaesthetic system, known as WAND, has been developed to automatically deliver LA solution with a fixed pressure. This potentially results in controlled, comfortable and highly effective injection into resilient tissues like the palatal and periodontal mucosa. However, this can be used effectively by hand, because a WAND device costs around $1500
14. If the tooth is still sensitive as you are drilling out the dentine it can be dressed with Ledermix or Pulpomixine
15. If the pulp is directly exposed, but very sensitive, the tooth can be dressed with Ledermix or Pulpomixine
16. If the pulp is directly exposed, but very sensitive, you can do intrapulpal anaesthesia. It s creates a sharp pain to the patient so make sure you prewarn about the discomfort. It is very effective as long as you are able to develop pressure with the injection. It should provide about 10 min of analgesia – lond enough to do the pulpectomy and remove the nerve. All anaesthetics are effective in the intrapulpal injections
17. Alternative techniques to be used on a hot tooth are intra-osseous LA infiltration, stabident and X-Tip (Prestige dental)
18. Scandonest can be used as an alternative anaesthetic
19. Another anaesthetic useful for controlling hot tooth pain is Bupivacaine (Marcaine)