The patient had been attending the DDU dentist's practice for a number of years for routine dental treatment under local analgesia without any problem, including crowns on all his upper incisors following an accident.

The patient had become conscious of the appearance of two upper canines, which were a different colour from the crowns and were progressively beginning to discolour at the gum margins. He agreed to both these teeth being veneered to improve their appearance. The teeth were prepared under local analgesia at the following visit and impressions were taken to construct the veneers. On the following day, the patient noticed that the analgesia on the left side was still present, whilst on the right-hand side it had worn off as usual. Moreover, the left side of his face, where the injection had been given, was noticeably swollen, painful and tender to touch.

The patient consulted the dentist two days after the injections and was advised that there may have been some soft tissue damage caused by the local analgesia. Ibuprofen tablets were prescribed and the patient was reassured. The left side of the patient's face developed some mild bruising over the next few days, but this resolved spontaneously, though the numbness and swelling remained. The veneers were fitted uneventfully two weeks later and were satisfactory.

The facial swelling gradually reduced over the next six months and eventually resolved completely, although the patient still complained of mild pain when firmly pressing the cheek just below the left eye. The area of facial skin affected by the numbness also gradually reduced over 6 months, but did not completely resolve.

The patient reported that the affected area felt different (paraesthesia) from the remainder of his face. He also complained of a mild twitch in his left upper lip which developed after the injection. As there was no improvement in the symptoms, the dentist referred the patient to the oral surgery department of the local hospital. The senior house officer diagnosed direct trauma to the nerve during the administration of local analgesia and the patient was advised that sensation should improve, but recovery might not be complete. In view of the incomplete recovery of sensation, the patient was referred to a school of denistry.

Negligence alleged

During the patient's consultation at the school of dentistry, a note was made of "inadvertent infra-orbital nerve block", which was referred to later by the solicitors and expert acting for the patient. The patient's expert, a maxillofacial surgeon, maintained that during the administration of the local anaesthetic the infraorbital nerve had been contacted by the point of the needle and as a result the patient had suffered nerve damage. He concluded that the dentist was negligent as he was using a local anaesthetic technique which was unnecessary for the required treatment and that had an infiltration local anaesthetic been given there would not have been any neurological damage.

Outcome

The DDU's dento-legal adviser instructed a consultant in restorative dentistry, who concluded that "the evidence strongly suggests that, on the balance of probabilities, this injury was caused by pressure from a sub-periosteal haematoma rather than physical damage from the injection needle." He went on to add "It is generally agreed that the production of a haematoma during the injection of local analgesia is an unfortunate accident which could happen in the best of hands. There is therefore nothing to show that the practitioner's management of this case fell below the standard expected of a reasonably competent general practitioner."

Following receipt of the expert's report, the dentist maintained that he would never have given an infra-orbital block, even inadvertently, and confirmed that he wished to continue to defend the case. A review of the case estimated that should the case be lost, then damages would be awarded to the patient in the region of £7,500 to £10,000 plus their costs which could be in the region of £10,000 to £15,000.

A trial date was set and after two days of trial, the judge found in favour of the dentist and the case was dismissed.

After-effects from local analgesia

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