Does a missed diagnosis or failure of dental treatment constitute negligence?

Negligence means failure to employ the required care and skill which caused patient injury.
But incorrect diagnosis does not necessarily constitute negligence. Because of the many judgements involved in dental practice it is considered unrealistic to expect that a dentist be 100% correct. The patient must demonstrate serious injury because of the dentist's failure to diagnose properly before there are grounds for negligence. Furthermore, it must be shown that the dentist failed to exercise the applicable standard of care. But injury alone is grounds to file a suit for negligence.
If the overcome of treatment is bad for example endodontic treatment due. to a separated instrument, then negligence is not necessarily supported if the appropriate standard of treatment is employed. However, if a dentist promises to effect a specific cure, to bring about a particular results, or to complete a procedure with no residual problems and fails to fulfill the promise, a lawsuit may be filled on the basis of breach of contract rather than negligence.