There are more reasons for dead pulp teeth, mainly including the following reasons: 1, tooth decay, decayed tissues slowly invade to the tooth tissue after causing pulp infection; 2, hidden fracture, due to like to chew hard things, bite bone, resulting in very small hidden fracture above the tooth, hidden fracture with the development of time more and more deep, causing pulp infection; 3, periodontal disease or periodontitis, periodontitis through periodontal tissue infection, retrograde infection to the pulp, may also cause pulp necrosis; 4, dental trauma, tooth fracture, wear and tear, night grinding and other reasons.