Horizontal root fracture in posterior teeth without dental trauma: A diseased condition with special characteristics

Horizontal root fractures (HRF) were observed mostly in the anterior teeth of young adults due to dental injury. However, HRFs in posterior teeth (PHRF) without dental trauma cannot be neglected. The etiology and risk factors of PHRF were unclear. Lower premolars and palatal root of maxillary molars were particularly affected, indicating the specificity of this diseased entity. PHRF were mainly reported in Asian population, suggesting possible racial difference. Whereas most PHRF teeth showed symptoms mimicking endodontic and periodontal lesions, some affected teeth were asymptomatic. Periodontal pocket, soft tissue swelling, chronic pain or discomfort during mastication were commonly noted. Diagnosis of PHRF depended on thorough clinical examination, radiographic images or exploratory surgery. Intracanal bleeding and electronic apex locator confirmation during endodontic treatment were also useful for diagnosis. Flexible splinting, endodontic/periodontal treatment or root amputation were treatment strategies to preserve the fractured teeth. The aim of this narrative review is to summarize the demography, tooth and root distribution, diagnostic methods, etiology and possible related factors, clinical features, radiographic characteristics, and the treatment schemes of PHRF without dental trauma. A better understanding and identification of this particular root fracture could be achieved. The diagnostic tools and practical management are useful for clinical guides.