-Background: A crown-root fracture is defined as a fracture involving enamel, dentin, and cementum. The possibility of saving and reconstructing teeth with such fractures has increasingly become a viable alternative to extraction and prosthetic therapy. One such treatment option available is surgical extrusion. Objective: The aim of this review is to evaluate surgical extrusion as a treatment modality for management of crownroot fractures in permanent anterior teeth. Methods: Electronic search of scientific papers was carried out on Entrez Pubmed and the Cochrane Central Register of Controlled Trials databases using specific keywords. The search yielded 130 papers, out of which 16 relevant papers were identified and included based on predetermined inclusion criteria and the remaining 114 were found to be irrelevant. Hand search yielded 10 articles, which were also included. These 26 articles which included only case reports and case series formed the basis of this systematic review. Conclusion: From the existing literature, we can conclude that surgical extrusion can be used to treat crown-root fractures successfully. But the level of evidence is very low as the studies available are only case reports and case series.

Previous studies have reported a high incidence of hemoglobin E (HbE) in Northeast Indian populations. In the present study 10 endogamous populations of Assam belonging to two racial groups, Caucasoid and Mongoloid, were examined. The frequency of HbE gene (Hb βE) in the Caucasoid caste populations is around 0.1, whereas the gene is highly prevalent in the Mongoloid populations, frequencies ranging between 0.2 and 0.6. Predominance of Hb βE in the Tibeto-Burman speakers is contrary to observations made in Southeast Asia, where an association between Austro-Asiatic speakers and high prevalence of HbE exist. The highest occurrence of the gene in this area, which is on the far end of the proposed centre of distribution in Northern Kampuchea and Northeast Thailand, is also a deviation from the expected pattern of gene distribution. It is speculated that Hb βE in the Tibeto-Burman populations of Assam arose by an independent mutation which contributed to the high frequencies of Hb βE in the Northeast Indian populations.

The distribution of the hemoglobin Constant Spring (Hb CS) gene in eight populations in Southeast Asia (including Assam) was determined using oligonucleotide hybridization. Hb CS was absent in two Assamese populations with a high prevalence of Hb E. The Hb CS gene frequency was 0.033 in northern Thailand and near 0.01 in central Thailand and Cambodia. High frequencies, between 0.05 and 0.06, were observed in northeastern Thailand. The present data and a similar study in Laotians suggest that the Lao-speaking populations of the Mekong River basin in northeastern Thailand and Laos have the highest frequencies of the Hb CS gene in Southeast Asia.

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