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Agenesis of lower second premolars in an uncrowded dentition can represent a significant clinical challenge. Leaving the second primary molars and ultimate prosthetic replacement places a dental and financial burden on the patient. Therefore, space closure while often the preferred option, can be very difficult while controlling the overbite and position of the lower labial segment. Also loss of alveolar bone may make this impossible. Hemisection of the lower second primary molar can facilitate space closure by maintaining bone and if done at the correct time, allow the first molar to move mesially resulting in spontaneous space closure. This article describes this technique and illustrates it clinically.
CPD/Clinical relevance Hypodontia of the lower second premolars is a common problem and space closure to negate the need for expensive prosthodontics can be challenging. Hemisection of the second primary molar is a relatively simple procedure that can make space closure more predictable.
Lower second premolars have been reported to be the most common missing teeth after third molars in non-syndromic hypodontia.1 In an uncrowded dentition, their absence represents a specific clinical challenge: the decision of whether to try and maintain the second primary molar, or whether to extract it and either prosthetically replace the missing second premolar, or attempt space closure. While each of these options has pros and cons, which are beyond the scope of this article, if successful, space closure will significantly reduce the dental burden created by placement of a resin-retained bridge or implant on the patient. However, controlled closure of the 9–10 mm of space created by extraction of a lower second primary molar, in an otherwise uncrowded dentition typically found in these patients, can be clinically challenging. Therefore, the purpose of this article is to demonstrate how space closure can be helped with the use of the simple and elegant technique, hemisection.
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