Deep Marginal Acquisition With Thermacut Bur Versus Functional Crown Lengthening in Management of Deep Subgingival Interproximal Carious Lesions: A One Year Follow-up Randomized Controlled Trial

Deep subgingival margins pose a great difficulty during restorative work with composite restorations. Exposing cavity margins is paramount in order to attain proper isolation, matrix adaptation and composite placement.

Several methods have been proposed to overcome the problem of exposing deep margins; functional crown lengthening is considered the gold standard of care regarding exposure of deep margins.

However, functional crown lengthening can pose many problems including the risk of root exposure, furcation involvement and compromising crown root ratio, besides risk of thread exposure if it is done beside implant, removal of bone from adjacent teeth and from buccal and lingual walls in order to create smooth bone architecture, and the complications of surgery such as post-operative pain, inflammation and edema and the risk of excessive bleeding.

Deep marginal acquisition and deep marginal extension (DMA & DME) are considered as a viable option in treating deep subgingival extended margins.

Several methods regarding deep marginal acquisition have been proposed including the use of diode laser and Electrosurgery, there is another protocol for exposing the gingival seat by the use of thermacut bur.