post during placement or during normal function. The ferrule can also help preserve the hermetic seal of the luting cement. It has been suggested that protection acquired by the use of a ferrule occurs due to the ferrule resisting functional lever forces, wedging effect of tapered posts and lateral forces during post insertion. To make full use of the ferrule effect, the preparation needs to allow for a continuous band of dentine which should be at least 2 mm in height from the level of the preparation margin and with the band being at least 1 mm in thickness. It has been shown, however, that whilst the absence of a 360° ferrule can increase the risk of fracture of root-filled teeth restored with fiber post and cores and crowns, having insufficient coronal walls poses an even greater one. Stainless steel crowns for posterior primary dentition Stainless steel preformed metal crowns are the treatment of choice for the restoration of posterior primary teeth. A systemic review found that it has the highest success rate (96.1%). In order to accept a stainless steel crown, the entire occlusal surface should be reduced by 1–1.5 mm and interproximally contacts should be cleared by cutting a thin mesial and distal portion or slice subgingivally by holding the tip of a thin high-speed bur at 15–20° relative to the long axis of the tooth, to avoid the creation of a shoulder. No preparation of the buccal or lingual/palatal surfaces is required. Stainless steel crowns can be made esthetic by veneering composite using the open face technique or composite veneering done after sand-blasting SSCs. Also, composite veneering can be done after preparing retentive grooves on the buccal surface of stainless steel crowns. Hall technique The Hall technique is a non-invasive treatment for decayed posterior primary teeth where caries are sealed under a preformed stainless steel crown. This technique requires no tooth preparation. Construction and fit of temporary crown restorations It is very likely that once a tooth has been prepared and whilst waiting for the definitive restoration, the tooth preparation is fitted with a temporary crown. Need for temporary restorations Temporisation is important after tooth preparation in order to: Protect from and prevent bacterial invasion of newly exposed dentinal tubules, leading to pulpal inflammation and necrosis; Prevent gingival growth in the area created by the tooth preparation; Allow area to be cleaned more effectively, decreasing the incidence