This study intend to study the development and introduction of new efficient approaches to overcome the problems of technique sensitivity of deep margin elevation by conventional flowable composite. This new class of Self- adhesive composites that have been developed and were marketed as flowable, low viscosity resin composites does not require any etching or bonding strategy before cavity filling and the ability to wet and adapt easily.The procedure is simplified by eliminating the adhesive application, which is the most technique sensitive step. (Fu J, Kakuda S, Pan F, e t al. 2013).

DME addresses multiple clinical problems associated with sub-gingival margins which pose a challenge due to limited access, rubber dam slippage over the margin and subsequent persistent saliva,

crevice fluid and blood leakage. There are uncertainties within the profession in providing DME, and it is still considered a new approach. A recent survey revealed 78% of dentists had more than one concern about the procedure, ranging from isolation and inspection, marginal adaptation, microleakage. (Taylor, Burns, 2024) FIT SA™, a new comprehensive self-adhesive flowable restorative with bioactive Giomer Technology inside. FIT SA has eliminated the need for the technique sensitive bonding procedure. FIT SA offers superior strength and polishability, and the unique filler structure combines the light transmission and diffusion properties of enamel and dentin to blend well withthe surrounding dentition.

Deep margin elevation (DME), or coronal margin relocation (CMR), is a procedure used to raise or reposition sub-gingival margins into supra-gingival margins using several materials to increase marginal integrity and bonding strength. Dietschi and Spreafico proposed the DME technique in 1998 to solve the problems associated with sub-gingival restorations. Despite this fact, it is still considered a new approach. Nowadays, clinical dentistry is directed toward conservatism, where in several situations the minimally invasive DME can replace the invasive procedures of crown lengthening. Sub-gingival preparations present difficulties that may complicate all further steps, such as rubber dam isolation, impression taking both digitally and traditionally, placement of a restoration, cementation as well as cervical area finishing and polishing. Moreover, indirect partial posterior restorations often display sub- gingival margins, which are accompanied by both biological and operative problems. Operative problems are attributed to changes in the tooth structure that are associated with deep margins, such as the absence of enamel, where dentin and cementum will pose more difficulties in bonding. Up until now, there is a limitation in the studies assessing the advantages and limitations of DME, most of them are in vitro concentrating on fracture resistance, bond strength, and marginal adaptation of indirect restorations. (Aldakheel, Almuhtab et al.2022).

Inclusion Criteria:

Patients accept the one year follow up period. Cooperative patients. The study recruited volunteers of both genders Age from 21 to 45 years Primary compound proximal caries, with International Caries Detection and Assessment System (ICDAS) scores of 4 or 5.

The buccolingual width of the lesion could not exceed two-thirds of the intercuspal distance.

The remaining dentin thickness not less than 1 mm from the pulp and that could be identified clinically and by periapical xray Vital teeth without any signs of radiolucency in the periapical or furcation areas.

Participants also had to present a moderate risk of caries.

Exclusion Criteria:

Those who requiring any form of pulp capping will excluded to differentiate postoperative hypersensitivity from pulpal inflammation.

Individuals with poor oral hygiene. Patients undergoing orthodontic treatment. Periodontal surgery patients. Smokers. Pregnant women. Patients without occlusal contact. Those suffering prolonged tooth pain that disrupted sleep.