Tooth hypersensitivity is characterized by a transient short and sharp pain originating from exposed dentin in response to thermal, dehydrating, tactile, osmotic, and chemical stimuli. Tooth sensitivity after cementation of complete coverage crowns, is a rather common event since much of the protecting enamel is removed during preparation and a large area of dentin is exposed.

Dentin contains up to two million tubules per cm2, which corresponds approximately to the surface area of most crown preparations. It is well known that such dentin wounds respond to mechanical, osmotic, or thermal stimulation with pain. This phenomenon is commonly example by the hydrodynamic theory of Brannstrom.

The extent and duration of post cementation hypersensitivity has been related to number of factors, mainly associated with preparation trauma. However, research reports confirm potential effects of luting agents used and leakage of bacteria and bacterial products from the oral cavity along the margins of restorations, especially as a response to poorly fitting temporary restorations. Apparently, a relationship exists between the time interval during which the temporary restoration is in place and post cementation sensitivity.

Gluma Desensitizer is a combination of glutaraldehyde and HEMA (Hydroxy Ethyl Methacrylate). Glutaraldehyde causes amino acids and proteins to coagulate in dentinal tubules and is an effective disinfectant. HEMA can be effective in sealing of dentinal tubules.

Gluma does not interfere with dentin bonding systems but its glutaraldehyde component can damage the gingiva after long term exposure. HEMA can cause contact dermatitis and it can actually perforate latex gloves and must be used with caution, hence, the use of rubber dam is advised in such cases .

HEMA is soluble in water allowing it to penetrate deep into dentinal tubules however, the effect is reversible and HEMA gradually loses its effect allowing the dentinal tubules to again became exposed.

Hydroxyapatite powder is one such material that exhibits excellent bioactive properties and striking similarities to dental hard tissues can be achieved from two different sources. Synthetic and natural (biologic) hydroxyapatite.HAP can be produced from Coral Seashells, eggshells and also from body fluids.

Recently, the use of waste materials to synthesize HAP has received great response from many researchers across the world. This idea gives an innovation to produce a new valuable product from the waste materials such as seashell.Seashell consists of high source of calcium that can act as calcium precursor. Some researcher found that the content of calcium carbonate (CaCO3) in seashell is approximately between 98 and 99 %.

The word seashell is often used to mean only the shell of a marine mollusk. Using seashell as source of calcium carbonate (CaCO3) to produce calcite nanoparticle is meaningful for both environmental protection and biomedical application. Seashell is with the natural ceramic structure are similar to human bone and tooth structure.

The conversation of macroparticles into nanoparticles resulted in larger surface area increasing the reactivity of nanoparticles and hence, it's efficacy. Nanoparticles have widespread use due to their superior properties and are being investigated extensively in recent years due to their advantages.Nano -sized materials can enter dentinal tubules of 2 -3 µm in diameter, easily occluding the dentinal tubules

Inclusion Criteria:

• For patient Age between 25 and 40 years and no gender reference.
• For the teeth Absence of pulpal exposure, RCT treatments, fracture and free of extensive caries (The amount of caries that can be removed during the preparation is acceptable

Exclusion Criteria:

• -For patients Use of desensitizing substances or drug like antihistamines, antidepressant 6 weeks before or during the study.

Requiring antibiotic prophylaxes or cortico-steriod therapy.

-For teeth Tooth hypersensitivity prior to tooth preparation (like, abrasion or attration).