Evaluation of Bioflex Crowns Endocrowns Compared to Ready-Made Zirconia Crowns on Pulpotomized Primary Molars

This study will be conducted to evaluate clinical performance, parent's satisfaction, gingival health and bacterial effects of Bioflex crowns \&Endocrowns compared to ready-made zirconia Crowns on Pulpotomized primary molars

Intervention: Pulptomy Procedures The tooth will be anaesthetized. Then, it will be isolated using a rubber dam. Caries will be removed with a sterile non-end cutting bur # 558 to complete the removal of the pulp chamber roof under copious water coolant spray. Coronal pulp tissue remnants will be removed with a sharp, sterile excavator. A piece of cotton soaked with formocresol will be inserted into the pulp chamber for 5 minutes. After removing the formocresol pellet, a thick mix of zinc- oxide/eugenol paste will be packed into the pulp chamber to seal the oriﬁces.

Restoration of the tooth:

According to the groups restoration will be as the following:

Group A: Endocrowns tooth preparation, scanning, cementation:

For the endocrowns A layer of light -cured glass ionomer cement ° of 1 mm thickness will be applied over the ZOE- to isolate it from the successive resin based restorations and adhesives- leaving a minimum of 3 mm of the pulp chamber to provide an adequate thickness for the endocrown core.

Round-end tapered stone will be used to achieve depth cuts of 1.5 mm for occlusal clearance A wheel stone will complete the occlusal reduction and making butt joint ﬁnish line.

Tapered stone of 8-degree angle will be used to prepare axial wall ﬂared, the pulp chamber walls to a standard degree of divergence.

Abrasive rubber tip will be used to smoothening and rounding the internal angles giving a polished and smoothed preparation.

Endocrown will be manufactured using CAD/CAM technology internal wall of crown will be treated with etchant material, rinsed, dried then silane coupling agent Dual-cure resin cement will be applied on the crown fitting surface for endocrown cementation. Group B: Preformed Bioflex crowns

According to manufacturer instruction the preparation will be as the follow:

Light -cured glass ionomer filling of adequate thickness will be applied over the ZOE to seal the cavity before preparation A digital caliper will be used to measure a mesio-distal dimension of tooth then suitable sized preformed crown will be selected.

Tooth preparation will be carried out with a tapered diamond bur for occlusal reduction by 1-1.5 mm, including the central groove.

The proximal preparation will be around 0.5 mm to clear the contact area Placement of the crown will be achieved by a snug fit followed by contouring using a Hover's plier.

Crown cementation will be carried out using glass ionomer cement and removal of excess cement using floss or explorer.

Group C: performed zirconia crowns Light -cured glass ionomer filling of adequate thickness will be applied over the ZOE to seal the cavity before preparation.

A digital caliper will be used to measure a mesio-distal dimension of tooth then suitable sized preformed crown will be selected.

A diamond bur will reduce the occlusal surface by 1.5-2 mm Interproximal contacts will be prepared with a tapered fissure bur. About 1-2 mm sub gingival preparation will be performed The selected crown will be placed and checked. The passive fit of the crown will be assessed and will be luted with glass ionomer cement.

Consistent firm finger pressure will be applied during cementation. Observations:

Clinical Performance Assessment Retention, marginal adaption, fracture of the restoration were scored using a modified United States Public Health Service (USPHS) criterion.

Dental plaque accumulation and gingival condition were assessed using plaque index (PI) and GI.

Preparation time and cementation assessment using stop watch to record time from preparation start till final restoration cementation.

Clinical performance and oral status will be assessed at follow-up periods of 3 (T1), 6 (T2), and 12 (T3) months. At the end of the follow-up (T3), parent's satisfaction analysis toward the color, shape, and size of three restorations will be adopted to directly evaluate their satisfaction toward their children's restorations. Parents' responses were rated on a 5-point Likert-type scale.Microbiological analysis:

The swabs will be collected before preparation of crowns, 3 months, 6 months and 12 months after cementation. The number of Streptococcus Mutans, lactobacillus will be digitally counted. Swabs will be taken from occlusal surface by means of the tips of sterile cotton The number of Streptococcus Mutans, lactobacillus will be digitally counted. Swabs will be taken from occlusal surface by means of the tips of sterile cotton Samples will be preserved in a transporting medium tube containing 9ml thioglycolate broth medium. All specimens were transported immediately to microbiological lab.

Eligibility Criteria:
Inclusion Criteria:

1 - Parents' and patients' acceptance and cooperation 2- Apparently Healthy children. 3- Child's age ranging from 4 to 8 years old. 4- Primary 2nd molars with deep carious lesion indicated for vital Pulptomy 5- No periapical pathological lesion 6- No root resorption exceeding more than 2/3 of root length.

Exclusion Criteria:

1. Medically compromised children (bleeding disorders, cardiac patient and any systemic diseases could affect oral and gingival health.
2. Presence of para-functional habits. Such bruxism, TMJ disorders
3. Non-restorable tooth.
4. Teeth with non-vital pulp