Clinical Performance of the Indirect Resin Composite Restorations in Endodontically Treated Teeth
Condition: Endodontically Treated Teeth
MeSH terms: Tooth, Nonvital
Study type: Interventional

Summary: 
      Does the cuspal reduction during cavity preparation for indirect resin composite restorations
      in endodontically treated teeth increase the clinical performance when compared to cavities
      prepared without cuspal reduction?
    

Detailed description: 
      Selection and examination of the all patients will be done according to inclusion and
      exclusion criteria( by Hoda omar fouda in the Faculty of Dentistry Cairo University, Egypt )
      from the outpatient clinic of the conservative department of the faculty of oral and dental
      medicine , cairo university .Patients should have an endodontically treated molar with
      remaining three walls fulfilling the inclusion criteria of the selected teeth or patients who
      need root canal treatment to be done prior to restoration to be enrolled in the study. Root
      canal treatment for all patients will be done by step back technique using rotary files
      .Sodium hypochlorite and EDTA solution will be used as root canal irrigant solution. Root
      canals will be obturated with gutta percha cones using AH Plus (Dentsply, Konstanz Germany).
      Eugenol based sealers will avoided to avoid the contamination of the remaining walls with
      eugenol that can interfere with the polymerization of the adhesive.

      Eugenol free temporary filling material (Coltosol F by Coltene, Switzerland) will be used to
      seal the cavity till the restorative visit A digital periapical radiograph will be done to
      check the quality of the root canal treatment. The selected tooth should be free from any
      periapical radiolucency, missed canals or poor obturation. The periodontal condition of the
      tooth will be also checked radiographically. The tooth should be free from any clinical
      symptoms as pain on biting or swelling. A period not more than a month should pass from the
      root canal treatment to avoid any coronal leakage that might affect the prognosis of the root
      canal treatment during the time of the study. Any defects in the temporary filling material
      should be restored again to assure proper coronal seal till the beginning of the treatment.
      Before the removal of the temporary filling, assessment of centric and eccentric occlusal
      contacts will be performed with an articulating paper. The tooth should be then checked for
      the contact points in the centric relation and eccentric movements It is important to
      determine the contact points during the centric and eccentric movements to maintain the tooth
      restoration interface at a stress free areas as much as possible for more durable bonding.
      The quadrant with the cavity will be isolated using rubber dam system with two suctions tips
      one below the rubber dam sheet and the other one near to the tooth to keep the working area
      always clean and keep the patient comfortable during the procedures. Using straight and round
      blue coded diamond stones attached to high speed handpiece with copious air and water
      coolant, the temporary filling will be removed from the cavity. The cavity should then be
      checked for any remaining carious lesions to be removed. All the undermined enamel walls
      should be removed so that all the remaining cavity walls have well supported sound enamel
      margins. Any soft carious lesions will be by a sharp spoon excavator. Any gutta-percha
      remnants in the pulp chamber should be removed till the gutta percha becomes at the level of
      the orifice and all the walls and floor are completely clean. All the procedures will be
      performed with magnifying loupes 3.5 x (Univet, Italy). The angulation of the cavity walls
      will be adjusted to be 6 degrees diverge of the axial inclination using blue coded diamond
      tapered with round end bur diameter 16, length 10.

      Standardization of the prepared cavity dimensions should be done as follows:

        1. For the inlay group thickness of remaining walls (in order to maintain them) has to be
           1.5 mm.

        2. The occlusal inter-cuspal distance ranges from 4-5 mm

      4- Width of occlusal isthmus had to be 2-3 mm. 5- Buccal and lingual walls of the proximal
      parts of the cavity will be prepared using the same diamond bur (MIDWEST Dentsply) used for
      the occlusal part of the cavity to provide the same angle of divergence (6 degrees) as that
      of the occlusal walls. 6- The proximal boxes corresponds to one-third the distance between
      the buccal and lingual surfaces of the teeth 7- The gingival floor of the proximal part of
      the cavity has to be continuous with the pulpal floor of the occlusal part having the same
      depth. 8- Interproximal overjet has to be ≤ 2 mm. 9- The internal line angles should be
      rounded, the cavo-surface angles should be 90° For the Intervention Group: no cuspal
      reduction will be done as these will be the cavities prepared to receive the inlay
      restorations For the Comparator Group: cuspal reduction to buccal and lingual cusps will be
      done as these will be the cavities prepared to receive the onlay restorations

      Acid etching:

      Selective etching technique using a 35% phosphoric acid gel (Scotchbond™ Universal Etchant
      3M) on the marginal enamel for 15 seconds. The gel will then thoroughly rinsed for about 30
      seconds using air water spray and then air dried for 5 seconds.

      Application of adhesive:

      After proper dryness and with the aid of a micro-brush (Microbrush International, USA), the
      Prime and Bond universal adhesive (Dentsply Sirona) will be applied over all the cavity
      surfaces according to the manufacturer's instructions and rubbed for 20 seconds then blown
      with a gentle air blow for 5 seconds to evaporate the solvent and then light cured for 10
      seconds using LED curing light (Elipar S10, 3M ESPE) at a light intensity of 1200 mw/cm2.

      Application of the base:

      Bulk fill flowable composite SDR (Dentsply sirona) of universal shade will be directly
      applied to the floor of the cavity to fill the pulp chamber from bottom to top and light
      cured for 10 seconds according to the manufacturer's instructions with the same light curing
      device as the adhesive.

      Milling of the designed restoration:

      The operator will adhere strictly to the manufacturer's instructions in the imaging, computer
      design and machining of the restorations. A CEREC Primescan unit with Operating System 1.21
      and the extended machining option for the milling process. BRILLIANT Crios Composite Blocks
      for CEREC® will be used to design and mill the inlays and onlays.

      Cementation protocol:

      The fitting surface of the restoration will be treated as follows to be ready for
      cementation:

        -  Sandblasting by AquaCare Air Abrasion Unit using aluminum oxide particles of 0.5 mm
           particle size.

        -  Ultrasonic cleaning using InvisiClean ultrasonic cleaner for one minute.

        -  Prime and bond universal adhesive layer will be applied, air thinned for 5 seconds and
           cured for 10 seconds The RelyX Unicem clicker 3M ESPE will be used for the restoration
           cementation and final finishing and polishing will be done if any occlusal adjustments
           are done to the restoration
    

Intervention name(s): Cuspal reduction in MOD cavity in endodontically treated teeth; No cuspal reduction in MOD cavity in endodontically treated teeth
Intervention type(s): Other; Other
Intervention description(s): Not only the quality of endodontic treatment that affects the prognosis of the endodontically treated tooth, but the subsequent restorative treatment as well. Coverage, Endocrowns, Onlays, Inlays Restorations on Fracture Resistance of Endodontically Treated Molars, it was found that the worst results came to the inlay restorations and this was attributed to geometric form of preparation that exert a wedging force acting to split the tooth when under occlual stress however, onlay and full coverage direct the force along the long axis by overlaying the cusp tips and a portion of buccal and lingual surface thus opposing the wedging action created by internal design of restoration (Magne P and Belser C. et al 2003) That's why, choosing such a design as a comparator to the design of the cuspal reduction and further coverage (onlay) is crucial to show the importance of cuspal coverage for the indirect resin composite restoration in the endodontically treated teeth.; In an invitro study done by (Ahmed Hamdy 2015) investigating the effect of Full The amount of lost internal tooth structure as well as the coronal hard tissue in an endodontically treated tooth is considered the main factors that make the tooth susceptible to biomechanical failure when compared to a vital tooth. (Guo J et al 2016) .
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment