Non carious maxillary/mandibular permanent incisors

Materials And Methods

The present in vitro study was conducted in the department of Pedodontics and preventive dentistry, Himachal Dental College, Sundernagar, Himachal Pradesh. A total of 90 human permanent incisors were collected from the outpatient department of Oral Surgery in Himachal Dental College, Sundernagar which were extracted for periodontal reasons.. The testing procedure using ICP-OES equipment. (Inductively coupled plasma - optical emission spectrometry) was carried out in the ITC labs, Panchkula.

Inclusion Criteria :

• Single root canal
• Closed apices
• Intact roots

Non carious maxillary/mandibular permanent incisors

Exclusion Criteria :

Teeth with restorations, cracks and open apices

Armamentarium

• 1) Diagnostic set (Probe, mirror and tweezer)
• 2) Kidney tray
• 3) Metal scale and divider
• 4) Maxillary and mandibular permanent incisors
• 5) Ultrasonic cleaning tips
• 6) Curette
• 7) Air rotor hand piece (NSK, Nakanishi INC, Shimohinata, Japan)
• 8) Air rotor burs
• 9) Stainless steel hand K- files 2% (MANI)
• 10) Broaches
• 11) Glass slab
• 12) Spatula
• 13) Paper points
• 14) Reamer
• 15) Plugger
• 16) Containers
• 17) Incubator
• 18) pH meter
• 19) Inductively coupled plasma - optical emission spectrometry

Materials :

• 1. 10% buffered formalin solution
• 2. 3% Sodium hypochlorite (Prime Dental Products)
• 3. 0.9% Normal saline
• 4. 17% EDTA Solution (Prevest DenPro Limited)
• 5. Cotton pellet
• 6. Calcium hydroxide (Prevest DenPro Limited)
• 7. Barium sulphate ( Nice Chemicals Pvt. Ltd)
• 8. Temporary filling material (cavit) (Prevest DenPro Limited)

Preparation of samples

90 extracted human single rooted teeth used in this study were soaked in 3% sodium hypochlorite solution for 30 minutes to remove organic debris. Subsequently they were scaled with ultrasonics, washed with distilled water for the removal of any calculus or soft tissue debris and then stored immediately in 10% buffered formalin solution until use.

Teeth were washed well in water to remove the traces of formalin preserving solution and dried using oil free compressed air.

The selected teeth were divided into 2 groups: group 1 and 2 of 45 teeth each on the basis of placement of calcium hydroxide.

Groups No. of teeth

Method

Access cavity and working length

• A single operator instrumented all teeth, which were held in hand.
• In groups A and B standard access cavity preparation was done using high speed straight handpiece with water spray and #2 round bur and straight bur.
• The entire canal contents were grossly debrided with broaches and irrigated with normal saline and sodium hypochlorite.
• The canal length was established with #10 endodontic file just visible through the apical foramen.
• The working length was determined by subtracting 1 mm from the total canal length and was measured on the metal scale with the help of divider.

Biomechanical preparation

• Root canal preparation was done using 25mm k files by quarter - turn - pull technique in a step back manner.
• The size 10 file followed by size 15 file was inserted directly through the canal orifice to the desired length.
• The root canals were serially enlarged at the apical foramen to size 45.
• Step-back flaring was produced by using #50, #55, #60, #70 k files set respectively at 1, 2, 3 and 4 mm short of working length.
• Before each progression from one file to the next larger one, patency of the apical foramen was determined by placing a #15 k file through the foramen 1mm past the apex.

Irrigation

• Irrigation during cleaning and shaping was performed using 10 ml of 3% of sodium hypochlorite solution and normal saline.
• A 17% EDTA gel was used as a chelating agent and was introduced in the canal on the tip of each successive instrument.
• Irrigation was performed using 5 ml disposable plastic syringes with 27- gauge needle tips placed passively into the canal, upto 3 mm from the apical foramen without binding.
• After instrumentation, root canals were again irrigated with 10 ml of 3% sodium hypochlorite, then 3 ml of 17% EDTA, followed by a final flush of 3 ml sodium hypochlorite and 10 ml normal saline.

Placement of calcium hydroxide

Calcium hydroxide paste was then mixed with normal saline on a glass slab with the help of cement spatula to a relatively thick paste. Barium sulphate was added for the radiopacity.

Group 1 (n=45)

The access cavity was dried with cotton pellet and root canals were dried with paper point and calcium hydroxide paste was filled in the root canals with the help of reamer and plugger until the calcium hydroxide paste was visible at the apical foramen.

Group 2 (n=45)

The access cavity was dried with cotton pellet and the root canal remained wet after root canal preparation in order to allow hydroxyl and calcium ions to be released. The calcium hydroxide paste was inserted into the pulp chamber by spatula and condensed with the help of condenser.

All the access cavities were then filled with Cavit to a depth of 3mm. All the root surfaces except for the apical 2mm were covered by two layers of nail polish.

• The radiograph of the each tooth was taken using paralleling technique. The distance between the tooth and source, tooth and film and the exposure factors was standardized.
• The samples were then immersed in capped containers containing normal saline individually.
• The samples were then stored in an incubator at 37?c and 100% humidity which were then further subdivided into subgroup A,B and C of 15 teeth each according to the different time intervals i.e 2 days, 1 week and 2 weeks.
• The calcium ion concentration in the normal saline was determined after 2 days in the ICP-OES machine was measured in ppm and pH was determined with the help of pH meter.
• Similarly the calcium ion concentration and pH were determined after 1 week and 2 weeks respectively and the readings were obtained.
• The Mean and the standard deviation of the readings were calculated and the data was analyzed using Anova test and t-test.