Evaluation of Root Roughness and Smear Layer Formation Using Conventional and Contemporary Dental Curettes

INTRODUCTION:

The main objective of scaling and root planing is to smoothen the root surface.Scaling and root planing can be done with a variety of instruments, however, hand instruments are still considered the "gold standard" for treatment. Hand and ultrasonic instruments are primarily used for debridement and produces root surface irregularities which enhances colonization of bacteria, deposition of plaque and retain more calculus.It is also a known fact that these debridement procedures produce a smear layer on the root surface which is detrimental to the healing and regeneration of periodontal tissues, as it interferes with the reattachment of cells derived from the periodontal ligament to the root surface.16

Objective:

The objective of the present study is to evaluate the surface texture of root after hand instrumentation with Gracey curette, After Five curette and Mini Five curette.

Study Design:

A Single Blinded Randomized Control Trial

Study Setting:

The study was conducted in the Periodontology Department of Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences Sample Size Using PASS software version 11, two independent sample t-test, 95% confidence interval, 80% power of test, roughness mean and standard deviation in group 1,hand instrument (1.2 ± 0.3um)54 and group 2,control (1.1 ± 0.56um)54 calculated sample size was 99 which was raised upto 120 teeth.

Sampling Technique:

Consecutive sampling

Clinical Procedure:

120 patients with ages between 35 - 60 years, having severe chronic periodontitis and scheduled for extraction were selected for this study. Detailed history was taken and a consent form was signed by the patient. Lingual surface of each tooth were subjected to debridement with any one of the test curettes. Patients were randomly assigned to any one of the four groups. Randomization was done by computer generated randomizing method. Randomization chart is given at the back.

Subgingival Instrumentation was performed in vivo by a single operator by either 5/6 Gracey Rigid Curette, 5/6 After Five Rigid Gracey curette or 5/6 Mini Five Rigid Gracey Curette. One group was not instrumented and kept as control. Local Anesthesia was given and scaling and root planing was performed until a smooth hard surface was detected by Explorer number 17. Following instrumentation, a small diamond round bur on a high speed hand piece was used to mark the level of the free gingival margin, lingually. This groove provided a landmark for evaluation under scanning electron microscope.

Instrumentation was carried out in vivo by a single operator trained in Periodontology, by a standard protocol. Modified pen grasp technique was used for holding the curettes. The angle between the cutting edge of the curette and the teeth was around 80 degree along with a good finger rest hence permitting a proper wrist-forearm motion. The shank of the instrument was kept parallel to the long axis of tooth. Degree of sharpness was maintained by sharpening the curettes after every 5 strokes with Arkansas stone.( Hu-Friedy Co, Chicago, IL, US) .The tooth were then extracted atraumatically as possible, with the beak of extraction forceps above the gingival margin. After extraction the teeth were rinsed in running tap water for 60 seconds to remove all the debris and blood and placed in 0.9% NaCl solution for hydration until treatment.After instrumentation the samples were fixed in 2.5 % gluteraldehyde solution in phosphate buffer (pH 7.3) for 24 hours and then washed with phosphate buffer 3 times. All specimens were kept for 10 minutes in graded series of ethanol (50%, 70%, 85%, 96% ethanol) for dehydration.139 They were dried overnight and then mounted on a 30 mm diameter aluminum stub with an adhesive tape. The specimens were sputter coated with a 300 Armstrong gold coating in the Auto coater .The scanning electron micrographs were taken from SEM .Each specimen was scored blindly by two investigators specialized in Oral Biology. Six SEM photographs with different standardized magnifications were taken for each specimen which were later assessed using the indices, "Roughness and Loss of Tooth Substance Index" and "Smear Layer Index".17, 57 "Roughness and Loss of Tooth substance index" was analyzed taking the magnifications (×100, ×200, and × 500) into consideration. "Smear layer index" was analyzed using the magnifications (×1000, × 2000, and × 5000) into consideration. For computation of Root Roughness and Smear layer Index a single value was represented by taking mode of the three readings taken on three different magnifications of both indices. The micrographs were assessed by two examiners blinded to the treatment groups. Inter-examiner reliability was checked to ensure the calibration of the examiners by applying Intra-class Correlation Coefficient (ICC) test.

Data was analyzed using SPSS Version 21.Descriptive statistics was computed regarding patients age, gender, brushing and flossing habits. Similarly descriptive statistics regarding teeth were made using frequencies and percentages. Graphs were made like pie chart using frequencies and bar charts using means. Cross Tabulation was made between the test groups (Control, Gracey Curette, After five and Mini Five) versus "Roughness and Loss of Tooth substance Index". Similarly Cross Tabulation was made between the test groups versus "Smear Layer Index". Chi square test was applied to see the grade distribution among groups. P. value of 0.05 or less was considered as significant.