Sample size
Level of significance = 5%
Power of test = 80%
Population mean = 1.08 5
Test value of population mean = 0.59 9
Pooled standard deviation = 1.2
Sample size = 95 for each technique
The sample size calculated was 95 which was rounded off to 100 for each technique. After approval from the ethical committee of the institute, this randomized clinical trial was carried out on 100 patients who visited the department of Operative Dentistry in a tertiary hospital from January 2019 to August 2019. The patients were selected based on consecutive sampling. Patients of both genders between ages 16–50 years with at least 2 teeth requiring composite restoration were included in the study whereas patients having systemic diseases like uncontrolled diabetes, mentally handicapped, or with parafunctional habits such as bruxism, clenching teeth, etc. were excluded. Teeth with increased pre-operative sensitivity or non-vital teeth with pulp necrosis or with irreversible pulpitis or grossly carious teeth with cavities extending near to the pulp were also excluded from the study. A cold stimulus test was used to ascertain tooth vitality.
The teeth to be restored and the bonding to be applied were randomly selected by the patient himself by picking folded papers. The name of the bonds and teeth numbers were written on 4 different papers. 2 papers with one bond name each, were placed on one side and the other 2 papers with one tooth number written on each paper were placed on the other side. Patients were asked to pick one folded paper from both sides. This defined the bond to be applied to the chosen tooth to be restored. The patients receiving treatment were blinded. Allocation concealment and sequence generation were applied.
Informed consent was obtained from the patients who met the inclusion criteria and were willing to participate in the study, after briefing the aim of the study and its method. The restorations and VAS were performed by a single operator i.e., a qualified dentist, to avoid bias due to technique sensitivity. Since different patients have different pain thresh-holds e.g., moderate pain perceived by a person may be severe and unbearable for the other person. This comparative study was done on two teeth of the same patient by applying Universal adhesive (3M ESPE Scotch bond) on one tooth and Total-etch (3M ESPE Adper Single bond plus Adhesive) on another tooth. This minimizes the variation in pain perception.
Demographic details were obtained. Detailed history followed by clinical examination and pulp vitality test was taken. Patients were educated on marking the intensity of sensitivity of “test teeth” on the continuous visual analog scale (VAS). The hypersensitivity noted before the start of the procedure was taken as a baseline and was noted on the patient proforma. The technique involved the application of cold spray i.e. Tetrafluoroethane (TFE) on a small piece of cotton. This TFE-soaked cotton was then applied to the mid-facial surface of the tooth to measure hypersensitivity. After cavity preparation, Total etch adhesive was applied in the following way: 37% Phosphoric acid was applied for 25 seconds on the prepared cavity. The acid was then washed by air and water pressure through a triple syringe for 20 seconds. Then 2 coats of primer + bond were applied by rubbing through the micro brush for 40 seconds. When the surface became shiny, it was light-cured for 20 seconds.
The other tooth of the same patient was restored by the application of Universal adhesive on the same day, in one sitting. The technique involved in the application of the Universal adhesive system was to prepare the cavity and application of adhesive for 40 seconds by rubbing the entire preparation through a micro brush. The surface was lightly air-dried to remove the residual solvent. The second layer of adhesive was then reapplied, and light cured for 20 seconds. After application of the bond, the composite material was applied in increments of 1–2 mm layer thickness in both cases (Universal adhesive as well as on Total-etch technique). Curing each increment was done for 20 seconds. Sensitivity was recorded immediately after placement of restoration with composite. Finishing was performed after 24 hours with carbide finishing bur and polishing brush. The sensitivity was recorded again at this time. The hypersensitivity was recorded on a 0 to 10 VAS on all three occasions. A total of 110 patients were assessed for eligibility. 7 patients did not meet the eligibility criteria and 3 did not come back after 24 hours for reporting the 3rd reading. So, those patients were excluded from the study as shown in the participant flow. There was no Patient and public involvement in designing or conducting the study.
The data was entered and analyzed in SPSS version 20.0. An Independent sample T-test was applied to compare VAS readings to determine the difference in POH for both bonds and genders. P ≤ 0.05 was considered significant.