Clinical evaluation of a one-bottle bonding system for desensitizing exposed roots

Purpose: To evaluate the effectiveness of a one-bottle adhesive system as a desensitizing treatment, with or without a prior phosphoric acid-etch step . Materials and Methods: Two different clinical procedures using a one-bott le adhesive bonding system were tested for its efficacy on desensitizing ex posed roots. Thirty subjects with a history of dentin hypersensitivity were selected and 60 exposed sensitive teeth were divided into two groups (n = 30). In Group 1 samples, Scotchbond 1 bonding system (Single Bond in USA) w as applied without a prior acid-etching, while in those of Group 2, the exp osed sensitive roots were acid-etched with 35% phosphoric acid for 15 secon ds, prior to application of bonding agents. The sensitivity was evaluated a t 0, 1, 2, 4 weeks and 3 months using cold air blast stimuli, and recorded using a visual-analogue scale. The scores were analyzed as non-parametric d ata by means of the Mann-Whitney and Sign tests. Five samples from each gro up were randomly selected in order to make scanning electron microscope obs ervations of the sensitive dentin surfaces at baseline and at each recall u sing the replica technique. Results: At baseline, after both desensitizing procedures all the patients reported distinct reductions in dentin sensitiv ity. At 1- and 2-week recalls, 20 teeth of Group I and 17 teeth in Group 2 exhibited a return of sensitivity, and in five teeth in each group, the sen sitivity score was between 5-8. During the first recall (1-2 weeks), the se nsitive teeth were retreated and showed an immediate reduction of sensitivi ty. At the 1-month recall, eight teeth in Group 1 and four teeth in Group 2 showed a return of some sensitivity, and in six teeth in Group 1 and in th ree teeth in Group 2, old amalgam restorations were replaced and this proce dure almost completely resolved the sensitivity. At the 3-month recall, onl y five teeth from each group showed residual mild sensitivity (score 1-2). For both Groups 1 and 2 there was a statistically significant (P < 0.0005) reduction in sensitivity levels between the baseline pain scores and immedi ately after treatment, and between the first recall pre-treatment pain scor es and the last recall pain scores. Overall, the two methods of treatment d emonstrated a general decrease in sensitivity in both groups over the 3-mon th study period, adequately solving the clinical and patients' perception o f the discomfort of sensitivity. The SEM observations of the replicas showe d a progressive loss of the adhesive resin from the treated surfaces. This fact was more evident in the non-etched samples (Group 2) than in those in Group I. The results of this study showed that exposed root dentin sealed w ith Scotchbond 1, with or without prior acid-etching, did not show spontane ous sensitivity after 3 months.