1.
The effect on shear bond strength of rewetting dry dentin with two desensitizers.
Al Qahtani, MQ, Platt, JA, Moore, BK, Cochran, MA
Operative dentistry. 2003;(3):287-96
Abstract
The difficulty related to achieving a balance between wet and dry dentin makes the dentin bonding technique extremely sensitive. This study evaluated the effect of rewetting dried dentin with two commercial desensitizing agents (Protect and HurriSeal) on the dentin shear bond strength of three total-etch dentin bonding agents (Syntac Single-Component, OptiBond Solo Plus and Prime & Bond NT) and compared both to applying these same bonding agents to moist dentin and dry dentin. Each bonding agent was paired with an appropriate resin composite from the same manufacturer (Table 1). Recently extracted, formalin-treated caries-free human molars were used. The occlusal surface of each tooth was ground to create a flat dentin surface. Then, each tooth was mounted in acrylic. Twelve groups (n = 15) were prepared: 1) Syntac Single-Component with Heliomolar resin composite (SSC/H) to moist dentin; 2) SSC/H to dry dentin; 3) SSC/H to dried dentin rewet with Protect; 4) SSC/H to dried dentin rewet with HurriSeal; 5) OptiBond Solo Plus with Point 4 resin composite (OBS+/P4) to moist dentin; 6) OBS+/P4 to dry dentin; 7) OBS+/P4 to dried dentin rewet with Protect; 8) OBS+/P4 to dried dentin rewet with HurriSeal; 9) Prime & Bond NT with TPH Spectrum resin composite (PBNT/TPH) to moist dentin; 10) PBNT/TPH to dry dentin; 11) PBNT/THP to dried dentin rewet with Protect and 12) PBNT/TPH to dried dentin rewet with HurriSeal. Groups 1, 5 and 9 were placed according to manufacturers' instructions (moist dentin) as control groups. All the other groups received a 15-second air blast after etching and prior to applying the one bottle adhesive or desensitizer and one bottle adhesive. Resin composite cylinders [4 mm in diameter and 2 mm in height] were then placed. The specimens were stored in distilled water at 37 degrees C for 24 hours prior to thermocycling 2,500 times (at 8 degrees C and 48 degrees C). Shear bond strengths (SBSs) were measured one week after fabrication by using a circular knife-edge and crosshead speeds of 0.5 mm/minute. Failure modes of debonded specimens were determined under a stereomicroscope (30x). Failed specimens with the low and high shear bond strengths in each group were evaluated under a low vacuum Scanning Electron Microscope (SEM-LV). One-way ANOVA and Tukey's tests were used to compare the different conditions for each bonding system. In the Syntac Single-Component bonding agent groups, there was no significant difference in shear bond strength between the control (15.73 MPa), dry (18.11 MPa) and HurriSeal (16.18 MPa) specimens. Protect specimens showed significantly lower shear bond strength (6.39 MPa). In the OptiBond Solo Plus bonding agent groups, there was no significant difference between the control (20.79 MPa) and the HurriSeal (21.29 MPa) groups, and both groups had significantly greater bonds than the dry (14.13MPa) and Protect (9.57 MPa) groups. In the Prime & Bond NT bonding agent groups, the shear bond strength of the HurriSeal group (20.73 MPa) was significantly higher than the other groups: control (8.05 MPa), dry (5.73 MPa) and Protect (5.45 MPa).
2.
Effect of a novel ceramic filling material on plaque formation and marginal gingiva.
Konradsson, K, van Dijken, JW
Acta odontologica Scandinavica. 2002;(6):370-4
Abstract
The aim of this clinical investigation was to evaluate a novel ceramic (CF) filling material (DoxaDent) compared to resin composite (RC) and enamel in regard to plaque formation and gingival inflammation. The CF material is inorganic, non-metallic, and contains calcium aluminate, silicate, and water. To make intra-individual comparisons possible, each participant had at least one set of three test surfaces: two Class V restorations with subgingival cervical margins (one of the novel CF material and one of a hybrid RC) and one non-filled enamel surface (E). The amounts of plaque, gingival crevicular fluid, and clinical signs of gingival inflammation were intra-individually compared in 20 sets of the three test surfaces. In a cross-sectional study (CSS), the effect of oral hygiene on plaque formation and gingivitis around the surfaces was evaluated. In a following 10-day experimental gingivitis study (EGS), plaque formation and the induction of gingivitis during refrain from oral hygiene was compared. In the CSS, no significant differences were found between the surfaces in terms of amount of plaque and degree of gingival inflammation. At the end of the EGS the restorative materials showed a significantly higher amount of plaque (CF versus E, P = 0.014; RC versus E, P = 0.034), but no significant differences were found in degree of gingival inflammation. In condusion, the ceramic filling material was comparable to RC regarding plaque formation and gingival inflammation with customary oral hygiene. With neglected oral hygiene, significantly less plaque growth and a non-significant tendency toward lower amounts of gingival crevicular fluid were observed on enamel surfaces.