Effect of a new local anesthetic buffering device on pain reduction during nerve block injections.

The purpose of this double-blind, split-mouth, randomized human clinical study was to evaluate the effectiveness of a new sodium bicarbonate local anesthetic buffering device (Onset) in reducing pain associated with dental injections. Twenty patients were given bilateral inferior alveolar (IA) and long buccal (LB) nerve block injections and asked to quantify the pain experienced during injection on a visual analog scale (0, no pain; 10, worst possible pain). One side of the mouth received standard-of-care injections of 2% lidocaine with 1:100,000 epinephrine. On the opposite side, after the buffering device was used to mix the components within the anesthetic carpule, patients received injections of 2% lidocaine with 1:100,000 epinephrine buffered 9:1 with 8.4% sodium bicarbonate. The mean pain scores were 2.7 (SD, 1.3) for buffered and 2.7 (SD, 1.9) for unbuffered IA injections. The mean pain scores were 2.0 (SD, 1.4) for buffered and 2.7 (SD, 1.8) for unbuffered LB injections. The data were analyzed with a paired t test (α = 0.05), and no statistically significant difference was found between groups for IA (P = 0.94) or LB (P = 0.17) nerve block injections. In this study of patients receiving common dental nerve block injections, local anesthetic buffering technology did not significantly lessen pain compared to that experienced during a standard unbuffered injection.

An in vitro comparison of antimicrobial toothbrushes.

The purpose of this study was to determine the efficacy of toothbrushes that advertise self-disinfecting, antimicrobial properties due to the inclusion of silver nanoparticles or chlorhexidine in the bristles. Three different types of toothbrushes-silver nanoparticle, chlorhexidine-coated, and a control-were submerged in suspensions of Streptococcus mutans and Candida albicans. At designated times postinoculation, organisms were removed from the toothbrush heads, then serially diluted, plated, and incubated. The colony-forming units (CFUs) were counted and a mean percent reduction was determined for each organism group. With the S. mutans groups, the chlorhexidine-coated toothbrushes had significantly greater percent reduction in CFUs at all 3 time points compared to the control or silver nanoparticle toothbrushes. With the C. albicans groups, neither the chlorhexidine-coated nor the silver nanoparticle toothbrushes had a significant reduction in CFUs compared to the control. Neither of the antimicrobial toothbrushes delivered the advertised claim of a 99.9% reduction in CFUs with either microorganism. However, the inclusion of chlorhexidine in toothbrush bristles appeared to be the most promising of the methods tested for toothbrush self-disinfection.

Effects of a vibratory device on pain from anesthetic injections.

BACKGROUND: A randomized block, split-mouth design was used to determine the effectiveness of a vibratory device with topical anesthetic compared to topical anesthetic only in reducing the pain experienced during an inferior alveolar nerve block. METHODS: Twenty participants each received two inferior alveolar injections with a 5-minute interval between injections, one with topical anesthetic and one with topical anesthetic and a vibratory device. Each injection included a 2-minute application of topical anesthetic gel at the injection site. Local anesthetic was administered bilaterally using a 27-gauge needle with or without the vibratory device. Participants rated the pain they experienced after each injection by using a visual analog scale (VAS). A mean VAS score and standard deviation was determined per group. Data was analyzed with a paired t test (α = 0.05). RESULTS: The group receiving the vibratory device with topical anesthetic had a mean VAS score of 21.2 mm ± 18.6 mm, and the group receiving the topical anesthetic alone had a VAS score of 38.7 mm ± 23.3 mm. CONCLUSION: The use of the vibratory device and topical anesthetic significantly reduced the pain experienced during the administration of a local anesthetic injection compared with the use of topical anesthetic alone (P = 0.006).

Periodontal wound healing with and without platelet-rich plasma: histologic observations and assessment of flap tensile strength.

BACKGROUND: Platelet-rich plasma (PRP) has been promoted as a surgical adjunct to enhance hard and soft tissue wound healing. Although anecdotally reported to be of value, the results of controlled studies examining the added effects of PRP on surgical procedures have been mixed. The purpose of this study was to test the effect of PRP on flap strength at various post-surgical time points in a minipig animal model. METHODS: Twelve Yucatan minipigs provided four sites per animal. PRP was prepared from each animal at the time of surgery. Following reflection of a mucoperiosteal flap in each quadrant, subgingival plaque and calculus were removed. Each surgical site was irrigated with sterile saline; prior to suturing, one randomly selected test quadrant in each arch was treated with PRP. Four animals were euthanized at day 14, and two animals were euthanized at 2, 7, 10, and 28 days. The flap strength in each quadrant was tested by attaching to a loop of 3-0 silk suture through the tissue; the force required to separate the flap from the tooth/bone interface was recorded for each site. A separate portion of each flap site was prepared for descriptive histologic examination, including inflammation, hemorrhage, and new bone growth. RESULTS: Flap strength was significantly less on day 2 compared to later time points, and there were no significant differences between the test and control groups. No histologic differences in healing between test and control sites were seen at any time point. CONCLUSIONS: PRP did not seem to contribute to greater flap strength at any post-surgical time point, nor was it associated with any histologic differences in wound healing in this Yucatan minipig model. The time points chosen for observation post-surgery, as well as the variability in the PRP platelet count, may have contributed to the lack of positive findings in this study.

Human gingival fibroblast integrin subunit expression on titanium implant surfaces.

BACKGROUND: Implant surface characteristics have been shown to modify cell behavior and regulate integrin expression. Integrin expression and resultant integrin-mediated cellular activity are essential components of tissue healing and homeostasis. Although both osseous and soft tissue healing around dental implants are critical to clinical success, there is limited information available on the effect of implant surfaces on integrin expression in soft tissues. Therefore, the aim of this study was to examine integrin expression for gingival fibroblasts on titanium surfaces and the influence of titanium surface roughness on integrin expression and cell morphology. METHODS: Human gingival fibroblasts were cultured on smooth (polished) and rough (sand-blasted acid-etched) titanium surfaces and a cell culture plastic (control) surface. To analyze integrin expression, total RNA was isolated from experimental and control cells, and levels of integrin subunit mRNA were assessed by reverse transcription-polymerase chain reaction (RT-PCR) using primers specific for the alpha2, alpha4, alpha5, alpha(v), and beta1 integrin subunits and aldolase (internal control). PCR products were analyzed by polyacrylamide gel electrophoresis (PAGE), confirmed via DNA sequencing, and quantified using computer-assisted densitometry. The expression of the integrin subunits was analyzed at the protein level using flow cytometry, as well as fluorescence and confocal laser microscopy. Cell morphology was evaluated using scanning electron microscopy (SEM). RESULTS: Our experiments demonstrated cellular expression of the alpha2, alpha4, alpha5, alpha(v), and beta1 integrin subunits at both mRNA and protein levels on all surfaces. In addition, the alpha4 and beta1 mRNA levels were significantly increased on smooth titanium relative to plastic surfaces (P <.05) with intermediate mRNA levels found on the rough titanium surfaces. The smooth titanium surfaces exhibited a flat monolayer of cells, while rough titanium surfaces showed cells orienting themselves along surface irregularities. CONCLUSIONS: These results demonstrate the presence of multiple integrin subunits in human gingival fibroblasts grown in contact with titanium implant surfaces and that titanium surface roughness alters cellular morphology but appears to have limited effects on integrin expression. This study provides insight into the complicated cellular and molecular events occurring at the implant surface that may be critical to optimizing the soft tissue interactions with the soft tissue-implant interface.