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Browsing by Author "Simmons, Kirt E."
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Item Effects of Flurbiprofen and Orthodontic Stimulation on Osteogenesis in the Rat Mandibular Condyle(1991) Shields, Linda K.; Roberts, W. Eugene; Shanks, James C.; Hancock, E. Bradley; Simmons, Kirt E.; Garetto, Lawrence P.The effects of flurbiprofen administration and/or mechanical stimulation of the teeth upon osteogenesis in the rat mandibular condyle are unknown. To study this problem, 38 male Sprague Dawley rats, between six-eight weeks old, were divided into four groups as follows: 13 rats each in groups stimulated orthodontically and receiving flurbiprofen or stimulated orthodontically and receiving placebo; six rats each in groups not stimulated orthodontically and receiving flurbiprofen or not stimulated orthodontically and receiving placebo. The rats were given weekly intraperitoneal injections of fluorescent bone labels for three weeks, then elastic separators were placed between the maxillary molars in the appropriate 26 rats. Following elastics placement, the appropriate rats received either an intramuscular injection of 0.1 mg/kg flurbiprofen in 1 :1 ethanol and saline buffer or an equal volume of 1 :1 ethanol and saline alone every seven hours for 35 hours following the placement of elastics. All rats received subcutaneous injections of 0.25 μCi/g. 3H-thymidine every seven hours for 35 hours following elastics placement. The animals were euthanized one hour after the final injections. The condyles of each rat were blindly evaluated using nuclear volume morphometry, autoradiography, and fluorochrome analysis. A two-way analysis of variance was used to evaluate for differences among the groups. A post-hoc Newman-Keul's test was employed where needed. A level of significance of p < 0.05 was used. It was found that the rats given flurbiprofen had a higher 3H-thymidine labelling index than the rats given placebo, suggesting flurbiprofen enhances the rate of osteoblast formation and osteogenesis in the rat mandibular condyle, in the short-term. While it is not known how this short-term increased rate of osteoblast formation would correlate to the amount of bone formation clinically, it may be significant. It is possible the potential stimulation of bone formation by flurbiprofen may be useful in the treatment of patients with periodontal disease. Perhaps this potential stimulation of bone formation may also be beneficial in enhancing the jaw growth of orthodontic patients with jaws deficient in size.Item Quantification of Pain Thresholds in Orthodontic Patients Using Strain Gage Techniques(1992) Cordero, José Waldemar; Roberts, W. Eugene; Simmons, Kirt E.; Arbuckle, Gordon R.; Hohlt, William F.; Shanks, James J.The purpose of this study was to assess the suitability of a pain model that utilizes the application of force between teeth as the noxious stimulus. Also, the time course of pain threshold alterations in patients subjected to orthodontic treatment was explored. A simple pressure algometer utilizing strain gages was produced to apply and measure the force required to reach the pain threshold of incisor teeth (central-lateral pairs) for three consecutive days. Fifteen orthodontic patients were used (nine females, six males) with incisors in good alignment and with interproximal contact. Each patient was used for both control and experimental measurements in each arch. Baseline pain threshold measurements were taken on the first day and individual orthodontic springs placed on the experimental side. The control side was the adjacent central-lateral incisor pair on the other side of the arch where no spring was placed. Additional measurements were taken the second and third day in each quadrant. A great variability in pain response between patients was evident. Significantly lower pain threshold levels were observed a day after the initial spring activation followed by an increase in the pain threshold the second day after spring activation. In the mandibular arch, the treatment by day interaction was significant, with the experimental side pain threshold substantially lower than control on the second and third day. Pain thresholds in males were significantly higher only in the maxilla, although there was a tendency for lower pain sensitivity in males for both arches. An apparent crossover of sensitivity between arch sides was observed in this study. The present model was shown to be suitable to study pain thresholds associated with orthodontic forces, and the pressure algometer was able to quantify pain threshold with objective measurements. The model could be used clinically to screen patients with low pretreatment pain thresholds so modifications of treatment mechanics or pharmacologic means could be used to allay patient pain.Item Tensile Bond Strength of Light-Activated Glass Ionomer for Bonding Metal and Ceramic Brackets(1990) Wentz, Todd Zane; Roberts, W. Eugene; Moore, B. Keith; Shanks, James C.; Hennon, David K.; Garetto, Lawrence P.; Simmons, Kirt E.Visible light-activated glass ionomer offers several advantages over conventional autopolymerizing adhesives, such as extended control of working time, immediate ligation, fluoride release, and a chemical bond to enamel. This study compared in vitro tensile bond strength of a new light-activated glass ionomer with that of a chemically-cured glass ionomer for bonding ceramic and metal orthodontic brackets. The manufacturer's recommended light-activation time of 30 seconds was evaluated by Knoop hardness testing. Specimens cured for 30 and 60 seconds were evaluated with Knoop hardness testing at various time intervals over a 24-hour period. An evaluation of the data indicated that the manufacturer's recommended cure time was adequate. Human maxillary premolars were divided into six groups of 20. Each group was bonded with either light-activated glass ionomer or a chemically-cured glass ionomer utilizing either metal or ceramic brackets. After bonding, specimens were thermocycled and stored in water at 37°C for 14 days. After the 14-day storage period specimens were tested in the tensile mode of an lnstron testing machine until failure. Ceramic brackets were found to have a significantly greater mean tensile bond strength than metal brackets when light-activated glass ionomer was used as the bonding agent. Mean tensile bond strength of metal brackets bonded with light-activated glass ionomer were significantly greater than metal brackets bonded with a chemically-cured glass ionomer. Ceramic brackets had a negligible bond strength when bonded with a chemically-cured glass ionomer. The light-activated glass ionomer tested in this study appears to have an adequate in vitro mean tensile bond strength to be considered for an orthodontic bonding adhesive.