IU Indianapolis ScholarWorks :: Browsing by Author "Miller, James R."

Browsing by Author "Miller, James R."

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Apert Syndrome : A Descriptive Analysis of Selected Computed Tomographic Images of the Craniofacial Complex
(1988) Schafer, Alan Boulware; Garner, LaForrest D.; Bixler, David; Hennon, David K.; Kasle, Myron J.; Miller, James R.; Shanks, James C.
The purpose of this study was to demonstrate how selected computed tomographic images of the craniofacial complex may be used in a descriptive evaluation of cranial dysmorphology in living subjects with Apert syndrome. Computed tomographic images using coronal sections through the optic disc, planum sphenoidale, and axial sections through petrous ridges, pterygopalatine fossa, and midorbital level from two Apert syndrome and two non-syndrome controls were evaluated. Reference lines were established using actual and constructed landmarks. The results were tabulated for all four subjects. The two Apert subjects (in contrast to the non-syndrome subjects) demonstrated the following: a) orbital proptosis with a reduced bony orbital depth and elongation of the orbits in a superior direction with an altered vertical orbital axis b) increased lateral orbital wall angle c) alteration of the anterior cranial base with depression of the ethmoid complex d) midface regression Interestingly, ocular hypertelorism, which has been reported to be a feature of Apert syndrome, could not be confirmed by use of these CT scans. The findings obtained from this study are consistent with the published characteristics of Apert syndrome. In conclusion, this study demonstrates the utility of computed tomographic images in the evaluation of craniofacial dysmorphology.
Clinical Evaluation of Glass Ionomer Cement as an Adhesive for the Bonding of Orthodontic Brackets
(1988) Miller, James R.; Garner, LaForrest D.; Moore, B. Keith; Shanks, James C., Jr.; Barton, Paul; Potter, Rosario H.
Glass ionomer cement has been shown in previous studies to retard decalcification and caries formation. This cement would be valuable in orthodontics if it proved to have adequate adhesive properties. Therefore, this study was designed to determine if there is a significant difference in the failure rate of brackets attached to teeth using a glass ionomer cement, Ketac-fil, and the failure rate of brackets attached to teeth using a conventional orthodontic adhesive system, Rely-a-bond. Six patients in the Department of Orthodontics at Indiana University School of Dentistry participated in this study. Each patient had 16 to 20 teeth available for bracketing. Direct-bond orthodontic brackets were attached to one-half of each participant's available teeth using Ketac-fil. Rely-a-bond was used to bond brackets to the remaining half of the teeth. Fifty-three brackets were placed with Ketac-fil, and 53 with Rely-a-bond. This study lasted a minimum of ten weeks for each patient. The following observations were made: 1) The failure rates for brackets attached with Ketac-fil and those attached with Rely-a-bond. 2) The type of bracket failure for brackets bonded with Ketac-fil. 3) Pre-study and post-study decalcification patterns of teeth with brackets attached with Ketac-fil. The bracket failure rate was 3.77% for the Ketac-fil group and 5.66% for the Rely-a-bond group. There was no significant difference between the failure rates of these two groups at the alpha = 0.05 level when tested with the Fisher Exact Probability Test. Of the two brackets that failed in the Ketac-fil group, only one was available for examination and it demonstrated a definite adhesive type of bracket failure. With respect to decalcification patterns, no obvious change in pattern occurred for teeth in the Ketac-fil group. There was no statistical difference between the failure rates of brackets attached with Ketac-fil and those attached with Rely-a-bond. Previous studies have shown that glass ionomer cements release fluoride and that this may retard decalcification and caries formation. Decalcification and caries formation around the margins of orthodontic brackets have been identified as potential risks of orthodontic treatment. Thus, the use of a glass ionomer cement as a bonding agent in orthodontics might reduce these potential risks without compromising the attachment of the brackets to teeth. This study provides the basis for more extensive clinical trials of glass ionomer cements as bonding agents for direct-bond orthodontic brackets.
Evaluation of Tensile Bond Strength of a Fluoride-Releasing Resin Adhesive with Ceramic Brackets
(1991) Lehman, David Alan; Roberts, W. Eugene; Moore, B. Keith; Shanks, James C.; Arbuckle, Gordon R.; Miller, James R.
The increased attention to the esthetics of orthodontic appliances has led to the popularity of ceramic brackets in the last decade. Although the bonding of ceramic brackets has become predictably successful, the extreme brittleness of ceramics coupled with higher bond strengths has caused significant clinical problems in debonding and risk of enamel damage. This study evaluated an experimental bonding resin with different levels of fluoride concentration, linking the therapeutic property of long-term fluoride release to the benefit of decreased bond strength to ceramic brackets. Four groups of 40 Transcend™ ceramic brackets each were bonded to bovine teeth, using 0, 3, 6, and 12 percent fluoride concentrations. At two weeks, one-half of each group was tested for tensile bond strength in an lnstron machine. The remaining half were tested at six months. In the groups broken at two weeks, the bond strength peaked around 6 percent fluoride, but the three top groups were not significantly different. In the groups tested at six months, peak strength was observed at 3 percent fluoride and was significantly greater than the others. The overall mean at six months than at two weeks. The study found bond strength values in the range of 25-50 kg/cm2. Although minimum values have not been established, the low values reported in this study are likely to be within acceptable clinical limits. Following debonding, the mode of bond failure was determined by viewing enamel specimens and bracket bases under a light microscope. In all but one group, 95 percent of the bond failure occurred at the bracket base/adhesive interface. No bracket failure occurred and no enamel damage could be observed under the light microscope. In a parallel study of physical properties, Knoop hardness was measured at one hour, 24 hours, and six months, and compressive strength was tested at one week and six months. While physical properties generally decreased over the period of study, bond strength was significantly greater in the six-month group. The results of this study regarding the correlation of these properties to bond strength is inconclusive. In addition, results of fluoride-release data by SISCO Inc. indicate that the 12 percent group was shown to release greater than 10 μg/g/day at six months. This was comparable to amounts known to have the clinical benefit of reducing demineralization, and equaled or exceeded other commercially available fluoride-releasing adhesives. The results of this study indicate that a fluoride-releasing resin can release clinically significant amounts of fluoride ions, and still have adequate bond strength.
Evaluation of the Tensile Bond Strength of Orthodontic Bracket Bases Using Glass Ionomer Cement as an Adhesive
(1992) Burns, Richard D., Jr.; Roberts, W. Eugene, Jr.; Garetto, Lawrence P.; Moore, B. Keith; Miller, James R.; Shanks, James C., Jr.; Hennon, David K.
The search for an orthodontic bonding adhesive that has chemical adhesion to enamel and releases fluoride into the oral environment has led to experimentation with glass ionomer cements. This study compared the tensile bond strength of eight different orthodontic bracket base designs in vitro and assessed the amount of adhesive remaining on the bracket pad after debonding. Each bracket base design included in this study had unique characteristics warranting their inclusion. The groups contained brackets with 60, 80, and 100 gauge mesh pads; 100 gauge mesh sandblasted pads; perforated metal bases; Micro-Lock™ photo-etched bases; Dyna-Lock™ integral bracket/bases; and ceramic silane-coated bracket pads. Groups contained 20 to 22 specimens that were bonded to bovine incisor teeth embedded in a self-curing acrylic block that could be held in the testing machine. Pre-encapsulated glass ionomer cement (Ketac-Fil™) was the experimental adhesive. The adhesive was mixed according to the manufacturer's instructions in a dental amalgamator. The specimens were thermocycled between water oaths of 15°C and 55°C. The specimens spent 30 seconds in each bath for a total of 2,500 cycles and were stored in a humidor until debonding. After 14 days, the specimens were subjected to a tensile force using an Instron mechanical testing machine until failure occurred. The Micro-Loc™ photo-etched base had significantly higher mean tensile bond strength (p<0.05) than all other brackets tested. The ceramic brackets were unable to be tested due to the extremely weak bond strength which did not allow preparation of the samples for debonding. Following debonding, the percentage of adhesive remaining attached to the bracket base was determined using a grid in the ocular of a light microscope. In general, the site of bond failure involved the base/adhesive interface. The Dyna-Lock™ integral bracket/base and 80 gauge mesh base had a greater mean percent of adhesive remaining attached to the base. (Dyna-Lock™ 45 percent and 80 gauge mesh 43 percent vs. all other < 20 percent.) The results indicate that the bracket base design can influence the bond strength when GIC is used as an orthodontic adhesive and suggests that development of GIC with increased fracture toughness might increase bond strength.
A Survey of Sterilization/Disinfection Techniques Used By Orthodontists in the U.S.
(1986) Burns, Richard H.; Garner, LaForrest D.; Barton, Paul; Dirlam, James H.; Miller, James R.; Stone, Edward
Questionnaires were sent to 500 orthodontists in all states of the U.S., inquiring about the methods of sterilization used for hand instruments (mirrors, explorers, band pushers, etc.) and hinged instruments (pliers). The practitioners were asked if their sterilization/disinfection methods had been changed recently, and if any changes in methods were due to the risk of disease transmission. Opinions were also solicited regarding the importance of complete sterilization (i.e., destruction of all organisms). An opportunity was provided to rate the effectiveness of the sterilization method in use. Finally, information was requested on any barrier methods used routinely. The most commonly used method for hand and hinged instruments was cold sterilization with a 2% glutaraldehyde solution. This solution was used by 46.5% of the office for hand instruments, and by 33.5% of the offices for hinged instruments. Quaternary ammonium compounds were used by 26.5% of the offices for hand instruments, and by 19.2% for hinged instruments. Wiping with alcohol was used by 30.4% of the offices for hinged instruments. The most common heat sterilization method used was the chemiclave system (11.5% for hand instruments and 9.1% for hinged). Of the offices surveyed, 45.5% had changed their methods within the past two years. Of that group, 66.9% had changed as a result of the increased problem with transmissible diseases. Of the offices that had not changed recently, 64.1% were considering doing so as a result of the disease transmission concern. Complete sterilization was considered very important by 47.5% of respondents, while 41.6% ranked it somewhat important. Of the orthodontists surveyed, 16.1% felt that they achieved an excellent level of asepsis in their offices, followed by 58.7% who rated it good, 23.4% average, and 1.4% poor. Protective eyewear was worn by 52.4 % of those surveyed, while gloves and masks were worn routinely by 21.3% and 21.6% of the practitioners, respectively. On the basis of the literature review, the most effective cold sterilization method (other than ethylene oxide) for the orthodontic office appears to be a 2% glutaraldehyde solution. This technique will not corrode plier joints or the stainless steel surfaces. The best heat sterilization method for the orthodontic office is the chemiclave system, due to its lack of corrosion problems, as well as its relatively rapid cycle time. Ultrasonic cleaning of all instruments prior to sterilization is highly recommended.
The Validity of Articulare for Measurement of Mandibular Length
(2001) Martinez, Fernando Luis; Roberts, W. Eugene; Baldwin, James J.; Haas, Dennis W.; Miller, James R.; Shanks, James C.
Mandibular length is commonly defined as the linear distance between condylion and pogonion. The use of condylion in mandibular length and growth measurements, however, is technically difficult because condylion is often obscured in the standard closed-mouth lateral cephalogram. As a result, many studies have utilized articulare as a substitute for condylion because it is readily identifiable in most lateral cephalometric films and is reasonably close in proximity to condylion. To date, very few studies have examined the validity of articulare and the literature provides conflicting reports. The present study examines the validity of articulare in mandibular length measurements by taking three cephalograms on each of 60 consecutive patients: 1) closed-mouth with the patient in habitual occlusion, 2) closed-mouth lateral with the patient in centric relation, and 3) an open-mouth lateral cephalogram. The linear distances (mm) of Ar-Pog, Ar-Go, and Go-Pog were measured on the two closed-mouth cephalograms and compared with each other as well as the linear distances of Co-Pog, Co-Go, and Go-Pog measured from the open mouth cephalogram on each individual. Product-moment correlation coefficients were used to measure the linear associations between the mandibular measurements from the three techniques. Repeated measures analysis of variance were also fit to estimate the correlations between the three measurements adjusted for age and gender. The results of this study show that measurements taken from both closed-mouthed techniques agreed extremely well (ICC=.99). In addition, measurements from both closed-mouth techniques correlated very highly with corresponding measurements taken with the open-mouth technique (ICC=.94). This data suggests that measurements taken from Ar correlate very well with measurements taken from Co and that this correlation is not dependent on whether the patient is positioned in habitual occlusion or centric relation.

Browsing by Author "Miller, James R."

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