The differences in the response of patients to the same orthodontic treatment are, to a great extent, the result of variability in the direction and rate of craniofacial growth. Furthermore, there is currently little scientific evidence that the temporary improvement of skeletal relationships from orthopedic appliances will alter the craniofacial skeleton on a permanent basis. However, contemporary literature is beginning to show that certain appliances may be more effective than others at a specific point in the growth process. Timing of treatment in a patient is becoming of increased clinical importance. A review of the anatomy of palatal expansion indicates that expansion is much greater in the anterior portion of the palate, in both horizontal and vertical planes. Assessment of skeletal maturity for treatment timing and growth prediction is most commonly performed with the hand/wrist radiograph. A new method is presented which uses epiphyseal and diaphyseal widths and fusion of selected phalanges to determine the relative position of the individual on the pubertal growth curve. Skeletal maturity assessment is a traditional attempt to judge physiological development. The future of craniofacial growth assessment lies in the development of physiological measurements which are both replicable and valid and clinically feasible. The data from these studies provides information to allow better quantitative diagnosis and treatment as well as objective assessment of the treatment outcome.

Superelastic mechanical behavior of nitinol alloy orthodontic wires is thought to be the result of a stress induced crystallographic transformation from austenite to martensite, The purpose of the study was to compare the SE mechanical behavior of nitinol wires to stress-induced phase changes, Eight nitinol arch wires having rectangular cross-sections were strained from 0% to 10% in tension with a mechanical testing machine. Load/extension plots were subjectively ranked for SE behavior. X-ray diffraction patterns were collected with and without 6% strain. Without strain, nitinol wires were found to be predominantly austenite with some wires containing a small amount of martensite. When strained 6%, superelastic wires demonstrated a phase transformation from austenite to martensite. XRD patterns were ranked for percent transformation and 110 peak width, Product rankings of the degree of superelasticity were positively correlated with the rank of martensitic transformation (p < 0.05). Superelasticity ranks were negatively correlated with XRD peak width ranks (p < 0.01). Increased peak width indicates greater cold work, A range of superelastic mechanical behavior and martensitic transformation is exhibited by wires currently on the market. Cold work and heat treatments are important variables to be controlled during the manufacture of nitinol products.

Ferritin inhibition of myelopoiesis has been associated with intrinsic ferroxidase activity of heavy-chain ferritin and with production of a monokine inhibitor of lipopolysaccharide (LPS)-augmented monocytopoiesis. We report here that intrinsic ferroxidase activity of heavy-chain ferritin is required for stimulated production of the monokine inhibitor of LPS-augmented monocytopoiesis.

The purpose of this study was to examine gingival crevicular fluid (GCF) levels of two potent bone resorbing mediators, prostaglandin E (PGE) and interleukin-1 beta (IL-1 beta), during human orthodontic tooth movement. The study included 10 patients, each having one treatment tooth undergoing orthodontic movement and a contralateral control tooth. The GCF was sampled at control sites and treatment (compression) sites before activation and a 1, 24, 48, and 168 hours. Prevention of plaque-induced inflammation allowed this study to focus on the dynamics of mechanically stimulated PGE and IL-1 beta GCF levels. The PGE and IL-1 beta levels were determined with radioimmunoassay. At 1 and 24 hours, mean GCF IL-1 beta levels were significantly elevated at treatment teeth (8.9 +/- 2.0 and 19.2 +/- 6.0 pg, respectively) compared with control teeth (2.0 +/- 1.1 pg, p = 0.0049, and 2.9 +/- 1.0 pg, p = 0.0209, respectively). The GCF levels of PGE for the treatment teeth were significantly higher at 24 and 48 hours (108.9 +/- 11.9 and 97.9 +/- 7.3 pg) than the control teeth (61.8 +/- 7.2 pg, p = 0.0071, and 70.8 +/- 7.4 pg, p = 0.0021, respectively). The GCF levels of PGE and IL-1 beta remained at baseline levels throughout the study for the control teeth, whereas significant elevations from baseline in GCF IL-1 beta (24 hours) and PGE levels (24 and 48 hours) were observed over time in the treatment teeth (p < or = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Since the initial introduction of ceramic brackets, base designs have been modified to reduce tooth damage during debonding. The purpose of this study was to compare shear and tensile bond strengths and fracture sites of four second-generation ceramic brackets: Allure IV (A) (GAC International, Inc., Central Islip, N.Y.), Ceramaflex (C) (TP Orthodontics, Inc., LaPorte, Ind.), Intrigue (I) (Lancer Orthodontics, Carlsbad, Calif.), Transcend 2000 (T) (Unitek Corp., Monrovia, Calif.), and a foil-mesh base stainless steel bracket, DynaBond II (D) (Unitek Corp., Monrovia, Calif.). Twenty brackets of each type were bonded to 100 mandibular bovine incisor teeth with Concise bonding adhesive. The samples were thermocycled for 24 hours and the brackets were debonded with an Instron universal testing machine (Instron Corp., Canton, Mass.). A modified Transcend debonding instrument was used for tensile debonding, whereas a chisel was used for shear debonding. An analysis of variance was performed with a 0.05 level of confidence. Mean shear strengths (kg/cm2) necessary to debond were 174.0 (A), 71.0 (C), 189.0 (1), 228.0 (T), and 160.0 (D). Mean tensile strengths (kg/cm2) were 27.0 (A), 26.7 (C), 51.3 (I), 56.5 (T), and 48.6 (D). Fracture sites examined with a light microscope showed no enamel damage with any of the ceramic brackets. Intrigue was the only bracket to fracture and had 30% bracket fracture in the tensile mode and 20% bracket fracture in the shear mode. The percentage of fractures at the adhesive-bracket base interface for shear and tensile modes, respectively, were 80, 100 (A); 100, 90 (C); 10, 60 (I); 60, 90 (T); and 90, 80 (D). From the data in this study, it may be concluded that (I) the ceramic brackets tested did not cause enamel damage during debonding, (2) the bracket base designs, which allow for increased adhesive thickness, decrease bond strengths, (3) the plastic wafer bases attached to ceramic brackets have adhesive-bracket base fracture sites and decreased bond strengths, (4) the wing design on ceramic brackets is a factor in bracket failure when a tensile load is applied, and (5) the tensile force is more favorable than the shear force in removing ceramic brackets.

Bacterial products such as lipopolysaccharide (LPS) and lipoarabinomannan (mycobacterial cell wall-associated glycolipid, LAM) stimulate the production of cytokines that can modulate the host response to infection. Colony-stimulating factors (CSFs) are a class of such cytokines. Not only are the CSFs produced in direct response to bacterial products or in a cytokine cascade triggered by bacterial products, but also the CSFs are lymphokines that stimulate the production and differentiation of myeloid cells from hematopoietic precursors. To date, four major CSFs are known, granulocyte–macrophage CSF (GM-CSF), granulocyte CSF (G-CSF), macrophage CSF (M-CSF), and interleukin 3 (IL-3). In addition to the role CSFs play in producing mature cells from hematopoietic precursors, they also have the dual function of activating and prolonging the survival of mature cells. The assays covered in this section provide a basis for examining the effects of bacterial products on CSF production. These assays when used alone or preferably in combination can document the presence of CSFs in a various samples. In choosing which assays are appropriate for a given situation, the specificity, number of samples, cost, and time involved in each assay must be considered. Each assay has its own advantages and disadvantages; the most notable are cost and sample range. Radioimmunoassays (RIAs) and enzyme-linked immunosorbent assays (ELISAs) are the assays of choice when test samples include preparations from tissue homogenates, as these preparations may contain by-products that are toxic to cells used in the bioassays.

This study evaluated the reliability of jaw positions, the existence of distinct jaw positions, and condyle-disk-fossa relationships in a symptom-free population by using articulator mountings and magnetic resonance imaging (MRI). The subjects examined included 28 men, 22 to 35 years of age, all having Angle Class I molar relationships and no discernible TMJ dysfunction. Records taken included the following: an axiographic face-bow to locate retruded hinge axis position, an interocclusal registration of retruded position (RE), a series of interocclusal registrations for centric occlusion (CO), a leaf gauge-generated centric relation (CR), a series of interocclusal registrations for CR, and MRI. The mandibular position indicator of the SAM articulator (Great Lakes Orthodontics, Ltd., Tonawanda, N.Y.) was used to determine reliability and existence of distinct jaw positions. Magnetic resonance imaging also evaluated jaw positions and anatomic relationships. The results indicate: (1) The articulator analysis of CO and CR is statistically replicable. (2) A distinct jaw position could be demonstrated for CO that was separate from RE and CR. It was not possible to discriminate between RE and CR. (3) Condylar concentricity was observed in half of the sample and remained consistent in RE, CO, and CR. (4) Of the sample 13% demonstrated anteriorly displaced disks that were not influenced by posterior condyle placement. (5) The clinical concept of treating to CR as a preventive measure to improve disk-to-condyle relationships was not supported by this study.

One of the reported effects of functional appliance therapy is muscular adaptation achieved through the use of vestibular shields. To develop a method for measuring these effects, 10 children with Class I molar occlusion in the late mixed-dentition stage underwent lip bumper therapy for 8 months. Semiconductor pressure transducers mounted on Tru-Tain stents in the mandibular midline and left canine areas were used to measure lip pressures with the patient at rest and during five functional exercises. Resting and speaking lip pressures for the midline transducer showed significant increases 1 month after lip bumper placement and then decreased to near or below pretreatment levels, possibly an adaptive response. Left-side resting pressures also showed a gradual decrease. In contrast, left-side speaking pressures showed no significant changes over time. The swallowing pressures were not replicable because of excessive background fluctuations. The results of this study indicate that this method has potential for improving clinical diagnosis. The preliminary data also suggest an adaptive response of lip muscles that varies according to anatomic location.

The purpose of this study was to assess the relevance of hand-wrist radiographs to craniofacial growth and clinical orthodontics. Serial annual cephalometric and hand-wrist radiographs and standing height measurements were obtained from a sample of 47 girls (ages 10 through 15 years) and 39 boys (ages 11 through 16 years) from the Bolton-Brush data base. Four skeletal linear measurements showing statistically significant increases were analyzed: SN, GoGn, SGo, and NMe. The hand-wrist radiographs were scored by the Tanner-Whitehouse TW2 RUS method of skeletal maturity assessment. The results of the study indicated that statural height and hand-wrist skeletal maturation in both sexes are significantly related. The children demonstrated a large variety of growth patterns, and growth spurts could not be consistently observed on an individual basis. Because of low statistical correlations, the relationship between acceleration and deceleration in growth of the specific craniofacial dimensions and statural height or skeletal maturity was not deemed clinically significant for prediction. However, it may be used as a factor for consideration in diagnosis and treatment planning of an individual case.

In locating condylion (Co), clinicians have used cephalograms in maximum mandibular opening to provide a clearer image of the condyle. The purpose of this study was to evaluate the accuracy of identifying condylion on a sample of open and closed mouth cephalograms of 20 patients. Five orthodontists traced each mandibular outline and located condylion and the tip of the mandibular incisor (I). The incisor tip was assumed to be relatively interpretable and served as an internal control. The differences between the open and closed positions in the horizontal and vertical components of condylion relative to the mandibular plane or in the length Co-Gn were not statistically significant. The absolute deviation around condylion was significantly different (p = 0.007), but the average absolute deviation of condylion in the open position was only 0.5 mm less than condylion in the closed position. Statistically significant differences also occurred in the means of the vertical component of the incisor tip (p = 0.002), the length Gn-I (p = 0.006), and the absolute deviation of incisor tip (p = 0.004). These results indicate that the open mouth method does not significantly change the location of condylion. It does increase the accuracy of landmark identification, but this increased accuracy on the average is not clinically significant.

Bonded acrylic orthodontic appliances are a recent alternative to banded methods. However, the physical properties demonstrated by bonding adhesives at the acrylic-enamel interphase have not been well documented. The purpose of this study was to use a laboratory testing model to evaluate the ultimate shear and tensile strengths and fracture sites of five bonding adhesives: unfilled (Bracketbond and Genie); filled (Unite, Excel, and Concise). One hundred bovine mandibular incisors were embedded in dental stone, labial surfaces ground flat for uniform acrylic-enamel adaptation, and stored in modified Fusyama's artificial saliva. Twenty 7-mm diameter acrylic cylinders were bonded in each group. Ten samples from each group were tested for shear strength and ten for tensile strength with an Instron testing machine. Bonding adhesive retained on the cylinder was measured by means of a Bioquant digitizer. Scanning electron microscopy was used to analyze fracture sites. The results showed that the percentage of bonding adhesive that remains on the acrylic surface after fracture is decreased by the addition of inorganic fillers to the adhesive and the use of separate liquid resin sealants, and is increased by the use of plastic bracket primers and bonding adhesives that are chemically similar to methylmethacrylate. Few significant differences in shear and tensile strengths were found among the bonding adhesives. Unfilled bonding adhesives cause less enamel damage and are indicated for clinical bonding of acrylic orthodontic appliances to enamel.

Infect ion control in dental and orthodontic offices has received major attention in the recent past because of increasing concern regarding the transmission of acquired immunodeficiency syndrome (AIDS) and hepatitis B virus. ~-5 Orthodontic pliers present a special problem in that they are not amenable to steam sterilization because of rusting. Dry heat sterilization requires too long a time to be practical. Unsaturated chemical vapor sterilization is practical for pliers, but

Summary Cleft palate children exhibiting maxillary segment collapse underwent orthodontic treatment with the Functional Regulator (FR). Audio and video recordings of speech were obtained periodically in conjunction with appliance management. Judges evaluated the recordings obtained with and without the FR in place by assessing speech intelligibility, resonance and nasal emission. Results indicated: a) changes in maxillary width and cross‐bite relationships were not clinically significant; b) articulation, hypernasality and nasal emission were judged to be significantly more severe during appliance wear; c) video taped speech samples were judged to be significantly less intelligible than audio taped samples; d) a substantial amount of accommodation to the FR occurred at one‐two weeks post insertion, but maximum improvement in speech intelligibility occurred over the period evaluated; and e) good speech production skills prior to orthodontic treatment minimised the adverse effect of the FR on speech intelligibility.

Nine cleft lip and palate children exhibitng collapse of maxillary segments and cross-bite were treated orthodontically with the functional regulator (FR) for periods ranging from 6 to 18 months. The purpose of this investigation was to evaluate quantitatively treatment of cleft palate patients with the functional regulator and to evaluate the effect of the appliance on their speech. Cleft palate patients typically have speech, nose, and lip defects which make patient cooperation and appliance acceptance more difficult. However, patient cooperation was considered good with an average mean of 12.7 hours per day of appliance wear and a range of 5.6 to 18.2 hours. Change in interimplant dimension was measured on frontal radiographs, and dental changes were measured of serial dental casts. The resulting data indicated no significant change in maxillary width or cross-bite relationship. The functional regulator was not clinically useful in this sample when the treatment objective was primary expansion of collapsed maxillary segments in the cleft palate patient. Good speech-production skills prior to treatment will minimize the adverse effect that the FR has on speech intelligibility. A significant amount of accommodation to the appliance occurs within 1 week after insertion, but maximum improvement in speech intelligibility occurs with full-time wear of the appliance for as many hours per day as possible.

A controlled pulsating-force system for the orthodontic movement of teeth was designed and its biologic effects were examined, with the dog serving as an experimental model. This system was applied to the maxillary right second premolar while a continuous force was delivered to the maxillary left second premolar. After a 12-day experimental period in which pulsating forces were used, the amount of tooth movement and the radiographic and histologic changes were comparable to those produced by continuous force. These preliminary data indicate that forces of greater magnitude and duration will be necessary to more fully characterize the potential advantages of a pulsating orthodontic force.

(LPS)enhance bothproduction ofcolony-stim- ulating factors (CSF)andproliferation ofmononuclear phagocytes invivo. The present study wasundertaken todetermine whether theeffects ofLPSonCSF- dependent monopoiesis areduesolely toenhanced production ofCSForalso to direct effects ofLPSontheresponding progenitor cell. Addition ofLPStoCSF- stimulated macrophage populations haddifferent effects, depending uponthe concentration ofCSFinthecultures. Inthepresence ofoptimal tosupraoptimal concentrations ofCSF,LPSatdoses 20.01jig/ml inhibited macrophage colony formation. Thisinhibitory activity wasnotduetocytotoxicity oftheLPSand wasnotmediated through prostaglandin synthesis. Inthepresence ofsuboptimal concentrations ofCSF,minute concentrations ofLPS(l0-7 tug/ml) significantly enhanced macrophage colony formation. Botheffects ofLPS(inhibition and enhancement) appeared tobeproperties oflipid Asince neither effect wasnoted withcells fromLPS-resistant C3H/HeJmice, whereas botheffects couldbe neutralized bytheaddition oftheantibiotic polymyxin B,whichbinds tothe lipid A portion ofLPS.Theseresults suggest thattheeffects ofLPSonmono- poiesis invivomaynotbeduesolely toitscapacity tostimulate production of CSF.Rather, LPSmaybeinvolved instimulating monopoiesis bothindirectly through stimulation ofCSFproduction and byitseffects ontheCSF-responsive progenitor cell. Bacterial endotoxins andtheir lipopolysac- charide (LPS) moieties actonavariety ofmam- malian cell types(reviewed inreference 3).Of these cell types, monocytes andmacrophages areperhaps themostsensitive totheeffects of LPS.Teleologically, thisisacceptable since these cells arethemostlikely toencounter either LPSorgram-negative bacteria ineither endo- toxemic orinfected animals. LPShasbeenshowntoexert a variety of