Abstract: Orthodontists have traditionally viewed structural discrepancies as the major limitation of treatment. In reality, it is the soft tissues that more closely determine therapeutic modifiability. The boundaries of dental compensation for an underlying jaw discrepancy are established by pressures exerted on the teeth by the lips, cheeks, and tongue; limitations of the periodontal attachment; neuromuscular influences on mandibular position; and the contours of the soft tissue facial mask. The ability of the soft tissues to adapt to changes in tooth-jaw relationships are far narrower than the anatomic limits in correcting occlusal relationships. The tolerances for soft tissue adaptation from equilibrium, periodontal, and facial balance standpoints are in the range of 2 to 3 mm for expansion of the mandibular arch and even less for changes in condylar position. Thus, analysis of the soft tissues is the critical step in orthodontic decision making, and this can only be accomplished through physical examination of the patient. Although quantitative measurements cannot be rigorously applied, guidelines for soft tissue assessment, with particular emphasis on facial esthetics, are proposed. From this perspective, a contemporary philosophy of orthodontic practice is offered, with general indications and contraindications for nonextraction, extraction, and surgical treatment.

Abstract: The majority of rapid maxillary expansion studies have reported the use of appliances with metal bands attached to the posterior teeth. Tooth extrusion, dental tipping, and an increase in the vertical dimension are often encountered, which may not coincide with treatment objectives. Bonded appliances using interocclusal acrylic may control the vertical dimension and expand the maxillary halves in a more bodily and symmetrical fashion. The purpose of this clinical trial was to determine, by radiographic analysis, the differences between a conventional banded expander (Hyrax) and a bonded acrylic expander. Fourteen patients who exhibited a need for expansion were enrolled in the study. The results suggest that the increase in the vertical dimension often seen with the more conventional Hyrax appliance may be minimized or negated with the bonded appliance. However, there appeared to be no significant difference between the amount of dental tipping or symmetrical expansion between the two appliances, as previously theorized.

Abstract: Orthodontic patients have reported the use of analgesics during therapy. However, common anti-inflammatory analgesics, such as aspirin and ibuprofen, have been shown to slow the rate of tooth movement. Acetaminophen, another common analgesic, does not possess anti-inflammatory properties. The effect of acetaminophen on tooth movement was studied using New Zealand white rabbits. Experimental animals were matched to a control animal of the same sex and weight. Under anesthesia, springs were ligated between the lower first molar and incisor, resulting in approximation of these teeth. Under blinded conditions, seven of the rabbits received 1000 mgs of acetaminophen daily. Seven control animals received water. The animals were sacrificed after 21 days. The movement of incisors and molars was measured. Results showed considerable movement within both the experimental and control groups, but no significant difference in tooth movement between them. Acetaminophen has no effect on the rate of tooth movement in rabbits undergoing orthodontic treatment.

Abstract: A resin-reinforced glass ionomer cement, distributed commercially as “Fuji Ortho” (FO), has recently been developed for orthodontic bracket bonding procedures. The purposes of this study were to determine the tensile and shear bond strength of FO, to measure the amount of cement remaining on the enamel after bracket removal, and to evaluate the effects of experimental strain on the enamel surface. SEM evaluation demonstrated that polishing with 2400-grit waterproof abrasive paper followed by treatment with polyacrylic acid produced a smooth enamel surface without debris. No significant differences were seen in bond strengths between 24 hours and thermal cycling. Tensile and shear strengths of FO were significantly higher after thermal cycling than with conventional glass ionomer cement, at 3.4±0.7 MPa and 17.9±4.5 MPa, respectively. The Adhesive Remant Index (ARI) indicated that FO adhered firmly to the unetched enamel surface and its scores showed 2 to 3 after thermal cycling. Results of this in...

Abstract: The specific contribution of enlarged tonsils or adenoids to craniofacial growth remains unknown, and there is no agreement in the literature as to the significance of lip posture. This study assessed the separate associations of lip posture, sagittal airway size, and tonsil size with selected cephalometric measures. Clinical and cephalometric data of 207 children who presented for evaluation of tonsil and/or adenoid problems were evaluated. Multiple linear regression was used to assess the linear relationship between each of the three parameters and the cephalometric dependent variables. Open lip posture, reduced sagittal airway, and large tonsils were each associated statistically with a characteristic but different skeletal configuration. This association was proportional. Specifically, a more open lip posture was associated with a more backwardly rotated face and larger lower facial height. Reduced sagittal airway size was associated with en bloc backward relocation of the maxilla and mandible. Because the sella-nasion dimension shortened proportionally, the SNA and SNB angles were not affected. Larger tonsils were associated with more forward relocation and rotation of the maxilla and mandible and increased SNA and SNB angles. Because each of the three parameters was associated proportionally with a different craniofacial morphology, it is concluded that lip posture, sagittal airway size, and tonsil size represent three different and unrelated phenomena with respect to their effects on craniofacial growth and form.

Abstract: Orthodontic treatment outcome is often compromised by the loss of anchorage. The forces acting on the anchorage unit have, however received surprisingly little attention, and the loss of anchorage is most frequently expressed in the sagittal occlusal relationship. The present paper discusses the interaction between vertical and sagittal components of dentofacial development, and the importance of taking vertical forces into consideration is stressed. The biological background for anchorage is reviewed, i.e., the impact on the cellular reaction of the periodontal ligament around the teeth of the anchorage unit from the orthodontic force system and from occlusion. A new rigid appliance consisting of two occlusal splints connected with transpalatal arches is introduced. The advantage of using the patient's sense of occlusion as part of anchorage by means of this appliance is demonstrated in a number of case presentations.

Abstract: Treatment of horizontal and vertical tooth discrepancies requires wires of low stiffness to produce forces as the teeth are leveled and aligned. In this investigation, the stiffness characteristics of several solid and multistrand nickel-titanium and stainless steel orthodontic wires were determined at selected clinically relevant deflections. Twenty specimens of 24 different wires were tested in both three-point and three-bracket bending modes. The unloading force deflection plot of each wire was described by a polynomial regression from which wire stiffnesses were obtained by mathematical differentiation. Graphs of the functional relationship between stiffness and deflection are presented. The results of this investigation show that wire stiffness can be altered not only by changing the size, but also by varying the number of strands and the alloy composition. An equally important finding was the dependence of stiffness on deflection for most of the wires measured. Comparisons were also made be...

Abstract: This retrospective Herbst study analyzes and compares the sagittal dental and skeletal effects contributing to Class II correction in subjects with small or large pretreatment mandibular plane angles. Lateral headfilms of 15 hypodivergent (ML/NSL 39 degrees) Class II subjects treated to a Class I occlusal relationship with the Herbst appliance were analyzed. Radiographs were taken before and after an average treatment period of 7 months. Cephalograms were evaluated according to the method of Pancherz. In both groups, impprovements in sagittal incisor and molar relationships were achieved by greater dental than skeletal changes. The amount of skeletal changes contributing to overjet and molar correction was larger in the hyperdivergent group (37% and 44%, respectively) than in the hypodivergent group (25% and 25%, respectively). Dental and skeletal changes contributing to Class II correction were found to be independent of the vertical jaw base relationship. Thus, a hyperdivergent jaw base relationship did not affect the treatment response unfavorably.

Abstract: The purpose of this project was to use finite element modeling to calculate and compare the peak stresses generated during clinical debonding of resin bonded brackets. Five debonding techniques were considered: tension, shear-peel, torsion loads on the bracket, wedging of the cement margin, and bracket temperature increase. The data is presented in terms of the relative potentials of the methods for causing enamel fracture. That is, in this idealized model, it was assumed that enamel failures were governed by maximum principal or shear stress. Therefore, all debonding loads and calculated stresses were scaled to correspond to unit peak principal stress or unit peak shear stress in enamel. Furthermore, it was assumed that cement cohesive failure was also governed by maximum principal or maximum shear stress and that adhesive failures were caused by interface normal or shear stress. Thus, for example, it was found that for 1.0 MPa of peak shear stress in enamel, tension and shear-peel debonding generate, respectively, 1.34 and 0.96 MPa of peak normal (tensile) stress in the cement at the enamel-cement interface. The interpretation of this information is that tension debonding is less likely to cause enamel damage than shear-peel loading if it is assumed that (1) the enamel would fail due to the high shear stress, and (2) the joint would fail at the enamel-cement interface because its normal stress limit has been exceeded.

Abstract: Cephalometric radiography is an important diagnostic aid in orthodontics. Mesh analysis is a proportionate cephalometric method of graphically assessing disharmonies of the craniofacial complex. Original norms for this analysis were created from a white, European American sample. Norms for black Americans of African descent were developed in another study. The purposes of this investigation were: (1) to develop a standard mesh diagram from a Puerto Rican American population; (2) to compare the diagram with previously established data from the white sample; (3) to develop linear and angular means for the Legan, Burstone, Ricketts, DiPaolo, and Steiner analyses for a Puerto Rican American population; and (4) to assess the use of a panel for selecting esthetically pleasing faces. The subjects in the study had no previous orthodontic treatment, had Class I occlusion with 6 mm or less of crowding per dental arch, and had two parents and two sets of grandparents who were were born in Puerto Rico. Sixty-nine patients met the study criteria, and 50 of those patients (20 males and 30 females) were selected as having esthetically pleasing faces by the panel. Male and female norm diagrams were created and these were compared with those developed previously. Linear and angular measurements were also compared. Significant differences between the ethnic groups were found in the dentoalveolar region. Similarities were noticed in the upper face height and anterior cranial base length. The panel selection results showed no agreement within the sexes, occupations, or ethnic groups.

Abstract: The purpose of this study was to document soft tissue profile changes in late adolescent skeletal Class I males from 14 to 20 years of age and to compare these changes with those of the un...

Abstract: The purpose of this study was to determine whether the application of chlorhexidine to etched enamel affects the shear bond strength and bracket/adhesive failure modes of orthodontic brackets. Forty recently extracted third molars were cleaned divided into two groups of twenty. The first group was etched with a 37% phosphoric acid gel, and a sealant was applied containing a chlorhexidine varnish. Stainless steel orthodontic brackets were bonded using the Transbond XT bonding system (3M/Unitek). Teeth in the second group were etched and bonded using the same bonding system but without chlorhexidine. A Zwick Universal Testing Machine was used to determine shear bond strengths. There were no significant differences in bond strengths between the chlorhexidine treated teeth (= 11.8 +/- 2.1 MPa) and the controls (= 12.4 +/- 3.1 MPa) (p = 0.129). The Chi Square test evaluating the residual adhesive on the enamel surfaces showed no significant differences (P = 0.136) between the two groups evaluated. The use of a primer containing chlorhexidine does not significantly affect shear bond strength nor the fracture site (bond failure location).

Abstract: A simple method for magnification correction of width measurements from posteroanterior (PA) cephalograms is presented. Small lead markers were placed on selected landmarks of dry skulls. Lateral and PA cephalograms were obtained for each skull. Seven cephalometric width measurements were selected. Actual widths were deduced from the geometric principle of similar triangles. The magnification factor is the distance between the anode and the transporionic axis, plus or minus the corrected distance of the landmark to the transporionic axis measured from the lateral cephalogram, divided by the distances between the anode and the film. Differences between measurements made directly on the skull and corrected width measurements from the PA films were observed to be very small ( 0.05). Paired measurements were of high correlation (r=+0.99). The present method of magnification correction means cephalometric width measurements can be made that are comparable in...

Abstract: The Jasper Jumper appliance provides a method of Class II correction with an active force component that the patient cannot remove. A modification of classic Jasper Jumper usage is illustr...

Abstract: The purpose of this retrospective study was to investigate the accuracy of two video imaging systems, Orthognathic Treatment Planner (OTP) and Prescription Portrait (Portrait), in predicting soft tissue profile changes after maxillary impaction surgery. Computer-generated line drawing predictions were compared with actual postsurgical profiles. Neither program was very accurate with vertical measures and lower lip contour. Portrait was more accurate at pronasale, inferior labial sulcus, and pogonion in the y-axis direction (P < 0.05). Video image predictions produced from the presurgical photographs were rated by orthodontists, surgeons, and lay people, who compared the predictions with the actual postsurgical photographs using a visual analog scale. Portrait's prediction images were scored higher than OTP's for five of eight areas. Orthodontists were most critical of the lips and the overall appearance. Lay people were most critical of the chin and submental areas.

Abstract: The purpose of this study was to compare the Ceramaflex bracket with a traditional ceramic orthodontic bracket with regard to shear bond strength and bond failure location. Forty newly extracted human premolars were randomly divided into two groups. Twenty Ceramaflex brackets (TP Orthodontics Inc, LaPorte, Ind) and 20 Transcend 6000 brackets (Unitek Corp, Monrovia, Calif) were bonded to the teeth using the same bonding system (Right On, TP Orthodontics Inc, LaPorte, Ind). A Zwick Universal Test machine (Zwick Gm bH & Co, Ulm, Germany) was used to determine the shear bond strength for each bracket. After debonding, the teeth and brackets were examined under 10x magnification. After debonding, the amount of resin material adhering to the enamel surface was assessed according to the Adhesive Remnant Index (ARI). The results of this study suggest that Ceramaflex brackets have a significantly lower bond strength than traditional ceramic brackets. On the other hand, the bond failure location of the Ceramaflex bracket was consistently more favorable, i.e., occurring at the ceramic bracket-polycarbonate base.

Abstract: The mesh analysis is a proportionate cephalometric analysis that enables a patient to serve as his or her own control to create a template from which to assess skeletal, dental, and craniofacial disharmonies. The norms for this analysis were originally created from a white, European American sample. The purposes of this study were: (1) to create a normal mesh diagram from a black, African American population; (2) to compare mesh diagrams from black and white Americans; and (3) to evaluate the usefulness of a panel of diverse members in selecting subjects. All subjects were black Americans of African descent, had no prior orthodontic treatment, and had Class I dental occlusion with minimal crowding (4 mm or less). The panel selected as esthetically pleasing 18 males and 25 females from a group of 77 patients meeting the study criteria. Male and female normal mesh diagrams were created from the cephalographs and compared with Caucasian normal diagrams developed by Moorrees in 1976. Linear and angular components of the hard and soft tissues were compared. Comparisons were also made with previously published normal values. Differences between the African American and Caucasian samples were more notable close to the dentoalveolar complex. Similarities were limited to the soft tissue of the upper face, the cranial base, and the midface. Analysis of the panel selection results did not suggest any trends between or within race, sex, or occupation of the panel members. However, agreement between the races was good.

Abstract: Protraction headgear has been used in conjunction with a palatal expansion appliance to correct Class III malocclusion with maxillary deficiency and/or mandibular prognathism. In general, ...

Abstract: Midface retrusion in cleft lip and palate patients often results in personal, social, and psychological problems, along with the functional difficulty. Hence, soft tissue profile improvement in early childhood is of obvious importance. The purpose of this study was to investigate the soft tissue changes that occur during reverse headgear treatment in a homogeneous sample of Chinese boys born with unilateral complete cleft lip and palate. Boys with a similar congenital deformity and presenting similar skeletal morphology and maturity status were included for comparison. After 7.8 months of reverse headgear treatment, the soft tissue profile improved significantly as the concave tendency associated with maxillary deficiency decreased. The sagittal maxillomandibular lip relationship and the Holdaway angle increased significantly by 4.25 and 3.94 degrees, respectively.

Abstract: This retrospective study was undertaken to describe and compare frontal craniofacial dimensions in alveolar-bone-grafted and nongrafted complete unilateral cleft lip and palate (CUCLP) patients and in noncleft subjects with normal occlusions and good facial balance. Clinical data were obtained from the files of the Hospital for Sick Children, Toronto. Patients were eligible for inclusion if they had posteroanterior cephalograms (PA) taken at adulthood and no congenital anomalies other than CUCLP. A total of 86 adult Caucasian CULCP patients were studied, including 58 who had not received grafts, 28 who had received secondary alveolar bone grafts, and, for comparison, 60 noncleft Caucasian adults. The PA cephalometric radiographs were traced, digitized, and measured. Analysis of variance (ANOVA) was used to test for among-groups differences in the means of the ratios, proportions, and angular measures. Tukey-Kramer HSD procedure was used to conduct post-hoc pairwise comparisons following significant (p < or = 0.05) F-ratios from ANOVA. Sexual dimorphism was a common finding, with males demonstrating greater facial width. Despite primary surgical repairs, the anterior nasal spine in the nongrafted CUCLP patients was deviated to the noncleft side, and the alar base was depressed on the cleft side. The maxillary incisors close to the cleft site were irregularly inclined, and this irregularity was more severe in the nongrafted CUCLP patients. The long-term effects of secondary alveolar bone grafting on transverse craniofacial growth appears to be minimal and limited to the immediate area of the cleft.

Abstract: Cherubism is a rare, fibro-osseous bone disease that affects the jaws. Bilateral enlargement of the mandible produces a full, round lower face. The skin over the cheeks stretches and pulls...

Abstract: The patient showed bilateral agenesis of the mandibular condyle and glenoid fossa, rare features of hemifacial microsomia. The patient was treated with functional appliances to modify mandibular growth during active facial growth. After the pubertal growth spurt, treatment included rotational advancement of the mandible combined with alloplastic reconstruction of the condylar process and glenoid fossa.

Abstract: Proximal alveolar bone level changes were radiographically determined in 20 subjects (mean age 14.3 years, SD 2.00) a short time after rapid orthodontic treatment with magnets and superelastic nickel-titanium coils succeeded by straight-wire appliances. The findings were compared with a matched control group of 20 individuals (mean age 14.3 years, SD 1.99) who had no history of orthodontic treatment. Proximal alveolar bone level changes were determined on bitewing radiographs as the distance between the cementoenamel junction (CEJ) and the alveolar bone crest (AC). The observation period was 2.7 years (SD 0.65) for the treatment group and 2.8 years (SD 0.65) for the control group. In the treatment group, a small mean increase of 0.2 mm (SD 0.29) in the CEJ-AC distance was found a short time after treatment. In the control group the increase in CEJ-AC distance was 0.1 mm. The difference between the groups was significant (P < 0.001). In the treatment group, sites in the maxilla showed significantly greater CEJ-AC distances than in the mandible (P < 0.001), 0.3 mm (SD 0.33) versus 0.1 mm (SD 0.24). The mesial sites of the maxillary first molars in the treatment group showed the highest average increase in distance between CEJ and AC, mean 0.5 mm (SD 0.33). Neither group had any sites with bone loss, i.e., CEJ-AC distance exceeding 2 mm. No significant difference was found in CEJ-AC distance between teeth moved with magnets succeeded by straight-wire appliances and teeth moved with superelastic coils succeeded by straight-wire appliances.

Abstract: Some patients who have an anterior crossbite in the deciduous dentition lose the crossbite during the transitional stage to permanent anterior teeth without orthodontic and/or orthopedic treatment. We observed 220 anterior crossbite patients at regular intervals and identified three groups of patients: in group N (n = 16) the crossbite corrected when the central incisors erupted; in group R1 (n = 16) the crossbite was within [formula: see text] and remained unchanged following the eruption of the permanent central incisors; in group R2 (n = 12) the crossbite extended over [formula: see text] and remained following the eruption of the permanent central incisors. The purpose of this study was to determine whether any differences existed among the above three groups at the initial examination, or if differences arose during eruption of the teeth. The findings indicate that the mandibular position in group N was more posterior than in groups R1 and R2, and the lengths of Pog'-Go and Gn-Cd in group N were smaller. Tooth axis of the lower incisors in groups R1 and R2 showed lingual tipping, and the maxilla in group R2 was underdeveloped. The findings of the longitudinal changes indicated that the maxillary length in group N increased and mandibular forward growth was suppressed. The initial maxillary position in groups R1 and R2 remained much the same until the permanent central incisors erupted.

Abstract: The purpose of this study was to quantify the amount of alveolar modeling at the apices of the mandibular incisor and first molar specifically associated with appositional and resorptive c...

Abstract: Adlloy surface treatment of noble alloys has been shown to increase the bond strength of composite to gold alloys. The purpose of this study was to test the bond strength of Adlloy-treated type IV gold surfaces and orthodontic brackets bonded with self-curing composite resin, and compare it with sandblasted gold and etched enamel. Data were derived from a control sample of 40 human premolars and two experimental groups of Adlloy-treated and sandblasted gold surfaces. “A”-Company premolar brackets were bonded with Concise self-curing composite resin. The specimens were submerged in water for 30 days and thermocycled 1500 times before being subjected to shear bond tests. Statistically significant differences were found in the mean values of the three groups (F=l24.04; df=2, 117; P<.001). Bonds on the Adlloy-treated gold were twice as strong as those found on microetched gold. Adlloy surface treatment of type IV gold will permit adequate bond strength; however, FDA approval is required for intraoral...