Seminars in Orthodontics

Published by WB Saunders
Online ISSN: 1073-8746
Publications
Article
The Bioprogressive orthodontic treatment philosophy is traditionally associated with the use of brackets that have .018" slots. Proponents of the Bioprogressive philosophy suggest this slot configuration largely because they believe that lighter wires provide force levels that are within the biological limits of the periodontal support system. At the same time, the principles of orthodontic anchorage advocated by the Bioprogressive philosophy depend on careful torque control of both molar and anterior teeth. It is possible and sometimes advisable to use wires designed for use in brackets with .018" slots, in brackets with .022" slots. Under these circumstances, the thinner wires may not provide sufficient control over torque moments to develop the required degree of molar anchorage. This article suggests that with the use of certain wires, and with minor modifications to the shapes of arches, that the use of brackets with .022" slots need not conflict with many of the important principles of orthodontic treatment advocated in the Bioprogressive philosophy.
 
Article
The optimum age for surgical closure of cleft palate remains an unresolved question, despite the fact that many clinicians have studied the issue since the 1930s. This article reviews the debate as it has taken shape over the last several decades, with a prospective view toward how standards of practice may evolve in the foreseeable future.
 
Article
This paper outlines the clinical application of cone beam computed tomography (CBCT) for the assessment of treatment outcomes and discusses current work to superimpose digital dental models and 3-dimensinal photographs. Superimposition of CBCTs on stable structures of reference now allow assessment of 3-dimensional dental, skeletal, and soft-tissue changes for both growing and nongrowing patients. In addition, we describe clinical findings from CBCT superimpositions in assessment of surgery and skeletal anchorage treatment.
 
Article
In the course of orthodontic practice, it is inevitable that one will encounter what is termed here eruptive abnormalities. These abnormalities include teeth that are impacted, ectopically erupting, or transposed. Hyperdontia and hypodontia are also included for consideration. The treatment plans developed to address these anomalies must take into account the space needs of the patient and how one can best gain, maintain, or redistribute that space. Also, soft tissue reactions to the movements also should be considered.
 
Article
During the initial examination of a patient, the orthodontist may encounter various findings that will, for the most part, be normal or variants of normal. Most pathological conditions encountered will be derived from structures normally found in the anatomic locations examined. Knowledge of the anatomy and common pathological entities based on location can prove helpful when abnormalities are encountered. This article describes anatomic locations and their contents in and around the oral cavity and discusses pathological processes commonly encountered in these locations. Syndromes involved with various abnormalities also are briefly mentioned. The intent of this article is to give the clinician a working knowledge of commonly occurring pathological entities.
 
Article
Partially bracketed arch wires can be activated in the transverse dimension to produce first-order rotations of the molars and constriction or expansion of intermolar width. A 2 x 6 arch wire is ideal for such activations because of the minimal side effects to the anterior teeth. As with other two-couple orthodontic appliance systems, symmetrical V-bends, asymmetrical V-bends and step bends are used to generate moments of the couples whose associated equilibrium forces can be used to produce desired tooth movement.
 
Article
This study presents the findings of 162 patients who underwent rapid maxillary expansion during the early mixed dentition. Maxillary changes were evaluated through the analysis of serial dental casts. Arch dimensions were measured pre-expansion, immediately post-expansion, and at yearly intervals until the eruption of the first premolars. The expansion was effected with an acrylic rapid maxillary expansion appliance bonded to the posterior teeth for 5 to 6 months. A simple retention protocol was used post-expansion. The average increase in transpalatal width was 5 to 6 mm. During the post-expansion period, most of the arch width increases were maintained. For example, 90.5% of the original expansion at the first permanent molars remained after the first year, with slightly less overall expansion (80.4%) evident at the end of the observation period (2.4 years postexpansion). Maxillary dental arches that initially were narrow tended to retain a greater percentage of the achieved expansion than those with initially wider arch dimensions. In addition, maxillae with initially more lingually-inclined molars tended to retain more expansion than maxillae with initially more facially-inclined molars. Palatal vault height decreased very slightly during treatment, but returned to pretreatment values one year after expansion and increased slightly during subsequent time intervals. The results of this study indicate that the majority of increased arch dimensions in patients produced by early orthopedic expansion of the maxilla are maintained at the end of the transitional dentition.
 
Article
This article outlines the authors' research findings on the craniofacial growth of untreated skeletal Class III malocclusion, as well as the short-term and long-term effects of chincap orthopedic force for controlling Class III mandibular growth. Skeletal Class III malocclusion is believed to be the result of excessive growth of the mandible with respect to the maxilla and/or cranial base. The results of the authors' longitudinal studies show similar maxillary and mandibular incremental growth change during prepubertal, pubertal, and postpubertal periods when compared with Class I subjects. Therefore, it seems reasonable to assume that the skeletal framework of the Class III malocclusion must have been established before the prepubertal growth period. As for treatment with chincap appliances, the study on short-term and long-term effects indicate that, on average, the skeletal profile is greatly improved during the initial stages of chincap therapy. However, such changes are rarely maintained during pubertal growth period. Treatment with chincap appliances seldom alters the inherited prognathic characteristics of skeletal Class III profiles after completion of growth.
 
Article
The purpose of this article is to summarize the short-term and long-term results of the authors' clinical prospective study on the treatment of Class III malocclusion using the protraction facemask. An attempt is made to answer questions pertaining to this treatment modality. Twenty patients with skeletal Class III malocclusion were treated consecutively with maxillary expansion and a protraction facemask. A positive overjet was obtained in all cases after 6 to 9 months of treatment. These changes were contributed to by a forward movement of the maxilla, backward and downward rotation of the mandible, proclination of the maxillary incisors, and retroclination of the mandibular incisors. The molar relationship was overcorrected to Class I or Class II dental arch relationship. The overbite was reduced with a significant increase in lower facial height. The treatment was found to be stable 2 years after removal of the appliances. At the end of the 4-year observation period, 15 of the 20 patients maintained a positive overjet or an end-to-end incisal relationship. Patients who reverted back to a negative overjet were found to have excess horizontal mandibular growth that was not compensated by proclination of the maxillary incisors. A review of the literature showed that maxillary expansion in conjunction with protraction produced greater forward movement of the maxilla. Maxillary protraction with a 30 degrees forward and downward force applied at the canine region produced an acceptable clinical response. The reciprocal force from maxillary protraction transmitted to the temporomandibular joint did not increase masticatory muscle pain or activity. Significant soft tissue profile change can be expected with maxillary protraction including straightening of the facial profile and better lip competence and posture. However, one should anticipate individual variations in treatment response and subsequent growth changes. Treatment with the protraction facemask is most effective in Class III patients with a retrusive maxilla and a hypodivergent growth pattern. Treatment initiated at the time of initial eruption of the upper central incisors helps to maintain the anterior occlusion after treatment.
 
Article
The purpose of this article is to summarize the existing scientific data with respect to the short- and long-term effects of the Herbst appliance on the occlusion and on the maxillo/mandibular complex. The article also discusses the treatment indications and possible treatment limitations. The Herbst method is most effective in the treatment of Class II malocclusions. Long-term stability seems to be dependent on a stable cuspal interdigitation. Marked mandibular morphological changes occur during therapy and sagittal condylar growth is increased. Posttreatment, most of the mandibular morphological changes revert and no long-term influence of Herbst treatment on mandibular growth can be verified. The appliance effect on the maxillary complex can be compared with that of a high-pull headgear. Without proper retention, however, this effect is of a temporary nature. Herbst treatment is especially indicated in the permanent dentition at or just after the pubertal peak of growth. Mixed dentition treatment is not recommended, as a stable cuspal interdigitation after therapy is difficult to achieve and relapses are prone to occur. In the nongrowing patient, the appliance should be used with great caution.
 
Article
For more than 40 years, research in the Department of Orthodontics, University of Washington (Seattle, WA) has focused on a growing collection of more than 800 sets of patient records to assess stability and relapse of orthodontic treatment. All patients had completed treatment a decade or more before the last set of data. Evaluation of treated premolar extraction patients, treated lower incisor extraction patients, treated non-extraction cases with generalized spacing, patients treated with arch enlargement strategies, and untreated normals showed similar physiologic changes: (1) Arch length decreases after orthodontic treatment. (2) Arch width measured across the mandibular canine teeth typically reduces posttreatment, whether or not the case was expanded during treatment. (3) Mandibular anterior crowding during the posttreatment phase is a continuing phenomenon well into the 20-to-40 years age bracket and likely beyond. (4) Third molar absence or presence, impacted or fully erupted, seems to have little effect on the occurrence or degree of relapse. (5) The degree of post-retention anterior crowding is both unpredictable and variable and no pretreatment variables either from clinical findings, casts, or cephalometric radiographs before or after treatment seem to be useful predictors.
 
Article
Patients whose vertical discrepancies are best corrected with both orthodontics and surgery can be placed into two distinct categories. The first category is the group of patients who have short posterior facial heights in conjunction with excessive anterior facial heights. The second category is the group of patients who have the opposite problem, i.e., excessive posterior facial heights and decreased anterior facial heights. Both of these types of malocclusions can best be treated with a combination of orthodontics and surgery. Alternative treatment for these "outer limits" patients require a thorough differential diagnosis, selection of appropriate force systems, and an understanding that nonsurgical treatment will result in compromises. Although these compromises must be accepted these patients can expect treatment results that are esthetically pleasing, highly acceptable for the teeth and supporting tissues, functional, and reasonably stable if a careful differential diagnosis is followed with treatment that uses precise space management with sequential directional force application.
 
Article
Seventy-five percent of all cleft lip and palate patients have osseous defects of the alveolus. Bone grafting of this defect normalizes facial and dental function. Failure to reconstruct the osseous deformity may result in oronasal fistula, fluid reflux, speech pathology, anteroposterior deficiency of the maxilla, transverse deficiency of the maxilla, lack of bone support for the incisors and cuspids, dental crowding, and facial asymmetry. Bone grafting unifies the maxilla and is best done after the majority of facial growth is complete and the secondary dentition is erupting. This is known as secondary bone grafting and yields the best results. The dentofacial deformity of cleft lip and palate is best managed by coordination of dental development, surgery and orthodontics.
 
Article
Experimental animal studies have shown that orthodontic movement of teeth into infrabony pockets may be detrimental to the periodontal attachment. After elimination of subgingival plaque infection in the experimental animals, no additional loss of connective tissue attachment occurred. An experimental model has shown that a tooth with normal periodontal support can be orthodontically moved into an area of reduced bone height with maintenance of height of connective tissue attachment level and alveolar bone support. The results from these experimental studies have been tested clinically.
 
Article
Courts routinely award coverage for TMJ disorders under medical plans, despite exclusionary language and evidence that the insured failed to disclose preexisting treatment as required by the plan and neglected to attempt more conservative treatment first. Such decisions adversely affect both the health carrier and the plan participants. Various states have enacted legislation mandating coverage of TMJ; however, TMJ issues still exist and will remain a frequent topic for litigation until the judiciary recognizes that validating contract language ultimately benefits insureds as consumers and reinforces the integrity of the industry as a whole.
 
Article
Orthognathic surgery has made many advances since its inception. This, combined with modern day health economics, has necessitated changes in orthognathic surgical practice. The bilateral sagittal split osteotomy is evaluated as an ambulatory surgical procedure. Studies have proven the sagittal split osteotomy can be performed as an ambulatory procedure. Patient costs, as well as other issues that impact on the patient and health care provider, are reviewed. The need for additional outcome data to determine whether patient care or perception of care is affected is discussed.
 
Article
Today implants are commonly used to replace missing teeth in partially edentulous adult orthodontic patients. Because these patients are missing teeth, orthodontic mechanics may be complicated or often impossible because of insufficient anchorage. In these situations, it may be feasible to use the implant initially as an orthodontic anchor to facilitate complex tooth movement and secondarily as an abutment for a crown or fixed prosthesis. This article will discuss the ramifications and requirements for using implants as anchors and abutments in adult orthodontic patients.
 
Article
When two successive couples are present, the absolute value of the moment at each bracket cannot be clinically determined. The larger moment can be identified, however, and this will show the direction of the associated equilibrium forces. If the couples at two adjacent brackets produce moments in opposite directions, the associated equilibrium forces are also in opposite directions. The net equilibrium force present at each bracket is in the direction of the equilibrium force associated with the larger moment, but the magnitude of the force is reduced by the oppositely directed equilibrium force associated with the lesser moment. If the couples at two adjacent brackets produce moments in the same direction, their associated equilibrium forces are also in the same direction and the net equilibrium force present at each bracket is the sum of the equilibrium force associated with each moment.
 
Article
This paper describes the protocols used at Childrens Hospital Los Angeles (CHLA) to protract the maxilla during early adolescence. It is a modification of techniques introduced by Eric Liou with his Alternate Rapid Maxillary Expansion and Constriction (ALT-RAMEC) technique. The main differences between the CHLA protocol and previous maxillary protraction protocols are the age the protraction is attempted, the sutural loosening by alternating weekly expansion with constriction and the use of Class III elastics to support and redirect the protraction by nightly facemask wear. The CHLA protocol entirely depends on patient compliance and must be carefully taught and monitored. In a cooperative patient, the technique can correct a Class III malocclusion that previously would have been treated with LeFort 1 maxillary advancement surgery. Thus, it is not appropriate for patients requiring 2 jaw surgeries to correct mandibular prognathism, occlusal cants or facial asymmetry. The maxillary protraction appears to work by a combination of skeletal advancement, dental compensation and rotation of the occlusal planes. Microscrew/microimplant/temporary anchorage devices have been used with these maxillary protraction protocols to assist in expanding the maxilla, increasing skeletal anchorage during protraction, limiting dental compensations and reducing skeletal relapse.
 
Article
Because of the wide variation found in Class II malocclusions, many different diagnostic decisions must be made. Treatment mechanics must, of necessity, differ. This case report describes the treatment of a Class II malocclusion which, for correction, required the extraction of maxillary first premolars and mandibular second premolars.
 
Article
Orthodontists need to know the effectiveness, efficiency and predictability of treatment approaches and methods, which can be learned only by carefully studying and evaluating treatment outcomes. The best data for outcomes come from randomized clinical trials (RCTs), but retrospective data can provide satisfactory evidence if the subjects were a well-defined patient group, all the patients were accounted for, and the percentages of patients with various possible outcomes are presented along with measures of the central tendency and variation. Meta-analysis of multiple RCTs done in a similar way and systematic reviews of the literature can strengthen clinically-useful evidence, but reviews that are too broadly based are more likely to blur than clarify the information clinicians need. Reviews that are tightly focused on seeking the answer to specific clinical questions and evaluating the quality of the evidence available to answer the question are much more likely to provide clinically useful data.
 
Article
The open bite malocclusion has been described as being of 2 types: dental and skeletal. Proper differentiation is essential in determining the appropriate corrective measures. Dental open bites are generally more responsive to treatment with orthodontics alone, whereas skeletal open bites often require a combination of orthodontics and orthognathic surgery. Patient selection and treatment principles for nonsurgical open bite treatment are discussed, and a review of various methods of treatment for the skeletal open bite is presented. Posttreatment stability and retention concerns are addressed.
 
Article
The purpose of this study was to evaluate the skeletal and dentoalveolar changes occurring during two-phase orthodontic treatment. A cephalometric study of Class II correction was carried out in 40 subjects (20 females, 20 males) who had been treated with the acrylic-splint Herbst appliance immediately followed by a second phase of preadjusted edgewise therapy. The average age at the start of Herbst therapy was 12.5 +/- 0.8 years for females and 13.6 +/- 1.2 years for males. Descriptive cephalometric data were compared with the normative values derived from the University of Michigan Elementary and Secondary School Growth Study. Control values were generated for each of the 40 Herbst patients based on gender, initial age, and duration of treatment. The results of this study indicate that the Class II correction achieved during Phase I treatment with Herbst appliance was due mainly to an increase in mandibular length, as well as distal movement of the maxillary molars and mesial movement of the mandibular molars and incisors. The accelerated mandibular growth rate observed during Herbst therapy was followed by a diminished growth rate during the edgewise phase that was less than control values. The overall increase in mandibular length was slight (approximately 1 mm), but significantly greater than control data for the whole group and the male subgroup; however, it was not significantly different between the treatment group and control data in the female subgroup. There were no significant treatment effects on lower anterior facial height and the mandibular plane angle at the end of either phase of treatment. The skeletal changes contributed to 55% of the molar correction during the Herbst therapy, whereas at the end of the second phase of treatment, skeletal change accounted for 80%. Significant anteroposterior dentoalveolar rebound was seen during the edgewise phase.
 
Article
Since the early 20th century, functional appliance therapy has been a significant part of orthodontic treatment, especially in Europe, where functional appliances have been used to treat many malocclusions, including some skeletal discrepancies. Although the success of functional appliance therapy as reported in numerous short-term studies from 1930 to 1975 led to an euphoric acceptance of this method, the few long-term studies, especially those comparing treated with untreated homogeneous control groups, indicated that the specific skeletal and dentoalveolar effects depended on the individual growth period and pattern of the patient. In this article, a specific functional appliance, the Bionator, is presented. Long-term follow-up studies provide indications for its use. At the present time, functional orthopedic appliance therapy has a more limited but well-defined place in our therapeutic approach. The type and character of the malocclusion determines the indications and contraindications of the functional appliance. Scientific and clinical experience has shown the importance of a differential diagnosis for each patient, which integrates etiology and morphogenesis in the individual treatment objectives for special skeletal, dentoalveolar, and functional regions. Individualization in the construction of the appliance, taking the above-mentioned factors into consideration, is essential for optimal clinical results.
 
Article
Twists placed in an arch wire between incisor brackets are often used in an attempt to obtain root torque. This is only partially effective because of the equal and opposite reciprocals acting on the adjacent teeth. Alternatively, a V-bend in a torquing arch, inserted at only the molar and incisor brackets, may use the bending properties of the arch wire to create dissimilar moments in a two-bracket system. If the greater moment is present at the incisors, all of the incisors are rotated en masse in the same direction, with the associated equal and opposite vertical equilibrium forces directed at the incisors and molars. The lesser moment at the molar also usually has equilibrium forces that may reduce or supplement vertical forces at the molar and incisor depending on the magnitude and direction of the moment present. If the arch wire is unrestrained the resulting tooth movement shows rotation of the incisors around the CRes and movement of the CRes in the direction of the vertical equilibrium force present. The alternative use of a single force to rotate incisor crowns facially results in a reciprocal distal force at the posterior teeth and rotation of the incisors with a center of rotation apical to the CRes.
 
Article
One-couple orthodontic appliances are capable of applying well-defined forces and couples to effect controlled tooth movement during treatment. There are two sites of attachment: one in which the appliance is inserted into a bracket or tube where both a couple and force is generated, and one at which the appliance is tied as a point contact where only a force is produced. Using relatively simple designs, powerful biomechanical force systems that are easy to discern clinically can be applied to move teeth according to a prescribed plan. Several one-couple appliances are described to move individual or groups of teeth in all three dimensions. A complete biomechanical analysis of each appliance is presented and clinical reports follow each description.
 
Article
The transpalatal arch (TPA) can be activated to deliver a clinically useful array of forces and couples to move and/or rotate maxillary molars in all three planes of space. Changing the palatal arch form can produce expansion or constriction of intermolar width and activation of the inserts of the TPA will produce couples at the molar sheaths. Activations of the inserts to generate couples is possible in all three planes of space in the form of symmetrical V-bends, asymmetrical V-bends, and step bends. Although the associated equilibrium forces of a couple can be the source of clinical surprises, they can also be harnessed to produce favorable tooth movements.
 
Article
The utility arch is a two-couple intrusion arch wire used for control of anterior deep overbite. It is similar to a one-couple intrusion arch in that it is commonly made with rectangular wire, attached to the teeth only at the molars and the incisors and is activated for incisor intrusion by a molar tip back bend. It differs from a one-couple intrusion arch by the insertion of the incisor segment into the incisor brackets. This results in a fixed point of application of the intrusion force anterior to the incisors and, therefore, incisor rotation by the moment of the force. In addition, insertion of the rectangular wire into the incisor brackets usually creates a third-order couple for incisor rotation. Depending on how it is used, the moment of this couple may be activated in either direction and the resulting associated equilibrium forces will either supplement or reduce the vertical equilibrium forces created by the activation bends at the molars.
 
Article
Along with the utility arch and sectional mechanics, the quad helix appliance has become an integral part of the Bioprogressive technique. The quad helix is mostly used to unlock malocclusions and to establish normal function and arch form by expanding the dental arches. It is also a useful adjunct in the treatment of Class II malocclusions and mostly in those cases in which molar derotation is required as part of the treatment. Expansion of the alveolar ridges is only undertaken after correlating measurements taken from the study casts with those obtained from frontal cephalometric radiographs. In terms of dental arch alignment, a quad helix can achieve in 3 to 4 months what would otherwise take a great deal longer and at least a series of arch changes.
 
Article
The mechanics of V-bends in orthodontic arch wires have been described almost exclusively in terms of bending forces in two-dimensional (2-D) single plane terms. When a rectangular arch wire enters a third dimension, a more complex wire deformation pattern develops from both torsion and bending during the activation of the V-bends. The necessity for a rectangular three-dimensional (3-D) arch wire to undergo torsion during activation results in a greater resistance to deformation at those points in the wire where the torsion is greatest. This is especially apparent with 2 x 2 long span arch wires. This study used finite element analysis to model the force systems produced by activation of V-bends in 3-D arch wires. In both 2-D and 3-D data, greater moments are present as any V-bend is moved toward either adjacent bracket. In 3-D systems, however, a V-bend at the molar produces significantly less moment and associated equilibrium forces than the same V-bend located the same distance from the incisor. Moreover, the reversal of the direction of the moments at either bracket does not occur when the V-bend location is two thirds of the distance toward that tooth as reported with 2-D studies.
 
Article
All force systems applied to a tooth are composed of either single forces and/or couples. The application of a force through the center of resistance of a tooth will result in translation of the tooth. The application of a force to act at points other than through the center of resistance of a tooth will produce different tendencies for rotation. Tooth rotation resulting from the application of a force always creates a simultaneous tendency to move the center of resistance of a tooth in the direction the force is acting. In contrast, the location of a couple on a tooth is irrelevant to the resulting tooth movement. A couple can never move the center of resistance, and with a couple the center of rotation and the center of resistance will always be coincident. The equilibrium forces, associated with a moment of a couple, also are single-point forces and can produce different tooth movements depending on where they are applied. All tooth movement must be either translation and/or rotation as defined at the tooth's center of resistance.
 
Article
Changes in alignment in the untreated lower arch were studied at various developmental stages: 7 to 10 years, 10 to 12 years, 12 to 15 years, 13 to 18 years, 18 to 21 years, 21 to 28 years, and 18 to 50 years. On average, crowding decreased between 7 and 12 years and increased thereafter. The maximum increase occurred in the teenage years between 13 and 18, little or no change occurred in the third decade, and small increases occurred later in life. The possible cause of these changes is discussed in relation to the deterioration in alignment reported in orthodontically treated patients after retention.
 
Article
The historical aspects of facial esthetics and its role in orthodontic teachings and practice are traced to their origins in classical art. Related discussions include the failure of "divine proportions," the ascent of the Class II facies, and the influence of 19th century pseudoscience. Today, the treatment of facial form for a diverse society requires a tolerant sense of esthetic pluralism. Moreover, advances in neuroscience and psychology have extended understanding of the biological basis of variation in facial expression and judgment. The nature of oral esthetics was examined through quantitative studies of the smile line. Significant sexual dimorphism was found, ie, the gingival smile line (GSL) appears to be a female lineament and the low smile line seems to be a male lineament. Further results indicated that the GSL is associated with several facial characteristics, including anterior vertical maxillary excess, and the muscular capacity to raise the upper lip significantly higher than average on smiling. Other variables associated with GSL are statistically significant increases in overjet, interlabial gap at rest, and overbite. The gingival smile line is not necessarily objectionable esthetically and it will normally diminish with age. However, the treatment of choice for the GSL patient with an uncoached complaint is orthognathic surgery and orthodontics.
 
Article
Rapid advances in orthognathic surgery now allow the clinician to treat severe dentofacial deformities that were once only manageable by orthodontic camouflage. These cases were often compromised with unacceptable facial esthetics and unstable occlusal results. Over the past 25 years, there have been numerous improvements in technology and the surgical management of dentofacial deformities. These progressions now allow more predictable surgical outcomes, which ensure patient satisfaction. Not all patients are candidates for surgical treatment; therefore, patient assessment and selection remains paramount in the process of diagnosing and treatment planning for this type of irreversible treatment. The inclusion of patients in the decision-making process increases their awareness and acceptance of the final result. The past three decades indicate an increased usage of orthodontic treatment by both children and adults. Patient demographic profiles for severe occlusal and facial characteristics are presented in an effort to understand the epidemiological factors of malocclusion and predict the population's need for this service.
 
Article
One of the goals of the management of the developing occlusion and the correction of malocclusion is the establishment of symmetry within the individual arches (arch form) and the occlusal relationships between the maxillary and mandibular arches. The symmetry in arch form is related to the axial inclinations and rotations of the individual teeth. The occlusion is affected not only by the positions of the teeth, but also by the patterns of skeletal growth. Although these two components are interrelated, this discussion attempts to address them independently.
 
Article
Patients with dentoalveolar asymmetries can present some of the most biomechanically challenging situations to the orthodontist. One creative approach for managing dental asymmetries is to extract a combination of teeth that will simplify intra-arch and interarch mechanics. Often this will also reduce the dependency on patient compliance for elastic wear and may even shorten treatment time. Atypical extraction patterns can also be beneficial in the presurgical orthodontic preparation of orthognathic surgery patients. Multiple diagnostic scenarios are discussed, and various treatment plans involving asymmetric extraction patterns are reviewed.
 
Article
The orthodontic correction of dental asymmetries is often considered a difficult and challenging process, primarily because of misdiagnosis and poorly planned treatment mechanics. A careful differential diagnosis together with a thorough treatment plan can ensure successful treatment outcomes in the management of these malocclusions. In this article, key elements of differential diagnosis and treatment planning are reviewed. Different treatment strategies, including an analysis of the side effects associated with the use of these appliance systems, are described. This approach will help the clinician to best adapt treatment mechanics to a given malocclusion.
 
Article
Several aspects of the management of developmental asymmetrical facial growth are addressed. The abnormality is further defined. Methods of examination and assessment of records are discussed. A complicating factor has been the adoption of too many classification systems. With three-dimensional imaging techniques (computed tomography scan and stereophotography) great advancement has been made in efforts at describing the range of variation. Hemifacial microsomia patients are best treated in multidisciplinary centers by competent specialists with the necessary expertise and skills. The procedure followed in the craniofacial center in Rotterdam is described and discussed in relation to current treatment strategies. The success of the treatment of the asymmetrical facial growth depends on the original abnormality, on secondary abnormal development, and on orthodontic and surgical intervention. International cooperation is necessary to compile sufficient statistical data for a scientific evaluation of treatment results and to improve the effectiveness and the efficiency of treatment.
 
Article
Facial asymmetry is quite common and, when sufficiently severe, can warrant surgical orthodontic intervention. The causes of facial asymmetry are numerous and can be generally classified as congenital, developmental, or subsequent to pathology or injury. A systematic and comprehensive examination, diagnosis, and treatment plan are requirements for successful correction of facial asymmetry. Several of the more common facial asymmetries presenting for treatment to the orthodontist and surgeon are discussed in this article. Some fundamental surgical and orthodontic principles for treating these deformities are described. The purpose of this article is to provide a brief overview of a surgical and orthodontic approach to the evaluation and treatment of some of the more common facial asymmetries.
 
Article
The diagnosis, treatment planning, and design of mechanics for the asymmetric patient requires the differentiation between problems of dental and skeletal origin. Although much information can be gleaned from a cephalometric analysis, the clinical examination and study models offer important clues in establishing the diagnosis of skeletal discrepancy. Abnormal and asymmetric axial inclinations can either produce a dental asymmetry or, if compensatory in nature, may mask an underlying skeletal problem. The role of axial inclination in diagnosis is applied to the following situations: subdivision cases, unilateral crossbites, midline discrepancies, arch form deviations, and frontal cants to the occlusal plane. The management of axial inclination asymmetries depends on the treatment plan. Nonextraction patients may require maintenance of asymmetric compensatory axial inclinations. Surgical and extraction patients can be treated to a more ideal symmetry.
 
Article
Epidemiological studies of the occlusal status of the US population do not include the prevalence of orthodontic asymmetries. To estimate the magnitude of dental and facial asymmetries in adolescents with no history of orthodontic treatment, data were analyzed from two mass orthodontic screenings that had been conducted on public schoolchildren in Florida. An analysis of orthodontic records of patients in treatment at the Virginia Commonwealth University graduate orthodontic clinic provided prevalence data on dental and facial asymmetries in a population of orthodontic patients. In the Florida studies, the two screenings yielded 5,817 untreated children (mean age, 9.3 +/- 0.8 years) and 861 untreated children (mean age, 14.4 +/- 0.5 years). Sagittal molar asymmetry was found in 30% of the children in the first screening and in 23% in the second screening. Additional asymmetry assessments in the second screening showed 12% facial asymmetry and 21% noncoincidence of dental midlines. Among orthodontic patients, the most common asymmetry trait was mandibular midline deviation from the facial midline. This occurred in 62% of patients, followed, in descending order of frequency, by lack of dental midline coincidence (46%), maxillary midline deviation from the facial midline (39%), molar classification asymmetry (22%), maxillary occlusal asymmetry (20%), mandibular occlusal asymmetry (18%), facial asymmetry (6%), chin deviation (4%), and nose deviation (3%).
 
Article
Problems and failures in orthodontic-orthognathic surgical treatment are frequently discussed among colleagues, but not often written about. This lack of documentation may be attributed to a natural inclination for us to report our successes and hide our failures. More positively, we believe the lack of written material on complications probably relates more to the overwhelming success rate in these procedures than to an inclination to hide failures. In addition, some complications are clearly a result of the orthodontic care before and/or after the surgical procedure. This article concentrates on exploring the many complications in orthognathic surgery that are more a result of the orthodontic phase of care, and how the orthodontist can react to and manage surgical complications to achieve a successful result. The more the orthodontist understands the nature of surgical problems, the more able he/she is to manage them.
 
Article
As the orthodontic profession prepares to enter the next millennium, clinicians around the world seek new diagnostic tools that will enable them to enhance their treatment results. They seek improved treatment efficiency that will allow them to treat more patients with less chairside time, with less relapse, and with greater profitability. They seek logic and order in their patient care decisions, and a biologically sound methodology for treatment. Those who strive for excellence in orthodontics will seek the benefits of new technology in diagnosis and treatment. They will embrace computers to help organize their thoughts and discipline their treatment as well as relentlessly seek new methods to grow professionally. This article discusses the marriage of the Bioprogressive philosophy with the Zero Base logic system as the sensible approach to achieving the above-mentioned objectives.
 
Article
Dentists cannot afford to be ignorant about insurance. Insurance is an important risk-management tool, minimizing the exposure for catastrophic claims and losses. Patient insurance is also a major source of revenue for most dental practices.
 
Article
This study used a preexisting database to test in hypothesis from the appropriateness of some common orthodontic beliefs concerning upper first molar displacement and changes in facial morphology associated with conventional full bonded/banded treatment in growing subjects. In an initial pass, the author used data from a stratified random sample of 48 subjects drawn retrospectively from the practice of a single, experienced orthodontist. This sample consisted of 4 subgroups of 12 subjects each: Class I nonextraction, Class I extraction, Class II nonextraction, and Class II extraction. The findings indicate that, relative to the facial profile, chin point did not, on average, displace anteriorly during treatment, either overall or in any subgroup. Relative to the facial profile, Point A became significantly less prominent during treatment, both overall and in each subgroup. The best estimate of the mean displacement of the upper molar cusp relative to superimposition on Anterior Cranial Base was in the mesial direction in each of the four subgroups. In only one extraction subject out of 24 did the cusp appear to be displaced distally. Mesial molar cusp displacement was significantly greater in the Class II extraction subgroup than in the Class II nonextraction subgroup. Relative to superimposition on anatomical "best fit" of maxillary structures, the findings for molar cusp displacement were similar, but even more dramatic. Mean mesial migration was highly significant in both the Class II nonextraction and Class II extraction subgroups. In no subject in the entire sample was distal displacement noted relative to this superimposition. Mean increase in anterior Total Face Height was significantly greater in the Class II extraction subgroup than in the Class II nonextraction subgroup. (This finding was contrary to the author's original expectation.) The generalizability of the findings from the initial pass to other treated growing subjects was then assessed by retesting modified hypotheses against a second database stored sample that earlier had been drawn randomly from two other orthodontic practices. The implications of the author's study strategy to the design of future shared digital databases is discussed briefly.
 
Article
Conservative non-presurgical orthopedic treatment in complete bilateral cleft lip and palate (CBCLP) cases were compared with those treated will the Millard-Latham (M-L) method, which involves the presurgical mechanical retraction of the protruding premaxilla using pinned palatal appliances. In conservatively treated cases, a head bonnet with an external elastic is sometimes used before surgical lip closure to ventroflex the premaxilla thereby reducing tension at the surgical sites. The M-L method involves premaxillary bodily retraction followed by a gingivo-periosteoplasty. In both series of cases the palatal cleft (hard and soft) is closed for patients aged 18 to 30 months using a modified von Langenbeck procedure. A secondary alveolar bone graft is only performed in the conservatively treated series for patients aged 7 to 9 years. Although the premaxilla in 2 of 29 conservatively treated cases were retruded and in anterior crossbite by 10 to 12 years of age, all M-L cases were retruded by 9 years of age requiring maxillary protraction. In the M-L cases 90% showed bony bridging of the alveolar cleft with frequent loss of the lateral incisor space; surgical closure of the nasal floor is facilitated, and early aesthetic improvement is followed by midfacial retrusion.
 
Article
Symptoms and signs of temporomandibular disorders were assessed in children enrolled in a randomized controlled trial of early treatment for Class II malocclusion. Children (mean age of 9.8 years) were assigned to a treatment protocol (bionator, n = 60; observation, n = 60; headgear/bite plane, n = 71) using randomized block stratification. Temporomandibular joint (TMJ) sounds, joint capsule pain to palpation, and muscle pain to palpation were scored as binary responses (present/absent in a subject). Determinations were made by blinded, calibrated examiners initially (DC1) and after a Class I molar correction was achieved or 2 years had elapsed (DC3). Univariate relationships among explanatory factors (group assignment, gender, age, time interval between DC1 and DC3, Class II severity, mandibular plane angle, preparatory treatment, whether Class I molar relation was achieved) and binary responses were explored using Chi square tables and ANOVA methods. Logistic regression modeled the relationship between binary responses and the explanatory variables. At DC1, the 3 groups were equivalent in the explanatory variables (P > .05). Subjects with a TMJ sound, joint pain, and/or muscle pain at follow-up were more likely those who had the sign at baseline (P < .01). Early treatment with bionators and headgear/bite planes did not place healthy children without these signs at risk for developing these signs. Only increasing age (for the development of sounds, P < .04) and failure to achieve a Class I molar relation (for development of muscle pain, P < .04) placed sign-free children at greater risk. Subjects with TMJ pain at baseline were 7 times more likely to have pain at follow-up if they had been treated with a headgear/bite plane or observed than if they had been treated with a bionator (P = .007). We conclude that an immediate benefit or risk for children receiving early Class II treatment with bionators and headgear/bite planes with respect to temporomandibular joint function does not exist with the prospect that Class II children with TMJ capsule pain may benefit from bionator therapy.
 
Article
This article provides a brief overview of the history of orthodontic practice and comments on the "era of limitations" that exemplified orthodontic thinking in the 1930s. In contrast, the Bioprogressive philosophy of orthodontic treatment which developed 2 decades later resulted from an attitude of academic and clinical freedom. The Bioprogressive philosophy brought many aspects of biology and function into the arena of orthodontic therapy. This technique does not follow a series of rigidly fixed treatment steps, but rather stresses a number of orthodontic principles that have stood the test of time. This article revisits and updates the Bioprogressive principles in line with the latest developments in biology and orthodontic materials.
 
Top-cited authors
James A McNamara
  • University of Michigan
Wilbur Eugene Roberts
  • Indiana University-Purdue University Indianapolis
Adrian Becker
  • Hebrew University of Jerusalem
Nabil F Bissada
  • Case Western Reserve University
Steven Lindauer
  • Virginia Commonwealth University