Treatment of a patient with multiple impacted teeth.

An impacted or missing permanent tooth can add significant complications to an otherwise straightforward case. When multiple impacted teeth are present, the case complexity increases further. Developing a treatment sequence, determining appropriate anchorage, and planning and executing sound biomechanics can be a challenge.

Correction of severe obstructive sleep apnea with bimaxillary transverse distraction osteogenesis and maxillomandibular advancement.

Obstructive sleep apnea (OSA) can be a debilitating, even life-threatening, condition. The most favorable treatment for patients with OSA is multidisciplinary care by a team that represents various dental and medical disciplines. Prescribed therapies might include weight loss, behavior modification, oral appliances, soft tissue surgery, skeletal surgery, or some combination of approaches.

Mandibular symphyseal distraction osteogenesis: diagnosis and treatment planning considerations.

Treatment planning decisions in the transverse dimension have historically been based on the presenting mandibular arch width and form. Distraction osteogenesis (DO), originally developed by Russian orthopedic surgeon Ilizarov, has produced significant results in limb lengthening. Mandibular symphyseal DO was introduced by Guerrero, providing a new paradigm for patients whose treatment alternatives and results were previously limited.

Correction of severe vertical maxillary excess with anterior open bite and transverse maxillary deficiency.

Patients requiring correction of large anterior open bites have historically been among the most challenging treatments for orthodontists. Adding to that fundamental challenge for the adult patient in this case was vertical maxillary excess, a severe transverse maxillary deficiency as well as an arch length inadequacy, even though the patient had prior orthodontic treatment. The prior orthodontist had included arch expansion and extracted four first bicuspids, which limited current treatment options.

Condylar displacement related to mandibular symphyseal distraction.

This study was undertaken to determine the true nature of condylar displacements associated with mandibular symphyseal distraction osteogenesis. Earlier investigators have assumed that each mandibular half rotated about a point near the center of each condyle as viewed on a submental radiograph. In a 12-patient sample, 10 with tooth-borne symphyseal distraction and 2 with bone-borne symphyseal distraction, it was found that each condyle was laterally displaced in direct relationship to the amount of symphyseal distraction.

Taking the guesswork out of mandibular symphyseal distraction osteogenesis.

Mandibular symphyseal distraction osteogenesis has recently been introduced as a means of resolving arch length deficiencies in the anterior segment and as a method of reducing large vestibular spaces related to a narrow mandible. Accurately relating the required distraction for a given anterior tooth mass and desired future anteroposterior location of the central incisors has not been possible until recently. The relationship between these 3 controlling factors has been mathematically described by the hyperbolic cosine function and a computer program designed for easy use by the clinician.

The relationship of the glenoid fossa to the functional occlusal plane.

The geometric relationship of the functional occlusal plane to the center of the glenoid fossa, as seen in the sagittal view, is described for males and females from age 7 through 25 years. This relationship is fully described by the distance from the geometric center of the glenoid fossa perpendicular to the functional occlusal plane (L, in millimeters) and its angulation (theta, in degrees) relative to a constructed Frankfort horizontal (SN-7 degrees ). Regression formulas with 95% confidence levels are described for L and theta for both genders combined.

The biomechanics of rapid maxillary sutural expansion.

Micro-displacements (fringe patterns) in the bones of the craniofacial complex as seen through laser holography during midpalatal sutural expansion with the Hyrax appliance are used to define the centers of rotation of the maxillary halves in both the frontal and occlusal views. Biomechanical analyses of the maxillary expansion force system are concomitant with the holographic findings and strongly suggest that the stainless steel wires joining the teeth to any expansion device be of the largest diameter possible. In addition, in the case of the Hyrax expansion device, it is recommended that the manufacturer increase the diameter of the activating screw as well as those of the 2 adjacent wire guides.

The relationship of arch length to alterations in dental arch width.

An accurate method is presented for forecasting alterations in arch length related to various width increases in each dental arch. It is based on combined beta and hyperbolic cosine functions which express the expanded dental arches with correlation coefficients of r = 0.98, between measured data and representations of the dental arch.

An evaluation of the shape of some popular nickel titanium alloy preformed arch wires.

The mathematical Beta function is shown to be an accurate planar representation of the natural human arch form defined by the spatial coordinates of the labial and buccal dental/bracket interfacing surfaces in the maxillary and mandibular arches. Graphic planar representations of the corresponding bracket base spatial coordinates of 33 popular preformed nickel titanium arch wires and bracket assemblies were superimposed on each of the relevant maxillary and mandibular natural forms. The arch forms of the preformed nickel titanium arch wires and bracket assemblies did not emulate the natural human arch form.

Assessment, documentation, and treatment of a developing facial asymmetry following early childhood injury.

Prepubertal trauma is often implicated as the cause of asymmetric growth of the mandible. A series of photographs taken before and after early childhood injury to the orofacial complex illustrates the development of a three-dimensional dentofacial deformity in a patient. The diagnosis and combined surgical orthodontic treatment plan to correct the facial asymmetry and malocclusion are discussed.

A reexamination of various extraoral appliances in light of recent research findings.

The location of the center of resistance of the dentomaxillary complex has recently been identified more accurately than before. Based on this new finding, various modifications of the common facebow are presented for use in protraction therapy. Clinical applications for specific treatment objectives are also reviewed.

Surgical correction of patients with asymmetries.

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.

The form of the human dental arch.

The human dental arch form is shown to be accurately represented mathematically by the beta function. The average correlation coefficient between measured arch-shape data and the mathematical arch shape, expressed by the beta function, is 0.98 with a standard deviation of 0.

On the management of extraction sites.

Extraction sites may be needed to achieve specific orthodontic goals of positioning the dentition within the craniofacial complex. The fundamental reality that determines the final position of the dentition, however, is the control exercised by the clinician in closure of the extraction sites. A specific treatment objective may require the posterior teeth to remain in a constant position anteroposteriorly as well as vertically, while the anterior teeth occupy the entire extraction site.

Changes in occlusion related to the cant of the occlusal plane.

It is known that dental occlusion is influenced by changes in the cant of the occlusal plane. This study has defined the geometric and mathematical relationships between dental occlusion and rotations of the occlusal plane in the sagittal view. As a general clinical guide, each degree of rotation of the occlusal plane will result in a half millimeter change in the dental occlusal relationship.

Variable modulus orthodontics advanced through an auxiliary archwire attachment.

Reducing the load deflection rates of orthodontic springs is important, for it provides relative constancy of the moment-to-force ratio applied to the teeth with concomitant, forecastable dental movement. Increasing patient comfort and reducing the number of office visits while lowering potential tissue damage are additional features of lower load deflection rate springs. A simple auxiliary attachment, which can be crimped into position on an archwire or onto segments of an archwire, is described.

A cancellous marrow bone-cartilage composite autograft for maxillofacial reconstructive surgery. A case report.

Numerous experimental and clinical investigations have contributed to current protocol for the reconstruction of hard tissue defects of the face and jaws. Free transplantation of tissues from the same host is a viable option for these defects. This article includes a review of the literature for autogenous grafting and presents an example of this treatment with a 19-month follow-up.

Masseter muscle adaptation following surgical correction of vertical maxillary excess.

This study was designed to examine the adaptive response of the human masseter muscle following surgical correction of abnormal facial form. Biopsies of the deep surface of the anterior superficial masseter muscle were obtained from five patients demonstrating vertical maxillary excess (VME), one at the time of corrective surgery, and a second at a long-term postoperative time interval (mean, 8 months). Control biopsies were also obtained from five individuals (three cadavers and two patients) with normal dentofacial morphology.

Treatment of Class II deep bite by orthodontic and surgical means.

Conventional orthodontic correction of the Class II deep-bite deformity with a decreased lower anterior facial height tendency can be mechanically difficult, inefficient and, in many instances, impossible. Orthodontic treatment alone of either adults or adolescents with such deformities frequently can neither increase lower anterior facial height sufficiently to achieve ideal facial proportions nor achieve long-term occlusal stability. Despite the need for surgical intervention to achieve satisfactory occlusal and esthetic results, many patients with such deformities are still being treated in clinical practice by traditional orthodontic procedures, with less than ideal esthetic and/or occlusal results.

An evaluation of soft-tissue changes resulting from Le Fort I maxillary surgery.

The soft-tissue profile response to maxillary surgery (impaction and advancement) at the Le Fort I level was evaluated. Data were derived from quality-controlled preoperative and postoperative cephalograms of nongrowing patients with their lips in repose. A standardized tracing technique was used, and this was followed by landmark identification and digitization.