Patrick K. Turley

Cephalometric effects of face mask/expansion therapy in Class III children: a comparison of three age groups.

The purpose of this investigation was to determine the skeletal, dental, and soft tissue effects of face mask/expansion therapy and to examine the effect of age on treatment response. Pretreatment and posttreatment cephalometric radiographs from 63 subjects (4 to 13 years) who had a Class III malocclusion were analyzed. Serial cephalometric tracings of 32 subjects with Class I occlusion made at 4, 6, 8, 10, 12, and 14 years were used as controls. Landmarks were digitized on each tracing and treatment effects were measured by using cranial base and maxillary superimposition techniques. Annual rate differences were compared with t tests for the combined treated group (N = 63) and between stratified treated groups (4 to 7 years N = 15, 7 to 10 years N = 32, 10 to 14 years N = 16). The treated group (N = 63) demonstrated significant (p < 0.001) hard and soft tissue changes that resulted from treatment. Skeletal change was primarily a result of anterior and vertical movement of the maxillae. Mandibular position was directed in a downward and backward vector. Orthodontic changes contributed to the correction, and soft tissue effects resulted in a more convex profile. Minimal significant differences were observed between age groups when comparing angular and linear measurements alone. However, when analyzing the algebraic sum of treatment effects (Johnston analysis), significantly (p < 0.01) greater differences were observed in apical base change (ABCH) and total molar correction (6/6) in the younger age groups. This study demonstrates that face mask/expansion therapy produces dentofacial changes that combine to improve the Class III malocclusion. Although early treatment may be most effective, face mask therapy can provide a viable option for older children as well.

Cephalometric changes after the correction of Class III malocclusion with maxillary expansion/facemask therapy☆☆☆★

The purpose of this study was to analyze the cephalometric changes that occurred during and after the correction of Class III malocclusion. The records of 24 Class III patients treated with a banded expansion appliance and custom facemask were compared with 24 Class I and 27 Class III untreated controls. Cephalometric means were calculated for the annualized data and compared univariately with unpaired t tests to determine significant differences. Treatment results showed more convexity of the facial profile from anterior displacement and downward and backward rotation of the maxilla and clockwise rotation of the mandible. The maxillary teeth moved forward while the lower incisors retruded. Postprotraction results showed the maxilla did not relapse after treatment but grew anteriorly similar to the Class III controls but less than the Class I controls. Mandibular growth was similar for the treatment and control groups. Dental changes compensated for decreasing overjet whereas the soft tissue profile showed no significant posttreatment changes. Results in the intercontrol comparison showed the Class III controls had significantly less forward movement of A-point and greater forward movement of the mandible than Class I controls. Because of these differences using a Class I control group to compare to a Class III treatment group will tend to underestimate the treatment effects and overestimate posttreatment changes. Overcorrection of the Class III malocclusion is recommended to compensate for postprotraction growth deficiency of the maxilla.

Analysis of stress in the periodontium of the maxillary first molar with a three-dimensional finite element model

The aim of this study was to simulate the stress response in the periodontium of the maxillary first molar to different moment to force ratios, and to determine the moment to force ratio for translational movement of the tooth by means of the finite element method. The three-dimensional finite element model of the maxillary first molar consisted of 3097 nodes and 2521 isoparametric eight-node solid elements. The model was designed to dissect the periodontal ligament, root, and alveolar bone separately. The results demonstrate the sensitivity of the periodontium to load changes. The stress pattern in the periodontal ligament for a distalizing force without counterbalancing moments showed high concentration at the cervical level of the distobuccal root due to tipping and rotation of the tooth. After various counterrotation as well as countertipping moments were applied, an even distribution of low compression on the distal side of the periodontal ligament was obtained at a countertipping moment to force ratio of 9:1 and a counterrotation moment to force ratio of 5:1. This lower and uniform stress in the periodontal ligament implies that a translational tooth movement may be achieved. Furthermore, high stress concentration was observed on the root surface at the furcation level in contrast with anterior teeth reported to display high concentration at the apex. This result may suggest that the root morphology of the maxillary first molar makes it less susceptible to apical root resorption relative to anterior teeth during tooth movement. The stress patterns in the periodontal ligament corresponded with the load types; those on the root appeared to be highly affected by bending and the high stiffness of the root.

The effects of space closure of the mandibular first molar area in adults

There is little information regarding the orthodontic closure of remodeled, edentulous spaces in the posterior area of the mandible. The present study was undertaken to determine the dental and periodontal changes that occur when mandibular first molar areas are closed in adults. Fourteen adult patients were selected from private orthodontic practices. Pre- and posttreatment study models were used to measure the mesiodistal length of the edentulous space and the buccolingual width of the alveolar ridge. The amount of crown and root movement of the second molar and premolar was measured from lateral cephalometric radiographs. From pre- and posttreatment panoramic or periapical radiographs, the anatomic changes of the second molar and adjacent periodontium were also measured. Every case showed significant space closure (x = 6.2 mm) ranging from 2.7 to 11.5 mm. There was crestal bone loss (x = 1.3 mm) mesial to the second molar in all but five cases. These latter cases showed bone addition. As the molar moved mesially , the alveolar ridge increased in width an average of 1.2 mm. The adult patient who showed the greatest amount of space closure and the least amount of molar bone loss had (1) mesiodistal space of 6.0 mm, (2) buccolingual ridge width of 7.0 mm, and (3) mesial molar bone level 1.0 mm apical to the cementoenamel junction. The results of this study indicate that space closure is not only possible but may aid the treatment of certain cases. Space closure should be considered as a potential solution to the absence of mandibular first permanent molars.

The effect of orthodontic extrusion on traumatically intruded teeth

The management of traumatically intruded permanent incisors is controversial. Some authors suggest a decreased incidence of ankylosis in cases treated with orthodontic extrusion. The purpose of this study was to examine two common management techniques for traumatic intrusion, orthodontic extrusion, and observation for re-eruption. The four first premolars of three shepherd dogs were traumatically intruded with a mallet while a holding device was used to prevent tooth fracture. Five to 7 days following the injury, orthodontic force was applied unilaterally while the contralateral tooth served as the untreated control. To facilitate serial periapical radiography, x-ray jigs were fabricated for each animal and tantalum implants were placed in the bone distal to the permanent canine and first and second premolars. Observations included radiographic measurement of tooth movement, clinical estimates of tooth mobility, and radiographic and histologic assessment of root resorption, ankylosis, and periapical pathosis. The amount of traumatic intrusion varied from less than 0.5 to 4.1 mm. Following 11 to 13 weeks of force activation, 10 of 12 traumatized teeth showed clinical, radiographic, and histologic evidence of ankylosis irrespective of orthodontic treatment. Whereas the ankylosed teeth did not move with orthodontic forces, the teeth used for force application were orthodontically intruded 1.7 to 6.5 mm. When the injury to the tooth was severe, orthodontic extrusion had little effect on repositioning of the injured tooth but resulted in undesirable movement of the anchorage teeth. When the injury was less severe, orthodontic forces facilitated repositioning of the affected tooth.

The clinical management of ectopically erupting first permanent molars

The literature on ectopically erupting first permanent molars is reviewed. The progression of the ectopic condition is discussed along with factors that will affect the practitioners decision on a mode of treatment. The optimal treatment approach depends on the clinical eruption status of /6/, the change in position of /6/, the amount of enamel ledge of /E/ entrapping /6/, the mobility of /E/, and the presence of pain or infection. A variety of treatment approaches together with diagnostic rationale and clinical guidelines are presented. Overall aspects of the malocclusion must be considered when planning the management of ectopically erupting first permanent molars.

Orthodontic management of theshort face patient

A short lower face may accompany various types of malocclusions dependingon the structural etiology. Because most cephalometric analyses focus on the anteroposterior plane of space, they are often insufficient in diagnosing a significant vertical dysplasia. This article describes a cephalometric analysis that examines not only the vertical proportions of the face, but the various anatomical features that contribute to the dysplasia. Diagnosis is further enhanced by evaluating the facial profile with the mandible postured at various amounts of opening, suggesting the degree of vertical discrepancy. Traditional orthodontic therapy corrects the associated malocclusion but is usually ineffective in changing inherent facial proportions. However, several orthopedic methods have shown the ability to increase lower facial height when used in combination with nonextraction orthodontic mechanotherapy. Adults with short faces require a combination of orthodontics and orthognathic surgery. The Class II malocclusion can usually be managed by surgically advancing the mandible with the curve of Spee maintained. In cases of vertical maxillary deficiency, the LeFort I osteotomy with inferior repositioning provides the spatial correction that is needed. Two cases are presented to illustrate the cephalometric and facial analyses used in diagnosis, as well as the common surgical procedures to manage the short face patient.

An American Board of Orthodontics case report: The surgical-orthodontic management of a Class I malocclusion with excessive overbite and periodontal bone loss

[This case report is presented in partial fulfillment of the requirements for the certification process conducted by the Board.]

Child abuse prevention month

April is National Child Abuse Prevention Month (sponsored by the US Department of Health and Human Services). Child abuse is well known to most of us because of its attention in medicine, government social service agencies, and especially the media. It is not usually a topic of discussion in orthodontic circles. It is, however, a subject that all of us who interact with children on a regular basis should be aware of. Other than the teacher, the orthodontist may see the child more often than any other professional. My oldest brother taught primary school in Southern California for over 30 years. Before retiring, he received this letter from a former student who had been a victim of child abuse. She wrote the following.