David B. Kennedy

Uncovering labially impacted teeth: apically positioned flap and closed-eruption techniques

The purpose of this study was to examine the esthetic and periodontal differences between two methods of uncovering labially impacted maxillary anterior teeth: the apically positioned flap and closed-eruption techniques. The sample consisted of 30 patients who were recalled a minimum of three months after orthodontic treatment of a unilateral labially impacted maxillary anterior tooth. Eighteen of the patients had undergone an apically positioned flap (APF) procedure, and the remaining twelve had undergone the closed-eruption (CE) technique. In the CE group, clinical examination showed less width of attached gingiva on the distal surface and increased probing bone level on the facial surface of the uncovered teeth relative to their contralateral controls. Uncovered teeth in the APF group showed more apical gingival margins on the mesial and facial surfaces; greater crown length on the midfacial surface; increased probing attachment level on the facial surface; increased width of attached gingiva on the facial surface; increased probing bone level on mesial, facial, and distal surfaces; and gingival scarring. Radiographic examination showed shorter roots on the uncovered teeth in both groups. Photographic examination revealed vertical relapse of the uncovered teeth in the APF group. We conclude that labially impacted maxillary anterior teeth uncovered with an apically positioned flap technique have more unesthetic sequalae than those uncovered with a closed-eruption technique.

Changes in condylar position and occlusion associated with maxillary expansion for correction of functional unilateral posterior crossbite

The purpose of this study was to confirm that correction of functional posterior crossbite through maxillary expansion is associated with a change in condylar position and occlusal relationships, and to determine whether maxillary expansion is associated with autonomous increase in mandibular arch width. Pretreatment and posttreatment study models of 61 patients ages 4.1 to 12.0 years (mean 8.5 years, SD 1.5) were available after maxillary expansion with a Quad Helix or a Haas expander for correction of a functional posterior crossbite. Pretreatment and posttreatment tomograms were available for 22 of the patients. Tomographic evaluation revealed that the condyles moved posteriorly and superiorly on the noncrossbite side from before to after treatment (p < 0.05). No differences were observed on the crossbite side. Superior joint space was greatest on the noncrossbite side before treatment, whereas, conversely, it was greatest on the crossbite side after treatment (p < 0.05). Relative condylar position was more anterior on the noncrossbite side before treatment (p < 0.05), but similar on both sides after treatment. Molar and canine relationships were more Class II on the crossbite side before treatment (p < 0.01 and < 0.05, respectively) and similar on both sides after treatment. A significant reduction in midline deviation was seen from before to after treatment (p < 0.001). A small, but significant autonomous increase in mandibular intermolar width (p < 0.001) occurred concomitant with the maxillary expansion.

Pulpal and periodontal reactions to orthodontic alignment of palatally impacted canines

The purpose of this study was to evaluate differences in periodontal and pulpal status, root length, and tooth alignment between contralateral maxillary lateral incisors, canines, and premolars in patients treated for unilateral impaction of maxillary canines. Clinical examinations were performed on 32 patients, average age 22 years 11 months and average posttreatment observation period 3 years 7 months. Probing attachment level was lower at the mesial and distal aspect of the previously impacted canine and at the distal aspect of the adjacent lateral incisor. Crestal bone height was lower at the mesial aspect of the previously impacted canine and at the distal aspect of the adjacent lateral incisor. The roots of the lateral incisors and premolars adjacent to the previously impacted canines were shorter. Pulpal obliteration was observed in six previously impacted canines (21%), and pulp necrosis in one previously impacted canine. The pulps of the remaining teeth appeared normal radiographically. A negative response to electric pulp testing was observed in eight previously impacted canines. Approximately 40% of the previously impacted canines exhibited noticeable relapse and were judged to be intruded, lingually displaced, mesially rotated, as well as discolored. Of the contralateral canines, 91% were normal in appearance. The previously impacted canine could be identified on posttreatment color slides in approximately 75% of the cases.

The effect of extraction and orthodontic treatment on dentoalveolar support

Full-mouth radiographs of ninety-six patients treated by extraction of four first premolars were taken at least 10 years postextraction. Three groups were established: one with extensive crowding in the full permanent dentition treated by extraction and fixed appliance therapy; one treated by serial extraction and fixed appliance therapy; and one treated by serial extraction only. Measurements of tooth length and alveolar bone height were made from the projected radiographs, and buccolingual socket areas were measured from direct tracings of the radiographs. Comparison between groups revealed reduced mean radiographic tooth lengths for incisors and mandibular molars in the orthodontically treated groups. The incidence of root resorption was similar for both treated groups. Reduced alveolar bone heights were noted in the extraction sites of the two orthodontically treated groups but not in the group treated by serial extraction only. Most reduction in long-term dentoalveolar support occurred as a result of root resorption except in the extraction sites, where it occurred largely as a result of bone loss. Root parallelism did not appear to influence proximal bone heights at the extraction site. In malocclusions involving arch length deficiency, maximally displaced canines had reduced long-term proximal bone compared to nondisplaced canines, supporting the concept of encouraging autonomous distal eruption through serial extraction.

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.

Arch dimension changes from successful slow maxillary expansion of unilateral posterior crossbite

OBJECTIVE To evaluate the long-term effects of successful slow maxillary expansion without fixed appliances or retainers in the mixed dentition on patients with unilateral crossbites, using Haas-type, hyrax, or quad helix appliances. MATERIALS AND METHODS Serial dental casts of 110 patients were evaluated at three time points: preexpansion (T1) (mean age 7 years/7 months), postexpansion (T2) (mean age 8 years/8 months), and approximately 4 years later in the permanent dentition (T3) (mean age 12 years/9 months). Maxillary and mandibular intercanine and intermolar widths, arch length, and perimeter and molar angulation were measured at all three time intervals with the Michigan published growth norms serving as a control. RESULTS Successful treatment by slow maxillary expansion (SME) produced similarly favorable expansion by all three expanders in all measurements for both arches. Maxillary arch widths were narrower than controls pretreatment (T1) and wider than controls immediately post treatment (T2). Long-term (T3) maxillary intermolar width was the same as controls, with intercanine width significantly wider than controls. Maxillary intercanine and intermolar width increased from T1 to T3, by 4.5 mm and 3.5 mm, respectively, with 98% of intercanine and 80% of intermolar expansion remaining at T3. Maxillary arch circumference increased by 1 mm from T1 to T3. Mandibular width did not change significantly. CONCLUSION Maxillary arch dimensions in early mixed dentition in patients with unilateral posterior crossbite showed good stability 4 years post treatment in the permanent dentition.

Management of a Class I malocclusion with traumatically avulsed maxillary central and lateral incisors

This case report describes orthodontic space closure for managing an avulsed maxillary central incisor and a lateral incisor in a growing girl with a Class I deep bite malocclusion with moderate lower and mild upper crowding. The treatment approach moved a central incisor across the midline and substituted a lateral incisor for a central incisor, in combination with canine substitution. Veneers on all maxillary anterior teeth attained acceptable esthetics. The right central incisor was moved to serve as the avulsed left central incisor. The right lateral incisor was moved to the position of the right central incisor and restored. The canines on both sides were substituted as lateral incisors; the posterior occlusion was left in Class II. Mesialization of central and lateral incisors with prosthetic rehabilitation is an acceptable treatment option.

Dimensional changes in the palate associated with slow maxillary expansion for early treatment of posterior crossbite

OBJECTIVES To compare palatal symmetry, dimensions, and molar angulations following early mixed-dentition slow maxillary expansion with parameters in normal controls. MATERIALS AND METHODS A total of 30 patients treated with a Haas-type expander for unilateral posterior crossbite with functional shift were compared with 30 controls matched for dental age, gender, and molar relationship. Records were taken before (T1) and after expansion (T2). Palatal width, surface area, volume, and molar angulations were measured on digitized models. Surface area and volume were split in half then divided into anterior, middle, and posterior segments to measure symmetry. Students t-test was used to assess group differences. RESULTS Mean intercanine width increased 4.65 mm, and intermolar width increased 4.76 mm. The treated mean surface area increased 127.05 mm2 compared with 10.35 mm2 in controls. The treated palatal volume increased 927.55 mm3 compared with 159.89 mm3 for controls. At T1, the controls showed significant differences in surface area and volume between the anterior palatal segments. At T2, this difference occurred in surface area of middle palatal segments of the treated sample. First permanent molars showed an increased buccal and distal inclination after treatment, opposite to controls. The increase in buccal inclination was greater on the crossbite side. CONCLUSIONS The Haas-type expander results in similar expansion across the canines and first molars. A palate that is symmetrical before expansion may become asymmetric after expansion but only in the middle segment. Changes in individual molar angulation following palatal expansion can be measured without radiation imaging.