Long-term profile changes associated with successfully treated extraction and nonextraction Class II Division 1 malocclusions.

This study was undertaken to compare the post-treatment and long-term soft tissue profiles of successfully managed and stable Class II, division 1 malocclusions treated with either 4 first premolar extractions or nonextraction therapy. It was hypothesized that, if sound extraction decisions were made according to accepted treatment objectives and successful treatment outcomes were achieved, there should be no differences between groups in soft tissue profiles post-treatment and long-term post-retention. The sample consisted of 63 Caucasian adolescents (23 extraction, 40 nonextraction). Correction of the malocclusion was achieved using a combination of cervical headgear concurrent with mandibular growth and maxillary incisor retraction. Pretreatment, post-treatment, and long-term post-retention lateral cephalometric radiographs were evaluated. The soft tissue facial profiles of the extraction and nonextraction samples were the same following active treatment and long-term post-retention. Progressive flattening of the facial profile was observed in both samples. This flattening was attributed to the maturational changes associated with continued mandibular growth and nasal development and was not influenced by whether or not teeth were removed. Long-term lip positions were more retrusive than the ideals suggested by Ricketts and Steiner, but close to the values reported for normal, untreated adults of similar ages. The pretreatment position and thickness of the lower lip as well as the initial maxillomandibular skeletal relationship may be predictors of post-treatment or long-term lower lip position.

Long-term stability of mandibular orthopedic repositioning.

Mandibular anterior repositioning appliances attempt to diminish temporomandibular joint pain, soft tissue noise, and myofascial discomfort by altering condyle-disc relationships. Secondary stabilization of the occlusion to this arbitrary anterior position through orthodontic tooth movement may significantly alter functional and muscular relationships. A case report is illustrated to show that as the functional environment attempted to reestablish equilibrium through adaptation, relapse occurred as the condyles "seated" posteriorly and superiorly toward their original relationship within the fossa. For all practical purposes, complete relapse of the orthodontic treatment result took place over time.

Comparison of soft tissue profile changes in serial extraction and late premolar extraction.

To assess soft tissue profile changes through time, a comparison was made of patients treated by serial extraction without subsequent orthodontic treatment (n=28), patients treated with serial extraction and orthodontic treatment (n=30), and patients treated orthodontically with late extraction (n=30). Cephalometric radiographs were traced and digitized; linear and angular measurements were made with a custom computer program that allowed digitization of specific soft tissue points. Maxillary, mandibular, and overall cephalometric superimpositions and linear measurements of change from the superimpositions were done by hand. Statistical analyses were made to determine if significant differences existed within each group at each time period and between groups at each time period, as well as between males and females at each time period. Data were also analyzed to determine if significant correlations existed between any hard tissue variable and any soft tissue variable, or between any soft tissue variable and any other soft tissue variable. It was found that in those patients treated with late premolar extraction, the most labial point of the mandibular incisor was more posterior from pretreatment to posttreatment than in the serial extraction group. While a great number of associations existed between variables, no significant differences were found between the soft tissue profiles of these three groups of patients. The gender differences that were found to exist were most likely due to normal maturational changes, not the treatment itself.

Changes in condylar postition 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.

Long-term stability of Angle Class II, division 1 malocclusions with successful occlusal results at end of active treatment.

The purpose of this study was to examine long-term stability of Angle Class II, Division 1 malocclusions with successful occlusal results at the end of active appliance therapy, search for predictors of relapse, and look for characteristics associated with successful treatment. Records taken before and after treatment and a mean of 14.0 years postretention of adolescent patients treated for a significant Angle Class II, Division 1 malocclusion both with and without tooth extraction were evaluated. The sample was limited to successfully treated cases as judged by subjective evaluation of intercuspation and incisor occlusion of posttreatment study models and included 78 patients. Cephalometric characteristics or postretention occlusion was not considered in sample selection. The mode response was no change postretention for molar, premolar, and canine relationships and relapse of 0.5 mm for overjet and overbite. Maximum relapse was 3.5 mm for molar, premolar, and canine relationship, 3 mm for overjet, and 4.5 mm for overbite. Stepwise backward multiple regression analyses revealed no associations between either pretreatment characteristics or skeletal and dental treatment changes and relapse of overjet. However, relapse of overjet was associated with relapse of molar, premolar, and canine relationships, postretention increase in overbite, postretention proclination of maxillary incisors, and postretention retroclination of mandibular incisors. Active treatment changes included redirection or inhibition of maxillary growth and retraction of maxillary incisors. Mandibular incremental growth was favorable both during and after treatment. It was concluded that successful correction of Angle Class II, Division 1 malocclusions through differential growth adaptation and tooth movement appears to be very stable.

An investigation of maxillary superimposition techniques using metallic implants.

The purpose of this study was to determine if there are discernable, stable, anatomic landmarks in the maxilla that may reliably be used for maxillary superimposition. It was hypothesized that, through the evaluation of cephalometric radiographs of patients with metallic implants, such anatomic landmarks could be identified. The material for this study consisted of pairs of cephalometric radiographs from 50 subjects, 23 males and 27 females ages 8.7 to 20.3 years. All films were taken at least 3 years apart. The mean age at the time of the first film was 11.9 +/- 1.4 years, and the mean age at the time of the second film was 16.0 +/- 1.7 years. The two serial tracings from each subject were superimposed on the implants and evaluated for best fit of anatomic structures. The maximum distance that the structures varied from perfect superimposition was measured. Rotational changes of the maxilla relative to the cranial base and of the palatal plane relative to the maxilla were evaluated. In the vertical plane, the floor of the orbit raised more than the palatal plane lowered by an average ratio of 1.5 to 1 mm. The maxilla demonstrated varying degrees and directions of rotation relative to the cranial base. The palatal plane demonstrated varying degrees and directions of rotation within the maxilla. Internal structure of the palate was of limited value as a stable area of registration. Infraorbital foramen, PTM, ANS, PNS, A point, and superior and inferior borders of the palate were not found to be stable landmarks for maxillary superimposition.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Eruption of mandibular third molars after second-molar extractions: a radiographic study.

The purpose of the present study was to analyze the posteruptive contact relationship and inclination of mandibular third molars after extraction of second molars and to determine whether predictors could be formulated for the dental relationships observed. In all, 140 mandibular quadrants were evaluated from 95 sets of panoramic radiographs taken at the time of second molar extraction (T1) and at the time of final evaluation (T2). For analysis of a consecutive sample of patients, a subsample of 25 sets of radiographs from all the patients who had received such treatment during one calendar year was also quantified. Subjective evaluation indicated that 46% of the sites examined had satisfactory tooth contact relationship between the first and third molars at T2. Third-molar impaction was found in 4% of the sites in the subsample of 25 consecutively treated patients. Measurements of crown axis inclination revealed that the third molar invariably erupted into a mesially tilted position. The first molar showed only minor distal tipping between T1 and T2. Inclination of the third molar bud at the time of second molar extraction was not found to be a useful predictor for posteruptive third molar position. The clinical significance of these results and the need for studies regarding a rationale for mandibular second molar extraction are discussed.

A long-term study of the relationship of third molars to changes in the mandibular dental arch.

The purpose of this study is to determine the relationship of third molars to changes in the mandibular dental arch. The sample for this study consisted of four groups and subgroups. The groups consisted of premolar extraction treated, nonextraction treated with initial generalized spacing, nonextraction treated, and serial extraction untreated subjects. The subgroups were divided into persons who had mandibular third molars that were either impacted, erupted into function, congenitally absent, or extracted at least 10 years before postretention records. The mean postretention time interval was 13 years, with a range of 10 to 28 years. The mean postretention age was 28 years 6 months, with a range of 18 years 6 months to 39 years 4 months. Two-way analysis of variance with repeated measures was used to compare the changes over time (before treatment, at end of active treatment, and after retention) of groups and third molar subgroups. With time, mandibular incisor irregularity increased while arch length and intercanine width decreased. The eruption patterns of mandibular incisors and first molars were similarly dispersed in all groups studied. The findings between the subgroups in which mandibular third molars were impacted, erupted into function, congenitally absent, or extracted 10 years before postretention records revealed no significant differences between any of the subgroups for the parameters studied. No significant differences in mandibular growth were found between the third molar subgroups; this suggests that persons with third molars erupted into satisfactory function do not have a significantly different mandibular growth pattern than those whose third molars are impacted or congenitally missing. In the majority of cases some degree of mandibular incisor crowding took place after retention, but this change was not significantly different between third molar subgroups. This finding suggests that the recommendation for mandibular third molar removal with the objective of alleviating or preventing mandibular incisor irregularity may not be justified.

A comparison of apical root resorption during orthodontic treatment in endodontically treated and vital teeth.

The purpose of this study was to determine whether vital and endodontically treated incisors exhibit a similar severity of apical root resorption in response to orthodontic treatment. Forty-three patients who had one or more endodontically treated incisors before orthodontic treatment and who exhibited signs of apical root resorption after treatment were studied. In each patient the vital contralateral incisor served as a control. Vital incisors resorbed to a significantly greater degree than endodontically treated incisors (p less than or equal to 0.05). When patients were separated by gender, control teeth in males exhibited a statistically significant increase in resorption over control teeth in females. No significant differences were apparent between males and females when endodontically treated incisors were compared.

Long-term evaluation of root resorption occurring during orthodontic treatment.

The present study was undertaken to evaluate the long-term status of teeth that had undergone root resorption during active orthodontic treatment. A total of 100 patients who exhibited root resorption during appliance therapy were recalled at a mean period of 14.1 years (SD 0.4) after treatment. At those examinations full-mouth sets of periapical radiographs were taken and tooth mobility evaluated. Pretreatment, posttreatment, and long-term periapical radiographs were examined and compared for changes in root length and contour with time. At each stage scores were given on a scale from 0 to 4, depending on the degree of resorption. The maxillary incisors were affected more frequently and to a greater degree than the rest of the teeth during active treatment. The long-term evaluation showed no apparent changes after appliance removal except remodeling of rough and sharp edges. Hypermobility was observed in only two instances.

Long-term periodontal status of labially erupted canines following orthodontic treatment.

Periodontal status was studied at the mesiobuccal, midbuccal and distobuccal aspects of contralateral pairs of canines in 22 postorthodontic patients aged 30 to 51 years with a mean time of 26.4 years (SD, 5.6) out of active treatment. The pretreatment models showed one canine erupting severely to the labial ("ectopic") with a contralateral canine in good arch alignment (control). None of the patients experienced relapse of the "ectopic" canine in a labial direction, and none had missing teeth, malalignment, overhanging restorations or open tooth contacts adjacent to the canines evaluated. Periodontal parameters were examined using a Michigan #0 probe with Williams markings. A nonstandardized light force was used and the measurements were rounded to the nearest millimeter. The results demonstrated statistically significant differences between the canines in probing attachment and bone levels (mean, 0.75; SD, 0.92; P less than 0.01) and width of attached gingiva (mean, 0.50; SD, 1.07; p less than 0.05) at the midbuccal aspects. The reason for these differences could only be speculated upon.

Perceptions of facial profile and their influence on the decision to undergo orthognathic surgery.

Eighty patients, who had previously been evaluated by an oral surgeon and an orthodontist as requiring orthognathic surgery, completed questionnaires rating their perceptions of their own profiles. Half of the patients had decided to undergo surgical correction of their jaw deformities, while the other half had decided against surgical treatment. In addition, booklets containing pretreatment photographs of all 80 patients were mailed to 37 oral surgeons, 46 orthodontists, and 43 lay persons. These three groups of evaluators rated the patients' profiles, using the same rating scales that the patients had used. Cephalometrically, the two patient groups were statistically the same in all skeletal and soft-tissue measures except for ANB (mean difference = 1.8 degrees) and soft-tissue AN-pogonion (mean difference = 2.4 degrees). Differences in these dimensions were considered in subsequent data analyses. Results of this study support the following conclusions: In spite of the fact that surgical treatment may be recommended by dental specialists and indicated by cephalometric measurements, self-perceptions of profile are more important in the patient's decision to elect surgical correction; the perception by others that the profiles of patients deciding against surgery are closer to ideal may have some influence on their decision against surgical correction of their jaw deformities; oral surgeons and orthodontists evaluate facial profiles similarly, but surgeons are more likely to recommend surgical correction; lay persons are more likely to rate an individual's profile as being normal than are dental specialists in orthodontics and oral surgery; in contrast, individuals perceive their own profiles differently than orthodontists, oral surgeons, and lay persons, particularly with respect to the mandibular and dentoalveolar dimensions.

Anterior open-bite malocclusion: a longitudinal 10-year postretention evaluation of orthodontically treated patients.

Long-term response of the anterior open-bite malocclusion was evaluated in forty-one white subjects who had undergone orthodontic treatment and were out of retention a minimum of 9 years 6 months. The purpose of the study was threefold: (1) to make cephalometric comparisons between a sample of open-bite patients and a sample with normal cephalometric standards, (2) to evaluate treatment and posttreatment changes that occurred in treated open-bite patients, and (3) to search for predictors and associations of value. Changes occurring across time in the open-bite patients were analyzed by computer means using pretreatment, posttreatment, and long-term cephalometric radiographs and dental casts. An analysis of subgroups was reviewed to compare dentoalveolar and skeletal relationships of both stable and relapse groups. More than 35% of the treated open-bite patients demonstrated a postretention open bite of 3 mm or more, with the relapse subgroup demonstrating across-time, less mandibular anterior dental height, less upper anterior facial height, greater lower anterior facial height, and less posterior facial height. Neither the magnitude of pretreatment open bite, mandibular plane angle, nor any other single parameter of dentofacial form proved to be a reliable predictor of posttreatment stability.

Condylar position following mandibular advancement: its relationship to relapse.

Forty-one patients who elected to receive a bilateral sagittal osteotomy to advance the mandible were examined clinically and radiographically to assess condylar position preoperatively and at three specific times postoperatively. Parameters designed to measure changes in condylar and distal fragment position were located on tracings and digitized for statistical analysis. Changes in distal fragment position included advancement and clockwise rotation during the surgical interval and significant posterior relapse with continued clockwise rotation during the period of maxillomandibular fixation. A small amount of counterclockwise rotation associated with interocclusal splint removal was seen following fixation release. No significant condylar movement was seen during the surgical interval. During the period of maxillomandibular fixation, both condyles exhibited a significant superior movement, and the left condyle also moved posteriorly. No changes in condylar position were noted following release of fixation. The clinical significance of these condylar movements is not clear. Despite minimal changes, 18 patients, six of whom had had no preoperative symptoms and one of whom had exhibited reciprocal clicking, complained of temporomandibular joint pain or noise postoperatively. This suggests that maintenance of condylar position during surgery may not prevent temporomandibular joint dysfunction. In addition, the observed 37% relapse in surgical advancement in the absence of significant condylar distraction implies the interaction of other factors in the relapse process.

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.