Three-dimensional evaluation of dentopalatal changes after rapid maxillary expansion in growing children.

INTRODUCTION: In growing children with transverse malocclusion problems, various types of rapid maxillary expanders (RMEs) have been effectively used in skeletal and dental expansions. We evaluated 3-dimensional dentopalatal changes in growing children who underwent maxillary expansion using RMEs and bonded RMEs. METHODS: We investigated dentopalatal changes in 20 patients treated with bonded RMEs, 19 with RMEs, and 38 control patients. Dental plaster models before and after expansion were scanned 3-dimensionally and superimposed to evaluate transverse expansion, expansion ratio, angular expansion, and palatal expansion height ratio. RESULTS: Using bonded RMEs, similar anterior and posterior dental expansions were achieved with an efficiency of 69%-76% (expansion ratio), and palatal soft-tissue expansion occurred more apically in the posterior area (palatal expansion height ratio, 1.00) than in the anterior area (palatal expansion height ratio, 0.64). Using RMEs, a larger posterior dental expansion was achieved, with an efficiency of 106%-117% (expansion ratio), than anterior dental expansion (55%-60%), and palatal soft-tissue expansion occurred more apically in the posterior area (palatal expansion height ratio, 0.99) than anterior area (palatal expansion height ratio, 0.23). CONCLUSIONS: Dental expansions in the anterior and posterior areas were similar using bonded RMEs, whereas the posterior dental expansions were larger than those of the anterior area using RMEs. The entire palatal soft-tissue slope expanded in the posterior area, whereas the occlusal part expanded in the anterior area using RMEs and bonded RMEs.

Nonsurgical treatment of an adult with a skeletal Class III malocclusion combined with a functional anterior shift, severely overclosed vertical dimension, and a reverse smile.

This case report illustrates the successful nonsurgical treatment of an adult with a skeletal Class III malocclusion exacerbated by a functional anterior shift that resulted in a severe overclosure of the mandible and a reverse smile line. To maximize the soft tissue and smile esthetics while idealizing the occlusion, active clockwise rotation of the mandible was induced along with mandibular molar uprighting and sequential leveling. In the maxilla, full arch distalization was achieved after second molar extraction. The treatment provided a satisfying esthetic and functional outcome and has remained stable.

Dynamics of alveolar bone healing after the removal of orthodontic temporary anchorage devices.

OBJECTIVE: The aim of this study was to investigate the dynamics of alveolar bone formation and healing pattern after the removal of orthodontic temporary anchorage devices (TADs). METHODS: Miniscrews (N = 32) were inserted into the buccal inter-radicular alveolar bone in beagle dogs. Afterward, miniscrews were removed at different time points during a 13-week period and six different in vivo fluorescent markers were injected at 1, 2, 6, 8, 10, and 12 weeks. Serial changes in bone apposition at the removal and intact control sites were evaluated using µCT, histology, and bone histomorphometry. RESULTS: Gradual bone apposition at the TAD removal site was noted with bone volume/tissue volume (BV/TV) reaching the level of the control alveolar bone by 7 weeks. Histologically, newly formed woven bone was detected within the removal site which was distinct from the surrounding pre-existing alveolar bone at 13 weeks. Accelerated mineral apposition rate (MAR) and bone formation rate (BFR) were noted between 2 and 6 weeks in the removal site (P < 0.05). Although MAR and BFR gradually decreased after its peak at 2-4 weeks, BFR in the removal site was still higher than the control site at 10-12 weeks (P < 0.05). CONCLUSIONS: Spontaneous bone healing was noted after TAD removal with regional acceleration of MAR and BFR within 2-6 weeks. However, the removal site was mainly filled with woven bone even after 13 weeks, suggesting a longer healing period is required for the quality of the alveolar bone to reach levels comparable to the surrounding alveolar bone.

Diagnosis and Surgical Outcomes of Facial Asymmetry According to the Occlusal Cant and Menton Deviation.

PURPOSE: Morphologic differences and surgical outcomes were compared between the ipsilateral type of facial asymmetry, in which the menton deviates to the side of the upward frontal occlusal plane (FOP) cant (FOPUP), and the contralateral type, in which the menton deviates to the side of the downward FOP cant (FOPDOWN), by using cone beam computed tomography (CBCT) images. MATERIALS AND METHODS: This retrospective study included consecutive patients with skeletal Class III malocclusion and facial asymmetry who had undergone bimaxillary orthognathic surgery and serial CBCT before, 1 month after, and 1 year after surgery. CBCT images were reconstructed and analyzed for predictor (group and timing) and outcome (CBCT measurements over time) variables. The data were analyzed using independent t tests and paired t tests. RESULTS: The contralateral group (n = 12) was selected first; the ipsilateral group (n = 12) was selected by matching age, gender, and degree of FOP cant with those of the contralateral group. Before surgery, in the ipsilateral group, the ramal length was longer on the nondeviated (N-Dev) side than on the deviated (Dev) side (P < .05) whereas the mandibular body length showed no significant difference (P > .05). In the contralateral group, the ramal length was longer on the Dev side (P < .05) whereas the mandibular body length was longer on the N-Dev side (P < .01). One year after surgery, most measurements were corrected symmetrically in both groups (P > .05); however, the hemi-lower facial area remained asymmetrical in the contralateral group (P < .05). CONCLUSIONS: Differences in ramal lengths in the ipsilateral group and mandibular body lengths in the contralateral group between the Dev and N-Dev sides seemed to be the main cause of facial asymmetry. Although facial asymmetry improved after surgery in both groups, asymmetry in the soft tissue remained in the contralateral group 1 year after surgery.

A longitudinal comparison of body height growth of orthodontically treated Class I and Class III adolescents compared with the general population.

INTRODUCTION: The aim of this study was to evaluate the height growth of Class I and III orthodontic patients according to the Fishman skeletal maturation index (SMI) and to compare it with that of a general population. METHODS: The study sample included 81 Class I and 71 Class III adolescents who had height measurements and hand-wrist radiographs taken annually and categorized according to SMI. Height completion rate, residual height, height increase per sequential SMI stage, and height velocity were analyzed. Sex differences were evaluated and comparisons between Class I and Class III groups were made. In addition, the height of orthodontic patients was indirectly compared with that of the general population. RESULTS: In boys and girls, height completion rate was >90% at SMI 6, residual height was fewer than 10 cm at SMI 7, and height increase per sequential SMI stage was greatest from SMI 6 to SMI 7. Height velocity was greatest from SMI 5 to SMI 6 in boys and from SMI 4 to SMI 5 in girls. CONCLUSIONS: There was no significant difference in body height parameters for all SMI stages between Class I and Class III adolescents. Adolescents who had orthodontic treatment were not shorter in stature at growth completion compared with the general population.

Anchorage loss assessment of the indirect anchor tooth during adjunctive orthodontic treatment.

INTRODUCTION: This study quantitatively assessed movement of anchor teeth connected to a miniscrew (indirect anchor tooth) and investigated factors affecting movement during adjunctive orthodontic treatment. METHODS: Dental plaster models of 28 patients whose treatment included an indirect anchor tooth on one side were collected before and after treatment. The casts were digitally scanned, and 2 groups were constituted: the indirect anchor teeth (experimental group; n = 52) and the untreated teeth (control group; the first and second premolars opposing the indirect anchor tooth to which no orthodontic force was applied; n = 55). Pretreatment and posttreatment models were superimposed and the amount and direction of indirect anchor tooth movement were evaluated with the use of a univariate linear mixed model. Possible factors affecting movement of the indirect anchor tooth and its significance were also evaluated with the use of a multiple linear mixed model. RESULTS: The indirect anchor tooth moved 0.91 ± 0.50 mm and did not exhibit significant differences in the transverse, vertical, or sagittal directions. The location of the indirect anchor tooth affected movement and the tooth moved significantly more in the mandible than in the maxilla. CONCLUSIONS: The indirect anchor tooth can move during adjunctive orthodontic treatment and thus requires careful monitoring for occlusal changes.

Spontaneous repair of iatrogenic root perforation by an orthodontic miniscrew: A case report.

BACKGROUND AND OVERVIEW: Orthodontic miniscrews have become popular tools for providing temporary anchorage during orthodontic treatment. Although they are easy to insert, damage to the periodontal ligament or dental root during insertion is an unfavorable iatrogenic complication. Root perforation during miniscrew insertion in human teeth has been reported in a few articles. In this article, the authors describe the spontaneous repair of an iatrogenic root perforation in a mandibular first molar that occurred during insertion of an orthodontic miniscrew in a young girl undergoing orthodontic treatment. CASE DESCRIPTION: A 15-year-old girl with malocclusion was undergoing orthodontic treatment when the mesial root of her mandibular right first molar was damaged by an orthodontic miniscrew. The miniscrew and corresponding bracket were immediately removed to avoid any unnecessary forces on the tooth. Because the pulp remained vital without any additional damage and infection for 6 months, orthodontic treatment was resumed and completed in 9 months without any pulp damage or unfavorable symptoms. Serial periapical radiographs and cone-beam computed tomographic images showed that the injured area was surrounded by reparative tissue without any apical lesion. CONCLUSIONS AND PRACTICAL IMPLICATIONS: The findings of this case suggest that immediate removal of unnecessary forces provides an environment for spontaneous repair in cases of iatrogenic root perforation by orthodontic miniscrews, even when the damage involves the pulp. If force stimulation is avoided for a certain period, which was 6 months in this case, it may be possible to complete the orthodontic treatment without unfavorable symptoms.

Differences in mandibular condyle and glenoid fossa morphology in relation to vertical and sagittal skeletal patterns: A cone-beam computed tomography study.

OBJECTIVE: This study aimed to evaluate the following null hypothesis: there are no differences in the morphology of the temporomandibular joint (TMJ) structures in relation to vertical and sagittal cephalometric patterns. METHODS: This retrospective study was performed with 131 participants showing no TMJ symptoms. The participants were divided into Class I, II, and III groups on the basis of their sagittal cephalometric relationships and into hyperdivergent, normodivergent, and hypodivergent groups on the basis of their vertical cephalometric relationships. The following measurements were performed using cone-beam computed tomography images and compared among the groups: condylar volume, condylar size (width, length, and height), fossa size (length and height), and condyle-to-fossa joint spaces at the anterior, superior, and posterior condylar poles. RESULTS: The null hypothesis was rejected. The Class III group showed larger values for condylar width, condylar height, and fossa height than the Class II group (p < 0.05). Condylar volume and superior joint space in the hyperdivergent group were significantly smaller than those in the other two vertical groups (p < 0.001), whereas fossa length and height were significantly larger in the hyperdivergent group than in the other groups (p < 0.01). The hypodivergent group showed a greater condylar width than the hyperdivergent group (p < 0.01). The sagittal and vertical cephalometric patterns showed statistically significant interactions for fossa length and height. CONCLUSIONS: TMJ morphology differed across diverse skeletal cephalometric patterns. The fossa length and height were affected by the interactions of the vertical and sagittal skeletal patterns.

Differential alveolar bone modeling after orthodontic retraction.

BACKGROUND: Distinct, irregular, and hard nodular protuberances similar to the morphologic features of exostoses can occasionally be noted on the labial surface of the alveolar bone after orthodontic retraction of anterior teeth in adults. These have long been believed to be exostoses developed in response to loading. However, specific characterization of this phenomenon has not been documented. CASE DESCRIPTIONS: Three cases of patients displaying multiple irregular labial bony protuberances after retraction of anterior teeth are reported. These protuberances appeared during retraction and became more prominent with additional retraction. Serial clinical photographs, lateral cephalograms, digital models, and cone-beam computed tomography scans were evaluated. On the basis of 3-dimensional superimpositions of digital models and cone-beam computed tomographic scans, the irregular protuberances appear to be the result of differential alveolar bone modeling, with more resorption of bone covering the tooth root than that of interdental bone, and not of true bone overgrowth or deposition (that is, exostoses). CONCLUSION AND PRACTICAL IMPLICATIONS: Orthodontic patients often seek treatment to improve occlusion as well as esthetics. Although this study shows that these protuberances are the result of differential modeling, they may still be perceived by patients as "outgrowths," which may cause concerns related to esthetics or comfort. Clinicians should note that these protuberances are a possible outcome when large amounts of bodily retraction and root movement of anterior teeth are planned. Patients who experience psychosocial problems with this phenomenon may be candidates for alveoloplasty.

A 15-year follow up of an orthodontic treatment including a lower incisor extraction and keeping the maxillary canine-premolar transposition.

Lower incisor extraction is an effective option for treating lower anterior crowding in patients with a good facial profile, Class I molar occlusion, and narrow upper incisors. This report describes the successful treatment of an adolescent patient with lower anterior crowding and a transposed maxillary canine and premolar treated by extracting a lower incisor and keeping the transposed positions of the teeth. With the use of retainers, treatment results were stable up to the 2-year postretention visit. However, upon a 15-year postretention appointment, the fixed retainer had been removed and the removable retainer was no longer in use, which resulted in relapse of lower anterior alignment. Moreover, the transposed canine had extruded during this period, causing occlusal interference and gingival recession, as well as loss of tooth vitality, which indicates the importance of maintaining orthodontic retainers for long-term stable occlusion.

Assessment of lower incisor alveolar bone width using cone-beam computed tomography images in skeletal Class III adults of different vertical patterns.

OBJECTIVE: This study was performed to investigate the alveolar bone of lower incisors in skeletal Class III adults of different vertical facial patterns and to compare it with that of Class I adults using cone-beam computed tomography (CBCT) images. METHODS: CBCT images of 90 skeletal Class III and 29 Class I patients were evaluated. Class III subjects were divided by mandibular plane angle: high (SN-MP > 38.0°), normal (30.0° < SN-MP < 37.0°), and low (SN-MP < 28.0°) groups. Buccolingual alveolar bone thickness was measured using CBCT images of mandibular incisors at alveolar crest and 3, 6, and 9 mm apical levels. Linear mixed model, Bonferroni post-hoc test, and Pearson correlation analysis were used for statistical significance. RESULTS: Buccolingual alveolar bone in Class III high, normal and low angle subjects was not significantly different at alveolar crest and 3 mm apical level while lingual bone was thicker at 6 and 9 mm apical levels than on buccal side. Class III high angle group had thinner alveolar bone at all levels except at buccal alveolar crest and 9 mm apical level on lingual side compared to the Class I group. Class III high angle group showed thinner alveolar bone than the Class III normal or low angle groups in most regions. Mandibular plane angle showed negative correlations with mandibular anterior alveolar bone thickness. CONCLUSIONS: Skeletal Class III subjects with high mandibular plane angles showed thinner mandibular alveolar bone in most areas compared to normal or low angle subjects. Mandibular plane angle was negatively correlated with buccolingual alveolar bone thickness.