The short-term treatment effects of face mask therapy in Class III patients based on the anchorage device

Abstract Objective: To compare the short-term treatment effects of face mask therapy with miniplates (FM-MP) and face mask therapy with rapid maxillary expansion appliance (FM-RME) in growing Class III malocclusion patients with maxillary hypoplasia. Materials and Methods: Twenty patients were allocated into two groups according to the anchorage device: FM-MP group (n = 10; mean age = 11.2 ± 1.2?years; miniplates in the zygomatic buttress area) and FM-RME group (n = 10; mean age = 10.7 ± 1.3?years; bonded or banded RME). The face mask was applied for 12 to 14?hours/day in both groups with a force of 400?g/side directed 30° downward and forward from the occlusal plane. Lateral cephalograms were taken before (T1) and after FM-MP or FM-RME therapy (T2). Skeletodental and soft-tissue variables were measured. Paired and independent t-tests were performed for statistical analysis. Results: Both groups exhibited significant forward movement of point A and posterior repositioning and opening rotation of the mandible from T2 to T1. The FM-MP group showed significant protraction of orbitale (ΔSNO), and the FM-RME group showed a decrease in overbite and an increase in Bj?rk sum. Comparing the amount of changes between the two groups, the FM-MP group displayed greater forward movement of the maxilla than the FM-RME group (ΔSNA, ΔA to N perp, all P < .05). However, the FM-RME group exhibited a greater opening rotation of the mandible (ΔSNB, Bj?rk sum, all P < .01; ΔPog to N-perp, P < .05) and labioversion of the maxillary incisors (ΔU1-FH, P < .05). Conclusion: FM-MP therapy induces a greater advancement of the maxilla, less posterior repositioning and opening rotation of the mandible, and less proclination of the maxillary incisors than FM-RME therapy.     

Maxillary incisor inclination of skeletal Class III patients treated with extraction of the upper first premolars and two-jaw surgery: Conventional orthognathic surgery vs surgery-first approach

Objective:To investigate the differences in the amount and pattern of the maxillary incisor (MXI) inclination change in skeletal Class III patients treated with extraction of the maxillary first premolars (MXP1) and two-jaw surgery (TJS) between conventional orthognathic surgery (COS) and surgery-first approach (SFA).Materials and Methods:The study included 60 skeletal Class III patients who had normal maxillary position, prognathic mandible, and mild crowding in the maxillary arch (≤4 mm). The patients were divided into group 1 (COS, n  =  36) and group 2 (SFA, n  =  24). Lateral cephalograms were taken before treatment (T0), 1 month before surgery (T1), within 1 month after surgery (T2), and after debonding (T3) for COS patients and at T0, T2, and T3 for SFA patients. After measurement of the skeletodental variables, statistical analyses were performed.Results:During T0–T2, the amount of MXI inclination change (ΔU1-SN) in group 1 was significantly larger than that in group 2 (−12.8° vs −4.4°; P < .001). During T2–T3, ΔU1-SN in groups 1 and 2 occurred in opposite directions (3.8° vs −5.9°; P < .001). However, the total amount of ΔU1-SN during T0–T3 was not different between groups 1 and 2 (−9.0° vs −10.3°). At T3 the U1-SN values for groups 1 and 2, respectively, moved closer to normal according to the values of the normal range rate (all 83%), relative percentage ratio (102.4% and 100.1%), and achievement ratio (77.7% and 97.8%).Conclusions:The results of this study might provide basic data for predicting the amount and pattern of MXI inclination change in SFA for skeletal Class III TJS patients.     

Evaluation of canting correction of the maxillary transverse occlusal plane and change of the lip canting in Class III two-jaw orthognathic surgery

Objective:To compare the effect of canting correction in anterior maxillary transverse occlusal planes (AMTOP) and posterior maxillary transverse occlusal planes (PMTOP) on the change of lip canting (LC) in two-jaw surgery (TJS) cases.Materials and Methods:The samples consisted of eight young adult patients (three males and five females, mean age  =  24.1 ± 4.5 years) who had skeletal Class III malocclusion (CIII), facial asymmetry (FA), and LC and who underwent TJS. Two-dimensional lateral and posteroanterior cephalograms and three-dimensional facial scanning taken 1 week before (T1) and 6 months after TJS (T2) were combined using the Morpheus 3D program. Six linear and angular variables were measured and statistically analyzed.Results:When comparing the values of the linear and angular variables at the T1 and T2 stages there was significant canting correction of AMTOP (1.7 mm vs −0.3 mm; 3.0° vs 0.1°), PMTOP (3.5 mm vs 0.1 mm, 3.3° vs −0.1°), and LC (3.0 mm vs 0.7 mm, 4.7° vs 2.1°) (all P < .05). Although the angular change ratios (ΔLC/ΔAMTOP and ΔLC/ΔPMTOP) did not exhibit a significant difference (0.99 vs 0.83), the linear change ratio of ΔLC/ΔAMTOP was significantly higher than that of ΔLC/ΔPMTOP (1.67 vs 0.74, P < .05). The angular change of ΔLC showed a significant correlation with ΔAMTOP (r²  =  0.64; P < .05). However, the linear change of ΔLC was significantly correlated with both the angular and linear changes of ΔAMTOP (r²  =  0.62 and 0.66; both P < .05). Therefore, the amount of LC change was more related to the canting correction of AMTOP than to that of PMTOP.Conclusion:In TJS cases with CIII, FA, and LC, the amount of canting correction of the AMTOP should be considered to predict the actual LC change.     

Asymmetric rapid maxillary expansion in true unilateral crossbite malocclusion: A prospective controlled clinical study

Objective:To investigate the short-term effects of the asymmetric rapid maxillary (ARME) appliance on the vertical, sagittal, and transverse planes in patients with true unilateral posterior crossbite.Materials and Methods:Subjects were divided into two groups. The treatment group was comprised of 21 patients with unilateral posterior crossbite (mean age  =  13.3 ± 2.1 years). Members of this group were treated with the ARME appliance. The control group was comprised of 17 patients with Angle Class I who were kept under observation (mean age  =  12.3 ± 0.8 years). Lateral and frontal cephalograms were taken before the expansion (T1), immediately after expansion (T2), and at postexpansion retention (T3) in the treatment group and at preobservation (T1) and postobservation (T2) in the control group. A total of 34 measurements were assessed on cephalograms. For statistical analysis, the Wilcoxon test and analysis of covariance were used.Results:The ARME appliance produced significant increases in nasal, maxillary base, upper arch, and lower arch dimensions (P < .01) and a clockwise rotation of the occlusal plane (P  =  .001).Conclusion:The ARME appliance created asymmetric increments in the transversal dimensions of the nose, maxilla, and upper arch in the short term. Asymmetric expansion therapy for subjects with unilateral maxillary deficiency may provide satisfactory outcomes in adolescents, with the exception of mandibular arch expansion. The triangular pattern of expansion caused clockwise rotation of the mandible and the occlusal plane and produced significant alterations in the vertical facial dimensions, whereas it created no displacement in maxilla in the sagittal plane.     

Evaluation of the effects of skeletal anchoraged Forsus FRD using miniplates inserted on mandibular symphysis: A new approach for the treatment of Class II malocclusion

Objective:To evaluate the skeletal, dentoalveolar, and soft tissue effects of the Forsus Fatigue Resistant Device (FRD) appliance with miniplate anchorage for the treatment of skeletal Class II malocclusion.Material and Methods:The prospective clinical study group included 17 patients (11 girls and 6 boys; mean age 12.96 ± 1.23 years) with Class II malocclusion due to mandibular retrusion and treated with skeletal anchoraged Forsus FRD. After 0.019 × 0.025-inch stainless steel archwire was inserted and cinched back in the maxillary arch, two miniplates were placed bilaterally on the mandibular symphysis. Then, the Forsus FRD EZ2 appliance was adjusted to the miniplates without leveling the mandibular arch. The changes in the leveling and skeletal anchoraged Forsus FRD phases were evaluated by means of the Paired and Student''s t-tests using the cephalometric lateral films.Results:The success rate of the miniplates was found to be 91.5% (38 of 42 miniplates). The mandible significantly moved forward (P < .001) and caused a significant restraint in the sagittal position of the maxilla (P < .001). The overjet correction (−5.11 mm) was found to be mainly by skeletal changes (A-VRL, −1.16 mm and Pog-VRL, 2.62 mm; approximately 74%); the remaining changes were due to the dentoalveolar contributions. The maxillary and mandibular incisors were significantly retruded (P < .001).Conclusion:This new approach was an effective method for treating skeletal Class II malocclusion due to the mandibular retrusion via a combination of skeletal and dentoalveolar changes.     

Comparison of tooth development stage of the maxillary anterior teeth before and after secondary alveolar bone graft: Unilateral cleft lip and alveolus vs unilateral cleft lip and palate

Objective:To compare the effect of secondary alveolar bone graft (SABG) on the tooth development stage of the maxillary central incisor (MXCI) and maxillary canine (MXC) in terms of the severity of unilateral cleft.Materials and Methods:The subjects consisted of 50 boys with unilateral cleft lip and alveolus (UCLA) or unilateral cleft lip, alveolus, and palate (UCLP). The age- and sex-matched subjects were divided into group 1 (UCLA, n = 25; 9.3 ± 0.8 years old) and group 2 (UCLP, n = 25; 9.4 ± 0.6 years old). In panoramic radiographs taken 1 month before (T0) and 1 year after SABG (T1), tooth development stage was evaluated according to the Nolla developmental (ND) stage. A panoramic radiograph taken 3 years after SABG was used as a reference for the final root length of individual tooth.Results:In groups 1 and 2, the ND stage of the MXCI did not exhibit differences between the cleft and non-cleft sides at T0 and T1, respectively. However, although the ND stage of the MXC of group 2 was delayed on the cleft side compared with the non-cleft side at T0 (P < .05), the MXC on the cleft side developed faster than that on the non-cleft side after SABG (P < .01). In terms of tooth development speed, group 2 showed a higher rate of faster developed MXCs on the cleft side compared with the non-cleft side after SABG than group 1 (36.0% vs 8.0%, P < .05).Conclusion:SABG performed at approximately 9 years of age might increase tooth development speed of MXC in patients with UCLP compared with patients with UCLA.     

Tooth-borne vs bone-borne rapid maxillary expanders in late adolescence

Objective:To evaluate the immediate effects of rapid maxillary expansion (RME) on the transverse skeletal and dentoalveolar changes with bone-borne (C-expander) and tooth-borne type expanders using cone-beam computed tomography (CBCT) in late adolescents.Materials and Methods:A sample of 28 female late-adolescent patients was divided into two groups according to the type of expander: bone-borne (C-expander, n  =  15, age  =  18.1 ± 4.4 years) and tooth-borne (hyrax, bands on premolars and molars, n  =  13, age  =  17.4 ± 3.4 years). CBCT scans were taken at 0.2-mm voxel size before treatment (T1) and 3 months after RME (T2). Transverse skeletal and dental expansion, alveolar inclination, tooth axis, vertical height of tooth, and buccal dehiscence were evaluated on maxillary premolars and molars. Paired t-test, independent t-test, one-way analysis of variance, and Scheffé post hoc analysis were performed.Results:The C-expander group produced greater skeletal expansion, except in the region of the first premolar (P < .05 or < .01), which showed slight buccal tipping of the alveolar bone. The Hyrax group had more buccal tipping of the alveolar bone and the tooth axes, except in the region of the second molar (P < .05 or < .01 or < .001). Dental expansion at the apex level was similar in the banded teeth (the first premolar and the first molar). Vertical height changes were apparent on the second premolar in the hyrax group (P < .05 or < .01). Significant buccal dehiscence occurred at the first premolar in the hyrax group (P < .01 or < .001). There were no significant differences between tooth types for any variables in the C-expander group.Conclusions:For patients in late adolescence, bone-borne expanders produced greater orthopedic effects and fewer dentoalveolar side effects compared to the hyrax expanders.     

Response of the maxillary dentition to a statically determinate one-couple system with tip-back mechanics: A prospective clinical trial

Objective:To quantify the effects of tip-back mechanics on the maxillary first molars and incisors.Materials and Methods:Sixteen subjects with Class II end-on malocclusion were treated with an intrusion arch to achieve distalization of the maxillary molar through tip-back mechanics. Lateral cephalograms were taken prior to molar tip-back (T1), after molar tip-back (T2), and after molar root uprighting (T3). Data were analyzed using the Friedman’s and Wilcoxon signed rank tests to evaluate differences in time points (P ≤ .016).Results:The maxillary first molar distalized 1.53 mm (P = .001) with 6.65° (P = .001) of distal tipping and 0.86 mm (P = .001) of extrusion at T2. Minor relapse of the first molar (mesial direction) was seen at T3. The maxillary incisors flared labially 0.4 mm, and the incisor root apex moved palatally 1.19 mm (P = .005) at T2. At T3, the incisor root apex moved palatally 1.5 mm (P = .003) from T1. An angular change from T1 of 3.31° (P = .008) and 3.53° (P = .014) was seen at T2 and T3, respectively, as a result of palatal root movement of the maxillary incisors.Conclusions:A significant amount of distalization of maxillary molars was attained at the crown level with tip-back mechanics. Palatal root angulation change was significant in the incisors with minimal anteroposterior movement of the incisal edge.     

Comparison of pharyngeal airway volume among different vertical skeletal patterns: A cone-beam computed tomography study

Objective:To test the null hypothesis that there are no significant differences in pharyngeal airway volumes among adult patients with different vertical skeletal patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT).Material and Methods:The study sample consisted of 100 adult patients (45 men and 55 women; mean age  =  24.0 ± 5.3 years) with a normal sagittal skeletal pattern divided into three groups according to the vertical skeletal patterns: high angle (32 patients: 15 women and 17 men), low angle (34 patients: 14 women and 20 men), and normal angle (34 patients: 16 women and 18 men) groups. Nasopharyngeal, oropharyngeal, and total airway volumes of patients in all vertical groups were calculated. Group differences were analyzed using one-way analysis of variance and post hoc Tukey tests.Results:Nasopharyngeal airway volume in the high-angle group (mean  =  6067.9 ± 1693.9 mm³) was significantly lower than that of the low- and normal-angle groups (P < .01). Oropharyngeal airway volume was highest in the low-angle group (mean  =  15,957.6 ± 6817.2 mm³) and significantly decreased in the control (mean  =  11,826.1 ± 4831.9 mm³; P  =  .008) and high angle (mean  =  10,869.1 ± 4084.1 mm³; P  =  .001) groups. Total airway volume was highest in the low-angle group (mean  =  24,261.6 ± 8470.1 mm³) and lowest in the high-angle group (mean  =  16,937.0 ± 5027.4 mm³; P < .001).Conclusion:The null hypothesis was rejected. Significant differences were found in pharyngeal airway volumes among different skeletal vertical patterns.     

Maxillary anterior alignment stability in Class I and Class II malocclusions treated with or without extraction

Objective:To compare the postretention stability of maxillary incisors alignment in subjects with Class I and II malocclusion treated with or without extractions.Materials and Methods:The sample comprised 103 subjects with initial maxillary anterior irregularity greater than 3 mm and was divided into four groups: group 1 comprised 19 patients with Class I malocclusion treated with nonextraction (mean initial age = 13.06 years); group 2 comprised 19 patients with Class II malocclusion treated with nonextraction (mean initial age = 12.54 years); group 3 comprised 30 patients with Class I malocclusion treated with extractions (mean initial age = 13.16 years); group 4 comprised 35 patients with Class II malocclusion treated with extractions (mean initial age = 12.99 years). Dental casts were obtained at three different stages: pretreatment (T1), posttreatment (T2), and long-term posttreatment (T3). Maxillary incisor irregularity and arch dimensions were evaluated. Intergroup comparisons were performed by one-way analysis of variance followed by Tukey tests.Results:In the long-term posttreatment period, relapse of maxillary crowding and arch dimensions was similar in all groups.Conclusion:Changes in maxillary anterior alignment in Class I and Class II malocclusions treated with nonextractions and with extractions were similar in the long-term posttreatment period.     

Prediction of mandibular movement and its center of rotation for nonsurgical correction of anterior open bite via maxillary molar intrusion

Objectives:To evaluate quantitatively the relationship between molar intrusion (change [Δ] maxillary first molar [U6]–palatal plane [PP]) and changes in vertical and sagittal cephalometric parameters and to determine the center of mandibular autorotation.Materials and Methods:Twenty-one patients diagnosed with anterior open bite and successfully treated with molar intrusion (overbite [OB] > 0 mm) were retrospectively enrolled. Lateral cephalograms taken before and after molar intrusion were used to measure changes in vertical and sagittal cephalometric parameters. The center of mandibular autorotation was calculated by measuring displacement of gonion (Go) and pogonion (Pog). Paired t-tests were used to compare variables, and linear regression analysis was used to examine the relationship between ΔU6-PP and other variables.Results:The mandible exhibited counterclockwise rotation after maxillary molar intrusion, which led to closure of anterior open bite. Strong linear relationships, in descending order, between ΔU6-PP and ΔOB, Δanterior facial height (AFH), Δvertical reference plane (Pog), and Δsella-nasion to Go-menton (SN-GoMe), were observed. When the maxillary molar was intruded 1 mm, OB increased by 2.6 mm, AFH decreased by 1.7 mm, Pog moved forward by 2.3 mm, and SN-GoMe decreased by 2°. The center of mandibular autorotation was located 7.4 mm behind and 16.9 mm below condylion after molar intrusion.Conclusions:The mandible exhibited counterclockwise rotation after maxillary molar intrusion; the center of mandibular autorotation was located behind and below condylion with individual variations.     

Three-dimensional analysis of molar compensation in patients with facial asymmetry and mandibular prognathism

Objective:To evaluate the characteristic transverse dental compensations in patients with facial asymmetry and mandibular prognathism and to compare features of dental compensations between two types of mandibular asymmetry using 3-dimensional (3D) cone-beam computed tomography (CBCT).Materials and Methods:Seventy-eight adult patients with skeletal Class I (control group; n  =  33; 19 men and 14 women) or skeletal Class III with facial asymmetry (experimental group; n  =  45; 23 men and 22 women) were included. The experimental group was subdivided into two groups according to the type of mandibular asymmetry: translation type (T-type; n  =  20) and roll type (R-type; n  =  19). CBCT images were acquired before orthodontic treatment and 3D analyses were performed.Results:The transverse dental distance was significantly different between the two groups only at the palatal root apex of the maxillary first molar (P < .05). In the experimental group, the first molar axes were compensated significantly on both arches except the maxillary nondeviated side. The vertical molar heights were different between the two groups only on the maxillary arch (P < .001). The R-type showed greater mandibular ramal length difference and menton deviation than the T-type (P < .001). In the R-type, transverse compensation of the maxillary first molars was more obvious than with the T-type, which resulted in canting in the maxillary occlusal plane.Conclusions:Mandibular asymmetry with prognathism showed a characteristic transverse dental compensation pattern. The mandibular asymmetry type influenced the amount and direction of molar compensation on the maxillary arch.     

Comparison of transverse analysis between posteroanterior cephalogram and cone-beam computed tomography

Objectives:To evaluate maxillary and mandibular alveolar and basal bone widths using cone-beam computed tomography (CBCT) and to verify the correlation between CBCT images and posteroanterior (PA) cephalograms.Materials and Methods:The CBCT scans and PA cephalograms were obtained from 20 men (age range  =  24.0–29.1 years; mean age  =  27.2 years; SD  =  2.8 years) and 20 women (age range  =  20.3–28.1 years; mean age  =  26.4 years; SD  =  3.2 years) with normal occlusion. On CBCT images, maxillary and mandibular bone widths were measured at three posterior sites and five bone levels. The differences between maxillary and mandibular bone widths were calculated and compared with conventional transverse width of PA cephalograms.Results:Statistically significant differences in maxillary and mandibular bone widths were detected at different levels and sites. Bone widths were significantly increased from the alveolar crest toward the basal bone in the maxillary molar and mandibular second premolar and molar areas. A statistically significant correlation was only found between CBCT images and PA cephalograms for maxillomandibular width at the first molar area.Conclusion:The results of this study suggested that three-dimensional assessment of maxillomandibular width is mandatory for the transverse analysis.     

Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients

Objective:To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction.Materials and Methods:Panoramic radiographs of 21 Class II subdivision adolescents (eight boys, 13 girls; mean age, 12.8 years; standard deviation, 1.7 years) before treatment, after treatment with extraction of one maxillary first molar and Begg appliances and after at least 1.8 years in retention were retrospectively collected from a private practice. M2 and M3 inclination angles (M2/ITP, M2/IOP, M3/ITP, M3/IOP), constructed by intertuberosity (ITP) and interorbital planes (IOP), were calculated for the extracted and nonextracted segments. Random effects regression analysis was performed to evaluate the effect on the molar angulation of extraction, time, and gender after adjusting for baseline measurements.Results:Time and extraction status were significant predictors for M2 angulation. M2/ITP and M2/IOP decreased by 4.04 (95% confidence interval [CI]: −6.93, 1.16; P  =  .001) and 3.67 (95% CI: −6.76, −0.58; P  =  .020) in the extraction group compared to the nonextraction group after adjusting for time and gender. The adjusted analysis showed that extraction was the only predictor for M3 angulation that reached statistical significance. M3 mesial inclination increased by 7.38° (95% CI: −11.2, −3.54; P < .001) and 7.33° (95% CI: −11.48, −3.19; P  =  .001).Conclusions:M2 and M3 uprighting significantly improved in the extraction side after orthodontic treatment with unilateral maxillary M1 extraction. There was a significant increase in mesial tipping of maxillary second molar crowns over time.     

CBCT of skeletal changes following rapid maxillary expansion to increase arch-length with a development-dependent bonded or banded appliance

Objective:To assess the three-dimensional (3D) skeletal response to a standardized 5 mm of rapid maxillary expansion (RME) in growing children (6–15 years) with maxillary width deficiency and crowding.Materials and Methods:A bonded appliance was used prior to the eruption of the maxillary first premolars (Mx4s), and a banded appliance was used thereafter. A consecutive sample of 89 patients (29 boys and 60 girls) from a large pediatric dentistry and orthodontics practice was divided into four groups: 1) 6–8 years old (n  =  26), 2) 9–11 years old with unerupted Mx4s (n  =  21), 3) 9–11 years with erupted Mx4s (n  =  23), and 4) 12–15 years (n  =  19). For all patients, the 3D evaluation of dental and skeletal effects was performed with cone-beam computed tomography (CBCT).Results:For both appliances in all patients, CBCT confirmed a triangular pattern of expansion in both the frontal and sagittal planes. Overall, both appliances produced significant maxillary expansion (>80% of the 5-mm activation), but older children showed a progressively more dental (less skeletal) response. Comparison of the two types of expanders in the crossover sample, children aged 9–11 years, showed that the bonded RME produced the most efficient skeletal expansion in the preadolescent sample. Increased maxillary width at the level of the zygomaticomaxillary suture was the best indicator for development of maxillary arch circumference.Conclusion:Development-dependent appliances (bonded RPE before Mx4s erupt, and a banded device thereafter) provided optimal RME treatment for all children from age 6–15 years.     

Effects of face mask treatment with and without rapid maxillary expansion in young adult subjects

Objectives:To investigate the skeletal, dental, and soft tissue effects of the face mask (FM) treatment with and without rapid maxillary expansion (RME) in young adult subjects with maxillary retrognathia.Materials and Methods:Pretreatment and posttreatment cephalometric radiographs from 32 subjects who had a skeletal Class III malocclusion were analyzed. The subjects were divided into two groups: FM group (N  =  17; 3 male and 14 female subjects; mean [SD] age 14.47 [0.89] years) was treated with FM only, while the RME+FM group (N  =  15; 3 male and 12 female subjects; mean [SD] age 14.67 [1.28] years) was treated with both FM and RME. Ten cephalometric linear and nine angular variables were measured to assess dentofacial changes. Within-group and between-group comparisons were determined by a paired t-test and Student''s t-test, respectively.Results:Forward displacement of the maxilla and a clockwise rotation of the mandible occurred in both groups. The maxillary-mandibular relationship improved and soft tissue changes resulted in a more convex profile. The maxillary incisors were more proclined in the FM group than in the RME+FM group, the only difference between the two groups. Notably, the mandibular incisors moved backward in both groups.Conclusions:Forward movement of the maxilla can be obtained in young adults after face mask treatment. However, there was no difference in this phenomenon between the FM and RME+FM groups.     

Dentoskeletal changes following mini-implant molar intrusion in anterior open bite patients

Objective:To evaluate skeletal and dental changes after intrusion of the maxillary molars in subjects with anterior open bite.Materials and Methods:This retrospective cephalometric study evaluated skeletal and dental changes resulting from the use of maxillary orthodontic mini-implants in 31 consecutively treated patients. Radiographs were taken at the start and end of maxillary molar intrusion to evaluate the associated changes. Statistical analysis was performed using a one-sample t-test.Results:The mean treatment observation time was 1.31 years (SD  =  2.03). The maxillary first molars (P  =  0.0026) and second molars (P  =  0.039) were intruded. However, the mandibular first molars (P  =  0.0004) and second molars (P  =  0.003) erupted in adolescent patients. Both the maxillary and mandibular first molars inclined distally (P  =  0.025 and P  =  0.044, respectively). The mandibular plane angle decreased (P  =  0.036), lower facial height decreased (P  =  0.002), and the occlusal plane angle increased (P  =  0.009). The overbite increased (P < .0001). The ANB angle decreased (P < .0001). Mandibular dental and skeletal changes were more apparent in adolescents, while adults tended toward maxillary changes.Conclusions:Vertical traction from orthodontic mini-implants reduces the maxillary posterior dentoalveolar height, thereby assisting orthodontic closure of anterior open bite. However, simultaneous eruption or extrusion of the mandibular molars should be controlled. Adolescent patients tend to demonstrate more favorable effects of mandibular autorotation than do adults.     

Desire for orthodontic treatment and associated factors among adolescents in southern Brazil

Objective:To estimate the prevalence of the desire for orthodontic treatment and investigate associated factors among adolescents in southern Brazil.Materials and Methods:A cross-sectional study was carried out with 704 adolescents aged 12 and 13 years at municipal public schools in the city of Balneário Camboriú (southern Brazil). The adolescents answered a previously tested questionnaire addressing satisfaction with their dental appearance, speech function, chewing function, and the desire for orthodontic treatment. The parents/guardians answered a questionnaire addressing satisfaction with their child''s dental appearance and socioeconomic variables. A trained and calibrated orthodontist collected clinical data on malocclusion using the Dental Aesthetic Index (DAI). Statistical analysis was performed using multivariate Poisson regression with robust variance.Results:The prevalence of the desire for orthodontic treatment was 69.6% (490/704). In the adjusted analysis, the outcome was significantly more prevalent among girls (P < .001), those with difficulty chewing (P  =  .026), those dissatisfied with their dental appearance (P < .001), and those with greater malocclusion severity (P < .001). The following orthodontic characteristics were associated with the desire for orthodontic treatment in the multivariate model: diastema in anterior segment (P < .001), anterior maxillary irregularity (P < .001), maxillary overjet ≥6 mm (P < .001), and mandibular overjet (P  =  .047).Conclusions:The desire for orthodontic treatment among 12- and 13-year-old adolescents is influenced by gender, dissatisfaction with one''s dental appearance, difficulty chewing, malocclusion severity, and orthodontic characteristics. These findings should be considered together with normative indications regarding the need for orthodontic treatment in adolescents.     

Maxillary canine impaction in orthodontic patients with and without agenesis: A cross-sectional radiographic study

Objective:To assess potential associations between maxillary canine impaction (MCI) and agenesis status as well as between MCI and gender.Materials and Methods:The records of 182 orthodontic patients with agenesis (excluding the third molars) and 630 orthodontic patients without agenesis were examined. Diagnosis of MCI was based on pretreatment panoramic radiographs. Maxillary canines that had not erupted as a result of physical barrier or deflection in the eruption path at the dental age of at least 12 years were considered impacted. Logistic regression analysis was used to test for the associations of interest.Results:MCI was detected in 5.6% (n  =  35) of the nonagenesis group (28 female and 7 male participants) and in 18.1% (n  =  33) of the agenesis group (20 female and 13 male participants). Bilateral impaction was detected in 12 patients (34.3%) of the nonagenesis group and in 11 patients (33.3%) of the agenesis group. There was evidence that maxillary lateral incisor agenesis (odds ratio  =  5.1, 95% confidence interval [CI] 2.5–10.5, P < .001) and second premolar agenesis (odds ratio  =  2.6, 95% CI 1.0–6.6, P  =  .042) were significant MCI predictors after adjusting for gender. The odds of MCI were 69% higher in female versus male subjects after adjusting for agenesis status (95% CI 0.97–2.92, P  =  .063).Conclusions:This study indicates that there is evidence that agenesis status is a strong predictor of MCI, whereas gender is a weak predictor of MCI. Caution should be exercised in interpreting the results because of the observational nature of the present study.     

Influence of topical fluoride application on mechanical properties of orthodontic bonding materials under pH cycling

Objective:To evaluate in vitro the influence of topical fluoride application on the mechanical properties of orthodontic cements containing fluoride under pH cycling conditions.Materials and Methods:Edgewise brackets for maxillary central incisors were bonded to 192 bovine incisors using Transbond XT (G1), Transbond Plus Color Change (G2), and Fuji Ortho LC (G3) (n  =  64 for each group). The specimens of each group were subdivided (n  =  16) into different subgroups. Subgroup A received no topical fluoride application during pH cycling, while the experimental subgroups received topical fluoride treatments as follows: B, application three times per day of fluoride dentifrice (1450 ppm F); C, application one time per day of fluoride mouth rinse (250 ppm F); and D, combination of fluoride dentifrice and fluoride mouth rinse. After 14 days of pH cycling, the shear bond strength and Adhesive Remnant Index were evaluated statistically.Results:Polarized light microscopy showed that pH cycling induced mineral loss in all specimens. The topical application of fluoride did not have an influence on shear bond strength, although the association of fluoride dentifrice and mouth rinse increased the shear bond strength of the resinous cement without fluoride (P < .01). Regarding the Adhesive Remnant Index, no statistical differences were found within the groups G1 (P  =  .23), G2 (P  =  .47), and G3 (P  =  .74).Conclusion:Topical fluoride treatments improved the shear bond strength of resinous cement, regardless of the material''s fluoride-releasing capacity, and reached the adhesive fractures.