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.     

Malocclusion impacts adolescents' oral health–related quality of life

Objective:To test the hypothesis that malocclusion does not have an independent and negative effect on quality of life of adolescents.Materials and Methods:The cross-sectional design study comprised a sample of 519 children, aged 11 to 14 years, attending public schools in Osorio, a city in southern Brazil. One calibrated examiner carried out clinical examinations and recorded dental caries (decayed/missing/filled teeth), malocclusion (Dental Aesthetic Index), and dental trauma. Participants completed the Brazilian version of the Child Perceptions Questionnaire (CPQ_11–14), Impact Short Form, and their parents or guardians answered questions about socioeconomic status. Simple and multivariate linear regressions were performed to assess covariates for the overall CPQ_11–14 scores.Results:Greater impacts on oral health–related quality of life were observed for girls (P  =  .007), children with a lower household income (P  =  .016), those living in nonnuclear families (P < .001), and those with more decayed/missing/filled teeth (P  =  .001). Malocclusion was also associated with oral health–related quality of life: the severity of malocclusion was significantly related to higher scores of CPQ_11–14 even after scores were adjusted for control variables. CPQ_11–14 increased by approximately 1 point for each increase in the severity of malocclusion.Conclusions:Malocclusion has a negative effect on adolescents'' quality of life, independent of dental caries or traumatic dental injuries. Socioeconomic inequalities and clinical conditions are important features in adolescents'' quality of life.     

Assessing anteroposterior basal bone discrepancy with the Dental Aesthetic Index

Objective:To investigate dental appearance and cephalometric features, using a sample of orthognathic and/or orthodontic patients. A special interest was to identify the relationship of the Dental Aesthetic Index (DAI) with anteroposterior basal bone discrepancy (APBBD) and cephalometric indicators.Materials and Methods:A full sample of 159 patients in two Japanese hospitals was used. Each patient was assessed with a preorthodontic dental cast and cephalometric radiography.Results:Malocclusion with APBBD was more prevalent among high DAI subjects (P  =  .034, OR  =  1.04, 95% CI: 1.00–1.08), Class III malocclusion patients (P  =  .048, OR  =  2.32, 95% CI: 1.01–5.34) and male patients (P  =  .008, OR  =  2.96, 95% CI: 1.33–6.61). Participants scoring 88 points (the highest score in this sample) of the DAI had 16.84 times the risk of APBBD of those who scored 17 points (the lowest score in this sample). Patients with APBBD presented with a greater adjusted ANB angle (t  =  −8.10, P < .001) and a larger adjusted A-B/NF appraisal (t  =  −9.65, P < .001). The SNA angle (P < .001), the SNB angle (P  =  .002), the adjusted ANB angle (P  =  .001), and the adjusted A-B/NF appraisal (P  =  .035) were associated with DAI scores in cubic regression models.Conclusion:This study has demonstrated a relationship between the DAI and APBBD. Feasibility of using the adjusted ANB angle and the adjusted A-B/NF appraisal to assess severity of APBBD has been confirmed. The DAI may provide a supportive method to evaluate orthognathic needs. Future investigations are indicated.     

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.     

Is the adolescent's esthetic concern associated with anterior occlusal conditions or the malocclusion severity level?

ObjectivesTo assess the esthetic impact of anterior occlusal conditions and malocclusion severity levels.Materials and MethodsA population-based cross-sectional study of 700 adolescents aged 15 to 19 years was conducted. The Oral Aesthetic Subjective Impact Scale (OASIS) was used to evaluate the subjective esthetic impact of malocclusion. The Dental Aesthetic Index (DAI) criteria were used to diagnose the anterior occlusal characteristics in isolation and the severity levels of malocclusion. The variables with P < .20 in the individual analyses were tested in multiple logistic regression models, and those with P < .10 remained in the model. The adjusted odds ratio (OR) was estimated with a 95% confidence interval (CI).ResultsOf the adolescents, 42% showed negative self-perception of malocclusion. In addition, 15.4% of adolescents had severe malocclusion (DAI 3) and 18.9% very severe malocclusion (DAI 4). Crowding and spacing were shown to be 2.90 (CI: 2.06–4.09) and 2.53 (CI: 1.65–3.86) times, respectively, more likely to cause a negative esthetic impact in adolescents (P < .05). In addition, adolescents with orthodontic treatment need (DAI 2, 3, and 4) were more likely to report a negative esthetic impact (P < .05).ConclusionsAnterior crowding and spacing are the conditions that most influence the esthetic concern of adolescents. Adolescents with very severe malocclusion and higher orthodontic treatment need are more likely to report a negative esthetic impact.     

Exploring the impact of malocclusion and dentofacial anomalies on the occurrence of traumatic dental injuries in adolescents

Objective:To investigate the association between malocclusion/dentofacial anomalies and traumatic dental injuries (TDI) in adolescents.Materials and Methods:The sample of this cross-sectional study comprised 509 adolescents aged 11 to 14 years enrolled at public schools in the city of Osório, southern Brazil. Parents answered a structured questionnaire addressing demographic and socioeconomic characteristics. An examiner who had undergone a training and calibration exercise recorded malocclusion/dentofacial anomalies (Dental Aesthetic Index, DAI), TDI (Andreasen), and dental caries (World Health Organisation). Statistical analyses (SPSS software) involved Poisson regression with robust variance.Results:The prevalence of TDI was 11.6%, and the prevalence of defined, severe, and handicapping malocclusion was 24.0%, 21.6%, and 22.0%, respectively. The multivariate analysis demonstrated that the probability of TDI was approximately twofold higher among adolescents with severe malocclusion (prevalence ratio [PR] 2.22; 95% confidence interval [CI] 1.14–4.31) and handicapping malocclusion (PR 1.95; 95% CI 1.01–3.85) in comparison to those with normal occlusion or minor malocclusion. Defined malocclusion was not significantly associated with the outcome. Among the dentofacial anomalies evaluated, the probability of TDI was nearly twofold higher among adolescents with overjet greater than 3 mm (PR 1.96; 95% CI 1.14–3.37) and 2.2-fold higher among those with an abnormal molar relationship (PR 2.24; 95% CI 1.17–4.32), after controlling for confounding variables.Conclusions:Severe and handicapping malocclusion, accentuated overjet, and abnormal molar relationship were strongly associated with the occurrence of TDI. Future studies should investigate whether the treatment of these conditions can help reduce the occurrence of TDI in adolescents.     

Dental crowding: The role of genetics and tooth wear

Objective:To evaluate the role of genetics and tooth wear in the etiology of dental crowding through the analysis of a split indigenous Amazon population.Materials and Methods:Dental crowding prevalence (n  =  117), tooth wear (n  =  117), and inbreeding coefficient (n  =  288) were compared for both villages. A biometric investigation was performed by dental cast analysis of 55 individuals with no tooth loss. Mann-Whitney statistics, independent t-tests, and Fisher exact tests were used at P < .05.Results:A high coefficient of inbreeding was confirmed in the resultant village (F  =  0.25, P < .001). Tooth wear was not significantly different (P  =  .99), while a significantly higher prevalence of dental crowding was confirmed in the original village (PR  =  6.67, P  =  0.02). Forty dental arches (n  =  20) were examined in the new group, and only one (2.5%) had a dental crowding ≥5 mm. In the original villages, we found 20 arches (28.6%) with dental crowding. No difference was observed for tooth size, while larger dental arch dimensions explained a lower level of dental crowding in the resultant village.Conclusions:Our findings downplay the widespread influence of tooth wear, a direct evidence of what an individual ate in the past, on dental crowding and emphasize the role of heredity, exacerbated through inbreeding, in the etiology of this malocclusion.     

Mediation and moderation effect of the big five personality traits on the relationship between self-perceived malocclusion and psychosocial impact of dental esthetics

Objective:To explore the mediation and moderation effects of personality traits on the relationship between self-perceived malocclusion and the psychosocial impact of dental esthetics.Materials and Methods:The sample included 252 subjects (62% female) aged 12–39 years. Self-perceived malocclusion was estimated using the 10-point scale Aesthetic Component of the Index of Orthodontic Treatment Need. The Psychosocial Impact of Dental Aesthetics Questionnaire was used to assess the psychological impact and the Big Five Inventory for personality traits. Moderation and mediation effects were evaluated with Pearson correlations and stepwise regression analysis, respectively.Results:Self-perceived malocclusion ranged from 1 to 8 and was the most significant predictor of psychosocial impact of dental esthetics, whose unique contribution accounted for 11%–36.4% of variability, while age and sex accounted for 1.2%–2.5%. Personality traits had no mediating effect on this relationship. The moderating effect of agreeableness was present in the relationship between self-perceived degree of malocclusion and Social Impact (SI), Psychological Impact (PI), and Aesthetic Concern (AC) (ΔR2  =  0.035, 0.020, and 0.013, respectively; P < .001), while conscientiousness affected the relationship between perception of malocclusion and SI and PI (ΔR2  =  0.018 and 0.016, respectively; P < .05). In people with lower agreeableness and conscientiousness, increasing the severity of self-perceived malocclusion leads to less increase in SI and PI. In people with lower agreeableness, the increase influences AC in a similar manner. Extraversion, neuroticism, and openness do not have a moderating effect.Conclusions:The relationship between self-perceived malocclusion and the psychosocial impact of dental esthetics appears to be moderated and not mediated by personality traits. Adolescents and young adults with lower agreeableness and conscientiousness seem to be less affected by the increased severity of self-perceived malocclusion, as demonstrated in reporting some psychosocial impacts.     

Dental malocclusion is not related to temporomandibular joint clicking: a logistic regression analysis in a patient population

Objectives:To assess the association of several dental malocclusion features with temporomandibular joint (TMJ) click sounds in a population of temporomandibular disorder (TMD) patients.Materials and Methods:Four hundred forty-two TMD patients (72% female; 32.2 ± 5.7 years, range 25–44 years) were divided into a TMJ clicking and a no-TMJ clicking group, based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) assessment. Seven occlusal features were recorded for each patient: (1) posterior crossbite, (2) overbite, (3) open bite, (4) overjet, (5) mediotrusive and (6) laterotrusive interferences and (7) retruded contact position to maximum intercuspation (RCP-MI) slide length. A logistic regression model was created to estimate the association of occlusal features with TMJ clicking.Results:The difference between the groups as for the prevalence of the various occlusal features was generally not statistically significant, with minor exceptions. Mediotrusive interferences (P  =  .015) and RCP-MI slide ≥2 mm (P  =  .001) were the two occlusal features that were associated with the probability of having TMJ clicking, even if the adjusted odds ratios for TMJ clicking were low for both variables (1.63 and 1.89, respectively). Moreover, the amount of variance in the prevalence of TMJ clicking that was predicted by the final model was as low as 4.5% (R²  =  0.045).Conclusions:Findings from the present investigation suggested that in a population of TMD patients, the contribution of dental malocclusion features to predict TMJ click sounds is minimal with no clinical relevance.     

Cariogram caries risk profiles in adolescent orthodontic patients with and without some salivary variables

Objective:To compare the Cariogram caries risk profiles with and without salivary buffer capacity and mutans streptococci (MS) counts in adolescents with fixed orthodontic appliances.Materials and Methods:The sample consisted of 90 healthy Greek adolescents who were undergoing orthodontic treatment. The Cariogram risk model was applied through a questionnaire and clinical and salivary examinations. The actual chance of avoiding new caries was calculated, and participants were categorized into three groups (0–40%  =  high caries risk, 41–60%  =  medium caries risk, and 61–100%  =  low caries risk) using a nine-item Cariogram or by excluding either salivary buffer capacity or MS or both. Cohen''s Kappa statistical analysis was used for comparing the Cariogram outcome with and without salivary variables. The distribution of variables was compared by nonparametric marginal homogeneity tests.Results:Using the Cariogram with nine variables, 62% of the patients were assigned to the high caries risk category, 13% to the medium risk category, and 24% to the low risk category. Omission of salivary buffer capacity did not alter the risk categories significantly, while more subjects were assigned to the medium risk category when MS counts were excluded. The difference between the nine-item Cariogram and the MS-reduced version, however, was not statistically significant (P  =  .07).Conclusions:The Cariogram model may be used both with and without salivary tests for risk grouping in orthodontic practice.     

Changes in temporomandibular joint disc position and form following Herbst and fixed orthodontic treatment

Objective:To determine the changes in the position and form of the temporomandibular joint articular disc in adolescents with Class II division 1 malocclusion and mandibular retrognathism treated with the Herbst appliance (phase I) and fixed orthodontic appliance (phase II).Materials and Methods:Thirty-two consecutive adolescents went through phase I of treatment and 23 completed phase II. The temporomandibular joints were evaluated qualitatively by means of magnetic resonance images at the beginning of treatment (T1), during phase I (T2), at the end of phase I (T3), and at the end of phase II (T4).Results:Significant changes in disc position were not observed with the mouth closed between T1 × T3 (P  =  .317), T3 × T4 (P  =  .287), or T1 × T4 (P  =  .261). At T2, on average, the disc was positioned regressively. With the mouth open, no difference was observed between T1 × T3 (P  =  .223) or T1 × T4 (P  =  .082). We did observe a significant difference between T3 × T4 (P < .05). Significant changes in the disc form were found with the mouth closed between T1 × T2 (P < .001) and T2 × T3 (P < .001).Conclusions:At the end of the two-phase treatment, in general terms, the position and form of the initial articular discs were maintained; however, in some temporomandibular joints some seemingly adverse effects were observed at T4.     

Comparison of double-plate appliance/facemask combination and facemask therapy in treating Class III malocclusions

Objective:To compare the treatment effects of double-plate appliance/facemask (DPA-FM) combined therapy and facemask (FM) therapy in treating Class III malocclusions.Materials and Methods:The material consisted of lateral cephalometric radiographs of 45 children with skeletal and dental Class III malocclusion. The first treatment group comprised 15 patients (mean age  =  11 years) treated with FM. The second treatment group comprised 15 patients (mean age  = 10 years 9 months) treated with DPA-FM. The third group comprised 15 patients (mean age  =  10 years 5 months) used as controls. The paired t-test was used to evaluate the treatment effects and changes during the treatment and observation period in each group. Differences between the groups were determined by variance analysis and the Duncan test.Results:With the DPA-FM and FM appliances, the SNA and ANB angles increased significantly. These changes were statistically different compared with the control group. Lower facial height showed a greater increase in both treatment groups than in the control group. Molar relation showed a greater increase in the DPA-FM group than in the FM group. The increase in U6/ANS-PNS angle in the FM group was significantly different from the DPA-FM and control groups. The L1/NB angle and Pg-T increased significantly only in the FM group, but no significant difference was found between the treatment groups.Conclusions:In the treatment of Class III malocclusion, both appliances were effective. The significant sagittal changes in the lower incisors and pogonion in the FM group compared with the nonsignificant changes in the DPA-FM group might be due to the restriction effect of acrylic blocks in the DPA-FM group.     

Effect of socioeconomic status on normative and perceived orthodontic treatment need

Objective:To determine the influence of socioeconomic status (SES) on normative and perceived orthodontic treatment need, satisfaction with dental appearance, and regularity of dental attendance.Materials and Methods:The sample consisted of 550 adolescents (232 boys, 318 girls) aged 13 to 17 years who were categorized according to SES into three groups: low, middle, and high SES. Normative treatment need was assessed by using the Index of Orthodontic Treatment Need. Data were collected by clinical examination and face-to-face interview. The χ² test and logistic regression analysis were used for statistical analyses.Results:Approximately 34.0% of the untreated subjects had a definite dental need for treatment and 24.5% had a moderate need; among those, 53.5% were of low SES (P  =  .017). One-third of the sample had a moderate to definite esthetic need, most of whom had a low SES (P  =  .009). Of the subjects who were dissatisfied with their dental appearance and reported a self-perceived need for treatment, around one-third had a low SES. Most subjects with low SES were irregular dental attenders (P < .001). Subjects of low SES, those who had a self-perceived need for treatment, and those who were dissatisfied with their dental appearance were more likely to have a definite normative esthetic need.Conclusions:Subjects of low SES exhibited greater normative and perceived treatment needs than subjects of higher SES. They were less satisfied with their dental appearance and visited a dentist less frequently.     

Impact of wearing fixed orthodontic appliances on quality of life among adolescents: Case-control study

Objective:To investigate the impact of wearing a fixed orthodontic appliance on oral health-related quality of life (OHRQoL) among adolescents.Materials and Methods:A case-control study (1∶2) was carried out with a population-based randomized sample of 327 adolescents aged 11 to 14 years enrolled at public and private schools in the City of Brumadinho, southeast of Brazil. The case group (n  =  109) was made up of adolescents with a high negative impact on OHRQoL, and the control group (n  =  218) was made up of adolescents with a low negative impact. The outcome variable was the impact on OHRQoL measured by the Brazilian version of the Child Perceptions Questionnaire (CPQ_11–14) – Impact Short Form (ISF:16). The main independent variable was wearing fixed orthodontic appliances. Malocclusion and the type of school were identified as possible confounding variables. Bivariate and multiple conditional logistic regressions were employed in the statistical analysis.Results:A multiple conditional logistic regression model demonstrated that adolescents wearing fixed orthodontic appliances had a 4.88-fold greater chance of presenting high negative impact on OHRQoL (95% CI: 2.93–8.13; P < .001) than those who did not wear fixed orthodontic appliances. A bivariate conditional logistic regression demonstrated that malocclusion was significantly associated with OHRQoL (P  =  .017), whereas no statistically significant association was found between the type of school and OHRQoL (P  =  .108).Conclusions:Adolescents who wore fixed orthodontic appliances had a greater chance of reporting a negative impact on OHRQoL than those who did not wear such appliances.     

Agreement between adolescents and parents/caregivers in rating the impact of malocclusion on adolescents' quality of life

Objective:To assess the agreement between adolescents and their parents/caregivers regarding the impact of malocclusion on adolescents'' oral health–related quality of life (OHRQoL).Materials and Methods:A consecutive sample of 141 adolescent and parent/caregiver pairs was selected. Adolescents answered the short version of the Child Perceptions Questionnaire (CPQ_11–14), while parents answered the Parental-Caregiver Perceptions Questionnaire (P-CPQ). The CPQ_11–14 and the P-CPQ have 14 items in common that are organized through four subscales: oral symptoms (OS), functional limitations (FL), emotional well-being (EW), and social well-being (SW). Agreement on the overall score and agreement on the subscales were determined using comparison and correlation analysis. The comparison analysis was carried out by comparing the mean directional and absolute differences, and the correlation analysis was performed using the intraclass correlation coefficient (ICC).Results:A total of 135 pairs of adolescents and parents/caregivers agreed to answer the questionnaires, providing a response rate of 95.7%. The mean age of the adolescents was 11.50 years. The mean directional difference was significant for the OS (P < .001) and FL (P = .040) subscales as well as for the overall score (P = .007). Adolescents'' reports were higher than parents/caregivers'' reports. The mean absolute difference for the overall score was 7.26, representing 12.9% of the maximum possible overall score. The ICC was 0.16 for the overall score, indicating poor agreement.Conclusion:Poor agreement was observed between adolescents and their parents/caregivers in rating the impact of malocclusion on adolescents'' OHRQoL.     

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.     

Chin cup effects using two different force magnitudes in the management of Class III malocclusions

Objectives:To evaluate the dental and skeletal effects of chin cup using two different force magnitudes in the management of Class III malocclusion cases.Materials and Methods:Fifty growing patients (26 males and 24 females) with skeletal Class III and mandibular prognathism were selected. The patients were divided into three groups. Patients in group 1 (n  =  20) were treated with a chin cup and occlusal bite plane using 600 g of force per side. Patients in group 2 (n  =  20) were subjected to the same treatment as in group 1 but using 300 g of force per side. In group 3 (n  =  10) no treatment was performed. For all patients, lateral cephalograms were taken before treatment and after 1 year. Cephalograms were traced and analyzed. The collected data were analyzed statistically using one-way analysis of variance and the Tukey test.Results:In the treatment groups, the SNB angle and ramus height decreased significantly. The ANB angle, Wits appraisal, anterior facial height, mandibular plane angle, and retroclination of the mandibular incisors were significantly increased in comparison to the control group. Utilization of either force showed no significant differences, except that the reduction in the ramus height was significantly greater with the use of higher force.Conclusions:The use of a chin cup improved the maxillomandibular base relationship in growing patients with Class III malocclusion but with little skeletal effect. The utilization of either force had the same effects, except that the higher force had a more pronounced effect in reduction of ramus height.     

Three-dimensional upper-airway assessment in patients with bronchial asthma

Objective:To assess the upper airway (UAW) total volume (TV), the nasopharyngeal narrowest area (NNA), and the oropharyngeal narrowest area (ONA) in patients with bronchial asthma.Materials and Methods:The sample consisted of 52 patients divided into two groups: the control group (n  =  26; mean age  =  14.85 years), which consisted of patients not suffering from bronchial asthma; and the asthmatic group (n  =  26; mean age  =  16.65 years), which consisted of patients with bronchial asthma. To assess UAW-related variables (TV, NNA, and ONA), cone-beam computed tomography scans of the patients were evaluated by means of the Dolphin Imaging software 11.5. All measurements were repeated after 30 days, and the results were submitted to reliability tests by means of the intraclass correlation coefficient and the Bland-Altman agreement test. The values obtained for TV, NNA, and ONA for each group were compared by using Student''s t-test for independent samples (5% level of significance).Results:The results showed that the groups were matched concerning gender, cephalometric characteristics, and type of malocclusion. The asthmatic group had significantly lower TV (P  =  .01) and ONA (P  =  .007) than the control group. However, no significant difference was observed for NNA between the groups (P  =  .54).Conclusions:Bronchial asthma may be a determining factor for the reduction of UAW dimensions, as patients with asthma showed significant reductions in TV and ONA dimensions.     

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.     

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.