Paola Cozza

Interceptive treatment of palatal impaction of maxillary canines with rapid maxillary expansion: a randomized clinical trial.

INTRODUCTION Our aim in this prospective randomized clinical study was to assess the prevalence rate of eruption of palatally displaced canines, diagnosed at an early developmental stage with posteroanterior radiographs and consequently treated by rapid maxillary expansion. METHODS A sample of 60 subjects in the early mixed dentition with palatally displaced canines diagnosed on posteroanterior radiographs was enrolled in the trial. Their age range at the first observation (T1) was 7.6 to 9.6 years, with a prepubertal stage of skeletal maturity (CS1 or CS2). The 60 subjects were randomly allocated to the treatment group (TG, 35 subjects) or the no-treatment group (NTG, 25 subjects). The TG was treated with a banded rapid maxillary expander; after expansion, all patients were retained with the expander in place for 6 months. Thereafter, the expander was removed, and the patients wore a retention plate at night for a year. The NTG received no treatment. All subjects were reevaluated in the early permanent dentition (T2) (postpubertal CS4). The number of dropouts was recorded. The main outcome recorded at T2 was successful or unsuccessful eruption of the maxillary permanent canines. The starting forms at T1 for measurements on posteroanterior and panoramic films were compared in the 2 groups with the Mann-Whitney U test (P <0.05). The prevalence rates of successful and unsuccessful treatments in the TG were compared with those in NTG with chi-square tests (P <0.05). From T1 to T2, there were 3 dropouts in each group. RESULTS The final sample comprised 32 subjects in the TG and 22 subjects in the NTG. No statistically significant differences were found for any variable at T1. The prevalence rates of successful eruption of the maxillary canines were 65.7% (21 subjects) in the TG and 13.6% (3 subjects) in the NTG. The comparison was statistically significant (chi-square = 12.4; P <0.001). Subjects with palatally displaced canines in the early mixed dentition do not have transverse deficiency of the maxillary arch. CONCLUSIONS The use of a rapid maxillary expander as an early interceptive approach is effective for increasing the rate of eruption of palatally displaced canines.

Treatment and posttreatment skeletal effects of rapid maxillary expansion studied with low-dose computed tomography in growing subjects

INTRODUCTION The aim of this study was to apply low-dose computed tomography (CT) to evaluate treatment and posttreatment effects produced by rapid maxillary expansion (RME) at the levels of the midpalatal suture and the pterygoid processes. METHODS A sample of 17 subjects (7 boys, 10 girls; mean age, 11.2 years) was analyzed. Multi-slice CT scans were taken before RME, at the end of the active expansion phase, and after a retention period of 6 months. Statistical analysis was performed with ANOVA for repeated measures with post-hoc tests. RESULTS The amounts of opening of the midpalatal suture during the active phase of expansion were 3.01, 2.17, and 1.15 mm for the anterior, middle, and posterior suture widths, respectively. Pterygoid width also showed a statistically significant increase (1.49 mm). In the postretention period, all transverse measurements had significant decreases except for pterygoid width. CONCLUSIONS At the end of the retention phase after RME therapy, the transverse width of the midpalatal suture was similar to the pretreatment width, whereas the width between the pterygoid processes was significantly increased.

Immediate and post-retention effects of rapid maxillary expansion investigated by computed tomography in growing patients

OBJECTIVE To determine by low-dose computed tomography (CT) protocol the dental and periodontal effects of rapid maxillary expansion (RME). MATERIALS AND METHODS The sample comprised 17 subjects (7 males and 10 females), with a mean age at first observation of 11.2 years. Each patient underwent expansion of 7 mm. Multislice CT scans were taken before rapid palatal expansion (T0), at the end of the active expansion phase (T1), and after a retention period of 6 months (T2). On scanned images, measurements were performed at the dental and periodontal levels. Mean differences between measurements at T0, T1, and T2 were examined through analysis of variance (ANOVA) for repeated measures with post-hoc tests. RESULTS All interdental transverse measurements were significantly increased at both T1 and T2 with respect to T0. In the evaluation of T0-T1 changes, periodontal measurements were significant on the buccal aspect of banded teeth with a reduction in alveolar bone thickness corresponding to the mesial (-0.5 mm; P < .05) and distal (-0.4 mm; P < .05) roots of the right first molar and to the mesial root of the left first molar (-0.3 mm; P < .05). In the evaluation of overall T0-T2 changes, the lingual bone plate thickness of both first molars was found to be significantly increased (+0.6 mm; P < .05). CONCLUSIONS RME therapy induces a significant increase in the transverse dimension of the maxillary arch in growing subjects without causing permanent injury to the periodontal bony support of anchoring teeth discernible on CT imaging.

Phases of the dentition for the assessment of skeletal maturity: A diagnostic performance study

INTRODUCTION The aim of this study was to analyze the relationship between the circumpubertal phases of the dentition (early mixed, intermediate mixed, late mixed, early permanent) and skeletal maturity as assessed by means of the cervical vertebral maturation (CVM) method. METHODS The sample of 1000 subjects included 250 (125 boys, 125 girls) in each of the 4 dentition phases. Individual skeletal maturity was determined by using the CVM method. The relationship between the skeletal maturity (stages in CVM) and the phases of the dentition was evaluated statistically by means of indicators of diagnostic test performance. RESULTS Prepubertal stage 1 (CS1) was the variable diagnosed in the early mixed and intermediate mixed dentitions; pubertal stage 3 (CS3) was the variable diagnosed in the late mixed and early permanent dentitions. CONCLUSIONS The early mixed dentition phase showed a strong diagnostic value for the identification of prepubertal skeletal maturity (CS1), whereas the intermediate mixed dentition phase had a low diagnostic value for the same prepubertal stage. Neither the late mixed dentition nor the early permanent dentition appeared to be a valid indicator for the onset of the pubertal growth spurt.

Early orthodontic treatment of skeletal open-bite malocclusion: A systematic review

The aim of this study was a systematic review of the literature to assess the scientific evidence on the actual outcome of early treatments of open-bite malocclusions. A literature survey was done by applying the Medline database (Entrez PubMed). The survey covered the period from January 1966 to July 2004 and used the MeSH, Medical Subject Headings. The following study types that reported data on the treatment effects included: randomized clinical trials (RCT), prospective and retrospective studies with concurrent untreated as well as normal controls, and clinical trials comparing at least two treatment strategies without any untreated or normal control group involved. The search strategy resulted in 1049 articles. After selection according to the inclusionary/exclusionary criteria, seven articles qualified for the final review analysis. No RCTs of early treatment of anterior open bite have been performed. Two controlled clinical trials of early anterior open bite have been performed, and these two studies indicated the effectiveness of treatment in the mixed dentition with headgears or functional appliances (or both). Most of the studies had serious problems of lack of power because of small sample size, bias and confounding variables, lack of method error analysis, blinding in measurements, and deficient or lack of statistical methods. Thus, the quality level of the studies was not sufficient enough to draw any evidence-based conclusions.

Long-term skeletal and dental effects and treatment timing for functional appliances in Class II malocclusion

OBJECTIVE To analyze the long-term skeletal and dentoalveolar effects and to evaluate treatment timing of Class II treatment with functional appliances followed by fixed appliances. MATERIALS AND METHODS A group of 40 patients (22 females and 18 males) with Class II malocclusion consecutively treated either with a Bionator or an Activator followed by fixed appliances was compared with a control group of 20 subjects (9 females and 11 males) with untreated Class II malocclusion. Lateral cephalograms were available at the start of treatment (mean age 10 years), end of treatment with functional appliances (mean age 12 years), and long-term observation (mean age 18.6 years). The treated sample also was divided into two groups according to skeletal maturity. The early-treatment group was composed of 20 subjects (12 females and 8 males) treated before puberty, while the late-treatment group included 20 subjects (10 females and 10 males) treated at puberty. Statistical comparisons were performed with analysis of variance followed by Tukeys post hoc tests. RESULTS Significant long-term mandibular changes (Co-Gn) in the treated group (3.6 mm over the controls) were associated with improvements in the skeletal sagittal intermaxillary relationship, overjet, and molar relationship (∼3.0-3.5 mm). Treatment during the pubertal peak was able to produce significantly greater increases in total mandibular length (4.3 mm) and mandibular ramus height (3.1 mm) associated with a significant advancement of the bony chin (3.9 mm) when compared with treatment before puberty. CONCLUSION Treatment of Class II malocclusion with functional appliances appears to be more effective at puberty.

Stability of rapid maxillary expansion and facemask therapy: A long-term controlled study

INTRODUCTION The aim of this prospective controlled study was to evaluate the long-term effects of rapid maxillary expansion and facemask therapy in Class III subjects. METHODS Twenty-two subjects (9 boys, 13 girls; mean age, 9.2 years ± 1.6) with Class III disharmony were treated consecutively with rapid maxillary expansion and facemask therapy followed by fixed appliances. The patients were reevaluated at the end of the 2-phase treatment (mean age, 14.5 years ± 1.9) and then recalled about 8.5 years after the end of rapid maxillary expansion and facemask treatment (mean age, 18.7 years ± 2.1). Two groups of controls with untreated Class III malocclusion were used for statistical comparisons of the short-term and long-term intervals. Statistical comparisons were performed with the Mann-Whitney U test. RESULTS In the long term, no significant differences in maxillary changes were recorded, whereas the treatment group showed significantly smaller increases in mandibular protrusion. The sagittal maxillomandibular skeletal variables maintained significant improvements in the treatment group vs the control groups. CONCLUSIONS In the long term, rapid maxillary expansion and facemask therapy led to successful outcomes in about 73% of the Class III patients. Favorable skeletal changes were mainly due to significant improvements in the sagittal position of the mandible.

Dentoskeletal changes associated with fixed and removable appliances with a crib in open-bite patients in the mixed dentition

INTRODUCTION The aim of this study was to compare the effects of the quad-helix/crib (Q-H/C) appliance and a removable plate with a crib (RP/C) in patients with dentoskeletal open bite. METHODS Both samples consisted of 20 subjects. Lateral cephalograms were analyzed before treatment (T1) and after active treatment (T2). The average age at T1 was 8.4 years, and the mean duration of treatment was 1.5 years in both groups. The T2-T1 changes in the 2 groups were compared with a nonparametric test for independent samples (Mann-Whitney U test). RESULTS AND CONCLUSIONS Both the Q-H/C and the RP/C appliances induced favorable dental effects. However, a compliance-free appliance, such as the Q-H/C appliance, produced more favorable vertical skeletal changes.

Effect of RME and headgear treatment on the eruption of palatally displaced canines: A randomized clinical study

OBJECTIVE To determine the effectiveness of orthodontic treatment finalized on the maintenance/improvement the upper arch perimeter to assist in the successful eruption of palatally displaced maxillary canines (PDCs). MATERIALS AND METHODS The randomized prospective design comprised 64 subjects with PDCs who were randomly assigned to one of three groups: cervical pull headgear (HG); rapid maxillary expansion and cervical pull headgear (RME/HG); or untreated control group (CG). Panoramic radiographs and lateral cephalograms were evaluated at the time of initial observation (T1) and after an average period of 18 months (T2). At T2 the success of canine eruption was evaluated. A superimposition study on lateral cephalograms was undertaken to evaluate the T1-T2 changes in the sagittal position of the upper molars in the three groups. RESULTS The prevalence of successful eruption was 85.7% in the RME/HG group and 82.3% in the HG group. Both these prevalence rates were significantly greater than the success rate in untreated control subjects (36%). The cephalometric superimposition study showed a significant mesial movement of the upper first molars in the CG compared with the HG and RME/HG groups. CONCLUSIONS The use of rapid maxillary expansion and headgear (or headgear alone) in PDC cases increases the success rate of eruption of the canine significantly (almost three times more than in untreated controls).

Treatment and posttreatment effects of a facial mask combined with a bite-block appliance in Class III malocclusion

INTRODUCTION In this cephalometric investigation, we analyzed the treatment and posttreatment effects of an orthopedic protocol for Class III malocclusion consisting of a facial mask combined with a removable bite-block appliance. METHODS The treated sample consisted of 22 Class III patients treated with the facial mask and bite-block protocol before the pubertal growth spurt (mean age, 8.9 +/- 1.5 years). Treated subjects were evaluated after facial mask and bite-block therapy and at a posttreatment observation in absence of retention. The treated group was compared with a matched control group of 12 untreated Class III subjects. All treated and control subjects were postpubertal at the final observation. Significant differences between the treated and control groups were assessed with the Mann-Whitney U test (P <0.05). RESULTS Both angular and linear sagittal measurements of the maxilla showed significant improvements during active treatment. Significant improvements of SNA angle, ANB angle, overjet, and molar relationship remained stable during the posttreatment period. No significant effect was found in the mandibular skeletal measures. No significant protraction of the maxillary incisors or retraction of the mandibular incisors was observed. CONCLUSIONS A bite-block appliance in the mandibular arch with a facial mask enabled effective control of mandibular rotation with progressive closure of the gonial angle. This added to the favorable maxillary outcomes of the treatment protocol.