Morphogenetic response to activator treatment

Early Intervention in Class II Division 1 Malocclusion Using an Activator Appliance: A Case Study

The field of orthodontics has traditionally been regarded as the primary specialty within dentistry. As per Dr. Tweed's recommendation, historical treatment approaches often entailed the extraction of four premolar teeth. Nonetheless, early orthodontic intervention can frequently obviate the necessity for extractions, thus preserving the integrity, functionality, and aesthetic appeal of the dentition. This case report details a non-extraction approach for managing a developing skeletal Class II malocclusion, characterized by a skeletal disharmony between the maxilla and mandible. The chosen treatment option is influenced by factors such as the patient's age, growth potential, the severity of the malocclusion, and the patient's adherence to the prescribed treatment regimen. Myofunctional appliances have been identified as effective in addressing Class II Division 1 malocclusion resulting from mandibular retrusion.

Effects of modified twin block appliance in growing Class II high angle cases: A cephalometric study

Background

Class II malocclusions represent anteroposterior dysplasia usually resulting from mandibular retrusion. Along with a retropositioned mandible, it can be associated with either upward or backward jaw rotation. High angle cases are often associated with a short ramal height, steeper mandibular plane, and large gonial angle. Twin block is a commonly used myofunctional appliance that incorporates bite planes that direct the occlusal forces in a more favorable direction for correction of the retrognathic mandible. We aimed to evaluate skeletal, dental, and soft tissue changes following modified twin block appliance therapy in high-angle cases.

Methods

A cephalometric study was performed on 15 growing (10-14 years) high angle (Frankfort mandibular angle 28-35°) Class II Division I malocclusion patients undergoing twin block therapy. Skeletal, dental, and soft tissue changes were evaluated by cephalometric analysis using Dolphin software.

Results

Pre- and post-treatment changes in cephalograms were assessed by analysis of variance and paired t-test. Significant changes in the position of the mandible (angle between Sella-Nasion-Point B [SNB] increased by 3.9 degrees, P=0.02), Wits appraisal (decreased by 1.54 mm, P=0.04), maxillo-mandibular relationship (angle between Point A-Nasion-Point B [ANB] decreased by 3.74 degrees, P=0.02) were observed. Soft tissue changes like the nasolabial angle were also significant, increasing by 3.8 degrees (P=0.04) and lower lip relation to E-line (reduction in lower lip protrusion) by 2 mm (P=0.04). Vertical parameters showed non-significant changes, like the Frankfort mandibular angle (FMA) increased by 0.07 degrees, (P=0.67), the angle between Sella-Nasion and Gonion-Gnathion (SN-Go-Gn) increased by 0.33 degrees, (P=0.67), Y-axis increased by 0.2 degrees, (P=0.32). The upper incisor inclination decreased non-significantly from 115.27±1.33 to 113.42±1.65 degrees, (P=0.12) and lower incisor increased non-significantly from 100.13±2.23 to 101.80 ±1.37 degrees, (P=0.08).

Conclusions

Modified twin block appliance can be used to successfully treat Class II Division I high angle cases with good vertical control.

Twin-block and mandibular anterior repositioning appliances effects in Class II malocclusion correction

INTRODUCTION

The objective of this study was to compare the cephalometric changes in Class II Division 1 malocclusion patients treated with the Twin-block (TB) and the mandibular anterior repositioning appliance (MARA).

METHODS

This retrospective study was performed with 132 lateral cephalograms of patients with Class II malocclusion divided into 3 groups: a TB group comprised 21 patients with mean initial and final ages of 10.59 and 11.97 years, respectively, treated for a mean period of 1.38 years; a MARA group comprised 21 patients with mean initial and final ages of 11.98 and 13.20 years, respectively, treated for a mean period of 1.22 years; and a control group included 24 subjects with untreated Class II malocclusion with mean initial and final ages of 10.55 and 12.01 years, respectively, observed for a mean period of 1.46 years. Cephalometric intergroup comparisons regarding the treatment changes (T2 - T1) were performed with the analysis of covariance, followed by Tukey tests.

RESULTS

Both appliances demonstrated significant restriction of the maxilla and improvement of the maxillomandibular relationship. The MARA produced a significantly greater amount of labial tipping and protrusion of the mandibular incisors than the other groups. The TB showed significant extrusion of the mandibular incisors and molars compared with MARA and control, respectively. Both treated groups reduced the overjet and overbite. The MARA presented a significantly greater reduction in the molar relationship than the other groups.

CONCLUSIONS

The appliances showed a headgear effect on the maxilla and effectively changed Class II cephalometric parameters through a combination of skeletal and dentoalveolar effects. TB showed a greater increase in LAFH. MARA promoted greater labial tipping and protrusion of the mandibular incisors.

IGF-1 TMJ injections enhance mandibular growth and bone quality in juvenile rats

OBJECTIVES

Dentofacial orthopaedic treatment of mandibular hypoplasia has unpredictable skeletal outcomes. Although several biomodulators including insulin-like growth factor 1 (IGF-1) are known to contribute to chondrocyte proliferation, their efficacy in modulating mandibular growth has not been validated. The aim of this study was to determine the effect of locally delivered IGF-1 on mandibular growth and condylar bone quality/quantity in juvenile rats.

SETTING AND SAMPLE POPULATION

Institutional vivarium using twenty-four 35-day-old male Sprague-Dawley rats.

METHODS

PBS or 40 µg/kg (low-dose) IGF-1 or 80 µg/kg (high-dose) IGF-1 was injected bilaterally into the temporomandibular joints of the rats at weekly intervals for four weeks. Cephalometric and micro-computed tomography measurements were used to determine mandibular dimensions. Bone and tissue mineral density, volume fraction and mineral content were determined, and serum IGF-1 concentrations assayed.

RESULTS

Intra-articular administration of high-dose IGF-1 contributed to a significant 6%-12% increase in mandibular body and condylar length compared to control and low-dose IGF-1-treated animals. Additionally, IGF-1 treatment resulted in a significant decrease in the angulation of the lower incisors to mandibular plane. Condylar bone volume, bone volume fraction, mineral content and mineral density were significantly increased with high-dose IGF-1 relative to control and low-dose IGF-1 groups. Serum IGF-1 levels were similar between all groups confirming limited systemic exposure to the locally administered IGF-1.

CONCLUSION

Local administration of high-dose 80 µg/kg IGF-1 enhances mandibular growth and condylar bone quality and quantity in growing rats. The findings have implications for modulating mandibular growth and potentially enhancing condylar bone health and integrity.

Evaluating the effects of functional orthodontic treatment on mandibular osseous structure using fractal dimension analysis of dental panoramic radiographs

OBJECTIVE

To evaluate the effects of functional appliance treatment on mandibular trabecular structure using fractal dimension (FD) analysis of dental panoramic radiographs.

MATERIALS AND METHODS

This study was conducted using digital panoramic radiographs of 45 patients with Class II malocclusion treated with functional appliances (treatment group, mean age: 11.39 ± 0.97 years; 23 girls, 22 boys) acquired before (T0) and after (T1) treatment and the panoramic radiographs of 45 control subjects who had undergone no orthodontic treatment (control group, mean age: 11.31 ± 0.87 years; 23 girls, 22 boys). FD values in the condylar process, mandibular corpus, and mandibular angle were analyzed from the panoramic radiographs of both groups.

RESULTS

Analysis of changes in FD between T0 and T1 revealed significant increases in the FD values of the right and left condylar processes and right mandibular corpus in the treatment group (P < .001) and in the right condylar process in the control group (P < .05). Between-group comparisons demonstrated that the treatment group showed greater changes in the condylar process (right, P < .001; left, P < .05) and right mandibular corpus (P < .05) compared to controls. Correlation analysis between the cephalometric and FD changes in the treatment group showed the right condylar process changes were negatively correlated with GoGn/SN angle (P < .05) and positively correlated with Co-Go (P < .05), although these correlations were weak.

CONCLUSIONS

FD analysis demonstrated significant changes in trabeculation of the condyle and mandibular corpus in the treatment group compared to the control group. Functional appliance treatment may lead to skeletal correction by altering skeletal form and trabeculation of the mandibular bone.

Treatment efficiency of activator and skeletal anchored Forsus Fatigue Resistant Device appliances

OBJECTIVES

The aim of the study was to investigate the treatment efficiency of miniplate anchored Forsus Fatigue Resistant Device (MAF) as compared with the activator appliance.

MATERIALS AND METHODS

Mandibular retrognathia was treated with two methods, the MAF group (8 girls, 11 boys, mean age 13.03 ± 0.69 years) and the activator group (7 girls, 12 boys, mean age 12.68 ± 0.73 years). An untreated control group (9 girls, 10 boys, mean age 12.95 ± 0.73 years) was constructed to eliminate growth-related changes through the American Association of Orthodontists Foundation Legacy Collection. Data of 114 lateral cephalograms were analyzed.

RESULTS

The inhibition of the maxillary growth was greater in the MAF group, whereas forward displacement of the mandible was higher in the activator group (P < 0.05). Sagittal maxillomandibular relation was improved similarly in both treatment groups (P < 0.05). Mandibular length was increased in both treatment groups with the highest increase in the activator group (P < 0.05). Retroclination of the incisors was observed in the MAF group (P < 0.05). The upper lip was retruded in the MAF group and lower lip was protruded in the activator group (P < 0.05).

CONCLUSION

The activator created greater mandibular changes, whereas the MAF provides somewhat smaller mandibular changes due to the restriction caused by retroclined maxillary incisors.

CLINICAL RELEVANCE

Although both MAF and activator treatments caused favorable maxillomandibular changes, new treatment alternatives that reduce dentoalveolar side effects and eliminate patient cooperation are still required to achieve skeletal correction in class II malocclusion treatment in growing patients.

A Prospective Study Comparing Adolescent and Post-Adolescent Periods Regarding Effects of Activator Appliance in Patients with Class II Mandibular Retrognathia by Using 3dMDface Analysis and Cephalometry

BACKGROUND The purpose of this prospective study was to compare adolescent and post-adolescent growth periods regarding the effectiveness of conventional activator appliance in patients with Class II mandibular retrognathia by using lateral cephalometric radiographs and three-dimensional photogrammetry (3dMDface). MATERIAL AND METHODS We enrolled 2 groups: 15 patients in the adolescent growth period and 17 patients in the post-adolescent growth period. All patients had Class II anomaly with mandibular retrognathia and were treated with conventional activator appliances. Lateral cephalometric radiographs and three-dimensional photogrammetric views were obtained at the beginning and end of the activator treatment of Class II patients. Maxillomandibular discrepancy, mandibular protrusion and lengths, convexity angles, facial heights, and dental measurements were evaluated cephalometrically. Projections of the lips and the chin and volumetric measurements of the lip and the mandibular area were assessed using three-dimensional photogrammetry. RESULTS Conventional activator therapy resulted in similar effects in both growth periods regarding improvements in the mandibular sagittal growth and maxillomandibular relationship (ANB° and the SNB° angles). Mandibular effective length was increased (Co-Gn length) and the maxillary horizontal growth was restricted (decreased SNA° angle) in both groups following the treatment. Treatment duration was significantly longer in the post-adolescent group. Increases in the projections of menton, pogonion, and sublabial points were observed in the three-dimensional photogrammetric views. Total lip volume was reduced while the mandibular volume was significantly increased in both groups. Lower gonial angle showed a greater increase in the post-adolescent group. CONCLUSIONS Correction of Class II anomaly with mandibular retrognathia was achieved with a combination of dental and skeletal changes in both growth periods. Conventional activator therapy may be an alternative treatment approach in the late growth period as it led to significant skeletal and dental changes.

Which factors influence orthodontists in their decision to extract? A questionnaire survey

Background

To evaluate the relative influence of different criteria in the choice between extraction and nonextraction treatment in current orthodontics, and to assess how the percentage of extractions has evolved over time.

Material and Methods

Pre-treatment records (panoramic radiograph, lateral cephalogram, study casts and photographs) of fourteen cases in permanent dentition (adult or adolescent) with class I molar relationship and moderate anterior crowding were evaluated by 28 orthodontists. For each case, each orthodontist filled out a questionnaire reporting his treatment plan proposal (extraction or nonextraction) and the importance of specific parameters in his decision-making process, using categorical scales. Orthodontists practicing for more than 15 years were also asked to compare this decision with the one they would have taken at the beginning of their professional career.

Results

The two most important factors in the decision-making were the soft tissue profile and the amount of crowding. The least important factor was the presence of third molars. In cases of nonextraction treatment, the lack of space was managed mostly by dental expansion and stripping. Twenty percent of the case evaluations revealed extraction(s) decisions. Among the orthodontists practicing for more than 15 years, the current extraction rate reached 24%, whereas the same orthodontists reported they would have extracted in 39% of the cases in the past.

Conclusions

The present study suggests that soft tissue profile has a higher impact than traditional criteria such as cephalometric measurements in the extraction decision. This is associated with a decreased extractions rate compared to the past.

Key words:Orthodontics, extractions, survey, treatment planning.

Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children and adolescents

BACKGROUND

Prominent upper front teeth are a common problem affecting about a quarter of 12-year-old children in the UK. The condition develops when permanent teeth erupt. These teeth are more likely to be injured and their appearance can cause significant distress. Children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of their teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait and provide treatment in adolescence.

OBJECTIVES

To assess the effects of orthodontic treatment for prominent upper front teeth initiated when children are seven to 11 years old ('early treatment' in two phases) compared to in adolescence at around 12 to 16 years old ('late treatment' in one phase); to assess the effects of late treatment compared to no treatment; and to assess the effects of different types of orthodontic braces.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 27 September 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 8), MEDLINE Ovid (1946 to 27 September 2017), and Embase Ovid (1980 to 27 September 2017). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomised controlled trials of orthodontic treatments to correct prominent upper front teeth (Class II malocclusion) in children and adolescents. We included trials that compared early treatment in children (two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces versus late treatment in adolescents (one-phase) with any type of orthodontic braces or head-braces, and trials that compared any type of orthodontic braces or head-braces versus no treatment or another type of orthodontic brace or appliance (where treatment started at a similar age in the intervention groups).We excluded trials involving participants with a cleft lip or palate, or other craniofacial deformity/syndrome, and trials that recruited patients who had previously received surgical treatment for their Class II malocclusion.

DATA COLLECTION AND ANALYSIS

Review authors screened the search results, extracted data and assessed risk of bias independently. We used odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous outcomes, and mean differences (MDs) and 95% CIs for continuous outcomes. We used the fixed-effect model for meta-analyses including two or three studies and the random-effects model for more than three studies.

MAIN RESULTS

We included 27 RCTs based on data from 1251 participants.Three trials compared early treatment with a functional appliance versus late treatment for overjet, ANB and incisal trauma. After phase one of early treatment (i.e. before the other group had received any intervention), there was a reduction in overjet and ANB reduction favouring treatment with a functional appliance; however, when both groups had completed treatment, there was no difference between groups in final overjet (MD 0.21, 95% CI -0.10 to 0.51, P = 0.18; 343 participants) (low-quality evidence) or ANB (MD -0.02, 95% CI -0.47 to 0.43; 347 participants) (moderate-quality evidence). Early treatment with functional appliances reduced the incidence of incisal trauma compared to late treatment (OR 0.56, 95% CI 0.33 to 0.95; 332 participants) (moderate-quality evidence). The difference in the incidence of incisal trauma was clinically important with 30% (51/171) of participants reporting new trauma in the late treatment group compared to only 19% (31/161) of participants who had received early treatment.Two trials compared early treatment using headgear versus late treatment. After phase one of early treatment, headgear had reduced overjet and ANB; however, when both groups had completed treatment, there was no evidence of a difference between groups in overjet (MD -0.22, 95% CI -0.56 to 0.12; 238 participants) (low-quality evidence) or ANB (MD -0.27, 95% CI -0.80 to 0.26; 231 participants) (low-quality evidence). Early (two-phase) treatment with headgear reduced the incidence of incisal trauma (OR 0.45, 95% CI 0.25 to 0.80; 237 participants) (low-quality evidence), with almost half the incidence of new incisal trauma (24/117) compared to the late treatment group (44/120).Seven trials compared late treatment with functional appliances versus no treatment. There was a reduction in final overjet with both fixed functional appliances (MD -5.46 mm, 95% CI -6.63 to -4.28; 2 trials, 61 participants) and removable functional appliances (MD -4.62, 95% CI -5.33 to -3.92; 3 trials, 122 participants) (low-quality evidence). There was no evidence of a difference in final ANB between fixed functional appliances and no treatment (MD -0.53°, 95% CI -1.27 to -0.22; 3 trials, 89 participants) (low-quality evidence), but removable functional appliances seemed to reduce ANB compared to no treatment (MD -2.37°, 95% CI -3.01 to -1.74; 2 trials, 99 participants) (low-quality evidence).Six trials compared orthodontic treatment for adolescents with Twin Block versus other appliances and found no difference in overjet (0.08 mm, 95% CI -0.60 to 0.76; 4 trials, 259 participants) (low-quality evidence). The reduction in ANB favoured treatment with a Twin Block (-0.56°, 95% CI -0.96 to -0.16; 6 trials, 320 participants) (low-quality evidence).Three trials compared orthodontic treatment for adolescents with removable functional appliances versus fixed functional appliances and found a reduction in overjet in favour of fixed appliances (0.74, 95% CI 0.15 to 1.33; two trials, 154 participants) (low-quality evidence), and a reduction in ANB in favour of removable appliances (-1.04°, 95% CI -1.60 to -0.49; 3 trials, 185 participants) (low-quality evidence).

AUTHORS' CONCLUSIONS

Evidence of low to moderate quality suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective for reducing the incidence of incisal trauma than providing one course of orthodontic treatment in adolescence. There appear to be no other advantages of providing early treatment when compared to late treatment. Low-quality evidence suggests that, compared to no treatment, late treatment in adolescence with functional appliances, is effective for reducing the prominence of upper front teeth.

Cephalometric appraisal of Class II treatment effects after functional and fixed appliances: a retrospective study

Objective

To assess the dental, skeletal, and profile changes after functional appliances and subsequent fixed appliances treatment in order to quantify their effect and evaluate the influence of initial incisal inclination and growth pattern.

Materials and methods

A retrospective cephalometric analysis was performed in 125 patients (77 females and 48 males). Three lateral cephalograms per patient were available: before treatment (T0, mean age 11.9 years), after functional treatment (T1, mean age 12.9 years), and after fixed appliances (T2, mean age 14.8 years).

Results

At T1, a decrease of SNA (0.38° ± 0.77, P < 0.05), an increase of SNB (1.46° ± 0.66, P < 0.05), and a less convex profile (increase N'-Sn'-Pog' of 2.93° ± 0.87, P < 0.05) were observed as compared to T0. The position of the upper incisors normalizes: initially retroclined upper incisors showed proclination and proclined incisors retroclination. At T1, proclination of the lower incisors was also noticed, being smaller the higher the initial I^NB. At T2, no significant changes in upper and lower incisor position were noticed compared to T1, as well as a decrease of the SNA (1.17° ± 0.75, P < 0.001) and SNB angles (0.41° ± 0.64, P < 0.05) and a stable profile convexity.

Conclusion

The improvement of the Class II relationship at T1 was mostly due to dentoalveolar changes: correction of the upper incisor position and proclination of the lower incisors. Skeletal changes were also noticed: constriction of maxillary growth combined with a growth stimulation of the mandible. At T2, no further proclination of the lower incisors was noticed.

Long-term treatment effects of the FR-2 appliance: a prospective evalution 7 years post-treatment

AIM

To examine the long-term effects induced by treatment with the function regulator (FR-2) appliance 7 years post-treatment compared with untreated class II subjects.

SUBJECTS AND METHODS

The FR-2 sample was collected prospectively and comprised 17 subjects (10 boys and 7 girls, mean age 10.8 years) who were treated with the FR-2 appliance for 1.7 years and re-evaluated 7.1 years after treatment. The step-by-step mandibular advancement was performed gradually (increments up to 3-4 mm), until a 'super class I' molar relationship was obtained. The control group consisted of 17 class II subjects (9 boys and 8 girls, mean age 11.3 years) with class II malocclusion, excessive overjet, and class II molar relationship, matched to the treated group as to ages at all times, gender distribution, and stages of skeletal maturity (evaluated by the cervical vertebral maturation method). The lateral cephalograms were analysed at T1 (initial), T2 (final), and T3 (7.1 years post-treatment). The compatibility between the groups and the comparisons of their changes at T1-T2, T2-T3, and T1-T3 intervals were examined by independent sample t-tests (P < 0.05).

RESULTS

FR-2 treatment provided a significant improvement in the maxillomandibular relationship due to an increase in mandibular length compared with controls, which remained stable over time. Also overjet, overbite, and molar relationship corrections demonstrated stability. Among dentoalveolar changes, only the increased mesial movement of the mandibular molars in the FR-2 group demonstrated stability.

CONCLUSIONS

Correction of class II malocclusion remained stable 7 years after FR-2 treatment mainly due to the stability of the skeletal changes.

Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children

BACKGROUND

Prominent upper front teeth are a common problem affecting about a quarter of 12-year old children in the UK. The correction of this condition is one of the most common treatments performed by orthodontists. This condition develops when the child's permanent teeth erupt and children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of the teeth. These teeth are more likely to be injured and their appearance can cause significant distress.If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait until the child is older and provide treatment in early adolescence.

OBJECTIVES

To assess the effects of orthodontic treatment for prominent upper front teeth when this treatment is initiated when the child is seven to 11 years old compared to when they are in early adolescence, or when treatment uses different types of orthodontic braces.

SEARCH METHODS

We searched the following databases: Cochrane Oral Health Group's Trials Register (to 17 April 2013), CENTRAL (The Cochrane Library 2013, Issue 3), MEDLINE (OVID) (1946 to 17 April 2013) and EMBASE (OVID) (1980 to 17 April 2013). There were no restrictions regarding language or publication date.

SELECTION CRITERIA

Randomised controlled trials of children and/or adolescents (age < 16 years) on early treatment (either one or two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces compared with late treatment with any type of orthodontic braces or head-braces; or, on any type of orthodontic braces or head-braces compared with no treatment or another type of orthodontic brace or appliance (with treatment starting in children of similar ages in both groups) to correct prominent upper front teeth.

DATA COLLECTION AND ANALYSIS

Review authors screened the search results, extracted data and assessed risk of bias independently, used odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous outcomes, mean differences (MDs) and 95% CIs for continuous outcomes and a fixed-effect model for meta-analyses as there were fewer than four studies.

MAIN RESULTS

We included 17 studies based on data from 721 participants.Three trials (n = 343) compared early (two-phase) treatment (7-11 years of age) with a functional appliance, with adolescent (one-phase) treatment. Statistically significant differences in overjet, ANB and PAR scores were found in favour of functional appliance when the first phase of early treatment was compared with observation in the children due to receive treatment in adolescence. However, at the end of treatment in both groups, there was no evidence of a difference in the overjet (MD 0.21, 95% CI -0.10 to 0.51, P = 0.18) (low quality evidence), final ANB (MD -0.02, 95% CI -0.47 to 0.43, P = 0.92), PAR score (MD 0.62, 95% CI -0.66 to 1.91, P = 0.34) or self concept score (MD 0.83, CI -2.31 to 3.97, P = 0.60). However, two-phase treatment with functional appliance showed a statistically significant reduction in the incidence of incisal trauma (OR 0.59, 95% CI 0.35 to 0.99, P = 0.04) (moderate quality evidence). The incidence of incisal trauma was clinically significant with 29% (54/185) of patients reporting new trauma incidence in the adolescent (one-phase) treatment group compared to only 20% (34/172) of patients receiving early (two-phase) treatment.Two trials (n = 285), compared early (two-phase) treatment using headgear, with adolescent (one-phase) treatment. Statistically significant differences in overjet and ANB were found in favour of headgear when the first phase of early treatment was compared with observation in the children due to receive treatment in adolescence. However, at the end of treatment in both groups, there was no evidence of a difference in the overjet (MD 0.22, 95% CI -0.56 to 0.12, P = 0.20) (low quality evidence), final ANB (MD -0.27, 95% CI -0.80 to 0.26, P = 0.32) or PAR score (MD -1.55, 95% CI -3.70 to 0.60, P = 0.16). The incidence of incisal trauma was, however, statistically significantly reduced in the two-phase treatment group (OR 0.47, 95% CI 0.27 to 0.83, P = 0.009) (low quality evidence). The adolescent treatment group showed twice the incidence of incisal trauma (47/120) compared to the young children group (27/117).Two trials (n = 282) compared different types of appliances (headgear and functional appliance) for early (two-phase) treatment. At the end of the first phase of treatment statistically significant differences, in favour of functional appliances, were shown with respect to final overjet only. At the end of phase two, there was no evidence of a difference between appliances with regard to overjet (MD -0.21, 95% CI -0.57 to 0.15, P = 0.26), final ANB (MD -0.17, 95% CI -0.67 to 0.34, P= 0.52), PAR score (MD -0.81, 95% CI -2.21 to 0.58, P = 0.25) or the incidence of incisal trauma (OR 0.79, 95% CI 0.43 to 1.44, P = 0.44).Late orthodontic treatment for adolescents with functional appliances showed a statistically significant reduction in overjet of -5.22 mm (95% CI -6.51 to -3.93, P < 0.00001) and ANB of -2.37° (95% CI -3.01 to -1.74, P < 0.00001) when compared to no treatment (very low quality evidence).There was no evidence of a difference in overjet when Twin Block was compared to other appliances (MD 0.01, 95% CI -0.45 to 0.48, P = 0.95). However, a statistically significant reduction in ANB (-0.63°, 95% CI -1.17 to -0.08, P = 0.02) was shown in favour of Twin Block. There was no evidence of a difference in any reported outcome when Twin Block was compared with modifications of Twin Block.There was insufficient evidence to determine the effects of Activator, FORSUS FRD EZ appliances, R-appliance or AIBP.

AUTHORS' CONCLUSIONS

The evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective in reducing the incidence of incisal trauma than providing one course of orthodontic treatment when the child is in early adolescence. There appears to be no other advantages for providing treatment early when compared to treatment in adolescence.

Effectiveness of bionator therapy for Class II malocclusions: a comparative long-term study

OBJECTIVE

The goal of this retrospective study was to examine the effectiveness of isolated bionator therapy in Class II patients both longitudinally and over the long term. We aimed to determine whether skeletal and/or dentoalveolar reactions differ in relationship to the Angle Class (II, Division 1 vs. II, Division 2).

PATIENTS AND METHODS

A total of 50 juvenile patients with Class II malocclusion (♀ n = 26, ♂ n = 24) were included. A total of 24 patients presented an Angle Class II, Division 1 and 26 an Angle Class II, Division 2. We compared the patients' lateral cephalograms taken at the beginning of treatment (t1: 10.1 years), after active therapy (t2: 13.8 years), and at the end of retention (t3: 16.4 years) analyzing the following cephalometric parameters: SNA, SNB, ANB, ANB(ind), SNPog, Wits appraisal, U1-SN, U1-SpP, L1-MeGo, interincisal angle. Mean and standard deviations of each of the variables were calculated. Differences between t1-t2 and t2-t3 were tested for statistical significance. Changes in the variables were then analyzed biometrically for specific differences in terms of Angle Class (II, Division 1 vs. II, Division 2).

RESULTS

Between t1 and t2, SNB (p = 0.000) and SNPog (p = 0.000) increased significantly, as did ANB (p = 0.000), while the difference between ANB and ANB(ind) (p = 0.000) and Wits appraisal (p = 0.000) decreased significantly. The dentoalveolar variables U1-SN, U1-SpP, and the interincisal angle changed significantly in both groups. The inclination of the upper incisors was corrected by retrusion in the Class II, Division 1 and by protrusion in the Class II, Division 2 group. Only marginal changes in all variables between t2 and t3 were observed.

CONCLUSION

A significant skeletal effect (even in long-time stability) through bionator treatment could be confirmed in this study of Class II, Divisions 1 and 2 patients. The desired effect on the upper front teeth was realized, and there was no appreciable dentoalveolar compensation in the mandible.

Dentaoalveolar changes in young adult patients with Class II/1 malocclusion treated with the Herbst appliance and an activator

Background/Aim. Functional appliances can be used effectively in the treatment of skeletal Class II/1 malocclusions. The best treatment results are obtained during active period of facial growth when skeletal, as well as dentoalveolar, changes occur. In comparison with removable functional appliances, such as activator, that are effective only during adolescent period of growth, the Herbst fixed appliance is also successful at the end of the growth period. It also offers a shorter treatment time and a patient compliance is not necessary. The aim of this study was to analyze and compare dentoalveolar changes in the group of young adult patients with Class II/1 malocclusion treated with the Herbst appliance and an activator. Methods. The sample for this study consisted of 50 patients of both sexes, 14-21 years of age with Class II/1 malocclusion. For estimating the effect of functional appliances used, the following cephalometrics parameters were determined: inclination of the upper and lower incisors, interincisal angle, antero-posterior molars relationships, overjet and overbite. The results obtained were statistically tested. Results. The cephalometric findings after the treatment indicated retroinclination of upper incisors (average value of 9?) and proclination of lower incisors (average value of 7?), mostly expressed in the patients treated by Herbst appliance (p < 0.001). Increased overjet and distocclusion were completely corrected in the group of patients treated with the Herbst appliance, while the correction of malocclusion in the activator group was only partially accomplished. No changes in the overbite were noticed at the end of the treatment in both groups. Conclusion. The results of this study revealed that the Herbst appliance is more effective in the treatment of Class II/1 malocclusion in young adults in comparison with the activator.

Class II Division 1 malocclusion with a high mandibular plane angle corrected with 2-phase treatment

A 10-year-old girl with maxillary protrusion and crowding of the maxillary and mandibular anterior teeth was treated in 2 phases. In the first phase of treatment, maxillary anterior growth was restrained and mandibular anterior growth promoted for skeletal improvement. In the second phase, at age 13, 4 first premolars were extracted, and an edgewise appliance was used for alveolar improvement. Because the patient had a high mandibular plane angle with a large Frankfort-mandibular plane angle, special care was taken from the beginning to prevent mandibular clockwise rotation. The Frankfort-mandibular plane angle decreased 3.1 degrees at posttreatment. In addition to the skeletal changes, we obtained a favorable lateral profile. This was achieved by the alveolar changes from the lingual movement of the maxillary and mandibular anterior teeth, and the anterior growth of the nasal apex region. The occlusion was stable at the 38-month postretention follow-up.

Clinical effects of fixed functional Herbst appliance in the treatment of class II/1 malocclusion

Introduction. Sagittal mandible deficiency is the most common cause of skeletal Class II malocclusion. Treatment objective is to stimulate sagittal mandible growth. Fixed functional Herbst appliance use is beneficial for shortening the time required for treatment and does not depend on patient compliance. Case outline. A 13-year-old girl was referred to the Clinic of Orthodontics, School of Dentistry in Belgrade following previous unsuccessful treatment of her skeletal Class II malocclusion using an activator. The patient's poor cooperation had led to failure of the treatment. Patient was subjected to the Herbst treatment for 6 months followed by fixed appliance for another 8 months. Lateral cephalograms before and after the treatment was performed. The remodelation of condylar and fossal articulation was assessed by superimposition of pre- and post-treatment temporomandibular joint tomograms. The promotion of oral hygiene and fluoride use was performed because orthodontic treatment carries a high caries risk and risk for periodontal disease. Skeletal and dental changes were observed after treatment (correction [Max+Mand]: molar relation 7 mm, overjet 8 mm, skeletal relation 5 mm, molars 2 mm, incisors 3 mm). Combination of Herbst and fixed appliances was effective in the treatment of dental and skeletal irregularities for a short period of time. Conclusion . In the retention period, 14 months after treatment, occlusal stability exists. Follow-up care in oral prevention is based on regular recalls at the dental office and supervision at home by the parents.

Short-term anteroposterior treatment effects of functional appliances and extraoral traction on class II malocclusion. A meta-analysis

OBJECTIVE

To evaluate the anteroposterior short-term skeletal and dental effects on Class II malocclusion in growing patients following treatment with functional appliances (activators or twin block), extraoral traction, or combination appliances (appliances with both functional and extraoral traction components), based on published data.

MATERIALS AND METHODS

A literature search was carried out identifying a total of nine prospective clinical trials. The data provided in the publications underwent meta-analysis using the random effects model with regard to SNA, SNB, ANB, and overjet.

RESULTS

All appliance groups showed an improvement in sagittal intermaxillary relationships (decrease in ANB) when compared to untreated subjects. Activators and twin block appliances accomplish this mainly by acting on the mandible (increases in SNB) while twin block appliances also seem to act on the maxilla (decrease in SNA). Extraoral traction appliances achieve this by acting on the maxilla (decreases in SNA). Combination appliances mainly act on the mandible (increase in SNB). Activators, twin block, and combination appliances also reveal a decrease in overjet, which is not the case in the singular use of extraoral traction.

CONCLUSIONS

Intermaxillary changes being present in all appliance groups, anteroposterior treatment response following the use of functional appliances and/or extraoral traction in growing class II malocclusion patients is most evident in one of the two jaws (mandible for activators and combination appliances and maxilla for extraoral traction) except for the twin block group, which shows changes on both jaws.

Treatment effects of headgear biteplane and bionator appliances

INTRODUCTION

The purpose of this investigation was to evaluate the dentoalveolar and skeletal cephalometric changes produced by headgear (HG) biteplane and bionator appliances in subjects with Class II Division 1 malocclusion.

METHODS

The sample comprised 60 patients with Class II Division 1 malocclusion; 30 (15 boys, 15 girls; mean age, 10.02 years) were treated with the HG biteplane for a mean period of 1.78 years, and 30 (15 boys, 15 girls; mean age, 10.35 years) were treated with a bionator for a mean period of 1.52 years. For comparison, a control group of 30 untreated Class II children (15 boys, 15 girls) with an initial mean age of 10.02 years, followed for 1.48 years, was established. Lateral cephalometric headfilms were obtained at the beginning and at the end of the treatment or observation period.

RESULTS

The results showed that forward growth of the maxilla was restricted in the HG biteplane group. Bionator treatment, however, produced a statistically significant increase in mandibular protrusion. Both appliances provided increases in total mandibular and ramus lengths. There were no statistically significant differences in craniofacial growth direction. The mandibular incisors were tipped labially with bionator treatment and lingually in the HG biteplane group. The maxillary incisors were retruded with both appliances; there also were a significant increase in mandibular posterior dentoalveolar height and a restriction in the vertical development of the maxillary molars.

CONCLUSIONS

Class II treatment with HG biteplane and bionator appliances is efficient over the short term, with pronounced dentoalveolar movements and smaller but still significant skeletal effects. The stability of these results should be examined in a long-term study.

Orthodontic treatment for prominent upper front teeth in children

BACKGROUND

Prominent upper front teeth are an important and potentially harmful type of orthodontic problem. This condition develops when the child's permanent teeth erupt and children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of the teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait until the child is older and provide treatment in early adolescence. When treatment is provided during adolescence the orthodontist may provide treatment with various orthodontic braces, but there is currently little evidence of the relative effectiveness of the different braces that can be used.

OBJECTIVES

To assess the effectiveness of orthodontic treatment for prominent upper front teeth, when this treatment is provided when the child is 7 to 9 years old or when they are in early adolescence or with different dental braces or both.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched. The handsearching of the key international orthodontic journals was updated to December 2006. There were no restrictions in respect to language or status of publication. Date of most recent searches: February 2007.

SELECTION CRITERIA

Trials were selected if they met the following criteria: design - randomised and controlled clinical trials; participants - children or adolescents (age < 16 years) or both receiving orthodontic treatment to correct prominent upper front teeth; interventions - active: any orthodontic brace or head-brace, control: no or delayed treatment or another active intervention; primary outcomes - prominence of the upper front teeth, relationship between upper and lower jaws; secondary outcomes: self esteem, any injury to the upper front teeth, jaw joint problems, patient satisfaction, number of attendances required to complete treatment.

DATA COLLECTION AND ANALYSIS

Information regarding methods, participants, interventions, outcome measures and results were extracted independently and in duplicate by two review authors. The Cochrane Oral Health Group's statistical guidelines were followed and mean differences were calculated using random-effects models. Potential sources of heterogeneity were examined.

MAIN RESULTS

The search strategy identified 185 titles and abstracts. From this we obtained 105 full reports for the review. Eight trials, based on data from 592 patients who presented with Class II Division 1 malocclusion, were included in the review.Early treatment comparisons: Three trials, involving 432 participants, compared early treatment with a functional appliance with no treatment. There was a significant difference in final overjet of the treatment group compared with the control group of -4.04 mm (95% CI -7.47 to -0.6, chi squared 117.02, 2 df, P < 0.00001, I(2) = 98.3%). There was a significant difference in ANB (-1.35 mm; 95% CI -2.57 to -0.14, chi squared 9.17, 2 df, P = 0.01, I(2) = 78.2%) and change in ANB (-0.55; 95% CI -0.92 to -0.18, chi squared 5.71, 1 df, P = 0.06, I(2) = 65.0%) between the treatment and control groups. The comparison of the effect of treatment with headgear versus untreated control revealed that there was a small but significant effect of headgear treatment on overjet of -1.07 (95% CI -1.63 to -0.51, chi squared 0.05, 1 df, P = 0.82, I(2) = 0%). Similarly, headgear resulted in a significant reduction in final ANB of -0.72 (95% CI -1.18 to -0.27, chi squared 0.34, 1 df, P = 0.56, I(2) = 0%). No significant differences, with respect to final overjet, ANB, or ANB change, were found between the effects of early treatment with headgear and the functional appliances. Adolescent treatment (Phase II): At the end of all treatment we found that there were no significant differences in overjet, final ANB or PAR score between the children who had a course of early treatment, with headgear or a functional appliance, and those who had not received early treatment. Similarly, there were no significant differences in overjet, final ANB or PAR score between children who had received a course of early treatment with headgear or a functional appliance. One trial found a significant reduction in overjet (-5.22 mm; 95% CI -6.51 to -3.93) and ANB (-2.27 degrees; 95% CI -3.22 to -1.31, chi squared 1.9, 1 df, P = 0.17, I(2) = 47.3%) for adolescents receiving one-phase treatment with a functional appliance versus an untreated control.A statistically significant reduction of ANB (-0.68 degrees; 95% CI -1.32 to -0.04, chi squared 0.56, 1 df, P = 0.46, I(2) = 0%) with the Twin Block appliance when compared to other functional appliances. However, there was no significant effect of the type of appliance on the final overjet.

AUTHORS' CONCLUSIONS

The evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth is no more effective than providing one course of orthodontic treatment when the child is in early adolescence.

Histological and histomorphometric investigation of the condylar cartilage of juvenile pigs after anterior mandibular displacement

The condylar cartilage of the mandible is considered a secondary growth center and represents a joint cartilage different from other cartilage structures regarding its histological structure, its histochemical and immunohistochemical properties and its growth pattern. This study aimed to histologically and histomorphometrically investigate the condylar cartilage after anterior mandibular displacement similar to functional orthopedic treatment. A total of 12 pigs (sus scrofa domesticus) aged 10 weeks were divided into an experimental group and a control group comprising 6 animals each. The experimental animals were provided bilaterally with synthetic occlusal build-ups in the posterior area which induced anterior displacement of the mandible in terminal occlusion. After 4 weeks, the temporomandibular structures were removed en bloc and the condylar cartilage was analyzed histologically and histomorphometrically. As a result, the experimental animals displayed a significantly increased total cartilage thickness of the posterocranial mandibular condyle which was primarily caused by an increase in thickness of the hypertrophic and chondogenic layers. Similarly, the proliferative layer showed a significant increase, whereas significant differences in thickness were absent in the articular layer. Increased cell proliferation was not observed in the experimental animals as compared to the controls. The changes found in the condylar cartilage area suggest that the zonal structure of the condylar cartilage may be modified by an altered spatial relationship between the mandibular condyle and the glenoid fossa.

Soft-tissue changes during facial growth in skeletal Class II individuals

INTRODUCTION

In orthodontic treatment, a harmonious soft-tissue profile can be difficult to achieve; the thickness of the soft tissues can vary greatly, and changes with growth and treatment can be difficult to predict. The purpose of this study was to investigate changes in the thickness and the length of the soft tissues of the nose, upper and lower lips, and chin due to growth from 6 to 16 years of age.

METHODS

Cephalograms of 36 subjects (22 boys, 15 girls) with skeletal Class II malocclusions were analyzed. They participated in the Burlington Growth Study, and longitudinal records had been collected at ages 6, 9, 12, 14, and 16 years. The cephalograms were digitized and analyzed with Dentofacial Planner Plus (version 2.0; Dentofacial Software, Toronto, Ontario, Canada) software. Statistical analysis was performed with the nonparametric Friedman test, and comparisons among means were made with 1-way ANOVA software.

RESULTS

All structures showed some growth at all stages. The nose showed the greatest increases in thickness and length in both sexes. There was sexual dimorphism at 16 years, with higher values for boys. Upper lips tended to reduce in the girls. Upper lip length showed slight increases, and base of the upper lip showed small increases for both sexes. The lower lip had moderate increases in all measurements, and its thickness showed sexual dimorphism at almost all ages. The soft tissues of the chin increased in both thickness and length, with no sexual dimorphism.

Effects of activator and high-pull headgear combination therapy: skeletal, dentoalveolar, and soft tissue profile changes

The aim of this study was to evaluate skeletal, dentoalveolar, and soft tissue profile changes with activator and high-pull headgear combination therapy in patients with Class II malocclusions caused by maxillary prognathism and mandibular retrognathism. The subjects, all in the mixed dentition, were selected from a single centre and were divided into two groups: 28 patients were treated with an incisor double capping activator and a high-pull headgear combination appliance (13 girls, 15 boys mean chronological age 11.7 +/- 1.2 years, skeletal age 12.1 +/- 1.4 years) and an untreated group of 28 subjects (14 girls, 14 boys mean chronological mean age 11.9 +/- 1.1 years, skeletal age 12.3 +/- 1.3 years). The skeletal, dentoalveolar, and soft tissue profile changes that occurred were compared on lateral cephalograms taken before treatment (T0) and after 1.1 +/- 0.3 years when the combination appliance was removed (T1). In the control group, the radiographs were obtained at the start (T0) and after an observation period 1.2 +/- 0.4 years (T1). Statistical analysis was undertaken with Wilcoxon's ranked-sum test for intra-group comparisons and differences between groups with t-test and Bonferroni's test at a level of significance of P < 0.05. Activator and high-pull headgear combination treatment in these growing patients resulted in a correction of the skeletal Class II relationship (ANB -3.4 degrees), a restriction of maxillary growth (SNA -2.0 degrees, OLp-A -2.3 mm), an advancement of the mandibular structures (SNB +2.6 degrees, FH-NPg +2.3 degrees, OLp-B +2.7 mm, OLp-Pg +2.2 mm), an increase in lower face height (ANS-Me +3.9 mm), a correction of the overjet (-5.4 mm), an improvement in overbite (-2.2 mm), uprighting of the maxillary incisors (U1-FH -5.3 degrees, OLp-U1 -2.5 mm), protrusion of the mandibular incisors (IMPA +2.0 degrees, OLp-L1 +2.7 mm), and a correction of the dental Class II malocclusion (OLp-L6 +3.5 mm). The soft tissue profile changes were a correction of facial convexity (G'-Sn-Pg' angle 2.3 degrees, Mlf-Li-x-axis angle 9.1 degrees), and an increase in lower antero-posterior (Mlf-y-axis 5.6 mm, Pg'-y-axis 5.3 mm), and lower vertical (Sls-x-axis 3.8 mm, Pg'-x-axis 3.8 mm, Me'-x-axis 5.1 mm) soft tissue dimensions. The mentolabial fold depth (Mlf-E line) also significantly decreased, -0.8 mm in the treated group. The activator and high-pull headgear combination appliance was effective in treating growing patients with maxillary prognathism, mandibular deficiency, and facial convexity by a combination of skeletal and dentoalveolar changes and improvement in the soft tissue facial profile.

Skeletal and dentoalveolar effects of Twin-block and bionator appliances in the treatment of Class II malocclusion: a comparative study

INTRODUCTION

The purpose of this study was to evaluate the skeletal and dentoalveolar effects of the Twin-block and bionator appliances in the treatment of Class II Division 1 malocclusions.

METHODS

Fifty-five girls from North India with Class II Division 1 malocclusion and the same physical growth maturation status were selected for the study. The subjects were divided among a Twin-block group (n = 25), a bionator group (n = 20), and a control group (n = 10). Pretreatment and posttreatment lateral cephalometric radiographs of the treatment group subjects, and prefollow-up and postfollow-up radiographs of the control group subjects, were traced manually and subjected to the pitchfork analysis.

RESULTS

Statistical software was used for 1-way analysis of variance and multiple comparisons (post-hoc test, Bonferroni). A P value of .05 was considered statistically significant. Neither the Twin-block nor the bionator appliance significantly restricted forward growth of the maxilla (P = .476). Mandibular growth in the Twin-block subjects was significantly greater than in controls (P = .005). Mandibular growth was comparable in the control and the bionator subjects. Molar correction, overjet reduction, and proclination of the mandibular incisors were significantly greater (P = .000) in the treated subjects compared with the controls.

CONCLUSIONS

Both the Twin-block and bionator appliances were effective in correcting molar relationships and reducing overjets in Class II Division 1 malocclusion subjects. However, the Twin-block was more efficient than the bionator in the treatment of Class II Division 1 malocclusion.

Predictors of long-term orthodontic side effects from mandibular advancement devices in patients with snoring and obstructive sleep apnea

INTRODUCTION

Orthodontic side effects can complicate the long-term use of mandibular advancement devices (MADs) in the treatment of patients with snoring and obstructive sleep apnea. The aim of this study was to find predictors of dental side effects from monoblock MADs.

METHODS

Four hundred fifty patients, who consecutively received treatment with either soft elastomeric or hard acrylic devices, were followed up after 5.4 +/- 0.8 years (mean +/- SD). The continuing patients responded to questionnaires and had dental examinations and plaster casts made.

RESULTS

Twenty-seven patients had moved or died during the follow-up period. Two hundred thirty-six of the remaining 423 patients (56%) continued treatment, and 187 of them reported compliance rates of > or = 50% at night. A small reduction in overjet of < 1 mm was associated with a deepbite with an overbite of > 3 mm and an overjet of < or = 3 mm (odds ratio [OR] = 7.5; P = .015), nasal congestion (OR = 2.9; P = .005), or the use of a soft elastomeric device (OR = 2.7; P = .014) controlled for age, sex, treatment time, and mandibular displacement. A small reduction in overbite of < 1 mm was related to a small opening of the mandible of < 11 mm (OR = 2.5; P = .008).

CONCLUSIONS

Orthodontic side effects might be predictable on the basis of initial characteristics in dental occlusion and the design of MADs.

Retrospective analysis of long-term stable and unstable orthodontic treatment outcomes

INTRODUCTION

The purpose of this study was to compare groups of patients with the most stable and the most unstable treatment results as rated by the peer assessment rating (PAR) index to identify factors associated with stability. All factors with significant crude odds ratios were investigated to create a multiple logistic regression model that could be used to predict stability.

METHODS

The sample of 86 patients (30 male, 56 female), from the post-retention archives at the University of Washington, was not restricted to specific malocclusion types or treatment modalities with the exception of Angle Class III patients, who were excluded. The sample was divided into 2 groups, stable (n = 45) and unstable (n = 41), based on post-retention unweighted PAR scores and PAR score changes between posttreatment and post-retention. Model and radiographic measurements were made before treatment, after treatment, and after retention (average 14.4 years).

RESULTS

The results showed that male sex and a sustained period of growth were related, and both were associated with increased instability. The initial severity of malocclusion, as graded by the PAR index and the irregularity index, was negatively correlated with post-retention stability-ie, patients with more severe index scores before treatment tended to be less stable. Differences in American Board of Orthodontics scores after treatment were diminished after retention.

CONCLUSIONS

The factors associated with predicting stability were pretreatment arch length, pretreatment PAR score, molar classification, and sex.

Effects of activator and activator headgear treatment: comparison with untreated Class II subjects

The aims of this study were to determine whether the activator and activator headgear encourage mandibular growth, and whether there is any superiority of one appliance over the other or if the resultant changes are due to normal growth. Forty-nine skeletal Class II division 1 patients were selected. Thirty-three (13 females, 20 males; mean age 12.52 +/- 1.42 years) were treated with an Andresen activator and the remaining 16 (7 females, 9 males; mean age 13.04 +/- 1.47 years) with an activator headgear combination. Twenty Class II subjects (9 females, 11 males; mean age 12.57 +/- 1.11 years) who had previously refused treatment served as a control group. Cephalometric landmarks were marked and digitized by one author to avoid inter-observer variability. Nine angular and 12 linear measurements were established and measured using Vistadent AT software. A paired-sample t-test and an ANOVA test were used to statistically evaluate the findings. The results revealed that both the activator and the activator headgear combination significantly (P < 0.001) encouraged mandibular growth, but had little restraining effect on the maxilla. The mandibular incisors were more controlled in the activator headgear combination group. The resultant skeletal, dentoalveolar and soft tissue changes differed significantly from those due to growth.

Skeletal effects of bite jumping therapy on the mandible - removable vs. fixed functional appliances

AUTHORS: Shen G, Hagg U, Darendeliler MA.

OBJECTIVE

Based on an extensive review of the literature, the aim of this study was to explore the mainstream consensus on the controversial topic of whether the bite jumping treatment could enhance mandibular growth.

DESIGN

The data for removable and fixed functional appliances were respectively comprehended and analyzed with regard to their attributes in mandibular growth modification. Furthermore, numerous reported findings were assessed by relating them to some important factors influencing the effects of bite jumping, such as treatment timing, treatment duration and post-treatment follow-up, to allow for a more objective and accurate evaluation.

RESULTS

The key differences between removable and fixed appliances are working hours (intermittent vs. continuous), length of treatment time (long vs. short), optimal treatment timing (before puberty growth vs. at or after puberty spurt), and mode of bite-jumping (considerable vertical opening vs. limited vertical opening). These different features lead to different treatment effects on mandibular and TMJ growth, such as the intensity of possibly increased growth (clinically less significant vs. significant), the direction of enhanced growth (vertical vs. horizontal), and the stability of treatment changes (unstable vs. stable). The short-term or long-term post-treatment relapse mainly relates to the rebound of dental position.

CONCLUSION

The immediate effects of bite jumping functional appliances on the mandibular growth enhancement are convincing during actual treatment. This extra gain of growth might be sustainable during the short-term and long-term post-treatment period.

Activator versus cervical headgear: superimpositional cephalometric comparison

Clinical trials comparing activator and headgear treatment have shown comparable effectiveness in the total result achieved, but the mechanism of correction is still uncertain. Most studies have used conventional cephalometric methods to evaluate treatment effects, and this might be a factor for the inconclusive results. The aim of this retrospective investigation was to compare the effects of activator and cervical headgear treatment with a superimpositional cephalometric method that could discern between vertical and horizontal effects as well as skeletal, dental, and rotational treatment results. The sample consisted of 2 groups of Class II Division 1 patients, treated without extraction by the same clinician (22 patients were treated with a modified activator-type functional appliance, and 30 patients were treated with a combination of cervical headgear and fixed edgewise appliances). Lateral cephalometric radiographs taken at the beginning of treatment and after Class II molar correction were evaluated conventionally and with a superimpositional method. Regarding the conventional cephalometric measurements, the only difference in the anteroposterior dimension between the 2 treatment modalities was the significantly reduced SNA angle in the headgear group. Both appliances appeared to produce minimal changes in FMA and GoGn-SN angles, and there were no statistically significant differences between the treatment groups. Regional superimpositions showed differences in the movement of molars: the maxillary molar was found to move more posteriorly and inferiorly in the headgear group. Conversely, the mandibular molar was found to move toward the occlusal plane more in the activator group. Assessment of mandibular skeletal changes showed that the mandible moved anteriorly by approximately 1 mm more in the activator than in the headgear group. The overall effect of the 2 appliances was found to be clinically comparable. However, the individual components of change showed differences characteristic of each appliance.

Diagnostic image analyses of activator treated temporomandibular joint in growth and maturing stages

This study evaluates the condylar response to activator in growth and in maturing patients using radiographs and magnetic resonance images (MRI). Seven patients (four in growth and three in maturing stages) treated for mandibular distal occlusion were studied. In all seven patients, lateral roentgen cephalograms, panoramic radiograms, and MRIs were made before and following functional treatment. All patients' mandibles advanced during treatment. Downward and forward mandibular growth was observed by superimposition of lateral cephalograms. On the condylar posterosuperior regions for both groups, double contours were sometimes observed on the panoramic radiograms following therapy. These double contours coincided with an area of high intensity in the MRIs for both groups. In the mature adult group, the double contours were more clearly observed when compared with those in the growth group. There were differences in the condylar adaptation types between the growth and mature development stages. Condylar adaptation to the newly created mandibular position was nevertheless found even in adult patients.

Comparative study of the Fränkel (FR-2) and bionator appliances in the treatment of Class II malocclusion

The purpose of this investigation was to compare the dentoalveolar and skeletal cephalometric changes produced by the Fränkel (FR-2) and bionator appliances in persons with Class II malocclusion. Lateral cephalograms were available for 66 patients of both sexes, who were divided into 3 groups of 22. The control group included untreated Class II children, with an initial mean age of 8 years 7 months; they were followed without treatment for 13 months. The FR-2 appliance group had an initial mean age of 9 years; those children were treated for a mean period of 17 months. The bionator group initially had a mean age of 10 years 8 months; on average, they were treated for 16 months. The results demonstrated no significant changes in maxillary growth during the evaluation period. Both appliances showed statistically significant increases in mandibular growth and mandibular protrusion, with greater increases in patients treated in the bionator group. Both experimental groups showed an improvement in the maxillomandibular relationship. There were no significant changes in growth direction, while the bionator group had a greater increase in posterior facial height. Both appliances produced similar labial tipping and protrusion of the lower incisors, lingual inclination, retrusion of the upper incisors, and a significant increase in mandibular posterior dentoalveolar height. The major treatment effects of bionator and FR-2 appliances were dentoalveolar, with a smaller, but significant, skeletal effect.

Transition of molar relationships in different skeletal growth patterns

This study investigated maxillary and mandibular growth differences and their effect on the changes in molar relationships from early transitional dentition to adult permanent dentition. Various landmarks were identified and measurements made on the longitudinal cephalometric radiographs of 40 people. The subjects were classified into 3 groups based on the amount of sagittal skeletal growth difference between the jaws. In group A, the mandible grew more than did the maxilla; in Group B, growth was about the same; and in group C, the maxilla grew more than did the mandible. The results revealed that skeletal growth differences between the jaws significantly influenced the changes in molar relationship during the transitional dentition, not only by translating basal bones but also by altering the amount of physiologic mesial shift in the dentition. However, the skeletal growth difference during the permanent dentition did not influence the changes in molar relationship. The sagittal growth difference between the jaws was largely absorbed by a dentoalveolar compensation. Tooth movement showed different characteristic features depending on the amount of the skeletal growth difference: (1) If the mandible grew more than did the maxilla, the growth difference was mostly absorbed by mesial displacement of the maxillary first molars and counterclockwise rotation of the occlusal plane. Anterior occlusion was adjusted by mesial displacement and labial inclination of the maxillary incisors and lingual inclination of the mandibular incisors. (2) If the maxilla grew more than did the mandible, the growth difference was mainly absorbed by mesial displacement of the mandibular molars. Then the maxillary molars showed minimal mesial displacement. The occlusal plane also showed minimal rotational change. Anterior occlusion was adjusted by lingual tipping of the maxillary incisors and mesial displacement and labial tipping of the mandibular incisors.

Effectiveness of early treatment of Class II malocclusion

The purpose of this study was to examine and report the effectiveness of early treatment with the headgear/biteplate and the bionator in patients with Class II malocclusion regardless of the mechanism of correction and to compare early-treatment results with changes over a similar time period in an observation group. The role of factors such as compliance was examined to determine their contribution to effective treatment. The experimental design was a prospective, longitudinal, randomized controlled trial. At the end of the early-treatment period, all 3 groups differed significantly (overall, P = .001) in percentage of treatment goal achieved, with median values of 83% for the bionator group, 100% for the headgear group, and 14% for the observation group. In both treated and observation subjects, the percentages of goal achieved varied by initial molar class severity (treated, P =.0205; observation, P = .0040) and race (treated, P = .0314; observation, P = .0416). Significant correlations in the treated subjects were identified between percentage of goal achieved and bone age (13 bones) (r = 0.16; P = .037), bone age (20 bones) (r = 0.16; P = .043), compliance (r = 0.26; P = .0005), and initial overjet (r = -0.26; P = .0095). Significant correlations were not detected in the observation group. Sex, treatment group, age, mandibular plane angle, pretreatment, and retention did not significantly affect percentage of goal achieved among the treated and the observation subjects. Correlation between normalized compliance scores and percentage of goal achieved was high for both bionator (r = 0.50) and headgear subjects (r = 0.49) at the end of treatment. Multivariate analysis suggested that headgear may be superior to bionator/biteplane in achieving a Class II correction during early treatment.

An assessment of skeletal and dental responses to the functional magnetic system (FMS)

Correction of a skeletal Class II malocclusion with functional appliances has been accepted as a viable treatment modality. However, its mechanism of action is still disputed. This retrospective study compared 20 Class II patients treated with the functional magnetic system (FMS) with Class I and Class II groups (the control groups) of 20 untreated subjects each. Dental and skeletal changes were compared using serial lateral cephalograms. The FMS group differed significantly from the control groups in 15 of 24 parameters. The great increase in articulare-gnathion distance (3.07 mm) attributed to the attractive magnetic component of the FMS dictates a prolonged propulsion of the mandible. The skeletal:dental response ratio was 1:2 for the anterior region and 1:1 for the posterior region. The dental and skeletal parameters demonstrated a synergistic response in the maxilla and a competitive response in the mandible. This means that greater maxillary molar distal movement and incisor retroclination resulted in a more significant restraint of point A. In contrast, increasing the mandibular molar mesial movement and the incisor proclination accompanied less advancement of the pogonion. Although the skeletal contribution to the resolution of the malocclusion was less than the dental contribution (anteriorly, one third), the functional correction response was found to be regulated by skeletal factors.

Three-dimensional evaluation of skeletal and dental asymmetries in Class II subdivision malocclusions

The objective of this study was to determine if any significant differences existed with regard to dental and skeletal asymmetries between subjects with Angle Class II subdivision malocclusions and subjects with normal occlusions. The sample consisted of 30 subjects in each of the 2 groups. Each possessed a full complement of permanent teeth, including first molars. The average age of subjects was 15.76 years in the Class II subdivision group and 22.42 years in the normal occlusion group. Measurements were obtained with the use of submentovertex, posteroanterior, and corrected oblique cephalometric radiographs. In the submentovertex radiographs, symmetry was assessed by measuring the relative differences in the spatial positions of dental and skeletal landmarks between the right and the left sides in both anteroposterior and transverse dimensions. Coordinate systems were used to represent the mandible, cranial floor, and the maxilla. In the posteroanterior radiographs, symmetry was assessed similarly by measuring the relative differences in the spatial positions of dental and skeletal landmarks between the right and the left sides. In the corrected oblique radiographs, symmetry was assessed by measuring the differences in size of dental and skeletal structures between the right and the left sides. Variables were analyzed with multivariate logistic regression analysis. The results demonstrated that the primary contributor to the differences between the 2 groups was the distal positioning of the mandibular first molars on the Class II side in patients whose mandibles showed no unusual skeletal or positional asymmetries. A secondary contributor was the mesial positioning of the maxillary first molars on the Class II side. Furthermore, the posteroanterior radiographic analysis showed that the more frequent distal positioning of the mandibular molars on the Class II side, compared with the mesial positioning of the maxillary molars on that side resulted in mandibular dental midline deviation to the Class II side more frequently than the maxillary dental midline to the opposite side.

Improved clinical use of Twin-block and Herbst as a result of radiating viscoelastic tissue forces on the condyle and fossa in treatment and long-term retention: growth relativity

Understanding mechanisms of action for orthopedic appliances is critical for orthodontists who hope to treat and retain the achieved corrections in patients with initial Class II mandibular retrognathism. That knowledge can help orthodontists produce clinically significant bone formation and avoid compression at the condyle-glenoid fossa region. It also assists us to understand the differences between short-term and long-term treatment results. It was previously thought that increased activity in the postural masticatory muscles was the key to promoting condyle-glenoid fossa growth. By analyzing results from several studies, we postulate that growth modification is associated with decreased activity, which leads to our nonmuscular hypothesis. This premise has its foundation on 3 key specific findings: significant glenoid fossa bone formation occurs during treatment that includes mandibular displacement; glenoid fossa modification is a result of the stretch forces of the retrodiskal tissues, capsule, and altered flow of viscous synovium; observations that glenoid fossa bone formation takes place a distance from the soft tissue attachment. The latter observation is explained by transduction or referral of forces. Evidence is presented, therefore, that the 3 trigger switches for glenoid fossa growth can similarly initiate short-term condylar growth modifications because the 2 structures are contiguous. These are displacement, several direct viscoelastic connections, and transduction of forces. Histologic evidence further shows that stretched retrodiskal tissues also insert directly into the condylar head's fibrocartilaginous layer. The impact of the viscoelastic tissues may be highly significant and should be considered along with the standard skeletal, dental, neuromuscular, and age factors that influence condyle-glenoid fossa growth with orthopedic advancement. These biodynamic factors are also capable of reversing effects of treatment on mandibular growth direction, size, and morphology. Relapse occurs as a result of release of the condyle and ensuing compression against the newly proliferated retrodiskal tissues together with the reactivation of muscle activity. To describe condyle-glenoid fossa growth modification, an analogy is made to a light bulb on a dimmer switch. The condyle illuminates in treatment, dims down in the retention period, to near base levels over the long-term.

Do we really want a quick fix?

Dental practitioners have been encouraged recently to take a more structured long term view of their continuing professional development, in particular being wary of any 'weekend' courses apparently offering 'quick fix' solutions to their clinical problems.

Eruption Guidance Appliance effects in the treatment of Class II, Division 1 malocclusions

The objective of this research was to cephalometrically evaluate the possible effects of the Eruption Guidance Appliance on the craniofacial complex in a sample of 30 patients, over a treatment period of 26 months. The experimental sample consisted of 30 patients (13 females and 17 males), 27 of which presented with a Class II, Division 1 malocclusion and 3 with a Class I malocclusion. The mean initial chronologic age was 9 years; the treatment period lasted 26 months. A control group was used for comparison and consisted of 30 subjects (13 females and 17 males) of similar ages and spanned a similar observation period. Twenty-six subjects of this control group had Class II, Division 1 malocclusions, and 4 had Class I malocclusions. Lateral cephalometric headplates were obtained for the experimental group initially and after 26 months of treatment. The subjects in the control group were randomly selected from a serial growth study sample from the Orthodontic Department at Bauru Dental School, University of São Paulo, for whom cephalometric headplates were obtained annually from 4 to 18 years of age. Comparative statistics were used to assess possible differences between the experimental and control groups during the 26-month period of observation. Results demonstrated statistically significant increases in mandibular growth, degree of mandibular protrusion, lower anterior and total anterior face height, mesial migration of the lower molars, and mandibular posterior dentoalveolar height. There was also lingual tipping and retrusion of the upper incisors, linear protrusion of the lower incisors, improvement in the maxillomandibular relationship and in molar relationship, as well as a significant decrease in the overjet and overbite and an inhibition of the vertical development of the upper incisors. The study demonstrated no significant changes in maxillary growth during the evaluation period. It was concluded from these results that the effects of the Eruption Guidance Appliance during this time period were mostly dentoalveolar, with a smaller, but significant, skeletal effect.

Muscle response to the twin-block appliance: an electromyographic study of the masseter and anterior temporal muscles

An electromyographic study was performed on 10 young growing girls in the age group of 9 to 12 years with Class II Division 1 malocclusion and retruded mandible, who were under treatment with Twin-block appliances. Bilateral EMG activity of elevator muscles of the mandible (ie, anterior temporalis and masseter) was monitored longitudinally with bipolar surface electrodes to determine changes in postural, swallowing, and maximal voluntary clenching activity during an observation period of 6 months. The changes were noted at the start of treatment (0 month), within 1 month of Twin-block insertion, at the end of 3 months, and at the end of 6 months. The results revealed a significant increase in postural and maximal clenching EMG activity in masseter (P <.01) and a numeric increase in anterior temporalis activity during the 6 month period of treatment. The increased electromyographic activity can be attributed to an enhanced stretch (myotatic) reflex of the elevator muscles, contributing to isometric contractions. The main force for Twin-block treatment appears to be provided through increased active tension in the stretched muscles (motor unit stimulation) and from initiation of myotatic reflex activity and not through passive tension (viscoelastic properties) of jaw muscles. The results of this study reaffirm the importance of full-time wear for functional appliances to exert their maximum therapeutic effect by way of neuromuscular adaptation.

Comparison of the effects of monoblock and twin-block appliances on the skeletal and dentoalveolar structures

Functional appliances, which are used in the early treatment period of skeletal Class II malocclusions, induce the forward displacement of the mandible by altering the postural activity of the muscles and causing some changes in both skeletal and dentoalveolar structures. The purpose of this investigation was to evaluate the differences between monoblock and twin-block appliances. Two treatment groups composed of 26 growing patients with skeletal and dental Class II, Division 1, malocclusions, were compared to an untreated control group of 13 patients with the same morphologic characteristics and growth rate. These groups were matched according to their age, sex, and vertical and sagittal skeletal cephalometric and dental characteristics. Monoblock was worn by the subjects for 16 hours/day, whereas twin-block was worn 24 hours/day, even while eating. Patients of the control group were followed without any intervention. Treatment effects were identified with a conventional cephalometric analysis. The findings of this study revealed that by using these different functional appliances, the stimulation of the growth of the lower jaw and the correction of Angle Class II relationship were achieved. In the twin-block group, the mandibular plane angle and gonial angle increased, although a decrease in the degree of overbite occurred. In the monoblock group, upper incisors demonstrated a greater degree of retrusion. However, within the twin-block group, the lower incisors showed a greater degree of proclination.

Effectiveness of intra- and extraoral aids to the bionator. A controlled study within the scope of the "Wuerzburg concept"

A bimaxillary device is effective only if the therapeutic position of the mandible is maintained for as long a period as possible by day and night, i.e. the lower jaw cannot "drop" from the construction bite position. One simple means of preventing the mandible from dropping out of the bimaxillary appliance during sleep and thus of ensuring adaptation of the muscles and of the joint structures during the night without impairing active adaptation during daytime functions (speaking, swallowing) is being used at Wuerzburg University Department of Orthodontics: In connection with anterior traction, which anchors the bimaxillary appliance to the maxilla, attachments are fixed to the mandibular canines or first premolars, so that the mandible is kept in the therapeutic position during the night by means of elastics. Besides the description of this method, the results of a clinical study on its effectiveness are presented in this paper. In the experimental group (20 Class II/1 patients) treated with the combination of bionator with anterior extraoral traction and up-and-down elastics, the increase of the SNB angle and accordingly of the ANB angle was twice as great as in a control group treated only with bionator and extraoral traction without additional securing of the mandible.

Stability of skeletal changes after activator treatment of patients with class III malocclusions

The aim of this study was to examine the skeletal changes produced by Class III activator during the treatment of patients with skeletal Class III malocclusions and to characterize the stability of these changes in the years after treatment. The samples consisted of 19 girls and 9 boys. Their mean age was 9.6 +/- 1.4 years at the beginning of the treatment. The average treatment time was 1 +/- 0.5 years. Measurements were obtained from cephalometric head films taken before treatment, at the end of treatment, and 6.6 +/- 2.1 years after the end of activator treatment. During the treatment, the Class III activator produced a statistically significant increase in the ANB angle, and this change remained through the postactivator period. The gonial angle exhibited a compensatory decline during the postactivator period. The skeletal profile was improved with treatment and was not lost during the posttreatment period despite significant increase in maxillomandibular differential. This study indicates that Class III activator may be a viable mode for the initial stage of skeletal Class III treatment, in conjunction with the period of postfunctional fixed or removable appliance therapy to improve the occlusion.