Vertical and sagittal morphology of the facial skeleton and the pharyngeal airway

AIM

The aim of this study was to evaluate the relationship between sagittal and vertical facial skeletal morphology, and the morphology of the upper and lower pharyngeal airway.

MATERIAL AND METHODS

Pharyngeal airway structures were studied in 101 healthy children (36 boys and 65 girls) aged 7-17 years who were referred for orthodontic treatment. The sample was divided into two groups: according size of the ANB angle group Class I: angle till 4º was considered as skeletal Angle Class I; group Class II: ANB angle more than 4º, considered as skeletal Angle Class II. The vertical pattern was classified using the SN-MP angle, with angle less than 34 taken as normal, and more than 34 - as high vertical growth patterns. The linear measurements and angles were calculated using special purpose software (Dolphin v. 11.0). Pharyngeal width was measured at different point levels using Arnett/Gunson airway analysis.

RESULTS

A statistically significant difference between the two groups, and airway width on all levels was statistically significantly narrower in Angle Class II. Pearson's correlation coefficient showed a negative statistically significant dependence between nasopharyngeal airway, oropharyngeal airway space, and SN-MP angle.

CONCLUSION

Statistically significantly narrower airways were found in patients with ANB more than 4°. In groups divided by SN-MP angle statistically significant difference have not found. Nasopharyngeal airway and oropharyngeal airway spaces statistically significantly negatively correlated with the SN-MP angle: the bigger the SN-MP angle, the smaller were nasopharyngeal and oropharyngeal airway spaces.

Sagittal lip positions in different skeletal malocclusions: a cephalometric analysis

BACKGROUND

The objectives of this paper are to (1) study use of soft tissue analyses advocated by Steiner, Ricketts, Burstone, Sushner and Holdway to develop soft tissue cephalometric norms as baseline data for sagittal lip position in Northeast Chinese adult population, (2) compare the sagittal lip positions in different skeletal malocclusions and (3) compare the sagittal lip positions in Northeast Chinese adults with other reported populations.

METHODS

Lateral cephalometric radiographs of subjects were taken in natural head position. Radiographs were manually traced and five reference lines - Sushner, Steiner, Burstone, Holdway and Ricketts, were used. The linear distance between the tip of the lips and the five reference lines were measured. Statistical analysis was done using the Statistical Package for Social Sciences (SPSS) 21. Descriptive analysis was done for each variable for each subject. Coefficient of variation between lip positions as assessed by reference lines was determined. Post hoc Tukey's test was used for comparison of the mean cephalometric values of three skeletal malocclusions. The level of significance for the analysis was set at p < 0.05.

RESULTS

The findings showed significant difference in the sagittal lip positions in different skeletal malocclusions. There was variation in consistent reference line in each skeletal malocclusion. The S2 line was the most consistent reference line in skeletal class I and class II group. The B line was the most consistent line in skeletal class III. In skeletal class II group, upper lips were the most protrusive and lower lips were retrusive than in skeletal class I and class III groups. In case of skeletal class III group, upper lips were retrusive and lower lips were more protrusive than in skeletal class I and class II groups.

CONCLUSIONS

The sagittal lip positions were found to be associated with the skeletal malocclusion pattern. Northeast Chinese population has protrusive upper and lower lip in comparison to Caucasians. Each skeletal malocclusion group showed different preferable reference lines for analysis of sagittal lip position.

[Features of the hormonal status in patients with temporomandibular joint dysfunction and class II malocclusion]

The article presents data on androgen levels in female patients with temporomandibular joint (TMJ) dysfunction of varying degree and class II malocclusion. The study revealed significant correlation between degenerative and inflammatory TMJ changes and androgens level in patients with stigmas of connective tissue dysplasia (p<0.05), probably due to indirect proinflammatory action of androgens as they stimulate inflammatory mediators expression.

The Overbite Complexity: How The Vertical Position, Tooth-Size Ratios And Other Factors Affect Occlusion and Overbites

This article explains the complexity of overbites and how to diagnose pre-treatment occlusions to finish orthodontic cases with stable, long lasting occlusion and proper overbites. It explains the changes that occur when overbites deepen and how to correct to proper overbite positions.

Base of the skull morphology and Class III malocclusion in patients with unilateral cleft lip and palate

OBJECTIVE

The aim of the present study was to determine the morphological differences in the base of the skull of individuals with cleft lip and palate and Class III malocclusion in comparison to control groups with Class I and Class III malocclusion.

METHODS

A total of 89 individuals (males and females) aged between 5 and 27 years old (Class I, n = 32; Class III, n = 29; and Class III individuals with unilateral cleft lip and palate, n = 28) attending PUC-MG Dental Center and Cleft Lip/Palate Care Center of Baleia Hospital and PUC-MG (CENTRARE) were selected. Linear and angular measurements of the base of the skull, maxilla and mandible were performed and assessed by a single calibrated examiner by means of cephalometric radiographs. Statistical analysis involved ANCOVA and Bonferroni correction.

RESULTS

No significant differences with regard to the base of the skull were found between the control group (Class I) and individuals with cleft lip and palate (P > 0.017). The cleft lip/palate group differed from the Class III group only with regard to CI.Sp.Ba (P = 0.015). Individuals with cleft lip and palate had a significantly shorter maxillary length (Co-A) in comparison to the control group (P < 0.001). No significant differences were found in the mandible (Co-Gn) of the control group and individuals with cleft lip and palate (P = 1.000).

CONCLUSION

The present findings suggest that there are no significant differences in the base of the skull of individuals Class I or Class III and individuals with cleft lip and palate and Class III malocclusion.

Anterior maxillary dentoalveolar and skeletal cephalometric factors involved in upper incisor crown exposure in subjects with Class II and III skeletal open bite

OBJECTIVE

To compare the anterior dentoalveolar and skeletal maxillary cephalometric factors involved in excessive upper incisor crown exposure (UICE) in subjects with skeletal open bite Class II (SOBCIIG) and Class III (SOBCIIIG) against an untreated control group (CG).

MATERIALS AND METHODS

Seventy pretreatment lateral cephalograms of orthodontic young adult patients (34 men, 36 women) were examined. The sample was divided into three groups according to both sagittal and vertical growth pattern and occlusion. The CG group (n  =  25) included Class I, normodivergent cases with adequate overbite, and the SOBCIIG group (n  =  25) and SOBCIIIG group (n  =  20) included skeletal Class II or III malocclusions, respectively, with hyperdivergent pattern and negative overbite. Several cephalometric measurements were considered (skeletal and dental). Analysis of variance, multivariate analysis of covariance, and Tukey HSD post hoc tests were used. Principal component analysis (PCA) was used for reducing the number of cephalometric variables related to UICE. Finally, a multiple linear regression was calculated.

RESULTS

Significant differences in UICE were found between the groups (P < .05). UICE was 3.9 mm in SOBCIIG, 2.5 mm in SOBCIIIG, and 0.4 mm in CG. PCA showed that a nondental component-including vertical maxillary height (VMH) and upper lip height (ULH)-was the only component significantly associated with UICE. The regression model had a moderate prediction capability.

CONCLUSIONS

Although the UICE was statistically different in SOBCIIG, the values were within the esthetic standards. The UICE was mainly influenced by VMH and ULH.

Mandibular growth comparisons of Class I and Class II division 1 skeletofacial patterns

OBJECTIVE

To determine class and sex differences in mandibular growth and modeling.

MATERIALS AND METHODS

A mixed-longitudinal sample of 130 untreated French-Canadian adolescents, 77 (45 boys and 32 girls) with Class I (normal or abnormal) occlusion and 53 (26 boys and 27 girls) with Class II division 1 malocclusion, was used. Based on eight landmarks, eight traditional measurements were used to compare the anteroposterior position of the maxilla and mandible, relationship between the jaws, and mandibular size. Mandibular superimpositions were used to compare the horizontal and vertical changes of condylion, gonion, and menton.

RESULTS

While there were no differences in maxillary position based on the SNA angle, Class IIs had more retrognathic mandibles than did Class Is. Total mandibular length was greater in Class Is than in Class IIs at 15 years of age. Superior and total growth and modeling changes at condylion and gonion, respectively, were greater for Class Is than Class IIs. Boys were more prognathic than girls; they had larger mandibles and exhibited greater size increases and growth changes than girls did.

CONCLUSIONS

There are both class and sex differences in mandibular growth and modeling.

Morphological characteristics influencing the orthodontic extraction strategies for Angle's class II division 1 malocclusions

BACKGROUND

Extraction has now been accepted widely in various malocclusions including Angle's class II division 1. However, the levels of scientific evidence in orthodontic treatment planning have been weak, and it is unlikely to systematically provide a rationale and consistent basis in decisions of extraction. This study was retrospectively designed to investigate the initial morphologic characteristics of class II division 1 subjects involving four different extraction strategies, to determine the relevant influential factors when choosing extraction strategies with the most commonly used mechanics and the principle of simplicity in orthodontic treatment based on cases diagnosed and treated by an experienced orthodontist.

METHODS

One hundred and ten samples of Angle's class II division 1 malocclusion with good facial and occlusal outcomes after orthodontic treatment were selected and divided into four groups according to different extraction patterns. For each case, pretreatment models and the lateral radiographs were analyzed. Significant variables of models and craniofacial structures of each group were identified by comparing the measurements using one-way analysis of variance (ANOVA) at a significance level of P < 0.05. Then, binary logistic regression analysis was used and a regression equation was established to quantify the correlations among the significant variables and their contributions to the extraction decisions.

RESULTS

Molar relationship, lower anterior crowding, anterior Bolton index, and anterior overjet measured from models, as well as ANS-Xi-Pm, NBa-PtGn, Li-NsPog', U1-NPog and L1-NPog measured from lateral radiographs were found to be statistically significant. Binary logistic regression analysis revealed that lower anterior crowding, molar relationship, and growth pattern were the three most relevant influential factors with a declining impact contributing to the extraction decisions for Angle's class II division 1 malocclusions.

CONCLUSIONS

Angle's class II division 1 malocclusions exhibit various morphological characteristics. Orthodontists should comprehensively consider the reciprocal impact of multiple factors when choosing different extraction strategies for Angle's class II division 1 malocclusions.

Assessment of dental arches in patients with Class II division 1 and division 2 malocclusions using 3D digital models in a Syrian sample

AIM

(1) to evaluate the applicability of using 3D digital models in the assessment of Class II Division 1 (Cl II-1) and Class II Division 2 (Cl II-2) malocclusion in a Syrian sample, (2) to detect any significant differences between the two groups in tooth and arch widths, anterior (ABR) and overall Bolton ratios, PAR Index, and (3) to detect any gender differences in these variables.

DESIGN AND SETTING

observational, cross-sectional study for descriptive and analytical purposes at the Orthodontic Dept., University of Al-Baath Hamah Dental School, Hamah, Syria.

PARTICIPANTS

A disproportionate multi-stratified random sampling was employed to select 36 Cl II-1 and 36 Cl II-2 patients (female-to-male ratio was 1:1 in each group). 3D digital models (O3DM) with a dedicated programme were used to measure dental arch variables.

RESULTS

Significant differences were observed between the two groups in the mesiodistal widths of some teeth but not in the dental arch widths. The prevalence of 'discrepancy cases' in Anterior Bolton Ratios (ABRs) was 33.33% and 41.67% in Cl II1 and Cl II2 groups, respectively. The mean PAR Index score was 25.36 and 20.82 for Cl II1 and Cl II2 groups, respectively (p=0.009).

CONCLUSIONS

(1) 3D digital models enabled fast, accurate and reliable measurements of dental arch characteristics in patients with Class II malocclusion. (2) Insignificant differences between Cl II1 and Cl II2 patients were observed regarding Bolton's ratios and transverse arch measurements. (3) Sexual dimorphism was observed in mesiodistal tooth widths and in dental arch widths, but not in Bolton's ratios and PAR Index scores.

Facial-profile attractiveness changes in adult patients treated with the Herbst appliance

AIM

The goal of this study was to compare facial profile attractiveness changes of adult patients treated with the Herbst appliance assessed by orthodontists and laypeople.

MATERIALS AND METHODS

The patient sample comprised 28 adult Herbst patients. Facial profile photographs of the patients were randomly divided into two evaluation sets (before T0, after treatment T1). Ten members of the Angle Society of Europe (orthodontists) and 10 dental students in their third semester (laymen) rated both sets of photographs using Visual Analog Scales (VAS) with an interval of 1 day between the ratings.

RESULTS

On average, both orthodontists and students found an improvement in facial profile attractiveness through Herbst appliance treatment (VAS T1-T0 = 0.3 ± 1.9 cm). However, the interindividual perception of profile attractiveness varied greatly in the two rater groups. For both time periods (T0, T1), lower VAS ratings were given by students than by orthodontists.

CONCLUSION

Herbst therapy in adult patients generally improves facial profile attractiveness. Students rated facial profiles more critically than orthodontists.

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.

[Contribution of three dimensional cephalometry in the study of determining morphological parameters for facial esthetics]

There have been numerous studies of facial esthetics, but few have benefited from the new techniques provided by 3D imaging. The aim of this study is to determine which are the most crucial cephalometric criteria for facial esthetics by identifying the strongest correlations between the esthetic rating and 3D Cephalometric values, the Cepha 3Dt. A group of 91 subjects (from 10 to 60 years of age) was rated by a jury of 50 randomly selected judges (from 12 to 65 years of age) using an analog scale. We then looked for the most important correlations between the esthetic ratings and the tridimensional cephalometric values by using 3D Cephalometric Analysis on a global sample, and on Class II and Class III sub-samples. Facial esthetics therefore appeared to be especially linked to: anterior-posterior dimension, maxillo-mandibular disharmony, relationships between the anterior areas (alveolar and basal), the alveolar region has a greater impact than the basal area on facial architecture. In the Class II group, sagittal discrepancies and mandibular divergence have an equal impact on the assessment of facial esthetics.

Evaluation of Cervical Spine Posture After Functional Therapy with FR-2: A Longitudinal Study

The authors compared postural changes produced in 20 Caucasian female children treated with the Frankel Functional Regulator appliance (FR-2) (Frankel Industries, Morangis Cedex, France) using cephalometric tracings and comparing the tracings to 20 untreated Class II controls from the University of Chieti. Each patient in the study group was treated for exactly two years by the same operator using the FR-2 appliance and a standardized design and clinical technique, including prefunctional orthodontics where indicated. The average starting age was 8.4 yrs. (SD+/-2.1). At the end of the therapy, the average age was 10.3 yrs. (SD+/-2.4). Two teleradiographs were made of each patient: the first one at the beginning of treatment and the second one after six months. The radiographs were taken with the subjects standing in the ortho-position with no ear rods in the cephalostat; mirror position was carried out. In order to detect errors due to landmark identification, duplicate measurements were made using ten radiographs, and the error variance was calculated using Dahlberg's formula. Thirty-seven variables were studied. The cervical lordosis angle (CVT/EVT) was significantly higher in the study group as compared to the control group (p<0.05) at the end of treatment, probably due to a significant backward inclination of the upper segment of the cervical column (OPTNer and CVTNer) in the treated group (p<0.001 and p<0.01) from pre- to posttreatment. There was no significant change in the lower segment of the cervical column inclination (EVT/Ver). The changes resulted in a weak association in the multiple regression model to an increasing of maxillary base length and mandibular protrusion (R2=0.272; p<0.05). Other variables in the multiple regression were not significant.

The effects of forehead and neck position on esthetics of class I, II and III profiles

INTRODUCTION

All parts of the face, other than jaw relationships, should be considered in orthodontic treatment planning. The role of forehead and neck in facial esthetics is well known; however, the majority of conventional facial analysis methods have not considered them. Neck and forehead may confer mutual effects on equilibrium and on esthetics of other facial components, and may change the overall convexity/concavity view of the profile. Therefore, the aim of this study was to assess the effect of anteroposterior position of the forehead and neck on the esthetics of skeletal class I, II and III jaw relationships using profile silhouettes.

METHODS

Class II and III jaw relationships were constructed on the silhouette of a class I normal profile by altering the mandibular position. Retruded, normal and protruded positions were also applied for the forehead and neck. Three hundred Iranian laypeople (150 men, 150 women) scored the esthetics of profile silhouettes from 1 to 7. Half of the participants were told to consider the profiles as a man, and the other half were told to consider them as a woman. Data were analyzed using non-parametric methods.

RESULTS

Class I jaw relation was found to be the most beautiful profile followed by class II and III respectively. Esthetics of different positions of the neck and forehead were significantly different (P < 0.05). In subjects with a normal neck and forehead position, and those with a retruded neck, the best esthetic relationship was class I, and the worst was class III. For protruded foreheads, the best jaw relationship was class II for females and class I for males, and the worst was class III for both. In a retruded forehead position, the most preferred jaw relationship was class I, and the worst was class II. For profiles with a protruded neck, the best esthetics was found to be in class III jaw relationship, and the worst was in class II. There was a small difference in scoring for male and female profiles (P < 0.05); there were also small differences in scoring trends of men and women (P < 0.05).

CONCLUSION

This study showed that the anteroposterior position of the forehead and neck affects the esthetics of jaw relationships in profile view. In laypeople's opinions, in a normal profile, the overall appearance is more important compared to the independent position of the neck and forehead; however, having jaw abnormalities, the neck plays an important independent role. The preferred jaw relation for profiles with each forehead or neck position was introduced.

[Morphological and radiological features of unilateral class II malocclusion]

The aim of the study was to evaluate the asymmetry of dentition, mandible and bite features in adult patients with unilateral class II malocclusion. The study revealed that class II malocclusion is associated rather with an asymmetrical shift of the mandible to the side with distal molars relation than with absolute dentoalveolar anomaly.

Dental and skeletal components of Class II open bite treatment with a modified Thurow appliance

INTRODUCTION

Due to the lack of studies that distinguish between dentoalveolar and basal changes caused by the Thurow appliance, this clinical study, carried out by the School of Dentistry--State University of São Paulo/Araraquara, aimed at assessing the dental and skeletal changes induced by modified Thurow appliance.

METHODS

The sample included an experimental group comprising 13 subjects aged between 7 and 10 years old, with Class II malocclusion and anterior open bite, and a control group comprising 22 subjects similar in age, sex and mandibular plane angle. Maxillary/mandibular, horizontal/vertical, dental/skeletal movements (ANS, PNS, U1, U6, Co, Go, Pog, L1, L6) were assessed, based on 14 landmarks, 8 angles (S-N-ANS, SNA, PPA, S-N-Pog, SNB, MPA, PP/MPA, ANB) and 3 linear measures (N-Me, ANS-Me, S-Go).

RESULTS

Treatment caused significantly greater angle decrease between the palatal and the mandibular plane on the experimental group, primarily due to an increase in the palatal plane angle. ANB, SNA and S-N-ANS angles significantly decreased more in patients from the experimental group. PNS was superiorly remodeled. Lower face height (ANS-Me) decreased in the experimental group and increased in the control group.

CONCLUSIONS

The modified Thurow appliance controlled vertical and horizontal displacements of the maxilla, rotated the maxilla and improved open bite malocclusion, decreasing lower facial height.

Alveolar and dental arch morphology in Angle Class II division 2 malocclusion: a comparative study

OBJECTIVE

The aim of this study was to analyze the dental and alveolar intercanine, interpremolar and intermolar widths in patients with Class II/2 malocclusion and to compare the data with a patient group with normal occlusion and also with a patient group with Class II/1 malocclusion.

MATERIALS AND METHODS

The study was conducted on 140 untreated patients with permanent dentition, aged 16 to 25 years, which were divided into three groups, according to Angle's classification of occlusion. The measurements of the dento-alveolar intercanine, interpremolar and intermolar widths were made on virtual study models, scanned using an optical 3D scanner. The unpaired (Student's) t-test was used to determine whether there were any significant differences between the Class II/2 and Class I groups and between Class II/2 and Class II/1 groups, respectively (p<0.05).

RESULTS

Significant differences were found between Class II/2 and Class II/1 groups in the maxillary and mandibular intercanine widths. Comparing the Class II/2 and Class I groups, significant differences were found in the mandibular intercanine width, in the maxillary and mandibular interpremolar widths and also in the maxillary and mandibular intercanine and interpremolar alveolar widths.

CONCLUSIONS

The maxillary and mandibular interpremolar widths and the intercanine and interpremolar alveolar widths were larger, while the mandibular intercanine width was shorter in the Class I group than in the Class II division 2 group. The mandibular intercanine width was longer and the maxillary intercanine width was shorter in the Class II division 1 group compared to the Class II division 2 group.

The influence of functional therapy on facial and dental structures. Case presentation

In the era of fixed appliances, some orthodontic practitioners seem to forget about functional therapy. Functional appliances are the only capable of orthopedically changes during the growth spurt. Activators of all types, classic or opened, are elected appliances in growing subjects with class II/1 anomalies. The appropriate case selection, along with patient compliance, lead to improved facial aesthetic and dental occlusion, at affordable prices. With this case presentation, we want to show our protocol in the management of these cases.

The upper airway dimensions in different sagittal craniofacial patterns: a systematic review

OBJECTIVE. Upper airway changes caused by orthognathic surgery operations have been a topic of a concern in the orthodontic literature because of a possible development of obstructive sleep apnea. Diverse response of the airway patency could be expected if the dimensions of the airway differ among various malocclusions already before orthognathic treatment. However the associations between facial morphology and the upper airway dimensions have not been clarified. The purpose of this systematic review was to elucidate whether the upper airway dimensions differ among various sagittal craniofacial patterns. MATERIAL AND METHODS. MEDLINE and the Cochrane Library were searched up to November 2012. Reference lists of relevant articles were checked for further possible studies. Strict inclusion and exclusion criteria were applied when considering the studies to be included. Screening of eligible studies and data extraction were conducted independently by two reviewers. RESULTS. 758 studies were identified and 11 of these were recognized as suitable for further analysis. 75% of studies did not find differences in the nasopharyngeal dimensions among craniofacial patterns. The findings for the oropharyngeal dimensions were controversial as 5 of 11 investigations found these to be smaller in Class II subjects, and 6 of 11 concluded that oropharynx size is larger in Class III pattern. The vertical growth type of the subjects was not considered in five investigations, and 45% of the included studies used lateral cephalometry as only tool for airway assessment. CONCLUSIONS. Currently there is insufficient evidence that the upper airway dimensions differ in various sagittal skeletal patterns.

Craniofacial morphology in patients with Angle Class II division 2 malocclusion

Cephalometric analysis is frequently used in orthodontics for diagnostic purposes, in order to evaluate the positional relationship of the upper and lower jaw to the cranial base, as well as to objectively asses the way dental arches relate to one another and to the skeletal base. As with other dento-skeletal anomalies, the normal growth process can induce changes in these parameters. The purpose of this study is to evaluate the skeletal and dental changes that occur in growing patients with Angle Class II division 2 malocclusion. The study also focuses on analyzing and comparing several parameters in three groups of young patients of different ages, diagnosed with Class II division 2 malocclusion, in order to determine whether the anomaly worsens or improves during the patients' growth period. A total of 25 lateral skull teleradiographs were analyzed using cephX. The patients were divided into three groups (Group 1: 6-8 years, Group 2: 9-14 years, Group 3: 15-18 years). We used the cephalometric parameters described in Björk-Jarabak and Tweed analyses, as well as the relationship of the upper and lower central incisors to the skeletal landmarks. The statistical methods used in this study were the analysis of variance (ANOVA) and the unpaired Student's t-test (p<0.05). We concluded that, during the physiological growth process, the Angle Class II division 2 malocclusion has the following cephalometric characteristics: the maxillary central incisors were in accentuated retroclination, the interincisal angle was very obtuse, the gonial angle showed lower than normal values towards the end of the growth period, the lower anterior face height was definitely decreased, the mandibular body length was shorter than normal in the early growth period and the tendency towards a hypodivergent skeletal pattern remained stable during growth.

Short-term pharyngeal airway changes after mandibular advancement surgery in adult Class II-Patients--a three-dimensional retrospective study

The purpose of this study was to investigate volume changes in posterior airway space (PAS) after bilateral mandibular advancement surgery. Measurements were taken based on three-dimensional (3D) records available for a large and homogeneous cohort of patients. Pre- and postoperative CBCT scans of 102 adult patients with Class II dysgnathia were visualized and analyzed using 3D software (Mimics® Innovation Suite 14.1; Materialise, Leuven, Belgium). The PAS was divided into three segments by three planes parallel and one plane perpendicular to the Frankfort horizontal plane. Total volume, partial volumes, and cross-sectional areas were calculated from the pre- and postoperative scans. Dahlberg coefficients were obtained to verify each parameter for the measurements' reliability. The statistical significance of the changes observed was analyzed by Wilcoxon's rank-sum test. Highly significant (p=0.000) increases in total posterior airway volume (+32.0%) were noted as an effect of mandibular advancement surgery, amounting to 45.6% in the lower PAS third compared to 38.8% in the middle and 12.5% in the upper PAS third. We also obtained highly significant (p=0.000) increases in all the cross-sectional areas investigated, amounting to 48.5% on the soft-palate level compared to 21.6% on the level of the epiglottis tip, and 14.6% on the hard-palate level. These results demonstrate that bilateral mandibular advancement surgery in Class II-Patients leads to significant increases in PAS volume and significant widening of the narrower sites inside the pharynx.

Different manifestations of Class II Division 2 incisor retroclination: a morphologic study

INTRODUCTION

The aims of this study were to investigate whether there is a different transverse morphologic pattern of dental arches among patients with different manifestations of Class II Division 2 incisor retroclination and to evaluate to what extent the pattern of smaller-than-average teeth in Class II Division 2 malocclusion is common to all groups studied. This information might clarify whether different Class II Division 2 phenotypes represent a single etiology or multiple etiologies.

METHODS

The sample comprised 108 subjects with Class II Division 2 malocclusions, divided into 2 groups according to the type of incisor retroclination: group I included 43 Class II Division 2 subjects with retroclination exclusively of the maxillary central incisors, and group II included 65 Class II Division 2 subjects with retroclination of the 4 maxillary incisors. Maxillary and mandibular intercanine and intermolar widths as well as mesiodistal crown dimensions of the 4 maxillary and mandibular incisors were determined from the patients' initial study models. Mean values of all variables were compared between the 2 groups by sex with analysis of variance.

RESULTS

From the comparison between these 2 groups, no statistically significant differences were found for all transverse measurements (P >0.05). For all mesiodistal measurements analyzed, statistically significant differences between the groups were only found for the mean value of both maxillary lateral incisors' mesiodistal dimensions in both sexes (P <0.05).

CONCLUSIONS

It is not possible to attribute a characteristic pattern of dental arch-width and incisor mesiodistal dimensions to the different manifestations of incisor retroclination in Class II Division 2 malocclusion.

Enhanced increase in pharyngeal airway size in Japanese class II children following a 1-year treatment with an activator appliance

OBJECTIVE

The aim of this study was to assess the upper airway soft-tissue structures in Class IIJapanese children following activator treatment by means of cephalometric analysis.

STUDY DESIGN

A lateral cephalometric radiograph was taken of each patient at Ti (prior to the placement of the activator; mean age: 11 years, 5 months) and T2 (after 1 year of activator treatment; mean age: 12 years, 5 months). Tracings of the lateral cephalometric radiographs were made on acetate paper, and several soft-tissue points and contours of the tongue, soft palate, hyoid, and pharynx were digitised.

RESULTS

The sizes of the oropharynx and hypopharynx were significantly smaller in Class II patients than in Class I patients. Moreover, significant differences were observed in the sizes of the tongue and soft palate between Class I and II patients at the age of 12. In terms of the ratio of change relative to the initial values between the 2 skeletal patterns, the width and dimension of the pharyngeal airway in Class II patients showed considerable increases after activator use.

CONCLUSION

The pharyngeal airway soft tissue structures of Class I patients using the activator exceeded normal growth after 1 year. This finding suggests that correction ofskeletal Class II discrepancies by the activator in orthodontic treatment could reduce the risk of respiratory problems, such as severe snoring, obstructive sleep apnoea, and excessive daytime sleepiness in the future.

Early functional treatment in Class II division 1 subjects with mandibular retrognathia using Fränkel II appliance. A prospective controlled study

AIM

This was to clarify dentoalveolar, skeletal and facial profile modifications induced by Fränkel II functional treatment in Class II division 1 subjects in prepubertal stages CS1-2.

MATERIALS AND METHODS

Evaluation of 25 caucasian subjects (15 males, 10 females), mean age 8y 11m, in vertebral stages CS1-2. The mean duration of functional treatment was 1y 11m.

STUDY DESIGN

Prospective controlled study. The sample was evaluated at T0, start of treatment, and T1, end of Fränkel II therapy. Untreated subjects in Class II division 1 were the control group.

STATISTICS

T-test for paired data was calculated before and after treatment (P< 0.05).

RESULTS

A statistically significant increase between T0 and T1 was obtained for SNB (p = 0.022), ANB (p <0.001), Mx/Mn differential (p = 0.001), Co-Go-Me (p = 0.014), OJ (p < 0.001), OB (p = 0.042), IMPA (p = 0.021) . OJ (p < 0.001) and OB (p = 0.003) showed a higher significant change in the Fränkel group compared to control group.

CONCLUSION

The Fränkel II appliance produced, in CS1-2 subiects, significant effects in teeth position, skeletal modifications and soft tissue changes, although the pubertal growth spurt would occur at least two years later.

Basic dental information needed for the OFM initial occlusal evaluation

It is incumbent upon the orofacial myologist to evaluate the presenting client's occlusion and detect any behaviors which may be influencing the alignment of the dentition or interfering with the treatment plan of the referral source. In order to accomplish these tasks, it is necessary to share some common terminology and to effectively communicate between all the participants involved in the treatment plan. The purpose of this article is to assist in accomplishing these goals.