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

Evaluation of the soft tissue facial profile in different skeletal malocclusions in relation to age

BACKGROUND

The aim of the study was to assess the thickness of the soft tissue facial profile (STFP) in relation to the skeletal malocclusion, age and gender.

METHODS

All patients, aged 7-35 years, who were seeking orthodontic treatment at the Department of Orthodontics, Medical University of Warsaw between 2019 and 22 were included in the study. All patients had lateral head radiographs taken before the treatment. The cephalometric analysis was performed including the STFP analysis. The patients were allocated to one of six groups based on age and skeletal relations (ANB angle). The minimum number of patients in each group was 60 with equal gender distribution. The STFP analysis included ten linear measurements.

RESULTS

A total of 300 patients were included in the study and allocated to five groups. Group 6 (growing patients with skeletal Class III malocclusion) was not included in the study as it failed to achieve the assumed group size. There were significant differences in the thickness of the STFP in relation to the skeletal malocclusions. Adults with skeletal Class III malocclusion had significantly thicker subnasal soft tissues compared to patients with skeletal Class I and Class II malocclusions. The thickness of the lower lip in patients with Class II skeletal malocclusion was significantly bigger compared to the other groups. Children and adolescents with Class II malocclusions had thicker lower lip in comparison to the group with Class I malocclusion. The majority of the STFP measurements were significantly smaller in children and adolescents compared to adults. The thickness of the STFP in males was significantly bigger in all age groups compared to females.

CONCLUSIONS

The thickness of facial soft tissues depends on the patient's age and gender. The degree of compensation of the skeletal malocclusion in the STFP may be a decisive factor during orthodontic treatment planning regarding a surgical approach or a camouflage treatment of skeletal defects.

Comparisons of soft tissue changes after Herbst appliance treatment in three different growth phases

BACKGROUND

This study aimed to compare the soft tissue effects of Herbst appliance in Class II malocclusion patients treated in three different craniofacial growth phases: prepubertal (PRE), circumpubertal (CIR), and postpubertal (POS).

METHODS

In total, 95 patients with Class II Division 1 malocclusion previously treated with a Herbst appliance were analyzed. Through the cervical vertebral maturation stages method, patients were allocated into three groups depending on the growth craniofacial phase at the beginning of treatment: PRE, CIR, and POS. Seventeen cephalometric measures were evaluated from each lateral radiograph before and after Herbst therapy using the Radiocef 2 software (Radio Memory, Belo Horizonte). Intragroup and intergroup treatment changes were compared statistically using a paired t test and MANOVA test, respectively.

RESULTS

Soft tissue thickness changes were related only to mandible; all three mandibular measurements (L1_LL, B_B', and Pog_Pog') showed thickening for the PRE group ranging from 0.92 mm (Pog_Pog') to 2.02 mm (B_B'), and only lower lip thickened overtime for the POS group (L1_LL = 0.99 mm). Soft and hard tissue pogonion displaced anteriorly, but only the soft tissue showed differences among groups; PRE group presented more anterior displacement than POS group (3.61 mm and 1.39 mm, respectively). Hard and soft tissue facial convexity decreased more in the PRE and CIR groups than in the POS group. Mentolabial sulcus depth reduced more in the PRE (1.07 mm) and CIR (1.29 mm) groups than in the POS (0.55 mm) group. Horizontal movement of the skeletal and soft pogonion presented a moderate-high positive correlation (r = 0.783), and hard and soft facial convexity showed a moderate-low positive correlation (r = 0.403).

CONCLUSIONS

Herbst appliance therapy produces soft tissue improvements in the three phases of craniofacial growth, being greater in patients in the PRE and CIR phases.

Facial Soft Tissue Characteristics Among Sagittal and Vertical Skeletal Patterns: A Cone-Beam Computed Tomography Study

Background Facial esthetics depend on the skeletal and dental structures underlying variable facial soft tissue thickness. In this social context, determining the relationship between external soft tissue and underlying skeletal and dental hard tissue is essential for detailed orthodontic diagnosis and treatment planning. Objective This study aims to measure facial soft tissue thickness in different sagittal and vertical skeletal patterns. Methodology This is an observational study utilizing pre-existing cone-beam computed tomography (CBCT) images of 170 subjects (110 females and 60 males) with a mean age group of 37.45 ± 13.83 years. CBCT images were then classified sagittally based on the point A-Nasion-point B (ANB) angle from Steiner's analysis into skeletal Class I, Class II, and Class III. Furthermore, vertical patterns were grouped based on the Frankfort-mandibular plane angle (FMA) from Tweed's analysis into hyperdivergent, hypodivergent, and normodivergent facial types. One-way ANOVA was used to compare the means of facial soft tissue thickness between the skeletal groups, followed by Tukey's post-hoc test for individual comparison. Multinomial logistic regression analysis was used to test the association between gender, age, and skeletal groups. The significance level was 0.05. Results One-way ANOVA revealed statistically significant differences in both sagittal and vertical groups (p≤0.05). Tukey's post hoc analysis showed that the skeletal Class III group has increased soft tissue thickness in the subnasale, upper lip, and mention compared to Class I and Class II subjects. Moreover, the hypodivergent group demonstrated increased soft tissue thickness in gnathion and mentioned landmarks in relation to the other groups. Multinomial logistic regression analysis showed significant differences between groups according to both gender and sagittal skeleton patterns (p≤0.05), with males less likely to be in Class II. Conclusions Skeletal Class III and hypodivergent groups have thicker soft tissue in specific facial landmarks. Sexual dimorphism was marked in soft tissue measurements.

ENHANCING SMILE ESTHETICS IN A PATIENT WITH VERTICAL MAXILLARY EXCESS BY TOTAL MAXILLARY ARCH INTRUSION USING TEMPORARY SKELETAL ANCHORAGE SYSTEM

Smile esthetics is a prime concern in contemporary orthodontic therapy. This case report is about a growing female patient with the inability to close the lips, vertical maxillary excess and hyperdivergent class II skeletal pattern. To enhance skeletal therapy benefits , differential intrusion of segments in the upper arch was required. Bilateral Bollard type miniplates were inserted on the infrazygomatic crest . The technique employed helped this patient avoid orthognathic surgery by allowing a complete upper arch intrusion, treating lip incompetence and causing counterclockwise movement of the mandible.

Profile shape variation and sexual dimorphism amongst middle-aged Northern Europeans

AIM

To explore profile shape variation in a large population of middle-aged individuals and investigate features of sexual dimorphism.

MATERIALS AND METHODS

Facial profile photographs of 1776 individuals (964 females and 812 males; 46 years old), members of the Northern Finland Birth Cohort 1966 (NFBC1966), were uploaded and digitized with Viewbox software. Profile shape was defined with 47 landmarks (4 fixed and 43 sliding semi-landmarks). Digitized images were reoriented and scaled with Procrustes Superimposition, and shape variation was determined with a Principal Component Analysis.

RESULTS

More than 90 per cent of profile shape variation was explained by Principal Components (PC) 1-9. PC1, explaining the largest amount of variation (33.1 per cent) described changes in facial convexity, slope of the forehead, lip, and chin protuberance. PC2 (23.1 per cent variation) was more related to vertical changes of the lower facial third and PC3 (11 per cent variation) primarily described changes in lip protrusion and nasal projection. Shape analysis showed a significant difference between the average female and the average male profile shape (P < 0.001); however, this was not evident upon visual observation. The shape variable most associated with sex was PC3 (η 2 = 0.245; P < 0.001), which described changes in lip prominence and in projection of the dorsal nasal surface. An additional discriminant analysis showed that profile shape predicted sex in 76 per cent of males and 79.6 per cent of females.

CONCLUSIONS

There is significant sexual dimorphism in facial profile among middle-aged adults. Profile shape variation was associated to changes in lip protrusion, nasal protuberance, and chin projection.

Factors affecting changes in soft tissue profile after various treatment modalities for skeletal Class II malocclusion: A cross-sectional study

INTRODUCTION

Various treatment modalities are used to treat skeletal Class II malocclusion with different effects on the soft tissue. This study was aimed to determine factors affecting changes in soft tissue profile after various treatment modalities for skeletal Class II malocclusion.

MATERIALS AND METHODS

A cross-sectional study was conducted using pre-treatment and post-treatment lateral cephalograms of 141 subjects. The sample consisted of 47 patients treated with Clark's Twin Block, 47 with first premolar extractions, and 47 with Class II elastics. The post-treatment cephalograms were superimposed on pre-treatment radiographs using stable landmarks: anterior wall of sella turcica and anterior cranial base. The changes in profile were evaluated by paired t-test using X-Y co-ordinate system. Changes in profile were predicted by using multi-variable linear regression analysis. Level of significance was kept at P≤0.05.

RESULTS

The changes in soft tissue profile were statistically significant for all the landmarks (P<0.001) of nose, upper and lower lip, and chin in horizontal and vertical direction, except subnasale and labrale superius in the horizontal direction. The soft tissue profile changes can be predicted for all landmarks with various prediction powers except pronasale, subnasale, and inferior labial sulcus in the vertical direction.

CONCLUSIONS

Almost all the soft tissue landmarks of nose and lower third of the face exhibit downward and forward movement. The changes in the upper lip in both horizontal and vertical directions were found to be more predictable than those occurring in the lower lip.

Differences in Angular Photogrammetric Soft-Tissue Facial Characteristics among Parents and Their Offspring

Background and objectives: The objective of this study was to determine if the angular photogrammetric analysis of soft-tissue characteristics can determine similarities between parents and their offspring in the Serbian population. Materials and Methods: A total of 15 families (52 participants) met the participation criteria of this study and their facial profile images were analyzed using the ImageJ software. Subjects were divided into groups of mothers and fathers and four groups of children (divided according to their age and gender). In total, twelve angular measurements were made on the standardized digital images of the profiles of the participants and the obtained data were compared using one-way ANOVA. Results: The obtained results showed that there were statistically significant differences in the values of the nasal and cervicomental angles, as well as the angle of the total facial convexity, between the group of fathers, on one side, and groups of male/female children, on the other. Conclusions: This work represents the first photogrammetric analysis of facial soft-tissue characteristics of children and adults in the Serbian population. The data suggest that there are much more similarities between the facial soft-tissue angles of fathers and their male offspring. Furthermore, mothers tend to have statistically insignificant differences in angle sizes, compared to both male and female offspring.

Correlation between vertical components and skeletal Class II malocclusion in ethnic Javanese

Introduction

The dentoskeletal morphology of Class II malocclusion has been analyzed in several cephalometric investigations. It is crucially important to understand the vertical components in orthodontic treatment. Defining the facial type of an individual is an essential key to obtain an accurate orthodontic diagnosis.

Aim

The aim of this study was to understand the correlation of vertical components in Class II skeletal malocclusion.

Materials and methods

This is a observational descriptive study. This study used lateral cephalograms of Class II skeletal malocclusion from Universitas Airlangga Dental Hospital, between April 2015 and 2016. Cephalometric analysis was performed using digital software by a single examiner. This analysis measured gonial (Go), upper gonial (Go₁), lower gonial (Go₂), Yaxis-SN angle, the length of anterior face height, and posterior face height. The correlation between each variable was analyzed using the Pearson correlation test (P<0.01).

Results

There was a correlation between vertical components and Class II skeletal malocclusion.

Conclusion

Vertical components were correlated with Class II skeletal malocclusion. The greater ANB angle will be followed by greater Go₂, which worsens the condition of Class II skeletal malocclusion.

Morphological differences in lower facial third soft tissues in children with and without gingival smile: A cross-sectional comparative study

AIM

The aim of the present study was to establish the relationship between lower facial third and smile type in silent mixed-dentition patients.

METHODS

This cross-sectional study, approved by the ethics committee, was conducted in a population of 2760 children, from which a convenient sample of 198 was included: 75 with gingival smile (GS) and 123 without GS (1:1.64). Clinical examination and videos were taken. Occlusal relation, overjet (OJ), overbite (OB), superior lip length at rest, superior lip length while smiling (SLLS), lower facial third height (LFTH), mid-facial third height (MFTH), clinical crown length, and lip lift ability (LLA) were measured by two calibrated examiners (intraclass correlation coefficient: ≥.95). A normality test and demographic and bivariate analyses were undertaken. A non-paired Student's t test was carried out in order to observe statistically-significant differences between variables.

RESULTS

There were no differences between sexes or associations between LFTH and GS. Statistically-significant differences (P < .05) in MFTH, SLLS, LLA, OJ, and OB were found. A logistic regression model showed that the sum of LLA (odds ratio [OR]: .65, 95% confidence intervals [CI]: .50,.83]) and OB (OR: .88, 95% CI: .82, .93]) were GS predictive factors in 81.3% of cases.

CONCLUSIONS

OB and LLA are GS predictive factors in prepubertal participants. There is no relation between LFTH and GS.

[Does gender make a difference in orthodontics? A literature review]

OBJECTIVES

The objective of this literature review is to investigate whether the gender of patients and practitioners makes any difference to orthodontic treatment.

MATERIALS AND METHODS

Sixty-nine articles were selected, the vast majority of which studied patient gender.

RESULTS

Young females are the category of patients which most often apply for orthodontic treatment, probably because of their higher aesthetic demands, despite their objective needs being no greater. Aesthetic, skeletal and dental analyses reveal an obvious dimorphism with larger dimensions in males, especially for the nose, cheekbones, mouth and mandibular canines. Nevertheless, cephalometric angular values do not vary significantly between male and female individuals. Growth is quantitatively greater in males. It also occurs later, as does eruption and maturation of their teeth. Response to the different orthodontic / orthopedic therapies would appear not to differ according to the sex of the patient.

DISCUSSION

These results, however, need to be qualified according to the country concerned, the patients' life style and mind frames, as these can modify or influence the studied parameters.

Cross-sectional human study of soft tissue chin (STC) thickness in adult patients in relation to sex, facial pattern and skeletal class

PURPOSE

The aim of this study was to study the relations between the soft tissue chin (STC) and sex, skeletal class, and facial pattern; and to describe the shape and behavior of the STC.

METHODS

385 non-growing patients were selected, 206 women and 179 men, with a mean age of 28.8 years (SD 4.2). Patients were divided into groups by skeletal class (class I, II or III) and facial pattern (brachyfacial, mesofacial or dolichofacial). STC thicknesses were measured at pogonion (Pg), soft pogonion (Pg'), gnathion (Gn), soft gnathion (Gn'), menton (Me) and soft menton (Me') in the CBCTs.

RESULTS

Sexual dimorphism was observed at Pg-Pg' and Me-Me'. STC thickness was not related to skeletal class but related to facial pattern. Pg-Pg' and Me-Me' measurements showed significant differences to the combination of skeletal class/facial pattern. STC thickness was not homogenous in terms of shape and behavior.

CONCLUSIONS

The results provide evidence of a strong but complex relationship between sex, facial pattern, skeletal class and STC thickness; for this reason, each patient must be evaluated individually before undergoing orthodontics or orthognathic surgery involving the mandible and the mandibular symphysis.

Factors influencing soft tissue profile changes following orthodontic treatment in patients with Class II Division 1 malocclusion

Background

Several studies have shown soft tissue profile changes after orthodontic treatment in Class II Division 1 patients. However, a few studies have described factors influencing the soft tissue changes. The purpose of this study was to investigate the factors influencing the soft tissue profile changes following orthodontic treatment in Class II Division 1 patients.

Methods

The subjects comprised 104 Thai patients age 8–16 years who presented Class II Division 1 malocclusions and were treated with different orthodontic modalities comprising cervical headgear, Class II traction and extraction of the four first premolars. The profile changes were evaluated from the lateral cephalograms before and after treatment by means of the X-Y coordinate system. Significant soft tissue profile changes were evaluated by paired t test at a 0.05 significance level. The correlations among significant soft tissue changes and independent variables comprising treatment modality, age, sex, pretreatment skeletal, dental and soft tissue morphology were evaluated by stepwise multiple regression analysis at a 0.05 significance level.

Results

The multiple regression analysis indicated that different treatment modalities, age, sex, pretreatment skeletal, dental and soft tissue morphology were related to the profile changes. The predictive power of these variables on the soft tissue profile changes ranged from 9.9 to 40.3 %.

Conclusions

Prediction of the soft tissue profile changes following treatment of Class II Division 1 malocclusion from initial patient morphology, age, sex and types of treatment was complicated and required several variables to explain their variations. Upper lip change in horizontal direction could be found only at the stomion superius and was less predictable than those of the lower lip. Variations in upper lip retraction at the stomion superius were explained by types of treatment (R² = 0.099), whereas protrusion of the lower lip at the labrale inferius was correlated with initial inclination of the lower incisor (L1 to NB), jaw relation (ANB angle), lower lip thickness and sex (R² = 0.403). Prediction of chin protrusion at the soft tissue pogonion was also low predictable (R² = 0.190) depending upon sex, age and initial mandibular plane angle (SN-GoGn). Additionally, age and sex also had mainly effect on change of the soft tissue profile in the vertical direction.

Alveolar and Skeletal Chin Dimensions Associated with Lower Facial Height Among Different Divergent Patterns

INTRODUCTION

Alveolar and skeletal chin dimensions with facial height have an impact on diagnosis and treatment planning in orthodontic patients and serves as a reference landmark for facial aesthetics.

AIM

To evaluate the alveolar and skeleton chin dimensions among different divergent patterns, to evaluate the lower face height in different divergent growth patterns, to give an estimate to the oral surgeon for any adjunctive procedure.

MATERIALS AND METHODS

The study includes a total sample of 45 non-growing individuals (26 males and 19 females) from the archival records of the Orthodontic Department with age ranging between 18-25 years, classified into different divergent patterns based on the mandibular plane angle. The sample was divided into three groups, of which 15 patients in each group were evaluated: Group-1: Normodivergent, Group-2: Hypodivergent and Group-3: Hyperdivergent patterns respectively. Standardized digital lateral cephalograms and antero-posterior cephalograms of these patients were obtained in Natural Head Position (NHP).

RESULTS

The results of the retrospective cephalometeric study were statistically analyzed by using ANOVA and Tukey's multiple post hoc test which showed that hard tissue chin measurement were greater in hypodivergent group (13.7mm) and the increased lower facial height showed statistically significant difference in high mandibular plane angle group (59.6mm). In antero-posterior cephalograms the transverse width showed statistically significant difference in normodivergent group (32.60mm).

CONCLUSION

The anterio-posterior width of the symphysis was higher in hypodivergent growth pattern, whereas vertical height of the symphysis was greater in hyperdivergent group. The lower facial height among three groups showed statistically significant difference among hyperdivergent group. In comparison of all the three groups in Anterio-Posterior (AP) cephalograms, statistically significant difference was noted in normodivergent group when compared with the other two groups.

Perioral soft tissue evaluation of skeletal Class II Division 1: A lateral cephalometric study

INTRODUCTION

To obtain the balance and harmony of the soft tissue facial profile in orthodontic treatment, it is necessary to identify the characteristics of overlying soft tissues according to the horizontal and vertical skeletal patterns. The aim of this study was to evaluate the perioral soft tissue characteristics of skeletal Class II Division 1 subjects (group II) with various vertical patterns compared with skeletal Class I subjects (group I).

METHODS

Lateral cephalograms of 99 Korean adults (44 women, 45 men; mean age, 23.4 years) were divided into 4 groups based on horizontal and vertical skeletal pattern (SN-MP angle): group I, 22 subjects; group II-low angle (<27°), 14 subjects; group II-normal angle (27°-36°), 33 subjects; and group II-high angle (>37°), 30 subjects. The correlations and multiple linear regression tests were used to determine the skeletal and dental variables influencing soft tissue characteristics.

RESULTS

Group II-high angle showed significantly greater values than did group II-low angle for basic lower lip thickness and lower lip length. The perioral soft tissue measurements of group II were correlated with the inclination and anteroposterior position of the maxillary and mandibular incisors along with facial depth (N-Go) and facial length (S-Gn). Upper lip strain of group II was not influenced by any skeletal variables but only by the inclination and anteroposterior position of the maxillary incisors.

CONCLUSIONS

Clinicians need to evaluate lip strain and lip thickness based on the skeletal pattern as well as dental inclination to obtain balance in the perioral muscle activity.

Comparisons of soft tissue chin thickness in adult patients with various mandibular divergence patterns

OBJECTIVE

To evaluate the association between soft tissue at the chin (STC) thickness and mandibular divergence.

MATERIALS AND METHODS

Nongrowing patients seeking orthodontic treatment (n  =  190; 113 women and 77 men), who had an average age of 26.94 years (range  =  18.10-53.50 years), were stratified in four subgroups based on cephalometric mandibular plane inclination to anterior cranial base (MP/SN): low  =  MP/SN ≤ 27° (n  =  48); medium-low  =  27° < MP/SN ≤ 32° (n  =  60); medium-high  =  32° < MP/SN < 37° (n  =  37); and high  =  MP/SN ≥ 37° (n  =  45). The STC thicknesses were measured at pogonion (Pog), gnathion (Gn), and menton (Me). Group differences were evaluated with two-way analysis of variance and Student's t-test. The Pearson product moment correlation gauged associations between parameters.

RESULTS

The STC values were greater in men than women (P < .02) and were smaller in the high group (7.47 ± 2.42 mm) than in all other groups at Gn (mean values  =  9.00 mm < STC < 9.58 mm; P < .001) and at Me (high group  =  6.30 ± 1.89 mm; other groups  =  7.15 mm < STC< 7.57 mm; P  =  .011).

CONCLUSION

The STC is thinner at Gn and Me in hyperdivergent facial patterns, apparently in contrast to Pog. This differential thickness warrants focused research as it implies that it is possible (1) to vertically grow hard tissues impinging on the inferior soft tissue envelope in patients with severe hyperdivergence and (2) to plan for genioplasty in such patients when more advancement of the chin might be needed to compensate for the increased vertical height.

Modificações no pogônio e no nariz de acordo com o modo respiratório

INTRODUÇÃO: o perfil mole do indivíduo é resultado de mudanças complexas que ocorrem nos tecidos duros e moles das estruturas faciais. O pogônio e o nariz são estruturas dominantes na face e influenciam no grau de convexidade do perfil. Assim, é fundamental a análise das estruturas do pogônio e a inclusão das estruturas nasais no plano de tratamento ortodôntico. OBJETIVO: avaliar longitudinalmente as modificações dimensionais no plano anteroposterior do pogônio e do nariz de indivíduos com má oclusão de Classe II, divisão 1 de Angle, em dois momentos distintos do desenvolvimento craniofacial. MÉTODOS: foram realizados traçados cefalométricos sobre telerradiografias em norma lateral de 40 indivíduos, sendo 23 respiradores predominantemente nasais (RN) e 17 predominantemente bucais (RB). RESULTADOS: foram obtidas as medidas lineares e angulares LS'-Pog', LS'-B', B'-Pog', Pog'-PogTeg', Linha NB, Pog-NB, N'-Prn, Prn-NPog, N-Prn-Sn e Prn-Sn-LS. O teste ANOVA a dois critérios com medidas repetidas foi aplicado para indicar diferenças entre os valores médios dessas variáveis segundo os momentos e/ou modo respiratório. Observou-se que as variáveis LS'-B', Pog'-PogTeg', Linha NB e Pog-NB, N'-Prn, Prn-NPog, N-Prn-Sn e Prn-Sn-LS apresentaram diferença significativa (p<0,05) quando comparados os momentos final e inicial, embora não houvesse diferença significativa entre os modos respiratórios. Em nenhuma das variáveis se observou interação entre o modo respiratório e os momentos. CONCLUSÃO: há alteração estatisticamente significativa do pogônio e do nariz no plano anteroposterior no decorrer do crescimento, porém sem qualquer interferência do modo respiratório.

Class II malocclusion occlusal severity description

Objectives

It is well known that the efficacy and the efficiency of a Class II malocclusion treatment are aspects closely related to the severity of the dental anteroposterior discrepancy. Even though, sample selection based on cephalometric variables without considering the severity of the occlusal anteroposterior discrepancy is still common in current papers. In some of them, when occlusal parameters are chosen, the severity is often neglected. The purpose of this study is to verify the importance given to the classification of Class II malocclusion, based on the criteria used for sample selection in a great number of papers published in the orthodontic journal with the highest impact factor.

Material and Methods

A search was performed in PubMed database for full-text research papers referencing Class II malocclusion in the history of the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO).

Results

A total of 359 papers were retrieved, among which only 72 (20.06%) papers described the occlusal severity of the Class II malocclusion sample. In the other 287 (79.94%) papers that did not specify the anteroposterior discrepancy severity, description was considered to be crucial in 159 (55.40%) of them.

Conclusions

Omission in describing the occlusal severity demands a cautious interpretation of 44.29% of the papers retrieved in this study.

Natural changes of the maxillary first molars in adolescents with skeletal Class II malocclusion

INTRODUCTION

The objective of this study was to evaluate natural changes in maxillary posterior alveolar height (MPAH) and axial inclination of the maxillary first molars (AIMFM) in subjects with Class II malocclusion to determine the validity of predictive equations.

METHODS

Longitudinal records of 30 untreated white subjects (13 girls, 17 boys) with skeletal Class II malocclusion were collected at ages 9, 12, 14, and 16 years. They had participated in the Burlington Growth Centre study, and cephalograms were analyzed with Dentofacial Planner Plus software (version 2.0, Dentofacial Planner, Toronto, Ontario, Canada). Serial means were compared with the Bonferroni post-hoc test (P <0.05). Predictive equations were obtained and studied with the analysis of agreement.

RESULTS

Gradually, means of MPAH had statistical increments with sexual dimorphism from 14 to 16 years of age. A distal mean of AIMFM was found at 9 years of age that decreased significantly during growth, with sexual dimorphism between the ages of 9 and 12 years. Changes in AIMFM varied among subjects in distinct stages. Values of MPAH were predicted with high validity at intervals of 3 years or longer, whereas estimations for AIMFM were unreliable.

CONCLUSIONS

In this study group, there was significant alveolar growth, with a natural tendency to upright the distal inclination at the maxillary first molars.

Comparação das dimensões de tecido mole entre padrões faciais distintos

OBJETIVO: o presente estudo destinou-se a comparar a morfologia tegumentar de indivíduos segundo a tipologia facial. MÉTODOS: foram utilizadas 90 telerradiografias de pacientes de ambos os sexos, de 12 a 16 anos de idade, divididas em três grupos distintos, referentes a cada padrão morfológico: mesofacial, dolicofacial e braquifacial. Os grupos foram comparados no que se refere às medidas de espessura e altura do lábio superior e inferior, além da espessura do mento mole. Ainda, foi apurada a presença de correlações entre as variáveis de tecido mole avaliadas e medidas cefalométricas de natureza dentária e esquelética. RESULTADOS E CONCLUSÕES: os lábios superiores e inferiores, assim como o mento mole, não apresentaram diferenças em relação às suas espessuras em todos os grupos morfológicos. Porém, as alturas do lábio superior e inferior foram significativamente maiores para os dolicofaciais quando esses foram comparados aos demais grupos. Braquifaciais apresentaram menor altura do lábio superior quando comparados aos mesofaciais, embora ambos não tenham se diferenciado significativamente no que se refere à altura do lábio inferior. A análise das correlações estabelecidas entre as variáveis dos tecidos moles e duros indicou evidências de um desenvolvimento vertical dos lábios superior e inferior em acompanhamento ao desenvolvimento vertical do esqueleto. O posicionamento vertical do incisivo superior se correlacionou significativamente aos mesmos parâmetros labiais, o que garantiu um nível de exposição semelhante desse elemento dentário em todos os grupos.