Facial Type Research Articles

Perceptions of orthodontists, laypersons, and patients regarding buccal corridors and facial types

The space on each side of the mouth, between the commissure of the mouth and the buccal surface of the last visible tooth, is called the buccal corridor. The size of the buccal corridor can affect perceptions of facial esthetics. We analyzed the perceptions of orthodontists, laypersons, and orthodontic patients regarding the size of buccal corridors in people with brachyfacial, mesofacial, and dolichofacial types. Photographs of 1 male and 1 female model were modified digitally into brachyfacial, mesofacial, and dolichofacial types. Each facial type was further modified to create 5 sizes of buccal corridors. Orthodontists, adult orthodontic patients, and laypersons were invited to rate the photographs. Orthodontists rated lower than the other groups of raters when they evaluated the female model with the buccal corridors of 20% (P<0.05). Laypersons could not distinguish the changes of the buccal corridors when evaluating the male model with brachyfacial and mesofacial (P>0.05). Orthodontic patients rated significantly higher than the orthodontists and the laypersons when evaluating the dolichofacial type of both models (P<0.05). Orthodontists are more sensitive to the buccal corridors than are orthodontic patients and laypersons. It is only necessary to consider eliminating the patient's buccal corridors when the buccal corridor area ratio is over 15%.

The influence of facial types on the morphology and location of the greater palatine foramen: a CBCT study.

This study aimed to assess the morphology and location of the great palatine foramen (GPF) of different facial types using cone beam computed tomography (CBCT) scans. Sixty CBCT scans were divided into: brachyfacial (n = 20), dolichofacial (n = 20) and mesofacial (n = 20) using Ricketts' VERT index for the determination of cephalometric facial type and imported into ImageJ software. GPF shape was characterized as: round, elongated in the anteroposterior direction (EAP), or elongated in the latero-medial direction (ELM). The distances between the GPF and the palatine suture (PS), the center of the GPF and the center incisive foramen (IF), the GPF and the palatine alveolar ridge (PAR), right side GPF (GPFr) and left side (GPFl) GPFs; and the angles formed from the intersection of the GPF, IF and PS were assessed. The position of the GPF was evaluated in relation to the molars. GPFr and GPFl mean distances from PAR presented higher values for dolichofacial patients (p < 0.05). GPFr and GPFl location distally to the third molar (3M) was higher for brachyfacial type, while their location distally to the second molar was higher for mesofacial and between the mesial and distal surfaces of the 3M for dolichofacial (p < 0.05). The GPF was more distant from the PAR in the dolichofacial-type group. The location of the GPF in relation to the molars varied according to the facial type. However, the morphology of the GPF was similar in the three facial types, and the elongated in the anteroposterior direction morphology was more frequent.

Do the location and dimensions of the mental foramen differ among individuals of different facial types and skeletal classes? A CBCT study

Statement of problemKnowledge about the location and dimensions of the mental foramen is important for surgical planning and implant placement in the posterior mandibular region. PurposeThe purpose of this clinical study was to assess the location and dimensions of the mental foramen in individuals of different facial type, skeletal class, and sex by means of cone beam computed tomography (CBCT) images. Material and methodsCBCT images of 142 individuals (72 women and 70 men) were classified according to the facial type (dolichocephalic, mesocephalic, or brachycephalic) and skeletal class (I, II, or III). The vertical and horizontal locations of each mental foramen were evaluated on panoramic reconstructions, and the greatest height and width of the mental foramen were determined on multiplanar reconstructions. Also, the distances from the mental foramen to the alveolar crest and to the inferior cortex of the mandible were obtained. The data were compared by using the Kruskal-Wallis test and multiway analysis of variance (α=.05). ResultsThe facial type, skeletal class, and sex did not influence the vertical (P=1.00) or the horizontal (P>.15) location of the mental foramen. The most frequent location of the mental foramen was between the first and second premolars and below their apices. The dimensions of the mental foramen were not influenced by the studied factors in men (P>.07); conversely, the mental foramen dimensions were influenced for women (P<.03). ConclusionsThe most frequent location of the mental foramen was between the first and second premolars and below their apices. An influence of the facial type and skeletal class was observed on the dimensions of the mental foramen in women.

Safe sites for orthodontic miniscrew insertion in the infrazygomatic crest area in different facial types: A tomographic study

Temporary skeletal anchorage devices (TSADs) are used to obtain skeletal anchorage for orthodontic treatment. Their insertion in the infrazygomatic crest (IZC) allows efficient orthodontic mechanics. Different facial types have different bone configurations. We aimed to evaluate the differences in bone thicknesses in the IZC area among patients of each facial type to determine a safe zone for TSAD insertion.For this retrospective study, 86 cone-beam computed tomography (CBCT) scans were divided into 3 groups according to the facial type: group I, 24 CBCT scans of hyperdivergent patients; group II, 30 scans of neutral patients; and group III, 32 scans of hypodivergent patients. The buccal alveolar bone thickness was measured in 6 zones between the second premolar and distal root of the second molar, 5, 7, 9, and 11 mm apical to the alveolar crest.The IZC areas with minimum thickness for TSAD insertion follows: group I, between first and second molars at 11 mm from the alveolar crest, mesial root of the second molar at 9 mm from the crest, and distal root of the second molar at 11 mm from the crest; groups II and III, between first and second molars at 11 mm from the crest and mesial root of the second molar at 11 mm from the crest.The safe zones for IZC miniscrew insertion are located 11 mm from the alveolar crest between the maxillary first and second molars and on the mesial root of the second molar for all the 3 facial types.

Do the dimensions of the hard palate have a relationship with the volumes of the upper airways and maxillary sinuses? A CBCT study

BackgroundAs the hard palate is a central structure of the skull, and its close relationship with the nasal cavity, oral cavity, and maxillary sinuses, it would be of interest to study if there is a relationship between this bone and other structures of the stomatognathic system. Thus, this study aimed to assess the dimensions of the hard palate and associate them with sex, and skeletal and breathing patterns. Also, to investigate if there is a relationship between these dimensions and the volumes of the upper airways and maxillary sinuses.MethodsTwo hundred and ninety-eight CBCT scans of patients were classified according to sex, and skeletal and breathing patterns. Then, the linear dimensions of width and height of the hard palate at the regions of the first premolars and first molars, and the volumes of the upper airways and maxillary sinuses were measured using the CS 3D Imaging and ITK-SNAP software, respectively. Data were submitted to multi-way analysis of variance and linear regression, with a significance level of 5% (α = 0.05).ResultsSex and facial type influenced the hard palate dimensions (p < 0.05). Males had greater width and height of the hard palate than females (p < 0.0001). It was observed greater width for brachycephalics at the first premolars region (p = 0.0032), and greater height for dolichocephalics at the first premolars (p = 0.0154) and first molars (p = 0.0038) regions. Skeletal malocclusion and breathing pattern did not influence the measurements of the hard palate (p > 0.05). There was a significant relationship between the width and height of the hard palate at the premolar’s region and the total volume of the upper airways (p = 0.018, and p = 0.038), and between both dimensions of the hard palate at the molar’s region and the total volume of the maxillary sinuses (p < 0.0001).ConclusionsThe hard palate dimensions are influenced by sex and facial type, but not by skeletal malocclusion or breathing pattern. Also, there is an association between these dimensions and the volumes of the upper airways and maxillary sinuses.

Does Maxillary Sinus have any Influence on the Skeletal Class or Facial Type?

Does Maxillary Sinus have any Influence on the Skeletal Class or Facial Type?

Class II division 1 malocclusion treatment with extraction of maxillary first permanent molars: cephalometric evaluation of treatment and post-treatment changes

Abstract Objective To investigate the cephalometric outcome and post-treatment changes following the orthodontic treatment involving the extraction of maxillary first molars in patients presenting with a Class II division 1 malocclusion. Methods A retrospective longitudinal study was conducted involving 83 patients treated by fixed appliances and the extraction of 16 and 26. The mean age at commencement was 13.2 ± 1.5 years. Lateral cephalograms were available pre-treatment (T1), immediately post-treatment (T2), and at 2.6 years post-treatment (T3). The sample was divided into hypodivergent (n = 18), normodivergent (n = 17), and hyperdivergent (n = 48) facial types. Mean increments, standard deviations, and 95% confidence intervals were calculated for T2–T1 and T3–T2. Increments were tested using paired-samples t-tests, and variables between groups by applying ANOVA followed by Tukey’s post hoc test. Linear regression was used to examine the effect of facial type, age, and gender. Results Significant changes occurred during treatment for most cephalometric variables. Post-treatment, the growth pattern showed a tendency to return to the original form. Facial type had only a minor influence on cephalometric increments during and after treatment. Conclusions Post-treatment skeletal, soft tissue, and dentoalveolar changes were limited. Facial type had only a minor influence during and after treatment and care must be taken to control lower incisor inclination.

Aesthetic Unit-Based Reconstruction of Facial Defects with Local Flaps after Surgical Excision of Basal Cell Carcinoma

Background: Basal cell carcinoma (BCC) represents themost common type of facial skin cancer in Middle East andEgypt. It rarely metastasizes, but because of its locally destructivenature, it can cause high morbidity. Reconstructionby local flap after surgical excision depends on the size ofthe defect and the affected facial aesthetic unit.Aim: To reveal the prevalence of facial BCC, relation ofits site to facial aesthetic units and type of local flaps usedfor reconstruction per units.Patients and Methods: A retrospective study was conductedon 80 patients with facial BCC that admitted to the outpatientclinic, Plastic Surgery Department, Qena University Hospitalfrom June 2018 to May 2020 (2 years duration). Only earlystageand primary tumors were included. Statistical analysis:Data was analyzed using the Statistical Package for SocialSciences (SPSS) version 24. A p-value significant.Results: 80 patients with facial basal cell carcinoma (BCC)were collected from medical records. 45 (56.25%) patientswere males and 35 (43.75%) patients were females (M:F =1.3:1). Ages ranged from 52-78 years old (SD = 65±13).Nodular subtype was the most common clinical type of BCCand presented in 45 (56.25%) patients. Nasal unit was themost common site in 18 (22.5%) patients. The most randomflap applied was the rhomboid (Limberg) flap in 15 cases.The most axial flap used was the nasolabial flap in 9 cases.Complications (6 cases, 7.5%) included: Wound dehiscencein 3 cases, infection in 2 cases and skin slough in 1 case. TheSCAR scale score result ranged from 0-2 score.Conclusion: Facial defects reconstruction after surgeryfor basal cell carcinoma is a complex endeavor that requirescareful consideration. There are many different local flapsavailable depending on the particular facial subunit thatrequires reconstruction. Careful recognition of the principlesof the facial subunits will equip the surgeon to achieve thebest possible functional and aesthetic outcomes.

Regression models of teleroentgenograhic indicators of the position of teeth and the profile of face soft tissues in juvenile aged persons with different face types according to Schwarz A.M.

Considering the differences in the values of teleroentgenograhic (TRG) indicators in different racial, gender, ethnic, age, population, geographical population groups and numerical methods of TRG analysis, determination of normative values of cephalometric, gnatometric TRG-indicators, their interdependencies in the population of different countries is extremely important both for human anatomy and for the practice of dentists. This fully applies to residents of Ukraine of different age groups. The aim of the work is to develop and analyze regression models of teleroentgenograhic indicators of tooth position and facial soft tissue profile according to Schwarz A.M. in Ukrainian young men and young women with different facial types. Lateral teleroentgenograms of 49 young men (aged 17 to 21 years) and 76 young women (aged 16 to 20 years) with physiological occlusion as close as possible to orthognathic were analyzed. In the license package “Statistica 6.0” regression models of indicators of position of teeth and profile of soft tissues of the face according to the method of Schwarz A.M. depending on basic cephalometric and gnatometric indicators separately for boys and for girls with different types of the face are constructed. In young men, 16 of the 24 possible reliable regression models were constructed, in which the coefficient of determination is greater than 0.6 (R2=from 0.609 to 0.998). For young men with 1st (back face type) and 3rd (front face type) face types, the following models were created with respect to 5 indicators from 8 possible (respectively, angles Max1-SpP S-arz, distances Sn-Pn and Pog’-Por, angles Gl’LsPog’ and SnPog’-Pn; R2 = from 0.609 to 0.998 and angles Max1-SpP S-arz and Mand1-MP Schwars, distances Sn-Pn and Pog’-Por, angle Gl’LsPog’; R2 = from 0.609 to 0.946), and for young men with 2nd face types (average face type according to Schwarz AM) – for 6 indicators (angles Max1-SpP S-arz and Mand1-MP Schwars, distances Sn-Pn and Pog’-Por, angles Gl’LsPog’and SnPog’-Pn; R2 = from 0.690 to 0.990). In young women, 17 of the 24 possible reliable models with R2 greater than 0.6 (R2 = 0.628 to 0.958) were constructed. For young women with 1st type of face 6 indicators are modeled – angles Max1-SpP S-arz, distances Sn-Pn and Pog’-Por, angles Gl’LsPog’and SnPog’-Pn, the distance of Li-SnPog’(R2= from 0.663 to 0.958). For young women with 2nd face type, the following models were created for 7 indicators – angles Max1-SpP S-arz and Mand1-MP Schwars, distances Sn-Pn and Pog’-Por, angles Gl’LsPog’ and SnPog’-Pn, distances Li-SnPog’(R2= from 0.628 to 0.891). For young women with 3rd face type the smallest number of models with R2 larger than 0.6 was built, compared to all groups of persons with different face types – only 4 models for Max1-SpP S-arz angle, Pog’-Por distance, angles Gl’LsPog’ and SnPog’-Pn (R2 from 0.718 to 0.847).

Geometric morphometric analysis of growth patterns among facial types

Introduction:Extreme patterns of vertical facial divergence are of great importance to clinicians because of their association with dental malocclusion and functional problems of the orofacial complex. Understanding the growth patterns associated with vertical facial divergence is critical for clinicians to provide optimal treatment. This study evaluates and compares growth patterns from childhood to adulthood among 3 classifications of vertical facial divergence using longitudinal, lateral cephalograms from the Craniofacial Growth Consortium Study.Methods:Participants (183 females, 188 males) were classified into 1 of 3 facial types on the basis of their adult mandibular plane angle (MPA): hyperdivergent (MPA >39°; n = 40), normodivergent (28° ≤ MPA ≤ 39°; n = 216), and hypodivergent (MPA <28°; n = 115). Each individual had 5 cephalograms between ages 6 and 20 years. A set of 36 cephalometric landmarks were digitized on each cephalogram. Landmark configurations were superimposed to align 5 homologous landmarks of the anterior cranial base and scaled to unit centroid size. Growth trajectories were calculated using multivariate regression for each facial type and sex combination.Results:Divergent growth trajectories were identified among facial types, finding more similarities in normodivergent and hypodivergent growth patterns than either share with the hyperdivergent group. Through the use of geometric morphometric methods, new patterns of facial growth related to vertical facial divergence were identified. Hyperdivergent growth exhibits a downward rotation of the maxillomandibular complex relative to the anterior cranial base, in addition to the increased relative growth of the lower anterior face. Conversely, normodivergent and hypodivergent groups exhibit stable positioning of the maxilla relative to the anterior cranial base, with the forward rotation of the mandible. Furthermore, the hyperdivergent maxilla and mandible become relatively shorter and posteriorly positioned with age compared with the other groups.Conclusions:This study demonstrates how hyperdivergent growth, particularly restricted growth and positioning of the maxilla, results in a higher potential risk for Class II malocclusion. Future work will investigate growth patterns within each classification of facial divergence.

Regression models of individual teleradiographic indicators according to Ricketts method in Ukrainian young men and young women with different face types

Annotation. Anomalies of the dental-jaw system are one of the most difficult challenges of modern orthodontics, and accordingly require the use of modern and evidence-based therapy. To predict the results of treatment and proper planning of orthodontic interventions, a reliable tool in the hands of an orthodontist is cephalometric analysis by the Ricketts method. An important step in the successful implementation of this method of analysis is to conduct a study taking into account ethnicity, age, sex and the influence of facial type on teleradiographic indicators calculated by this method. The aim of the study is to build and analyze regression models of teleradiographic indicators used in the Ricketts method for Ukrainian young men and young women with orthognathic occlusion with different face types. Ricketts teleradiography was performed for 49 young men and 76 young women with orthognathic occlusion. Cephalometric analysis was performed using OnyxCeph³™ software, 3DPro version, Image Instruments GmbH, Germany (software license URSQ-1799). The division into facial types was performed by determining the morphological index of Garson. All indicators were divided into three groups: the first group included the main cephalometric points and measurements used in modern cephalometric analyzes Schwartz, Ricketts, Steiner, Roth-Jarabak, Burstone and Bjork and are parameters that usually do not change during surgery and orthodontic treatment; to the second group – metric dental-jaw characteristics by the Ricketts method by which surgical methods can change the length, width, angles and position of the jaws; to the third group – indicators according to the Ricketts method which characterize the position of each individual tooth relative to each other, cranial structures and the profile of the soft tissues of the face. Regression models of individual teleradiographic indicators are built using the license package "Statistica 6.0". Only reliable models with a coefficient of determination higher than 0.6 were subject to analysis. Of the 13 possible facial features, 9 models of teleradiographic indicators (R² = from 0.691 to 0.834) were included to the second group, depending on the indicators of the first group, and 9 (R² = from 0.640 to 0.910) of the 15 possible models of indicators were included to the third group depending on the indicators of the first and second groups. In young men with a wide type of face, the constructed models of indicators included to the second group, depending on the indicators of the first group, most often include the distance Ar-Go (20.7 %), angle POr-NBa (13.8 %), distances N-S and S-E and the ratio N-S:S-Ar' (10.3 % each); and to the models of indicators included in the third group depending on the indicators of the first and second groups – the angle N-CF-A (12.8 %), the distance Ar-Go (10.3 %), the distances N-CC and A-NPog and angle ANS- Xi-Pm, POr-ANSPNS and DC-Xi-Pm (7.7 % each). In young women with a very wide type of face out of 13 possible built only 2 models of teleradiographic indicators (R² = 0.691 and 0.834) which were included to the second group depending on the indicators of the first group and 5 (R² = from 0.628 to 0.919) of 15 possible models of indicators which entered the third group depending on the indicators of the first and second groups. In young women with a very wide type of face, the constructed models of indicators included in the third group, depending on the indicators of the first and second groups, most often include the distance Xi-Pm (18.2 %), as well as the distance P-PTV and angles MeGo-NPog and POr-CFXi (9.1 % each). In young women with a wide type of face from 13 possible 5 models of teleradiographic indicators (R² = from 0.606 to 0.854) which were included in the second group depending on indicators of the first group and 7 (R² = from 0.607 to 0.888) from 15 possible models of indicators which were entered to the third group depending on the indicators of the first and second groups. In young women with a wide type of face, the constructed models of indicators included in the second group, depending on the indicators of the first group, most often include the distance Ar-Go (28.6 %) and the angle POr-NBa and the ratio S-ar:ar-Go (14.3 %), and to the models of indicators included in the third group depending on the indicators of the first and second groups – the distances A-NPog and Xi-Pm and the angle NBa-PtG (10.3 % each).

Assault-related facial fractures: does the injury mechanism matter?

This study clarified the injury characteristics and occurrence of associated injuries in patients with assault-related facial fractures. Data from 840 assault-related facial fracture patients were included; demographic factors, facial fracture type, associated injuries, alcohol use, and injury mechanisms were recorded. Assault mechanisms most often included combinations of different mechanisms (57.5%) and resulted in the victim falling (50.1%). The perpetrator was most commonly a stranger (52.5%) and acted alone (57.7%). A total of 123 patients (14.6%) had associated injuries, with the most common being traumatic brain injury. Associated injuries occurred most frequently in patients with combined fractures of the facial thirds (24.2%) and upper third fractures (42.9%). The most significant differentiating factors for associated injuries were the number of perpetrators, falling, the use of an offensive weapon, and if the events of the assault remained unknown. In adjusted logistic regression analyses, statistically significant associations with associated injuries were found for age (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.03–1.07; P < 0.001), falling due to the assault (OR 2.87, 95% CI 1.49–5.50; P = 0.002), and upper third facial fractures (OR 6.93, 95% CI 2.06–23.33; P = 0.002). A single punch also caused severe injuries and should therefore not be overlooked, as this can be as dangerous as other assault mechanisms.

Advanced Facial Rejuvenation After Bimaxillary Surgery in Three Different Facial Types.

Facial aging is the consequence of many mechanisms involving the bones and the "soft tissue" (skin, fat, ligaments, muscles, and periosteum) of the face such as downward migration of the soft tissue, adipose and muscular tissue atrophy, and skeletal resorption. The potential of orthognathic surgery (double jaw surgical advancement) of expanding the skeletal foundation to increase the facial drape support is now recognized and widely popularized by several authors. The aim of this study was to analyze the rejuvenation change of the face after bimaxillary advancement for orthognathic surgery, focusing on the previously mentioned stigmata of the middle and the lower third of the aging face. A retrospective monocentric chart review was conducted for all patients affected by aging signs of the face who underwent orthognathic surgery between January 2015 and December 2019 at the Face Surgery Center (Parma, Italy). During the postoperative follow-up examination, all patients underwent anthropometric photographs and esthetic assessment to evaluate facial rejuvenation after double jaw surgical advancement. After application of the exclusion criteria, the final study sample included 85 patients (53 females, 32 males). Eighty-three patients (97%) showed a degree of rejuvenation after maxillo-mandibular advancement (MMA); the score of the postoperative face was less than the score of the preoperative face. Two patients reported no significant postoperative change; none reported a more aging face, with a successful "reverse face-lift" occurred in 97% of our cases. "Reverse face-lift" by bimaxillary advancement is a surgical procedure which is indicated for a selected group of middle-aged patients with a diagnosis of bimaxillary skeletal retrusion or posterior divergence very motivated to an extreme rejuvenation; this procedure provides support for the facial mask resulting in whole facial rejuvenation.

The Frequency of Mandibular Third Molar Impaction in Different Types of Vertical Skeletal Faces

OBJECTIVE: To determine the frequency of mandibular third molar impaction in different vertical skeletal facial types. METHODOLOGY: Data was collected using pre-treatment records including orthodontic files, pre-treatment lateral cephalograms and OPGs of 90 orthodontic patients. Patients from both genders were included. The age group of selected patients was 18-30 years. Vertical skeletal malocclusion was measured using facial angle and mandibular plane angle on cephalogram to group the subjects into Mesiofacial, Brachyfacial and Dolichofacial patients. Third molar eruption status was assessed using OPG. RESULTS: Results showed that erupted third molars were mostly found in brachyfacial patients. Among 32 erupted mandibular third molars, 16 belong to brachyfacial, 11 belonged to mesiofacial and 5 belonged to dolichofacial group. Complete impaction of mandibular third molar was most common among dolichofacial patients. Among 29 completely impacted mandibular third molars, 14 belong to dolichofacial, 9 belonged to mesiofacial and 6 belonged to brachyfacial group. No significant difference was found for partially impacted third molars among the three groups of facial types. There was higher prevalence of mandibular third molar impaction in females as compared to males. CONCLUSION: Frequency of third molar impaction was found to be highest in dolichofacial patients and lowest in brachyfacial patients due to forward direction of mandibular growth contributing to greater resorption of the anterior border of ramus and the additional space required for third molar eruption.

Are chin and symphysis morphology facial type–dependent? A computed tomography-based study

The chin is a major determinant of the facial profile; hence, it plays a major role in orthodontics and orthognathic surgery. It is thus essential to follow and better understand its expression in different facial types. The major objectives of the current study were to characterize morphometrically the chin and symphysis and reveal their association with different facial types. Computed tomography scans of the head and neck of 311 adults (163 males, 148 females; age range, 18-95years) were classified into 3 facial types: short, average, and long. Height, width, projection, inclination, thickness, and area were measured on the chin and symphysis. The majority of the population (70%) manifested an average facial type; the other 30% were almost equally distributed between short and long facial types. The long facial type was more common among females and the short facial type among males. Chin projection, area, and size were significantly greater in short-faced patients. Chin width in males was similar for all facial types, whereas, in females, chin width was the widest in the short facial type and the narrowest in the long facial type. Symphysis height was significantly greater in long-faced patients in both sexes. The mandibular incisors' inclination relative to the mandibular plane was not significantly associated with the chin or symphysis morphology. Chin and symphysis morphology is facial type-dependent. Orthodontists and maxillofacial surgeons should be aware of the complex relationship between facial types and chin/symphysis size and shape when planning treatment.

Evaluation of Thickness of Buccal Attached Gingiva at Common Miniscrew Insertion Sites in Orthodontic Patients with Different Facial Types

Evaluation of Thickness of Buccal Attached Gingiva at Common Miniscrew Insertion Sites in Orthodontic Patients with Different Facial Types

Palatal bone thickness at the implantation area of maxillary skeletal expander in adult patients with skeletal Class III malocclusion: a cone-beam computed tomography study

BackgroundMaxillary skeletal expanders (MSE) is effective for the treatment of maxillary transverse deformity. The purpose of the study was to analyse the palatal bone thickness in the of MSE implantation in patients with skeletal class III malocclusion.MethodsA total of 80 adult patients (40 males, 40 females) with an average angle before treatment were divided into two groups, the skeletal class III malocclusion group and the skeletal I malocclusion group, based on sagittal facial type. Each group consisted of 40 patients, with a male to female ratio of 1:1. A cone-beam computed tomography scanner was employed to obtain DICOM data for all patients. The palatal bone thickness was measured at 45 sites with MIMICS 21.0 software, and SPSS 22.0 software was employed for statistical analysis. The bone thickness at different regions of the palate in the same group was analysed with one-way repeated measures ANOVA. Fisher’s least significant difference-t method was used for the comparison of pairs, and independent sample t test was employed to determine the significance of differences in the bone thickness at the same sites between the two groups.ResultsPalatal bone thickness was greater in the middle region of the midline area (P < 0.01), while the thickness in the middle and lateral areas in both groups was generally lower (P < 0.001). The bone in the anterior, middle, and posterior regions of the two groups became increasingly thin from the middle area toward the parapalatine region. The palatal bone was significantly thinner in the area 9.0 mm before the transverse palatine suture in the midline area, 9.0 mm before and after the transverse palatine suture in the middle area, and 9.0 mm after the transverse palatine suture in the lateral area.ConclusionThe palatal bone was thinner in patients with class III malocclusion than in patients with class I malocclusion, with significant differences in some areas. The differences in bone thickness should be considered when MSE miniscrews are implanted. The anterior and middle palatal areas are safer for the implantation of miniscrews, while the thinness of the posterior palatal bone increases the risk of the miniscrews falling off and perforating.

Analysis of correlation of 3-dimensional lip vermilion morphology and dentoskeletal forms in young Chinese adults on the basis of sex and skeletal patterns

The objective of this research was to evaluate the correlation between 3-dimensional (3D) lip vermilion (LV) morphology and skeletal patterns as well as incisor measurements in young Chinese adults. In all, 240 young adults were enrolled; these included 80 patients each with skeletal Class I, Class II, and Class III malocclusions, respectively. Each sagittal skeletal pattern included 40 male and 40 female subjects. Twenty-two 3D LV measurements were obtained from 3D facial scans. Skeletal and incisor measurements were evaluated on lateral cephalograms. Correlation and regression analysis were performed between soft and hard tissue measurements. Six of 22 LV measurements showed significant differences between male and female subjects. The 3D LV morphology showed significant differences with respect to different skeletal patterns and sex. Adults with skeletal Class III malocclusion tended to have thinner upper vermilion and fuller lower vermilion than subjects with skeletal Class II and III malocclusion. The mandibular plane angle negatively correlated with the upper-lower vermilion midsagittal curve length and surface area ratio in adults with skeletal Class I and II malocclusion, yet the vertical facial skeletal type showed no correlation in adults with skeletal Class III malocclusion. The vermilion angle, central bow angle, vermilion height, vermilion midsagittal curve length, vermilion height and width ratio, and vermilion surface area showed a significant correlation with incisor measurements. Regression analysis found that the ANB angle was an important factor affecting the upper and lower vermilion midsagittal curve length and surface area ratio. Further, the vermilion height and height and width ratio were closely correlated with the interincisal (U1/L1) angle, whereas the central bow angle was closely correlated with the maxillary incisor torque. Most LV morphology variables were correlated to skeletal patterns and incisor measurements. Skeletal Class III malocclusion showed significant differences in vermilion morphology. Both the sagittal and vertical skeletal pattern have effects on vermilion proportion. The incisor torque was closely correlated to vermilion shape and central bow angle and might influencethe vermilion esthetics. However, the proportion of the upper and lower vermilion was mainly affected by the ANB angle.

O perfil facial e a prevalência de canal mandibular bífido

Objetivo: Avaliar a prevalência dos canais mandibulares bífidos (CMB) e correlacioná-los com os tipos faciais (TF) por meio de tomografia computadorizada de feixe cônico (TCFC). Material e método: A amostra, composta por 180 hemimandíbulas (90 pacientes), foi determinada por: TF, sexo, idade e lado da face. O TF foi determinado utilizando o índice VERT de Ricketts. As TCFC foram dispostas em três grupos de acordo com os TF: 30 pacientes braquifaciais, 30 mesofaciais e 30 dolicofaciais. Os CMB foram classificados de acordo com Naitoh et al. (2011). As imagens foram classificadas e avaliadas por um radiologista treinado, utilizando os softwares Dolphin Imaging® 11.0 e XoranCat®. A comparação entre os grupos em relação ao sexo, lado acometido e classe do CMB foi feita pelo teste Qui-quadrado ou Exato de Fisher; a influência da idade em relação ao sexo e presença de CMB, pelo teste de Mann-Whitney e, em relação ao TF, pelo teste de Kruskal-Wallis. A relação entre o sexo dos pacientes e presença do CMB, pelo teste Exato de Fisher. O nível de significância considerado foi de 5% para todos os testes. Resultados: A proporção de pacientes com CMB na amostra foi de 14.4%, sendo o mais frequente o tipo C sentido alveolar (53.8%), seguidos dos tipos D sentido retromolar (15.4%), tipo E sentido lingual (15.4%) e tipo F sentido base da mandíbula (7.7%). Quando o CMB estava presente, não houve predominância de lado nem influência pelo sexo. Conclusão: O TF não afeta a presença ou o tipo de CMB. Objetivo: Avaliar a prevalência dos canais mandibulares bífidos (CMB) e correlacioná-los com os tipos faciais (TF) por meio de tomografia computadorizada de feixe cônico (TCFC). Material e método: A amostra, composta por 180 hemimandíbulas (90 pacientes), foi determinada por: TF, sexo, idade e lado da face. O TF foi determinado utilizando o índice VERT de Ricketts. As TCFC foram dispostas em três grupos de acordo com os TF: 30 pacientes braquifaciais, 30 mesofaciais e 30 dolicofaciais. Os CMB foram classificados de acordo com Naitoh et al. (2011). As imagens foram classificadas e avaliadas por um radiologista treinado, utilizando os softwares Dolphin Imaging® 11.0 e XoranCat®. A comparação entre os grupos em relação ao sexo, lado acometido e classe do CMB foi feita pelo teste Qui-quadrado ou Exato de Fisher; a influência da idade em relação ao sexo e presença de CMB, pelo teste de Mann-Whitney e, em relação ao TF, pelo teste de Kruskal-Wallis. A relação entre o sexo dos pacientes e presença do CMB, pelo teste Exato de Fisher. O nível de significância considerado foi de 5% para todos os testes. Resultados: A proporção de pacientes com CMB na amostra foi de 14.4%, sendo o mais frequente o tipo C sentido alveolar (53.8%), seguidos dos tipos D sentido retromolar (15.4%), tipo E sentido lingual (15.4%) e tipo F sentido base da mandíbula (7.7%). Quando o CMB estava presente, não houve predominância de lado nem influência pelo sexo. Conclusão: O TF não afeta a presença ou o tipo de CMB.

Association between degenerative temporomandibular joint disorders, vertical facial growth, and airway dimension

BackgroundThe goal of this study was to determine whether preexisting degenerative temporomandibular joint (TMJ) disorders are associated with hyperdivergent facial phenotype and decreased airway dimensions. MethodsCone-beam computed tomography scans of adult female and male individuals, 16 years of age and older, distributed in a case group defined as those with degenerative temporomandibular joint disorder (dTMJD; n = 31) or controls with normal TMJ findings (n = 242) were included. Odds ratios were calculated based on facial type and gender. Analysis of variance was used to compare the airway volume and cross section and mandibular measurements between the groups. ResultsCondylar, ramus, and mandibular heights were significantly smaller in the case group compared with the control group. The odds of having a long face subject was significantly higher (P < 0.00001) in the dTMJD group than in the control group with 81% of the dTMJD subjects versus 11% of the control group having long vertical facial dimensions. The smallest cross-sectional area of the airway of the dTMJD group was significantly narrower (P < 0.0361) compared with the controls. Within the control group, ramus height and mandibular alveolar housing for central incisors were significantly smaller (P < 0.0001; P < 0.007) in the long face subjects. ConclusionsThe study shows that a long facial type is associated with findings of degenerative TMJ disorders and related condylar growth disturbances. These degenerative and growth changes may contribute to specific skeletal and dentofacial adaptations resulting in smaller condylar process, mandibular ramus, and body height; thinner alveolar housing at the lower incisor region; and smaller cross-sectional area of the airway.