Vertical Facial Pattern Research Articles

Relationship between the maxillofacial skeletal pattern and the morphology of the mandibular symphysis: Structural equation modeling.

ObjectiveThe purpose of this study was to investigate the relationship between the facial skeletal patterns and the shape of the mandibular symphysis in adults with malocclusion by using a structural equation model (SEM).MethodsNinety adults who had malocclusion and had records of facial skeletal measurements performed using cone-beam computed tomography were selected for this study. The skeletal measurements were classified into three groups (vertical, anteroposterior, and transverse). Cross-sectional images of the mandibular symphysis were analyzed using generalized Procrustes and principal component (PC) analyses. A SEM was constructed after the factors were extracted via factor analysis.ResultsTwo factors were extracted from the transverse, vertical, and anteroposterior skeletal measurements. Latent variables were extracted for each factor. PC1, PC2, and PC3 were selected to analyze the variations of the mandibular symphyseal shape. The SEM was constructed using the skeletal variables, PCs, and latent variables. The SEM showed that the vertical latent variable exerted the most influence on the mandibular symphyseal shape.ConclusionsThe relationship between the skeletal pattern and the mandibular symphysis was analyzed using a SEM, which showed that the vertical facial skeletal pattern had the highest effect on the shape of the mandibular symphysis.

Relationship of the airway size to the mandible distance in Chinese skeletal Class I and Class II adults with normal vertical facial pattern.

This study aims to evaluate the pharyngeal airway dimensions among Chinese adults in relation to Class I and Class II facial skeletal patterns using three-dimensional cone-beam computed tomography (CBCT) images. A total of 156 initial CBCT images were evaluated, which were classified into skeletal Class I and Class II according to ANB angle with mean (SD) age being 22.56 ± 4.0 years and 22.32 ± 3.6 years. The pharyngeal airway volume, airway area, minimum cross-sectional area (MCA) and the distance from uvula (tip of the soft palate) to mental spine (U-MS distance) were assessed with Dolphin imaging software. Compared with Class I group, Class II group displayed significantly smaller pharyngeal airway volume, airway area and MCA (P <.01, P =0.03, and P =0.008, respectively), and shorter U-MS distance (P <.001). Comparing gender subgroups, the female subgroup showed the smallest airway measurement. Spearman correlation test results showed that the airway volume and area had a significant positive correlation with U-MS distance (r = 0.22, P = 0.005, and r = 0.28, P < 0.005, respectively) and negative correlation with ANB angle (r = -0.23, P = 0.002, and r = -0.21, P = 0.007, respectively). Pharyngeal airway volume, airway area, MCA, and the U-MS distance were smaller in skeletal Class II than Class I Chinese adult subjects and lower in female Class II subgroup. Additionally, there was a correlation observed between the mandibular distance (U-MS), ANB angle and airway size.

Relationship between masseter muscle thickness and maxillofacial morphology in pre-orthodontic treatment patients

This study investigated the relationship between masseter muscle thickness and cephalometric facial parameters in pre-orthodontic treatment patients. Participants were grouped according to their vertical facial patterns into low, normal, and high angle facial patterns using standardised lateral cephalometric radiograph. Associations between the masseter muscle thickness (measured using ultrasonography) and different vertical facial patterns were analysed. Masseter muscle thickness in low angle subjects were significantly higher than the normal and high angle cases during both relaxation and contraction phases (P<0.001). Masseter muscle thickness correlated positively with Jarabak ratio and ramus thickness (R1/R2) during both phases, and negatively with LAFH, FMA, MMPA and gonial angle.

Long-term stability of curve of Spee levelled with continuous archwires in subjects with different vertical patterns: a retrospective study.

The aim of the study was to evaluate the curve of Spee (COS) stability in patients treated with continuous archwires with different vertical patterns. The study sample consisted of 60 patients (28 males, 32 females; mean age 19.8 ± 1.4 years) presenting with COS depth of at least2 mm at baseline. For each subject, lateral cephalograms and dental casts were available before treatment (T1), at the end of orthodontic therapy (T2), and 2 years after the end of treatment (T3). All subjects were divided into three groups according to vertical facial patterns. Cephalometric parameters were used to evaluate the dental movements after treatment. COS depth was measured on digital casts. Mean differences between vertical facial subgroups were contrasted by means of analysis of variance test (P < 0.01). In low-angle subjects, COS levelling occurred through advancement and intrusion of lower incisors, whereas in high-angle patients, the COS was flattened through extrusion and uprighting of lower posterior teeth. In the low-angle group, a significant relapse of lower incisors inclination was observed. Differently, the high-angle group exhibited a greater stability of COS obtained by stable extrusion of posterior teeth. The long-term instability of flared incisors determined the relapse of overbite and COS depth in the low-angle group.

Correlation between the cross-sectional morphology of the mandible and the three-dimensional facial skeletal pattern: A structural equation modeling approach.

To clarify the relationship between the cross-sectional morphology of the mandible and vertical, transverse, and anteroposterior facial skeletal patterns using statistical shape analysis and structural equation modeling (SEM). We used 150 cone beam computed tomography (CBCT) images to obtain three-dimensional (3D) facial landmarks and cross-sectional images of the mandible. The morphology of the inner and outer cortices of the mandible was analyzed using statistical shape analysis, including generalized Procrustes analysis and principal component analysis (PCA). Factor analysis was performed to determine factors pertaining to the skeletal measurements and shape variations for the inner and outer cortices, following which a structural equation model was constructed. Using factor analysis, characteristics of the vertical, transverse, and anteroposterior facial skeletal patterns were determined. PCA of the cross-sectional morphology of the mandible revealed 70% of the cumulative proportion by PC1 and PC2 after generalized Procrustes superimpositions. SEM showed complex relationships between the facial skeletal patterns and variations in the cross-sectional morphology of the mandibular cortices. The influence of the transverse factors on the outer cortex as a latent variable was relatively significant ( P = .057). However, the influence of the vertical factors on the outer and inner cortices was not significant. The transverse skeletal pattern is associated with the morphology of the outer cortex of the mandible.

Three-dimensional treatment outcomes in Class II patients with different vertical facial patterns treated with the Herbst appliance.

The aims of this study were to evaluate, using 3-dimensional superimposition techniques, the skeletal changes in Class II subjects with different vertical facial patterns treated with the Herbst appliance and to compare these skeletal changes to those of Class II controls treated with elastics. Sixteen Herbst patients who met the inclusion criteria were divided into 2 equal groups based on vertical facial pattern as determined by the Frankfort mandibular plane angle (brachyfacial,≤22°; mesofacial, 23°-29°) and had cone-beam computed tomographs taken before treatment, 8weeks after Herbst appliance removal, and after subsequent fixed appliance treatment. Eleven Class II control patients treated with fixed appliances and elastics had cone-beam computed tomographs taken before and after treatment. Three-dimensional models were generated from the cone-beam computed tomography images, registered on the anterior cranial bases, and analyzed using color maps and point-to-point measurements. There were minimal differences in treatment response between the 2 Herbst groups across all skeletal parameters measured. The Herbst subjects showed a greater inferior displacement of anterior nasal spine compared with the Class II controls (Herbst brachyfacial, -1.44mm; Herbst mesofacial, -1.95mm) with other maxillary changes being clinically insignificant. The Herbst subjects showed greater inferior displacement of B-point compared with the Class II controls (Herbst brachyfacial, -2.59mm; Herbst mesofacial, -2.75mm). There were no statistically significant differences in mean linear mandibular measurements. All groups showed a trend toward posterior displacement of the condyles and glenoid fossae from the start to the end of treatment, with no significant differences across the 3 groups. There were minimal differences in the changes in gonial angle and Frankfort mandibular plane angle across all groups. Approximately 2years after Herbst treatment, the Herbst subjects with different vertical facial patterns showed similar patterns of skeletal change compared with the Class II controls treated with elastics.

Three-dimensional evaluation of dentofacial transverse widths of adults with various vertical facial patterns.

The purpose of this study was to investigate maxillomandibular transverse widths and molar inclinations of adults with hypodivergent, normodivergent, and hyperdivergent facial patterns using cone-beam computed tomography. We evaluated Class I subjects (55 men, 66 women) who were divided into hypodivergent (<27°), normodivergent (28°-37°), and hyperdivergent (>38°) groups by their mandibular plane angles. Frontal and coronal views of the images were analyzed. Sex differences, vertical facial pattern differences, and related factors were assessed with independent 2-sample t tests, 1-way analysis of variance followed by post hoc Tukey tests, and Pearson correlation analysis. The hypodivergent group had greater maxillary alveolar widths 7mm apically from the alveolar crest. The intermolar widths and molar inclinations showed no significant differences among the groups. As the mandibular plane angles increased, interjugular widths, transverse mandibular widths, and buccolingual maxillary alveolar widths at the midroot level decreased, whereas the maxillomandibular width differences and palatal heights increased im both sexes. An increase in the mandibular plane angle is associated with tendencies of narrow mandibular arches, thinner maxillary alveolar bones at the midroot level, and higher palatal arches in both sexes. Intermolar widths and molar inclinations were not significantly affected by vertical facial patterns.

Assessment of lower incisor alveolar bone width using cone-beam computed tomography images in skeletal Class III adults of different vertical patterns.

ObjectiveThis study was performed to investigate the alveolar bone of lower incisors in skeletal Class III adults of different vertical facial patterns and to compare it with that of Class I adults using cone-beam computed tomography (CBCT) images.MethodsCBCT images of 90 skeletal Class III and 29 Class I patients were evaluated. Class III subjects were divided by mandibular plane angle: high (SN-MP > 38.0°), normal (30.0° < SN-MP < 37.0°), and low (SN-MP < 28.0°) groups. Buccolingual alveolar bone thickness was measured using CBCT images of mandibular incisors at alveolar crest and 3, 6, and 9 mm apical levels. Linear mixed model, Bonferroni post-hoc test, and Pearson correlation analysis were used for statistical significance.ResultsBuccolingual alveolar bone in Class III high, normal and low angle subjects was not significantly different at alveolar crest and 3 mm apical level while lingual bone was thicker at 6 and 9 mm apical levels than on buccal side. Class III high angle group had thinner alveolar bone at all levels except at buccal alveolar crest and 9 mm apical level on lingual side compared to the Class I group. Class III high angle group showed thinner alveolar bone than the Class III normal or low angle groups in most regions. Mandibular plane angle showed negative correlations with mandibular anterior alveolar bone thickness.ConclusionsSkeletal Class III subjects with high mandibular plane angles showed thinner mandibular alveolar bone in most areas compared to normal or low angle subjects. Mandibular plane angle was negatively correlated with buccolingual alveolar bone thickness.

A cephalometric study of the skeletal and dento-alveolar effects of the modified Louisiana State University activator in Class II malocclusion.

To analyse the skeletal and dento-alveolar effects of the modified Louisiana State University activator (MLSUA) in Class II treatment. A test group of 46 participants (25 females, 21 males) with Class II malocclusion treated with MLSUA followed by fixed appliances was compared with a matched Class II control group. Lateral cephalograms were taken at T1 (initial records), T2 (completion of MLSUA treatment), and T3 (before deband). The participants were also divided into two groups: pre-pubertal and pubertal according to skeletal maturity and three groups of different vertical facial patterns at the start of the treatment: brachyfacial, mesofacial, and dolichofacial. Statistical comparisons were performed with t-tests and analysis of variance (ANOVA). Statistically significant supplementary mandibular growth (Co-Gn) in the test group (2.6 mm) was associated with improvement of overjet (OJ), overbite (OB), and molar relationship. Short-term mandibular growth was greater in pubertal than pre-pubertal groups (2.4 mm, P < 0.05). Mandibular incisors retroclined by 2.1 degrees after MLSUA treatment. The brachyfacial group showed greater reduction in the ANB angle and forward movement of pogonion. Mandibular, palatal, and occlusal plane angles showed insignificant change regardless of the facial type. MLSUA treatment corrected the Class II malocclusion by accelerating mandibular growth in the short-term with minimal dento-alveolar compensation, and the correction was maintained before deband. The treatment may be more effective if started at puberty. The mandibular, palatal, and occlusal planes remained stable throughout the treatment. Brachyfacial patients showed more favourable horizontal growth.

Relationships of vertical facial pattern, natural head position and craniocervical posture in young Chinese children

Objective: To investigate relationships of vertical facial patterns, natural head position (NHP), and craniocervical posture in young Chinese children with skeletal Class I relationship.Methods: Ninety-four patients with skeletal Class I relationship were classified into low, average, and high angle groups according to their mandibular plane angle (NSL/ML). Cephalometric radiographs in NHP were taken. Variables representing vertical and sagittal craniofacial morphology, head posture, and craniocervical posture were measured and compared.Results: Inclinations of the mandible to the true vertical and cervical column were smallest in the high angle group and largest in the low angle group. Other variables representing head posture and craniocervical posture were largest in the high angle group, smallest in the low angle group. Inclinations of ramus to cervical column were largest in the high angle group and smallest in the low angle group.Discussion: Subjects with large NSL/ML angles showed extended head and craniocervical posture, while subjects with small NSL/ML angles exhibited flexed head and craniocervical posture.

TAD – Transpalatal Arch-MOD Combination System: An Effective Tool in the Nonsurgical Management of Individuals with Vertical Facial Patterns and Gummy Smiles

TAD – Transpalatal Arch-MOD Combination System: An Effective Tool in the Nonsurgical Management of Individuals with Vertical Facial Patterns and Gummy Smiles

TAD – Transpalatal Arch-MOD Combination System: An Effective Tool in the Nonsurgical Management of Individuals with Vertical Facial Patterns and Gummy Smiles

The treatment of vertical facial patterns with gummy smiles in adults has long been a challenge to the orthodontist. Before the advent of microimplants, correction of such complex skeletal problems in adults was only possible with the help of orthognathic surgery. Orthognathic surgery in such situations aimed at LeFort I impaction of the maxillary dentoalveolar segment followed by counterclockwise rotation of the mandible, thereby improving the gummy smile and chin prominence. With the introduction of skeletal anchorage systems and microimplants in the last decade and the promising results that it has shown over the years, we as orthodontist now believe that surgery can definitely be avoided in selected cases when temporary anchorage devices are used – orthognathic surgery such as orthodontics. Microimplants have therefore expanded the envelope of discrepancy on which the orthodontist can work on. This case report focuses on the use of the TAD – Transpalatal arch-MOD combination system for nonsurgical management of adults with vertical facial pattern and gummy smile and details of the biomechanical perspectives associated with it.

The nasopalatine canal, a limiting factor for temporary anchorage devices: a cone beam computed tomography data study.

There is only little knowledge on topographical predispositions of the nasopalatine canal as a limiting factor for insertion of mid-palatal temporary anchorage devices (TAD). The purpose of the study was to assess the course of the nasopalatine canal, the adjacent vertical bone quantity, and whether it might differ among vertical facial types, using pre-existing cone beam computed tomography (CBCT) scans. Out of a consecutive sample collected from April 2008 to August 2012, only patient data depicting both upper and lower jaw completely were evaluated retrospectively. The linear measurements were taken on the respective midsagittal view perpendicular to the palate at the level of 1st molar/2nd premolar (5/6), 2nd premolar/1st premolar (4/5), and 1st premolar/canine (3/4). Screen-prints were used to measure the inclination of the nasopalatine canal in relation to the maxillary jaw base. Maxillary and mandibular divergence was assessed on rendered lateral cephalograms. Out of 3869 pre-existing consecutive CBCT scans, data from 398 patients met the inclusion criteria and could be extracted. The mean vertical bone was 4.09 mm at the 5/6 level, 5.22 mm at the 4/5 level, and 3.14 mm at the 3/4 level, respectively. A statistically significant negative correlation exists between jaw divergence and the canal angulation with regard to the maxillary base. A statistically significant negative correlation exists between the canal angulation and vertical bone measurements at the 4/5 and 3/4 levels. Vertical bone volume is sufficient at 4/5 level for TAD placement, and bares only a small risk for neuro-sensory impairment. Therefore, only in rare cases a CBCT is justified for palatal implant placement. The course of the nasopalatine canal is negatively correlated with the vertical skeletal facial pattern pointing to the fact that in hypodivergent patients a TAD might be placed in a more distal or paramedian region.

Comparison of airway dimensions in skeletal Class I malocclusion subjects with different vertical facial patterns.

ABSTRACTObjective: The aim of this study was to compare upper airway widths among skeletal Class I malocclusion subjects with different vertical facial patterns. Methods: The sample included a total of 99 lateral cephalograms of post pubertal individuals (18.19 ± 1.76 years old). The vertical facial pattern was determined by the Vert index. The McNamara method was used to quantify upper airway widths. ANOVA test and Student’s t test for independent groups were used, when normal distribution was not supported Kruskal-Wallis test and U-Mann-Whitney test were used. A multiple linear regression analysis was also performed. Results:Statistically significant differences in several nasopharyngeal widths were found among the distinct vertical facial patterns. Subjects with brachyfacial pattern presented larger nasopharyngeal widths than subjects with mesofacial (p= 0.030) or dolichofacial (p= 0.034) patterns. The larger the Vert value, the larger the nasopharyngeal widths (R2= 26.2%, p< 0.001). At the level of oropharynx no statistically significant differences were found. Conclusion: It was concluded that nasopharyngeal linear anteroposterior widths in Class I malocclusion brachyfacial are larger than in mesofacial and dolichofacial individuals. The Vert index only explained 25% of the total variability. No correlation was found for the oropharyngeal widths.

Etiology and treatment options of anterior open bite in growing patients: a narrative review

Anterior open bite represents a malocclusion that is still under study because of the still lacking evidence about etiology and best treatment options in growing subjects according to success rate and stability. Etiology involves the interaction of environmental factors such as prolonged sucking habits, mouth breathing, tongue or lip thrusting, tongue dimension, eruption disturbances with a genetically determined vertical facial growth pattern. The treatment options for the early treatment of anterior open bite are still controversial. The aim of this study was to evaluate the actual available evidence on treatments of anterior open bite in the mixed dentition in order to assess the effectiveness of the early treatment in reducing open bite, the most efficacious treatment strategy and the stability of the results.

Dentofacial traits in association with lower incisor alveolar cancellous bone thickness: A multiple regression analysis.

To identify dentofacial anatomic traits associated with lower incisor cancellous bone thickness (LICBT) and then to assess their separate contributions and their combined contributions to the variation in LICBT. A consecutive sample of cone beam computed tomography (CBCT) data taken in a university hospital within the same setting was retrospectively reviewed. Within the sample, CBCT data of 252 eligible subjects were reconstructed and measured for LICBT, facial traits, and mandibular symphyseal traits. A backward multiple linear regression was employed to explore the association between LICBT and seven representative dentofacial traits. Four dentofacial traits (vertical facial pattern, transverse jaw relationship, lower incisor cervical diameter, and mandibular symphyseal width) were identified as significantly associated with LICBT. The combination of these four factors could predict 64.3% of variations in LICBT (adjusted R2 = 0.643). Further comparison of LICBT among different transverse jaw relationships suggested that the LICBT of the normal (5.94 ± 1.58 mm) group and the inferior convergent group (5.38 ± 1.32 mm) were significantly larger than that of the crossbite group (4.34 ± 1.27 mm) and the superior convergent group (4.53 ± 1.67 mm). The bony support of lower incisors is significantly associated with several dentofacial traits. Reduced lower incisor bony support was statistically associated with increased vertical facial pattern, transverse jaw discrepancy, thinner mandibular symphyseal width, and smaller lower incisor cervical diameter.

Dentoalveolar Heights in Vertical and Sagittal Facial Patterns.

To determine and compare the mean dentoalveolar heights (mm) in different vertical and sagittal facial patterns. Cross-sectional study. Orthodontics Clinic, The Aga Khan University Hospital, Karachi, from September to November 2013. Subjects, aged 15 - 20 years, having fully erupted first permanent molars and central incisors were included in the study from orthodontic records. The pretreatment cephalographs of subjects were traced manually over an illuminator. The various parameters like angles and dentoalveolar heights were measured and recorded on data collection form. Mean value ± SD for the variables were generated. ANOVAwas used to compare the means of dentoalveolar heights among the vertical and sagittal facial patterns. Post Hoc Bonferroni test was applied to show difference among the three vertical and three sagittal facial patterns. P-value equal to or less than 0.05 was taken as statistically significant. The mean age of subjects was 15.8 ±3.2 years in vertical group and 16.3 ±2.9 years in sagittal group. There was statistically significant difference (p=0.008) for the upper anterior dentoalveolar height (UADH) among vertical groups, with statistically significant difference for UADH between hyperdivergent and normodivergent (p=0.04) and hyperdivergent and hypodivergent (p=0.01) facial patterns. The UADH were significantly greater in the hyperdivergent group as compared to both the normodivergent and hypodivergent groups. The sagittal groups showed no statistically significant difference for dentoalveolar heights.

Abstract: Can a Surgery-First Orthognathic Approach Reduce the Total Treatment Time?

INTRODUCTION: A traditional orthognathic approach requires presurgical orthodontic treatment for an average of approximately 17 months,1 followed by surgery and postsurgical orthodontic treatment for approximately 6–12 months. Therefore, the total treatment time for the conventional orthognathic approach takes approximately 18–36 months.2–4 Because traditional orthognathic surgery requires 2–3 years to complete, it is a rarely adopted procedure. Therefore, shortening the total treatment time would be extremely beneficial for patients. Although presurgical orthodontic treatment has been approved as an inevitable process for stable orthognathic correction before surgery, recent advances in the application of mini-screws and presurgical simulational orthodontic management skills on a dental model show that it is possible to perform a surgery-first orthognathic approach without presurgical orthodontic treatment.5 MATERIALS AND METHODS: We assessed 45 consecutive Asian patients with skeletal class III dentofacial deformities with surgery-first orthognathic surgery compared to 52 patients with conventional two-jaw orthognathic surgery. Using cephalometric landmark data for the patients with a surgery-first approach, we analyzed postoperative changes in vertical and horizontal facial, denture, and soft tissue patterns. Assuming that tooth extraction is a factor that affects the total treatment time, both groups were divided into two subgroups. RESULTS: The treatment duration of the surgery-first group was significantly less than that of the orthodontics-first group. Overall, the analysis revealed that the total treatment time period in the surgery-first orthognathic approach averaged 14.6 months compared to 22.0 months of treatment in an orthodontic-first orthognathic approach. Among the surgery-first cases without tooth extraction, the average treatment interval was only 13.6 months versus 24.8 months for the six that required tooth extraction (p < 0.001). In contrast, the average treatment period of traditional orthodontics-first cases without tooth extraction was roughly comparable to the nine cases that required tooth extraction (21.7 months vs. 21.6 months, respectively). The difference between immediate postoperative and preoperative, postoperative and immediate postoperative cephalometric data revealed factors that have correlation with total treatment duration. CONCLUSION: Surgery-first orthognathic surgery can dramatically shorten the total treatment time with no major complications. By analyzing the cephalometric landmark data we identified several possible factors that have an effect on the total treatment time. DISCLOSURES/FINANCIAL SUPPORT:None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this manuscript. REFERENCES: 1. Luther F, Morris DO, Hart C: Orthodontic preparation for orthognathic surgery: how long does it take and why? A retrospective study. Br J Oral Maxillofac Surg 41:401–406, 2003. 2. Van Sickels JE, Loftus MJ, Weiss WW, Jr: Orthognathic surgery: a team approach. Bull Phila Cty Dent Soc. 45:8–9, 1979. 3. Slavnic S, Marcusson A: Duration of orthodontic treatment in conjunction with orthognathic surgery. Swed Dent J. 34:159–166, 2010. 4. Dowling PA, Espeland L, Krogstad O, Stenvik A, Kelly A: Duration of orthodontic treatment involving orthognathic surgery. Int J Adult Orthodon Orthognath Surg. 14:146–152, 1999. 5. Choi JW, Lee JY, Yang SJ, Koh KS: The reliability of a surgery-first orthognathic approach without presurgical orthodontic treatment for skeletal class III dentofacial deformity. Ann Plast Surg. 74:333–341, 2015.

Factors Affecting the Clinical Success Rate of Miniscrew Implants for Orthodontic Treatment.

The purpose of this study was to evaluate the various factors that influence the success rate of miniscrew implants used as orthodontic anchorage. Potential confounding variables examined were sex, age, vertical (FMA) and sagittal (ANB) skeletal facial pattern, site of placement (labial and buccal, palatal, and retromandibular triangle), arch of placement (maxilla and mandible), placement soft tissue type, oral hygiene, diameter and length of miniscrew implants, insertion method (predrilled or drill-free), angle of placement, onset and strength of force application, and clinical purpose. The correlations between success rate and overall variables were investigated by logistic regression analysis, and the effect of each variable on the success rate was utilized by variance analysis. One hundred fourteen patients were included with a total of 253 miniscrew implants. The overall success rate was 88.54% with an average loading period of 9.5 months in successful cases. Age, oral hygiene, vertical skeletal facial pattern (FMA), and general placement sites (maxillary and mandibular) presented significant differences in success rates both by logistic regression analysis and variance analysis (P < .05). To minimize the failure of miniscrew implants, proper oral hygiene instruction and effective supervision should be given for patients, especially young (< 12 years) high-angle patients with miniscrew implants placed in the mandible.

Relationship of craniofacial morphology in3-dimensional analysis of the pharynx.

Pharynx dimensions may vary according to the position and morphology of the mandible. The aim of this study was to test the hypothesis that craniofacial morphology affects pharyngeal volume and its cross-sectional areas. Seventy-four subjects (38 men, 36 women) aged 18 to 56years (mean±SD 32.8±1.8years) were scanned with a cone-beam computed tomography unit and had facial profile photographs taken. All participants were classified according to skeletal anteroposterior (Class II and Class III) and vertical facial patterns (brachyfacial, mesofacial, and dolichofacial). Facial profile analyses and pharyngeal volume and cross-sectional area determinations were performed. The soft palate cross-sectional area of the oropharynx was significantly greater in the Class III patients. The upper facial third (trichion to soft tissue glabella/facial height) correlated negatively with pharyngeal volume and with soft palate cross-sectional area in the oropharynx. Alternatively, the midfacial third (soft tissue glabella to subnasale/facial height) correlated positively with soft palate cross-sectional area of the oropharynx. No significant differences across sexes and facial patterns regarding pharyngeal volume were found (P>0.05). The soft palate cross-sectional area is larger in skeletal Class III subjects. It seems that analysis of the facial profile focusing on the proportions of the facial thirds allows for inferences on pharyngeal dimensions. However, anteroposterior skeletal facial type and vertical facial pattern do not seem to affect pharyngeal volume.