Comparison of transverse analysis between posteroanterior cephalogram and cone-beam computed tomography

The coordination of bimaxillary alveolar arch widths in subjects with normal occlusion or posterior crossbite: A CBCT retrospective study

OBJECTIVES

To propose a method for evaluating the coordination of maxillomandibular alveolar arch in transverse dimension with cone-beam computed tomography (CBCT) and to apply this method to subjects with normal occlusion at different dentition stages or transverse discrepancy.

MATERIALS AND METHODS

Digital data of 130 patients with normal occlusion at different dentition stages or transverse discrepancy were collected for three-dimensional reconstruction. The patients with normal occlusion were divided into Group 1 (>16 years) and Group 2 (≤16 years) based on their age. Adult patients with posterior crossbite were divided into the Group 3. According to the proposed method, the average alveolar arch coordination angle (AACA) and other parameters were analysed in each group. Group 1 was considered as the control group and compared with Group 2 and Group 3.

RESULTS

Significant differences were observed in the maxillary posterior segment width among patients with normal occlusion. Group 3 demonstrated increased AACA and mandibular alveolar arch width compared with the normal occlusion group. Pearson correlation analysis indicated a positive relationship between maxillomandibular alveolar arch widths in the normal occlusion groups, with a strong correlation between AACA and the disparity in maxillomandibular widths.

CONCLUSION

Adults with normal occlusion exhibit significantly wider maxillary posterior alveolar arches than adolescents, with no marked difference in mandibular widths. The posterior crossbite group showed broader mandibular alveolar arches. There was a strong correlation between AACA and the difference in maxillomandibular widths. This study's method shows potential value for orthodontic transverse diagnosis.

Basal and dentoalveolar transverse parameters in different sagittal and vertical malocclusions in adults: a comparative study

OBJECTIVE

This study sought to three-dimensionally (3D) evaluate the maxillomandibular basal bone and dentoalveolar widths using cone-beam computed tomography (CBCT) scans in adult Chinese populations with different vertical and sagittal facial skeletal patterns whilst no apparent posterior dental crossbite.

MATERIALS AND METHODS

The retrospective cross-sectional comparative study enrolled CBCT images of 259 adult patients (125 males and 134 females). The subjects were divided into the hyperdivergent(n = 82), hypodivergent(n = 88), and normodivergent(n = 89) groups based on the Jarabak ratio (S-GO/N-Me), which were further divided into three subgroups of skeletal Class I, II and III, based on both the ANB angle and AF-BF parameters. ANOVA was used to analyze the extracted data of the studied groups. The intra- and inter-observer reliability was analyzed using the intra-class correlation coefficient (ICC).

RESULTS

In all three vertical facial skeletal patterns, the skeletal Class II had significantly smaller mandibular basal bone width compared to skeletal Class I and Class III, both at the first molar and first premolar levels. The skeletal Class III seemed to have smaller maxillary basal bone width compared to skeletal Class I and Class II malocclusions; however, a significant difference was found only in the normodivergent pattern. As for the dentoalveolar compensation, it was most notable that in the hypodivergent growth pattern, the skeletal Class II had significantly smaller maxillary dentoalveolar width compared to the Class I and Class III groups, both at the first molar and first premolar levels.

CONCLUSIONS

Based on the sample in the present study, skeletal Class II has the narrowest mandibular basal bone regardless of the vertical facial skeletal pattern.

CLINICAL RELEVANCE

For Chinese adults with no apparent transverse discrepancy, the maxillomandibular basal bone and dentoalveolar widths are revealed in specific categories based on different vertical and sagittal facial skeletal patterns. In diagnosis and treatment planning, particular attention should be paid to skeletal Class II for possibly existing mandibular narrowing.

The Facial Characteristics of Individuals with Posterior Crossbite: A Cross-Sectional Study

Facial morphology is known to be influenced by genetic and environmental factors. Scientific evidence regarding facial parameters in patients with posterior crossbite is lacking. This study aimed to investigate the association between posterior crossbite and facial parameters. This cross-sectional study included 34 adolescents with and 34 adolescents without posterior crossbite in the age range from 13 to 15 years. Facial surface scans were acquired with a 3dMD imaging system, and landmark-based analysis was performed. Data were analyzed using the Mann-Whitney U test and Spearman's correlations. Individuals in the control group had lower face heights (females: p = 0.003, r = 0.45; males: p = 0.005, r = 0.57). The control group females presented with smaller intercanthal width (p = 0.04; r = 0.31) and anatomical nose width (p = 0.004; r = 0.43) compared with the crossbite group females. The males in the control group had wider nostrils. In the control group, significant correlations among different facial parameters were more common, including the correlations between eye width and other transversal face measurements. On the contrary, the facial width was correlated with nasal protrusion (r = 0.657; p < 0.01) and the morphological width of the nose (r = 0.505; p < 0.05) in the crossbite group alone. In both groups, the philtrum width was linked with the anatomical and morphological widths of the nose. Conclusions: Patients with posterior crossbites have increased face height and different patterns of facial proportions compared with individuals without crossbites.

A Correlation Analysis between Arch Width and Molar Inclination Using Cone-Beam Computed Tomography Transverse Measurements: A Cross-Sectional Study

A new era in 3-dimensional analysis has begun with the use of cone-beam computed tomography (CBCT) in orthodontics, which promises to provide a more thorough understanding of the craniofacial skeletal architecture. This study aimed to investigate the correlation between the transverse basal arches discrepancy and dental compensation by utilizing CBCT width analysis. An observational study was conducted to retrospectively review 88 CBCT scans of patients presented to dental clinics from 2014 to 2020 obtained from the Planmeca Romexis x-ray system at three centers. Dental compensation data across normal and narrow maxillae were analyzed and a Pearson correlation was used to find the relationship between molar inclination and width difference. Significant maxillary molar compensation differences were observed between the normal maxilla and narrow maxilla group, where the amount of dental compensation (164.73 ± 10.15) was higher in the narrow maxilla group. A significant negative correlation (r = -0.37) was observed between width difference and maxillary molar inclination. Maxillary molars were tipped buccally to compensate for the reduced maxillary arch width. These findings are important to determine the amount of needed maxillary expansion taking into account the buccal inclination while treating cases.

Transverse growth of the mandibular body in untreated children: a longitudinal CBCT study

OBJECTIVES

Currently available reports on mandibular transverse growth are limited to two-dimensional images and cross-sectional studies. The objective of this study was to examine transverse growth of the mandibular body in untreated growing individuals during the mixed dentition stage using longitudinal three-dimensional imaging.

METHODS

CBCT images of 25 (13 females and 12 males) untreated subjects at two time points were analyzed. The average age was 9.1 years at T1 and 11.3 years at T2. Mandibular segmentation and superimposition were performed to obtain linear and angular measurements at different axial levels.

RESULTS

At the superior (mental foramen) axial level, transverse growth between the buccal surfaces gradually increased from the premolars to the ramus. At the inferior axial level, significant transverse growth differences were detected between the ramus and the dentition regions. In contrast, between the lingual surfaces, both superior and inferior levels showed minimal change in the region under the dentition and a significant amount of resorption in the ramus region. This difference between buccal and lingual surface changes led to a mandibular body angulation change in the premolar and molar regions. In contrast, the overall mandibular body angulation measured from the posterior-most border of the mandible to the symphysis remained the same. Differences were detected between males and females, with males tending to exhibit greater transverse growth in the ramus region at the inferior level.

CONCLUSIONS

The mandibular body exhibited different transverse growth patterns at different axial levels. Differences were also found between genders.

CLINICAL RELEVANCE

An in-depth understanding of craniofacial growth and development is crucial to diagnosis and treatment planning. The current study provides additional insight into the transverse growth of the mandible.

Transverse Growth of the Maxillo-Mandibular Complex in Untreated Children: A Longitudinal Cone Beam Computed Tomography Study

The aim of this study is to evaluate the longitudinal transverse growth of the maxillo-mandibular complex in untreated children using the Cone Beam Computed Tomography (CBCT). Two sets of scans on 12 males (mean 8.75 years at T1 and 11.52 years at T2) and 18 females (mean 9.09 years at T1 and 10.80 years at T2) were analyzed using Dolphin 3D imaging. The transverse widths of various maxillary and mandibular skeletal landmarks and the dentoalveolar and dental landmarks at the level of first molars were measured. Overall, there were greater increases in the transverse dimension in the posterior than anterior portions of the maxilla and mandible. The increase in intergonial width of the mandible seems to be primarily due to the lengthening of the mandibular body. The dentoalveolar process at the first molar level increases at an equal rate corono-apically and is independent to the changes in molar inclination. When comparing maxillary dentoalveolar changes with that of the mandible, greater increases were noticed in the maxilla, which might be explained by the presence of sutural growth in the maxilla. Moreover, the first molars maintain their coordination with each other despite the differential increase in the maxillary and mandibular dentoalveolar processes.

Surgical Treatment Selection in Adult Class III Patients With Maxillary Transverse Deficiency

The purpose of this study was to investigate the frequency of three commonly used treatments for skeletal class III malocclusion with maxillary transverse deficiency (MTD) (SCM) patients in East Asian, to find a quantitative method for precise discrepancy evaluation, and to find other potential indicators for treatment selection. A total of 239 adult SCM patients were divided into3 groups according to treatments.Dentofacial features were measured and the initial skeletal discrepancy was evaluated with computer-aided surgical simulation (CASS). Relationship between the degree of skeletal transverse discrepancy (STD) and other dentofacial features were analyzed by Spearman's rank correlation. The STD in East Asian could be quantitatively grouped as: mild (<4 mm), moderate (4-8 mm), and severe (>8 mm). Most patients (81%) could be diagnosed with mild STD, and were treated without surgical expansion. The upper first molars inclination, the required relative movement and the required maxillary movement were correlated to the degree of STD. The conventional orthodontic and orthognathic treatment without surgical expansion is the most frequent choice for East Asian SCM adults. CASS facilitated analysis is useful in an accurate MTD evaluation. Some dentofacial features were closely correlated to STD, and thus were helpful for the treatment selection.

Comparison of changes in the transverse dental axis between patients with skeletal Class III malocclusion and facial asymmetry treated by orthognathic surgery with and without presurgical orthodontic treatment

Objective

To evaluate transverse skeletal and dental changes, including those in the buccolingual dental axis, between patients with skeletal Class III malocclusion and facial asymmetry after bilateral intraoral vertical ramus osteotomy with and without presurgical orthodontic treatment.

Methods

This retrospective study included 29 patients with skeletal Class III malocclusion and facial asymmetry including menton deviation > 4 mm from the midsagittal plane. To evaluate changes in transverse skeletal and dental variables (i.e., buccolingual inclination of the upper and lower canines and first molars), the data for 16 patients who underwent conventional orthognathic surgery (CS) were compared with those for 13 patients who underwent preorthodontic orthognathic surgery (POGS), using three-dimensional computed tomography at initial examination, 1 month before surgery, and at 7 days and 1 year after surgery.

Results

The 1-year postsurgical examination revealed no significant changes in the postoperative transverse dental axis in the CS group. In the POGS group, the upper first molar inclined lingually on both sides (deviated side, −1.8° ± 2.8°, p = 0.044; nondeviated side, −3.7° ± 3.3°, p = 0.001) and the lower canine inclined lingually on the nondeviated side (4.0° ± 5.4°, p = 0.022) during postsurgical orthodontic treatment. There were no significant differences in the skeletal and dental variables between the two groups at 1 year after surgery.

Conclusions

POGS may be a clinically acceptable alternative to CS as a treatment to achieve stable transverse axes of the dentition in both arches in patients with skeletal Class III malocclusion and facial asymmetry.

[Midpalatal cortex osteotomy assisted rapid maxillary expansion for correction of maxillary transverse deficiency in young adults]

Objective: To evaluate the application of midpalatal cortex osteotomy assisted rapid maxillary expansion for correction of maxillary transverse deficiency in young adults. Methods: Fourteen young adult patients with maxillary transverse deficiency were treated with midpalatal cortex osteotomy assisted rapid maxillary expansion. Lateral cephalogram and cone beam CT (CBCT) were taken before and 3 months after treatment. The width of basal bone, arch of maxilla and the torque of anchorage teeth were compared before and after treatment. Results: The width of dental arch of maxilla was increased from 40.54±5.26 mm before treatment to 46.83±5.83 mm after treatment (P<0.05) and the width of basal bone was increased from 64.86±4.16 mm to 67.60±4.66 mm (P<0.05) at the plane of the maxillary first molars. Accordingly, the width of dental arch of maxilla was increased from 31.92±2.55 mm to 38.65±3.14 mm (P<0.05) and the width of basal bone was increased from 43.33±3.70 mm to 45.78±4.57 mm (P<0.05) at the plane of first premolar. And the torque of maxillary anchorage teeth were increased (P<0.05). Conclusion: Midpalatal cortex osteotomy assisted rapid maxillary expansion is an effective micro-invasive method in expansion of basal bone and arch of maxilla for young adult patients with maxillary transverse deficiency.

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

OBJECTIVE

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Diagnostic methods for assessing maxillary skeletal and dental transverse deficiencies: A systematic review

Objective

To evaluate the accuracy and reliability of the diagnostic tools available for assessing maxillary transverse deficiencies.

Methods

An electronic search of three databases was performed from their date of establishment to April 2015, with manual searching of reference lists of relevant articles. Articles were considered for inclusion if they reported the accuracy or reliability of a diagnostic method or evaluation technique for maxillary transverse dimensions in mixed or permanent dentitions. Risk of bias was assessed in the included articles, using the Quality Assessment of Diagnostic Accuracy Studies tool-2.

Results

Nine articles were selected. The studies were heterogeneous, with moderate to low methodological quality, and all had a high risk of bias. Four suggested that the use of arch width prediction indices with dental cast measurements is unreliable for use in diagnosis. Frontal cephalograms derived from cone-beam computed tomography (CBCT) images were reportedly more reliable for assessing intermaxillary transverse discrepancies than posteroanterior cephalograms. Two studies proposed new three-dimensional transverse analyses with CBCT images that were reportedly reliable, but have not been validated for clinical sensitivity or specificity. No studies reported sensitivity, specificity, positive or negative predictive values or likelihood ratios, or ROC curves of the methods for the diagnosis of transverse deficiencies.

Conclusions

Current evidence does not enable solid conclusions to be drawn, owing to a lack of reliable high quality diagnostic studies evaluating maxillary transverse deficiencies. CBCT images are reportedly more reliable for diagnosis, but further validation is required to confirm CBCT's accuracy and diagnostic superiority.