A CBCT based analysis of the correlation between volumetric morphology of the frontal sinuses and the facial growth pattern in caucasian subjects. A cross-sectional study

BACKGROUND

The aim of this study was to evaluate the relationship between frontal sinus shape and facial growth pattern.

METHODS

The three-dimensional examination was carried out by means of 80 CBCT scans selected from a sample of 1247 records of patients treated, for different reason, at the Department of Biomedical Surgical and Dental Sciences at University of Milan, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico Milan. The sample (age ranges between 12 and 40 years) was divided according to gender and age in four groups (12-17, 18-20, 21-30, 31-40). Left and right frontal sinus volume (VOL), surface (SUP) and linear maximum width (XMAX), depth (ZMAX) and height (YMAX) were calculated using Mimics Research 17.0 (Materialise N.V., Leuven, Belgium). Cephalometric analysis has been performed for all subjects to categorize the patients depending on their facial growth pattern. Univariate and multivariate regression analysis were performed to investigate any association of frontal sinuses measurements (height, width, depth, volume and surface) and cephalometric variables. P value < 0.05 was considered statistically significant.

RESULTS

A total of 160 frontal sinuses were measures in 80 patients: 40 men and 40 women, average age of 23.5 ±14.6. Globally the frontal sinuses had the following average dimensions: volumes of 9055.8 ± 6505 mm3 and surfaces of 3820.3 ± 2125 mm2. The statistical analysis showed that frontal sinus volume was statistically significant (p=0.003) greater for male (11,425 mm3) than female (6597.5 mm3). Similarly, the surface showed to be greater in men than in women (p=0.005). No correlation between age and frontal sinuses characteristics has been found. A statistically significant (p<0.05) increase of frontal sinus depth, surface and volume was correlated with SNB angle. In addition, frontal sinus volume increased in subjects with greater anterior skeletal dimension values and with a superior length of the cranial base. Furthermore, a decrease of ANB has been found related to an increase in frontal sinus volume (p=0.04).

CONCLUSIONS

The present study showed a correlation between frontal sinuses dimensions and craniofacial aspects, despite the inter-individual variability of their morphology. The results suggested that young adults in whom the frontal sinuses have reached their maximum size, while vertical growth continues, a larger frontal sinus may be associated with future vertical growth.

Correlation between facial growth patterns and cortical bone thickness assessed with cone-beam computed tomography in young adult untreated patients

Background

The vertical facial growth pattern is one of the most important issue in the orthodontic diagnosis and treatment. Previous studies investigated the association between interdental bone thickness and facial divergence using mainly bidimensional analysis. When two-dimensional dental radiographic views are not sufficient for diagnosis and measurements, cone-beam computed tomography (CBCT) images should be used to assess the alveolar bone structure three-dimensionally and with high accuracy and reliability.

The aim of the present study was to evaluate the correlation between alveolar bone thickness and facial divergence in young adults untreated patients using a three-dimensional method analysis with CBCT images.

Methods

Records of 30 untreated patients (mean age 16 ± 2 years) with Angle Class I and mild to moderate crowding were analyzed. Subjects were classified as hypodivergent (<39˚), normodivergent (41 ± 2˚), and hyperdivergent (>43°). according to the inter-maxillary angle between the sagittal maxillary plane (ANS-PNS) and the mandibular plane (GN-ME). The alveolar bone thickness measurements were taken for the buccal and palatal/lingual surfaces of maxillary and mandibular anterior teeth. Axial-guided navigation (AGN) was used to locate all landmarks using a specific software (Horos 3.0).

Results

The statistical analysis showed a significant difference between the hypodivergent and hyperdivergent group regarding buccal bone height (P = 0.005), buccal apical bone thickness (P = 0.003) and palatal mid-root bone thickness (P = 0.006). Moreover, buccal bone height (P = 0.006) was found to be statistically significant different in normodivergent compared with hypodivergent individuals.

Conclusions

Facial types were found to be correlated with alveolar bone thickness. The hyperdivergent subjects presented thinner alveolus bone in the anterior maxilla and at almost all sites in the mandible. Clinicians should be aware of the possibility of thin cortical bone plates in hyperdivergent patients, reducing antero-posterior movements to avoid fenestration and dehiscence.

Upper and lower pharyngeal airway space in West-Tamil Nadu population

Aim:

To compare the upper and lower pharyngeal airway (LPA) width in Class II malocclusion patients with low, average, and high vertical growth patterns.

Study Design:

Cross-sectional analytical study.

Materials and Methods:

Pretreatment lateral cephalometric films of 90 Class II subjects were used to measure the upper and LPAs. The inclusion criteria were subjects of West-Tamil Nadu, aged between 14 and 25 years, only skeletal Class II subjects of either gender and no pharyngeal pathology at initial visit. The sample comprised a total of 90 Class II subjects divided into three groups according to the vertical facial pattern: Normodivergent (n = 30), hypodivergent (n = 30), and hyperdivergent (n = 30). The assessment of upper and LPAs was done according to McNamara's airway analysis.

Statistical Analysis:

The intergroup comparison of the upper and LPAs was performed with one-way analysis of variance and the Tukey test was used to compare among the various vertical patterns.

Results:

Skeletal Class II subjects with hyperdivergent facial pattern showed statistically significant narrow upper pharyngeal width when compared to normodivergent and hypodivergent facial patterns. No statistically significant difference was found in the lower pharyngeal width in all three vertical facial growth patterns.

Conclusion:

Subjects with Class II malocclusions and hyperdivergent growth pattern have significantly narrow upper pharyngeal airway space when compared to other two vertical patterns. Narrow pharyngeal airway space is one of the predisposing factors for mouth breathing and obstructive sleep apnea.

'Comparison and correlation of the maxillary sinus dimensions in various craniofacial patterns: A CBCT Study'

Background: To compare and correlate the maxillary sinus dimensions and basal bone height among various facial patterns using CBCT for advanced diagnosis and treatment planning in Orthodontics.

Methods: 66 CBCT images within age group of 18-30 years were divided into horizontal (Group 1), average (Group 2) and vertical (Group 3) facial growth patterns. Maxillary sinus dimensions were compared and correlated in all three groups. The sinus height and basal bone height were recorded at 3 locations-between 1 ^st premolar and 2 ^nd premolar (PM1-PM2), between 2 ^nd premolar and 1 ^st Molar (PM2-M1) and between 1 ^st and 2 ^nd molar (M1-M2).

Results: Overall reduction in sinus height and significantly reduced sinus volume was seen in Group-1. Longest maxillary sinus height in M1-M2 region and shortest in PM1-PM2 region was seen in Group-3. The basal bone height in PM1-PM2 region was significantly longer in Group-3 than in Group-1(p<.05).Shortest basal bone height in M1-M2 region was seen in Group-3. A significant negative correlation was seen between the maxillary sinus height and the basal bone height in Group-1 and Group-3(p<.05).

Conclusion: There is a correlation between the maxillary sinus height and basal bone height with that of facial pattern which needs to be considered during orthodontic treatment planning and while carrying out facial growth modification procedures in younger patients.

Comparison of mesiodistal angulations of premolars and molars in anterior open bite subjects with different sagittal malocclusions: A retrospective study

INTRODUCTION

Mesiodistal angulation of premolars and molars can be altered by forces of open bite malocclusion. The aim of this study was to compare the mesiodistal angulations of the posterior teeth in class I, II, and III individuals with anterior open bite (AOB) versus individuals with harmonious occlusion.

METHODS

This comparative cross-sectional study used 299 lateral head radiographs of individuals with permanent dentition. There were 4 groups (harmonious occlusion [n=89], Class I open bite [OB] [n=75], Class II OB [n=66], and Class III OB [n=69]). Premolar (1UPM, 2UPM) and molar (1UM, 2UM) angulations were measured relative to the occlusal plane and the palatal or mandibular plane by a trained and calibrated evaluator. ANOVA and Scheffe tests were used for statistical analyses (P<0.05).

RESULTS

The mesial angulation of the upper premolars showed greater angulation of between approximately 2° and 5° in the OB groups compared to the harmonious occlusion group (P<0.05). Only in the Class II OB group did the first and second upper molars show distal angulation in relation to the palatal plane (1UM 81.85°±5.42°; 2UM 75.32±7.4°) (P<0.05). The Class III OB group presented the greatest distal angulations of the lower premolars and molars (between 3° to 5° of difference, P<0.05) in relation to those of the harmonious occlusion group.

CONCLUSIONS

The upper first premolars in all the AOB groups and the lower second premolars in the Class II OB group had greater mesioangulation. Additionally, the upper molars of the Class II OB group and the lower molars of the Class III OB group showed distoangulation compared with the molars in the group with harmonious occlusion.

Reliability of Zagreb 82 MOD Cephalometric Assessment in Determining the Facial Growth Pattern

Objective

The aim of this study was to investigate accuracy and reliability of the existing cephalometric analysis Zagreb82 MOD in determining the facial growth pattern.

Materials and methods

Of all patients aged 10-17 years without missing teeth, craniofacial anomalies and previous orthodontic medical history, who were attending Department of Orthodontics, University Hospital Centre Zagreb in years 2021 and 2022, lateral cephalograms were examined. Subsequently, subjects were collected and divided into two groups: eugnathic group (N=50, SNA 81°±3.5°, SNB 78.5°±3°, ANB 2.5°±2°, Wits -1±2mm, Angle class. I, overbite 1-3.5mm, overjet 1-3.5mm, dystopia<3mm, total crowding<3mm, total diastemas<3mm) and test group (N=129, overbite>4mm for deep bite and overbite<-0.1mm for open bite). In the eugnathic group, reference values were calculated for ten skeletal parameters and a corrected analysis was created. In the test group, facial growth patterns (horizontal, neutral or vertical) were determined, within the corrected and Zagreb82 MOD analysis. The T-test was used to examine the differences between the corrected and the Zagreb82 MOD analysis. The McNemar test was performed to compare the distribution of facial growth patterns between the tested parameters within and between analyses.

Results

Differences were observed in the reference values of saddle angle, Y-axis, articular angle, mandibular angle, Björk's Sum and upper section of mandibular angle (p<.05). The distribution of facial growth patterns according to Y-axis, intermaxillary angle, mandibular angle, Bjork's Sum also differed between the two analyzes (p<.001). In the corrected values analysis, there was no significant difference in the distribution of facial growth patterns between Björk's Sum, mandibular inclination, and intermaxillary angle (p>.05).

Conclusion

The reliability of Zagreb82 MOD analysis in defining facial growth pattern should be taken with caution. Björk's Sum, intermaxillary angle and inclination of mandible are equitable parameters in determining the facial growth pattern within the corrected analysis.