Association between mandibular posterior alveolar morphology and growth pattern in a Chinese population with normal occlusion

Effect of breathing patterns on mandibular cortical bone quality in children and establishment of a preliminary screening model

OBJECTIVE

This retrospective study analyzed breathing patterns and age subgroups effect on cortical bone quality of the mandible in growing subjects, aiming to explore the application value of facial skeletal pattern combined with cortical bone density detection in early screening diagnosis of mouth breathing.

METHODS

One hundred twenty-six participants were divided into four groups: mouth breathing group (7-9, 10-12 years old) and nasal breathing group (7-9, 10-12 years old). The mandibular anterior, middle, and posterior cortical bone mineral density (CBMD), cortical bone width (MCW), ANB, and FMA values were measured. Independent T-test and Mann-Whitney U test were used to compare the measured values. Binary logistic regression was employed to analyze the correlation between measured variables and the children's breathing patterns. ROC analysis was used to determine the ability of the cortical bone density measurements in early screening diagnosis of MB.

RESULTS

Mouth breathing had a negative impact on CBMD and MCW of the pre-mandibular (Pog) in subjects aged 7-9 years and also impacted the development of (Pog) and submandibular (Me) sites in subjects aged 10-12 years. Older children in the nasal breathing group have higher CBMD, MCW, and SNB values and lower FMA values. Single-factor and multiple-factor logistic binary regression analysis showed that FMA, MSPogCBMD, MSPogMCW, and ANB are correlated factors for children at risk of mouth breathing.

CONCLUSION

Mouth breathing pattern is closely associated with decreased mandibular CBMD and MCW values in children aged 7-12, where the anterior (Pog) and inferior (Me) sites of anterior mandible are more significantly affected. Furthermore, in combination with facial skeletal pattern, it provides a basis for the early warning diagnosis of mouth breathing.

Three-dimensional evaluation of the cortical and cancellous bone density and thickness for miniscrew insertion: a CBCT study of interradicular area of adults with different facial growth pattern

AIM

The purpose of this study was to evaluate the effect of the density and the thickness of the cortical and the cancellous bone at selected inter-radicular areas in subjects with different facial growth patterns using cone beam computed tomography (CBCT) in order to choose the optimal area for miniscrew insertion.

MATERIALS AND METHODS

From 150 CBCT scans, 45 scans were included in the study. The subjects were categorized into three groups based on their skeletal growth pattern according to SN-GoMe angle and facial height index. Cortical and cancellous bone density and thickness were measured at the selected inter-radicular areas.

RESULTS

Compared to the other two groups, the hyperdivergent group had thinner cortical bone in the anterior region of the maxilla between the central and the lateral incisors on the buccal side at 4 mm from the alveolar crest (P-value: 0.012) and on the palatal side at 7 mm from the alveolar crest (P-value: 0.030). Cancellous bone density values in these areas were higher in subjects with hypodivergent and hyperdivergent growth pattern. Furthermore, in hyperdivergent group less dense cortical bone in the posterior region of the maxilla on the palatal side between the second premolar and the first molar (p-value: 0.020) and on the buccal side between the first molar and the second molar (p-value: 0.038 & 0.047) was observed. No significant differences were found in the mandible between the three groups. No significant differences were found between the male and the female subjects.

CONCLUSION

Hyperdivegents presented thinner cortical bone in the anterior of the maxilla between the central and the lateral incisors. Less dense cortical bone was found between maxillary second premolar and first molar on the palatal side and also between the maxillary first molar and the second molar on the buccal side in this group too. Normal showed higher density values in the posterior of the maxilla compared to the other two groups. No significant differences were found among three groups in mandible.

Comparison of invisalign mandibular advancement and twin-block on upper airway and hyoid bone position improvements for skeletal class II children: a retrospective study

BACKGROUND

This study is to evaluate and compare the improvement of upper airway morphology and hyoid bone position in children with Class II mandibular retrusion treated with Invisalign mandibular advancement (MA) and Twin-Block (TB) appliances, utilizing cone beam computed tomography (CBCT).

METHODS

32 children aged between 8 and 11.5 years old were included in this study, with an average age of 10.2 years old. These children were divided into two groups, MA and TB, with 16 children in each group. Changes in upper airway morphology and hyoid bone position before and after treatment were analyzed using CBCT.

RESULTS

(1) Changes in upper airway before and after treatment: the oropharynx volume (Or-V), the oropharynx minimum cross-sectional area (Or-mCSA), the hypopharynx volume (Hy-V), and the hypopharynx minimum cross-sectional area (Hy-mCSA) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05) compared to pre-treatment status. (2) Changes in hyoid bone position before and after treatment: The distances between H point and third cervical vertebra (H-C3), H point and pogonion (H-RGN), H point and mandibular plane (H-MP), H point and Frankfort horizontal plane (H-FH), H and S point (H-S), and H point and palatal plane (H-PP) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05).

CONCLUSION

Both MA and TB appliances effectively improved the structural narrowness of the upper airway and reduced respiratory resistance, thus improving breath quality. However, MA showed more effectiveness in improving the narrowest part of the hypopharynx compared to TB. Both appliances also promoted anterior downward movement of the hyoid bone, which opens the upper airway of the oropharynx and hypopharynx and helps the upper airway morphology return to normal range.

Characteristics of Spatial Changes in Molars and Alveolar Bone Resorption among Patients with Loss of Mandibular First Molars: A CBCT-Based Morphometric Study

OBJECTIVES

To investigate the characteristics of spatial changes in molars and alveolar bone resorption among patients with loss of mandibular first molars.

METHODS

A total of 42 CBCT scans of patients with missing mandibular first molars (3 males, 33 females) and 42 CBCT scans of control subjects without loss of mandibular first molars (9 males, 27 females) were evaluated in this cross-sectional study. All images were standardized using the mandibular posterior tooth plane with Invivo software. The following indices regarding alveolar bone morphology were measured, including alveolar bone height, bone width, mesiodistal and buccolingual angulation of molars, overeruption of maxillary first molars, bone defects, and the capability of molar mesialization.

RESULTS

The vertical alveolar bone height in the missing group was reduced by 1.42 ± 0.70 mm, 1.31 ± 0.68, and 1.46 ± 0.85 mm on the buccal, middle, and lingual side, respectively (no differences among the three sides; p > 0.05). Alveolar bone width was reduced the greatest at the buccal CEJ level and the least at the lingual apex level. Mandibular second molar mesial tipping (with mean of the mesiodistal angulation = 57.47 ± 10.34°) and lingual tipping (with mean of the buccolingual angulation = 71.75 ± 8.34°) were observed. The mesial and distal cusps of maxillary first molars were extruded by 1.37 mm and 0.85 mm, respectively. Buccal and lingual defects of alveolar bone occurred at the CEJ, mid-root, and apex levels. Through 3D simulation, the second molar cannot be successfully mesialized into the missing tooth position, and the difference between the available and required distances for mesialization was the greatest at the CEJ level. The duration of tooth loss was significantly correlated with the mesio-distal angulation (R = -0.726, p < 0.001), buccal-lingual angulation (R = -0.528, p < 0.001) and the extrusion of the maxillary first molar (R = -0.334, p < 0.05).

CONCLUSION

Both vertical and horizontal resorption of alveolar bone occurred. Mandibular second molars exhibit mesial and lingual tipping. Lingual root torque and uprighting of the second molars are needed for the success of molar protraction. Bone augmentation is indicated for severely resorbed alveolar bone.

The Relationship Between Vertical Facial Type and Maxillary Anterior Alveolar Angle in Adults Using Cone-Beam Computed Tomography

Background

Cone-beam computed tomography (CBCT) imaging provides detailed and thorough information about the dentofacial complex. However, not all aspects have been yet explored among different types of malocclusion. The maxillary anterior alveolus is one of the components of the maxillary bone which affects the upper lip position and the esthetics of the smile. The inclination of this alveolus may vary between the different vertical growth patterns of patients who may seek orthodontic treatment. The objective of this study was to investigate possible differences in maxillary anterior alveolar angle (MAAA) among orthodontically untreated adults with different vertical facial types in a Syrian sample.

Methods

CBCT images of 84 orthodontically untreated adult patients were included. Three groups of vertical facial type (n=28 for each group; 14 males, 14 females) were created using disproportionate multi-stratified random sampling. CBCT-derived lateral cephalograms were used to categorize the patients into three groups. Measurements were made at three regions (region 1 (R1), region 2 (R2), and region 3 (R3)), located in the maxillary anterior alveolar bone using OnDemand3D™ software (Cypermed Inc., Seoul, South Korea).

Results

No significant differences in the mean MAAA were detected between females and males for the three measured regions in all groups. Analysis of variance showed significant inter-group differences in the MAAA (p<0.05) for all measured regions. The hyperdivergent facial type group had the greatest MAAA mean value of 68.72° (± 6.01), 67.30° (± 4.15), and 68.01° (± 5.12) at R1 in the female, male, and the entire sample of both sexes respectively. Whereas the hypodivergent facial type group had the least mean MAAA values of 58.47° (± 5.34) at R3, 59.83° (± 6.23) at R2, and 59.23° (± 5.75) at R3 in the female, male, and the entire sample of both sexes respectively.

Conclusions

The maxillary anterior alveolar bone was more buccally inclined in the hypodivergent facial type. The MAA bone inclination did not differ between females and males in the same vertical facial type group.

Three-dimensional evaluation of hyoid bone position in nasal and mouth breathing subjects with skeletal Class I, and Class II

BACKGROUND

This retrospective study investigated the effect of breathing pattern, skeletal class (Class I, Class II), and age on the hyoid bone position (HBP) in normodivergent subjects.

METHODS

A total of 126 subjects (61 males, 65 females) aged 7-9 years and 10-12 years were scanned using cone-beam computed tomography (CBCT). All participants were classified according to the anteroposterior skeletal pattern into (Class I, Class II). Each skeletal group was further divided according to the breathing mode into mouth breathers (MB) and nasal breathers (NB). The HBP was measured accordingly. Independent sample t-test and Mann Whitney U test were used to detect significant differences between the groups, and binary logistic regression was used to identify MB predictive indicators.

RESULTS

The breathing mode and skeletal class affected the vertical HBP in subjects with 7-9 years, while they affected the anteroposterior HBP in subjects with 10-12 years. Regarding the age effect, hyoid bone was located more anteriorly in the older NB subjects, and hyoid bone was more inferiorly in the older age group. A regression equation of the significant variables was formulated, C3-Me (P: 001, OR: 2.27), and H-EB (P: 0.046, OR: 1.16) were positively correlated with occurrence of MB.

CONCLUSION

There were significantly different HBPs among subjects with different anteroposterior skeletal classes, breathing modes, and age cohorts. Moreover, C3-Me, and H-EB were significant predictors and correlated with increased likelihood of being MB subject.

Buccal Bone Thickness in Anterior and Posterior Teeth-A Systematic Review

(1) Background: Immediate dental implant placement has been a subject of great interest over the last decade. Here, information regarding the anatomy and bone thickness of the jaw prior to dental implant placement is crucial to increase the surgery's success and the patient's safety. The clinical premises for this approach have been controversially discussed. One of those heavily discussed premises is a buccal bone thickness of at least 1 mm thickness. This meta-analysis aims to systematically review buccal bone thickness (BBT) in healthy patients. Thus, the feasibility of immediate dental implant placement in daily practice can be assessed. (2) Methods: A search in the electronic databases was performed to identify articles reporting on BBT that was measured by computed tomography in adults. (3) Results: We were able to find 45 studies, including 4324 patients with 25,452 analyzed teeth. The analysis showed a BBT at the alveolar crest of 0.76 ± 0.49 mm in the maxillary frontal and of 1.42 ± 0.74 mm in the maxillary posterior region. In the mandible, the average measured values were similar to those in the maxilla (front: 0.95 ± 0.58 mm; posterior: 1.20 ± 0.96 mm). In the maxillary frontal region 74.4% and in the mandibular frontal region 61.2% of the crestal buccal bones showed widths <1 mm. (4) Conclusions: In more than 60% of the cases, the BBT at the alveolar crest is <1 mm in maxillary and mandibular frontal regions. This anatomic data supports careful pre-surgical assessment, planning of a buccal graft, and critical selection of indication for immediate implant placement, especially in the maxillary and mandibular frontal and premolar region.

Variability associated with mandibular buccal shelf area width and height in subjects with different growth pattern, sex, and growth status

INTRODUCTION

The primary objective of the study was to quantitatively analyze the width and height of the mandibular buccal shelf area (MBS) at 3 different potential locations for mini-implant placement. In addition, we aimed to compare and contrast the bone parameters of the MBS to study the correlation between different growth status (growing or nongrowing), facial types (hypodivergent, normodivergent, and hyperdivergent), and sex differences (male or female).

METHODS

In this retrospective cone-beam computed tomography study, 678 subjects were included. They were divided into groups according to growth status, facial type, and sex. Scans were imported into the reconstruction program and were aligned in 3 different steps. Measurements were made at 6 different coronal sections: mandibular first molar distal root, second molar mesial root, and second molar distal root (bilaterally). The roots of mandibular molars were used as a reference to measure the width and the roof of the inferior alveolar canal to measure the height of the buccal shelf area. Intraobserver reliability was assessed by measuring the width and height of MBS in 20 randomly selected subjects.

RESULTS

No significant difference (P > 0.05) was found in the width of MBS between males and females. MBS width increased, and height decreased (P < 0.0001) as moved distally from the first molar distal root to the second molar distal root in all 3 facial types irrespective of age or sex. The hypodivergent facial type had significantly greater bone width than the hyperdivergent facial type at all the 3 locations in both males and females. The hypodivergent facial type had significantly less (P < 0.0001) bone height than the hyperdivergent group at all the 3 locations irrespective of age or sex.

CONCLUSIONS

The optimal site for MBS mini-implant is the buccal region of the distal root of mandibular second molars. Hypodivergent patients have more width and less height of MBS compared with hyperdivergent patients. MBS mini-implants are not advised for growing patients because of proximity to developing roots.

Facial Growth Patterns and Insertion Sites of Miniscrew Implants

INTRODUCTION

We aimed to evaluate the associations between the craniofacial growth pattern with interradicular distances (IRDs), cortical widths (CWs), and jaw heights (JHs). Also, we mapped safe zones for miniscrew implantation.

METHODS

Cone-beam computerized tomography data pertaining to 60 Class-I patients were divided into 3 growth groups: normal, horizontal, and vertical. IRDs and CWs were measured for bimaxillary canines to second molars, on buccal and lingual sides, at 3 transverse planes (1, 3, and 5 mm apically to the alveolar crest). JHs were measured in both jaws, between canines and second molars. The role of growth patterns and other variables were analyzed; also, safe zones were mapped with statistical substantiation.

RESULTS

IRDs were greater in the mandible, males, at points more distant from the ridge crest, and on the lingual side. Cortexes were thicker in the horizontal growth pattern, mandible, males, older patients, and lingual sides. JHs were greater in vertical growth pattern, mandible, and males.

CONCLUSIONS

The cortex might be thicker in patients with a horizontal growth pattern. The height might be greater in vertical growth pattern. IRDs might not be affected by growth pattern.

Alveolar bone mapping in subjects with different vertical facial dimensions

OBJECTIVE

The purpose of this study was to investigate differences in alveolar and skeletal dimensions among subjects with different vertical facial dimensions using cone beam computed tomography (CBCT). To date, this is the first study that investigates the relationship between facial type and posterior alveolar thickness in both maxilla and mandible, using CBCT data.

MATERIALS AND METHODS

From a sample of 152 CBCT scans, 45 scans were selected to be included in the study. CBCT-synthesized lateral cephalograms were used to categorize subjects into three groups based on their vertical skeletal pattern. Using iCATVision™ software, measurements of alveolar height and thickness were carried out in the entire tooth-bearing region. In addition, AutoCAD™ software was used to carry out measurements for the anatomical limitation to labio-lingual incisor movement. Kruskal-Wallis and Mann-Whitney U-tests with the Bonferroni adjustment were done for statistical analyses.

RESULTS

Compared to the other two groups, high-angle group had larger anterior dentoalveolar height with no significant differences in alveolar height posteriorly, in both the maxilla and mandible. Furthermore, high-angle group presented thinner alveolus anteriorly in the maxilla and at almost all sites in the mandible. Low-angle group had higher mean values for some measurements of the anatomical limitation to labio-lingual incisor movement for all upper and lower incisors.

LIMITATIONS

Inherent limitations of CBCT scanning as related to physical spatial resolution of the image and limitations posed by the study sample size should be considered.

CONCLUSIONS

There is a statistically significant relationship between facial type and alveolar height and thickness. High-angle subjects can be at increased risk of moving incisors beyond alveolar bone support when subjected to marked antero-posterior incisor movement.