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

Lower incisor position in skeletal Class III malocclusion patients: a comparative study of orthodontic camouflage and orthognathic surgery

OBJECTIVES

To determine the difference between orthodontic camouflage and orthodontic-orthognathic surgery using the traditional cephalometric measurement IMPA and the newly proposed IA/PAMD, the angle between the long axis of the lower incisor (IA) and the principal axis of the mandibular alveolus (PAMD).

MATERIALS AND METHODS

This study included 40 cases each in the orthodontic camouflage group (OG) and orthodontic-orthognathic surgery group (SG). The differences between the IMPA and IA/PAMD before and after treatment were compared between the two groups. T0 lateral cephalometric images of the 10 cases with the highest and lowest increase in the IA/PAMD were analyzed to identify characteristics associated with a higher risk of overdecompensation of the lower incisors during presurgical orthodontic treatment.

RESULTS

Both the OG and SG showed a significant improvement in hard- and soft-tissue measurements. However, in the OG, there was significant lingual inclination of the lower incisor but only a small change in the IA/PAMD. In the surgical group, the IMPA was close to 90° after treatment, but the IA/PAMD significantly increased.

CONCLUSIONS

In orthodontic camouflage, the lower anterior teeth were significantly moved lingually with a better root-bone relationship. However, this relationship deteriorated in some surgical patients. Therefore, it is important to conduct cephalometric or cone-beam computed tomography examinations during preoperative orthodontics to identify and prevent possible periodontal risks.

Orthodontic camouflage treatment for a patient with bilateral cleft lip and palate, bilateral crossbite, and microdontic maxillary lateral incisors

Cleft lip and palate is a congenital craniofacial anomaly that affects the lip and oral cavity. The management and orthodontic treatment of this anomaly is important but challenging. This article reports the successful treatment of a patient with bilateral cleft lip and palate, Class III malocclusion, bilateral crossbite, crowding and microdontic maxillary lateral incisors. One mandible incisor was extracted, and three miniscrew anchorages were utilized to distalize the maxillary left dental arch and retract the mandibular arch. After treatment, ideal occlusion and a better profile were established, and long-term stability was confirmed by a 4-year follow-up. This article represents a successful attempt of orthodontic camouflage treatment of severe dentofacial discrepancy, as an important part of the series treatment of cleft lip and palate, to provide some insight into the clinical field.

Mandibular alveolar bone thickness in untreated Class I subjects with different vertical skeletal patterns: a cone-beam computed tomography study

OBJECTIVE

To evaluate the mandibular alveolar bone thickness in untreated skeletal Class I subjects with different vertical skeletal patterns.

MATERIALS AND METHODS

A total of 50 preorthodontic treatment cone-beam computed tomography (CBCT) images of a skeletal Class I Chinese population with near-normal occlusion were selected. The buccal and lingual alveolar bone thicknesses of mandibular canines to second molars were measured at 2 mm below the cementoenamel junction (CEJ), mid-root, and root apex levels. Differences in the measurements were analyzed with Mann-Whitney U-test. The correlation between alveolar bone thickness and the sella-nasion-mandibular plane (SN-MP) angle was calculated using Pearson correlation coefficients and linear regression analysis.

RESULTS

Buccal alveolar bone was thinner on all mandibular canines to first molars but thicker on second molars in comparison with lingual alveolar bone. Buccal alveolar bone was within 1 mm at the levels of 2 mm below CEJ and mid-root for the canines and first premolars. Significant differences were detected among subjects with different vertical patterns, with a negative correlation between the SN-MP angle and alveolar thickness, especially in the canine and premolar regions. The thinnest buccal and lingual alveolar bone were detected in the high-angle group canine region (0.50 mm at the levels of 2 mm below CEJ and mid-root for the buccal side, 0.90 mm at the level of 2 mm below the CEJ for the lingual side).

CONCLUSIONS

To avoid periodontal complications, buccal-lingual movement of the mandibular canines and first premolars should be limited, especially in high-angle patients.

Three-dimensional evaluation of alveolar bone and pharyngeal airway dimensions after mandibular dentition distalization in patients with Class III malocclusion: a retrospective study

BACKGROUND

To three-dimensionally evaluate changes of the alveolar bone around the mandibular anterior teeth and pharyngeal airway dimensions in adults with Class III malocclusion before and after orthodontic treatment of mandibular dentition distalization.

METHODS

In this retrospective study, cone-beam computed tomography (CBCT) scans of 20 patients with Class III malocclusion who underwent mandibular dentition distalization were obtained both before and after treatment. Three-dimensional changes of the thickness and vertical marginal bone levels around mandibular incisors and canines were assessed and compared. And airway volumes of the palato-, glosso-, laryngopharynx and the minimum axial area were measured and compared before and after treatment.

RESULTS

A significant decrease of lingual bone thickness of mandibular incisors, partial labial and lingual bone thickness of canines were observed (P < 0.05). The reduction in root length of incisors and canines, labial and lingual vertical marginal bone levels were significant after orthodontic treatment. No significant correlations between mandibular dentition distalization and pharyngeal airway dimensions were observed.

CONCLUSIONS

Mandibular dentition distalization could result in the loss of alveolar bone around anterior teeth in Class III malocclusion, especially for the cervical marginal bone. Pharyngeal airway dimensions were not affected to a high extent after distalization.

TRIAL REGISTRATION

Retrospctively registered.

The Accuracy of Lateral Cephalogram for Measuring Alveolar Bone Thickness and Root Diameter on Mandibular Incisors

Background: The objective of the study was to ascertain whether the alveolar bone and root of the mandibular central incisor measured from cephalograms can represent the same measurements of both mandibular central and lateral incisors from CBCT. Methods: A total of 38 sets of CBCT images and cephalograms before treatment were selected for this study. Thicknesses included alveolar bone, cortical bone, and cancellous bone at the labial and lingual sides. Root diameter and total root-bone thickness were also evaluated. The measurements were performed at 3, 6, and 9 mm from the cemento-enamel junction. Heights included labial bone height and lingual bone height. All measurements were performed on cephalograms and CBCT images of the mandibular central incisor (L1CT) and mandibular lateral incisor (L2CT). The data were statistically analyzed using one-way ANOVA and Bonferroni tests (p < 0.01) to compare the cephalograms, L1CT, and L2CT. Results: The cephalograms presented thicker alveolar bone and cortical bone (labial: 0.16−0.31 mm, lingual: 0.14−0.29 mm; p < 0.001) as well as higher alveolar crest (labial: 0.46−0.48 mm, lingual: 0.38−0.39 mm; p < 0.001) than the CBCT images on both the labial and lingual sides, whereas lingual cancellous thicknesses were not significantly different (p = 0.257). The cephalograms presented greater total root-bone thicknesses than L1CT (0.19−0.30 mm; p < 0.001), whereas the cephalograms traced thinner roots than L1CT (0.18−0.23 mm; p < 0.001) and L2CT (0.39−0.59 mm; p < 0.001). Conclusion: Lateral cephalograms cannot represent both mandibular central and lateral incisor dentoalveolar thicknesses, heights, and root diameters the same as CBCT. However, the differences were less than 0.5 mm.

Association of Mandibular Posterior Anatomic Limit with Skeletal Patterns and Root Morphology Using Three-Dimensional Cone Beam Computed Tomography Comprehensive Analysis

This study aimed to clarify the relationship between the mandibular posterior anatomic limit (MPAL) and skeletal anteroposterior and vertical skeletal patterns, with consideration of factors that may be related. In total, 230 people were included: 49 Japanese, 122 Egyptian, and 59 Korean people. The MPAL was measured at 0, 2, 4, and 6 mm from the root furcation along the sagittal and cuspal lines at the distance from the distal root of the mandibular right second molar to the mandibular cortex of the lingual bone. Eight different MPALs were evaluated using multiple regression analysis with explanatory variables for anteroposterior and vertical skeletal patterns and qualitative variables for age, sex, population, the presence of third molars, number of roots, presence of C-shaped roots, and Angle malocclusion classification. The MPAL was significantly larger as the mandibular plane angle decreased. The MPAL near the root apex was significantly larger as the A-nasion-point B angle increased, and the MPAL near the root apex measured at the cuspal line was significantly larger for C-type roots. The present study showed that a C-shaped root affected the MPAL in addition to the anteroposterior and vertical skeletal patterns.

Three-dimensional measurement of periodontal support during surgical orthodontic treatment of high-angle skeletal Class III malocclusion: A retrospective study

INTRODUCTION

This study aimed to quantify the periodontal health of incisors during surgical orthodontic treatment in patients with high-angle Class III malocclusion using a cone-beam computed tomography (CBCT) 3-dimensional (3D) reconstruction technique.

METHODS

The sample consisted of 30 patients with high-angle Class III malocclusion (mean age, 20.53 ± 2.86 years). CBCT images were taken before treatment (T0), after presurgical orthodontic treatment, and after treatment (T2). In addition, 3D tooth and alveolar bone models were generated. The root surface area, periodontal ligament (PDL)_Area, and vertical bone level (VBL) around the maxillary and mandibular central incisors were measured.

RESULTS

The root surface area and PDL_Area of maxillary and mandibular central incisors decreased continuously between T0 and T2 (P <0.01). At T2, mandibular central incisors showed 38.64 ± 13.39% PDL_Area loss, and maxillary central incisors exhibited 21.13 ± 16.48% PDL_Area loss. For mandibular central incisors, the PDL_Area loss caused by VBL loss was significantly greater than that for maxillary central incisors (P <0.01) and significantly greater than the PDL_Area loss caused by root resorption (P <0.01). From T0 to T2, the lingual surface of maxillary central incisors exhibited greater VBL loss than the other 3 surfaces (P <0.01), and the labial and lingual surfaces of mandibular central incisors demonstrated greater VBL loss than proximal surfaces (P <0.01).

CONCLUSIONS

The 3D CBCT reconstruction method provides useful information regarding the periodontal defects of incisors in patients with high-angle skeletal Class III malocclusion. The PDL_Area of maxillary and mandibular central incisors decreased continuously during the treatment. Vertical alveolar bone levels at proximal surfaces appeared to be relatively stable.

The Accuracy of Lateral Cephalogram in Representing the Anterior Maxillary Dentoalveolar Position

Background: To evaluate the dentoalveolar position and root diameters of the maxillary incisors from cone beam computed tomograms (CBCT) compared with cephalometric tracings. Methods: A total of 64 sets of initial lateral cephalograms and CBCT images were enrolled. Measurements of dentoalveolar position included bone thicknesses and heights of alveolar, cortical, and cancellous bone. Root diameter and total root-bone thickness were also evaluated. All measurements were performed on cephalograms and CBCT images of the maxillary central incisor (U1CT) and maxillary lateral incisor (U2CT). The data were statistically analyzed using one-way ANOVA and Bonferroni tests (p < 0.01) to compare the cephalograms, U1CT, and U2CT. Results: The cephalograms presented thicker alveolar bone (labial: 0.20−0.67 mm, palatal: 0.41−0.60 mm; p < 0.001) and cortical bone (labial: 0.20−0.67 mm, palatal: 0.41−0.52 mm; p < 0.001) as well as higher alveolar crest (labial: 0.23−0.27 mm, palatal: 0.15−0.17 mm; p < 0.001) and cortical height (labial: 0.35−0.47 mm; p = 0.051, palatal: 0.14−0.18 mm; p < 0.001) than the CBCT images on both the labial and palatal sides, whereas palatal cancellous thickness was not significantly greater (p > 0.01). The cephalograms presented a greater total root-bone thicknesses (0.80−1.08 mm; p < 0.001), whereas the cephalograms traced thinner roots than the CBCT images (0.36−0.52 mm; p < 0.01). Conclusion: Routine lateral cephalograms are not suitable for alveolar bone evaluation in orthodontic treatment due to errors in representing dentoalveolar thicknesses and heights.

Relationship between alveolar-bone morphology at the mandibular incisors and their inclination in adults with low-angle, skeletal class III malocclusion—A retrospective CBCT study

Objective

To quantitatively study the effect of the labial inclination of the mandibular central incisors on the surrounding cortical and cancellous-bone morphology among patients with low-angle, skeletal class III malocclusion, by using cone-beam computed-tomography (CBCT) imaging.

Materials and methods

The CBCT images of 60 patients with low-angle, skeletal class III malocclusion were divided into lingual-inclination, upright, and labial-inclination groups. The height of the alveolar bone and the thickness and area of the cortical, cancellous, and total alveolar bone were measured separately on each side of the mandibular central incisors.

Results

The thickness of the labial cortical bone from 6 mm below the cementoenamel junction (CEJ) to the root apex; the thickness of the labial cancellous bone at the root apex; the total thickness of the alveolar bone at the root apex; the area of labial cortical bone; the total area of labial alveolar bone; and the height of the labial alveolar bone were highest in the labial-inclination group (all P<0.05). All these variables were positively correlated with the labial inclination of the mandibular central incisors (all P<0.05). There were no statistical differences between the groups for any of the measurements on the lingual side of the teeth (P>0.05).

Conclusion

The morphology of the alveolar bone on the labial but not the lingual side of the mandibular central incisors was statistically significantly correlated with the labial inclination of those teeth in patients with low-angle, skeletal class III malocclusion.

Ex-vivo imaging of buccal and oral periodontal bone with low-dose CBCT in porcine jaws

OBJECTIVES

New CBCT devices have been developed which can provide "low-dose CBCTs (LD-CBCT)". Aim of this study is to investigate the suitability of LD-CBCT for measurement of alveolar buccal/oral bone.

METHODS AND MATERIALS

Vestibular and oral bone loss of the teeth of seven porcine mandibles free of soft tissues were investigated by Micro-CT and three CBCT-modes: high-dose (HD), standard-dose (SD) and low-dose (LD). Radiographic measurements of bone loss (bl) and vestibular and oral bone thickness (bt) were made by two raters at 69 sites. Measurement means and differences, Intraclass correlation (ICC) and Bland-Altman plots were calculated.

RESULTS

ICCs between raters(r) concerning bl were 0.954 for HD, 0.949 for SD and 0.945 for LD; concerning bt they were 0.872 for HD, 0.845 for SD and 0.783 for LD. Means of differences of bt measurements were -0.01 mm(r1)/0.00 mm(r2) for HD, 0.04 mm(r1)/0.02 mm(r2) for SD and 0.02 mm(r1)/0.04 mm(r2) for LD; for bl measurements they were 0.06 mm(r1)/0.05 mm(r2) for HD, -0.01 mm(r1)/0.13 mm(r2) for SD and 0.07 mm(r1)/0.16 mm(r2) for LD.Linear regression indicates no noticeable differences between methods and the raters with respect to bl and bt.

CONCLUSIONS

Relating to the CBCT-device used in this study, LD-CBCT is a promising method to detect and describe buccal and oral periodontal bl and bt. Further studies with human anatomic structures must confirm these results.

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.

Evaluation of the association between gingival phenotype and alveolar bone thickness: A systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis of studies that evaluated the association between gingival phenotype (GP) and the underlying alveolar bone thickness (ABT).

DESIGN

An electronic search was performed in PubMed, Embase, Scopus, ProQuest, and Web of Science. The following inclusion criteria were applied: English original studies that compared the ABT in periodontally healthy patients presenting thin versus thick GPs. Studies that evaluated the correlation between gingival thickness (GT) and ABT were also included. Pooled mean difference (95% confidence interval) was estimated using random-effects maximum likelihood model meta-analysis.

RESULTS

From a total of 1427 retrieved articles, 17 were included. The majority of eight studies that compared the ABT between thick and thin GPs, reported a significantly greater ABT associated with a thick phenotype. Based on the meta-analysis results of six studies, the mean difference between the two phenotypes (0.33 mm) was statistically significant (P < 0.01). The majority of ten studies that investigated the correlation between GT and ABT evidenced a significant positive correlation (r = 0.11 -0.49). The association was more evident in the crestal areas and decreased toward the apex.

CONCLUSIONS

There is contradictory evidence concerning the correlation between soft and hard tissue thickness; however, the meta-analysis revealed a significantly thicker alveolar plate in the presence of a thick phenotype. Since the evaluation of GP could be simply performed using a periodontal probe, such a relationship could provide clinical perspective at the initial examination. This is particularly beneficial in procedures affecting periodontal structures, including immediate implant placement and orthodontic treatments.

Alveolar bone thickness overlying healthy maxillary and mandibular teeth: A systematic review and meta-analysis

OBJECTIVE

To systematically review and meta-analyse the Alveolar Bone Thickness (ABT) overlying healthy teeth. The secondary objective was to review the association of ABT with gender, age, and smoking.

MATERIALS AND METHODS

The PubMed, Embase, Scopus, ProQuest, Web of Science, and Cochrane Library databases were searched up to July 2020. English articles (sample size≥10) which had used CT or CBCT to measure the ABT at clearly defined reference points were included. The maximum likelihood approach meta-analysis was used to estimate the means (95% CIs).

RESULTS

A total of 68 articles were included. The meta-analysis results were as follows: In the anterior maxilla, the mean labial plate thickness ranged from 0.42-1.75mm, while it was thicker for the posterior teeth (0.78-4.31mm). The palatal plate thickness ranged from 0.97-8.13mm. In the anterior mandible, the thickness of labial and lingual plates ranged from 0.4-3.71mm and 0.38-5.44mm, respectively. The alveolar bone was thicker for the posterior teeth both at the labial (0.66-6.31mm) and lingual (2.31-7.77mm) sides. Meta-regression revealed a significant relationship between gender and ABT at several points. There was a controversy regarding the association of ABT with age. No significant difference was evidenced between smokers and non-smokers.

CONCLUSIONS

This study presents a clear image of the alveolar bone structure. Since it has pooled ABT values from various populations, outcomes could be acknowledged as global averages. Therefore, it could provide perspective for several dental procedures, including orthodontic treatments and immediate implant placement.

Comparison of anterior maxillary and mandibular alveolar parameters in African American and Caucasian women: A retrospective pilot study

Purpose

The primary objective of this study was to analyze the thickness and height of alveolar bone around the maxillary and mandibular incisors. Additionally, this study aimed to compare bone parameters between Caucasian (CC) and African American (AA) female patients.

Materials and Methods

In this retrospective pilot study, 50 female subjects (25 CC and 25 AA) were included. The inclusion criteria were AA or CC women between the ages of 18 and 50 with a normo-divergent facial pattern and Angle's class I, end-on class II, or mild class III malocclusion. The distance from the cementoenamel junction (CEJ) to the buccal and lingual alveolar crest; the alveolar ridge thickness at the mid-root and apex; and the buccal and lingual bone thickness at 3, 6, and 9 mm from the CEJ were measured.

Results

No significant difference was found (P>0.05) in the cortical bone thickness at 3 mm, 6 mm, or 9 mm from the alveolar crest between CC and AA populations for most measurements. A significant difference in bone thickness was found (P<0.05) for the lingual surface of the central incisor, with maxillary bone thickness found to be higher than mandibular bone thickness. The measurements of lingual thickness were larger than those of buccal thickness for both races.

Conclusion

There were no differences in maxillomandibular anterior alveolar bone measurements between normo-divergent adult AA and CC women, except for a few parameters at varying locations. However, future studies can be planned based the current pilot study data, which may provide valuable information.

Architectural changes in alveolar bone for dental decompensation before surgery in Class III patients with differing facial divergence: a CBCT study

This study aimed to investigate alveolar bone change around mandibular anterior teeth during orthodontic decompensation in patients with skeletal Class III malocclusion and different vertical facial patterns. The records of 29 consecutive Class III patients selected from those pending two-jaw orthognathic surgery were divided into low (≤ 28°), average (30°-37°), and high (≥ 39°) mandibular plane angle (MPA) groups. The DICOM files of CBCT scans and STL files of digital dental models, taken before (T1) and after (T2) presurgical orthodontic treatment, were imported into Dolphin imaging software to reconstruct dentoskeletal images. T1 and T2 images were superimposed and analyzed for bone thickness and height at the level of root apex on each mid-sagittal slice of six mandibular anterior teeth. Differences between T1 and T2 were analyzed by non-parametric tests and mixed-effect model analysis. The results showed that the measurements of alveolar bone height generally decreased after treatment, regardless of MPA. The facial divergence, incisor irregularity, tooth site, treatment time, and change in proclination were identified as the significant factors affecting alveolar bone thickness and height during treatment. The presurgical orthodontic treatment to decompensate mandibular anterior teeth should be very careful in all MPA groups.

Cone-beam computed tomography-based quantitative analysis of the thickness of mandibular alveolar bone in adult females with different vertical facial patterns

Objectives:

The objectives of the study were to investigate the relationship between the thicknesses of the mandibular alveolar bone in the incisor, canine, premolar, and molar areas in adult female patients with different vertical skeletal patterns using cone-beam computed tomography (CBCT).

Materials and Methods:

CBCT images of 50 adult female patients before orthodontic treatment were analyzed. Based on the mandibular plane angle, they were divided into three groups: Low, average, and high-angle. The thicknesses of the alveolar and cancellous bones of the mandible were measured at the apices of the incisor, canine, first premolar, and first molar on both sides.

Results:

The thicknesses of the alveolar and cancellous bones were significantly larger in the low-angle group than in the high-angle group in all areas. At the incisal and canine areas, the thicknesses of the alveolar and cancellous bones were significantly larger in the average angle group than in the high-angle group. In the canine and first premolar areas, the thickness of the alveolar bone was larger in the low-angle group than in the average angle group.

Conclusions:

Vertical facial pattern is a significant factor in the width of the mandibular alveolar bone, especially in the incisor and canine areas. For planning labiobuccal movement in mandibular canines and incisors, information about the mandibular morphology is thought to be important, particularly in high-angle cases.