Displacement in root apex and changes in incisor inclination affect alveolar bone remodeling in adult bimaxillary protrusion patients: a retrospective study

Measurement of orthodontic tooth movement in lower anterior teeth by means of magnetic resonance imaging- a prospective pilot study

BACKGROUND

During orthodontic treatment, the risk of gingival recession may increase, especially in the mandibular anterior region due to thin alveolar bone. This prospective pilot study aimed to develop a standardized evaluation method based on magnetic resonance imaging (MRI) for analysing tooth movements and tissue dimensions and to investigate the impact on periodontal parameters during orthodontic levelling.

MATERIALS AND METHODS

Participants aged 12 to 18 with lower jaw crowding underwent MRI scans before (T0) and five months into orthodontic treatment (T1). The following tissue dimensions were analysed: thickness of free and supracrestal gingiva (FGT, SGT), thickness of buccal alveolar bone (ABT) at three measurement levels (ABT2, ABT4, ABT8), and gingiva and alveolar bone height (GH, ABH). Additionally, tooth positions (apex position and tooth axis inclination) were determined.

RESULTS

Ten patients (60% female, 40% male) aged 14.33 ± 1.35 years were included after the exclusion of 3 datasets due to motion artefacts. MRI measurements showed significant changes in tooth inclination (2.93 ± 4.77°, p < 0.001), bucco-lingual apex position (-0.45 ± 1.03 mm, p = 0.006), SGT (-0.07 ± 0.19 mm, p = 0.020), ABT8 (0.42 ± 0.59 mm, p < 0.001), ABH (-0.29 ± 0.68 mm, p = 0.006) and GH (0.31 ± 0.9 mm, p = 0.030) between T0 and T1. Inclination changes correlated negatively with FGT (R = -0.422, p < 0.001) and positively with ABT8 (R = 0.404, p = 0.032). Furthermore, ABT8 correlated negatively with buccal apex movement (R=-0.392, p = 0.042). Intra- and interclass correlation coefficients were excellent (0.988 and 0.975).

CONCLUSION

Periodontal tissue changes correlated with tooth inclination or apex position changes due to orthodontic treatment. The pilot study has demonstrated the feasibility of dental MRI as a radiation-free alternative to cone-beam computed tomography for monitoring orthodontic treatment. However, the methodology was susceptible to motion artefacts.

TRIAL REGISTRATION

ISRCTN, ISRCTN12689212. Registered 11 April 2024 Retrospectively registered, http//www.isrctn.com/ISRCTN12689212 .

Changes in alveolar bone remodeling after maxillary anterior retraction using fixed appliances with different periodontal conditions: A retrospective study based on cone-beam computed tomography

INTRODUCTION

This study aimed to compare changes in maxillary anterior alveolar bone remodeling and complication rates in adult patients with different periodontal conditions after maxillary anterior tooth retraction using fixed appliances. In addition, this study analyzed potential factors affecting alveolar bone thickness in patients with periodontitis.

METHODS

A total of 55 adult patients (mean age, 23.53 ± 4.55 years) with Angle Class I or II Division 1 malocclusion with maxillary protrusion were recruited and categorized into the healthy control group (n = 23), stage I periodontitis (P-I) group (n = 17), and stage II periodontitis (P-II) group (n = 15). The maxillary anterior teeth were retracted using a fixed appliance. Cone-beam computed tomography was used to measure the thickness, height, and density of the alveolar bone in the maxillary anterior region before (T1) and after (T2) treatment. The incidences of bone dehiscence and fenestration were documented. Statistical analysis was conducted to evaluate intergroup and intragroup differences. Clinical and cephalometric data were collected to identify factors affecting the changes in alveolar bone thickness using multivariate linear regression analysis.

RESULTS

The labial alveolar bone thickness increased significantly after treatment in all groups, but no differences were observed among the groups. In contrast, the palatal alveolar bone thickness decreased, particularly in the P-I and P-II groups, at the midroot and apical levels (P <0.05). A significant decrease in alveolar bone height was observed in the P-I and P-II groups (P <0.05). The incidence of palatal bone dehiscence was higher in the P-II (84.44%) and P-I (69.61%) groups. Multivariate linear regression analyses revealed that sex, treatment duration, periodontal treatment, changes in tooth inclination, and initial thickness significantly affected palatal alveolar bone thickness changes in patients with periodontitis.

CONCLUSIONS

After retraction of the maxillary anterior teeth with a fixed appliance, the labial alveolar bone of the maxillary anterior teeth thickened, whereas the palatal bone exhibited thinning in adults with periodontitis. The reduction in palatal bone height was more significant in this population than in healthy subjects, along with a higher incidence of palatal bone dehiscence. Bone morphology must be carefully assessed, considering these relevant factors before and during orthodontic treatment.

3D analysis of long-term airway evolution following orthognathic approach of bimaxillary setback surgery without segmental osteotomy

Long-term evolution of airway space following bimaxillary setback surgery has been seldom reported. 31 patients with bimaxillary protrusion were included in this study. Bimaxillary setback surgery without segmental osteotomy were performed to alleviate their facial deformity. The pharyngeal airway volume and most constricted airway cross-sectional areas before surgery (T0), one week (T1), and one year (T2) after surgery were measured by 3D image analysis depending on CT data. To exclude the impact of post operational swelling on the airway analysis, the airway changes of another cohort of 10 orthognathic patients without sagittal maxilla or mandible movements were also measured as a control. Body mass index (BMI) was noted and analyzed as well to rule out its interference. Results showed that, in bimaxillary setback surgery patients, no post operational upper pharyngeal airway sleep disorders (UASD) occurred. The mean ± SD of pharyngeal airway volume (PAV) and the minimum cross-sectional area (Min-CSA) at T0 were 14921.3 ± 3910.1 mm3 and 147.9 ± 75.8 mm2, reduced to 11834.1 ± 3916.3 mm3(79.3%, P < 0.001) and 111.6 ± 60.6 mm2(75.4%, P < 0.001 at T1, and recovered to 14686.8 ± 3917.1 mm3(97.1%, P < 0.001) and 132.7 ± 62.8 mm2 (89.6%, P < 0.001) at T2. In control group patients, the mean ± SD of PAV were 16540 ± 5518 mm3 at T0 vs 14248 ± 4340 mm3 at T1 (P = 0.051) and Min-CSA were 156 ± 61 mm2(T0) vs159 ± 61 mm2 at T1 (P = 0.849). Besides, At T0 and T2, the mean ± SD of the BMI was 20.19 ± 1.80 and 20.04 ± 2.53 respectively (P = 0.772). This study suggests that Orthognathic bimaxillary setback reduce the pharyngeal airway space. However, the reduction will largely alleviate in long-term. Aesthetic oriented bimaxillary setback approach is relatively safe when the setback distance is controlled appropriately.

Extraction camouflage treatment of a skeletal Class III malocclusion with severe anterior crowding by miniscrews and driftodontics in the mandibular dentition

An 18-year-old Chinese woman presented with chief complaints of crowded teeth and mild mandibular prognathism. Clinical and imaging examinations revealed a concave profile, a protruded chin, increased lower anterior facial height mild, skeletal Class III and Angle's Class III malocclusion, with anterior crossbites, and crowded teeth. Extraction camouflaged therapy combined with miniscrews skeletal anchorage was employed to relieve crowding and retract the mandibular anterior teeth. The total active treatment time was 31 months. After treatment, functional occlusion and smile esthetics were significantly improved.

A Comparative Study of Traditional and Computer-aided Surgical Simulation Guides in Orthognathic Correction of Bimaxillary Protrusion

OBJECTIVE

To compare the efficacy of traditional occlusal guides with computer-aided surgical simulation (CASS) guides in enhancing postoperative outcomes for patients with bimaxillary protrusion.

METHODS

This retrospective study evaluated 34 patients undergoing anterior maxillary and mandibular subapical osteotomy at the Plastic Surgery Hospital of the Chinese Academy of Medical Sciences. Fourteen patients were treated using traditional occlusal guides, whereas 20 patients were treated with CASS guides (median age 28.6 years, median follow-up 259 days). Pre and postoperative cephalometric indicators were measured using cephalometric software. Data analysis was conducted using SPSS 14.0, with significant differences determined at P < 0.05.

RESULTS

All 34 patients experienced primary healing without complications. Follow-up indicated significant improvements in key cephalometric measurements in the CASS group compared with the traditional group, including mandibular position (SNB angle, P < 0.001), jaw relationship (ANB angle, P < 0.001), facial angle (FH-NPo, P = 0.002), and condyle-to-sella distance (Co-S, P = 0.024). The CASS group also showed better aesthetic outcomes, with significant reductions in overjet (P = 0.012), overbite (P = 0.001), and improved alignment of upper and lower incisors (U1-L1 angle, P = 0.031).

CONCLUSION

CASS-guided surgery offers a superior alternative to traditional methods for treating bimaxillary protrusion, providing more precise and aesthetically pleasing results. This study highlights the significant advantages of using advanced digital simulation and 3-dimensional printing technologies in orthognathic surgery.

Mandibular cortical bone remodeling characteristics in patients with extraction: A cone-beam computed tomography study

INTRODUCTION

This study evaluated the labial and lingual cortical bone remodeling characteristics of mandibular central incisors after retraction, which remain controversial among orthodontists.

METHODS

Cortical bone remodeling and central incisor movement of 33 patients (aged 23.64 ± 4.30 years) who underwent mandibular first premolar extraction and incisor retraction at the crestal (S1), midroot (S2), and apical (S3) levels were analyzed using superimposed cone-beam computed tomography images on the basis of voxel-based registration of the mandibular stable region. Multivariate linear regression was used to explore the relationships between labial bone remodeling/tooth movement (BT) ratios and factors such as the ANB angle, mandibular plane angle (Mp-SN), and incisor movement patterns. The patients were divided into 4 groups according to the lingual cortical bone remodeling condition and the relationship between posttreatment incisor roots and the original lingual cortical bone border. At the 3 levels (S1, S2, and S3), the classifications of cortical bone remodeling of the mandibular incisors were calculated; t tests were used to compare the amount of labial and lingual bone remodeling, BT ratios, and lingual bone remodeling/root over the original border (BRo) ratios.

RESULTS

The mean labial BT ratios at all 3 levels were close to 1. Multivariate linear regression indicated that the tooth movement pattern negatively correlated with the BT ratio at the S2 and S3 levels (P <0.05). Lingual bone apposition occurs when the root penetrates the original lingual cortical bone border in most patients. BRo ratios can more accurately reflect the inherent remodeling ability of the lingual cortical bone than BT ratios. The mean lingual BRo ratios were (1) S1 level: mandibular left central incisor (T31), 0.87 ± 0.25 and mandibular right incisor (T41), 0.86 ± 0.25; (2) S2 level: T31, 0.81 ± 0.12 and T41, 0.80 ± 0.22; and (3) S3 level: T31, 0.76 ± 0.20 and T41, 0.83 ± 0.26. There was no significant difference between labial BT ratios and lingual BRo ratios at the S2 and S3 levels.

CONCLUSIONS

The amount of labial cortical bone resorption caused by mandibular incisor retraction showed varied relationships with the amount of tooth movement. Bodily retraction may decrease the labial BT ratios at the S2 and S3 levels. Active lingual cortical bone apposition occurred when the roots penetrated the original lingual border and exhibited strong remodeling ability.

CBCT Evaluation of Alveolar Bone Change and Root Resorption after Orthodontic Treatment: A Retrospective Study

BACKGROUND

For years, there has been a long debate about the impact of orthodontic treatment on the periodontium of patients. Therefore, it is important to understand the effects of orthodontic forces on the periodontium. The objective of this study was to evaluate the height of the alveolar bone at the four surfaces of specific teeth and the root length of the central incisors before and after orthodontic treatment.

MATERIALS AND METHODS

CBCTs from a group of fifty patients were evaluated before (T0) and after orthodontic treatment (T1). Evaluations of the alveolar bone were performed by measuring the distance from the most apical point of the marginal portion to the CEJ at the buccal (B-ABL), lingual (L-ABL), mesial (M-ABL), and distal (D-ABL) surfaces of the central incisor (CI), first premolar (1st PM), and first molar (1st M). Meanwhile, root resorptions were evaluated by measuring the distance from the center of the tooth at the CEJ to the most apical point of the central incisor.

RESULTS

The reduction in the alveolar bone level was highest at the buccal segment (75%) and lowest at the distal (42%) segment, although the decrease was not statistically significant. Root resorption, in terms of reduction in the total length, was detected in the upper central incisor.

CONCLUSIONS

Fixed orthodontic treatment can produce a significant reduction in root length, but not at the level of the alveolar bone.

Alveolar bone changes around maxillary incisors after intrusion and retraction with controlled tipping versus bodily movement : A retrospective cone-beam computed tomography study

OBJECTIVE

To compare the effect of maxillary incisor intrusion and retraction with controlled tipping (CT) versus bodily movement (BM) in extraction cases on alveolar bone height and thickness, using cone-beam computed tomography (CBCT). Correlations between changes in alveolar dimensions and crown or root retraction, incisor inclination, and intrusion were also investigated.

MATERIALS AND METHODS

In all, 144 incisors of 36 women were retrospectively evaluated. All patients were treated with anterior intrusion and retraction with either controlled tipping (CT) (group 1) or bodily movement (BM) (group 2). CBCT scans were taken before and after retraction and intrusion and measurements of alveolar bone height and thickness at the level of mid-root and root apex were measured. The prevalence of dehiscence was also calculated.

RESULTS

Labial bone thickness (BT) increased at the level of the root apex with increased total BT in the CT group (p < 0.05). The BM group showed decreased palatal BT. Significant vertical bone loss with an increased incidence of dehiscences occurred on the palatal side in both groups. Changes in palatal bone area was negatively correlated with the amount of root apex retraction, while the total BT at the level of root apex was positively correlated with amount of intrusion.

CONCLUSIONS

Bodily retraction can result in reduced palatal bone dimensions and an increase risk of iatrogenic sequelae following anterior retraction in extraction cases. Vertical bone loss and an increased incidence of dehiscences is to be expected following anterior retraction. Careful attention must be paid to the bone boundary conditions to avoid moving the incisors out of the alveolar housing.

Bone Remodeling of Maxilla after Retraction of Incisors during Orthodontic Treatment with Extraction of Premolars Based on CBCT Study: A Systematic Review

Background: Incisor retraction is often a crucial phase in ongoing orthodontic treatment, with significant implications for alveolar remodeling mechanisms. There are two prevailing theories which seek to explain this. According to the first, teeth move with the bone, while according to the second, teeth move within the bone. This systematic review seeks to assess morphometric changes in the maxillary alveolar process resulting from incisor retraction following premolar extraction and to evaluate the potential for bone remodeling associated with orthodontic movement. Methods: The study was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following electronic databases were searched: PubMed, Google Scholar, Web of Science EMBASE and the Cochrane Central Register of Controlled Trials. The databases were searched using the following keywords: "Bone remodeling and retraction of incisors", "Alveolar bone and incisor retraction", "Bone thickness and incisor retraction", and "Bone changes and orthodontic treatment". Search filters were utilized to identify relevant papers and articles written in English and published during the last 10 years. Based on the information provided in their abstracts, papers and articles were selected according to the following criteria: randomized clinical trials (RCTs), controlled clinical prospective trials (CCTs), and retrospective studies. Articles unrelated to the study's scope or failing to meet inclusion criteria were excluded. These generally comprised individual case reports, case series reports, literature reviews, experimental studies, studies with limited data (including conference abstracts and journal writings), studies involving an unrepresentative group of patients (less than 10 patients), studies concerning patients with syndromes, and animal experiments. The remaining articles which were deemed relevant underwent comprehensive reference review and such journals as the American Journal of Orthodontics, Dentofacial Orthopedics, International Orthodontics, Journal of Clinical Orthodontics, and Angle Orthodontist were manually searched. Results: Seven articles meeting the inclusion criteria articles were selected for final evaluation, with a total of 284 participants, including 233 women and 51 men. During the analysis of the results included in the publications, a lack of homogeneity was observed, rendering a reliable statistical analysis and heterogeneity assessment unobtainable. Noteworthy disparities in methodologies and measurements posed a risk of drawing inappropriate conclusions. Consequently, emphasis was placed on qualitative analysis, emphasizing the need for standardization in future studies of a similar nature, to enable valid and comparable analyses. Conclusions: The research findings incorporated in this review demonstrate that significant bone loss occurs because of incisor retraction, which diminishes distance between the bone surface and the root surface on the palatal aspect. The magnitude of this change may vary, contingent upon both the extent of incisor displacement and alterations in their inclination, thereby affecting the positioning of the root tips. This change is significantly higher in adults than in growing adolescents. The rationale behind this assertion lies in the widely recognized phenomenon of declining cellular activity with advancing age. The decrease in the speed and intensity of cellular changes may explain the diminished capacity for remodeling as patient age increases. There is ongoing discourse regarding alterations in the volume of bone on the labial aspect of the alveolar process. Further research is necessary to measure whether bone remodeling during orthodontic movement is contingent upon other factors, such as the speed and biomechanics of retraction, the level of applied orthodontic force, and the patient age.

A quantitative three-dimensional comparative study of alveolar bone changes and apical root resorption between clear aligners and fixed orthodontic appliances

BACKGROUND

This study aimed to evaluate and compare the alveolar bone changes and to investigate the prevalence and severity of orthodontically induced inflammatory root resorption (OIIRR) of maxillary incisors in patients who received treatment with clear aligners (CA) versus conventional fixed appliances (FA), using cone-beam computed tomography (CBCT).

METHODS

One hundred sixty maxillary incisors from 40 patients with similar baseline characteristics based on the American Board of Orthodontics discrepancy index scores were divided into the CA and FA groups. The dentoalveolar quantitative changes were analyzed using pre- (T0) and post-treatment (T1) CBCT. The measured parameters included alveolar bone thickness (ABT), alveolar bone height (ABH), root length (OIIRR), and maxillary incisor inclinations.

RESULTS

Post-treatment, the average palatal and total ABT significantly decreased in central and lateral incisors in the FA group. In contrast, the CA group's average labial ABT of the lateral incisors decreased considerably. Regarding the ABH, both groups showed significant labial and palatal marginal bone resorption. In both groups, root lengths significantly decreased after treatment (p < 0.005). The inter-group comparison revealed that ABT and root length had significantly decreased in the FA group compared to the CA group, while the ABH showed no significant difference between the two groups. The mean absolute reductions of ABT and OIIRR in the CA group were significantly less (- 0.01 ± 0.89 and 0.31 ± 0.42) than those in the FA group (0.20 ± 0.82 and 0.68 ± 0.97), respectively.

CONCLUSIONS

CA and FA treatments appear to cause a significant ABT reduction and a statistically significant increased OIIRR in the maxillary incisor region, with a greater extent expected with FA treatment. However, the increased OIIRR values in the majority of both groups' cases were not clinically significant. Both treatment modalities resulted in a significant ABH reduction, with the highest found in the labial side of lateral incisors in the CA group.

Detailed Correlation between Central Incisor Movement and Alveolar Bone Resorption in Adults with Orthodontic Premolar Extraction Treatment: A Retrospective Cohort CBCT Study

Background: This study aims to explore the detailed correlation between the movement of maxillary and mandibular central incisors and alveolar bone resorption in adults who had orthodontic premolar extraction treatment. Methods: A total of 63 adult patients (mean age, 24.41 years) who received orthodontic treatment with the extraction of four first premolars were included in this study. CBCT images were obtained before and after treatment. Three-dimensional evaluations of the movement of 252 central incisors (126 maxillary and 126 mandibular incisors) and alveolar bone changes were conducted. Four points were used to describe the incisor movement: C (cusp point), R (root apex point), M (mid-point of root neck), and L (labial cementoenamel junction point). The thickness of labial and palatal alveolar bone was assessed at the crestal, mid-root, and apical levels of incisors. The results were analyzed with Spearman’s correlation and multilinear regression. Results: Matching the measurements of central incisor movement and alveolar bone resorption, significant correlations could be observed. For maxillary central incisors, the labial alveolar bone resorption at the crestal level was correlated with the movement of Point L (r = 0.290, p < 0.05), and the labial alveolar bone resorption at the apical level was correlated with Point M (r = 0.387, p < 0.05). For mandibular central incisors, the labial alveolar bone resorption at the apical level was correlated with the movement of Point M (r = 0.493, p < 0.05) and R (r = 0.498, p < 0.01); the palatal alveolar bone resorption at the mid-root level with Point M (r = -0.170, p < 0.01); and the palatal alveolar bone resorption at the apical level with Point R (r = 0.177, p < 0.01). Conclusions: This study investigated the concrete correlations between central incisor movement and alveolar bone resorption in adults after orthodontic treatment with premolar extraction. It is potentially helpful for orthodontists to have a relatively accurate prediction of alveolar bone resorption based on the specific movements of central incisors and to reduce the risk of alveolar bone resorption by better adjusting the three-dimensional movement types of incisors.

Difference in the alveolar bone remodeling between the adolescents and adults during upper incisor retraction: a retrospective study

The purpose of this study was to compare the difference of alveolar bone remodeling between the adolescents and adults in the maxillary incisor area during retraction. This retrospective study included 72 female patients who needed moderate anchorage to correct the bimaxillary protrusion. Subjects were further divided into the minor group (n = 36, 11-16 years old) and adult group (n = 36, 18-35 years old). Digital lateral cephalography and cone beam CT scanning were taken in each patient before (T0) and after treatment (T1). Cephalometry was conducted to assess incisor retraction, while alveolar bone thickness (ABT), alveolar bone distance (ABD), and alveolar bone area (ABA) were detected to assess changes in the alveolar bone. No difference in the inclination of upper incisors was observed at both T0 and T1 between two groups. Changes in the alveolar bone showed a similar tendency with bone apposition on the labial side and bone resorption on the palatal side in both groups. Less increase in the labial ABT (T1-T0) and more decrease in the palatal ABT (T1-T0) was found in the adult group, leading to less total ABT in the adult group. Higher reduction in ABD (T1-T0) was found in the adult group. Moreover, more decrease in the ABA (T1-T0) was found in the adult group. Adult patients have less alveolar bone support after treatment when compared with young adolescents. Orthodontists should take the age into consideration to reduce the potential periodontal risks during the treatment planning.

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.

Three-Dimensional Digital Image Analysis of Skeletal and Soft Tissue Points A and B after Orthodontic Treatment with Premolar Extraction in Bimaxillary Protrusive Patients

Aim. To investigate the effect of changes in incisor tip, apex movement, and inclination on skeletal points A and B and characterize changes in skeletal points A and B to the soft tissue points A and B after incisor retraction in Angle Class I bimaxillary dentoalveolar protrusion. Methods. Twenty-two patients with Angle Class I bimaxillary dentoalveolar protrusion treated with four first premolar extractions were included in this study. The displacement of skeletal and soft tissue points A and B was measured using cone-beam computed tomography (CBCT) using a three-dimensional coordinate system. The movement of the upper and lower incisors was also measured using CBCT-synthesized lateral cephalograms. Results. Changes in the incisal tip, apex, and inclination after retraction did not significantly affect the position of points A and B in any direction (x, y, z). Linear regression analysis showed a statistically significant relationship between skeletal point A and soft tissue point A on the anteroposterior axis (z). Skeletal point A moved forward by 0.07 mm, and soft tissue point A moved forward by 0.38 mm, establishing a ratio of 0.18: 1 (r = 0.554, p < 0.01). Conclusion. The positional complexion of the skeletal points A and B was not directly influenced by changes in the incisor tip, apex, and inclination. Although the results suggest that soft tissue point A follows the anteroposterior position of skeletal point A, its clinical significance is suspected. Thus, hard and soft tissue analysis should be considered in treatment planning.

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.