Effects of orthodontic treatment on human alveolar bone density distribution

The Differential Impact of Clear Aligners and Fixed Orthodontic Appliances on Periodontal Health: A Systematic Review

BACKGROUND/OBJECTIVE

In orthodontic therapy, the periodontal ligament plays a critical role in the bone remodeling process by stimulating osteoblasts in tension zones and promoting bone resorption through osteoclasts in compression zones in response to mechanical stress. These processes are regulated by key cytokines, such as RANKL and IL-1, which are influenced by factors such as patient age and force application. This work evaluates the effectiveness of clear aligners versus traditional braces on periodontal health in patients with periodontitis, following PRISMA guidelines and utilizing specific inclusion and exclusion criteria.

METHODS

A systematic review of 1664 records was conducted, leading to the inclusion of eight studies that focus on the impact of orthodontic treatments on periodontal health. The review identifies various biases present in the literature.

RESULTS

The findings reveal that clear aligners, in contrast to fixed appliances, improve oral hygiene and reduce inflammation, leading to better periodontal outcomes. Fixed appliances, on the other hand, may exacerbate plaque accumulation and inflammation, which can worsen periodontal health.

CONCLUSIONS

Clear aligners offer advantages over fixed appliances in terms of enhancing periodontal health, improving patient compliance, and providing long-term benefits, particularly in patients with severe periodontitis. The effectiveness of clear aligners is linked to better management of periodontal complications and overall oral hygiene. Treatment decisions should be based on patient-specific criteria to optimize outcomes.

Effect of interproximal enamel reduction on interradicular bone volume in clear aligner therapy: a three-dimensional cone-beam computed tomography study

OBJECTIVES

To assess the effect of inter-proximal enamel reduction (IPR) on interradicular bone volume and incisal inclination in patients undergoing clear aligner therapy (CAT).

MATERIALS AND METHODS

The study sample consisted of 60 cases which underwent orthodontic CAT, in a private clinic in Dammam, KSA. A total of 120 CBCT scans (60 pre-treatment and 60 post- treatment) were measured using the CS 3D Imaging software to examine bone volume (using height, width, and depth of the interproximal area) and incisal inclination. The corresponding ClinCheck models were collected to determine the amount and locations of interproximal reduction performed. Little's Irregularity Index values were measured using OrthoCAD software. Paired sample t-test was used to address the measurements of bone height, width, depth, bone volume, and inclination of upper and lower incisors before and after IPR.

RESULTS

IPR did not affect the upper or lower bone volume except at LR3-2 and UL 2 - 1 where a significant difference between the bone volume with and without IPR was detected (p = 0.02 and p = 0.04 respectively). Upper and lower incisor inclination showed a statistically significant decrease after IPR. There was no correlation between IPR and bone volume difference between upper and lower teeth except at LR3-2 and UL 2 - 1.

CONCLUSIONS

IPR had no significant effect on inter-radicular bone volume except at areas of lower right canine-lateral and at areas of upper left central-lateral. There was a positive correlation between the amount of IPR and incisal inclination.

CLINICAL RELEVANCE

The current study findings suggest that while IPR has a minimal and localized effect on bone volume in certain areas, it plays a role in adjusting incisal inclination, highlighting its significance in the careful planning of orthodontic treatment using clear aligners.

Effect of cigarette smoking on alveolar bone thickness and density in patients undergoing leveling and alignment of crowded lower anterior teeth: a controlled clinical trial

OBJECTIVE

To evaluate the effect of cigarette smoking on the alveolar bone thickness and density in patients undergoing leveling and alignment of crowded lower anterior teeth.

METHODS

This controlled clinical trial involved 17 smokers and 17 nonsmokers with mild to moderate crowding of the anterior mandibular teeth. Two cone-beam computed tomography images of the mandible were taken before and after treatment. The length of each tooth root was calculated in each T0 image, and the root was divided into three equal regions. Three lines were drawn parallel to the line of the cementoenamel junction at these three regions of the root, and the previously drawn lines were used to measure bone thickness and bone density.

RESULTS

The mean changes in cortical bone thickness and bone density were significantly smaller in smokers than nonsmokers. Cortical bone thickness and bone density were significantly lower after than before treatment in both smokers and nonsmokers.

CONCLUSION

In addition to all of its known dangers, cigarette smoking may also harm the alveolar bone by decreasing the bone thickness and density during orthodontic treatment in heavy smokers.

The effect of orthodontic treatment on the periodontium and soft tissue esthetics in adult patients

OBJECTIVE

Most patients seek orthodontic treatment to achieve an esthetic outcome. Orthodontic treatment has possible negative sequelae. The aim of this study is to assess these possible effects on the periodontium and tissue esthetics.

METHODS

One hundred fifty-six patients who have completed orthodontic treatment at Jordan University of Science and Technology clinics were recruited. They were divided into extraction and nonextraction subgroups. Another 155 patients never undergoing orthodontic treatment were assessed. The height of papilla, width of keratinized gingiva, gingival recession, degree of tooth display, smile line, crestal bone level, and proximal caries were assessed. Chi- square test was used for categorical/discrete variables while independent t-test was used for continuous variables. The level of significance was set at (p ≤ 0.05).

RESULTS

The mean age was 22 years with no significant difference between the groups. There was a significant difference between "ortho" and "nonortho" groups in tooth display and keratinized gingiva (p = 0.006 and <0.001, respectively). The overall crestal bone level, smile line, recession, and papilla fill did not show any significant differences (p = 0.200, 0.067, 0.120, and 0.066, respectively). The crestal bone level in the upper and lower anterior segments was significantly lower in the "ortho" treated group compared to the "nonortho" treated group (p = 0.002 and 0.005, respectively). A significant difference between "extraction" and "nonextraction" groups was in the width of keratinized gingiva (p = 0.003) and the number of teeth displayed (p < 0.001). Despite reaching statistical significance these differences are not necessarily of clinical significance.

CONCLUSION

Orthodontic treatment clearly affects the periodontal tissues; however, the detrimental effects appear to be minimal. Patients with history of orthodontic treatment might have lower crestal bone levels at certain sites and this should not be confused with periodontal disease.

Effects of Injectable platelet rich fibrin (i-PRF) on reduction of relapse after orthodontic tooth movement: Rabbits model study

OBJECTIVES:

The objective of this study is to determine whether submucosal local injection of i-PRF may affect orthodontic relapse by increasing bone density, which further leads to reducing orthodontic relapse.

MATERIALS AND METHODS:

Forty-five adult male albino rabbits were randomly divided into three groups: group I (control) with 15 rabbits injected with 200 μl of phosphate-buffered saline (PBS), group II with 15 rabbits injected with 200 μl of i-PRF, and group III of 15 rabbits inject with 400 μl of i-PRF. The lower incisors of rabbits moved distally by a modified orthodontic appliance for 2 weeks; then, the appliance was maintained in position to retain the gaining space for 2 weeks. During the retention period, each group was injected with the specific drug every 7 days. After the retention period, teeth were allowed to relapse by removal of the orthodontic appliance. The results were evaluated by measuring the amount of orthodontic relapse and bone density. The statistical analysis performed by ANOVA and Duncan (P < 0.05 was considered significant).

RESULTS:

I-PRF groups showed a significant reduction in the amount of relapse at 10, 13, 17, and 20 days compared to the control group, indicated by the highest percentage of relapse for the control group at the end of the study (20 days); it was (90.4%) in compared to lowest percentage of relapse for i-PRF groups—they were 61.2% and 59.9%, respectively.

CONCLUSION:

Results indicated that i-PRF has the potential to enhance the stability of teeth after orthodontic tooth movement and could have the ability to reduce relapse, probably by increasing the alveolar bone density.

Dental malocclusions are not just about small and weak bones: assessing the morphology of the mandible with cross-section analysis and geometric morphometrics

OBJECTIVES

Dental malocclusions in modern populations would be the result of small and weak jaws developing under low masticatory loads. We assess the validity of this by characterising the external and internal morphology of mandibles affected by class II and III malocclusions and comparing them with those from individuals with different masticatory load patterns.

MATERIALS AND METHODS

CTs from up to 118 individuals exerting intensive, medium and low masticatory loads with harmonic occlusion, and from class II and III individuals, were used to compare their external shape using geometric morphometrics, as well as their internal amount and distribution of cortical bone.

RESULTS

The low-load groups (harmonic, class II and III occlusion) are externally more gracile than the intense and medium load groups. But more relevant in shape variation is a marked allometric pattern, which differentiates class II (small) and III (large) mandibles. Despite gracility, the relative amount of cortical bone in the low-load groups is larger than in the remaining groups.

CONCLUSIONS

There is no evidence that the modern mandible, including class II and III individuals, is intrinsically small and weak. Instead, there is a rather large degree of morphological variation, which could be linked to a lack of constraints derived from low masticatory loads. Thus, the effect of other factors such as genetics, but also basal metabolism, should be looked in more depth.

CLINICAL RELEVANCE

Dental malocclusions are a common disorder whose aetiology has not been unravelled, and several to be considered in the prevention and therapy of malocclusion.

Comparison of Early Implant Failure Rates Between Subjects With and Without Orthodontic Treatment Before Dental Implantation

The present study compared early dental implant failure rates between patients with and without orthodontic treatment before dental implantation. The data of adults who had undergone dental implantation between January 2007 and December 2016 were analyzed retrospectively. A total of 124 subjects with 255 implants were divided into a treatment group (46 subjects, 85 teeth) consisting of patients who had undergone implant surgery after orthodontic treatment and a control group of patients who had not undergone preimplant orthodontic treatment. Implants that failed before permanent crown fabrication were defined as failures. No significant differences in gender or age were found between the treatment group and controls. No significant differences were found in implant failure rates in either jaw between the treatment and control groups. However, the failure rate was still higher in the treatment group (14.81%) than in the control group (3.28%) for the maxilla. Results of this study demonstrate an increased implant failure rate only in the maxilla of patients who underwent orthodontic treatment before dental implantation, especially implant surgery combined with a sinus lift procedure. Further study with a larger sample size and longer follow-up period is necessary to confirm results of the present study and identify other confounding factors.

[Periodontal status assessment before orthodontic treatment and opportune moment selection for orthodontic treatment]

The aesthetic demands of teeth by the public have improved with the increase in the living standard. Orthodontics, which is a method of aesthetic dentistry, is becoming increasingly important. Orthodontic treatment mainly involves the application of orthodontic force to the teeth and guides the reconstruction of the periodontal tissue, thereby changing the position of the teeth at the occlusal bone. Orthodontic treatment can also improve the dental occlusion caused by dentition crowding and teeth mobility to achieve long-term stability of periodontal tissue. The number of patients with periodontal disease is high in China, and the number of patients with periodontal disease that are eager to receive orthodontic treatment is increasing. Hence, the periodontal status during the orthodontic therapy should be explored along with periodontal therapy and orthodontic treatment. This article briefly demonstrates the assessment criteria of periodontal status before orthodontic treatment, the opportune moment selection for orthodontic treatment, and the supportive periodontal therapy. This study helps dentists develop individualized treatment programs and win a balanced, stable, and aesthetic impression.

The Incisive Canal: A Comprehensive Review

The incisive canal, also known as the nasopalatine canal, is an interosseous conduit through the anterior maxilla connecting the oral and nasal cavities. Within this canal lies the nasopalatine nerve and the vascular anastomosis between the greater palatine and sphenopalatine arteries. The embryology of the canal has led to interesting theories explaining its function. Efforts have been made to describe the morphometrics of the incisive canal by radiologic evaluation across sex and ethnicities. This paper aims to review the current literature on the embryology, anatomy, and clinical relevance of the incisive canal.

Efficacy of Cone-Beam Computed Tomography in Evaluating Bone Quality for Optimum Implant Treatment Planning

PURPOSE

This study examined (1) if cone-beam computed tomography (CBCT) can determine relative differences in bone mineral density distribution using clinical images of patients' mandibular bone and (2) if the relative differences can be used to detect the effects of sex and age on bone mineral density distribution.

MATERIALS AND METHODS

Sixty-six clinical CBCT images from patients (36 females and 30 males) of 3 age groups (40, 50, and 60 years) were identified. Alveolar (AB) and basal cortical bone (CB) regions were digitally isolated. A histogram of gray levels, which are proportional to degrees of bone mineralization, was obtained from each region. Mean, variability (SD and coefficient of variation), and percentage differences of gray level parameters between AB and basal CBs were computed.

RESULTS

Significant sex differences in gray level variability were observed within the postmenopausal age group (P < 0.042).

CONCLUSION

These findings suggest that clinical CBCT images can be a valuable tool in providing information on bone quality, which is an important criterion for optimum planning for dental implant placement.

Effects of different loading protocols on the secondary stability and peri-implant bone density of the single implants in the posterior maxilla

BACKGROUND

Immediate or early loading of dental implants becomes a clinically feasible concept.

PURPOSE

The aim was to evaluate the effects of different loading protocols (immediate, early, and delayed) on secondary stability and peri-implant bone density of single implants in the posterior maxilla.

MATERIALS AND METHODS

Thirty-nine implants (Dentium, South-Korea) were placed in 39 patients. After placement, implant stability values (ISQ) and baseline peri-implant bone density values derived from cone-beam computed tomography were recorded. Thirteen implants were included randomly in each loading groups. The secondary ISQ values were recorded during follow-up visits. Peri-implant bone density values were measured 1 year after placement again. Data was statistically analyzed.

RESULTS

Immediate-loaded group showed the lowest ISQ values, 1 month after placement. During the next follow-up visits, delayed-loaded group showed the lowest ISQ values while other groups showed comparable results. Early loading increased the peri-implant bone density greater than the other groups.

CONCLUSIONS

The peri-implant bone of early-loaded implants was significantly denser than that of immediate- and delayed-loaded implants, 1 year after placement. Density increment can be judged as the radiological findings of loaded-bone, which may also reduce the need for histomorphometric analysis of human biopsy to evaluate the bone reaction around the implants.

Assessment of the changes in alveolar bone quality after fixed orthodontic therapy: A trabecular structure analysis

Background. Tooth displacement changes the periodontium. The aim of orthodontic treatment is desired tooth movement with minimum side effects on the alveolar bone quality. The aim of the present study was to assess changes of alveolar trabeculation in children, young adults and adults and the two genders.

Methods. In this cross-sectional study, 63 patients who had been treated in Department of Orthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran, were chosen with convenient sampling method. They were divided into three groups based on their age. Their digitized panoramic radiographs (PRs) were evaluated at six interdental sites from the mesial aspect of the mandibular second molars to the distal aspect of the mandibular first premolars using a visual index. The trabeculation pattern was assigned as either dense (score 3), dense-sparse (score 2) or sparse (score 1). Data were imported to SPSS. Mean of the scores before treatment (score B) and mean of them after treatment (score A) were compared for each group with paired t-test. Changes between score B and sore A of the groups were compared using one-way ANOVA and post hoc tests.

Results. Mean score A was significantly higher than mean score B in children (P = 0.001). In contrast, mean score A was significantly lower than mean score B in young adults (P = 0.003).

Conclusion. Orthodontists should be cautious when treating young adults and adults regarding the probable, yet possibly temporary, negative effects of orthodontic therapy on the alveolar bone quality.

Does Orthodontic Treatment Affect the Alveolar Bone Density?

Few studies involving human participants have been conducted to investigate the effect of orthodontic treatment on alveolar bone density around the teeth. Our previous study revealed that patients who received 6 months of active orthodontic treatment exhibited an ∼24% decrease in alveolar bone density around the teeth. However, after an extensive retention period following orthodontic treatment, whether the bone density around the teeth can recover to its original state from before the treatment remains unclear, thus warranting further investigation.The purpose of this study was to assess the bone density changes around the teeth before, during, and after orthodontic treatment.Dental cone-beam computed tomography (CBCT) was used to measure the changes in bone density around 6 teeth in the anterior maxilla (maxilla central incisors, lateral incisors, and canines) of 8 patients before and after orthodontic treatment. Each patient underwent 3 dental CBCT scans: before treatment (T0); at the end of 7 months of active orthodontic treatment (T1); after several months (20-22 months) of retention (T2). The Friedman test was applied to evaluate the changes in the alveolar bone density around the teeth according to the 3 dental CBCT scans.From T0 to T1, a significant reduction in bone density was observed around the teeth (23.36 ± 10.33%); by contrast, a significant increase was observed from T1 to T2 (31.81 ± 23.80%). From the perspective of the overall orthodontic treatment, comparing the T0 and T2 scans revealed that the bone density around the teeth was relatively constant (a reduction of only 0.75 ± 19.85%). The results of the statistical test also confirmed that the difference in bone density between T0 and T2 was nonsignificant.During orthodontic tooth movement, the alveolar bone density around the teeth was reduced. However, after a period of bone recovery, the reduced bone density recovered to its previous state from before the orthodontic treatment. However, the bone density around ∼10% of the teeth in this region could not recover to 80% of its state from before the orthodontic treatment.

Three-dimensional analysis of incisive canals in human dentulous and edentulous maxillary bones

Background

The purpose of this study was to reveal the structural properties that need to be considered in dental implant treatment by investigating differences between dentulous and edentulous maxillae in the three-dimensional (3D) microstructure of the incisive canals (ICs) and their surrounding bone.

Methods

A total of 40 maxillary bones comprising 20 dentulous maxillae and 20 edentulous maxillae were imaged by micro-CT for 3D observation and measurement of the IC and alveolar bone in the anterior region of the IC.

Results

The Y-morphology canal was most frequently observed at 60% in dentulous maxilla and 55% in edentulous maxilla. There was a significant difference between dentulous and edentulous maxillae in IC diameter and volume, but no significant difference between the two in the major axis of the ICs.

Conclusions

The anatomic structure surrounding the IC has limited area for implant placement. Therefore, where esthetic and long-term maintenance requirements are taken into account, careful attention is needed when setting the placement position. Also, due to the resorption of bone, edentulous maxillae have a different IC morphology from dentulous maxillae, and therefore, a cautious approach is required.

Cervical vertebral bone mineral density changes in adolescents during orthodontic treatment

INTRODUCTION

The cervical vertebral maturation (CVM) stages have been used to estimate facial growth status. In this study, we examined whether cone-beam computed tomography images can be used to detect changes of CVM-related parameters and bone mineral density distribution in adolescents during orthodontic treatment.

METHODS

Eighty-two cone-beam computed tomography images were obtained from 41 patients before (14.47 ± 1.42 years) and after (16.15 ± 1.38 years) orthodontic treatment. Two cervical vertebral bodies (C2 and C3) were digitally isolated from each image, and their volumes, means, and standard deviations of gray-level histograms were measured. The CVM stages and mandibular lengths were also estimated after converting the cone-beam computed tomography images.

RESULTS

Significant changes for the examined variables were detected during the observation period (P ≤0.018) except for C3 vertebral body volume (P = 0.210). The changes of CVM stage had significant positive correlations with those of vertebral body volume (P ≤0.021). The change of the standard deviation of bone mineral density (variability) showed significant correlations with those of vertebral body volume and mandibular length for C2 (P ≤0.029).

CONCLUSIONS

The means and variability of the gray levels account for bone mineral density and active remodeling, respectively. Our results indicate that bone mineral density distribution and the volume of the cervical vertebral body changed because of active bone remodeling during maturation.

Can dental cone beam computed tomography assess bone mineral density?

Mineral density distribution of bone tissue is altered by active bone modeling and remodeling due to bone complications including bone disease and implantation surgery. Clinical cone beam computed tomography (CBCT) has been examined whether it can assess oral bone mineral density (BMD) in patient. It has been indicated that CBCT has disadvantages of higher noise and lower contrast than conventional medical computed tomography (CT) systems. On the other hand, it has advantages of a relatively lower cost and radiation dose but higher spatial resolution. However, the reliability of CBCT based mineral density measurement has not yet been fully validated. Thus, the objectives of this review are to discuss 1) why assessment of BMD distribution is important and 2) whether the clinical CBCT can be used as a potential tool to measure the BMD. Brief descriptions of image artefacts associated with assessment of gray value, which has been used to account for mineral density, in CBCT images are provided. Techniques to correct local and conversion errors in obtaining the gray values in CBCT images are also introduced. This review can be used as a quick reference for users who may encounter these errors during analysis of CBCT images.