Interfaces between orthodontic and periodontal treatment: their current status

The Influence of Orthodontic Treatment on Periodontal Health between Challenge and Synergy: A Narrative Review

By correctly repositioning teeth, orthodontic therapy improves both the function and appearance of an occlusion. The relationship between teeth and the tissues that surround and support them significantly influences these alterations. With ever more adults seeking orthodontic care, orthodontists are increasingly seeing patients with periodontal issues. Concerns about the patient's appearance, such as uneven gingival margins or functional issues caused by inflammatory periodontal diseases, should be accounted for when designing orthodontic treatment plans. Furthermore, orthodontics may increase the chances of saving and recovering a degraded dentition in cases of severe periodontitis. Today, general dentists, dontists, and orthodontists play integrative roles that enable them to achieve the best possible results for their patients. This review will improve the results of interdisciplinary treatments and increase cooperation between dental specialists by drawing attention to the essential connection between orthodontics and periodontics in regular clinical practice.

Perception of Undergraduates in the Field of Periodontology

The dentistry specialty known as periodontology focuses on problems with the tissues that support and surround teeth. A thorough understanding of basic sciences and health care is necessary for periodontology. To ensure that the dentition has adequate form, function, esthetics, and comfort, it is essential to have a thorough understanding of the relationship between periodontal tissues and how it relates to other branches of dentistry, such as restorative dentistry, orthodontics, prosthodontics, and implants. The periodontal ligament is a soft tissue between the alveolar bone and teeth. Since the alveolar bone is the foundation for successful dental treatment, proceeding with subsequent dental procedures, including restorative dentistry, implants, and prosthetic uses, is only possible with sufficient bone support. The current review article aims to assess the perception of undergraduate students regarding periodontics and its range of practice. It also gives a general overview of the field of periodontology by outlining current practices, exploring how students perceive this branch's range of courses, and emphasizing more recent and sophisticated developments.

Knowledge, attitudes and professional practices of ortho-periodontal care of adults: a cross-sectional survey in France

BACKGROUND

Due to increasing numbers of adult patients, orthodontists are being confronted more and more with periodontal problems. Coordination amongst orthodontists, periodontists and general dentists is useful in preventing and stopping periodontal disease. The main objectives of this survey were to evaluate the technical knowledge, techniques and attitudes employed by French orthodontists, periodontists and general dentists in adult dental care.

METHODS

A cross-sectional online survey was distributed to French dentists. The questionnaire, consisting of 30 questions, was divided into six sections covering treatment programs and the forensic environment.

RESULTS

One thousand one hundred twenty-two complete answers were recorded. Adults undergoing orthodontic treatment represented 19.9% of the orthodontists' patients, but only 2.67% of the general dentists' patients. Communication between clinicians was rated as good, greater than 3 out of 5. Before treatment, orthodontists were less alarmed than generalists regarding bleeding, recessions, increased probing depths, halitosis and hyperplasia. During treatment, orthodontists never or only occasionally performed palpation or probing in 54.2% and 84.6% of cases. Gingivitis and recessions were the main reasons for consultations for 22.0% and 20.1% of general dentists and periodontists after orthodontic treatment. Of the practitioners surveyed, 43% felt that they experienced a setback in the ortho-periodontal treatment.

CONCLUSIONS

This study revealed discrepancies in the knowledge and attitudes of practitioners. Therapeutic management remains one of the major challenges of multidisciplinary treatments. Continuing education needs to be further developed in this field.

Numerical and biomechanical analysis of orthodontic treatment of recovered periodontally compromised patients

OBJECTIVE

Generate a finite element (FE) model to simulate space closure and retraction mechanics for anterior maxillary teeth in periodontally compromised dentition, and compare the biomechanical effect of initial force systems with varying magnitude.

MATERIALS AND METHODS

The geometry of an idealized finite element model (FEM) of a maxilla was adapted such that the teeth showed reduced periodontal support together with extruded and flared incisors. In a first step, leveling and alignment of the front teeth were simulated. In a second step, force systems for orthodontic space closure of residual spaces on both sides distal to the lateral incisors were simulated. A combined intrusion and retraction cantilever was modeled, to simulate en masse retraction mechanics with segmented arches and elastic chains. A commercial FE system was used for all model generations and simulations.

RESULTS

Results of the simulations indicated that a force of 1.0 N is too high for space closure of flared front teeth in periodontally damaged dentition, as extreme strains may occur. En masse retraction using cantilever mechanics with lower forces showed a uniform intrusion and retraction movement and thus proved to be a better option for treating patients with a periodontally compromised dentition.

CONCLUSION

The outcome of this study indicates that increased periodontal stresses resulting from severe attachment loss should be seriously considered by careful planning of the orthodontic mechanics and reduction of the applied forces is suggested. The presented cantilever mechanics seems to be an appropriate means for en masse retraction of periodontally compromised extruded front teeth.

Surgical Periodontal Therapy with Recombinant Human Fibroblast Growth Factor-2 in Treatment of Chronic Periodontitis: A Case Report with 2-year Follow-up

We report a case of generalized chronic periodontitis requiring periodontal regenerative therapy. The patient was a 53-year-old woman who presented with the chief complaint of gingival swelling. An initial examination revealed 31.5% of sites with a probing depth of ≥4 mm and 46.3% with bleeding on probing. Radiographic examination showed vertical bone resorption in tooth #33. Horizontal adsorption was also observed in other areas. Based on a clinical diagnosis of severe generalized chronic periodontitis, initial periodontal therapy consisting of plaque control, scaling and root planing, occlusal adjustment, caries treatment, and splint placement was performed. After re-evaluation, surgical periodontal treatment was performed at selected sites. Periodontal regeneration therapy with recombinant human fibroblast growth factor (rhFGF)-2 was performed at #33. Two other sites (#14, 15), which had residual periodontal pockets, were treated by open-flap debridement. After re-evaluation, the patient was placed on a maintenance program. Periodontal regenerative therapy with rhFGF-2 resulted in an improvement in angular bone resorption, which has been properly maintained for 2 years. Continued care is needed to maintain stable periodontal conditions.

The adult orthodontic patient over 40 years of age: association between periodontal bone loss, incisor irregularity, and increased orthodontic treatment need

Objectives

Adult orthodontic treatment, especially in patients over 40 years, is steadily increasing. One causal factor for the treatment need in this age group is periodontal breakdown. The aim of this study was to detect correlations between periodontal problems and orthodontic parameters in interdisciplinary patients.

Methods

This observational, cross-sectional study included 118 patients over 40 years (51 men/67 women; mean age, 58.03 years) classified into three groups according to periodontal breakdown (group I, controls; group II, moderate periodontitis; group III, severe periodontitis). Clinical periodontal and orthodontic parameters as well as the index of orthodontic treatment need (IOTN) were assessed and compared between the groups.

Results

A gradual deterioration of all periodontal and orthodontic parameters according to periodontal bone loss (lowest values in group I; highest values in group III) was observed. Especially groups I and III differed significantly regarding the overjet (p < 0.001) and the little indices of the maxilla (p < 0.001) and mandible (p < 0.010). The IOTN was highest in group III: 90% of the patients with severe periodontitis were classified to have moderate to very great treatment need.

Conclusions

The higher the degree of periodontal breakdown was, the more severe were overjet, overbite, irregularity of the anterior teeth, and the orthodontic treatment need.

Clinical relevance

Adult patients over 40 years represent a challenge for an orthodontic/periodontal treatment approach with high incidence of pathologic tooth migration, orthodontic treatment need, and periodontal breakdown. Therefore, this special patient collective requires a focus in clinical orthodontics and research.

Quantitative evaluation of implemented interproximal enamel reduction during aligner therapy

OBJECTIVES

To investigate the correspondence between programmed interproximal reduction (p-IPR) and implemented interproximal reduction (i-IPR) in an everyday-practice scenario. The secondary objective was to estimate factors that might influence i-IPR to make the process more efficient.

MATERIALS AND METHODS

Fifty patients treated with aligner therapy by six orthodontists were included in this prospective observational study. Impressions were taken at the beginning of treatment and after the first set of aligners. Data on p-IPR, i-IPR and technical aspects of IPR were gathered for 464 teeth. Statistical analyses included the Wilcoxon signed-rank test, Kruskal-Wallis, and multilevel mixed regression.

RESULTS

Mean difference between p-IPR and i-IPR was 0.15 mm (SD: 0.14 mm; P = .0001), with lower canines showing the highest discrepancy. Use of burs and measuring gauges resulted in a smaller difference (respectively: coeff.: 0.09, P = .029; coeff.: -0.06, P = .013). IPR was performed more accurately on the mesial surface of teeth than on the distal surface. Round tripping before IPR resulted in a slightly more precise i-IPR compared to the previous alignment (coeff.: -0.021, P = .041).

CONCLUSIONS

Implemented IPR tends to be less than p-IPR, especially for lower canines and distal surfaces of teeth. Burs tend to provide more precise i-IPR, especially compared to manual strips; however, there is variation between the techniques. Using a measuring gauge tends to increase the precision of i-iPR. As several factors influence the implementation of IPR, particular attention must be paid during the procedure to maximize its precision.

Salivary MRP-8/14 and the presence of periodontitis-associated bacteria in children with bonded maxillary expansion treatment

OBJECTIVES

The aim of this study was to investigate changes in saliva concentration of the inflammatory marker MRP-8/14 and the presence of some periodontitis-associated bacteria in patients with mixed dentition treated with a rigid acrylic, bonded maxillary expander.

METHODS

Fifteen patients in mixed dentition treated with a bonded palatal expander were enrolled in this longitudinal study. Saliva samples were taken before the therapy, as well as in 2 weeks and 3, 6, 9, and 12 months after the beginning of the therapy. In each sample, the levels of MRP-8/14 were determined by ELISA and the presence of 11 bacteria was detected by PCR followed by DNA-DNA hybridization.

RESULTS

Salivary concentration of MRP-8/14 and the amount of Tannerella forsythia, Treponema denticola, and Eikenella corrodens were significantly increased during treatment with bonded maxillary expander. These changes were transient and the maximal levels of MRP-8/14 and periodontitis-associated pathogens were observed 6-9 months after the beginning of the therapy.

CONCLUSION

Therapy with bonded maxillary results in higher MRP-8/14 levels and increased prevalence of some periodontitis-associated bacteria, namely T. forsythia, T. denticola, and E. corrodens. The results suggest the detection of salivary MRP-8/14 levels may be a potential tool to reflect the oral health status in children with fixed orthodontic treatment.

CLINICAL RELEVANCE

Our data suggest that the treatment with bonded maxillary expander might influence the oral health status and should be accompanied by the careful control of the oral health during the therapy.

Research paper: The three-dimensional mechanical response of orthodontic archwires and brackets in vitro during simulated orthodontic torque

Orthodontic archwire rotation around its long axis, known as third-order torque, is utilised to correct tooth rotational misalignments moving the tooth root closer to or away from the cheek through engagement with an orthodontic bracket. Studying the behaviour of archwire and brackets during an applied rotation can aid in better understanding and appreciating the mechanics of third-order torque, potentially allowing for more effective orthodontic treatment protocols. Mechanically characterising archwire behaviour during third-order torque application is a complex task due to their physical scale and geometries. An advanced measurement technique was needed to address these constraints. A three-dimensional (3D) non-contact optical method using a digital image correlation (DIC) system was developed. An orthodontic torque simulator (OTS) was used to apply and measure third-order torque with 0.483 × 0.635 mm (0.019″ x 0.025″) rectangular archwires in tandem with a 3D DIC system, whereby surface deformations and strains could be computed using correlation algorithms. The 3D DIC system was implemented to enable third-order torque experimentation with the OTS while imaging the archwire and bracket surfaces. The 3D DIC system's ability to measure 3D archwire deformations and strains was verified using a finite element model, where comparisons between 3D DIC measurements and calculated results from the model were made to ensure the measurement capabilities of 3D DIC in the context of third-order torque. The 3D DIC system was then used to compare archwire behaviour between stainless steel (SS) and titanium molybdenum alloy (TMA) archwires to study potential clinical differences in archwire behaviour, in which the archwires were rotated with a custom SS rigid dowel (RD) as well as commercial Damon Q orthodontic brackets. The quantification of third-order torque and archwire deformations and strains led to the conclusion that SS archwires led to larger torque magnitudes compared to TMA archwires. The RD resulted in larger archwire strains compared to Damon Q brackets. The 3D DIC system provides a non-contact measurement technique that can further be used with third-order torque experimentation with the OTS.

Combined orthodontic-periodontal treatment in periodontal patients with anteriorly displaced incisors

INTRODUCTION

Flared and elongated incisors are associated with different types of periodontal bone defects, usually horizontal. Combined orthodontic-periodontal treatment is being used in periodontal patients with anterior displacement of the incisors. The purpose of this study was to investigate the changes in periodontal health and the shape of bone defects in the incisors after such combined treatment.

METHODS

Fourteen adults were included in the study. In total, 56 elongated maxillary incisors with horizontal bone defects received orthodontic-periodontal treatment with circumferential supracrestal fibrotomy. To improve bone morphology, periodontal regenerative surgery and guided tissue regeneration were performed on the anterior teeth with angular bone defects after orthodontic treatment. Cone-beam computed tomography scans were taken before treatment (T0), at the end of the orthodontic intrusion (T1), and 6 months after the guided tissue regeneration surgery (T2). Probing pocket depth and clinical attachment loss were examined at T0, T1, and T2. The data were analyzed using paired t tests.

RESULTS

From T0 to T1, clinical attachment loss decreased significantly by 0.29 mm (P <0.05). The distance from the cementoenamel junction to the marginal bone crest decreased by 0.66 mm (P <0.05). The labial side of alveolar bone thickness increased by 0.54 mm (P <0.05), and the lingual side of alveolar bone thickness decreased by 0.46 mm (P <0.05). The shape of the bone defect was changed from horizontal to vertical on some teeth. From T1 to T2, both probing pocket depth and clinical attachment loss improved significantly, and the radiographic examinations showed bone redepositions of 2.15 ± 0.68 mm (P <0.05) vertically and 1.44 ± 0.92 mm (P <0.05) horizontally. The distance from the most apical point of the bone defect to the cementoenamel junction after combined treatment decreased by 2.11 ± 1.30 mm (P <0.05).

CONCLUSIONS

Combined orthodontic-periodontal treatment improved the periodontal conditions of the defective bone sites. Bone morphology, altered by orthodontic intrusion with fibrotomy, can improve the results of subsequent guided tissue regeneration.

Iatrogenic Damage to the Periodontium Caused by Orthodontic Treatment Procedures: An Overview

In orthodontic treatment, teeth are moved in to new positions and relationships and the soft tissue and underlying bone are altered to accommodate changes in esthetics and function. Function is more important than esthetics. The speciality of orthodontics has in addition to its benefits, complications as well as risks associated with its procedures. However the benefits outweigh the risks & complications in most of the treatment cases. Few of the unwanted side effects associated with treatment are tooth discolorations, enamel decalcification, periodontal complications like open gingival embrasures, root resorption, allergic reactions to nickel & chromium as well as treatment failure in the form of relapse.

Periodontal ligament strain induced by different orthodontic bracket removal techniques: nonlinear finite-element comparison study

OBJECTIVES

The goal of this work was to biomechanically analyze several different methods of bracket debonding and compare the strain they induce in the periodontal ligament (PDL).

METHODS

The CT dataset of an anatomical specimen was divided into four segmental models of the mandible. Each model covered one tooth (32, 42, 44, and 47). One of these teeth (32) was characterized by marked loss of periodontal attachment. After suitable finite-element models were generated, material properties were defined as nonlinear for PDL and anisotropic for the alveolar bone. This was followed by simulating four bracket debonding techniques: frontal and lateral torquing, bracket-wing compression, and shear stress applied with specially designed pliers.

RESULTS

The greatest strain was measured at the periodontally compromised tooth site 32 in response to frontal and lateral torquing. Both techniques also resulted in great strain around the other three teeth. Strain was markedly lower with the shear technique and virtually negligible with the compression technique. All simulated tooth sites confirmed the PDL-sparing effect of bracket-wing compression.

CONCLUSION

The severity of PDL strain during orthodontic bracket removal depends on the debonding method used. The technique of compressing the bracket wings appears to trigger the smallest effect on PDL. Clinical studies should be undertaken to confirm these findings.

Numerical simulation and biomechanical analysis of an orthodontically treated periodontally damaged dentition

BACKGROUND AND OBJECTIVE

Once periodontitis has been completely resolved, one common follow-up method is to carry out orthodontic treatment to take advantage of the residual bone, i.e., via tooth intrusion. In this study, the biomechanical behavior of teeth in a reduced periodontium was studied by numerically simulating upper-incisor intrusion accomplished with various orthodontic mechanics.

MATERIALS AND METHODS

Using the finite element method, a patient-customized 3D model of a periodontally reduced dentition was generated in order to simulate tooth movement. The morphology of this upper-jaw model was derived from cone-beam computed tomography (CBCT) datasets of four patients. Material parameters were adopted from previous investigations, including teeth (E=20 GPa), periodontal ligament (PDL) (bilinear elastic; E1=0.05 MPa; E2=0.20 MPa; ε12=7%), and bone (homogeneous, isotropic; E=2 GPa). Two intrusion scenarios were used, the first drawing from Burstone's segmented-arch technique to intrude four splinted incisors at a time, and the second one using cantilevers to intrude single incisors. The aforementioned PDL material parameters were varied in several ways to simulate different biological and biomechanical states of PDL. All simulations were recalculated with an idealized, periodontally intact model to assess the effect of bone loss by way of comparison.

RESULTS

Single-tooth intrusion via cantilever mechanics was accompanied by less rotation than the segmented-arch approach. Both intrusion systems involved significantly greater degrees of tooth displacement and PDL load in the periodontally reduced model.

CONCLUSION

Periodontally reduced dentitions are associated with an increased load on periodontal tissue. This can be counteracted by reducing orthodontic force levels and by selecting mechanics that do not harm the tissue. In so doing, the use of numerical methods may greatly facilitate individualized computer-aided treatment-planning strategies.