An evaluation of root resorption associated with the use of photobiomodulation during orthodontic treatment with clear aligners: a retrospective cohort pilot study

OBJECTIVES

To evaluate the change in tooth root volume using cone-beam computed tomography (CBCT) in a group of patients treated concurrently with clear aligners and an adjunctive photobiomodulation (PBM) device.

MATERIALS AND METHODS

This retrospective cohort pilot study included the records of 32 consecutively treated clear aligner patients (23 female, 9 male) from the private practice of one orthodontist. The PBM group (n = 16) used the device once per day for 5 minutes per arch and was compared with a matched control group (n = 16). A semiautomated segmentation technique was used to obtain tooth volume of anterior teeth from CBCT imaging prior to (T0) and during or immediately following (T1) orthodontic treatment with clear aligners. The change in root volume between time points was assessed.

RESULTS

There was no statistically significant difference between the pre- and posttreatment root volumes of maxillary and mandibular anterior teeth, regardless of which intervention group the patient belonged to (P > .05). There was also no difference in the mean percentage change in root volume between clear aligner patients in this study who were treated with the PBM device compared with a matched control group (P > .05).

CONCLUSIONS

Clear aligner patients in this study who changed their aligners every 3 to 5 days and used adjunctive photobiomodulation therapy did not experience clinically relevant orthodontically induced external root resorption. Due to the small sample size and measurement error in the root segmentation process, the results should be interpreted with caution.

Role of mechano-sensitive non-coding RNAs in bone remodeling of orthodontic tooth movement: recent advances

Orthodontic tooth movement relies on bone remodeling and periodontal tissue regeneration in response to the complicated mechanical cues on the compressive and tensive side. In general, mechanical stimulus regulates the expression of mechano-sensitive coding and non-coding genes, which in turn affects how cells are involved in bone remodeling. Growing numbers of non-coding RNAs, particularly mechano-sensitive non-coding RNA, have been verified to be essential for the regulation of osteogenesis and osteoclastogenesis and have revealed how they interact with signaling molecules to do so. This review summarizes recent findings of non-coding RNAs, including microRNAs and long non-coding RNAs, as crucial regulators of gene expression responding to mechanical stimulation, and outlines their roles in bone deposition and resorption. We focused on multiple mechano-sensitive miRNAs such as miR-21, - 29, -34, -103, -494-3p, -1246, -138-5p, -503-5p, and -3198 that play a critical role in osteogenesis function and bone resorption. The emerging roles of force-dependent regulation of lncRNAs in bone remodeling are also discussed extensively. We summarized mechano-sensitive lncRNA XIST, H19, and MALAT1 along with other lncRNAs involved in osteogenesis and osteoclastogenesis. Ultimately, we look forward to the prospects of the novel application of non-coding RNAs as potential therapeutics for tooth movement and periodontal tissue regeneration.

Tooth root resorption: A review

Tooth root resorption is multifactorial, leading to progressive destruction and eventual loss of tooth root dentin and cement. There are internal and external types of root resorption, each having its variety. The etiology and pathogenesis of tooth root resorption are poorly understood, and the most significant etiological factors are trauma, pulpal infection, tooth bleaching, and orthodontic treatment. Tooth root resorption is primarily asymptomatic; thus, it is revealed accidentally by radiographic examination. Progressive clinical manifestations are pain, tooth discoloration, tooth mobility, and other conditions. Awareness of the causes and risk factors allowing tooth root resorption, and regular radiographic examination, in case of necessity, make it possible to reveal resorption at an early stage and to prevent its further development. Thus, the aim of this study is to present etiopathogenesis, a clinical course, and diagnostic peculiarities of internal and external types of tooth root resorption, enabling practicing dentists to timely diagnose root resorption and take appropriate measures to avoid further complications. Within the limitation of this review, even though the etiopathogenesis of tooth root resorption is yet not fully understood, it is suggested that the etiological factors fall into two groups (endogenic and exogenic) to enhance further understanding of the possible causes and mechanisms of root resorption and allow practitioners to monitor high-risk patients and make timely diagnoses. Moreover, radiographic examination and CBCT are indispensable for the diagnosis of root resorption.

Evaluation of corticision-based acceleration of lower anterior teeth alignment in terms of root resorption and dehiscence formation using cone-beam computed tomography in young adult patients: A randomized controlled trial

INTRODUCTION

No randomized controlled trial (RCT) has compared flapless corticision with the conventional treatment in the non-extraction treatment of crowded lower anterior teeth (LAT) in terms of external apical root resorption (EARR) and dehiscence formation (DF). The aim of this RCT was to investigate these two complications during levelling and alignment of the LAT using cone-beam computed tomography (CBCT) imaging.

METHODS

Patients with mild to moderate crowding of the LAT were included. Subjects were randomly allocated to either the corticision-assisted orthodontic treatment group (CORT) or the traditional orthodontic treatment group (TRAD). In the CORT, three vertical incisions were performed after brackets' placement. CBCT images were taken before starting treatment and after treatment completion to assess the EARR and the DF. Two-sample t-test and Chi-Square tests were used to detect significant differences.

RESULTS

In general, 312 roots of the lower anterior teeth (156 in each group) were examined. Fifty-two patients (14 males and 38 females, mean age 21.38) were recruited. (CORT; n=26, 6 males, 20 females, mean age 21.30); (TRAD; n=26, 8 males, 18 females, mean age 21.46). No statistically significant difference was found between the two groups regarding the overall mean value of EARR following alignment (P=0.436). The greatest recorded resorption values were 0.81 and 1.02 in the CORT and TRAD groups, respectively. At the end of levelling and alignment, there was no statistically significant difference between the two groups regarding the distribution of DF (P=0.780).

CONCLUSION

Corticision as an acceleration technique did not produce any significant side effects on the roots of lower anterior teeth and did not cause additional alveolar bone defects (dehiscence formation) compared to the conventional non-accelerated method of alignment.

Orthodontically induced root resorption: A critical analysis of finite element studies' input and output

INTRODUCTION

Orthodontically induced inflammatory root resorption (OIIRR) constitutes an undesirable risk connected to orthodontic treatment. Finite element analysis (FEA) is a powerful tool to study the risk of OIIRR. However, its efficiency in predicting OIIRR depends on the insertion of the correct inputs and the selection of an output coherent with the clinical failure mechanism.

METHODS

By combining a systematic review with a 3-dimensional FEA, this article discusses which are the implications of using certain periodontal ligament (PDL) properties (linear and nonlinear models) and failure criteria. Six orthodontic loading regimes were simulated in a maxillary premolar: pure intrusion, buccal tipping, and their combination applied with either a light (25 cN) or a heavy (225 cN) force. Three stress parameters in the PDL were compared: von Mises stress, minimum principal stress_, and hydrostatic stress (σ_H).

RESULTS

The comparison between linear and nonlinear models showed notable differences in stress distribution patterns and magnitudes. For the nonlinear PDL, none of the light-force models reached the critical compressive hydrostatic stress of 4.7 kPa, whereas all the heavy-force models reached it. In addition, the regions of critical compressive σ_H matched with the regions with resorption craters in clinical studies. In linear models, the σ_H critical value of 4.7 kPa was reached even in the light-force scenario.

CONCLUSIONS

Only compressive hydrostatic stress in PDL satisfied the requirements to be used as an FEA indicator of OIIRR. However, the requirements were satisfied only when a nonlinear PDL model was considered.

Impact of intraoral non-pharmacological non-surgical adjunctive interventions on orthodontically induced inflammatory root resorption in humans: A systematic review

BACKGROUND

The current systematic review aimed to assess the impact of intraoral non-surgical non-pharmacological adjunctive interventions on orthodontically induced inflammatory root resorption (OIIRR).

SEARCH METHODS

Search without restrictions was performed up to November 2020 in three electronic databases (Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE) for randomized controlled trials (RCTs), prospective and retrospective non-randomized studies. The ROB 2.0 tool was used to assess the quality of the included RCTs, and the ROBINS-I tool was applied to non-randomized clinical studies. The strength of evidence was ranked using GRADE.

RESULTS

Three hundred and sixteen records were initially retrieved. A total of 10 studies, with 236 patients, were finally considered. These studies assessed the effects of mechanical vibration (low-frequency and high-frequency), low-intensity pulsed ultrasound (LIPUS), low-level laser therapy (LLLT) and photobiomodulation (light-emitting devices (LED). While the low-frequency vibration and LED do not seem to affect OIIRR, OIIRR has been reported to be reduced in high-frequency vibration, and LIPUS-treated teeth (differences may not likely be considered clinically relevant). The potential positive effect of LLLT on OIIRR is still debatable. Overall, the existing evidence suggests that the amount of OIIRR observed while using these interventions with traditional orthodontic treatment was not more than that was observed without it.

CONCLUSIONS

Based on a very low level of confidence, it seems that intraoral non-pharmacological non-surgical adjunctive interventions do not affect the amount of OIIRR either positively or negatively to a clinically relevant degree when compared to what is seen with conventional orthodontic treatment alone.

Effects of different wavelengths of low-level laser therapy on orthodontically induced inflammatory root resorption in rats investigated with micro-computerized tomography

INTRODUCTION

The objective of this research was to investigate the effects of different wavelengths low-level laser therapies on orthodontically induced inflammatory root resorption (OIIRR) during orthodontic tooth movement in rats by micro-computerized tomography.

METHODS

Forty Wistar albino rats were divided into 5 groups: control group (A), 405-nm laser group (B), 532-nm laser group (C), 650-nm laser group (D), and 940-nm laser group (E). The left side of group A was used as a positive control (A-PC), and the right side of group A was used as a negative control (A-NC) group. In all groups, the maxillary left first molars were moved mesially by 50 g of force for 14 days. The lasers were performed for 9 minutes on the maxillary left first molar tooth. At the end of the experimental period, OIIRR measurements were performed at the mesial and the distal sides along the mesial root of the maxillary first molars.

RESULTS

The root resorption volume was significantly lower in group A-NC than in groups A-PC, B, and D. The percentage of root resorption was significantly lower in group A-NC than in all other groups. The root resorption volume and the percentage of root resorption in groups C, D, and E were significantly lower than group A-PC. The depth and the width of the lacuna and even the number of mesial lacunae were similar between groups. The distal and the total lacunae were significantly lower in group A-NC than in all other groups except group C.

CONCLUSIONS

The 532-nm, 650-nm, and 940-nm lasers significantly reduced the volume of OIIRR. In addition, the 532-nm laser reduced the number of lacunae both distally and totally than all the other groups.

Chemerin/ChemR23 regulates cementoblast function and tooth resorption in mice via inflammatory factors

BACKGROUND

Periodontitis and orthodontic treatment can lead to inflammatory root resorption (IRR) through an unclear mechanism. Chemerin, a novel chemoattractant protein, is closely associated with inflammation, affects osteoblast and osteoclast differentiation, and may play a role in IRR. We aimed to explore possible roles of the chemerin/ChemR23 interaction in cementoblast function and IRR and reveal a new IRR therapeutic target.

METHODS

Cementoblast function-related gene and protein expression in the immortalized murine cementoblast cell line OCCM-30 after treatment with chemerin and siChemR23 was examined by qRT-PCR and Western blotting.The roles of the MAPK and PI3K-Akt signaling pathways were studied using specific inhibitors. Cementoblast cytokine production under different treatment conditions was measured by ELISA and qRT-PCR. Additionally, we modeled IRR in wild-type and chemerin-overexpressing mice and injected transgenic mice with anti-ChemR23 antibody to block ChemR23. We then calculated the root resorption volume and examined periodontal tissue cathepsin K, Runx2, TNF-α, and IL-6 expression.

RESULT

Chemerin suppressed cementoblast differentiation and mineralization and exerted a proinflammatory effect on cementoblasts. These effects were partially reversed by siChemR23 and reversed to different extents by p38, Erk1/2 and PI3K-Akt pathway inhibition, suggesting p38, Erk1/2 and PI3K-Akt pathways as signaling pathways downstream of chemerin/ChemR23. In vivo, chemerin overexpression worsened IRR. Moreover, chemerin expression was positively correlated with TNF-α, IL-6, and cathepsin K expression and negatively correlated with Runx2 expression. ChemR23 downregulation reversed these effects.

CONCLUSION

Chemerin/ChemR23 induced TNF-α and IL-6 expression dependent on Erk1/2, p38 MAPK and PI3K-Akt signaling pathway activation, thereby regulating cementoblast function and affecting IRR. This article is protected by copyright. All rights reserved.

Orthodontic treatment and root resorption: an overview of systematic reviews

BACKGROUND

Root resorption can be considered the most unfortunate complication of orthodontic treatment.

OBJECTIVE

To evaluate the available evidence regarding orthodontically induced inflammatory root resorption (OIIRR).

SEARCH METHODS

A comprehensive literature search was conducted for the systematic reviews investigating OIIRR published up to 24 May 2020. This was accomplished using electronic databases: MEDLINE via OVID, EMBASE, AMED (Allied and Complementary Medicine Database), PubMed, and Web of Science. Any ongoing systematic reviews were searched using Prospero and a grey literature search was undertaken using Google Scholar and OpenGrey (www.opengrey.eu/). No language restriction was applied.

SELECTION CRITERIA

Only studies investigating OIIRR were included.

DATA COLLECTION AND ANALYSIS

Screening, quality assessment [using the AMSTAR 2 tool (A Measurement Tool to Assess Systematic Reviews)], and data extraction were performed by two authors independently. Information was categorized and narratively synthesized for the key findings from moderate and high-quality reviews.

RESULTS

A total of 2033 potentially eligible studies were identified. After excluding the non-relevant studies, 28 systematic reviews were included. Of which, 20 systematic reviews (71.5%) were of moderate and high-quality level of evidence. The incidence and severity of OIIRR increase with the fixed appliance, especially with heavy force, intrusion, torqueing movements, increased treatment duration, and treatment with extractions or with long apical displacement (particularly for maxillary incisors). There was insufficient evidence regarding most other treatment- and patient-related factors on OIIRR. Following all precautionary measures, pausing treatment and regular monitoring benefits patients with OIIRR.

CONCLUSIONS AND IMPLICATIONS

There is a limited number of high-quality studies in terms of OIIRR. The influence of fixed appliance on root resorption was noted; however, the cause and effect relationship between OIIRR and orthodontic biomechanics has not been confirmed. Avoiding heavy, continuous forces and a greater amount of apical displacement over a long duration of treatment is recommended. Precautionary measures should be carefully considered when treating patients with a high risk of OIIRR.

REGISTRATION

CRD42020166629.

Inhibitory effect of baicalin on orthodontically induced inflammatory root resorption in rats

Objective

This study investigated the inhibitory effect of baicalin on orthodontically induced inflammatory root resorption in rats.

Methods

Forty-five male Wistar rats were randomly divided into three groups of 15 rats each. Fifty grams of force was used to establish an orthodontic tooth movement model. Baicalin (40 mg/kg) was locally injected into rats in the baicalin group at 3-day intervals; concurrently, normal saline was injected into rats in the negative control group. On the 21st day after orthodontic treatment, the tooth movement distance and root resorption area ratio were measured. Histomorphology changes were observed by hematoxylin and eosin staining and immunohistochemistry.

Results

There was no significant difference in tooth movement distance between groups. The root resorption area ratio was significantly lower in the baicalin group than in the negative control group. Runx-2 expression was significantly higher in the baicalin group than in the negative control group, while tumor necrosis factor (TNF)-α expression was significantly lower in the baicalin group than in the negative control group.

Conclusions

Baicalin inhibits orthodontically induced inflammatory root resorption by enhancing the expression of Runx-2 and reducing the expression of TNF-α, but does not affect tooth movement distance.

Leptin reduces in vitro cementoblast mineralization and survival as well as induces PGE2 release by ERK1/2 commitment

Objectives

Juvenile obesity is a complex clinical condition that is present more and more frequently in the daily orthodontic practice. Over-weighted patients have an impaired bone metabolism, due in part to their increased levels of circulating adipokines. Particularly, leptin has been reported to play a key role in bone physiology. Leptin is ubiquitously present in the body, including blood, saliva, and crevicular fluid. If, and to what extent, it could influence the reaction of cementoblasts during orthodontic-induced forces is yet unknown.

Material and methods

OCCM-30 cementoblasts were cultivated under compressive forces using different concentrations of leptin. The expression of ObR, Runx-2, Osteocalcin, Rank-L, Sost, Caspase 3, 8, and 9 were analyzed by RT-PCR. Western blots were employed for protein analysis. The ERK1/2 antagonist FR180204 (Calbiochem) was used and cPLA2 activation, PGE2, and cytochrome C release were further evaluated.

Results

In vitro, when compressive forces are applied, leptin promotes ERK1/2 phosphorylation, as well as upregulates PGE2 and caspase 3 and caspase 9 on OCCM cells. Blockade of ERK1/2 impairs leptin-induced PGE2 secretion and reduced caspase 3 and caspase 9 expression.

Conclusions

Leptin influences the physiological effect of compressive forces on cementoblasts, exerting in vitro a pro-inflammatory and pro-apoptotic effect.

Clinical relevance

Our findings indicate that leptin exacerbates the physiological effect of compressive forces on cementoblasts promoting the release of PGE2 and increases the rate of cell apoptosis, and thus, increased levels of leptin may influence the inflammatory response during orthodontically induced tooth movement.

Medically compromised patients in orthodontic practice: Review of evidence and recommendations

INTRODUCTION

Due to advances in the field of medicine, early diagnosis and high-quality medical management has become available for medically compromised patients. This increases their life expectancy and improves their quality of life. Therefore, orthodontic treatment can be provided to these patients whose medical conditions are well controlled.

OBJECTIVE

This article will discuss some medical conditions that might be seen by orthodontists. Also, recommendations and modifications of the orthodontic treatment plan will be discussed thoroughly.

MATERIALS AND METHODS

A computerized electronic search of the literature was conducted in Google Scholar and PubMed and was limited to publications in English.

RESULTS

Orthodontic management was studied in cases of Infective endocarditis (IE), Thrombocytopenia, Hemophilia, Sickle cell anemia, Thalassemia, Diabetes mellitus (DM), Thyroid Disorders, Asthma, DiGeorge Syndrome, HIV/AIDS, Organ transplantation, Orthodontic management, Juvenile idiopathic arthritis (JIA), Seizure disorders, Autism Spectrum Disorder (ASD), Mood disorders, Schizophrenia and Eating disorders.

Apical root resorption after orthodontic treatment in patients with unilateral cleft lip and palate

OBJECTIVES

The aims of this retrospective longitudinal study were to present the incidence of external apical root resorption (EARR) in the maxillary anterior teeth of patients with complete unilateral cleft lip and palate (CUCLP) and to evaluate the influence of orthodontic treatment variables on the development of EARR.

MATERIAL AND METHODS

Forty-one patients with CUCLP participated in the study. Orthopantomograms (OPGs), taken before (T2) treatment with multiband orthodontic appliances (MBA), and periapical radiographs (PAs) of the maxillary anterior teeth taken at the end (T3) of orthodontic treatment (OT) were assessed for EARR.

RESULTS

The incidence of EARR at T3 (97.6%) was considerably higher than at T2 (51.2%). Central incisors and canines on the cleft side showed a significantly higher score (p < 0.01, p < 0.05 respectively) of EARR in comparison to the same group of teeth on the non-cleft side. Preexisting EARR and abnormal root morphology were identified as predisposing factors for EARR.

CONCLUSIONS

Patients with CUCLP treated with MBA have higher incidence of EARR on the maxillary anterior teeth of the cleft side. Severe EARR is rather rare but more often seen on central incisors of the cleft side.

CLINICAL RELEVANCE

As most of the patients with cleft lip and palate undergo a challenging and long-term OT with MBA, it is of importance to identify the predisposing factors related to the special anatomical features of the bone and teeth located in the cleft area, as well as the special OT needs of these patients.

Effect of micro-osteoperforation on the rate of canine retraction: a split-mouth randomized controlled trial

Background

Among the recent modalities introduced to accelerate orthodontic tooth movement (OTM) is micro-osteoperforations (MOPs), in other words, bone puncturing. The aim of this split-mouth trial was to investigate the effects of MOPs on the rate of OTM.

Methods

Eighteen patients requiring bilateral first premolar extraction and upper canine retraction with maximum anchorage were enrolled in this study. Immediately before canine retraction, three MOPs were randomly allocated to either the right or left sides. MOPs were performed using a mini-screw (1.8 mm diameter, 8 mm length) distal to the canine. Canine retraction continued for 4 months. Data were collected from monthly digital models, in addition to pre- and post-retraction maxillary CBCT images. The primary outcomes were the rate of canine retraction per month and the total distance moved by the canines. The secondary outcomes were the effect of MOPs on anchorage loss, canine root resorption, and pain.

Results

The mean rate of canine retraction in both sides was 0.99 ± 0.3 mm/month. The total distance moved by the canine cusp tip was greater in the MOP than the control side (mean difference 0.06 ± 0.7 mm), which was statistically insignificant (P > 0.05(. The total distances moved by the canine center and apex were significantly greater in the MOP than the control side (mean difference 0.37 ± 0.63 mm (P < 0.05) and 0.47 ± 0.56 mm (P < 0.01) respectively). Insignificant differences were detected regarding anchorage loss and root resorption between both sides (P > 0.05). Mild to moderate pain was experienced following the MOP procedure, which rapidly faded away within 1 week.

Conclusions

Micro-osteoperforations were not able to accelerate the rate of canine retraction; however, it seemed to facilitate root movement.