The association between orthodontic treatment and temporomandibular disorders diagnosis and disease characteristics

BACKGROUND

The association between orthodontic treatment and temporomandibular disorders (TMD) has been contentious in the literature.

OBJECTIVES

To analyse the associations between orthodontic treatment and TMD diagnosis and diseases characteristics.

METHODS

This case-control study included 291 individuals, 192 TMDs and 99 controls. All patients underwent assessment based on a questionnaire and a clinical examination according to Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Differences in orthodontic treatment between TMDs and controls, as well as across different TMD diagnoses within the TMD group were analysed. Patients who underwent orthodontic treatment were compared to those who did not, regarding their trauma history, bruxism, aggressive teeth brushing, level of oral hygiene, pain scores, muscle tenderness scores and subjective sleep quality.

RESULTS

Of the 291 participants, 119 (40.9%) underwent orthodontic treatment and 172 (59.1%) had no orthodontics experience. Orthodontic treatment included: mandibular orthodontic treatment (102 subjects) and maxillary orthodontic treatment (113 subjects) of those 47 used a headgear. Following multivariate analysis among TMDs, orthodontic treatment was associated with a good level of oral hygiene versus poor (Odds ratio [OR]: 5.17 [1.04-25.59]), lower number of tender muscles [OR = 0.84 (0.74-0.96)] and lower (better) Pittsburgh Sleep Quality Index (PSQI) scores (OR = 0.86 [0.76-0.97]). None of the studied parameters maintained a statistically significant association with orthodontic treatment in the multivariate analysis among the entire study population.

CONCLUSIONS

Utilising a holistic approach, this study supports the main hypothesis that orthodontic treatment is not associated with TMD diagnosis and disease characteristics.

The effect of the dental follicle volume of palatally impacted canines on the relative position of the adjacent teeth

OBJECTIVE

To assess if the dental follicle volume of palatally impacted canines (PICs) affects the relative root position of the adjacent lateral incisors (LIs) and first premolars (FPs).

MATERIALS AND METHODS

A retrospective cross-sectional study of 49 patients with unilaterally PICs with dental follicles who had CBCT imaging previously taken. Four orthodontic centers in different countries provided the sample. A mean difference of 5° between the angular measurements (mesiodistal tip, buccolingual inclination, or mesiodistal rotation) of the LI and FP adjacent to the PIC and the controls was considered clinically relevant. A value of 0.05 was set for significance level and a power of 80%. The minimum sample size was determined to be 26 patients. These patients were further assigned to an LI sample (n = 49) and an FP sample (n = 23), dependent on the direct contact of the dental follicle to that adjacent tooth. A manual segmentation technique was used to obtain the volumetric measurements of the dental follicle. Angular measurements of adjacent teeth were then compared to the contralateral nonimpacted side, which acted as the control. A multivariant regression analysis was performed using IBM SPSS software, and statistical significance was set at α = 0.05.

RESULTS

Adequate intra-rater reliability was accomplished. The multivariant regression analysis implied that there is no difference in the mean change in the tip, torque, and rotation of the LI and FP between the impacted and control sides when dental follicle volumes are considered (P = .509 for the LI sample and P = .804 for the FP sample).

LIMITATIONS

CBCT imaging of dental follicle border delimitations, partial volume effect, and scattering are limitations. This is a convenience sample where the FP subsample is small.

CONCLUSION

The dental follicle volume of the PICs does not seem to influence the relative position of the adjacent LI and FP mesiodistal tip, buccolingual inclination, and mesiodistal rotation. Early intervention could have been suggested to avoid certain malocclusion traits if significant displacements were demonstrated.

Resolvin D1 improves allograft osteointegration and directly enhances osteoblasts differentiation

Introduction

Allografts are the most common bone grafts for repairing osseous defects. However, their use is associated with an increased risk for infections, donor disease transmission and osteointegration deficiency. Resolvin D1 (RvD1) is an endogenous lipid with a scientifically proven pivotal role in inflammation resolution and osteoclastogenesis inhibition. Yet, its biological relevance as a potential bone regenerative drug has been scarcely studied. Here, we aim to investigate the RvD1 effect on allograft osteointegration in the alveolar bone regeneration (ABR) murine model.

Methods

ABR model consisted of osseous defects that were generated by the extraction of the maxillary first molar in C57BL/6 mice. The sockets were filled with allograft and analyzed via RNA sequencing. Then they were locally injected with either RvD1 or saline via single or repeated administrations. The mice were sacrificed 2W after the procedure, and regenerated sites were analyzed using µCT and histology. First, MC3T3-E1 preosteoblasts were plated with IL-17 pro-inflammatory medium, and RANKL/OPG ratio was measured. Secondly, the MC3T3-E1 were cultured w/o RvD1, for 3W. Osteoblasts' markers were evaluated in different days, using qRT-PCR and Alizarin Red staining for calcified matrix.

Results

In vivo, neither allograft alone nor single RvD1 administration promote bone regeneration in comparison to the control of spontaneous healing and even triggered an elevation in NR1D1 and IL1RL1 expression, markers associated with inflammation and inhibition of bone cell differentiation. However, repeated RvD1 treatment increased bone content by 135.92% ± 45.98% compared to its specific control, repeated sham, and by 39.12% ± 26.3% when compared to the spontaneous healing control group (n=7/group). Histologically, repeated RvD1 reduced the number of TRAP-positive cells, and enhanced allograft osteointegration with new bone formation. In vitro, RvD1 rescued OPG expression and decreased RANKL/OPG ratio in IL-17 pro-inflammatory conditions. Furthermore, RvD1 increased the expression of RUNX2, OSX, BSP and OC/BGLAP2 and the mineralized extracellular matrix during MC3T3-E1 osteoblasts differentiation.

Conclusions

Repeated administrations of RvD1 promote bone regeneration via a dual mechanism: directly, via enhancement of osteoblasts' differentiation and indirectly, through reduction of osteoclastogenesis and RANKL/OPG ratio. This suggests that RvD1 may be a potential therapeutic bioagent for osseous regeneration following allograft implantation.

The labiopalatal impacted canine: Accurate diagnosis based on the position and size of adjacent teeth: A cone-beam computed tomography study

INTRODUCTION

Labiopalatal impacted canines (L-PICs) occur when the canines lie between central and lateral incisors, with their tip palatal to the central incisor and part of their crown labial to the lateral incisor. Because of their unusual position, they are often misdiagnosed, and their orthodontic resolution fails. This study aims to provide clinicians with pathognomonic features for early and accurate positional diagnosis of L-PICs.

METHODS

The L-PIC sample included 21 subjects with full diagnostic records. The control group of normally erupted canines was taken from a previous study. Clinical photographs, 2-dimensional radiographs, and cone-beam computed tomography were used to evaluate the positions of the adjacent incisors and first premolars, the canine incisor index, and the mesiodistal width of the lateral vs central incisors.

RESULTS

Central incisors adjacent to L-PICs showed significant mesial root angulation, labial root inclination, and mesiolabial crown rotation, whereas lateral incisors presented significant distal root angulation, palatal root inclination, and mesiolabial crown rotation, in comparison to controls. The roots of the central and lateral incisors were divergent, in contrast to the controls, in which they were slightly convergent. The first premolar positions were not affected. The mean canine incisor index was significantly bigger in L-PICs vs the controls, suggesting a palatal canine. The lateral incisor widths were similar between the groups.

CONCLUSIONS

This study provides the orthodontist with evidence-based clinical and radiographic red flags for diagnosing L-PIC, which may allow timely initiation of orthodontic treatment and correct planning of mechanotherapy.

Resolvin D1 shows osseous-protection via RANK reduction on monocytes during orthodontic tooth movement

The study aimed to investigate the role of RvD1 in acute and prolonged sterile inflammation and bone remodeling. A mouse model of sterile inflammation that involves bone resorption was used to examine endogenous RvD1 kinetics during inflammation. Application of exogenous RvD1 significantly inhibited bone remodeling via osteoclast reduction, alongside an anti-inflammatory secretome shift, increased macrophages recruitment and reduction of T-cytotoxic cells. In vitro and in vivo, RvD1 led to significant reduction in RANK expression which reduce osteoclastogenesis in a dose-dependent manner. Taken together, the data shows a dual role for RvD1, as a potent immunoresolvent agent alongside an osteoresolvent role, showing a potential therapeutic agent in bone resorption associated inflammatory conditions.

3D Analysis of maxillary incisor root inclinations in cases of unilateral maxillary canine impaction

OBJECTIVES

To evaluate the association between maxillary incisor root inclinations and unilateral canine impaction.

METHODS

A retrospective cross-sectional study of 59 pre-treatment CBCT scans (23 palatal impactions, 10 buccal impactions, and 26 comparison patients). Using Dolphin 3-D Imaging software (Chatsworth, CA), relative incisor angulations to a 3D palatal plane and the shortest distance between the canine crown and the root of the closest lateral incisor were calculated. A one-way analysis of variance was used to determine whether there were any differences between the three independent groups of impactions concerning the four continuous dependent variables incisor root inclination for each maxillary incisor.

RESULTS

Patients with unilaterally impacted maxillary canines demonstrate significant differences in the root inclination position on the ipsilateral (0.0001 > P = 0.002) but not contralateral side. While palatal impactions (PIC) are associated with buccally positioned roots of the ipsilateral lateral (-9.05 degrees) and central incisors (-7.91 degrees), buccal impactions (BIC) are only associated with palatally positioned roots of the ipsilateral lateral incisors (+10.40 degrees) alone. A more labial position of the lateral incisor root was correlated with a more proximally located, coronally positioned, and medially displaced adjacent PIC (0.013 > P < 0.026).

LIMITATIONS

This is a retrospective cross-sectional convenience sample.

CONCLUSIONS

Patients with impacted maxillary canines, whether PIC or BIC, do not show generalized retroclination or proclination of all four maxillary incisor roots. Instead, changes in incisor root inclination were only ipsilateral to the impacted canine. BIC is only associated with palatal displacement of the ipsilateral lateral incisor root, whereas PIC is associated with labial root displacement of both ipsilateral incisors.

Immune Changes Induced by Orthodontic Forces: A Critical Review

Orthodontic tooth movement (OTM) is generated by a mechanical force that induces an aseptic inflammatory response in the periodontal tissues and a subsequent coordinated process of bone resorption and apposition. In this review, we critically summarize the current knowledge on the immune processes involved in OTM inflammation and provide a novel insight into the relationship between classical inflammation and clinical OTM phases. We found that most studies focused on the acute inflammatory process, which ignites the initial alveolar bone resorption. However, the exact mechanisms and the immune reactions involved in the following OTM phases remain obscure. Recent studies highlight the existence of a typical innate response of resident and extravasated immune cells, including granulocytes and natural killer (NK), dendritic, and γδT cells. Based on few available studies, we shed light on an active, albeit incomplete, process of resolution in the lag phase, supported by continuously elevated ratios of M1/M2 macrophage and receptor activator of nuclear factor κB ligand/osteoprotegerin ratio. This partial resolution enables tissue formation and creates the appropriate environment for a transition between the innate and adaptive arms of the immune system, essential for the tissue's return to homeostasis. Nevertheless, as the mechanical trigger persists, the resolution turns into a low-grade chronic inflammation, which underlies the next, acceleration/linear OTM phase. In this stage, the acute inflammation dampens, and a simultaneous process of bone resorption and formation occurs, driven by B and T cells of the adaptive immune arm. Excessive orthodontic forces or tooth movement in periodontally affected inflamed tissues may hamper resolution, leading to "maladaptive homeostasis" and tissue loss due to uncoupled bone resorption and formation. The review ends with a brief description of the translational studies on OTM immunomodulation. Future studies are necessary for further uncovering cellular and molecular immune targets and developing novel strategies for controlling OTM by local and sustained tuning of the inflammatory process.

γδT Cells Are Essential for Orthodontic Tooth Movement

Sustained mechanical forces applied to tissue are known to shape local immunity. In the oral mucosa, mechanical stress, either naturally induced by masticatory forces or externally via mechanical loading during orthodontic tooth movement (OTM), is translated, in part, by T cells to alveolar bone resorption. Nevertheless, despite being considered critical for OTM, depletion of CD4⁺ and CD8⁺ T cells is reported to have no impact on tooth movement, thus questioning the function of αβT cells in OTM-associated bone resorption. To further address the role of T cells in OTM, we first characterized the leukocytes residing in the periodontal ligament (PDL), the tissue of interest during OTM, and compared it to the neighboring gingiva. Unlike the gingiva, monocytes and neutrophils represent the major leukocytes of the PDL. These myeloid cells were also the main leukocytes in the PDL of germ-free mice, although at lower levels than SPF mice. T lymphocytes were more enriched in the gingiva than the PDL, yet in both tissues, the relative fraction of the γδT cells was higher than the αβ T cells. We thus sought to examine the role of γδT cells in OTM. γδT cells residing in the PDL were mainly Vγ6⁺ and produced interleukin (IL)-17A but not interferon-γ. Using Tcrd-GDL mice allowing conditional ablation of γδT cells in vivo, we demonstrate that OTM was greatly diminished in the absence of γδT cells. Further analysis revealed that ablation of γδT cells decreased early IL-17A expression, monocyte and neutrophil recruitment, and the expression of the osteoclastogenic molecule receptor activator of nuclear factor-κβ ligand. This, eventually, resulted in reduced numbers of osteoclasts in the pressure site during OTM. Collectively, our data suggest that γδT cells are essential in OTM for translating orthodontic mechanical forces to bone resorption, required for relocating the tooth in the alveolar bone.

Analytical methodology to measure periodontal bone morphometry following orthodontic tooth movement in mice

Introduction

Basic research in orthodontics is commonly conducted in rodents. However, experimental studies on orthodontic tooth movement (OTM) lack a standard method to examine OTM and periodontal changes. This study describes a unifying protocol for the analysis of OTM and associated bone microarchitectural changes in mice using microcomputed tomography (µCT).

Methods

Mice (10 animals/group) were divided into control and OTM groups. OTM was generated by anchoring a nickel–titanium closed-coil spring to the upper incisors to pull the upper left first molar. A third group of TNFα −/− mice was added since these are known to have slower OTM. Using µCT, we implemented and tested a number of methods to measure OTM distance and examine 3D bone morphometric parameters associated with OTM in mice.

Results

In total, we tested five methods to measure the OTM distance in mice. The results indicated that measuring the intermolar diastema, and assessing tooth movement relative to the anterior root of the zygomatic arch, displayed the lowest standard deviation and enabled optimal detection of intergroup differences. We also developed two protocols for µCT analysis of the periradicular bone that yielded no false-positive results. Our results revealed that including the width of the periodontal ligament rather than excluding it from the region of interest in mice detected more statistically significant differences in the morphometric parameters between the OTM and control sides and between WT and TNFα −/− mice despite more subtle differences.

Conclusions

We, therefore, propose new guidelines for a standardized μCT-based method to analyse OTM and the extent of the periradicular bone structural changes in mice.

Colon Cancer-Associated Fusobacterium nucleatum May Originate From the Oral Cavity and Reach Colon Tumors via the Circulatory System

Fusobacterium nucleatum is a common oral bacterium that is enriched in colorectal adenomas and adenocarcinomas (CRC). In humans, high fusobacterial CRC abundance is associated with chemoresistance and poor prognosis. In animal models, fusobacteria accelerate CRC progression. Targeting F. nucleatum may reduce fusobacteria cancer progression and therefore determining the origin of CRC F. nucleatum and the route by which it reaches colon tumors is of biologic and therapeutic importance. Arbitrarily primed PCR performed previously on matched same-patients CRC and saliva F. nucleatum isolates, suggested that CRC F. nucleatum may originate from the oral cavity. However, the origin of CRC fusobacteria as well as the route of their arrival to the tumor have not been well-established. Herein, we performed and analyzed whole genome sequencing of paired, same-patient oral, and CRC F. nucleatum isolates and confirmed that CRC-fusobacteria originate from the oral microbial reservoir. Oral fusobacteria may translocate to CRC by descending via the digestive tract or using the hematogenous route during frequent transient bacteremia caused by chewing, daily hygiene activities, or dental procedures. Using the orthotropic CT26 mouse model we previously showed that IV injected F. nucleatum colonize CRC. Here, we compared CRC colonization by gavage vs. intravenous inoculated F. nucleatum in the MC38 and CT26 mouse orthotropic CRC models. Under the tested conditions, hematogenous fusobacteria were more successful in CRC colonization than gavaged ones. Our results therefore provide evidence that the hematogenous route may be the preferred way by which oral fusobacteria reach colon tumors.

The impact of alloplast and allograft on bone homeostasis: Orthodontic tooth movement into regenerated bone

BACKGROUND

The aim of the study is to examine bone healing following augmentation with allograft or β-tricalcium phosphate (β-TCP) and evaluate orthodontic tooth movement (OTM) into the augmented sites.

METHODS

The study included two parts. Part I included the alveolar bone regeneration model. Osseous defects were created by extraction of the maxillary first molars in C57BL/6 mice, and the sockets were filled with allograft, β-TCP, or left unfilled (n = 6/group). Mouse allograft was prepared by a novel method using long bones. Maxillae were collected at 2, 4, and 6 weeks for microcomputed tomography (μCT) and histological analysis. In Part II, OTM was performed after full bone healing, through grafted and unfilled sockets (n = 10/group), and the second molar shift was assessed using μCT.

RESULTS

Bone volume and trabeculation were reduced in β-TCP compared with allograft and non-grafted groups at 2 and 4 weeks post-grafting, but similar at 6 weeks. Graft particles could be detected at 2 weeks post-grafting for β-TCP, and at 2 and 4 weeks for allograft. Increased osteoclasts' presence was observed in the β-TCP group at 2 and 4 weeks compared with allograft and control. OTM was similar in the two graft groups, but impaired versus the non-grafted controls.

CONCLUSION

β-TCP and allograft induce full normal healing but alter OTM into the regenerated sites.

Immunorthodontics: in vivo gene expression of orthodontic tooth movement

Orthodontic tooth movement (OTM) is a “sterile” inflammatory process. The present study aimed to reveal the underlying biological mechanisms, by studying the force associated-gene expression changes, in a time-dependent manner. Ni-Ti springs were set to move the upper 1^st-molar in C57BL/6 mice. OTM was measured by μCT. Total-RNA was extracted from tissue blocks at 1,3,7 and 14-days post force application, and from two control groups: naïve and inactivated spring. Gene-expression profiles were generated by next-generation-RNA-sequencing. Gene Set Enrichment Analysis, K-means algorithm and Ingenuity pathway analysis were used for data interpretation. Genes of interest were validated with qRT-PCR. A total of 3075 differentially expressed genes (DEGs) were identified, with the greatest number at day 3. Two distinct clusters patterns were recognized: those in which DEGs peaked in the first days and declined thereafter (tissue degradation, phagocytosis, leukocyte extravasation, innate and adaptive immune system responses), and those in which DEGs were initially down-regulated and increased at day 14 (cell proliferation and migration, cytoskeletal rearrangement, tissue homeostasis, angiogenesis). The uncovering of novel innate and adaptive immune processes in OTM led us to propose a new term “Immunorthodontics”. This genomic data can serve as a platform for OTM modulation future approaches.

Bovine Bone Promotes Osseous Protection via Osteoclast Activation

The current study aimed at investigating the long-term biological mechanisms governing bone regeneration in osseous defects filled with bovine bone (BB). Tooth extraction sockets were filled with BB or left unfilled for natural healing in a C57BL/6 mouse alveolar regeneration bone model (n = 12). Seven weeks later, the alveolar bone samples were analyzed histologically with hematoxylin/eosin and tartrate-resistant acid phosphatase staining. A separate group (n = 10) was used for RNA sequencing. Osteoclast inhibition was induced by zoledronic acid (ZA) administration at 2 wk postextraction in a third group (n = 28) for examination of osseous changes and cellular functions with micro-computed tomography and quantitative reverse transcription polymerase chain reaction, respectively. Histological and radiological osseous healing was observed in both BB-filled and normal-healing sockets. However, BB regenerated bone showed significant robust expression of genes associated with bone homeostasis and osteoclasts' function. Osteoclasts' inhibition in BB-filled sockets led to decreased bone resorption markers and reduced bone formation to a greater extent than that observed in osteoclasts' inhibition with natural healing. BB displays long-term biologically active properties, despite a naive osseous histological appearance. These include activation of osteoclasts, which in turn promotes osseous remodeling and maturation of ossified bone.

The impact of alloplast and allograft on bone homeostasis: Orthodontic tooth movement into regenerated bone

BACKGROUND

The aim of the study is to examine bone healing following augmentation with allograft or β-tricalcium phosphate (β-TCP) and evaluate orthodontic tooth movement (OTM) into the augmented sites.

METHODS

The study included two parts. Part I included the alveolar bone regeneration model. Osseous defects were created by extraction of the maxillary first molars in C57BL/6 mice, and the sockets were filled with allograft, β-TCP, or left unfilled (n = 6/group). Mouse allograft was prepared by a novel method using long bones. Maxillae were collected at 2, 4, and 6 weeks for microcomputed tomography (μCT) and histological analysis. In Part II, OTM was performed after full bone healing, through grafted and unfilled sockets (n = 10/group), and the second molar shift was assessed using μCT.

RESULTS

Bone volume and trabeculation were reduced in β-TCP compared with allograft and non-grafted groups at 2 and 4 weeks post-grafting, but similar at 6 weeks. Graft particles could be detected at 2 weeks post-grafting for β-TCP, and at 2 and 4 weeks for allograft. Increased osteoclasts' presence was observed in the β-TCP group at 2 and 4 weeks compared with allograft and control. OTM was similar in the two graft groups, but impaired versus the non-grafted controls.

CONCLUSION

β-TCP and allograft induce full normal healing but alter OTM into the regenerated sites.

Bone regeneration with bovine bone impairs orthodontic tooth movement despite proper osseous wound healing in a novel mouse model

BACKGROUND

The aim of this study was to investigate the biological mechanisms underlying alveolar bone regeneration (ABR) and orthodontic tooth movement into bovine bone (BB) regenerated sites.

METHODS

Two mouse models were established in C57BL/6 mice. The ABR model was based on osseous defects filled with BB. The orthodontic tooth movement-ABR model was used to move a molar into the regenerated site. Osseous morphometric analysis and tooth movement distance were evaluated with micro-CT. Histologic characteristics and osteoclast (OCS) accumulation were evaluated by hematoxylin and eosin and tartrate-resistant acid phosphatase staining (TRAP). Expression and location of the receptor activator of nuclear factor-kappa B (RANKL) and of osteoprotegerin (OPG) were evaluated by immunofluorescent staining.

RESULTS

Bone healing peaked at 4 weeks. The distance of the orthodontic tooth movement into the bovine bone was significantly reduced versus that of the nonbovine bone controls. BB particles accumulated along the root's pressure side during orthodontic treatment. Despite the osteoclasts' presence adjacent to the BB particles, no BB resorption was observed. Increased RANKL expression was seen at the orthodontic tooth movement pressure zone, without any change in OPG expression.

CONCLUSION

The two novel mouse models show that the lack of resorption of BB xenografts renders them inadequate for proper orthodontic tooth movement at a later stage.

Fap2 Mediates Fusobacterium nucleatum Colorectal Adenocarcinoma Enrichment by Binding to Tumor-Expressed Gal-GalNAc

Fusobacterium nucleatum is associated with colorectal cancer and promotes colonic tumor formation in preclinical models. However, fusobacteria are core members of the human oral microbiome and less prevalent in the healthy gut, raising questions about how fusobacteria localize to CRC. We identify a host polysaccharide and fusobacterial lectin that explicates fusobacteria abundance in CRC. Gal-GalNAc, which is overexpressed in CRC, is recognized by fusobacterial Fap2, which functions as a Gal-GalNAc lectin. F. nucleatum binding to clinical adenocarcinomas correlates with Gal-GalNAc expression and is reduced upon O-glycanase treatment. Clinical fusobacteria strains naturally lacking Fap2 or inactivated Fap2 mutants show reduced binding to Gal-GalNAc-expressing CRC cells and established CRCs in mice. Additionally, intravenously injected F. nucleatum localizes to mouse tumor tissues in a Fap2-dependent manner, suggesting that fusobacteria use a hematogenous route to reach colon adenocarcinomas. Thus, targeting F. nucleatum Fap2 or host epithelial Gal-GalNAc may reduce fusobacteria potentiation of CRC.

Tumor Targeting by Fusobacterium nucleatum: A Pilot Study and Future Perspectives

Colorectal adenocarcinoma (CRC) is a common tumor with high mortality rates. Interestingly, CRC was found to be colonized by the oral anaerobic bacteria Fusobacterium nucleatum, which accelerates tumor progression and enables immune evasion. The CRC-specific colonization by fusobacteria is mediated through the recognition of tumor displayed Gal-GalNAc moieties by the fusobacterial Fap2 Gal-GalNAc lectin. Here, we show high Gal-GalNAc levels in additional adenocarcinomas including those found in the stomach, prostate, ovary, colon, uterus, pancreas, breast, lung, and esophagus. This observation coincides with recent reports that found fusobacterial DNA in some of these tumors. Given the tumorigenic role of fusobacteria and its immune evasion properties, we suggest that fusobacterial elimination might improve treatment outcome of the above tumors. Furthermore, as fusobacteria appears to specifically home-in to Gal-GalNAc—displaying tumors, it might be engineered as a platform for treating CRC and the above common, lethal, adenocarcinomas.

Identification of salivary protein biomarkers for orthodontically induced inflammatory root resorption

PURPOSE

Orthodontically induced inflammatory root resorption (OIIRR) is one of the most prevalent and unavoidable consequence of orthodontic tooth movement. The aim of this study was to discover potential diagnostic protein biomarkers for detection of OIIRR in whole saliva (WS).

MATERIAL AND METHODS

Unstimulated WS was collected from 72 subjects: 48 OIIRR patients and 24 untreated, generally healthy, age and gender matched controls. Radiographic assessment of periapical x-rays of four upper incisors taken before and 9 months after bonding was done. High-abundance proteins were depleted followed by two-dimensional-gel-electrophoresis and quantitative mass spectrometry (qMS). Finally, to initially validate qMS results, Western blotting was performed.

RESULTS

qMS revealed differentially expressed proteins in the moderate-to-severe OIIRR group, which have never been found in WS before. Additionally, in the moderate-to-severe young OIIRR group, the pathogenetic mechanisms related to actin cytoskeleton regulation and Fc gamma R- mediated phagocytosis were detected, while in adults- to focal adhesion. Preliminary validation by Western blotting of fetuin-A and p21-ARC indicated expression profile trends similar to those identified by qMS.

CONCLUSION

The significance of WS novel proteomic methodologies is clearly demonstrated for detecting new OIIRR biomarkers as well as for unveiling possible novel pathogenetic mechanisms in both young and adult patients.

Effects of the subcranial approach on facial growth and development

OBJECTIVE: To analyze the long-term effects of subcranial surgery for anterior skull base tumors on facial growth.

STUDY DESIGN AND SETTING: Retrospective study (1994 to 2004) in a university-affiliated hospital. Of 108 patients who underwent a subcranial surgical approach for anterior skull base tumors, six adolescents and five young adults fulfilled study entry criteria for age and follow-up data availability (mean, 3.2 ± 2 years). Cephalometric x-ray films monitored postoperative facial growth. Anteriorly and posteriorly measured horizontal and vertical maxillary growth were compared with normal values.

RESULTS: All subjects had superiorly positioned maxillae (shorter in patients with long-standing pathologies). The upper incisor teeth were proclined relative to the cranial base reference planes. All cephalometric changes were within a 10 percent deviation of normal values.

CONCLUSIONS: Subcranial surgery for these tumors minimally affects vertical facial skeleton growth. Early surgery is essential for unaffected horizontal growth.

SIGNIFICANCE: Guidelines for anterior skull base tumor surgery in adolescents and young adults.

© 2007 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Overcoming the oral aspects of -self-mutilation: description of a method

BACKGROUND/AIM

Self-injurious behavior (SIB) is a serious and chronic condition frequently seen in special needs populations, affecting 10% to 17% of individuals diagnosed with intellectual and/or developmental disabilities. A 2.5-year-old infant with SIB, whose presenting symptoms were severe tongue and lip lacerations accompanied by much hemorrhage, is presented here to illustrate the problem and to show how this may be prevented.

MATERIALS AND METHODS

An appliance is described which effectively limits the damage caused by SIB and permits rapid healing of existing injuries.

RESULTS

The method provides for a stable, retentive, and comfortable device on the infant's undererupted and largely nonretentive crowns of the deciduous teeth as well as for all permanent teeth in children, adolescents, and adults.

CONCLUSIONS

The appliance has been successfully employed for the past 10 years in patients with SIB who have attended for treatment in the Special Needs Clinic in our Department.

Etiology of maxillary canine impaction: a review

This article is a review that enumerates the causes of impaction of the maxillary permanent canines, including hard tissue obstructions, soft tissue lesions, and anomalies of neighboring teeth, and discusses the much-argued relationship between environmental and genetic factors. These phenomena have been shown in many investigations to accompany the diagnosis of canine impaction and have been presented as unrelated anomalous features, each of which is etiologically construed as genetic, including the aberrant canine itself. While in general the influence of genetics pervades the wider picture, a guidance theory proposes an alternative etiologic line of reasoning and interpretation of these studies, in which the same genetically determined anomalous features provide an abnormal milieu in which the canine is reared and from which it is guided in its misdirected and often abortive path of eruption.

[Impacted teeth and the six incarnations of resorption]

There are six distinct types of resorption of dental hard tissue that occur in association with unerupted and impacted permanent teeth. These pathologic entities differ markedly from one another in terms of their aetiology, their treatment and their prognosis. In several of them, the continued existence of the affected tooth may be in danger while in others, conservative treatment may halt the resorption process and provide for a successful outcome. The treatment approach is specific for each type and is entirely dependant on the diagnosis. This presentation will discuss prevalence, aetiology, presenting symptoms and clinical signs, radiographic features, histopathology, differential diagnosis, treatment and prognosis in relation to each of the conditions.

Influence of common fixed retainers on the diagnostic quality of cranial magnetic resonance images

INTRODUCTION

Orthodontists are often asked to remove fixed retainers before magnetic resonance imaging (MRI). This study was undertaken to assess the effects of 2 commonly used fixed retainers on MRI distortion and whether they should be removed.

METHODS

MRI scans were performed on a dry skull with Twistflex (Dentaurum, Ispringen, Germany) and Ortho Flex Tech (Reliance Orthodontic Products, Itasca, Ill) retainers. Two neuroradiologists independently ranked the distortions. The influence of the fixed retainers' alloys, their distance to the area of diagnosis, location, strength of the magnetic field, and the spin-echo sequence were examined. Statistical analysis included kappa and Pearson chi-square tests.

RESULTS

Ortho Flex Tech retainers caused no distortion. Twistflex retainers caused distortion in 46% of the tests in areas close to the retainer (tongue and jaws). Maxillary fixed retainers and the combination of maxillary and mandibular fixed retainers further increased the distortion. Greater distortion was observed with 3-T magnetic fields and T1-weighted spin-echo sequences.

CONCLUSIONS

Removal of the Ortho Flex Tech retainer is unnecessary before MRI. Removal of the Twistflex should be considered if the MRI scans are performed to diagnose areas close to the fixed retainers, when 3-T magnetic fields and T1-weighted sequences are used, and when both maxillary and mandibular fixed retainers are present.

Deep submersion: severe phenotype of deciduous-molar infraocclusion with biological associations

OBJECTIVE

To evaluate the clinical manifestation of and treatment modalities for this severe phenotype of infraocclusion and to examine relationships between deep submersion and the occurrence of other dental anomalies.

MATERIALS AND METHODS

The experimental sample consisted of 25 orthodontic patients with at least one deciduous molar in infraocclusion greater than 5 mm. Dental records were used to assess severity of infraocclusion, treatment modality, and presence of other dental anomalies (tooth agenesis, small maxillary lateral incisors, palatally displaced canines, and distal angulation of mandibular second premolars).

RESULTS

The sample included 14 females and 11 males, age 7 to 14 years (mean age 10.1 years). The mean infraocclusion depth was 9 mm, with a range of 5-18 mm. The crowns of the adjacent teeth were severely tilted toward the infraoccluded tooth, space was lost in the dental arch, and the successor premolars were impacted in all cases. Treatment consisted of space regaining, surgical extraction of the deciduous molar, and space maintenance. The impacted premolar erupted spontaneously in 95% of the cases. There was a significant increase in prevalence of dental anomalies in the deep-submersion sample compared with that of reference values (P < .001).

CONCLUSIONS

The treatment modality used in this sample resulted in spontaneous eruption of the impacted premolar in most cases. Markers for early diagnosis of deep submersion include other dental anomalies, severe tilt of adjacent teeth, and local space loss. The increased prevalence of other dental anomalies supports a shared genetic etiology.

LL-37 opsonizes and inhibits biofilm formation of Aggregatibacter actinomycetemcomitans at subbactericidal concentrations

Host defense peptides are immediate responders of the innate immunity that express antimicrobial, immunoregulatory, and wound-healing activities. Neutrophils are a major source for oral host defense peptides, and phagocytosis by neutrophils is a major mechanism for bacterial clearance in the gingival tissue. Dysfunction of or reduction in the numbers of neutrophils or deficiency in the LL-37 host defense peptide was each previously linked with proliferation of oral Aggregatibacter actinomycetemcomitans which resulted in an aggressive periodontal disease. Surprisingly, A. actinomycetemcomitans shows resistance to high concentrations of LL-37. In this study, we demonstrated that submicrocidal concentrations of LL-37 inhibit biofilm formation by A. actinomycetemcomitans and act as opsonins and agglutinins that greatly enhance its clearance by neutrophils and macrophages. Improved uptake of A. actinomycetemcomitans by neutrophils was mediated by their opsonization with LL-37. Enhanced phagocytosis and killing of A. actinomycetemcomitans by murine macrophage-like RAW 264.7 cells were dependent on their preagglutination by LL-37. Although A. actinomycetemcomitans is resistant to the bactericidal effect of LL-37, our results offer a rationale for the epidemiological association between LL-37 deficiency and the expansion of oral A. actinomycetemcomitans and indicate a possible therapeutic use of cationic peptides for host defense.

Failure of treatment of impacted canines associated with invasive cervical root resorption

OBJECTIVES

To propose invasive cervical root resorption (ICRR) as an unrecognized and/or overlooked etiologic factor in the failure of response of an impacted tooth to orthodontic traction and to underline the importance of cone beam computerized tomography (CBCT) for early and accurate diagnosis of ICRR.

MATERIALS AND METHODS

Fourteen patients (age 13-21 years) with impacted canines (15 canines) that had failed to respond to orthodontic forces and that exhibited ICRR formed the case series for this investigation. The initial diagnosis, treatment, clinical and radiographic expression of failure, and adverse effects on adjacent teeth were analyzed.

RESULTS

Initial diagnosis had been performed on plane radiographs. The orthodontist was absent during surgery in 11 patients. Nine canines had been exposed by open procedures. ICRR was not related to the severity of impaction. Its diagnosis was made on existing radiographs, new films, and/or new CBCT. The severity of the lesions was Class 3 or 4, and the teeth were finally extracted. Loss of anchorage characterized 11 patients. Apical resorption of the roots of adjacent teeth was diagnosed in 9 patients.

CONCLUSIONS

ICRR is a frequently undiagnosed or unrecognized cause of failure of orthodontic resolution of impacted canines and should be distinguished from replacement resorption. CBCT should be used for its early detection and accurate assessment of potential damage to adjacent anchor teeth.

Orthodontic-associated localized gingival recession of lower incisors: who should treat it?

Gingival recession of lower incisors in the young population has become more prevalent in association with the increased uptake of orthodontic treatment. The two main predisposing factors are thin gingival biotype and bone dehiscence caused by labially displaced roots. Management is sometimes challenging, and the achievement of a successful result requires close cooperation between the orthodontist and periodontist. This article proposes a decision tree, which includes both orthodontic and periodontal considerations, to help the clinician in making the correct diagnosis and choosing the most suitable treatment in post-orthodontic gingival recessions.

[Failure in the orthodontic treatment of impacted maxillary canines]

Maxillary canine impaction occurs in 1-3% of most Western populations and its orthodontic treatment is often difficult. Failure to resolve the impaction is not uncommon and may lead to malpractice lawsuits. The information in the literature about the reasons for non-resolution of this condition is sparse and unsubstantiated. This encourages the dispensing of inappropriate treatment that may result in severe tooth, soft and hard tissue damage as well as a prolonged treatment period. This review describes the epidemiology, pathogenesis and the wide range of reasons that may lead to failure to resolve the canine impaction. It shows that a lack of appreciation of anchorage demands and inaccurate positional diagnosis of the 3-D location and orientation of impacted teeth are the major reasons for failure. In addition, the review shows that invasive cervical root resorption (ICRR) is a frequently undiagnosed or unrecognized cause of failure of orthodontic resolution of impacted canines, and should be distinguished from replacement resorption (ankylosis). Corrective measures which may lead to successful treatment are further recommended. Special emphasis is placed on the crucial role of cone beam computerized tomography in the accurate radiographic diagnosis and early detection of pathology of impacted tooth and damage to adjacent anchor teeth. The importance of teamwork in achieving the best treatment outcome is stressed.

The impact of personality on adult patients' adjustability to orthodontic appliances

OBJECTIVE

To evaluate the impact of psychological traits on patients' choice of orthodontic appliances and their adjustability to orthodontic treatment.

MATERIALS AND METHODS

The sample consisted of 68 adult patients divided into three groups (28 buccal, 19 lingual, and 21 clear aligners). Prior to treatment participants filled out the Brief Symptom Inventory to assess symptoms of mental distress and the Narcissistic Vulnerability Scale to assess narcissistic personality traits. During the first week after appliance delivery and on day 14, patients completed a Health-Related Quality of Life questionnaire to assess their perception of pain and four areas of dysfunction. The correlation between personality traits and patients' reaction to treatment was evaluated.

RESULTS

Somatization was the only trait that affected the choice of lingual and clear aligner appliance. Reduced self-esteem regulation was associated with increased pain in all patients, while exploitation was associated with pain in lingual patients. Narcissistic vulnerability slightly influenced patients' adaptability to orthodontic appliances. Although adjustability to lingual appliances was the most difficult, only two parameters were affected by personality features. In the buccal group, adjustability was affected by numerous parameters. Adaptation to the clear aligner appliance was relatively uneventful and least affected by psychological features.

CONCLUSION

Anxious individuals tend to prefer lingual and clear aligner appliances. The selection of lingual and clear aligner appliances governs the patient's response and recovery process, leaving little room for the effect of psychological features. On the other hand, the buccal appliance allows for greater impact of personality traits on adjustability.

Direct recognition of Fusobacterium nucleatum by the NK cell natural cytotoxicity receptor NKp46 aggravates periodontal disease

Periodontitis is a common human chronic inflammatory disease that results in the destruction of the tooth attachment apparatus and tooth loss. Although infections with periopathogenic bacteria such as Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) are essential for inducing periodontitis, the nature and magnitude of the disease is determined by the host's immune response. Here, we investigate the role played by the NK killer receptor NKp46 (NCR1 in mice), in the pathogenesis of periodontitis. Using an oral infection periodontitis model we demonstrate that following F. nucleatum infection no alveolar bone loss is observed in mice deficient for NCR1 expression, whereas around 20% bone loss is observed in wild type mice and in mice infected with P. gingivalis. By using subcutaneous chambers inoculated with F. nucleatum we demonstrate that immune cells, including NK cells, rapidly accumulate in the chambers and that this leads to a fast and transient, NCR1-dependant TNF-α secretion. We further show that both the mouse NCR1 and the human NKp46 bind directly to F. nucleatum and we demonstrate that this binding is sensitive to heat, to proteinase K and to pronase treatments. Finally, we show in vitro that the interaction of NK cells with F. nucleatum leads to an NCR1-dependent secretion of TNF-α. Thus, the present study provides the first evidence that NCR1 and NKp46 directly recognize a periodontal pathogen and that this interaction influences the outcome of F. nucleatum-mediated periodontitis.

Adult patients' adjustability to orthodontic appliances. Part I: a comparison between Labial, Lingual, and Invisalign™

This prospective study examined the adult patient's perception of recovery after insertion of three types of orthodontic appliances: Buccal, Lingual and Invisalign. The sample consisted of sixty-eight adult patients (45 females and 23 males) who comprised three groups: 28 Buccal, 19 Lingual, and 21 Invisalign patients. After appliance insertion, patients completed a Health-Related Quality of Life questionnaire daily for the first week and again on day 14, in order to assess patients' perception of pain and analgesic consumption. In addition, four areas of dysfunction were assessed: oral dysfunction, eating disturbances, general activity parameters, and oral symptoms. Lingual appliance was associated with more severe pain and analgesic consumption, the greatest oral and general dysfunction, and the most difficult and longest recovery. The Invisalign patients complained of relatively high levels of pain in the first days after insertion; however this group was characterized by the lowest level of oral symptoms and by a similar level of general activity disturbances and oral dysfunction compared to the Buccal appliance. Many Lingual and some Buccal patients did not reach a full recovery from their eating difficulties by the end of the study period. The present study provides information to adult patients and clinicians assisting them in choosing the most appropriate treatment modality in relation to Health-Related Quality of Life parameters.

Adult patients' adjustability to orthodontic appliances. Part I: a comparison between Labial, Lingual, and Invisalign™

This prospective study examined the adult patient's perception of recovery after insertion of three types of orthodontic appliances: Buccal, Lingual and Invisalign. The sample consisted of sixty-eight adult patients (45 females and 23 males) who comprised three groups: 28 Buccal, 19 Lingual, and 21 Invisalign patients. After appliance insertion, patients completed a Health-Related Quality of Life questionnaire daily for the first week and again on day 14, in order to assess patients' perception of pain and analgesic consumption. In addition, four areas of dysfunction were assessed: oral dysfunction, eating disturbances, general activity parameters, and oral symptoms. Lingual appliance was associated with more severe pain and analgesic consumption, the greatest oral and general dysfunction, and the most difficult and longest recovery. The Invisalign patients complained of relatively high levels of pain in the first days after insertion; however this group was characterized by the lowest level of oral symptoms and by a similar level of general activity disturbances and oral dysfunction compared to the Buccal appliance. Many Lingual and some Buccal patients did not reach a full recovery from their eating difficulties by the end of the study period. The present study provides information to adult patients and clinicians assisting them in choosing the most appropriate treatment modality in relation to Health-Related Quality of Life parameters.

Orthosurgical treatment including anchorage from a palatal implant to correct an infraoccluded maxillary first molar in a young adult

Tooth ankylosis during adolescence and early adulthood can lead to infraocclusion and several interrelated, adverse sequelae at the intra-arch and interarch levels. An orthosurgical treatment modality that includes surgical luxation and immediate orthodontic traction is recommended as a conservative approach in many patients. The key to success in this approach is the timely delivery of relatively heavy and continuous forces to the luxated tooth to prevent its reankylosis. Because high reactive forces are inevitably generated, it is crucial to create a reliable source of anchorage. This report describes the successful use of an osseointegrated orthodontic implant to reinforce the anchorage during the orthosurgical repositioning of an infraoccluded molar in a young adult.

Saliva enables the antimicrobial activity of LL-37 in the presence of proteases of Porphyromonas gingivalis

Proteolysis is a common microbial virulence mechanism that enables the destruction of host tissue and evasion from host defense mechanisms. Antimicrobial peptides, also known as host defense peptides, are effector molecules of the innate immunity that demonstrate a broad range of antimicrobial and immunoregulatory activities. Deficiency of the human LL-37 antimicrobial peptide was previously correlated with severe periodontal disease. Porphyromonas gingivalis, the major pathogen associated with periodontitis, is highly proteolytic. In this study, P. gingivalis was found capable of degrading LL-37 by utilizing its arginine-specific gingipains. Saliva collected from volunteers with a healthy periodontium protected LL-37 from proteolysis by P. gingivalis. Salivary protection of LL-37 was heat resistant and specific and enabled LL-37 to inhibit growth of Escherichia coli in the presence of the P. gingivalis proteases. Previously, saliva and other body fluids have been shown to inhibit the antimicrobial activity of LL-37. Here we demonstrate that at a cost of a small reduction in the bactericidal activity of LL-37, saliva enables the antibacterial activity of LL-37 despite the presence of proteases secreted by the main periodontopathogen.

Buccal ectopia of maxillary canines with no crowding

INTRODUCTION

Buccally displaced canines (BDC) are usually found in crowded dentitions. Nevertheless, a small but significant number of patients with BDC have no crowding. In this study, we compared BDC dentitions with no crowding (BDC-nc), BDC dentitions with crowding (BDC-c), and uncrowded dentitions with normally erupted canines (C).

METHODS

The mesiodistal (MD) widths of maxillary permanent teeth, the prevalence of maxillary lateral incisor anomalies, and the dental age were compared in BDC-nc (n = 30; 17 male, 13 female), BDC-c (n = 41; 21 male, 20 female), and C dentitions (n = 40; 20 male, 20 female).

RESULTS

No differences in the MD dimensions of the teeth in the BDC-nc and C subjects were found; teeth in the BDC-c group were slightly larger. Only the lateral incisor was consistently smaller in the BDC-nc group. The prevalence of lateral incisor anomalies was markedly increased in the BDC-nc (28.3%) compared with the BDC-c (7.6%) and the C (8.6%) groups. No discrepancies were found in dental age.

CONCLUSIONS

These findings suggest that, in addition to a genetically based etiology, buccal displacement in BDC-nc subjects might also be the result of lack of guidance from an adjacent anomalous lateral incisor.

Malposition of Unerupted Mandibular Second Premolar in Children with Palatally Displaced Canines

Objective: To test the hypotheses that (1) the distal angulation of unerupted mandibular premolar (MnP2) is significantly greater in children with palatally displaced canines (PDC) than in those in a control sample; and (2) delayed tooth formation is significantly more frequent in children with both malposed MnP2 and PDC than in children with PDC only.

Materials and Methods: We examined retrospectively panoramic radiographs from 43 patients with PDC who had no previous orthodontics. A control sample consisted of age- and sex-matched patients. The distal angle formed between the long axis of MnP2 and the tangent to the inferior border was measured. Dental age was evaluated using the Koch classification.

Results: A significant difference was observed between the mean inclination of the right side MnP2 in the PDC group (75.4 degrees) and that of the control group (85.8 degrees). This difference was highly statistically significant (P &lt; .0001). The same evaluation was carried out for the left side, with similar results. The average dental age was found to be delayed in patients who showed both abnormalities (malposed MnP2 and PDC) compared with patients who showed the PDC anomaly only.

Conclusion: Both hypotheses are retained. Statistically, PDC and MnP2 malposition are significantly associated suggesting a common genetic etiology, despite taking place on opposite jaws. While the presence of PDC or MnP2 anomaly has been associated with a delay in tooth formation, we find the presence of both anomalies to show a more profound delay. Our findings suggest a delay in tooth formation as a possible common genetic mechanism for these 2 malposition anomalies.

Orthodontic treatment for the special needs child

The prevalence and severity of malocclusion is especially high in Special Needs individuals. Many have medical limitations to the various procedures that are often needed in the pursuit of excellence from orthodontic treatment and almost all have moderate to severe behavioural problems that make treatment delivery difficult or even impossible to achieve, with any degree of reliability. Nevertheless, the parents are highly motivated to "do the best for their child" and are prepared to become integral members of the treatment delivery team. The present article analyzes the difficulties involved and makes recommendations as to how these may be overcome, based on the authors' published studies in this area and on their broad experience in treating these compromised individuals. Emphasis is placed on the use of pharmacological modalities as the means to providing therapeutic access to many of the more difficult patients. Two case reports are provided to illustrate many of the important principles that pertain to these cases.