Incisor malalignment and the risk of periodontal disease progression

Computer-Guided Evaluation of the Use of Two Different Devices in the Reduction of Inferior Tooth Crowding

OBJECTIVE

Lower tooth crowding is considered one of the most common malocclusions in growing patients and due to the potential complications associated with it, it is recommended to intercept this condition as soon as possible. The purpose of this paper is to examine and compare the effectiveness of two different orthodontic devices (elastodontic device and clear aligners) in the treatment of anterior tooth crowding in the jaws of young patients.

MATERIALS AND METHODS

Seventy patients aged between 10 and 16 years with anterior inferior tooth crowding were recruited into this study and divided into case and control groups. The former group comprised 35 patients (15 males and 20 females, average age 10.2 years) who were treated with elastodontic devices (EQ CP series, Eptamed), while the control group consisted of 35 patients (15 males and 20 females, average age 10.5 years) who received aligners (Invisalign). All patients underwent periodic visits after 6 months from the start of treatment (T1) and after 1 year (T2) in which the progress of therapy was evaluated by measuring the inferior intercanine distance using a digital caliper. A parametric ANOVA test was conducted for statistical analysis.

RESULTS

There is no statistically significant difference between the two groups at either T1 or T2 (p < 0.05), thus making the two treatment modalities comparable.

CONCLUSIONS

Both elastodontic devices and aligners can be considered as effective tools to successfully conduct inferior expansive treatment for the resolution of tooth crowding; however, the elastodontic devices are considered more comfortable to wear and they are required to be worn for less time during the day.

Expert consensus on pediatric orthodontic therapies of malocclusions in children

Malocclusion, identified by the World Health Organization (WHO) as one of three major oral diseases, profoundly impacts the dental-maxillofacial functions, facial esthetics, and long-term development of ~260 million children in China. Beyond its physical manifestations, malocclusion also significantly influences the psycho-social well-being of these children. Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition, by mitigating the negative impact of abnormal environmental influences on the growth. Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development, ranging from fetal stages to the early permanent dentition phase. From an economic and societal standpoint, the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated, underlining its profound practical and social importance. This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children, emphasizing critical need for early treatment. It elaborates on corresponding core principles and fundamental approaches in early orthodontics, proposing comprehensive guidance for preventive and interceptive orthodontic treatment, serving as a reference for clinicians engaged in early orthodontic treatment.

Reliability of mixed dentition space analysis using a digital model obtained from an optical impression: a preliminary study

OBJECTIVE

While mixed dentition space analysis is a common practice in pediatric dentistry, digital models created using an intraoral scanner are not as widely used in clinical settings. This preliminary study used a very small sample size with one reference model and aimed to (1) compare the accuracy of mixed dentition space analysis using a digital model obtained from an optical impression with that of conventional plaster model-based analysis and (2) assess inter-examiner differences.

RESULTS

The space required for the mandibular permanent canine and premolars and arch length discrepancy were calculated using each model. The largest significant difference between plaster- and digital model-based analyses was identified when the right arch length discrepancy was considered (-0.49 mm; 95% confidence interval: -0.95-0.03); however, the value was considered clinically insignificant. Significant inter-examiner differences were observed for six items of the plaster model; however, no such differences were observed when using the digital model. In conclusion, digital model space analysis may have the same level of accuracy as conventional plaster model analysis and likely results in smaller inter-examiner differences than plaster model analysis.

GDF15 Promotes the Osteogenic Cell Fate of Periodontal Ligament Fibroblasts, thus Affecting Their Mechanobiological Response

Periodontal ligament fibroblasts (PdLFs) exert important functions in oral tissue and bone remodeling following mechanical forces, which are specifically applied during orthodontic tooth movement (OTM). Located between the teeth and the alveolar bone, mechanical stress activates the mechanomodulatory functions of PdLFs including regulating local inflammation and activating further bone-remodeling cells. Previous studies suggested growth differentiation factor 15 (GDF15) as an important pro-inflammatory regulator during the PdLF mechanoresponse. GDF15 exerts its effects through both intracrine signaling and receptor binding, possibly even in an autocrine manner. The extent to which PdLFs are susceptible to extracellular GDF15 has not yet been investigated. Thus, our study aims to examine the influence of GDF15 exposure on the cellular properties of PdLFs and their mechanoresponse, which seems particularly relevant regarding disease- and aging-associated elevated GDF15 serum levels. Therefore, in addition to investigating potential GDF15 receptors, we analyzed its impact on the proliferation, survival, senescence, and differentiation of human PdLFs, demonstrating a pro-osteogenic effect upon long-term stimulation. Furthermore, we observed altered force-related inflammation and impaired osteoclast differentiation. Overall, our data suggest a major impact of extracellular GDF15 on PdLF differentiation and their mechanoresponse.

Use of an antiseptic rinse (NanArgol) for the oral hygiene maintenance of subjects with fixed appliances: A randomized clinical trial

BACKGROUND

The risk of periodontal diseases development increased in patients with malocclusion undergoing orthodontic treatment. Thus, the aim of this study was to examine the efficacy of the use of adjunctive rinses with nano-Argentum to standard oral hygiene regimen in subjects wearing fixed orthodontic appliances.

MATERIALS AND METHODS

Eighty patients were observed for 1 year. They were divided in two groups: in test group patients were instructed to rinse with non-ionic colloidal silver solution according to protocol for 6 months as an adjunct to standard; in control group the patients followed the standard oral hygiene regimen. Index of efficiency of oral hygiene (PHPm), community periodontal index (CPI) and papillary-marginal-alveolar index (PMA) were evaluated before treatment and after 1 and 6 months. For statistics analysis, Mann-Whitney, Kruskal-Wallis tests and Pearson criterion were used.

RESULTS

Baseline hygiene levels in two groups had no differences. Oral hygiene indices were significantly lower in the test group in comparison with control after 1 month (PHPm = 0.38 ± 0.18 and 1.19 ± 0.45, respectively, p < 0.01; PMA = 11.78 ± 8.5 and 47.25 ± 20.9, respectively, p < 0.05; CPI = 0.65 ± 0.53 and 1.53 ± 0.77, respectively, p < 0.01) and 6 months (PHPm = 0.5 ± 0.2 and 1.2 ± 0.4, respectively, p < 0.01; PMA = 11.62 ± 19.6 and 66.33 ± 27.9, respectively, p < 0.01; CPI = 0.63 ± 0.73 and 1.68 ± 0.78, respectively, p < 0.01).

CONCLUSIONS

The use of the test solution as an adjunct to standard oral hygiene provided a significant beneficial effect in terms of oral hygiene in patients undergoing orthodontic treatment.

Impact of PIEZO1-channel on inflammation and osteoclastogenesis mediated via periodontal ligament fibroblasts during mechanical loading

The identification of mechanosensitive ion channels and their importance in innate immunity provides new starting points to elucidate the molecular mechanisms of orthodontic tooth movement. The mechanosensitive electron channel PIEZO1 (Piezo Type Mechanosensitive Ion Channel Component 1) may play a crucial role in orthodontic tooth movement. To investigate the role of the PIEZO1 channel, periodontal ligament fibroblasts (PDLF) were subsequently treated with a PIEZO1 inhibitor (GsMTx) with simultaneous pressure application or with an activator (JEDI2) without mechanical strain. The expression of genes and proteins involved in orthodontic tooth movement was examined by RT-qPCR, Western blot and ELISA. In addition, the effect on PDLF-mediated osteoclastogenesis was investigated in a coculture model using human monocytes. Inhibition of PIEZO1 under pressure application caused a reduction in RANKL (receptor activator of NF-kB ligand) expression, resulting in decreased osteoclastogenesis. On the other hand, activation of PIEZO1 without mechanical strain downregulated OPG (osteoprotegerin), resulting in increased osteoclastogenesis. PIEZO1 appears to play a role in the induction of inflammatory genes. It was also shown to influence osteoclastogenesis.

Impact of Leptin on the Expression Profile of Macrophages during Mechanical Strain In Vitro

Childhood obesity is a growing problem in industrial societies and associated with increased leptin levels in serum and salvia. Orthodontic treatment provokes pressure and tension zones within the periodontal ligament, where, in addition to fibroblasts, macrophages are exposed to these mechanical loadings. Given the increasing number of orthodontic patients with these conditions, insights into the effects of elevated leptin levels on the expression profile of macrophages during mechanical strain are of clinical interest. Therefore, the aim of this in vitro study was to assess the influence of leptin on the expression profile of macrophages during simulated orthodontic treatment. RAW264.7 macrophages were incubated with leptin and lipopolysaccharides (LPS) from Porphyromonas gingivalis (P. gingivalis) or with leptin and different types of mechanical strain (tensile, compressive strain). Expression of inflammatory mediators including tumor necrosis factor (TNF), Interleukin-1-B (IL1B), IL6, and prostaglandin endoperoxide synthase (PTGS2) was assessed by RT-qPCR, ELISAs, and immunoblot. Without additional mechanical loading, leptin increased Tnf, Il1b, Il6, and Ptgs2 mRNA in RAW264.7 macrophages by itself and after stimulation with LPS. However, in combination with tensile or compressive strain, leptin reduced the expression and secretion of these inflammatory factors. By itself and in combination with LPS from P. gingivalis, leptin has a pro-inflammatory effect. Both tensile and compressive strain lead to increased expression of inflammatory genes. In contrast to its effect under control conditions or after LPS treatment, leptin showed an anti-inflammatory phenotype after mechanical stress.

The consequences of living with a severe malocclusion: A review of the literature

AIM

To facilitate the orthognathic shared decision-making process by identifying and applying existing research evidence to establish the potential consequences of living with a severe malocclusion.

METHODS

A comprehensive narrative literature review was conducted to explore the potential complications of severe malocclusion. A systematic electronic literature search of four databases combined with supplementary hand searching identified 1024 articles of interest. A total of 799 articles were included in the narrative literature review, which was divided into 10 themes: Oral Health Related Quality Of Life; Temporomandibular Joint Dysfunction; Masticatory Limitation; Sleep Apnoea; Traumatic Dental Injury; Tooth Surface Loss; Change Over Time; Periodontal Injury; Restorative Difficulty; and Functional Shift and Dual Bite. A deductive approach was used to draw conclusions from the evidence available within each theme.

RESULTS

The narrative literature review established 27 conclusions, indicating that those living with a severe malocclusion may be predisposed to a range of potential consequences. With the exception of Oral Health Related Quality Of Life, which is poorer in adults with severe malocclusion than those with normal occlusions, and the risk of Traumatic Dental Injury, which increases when the overjet is >5 mm in the permanent and 3 mm in the primary dentition, the evidence supporting the remaining conclusions was found to be of low to moderate quality and at high risk of bias.

CONCLUSION

This article summarises the findings of a comprehensive narrative literature review in which all of the relevant research evidence within a substantive investigative area is established and evaluated. Notwithstanding limitations regarding the quality of the available evidence; when combined with clinical expertise and an awareness of individual patient preferences, the conclusions presented may facilitate the orthognathic shared decision-making process and furthermore, may guide the development of the high-quality longitudinal research required to validate them.

Systemic Disorders Closely Associated with Malocclusion in Late Adolescence: A Review and Perspective

Oral diseases such as dental caries and periodontal disease are reported to be associated with various systemic diseases such as heart disease, respiratory disease, diabetes, rheumatism, and metabolic syndrome, thus increasing the importance of prevention and early treatment [...].

Measurement of the morphological data of primary teeth in northwest China

OBJECTIVE

This study aims to digitally obtain the morphological data of children's primary teeth in northwest China and evaluate the reliability of digitally obtaining the anatomical morphological data of primary teeth.

METHODS

A total of 308 extracted primary teeth and cone-beam computed tomography (CBCT) images of 407 primary teeth were collected in northwest China. Electronic digital Vernier callipers (accuracy: 0.01 mm) were used to measure the mesiodistal and buccolingual diameters and crown length of the extracted primary teeth and calculate the crown area and crown index. Each sample was scanned with an intraoral scanner (Trios2 3shape, Denmark), and the resulting stl format files were imported into Geomagic Wrap 2015 to measure the axial and buccolingual diameters and crown length. The crown area and crown index were then calculated. After verifying the accuracy of the CBCT image measurement, the CBCT image data of 407 samples were measured in SmartV software using the "measure length" function by referring to the coronal, sagittal, and horizontal planes to adjust the position of the reference line.

RESULTS

Northern Chinese have larger primary teeth than other populations (Japanese, white American, African, Icelander, Spanish, and Dominican Mestizo) but smaller primary teeth than native Australians. Compared to Indian primary teeth, northwest Chinese's primary teeth have larger diameters on the central axis and smaller diameters on the buccolingual surface. Male teeth are usually larger than female teeth. Compared with the results of Wang Huiyun's study, the axial and buccolingual diameters and crown length of all native tooth types in this total sample were significantly smaller at the 0.1% level, and only the axial diameters of the upper first molar and lower second molar and the crown length of the lower lateral incisor were significantly smaller at the 1% level. The results of the intraclass correlation coefficient of 308 extracted primary teeth expressed an excellent degree of agreement between the callipers and intraoral scanner for the following: mesiodistal diameter (0.956-0.991), buccolingual diameter (0.963-0.989), crown length [0.864-0.992, except for the upper canine (0.690)], crown index (0.850-0.975), and crown area (0.946-0.993).

CONCLUSION

The digital measurements of the intraoral scanner and CBCT image are in good agreement with the manual measurement of the Vernier calliper. The difference between the anatomical morphology size of the primary teeth measured in this study and the results of different populations could be due to different genetic backgrounds and environmental factors.

GDF15 Supports the Inflammatory Response of PdL Fibroblasts Stimulated by P. gingivalis LPS and Concurrent Compression

Periodontitis is characterized by bacterially induced inflammatory destruction of periodontal tissue. This also affects fibroblasts of the human periodontal ligaments (HPdLF), which play a coordinating role in force-induced tissue and alveolar bone remodeling. Excessive inflammation in the oral tissues has been observed with simultaneous stimulation by pathogens and mechanical forces. Recently, elevated levels of growth differentiation factor 15 (GDF15), an immuno-modulatory member of the transforming growth factor (TGFB) superfamily, were detected under periodontitis-like conditions and in force-stressed PdL cells. In view of the pleiotropic effects of GDF15 in various tissues, this study aims to investigate the role of GDF15 in P. gingivalis-related inflammation of HPdLF and its effect on the excessive inflammatory response to concurrent compressive stress. To this end, the expression and secretion of cytokines (IL6, IL8, COX2/PGE2, TNFα) and the activation of THP1 monocytic cells were analyzed in GDF15 siRNA-treated HPdLF stimulated with P. gingivalis lipopolysaccharides alone and in combination with compressive force. GDF15 knockdown significantly reduced cytokine levels and THP1 activation in LPS-stimulated HPdLF, which was less pronounced with additional compressive stress. Overall, our data suggest a pro-inflammatory role for GDF15 in periodontal disease and demonstrate that GDF15 partially modulates the force-induced excessive inflammatory response of PdLF under these conditions.

Effects of histamine and various histamine receptor antagonists on gene expression profiles of macrophages during compressive strain

Purpose

Tissue hormone histamine can accumulate locally within the periodontal ligament via nutrition or may be released during allergic reactions by mast cells, which may have an impact on orthodontic tooth movement. In addition to periodontal ligament fibroblasts, cells of the immune system such as macrophages are exposed to compressive strain. The aim of this study was thus to investigate the impact of histamine on the gene expression profile of macrophages in the context of simulated orthodontic compressive strain.

Methods

Macrophages were incubated with different histamine concentrations (50, 100, 200 µM) for 24 h and then either left untreated or compressed for another 4 h. To assess the role of different histamine receptors, we performed experiments with antagonists for histamine 1 receptor (cetirizine), histamine 2 receptor (ranitidine) and histamine 4 receptor (JNJ7777120) under control and pressure conditions. We tested for lactate dehydrogenase release and analyzed the expression of genes involved in inflammation and bone remodeling by reverse transcription quantitative polymerase chain reaction (RT-qPCR).

Results

Histamine elevated gene expression of tumor necrosis factor under control conditions and in combination with pressure application. Increased prostaglandin-endoperoxide synthase‑2 mRNA was observed when histamine was combined with compressive force. Interleukin‑6 gene expression was not affected by histamine treatment. In macrophages, compressive strain increased osteoprotegerin gene expression. Histamine further elevated this effect. Most of the observed histamine effects were blocked by the histamine 1 receptor antagonist cetirizine.

Conclusions

Histamine has an impact on the gene expression profile of macrophages during compressive strain in vitro, most likely having an impairing effect on orthodontic tooth movement by upregulation of osteoprotegerin expression.

Change in clinical crown height in adult patients treated by means of the multi-bracket appliance with extraction of four first premolars

OBJECTIVE

To evaluate the gingival condition due to adult orthodontic treatment using the clinical crown height (CCH) as an index.

DESIGN

Retrospective study.

SETTING

Department of Orthodontics at a university.

PARTICIPANTS

A total of 21 adult female patients with healthy periodontal tissue were treated by means of the multi-bracket appliance with extraction of four first premolars.

METHODS

Three-dimensional (3D) digital dental models were reconstructed to assess the vertical movement of the free gingival margin caused by adult orthodontic treatment. Pre- and post-treatment CCH were measured, and changes in CCH due to treatment were examined.

RESULTS

The change in CCH by orthodontic treatment was able to be assessed objectively using 3D digital models of the dental casts. In the upper dentition, a significant reduction in CCH was found on the labial and lingual sides of the central incisor, with a mean of -0.28 mm and -0.34 mm, respectively (P < 0.001). In contrast, a significant increase in CCH was found on the labial side of the lateral incisor with a mean of 0.75 mm (P < 0.001). In the lower dentition, CCH on the lingual side of the canine, the second premolar and the first molar increased significantly (P < 0.001), with a mean of 0.41 mm, 0.45 mm and 0.50 mm, respectively. For the buccal side, the second premolar showed a significant increase in CCH with a mean of 0.61 mm (P < 0.001).

CONCLUSION

By using the CCH as an index, it was possible to assess the gingival condition after active orthodontic treatment.

Long-term periodontal changes associated with oral appliance treatment of obstructive sleep apnea

STUDY OBJECTIVES

To characterize the mandibular anterior teeth crown height as a marker of periodontal changes and bone loss as a side effect of an oral appliance (OA) worn for a minimum of 4.5 years.

METHODS

This retrospective study conducted on patients with healthy baseline periodontiu m recruited participants from consecutive sleep apnea patients treated with an OA between 2004 to 2014. Eligible participants were recalled for a follow-up visit where a periodontal exam was performed, a lateral cephalogram and dental impressions were obtained. Clinical crown height for mandibular anterior teeth and cephalometric variables were measured and compared before and after treatment. A full periodontal evaluation was performed at the follow-up visit.

RESULTS

21 patients enrolled with a mean treatment length of 7.9±3.3 years. For the mandibular anterior teeth, clinical crown height did not change over the evaluated period. At follow-up, all the periodontal assessed variables were within normal limits, with the mean probing depth of 1.4±0.5 mm, recession 0.6±1.1 mm and Clinical Attachment Loss (CAL) 0.8±1.0 mm. Compared to baseline, there was a significant proclination of mandibular incisors (mean increase of 5.1°) with the continued use of OA. Gingival levels were maintained with clinically insignificant changes during the observation period.

CONCLUSIONS

Inclination of the mandibular incisors increases significantly with the use of an OA in patients with obstructive sleep apnea (OSA). Positional changes in these teeth were not associated with any measured evidence of increase in clinical crown height or gingival recession.

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.

Close Association between Awareness of Teeth-Alignment Disorder and Systemic Disorders in Late Adolescence

Background: Oral diseases are associated with various systemic disorders. Our previous research revealed new insights into the close relationship between occlusal disorder (functional disorder) and systemic disorders (allergic rhinitis, asthma, and arrhythmia) in late adolescence. Here, we investigated whether there was an association between the awareness of teeth-alignment disorder (morphological disorder) and common systemic disorders. Subjects and Methods: We retrospectively reviewed the data of the mandatory medical questionnaire that is required for the freshman medical checkup in Japan. We collected the data of all students who completed the questionnaire between April 2017 and April 2019. The data were analyzed using the χ² test, and a multivariate analysis was performed with a binomial logistic regression model. Results: The subjects were 8903 students aged 17–19 who had no awareness of occlusal disorder. The rate of awareness of teeth-alignment disorder was 20.43% (1819 of 8903 eligible subjects), and the aware students had significantly greater rates of gum bleeding (p < 0.001), pollinosis (n = 0.007), and atopic dermatitis (n = 0.042). The multivariate analysis revealed significant rates of gum bleeding (odds ratio (OR) 1.540, 95% confidence interval (CI): 1.386–1.711, p < 0.001), pollinosis (OR 1.197, 95% CI: 1.040–1.378, p = 0.012), and female gender (OR 1.141, 95% CI: 1.002–1.299, p = 0.046) among the students with awareness of teeth-alignment disorder. Conclusion: We identified close associations between the awareness of teeth-alignment disorder and both gum bleeding and pollinosis in a late-adolescent population. The systemic disorders that are targeted by teeth-alignment disorder were found to be different from those targeted by occlusal disorder.

The role of HIF-1α in nicotine-induced root and bone resorption during orthodontic tooth movement

BACKGROUND

In orthodontic tooth movement (OTM), pseudo-inflammatory processes occur that are similar to those of nicotine-induced periodontitis. Previous studies have shown that nicotine accelerates OTM, but induces periodontal bone loss and dental root resorption via synergistically increased osteoclastogenesis. This study aimed to investigate the role of hypoxia-inducible factor 1 alpha (HIF-1α) in nicotine-induced osteoclastogenesis during OTM.

MATERIALS/METHODS

Male Fischer-344 rats were treated with l-Nicotine (1.89 mg/kg/day s.c., N = 10) or NaCl solution (N = 10). After a week of premedication, a NiTi spring was inserted to mesialize the first upper left molar. The extent of dental root resorption, osteoclastogenesis, and HIF-1α protein expression was determined by (immuno)histology, as well as bone volume (BV/TV) and trabecular thickness (TbTh) using µCT. Receptor activator of nuclear factor of activated B-cells ligand (RANK-L), osteoprotegerin (OPG), and HIF-1α expression were examined at the protein level in periodontal ligament fibroblasts (PDLF) exposed to pressure, nicotine and/or hypoxia, as well as PDLF-induced osteoclastogenesis in co-culture experiments with osteoclast progenitor cells.

RESULTS

Nicotine favoured dental root resorptions and osteoclastogenesis during OTM, while BV/TV and TbTh were only influenced by force. This nicotine-induced increase does not appear to be mediated by HIF-1α, since HIF-1α was stabilized by force application and hypoxia, but not by nicotine. The in vitro data showed that the hypoxia-induced increase in RANK-L/OPG expression ratio and PDLF-mediated osteoclastogenesis was less pronounced than the nicotine-induced increase.

CONCLUSIONS

Study results indicate that the nicotine-induced increase in osteoclastogenesis and periodontal bone resorption during OTM may not be mediated by hypoxic effects or HIF-1α stabilization in the context of nicotine-induced vasoconstriction, but rather by an alternative mechanism.

Impact of NSAID etoricoxib on side effects of orthodontic tooth movement

OBJECTIVES

The non-steroidal anti-inflammatory drug etoricoxib is the most highly selective inhibitor of cyclooxygenase-2 available (344:1) and has been approved for postoperative pain therapy following dental interventions in Europe. At clinically relevant doses it has been reported to only have marginal effects on the velocity of orthodontic tooth movement (OTM). Its effects on associated dental root resorptions, osteoclastogenesis, trabecular number in the alveolar bone and periodontal bone loss during OTM, however, have not yet been investigated.

MATERIAL AND METHODS

40 male Fischer344 rats were divided into four groups: 1.5ml tap water/day p.o. (control, 1), additional 7.8mg/kg/day etoricoxib (normal dose) for three (2) or seven (3) days/week and 13.1mg/kg/day (high dose) for seven days/week, respectively (4). After a week of premedication, OTM in anterior direction of the first left upper molar was performed for 28 days by means of a nickel-titanium coil spring (0.25N). We quantified OTM-associated dental root resorptions, osteoclastogenesis, trabecular number and periodontal bone loss by histomorphometrical, histochemical and μCT analyses of the disected tooth-bearing upper jaw sections.

RESULTS

After 28 days of OTM, associated reduction of trabecular number seemed to be slightly alleviated by high doses of etoricoxib, whereas no significant other etoricoxib effects in the doses administered could be detected regarding OTM-induced or -associated dental root resorptions, osteoclastogenesis or periodontal bone loss.

CONCLUSIONS

Dental root resorptions, osteoclastogenesis and periodontal bone loss during OTM in rats were not significantly affected by etoricoxib in the clinically relevant dosages investigated with only a slight inhibitory effect on bone remodelling to be expected at high dosages. Etoricoxib is therefore not suitable for the prevention of these detrimental effects, but could be a suitable analgesic during OTM, as it has been reported not to affect tooth movement.

Relationship between Malocclusion and Periodontal Disease in Patients Seeking Orthodontic Treatment in Southwestern Saudi Arabia

Background:

Malocclusion is known to cause plaque accumulation and periodontal breakdown. However, no previous study from Saudi Arabia has assessed this relationship in patients seeking orthodontic treatment for esthetics.

Objective:

The objective of this study was to investigate the relationship between malocclusion and periodontal disease in terms of gingival inflammation, probing pocket depth (PPD) and recession in patients seeking orthodontic treatment for esthetic improvement.

Materials and Methods:

This prospective cross-sectional study was conducted at the Outpatient Division of Periodontics, College of Dentistry, King Khalid University, Saudi Arabia, among consecutive new patients seeking orthodontic treatment for esthetic improvement between June and August 2018. Angle’s class of malocclusion, various malalignments, plaque index (PI), gingival index (GI), adequacy of width of attached gingiva (WAG), response to fremitus test, PPD and gingival recession (GR) were recorded. P < 0.05 was considered statistically significant.

Results:

A total of 410 consecutive patients were included. Of these, 314 patients had Class I, 57 had Class II (division I), 25 had Class II (division II) and 14 had Class III malocclusions. In patients with all types of malocclusion, the majority had a PI and GI of score 2 (74.1% and 83.7%, respectively). Most of the patients (85.9%) had adequate WAG; similarly, 94.9% had a negative fremitus test, which shows the absence of trauma from occlusion. Mean PPD and GR in the maxillary and mandibular arches showed varying results.

Conclusion:

This study demonstrates a relationship between malocclusion and presence of periodontal disease in patients seeking orthodontic treatment for esthetic improvement in the southwestern region of Saudi Arabia. Therefore, in patients seeking orthodontic treatment, careful evaluation of gingival and oral hygiene along with adequacy of attached gingiva should be considered.

Biomechanical analysis of initial incisor crowding alignment in the periodontally reduced mandible using the finite element method

AIMS

To reduce remaining plaque niches due to dental malocclusion after periodontal treatment and to avoid reinflammation of periodontitis, severe anterior crowding can be treated orthodontically. The treatment indication is motivated by aesthetic and functional needs. In this study the biomechanical behaviour of crowded lower front teeth in reduced periodontium is analysed.

METHODS

Using the finite element (FE) method, a model of the mandible was constructed with an anterior crowding of 4 mm and a vertical bone loss of 4 mm in the front tooth area. A 0.3 mm (0.012″) round superelastic nickel titanium (NiTi) arch wire was fitted to an ideal positioned teeth set-up and was inserted into the brackets of teeth 34 to 44 in the crowded model. The premolars were used as the anchorage unit. Material parameters were adopted from previous investigations, including bone (homogenous, isotropic, E = 2 GPa), teeth (E = 20 GPa) and healthy periodontal ligament (PDL, bilinear elastic; E₁ = 0.05 MPa; E₂ = 0.2 MPa; ε₁₂ = 7%). All simulations were compared to simulations with a physiological periodontal model to assess the effect of bone loss at teeth 42 to 32. Additionally, the influence of three arch wire materials (nonsuperelastic NiTi, superelastic NiTi and stainless steel) were analysed in a reduced model, including only brackets in position of the crowded front teeth, wire and ligatures. Wire force levels and stresses were determined to assess the influence of material variation.

RESULTS

Initial tooth mobility is increased by a factor of 2.5 in case of a moderate periodontal defect. Front teeth with reduced attachment display increased strains in the periodontal ligament up to a factor of 2. Forces in the model with reduced periodontium were decreased by a factor of 2. Comparing different aligning arch wires, stainless steel appears to have the highest force and stress levels. Force levels of this alloy were 7.5 times higher than with the superelastic NiTi wire. Force levels of nonsuperelastic NiTi appeared to be 1.8 times higher than superelastic NiTi. Calculated stresses with stainless steel were 5 times higher than with the nonsuperelastic NiTi and 10 times higher than with superelastic NiTi.

CONCLUSION

Periodontally reduced incisors 42 to 32 are associated with an increased load on periodontal tissue and increased level of tooth mobility during fixed orthodontic treatment. This has to be considered by reducing orthodontic force levels and by selecting mechanics that reduce the load to the tissue.

Effects of the Highly COX-2-Selective Analgesic NSAID Etoricoxib on Human Periodontal Ligament Fibroblasts during Compressive Orthodontic Mechanical Strain

Human periodontal ligament (hPDL) fibroblasts play a major role during periodontitis and orthodontic tooth movement, mediating periodontal inflammation, osteoclastogenesis, and collagen synthesis. The highly COX-2-selective NSAID etoricoxib has a favorable systemic side effect profile and high analgesic efficacy, particularly for orthodontic pain. In this in vitro study, we investigated possible side effects of two clinically relevant etoricoxib concentrations on the expression pattern of mechanically strained hPDL fibroblasts and associated osteoclastogenesis in a model of simulated orthodontic compressive strain occurring during orthodontic tooth movement. hPDL fibroblasts were incubated for 72 h under physiological conditions with etoricoxib at 0 μM, 3.29 μM, and 5.49 μM, corresponding to clinically normal and subtoxic dosages, with and without mechanical strain by compression (2 g/cm²) for the final 48 h, simulating conditions during orthodontic tooth movement in compressive areas of the periodontal ligament. We then determined gene and/or protein expression of COX-2, IL-6, PG-E₂, RANK-L, OPG, ALPL, VEGF-A, P4HA1, COL1A2, and FN1 via RT-qPCR, ELISA, and Western blot analyses as well as apoptosis, necrosis, cell viability, and cytotoxicity via FACS, MTT, and LDH assays. In addition, hPDL fibroblast-mediated osteoclastogenesis was assessed by TRAP staining in coculture with RAW267.4 cells for another 72 h. Gene and protein expression of all evaluated factors was significantly induced by the mechanical compressive strain applied. Etoricoxib at 3.29 μM and 5.49 μM significantly inhibited PG-E₂ synthesis, but not COX-2 and IL-6 gene expression nor RANK-L-/OPG-mediated osteoclastogenesis or angiogenesis (VEGF-A). Extracellular matrix remodeling (COL1A2, FN1) and bone anabolism (ALPL), by contrast, were significantly stimulated particularly at 5.49 μM. In general, no adverse etoricoxib effects on hPDL fibroblasts regarding apoptosis, necrosis, cell viability, or cytotoxicity were detected. Clinically dosed etoricoxib, that is, a highly selective COX-2 inhibition, did not have substantial effects on hPDL fibroblast-mediated periodontal inflammation, extracellular matrix remodeling, RANK-L/OPG expression, and osteoclastogenesis during simulated orthodontic compressive strain.

Effects of the highly COX-2-selective analgesic NSAID etoricoxib on the rate of orthodontic tooth movement and cranial growth

BACKGROUND

NSAID analgesics have found widespread use in the treatment of pain, inflammation and fever. The highly COX-2-selective NSAID etoricoxib has shown a favorable side effect profile and excellent analgesic efficacy, particularly for dental and orthodontic pain, surpassing the current standard analgesic in orthodontics, acetaminophen. However, potential side effects on the rate of orthodontic tooth movement (OTM) and cranial growth, relevant for clinical usability during orthodontic treatment, have not yet been investigated.

MATERIAL AND METHODS

40 male Fischer344 rats were randomly assigned to 4 groups (n=10) - controls receiving only 1.5ml tap water per day by oral gavage for a total of 5 weeks (1) as well as rats receiving an additional daily normal etoricoxib dosage of 7.8mg/kg for 3d (2) and 7d/week (3) and a high dosage of 13.1mg/kg for 7d/week (4) with serum bioavailability assessed by liquid chromatography-mass spectrometry. After one week of premedication, the first upper left molars (M1) were moved orthodontically in anterior direction for 4 weeks using a closed NiTi coil spring (0.25N) and OTM as well as sagittal cranial growth were quantified cephalometrically by CBCT imaging at the start and end of OTM.

RESULTS

OTM, quantified as anterior metric tipping of M1, was significantly inhibited by about 33% only in rats receiving high-dose etoricoxib 7d/week (p=0.046) with a respective, but insignificant tendency also detectable for the normal dosages, whereas sagittal cranial growth was by tendency slightly increased with rising etoricoxib dosages, reflected by corresponding steady-state serum concentrations, confirming etoricoxib bioavailability.

CONCLUSIONS

An etoricoxib-induced clinically relevant deceleration of OTM is not to be expected at dosage regimens used in clinical practice to treat dental or orthodontic pain in contrast to a continuously administered high dosage. Due to its favorable side effect profile and higher analgesic efficiency regarding dental and orthodontic pain, etoricoxib should be a clinically valid alternative to the current standard orthodontic analgesic acetaminophen with its associated higher risk profile.

Influence on interradicular bone volume of Invisalign treatment for adult crowding with interproximal enamel reduction: a retrospective three-dimensional cone-beam computed tomography study

BACKGROUND

The aim of this study was to use three-dimensional datasets to identify associations between treatment for adult crowding, using Invisalign aligner and interproximal enamel reduction (IER), and changes in the volume of interradicular bone.

METHODS

A total of 60 cone-beam computed tomography (CBCT) scans from 30 adult patients (28 women, two men; 30 CBCTs pre-treatment, 30 post-treatment) were examined retrospectively in order to measure bone volume three-dimensionally. The patients' average age was 36.03 ± 9.7 years. The interradicular bone volume was measured with OsiriX at four levels in the anterior tooth areas of the maxilla and mandible. Differences in bone between T0 and T1 were analyzed with IBM SPSS 21.0 using the Wilcoxon test for paired samples.

RESULTS

Overall, a slight increase in the quantity of bone was found (0.12 ± 0.73 mm). There was a highly significant increase in bone in the mandible (0.40 ± 0.62 mm; P <  0.001), while in the maxilla there was a slight loss of bone, which was highly significant in the apical third (- 0.16 ± 0.77 mm; P = 0.001).

CONCLUSIONS

Overall, treatment for adult crowding using an aligner and IER appears to have a positive effect on interradicular bone volume, particularly in patients with severe grades of the condition (periodontally high-risk dentition). This effect is apparently independent of IER. This is extremely important with regard to the treatment outcome, since IER and root proximity have been matters of debate in the literature and teeth should remain firmly embedded in their alveolar sockets.