Search

Purpose: It is thought that orthodontic forces initially reduce periodontal blood flow during orthodontic tooth movement (OTM) via tissue compression with cells responding to concomitant oxygen deprivation with expression of vascular endothelial growth factor (VEGF) triggering angiogenesis via binding to its receptor VEGFR‑2. To test this hypothesis, we performed a pilot study to establish a protocol for molecular magnetic resonance imaging (MRI) of rat jaws administering a VEGFR-2-specific contrast agent., Methods: Mesial OTM of a first upper left rat molar was initiated in one male Fischer 344 rat 4 days prior to MRI by insertion of an elastic band between the first and second upper molars with the contralateral side left untreated (internal control). T1-weighted MRI sequences including dynamic contrast-enhanced MRI (DCE-MRI) were recorded before and after administration of a molecular VEGFR‑2 MRI marker with a 7 T MRI dedicated for small animal use., Results: After injection of anti-VEGFR2-albumin-gadolinium-DTPA, volume enhancement on T1-weighted images was increased at the OTM side distally of the moved first upper molar (M1) compared to the control side, whereas the T1 relaxation time was reduced on the OTM side. DCE-MRI resulted in an increased area under the curve (AUC), whereas time-to-peak (TTP) and washout rate were reduced during OTM distally of the moved M1 compared to the contralateral side., Conclusions: OTM resulted in uptake of the VEGFR-2-specific MRI contrast agent in tension areas of the periodontal ligament. The imaging protocol presented here is useful for the assessment of VEGFR‑2 expression in tension areas of the periodontal ligament in vivo., (© 2021. The Author(s).)

Objective: Gingival invaginations are a common side effect of orthodontic extraction-space closure. The timing of initiating the closure of an extraction space varies greatly in clinical practice. In this multicenter pilot and randomized controlled trial, we prospectively investigated whether initiating space closure in the early stage of wound healing would benefit the incidence and severity of invaginations developing in the extraction sites., Methods: A total of 368 patients were screened for indications to extract at least one mandibular premolar. Those recruited were randomly assigned to one of two treatment arms: initiation of space closure either 2-4 weeks (arm A) or ≥12 weeks (arm B) after tooth extraction. Clinical data regarding treatment process and periodontal tissue response were recorded during and after space closure and analyzed by a specialized biometrics unit. The study was performed under continuous surveillance by an independent study control center., Results: A total of 74 extraction sites were analyzed. Regarding the incidence of gingival invaginations, there were no significant intergroup differences [p = 0.13; group A comprising 37/44 (84.1%) and group B 29/30 (96.7%) invaginated sites]. The same was true based on either maxillary (p = 0.52) or mandibular (p = 0.21) sites only, and the severity of the invaginations did not differ between the treatment arms., Conclusions: As to the incidence and severity of gingival invaginations, we did not notice any statistically significant differences between the two timeframes. Our data do, however, provide a basis to identify additional confounders and to improve the accuracy of case-load estimations for future trials.

Objective: Orthodontic appliances are considered to be highly biocompatible although adverse effects attributed to the release of nickel ions (Ni(2+)) have been documented. Self-ligating brackets have grown in popularity for economic reasons and supposed friction reduction. The aim of the present prospective cohort study was therefore to determine salivary Ni(2+) concentrations in patients undergoing orthodontic treatment with self-ligating fixed appliances., Materials and Methods: A group of 30 patients between 10 and 13 years of age were treated with self-ligating brackets (SmartClip™), molar bands, and nickel-titanium (NiTi) archwires. Unstimulated saliva samples were collected after different time points (before treatment, after self-ligating bracket and band placement, before archwire insertion, after archwire insertion, and finally 4 and 8 weeks afterwards) and analyzed with an ICP mass spectrometer followed by generalized estimating equation modelling with α = 5 %., Results: The baseline median salivary Ni(2+) concentration was 21.85 µg/l, while the Ni(2+) concentrations at the following visits ranged between 13.73 and 85.34 µg/l. Significant increases in Ni(2+) levels compared to the baseline levels were detected after band/bracket placement [+59.76 µg/l; 95 % confidence interval (CI) 44.88-74.64 µg/l; P < 0.001] and after archwire insertion (+53.55 µg/l; 95 % CI 25.57-81.52 µg/l; P < 0.001). After 4 weeks, Ni(2+) concentrations returned to initial control levels or were lower., Conclusion: Self-ligating orthodontic appliances may affect salivary Ni(2+) concentrations in vivo over the short term. However, levels resembled those documented in conjunction with conventional bracket use and remained below the daily dietary Ni intake.

The Hutchinson-Gilford progeria syndrome (HGPS) is an exceptionally rare medical disorder caused by mutations in the lamin A/C gene. Affected patients display typical features of premature aging. Beside general medical disorders, these patients have several specific features related to the craniofacial phenotype and the oral cavity. In this article, the dental and craniofacial characteristics of a 9-year-old girl with HGPS are presented. It is the first report addressing orthodontic tooth movement and microbiological features in a HGPS patient. We describe and discuss pathologic findings and provide a detailed histology of the teeth which had to be extracted during initial treatment.

Background and Objective: Gingival invaginations are a frequent finding during tooth extraction and following orthodontic space closure. Based on the interdental localization and sometimes pronounced depth, it has been suggested that a gingival invagination may impede oral hygiene. In Part I of this series, the time until active tooth movement and the localization of extraction were identified as potential risk factors for the development of gingival invagination. The aims of the present study were the analysis of the microbial spectrum of a gingival invagination in comparison with pool samples of the sulcus of Ramfjord teeth, on the one hand, and the importance of genetic variations of the pro-inflammatory mediator interleukin-1 (IL-1) and its receptor antagonist (IL-1-RN), on the other hand. In addition, a possible role of smoking as a risk factor was evaluated., Subjects and Methods: A total of 30 patients with (n=16) and without (n=14) gingival invagination were examined for the presence of eleven periodontal pathogen bacterial species with a commercially available test (micro-IDent®Plus, Hain Lifescience, Nehren, Germany). The genetic evaluation was performed with the GenoType® IL-1 test (Hain Lifescience)., Results: The results of the microbiological analysis of gingival invaginations showed that the bacterial flora might differ or even be higher than the pool sample from sulcus regions. The genetic evaluation demonstrated that in the group without gingival invagination only 14% showed an IL-1 polymorphism, whereas this value was twice as high (35%) in the group with gingival invagination. In addition, a combination of both polymorphisms IL-1 and IL-1-RN was only found in patients with gingival invagination (25%). Interestingly, smoking patients showed a significant increase of the severity of the gingival invagination., Conclusion: This retrospective study demonstrated that gingival invagination might be accompanied with an altered microbiological bacterial spectrum and a genetic IL-1 polymorphism. In addition, smoking was identified as another potential risk factor for the severity of gingival invaginations.

Many orthodontic treatments involve tooth extraction. Gingival invagination is a common side effect after orthodontic extraction space closure leading to compromised oral hygiene and the space closure being hampered. Even the long-term stability of the orthodontic treatment result may be jeopardized. The aim of this study was to identify risk factors for the development of gingival invagination and possible implications on oral health and orthodontic treatment results.A total of 30 patients presenting 101 tooth extractions and subsequent orthodontic space closure were investigated to detect the presence of gingival invagination. The time required until active space closure, the thoroughness of space closure, and probing depths mesial and distal to the extraction site in addition to age, gender and the Periodontal Screening Index were investigated. A new coding system to describe the extent of gingival invagination is introduced for the first time here.Gingival invagination developed more frequently in the lower jaw (50%) than the upper (30%). Complete penetration occurred in the upper jaw in 6% of the patients and in the lower jaw in 25%. All patients without gingival invagination revealed complete space closure, whereas only 70% in the group with gingival invagination did so. The time until initiation of space closure took significantly longer in patients with gingival invagination (7.5 ± 1.4 months) than in patients without (3.3 ± 0.8 months). Probing depths of the adjacent teeth were significantly greater in regions with invaginations.Thus, the time required until space closure was initiated and the extraction site are important risk factors for the development of gingival invagination. The consequences of gingival invagination are instable space closure and deeper probing depths mesial and distal to the extractions. However, no statements concerning the mid- to long-term effects on oral health can be made.

Gingival invagination is an alteration of the ginviva often observed during orthodontic space closure. This finding appears as a "pseudopocket" which can be probed both horizontally and vertically. The objective of this systematic literature review was to present information on the etiology and intermediate and long-term sequelae of gingival invagination, together with possible approaches to its prevention and treatment. To find currently available literature a MeSH term search in the PubMed literature database was carried out, complemented by manual search in selected dental journals and in the reference lists of the identified articles. Only few articles on gingival invagination were identified. Those that were found displayed different levels of evidence which made a quantitative evaluation impossible. The results are summarized and discussed in light of this information.