Collin Jacobs

Osteogenic differentiation of periodontal fibroblasts is dependent on the strength of mechanical strain

OBJECTIVE During orthodontic therapy the correct strength of mechanical strain plays a key role for bone remodelling during tooth movement. Aim of this study was to investigate the osteogenic differentiation of human periodontal ligament fibroblasts (HPdLF) depending on the applied strength of mechanical strain compared to osteoblasts (HOB). DESIGN HPdLF and HOB were loaded with different strengths (1%, 5% and 10%) of static mechanical strain (SMS) for 12h in vitro. Viability was verified by MTT and apoptosis by TUNEL assay. Gene expression of cyclin D1, collagen type-1 (COL-I), alkaline phosphatase (ALP), osteocalcin, osteoprotegerin (OPG) and receptor activator of the NF-κB ligand (RANKL) were investigated using RT-PCR. OPG and RANKL synthesis was measured by ELISA and ALP activity by colorimetric assay. RESULTS 10% of SMS led to a decrease in cell viability of both cells lines, but no increased rate of apoptosis. RT-PCR showed the highest increase of cyclin D1 expression for HPdLF and HOB when applied to 5% of SMS, and HOB showed a doubling of COL-I gene expression. HPdLF and HOB showed a strength-dependent synthesis of OPG and ALP activity, whereas HOB demonstrated a decrease in OPG synthesis and ALP activity when applied to 10% of SMS. CONCLUSION Osteogenic differentiation of HPdLF correlates with increasing strength of SMS. HOB show decreased activity when applied to high SMS, demonstrating potential damage to the bone remodelling due to strain of high strength. SMS up to 5% provides the best conditions for bone formation at the tension site of tooth movement.

Apical root resorption during orthodontic treatment with aligners? A retrospective radiometric study

IntroductionObjective of this study was to investigate the incidence and severity of apical root resorptions (ARR) during orthodontic treatment with aligners.Materials and methodsThe sample comprised 100 patients (17–75 years of age) with a class I occlusion and anterior crowding before treatment, treated exclusively with aligners (Invisalign®, Align Technologies, Santa Clara, CA, USA). The following teeth were assessed: upper and lower anterior teeth and first molars. Root and crown lengths of a total of 1600 teeth were measured twice in pre- and post-treatment panoramic radiographs. Afterwards, relative changes of the root length during treatment were calculated by a root-crown-ratio taking pre- and post-treatment root and crown lengths into consideration. A reduction of this ratio was considered as a shortening of the initial root length. Additionally, tooth movements of the front teeth were assessed by lateral cephalograms and the 3-dimensonal set up of each patient.ResultsAll patients had a reduction of the pre-treatment root length with a minimum of two teeth. On average 7.36 teeth per patient were affected. 54% of 1600 measured teeth showed no measurable root reduction. A reduction of >0%-10% of the pre-treatment root length was found in 27.75%, a distinct reduction of >10%-20% in 11.94%. 6.31% of all teeth were affected with a considerable reduction of >20%. We found no statistically significant correlation between relative root length changes and the individual tooth, gender, age or sagittal and vertical orthodontic tooth movement; except for extrusion of upper front teeth, which was considered as not clinical relevant due to the small amount of mean 4% ARR.ConclusionsThe present study is the first analyzing ARR in patients with a fully implemented orthodontic treatment with aligners (i.e. resolving anterior crowding). The variety was high and no clinical relevant influence factor could be detected. A minimum of two teeth with a root length reduction was found in every patient. On average, 7.36 teeth per patient were affected.

Current state of orthodontic patients under Bisphosphonate therapy

BackgroundBisphosphonates are a common medication for the prevention and therapy of osteoporosis, but are also applied for tumor diseases. They affect bone metabolism, and therefore also orthodontic treatments, but how it does has yet not been definitively clarified. Therefore, the aim of this research was to evaluate and demonstrate the reported effects and the current state of scientific research regarding orthodontic treatment and bisphosphonate medication exclusively in humans.Material and methodsA systematic research of the literature for selected keywords in the Medline database (Pubmed) as well as a manual search was conducted. The following search terms were used: ‘Bisphosphonate’ in combination with: orthodontic, orthodontic treatment, tooth movement.FindingsTo date, only nine reported patients (case reports/series) and one original article (retrospective cohort study) regarding orthodontic treatment under bisphosphonate medication in humans have been published. Decelerated tooth movement with increased side effects (especially in high-risk patients) and longer treatment duration was reported in some articles. Patients with initial spacing or extraction cases had a higher risk of incomplete space closure and poor root parallelism.ConclusionsOrthodontic tooth movement under bisphosphonate medication is possible, especially in low-risk patients (low dose and short period of intake). But the treatment is still not predictable, especially in high-risk patients. Therefore, the altered bone metabolism and higher extent of side effects should be considered in treatment planning, especially in extraction cases or high-risk patients. Regardless, longer treatment duration, decelerated tooth movement, and more side effects, e.g., incomplete space closure and poor root parallelism, should be expected, especially in extraction cases or space closure.

Effectiveness of maxillary protraction using facemask with or without maxillary expansion: a systematic review and meta-analysis

ObjectivesClass III therapy using a face mask is a common approach for treatment of a deficient maxilla and reverse overbite. Usually, maxillary protraction is combined with transverse palatal expansion using intraoral appliances. The purpose of this study was to systematically review the effectiveness of face mask therapy in combination with concepts of palatal expansion and compression.Material and methodsA systematic review and meta-analysis were performed to identify studies that address class III treatment using a face mask. The search was carried out using common electronic databases as well as hand search. Both screening and study eligibility analysis were performed with consideration of PRISMA and Cochrane Guidelines for systematic reviews. Several terms describing class III face mask treatment were searched. Particular attention was paid to new strategies of enhancing maxillary protraction.ResultsThe initial search identified 2048 studies. After a thorough selection process, a total of 22 articles met the inclusion criteria. After assessment of the individual quality scoring of each article, eight studies were provided for meta-analysis of the cephalometric parameters. The statistical analysis of treatment changes advocates a positive influence on sagittal maxillary development, which is not primarily influenced by transverse expansion. Dental side effects are more distinct when no expansion was carried out. For the concept of alternating activation/deactivation of the expansion appliance (alt-RAMEC), two articles of high methodological scoring were identified. They indicate an enhancement of face mask treatment.ConclusionsThe findings are consistent with results of previous literature studies regarding the efficiency of class III face mask treatment. A further need for more randomized controlled studies was identified especially with regard to the new concept of alternating maxillary expansion and compression, which showed a positive influence on the maxillary protraction based on two studies.Clinical relevanceClass III therapy using extraoral face mask anchorage is effective for maxillary protraction. The recently discussed new protocols potentially improve this treatment.

Bilateral Persistent Trigeminal Arteries, One of Them Ending in the Posterior Inferior Cerebellar Artery

The persistent trigeminal artery (pTA) is the most common embryologic anastomosis between the carotid and vertebrobasilar systems. It was found in 0.1–0.6% in large angiographic series [1]. other persistent embryonic intracranial and extracranial vessels are the hypoglossal and proatlantal arteries. The otic artery, another reported embryologic anastomosis, is a highly controversial artery and presumably does not exist [2]. PTA variants, defined as arteries with direct anastomosis between the intracranial internal carotid artery and the cerebellar arteries, without the interposition of the basilar artery, were found in 0.18% of angiographic studies [3]. However, bilateral pTA is a very rare condition [4, 5]. The case of a patient with bilateral pTA, one of them ending in the posterior inferior cerebellar artery (pICA) is presented. To our knowledge this is the first case reported in the literature with such an anatomic condition. The embryological origin, the Saltzman’s classification and the clinical significance of this uncommon anatomic variation are discussed. Case Report

Endovascular treatment of head and neck arteriovenous malformations: long-term angiographic and quality of life results

Aim To present the long-term angiographic and subjective results of patients with head and neck arteriovenous malformations (HNAVMs) after endovascular treatment. Methods We retrospectively analyzed the medical files of 14 patients with HNAVM who were treated between 2000 and 2014. The treatment of choice was a transarterial superselective microcatheter-based approach followed by embolization using liquid embolic agents. The patients were asked to answer a quality of life questionnaire about the following symptoms before and after treatment: pain, functional impairment, cosmetic deformity, impairment in daily life, and bleeding. Results Complete or >90% closure of the AVM was achieved in 6 of 14 patients (43%). >50% shunt reduction was achieved in 10 patients (71%). Three complications were encountered in a total of 86 interventional procedures. Six patients presented with bleeding which was cured in all cases (100%). Four of the 14 patients (29%) specified pain which was resolved in two of them. Another six patients (43%) presented with functional impairment; four were cured and two noted an improvement. All 14 patients presented with cosmetic concerns; four were cured and eight experienced a clearly visible improvement. Nine of 13 patients (69%) presented with impairment in daily life which was resolved in five patients and four reported an improvement. Conclusions Endovascular embolization is a well-tolerated therapy for HNAVM with a low complication rate. Good angiographic results, positive subjective results, and improvement in different aspects of quality of life can be achieved.

Association between eruption state of the third molar and the occurrence of mandibular angle fractures

BACKGROUND/AIM Fractures of the mandible, especially the mandibular angle, are one of the most frequent types of injuries of the facial skeleton. In many cases, a retained third molar can be found in the line of the fracture. However, it remains unclear whether a relationship between third molars and mandibular angle fractures exists. MATERIALS AND METHODS Patients with isolated or combined fractures of the lower jaw between January 2001 and December 2007 were analyzed retrospectively. Electronic health records were investigated regarding the types of mandibular fractures, and panoramic radiographs were reviewed concerning the existence of third molars. In addition, a systematic review was performed to compare the findings of this study with existing data. RESULTS Six hundred and thirty-two patients were treated for mandibular fractures within the time frame. Two hundred and sixty-seven had a mandibular angle fracture. In 461 patients, panoramic radiographs were available, of which 45.6% did not have a third molar. About 3.8% were edentulous. There is a significant relationship between the existence of unerupted third molars and the occurrence of mandibular angle fractures (P < 0.001). No correlation exists for erupted third molars. CONCLUSIONS Fractures of the mandibular angle are more likely to appear in patients with retained third molars which might be due to the reduced bone mass. Once the wisdom teeth have erupted, the bone structure is more solid and more resistant to external forces and the development of fractures.

A new flash-free orthodontic adhesive system: A first clinical and stereomicroscopic study

OBJECTIVE To analyze the clinical and laboratory properties of the recently introduced APC flash-free orthodontic adhesive. MATERIAL AND METHODS After bonding of 80 brackets on human teeth (group A: APC flash-free adhesive n  =  40, group B: APC Plus adhesive n  =  40), the following measurements were recorded: time for bonding, stereomicroscopic evaluation of excess adhesive, color penetration (methylene blue, 0.5%/24 h), and Adhesive Remnant Index (ARI) score after debonding. RESULTS The time needed for bonding differed significantly between the two groups (A: 19.5 s/tooth vs B: 33.8 s/tooth). The adhesive excess, which was metrically measured from the bracket edge, ranged from 166.27 µm to 81.66 µm (group A) and 988.53 µm to 690.81 µm (group B). After methylene coloration in group A, 52 of 80 measurements showed discoloration on the bracket-adhesive and/or adhesive-enamel interface, while for group B, 78 of 80 were coloration positive. The ARI scores did not differ, with an average ARI score of 2.0 for group A and 2.8 for group B. CONCLUSION The flash-free adhesive significantly reduced the time needed for the bonding process. The excess resin expanded 0.16 to 0.08 mm over the bracket margin. The new technology seems to facilitate a smooth and sufficient marginal surface of the adhesive, which clinically might improve reduction of plaque accumulation.

Delayed and incomplete treatment may result in dural fistula development in children with Vein of Galen malformation

The association of dural arteriovenous fistulas (DAVF) in children with Vein of Galen malformation (VGM) has recently been reported for the first time. In a larger series of cases treated with transarterial NBCA embolization, 30% had DAVF. We wanted to analyze the development of DAVF in our cohort of children with VGM and to evaluate whether their occurrence depends on different treatment timing and embolic materials. We analyzed 43 VGM cases treated with a combined transarterial and transvenous approach between 2003 and 2016. In our early series until 2011, we used coils solely in 21 children. Since 2012, 22 children were treated with the combination of coils and Onyx. In the early series treated with coils solely, no case presented initially with or developed DAVF over time on follow-up angiograms. In our recent series we found four cases (9%) with DAVF. In two patients (5%), DAVF were found on the initial angiogram. Both patients presented at our department at age >2 years and were not treated elsewhere before. One patient (2%) presented at our department with too proximal occlusion of arterial feeders performed at another institution before. Only one patient (2%) developed DAVF in our department after the transarterial use of Onyx. Interestingly, this child did not develop DAVF as long as we used coils solely and his DAVF was localized exactly where an Onyx cast was identified. In conclusion, delayed and incomplete treatment may have a considerable impact on the occurrence of DAVF in VGM.

Die dreidimensionale Optik für den thorakoskopischen ventralen Wirbelkörperersatz – notwendiger Fortschritt oder nur „nice to have“?

BACKGROUND Three-dimensional (3-D) endoscopic optics use 2 cameras to simulate the different perspectives of the right and left eye, creating the illusion of spatial depth. Optimised orientation as well as improved hand-eye coordination compared to 2-D-optics could be proven in standardised test setups (black box) and in laparoscopic use. This retrospective study examines whether these results can also be applied to thoracoscopic vertebral body replacement at the thoracolumbar junction. HYPOTHESES 1. Ventral vertebral body replacement using 3-D-thoracoscopy results in a shorter operation time than with 2-D-thoracoscopy. 2. Perioperative blood loss is less, due to better spatial orientation (faster haemostasis) and reduced tissue laceration. MATERIAL AND METHODS 29 patients met the inclusion criteria of this retrospective study. Between 08 - 2012 and 08 - 2017, all of these received ventral thoracoscopic vertebral replacement at the thoracolumbar junction (Th11 to L2). Patients with additional anterior procedures (e.g. anterolateral plate) were excluded. Perioperative data such as blood loss, duration of surgery and length of hospital stay were analysed. Conventional 2-D-optics were used in n = 14 patients and 3-D-optics in 15 patients. Aesculap EinsteinVision® 2.0 was used as the 3-D-optics. Statistical significance was calculated using Students t-test. RESULTS The most common diagnosis was a L1 fracture (n = 18, 62%). Mean OR time was 24 minutes shorter in the 3-D group (149 ± 29, 107 - 198 min) than in the 2-D group (173 ± 39, 125 - 260 min), but this difference was not significant. Total perioperative blood loss in the 3-D group was significantly lower than in the 2-D group (**p = 0.043). Proportional intraoperative blood loss in the 3-D group was also lower (mean around 115 ml), but not significantly so. Significantly lower values were found for the delivery rate of the thoracic drainage in the 3-D group (248 vs. 560 ml, *p = 0.195). Inpatient stay with the 3-D group was on average 1.5 days (d) shorter (8.7 d for the 3-D group, 10.2 d for the 2-D group) but this difference was not significant (p = 0.27). CONCLUSION Thoracoscopic-assisted vertebral body replacement at the thoracolumbar junction is a safe and reliable surgical procedure using conventional 2-D-optics or the new 3-D-optics. Both methods allow thoracoscopic vertebral body replacement in comparable operation times but in our study the 3-D group presented with significantly lower postoperative blood loss. Due to the small number of cases and because of the retrospective design, the present study is considered to be a pilot study only.