Lina Gölz

Imputation of Orofacial Clefting Data Identifies Novel Risk Loci and Sheds Light on the Genetic Background of Cleft Lip ± Cleft Palate and Cleft Palate Only.

Abstract Nonsyndromic cleft lip with or without cleft palate (nsCL/P) is among the most common human birth defects with multifactorial etiology. Here, we present results from a genome-wide imputation study of nsCL/P in which, after adding replication cohort data, four novel risk loci for nsCL/P are identified (at chromosomal regions 2p21, 14q22, 15q24 and 19p13). On a systematic level, we show that the association signals within this high-density dataset are enriched in functionally-relevant genomic regions that are active in both human neural crest cells (hNCC) and mouse embryonic craniofacial tissue. This enrichment is also detectable in hNCC regions primed for later activity. Using GCTA analyses, we suggest that 30% of the estimated variance in risk for nsCL/P in the European population can be attributed to common variants, with 25.5% contributed to by the 24 risk loci known to date. For each of these, we identify credible SNPs using a Bayesian refinement approach, with two loci harbouring only one probable causal variant. Finally, we demonstrate that there is no polygenic component of nsCL/P detectable that is shared with nonsyndromic cleft palate only (nsCPO). Our data suggest that, while common variants are strongly contributing to risk for nsCL/P, they do not seem to be involved in nsCPO which might be more often caused by rare deleterious variants. Our study generates novel insights into both nsCL/P and nsCPO etiology and provides a systematic framework for research into craniofacial development and malformation.

Lingual vs. labial fixed orthodontic appliances: systematic review and meta-analysis of treatment effects

The aim of this systematic review was to compare the therapeutic and adverse effects of lingual and labial orthodontic fixed appliances from clinical trials on human patients in an evidence-based manner. Randomized and prospective non-randomized clinical trials comparing lingual and labial appliances were included. Risk of bias within and across studies was assessed using the Cochrane tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Random-effects meta-analyses were conducted, followed by subgroup and sensitivity analyses. Six electronic databases were searched from inception to July 2015, without limitations. A total of 13 papers pertaining to 11 clinical trials were included with a total of 407 (34% male/66% female) patients. Compared with labial appliances, lingual appliances were associated with increased overall oral discomfort, increased speech impediment (measured using auditory analysis), worse speech performance assessed by laypersons, increased eating difficulty, and decreased intermolar width. On the other hand, lingual appliances were associated with increased intercanine width and significantly decreased anchorage loss of the maxillary first molar during space closure. Based on existing trials, there is insufficient evidence to make robust recommendations for lingual fixed orthodontic appliances regarding their therapeutic or adverse effects, as the quality of evidence was low.

Nonsyndromic cleft lip with or without cleft palate in arab populations: Genetic analysis of 15 risk loci in a novel case–control sample recruited in Yemen

BACKGROUND Nonsyndromic orofacial clefting (nsOFC) is among the most common of all congenital disorders and has a genetically complex etiology. Based on embryological and epidemiological data, the phenotype can be differentiated into nonsyndromic cleft lip with or without cleft palate (nsCL/P) and nonsyndromic cleft palate only, with nsCL/P being the most frequent form. Recent genetic research, predominantly performed in populations from Europe and Asia, has identified numerous genetic susceptibility loci for nsCL/P. As only few data are available concerning genetic susceptibility to nsCL/P in Arab populations, we investigated a newly recruited nsOFC sample from Yemen. METHODS For each of the 15 currently known nsCL/P risk loci, the top single-nucleotide polymorphism (plus nine back-up variants) were genotyped in 242 nsCL/P cases and 420 healthy controls. RESULTS Single-marker association analysis revealed significant associations for four loci (8q24, 9q22, 10q25, 13q31). The strongest association was for the European high risk locus at 8q24 (Pcorrected  = 5.09 × 10(-4) ; heterozygous odds ratio = 1.74 (1.22-2.47), homozygous odds ratio = 2.47 (1.55-3.93). Five additional loci (1q32.2, 3q12, 8q21, 17q22, 20q12) showed nominal significance that did not withstand correction for multiple testing. Although the six remaining loci (1p22, 1p36, 2p21, 3p11, 15q22, 17p13) failed to reach nominal significance, the risk alleles were in the same direction as in the discovery studies. CONCLUSION The results suggest that four of the 15 analyzed nsCL/P risk loci which were identified in European and Asian ethnicities significantly confer risk for nsCL/P in Arab populations.

Wear of double crown systems: electroplated vs. casted female part

Objectives The wear of telescopic crowns is a common problem often reducing the patients satisfaction with the denture and resulting in a renewal of the denture. The study aims to compare the wear behavior of conical crowns using electroplated copings (group E) with standard telescopic crowns with cast female parts (group C). Material and Methods 10 conical crowns were milled for each group of a cast gold alloy. The specimen of group E had a conicity of 2º. The cast secondary crowns of group C had a 0º design. The electroplated coping was established by direct electroforming. An apparatus accomplishing 10,000 wear cycles performed the wear test. The retentive forces and the correlating distance during insertion and separation were measured. The wear test was separated in a start phase, an initial wear phase and the long term wear period. The retention force value and the force-distance integral of the first 0.33 mm of each cycle were calculated. Results The retentive forces were significantly higher for group E and the integrals were significantly lower for this group except the integral at cycle 10,000. The changes of retention force and integral did not differ significantly between both groups in all phases. The change of the integrals as well as the integral at the particular cycles showed higher interquartile distances for group C. Conclusions Within the limitations of this study the tested conical crowns showed clinically acceptable retentive properties. The values reached a range comparable to retentive elements tested in recent literature. The values of group C showed higher ranges. The force measured for group E was significantly higher than for group C but the integrals showed an opposite tendency. The results indicate that an exclusive analysis of the force is not sufficient as the integral is not equivalent to the force although it describes the retentive property of the system in a better way than the force over a distance is described. Both systems seem to be suitable for clinical practice.

Gingival invagination--a systematic review.

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.ZusammenfassungDie Gingivaduplikatur ist eine Veränderung der Schleimhaut, welche oftmals im Laufe eines kieferorthopädischen Lückenschlusses zu beobachten ist. Eine solche Gingivaduplikatur stellt sich als eine Art „Pseudotasche“ dar, die horizontale und vertikale Sondierungstiefen aufweist. Ziel der vorliegenden systematischen Literaturübersicht war es, genauere Hinweise zur Ätiologie, mittel- und langfristigen Folgen sowie zu Ansätzen für die Vermeidung und Therapie von Gingivaduplikaturen zu erhalten. Eine Schlagwortsuche in der Literaturdatenbank „Pubmed“, manuelle Recherche in zahnmedizinischen Zeitschriften sowie eine weitere Recherche in den Quellen der resultierenden Publikationen wurden vorgenommen, um die derzeit verfügbare Literatur zu identifizieren. Die Literaturrecherche ergab nur eine geringe Anzahl an Publikationen zur jeweiligen Fragestellung mit unterschiedlichen Evidenzgraden, die eine quantifizierbare Verwertung der Publikationen nicht zuließen. Aus diesem Grund wurden die Ergebnisse entsprechend der genannten Fragestellung zusammengefasst und diskutiert.

Possible implications of Ni(II) on oral IL-1β-induced inflammatory processes

OBJECTIVES Nickel (Ni) is one of the main metal elements in orthodontic and prosthetic devices. Different effects of Ni are described ranging from an induction of local inflammation to allergy and cancerous/mutagenic properties. Inflammatory reactions are frequently observed in the oral cavity, but the interrelationship of Ni with those events is still unknown. Therefore, we focused on the impact of Ni on inflammation in vitro. METHODS In accordance to previous immersion tests of our lab, human gingival fibroblasts (HGFs) (n=6) were exposed to a pro-inflammatory environment using interleukin-1 beta (IL-1β) and additionally stimulated with different Ni(II) concentrations (400 and 4000ng/ml). At varying time points the expression of pro- and anti-inflammatory as well as matrix degeneration proteins, i.e. MMPs, were analyzed. Furthermore, proliferation assays, wound healing tests and the detection of NF-κB activation were conducted. Unstimulated HGFs served as control. RESULTS Our experiments showed that low clinical average Ni(II) levels did not alter pro-inflammatory cytokines significantly compared to control (p>0.05). Instead, a 10-fold higher dose up-regulated these mediators significantly in a time-dependent manner (p<0.01). This was even more pronounced combining both Ni(II) concentrations with an inflammatory condition (p<0.001), MMP expressions were in line with our findings (p<0.001). The mRNA data were supported by proliferation and wound closure assays (p<0.001). However, the combination of both stimuli induced contradictory results. Analyzing NF-κB activation revealed that our results may be in part attributed to NF-κB. SIGNIFICANCE Our in vitro study implicated that Ni(II) has various modifying effects on IL-1β-induced inflammatory processes depending on the concentration.

Nickel hypersensitivity and orthodontic treatment: a systematic review and meta‐analysis

Nickel‐containing alloys are widely used in orthodontic appliances, even though nickel is by far the most common contact allergen. However, the scientific evidence concerning allergic reactions to nickel in orthodontic patients has not been evaluated systematically. The objective of this study was to investigate whether the prevalence of nickel hypersensitivity is affected by orthodontic treatment. Unrestricted electronic and manual searches were performed until July 2013 for human clinical studies assessing orthodontic treatment and nickel hypersensitivity. Methodological limitations were evaluated with the Downs and Black tool. Crude and adjusted odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated from random‐effects meta‐analyses, followed by subgroup and sensitivity analyses. Thirty studies were included in the review, and 24 datasets with 10 184 patients in the meta‐analyses. Orthodontic treatment had no significant effect on nickel hypersensitivity (n = 11; crude OR 0.99; 95%CI: 0.78–1.25; p = 0.914). However, when confounding from factors such as sex and piercings was taken into account, orthodontic treatment was associated with a lower risk of hypersensitivity (n = 1; adjusted OR 0.60; 95%CI: 0.40–0.80; p < 0.001). This was even more pronounced when orthodontic treatment was performed prior to piercing (n = 7; crude OR 0.35; 95%CI: 0.24–0.50; p < 0.001). Orthodontic treatment seems to have a protective role against nickel hypersensitivity, especially when it precedes piercings.

Candidate Genes for Nonsyndromic Cleft Palate Detected by Exome Sequencing

Nonsyndromic cleft palate only (nsCPO) is a facial malformation that has a livebirth prevalence of 1 in 2,500. Research suggests that the etiology of nsCPO is multifactorial, with a clear genetic component. To date, genome-wide association studies have identified only 1 conclusive common variant for nsCPO, that is, a missense variant in the gene grainyhead-like-3 (GRHL3). Thus, the underlying genetic causes of nsCPO remain largely unknown. The present study aimed at identifying rare variants that might contribute to nsCPO risk, via whole-exome sequencing (WES), in multiply affected Central European nsCPO pedigrees. WES was performed in 2 affected first-degree relatives from each family. Variants shared between both individuals were analyzed for their potential deleterious nature and a low frequency in the general population. Genes carrying promising variants were annotated for 1) reported associations with facial development, 2) multiple occurrence of variants, and 3) expression in mouse embryonic palatal shelves. This strategy resulted in the identification of a set of 26 candidate genes that were resequenced in 132 independent nsCPO cases and 623 independent controls of 2 different ethnicities, using molecular inversion probes. No rare loss-of-function mutation was identified in either WES or resequencing step. However, we identified 2 or more missense variants predicted to be deleterious in each of 3 genes (ACACB, PTPRS, MIB1) in individuals from independent families. In addition, the analyses identified a novel variant in GRHL3 in 1 patient and a variant in CREBBP in 2 siblings. Both genes underlie different syndromic forms of CPO. A plausible hypothesis is that the apparently nonsyndromic clefts in these 3 patients might represent hypomorphic forms of the respective syndromes. In summary, the present study identified rare variants that might contribute to nsCPO risk and suggests candidate genes for further investigation.

Genome-wide transcriptome induced by Porphyromonas gingivalis LPS supports the notion of host-derived periodontal destruction and its association with systemic diseases

Chronic periodontitis (CP) is a prevalent pathogen-associated inflammatory disorder characterized by the destruction of tooth-supporting tissues, and linked to several systemic diseases. Both the periodontopathogen Porphyromonas gingivalis (Pg), and the genetically determined host immune response, are hypothesized to play a crucial role in this association. To identify new target genes for CP and its associated systemic diseases, we investigated the transcriptome induced by Pg in human monocytes using a genome-wide approach. Monocytes were isolated from healthy male volunteers of European origin and challenged with the Pg virulence factor LPS. Array-based gene expression analysis comprising >47,000 transcripts was performed followed by pathway analyses. Transcriptional data were validated by protein and cell surface markers. LPS Pg challenge led to the significant induction of 902 transcripts. Besides known periodontitis-associated targets, several new candidates were identified (CCL23↑, INDO↑, GBP 1/4↑, CFB↑, ISG20↑, MIR155HG↑, DHRS9↓). Moreover, various transcripts correspond to the host immune response, and have been linked to cancer, atherosclerosis and arthritis, thus highlighting the systemic impact of CP. Protein data of immunological markers validated our results. The present findings expand understanding of Pg elicited immune responses, and indicate new target genes and pathways of relevance to diagnostic and therapeutic strategies.

Retrospective investigation of gingival invaginations@@@Retrospektive Untersuchung der Gingivaduplikatur: Part II: microbiological findings and genetic risk profile@@@Teil II: Mikrobiologische Befunde und genetisches Risikoprofil

Background and objectiveGingival 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 methodsA 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).ResultsThe 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.ConclusionThis 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.ZusammenfassungHintergrund und FragestellungDie Gingivaduplikatur ist eine häufig auftretende Veränderung nach Zahnextraktion und kieferorthopädischem Lückenschluss. Aufgrund ihrer interdentalen Lokalisation und bisweilen ausgeprägten Tiefenentwicklung wurde sie mit einer erschwerten Mundhygienefähigkeit in Verbindung gebracht. Im Teil I dieser Artikelserie konnten der zeitliche Faktor und die Lokalisation der Extraktion als potenzielle wichtige Einflussfaktoren für die Entstehung der Gingivaduplikatur identifiziert werden. Ziele der vorliegenden Studie waren einerseits die Analyse des mikrobiologischen Keimspektrums einer Gingivaduplikatur im Vergleich zu Poolproben aus dem Sulkus von Ramfjord-Zähnen und andererseits, ob ein Zusammenhang zwischen einer genetischen Variation des spezifischen proinflammatorischen Markers Interleukin-1 (IL-1) und dessen Rezeptorantagonisten (IL-1-RN) sowie einer positiven Raucheranamnese und der Entstehung einer Duplikatur besteht.Probanden und MethodikDreißig Patienten mit (n=16) und ohne (n=14) Gingivaduplikatur wurden mit Hilfe eines kommerziell erhältlichen Testverfahrens (micro-IDent®Plus, Hain Lifescience, Nehren) auf das Vorhandensein von elf parodontal pathogenen Bakterienstämmen untersucht. Die genetische Evaluation erfolgte durch das GenoType® IL-1 Testverfahren (Hain Lifescience).ErgebnisseDie Ergebnisse der mikrobiologischen Untersuchung ergaben, dass Gingivaduplikaturen in Einzelfällen ein verändertes Keimspektrum bzw. höhere Werte einiger Bakterienspezies aufweisen können als die jeweilige Poolprobe. In der Gruppe ohne Gingivaduplikatur lag nur bei etwa 14% ein IL-1-Polymorphismus vor, wohingegen der Wert mehr als doppelt so hoch war (35%) in der Gruppe mit einer Gingivaduplikatur. Eine Kombination beider Polymorphismen, IL-1 und seines Rezeptorantagonisten, wurde nur bei Patienten mit Gingivaduplikatur (25%) detektiert. Interessanterweise wurde bei einer positiven Raucheranamnese ein statistisch signifikanter Anstieg der Ausprägung einer Gingivaduplikatur diagnostiziert.SchlussfolgerungDie vorliegende retrospektive Studie lässt die Hypothese zu, dass eine Gingivaduplikatur mit einem veränderten mikrobiologischen Keimspektrum und genetischen IL-1-Polymorphismus vergesellschaftet sein kann. Darüber hinaus wurde der Tabakkonsum als weiterer Einflussfaktor für die Ausprägung einer Duplikatur identifiziert.