Browsing by Author "Proff, Peter"

One way of determining the direction of growth of the mandible is to consider the temporomandibular joint and movement of the mandible as a four-joint gear system, regarding growth then as an extension of the gear system. Our aim was to examine any correlations between the type of biomechanical growth extension and change in the maxilomandibular relation after Class II therapy. A total of 130 lateral cephalograms-before and after orthodontic treatment-were available from 65 adolescent class II patients with open bite or deep bite. The two lateral cephalograms from each patient were superimposed on the occlusal plane. Cephalometric values and the vertical base point deviation were determined from biomechanical analyses, together with three distances and three angles. No correlation between the cephalometric data and distances or angles were observed. Although there were no significant differences in the distances, we did note significant differences in all three angles (p < 0.05). If gear system extension during growth is considered, this can be interpreted as meaning that the occlusal plane of those patients with an initially open bite dropped during treatment, but that it rose in patients with an initially deep bite.

The study aimed at to induce cleft-lip-alveolus-palate (CLAP) applying procarbazine in rat fetuses at the 14(th) day of pregnancy, to supply thiocyanate and/or folic acid Sufficient for preventive treatment and Subsequently to investigate cleft extent in the palatal area as well as boric Maturity. In this animal model, female primiparous inbred rats (LEW.IA) Were used. The gravid animal were separated into treatment groups: group K (Control), group P (procarbazine), group TP (thiocyanate and procarbazine) and group FTP (folic acid, thiocyanate, procarbazine). The results reveal that procarbazine may induce clefts in the palate area. Clefts Occurred most frequently in group TP and mainly comprised subtotal clefts of the posterior secondary palate. As for palatal length, group FTP displayed the longest palate which was significantly different only from group K. A different picture was shown for the secondary palate with group TP displaying the shortest Values which were significantly different from those in groups K, P, and FTR Thus, group TP showed the most marked negative changes both for cleft frequency arid palatal length as compared to group K and the other groups. The preventive application of either thiocyanate (TP) or thiocaynate and folic acid combined (group FTP) failed to completely prevent cleft formation in the palate area. In conclusion, a preventive effect on palatal clefts arid growth inhibition Could not be proved for the vitaminoid thiocyanate.

Objective: Methionine is an essential amino acid and pivotal for normal growth and development. However, previous animal studies have shown that excessive maternal intake of methionine causes growth restrictions, organ damages, and abnormal growth of the mandible in newborn animals. However, the effect of excessive methionine on the development of the cranial growth plate is unknown. This study investigated histological alterations of the cranial growth plate induced by high methionine administration in newborn rats. Design: Twenty pregnant dams were divided into a control and an experimental group. The controls received a diet for rats and the experimental group was fed from the 18th gestational day with a special manufactured high methionine diet for rats. The high methionine diet was maintained until the end of the lactation phase (day 20). The offspring of both groups were killed at day 10 or 20 postnatally and their spheno-occipital synchondroses were collected for histological analysis. Results: The weight of the high-dose methionine treated experimental group was considerably reduced in comparison to the control group at day 10 and 20 postnatally. The cartilaginous area of the growth plate and the height of the proliferative zone were markedly reduced at postnatal day 10 in the experimental group. Conclusions: In summary, the diet-induced hypermethioninemia in rat dams resulted in growth retardations and histomorphological changes of the spheno-occipital synchondrosis, an important craniofacial growth centre in newborns. This finding may elucidate facial dysmorphoses reported in patients suffering from hypermethioninemia. (C) 2012 Elsevier Ltd. All rights reserved.

Centric relation prematurities of frontal teeth are frequently found with patients who have severe orthodontic anomalies or received extensive restorative treatment. They can cause a range of symptoms ranging from Loosening of the teeth to temporomandibular disorders (TMD). The objective of this work has been to derive a mathematical description of the mandibular and periodontal forces generated by anterior prematurities for different incisor relations. In order to quantify the effect of contact area (location and inclination) and the tooth inclination, a two-dimensional mathematical approach was used. Vectorisation of the forces and bending moments makes it possible to predict under which conditions the load increase mainly affecting the anterior teeth can and may cause localized pain and eventually Loosening and flaring/crowding of the upper/lower incisors and under which conditions the temporomandibular joint wilt suffer a large increase in retrusive force, which potentially Leads to TMD. For 10 patients with anterior prematurities, analysis of the incisor relation was carried out. For all cases the conclusions drawn from the mathematical model were in full agreement with the reported symptoms, which could be successfully treated. (C) 2007 Elsevier GmbH. All rights reserved.

The goal of the study was to examine the effects of a mechanical (orthodontic force simulation by static compressive loading) and a bacterial (endotoxins from a heat-inactivated gram-negative periodontal pathogen) stressor on the expression patterns of factors that are key to regulating osteoclastogenesis and bone remodeling. Three experimental groups were formed with fifth-passage periodontal ligament (PDL) fibroblasts treated by the static application of compressive force (2 g/cm(2)), heat-inactivated aggregatibacter actinomycetemcomitans (1 x 10(7) cells), or both of these stressors combined. Real-time polymerase chain reaction (RT-PCR) was used to study gene expression of IL-6, IL-8, COX-2, IGF-1, VEGF, and MMP-13 in the 3 groups. Protein levels of COX-2, prostaglandin E2 (PGE(2)), and IL-8 production were quantified using immunoblotting and enzyme-linked immunosorbent assay (ELISA). The mechanical stressor upregulated the genes of COX-2, IL-8, IGF-1, and MMP-13 in PDL fibroblasts and the bacterial stressor upregulated IL-6, IL-8, COX-2 and MMP-13. Both stressors in combination upregulated VEGF and caused COX-2 gene expression to increase further; the latter effect was also detected at the protein level and indirectly via the enhanced production of PGE(2). We noted that the posttranscriptional regulation of IL-8 was induced by the mechanical stressor and influenced by PGE(2). While mechanical-stressor application increased the gene expression of COX-2, IL-8, and VEGF in the presence of the bacterial stressor, IL-8 production was posttranscriptionally regulated by the mechanical stressor, whereas COX-2 expression correlated with enhanced production of the inflammatory tissue hormone PGE(2), which exerted a suppressive effect on endotoxin-induced IL-8 production.

For the physiological intact stomatognathic system, the three main functional states (occlusal articular functions, free mandibular movements, and ideal. bolus function) were biomechanically discussed concerning the structure of movement, rolling-gliding characteristics, and force transfer in the temporomandibular joint (TMJ). In all three cases, rolling is not possible in the TMJ since the instantaneous rotational axis is positioned outside of the joint - rolling is not necessary because the TMJ is not loaded by appreciable forces. In the aged stomatognathic system with a lost discus and considerable Loads in the TMJ, however, the attrition of the joint is eased by rolling movement at the articulating surfaces. The destruction of the discus can be seen as a physiological adaptation which brings back the joint to an original odontogen condition. (C) 2007 Elsevier GmbH. All rights reserved.

The aim of this study was to evaluate tooth and periodontal damage in subjects wearing a tongue piercing (TP) in comparison to matched control subjects without tongue piercing. Members of the German Federal Armed Forces who had TP (group TP) and a matched control group (group C) volunteered to take part in the study. The time in situ, localization and material of TP were documented. Dental examinations included DMF-T, oral hygiene, enamel fissures (EF), enamel cracks (EC) and recessions. Statistical analysis was determined by chi (2) test and the t test. Both groups had 46 male subjects (mean age 22.1 years). The piercings had been in situ for 3.8 +/- 3.1 years. Subjects in the TP group had a total of 1,260 teeth. Twenty-nine subjects had 115 teeth (9.1%) with EF (67% lingual). In group C (1,243 teeth), 30 subjects had 60 teeth with EF (4.8%, 78% vestibular) (p < 0.01). Thirty-eight subjects belonging to group TP had EC in 186 teeth (15%). In group C, 26 subjects with 56 teeth (4.5%) were affected by EC (p < 0.001). Twenty-seven subjects in group TP had 97 teeth (7.7%) with recessions. Lingual surfaces of anterior teeth in the lower jaw were affected most frequently (74%). In group C, 8 subjects had 19 teeth (1.5%) with recessions (65% vestibular). Differences between the two groups were statistically significant (p < 0.001). Tongue piercing is correlated with an increased occurrence of enamel fissures, enamel cracks and lingual recessions. Patients need better information on the potential complications associated with tongue piercing.

Morphological. parameters of the temporomandibular joint (TMJ) of Cercopithecus mona were analyzed by sagittal medial/lateral slicing of the entire joint. The slice contours of the osseous structures of the joint surfaces were approximated by circles. In this manner, the main parameter of the protrusive cranial border guidance, the protrusive dimeric link chain (DLC), could be measured. In each joint, all slices yielded protrusive DLCs which were nearly parallel to each other. In mediat/lateral direction atl. parts of the joints participate in force transmission in initial protrusive cranial border function. (C) 2007 Elsevier GmbH. All rights reserved.

Meaningful, reliable and valid mRNA expression analyses by real-time quantitative PCR (RT-qPCR) can only be achieved, if suitable reference genes are chosen for normalization and if appropriate RT-qPCR quality standards are met. Human periodontal ligament (hPDL) fibroblasts play a major mediating role in orthodontic tooth movement and periodontitis. Despite corresponding in-vitro gene expression studies being a focus of interest for many years, no information is available for hPDL fibroblasts on suitable reference genes, which are generally used in RT-qPCR experiments to normalize variability between samples. The aim of this study was to identify and validate suitable reference genes for normalization in untreated hPDL fibroblasts as well as experiments on orthodontic tooth movement or periodontitis (Aggregatibacter actinomycetemcomitans). We investigated the suitability of 13 candidate reference genes using four different algorithms (geNorm, NormFinder, comparative ΔCq and BestKeeper) and ranked them according to their expression stability. Overall PPIB (peptidylprolyl isomerase A), TBP (TATA-box-binding protein) and RPL22 (ribosomal protein 22) were found to be most stably expressed with two genes in conjunction sufficient for reliable normalization. This study provides an accurate tool for quantitative gene expression analysis in hPDL fibroblasts according to the MIQE guidelines and shows that reference gene reliability is treatment-specific.