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ABSTRACT: Background and objectiveOne 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 ClassII
therapy.
Subjects and methodsA total of 130lateral cephalograms—before and after orthodontic treatment—were available from 65adolescent classII 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.
ResultsNo 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).
ConclusionIf 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.
Hintergrund und ZielEine Möglichkeit zur Bestimmung der Wachstumsrichtung der Mandibula ist die Betrachtung des Kiefergelenks und der Mandibulabewegung
als Viergelenkgetriebe. Dabei wird das Wachstum als Streckung des Getriebes verstanden. Ziel war es zu überprüfen, ob ein
Zusammenhang zwischen der Art der biomechanischen Wachstumsstreckung und der Änderung der Bisslage nach Klasse-II-Therapie
besteht.
Probanden und MethodikVon 65 jugendlichen Klasse-II-Patienten mit offenem bzw. tiefem Biss standen 130 Fernröntgenseitenbilder vor und nach ihrer
kieferorthopädischen Behandlung zur Verfügung. Die beiden Fernröntgenseitenbilder des jeweiligen Patienten wurden in der Okklusionsebene
überlagert. Neben kephalometrischen Werten und der vertikalen Nullpunktstufe aus der biomechanischen Analyse der Frontzahnstellung
wurden zusätzlich drei Längen und drei Winkel ermittelt.
ErgebnisseEs wurden keine Korrelationen zwischen den kephalometrischen Daten und den von uns erhobenen Längen und Winkeln gefunden.
Während sich für die Längen kein signifikanter Unterschied in den Gruppen zeigte, unterschieden sich alle drei Winkel signifikant
(p < 0,05).
SchlussfolgerungIn Bezug zur Getriebestreckung während des Wachstums wurde dies so interpretiert, dass bei den Patienten mit anfangs offenem
Biss die Okklusionsebene im Verlauf der Behandlung absank, während sich bei Patienten mit anfangs tiefem Biss die Okklusionsebene
anhob.
KeywordsAngle Class II–Open bite–Deep bite–Change in intermaxillary relationship–Constancy in biomechanical function–Growth extension–Temporomandibular joint
SchlüsselwörterAngle-KlasseII–Offener Biss–Tiefer Biss–Bisslageveränderung–Biomechanische Funktionskonstanz–Wachstumsstreckung–Kiefergelenk
Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie 05/2012; 72(5):358-370. · 0.86 Impact Factor
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ABSTRACT: 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.
Fortschritte der Kieferorthopädie 10/2011; 72(5):358-70. · 0.89 Impact Factor
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ABSTRACT: We conducted a temporal gene expression analysis with type I collagen in the coronoid process, alveolar process and mandibular angle of the rat. We observed gene expression cross-sectionally across different important physiological time points in the rat postnatal life in order to observe in which developmental stage mandibular development mainly occur. This study indicates prominent type I collagen expression at day 10 postpartum in the mandibular ramus and at day 21 in the alveolar process. These findings correspond well with previously obtained data from proliferation studies in facial bone suggesting that craniofacial growth in the rat occurs mainly between days 10 and 21.
Annals of anatomy = Anatomischer Anzeiger: official organ of the Anatomische Gesellschaft 02/2010; 192(2):96-100. · 0.88 Impact Factor
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ABSTRACT: Impacted teeth remain embedded in the jawbone beyond the normal eruption time with completed root growth. They can often get infected or damage neighboring teeth. Information about the three-dimensional position of impacted teeth is invaluable in orthodontic diagnosis and treatment planning. The purpose of this prospective study was to assess the feasibility of using magnetic resonance imaging (MRI) for the three-dimensional localization of impacted teeth in children and adults. The study included 39 patients from the pediatric age group with different tooth impactions and seven adults with impacted wisdom teeth. MRI yielded a clear separation between impacted teeth and the surrounding tissue, and the position and angulation of impacted teeth in all three spatial dimensions could be assessed. Compared to conventional radiography, dental MRI provides the advantage of full volumetric morphology accompanied by complete elimination of ionizing radiation, which is particularly relevant for repeated examinations of the pediatric group.
Clinical Oral Investigations 05/2009; 14(2):169-76. · 2.36 Impact Factor
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ABSTRACT: To investigate the daily rhythm of cortisol levels in saliva of school children.
Probands (10-14 years, both genders) were recruited via personal contact and school visits. Exclusion criteria included hormonal and dental treatments during the trial, pharmaceuticals containing cortisol, or poor oral hygiene. Each volunteer collected 20 saliva samples during one day at defined times starting immediately after waking up and ending at night. Additionally, they completed a sampling diary. Saliva samples were analysed in duplicate using a commercial cortisol luminescence kit.
Cortisol concentration in saliva followed a daily rhythm. Within 20 minutes after waking up cortisol reached the highest level of 9.69 (+/-3.89) nmol/L. After 90 minutes cortisol concentration decreased linearly by 50% and stagnated at 4.14 (+/-1.93) nmol/L for 3 to 8 hours. Thereafter, levels decreased gradually reaching almost zero after 14 hours. Overall, no gender-specific differences in saliva cortisol levels were observed except for 3 time points: 3, 10 and 11 hours after waking.
This study establishes guidelines for a normal secretion pattern, plus explores pain level measurements and their correlation to saliva cortisol levels in this age group.
International Dental Journal 03/2009; 59(1):12-8. · 0.96 Impact Factor
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ABSTRACT: The purpose of this study was to compare the frictional properties of four self-ligating metal brackets, Speed, Damon 2, In-Ovation, and Time, with those of three conventionally ligated metal brackets, Time, Victory Twin, and Discovery. The self-ligating Time bracket can also be used as a conventionally ligated bracket. Friction was tested 20 times for each bracket/wire combination using a Zwick testing machine with stainless steel wires in three different wire dimensions (0.017 x 0.025, 0.018 x 0.025, and 0.019 x 0.025 inches). All brackets had a 0.022 inch slot and the prescription of an upper first premolar. The data were statistically analysed with unsigned comparisons of all bracket/wire combinations using the Mann-Whitney U-test and the Games-Howell post hoc test. The results showed almost all brackets to have the lowest frictional force with a wire dimension of 0.018 x 0.025 inch. Friction of the self-ligating brackets using wire with a dimension of 0.018 x 0.025 inches was 45-48 per cent lower than with 0.017 x 0.025 and 0.019 x 0.025 inch wires. Friction of the conventionally ligated brackets showed a 14 per cent or less reduced friction with 0.018 x 0.025 inch wire compared with 0.017 x 0.025 and 0.019 x 0.025 inch wires. The self-ligating metal brackets showed lower frictional forces with a 0.018 x 0.025 inch wire than conventionally ligated brackets, whereas conventionally ligated brackets showed lower friction with 0.017 x 0.025 and 0.019 x 0.025 inch wire. Friction values vary with different bracket/archwire combinations and, therefore, the choice of a bracket system for treatment should consider the correct wire dimension to produce the lowest possible frictional forces.
The European Journal of Orthodontics 12/2008; 30(6):654-60. · 0.89 Impact Factor
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ABSTRACT: 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 bone maturity. In this animal model, female primiparous inbred rats (LEW.1A) were used. The gravid animals 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 FTP. Thus, group TP showed the most marked negative changes both for cleft frequency and 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 and growth inhibition could not be proved for the vitaminoid thiocyanate.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 12/2008; 59 Suppl 5:17-25. · 2.27 Impact Factor
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ABSTRACT: The Wuerzburg Post is a new post-and-core restoration system designed to eliminate the weak parts of post-and-core restorations and the associated problems, respectively. In contrast to conventional posts, the Wuerzburg Post is a short and thick post, which no longer relies on cementation or luting for retention in the root, but on stress-free positive locking, which it achieves by means of a post which can be spread into a predefined and form-congruent undercut cavity. The second key feature is an annular groove which runs in the dentin, girded by a corresponding structure, ensuring regular force transmission and stress dissipation, as opposed to the classic ferrule design. There are two versions: one with a machined core which can be prepared like a classic build-up to support crowns and bridges, and another one with a 2.25 mm ball end to connect to common dies which can be integrated into removable prostheses. As the system utilizes prefabricated parts made from Titanium, a precise fit is ensured, enabling the user to restore teeth quickly and easily. Over the course of the past three years, 129 posts were inserted, most commonly on upper and lower incisors and canines. The main application was restoration of fractured telescopes. During the observation period, five failures were observed. Two of the failiures did not cause significant damage to the tooth, and were subsequently immediately repairable. The survival rate amounts to over 95% after three years under risk.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 12/2008; 59 Suppl 5:105-15. · 2.27 Impact Factor
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ABSTRACT: Objective: To investigate the relation between dental status, BMI and systemic diseases and to evaluate the risk factors for having a higher BMI. Materials and Methods: Apopulation based cross sectional study of 6248 subjects aged 18-80 years (response of 68.8%, n=4310) was conducted in the Study of Health in Pomerania (SHIP-0). Socio-demographic, medical and oral health information was recorded by 5 dentists at two similarly equipped medical/dental services in the cities of Greifswald and Stralsund. Bivariate statistics, multivariate statistics, linear and logistic regression models were performed to assess the relationship between following covariates: gender, educational level, family status, social activities, income, quality of life (SF-12), smoking, alcohol abuse, diabetes, renal disease, high blood pressure, dental status and high physical activity. Results: Significant risk factors for subjects having a higher BMI were: high blood pressure (OR=2.28), diabetes (OR=2.10), educational level (low: OR=1.49; medium OR=1.27), male (OR=1.32) and former smoker (OR=1.20). whereas young age, being single and being dentate (natural teeth, replaced teeth or fixed teeth) was shown to be protective for having a "high" BMI. Conclusion: The most important predictors of BMI were shown to be social and medical factors. Dental factors are most significantly influenced by social factors and also exhibit an important impact on BMI.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 12/2008; 59 Suppl 5:5-16. · 2.27 Impact Factor
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ABSTRACT: Polyamines are widespread distributed all over in living organisms. In Thalassiosira pseudonana 10 N-aminopropyl transferase like nucleotide sequences exists. It is assumed that these sequences are involved in the biomineralization of the diatom shell. The cDNA of the sequences were cloned, recombinant overexpressed and assayed with decarboxylated S-adenosylmethionine and several radioactive labelled polyamines. However, only a spermidine synthase and a thermospermine synthase were found to be enzymatically active in an in vitro assay. Both enzyme activities could be recognized in the crude extracts of Thalassiosira pseudonana and Cyclotella meneghiana. In further investigations the kinetics of the thermospermine synthase was determined and a site-specific mutagenesis of the bindig cavity of decarboxylated S-adenosylmethionine was carried out.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 12/2008; 59 Suppl 5:27-37. · 2.27 Impact Factor
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ABSTRACT: During recent years, gene expression analyses based on DNA chip technologies have allowed for the genome-wide identification of genes potentially associated with growth processes in a variety of organs. The present study aims to identify genes differentially expressed in the growing temporomandibular joint cartilage by means of transcriptome analyses.
In total, the condylar cartilage of 32 rats comprising 4 age groups (newborn, 10 days, 21 days, 8 weeks) were used for analysis. Transcriptome analyses were carried out using Affymetrix Expression Arrays (Rat Genome 230 2.0 Arrays). The availability of high-quality RNA preparations from homogeneous tissue samples is a fundamental precondition of successful transcriptome analyses using DNA arrays. An optimised preparation protocol allowed RNA isolation of sufficient quality which was validated using capillary electrophoresis. RNA collected from 8 test animals of the 4 age groups respectively was mixed in equimolar RNA pools which served for the transcriptome analyses using Affymetrix arrays.
Statistical analysis of the gene expression data indicated the existence of genes differentially regulated in the growing temporomandibular cartilage. This evidence, however, requires validation by RT-PCR using individual animals' RNA. Preliminary candidate genes belong, among others, to the groups of matrix-degrading proteases, protease inhibitors and genes involved in cell growth, apoptosis and bone remodelling.
These differentially expressed genes in TMJ growth identified using DNA array technology may possibly contribute to a better understanding of growth biology and provide an approach to necessary therapy.
Advances in Medical Sciences 05/2008; 53(2):191-7.
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ABSTRACT: Primary stability is crucial to implants used for orthodontic anchorage. Bone condensing to enhance primary stability is controversial.
Fourteen Frialit-2-stepped screw and cylinder implants were placed in the median palatine sutures of 22 cadaveric human heads. In half of both types, the implant bed was prepared using a Frialit Bone Condenser. Primary implant stability was evaluated using non-invasive resonance frequency analysis. Moreover, the bone-implant contact area was examined histomorphometrically and radiographically.
Bone condensing yielded a slightly, yet not significantly increased implant stability quotient compared with a conventional technique. In spongy bone, a significant histomorphometric increase of bone-implant contact (P<0.0001) and a significant increase of radiographic density was revealed for both implant types, while no significant changes were observed within the compact area.
The study shows that bone condensing yields an improved histologic implant-bone contact only in spongy bone, which was paralleled by radiographic-densitometric findings.
Clinical Oral Implants Research 02/2008; 19(1):42-7. · 2.51 Impact Factor
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ABSTRACT: The purpose of this study was to compare the frictional properties of two self-ligating aesthetic brackets, Opal (Ultradent Products) and Oyster (Gestenco Int.), with those of four conventionally ligated aesthetic brackets, Transcend (3M Unitek), Inspire (Ormco), Allure (GAC Int.), and Image (Gestenco Int.). Friction was tested with different wire dimensions and qualities [stainless steel (SS) wire 0.017 x 0.025 inches; SS 0.019 x 0.025 inches; TMA 0.019 x 0.025 inches] using a Zwick testing machine. All brackets had a 0.022-inch slot and the prescription of an upper first premolar of the Roth system (tip: 0 degrees, torque: -7 degree). Each bracket/archwire combination was tested 10 times and each test was performed with a new bracket/wire sample that was pulled through twice. Additionally, two sets of 30 Opal brackets each were aged with an ageing machine under standardized conditions for 9-10 and 18-20 months, respectively. Friction of the aged brackets was tested with identical wire dimensions and qualities using the same testing procedure. All data were statistically analysed with unsigned comparisons of all bracket/wire combinations using GLM and the Games-Howell post hoc test. The results showed Opal brackets to have the lowest frictional forces for all wire dimensions and qualities. Furthermore, friction was lower at a significant level (P </= 0.05) compared with all other brackets. Only the Oyster bracket had similar values in combination with a 0.019 x 0.025 inch SS wire. Aged Opal brackets showed higher values than new ones, but still lower frictional forces than the four conventional aesthetic brackets. Friction was comparable with the new Oyster bracket.
The European Journal of Orthodontics 08/2007; 29(4):359-65. · 0.89 Impact Factor
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ABSTRACT: Numerous ritual acts involving the skull result in orofacial changes. The present study focuses on ritual acts of Brazilian Zoé Indians. A distinct deformation effect of the ritual act (wearing a lip-plug) on the morphology of the orofacial system is demonstrated and documented using jaw models. The studies show that the lip-plug significantly influences tooth position and jaw growth. While the maxilla displays palatal displacement of the lateral incisors and elevation of the palate, retraction occurs in the mandible depending upon plug size. Additionally, both the plug and the nutritional habits of the Indians induce marked abrasion of all teeth. Moreover, it is shown that the duration of lip-plug wear is an essential determinant of sustained orofacial changes.
Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(3):304-8. · 1.86 Impact Factor
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ABSTRACT: The aim of the study was to investigate potential differences between the physical development and the dental age in two groups of male pupils from two schools with different socio-economic profiles in the city of Torun (Poland).
A total number of 286 school boys (age: 9-12 years) was examined: Group A consisted of 104 pupils of a private school (mean age: 10.36-/+0.1 years), group B were 182 normally intellectually developed, non-handicapped pupils (10.59-/+0.1 years) of a therapeutic school for children with specific learning difficulties like dyslexia, dysgraphy, ADHD or severe speech disorders. The parameters of the physical development (body height, body weight) and the dental age assessed by eruption were evaluated based on a biological frame of reference and percentile charts.
The two groups showed distinct disparities in physical and dental development: the mean values of body height were significantly higher in group A than group B (p<0.02). In addition, differences in percentile distributions of body height, body mass and dental age showed statistical significance (p<0.001, 0.01 and 0.01, respectively). The relationship between body height/body mass and dental age was not statistically significant (p>0.3).
The pronounced disparities concerning physical and dental development within boys of different socio-demographic background should be taken into account by health professionals. No correlation was found between physical and dental development.
European Journal of Paediatric Dentistry. Official Journal of the Italian Society of Paediatric Dentistry. 01/2007; 7(4):169-73. · 0.44 Impact Factor
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ABSTRACT: A novel bone formation material based on hydroxyapatite-xerogel is presented. With the use of the innovative sol-gel technology this material is produced in the low-temperature range by the addition of silicon dioxide; in its structure it mimics to a great extent the natural bone matrix. This results in high osteoconductivity and an osteoprotective effect as well as in complete biodegradation corresponding to bone formation in the course of natural bone remodelling. Two case reports are presented.
Folia morphologica 03/2006; 65(1):84-8. · 0.52 Impact Factor
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ABSTRACT: A new synthetic bone grafting substitute (NanoBone, ARTOSS GmbH, Germany) is presented. This is produced by a new technique, the sol-gel-method. This bone grafting substitute consists of nanocrystalline hydroxyapatite (HA) and nanostructured silica (SiO2). By achieving a highly porous structure good osteoconductivity can be seen. In addition, the material will be completely biodegraded and new own bone is formed. It has been demonstrated that NanoBone is biodegraded by osteoclasts in a manner comparable to the natural bone remodelling process.
Folia morphologica 03/2006; 65(1):54-5. · 0.52 Impact Factor
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ABSTRACT: Regenerative medicine provides different therapy alternatives alongside gold standard autogenous grafts for the treatment of periodontal or peri-implant osseous defects. Continuing progress in the field of alloplastic bone substitutes has yielded promising solutions to the appropriate indications with the membrane technique either alone or in combination with enamel matrix derivatives. Their clinical outcomes, however, still require critical discussion.
Folia morphologica 03/2006; 65(1):66-9. · 0.52 Impact Factor
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ABSTRACT: The temporary nature of orthodontic implants demands optimisation of size and design in order to minimise damage and risk to the patient. Slender and shorter miniscrews offer the advantage over conventional implants of easier and more ubiquitous positioning with minimised risk of injury to neighbouring anatomical structures such as tooth roots, nerves or vessels. The question is raised, however, as to what extent these advantages are gained at the price of diminished stability or a more unfavourable bone interface. In order to evaluate the screw/bone interface, 14 orthodontic miniscrews (Mondeal Medical Systems, diameter: 1.5 mm, length: 9 mm) were inserted into the right and left mandibles of 7 pigs (Sus scrofa domestica). Bone fluorochromes were administered in a defined order for polychrome sequencing. The samples gathered after 70 days were analysed using histological techniques and fluorescence microscopy. The lower part of the self-tapping thread displayed undisturbed bone apposition. Fluorescence microscopy revealed remodelling and bone apposition within the thread grooves.
Folia morphologica 03/2006; 65(1):70-1. · 0.52 Impact Factor
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ABSTRACT: Hydroxyapatite (HA) ceramics are widely used for bone reconstruction. They are osteoconductive and serve as structural scaffolds for the deposition of new bone. Generally, scaffold materials should be degradable as they affect the mechanical properties of the reconstructed bone negatively. Degradation by osteoclasts during the bone remodelling process is desirable but often does not take place. In the current study we analysed by light microscopy the degradation of two granular HA implants in critically sized defects in the mandibula of Goettingen mini-pigs five weeks after implantation. Bio-Oss consists of sintered bovine bone and NanoBone is a synthetic HA produced in a sol-gel process in the presence of SiO2. We found that both biomaterials were degraded by osteoclasts with ruffled borders and acid phosphatase activity. The osteoclasts created resorption lacunae and resorptive trails and contained mineral particles. Frequently, resorption surfaces were in direct contact with bone formative surfaces on one granule. Granules, especially of NanoBone, were also covered by osteoclasts if located in vascularised connective tissue distant from bone tissue. However, this usually occurred without the creation of resorption lacunae. The former defect margins consisted of newly formed bone often without remnants of bone substitutes. Our results show that the degradation of both biomaterials corresponds to the natural bone degradation processes and suggest the possibility of complete resorption during bone remodelling.
Folia morphologica 03/2006; 65(1):43-8. · 0.52 Impact Factor
