Peter Proff

Publications of Peter Proff

• Effect of excessive methionine on the development of the cranial growth plate in newborn rats.

  Authors: Piero Römer, Jens Weingärtner, Benjamin Desaga, Dietmar Kubein-Meesenburg, Claudia Reicheneder, Peter Proff

  Archives of oral biology. 03/2012;

  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 growthOBJECTIVE: 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.

• An Investigation about the Influence of Bleaching on Shear Bond Strength of Orthodontic Brackets and on Enamel Colour.

  Authors: Isabell Immerz, Peter Proff, Piero Roemer, Claudia Reicheneder, Andreas Faltermeier

  ISRN dentistry. 01/2012; 2012:375849.

  The aim of the study was to investigate the effect of bleaching on the colouration of tooth enamel and shear bond strength of orthodontic ceramic brackets based upon current whitening practice. TheThe aim of the study was to investigate the effect of bleaching on the colouration of tooth enamel and shear bond strength of orthodontic ceramic brackets based upon current whitening practice. The bleaching and bonding techniques were performed on extracted bovine teeth for the investigation of their colorimetric spectrum and the adhesive bond strength on surface enamel. One group was designated as the control group with no pre-treatment. Another group was treated with a 45% hydrogen peroxide solution prior to bonding. The difference in colour was expressed as the Euclidian distance ΔE. The resulting shear bond strength was analyzed and evaluated by scores of Adhesion Remnant Index. Statistical analysis was performed using the Kruskall-Wallis and post-hoc test. The colorimetric analysis revealed statistically significant differences between original and bleached as well as bleached and debonded teeth setting off a blue colour shift. Furthermore, statistically there was no significant difference noted in bonding strength between non-treated surfaces and those treated with peroxide. It can be concluded that peroxide pre-treatment does result in colour differences of teeth. Bonding and debonding procedures seem to have no statistically significant influence on the enamel colour using current materials.

• Effects of hypodontia on craniofacial structures and mandibular growth pattern.

  Authors: Amelia Kreczi, Peter Proff, Claudia Reicheneder, Andreas Faltermeier

  Head & face medicine. 12/2011; 7:23.

  This study was performed to examine craniofacial structures in persons with hypodontia and to reveal any differences, that may occur, when agenetic teeth are only found in the maxilla, the mandibleThis study was performed to examine craniofacial structures in persons with hypodontia and to reveal any differences, that may occur, when agenetic teeth are only found in the maxilla, the mandible or in both jaws. The groups consistent of 50 children (33 girls, 17 boys) aged between 9 and 13.5 years were analyzed and assigned to three subgroups. Group 1 = upper jaw hypodontia. Group 2 = lower jaw hypodontia. Group 3 = hypodontia in both jaws. Eleven angular and three index measurements from lateral encephalographs and two linear measurements from dental blaster casts were calculated. All data was statistically analyzed, parameters with p < 5% were investigated for each subgroup respectively. In comparison with standards the study group showed bimaxillary retrognathism and a reduction of the lower anterior facial height. Moreover both overbite and overjet significantly increased. Other values laid within the normal ranges. Evaluating results of the subgroups, differences in the means of SNA, SNB and overjet between the groups were observed.Analysis of the mandibular growth pattern revealed, that neither vertical nor horizontal patterns are dominant in hypodontia patients. In certain dentofacial parameters differences between persons with hypodontia and such with full dentition exist. According to our findings agenetic teeth may have a negative influence on the saggital development of a jaw and the lower face and may be responsible for increased overbites. This should receive attention in orthodontic treatment of hypodontia patients.

• Changes in condylar cartilage after anterior mandibular displacement in juvenile pigs.

  Authors: Tomasz Gredes, Heike Mack, Alexander Spassov, Christiane Kunert-Keil, Matthew Steele, Peter Proff, Florian Mack, Tomasz Gedrange

  Archives of oral biology. 10/2011;

  Adaptive remodelling of the mandibular condyle in response to mandibular advancement is the mechanism exploited by orthodontic forward displacement devices. OBJECTIVE: This work investigated theAdaptive remodelling of the mandibular condyle in response to mandibular advancement is the mechanism exploited by orthodontic forward displacement devices. OBJECTIVE: This work investigated the expression of collagens, matrix metalloproteinases and vascular endothelial growth factor during this process. DESIGN: Twenty juvenile pigs were randomly divided into two experimental groups, where the treatment group was fitted with mandibular advancement splints, and the control group was not. Changes in the mRNA content of condylar cartilage tissue was then were measured by real-time PCR using specific primers after 4weeks of treatment. RESULTS: The temporal pattern of the expression of Col1 and MMP13 during condylar adaptation coincided with that during natural condylar growth. The amount of the expression of Col10 during condylar adaptation was significantly lower (p<0.05), whereas the expression of Col2, MMP8 and VEGF was significantly higher compared to natural growth (p<0.05). CONCLUSIONS: It is suggested that condylar adaptation in growing pigs triggered by mandibular forward positioning results not only from passive adaptation of cartilage, but also involves growth affected processes. Our results showed that mechanical strain produced by mandibular advancement induced remodelling and revascularization in the posteriocranial mandibular condyle. These results are mostly consistent with former published histological and histomorphometrical analyses.

• Strontium promotes cell proliferation and suppresses IL-6 expression in human PDL cells.

  Authors: Piero Römer, Benjamin Desaga, Peter Proff, Andreas Faltermeier, Claudia Reicheneder

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 10/2011;

  This study was designed to investigate the effect of strontium on human PDL cells in vitro. Strontium is used to treat osteoporosis because of its bone formation promoting effect on osteoblast cells.This study was designed to investigate the effect of strontium on human PDL cells in vitro. Strontium is used to treat osteoporosis because of its bone formation promoting effect on osteoblast cells. This investigation presents evidence that strontium promotes PDL cell proliferation. Simultaneously, strontium suppresses the expression of the inflammation-promoting cytokine IL-6. The observed effect of strontium on PDL cells supports its use it in guided dental tissue regeneration.

• Morphofunctional aspects of dental implants.

  Authors: Georg Meyer, Jochen Fanghänel, Peter Proff

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 10/2011;

  Although oral implantology is among the most beneficial developments of modern dentistry, the widely spread opinion that the long-term outcome of implants is superior to that of natural teeth hasAlthough oral implantology is among the most beneficial developments of modern dentistry, the widely spread opinion that the long-term outcome of implants is superior to that of natural teeth has been refuted. To evade uncritical extractions, the morphofunctional properties of natural teeth and implant-supported restorations are compared from a proprioceptive and occlusal trauma perspective. The periodontal ligament of natural teeth provides the central nerve system with feedback for sensory perception and motor control. Conversely, the lack of such proprioception causes lower tactile sensitivity and less coordinated masticatory muscle activity in implant-borne restorations and makes them more prone to occlusal overload and possible subsequent failure. Moreover, occlusal anomalies may be conducive to parafunctional activity, craniomandibular disorder, tinnitus, and headache. Oral implantology, therefore, has to take appropriate account of occlusal conditions and the biomechanical and neuromuscular aspects of masticatory function.

• Measurement of tooth and implant mobility under physiological loading conditions.

  Authors: Julian Boldt, Werner Knapp, Peter Proff, Kurt Rottner, Ernst-Jürgen Richter

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 10/2011;

  In vivo measurement of the mobility of teeth under physiological loading has been subject of research for years. Comparing the deflection under load of dental implants with teeth provides valuableIn vivo measurement of the mobility of teeth under physiological loading has been subject of research for years. Comparing the deflection under load of dental implants with teeth provides valuable input for designing restorations spanning both teeth and implants. Physiological force rise time of about 50-100ms and displacement of 10-100μm requires high spatial and temporal resolution of the measurement set-up. Using an optical system attached to the teeth/implants to be measured and a light source attached to a point of reference, displacement of teeth and implants under axial and lateral loading was measured on a series of volunteers. Axial displacement of teeth shows strong time dependence consistent with (hydraulic) damping not observed for lateral loads. Displacement under lateral loading was found to be about one order of magnitude higher than under axial load. For dental implants elastic deflection was observed in axial and lateral direction without measurable influence of the load rise time. For purely axial loading, dental implants and teeth show similar deflection under physiological force rise time but for lateral loading the considerably difference between teeth and implant may put some restrictions on the construction of tooth-implant-bridges, especially for teeth in the anterior region.

• The two main theories on dental bruxism.

  Authors: Michael Behr, Sebastian Hahnel, Andreas Faltermeier, Ralf Bürgers, Carola Kolbeck, Gerhard Handel, Peter Proff

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 10/2011;

  Bruxism is characterized by non-functional contact of mandibular and maxillary teeth resulting in clenching or grating of teeth. Theories on factors causing bruxism are a matter of controversy inBruxism is characterized by non-functional contact of mandibular and maxillary teeth resulting in clenching or grating of teeth. Theories on factors causing bruxism are a matter of controversy in current literature. The dental profession has predominantly viewed peripheral local morphological disorders, such as malocclusion, as the cause of clenching and gnashing. This etiological model is based on the theory that occlusal maladjustment results in reduced masticatory muscle tone. In the absence of occlusal equilibration, motor neuron activity of masticatory muscles is triggered by periodontal receptors. The second theory assumes that central disturbances in the area of the basal ganglia are the main cause of bruxism. An imbalance in the circuit processing of the basal ganglia is supposed to be responsible for muscle hyperactivity during nocturnal dyskinesia such as bruxism. Some authors assume that bruxism constitutes sleep-related parafunctional activity (parasomnia). A recent model, which may explain the potential imbalance of the basal ganglia, is neuroplasticity. Neural plasticity is based on the ability of synapses to change the way they work. Activation of neural plasticity can change the relationship between inhibitory and excitatory neurons. It seems obvious that bruxism is not a symptom specific to just one disease. Many forms (and causes) of bruxism may exist simultaneously, as, for example, peripheral or central forms.

• The influence of electron beam irradiation on colour stability and hardness of aesthetic brackets.

  Authors: Julia Faltermeier, Philipp Simon, Claudia Reicheneder, Peter Proff, Andreas Faltermeier

  European journal of orthodontics. 04/2011;

  Electron beam irradiation can be used to improve the mechanical properties of polymers. The aim of this study was to investigate the influence of electron beam irradiation with an energy dose of 100Electron beam irradiation can be used to improve the mechanical properties of polymers. The aim of this study was to investigate the influence of electron beam irradiation with an energy dose of 100 kGy on the mechanical properties and colour stability of conventional polymer brackets and experimental filled composite brackets. The conventional brackets tested were Aesthetik-Line, Brillant, and Envision. The experimental brackets contained urethane dimethacrylate, as a monomer matrix and functional silane-treated SiO(2) fillers with a filler content of either 10 (Exper 1) or 40 (Exper 2) vol per cent. The influence of electron beam post-curing on Vickers hardness (VH) of the polymer brackets was investigated. Additionally, a possible discolouration of the brackets after electron beam irradiation was determined according to the three-dimensional L* a* b* colour space. The irradiated brackets were compared with untreated control groups. Statistical analysis was performed using the Wilcoxon test. With the exception of Brillant brackets, all investigated brackets showed a significant enhancement of VH after electron beam post-curing. However, the brackets suffered a significant increase in discolouration. Aesthetik-Line brackets showed the highest discolouration, ΔE, and Exper 2 brackets the lowest ΔE values. The discolouration of the examined brackets differed significantly. These results demonstrate that the mechanical properties of polymer brackets could be modified by electron beam irradiation. Nevertheless, clinical use of electron beam post-curing might be restricted because of unacceptable colour changes.

• Effect of strontium on human Runx2+/- osteoblasts from a patient with cleidocranial dysplasia.

  Authors: Piero Römer, Michael Behr, Peter Proff, Andreas Faltermeier, Claudia Reicheneder

  European journal of pharmacology. 03/2011; 654(3):195-9.

  Strontium represents a new generation of anti-osteoporotic agents that exert anti-catabolic and anabolic effects on bone cells at once. We used strontium in vitro in order to examine its potential toStrontium represents a new generation of anti-osteoporotic agents that exert anti-catabolic and anabolic effects on bone cells at once. We used strontium in vitro in order to examine its potential to stimulate bone marker transcription and hydroxyapatite formation on isolated Runx2(+/-) osteoblasts from a patient with cleidocranial dysplasia. This disease is evoked by heterozygous mutations of Runx2, an important transcription factor for osteoblast maturing and transcription of osteogenic genes, which results in insufficient gene dosage of Runx2. This genetic defect is responsible, for example, for patent fontanels, sometimes throughout the life, supernumerary teeth, and aplasia or hypoplasia of clavicles and mimics symptoms of hypophosphatasia. In this trial, we investigated the effect of strontium on gene expression of bone marker proteins, the formation of hydroxyapatite and the cell proliferation of strontium-treated Runx2(+/-)-osteoblasts. Unlike normal osteoblasts, gene expression of bone marker proteins was not affected in strontium-treated Runx2(+/-) osteoblasts, while improved hydroxyapatite formation was noted in the extracellular matrix. A WST-1 cell proliferation assay with strontium-treated Runx2(+/-)-osteoblasts showed that strontium induces cell proliferation and growth. This effect might be responsible for the improved mineralisation of the extracellular matrix of strontium-treated Runx2(+/-)-osteoblasts observed.

• Survey of congenitally missing teeth in orthodontic patients in Eastern Bavaria.

  Authors: Michael Behr, Peter Proff, Michael Leitzmann, Manuela Pretzel, Gerhard Handel, Gottfried Schmalz, Oliver Driemel, Torsten E Reichert, Michael Koller

  European journal of orthodontics. 02/2011; 33(1):32-6.

  This retrospective study examined the occurrence of congenitally missing permanent teeth and the need for dental treatment in the Regensburg University Medical Centre of Eastern Bavaria. Using aThis retrospective study examined the occurrence of congenitally missing permanent teeth and the need for dental treatment in the Regensburg University Medical Centre of Eastern Bavaria. Using a dental administration software tool, a total of 1442 patients who presented for orthodontic treatment between 1994 and 2006 were identified. After exclusion of 89 patients with incomplete records, 1353 subjects (635 males and 718 females) remained for analysis. Of these, 1130 had no missing permanent teeth, 52 had cleft lips, 110 had one to two teeth missing, 34 had three to five missing teeth, and 27 had greater than or equal to six missing teeth. The analyses focused on the type and number of missing teeth and on differences in the severity of dental agenesis according to gender and to referrals from various geographic regions around Regensburg. The data were statistically analysed using two-tailed tests. The following teeth were most frequently missing: tooth 35 (5.9 per cent), 45 (5.1 per cent), 22 (4.0 per cent), 12 (3.6 per cent), 15 (3.1 per cent), and 25 (3.0 per cent). No statistically significant difference in gender was found for one to two missing permanent teeth (low degree), hypo- or oligodontia (severe degree), or cleft lip. The odds ratio (OR) of presenting with hypo- or oligodontia compared with no missing teeth was higher among subjects originating from geographic regions outside Regensburg than from those from Regensburg, and it was statistically significantly higher for patients from Passau {OR = 3.53 [95% confidence interval (CI) = 1.18-10.52]} and Landshut [OR = 3.65 (95% CI = 1.22-10.99)]. The high prevalence and severe degree of dental agenesis of permanent teeth found in these groups of patients likely reflects distinct referral patterns for patients originating from geographic regions outside Regensburg. These data reinforce the need for a specialized dental treatment centre with the capacity to adequately serve a large rural area in Eastern Bavaria.

• The bond strength of the resin-to-zirconia interface using different bonding concepts.

  Authors: Michael Behr, Peter Proff, Carola Kolbeck, Sabine Langrieger, Johannes Kunze, Gerhard Handel, Martin Rosentritt

  Journal of the mechanical behavior of biomedical materials. 01/2011; 4(1):2-8.

  This study investigated the shear bond strength (SBS) and the tensile bond strength (TBS) of the zirconia-to-resin interface using different cement bonding concepts. Coplanar zirconia specimens wereThis study investigated the shear bond strength (SBS) and the tensile bond strength (TBS) of the zirconia-to-resin interface using different cement bonding concepts. Coplanar zirconia specimens were bonded to CoCr-cylinders measuring 5 mm in diameter and 3 mm in height. All bonding areas were first sandblasted with 110 μm Al(2)O(3) (0.28 MPa, 10 s). SBS and TBS were determined after 24 h and 90 d of water storage as well as after 12,000 thermal cycles (TC, 5°/55 °C, 17 d). The bonding concepts consisted of the application of a silane coupling agent, tribological silica coating (Rocatec system), cements or primers containing phosphone, mono-phosphate, or di-phosphate, and a combination of silica coating and primer. Bond strength higher than 10 MPa was considered clinically sufficient. SBS measured with each bonding concept surpassed this value, except control and MaxCem after 90 d. In contrast, TBS values were rather different. The application of a silane coupling agent alone showed very low values in the TBS test. Silica coating was only sufficient after 90 d of water storage and when combined with phosphate-esters or phosphone-containing primers. Bonding agents based on di-phosphates or phosphones showed stable TBS values of less than 10 MPa under different aging conditions. The predominant mode of failure was adhesive failure at the ceramic surface. None of the investigated bonding concepts of the zirconia-to-resin interface provided clinically sufficient tensile bond strength. SBS values were inadequate for a sufficient ranking.

• Electron-beam irradiation of polymer bracket materials.

  Authors: Andreas Faltermeier, Michael Behr, Claudia Reicheneder, Peter Proff, Piero Römer

  American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 01/2011; 139(1):e7-e11.

  Electron-beam irradiation can be used to influence the properties of polymers. Electron beams cause cross-linking that enhances the molecular mass of the polymer; this leads to branched chains until,Electron-beam irradiation can be used to influence the properties of polymers. Electron beams cause cross-linking that enhances the molecular mass of the polymer; this leads to branched chains until, ultimately, a 3-dimensional network is formed. The aim of this study was to evaluate the effect of electron-beam irradiation on polymer bracket materials. Since polymers are commonly used materials for brackets, polyoxymethylene, polycarbonate, and polyurethane were chosen for this study. The acceleration voltage of the electron-beam device was 10 MeV, and the energy dose was 100 kGy with an electron accelerator (BGS beta gamma service, Rhodotron, Bruchsal, Germany). Three-medium wear, fracture toughness, and Vickers hardness tests were performed. The irradiated samples were compared with untreated control groups. Polycarbonate and polyurethane bracket materials have enhanced fracture toughness and Vickers hardness after electron-beam irradiation of 100 kGy and 10 MeV. Polyoxymethylene bracket materials showed significantly lower fracture toughness values after irradiation compared with the untreated control group. Polyoxymethylene had the best mechanical properties, followed by polycarbonate and polyurethane. Almost the same effects could be measured during the 3-medium wear test. Electron-beam postcuring improved Vickers hardness and fracture toughness of polymers with lower mechanical properties (polycarbonate and polyurethane). Polyoxymethylene, with sufficient hardness and fracture toughness, could not be improved with electron-beam postcuring.

• Development dependent collagen gene expression in the rat cranial base growth plate.

  Authors: Piero Römer, Jens Weingärtner, J Camilo Roldán, Peter Proff, Claudia Reicheneder

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 08/2010; 192(4):205-9.

  The spheno-occipital synchondrosis is part of the cranial base growth plate and is of crucial importance in craniofacial development. In this investigation, we studied changes in collagen geneThe spheno-occipital synchondrosis is part of the cranial base growth plate and is of crucial importance in craniofacial development. In this investigation, we studied changes in collagen gene expression in the spheno-occipital synchondrosis in order to identify the developmental stages most important for extracellular matrix production and ossification of the rat cranial base growth plate. Gene transcripts of type II and X collagen were most abundant at day 10 postnatally in the spheno-occipital synchondrosis. This observation is assumed to be due to intrinsic genetic factors and local environmental factors.

• Malocclusion, mastication and the gastrointestinal system: a review.

  Authors: Peter Proff

  Journal of orofacial orthopedics = Fortschritte der Kieferorthopädie : Organ/official journal Deutsche Gesellschaft für Kieferorthopädie. 03/2010; 71(2):96-107.

  The relationship between malocclusion and the gastrointestinal system has only been examined occasionally, while several pertinent studies have addressed the chewing function as a functional linkThe relationship between malocclusion and the gastrointestinal system has only been examined occasionally, while several pertinent studies have addressed the chewing function as a functional link between oral structures and the gastrointestinal tract. Following an overview of the physiological masticatory process, the available evidence regarding associations among dental status, chewing function and gastrointestinal disorders are summarized. Finally, a review of the relationships between orthodontic deformities and mastication is presented.

• Evaluation of alternative polymer bracket materials.

  Authors: Julia Krauss, Andreas Faltermeier, Michael Behr, Peter Proff

  American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 03/2010; 137(3):362-7.

  Polymer brackets still have some disadvantages because of decreased wear resistance and hardness. The aim of this study was to investigate the mechanical properties of alternative bracket polymers;Polymer brackets still have some disadvantages because of decreased wear resistance and hardness. The aim of this study was to investigate the mechanical properties of alternative bracket polymers; urethane-dimethacrylate, high-density polyethylene, and an experimental bracket polymer (EBP) consisting of polyethylene and a copolymer were tested. Polycarbonate and polyoxymethylene brackets served as controls. The mechanical properties of urethane-dimethacrylate, high-density polyethylene, EBP, polycarbonate, and polyoxymethylene bracket materials were evaluated after thermocycling (6000 x 5 degrees C-55 degrees C) in a mastication device before testing. Three medium-wear, fracture toughness, and Vickers hardness tests were performed. High-density polyethylene had the highest values of wear and the lowest values of fracture toughness and Vickers hardness. The urethane-dimethacrylate bracket material and the EBP had better mechanical properties than polycarbonate. The polyoxymethylene bracket material had the highest values of fracture toughness and Vickers hardness, and the lowest values of wear compared with the other investigated polymers. High-density polyethylene seems to be unsuitable as bracket material because it demonstrated excessive wear and insufficient fracture toughness. Polyoxymethylene had the best performance during mechanical testing.

• Variations in the inclination of the condylar path in children and adults.

  Authors: Claudia Reicheneder, Tomas Gedrange, Uwe Baumert, Andreas Faltermeier, Peter Proff

  The Angle orthodontist. 10/2009; 79(5):958-63.

  Objective: To test the null hypothesis that there are no differences between children and adults in the condylar path inclination angle on the right and left sides. Materials and Methods: A group ofObjective: To test the null hypothesis that there are no differences between children and adults in the condylar path inclination angle on the right and left sides. Materials and Methods: A group of 80 children aged 6 to 10 years (subgroups I through V, according to chronologic age) was compared with an adult group with regard to the condylar path inclination angle (CPIA) on the right and left sides. The CPIA was measured using the ultrasonic JMA-System for registration. Results: During development of the temporomandibular joint the condylar path inclination angle increased with age in the subgroups of children. A significant difference was found in the CPIA between the groups of adults and children. In the group with the oldest children (mean age: 10.3 years) the condylar path inclination angle had reached 81.87% on the right side and 78.85% on the left side compared with the adult group at a 5 mm protrusive path. In the pooled group of children the CPIA amounted to 73.08% on the right side and 72.13% on the left side compared with the values for the adults. No significant difference was found between the right and left CPIA in any group. Conclusion: The hypothesis is rejected. The CPIA on the right and left sides increased with age in the group of children and was significantly smaller in the group of children compared with the group of adults.

• Mandibular prognathism caused by acromegaly - a surgical orthodontic case.

  Authors: Martin Gosau, Corinna Vogel, Antonios Moralis, Peter Proff, Johannes Kleinheinz, Oliver Driemel

  Head & face medicine. 09/2009; 5(1):16.

  ABSTRACT: A 22-year-old man presented for orthodontic surgery because of mandibular prognathism. Clinical symptoms suggested acromegaly, and diagnosis was verified by an endocrinologist as well as byABSTRACT: A 22-year-old man presented for orthodontic surgery because of mandibular prognathism. Clinical symptoms suggested acromegaly, and diagnosis was verified by an endocrinologist as well as by radiograph. Bilateral mandibular prognathism often represents the first and most striking physical characteristic of acromegaly; usually, it is also the main reason why patients seek help from orthodontists or maxillo-facial surgeons. This case report recapitulates the clinical and histopathological findings in pituitary growth hormone (GH) adenomas and emphasises their importance in surgical orthodontic planning. Mandibular prognatism, macroglossia and abnormal growth of hands and feet represent strong indicators for the diagnosis of acromegaly. This disease and its complications not only affect the entire body but increase mortality if the pituitary gland tumour remains untreated.

• Shear and tensile bond strength comparison of various contemporary orthodontic adhesive systems: an in-vitro study.

  Authors: Claudia A Reicheneder, Tomas Gedrange, Alexandra Lange, Uwe Baumert, Peter Proff

  American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 05/2009; 135(4):422.e1-6; discussion 422-3.

  INTRODUCTION: The purpose of this study was to compare the shear and tensile bond strengths of 8 common adhesive systems for bonding in orthodontics. METHODS: One hundred sixty freshly extractedINTRODUCTION: The purpose of this study was to compare the shear and tensile bond strengths of 8 common adhesive systems for bonding in orthodontics. METHODS: One hundred sixty freshly extracted bovine mandibular permanent incisors were randomly divided into 8 groups. Self-ligating esthetic Damon 3 brackets (Ormco, Orange, Calif) were bonded by using the following adhesive systems: Quick Bond (chemically and light-cured; Forestadent, Pforzheim, Germany), Blugloo (Ormco), Enlight LV (Ormco), Kurasper F (Kuraray Dental, Frankfurt, Germany), Transbond LR (3 M Unitek, Monrovia, Calif), Light Bond (Reliance Orthodontic Products, Itasca, Ill), and Fuji Ortho LC (GC America, Alsip, Ill). After 24 hours, half of each group was debonded measuring the shear bond strength and half measuring the tensile bond strength. RESULTS: Blugloo showed the best shear bond strength values, whereas Transbond LR and Quick Bond (chemically and light-cured) had the lowest. Tensile strength was the highest with Fuji Ortho LC and the lowest with Quick Bond (chemically and light-cured) and Kurasper F. The tensile strength of light-cured Quick Bond was about 47% lower than that of Fuji Ortho LC. CONCLUSIONS: Blugloo, Fuji Ortho LC, Light Bond, and Enlight LV are among the materials of choice for bonding fixed orthodontic appliances to teeth. All bond strength values were clinically satisfactory except for the tensile strength of chemically and light-cured Quick Bond and Kurasper F.

• The molecular mechanism behind bone remodelling: a review.

  Authors: Peter Proff, Piero Römer

  Clinical oral investigations. 04/2009;

  Bone is a connective tissue and guarantees protection and support of organ function. Contrary to the common view, bone is a dynamic tissue that constantly undergoes turnover in order to maintainBone is a connective tissue and guarantees protection and support of organ function. Contrary to the common view, bone is a dynamic tissue that constantly undergoes turnover in order to maintain stability and integrity. In this process called bone turnover or bone remodelling, two effector cell types are involved. Osteoclasts, specialised for bone resorption, and osteoblasts, responsible for bone formation, are key players in bone turnover. In the past decade, a lot of information about signal pathways, osteoblast-osteoclast communication and osteoclast activation concerning bone remodelling has arisen. In this publication, we aim to review molecular and biochemical insights with respect to the bone remodelling process. The bone remodelling process is of fundamental importance for craniofacial growth, orthodontic tooth movement and regenerative dentistry.